The Packet Scheduling Of Radio Resource Of LTE-M System For Urban Rail Transit System

Since the rapid expansion of technologies on communication,automatic control and computer science.CBTC(Communication Based Train Control)technology have been the prior choice of signal system at present.The existing train-ground wireless communication systems of signal system in urban rail transit are based on the WLAN(Wireless Local Area Network)technologies,which have many shortcomings including poor anti-interference performance,inflexible resources scheduling,inferior reliability and inconvenience of operational maintenance.The train-ground wireless communication systems based on LTE radio communication technologies are now the new trend for urban rail transit.LTE-M(LTE for Metro)system takes advantages of LTE technologies,while some critical technical issues remain to be tackled with.On the one hand,LTE-M system needs to transmit CBTC services which demands high reliability and high real time capability.On the other hand,LTE-M system needs to transmit video services which also demands high services throughput.Therefore,in order to use radio resources more efficiently and improve the performance of LTE-M system,it’s necessary to design proper scheduling strategy of radio resources for the LTE-M system,according to the features and requirements of train-ground wireless communication system of urban rail transit.This paper studies and proposes the scheduling strategy of radio resources which is applicable to scenario services of urban rail transit.Works in this paper can be mainly summarized as follow:(1)Basing on the analysis of typical resources scheduling algorithms of LTE,a scheduling algorithm applicable for multi users and services is proposed in this paper,which is call MSPF(Multi-service Proportional Fairness)algorithm and meets the demands of synthetically-bear services and QoS requirements.Simulations among MSPF and different LTE scheduling algorithms are conducted on the scenario that one use only bears single service.Results preliminary validate the performance and availability of services schedule of MSPF for LTE-M;(2)Scheduling strategies of radio resources for LTE-M system are designed basing on the proposed MSPF algorithm.Corresponding downlink or uplink scheduling strategy for single cell is designed and simulated on MATLAB.Simulation results illustrate that the designed single-cell scheduling strategy of downlink or uplink for LTE-M can schedule radio resources effectively,which meets the demands of synthetically-bear services of urban rail transit.(3)Basing on single-cell scheduling strategy and considering the problem of frequency interference,multi-cell joint scheduling scheme for LTE-M downlink resource is studied in this paper,which is based on power control.Basing on the power control for resources with same frequency,new scheme reduces the interference between adjacent cells and improves the system performance.Simulation results illustrate that newly studied multi-cell joint scheduling scheme for downlink resources can reduce the multi-cell interface effectively and further improve the system capacity.