A Simplified FSO Channel Model with Weak Turbulence and Pointing Errors

Free-space optical (FSO) links suffer from atmospheric turbulence and pointing errors. The probability density function (PDF) describing the distribution of the fading coefficient that models such effects is of great importance for designing FSO systems. In this paper, we present a simple closed-form approximation for this PDF in the weak turbulence regime. Our proposed approximation involves only exponential functions. This approximation is then used to develop two simple bit error rate expressions for on-off keying. Numerical results show excellent accuracy of the proposed expressions.