An Adaptive Geographic Routing Protocol Based on Quality of Transmission in Urban VANETs

The inherent characteristics of VANETs, such as frequent changing topology, vehicle nodes uneven density, high mobility of nodes, pose many challenges for designing an efficient routing protocol in the urban environment. In this paper, an adaptive geographical routing based on quality of transmission for urban vehicular networks (AGQOT) is proposed. As the selection guidance of road segments, a metric named as quality of transmission (QOT) is designed to measure the performance of each road segment, which combines the connectivity with packet delivery ratio (PDR). With the assistance of the metric, the road segment can be dynamically selected one by one to comprise the best routing path, avoiding the local maximum and data congestion. An improved greedy forwarding strategy is proposed to forward the packet along the selected road segment, guaranteeing the fast and reliable packet transmission. Simulation results show that the protocol proposed can improve the performance of the network in terms of packet delivery ratio and end-to-end delay.