MXPA06004518A - Frequency division multiplexing of multiple data streams in a wireless multi-carrier communication system - Google Patents

Abstract

Techniques for multiplexing multiple data streams using frequency division multiplexing (FDM) in an OFDM system are described. M disjoint"interlaces"are formed with U usable subbands. Each interlace is a different set of S subbands, where . The subbands for each interlace are interlaced with the subbands for each of the other interlaces. M slots may be defined for each symbol period and assigned slot indices 1 through M. The slot indices may be mapped to interlaces such that (1) frequency diversity is achieved for each slot index and (2) the interlaces used for pilot transmission have varying distances to the interlaces used for each slot index, which improves channel estimation performance. Each data stream may be processed as data packets of a fixed size, and different numbers of slots may be used for each data packet depending on the coding and modulation scheme used for the data packet.

Description

"MULTIPLEXION BY MULTIPLE FREQUENCY DIVISION FLOWS OF DATA IN A COMMUNICATIONS SYSTEM WIRELESS MULTIPLE CARRIER " FIELD OF THE INVENTION The present invention relates in general terms to communications, and more specifically to techniques for multiplexing multiple data streams in a multiple carrier wireless communications system.

BACKGROUND OF THE INVENTION A multiple carrier communication system uses multiple carriers for the transmission of data. These multiple carriers can be provided by orthogonal frequency division multiplexing (OFDM), some other multiple carrier modulation techniques, or some other construction. The OFDM effectively divides the general bandwidth of the system into multiple (N) orthogonal frequency subbands. These sub-bands are also referred to as tones, carriers, subcarriers, groups, and frequency channels. With the OFDM, each subband is associated with a subcarrier respective that can be modulated with the data. A base station in a multi-carrier communication system can simultaneously transmit multiple data streams. Each data stream can be processed (e.g., encoded and modulated) separately in the base station and consequently can be recovered (e.g., remodulated and decoded) independently by a wireless device. The multiple data streams can be fixed or variable data rates and can use the same or different coding and modulation schemes. Multiplexing multiple data streams for simultaneous transmission can be challenging if these flows are of a variable nature (for example, they have data rates and / or coding and modulation schemes that change over time). In a simple multiplexing scheme, the multiple data streams are assigned different time intervals or symbol periods that use multiplexing by time division (TDM - time division multiplexing). For this TDM scheme, only one data stream is sent at any given time, and this data stream uses all available sub-bands for data transmission.

This TDM scheme has some undesirable characteristics. First, the amount of data that can be sent in the smallest time unit assignable to a given data flow, which can be visualized as the "granularity" for the data flow, is dependent on the coding and modulation scheme used for the data flow. data flow. Then, different coding and modulation schemes with different granularities can be associated, which can complicate the allocation of resources to the data flows and can result in an inefficient use of resources. Secondly, if the granularity for a particular coding and modulation scheme is too large with respect to the decoding capability of a wireless device, then a large temporary input memory may be required in the wireless device in order to store the received symbols . Therefore, there is a need in the art for techniques for effectively multiplexing multiple data streams in a multiple carrier communication system.

BRIEF DESCRIPTION OF THE INVENTION This describes techniques for multiplexing multiple data streams using frequency division multiplexing (FDM frequency division multiplexing) into a multiple carrier wireless communications system (eg, OFDM). In one embodiment, M "interlaced" disjointed or non-superimposed with U sub-bands usable for transmission are formed, where M > 1 and U > 1. The interlaced do not overlap because each usable subband is included only in an interlaced one. Each interlacing is a different set of S subbands, where ü = M «S. The S subbands in each interlacing can be selected from S 'subbands that are evenly distributed across the N total subbands and evenly spaced by M subbands, where N = M «S' and S '= S. This interlaced subband structure can provide frequency diversity and simplify processing in a receiver. For example, the receiver can execute a fast Fourier transform (FFT - fast Fourier transform) "partial" of S 'points for each interlacing of interest, instead of a total FFT of N points. The interlaced Ms can be used to transmit the multiple data streams in an FDM manner. In one mode, each interleaving is used only by one data stream in each symbol period, and can send to M data flows in the M interleaved in each symbol period. In one modality, the multiple data streams are assigned "intervals", where each interval is a transmission unit that can be equal to an interleaving in a symbol period. M intervals are then made available in each symbol period and the indexes of interval 1 to M can be assigned. Each interval index can be interleaved in each period of symbols based on an interlaced interval mapping scheme. One or more interval indices can be used for an FDM pilot, and the remaining interval indices can be used for data transmission. Interleaving interval mapping may be such that the interleaves used for pilot transmission have varying distances to the interleaves used for each interval index in different periods of OFDM symbols. This allows all interval indices used for data transmission to achieve similar channel calculation performance. Each data flow can be processed as data packets of a fixed size. In this case, different numbers of intervals can be used to each data packet depending on the coding and modulation scheme used for the data packet. Alternatively, each data stream can be processed as data packets of varying sizes. For example, packet sizes may be selected such that a whole number of data packets are sent in each interval. In any case, if multiple data packets are sent in a certain interval, then the data symbols for each data packet can be distributed in all the subbands used for the interval, so that the frequency diversity for each packet is reached. data sent in the interval. In the following, various aspects and embodiments of the invention are described in detail.

BRIEF DESCRIPTION OF THE DRAWINGS The features and nature of the present invention will become more apparent from the following detailed description set forth below when taken in conjunction with the drawings in which like reference characters are identified corresponding throughout the drawings. the same and where: Figure 1 shows a block diagram of a base station and a wireless device; Figure 2 shows a super-tra structure as an example; Figure 3 shows an interlaced subband structure; Figures 4A and 4B show the "stepped" and "recycled" FDM pilots, respectively; Figure 5 shows an example mapping of interleaved interval indices; Figure 6 illustrates the coding of a data block with an external code; Figures 7A and 7B show the transmission of packets for different nodes; Figures 8A and 8B show the division of different numbers of packages into intervals; Figure 9A shows a block diagram of a transmission data processor (TX); Figure 9B shows a block diagram of a modulator; Figure 10A shows a block diagram of a demodulator; and Figure 10B shows a block diagram of a reception data processor (RX).

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 mode or design described herein as "by way of example" is not necessarily to be construed as being preferred or advantageous over other embodiments or designs. The multiplexing techniques described herein can be used for various wireless multiple-carrier communication systems. These techniques can also be used for the downlink as well as the uplink. The downlink (or forward link) refers to the communications link from the base stations to the wireless devices, and the uplink (or reverse link) refers to the communication link from the wireless devices to the base stations. For clarity, these techniques for the downlink in an OFDM-based system are described below. Figure 1 shows a block diagram of a base station 110 and a wireless device 150 in a wireless system 100 using OFDM. The base station 110 is generally a fixed station and it can also be referred to as a base transceiver system (BTS), an access point, a transmitter; or some other terminology. The wireless device 150 can be fixed or mobile and can also be referred to as a user terminal, mobile station, receiver, or some other terminology. The wireless device 150 can also be a portable unit such as a cell phone, a handheld device, a wireless module, a personal digital assistant (PDA), etc. In the base station 110, a TX data processor 120 receives multiple (T) data streams (or "traffic" data) and processes (e.g., encodes, distributes, and maps symbols) each data stream to generate symbols of data. As used herein, a "data symbol" is a modulation symbol for the pilot (which are data known a priori by both the base station and wireless devices), and a modulation symbol is a complex value for a point in a constellation of signals for a modulation scheme (for example, M-PSK, M-QAM, etc.). The TX data processor 120 also multiplexes the data symbols for the T data streams and data symbols in the subbands appropriate and provides a flow of compound symbols. A modulator 130 performs the modulation of OFDM in the multiplexed symbols in the stream of compound symbols in order to generate the OFDM symbols. A transmitter unit (TMTR) 132 converts the OFDM symbols into analog signals and additionally conditions (eg, amplifies, filters, and overconverts in frequency) the analog signals to generate a modulated signal. The base station 110 then transmits the modulated signal from an antenna 134 to the wireless devices in the system. In the wireless device 150, the signal transmitted from the base station 110 is received by an antenna 152 and is provided to a receiving unit (RCVR) 154. The receiving unit 154 conditions (eg, filters, amplifies, and subverts in frequency ) the received signal and digitizes the conditioned signal to generate a flow of input samples. A demodulator 160 performs the demodulation of OFDM in the input samples to obtain the received symbols for one or more data streams of interest, and also performs detection (eg, equalization or matching filtering) on the received symbols to obtain the symbols of detected data, which are calculations of the data symbols sent by the base station 110. An RX data processor 170 then processes (e.g., unmasks, groups, and decodes the symbols) the detected data symbols for each selected data stream and provides decoded data for that stream . The processing by the demodulator 160 and the data processor RX 170 is complementary to the processing by the modulator 130 and the TX data processor 120, respectively, in the base station 110. The controllers 140 and 180 direct the operation in the base station 110 and the wireless device 150, respectively. Memory units 142 and 182 provide storage for program and data codes used by controllers 140 and 180, respectively. The controller 140 or a scheduler 144 may allocate system resources for the T data streams. The base station 110 may transmit the T data streams for various services such as broadcast, multi-broadcast, and / or unicast services. An emission transmission is sent to all wireless devices within a designated coverage area, a multi-broadcast transmission is sent to a group of wireless devices, and A transmission of uniemissions is sent to a specific wireless device. For example, the base station 110 can output a number of data streams for multimedia programs (e.g., television) and for multimedia content such as video, audio, teletext, data, audio / video clips, etc. A single multimedia program can be broadcast as three separate data streams for video, audio, and data. This allows independent reception of portions of video, audio, and multimedia program data by a wireless device. Figure 2 shows an exemplary superframe structure 200 that can be used for the system 100. The T data streams can be transmitted in superframes, each superframe having a predetermined duration. A super-frame can also be referred to as a frame, time slot, or some other terminology. For the embodiment shown in Figure 2, each superframe includes a field 212 for one or more TDM pilots, a field 214 for control data / supplementary information, and a field 216 for traffic data. The TDM pilot (s) can be used by a wireless device for synchronization (eg, frame detection, frequency error calculation, acquisition of synchronization, etc.). 'Control data / supplementary information may indicate various parameters for the T data streams (for example, the coding and modulation scheme used for each data flow, the specific location of each data stream within the super-frame, etc) . The T data streams are sent in field 216. Although not shown in Figure 2, each superframe can be divided into multiple frames of the same size (e.g., four) in order to facilitate data transmission. Other frame structures for the system 100 may also be used. Figure 3 shows an interlaced subband structure 300 that can be used for the system 100. The system 100 uses an OFDM structure having N total subbands. Sub-bands can be used for data and pilot transmission and are called "usable" subbands, where U = N. The remaining G sub-bands are not used and are called "guard" subbands, where N = U + G. As an example, the system 100 can use an OFDM structure with N = 4096 total subbands, U = 4000 usable subbands, and G = 96 guard subbands. The U usable subbands can set to M interleaved or set of separate subbands. The interlaced Ms are separated or not overlapped because each of the U usable subbands belongs only to an interlaced one. Each interleaving contains S usable subbands, where U = M-S. Each interleaving can be associated with a different group of S '= N / M subbands that are evenly distributed in the N total subbands such that the consecutive subbands in the group are spaced by M subbands. For example, group 1 can contain subbands 1, M + l, 2M + 1, etc., group 2 can contain subbands 2, M + 2, 2M + 2, and so on, and group M can contain subbands M , 2M, 3M, etcetera. For each group, S of the S 'subbands are usable subbands and the remaining S'-S subbands are guard subbands. Each interleaving can then contain the S subbands that can be used in the group associated with the interleaving. For the structure of OFDM as an example described above, M = 8 interlaced can be formed, each interleaving containing S = 500 usable subbands selected from among S '= 512 subbands that are uniformly spaced by M = 8 subbands. Consequently, the S subbands usable in each interlacing are intertwined with the S sub-bands usable in each of the other interlaced M-l. In general, the system can use any OFDM structure with any number of total, usable, and guard subbands. Any number of interlaces can also be formed. Each interleaving can contain any number of usable subbands and any number of U usable subbands. The interlaces can also contain the same number or a different number of usable subbands. For simplicity, the following description is for the interlaced subband structure shown in Figure 3 with M interleaved and each interleaved contains S uniformly distributed usable subbands. This interlaced subband structure provides several advantages. First, frequency diversity is achieved since each interleaving contains usable subbands taken from the entire bandwidth of the system. Secondly, a wireless device can retrieve the data / pilot symbols in a given interleaving by performing an FFT of S 'points instead of a total FFT of N points, which can simplify processing by the wireless device.

The base station 110 may transmit an FDM pilot in one or more interleaves to allow the wireless devices to perform various functions such as, for example, channel calculation, frequency tracking, time tracking, etc. The base station 110 can transmit the FDM pilot and the traffic data in various ways. Figure 4A shows a schema 400 of data transmission and pilot with a "stepped" FDM pilot. In this example, M = 8, an interleaving is used for the FDM pilot in each symbol period, and the remaining seven interleaves are used for traffic data. The FDM pilot is sent by two alternately designated interleavers so that the pilot symbols are sent in an interlace (e.g., interleaved 3) in periods of odd number symbols and in another interlace (e.g. interlaced 7) in periods of even-numbered symbols. The two interlaced ones used for the FDM pilot are staggered or displaced by M / 2 = 4 interlaced. This stepping allows wireless devices to observe the channel response for more subbands, which can improve performance. Figure 4B shows a scheme 410 of data and pilot transmission with a "recycled" FDM pilot. In this example, M = 8, an interleaving is used for the FDM pilot in each symbol period, and the remaining seven interleavers are used for traffic data. The FDM pilot is sent in the interleaved eights in a cyclic manner so that the pilot symbols are sent in a different interleaving in each period duration of M symbols. For example, the FDM pilot may be sent in interleaving 1 in symbol period 1, then interleaving 5 in symbol period 2, then interlacing 2 in symbol period 3, etc., then interlacing 8 in the period 8 of symbols, after return to interlaced 1 in period 9 of symbols, and so on. This recycling allows wireless devices to observe the channel response for all sub-bands. In general, an FDM pilot can be sent in any number of interleavers and in any of the interlaced Ms in each symbol period. The FDM pilot can also be sent using any pattern, two of which are shown in Figures 4A and 4B. The base station 110 may transmit T data flows in the M interleaved of various ways In a first mode, each data flow is sent in the same or more interleaved in each symbol period in which the data flow is sent. For this modality, the interlaces are assigned statistically to each data flow. In a second embodiment, each data stream may be sent by different interleaves at different symbol periods in which the data flow is sent. For this modality, the interleavers are assigned dynamically to each data flow, which can improve the frequency diversity and also ensure that the quality of the channel calculation is independent of the index or interval indices assigned to the data flow. The second mode can be viewed as a frequency hopping form and is described in more detail below. To average the channel calculation and the detection performance for all T data flows, the transmission scheme 410 can be used for the first modality with statically assigned interlaces, and can be used either transmission scheme 400 or 410 for the second mode with interlaces dynamically assigned. If the FDM pilot is sent by the same interleaver (which is called pilot interleaving) in each period of and is used to obtain channel calculations for the interlaced Ms, then the channel calculation for an interlace that is closer to the pilot interleaving is typically better than the channel calculation for an interlace that is farther from the pilot interleaving . The detection performance for a data stream may be degraded if the interleaved flow that is removed from the pilot interleaving is consistently assigned to the flow. The assignment of interleaves with variable distances (or spacing or offset) to the pilot interleaving can prevent this degradation of performance due to a compensation of the channel calculation. For the second mode, M intervals can be defined for each symbol period, and each interval can be mapped to an interleaving in a symbol period. A usable interval for the traffic data is also called a data range, and a usable range for the FDM pilot is also called the pilot interval. The M intervals in each symbol period can be the indices determined 1 through M. The interval index 1 can be used for the FDM pilot, and the pilot indexes 2 through M can be used for data transmission. The T data streams can be assigned intervals with indexes 2 through M in each symbol period. The use of intervals with fixed indexes can simplify the assignment of intervals to data flows. The M interval indices can be mapped to the interlaced Ms in each symbol period based on any mapping scheme that can achieve the desired frequency diversity and channel calculation performance. In a first interlocking interval mapping scheme, the interval indices are mapped in the interleaved in a permuted way. For transmission scheme 400 with M = 8 and a pilot interval and seven data intervals in each symbol period, mapping can be performed as explained below. The eight interlaced ones can be denoted by an original sequence. { Ii, I2, I3, I4, I5, I ?, I7, le). A permuted sequence can be formed as. { Ii, I5, I3, I, I2, Ißr li r le} • The i-th interleaved in the original sequence is placed in the £, rth position in the permuted sequence, where i e. { 1 ... 8 } , ibr e. { 1 ... 8 } , and (ijbr-l) is an inverse bit index of (i-1). A compensation of -1 for i and ibr is used because these indexes start from 1 instead of 0. As an example, for i = 7, (i-1) = 6, the bit representation is? 110 ', the index of bit inverse is? 011 ', (ibr-l) = 3, and ir = 4. Consequently, the 7th interleaved in the original sequence is placed in the 4th position in the permuted sequence. The two interleaves used for the FDM pilot are then combined in the permuted sequence to form an interlaced trimmed sequence. { Il r I5, I3 /, I2, le, I4 # - le} • The Jc-th interval index used for data transmission- (or the Jc-th data interval index), for f e. { 2 ... 8} f is then mapped to the (-1) -th interleaved in the interlaced trim sequence. After that, for each symbol period, the trimmed interlaced sequence is shifted to the right two positions circularly and rolled to the left. The Jc-th data interval index is mapped back to the (Jc-l) -th interlace in the circularly shifted interlace clipped sequence. Figure 5 shows the mapping of the interval indices in the interlaces for the first mapping scheme described above. Mapping index 1, which is used for the FDM pilot, is mapped to interleaved 3 and 7 in periods of alternate symbols for transmission scheme 400. The data interval indices 2 to 8 are mapped in the seven intertwined in the interlaced trimmed sequence. { Ii, I5, I3 /, I2, Ie, I4, Is) for the first period of symbols, to the cut sequence of interlaced displaced circularly or cyclically. { I4, I8, Il? I5, l3 /, I2, Id) for the second period of symbols, and so on. As shown in Figure 5, each data interval index is mapped into seven different interleaves in seven consecutive symbol periods, where one of the seven interleaved is either the 3 or the 7 interleaved. The seven data interval indexes reach after a similar performance. In a second interlaced interval mapping scheme, the interval indices are mapped into entanglements in a pseudo-random manner. A pseudo-random number generator (PN-pseudo-random) can be used to generate PN numbers that are used to map interleaved interval indices. The PN generator can be implemented with a linear feedback shift register (LFSR) that implements a particular generator polynomial, for example, g (x) = x15 + x14 + 1- For each symbol period jr the LFSR is updated and the least significant V bits (LSBs - least significant bits) in the LSFR can be denoted as PN (j), where j = 1, 2, ... and V = log2 M. The Jc-th data interval index, for k e. { 2 ... M} , can be mapped in the interlace [(PN (j) + Jc) mod M] + l, if this interleaving is not used for the FDM pilot, and in the interleaving [PN (j) + Jc + 1], of another way . In a third intertwining interval mapping scheme, the interval indices are mapped in a circular fashion. For each symbol period j, the Jc-th data interval index, for k e. { 2 ... M} , it can be mapped in the interlaced [(j + Jc) mod M] + l, if this interleaving is not used for the FDM pilot, and in the interlaced [(j + k + 1) mod M] + l, in another way. Consequently, the M interval indices can be mapped into the M intertwined in various ways. Some interleaving interval mapping schemes by way of example have been described above. Other mapping schemes may also be used, and this is within the scope of the invention. The intervals can be assigned to the T data flows in various ways. In a first interval allocation scheme, each data flow is assigned a sufficient number of intervals in each super-frame to transmit a non-negative integer number of data packets (that is, zero or more data packets). For this scheme, the data packets can be defined as having a fixed size (i.e., a predetermined number of information bits), which can simplify coding and decoding for data packets. Each fixed-size data packet can be encoded and modulated to generate a coded packet having a variable size that is dependent on the coding and modulation scheme for the packet. Then, the number of intervals necessary to transmit the encoded packet is dependent on the coding and modulation scheme used for the packet. In a second interval allocation scheme, each data stream may be assigned a non-negative integer number of intervals in each super-frame, and a whole number of data packets may be sent in each allocated interval. The same coding and modulation scheme can be used for all data packets sent at any given interval. Each data packet can have a size that is dependent on (1) the number of data packets that are sent in the interval and (2) the coding and modulation scheme used for that interval. For this scheme, the data packets can have variable sizes. The intervals can also be assigned to the data flows in other ways. For clarity, the following description assumes that the first interval allocation scheme is used by the system. Each data flow can be encoded in various ways. In one embodiment, each data stream is encoded with a concatenated code comprised of an outer code and an inner code. The outer code can be a block code such as a Reed-Solomon (RS) code or some other code. - The internal code can be a Turbo code, a convolutional code, or some other code. Figure 6 shows an external coding scheme by way of example, which uses an external Reed-Solomon code. A data flow is divided into data packets. In one embodiment, each data packet has a fixed size and contains a predetermined number of information bits or L information bytes (e.g., 1000 bits or 125 bytes). The data packets for the data flow are written in the rows of one memory, one packet per row. After Krs data packets have been written in Krs rows, the block coding is Performs column by column, one column at a time. In one mode, each column contains Krs bytes (one byte per row) and is encoded with a Reed-Solomon code (Nrs, Krs) to generate a corresponding keyword that contains Nrs bytes. The first Krs bytes of the keyword are the bytes of data (which are also called systematic bytes) and the last Nrs-Krs bytes are parity bytes (which can be used by a wireless device for error connection). The Reed-Solomon coding generates Nrs-Krs parity bytes for each keyword, which are written in the rows Nrs_Krs to Nr? of memory after the Krs parity rows. A block of RS contains Krs data rows and Nrs - Krs parity rows. In a modality, Nrs = 16 and Krs is a configurable parameter, for example, Krs e. { 12, 14, 16.}. . The Reed-Solomon code is disabled when Krs = Nrs. Each data packet / parity (or each row) of the RS block is then encoded by the internal Turbo code to generate a corresponding encoded packet. A block of code contains Ns coded packets for the Nrs rows of the RS block. The Ns packets encoded for each block of code can be sent in various ways. By For example, each block of code can be transmitted in a super-frame. Each super-frame can be divided into multiple frames (for example, four). Each block of code can then be divided into multiple sub-blocks (for example, four), and each sub-block of the code block can be sent in one frame of the super-frame. The transmission of each block of code in multiple parts through a super-frame can provide diversity of time. Each data stream can be transmitted with or without hierarchical coding, where the term "coding" in this context refers to channel coding instead of data encoding in a transmitter. A data flow can be comprised of two subflows, which are called base flow and improvement flow. The base flow can carry base information and can be sent to all wireless devices within the coverage area of the base station. The improvement stream can carry additional information and can be sent to wireless devices that observe the best channel conditions. With the hierarchical coding, the base flow is coded and modulated to generate a first flow of modulation symbols, and the improvement flow is coded and modulated to generate a second flow of modulation symbols. The same or different coding and modulation schemes can be used for the base flow and the improvement flow. After, the two modulation symbol streams can be scaled and combined to obtain a stream of data symbols. Table 1 shows an example set of eight "modes" that can be suted by the system 100. These eight modes are indexes determined from 1 to 8. Each mode is associated with a specific modulation scheme (for example, QPSK or 16-QAM) and a specific internal code rate (for example, 1/3, 1/2, or 2/3). The first five modes are for "regular" coding with only the base flow, and the last three modes are for hierarchical coding with the base and improvement flows. For simplicity, the same modulation scheme and the internal code rate are used for both base and improvement flows for each hierarchical coding mode.

Table 1 The fourth column of Table 1 indicates the number of intervals needed to transmit a fixed-size data packet for each mode. The Table 1 assumes a data packet size of 2 * S information bits and S subbands usable per interval (for example, S = 500). Each interval has a capacity of S data symbols since the interval is mapped into an interlace with S usable subbands and each subband can carry a data symbol. For mode 1, a data packet with 2 »S bits of information is encoded with an internal 1/3 rate code to generate 6 * S bits of code, which they are mapped later on 3 »S data symbols using QPSK. The 3 * S data symbols for the data packet can be sent in three intervals, each interval carrying S data symbols. Similar processing can be executed for each of the other modes in Table 1. Table 1 shows a design by way of example. Data packets of other sizes can also be used (for example, 500 bits of information, 2000 bits of information, etc.). For example, a packet size of 1000 bits of information may be used for modes 1, 2, and 4, and a packet size of 1333 bits of information may be used for modes 3 and 5. In general, the system may also support any number of modes for any number of coding and modulation schemes, any number of data packet sizes, and any packet size. Figure 7A shows the transmission of a minimum integer number of data packets, using a range in each integer number of symbol periods, for each of the first five modes listed in Table 1. A data packet can be sent using a interval in (1) three periods of symbols for mode 1, (2) two periods of symbols for mode 2, and (3) a period of symbols for the mode. Two data packets can be sent using an interval in three symbol periods for mode 3, since it takes 1.5 intervals for each data packet to be sent. Four data packets can be sent using an interval in three symbol periods for mode 5, since each data packet takes 0.75 intervals to be sent. Figure 7B shows the transmission of a minimum integer number of data packets, using an integer number of intervals in a symbol period, for each of the first five modes listed in Table 1. A packet of data can be sent in a symbol period using (1) three intervals for mode 1, (2) two intervals for mode 2, and (3) a range for mode 4. Two data packets can be sent in a symbol period using three intervals for mode 3. Four data packets can be sent in a symbol period using three intervals for mode 5. As shown in Figures 7A and 7B, the minimum number of data packets can be transmitted in different ways for each mode (except for mode 4). Transmit the minimum number of packages data in a shorter period of time reduces the amount of ON time required to receive the data packets but provides less time diversity. The inverse is true to transmit the minimum number of data packets over a longer period of time. Figure 8A shows the division of a single packet coded into three intervals for mode 1. The three intervals can be for three different interleaved in a symbol period or an interleaved in three different symbol periods. The three intervals can observe different channel conditions. The bits in the encoded packet can be distributed (ie, registered) before the division into three intervals. The distribution for each encoded packet can randomize the signal-to-noise ratio (SNRs) of the bits in the encoded packet, which can improve decoding performance. The distribution can be executed in various ways, as is known in the art. The distribution can also be such that the adjacent bits in the encoded packet are not sent in the same data symbol. Figure 8B shows the division of four coded packets into three intervals for mode 5.

The three intervals can be filled sequentially by the four coded packets, as shown in Figure 8B. When multiple encoded packets share a range (such as for modes 3 and 5), all the bits to be sent in the range can be distributed in such a way that the bits for each encoded packet sent in the interval are distributed in the sub-bands used for the interval. The distribution in each interval provides diversity of frequency for each encoded packet sent in the interval and can improve the decoding performance. The distribution in one interval can be executed in various ways. In one embodiment, the bits for all the encoded packets to be sent in a certain interval are first mapped to data symbols, and then the data symbols are mapped in the sub-bands used for the interval in a permuted manner. For the sub-band symbol mapping, a first sequence is initially formed with S 'sequential values, or S'-l. Then a second sequence of S 'values is created in such a way that the i-th value in the second sequence is equal to the inverse bit of the i-th value in the first sequence. All values that are equal to or greater than S ' in the second sequence they are eliminated in order to obtain a third sequence with S values that oscillate from 0 to S-l. Then, each value in the third sequence is incremented by one to obtain a sequence of S permuted index values that range from 1 to S, which is denoted by F (j). The j-th data symbol in the interval can be mapped to the F () -th subband in the interlace used for the interval. For example, if S = 500 and S '= 512, then the first sequence is. { 0, 1, 2, 3, .-., 510, 511.}. , the second sequence is. { 0, 256, 128, 384, ..., 255, 511.}. , and the third sequence is. { 0, 256, 128, 384, ..., 255.}. . The sequence F (j) only needs to be calculated once and can be used for all intervals. Other mapping schemes can also be used for subband symbol mapping in order to achieve the distribution in each interval. In general, each data stream can carry any number of data packets in each super-frame, depending on the data rate of the flow. Each data stream is assigned a sufficient number of intervals in each super-frame based on its data rate, subject to the availability of intervals and possibly other factors. For example, each data flow may be restricted to a maximum number specified intervals in each symbol period, which may be dependent on the mode used for the data flow. Each data flow may be limited to a specified maximum data rate, which is the maximum number of information bits that can be transmitted in each symbol period for the data flow. The maximum data rate is typically established by the decoding and temporary memory capabilities of the wireless devices. Restricting each data flow so that it is within the maximum data rate ensures that the data flow can be recovered by wireless devices that have the prescribed decoding and temporary memory capabilities. The maximum data rate limits the number of data packets that can be transmitted in each symbol period for the data flow. Then, the maximum number of intervals can be determined by the maximum number of data packets and the mode used for the data flow. In one embodiment, each data stream can be assigned an integer number of intervals in any given symbol period, and multiple data streams do not share an interleaving. For this modality, data flows can be sent up to M-l by the M-l data intervals in each period of symbols, assuming that an interval is used for the FDM pilot. In another modality, multiple data streams can share an interleaving. Figure 9A shows a block diagram of a mode of the TX data processor 120 in the base station 110. The TX data processor 120 includes T data flow processors TX 910a to 910t for the T data streams, a complementary information data processor 930 of TX for complementary control / information data, a pilot processor 932 for the TDM and FDM pilots, and a multiplexer (Mux) 940. Each TX data stream processor 910. processes a respective data flow. { d2} to generate a corresponding data symbol stream. { And ±} , for i e. { 1..T} . In each TX data stream processor 910, an encoder 912 receives and encodes the data packets for its data flow. { gave} and provides encoded packages. The encoder 912 performs the coding according to, for example, a concatenated code comprised of an external Reed-Solomon code and a Turbo code or internal convolutional code. In this case, the encoder 912 encodes each block of Krs data packets to generate Ns encoded packets, as shown in Figure 6. The coding increases the reliability of the transmission for the data flow. The encoder 912 can also generate and append a cyclic redundancy check (CRC) value to each encoded packet, which can be used by a wireless device for error detection (i.e., to determine whether the packet is decodes correctly or in error). The encoder 912 can also randomly distribute the encoded packets. A distributor 914 receives the encoded packets from the encoder 912 and distributes the bits in each encoded packet in order to generate a distributed packet. The distribution provides diversity of time and / or frequency for the package. Then, a temporary interval memory 916 is filled with distributed packets for all the ranges assigned to the data flow, for example, for example, as shown in Figure 8A or 8B. A scrambler 918 receives and encrypts the bits for each interval with a PN sequence in order to randomize the bits. M different PN sequences can be used for the M interval indices. The M PN sequences can be generated, for example, with a feedback displacement register linear (LFSR) that implements a particular generator polynomial, for example, g (x) = x15 + x14 + 1. The LFSR can be loaded with a different initial value of 15 bits for each interval index. In addition, the LFSR can be reloaded at the beginning of each symbol period. The encryptor 918 can execute an exclusive OR in each bit in a range with one bit in the PN sequence to generate an encrypted bit. A bit-to-symbol mapping unit 920 receives the encrypted bits for each range derived from the scrambler 918, maps these bits into modulation symbols according to a modulation scheme (eg, QPSK or 16-QAM) selected for the flow of data, and provides data symbols for the interval. Symbol mapping can be achieved by (1) grouping sets of B bits to form B bits of B bits, where B = l, and (2) mapping each binary value of B bits into a complex value for a point in a constellation of Signals for the modulation scheme. The outer and inner codes for the encoder 912 and the modulation scheme for the mapping unit 920 are determined by the mode used for the data flow. If the data flow is sent using hierarchical coding, then the base flow can be processed by a set of processing units 912 to 920 to generate a first stream of modulation symbols, and the enhancement stream can be processed by another set of processing units 912 to 920 in order to generate a second stream of modulation symbols (not shown in Figure 9 for simplicity). The same coding and modulation scheme can be used for both the base flow and the improvement flow, as shown in Table 1, or different coding and modulation schemes can be used for the two flows. Then, a combiner may receive and combine the first and second modulation symbol streams to generate the data symbols for the data stream. Hierarchical coding can also be executed in other ways. For example, the bits encrypted for both the base stream and the enhancement stream can be provided to a single symbol-to-symbol mapping unit that provides the data symbols for the data stream. A interleaved interval mapping unit 922 maps each assigned slot in the data stream. { gave } in the appropriate interleaving based on the interleaving interval mapping scheme used by the system (for example, as shown) in Figure 5). Then, a sub-band symbol mapping unit 924 maps the S data symbols in each interval into the appropriate sub-bands in the interleaving to which the interval is mapped. The mapping of symbols in sub-band can be done in order to distribute the S data symbols in the S sub-bands used for the interval, as described previously. The mapping unit 924 provides data symbols for the data flow. { gave } , which are mapped into the appropriate subbands used for the data flow. The TX supplementary information data processor 930 processes control data / supplementary information in accordance with a coding and modulation scheme used for complementary control / information data and provides supplementary information symbols. The pilot processor 932 executes processing for the TDM and FDM pilots and provides pilot symbols. The multiplexer 940 receives the mapped data symbols for the T data streams from the TX data stream processors 910a to 910t, the complementary information symbols from the TX complementary information data processor 930, the pilot symbols from the 932 pilot processor, and guard symbols. The multiplexer 940 provides the data symbols, supplementary information symbols, pilot symbols, and guard symbols in the sub-bands. and symbol periods based on a MUX_TX control derived from controller 140 and output a composite stream of symbols,. { Yc} . Figure 9B shows a block diagram of one mode of the modulator 130 in the base station 110. The modulator 130 includes a reverse fast Fourier transform unit 950 (IFFT - inverse Fourier transform phase) and a cyclic prefix generator 952. For each symbol period, the IFFT unit 950 transforms the N symbols for the N total subbands in the time domain with an IFFT of N points in order to obtain a "transformed" symbol containing N samples in the time domain. To combat the interference of symbols (ISI intersymbol interference), which is caused by the selective fading of frequencies, the generator 952 of cyclic prefixes repeats a portion (or C samples) of each transformed symbol to form a corresponding OFDM symbol that contains N "+ C samples The repeated portion is often called a cyclic prefix or guard interval. For example, the length of the cyclic prefix can be C = 512 for N = 4096. Each OFDM symbol is transmitted in a period of OFDM symbols (or simply, symbol period), which is N + C sample periods . The cyclic prefix generator 952 provides an output sample stream. { Y} for the compound symbol flow. { Yc} . Figure 10A shows a block diagram of a mode of the demodulator 160 in the wireless device 150. The demodulator 160 includes a cyclic prefix removal unit 1012, a Fourier transform unit 1014, a channel calculator 1016, and a detector 1018. The cyclic prefix elimination unit 1012 removes the cyclic prefix in each received OFDM symbol and provides a sequence of N input samples,. { x (n) } r for the received OFDM symbol. The Fourier transform unit 1014 performs a partial Fourier transform on the input sample sequence. { x (n) } for each selected interleaving m and provides a set of S received symbols,. { Xm (k)} , for that interleaving, where m = 1 ... M. The channel calculator 1016 derives the channel gain calculation. { ñm (k.}..}. for each selected interlace m based on the input sample sequence. { x (n) } . The detector 1018 performs detection (eg, equalization or matching filtering) on the set of S received symbols. { Xm (k)} for each selected interlace with the channel gain calculation. { ñm (k)} for that interleaving and provides S detected data symbols. { ? m (k)} for the interlaced. Figure 10B shows a block diagram of an RX 170 data processor mode in a wireless device 150. A multiplexer 1030 receives the detected data symbols for all the interleaves from the detector 1018, multiplexes the detected data and complementary information symbols for each symbol period based on the control of MUX_RX, provides each flow of detected data symbols of interest to a respective RX data stream processor 1040, and provides a flow of complementary information symbols detected to a processor 1060 of complementary information data of RX. In each RX data stream processor 1040, a symbol subband demapping unit 1042 maps the symbol received by each subband in a selected interleaving to the appropriate position within of an interval. A 1044 interval interleaving demapping unit maps each selected interleaving in the appropriate range. A bit symbol demapping unit 1046 maps the symbols received for each interval into code bits. A decrypter 1048 decrypts the code bits for each interval and provides decrypted data. A temporary buffer 1050 places one or more decrypted data intervals in temporary memory, performs the reassembly of packages as necessary, and provides decrypted packages. A grouper 1052 groups each decrypted packet and provides a grouped packet. A decoder 1054 decodes the bundled packets and provides decoded data packets for the data stream. { dx} . In general, the processing performed by the units within the processor 1040 of the RX data stream is complementary to the processing performed by the corresponding units within the TX data stream processor 910 in Figure 9A. The demapping of bit symbols and decoding are performed according to the mode used for the data flow. The XX complementary information data processor 1060 processes the symbols of complementary information received and provides data of decoded supplementary information. Due to the periodic structure of the interleaved Ms, the Fourier transform unit 1014 can execute a Fourier transform of S 'points for each selected interleave m so as to obtain the set of S received symbols. { Xm (k)} for that interlacing. The Fourier transform for the S 'subbands that include all the S subbands of the interlaced m, where m = 1 ... M can be expressed as: X (M - k + m) =? X (ri) - W, (M-k + m) n? ' «= I for J = 1 S 'Eq. (1) =? x (n) - W n = \ • where x (n) is the entry sample for the period of sample n, W¡f = , and N = M-S '. The following terms can be defined: xm (n) = x (r7) - W '", for n = 1 ... N, and Ec (2) Ml gm (r>) =? X, As''i + n) r for n = l ... S ', Ec (3)? = 0 where Xn is a rotated sample obtained by rotating the input sample x (n) by W '™ = , which is a phasor that varies from sample to sample (-1 in the exponent) for the terms m-l and n-1 it is due to an index numbering scheme that begins with 1 instead of 0); and gm (n) is a value in the time domain obtained by accumulating M rotated samples that are spaced by S 'samples. Equation (1) can be expressed as: Xn k) = X (M-k + m) =? Gm (n) -W *! ', For Jc = l ... S' Ec (4) »=? A partial Fourier transform of S 'points for interleaving m can be performed as explained below. Each of the N input samples in the sequence. { x (n) } for a period of symbols, it is first rotated by f, as shown in equation (2), in order to obtain a sequence of N rotated samples. { xm (n) } . Then, the rotated samples are accumulated, in S 'sets of M samples rotated, to obtain S' values in the time domain. { gm (n)} t as shown in equation (3). Each set contains each S'-th sample rotated in the sequence. { xm (n) } r associated the S 'sets with different initial rotated samples in the sequence. { xm (n) } . Then, a normal Fourier transform of S 'points is executed at the S' values in the time domain. { gm (n)} in order to get the Sr symbols received for the interlacement m. The symbols received for the S usable subbands are maintained, and the symbols received for the S'-S unused subbands are discarded. For the channel calculation, a partial Fourier transform of S 'points may be executed on the N input samples for the interleaving p used for the FDM pilot in order to obtain a set of S received pilot symbols,. { XP (k)} or X (M- Jc-fp). The modulation in the received pilot symbols is then eliminated to obtain channel gain calculations. { Ñp (k)} for the subbands in the interlaced p, as explained below: ñp (k) = Ñ (M - k + p) = X (M - Jc - fp) - P * (M - Jc + p), for J = 1 ... S ', Eq. (5) where P (M- k + p) is the known pilots symbol for the Jc-th subband in the interlace and p "*" is a complex conjugate. Equation (5) assumes that all S 'subbands are used for pilot transmission. Then an IFFT of S 'points is executed in the channel gain calculations. { Hp (k)} so as to obtain a sequence of S 'modulated channel gain values in the time domain. { hp (n)} r which can be expressed as: hp (n) = h (n) - Wmn ^ r for n = 1 ... S '. The channel gain values in the sequence. { . { n)} they are then de-rotated by multiplication with üT ™ ^, for n = 1 ... S '. The channel gain values in the sequence. { hp (n)} they are then de-rotated by multiplying with Wmnn in order to obtain a sequence of S 'de-rotated values of channel gain with domain at time h (n) ~ hp. { n) -, for n = 1 S 'The channel gain calculations for the subbands in the interleaving m can then be expressed as: ñm (k) = ñ. { M-k + m) = = h. { n) -WN (M- k + m) n for J = 1 Ec (6) »=? As indicated in equation (6), the channel gain calculations for the subbands in the interleaving m can be obtained by first multiplying each des-rotated gain value in the time domain in the sequence. { h (n) } by W ™ ^ in order to obtain a sequence of S 'rotated channel gain values,. { hm (n)} . Then a normal FFT of S 'points is executed in the sequence. { hm (n)} in order to obtain S 'channel gain calculations for the subbands in the interlaced m. The de-turn of hp (n) by ftTpnN and the spin of h (n) by 0 can be combined, so that the rotated channel gain values for the interlace m can be obtained as hm (n) -hp (n) - (m_p) N, for n = 1 ... S '. Previously, a channel calculation scheme has been described by way of example. The channel calculation can also be executed in other ways. For example, the channel calculations obtained for different interleavers used for pilot transmission may be filtered (for example, over time) and / or post-processed (for example, based on a least squares calculation of the response). of impulses { h (n).}.) in order to obtain a more accurate channel calculation for each interlacing of interest. The multiplexing techniques described herein 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 unit used to execute the multiplexing in a base station can be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), programmable field gate arrays (FPGAs - field programmable gate) arrays), processors, controllers, microcontrollers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. The processing units used to execute the complementary processing in a wireless device may also be implemented within one or more ASICs, DSPs, and so on. For a software implementation, multiplexing techniques can 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 142 or 182 in Figure 1) and executed by a processor (e.g., controller 140 or 180). The memory unit can be implemented inside the processor or external to the processor, in which case it can be communicatively coupled to the processor by various means as is known in the art. The above description of the described embodiments is provided in order 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 the person 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 is intended to encompass the broadest scope consistent with the principles and novel features described herein.

Claims (47)

CLAIMS Having described the invention as an antecedent, the content of the following claims is claimed as property:

1. A method for transmitting data in a multiple-carrier wireless communications system, characterized in that it comprises: assigning intervals to each plurality of data symbol flows, where each interval is a transmission unit • and a plurality of intervals are multiplexed by division of data. frequency in each period of symbols; multiplexing the data symbols in each data symbol stream over the ranges assigned to the data symbol stream; and forming a stream of compound symbols with multiplexed data symbols for the plurality of data symbol streams, wherein the plurality of data symbol streams are independently recoverable by a receiver.

The method according to claim 1, further characterized in that it comprises: forming a plurality of non-superimposed interleaves with U usable frequency sub-bands for the transmission, where U > 1 and each interleaving is a different set of frequency sub-bands selected from among the frequency sub-bands; and mapping the plurality of intervals in each symbol period in the plurality of interlaces.

The method according to claim 1, further characterized by comprising: forming 2N interleaved non-overlapping with a plurality of frequency subbands usable for transmission, where N = 1 each interleaved is a different set of frequency sub-bands selected from the plurality of frequency subbands; and mapping the plurality of intervals in each symbol period in the interlaced 2Ns.

The method according to claim 3, characterized in that N is equal to, 2, 3 or 4.

The method according to claim 2, characterized in that forming the plurality of non-superimposed interlaces comprises forming the plurality of interlaces with the same number of frequency subbands.

6. The method according to claim 2, characterized in that forming the plurality of non-superimposed interlaces comprises: forming the plurality of interleaves with the frequency sub-bands in each interleaving that is interleaved with the frequency sub-bands in each remaining interlace.

The method according to claim 2, characterized in that forming the plurality of non-superimposed interleaves comprises: forming a plurality of groups of frequency sub-bands, each group including sub-bands of frequencies evenly distributed in the T sub-bands of total frequencies in the system, where T > U, and forming each interleaving with frequency sub-bands selected from a respective group of frequency sub-bands.

The method according to claim 2, characterized in that assigning the slots to each plurality of data symbol streams comprises assigning to each plurality of interlaces a stream of data symbols, if at all, in each symbol period.

The method according to claim 2, wherein the plurality of intervals in each symbol period is identified by the interval indices, characterized in the method because it further comprises: for each symbol period, map the interval indices in the interleaving plurality based on a mapping scheme.

The method according to claim 9, characterized in that the mapping of the interval indices in the plurality of interleaves comprises: mapping each interval index used for the transmission of data to different indices of the plurality of interleaves in different periods of symbols.

The method according to claim 2, further characterized in that it comprises: distributing the multiplexed data symbols in each assigned interval in the frequency sub-bands in the interleaving in which the interval is mapped.

The method according to claim 11, characterized in that distributing the multiplexed data symbols in each assigned interval comprises: distributing the data symbols for each data packet sent in the interval in the frequency subbands in the interleaving in which it is mapped the interval.

The method according to claim 2, further characterized in that it comprises: selecting intervals for the pilot transmission from among the plurality of intervals in each symbol period; And multiplex the pilot symbols at the intervals used for data transmission.

The method according to claim 13, further characterized in that it comprises: mapping the intervals used for the pilot transmission in different interleaves in different periods of symbols.

The method according to claim 13, further characterized in that it comprises: mapping the plurality of intervals in each symbol period in the plurality of interlaces such that the interlaces used for the pilot transmission have variable distances to the interlaces used for the data transmission.

The method according to claim 9, further characterized in that it comprises: assigning at least one interval index for the pilot transmission; and assign the remaining interval indices for data transmission.

17. The method according to claim 16, further characterized in that it comprises: mapping at least one interval index used for the pilot transmission to at least one predetermined interleaving; and mapping each interval index used for the transmission of data in different interleaves in different periods of symbols.

The method according to claim 1, further characterized in that it comprises: processing a plurality of data streams to obtain the plurality of data symbol streams, a data symbol stream for each data stream.

The method according to claim 1, characterized in that assigning the slots to each plurality of data symbol flows comprises: assigning a particular number of slots to each data symbol stream based on at least one packet size and at least a coding and modulation scheme used for the flow of data symbols.

The method according to claim 18, characterized in that processing the plurality of data streams comprises: coding data packets for each data stream according to a coding scheme for generate coded packets for the data flow; and modulating the encoded packets for each data stream according to a modulation scheme to generate data symbols for the corresponding data symbol stream.

The method according to claim 18, characterized in that, coding the data packets for each data stream comprises encoding an integer number of data packets for each data stream in each frame of a predetermined time period, and assigning the ranges Each plurality of data symbol streams comprises assigning an integer number of slots to each data symbol stream in each frame based on the number of data packets that are transmitted in the frame for the corresponding data stream.

The method according to claim 1, characterized in that assigning the ranges to each plurality of data symbol flows comprises: assigning to each data symbol stream a particular number of intervals determined in decoding the restriction and a coding and modulation scheme used for the flow of data symbols.

23. An apparatus in a multiple carrier wireless communications system, characterized in that it comprises: an operating controller for assigning intervals to each plurality of data symbol streams, wherein each interval is a transmission unit and a plurality of frequency multiplexes are multiplexed by frequency division. intervals in each symbol period; and an operating data processor for multiplexing the data symbols in each data symbol stream in the ranges assigned to the data symbol stream and for forming a stream of composite symbols with multiplexed data symbols for the plurality of streams of symbols of data. data, wherein the plurality of data symbol flows are independently recoverable by a receiver.

The apparatus according to claim 23, characterized in that the controller is also operative to form a plurality of non-superimposed interleaves with U sub-bands of frequencies usable for transmission, where U >1, and to map the plurality of intervals in each symbol period in the plurality of interleaves, each interleaving being a different set of frequency sub-bands selected from among the U frequency sub-bands.

The apparatus according to claim 24, characterized in that the plurality of intervals in each symbol period is identified by the interval indices, and where the data processor is also operative, for each symbol period, mapping the interval indices in the plurality of interlaces based on a mapping scheme.

The apparatus according to claim 23, characterized in that the controller is also operative to select the intervals for the pilot transmission from among the plurality of intervals in each symbol period, and where the data processor is also operative to multiplex the symbols of pilot in the intervals used for the pilot transmission.

The apparatus according to claim 23, characterized in that the controller is further operative to assign a particular number of slots to each data symbol stream based on at least one packet size and at least one coding and modulation scheme used for the flow of data symbols.

28. The apparatus according to claim 23, characterized in that the data processor is also operative to process a plurality of data streams in order to obtain the plurality of data symbol streams, a stream of data symbols for each data stream.

29. The apparatus according to claim 23, characterized in that the multiple carrier wireless communications system uses orthogonal frequency division multiplexing (OFDM).

30. The apparatus according to claim 23, characterized in that the multiple carrier wireless communications system is an emission system.

31. An apparatus in a multiple-carrier wireless communication system, characterized in that it comprises: means for assigning intervals to each plurality of data symbol streams, wherein each interval is a transmission unit and a plurality of frequency multiplexes are multiplexed by frequency division. intervals in each symbol period; means for multiplexing the data symbols in each data symbol stream at the intervals allocated in the data symbol stream; and means for forming a stream of compound symbols with multiplexed data symbols for the plurality of data symbol streams, where the plurality of data symbol streams are independently recoverable by a receiver.

32. The apparatus according to claim 31, further characterized in that it comprises: means for forming a plurality of non-superimposed interleaves with U sub-bands of frequencies usable for transmission, where U > 1 and each interleaving is a different set of subbands of frequencies selected from among the U frequency subbands; and means for mapping the plurality of intervals in each symbol period in the plurality of interlaces.

The apparatus according to claim 32, wherein the plurality of intervals in each symbol period is identified by interval indices, further characterized by the apparatus because it comprises: means for mapping the interval indices in the plurality of interlaces for each period of symbols based on a mapping scheme.

34. The apparatus according to claim 31, further characterized in that it comprises: means for selecting the intervals for the pilot transmission from among the plurality of intervals in each symbol period; and means for multiplexing the pilot symbols at the intervals used for the pilot transmission.

35. The apparatus according to claim 31, further characterized in that it comprises: means for processing a plurality of data streams to obtain the plurality of data symbol streams, a data symbol stream for each data stream.

36. A method for receiving data in a multiple-carrier wireless communications system, characterized in that it comprises: selecting at least one data stream for recovery from among a plurality of data streams transmitted by a transmitter in the system; determining the intervals used for each selected data stream, where each interval is a transmission unit and a plurality of intervals is multiplexed by frequency division in each symbol period, where the data symbols for each plurality of data streams are multiplexed at intervals allocated to the data flow, and where the plurality of data streams are independently recoverable by a receiver; multiplexing the detected data symbols obtained for intervals used for each selected data stream in a stream of detected data symbols, where each detected data symbol is a calculation of a data symbol and at least one data symbol stream is obtained detected for at least one data stream selected for recovery; and processing each stream of detected data symbols to obtain a corresponding decoded data stream.

37. The method according to claim 35, further characterized in that it comprises: mapping the plurality of intervals in each symbol period into a plurality of non-superimposed interleaves formed with U sub-bands of frequencies usable for transmission, where U > 1 and each interleaving is a different set of subbands of frequencies selected from among the U frequency subbands.

38. The method according to claim 37, characterized in that the plurality of intervals in each symbol period is identified by interval indices, and where mapping the plurality of intervals in each symbol period comprises: mapping the interval indices in the plurality of interlaces in each period of symbols based on a mapping scheme.

39. The method according to claim 36, further characterized in that it comprises: performing a partial Fourier transform for each interval used for each selected data stream in order to obtain the data symbols received for the interval, the partial Fourier transform being a Fourier transform for less than all the subbands of frequencies in the system; and performing the detection on the received data symbols for each interval used for each selected data stream in order to obtain the symbols detected for the interval.

40. The method according to claim 36, further characterized in that it comprises: performing a partial Fourier transform for each interval used for the pilot transmission in order to obtain a channel calculation for the interval.

41. The method according to claim 40, further characterized by comprising: deriving a channel calculation for each interval used for each data flow selected based on the channel calculations obtained from the intervals used for the pilot transmission.

42. An apparatus in a multiple-carrier wireless communication system, characterized in that it comprises: an operating controller for selecting at least one data stream for retrieval from a plurality of data streams transmitted by a transmitter in the system and for determining the intervals used for each selected data stream, where each interval is a transmission unit and a plurality of intervals are multiplexed by frequency division in each symbol period, where the data symbols for each plurality of data streams are multiplexed into intervals assigned to the data flow, and where the plurality of data flows are independently recoverable by a receiver; and an operating processor for multiplexing the detected data symbols obtained for the intervals used for each selected data stream in a stream of detected data symbols and for processing each stream of detected data symbols in order to obtain a data stream corresponding decoded, where each detected data symbol is a calculation of a data symbol and at least one detected data symbol stream is obtained for at least one data stream selected for recovery.

43. The apparatus according to claim 42, characterized in that the controller is further operable to map the plurality of intervals in each symbol period into a plurality of non-superimposed interleaves formed with U sub-bands of frequencies usable for transmission, where ü > 1 and each interleaving is a different set of subbands of frequencies selected from among the U frequency subbands.

44. The apparatus according to claim 42, further characterized in that it comprises: a demodulator operative to perform a partial Fourier transform for each interval used for each selected data stream in order to obtain the data symbols received for the interval and to perform the detection on the received data symbols for each interval used for each selected data flow in order to obtain symbols detected for the interval.

45. A device in a system wireless multiple carrier communications, characterized in that it comprises: means for selecting at least one data stream for retrieval from among a plurality of data streams transmitted by a transmitter in the system; means for determining the intervals used for each selected data stream, where each interval is a transmission unit and a plurality of intervals in each symbol period is multiplexed by frequency division, where the data symbols for each plurality of data streams they are multiplexed at intervals assigned to the data stream, and where the plurality of data streams are independently recoverable by a receiver; means for multiplexing detected data symbols obtained for the intervals used for each selected data stream in a stream of detected data symbols, where each detected data symbol is a calculation of a data symbol and at least one flow of symbols is obtained of data detected for at least one data flow selected for recovery; and means for processing each stream of detected data symbols to obtain a data stream corresponding decoding.

46. The apparatus according to claim 45, further characterized in that it comprises: means for mapping the plurality of intervals in each symbol period into a plurality of non-superimposed interleaves formed with ü sub-bands of frequencies usable for transmission, where U > 1 and each interleaving is a different set of subbands of frequencies selected from among the U frequency subbands.

47. The apparatus according to claim 45, further characterized in that it comprises: means for performing a partial Fourier transform for each interval used for each selected data stream in order to obtain the data symbols received for the interval; and means for performing detection on the received data symbols for each interval used for each selected data stream in order to obtain symbols detected for the interval.