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Journal of Optical Communications and Networking

Journal of Optical Communications and Networking

  • Editors: K. Bergman and V. Chan
  • Vol. 1, Iss. 6 — Nov. 1, 2009
  • pp: 580–593

Fading Reduction by Aperture Averaging and Spatial Diversity in Optical Wireless Systems

Mohammad-Ali Khalighi, Noah Schwartz, Naziha Aitamer, and Salah Bourennane  »View Author Affiliations

Journal of Optical Communications and Networking, Vol. 1, Issue 6, pp. 580-593 (2009)

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Atmospheric turbulence can cause a significant performance degradation in free-space optical communication systems. It is well known that the effect of turbulence can be reduced by performing aperture averaging and/or employing spatial diversity at the receiver. In this paper, we provide a synthesis on the effectiveness of these techniques under different atmospheric turbulence conditions from a telecommunication point of view. In particular, we quantify the performance improvement in terms of average bit error rate (BER) and outage capacity, which are among important parameters in practice. The efficiency of channel coding and the feasibility of exploiting time diversity in aperture averaging receivers are discussed as well. We also compare single- and multiple-aperture systems from the point of view of fading reduction by considering uncorrelated fading on adjacent apertures for the latter case. We show that when the receiver is background noise limited, the use of multiple apertures is largely preferred to a single large aperture under strong turbulence conditions. A single aperture is likely to be preferred under moderate turbulence conditions, however. When the receiver is thermal noise limited, even under strong turbulence conditions, the use of multiple apertures is interesting only when working at a very low BER. We also provide discussions on several practical issues related to system implementation.

© 2009 Optical Society of America

OCIS Codes
(060.4510) Fiber optics and optical communications : Optical communications
(060.2605) Fiber optics and optical communications : Free-space optical communication

ToC Category:
Research Papers

Original Manuscript: June 19, 2009
Revised Manuscript: September 25, 2009
Manuscript Accepted: October 9, 2009
Published: October 30, 2009

Mohammad-Ali Khalighi, Noah Schwartz, Naziha Aitamer, and Salah Bourennane, "Fading Reduction by Aperture Averaging and Spatial Diversity in Optical Wireless Systems," J. Opt. Commun. Netw. 1, 580-593 (2009)

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