K-hop search based geographical opportunistic routing for query messages in vehicular networks

Vehicular networks provide Internet services for vehicles equipped with communication devices such as 802.11 based interface in a cheap and scalable manner. Due to the short transmission range of 802.11 and possible long distance between a vehicle and a destination, a vehicle sending a query message to a destination may require one or more vehicles to forward the message. It is critical to route the message such that the total time to arrive the destination is short with low message loss; to achieve this goal, previous geographical opportunistic routing provides a way that within the transmission range of a vehicle currently carrying a message, the vehicle attempts to find an eligible vehicle through which the message is delivered to a destination in a shorter time. If there is no eligible vehicle, the vehicle continues carrying the message. In this paper, we propose a k-hop search to find an eligible vehicle, which core idea is to enlarge the search range such that a vehicle with shorter delivery time is possibly found. Extensive simulations are conducted to study the performance, in terms of packet delay, of the k-hop search. Simulation results show that the proposed k-hop search produces significantly lower packet delay than the one-hop search.