Topology Management for Improving Routing and Network Performances in Mobile Ad Hoc Networks

A distributed topology management algorithm based on the construction of a forest from the topology of the network is proposed. In this algorithm, each tree of the forest forms a zone, and each zone is maintained proactively. As a result, the network can be seen as a set of non-overlapping zones. We introduce the concept of quality of connectivity for extracting the links connecting the pair of best nodes, and use this quality to construct the forest. We characterize the behaviors of the proposed topology management algorithm under various network density. We study the effect of the topology management on the performance of an ad hoc routing protocol. The results demonstrate that the performance of routing can be significantly improved with the help of topology management.     

移动Ad hoc网络基于链路质量和拓扑质量的路由协议

移动Ad hoc网络中节点的移动性使得频繁的路由失效与路由发现,路由发现中的控制开销是影响路由性能的一个重要的因素。传统的按需路由协议多采用洪泛的方式进行路由发现,并选取最小跳数路由。每个中间节点盲目的转发收到的路由请求包,不仅没有考虑链路质量,而且会引起广播风暴问题。本文提出一种基于链路质量和拓扑质量的路由协议,该协议根据相邻节点之间剩余链路生存期作为链路质量指标,同时根据中间节点与源-目的节点连线的距离关系作为拓扑质量指标。结合两个指标设置转发概率,不仅能避免频繁的路径断开,而且限制了路由请求包的传播范围。模拟结果显示,本文提出的方法在显著地降低路由控制开销的同时,还能够提高分组投递率并降低端到端延迟,从而提高了路由性能。     

自组网内的延迟限制QoS路由算法研究

介绍了自组网内的延迟限制 ＱｏＳ（Ｑｕａｌｉｔｙ－ｏｆ－Ｓｅｒｖｉｃｅ）路由算法，并对它进行了仿真。该算法可在网络状态信息不精确的情况下，同时并行寻找多条路径，以优化路径选择。当节点移动、离开、加入时，引入容错机制，以便于路径保持。通过仿真可以看出，该算法在适度的寻路代价下，可以得到较高的呼叫接收率。     

Ariadne: A Secure On-Demand Routing Protocol for Ad Hoc Networks

An ad hoc network is a group of wireless mobile computers (or nodes), in which individual nodes cooperate by forwarding packets for each other to allow nodes to communicate beyond direct wireless transmission range. Prior research in ad hoc networking has generally studied the routing problem in a non-adversarial setting, assuming a trusted environment. In this paper, we present attacks against routing in ad hoc networks, and we present the design and performance evaluation of a new secure on-demand ad hoc network routing protocol, called Ariadne. Ariadne prevents attackers or compromised nodes from tampering with uncompromised routes consisting of uncompromised nodes, and also prevents many types of Denial-of-Service attacks. In addition, Ariadne is efficient, using only highly efficient symmetric cryptographic primitives.     

移动Ad Hoc网络安全按需路由协议

Ad Hoc网络的安全性问题越来越引起人们的关注,如何确保Ad Hoc网络路由协议的安全成为Ad Hoc研究的一项关键技术。提出一种适用于移动Ad Hoc网络的安全按需源路由协议,利用移动节点之间的会话密钥和基于散列函数的消息鉴别码HMAC一起来验证路由发现和路由应答的有效性。提出的邻居节点维护机制通过把MAC地址和每个节点的ID绑定来防御各种复杂的攻击如虫洞攻击。NS-2仿真表明该协议能有效地探测和阻止针对Ad Hoc网络的大部分攻击。     

软件定义无人机自组网快速一致性更新机制

为了解决软件定义无人机自组网(Software-defined Unmanned Aerial Vehicle Ad Hoc Network, SDUANET)中转发黑洞和更新轮次问题,提出了一种软件定义无人机自组网快速一致性更新机制(Software-defined Unmanned Aerial Vehicle Ad Hoc Network Fast Consistent Update Mechanism, SDUANET-FCU)。新机制首先对节点进行分类操作,对可能会导致转发黑洞的发送操作进行约束;其次,针对含有两个规则的节点提出一种基于混合规则的两轮一致性更新策略;最后,将计算得出的Flow-mod发送顺序整合到两轮更新顺序中。仿真结果表明,在软件定义无人机自组网场景下,相比于现有的软件定义网络(Software Defined Network, SDN)更新方法,SDUANET-FCU降低了转发黑洞的概率和控制消息的数量,减少了平均更新轮次。     

无线adhoc网络中的多径源路由

本文针对无线ad hoc网络提出了一种基于DSR(动态源路由)的路由算法,多径源路由(MSR).MSR对DSR中的路由搜索和路由维护机制进行了扩展,用来解决多径路由问题.本文还提出,在多条路径之间基于测量的RTT进行负载分配.仿真结果表明,MSR在只增加少量网络开销的情况下,提高了TCP和UDP的投递率,降低了丢包率,并减少了端到端之间的延迟以及队列长度,从而有效地减少了网络拥塞.     

基于定位辅助和能量有效的超宽带网路由算法

文中在分析了超宽带（Ultra-Wideband，UWB）技术特点的基础上，与Ad Hoc网络已有的路由协议结合，提出了一种基于定位辅助和能量有效的超宽带自组网路由算法。仿真表明，该算法能够显著延长网络生存时间，均衡节点电量消耗。     

一种基于空洞节点检测的可靠无人机自组网路由协议

针对高动态无人机自组网中节点之间链路生存时间（Link Live Time,LLT）短和节点遭遇路由空洞次数多的问题,提出了一种基于空洞节点检测的可靠无人机自组网路由协议——GPSR-HND（Greedy Perimeter Stateless Routing Based on Hollow Node Detection）。GPSR-HND协议中,转发节点通过空洞节点检测机制检测邻居节点状态,将有效邻居节点加入待选邻居节点集;然后基于层次分析法（Analytic Hierarchy Process,AHP）的多度量下一跳节点选择机制从待选邻居节点集中选择权重最大的邻居节点贪婪转发数据;如果待选邻居节点集为空,则从空洞邻居节点集中选择权重最大的空洞节点启动改进的周边转发机制,寻找可恢复贪婪转发模式的节点。与GPSR-NS协议和GPSR协议相比,GPSR-HND协议表现出了更好的性能,包括平均端到端时延和丢包率的改善,以及吞吐量的提高。     

Scalable Routing Protocol for Ad Hoc Networks

In this paper we present a scalable routing protocol for ad hoc networks. The protocol is based on a geographic location management strategy that keeps the overhead of routing packets relatively small. Nodes are assigned home regions and all nodes within a home region know the approximate location of the registered nodes. As nodes travel, they send location update messages to their home regions and this information is used to route data packets. In this paper, we derive theoretical performance results for the protocol and prove that the control packet overhead scales linearly with node speed and as N ^3/2 with increasing number of nodes. These results indicate that our protocol is well suited to relatively large ad hoc networks where nodes travel at high speed. Finally, we use simulations to validate our analytical model.     

一种基于可靠性的车载自组织网络路由算法

提出了一种改进的GPSR路由算法.该算法在选择转发节点过程中同时考虑位置和方向,进而提高转发节点选择的正确性来增加通信链路可靠性.用VanetMobisim交通仿真软件构建真实的VANETs网络城市场景,结合NS-2进行仿真研究,结果表明,和传统GPSR算法相比,改进的GPSR路由算法在端到端时延影响不大的条件下,能够有效地提高数据包传递率,降低数据丢包率.因此,改进的GPSR协议更适用于对实时性要求不高、而对可靠性要求较高的VANETs网络.     

基于Ka/Ku相控阵天线的空基自组网协议设计

针对空基自组织网络的大容量通信需求,首先提出了基于频分复用的定向MAC协议,在邻居发现过程中将测距算法与多维尺度变换定位算法相结合得到每个节点的相对位置,并设计了双预约资源分配算法,完成定向数据传输;然后提出了定向路由协议,解决了次佳路由问题和路由应答风暴,并加入相邻搜索、链路质量评估和备用路由,降低了协议开销。空基自组网基于Ka/Ku相控阵天线的定向传播特性以及Ka/Ku频段频谱资源丰富的特点,使用频分复用、空分复用技术实现多个信道的高速并行传输,从而极大地提高网络的吞吐量。     

一种基于竞争转发的城市场景车载 Ad Hoc网络路由算法

 论文提出了一种适用于城市场景下的基于竞争转发的车载Ad hoc网络路由算法,算法摒弃了HELLO消息的使用,利用分布式的竞争策略根据邻居节点所处的地理位置信息进行下一跳节点的选择.数据转发使用选定点路由同时利用了实时的道路交通信息和网络拓扑结构信息进行选定点选择.采取暂存转发策略处理网络分割现象.仿真结果表明该算法比其他类似算法具有更高的数据包递交率和较低的数据延迟.     

AMRoute: Ad Hoc Multicast Routing Protocol

The Ad hoc Multicast Routing protocol (AMRoute) presents a novel approach for robust IP Multicast in mobile ad hoc networks by exploiting user-multicast trees and dynamic logical cores. It creates a bidirectional, shared tree for data distribution using only group senders and receivers as tree nodes. Unicast tunnels are used as tree links to connect neighbors on the user-multicast tree. Thus, AMRoute does not need to be supported by network nodes that are not interested/capable of multicast, and group state cost is incurred only by group senders and receivers. Also, the use of tunnels as tree links implies that tree structure does not need to change even in case of a dynamic network topology, which reduces the signaling traffic and packet loss. Thus AMRoute does not need to track network dynamics; the underlying unicast protocol is solely responsible for this function. AMRoute does not require a specific unicast routing protocol; therefore, it can operate seamlessly over separate domains with different unicast protocols. Certain tree nodes are designated by AMRoute as logical cores, and are responsible for initiating and managing the signaling component of AMRoute, such as detection of group members and tree setup. Logical cores differ significantly from those in CBT and PIM-SM, since they are not a central point for data distribution and can migrate dynamically among member nodes. Simulation results (using ns-2) demonstrate that AMRoute signaling traffic remains at relatively low level for typical group sizes. The results also indicate that group members receive a high proportion of data multicast by senders, even in the case of a highly dynamic network.     

移动自组网QoS路由协议研究

移动自组网是由一组带有无线收发装置的移动节点组成的一个多跳的临时性的自治系统。随着无线通信中多媒体业务的增加,在移动自组网中提供QoS(Quality of Sevice服务质量)保障具有越来越重要的意义,而QoS路由技术则是其中的核心技术和热点问题。文章指出移动自组网QoS路由的困难,对移动自组网典型QoS路由协议进行了详细的分析与比较,并对几种较新的移动自组网QoS路由协议进行了介绍,末了对移动自组网QoS路由协议的发展进行了展望。     

Ad Hoc网络组播路由ODMRP协议的改进

ODMRP组播协议非常适合于带宽限制大、移动性强和节点能量受限的Ad hoc网络.为了进一步提高该协议的性能,文中提出一种新的技术来增强其功效.增强ODMRP的主要目标有:(1)改进节点移动模式的适应性;(2)消除路由获得时延.最后仿真结果显示该改进协议比原协议在数据分发率和网络有效性等性能方面有很大改善.     

Channel Adaptive Shortest Path Routing for Ad Hoc Networks

1　IntroductionAdhocnetworksareformedwithoutrequiringthepreexistinginfrastructureorcentralizedadminis tration ,incontrasttocellularnetworks.Asidefromtheoriginalmilitaryapplication ,ithasapplicationinpublicsafetyandcommercialareas,butadaptiveprotocolsarerequiredinorderforthemtodoso .Twoimportantcharacteristicsofacommunicationlinkinadhocnetworksareitsunreliabilityanditsvariability .Thelinksinsuchanetworkareunreli ablebecauseoffading ,interference,noise,andper hapsthefailureofthetransmittingorrec…     

无线自组织网络路由协议的教学探索

本文借助NS2和NSG2软件,搭建了辅助无线自组织网络路由协议教学的平台,研究DSDV、DSR和AODV路由协议。本文通过NSG2软件生成TCL脚本文件,供NS2仿真使用,并生成nam文件和trace文件。nam文件可以演示路由协议的动态运行过程,trace文件可以分析路由协议的效果。这有利于学生掌握和理解"无线网络技术"课程中路由协议中的概念,提高教学质量和效果。     

一种基于迁移可测度的移动自组织网路由模型

 本文利用链路状态有效估测端到端路径的可达性。路由模型给出最近时间内,任意两点分组传输的迁移可测度;节点根据其邻节点的迁移可测度制定组合策略,计算组合迁移可测度,选取最优中继组合完成分组传输。仿真实验表明,该路由模型既可有效控制分组副本数目,又可获得较高的分组到达率。     

Estimating Hop Counts in Position Based Routing Schemes for Ad Hoc Networks

The recent availability of small, inexpensive low power GPS receivers and techniques for finding relative coordinates based on signal strengths, and the need for the design of power efficient and scalable networks, provided justification for applying position based routing methods in ad hoc networks. A number of such algorithms were developed recently. They are all based on three greedy schemes, applied when the forwarding node is able to advance the message toward destination. In this paper we show that the hop count, that is the number of transmissions needed to route a message from a source node to a destination node can be estimated reasonably accurately (in random unit graphs with uniform traffic), with less than 10%, 5% and 7% error for directional (compass), distance (greedy) and progress (MFR) based schemes, respectively, for 100 nodes with average degrees between 5 and 14, without experiments. Our results are derived from statistical observations regarding expected position of forwarding neighbor.