On the Frequent Acquisition of Small Data Through RACH in UMTS for ITS Applications

Wireless communications are currently considered the most promising solutions to provide real-time traffic information, suggest alternative routes, and help to reduce congestion. These new services are all based on the real-time acquisition of traffic information directly from vehicles, which act as sensors that travel on the roads. With the idea of having new widespread and real-time infomobility services in the short-medium term, neither installations onboard nor new roadside infrastructures that have been set up can be taken into account. Hence, in this paper, we aim at verifying the feasibility of the real-time acquisition of traffic information from vehicles in dense areas through the universal mobile telecommunication system (UMTS). In particular, we first analytically evaluate the capacity and the coverage of a UMTS cell when multiple users frequently transmit their traffic measurements to a remote control center through a shared (common) channel. Then, we extend our results to a realistic urban scenario by investigating, through simulations, the feasibility of the service and its impact on the quality of service (QoS) perceived by other users (e.g., voice).