Results 1 - 10 of 44

Exploring link correlation for efficient flooding in wireless sensor networks

by Ting Zhu, Ziguo Zhong, Tian He, Zhi-li Zhang - In NSDI ’10
"... Existing flooding algorithms have demonstrated their effectiveness in achieving communication efficiency and reliability in wireless sensor networks. However, further performance improvement has been hampered by the assumption of link independence, a design premise imposing the need for costly ackno ..."
Abstract - Cited by 28 (11 self) - Add to MetaCart
Existing flooding algorithms have demonstrated their effectiveness in achieving communication efficiency and reliability in wireless sensor networks. However, further performance improvement has been hampered by the assumption of link independence, a design premise imposing the need for costly acknowledgements (ACKs) from every receiver. In this paper, we present Collective Flooding (CF), which exploits thelinkcorrelation to achieve flooding reliability using the concept of collective ACKs. CF requires only 1-hop information from a sender, making the design highly distributed and scalable with low complexity. We evaluate CF extensively in realworld settings, using three different types of testbeds: a single hop network with 20 MICAz nodes, a multihop network with 37 nodes, and a linear outdoor network with 48 nodes along a 326-meter-long bridge. System evaluation and extensive simulation show that CF achieves the same reliability as the state-of-the art solutions, while reducing the total number of packet transmission and dissemination delay by 30 ∼ 50 % and 35 ∼ 50%, respectively. 1
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Exploiting Constructive Interference for Scalable Flooding in Wireless Networks

by Yin Wang, Yuan He, Xufei Mao, Yunhao Liu, Zhiyu Huang, Xiangyang Li
"... Abstract—Exploiting constructive interference in wireless networks is an emerging trend for it allows multiple senders transmit an identical packet simultaneously. Constructive interference based flooding can realize millisecond network flooding latency and sub-microsecond time synchronization accur ..."
Abstract - Cited by 23 (4 self) - Add to MetaCart
Abstract—Exploiting constructive interference in wireless networks is an emerging trend for it allows multiple senders transmit an identical packet simultaneously. Constructive interference based flooding can realize millisecond network flooding latency and sub-microsecond time synchronization accuracy, require no network state information and adapt to topology changes. However, constructive interference has a precondition to function, namely, the maximum temporal displacement ∆ of concurrent packet transmissions should be less than a given hardware constrained threshold. We disclose that constructive interference based flooding suffers the scalability problem. The packet reception performances of intermediate nodes degrade significantly as the density or the size of the network increases. We theoretically show that constructive interference based flooding has a packet reception ratio (PRR) lower bound (95.4%) in the grid topology. For a general topology, we propose the spine constructive interference based flooding (SCIF) protocol. With little overhead, SCIF floods the entire network much more reliably than Glossy [1] in high density or large-scale networks. Extensive simulations illustrate that the PRR of SCIF keeps stable above 96 % as the network size grows from 400 to 4000 while the PRR of Glossy is only 26 % when the size of the network is 4000. We also propose to use waveform analysis to explain the root cause of constructive interference, which is mainly examined in simulations and experiments. We further derive the closed-form PRR formula and define interference gain factor (IGF) to quantitatively measure constructive interference. I.
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On Multihop Broadcast over Adaptively DutyCycled Wireless Sensor Networks

by Shouwen Lai, Binoy Ravindran - in DCOSS’10 , 2010
"... Abstract. We consider the problem of multihop broadcast over adap-tively duty-cycled wireless sensor networks (WSNs) where neighborhood nodes are not simultaneously awake. We present Hybrid-cast, an asyn-chronous and multihop broadcasting protocol, which can be applied to low duty-cycling or quorum- ..."
Abstract - Cited by 9 (0 self) - Add to MetaCart
Abstract. We consider the problem of multihop broadcast over adap-tively duty-cycled wireless sensor networks (WSNs) where neighborhood nodes are not simultaneously awake. We present Hybrid-cast, an asyn-chronous and multihop broadcasting protocol, which can be applied to low duty-cycling or quorum-based duty-cycling schedule where nodes send out a beacon message at the beginning of wakeup slots. Hybrid-cast achieves better tradeoff between broadcast latency and broadcast count compared to previous broadcast solutions. It adopts opportunis-tic data delivery in order to reduce the broadcast latency. Meanwhile, it reduces redundant transmission via delivery deferring and online for-warder selection. We establish the upper bound of broadcast count and the broadcast latency for a given duty-cycling schedule. We evaluate Hybrid-cast through extensive simulations. The results validate the ef-fectiveness and efficiency of our design. 1
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ERN: Emergence Rescue Navigation with Wireless Sensor Networks

by Shen Li, Andong Zhan, Xiaobing Wu, Guihai Chen - 15TH INTERNATIONAL CONFERENCE ON PARALLEL AND DISTRIBUTED SYSTEMS , 2009
"... Navigation with wireless sensor networks (WSNs) can help people escape safely from an emergency. Previous navigation algorithms attempt to find safe and efficient escape paths for individuals under various environmental dynamics but ignore possible congestion caused by the individuals rushing for th ..."
Abstract - Cited by 9 (2 self) - Add to MetaCart
Navigation with wireless sensor networks (WSNs) can help people escape safely from an emergency. Previous navigation algorithms attempt to find safe and efficient escape paths for individuals under various environmental dynamics but ignore possible congestion caused by the individuals rushing for the exits. Moreover, all the previous works have overlooked the fact that the emergency rescue force can take actions strategically in order to save people out of danger. We propose ERN, Emergence Rescue Navigation algorithm by treating WSNs as navigation infrastructure. ERN takes both pedestrian congestion and rescue force flexibility into account. A directed graph is used to model the emergency regions. Human’s movements are regarded as network flows on the graph. By calculating the maximum flow and minimum cut on the graph, the system can provide firemen rescue commands to eliminate key dangerous areas, which may significantly reduce congestion and save trapped people. We have performed extensive simulations under dynamic environments to evaluate the effectiveness and response time of ERN. Simulation results show that with ERN people in emergency are evacuated much faster and less congestion is observed.

Energy management in sensor networks

by A. Stankovic, Tian He - Phil. Trans. R. Soc , 2011
"... doi:10.1098/rsta.2011.0195 ..."
Abstract - Cited by 8 (0 self) - Add to MetaCart
doi:10.1098/rsta.2011.0195

Leveraging IP for Sensor Network Deployment

by Simon Duquennoy, Niklas Wirström, Nicolas Tsiftes, Adam Dunkels - In Proceedings of the workshop on Extending the Internet to Low power and Lossy Networks (IP+SN 2011 , 2011
"... Ease of deployment has always been seen as a major selling point of wireless sensor networks, yet experience has shown deployment to be difficult. We argue that parts of these difficulties have come from the lack of a generic networking layer and of well-tested, generic transport protocols in tradit ..."
Abstract - Cited by 6 (3 self) - Add to MetaCart
Ease of deployment has always been seen as a major selling point of wireless sensor networks, yet experience has shown deployment to be difficult. We argue that parts of these difficulties have come from the lack of a generic networking layer and of well-tested, generic transport protocols in traditional sensornet deployments. We believe that the use of low-power IPv6 can help by providing nodelevel addressing, point-to-point routing, and generic well-tested transport protocols. We evaluate the performance of HTTP/TCP and CoAP/UDP over a duty cycled radio layer, showing that with a small modification to the duty cycling layer results in a dramatic improvement in performance at a retained low power consumption. Based on our experiences, we introduce an in-network caching mechanism that significantly improves the performance of software updates in incrementally deployed sensor networks. Our results are the first steps towards a deployment tool for IP-based sensor networks. 1.
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Towards Energy-Fairness in Asynchronous Duty-Cycling Sensor Networks

by Zhenjiang Li, Mo Li, Yunhao Liu
"... Abstract—In this paper, we investigate the problem of controlling node sleep intervals so as to achieve the min-max energy fairness in asynchronous duty-cycling sensor networks. We propose a mathematical model to describe the energy efficiency of such networks and observe that traditional sleep inte ..."
Abstract - Cited by 5 (2 self) - Add to MetaCart
Abstract—In this paper, we investigate the problem of controlling node sleep intervals so as to achieve the min-max energy fairness in asynchronous duty-cycling sensor networks. We propose a mathematical model to describe the energy efficiency of such networks and observe that traditional sleep interval setting strategy, i.e., operating sensor nodes with identical sleep intervals, or intuitive control heuristics, i.e., greedily increasing sleep intervals of sensor nodes with high energy consumption rates, hardly perform well in practice. There is an urgent need to develop an efficient sleep interval control strategy for achieving fair and high energy efficiency. To this end, we theoretically formulate the Sleep Interval Control (SIC) problem and find it a convex optimization problem. By utilizing the convex property, we decompose the original problem and propose a distributed algorithm, called GDSIC. In GDSIC, sensor nodes can tune sleep intervals through a local information exchange such that the maximum energy consumption rate in the network approaches to be minimized. The algorithm is self-adjustable to the traffic load variance and is able to serve as a unified framework for a variety of asynchronous duty-cycling MAC protocols. We implement our approach in a prototype system and test its feasibility and applicability on a 50-node testbed. We further conduct extensive trace-driven simulations to examine the efficiency and scalability of our algorithm with various settings. I.

Multiple Task Scheduling for Low-Duty-Cycled Wireless Sensor Networks

by Shuguang Xiong, Jianzhong Li, Mo Li, Jiliang Wang, Yunhao Liu
"... Abstract—For energy conservation, a wireless sensor network is usually designed to work in a low-duty-cycle mode, in which a sensor node keeps active for a small percentage of time during its working period. In applications where there are multiple data delivery tasks with high data rates and time c ..."
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Abstract—For energy conservation, a wireless sensor network is usually designed to work in a low-duty-cycle mode, in which a sensor node keeps active for a small percentage of time during its working period. In applications where there are multiple data delivery tasks with high data rates and time constraints, low-duty-cycle working mode may cause severe transmission congestion and data loss. In order to alleviate congestion and reduce data loss, the tasks need to be carefully scheduled to balance the workloads among the sensor nodes in both spatial and temporal dimensions. This paper studies the load balancing problem, and proves it is NP-Complete in general network graphs. Two efficient scheduling algorithms to achieve load balance are proposed and analyzed. Furthermore, a task scheduling protocol is designed relying on the proposed algorithms. To the best of our knowledge, this paper is the first one to tackle multiple task scheduling for low-duty-cycled sensor networks. The simulation results show that the proposed algorithms greatly improve the network performance in most scenarios. I.
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Duty-cycle-aware minimum-energy multicasting in wireless sensor networks

by Kai Han, Yang Liu, Jun Luo - IEEE/ACM Trans. on Networking
"... Abstract—In duty-cycled wireless sensor networks, the nodes switch between active and dormant states, and each node may determine its active/dormant schedule independently. This complicates the Minimum-Energy Multicasting (MEM) problem, which has been primarily studied in always-active wireless ad-h ..."
Abstract - Cited by 4 (2 self) - Add to MetaCart
Abstract—In duty-cycled wireless sensor networks, the nodes switch between active and dormant states, and each node may determine its active/dormant schedule independently. This complicates the Minimum-Energy Multicasting (MEM) problem, which has been primarily studied in always-active wireless ad-hoc networks. In this paper, we study the duty-cycle-aware MEM problem in wireless sensor networks, and we present a formu-lation of the Minimum-Energy Multicast Tree Construction and Scheduling (MEMTCS) problem. We prove that the MEMTCS problem is NP-hard, and it is unlikely to have an approximation algorithm with a performance ratio of (1 − o(1)) ln ∆, where ∆ is the maximum node degree in a network. We propose a polynomial-time approximation algorithm for the MEMTCS problem with a performance ratio of O(H( ∆ + 1)), where H(·) is the harmonic number. We also provide a distributed implementation of our algorithm. Finally, we perform extensive simulations and the results demonstrate that our algorithm significantly outperform other known algorithms in terms of both the total energy cost and the transmission redundancy. I.
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Wakeup scheduling for energy-efficient communication in opportunistic mobile networks

by Wei Gao, Qinghua Li - In Proceedings of IEEE INFOCOM , 2013
"... Abstract—Opportunistic mobile networks consist of mobile devices which only communicate when they opportunistically contact each other. Periodic contact probing is required to facilitate opportunistic communication, but seriously reduces the limited battery life of mobile devices. Current research e ..."
Abstract - Cited by 3 (1 self) - Add to MetaCart
Abstract—Opportunistic mobile networks consist of mobile devices which only communicate when they opportunistically contact each other. Periodic contact probing is required to facilitate opportunistic communication, but seriously reduces the limited battery life of mobile devices. Current research efforts on reducing energy consumption of contact probing are restricted to optimize the probing interval, but are insufficient for energy-efficient opportunistic communication. In this paper, we propose novel techniques to adaptively schedule wakeup periods of mobile nodes between their inter-contact times. A node stays asleep during inter-contact times when contact probing is unnecessary, and only wakes up when a contact with another node is likely to happen. Our approach probabilistically predicts node contacts in the future, and analytically balances between energy consumption for contact probing and performance of opportunistic communication. Extensive trace-driven simulations show that our approach significantly improves energy efficiency of opportunistic communication compared to existing schemes.
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