置信传播译码算法的性能测度

本文基于树和有限状态机系统地推导了低密度校验码(LDPC)置信传播译码算法中的消息修正公式,引入了连续消息空间的概率测度,推导了常见二元对称信道输出分布和迭代过程中消息密度进化的计算公式,讨论了算法性能的参数化估计.这种计算分析工具可以用于独立于信道的算法收敛性分析,有助于设计LDPC码,有助于分析LDPC码译码器的量化效应并实现快速译码方案,使其获得在实时通信系统中的应用.

Measure on the Performance of Belief Propagation Decoding Algorithm

Formulas for updated rules of the belief propagation algorithm applied to low density parity check (LDPC) codes are systematically derived based on the tree and the finite state machine (FSM).The probability measure on the continuous message space is introduced to evaluate the evolution of message densities within iterative decoding rounds,and derivations of the output distributions of common binary symmetric channels and the message density evolution are given in detail.The parameterized estimation of the performance of the algorithm is also discussed.The analytic and calculable means can be used to make systematical analysis for the convergence of BP algorithms independent of channels,and can be of help in designing LDPC codes and analyzing quantization effects for the fast decoding on the purpose of practical applications of LDPC codes to real time communication systems.