Performance Analysis Of Cooperative ARQ Protocol Based On Multi-relay Switch In Wireless Sensor Networks

In the process of information modernization,sensor networks occupy a vital position as a common method of collecting information in people's production and daily life.However,in the sensor network,due to the complexity of the environment and the specific application of the particularity of the scene,the reliability of the network is difficult to be guaranteed.And due to many physical constrains,communication capacity of the sensor nodes is much weaker than the ordinary terminal.In practical applications adverse working conditions often result in a particularly poor link channel condition that causes data reception failures.In order to ensure the reliability and transmission efficiency of the transmission data,the retransmission strategy combined with the relay cooperation technology in the sensor network is the hot spot of many scholars.In this paper,the CARQ(Cooperative Automatic Repeat Request)scheme based on inter-cluster switching and multi-relays switching in intra-cluster is studied.And the system still has significant performance gain when the direct link channel is poor.The main research contents are as follows:1.In order to meet the requirements of sensor network for transmission reliability and transmission efficiency,a CARQ protocol based on inter-cluster switching is proposed.First,the protocol selects optimal node in each cluster based on the channel capacity as the index.Then,the steady-state selection probability of the link of the communication link S-Ri-D is analyzed.Finally,the sensor network is used as the research model,and the outage probability and energy efficiency of the system are analyzed when inter-cluster switch.The analysis and simulation show that the proposed protocol can better guarantee the transmission efficiency of the system.Especially when the number of members in each cluster increases,the performance of the system can be improved remarkably.2.In order to solve the problem of low system retransmission efficiency when the direct link fading is more serious,a CARQ protocol based on multi-relays switching in cluster is proposed.The protocol based on the principle of optimal path selects multiple available nodes within the cluster for retransmission.When the direct transmission fails,multiple-relays retransmit the data through the switching.The received plurality of data is made maximal-ratio combining at the destination node D.The relationship between system performance and the number of switching attempts is quantitatively analyzed with throughput and average bit error rate as the evaluation criteria.The simulation results show that the proposed intra-cluster switching protocol can bring a good gain to the performance of the system.Which provides a reference for the design of multiple relay in the system.