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18
Adversarial contention resolution for simple channels
 In: 17th Annual Symposium on Parallelism in Algorithms and Architectures
, 2005
"... This paper analyzes the worstcase performance of randomized backoff on simple multipleaccess channels. Most previous analysis of backoff has assumed a statistical arrival model. For batched arrivals, in which all n packets arrive at time 0, we show the following tight highprobability bounds. Rand ..."
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Cited by 32 (1 self)
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This paper analyzes the worstcase performance of randomized backoff on simple multipleaccess channels. Most previous analysis of backoff has assumed a statistical arrival model. For batched arrivals, in which all n packets arrive at time 0, we show the following tight highprobability bounds. Randomized binary exponential backoff has makespan Θ(nlgn), and more generally, for any constant r, rexponential backoff has makespan Θ(nlog lgr n). Quadratic backoff has makespan Θ((n/lg n) 3/2), and more generally, for r> 1, rpolynomial backoff has makespan Θ((n/lg n) 1+1/r). Thus, for batched inputs, both exponential and polynomial backoff are highly sensitive to backoff constants. We exhibit a monotone superpolynomial subexponential backoff algorithm, called loglogiterated backoff, that achieves makespan Θ(nlg lgn/lg lglgn). We provide a matching lower bound showing that this strategy is optimal among all monotone backoff algorithms. Of independent interest is that this lower bound was proved with a delay sequence argument. In the adversarialqueuing model, we present the following stability and instability results for exponential backoff and loglogiterated backoff. Given a (λ,T)stream, in which at most n = λT packets arrive in any interval of size T, exponential backoff is stable for arrival rates of λ = O(1/lgn) and unstable for arrival rates of λ = Ω(lglgn/lg n); loglogiterated backoff is stable for arrival rates of λ = O(1/(lg lgnlgn)) and unstable for arrival rates of λ = Ω(1/lg n). Our instability results show that bursty input is close to being worstcase for exponential backoff and variants and that even small bursts can create instabilities in the channel.
A JammingResistant MAC Protocol for SingleHop Wireless Networks
, 2008
"... In this paper we consider the problem of designing a medium access control (MAC) protocol for singlehop wireless networks that is provably robust against adaptive adversarial jamming. The wireless network consists of a set of honest and reliable nodes that are within the transmission range of each ..."
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Cited by 28 (9 self)
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In this paper we consider the problem of designing a medium access control (MAC) protocol for singlehop wireless networks that is provably robust against adaptive adversarial jamming. The wireless network consists of a set of honest and reliable nodes that are within the transmission range of each other. In addition to these nodes there is an adversary. The adversary may know the protocol and its entire history and use this knowledge to jam the wireless channel at will at any time. It is allowed to jam a (1 − ɛ)fraction of the time steps, for an arbitrary constant ɛ> 0, but it has to make a jamming decision before it knows the actions of the nodes at the current step. The nodes cannot distinguish between the adversarial jamming or a collision of two or more messages that are sent at the same time. We demonstrate, for the first time, that there is a localcontrol MAC protocol requiring only very limited knowledge about the adversary and the network that achieves a constant throughput for the nonjammed time steps under any adversarial strategy above. We also show that our protocol is very energy efficient and that it can be extended to obtain a robust and efficient protocol for leader election and the fair use of the wireless channel.
Adversarial queuing on the multipleaccess channel
 In Proc. of PODC ’06
, 2006
"... We consider broadcasting on the multipleaccess channel when packets are injected continuously. Multipleaccess channel is a synchronous system with the properties that a single transmission at a round delivers the message to all nodes, while multiple simultaneous transmissions result in a conflict ..."
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Cited by 16 (8 self)
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We consider broadcasting on the multipleaccess channel when packets are injected continuously. Multipleaccess channel is a synchronous system with the properties that a single transmission at a round delivers the message to all nodes, while multiple simultaneous transmissions result in a conflict which prevents delivering messages to any among the recipients. The traditional approach to dynamic broadcasting has been concerned with stability of protocols under suitable stochastic assumptions about injection rates. We study deterministic protocols competing against adversaries restricted by injection rate and burstiness of traffic. Stability means that the number of packets in queues is bounded by a constant in any execution, for a given number of stations, protocol, and adversary. Strong stability denotes the
Randomized communication in radio networks
 HANDBOOK OF RANDOMIZED COMPUTING
, 2001
"... A communication network is called a radio network if its nodes exchange messages in the following restricted way. First, a send operation performed by a node delivers copies of the same message to all directly reachable nodes. Secondly, a node can successfully receive an incoming message only if exa ..."
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Cited by 14 (0 self)
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A communication network is called a radio network if its nodes exchange messages in the following restricted way. First, a send operation performed by a node delivers copies of the same message to all directly reachable nodes. Secondly, a node can successfully receive an incoming message only if exactly one of its neighbors sent a message in that step. It is this semantics of how ports at nodes send and receive messages that defines the networks rather than the fact that only radio waves are used as a medium of communication; but if that is the case then just a single frequency is used. We discuss algorithmic aspects of exchanging information in such networks, concentrating on distributed randomized protocols. Specific problems and solutions depend a lot on the topology of the underlying reachability graph and how much the nodes know about it. In singlehop networks each pair of nodes can communicate directly. This kind of networks is also known as the multiple access channel. Popular
A Bound on the Capacity of Backoff and AcknowledgementBased Protocols
, 2000
"... We study contentionresolution protocols for multipleaccess channels. We show that every backo protocol is transient if the arrival rate, , is at least 0.42 and that the capacity of every backo protocol is at most 0.42. Thus, we show that backo protocols have (provably) smaller capacity than fulls ..."
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Cited by 12 (0 self)
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We study contentionresolution protocols for multipleaccess channels. We show that every backo protocol is transient if the arrival rate, , is at least 0.42 and that the capacity of every backo protocol is at most 0.42. Thus, we show that backo protocols have (provably) smaller capacity than fullsensing protocols. Finally, we show that the corresponding results, with the larger arrival bound of 0.531, also hold for every acknowledgementbased protocol.
A JammingResistant MAC Protocol for MultiHop Wireless Networks
, 2010
"... This paper presents a simple local medium access control protocol, called Jade, for multihop wireless networks with a single channel that is provably robust against adaptive adversarial jamming. The wireless network is modeled as a unit disk graph on a set of nodes distributed arbitrarily in the p ..."
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Cited by 12 (7 self)
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This paper presents a simple local medium access control protocol, called Jade, for multihop wireless networks with a single channel that is provably robust against adaptive adversarial jamming. The wireless network is modeled as a unit disk graph on a set of nodes distributed arbitrarily in the plane. In addition to these nodes, there are adversarial jammers that know the protocol and its entire history and that are allowed to jam the wireless channel at any node for an arbitrary (1 − ɛ)fraction of the time steps, where 0 <ɛ<1 is an arbitrary constant. We assume that the nodes cannot distinguish between jammed transmissions and collisions of regular messages. Nevertheless, we show that Jade achieves an asymptotically optimal throughput if there is a sufficiently dense distribution of nodes.
The DoAll Problem in Broadcast Networks
, 2001
"... The problem of performing t tasks in a distributed system on p failureprone processors is one of the fundamental problems in distributed computing. If the tasks are similar and independent and the processors communicate by sending messages then the problem is called DoAll . In our work the communi ..."
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Cited by 6 (4 self)
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The problem of performing t tasks in a distributed system on p failureprone processors is one of the fundamental problems in distributed computing. If the tasks are similar and independent and the processors communicate by sending messages then the problem is called DoAll . In our work the communication is over a multipleaccess channel, and the attached stations may fail by crashing. The measure of performance is work, defined as the number of the available processor steps. Algorithms are required to be reliable in that they perform all the tasks as long as at least one station remains operational. We show that each reliable algorithm always needs to perform at least the minimum amount t + p p t) of work. We develop an optimal deterministic algorithm for the channel with collision detection performing only the minimum work (t + p p t). Another algorithm is given for the channel without collision detection, it performs work O(t+p p t+p minff; tg), where f < p is the number of failures. It is proved to be optimal if the number of faults is the only restriction on the adversary. Finally we consider the question if randomization helps for the channel without collision detection against weaker adversaries. We develop a randomized algorithm which needs to perform only the expected minimum work if the adversary may fail a constant fraction of stations, but it has to select the failureprone stations prior to the start of an algorithm.
Adversarial Multiple Access Channel with Individual Injection Rates
"... Abstract. We study deterministic distributed broadcasting on a synchronous multipleaccess channel. Packets are injected into stations by a windowtype adversary that is constrained by an individual injection rate of each station and a window w. We investigate what queue sizes and packet latency can ..."
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Cited by 4 (2 self)
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Abstract. We study deterministic distributed broadcasting on a synchronous multipleaccess channel. Packets are injected into stations by a windowtype adversary that is constrained by an individual injection rate of each station and a window w. We investigate what queue sizes and packet latency can be achieved with the maximum throughput of one packet per round. A protocol knows the number n of all the stations but does not know the window nor the individual rates of stations. We study the power of full sensing and acknowledgment based protocols as compared to general adaptive ones. We show that individual injection rates make it possible to achieve bounded packet latency by full sensing protocols, what is in contrast with the model of global injection rates for which stability and finite waiting times are not achievable together by general protocols. We show that packet latency is Ω ` ´ log n w when w ≤ n log w and it is Ω(w) when w> n. We give a full sensing protocol for channels with collision detection and an adaptive one for channels without collision detection that achieve O(min(n + w, w log n)) packet latency. We develop a full sensing protocol for a channel without collision detection that achieves O(n + w) queues and O(nw) packet latency. 1