一种基于预测和提前认证的机车越区切换方案

Strategy of Locomotive Handoff Based on Prediction and Advanced Authentication

基于通信技术的列车控制CBTC(Communication-Based Train Control)系统是城市轨道交通信号系统的主流发展方向。WLAN自身所拥有的优势使其在CBTC系统中得到应用,其中存在的安全问题也成为研究热点。本文在对应用于CBTC系统中的无线局域网络链路层的越区切换具体过程进行深入研究的基础上,将一种基于混合Markov预测模型的WLAN越区切换机制应用于CBTC系统中,并用NS2仿真软件对该方案进行仿真,与一般硬切换过程相比较表明,该方案缩短了时间延迟,保证了列车在高速运行的情况下车地通信的实时性,并且在一定程度上减少了整个CBTC的工程造价。

Communication Based Train Control（CBTC,Communication-Based Train Control） is going to become the direction of development of the train control system.WLAN is applied in the CBTC system because of its inherent advantages whereas its security problems have turned into hot spots of research.On the basis of study on the specific handoff process of MAC of the WLAN,a new WLAN handoff mechanism based on the Hybrid Markoov Prediction Model is utilized in the CBTC system.Finally the scheme is emulated with software NS2 to prove its effectiveness and compared with the hard-handoff process.The simulation results show that the scheme shortens handoff delay substantially,realizes real-time performance of communication between train and trackside and reduces engineering costs of the CBTC system to some extent.