A Temporal Domain Based Method against Pilot Contamination for Multi-cell Massive MIMO Systems

Massive multiple-input and multiple-output (MIMO) systems have draw a lot of attention, due to its outstanding performance in energy saving and spectrum efficiency [1]. In massive MIMO systems, the intra-cell interference, uncorrelated noise and fast fading nearly vanish. Further study reveals that for multi-cell massive MIMO systems the performance will be limited by so-called pilot contamination (inter-cell interference) [2], where the transmitted CSI at one BS includes the channel coefficients from all the users using the same pilot. However, the analysis in [2] ignores a fact that the spatial/temporal characters of channel coefficients of different users are different such that they are distinguishable in certain extends. In practice, utterly isolating the user channels is extremely hard or even not feasible in certain cases. This paper firstly presents a practical temporal domain based method against pilot contamination without coordination, which just remains the strongest channel impulse responses (CIR) as the effective channel information. Simulation results show the outperformance of the proposed method with low complexity.