ZigBee网络中Cluster-Tree拓扑的改进与优化

无线传感器网络(WSN)是一种具有感测、计算和传输能力的小型传感器节点的集合。由于单个传感器节点的功能有限,特别是能量的存储和数据的存储,所以需要制定良好的网络拓扑结构和路由协议。文中重点研究基于IEEE 802.15.4标准的Zig Bee无线传感器网络,提出基于最小生成树(MST)的高效聚类拓扑结构MSCT,最终的目的在于以最小的成本构建一个网络拓扑结构。文中的拓扑结构还考虑了室内环境,提出了处理墙壁和障碍物导致的路径损耗和信号衰减的度量,并计算节点之间的链接的权重。最后,通过能量的损耗和网络的寿命来论证文中提出的MSCT拓扑结构比Cluster-Tree拓扑结构更具有优势性。     

基于休眠和扇区的传感器网络拓扑控制算法

拓扑控制算法对节省无线传感器网络节点能量、延长网络寿命具有重要意义。无线传感器网络节省节点能量有两种方法：层次型拓扑结构控制和功率控制；但目前还没有算法将以上两种方法相结合。丈中是结合周期性休眠和拓扑控制的一种新型拓扑控制策略：基于休眠和扇区的无线传感器网络拓扑控制算法，将拓扑控制算法和节点的休眠结合起来。仿真结果表明：算法在不降低网络吞吐量条件下节省了网络能量消耗，有效延长网络寿命。     

传感器网络中基于最短路径树的低延时节能路由算法

借助图论中最短路径和最小生成树的原理,在无线传感器网络中构建若干棵以Sink节点为根的最短路径源路由树。与最小生成树相比,最短路径树能保证路径上大部分节点找到节点间RSSI较强的通讯路径并以较少的跳数把数据传输给Sink节点,而最小生成树中的节点则需较多跳数。因此,提出的算法在一定程度上降低了延时。算法通过事先设定最低RSSI和节点最大剩余能量MRE来构建路由树,并修改已存在的路由算法,从而保证节点通讯的可靠性和网络的节能。     

无线传感器网络拓扑控制分析

无线传感器网络的拓扑控制对网络的性能有很大影响。拓扑控制的目标是用最小的能量维持网络拓扑。目前,对拓扑控制算法的研究主要分为集中式和分布式两种。文章简要介绍了无线传感器网络中拓扑控制研究的意义,总结了无线传感器网络的拓扑结构及现有的一些拓扑控制算法,最后探讨了存在的问题和今后的发展方向。     

WSNs中基于能量代价的最小权和支配集拓扑控制算法

该文针对无线传感器网络中最小连通支配集拓扑并非网络耗能最小拓扑的问题,定义由节点剩余能量,邻居个数和通信代价构建的能量代价函数综合反映支配节点的能量效率以及对降低网络整体能耗的贡献,进而以其作为拓扑权值,提出一种基于能量代价的最小权和连通支配集拓扑控制算法。算法选取局部最小权值节点担负支配任务,搭建整体权和最小的支配集,最小化网络整体能耗。实验结果表明,算法不仅具有节能的特点,还确保了通信链路的可靠性,有效延长了网络生命周期。     

传感器网络中基于模拟退火算法的拓扑控制方案

为了研究符合网络生命期目标要求的传感器网络拓扑控制方案,针对传统方案所获拓扑的连通冗余度过高或结构健壮性较低等弊端,从理论上对拓扑需求进行了建模分析,最终转化模型为度约束最小生成树问题,并设计了一种模拟退火算法对该问题进行处理,进而提出了一种基于模拟退火算法的拓扑控制方案。通过实验对方案进行了性能分析和验证,结果表明该方案所获拓扑具有网络整体功耗低、结构健壮性高和节点间通信干扰可控的折衷特点,并能够有效地延长传感器网络生命期。     

基于多簇点简化的K容错能量均衡拓扑控制方案

针对异构监测传感器网络结构,设计了一个容错拓扑控制方案,在可以减少网络冗余的同时,兼顾了网络的稳定性,并且保证生成拓扑具有最小的能量消耗。该方案首先将异构监测传感器网络简化为同构传感器网络以简化计算,然后根据节点的位置信息,建立各监测节点到簇节点的能量消耗最小,并且可以保证K容错的K连通子图。该方案在保证传感器网络K连通的前提下,可以最大限度减少传感器网络中的冗余路径,且可以较好地均衡无线传感器网络能耗,延长网络生命周期。     

基于滑动区域的粒子群虚拟网节能映射算法

针对传统虚拟网节能映射中存在的节点映射分散、链路映射跳数多等问题,利用虚拟网请求的最小生成树拓扑将节点和链路同时映射,该文提出了基于滑动区域的粒子群虚拟网节能映射算法(EVNE_SRPS)。当一个虚拟网请求到达时,生成其最小生成树拓扑,根节点为路径和最短的节点;在底层网络随机选取多个区域作为粒子对象,并在区域中心映射虚拟网请求的最小生成树拓扑;计算粒子的适应度,求出群体和个体最优解,并在最优解的指导下确定滑动方向、更新区域位置,经过迭代后得到虚拟网的映射方案。实验结果表明,与现有算法相比,该算法降低了网络能耗,提高了运营商的收益成本比。     

无线Ad Hoc网络Steiner树实现协议研究

针对无线Ad hoc网络多跳,拓扑结构随时可能动态变化,协作节点间数据传输需实时性强等问题,利用Netlog语言宣告声明最小Steiner树协议的构造算法方法适应解决。协议可快速构造一棵近似最小的Steiner树,每个节点独立运行声明Steiner树协议,构造Steiner节点间的虚拟全联通网络,在此网络上构造最小代价生成树;然后将此树的节点与边对应原网络的节点和边,继续构造最小代价生成树,最后将此树上的非Steiner节点的叶子节点删除,近似得到最小代价Steiner树,该方法在实验平台上得以验证,为无线移动网络中资源的选择利用提供了一种新的可尝试性的新方法。     

基于内容的无线传感器网络路由协议

针对无线传感器网络环境下低功耗路由问题,根据无线传感器网络是一种以数据为中心的网络的特点,提出了一种基于内容的低功耗路由协议CBP。其基本思想是:Sink节点根据上层应用构造谓词,并对谓词进行广播,网络中所有传感节点以Sink节点的谓词为依据建立路由表,实现数据路由。与现有无线传感器网络路由协议相比较,此路由协议具有低功耗,占用节点资源少,网络容错能力强等特点。仿真结果表明,在节点数量大于100的大规模网络中,基于内容的无线传感器网络路由协议功耗比定向扩散协议功耗降低19%。     

A Sensor Network Cross-Layer Power Control Algorithm that Incorporates Multiple-Access Interference

This paper presents a wireless sensor network (WSN) transmit power control algorithm designed to minimize WSN node energy consumption. The algorithm determines transmit power levels using an optimization that accounts for energy consumed by the physical and link layers of the protocol stack. This cross-layer optimization incorporates a physical layer model that uses knowledge of the WSN medium access control (MAC) layer algorithm to accurately model multiple access interference (MAI). Analytical and simulation results show that accounting for MAI in this fashion results in a significant energy savings relative to comparable WSN power control algorithms.     

容错能量均衡WSN拓扑控制方案研究

针对WSN（Wireless Sensor Net）结构中存在大量的网络覆盖冗余与节点唤醒时间的延长,耗费了资源同样也增加了节点的工作能耗的特点。设计了一个拓扑控制方案,减少网络冗余的同时,兼顾了网络的鲁棒性。并且保证生成拓扑具有最小的能量消耗。该方案根据节点的位置信息。建立各监测节点到簇节点的能量消耗最小并且可以保证...     

Transmit Power Distribution of Wireless Ad-hoc Networks with Topology Control

Topology control and routing protocols are used by designers of wireless packet data networks to lower the node degree, simplify routing and lower the nodes' energy consumption, while preserving strong connectivity. We assume a popular fading channel model and study the impact of several topology control schemes on the transmit power of nodes randomly distributed over a large area according to a Poisson point process, where each node controls the pattern of its one-hop neighbors by independently adjusting its transmit power. We provide the distribution of the transmit power of individual nodes under several different topology control algorithms, allowing designers to estimate the life time of battery energized devices, and the implications of choosing the nodes' peak transmit power. We also allow easy comparisons between several different topology control algorithms with respect to the nodes' power consumption.     

Localized Interference-aware and Energy-conserving Topology Control Algorithms

Energy conservation and interference reduction are the two ultimate goals of topology control in wireless multihop networks. However, the existing energy-conserving algorithms rarely consider interference reduction or at most consider it implicitly. It has been proved that the power-efficient topology does not guarantee low interference. Considering that in any topology, the nodes affected by the communications between any other nodes should be as few as possible, we propose in this article two algorithms, the interference-aware local minimum spanning tree (MST) based algorithm (IALMST) and the interference-bounded energy-conserving algorithm (IBEC). In IALMST, each node builds its local MST independently according to the costs of interference and energy consumption, while in IBEC, each node commonly selects the edge with the least energy consumption, and only when the interference exceeds a predefined bound, it is allowed to select a more expensive edge to reduce interference. Theoretical analysis and simulations illustrate that both algorithms can effectively conserve energy and reduce interference.

无线传感器网络节点节能管理方式的研究

无线传感器网络节点数量众多、自身携带的能量十分有限。为了延长网络的生命周期,需采用有效的策略降低能耗。在研究无线传感器网络节点组成结构、能量消耗以及节点间传播方式的基础上,提出一种为有效地达到节能目的所采用的节点管理方式。该方案采用动态选择簇头节点的自组织、多跳路由、层次式拓扑组织结构的路由协议、快速的数据融合技术,并在实现硬件的低功耗设计的条件下进行动态功耗管理。     

局部构造邻居最优能耗路的拓扑控制算法

无线传感器网络拓扑控制算法的首要任务是减少节点的能量消耗,从而延长整个网络的生存时间。而传感器节点大部分的能量消耗在无线通信模块。在分析了拓扑控制算法所基于的两种模型(UDG,MG)以及两种不同性质的网络(homogenous net,heterogeneous net)的基础上,考虑到在通常情况下,无线通信的能量消耗与通信距离的3次方成正比。基于此,针对能否设计一种选择邻居的标准,使邻居间的链接都是最小能耗链接这一问题,给出了一种构造最小能耗路的邻近图算法MEP(MG)。证明了算法具有连通性和1-spanner特性。     

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.     

Design of RF transceivers for wireless sensor networks in hazardous applications

Wireless sensor networks (WSN) have a great prospect in many applications, among which the monitoring of hazardous environments is becoming more and more important. The basic requirements of WSN design are low cost and low power consumption, and then a low-power system-on-chip implementation is an optimal solution for WSN nodes. However, the radio-frequency (RF) part of a node chip is usually power hungry and difficult to fully integrate, so many previous works have focused on the design of RF transceivers for WSN. Specifically, for hazardous applications, the communication range is required to be long enough to protect human from harmful environments. So a long effective communication distance is also necessary for WSN transceivers in hazardous applications. In this paper, we give a survey and a classification of WSN transceivers. Furthermore, we analyze the advantages and disadvantages of three main WSN transceivers, i.e. on-off keying transceivers, ultra-wide band transceivers, and frequency shift keying transceivers; and then find out the one most suitable for hazardous applications.     

无线传感器网络的覆盖优化机制研究

如何实现最优覆盖是无线传感器组网的一个基本问题.文章分析了传感器覆盖问题的背景,给出了节点调度方案的主要方法和技术原理,探讨了基于网络能量高效的覆盖优化与网络连通性之间的关系,重点阐述了实现区域覆盖和点覆盖的机制.对于覆盖薄弱地区,文章提出了采用分簇方式将覆盖地区划分成许多子区域或簇,用动态移动修复机制提供细粒度的网络监测与覆盖控制.文章认为调度传感器节点在休眠和活动模式之间进行切换,是一种重要节能方法;对于资源受限且拓扑动态变化的无线传感器网络,宜采用分布式和局部化的覆盖控制协议和算法.     

Efficient flow‐control algorithm cooperating with energy allocation scheme for solar‐powered WSNs

Recently, solar energy emerged as a feasible supplement to battery power for wireless sensor networks (WSNs) which are expected to operate for long periods. Since solar energy can be harvested periodically and permanently, solar‐powered WSNs can use the energy more efficiently for various network‐wide performances than traditional battery‐based WSNs of which aim is mostly to minimize the energy consumption for extending the network lifetime. However, using solar power in WSNs requires a different energy management from battery‐based WSNs since solar power is a highly varying energy supply. Therefore, firstly we describe a time‐slot‐based energy allocation scheme to use the solar energy optimally, based on expectation model for harvested solar energy. Then, we propose a flow‐control algorithm to maximize the amount of data collected by the network, which cooperates with our energy allocation scheme. Our algorithms run on each node in a distributed manner using only local information of its neighbors, which is a suitable approach for scalable WSNs. We implement indoor and outdoor testbeds of solar‐powered WSN and demonstrate the efficiency of our approaches on them. Copyright © 2010 John Wiley & Sons, Ltd.