Emergency Broadcast Protocol for Inter-Vehicle Communications

The most important goal in transportation systems is to reduce the dramatically high number of accidents and fatal consequences. One of the most important factors that would make it possible to reach this goal is the design of effective broadcast protocols. In this paper we present an emergency broadcast protocol designed for sensor inter-vehicle communications and based in geographical routing. Sensors installed in cars continuously gather important information and in any emergency detection raise the need for immediate broadcast. The highway is divided in virtual cells, which moves as the vehicles moves. The cell members choose a cell reflector that behaves for a certain time interval as a base station that handle the emergency messages coming from members of the same cell, or close members from neighbor cells. Besides that the cell reflector serves as an intermediate node in the routing of emergency messages coming from its neighbor cell reflectors and does a prioritization of all messages in order to decide which is the first to be forwarded. After this the message is forwarded through the other cell reflectors. Finally the destination cell reflector sends the message to the destination node. Our simulation results show that our proposed protocol is more effective compared to existing inter-vehicles protocols