ON PILOT CONTAMINATION IN MASSIVE MULTIPLE-INPUT MULTIPLE OUTPUT SYSTEM WITH LEAST SQUARE METHOD AND ZERO FORCING RECEIVER

Massive Multiple-Input Multiple-Output (MIMO) wireless communications refers to use of large number of antennas at transmitter and receiver to enhance spectral and energy efficiency. However, its performance is limited by a problem known as pilot contamination. In this paper, we present a comprehensive overview of massive MIMO system and studied degradation in performance due to pilot contamination. To showcase such effects, we have implemented the channel estimation using Least Square (LS) method with random pilots and time shifted pilot scheme through simulations. In this study we have used zero forcing (ZF) receivers. We have also studied performance improvement in presence of pilot using MMSE receiver. Further improvement is achieved in this work by introducing precoding technique for massive MIMO systems.