Multi-channel mode for emergency system in urban connected vehicles

Traffic safety applications exploit vehicle-to-vehicle communication is an emerging and promising area within the intelligent transportation system (ITS) environment. This objective would be achieved essentially by the employ of efficient safety applications which should be able to wirelessly broadcast warning messages between neighboring vehicles in order to inform drivers about a dangerous situation; such as accidents in a timely manner. To ensure their efficiency, safety applications require reliable periodic data dissemination with low latency. IEEE 1609.4 defines a MAC layer implementation for multichannel operations in a vehicular ad hoc network (VANET). In this light we proposes a novel multi channel mode protocol for emergency systems to improve the channel utilization of the control channel (CCH) and uniformly distribute the channel load on service channels (SCHs). In the proposed protocol, network change their modes from general to emergency mode to increase the probability for a message to arrive in time. The scheme reduces the rate of transmission collisions which create latency and improves the reliability of message delivery in time. Furthermore, extensive analysis and simulations are presented.