California Partners for Advanced Transportation Technology

This report proposes a spectrum efficientsolution for transmitting link travel times from vehicles to a central infrastructure. The performance of an ALOHA mobile radio system for this application is studied analytically. The average number of new updates per minute and the expected time lapsed since the latest update of the road traffic situation in a particular street section is obtained. Results show that in an urban environment, a single (cellular) radio channel has sufficient capacity if receivers are located every 5 to 10 km.