A Novel Priority Based Exigent Data Diffusion Approach for Urban VANets

With the rapid development of urbanization, the tendency of road accidents is also highly increasing due to heavy traffic. Most of the victims give up their lives because of the insufficient infrastructure of emergency information distribution to the proper authorities and lack of critical care on urgent basis. Besides restricting the preventable causes like over speeding, drunk-driving and overloading, it is very important to propagate emergency messages across the network to deal with such disasters. This paper presents a novel scheme for disseminating messages on priority basis over VANets in urban scenarios, which take care of the fairness of the scheduling process by introducing precedence on the emergency messages like the lifesaving message or other critical message over general messages like traffic condition, fuel pump and road condition and or all other commercial messages. For this a laxity based priority scheduling technique with back-off mechanism is introduced. The next packet is to be transmitted based on certain parameter like: its priority considering the laxity budget of the packet, the present packet delivery ratio, required packet delivery ratio and the request selection precedence. To provide the fairness in the scheduling process the request selection precedence is introduced which scheduled the most urgent request for service in the next iteration. The EXata simulator has been extensively used to assess the proposed scheme. The proposed method has been found to work satisfactorily with a number of test cases and considerably outperforms compare to the existing technique.