Radio Resource Management Based On Soft Frequency Reuse And Train-to-Train Communication In Urban Rail Transit System

As a subsystem of the CBTC(Communication Based Train Control)system,the performance of train-wayside wireless communication system plays an important role in CBTC system.Train-wayside wireless communication system based on LTE-M(LTE for Metro)technology,which has been preferred in wireless communication system in urban rail transit systems,has a series of advantages including supporting high speed,strong anti-interference and flexible resource scheduling.LTE-M system could bear multiple services to satisfy production requirements of urban rail transit systems.The Qo S(Quality of Service)of different services vary greatly.In this thesis,the features of services in urban rail transit system are analyzed,combined with different wireless communication scenarios.And the algorithms consist of radio resource management based on SFR(Soft Frequency Reuse)and train-to-train communication.The works of the thesis are summarized as follows:(1)The research status of radio resource management in mobile cellular networks are introduced,and the policies of resource management aiming to different services,together with the significance of implementing train-to-train communication with D2D(Device-to-Device)communication based on LTE,are analyzed;The channel models of special wireless communication environments in urban rail transit system are summarized and the technical features and communication modes of train-to-train communication based on D2 D communication are analyzed.Then the resource scheduling models of train-wayside communication and train-to-train communication are designed,respectively.(2)To eliminate the effects of the rapid channel quality due to the fast moving train and the serious interference at the cell edges,heuristic dynamic resource scheduling algorithms are proposed to improve the minimum throughput of trains in cells.The algorithms are designed based on the architecture of SFR,and operated with joint allocation of resource and power according to real-time wireless channel quality of trains.And the property of local convergence of the algorithms is proved.Then the proposed algorithm is compared with no optimization algorithms and other ICIC(Intra-cell Interference Coordination)algorithms through simulation experiments.The results show that the proposed algorithm could improve the minimum throughput of trains effectively and keep the throughput of trains relatively stable during the train operation.(3)Considering the coexistence of train-to-train communication and trainwayside communication,the radio resource management algorithms based on Stackelberg game are proposed to coordinate the Qo S requirements of two communication methods.And the optimal solution of the game are theoretically illustrated.The results show that the proposed algorithm could guarantee the Qo S of services beared on train-to-train communication and train-wayside communication and improve the reliability of CBTC system effectively.This thesis has 46 figures,12 tables,82 references.