Free-space optical communication with nonzero boresight pointing errors

Fan Yang, Julian Cheng, Theodoros A. Tsiftsis

Research output: Contribution to journalArticlepeer-review

180 Citations (Scopus)


The performance of free-space optical (FSO) communication systems is compromised by atmospheric fading and pointing errors. The pointing errors are widely considered as a combination of two components: boresight and jitter. A statistical model is investigated for pointing errors with nonzero boresight by taking into account the laser beamwidth, detector aperture size, and jitter variance. A novel closed-form probability density function (PDF) is derived for this new nonzero boresight pointing error model. Furthermore, we obtain closed-form PDF for the composite lognormal turbulence channels and finite series approximate PDF for the composite Gamma-Gamma turbulence channels, which is suitable for terrestrial FSO applications impaired by building sway. We conduct error rate analysis of on-off keying signaling with intensity modulation and direct detection over the lognormal and Gamma-Gamma fading channels. Asymptotic error rate analysis and outage probability of such a system are also presented based on the derived composite PDFs. It is shown that the boresight can only affect the coding gain, while the diversity order is determined by the atmospheric fading effect as well as the pointing error effect.

Original languageEnglish
Article number6712191
Pages (from-to)713-725
Number of pages13
JournalIEEE Transactions on Communications
Issue number2
Publication statusPublished - Feb 2014
Externally publishedYes


  • Free-space optical communications
  • lognormal fading
  • pointing errors

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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