Research Of Encode And Decode Algorithm Optimization And Application For Non-binary LDPC Codes

When digital information transmits over the wireless channel with time-varying characteristics,the receiving end can’t receive the correct information due to the impact of noise,which has a serious impact on people’s daily lives.The most practical communication systems are based on wireless communication,and therefore how to improve the communication quality of wireless communication is one of the most important problems to be solved.The channel coding technology(LDPC)with excellent performance of the error correction used in wireless communication systems,that is an effective measure to solve the problems of wireless communication quality.With the ever increasing development of communication technology,internet technology and user demand for high-quality multimedia services,the future of wireless communications technology must offer the capability of higher data transfer rates,higher capacity utilization and higher communication quality,therefore,the communication technology used in the future wireless communication must meet the requirements of high bandwidth efficiency and high reliability.At this point,non-binary LDPC codes compared with binary LDPC codes have more significant advantages,but theirs high encode and decode complexity hinder their practical application in practical communication system,therefore,research on encode and decode algorithm optimization,constructed codes with strong error correction performance,design of higher field coded modulation scheme and application for LDPC codes has important theoretical analysis and practical significance.Specifically,this dissertation mainly investigates the encode and decode algorithm optimization and application for non-binary LDPC,and made certain findings as follows:Firstly,an improved LDPC constructed algorithm based on EBF/PEG algorithm which can be encoded by the iterative encoding algorithm with liner operation complexity is proposed.The new algorithm lowered the encoding complexity through the improvement of encoding scheme and the structure of parity-check matrix,though the error correcting capability of irregular LDPC codes constructed by the proposed algorithm is basically identical with the codes constructed by the EBF/PEG algorithm,but the powerful advantage makes it be easily implemented by the hardware.Meanwhile,an algorithm for constructing non-binary QC-LDPC codes on the basis of masking and puncturing techniques in consideration of the shortage of algebraic construction algorithm and time-varying performance of wireless channels is proposed.This scheme can reduce the complexity of the hardware implementation,enhance the error correction performance of the LDPC codes constructed by structure algorithm based on masking technology,and improve the average effectiveness of the communication system by realizing a rate-compatible encoding based on puncturing technology.Then,based on the study of decoding algorithm for non-binary LDPC codes,an improved stochastic decoding algorithm was proposed,this algorithm not only has lower check nodes and interweave computational complexity,but also can further reduce variable node computational complexity,at the same time,because the stochastic decoders are only functional for q≤16,the algorithm conducts certain improvements,so that it can apply q>16 situation.Finally,in order to meet the demand of high-speed,high-reliability and high-throughput for next generation wireless communications,a new joint LDPC coding-network coding scheme is proposed applicable to cooperate communication system.This scheme makes use of linearity of LDPC and network coding,as well as soft input and soft output module,the complexity of encoding and decoding of system is decreased,good error correction performance can be obtained and channel capacity is raised.Meanwhile,in order to make the cooperative relay communication system get good tradeoff between effectiveness and reliability,a novel joint channel coding modulation-network coding integration design program was proposed,i.e.non-binary LDPC-BICM-network coding scheme.The scheme combined channel coding modulation technology with network coding technology in relay node,and taking into account the correlation of the sequence of source nodes,a joint iterative correlation decoding algorithm was used when decoding,to ensure the effectiveness of the system and improve the reliability of the system.The scheme proposed by dissertation can get better coding gain compared to no relay system and uncorrelated system,therefore the effectiveness of the scheme is verified.