An Adaptive Multiple-Relay Selection in Vehicular Delay Tolerant Networks

In Vehicular Delay Tolerant Networks (VDTNs), a number of Roadside Units (RSUs) are deployed along the road and connected to the infrastructure network to provide various services to the vehicles on the road. However, it is hard to cover the long highways completely, due to the deployment cost. In such uncovered areas between two neighboring RSUs, a connection between a vehicle and an RSU cannot be established. To cope with this, few schemes have been proposed recently, enabling one RSU to select one relay vehicle to provide continuous communications for the vehicle moving in the uncovered area. However, the selection of an appropriate relay vehicle for pre-storing maximum data is an open issue. In this paper, we, therefore, propose an adaptive multiple-relay selection scheme that allows RSU to select relay vehicles while taking most relevant multiple criteria into the account. The relay selection is initiated when a vehicle is unable to receive all the data that is requested in the coverage of the RSU. The simulation results show that our scheme enables vehicles to retrieve maximum amount of the requested data in uncovered areas.