Energy-efficient power allocation for multi-user MIMO systems with GZI precoding

To achieve the energy efficiency (EE) for multi-user multiple-input multiple-output (MU-MIMO) systems with GZI precoding, based on an actual power consumption model, the paper investigates the power allocation (PA) optimization problem with guaranteeing the sum rate for all downlink users and the different rate requirements for different downlink users. For the case of guaranteeing the sum rate for all downlink users, the highly complex optimization problem is firstly reformulated into an equivalent pseudo-convex form to be handled by the Lagrange Multiplier method. Then, it is simplified with reducing 2-dimension PA parameter into 1 dimension. Finally, the closed-form optimal solution is obtained through deriving of complex equations involving the log function. And for the case of guaranteeing the different rate requirements for different downlink users, the concrete numerical solution to the optimization problem is iteratively obtained through convex optimization toolbox in MATLAB. Simulation results validate the efficacy of the proposed optimization scheme. Furthermore, it is illustrated that the proposed optimization algorithm shows more optimal than average PA and antenna selection algorithms.