KR101507782B1 - Method of data processing and transmitter in mobile communication system - Google Patents

Abstract

To a data processing method and a transmitter for signal transmission through a multiple transmission antenna at a transmission side in a wireless communication system. As one aspect of the present invention, a method is disclosed in which, when transmitting a transmission signal using multiple antennas in a wireless communication system, one codeword is spatially divided after symbol mapping. When one codeword is divided into two or more code blocks and channel-coded, in order to obtain a spatial diversity effect, it is preferable to distribute the symbols to the space division function alternately to the layers when performing space division before interleaving.

Wireless communication, OFDM, MIMO, transmission chain, space diversity

Description

TECHNICAL FIELD [0001] The present invention relates to a data processing method and a transmitter in a wireless communication system,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system, and more particularly, to a data processing method and a transmitter for transmitting a signal through a multiple transmission antenna at a transmission side in a wireless communication system.

Recently, studies on orthogonal frequency division multiplexing (OFDM) and multi-input multi-output (MIMO) antenna technology have been actively conducted as a base technology of a wireless communication system.

The basic principle of OFDM is to divide a serial data stream having a high-rate into a plurality of parallel data streams having a slow-rate, and use a plurality of carriers to transmit parallel data streams And transmit them at the same time. In other words, the data stream having the high-speed data rate is converted into a data stream having a plurality of low data rates through a serial-to-parallel converter, and each subcarrier is multiplied After each data stream is combined, it is transmitted to the receiving end. Each of the plurality of carriers is referred to as a sub-carrier. In the OFDM scheme, orthogonality exists between a plurality of carriers. Therefore, even if frequency components of carriers overlap each other, detection at the receiving end is possible.

A plurality of parallel data streams generated by the serial-to-parallel conversion unit can be transmitted on a plurality of subcarriers by an IDFT (Inverse Discrete Fourier Transform), and the IDFT is subjected to Inverse Fast Fourier Transform (IFFT) Can be efficiently implemented by using < RTI ID = 0.0 >

The symbol duration of a subcarrier having a low data rate is increased, so that the relative signal dispersion in time caused by multipath delay spreading is reduced. Inter-symbol interference can be reduced by inserting a guard interval longer than the delay spread of a channel between OFDM symbols. Also, if a part of the OFDM signal is copied in the guard interval and placed at the beginning of the symbol, the OFDM symbol can be cyclically extended to protect the symbol.

The orthogonal frequency division multiple access (OFDMA) scheme refers to a multiple access method in which a plurality of subcarriers available for a system using OFDM as a modulation scheme are provided to each user to realize multiple access. OFDMA provides a frequency resource called a sub-carrier to each user, and each frequency resource is provided to a plurality of users independently of one another and does not overlap with each other. Eventually, the frequency resources are allocated mutually exclusive.

FIGS. 1A and 1B are block diagrams for explaining a data processing procedure at a transmitting end and a receiving end, respectively, according to the OFDMA scheme according to the related art.

Referring to FIG. 1A, on the transmitting side, symbol constellation mapping is performed on a bit stream for each user according to a modulation technique such as quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM), or 64 QAM. [S11]. At least two or more bits are mapped to one symbol by symbol mapping.

The bit stream is mapped to data symbols, and the data symbols are converted into parallel data symbols through a serial / parallel converter (S12). The data symbols are converted into parallel symbols corresponding to the number of subcarriers Nu (n) allocated to each user n by the serial-to-parallel conversion. As shown in FIG. 1A, a data symbol of a user 1 is converted into Nu (1) parallel symbols, which is the number of carriers allocated to the user 1. Since the sub-carriers allocated to each user n may be the same or different from each other, the data symbols of the respective users may be converted into the same or different numbers of parallel symbols Nu (n).

The data symbols for the specific user transformed in parallel are mapped to Nu (n) subcarriers allocated to a specific nth user among all Nc carriers, and the remaining Nc- (Nu (n) The data symbols of the user are mapped (S13). By a symbol to subcarrier mapping module that maps the symbols to a carrier, the user's unassigned subcarrier is filled with zero (zero padding). The output of the mapping to subcarrier mapping module is converted to time domain signals by an Nc-point Inverse Fast Fourier Transform (IFFT) module [S14].

A cyclic prefix (CP) is inserted in the OFDM symbol output from the IFFT module to reduce inter-symbol interference (ISI) [S15]. The CP-inserted OFDM symbols are transmitted to the receiving side after performing parallel-to-serial conversion (S16).

Referring to FIG. 1B, the process of data processing on the receiving side according to the OFDMA scheme according to the related art proceeds in the reverse of the process of data processing on the transmitting side as shown in FIG. 1A. The received data symbols are subjected to S / P conversion and Nc-point FFT and are then subcarrier-to-symbol mapped. The parallel symbols are converted into serial data, and the bit stream is outputted through the symbol demapping process.

The MIMO scheme is a method that improves the efficiency of data transmission and reception by employing multiple transmit antennas and multiple receive antennas by avoiding the use of one transmit antenna and one receive antenna. That is, a technique for increasing the capacity or improving the performance by using multiple antennas at the transmitting end and / or the receiving end of the wireless communication system. Hereinafter, the MIMO technique may be referred to as a multiple antenna technique or technique.

The multi-antenna technique is applied to a technique of collecting a piece of fragmentary data received from a plurality of antennas, without depending on a single antenna path, to receive a whole message. It is possible to improve the data transmission speed in a certain range or to increase the system range for a specific data transmission speed. The multi-antenna technology is a next generation mobile communication technology that can be widely used for mobile communication terminals and repeaters, and is attracting attention as a next generation technology capable of overcoming the limitation of the transmission capacity of mobile communication which is different from the limit situation due to expansion of data communication. Next generation mobile communication requires much higher data rate than existing mobile communication, so efficient multi-antenna technology is expected to be necessary.

Among various transmission efficiency enhancement technologies currently being studied, a multi-antenna (MIMO) technique using multiple antennas at both the transmitter and the receiver is a method for dramatically improving communication capacity and transmission / reception performance without additional frequency allocation or power increase. It is receiving the greatest attention.

2 is a schematic block diagram of a general multi-antenna system according to the prior art. As shown in FIG. 2, if the number of antennas is increased at the transmitting / receiving end, the theoretical channel transmission capacity increases in proportion to the number of antennas, unlike the case where a plurality of antennas are used only at the transmitter and the receiver. . After the theoretical capacity increase of the multi-antenna system was proved in the mid-90s, various techniques for bringing it up to practical data transmission rate have been actively researched so far. Some of these technologies have already been applied to 3G mobile communication and next generation wireless LAN And is reflected in various standards of wireless communication.

The research trends related to multi-antennas to date include information theory studies related to calculation of multi-antenna communication capacity in various channel environments and multiple access environments, research on wireless channel measurement and modeling of multi-antenna systems, and improvement of transmission reliability and transmission rate And research on space-time signal processing technology for various applications.

The multi-antenna technique is classified into a spatial diversity scheme that increases transmission reliability using symbols that have passed through various channel paths, a spatial diversity scheme that simultaneously transmits a plurality of data symbols using a plurality of transmission antennas, (spatial multiplexing) method. In addition, researches on how to appropriately combine these two methods and obtain the merits of each of them have been conducted recently.

In the case of the space diversity scheme, there is a space-time block code sequence, a space-time trellis code sequence scheme which uses the diversity gain and the coding gain at the same time. In general, the bit error rate improvement performance and the code generation freedom are superior to the trellis coding scheme, but the space complexity coding is simple. The spatial diversity gain can be obtained by multiplying the number of transmission antennas by the number of reception antennas.

The spatial multiplexing scheme is a method of transmitting different data streams at each transmission antenna. At this time, mutual interference occurs between the data transmitted simultaneously from the transmitter and the receiver. The receiver removes this interference using appropriate signal processing techniques and receives it. The noise cancellation scheme used here is a maximum likelihood receiver, a ZF receiver, an MMSE receiver, a D-BLAST, and a V-BLAST. Particularly, when the channel information is known by a transmitter, a singular value decomposition (SVD) Method or the like can be used.

Finally, there is a combined technique of spatial diversity and spatial multiplexing. If only the spatial diversity gain is obtained, the performance gain is gradually saturated as the diversity order increases. If only the spatial multiplexing gain is used, the transmission reliability in the radio channel is degraded. In order to solve this problem, there have been studied methods of obtaining both of the gains. Among them, there are methods such as a space-time block code (Double-STTD) and a space-time BICM (STBICM).

In a typical communication system, in order to correct an error experienced by a channel, a receiver performs channel encoding using forward error correction code, and then transmits the information. The receiver demodulates the received signal and then decodes the error correction code to recover the transmission information. Through this decoding process, the error on the received signal caused by the channel is corrected.

All error correction codes have a maximum correctable limit at the time of channel error correction. That is, if the received signal has an error exceeding the limit of the error correcting code, the receiver can not decode it with errorless information. Therefore, the receiving end needs a basis for determining whether there is an error in the decoded information. Thus, a special type of encoding process is required for error detection separately from the error correction encoding process. A CRC code (Cyclic Redundancy Check code) is widely used as the error detection code.

CRC is one of coding methods used for error detection rather than error correction. Generally, transmission information is encoded using CRC, and then error correction codes are used for CRC encoded information.

Hereinafter, turbo codes among various channel coding techniques will be described. A turbo encoder consists of two recursive systematic convolution encoders and an interleaver. The interleaver is used to facilitate parallel decoding in actual implementation of the turbo code, which is a kind of QPP (quadratic polynomial permutation). This QPP interleaver is defined only for a specific data block size. Turbo code performance is known to be better as the data block size increases. However, in an actual communication system, a data block (for example, a transmission block) having a predetermined size or larger is divided into a plurality of small data blocks for the convenience of actual implementation. The divided small data block is called a code block. That is, one code word is divided into several code blocks if the length is long. One unit encoded with CRC and error correction codes is commonly referred to as a 'codeword', but the meaning of a codeword in this document is limited to one data block, for example, a transport block The data unit in which the channel coding is performed after the CRC is added is called a 'codeword'. Therefore, when the size of one transport block exceeds a predetermined reference value and is divided into two or more code blocks, the channel-encoded result of all the code blocks becomes one code word.

The code block generally has the same size, but because of the size limitation of the QPP interleaver, one of the code blocks may have different sizes. After performing an error correction coding process in units of code blocks, interleaving is performed to reduce the influence of burst errors in a transmission process on a wireless channel. Then, it is mapped and transmitted to the actual radio resources. Since the amount of radio resources used in actual transmission is constant, rate matching must be performed on the encoded code block in order to match the amount of radio resources. In general, rate matching is performed by puncturing or repetition. Rate matching may also be performed in units of code blocks encoded as in the 3GPP WCDMA system. Alternatively, the systematic part and the parity part of the encoded code block may be separated to perform rate matching separately. 3 is a diagram for explaining a process of performing rate matching by separating an information word portion and a parity portion of an encoded code block. In FIG. 3, rate matching can be performed according to the transmission start position and the data size to be transmitted in the circular buffer. In Figure 3, the code rate is assumed to be 1/3.

In the case of a MIMO system using spatial multiplexing, a method in which one codeword is transmitted in a plurality of transmission data streams is referred to as a single codeword (SCW), and a method in which one or more codewords are transmitted is referred to as a multi-codeword : multiple codeword). 4A and 4B are views for explaining the concepts of SCW and MCW. A hybrid configuration of SCW and MCW is also possible. For example, assuming four transmit antennas and four receive antennas, only two codewords can be used. In this case, two SCWs transmitting two data streams are connected to each other to constitute the MCW system.

FIG. 5 shows a coding chain used for HS-DSCH in a WCDMA system according to the prior art. When spatial multiplexing is used, a maximum of two data streams can be transmitted. Since the stream is transmitted to the MCW, the same coding chain can be used when one stream is transmitted and two streams are transmitted.

It is an object of the present invention to provide a data processing method for efficiently dividing one codeword into two or more layers when data is transmitted through multiple transmit antennas in a wireless communication system.

It is another object of the present invention to provide a method of processing data so that data can be transmitted through multiple transmit antennas to reduce fading in a wireless communication system.

A method is disclosed in which one codeword is spatially distributed in a wireless communication system in accordance with the present invention. Fading is one of the main causes of performance degradation in wireless communication systems. The channel gain value changes according to time, frequency, and space, and the lower the channel gain value, the greater the performance degradation becomes. Diversity, one of the ways to overcome fading, exploits the fact that the probability that multiple independent channels all have low gain values is very low. In general, the correlation of channel gain values between two points in time, frequency, and space becomes independent as the distance of time, frequency, and space becomes larger. Therefore, in order to overcome the fading, it is possible to obtain a gain by diversity by arranging the encoded bits into one code block so as to spread evenly over time, frequency, and space.

As one aspect of the present invention, a method is disclosed in which, when a transmission signal is transmitted using multiple antennas in a wireless communication system, one codeword is spatially divided after symbol mapping. When one codeword is divided into two or more code blocks and channel-coded, in order to obtain a spatial diversity effect, it is preferable to distribute the symbols to the space division function alternately to the layers when performing space division before interleaving. When spatial division is performed after interleaving, the symbols may be alternately distributed to the layers in the space division function, or may be simply divided into two or more symbol groups.

According to another aspect of the present invention, there is provided a data processing method for transmitting a signal through a multiple transmission antenna at a transmission side of a wireless communication system, the method comprising: performing channel coding on one data block And outputting a symbol stream by performing symbol mapping on a bit stream output from the data block, outputting a symbol stream, rearranging the order of symbols included in the symbol stream, Into at least two or more symbol groups and outputting the divided symbols.

According to still another aspect of the present invention, there is provided a data processing method for transmitting a signal through a multiple transmission antenna at a transmission side of a wireless communication system, the method comprising: performing channel coding on one data block And outputting a symbol stream by performing symbol mapping on a bit stream output from the data block and outputting a symbol stream; and outputting each symbol group by grouping the symbol streams into at least two or more symbol groups .

According to still another aspect of the present invention, there is provided a transmitter for transmitting signals through multiple transmit antennas in a wireless communication system, the transmitter including: a channel encoder for performing channel encoding on one data block; A symbol mapping module for performing symbol mapping on the channel-encoded and output bit stream to output a symbol stream; an interleaver for rearranging and outputting the order of the symbols included in the symbol stream; And a space division module for dividing the input signal into at least two or more symbol groups and outputting the divided signals.

According to another aspect of the present invention, there is provided a transmitter for transmitting a signal through multiple transmit antennas in a wireless communication system, the transmitter including: a channel encoder for performing channel encoding on a code block basis for one data block; A symbol mapping module for performing symbol mapping on the bit stream output from the data block and outputting a symbol stream, and a space allocation module for grouping the symbol streams into at least two or more symbol groups and outputting each symbol group Module. ≪ / RTI >

According to still another aspect of the present invention, there is provided a data processing method for transmitting a signal through a multiple transmission antenna at a transmission side of a wireless communication system, the method comprising: performing channel coding on one data block Performing bit interleaving on a bit stream output from the data block by channel coding, grouping the interleaved bit streams into at least two bit groups, and outputting each bit group; And performing symbol mapping for each bit group.

According to still another aspect of the present invention, there is provided a transmitter for transmitting signals through multiple transmit antennas in a wireless communication system, the transmitter including: a channel encoder for performing channel encoding on one data block; A spatial distribution module for grouping the interleaved bit streams into at least two bit groups and outputting each bit group; and an interleaver for interleaving the interleaved bit streams into at least two bit groups, And a symbol mapping module for performing symbol mapping on the received signal.

In the above embodiments of the present invention, the channel coding may be performed for each code block for the data block consisting of at least two code blocks.

According to the present invention, when one data block is divided into a plurality of code blocks and channel-encoded, sufficient space diversity can be given to each code block by adding a simple function to the transmission chain.

In the following, the structure, operation and other features of the present invention can be easily understood by the embodiments of the present invention described with reference to the accompanying drawings. The following embodiments are examples in which the technical features of the present invention are applied to an evolved universal mobile telecommunications system (E-UMTS). E-UMTS is also called Long Term Evolution (LTE) system. For details of the technical specifications of UMTS and E-UMTS, refer to Release 7 and Release 8 of "3rd Generation Partnership Project (Technical Specification Group Radio Access Network)" respectively.

FIG. 6 illustrates a structure of a downlink FDD (Frequency Division Duplex) subframe of an LTE system. Since the length of one subframe is as short as 1 ms, the change of the channel in the time axis is small, while the frequency axis can be used up to 20 MHz, and the change is large, and since the change to the space axis can be completely independent of the channel, It is necessary to uniformly distribute the signals on the frequency axis and the time axis to obtain the diversity gain. The embodiments of the present invention are applicable not only to the FDD but also to a TDD (Time Division Duplex) system having a subframe structure different from that of the FDD system.

7A and 7B illustrate a structure of a transmission chain according to an embodiment of the present invention. FIG. 7A shows a transmission structure of Rank 3 with three layers, FIG. 7B shows the number of layers Is a transmission structure of Rank 4 (Rank 4) having a value of 4.

The first transport block TB1 of FIG. 7A is connected to one stream, that is, one layer, through data processing according to a transmission chain. In other words, a CRC is added to one transport block according to a CRC attaching algorithm, and is then allocated to one layer through a channel encoding process. A transport block is a term used in a UMTS system or an E-UMTS system, which means a basic data unit exchanged through a transport channel. The channel coding may be performed by a convolution code, a turbo code, a Low Density Parity Check (LDPC) code, or the like.

In the case of the second transport block TB2 of FIG. 7A and the first and second transport blocks TB3 and TB4 of FIG. 7B, one transport block is connected to two streams, that is, two layers. When the size of one transport block exceeds a predetermined value, it is divided into a plurality of code blocks (CB) and processed. At this time, the CRC may be added in units of transmission blocks or in units of code blocks. It is also possible to add a CRC to each code block after the transmission block to which the CRC is added is divided into a plurality of code blocks. Channel coding is performed on a code block basis. A process of data processing considering space diversity is required in the process of assigning code blocks on which channel coding is performed to each layer. The symbol streams allocated to each layer are precoded for multi-antenna transmission and transmitted to the receiver through a plurality of transmit antennas.

7A and 7B, various embodiments related to data processing before each layer allocation after the channel encoding process will be described below.

8 is a diagram for explaining a transmission chain structure according to an embodiment of the present invention.

Referring to FIG. 8, channel-encoded code blocks CB1 and CB2 are composed of a systematic part and a parity part. The rate matching module 81 performs rate matching on the channel-encoded code blocks. Rate matching refers to a process of matching the size of channel-encoded code blocks to a predetermined value. For example, by controlling the transmission start position using the circular buffer of FIG. 3, the size of the code block to be transmitted can be adjusted. The rate matching may be performed for each channel-coded code block or for all of the code blocks connected thereto.

The spatial division module 82 divides the rate-matched bitstream into two bitstreams and outputs the divided bitstreams. At this time, the order of each bit of the bit stream is not changed. The number of bitstreams to be divided corresponds to the number of layers. 8 shows a case where the number of layers is two.

Each divided bit stream is input to each of the symbol mapping modules 83a and 83b. Each of the symbol mapping modules 83a and 83b performs symbol mapping to output a symbol sequence. A modulation scheme such as quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM), or 64 QAM may be used as a symbol mapping method, but the present invention is not limited thereto.

The symbol streams output from the symbol mapping modules 83a and 83b are input to the respective interleavers 84a and 84b. Each interleaver 84a and 84b performs interleaving on each symbol stream to rearrange the order of the symbols. The interleaving is preferably OFDM symbol based interleaving. OFDM symbol-based interleaving means a method of interleaving symbols allocated to subcarriers within one OFDM symbol. The order of the symbols allocated to the subcarriers is rearranged by OFDM symbol based interleaving. Each symbol stream interleaved by each interleaver 84a, 84b is assigned to each layer.

9A is a diagram for explaining a transmission chain structure according to another embodiment of the present invention.

Referring to FIG. 9A, a rate matching module 91 performs rate matching on channel-encoded code blocks CB1 and CB2. The symbol mapping module 92 performs symbol mapping on the bit stream output from the rate matching module 91 to output a symbol stream. A specific description of the rate matching and symbol mapping can be referred to the description of FIG.

The interleaver 93 interleaves the symbol stream output from the symbol mapping module 92 to rearrange the order of the symbols. At this time, the interleaver 93 preferably performs interleaving so that the symbols corresponding to the code blocks CB1 and CB2 are uniformly mixed with each other. In other words, the symbol stream in which the channel-coded first code block CB1 is mapped and the symbol stream in which the second code block CB2 is mapped can be mixed evenly with each other as shown in FIG. 9A (b) Interleaving is performed. The order of rearrangement of symbols by interleaving is preferably set in advance according to a predetermined algorithm, and it is preferable to perform OFDM symbol-based interleaving, as in Fig.

The spatial division module 94 divides the symbol stream output from the interleaver 93 according to the number of layers and outputs the divided stream. Each divided symbol stream is assigned to each layer. In FIG. 9, the interleaver 93 and the spatial division module 94 are shown as physically independent components, but they can be integrally configured in actual implementation. That is, the interleaver 93 may perform interleaving and then divide it into a plurality of symbol streams and output them, thereby allocating each symbol stream to each layer.

9B is a view for explaining a transmission chain structure according to another embodiment of the present invention. In FIG. 9B, the rate matching is performed by the rate matching module 95 and the output data bit stream is input to the bit-level interleaver 96. FIG. The bit-level interleaver 96 performs interleaving on the input data bit stream. At this time, the interleaving is preferably performed in units of bit groups including one or more bits. The number of bits included in each bit group is equal to the number of bits mapped to one symbol in the first and second symbol mapping modules 98a and 98b. For example, when BPSK is used as a symbol mapping scheme in the first and second symbol mapping modules 98a and 98b, each bit group is composed of one bit, and when using QPSK, it is composed of two bits , Four bits when using 16QAM, and six bits when using 64QAM. 9B illustrates a case where QPSK is used as a symbol mapping scheme. The data bit stream written in the bit direction in the bit level interleaver 96 is divided into a plurality of bit groups And is read out.

The data bit stream output from the bit-level interleaver 96 is divided by the spatial division module 97 according to the number of layers. The first and second symbol mapping modules 98a and 98b perform symbol mapping on the data bit stream segmented by the spatial segmentation module 97, respectively. FIG. 9B shows a case where QPSK is used as a symbol mapping scheme, so that two bits are mapped to one symbol. In FIG. 9B, the spatial division by the spatial division module 97 and the symbol mapping by the first and second symbol mapping modules 98a and 98b may be changed. That is, after performing the symbol mapping on the data string output from the bit-level interleaver 96, the symbol string can be divided according to the number of layers.

In FIG. 9B, it can be confirmed that each symbol sequence output from the first and second symbol mapping modules 98a and 98b is the same as each symbol sequence output from the space division module 94 of FIG. 9A. Although the OS-based interleaver 93 of FIG. 9A performs interleaving at the symbol level and the bit-level interleaver 96 of FIG. 9B performs interleaving at the bit level, the bit-level interleaver 96 does not support the symbol mapping technique The interleaving is performed in units of a bit group consisting of a number of bits, which is equivalent to performing interleaving at the symbol level. Also, the spatial division module 97 shown in FIG. 9B has the same result as that of FIG. 9B even if it is located after one symbol mapping module as shown by 9a.

10A is a diagram for explaining a structure of a transmission chain according to another embodiment of the present invention. The structure of the embodiment of Fig. 10A is similar to the embodiment of Fig. 9A, except that the spatial division module 94 of Fig. 9A is replaced by the spatial distribution module 104. [ The spatial distribution module 104 does not merely divide the symbol stream output from the interleaver 103 according to the number of layers, but performs the process of rearranging the order of the symbols again in the dividing process. That is, in FIG. 10A, the interleaver 103 rearranges the order of symbols corresponding to each code block according to a predetermined interleaving algorithm, and then the spatial distribution module 104 divides a plurality of symbols The order of the symbols is readjusted in a predetermined manner. At this time, the spatial distribution module 104 may perform a spatial interleaving function. For example, one symbol stream may be composed and outputted by even-numbered symbols of a symbol stream corresponding to each code block, and another symbol stream may be composed and outputted by odd-numbered symbols. The method of reordering the symbols in the space allocation module 104 may be freely determined to the extent of maximizing the spatial diversity effect. In FIG. 10A, the interleaver 103 and the spatial distribution module 104 may be integrated in an actual implementation process. A specific description of the rate matching module 101, the symbol mapping module 102, and the interleaver 103 in FIG. 10 may be referred to in the description of FIG.

10B is a view for explaining a transmission chain structure according to another embodiment of the present invention. The embodiment of FIG. 10B is similar to the embodiment of FIG. 9B in that the bit-level interleaver 106 comprises at least one bit according to the symbol mapping technique used in the first and second symbol mapping modules 108a and 108b And differs from FIG. 10A in that interleaving is performed on a bit group basis. In addition, when the spatial distribution module 107 space-distributes the data bit stream according to the number of layers, the distribution is performed in units of bit groups used in the bit-level interleaver 106. In actual implementation, the bit-level interleaver 106 and the spatial distribution module 107 may be integrated and implemented. In addition, in FIG. 10B, the order of spatial distribution by the spatial distribution module 107 and symbol mapping by the first and second symbol mapping modules 108a and 108b may be changed. That is, even if the space distribution module 107 in FIG. 10B is located after one symbol mapping module as in 10a, the result is equivalent to the above.

11 is a view for explaining a transmission chain structure according to another embodiment of the present invention. Compared with the embodiment of FIG. 10A, the embodiment of FIG. 11 has a structure in which the spatial distribution module 113 and interleavers 114a and 114b are reversed in position. That is, the symbol stream output from the symbol mapping module 112 is divided into two symbol streams by the spatial distribution module 113. At this time, the spatial distribution module 113 rearranges the order of the symbols so that each divided symbol stream includes symbols corresponding to the code blocks CB1 and CB2 uniformly, while distributing the symbol streams output from the symbol mapping module 112 . The interleavers 114a and 114b interleave the respective symbol streams output from the spatial distribution module 113 to rearrange the symbols. The symbol streams output from the interleavers 114a and 114b are allocated to the respective layers. In the case of FIG. 11, the spatial distribution module 113 and the interleavers 114a and 114b may be integrated in actual implementation.

In the embodiments of FIGS. 8 and 11, as in the example of FIG. 9B or FIG. 10B, the bit-unit interleaving can be performed before the symbol mapping for the code-coded code blocks. That is, the code-encoded code blocks may be rearranged in the order of the bits included in the code blocks by performing interleaving on a bit-by-bit basis for each bit group.

In the embodiments of FIGS. 8 and 11, the case where OS-based interleaving is not used can be considered. In this case, too, considering the case where two code blocks are not allowed to be included in one symbol, Processing of units is simpler than processing of bits. For example, if the rate matched CB1 is 10 bits long, CB2 is 10 bits long, and 16QAM is used, one bit is formed by 4 bits, so that the last two bits of CB1 and the first two bits of CB2 are one 16QAM Symbol. If this is not allowed, the lengths of CB1 and CB2 should be limited to integer multiples of the modulation order. This case is the same as the case where OS-based interleaving was previously used for Identity Interleaving. Therefore, when the OS-based interleaving is not used, the operations of the symbol mapping module and the space division (or distribution) module proposed in the present invention are applied equally.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

FIGS. 1A and 1B are block diagrams for explaining a data processing procedure at a transmitting end and a receiving end, respectively, according to the OFDMA scheme according to the related art.

2 is a schematic block diagram of a general multi-antenna system according to the prior art.

3 is a diagram for explaining a process of performing rate matching by separating an information word portion and a parity portion of an encoded code block.

4A and 4B are views for explaining the concepts of SCW and MCW.

FIG. 5 shows a coding chain used for HS-DSCH in a WCDMA system according to the prior art.

6 shows a structure of a DL subframe in the LTE system.

7A and 7B illustrate a transmission chain structure of an LTE system according to an embodiment of the present invention.

8 is a diagram for explaining a transmission chain structure according to an embodiment of the present invention.

9A and 9B are views for explaining a transmission chain structure according to another embodiment of the present invention.

10A and 10B are views for explaining a structure of a transmission chain according to another embodiment of the present invention.

11 is a view for explaining a structure of a transmission chain according to another embodiment of the present invention.

Claims (24)

A data processing method for transmitting a signal through a multiple transmission antenna at a transmitting side of a wireless communication system, Performing channel coding on each code block for code blocks divided from a transport block and outputting a bit stream constituting a codeword; Performing a modulation on a bit stream constituting the codeword and outputting a symbol stream corresponding to the codeword; Performing Orthogonal Frequency Division Multiplexing (OFDM) symbol-based interleaving on the output symbol stream to rearrange the symbol order; Mapping the rearranged symbol streams into two or more layers in a predetermined order; And Performing precoding on a symbol stream mapped to the layers, and transmitting the precoded stream to a receiver through the multiple transmit antennas, Wherein the predetermined order is configured to be alternately mapped to the two or more layers in symbol units of a symbol stream corresponding to the codeword, Wherein the OFDM symbol based interleaving comprises interleaving symbols allocated to subcarriers in one OFDM symbol. The method according to claim 1, Wherein the two or more layers include a first layer and a second layer, Wherein the predetermined order is such that even-numbered symbols of the rearranged symbol stream are mapped to the first layer and odd-numbered symbols are mapped to the second layer. The method according to claim 1, If the number of the transmission blocks is two, the number of the code words is two, A symbol stream corresponding to a first codeword of the two codewords is divided into one layer and a symbol stream corresponding to a second codeword of the two codewords is divided into two layers according to the predetermined order to be mapped , And data processing method. The method of claim 3, Even symbols of a symbol stream corresponding to the second codeword are allocated to a first one of the two layers, And odd-numbered symbols of a symbol stream corresponding to the second codeword are mapped to a second one of the two layers. The method according to claim 1, If the number of the transmission blocks is two, the number of the code words is two, A symbol stream corresponding to a first codeword of the two codewords is transmitted to a first layer and a second layer, and a symbol stream corresponding to a second codeword of the two codewords is transmitted to a third layer and a fourth layer, respectively And the data is divided and mapped according to the predetermined order. 6. The method of claim 5, The even-numbered symbols of the symbol stream corresponding to the first codeword are mapped to the first layer and the odd-numbered symbols of the symbol stream corresponding to the first codeword are mapped to the second layer, Wherein even-numbered symbols of a symbol stream corresponding to the second codeword are mapped to the third layer and odd-numbered symbols of a symbol stream corresponding to the second codeword are mapped to the fourth layer. A transmitter for signal transmission on a transmitting side of a wireless communication system via multiple transmit antennas, A channel encoder for performing channel encoding on a code block basis for code blocks divided from a transport block and outputting a bit stream constituting a codeword; A symbol mapping module for performing a modulation on a bit stream constituting the codeword and outputting a symbol stream corresponding to the codeword; An interleaver for performing Orthogonal Frequency Division Multiplexing (OFDM) symbol-based interleaving on the output symbol stream to rearrange symbol sequences; A layer mapping module for dividing and rearranging the rearranged symbol streams into two or more layers in a predetermined order; And And a precoding module for performing precoding on a symbol stream mapped to the layers, Wherein the predetermined order is configured to be alternately mapped to the two or more layers in symbol units of a symbol stream corresponding to the codeword, Wherein the OFDM symbol based interleaving comprises interleaving symbols allocated to subcarriers in one OFDM symbol. 8. The method of claim 7, Wherein the two or more layers include a first layer and a second layer, Wherein the predetermined order is configured such that even-numbered symbols of the rearranged symbol stream are mapped to the first layer and odd-numbered symbols are mapped to the second layer. 8. The method of claim 7, If the number of the transmission blocks is two, the number of the code words is two, A symbol stream corresponding to a first codeword of the two codewords is divided into one layer and a symbol stream corresponding to a second codeword of the two codewords is divided into two layers according to the predetermined order to be mapped , Transmitter. 10. The method of claim 9, Even symbols of a symbol stream corresponding to the second codeword are allocated to a first one of the two layers, And odd-numbered symbols of a symbol stream corresponding to the second codeword are mapped to a second one of the two layers. 8. The method of claim 7, If the number of the transmission blocks is two, the number of the code words is two, A symbol stream corresponding to a first codeword of the two codewords is transmitted to a first layer and a second layer, and a symbol stream corresponding to a second codeword of the two codewords is transmitted to a third layer and a fourth layer, respectively And maps the divided signals in the predetermined order. 12. The method of claim 11, The even-numbered symbols of the symbol stream corresponding to the first codeword are mapped to the first layer and the odd-numbered symbols of the symbol stream corresponding to the first codeword are mapped to the second layer, The even-numbered symbols of the symbol stream corresponding to the second codeword are mapped to the third layer and the odd-numbered symbols of the symbol stream corresponding to the second codeword are mapped to the fourth layer. delete delete delete delete delete delete delete delete delete delete delete delete

Images