Research And Design Of Rate Compatible Multivariate LDPC Codes

In the past 20 years,error correction coding technology has developed rapidly.At the end of the 20 th century,the discovery of Mackey et al.ushered in the research boom of low-density parity-check(LDPC)codes.Afterwards,it was discovered that compared with binary LDPC codes and Turbo codes with similar code length and code rate,Non-Binary Low-Density ParityCheck(NB-LDPC)codes have a greater gain in decoding performance in the case of short and medium codes.NB-LDPC codes are better than traditional binary LDPC codes in the case of short and medium codes,and are closer to the Shannon limit,so NB-LDPC codes has also become a research topic worthy of attention in the communication field.In adaptive coding modulation,rate-compatible codes are often used to increase or decrease the code rate.In terms of non-binary rate-compatible low-density parity-check(NBRC-LDPC)codes,a novel bit puncturing algorithm is proposed.The concept of binary mapping is applied to the non-binary parity-check matrix,and a set of bit-wise nodes are punctured according to the degree of variable nodes,resulting in NB-RC-LDPC codes with the higher rate code embedded in the lower one.Simulation results show that gains of 0.2-0.4dB are obtained in terms of the symbol error ratio(SER)compared with the symbol-wise performance.Based on the influence of cycle on LDPC decoding performance,combined with the minimum cycle detection algorithm,this paper proposes a symbol-level puncturing algorithm based on non-binary cycle.The minimum cycle detection algorithm calculates the minimum where each non-binary variable node is located.The cycle are classified,and the set with the largest cycle is selected for puncturing to increase the code rate.The simulation result proves that compared with the algorithms based on small cycle node puncturing and traditional symbol-wise puncturing,the symbol error rate performance of this scheme has more or less gain in each code rate,and the performance is good.Combining the concept of binary image,a bit-wise puncturing algorithm based on non-binary cycle is proposed.The symbol variable nodes of the large cycle are selected by the cycle detection algorithm,and the bit-wise according to the concept of binary image.The degree distribution of the bit variable node selects the better node for puncturing the target code rate.The simulation results prove that,compared with the symbol-wise puncturing algorithm based on the cycle,the bit-wise puncturing algorithm has a certain improvement in the performance of each bit rate.