Energy Efficient Optimization For Massive MIMO Systems Powered By Wireless Power Transfer

With the rapid development of new generation information technology,energy consumption is increasing,and green communication has become the trend of the times.Therefore,5G's key technology,massive multiple-input multiple-output(MIMO)technology emerged.Massive MIMO technology concentrates energy into narrow spatial regions through multiple antennas,reducing interference to surrounding users.Multiantenna at the base station improves the diversity gain,enhances the system robustness,increases the spatial freedom,reduces the user's transmit power,and achieves the dual goals of energy efficiency(EE)and spectral efficiency(SE).At the same time,the increasing popularity of smart devices is increasing the rate of wireless communications.Wireless power transfer(WPT)technology can collect green energy to transmit energy to wireless communication devices,improve the service life of wireless devices which are difficult to charge or replace batteries,and use multiple antenna arrays based on WPT.It can reduce the energy consumption of the system.Therefore,combining wireless energy transmission with massive MIMO systems complies with the development trend of green communication while improving the stability of wireless communication.This paper mainly studies the energy efficiency optimization of large-scale MIMO systems under wireless energy transmission conditions,and draws the following conclusions.First,aiming at the massive MIMO systems powered by WPT,an efficient resource allocation algorithm with energy efficiency maximization as the optimization target and joint transmit power,power allocation and wireless power transfer time allocation is proposed.The algorithm has better convergence,and compared with the throughput maximization algorithm and the guaranteed QoS minimum transmit power algorithm,it guarantees the user service quality and achieves the maximization of system energy efficiency and achieve higher throughput and lower total power consumption.The algorithm can effectively improve the energy efficiency of massive MIMO systems based on wireless energy transmission,and achieve a compromise between energy efficiency and spectral efficiency.Second,for massive MIMO systems with hardware impairments(HWIs)powered by WPT,combined with total transmit power,power allocation and time allocation,a large-scale MIMO energy efficiency optimal algorithm with HWIs under WPT conditions is proposed.Based on the optimal EE,the algorithm proves that HWIs can not neglect the large-scale MIMO system under WPT conditions.When the power of the power beacon is low,the impact of hardware damage on the system is small,and the power beacon is small.When the transmit power is high,hardware damage has a large impact on the system.This conclusion applies to the setting of the power beacon transmission power in practical applications.