## Estimation of channel parameters and background irradiance for free-space optical link |

Applied Optics, Vol. 52, Issue 14, pp. 3260-3268 (2013)

http://dx.doi.org/10.1364/AO.52.003260

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### Abstract

Free-space optical communication can experience severe fading due to optical scintillation in long-range links. Channel estimation is also corrupted by background and electrical noise. Accurate estimation of channel parameters and scintillation index (SI) depends on perfect removal of background irradiance. In this paper, we propose three different methods, the minimum-value (MV), mean-power (MP), and maximum-likelihood (ML) based methods, to remove the background irradiance from channel samples. The MV and MP methods do not require knowledge of the scintillation distribution. While the ML-based method assumes gamma–gamma scintillation, it can be easily modified to accommodate other distributions. Each estimator’s performance is compared using simulation data as well as experimental measurements. The estimators’ performance are evaluated from low- to high-SI areas using simulation data as well as experimental trials. The MV and MP methods have much lower complexity than the ML-based method. However, the ML-based method shows better SI and background-irradiance estimation performance.

© 2013 Optical Society of America

**OCIS Codes**

(350.4600) Other areas of optics : Optical engineering

(200.2605) Optics in computing : Free-space optical communication

**ToC Category:**

Optics in Computing

**History**

Original Manuscript: November 28, 2012

Revised Manuscript: February 27, 2013

Manuscript Accepted: March 24, 2013

Published: May 6, 2013

**Citation**

Afsana Khatoon, William G. Cowley, Nick Letzepis, and Dirk Giggenbach, "Estimation of channel parameters and background irradiance for free-space optical link," Appl. Opt. **52**, 3260-3268 (2013)

http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-52-14-3260

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