协作通信系统中的一种高效分集传输技术

A Diversity Transmission Technique with High Performance in Cooperative Communications Systems

研究协作通信系统中结合空时分组码与频域均衡的传输方案,采用判决反馈与干扰抵消等算法对该方案进行优化.中继节点对发射信号进行空时分组编码后发送,接收机将收到的信号做快速傅里叶变换处理,再进行空间-频域的联合均衡,最后变换回时域判决,即可得到发送信息的估计结果.该方案可获取中继提供的协作分集增益,且频域处理复杂度很低.本文通过判决反馈和干扰抵消等信号处理手段降低均衡过程带来的信噪比损失,提高了该算法在协作通信信道下的传输性能,计算机仿真结果表明,当信噪比为12dB时,新算法可将原算法的误码率从10-2以上降低到10-3以下.

The transmission scheme of STBC combined with frequency domain equalization （FDE） was discussed in the cooperative communications system in this paper, and the decision feedback as well as interference cancellation techniques were employed to improve the performance of the scheme. STBC carried out in the relay nodes to obtain the transmission signal, then, spatial and FDE were executed to the received signal after the fast Fourier transform （FFT） at the receiver, and finally, the estimation of the transmitted information was obtained by hard decisions after inverse FFT operations. The transmission scheme can obtain the cooperative diversities supplied by the relay nodes, and the complexity of FDE is low, so a practical use can be achieved. This paper introduces a new algorithm with high performance by mainly using decision feedback as well as interference cancellation techniques to reduce the signal-to-noise ratio （SNR） loss during the FDE. Computer simulations show that the new scheme can effectively work, when the SNR is 12 dB, the new one can reduce the bit error rate from 10^-2 to 10^-3 in the cooperative communications system.