Highway Multihop Broadcast Protocols for Vehicular Networks
IEEE 802.11p Wireless Access in the Vehicular Environment (WAVE) standard is being developed, in order to support Intelligent Transportation System (ITS) applications including safety applications. This includes data exchange between Vehicles (V2V), and between Vehicles and Infrastructure (V2I). Safety applications, e.g., collision and other safety warnings, rely on broadcast communication. Unfortunately, 802.11p does not allow mechanisms such as sending RTS/CTS and acknowledgements for broadcast communication. Therefore, several collisions can be caused by hidden nodes/vehicles. Moreover, the possibility of using the binary exponential back-off technique to reduce congestion is not supported due to the lack of acknowledgements.