Results 1  10
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22
Wireless scheduling with power control
 In Proc. 17th European Symposium on Algorithms (ESA
, 2009
"... We consider the scheduling of arbitrary wireless links in the physical model of interference to minimize the time for satisfying all requests. We study here the combined problem of scheduling and power control, where we seek both an assignment of power settings and a partition of the links so that e ..."
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Cited by 43 (6 self)
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We consider the scheduling of arbitrary wireless links in the physical model of interference to minimize the time for satisfying all requests. We study here the combined problem of scheduling and power control, where we seek both an assignment of power settings and a partition of the links so that each set satisfies the signaltointerferenceplusnoise (SINR) constraints. We give an algorithm that attains an approximation ratio of O(log n · log log Λ), where Λ is the ratio between the longest and the shortest linklength. Under the natural assumption that lengths are represented in binary, this gives the first polylog(n)approximation. The algorithm has the desirable property of using an oblivious power assignment, where the power assigned to a sender depends only on the length of the link. We show this dependence on Λ to be unavoidable, giving a construction for which any oblivious power assignment results in a Ω(log log Λ)approximation. We also give a simple online algorithm that yields a O(log Λ)approximation, by a reduction to the coloring of unitdisc graphs. In addition, we obtain improved approximation for a bidirectional variant of the scheduling problem, give partial answers to questions about the utility of graphs for modeling physical interference, and generalize the setting from the standard 2dimensional Euclidean plane to doubling metrics. 1
Wireless Communication is in APX
 In Proc. 36th International Colloquium on Automata, Languages and Programming (ICALP
, 2009
"... Abstract. In this paper we address a common question in wireless communication: How long does it take to satisfy an arbitrary set of wireless communication requests? This problem is known as the wireless scheduling problem. Our main result proves that wireless scheduling is in APX. In addition we pr ..."
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Cited by 31 (5 self)
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Abstract. In this paper we address a common question in wireless communication: How long does it take to satisfy an arbitrary set of wireless communication requests? This problem is known as the wireless scheduling problem. Our main result proves that wireless scheduling is in APX. In addition we present a robustness result, showing that constant parameter and model changes will modify the result only by a constant. 1
The abstract MAC layer
, 2009
"... Abstract. A diversity of possible communication assumptions complicates the study of algorithms and lower bounds for radio networks. We address this problem by defining an Abstract MAC Layer. This service provides reliable local broadcast communication, with timing guarantees stated in terms of a ..."
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Cited by 21 (14 self)
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Abstract. A diversity of possible communication assumptions complicates the study of algorithms and lower bounds for radio networks. We address this problem by defining an Abstract MAC Layer. This service provides reliable local broadcast communication, with timing guarantees stated in terms of a collection of abstract delay functions applied to the relevant contention. Algorithm designers can analyze their algorithms in terms of these functions, independently of specific channel behavior. Concrete implementations of the Abstract MAC Layer over basic radio network models generate concrete definitions for these delay functions, automatically adapting bounds proven for the abstract service to bounds for the specific radio network under consideration. To illustrate this approach, we use the Abstract MAC Layer to study the new problem of MultiMessage Broadcast, a generalization of standard singlemessage broadcast, in which any number of messages arrive at any processes at any times. We present and analyze two algorithms for MultiMessage Broadcast in static networks: a simple greedy algorithm and one that uses regional leaders. We then indicate how these results can be extended to mobile networks. 1
Broadcasting in Unreliable Radio Networks
"... Practitioners agree that unreliable links, which sometimes deliver messages and sometime do not, are an important characteristic of wireless networks. In contrast, most theoretical models of radio networks fix a static set of links and assume that these links work reliably throughout an execution. T ..."
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Cited by 12 (6 self)
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Practitioners agree that unreliable links, which sometimes deliver messages and sometime do not, are an important characteristic of wireless networks. In contrast, most theoretical models of radio networks fix a static set of links and assume that these links work reliably throughout an execution. This gap between theory and practice motivates us to investigate how unreliable links affect theoretical bounds on broadcast in radio networks. To that end we consider a model that includes two types of links: reliable links, which always deliver messages, and unreliable links, which sometimes fail to deliver messages. We assume that the reliable links induce a connected graph, and that unreliable links are controlled by a worstcase adversary. In the new model we show an Ω(
MinimumLatency Aggregation Scheduling in Wireless Sensor Networks under Physical Interference Model
"... is a problem of fundamental importance in wireless sensor networks. There however has been very little effort spent on designing algorithms to achieve sufficiently fast data aggregation under the physical interference model which is a more realistic model than traditional protocol interference model ..."
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Cited by 11 (4 self)
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is a problem of fundamental importance in wireless sensor networks. There however has been very little effort spent on designing algorithms to achieve sufficiently fast data aggregation under the physical interference model which is a more realistic model than traditional protocol interference model. In particular, a distributed solution to the problem under the physical interference model is challenging because of the need for globalscale information to compute the cumulative interference at any individual node. In this paper, we propose a distributed algorithm that solves the MLAS problem under the physical interference model in networks of arbitrary topology in O(K) time slots, where K is the logarithm of the ratio between the lengths of the longest and shortest links in the network. We also give a centralized algorithm to serve as a benchmark for comparison purposes, which aggregates data from all sources in O(log 3 (n)) time slots (where n is the total number of nodes). This is the current best algorithm for the problem in the literature. The distributed algorithm partitions the network into cells according to the value K, thus obviating the need for global information. The centralized algorithm strategically combines our aggregation tree construction algorithm with the nonlinear power assignment strategy in [13]. We prove the correctness and efficiency of our algorithms, and conduct empirical studies under realistic settings to validate our analytical results. I.
The Power of NonUniform Wireless Power
, 2012
"... We study a fundamental measure for wireless interference in the SINR model when power control is available. This measure characterizes the effectiveness of using oblivious power — when the power used by a transmitter only depends on the distance to the receiver — as a mechanism for improving wireles ..."
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Cited by 8 (2 self)
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We study a fundamental measure for wireless interference in the SINR model when power control is available. This measure characterizes the effectiveness of using oblivious power — when the power used by a transmitter only depends on the distance to the receiver — as a mechanism for improving wireless capacity. We prove optimal bounds for this measure, implying a number of algorithmic applications. An algorithm is provided that achieves — due to existing lower bounds — capacity that is asymptotically best possible using oblivious power assignments. Improved approximation algorithms are provided for a number of problems for oblivious power and for power control, including distributed scheduling, secondary spectrum auctions, wireless connectivity, and dynamic packet scheduling.
An O (logn) distributed approximation algorithm for local broadcasting in unstructured wireless networks
"... Abstract—The unstructured multihop radio network model, with asynchronous wakeup, no collision detection and little knowledge on the network topology, is proposed for capturing the particularly harsh characteristics of initially deployed wireless ad hoc and sensor networks. In this paper, assuming ..."
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Cited by 6 (2 self)
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Abstract—The unstructured multihop radio network model, with asynchronous wakeup, no collision detection and little knowledge on the network topology, is proposed for capturing the particularly harsh characteristics of initially deployed wireless ad hoc and sensor networks. In this paper, assuming such a practical model, we study a fundamental problem of both theoretical and practical interests—the local broadcasting problem. Given a set of nodes V where each node wants to broadcast a message to all its neighbors that are within a certain local broadcasting range R, the problem is to schedule all these requests in the fewest timeslots. By adopting the physical interference model and without any knowledge on neighborhood, we give a new randomized distributed approximation algorithm for the local broadcasting problem with approximation ratio O(log n) where n is the number of nodes. This distributed approximation algorithm improves the stateoftheart result in [22] by a logarithmic factor. I.
Efficient distributed multiplemessage broadcasting in unstructured wireless networks
 In INFOCOM
, 2013
"... AbstractMultiplemessage broadcast is a generalization of the traditional broadcast problem. It is to disseminate k distinct (1 ≤ k ≤ n) messages stored at k arbitrary nodes to the entire network with the fewest timeslots. In this paper, we study this basic communication primitive in unstructured ..."
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Cited by 4 (0 self)
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AbstractMultiplemessage broadcast is a generalization of the traditional broadcast problem. It is to disseminate k distinct (1 ≤ k ≤ n) messages stored at k arbitrary nodes to the entire network with the fewest timeslots. In this paper, we study this basic communication primitive in unstructured wireless networks under the physical interference model (also known as the SINR model). The unstructured wireless network assumes unknown network topology, no collision detection and asynchronous communications. Our proposed randomized distributed algorithm can accomplish multiplemessage broadcast in O((D + k) log n + log 2 n) timeslots with high probability, where D is the network diameter and n is the number of nodes in the network. To our best knowledge, this work is the first one to consider distributively implementing multiplemessage broadcasting in unstructured wireless networks under a global interference model, which may shed some light on how to efficiently solve in general a "global" problem in a "local" fashion with "global" interference constraints in asynchronous wireless ad hoc networks. Apart from the algorithm, we also show an Ω(D+k+log n) lower bound for randomized distributed multiple message broadcast algorithms under the assumed network model.
Distributed deterministic broadcasting in uniformpower ad hoc wireless networks
, 2013
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Radio Network Distributed Algorithms in the Unknown Neighborhood Model ⋆
"... Abstract. The paper deals with radio network distributed algorithms where initially no information about node degrees is available. We show that the lack of such an information affects the time complexity of existing fundamental algorithms by only a polylogarithmic factor. More precisely, given an n ..."
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Cited by 2 (0 self)
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Abstract. The paper deals with radio network distributed algorithms where initially no information about node degrees is available. We show that the lack of such an information affects the time complexity of existing fundamental algorithms by only a polylogarithmic factor. More precisely, given an nnode graph modeling a multihop radio network, we provide a O(log 2 n) time distributed algorithm that computes w.h.p., a constant approximation value of the degree of each node. We also provide a O( ∆ log n+log 2 n) time distributed algorithm that computes w.h.p., a constant approximation value of the local maximum degree of each node, where the global maximum degree ∆ of the graph is not known. Using our algorithm as a plugandplay procedure, we show that the local maximum degree can be used instead of ∆ to break the symmetry efficiently. We illustrate this claim by revisiting some fundamental algorithms that use ∆ as a key parameter. First, we investigate the generic problem of simulating any pointtopoint interferencefree message passing algorithm in the radio network model. Then, we study the fundamental coloring problem in unit disk graphs. The obtained results show that the local maximum degree allows nodes to selforganize in a local manner and to avoid the radio interferences from being a communication bottleneck. 1