82 research outputs found
Message and time efficient multi-broadcast schemes
We consider message and time efficient broadcasting and multi-broadcasting in
wireless ad-hoc networks, where a subset of nodes, each with a unique rumor,
wish to broadcast their rumors to all destinations while minimizing the total
number of transmissions and total time until all rumors arrive to their
destination. Under centralized settings, we introduce a novel approximation
algorithm that provides almost optimal results with respect to the number of
transmissions and total time, separately. Later on, we show how to efficiently
implement this algorithm under distributed settings, where the nodes have only
local information about their surroundings. In addition, we show multiple
approximation techniques based on the network collision detection capabilities
and explain how to calibrate the algorithms' parameters to produce optimal
results for time and messages.Comment: In Proceedings FOMC 2013, arXiv:1310.459
Distributed Deterministic Broadcasting in Uniform-Power Ad Hoc Wireless Networks
Development of many futuristic technologies, such as MANET, VANET, iThings,
nano-devices, depend on efficient distributed communication protocols in
multi-hop ad hoc networks. A vast majority of research in this area focus on
design heuristic protocols, and analyze their performance by simulations on
networks generated randomly or obtained in practical measurements of some
(usually small-size) wireless networks. %some library. Moreover, they often
assume access to truly random sources, which is often not reasonable in case of
wireless devices. In this work we use a formal framework to study the problem
of broadcasting and its time complexity in any two dimensional Euclidean
wireless network with uniform transmission powers. For the analysis, we
consider two popular models of ad hoc networks based on the
Signal-to-Interference-and-Noise Ratio (SINR): one with opportunistic links,
and the other with randomly disturbed SINR. In the former model, we show that
one of our algorithms accomplishes broadcasting in rounds, where
is the number of nodes and is the diameter of the network. If nodes
know a priori the granularity of the network, i.e., the inverse of the
maximum transmission range over the minimum distance between any two stations,
a modification of this algorithm accomplishes broadcasting in
rounds.
Finally, we modify both algorithms to make them efficient in the latter model
with randomly disturbed SINR, with only logarithmic growth of performance.
Ours are the first provably efficient and well-scalable, under the two
models, distributed deterministic solutions for the broadcast task.Comment: arXiv admin note: substantial text overlap with arXiv:1207.673
07151 Abstracts Collection -- Geometry in Sensor Networks
From 9.4.2007 to 13.4.07, the Dagstuhl Seminar 07151 ``Geometry in Sensor
Networks\u27\u27 was held in the International Conference and Research Center
(IBFI), Schloss Dagstuhl.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first
section describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available
Data Dissemination in Unified Dynamic Wireless Networks
We give efficient algorithms for the fundamental problems of Broadcast and
Local Broadcast in dynamic wireless networks. We propose a general model of
communication which captures and includes both fading models (like SINR) and
graph-based models (such as quasi unit disc graphs, bounded-independence
graphs, and protocol model). The only requirement is that the nodes can be
embedded in a bounded growth quasi-metric, which is the weakest condition known
to ensure distributed operability. Both the nodes and the links of the network
are dynamic: nodes can come and go, while the signal strength on links can go
up or down.
The results improve some of the known bounds even in the static setting,
including an optimal algorithm for local broadcasting in the SINR model, which
is additionally uniform (independent of network size). An essential component
is a procedure for balancing contention, which has potentially wide
applicability. The results illustrate the importance of carrier sensing, a
stock feature of wireless nodes today, which we encapsulate in primitives to
better explore its uses and usefulness.Comment: 28 pages, 2 figure
Distributed local broadcasting algorithms in the physical interference model
Given a set of sensor nodes V where each node wants to broadcast a message to all its neighbors that are within a certain broadcasting range, the local broadcasting problem is to schedule all these requests in as few timeslots as possible. In this paper, assuming the more realistic physical interference model and no knowledge of the topology, we present three distributed local broadcasting algorithms where the first one is for the asynchronized model and the other two are for the synchronized model. Under the asynchronized model, nodes may join the execution of the protocol at any time and do not have access to a global clock, for which we give a distributed randomized algorithm with approximation ratio O(log n).published_or_final_versionThe 2011 International Conference on Distributed Computing in Sensor Systems and Workshops (DCOSS), Barcelona, Spain, 27-29 June 2011. In Proceedings of DCOSS, 2011, p. 1-
Achieving Dilution without Knowledge of Coordinates in the SINR Model
Considerable literature has been developed for various fundamental
distributed problems in the SINR (Signal-to-Interference-plus-Noise-Ratio)
model for radio transmission. A setting typically studied is when all nodes
transmit a signal of the same strength, and each device only has access to
knowledge about the total number of nodes in the network , the range from
which each node's label is taken , and the label of the device
itself. In addition, an assumption is made that each node also knows its
coordinates in the Euclidean plane. In this paper, we create a technique which
allows algorithm designers to remove that last assumption. The assumption about
the unavailability of the knowledge of the physical coordinates of the nodes
truly captures the `ad-hoc' nature of wireless networks.
Previous work in this area uses a flavor of a technique called dilution, in
which nodes transmit in a (predetermined) round-robin fashion, and are able to
reach all their neighbors. However, without knowing the physical coordinates,
it's not possible to know the coordinates of their containing (pivotal) grid
box and seemingly not possible to use dilution (to coordinate their
transmissions). We propose a new technique to achieve dilution without using
the knowledge of physical coordinates. This technique exploits the
understanding that the transmitting nodes lie in 2-D space, segmented by an
appropriate pivotal grid, without explicitly referring to the actual physical
coordinates of these nodes. Using this technique, it is possible for every weak
device to successfully transmit its message to all of its neighbors in
rounds, as long as the density of transmitting nodes in any
physical grid box is bounded by a known constant. This technique, we feel, is
an important generic tool for devising practical protocols when physical
coordinates of the nodes are not known.Comment: 10 page
Uniting General-Graph and Geometric-Based Radio Networks via Independence Number Parametrization
In the study of radio networks, the tasks of broadcasting (propagating a message throughout the network) and leader election (having the network agree on a node to designate ‘leader’) are two of the most fundamental global problems, and have a long history of work devoted to them. This work has two divergent strands: some works focus on exploiting the geometric properties of wireless networks based in physical space, while others consider general graphs. Algorithmic results in each of these avenues have often used quite different techniques, and produced bounds using incomparable parametrizations. In this work, we unite the study of general-graph and geometric-based radio networks, by adapting the broadcast and leader election algorithm of Czumaj and Davies (JACM ’21) to achieve a running-time parametrized by the independence number of the network (i.e., the size of the maximum independent set). This parametrization preserves the running time on general graphs, matching the best known, but also improves running times to near-optimality across a wide range of geometric-based graph classes. As part of this algorithm, we also provide the first algorithm for computing a maximal independent set in general-graph radio networks. This algorithm runs in O(log3 n) time-steps, only a log n factor away from the Ω(log2 n) lower bound
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