On linear detector's spectral capacity for massive MIMO systems

Abstract

In this paper, we investigate and study the performance of three linear receivers in Multi-User Multiple-Input-Multiple-Output (MU MIMO) systems with large antenna arrays, namely very large MU MIMO or massive MIMO. In general, when the number of antennas at the Base Station (BS) is much larger than the number of users in the system, linear receivers perform quite well. Therefore, we present the derivation, with perfect Channel State Information (CSI) and imperfect CSI, the lower capacity bounds for Maximum-Ratio Combining (MRC), Zero Forcing (ZF) and Minimum Mean Square Error (MMSE) receivers. Mathematical analysis and simulations suggest that the users' transmission power can be reduced by the number of BS antennas in the case of perfect CSI, and can be reduced by the square root of the number of BS antennas in the case of imperfect CSI, while providing a set, desired Quality-of-Service (QoS). Compared to the single antenna system, the presented results showed that spectral efficiency of the system is enhanced by using fairly large antenna arrays.