Performance Analysis Of Relay Cooperative Transmission Based On Energy Harvesting In WSNs

Wireless sensor networks(WSNs),as an important technical carrier of information communication,are widely used in the fields of smart home,environmental monitoring,medical care,and military,which bring many conveniences to people's lives.However,energy constrained and energy consumption of sensor nodes have become the key issues affecting the performance of WSNs.Energy harvesting technology can not only fundamentally solve the problem of energy supply of sensor nodes,but also improve the performance of WSNs system such as outage probability and throughput.Therefore,this paper uses energy harvesting technology to provide energy for relay nodes,and studies the outage probability,throughput,and energy efficiency performance of multi-relay double-hop network system in WSNs.The specific work is as follows:Firstly,this paper proposes a power splitting-based double-relay cooperative transmission wireless sensor networks(PSDRCT-WSNs)protocol based on energy harvesting technology and relay cooperative communication technology.That is,the communication between the source node and the destination node is assisted by two relay nodes with energy harvesting.In addition,the paper gives a detailed description of the PSDRCT-WSNs protocol,and based on this,the mathematical expressions of the protocol's outage probability,throughput,and energy efficiency are derived.Secondly,considering the problem of energy consumption,this paper proposes an optimal relay selection scheme for cooperative transmission system of multiple relay nodes in WSNs by considering the energy harvesting status and channel status of the relay nodes.The process of selecting relay in WSNs is divided into two stages: 1)a threshold is set for the energy of the relay node at the beginning of the transmission,and those who meet the threshold condition can obtain the qualification for selection;2)the relay node with the best channel state is selected from the relay nodes that meet the energy threshold condition for auxiliary transmission.According to the energy harvesting of relay nodes,a finite state discrete-time Markov model is established,its steady-state distribution is solved,and mathematical expressions of the outage probability,throughput,and energy efficiency of WSNs system with multiple relays selection cooperative transmission are derived.Finally,according to the above analysis expressions,the effects of the location of relay nodes,power allocation ratio,energy conversion efficiency,number of relay nodes and number of discrete energy blocks on the WSNs system performance are analyzed by MATLAB numerical simulation.the reasonable range of power allocation ratio is given according to the WSNs system with multiple relays selection cooperative transmission in this paper to ensure the best performance of the system.