احمد کشاورز

In this paper, we study an adaptive subcarrier phase shift keying (PSK) intensity modulation for free space optical (FSO) communication systems, operating over Malaga atmospheric turbulence channel, which is a generalized statistical model proposed for FSO communications. According to the instantaneous state of turbulence-induced irradiance fluctuation and a target bit error rate (BER), the proposed transmission technique offers efficient utilization of the FSO channel capacity by exploiting adaptively the modulation order of subcarrier PSK. More precisely, closed-form expressions for the average BER of non-adaptive strategy, the achievable spectral efficiency and the average BER of proposed adaptive subcarrier PSK FSO system are derived in terms of the Meijer's G-function. Numerical results indicate that by using the proposed scheme, achievable spectral efficiency gain is offered without increasing the transmitted average optical power or sacrificing BER requirements.