310 / 2017-02-15 19:08:06

Performance Analysis of SIM based FSO using various modulation techniques with APD receiver over Turbulent Channel

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In this work, we have carried out a theoretical analysis on various subcarrier-intensity modulation (SIM) based techniques employed for free space optical wireless communication systems (FSO). APD receiver is included in our study to get more appropriate analysis of the system bit error rate (BER) performance. A comparative analysis of several modulation schemes i.e. binary phase shift keying –subcarrier intensity modulation(BPSK-SIM), differential phase shift keying- subcarrier intensity modulation (DPSK-SIM) and quadrature amplitude modulation- subcarrier intensity modulation (QAM-SIM) in optical wireless communication has been presented with respect to the average received irradiance. Moreover, a thorough investigation considering the channel attenuation factor has been included in this paper .The BER expressions are theoretically derived for the case of weak and moderate turbulent conditions using log-normal channel modelling. A detailed analysis of BER performance for the aforementioned modulation techniques is observed by varying the link distance , strength of turbulence and bit rate .