CELLULAR DIGITAL PACKET DATA FOR INTELLIGENT VEHICLE-HIGHWAY SYSTEMS

For Intelligent Vehicle Highway Systems (IVHS) to be a reality, a comm unication system, which can provide reliable communication capability in mobile environment, is needed. A cellular system capable of support ing data traffic, can satisfy many of the IVHS communication requireme nts; such as traveller information and traffic management, public tran sit monitoring and control, fleet management, truck monitoring, hazard and collision warning. Cellular Digital Packet Data (CDPD) is a data transmission service, which coexists with current cellular systems in the same frequency band and is presently being deployed. In this paper , we briefly summarize the salient features of CDPD system and evaluat e its data transmission capacity. We also study suitability of CDPD fo r IVHS applications. Our study suggests that CDPD is capable of satisf ying many of the functional requirements of IVHS. Furthermore, a matur e IVHS system (with 50 percent penetration) will need approximately 36 .5 percent of the capacity of CDPD system, even when the cellular syst em with which CDPD coexists, operates at its 2 percent Erland Capacity . With lesser penetration of IVHS, even smaller percentage of CDPD cap acity will be needed. In conclusion, CDPD seems to be a promising tech nology for IVHS and should be further explored.