Moment-Based Estimation for Gamma-Gamma Fading Parameters in Free-Space Optical Links

In this paper, accounting for the effect of noise, we propose a moment-based estimation method for the Gamma-Gamma fading parameters in free-space optical (FSO) links and analyze its estimation performance. The proposed method iteratively estimates the parameters of the Gamma-Gamma fading channel by minimizing the weighted sum of the moment differences, where these differences are obtained by employing from the first to fifth order moments. In particular, by updating each weight of the moment differences for every iteration, the proposed method simultaneously can give more accurate estimates of the parameters. Through computer simulations over a wide range of FSO channel conditions, we demonstrate that the proposed method outperforms the existing moment-based method in noisy environment, especially in low signal-to-noise ratio scenarios and for large values of the Rytov variances.