Performance analysis and comparison of ZF and MRT based downlink massive MIMO systems

In this paper the performances of zero-forcing (ZF) and maximum ratio transmission (MRT) are analyzed and compared in a downlink massive multiple-input multiple-output system. The system employs a large number of base station antennas serving multiple user terminals within the same cell. The achievable sum rate and the required downlink transmit power using each of the precoding schemes are derived, analyzed and compared under the same conditions and assumptions. Simulation results are found to coincide with the theoretical results, and show that ZF performs better than MRT under the same conditions.