MIMO单载波分数阶傅里叶域均衡系统及最优阶次选择方法

摘要

单载波频域均衡（SC-FDE）技术可以有效地克服无线传输中的多径衰落，而多输入多输出（MIMO）能大大提高频谱利用率。两者的结合已成为下一代无线通信系统上行链路的传输方案。然而，当无线信道是快速时变时， MIMO SC-FDE系统的频域信道矩阵将为非对角矩阵，形成严重的频域子信道间干扰，使系统性能急剧下降。针对这一问题，本文采用在分数阶傅里叶域均衡代替传统频域均衡，提出MIMO单载波分数阶傅里叶域均衡（MIMO SC-FrFDE ）系统。通过选择合适的分数阶傅里叶变换阶次，实现分数阶傅里叶域信道矩阵的近似对角化。仿真结果表明，在快速时变信道下，本文提出的MIMO SC-FrFDE系统比传统MIMO SC-FDE具有更好的误码率性能。%Single-carrier frequency domain equalization (SC-FDE) is an effective technique to cope with multi-path fading . Multi-input Multi-output (MIMO) can greatly improve the spectrum utilization .The combination of these two techniques has be-come the uplink transmission scheme for the next generation wireless communication .Whereas ,the performance of MIMO SC-FDE system would degrade a lot under fast time-varying channels because of severe subchannel interference .To solve this problem ,we propose the MIMO single-carrier fractional Fourier domain equalization system (MIMO SC-FrFDE ) .The equalization is done in the fractional Fourier domain instead of Fourier domain .Through selecting the optimal fractional Fourier transform order ,the fractional Fourier domain channel matrix can be approximately diagonalized .Simulation results show that our proposed system can improve the performance compared with the MIMO SC-FDE system in fast time-varying channels .