Energy-efficient bootstrapping for wireless sensor networks

Wireless sensor networks are poised for increasingly wider uses in many military and civil applications. Such applications has stimulated research in a number of research areas related to energy conservation in such networks. Most such research focuses on energy saving in tasks after the network has been organized. Very little attention has been paid to network bootstrapping as a possible phase where energy can be saved. Bootstrapping is the phase in which the entities in a network are made aware of the presence of all or some of the other entities in the network. This paper describes a bootstrapping protocol for a class of sensor networks consisting of a mix of low-energy sensor nodes and a small number of high-energy entities called gateways. We propose a new approach, namely the slotted sensor bootstrapping (SSB) protocol, which focuses on avoiding collisions in the bootstrapping phase and emphasizes turning off node radio circuits whenever possible to save energy. Our mechanism synchronizes the sensor nodes to the gateway’s clock so that time-based communication can be used. The proposed SSB protocol tackles the issue of node coverage in scenarios, when physical device limitations and security precautions prevent some sensor nodes from communicating with the gateways. Additionally, we present an extension of the bootstrapping protocol, which leverages possible gateway mobility.     

无线传感器网络中的能效优化路由算法*

根据无线传感器网络节点能量消耗和网络生存周期的特点,通过建立动态规划能量优化模型,在路由总能耗满足能量阈值约束条件下,均衡消耗网络中各节点能量,在此基础上提出一种适合无线传感器网络的动态规划路由算法。仿真结果表明,提出的路由算法能充分地利用有限的能量资源,较大地延长网络生存周期并降低节点的平均能耗。     

一种异构传感器网络下的节能分簇路由算法

无线传感器网络存在着严重的能量约束,传统同构的传感网络路由协议和算法不适合异构网络,因此,设计异构传感网络下的节能路由算法具有现实意义。研究两种不同类型传感器节点构成的,具有不同的初始能量和不同感知数据能力的异构网络中基于簇头预测的节能分簇路由算法ECAH。根据簇内节点的剩余能量、能量消耗速率和跟上一轮簇头的距离预测出下一轮簇头,有效地减少了控制报文数量,降低了系统开销,节约了能量。仿真结果显示,在异构的网络中采用ECAH路由算法比LEACH算法网络生存时间大约提高了23%。     

Energy-efficient forwarding in wireless sensor networks

For maximizing the energy efficiency in a wireless network, we propose two forwarding schemes termed single-link and multi-link energy-efficient forwarding that tradeoff delivery ratios against energy costs. Multi-link forwarding improves the network performance substantially by addressing multiple receivers at once during the packet forwarding process. If the first forwarding node does not receive a packet correctly, other nodes may act as backup nodes and perform the forwarding instead. By means of mathematical analyses, we derive how the energy efficiency of a forwarding path can be computed and how a forwarding tree is established. Routing cycles are explicitly taken into account and prevented by means of sequence numbers. Simulations and real-world experiments provide a comparison to other reference strategies, showing a superior performance of our forwarding scheme in terms of energy efficiency.     

高效节能的链式分层无线传感器网络路由协议

提出了一种高效节能的链式分层无线传感器网络路由协议（ECR）,阐述了协议的组织思想。本协议采用混合控制方式,有效结合中心控制方式和分布式算法的优势,产生两层链式簇结构;利用简单而高效的最大剩余能量原则选取父簇头,有效延长了网络第一个节点失效的时间和提高了网络能量利用率。通过与LEACH和PEGASIS 两协议的仿真比较,论证了ECR协议的高效性。     

Energy-efficient cooperative data aggregation for wireless sensor networks

Recently, cooperative communication mechanism is shown to be a promising technology to improve the transmit diversity only by a single transceiver antenna. Using this communication paradigm, multiple source nodes are able to coordinate their transmissions so as to obtain energy savings. As data aggregation is one of the most important operations in wireless sensor networks, this paper studies the energy-efficient data aggregation problem through cooperative communication. We first define the cooperative data aggregation (CDA) problem, and formally prove that this problem is NP-Hard. Due to the difficult nature of this problem, we propose a heuristic algorithm MCT for cooperative data aggregation. The theoretical analysis shows that this algorithm can reach the approximate performance ratio of 2. Moreover, the distributed implementation DMCT of the algorithm is also described. We prove that both centralized and distributed algorithms can construct the same topology for cooperative data aggregation. The experimental simulations show that the proposed algorithms will decrease the power consumption by about 12.5% and 66.3% compared with PEDAP and PEGASIS algorithms respectively.     

无线传感网中能量有效的免碰撞MAC协议

无线传感网络普遍使用CSMA/CA机制和二进制指数退避算法避免碰撞。提出了一种能量有效的免碰撞MAC协议ERC。该协议将数据传输划分为协商和节点排队传输两个阶段,通过碰撞避免、节点休眠和批量传输机制提升吞吐量并节省整体能耗。理论分析和仿真表明,该协议在各种负载情况下都能明显提升网络的吞吐量与能量效率。     

Energy-efficient adaptive sensor scheduling for target tracking in wireless sensor networks

Sensor scheduling is essential to collaborative target tracking in wireless sensor networks (WSNs). In the existing works for target tracking in WSNs, such as the information-driven sensor query (IDSQ), the tasking sensors are scheduled to maximize the information gain while minimizing the resource cost based on the uniform sampling intervals, ignoring the changing of the target dynamics and the specific desirable tracking goals. This paper proposes a novel energyefficient adaptive sensor scheduling approach that jointly selects tasking sensors and determines their associated sampling intervals according to the predicted tracking accuracy and tracking energy cost. At each time step, the sensors are scheduled in alternative tracking mode, namely, the fast tracking mode with smallest sampling interval or the tracking maintenance mode with larger sampling interval, according to a specified tracking error threshold. The approach employs an extended Kalman filter (EKF)-based estimation technique to predict the tracking accuracy and adopts an energy consumption model to predict the energy cost. Simulation results demonstrate that, compared to a non-adaptive sensor scheduling approach, the proposed approach can save energy cost significantly without degrading the tracking accuracy.     

Energy-efficient filtering for skyline queries in cluster-based sensor networks

Filtering is a generic technique for skyline retrieval in sensor networks, for the purpose of reducing the communication cost, the dominant part of energy consumption. The vast majority of existing filtering approaches are suitable for uniform and correlated datasets, whereas in many applications the data distribution is clustered or anti-correlated. The only work considering anti-correlated dataset requires significant energy for filtering construction, and it is hard to be efficiently adapted to clustered databases. In this paper, we propose a new filtering algorithm, which settles the problem by utilizing individual node characteristics and generating personalized filters. Given a fraction k, a personalized filter prunes at least k percent of points on assigned nodes. A novel scheme for data cluster representation and a sampling method are then proposed to reduce the filtering cost and maximize the benefit of filtering. Extensive simulation results show the superiority of our approach over existing techniques.     

多级能量异构传感器网络能量有效的路由算法

能量异构在无线传感器网络中普遍存在,由于多级能量异构无线传感器网络节点的初始能量在一定范围内随机分布,为了能有效地利用节点能量的异构性降低网络能耗、延长网络稳定周期,提出一种适用于能量异构环境的多级能量异构传感器网络能量有效的路由算法。节点根据其当前剩余能量与网络平均能量的比值决定其成为簇首的概率,通过调整节点的阈值,并基于此决定是否成为簇首,且在簇间采用多跳路由协议。仿真结果表明多级能量异构传感器网络能量有效的路由算法可以有效地均衡网络能量消耗,延长网络稳定周期。     

带状无线传感器网络能量高效的节点部署策略

带状无线传感器网络具有特殊的拓扑结构,满足很多重要领域的应用需求。针对带状网络中的能量消耗不均衡问题,分析了带状无线传感器网络在多跳通信时的拓扑结构和能耗模型,在对带状网络进行分簇的基础上,提出一种非均匀的节点部署策略,该策略量化了带状传感器网络中簇内节点的数目关系,并设计了相应的路由协议。仿真结果表明,非均匀的节点部署策略可以缓解带状网络的能量空洞问题,使网络能耗趋于均衡,延长整个网络的生命周期。     

一种低能耗低延时的无线传感器网络MAC协议

传感器网络中数据从多个源节点向sink节点的转发形成数据汇集树,针对此汇集树提出低能耗低延时的LD MAC（Low Delay MAC）协议,解决以往MAC协议中能耗和延时的矛盾问题。LD MAC一方面采用异步duty cycle机制降低能耗,另一方面,从源到sink节点的转发路径上的节点逐个推迟帧的发送起始时间,依次进行接收与发送,减少数据在传输过程中的延时。分析和实验表明LD MAC较好地解决了能耗和延时的矛盾问题。     

节能高效的无线传感器网络非均匀分簇路由协议

为了有效均衡无线传感器网络能耗、缓解能量洞问题、延长网络生命周期,提出了一种节能高效的非均匀分簇路由协议,其核心思想是采用结合计时广播和簇头轮换机制的非均匀分簇（BR—EEUC）算法对网络分簇,并根据代价函数选择代价较低的簇头作为中继节点,形成以汇聚节点为根节点的多跳路由,从而大大降低了能量开销。通过在OMNet＋＋平台上的仿真实验结果表明：与LEACH和EEUC等路由协议相比,该协议有效地均衡了网络能量消耗,延长了网络寿命。     

Energy-efficient deployment of Intelligent Mobile sensor networks

Many visions of the future include people immersed in an environment surrounded by sensors and intelligent devices, which use smart infrastructures to improve the quality of life and safety in emergency situations. Ubiquitous communication enables these sensors or intelligent devices to communicate with each other and the user or a decision maker by means of ad hoc wireless networking. Organization and optimization of network resources are essential to provide ubiquitous communication for a longer duration in large-scale networks and are helpful to migrate intelligence from higher and remote levels to lower and local levels. In this paper, distributed energy-efficient deployment algorithms for mobile sensors and intelligent devices that form an Ambient Intelligent network are proposed. These algorithms employ a synergistic combination of cluster structuring and a peer-to-peer deployment scheme. An energy-efficient deployment algorithm based on Voronoi diagrams is also proposed here. Performance of our algorithms is evaluated in terms of coverage, uniformity, and time and distance traveled until the algorithm converges. Our algorithms are shown to exhibit excellent performance.     

一种能量高效的无线传感器网络分簇路由算法

无线传感器网络中节点的能量有限,提高能量的有效性便成为无线传感器网络路由协议设计的首要目标。设计了一种能量高效的分簇路由算法,它提出让候选节点在一定的覆盖范围内以剩余能量为标准来竞选簇头,以使簇头分布均匀;处于簇类交界的节点则根据能量和距离来选择归属的簇头,以平衡网络负载;新算法还采用多跳的簇间通信方式来降低大部分簇头节点的通信负载。仿真结果表明:新算法能够有效降低网络能耗,延长网络生存时间。     

Energy-efficient communication in wireless cable sensor networks

In this paper, we introduce a new type of sensor: cable sensor. Unlike traditional point sensors, this type of sensor has a rectangular sensing region with a processor installed on it to do processing and communication. The wireless network formed by this kind of sensor is called wireless cable sensor network (WCSN). We study energy-efficient communication algorithms in WCSNs. We address it in two ways: one is through reducing the total transmission power of processors while maintaining the connectivity of the network and the other is through scheduling cable sensors to let them take turns to go to sleep without affecting the coverage and connectivity of the network. In the first approach, we initially develop a distributed algorithm called DTRNG based on the relative neighbourhood graph. Later we enhance it to Algorithm determine the transmission power by removing the largest edge in CYCles (DTCYC). Mathematical proofs show that Algorithm DTCYC provides an optimal solution that can not only minimise the total processor transmission power but maintain the connectivity of the network as well. In the second approach, we propose a cable mode transition algorithm which determines the minimum number of active sensors to maintain K-coverage as well as K-connectivity required by the application. We discuss the relationship between coverage and connectivity and prove the theorems that lay the foundation for our algorithm. Simulation results demonstrate that our algorithm is efficient in saving energy.     

Energy-efficient distributed clustering in wireless sensor networks

The deployment of wireless sensor networks in many application areas requires self-organization of the network nodes into clusters. Clustering is a network management technique, since it creates a hierarchical structure over a flat network. Quite a lot of node clustering techniques have appeared in the literature, and roughly fall into two families: those based on the construction of a dominating set and those which are based solely on energy considerations. The former family suffers from the fact that only a small subset of the network nodes are responsible for relaying the messages, and thus cause rapid consumption of the energy of these nodes. The latter family uses the residual energy of each node in order to decide about whether it will elect itself as a leader of a cluster or not. This family’s methods ignore topological features of the nodes and are used in combination with the methods of the former family. We propose an energy-efficient distributed clustering protocol for wireless sensor networks, based on a metric for characterizing the significance of a node, w.r.t. its contribution in relaying messages. The protocol achieves small communication complexity and linear computation complexity. Experimental results attest that the protocol improves network longevity.     

Energy-efficient clustering in lossy wireless sensor networks

Recent experimental studies have revealed that a large percentage of wireless links are lossy and unreliable for data delivery in wireless sensor networks (WSNs). Such findings raise new challenges for the design of clustering algorithms in WSNs in terms of data reliability and energy efficiency. In this paper, we propose distributed clustering algorithms for lossy WSNs with a mobile collector, where the mobile collector moves close to each cluster head to receive data directly and then uploads collected data to the base station. We first consider constructing one-hop clusters in lossy WSNs where all cluster members are within the direct communication range of their cluster heads. We formulate the problem into an integer program, aiming at maximizing the network lifetime, which is defined as the number of rounds of data collection until the first node dies. We then prove that the problem is NP-hard. After that, we propose a metric-based distributed clustering algorithm to solve the problem. We adopt a metric called selection weight for each sensor node that indicates both link qualities around the node and its capability of being a cluster head. We further extend the algorithm to multi-hop clustering to achieve better scalability. We have found out that the performance of the one-hop clustering algorithm in small WSNs is very close to the optimal results obtained by mathematical tools. We have conducted extensive simulations for large WSNs and the results demonstrate that the proposed clustering algorithms can significantly improve the data reception ratio, reduce the total energy consumption in the network and prolong network lifetime compared to a typical distributed clustering algorithm, HEED, that does not consider lossy links.     

.应用于中等负载无线传感器网络的节能型MAC协议

基于网络负载的大小,提出了适用于中等负载的无线传感器网络的节能MAC协议——EC-MAC协议。该协议引入概率p,采用TDMA方式和减少节点的空闲侦听时间来节能,提高了信道的利用率,延长了网络的生命周期。仿真结果表明,该协议在节省能量方面要优于传统TDMA和BMA协议。     

高效节能的无线传感器网络数据收集协议*

现有的数据收集协议的性能不是很好,为此提出了一种基于数据收集树的数据收集协议。它通过减少数据收集树中的节点深度和中间节点数来减少制约系统生命期的节点传输数据给基站的能量消耗和节点空闲侦听的能量消耗。仿真实验表明,该协议能将系统生命期延长36%左右。