HK1114702A - Methods and apparatus for efficient digital broadcast signaling in a wireless communications system - Google Patents

Description

Method and apparatus for efficient digital broadcast signal transmission in a wireless communication system

RELATED APPLICATIONS

[0001] The benefit of U.S. provisional patent applications S.N.60/659,509, S.N.60/696,847 and S.N.60/697,865, entitled METHODS and applications FOR EFFICIENT environmental monitoring SYSTEM SIGNALING IN AN OFDM wireless communication SYSTEMs, filed on 8.3.2005, 7.6.2005 and 7.8.2005, all of which are hereby incorporated by reference.

Technical Field

[0002] The present invention relates to digital broadcasting and, more particularly, to broadcasting information such as video or audio signals to a plurality of users within an area served by one or more base stations.

Background

[0003] In some wireless communication systems, it may be desirable to broadcast digital video or other information signals, such as radio display broadcasts, to mobile users via the downlink. As the mobile node moves through the system, it is desirable for the user of the mobile node to be able to receive and decode continuous or nearly continuous program signals, such as television programs to be decoded and displayed in real time. One method used is to broadcast the same signal simultaneously to neighboring base stations within the system with timing synchronization between the base station transmitters, which is controlled to the symbol level. Different neighboring base stations transmit the same information on the same pitch (tone) at the same time. This method has the following disadvantages: a high level of symbol transmission timing synchronization between base stations is required so that signals received from different base stations do not differ in time by more than a fraction of a symbol transmission time period.

[0004]Fig. 1 is a diagram 100 illustrating an example in which two neighboring base stations (BS a 102, BS B104) simultaneously transmit the same signal carrying modulation symbols carrying coded digital broadcast information bits using a single carrier frequency (C) and the same subcarrier frequency, such as a pitch. In fig. 1, Mobile Node (MN)106 is located equidistant from BS a 102 and BS B104. With respect to MN 106, S is arranged as shown in FIG. 1 with respect to line 108_A110 and S_B112, signal A (S) from BS A102_A)110 and a signal B (S) from BS B104_B)112, where line 108 represents the equidistant point between the two base stations (102, 104). Distance is used herein to indicate the propagation time of a signal from one point to another, e.g., from a base station to a mobile node. Conditions in the environment such as reflective objects may cause the signal propagation time to differ from the straight-line distance between points. To facilitate the description of the distance of use. For signals to be received from different base stationsSymbol timing synchronization maintained between signals requires close synchronization of the BSs (102, 104) and maintenance of a level of synchronization between the base stations. S_A110 and S_B112 each include payload information (114, 116), such as a modulation symbol value portion, and a cyclic prefix portion (CP) (118, 120) for synchronization, respectively. Signal (S)_A110 and S_B112) Combined over the air link and the MN 106 receives and decodes the combined signal, recovering the information bits.

[0005]Fig. 2 is a diagram 200 illustrating a received signal (S) when the MN 106 is not equidistant from two BSs (102, 104)_A 110’、S_B112') will tend to lose synchronization with respect to each other, the amount of synchronization loss being a function of the difference in signal path distance between the MN and each BS. From the perspective of the MN 106, S_B112' relative to the signal S_A110' delay. The MN 106 can recover a received signal in which there is at least some overlap between the cyclic prefixes, e.g., where the signal delay difference between the two signals does not exceed the cyclic prefix duration. S_A110 ' includes a payload portion 114 ' and a CP portion 118 '; s_B112 ' includes a payload portion 116 ' and a CP portion 120 '. The diagram 200 illustrates a partial overlap between the CP 118 'and CP 120' from the perspective of the MN 106 receiving the two signals 110 'and 112'.

[0006]Fig. 3 is a diagram 300 illustrating an example in which the MN 106 is located such that it is from S_A110 "does not have a cyclic prefix 118" from S_B112 "overlap so that S is_A110' and S_B112 "and vice versa. Typically, the MN 106 will not be able to recover and decode such broadcast signals due to the degradation in signal quality caused by the interference. Figure 4 shows a known method for remedying this problem. The length of the cyclic prefix is increased, allowing for a larger overlap area. However, the cyclic prefix represents signaling overhead, and thus any increase in cyclic prefix lengthCorresponds to a reduction in the throughput of information bits in the system.

[0007]The timing of the signals received by the MN 106 in fig. 3 and 4 are compared. In FIG. 3, S_A110 ' includes payload information 114 ' and CP 118 ', and S_B112 "includes payload information 116" and CP120 ". In FIG. 4, S_A110 * includes payload information 114 * and CP 118 *, and S_B112 * includes payload information 116 * and CP120 *. Note that the CPs (118 * and 120 *) are longer in duration than the CPs (118 "and 120"), however, the payload information portions (114 * and 116 *) are shorter in duration than the payload information portions (114 "and 116"). The increase in CP duration represented by fig. 4 brings about overlap between CPs (118 * and 120 *), contributing to the likelihood of successful recovery of payload information, however, at the cost of payload reduction.

[0008] Fig. 5 is a diagram 500 illustrating an exemplary OFDM downlink pitch with a pitch spacing. N exemplary downlink tones are shown in tone spacing increment f 514 (tone 1502, tone 2504, tone 3506, tones 4508, … …, tone N-1510, tone N512). One method that can be used to compensate for the capacity loss due to the larger cyclic prefix length is to make the pitch spacing smaller than would otherwise be possible, so that more pitch is inserted into a given band. This approach allows more information bits to be packed into the same frequency capacity, assuming that all the fundamental tones can still be received reliably. This approach to reducing the pitch interval is disadvantageous for mobility, and in particular for high-rate mobility users such as users traveling in a car, bus or train, since motion can skew the perceived signal frequency making it difficult to reliably decode closely spaced genes.

[0009] In view of the above discussion, it should be appreciated that known simultaneous broadcast methods, such as digital video broadcasting, typically involve some or all of the following undesirable consequences: (i) there is a need to maintain symbol transmission timing synchronization between different base stations at a high level, e.g., for the duration of the cyclic prefix or less; (ii) the cyclic prefix needs to be relatively long, which results in an undesirable amount of overhead; and (iii) the use of narrow pitch intervals tends to interfere with the reception and processing of the mobile device, which may result in insufficient support for mobility. Furthermore, when the channel conditions are not uniform, the quality may be easily degraded.

[0010] In view of the problems discussed above, new methods and apparatus are needed to facilitate downlink broadcasts, such as downlink digital video broadcasts, in an OFDM wireless communication system that reduce and/or overcome one or more of the problems discussed above.

Disclosure of Invention

[0011] Various embodiments are directed to transmitter apparatus and methods, e.g., methods and apparatus for transmitting broadcast signals, such as television, radio, advertisements, and/or other programming or information. The methods and apparatus may be implemented using transmitter apparatus, such as a base station, that broadcasts the same information, such as program content, at different times.

[0012] According to one feature of various embodiments, a receiver may receive signals from each base station at different times and then combine the information recovered from the received signals to form a complete program or set of information to be provided to a user.

[0013] There are various options for implementing the receive and combine features. If the receiver cannot successfully decode a signal, such as a program segment, received from a first base station, it can go to another base station and receive a signal carrying the same information, such as a program segment. After combining the signals received from the different base stations, the receiver can successfully decode the combined signals and recover the transmitted information, such as broadcast program segments.

[0014] According to other combining options, the receiver may receive and decode signals from a first transmitter, such as a first base station, and then switch to receiving and decoding signals from another transmitter, such as a second base station. The handover may, but need not, be in response to: since a receiver, such as a wireless terminal, is moved away from a first base station and towards a second base station, the signal from the first base station cannot be decoded. Because of the time difference between transmissions, program segments or other information that cannot be successfully recovered from one base station may be recovered from another base station.

[0015] Program segments recovered from signals received from different base stations may be combined to form a complete program, such as a television program, which may be provided to a user of a device receiving the broadcast segments.

[0016] The methods and apparatus of the various embodiments provide a wide range of possibilities and different transmitters transmitting the same information content at different times may use the same or different carrier frequencies.

[0017] Although base station timing may be synchronized within a cyclic prefix period, various embodiments do not require such a fine degree of synchronization between neighboring base stations. In some embodiments, the methods of the various embodiments may be used with neighboring base station transmitters that are not timing synchronized to a cyclic prefix duration, and in some cases may not even be synchronized within a symbol duration.

[0018] Some features relate to a transmitter apparatus and other features relate to a receiver apparatus. The transmitter may be implemented in the base station but need not be. The receiver methods and apparatus may be implemented in a wireless terminal, but need not be limited to such devices, and may be used in devices that include a wireless receiver and that include a wired connection to another device or network. Various embodiments are also directed to data storage devices, such as memory devices, that store one or more routines which may be used to implement one or more steps and circuits, such as integrated circuit chips, which may be used to implement one or more modules or apparatus.

[0019] While various embodiments have been discussed in the foregoing summary, it should be appreciated that not all embodiments necessarily include the same features, and that some of the features described above may not be necessary in some embodiments but may be desirable. Many additional features, embodiments and benefits are described in the detailed description that follows.

Drawings

[0020] Fig. 1 shows an example in which two adjacent base stations simultaneously transmit the same signal, carrying modulation symbols carrying coded digital broadcast information bits, using a single carrier frequency and the same sub-carrier frequency, such as a pitch;

[0021] FIG. 2 illustrates that when a mobile node is not equidistant from two base stations, the received signals will tend to lose synchronization with respect to each other, where the amount of synchronization loss is a function of the difference in signal path distance between the mobile node and each base station;

[0022] figure 3 illustrates an example in which the mobile node is located such that the cyclic prefix of a received first base station downlink signal does not overlap with the cyclic prefix of a received second base station downlink signal, such that the downlink signal received from the first base station interferes with the downlink signal received from the second base station, and vice versa;

[0023] FIG. 4 illustrates a known method for remedying the problem of FIG. 3, wherein the length of the cyclic prefix is increased, allowing for a larger overlap region; however, overhead is also increased;

[0024] FIG. 5 illustrates an exemplary OFDM downlink pitch having a pitch spacing;

[0025] FIG. 6 illustrates an exemplary wireless communication system that supports downlink digital broadcasts, such as radio (audio) or video program broadcasts;

[0026] corresponding to fig. 6, fig. 7 depicts different base station carrier transmissions versus time;

[0027] fig. 8 is a flow chart of an exemplary method of operating a wireless terminal to receive downlink broadcast signal transmissions from a plurality of neighboring base stations, wherein for each base station, the same information is transmitted using a different carrier frequency;

[0028] fig. 9 illustrates another exemplary system that is similar to the system of fig. 6, however, the timing structure for the base station downlink signal of the fig. 9 embodiment differs slightly from the timing structure corresponding to the fig. 6 embodiment;

[0029] corresponding to fig. 9, fig. 10 depicts different base station carrier transmissions versus time;

[0030] fig. 11 is a flow chart of an exemplary method of operating a wireless terminal to receive downlink broadcast signal transmissions from a plurality of neighboring base stations, wherein for each base station, the same information is transmitted using a different carrier frequency;

[0031] FIG. 12 illustrates another feature of some embodiments; a base station using multiple carriers with different intensity levels may transmit different broadcast information, such as different videos, on each different carrier;

[0032] FIG. 13 illustrates an exemplary base station;

[0033] FIG. 14 illustrates an exemplary wireless terminal;

[0034] FIG. 15 is a diagram of an exemplary base station;

[0035] FIG. 16 illustrates an exemplary wireless terminal such as a mobile node;

[0036] fig. 17 is a diagram of an exemplary system in which each base station supports three carriers at different power levels, and the order of power levels is different for two neighboring base stations;

[0037] fig. 18 is a diagram of an exemplary system in which each base station supports three sectors and three carriers within each sector, the three carriers being at different power levels within each sector, and the order of power levels being different with respect to two neighboring sectors;

[0038] FIG. 19 is a flow chart 1900 of an exemplary communication method;

[0039] fig. 20 is a flow chart 2000 of an exemplary method of operating a base station;

[0040] fig. 21 is a diagram of an exemplary base station, such as an access node;

[0041] FIG. 22 is a diagram illustrating several exemplary sets of program information;

[0042] FIG. 23 is a flow chart of an exemplary method of operating a wireless terminal;

[0043] FIG. 24 is a flow chart of an exemplary method of operating a wireless terminal;

[0044] FIG. 25 is a diagram of an exemplary wireless terminal, such as a mobile node;

[0045] FIG. 26 is a diagram of an exemplary communication system, such as an OFDM communication system supporting program broadcasting;

[0046] FIG. 27 is a flow chart of an exemplary method of operating a wireless terminal;

[0047] FIG. 28 is a diagram of an exemplary wireless terminal, such as a mobile node;

[0048] FIG. 29 is a flow chart of an exemplary communication method;

[0049] FIG. 30 is a diagram of an exemplary communication system, such as an OFDM communication system supporting program broadcasting;

[0050] fig. 31 is a diagram of an exemplary base station, such as an access node.

Detailed Description

[0051] The methods and apparatus of the various embodiments may be used to provide broadcast services such as television or audio broadcasts, but may also be used to provide multicast services where multicast is a particular type of broadcast. Multicast services are well suited for signaling applications where information is intended to be provided to a specific group of users rather than to each user.

[0052] The methods of the various embodiments may be used to support a wide variety of services including, for example, pay per view services, where paying customers may be provided with sufficient information to decrypt the broadcast signals they pay for access, but not other signals. However, the methods are not limited to these embodiments and may be used in cases where reception, decoding, and use of the broadcast signal are authorized without subscription.

[0053] Fig. 6 illustrates a wireless communication system 600 that supports downlink digital broadcasts, such as radio (audio) or video program broadcasts. The exemplary system 600 includes a plurality of base stations 602, 604(BS a, BS B), each supporting OFDM signal transmission on at least two different carrier frequencies, such as a plurality of carrier frequencies C1, C2, C3. In the example of fig. 6, each base station 602, 604 supports 3 carriers (C1, C2, C3) at different transmission power levels associated with and for each carrier, as represented by the different sized circles surrounding each base station 602, 604. Base station a 602 transmits downlink signals on carriers (C1, C2, C3) at (high, medium, low) power levels, as indicated by circles (606, 608, 610), respectively. The base station B604 transmits downlink signals on carriers (C3, C1, C2) at (high, medium, low) power levels, as indicated by circles (612, 614, 616), respectively. The neighboring base stations 602, 604 use different power level orderings associated with the carriers such that neighboring base stations do not generally use the same power level for the same carrier. Thus, although the neighboring base stations 602, 604 may use the same carriers C1 and C3, they will use different power levels on carriers C1, C3. When another common carrier such as C2 is used, each BS 602, 604 may transmit at the same power level or at a different power level at each BS. Exemplary system 600 also includes a plurality of wireless terminals, such as mobile nodes. An exemplary MN 618 is shown in system 600, and exemplary MN 618 may be moving. Fig. 13 and 15 illustrate exemplary base stations (1300, 1500). Fig. 14 and 16 illustrate exemplary wireless terminals (1400, 1600).

[0054] Two different carriers, such as C1 and C3, from two different neighboring base stations 602, 604 transmit the same broadcast information at different times. The downlink broadcast segment may be, for example, about 20ms long. Two neighboring base stations are not strictly synchronized to the symbol level, but rather there is a very coarse level of synchronization between the two base stations, e.g., synchronization exists at a level that is typically outside of the cyclic prefix used to transmit the symbol, and the BSs 602, 604 may not even be synchronized to within one symbol transmission time period. Fig. 7 includes a graph 700 that depicts different BS carrier transmissions on a vertical axis 702 versus time on a horizontal axis 704. Drawing 700 includes an exemplary BS a carrier C1 Downlink (DL) broadcast transmission segment sequence 706 (segment 1708, segment 2710, segment 3712, … …, segment N714) and an exemplary BS B carrier C3 downlink broadcast transmission segment sequence 716 (segment 1718, segment 2720, segment 3722, … …, segment N724). Fig. 7 illustrates an exemplary transmission timing of a segment (708, 710, 712, … …, 714) from BS a using carrier frequency C1 and an exemplary transmission timing of a segment (718, 720, 722, … …, 724) from BS B using carrier frequency C3. The same information is transmitted from different BSs, but at different times and using different carriers C1 and C3, respectively. For example, the downlink broadcast segment 1708 transmitted by BS a 602 using carrier C1 carries the same information as the downlink broadcast segment 1718 transmitted by BS B604 using carrier C3; however, the two segments are offset in time. In some embodiments, two segments carrying the same information are offset in time by more than one segment duration. In some embodiments, the time difference between the end of transmission of a segment from a first base station, such as the end of transmission of DL broadcast segment 1708, and the start of transmission of a corresponding segment from a neighboring base station, such as the start of DL broadcast segment 1718, may be, for example, less than one segment time interval but separated by one or several symbol transmission time periods, such as 2, 3, 10, or more symbol transmission time periods. In some embodiments, two segments carrying the same information are offset in time by less than one segment duration, but separated by one or several symbol transmission time periods, such as 2, 3, 10, or more.

[0055] Fig. 8 is a flow chart 800 of an exemplary method of operating a wireless terminal to receive downlink broadcast signal transmissions from a plurality of neighboring base stations, wherein the same information is transmitted for each base station using a different carrier frequency. The wireless terminals and neighboring base stations may be part of an exemplary OFDM communication system. An exemplary wireless terminal may have a single RF receiver chain. Operation begins in step 801, where a WT, such as the exemplary MN 618 of fig. 6, is powered up and initialized. Operation proceeds from step 801 to steps 802 and 804. In step 802, the WT is operated to periodically check for a carrier signal. For example, beacon signals transmitted from the BSs 602, 604 may be monitored, received, and estimated, and the identified first carrier corresponds to a first base station and the identified second carrier corresponds to a carrier of a neighboring base station, wherein the identified second carrier carries the same broadcast information as the identified first carrier but with a timing offset. The first carrier may be, for example, carrier C1 corresponding to BS a 602 of fig. 6, and the second carrier may be carrier C3 corresponding to BS B604 of fig. 6.

[0056] In step 804, the WT is operated to receive downlink broadcast signals on a first carrier C1, e.g., signals from BS a 602 using carrier C1. Next, in step 806, the WT is operated to attempt to decode the received signal. If the decoding was successful in step 808, operation continues back to step 804 for reception of other signals on the same carrier C1. This may be the case, for example, if the WT has sufficient channel quality with respect to BS a 602 using carrier C1. However, if the decoding was unsuccessful, operation proceeds from step 808 to step 810, where the WT changes its receiver to a second carrier, such as carrier C3, which corresponds to BS B604 downlink signaling.

[0057] The wireless terminal is then operated to receive a downlink broadcast signal transmission on the second carrier in step 812. In step 814, the wireless terminal attempts to decode the received signal. If the decoding is successful, operation proceeds from step 816 back to step 812 for receiving and processing other signal transmissions using the second carrier; however, if the decode was unsuccessful, then operation proceeds from step 816 to step 818. In step 818, the wireless terminal is operated to transition to the first carrier and operation returns to step 804 for receiving other signal transmissions.

[0058] Fig. 9 illustrates another exemplary system 900, which is similar to the system of fig. 6. However, the base station downlink signal timing structure for the embodiment of fig. 9 indicated in fig. 10 is slightly different from the timing structure corresponding to the embodiment of fig. 6 indicated in fig. 7. In the example of fig. 10, the same signal transmission from each base station is intentionally spaced apart so that the wireless terminal receiver can receive the same segment from two neighboring base stations in a continuous fashion by switching back and forth between carriers and, in some embodiments, recover the information bits through a combining process.

[0059] The exemplary system 900 includes a plurality of base stations 902, 904(BS a, BS B), each supporting OFDM signals on at least two different carrier frequencies, such as a plurality of carrier frequencies C1, C2, C3. In the example of fig. 9, each base station 902, 904 supports 3 carriers (C1, C2, C3) at different transmission power levels associated with and for each carrier, as represented by the different sized circles surrounding each base station 902, 904. As indicated by circles (906, 908, 910), respectively, base station a 902 transmits downlink signals at (high, medium, low) power levels on carriers (C1, C2, C3). Base station B904 transmits downlink signals at (high, medium, low) power levels on carriers (C3, C1, C2) as indicated by circles (912, 914, 916), respectively. Exemplary system 900 also includes a plurality of wireless terminals, such as mobile nodes. An exemplary MN 918 is shown in the system 900, and the exemplary MN 918 can be mobile.

[0060] In the example of fig. 10, the same signal transmissions from each base station are intentionally spaced apart so that a wireless terminal receiver, such as MN 918, can receive the same segment from two neighboring base stations in a continuous fashion by switching back and forth between carriers and, in some embodiments, recover the information bits through a combining process.

[0061] Fig. 10 includes a diagram 1000 depicting different BS carrier transmissions on a vertical axis 1002 versus time on a horizontal axis 1004. Diagram 1000 includes an exemplary BS a carrier C1 downlink broadcast transmission segment sequence 1006 (segment 11008, segment 21010, segment 31012, … …) and an exemplary BS B carrier C3 downlink broadcast transmission segment sequence 1014 (segment 11016, segment 21018, segment 31020, … …). Fig. 10 illustrates an exemplary transmission timing of a segment (1008, 1010, 1012, … …) from BS a using carrier frequency C1 and an exemplary transmission timing of a segment (1016, 1018, 1020, … …) from BS B using carrier frequency C3. The same information is transmitted from different BSs, but at different times and using different carriers C1 and C3, respectively. For example, downlink broadcast segment 11008 transmitted by BS a 902 using carrier C1 carries the same information as downlink broadcast segment 11016 transmitted by BS B904 using carrier C3; however, the two segments are offset in time. In some embodiments, two segments carrying the same information are offset in time by more than one segment duration. In some embodiments, the time difference between the end of transmission of a segment from a first base station, such as the end of transmission of DL broadcast segment 11008, and the start of transmission of a corresponding segment from a neighboring base station, such as the start of DL broadcast segment 11016, may be, for example, less than one segment time interval, but separated by one or several symbol transmission time periods, such as 2, 3, 10, or more. In some embodiments, for example, the separation in time allows the WT 918 to switch back and forth between two carrier frequencies. In some embodiments, two broadcast segments transmit the same information from different base stations, e.g., via different carriers, and by combining the information from the two broadcast segments, the information being transmitted may be recovered, otherwise, if the segments are available from one base station but not the other, the information may not be recovered.

[0062] In some embodiments, each DL broadcast segment corresponding to a sequence of segments (such as 1008, 1010, 1012, … …) for a given base station and carrier (such as BS a 902 and carrier C1) is spaced and interleaved so that a corresponding sequence of segments (such as 1016, 1018, 1020, … …) transmitted using carrier C3 from a neighboring base station, such as base station BS B904, may also be received and processed by the same wireless terminal receiver, which includes a single RF chain switching between carriers.

[0063] In some embodiments, for a given base station and carrier, multiple different broadcast channels may be supported, e.g., each broadcast channel comprises a sequence of spaced segments, and the channels may be interleaved in time, e.g., channel 1 broadcast segment 1, channel 2 broadcast segment 1, channel 3 broadcast segment 1, channel 1 broadcast segment 2, channel 2 broadcast segment 2, channel 3 broadcast segment 2, channel 1 broadcast segment 3, channel 2 broadcast segment 3, channel 3 broadcast segment 3, … …, channel 1 broadcast segment n, channel 2 broadcast segment n, channel 3 broadcast segment n. Neighboring base stations that transmit the same broadcast channel at different power levels using different carriers may be intentionally offset in timing to allow the wireless terminal to receive and process the same information from two or more sources. For example, when a first base station using carrier C1 begins transmitting channel 3 segment 1, a second base station may begin transmitting channel 1 segment 1 at approximately the time within a number of OFDM symbol transmission time intervals, e.g., 2, 3, 10, or more.

[0064] Fig. 11 is a flow chart 1100 of an exemplary method of operating a wireless device to receive downlink broadcast signal transmissions from a plurality of neighboring base stations, wherein each base station transmits the same information using a different carrier frequency. An exemplary wireless terminal may have a single RF receiver chain. Operation begins in step 1101, where a WT, such as the exemplary MN 918 of fig. 9, is powered on and initialized. Operation proceeds from step 1101 to step 1102 and step 1104. In step 1102, the WT is operated to periodically check for a carrier signal. For example, beacon signals may be monitored, received and evaluated, and an identified first carrier corresponding to a first base station and an identified second carrier corresponding to a carrier of a neighboring base station, the identified second carrier carrying the same broadcast information as the identified first carrier but with a time offset. The first carrier may be, for example, carrier C1 corresponding to BS a 902 of fig. 9, and the second carrier may be carrier C3 corresponding to BS B904 of fig. 9.

[0065] In step 1104, the WT is operated to receive downlink broadcast signals on a first carrier, such as signals from BS a using carrier C1. Next, in step 1106, the wireless terminal is operated to store a copy of the received signal. The WT is then operated to attempt to decode the received signal in step 1108. In step 1100, if the decoding is successful, operation continues back to step 1104 for reception of other signals on the same carrier. This may be the case, for example, if the WT has sufficient channel quality with respect to BS a using carrier C1. However, if the decoding is unsuccessful, operation proceeds from step 1110 to step 1112, where the wireless terminal is operated to change its receiver to a second carrier, such as carrier C3, which corresponds to BS B downlink signaling.

[0066] The wireless terminal is then operated to receive a downlink broadcast signal transmission on a second carrier in step 1114. In step 1116, the wireless terminal is operated to store a copy of the received signal from step 1114. In step 1118, the wireless terminal attempts to decode the received signal. If the decoding is successful, operation proceeds from step 1120 back to step 1114 for receiving and processing of other signal transmissions using the second carrier; however, if the decode was unsuccessful, operation proceeds from step 1120 to step 1122.

[0067] In step 1122, the wireless terminal is operated to combine stored copies of the received signal representing the same broadcast signal user information transmitted from the first and second base stations via the first and second carriers, e.g., the signals stored in steps 1106 and 1116. Operation proceeds from step 1122 to step 1124. In step 1124, the wireless terminal is operated to attempt to decode the combined received signal. In step 1126, the wireless terminal is operated to designate first and second carriers. Operation proceeds from step 1126 to step 1104 for receiving and processing other downlink broadcast signal transmissions.

[0068] In some embodiments, a mobile node, such as a mobile node located at the edge of three or more cells, may hop between different carriers associated with each different base station, each carrier transmitting the same digital broadcast information, such as video bits, with the same segments from the three different base stations, wherein the same segments are transmitted separated at different times with sufficient timing to facilitate the reception and processing of signals from the three base stations by individual wireless terminals. In some embodiments, the signals from three base stations may be stored and combined to recover information that would otherwise not be recoverable using only the signals from one or two base stations.

[0069] In some embodiments, mobile nodes at the edge of three or more cells may hop between different carriers associated with different base stations, and individual base stations may transmit the same digital broadcast video information bits with the same segments from different base stations, wherein the same segments are transmitted separated at different times with sufficient timing to facilitate that individual wireless terminals may receive and process signals from different base stations. In some embodiments, signals from three or more base stations may be stored and combined to recover information that would otherwise not be recoverable using only signals from one or two base stations.

[0070] In some embodiments, information to be transmitted in the downlink segment is encapsulated and transmitted on different carriers taking into account the buffer capacity of the WT and the time required to switch between carriers. For example, the same information may be transmitted with sufficient symbol transmission time separation to allow the WT to switch between carriers and receive information, while the time difference between information transmissions remains within the WT's buffer capacity. In this manner, it is possible to eliminate, reduce, and/or minimize dead time in decoding and rendering (e.g., displaying) a received program, such as a movie or other video program. In some embodiments, an assigned channel function, such as a TV guide, informs the wireless terminal when to hop between carriers for the purpose of receiving information corresponding to a particular program or broadcast.

[0071] In some embodiments, the downlink video broadcast function is similar to a TV channel. In some embodiments, video on demand capabilities are incorporated into the system. For example, via an uplink signal sent from the WT to the BS, the wireless terminal may tell the network what broadcast it wants to see.

[0072] According to various embodiments, precise synchronization between base stations is not required, and synchronization with a coarse level may be sufficient, e.g., in many cases timing synchronization sufficient to allow a WT to receive information from different BSs within a time window supported by WT buffer capacity will be sufficient. A wireless terminal may be implemented using a single RF receiver chain. However, WTs with multiple receiver chains that allow the WT to receive information from two carriers at a time may also be used without colliding with WTs with a single receiver chain. According to various embodiments, a wireless terminal may receive signals using different carriers but conveying the same information from different base stations. Different base stations intentionally time-offset the transmission of information segments having equivalent information content to allow the WT to switch between multiple base stations as needed to receive the same information from multiple base stations.

[0073] Fig. 12 illustrates an exemplary system 1200 that includes a plurality of base stations including BS a1202 and wireless terminals such as mobile nodes MN 11210, MN 21212, MN 31214. A base station using multiple carriers with different intensity levels may transmit different broadcast information, such as video, on each different carrier. Table 1216 illustrates that for exemplary base station 1202, carrier 1 corresponds to low-quality video, carrier 2 corresponds to medium-quality video, and carrier 3 corresponds to high-quality video. The exemplary base station a1202 supports downlink signaling using three carriers (C1, C2, C3), three carriers (C1, C2, C3) at (high, medium, low) power levels, respectively, as indicated by circles (1204, 1206, 1208). For example, the lowest quality or lowest resolution information bit may be transmitted using the strongest carrier, such as C1. Thus, each WT (MN 11210, MN 21212, MN 31214) in the system can receive low quality video. Carrier 2 may carry information bits that, when combined with information bits extracted from the carrier 1 signal, allow the medium quality video signal to be displayed to a user. Carrier 2 therefore carries a video signal known as the enhancement layer. Alternatively, carrier 2 may carry information bits that when used alone provide medium quality video. In this example, MN 21212 and MN 31214 may receive the carrier 2 signal. MN 21212 can view medium quality video images. Carrier 3 may carry information bits that, when combined with information bits extracted from the carrier 1 and carrier 2 signals, allow high quality video signals to be displayed to a user. Alternatively, carrier 3 may carry information bits that when used alone provide high quality video. In this example, MN 31214 may receive the carrier 3 signal. The MN 31214 can view high-quality video images. Thus, the quality of the received image may be a function of how close the mobile station is to the base station.

[0074] In some embodiments, the base station may transmit specific location information. For example, the BS may transmit specific location information for each broadcast area, such as a circle corresponding to a specific transmission power level. Thus, in the embodiment of fig. 12, BS 1202 may transmit information about restaurants, stores, or other businesses within each torus using a particular carrier frequency corresponding to that torus, and in some implementations this is true. For example, the base station 1202 may transmit the location of the restaurant in the innermost torus on carrier C3, the location of the restaurant in the intermediate torus on carrier C2, and the location of the restaurant in the outermost torus on carrier C1. For example, a mobile station within the innermost ring decodes the information transmitted on carrier C3 and therefore finds a restaurant within its ring.

[0075] A mobile station located very close to the base station may receive information transmitted on the weakest carrier, but a mobile station located very far from the base station may not be able to receive and/or decode the signal. In some embodiments, a decoding failure may determine to hop to a different carrier. Frequency hopping to a different carrier may also occur if the mobile station determines that it wants to receive finer quality resolution information. The specific location information may rank the carriers from weakest to strongest.

[0076] In some embodiments, the BS may select when and whether to send higher quality resolution information.

[0077] The various methods and apparatus may be used without reducing the pitch interval or using a long cyclic prefix, which may be as required in a system.

[0078] Fig. 13 illustrates an exemplary base station 1300. Base station 1300 may be used as one of the base stations shown in, for example, fig. 6, 9, or 12. The base station 1300 includes antennas 203, 205 and receiver transmitter circuits 202, 204. The transmitter circuitry supports a plurality of different carrier frequencies such as C1, C2, C3. The receiver circuitry 202 includes a decoder 233 and the transmitter circuitry 204 includes an encoder/packetizer 235. A video-on-demand request may be received from a wireless terminal via the receiver circuit 202. The circuits 202, 204 are connected to an I/O interface 208, a processor (e.g., CPU)206, and a memory 210 by a bus 230. I/O interface 208 connects base station 1300 to the internet and/or other nodes, such as neighboring base stations, with which base station 1300 can maintain coarse timing synchronization. As noted above, timing synchronization between base stations need not be, and typically is not, on the order of the cyclic prefix duration, and in many cases, the base stations are not synchronized to the duration of the cyclic prefix, or even to several OFDM symbol transmission time periods. The synchronization may be measured in fractions of a second and, in some cases, not even synchronized to one second with neighboring base stations. The memory 210 includes routines that, when executed by the processor 206, control the base station 1300 to operate in accordance with the various embodiments. The memory includes communications routines 223 for controlling the base station 1300 to perform various communications operations including transmitting information signals such as video programs, radio broadcast programs, multicast information, etc., on multiple carrier frequencies. The memory 210 also includes a base station control routine 225 for controlling the base station 1300 to implement the steps of the method. The base station control routines 225 include a scheduling module 226 that controls transmission scheduling and/or communication resource allocation and schedules information transmissions in a manner that is coarsely aligned with transmissions of neighboring base stations having the same information, but intentionally transmits the same information from different base stations at different times. Thus, the module 226 may act as a scheduler. Memory 210 also includes information used by communication routines 223 and control routines 225. The information 212 comprises program items 213, 213' corresponding to each program, such as a video or audio program, to be transmitted. The program item may include program information, such as video data to be transmitted, and optionally information about time, such as the date and time the program is to be transmitted.

[0079] Fig. 14 illustrates an exemplary wireless terminal such as mobile node 1400. The mobile node 1400 may be used as a Mobile Terminal (MT), and the mobile node 1400 may receive, decode and output program and/or multicast information received from a base station. Wireless terminal 1400 includes a receiver module 302, a transmitter module 304, a processor 306, a display 307, an audio output device 308, and a memory 310 coupled together via a bus 309, wherein the various components can exchange data and information with one another over the bus 309. For example, the program may be a television program or an audio program. The mobile node 1400 includes receiver and transmitter antennas 303, 305 coupled to the receiver and transmitter circuits 302, 304, respectively. The receiver circuitry 302 includes a decoder 333 and the transmitter circuitry 304 includes an encoder/packetizer 335. Processor 306 causes mobile node 1400 to operate under the control of one or more routines stored in memory 310. This includes, for example, receiving program information on different carriers, switching between carriers, combining program information received from different carriers, and displaying or outputting decoded program information. To control the operation of mobile node 1400, memory 310 includes communications routines 323, and mobile node control routines 325. Mobile node control routines 325 are responsible for controlling the operation of mobile node 1400. Memory 310 also includes user/device/session/resource information 312 that may be accessed and used to implement methods and/or data structures. Memory 310 also includes a received program buffer 327 for storing received program information, a video decoder 329 for decoding received compressed video information, such as an MPEG-4 video signal, and an audio decoder 331 for decoding received compressed audio signals, and a program playback routine 333 for controlling the display and/or audio output of received decoded programs.

[0080] Fig. 15 is a diagram of an exemplary base station 1500. Exemplary BS 1500 may be any of the exemplary base stations of fig. 6, 9, or 12. The exemplary base station 1500 includes a receiver 1502, a transmitter 1504, a processor 1506, a clock module 1508, an I/O interface 1510, and a memory 1512 coupled together via a bus 1514 over which the various components can exchange data and information with one another. In some embodiments, base station 1500 is a sectorized base station supporting multiple sectors, and base station 1500 includes additional transmitters and/or receivers, such as separate transmitter/receiver pairs for each sector. For example, in an M-sector embodiment of BS 1500, receiver 1502 and transmitter 1504 can correspond to sector 1, while receiver 1516 and transmitter 1518 correspond to sector M. A receiver 1516 and a transmitter 1518 may also be coupled to bus 1514. Each sector may support multiple carriers. For example, in some embodiments, each sector may support simultaneous transmissions using three different downlink carriers, where each of the three downlink carriers is associated with one non-overlapping pitch block.

[0081] A receiver 1502, such as a multicarrier receiver associated with sector 1, is coupled to receive antennas 1520 and receives uplink signals from wireless terminals via the receive antennas 1520. The receiver 1502 includes a decoder 1522 that decodes the received uplink signal. A receiver 1516, such as a multicarrier receiver, associated with sector M is coupled to receive antenna 1524 and receives uplink signals from wireless terminals via receive antenna 1524. Receiver 1516 includes a decoder 1526 that decodes the received uplink signal.

[0082] A transmitter 1504, such as a multicarrier transmitter, associated with sector 1 is coupled to the transmit antenna 1528 for transmitting downlink signals, such as including broadcast signals, to the wireless terminals via the transmit antenna 1528. The transmitter 1504 includes an encoder 1530 that encodes downlink data/information prior to transmission. A transmitter 1518, such as a multicarrier transmitter, associated with sector M is coupled to a transmit antenna 1532 for transmitting downlink signals, such as including broadcast signals, to wireless terminals via the transmit antenna 1532. The transmitter 1518 includes an encoder 1534 that encodes downlink data/information prior to transmission.

[0083] Memory 1512 includes routines 1536 and data/information 1538. The processor 1506, such as a CPU, executes the routines 1536 and uses the data/information 1538 to control the operation of the base station 1500 and implement the methods. I/O interface 1510 connects BS 1500 to other network nodes such as other base stations, routers, AAA servers, content providing servers, and/or the internet. I/O interface 1510 connects base station 1500 to a backhaul network that provides WTs using base station 1500 as their network point of attachment with other nodes and/or information resources outside of the base station's cellular coverage area. In some embodiments, the service providing node may transmit an information program, such as information representing a digital video broadcast stream, to the BS 1500 through the I/O interface 1510, broadcasting the program in a segmented form through a plurality of base stations, such as neighboring base stations.

[0084] Routines 1536 include communications routines 1540 and base station control routines 1542. Communications routines 1540 implement the various communications protocols used by BS 1500. Base station control routines 1542 include scheduler module 1544, carrier/sector power level control module 1546, program segment timing transmission control module 1548, and timing synchronization module 1550.

[0085] Scheduler module 1544 schedules WT users to uplink and downlink communications segments. Some of the communication channel segments may be traffic channel segments scheduled to one or more users. Some downlink communication segments may be broadcast segments that include information programs. In some embodiments, at least some broadcast programming may be made available to any subscribing wireless terminal user within the coverage area. In some embodiments, at least some broadcast programs may be made available to a selected group of subscribing wireless terminal users, such as a particular multicast group, within the coverage area via encryption and selective key distribution. The scheduler module 1544 includes a program segment/carrier/sector/communication segment coordination module 1552. Each program to be broadcast is associated with at least one carrier frequency and one sector. Each program to be broadcast on the downlink may be subdivided into a plurality of program segments, and module 1552 may associate each program segment with one or more carrier frequencies, one or more sectors, and one or more communication segments within the downlink timing and frequency structure. In some embodiments, a program segment is transmitted for a given sector and a given carrier frequency using multiple communication segments. Encoding, such as encoding of blocks of program information, may be performed on a program segment basis and/or a communication segment basis.

[0086] The carrier/sector power level control module 1546 controls the downlink transmission power level of the transmitter (1504, 1518) associated with each carrier supported by the transmitter (1504, 1518). In some embodiments, at least some sectors of BS 1500 support multiple power levels, with each different carrier frequency supported by a sector being associated with a different power level, e.g., three carriers and three power levels. Neighboring sectors from the same cell or different cells using the same carrier may have different power levels associated with the same carrier.

[0087] Program segment timing transmission control module 1548 controls the operation of BS 1500 such that broadcast program segments maintain a timing sequence throughout a coordinated timing sequence constructed between multiple neighboring base stations, e.g., maintain offsets within segment sequences corresponding to programs transmitted by two neighboring base stations, to potentially be received by the same MN at different times.

[0088] Timing synchronization module 1550 operates in conjunction with clock module 1508 to maintain timing synchronization for BS 1500. Timing synchronization module 1550 includes a base station/base station coarse synchronization module 1554 and a BS synchronization module 1556. BS/BS coarse synchronization module 1554 is operated to maintain approximate synchronization between neighboring base stations, e.g., with stability over several OFDM symbol transmission time intervals, such as 2, 3, 10, or more. In some embodiments, the same program segment broadcast from neighboring base stations may be intentionally offset so that WTs with a single RF receiver stage may switch between different carrier frequencies and receive two transmissions of the same segment using different carrier frequencies. BS/BS coarse synchronization module 1554 maintains inter-base station tolerances, such as those associated with program segment transmission, so that broadcast signals from multiple neighboring base stations can be used. Base station synchronization module 1556 maintains a high level of synchronization, such as less than one OFDM symbol transmission time interval, between signal transmissions of various sectors of a base station such that OFDM symbols are arranged with respect to different carriers within the same sector of BS 1500 and/or arranged with respect to different sectors.

[0089] Data/information 1538 includes system timing/frequency structure information 1558, such as for an OFDM system, base station/sector identification information 1560, wireless terminal information 1562, user/device/session/resource information 1564, program segment timing information 1566, and multiple sets of information corresponding to each carrier/sector combination for an attachment point that BS 1500 may use for broadcast of downlink signals (carrier 1 sector 1 data/information 1568, carrier N sector M data/information 1570). In some embodiments, one or more sets of multi-resolution video program information (multi-resolution video programs 11572, … …, multi-resolution video program N1574) are included. In some embodiments, multiple sets of geo-location based program information 1576 are included.

[0090] For example, system timing and frequency structure information 1558 includes uplink and downlink communication segment structures, uplink and downlink carrier frequencies, bandwidths, pitch blocks, pitch intervals, sector information, uplink and downlink pitch hopping sequences, OFDM symbol transmission timing intervals, grouping OFDM symbol transmission timing intervals into time slots, superslots, beacon slots, superslots, etc., timing control margin information for different sectors of a BS, timing control margin information for different base stations such as neighboring base stations, etc. Base station/sector identification information 1560 includes a base station identifier and/or a sector identifier. In some embodiments, BS/sector ID information 1560 is communicated to WTs via the downlink using periodically broadcast beacon and/or pilot signals. Wireless terminal information 1562 includes information about WTs that may have registered, e.g., a sector/carrier frequency combination, with a network attachment point base station. WT information 1562 may include a WT active user ID, such as temporarily assigned by BS 1500 for the WT that seeks to transmit uplink signals, such as part of a communication session, to base station 1500. In some embodiments, at least some WTs receiving downlink broadcast signals, such as downlink broadcast programs, do not need or do not have themselves identified to the base station and do not obtain an active user ID. For example, at least some WTs may subscribe to receive some downlink broadcast programs from a service provider affiliated with BS 1500, may be provided with decoding information that is valid for a given time interval, and may then receive and decode downlink broadcast programs. In some embodiments, for example, at least some WTs need to register with BS 1500 prior to receiving downlink broadcast program information in order to receive temporarily valid decoding and/or descrambling information and/or for billing purposes such as billing. Program segment timing information 1566 includes information used to time the transmission of each program segment to be broadcast by the base station. For example, two neighboring base stations may broadcast the same program segment, but may intentionally offset the broadcast timing of different BSs 1500 in the system. Program segment timing information 1566 also includes information associating each program segment with one or more communication segments in the base station's downlink timing and frequency structure.

[0091] Program 11578 includes a plurality of segments (segment 11551, segment N1553); program N1580 also includes a plurality of segments (segment 11555, segment N1557).

[0092] Carrier 1 sector 1 data/information 1568 includes frequency information 1586, pitch block information 1587, power level information 1588, program related information 1589, data rate 1590, geographic coverage area information 1591, and in some embodiments resolution level information 1592; frequency information 1586 such as, among other things, the downlink carrier frequency used; gene block information 1587 such as a set of pitches associated with the carrier frequency; power level information 1588 such as high, low or medium power levels associated with the carrier and sector; program related information 1589 such as information identifying which program or programs are to be broadcast by the sector transmitter using the carrier identified by 1586; a data rate 1590, such as the information bit data rate of the program information, which is a function of the code rate, modulation scheme, and timing interval between transmitted program segments; geographic coverage area information 1591 such as information identifying the physical coverage area associated with the sector and carrier to which the broadcast program is expected to arrive; resolution level information 1592 is information associating carriers and sectors with high, low or medium level video capacity, such as in embodiments including multi-level resolution video.

[0093] The multi-level resolution video program 11572 includes a plurality of sets of different resolution video information segments corresponding to program 1 ((high resolution segments 11593, … …, high resolution segment N1594), (medium resolution segments 11595, … …, medium resolution segment N1596), (low resolution segments 11597, … …, low resolution segment N1598)). Multi-level video program N1574 includes a plurality of different resolution video information segment sets ((high resolution segments 11599, … …, high resolution segment N1501), (medium resolution segments 11503, … …, medium resolution segment N1505), (low resolution segments 11507, … …, low resolution segment N1509)) corresponding to program N.

[0094] The geographical based program information 1576 includes a plurality of set of specific region segments ((region 1 segment 11511, … …, region 1 segment N1513), (region N segment 11515, … …, region N segment N1517)). The different sets of program segments for a particular area may be customized to provide a geographic area such as a restaurant, theater, store, parking lot, emergency facility, etc. within that area. In some embodiments, at least some of the geography-based programming sets for an area include advertisements related to the area. In some embodiments, geographic-based programming may be provided as a service to wireless terminal users who desire to find restaurants. In some embodiments, geographic-based programs may be mixed with program collections, such as program collection 11568, which may provide video streams such as movies, television shows, internet broadcasts, and the like; and may interleave geographic-based information (e.g., zone 1 segment 11511, zone 1 segment N) as at least some of the commercials that are directed to WT users.

[0095] Fig. 16 illustrates an exemplary wireless terminal 1600, such as a mobile node. Exemplary WT1600 may be any exemplary WT used in the exemplary systems of fig. 6, 9 or 12. The wireless terminal 1600 is capable of receiving, decoding, and outputting programming and/or multicast information received from a base station. For example, the program may be a television program or an audio program. A wireless terminal 1600, such as a mobile node, includes receiver and transmitter antennas 1603, 1605, which are connected to receiver and transmitter modules 1602, 1604, respectively, 1603 and 1605. Receiver module 1602 includes a decoder 1633, and transmitter module 1604 includes an encoder 1635. The wireless terminal 1600 also includes a processor 1606, user I/O devices 1608, and memory 1610.

[0096] The user I/O devices 1608 include a user input device 1601, a display 1607, and an audio output device 1609; among other things, user input devices 1601 such as a keypad, keyboard, touch screen, camera, microphone, etc.; a display 1607 such as an LCD display, LEDs, indicator lights, CRT, flat panel display, image projection device, video output feed line/interface, or the like; an audio output device 1609 such as a speaker, alarm, audio output feed line/interface, or the like. The various components 1602, 1604, 1606, 1608, and 1610 are connected together via a bus 1605, where the various components can exchange data/information with one another over the bus 1605. The wireless terminal 1600, such as a mobile node, is operated by the processor 1606, such as a CPU, under the control of one or more routines stored in the memory 1610. For example, it includes: receiving program information on different carriers, switching between carriers, combining program information received from different carriers, and displaying or outputting decoded program information. To control wireless terminal 1600, such as a mobile node, operations memory 1610 includes communications routines 1623 and wireless terminal control routines 1625 that execute the communications protocols used by WT 1600.

[0097] The wireless terminal control routines 1625 are responsible for ensuring that the wireless terminal 1600, such as a mobile node, is operational and performing the steps described with respect to the operation of the wireless terminal. Memory 1610 also includes user/device/session/resource information 1627 that can be accessed and used to implement the methods and/or data structures.

[0098] Wireless terminal control routines 1625 include a receiver control module 1629, a transmitter control module 1631, an I/O device control module 1633, a carrier signal monitor/estimation module 1635, a carrier switch module 1637, a segment merge module 1639, a received program decoder module 1641, and a program rebroadcast module 1643. Received program decoder module 1641 includes an audio decoder module 1645, a video decoder module 1647, and a decode estimation module 1649. In some embodiments, video decoder module 1647 includes a multi-level resolution module 1651. Receiver control module 1629, operating in conjunction with other modules such as modules 1635, 1637, 1639 and/or 1641, controls the operation of receiver 1602 and decoder 1633 to receive and process downlink signals from a BS, e.g., including downlink broadcast signals including information programs transmitted in segments. Transmitter control module 1631 controls the operation of transmitter 1604 and encoder 1635 in sending uplink signal transmissions to the BS. I/O device control module 1633 controls the operation of user I/O device 1608 and may operate in conjunction with program playback module 1643. Carrier signal monitoring/estimation module 1635 may monitor the strength and/or quality of the received carrier signal, e.g., measure beacon strength level, interference level, decoding success rate, etc. Carrier switching module 1637 uses the results from carrier signal monitoring/estimation module 1635 and/or program segment timing information to determine when and whether to switch between carriers so that program segments from one or more base stations can be received. To recover the information, segment combining module 1639 combines segments, e.g., segments from two different neighboring base stations that use two different carrier frequencies to convey at least some of the same information content. The segment merging module 1639 may also merge different segments, e.g., carrying different increments of information, to achieve higher video levels. Segment merge module 1639 may also merge multiple received and successfully decoded segments corresponding to a program into a merged program segment information set, such as information 1657.

[0099] Video decoder module 1647 controls video decoding and audio decoder module 1645 controls audio decoding. When executed, the multi-level resolution module 1651 controls operations relating to multi-level video selection, decoding, merging, processing, and so forth. The decode evaluation module 1649 determines whether the decoding, such as a single program segment decoding or a combined decoding of joint segments from the base station, was successful. In some embodiments, the result of the decode estimate module 1649 is used to trigger the following: switching to another carrier from another base station, attempting recovery of a corresponding segment from a neighboring base station, and/or failing to successfully recover a single segment, combining multiple corresponding segments to attempt recovery.

[00100] The data/information included in memory 1610 includes received program buffer 1653 corresponding to the first carrier, processed (decoded) program buffer 1655 corresponding to the first carrier, combined program segment 1657 corresponding to the received program, currently selected downlink carrier information 1659, decoded audio and/or video 1661 selected for stream processing and/or playback, current BS/sector ID information 1665, system timing/frequency structure information 1667, such as an OFDM system, and program directory information 1669.

[00101] In some embodiments, multiple received program buffers are included, e.g., received program buffer 1617 corresponding to the nth carrier. In some embodiments, a merged program buffer 1673 is included that corresponds to a multiple carrier information merge. In some embodiments, multiple processed (decoded) program buffers are included, e.g., processed (decoded) program buffer 1675 corresponding to the nth carrier. In some embodiments, a merge process (decode) program buffer 1677 is included.

[00102] In some embodiments, for example, where the base station broadcast information is directed to a particular geographic area, including geographic-based receipt information 1679 such as restaurants, hotels, etc. In some embodiments, for example, the embodiments support multi-level video broadcasting, including video resolution level information 1681. Video resolution level information 1681 includes information identifying a current video level capacity that is currently being received and displayed.

[00103] Received program buffers (1653, 1671, 1673) are used to store received program information. Video decoder module 1647 is used to decode received compressed video information, such as an MPEG-4 video signal, and audio decoder module 1645 is used to decode received compressed audio signals. Program playback module 1643 is used to control the display and/or audio output of received decoded programs.

[00104] Fig. 17 is a diagram of an exemplary system 1700. System 1700 includes a plurality of base stations (BS a 1702, BS B1704) and a plurality of mobile nodes (MN 11718, MN 21720, MN N1722). The base station (1702, 1704) may be any of the exemplary BSs of fig. 13 or 15, and the MN (1718, 1720, 1722) may be any of the exemplary wireless terminals of fig. 14 or 16. BS a 1702 and BS B1704 each support three carriers at different power levels, and the order of power levels is different for two neighboring base stations. Fig. 17 illustrates that selected power levels associated with different carriers of neighboring base stations provide overlapping coverage from neighboring base stations, e.g., where a wireless terminal may be expected to be able to receive and decode signals from neighboring base stations. A multi-carrier, multi-power level embodiment such as that shown in fig. 17 is advantageous in implementing the downlink broadcast method.

[00105] BS a 1702 uses carrier C1 at high transmit power levels with coverage areas represented by large circles 1706; BS a 1702 uses carrier C2 at a medium transmit power level with a coverage area represented by middle circle 1708; BS a 1702 uses carrier C3 at low transmit power levels with a coverage area represented by small circle 1710. BS B1704 uses carrier C3 at high transmit power levels with a coverage area represented by large circle 1712; BS B1704 uses carrier C1 at a medium transmit power level with a coverage area represented by middle circle 1714; BS B1704 uses carrier C2 at a low transmit power level with a coverage area represented by small circle 1716. Exemplary MN 11718 is within a coverage area where it may receive and recover: the signal is transmitted from BS a 1702 using carrier C1 and from BS B1704 using carrier C3. Exemplary MN 21720 is in a coverage area where it may receive and recover signals: the signal is transmitted from BS a 1702 using carrier C1 and from BS B1704 using any one of carriers C3, C1 and C2. Exemplary MN N1722 is within a coverage area where it may be possible to receive and recover: the signal is transmitted from BS a 1702 using any one of carriers C1 and C2, and from BS B1704 using any one of carriers C3 and C1.

[00106] In some embodiments, segments, such as program segments, carry the same information that is transmitted by two base stations at different times. In some embodiments, one base station transmits segment a carrying information (a0, a1) and another base station, such as a neighboring base station, transmits segment B carrying information (a0, a 2). In this exemplary embodiment, the information carried by segments a and B is not exactly the same. However, it is important that the same information set is repeated in both segments, in which case the same information set is a 0.

[00107] In some embodiments, the timing offset of the first base station, such as BS a transmitting segments within carrier C1 and BS B transmitting segments within carrier C3, is fixed, e.g., similar to the relative power relationship between carriers C1 and C3. In this way, a wireless terminal, such as a mobile node, knows when to switch to, for example, which carrier to decode the segment.

[00108]Fig. 18 is a diagram of an exemplary system 1800. The system 1800 includes a plurality of base stations (first base station 1802, second base station 1804, third base station 1806) and a plurality of mobile nodes (MN 11808, MN 21810, MN N1812). The base station (1802, 1804, 1806) may be any of the example BSs of fig. 13 or fig. 15, and the MN (1808, 1810, 1812) may be any of the example wireless terminals of fig. 14 or fig. 16. The base stations (1802, 1804, 1806) each support three sectors and three carriers within each sector, the three carriers being at different power levels within each sector, and the order of power levels being different with respect to two adjacent base stations. The power level is represented by the relative size of the circle surrounding the base station; the line shapes of the circled portions in a given sector represent the corresponding carriers. Table 1832 shows: dotted line 1834 is used to represent carrier f having a bandwidth of 1.25MHz₁And dotted/dotted line 1836 is used to represent carrier f having a bandwidth of 1.25MHz₂Dashed line 1838 is used to indicate carrier f having a bandwidth of 1.25MHz₃. The overlap area between adjacent sectors and cells occurs according to the frequency and power level relationship selected and used. The multi-carrier, multi-power level, multi-sector embodiment shown in fig. 18 is beneficial for the implementation of the downlink broadcast method.

[00109] The first base station 1802 supports sector a 1814, sector B1816, sector C1818. The second base station 1804 supports sector a 1820, sector B1822, sector C1824. The third base station 1806 supports sector a 1826, sector B1828, sector C1830.

[00110]For sector A1814, carrier (f) of first base station 1802₁，f₂，f₃) The (high, medium, low) transmit power levels are used respectively. For sector B1816 of the first base station 1802, carrier (f)₂，f₃，f₁) The (high, medium, low) transmit power levels are used respectively. For sector C1818 of the first base station 1802, carrier (f)₃，f₁，f₂) The (high, medium, low) transmit power levels are used respectively.

[00111]For sector A1820 of the second base station 1804, carrier (f)₁，f₂，f₃) The (high, medium, low) transmit power levels are used respectively. For sector B1822 of the second base station 1804, carrier (f)₂，f₃，f₁) The (high, medium, low) transmit power levels are used respectively. For sector C1824 of the second base station 1804, carrier (f)₃，f₁，f₂) The (high, medium, low) transmit power levels are used respectively.

[00112]For sector A1826 of the third base station 1806, carrier (f)₁，f₂，f₃) The (high, medium, low) transmit power levels are used respectively. For sector B1828 of the third base station 1806, carrier (f)₂，f₃，f₁) The (high, medium, low) transmit power levels are used respectively. For sector C1830, carrier (f) of the third base station 1806₃，f₁，f₂) The (high, medium, low) transmit power levels are used respectively.

[00113]Exemplary MN 11808 is located in an area where it is likely that carrier f may be used for a point of attachment from a first base station sector C₃The transmitted signal is received and recovered. Exemplary MN 11808 is located in an area where it is likely that carrier f may be used for a point of attachment from a third base station sector a₁The transmitted signal is carried outReceiving and recovering.

[00114]Exemplary MN 21810 is located in an area within which it is likely that carrier f may be used for attachment point from second base station sector B₂Transmitted signal and use of carrier f from second base station sector C attachment point₃The transmitted signal is received and recovered. Exemplary MN 21810 is located in an area where it is likely that carrier f may be used for attachment points from a third base station sector a₁The transmitted signal is received and recovered.

[00115]Exemplary MN N1812 is located in an area where it is likely that carrier f can be used for the point of attachment from the first base station sector C₃The transmitted signal is received and recovered. Exemplary MN N1812 is located in an area where it is likely that carrier f can be used for a point of attachment from a second base station sector B₂The transmitted signal is received and recovered.

[00116] Fig. 19 is a flow chart 1900 of an exemplary communication method. Operation begins in step 1902 with powering and initializing a base station or base stations in a system including first and second base station transmitters. For example, an exemplary system may be a spread spectrum OFDM wireless communication system that includes a plurality of base station transmitters that may broadcast downlink OFDM signals and a plurality of wireless terminals that may receive and process the OFDM signals. The first and second base station transmitters may be timing controlled such that there is a coarse level of timing synchronization between the two base station transmitters, but no timing control is required to obtain and maintain a high level of timing synchronization between the two base stations. For example, if the first and second base station transmitters use OFDM signals and the first and second base station transmitters correspond to different cells, then the timing synchronization between the first and second base station transmitters is not controlled to be within the cyclic prefix duration. In step 1902, a communication program may be communicated to a base station or a plurality of stations including first and second base station transmitters, for example, via a backhaul network, wherein the program originates from a content provider service node. The backhaul network may include wired and/or wireless links such as fiber optic cables, microwave links, and the like. Alternatively, in step 1902, the initial portion of the program may have been provided to the base station or base stations including the first and second base station transmitters, while other portions are provided at a subsequent time, for example, when the first and second base station transmitters are in the process of broadcasting a previously received portion on a downlink radio channel that a wireless terminal, such as a mobile node, may be receiving using.

[00117] Operation proceeds from start step 1902 to steps 1904 and 1906. In step 1904, the first base station transmitter may be operated to transmit a program segment corresponding to the first program. In step 1906, a second base station transmitter located adjacent to the first base station transmitter may be operated to transmit the same program segments of the first program as the first base station transmitter, but the first and second base station transmitters transmit segments having the same information content at different times.

[00118] In some embodiments, the first and second base station transmitters are located in adjacent single sector cells. In other embodiments, the first and second base station transmitters are sector transmitters located in neighboring sectors, wherein the communication method is used in a system having a multi-sector cell and the neighboring sectors are sectors of the same cell or sectors of neighboring multi-sector cells.

[00119] In various embodiments, a first base station transmitter transmits a program segment corresponding to a first program using a first carrier and a second base station transmitter transmits a program segment corresponding to the first program using a second carrier, wherein the second carrier has a different frequency than the first carrier. In some such embodiments, a first base station transmitter transmits program segments corresponding to a first program at a first transmission power level and a second base station transmitter transmits program segments corresponding to the first program at a second transmission power level, wherein the second transmission power level is different from the first transmission power level.

[00120] In some embodiments, operating the second base station transmitter includes controlling different times according to a timing offset, such as a fixed timing offset, wherein the second base station transmitter is located adjacent to the first base station transmitter so as to transmit the same program segment of the first program as the first base station but the first and second base station transmitters transmit segments having the same information content at different times; the fixed time offsets have respective timing offset tolerances maintained by the second base station transmitter. In some such embodiments, the information program segments are transmitted using OFDM symbols transmitted with a cyclic prefix, and the first and second base station transmitters transmit timing offsets between program segments having the same information content greater than the duration of the cyclic prefix.

[00121] In some OFDM embodiments, the first and second base station transmitters are not synchronized within a cyclic prefix duration, and a transmission offset between program segments transmitted by the first and second base stations having the same information content exceeds a duration of a symbol transmission time period, wherein the symbol transmission time period includes a time for transmitting one OFDM symbol and a corresponding cyclic prefix. In some such embodiments, the time offset between transmission of a program segment by a first base station transmitter and transmission of a program segment having the same program content by a second base station transmitter is at least equal to the amount of time used to transmit the program segment, e.g., equal to the amount of time used by the first and second transmitters to transmit the program segment, equal to the amount of time used by the second transmitter to transmit the program segment, or equal to the amount of time used by the first transmitter to transmit the program segment.

[00122] In various embodiments, the first base station transmitter does not transmit program segments corresponding to the first program when the second base station transmitter transmits program segments corresponding to the first program, wherein the first and second base station transmitters transmit program segments corresponding to the first program in an interleaved manner. In some such embodiments, the first and second base station transmitters transmit interleaved program segments on a periodic basis with a transmission time between program segments corresponding to the first program of less than 5 seconds.

[00123] In some embodiments, the first and second base station transmitters each transmit using multiple carrier frequencies, and adjacent base station transmitters use different transmission power levels for the same carrier frequency. In some such embodiments, each carrier frequency corresponds to a different OFDM tone block, the tones of the different OFDM tone blocks being non-overlapping in frequency.

[00124] In some embodiments, the first and second base station transmitters each transmit using three carrier frequencies; adjacent base station transmitters use different transmission power levels for the same carrier frequency; each carrier frequency corresponds to a different OFDM tone block; the pitches of different OFDM pitch blocks are non-overlapping in frequency and for a given transmitter, their three pitch blocks are consecutive in frequency.

[00125] Fig. 20 is a flow diagram 2000 of an exemplary method of operating a base station in accordance with various embodiments. The method starts in step 2002 and in step 2002 the base station is powered up and initialized. Operation proceeds from start step 2002 to step 2004. In step 2004, the base station may be operated to transmit program information using a plurality of carriers, signals corresponding to different carriers including a first carrier and a second carrier being transmitted at different power levels. In some embodiments, the plurality of carriers includes at least three different carriers, and step 2004 includes transmitting some of the same program information on each of the three different carriers but at different power levels.

[00126] Step 2004 includes sub-steps 2006 and 2008. In sub-step 2006, the base station is operated to transmit program information on a first carrier, wherein the first carrier is transmitted at a first power level. In sub-step 2008, the base station is operated to transmit program information on a second carrier, wherein the second carrier is transmitted at a second power level different from the first power level.

[00127] In various embodiments, such as sub-step 2008, transmitting the program information on the second carrier includes transmitting the program information at a second transmit information data rate that is different from the first transmit information data rate at which the program information is transmitted on the first carrier. For example, in some such embodiments, the first power level is lower than the second power level, and the first information data rate is higher than the second transmitted information data rate.

[00128] In various embodiments, the program information comprises a video program, and transmitting the program information on the first carrier comprises transmitting at least a portion of the video program at a first video resolution on the first carrier, such as sub-step 2006. In some such embodiments, such as sub-step 2008, transmitting the program information on the second carrier includes transmitting the program information on the second carrier at a resolution lower than a resolution at which the program information is transmitted on the first carrier. In some embodiments, step 2004 includes transmitting at least some of the same program information on the first and second carriers but at different resolutions.

[00129] In some embodiments, transmitting program information comprises transmitting the same program information on both the first and second carriers, and transmitting additional program information on the first carrier that is not transmitted on the second carrier. In some embodiments, transmitting the program information comprises transmitting more program information on the first carrier during a certain time period than on the second carrier during the same time period.

[00130] In some embodiments, the second carrier signal covers a wider geographical area than the first carrier area, e.g., due to a higher power level associated with the second carrier, and the method further comprises: the method comprises transmitting information on traffic located within a first coverage area of a first carrier and transmitting information on traffic outside the first coverage area but within a coverage area of a second carrier using a second carrier.

[00131] In various implementations, the program information transmitted on the second carrier is basic video information, such as in sub-step 2008, and the program information transmitted on the first carrier is enhancement information, such as in sub-step 2006, which can be combined with the basic video program to provide a higher quality video presentation than is possible using only the program information transmitted on the second carrier.

[00132] In some embodiments, the program information transmitted on the second carrier is a basic program, such as in sub-step 2008, and the program information transmitted on the first carrier includes the basic program plus additional content, such as in sub-step 2006. In some such embodiments, the additional content includes at least one of: video content not included in the base program, support for additional languages not included in the base program, a text stream to be displayed with the base video content, advertisements not transmitted on the second carrier.

[00133] In some embodiments, the program information transmitted on the second carrier is a basic program, such as in sub-step 2008, and the program information transmitted on the first carrier may be combined with the program information on the second carrier to provide additional content, such as in sub-step 2006. In some such embodiments, the additional content includes at least one of: video content not included in the base program, support for additional languages not included in the base program, text streams to be displayed with the base video content, and advertisements.

[00134] Fig. 21 is a diagram of an exemplary base station 2100, such as access node 2100. The exemplary base station 2100 includes a multicarrier receiver assembly 2102, a multicarrier transmitter assembly 2104, a processor 2106, an I/O interface 2108, and a memory 2110 coupled together via a bus 2112, wherein the various components exchange data and information over the bus 2112. Memory 2110 includes routines 2124 and data/information 2126. The processor 2106, such as a CPU, executes the routines 2124 and uses the data/information 2126 in memory 2110 to control the operation of the base station 2100 and implement methods.

[00135] The I/O interfaces 2108 connect the base station 2100 to other network nodes, such as routers, other base stations, program content servers, AAA servers, routers, control nodes, core nodes, etc., and/or the internet. Thus, program information to be broadcast is received from the respective program content servers via the I/O interface 2108.

[00136] The multicarrier receiver section 2102 is connected to a receive antenna 2103 via which receive antenna 2103 the base station receives uplink signals from the wireless terminal. The multicarrier receiver component 2102 comprises a decoder 2114 for decoding at least some of the received uplink signals. In some embodiments, the received uplink signal includes a registration request signal from the wireless terminal requesting reception of the broadcast program.

[00137] The multi-carrier transmitter assembly 2104 transmits program information using at least first and second carriers under control of the transmission scheduling module 2132. In various embodiments, the multicarrier transmitter assembly 2104 transmits program information on first and second carriers at first and second transmission information data rates, respectively, and the first and second transmission data rates are different. The multi-carrier transmitter assembly 2104 is connected to a transmit antenna 2105, via which transmit antenna 2105 the base station 2100 transmits downlink signals to wireless terminals. The downlink broadcast signal includes information carrying one or more broadcast programs. In some embodiments, the multicarrier transmitter assembly 2104 includes one or more multicarrier transmitter modules 2116. For example, in some embodiments, a single base station transmitter transmits on frequencies corresponding to multiple downlink carriers, such as three downlink carriers, where each downlink carrier corresponds to one downlink OFDM tone block. In some embodiments, the multicarrier transmitter assembly 2104 includes a plurality of single carrier transmitter modules (carrier 1 transmitter modules 2118, … …, carrier N transmitter module 2120).

[00138] In an exemplary embodiment, the multi-carrier transmitter assembly 2104 includes a single three-carrier transmitter module 2116, wherein the base station 2100 corresponds to a single sector cell using three downlink carriers. In an exemplary embodiment, the multi-carrier transmitter assembly 2104 includes three single carrier transmitter modules, wherein the base station 2100 corresponds to a single sector cell using three downlink carriers.

[00139] In an exemplary embodiment, the multi-carrier transmitter assembly 2104 includes three-carrier transmitter modules 2116, wherein the base station 2100 corresponds to a three-sector cell using three downlink carriers. In an exemplary embodiment, the multi-carrier transmitter assembly 2104 includes nine single carrier transmitter modules, wherein the base station 2100 corresponds to a three sector cell using three downlink carriers.

[00140] The multicarrier transmitter assembly 2104 includes an encoder 2122 for encoding at least some of the information to be broadcast via the downlink broadcast signal. In some embodiments, the individual downlink programs are encrypted, e.g., the programs are restricted to only authorized wireless terminals to access.

[00141] Routines 2124 include communications routines 2128 and base station control routines 2130. Communications routines 2128 implement the communications protocols used by base station 2100. Communications routines 2128 also process various communications operations, such as controlling I/O interface 2108 operations to receive program content from a program content server to be broadcast.

[00142] Base station control routines 2130 include a transmission scheduling module 2132 and a carrier power level control module 2134. The transmission scheduling module 2132 schedules transmission of program information on a plurality of carriers, e.g., the first and second downlink carriers used by the multi-carrier transmitter assembly 2104. Carrier power level control module 2134 uses data/information 2126 including power level information 2144 to control the transmission power levels of the plurality of downlink carriers used by the base station 2100 to maintain the power difference between the first and second downlink carriers corresponding to the multi-carrier transmitter assembly 2104. In various embodiments, the carrier power level control module 2134 controls a first power level associated with a first downlink carrier to be lower than a second power level associated with a second downlink carrier with respect to the multicarrier transmitter assembly 2104.

[00143] Data/information 2126 includes, for example, system timing and frequency structure information 2136 for the OFDM system, base station/sector identification information 2138, wireless terminal information 2140, and user/device/session/resource information 2142. In various embodiments, the downlink channel structure includes segments such as indexed segments in a cyclic structure having at least some indexed segments allocated for conveying downlink broadcast program information. The system timing and frequency structure information 2136 includes downlink/uplink channel structure information, downlink/uplink carrier information, downlink/uplink pitch block information, downlink/uplink pitch hopping information, and the like. Base station/sector identification information 2138 includes base station cell identification information, sector identification information, and/or sector type information such as corresponding to each multicarrier transmitter element 2104. The information 2140 of the wireless terminal includes information associated with a plurality of wireless terminals using the base station 2100. In some embodiments, WT information 2140 includes registration information, security information, and/or charging information associated with the wireless terminal receiving the transmitted program. User/device/session/resource information 2142 includes user identification information, device identification information, and air link resource information associated with wireless terminals that are participating in a communication session with a peer node and/or are receiving a transmission, such as a broadcast, program. In various embodiments, the base station 2100 supports transmitted broadcasts, programs, and communication sessions that include two peer wireless terminals simultaneously. In various embodiments, at least some broadcast programs are targeted to a selected group of users, such as a multicast group with authorized access. In some embodiments, base station 2100 supports broadcast signaling but does not support communication sessions that include two peer wireless terminals.

[00144] Data/information 2126 also includes power level information 2144, resolution information 2146, program information 2148, and transmission timing schedule information 2150. Power level information 2144 includes a plurality of power level information (carrier 1 power level information 2154, … …, carrier N power level information 2156) that carrier power level control module 2134 uses to control multicarrier transmitter element 2104. In some embodiments, the power level information 2144 indicates that at least two different carriers used by the multi-carrier transmitter assembly 2104 are to be transmitted at different power levels. In some embodiments, the power level information 2144 indicates that each different carrier used by the multi-carrier transmitter assembly 2104 is to be transmitted at a different power level. Resolution information 2146 includes a plurality of resolution levels (carrier 1 resolution information 2158, … …, carrier N resolution information 2160) associated with each carrier used by multicarrier transmitter assembly 2104. For example, in some embodiments, carrier N for the multicarrier transmitter module 2104 corresponds to information for a base level of video resolution, while carrier 1 for the multicarrier transmitter module 2104 corresponds to information for a high level of video resolution, such as an enhanced video resolution level relative to the base level.

[00145] Program information 2148 includes information corresponding to one or more programs to be transmitted from base station 2100 (program 1 information 2162, … …, program X information 2164). Program 1 information 2162, such as video program information, includes a plurality of program 1 information portions corresponding to each carrier used by the multicarrier transmitter assembly 2104 to convey program 1 information (carrier 1 portion 1 information 2166, … …, carrier 1 portion M information 2170), … …, (carrier N portion 1 'information 2168, … …, carrier N portion M' information 2172).

[00146] Transmission scheduling information 2150, such as used by transmission scheduling module 2132 and/or generated, includes a plurality of sets of program scheduling information (program 1 scheduling information 2174, … …, program X scheduling information 2176) corresponding to one or more programs to be transmitted. Program 1 scheduling information 2174 includes a plurality of sets of program scheduling information (carrier 1 program 1 scheduling information 2178, … …, carrier N program 1 scheduling information 2180) associated with a plurality of carriers used by multicarrier transmitter assembly 2104 to transmit program 1. Carrier 1 program 1 scheduling information 2178 includes scheduling information (carrier 1/part 1 scheduling information 2182, … …, carrier 1/part M scheduling information 2184) corresponding to multiple program 1 parts. Carrier N program 1 scheduling information 2180 includes scheduling information corresponding to multiple program 1 parts (carrier N/part 1 'scheduling information 2186, … …, carrier N/part M' scheduling information 2188).

[00147] The geographic information 2152 includes multiple sets of information (carrier 1 geographic information 2190, … …, carrier N geographic information 2192) associated with different carriers used by the multi-carrier transmitter element 2104. Carrier 1 geographical information 2190 includes traffic information 2194 and carrier N geographical information 2192 includes traffic information 2196. For example, in some embodiments, a second carrier, such as carrier N, covers a wider geographical area than a first carrier, such as carrier 1, corresponding to the multicarrier transmitter module 2104, and the multicarrier transmitter module 2104 is controlled, for example via the transmission scheduling module 2132, to transmit information on traffic located within a first coverage area of the first carrier using the first carrier and to transmit information on traffic outside the first coverage area but within a coverage area of the second carrier using the second carrier.

[00148] Fig. 22 is a diagram 2200 illustrating several exemplary sets of program information (2162', 2162 ", 2162 *). The set of program information such as set 2162', set 2162 ", or set 2162 * may be any one of the sets of program information of fig. 21 (program 1 information 2162, … … program X information 2164).

[00149] The exemplary program information set 2162 ' includes a plurality of carrier 1 information sets (carrier 1 part 1 information 2166 ', … …, carrier 1 part M information 2170 ') and a plurality of carrier N information sets (carrier N part 1 ' information 2168 ', … …, carrier N part M ' information 2172 '). Carrier 1 part 1 information 2166 'includes part 1' information 2202 and additional information 2204. Carrier N part M information 2170 'includes part M' information 2206 and additional information 2208. In various embodiments, the portion 1 'information 2202 is the same as the carrier N portion 1' information 2168 'and the portion M' information 2206 is the same as the carrier N portion M 'information 2172'. In some such embodiments, additional information (2204, … …, 2208) transmitted using carrier 1 is not transmitted using carrier N with respect to multicarrier transmitter element 2104.

[00150] The exemplary program information set 2162 "includes multiple carrier 1 information sets (carrier 1 part 1 information 2166", … …, carrier 1 part M information 2170 ") and multiple carrier N information sets (carrier N part 1 'information 2168", … …, carrier N part M' information 2172 "). Carrier N part 1 'information 2168 "includes basic video program information part 1' 2210 and carrier N part M 'information 2172" includes basic video program information part M' 2222. Carrier 1 part 1 information 2166 "includes basic video program information part 1' 2210 and additional content and/or enhancement information 2212. The additional content and/or enhancement information 2212 includes at least one of video enhancement information 2213, additional video content information 2214, language support information 2216, text stream information 2218, and advertisement information 2220. Carrier 1 part M information 2170 "includes basic video program information part M' 2222 and additional content and/or enhancement information 2224. The additional content and/or enhancement information 2224 includes at least one of video enhancement information 2223, additional video content information 2226, language support information 2228, text stream information 2230, and advertisement information 2232.

[00151] The exemplary program information set 2162 * includes multiple carrier 1 information sets (carrier 1 part 1 information 2166 *, … …, carrier 1 part M information 2170 *), multiple carrier 2 information sets (carrier 2 part 1 "information 2167 *, … …, carrier 2 part M" information 2171 *), and multiple carrier N information sets (carrier N part 1 'information 2168 *, … …, carrier N part M' information 2172 *). Carrier N part 1 'information 2168 * includes a basic video program information part 1' 2238, and carrier N part M 'information 2172 * includes a basic video program information part M' 2246. Carrier 2 part 1 "information 2167 * includes mid-level part 1 'augment information 2236, and carrier N part M" information 2171 * includes mid-level part M' augment information 2242. Carrier 1 part 1 information 2166 * includes high level part 1 'augment information 2234, and carrier N part M information 2170 * includes high level part M' augment information 2240.

[00152] In some embodiments, the enhancement data associated with a particular carrier allows a level of enhancement correlation to be achieved by a wireless terminal that receives and decodes program information from both the carrier carrying the base video and the carrier carrying the enhancement information. For example, if the wireless terminal receives and successfully decodes program related carrier N and carrier 2 information, the wireless terminal may combine the information to obtain a higher mid-level video presentation than the base level video presentation. Continuing with the example, if the wireless terminal receives and successfully decodes the program related carrier N and carrier 1 information, the wireless terminal may combine the information to obtain a higher level video presentation than the medium level video presentation.

[00153] In some embodiments, the enhancement data associated with the respective carriers enables the wireless terminal to implement a base level of presentation when using the carrier associated with the base video program, and a first enhancement level when using two carriers, and a third enhancement level when using three carriers, and so on. For example, it is considered that the program information 2162 * includes information corresponding to 3 carriers such as N-3. If the wireless terminal successfully receives and decodes the carrier 3 program information, the basic video program can be displayed. If the carrier 3 program information and the carrier 2 program information are successfully received and decoded, the mid-level enhancement program may be displayed. If the carrier 3 program information, carrier 2 program information, and carrier 1 program information are successfully received and decoded, a high-level enhancement program can be displayed. In various embodiments, the power level and/or information data rate associated with a carrier is such that: the base video program is expected to have a higher probability of successful decoding than the mid-level enhancement information is expected to have, and the mid-level enhancement information is expected to have a higher probability of successful decoding than the high-level enhancement information is expected to have.

[00154] Fig. 23 is a flow diagram 2300 of an exemplary method of operating a wireless terminal. The exemplary method begins in step 2302, where the wireless terminal is powered on and initialized in step 2302. Operation proceeds from start step 2302 to step 2304.

[00155] In step 2304, the wireless terminal is operated to receive signals corresponding to a broadcast program, such as OFDM signals, including a first signal corresponding to a first carrier and a first transmitter and a second signal corresponding to a second carrier and a second transmitter, wherein at least the first carrier is different from the second carrier or at least the second transmitter is different from the first transmitter. In one example, the first and second carriers are the same and the first and second transmitters are different. In another example, the first and second carriers are different and the first and second transmitters are the same transmitter. In another example, the first and second carriers are different and the first and second transmitters are different.

[00156] In some embodiments, for example, in some embodiments using a single receiver chain, where the first and second carriers may be different, step 2304 includes sub-steps 2308, 2310, 2312, 2314, and 2316.

[00157] In sub-step 2308, the wireless terminal tunes to the first carrier, and then in sub-step 2310, the wireless terminal receives the first signal. Operation proceeds from sub-step 2310 to sub-step 2312. In sub-step 2312, the wireless terminal checks whether the first and second carriers are different. If, in sub-step 2312, the wireless terminal determines that the first and second carriers are different, then operation continues to sub-step 2314 where the wireless terminal tunes to the second carrier again. Operation proceeds from sub-step 2314 to sub-step 2316. If, in sub-step 2312, the wireless terminal determines that the first and second carriers are the same, then operation proceeds to sub-step 2316. In sub-step 2316, the wireless terminal receives a second signal.

[00158] Operation proceeds from step 2304 to step 2305. In step 2305, the wireless terminal combines the first and second signals. In some embodiments, the first signal is a base program signal and the second signal is an enhancement signal. Step 2305 includes sub-step 2318. In sub-step 2318, the wireless terminal uses the information in the second signal to enhance at least one of an audio presentation and a video presentation generated from the first signal. In various embodiments, sub-step 2318 includes at least one of sub-steps 2320 and 2324. In sub-step 2320, the wireless terminal increases the resolution of the video image included in said first signal. In sub-step 2324, the wireless terminal incorporates into the audio or video presentation additional audio or video content that was not presented in the first signal. For example, in some embodiments, the additional content includes at least one of: video content not included in the base program, audio content not included in the base program, support for additional languages not included in the base program, a text stream to be displayed with the base video content, and advertisements.

[00159] From step 2305, the process proceeds to step 2306. In step 2306, the wireless terminal generates at least one of an audio presentation and a video presentation from the combined signal.

[00160] Fig. 24 is a diagram of a flowchart 2400 of an exemplary method of operating a wireless terminal. The exemplary method begins at step 2402, where the wireless terminal is powered on and initialized at step 2402. Operation proceeds from start step 2402 to step 2404.

[00161] In step 2404, the wireless terminal is operated to receive signals corresponding to a broadcast program, the signals including a first signal corresponding to a first carrier and a first transmitter and a second signal corresponding to a second carrier and a second transmitter, wherein at least the first carrier is different from the second carrier or at least the second transmitter is different from the first transmitter. In one example, the first and second carriers are the same and the first and second transmitters are different. In another example, the first and second carriers are different and the first and second transmitters are the same transmitter. In another example, the first and second carriers are different and the first and second transmitters are different. In some embodiments, the first and second signals comprise the same content but received on different carriers or from different transmitters.

[00162] In some embodiments, for example, some embodiments in which the first and second signals are received at different times, step 2404 includes sub-steps 2416, 2418, and 2420. In sub-step 2416, the wireless terminal receives one of the first and second signals. Operation proceeds from sub-step 2416 to sub-step 2418. In sub-step 2418, the wireless terminal stores information obtained from one of the received first and second signals. Operation proceeds from sub-step 2418 to sub-step 2420. In sub-step 2420, the wireless terminal receives the other of the first and second signals that was not received in sub-step 2416.

[00163] Operation proceeds from step 2404 to step 2406. In step 2406, the wireless terminal attempts to decode at least one of the first and second signals, and then in step 2408, checks the result of the attempted decoding. If the attempt to decode of step 2406 is successful, operation proceeds from step 2408 to step 2414. If the attempt to decode at step 2406 was unsuccessful, then operation proceeds from step 2408 to step 2410. The wireless terminal combines the first and second received signals in step 2410, and then decodes the combined signal in step 2412. Operation proceeds from step 2412 to step 2414. In step 2414, the wireless terminal generates at least one of an audio presentation and a video presentation from the decoded signal information.

[00164] Fig. 25 is a diagram of an exemplary wireless terminal 2500, such as a mobile node. Exemplary wireless terminal 2500 includes a receiver module 2502, a transmitter module 2504, a processor 2506, user I/O devices 2508, and a memory 2510 coupled together via a bus 2512, wherein the various components exchange data and information via bus 2512. Memory 2510 includes routines 2524 and data/information 2526. The processor 2506, such as a CPU, executes the routines 2524 and uses the data/information 2526 in memory 2510 to control the operation of the wireless terminal and implement methods.

[00165] A receiver module 2502, such as an OFDM receiver, is coupled to a receive antenna 2503 and the wireless terminal receives downlink signals from the base station transmitter via the receive antenna 2503, the downlink signals including broadcast program information from one or more sources. Receiver module 2502 receives signals corresponding to a broadcast program, the signals including first and second signals, the first signal corresponding to a first carrier and a first transmitter, the second signal corresponding to a second carrier and a second transmitter, at least the first carrier being different from the second carrier or at least the second transmitter being different from the first transmitter. Receiver module 2502 includes a decoder 2514 for decoding at least some of the received downlink signals.

[00166] A transmitter module 2504, such as an OFDM transmitter, is coupled to transmit antenna 2505, and wireless terminal 2500 transmits uplink signals to a base station via transmit antenna 2505. In some embodiments, the uplink signal includes a registration signal and/or an access request for receiving and recovering a broadcast program. Transmitter module 2504 includes an encoder 2516 for encoding at least some of the uplink signals to be transmitted.

[00167] User I/O devices 2508 include user input devices 2518 such as keypads, keyboards, switches, microphones, camera inputs, etc., a display 2520, and an audio output device 2522 such as a speaker and associated amplification and/or audio processing circuitry.

[00168] An operator of wireless terminal 2500 uses user input device 2518 to select a broadcast program, request access, log on to the internet, and/or perform other interface operations. Display 2520 allows the user of wireless terminal 2500 to view the recovered presented video program information. The audio output device 2522 allows the user of the wireless terminal 2500 to listen to the recovered presented audio presentation information.

[00169] Routines 2524 include communications routines 2528 and wireless terminal control routines 2530. Communications routines 2528 implement various communications protocols used by wireless terminal 2500. The wireless terminal control routines 2530 include a memory module 2532, a merge module 2534, a program replay module 2536, an enhancement module 2538, a tuning module 2540, and a handoff control module 2542. The enhancement module 2538 includes a layered decoder module 2544 and a content merging module 2546.

[00170] Memory module 2532 stores a plurality of received signals corresponding to broadcast programs received from different carriers and/or different transmitters. The different transmitters may correspond to different base stations, different base station sector transmitters of the same base station, and/or different carrier transmitters for the same sector of the same base station. Broadcast program receive signal 2548 from source 1, broadcast program receive signals 2550, … … from source 2, and broadcast program receive signal 2552 from source N are examples of information stored by memory module 2532.

[00171] The combining module 2534 combines the received signals received on different carriers and/or from different base stations for generating a program presentation. The broadcast program receive signals (2548, 2550, 2552) are input to a merge module 2534 and the merged program segment corresponding to program 2554 is the output of merge module 2534.

[00172] Program replay module 2536 generates at least one of an audio presentation and a video presentation from a combined signal, such as represented by audio presentation information 2558 and video presentation information 2560.

[00173] The enhancement module 2538 uses information in a second signal, such as broadcast information received from a second source, to enhance at least one of audio presentation information and video presentation generated from a first signal, such as broadcast information received from a first source. For example, basic audio program information 2584 and/or basic video program information 2590 may be from a first signal of source 1, while audio presentation enhancement information 2586 and/or video presentation enhancement information 2590 may include information from a second signal of source 2, and enhancement module 2538 operates to cause enhanced audio presentation information 2588 and/or enhanced video presentation information 2594.

[00174] The layered decoder module 2544 increases the resolution of the video image included in the first signal, such as from the first source, by performing a layered decoding operation using the second signal, such as from the second source as an enhancement signal. In various embodiments, the layered decoder further increases the resolution of the video image by performing a layered decoding operation that includes using a third signal, such as from a third source, as the further enhancement signal.

[00175] The content merging module 2546 merges additional audio and/or video content, such as a second signal from a second source, into the audio presentation and/or the video presentation, where the additional audio and/or video content is not present in the first signal.

[00176] Tuning module 2540 tunes to one of the plurality of carriers being used by wireless terminal receiver module 2502 to receive broadcast program signals, e.g., to one of the first and second carriers corresponding to source 1 and source 2. A switch control module 2542 controls the tuning module 2540 to switch between the first and second carriers, such as according to stored timing information corresponding to broadcast program segments associated with different transmission sources.

[00177] Data/information 2526 includes one or more sets of broadcast program receive signals (broadcast program receive signal 2548 from source 1, broadcast program receive signals 2550, … … from source 2, broadcast program receive signal 2552 from source N), combined program segment 2554 corresponding to a program, source'/carrier/transmitter information 2556, audio presentation information 2558, video presentation information 2560, currently selected downlink carrier information 2562, user/device/session/resource information 2564, current base station/sector identification information 2566, system timing/frequency structure information 2568, such as an OFDM system, and directory information 2570 for a program.

[00178] Broadcast program receive signal 2548 from source 1 includes one or more segment information (segment 1 information 2572, … …, segment N information 2574). Broadcast program receive signal 2550 from source 2 includes one or more segment information (segment 1 'information 2576, … …, segment N' information 2578). Broadcast program receive signal 2552 from source N includes one or more segment information (segment 1 "information 2580, … …, segment N" information 2582).

[00179] Audio presentation information 2558 includes basic program information 2584, enhancement information 2586, and enhanced audio presentation information 2558. Video presentation information 2560 includes basic program information 2590, enhancement information 2592, and enhanced video presentation information 2594.

[00180] Source'/carrier/transmitter information 2556 includes information relating each different broadcast program signal source to the downlink carrier being used, as well as information identifying the transmitter. Currently selected downlink carrier information 2562 includes information identifying the carrier to which receiver module 2502 is currently tuned. User/device/session/resource information 2564 includes information such as user identification information, device parameter setting information, session information, and air link resource information, such as downlink traffic channel segments that the wireless terminal should receive and process in order to receive audio/video program presentations. Current base station/sector identification information 2566 includes information identifying the base station, sector, and/or carrier associated with the source of the broadcast signal being received by wireless terminal 2500. System timing/frequency structure information 2568, such as an OFDM system, includes information such as system downlink/uplink channel structure information, downlink/uplink carrier information, downlink/uplink pitch OFDM pitch block information, downlink/uplink frequency hopping information, symbol timing information, timing information related to grouping of multiple OFDM symbol transmission times, and program segment timing information. Directory information 2570 for a program includes information such as identifying a plurality of audio and/or video programs, information associating different programs with different base station attachment points, base station attachment points corresponding to base stations, base station sectors, and downlink carriers, and information identifying the type of information, such as basic programs or presentation enhancement information, being transmitted via a base station attachment point program broadcast.

[00181] Fig. 26 is a diagram of an exemplary communication system 2600, such as an OFDM communication system supporting program broadcasting. Exemplary communication system 2600 includes a plurality of base stations (base station 12602, base station 22604), a plurality of wireless terminals (wireless terminals 12606, … …, wireless terminal N2608), such as mobile nodes, and a network node 2610. Base station 12602 is a single sector base station having the cellular coverage area of cell 12603; base station 22604 is a single sector base station having a cellular coverage area of cell 22605. Base station 12602 and base station 22604 are located in close proximity to each other. The base stations (2602, 2604) are connected to a network node 2610, such as a router, via network links (2612, 2614), respectively. The network node is connected to the internet and/or other network nodes via network link 2616. The network links (2612, 2614, 2616) are, for example, optical fiber links or copper metal lines.

[00182] Wireless terminals (2606, 2608) communicate with a base station via a wireless link. The illustrated wireless terminals (2606, 2608) are receiving downlink broadcast program signals from a base station. Base station 12602 transmits downlink broadcast program signal 2618, and wireless terminals (2606 and 2608) receive it. Base station 22604 transmits downlink broadcast program signals 2620 for reception by the wireless terminals (2606, 2608).

[00183] Base station 12602 includes a transmitter module 2622, a transmission timing control module 2624, a timing synchronization module 2626, a set of program segments 2628 stored for a first program, stored transmission timing schedule information 2630, stored transmission power information 2632, and timing margin information 2627. Base station transmitter 2622 transmits the program segments corresponding to the first program, e.g., transmits at least some of the set of program segments 2628 stored for the first program. The transmission timing control module 2624 controls the first base station transmitter 2622 to transmit program segments at a different time than the time at which program segments having the same information content are transmitted by the second base station transmitter 2634. In some embodiments, the transmission timing control module 2622 controls the first base station transmitter 2622 to cause the first base station transmitter 2622 to transmit program segments having the same information content as the program segments transmitted by the second base station transmitter at non-overlapping times different from the times at which the second base station transmitter transmits the same program segments. The stored transmission scheduling information 2630 includes information indicating when the first base station transmitter 2622 transmitted a program segment corresponding to the first program using the first carrier. The stored transmission power level information 2632 includes information indicative of a first transmission power level at which program segments corresponding to a first program are transmitted from the first base station transmitter 2622 using a first carrier. In various embodiments, the first and second base station transmitter (2622, 2634) timings are not synchronized within a cyclic prefix duration. The timing synchronization module 2622 maintains timing synchronization between the first base station transmitter module 2622 and the second base station transmitter module 2634 to maintain a level of timing synchronization that is within a maximum timing margin that is greater than an OFDM cyclic prefix duration of an OFDM symbol transmitted by the first base station transmitter 2622. The timing margin information 2627 includes a maximum timing margin value used by the timing synchronization module 2626.

[00184] The base station 22604 includes a transmitter module 2634, a transmission timing control module 2636, a timing synchronization module 2638, a set of program segments 2640 stored for a first program, stored transmission timing scheduling information 2642, stored transmission power information 2644, and timing margin information 2639. The base station transmitter 2634 transmits program segments corresponding to the first program, e.g., transmits at least some of the set of program segments 2640 stored for the first program. The transmission timing control module 2636 controls the second base station transmitter 2634 to transmit program segments at a different time than the time at which program segments having the same information content are transmitted by the first base station transmitter 2622. In some embodiments, the transmission timing control module 2636 controls the second base station transmitter 2634 to cause the second base station transmitter 2634 to transmit program segments having the same information content as the program segments transmitted by the first base station transmitter 2622 at non-overlapping times different from the times at which the same program segments are transmitted by the first base station transmitter 2622. The stored transmission scheduling information 2642 includes information indicating when the second base station transmitter 2634 transmits program segments corresponding to a second program using a second carrier, which is different from the first carrier. The stored transmission power level information 2642 includes information indicating a second transmission power level at which program segments corresponding to the first program are transmitted from the second base station transmitter 2634 using a second carrier, the second transmission power level being different from the first transmission power level. The timing synchronization module 2638 maintains timing synchronization between the second base station transmitter module 2634 and the first base station transmitter module 2622 to maintain a level of timing synchronization that is within a maximum timing margin that is greater than an OFDM cyclic prefix duration of an OFDM symbol transmitted by the first base station transmitter 2622. The timing margin information 2639 includes a maximum timing margin value used by the timing synchronization module 2638.

[00185] In some other embodiments, the first and second base station transmitters are sector transmitters and at least one of the first and second transmitters is located within a multi-sector cell.

[00186] Fig. 27 is a flow chart 2700 of an exemplary method of operating a wireless terminal. The exemplary method begins in step 2702 and in step 2702 the wireless terminal is powered on and initialized. Operation proceeds from start step 2702 to step 2704. In step 2704, the wireless terminal is operated to receive a first broadcast signal corresponding to a first program on a first carrier. Operation proceeds from step 2704 to step 2706. In step 2706, the wireless terminal is operated so as to perform a first decoding operation on the first received broadcast signal, and then in step 2708, the operation is controlled based on the decoding operation result of step 2706. If the wireless terminal determines that the decoding of step 2706 was unsuccessful, operation proceeds from step 2708 to step 2710; however, if the wireless terminal determines that the decoding of step 2706 was successful, then operation proceeds from step 2708 to step 2709.

[00187] In step 2710, the wireless terminal tunes to a second carrier different from the first carrier, and in step 2712, the wireless terminal receives a second broadcast signal corresponding to the first program on the second carrier. Operation proceeds from step 2712 to step 2714. In step 2714, the wireless terminal performs a decoding operation on the second received broadcast signal, and in step 2716, controls the operation based on the result of the decoding operation in step 2714. If the wireless terminal determines that the decoding of step 2714 was unsuccessful, operation proceeds from step 2716 to step 2718; however, if the wireless terminal determines that the decoding of step 2714 was successful, operation proceeds from step 2716 to step 2720.

[00188] Returning to step 2709, in step 2709, the wireless terminal generates a renderable copy of the recovered first program information. Operation proceeds from step 2709 to step 2704 where the wireless terminal receives another broadcast signal, such as a next program segment, corresponding to the first program transmitted over the first carrier.

[00189] Returning to step 2720, the wireless terminal generates a renderable copy of the recovered first program information in step 2720. Operation proceeds from step 2720 to step 2712, where the wireless terminal receives another broadcast signal, such as a next program segment, corresponding to the first program transmitted over the second carrier.

[00190] Returning to step 2718, in step 2718, the wireless terminal tunes to the first carrier. Operation proceeds from step 2718 to step 2704 where the wireless terminal receives another broadcast signal, such as a next program segment, corresponding to the first program transmitted over the first carrier.

[00191] An alternative method that proceeds if the decoding of step 2714 is unsuccessful will now be described. If the decode of step 2714 is unsuccessful, operation proceeds from step 2716 to step 2722. In step 2722, the wireless terminal determines whether there are respective first and second available signals, e.g., whether first and second signals corresponding to the same program segment have been received, and stores the information of the first and second signals. If the information is available, operation proceeds from step 2722 to step 2724; otherwise, operation proceeds from step 2722 to step 2732. The wireless terminal combines the first and second received signals in step 2724, and then performs a decoding operation on the combined signal in step 2726. Operation proceeds from step 2726 to step 2728. In step 2728, the wireless terminal continues to operate based on the decoding operation result of step 2726. If the wireless terminal determines that the decoding was unsuccessful in step 2726, operation proceeds from step 2728 to step 2718; however, if the wireless terminal determines that the decoding was successful in step 2726, operation proceeds from step 2728 to step 2730. In step 2730, the wireless terminal generates a renderable copy of the recovered first program information. Operation proceeds from step 2730 to step 2732. In step 2732, the wireless terminal tunes to the first carrier. Operation proceeds from step 2732 to step 2704 where the wireless terminal receives another broadcast signal, such as a next program segment, corresponding to the first program transmitted on the first carrier.

[00192] Returning to step 2718, in step 2718, the wireless terminal tunes to the first carrier. Operation proceeds from step 2718 to step 2704 where the wireless terminal receives another broadcast signal, such as a next program segment, corresponding to the first program transmitted on the first carrier.

[00193] In some embodiments, after successful decoding, the recovered information is stored and a renderable copy of the already recovered first program information is generated at a later time, e.g., a renderable copy of the first program information corresponding to a set of the plurality of recovered program segments is generated.

[00194] In various embodiments, the first carrier corresponds to a first base station transmitter and the second carrier corresponds to a second base station transmitter, the first and second base station transmitters being located in a sector of a cell. In various embodiments, the first and second received signals comprise the same program content received at different times.

[00195] Fig. 28 is a diagram of an exemplary wireless terminal 2800, such as a mobile node. The exemplary wireless terminal 2800 includes a receiver module 2802, a transmitter module 2804, a processor 2806, a user I/O device 2808, a memory 2810, and a decoder module 2812 connected together via a bus 2814 where the various components exchange data and information via the bus 2814. A decoder module 2812 is also connected to the receiver module 2802 via a link 2816. In various embodiments, decoder module 2812 is included in receiver module 2802 as part of receiver module 2802 and/or in memory 2810 as part of memory 2810. Memory 2810 includes routines 2818 and data/information 2820. The wireless terminal 2800 executes the routines 2818 and controls the operation of the wireless terminal using the data/information 2820 in memory 2810.

[00196] A receiver module 2802, such as an OFDM receiver, is coupled to a receive antenna 2803 and the wireless terminal receives downlink signals including broadcast programming from one or more base station transmitters via the receive antenna 2803. In various embodiments, receiver module 2802 is a single carrier receiver capable of receiving a single carrier at a time.

[00197] A decoder module 2812 connected to the receiver module 2802 performs a decoding operation on the received broadcast signal. The decoder module 2812 may perform a decoding operation on a signal received from a single source and a decoding operation on a combined signal received from a plurality of sources.

[00198] User I/O devices 2808 allow a user to control at least some operations of wireless terminal 2800, enter information, select broadcast programs, listen to audio output presentations of received and recovered broadcast programs, and/or view video output of received and recovered broadcast programs. User I/O devices 2808 include user input devices such as keypads, keyboards, switches, touch screens, microphones, cameras, etc., display devices such as video display screens, and audio output devices such as speakers.

[00199] A transmitter module 2804, such as an OFDM transmitter, is coupled to transmit antennas 2805, and wireless terminals transmit uplink signals to base stations via the transmit antennas 2805. In some embodiments, some uplink signals include at least one of the following information: a request to access a broadcast program, such as billing information related to a broadcast program received and presented by a user of wireless terminal 2800, authentication of a charge for one or more broadcast programs. In some embodiments, the same antenna is used for receiver module 2802 and transmitter module 2804. In some embodiments, some wireless terminals 2800 do not include transmitter module 2804.

[00200] Routines 2818 include communications routines 2822 and wireless terminal control routines 2824. The communications routines perform various communications functions and implement the communications protocols used by the wireless terminal 2800. Wireless terminal control routines 2824 include a decode operation evaluation module 2826, a receiver switch control module 2828, a program segment merge module 2830, a carrier strength monitor module 2832, and a carrier selection module 2834.

[00201] The decoding operation evaluation module 2826 determines whether decoding of the broadcast signal is unsuccessful. In response to the decoding operation evaluation module 2826 determining that the decoding operation was unsuccessful, the receiver handover control module 2828 controls the receiver module 2802 to handover between carriers, such as the first and second carriers. In some embodiments, the same program segment may be recovered from signals transmitted on the first and second carriers but at different times, and the receiver switch control module 2828 includes a switching function to switch for a period of time less than the time offset between transmission of segments having the same information content.

[00202] The program segment combining module 2830 combines program segments generated by decoding signals received on different carriers to generate a renderable copy of the recovered broadcast program.

[00203] The carrier strength monitoring module 2832 checks the strength of received signals, such as received beacon and/or pilot signals, which may indicate the received strength of the first and second carrier signals. The carrier selection module 2834 performs carrier selection operations as a function of the relative reception strengths of the carriers used to transmit the broadcast program, such as the first and second carriers, as determined by the carrier strength monitoring module 2832.

[00204] Data/information 2820 includes a plurality of received program buffer sets (received program buffers 2836, … … for the first carrier, received program buffer 2838 for the nth carrier, combined program buffer 2840 corresponding to signals received from multiple carriers). In some embodiments, the first carrier corresponds to a first base station transmitter and the second carrier corresponds to a second base station transmitter, the first and second base station transmitters being located within adjacent cells or sectors. Received program buffer (first carrier) 2836 includes received program segment information (segment 1 information 2842, … …, segment M information 2844). Received program buffer (nth carrier) 2838 includes received program segment information (segment 1 information 2846, … …, segment M information 2848). Received program buffer(s) 2840 includes received program segment information (segment 1 information 2850, … …, segment M information 2852). The information in the received program buffer (first carrier) 2836 and the information in the received program buffer (nth carrier) 2838 represent information from the receiver module 2802, which may be forwarded to the decoder module 2812. The information in the merged program buffer(s) 2740 represents a merging of information received from multiple carriers, e.g., the decoder module 2712 may attempt to decode a program segment using information in the merged program buffer(s) 2740 when the received information corresponding to a first carrier alone or the received information corresponding to a second carrier cannot successfully decode the program segment.

[00205] Data/information 2820 also includes a plurality of sets of processed (such as decoded) program buffers (processed (decoded) program buffers 2854, … … for the first carrier, processed (decoded) program buffer 2856 for the nth carrier, processed (decoded) program buffers 2858 corresponding to received signals from multiple carriers). Processed (such as decoded) program buffer (first carrier) 2854 includes processed (such as decoded) program segment information (segment 1 information 2860, … …, segment M information 2862). Processed (such as decoded) program buffer (nth carrier) 2838 includes processed (such as decoded) program segment information (segment 1 information 2864, … …, segment M information 2866). Processed (such as decoded) program buffer(s) 2858 includes processed (such as decoded) program segment information (segment 1 information 2868, … …, segment M information 2870). The information in processed (decoded) program buffer (first carrier) 2854, processed (decoded) program buffer (nth carrier) 2856, and processed (decoded) program buffer (carriers) 2858 represents the output from decoder module 2812.

[00206] The merged program segment 2872 corresponding to a program represents the output of the program segment merge module 2830 and represents the merging of decoded program segment information from one or more buffers 2854, 2856, 2858. For example, sometimes information 2872 includes program segments recovered by decoding information from a single carrier, such as segment 1 information 2860, … …, segment M information 2862 corresponding to the first carrier. Sometimes information 2872 includes program segments recovered by information decoding corresponding to successful independent decoding of program segments from multiple carriers, recovering independent program segments from information from a single carrier, such as segment 1 information 2860 corresponding to a first carrier and segment M information 2866 corresponding to an nth carrier. Sometimes, information 2872 includes at least one program segment recovered from at least one separate processed carrier buffer (2854, … …, 2856) and at least one program segment recovered from processed combined program buffer 2858, e.g., segment 1 information 2858 and segment 1 information 2864. Sometimes the segment source included in information 2872 processes (decoded) the merged program buffer 2858 itself.

[00207] Carrier strength information 2876 includes measurements obtained by carrier strength monitoring module 2832, information correlating the measured signals with transmit power level information associated with the carrier used by the transmitted signal, and relative signal strength information. The carrier selection module 2834 uses the carrier strength information 2876.

[00208] The currently selected downlink carrier information 2878 includes information identifying alternate carriers to which the wireless terminal may alternately tune to in order to attempt to receive and decode the broadcast program, and information identifying the current carrier; the wireless terminal has now tuned its receiver module to the current carrier, e.g., receiver module 2802 is currently set to receive broadcast program segments on the current one of the two alternative carriers.

[00209] Current base station/sector identification information 2880 includes information identifying a base station, a sector type, and/or a downlink carrier associated with an optional base station attachment point transmitter, and information identifying an attachment point transmitter, e.g., a wireless terminal may alternately tune to an optional base station attachment point transmitter to receive a selected broadcast program; receiver module 2802 is currently tuned to the identified attachment point transmitter for reception of the broadcast program segment.

[00210] System timing/frequency structure information 2882 such as an OFDM system includes downlink/uplink channel structure information, downlink/uplink carrier information, downlink/uplink pitch hopping information, and the like. System structure information 2882 includes information identifying traffic channel segments in the downlink channel structure that are dedicated to broadcast programs.

[00211] The directory information 2884 of the program includes information identifying a plurality of different available broadcast programs. The program's schedule information 2884 includes, for a single program, information identifying the carrier used by the transmitter and the transmitter associated with the program, and the transmission timing associated with the program segment for the transmitter/carrier combination.

[00212] User/device/session/resource information 2874 includes information such as a login name, password, access information, device identification information, session information including billing information corresponding to receiving the broadcast program, and information identifying the air link resources used by the wireless terminal to recover the broadcast information.

[00213] Fig. 29 is a flow chart 2900 of an exemplary communication method. For example, an exemplary communication method may be used in an OFDM communication system, e.g., an OFDM communication system that includes broadcasting one or more programs by subdividing a program into a plurality of program segments. Operation begins in step 2902, where in step 2902, base stations in the system are powered on and initialized. Operation proceeds from start step 2902 to steps 2904 and 2906.

[00214] In step 2904, the first base station is operated to transmit information. Step 2906 includes sub-step 2908. In sub-step 2908, the first base station is operated to transmit a plurality of different program segments corresponding to the first program.

[00215] In step 2906, a second base station located adjacent to the first base station is operated to transmit information transmitted by the first base station, and information transmitted by the second base station is transmitted such that the first and second base stations transmit the same information at different times. Step 2906 includes sub-step 2912. In sub-step 2912, the second base station is operated to transmit the same plurality of different program segments corresponding to the first program, but to transmit segments having the same information content from a time offset from the segments having the same information content transmitted by the first base station.

[00216] In some embodiments, at least during certain times, step 2904 includes sub-step 2910, and step 2906 includes sub-step 2914. In step 2910, the first base station is operated to transmit a plurality of different program segments corresponding to the second program. In step 2914, the second base station is operated to transmit the same plurality of different program segments corresponding to the second program, but with segments having the same information content being transmitted from a time offset from the segments having the same information content transmitted by the first base station.

[00217] In various embodiments, operating the first base station to transmit information comprises transmitting information using a first carrier, and operating the second base station to transmit information comprises transmitting information using a second carrier, the second carrier having a different frequency than the first carrier. In some such embodiments, the first and second base stations transmit the information at different power levels.

[00218] In some embodiments, transmitting information from the first base station includes transmitting information using at least one OFDM symbol and a cyclic prefix having a cyclic prefix duration, and the first and second base stations are not synchronized within the cyclic prefix duration.

[00219] Fig. 30 is a diagram of an exemplary communication system 3000, such as an OFDM communication system supporting program broadcasting. Exemplary communication system 3000 includes a plurality of base stations (base station 13002, base station 23004), a plurality of wireless terminals (wireless terminals 13006, … …, wireless terminal N3008), such as mobile nodes, and a network node 3010. Base station 13002 is a single sector base station that has the cellular coverage area of cell 13003; base station 23004 is a single-sector base station having the cellular coverage area of cell 23005. Base station 13002 and base station 23004 are located in close proximity to each other. The base stations (3002, 3004) are connected to a network node 3010, such as a router, via network links (3012, 3014), respectively. The network node is connected to the internet and/or other network nodes via network link 3016. The network links (3012, 3014, 3016) are, for example, optical fiber links or copper metal lines.

[00220] The wireless terminals (3006, 3008) communicate with the base station via a wireless link. The wireless terminals (3006, 3008) are shown receiving downlink broadcast program signals from a base station. Base station 13002 transmits downlink broadcast program signal 3018, which wireless terminals (3006, 3008) receive. Base station 23004 transmits downlink broadcast program signal 3020, which is received by wireless terminals (3006, 3008).

[00221]The base station 13002 includes a transmitter module 3022, a transmission timing control module 3024, a power control module 3026, a set of stored program segments 3028 for a first program, stored transmission timing schedule information 3030, stored transmission power information 3032, and timing margin information 3027. Such as using the carrier frequency f₁The base station transmitter 3022 of the OFDM transmitter of (a) transmits information, e.g., information within a set of stored program segments 3028 for a first program, such as a video program. The transmission time control module 3024 controls the first base station transmitter 3022 to transmit the same information transmitted by the second base station transmitter, but with a time difference from the transmission of the second transmitter, so that the first base station transmitter and the second base station transmitter transmit portions of the same information, e.g., program segments, having the same content at different times. The power control module 3026 controls the first base station transmitter 3022 to operate at, for example, a power level P₁To transmit information at a first power level.

[00222]The stored transmission scheduling information 3030 includes information indicating when the first base station transmitter 3 is022 using a catalyst such as f₁Transmits information corresponding to the program segment of the first program. The stored transmission power level information 3032 includes information indicating a first transmission power level, such as P₁Using the first carrier from the first base station transmitter 3022, a program segment corresponding to the first program is transmitted. In various embodiments, the first and second base station transmitter (3022, 3034) timing are synchronized to a level that is greater than the cyclic prefix duration but less than the difference in transmission timing between transmissions by the first base station transmitter and the second base station transmitter of portions of information, such as program segments, having the same information content. The timing margin information 3027 includes a maximum timing margin value that the transmission timing control module 3026 is using, such as with respect to the level of synchronization between the first and second base station transmitters (3022, 3040).

[00223]Base station 23004 includes a transmitter module 3034, a transmission timing control module 3036, a set of stored program segments 3040 for a first program, stored transmission timing schedule information 3042, stored transmission power information 3044, and timing margin information 3039. Such as using the carrier frequency f₂Base station transmitter 3034 of the OFDM transmitter of (1) transmits information, e.g., within a set of stored program segments 3040 for a first program, such as a video program, where f₂And f₁Different. The information within the set of stored program segments 3040 for the first program has the same content as the information within the set of stored program segments 3028 for the first program. The transmission time control module 3036 controls the second base station transmitter 3034 to transmit the same information transmitted by the first base station transmitter but with a time difference from the transmission of the first transmitter so that the first base station transmitter and the second base station transmitter transmit the same information portion, e.g., a program segment, having the same content at different times. In some such embodiments, segments from different sources, such as base station 1 transmitter 3022 and base station 2 transmitter 3034, that convey the same information are timed so as not to overlap. Power control module 3038 pairing second base station transmitters3034 controlling to operate at a power level such as P₂Is transmitted at a second power level, wherein P₂And P₁Different.

[00224]The stored transmission scheduling information 3042 includes instructions indicating when the second base station transmitter 3034 is to use information such as f₂The second carrier of (a) transmits information corresponding to the program segment of the first program. Stored transmission power level information 3044 includes information indicating a second transmission power level, such as P₂Using the second carrier from the second base station transmitter 3044 to transmit the program segment corresponding to the first program at the second transmission power level. In various embodiments, the first and second base station transmitter (3022, 3034) timing are synchronized to a level that is greater than the cyclic prefix duration but less than the difference in transmission timing between transmissions by the first base station transmitter and the second base station transmitter of portions of information, such as program segments, having the same information content. The timing margin information 3039 includes a maximum timing margin value that the transmission timing control module 3036 is using, such as with respect to the level of synchronization between the first and second base station transmitters (3022, 3040).

[00225] It is noted that various embodiments maintain a relatively coarse level of synchronization between neighboring base stations. In some embodiments, coarse level transmitter timing synchronization is controlled in the system by a node other than the base station, such as network node 3010. In some embodiments, the base stations 3002, 3004 exchange signaling to coordinate and maintain synchronization of the coarse level. In some embodiments, the base stations need not exchange signaling for the purpose of achieving and/or maintaining this coarse level synchronization between the base stations, and in various embodiments, the base stations do not exchange signaling for the purpose of achieving and/or maintaining this coarse level synchronization between the base stations. In some such embodiments, a separate base station, such as base station 3002, uses its own timing reference, such as a precision clock reference signal, and/or an external timing source reference signal, in order to maintain a desired coarse level of timing synchronization between the base stations.

[00226] In some other embodiments, the first and second base station transmitters are sector transmitters and at least one of the first and second transmitters is located within a multi-sector cell.

[00227] Fig. 31 is a diagram of an exemplary base station 3100 such as an access node. Exemplary base station 3100 includes a multicarrier receiver assembly 3102, a multicarrier transmitter assembly 3104, a processor 3106, an I/O interface 3108, and a memory 3110 coupled together via a bus 3112, where various components exchange data and information over bus 3112. Memory 3110 includes routines 3126 and data/information 3128. The base station 3100 executes the routines 3126 and uses the data/information 3128 in memory 3110 to control the operation of the base station 3100 and implement methods.

[00228] A multicarrier receiver component 3102, such as an OFDM receiver component, is connected to receive antennas 3103 and base station 3100 receives uplink signals from wireless terminals via receive antennas 3103. In some embodiments, the received uplink signal includes a request to access the broadcast program, information indicating user authentication for charging the broadcast program, and/or billing information related to the broadcast program accessed by the wireless terminal. Receiver component 3102 includes a decoder for decoding at least some of the received signals. In some embodiments, for example, in some embodiments where the base station 3100 is only functional in a broadcast mode with respect to its wireless interface, the receiver component 3102 is not included.

[00229] A multicarrier transmitter element 3104, such as an OFDM multicarrier transmitter element, is connected to transmit antennas 3105 and the base station 3100 transmits downlink signals to the wireless terminals via the transmit antennas 3105, at least some of the transmitted signals comprising broadcast program signals. Two alternative exemplary embodiments of multicarrier transmitter module 3104 are illustrated. In the first embodiment, one three-carrier transmitter module 3116 is included, while in the second embodiment, three separate single-carrier transmitter modules (carrier 1 transmitter module 3118, carrier 2 transmitter module 3120, carrier 3 transmitter module 3122) are used. For example, in some embodiments, if a three-carrier transmitter module 3116 is used, the three-carrier transmitter module 3116 may generate an OFDM symbol comprising three non-overlapping downlink pitch blocks, e.g., one OFDM symbol using 339 pitches and comprising three pitch blocks each having 113 pitches, each pitch block being associated with a carrier frequency used by the wireless terminal to recover the individual gene blocks. As another example, in some embodiments, if three separate carrier transmitter modules (3118, 3120, 3122) are used, each OFDM symbol corresponding to a carrier is independently generated and transmitted, e.g., using a tone block with 113 tones per OFDM symbol. Multicarrier transmitter assembly 3104 also includes encoder module 3124 to encode at least some downlink signals.

[00230] I/O interface 3108 is used to connect base station 3100 to the internet and/or other network nodes such as program content servers, other base stations, routers, security server nodes, billing nodes, and the like.

[00231] Routines 3126 include a communications routine 3128 and base station control routines 3130. The communications routines 3128 implement the various communications protocols used by the base station 3100 and perform various communications operations such as controlling the I/O interface 3108. The base station control routines 3130 include a carrier 1 transmission control module 3132, a carrier 2 transmission control module 3134, a carrier 3 transmission control module 3136, a program transmission control module 3138 and a content control module 3146. The program transmission control module 3138 includes a carrier 1 program resolution level 1 sub-module 3140, a carrier 2 program resolution level 2 sub-module 3142, and a carrier 3 program resolution level 3 sub-module 3144.

[00232]Carrier 1 transmission control module 3132 controls multicarrier transmitter module 3104 with respect to carrier 1 transmission, e.g., carrier f₁The transmission of upper program information is controlled at a power level P₁Data rate R₁The above. Carrier 2 transmission control module 3134 controls multicarrier transmitter module 3104 with respect to carrier 2 transmission, e.g., carrier f₂The transmission of upper program information is controlled at a power level P₂Data rate R₂The above. Carrier 3 transmission control moduleBlock 3136 controls the multicarrier transmitter module 3104 with respect to carrier 3 transmission, e.g., carrier f₃The transmission of upper program information is controlled at a power level P₃Data rate R₃The above.

[00233] The program transmission control module 3138 operation includes controlling a video resolution level corresponding to the transmitted signal. The carrier 1 program resolution level 1 sub-module 3140 controls the video program transmitted at least in part at the first video resolution level on carrier 1. The carrier 2 program resolution level 2 sub-module 3142 controls the video program transmitted at least in part on carrier 2 at a second video resolution level, e.g., a lower resolution level than the resolution level used with respect to carrier 1. A carrier 3 program resolution level 3 sub-module 3144 controls the video program transmitted at least in part at the third video resolution level on carrier 3.

[00234] The content control module 3146 controls the content in the broadcast segments corresponding to the different carriers. In some embodiments, the content control module 3146 performs operations to include at least some program information that is the same on multiple carriers, such as first and second carriers or first, second, and third carriers, but with different resolutions. The content control module 3146 incorporates the video program information 3174 into the broadcast transmission segment associated with each carrier.

[00235]Data/information 3128 includes carrier 1 power level information 3148, which includes a transmission power level P₁Information for performing the identification; carrier 2 power level information 3150, which includes a power level P for transmission₂Information for performing the identification; and carrier 3 power level information 3152 including a transmission power level P₃Information of the identification is performed. In various embodiments, P₁Is not equal to P₂And P is₂Is not equal to P₃。

[00236]Data/information 3128 also includes carrier 1 frequency information 3154, which includes identifying downlink carrier 1 as f₁Is sent toInformation; carrier 2 frequency information 3156, which includes identifying downlink carrier 2 as f₂The information of (a); and carrier 3 frequency information 3158, including identification of downlink carrier 3 as f₃The information of (1). In various embodiments, f₁And f₂Is different from and f₂And f₃Different. In some such embodiments, a non-overlapping downlink pitch block, such as an OFDM pitch block with 113 pitches, is associated with each of the three carriers.

[00237]Data/information 3128 also includes carrier 1 data rate information 3160, which includes R₁Information identifying the information data rate to be used for broadcast program segments on carrier 1; carrier 2 data rate information 3168, which includes R₂Information identifying the information data rate to be used for broadcast program segments on carrier 2; and carrier 3 data rate information 3170, which includes R₃Information identifying the information data rate to be used for broadcast program segments on carrier 3. In various embodiments, R₁And R₂Is different and R₂And R₃Different.

[00238] The data/information 3128 also includes broadcast program information 3172 and broadcast program transmission information 3180. The broadcast program information 3172 includes video program information 3174. The video program information 3174 includes a plurality of pieces of information (information 13176, information M3178) corresponding to the video program. In various embodiments, the broadcast program information 3172 includes information corresponding to a plurality of different programs. In some embodiments, broadcast program information 3176 includes audio program information.

[00239] The broadcast program transmission information 3180 includes a plurality of information sets corresponding to carrier 1 (carrier 1 segment 1 information 3182, … …, carrier 1 segment N information 3184), a plurality of information sets corresponding to carrier 2 (carrier 2 segment 1 information 3186, … …, carrier 2 segment N information 3188), a plurality of information sets corresponding to carrier 3 (carrier 3 segment 1 information 3190, … …, carrier 3 segment N information 3192), and transmission scheduling timing information 3194.

[00240] The techniques of the various embodiments may be implemented using software, hardware or a combination of software and hardware. Various embodiments are directed to an apparatus, e.g., a mobile node such as a mobile terminal, a base station, a communication system. Also directed is a method, e.g., a method of controlling and/or operating a mobile node, such as a host, a base station and/or a communication system. Various embodiments are also directed to a machine-readable medium, such as a ROM, RAM, CD, hard disk, etc., which includes machine-readable instructions for controlling a machine to perform one or more steps.

[00241] In various embodiments nodes described herein are implemented using one or more modules to perform steps corresponding to one or more methods, e.g., signal processing, message generation and/or transmission steps. Thus, in some embodiments, various features are implemented using modules. These modules may be implemented using software, hardware, or a combination of software and hardware. Many of the above described methods or method steps can be implemented using machine executable instructions, such as software, embodied in a machine readable medium such as a memory device, e.g., RAM, floppy disk, etc. to control a machine, e.g., general purpose computer with or without additional hardware, to implement all or portions of the above described methods, e.g., in one or more nodes. Accordingly, in other instances, various embodiments are directed to machine-readable media including machine executable instructions for causing a machine, such as a processor and associated hardware, to perform one or more of the steps of the above-described methods.

[00242] Although described in the context of an OFDM system, at least some of the methods and apparatus of the various embodiments may be used in a wider range of communication systems, including many non-OFDM and/or non-cellular systems.

[00243] Many additional variations on the methods and apparatus of the various embodiments described above will be apparent to those skilled in the art in view of the above description. Such variations are considered to be within the scope of the invention. The methods and apparatus may be used with, and in various embodiments are used with, CDMA, Orthogonal Frequency Division Multiplexing (OFDM), and/or various other types of communications techniques which may be used to provide wireless communications links between access nodes and mobile nodes. In some embodiments the access nodes are implemented as base stations which establish communications links with mobile nodes using OFDM and/or CDMA. In various embodiments the mobile nodes are implemented as notebook computers, Personal Digital Assistants (PDAs), or portable devices including receiver/transmitter circuits and logic and/or routines, for implementing the described methods.

Claims (69)

1. A method of communication, comprising:

operating a first base station transmitter to transmit a program segment corresponding to a first program; and

operating a second base station transmitter located adjacent to said first base station transmitter to transmit the same program segments of said first program as said first base station, but said first and second base stations transmitting segments having the same information content at different times.

2. The communication method of claim 1, wherein the first and second base station transmitters are transmitters located in adjacent single sector cells.

3. The communication method of claim 1, wherein the first and second base station transmitters are sector transmitters located within neighboring sectors, and wherein the communication method is used in a system having a multi-sector cell, the neighboring sectors being sectors in the same cell or sectors in neighboring multi-sector cells.

4. The communication method of claim 1, wherein operating the first base station transmitter to transmit a program segment corresponding to the first program comprises: transmitting the program segment corresponding to the first program using a first carrier; and is

Wherein operating the second base station transmitter to transmit program segments corresponding to the same program segment comprises: transmitting the program segment corresponding to the first program using a second carrier, the second carrier having a different frequency than the first carrier.

5. The communication method of claim 1, wherein operating the first base station transmitter to transmit a program segment corresponding to the first program comprises: transmitting the program segment using a first carrier and a first transmission power level; and is

Wherein operating the second base station transmitter to transmit a program segment corresponding to the first program comprises: transmitting the first program segment using a second carrier having a different frequency than the first carrier and a second transmission power level different from the first transmission power level.

6. The communications method of claim 5, wherein the first and second base station transmitters correspond to different cells, the method further being unsynchronized with cyclic prefix durations.

7. The communication method of claim 1, wherein operating the second base station transmitter located adjacent to the first base station transmitter to transmit the same program segment of the first program comprises: operating the second base station transmitter to transmit program segments having the same information content as the program segments transmitted by the first base station transmitter at a time that is offset from the time the program segments having the same information content are transmitted by the first base station transmitter.

8. The communications method of claim 7, wherein said information program segments are transmitted using OFDM symbols transmitted with a cyclic prefix, and wherein the transmission time offset between program segments having the same information content transmitted by said first and second base station transmitters is greater than the duration of the cyclic prefix.

9. The communication method of claim 8, wherein the first and second base station transmitters are not synchronized within a cyclic prefix duration, and wherein the transmission timing offset between program segments having the same information content transmitted by the first and second base stations exceeds the duration of a symbol transmission time period, the symbol transmission time period comprising a time for transmitting one OFDM symbol and a corresponding cyclic prefix.

10. The communications method of claim 9, wherein the time offset between transmission of a program segment by the first base station and transmission of a program segment having the same program content by the second base station is at least equal to an amount of time used to transmit the program segment.

11. The communications method of claim 9, wherein the time offset between transmission of a program segment by the first base station and transmission of a program segment having the same program content by the second base station is at least equal to an amount of time used by the first base station to transmit the program segment.

12. The communication method of claim 11, wherein when the second base station transmits a program segment corresponding to the first program, the first base station does not transmit a program segment corresponding to the first program, and the first and second base stations transmit program segments corresponding to the first program in an interleaved manner.

13. The communications method of claim 12, wherein the first and second base stations periodically transmit the interleaved program segments, a transmission time between program segments corresponding to the first program being less than 5 seconds.

14. The communication method of claim 1, wherein the first and second base stations each transmit using multiple carrier frequencies, and wherein neighboring base stations use different transmission power levels for the same carrier frequency.

15. The communications method of claim 14, wherein each carrier frequency corresponds to a different OFDM tone base block, tones in each different OFDM tone base block being non-overlapping in frequency.

16. A communication system, comprising:

at least one set of stored program segments corresponding to a first program;

a first base station transmitter that transmits a program segment corresponding to the first program;

a second base station transmitter, located adjacent to said first base station transmitter, for transmitting at least some program segments of said first program transmitted by said first base station; and

a transmission time control module that controls at least the second base station transmitter to transmit program segments at a time different from a time at which the first base station transmitter transmits program segments having the same information content.

17. The system of claim 16, wherein the first and second base station transmitters are transmitters within a single sector cell.

18. The system of claim 16, wherein the first and second base station transmitters are sector transmitters, and wherein at least one of the first and second transmitters is located within a multi-sector cell.

19. The system of claim 16, further comprising:

stored transmission scheduling information indicating when the first base station transmitter transmits a program segment corresponding to the first program using a first carrier; and indicating when the second base station transmitter transmits a program segment corresponding to the first program using a second carrier, wherein the second carrier has a carrier frequency different from a carrier frequency of the first carrier.

20. The system of claim 16, the stored transmission power level information corresponding to the first base station transmitter indicating a first transmission power level at which program segments corresponding to the first program are transmitted from the first base station transmitter using a first carrier; and is

The additional stored transmission power level information corresponding to the second base station transmitter indicates a second transmission power level at which program segments corresponding to the first program are transmitted from the second base station transmitter, wherein the second transmission power level is different from the first transmission power level.

21. The system of claim 20, wherein the first and second base station timings are not synchronized to within a cyclic prefix duration.

22. The system of claim 16, further comprising:

a timing synchronization module for maintaining timing synchronization between the first and second base station transmitters to maintain a level of timing synchronization within a maximum timing margin that is greater than an OFDM cyclic prefix duration of an OFDM symbol transmitted by the first base station transmitter.

23. The system of claim 16 wherein said transmission time control module controls at least said second base station transmitter to transmit program segments having the same information content as program segments transmitted by said first base station transmitter at non-overlapping times different from times at which the same program segments are transmitted by said first base station transmitter.

24. A communication system, comprising:

first base station transmitter means for transmitting a program segment corresponding to a first program; and

second base station transmitter means located adjacent to said first base station transmitter for transmitting the same program segments of said first program as said first base station, but said first and second base station transmitter means transmit segments having the same information content at different times.

25. The communication system of claim 24, wherein said first and second base station transmitter means are transmitters located in adjacent single sector cells.

26. The communication system of claim 24, wherein said first and second base station transmitter means are sector transmitters located in adjacent sectors of a multi-sector cell.

27. A method of operating a wireless terminal, comprising:

receiving a first broadcast signal corresponding to a first program on a first carrier;

performing a first decoding operation on the received first broadcast signal;

determining whether the first decoding operation is unsuccessful; and

tuning to a second carrier different from the first carrier if it is determined that the decoding operation was unsuccessful.

28. The method of claim 27, further comprising:

operating the wireless terminal to receive a second broadcast signal corresponding to the first program on the second carrier.

29. The method of claim 28, further comprising:

performing a second decoding operation on the received second broadcast signal.

30. The method of claim 29, further comprising:

determining whether the second decoding operation is unsuccessful; and

tuning to the first carrier if it is determined that the decoding operation was unsuccessful.

31. The method of claim 30, further comprising:

switching between the first and second carriers in a continuous manner when the received signal cannot be decoded.

32. The method of claim 27, wherein the first carrier corresponds to a first base station transmitter and the second carrier corresponds to a second base station transmitter, the first and second base station transmitters being located within adjacent cells or sectors.

33. The method of claim 27, wherein the received first and second signals comprise the same program content, but the received first and second signals are received at different times.

34. The method of claim 33, further comprising:

combining signals received on the first and second carriers to generate a renderable copy of the first program.

35. A wireless terminal, comprising:

a receiver for receiving broadcast signals transmitted at different times on first and second carriers;

a decoder, connected to the receiver, for performing a decoding operation on the received broadcast signal;

a decoding operation evaluation module for determining whether decoding of the broadcast signal is unsuccessful; and

a control module that controls the receiver to switch between the first and second carriers in response to the decoding operation evaluation module determining that a decoding operation was unsuccessful.

36. The wireless terminal of claim 35, further comprising:

a program segment combining module that combines program segments generated by decoding signals received on different carriers to generate a renderable copy of the broadcast program.

37. The wireless terminal of claim 35, wherein the same program segment can be recovered from signals transmitted on the first and second carriers but at different times, the control module including a switching function that switches over a period of time that is less than the time offset between transmission of segments having the same information content.

38. The wireless terminal of claim 36, further comprising:

a carrier strength monitoring module that checks the strength of a signal, the strength indicating the received strength of the first and second carrier signals; and

a carrier selection module that performs a carrier selection operation based on the relative received strengths of the first and second carriers determined by the carrier strength monitoring module.

39. The wireless terminal of claim 36, wherein the receiver is a single carrier receiver capable of receiving a single carrier at a time.

40. The wireless terminal of claim 35, wherein said first carrier corresponds to a first base station transmitter and said second carrier corresponds to a second base station transmitter, said first and second base station transmitters being located in adjacent cells or sectors.

41. A wireless terminal, comprising:

receiver means for receiving broadcast signals transmitted on first and second carriers at different times;

decoder means, coupled to said receiver, for performing a decoding operation on said received broadcast signal;

decoding operation evaluation means for determining whether decoding of the broadcast signal is unsuccessful; and

control means for controlling the receiver to switch between the first and second carriers in response to the decoding operation evaluation module determining that a decoding operation was unsuccessful.

42. The wireless terminal of claim 41, further comprising:

program segment combining means for combining program segments generated by decoding signals received on different carriers to generate a renderable copy of the broadcast program.

43. A wireless terminal according to claim 41, wherein the same program segment can be recovered from signals transmitted on the first and second carriers but at different times, the control means comprising means for switching between the first and second carriers for a period of time less than the time offset between transmission of segments having the same information content.

44. The wireless terminal of claim 42, further comprising:

carrier strength monitoring means for checking the strength of signals indicative of the received strength of the first and second carrier signals; and

carrier selection means for performing a carrier selection operation in dependence upon the relative received strengths of the first and second carriers as determined by the carrier strength monitoring module.

45. A method of communication, comprising:

operating a first base station to transmit information; and

operating a second base station located adjacent to the first base station to transmit the information transmitted by the first base station, the information transmitted by the second base station being transmitted such that the first and second base stations transmit the same information at different times.

46. The communications method of claim 45, wherein operating the first base station to transmit information comprises: transmitting the information using a first carrier; and is

Wherein operating the second base station to transmit information comprises: transmitting the information using a second carrier, the second carrier having a different frequency than the first carrier.

47. The communications method of claim 46, wherein the first and second base stations transmit the information at different power levels.

48. The method of claim 46, wherein transmitting the information from the first base station comprises: transmitting the first information using at least one OFDM symbol and a cyclic prefix having a cyclic prefix duration without synchronizing the first and second base stations within the cyclic prefix duration.

49. The communications method of claim 45, wherein the information corresponds to program segments of a program transmitted by the first and second base stations, the method further comprising:

operating the first base station to transmit a plurality of different program segments corresponding to the program; and

operating the second base station to transmit the same plurality of different program segments but with a time offset from the transmission by the first base station of segments having the same information content.

50. A communication system, comprising:

a first base station comprising a first transmitter for transmitting information;

a second base station located adjacent to the first base station, including a second transmitter for transmitting the same information transmitted by the first base station; and

a transmission time control module for controlling at least the second base station transmitter to transmit the same information transmitted by the first base station transmitter with a time difference from the transmission of the first transmitter such that the first and second transmitters transmit the same information portions with the same content at different times.

51. The system of claim 50, wherein the first transmitter is a first carrier transmitter that transmits on a first carrier, and

wherein the second transmitter is a second carrier transmitter that transmits on a second carrier, the first and second carriers having different carrier frequencies.

52. The system of claim 51, further comprising:

a power control module to control the second transmitter to transmit the information at a power level different from a power level at which the first transmitter transmits the information.

53. The system of claim 51, wherein the first and second transmitters are OFDM transmitters that are timing synchronized to a level that is greater than a cyclic prefix duration but less than a difference in transmission time between transmissions by the first and second transmitters of the information portions having the same information content.

54. The system of claim 50, wherein the information corresponds to a video program, and wherein the portion of information is a program segment.

55. A computer-readable medium embodying instructions for performing a method of operating a first base station transmitter and a second base station transmitter, the method comprising:

operating the first base station transmitter to transmit a program segment corresponding to a first program; and

operating said second base station transmitter located adjacent to said first base station transmitter to transmit the same program segments of said first program as said first base station, but said first and second base stations transmitting segments having the same information content at different times.

56. The computer readable medium of claim 55, wherein the first and second base station transmitters are transmitters located in neighboring single sector cells.

57. The computer readable medium of claim 55, wherein the first and second base station transmitters are sector transmitters located in neighboring sectors, and wherein the communication method is used in a system having a multi-sector cell, the neighboring sectors being sectors in the same cell or sectors in neighboring multi-sector cells.

58. The computer-readable medium of claim 55, further comprising instructions for:

transmitting a program segment corresponding to the first program using a first carrier as part of the step of operating the first base station transmitter to transmit the program segment corresponding to the first program; and

transmitting the program segment corresponding to the first program using a second carrier as part of the step of operating the second base station transmitter to transmit program segments corresponding to the same program segment, wherein the second carrier has a different frequency than the first carrier.

59. The computer-readable medium of claim 55, further comprising instructions for:

using a first carrier and a first transmission power level for transmitting a program segment corresponding to the first program as part of the step of operating the first base station transmitter to transmit the program segment; and

transmitting the first program segment using a second carrier and a second transmission power level as part of the step of operating the second base station transmitter to transmit program segments corresponding to the first program, wherein the second carrier has a different frequency than the first carrier and the second transmission power level is different than the first power level.

60. A computer-readable medium embodying instructions for performing a method of operating a wireless terminal, the method comprising:

receiving a first broadcast signal corresponding to a first program on a first carrier;

performing a first decoding operation on the received first broadcast signal;

determining whether the first decoding operation is unsuccessful; and

tuning to a second carrier different from the first carrier if it is determined that the decoding operation was unsuccessful.

61. The computer readable medium of claim 60, further comprising instructions for:

the wireless terminal is operated to receive a second broadcast signal corresponding to the first program on a second carrier.

62. The computer readable medium of claim 61, further containing instructions for:

performing a decoding operation on the received second broadcast signal.

63. The computer readable medium of claim 62, further comprising instructions for:

determining whether the second decoding operation is unsuccessful; and

tuning to the first carrier if it is determined that the decoding operation was unsuccessful.

64. The computer readable medium of claim 63, further comprising instructions for:

switching between the first and second carriers in a continuous manner when the received signal cannot be decoded.

65. A computer-readable medium embodying instructions for performing a method of operating a first base station transmitter and a second base station transmitter, the method comprising:

operating the first base station to transmit information; and

operating the second base station located adjacent to the first base station to transmit the information transmitted by the first base station, the information transmitted by the second base station being transmitted such that the first and second base stations transmit the same information at different times.

66. The computer readable medium of claim 65, further comprising instructions for:

transmitting information using a first carrier as part of the step of operating the first base station to transmit the information; and

as part of the step of operating the second base station to transmit information, transmitting the information using a second carrier, the second carrier having a different frequency than the first carrier.

67. The computer readable medium of claim 66, further comprising instructions for:

the first and second base stations are controlled to transmit the information at different power levels.

68. The computer readable medium of claim 66, further comprising instructions for:

transmitting the first information using at least one OFDM symbol and a cyclic prefix having a cyclic prefix duration without synchronizing the first and second base stations within the cyclic prefix duration as part of the step of transmitting the information from the first base station.

69. The computer readable medium of claim 65, wherein said information corresponds to program segments of a program transmitted by said first and second base stations, said computer readable medium further comprising instructions for:

operating the first base station to transmit a plurality of different program segments corresponding to the program; and

operating the second base station to transmit the same plurality of different program segments but with a time offset to the transmission of segments having the same information content by the first base station.