A Survey of Unicast Routing Protocols Based- Greedy Forwarding Strategies for Vehicular Ad–hoc Networks in Urban Scenario

A vehicular ad hoc network (VANET) is a new technology that allows vehicles to form a self-organized network without reliance on permanent infrastructure. The characteristics of VANET such as rapid topology changes, high mobility, and frequent link disconnections makes it difficult to design an efficient routing protocol for routing data among vehicle to vehicle communication (V2V). Existing greedy routing protocols for VANET are not efficient to meet every traffic scenario such as low traffic densities. There are large numbers of surveys that have studied different greedy routing protocol categories. We select a limited, but representative number of these surveys to be reviewed in our work. This survey intends to provide a comprehensive review of these categories of greedy routing protocols. In this paper we provide a survey of greedy routing protocols for a vehicular ad-hoc network, and present a timeline of the development of existing greedy routing protocols. We discuss the advantages and disadvantages of these routing protocols and define some current issues and possible directions of future research related to using greedy routing protocols. Finally, we investigate and compare several greedy algorithms designed for urban VANET. A qualitative comparison of these approaches can serve as a guideline for network designers to choose appropriate greedy routing protocols to meet network application objectives.