Mobile radio services for urban transport
C C Bantin · WIT transactions on the built environment · 2006
Mobile IP networks, using wireless LAN (WLAN) technology, have recently been successfully deployed for communications based train control (CBTC) applications.Packet transmission networks are well suited to the data communications requirements of CBTC, and WLANs, using universal data packet (UDP) transmission, a simple send and forget protocol, are ideally suited for this task.Moreover, the 802.11family of WLAN radio standards allows for several megabits per second of data transmission, whereas automatic control applications require at most 10 to 20 kb/s data links.This leaves ample capacity for carrying additional data to and from transit vehicles, and opens up the possibility of providing additional data services.Transit operators are becoming increasingly interested in utilizing this extra capacity for CCTV, voice and emergency response services.WLAN radios can carry varying amounts of data for these additional services from one CCTV signal plus voice and data for basic 802.11, to several high-quality video signals and voice circuits for 802.11g systems.