Differentiated reliable routing in hybrid vehicular ad-hoc networks

In hybrid vehicular ad hoc networks (VANET's), roadside units (RSUs) are more powerful and robust than onboard units (OBUs) equipped on vehicles, which can exchange information and synchronize with other RSUs quickly. Due to the fast Mobility of vehicles, wireless links in VANETs are particularly vulnerable to failure. Therefore, it is necessary to provide redundancy in terms of provision multiple link-disjoint paths between source and destination. In addition, VANETs support multiple applications, such as road safety applications and commercial applications, which may require different reliabilities. Accordingly, it is important to discover different number of link-disjoint paths for different applications. In this paper, we propose two notions, virtual equivalent node and differentiated reliable path, and develop an on-demand differentiated reliable routing (DRR) protocol for hybrid VANETs. Extensive simulations show that DRR is beneficial to reduce blocking probability and to maintain lower control overhead while providing differentiated services.