基于局域世界的无线传感器网络分簇演化模型

当前无线传感器网络无标度演化模型研究往往将网络视为同质网络,且未充分考虑网络在真实情形下的演化特征,导致所获网络拓扑与实际网络差异明显。因此,基于局域世界理论,考虑无线传感器网络典型分簇结构、能耗敏感与真实网络中普遍存在的节点与链路退出的动态性行为等特征,提出无线传感器网络分簇演化模型。该模型与同类研究成果相比,更为接近真实网络情形。利用平均场理论推导出此模型具有无标度特征。通过研究拓扑生长对网络容错性能影响,发现扩大局域世界规模与提升饱和度约束上限可有效提升网络容错性能。与之相反,簇头比例与节点删除概率的上升将导致网络容错性能的下降。     

基于稳定链路的WSNs拓扑优化算法设计及仿真研究

无线传感器网络在物联网中占有重要地位,其能够降低能耗并有效保障数据传输。然而,无线传感器网络底层拓扑结构通常存在网络链路质量低、网络能耗高、网络干扰等问题。针对现有网络链路不稳定的问题,提出具有稳定链路的幂律可调优化算法,并对其生成的拓扑动态性能进行研究。通过网络节点失效容错需求仿真和链路稳定性仿真,验证了幂律可调优化算法的准确性,为无线传感器网络拓扑优化提供参考。     

能量异构无线传感器网络容错拓扑研究

该文针对能量异构无线传感器网络中的节点失效问题,提出度分布可调的容错拓扑结构(ADD),并给出了拓扑的度分布表达式,进而通过解析度分布属性对拓扑容错性的影响,得出在能量耗尽与环境损毁综合节点失效情况下可较长时间维持监测任务的网络拓扑。仿真实验结果表明,新的容错拓扑结构获得了更长的生存时间,具有更好的容错性能。     

一种基于适应度和节点聚类的P2P拓扑建模方法

 通过对Gnutella网络拓扑实测数据的分析,得到了Gnutella网络的累积节点度分布、聚类系数、平均路径长度和rich-club系数等拓扑特征。在拓扑特征分析的基础上,通过引入适应度、邻居数限制和节点聚类等机制,提出了面向非结构化P2P网络拓扑的FCL(Fitness model with tunable Clustering and neighbours Limitation)模型,并给出了建模算法。通过实验分析,证明了该模型的有效性。     

基于最优刚性图的能量有效分布式拓扑控制算法

针对现有无线传感器网络拓扑控制算法无法平衡各节点能量消耗的问题,基于最优刚性图提出了一种具有平衡负载特性的能量有效分布式拓扑控制算法。算法引入综合反映能量消耗及剩余能量两方面因素的链路权值函数,能够根据当前节点剩余能量实时地动态优化拓扑结构,从而有效地平衡网络节点的能量消耗。从理论上证明了优化后的拓扑是2?连通的而且具有稀疏性;同时优化后拓扑中各节点的平均度趋于4。仿真结果表明,与其他算法相比,该算法能够有效地平衡各节点的能量消耗,进而延长网络生命期。     

基于仿人体血管路径WSN故障容错路由算法研究

为提高无线传感器网络(WSN)故障容错性和传输稳定性,实现网络负载均衡,提出了一种仿人体血管路径的WSN故障容错路由算法.通过研究人体血管路径特性,将其引入到WSN故障容错路由设计中,在对网络节点分区域进行等级标定的基础上实行能耗均衡的静态分簇;运用改进的蚁群算法生成节点路径并计算各路径信息素值,以确定传输路径选择概率并建立仿血管拓扑结构路由.理论与仿真结果表明,此算法具有良好的性能.     

互联网网络单节点失效容错特性研究

容错性是大型网络的重要特性,而现有的评测参数难以进行准确的评价。引入路径损失作为评测参数,通过对因特网自治系统（AS,Autonomy System）网络拓扑数据的分析,研究了单节点失效情况下网络的容错特性,并与经典的网络模型相比较。结果表明,AS网络的容错特性表现出网络规模无关性,单节点失效引起的路径损失呈幂率规律变化,度较大和度较小的节点都可能对网络容错性产生较大影响,而现有的网络模型未能成功模拟AS网络的容错特性。     

一种主动均衡节点能耗的无线传感器网络拓扑控制算法

无线传感器网络中网络拓扑的动态调整对于提高路由协议和MAC协议的效率,延长网络的生存期,提高网络通信效率等方面具有重要的作用.本文在分析了一些拓扑控制算法的基础上,提出了一种新的层次型拓扑生成算法,该算法引入了时间门限值和节点剩余能量两个参数,在解决能耗不均衡问题上采取相对主动的方法.能够有效地均衡网络节点的能耗并延长网络的生存周期.     

无线传感器网络拓扑的容错度与容侵度

研究传感器网络拓扑对节点失败的容忍能力,必须解决三个基本问题,容忍节点失败的定义是什么,如何评价拓扑的这种容忍能力,什么样的拓扑具有较高的容忍能力.当前有关无线网络容错拓扑的研究均将图的多连通性看成拓扑的容错性,以图形多连通度的大小来衡量拓扑容错性的高低.本文通过实例分析指出图的多连通性与容错性是不同的,并结合网络的可用性,给出拓扑对失败节点容忍的定义,在此基础上,根据随机故障和恶意入侵两类节点失败形成原因,给出了拓扑容错度和容侵度作为拓扑对节点失败容忍能力高低的评价标准,并利用这两个标准分析了传感器网络分层拓扑,得出其拓扑容错度随簇头节点比例提高递减、而容侵度随之递增的理论结果.     

基于局域世界的WSN拓扑加权演化模型

 无标度加权网络模型,反映了现实网络的存在形式和动力学特征,是无线传感网络建模和拓扑演化的有效研究工具.本文基于局域世界理论提出一种不均匀成簇的无线传感网络拓扑动态加权演化模型,考虑节点能量,通信流量和距离等因素,对边权重和节点强度进行了定义,同时研究了拓扑生长对边权重分布的影响.实验证明演化所得网络节点度,强度和边权重均服从幂律分布,结合已有理论成果可知,该拓扑不仅继承了无权网络较高的鲁棒性和抗毁性,同时降低了节点发生相继故障的几率,增强了无线传感网络的同步能力.     

Energy‐Connectivity Tradeoff through Topology Control in Wireless Ad Hoc Networks

In this study, we investigate topology control as a means of obtaining the best possible compromise between the conflicting requirements of reducing energy consumption and improving network connectivity. A topology design algorithm capable of producing network topologies that minimize energy consumption under a minimum‐connectivity constraint is presented. To this end, we define a new topology metric, called connectivity efficiency, which is a function of both algebraic connectivity and the transmit power level. Based on this metric, links that require a high transmit power but only contribute to a small fraction of the network connectivity are chosen to be removed. A connectivity‐efficiency‐based topology control (CETC) algorithm then assigns a transmit power level to each node. The network topology derived by the proposed CETC heuristic algorithm is shown to attain a better tradeoff between energy consumption and network connectivity than existing algorithms. Simulation results demonstrate the efficiency of the CECT algorithm.     

基于邻居节点的拓扑控制算法研究与仿真

拓扑控制是移动自组织网络提高网络能量利用率和网络容量的一种重要机制。针对移动自组织网络拓扑易变、带宽和能量有限等特点,简要介绍了一种节约节点能耗,有效提高整个网络寿命的拓扑控制算法;通过对基于邻居个数的拓扑控制协议K-Neigh算法的仿真,研究了不同k值的选择下拓扑控制对节点功耗和网络性能(包括吞吐量、丢包率和时延等)的影响。其结果表明选择合适的k值可以取得节点功耗和网络性能的平衡,而且经过K-Neigh拓扑控制后的网络具有很好的鲁棒性。     

面向节点异构的能耗感知虚拟网络映射算法

在底层网络节点异构的环境中,能耗优化的虚拟网络映射问题并不是最小化工作节点和链路数。该文针对此问题,构建底层网络节点和链路的负载能耗模型,并以能耗最优为目标,建立虚拟网络映射问题的数学模型,提出一种能耗感知虚拟网络映射算法。该算法在节点映射阶段以最小化能耗和协调链路映射为原则,将虚拟节点映射至综合资源能力最大的底层节点上,并采用改进的能耗感知k最短路径法进行链路映射。仿真结果表明,该算法显著减少虚拟网络映射的能耗,且底层网络节点异构性越大,能耗优势更为明显。     

基于时频联合碎片感知的资源均衡虚拟光网络映射算法

为了解决虚拟光网络映射中带宽阻塞率较高以及底层资源消耗不均匀问题,论文提出一种基于时间域-频谱域碎片感知的虚拟网络映射(FA-VNM)算法。该文综合考虑频隙在时间域和频谱域上的碎片问题,设计时频联合碎片公式最小化分配过程中的频谱碎片。进一步,为了均衡网络中的资源消耗,在FA-VNM算法基础上提出基于节点度数的负载均衡感知虚拟网络映射(LB-VNM)算法,设计物理节点平均资源承载能力的公式,优先映射物理节点平均资源承载能力大的节点;为了均衡路径上资源使用,考虑路径权重值,并根据每条路径的权重值对虚拟链路进行映射,从而降低阻塞率。仿真结果表明,所提算法能有效降低阻塞率,提高资源利用率。     

Distributed Cooperative Control Algorithm for Topology Control and Channel Allocation in Multi-radio Multi-channel Wireless Sensor Network: From a Game Perspective

With the development of wireless communication technology, the spectrum resource is becoming more and more scarce, which results in the increase of network co-interference and then incurs the increase of data retransmission probability. Hence, the single channel based algorithms are facing a myriad of challenges. Moreover, reducing the energy consumption and prolonging the network lifetime is the key issue for wireless sensor network. In order to alleviate the interference while reducing and balancing the energy consumption, we tend to design a multi-radio multi-channel algorithm that joint the topology control and channel allocation. Firstly, we study the interactions between topology control and channel allocation, which lay the basis for the further reduction of transmission power and interference. We take account of the radio power, node residual energy and node interference to construct a cooperative control game model of topology and channel allocation. This game model has proven to guarantee the existence of Nash equilibrium. And then based on this game model, a distributed Cooperative Control Algorithm of Topology and Channel allocation (CCATC) is developed, which can converge to Nash Equilibrium and preserve the network connectivity. Furthermore, the simulation results demonstrate that CCATC can not only greatly reduce the interference but also prolong the network lifetime by balancing the energy consumption of nodes. The reduction of interference comes with the improvement of network throughput. Besides, CCATC has many other attractive features such as the higher channel utilization, the better robustness, the fairer channel allocation and the less end-to-end delay.     

The k-Neighbors Approach to Interference Bounded and Symmetric Topology Control in Ad Hoc Networks

Topology control, wherein nodes adjust their transmission ranges to conserve energy and reduce interference, is an important feature in wireless ad hoc networks. Contrary to most of the literature on topology control which focuses on reducing energy consumption, in this paper we tackle the topology control problem with the goal of limiting interference as much as possible, while keeping the communication graph connected with high probability. Our approach is based on the principle of maintaining the number of physical neighbors of every node equal to or slightly below a specific value k. As we will discuss in this paper, having a nontrivially bounded physical node degree allows a network topology with bounded interference to be generated. The proposed approach enforces symmetry on the resulting communication graph, thereby easing the operation of higher layer protocols. To evaluate the performance of our approach, we estimate the value of k that guarantees connectivity of the communication graph with high probability both theoretically and through simulation. We then define k-Neigh, a fully distributed, asynchronous, and localized protocol that uses distance estimation. k-Neigh guarantees logarithmically bounded physical degree at every node, is the most efficient known protocol (requiring 2n messages in total, where n is the number of nodes in the network), and relies on simpler assumptions than existing protocols. Furthermore, we verify through simulation that the network topologies produced by k-Neigh show good performance in terms of node energy consumption and expected interference.     

Joint processing of topology control and channel assignment in wireless ad hoc networks

Network topology construction and its channel assignment for each node in the constructed network topology are two main problems in the initialization of topology building. Topology control is an effective way to solve the problem of topology building. To investigate the joint effect of topology control and channel assignment, we propose a joint processing scheme composed of a k‐Neighbor topology control algorithm and a greedy channel assignment (GCA) algorithm in this paper. Based on this joint processing scheme, the relationships between the energy consumption, the total required channel number and the network connectivity are discussed. We also discuss the impact of some parameters on the performance of networks in terms of the path loss factor, node density, maximum node degree, etc. Our main contributions in this paper is that we find that topology control has a good effect on improving the performance of channel assignment, and the proposed joint processing scheme can reduce the required channel number effectively, compared with its theoretical upper bound. In particular, if the node degree in a network is not more than k, various simulations indicate that the required channel number is not more than 2k + 1. Copyright © 2008 John Wiley & Sons, Ltd.     

基于无线传感器网络的K均值算法研究

传统无线传感网一般由大量密集的传感器节点构成,存在节点计算能力、能源和带宽都非常有限的缺点,为了有效节能、延长网络寿命,介绍了基于聚类的K均值算法.该算法通过生成的簇头节点散播到网络的各个区域中,减少了每个区域内通信的能耗和可能会出现的一般节点过早死亡的情况,从而避免了网络对该区城提早失去监控.实验证明,该算法对各节点...     

分簇型无线传感器网络时间同步机制的研究

提出了一种基于分簇型网络结构的时间同步算法。算法的主要思想是通过在簇建立阶段利用LEACH优化算法优化网络拓扑结构,降低网络的跳数,从而降低了时间同步精度由于跳数增加而导致的误差积累,为时间同步算法提供一个良好的网络结构。在LEACH优化算法中,簇首选取机制融入簇首节点的剩余能量和密度因子,并且提出了助理簇首节点用以均衡簇首节点的能量消耗。同时在时间同步阶段,采用双向时间同步机制和单向广播时间机制。实验仿真证明,提出的时间同步算法降低了网路的跳数,提高了时间同步精度,降低了节点的能量消耗,提高了网路的运行时间,具有一定的实用价值。