The most critical element of Intelligent Vehicle Highway Systems (IVHS) will be the communication system that links the highway infrastructure and mobile vehicles. Not only must it be designed to allow users who purchase systems in one city to travel or permanently move to another, but also it must support robust, relatively high-capacity data communications, at least in the infrastructure-to-vehicle (ITV) direction, and have a cost that is in balance with the perceived benefits that the overall IVHS system provides to users. The availability of ITV communications, in particular, is essential to the implementation of nearly all other aspects of IVHS. As a result, a need exists to expedite the definition. development and implementation of this subsystem. It is in fact more important to provide an early ITV communications capability in order to support other IVHS developments than it is to ensure that the first ventures into this area are the "best" solutions to long-term IVHS needs. This paper discusses the requirements for mobile communications in the early implementation phase of IVHS development, defines a design for providing this service, and proposes a communication system architecture that will support early IVHS development while allowing for evolutionary, incremental improvements as the needs of the overall system are defined. Finally, a short field experiment is described, which will be used to validate the simulation that were used to refine the system definition. (A) This paper was discussed by O Yamada on p. 100, with the authors' reply provided on p. 100-101 of the same issue.
Abstract