Opportunistic Broadcasts in Vehicular Networks
In this chapter, we apply the concept of opportunistic routing in broadcasts in vehicular networks. Vehicular ad hoc network (VANET) is a special type of mobile MWN designed to provide a wide range of road applications such as safety warning (Torrent-Moreno et al. 2009; Xu et al. 2004), congestion avoidance or mobile infotainment (Li et al. 2011). One important function of VANET is the broadcast of event-driven warning messages (WMs) like accident and hazard warning, for example, after two vehicles collided with each other on a highway, or traffic congestion happens because of heavy rain or snow, the upcoming vehicles need to be notified immediately. In both cases, the WMs should be disseminated with only a short delay to vehicles that are up to several kilometers away, not only to prevent more possible accidents but also to enable the vehicles to make a detour as early as possible to avoid congestion. While Dedicated Short Range Communication (DSRC) (http://www.standards.its.dot.gov/Documents/advisories/dsrcadvisory.htm) allows the data transmission range of vehicles to be up to a few hundred meters, a single-hop broadcast is not sufficient to provide the desired warning message coverage. So a multihop broadcast is necessary to disseminate time-sensitive warning messages in VANETs.
There are three main performance goals in WM broadcast in VANETs. 1. High reliability, which is usually measured as the percentage of vehicles ...