TY - JOUR
T1 - BPSK subcarrier intensity modulated free-space optical communications in atmospheric turbulence
AU - Popoola, Wasiu Oyewole
AU - Ghassemlooy, Zabih
PY - 2009/4
Y1 - 2009/4
N2 - Free-space optical communications (FSO) propagated over a clear atmosphere suffers from irradiance fluctuation caused by small but random atmospheric temperature fluctuations. This results in decreased signal-to-noise ratio (SNR) and consequently impaired performance. In this paper, the error performance of the FSO using a subcarrier intensity modulation (SIM) based on a binary phase shift keying (BPSK) scheme in a clear but turbulent atmosphere is presented. To evaluate the system error performance in turbulence regimes from weak to strong, the probability density function (pdf) of the received irradiance after traversing the atmosphere is modelled using the gamma-gamma distribution while the negative exponential distribution is used to model turbulence in the saturation region and beyond. The effect of turbulence induced irradiance fluctuation is mitigated using spatial diversity at the receiver. With reference to the single photodetector case, up to 12 dB gain in the electrical SNR is predicted with two direct detection PIN photodetectors in strong atmospheric turbulence.
AB - Free-space optical communications (FSO) propagated over a clear atmosphere suffers from irradiance fluctuation caused by small but random atmospheric temperature fluctuations. This results in decreased signal-to-noise ratio (SNR) and consequently impaired performance. In this paper, the error performance of the FSO using a subcarrier intensity modulation (SIM) based on a binary phase shift keying (BPSK) scheme in a clear but turbulent atmosphere is presented. To evaluate the system error performance in turbulence regimes from weak to strong, the probability density function (pdf) of the received irradiance after traversing the atmosphere is modelled using the gamma-gamma distribution while the negative exponential distribution is used to model turbulence in the saturation region and beyond. The effect of turbulence induced irradiance fluctuation is mitigated using spatial diversity at the receiver. With reference to the single photodetector case, up to 12 dB gain in the electrical SNR is predicted with two direct detection PIN photodetectors in strong atmospheric turbulence.
KW - gamma-gamma distribution
KW - negative exponential distribution
KW - probability density function
KW - random atmospheric temperature fluctuations
KW - receiver
KW - signal-to-noise ratio
KW - spatial diversity
KW - subcarrier intensity modulation
KW - two direct detection PIN photodetectors
U2 - 10.1109/JLT.2008.2004950
DO - 10.1109/JLT.2008.2004950
M3 - Article
SN - 0733-8724
VL - 27
SP - 967
EP - 973
JO - Journal of Lightwave Technology
JF - Journal of Lightwave Technology
IS - 8
ER -