4,750 research outputs found
Large deviations for the capacity in dynamic spatial relay networks
We derive a large deviation principle for the space-time evolution of users
in a relay network that are unable to connect due to capacity constraints. The
users are distributed according to a Poisson point process with increasing
intensity in a bounded domain, whereas the relays are positioned
deterministically with given limiting density. The preceding work on capacity
for relay networks by the authors describes the highly simplified setting where
users can only enter but not leave the system. In the present manuscript we
study the more realistic situation where users leave the system after a random
transmission time. For this we extend the point process techniques developed in
the preceding work thereby showing that they are not limited to settings with
strong monotonicity properties.Comment: 24 pages, 1 figur
Stronger wireless signals appear more Poisson
Keeler, Ross and Xia (2016) recently derived approximation and convergence
results, which imply that the point process formed from the signal strengths
received by an observer in a wireless network under a general statistical
propagation model can be modelled by an inhomogeneous Poisson point process on
the positive real line. The basic requirement for the results to apply is that
there must be a large number of transmitters with different locations and
random propagation effects.The aim of this note is to apply some of the main
results of Keeler, Ross and Xia (2016) in a less general but more easily
applicable form to illustrate how the results can be applied in practice. New
results are derived that show that it is the strongest signals, after being
weakened by random propagation effects, that behave like a Poisson process,
which supports recent experimental work.Comment: 7 pages with 1.5 line spacin
A Unifying Model for External Noise Sources and ISI in Diffusive Molecular Communication
This paper considers the impact of external noise sources, including
interfering transmitters, on a diffusive molecular communication system, where
the impact is measured as the number of noise molecules expected to be observed
at a passive receiver. A unifying model for noise, multiuser interference, and
intersymbol interference is presented, where, under certain circumstances,
interference can be approximated as a noise source that is emitting
continuously. The model includes the presence of advection and molecule
degradation. The time-varying and asymptotic impact is derived for a series of
special cases, some of which facilitate closed-form solutions. Simulation
results show the accuracy of the expressions derived for the impact of a
continuously-emitting noise source, and show how approximating intersymbol
interference as a noise source can simplify the calculation of the expected bit
error probability of a weighted sum detector.Comment: 14 pages, 7 figures, 4 tables, 1 appendix. To appear in IEEE Journal
on Selected Areas in Communications (JSAC). Submitted October 21, 2013,
revised April 21, 2014, accepted June 3, 201
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