Adaptive MIMO-FSO Space Diversity MRC Reception Characteristics over Malaga Turbulence Channel with Pointing Errors

Atmospheric turbulence channels experience quasi-static fading, making it relatively easy to use feedback information for link adaptive transmission. Applying adaptive modulation to MIMO systems can effectively reduce the degradation of FSO signals under adverse turbulence conditions. In this paper, considering the joint influence of pointing error and Malaga distribution turbulence fading, the probability density function (PDF) of the received light intensity of MIMO channel employing maximum ratio combining (MRC) is derived based on the generalized power series. Using the cumulative density function (CDF)-based method, We analyze the asymptotic spectral efficiency(SE) and average bit error rate (BER) performance of the adaptive MPSK-MIMO systemunder different turbulence intensities, beam waist radius, jitter standard deviation and aperture number. In addition, we compare the BER performance of adaptive with non adaptive MIMO systems using MRC receiver. Monte Carlo simulation further verify our analysis. The derived results help quantifying the diversity order of our considered systems.