Research On Handover And Subcarriers Resource Allocation Based On Mobile Relay In High-Speed Railway Scenario

With the rapid development of communication technology,users’ demands on the quality of wireless communication and the QoS of data service become higher gradually.In HSR(High Speed Railway)scenario,passengers on the high-speed train have to suffer the penetration attenuation,descent of handover success rate and the imbalance of resource allocation between train users and macro users along with the benefit of it,which may cause the severe influence on communication.In order to solve these problems,the fixed relay technology in the cellular network is introduced into HSR scenario to be the mobile relay,and the problems will be studied specifically.The scene is set into HSR public communication scenario with mobile relay.The thesis will focus on the simulation performance and comparison of relay-based handover,relay-based resource allocation scheme,relay-based subcarrier pairing and power allocation.The performance indicators will be identified during the handover phase in the HSR scenario.The performance enhancement of mobile relay during handover phase will be proved by simulation.Due to the frequently handover,the train in the cell may break the balance of scheduling when it comes through.A relay-based dual-queue scheduling mechanism will be proposed in this thesis.By coordinating the eNodeB and Type 1 relay,the mechanism will achieve the secondary allocation of the resources,which may balance the requirement of the cell UEs and the train UEs to increase the system capacity.Finally,the enhancement of in-train system capacity is proved by simulation.The direct link will be separated into backhaul link and access link by the relay.In LTE-A system,the subcarrier pairing between two hops and power allocation need to be optimized properly to achieve higher system capacity.In this thesis,the joint optimization will be separated into two steps to reduce the computational complexity.In the subcarrier pairing phase,the subcarriers will be paired according to the order of the channel gains based on the greedy algorithm.Based on the paired subcarriers,building and solving the optimization problem with the consideration of the influence of fast channel changing of HSR scenario may achieve optimal system capacity.In the end,the improvement of system capacity relies on subcarriers pairing and power allocation optimization is proved by simulation.