Spectral efficiency of massive MIMO networks with pilot contamination and channel covariance matrix estimation

This study addresses spectral efficiencies (SEs) in a massive multiple-input multiple-output cellular network with pilot contamination. Both uplink and downlink SEs are investigated with practical channel state information. A downlink precoder minimising signal detection error and power leakage with considerations on spatial correlation has been derived. Also, a low-complexity covariance matrix estimation method has been proposed and compared with the existing estimation method in terms of normalised mean-squared error. It has been demonstrated via simulations that both uplink and downlink SEs using the proposed covariance matrix estimation method can grow with the number of antennas even with a relatively small number of pilot symbols.