MXPA06004515A - Local and wide-area transmissions in a wireless broadcast network - Google Patents

Abstract

To broadcast different types of transmission having different tiers of coverage in a wireless broadcast network, each base station processes data for a wide-area transmission in accordance with a first mode (or coding and modulation scheme) to generate data symbols for the wide-area transmission and processes data for a local transmission in accordance with a second mode to generate data symbols for the local transmission. The first and second modes are selected based on the desired coverage for wide-area and local transmissions, respectively. The base station also generates pilots and overhead information for local and wide-area transmissions. The data, pilots, and overhead information for local and wide-area transmissions are multiplexed onto their transmission spans, which may be different sets of frequency subbands, different time segments, or different groups of subbands in different time segments. More than two different types of transmission may also be multiplexed and broadcast.

Description

"LOCAL AND BROAD AREA TRANSMISSIONS IN A WIRELESS EMISSION NETWORK" FIELD OF THE INVENTION The present invention relates in general terms to communication, and more specifically to the transmission of data in a wireless communication network.

BACKGROUND OF THE INVENTION Wired and wireless broadcast networks are widely deployed to provide diverse content to a large group of users. A common wired network is a cable network that sends multimedia content to a large number of households. A cable network typically includes central nodes and distribution nodes. Each central node receives programs from different sources, generates a separate modulated signal for each program, multiplexes the modulated signals for all programs into an output signal, and sends its output signal to the distribution nodes. Each program can be distributed across a large geographic area (for example, an entire state) or a smaller geographic area (for example, a city).

Each distribution node covers a specific area within the broad graphic area (for example, a community). Each distribution node receives the output signals from the central nodes, multiplexes the modulated signals for the programs to be distributed in its coverage area over different frequency channels, and sends its output signal to the households within its coverage area . The output signal for each distribution node typically carries both national and local programs, which are often sent by separate modulated signals that are multiplexed into the output signal. A wireless network of broadcasts transmits data via air to wireless devices within the area of coverage of the network. A wireless network of emissions is different from a wired network of emissions in various aspects. First, signals transmitted by different base stations in the wireless broadcast network interfere with each other if these signals are not the same. In contrast, the output signal of each distribution node is sent by dedicated cables and consequently does not suffer interference from other distribution nodes. Second, each base station in the wireless broadcast network typically transmits a single modulated radio frequency (RF) signal that carries data for all programs that are broadcast by that base station. In contrast, each distribution node in the wireless broadcast network can multiplex individual modulated signals for different programs in different frequency channels. Because of these differences, the techniques used to distribute programs in a wireline broadcast network are generally not applicable to a wireless broadcast network. Therefore, there is a need in the field for a wireless broadcast network that can efficiently broadcast different types of content with different coverage areas.

BRIEF DESCRIPTION OF THE INVENTION The present invention describes the techniques for emitting different types of transmissions (eg, local and wide area transmissions) in a wireless emission network. As used herein, "broadcast" and "broadcast" refer to the transmission of content / data to a group of users of any size and may also be referred to as "multi-broadcast" or with some other terminology. A wide area transmission is a transmission that can be broadcast by all or by many transmitters in the network. A local transmission is a transmission that can be issued by a subset of transmitters for a given wide area transmission. Different local transmissions can be issued by different subsets of the transmitters for a certain wide area. Different broad area transmissions can also be issued by different groups of transmitters in the network. An on-site transmission can also be issued by a smaller subset of a given subset of transmitters for a given local transmission. Broad-area transmissions, local and in situ can be visualized as different types of transmission that have different coverage rows, determining the coverage area for each transmission by all the transmitters that emit that transmission. Wide area, local and in-situ transmissions typically carry different content, but these transmissions can also carry the same content. At each base station (or transmitter) in the wireless broadcast network, the data for a wide area transmission is processed according to a first coding and modulation scheme (or "mode") selected for broad area transmission in order to to generate data symbols for broad area transmission. The data for a local transmission is processed according to a second coding and modulation scheme for local transmission in order to generate data symbols for local transmission. The first and second coding and modulation schemes can be selected based on the desired coverage from the base station for wide area and local transmissions, respectively. A time division multiplexed pilot (TDM - time division multiplexed) and / or a frequency division multiplexed pilot (FDM - frequency multiplexed division) used to recover local and wide area transmissions are generated. The supplementary information indicative of the time and / or frequency location of each data channel sent in the local and wide area broadcasts is also determined. The data channels carry multimedia content and / or other data that is sent in local and wide area broadcasts. The data, pilots, and complementary information for local and wide-area transmissions can be multiplexed in various ways. For example, the data symbols for broad-area transmission can be multiplexed in a "transmission interval" allocated for broad-area transmission, the data symbols for local transmission can be multiplexed in a transmission interval allocated for local transmission , the TDM and / or FDM pilots for broad-area transmission can be multiplexed in a transmission interval allocated for these pilots, and the TDM and / or FDM pilots for local transmission can be multiplexed in an assigned transmission interval for These pilots. The supplementary information for local and wide-area transmissions can be multiplexed into one or more intended transmission intervals. The different transmission intervals may correspond to (1) different sets of frequency sub-bands if the FDM is used by the wireless broadcast network, (2) different time segments if the TDM is used, or (3) different groups of sub-bands in different time segments if both TDM and FDM are used. Various multiplexing schemes are described below. They can also be processed, multiplexed, and issued more than two different types of transmission with more than two different rows of coverage.

A wireless device in the wireless emission network executes the supplementary processing to recover the data for local and wide-area transmissions. In the following, various aspects and embodiments of the invention are described in detail.

BRIEF DESCRIPTION OF THE DRAWINGS The characteristics and nature of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which the characters of similar references are correspondingly identified throughout the description. same and where: Figure 1 shows a wireless network of emissions; Figure 2A shows a coverage area for broad area transmission; Figure 2B our coverage area for different local transmissions; Figure 3A shows a structure of FDM for broadcasting broad area and local transmissions; Figure 3B shows emission transmissions using the FDM structure in Figure 3A; Figure 4A shows a TDM structure for broadcasting broad area and local transmissions; Figure 4B shows emission transmissions using the TDM structure in Figure 4A; Figure 5 shows a superframe structure to emit local and wide-area transmissions; Figure 6 shows the partition of data subbands into three separate sets; Figure 7 shows an FDM pilot for local and wide area transmissions; Figure 8 shows a process for broadcasting broad area and local transmissions; Figure 9 shows a process for receiving broad area and local transmissions; and Figure 10 shows a block diagram of a base station and a wireless device.

DETAILED DESCRIPTION OF THE INVENTION The words "by way of example" are used herein to refer to "which serves as an example, instance, or illustration." Any modality or design described herein "by way of example" does not necessarily have to be interpreted as being preferred or advantageous over other modalities or designs. Figure 1 shows a wireless network 100 of broadcasts that can emit different types of transmission such as, for example, broad-area transmissions and local transmissions. Each wide-area transmission is emitted by a set of base stations in the network, which can include all or many base stations in the network. Each wide area transmission is typically issued over a large geographic area. Each local transmission is issued by a subset of base stations in a given set for a given broad area transmission. Each local transmission is typically issued over a smaller geographic area. For simplicity, the large geographic area for a broad area transmission is also called a broad coverage area or simply a "broad area", and the smaller geographic area for a local transmission is also called a local coverage area or simply an "area" local". Network 100 may have a larger coverage area such as all of the United States, a large region of the United States (eg, western states), a whole state, and so on. For example, a single broad area transmission may be broadcast to the entire state of California, and different local broadcasts may be broadcast over different cities such as Los Angeles and San Diego. For simplicity, Figure 1 shows network 100 covering wide areas 110a and 110b, broad area 110a encompassing three local tasks 120a, 120b, and 120c. In general, the network 100 can include any number of broad areas with different broad area transmissions and any number of local areas with different local transmissions. Each local area can be linked to another local area or it can be isolated. Network 100 can also broadcast any number of different types of transmission designed for reception over geographical areas of any number of different sizes. For example, the network 100 may also emit an on-site transmission designed for reception over a smaller geographic area, which may be a portion of a certain local area. For the sake of simplicity, in the majority of the following description, network 100 is assumed to cover a single broad area and multiple local areas for two different types of transmission. Figure 2A shows the coverage area for broad area transmission in network 100. All base stations in a certain broad area emit the same broad area transmission, and the network is referred to as an individual frequency network (SFN). single frequency network). If all base stations in the local area emit the same wide area transmission, then a wireless device can combine the received signals from different base stations for improved performance. In a physical layer, the primary impairments to the reception of data in the SFN are thermal noise and performance degradation due to the variation of time and the dispersion of excessive delays of the wireless channel. The dispersion of delays of the time difference between the instance (or multipath) of the signal that arrives earlier and the signal instance that arrives later in the wireless device. Figure 2B shows the different coverage areas for different local transmissions in the network 100. The base stations in the different local areas transmit different local transmissions, and the network is referred to as a multiple frequency network (MFN). The terms "SFN" and "MFN" are broadcast terminology commonly used to describe the characteristics of a network, and MFN does not necessarily mean that the - In different base stations transmit by different radio frequencies. Although base stations in different local areas emit different local transmissions, a wireless device within a given local area may experience little compliant interference from base stations in neighboring local areas due to the relatively large distance to the base stations of interference. For example, the wireless device 1 in the local area A, the wireless device 4 in the local area B, and the wireless device became numerical 6 in the local area C may experience or have interference from neighboring local areas. The local transmission is essentially SFN type for these indoor wireless devices. A wireless device near the boundary of a local area may observe significant adjacent local channel interference (ALCI) from the signals transmitted by the base stations in neighboring local areas. For example, the wireless device 2 in the local area A may suffer a significant ALCI from base stations in the neighboring local areas B and C, the wireless device 3 in the local area B may suffer a significant ALCI from the base stations in neighboring local areas A and C, and wireless device 5 in local area C can suffer a significant ALCI from the base stations in the neighboring local areas A and B. The network is essentially of the MFN type for these peripheral wireless devices. The ALCI results in additional degradation of performance over the case of SFN. If the data is processed and transmitted in the same way for both the SFN and the MFN, then the ALCI observed by the peripheral wireless devices in the case of the MFN degrades the quality of the signal received in these wireless devices and causes a reduction in coverage at the border of neighboring local areas. In general, the coverage area for each type of transmission (for example, wide area or local) may correspond to the requirement of use seems type of transmission. A transmission with greater applicability can be sent by wireless devices in a larger geographical area. Inversely, a transmission with more limited applicability to wireless devices can be sent in a smaller geographic area.

The network 100 may be designed to provide good performance for both local and wide area broadcasts. This can be accomplished by doing the following: • Multiplex local and wide-area transmissions in the time, frequency and / or code domain so that interference between the two types of transmission is reduced; • Transmit local and wide-area transmissions (as well as their associated pilots) based on the different characteristics of MFN and SFN, respectively; and • Provide flexibility in the allocation of resources to meet the variable rate (source) demands of local and wide-area transmissions. Local transmissions are sent based on the characteristics of MFN in order to provide better coverage for wireless devices located at the edges of local areas. Broad area transmissions for different wide areas are also of the MFN type at the boundary between these broad areas and can also be sent using the techniques described herein. Each of the three aspects above is described in detail below. 1. Multiplex local and wide-area transmissions Figure 3A shows FDM structures 300 that can be used to broadcast local and wide-area transmissions over a given system bandwidth in a multi-carrier network. The FDM structure 300 supports the reception of both local and wide-area transmissions by a receiver tuned to a single radio frequency, and is different from a scheme that transmits local and wide-area transmissions using different radio frequencies. The general bandwidth of the system is divided into multiple (N) orthogonal frequency subbands using a multi-carrier modulation technique such as orthogonal frequency division multiplexing (OFDM) or by some other construction. These subbands are also called tones, carriers, subcarriers, groups and frequency channels. With the OFDM, each subband is associated with a respective subcarrier that can be modulated with the data. Of the N total subbands, U sub-bands can be used for data and pilot transmission and are called "usable" subbands, where U = N. The remaining G subbands are not used and are called "guard" subbands, where N = U + G. As a specific example, the network can use an OFDM structure with N = 4096 total subbands, U = 4000 usable subbands, and G = 96 guard subbands. In general, N, U and G can be any value. For simplicity, the following description assumes that all N subbands are usable for transmission, ie, U = N, and G = 0 so that there are no guard subbands. In each symbol period with the data transmission, P subbands of the N subbands usable for an FDM pilot can be used and are called "pilot" subbands, where P < N. A pilot is ethically composed of known modulation symbols that are processed and transmitted in the known manner. The remaining D usable subbands can be used for data transmission and are called "data" subbands, where D = N-P. A TDM pilot can also be transmitted in some symbol periods in the N usable sub-bands. For the modality shown in Figure 3A, an FDM pilot is transmitted in P pilot subbands that are distributed over the entire bandwidth of the system in order to provide a better sampling of the frequency spectrum. The D data subbands can be assigned to local transmission, wide area transmission, complementary information, etc. A set of Lsb subbands can be assigned for local transmission, and a set of Wsb subbands can be assigned for wide area transmission, where W? B + Lsb = D. The Wsb subbands for wide area transmission and the Lsb subbands for local transmission can be distributed over the entire bandwidth of the system in order to improve frequency diversity, as shown in Figure 3A. The Wsb subbands carry data for broad area transmission (or simply, wide area data) and the Lsb subbands carry data and for local transmission (or simply, local data). Figure 3B shows the transmission of data for different local areas using structure FDM 300. In order to minimize the interference between local and wide-area transmissions, all base stations in a given broad area can use the same set of Wsb subbands to broadcast broad-area transmission. The base stations in different local areas can emit different local transmissions in the set of Lsb subbands assigned to the local transmissions. The number of sub-bands allocated for local and wide-area transmissions may vary based on the requirements of the resources. For example, Wsb and Lsb may vary (1) dynamically from symbol to symbol or from time interval to interval of time, (2) based on the time of day, day of the week, etc., (3) based on a specific agenda, or (4) based on any combination of the above. For example, Wsb and L? B may vary dynamically during a portion of each "day of the week, may be fixed during the remaining portion of each day of the week, and be adjusted based on a predetermined day of the week schedule. In order to simplify the allocation of resources and improve frequency diversity, the N usable subbands can be configured in M "interlaced" or sets of separate subbands.The M interleaved are separated because each of the N usable subbands belong only to one interlaced Each interlaced contains P usable subbands, where N-M'P The P subbands in each interlacing can be distributed uniformly in the N usable subbands such that the consecutive subbands in each interlacing are spaced by M subbands. of OFDM by way of example described above, M = 8 interlaced can be formed, each interlaced containing P = 512 subbands utili zables that are evenly spaced by 8 subbands. Consequently, the P subbands that can be used in each interlacing are interlaced with the P subbands that can be used in each of the other interlaced M-ls. As an example, an interleaving scheme and OFDM structure has been described above. Other OFDM structures and subband allocation schemes can also be used to support the FDM of local and wide-area transmissions. Figure 4A shows a TDM structure 400 that can also be used to broadcast local and wide-area transmissions in a single-carrier or multi-carrier network. The transmission timeline is divided into frames 410, each frame having a predetermined duration. The frame length can be selected based on various factors such as, for example, the amount of time diversity desired for data transmission. Each frame includes a field 412 that carries its pilot and complementary information, a segment 414 that carries wide-area data, and a segment 416 that carries local data. Each frame can also include other fields for other information.

Figure 4B shows the data transmissions for different local areas using the TDM structure 400. In order to minimize the interference between local and wide-area transmissions, the wide-area segment 414 for all base stations in a given broad area may be aligned in time such that these base stations broadcast broad-area transmission to the Same time. Base stations in different local areas can broadcast different local transmissions in segment 416. The sizes of segments 414 and 4161 can vary dynamically or by default based on the requirements of the resources. For the FDM structure 300 in Figure 3A and the TDM structure 400 in Figure 4A, the broad area and local transmissions are multiplexed in frequency and time, respectively, in such a way that the two transmission types overlap one minimally to another . This alignment prevents or minimizes the interference between the two types of transmission. However, strict adherence to the non-overlap of different types of transmission is not necessary. In addition, different local areas may have different frequency or time assignments. In general, various multiplexing structures can be used to emit different types of transmission with different coverage areas. Next, a specific multiplexing structure suitable for a wireless broadcast network based on OFDM is described. Figure 5 shows an exemplary superframe structure 500 that can be used to broadcast local and wide area broadcasts in an OFDM-based wireless broadcast network. Data transmission occurs in superframe 510 units. Each superframe expands a predetermined duration, which can be selected based on various factors such as, for example, the desired statistical multiplexing for data streams that are issued, the amount of time diversity desired for the data streams, the acquisition time for the data streams, the temporary memory requirements for the wireless devices, etc. A superframe size of about one second can provide a good balance between the various factors observed previously. However, other superframe sizes may also be used. For the embodiment shown in Figure 5 each superframe 510 includes a header segment 520, four frames of the same size 530a to 530d, and a pull segment 540, which are not shown in Figure 5. Table 1 list the various fields for the segments 520 and 540 and for each frame 530.

Table 1 For the modality shown in Figure 5, different pilots are used for different purposes. A TDM pilot is transmitted at or near the start of each superframe and can be used for the purposes noted in Table 1. A transition pilot is sent at the boundary between the local / wide area fields / transmissions allowing the transition no stitches between local / broad area fields / transmissions, and can be generated as described below.

Local and wide-area transmissions can be for multimedia content in such as video, audio, teletext, data, video / audio extracts, etc., and can be sent by separate data streams. For example, a single multimedia program (eg, television) can be sent in three separate data streams for video, audio, and data. The data flows are sent by data channels. Each data channel can carry one or multiple data streams. A data channel that carries data streams for a local transmission I have also called "local channel", and a data channel that carries data streams for broad area transmission is also called "wide area channel". The local channels are sent in the Local Data fields and the wide area channels are sent in the Wide Area Data fields of the super-frame. Each data channel can be "assigned" a fixed number or interlaced variable in each superframe depending on the payload for the data channel, the availability of interlaced in the super-frame, and possibly other factors. Each data channel can be active or inactive in any given superframe. Each active data channel is assigned at least one interleaving. Each active data channel is also "assigned" to specific interleaves within the superframe based on an allocation scheme that attempts to (1) package all active data channels as efficiently as possible, (2) reduce the transmission time for each data channel, (3) provide an adequate time diversity for each data channel, and (4) minimize the amount of signaling necessary to indicate the interleaves assigned to each data channel. For each active data channel, the same interleaving assignment can be used for the four frames of the superframe. The OIS Local field indicates the time-frequency assignment for each active local channel for the current super-frame. The OIS field of Local Area indicates the time-frequency assignment for each wide-area active channel for the current super-frame. The Local OIS and Wide Area OIS are sent at the start of each superframe to allow the wireless devices to determine the time-frequency location of each data channel of interest in the superframe. The various fields of the superframe may be sent in the order shown in Figure 5 or in some other order. In general, it is desirable to send the TDM pilot and complementary information initially in the superframe so that the TDM pilot and the supplementary information can be used to receive the data that is subsequently sent in the superframe. Broad area transmission can be sent before local transmission, as shown in Figures 4A and 5, or after local transmission. Figure 5 shows a structure in specific superframe. In general, a superframe can expand any duration and can include any number and any type of segments, frames, and fields. However, there is usually a useful range of superframe durations related to the acquisition time and recycling time for the receiving electronics. Other frame and superframe structures may also be used to emit different types of transmission, and this is within the scope of the invention. Time division multiplexing of local and wide-area transmissions, as shown in Figure 5, allows broad area transmission to enjoy the advantages of OFDM within an SFN context, without interference from transmissions local. Since only local or wide-area transmission is sent at any given time with the TDM, local and wide-area transmissions can be issued using different transmission parameters that can be optimized independently to achieve good performance for local and wide-area transmissions , respectively, as described below. 2. Data Transmission The area channels that are issued in each superframe can be packaged as efficiently as possible. All base stations in a given broad area emit the same wide area transmission in the four Wide Area Data fields of each superframe. Then, a wireless device can combine the broad-area transmissions received from any number of base stations in order to improve the data reception performance. The base stations in different local areas emit different local transmissions in the four Local Data fields of each super-frame. A peripheral wireless device located near the boundary of neighboring local areas would then exhibit adjacent local channel interference (ALCI), which degrades the signal quality received in the device. The received signal quality can be quantified by a noise-by-signal-interference ratio (SINR) or some other measurement. The peripheral wireless device would achieve a lower SINR due to degradation to the ALCI. In a base station, data for local transmission is processed with a coding and modulation scheme that requires a particular SINR for proper reception. The ALCI has the effect of shrinking the local area since a given wireless device can achieve the required SINR in a smaller area in the presence of the ALCI. Various techniques can be used to improve coverage for local transmission. These techniques typically balance performance within the local area in order to extend coverage at the boundary. These techniques include partial loading and coding / modulation selection. With partial load, which is also called frequency reuse, not all usable subbands for data transmission are used to transmit data. In addition, sub-bands can be assigned to neighboring local areas in such a way that their local transmissions also interfere as possible with one another. This can be achieved with orthogonal partial load or random partial load. With orthogonal partial load, the neighboring local areas are assigned separate or non-superimposed sets of subbands. Then, the base stations in each local area allow local transmission by the set of subbands assigned to that local area. Since the sets of subbands are separated, the wireless devices in each local area do not present ALCI from the base stations in neighboring local areas. Figure 6 shows an exemplary partitioning of the D data subbands into three separate sets labeled as Si, S2 and S3. In general, each set can contain any number of data sub-bands and any of the D data sub-bands. Subbands for each set can also change dynamically or by default. To achieve frequency diversity, each set can contain subbands taken from the D data subbands. The subbands in each set can be distributed uniformly or non-uniformly in the D sub-bands of data. Referring again to Figure 2B, the local area A can be assigned the set of subbands Si, the local area B can be assigned the set of sub-bands S2, and the local area C can be assigned the set of sub-bands S3. Then, the base stations in the local area A emit the local transmission for the local area A by the set of subbands Si, the base stations in the local area B emit the local transmission for the local area B by the set of subbands S2, and the base stations in the local area C emit the local transmission for the local area C by the set of sub-bands S3. Figures 2B and 6 show a case with three local areas. The orthogonal partial load can be extended to any number of local areas. Q sets of separate subbands can be formed for Q neighboring local areas, where Q >;1. The Q sets may contain the same or different number of subbands. For the interleaving scheme described above, the interleaved M-ls available for data transmission can be assigned to the Q sets. Each set can contain any number of interlaces. The interlaces to each set can change dynamically or by default. Each local area is assigned a respective set of interlaces for local transmission. Frequency planning can be done on all people to ensure that neighboring local areas are assigned separate sets. With the partial random load, each local area is assigned K subbands of data, where K < D, and the base station because the local area emits the local transmission by K subbands selected in a pseudo-random way from among the D data subbands. For each local area, a pseudo-random number generator (PN) can be used to select a different set of K in each symbol period. Different local areas can use different PN generators so that the sub-bands used by each local area are pseudo-random with respect to the sub-bands used by neighboring local areas. In effect, the local transmission for each local area jumps in the D data subbands. The ALCI occurs at any time a collision occurs and the neighboring local areas use the same subbands in the same symbol period. However, the ALCI is randomized due to the pseudo-random manner in which the K sub-bands are selected in each symbol period for each local area. A wireless device is aware of the jumps made by the base stations and can execute the complementary de-jump to recover the local transmission. For partial load of any kind, the transmission power for each subband used for data transmission can be increased without increasing the total transmission power. The total transmit power can be distributed over the K subbands used for local transmission in each period of symbols, which can be called "active" subbands. If K subbands are used for local transmission and D subbands are used for wide area transmission, where K < D with partial load, then the transmission power per active subband is greater for local transmission than for wide area transmission. The signal quality received by active subband is consequently higher with partial load, which improves the noise ratio per signal for the subband in the receiver. Orthogonal and partial random loading can be performed for data-only sub-bands, pilot-only sub-bands, or both data and pilot sub-bands. Orthogonal and partial random loading can improve coverage at the expense of lower overall performance. This is because fewer subbands are used for data transmission with partial load, and fewer bits of information can be sent in each symbol period by these fewer subbands. The number that subbands to use for local transmission can be selected based on a balance between improved coverage and overall performance. The network can support a set of transmission modes, or simply "modes". Each mode is associated with a particular coding scheme or code rate, a particular modulation scheme, a particular spectral efficiency, and a particular minimum SINR required to achieve a specific level of performance, for example, a packet error rate. (PER - packet error rate) at 1% for an AWGN channel without fading. The spectral efficiency can be determined in units of information bits per modulation symbol and is determined based on the code rate and the modulation scheme. In general, modes with lower spectral efficiencies have lower required SINRs. For each mode, the required SINR can be obtained based on the specific system design (such as the code rate, the distribution scheme, and the modulation scheme used for that mode) and for a particular channel profile. The required SINR can be determined by computer simulation, empirical measurements, and so on. The coverage area for a local transmission can be adjusted by selecting an appropriate mode to use the local transmission. A mode with a lower required SINR can be used for local transmission in order to extend coverage near the boundary of neighboring local areas. The particular mode for using the local transmission can be selected based on a balance between improved coverage and spectral efficiency. The coverage for a wide area transmission can be adjusted in a similar way by selecting an appropriate mode to use wide area transmission. In general, the same or different modes can be used for local and wide-area transmissions. Coverage for local transmission can be improved with partial load and / or mode selection. Coverage can be extended by using a lower percentage of usable subbands and / or by selecting a mode with lower spectral efficiency. A rate (R - rate) of information bits can be expressed as: R =? * K, where? is the spectral efficiency for the selected mode and is the number of active subbands. A given information bit rate can be achieved by using (1) a subset of all the data sub-bands and a mode with a higher spectral efficiency or (2) all the data sub-bands and a mode with a lower spectral efficiency. It can be seen that option (2) can provide better performance (for example, wider coverage for a given PER) than option (1) for some operational scenarios (for example, for random partial loading and without interference calculations) ). 3. Pilot Transmission Figure 7 shows a pilot transmission scheme that can support both local and wide-area transmissions. For simplicity, Figure 7 shows the pilot transmission for a superframe frame. Each base station transmits the transition pilot between local and wide-area fields / transmissions. Each base station transmits also the FDM pilot could interleaved in each symbol period with data transmission. For the embodiment shown in Figure 7, eight interleaves are available in each symbol period, and the FDM pilot is transmitted by interleaving 3 in period indices of even-numbered symbols and by interleaving 7 in period indexes of odd numbered symbols, which may be noted as an alternating pattern. { 3, 7.}. . The FDM pilot can also be transmitted with other alternating patterns such as, for example, patterns. { 1, 2, 3, 4, 5, 6, 7, 8.}. Y . { 1, 4, 7, 2, 5, 8, 3, 6.}. . As shown in Figure 7, the FDM pilot is transmitted during wide area transmission as well as during local transmission. The FDM pilot can be used to derive (1) a channel calculation for broad area transmission, which is also called wide area channel calculation, and (2) a channel calculation for local transmission, which is also called local channel calculation. Local and wide-area channel calculations can be used for the detection and decoding of data for local and wide-area transmissions, respectively. The FDM pilot transmitted during wide-area transmission is called a wide-area FDM pilot and may be designed to facilitate the calculation of wide-area channel. The same wide-area FDM pilot can be transmitted throughout the wide area. The FDM pilot transmitted during the local transmission is called the local FDM pilot and may be designed to facilitate the local channel calculation. Different local FDM pilots can be transmitted to different local areas in order to allow wireless devices to obtain local channel calculations for different local areas. The different local FDM pilots interfere with each other in the border of the local neighboring areas, similar to the ALCI for the different local transmissions. Local FDM pilots can be designed in such a way that a good local channel calculation can be dedicated in the presence of pilot interference from neighboring local areas. This can be achieved by orthogonalizing or randomizing the local FDM pilots for different local areas in frequency, time, and / or code domain, as described below. Figure 7 also shows a modality of the FDM pilot. A set of P modulation symbols is used for the P pilot sub-bands for the local FDM pilot. The P modulation symbols can be multiplied with a first sequence of complex values in frequency and / or a second sequence of complex values in time to generate the pilot symbols for the local FDM pilot. The first sequence is denoted as. { S (k)} r where S (k) is the complex value for subband k. The second sequence is denoted as. { C (n) } , where C (n) is the complex value the symbol period n. Different characteristics can be obtained for the local FDM pilot using different types of first and second sequences. A PN generator can be used to generate the first sequence of complex values. The PN generator can be a linear feedback shift register (LSFR) that implements a second polynomial generator, for example, g (x) = x15 + x14 + 1. The PN generator is initialized in a particular seeding value (or initial state) at the beginning of each symbol period and generating a sequence of pseudo-random bits. These bits are used to form the complex values for the first sequence. The pilot symbols for the local FDM pilot for a given local area can be expressed as: P (k, n) = S (k) - C (n), Eq. (1) where P (k, n) is the pilot symbol for subband k in symbol period n. Equation (1) assumes that the modulation symbols used for the local FDM pilot have values of 1 + '0. The pilot symbols received in a wireless device can be expressed as: Y (k, n) = H (k, n) • P (k, n) + HX (k, n) -P_ (k, n) + w ( k, n), Eq. (2) where P (krn) is a pilot symbol sent by the subband k in period of symbols n by a base station in a desired local area (ie, the desired base station); H (krn) is a current channel response for the desired base station; P? (k, n) is a pilot symbol sent by subband k in the period of symbols n by an interference base station in a neighboring local area; H? (k, n) is a current channel response for the interference base station; Y (k, n) is a pilots symbol received for subband k in the period of symbols n; and vr (krn) is noise for subband k in symbol period n. For simplicity, equation (2) assumes the presence of a desired base station and an interference base station, which is denoted by the subscript I. Local FDM pilots for different local areas can also be orthogonalized and / or randomized in the code domain using different orthogonal and / or pseudo-random sequences, respectively, for these local FDM pilots. Various code orthogonalization / scrambling techniques can be used for local FDM pilots, including orthogonal encryption, random encryption, and orthogonal and random encryption. For orthogonal encryption, local FDM pilots for different local areas are multiplied with orthogonal sequences in the symbol periods. The pilot symbols for the desired local and interference areas can then be expressed as: P (k, n) = S (k) - C (n) and Px (k, n) = S (k) • Cx (n) , Eq. (3) where. { C (n) } is orthogonal a. { C? (n) } . As shown in equation (3), the same PN sequence is used to generate the first sequence of complex values. { S (k)} both for desired areas and for local areas of interference. However, different orthogonal sequences are used. { C (n) } Y . { Cx (n) } both for desired areas and for local areas of interference.

A wireless device can derive a local channel calculation by first obtaining a complex channel gain calculation for each pilot subband used for the local FDM pilot, as explained below: ñP (k) = P (k, n) / S (k). Eq. (4) Equation (4) eliminates the effects of the PN sequence on the pilot sub-bands, which is also called decryption. The wireless device obtains P channel gain calculations for P uniformly distributed pilot subbands. The wireless device then executes an inverse discrete Fourier transform of P points (IDFT) for the P gain calculations in order to obtain a least squares impulse response calculation of P derivations, which can be expressed as: ñ os (l, n) = h (l) - C (n) + h? (l) • C_ (n) + w (1, n), Eq. (5) where 1 is an index for the V channel derivations of the impulse response calculation; h (1) is the current impulse response of for the desired base station; hj (l) is the current impulse response for the interference base station; F? os (l, n) is the least squares response calculation for symbol period n, where the subscript "os" denotes orthogonal encryption; and w (l, n) is the noise in the symbol period n. Equation (5) assumes that the current channel impulse response for each base station is constant for the duration of interest, so that h (l) and h? (l) are not functions of the period of symbols n. Then, a pulse response calculation h os (l) for the desired local area can be obtained by filtering the least squares impulse response calculations for different symbol periods, as explained below: = h (I) + W (I, n), Eq. (6) (-l) / 2 £ cr (n) -C '(«) = 0 where' = -a -? / 2 since C (n) and Cx (n) are orthogonal sequences; W (l,?) Is the post-processed noise; and L is the length of the orthogonal sequences (for example, L = 3). The sum index in equation (6) is for an odd value of L and different for a value of L. A wireless device located within the local area of interference can derive a calculation of impulse response ít 0s ,? (l) for that local area by multiplying h. os (l f n) with C *? (n) and integrate for the duration of the orthogonal sequence. As shown in equation (6), orthogonal encryption can cancel the pilot interference from the neighboring local area. However, this orthogonality can be disturbed due to channel time variations. Orthogonal sequences can be defined in various ways. In one embodiment, orthogonal sequences are defined as follows: C (n) = ly Cx (n) = ej2p'n / L, for __ = 0 ... (L-1) Ec (7) For the Random encryption, the pilot symbols for the desired local area are pseudo-random with respect to the pilot symbols for the local area of interference. Pilot symbols can be considered independently and identically distributed (i.i.d. - independently and identically distributed) in time, frequency, and local areas. The symbols of pseudo-random pilots can be obtained by initializing the PN generators for different local areas with different seeding values that are dependent on the period of symbols n and the local area identifier. For random encryption, a least squares impulse response calculation ñ rs (l) can be obtained by performing the (1) decryption as shown in equation (4) in order to eliminate the PN sequence for the desired local area , (2) post processing to obtain P gain channel calculations, and (3) an IDFT for the P gain channel calculations, as described above. The least squares impulse response calculation can be expressed as: h rB (l) = h (l) + gx (l, n) + w (l, n), Eq. (8) where g? (l, n) is the interference to the 2-th derivation of fi rs (l) and the subscript "rs" denotes random encryption. The interference gt (l, n) is a result of the channel impulse response ht (l) for the local area of interference that is covered in the P derivations of f? re (l) by PN sequences for local and local interference areas. The least squares impulse response calculation can be used directly as the impulse response calculation for the desired local area. The Equation (8) indicates that random encryption only covers (and does not suppress or cancel) pilot interference from the neighboring local area. Thresholds can be made to retain channel derivations that exceed a predetermined threshold and zero the channel derivations below the predetermined threshold. The thresholds can eliminate most of the pilot interference and can provide performance that is comparable to that achieved with orthogonal encryption. In addition, with random encryption, channel calculation performance is not lake-dependent orthogonality and may be more robust in some operating environments. For orthogonal and random encryption, the local FDM pilots for different local areas multiply with different PN sequences in subbands and multiply additionally with different orthogonal sequences in symbol periods. The pilot symbols for the desired local and interference areas can be expressed as: P (k, n) = S (k) - C (n) and Px (k, n) = Sx (k) - Cx (n), Ec. (9) where. { S (k)} Y . { Sx (k)} they are different pseudo-random sequences, and. { C (n) } Y . { Cx (n) } they are different orthogonal sequences. For orthogonal and random encryption, a least squares impulse response calculation n or (l rn) can be obtained by performing the processing described above for orthogonal encryption. The least squares impulse response calculation can be expressed as: h or (ln) = h (l) • C (n) + gx (l) • Cx (n) + w (1, n), Eq. (10 ) where the subscript "or" in denotes orthogonal and random encryption. A calculation of impulse response h OS (l) for the desired local area can be obtained by multiplying h or: (l rO.) With C * (n) and integrating for the duration of the orthogonal sequence, as shown in the equation (6) The impulse response of sampled channel for each area (local or wide) contains up to N leads, where N = M-P. The channel impulse response can be visualized by being composed of a main channel and an excess channel. The main channel contains the first P derivations of the channel impulse response. The excess channel contains the remaining N-P derivations. If the FDM pilot is transmitted by an interleaved with P subbands, then a pulse response calculation Ti os (1), T? rs (l), or h or (l) with P derivations based on the received FDM pilot. In general, the length of the impulse response calculation is determined by the number of different bands for the FDM pilot. A larger channel impulse response calculation with more than P leads can be obtained by transmitting the FDM pilot by more interleaves. For example, the FDM pilot can be transmitted by two different interlaces in different symbol periods, as shown in Figure 7. The techniques for deriving the coefficients of the time domain filters for the main and excess channels are described in U.S. Patent Application Serial Number 10 / 926,884, entitled "Stepped Pilot Transmission for Channel Calculation and Time Recording" ("Staggered Pilot Transmission for Channel Stress and Time Tracking"), filed on 25 August 2004. Different channel calculations can be obtained for the local and wide areas. A wireless device to receive signals from the base stations that are more removed for wide area transmission than for local transmission. Consequently, the delay spread for broad area transmission may be greater than the delay spread for local transmission. A larger channel impulse response calculation can be derived (for example, with a length of 3P) for the wide area. A smaller channel impulse response calculation (for example, with a length of 2P) can be derived for the local area. A larger impulse response calculation for the wide area can be obtained by using more interleaves for the FDM pilot for the wide area. Alternatively, the same number of interleaves can be used for FDM pilots for both local and wide areas, and different time domain filters can be used for local and wide areas. The least-squares impulse response calculations for the wide area can be filtered with a first set of one or more filters in the time domain in order to derive a filtered impulse response calculation with the desired number of derivations (e.g., 3P derivations) for the wide area. The least squares impulse response calculations for the desired local area can be filtered with a second set of filters in the time domain in order to derive a filtered impulse response calculation with the desired number of derivations (eg, 2P leads). ) for the desired local area. In general, time domain filtering for channel calculation can be performed based on various considerations such as, for example, the manner in which the FDM pilot is transmitted, the number of interleaves used for the FDM pilot , the desired length (or the number of derivations) for the calculation of channel impulse response, interference suppression, and so on. Time domain filtering can be done differently by FDM pilots for local and wide areas in order to obtain different filtered channel response calculations for local and wide areas. The filtered impulse response calculation for a certain area (local or wide) can be post-processed in order to further improve the performance. The post-processing could include, for example, adjusting the last Z derivations to zero, where Z can be any integer value, adjusting the derivations with the energy below a predetermined threshold at zero (thresholds), and so on. Post-processed channel derivations can not be transformed with a DFT to obtain the final sequence response calculation used for the detection and decoding of data. No Referring again to Figure 5, the transition pilot can be used for channel calculation, site synchronization, acquisition (for example, automatic gain control (AGC), etc.). For example, the transition pilot may include the FDM pilot so that the time domain filtering for each symbol period may be performed by the received pilot symbols obtained for the current symbol period, at least one period of symbols above, and at least one subsequent symbol period. The transition pilot can also be used to obtain improved synchronization for local transmission as well as wide area transmission. 4. Transmission and reception of emission Figure 8 shows a flow chart of a process 800 to be broadcast local and wide-area transmissions in the network 100. Each base station in the network can execute the process 800 in each programming interval, which can be, for example, each symbol period for the FDM structure 300 in Figure 3A, each frame for the TDM structure 400 in Figure 4A, or each superframe for the superframe structure 500 in Figure 5 The data for a wide-area transmission is processed according to a first scheme (or mode) of coding and modulation selected for broad-area transmission at the generation end and data symbols at each broad-area transmission (block 812). ). The data for a local transmission is not processed according to a second coding and modulation scheme selected for local transmission in order to generate data symbols for local transmission (block 814). Different coding and modulation schemes can be used for local and wide-area transmissions in order to achieve the desired coverage. The complementary information is determined for local and wide-area transmissions (blocks 816 and 818). The FDM pilot for the wide area is generated, the FDM pilot for the local area, and the transition pilot (blocks, 822, 824, and 826, respectively). The complementary information for wide area transmission and complementary information for local transmission are multiplexed for their designated transmission intervals (blocks 832 and 834). The data symbols for broad-area transmission are multiplexed for a transmission interval allocated for broad-area transmission (block 836) and the pilot symbols for the pilot Wide area FDMs are multiplexed for a transmission interval allocated for this pilot (block 838). Similarly, the data symbols for the local transmission are multiplexed for a transmission interval allocated for local transmission (block 840), and the pilot symbols for the FDM pilot are multiplexed for a transmission interval allocated for this pilot (block 842). Each transmission interval may correspond to a group of subbands (for example, for structure FDM 300), a time segment (e.g., for structure TDM 400), a group of subbands in a time segment (eg. example, for superframe structure 500), or some other time-frequency assignment. The TDM and transition pilots, other signaling, and other data can also be multiplexed (block 844). The multiplexed supplementary information, pilots, and data are then broadcasted for local and wide-area transmissions (block 846). Figure 9 shows a flow diagram of a process 900 for receiving broad area and local broadcasts emitted by the network 100. A wireless device in the network can execute the process 900 in each programming interval. The wireless device receives an emission transmission with both local and wide area broadcasts (block 912). The wireless device processes the TDM pilot in order to obtain synchronization of frames and symbols, calculate and correct the frequency error, etc. (block 914). The wireless device identifies the wide area and local channels that are served using the WIC and the LIC, which are shown in Figure 5 (block 916). After that, the wireless device can recover local transmission, wide area transmission, or both local and wide area transmissions from the received transmission of emissions. If the wireless device is receiving wide area transmission, as determined in block 920, then the wireless device demultiplexes and processes the complementary information for transmission of wide area in order to determine the time-frequency location of each wide-area channel of interest (block 922). The wireless device also demultiplexes and processes the wide area FDM and the transition pilots from the assigned transmission ranges for these pilots (block 924) and derives a channel calculation for the wide area (block 926). The wireless device demultiplexes the data symbols for wide area channels of interest from the transmission range allocated for wide area transmission (block 928). After, the wireless device processes the data symbols for broad area transmission with the wide-area channel calculation and further in accordance with a demodulation and decoding scheme applicable for wide-area transmission and retrieves the data for each area channel broad of interest (block 930). If the wireless device is receiving local transmission, as determined in block 940, then the wireless device demultiplexes and processes the complementary information for local transmission in order to determine the time-frequency location of each local channel of interest ( block 942). The wireless device also demultiplexes and processes the local and transition FDM pilots from the assigned transmission ranges for these pilots (block 944) and derives a channel calculation for the desired local area (block 946). The wireless device demultiplexes the data symbols for the local channels of interest from the transmission interval allocated for local transmission (block 948). Then, the wireless device processes the data symbols for local transmission with the local channel calculation and further in accordance with a demodulation and decoding scheme applicable for local transmission and retrieves the data for each local channel of interest (block 950) . If the wireless device is receiving both local and wide area transmissions, then the wireless device can perform the processing in a different order than the order shown in Figure 9. For example, the wireless device can demultiplex and process the complementary information both for local transmissions as wide area as this information is received.

. System Figure 10 shows a block diagram of a base station 1010 and a wireless device 1050 in the wireless network 100 of emissions in Figure 1. The base station 1010 is generally a fixed station and can also be referred to as an access point, transmitter, or with some other terminology. The wireless device 1050 may be fixed or mobile and may also be referred to as the user terminal, mobile station, receiver, or some other terminology. The wireless device 1050 can also be a portable unit such as a cell phone, a portable device, a wireless module, a personal digital assistant (PDA), etc. At the base station 1010, a transmission data processor 1022 (TX) or receive data for a wide area transmission from the sources 1012, processes (e.g., codes, distributes, and maps symbols) the wide area data, and generates data symbols for broad-area transmission. A data symbol is a modulation symbol for the data, and a modulation symbol is a complex value for a point in a signal constellation for a modulation scheme (for example, M-PSK, M-QAM, etc.). The TX data processor 1022 also generates the FDM and transition pilots for the wide area to which the base station 1010 belongs and provides the pilots data and symbols for the wide area to a multiplexer (Mux) 1026. A The TX data processor 1024 receives the data for a local transmission from the sources 1014, processes the local data, and generates data symbols for local transmission. The TX data processor 1024 also generates the FDM and transition pilots for the local area to which the base station 1010 belongs and provides the pilot data and symbols for the local area to the multiplexer 1026. The coding and modulation for the data can be selected based on various factors such as, for example, whether the data is for 5. a broad or local area transmission, the type of data, the desired coverage for the data, etc. The multiplexer 1026 multiplexes the pilot data and symbols for the local and wide areas as well as the symbols for the complementary information 0 and the TDM pilot by the sub-bands and symbol periods allocated for these symbols. A Modulator (Mod) 1028 performs the modulation according to the modulation technique used by the network 100. For example, the modulator 1028 can perform the OFDM modulation on the multiplexed symbols to generate the OFDM symbols. A transmitter unit (TMTR) 1032 converts the symbols of the modulator 1028 into one or more analog signals and also conditions (eg, amplifies, filters, and overconverts at 0 frequency) the analog signal (s) to generate a modulated signal. The base station 1010 then transmits the signal modulated by an antenna 1034 to the wireless devices in the network. On the wireless 1050 device, the signal 5 transmitted from the base station 1010 is received by an antenna 1052 and is provided to a receiving unit (RCVR) 1054. The receiving unit 1054 conditions (for example, filters, amplifies, and subverts in frequency) the received signal and digitizes the conditioned signal to generate a flow of data samples. A demodulator (De od) 1060 performs (e.g., OFDM) the demodulation in the data samples and provides the received pilot symbols to a sync 1080 / channel calculation unit 1080. The unit 1080 also receives the data samples from the receiving unit 1054, determines the synchronization of frames and symbols based on the data samples, and derives the channel calculations for the local and wide areas based on the pilot symbols received for these areas. The unit 1080 provides symbol synchronization and channel calculations to the demodulator 1060 and provides frame synchronization to the demodulator 1060 and / or a controller 1090. The demodulator 1060 performs data detection on the data symbols received for the transmission local with the local channel calculation, performs data detection on the received data symbols for wide area transmission with the wide-area channel calculation, and provides detected data symbols for local and wide-area transmissions to a demultiplexer (Demux) 1062. The detected data symbols are calculations of the data symbols sent by the base station 1010 and can be provided in logarithmic probability rates (LLR - log-likelihood ratios) or in some other form. The demultiplexer 1062 provides detected data symbols for all wide-area channels of interest to a reception data processor (RX) 1072 and provides detected data symbols for all local channels of interest for an RX data processor 1074. The RX data processor 1074 processes (eg, groups and decodes) the detected data symbols for wide area transmission according to a demodulation and decoding scheme and provides decoded data for wide area transmission. The RX data processor 1074 processes the detected data symbols for local transmission according to an applicable demodulation and decoding scheme and provides decoded data for local transmission. In general, processing by demodulator 1060, demultiplexer 1062, and RX data processors 1072 and 1074 in wireless device 1050 is complementary to processing by modulator 1028, multiplexer 1026, and data processors of TX 1022 and 1024, respectively, in the base station 1010. The controllers 1040 and 1090 direct operation in the base station 1010 and the wireless device 1050, respectively. Memory units 1042 and 1092 store program and data codes used by controllers 1040 and 1090, respectively. A 1044 programmer programs the broadcasts of local and wide-area transmissions and allocates and distributes resources for the different types of transmission. For clarity, Figure 10 shows the data processing for local and area transmissions that are carried out by two different data processors in both the base station 1010 and the wireless device 1050. Data processing for all types The transmission can be performed by a single data processor in each base station 1010 and the wireless device 1050. Figure 10 also shows processing for two different types of transmission. In general, any number of transmission types with different coverage areas can be transmitted by the base station 1010 and be received by the wireless device 1050. For clarity, Figure 10 also shows the units for the base station 1010 located at the same site. In general, these units can be located in the same or different sites and can communicate through various communication links. For example, the data sources 1012 and 1014 may be located off-site, the transmitter unit 1032 and / or the antenna 1034 may be located at a transmission site, etc. The multiplexing schemes described herein (e.g. Figures 3A, 4A, and 5) have various advantages over a conventional scheme that emits different types of transmission by different RF channels. First, the multiplexing schemes described herein may provide more frequency diversity than the conventional scheme since each type of transmission is transmitted over the entire bandwidth of the system instead of a single RF channel. Second, the multiplexing schemes described herein allow the receiving unit 1054 to receive and demodulate all types of transmission with a single RF unit that is tuned to a single RF frequency. This means the design of the wireless device. In contrast, the conventional scheme may require multiple RF units to recover the different types of transmission sent by different RF channels. The techniques described herein for issuing different types of airborne transmission can 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 used to issue different types of transmission can be implemented within one or more specific application integrated circuits (ASICs -application specific integrated circuit), digital signal processors (DSPs) signal processors), digital signal processing devices (DSPDs), programmable logic devices (PLDs), programmable field gate arrays (FPGA), processors, controllers, micro -controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. The processing units in a wireless device used to receive different types of transmission may also be implemented within one or more ASICs, DSPs, and so on. For a software implementation, the techniques described herein may be implemented with modules (e.g., procedures, functions, etc.) that perform the functions described herein. The software codes may be stored in a memory unit (e.g., memory unit 1042 or 1092 in Figure 10) and executed by a processor (e.g., controller 1040 or 1090). The memory unit may be implemented within the processor or external to the processor, in which case it may be communicatively coupled to the processor by various means as is known in the art. The headings are included here for reference and to help locate some sections. These headings are not intended to limit the scope of the concepts described herein, and these concepts may have applicability in other sections throughout the specification. The above description of the described embodiments is provided to enable the person skilled in the art to make or use the present invention. Various modifications to these modalities will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without being insulated from the spirit or scope of the invention. Accordingly, the present invention is not intended to be limited to the embodiments shown herein but should encompass the broadest scope consistent with the principles and novel features described herein.

Claims (66)

1. NOVELTY OF THE INVENTION Having described the invention as antecedent, the content of the following claims is claimed as property: CLAIMS 1. A method for emitting data in a wireless emission network, characterized in that it comprises: multiplexing data for a wide area transmission in a first transmission interval, the wide area transmission being sent from a plurality of transmitters in the network; multiplexing data for a local transmission by a second transmission interval, the local transmission being sent from a subset of the plurality of transmitters; and broadcast broadband and local broadcasts via a wireless link. The method according to claim 1, characterized in that different local transmissions are sent from different subsets of the plurality of transmitters. The method according to claim 1, characterized in that different wide-area transmissions are sent from different pluralities of transmitters. The method according to claim 1, further characterized in that it comprises: multiplexing the data for in-situ transmission over a third transmission interval, sending the transmission in-situ from a smaller subset of the subset of the plurality of transmitters. The method according to claim 1, characterized in that the data for wide area transmission is multiplexed by time division (TDM) with the data for local transmission, and where the first and second transmission intervals are the time segments first and second, respectively, of a frame of a predetermined duration. The method according to claim 1, characterized in that the data for wide area transmission is multiplexed by frequency division (FDM) with the data for local transmission, and where the first and second transmission intervals are the time segments first and second, respectively, of a frame of a predetermined duration. The method according to claim 1, characterized in that the wireless broadcast network uses orthogonal frequency division multiplexing (OFDM). The method according to claim 7, characterized in that the data for wide area transmission is multiplexed by time division (TDM) with the data for local transmission, where the first transmission interval includes all the frequency subbands usable for the transmission of data in a first time segment of a frame, and wherein the second transmission interval includes all the frequency subbands usable for the transmission of data in a second time segment of the frame. The method according to claim 8, characterized in that the data for the local transmission is multiplexed into sub-bands of frequencies smaller than those usable in order to reduce the interference. The method according to claim 9, characterized in that the data for the local transmission from the subset of the plurality of transmitters is multiplexed into subbands of frequencies that are orthogonal to the frequency bands used by at least one other subset of the plurality of transmitters. transmitters. 11. The method according to claim 9, characterized in that the data for the local transmission is multiplexed in pseudo-randomly selected frequency sub-bands of all the usable frequency sub-bands. The method according to claim 1, further characterized in that it comprises: processing the data for wide area transmission according to a first coding and modulation scheme, where the processed data for wide area transmission is multiplexed in the first interval of transmission; and processing the data for local transmission according to a second coding and modulation scheme, where the data processed for local transmission is multiplexed in the second transmission interval. 13. The method according to claim 12, characterized in that the first and second coding and modulation schemes are selected based on the desired coverage for broad and local area transmissions, respectively. The method according to claim 12, characterized in that the second coding and modulation scheme has a lower spectral efficiency than the first coding and modulation scheme to extend the coverage for local transmission. The method according to claim 12, characterized in that the first coding and modulation scheme has a lower spectral efficiency than the second coding and modulation scheme. 16. The method according to claim 1, further characterized in that it comprises: processing the data for broad and local area transmissions based on the transmission in which the data and the type of data are sent. The method according to claim 1, further characterized in that it comprises: multiplexing a first pilot in a third transmission interval, the first pilot being suitable for deriving a first channel calculation for wide area transmission; and multiplexing a second pilot in a fourth transmission interval, the second pilot being suitable for deriving a second channel calculation for local transmission. The method according to claim 17, characterized in that the first and second pilots are each multiplexed into different sets of frequency subbands in different symbol periods. The method according to claim 8, further characterized in that it comprises: multiplexing a first pilot in different sets of frequency sub-bands used for the pilot transmission in different periods of symbols of the first time segment, the first pilot being suitable for deriving a first channel calculation for broad area transmission; and multiplexing a second pilot into different sets of frequency subbands used for transmitting the pilot at different symbol periods of the second time segment, with the second pilot being suitable for deriving a second channel calculation for local transmission. The method according to claim 17, further characterized in that it comprises: generating the second pilot with an orthogonal sequence assigned to the subset of the plurality of transmitters, wherein the second pilot for the subset of the plurality of transmitters is orthogonal to at least one second pilot for at least another subset of the plurality of transmitters. The method according to claim 17, further characterized in that it comprises: generating the second pilot with a pseudo-random sequence assigned to the subset of the plurality of transmitters, wherein the second pilot for the subset of the plurality of transmitters is pseudo-random with with respect to at least one other second pilot for at least one other subset of the plurality of transmitters. The method according to claim 17, further characterized in that it comprises: multiplying the modulation symbols for different frequency subbands with a pseudo-random sequence assigned to the subset of the plurality of transmitters in order to obtain scaled symbols, where the pseudo sequence random is used for each period of symbols; and multiplying the scaled symbols for different periods of symbols with an orthogonal sequence assigned to the subset of the plurality of transmitters in order to generate the second pilot, where the second pilot for the subset of the plurality of transmitters is pseudo-random in frequency and orthogonal in time with respect to at least one other second pilot for at least one other subset of the plurality of transmitters. The method according to claim 1, further characterized in that it comprises: multiplexing complementary information for wide area transmission in a third transmission interval; and multiplexing complementary information for local transmission in a fourth transmission interval. The method according to claim 23, characterized in that the complementary information for wide area transmission indicates the location of frequency and time of each data channel for wide area transmission, and where the complementary information for local transmission indicates the location of frequency and location of each data channel for local transmission. The method according to claim 1, further characterized in that it comprises: selecting the first and second transmission intervals based on a quantity of data to emit the wide area transmission and a quantity of data to be transmitted for the local transmission. 26. The method according to claim 1, further characterized in that it comprises: adjusting the first and second transmission intervals based on the time of day. 27. The method according to claim 1, further characterized in that it comprises: adjusting the first and second transmission intervals based on a predetermined program. 28. An apparatus in a wireless transmission network, characterized in that it comprises: a multiplexer operable to receive and multiplex the data for a wide area transmission in a first transmission interval and to receive and multiplex the data for a local transmission in a second transmission interval, the wide area transmission being sent from a plurality of transmitters in the network, and the local transmission being sent from a subset of the plurality of transmitters; and an operable transmitting unit for broadcasting local and wide-area transmissions via a wireless link. 29. The apparatus according to claim 28, characterized in that the wireless broadcast network uses orthogonal frequency division multiplexing (OFDM), where the data for wide area transmission is multiplexed by time division. (TDM) with the data for the local transmission, where the first transmission interval includes all the subbands of frequencies usable for the transmission of data in a first time segment of a frame, and where the second transmission interval includes all the sub-bands of usable frequencies for the transmission of data in a second time segment of the frame. 30. The apparatus according to claim 28, further characterized in that it comprises: a first data processor operable to process the data for wide area transmission according to a first coding and modulation scheme; and a second data processor operable to process the data for local transmission according to a second coding and modulation scheme; and where the multiplexer is operable to multiplex the processed data for wide area transmission in the first transmission interval and to multiplex the processed data for local transmission in the second transmission interval. 31. The apparatus according to claim 30, characterized in that the first data processor is further operable to generate a first suitable pilot for deriving a first channel calculation for wide area transmission, where the second data processor is further operable to generate a second pilot suitable for deriving a second channel calculation for local transmission, and where the multiplexer is further operable to multiplex the first pilot in a third transmission interval and to multiplex the second pilot in a fourth transmission interval. 32. The apparatus according to claim 28, characterized in that the multiplexer is further operable to multiplex complementary information for wide area transmission in a third transmission interval and to multiplex the complementary information for local transmission in a fourth transmission interval. The apparatus according to claim 28, further characterized in that it comprises: an operable controller for selecting the first and second transmission intervals based on a quantity of data to be transmitted for broad area transmission and a quantity of data to be issued for the local transmission. 34. An apparatus in a wireless broadcast network, characterized in that it comprises: means for multiplexing the data for a wide area transmission in a first transmission interval, the wide area transmission being sent from a plurality of transmitters in the network; means for multiplexing the data for a local transmission in a second transmission interval, the local transmission being sent from a subset of the plurality of transmitters; and means for broadcasting the multiplexed data for local and wide area transmissions via a link. 35. The apparatus according to claim 34, characterized in that the wireless emission network uses orthogonal frequency division multiplexing (OFDM), where the data for wide area transmission is multiplexed by time division. (TDM) with the data for the local transmission, where the first transmission interval includes all the frequency subbands usable for the transmission of data in a first time segment of a frame, and where the second transmission interval includes all the sub-bands of usable frequency for the transmission of data in a second time segment of the frame. 36. The apparatus according to claim 34, further characterized in that it comprises: means for processing the data for wide-area transmission according to a first coding and modulation scheme, wherein the processed data for broad-area transmission is multiplexed in the first transmission interval; and means for processing the data for local transmission according to a second coding and modulation scheme, where the data processed for local transmission is multiplexed in the second transmission interval. 37. The apparatus according to claim 34, further characterized in that it comprises: means for multiplexing a first pilot in a third transmission interval, the first pilot being suitable for deriving a first channel calculation for wide area transmission; and means for multiplexing a second pilot in a fourth transmission interval, the second pilot being suitable for deriving a second channel calculation for channel transmission. 38. The apparatus according to claim 34, further characterized in that it comprises: means for multiplexing complementary information for wide area transmission in a third transmission interval; and means for multiplexing complementary information for local transmission in a fourth transmission interval. 39. The apparatus according to claim 34, further characterized in that it comprises: means for selecting the first and second transmission intervals based on a quantity of data to be issued for broad area transmission and a quantity of data to be issued for local transmission . 40. A method for receiving data in a wireless broadcast network, characterized in that it comprises: receiving via a wireless link an emission transmission comprised of a broad area transmission and a local transmission, the wide area transmission being sent from a plurality of transmitters in the network, and sending the local transmission from a subset of the plurality of transmitters; if wide area transmission is being received, demultiplex the data for wide area transmission from a first transmission interval; and if local transmission is being received, demultiplexing the data for local transmission from a second transmission interval 41. The method according to claim 40, characterized in that the data for broad-area transmission is multiplexed by frequency division (FDM). ) with the data for local transmission, and where the first and second transmission intervals are first and second sets of frequency subbands, respectively, obtained with the modulation of the multi-carrier. 42. The method according to claim 40, characterized in that the data for wide area transmission is multiplexed by time division (TDM) with the data for local transmission, and where the first and second transmission intervals are the time segments first and second, respectively, of a plot. 43. The method according to claim 42, characterized in that the first time segment for wide area transmission is before the second time segment for local transmission. 44. The method according to claim 40, characterized in that the wireless broadcast network uses orthogonal frequency division multiplexing (OFDM). 45. The method according to claim 44, characterized in that the data for broad area transmission is multiplexed by time division (TDM) with the data for local transmission, wherein the first transmission interval includes all the frequency subbands usable for the transmission of data in a first time segment of a frame, and wherein the second transmission interval includes all the frequency subbands usable for data transmission in a second segment of time of the plot. 46. The method according to claim 40, further characterized by comprising: if the wide area transmission is being received, processing the data for wide area transmission according to a first demodulation and decoding scheme; and if local transmission is being received, process the data for local transmission according to a second demodulation and decoding scheme. 47. The method according to claim 40, further characterized in that it comprises: if the wide area transmission is being received, demultiplexing the complementary information for the wide area transmission coming from a third transmission interval; and if local transmission is being received, demultiplex additional information for local transmission from a fourth transmission interval. 48. The method according to claim 47, characterized in that the complementary information for wide area transmission indicates the location of frequency and time of each data channel for broad area transmission, and where the complementary information for local transmission indicates the location of frequency and time of each data channel for local transmission. 49. The method according to claim 40, further characterized in that it comprises: if wide area transmission is being received, demultiplexing a first pilot from a third transmission interval, deriving a first channel calculation for wide area transmission with base in the first pilot, and process the data for broad area transmission with the first channel calculation. 50. The method according to claim 49, further characterized in that it comprises: if the local transmission is being received, demultiplexing a second pilot from a fourth transmission interval, deriving a second channel calculation for the local transmission based on the second pilot, and process the data for local transmission with the second channel calculation. 51. The method according to claim 50, characterized in that the first and second channel calculations are respectively associated with the first and second impulse response calculations having different durations. 52. The method according to claim 51, further characterized in that it comprises: adjusting the thresholds to obtain a zero output of the channel derivations of the first impulse response calculation that lie below a first predetermined threshold; and executing the thresholds to obtain a zero output of the channel derivations of the second impulse response calculation that lie below a second predetermined threshold. 53. The method according to claim 52, characterized in that the first predetermined threshold is equal to the second predetermined threshold. 54. The method according to claim 50, further characterized in that it comprises: if the wide area transmission is being received, process the first pilot with a first set of at least one time domain filter to derive the first channel calculation; and if local transmission is being received, process the second pilot with a second set of at least one filter in the time domain to derive the second channel calculation. 55. The method according to claim 54, characterized in that the first and second sets of at least one filter in the time domain have different durations, different coefficients, or both different durations and different coefficients. 56. A wireless device in a wireless transmission network, characterized in that it comprises: a receiving unit operable to receive via a wireless link an emission transmission comprised of a broad area transmission and a local transmission, the wide area transmission being sent from a plurality of transmitters in the network, and sending the local transmission from a subset of the plurality of transmitters; and a demultiplexer, operable to demultiplex data for wide area transmission from a first transmission interval if wide area transmission is being received and to demultiplex data for local transmission from a second transmission interval if it is being received the local transmission. 57. The apparatus according to claim 56, characterized in that the wireless broadcast network uses orthogonal frequency division multiplexing (OFDM), where the data for wide area transmission is multiplexed by time division. (TDM) with the data for the local transmission, where the first transmission interval includes all the subbands of frequencies usable for the transmission of data in a first time segment of a frame, and where the second transmission interval includes all the sub-bands of usable frequency for the transmission of data in a second time segment of the frame. 58. The apparatus according to claim 56, further characterized in that it comprises: a data processor operable to process the data for wide area transmission according to a first demodulation and decoding scheme if the wide area transmission is being received and processing the data for local transmission according to a second demodulation and decoding scheme if local transmission is being received. 59. The apparatus according to claim 56, characterized in that the demultiplexer is further operable to demultiplex complementary information for broad area transmission originating from a third transmission interval if the wide area transmission is being received and to demultiplex the complementary information for the transmission. local transmission from a fourth transmission interval if local transmission is being received. 60. The apparatus according to claim 56, further characterized in that it comprises: an operable channel calculator for deriving a first channel calculation for wide area transmission based on a first demultiplexed pilot from a third transmission interval if the wide area transmission is being received and for derive a second channel calculation for local transmission based on a second demultiplexed pilot from a fourth transmission interval if local transmission is being received; and an operable demodulator for processing the data for wide area transmission with the first channel calculation if the wide area transmission is being received and for processing the data for local transmission with the second channel calculation if the transmission is being received local. 61. The apparatus according to claim 56, characterized in that the receiving unit is operable to receive both wide area transmission and local transmission by concurrently tuning to a single radio frequency. 62. A wireless apparatus in a wireless communication network, characterized in that it comprises: means for receiving via a wireless link an emission transmission comprised of a wide area transmission and a local transmission, the wide area transmission being sent from a plurality of transmitters in the network, and sending the local transmission from a subset of the plurality of transmitters; means for demultiplexing data for wide area transmission from a first transmission interval if wide area transmission is being received; and means for demultiplexing the data for local transmission from a second transmission interval if local transmission is being received. 63. The apparatus according to claim 62, characterized in that the wireless emission network uses orthogonal frequency division multiplexing (OFDM), characterized in that the data for wide area transmission is multiplexed by time division (TDM) with the data for the local transmission, where the first transmission interval includes all the frequency subbands usable for the transmission of data in a first time segment of a frame, and where the second transmission interval includes all the frequency subbands usable for the transmission of data in a second time segment of the frame. 64. The apparatus according to claim 62, further characterized in that it comprises: means for processing the data for wide area transmission according to a prior demodulation and decoding scheme if the wide area transmission is being received; and means for processing the data for local transmission according to a second demodulation and decoding scheme if the local transmission is being received. 65. The apparatus according to claim 62, further characterized in that it comprises: means for demultiplexing complementary information for broad area transmission from a third transmission interval if wide area transmission is being received; and means for demultiplexing complementary information for local transmission from a fourth transmission interval if local transmission is being received. 66. The apparatus according to claim 62, further characterized in that it comprises: means for demultiplexing a first pilot from a third transmission interval if the wide area transmission is being received; means for demultiplexing a second pilot from a fourth transmission interval if the local transmission is being received; means for deriving a first channel calculation for broad area transmission based on the first pilot if wide area transmission is being received; means for deriving a second channel calculation for broad area transmission based on the first pilot if the local transmission is being received; means for processing the data for wide area transmission with the first channel calculation if broad area transmission is being received; and means for processing the data for local transmission with the second channel calculation if the local transmission is being received.