3MRP+: An Improved Multimetric Geographical Routing Protocol for VANETs

The design of routing protocols in vehicular ad hoc networks (VANETs) is fundamental to achieve a high packets' delivery ratio. Routing protocols whose operation considers the nodes' positions use updated routing information according to the reception frequency of hello messages. The routing information can help to improve the routing operation by including several metrics such as vehicle's trajectory, vehicle's density, percentage of packet losses, among others. In addition, there is a trade-off between the beaconing frequency and the overhead injected to the network: a high frequency provides a better accuracy on selecting the best forwarding node to route a packet but at the same time the overhead is increased. However, a low frequency will provide less accuracy on selecting the best forwarding candidate node but the overhead injected to the network will be decreased. In this paper, we have designed an efficient method to improve the accuracy of the nodes' position used to select the next forwarding node without any modification on the beaconing frequency value. Our approach improves the operation of the routing protocol used in our performance evaluation. Simulations show the benefits of our proposal, increasing the accuracy of the nodes' selection and maintaining the same level of overhead, without the necessity to increase the beacon frequency.