Research On Relay Selection Algorithms In Network Coding Aided D2D Communications

The rapid development of wireless technology has led to an explosive growth in the number of mobile devices.To reduce the burden on the base station and improve resource utilization,Device-to-Device Communication(D2D communication)has been proposed.However,direct D2 D communication is more suitable for short-distance and slow-speed devices,so the introduction of relay users to expand communication coverage and solve the drawbacks of direct D2 D communication.However,it also causes interference and increases the number of forwarding.Therefore,it is considered to combine with network coding technology to suppress interference and improve transmission efficiency.In network coding assisted D2 D communication systems,the choice of relay users is critical.This thesis closely combines the actual situation of the application scenarios in the network,builds a network coding assisted D2 D communication system model with three different topologies,and then proposes a corresponding relay selection sch eme.The simulation results show that the network coding and the proposed rel ay selection scheme are adopted can improve the performance of the system.The main research contents of this thesis are as follows:First,the network coding auxiliary D2 D single relay communication system model is established,the establishment of the communication session and the specific communication process of each time slot are introduced.A relay selection scheme considering joint end-to-end rate,delay and relay survival time is proposed.The effect of network coding and different relay selection schemes on the end-to-end transmission data volume and delay is simulated.The results show that the relay selection scheme based on network coded auxiliary communication can improve the end-to-end information volume of the system and reduce the transmission delay.Second,a network coding auxiliary D2 D multi-relay communication system is constructed for communication scenarios that require high reliability.The model session establishment and specific communication process are introduced in detail,and the packet loss performance of the system is analyzed.In order to avoid data redundancy and resource waste while improving reliability,it is necessary to minimize the number of relay users and the number of transmissions.Therefore,a relay selection scheme combining geographic location,channel quality,relay transmission times and survival time is proposed.The simulation results show that the scheme improves the system throughput and reduces the packet loss rate and enhances the reliability.Third,a network coding assisted multi-pair D2 D single-relay communication system is constructed for the case where multi-user access and idle users are limited.The model session establishment and communication process is introduced and the system capacity is analyzed.In order to improve system capacity and ensure reliable communication,a relay selection scheme combining joint geographic location,communication content,survival time and system capacity is proposed.Simulation results show that the scheme improves system capacity and channel utilization.