Research On Relay Cooperative Communication Based On Network Coding

With the rapid development of Internet communication technology and the full-band,full-coverage and full-application requirements of broadband mobile communication networks in the future,relay technology is one of key technologies for expanding network coverage with advantages of flexible deployment and low cost,but relay forwarding is easy to reduce bandwidth utilization.In this paper,network coding technology is introduced in relay networks,and the relay technology based on network coding is deeply studied.Because network coding technology and relay technology are collaboratively optimized,performing network coding on received signals in relay networks and broadcasting unified signals after encoding.These can reduce the number of relay forwarding,reduce channel occupancy and improve bandwidth utilization.Therefore,the relay selection and the optimization of static relay and nomadic relay scenarios are optimized to improve the reliability of static relay and the smooth real-time of nomadic relay.Firstly,based on the research of relay technology and network coding technology,this paper analyzes classifications,performance indicators,characteristics and research status of wireless relay models and their applicable scenarios.In hotspot cells where static relays are deployed,the static relay selection and relay forwarding modes based on network coding are studied to improve the reliability of communication systems.To ensure the feasibility of the scheme,application scenarios and research directions of static relays are discussed and analyzed.Then a network coding static relay selection algorithm based on Q learning is proposed in the relay cell model based on the multiple access relay channel model.The proposed algorithm and the scheme without using the relay are simulated.The results show that the network coding static relay selection algorithm based on Q learning greatly improves the reliability of the communication system,and the appropriate relay forwarding modes are selected in the case of different channel states,effectively reducing bit error ratios and outage probabilities.Finally,this paper also studies the nomadic relay selection problem based on network coding.For the communication demand that public events suddenly happen or ground communication infrastructures are damaged after disasters,the space-air-ground integrated network is used to quickly construct conmmunication network and provide communication services.A network coding nomadic relay selection algorithm based on space-air-ground integrated network is proposed.The simulation analysis and comparison simulation results of the system performance show that the proposed algorithm can significantly improves system energy efficiency and reduces the impact of network load on delay and throughput.Further research work can study network coding mobile relay selection algorithms for mobile relays deployed on vehicles.For static relays,it is also possible to study the roadside relay selection problem based on network coding for the vehicular ad hoc networks,to assist the vehicular ad hoc networks and improve the routing performance.