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14
Broadcasting algorithms in radio networks with unknown topology
 In Proc. of FOCS
, 2003
"... In this paper we present new randomized and deterministic algorithms for the classical problem of broadcasting in radio networks with unknown topology. We consider directed nnode radio networks with specified eccentricity D (maximum distance from the source node to any other node). In a seminal wor ..."
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In this paper we present new randomized and deterministic algorithms for the classical problem of broadcasting in radio networks with unknown topology. We consider directed nnode radio networks with specified eccentricity D (maximum distance from the source node to any other node). In a seminal work on randomized broadcasting, BarYehuda et al. presented an algorithm that for any nnode radio network with eccentricity D completes the broadcasting in O(D log n + log 2 n) time, with high probability. This result is almost optimal, since as it has been shown by Kushilevitz and Mansour and Alon et al., every randomized algorithm requires Ω(D log(n/D)+log 2 n) expected time to complete broadcasting. Our first main result closes the gap between the lower
Opportunistic Information Dissemination in Mobile Adhoc Networks: The Profit of Global Synchrony
"... The topic of this paper is the study of Information Dissemination in Mobile Adhoc Networks by means of deterministic protocols. We characterize the connectivity resulting from the movement, from failures and from the fact that nodes may join the computation at different times with two values, α an ..."
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Cited by 2 (1 self)
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The topic of this paper is the study of Information Dissemination in Mobile Adhoc Networks by means of deterministic protocols. We characterize the connectivity resulting from the movement, from failures and from the fact that nodes may join the computation at different times with two values, α and β, so that, within α time slots, some node that has the information must be connected to some node without it for at least β time slots. The protocols studied are classified into three classes: oblivious (the transmission schedule of a node is only a function of its ID), quasioblivious (the transmission schedule may also depend on a global time), and adaptive. The main contribution of this work concerns negative results. Contrasting the lower and upper bounds derived, interesting complexity gaps among protocolclasses are observed. More precisely, in order to guarantee any progress towards solving the problem, it is shown that β must be at least n − 1 in general, but that β ∈ Ω(n 2 / log n) if an oblivious protocol is used. Since quasioblivious protocols can guarantee progress with β ∈ O(n), this represents a significant gap,
Unbounded Contention Resolution in MultipleAccess Channels ⋆
"... Abstract. A frequent problem in settings where a unique resource must be shared among users is how to resolve the contention that arises when all of them must use it, but the resource allows only for one user each time. The application of efficient solutions for this problem spans a myriad of settin ..."
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Abstract. A frequent problem in settings where a unique resource must be shared among users is how to resolve the contention that arises when all of them must use it, but the resource allows only for one user each time. The application of efficient solutions for this problem spans a myriad of settings such as radio communication networks or databases. For the case where the number of users is unknown, recent work has yielded fruitful results for local area networks and radio networks, although either a (possibly loose) upper bound on the number of users needs to be known [7], or the solution is suboptimal [2], or it is only implicit [11] or embedded [6] in other problems, with bounds proved only asymptotically. In this paper, under the assumption that collision detection or information on the number of contenders is not available, we present a novel protocol for contention resolution in radio networks, and we recreate a protocol previously used for other problems [6, 11], tailoring the constants for our needs. In contrast with previous work, both protocols are proved to be optimal up to a small constant factor and with high probability for big enough number of contenders. Additionally, the protocols are evaluated and contrasted with the previous work by extensive simulations. The evaluation shows that the complexity bounds obtained by the analysis are rather tight, and that both protocols proposed have small and predictable complexity for many system sizes (unlike previous proposals). 1
DOI: 10.1142/S1793830910000796 CONTENTION RESOLUTION IN MULTIPLEACCESS CHANNELS: kSELECTION IN RADIO NETWORKS ∗
, 2010
"... In this paper, contention resolution among k contenders on a multipleaccess channel is explored. The problem studied has been modeled as a kSelection in Radio Networks, in which every contender has to have exclusive access at least once to a shared communication channel. The randomized adaptive pr ..."
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In this paper, contention resolution among k contenders on a multipleaccess channel is explored. The problem studied has been modeled as a kSelection in Radio Networks, in which every contender has to have exclusive access at least once to a shared communication channel. The randomized adaptive protocol presented shows that, for a probability of error 2ε, all the contenders get access to the channel in time (e+1+ξ)k+O(log 2 (1/ε)), where ε ≤ 1/(n+1), ξ>0 is any constant arbitrarily close to 0, and n is the total number of potential contenders. The above time complexity is asymptotically optimal for any significant ε. The protocol works even if the number of contenders k is unknown and collisions cannot be detected.
Contents
, 2006
"... Discrete Mathematics and Theoretical Computer Science DMTCS vol. (subm.), by the authors, 1–1 A probabilistic analysis of a leader election algorithm ..."
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Discrete Mathematics and Theoretical Computer Science DMTCS vol. (subm.), by the authors, 1–1 A probabilistic analysis of a leader election algorithm
Contention Resolution in MultipleAccess Channels: kSelection in Radio Networks ⋆
"... Abstract. In this paper, contention resolution among k contenders on a multipleaccess channel is explored. The problem studied has been modeled as a kSelection in Radio Networks, in which every contender has to have exclusive access at least once to a shared communication channel. The randomized a ..."
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Abstract. In this paper, contention resolution among k contenders on a multipleaccess channel is explored. The problem studied has been modeled as a kSelection in Radio Networks, in which every contender has to have exclusive access at least once to a shared communication channel. The randomized adaptive protocol presented shows that, for a probability of error 2ε, all the contenders get access to the channel in time (e+1+ξ)k+ O(log 2 (1/ε)), where ε ≤ 1/(n + 1), ξ> 0 is any constant arbitrarily close to 0, and n is the total number of potential contenders. The above time complexity is asymptotically optimal for any significant ε. The protocol works even if the number of contenders k is unknown and collisions can not be detected. 1
kSelection in Radio Networks ∗
"... Using kSelection in Radio Networks as an example of uniqueresource dispute among k unknown contenders, the conflictresolution protocol presented in this paper shows that, for any sensible probability of error ε, all of them get access to such resource in asymptotically optimal time (e + 1 + ξ)k + ..."
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Using kSelection in Radio Networks as an example of uniqueresource dispute among k unknown contenders, the conflictresolution protocol presented in this paper shows that, for any sensible probability of error ε, all of them get access to such resource in asymptotically optimal time (e + 1 + ξ)k + O(log 2 (1/ε)), where ξ> 0 is any constant arbitrarily close to 0. This protocol works under a model where not even an upper bound on k is known and conflicts can not be detected by all the contenders. 1
Leader Election Protocol for Energy Efficient Mobile Sensor Networks (EYES)
, 2002
"... In this paper we develop and analyze a wireless wave leader election protocol (WWLE) for wireless mobile ad hoc networks, with emphasis on the resulting energy consumption. Within the operating system of the EYES m'chitecture we apply a power model to schedule tasks in order to minimize ener ..."
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In this paper we develop and analyze a wireless wave leader election protocol (WWLE) for wireless mobile ad hoc networks, with emphasis on the resulting energy consumption. Within the operating system of the EYES m'chitecture we apply a power model to schedule tasks in order to minimize energy consumption. This model is applied to evaluate the protocol for different network topologies, taking into account mobility. Performance indications m'e the number of rounds and exchanged messages and power consumption. The capabilities of a node being a leader (like available resources such as battery energy, network capabilities, etc.) m'e integrated in the algorithm. The results of simulation show that the algorithm is efficient in number of rounds and number of messages, and these result in a low energy consumption.