OFA: Opportunistic forwarding and acknowledgement for vehicular ad hoc networks

In vehicular ad hoc networks (VANETs), providing a multi-hop communication is challenging due to the vehicle movement and lossy feature of wireless channel. Opportunistic routing provides an alternative solution with its utilization of the broadcast nature of wireless communication and the diversity of packet reception. However, most of opportunistic routing protocols specify the forwarding nodes at the sender side and therefore the opportunism cannot be fully utilized. Moreover, existing opportunistic routing protocols cannot provide a high reliability because of the lack of efficient packet reception check mechanism. In this paper, we propose OFA, an opportunistic forwarding and acknowledgement protocol for vehicular ad hoc networks. OFA performs both data forwarding and acknowledgement by taking advantage of multiuser diversity and route opportunism. In OFA, the forwarder node selection occurs at receiver nodes. An intermediate node is selected opportunistically to acknowledge the sender on the behalf the forwarder node when the forwarder node cannot communicate with the sender node directly. The proposed protocol can fully utilize the path diversity and also can provide hop-by-hop reliability.