A Game-Theoretical and Spatial Approach to Mitigate Pilot Contamination in Crowded Massive MIMO Systems

This paper presents a novel approach to mitigate pilot contamination by enabling effective beamforming in crowded massive Multiple-Input-Multiple-Output (MIMO) systems operating in Time Division Duplex (TDD) mode. The main idea is to resolve angular overlaps among the signals that base stations receive from users in the wireless network. In this method, users randomly become active and try to access their corresponding base stations. Then, they periodically participate in a carefully designed game wherein only winners get to remain active. In this game, the probability of winning among a group of contenders is a direct function of having relatively higher transmission power, better channel conditions, and more correlated directions of arrival to the angles that the base stations estimate. We analytically prove that this game can guarantee the resolution of the so-called angular overlap, which enables effective beamforming and leads to pilot decontamination. We also support our statements through Monte Carlo simulations.