Optimized pilot power allocation for heterogeneous users in massive MIMO downlinks

This paper addresses the problem of pilot power allocation between users in massive multiuser multiple-input-multiple-output (MU-MIMO) systems with heterogeneous users. By exploiting the fact that heterogeneous users can experience different path loss and shadowing degradations due to their distinct locations, this paper proposes an optimized pilot power allocation strategy for massive MIMO systems with heterogeneous users in order to maximize the achievable sum rate. In this proposed technique, we exploit the Lagrange multiplier method to achieve an optimal solution to the pilot power allocation problem of heterogeneous users. Numerical results show that our proposed pilot power allocation scheme achieves significant performance gains compared with the conventional equal pilot power allocation one.