【作者】 张婷；

【导师】 沙毅；

【作者基本信息】 东北大学 ， 信号与信息处理， 2009， 硕士

【摘要】 Ad Hoc网络是由一组移动节点通过自组连接形成的多跳无线网络。该网络允许节点以任意速度和模型运动,这就要求路由协议必须有足够快的反应速度以跟得上节点移动所导致的网络拓扑结构的变化。传统的AODV路由协议选择最短路径传输数据,经常造成网络负载过分集中在某些节点,使数据包在这些过载节点的处理时延过长或者被丢弃,因此负载均衡问题的研究至关重要。提出一种基于动态指数平滑模型对网络流量负载进行预测的负载均衡路由协议DES-TPLBP (Dynamic Exponential Smoothing Model-Based An Ad Hoc Network Traffic Prediction Load Balancing Protocol)。该协议根据MAC层接口队列长度计算流量负载,同时将网络动态平均负载定义为阈值。在路由维护阶段利用动态指数平滑模型对节点的流量负载进行预测,根据预测到的下一时刻流量负载状况,在节点拥塞丢包之前,提前实施路由更新机制,以此提高网络性能,保证数据传输的可靠性。另外在路由发现阶段中间节点将自身的负载和阈值比较,根据比较结果有选择地转发RREQ分组,以阻止在重负载节点上建立路由；同时目的节点采用延时应答的方法选择轻负载路径回复应答分组,以实现均衡负载。在NS-2仿真平台上从三个不同的角度对DES-TPLBP、T-LBRP和AODV三种协议进行仿真和性能分析。结果表明：与传统AODV协议相比,T-LBRP协议将平均端到端时延最大降低约32%,路由开销改善18%,分组投递率上升8%。DES-TPLBP协议比T-LBRP协议有更好的网络性能,DES-TPLBP协议较AODV协议将端到端时延最大降低约37%,路由开销改善20%,并使分组投递率上升10.4%,即从整体上改善网络性能。更多还原

【Abstract】 Ad Hoc networks is a self-organizing, multi-hop networks composed of a group of node moving at any speed and with any motion model, which requires the routing protocol adapt to the change of network topology rapidly. The traditional AODV protocol uses the shortest path as their routing criteria, which results in routing load concentrating on just a few nodes. It leads to the discard or high transmission delay of the packet. So, it is important of the research on the load-balancing routing protocol.This thesis proposes a Dynamic Exponential Smoothing Model-Based Ad Hoc Network Traffic Prediction Load Balancing Protocol (DES-TPLBP). In the protocol, the traffic load according to the length of the interface queue of MAC layer is calculated and the dynamic average load of the network is defined as a threshold value. In the routing aegis stage, the nodes’ load state in the future can be determined earlier by DES-TPLBP. Then the forthcoming congestion can be prevented by the route-discovery mechanism and the transfer reliability can be improved. In addition, the load value of the intermediate node is compared with the threshold value during the routing discovery stage, then the RREQ groups are selectively transfered on the basis of the comparison results to prevent the routing construction on re-load node. Meanwhile, the network performance is also improved by the delay response of destination node to some extent.Simulation was done on NS2-based platform for comparing the properties of DES-TPLBP, T-LBR and AODV protocol through three different angles. Simulation results proved that, in comparison with the traditional protocol, T-LBRP reduces the average end-to-end delay and the the normalized routing overhead by 32% and 18% respectively, while raising the delivery ratio by 8%. The DES-TPLBP protocol perform better than T-LBRP protocol, it can reduce the end-to-end delay by approximately 50% and the normalized routing overhead by 28%, while raising the delivery ratio by 10.4%.更多还原