Enhancing uplink/downlink performance of massive MIMO system using time-shifted pilot signal transmission with pilot hopping

Abstract

In Massive Multiple Input Multiple Output (MIMO) system, pilot signals are reused to accommodate exponential rise in user density. This contaminates the channel estimation for the intended user and affects the system performance. In the proposed Time-Shifted Pilot signal Transmission with Pilot Hopping (TSPTPH) system, pilot signal transmission is overlapped with downlink data transmission and pilot signal hopping is performed in each coherence interval. Hopping is achieved by switching user to a new pilot signal, this results in random change in interfering users. This changes the large-scale fading coefficient β, which is a function of radial distance between base station and user and thus improves the system performance. Proposed system enhances the uplink and downlink signal to interference plus noise ratio and data rate by estimating the channel with minimum mean square error estimation and reduces the uplink signal to noise ratio for data transmission for normalised spectral efficiency with rising number of antennas at the base station.