DocumentCode :
2725037
Title :
Channel measurement and estimation for free space optical communications
Author :
Khatoon, Afsana ; Cowle, William G. ; Letzepis, Nick
Author_Institution :
Inst. for Telecommun. Res., Univ. of South Australia, Adelaide, SA, Australia
fYear :
2011
fDate :
Jan. 31 2011-Feb. 3 2011
Firstpage :
112
Lastpage :
117
Abstract :
Free space optical (FSO) communication links experience different fading for longer terrestrial links, which may result in lognormal, Gamma-Gamma or exponentially distributed signals under weak, modarate and strong turbulence. Channel estimation is also corrupted by background and electrical noise. In this paper, we measure the FSO fading distribution from experimental data collected from a 1550nm, 12 km long terrestrial link. Background and electrical noise statistics are found from collected noise data. We also consider the estimation of unknown parameters from FSO channel samples considering the background and electrical noise which are the sum of fading plus Gaussian noise. We determine the root mean square estimation errors (RMSE) using various methods including the Method of Moments (MOM) and iterative Maximum Likelihood (ML) estimations. We evaluate the Cramer-Rao Bounds (CRB) for these problems. We compare our estimation technique performance with existing methods of estimation which ignore Gaussian noise. The new estimation technique which takes noise into account shows significant performance improvement in the low signal to noise ratio (SNR) region. We also compare the estimation performance under varying number of channel samples. We use a single dimension approach where only one parameter is estimated at once.
Keywords :
Gaussian noise; channel estimation; maximum likelihood estimation; mean square error methods; method of moments; optical communication; space communication links; Cramer-Rao bounds; Gamma-Gamma signal; background statistics; channel estimation; channel measurement; electrical noise statistics; exponentially distributed signal; fading plus Gaussian noise; free space optical communication links; free space optical fading distribution; iterative maximum likelihood estimation; lognormal signal; method of moments; parameter estimation; root mean square estimation errors; terrestrial link; Adaptive optics; Estimation; Fading; Gaussian noise; Moment methods; Optical noise;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Communications Theory Workshop (AusCTW), 2011 Australian
Conference_Location :
Melbourne, VIC
Print_ISBN :
978-1-4244-9714-0
Type :
conf
DOI :
10.1109/AUSCTW.2011.5728747
Filename :
5728747
Link To Document :
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