OSA's Digital Library

Journal of Optical Communications and Networking

Journal of Optical Communications and Networking

  • Editors: K. Bergman and V. Chan
  • Vol. 2, Iss. 9 — Sep. 1, 2010
  • pp: 689–700

Thresholding-Based Optimal Detection of Wireless Optical Signals

Hassan Moradi, Hazem H. Refai, and Peter G. LoPresti  »View Author Affiliations

Journal of Optical Communications and Networking, Vol. 2, Issue 9, pp. 689-700 (2010)

View Full Text Article

Enhanced HTML    Acrobat PDF (526 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



The receiver design for a high-speed free-space (wireless) optics (FSO) signal is necessarily highly complex when channel state information (CSI) is not available. Currently, although most approaches provide high detection performance in terms of bit error, receiver design is difficult to implement. This paper proposes two practical thresholding-based detection schemes, which offer significant improvement to receiver throughput on a computational load basis when CSI is not available. The first is based on a simple maximum likelihood (ML) function where the bit error rate (BER) is the same as conventional symbol-by-symbol detection. This method, however, causes a loss of BER performance. The second uses the aid of pilot-symbol-assisted modulation (PSAM) to modify the ML function when channel coefficients are temporally correlated. While numerical analysis based on this method shows that the BER performance in a lognormally distributed fading channel is very close to detection achieved with perfect CSI, the receiver suffers from increased complexity. If random processes for fading and noise are assumed as stationary and given that the detection threshold is quickly calculated and applied during a given period, such complexity of PSAM-based and symbol-by-symbol detection methods can be reduced.

© 2010 Optical Society of America

OCIS Codes
(010.1330) Atmospheric and oceanic optics : Atmospheric turbulence
(060.2605) Fiber optics and optical communications : Free-space optical communication

ToC Category:
Research Papers

Original Manuscript: March 29, 2010
Revised Manuscript: June 15, 2010
Manuscript Accepted: July 13, 2010
Published: August 25, 2010

Hassan Moradi, Hazem H. Refai, and Peter G. LoPresti, "Thresholding-Based Optimal Detection of Wireless Optical Signals," J. Opt. Commun. Netw. 2, 689-700 (2010)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. H. Moradi, H. H. Refai, P. G. LoPresti, M. Atiquzzaman, “A PSAM-based estimator of noise and fading statistics for optimum receivers of free space optics signals,” Proc. SPIE, vol. 7587, pp. 75870O1–75870O10, Jan. 2010.
  2. N. Letzepis, I. Holland, W. Cowley, “The Gaussian free space optical MIMO channel with Q-ary pulse position modulation,” IEEE Trans. Wireless Commun., vol. 7, no. 5, pp. 1744–1753, 2008. [CrossRef]
  3. H. Moradi, M. Falahpour, H. H. Refai, P. G. LoPresti, M. Atiquzzaman, “BER analysis of optical wireless signals through lognormal fading channels with perfect CSI,” in IEEE 17th Int. Conf. on Telecommunications, Doha, Qatar, 2010, pp. 493–497.
  4. W. O. Popoola, Z. Ghassemlooy, C. G. Lee, A. C. Boucouvalas, “Scintillation effect on intensity modulated laser communication systems—a laboratory demonstration,” Opt. Laser Technol., vol. 42, no. 4, pp. 682–692, June 2010. [CrossRef]
  5. X. Zhu, J. M. Kahn, “Free-space optical communication through atmospheric turbulence channels,” IEEE Trans. Commun., vol. 50, no. 8, pp. 1293–1300, Aug. 2002. [CrossRef]
  6. S. Hitam, M. K. Abdullah, M. A. Mahdi, H. Harun, A. Sali, M. Fauzi, “Impact of increasing threshold level on higher bit rate in free space optical communications,” J. Opt. Fiber Commun. Res., vol. 6, no. 1–6, pp. 22–34, Dec. 2009. [CrossRef]
  7. M. L. B. Riediger, R. Schober, L. Lampe, “Decision-feedback detection for free-space optical communications,” in IEEE 66th Vehicular Technology Conf., 2007, pp. 1193–1197.
  8. M. L. B. Riediger, R. Schober, L. Lampe, “Fast multiple-symbol detection for free-space optical communications,” IEEE Trans. Commun., vol. 57, no. 4, pp. 1119–1128, Apr. 2009. [CrossRef]
  9. X. Zhu, J. M. Kahn, “Pilot-symbol assisted modulation for correlated turbulent free-space optical channels,” Proc. SPIE, vol. 4489, pp. 138–145, 2002. [CrossRef]
  10. I. I. Kim, E. Korevaar, “Availability of free space optics (FSO) and hybrid FSO/RF systems,” Proc. SPIE, vol. 4530, pp. 84–95, Aug. 2001. [CrossRef]
  11. A. Harris, J. J. Sluss, H. H. Refai, P. G. LoPresti, “Free-space optical wavelength diversity scheme for fog mitigation in a ground-to-unmanned aerial-vehicle communications link,” Opt. Eng., vol. 45, pp. 1–12, 2006. [CrossRef]
  12. R. M. Gagliardi, S. Karp, Optical Communications, 2nd ed.Wiley, 1995.
  13. T. A. Tsiftsis, H. G. Sandalidis, G. K. Karagiannidis, M. Uysal, “Optical wireless links with spatial diversity over strong atmospheric turbulence channels,” IEEE Trans. Wireless Commun., vol. 8, no. 2, pp. 951–957, Feb. 2009. [CrossRef]
  14. S. M. Kay, Intuitive Probability and Random Processes Using MATLAB. Springer, 2006. [CrossRef]
  15. A. Kaw, E. E. Kalu, Numerical Methods With Applications, 1st ed.2008.
  16. M. Abramowitz, I. A. Stegun, Handbook of Mathematical Functions With Formulas, Graphs, and Mathematical Tables. U.S. Department of Commerce, 1964.
  17. G. H. Golub, C. F. Van Loan, Matrix Computations, 3rd ed.Johns Hopkins U. Press, 1996.
  18. http://www.alglib.net/matrixops/symmetric/cholesky.php.
  19. A. Jurado-Navas, A. Puerta-Notario, “Generation of correlated scintillations on atmospheric optical communication,” J. Opt. Commun. Netw., vol. 1, no. 5, pp. 452–462, Oct. 2009. [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited