Abstract: In Ad Hoc On-Demand Distance Vector (AODV) protocol, it broadcasts Request messages omnidirectionally and Hello messages periodically to build up the routing in Ad Hoc networks. But during the routing discover phase, it needs to broadcast large amount of Request messages, which weakens the performance of AODV. In this paper, a new routing protocol based on the directed broadcasting was presented. A Request message was sent through directed broadcasting, and the interval of sending Hello messages was adjusted dynamically according to the node mobility. The theoretic analysis and simulation show that the proposed scheme can reduce both the number of control messages and the routing load effectively. Besides, the performance parameters such as end-to-end delay and average deliver ratio have been improved significantly.

Key words: Ad Hoc On-Demand Distance Vector (AODV), Directional Ad Hoc On-Demand Distance Vector (DAODV), Ad Hoc network, NS-2 simulation

摘要： AODV路由协议是通过全向广播请求报文和定时广播Hello报文来建立Ad Hoc网络的路由，但在路由发现阶段需要广播发送大量的请求控制报文，导致了协议性能的下降。针对此问题，提出了一种新的基于定向广播的路由协议，该协议通过定向广播发送请求报文，并根据节点的移动性动态调整Hello报文的发送时间间隔来减少报文的发送。理论分析和仿真结果表明，该方法能有效地减少控制报文的数量，减少路由负载，也显著提高了端到端时延、平均投递率等性能参数。

关键词: AODV, DAODV, 无线自组织网, NS-2仿真