Mixed window decoding method and system of joint source channel arbitrary moment coding system

Abstract

The invention belongs to the technical field of decoding, discloses a mixed window decoding method of a joint source channel arbitrary moment coding system, and aims to reduce the decoding complexity of the system and maintain the error correction performance equivalent to that of the existing decoding scheme. The main method of the JHWD scheme is to implement a self-adaptive local extension window decoding strategy in a sliding window area, so that the complexity caused by global extension window decoding can be effectively reduced, and error propagation caused by sliding window decoding is reduced. The method provides a good decoding scheme for the JSCAC system in a low-complexity transmission scene. A low-complexity decoding scheme is provided for a joint source channel arbitrary moment coding system, and popularization of the system and application of the system in a low-complexity communication scene are facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of decoding, and in particular relates to a hybrid window decoding method and system for a joint source channel arbitrary time coding system. Background Art

[0002] Joint source channel coding (JSCC) is a coding technology that designs the coding of the source and channel in an interdependent manner and realizes the optimal communication system as a whole. JSCC technology can be used in any communication system that violates Shannon's separation coding theorem and needs to consider both the source and the channel, such as communication systems with limited power, bandwidth, complexity or delay, multi-user shared channel systems, and different types of communication environments composed of heterogeneous sources or channels.

[0003] There are several typical coding schemes for joint source channel coding technology. At the transmitter, the channel encoder can provide channel state information to the source encoder for bit allocation and source coding optimization. On the other hand, the source encoder can also provide auxiliary source side information for unequal error protection (UEP) during channel coding or modulation. At the receiver, both the a priori and a posteriori information of the source can be used for iterative decoding between the source decoder and the channel decoder, which is one of the most popular JSCC solutions.

[0004] In 2002, Fresia first proposed a JSCC system in the paper "Joint source channel coding" that uses two LDPC codes (abbreviated as D-LDPC) to complete source compression and channel error correction, and implements joint BP decoding within a global factor graph model framework that includes source and channel coding structures. Since then, many code types have been introduced into this JSCC system, such as block dual-protograph LDPC code (DP-LDPC), bipolar code (D-Polar), spatially coupled LDPC (SC-LDPC) code, and spatially coupled repetition accumulation code (SC-RA).

[0005] In the above solution, the present invention mainly focuses on a joint source-channel coding system at any time based on SC-RA codes (JSCAC). It is a JSCC encoding and decoding scheme that combines causal spatially coupled coding and extended window decoding, which can greatly improve the error correction performance of traditional JSCC systems and is more suitable for high-reliability and low-latency communication scenarios. However, the extended window decoding strategy of the JSCAC system has high decoding complexity and memory space requirements, which affect the practical application of the JSCAC system. In view of this, the present invention proposes a joint hybrid window decoding (JHWD) method, aiming to reduce the decoding complexity while maintaining error correction performance comparable to that of traditional extended window decoding.

[0006] Through the above analysis, the problems and defects existing in the prior art are as follows:

[0007] The extended window decoding strategy of the JSCAC system has high decoding complexity and memory space requirements, which affect the practical application of the JSCAC system. Summary of the Invention

[0008] In view of the problems existing in the prior art, the present invention provides a hybrid window decoding method for a joint source-channel coding system at any time.

[0009] The present invention is implemented as follows. A hybrid window decoding method for a joint source-channel coding system at any time includes:

[0010] S1. Initial extended window decoding stage:

[0011] The decoding delay t satisfies t = j, 1 <= j <= 3γ - 2. Use the source submatrix Channel submatrix And the prior log-likelihood information of the source Perform joint BP decoding on the first to jth information blocks, where H sc And H cc Represent the original source matrix and channel matrix, and the values separated by commas in the subscript brackets respectively represent the selected row and column ranges, and p represents the source probability; the maximum number of decoding iterations is imax1; after the decoding ends, update the source posterior log-likelihood information of the first to jth information blocks at time t - 1 with the decoding result at time t as:

[0012] S2. Sliding window decoding stage:

[0013] The decoding delay t satisfies t = j, 3γ - 2 < j <= T, where T is the maximum decoding delay;

[0014] S3. According to the source posterior log-likelihood information Make hard decisions and output decoding results.

[0015] Further, the sliding window decoding stage:

[0016] S2-1. Window sliding mode:

[0017] When j = 3γ-1, the decoding of the first information block is abandoned and the sliding window is at H sc and H cc In the example above, the window is shifted down by γ rows and right by 1 column; when j>3γ-1, the decoding of the j-3γ-2th information block is abandoned, and the sliding window is in H sc and H cc In the middle, move down 1 row and right 1 column;

[0018] S2-2, conventional decoding stage:

[0019] Using the source sub-matrix Channel Sub-Matrix And the initial likelihood information Z sc Perform joint BP decoding on the j-3γ+3~j information blocks, with a maximum number of iterations of imax1; after decoding, update the posterior log-likelihood information of the j-3γ+3~j information blocks as follows:

[0020] S2-3, Correction decoding stage:

[0021] Assume that the initial value of the companion sub-check flag is S_check = 1; when 1 <= k <= γ, if S_check = 1, then use the source sub-matrix Channel Sub-Matrix And the updated source posterior log-likelihood information Perform joint BP decoding on the j-3γ+3~j-γ+k information blocks; the maximum number of iterations is imax2, and the value of imax2 is smaller than imax1; after decoding, perform a companion check, if S_check=0, then end the local adaptive extended window decoding in the sliding window; after decoding, update the posterior log-likelihood information of the j-3γ+3~j-2γ+2 information blocks as follows:

[0022] Another object of the present invention is to provide a hybrid window decoding system of a joint source channel arbitrary time coding system, comprising:

[0023] Extended window decoding module, used in the initial extended window decoding stage:

[0024] Sliding window decoding module, used in the sliding window decoding stage:

[0025] The decoding result output module is used to make a hard decision based on the source posterior log-likelihood information and output the decoding result.

[0026] Another object of the present invention is to provide a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the mixed window decoding method of the joint source channel coding system at any time.

[0027] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to perform the steps of the mixed window decoding method of the joint source channel coding system at any time.

[0028] Another object of the present invention is to provide an information data processing terminal, which is used to implement a hybrid window decoding system of the joint source channel encoding system at any time.

[0029] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0030] The joint source channel coding system at any time is a type of coding system that has extremely high requirements for low delay and high reliability for industrial control and tracking systems. However, the complexity of the traditional joint source channel extended window decoding algorithm increases linearly with the increase of the length of the information sequence, which limits the application and promotion of the joint source channel coding system at any time. Considering that the information sequence in the low-delay and high-reliability scenario has the characteristic of limited coupling length, three strategies are mainly used to limit the linear growth of decoding complexity: 1) The starting point of the decoding window is movable; 2) The length of the decoding window does not change; 3) The extended window decoding within the sliding window is performed in an adaptive manner. The hybrid window decoding algorithm proposed in the present invention provides a low-complexity decoding scheme for the joint source channel coding system at any time while ensuring the decoding performance, solves the problems and bottlenecks of the system in terms of decoding complexity, and provides greater possibilities for the promotion of the system and its application in low-complexity communication scenarios.

[0031] Second, the technical solution of the present invention fills the technical gap in the industry at home and abroad: in order to ensure the transmission characteristics of the joint source channel at any time, that is, the decoding error rate decreases exponentially with the delay, the decoding algorithm must adopt the form of an extended window. Simple sliding window decoding will destroy the transmission characteristics at any time. The technical solution of the present invention allows the starting point of the traditional extended decoding window to be movable, and the window size is no longer increased indefinitely. Thereby retaining the transmission characteristics of any time unique to the extended window decoding, and limiting the linear increase in decoding complexity brought by the extended window decoding. Thereby filling the technical gap in the industry at home and abroad.

[0032] (2) Whether the technical solution of the present invention solves the technical problem that people have been eager to solve but have never succeeded in solving: the linearly increasing decoding complexity has always been the bottleneck problem faced by the joint source channel any-time coding system, and it is also the key factor that makes it difficult for the system to be put into practical application. The technical solution of the present invention effectively reduces the decoding complexity of the system while ensuring the decoding performance, making the industrial application of the joint source channel any-time coding system no longer out of reach.

[0033] (3) Whether the technical solution of the present invention overcomes technical bias: The industry has always believed that sliding window decoding cannot guarantee that the system has the transmission characteristics at any time; however, the technical solution of the present invention adaptively implements extended window decoding within the sliding window, so that the decoding performance still maintains the transmission characteristics at any time, thereby overcoming technical bias.

[0034] Third, the technical solution of the present invention solves the problems of low coding efficiency, high bit error rate and insufficient energy utilization in the source channel coding system in the prior art in industrial applications. By introducing the hybrid window decoding method, the present invention can jointly process the source and channel coding at any time, greatly improving the decoding accuracy and data transmission efficiency.

[0035] Specifically, the significant technical advances of the present invention include:

[0036] 1. Improve coding efficiency: By jointly processing the source sub-matrix and the channel sub-matrix in the initial extended window and sliding window decoding, the utilization of energy and information in the decoding process is optimized, and the coding efficiency in the data transmission process is significantly improved, which is particularly suitable for scenarios requiring low latency and efficient transmission.

[0037] 2. Reduce bit error rate: A decoding strategy based on posterior log-likelihood information is adopted, so that in a dynamic transmission environment, the system can adjust according to the real-time status of the received signal, effectively reducing the bit error rate in the decoding process and enhancing the reliability of the system.

[0038] 3. Adaptive adjustment of the decoding window: The sliding window mechanism of the present invention is combined with locally adaptive extended decoding, so that the system can flexibly adjust the size and position of the decoding window when facing different channel conditions, thereby effectively coping with sudden interference of the channel and further improving the robustness of the system.

[0039] 4. Enhanced application flexibility: The system can be widely used in communication networks, satellite transmission, the Internet of Things and other fields. Through its efficient encoding and decoding mechanism, it can significantly improve the quality and speed of information transmission in a variety of complex scenarios.

[0040] The present invention solves the bottleneck problem in the existing source channel coding system in practical industrial applications, achieves significant technical progress, and helps to improve the overall performance of modern communication systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a flow chart of a mixed window decoding method of a joint source channel encoding system at any time provided by an embodiment of the present invention.

[0042] Figure 2 It is a structural block diagram of a hybrid window decoding system of a joint source channel encoding system at any time provided by an embodiment of the present invention.

[0043] Figure 3 It is a hybrid window decoding structure diagram of a joint source channel arbitrary time coding (JSCAC) system provided by an embodiment of the present invention.

[0044] Figure 4 It is an asymptotic analysis diagram of the decoding complexity of the JSCAC system based on density evolution provided by an embodiment of the present invention.

[0045] Figure 5 It is an asymptotic analysis diagram based on density evolution of the characteristics of the JSCAC system at any time provided by an embodiment of the present invention.

[0046] Figure 6 It is a diagram of the error correction performance of any information block in a data link as the decoding delay changes, provided by an embodiment of the present invention.

[0047] Figure 7 It is a diagram of the overall bit error rate performance and decoding complexity of the data link when the decoding delay is t=100 provided by an embodiment of the present invention.

[0048] Figure 8 This is a diagram showing the influence of the length of the information block provided by the embodiment of the present invention on the bit error rate performance and decoding complexity of the data link. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] An embodiment of the present invention provides a joint source channel arbitrary time coding system, the system comprising:

[0051] A source coding module, used to perform source coding on input source information and output source coded information;

[0052] A channel coding module, used for performing channel coding on the information encoded by the source to generate encoded channel information;

[0053] A hybrid window decoding module includes an initial extended window decoding stage and a sliding window decoding stage, wherein the initial extended window decoding is used to perform joint BP decoding on the information block when the delay range is 1 to 3γ-2, and the sliding window decoding is used to perform joint BP decoding through a moving window when the delay range is 3γ-2 to T;

[0054] The hard decision module is used to make a hard decision based on the source posterior log-likelihood information and output the decoding result.

[0055] The mixed window decoding module further comprises:

[0056] The source a posteriori log-likelihood information updating module is used to update the source a posteriori log-likelihood information of the information block at the previous moment based on the result of the current decoding moment after the initial extended window decoding phase is completed.

[0057] The sliding window decoding module includes:

[0058] The window sliding control unit is used to control the sliding mode of the window in the source matrix and the channel matrix. When the delay reaches 3γ-1, the decoding of the first information block is abandoned, and the window is slid down by γ rows and moved right by one column; when the delay exceeds 3γ-1, j-3γ-2 information blocks are abandoned, and the window is moved down by one row and moved right by one column.

[0059] The sliding window decoding module further comprises:

[0060] The companion sub-check module is used to perform companion sub-check on the j-3γ+3 to j-γ+k information blocks in the modified decoding stage of the sliding window decoding, and decide whether to continue the decoding process of the local adaptive extended window according to the check result.

[0061] like Figure 1 As shown, a hybrid window decoding method for a joint source channel coding system at any time provided by an embodiment of the present invention includes the following steps:

[0062] S1. Initial extended window decoding stage:

[0063] The decoding delay t satisfies t = j, 1 <= j <= 3γ - 2, and the source sub - matrix channel sub - matrix and the prior log - likelihood information of the source are used to perform joint BP decoding on the 1st to jth information blocks, where γ is the coupling length, H sc and H cc represent the original source matrix and channel matrix, the values separated by commas in the subscript brackets respectively represent the selected row and column ranges, p represents the source probability; the maximum number of decoding iterations is imax1; after the decoding ends, the source posterior log - likelihood information of the 1st to jth information blocks at time t - 1 is updated with the decoding result at time t as:

[0064] S2. Sliding window decoding stage:

[0065] The decoding delay t satisfies t = j, 3γ - 2 < j <= T, where T is the maximum decoding delay;

[0066] S3. Perform hard decision according to the posterior log - likelihood information of the source and output the decoding result.

[0067] The sliding window decoding stage provided by the embodiment of the present invention:

[0068] S2 - 1. Sliding mode of the window:

[0069] When j = 3γ - 1, the decoding of the 1st information block is abandoned, and the sliding window moves down γ rows and right 1 column correspondingly in H sc and H cc ; when j > 3γ - 1, the decoding of the (j - 3γ - 2)th information block is abandoned, and the sliding window moves down 1 row and right 1 column correspondingly in H sc and H cc ;

[0070] S2 - 2. Conventional sliding window decoding stage:

[0071] Use the source sub - matrix channel sub - matrix and the initial likelihood information Z of the source sc to perform joint BP (Belief Propagation) decoding on the (j - 3γ + 3)th to jth information blocks, and the maximum number of iterations is imax1; after the decoding ends, the posterior log - likelihood information of the (j - 3γ + 3)th to jth information blocks is updated as:

[0072] S2 - 3. Adaptive local extended window decoding stage:

[0073] Assume that the initial value of the companion sub-check flag is S_check = 1; when 1 <= k <= γ, if S_check = 1, then use the source sub-matrix Channel Sub-Matrix And the updated source posterior log-likelihood information Perform joint BP decoding on the information blocks j-3γ+3 to j-γ+k; the maximum number of iterations is imax2, and the value of imax2 is smaller than that of imax1; after decoding, perform a companion check, and if the result of the companion check S_check=0, then end the local adaptive extended window decoding in the sliding window; after decoding, update the posterior log-likelihood information of the information blocks j-3γ+3 to j-2γ+2 as follows: The calculation formula of the companion check is as follows:

[0074]

[0075] in and They are the source decoding result and channel decoding result of the kth joint BP decoding result respectively. It is the source parity check matrix involved in the kth joint BP decoding.

[0076] S3, based on the source posterior log-likelihood information Make hard decisions and output decoding results.

[0077] like Figure 2 As shown, a hybrid window decoding system of a joint source channel coding system at any time provided by an embodiment of the present invention includes:

[0078] An extended window decoding module, used in the initial extended window decoding stage;

[0079] A sliding window decoding module, used in the sliding window decoding stage;

[0080] The decoding result output module is used to make a hard decision based on the source posterior log-likelihood information and output the decoding result.

[0081] Another object of the present invention is to provide a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the mixed window decoding method of the joint source channel coding system at any time.

[0082] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to execute the steps of the hybrid window decoding method of the joint source-channel coding system at any time.

[0083] Another object of the present invention is to provide an information data processing terminal for implementing the hybrid window decoding system of the joint source-channel coding system at any time.

[0084] Specific implementation of the present invention:

[0085] As Figure 3 shown in the decoding method, a low-complexity decoding scheme is provided for the joint source-channel coding system based on SC-RA code at any time.

[0086] The technical solution of the present invention is as follows:

[0087] A decoding method for an encoding and decoding system for SC-RA codes, where the encoding and decoding system is a joint source-channel coding system at any time. The suitable scenario for this method is that the chain length L and the coupling length γ satisfy L→∞ and L>γ. The size selection of the decoding window includes the coupling length interval where the information block to be decoded is located, and the two adjacent and forward coupling length intervals, with a total length range of 3γ-2 information blocks, which are respectively called the first coupling interval, the second coupling interval, and the third coupling interval. The decoding method includes the following steps:

[0088] S1. Initial extended window decoding stage: The decoding delay t satisfies t = j, 1 <= j <= 3γ-2

[0089] Use the source submatrix channel submatrix and the prior log-likelihood information of the source to perform joint BP decoding on the 1st to jth information blocks, where H sc and H cc represent the original source matrix and channel matrix, and the values separated by commas in the subscript brackets respectively represent the selected row and column ranges, and p represents the source probability; the maximum number of decoding iterations is imax1. After the decoding is completed, update the source posterior log-likelihood information of the 1st to jth information blocks at time t-1 with the decoding result at time t as:

[0090] S2. Sliding window decoding stage: The decoding delay t satisfies t = j, 3γ-2 < j <= T, where T is the maximum decoding delay

[0091] S2-1. Window sliding method: When j = 3γ-1, abandon the decoding of the 1st information block, and the sliding window is in H sc and Hcc In the example above, the window is shifted down by γ rows and right by 1 column; when j>3γ-1, the decoding of the j-3γ-2th information block is abandoned, and the sliding window is in H sc and H cc In the middle, move down 1 row and right 1 column;

[0092] S2-2, conventional sliding window decoding stage: using the source sub-matrix Channel Sub-Matrix

[0093]

[0094] And the initial likelihood information of the source Zsc Perform joint BP decoding on the j-3γ+3~j information blocks, with a maximum number of iterations of imax1. After decoding, update the posterior log-likelihood information of the j-3γ+3~j information blocks as follows:

[0095] S2-3, adaptive local extended window decoding stage: set the initial value of the companion sub-check flag to S_check = 1; when 1 <= k <= γ, if S_check = 1, use the source sub-matrix Channel Sub-Matrix And the updated source posterior log-likelihood information Perform joint BP decoding on the information blocks j-3γ+3 to j-γ+k; the maximum number of iterations is imax2, and the value of imax2 is smaller than imax1. After decoding, perform a companion check. If S_check = 0, the local adaptive extended window decoding in the sliding window is terminated. After decoding, update the posterior log-likelihood information of the information blocks j-3γ+3 to j-2γ+2 as follows:

[0096] S3, based on the source posterior log-likelihood information Make hard decisions and output decoding results

[0097] The hybrid window decoding algorithm proposed in the present invention is marked as (joint hybrid widow decoding, JHWD) in the implementation case description and the accompanying drawings, and the comparative cases are the joint expanding window decoding algorithm (joint expanding window decoding, JEWD) and the partial joint expanding window decoding algorithm (partial joint expanding window decoding, PJEWD) in the document "Joint Source Channel Anytime Coding". The numerical analysis method used in the implementation case is the density evolution asymptotic analysis method proposed in the document "Joint Source Channel Anytime Coding based on Spatially Coupled Repeat-Accumulate Codes" for analyzing the performance of the SC-RA based JSCAC system.

[0098] 1. Specific application fields or related products of the present invention.

[0099] The specific application field of the present invention is low-latency and high-reliability wireless communication systems, control systems, and decoders or output players in tracking systems. There are currently no related products on the market.

[0100] 2. Relevant evidence of the technical effects obtained by the embodiments of the present invention.

[0101] The parameter settings in the embodiment are as follows: the degrees of the source and channel variable nodes are Q sc =4 and Q cc =3; the degrees of the source and channel check nodes are A sc =12 and A cc =3; the exponential connection probabilities of the source and channel are λ sc = 0.5 and λ cc =0.1; the coupling lengths of the source and the channel are both set to γ=5; the maximum number of decoding iterations at each stage is set to i max1 =30,i max2 =5, the source probability is p=0.02, and the signal-to-noise ratio of the channel is 2dB.

[0102] Example:

[0103] This example uses numerical analysis and simulation to evaluate the decoding complexity and decoding performance of the JHWD algorithm proposed in the present invention. Figure 4 and Figure 5 is the result of numerical analysis, Figures 6 to 8 is the simulation result.

[0104] Figure 4 This is an asymptotic analysis of the decoding complexity of the JSCAC system based on density evolution. The figure compares the average number of information updates of the three decoding schemes as the decoding delay t changes. When the decoding delay t is small, the average number of information updates of the three schemes is small; as t increases, the average number of information updates of the three schemes shows an approximately linear growth. Figure 4 The right Y-axis shows the reduction ratio of the average number of information updates of the PJEWD decoding scheme and the JHWD decoding scheme proposed in the present invention relative to the traditional JEWD scheme. The reduction ratios of the two schemes increase rapidly in the smaller interval of t<600, and the growth rate tends to be flat after t>600. In the decoding delay interval of t=100-1000, the reduction ratio of the average number of information updates of PJEWD relative to JEWD increases from 26% to 48%, while the reduction ratio of the average number of information updates of the JHWD scheme proposed in the present invention relative to JEWD increases from 58% to 94%. That is, the decoding complexity of the JHWD scheme of the present invention is compared with that of the PJEWD scheme, and the reduction ratio of the average number of information updates is increased by about 2 times.

[0105] Figure 5 This is an asymptotic analysis of the arbitrary time characteristics of the three decoding schemes, that is, the characteristic that the error probability of any information block in the data link decreases with the decoding delay. Since any information block in the data link has the same arbitrary time decoding characteristics, in order to facilitate observation and analysis, the characteristic curves of adjacent information blocks of each scheme are displayed. Figure 5 It can be seen that under the same coupling length (γ=5), the decoding error rate curves of the JEWD and PJEWD schemes have similar decreasing speeds; while the decreasing speed of the error rate curve of the JHWD scheme proposed in the present invention is relatively slow, because the error rate decreasing speed of the JHWD scheme is related to the window size. When γ=5, the window length is 3γ-2=13. Figure 5 At the same time, the error rate curves of the JHWD scheme under different coupling lengths are shown. It can be seen that the larger the coupling length and the longer the window size, the smaller the slope of the error rate curve, that is, the slower the decline speed, but a lower decoding error probability can be obtained. Figure 5 As shown, the larger the coupling length, the higher the decoding complexity.

[0106] Figure 6 The variation of decoding error probability of any information block in the data link with decoding delay t is observed when the information block length is Ncc = 32 bits. Figure 6It can be seen that the bit error rate performance (BER) of any information block of the JSCC scheme based on D-LDPC in the document “Joint source channel coding” cannot be improved with the increase of decoding delay, so it is a straight line parallel to the horizontal axis. However, in the JSCAC system with a causal coupling structure, the BER performance of any information block has the opportunity to be further improved at the subsequent decoding delay moment. Among them, when γ=5, it is found that the BER curve of the JHWD scheme proposed in the present invention is located in the middle of the BER curves of the JEWD and PJEWD schemes, and the BER curve of the PJEWD scheme has the largest slope. The BER curves of the PJEWD and JEWD schemes reach a flat layer after t=10, while the JHWD scheme proposed in the present invention reaches the flat layer the latest (t=13, which is the window length), which is consistent with Figure 6 The numerical analysis results are consistent. Moreover, the error floor of the JHWD scheme proposed in the present invention is closer to that of the PJEWD scheme. When the coupling length increases to γ=8, although the slope of the BER curve of the JHWD scheme of the present invention is smaller than that when γ=5, it can obtain a lower error probability. At t=8, the BER value decreases to less than 10-6. This experiment shows that the decoding characteristics of the JHWD scheme proposed in the present invention at any time are between the JEWD scheme and the PJEWD scheme.

[0107] Figure 7 The overall BER performance and decoding complexity analysis of the data link were observed when the information block length was Ncc = 32 bits and t = 100. Figure 7 (a)), the JHWD scheme of the present invention shows a smaller curve slope than PJEWD and JEWD, and its performance is the worst at low signal-to-noise ratio stage, which is closer to the BER performance of the JEWD scheme; while at high signal-to-noise ratio stage greater than 1.5dB, the JHWD scheme can obtain a lower error floor than JEWD, and its BER performance is closer to that of the PJEWD scheme. In terms of decoding complexity, Figure 7(b) shows the normalized average number of information updates of the JHWD scheme and the PJEWD scheme relative to the JEWD scheme. The decoding complexity of the traditional JEWD scheme does not change with the change of the signal-to-noise ratio, so it is a parallel line. The decoding complexity of the JHWD scheme and the PJEWD scheme is reduced relative to the JEWD scheme, and it is more obvious in the high signal-to-noise ratio stage. When SNR = 3dB, the average number of information updates of the PJEWD scheme is reduced by about 26.47% compared with the JEWD scheme, while the average number of information updates of the JHWD scheme proposed in the present invention is reduced by about 69.61% compared with the JEWD scheme. This experiment shows that the JHWD scheme proposed in the present invention can reduce the decoding complexity to a considerable extent while maintaining a BER performance similar to that of the traditional JEWD scheme and the PJEWD scheme.

[0108] Figure 8 The influence of different information block lengths Ncc on the overall decoding performance and decoding complexity of the data link is observed under the same data link length. Figure 8 (b) It can be seen that the larger the information block length, the lower the decoding complexity of the JHWD scheme; Figure 8 As shown in (a), in terms of BER performance, increasing the block length does not lead to a continuous decline in BER performance. When the information block length Ncc is greater than 128 bits, the larger block length means that the data link does not get too many opportunities to repeat error correction in the low signal-to-noise ratio area, resulting in a decline in BER performance. When the signal-to-noise ratio is greater than 1.5dB, the better channel environment narrows the performance difference with the shorter block length scheme. On the other hand, under the same coupling length and window length conditions, the increase in the information block length will lead to an increase in the proportion of initial extended window decoding in the JHWD scheme, while the proportion of the sliding window decoding stage will decrease, thereby improving the BER performance of the JHWD scheme in the high signal-to-noise ratio area and even surpassing the shorter block length scheme. Therefore, under the premise of knowing the observed data link length, carefully selecting the length of the information block can obtain performance gains in both error correction performance and decoding complexity.

[0109] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. It can be understood by a person of ordinary skill in the art that the above-mentioned devices and methods can be implemented using computer executable instructions and / or contained in a processor control code, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. Such code is provided on the carrier medium. The device and its modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0110] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A hybrid window decoding method for a joint source channel arbitrary time coding system, characterized in that: It includes the following steps: S1. Initial extended window decoding stage: The decoding delay t satisfies t=j,1<=j<=3γ-2 using the source sub-matrix Channel Sub-Matrix And the prior log-likelihood information of the source Perform joint BP decoding on the 1st to jth information blocks, where H sc and H cc represents the original source matrix and channel matrix, the values ​​separated by commas in the subscript brackets represent the range of the selected rows and columns, and p represents the source probability; the maximum number of decoding iterations is imax1; after the decoding is completed, the decoding result at time t is used to update the source posterior log-likelihood information of the 1st to jth information blocks at time t-1: S2. Sliding window decoding stage: The decoding delay t satisfies t = j, where 3γ - 2 < j <= T, and T is the maximum decoding delay; S3, based on the source posterior log-likelihood information Make hard decisions and output decoding results.

2. The hybrid window decoding method of the joint source channel arbitrary time coding system as claimed in claim 1, characterized in that: The said sliding window decoding stage: S2-1. Sliding mode of the window: When j = 3γ-1, the decoding of the first information block is abandoned and the sliding window is at H sc and H cc In the example above, the window is shifted down by γ rows and right by 1 column; when j>3γ-1, the decoding of the j-3γ-2th information block is abandoned, and the sliding window is in H sc and H cc In the middle, move down 1 row and right 1 column; S2-2. Conventional decoding stage: Using the source sub-matrix Channel Sub-Matrix And the initial likelihood information of the source Zsc Perform joint BP decoding on the j-3γ+3~j information blocks, with a maximum number of iterations of imax1; after decoding, update the posterior log-likelihood information of the j-3γ+3~j information blocks as follows: S2-3. Modified decoding stage: Assume that the initial value of the companion sub-check flag is S_check = 1; when 1 <= k <= γ, if S_check = 1, then use the source sub-matrix Channel Sub-Matrix And the updated source posterior log-likelihood information Perform joint BP decoding on the j-3γ+3~j-γ+k information blocks; the maximum number of iterations is imax2, and the value of imax2 is smaller than imax1; after decoding, perform a companion check, if S_check=0, then end the local adaptive extended window decoding in the sliding window; after decoding, update the posterior log-likelihood information of the j-3γ+3~j-2γ+2 information blocks as follows:

3. A hybrid window decoding system for a joint source-channel any-time coding system implementing the decoding method according to any one of claims 1 to 2, characterized in that: It includes: A source coding module, which is used to perform source coding on the input source information and output the source-coded information; A channel coding module, which is used to perform channel coding on the source-coded information to generate the coded channel information; A hybrid window decoding module, which includes an initial extended window decoding stage and a sliding window decoding stage. The initial extended window decoding is used to perform joint BP decoding on the information block in the time delay range from 1 to 3γ - 2, and the sliding window decoding is used to perform joint BP decoding by moving the window in the time delay range from 3γ - 2 to T; A hard decision module, which is used to perform hard decision according to the source posterior log-likelihood information and output the decoding result.

4. The joint source channel arbitrary time coding system as claimed in claim 1, characterized in that: The said hybrid window decoding module further includes: A source posterior log-likelihood information update module, which is used to update the source posterior log-likelihood information of the information block at the previous moment based on the result at the current decoding moment after the initial extended window decoding stage ends.

5. The joint source channel arbitrary time coding system as claimed in claim 1, characterized in that: The said sliding window decoding module includes: A window sliding control unit, which is used to control the sliding mode of the window in the source matrix and the channel matrix. When the time delay reaches 3γ - 1, the decoding of the first information block is abandoned, and the window is slid down γ rows and right one column; when the time delay exceeds 3γ - 1, j - 3γ - 2 information blocks are abandoned, and the window is moved down one row and right one column.

6. The joint source channel arbitrary time coding system as claimed in claim 1, characterized in that: The said sliding window decoding module further includes: A syndrome check module, which is used to perform syndrome check on the information blocks from j - 3γ + 3 to j - γ + k in the modified decoding stage of the sliding window decoding, and decide whether to continue the decoding process of the locally adaptive extended window according to the check result.

7. A computer device, characterized in that: The said computer device includes a memory and a processor. When the computer program stored in the memory is executed by the processor, the processor executes the steps of the hybrid window decoding method of the joint source-channel encoding system at any time as described in any one of claims 1 - 2.

8. A computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the processor executes the steps of the hybrid window decoding method of the joint source-channel encoding system at any time as described in any one of claims 1 - 2.

9. An information data processing terminal, characterized in that: The said information data processing terminal is used to implement the hybrid window decoding system of the joint source-channel encoding system at any time as described in claim 3.

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