Large system analysis for densification of cellular networks with massive MIMO

Abstract

In this paper, we investigate the impact of massive MIMO and distributed precoding on the performance of densified cellular networks via large system analysis. Based on the fact that the network rate performance of the cellular networks is scale invariant with reduced cell size, we want to find out if the interference of large scale dense cellular networks can be alleviated by the use of large scale antennas. We first derive the deterministic approximation of the users' SINR based on random matrix theory and show that the sum rate grows logarithmically with the number of transmit antennas in the base stations and the sum rate saturates quickly when the SNR increases even with very large number of antennas. To overcome the performance ceiling, a large system analysis of precoding with local channel state information under the framework of virtual signal to interference plus noise ratio (VSINR) is presented. The asymptotic results show that the VSINR precoding is also interference limited in high SNR. While as a special case, the limiting VSINR precoding can make the sum rate grow linearly with SNR in dB. We conclude that by combining large scale antennas and distributed precoding, we can efficiently tap the potential of large scale dense cellular networks without much network coordination.