Mitigation of sounding pilot contamination in massive MIMO systems

In massive multiple-input multiple-out (M-MIMO) systems, conventional sounding schemes may suffer from pilot contamination of cell edge users or a lowered number of serviced users in a multi-cell scenario. In this paper, we propose a partial sounding resource reuse (PSRR) method which aims to seamlessly guarantee the quality of service (QoS) of mobile users by mitigating the pilot contamination as well as minimize the reduction in the number of serviced users. To this end, the PSRR divides each cell area into center and edge areas, and partially reuses sounding resources among users in neighboring edge areas. We use a Markov chain model to analyze the performance of the PSRR. Then we evaluate the accuracy of our analysis through simulations, and show that the PSRR considerably improves QoS performance over the conventional schemes.