Joint User Scheduling, Power Allocation, and Precoding Design for Massive MIMO Systems: A Principal Component Analysis Approach

Ahstract-This paper considers massive multiple-input multiple-output (MIMO) downlink system with imperfect channel state information at transmitter (CSIT). A new optimization framework for the joint user-scheduling, power control, and precoding design is presented. The key idea of the proposed optimization framework is to equivalently reformulate an sum-spectral efficiency maximization problem into the maximization problem of the product of Rayleigh quotients. Although this reformulated optimization problem is not convex, the sub-optimal solution that guarantees the first-order optimality condition is found using the proposed general power iteration algorithm. One major observation is that the proposed sub-optimal solutions provide significant gains in terms of the sum-spectral efficiency compared to the conventional user-scheduling algorithm conjunction with zero-forcing precoding for the massive MIMO systems.