Data dissemination for heterogeneous transmission ranges in VANets

Distance is a key measure when implementing timer-based dissemination protocols in Vehicular Ad-hoc Networks (VANets). In which the transmission is deferred proportional to distance, aiming to order vehicles transmission, such that the farthest vehicle gets the highest opportunity to relay the message. This will ensure long hops along the road to speed up the dissemination and cover more nodes. However, in case of heterogeneous transmission ranges, the farthest distance will not ensure a proper choice of relay nodes to disseminate the message. Vehicles, whose transmission area enclosed by the sender or have small non-covered transmission area, might be chosen as relay vehicle. This may inhabit other nodes from relaying the message and end the dissemination process early and before it reach the required region. In this paper, we propose the Area Defer Transmission (ADT) dissemination algorithm. ADT enables each vehicle to independently decide to transmit or suppress transmission considering heterogeneous transmission ranges and the amount of area that would be covered by potential new transmission. The performance of the proposed ADT algorithm has been evaluated using an actual road map with complex road scenarios and real movement traces. It has also been thoroughly investigated and compared with other distance-based algorithms. The results demonstrate that ADT achieves high delivery ratio, high propagation speed and less relay ratio with fewer hops that reach long distances.