Trade-off Between Energy Efficiency And Spectral Efficiency In Uplink Of Massive MIMO Systems

Exponential growth in data traffic and ubiquitous access requirements have triggered a dramatic expansion of wireless communications network infrastructure.Massive multi-input multi-output(Massive MIMO)technology can improve the spectral efficiency of the system by installing a large number of antennas at the base station,which is one of the key technologies of future mobile communication.However,with the rapid upgrading of energy demand,mobile operators urgently need to reduce the energy consumption of the system while maintaining continuous capacity growth.In recent years,people pay more and more attention to green communication technology.Then,due to the installation of a large number of antennas in the base station of large-scale antenna system,the number of radio frequency(RF)chains corresponding to the antennas also increases,and the hardware circuit consumption of RF chains gradually becomes impossible to ignore in the total power consumption of the system,so the energy efficiency of the system can no longer be guaranteed.Based on the comprehensive energy consumption of the system model presented in this paper,using the common statistical methods in the communication system,the power allocation and antenna selection techniques and some mathematical methods,we have analyzed the system energy efficiency of uplink,the relationship between the spectral efficiency and error performance,thus optimizing the energy efficiency of large-scale antenna system.Under the structure of a single cell communication system,the energy efficiency of the system can be further improved by power allocation at the transmitter of the system.The changes of the number of users and the number of base station antennas will affect the spectral efficiency and energy efficiency of the system.When the number of users is constant,the number of base station side antennas with optimal energy efficiency can be allocated to the system.The change of the number of base station antennas will bring about the change of spectral efficiency,which makes it difficult to guarantee the spectral efficiency of the system.On the contrary,maximizing the spectral efficiency of the system will make the energy efficiency of the system unable to reach the optimal value.Here,we try to change the relationship between energy efficiency and spectral efficiency by increasing transmission rate.At the same time,after the base station gets Channel State Information(CSI)through pilot,the antenna selection technology is used to select a part of the antennas with better channel gain to improve the energy efficiency of the system.By these ideas,the simulation analysis was made on the energy efficiency of system in this paper,looking for the relationship among transmission power,the number of antennas,the number of users and the system energy efficiency,spectral efficiency,according to the simulation results,we can arrange appropriate solutions for communication scenarios of different conditions,while trading-off on energy efficiency and the spectral efficiency of wireless communication system.