Researchers at Pennsylvania State University target
2010 JAN 6 - (VerticalNews.com) -- "Free Space
Optical (FSO) communications is a practical solution for
creating a three dimensional global broadband communications
grid, offering bandwidths far beyond possible in Radio
Frequency (RF) range. However, attributes of atmospheric
turbulence (scintillation) and obscurants such as clouds
impose perennial limitations on availability and reliability
of optical links," scientists writing in the IEEE Journal
on Selected Areas in Communications report.
"To design and evaluate optimum transmission
techniques that operate under realistic atmospheric
conditions, a good understanding of the channel behavior is
necessary. In most prior works, Monte-Carlo Ray Tracing (MCRT)
algorithm has been used to analyze the channel behavior. This
task is quite numerically intensive. The focus of this paper
is on investigating the possibility of simplifying this task
by a direct extraction of state transition matrices associated
with standard Markov modeling from the MCRT computer
simulations programs. We show that by tracing a photon's
trajectory in space via a Markov chain model, the angular
distribution can be calculated by simple matrix
multiplications. We also demonstrate that the new approach
produces results that are close to those obtained by MCRT and
other known methods," wrote Z. Hajjarian and colleagues,
Pennsylvania State University.
The researchers concluded: "Furthermore,
considering the fact that angular, spatial, and temporal
distributions of energy are inter-related, mixing time of
Monte-Carlo Markov Chain (MCMC) for different types of
aerosols is calculated based on eigen-analysis of the state
transition matrix and possibility of communications in
scattering media is investigated."
Hajjarian and colleagues published their study
in IEEE Journal on Selected Areas in Communications
(Analysis of Wireless Optical Communications Feasibility in
Presence of Clouds Using Markov Chains. IEEE Journal on
Selected Areas in Communications,
Additional information can be obtained by
contacting Z. Hajjarian, Pennsylvania State University, Dept.
of Electrical Engineering, University Park, PA 16802, USA.
The publisher of the IEEE Journal on
Selected Areas in Communications can be contacted at:
IEEE-Institute Electrical Electronics Engineers Inc., 445 Hoes
Lane, Piscataway, NJ 08855, USA.
Keywords: City:University Park, State:PA,
Country:United States, Bandwidth, Broadband, Communications
Research, Computers, Electronics, Photons, Radio Frequency
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Electronics editors from staff and other reports. Copyright
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