BPSK subcarrier intensity modulated free-space optical communications in atmospheric turbulence

Wasiu Oyewole Popoola, Zabih Ghassemlooy

Research output: Contribution to journalArticlepeer-review

470 Citations (Scopus)


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.
Original languageEnglish
Pages (from-to)967-973
JournalJournal of Lightwave Technology
Issue number8
Publication statusPublished - Apr 2009


Dive into the research topics of 'BPSK subcarrier intensity modulated free-space optical communications in atmospheric turbulence'. Together they form a unique fingerprint.

Cite this