大规模MIMO TDD系统信道互易性研究

Channel Reciprocity of Massive MIMO TDD System

信道互易性被认为是大规模MIMO TDD系统最重要的优势之一。然而,在实际系统中,上下行信道由于信道时变、干扰不对称、射频增益不对称等情况的存在,信道并不完全互易。为了有效利用互易性,提高系统性能,互易性补偿方法成为研究热点。鉴于此,研究时变、干扰不对称、射频增益不对称等引起的大规模MIMO TDD系统信道互易性损失的问题,分析信道预测、闭环补偿和干扰抑制、天线校正等信道互易性损失补偿方法,对比补偿方法存在的局限性和不足,并对进一步的研究提出了相关建议。

Channel reciprocity is usually regarded as one of the most important advantages of massive MIMO TDD systems.However,in practical system,uplink channel and downlink channel are not ideally reciprocal for the existence of such factors as time-varying channel,asymmetry interference,RF gain mismatch and etc.In the process of effectively utilizing the reciprocity and improving the system performance,the method for reciprocity compensation becomes research hotspot.In view of this,the channel reciprocity loss in massive MIMO TDD systems caused by time-varying,asymmetric interference,and RF gain asymmetry is discussed,the channel-reciprocity-loss compensation method for channel prediction,closed-loop compensation,interference suppression and antenna correction analyzed,and compared with the limitations and shortcomings of compensation method,some relevant suggestions for further research also proposed.