29,336 research outputs found
Low-Complexity Energy-Efficient Broadcasting in One-Dimensional Wireless Networks
In this paper, we investigate the transmission range assignment for N
wireless nodes located on a line (a linear wireless network) for broadcasting
data from one specific node to all the nodes in the network with minimum
energy. Our goal is to find a solution that has low complexity and yet performs
close to optimal. We propose an algorithm for finding the optimal assignment
(which results in the minimum energy consumption) with complexity O(N^2). An
approximation algorithm with complexity O(N) is also proposed. It is shown
that, for networks with uniformly distributed nodes, the linear-time
approximate solution obtained by this algorithm on average performs practically
identical to the optimal assignment. Both the optimal and the suboptimal
algorithms require the full knowledge of the network topology and are thus
centralized. We also propose a distributed algorithm of negligible complexity,
i.e., with complexity O(1), which only requires the knowledge of the adjacent
neighbors at each wireless node. Our simulations demonstrate that the
distributed solution on average performs almost as good as the optimal one for
networks with uniformly distributed nodes.Comment: 17 page
A Quantum Broadcasting Problem in Classical Low Power Signal Processing
We pose a problem called ``broadcasting Holevo-information'': given an
unknown state taken from an ensemble, the task is to generate a bipartite state
transfering as much Holevo-information to each copy as possible.
We argue that upper bounds on the average information over both copies imply
lower bounds on the quantum capacity required to send the ensemble without
information loss. This is because a channel with zero quantum capacity has a
unitary extension transfering at least as much information to its environment
as it transfers to the output.
For an ensemble being the time orbit of a pure state under a Hamiltonian
evolution, we derive such a bound on the required quantum capacity in terms of
properties of the input and output energy distribution. Moreover, we discuss
relations between the broadcasting problem and entropy power inequalities.
The broadcasting problem arises when a signal should be transmitted by a
time-invariant device such that the outgoing signal has the same timing
information as the incoming signal had. Based on previous results we argue that
this establishes a link between quantum information theory and the theory of
low power computing because the loss of timing information implies loss of free
energy.Comment: 28 pages, late
Radio frequency for particle accelerators: evolution and anatomy of a technology
This introductory lecture outlines the impressive progress of radio frequency
technology, from the first table-top equipment to the present gigantic
installations. The outcome of 83 years of evolution is subsequently submitted
to an anatomical analysis, which allows identifying the main components of a
modern RF system and their interrelations.Comment: 14 pages, contribution to the CAS - CERN Accelerator School:
Specialised Course on RF for Accelerators; 8 - 17 Jun 2010, Ebeltoft, Denmar
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
Optimisation of Mobile Communication Networks - OMCO NET
The mini conference “Optimisation of Mobile Communication Networks” focuses on advanced methods for search and optimisation applied to wireless communication networks. It is sponsored by Research & Enterprise Fund Southampton Solent University.
The conference strives to widen knowledge on advanced search methods capable of optimisation of wireless communications networks. The aim is to provide a forum for exchange of recent knowledge, new ideas and trends in this progressive and challenging area. The conference will popularise new successful approaches on resolving hard tasks such as minimisation of transmit power, cooperative and optimal routing
- …