Precoder Design for MU-MISO Transmission with Guaranteed QoS Constraints

We study the problem of designing transmit beamformer for maximizing the weight sum rate of a multi-user (MU)-multiple-input single-output (MISO) interference broadcast channel (IBC) with individual quality-of-service (QoS) constraints. The considered problem is known to be nonconvex and NP-hard indeed, and most of existing high-performance solutions are based on the centralized method. In this paper, we propose a distributed approach for the weighted sum rate maximization (WSRM) problem with QoS constraints by combining successive convex approximation (SCA) framework and the alternating directions method of multipliers (ADMM) technique. More specifically, the proposed algorithm extends a current centralized solution, where the SCA is used to arrive at an approximate convex problem at each step of the iterative procedure. The idea is that we apply the ADMM technique to solve the convex problem of the SCA based subproblem in a distributed manner. We also discuss some heuristic ways to accelerate the convergence rate of the proposed algorithm. Numerical simulations are provided to compare different models for both centralized and distributed algorithms.