带宽有效传输下多进制LDPC码的不等错误保护  

Unequal Error Protection Nonbinary LDPC Codes for Bandwidth Efficient Transmission

作　　者：刘冰[1] 高俊[1] 陶伟[1,2] 窦高奇[1] 

机构地区：[1]海军工程大学电子工程学院,武汉430033 [2]海军装备研究院,北京100073

出　　处：《信号处理》2011年第7期1088-1094,共7页Journal of Signal Processing

基　　金：国家高技术研究发展计划(863)(2009AAJ128;2010AA7010422);国家博士后科学基金(200902671)

摘　　要：针对频谱有效的多进制低密度奇偶校验(Lcw-Density Parity-Check,LDPC)码编码调制系统,本文提出了一种在带宽有效传输下的两级不等保护方案,两级不等错误保护分别来自码字特性和高阶调制,充分利用了码字变量节点的度和高阶调制中比特的不等可靠性。编码调制系统采用多进制LDPC码与高阶调制匹配结合,无需信息转换,针对不同误符号率和误比特率的需求,可在符号级和比特级提供不同可靠性达到不等错误保护的目的。仿真结果表明,在AWGN信道下,采用16QAM调制方式的性能优于16PSK调制方式,利用变量节点的度和高阶调制提供的信息,码字的误符号率和误比特率具有明显的不等错误保护区分度,对于重要的比特给予了较强的保护。A two-level unequal error protection scheme of nonbinary low-density parity-check（LDPC）codes for bandwidth-efficient coded modulation systems is proposed in order to allow bandwidth efficient transmissions.These two unequal error protection levels are originated from codeword characteristics and high order constellation,which make full use of different degrees of variable node and bit reliabilities of high order modulation.The information transformation is not needed if nonbinary LDPC code and high order modulation are matched in coded modulation systems.The systems can provide different reliabilities at symbol and bit levels to meet the requirement of symbol error rate and bit error rate for real-life system implementations.Simulation results show that the 16QAM modulation is always superior to the 16PSK modulation over an AWGN channel.The distinct unequal error protection is achieved considering the variable node degrees and high order modulation.The transmitted bits have different sensitivities to errors,and the important bits are protected strongly.

关 键 词：多进制低密度奇偶校验码 不等错误保护 带宽有效传输 编码调制 

分 类 号：TN911.22[电子电信—通信与信息系统]