Study on statistical models of atmospheric channel for FSO communication link

In this paper, various channel models like the lognormal, negative exponential, gamma-gamma, K distribution and I-K distribution for frees space optical (FSO) link are reviewed. It is observed that for non-turbulent and weak turbulent channels, the BER performance at short wavelength is better than that at long wavelength for M-PPM signaling scheme. Also, the average power requirement decreases steadily with increase in M. For moderate turbulent channel, there is no significant change in the power level as the value of M is increased. However, in strong turbulent channels, there is a slight increase in the power level with the increase in M.