On multihop communications for in-vehicle Internet access based on a TDMA MAC protocol

A vehicular ad hoc network (VANET) is an emerging technology which has a great potential in realizing a variety of new applications. This paper presents a new packet routing scheme which allows a vehicle to discover the existence of a gateway to the Internet and to send/receive packets to/from the gateway via multihop communications. The proposed routing scheme is based on a multichannel medium access control protocol, known as VeMAC [1], [2], using time division multiple access. The performance of this cross-layer design is evaluated for a multichannel VANET in terms of the end-to-end packet delay and the percentage of occupied time slots per frame in a highway scenario. Both packet queueing and service delays are considered in the end-to-end delay calculation by modeling each relay vehicle as a queueing system, in which the packets are served in batches of no more than a specified maximum batch-size.