Performance Modeling And Analysis Of CARQ Protocol In WPCCN Under The Interference Scenario

Recently,in energy constrained wireless networks,frequently replacing or charging batteries for wireless network devices is costly and not easily achievable,what’s more,it is not an effective and sustainable approach.However,the wireless-powered cooperative communication network(WPCCN)has emerged as a new type of network that uses radio frequency energy harvesting(RFEH)technology to extend the network lifetime and solve the problem of high energy consumption for nodes.To improve the outage probability and throughput performance of the networks,relay technology and cooperative error control technology have been extensively investigated,as well as it is also essential to take into account interference factors because of the limited spectrum resources in nature.Therefore,under the interference scenario,this paper proposes the cooperative automatic repeat request(CARQ)protocol to reduce the outage probability,improve throughput as well as shorten the energy collection time in WPCCN.The specific work is as follows:First of all,to extend the lifetime of WPCCN in the interference scenario,reduce the outage probability,improve the throughput of the system,and shorten the energy collection time,this paper proposes the energy constrained source harvests then cooperates automatic repeat request(ECS-HTCARQ)protocol.We consider a three-node model consisting of an energy constrained source node,an energy sufficient relay node as well as a destination node,besides there are two different co-channel interference sources at the relay and destination nodes,which has the advantage of a wider energy supply and transmission range.Based on the communication model,we describe the transmission process of the ECS-HTCARQ protocol and derive the closed-form expression for the outage probability under the Rayleigh fading channel.Ultimately,based on the above analysis,we establish a discrete-time Markov chain(DTMC)model to analyze the system throughput.Secondly,to further improve the system performance of the ECS-HTCARQ protocol,we extend the communication model from a single-relay to a multi-relay scenario,propose the energy constrained source harvests then relay selection cooperates automatic repeat request(ECS-HTRS-CARQ)protocol in the interference scenario,and give two relay selection schemes based on the channel state information ofS-R_j andR_j-D links.The transmission process of the ECS-HTRS-CARQ protocol is described under the multi-relay communication model,and the closed-form expressions for the outage probability of two relay selection schemes are derived.Then,we develop a DTMC model for the multi-relay scenario to analyze the system throughput.Finally,according to the expressions obtained from the above analysis,numerical simulations are performed by MATLAB.The numerical results show that the ECS-HTCARQ protocol obviously improves the outage probability and throughput performance compared to the Non-CARQ protocol at a high signal-to-interference ratio scenario,and the difference in system throughput is smaller as the number of transmissions increases,however,the outage probability is significantly reduced and the energy collection time is shortened.In addition,when the number of transmissions and relays increase simultaneously,the ECS-HTRS-CARQ protocol shows a distinct improvement over the ECS-HTCARQ protocol in terms of outage probability,throughput,and energy collection time performance.