Research On Emergency Message Broadcasting In Vehicular Ad Hoc Networks

Every year many people lose their lives or get injured on roads and a huge amount of timeand fuel are exhausted because of road accidents or traffic jams. That is why one cansafely say that broadcasting of Emergency Messages (EM) in the Vehicular Ad HocNetworks (VANETs) plays a significant role in safety applications, which requireimmediate broadcasting of EM to the relevant vehicles located in the Risk Zone (RZ) inorder to make the vehicles able to change their lanes or slow down to get road accidentsand traffic jams reduced effectively. As a result, people, time, and fuel can be saved.In this thesis, we propose an Efficient Emergency Message Broadcasting (EEMB) schemein VANETs. This scheme aims at avoiding multiple accidents and reducing traffic jamsthat take place on roads by broadcasting EM to the relevant vehicles located in the RZ asquickly as possible (high speed) and with minimum overhead (low overhead). When anaccident takes place on the road, the crashed vehicle will choose the best relayer(s) fromits one-hop neighbors and then it generates and broadcasts the EM. The relayer will alsochoose the best next relayer(s) and rebroadcasts the EM further and so on. This taskcontinues so as to cover the entire RZ by EM. The EEMB scheme handles the overheadcaused by beacons exchanging between vehicles through using the prediction method, inwhich more information adds into beacons. The vehicles can use this information topredict their one-hop neighbor’s location, thus, providing a more accurate localization ofvehicle’s neighbors while using beacons exchanging at a lower number. Our proposedscheme also overcomes the network fragmentation problem which is a frequent one inVANETs, especially in the sparse network by using the vehicle s moving on the oppositedirection to be chosen as a relayer(s) if there are no vehicles moving in the same direction.And EEMB scheme using of store-carry-forward mechanism when there are no vehiclesmoving on both directions. The simulation results have shown that the proposed schemehas better performance than the existing one in terms of the Risk Zone Latency (RZL) andthe Beacons Overhead (BCO).