Downlink performance analysis with enhanced multiplexing gain in multi-cell large-scale MIMO under pilot contamination

Pilot contamination has become a main constraint for large-scale multi-input multi-output (MIMO) systems. In this paper, we consider a large-scale multi-cell MIMO where the number of users per cell K is proportional to that of base station antennas M. Both performances with and without pilot contamination are analyzed in a quantitative way with closed-form expressions. Unlike some existing works, we derive the result by coping with the fast fading explicitly, which makes our result far more accurate for moderate to large antenna numbers. From our derived results, it is found that the interference still exists when both M and K tend to infinity with a fixed ratio, and larger K/M results in a smaller performance degradation due to the pilot contamination in the multi-cell large-scale MIMO.