Comparative analysis and applicability of routing protocols in VANETs

Though a Vehicular Ad Hoc Network (VANET) is an instance of MANETs, the relative rankings of legacy protocols from MANETs may exhibit an enormous variation in VANETs. Therefore a comprehensive analysis of the performance of the routing protocols is desired to find the applicability of them in vehicular-specific conditions. Through this paper, an attempt has been made to analyze the performance of the routing protocols (OLSR, DSDV, AODV and CLWPR) in realistic mobility and radio propagation models. Manhattan Grid mobility which greatly emulates the motion of vehicles in an urban city is used. The probabilistic Nakagami radio propagation model is sequentially added over the three deterministic path loss models (Friis Propagation, Two Ray Ground and Log Distance Path Loss) to represent channel fading characteristics of urban scenarios. The performance metrics of packet delivery ratio (PDR), end-to-end delay, throughput and jitter has been measured for each routing protocol under a scenario where either the network traffic or the node density affects the communication reliability. It is seen that in most simulation results, proactive routing protocols (OLSR and DSDV) and the position-based routing protocol (CLWPR) performed significantly better than the reactive routing protocol (AODV).