Stellar scintillation and the atmosphere’s vertical turbulence profile

Camparo, J. C.

doi:10.1364/josaa.18.000631

Cited by 8 publications

(3 citation statements)

References 15 publications

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“…It is also assumed that the laser beam propagates along a horizontal path in which the refractive index structure parameter C 2 n is constant. The method of multiple random phase screens 9,15,19 is used to simulate the turbulent atmosphere. The Kolmogorov spectrum 9 is used to generate the random phase screens.…”

Section: Introductionmentioning

confidence: 99%

On fading probability density functions of fast-tracked and untracked free-space optical communication channels

Zhao

Liao

2011

SPIE Proceedings

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Free-space optical (FSO) communication systems suffer from average power loss and instantaneous power fading due to the atmospheric turbulence. The channel fading probability density function (pdf) is of critical importance for FSO communication system design and evaluation. The performance and reliability of FSO communication systems can be greatly enhanced if fast-tacking devices are employed at the transmitter in order to compensate laser beam wander at the receiver aperture. The fast-tracking method is especially effective when communication distance is long. This paper studies the fading probability density functions of both fast-tracked and untracked FSO communication channels. Large-scale wave-optics simulations are conducted for both tracked and untracked lasers. In the simulations, the Kolmogorov spectrum is adopted, and it is assumed that the outer scale is infinitely large and the inner scale is negligibly small. The fading pdfs of both fast-tracked and untracked FSO channels are obtained from the simulations. Results show that the fast-tracked channel fading can be accurately modeled as gamma-distributed if receiver aperture size is smaller than the coherence radius. An analytical method is given for calculating the untracked fading pdfs of both point-like and finite-size receiver apertures from the fast-tracked fading pdf. For point-like apertures, the analytical method gives pdfs close to the well-known gamma-gamma pdfs if off-axis effects are omitted in the formulation. When off-axis effects are taken into consideration, the untracked pdfs obtained using the analytical method fit the simulation pdfs better than gamma-gamma distributions for point-like apertures, and closely fit the simulation pdfs for finite-size apertures where gamma-gamma pdfs deviate from those of the simulations significantly.

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Section: Introductionmentioning

confidence: 99%

On fading probability density functions of fast-tracked and untracked free-space optical communication channels

Zhao

Liao

2011

SPIE Proceedings

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“…It is assumed that the laser beam is well aligned and propagates along a horizontal path in which the refractive index structure parameter C 2 n is constant. The method of multiple random phase screens [9,15,30,31] is used to simulate the laser propagation in the turbulent atmosphere. The Kolmogorov spectrum [9] is used to generate the random phase screens and it is assumed that the outer scale is infinite large and the inner scale is negligibly small.…”

Section: Introductionmentioning

confidence: 99%

Reed-Solomon coding for free-space optical communications through turbulent atmosphere

Zhao

Liao

Lyke

et al. 2010

2010 IEEE Aerospace Conference

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The average power loss and the channel power fading are among the major challenges of the free-space optical (FSO) communications through the turbulent atmosphere, which result in severe bit-error-rate (BER) performance degradation, or even communication link outage. For the same average received optical signal power, the degradation in BER performance is strongly dependent on the fading statistics. This paper studies channel coding using the ReedSolomon (RS) codes for improving the FSO communication system performance and communication distance. Largescale numerical simulations have been conducted to obtain the channel fading statistics and average received power for different receiver aperture sizes and distances of focused laser beams along the horizontal paths. The avalanche photodiode (APD) photodetector is used for direct detection, and the accurate McIntyre-Conradi model is adopted for system performance evaluation. Under codeword symbol level channel interleaving, if the channel demodulator provides channel erasure information when the channel is in deep fades, the RS codes are able to achieve more than 13dB coding gain at BER = 10 −5 and more than 17dB coding gain at BER = 10 −6 . It is also shown that for relatively weak fading channels, the channel coding using the RS codes can achieve the BER performance almost identical to that of the corresponding ideal fading-free channel. The optimal receiver aperture sizes under channel coding are also studied.

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“…The resolution of the phase screen dx ranges from 0.625mm to 2.5mm. The resolution is much smaller than the corresponding coherence radius and satisfies the restrictions to accurately simulate the wavepropagation[56]. The iteration number M to directly simulate the fading pdf ranges from 0.3 million to 1 million.…”

mentioning

confidence: 99%

Fading pdf of free-space optical communication system with pointing error

Liao¹

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Stellar scintillation and the atmosphere’s vertical turbulence profile

Cited by 8 publications

References 15 publications

On fading probability density functions of fast-tracked and untracked free-space optical communication channels

On fading probability density functions of fast-tracked and untracked free-space optical communication channels

Reed-Solomon coding for free-space optical communications through turbulent atmosphere

Fading pdf of free-space optical communication system with pointing error

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