A coding transmission method for MIMO systems

Abstract

The present invention discloses a coding transmission method for MIMO system, which is applied to N t Transmitting antennas and N r SM-MIMO system model with n receiving antennas. For any time t, there are only n transmitters. a The present invention uses an arbitrary linear block code C[n,k] to protect information. The possible transmission signals of the activated antennas are taken from the constellation signal set χ. Considering the time-invariant delay scheme, the (t, i)th coding sub-block p t (i) At instant t+T i Considered as the input of the SM mapper, the parameter T i The bits in the buffer are used for SM mapping in a column-by-column manner. The SM mapper obtains the bit sequence matrix C t As input, x t =(x t,0 ,x t,1 ,...,x t,i ,...,x t,α‑1 ) as output. t,i Indicates P t The i-th column transmits the signal x t,i By P t The SM mapper uses P t and P t+1 The correlation between the two channels is determined, so that the subsequent receiver can explore these correlations to improve the decoding performance. The present invention has the advantages of flexible structure, ability to approach channel capacity, good performance, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communication and digital storage, and in particular to a coding transmission method for a MIMO system. Background Art

[0002] With the continuous development of wireless communication technology, improving the spectrum efficiency and reliability of radio communications is crucial. Channel coding is a key guarantee for reliable data transmission, error control, and reliable storage. Currently, almost all practical error-correcting codes are linear, and linear block codes are also widely used. LDPC codes offer excellent performance approaching the Shannon limit, low decoding complexity, parallel decoding, and detectability of decoding errors, making them a new research hotspot in channel coding theory. At low signal-to-noise ratios (SNRs), LDPC codes have a high bit error rate (BER). When the SNR increases to a certain value, the BER decreases significantly. This period of significant BER decline is called the waterfall region. At high SNRs, the BER remains low and does not change significantly. Further increasing the SNR will not bring any benefit. This period is called the error floor region.

[0003] Modern life continues to demand higher data rates and improved quality of service in wireless links. Multiple-input, multiple-output (MIMO) technology is a solution to this problem by transmitting multiple data streams from multiple antennas. It offers advantages such as reduced transmission and reception complexity and improved error performance. In 2012, researchers proposed bit-interleaved coded spatial modulation (BICSM), a spatial modulation method that effectively mitigates channel fading and antenna correlation. BICSM generally outperforms uncoded SM systems in actual bit error rate (BER) levels and offers significant performance improvements across all criteria. Subsequently, numerous studies have investigated SM-MIMO systems using arbitrary linear block codes, which offer significantly lower complexity. In 2016, delayed BICM (DBICM) was proposed. In DBICM, certain bits from multiple codewords are mapped onto a single symbol, creating correlations between codewords that can be exploited by the receiver to improve decoding performance. DBICM with linear block codes exhibits significant performance improvements over BICM in the waterfall region. Summary of the Invention

[0004] The purpose of the present invention is to address the above-mentioned defects in the prior art, and to provide a coding transmission method for MIMO systems by combining the advantages of the above-mentioned technologies. DBICM is applied to the SM-MIMO system of linear block code, referred to as DBICSM. This scheme has the advantage of flexible construction, can improve the coded spatial modulation performance, and show better performance improvement in the waterfall area.

[0005] The purpose of the present invention can be achieved by taking the following technical solutions:

[0006] A coding transmission method for MIMO system, which is applied to t Transmitting antennas and N r SM-MIMO system model with 100 receiving antennas, for any time t, N t There are only n transmitting antennas a The root transmitting antennas are activated for transmission, and the linear block code C[n,k] is used for information encoding, where n is the code length in the block code, k is the number of information code elements in the block code, and the constellation signal set χ is used as the signal to be transmitted by the transmitting antennas in the activated state. The cardinality of the constellation signal set χ is |χ| = 2 q , q is an integer greater than 0, and the total number of different combinations of activated antennas is It is a combination symbol, indicating that the number of bits required to select B numbers from A numbers is w, Indicates rounding down operation, using p = w + n a q bits are used to determine the transmission signal at each time t in the SM mapper. It is assumed that the code length n of the linear block code is an integer multiple of p, that is, n = pα, where α is an integer greater than 0. If this assumption is not met, the code word v t An appropriate number of zeros is padded at the end so that the code length n of the block code after the zero padding is an integer multiple of p. The code memory of DBICSM is set to m, 0<m<p, m is an integer greater than 0, and the total number of couplings of the delay module is L, 2≤L and L is an integer. The code transmission method includes the following steps:

[0007] S1. At time t, the information sequence u of length n is t After being encoded by a linear block code encoder ENC with a code rate of R=k / n, the output codeword v t ;

[0008] S2, then the interleaver π pairs the codeword v t Reorganize the information and parity bits to obtain an information sequence c of length n t ;

[0009] S3, the information sequence c obtained above t The subsequence of p blocks with length α is obtained by serial-to-parallel (S / P) converter, denoted as C t =(c t (0) ,c t (1) ,...,c t (i) ,...,c t (p-1) ), ct (i) Represents the i-th block subsequence, and then sends the subsequence into a rectangular buffer of p rows and α columns to form a matrix P t For SM mapping, P t The i-th row is represented by p t (i) =(p t (i) (0),p t (i) (1),...,p t (i) (j),...,p t (i) (α-1)), and p t (i) is called the (t, i)th coding sub-block, p t (i) (j) is called p t (i) For the jth column in , the steps for setting the rectangular buffer are as follows:

[0010] S31. At the initial time t=0, the sequence c0 is converted into a p-block subsequence through a serial-to-parallel (S / P) converter, denoted as C0=(c0 (0) ,c0 (1) ,...,c0 (p-1) ),

[0011] S311. Send the all-zero sequence to the first m rows of the p×α rectangular buffer. Using the all-zero sequence as the beginning of the matrix, during the decoding process, the value of k can be used to determine that the first m portions of the information sequence are zero, thereby ensuring high decoding accuracy for this portion, which also helps improve subsequent decoding rates.

[0012] S312, the first pm subsequences c0 of C0 (0) ,c0 (1) ,...,c0 (p-m-1) The remaining pm rows are fed into the rectangular buffer row by row to obtain the P0 matrix in the rectangular buffer. The first part of the matrix P0 is composed of a certain zero sequence, which helps to improve the decoding performance.

[0013] S32. At the next time t=t+1, the sequence c1 is converted into a p-block subsequence through a serial-to-parallel (S / P) converter, denoted as C1=(c1 (0) ,c1 (1) ,...,c1 (p-1) ), the remaining m subsequences c0 at time t = 0 (p-m) ,...,c0 (p-1)After the first m rows are fed into the rectangular buffer, step S312 is executed to obtain matrix P1 using a subsequence of C1. Matrices P0 and P1 in the two rectangular buffers are correlated through C0, which is considered a completed coupling. Due to the correlation between matrices P0 and P1, decoding performance is also affected. Improving the decoding accuracy of the preceding information sequence also improves the decoding accuracy of the following information sequence.

[0014] S33, for the remaining sequence c t Execute step S31 and step S32 until the set L couplings are completed;

[0015] S4, considering the time-invariant delay scheme, SM mapping P t Each column P t,i As the input sequence, P t,i Indicates P t The i-th column transmits the signal x t,i By P t The i-th column in is obtained, assuming that at instant t+T i , SM mapper for P t Perform the mapping operation to obtain the output sequence x t =(x t,0 ,x t,1 ,...,x t,α-1 ), where 0 = T0 ≤ T1 ≤ ... ≤ T i ≤...≤T p-1 ≤m, parameter T i Denotes the i-th delay, the SM mapper uses two matrices P t and P t+1 The correlation between them allows subsequent receivers to explore these correlations to improve decoding performance, achieving lower bit error rates and better performance results compared to existing methods.

[0016] Furthermore, the information sequence u t is a binary sequence or a multi-element sequence.

[0017] Furthermore, the linear block code encoder ENC is an arbitrary linear block code encoder.

[0018] Furthermore, u t When it is a binary sequence, the matrix P t is a binary matrix of any type; when u t When it is a sequence defined on a multivariate finite field, the matrix P t is a multivariate matrix of any type defined over a multivariate finite field.

[0019] The present invention has the following advantages and effects compared to the prior art:

[0020] 1. The present invention proposes a coding transmission method for MIMO systems, which has the advantages of flexible construction and can approach channel capacity.

[0021] 2. The coding transmission method for MIMO system proposed in the present invention can obtain a better waterfall area compared with the existing coding transmission method.

[0022] 3. The present invention proposes a coding transmission method for MIMO systems, which combines a delayed bit interleaving coding method with spatial modulation. Compared with existing coding transmission methods, the structure of the present invention is more diverse and flexible.

[0023] In summary, the present invention proposes a coding transmission method for MIMO systems, which has the advantages of low bit error rate, ability to approach channel capacity, and more flexible construction method. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 This is a system block diagram of a coding transmission method for a MIMO system disclosed in the present invention;

[0026] Figure 2 In the present invention, m=1, T0=…=T p-2 =0, T p-1 =1 DBICSM encoder block diagram;

[0027] Figure 3 is a schematic diagram of the performance of the coding transmission system in Example 1 of the present invention;

[0028] Figure 4 This is a performance diagram of the coding transmission system in Example 2 of the present invention. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0030] Example 1

[0031] In this embodiment, the GSM-MIMO system model size is set to Nt = 4 transmitting antennas and N r = 4 receiving antennas, number of active antennas n a = 2, code memory m = 1, total number of couplings L = 100; at any time t, the binary LDPC code C[5600,2800] is selected as the linear block code. The signal to be transmitted by the active transmitting antenna is taken from the 16QAM signal, so q = 4; the number of bits required for the active transmitting antenna is selected as w = 2; the SM mapper uses p = w + n a q = 10 bits is used to determine the transmission signal at each time t, so α = 560 is obtained. The coding transmission method of the present invention includes the following steps:

[0032] Step S1: The information sequence u at any time t t After passing through the LDPC encoder ENC with a code rate of R = k / n = 0.5, the output codeword v t ;

[0033] Step S2: Then the interleaver Π pairs the codeword v t Reorganize the information and parity bits to obtain an information sequence c of length 5600 t ;

[0034] Step S3: The information sequence c obtained above is t The 10 subsequences of length 560 are obtained by serial-to-parallel (S / P) converter, denoted as C t =(c t (0) ,c t (1) ,...,c t (i) ,...,c t (9) ), and then send these subsequences into a 10×560 rectangular buffer to form the matrix P t For SM mapping, the steps to set up the rectangular buffer are as follows:

[0035] At the initial time t=0, the sequence c0 is converted into 10 subsequences through a serial-to-parallel (S / P) converter, denoted as C0=(c0 (0) ,c0 (1) ,...,c0 (9) ), send the all-zero sequence into the first row of the 10×560 rectangular buffer, and the first 9 subsequences c0 of C0 (0) ,c0 (1) ,...,c0 (8) Send the remaining 9 rows of the rectangular buffer line by line to obtain the P0 matrix in the rectangular buffer;

[0036] At the next time t=t+1, the sequence c1 is converted into 10 subsequences through the serial-to-parallel (S / P) converter, which is recorded as C1=(c1 (0) ,c1 (1) ,...,c1 (9) ). Take the remaining subsequence c0 at time t=0 (9) Enter the first row of the rectangular buffer and put the first 9 subsequences c1 of C1 (0) ,c1 (1) ,...,c1 (8) The remaining 9 rows are fed into the rectangular buffer row by row to obtain the matrix P1. Therefore, the matrices P0 and P1 in the two rectangular buffers are correlated through C0, which is recorded as completing one coupling;

[0037] For all remaining sequences c t Execute the above steps until the set 100 couplings are completed;

[0038] Figure 3 The coding performance of the coding transmission method for the MIMO system in this embodiment is given. In order to compare the performance, Figure 3 The performance of the original BICSM under binary LDPC codes is also given. Figure 3 It can be seen from the figure that compared with the existing coding transmission method, there is a gain of about 0.6 dB. The coding transmission method for the MIMO system provided in this embodiment has better performance.

[0039] Example 2

[0040] In this embodiment, the SM-MIMO system model size is set to N t = 8 transmitting antennas and N r = 8 receiving antennas, number of active antennas n a = 1, encoding memory m = 1, total number of couplings L = 100; at any time t, the binary LDPC code C[5600,2800] is selected as the linear block code. The signal to be transmitted by the active transmitting antenna is taken from the 16QAM signal, so q = 4; the number of bits required for the active transmitting antenna is selected as w = 3; the SM mapper uses p = w + n a q = 7 bits is used to determine the transmission signal at each time t, so α = 800 is obtained. The coding transmission method of the present invention includes the following steps:

[0041] Step S1: The information sequence u at any time t t After passing through the LDPC encoder ENC with a code rate of R = k / n = 0.5, the output codeword v t ;

[0042] Step S2: Then the interleaver Π pairs the codeword v tReorganize the information and parity bits to obtain an information sequence c of length 5600 t ;

[0043] Step S3: The information sequence c obtained above is t The 7-block subsequence with a length of 800 is obtained by the serial-to-parallel (S / P) converter, which is denoted as C t =(c t (0) ,c t (1) ,...,c t (i) ,...,c t (6) ), and then send these subsequences into a 7×800 rectangular buffer to form the matrix P t For SM mapping, the steps to set up the rectangular buffer are as follows:

[0044] At the initial time t=0, the sequence c0 is converted into 7 subsequences through the serial-to-parallel (S / P) converter, denoted as C0=(c0 (0) ,c0 (1) ,...,c0 (6) ), send the all-zero sequence into the first row of the 7×800 rectangular buffer, and the first 6 subsequences c0 of C0 (0) ,c0 (1) ,...,c0 (5) Send the remaining 6 rows into the rectangular buffer row by row to obtain the P0 matrix in the rectangular buffer;

[0045] At the next time t=t+1, the sequence c1 is converted into 7 subsequences through the serial-to-parallel (S / P) converter, which is recorded as C1=(c1 (0) ,c1 (1) ,...,c1 (6) ). Take the remaining subsequence c0 at time t=0 (7) Enter the first row of the rectangular buffer and put the first 6 subsequences c1 of C1 (0) ,c1 (1) ,...,c1 (6) The remaining 6 rows are fed into the rectangular buffer row by row to obtain the matrix P1. Therefore, the matrices P0 and P1 in the two rectangular buffers are correlated through C0, which is recorded as completing one coupling;

[0046] For all remaining sequences c t Repeat the above steps until the set 100 couplings are completed.

[0047] Figure 4 The coding performance of the coding transmission method for the MIMO system in this embodiment is given. In order to compare the performance, Figure 4The performance of the original BICSM under binary LDPC codes is also given. Figure 4 It can be seen from the figure that compared with the original coding transmission method, there is a gain of about 0.6 dB. The coding transmission method for the MIMO system provided in this embodiment has better performance.

[0048] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A coding transmission method for MIMO system, applied to N t Transmitting antennas and N r SM-MIMO system model with 100 receiving antennas, for any time t, N t There are only n transmitting antennas a The root transmitting antennas are activated for transmission, and the information is encoded using a linear block code C[n,k], where n is the code length in the block code and k is the number of information symbols in the block code. The signals to be transmitted by the transmitting antennas in the activated state are taken from the constellation signal set χ, and the cardinality of the constellation signal set χ is |χ| = 2 q , q is an integer greater than 0, and the total number of different combinations of activated antennas is It is a combination symbol, indicating that the number of bits required to select B numbers from A numbers is w, Indicates the rounding down operation, p=w+n is used in the spatial modulation SM mapper a q bits are used to determine the transmission signal at each time t. Assume that the code length n of the linear block code is an integer multiple of p, that is, n = pα, where α is an integer greater than 0. If this assumption is not met, the code word v t The end is padded with an appropriate number of zeros so that the code length n of the block code after the zero padding is an integer multiple of p. The code memory of DBICSM is set to m, 0<m<p, m is an integer greater than 0, and the total number of couplings of the delay module is L, 2≤L and L is an integer, where Delayed bit interleaved coded modulation (DBICM) is applied to a linear block code SM-MIMO system to form delayed bit interleaved coded spatial modulation (DBICSM). The coding transmission method includes the following steps: S1, the information sequence u at time t t After being encoded by a linear block code encoder ENC with a code rate of R=k / n, the output codeword v t ; S2, interleaver π pairs of codewords v t Reorganize the information and parity bits to obtain an information sequence c of length n t ; S3, the information sequence c obtained above t The subsequence of p blocks with length α is obtained by serial-to-parallel S / P converter, denoted as C t =(c t (0) ,c t (1) ,...,c t (i) ,...,c t (p-1) ), c t (i) Represents the i-th block subsequence, and then sends the subsequence into a rectangular buffer of p rows and α columns to form a matrix P t For SM mapping, P t The i-th row is represented by p t (i) =(p t (i) (0),p t (i) (1),...,p t (i) (j),...,p t (i) (α-1)), and p t (i) is called the (t, i)th coding sub-block, p t (i) (j) is called p t (i) For the jth column in , the steps for setting the rectangular buffer are as follows: S31. At the initial time t=0, the sequence c0 is converted into a p-block subsequence through a serial-to-parallel S / P converter, denoted as C0=(c0 (0) ,c0 (1) ,...,c0 (p-1) ), S311, send the all-zero sequence into the first m rows of the p×α rectangular buffer; S312, the first pm subsequences c0 of C0 (0) ,c0 (1) ,...,c0 (p-m-1) Send it row by row into the remaining pm rows of the rectangular buffer to obtain the P0 matrix in the rectangular buffer; S32. At the next time t=t+1, the sequence c1 is converted into a p-block subsequence through a serial-to-parallel S / P converter, denoted as C1=(c1 (0) ,c1 (1) ,...,c1 (p-1) ), the remaining m subsequences c0 at time t = 0 (p-m) ,...,c0 (p-1) The first m rows are fed into the rectangular buffer, and step S312 is executed to obtain the matrix P1 using the subsequence of C1. The matrices P0 and P1 in the two rectangular buffers are correlated through C0, which is recorded as completing one coupling. S33, for the remaining sequence c t Execute step S31 and step S32 until the set L couplings are completed; S4, considering the time-invariant delay scheme, SM mapping P t Each column P t,i As the input sequence, P t,i Indicates P t The i-th column transmits the signal x t,i By P t The i-th column in is obtained, assuming that at instant t+T i , SM mapper for P t Perform the mapping operation to obtain the output sequence x t =(x t,0 ,x t,1 ,...,x t,α-1 ), where 0 = T0 ≤ T1 ≤ ... ≤ T i ≤...≤T p-1 ≤m, parameter T i represents the i-th delay.

2. The coding transmission method for a MIMO system according to claim 1, wherein: The information sequence u t is a binary sequence or a multi-element sequence.

3. The coding transmission method for a MIMO system according to claim 1, wherein: The linear block code encoder ENC is an arbitrary linear block code encoder.

4. The coding transmission method for a MIMO system according to claim 2, wherein: When u t When it is a binary sequence, the matrix P t is a binary matrix of any type; When u t When it is a sequence defined on a multivariate finite field, the matrix P t is a multivariate matrix of any type defined over a multivariate finite field.

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