Semantic and self-decision geocast protocol for data dissemination over VANET (SAS-GP)

In this paper, a semantic and self-decision geocast routing protocol for disseminating safety and non-safety information over VANET (SAS-GP) is presented. SAS-GP initially executes an algorithm for locally determining the semantic geocast area. Then, the protocol disseminates the information in three phases: Spread, Preserve, and Assurance, which utilize the traffic information system and the digital map. SAS-GP principally employs timer-based techniques in order to avoid overhead; nonetheless, novel factors are enhanced to calculate the values of each timer in the three phases. Simulation results demonstrate effective and reliable dissemination in terms of delivery ratio and number of false warning compared to existing protocols when evaluated in high scale and realistic scenarios. Also, SAS-GP performs faster in notifying vehicles resulting a higher geocast distance before approaching the location of the event.