Pilot reuse with a large number of antennas: Performance analysis and pilot contamination reduction

The performance of massive multiple-input multiple-output (MIMO) systems is heavily affected by pilot contamination. This paper considers the problem of pilot contamination in massive MIMO systems, and investigates the normalized mean square error (NMSE) of the minimum mean square error (MMSE) channel estimation algorithm in the presence of pilot contamination. An effective uplink training strategy with silent cell is proposed by carefully designing a sophisticated uplink training. Unlike many existing pilot contamination reduction schemes, the proposed scheme does not rely on the assumption of each base station needs to know the second-order statistics of either desired channels or interfering user channels. Simulation results are provided to confirm the excellent performance of this strategy.