Research On Energy Efficiency Resource Management Optimization Algorithm For Massive MIMO-OFDMA System

MIMO(multiple Input multiple Output)system can make full use of the spatial freedom to improve the channel capacity and reliability of the system,and greatly improve the energy efficiency and spectral efficiency of the system by deploying a large array of antennas at the base station side.Therefore,it is considered as one of the key technologies in the fifth generation mobile communication system.With the rapid increase of energy consumption of wireless communication equipment and the high attention to environmental problems,green communication has become a consensus and the focus of resource allocation has gradually shifted from the pursuit of spectrum efficiency to achieving higher energy efficiency.In Massive MIMO OFDMA downlink system,the problems of energy efficiency optimization based on user association and power allocation have been widely studied.In this paper,we mainly focused on the energy efficient resource allocation algorithm based on user fairness in Massive MIMO OFDMA downlink system and user association algorithm based on user fairness in Massive MIMO heterogeneous networks.The main contributions of this dissertation are listed as follows.?The energy efficient resource allocation algorithm based on user fairness in Massive MIMO OFDMA downlink system was studied.This paper derived the capacity lower bound by using Zero Forcing(ZF)precoding with perfect CSI at base station.Based on user fairness,we proposed the energy efficiency utility model.In order to ensure the minimum transmission rate requirements of each user,a mathematical formulation of optimization issue was provided with the objective of maximizing system energy efficiency utility by adjusting the bandwidth,power and the number of antenna arrays at BS.We proposed a low complexity suboptimal algorithm to reduce the computational complexity of solving global optimal solution.The optimization process was divided into two steps.We first developed a bandwidth allocation algorithm by maximizing system energy efficiency utility.Then the number of antenna arrays at BS and the power allocation were jointly optimized to maximize the energy efficiency utility under bandwidth allocation algorithm.Finally,the performances of the user fairness and system energy efficiency were analyzed by simulation to verify the validity of the proposed algorithm.?The user association algorithm based on user fairness in Massive MIMO heterogeneous networks.We established the mathematical formulation of optimization issue with the objective of maximizing system energy efficiency utility.Since the optimization issue is a NP hard issue,it is difficult to obtain the global optimal solution.Therefore,we proposed a low complexity user association algorithm based on one to many matching game and proved the convergence and stability of proposed algorithm.Through the simulation of the performance of the proposed algorithm,it can achieve the tradeoff between energy efficiency and user fairness.