Distributed Flow Admission Control for Multimedia Services Over Wireless Ad Hoc Networks

In this paper we propose a novel Priority-based Distributed flow Admission Control (PDAC) protocol to provide Quality of Service (QoS) to multimedia applications over the Dynamic Source Routing (DSR) protocol-based wireless ad hoc networks. In contrast to short-term packet forwarding, medium and long-term multimedia and real-time traffic may benefit from ‘flow’-based transmission due to the reduction in the packet-level control overhead. In this paper, we introduce a new DSR option called the “Admission Control Option” for flow establishment, and present a new scalable transmission rate reservation protocol to support bandwidth-constrained traffic flows in interference-limited wireless ad hoc networks. It allows a node in the wireless ad hoc network to establish or discard a traffic flow state based on the global knowledge of traffic flow priority, and local knowledge in the form of interference and effective transmission rate. The PDAC scheme can also operate in a ‘cross-layer’ protocol architecture that encompasses the network layer and the MAC layer.     

无线Ad Hoc网络DSR路由协议的优化设计

按需路由协议动态源路由（DSR）是Ad Hoc网络路由协议中性能较优的一种,但对快速变化的移动网络拓扑结构反应较慢,造成过多地启动不必要的路由发现过程以及数据包发送路径绕远,从而导致效率降低。该文针对这一问题,对DSR协议进行优化,提出节点局部自适应机制,对于路由断路绕远等问题进行自动恢复调整。给出局部自适应DSR路由协议LSDSR,优化后的协议减少了路由发现次数和传输时延,更适用于实时业务。     

无线Mesh网络中的一种基于博弈论的DSR路由优化算法

无线Mesh网络(Wireless Mesh Network,WMN)是一种新型的高容量、高速率的分布式宽带无线网络。综合考虑了时延、传输拥塞、网络吞吐量等多方面因素,将博弈论的思想引入动态源路由协议(dynam-ic source routing,DSR)中,作为路由选择的依据,提出了一种基于博弈论的DSR路由优化协议,分析与仿真表明,该路由能有效地减小时延,提高数据传输效率。     

Nature Inspired Improved Firefly Algorithm for Node Clustering in WSNs

Wireless Sensor Networks (WSNs) comprises low power devices that are randomly distributed in a geographically isolated region. The energy consumption of nodes is an essential factor to be considered. Therefore, an improved energy management technique is designed in this investigation to reduce its consumption and to enhance the network’s lifetime. This can be attained by balancing energy clusters using a meta-heuristic Firefly algorithm model for network communication. This improved technique is based on the cluster head selection technique with measurement of the tour length of fireflies. Time Division Multiple Access (TDMA) scheduler is also improved with the characteristics/behavior of fireflies and also executed. At last, the development approach shows the progression of the network lifetime, the total number of selected Cluster Heads(CH), the energy consumed by nodes, and the number of packets transmitted. This approach is compared with Ad hoc On-Demand Distance Vector (AODV), Dynamic Source Routing (DSR) and Low Energy Adaptive Clustering Hierarchy (LEAH) protocols. Simulation is performed in MATLAB with the numerical outcomes showing the efficiency of the proposed approach. The energy consumption of sensor nodes is reduced by about 50% and increases the lifetime of nodes by 78% more than AODV, DSR and LEACH protocols. The parameters such as cluster formation, end to end delay, percentage of nodesalive and packet delivery ratio, are also evaluated... The anticipated method shows better trade-off in contrast to existing techniques.     

基于Ad hoc的按需路由协议DSR的优化研究与实现

无线Ad hoc网络是一种不需要基础设施的自组织和自管理网络,网络中所有的节点同时具有终端和路由器的功能。因此网络可以通过节点路由发现机制转发分组,并进行路由维护。文中对DSR(动态源路由协议)的路由发现过程进行了优化,并采用OPNET仿真软件对基于DSR协议的Ad hoc网络的路由开销和时延等关键参数进行了仿真统计,分析了改进后的路由协议对网络质量的影响。     

Analysis of MANET dynamic source routing and its performance enhancements

Since the inception of the dynamic source routing (DSR) protocol for mobile ad hoc networks, several enhancements have been proposed, along with other competing routing protocols. All of them provide different degrees of throughput improvement under different scenarios. In this paper, we use DSR as a base, diagnose the contribution of its constituent components, and provide the reason why certain routing enhancements can increase the throughput and under what conditions. A major finding of the study is that the broadcast mechanism used in propagating route request and route error messages has a significant impact on how routing behaves. We also show that unicast route error report and preventive cache update improve throughput at different sides of the mobility spectrum. Finally, we show that aggressive buffer combined with route management provides the best performance improvement on the entire mobility and loading spectrum. Copyright © 2013 John Wiley & Sons, Ltd.     

移动自组网路由协议DSR性能评价

研究移动自组网的难点之一是开发能够跟随网络拓扑变化,在移动节点之间快速找到有效路径的路由协议。DSR协议作为一种简洁有效的按需机制路由协议,成为IETF的MANET工作组提出的草案之一。本文利用MANET工作小组推荐的Ns2仿真软件对DSR进行模拟,从源节点个数、分组发送频率、移动速度、节点密度、节点个数五个方面分析DSR的性能,指出对DSR性能影响最大的因素。分析随分组频率降低协议性能下降是由于它的路径缓存策略引起,提出将针对DSR路径缓存,搜索,抛弃策略进行改进。     

自动抄表系统的无线网状网络设计

介绍基于无线网状网络的自动抄表系统的结构和工作原理;简要介绍中心节点集中器和无线数传模块的硬件设计;详细介绍该无线网状网络采用的改进的动态源路由协议(DSR),给出网络节点通信程序流程;并阐述了该网络通信参考模型中的各层通信协议。     

Ad Hoc路由协议在两种节点配置模型下的性能分析

对无线传感器网络中存在的两种节点配置模型,随机节点配置模型和四连通全覆盖优化节点配置模型进行性能分析.根据通信半径(表示为rc)和感知半径(表示为rs)的不同比率,提出一种新的仿真方法,并对这两种配置模型在不同Ad Hoc路由协议下的性能进行分析.大量的实验结果表明,四连通全覆盖优化节点配置模型不仅能减少配置成本和通信开销,而且对于不同的网络拓扑,其覆盖度、连通度和多个网络性能指标都有较大的提高.     

一种改进的动态源路由协议研究

原有的权值簇生成算法及其改进都未能很好解决节点移动性问题。针对这一点在一种新的改进权值簇生成算法基础上,提出了新的基于簇的动态源路由协议NCDSR（New Clustered Dynamic Source Routing）。该权值簇生成算法克服了原有算法的在处理节点的移动速度上的缺陷,在计算权重、生成簇头时,对节点的绝对移动速度进行了判断和限定。NCDSR在GloMoSim模拟器下定义了数据结构,进行了模拟仿真,实验证明当节点的绝对移动速度超过限定值时,NCDSR协议端到端延迟、吞吐率和投递率等性能在网络中载的情况下是可以接收的,较原有的动态源路由协议有效。