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An analytical approach is presented to evaluate the combined influence of atmospheric scintillation, backscattering and optical channel density on the bit error rate (BER) performance of an optical wireless link. The results evaluated at a bit rate of 500 Mbps shown that there is significant deterioration in bit error rate (BER) performance due to above system imperfections. For example, at a backscattering power of-90 dBm, the penalty due to only backscattering is approximately 4.5 dB which increases to almost 47.5 dB in the presence of scintillation with variance σs 2 of 0.1, which results in additional 43 dB power penalty due to atmospheric scintillation whereas it decreases to 33.5 dB, 28.5 dB, 23 dB, 18.5 dB and 13.5 dB corresponding to σs 2= 1e-2, 1e-3, 1e-4, 1e-5 and 1e-6 respectively. The atmospheric scintillation thus has a great impact on an optical free-space link which is much more prominent than the effect of backscattered power.