A Communications Architecture Concept for ATIS

Three recent developments suggest cost-beneficial approaches to communications for Advanced Traveler Information Systems (ATIS) : 1) the use of FM subcarrier for efficient paging-type (digital) one-way broadcast, along with the upcoming introduction of Radio Data System (RDS) vehicle receivers, 2) the rapidly growing use of RF “tags” for automatic tolling, which have recently been upgraded for discrete zone two-way communication, and 3) the “signal processing gain” and “demand access” capability of spread-spectrum-type coding, which together make event-driven communications more feasible and cost-beneficial.

An architecture concept exploiting these thrusts is outlined in terms of a “baseline” and a higher level ATIS. The baseline emphasizes basic traffic exception and safety messages and supports higher level (optional) services such as navigators and invehicle route guidance computers. The baseline portion emphasizes minimum cost; overall the level-of-service choices of both the consumer and the traffic manager are maximized.