中文摘要：

针对城市车载自组织网络环境中节点分布不平衡,信号传输被障碍物遮挡,目标节点不断移动等问题,提出一个适合城市环境基于地理位置信息的自适应路由协议SAGR（Self-Adaptive Geographic Routing for city environments in vehicular network）.SAGR通过远程混合模式被动路由机制SAGR-RM和局部定向受限泛洪路由机制SAGR-LM,将路由过程分成两个层次,增强了路由协议的健壮性以及对目标位置的容错性.通过NS-2软件仿真分析了SAGR协议的性能,结果表明SAGR比现有的基于位置路由协议在数据包传输、端到端延迟和路由开销方面等都有显著的改进.

英文摘要：

Routing protocol based on geographic location in Vehicular Ad hoc Network gets the extensive attention for its high scalability, but location-based routing protocols usually have to face the problems with topology changes frequently, hard to solve local optimization, fuzzy characteristics and low fault tolerance of the target location, especially in urban environments, if only depend on the location based information, it is difficult to forward data effectively. So the main job of our article is aiming at resolving node distribution imbalance in urban environment. We propose a Self-Adaptive Geographic Routing protocol for city environments in vehicular network（SAGR） considering the limitations including the high speed of flow, the failure of transmission and the movement of target node. The SAGR routing process is divided into two levels with remote passive routing mechanism mixed mode SAGR-RM and limited local directional flood routing mechanism SAGR- LM two routing mechanism, which greatly enhance the routing protocol of robustness and fault tolerance of the target location. We describe the details of our scheme and use the NS-2 simulation platform to simulate and analyze the performance of SAGR protocol. Simulation results show that the SAGR is significantly improved in packet delivery rate, end-to-end delay and routing overhead.