瑞利衰落信道下基于LDPC码USTM的MIMO系统

研究了一种联合低密度校验(LDPC,Low-Density Parity-Check)码和酉空时调制(USTM,Unitary Space-Time Modulation)技术在不相关瑞利平坦衰落(Rayleigh flat fading)下的多输入多输出信道(MIMO,Multiple-Input Multiple-Output)系统的性能.在无信道状态信息下,采用可并行操作的和积译码算法(SPA,Sum-Product Algorithm)的LDPCC-USTM级联系统具有优异的性能,并分析了不同LDPC码集下对系统性能的影响.仿真结果表明LDPCC-USTM级联系统比与未级联的相比有近23dB的编码增益,与基于Turbo码的USTM6]系统相比有5dB多的编码增益,且基于非规则的LDPC码的级联系统比基于规则码有近1dB的编码增益.

LDPC-coded based Unitary Space-Time Modulation MIMO system

A combined LDPC coded USTM scheme over uncorrelated Rayleigh flat fading channel and the combined iterative decoding algorithm are presented. Since USTM can work with no channel state information at either transmitter or receiver and LDPC code is proved an excellent channel code of which full parallel iterative decoding algorithm is employed, our proposed system can perform very well under no channel state information. The LDPC decoder performs sum-product iterative decoding algorithm conditioned on received space time symbols which is output of USTM demodulator. Both of regular-LDPC code and irregular-LDPC code applied are studied. The simulation results show that our proposed scheme provides almost 23 dB coding gain compared to uncoded USTM system, and 5dB more coding gain than Turbo coded USTM schemet61. And MIMO system based on irregular LDPC codes always outperforms about ldB coding gain than that based on regular LDPC codes.