MIMO单载波分数阶傅里叶域均衡系统及最优阶次选择方法

Single-carrier frequency domain equalization (SC-FDE) is an effective technique to cope with multi-path fading in wireless transmission. Multi-input Multi-output (MIMO) can greatly improve the spectrum utilization. The combination of these two techniques is a hot research topic; and has become the uplink transmission scheme for the next generation wireless communication system. Whereas, while the channel is fast time-varying, the performance of the traditional MIMO SC-FDE system would degrade a lot because of the non-diagonalization of the frequency domain channel matrix. It would cause severe subchannel interference. In order 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 the frequency domain. In this paper, the selection algorithm of the optimal fractional Fourier transform order is introduced. 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 conventional MIMO SC-FDE system in fast time-varying channels.