一种三维城市场景下的车载自组织网络机会路由协议

An Opportunistic Routing Protocol for Three-dimensional Urban VANETs

在真实的三维城市车载自组织网络中,车辆会分布于不同的街道层。传统的三维路由协议考虑了同层传输和跨层传输时不同的传输范围,并贪婪地选择最远的同层或者跨层邻居作为转发节点。然而这些协议忽略了链路质量较差可能会导致更多的重传。仅根据密度信息评估街道连通度会产生较大的偏差。本文基于高架的遮挡以及链路质量的变化提出了链路传输代价(CL)来评估多层街道的连通性。然后提出了一种基于CL的三维机会路由协议(OR3D)和三维场景下的候选中继选择策略。仿真结果表明,OR3D相比于传统的三维协议可以显著地降低平均传输延迟,并增加数据包投递率。

In realistic three-dimension（3 D） urban vehicular ad hoc networks（VANETs）, vehicles move in different levels. Conventional 3 D routing protocols consider the different transmission range of intra-level and inter-level transmissions, and greedily select the farthest inter-level or intra-level neighbor as relay node. However, the neglect of link quality may lead to more retransmission. Also evaluate the capacity only according to density information, which results in a big deviation. In this paper, the transmission cost of link（CL）, which concurrent considers the shadowing of overpasses and the change of link quality, is proposed to appraise the connectivity of multilevel streets. Then we propose a 3 D opportunistic routing protocol（OR3 D） based on CL and a selection strategy of candidate relay set in 3 D scenarios. The simulation results show that the OR3 D can significantly decrease the average transmission delay and increase the packet delivery ratio compared to the conventional protocol.