An improved geographical routing protocol and its OPNET-based simulation in VANETs

In this paper, based on an in-depth analysis of Geographical Routing Protocol (GRP), especially its next hop selection, we present an improvement for the strategy of next hop selection with a joint consideration of distance factor and hierarchical quadrant. Based on the next hop selection strategy, an Improved Geographic Routing Protocol (IGRP) has also been proposed in this paper, which has a higher chance to deliver packets to the destinations. In order to evaluate the performance of IGRP, a VANET simulation platform is constructed by OPNET and VanetMobiSim simulators, in which VanetMobiSim is responsible for generating traffic data, and OPNET is in charge of simulating GRP and IGRP in different scenarios based on IEEE 802.11p technology. The simulations results show that IGRP can significantly improve the performance with respect to average delivery ratio, average number of hops, total backtracking number and average delay compared with the original GRP algorithm.