共查询到20条相似文献,搜索用时 109 毫秒
1.
2.
3.
4.
5.
6.
随着多媒体及实时应用的普及,在移动自组网中为业务流提供服务质量保证现已成为研究热点.提出一种在大规模移动自组网中提供服务质量保证的分段式路由协议.该协议采用直线逼近的方法,逐段建立满足带宽要求且延迟小的路径,并选择到源节点和目的节点连线距离最近的节点作为转发节点.通过分段、独立地维护路由,减小了路由维护的代价,提高了可扩展性.模拟结果表明该路由协议具有路由成功率高、路径短和延迟小等特点. 相似文献
7.
航空自组网是自组网在航空领域的典型应用.航空自组网的关键技术在于路由协议的选取和设计.基于场景用NS2软件仿真研究了3种适用于航空自组网的路由协议及其网络性能,并定义了4个性能评估准则.仿真结果表明,单跳距离一定时,3种路由协议的网络性能随着节点密度的增加而总体变差.同等条件下,AODV路由协议路由开销高于DSVD和GRID路由协议,端到端平均延时低于DSVD和GRID路由协议,而GRID协议分组投递率和平均跳数保持最高. 相似文献
8.
9.
10.
11.
Routing is one of the most basic networking functions in mobile ad hoc networks. Hence, an adversary can easily paralyze the operation of the network by attacking the routing protocol. This has been realized by many researchers and several "secure" routing protocols have been proposed for ad hoc networks. However, the security of those protocols has mainly been analyzed by informal means only. In this paper, we argue that flaws in ad hoc routing protocols can be very subtle, and we advocate a more systematic way of analysis. We propose a mathematical framework in which security can be precisely defined and routing protocols for mobile ad hoc networks can be proved to be secure in a rigorous manner. Our framework is tailored for on-demand source routing protocols, but the general principles are applicable to other types of protocols too. Our approach is based on the simulation paradigm, which has already been used extensively for the analysis of key establishment protocols, but, to the best of our knowledge, it has not been applied in the context of ad hoc routing so far. We also propose a new on-demand source routing protocol, called endairA, and we demonstrate the use of our framework by proving that it is secure in our model 相似文献
12.
Ad hoc networks have the notable capability of enabling spontaneous networks. These networks are self-initializing, self-configuring, and self-maintaining, even though the underlying topology is often continually changing. Because research has only begun to scratch the surface of the potential applications of this technology, it is important to prepare for the widespread use of these networks. In anticipation of their ubiquity, the protocols designed for these networks must be scalable. This includes scaling to both networks with many nodes, and networks with rapidly changing topologies. This paper presents two hierarchical clustering protocols that improve the scalability of ad hoc routing protocols. The Adaptive Routing using Clusters (ARC) protocol creates a one-level clustered hierarchy across an ad hoc network, while the Adaptive Routing using Clustered Hierarchies (ARCH) protocol creates a multi-level hierarchy which is able to dynamically adjust the depth of the hierarchy in response to the changing network topology. It is experimentally shown that these protocols, when coupled with an ad hoc routing protocol, produce throughput improvements of up to 80% over the ad hoc routing protocol alone. 相似文献
13.
Power-aware routing protocols in ad hoc wireless networks 总被引:5,自引:0,他引:5
An ad hoc wireless network has no fixed networking infrastructure. It consists of multiple, possibly mobile, nodes that maintain network connectivity through wireless communications. Such a network has practical applications in areas where it may not be economically practical or physically possible to provide a conventional networking infrastructure. The nodes in an ad hoc wireless network are typically powered by batteries with a limited energy supply. One of the most important and challenging issues in ad hoc wireless networks is how to conserve energy, maximizing the lifetime of its nodes and thus of the network itself. Since routing is an essential function in these networks, developing power-aware routing protocols for ad hoc wireless networks has been an intensive research area in recent years. As a result, many power-aware routing protocols have been proposed from a variety of perspectives. This article surveys the current state of power-aware routing protocols in ad hoc wireless networks. 相似文献
14.
在无线自组织网络中,由于节点移动,网络拓扑结构变化频繁,所以路由协议的选择一直都是关键问题。该文采用NS2软件对两种主要的协议:动态源路由协议(DSR)和自组网按需距离矢量路由协议(AODV)进行了仿真。并且通过端到端延时、路由开销和分组投递率三种参数在不同条件下的数据对两种协议进行了评估。实验结果表明没有一种协议能够完全适用于自组网,对于特殊环境选择不同协议以满足需要。 相似文献
15.
To efficiently support tetherless applications in ad hoc wireless mobile computing networks, a judicious ad hoc routing protocol is needed. Much research has been done on designing ad hoc routing protocols and some well-known protocols are also being implemented in practical situations. However; one major imperfection in existing protocols is that the time-varying nature of the wireless channels among the mobile-terminals is ignored; let alone exploited. This could be a severe design drawback because the varying channel quality can lead to very poor overall route quality in turn, resulting in low data throughput. Indeed, better performance could be achieved if a routing protocol dynamically changes the routes according to the channel conditions. In this paper, we first propose two channel adaptive routing protocols which work by using an adaptive channel coding and modulation scheme that allows a mobile terminal to dynamically adjust the data throughput via changing the amount of error protection incorporated. We then present a qualitative and quantitative comparison of the two classes of ad hoc routing protocols. Extensive simulation results indicate that channel adaptive ad hoc routing protocols are more efficient in that shorter delays and higher rates are achieved, at the expense of a higher overhead in route set-up and maintenance. 相似文献
16.
The strongest feature of ad hoc networks is its capability to be rapidly deployed anywhere and anytime without relying on
a pre-existing infrastructure. From there, ad hoc networks offer the advantages to be auto-organized, ubiquitous, dynamic
and completely autonomous. As a counter part, securing them becomes a more difficult task, especially because of the absence
of centralized entities in the network. Inevitably, the security problem presents currently a hot topic raising more and more
challenges within industrials and researchers, and many interesting securing solutions were meanwhile proposed, omitting however
to suit to ad hoc networks characteristics and therefore disadvantaging them. In this paper, we propose a securing scheme
for the OLSR routing protocol based on the secret sharing idea. We initially expose the general characteristics and the security
problems related to ad hoc routing protocols. We then address the security requirements of ad hoc routing protocols and the
security requirements we focus on. Finally, we define our completely and distributed securing algorithm based on threshold
cryptography. A primary main conception objective being to suit as much as possible to ad hoc networks characteristics by
avoiding as much as possible assumptions contradictory with the auto-organized and dynamic nature of ad hoc networks. Simulation
results depict the additional delay due to security enhancements. Results show that this delay stills suitable to OLSR routing
specifications. 相似文献
17.
Ad Hoc网络的安全问题和安全策略 总被引:8,自引:2,他引:6
AdHoc网络作为一种无线移动网络正成为网络研究,特别是军事研究的一个热点。由于AdHoc网络的特点,其安全问题和安全策略正受到越来越广播的重视。文中介绍了AdHoc网络的特点,论述了AdHoc网络和路由协议的安全问题,最后讨论并提出了AdHoc网络的一些安全策略。 相似文献
18.
《Mobile Computing, IEEE Transactions on》2007,6(4):463-479
Simulation and physical implementation are both valuable tools in evaluating ad hoc network routing protocols, but neither alone is sufficient. In this paper, we present the design and performance of PRAN, a new system for the physical implementation of ad hoc network routing protocols that unifies these two types of evaluation methodologies. PRAN (physical realization of ad hoc networks) allows existing simulation models of ad hoc network routing protocols to be used - without modification - to create a physical implementation of the same protocol. We have evaluated the simplicity and portability of our approach across multiple protocols and multiple operating systems through example implementations in PRAN of the DSR and AODV routing protocols in FreeBSD and Linux using the standard existing, unmodified ns-2 simulation model of each. We illustrate the ability of the resulting protocol implementations to handle real, demanding applications by describing a demonstration with this DSR implementation transmitting real-time video streams over a multihop mobile ad hoc network; the demonstration features mobile robots being remotely operated based on the real-time video stream transmitted from the robot over the network. We also present a detailed performance evaluation of PRAN to show the feasibility of our architecture 相似文献
19.
Chenn-Jung Huang Wei-Kuang Lai Sheng-Yu Hsiao Hao-Yu Liu Rui-Lin Luo 《International Journal of Wireless Information Networks》2004,11(3):131-146
In this paper, a routing protocol which utilizes the characteristics of Bluetooth technology is proposed for Bluetooth-based mobile ad hoc networks. The routing tables are maintained in the master devices and the routing zone radius for each table is adjusted dynamically by using evolving fuzzy neural networks. Observing there exists some useless routing packets which are helpless to build the routing path and increase the network loads in the existing ad hoc routing protocols, we selectively use multiple unicasts or one broadcast when the destination device is out of the routing zone radius coverage of the routing table. The simulation results show that the dynamic adjustment of the routing table size in each master device results in much less reply time of routing request, fewer request packets and useless packets compared with two representative protocols, Zone Routing Protocol and Dynamic Source Routing. 相似文献
20.
Efficient flooding with passive clustering-an overhead-free selective forward mechanism for ad hoc/sensor networks 总被引:8,自引:0,他引:8
Taek Jin Kwon Gerla M. Varma V.K. Barton M. Hsing T.R. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2003,91(8):1210-1220
High capacity real-time data communications in sensor networks usually require multihop routing and ad hoc routing protocols. Unfortunately, ad hoc routing protocols usually do not scale well and cannot handle dense situations efficiently. These two issues-scalability and density-are the major limitations when we apply ad hoc routing schemes to sensor networks. Passive clustering (PC) classifies ad hoc/sensor nodes into critical and noncritical nodes without any extra transmission. By 2-b piggybacking and monitoring user traffic (e.g., data polling requests from a sink), PC deploys the clustering structure "for free". Moreover, PC makes even the first flooding as efficient as all subsequent floodings (i.e., no initialization overhead). PC introduces many benefits, including efficient flooding and density adaptation. As a result, PC reduces control overhead of ad hoc routing protocols significantly and, as a consequence, enables ad hoc routing in large, dense sensor networks. The resulting structure can be utilized in cluster-based ad hoc network/sensor networking as well as for active node selection. 相似文献