Research On LDPC-RS Concatenated Code Technology In Wireless Communication System

In wireless communication,Low Density Parity Check(LDPC)codes and RS(ReedSolomon)codes can effectively improve the reliability of the communication system.Especially for LDPC codes,thanks to the sparsity of the check matrix(H matrix)and the application of soft decision decoding,its decoding performance has the characteristics of approaching the Shannon limit.However,due to the short cycle of the H matrix,LDPC will encounter code error floor after passing through the waterfall zone in the decoding stage,which reduces its reliability.Considering that RS codes can not only correct burst errors,but also eliminate the code error floor of LDPC codes,this paper proposes a LDPC-RS code concatenation scheme.In this scheme,RS is used as the outer code and LDPC is used as the inner code.Eliminate the code error floor problem of LDPC codes and improve decoding performance at the same time.In addition,based on the analysis and improvement of LDPC and RS soft decision decoding methods,this paper proposes a novel MNRA-BP(Modified Node Wise Residual Adaptive-Belief Propagation)joint iterative decoder,which has been successfully applied to LDPC-RS level Joint program.The simulation results show that the joint iterative decoder proposed in this paper solves the problem of LDPC code error floor,and at the same time reduces the complexity of decoding calculation while ensuring excellent decoding performance,which shows great application in wireless communication.prospect.The specific work and innovations of this article are as follows:(1)This article summarizes the basic principles and characteristics of channel coding and LDPC,including their construction methods and coding and decoding principles,and introduces the BP(Belief Propagation)algorithm of LDPC codes in detail,and the BP algorithm based on the log-likelihood ratio(LLR-BP),and an improved algorithm based on the minimum sum,etc.(2)Aiming at the LDPC decoding method,the belief propagation decoding algorithm based on the scheduling strategy is specifically analyzed.According to the analysis results,this paper studies three decoding improvement algorithms.First,this paper studies two new options for offset factor and normalization factor,and applies them to OMS(Offset-Min-sum)algorithm and NMS(Normalized-Min-sum)algorithm to reduce decoding While the complexity,the decoding performance is almost unchanged.In addition,this paper combines the traditional dynamic scheduling strategy NW-RBP(Node Wise-Residual Belief Propagation)algorithm with the minimum sum decoding algorithm,and proposes an improved NW-RBP algorithm,which reduces the decoding performance while ensuring the decoding performance.the complexity.(3)Based on the improvement of the above-mentioned LDPC decoding algorithm,this paper proposes a MNRA-BP joint iterative decoder,in which the LDPC code MNWRBP decoder and the RS code simplified ABP(Adaptive-Belief Propagation)decoder cascade,used in LDPC-RS cascade scheme.The simulation results show that the cascading solution solves the problem of LDPC code error floor.While ensuring good decoding gain of the cascaded code,it greatly reduces the complexity of cascaded decoding,which has a wide range of application prospects in wireless communication.