QoS-Guaranteed Energy-Efficient Power Allocation in downlink multi-user MIMO-OFDM systems

Energy efficiency has currently become one of the central topics in today´s wireless communication industry. In this paper, we focus on the energy-efficient design in downlink multi-user MIMO-OFDM systems, so as to optimize the energy efficiency with users´ quality of service (QoS) guarantees. Particularly, an optimization problem concerning power allocation is formulated, where the objective is the energy efficiency measured by “Bit per Joule” and the constraints are users´ QoS demands. Based on a mathematical equivalence and Lagrange duality, we propose an effective algorithm, named QoS-Guaranteed Energy-Efficient Power Allocation, to address the problem and achieve the optimal energy efficiency. Simulation results reveal that our proposed algorithm brings about remarkable gains on energy efficiency and simultaneously satisfies users´ QoS requirements.