异构传感器网络的一种可调节的拓扑控制算法

在无线传感器网络(WSN)的拓扑控制问题中,良好的拓扑结构能够提高路由协议和MAC协议的效率,但是WSN易受外界环境的影响,所以需要设计拓扑结构也能随着环境的变化而变化.而以前的拓扑结构大部分都是固定的,它们的缺点是不能适合环境的变化,并且已有的可调的拓扑结构都是针对同构WSN.针对该问题,提出了一种适用于异构WSN的可调的拓扑控制结构ATCH,该算法使得节点可以独立地调节拓扑结构,并且允许节点有不同的信道损失指数.通过证明和仿真实验显示,算法构造的拓扑图在保证网络连通的同时,能够很好的在能耗最低路径和低节点度之间进行调节.     

基于最短路径的异类传感器网络分布式拓扑控制

针对异类传感器网络提出了一种基于最短路径的分布式拓扑控制（SPD/TC）算法。该算法利用网络中所有节点的局部信息保持网络的连通性,同时,利用最短路径算法计算链接权值的大小来进行拓扑结构的调整。将该算法与DRNG算法的节点度和平均链接长度进行仿真分析,仿真结果表明：该算法能更有效降低干扰,节省网络能量,提高了网络的性能。     

IEEE 802.15.4 MAC协议能耗与时延均衡的GTS调度新算法设计

简述了IEEE 802.15.4 MAC协议中超帧结构和保护时隙(GTS)分配机制,分析了星状网络中信标使能模式下设备节点利用GTS方式通信时超帧结构中各参数对能耗与时延性能的影响.在此基础上设计了一种GTS调度新算法,该调度算法对时延期限小的节点优先进行GTS分配并在满足其时延要求情况下,根据业务量调节超帧结构中的超帧序号SO与信标序号BO,使设备节点能耗降到最低,从而实现星状网络中各节点的能耗与时延均衡,并用NS2仿真评估了调度新算法性能,其研究可为无线传感网络的实时应用系统提供参考价值.     

无线传感执行器网络中多源容错拓扑控制算法研究

拓扑控制是延长无线传感器网络生命时间的关键技术.针对异构网络的复杂性,提出了基于功率控制的分布式多源容错拓扑控制算法MSFT.在由大量计算、能量受限的传感器节点和少量性能较优的执行器节点组成的异构无线传感执行器网络模型中,算法保证任意传感器节点与执行器节点之间至少存在k条不相交路径同时选择权值较优节点使路径总功耗尽可能少,这样当任意k-1个节点失效时并不影响网络的连通性.理论分析证明算法能以O(n)的时间和消息代价构造网络拓扑,仿真实验进一步证实算法的有效性.     

无线传感网络中能量均衡的连通支配集算法

连通支配集是无线传感器网络中构建虚拟骨干网络的重要手段.由于支配集中节点的能耗相对其他节点要多,支配集中剩余能量较小的节点决定了虚拟骨干网的生命周期.现有算法或者只是关注构造较小的支配集,或者没有考虑调整能耗极快的支配节点.提出了一种能量均衡的连通支配集算法,基于节点剩余能量和连通度构造支配集,在网络运行过程中根据耗能速度,提前选择候选支配节点,分流负载过重的支配节点.仿真结果表明,新算法能以较小消息开销,有效延长网络寿命.     

无线传感器网络能量均衡拓扑模型研究

针对BA模型仅考虑节点寿命对网络拓扑结构影响的现状,考虑到拓扑能量利用率不高会缩短网络生命周期,在分析网络平均剩余能量和通信半径对网络生命周期影响的基础上,提出一种无线传感器网络能量均衡拓扑模型.该模型在拓扑演化过程中,综合考虑节点剩余能量、通信半径和节点度,并引入剩余能量调节参数、通信半径调节参数和节点度调节参数,最终使剩余能量大的节点连接概率更高.理论分析和仿真实验结果表明,该模型不仅具有无标度网络的幂律特性,具有较好的稳定性,且能够均衡节点和网络能耗,延长网络的生命周期.     

基于超立方体容错路由算法分析*

基于超立方体的优良的拓扑性质,提出了一个应用于超立方体网络的容错路由算法.该容错路由算法是基于局部信息的,因为路由算法在路由过程中,只需要知道其邻节点的信息,而无须知道其他节点的出错情况.对于给定的源节点和目的节点,路由算法均能够找到一条最优容错路径,并且可以预防死锁.模拟实验结果表明,路由算法所构造的路由路径长度接近于两个节点之间的最优路径长度.     

基于引力模型及相对路径数的节点重要度评估算法

准确度量复杂网络中节点的重要度对于研究网络结构和功能等方面具有重要的指导意义。现有多数节点重要度评估算法考虑了节点及其邻居节点的相关信息,却忽略了节点间的拓扑结构对节点重要度的影响。针对此问题,提出了基于引力模型及相对路径数的节点重要度评估算法。该算法首先分析了相对最短路径数对节点间信息传播的影响效果,同时考虑到非最短路径及路径距离等因素的影响,然后以三阶范围内邻居节点与中心节点的相互作用力之和定义节点重要度值,最后在六个真实网络中进行仿真实验。实验结果表明,所提算法不仅能有效区分网络中不同节点之间的重要度差异,还能准确度量网络节点的重要度大小。     

基于离散粒子群优化的工业无线网多信道分配算法

在充分考虑工业无线节点低能耗要求的基础上,提出一种工业无线网发射功率调节算法.在保证网络连通度的前提下,使无线节点发射功率尽可能小.同时,利用离散粒子群优化算法,提出一种解决工业无线网多信道分配问题的离散粒子群优化多信道分配算法（DPSO-CAA）.对标准离散粒子群优化算法加以改进.提高了所提出算法的全局搜索能力.通过将DPSO-CAA算法与已有算法进行的仿真对比实验,表明了所提出的DPSO-CAA算法能有效地降低数据碰撞和同信道干扰,而且能降低无线节点能耗.     

WSN中基于可信核心树的路由算法研究

介绍了一种适用于WSN网络的基于可信核心树的路由算法。该算法在局部范围内选取具有相对较高剩余能量和可信度的节点作为簇首节点,从而对整个网络进行分簇。然后通过一个最小能耗生成树算法将所有簇首节点组织成以Sink节点为根的可信核心树,进而对该树进行扩展,构建成覆盖全网的可信路由树。所有的数据沿着可信路由树上唯一的路径向Sink节点汇报。同时算法引入了可信模型,该模型通过检测网络中有数据包墓改、丢包、谎报等行为的恶意节点来评佑节点的可信度。实验结果证明,该TCTR算法能有效减小能耗、平衡负载,从而延长网络生存时间,同时能有效识别与隔离恶意节点,从而提高路径安全度与网络安全度。     

基于路径损耗的WSN拓扑控制算法

现有无线传感器网络拓扑控制算法大多基于理想网络模型,且需要节点位置信息。为此,提出一种基于路径损耗的拓扑控制算法。该算法无需任何节点位置信息,通过计算两节点间小于或等于3跳的前向与后向路径损耗,构建网络拓扑。仿真结果表明,该算法能降低网络能耗及节点间的通信干扰,保证网络连通性,延长网络生命周期。     

The r-Neighborhood Graph: An Adjustable Structure for Topology Control in Wireless Ad Hoc Networks

In wireless ad hoc networks, constructing and maintaining a topology with lower node degrees is usually intended to mitigate excessive traffic load on wireless nodes. However, keeping lower node degrees often prevents nodes from choosing better routes that consume less energy. Therefore, the trade-off is between the node degree and the energy efficiency. In this paper, an adjustable structure, named the r-neighborhood graph, is proposed to control the topology. This structure has the flexibility to be adjusted between the two objectives through a parameter r, 0lesrles1. More explicitly, for any set of n nodes, the maximum node degree and power stretch factor can be bounded from above by some decreasing and increasing functions of r, respectively. Specifically, the bounds can be constants in some ranges of r. Even more, the r-neighborhood graph is a general structure of both RNG and GG, two well-known structures in topology control. Compared with YG_k, another famous adjustable structure, our method always results in a connected planar with symmetric edges. To construct this structure, we investigate a localized algorithm, named PLA, which consumes less transmitting power during construction and executes efficiently in O(n logn) time     

An Adaptive Partitioning Scheme for Sleep Scheduling and Topology Control in Wireless Sensor Networks

This paper presents an adaptive partitioning scheme of sensor networks for node scheduling and topology control with the aim of reducing energy consumption. Our scheme partitions sensors into groups such that a connected backbone network can be maintained by keeping only one arbitrary node from each group in active status while putting others to sleep. Unlike previous approaches that partition nodes geographically, our scheme is based on the measured connectivity between pairwise nodes and does not depend on nodes' locations. In this paper, we formulate node scheduling with topology control as a constrained optimal graph partition problem, which is NP-hard, and propose a Connectivity-based Partition Approach (CPA), which is a distributed heuristic algorithm, to approximate a good solution. We also propose a probability-based CPA algorithm to further save energy. CPA can ensure K-vertex connectivity of the backbone network, which achieves the trade-off between saving energy and preserving network quality. Moreover, simulation results show that CPA outperforms other approaches in complex environments where the ideal radio propagation model does not hold.     

Topology control based on optimally rigid graph in wireless sensor networks

This paper presents an optimization scheme of sensor networks for node scheduling and topology control, aiming to reduce energy consumption for heterogeneous Wireless Sensor Networks (WSNs) with non-uniform transmission ranges. Motivated by geographical adaptive fidelity (GAF), we partition sensors into groups based on the location of sensors, such that a connected backbone network can be maintained by keeping only one arbitrary node from each group in active status while putting others to sleep. In addition, optimally rigid geographical adaptive fidelity (ORGAF) approach is proposed to decrease the communication complexity and reduce the energy dissipation. Furthermore, we prove the topology derived under ORGAF is 2-connected; and the average degree of nodes in the topology converges to four approximately. Simulation results show that ORGAF can improve the network performance as well as reducing the energy consumption.     

FDR: fault detection and recovery scheme for wireless sensor networks using virtual grid

Due to autonomous operation and constrained resources, nodes of a wireless sensor network are susceptible to failures. Due to multiple node failures, network topology may change or partition into many disconnected segments causing data/query path breakage. Early detection and recovery of faults is desirable in most scenarios. Also, due to limited battery life of a node, the solution must consume minimum possible energy for prolonged network operation. Hence in this paper, we propose a Fault Detection and Recovery scheme which is an energy efficient fault detection and recovery strategy that achieves minimum data loss by efficiently replacing faulty node on the present route or by finding full or partial alternate paths. Topology is managed by constructing a virtual grid over the entire network which helps in managing dynamically changing network topology easily and makes failure detection and recovery effective. It also helps to create energy efficient path between a source and a sink by finding shortest possible path. Further, nodes’ cooperation is exploited to create certain zones on the data/query path which provides alternate nodes or possible alternate paths if required on some node failures. Thus, scheme achieves fault tolerance and at the same time achieves energy efficiency by always selecting shortest path for data delivery between source and sink. Analytical and simulation study reveals the significant improvement in terms of fault detection and energy conservation over existing similar schemes.     

一种适合低连接度拓扑的集中式保护路由机制

在集中式路由中,由路由控制平台统一计算路由表进行分发,路由器不再具备决策能力,需要预先构建一种具备保护功能的路由机制,使得路由器的下游路径失效后都有立即可用的备份路径,确保报文的最小损失,已有的集中式保护路由机制在低连接度拓扑上保护效果不佳.为了解决该问题,提出了一种适合低连接度拓扑的集中式域内保护路由机制,允许失效处的相邻节点在没有可用路径时将报文返回至其上游节点,由有可用备份路径的上游节点通过备份路径发送,确保单个节点或连接失效后报文的最小损失.证明了为给定拓扑构建最优保护路由的问题是一个NP-hard问题,并且提出了解决该问题的三阶段启发式算法.在各种类型的拓扑中验证了启发式算法的性能.实验结果表明,该方法优于已有保护路由方案.     

Calibrating embedded protocols on asynchronous systems

Embedding is a method of projecting one topology into another. In one-to-one node embedding, paths in the target topology correspond to links in the original topology. A protocol running on the original topology can be modified to be executed on a target topology by means of embedding. However, if the protocol is tolerant to a number of faults - faults that affect the data but not the code of a distributed protocol executed by the nodes in a distributed systems - then the adapted protocol will not have the fault tolerance property preserved, due to the fact that links in the original topology can be embedded into paths of length greater than one: faults at the intermediate nodes on such paths are not accounted for in the protocol. We propose a communication protocol in the target topology that preserves the fault tolerance characteristics of any protocol designed for the original topology, namely by our mechanism the modification preserves fault tolerance.     

双环网络[+1]边优先最短路径及其寻径策略

双环网络是一种非常重要的互联网络结构 .传统的最优寻径方法没有充分利用这一网络中同一节点到不同节点的最短路径之间的关系 ,所给的算法不是最优的 .定义了双环网络的一种最短路径—— [+ 1]边优先最短路径 ,在此形式下 ,不仅最短路径的形式唯一而且同一源节点到不同目的节点的最短路径之间存在递推关系 .给出了相应的递推公式 ,运用此公式 ,平均不到两次加法运算和一次比较即可找到源节点到所有其它节点的最短路径 .利用所得结果 ,源节点只需存储很少的信息就可以通过简单计算求得到任意其它节点的最短路径 .与传统方法相比 ,本算法提高了系统的寻径效率     

AdHoc网络基于能量均衡的拓扑控制算法研究

为了延长无线AdHoe网络的生存期,降低节点传输过程中的功率消耗,该文提出了一种基于能量均衡的分布式拓扑控制算法,通过引人综合反映能量消耗及剩余能量两方面因素的路径权值函数,根据节点剩余能量的实时变化动态优化网络的拓扑结构。仿真结果表明,算法可以构建具有连通性的网络拓扑结构,与其它算法相比,能够均衡整个AdHoc网络节点的能量,显著地延长网络的寿命,从而保证网络长时间的可靠运行。     

基于动态规划的无线传感器网络的路由算法

路由问题是无线传感器网络中的核心问题之一,其数据传送的多跳特点使得非常适合用动态规划的原理来设计传感器网络的路由算法.基于动态规划,通过节点跳数生成算法为传感器网络中的每个节点赋一个表示到Sink点跳数的节点跳数值,并分析了传感器网络的拓扑结构特点,然后给出了无线传感器网络中寻找从源到汇满足不同设计目标的最小跳数(MinH)、最小跳数最大剩余能量(MinHMaxRE)和最小跳数最小费用(MinHMinC)3种路由算法.探讨了最小跳数最小费用路由与最小费用路由之间的关系,并给出了判断最小跳数最小费用路径就是最小费用路径的一个充要条件.算法的能量消耗分析表明,所给路由算法能实现大幅度的能量节省.