Location-aided gateway advertisement and discovery protocol for VANets: Proof of correctness

The Internet access from vehicular networks is gaining great interest from the research community. In fact, vehicles should be able to connect to the Internet and communicate with different networks through gateways. Guaranteeing safety on the roads is the main objective of vehicular networks. Safety applications need to collaborate with other types of services for efficient safety assurance. Consequently, many services would coexist with safety applications, including the gateway discovery service, and share a limited bandwidth. Any solution to the gateway discovery problem in vehicular ad hoc networks (VANets) is subject to this limitation. In this work, we present a novel gateway discovery technique for VANets. Our protocol aims to provide an efficient hybrid adaptive location-aided gateway advertisement and discovery mechanism for VANets (LAGAD). It has the following unique and novel characteristics for gateway discovery in VANets: (i) it is built on top of the network layer; (ii) it uses channel diversity; (iii) and it is based upon a location-aided adaptation of the advertisement zone of the gateway. Our proposed protocol benefits from the routing information to find the gateway service and the routing information to the gateway at the same time saving the overall bandwidth. It uses diverse channels to exchange discovery and routing packets decreasing the congestion on single channels and decreasing the delay of gateway discovery. Our proposed gateway discovery protocol adapts the advertisement zone of gateways based on the location information and the velocity of requesting vehicles. We discuss the implementation of our algorithm, then present its proof of correctness and message and time complexities computations.