On The Cooperative Relay Wireless Network Combined With Energy Harvesting Technology

With the application of cooperative relay technology in wireless communication systems,the information transmission rate and the coverage area of base stations have been greatly improved.However,the conventional cooperative relay network has a limited working life,and in order to maintain the continuous operation of the network,it is necessary to periodically replace and recharge the battery at the relay.This is not only costly but also inconvenient for the practical operation.Therefore,obtaining energy from natural resources,such as solar energy,has been researched by many scholars,to extend the service life of wireless communication systems.However,there are a large number of uncontrollable factors of the natural resources,e.g.,weather conditions etc.,which make reliable communications difficult to be done.The traditional cooperative relay network often adopts the half-duplex relaying technique due to the simplicity of the system design.However,half-duplex technique will cause serious low spectral efficiency.Therefore,many scholars consider to utilize the combination of wireless energy harvesting technology,full-duplex technology and cooperative relay network technology to improve the spectrum efficiency and extend the operation life of the wireless transmission system.Firstly,this paper studies the full-duplex amplify-and-forward relay system which is based on power splitting energy harvesting protocol.For the three-node amplify-and-forward relay system,this paper proposes three different antenna selection schemes and analyzes the system ergodic capacity for the three antenna selection schemes,separately.Furthermore,this paper analyzes the optimal power allocation factor in the power splitting energy harvesting protocol and proposes an antenna selection scheme strategy based on statistical channel state information.Due to the full-duplex and wireless energy harvesting technology,the system performance of the wireless network becomes difficult to analyze.Therefore,a full-duplex decode-and-forward relay system combined with discrete energy states is studied in this paper.In order to improve the performance of power splitting energy harvesting relay system,a new full-duplex energy harvesting wireless transmission protocol was proposed.After the relay battery energy is discretized,the outage probability and ergodic capacity as well as the system performance under infinite relay battery capacity of the considered system are analyzed.All derivation results have been verified by the Monte Carlo simulation method.The research results show that self-interference has a great influence on system performance in a full-duplex power splitting energy harvesting relay system.Moreover,with different transmit powers,each of the three antenna selection schemes has their own superiorities.In a full-duplex decoding-and-forwarding relay system with discrete energy states,we find that increasing the degree of the battery capacity discretization can improve the system performance efficiently.The system performance will reach the theoretical ceiling when the relay battery capacity tends to be infinite.Nevertheless,we can also find that the optimal power allocation factor decreases with the increase of the transmit power and the optimal relay transmit power is closely related to the source transmit power.