Analysis on the Interruption Time for CBTC Handover
Lijie Chen, Tao Tang, Jidong Lv · Zhongguo tiedao kexue · 2010
Communication Based Train Control(CBTC) system adopts IEEE 802.11 standard as the wireless communication protocol.According to the handover procedure specified in IEEE 802.11 standard,the relational expression between the interruption time for handover and the train speed was derived by using the calculation method of the interruption time for handover in the mobile communication system.The results of the theoretical calculation by the relational expression show: on condition that the transmit power is 17 dBm,the gain of both the transmitting and the receiving antenna is 10 dB,the loss of both the transmitter and the receiver is 5 dB,and when the typical train speed is 50,70,90 km·h-1, the interruption time for handover should be within 224,160,124 ms in order to guarantee the continuously normal communication.The model of two trains tracing was established to simulate the rear train speed-distance curve with different interruption time for handover.The simulation results show that when the train speed is 25 m·s-1(90 km·h-1),less than 130 ms of the interruption time for handover can satisfy the demand of train communication,which verifies the relational expression between the interruption time for handover and the train speed to be reasonable.