Abstract: This paper proposes a routing protocol that incorporates greedy forwarding and directional forwarding based on geographical position called，GDGP.The position information of the destination nodes stored on every node could be updated through two independent message interactive mechanisms，which makes sure of the consistency of the position information recorded on every node.This further ensures the reliability of the routing algorithm.The performance of GPSR and GDGP is compared by using network simulator NS-2 with the actual node movement model.The simulation results show that the improved routing protocol has a better performance in city scenes.

Key words: vehicular Ad hoc networks, greedy perimeter stateless routing, directional forward

摘要： 提出了一种新的基于地理位置信息的车载网络路由协议——GDGP。GDGP是一种包转发机制，在进行包转发时将贪婪转发与方向转发相结合，通过两个独立的消息交互机制，更新各个节点上存储的目的节点的位置信息，以确保各个节点上记录的目的节点的位置信息的一致性，进而保证路由算法的可靠性。利用NS-2仿真平台，采取接近现实车辆运动情况的节点运动模式进行实验，和已有的GPSR路由协议进行比较。仿真结果表明，改进的路由协议在城市场景中有较好的性能。

关键词: 车载自组织网络, 贪婪的周边无状态路由, 方向转发