LDPC-COFDM系统在多径衰落信道下的性能分析

将正交频分复用(OFDM)技术应用于多径衰落信道下的高速数据传输是一个极富吸引力的方案,包括卷积码、RS码、Turbo码在内的多种纠错编码都曾被应用在OFDM系统中.最近,一种新的编码方案--低密度奇偶校验码(LDPC)引起了人们的注意.LDPC具有低的解码复杂度和逼近香农限的性能.文中仿真分析了LDPC-COFDM(编码正交频分复用)系统的性能,并与Turbo码系统进行了对比,结果表明该系统在多径衰落信道下显示出更为优越的性能.

The Performance of LDPC-COFDM Systems in a Multipath Fading Environment

Orthogonal Frequency Division Multiplexing(OFDM) is a very attractive technique for high-bit-rate data transmission in a multipath fading environment. Many error-correcting codes have been applied to OFDM such as convolutional codes,Reed-Solomon codes,Turbo codes,and so on. Recently,low-density parity-check (LDPC) codes have attracted much attention,particularly in the field of coding theory. Its performance is very close to that of the Shannon limit but with low decoding complexity like that of Turbo codes. We propose a LDPC coded OFDM (LDPC-COFDM) system to improve the bit error rate (BER) of OFDM. We show that the BER of the LDPC-COFDM is better than that of the TCOFDM on a multipath fading channel.