无线簇树网下的GTS时隙调度算法

研究了无线传感器网络簇树结构下的超帧调度机制,针对无线簇树网络中的通信冲突和暴露节点问题展开研究,提出了一套分析理论和判定准则,并在此基础上给出了一种基于区分服务的GTS统筹调度算法。利用NS2软件进行仿真实验,结果表明：算法能够充分利用信道,合理分配时隙,避免不必要的通信冲突,在提高吞吐率、减少丢包率和稳定网络时延方面都具有明显的效果。     

基于能量分布的异构传感器网络分簇算法

针对能量异构的无线传感器网络,提出一种分簇算法。该算法采用基于节点剩余能量分布状况的簇头竞争参数,降低成簇过程中的通信能耗,实现簇头的均匀分布。在簇间综合考虑簇头剩余能量及其与基站的通信能耗,以选择合适的下一跳路由节点。仿真结果表明,该算法可以均衡网络能量消耗,提高节点能量利用效率,延长网络寿命。     

无线传感器网络中分布式多跳路由算法研究

在对无线传感器网络路由算法深入研究的基础上,设计出了一种完全分布式的、能量有效的无线传感器网络多跳路由算法,主要内容包括:(1)在成簇方面,给出了一种基于时间延迟机制的无线传感器网络成簇算法CHTD,解决了相同能量节点在产生簇头时的碰撞问题。并通过仿真验证了CHTD成簇算法比LEACH和目前已有的基于定时器的成簇算法TB-LEACH对网络性能有明显改善;(2)在簇头数据传输方面,给出CHTD-M簇间多跳路由算法。该算法将网络中均匀分布的簇头构造成一棵路由树,通过多跳传输的方式减少直接与基站通信的簇头节点数量。最后对整体算法进行仿真,实验结果表明,CHTD-M把节约网络能量和保持网络负载平衡很好的结合起来,显著地延长了网络的生命周期。     

一种基于树均匀分簇的WSNs节能路由协议

针对无线传感器网络(WSNs)典型分簇LEACH算法簇首分布不均和簇首与基站一跳通信能耗大的问题,提出一种基于树均匀分簇的节能路由协议(EUCR).基于节点接收信号强度与自身剩余能量的乘积及网络连通度选取簇首,计算簇首间的合理距离,使网络均匀分簇;基于跳数与簇首当前剩余能量构造簇间优化路由树.在OMNeT++中对EUC...     

一种无线传感器网络中自主选择簇头的聚类算法

在无线传感网络中,传感器节点要定期向基站发送收集的数据。为了支持数据汇总,通过高效的网络组织将节点划分成若干簇。在这种类型的系统中,随着簇头的轮转,每个簇中的簇头选择方法是最具有挑战性的问题,有效的簇头选择算法可以提高网络的续航时间,并减少在WSN中的节点之间的通信开销。提出一个簇内民主方式选举算法来选择簇中的节点作为簇头,用MatLab对算法进行仿真,证明该算法的性能可以有效改善网络的性能。     

PTTC:无线传感网络分簇算法

分簇是延长无线传感网络寿命的有效技术。为此,提出了基于Prim的树簇拓扑的无线传感网络分簇PTTC算法。PTTC算法首先推导最优的簇数,再计算节点被选为簇头的平均概率。然后,结合节点的剩余能量以及被选为簇头的频率数选择簇头,最后利用Prim算法建立树,节点依据树传输数据,进而提高能量利用率,扩延网络寿命。仿真结果表明,提出的PTTC算法平衡了节点间的能量消耗,有效地延长了网络寿命。     

基于非均匀分环与最小通信代价的路由算法

为了提高无线传感器网络的生命周期,提出了一种基于非均匀分环与最小通信代价的路由算法URMC.算法采用圆环模型,首先为各环分配不同的簇头选择概率;其次以各环节点能耗均衡为目标,推导出各环宽度的表达式;最后通过设计通信代价公式来选择簇头和建立簇间路由树.最终形成一个节点能耗均衡、簇间路由合理的网络.经仿真验证,URMC算法能有效克服能量空洞现象,延长网络的生存周期.     

低冗余度WSN非均匀分簇算法应用研究

将传统非均匀分簇算法应用于低冗余度的无线传感器网络(WSN)中时,存在传感器节点早衰和簇间多跳通信传输能量开销不均衡的问题。为此,针对低冗余度WSN,提出基于粒子群和最短路由树的非均匀分簇路由算法。利用粒子群算法优化非均匀分簇过程,通过建立最短路由树搜索簇间多跳传输最优路径,实现数据从传感器节点到基站的高效传输。仿真结果表明,相比于EECS和EEUC算法,该算法可有效延长低冗余度WSN的网络生命时间,均衡簇间通信能量消耗。     

负载均衡感知的无线传感器网络容错分簇算法

好的分簇算法能够有效减少网络能耗和提高网络可靠性,但是簇间负载的不均衡性和通信的不可靠性会严重影响分簇算法的性能.针对这个问题,该文首先提出了一个负载均衡感知的无线传感器网络容错分簇算法.该方法引入了遗传算法的随机两点交叉算子和随机单点变异算子,从而设计了一种以种群粒子优劣为依据的自适应惯性权重调整策略,并提出了一种自适应的离散粒子群优化算法.算法设计同时考虑负载均衡和能量消耗两个优化目标,给出一种基于自适应离散粒子群优化的簇首选举机制;其次,为了保证网络上数据传输的可靠性,以最小生成树为基础,提出了一种用于保证簇首二连通性的簇间连通算法,通过消除网络中的割点,以保证网络的二连通性.仿真实验结果表明,该文提出算法在负载均衡和二连通性上有较好的性能,能有效减少了网络能耗,延长网络生命周期,并提高网络可靠性.     

一种基于能量均衡的无线传感器网络协议

无线传感器网络协议LEACH中提到了分簇的思想,能够有效的减少节点在通信中的能量消耗,延长网络的生存时间.为了更有效的减少节点的能量消耗,延长网络的生存时间,可以在分簇的算法中采用能量均衡的思想,同时簇头收集数据后通过一棵路由树向汇聚节点发送数据.实验表明采用基于能量均衡的分簇算法的无线传感器有更好的整体性能和网络生存时间.     

基于群树结构的IPv6无线传感器网络的组网及路由协议

如何实现WSN与IP网络的结合是当前的一个热点研究问题。针对IPv6与无线传感器网络相结合的标准全IP方式,研究了无线传感器网络的网络组织、路由以及地址分配方案,提出了基于群树结构的组网、路由以及地址分配方案,实现了IPv6与无线传感器网络的紧密结合,并用NS-2对其性能进行了仿真分析。     

End-to-end Delay Analysis for Mixed-criticality WirelessHART Networks

WirelessHART, as a robust and reliable wireless protocol, has been widely-used in industrial wireless sensoractuator networks. Its real-time performance has been extensively studied, but limited to the single criticality case. Many advanced applications have mixed-criticality communications, where different data flows come with different levels of importance or criticality. Hence, in this paper, we study the real-time mixedcriticality communication using WirelessHART protocol, and propose an end-to-end delay analysis approach based on fixed priority scheduling. To the best of our knowledge, this is the first work that introduces the concept of mixed-criticality into wireless sensor-actuator networks. Evaluation results show the effectiveness and efficacy of our approach.      

一种无线传感器网络的密钥管理方案

目前很多无线传感器网络的应用是建立在群组式通讯的模式之上,如何建立一个用以加密群组通讯的组密钥,来防范攻击者窃听无线传感器网络上的通讯,近年来引起广泛关注。为了在有限资源的无线传感器网络能安全进行群组通讯,本文只使用对称加密算法和单向哈希函数提出了一种具有有效性和扩充性的组密钥管理方案,并可满足前向和后向安全性。与目前现有的群组密钥相比,方案不仅具有较好的效率,并且更适合于无线传感器网络。     

TEASE: A novel Tunnel-based sEcure Authentication SchemE to support smooth handoff in IEEE 802.11 wireless networks

With the growing popularity of WiFi-based devices, WiFi-based wireless networks have received a great deal of interest in the wireless networks community. However, due to the limited transmission range of WiFi-based networks, mobile users have to switch their associated access points constantly to maintain continuing communications during their movement. The process of switching access points is called handoff. Handoff management is a key service in mobile networks, because providing seamless roaming in wireless networks is mandatory for supporting real-time applications in a mobile environment, such as VoIP, online games, and eConference. Security is another important issue in network communications, and to prevent possible attacks, authentication is required during the handoff process to guarantee the reliability of mobile clients and access points. In this paper, we propose a novel authentication scheme to achieve a smooth handoff in WiFi-based networks, which we refer to as TEASE. A tunnel is introduced to forward data packets between the new access point and the original reliable access point. The processing of a complete secure authentication and the transmitting of data between mobile terminals and their correspondence nodes can go on simultaneously. The security of handoff is achieved without increasing overhead to authentication servers, and handoff latency can be minimized to support seamless roaming. Simulation results show that our proposed scheme reduces significantly the communication interruption time and generates low packet loss ratio, and our method is suitable to be used for secure handoff in real-time applications.     

一种便携式消防救援通信箱系统的设计

在消防应急救援过程中,各种语音通信网络一般各自组网难以实现跨网通信,同时对应急现场和指挥中心的无线视频通信提出需求。结合COFDM无线视频通信技术和网络视频通信技术,利用IP交换机连接无线微波传输模块、异种网络语音互连通讯模块、网络视频传输模块,并放置在一个便携式箱体中,实现了异种网络语音互连以及无线远距离视频通信功能,保障了消防救援现场和指挥中心的音视频通信。     

无线HART网络点到点图路由的研究与实现

无线HART是一个开放的用于工业测量和控制的无线通信标准。无线HART标准在网络层采用图路由机制,通过提供链路冗余,以满足工业应用中安全、可靠的通信需求。现有的图路由算法研究仅局限于集中式通信,文中设计并实现了局部分布式通信的点到点图路由算法。该算法利用跳数、链路质量作为度量进行选路,提供跳间冗余以保证路由健壮性,并通过对跳间链路数的限定以及路由图范围的集中,可以为网络中任意两点间建立会话,减少控制时延,有效避免通信资源的浪费。该算法实现的通信模式不仅保留了集中式图路由的可靠性,也可以满足无线工业控制的灵活性和实时性需求。     

基于探测的多信道无线网状网机会路由算法

多信道无线网状网的性能在很大程度上依赖于信道分配和路由选择.现有的多信道无线网状网路由大多没有考虑信道之间的干扰问题,从而导致通信性能下降.针对这一问题,提出一种基于探测的多信道无线网状网机会路由(POR)算法.首先,根据干扰能量,选出最佳通信信道集来降低信道间的传榆干扰.在此基础上,采用探测方式计算路径期望传输时延,确定候选链路集并运用机会路由机制进行数据传输以最小化端到端的传输时延.实验结果表明,POR可以显著地降低平均端到端时延,提高数据包投递率,为数据传输提供实时性和可靠性保证.     

无线传感器网络的安全机制

近年来，随着微电子技术和无线通信技术的进步，推动了低功耗、低价格、多功能传感器的快速发展，进而也促进了无线传感器网络的发展．无线传感器网络在军事、医疗、商业等多个领域均有广阔的应用市场．针对无线传感器网络的特点，本文主要阐述它在通信过程中存在的安全威胁、分析它的安全需求和采取的安全机制，确保无线通信的安全．     

Automated wireless video surveillance: an evaluation framework

In the past years, surveillance systems have attracted both industries and researchers due to its importance for security. Automated Video Surveillance (AVS) systems are established to automatically monitor objects in real-time. Employing wireless communication in an AVS system is an attractive solution due to its convenient installation and configuration. Unfortunately, wireless communication, in general, has limited bandwidth, not to mention the intrinsic dynamic conditions of the network (e.g., collision and congestion). Many solutions have been proposed in the literature to solve the bandwidth allocation problem in wireless networks, but much less work is done to design evaluation frameworks for such solutions. This paper targets the demand for a realistic wireless AVS system simulation framework that models and simulates most of the details in a typical wireless AVS framework. The proposed simulation framework is built over the well-known NS-3 network simulator. This framework also supports the testing and the evaluation of cross-layer solutions that manages many factors over different layers of AVS systems in the wireless 802.11 infrastructure network. Moreover, the simulation framework supports the collection of many used performance metrics that are usually used in AVS system performance evaluation.     

Markov Chain-based performance analysis of multihop IEEE 802.15.4 wireless networks

In this paper, we propose a Markov chain-based analytical framework for modeling the behavior of the medium access control (MAC) protocol in IEEE 802.15.4 wireless networks. Two scenarios are of interest. First, we consider networks where the (sensor) nodes communicate directly to the network coordinator (the final sink). Then, we consider cluster-tree (CT) scenarios where the sources communicate to the coordinator through a series of intermediate relay, which forward the received packets and do not generate traffic on their own. In both scenarios, no acknowledgment messages are used to confirm successful data packet deliveries and communications are beaconed (i.e., they rely on synchronization packets denoted as “beacons”). In all cases, our focus is on networks where the sources and the relays have finite queues (denoted as buffers) to store data packets. The network performance is evaluated in terms of aggregate network throughput and packet delivery delay. The performance predicted by the proposed analytical framework is in very good agreement with realistic ns-2 simulation results.