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International Conference on Networked Sensing Systems

作者： Liang Cheng Shamim N. Pakzad Department of Computer Science and Engineering Lehigh University Department of Civil and Environmental Engineering Lehigh University

ISBN: (纸本)9781424463138;9781424463145

Applying wireless sensor networks (WSNs) for bridge monitoring has received considerable interests over the past few years. In this paper two WSN-agility problems are identified based on the deployment experiences of WSNs in earthquake monitoring of bridges: (i) timely capturing the earthquake response of bridges and (ii) quasi-realtime processing of the measured data for bridge modal identification in monitoring the features of the structure. This paper also presents solutions for these problems: a pulse-based media access control scheme for the first problem and a distributed approach to modal identification by spectral methods for the second problem to address the combined agility issues. Results show the effectiveness of the proposed approaches.

关键词： Wireless sensor networks Network agility Media access control Modal identification distributed algorithm Modal identification Wireless sensor networks seismic networks Medium access control bridges distributed algorithms agility

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Simultaneous Optimization for Dynamic Sensor Function Allocation and Effective Sensed Data Aggregation in Wireless Sensor Networks

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INTERNATIONAL JOURNAL OF FUTURE GENERATION COMMUNICATION AND NETWORKING 2009年第4期2卷 15-27页

作者： Kawano, Ryouhei Miyazaki, Toshiaki Univ Aizu Grad Sch Comp Sci & Engn Aizu Wakamatsu Fukushima 9658580 Japan

This paper proposes a method to realize sensor function allocation and effective data aggregation simultaneously in wireless sensor networks. This method realizes dynamic allocation of sensor functions so as to balance the distribution of each sensor function in a target monitoring area. In addition, effective data aggregation is performed by using a tree network topology and time division multiple access (TDMA), which is a collision-free communication scheme. By comparing the results from the proposed method with the results from non-optimized methods, it can be validated that the proposed method is 1.7 times more efficient than non-optimized methods in distributing sensor functions. With this method, the network lifetime is doubled, and the number of data packets received at a base station is considerably increased by avoiding packet collisions.

关键词： Resource Balancing TDMA distributed algorithm Graph Coloring

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distributed algorithm of certificate revocation for Ad Hoc network

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Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University 2005年第2期29卷 44-46+68页

作者： Ning, Hong-Zhou Liu, Yun He, De-Quan Sch. of Electron. and Info. Eng. Beijing Jiaotong Univ. Beijing 100044 China

After analyzing the problem of security infrastructure of ad hoc network, a distributed algorithm of certificate revocation for ad hoc network is presented. In the algorithm, certificate revocation is parted into unconditional revocation and conditional revocation. With using revoking matrix (T) and weight vector W(T) to describe revoking relationship and creditability of network nodes, a revoking effect factor a is introduced to limit revoking strength of single node and increase united revoking strength in order to improve reliability of revoking. By using iterative equation of node weight, the node weight is updated continuously in network running. Finally, the reliability of the distributed algorithm of certificate revocation, the value of the revoking effect factor α and its effect on certificate revocation are analyzed quantitatively.

关键词： Ad Hoc network Certificate revocation algorithm distributed algorithm

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distributed localization for anchor-free sensor networks

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Journal of Systems Engineering and Electronics 2008年第3期19卷 405-418页

作者： Cui Xunxue Shan Zhiguan Liu Jianjun New Star Research Inst. of Applied Technology Hefei 230031 P. R. China Dept. of Informatization Research State Information Center Beijing 100045 P. R. China

Geographic location of nodes is very useful in a sensor network. Previous localization algorithms assume that there exist some anchor nodes in this kind of network, and then other nodes are estimated to create their coordinates. Once there are not anchors to be deployed, those localization algorithms will be invalidated. Many papers in this field focus on anchor-based solutions. The use of anchors introduces many limitations, since anchors require external equipments such as global position system, cause additional power consumption. A novel positioning algorithm is proposed to use a virtual coordinate system based on a new concept--virtual anchor. It is executed in a distributed fashion according to the connectivity of a node and the measured distances to its neighbors. Both the adjacent member information and the ranging distance result are combined to generate the estimated position of a network, one of which is independently adopted for localization previously. At the position refinement stage the intermediate estimation of a node begins to be evaluated on its reliability for position mutation; thus the positioning optimization process of the whole network is avoided falling into a local optimal solution. Simulation results prove that the algorithm can resolve the distributed localization problem for anchor-free sensor networks, and is superior to previous methods in terms of its positioning capability under a variety of circumstances.

关键词： anchor-free localization distributed algorithm position estimation sensor networks.

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distributed spectrum management algorithms for multiuser DSL networks

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2008年第10期56卷 4825-4843页

作者： Tsiaflakis, Paschalis Diehl, Moritz Moonen, Marc Katholieke Univ Leuven Dept Elect Engn ESAT SISTA B-3001 Louvain Belgium Katholieke Univ Leuven Dept Elect Engn ESAT OPTEC B-3001 Louvain Belgium

Modern digital subscriber line (DSL) networks suffer from crosstalk among different lines in the same cable bundle. This crosstalk can lead to a major performance degradation. By balancing the transmit power spectra, the impact of crosstalk can be minimized leading to spectacular performance gains. This is referred to as spectrum management. In this paper, a unifying perspective is presented on distributed spectrum management algorithms based on the Karush-Kuhn-Tucker (KKT) conditions. Furthermore, novel distributed algorithms are presented within the same KKT framework. The proposed distributed algorithms consist of local water-filling-like algorithms running in the individual modems, controlled by the spectrum management center. Extensive simulation results show that the proposed algorithms perform very well for several multi-user ADSL and VDSL scenarios.

关键词： digital subscriber line (DSL) distributed algorithm interference channel Karush-Kuhn-Tucker (KKT) multicarrier power allocation spectrum management

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distributed Downlink Beamforming With Cooperative Base Stations

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IEEE TRANSACTIONS ON INFORMATION THEORY 2008年第12期54卷 5491-5499页

作者： Ng, Boon Loong Evans, Jamie S. Hanly, Stephen V. Aktas, Defne Univ Melbourne Dept Elect & Elect Engn ARC Special Res CUBIN Melbourne Vic 3010 Australia Bilkent Univ Dept Elect & Elect Engn TR-06800 Ankara Turkey

In this paper, we consider multicell processing on the downlink of a cellular network to accomplish "macrodiversity" transmit beamforming. The particular downlink beamformer structure we consider allows at recasting of the downlink beamforming problem as a virtual linear mean square error (LMMSE) estimation problem. We exploit the structure of the channel and develop distributed beamforming algorithms using local message passing between neighboring base stations. For 1-D networks, we use the Kalman smoothing framework to obtain a forward-backward beamforming algorithm. We also propose a limited extent version or this algorithm that shows that the delay need not grow with the size of the network in practice. For 2-D cellular networks, we remodel the network as a factor graph and present it distributed beamforming algorithm based on the sum-product algorithm. Despite the presence of loops in the factor graph, the algorithm produces optimal results if convergence occurs.

关键词： Cooperative base stations distributed algorithm downlink beamforming Kalman smoothing linear mean square error (LMMSE) localized interference message passing multicell processing multiple-input-multiple-output (MIMO) sum-product algorithm

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distributed Uplink Power Control for Optimal SIR Assignment in Cellular Data Networks

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IEEE-ACM TRANSACTIONS ON NETWORKING 2008年第6期16卷 1420-1433页

作者： Hande, Prashanth Rangan, Sundeep Chiang, Mung Wu, Xinzhou Princeton Univ Dept Elect Engn Princeton NJ 08544 USA Qualcomm Flar Technol Bedminster NJ 07921 USA Qualcomm Flar Technol Bridgewater NJ 08807 USA

This paper solves the joint power control and SIR assignment problem through distributed algorithms in the uplink of multi-cellular wireless networks. The 1993 Foschini-Miljanic distributed power control can attain a given fixed and feasible SIR target. In data networks, however, SIR needs to be jointly optimized with transmit powers in wireless data networks. In the vast research literature since the mid-1990s, solutions to this joint optimization problem are either distributed but suboptimal, or optimal but centralized. For convex formulations of this problem, we report a distributed and optimal algorithm. The main issue that has been the research bottleneck is the complicated, coupled constraint set, and we resolve it through a re-parametrization via the left Perron Frobenius eigenvectors, followed by development of a locally computable ascent direction. A key step is a new characterization of the feasible SIR region in terms of the loads on the base stations, and an indication of the potential interference from mobile stations, which we term spillage. Based on this load-spillage characterization, we first develop a distributed algorithm that can achieve any Pareto-optimal SIR assignment, then a distributed algorithm that picks out a particular Pareto-optimal SIR assignment and the associated powers through utility maximization. Extensions to power-constrained and interference-constrained cases are carried out. The algorithms are theoretically sound and practically implementable: we present convergence and optimality proofs as well as simulations using 3GPP network and path loss models.

关键词： Cellular networks distributed algorithm optimization power control wireless networks

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Time-efficient distributed layer-2 auto-configuration for cognitive radio networks

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COMPUTER NETWORKS 2008年第4期52卷 831-849页

作者： Krishnamurthy, Srinivasan Thoppian, Mansi Kuppa, Srikant Chandrasekaran, R. Mittal, Neeraj Venkatesan, S. Prakash, Ravi Univ Texas Dallas Erik Jonsson Sch Engn & Comp Sci Richardson TX 75083 USA

Cognitive radios (CR) have the ability to dynamically adapt to local spectrum availability. In a network comprised of CR-enabled devices, layer-2 auto-configuration involves determining a common set of channels to facilitate communication among participating nodes. This is a unique challenge as nodes in the CR network may be unaware of (a) their neighbors and (b) the channels on which they can communicate with a neighbor. In this paper, we propose a time-efficient distributed algorithm for layer-2 auto-configuration for a CR network. Our algorithm finds the globally common channel set in 2MN + O(DN) timeslots, where each node is assigned a unique identifier from the range [1, ..., N], M is the maximum number of channels available for communication, and D is the diameter of the network. All nodes know M and N. We present both diameter-aware and diameter-unaware versions of the algorithm. We then show that the proposed algorithms are efficient by proving a rnatching lower bound. Finally, we investigate a special case when nodes have more knowledge available at their disposal and discuss how the time-complexity of our algorithm can be improved under this case. (C) 2007 Elsevier B.V. All rights reserved.

关键词： cognitive radio multiple channels neighbor discovery distributed algorithm

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distributed reformation of core-based group-shared multicast trees in mobile ad hoc networks

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JOURNAL OF PARALLEL AND distributed COMPUTING 2008年第5期68卷 582-595页

作者： Liu, Bing-Hong Huang, Ping-Chin Tsai, Ming-Jer Natl Tsing Hua Univ Dept Comp Sci Hsinchu Taiwan

This paper proposes a method to reduce the cost of a core-based group-shared multicast tree, where the cost is evaluated by the total bandwidth consumption of multicasting packets among all group members. Due to the broadcast nature of radio transmissions, we find that the challenge of determining minimum cost multicast tree can be approximated by finding the multicast tree with a minimum number of non-leaves (the minimum non-leaf multicast tree problem). However, we also find that the minimum non-leaf multicast tree problem is NP-complete. Thus, a method is proposed to dynamically reduce the number of non-leaves in an existing multicast tree. Experimental results show that our method reduces the cost of the multicast tree in both geometrically and randomly distributed network models and the random waypoint mobility model. (C) 2007 Elsevier Inc. All rights reserved.

关键词： multicast distributed algorithm mobile computing bandwidth consumption network topology

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A distributed framework for correlated data gathering in sensor networks

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2008年第1期57卷 578-593页

作者： Yuen, Kevin Liang, Ben Li, Baochun Univ Toronto Dept Elect & Comp Engn Toronto ON M5S 3G4 Canada

We consider the problem of correlated data gathering in sensor networks with multiple sink nodes. The problem has two objectives. First, we would like to find a rate allocation on the correlated sensor nodes such that the data gathered by the sink nodes can reproduce the field of observation. Second, we would like to find a transmission structure on the network graph such that the total transmission energy consumed by the network is minimized. The existing solutions to this problem are impractical for deployment because they have not considered all of the following factors: 1) distributed implementation;2) capacity and interference associated with the shared medium;and 3) realistic data correlation model. In this paper, we propose a new distributed framework to achieve minimum energy data gathering while considering these three factors. Based on a localized version of Slepian-Wolf coding, the problem is modeled as an optimization formulation with a distributed solution. The formulation is first relaxed with Lagrangian dualization and then solved with the sub-gradient algorithm. The algorithm is amenable to fully distributed implementations, which corresponds to the decentralized nature of sensor networks. To evaluate its effectiveness, we have conducted extensive simulations under a variety of network environments. The results indicate that the algorithm supports asynchronous network settings, sink mobility, and duty schedules.

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