删余LDPC与OFDM联合编码调制算法

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。

Joint coded modulation algorithm with erasure LDPC and OFDM

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.