Ad Hoc网络按需路由协议的改进  

An Improvement to Ad Hoc On-demand Routing Protocol

作　　者：余旭涛[1] 毕光国[1] 王霄峻[1] 张在琛[1] 

机构地区：[1]东南大学移动通信国家重点实验室,南京210096

出　　处：《计算机学报》2004年第6期838-844,共7页Chinese Journal of Computers

基　　金：国家"八六三"高技术研究发展计划基金 ( 2 0 0 3AA12 3 2 3 0 );国家自然科学基金 ( 60 3 72 0 5 4)资助

摘　　要：DSR和AODV路由协议是两种用于adhoc网络的按需路由协议 ,随着网络负荷的增加 ,协议的性能下降很快 .针对这一问题 ,该文对节点链路层的性能进行了分析 ,提出了一种均衡流量的改进方法 .在该方法中 ,路由层根据节点链路层当前的负荷状态决定是拒绝或接受收到的路由请求 ,弥补了上层协议仅反映端到端网络状态的不足 ,直接反映了网络中节点的当前状况 ,避免了网络的局部拥塞 ,均衡了网络流量 .仿真结果表明 ,无论对DSR协议还是AODV协议 ,采用该算法均明显地提高了网络效率 .并且由于该算法简单易行 ,因此具有实用性 .The two on-demand protocols for ad hoc networks——DSR and AODV show degraded performance with increased traffic load. We found, through analysis and simulations, that local congestion in the network is the main reason for this performance degradation. In this paper, we propose a link-layer-aware traffic-balanced scheme to solve this problem. In the proposed scheme, routing model at a node accepts or rejects a routing request based on congestion status at the link layer. Basically, if the node is congested at the link layer, it will discard an incoming routing request if the node is not the destination node of the routing request; otherwise, the routing request will be processed as in the original DSR or AODV protocol. In this way, congested nodes will not be involved in new routes and traffic is balanced in the whole network. Different from upper layer congestion control protocols which use only end-to-end information and have no exact information in the network, the proposed scheme adopts link layer information for more effective control. Simulation results show that the new scheme significantly improves DSR and AODV’s performance under heavy loaded conditions. And with higher network load, we have larger performance improvement. When the network load is 200Kbits/s, network throughput has 35% and 26% improvements if the proposed scheme operates on the DSR and AODV protocols, respectively. The new scheme is also easy to implement.

关 键 词：Ad HOC网络 按需路由协议 DSR路由协议 AODV路由协议 网络负荷 网络效率 拓扑结构 

分 类 号：TN915.04[电子电信—通信与信息系统]