Free-Space Optical Communications Over Lognormal Fading Channels Using OOK With Finite Extinction Ratios

Free-Space Optical Communications Over Lognormal Fading Channels Using OOK With Finite Extinction Ratios

Free-space optical communication links operating over lognormal turbulence channels using on-off keying (OOK) are studied in this paper. Such systems can suffer from irreducible error floors that result from the use of demodulation with fixed and unoptimized detection thresholds. The resulting error...

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Bibliographic Details
Main Authors: Luanxia Yang, Xuegui Song, Julian Cheng, Jonathan F. Holzman
Format: Article
Language:English
Published: IEEE 2016-01-01
Series:IEEE Access
Subjects:
Atmospheric turbulence
optical wireless communications
on-off keying
Online Access:https://ieeexplore.ieee.org/document/7389967/
Description
Summary:Free-space optical communication links operating over lognormal turbulence channels using on-off keying (OOK) are studied in this paper. Such systems can suffer from irreducible error floors that result from the use of demodulation with fixed and unoptimized detection thresholds. The resulting error floors are analyzed for the general case of low- and high-state offsets (i.e., finite extinction ratios). An electrical signal-to-noise ratio (SNR) optimized detection system is applied. The system uses the electrical SNRs to implement adaptive detection thresholds and eliminate the error floors. The system can accommodate operation with finite extinction ratios, as it uses the method of moments and maximum likelihhod estimation techniques to estimate the low- and high-state offsets and electrical SNR. Numerical results show that the SNR gap between the electrical-SNR-optimized detection system and the adaptive detection system is 2.3 dB at a bit-error rate of 10<sup>-5</sup> without a state offset. The SNR gap increases to 4.5 dB with a state offset of &#x03BE;=0.2 .
ISSN:2169-3536

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