Error performance enhancement of satellite to earth FSO downlink employing hybrid subcarrier intensity modulation scheme with aperture averaging technique

Performance enhancement of hybrid‐SIM for optical wireless downlink communication with aperture averaging and receiver diversity

“…The signal does not face turbulence when it is travelling in space. Upon reaching the ground station, the scintillation is approximated by a plane wave model [7, 9].…”

“…According to [7, 9, 23], increasing the diameter of the receiver reduces the scintillation index; this method of performance enhancement is known as AA. AA shifts the frequency content of the irradiance spectrum to the low spatial frequencies.…”

“…Nevertheless, aperture size cannot be increased indefinitely as using a single large aperture at the receiver side introduces background noise which causes deep fade in the signal. Also, apertures with a diameter >16 cm are not commercially available [7]. Spatial diversity is a promising solution to this issue [25].…”