TY - JOUR
T1 - Analysis of wireless optical communications feasibility in presence of clouds using Markov chains
AU - Hajjarian, Z.
AU - Kavehrad, M.
AU - Fadlullah, J.
N1 - Funding Information:
ACKNOWLEDGMENTS A DARPA Grant sponsored by the U.S. Air Force Research Laboratory/Wright-Patterson AFB Contract-FA8650-08-C-7850 and The Pennsylvania State University CICTR has supported this research. The authors would like to sincerely thank Dr. Graham J Martin of Teledyne Technologies Inc for many interesting discussions, Dr Larry Stotts, Deputy Director, Strategic Technology Office at DARPA and Mr. Brian Stadler of AFRL/RYJM for motivating the investigation. The paper is approved for Public Release, Distribution Unlimited.
PY - 2009/12
Y1 - 2009/12
N2 - 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. 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. 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.
AB - 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. 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. 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.
UR - http://www.scopus.com/inward/record.url?scp=77949843913&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77949843913&partnerID=8YFLogxK
U2 - 10.1109/JSAC.2009.091202
DO - 10.1109/JSAC.2009.091202
M3 - Article
AN - SCOPUS:77949843913
SN - 0733-8716
VL - 27
SP - 1526
EP - 1534
JO - IEEE Journal on Selected Areas in Communications
JF - IEEE Journal on Selected Areas in Communications
IS - 9
M1 - 5342312
ER -