TGRP: Topological-Geographical adaptive Routing Protocol for vehicular environments

Vehicular networks represent an extremely variable and unpredictable environment. Scenarios can vary from very dense and congested configurations to sparsely populated arrangements. Therefore, protocols designed for such a general scope may fail to efficiently behave in certain configurations. In this paper we propose the Topological-Geographical Routing Protocol (TGRP), a novel solution that presents an adaptive behavior by using a set of standard routing strategies. According to the scenario, TGRP chooses among four different routing approaches - two-hop direct delivery, Dynamic MANET On-demand (DYMO), greedy georouting, and store-carry-and-forward technique- to dynamically adapt its behavior to every situation. Performance evaluation shows that TGRP presents a more stable performance under different circumstances, being more adaptable to the changing characteristics of vehicular networks. In fact, TGRP outperforms DYMO by 10% in low density scenarios. In dense networks, TGRP also outperforms the Delay Tolerant Network (DTN) protocol by 10%.