Effects of denial of service attack in mobile ad hoc networks

Mobile ad hoc networks are often deployed in environments where the nodes of the networks are unattended and have little or no physical protection against tampering. The nodes of mobile ad hoc networks are thus susceptible to compromise. The networks are particularly vulnerable to denial of service (DoS) attacks launched through compromised nodes or intruders. In this paper, we investigated the effects of flooding attacks in network simulation 2 (NS-2) and measured the packet delivery ratio and packet delay under different flooding frequencies and different numbers of attack nodes. Simulation results show that with the increase the flooding frequencies and the numbers of attack nodes, network performance drops. But when the frequency of flooding attacks is greater than a value, the performance decrease gets smooth. Meanwhile the packet delay firstly increases and then declines to a value of stability at the end.     

An range-free localization scheme for large scale underwater wireless sensor networks

In this paper, we study an area localization problem in large scale underwater wireless sensor networks (UWSNs). The limited bandwidth, the severely impaired channel and the cost of underwater equipment all make the underwater localization problem very challenging. Exact localization is very difficult for UWSNs in deep underwater environment. We propose a range free method based on mobile detachable elevator transceiver (DET) and 3D multi-power area localization scheme (3D-MALS) to address the challenging problem. In the proposed scheme, the ideas of 2D multi-power area localization scheme (2D-ALS) and utilizing DET are used to achieve the simplicity, location accuracy, scalability and low cost performances. The DET can rise and get down to broadcast its position. And it is assumed that all the underwater nodes underwater have pressure sensors and know their z coordinates. We evaluate the performances of 2D-ALS and our proposed 3D-MALS schemes under both ideal and non-ideal channel propagation conditions, in terms of localization error and localization ratio. The simulation results show that our proposed scheme is much more efficient than the 2D-ALS.     

A more efficient group key distribution scheme for wireless ad hoc networks

As the wireless medium is characterized by its lossy nature, reliable communication cannot be as-sumed in the key management scheme. Therefore self-healing is a good property for key distribution scheme in wireless applications. A new self-healing key distribution scheme was proposed, which is optimal in terms of user memory storage and efficient in terms of communication complexity.     

移动无线传感网络中基于Sink协助的数据采集算法

近年来,基于移动Sink协助的数据采集算法得到广泛关注并发展成为研究热点,本文综述了该领域国内外的研究进展,按照Sink移动模型的不同,分类讨论移动无线传感网络中,基于Sink协助数据采集的理论和算法．最后提出当前亟待解决的问题,并对发展趋势进行展望．     

基于抗局部攻击的无线传感器网络定位方法

为了解决无线传感器网络定位过程中的常见安全问题,提出了一种抗攻击的定位方法.该方法通过高效的认证机制和检测机制帮助待定位节点验证信标节点的合法性及检测定位信息的可靠性,筛选出值得信赖的定位信息用于节点的定位计算,能够有效抵御定位过程中的女巫攻击和虫洞攻击.实验结果验证了该方法能够在存在安全威胁的网络环境下,有效提高无线传感器节点的定位精度.     

介入移动汇聚节点的无线传感器网络高效数据收集方法

引入移动汇聚节点解决无线传感器网络高效数据收集问题.网络中固定汇聚节点与移动汇聚节点共存,全部传感器节点都拥有维护到固定汇聚节点的路由,移动汇聚节点进入网络后定期向其附近小范围内的传感器节点扩散自己的声明信息,传感器节点向距自己跳数最小的汇聚节点发送或转发数据包.移动汇聚节点和距离其一跳的传感器节点之间通过有效的应答机制来保证数据的可靠传输.通过仿真结果显示引入移动汇聚节点的数据收集在节省能耗方面明显优于传统网络.在延长网络生存时间的同时,可以获得较高的数据传输成功率和较短的数据传输延迟.     

基于博弈的无线Mesh网络高效可靠路由算法

由于无线网络节点自身资源有限,末端节点往往会表现出自私行为以保证其生存时间和工作效率.针对这些特点提出了一种基于博弈的能量容忍策略（ETS）模型,该模型在经典针锋相对（TFT）策略的基础上,加入合作度及能量容忍因子,宽容节点一定程度的自私行为,并给予自私节点改过自新的机会,使其能够恢复合作.同时,基于ETS设计一种路由激励机制,通过奖惩激励自私节点放弃自私行为,并对能量相对较低的节点进行保护,在一定程度上避免个别繁忙节点过度消耗,均衡网络能量,延长了网络的运行时间.实验表明ETS激励机制在防止节点自私行为、优化网络吞吐率和网络生存时间方面等表现出较好的性能优势.     

A new self-localization method for wireless sensor networks

Many applications of wireless sensor networks can benefit from fine-grained localization. In this paper, we proposed an accurate, distributed localization method based on the time difference between radio signal and sound wave. In a trilateration, each node adaptively chooses a neighborhood of sensors and updates its position estimate with trilateration, and then passes this update to neighboring sensors. Application examples demonstrate that the proposed method is more robust and accurate in localizing node than the previous proposals and it can achieve comparable results using much fewer anchor nodes than the previous methods.     

Effect of interference on transmission for newly deployed wireless sensor networks

The co-channel interference （collisions） seriously affect the transmission for the newly deployed wireless sensor networks since there is no structure at that phase. In this paper, the interference of the whole network is analyzed based on the SNIR model. The new concept of critical transmitting range is proposed, based on which the transmission theorem is obtained and proved. The results provide the theoretical ground to set up the primary structure of newly deployed networks.     

无线多媒体传感器网络的QoS路由算法

作为一种全新的信息获取和处理技术,无线多媒体传感器网络较之传统传感器网络更多地关注于音频、视频、图像等大数据量、大信息量媒体的采集与处理,在军事、民用及商业领域中具有广阔的应用前景.文中针对具有Mesh结构的无线多媒体传感器网络,给出了其带宽、时延和时延抖动等多约束的QoS路由问题模型的描述.基于基本遗传算法提出了一种多约束的QoS路由算法,给出了算法的具体实现流程,并对算法的收敛性和路由成功率等进行了实验仿真.     

无线传感器网络多路径路由算法的研究

在多路径路由算法的研究中,仍然存在着一定的局限性,如没有充分考虑网络中链路的多重特性.因此,文中在定向扩散路由算法的基础上提出了一种多路径路由算法(EDB-MRA).该算法在源节点和目的节点之间建立多条路径,根据网络链路中的3个特征值--能量消耗、延时和带宽,给每条路径赋予一定的选择概率,使得数据总能在链路性能较优的多路径中传输,从而延长了网络的生存周期,提高了传输的可靠性.     

Improved algorithm for distributed localization in wireless sensor networks

Many sensor network applications require location awareness,but it is often too expensive to equip a global positioning system(GPS) receiver for each network node.Hence,localization schemes for sensor networks typically use a small number of seed nodes that know their locations and protocols whereby other nodes estimate their locations from the messages they receive.For the inherent shortcomings of general particle filter(the sequential Monte Carlo method) this paper introduces particle swarm optimization a...     

无线多媒体传感器网络QoS路由博弈算法

由于传感器网络节点采用电池供电,单个节点能量的过度消耗会导致网络的失效,因此传感器节点可能因为能量限制而拒绝转发数据.正是因为传感器节点存在这种潜在的自私行为,传感器网络路由问题可以描述为一个减少节点能量消耗而获得最大网络效益的博弈问题.文中提出了一种无线多媒体传感器网络QoS路由博弈模型,并证明了纳什均衡的存在性.同时,给出了一种基于混合纳什均衡的无线多媒体传感器网络QoS路由算法.     

无线传感器网络中基于势能场的能量均衡模型

在无线传感器网中,现有的节能路由以找到能量消耗最小的路径为目标,导致围绕汇聚节点的能量空洞．网络能量均衡可以有效的利用和管理整个网络的节点能量,通过有效的分配网络负载,实现网络寿命的延长,网络效率的提高．本论文中提出了基于势能场的模型,建立了基于势能的路由,并且通过相位切换技术,达到局部和全局的能量均衡,从而延长无线传感器网络的使用寿命．     

An improved ring signature scheme without trusted key generation center for wireless sensor network

Security of wireless sensor network (WSN) is a considerable challenge, because of limitation in energy, communication bandwidth and storage. ID-based cryptosystem without checking and storing certificate is a suitable way used in WSN. But key escrow is an inherent disadvantage for traditional ID-based cryptosystem, i.e., the dishonest key generation center (KGC) can forge the signature of any node and on the other hand the node can deny the signature actually signed by him/herself. To solving this problem, we propose an ID-based ring signature scheme without trusted KGC. We also present the accurate secure proof to prove that our scheme is secure against existential forgery on adaptively chosen message and ID attacks assuming the complexity of computational Diffie-Hellman (CDH) problem. Compared with other ring signature schemes, we think proposed scheme is more efficient.     

UWB传感器网络跨层优化模型的构建与实现

跨层设计是提高无线传感器网络整体性能的一种有效方法．文中在综合考虑MAC层调度、物理层功率控制、网络层路由三方面因素的基础上，结合UWB技术超带宽、低信号功率的特点，以实现网络最大数据传输速率为目标，构建了UWB传感器网络跨层优化模型．仿真实验结果表明，根据模型最优解进行网络配置可充分利用网络资源、显著提高网络的数据传输速率，以构建、求解优化模型的方式解决网络跨层问题是切实可行的．     

Ad Hoc网络保持连通度的临界传输范围的研究

连通度是Ad Hoc网络的根本属性.保持网络的连通性对于提高网络的吞吐量至关重要.目前的研究主要以概率论方法为理论基础,讨论节点的发射半径在什么范围内,保持Ad Hoc网络的k连通.文中对Ad Hoc网络连通度目前的研究进展进行了综述,在引入能量模型的基础上,对Ad Hoc网络的连通度进行了仿真,并基于仿真结果,提出了Ad Hoc网络保持连通的临界传输范围,最后对将来的研究方向进行了展望.     

An authenticated group key distribution scheme for wireless sensor networks

In wireless sensor networks (WSNs), group key distribution is the core of secure communications since sensor nodes usually form groups and cooperate with each other in sensing data collection and in-network processing. In this paper, we present a scalable authenticated scheme for group key distribution based on a combinatorial exclusion basis system (EBS) for efficiency and one-way hash chains for authentication. The proposed scheme guarantees a lightweight authenticated group key updating procedure and is efficient in terms of storage, communication and computation overheads. Foundation item: the National High Technology Research and Development Program (863) of China (Nos. 2006AA01Z436, 2007AA01Z455, and 2007AA01Z473).     

无线传感器网络中能量有效分簇路由算法

由于无线传感器节点的电源能量有限,提出了一种能量有效分簇路由算法(EECRA).该算法是基于最小能量的数据转发并运用于簇内路由中,簇头由基站根据节点的剩余能量和簇头之间的距离来选定,为了减小簇头节点的能量开销,簇头之间采用了多跳中继的方式将采集的数据发送到基站.仿真结果证明:该算法与LEACH协议相比,不仅提高了网络寿命,同时节点的能耗均衡性、网络扩展性和可靠性都大大的提高.     

Network lifetime global optimization for multi-source and single-sink topology in wireless sensor networks

The multi-source and single-sink (MSSS) topology in wireless sensor networks (WSNs) is defined as a network topology, where all of nodes can gather, receive and transmit data to the sink. In energy-constrained WSNs with such a topology, the joint optimal design in the physical, medium access control (MAC) and network layers is considered for network lifetime maximization (NLM). The problem of integrating multi-layer information to compute NLM, which involves routing flow, link schedule and transmission power, is formulated as a non-linear optimization problem. Specially under time division multiple access (TDMA) scheme, this problem can be transformed into a convex optimization problem. To solve it analytically we make use of the property that local optimization is global optimization in convex problem. This allows us to exploit the Karush-Kuhn-Tucker (KKT) optimality conditions to solve it and obtain analytical solution expression, i.e., the globally optimal network lifetime (NL). NL is derived as a function of number of nodes, their initial energy and data rate arrived at them.Based on the analysis of analytical approach, it takes the influence of data rates, link access and routing method over NLM into account. Moreover, the globally optimal transmission schemes are achieved by solution set during analytical approach and applied to algorithms in TDMA-based WSNs aiming at NLM on OMNeT<++> to compare with other suboptimal schemes.