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366
Comparison of Broadcasting Techniques for Mobile Ad Hoc Networks
 MOBIHOC'02
, 2002
"... Network wide broadcasting in Mobile Ad Hoc Networks provides important control and route establishment functionality for a number of unicast and multicast protocols. Considering its wide use as a building block for other network layer protocols, the MANET community needs to standardize a single meth ..."
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Cited by 519 (4 self)
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Network wide broadcasting in Mobile Ad Hoc Networks provides important control and route establishment functionality for a number of unicast and multicast protocols. Considering its wide use as a building block for other network layer protocols, the MANET community needs to standardize a single methodology that efficiently delivers a packet from one node to all other network nodes. Despite a considerable number of proposed broadcasting schemes, no comprehensive comparative analysis has been previously done. This paper provides such analysis by classifying existing broadcasting schemes into categories and simulating a subset of each category, thus supplying a condensed but comprehensive side by side comparison. The simulations are designed to pinpoint, in each category, specific failures to network conditions that are relevant to MANETs, e.g., bandwidth congestion and dynamic topologies. In addition, protocol extensions using adaptive responses to network conditions are proposed, implemented and analyzed for one broadcasting scheme that performs well in the comparative study.
CEDAR: a CoreExtraction Distributed Ad hoc Routing Algorithm
 IEEE Journal on Selected Areas in Communications
, 1999
"... Absiract—CEDARis an algorithm for QoS routing in ad hoc network environments. It has three key components: (a) the establishment and maintenance of a setforganizing routing infrastructure catted the core for performing route computations, (b) the propagation of the linkstate of stable highbandw ..."
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Cited by 397 (10 self)
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Absiract—CEDARis an algorithm for QoS routing in ad hoc network environments. It has three key components: (a) the establishment and maintenance of a setforganizing routing infrastructure catted the core for performing route computations, (b) the propagation of the linkstate of stable highbandwidth links in the core through increase/decrease waves, and (c)a QoS ra,ute computation algorithm that is exeeuted at the core nodes using onty locally available state. Our preliminary performance evaluation shows that CEDAR is a robust and adaptive QoS routing algorithm that reacts effectively to the dynamics of the network white stitl approximating linkstate performance for stable networks. Keywords—Ad hoc routing, QoS routing I.
On Calculating Connected Dominating Set for Efficient Routing in Ad Hoc Wireless Networks
, 1999
"... Efficient routing among a set of mobile hosts (also called nodes) is one of the most important functions in adhoc wireless networks. Routing based on a connected dominating set is a frequently used approach, where the searching space for a route is reduced to nodes in the set. A set is dominating i ..."
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Cited by 377 (39 self)
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Efficient routing among a set of mobile hosts (also called nodes) is one of the most important functions in adhoc wireless networks. Routing based on a connected dominating set is a frequently used approach, where the searching space for a route is reduced to 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 propose a simple and efficient distributed algorithm for calculating connected dominating set in adhoc wireless networks, where connections of nodes are determined by their geographical distances. Our simulation results show that the proposed approach outperforms a classical algorithm. Our approach can be potentially used in designing efficient routing algorithms based on a connected dominating set.
Geometric AdHoc Routing: Of Theory and Practice
, 2003
"... All too often a seemingly insurmountable divide between theory and practice can be witnessed. In this paper we try to contribute to narrowing this gap in the field of adhoc routing. In particular we consider two aspects: We propose a new geometric routing algorithm which is outstandingly efficient ..."
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Cited by 317 (13 self)
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All too often a seemingly insurmountable divide between theory and practice can be witnessed. In this paper we try to contribute to narrowing this gap in the field of adhoc routing. In particular we consider two aspects: We propose a new geometric routing algorithm which is outstandingly efficient on practical averagecase networks, however is also in theory asymptotically worstcase optimal. On the other hand we are able to drop the formerly necessary assumption that the distance between network nodes may not fall below a constant value, an assumption that cannot be maintained for practical networks. Abandoning this assumption we identify from a theoretical point of view two fundamentamentally different classes of cost metrics for routing in adhoc networks.
Routing in AdHoc Networks Using Minimum Connected Dominating Sets
, 1997
"... this paper, we impose a virtual backbone structure on the adhoc network, in order to support unicast, multicast, and faulttolerant routing within the adhoc network. This virtual backbone differs from the wired backbone of cellular networks in two key ways: (a) it may change as nodes move, and (b) ..."
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Cited by 297 (3 self)
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this paper, we impose a virtual backbone structure on the adhoc network, in order to support unicast, multicast, and faulttolerant routing within the adhoc network. This virtual backbone differs from the wired backbone of cellular networks in two key ways: (a) it may change as nodes move, and (b) it is not used primarily for routing packets or flows, but only for computing and updating routes. The primary routes for packets and flows are still computed by a shortestpaths computation; the virtual backbone can, if necessary, provide backup routes to handle interim failures. Because of the dynamic nature of the virtual backbone, our approach splits the routing problem into two levels: (a) find and update the virtual backbone, and (b) then find and update routes. The key contribution of this paper is to describe several alternatives for the first part of finding and updating the virtual backbone. In this paper, to keep the virtual backbone as small as possible, we use an approximation to the minimum connected dominating set (MCDS) of the adhoc network topology as the virtual backbone. The hosts in the MCDS maintain local copies of the global topology of the network, along with shortest paths between all pairs of nodes. We note that the concept of a virtual backbone is not new. Ephremides et al.
Approximation Algorithms for Directed Steiner Problems
 Journal of Algorithms
, 1998
"... We give the first nontrivial approximation algorithms for the Steiner tree problem and the generalized Steiner network problem on general directed graphs. These problems have several applications in network design and multicast routing. For both problems, the best ratios known before our work we ..."
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Cited by 178 (8 self)
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We give the first nontrivial approximation algorithms for the Steiner tree problem and the generalized Steiner network problem on general directed graphs. These problems have several applications in network design and multicast routing. For both problems, the best ratios known before our work were the trivial O(k)approximations. For the directed Steiner tree problem, we design a family of algorithms that achieves an approximation ratio of i(i \Gamma 1)k 1=i in time O(n i k 2i ) for any fixed i ? 1, where k is the number of terminals. Thus, an O(k ffl ) approximation ratio can be achieved in polynomial time for any fixed ffl ? 0. Setting i = log k, we obtain an O(log 2 k) approximation ratio in quasipolynomial time. For the directed generalized Steiner network problem, we give an algorithm that achieves an approximation ratio of O(k 2=3 log 1=3 k), where k is the number of pairs of vertices that are to be connected. Related problems including the group Steiner...
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 ..."
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Cited by 168 (7 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.
A polylogarithmic approximation algorithm for the group Steiner tree problem
 Journal of Algorithms
, 2000
"... The group Steiner tree problem is a generalization of the Steiner tree problem where we ae given several subsets (groups) of vertices in a weighted graph, and the goal is to find a minimumweight connected subgraph containing at least one vertex from each group. The problem was introduced by Reich a ..."
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Cited by 149 (9 self)
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The group Steiner tree problem is a generalization of the Steiner tree problem where we ae given several subsets (groups) of vertices in a weighted graph, and the goal is to find a minimumweight connected subgraph containing at least one vertex from each group. The problem was introduced by Reich and Widmayer and finds applications in VLSI design. The group Steiner tree problem generalizes the set covering problem, and is therefore at least as had. We give a randomized O(log 3 n log k)approximation algorithm for the group Steiner tree problem on an nnode graph, where k is the number of groups. The best previous ink)v/ (Bateman, Helvig, performance guarantee was (1 +  Robins and Zelikovsky).
Minimumenergy broadcast routing in static ad hoc wireless networks
, 2001
"... Abstract  Energy conservation is a critical issue in ad hoc wireless networks for node and network life, as the nodes are powered by batteries only. One major approach for energy conservation is to route a communication session along the routes which requires the lowest total energy consumption. Th ..."
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Cited by 138 (9 self)
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Abstract  Energy conservation is a critical issue in ad hoc wireless networks for node and network life, as the nodes are powered by batteries only. One major approach for energy conservation is to route a communication session along the routes which requires the lowest total energy consumption. This optimization problem is referred to as minimumenergy routing. While minimumenergy unicast routing can be solved in polynomial time by shortestpath algorithms, it remains open whether minimumenergy broadcast routing can be solved in polynomial time, despite of the NPhardness of its general graph version. Recently three greedy heuristics were proposed in [8]: MST (minimum spanning tree), SPT (shortestpath tree), and BIP (broadcasting incremental power). They have been evaluated through simulations in [8], but little is known about their analytical performance. The main contribution of this paper is the quantitative characterization of their performances in terms of approximation ratios. By exploring geometric structures of Euclidean MSTs, we havebeen able to prove that the approximation ratio of MST is between 6 and 12, and the approximation ratio of BIP is between 13 and 12. On the 3 other hand, the approximation ratio of SPT is shown to be at least n,wherenis the number of receiving nodes. To 2 our best knowledge, these are the rst analytical results for minimumenergy broadcasting. I.
ConstantTime Distributed Dominating Set Approximation
 In Proc. of the 22 nd ACM Symposium on the Principles of Distributed Computing (PODC
, 2003
"... Finding a small dominating set is one of the most fundamental problems of traditional graph theory. In this paper, we present a new fully distributed approximation algorithm based on LP relaxation techniques. For an arbitrary parameter k and maximum degree #, our algorithm computes a dominating set ..."
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Cited by 134 (22 self)
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Finding a small dominating set is one of the most fundamental problems of traditional graph theory. In this paper, we present a new fully distributed approximation algorithm based on LP relaxation techniques. For an arbitrary parameter k and maximum degree #, our algorithm computes a dominating set of expected size O k# log #DSOPT rounds where each node has to send O k messages of size O(log #). This is the first algorithm which achieves a nontrivial approximation ratio in a constant number of rounds.