Research On Spatially Coupled LDPC Code Window Decoding Based On Multi-Object Symbols And Anti-Error Propagation

The diagonal bands of the Spatially Coupled Low-Density Parity-Check(SC-LDPC)code check matrix constructed on the basis of the protograph show the characteristics of nonzero terms.Compared with Belief Propagation(BP)of full matrix,window decoding brings lower complexity and timely delay,but the decoding performance is also reduced,and the complexity of window decoding still has a large space to decrease.Firstly,in order to further reduce the complexity of SC-LDPC code window decoding,multi-target symbol window decoding is proposed.The algorithm can greatly reduce the complexity by increasing the number of target symbol output and increasing the step size of window sliding after decoding of each window.However,if the number of target symbols output is too large,the decoding performance will be seriously damaged.Therefore dynamic multi-target symbol window decoding is proposed.The state of decoding process is judged by whether the decoding output of several consecutive windows meets the parity check,and then flexibly adjust the number of output target symbols of subsequent windows and the step size of subsequent window sliding according to the state.Simulation shows that the algorithm can reduce the complexity of decoding with almost no loss of decoding performance.Then on the basis of dynamic multi-target symbol decoding window join window iterative maximum adjustable mechanism,put forward dynamic multi-target symbols based on iterative maximum adjustable window decoding.Simulation results show that the algorithm can further reduce the decoding complexity.Secondly,SC-LDPC window decoding performance loss is related to error propagation.To combat error propagation,dynamic parameter tuning algorithm,message reuse algorithm are proposed.The dynamic parameter tuning algorithm increases the upper limit of subsequent window iteration or window size when it detects error output from several successive windows.Message reuse takes the external log-likelihood ratio(LLR)of the previous window instead of the output log-likelihood ratio(LLR)as the target symbol related information to the subsequent window.Simulation results show that compared with traditional window decoding,dynamic parameter tuning algorithm improves decoding performance at the expense of complexity,and message reuse algorithm improves complexity while reducing bit error rate.Furthermore,by integrating message reuse with multi-target symbol and dynamic multi-target symbol window decoding algorithms,SC-LDPC code window decoding optimization algorithm based on message reuse is proposed.Simulation results show that compared with the original algorithm,the SC-LDPC window decoding optimization algorithm based on message reuse can further improve the decoding performance and complexity.