A low-complexity pilot contamination elimination method for channel estimation in massive MIMO systems

摘要

Pilot contamination is a major limitation in estimating the uplink channel state in massive MIMO systems using time division duplex communication method. This limitation has a huge impediment to harnessing the main advantages of massive MIMO systems such as spectral and energy efficiencies. In this article, a new low-complexity subspace-based method is proposed for eliminating pilot contamination and channel estimation, which exploits virtual channel modeling combined with a new problem formulation technique. On the contrary to most of the existing approaches in which the availability of correlation matrices of users and intercell data exchanges are needed, the proposed method eliminates the pilot contamination without need these confining assumptions. By employing the virtual beam searching technique and projection onto the component subspaces of virtual beams and pilot sequences, the proposed method estimates channel vectors of different cell users with very low computational complexity. Simulation results show that the proposed method achieves good performance with very low normalized mean square error and high achievable rates in the presence of severe pilot contamination and under different cell conditions.