Quantized Feedback-Based Differential Signaling for Free-Space Optical Communication System

Bhatnagar, Manav R.; Ghassemlooy, Zabih; Zvánovec, Stanislav; Khalighi, Mohammad-Ali; Abadi, Mojtaba Mansour

doi:10.1109/tcomm.2016.2614817

Cited by 33 publications

(15 citation statements)

References 25 publications

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“…Note that, unlike the metric of (13) which requires the calculation of a two-dimensional integral, the metric in (25), (26) only needs a series of simple additions and multiplications and also does not require the knowledge of f h (h). Here, the Rx searches among N s × 2 L+1 possible received sequences (i.e., 2 L+1 possible bit sequences for each sampler output) to find the sequence that minimizes (25). To avoid this exhaustive search and to further reduce the Rx complexity, we have developed a fast search algorithm for implementing (25), which reduces the search space to 4 N s L states.…”

Section: B Suboptimal Glrt-based Sequence Detection Methodsmentioning

confidence: 99%

“…Here, the Rx searches among N s × 2 L+1 possible received sequences (i.e., 2 L+1 possible bit sequences for each sampler output) to find the sequence that minimizes (25). To avoid this exhaustive search and to further reduce the Rx complexity, we have developed a fast search algorithm for implementing (25), which reduces the search space to 4 N s L states. Details of this algorithm are presented in Appendix.…”

Section: B Suboptimal Glrt-based Sequence Detection Methodsmentioning

confidence: 99%

“…Differential signaling is an innovative method that was firsty introduced in [21] to suppress the effect of background noise, and later proposed in [22], [23] to resolve the problem of detection threshold adjustment for OOK demodulation. It was also used in [24] to mitigate pointing errors effects, and in [25] to explore a onebit channel information scheme for a 2×1 FSO link. When the two wavelengths are sufficiently different, differential signaling can benefit from a diversity gain against channel fading [25].…”

Section: B Contributionsmentioning

confidence: 99%

“…It was also used in [24] to mitigate pointing errors effects, and in [25] to explore a onebit channel information scheme for a 2×1 FSO link. When the two wavelengths are sufficiently different, differential signaling can benefit from a diversity gain against channel fading [25]. As the fourth contribution, we propose an efficient blind detection scheme for such a scheme, albeit accepting an increased detection complexity.…”

Section: B Contributionsmentioning

confidence: 99%

“…Hence, for differential signaling with h 1 = h 2 , due to the symmetry of the received signals around zero, when h 1 tends to h 2 , γ th,opt → 0, as expected. Also, for the case of signal-independent noise at the Rx, this optimal value reduces to (h 1 + h 2 )/2, as considered in [25], [36].…”

Section: A Ber Analysis Under Pcsi and Psymentioning

confidence: 99%

See 4 more Smart Citations

Blind Signal Detection Under Synchronization Errors for FSO Links With High Mobility

Dabiri¹,

Sadough²,

Khalighi³

2019

IEEE Trans. Commun.

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We consider the use of free-space optical communication for fast moving platforms such as high-speed trains where the sampling clock offset is randomly changing and, in addition, the receiver does not have any information on the instantaneous channel fading coefficient. By employing multiple samplers at the receiver, we propose a class of sequence detection methods for the case of OOK signaling without using any training sequence. First, we study maximum likelihood based detection, which has a relatively high computational complexity. Second, by employing generalized likelihood ratio test, we propose a more practical blind sequence detection method of reduced complexity. To further reduce the computational complexity, third, we propose a novel scheme that uses two wavelengths at the transmitter and differential blind detection at the receiver. Fourth, to benefit from diversity gain with this differential scheme, we consider the use of sufficiently different wavelengths, where we propose an efficient blind detection method. The pros and cons of each proposed detection method are contrasted through numerical results and their processing load are compared as well.

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Section: B Suboptimal Glrt-based Sequence Detection Methodsmentioning

confidence: 99%

Section: B Suboptimal Glrt-based Sequence Detection Methodsmentioning

confidence: 99%

Section: B Contributionsmentioning

confidence: 99%

Section: B Contributionsmentioning

confidence: 99%

Section: A Ber Analysis Under Pcsi and Psymentioning

confidence: 99%

See 3 more Smart Citations

Blind Signal Detection Under Synchronization Errors for FSO Links With High Mobility

Dabiri¹,

Sadough²,

Khalighi³

2019

IEEE Trans. Commun.

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Image transmission performance analysis through free space optical communication link using coherent QPSK modulation under various environmental conditions

Djir

Meskine

Tayebi

2023

Trans Emerging Tel Tech

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Free space optics (FSO) technology has been used recently in many applications due to its various advantages such as high bandwidth, easy deployment, high security, free installation license and immunity to electromagnetic interference. However, this type of communication is vulnerable to meteorological conditions such as rain, haze and fog which significantly degrade the system's efficiency. To enhance the effectiveness of the FSO systems, Quadrature Phase Shift Keying (QPSK) modulation based on coherent detection constitutes a promising technique for achieving high spectral efficiency and long‐distance FSO links with the characteristics of low‐cost implementation and simple design. This work aims to investigate the performance of FSO communication links on image transmission under the presence of atmospheric attenuations. A comparative study has been made using QPSK modulation scheme and on–off‐keying (OOK) modulation scheme to estimate the maximum range that was used to recover an RGB transmitted image over an FSO link under different meteorological weathers. The obtained results clearly show that the quality of the received image has degraded significantly during transmission through free space yielding to limit the propagation range. Moreover, the proposed FSO communication system performs well when using QPSK modulation rather than OOK modulation in different environmental conditions. Thus, to improve the quality of the received image under adverse fog weather condition, high power and small beam divergence angle have been suggested to increase system's performance. The proposed solution increases the communication range of the FSO link by 230 m and 100 m for moderate and heavy fog, respectively.

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Designing an optimized free space optical (FSO) link for terrestrial commercial applications under turbulent channel conditions

et al. 2023

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Quantized Feedback-Based Differential Signaling for Free-Space Optical Communication System

Cited by 33 publications

References 25 publications

Blind Signal Detection Under Synchronization Errors for FSO Links With High Mobility

Blind Signal Detection Under Synchronization Errors for FSO Links With High Mobility

Image transmission performance analysis through free space optical communication link using coherent QPSK modulation under various environmental conditions

Designing an optimized free space optical (FSO) link for terrestrial commercial applications under turbulent channel conditions

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