Adaptive routing protocol for VANETs in city environments using real-time traffic information

An effective routing protocol for vehicular ad-hoc networks (VANETs) should have good performance regardless of the status of the network. When the network is sparse, routing protocol should work in a way to increase delivery chance. On the other hand, when network density leads to continues connection, routing protocol must choose a policy to minimize delivery delay. To realize these goals, we proposed adaptive road-based routing (ARBR). In this paper we proposed a novel routing protocol for VANETs, which is well adapted to continuously changing topology in such networks. ARBR includes a mechanism for tracking route-requesting vehicle when it leaves its expected location. When the network is sparse, we use store-carry and forward (SCF) paradigm and vehicles as ferries for overcoming the network partitioning. Finally, our protocol is compared with two VANET routing protocols, VADD and GPSR*. The obtained results show that ARBR outperforms VADD and GPSR* in terms of both packet delivery ratio and average end-to-end delay of data packets. For example, under specific conditions that was considered in the simulations, when the total number of nodes varies in networks, the packet delivery ratio of ARBR is approximately 17% better than VADD and 55% better than GPSR*.