RATE ANALYSIS IN MASSIVE MIMO UNDER COVARIANCE ESTIMATION

Abstract

Massive MIMO is one of the enablers of the fifth generation. We study the performance of uplink massive MIMO system where the users suffer from the pilot contamination but possess linearly independent covariance matrices. Based on the latest results of the unlimited capacity of massive MIMO system with pilot contamination existence and assuming the covariance matrices are known, we show that this unlimited capacity result holds true for massive MIMO systems even when the covariance matrices are fully unknown (and not estimated) at the base station. However, covariance estimation improves the uplink capacity. We prove this result for both of static and time-varying channel models. We also consider both of single-cell and multi-cell massive MIMO systems with covariance estimation and semi-blind channel estimation for the two-antenna users. We show that the capacity is still unlimited by using MMSE channel estimation and data detection for all the scenarios mentioned above.