Data Transmission Strategy Design Of Relay Network Based On Energy Harvesting

The rapid development of 5G technology puts forward great requirements for the energy supply of wireless devices.Energy harvesting(EH)technology can replace the traditional power supply mode to meet this requirement.Therefore,this thesis mainly studies the relay network under energy cooperation.Specific work includes the following:Firstly,aiming at the problem of energy hole problem caused by frequent use of relay nodes in wireless sensor networks,a single relay system based on energy cooperation is proposed.The scheme assumes that the distribution position of the relay node obeys the Poisson point process,and that the source node and the relay node can harvest energy from the environment.When the source transmits a signal to the relay,some energy is also sent by the source to the relay.According to battery storage state the source transmits its data to the destination either directly or cooperatively by the relay.Combined with the position of the relay node and the steady-state distribution of the battery,the system outage probability performance is derived.The optimization model is established to minimize the system consumed energy.The particle swarm algorithm is used to get the optimal system parameters.Simulation results verity the performance of the proposed model.Secondly,this work deals with the problem of insufficient energy caused by the frequent use of relay nodes in wireless sensor networks.Here,energy cooperation relay selection(ECRS) algorithm is proposed in energy heterogeneous networks.It is assumed that the location of relay nodes obeys a homogeneous Poisson point process(PPP),and the relay nodes adopt an adaptive energy collection technology,which can harvest energy from the surrounding environment and decide whether to use or store it according to the current energy status of the battery.The relay nodes are divided into three kinds: the communication relay,the candidate relay and the ordinary relay.The candidate relay nodes are determined by KMedoids clustering algorithms and the ordinary relay nodes transmit energy to them.Finally,the number of data packets sent by relay nodes and the expression of the energy status of the battery are derived correspond to the relay cooperation selection algorithm.The simulation results show that the ECRS scheme effectively extends lifetime of the network when the total network energy is relatively small.Finally,the physical layer security performance based on simultaneous wireless information and power transfer(SWIPT)is studied.The eavesdropper distribution is modeled as a PPP,and three relay selection schemes based on SWIPT are introduced,namely random relay selection(RRS)scheme,best relay selection(BRS)scheme and multiple relay selection(MRS)schemes.The physical layer security performance of the three relay selection strategies is analyzed.The simulation results show that when there are multiple candidate relays,the proposed BRS scheme has better security outage performance than the RRS scheme.The more the number of candidate relay nodes,the better the system performance under the BRS scheme.And its interrupt performance is related to the distribution of eavesdropper nodes,the greater the density of eavesdropper distribution,the worse the security interrupt performance.When the number of candidate relay nodes is fixed,compared with three relay selection schemes,MRS schemes are more suitable for poor channel communication scenarios.