快速生成QAM比特置信度软判决度量的算法  

Bit Confidence-Based Soft Decision Metric Generation for QAM

作　　者：赵晋[1] 张建秋[1] 

机构地区：[1]复旦大学电子工程系,上海200433

出　　处：《电子与信息学报》2009年第4期985-988,共4页Journal of Electronics & Information Technology

基　　金：上海市科委创新行动计划(077062001)资助课题

摘　　要：在现代通信系统中,为了保证高的信道解码增益,信道解码器均采用软输入技术。传统的软判决度量大多是基于最小欧氏距离准则生成,该文提出一种基于比特置信度快速生成QAM软判决度量的算法,通过将比特置信度引入到QAM软判决度量的计算中来减少计算的复杂性。相比基于最小欧氏距离的软判决度量生成算法,该文提出的方法在保证信道解码器性能的前提下,减少了生成软判决度量的运算量。应用于中国数字电视地面传输标准DTMB系统的仿真结果表明,该文提出的软判决度量生成算法虽然降低了计算量,但性能几乎没有任何损失,具有良好的性能和可实现性。In modern communication systems, a channel decoder usually employs the soft input to guarantee a high channel decoding gain. A new soft decision metric for QAM is presented in this paper. Unlike traditional soft decision metric based on minimum Euclidean distance, the proposed metric is based on the bit confidences. Compared to traditional soft decision metric, the one presented in this paper can guarantee the channel decoder performance with less computation complexity. The numerical results applying the proposed method to the DTMB system indicate that the proposed soft decision metric reduces the computation complexity without any performance degradation. These results also show that the proposed metric is a good alternative for soft decision generations.

关 键 词：数字电视 软判决 比特置信度 对数似然比 正交幅度调制 低密度校验码 

分 类 号：TN949.197[电子电信—信号与信息处理]