Research On Wireless Relay Network Performance Based On Energy Harvesting

Wireless Sensor Networks(WSN)are mainly used in military equipment,medical care,infrastructure detection,emergency rescue,disaster relief and other works.Since the storage capacity of wireless sensor carrying power supply equipment is limited by volume,it can only provide limited energy for sensor nodes,so the network's life is rough to get a guarantee,and the randomness of position massive sensor nodes also brings great difficulty to replace the power supply equipments.Therefore,the research on the continuous energy supply of wireless sensor nodes is particularly meaningful.Based on the Energy Harvesting(EH)technology,the paper studies the continuous energy supply of WSN.By harvesting the energy of radio frequency signals in the external environment,the sensor nodes are continuously supplied with energy,which reduce self-carrying energy storage equipments capacity requirements.The optimal sensor node is selected through the relay selection strategy,which not only ensures the efficient and accurate information transmission,but also reduces the energy consumption of other nodes in the sensor network,it also extends the service life of the WSN.The detailed contents of this research are as follows:Firstly,Time Switching Relay(TSR)protocol and Power Splitting Relay(PSR)protocol,the outage performance of three-node relay network under the DF protocol is analyzed.The accurate closed form expression of outage probability and the approximate expression of the high Signal-to-Noise Ratio(SNR)under the two protocols are derived,and the two protocols are compared and analyzed.The optimal time allocation factor algorithm based on Steffensen iteration and the optimal power allocation factor algorithm based on Newton iteration are presented.In the stage of simulation,Monte Carlo was proceeded to verify the theoretical derivation,and the influence of various parameters on the two protocols is simulated.Secondly,in order to avoid the waste of resources,the relay selection problem of half duplex one-way communication network under is studied,which used the time switching relay protocol to harvest energy.In multiple relay networks,based on the minimum outage probability criterion,this paper studies the optimal relay problem of Partial Relay Selection(PRS)strategy and Opportunity Relay Selection(ORS)strategy.And the two accurate closed expression of the above strategies of the outage probability are derived theoretically,the correctness of the theoretical deduction is verified by simulation.Simulation results show that the outage performance of opportunistic relay selection strategy is much better than that of partial relay selection strategy.When the number of available relays increases from 1 to 15,the outage probability of partial relay selection is almost unchanged,while the outage probability of opportunistic relay selection decreases from 10^-4 to 10^-30.Finally,in order to save energy and improve spectrum utilization,the research of the outage performance and the network throughput of full-duplex wireless relay in bidirectional cooperative network is proceeded.The relay adopts full duplex communication and there are still residual self-interference signals.The two transmitting users in the model exchange information to each other through the relay node.The relay node decodes by partial decoding or joint decoding,and then recodes the transmitted signal by power superposition coding.The outage probability and throughput of transmitting users are derived.The influence of time allocation factor and power allocation factor on system performance is compared through the analysis of simulation.The simulation results show that the outage probability of full duplex communication is not only approach to half duplex communication,but also saves the communication time and network resources.