Hop count analysis of location aided multihop routing protocols for VANETs

Vehicular ad-hoc network (VANET) is an important technology for future development of intelligent transportation systems. VANETs are being used as a tool for improving road safety by warning the drivers about accidents occurred ahead of them or for providing internet access to the passengers via gateways along the road. Although VANET is an application of MANETs but routing of data packets is more challenging in VANETs. This is because of frequent change in network topology due to the highly-dynamic nature of vehicular nodes. Researchers have developed various routing protocols for VANETs and hop count among others is considered as an important metric in evaluating these protocols. LAR (Location Aided Routing) and D-LAR (Directional-LAR) protocols are well known position based routing protocols for VANETs. In this paper we have proposed another protocol which is an important extension of D-LAR and which improves upon hop count in comparison to both LAR and D-LAR protocols. This protocol uses distance in addition to the directional routing strategy to select the next hop node, which results in a stable and shorter route. We have devised a generic HopCount Algorithm to compare the three protocols. Simulations are done to corroborate algorithmic analysis for multiple scenarios which depict dense environment. Performance results clearly depict that DD-LAR outperforms the other two protocols and with an increase in transmission range or vehicular density, hop count value is further reduced.