Optimization Scheme For Wireless Powered Cooperative Communication Transmission Strategy In Edge Networks

Wireless communication technology has developed rapidly in recent years and has penetrated into every aspect of daily life.In the future era of all things connected,massive wireless communication devices(such as wireless sensors,wearables,smartphones,etc.)work at the edge of the network at the same time,and there is a widespread energy limitation problem.The energy supply problem has become a key bottleneck restricting the development of future wireless communication technologies.To solve this problem,researchers has proposed energy transmission and energy harvesting technology with the basis of RF.In this way,wireless devices collect and store energy from signal sources such as base stations and wireless hotspots,so as to provide a continuous energy supply for wireless devices to ensure their normal operation.This thesis is aimed at wireless communication edge network scenarios,the RF energy transmission technology is used to solve the problem of equipment energy supply,and the relay cooperation technology is used to solve the problems of poor coverage of the edge network,blind spots,and poor communication quality.In this thesis,two technologies are combined to propose an efficient transmission technology,wireless energy-carrying cooperative communication technology.Specifically,this thesis considers a system model that includes a hybrid transmitter,multiple relays,and a receiver.In order to improve the efficiency of RF energy transmission,this thesis deeply studies the beamforming strategy of the transmitting antennas and the transmission strategy of the energy collection relays,and designs two relay energy collection strategies for the existence of the direct link,power splitting(PS)protocol and time switching(TS)protocol.In PS protocol,energy and information are sent simultaneously.In the TS protocol,energy and information are sent separately.In this paper,under two energy harvesting strategies,the beamforming strategy of the transmitter,the transmission strategy of the relays,and the energy harvesting strategy are jointly optimized.The thesis proposes optimization problems with the system throughput maximization as the goal and relay transmission power as the constraints.The introduction of wireless energy collaboration technology in the edge network can bring about throughput gains,but it also brings complex non-linear coupling relationships between multiple relays,which leads to the problem that the maximum throughput constructed is non-convex optimization.To solve this problem,the thesis propose a scaling scheme to obtain the lower bounds of performance for the TS and PS protocols.After scaling down the optimization problem of two protocols,the problems can be tackled by optimally solving a convex problem and monotonic optimization problem,respectively.The core contribution of this thesis is to establish a wireless energy-carrying cooperative communication model for the dense edge network scenario.Considering that the direct link always exists,the optimization problems of two receiving modes in PS and TS are constructed respectively.The corresponding solutions are given,and the simulation results are used to prove the feasibility of the research.