Unicast Routing among Local Peer Group (LPG)-Based VANETs

In recent years, there have been significant efforts related to vehicle-to-vehicle (V2V) communication. The major demand of the V2V communication was originally from safety-related applications; and the possible application areas including communication support for auto-navigation have increased. Local Peer Group (LPG) is a partitioning structure to promote quick deliveries of time- sensitive information and efficient use of wireless media. LPG organizes vehicles into manageable vehicle groups prior to a need for delivering relevant emergency messages, and provides efficient data dissemination (both multicast and unicast) among vehicles. In this paper, we first provide an overview of LPG structure and proactive unicast inside LPG. As the focus of this paper, we then present a new on-demand unicast routing protocol that supports inter-LPG communications - with aspects of route search, establishment and maintenance. Our preliminary simulation results indicate that our proposed inter-LPG unicast routing protocol has control overhead that is significantly lower than the conventional on-demand routing protocols.