Routing protocol for complex three-dimensional Vehicular Ad Hoc Networks

Due to the existence of three-dimensional (3D) scenarios in realistic Vehicular Ad hoc Network (VANET), such as the viaduct, tunnel and ramp, the distribution of vehicles is 3D. To the best of our knowledge, the issue of designing a routing protocol for 3D VANET has rarely been studied. Our previous work [10] has provided a Three-dimensional scenario oriented Routing (TDR) for the simple 3D scenario which contains two or more parallel roads with different heights. Because the distribution of nodes in the complex 3D scenarios has no rules and no obvious stratification phenomenon, TDR is not suitable for the complex 3D scenarios. Here the complex 3D scenarios are these flyover scenarios with many ramps and irregular arrangements in a large range. Therefore, we propose a novel routing protocol Complex Three-dimensional scenario oriented Routing (C-TDR) for the complex 3D scenarios. In C-TDR we introduce the concept of virtual neighbor and the completion process of neighbor list considering the feature of fluctuant transmission range of nodes in 3D VANET. Finally, we build a simulation scenario containing the simple 3D scene and the complex 3D scene and conduct the simulation for C-TDR. The C-TDR is shown to increase the packet delivery rate and decrease the end-to-end delay and hop count.