多阶段决策方法用于6∶8优化映射等重调制码的设计  

Design of 6∶8 Optimal-mapping Constant Weight Modulation Code by Multistage Decision Method

作　　者：陈端荣[1] 谢长生[2] 裴先登[2] 肖卫军[2] 

机构地区：[1]湖北大学数学与计算机科学学院,武汉430062 [2]华中科技大学计算机科学与技术学院,武汉430074

出　　处：《计算机学报》2005年第2期220-226,共7页Chinese Journal of Computers

基　　金：国家"九七三"重点基础研究发展规划项目基金(1999033006)资助.

摘　　要：6∶8等重调制码是全息存储记录通道中的一种有效通道码.然而,各种各样的噪声源和符号间串扰极易使检测到的一个等重码字与原等重码字相比发生一个0与1之间的2 码元交换错误事件(2 BREE).对于 6∶8 二进制顺序映射等重调制码(NCWMC)而言,由此导致在一个6比特数据字中平均产生约3比特误码.作者借助多阶段决策方法和贪心算法,设计出一种6∶8优化映射等重调制码(OCWMC).6∶8 OCWMC与6∶8 NCWMC相比,一个2 BREE所致的平均误比特数下降了0.5844比特.文章以 4∶6 OCWMC的设计为例,详细介绍了其设计过程.误码性能的仿真实验结果表明:6∶8 OCWMC比6∶8 NCWMC更适宜应用于具有严重的符号间串扰和噪声的全息存储记录通道.The 6:8 constant weight modulation code (CWMC) is an effective channel code for the holographic storage channel. However, because of various noise source and inter-symbol interference (ISI), one 2-bit reversing error event (2-BREE) between the two digits of a 1 and a 0 is easy to occur in a detected codeword compared with an original modulation codeword, which causes about a 3-bit error on the average in a 6-bit dataword for the 6:8 natural binary order mapping constant weight modulation code (NCWMC). Therefore, a 6:8 optimal mapping constant weight modulation code (OCWMC) is designed by the multistage decision method and the greedy algorithm. Compared with the 6:8 NCWMC, the average bit-error number for one 2-BREE of the 6:8 OCWMC can be reduced 0.5884 bits. As an example, the authors introduce the design of the 4:6 OCWMC in detail. Simulation results for the bit-error rate performance show that the 6:8 OCWMC is more adapted for the holographic storage channel with severe ISI and noise.

关 键 词：全息存储 等重调制码 多阶段决策 贪心法 符号间串扰 

分 类 号：TP333[自动化与计算机技术—计算机系统结构]