Ad hoc网络中继协作机制的博弈分析

针对Ad Hoc网络中的多跳通信需要自私节点间的数据分组中继,不使用协作的激励机制,提出了一种基于博弈论的解决方案。该方案通过建立节点间中继协作的无限次重复博弈模型,给出此博弈的纳什均衡中继策略TFT,并对其群体稳定性进行了分析。通过仿真表明,各节点根据网络拓扑结构变化速度的快慢调整TFT策略的宽容因子g,能够有效激励节点间的中继协作。     

一种有效的分布式节能广播算法及性能分析

给出了有效的应用于无线Ad Hoc网络的分布式节能广播算法。在确定转播结点时,该算法让那些拥有较多未覆盖邻结点和较大新增覆盖面积的结点进行转播,选取尽可能少的邻结点为转播结点,以减小广播分组在网络中的重复。所提广播算法的分布式设计解决了其他节能广播算法中存在的开销太大的问题,使其更加适用于无线Ad Hoc网络的特殊环境。通过大量的仿真对广播算法的性能进行分析,结果表明与其他算法相比,所提算法能够大幅降低转播冗余、有效增加网络寿命。     

TDMA体制下的移动自组织网时隙同步方法

在TDMA体制下的移动网状自组织网络中,为了解决网络时隙同步问题,提出了一种不依赖GPS授时的网络时隙互同步算法。各节点通过计算相邻节点的时隙偏差,通过加权计算并调整本节点的时隙位置,使网内各节点的时隙起始都调整到同一位置上,达到时隙的互同步。通过仿真和实验,分析并验证了移动自组织网络时隙互同步的收敛性能和抗干扰性能。     

基于双线性对的Ad hoc网络主动秘密共享方案

针对现有的基于双线性对的安全机制都假设在整个Ad hoc网络生存期内系统都是安全的,而基于该假设的Ad hoc网络并不安全的问题。重新定义了Ad hoc网络的攻击者模型,对传统的主动秘密共享方案进行了扩充,提出了基于双线性对的Ad hoc网络主动秘密共享方案,周期性地更新系统私钥的影子和网络节点的私钥,以提高网络安全机制的安全性和鲁棒性,并对其安全性和鲁棒性进行证明。结论表明,基于双线性对的密码体制非常适合建立实用的、轻量级的Ad hoc网络的安全机制。     

Ad hoc distributed mutual exclusion algorithm based on token-asking

The solution of distributed mutual exclusion is difficult in Ad hoc networks owing to dynamic topologies and mobility. Based on the analysis of the properties of Ad hoc networks and the disadvantages of the traditional algorithms, an improved Ad hoc system model was given and a novel algorithm was presented as AHDME (Ad Hoc Distributed Mutual Exclusion); it was based on the token-asking algorithms. It utilized broadcast to search for the token and to decrease the message complexity of multi-hop Ad hoc networks. Lamport's timestamp was improved to ensure the time sequence and to prevent nodes from starvation. When compared to traditional algorithms, AHDME does not require the fixed size of request queues and the global system information, which adapts itself to the frequent arrival/departures and the limited computing capability of nodes in Ad hoc networks. Performance analysis and simulation results show that the AHDME algorithm has low message complexity, small space complexity, and short response delay.     

一种基于辅助路由的拥塞自适应协议

针对现有多跳无线自组网路由协议以被动方式对拥塞进行处理,有可能导致更多的分组丢失、更长的时延和更大的网络开销问题,提出了一种基于辅助路由的拥塞自适应协议（congestion adaptive protocol based on aided-routing, CAPAR）。该协议以主动方式对拥塞进行处理,采取建立辅助路由的方法对发送给拥塞节点的业务流量进行分流,主动避免拥塞的发生,克服了以被动方式对拥塞进行处理所带来的不利影响。给出了CAPAR协议的建立过程,证明了CAPAR协议的正确性,并对其路由存储代价和路由更新代价进行了分析。结果表明,与其他按需路由协议相比,CAPAR减少了重新建立路由所带来的开销和时延,其路由更新代价明显降低。     

一种新的Ad Hoc分簇算法及其性能仿真

Ad Hoc网络是一种多跳的自组织网络,网络是由移动的节点组成。Ad Hoc网络的许多应用都依赖层次结构的支持,簇结构是Ad Hoc网络中应用最为广泛的层次结构,而这种层次结构的形成和维护依赖于某种分簇算法。提出了移动节点的平均连接度和能量状态的计算方法,并在此基础上提出了一种新的基于权值的分簇算法(NWBCA),通过对算法进行分析和仿真测试,证明了该算法的有效性。     

一种Ad Hoc网络信道接入排队退避公平算法

移动Ad hoc网络是一种特殊的无固定控制中心的多跳网络。由于其特殊性，传统的CSMA协议直接应用在Ad hoc网络中会带来隐终端、暴露终端和公平性问题。本文基于Ad hoc网络信道接入层已有退避算法，提出了一种新型排队退避公平算法。分析与仿真结果表明，与IEEE802．11标准的BEB算法和其它算法相比，本文算法更为简单实用，且对于合适的参数取值，本文算法能有效地改善信道接入的不公平性，并能在信道吞吐量的下降和信道接入公平性的改善之间达到一个较好的折衷。     

Ad Hoc网络中一种基于邻节点活跃度的自适应退避算法

基于无线AdHoc网络中信道共享的特性,通常采用具有退避机制的MAC接入协议。由于网络节点的各邻居节点在前一段时间的活跃状态在一定程度上反映了网络的繁忙状况,活跃的邻居节点越多,表示信道竞争越激烈,网络越繁忙,反之网络比较空闲。据此,提出了一种基于邻居节点活跃状态的时延退避算法,根据邻居节点活跃数量自适应地调整时延退避窗口,从而提高了网络吞吐率。     

一种Ad Hoc网络信道接入退避算法及仿真分析

移动自组网络的应用环境以及其在商业上的潜在应用要求它支持QoS，高效合理的MAC协议对于保障Ad Hoc网络QoS具有重要的意义。在分析现有典型MAC协议及退避算法的基础上，提出了一种支特动态服务区分兼顾公平性的退避算法——服务区分动态退避（SDDB）算法。分析和仿真结果证明，与IEEE802．11等协议采用的退避算法相比，该算法在信道公平性和提供服务区分方面有较好的改善，并且在信道的吞吐量和提供服务区分、改善信道接入公平性之间能达到较好的折衷。     

Performance analysis of mobile ad hoc networks under flooding attacks

Due to their characteristics of dynamic topology, wireless channels and limited resources, mobile ad hoc networks are particularly vulnerable to a denial of service (DoS) attacks launched by intruders. The effects of flooding attacks in network simulation 2 (NS2) and measured performance parameters are investigated, including packet loss ratio, average delay, throughput and average number of hops under different numbers of attack nodes, flooding frequency, network bandwidth and network size. Simulation results show that with the increase of the flooding frequency and the number of attack nodes, network performance sharply drops. But when the frequency of flooding attacks or the number of attack nodes is greater than a certain value, performance degradation tends to a stable value.     

QoS-aware multicast routing protocol for Ad hoc networks

1 .INTRODUCTIONA mobile ad hoc network ( MANET) is a multi-hopwireless network formed by a collection of mobilenodes without the intervention of fixedinfrastructure.Because an Ad hoc network is infrastructure-less andself-organized,it is used to provide i mpromptu com-munication facilities in harsh environments . Typicalapplication areas of mobile ad hoc networkinclude bat-tlefields ,emergency search,rescue sites and data ac-quisitionin remote areas . A mobile Ad hoc networkisalso usef…     

战术移动Ad hoc网络仿真中移动模型研究

移动Ad hoc网络仿真中，节点移动模型的选取是否合适对于仿真非常重要，它直接影响到能否正确评价各层技术方案对动态拓扑的适应性。通过对现有移动Ad hoc网络移动模型的研究比较，针对战术移动Ad hoc网络结构特点，归纳出战术移动Ad hoc网络中节点移动特征，提出并建立了战术移动Ad hoc网络移动模型。通过仿真比较得出，建立的移动模型符合战术移动Ad hoc网络作战想定，适合战术移动Ad hoc网络仿真。     

Reliable adaptive multicast protocol in wireless Ad hoc networks

1.INTRODUCTIONA wireless ad hoc networkis a multi-hop wireless net-workformed by a collection of mobile nodes withoutthe intervention of fixed infrastructure.Because awireless ad hoc networkis infrastructureless and self-organized,it is used to provide i mpromptu communi-cationfacilities in harsh environments.Typical appli-cation areas of wireless ad hoc networkinclude battle-fields,emergency search,rescue sites and data acqui-sitionin remote areas.A wireless ad-hoc network isalso useful …     

Virtual reality mobility model for wireless ad hoc networks

For wireless ad hoc networks simulation, node＇s mobility pattern and traffic pattern are two key elements. A new simulation model is presented based on the virtual reality collision detection algorithm in obstacle environment, and the model uses the path planning method to avoid obstacles and to compute the node＇s moving path. Obstacles also affect node＇s signal propagation. Considering these factors, this study implements the mobility model for wireless ad hoc networks. Simulation results show that the model has a significant impact on the performance of protocols.     

采用平均加权的ad hoc网络分布式时隙同步算法

为了降低现有ad hoc网络分布式时隙同步算法复杂度,基于研究多个体系统行为特征的Vicsek模型,提出一种采用平均加权的分布式时隙同步算法。各节点通过计算自身及其邻节点时隙起始时刻的算术平均调整时隙位置,最终达到所有节点时隙位置的统一,实现全网同步。对算法在不同网络连接下的收敛性进行逐一分析,并对网络节点随机分布时的算法收敛性进行仿真,结果表明,算法适用于各种连通性网络且收敛速度较快。     

Distributed intrusion detection for mobile ad hoc networks

Mobile ad hoc networking(MANET)has become an exciting and important technology in recent years,because of the rapid proliferation of wireless devices.Mobile ad hoc networks is highly vulnerable to attacks due to the open medium,dynamically changing network topology,cooperative algorithms,and lack of centralized monitoring and management point.The traditional way of protecting networks with firewalls and encryption software is no longer sufficient and effective for those features.A distributed intrusion detection approach based on timed automata is given.A cluster-based detection scheme is presented,where periodically a node is elected as the monitor node for a cluster.These monitor nodes can not only make local intrusion detection decisions,but also cooperatively take part in global intrusion detection.And then the timed automata is constructed by the way of manually abstracting the correct behaviours of the node according to the routing protocol of dynamic source routing(DSR).The monitor nodes can verify the behaviour of every nodes by timed automata,and validly detect real-time attacks without signatures of intrusion or trained data.Compared with the architecture where each node is its own IDS agent,the approach is much more efficient while maintaining the same level of effectiveness.Finally,the intrusion detection method is evaluated through simulation experiments.     

Distributed intrusion detection for mobile ad hoc networks

Mobile ad hoc networking （MANET） has become an exciting and important technology in recent years, because of the rapid proliferation of wireless devices. Mobile ad hoc networks is highly vulnerable to attacks due to the open medium, dynamically changing network topology, cooperative algorithms, and lack of centralized monitoring and management point. The traditional way of protecting networks with firewalls and encryption software is no longer sufficient and effective for those features. A distributed intrusion detection approach based on timed automata is given. A cluster-based detection scheme is presented, where periodically a node is elected as the monitor node for a cluster. These monitor nodes can not only make local intrusion detection decisions, but also cooperatively take part in global intrusion detection. And then the timed automata is constructed by the way of manually abstracting the correct behaviours of the node according to the routing protocol of dynamic source routing （DSR）. The monitor nodes can verify the behaviour of every nodes by timed automata, and validly detect real-time attacks without signatures of intrusion or trained data. Compared with the architecture where each node is its own IDS agent, the approach is much more efficient while maintaining the same level of effectiveness. Finally, the intrusion detection method is evaluated through simulation experiments.     

Escape probability based routing for ad hoc networks

1. INTRODUCTION Mobile ad hoc networks are wireless multi-hop networks where mobile nodes are self-organized, have highly dynamic topology, limited bandwidth and no support of fixed infrastructure[1]. These characteristics often cause ad hoc networks to be viewed as quite different from traditional networks. Routing a packet from a source to a destination in an ad hoc network is a challenging problem. The main source of the challenge comes from the fact that there are no base stations in …     

A distributed adaptive multi-hop certification authority schemefor mobile Ad Hoc networks

1.INTRODUCTION Amobileadhocnetwork(MANET)isanau tonomoussystemofmobilenodesconnectedbywire lesslinks,theunionofwhichformsacommunication networkmodeledintheformofanarbitrarycommu nicationgraph[1].Thesalientfeaturesofadhocnet worksposechallengesinachievingsecuritygoals.In wirednetworks,anadversarycannotattacknetworks untilitconnectswiredphysicallink.Bycontrary,an attackinwirelessnetworksmaycomefromanyloca tion.Thereforeadhocnetworksmustadoptdis tributedcertificationauthority(CA),otherwis…