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51
Connected Sensor Cover: SelfOrganization of Sensor Networks for Efficient Query Execution
 MOBIHOC'03
, 2003
"... Spatial query execution is an essential functionality of a sensor network, where a query gathers sensor data within a specific geographic region. Redundancy within a sensor network can be exploited to rv uce the communication cost incurv1 in execution of such quer ies. Anyr eduction in communicatio ..."
Abstract

Cited by 110 (6 self)
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Spatial query execution is an essential functionality of a sensor network, where a query gathers sensor data within a specific geographic region. Redundancy within a sensor network can be exploited to rv uce the communication cost incurv1 in execution of such quer ies. Anyr eduction in communication cost wouldr esult in an e#cient use of the batter y ener gy, which is ver y limited in sensor s. One appr oach to r educe the communication cost of a quer y is to selfor ganize the networ# inr esponse to a quer , into a topology that involves only a small subset of the sensor s su#cient to pr ocess the quer y. The quer y is then executed using only the sensor in the constr ucted topology. In thisar icle, we design and analyze algor thms for such selfor"/0 zation of asensor networ tor educe enerP consumption. In par icular we develop the notion of a connected sensor cover and design a centr alized appr oximation algor thm that constr ucts a topology in ol ing anear optimal connected sensor co er . We pr o e that the size of the const rst ed topology is within an O(log n)factor ofthe optimal size, wher n is the networ size. We also de elop a distr ibuted selfor$1" zationer" on ofour algor thm, and prv ose seer/ optimizations tor educe the communication oer"E1 of the algorithm. Finally, we evaluate the distributed algorithm using simulations and show that our approach results in significant communication cost reduction.
Localized MinimumEnergy Broadcasting in AdHoc Networks
, 2003
"... In the minimum energy broadcasting problem, each node can adjust its transmission power in order to minimize total energy consumption but still enable a message originated from a source node to reach all the other nodes in an adhoc wireless network. In all existing solutions each node requires glob ..."
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Cited by 92 (6 self)
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In the minimum energy broadcasting problem, each node can adjust its transmission power in order to minimize total energy consumption but still enable a message originated from a source node to reach all the other nodes in an adhoc wireless network. In all existing solutions each node requires global network information (including distances between any two neighboring nodes in the network) in order to decide its own transmission radius. In this paper, we describe a new localized protocol where each node requires only the knowledge of its distance to all neighboring nodes and distances between its neighboring nodes (or, alternatively, geographic position of itself and its neighboring nodes). In addition to using only local information, our protocol is shown experimentally to be comparable to the best known globalized BIP solution. Our solutions are based on the use of relative neighborhood graph which preserves connectivity and is defined in localized manner. I.
Geometric Spanners for Wireless Ad Hoc Networks
 IEEE Transactions on Parallel and Distributed Systems
, 2003
"... We propose a new geometric spanner for static wireless ad hoc networks, which can be constructed efficiently in a localized manner. It integrates the connected dominating set and the local Delaunay graph to form a backbone of the wireless network. ..."
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Cited by 65 (16 self)
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We propose a new geometric spanner for static wireless ad hoc networks, which can be constructed efficiently in a localized manner. It integrates the connected dominating set and the local Delaunay graph to form a backbone of the wireless network.
Extended DominatingSetBased Routing in Ad Hoc Wireless Networks with Unidirectional Links
 IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS
, 2002
"... Efficient routing among a set of mobile hosts (also called nodes) is one of the most important functions in ad hoc wireless networks. Routing based on a connected dominating set is a promising approach, where the search space for a route is reduced to the nodes in the set. A set is dominating if all ..."
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Cited by 59 (14 self)
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Efficient routing among a set of mobile hosts (also called nodes) is one of the most important functions in ad hoc wireless networks. Routing based on a connected dominating set is a promising approach, where the search space for a route is reduced to the nodes in the set. A set is dominating if all the nodes in the system are either in the set or neighbors of nodes in the set. In this paper, we extend dominatingsetbased routing to networks with unidirectional links. Specifically, an efficient localized algorithm for determining a dominating and absorbant set of vertices (mobile hosts) is given and this set can be easily updated when the network topology changes dynamically. A host v is called a dominating neighbor (absorbant neighbor) of another host u if there is a directed edge from v to u (from u to v). A subset of vertices is dominating and absorbant if every vertex not in the subset has one dominating neighbor and one absorbant neighbor in the subset. The derived dominating and absorbant set exhibits good locality properties; that is, the change of a node status (dominating/dominated) affects only the status of nodes in the neighborhood. The notion of dominating and absorbant set can also be applied iteratively on the dominating and absorbant set itself, forming a hierarchy of dominating and absorbant sets. The effectiveness of our approach is confirmed and the locality of node status update is verified through simulation.
LowInterference Topology Control for Wireless Ad Hoc Networks
 ACM Wireless Networks
, 2005
"... supported by NSF CCR0311174. Abstract — Topology control has been well studied in wireless ad hoc networks. However, only a few topology control methods take into account the low interference as a goal of the methods. Some researchers tried to reduce the interference by lowering node energy consump ..."
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Cited by 57 (0 self)
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supported by NSF CCR0311174. Abstract — Topology control has been well studied in wireless ad hoc networks. However, only a few topology control methods take into account the low interference as a goal of the methods. Some researchers tried to reduce the interference by lowering node energy consumption (i.e. by reducing the transmission power) or by devising low degree topology controls, but none of those protocols can guarantee low interference. Recently, Burkhart et al. [?] proposed several methods to construct topologies whose maximum link interference is minimized while the topology is connected or is a spanner for Euclidean length. In this paper we give algorithms to construct a network topology for wireless ad hoc network such that the maximum (or average) link (or node) interference of the topology is either minimized or approximately minimized. Index Terms — Topology control, interference, wireless ad hoc networks.
Fast Distributed Algorithms for (Weakly) Connected Dominating Sets and LinearSize Skeletons (Extended Abstract)
"... Motivated by routing issues in ad hoc networks, we present polylogarithmictime distributed algorithms for two problems. Given a network, we first show how to compute connected and weakly connected dominating sets whose size is at most O(log #) times optimal, # being the maximum degree of the input ..."
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Cited by 56 (3 self)
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Motivated by routing issues in ad hoc networks, we present polylogarithmictime distributed algorithms for two problems. Given a network, we first show how to compute connected and weakly connected dominating sets whose size is at most O(log #) times optimal, # being the maximum degree of the input network. This is bestpossible if NP ] and if the processors are limited to polynomialtime computation. We then show how to construct dominating sets which satisfy the above properties, as well as the "low stretch" property that any two adjacent nodes in the network have their dominators at a distance of at most O(log n) in the network. (Given a dominating set S, a dominator of a vertex u is any v S such that the distance between u and v is at most one.) We also show our time bounds to be essentially optimal.
Border Node Retransmission Based Probabilistic Broadcast Protocols in AdHoc Networks
 Telecommunication Systems
, 2003
"... In this paper, we propose some improvements to the flooding protocols that aim to efficiently broadcast a given information through the whole adhoc network. These improvements are based on probabilistic approach and decrease the number of emitted packets and hence, the medium occupation. Indeed, it ..."
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Cited by 51 (3 self)
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In this paper, we propose some improvements to the flooding protocols that aim to efficiently broadcast a given information through the whole adhoc network. These improvements are based on probabilistic approach and decrease the number of emitted packets and hence, the medium occupation. Indeed, it is more interesting to privilege the retransmission by nodes that are located at the radio border of the sender. We observe that the distance between two nodes with full duplex communication can be approximated by comparing their neighbor lists. This leads to broadcasting schemes that do not require position or signal strength information of nodes. Moreover, proposed broadcast protocols require only knowledge of one hop neighborhood and thus need only short hello message. Such protocols are more able to support high mobility networks than protocols that need knowledge of two or more hops neighborhood and then need longer hello messages. We compare our new schemes with variable density and experiments show that the probabilistic approach is efficient.
Efficient gathering of correlated data in sensor networks
 in Proc. of ACM Intl. symposium on Mobile ad hoc networking and computing, 2005
, 2005
"... In this paper, we design techniques that exploit data correlations in sensor data to minimize communication costs (and hence, energy costs) incurred during data gathering in a sensor network. Our proposed approach is to select a small subset of sensor nodes that may be sufficient to reconstruct data ..."
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Cited by 38 (0 self)
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In this paper, we design techniques that exploit data correlations in sensor data to minimize communication costs (and hence, energy costs) incurred during data gathering in a sensor network. Our proposed approach is to select a small subset of sensor nodes that may be sufficient to reconstruct data for the entire sensor network. Then, during data gathering only the selected sensors need to be involved in communication. The selected set of sensors must also be connected, since they need to relay data to the datagathering node. We define the problem of selecting such a set of sensors as the connected correlationdominating set problem, and formulate it in terms of an appropriately defined correlation structure that captures general data correlations in a sensor network. We develop a set of energyefficient distributed algorithms and competitive centralized heuristics to select a connected correlationdominating set of small size. The designed distributed algorithms can be implemented in an asynchronous communication model, and can tolerate message losses. We also design an exponential (but nonexhaustive) centralized approximation algorithm that returns a solution within O(log n) of the optimal size. Based on the approximation algorithm, we design a class of centralized heuristics that are empirically shown to return nearoptimal solutions. Simulation results over randomly generated sensor networks with both artificially and naturally generated data sets demonstrate the efficiency of the designed algorithms and the viability of our technique – even in dynamic conditions.
Three Poweraware Routing Algorithms for Sensor Networks
 Wireless Communications and Mobile Computing
, 2002
"... This paper discusses online poweraware routing in large wireless adhoc networks (especially sensor networks) for applications where the message sequence is not known. We seek to optimize the lifetime of the network. We show that online poweraware routing does not have a constant competitive ratio ..."
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Cited by 31 (2 self)
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This paper discusses online poweraware routing in large wireless adhoc networks (especially sensor networks) for applications where the message sequence is not known. We seek to optimize the lifetime of the network. We show that online poweraware routing does not have a constant competitive ratio to the offline optimal algorithm. We develop an approximation algorithm called maxmin zPmin that has a good empirical competitive ratio. To ensure scalability, we introduce a second online algorithm for poweraware routing.
Consensus in Ad Hoc WSNs With Noisy Links—Part II: Distributed Estimation and Smoothing of Random Signals
"... Abstract—Distributed algorithms are developed for optimal estimation of stationary random signals and smoothing of (even nonstationary) dynamical processes based on generally correlated observations collected by ad hoc wireless sensor networks (WSNs). Maximum a posteriori (MAP) and linear minimum me ..."
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Cited by 31 (5 self)
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Abstract—Distributed algorithms are developed for optimal estimation of stationary random signals and smoothing of (even nonstationary) dynamical processes based on generally correlated observations collected by ad hoc wireless sensor networks (WSNs). Maximum a posteriori (MAP) and linear minimum meansquare error (LMMSE) schemes, well appreciated for centralized estimation, are shown possible to reformulate for distributed operation through the iterative (alternatingdirection) method of multipliers. Sensors communicate with singlehop neighbors their individual estimates as well as multipliers measuring how far local estimates are from consensus. When iterations reach consensus, the resultant distributed (D) MAP and LMMSE estimators converge to their centralized counterparts when intersensor communication links are ideal. The DMAP estimators do not require the desired estimator to be expressible in closed form, the DLMMSE ones are provably robust to communication or quantization noise and both are particularly simple to implement when the data model is linearGaussian. For decentralized tracking applications, distributed Kalman filtering and smoothing algorithms are derived for anytime MMSE optimal consensusbased state estimation using WSNs. Analysis and corroborating numerical examples demonstrate the merits of the novel distributed estimators. Index Terms—Distributed estimation, Kalman smoother, nonlinear optimization, wireless sensor networks (WSNs).