大规模MIMO时分双工系统信道互易性研究

时分双工的大规模多输入多输出（MIMO）系统中，信道估计和互易性校准决定了系统能否有效利用信道互易性.为了分析信道估计对系统性能的影响，推导出信道估计的均方误差，并得出了单用户MIMO系统的上下行信道容量的闭合表达式.此外，为了减小在线校准的误差，根据互耦的性质提出了新的互耦干扰模型，并借助基站具有的功率控制以及协调功能，设计出了一种能够减轻互耦干扰的校准方案.仿真结果表明，该方案具有可行性.

Research on Channel Reciprocity of Massive MIMO Time Division Duplex System

In time division duplex massive multiple-input multiple-output (MIMO) systems, the channel estimation and reciprocity calibration determine whether the system can effectively utilize channel reciprocity. In order to analyze the effect of channel estimation on the system performance, the mean square error of channel estimation is deduced and the closed-form expression of uplink and downlink channel capacity in single-user MIMO system is obtained. To reduce the error of on-line calibration, a new mutual coupling interference model was proposed by using the property of mutual coupling. With the help of base station power control and coordination functions, a calibration scheme was designed to reduce the mutual coupling interference. Simulations verify the feasibility of this scheme.