一种码率自适应信源信道联合编码系统

A Rate-compatible Joint Source and Channel Coding System

双LDPC码系统是新近出现的一种信源信道联合编码系统,该系统的性能虽然好但不稳定,在信源熵增加时会产生很高的误码平台。为了解决这一问题,提出了一种码率自适应双LDPC码系统,此系统采用码率自适应LDPC码作为信源码,当信源熵变化时可以灵活地调整信源码率,从而保证系统在高低不同的信源熵情况下都具有优秀、稳定的性能。仿真结果显示,在高低不同的信源熵情况下,所提出的码率自适应双LDPC码系统性能均好于传统双LDPC码系统,而且在误比特率为10-6时都没有出现误码平台。

Double LDPC （ DLDPC ） code systems which have been proposed recently are a class of joint source and channel coding systems. The performance of a DLDPC code system is good but not stable, and especially a high error floor arises when the source entropy increases. In this paper, a rate-compatible DLDPC （ RC-DLDPC） code system is proposed to solve the problem. The RC-DLDPC code system work-ing with a rate-compatible LDPC code as its source code can flexibly change its source rate when the source entropy changes, so as to achieve excellent and stable performances under different source entro-pies. Simulation results show that under different source entropies, the proposed RC-DLDPC code systems outperform the traditional DLDPC code systems without any error floors at BER=10-6 .