符号交织串行级联CPM系统优化设计

针对符号交织串行级联CPM系统中外码性能越好,接收端迭代译码后系统性能反而越差问题,研究了一种新型的符号交织串行级联CPM方案,该方案结合符号交织和比特交织的特点,在译码时延几乎不变前提下,对每一符号帧映射前的比特信息序列进行比特置换优化.相比符号交织串行级联CPM方案,采用本文所提的优化方案,能加快接收端译码迭代收敛速度,同时外码的性能也可直接影响到符号交织串行级联CPM系统的性能.

Optimization for Symbol-Interleaving Serially Concatenated CPM System

In a serially concatenated CPM system with symbol-interleaving,there is a phenomenon that the system with better outer codes,otherwise,its iterative decoding system performance was worse. To mitigate this phenomenon,a novel symbol-interleaved SCCPM was investigated,which combined the features of the symbol-wise and bit-wise interleaving,the sequence of information bits per symbol was permutated optimization before mapped to a symbol. Compared symbol-wise interleaved SCCPM scheme,using the mentioned permutated optimization schemes,it can speed up the convergence rate of iterative decoding,while the performance of the outer code may also directly affect the symbol interleaving SCCPM system performance with ignored decoding delay.