Energy Optimization Method In EH Wireless Relay System

Energy harvesting(EH)technology has become a feasible solution to solve the energy supply problem of wireless relay systems.Each device in the communication system can maintain its own operation by collecting the available energy scattered in its surrounding environment.However,due to the low conversion efficiency of energy harvesting,the energy collected by a energy collecting equipment is very limited,all of which easily lead to the problem of energy shortage at the energy collection equipment in wireless relay systems.The number of nodes linked to the relay system is increasing,and the energy consumption is also increasing.In addition,with the development of the Internet of Things,relay cooperation between nodes has become very common,so the energy optimization problem related to relay systems has become research hotspot.Considering the problem of energy optimization in wireless relay systems,this dissertation mainly studies the problems between spectral-energy efficiency and interference-energy efficiency.On these two basic issues,a more in-depth study was carried out in combination with the working mode of wireless relay.First,an energy efficiency measurement criterion is proposed based on the renewable energy supply technology in the wireless relay system,and then based on this energy efficiency measurement criterion and Shannon's theorem,combined with the energy consumption of each node in the network and the rate between two consecutive hop links,under the condition that the energy of the relay node is limited,an energy optimization scheme for the relay selection of the wireless relay system based on the multi-relay model is proposed,and the system outage probability and energy efficiency formula is obtained.Monte Carlo simulation proves that the system outage probability obtained by the relay selection scheme proposed in this dissertation is lower than that obtained by other relay selection schemes,and gradually decreases as the average signal-to-noise ratio increases.Second,under the condition of energy limitation,the energy optimization problem in the two-way wireless relay system with the lowest rate is studied.In a two-way relay system,the signals in two directions that interfere with each other will couple at the relay,so that the energy efficiency function of the resulting system shows non-convex characteristics,so that it cannot be solved by traditional convex optimization methods.The variable method converts the obtained non-convex energy efficiency objective function into two sub-problems,namely convex optimization and concave-convex fractional programming problem,and then solved step by step,so as to obtain the optimal system energy efficiency.The results prove that when the system rate are different,the energy efficiency of the system proposed by this method is higher than that of the pure power optimization algorithm,and its gain is as high as 100% to 200%,and the energy efficiency of the system is basically asymmetric with the rate demand No department.The work of this dissertation improves the overall energy efficiency of the wireless relay system to a certain extent,lays the foundation for follow-up in-depth research.This dissertation has 26 figures,3 tables and 99 references.