Channel Covariance Matrix-Based Pilot Assignment for Massive MIMO Systems

In this letter, we propose a simple pilot assignment scheme for the massive MIMO systems with spatially-correlated channels. The proposed scheme, which is designed based on the average channel gains and the covariance matrices of the channels, effectively mitigates the pilot contamination and improves the sum spectral efficiency of the users. Moreover, the proposed scheme converges very fast and the convergence is achieved within few iterations. The simulation results show that the proposed scheme outperforms the existing pilot assignment schemes in terms of the spectral efficiency and the convergence speed.