Performance Analysis of Precoding Based on Massive MIMO System

In order to improve the system performance, the authors consider a single-cell multiuser Massive MIMO downlink time-division duplex (TDD) system for the imperfect channel state information (CSI). For the zero-forcing (ZF) and the matched filtering (MF) precoding scheme, the authors propose a normalization algorithm: the vector normalization. Assume that the channel estimation is used to acquire CSI by using the uplink pilot sequence, and utilize the proposed algorithm to normalize the precoding matrix in the downlink; we derive the achievable sum rate of ZF and MF. Through the analysis and comparison of two precoding schemes' performance, the authors conclude that ZF is better than MF with vector normalization algorithm in the high SNR region; and MF is better than ZF in the low SNR region. Simulation results confirm the above conclusion.