Research On Belief Propagation Decoding For LDPC Codes

With the continuous development of society and the advancement of modern science and technology,communication has become an indispensable part of people's daily lives.In particular,the continuous and rapid development of mobile communications in recent years has brought great convenience to our lives.The ultimate goal of communication is to achieve effective transmission of information,however,due to the existence of various interferences in the wireless channel and the development of communication technologies,it is necessary to transmit information more quickly,easily,and accurately,this makes it difficult to implement the information in a concrete manner,thus giving The R&D personnel of communications technology has brought even more severe challenges.In order to find a coding scheme that adapts to the reliability of high-efficiency,high-reliability communication,from early cyclic codes,BCH codes,RS codes,convolutional codes,etc.,to turbo codes developed in recent years and to the LDPC codes(Low Density Parity-Check Codes)studied in this article.LDPC codes have quickly become a research hotspot with their excellent decoding performance and relatively low decoding complexity.LDPC codes are mainly divided into two types of decoding algorithms:BF decoding algorithm(Bit-Flipping)and BP decoding algorithm(Belief-Propagation).Among them,the complexity of BF decoding algorithm is low,but its decoding performance is also the worst,It can only meet the situation that the decoding accuracy is not very high or the hardware condition is limited.,In contrast,BP decoding algorithm,which The complexity is higher than the BF algorithm,but it has excellent decoding performance.The main content of this paper is as follows:This paper first introduces the characteristics,representation,construction methods and classification of LDPC codes,and summarizes the coding schemes.Then,the LDPC codes BF,BP,RBP(Residual Belief-Propagation),NW RBP(Node-wise RBP),and IVC RBP(Informed Variable-to-Check RBP)decoding algorithm ideas and flow were analyzed in detail.Then,based on the NWRBP algorithm,this paper proposes an improved NWRBP(ENWRBP,Enhanced NWRBP)decoding algorithm,which counts the number of updates of each variable node in the NWRBP decoding process,and if the NWRBP iterative decoding fails,then it will update the least number of variables The node's initialization value is set to O.Simulation results show that compared with NWRBP,the ENWRBP decoding algorithm reduces bit error rate(BER)and frame error rate(FER).At present,how to optimize and upgrade the LDPC code decoder,without increasing the decoding complexity and the decoding delay,further reducing the error frame rate is an urgent problem to be solved.Finally,based on this problem,combining the advantages and disadvantages of different BP decoding algorithms,and referring to the three elements of decoding delay,decoding complexity and error frame rate,a sequential serial confidence decoding scheme is proposed,and verified by simulation results.The correctness of the method and the possibility of practical application.