Research On Performance Analysis And Energy Efficiency Optimization Of Massive MIMO Systems

With the mobile terminal devices increasing rapidly, wireless data traffic is showing explosive growth. Spectral efficiency and energy efficiency become two of most important metrics for the development of the next generation wireless communication systems. Inheriting the benefits of conventional MIMO systems, massive MIMO systems can significantly enhance both spectral efficiency and energy efficiency.These main advantages enable the massive MIMO systems to be a promising candidate for 5G wireless communication networks.Therefore, this dissertation studies the following three main aspects of massive MIMO systems:Firstly, we analyze the performance of 3D MIMO technology in multi-cell multi-user massive MIMO systems. First, by refining the area which users distribute in, we make contract with the transmission characteristic simulations of 3D MIMO and 2D MIMO technologies and find that the performances of 3D MIMO technology are different in different areas. Then, we provide the explanation for the diversity of the performances of 3D MIMO technology. Last, we propose a prioritization scheme to improve the system performance.Secondly, we concentrate on the energy efficiency of multi-user massive MIMO systems and investigate the antenna configuration design based on the optimal energy efficiency in uplink. First, we propose a comprehensive and reasonable energy consumption model of the system considering the effect of different detecting algorithms. Then,in order to make the system to reach the optimal energy efficiency, we need to jointly optimize the transmission rate and the base station antenna number, which has been demonstrated. Besides, we propose a searching method to obtain the optimal system energy efficiency. Last,our simulations show the method we proposed provides the same performance with the exhaustive algorithm but has a lower algorithm complexity.Thirdly, we concentrate on the energy efficiency of multi-user massive MIMO systems and investigate the system design based on the optimal energy efficiency in uplink. First, under the condition of a large number of users and limited base station antenna number in a cell, we demonstrate that choosing users with better channel condition can improve the optimal system energy efficiency. Besides, we propose a user selection schema to obtain the optimal system efficiency. Then, our simulations show the schema we proposed improves the system energy efficiency effectively. Last, combining with the previous research, we propose a system design scheme based on the optimal energy efficiency in uplink, which is a selection of base station antenna number and users in different scenarios.