MXPA06004520A - Transmission of overhead information for reception of multiple data streams - Google Patents

Abstract

Techniques for transmitting overhead information to facilitate efficient reception of individual data streams are described. A base station may transmit multiple data streams on multiple data channels (or MLCs). The MLCs may be transmitted at different times and on different frequency subbands. The time-frequency location of each MLC may change over time. The overhead information indicates the time-frequency location of each MLC and may be sent as"composite"and"embedded"overhead information. The composite overhead information indicates the time-frequency locations of all MLCs and is sent periodically in each super-frame. A wireless device receives the composite overhead information, determines the time-frequency location of each MLC of interest, and receives each MLC at the indicated time-frequency location. The embedded overhead information for each MLC indicates the time-frequency location of that MLC in the next super-frame and is transmitted along with the payload of the MLC in the current super-frame.

Description

as to the applicant 's entitlement to claim the priority of the Published: earlier application (Rule 4.17 (iii)) for all designations - without international search report and to be republished as to the applicant's entitlement to claim the priority of the upon receipt of that repon earlier application (Rule 4.17 (iii)) for all designations For two-letter codes and other abbreviations, refer to the "Guides to the applicant's entitlement to claim the priority of the ance Notes on Codes and Abbreviations" appearing at the beginning-earlier application (Rule 4.17 (iii)) for all designations no ofeach regular issue of the PCT Gazette.

TRANSMISSION OF OVERLOAD INFORMATION FOR THE RECEPTION OF MULTIPLE DATA CURRENTS FIELD OF THE INVENTION The present invention relates generally to communication and more specifically to techniques for transmitting overload information for the reception of multiple streams of data in a communication system.

BACKGROUND OF THE INVENTION A base station in a wireless communication system can simultaneously transmit multiple data streams for broadcast, multicast and / or single broadcast services. A broadcast transmission is sent to all wireless devices within a designated coverage area, a multicast transmission is sent to a group of wireless devices, and a single broadcast transmission is sent to a specific wireless device. For example, the base station may broadcast a number of data streams for multimedia programs, (eg, television) via a terrestrial radio link for reception by wireless devices. In general, the base station can transmit any number of data streams, which may change over time, and each data stream may have a fixed or variable data rate. A wireless device within the coverage area of the base station may be interested in receiving only one or a few specific data streams among the multiple data streams transmitted by the base station. If the base station multiplexes all data streams into a composite stream prior to its transmission, then the wireless device may need to receive the signal transmitted by the base station, process the received signal (eg, downstream, demodulate and decode) to obtain the composite current sent by the base station, and perform the demultiplexing to extract one or some specific data streams of interest. That type of processing may not be problematic to receive intended units to be turned on all the time. However, many wireless devices are portable and powered by internal batteries. The demodulation continues and the decoding of the received signal to recover only one or a few data streams of interest can consume significant amounts of battery power, which can greatly shorten the "ON" time for the wireless device.

If the multiple data streams are transmitted separately, then the base station can also transmit control information in a dedicated control channel to indicate when and where each data stream will be transmitted. In this case, the wireless device may need to continuously decode the dedicated control channel to obtain control information for each data stream of interest, which may deplete the battery power. The wireless device may also need to simultaneously decode each data stream of interest along with the dedicated control channel, which may increase the complexity of the wireless device. Therefore, there is a need in the art for techniques for sending overload information so that the individual data streams of interest for the wireless devices can be efficiently received at reduced power consumption.

SUMMARY OF THE INVENTION Techniques for transmitting overload information to facilitate efficient reception of individual data streams are described herein. A base station can transmit multiple data streams in multiple data channels. A channel The data is also called a multiplexed logical channel (MLC) in the following description although it may also be referred to by some other terminology. Each MLC can carry one or more data streams and can be transmitted at different times, in different frequency subbands, and so on. The time-frequency location of each MLC may change over time. The overload information indicates the time-frequency location where each MLC is transmitted. The overload information for all MLCs can be sent in two parts called "composite" overload information and "embedded" overload information. In one embodiment, the composite overload information includes the location information for all the MLCs and is sent periodically at the start of each superframe for a predetermined duration of time, as described in the following. The composite overhead information for each superframe contains location information for each MLC for that superframe, and that location information indicates the frequency-time location where the MLC will be transmitted in the superframe. A wireless device can receive the composite overload information for a current superframe, determine the frequency-time location of each MLC of interest based on location information for the MLC, and receive each MLC of interest in the current superframe at the indicated frequency-time location. Periodic and known transmission of the composite overload information allows the wireless devices in the system to quickly acquire each MLC of interest, decode each desired MLC with minimum "on" time and quickly switch between MLCs. The composite overload information can be split into a large area portion and a local area portion. The wide area portion may contain location information for all MLCs with an extensive coverage area (eg, nationwide). The local area portion may contain location information for all MLCs with a local coverage area (for example, citywide). The wide area and local area portions can be processed differently by the base station and the wireless devices for solid reception performance. In one embodiment, the embedded overload information for each MLC in each superframe contains location information for that MLC for a future superframe (eg, next), and is transmitted together with the payload of the MLC in the current superframe. A wireless device that receives a given MLC can obtain the embedded overload information for that MLC as part of the processing for the MLC the current superframe. The wireless device can then use this information to receive the MLC in the next superframe, without having to "wake up" and receive the composite overload information sent in the next superframe. Various aspects and embodiments of the invention are described in further detail in the following.

BRIEF DESCRIPTION OF THE DRAWINGS The features and nature of the present invention will become more apparent from the detailed description set forth in the following when taken in conjunction with the drawings in which like reference characters are correspondingly identified completely and where : FIGURE 1 shows a wireless multi-carrier diffusion system; FIGURE 2 shows a superframe structure. copy; FIGURE 3 shows the exemplary packet processing for an MLC; FIGURE 4 shows allocation of intervals to an MLC using a "zigzag" model; FIGURE 5 shows an exemplary message for carry location information for multiple MLCs; FIGURE 6 shows the transmission of composite and embedded overload information; FIGURE 7 shows a process for transmitting overload information; FIGURE 8 shows a block diagram of a base station; FIGURE 9 shows a block diagram of a wireless device; DETAILED DESCRIPTION OF THE INVENTION The word "exemplary" is used herein to mean that "it serves as an example, case or illustration." Any modality or design described in this "exemplary" does not necessarily have to be interpreted as preferred or advantageous over other modalities or designs. The techniques described herein for transmitting overload information can be used for wired and wireless communication systems, for time division multiplexed (TDM), frequency division multiplexed (FDM), and code division multiplexing (CDM) systems. , for single-input single-output (SISO) and multiple-input-multiple-output (MIMO) systems, for single-carrier systems and multicarriers, etcetera. Multiple carriers can be provided by orthogonal frequency division multiplexing (OFDM), some other multi-carrier modulation techniques or some other construction. OFDM effectively divides the general system bandwidth into multiple (N) orthogonal subbands. These sub-bands are also referred to as tones, bearers, subcarriers, deposits and frequency channels. With OFDM, each subband is associated with a respective support that can be modulated with data. The techniques described herein can also be used for broadcast, multicast and single broadcast services. For clarity, these techniques are described in the following for an exemplary wireless multi-carrier broadcast system. FIGURE 1 shows a wireless multi-carrier broadcast system 100. System 100 includes a number of base stations 110 that are distributed through the system. A base station is usually a fixed station and can also be called an access point, a transmitter or some other terminology. The wireless devices 120 are located throughout the entire coverage area of the system. A wireless device can be fixed or mobile and can also be called user terminal, mobile station, user equipment or some other terminology. A The wireless device can also be a portable unit such as a cell phone, a pocket device, a wireless module, a personal digital assistant (PDA), and so on. Each base station can transmit large area content, local area content, or a combination of both. Large area content is content sent over a large coverage area (for example, throughout the country), and local area content is content sent over a smaller coverage area (for example, citywide). Neighboring base stations can transmit the same or different contents. Each base station can also transmit multiple streams of data for wide area and / or local area content to wireless devices within its coverage area. These data streams can carry multimedia content such as video, audio, teletexts, data, video / audio fragments, and so on. Data streams are sent in data channels or MLC. In a specific embodiment that is described in detail in the following, each MLC can carry up to three data streams, for example, a data stream for signaling and up to two data streams for packet / traffic data. Each multimedia program can be sent as one or more streams of data, for example, different streams of data for different multimedia contents such as video, audio, data, and so on. One or more streams of data for each multimedia program may be sent in one or more MLC. For example, an MLC can carry two streams of data for a given program - one stream of data for real-time content and another stream of data for a piece of video that is played along with the content in real time at designated times. As another example, Two MLC can carry three streams of data for a single multimedia program (eg television) - one MLC can carry one stream of data for video and another stream of data for data, and a second MLC can carry one stream of data for audio. Transmitting the video and audio portions of the program in separate MLCs allows wireless devices to independently receive the video and audio. In general, each MLC can carry any number of data streams, and each multimedia program can be sent in any number of data streams and in any MLC number. FIGURE 2 shows an exemplary superframe structure that can be used for system 100. Data transmission occurs in superframe units 210.

Each superframe encompasses a predetermined duration of time, which can be selected based on several factors such as, for example, the desired statistical multiplexing for the data streams, the amount of time diversity desired for the data streams, the acquisition time for the data streams, the buffer requirements for the wireless devices, and so on. . A superframe size of about one second can provide a good exchange between the various factors observed in the above. However, other superframe sizes can also be used. A superframe can also be called a frame, a time slot, or some other terminology. For the embodiment shown in FIGURE 2, each superframe includes a field 212 for a TDM pilot, a field 214 for the overload information, and four frames 600 from 216a to 216d of equal size. The TDM pilot can be used by the wireless devices for synchronization (eg, frame detection, frequency error estimation, time acquisition, etc.) and possibly for channel estimation. The overload information indicates the specific location of each data channel within the superframe and can be sent as described below. The data streams are multiplexed and sent in the four frames. FIGURE 2 shows a superframe structure specific. In general, a superframe can cover any length of time, include any number and any type of fields, and have any number of frames. The system can also use other frame structures for transmission. In one embodiment, the protocol stack for the system includes top layers that reside on top of a current layer, which resides on top of a media access control layer (MAC), which also resides in the top of a physical layer. The upper layers control the transmission of multimedia content, access to content, and so on. The current layer provides the link of the packets of the upper layers to the data streams on an MLC basis by MLC. The MAC layer performs packet multiplexing for different data streams associated with each MLC. The physical layer provides a mechanism for transmitting multiple streams of data via a communication channel. FIGURE 3 shows a modality of the packet formats used for the current layer, the MAC layer, and the physical layer. FIGURE 3 also shows processing for an MLC in a superframe. The MLC can carry up to three data streams, which are designated as current 0, 1 and 2. Current 0 can be used to send signaling for MLC, and streams 1 and 2 can be used to send different multimedia content (eg, video, audio, data broadcast, multicast, etc.). The signaling can be for several elements such as, for example, a decryption key used to decipher the other data streams that are sent in the MLC. (The decryption key can be deciphered by a wireless device that has an appropriate subscription key, which can be obtained with the activation of a service). Other types of signaling can also be sent in stream 0. For example, stream 0 can carry a presentation record that defines the characteristics of the media carried by the MLC, the location of the MLC itself in the next superframe, text components and / or means, etcetera. In general, each stream can carry more than one type of media, although it may be more convenient to carry only one type of media in each stream. For each superframe, the current layer provides a packet of current layers for each data stream sent in the MLC in that superframe. For clarity, the following description assumes that three streams of data are being sent in the MLC. The MAC layer forms a MAC capsule for MLC for each superframe in which the MLC is transmitted. The MAC capsule includes a MAC capsule header and a MAC capsule payload. The MAC capsule header carries embedded overload information for the MLC, which can be used to receive the MLC in a future superframe (for example, the next one). The payload of the MAC capsule carries the packets of the current layer that are sent in the current superframe for the data streams carried by the MLC. The MAC layer forms N0 MAC layer packets (or simply, MAC packets) for the MAC capsule header and the 0 current packet, Ni MAC packets for the current packet 1, and N2 MAC packets for the MAC packet. the current pack 2, where Ns + > 1, N? + _ 1 and N2 + > 1, if the three data streams are being sent. To facilitate the independent reception of the data streams, each packet of current layers is sent in a whole number of MAC packets, and the length of each pack of current layers is included in the overload information. The MAC layer also performs block coding in the MAC packets (N0 + N + N2) for the MLC and generates Np parity MAC packets, where Np > 0 and is independent of whether the block coding is enabled or not, and if it is enabled, the block coding mode is selected for MLC. For each superframe in which MLC is transmitted, the MAC layer provides a coded MAC capsule which contains data (No + N? + N2 + NP) and parity MAC packets. The physical layer receives the MAC capsule encoded and processes (eg, encodes, interleaves and maps by symbols) each MAC packet to generate a corresponding physical layer (PL) packet. In one embodiment, the MAC packets are of a fixed size (eg, approximately 1K bytes), the PL packets for the MLC are of equal size, and the PL packet size is determined by the code rate and the modulation scheme used by the MLC. The one-to-one mapping between MAC packets and PL packets simplifies processing at the base station and wireless devices. The data may be transmitted in various ways in the system 100. In one embodiment, the M intervals are formed in each symbol period and mapped into the M set of non-overlapping or non-overlapping subbands, where M > 1. To obtain frequency diversity, the subbands in each set can be distributed evenly across the N total subdanders in the system. The subbands in each set are then interleaved with the subbands in each of the other M-l sets. Each set of sub-bands can be called "interlaced" in this way. Each interval can be mapped in different interleaved different periods of symbols (eg, based on a predetermined mapping scheme) to improve frequency diversity and obtain other benefits. For clarity, the following description is for the transmission of data in intervals, and interleaving interval mapping is not described. For a given superframe structure, a fixed number of intervals is available for transmission in each superframe. Some of the available ranges can be used to transmit an FDM pilot, which can be used by wireless devices for channel estimation and other purposes. Some intervals can also be assigned to a control channel used to transmit signaling for MLC, as described in the following. The remaining intervals are then available for assignment to the MLCs. Each MLC can be "assigned" a variable fixed number of intervals in each superframe depending on the MLC payload, the availability of intervals in the superframe, and the possibility of other factors. Each "inactive" MLC, which is an MLC that is not transmitted in a given superframe, is assigned zero intervals. Each "active" MLC, which is an MLC that is transmitted in a given superframe, is assigned at least one interval. Each active MLC also "assigns" intervals specific within the superframe based on an allocation scheme that attempts to (1) package the intervals for all active MLCs as efficiently as possible, (2) reduce transmission time for each MLC, (3) provide adequate time diversity for each MLC, and (4) minimize the amount of signaling necessary to indicate the intervals assigned to each MLC. Several schemes can be used to assign ranges for MLCs. In general, there is an exchange between time diversity and energy savings. The system can provide flexibility to allow energy consumption to be favored with the diversity of time, or vice versa, for different MLCs. For example, some MLCs can be optimized with time diversity while other MLCs can be optimized for power consumption. MLCs containing many turbo coding blocks inherently achieve more diversity and time, while lower data rate MLCs can benefit from additional time diversity. FIGURE 4 shows an exemplary slot mapping scheme that allocates slots to the MLCs using a "sinusoidal" or "zigzag" model. For this scheme, a frame is divided into one or more "bands", and each band covers at least one interval index and also encompasses a contiguous number of (for example, all) periods of symbols in the plot. Each active MLC is mapped in a band and intervals are assigned in that band. The intervals in each band can be assigned to the MLCs mapped for that band in a specific order using a vertical zigzag model. This zigzag model selects intervals from the lowest interval index for the band to the highest interval index for the band, one symbol period at a time, starting with the first symbol period for the band. FIGURE 4 also shows the allocation of intervals to a given MLC x for a frame 216. MLC x is assigned intervals starting from a start interval index (Start Interval) in a designated symbol period index (Interval Offset) ) and it goes to a higher interval index (Maximum Interval), then it starts from a lower interval index (Minimum Interval) in the next symbol period index and goes to the highest interval index, and so on, until that the number of intervals assigned to MLC x is reached. For the example shown in FIGURE 4, MLC x is assigned 16 intervals beginning at the interval index 4 in the symbol period index 3, which zigzags between the lowest interval index 2 and the highest interval index 5 , and that concludes in the interval index 3 in the symbol period index 7.

An exemplary slot allocation scheme has been described in the foregoing. MLCs can also be assigned ranges in other ways using other schemes. For example, each MLC can be assigned intervals in a rectangular model in the two-dimensional plane (2-D) for the interval versus symbol period as shown in figure four. Active MLCs can also be assigned rectangular models so that these models are packaged as efficiently as possible in the frame. The ranges assigned to each active MLC for each superframe can be transported in the location information sent to the MLC. The parameters used to describe the ranges assigned to each active MLC are typically dependent on the scheme used to assign the intervals. For example, if each active MLC is assigned a rectangular model, then this model can be described by two corners, for example, the interval index and the symbol period index for the lower left corner of the model and the interval index and the index of symbol period for the upper right corner of the model. If each active MLC is assigned intervals using the zigzag model, then the intervals assigned for the MLC can be described by the Start Interval, the Minimum Interval, the Interval Maximum, and the number of intervals assigned to the MLC as shown in FIGURE 4. FIGURE 5 shows a modality of a System Parameter Message used to carry location information for the MLCs. In general, the location information for each MLC includes all the parameters used to describe the time-frequency location for the MLC, for example, the specific intervals assigned to the MLC. For the modality shown in FIGURE 5, the System Parameter Message contains a message header and one or more location records. The message header may carry information such as (1) the system time for the start of the current superframe, (2) a network identifier (3), the message source, (4) a supported protocol version by the system, (5) transmission parameters for a control channel (described in the following), (6) the MLC, for the first location record sent in the message just after the header, (7) the location registration number (Nrec) that is sent in the message, etcetera. In general, the message header can contain any information relevant to wireless devices. The message carries the Nre location records for the MLCs, Nrec after the message header, a location record for each MLC, where Nrec__l - In one mode, each location record has a fixed length or L-bit size, and the Nrec location records are sent in sequential order based on the identifiers (IDs) for the MLCs . For example, if the first location record is for MLC x, then the second location record is for MLC x + 1, the third record is for MLC x + 2, and so on, and the last location record is for MLC x + NEEc -1- This allows wireless devices to quickly find and extract the location record for each MLC of interest. For the mode shown in FIGURE 5, each location record contains 1 bit, present MLC that is sent to? 1 'if the associated MLC is sent in the current superframe and 0 is set otherwise. If the Present MLC bit is sent ^ 1 ', then the location record carries an Interval Offset field, an Interval Information field, and a Current Length field. The Interval Offset field indicates the first start symbol period index for the intervals assigned to the MLC. The Interval Information field contains the interval information that carries all the parameters used to describe the assigned intervals (for example, Minimum Interval, Start Interval and Maximum Interval). Field of Current Lengths carried the length of each pack of current layers carried by the MLC in the current superframe (eg, N_N? and N2 for the three current layer packets in FIGURE 3). The number of intervals assigned to the MLC can be determined based on the current lengths and transmission parameters (e.g., code rate and modulation scheme) used for the MLC. If the present MLC bit is set to '0', then the location record carries a field of Next Superframe Offset and Reserved field. The Next Superframe Offset field indicates the next superframe in which the MLC can be sent. If this field is set 0 ', then the MLC can be sent in any outgoing superframe. If this field is set to a non-zero value, then this value indicates the minimum number of superframes for the following superframes where the MLC can continue. For example, if the Next Superframe Offset field is set to four, then the MLC will not be sent to at least five superframes of the current superframe. Wireless devices can begin to search for the next occurrence of the MLC that starts in this future superframe. Table 1 summarizes the various fields of the location record for an MLC.

Table 1 MLC Present = xl '(MLC Active) Displacement Indicates the symbol period index of Start Interval for the intervals assigned to the MLC Information Contains parameters describing the Interval intervals assigned to the MLC Lengths Contains the length of each Current layer package of current carried by the MLC in the current superframe. MLC Present = * 0 '(MLC Inactive) Displacement Indicates the next superframe in which the MLC can be sent from Superframe. Next Reserved Fill to make the location registration to a fixed size.

The interval information can be encoded to reduce the number of bits needed to carry this information. An exemplary coding scheme for the interval information is described in the following. This coding scheme for the allocation of intervals using the zigzag model shown in FIGURE 4 and further assumes that the lowest interval index for any MLC is one and the highest interval index is 7. The interval index 0 can used for the FDM pilot, the control channel, and so on. With the above assumption, the lowest interval index (Minimum Interval), the start interval index (Start Interval), and the highest interval index (Maximum Interval) for any MLC are related as follows: 1 < Minimum Interval < Start slot < Maximum Interval < 7. Ec (1) The delta or difference between the Start and Lower Interval indices and the delta between the highest start interval indices can be calculated as follows:? Initial = Minimum Interval Slot, and Ec (2)? Maximum = Interval Maximum-Start Interval. Ec (3) The interval information for each MLC can be given by a value of interval information code (Interval Information Code) which is determined based on Minimum Interval,? Nalial, and? Maximum for each MLC. Table 2 shows an exemplary mapping of the Minimum Interval and the Maximum Interval for the Interval Information Code.

Table 2 If the maximum interval rate is 7, then the parameters Minimum Interval, Start Interval and Maximum Interval can each be carried with three bits, and the interval information for each MLC can be carried with 9 bits for all three parameters. The Interval Information Code can be carried with 7 bits for the 84 possible code values shown in Table 2. The coding scheme described in the above in this way reduces the number of bits needed to carry the interval information for each MLC. The packet lengths of current layers can also be coded to reduce the number of bits needed to carry this information. An exemplary coding scheme for packet lengths of current layers is described as follows. This coding scheme is for the packet formats shown in FIGURE 3 and further assumes (1) up to three packets of current layers can be sent at any MLC in a superframe and (2) the three packets of current layers have small sizes , medium and large. For the modality shown in FIGURE 5, the Current Lengths field contains a Current Mode subfield, a Length Format subfield, a Small Current Length subfield, a Middle Current Length subfield, and a subfield of Long Current Length. The Current Mode subfield is set to 'O7 to indicate that two packets of current layers are sent on the MLC and l' is set to indicate that three packets of current layers are sent on the MLC. The Length Format subfield indicates the sizes of the current layer packets, for up to three streams of data sent in the MLC. Table 3 shows an exemplary definition of the Length Format subfield for different packet sizes of current layers for the three data streams.

Table 3 For the mode shown in Table 3, a data stream carried by the MLC is designated as a "large" stream, a data stream is designated as a "medium" stream, and a third stream of data (if it is sent) it is designated as a "small" current. The packets of current layers for the large, medium and small currents can carry up to Ngran_e, Nm_dia, and Npequeña, MAC packets respectively. The Large Current Length Subfield indicates the length of the current layer packet for the large current sent in the MLC and contains large bits, where Bgrandes = log2 (Ngran_es). The Medium Current Length subfield indicates the length of the current layer packet for the average current sent in the MLC and contains B-bits / where (N-Means) • The subfield of Small Current Length indicates the packet length of current layers for the small current (if any) sent in the MLC and contains bits Bpequenos, on e Bpeq_eñ0 = l? G2 (Npegueño) • FIGURE 5 shows the case in which three data streams are sent in the MLC, and three subfields are used to indicate the lengths of the current layer packages for these three streams of data. If only two data streams are sent in the MLC, then the B small bits for the small stream can be used for the medium or large stream (not shown in FIGURE 5). If each data stream is sent in the MLC it can carry up to 1024 MAC packets in each superframe, then a length of a 10-bit current length subfield can be used for each data stream. In this case, 30 bits can be used to carry the packet lengths of current layers for the three data streams carried in the MLC. However, if the three data streams have different lengths and if the currents large, medium and small they can carry up to 1024, 256, and 2 MAC packets, respectively, then B large = 10, B medium = 8, and B small = l bits can be used for the three streams. If one bit is used for the Current Mode subfield and three bits are used for the Length Format subfield, then a total of 23 bits can be used to carry the packet lengths of current layers for the three data streams led by the MLC. The coding scheme described in the above can thus reduce the number of bits needed to carry the current lengths for each MLC. A specific coding scheme for the interval information and a specific coding scheme for the current lengths have been described in the above. Other coding schemes can also be used, for example, for different slot allocation schemes, different packet formats, and so on. Different coding schemes can achieve different number of bit savings. In any case, the bit savings achieved with coding can be important for a large number of MLCs. Since the overload information is sent periodically and since the overload bits are relatively expensive, it is desirable to minimize the number of overload bits as much as possible for greater efficiency. FIGURE 6 shows a mode for transmitting composite and embedded overload information in a form that facilitates efficient reception of data streams. The composite overload information is sent at the start of each superframe in a TDM form and contains location information for all the MLCs. For example, a System Parameter Message may contain location information for all MLCs that carry large area content and another System Parameter Message may contain location information for all MLCs that carry local area content. The System Parameter Message for each type of coverage (large area or local area) contains a location record for each MLC, that carries content of that type of coverage. Each location record in each System Parameter Message contains location information (eg, start offset, interval information, and current lengths) for the associated MLC for the current superframe, if the MLC is active. A coded MAC capsule is transmitted in the current superframe for each active MLC. In one embodiment, the MAC capsule encoded is divided into 4 portions of equal size, in each portion it is further processed and transmitted in a frame in the intervals assigned to the MLC. The transmission of the MAC capsule encoded on four frames provides time diversity and solid reception performance in an attenuation channel that varies with time slowly. "For each MLC, the same slot allocation can be used for the four superframe frames, as shown in FIGURE 6, and this slot assignment is carried in the location record for that MLC. of capsule MAC for the MAC capsule for each MLC x contains location information for MLC x for the next superframe, if the MLC will be transmitted 'in that superframe. For the mode based on FIGURE 6, the MAC capsule header contains an MLC ID field and an SF field of the Next Content. The MLC ID field carries MLC ID x. The SF field of the Next Content is set to? L 'if MLC x will be transmitted in the next superframe and' 0 'is set otherwise. If MLC x is transmitted in the next superframe, then the MAC capsule header also contains an Interval Offset field in the Next SF, an Interval Information field in the Next SF, and a Current Length field in the Next SF, which carry the same type of information as the fields of Interval Displacement, Interval Information and Current Lengths, respectively the location record. However, the fields of Interval Displacement, Interval Information and Current Lengths in the Location Register carry "current" overload information for the MLC x for the current superframe. The Interval Offset fields of the Next SF, Interval Information of the Next SF, and Current Lengths of the Next SF in the MAC capsule header carry "future" overload information for the MLC x for the next superframe. In one modality, if MLC x does not transmit the next superframe, then the MAC capsule header also contains a Next Superframe Offset field and a Reserved field (not shown in FIGURE 6), which carry the same type of Information such as the Next Superframe Offset field and the Reserved field respectively in the location record. In another embodiment, if MLC x is not transmitted in the next superframe, then the MAC capsule header carries the location information (eg, Interval Offset field of the Next SF, Interval Information field of the Next SF, and Field of Current Lengths of the Next SF) for MLC x for the next superframe in which MLC x will be transmitted. As shown in FIGURE 6 a wireless device that has recently been switched on has been changed to a new MLC that can receive the composite overload information sent at the start of each superframe and determine the location where the new MLC will be sent in the current superframe . The wireless device can then receive the MAC capsule for this new MLC at the location indicated by the location register for MLC. A wireless device can obtain from the MAC capsule header, the embedded overload information for this MLC for the next superframe. The wireless device can then use this embedded overload information to receive the MLC in the next superframe, without having to process the composite overload information sent at the start of the next superframe. If the MLC is continuously transmitted in each superframe, which is often the case for a multimedia program, then the wireless device may need to receive the composite overload information only once. The wireless device may thereafter obtain the embedded overload information for MLC for each future superframe of the MAC capsule header. In this way, the wireless device can be turned ON during a shorter time duration and may be able to save more battery power. The MLC ID is used to ensure that the wireless device is processing the MAC capsule for the appropriate MLC, for example, in the event that MLC is decoded in error. FIGURE 7 shows a process 700 for transmitting the overload information for multiple data channels or MLC. The location information for each MLC for the current superframe is determined (for example, block 712). The location information for each MLC indicates the time-frequency location for MLC and may have the format shown in FIGURE 5 or some other format. The location information for each MLC is for a future superframe (for example, next) is also determined (for example, block 714). The composite overload information for the current superframe is formed with the location information for all the MLCs for the current superframe (block 716) and is transmitted at the start of the current superframe in a TDM form (block 718). The location information for each MLC for the future superframe is transmitted together with the payload for MLC in the current superframe (block 720). For the modalities described in the above, the overload information is sent in two parts. The composite charge information is sent periodically to start of each superframe (which may be relatively rare, for example, once every second), and carries the interval assignments for all the MLCs sent in that superframe. A wireless device can use the composite overload information if it is requesting content for the first time (for example, after powering up), if an MLC of interest was decoded in error in a previous superframe, if the wireless device is receiving a new MLC , if the wireless device changes the reception of a current MLC to a new MLC, and so on. A wireless device can use the embedded overload information to determine when to wake up in the next superframe. If the wireless device has successfully decoded an MLC of interest in the current superframe, then the wireless device does not need to wake up to receive the composite overload information sent in the next superframe. This reduces the ON time for the wireless device to receive data streams. The overload information embedded in this way is an energy efficient way to provide the location where the MLC will be sent to the next superframe. The wireless device can obtain this embedded overload information as part of the processing for MLC. If each MLC carries embedded overload information only for itself and no other MLC, as described above, then the embedded overload information only needs to point to a single location in the next super-frame for this MLC. Embedded overload information is protected by the same error correction coding used for the MLC payload, which ensures solid reception of the embedded overload information. The superframe duration can be selected so that the composite and embedded overload information consumes a relatively small percentage of the total capacity of the system while still allowing for rapid changes between data channels. The division of overburden information into large area and local area portions provides several benefits. The overload data bits for the wide area portion can be sent in a form to obtain the benefits of using OFDM in a single frequency network (SFN). For example, a wireless device can receive and combine the overload data bits of multiple base stations to obtain higher reception reliability. The overload data bits for the local area portion can be transmitted differently to those for the wide area portion, for example, using a different OFDM pilot structure, a lower code rate, a lower order modulation scheme, etc., in order to improve the reception of these bits within the limits of the local coverage areas. In general, the portions of large area and local area can be processed with the same or different coding and modulation schemes, they can have the same or different formats and lengths, and so on. The overload information is processed and transmitted to make it as solid as the traffic data. The location information for each MLC can be sent once to allow wireless devices to receive the MLC. The location information for each MLC can be sent in the overhead information composed at the start of each superframe. The location information for each active MLC can also be sent redundantly together with the payload so that the MLC improves efficiency upon receiving the MLC. However, this redundant location information is optional and may be omitted (ie, not transmitted). Overload information for data channels can also be sent in other ways. For example, current lengths can be included in the MAC capsule header instead of the location record. If MLCs are programmed more than one superframe in anticipation, then the location record and / or the MAC capsule header may also include location information for a superframe that is also outside the next superframe. The MAC capsule header may include a bit to indicate whether the location information for the next superframe is the same as for the current superframe, in which case the location information may be omitted from the MAC capsule header. The overload information indicates the location where each MLC is transmitted. A control channel can be used to carry other information relevant to the MLCs. For example, the control channel can carry, for each MLC, the code rate and the modulation scheme used for the MLC, the block coding used for MLC, the type of medium that is sent in each data stream carried by the MLC. the MLC, the upper layer entity that is linked to each data stream carried by the MLC, and so on. The control channel can be sent in a manner that is known a priori by the wireless devices, which are then able to receive control without other signaling. FIGURE 8 shows a block diagram of a base 11Ox station, which is one of the base stations in the system 100. The base 11Ox station, a 810 processor Transmission data (TX) receives multiple streams of data (T) (denoted as { di.}. to { dt.}.) from data sources 808, where T > 1. Each data stream can carry a packet of current layers for each superframe in which the data stream will be sent (for example, as shown in FIGURE 3). The TX data processor 810 also receives the embedded overload data attached to each MLC and appends the overload data in a suitable current layer packet that is sent in the MLC (eg, as shown in FIGURE 3) . The TX data processor 810 processes each data stream according to a "mode" used for that stream to generate a corresponding data symbol stream. The mode for each data stream may indicate, for example, the code rate, the modulation scheme, etc. to use the data stream. The TX data processor 810 provides T data symbol streams (denoted as {sx.}. To { St.}.) To a symbol multiplexer (Mux) / changer 820. As used herein, a data symbol is a modulation symbol for packet / traffic data, an overload symbol is a modulation symbol for overload data, a pilot symbol is a modulation symbol for pilot (the which is data that is known a priori by the base station and the devices wireless) a protection symbol is a signal value of zero, and a modulation symbol is a complex value for a point in a constellation of signals used for a modulation scheme (eg, M-PSK, M-QAM, etc.) The TX data processor 810 also receives the composite overload data to be sent at the beginning of each superframe (which is denoted as { D0.}.) Of an 840 controller. The TX data processor 810 processes the data. compound overload data according to a mode used for the overload data and provides a current of overload symbols (denoted as { s0.}.) for channeler 820. The composite overload data can be split into a wide area portion and a local area portion (as shown in FIGURE 6) and processed separately for example, based on the same or different modes. The mode (s) used for compound overload data is scientifically made with a lower code rate and a lower order modulation scheme for those used for data streams to ensure solid reception of composite overload data in time-selective and / or frequency-selective terrestrial radio channels. The channelizer 820 multiplexes the symbols of data T streams of data symbols in their assigned ranges. The channelizer 820 also provides pilot symbols at the intervals used for the pilot transmission and the protection symbols in sub-bands not used for transmission. The channelizer 820 further multiplexes the pilot symbols and the overload symbols in the pilot and overload fields at the start of each superframe, as shown in FIGURE 2. The channelizer 820 provides a composite stream of symbols (denoted. {Sc}) which carries data, overload, pilot and protection symbols in the appropriate sub-bands and symbol periods. An OFDM modulator 830 performs the modulation of OFDM in the composite symbol stream and provides a stream of OFDM symbols to a transmission unit 832 (TMTR). The transmission unit 832 conditions (e.g., analogizes, filters, amplifies, and up-converts by frequency) the OFDM symbol stream and generates a modulated signal that is transmitted from an antenna 834. The controller 840 directs the operation in the base llOx station. A memory unit 842 provides storage for programming code and data used by the controller 840. The controller 840 and / or a scheduler 844 allocate and provide intervals to the MLCs.

FIGURE 9 shows a block diagram of a wireless 12Ox device, which is one of the wireless devices in the system 100. An antenna 912 receives the modulated signal transmitted by the base station 110x and provides the received signal to a receiver 914 (RCVR). Receiving unit 914 conditions, digitizes and processes the received signal and provides a sample stream to a demodulator 916 OFDM. The OFDM demodulator 916 performs the OFDM demodulation in the sample stream to obtain the received pilot symbols and the received data and the overload symbols. A controller 940 derives a channel response estimate for the radio link between the base station 11Ox and the wireless device 120x based on the received pilot symbols. The demodulator 916 OFDM also performs the coherent detection (eg, equalization or correlated filtering) in the received data and the overload symbols with the channel response estimate and provides the data to a demultiplexer (Demux) / 920 symbol decanalizer. detected "and the overload symbols, which are estimates of the transmitted data and the overload symbols, respectively. The controller 940 obtains the indication (e.g., user selection for) one or more MLC for received by the wireless device. The controller 940 then determines the slot assignment for each selected MLC based on either (1) the composite overload information sent at the start of the current superframe or (2) the embedded overload information sent in the capsule header of the received MAC in a previous superframe for the MLC. The controller 940 then provides a control signal for the decanalizer 920. The decanalizer 920 performs the demultiplexing of the detected data and the overload symbols for each symbol period based on the control signal and provides one or more streams of data symbols detected and / or a stream of detected overload symbols to the RX data processor 930. The RX data processor 930 processes (eg, symbolizes, deinterleaves, and decodes) the detected overload symbol stream in accordance with the mode used for the composite overload data and provides the decoded overload data to the controller 940. The RX data processor 930 also processes each stream of detected data symbols for each MLC of interest, according to the mode used for that stream, and provides a decoded data stream corresponding to a data collector 932. In general, the processing of the 12Ox device of Wireless is complementary to the processing in the base station. The 940 controller also directs the operation on the wireless 12Ox device. A memory unit 942 provides for the programming codes and data used by the controller 940. The techniques described herein for transmitting overload information may be implemented by various means. For example, these techniques can be implemented in hardware, software, or a combination thereof. For a hardware implementation, the processing units in a base station can be implemented within one or more specific application integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs) , programmable logic devices (PLD), field programmable gate arrangements (FPGA), processors, controllers, microcontrollers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. The processing units in a wireless device can also be implemented within one or more ASICs, DSPD, and so on. For a software implementation, the techniques described herein can be implemented with modules (for example, procedures, functions, etc.) that perform the functions described herein. The software codes may be stored in a memory unit (e.g., memory unit 842 and / or 942) and executed by a processor (e.g., controller 840 and / or 940). The memory unit can be implemented inside the processor or external to the processor. The prior description of the described embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but to be in accordance with the broader scope consistent with the principles and novel features described herein.

Claims (46)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and therefore the property described in the following claims is claimed as property.
2. CLAIMS 1. A method for transmitting overload information in a communication system, characterized in that it comprises: determining the location information for each of a plurality of data channels, the location information for each data channel indicates the location of the data. times, frequency location, or both of the time and frequency location where the data channel is transmitted; generate overload information with the location information for the plurality of data channels; and transmitting the overload information in a time division multiplexed (TDM) form with data for the plurality of data channels. The method according to claim 1, further characterized in that it comprises: transmitting at least one data stream in each of the plurality of data channels.
3. 3. The method according to claim 2, characterized in that the location information for each data channel indicates the same number of data streams transmitted in the data channel. The method according to claim 2, characterized in that the location information for each data channel indicates the size for each data stream that is transmitted in the data channel. The method according to claim 1, further characterized in that it comprises: transmitting the plurality of data channels in superframes, each superframe having a predetermined time duration, and wherein the transmission of the overload information in a TDM form comprises transmit overload information in each superframe in a TDM form with the data for the plurality of the data channels. The method according to claim 5, characterized in that the overload information transmitted in each super-frame comprises the location information for the plurality of data channels for the super-frame. 7. The method of compliance with the claim 5, characterized in that the determination of the location information for each of the plurality of data channels comprises generating location information for each data channel for a current superframe indicating whether or not the data channel is transmitted in the current superframe . The method according to claim 5, characterized in that the determination of the location information for each of the plurality of data channels comprises for each data channel transmitted in a current super-frame, generating information location for the channel of data may indicate a start time in which the data channel is transmitted in the current superframe. The method according to claim 5, characterized in that the determination of the location information for each of the plurality of data channels comprises for each data channel not transmitted in a current superframe, generating location information for the channel of data to indicate a next faster super-frame in which the data channel is potentially transmitted. 10. The method according to claim 1, further characterized in that it comprises: transmitting the plurality of data channels in a plurality of intervals, each interval being associated with a respective set of frequency sub-bands. The method according to claim 10, characterized in that the plurality of intervals is assigned a plurality of interval indices, and where the determination of the location information for each of the plurality of data channels comprises generating location information for each channel to indicate a lower interval index, a Home Interval index, and a higher interval index used for the data channel. 12. The method according to claim 11, characterized in that the determination of the location information for each of the plurality of data channels further comprises mapping the lowest interval index, the start interval index and the highest interval index for each data channel in a coding value based on a mapping scheme. The method according to claim 10, characterized in that the plurality of intervals is assigned a plurality of indexes of intervals, and wherein the determination of location information for each of the plurality of data channels further comprises generating location information for each data channel to indicate a lower interval rate and a higher interval index used for the data channel. The method according to claim 5, characterized in that the determination of location information for each of the plurality of data channels further comprises generating location information for each data channel for a current superframe to indicate a length of each packet of data that is sent on the data channel in the current superframe. The method according to claim 1, characterized in that the generation of the overload information comprises generating a first portion of overload information with location information for data channels with a first coverage area, generating a second portion of information overload with location information for data channels with a second coverage area. 16. The method of compliance with claim 15, characterized in that the first coverage area is a wide coverage area and the second coverage area is a local coverage area. The method according to claim 15, characterized in that the transmission of the overload information comprises separately transmitting the first and second portions of the overload information in the first and second time intervals, respectively. The method according to claim 15, further characterized in that it comprises: processing the first portion of the overload information according to a first mode; processing the second portion of the overload information according to a second mode, wherein each of the first and second modes indicates a particular code rate and a particular modulation to be used for the overload information. The method according to claim 1, further characterized in that it comprises: forming at least one overload message for the overload information for the plurality of data channels, each overload message includes at least one location record, and each location record includes location information for a data channel associates The method according to claim 19, characterized in that the plurality of data channels are assigned different identifiers, and where the formation of at least one overload message comprises accommodating at least one location record for each overload message in sequential order based on identifiers of at least one associated data channel. 21. The method according to claim 19, characterized in that each location record has a fixed length. The method according to claim 5, further characterized by comprising: determining the location information for each data channel for a future superframe, the location information for data channel for the future superframe indicates the location of time, location frequency or both of the time and frequency location where the data channel is transmitted in the future superframe; and transmit the location of information for each data channel for the future superframe together with the data for the data channel in a current superframe. 23. An apparatus in a communication system, characterized in that it comprises: an operating controller for determining the location information for each of the plurality of data channels and for generating overload information with the location information for the plurality of data channels, the location information for each channel of data indicates the location of time, frequency location, or both of the time and frequency location where the data channel is transmitted; and an operational data processor for processing overload information for transmission in a time division multiplexed (TDM) form with the data for the plurality of data channels. The apparatus according to claim 23, further characterized in that it comprises: a transmitting unit operable to transmit the plurality of data channels in superframes, each superframe has a predetermined time duration and to further transmit the overload information in each superframe . 25. The apparatus according to claim 24, characterized in that the controller is also operative to determine the location information for each data channel for a future super-frame, the location information for each channel of data for the future superframe indicates the location of time, frequency location, and both of the time and frequency location where the data channel is transmitted in the future superframe, and where the data processor is also operational to process the location information for each data channel for the future superframe for transmission along with the data for the data channel in a current superframe. 26. The apparatus according to claim 23, characterized in that the communication system is a wireless broadcast system using orthogonal frequency division multiplexing (OFDM). 27. An apparatus in a communication system, characterized in that it comprises: means for determining the location information for each of plurality of data channels, the location information for each data channel indicates the time location, the frequency location , or both of the time and frequency location where the data channel is transmitted; means for generating the overload information with the location information for the plurality of data channels; and means to transmit the information of overload in a time division multiplexed (TDM) form with the data for the plurality of data channels. The apparatus according to claim 27, further characterized in that it comprises: means for transmitting the plurality of data channels in superframes, each superframe having a predetermined time duration, and wherein the overload information is transmitted in each superframe 29 The apparatus according to claim 28, further characterized in that it comprises: means for determining the location information for each data channel for a future super-frame, the location information for each data channel for the future super-frame indicating the time location , the frequency location, or both of the time and frequency location where the data channel is transmitted in the future superframe; and means for transmitting the location information for each data channel for the future superframe together with the data for the data channel in a current superframe. 30. A method for transmitting overload information in a communication system, characterized in that it comprises: transmitting a plurality of data channels in superframes, each superframe having a predetermined time duration, in each data channel carrying at least one data stream; determining the location information for each of the plurality of data channels, the location information for each data channels indicating the time location, the frequency location, or both of the time and frequency location where the channel data is transmitted in a future superframe; transmit the location information for each data channel together with data for the data channel in a current superframe. 31. The method according to claim 30, characterized in that the future superframe is a following superframe that immediately follows the current superframe. 32. The method according to claim 30, characterized in that the future superframe is more than one superframe of the current superframe. 33. The method according to claim 30, characterized in that the determination of the location information for each plurality of data channels comprises generating location information for each data channel to indicate whether the data channel is transmitted or not in the future superframe. 3
4. 4. The method according to claim 30, characterized in that the determination of the location information for each of the plurality of data channels comprises for each data channel that is transmitted in the future super-frame, generating the location information for the data channel to indicate a start time in which the data channel is transmitted in the future superframe. 3
5. 5. The method according to claim 30, characterized in that the determination of location information for each of the plurality of data channels comprises for each data channel not transmitted in the future superframe, generating location information for the data channel to indicate a next more superframe in the which is potentially transmitted the data channel. 3
6. 6. The method according to claim 30, characterized in that the transmission of the plurality of data channels comprises transmitting the plurality of data channels in a plurality of intervals, each interval being associated with a particular set of sub-bands and frequency. 3
7. 7. The method according to claim 36, characterized in that the plurality of intervals is assigned a plurality of interval indices, and wherein the determination of the location information for each of the plurality of data channels comprises for each channel of data that is transmitted in the future superframe, generate the location information for the data channel to indicate a lower interval index, a Home Interval index, and a higher interval index used for the data channel in the future superframe. 3
8. 8. The method according to claim 30, characterized in that the determination of the location information for each of the plurality of data channels comprises for each data channel that the future superframe is transmitted, generating the location information for the data channel to indicate a length of each data packet that is sent in data channel in the future superframe. 3
9. 9. An apparatus in a communication system, characterized in that it comprises: a transmitting unit operable to transmit a plurality of data channels in superframes, each superframe having a predetermined time duration, and each data channel carrying at least one data stream; an operating controller for determining the location information for each of the plurality of data channels, the location information for each data channel indicating the time location, the frequency location, or both of the time and frequency location where the data channel is transmitted in a future superframe, - an operational data processor for processing the location information for each data channel for transmission along with the data for the data channel in a current superframe. 40. In a communication system, characterized in that it comprises: means for transmitting a plurality of data channels in superframes, each superframe having a predetermined time duration, and each data channel carrying at least one data stream; means for determining the location information for each of the plurality of data channels, the location information for each data channel indicating the location of time, location of frequency or both of the time and frequency location where the data channel is transmitted in a future superframe; means for transmitting the location information for each data channel together with data for the data channel in a current superframe. 41. A method for receiving data in a communication system characterized in that it comprises: receiving overload information for a plurality of data channels transmitted in superframes, each superframe having a predetermined time duration, where the overload information for a current superframe is transmits in a time division multiplexed (TDM) form with data sent in the current super-frame for the plurality of data channels; obtain the first location information for a selected data channel from the overload information received in the current superframe, the first location information indicating the time location, the frequency location or both of the time and frequency location where the The selected data channel is transmitted in the current superframe, and - and receive the selected data channel in the current superframe based on the first location information. 42. The method of compliance with claimed 41, further characterized by comprising: processing the selected data channel to obtain the second location information for the selected data channel, second the location information is transmitted together with the data for the selected data channel in the current superframe e indicates the time location, the frequency location, or both of the time and frequency location where the selected data channel is transmitted in a future superframe; and receiving the selected data channel in the future superframe based on the second location information. 43. An apparatus in a communication system, characterized in that it comprises: an operating controller for receiving the overload information for a plurality of data channels transmitted in superframes, and for obtaining the first location information for a data channel selected from the Overload information received in a current superframe, each superframe has a predetermined time duration, the overload information for a current superframe that is transmitted in a time division multiplexed (TDM) form with data sent in the current superframe for plurality of data channels, and the first location information indicating the time location, the frequency location, or both of the time and frequency location where the selected data channel is transmitted in the current superframe; and an operational data processor for receiving the selected data channel in the current superframe based on the first location information. 44. The apparatus according to claim 43, characterized in that the data processor is further operable to process the selected data channel to obtain the second location information for the selected data channel, the second location information is transmitted together with the data for the selected data channel in the current superframe and indicates the time location, the frequency location, or both of the time and frequency location where the selected data channel is transmitted in a future superframe, and where the The data processor is further operative to receive the selected data channel in the future superframe based on the second location information. 45. An apparatus in a communication system, characterized in that it comprises: means for receiving the overload information for the plurality of data channels transmitted in superframe, each superframe having a predetermined time duration, where the overload information for a current superframe is transmitted in a time division multiplexed (TDM) form with data sent in the current superframe for the plurality of data channels; means for obtaining the first location information for a data channel selected from the overload information received in the current super-frame, the first location information indicating the time location, the frequency location or both of the time and frequency location where the selected data channel is transmitted in the current superframe; and means for receiving the selected data channel in the current superframe based on the first location information. 46. The apparatus according to claim 45, further characterized in that it comprises: means for processing the selected data channel to obtain the second location information for the selected data channel, the second location information is transmitted together with the data for the data channel selected in the current superframe and indicates the time location, the frequency location, or both of the time and frequency location where the selected data channel is transmits in a future superframe; means for receiving the selected data channel in the future superframe based on the second location information.