Packet-switched cellular communication architecture for IVHS using a single radio channel

This paper proposes a radio architecture that offers two-way transmission services essential to intelligent vehicle highway systems (IVHS) using only a single (30 kHz) radio channel. Within this bandwidth multiple communication services can be supported, including datacasting, packet switched transmission to and from vehicles, collection of traffic data from probe vehicles and transmission of emergency messages. The design is based on theoretical investigations reported at PIMRC ´93 and VTC ´94 on packet-switched downlink transmissions and ALOHA random access for traffic reports from probe vehicles, respectively. These analyses revealed that contiguous frequency reuse gives optimum packet delay and highest spectrum efficiency. New results are included for datacasting messages to groups of vehicles