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In this paper, we have shown the advantage of using 4-ary pulse position modulation (PPM) using intensity modulation with direct detection (IM/DD) as a power efficient system over coherent differential phase shift keying (DPSK) as a bandwidth efficient system in free space optical (FSO) weak turbulence channel (log-normal channel) and strong turbulence(More)
— Atmospheric turbulence induced fading is one of the main impairments affecting the operation of free-space optical (FSO) communication systems. In this paper, the bit error rate (BER) of M-ary pulse position modulation (M-ary PPM) of direct-detection and avalanche photodiode (APD) based is analyzed. Both log-normal and negative exponential fading channels(More)
In [1], the probability of error was computed for APD receivers. Due to an unintentional error, the square-root was omitted from the expression for the error rates in Eqs. (13) and (20) of ref. [1]. Hence, the correct expressions for the error rate are as follows: í µí±ƒ í µí± ≈ 1 √ í µí¼‹ í µí± ∑ í µí±–=−í µí± ;í µí±–∕ =0 í µí±¤ í µí±– í µí±„ ⎛ ⎝ √ í(More)
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