删余LDPC与OFDM联合编码调制算法  

Joint coded modulation algorithm with erasure LDPC and OFDM

作　　者：龙毅[1] 匡麟玲[1] 陆建华[1] 

机构地区：[1]清华大学电子工程系,北京100084

出　　处：《清华大学学报（自然科学版）》2009年第1期82-85,共4页Journal of Tsinghua University(Science and Technology)

基　　金：国家"九七三"基础研究项目(2007CB310600);国家自然科学基金资助项目(60525107);国家"八六三"高技术项目(2007AA01Z2b3)

摘　　要：为了降低正交频分复用(OFDM)系统中信道的时变导致的高误码平台,提出一种联合编码调制算法。该算法利用低密度校验码(LDPC)对删除信道的优良特性,将LDPC编码删余比特进行预编码,映射为零调制符号,辅助调制解调器减轻子载波间干扰(ICI)自干扰。仿真结果表明:与分离的编码调制相比,在相同传输速率条件下,该方法降低时变信道导致的LDPC误码平台达3个数量级以上。该联合编码调制算法可明显提高宽带无线通信系统在高速移动环境下的性能。An erasure-based joint coded-modulation scheme was developed to reduce the high error floor caused by time-variance of wireless channels in orthogonal frequency division multiplex （OFDM） systems. Since the low-density parity-check （LDPC） has excellent performance in the erasure channel, erased bits are introduced into the LDPC codes and mapped into the zero modulated symbols to enable the modem to reduce the inter-carrier interference. Simulations show that the LDPC error floor for time-variant channels is reduced three fold compared with the separate coded-modulation system. This joint coded modulation algorithm significantly improves the performance of broad-band wireless communication systems in high speed environments.

关 键 词：正交频分复用 联合编码调制 低密度校验码 子载波间干扰 

分 类 号：TN929.5[电子电信—通信与信息系统]