A Geocast Protocol with Information-Centric Perspective in Vehicular Ad-Hoc Networks (VANETs)

2. Related Work

Position-based routing protocols have advantages over topology-based protocols for VANET networks characterized by high mobility, which will cause the network topology to change frequently and rapidly. They share the property of using geographic position information in order to select the next hop for routing. The packet is sent without any geographical knowledge (map) to the neighbor who is closest to the destination.

GPSR and SAR are two position-based protocols. Both use routing geographic greedy but have different solutions to solve routing failures. Authors in (Karp, & Kung, 2000) propose GPSR (Greedy Perimeter Stateless Routing) protocol; which is a position-based routing protocol. It relies on the assumption that each node can get its current position and the positions of other neighboring nodes using a location service. GPSR consists of two methods for packet transmission: greedy forwarding, which is used whenever possible, and perimeter forwarding used in the regions where the first method can’t be used. Each node periodically broadcasts a Hello_Message to its neighbors that are within its transmission range, which contains a node identifier and its geographic location, so that all neighbor nodes can know its instantaneous position. Each node maintains a table of neighbors to record information about the position of all its neighbors. GPSR assumes that nodes know their own positions, either from a GPS device or by other means.