带有能量补给的异构无线传感器网络拓扑控制算法

针对当前算法主要对拓扑构建或拓扑维护单独研究的问题,提出了一种将两个过程组合的拓扑控制算法,可以适应于通信和能量异构的网络。拓扑构建以较少的通信开销构建连通支配集,而拓扑维护由sink节点基于时间、能量或故障机制执行局部或全局修复策略以节约能量。理论分析和仿真实验证实,算法能以较少的时间和通信开销构建拓扑并延长网络生命时间。     

基于k连通的拓扑算法GKETA

主要研究了无线传感器网络的k连通拓扑控制问题。提出了一种新的基于k连通控制的拓扑算法GKETA,首先通过二元二次非线形回归法找到网络节点个数N,节点发射半径R,和连通度k之间的关系,通过最大发射功率构建初始k连通图。通过对算法的分析及大量比较实验,验证了GKETA算法在拓扑控制的冗余度和连通度上由于其k连通算法,节约了节点能量,具有更强的网络容错能力。     

基于节点控制的空间信息网拓扑重构算法

空间信息网是一种融合陆海空天信息系统的新型自组织网络,成为研究热点.针对网络特点和应用需求,提出一种预防和恢复相结合的拓扑重构策略,通过检测拓扑关键点触发预防性重构,通过拓扑故障触发恢复性重构,重构时在一定范围内选择冗余节点,该节点在虚拟力的导向下自主地移动剑待维护区域,并以修复区域的局部拓扑通信代价最小为目标,进行拓...     

一种基于拓扑势的虚拟网络映射算法

该文针对现有的虚拟网络映射算法对网络中节点的拓扑属性考虑不够周到,导致其请求接受率和收益开销比较低的问题,将物理学里的场论思想引入了虚拟网络映射,并提出一种基于拓扑势的虚拟网络映射算法。该算法在节点映射阶段,通过计算节点的拓扑势、节点的资源能力、待映射节点与已映射节点之间的距离,将虚拟节点映射至最佳的物理节点。在链路映射阶段,通过计算物理路径的可用带宽和路径跳数,将虚拟链路映射至最佳的物理路径。仿真实验表明,该算法在多种虚拟网络到达强度下的请求接受率和收益开销比均优于当前的虚拟网络映射算法。     

新的无线传感器网络分簇算法

针对无线传感器网络节点能量受限的特点,提出了一种响应式分布分簇算法(RDCA,responsive distributedclustering algorithm).该算法不需预先得知节点自身及其他节点的位置信息,而仅根据局部拓扑信息快速进行分布式的簇头选举,并根据代价函数进行簇的划分,适用于周期性获取信息的无线传感器网络.分析与仿真表明,该算法具有良好的负载平衡性能和较小的协议开销,与LEACH协议相比,能够减少能量消耗,网络生存期大约延长了40%.     

基于分层自治域空间信息网络模型与拓扑控制算法

针对空间信息网络结构复杂、拓扑动态变化以及空间尺度大等特点,提出一种面向空间信息网的分层自治域模型。该模型根据节点属性、链路能力、任务特点、分布区域等不同,将整个网络划分为不同的自治域和子自治域,各域内可采用相对独立的控制策略,从而将子网间各动态因素解耦合。然后,基于该分层自治域模型,提出了一种最小化时延的拓扑控制算法。与现有的集中式和分布式拓扑控制方法不同,该算法采用混合式方法,将控制信息约束在相邻子自治域范围内,既保证了网络的连通性,又减少了控制信息的开销。理论分析表明,若网络的物理拓扑是k连通的,则该算法得到的拓扑控制结果一定是k连通的。仿真结果验证了理论分析和所提出算法的有效性。     

移动P2P网络安全拓扑构造协议

针对移动对等(MP2P)网络的安全问题,提出一种MP2P网络安全拓扑构造协议(AMPSTP).AMPSTP协议首先利用Fortune算法完成对地理区域的划分,然后给出临时锚节点的选取和更新策略、MP2P覆盖网拓扑模型的构造和维护机制、MP2P覆盖网的路由发现算法以及基于博弈的MP2P覆盖网的节点选择机制.最后对AMPSTP协议的性能进行理论分析和仿真实验.结果表明,与MADPastry协议相比AMPSTP协议不仅可以保障网络安全和提高网络性能,而且还大大降低了控制开销.     

弹性拓扑控制技术研究

为了提高无线自组织网络的鲁棒性,针对现有的拓扑控制技术不能解决网络中一个信道被干扰且多个节点同时失效而造成的网络分割问题,提出了一种弹性可重构的二信道连通且k点连通的分布式拓扑控制方法,该方法可根据网络环境的变化动态改变网络的拓扑结构,实现在网络任意一个信道被干扰的情况下仍能维持k点连通。仿真结果表明,相比于现有的拓扑控制算法,所提方法不仅能够增强网络的鲁棒性,还能降低节点能耗,延长网络生存期。     

基于数据骡子的无线传感器网络拓扑控制综述

在节点部署稀疏、环境恶劣和网络不连通等情况下,WSNs(Wireless Sensor Networks)易出现网络孤岛、能量空洞、节能与恶劣环境网络节点部署等问题。针对这些问题,首先结合拓扑控制算法,对基于静态、动态小世界WSNs拓扑控制研究现状分别进行阐述,并在此基础上着重论述了基于动态小世界WSNs拓扑控制——Data MULEs(Data Mobile Ubiquitous LAN Extensions)的拓扑模型构造、最优轨迹、数据转发流程三个研究方向的算法设计与研究现状,基于此,最后指明了未来应开展的研究工作。     

无线传感器网络自适应功率控制策略

无线传感器网络功率控制技术对于网络的拓扑连通、能量效率、网络容量、吞吐量、实时性等性能均有显著影响,是其实用化的重要支撑技术。该文提出了一种适用于无线传感器网络的自适应功率控制策略APCS(Adaptive Power Control Strategy),该策略是只需要局部信息的分布式算法,通过调整路径损耗指数和功率控制参数可以获得性能极佳的目标拓扑,并能满足实时性和容错能力要求较高的应用场景。另外,该算法还采用了动态功率调整以保持网络的连通性,延长网络的生命周期。仿真结果证实了所提方法的有效性。     

Topology Management in Directional Antenna-Equipped Ad Hoc Networks

With fully directional communications, nodes must track the positions of their neighbors so that communication with these neighbors is feasible when needed. Tracking process introduces an overhead, which increases with the number of discovered neighbors. The overhead can be reduced if nodes maintain only a subset of their neighbors; however, this may increase the length of paths between node pairs in the network. In this work, we study the tradeoffs between node degree and path stretch. We first design a topology control algorithm to optimize this tradeoff. Assuming that nodes communicate with their directional neighbors using circular directional transmissions, we model the original graph as a unit disk graph (UDG). Given a UDG G, our algorithm finds a sparse subgraph G' with a maximum degree of 6, and connecting each node pair u,v by a path of length hops_{G'}(u,v)=O(hops_G(u,v)+logDelta), where Delta is the maximum degree in G, hops_{G}(u,v) denotes length of the shortest path between u, v in G. We show that this result is near-optimal. Based on the insights gained from this design, we next construct a simpler, more practical scheme that integrates fully-directional neighbor discovery and maintenance with topology control strategy. We simulate both algorithms and compare their performances.     

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.     

Angular MST‐Based Topology Control for Multi‐hop Wireless Ad Hoc Networks

This letter presents an angular minimum spanning tree (AMST) algorithm for topology control in multi‐hop wireless ad hoc networks. The AMST algorithm builds up an MST for every angular sector of a given degree around each node to determine optimal transmission power for connecting to its neighbors. We demonstrate that AMST preserves both local and network‐wide connectivity. It also improves robustness to link failure and mitigates transmission power waste.     

HEED: a hybrid, energy-efficient, distributed clustering approach for ad hoc sensor networks

Topology control in a sensor network balances load on sensor nodes and increases network scalability and lifetime. Clustering sensor nodes is an effective topology control approach. We propose a novel distributed clustering approach for long-lived ad hoc sensor networks. Our proposed approach does not make any assumptions about the presence of infrastructure or about node capabilities, other than the availability of multiple power levels in sensor nodes. We present a protocol, HEED (Hybrid Energy-Efficient Distributed clustering), that periodically selects cluster heads according to a hybrid of the node residual energy and a secondary parameter, such as node proximity to its neighbors or node degree. HEED terminates in O(1) iterations, incurs low message overhead, and achieves fairly uniform cluster head distribution across the network. We prove that, with appropriate bounds on node density and intracluster and intercluster transmission ranges, HEED can asymptotically almost surely guarantee connectivity of clustered networks. Simulation results demonstrate that our proposed approach is effective in prolonging the network lifetime and supporting scalable data aggregation.     

Topology control for multihop packet radio networks

A distributed topology-control algorithm has been developed for each node in a packet radio network (PRN) to control its transmitting power and logical neighbors for a reliable high-throughput topology. The algorithm first constructs a planar triangulation from locations of all nodes as a starting topology. Then, the minimum angles of all triangles in the planar triangulation are maximized by means of edge switching to improve connectivity and throughput. The resulting triangulation at this stage, the Delaunay triangulation, can be determined locally at each node. The topology is modified by negotiating among neighbors to satisfy a design requirement on the nodal degree parameter. Simulations show that the final topology is degree-bounded, has a rather regular and uniform structure, and has throughput and reliability that are greater than that of a number of alternative topologies     

An energy‐efficient localized topology control algorithm for wireless ad hoc and sensor networks

Topology control plays an important role in the design of wireless ad hoc and sensor networks and has demonstrated its high capability in constructing networks with desirable characteristics such as sparser connectivity, lower transmission power, and smaller node degree. However, the enforcement of a topology control algorithm in a network may degrade the energy‐draining balancing capability of the network and thus reduce the network operational lifetime. For this reason, it is important to take into account energy efficiency in the design of a topology control algorithm in order to achieve prolonged network lifetime. In this paper, we propose a localized energy‐efficient topology control algorithm for wireless ad hoc and sensor networks with power control capability in network nodes. To achieve prolonged network lifetime, we introduce a concept called energy criticality avoidance and propose an energy criticality avoidance strategy in topology control and energy‐efficient routing. Through theoretical analysis and simulation results, we prove that the proposed topology control algorithm can maintain the global network connectivity with low complexity and can significantly prolong the lifetime of a multi‐hop wireless network as compared with existing topology control algorithms with little additional protocol overhead. Copyright © 2008 John Wiley & Sons, Ltd.     

Effect of Selfish Node Behavior on Efficient Topology Design

The problem of topology control is to assign per-node transmission power such that the resulting topology is energy-efficient and satisfies certain global properties such as connectivity. The conventional approach to achieve these objectives is based on the fundamental assumption that nodes are socially responsible. We examine the following question: if nodes behave in a selfish manner, how does it impact the overall connectivity and energy consumption in the resulting topologies? We pose the above problem as a non-cooperative game and use game-theoretic analysis to address it. We study Nash equilibrium properties of the topology control game and evaluate the efficiency of the induced topology when nodes employ a greedy best response algorithm. We show that even when the nodes have complete information about the network, the steady state topologies are suboptimal. We propose a modified algorithm based on a better response dynamic and show that this algorithm is guaranteed to converge to energy-efficient and connected topologies. Moreover, the node transmit power levels are more evenly distributed and the network performance is comparable to that obtained from centralized algorithms.     

Distributed Topology Construction in ZigBee Wireless Networks

Topology control is one of the important techniques in wireless multi-hop networks to preserve connectivity and extend the network lifetime. This is more significant in ZigBee, since the address assignment scheme is tightly coupled with topology construction. For example, there can be orphan nodes that cannot receive the network address and isolated from the network due to predefined network configurations. In this paper, we propose a distributed topology construction algorithm that controls the association time of each node in order to solve the orphan node problem in ZigBee as well as construct an efficient routing tree topology. The main idea of the distributed topology construction algorithm is to construct primary backbone nodes by propagating the invitation packets and controlling the association time based on the link quality. Since the dynamically selected primary nodes are spread throughout the network, they can provide backbone to accept the association requests from the remaining secondary nodes which are majority in a network. In the performance evaluation, we show that the proposed topology construction algorithm effectively solves the orphan node problem regardless of network density as well as provides efficient tree routing cost comparable to the approximation algorithm for degree constrained minimum routing cost tree (DC-MRCT) problem.