基于非正则LDPC编码的OFDM高阶调制系统  

On the Performance of Irregular LDPC Coded OFDM Multi-Band Modulation System

作　　者：胡锦涛[1] 王永生[1] 周奋[1] 

机构地区：[1]西北工业大学电子信息学院,陕西西安710072

出　　处：《西北工业大学学报》2007年第3期446-450,共5页Journal of Northwestern Polytechnical University

摘　　要：为了改善OFDM系统的误码性能,研究了具有良好度分布的非正则LDPC码的生成算法,提出了一种基于非正则LDPC编码的OFDM高阶调制系统。仿真结果表明了基于非正则LDPC编码OFDM高阶调制系统具有良好的误比特率和误帧率特性。和无编码OFDM系统相比,非正则LDPC编码的OFDM系统采用QPSK及16-QAM调制时,在AWGN信道下,当误比特率(BER)为1-0 5时,分别节约7 dB和2.4 dB左右的信噪比;在R ay leigh衰落信道下,当BER为1-0 2时,分别节约9 dB和5 dB左右的信噪比。To satisfy the increasing demand of wireless communications, a low density parity check （LDPC） coded orthogonal frequency division multiplexing （OFDM） system was proposed in this paper. The progressive edge-growth arithmetic （PEG arithmetic） for irregular LDPC code was improved, which made it possible to construct LDPC codes with any degree distribution sequences. The decoding algorithm of LDPC-OFDM system under multi-band modulation was given. The simulation results show that, compared with uncoded OFDM system, the irregular LDPC coded OFDM system gains about 7 dB and 2.4 dB in AWGN channels with QPSK and 16-QAM at BER=10^-5 respectively, and gains about 9 dB and 5 dB in Rayleigh fading channels with QPSK and 16-QAM at BER= 10^-2 respectively.

关 键 词：正交频分复用 LDPC码 LDPC-OFDM系统 PEG算法 

分 类 号：TN911.7[电子电信—通信与信息系统]