Performance Analysis of FSO Links in Turbulent Atmosphere

2020 ◽  
pp. 100-156
Author(s):  
Banibrata Bag ◽  
Akinchan Das ◽  
Aniruddha Chandra ◽  
Rastislav Róka
Keyword(s):  
Atmospheric Turbulence ◽  
Communication Systems ◽  
Weather Conditions ◽  
Free Space Optical ◽  
Wireless Optical Communication ◽  
Adverse Weather Conditions ◽  
Adverse Weather ◽  
Optical Communication Systems ◽  
Active Research ◽  
Atmospheric Channel

The free-space optical communications technology is emerging as an attractive substitute to RF communications. It can satisfy the current demands for higher bandwidth to the customer. Atmospheric turbulence is a major obstacle in wireless optical communication systems. To fully utilize the terabit capacity of FSO system, it has to overcome various challenges offered by the heterogeneous nature of the atmospheric channel. Currently, FSO communication through atmospheric turbulence under adverse weather conditions is an active research topic. A lot of studies and experiments have been carried out on the effect of attenuation due to atmospheric turbulence; but still, much more research is necessary for fulfilling the current demands and commercial needs for implementing this technology successfully. This chapter discussed the various limitations of FSO system which are faced during data transmission through the atmospheric channel and various ways to improve the performance regarding BER, outage probability, and channel capacity.

Performance analysis of a hybrid FSO–FO link with smart decision making system under adverse weather conditions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Pradyut Mohapatra ◽  
Garima Singh ◽  
Anjali Singh ◽  
Gurjit Kaur
Keyword(s):  
Decision Making ◽  
Optical Fibers ◽  
Communication Systems ◽  
Weather Conditions ◽  
Wireless Communication Systems ◽  
Free Space Optical ◽  
Modulation Format ◽  
Adverse Weather Conditions ◽  
Adverse Weather ◽  
Decision Making System

Abstract Optical wireless communication systems employing free-space optical (FSO) links utilize modulated lasers to transmit information. FSO–fiber optic (FO) link provides an alternative possible way in scenarios where infrastructures employing optical fibers are widely destroyed due to disasters or when difficulties are faced during the installation of FO links. Furthermore, the link is integrated with decision-making ability. To encounter the distortions in the received signal carrier-suppressed return-to-zero modulation format has been used. FSO–FO hybrid link has been compared with simple FSO channel. The terrestrial links depend strongly on weather conditions as optical beams propagate through the atmosphere. Atmospheric attenuation could affect the FSO channel and has been considered to analyze the performance of the designed system.

scholarly journals Performance Investigation of OFDM-FSO System under Diverse Weather Conditions of Bangladesh

2018 ◽  
Vol 8 (5) ◽  
pp. 3722
Author(s):  
Maliha Sultana ◽  
Agnila Barua ◽  
Jobaida Akhtar ◽  
Mohammad Istiaque Reja
Keyword(s):  
Atmospheric Turbulence ◽  
Communication Systems ◽  
Weather Conditions ◽  
Index Structure ◽  
Propagation Path ◽  
Free Space Optical ◽  
Atmospheric Attenuation ◽  
Suitable Alternative ◽  
Pointing Error ◽  
Free Spectrum

Free space optical (FSO) communication systems which are deployed for last mile access, being considered as a suitable alternative technology for optical fiber networks. It is one of the emerging technologies for broadband wireless connectivity which has also been receiving growing attention due to high data rate transmission capability with low installation cost and license free spectrum. However, the widespread use of FSO technology has been hampered by the randomly time varying characteristics of propagation path mainly due to atmospheric turbulence, sensitivity to diverse weather conditions and the nonlinear responsivity of laser diode. This paper presents the performance investigation of an OFDM-FSO system over atmospheric turbulence channels under diverse weather conditions of Bangladesh. The channel is modeled with gamma-gamma distribution using 16-QAM modulation format and 4×4 multiple transceiver FSO system. All possible challenges are imposed on the system performance such as atmospheric attenuation, turbulence, pointing error, geometric loss etc. The refractive index structure parameter and atmospheric attenuation coefficient for different weather conditions are calculated by using the data, collected from Bangladesh Meteorological Department. The acquired results can be fruitful for scheming, forecasting and assessing the OFDM-FSO system’s ability to transmit wireless services over turbulent FSO links under actual conditions of Bangladesh.

scholarly journals Investigations of Free Space Optical Communications Under Real-World Atmospheric Conditions

2020 ◽  
Vol 116 (1) ◽  
pp. 475-490 ◽  
Author(s):  
Tobias Siegel ◽  
Shun-Ping Chen
Keyword(s):  
Optical Communications ◽  
Free Space ◽  
Communication Systems ◽  
New Technologies ◽  
Weather Conditions ◽  
Optical Systems ◽  
Limiting Factors ◽  
Atmospheric Conditions ◽  
Free Space Optical ◽  
Atmospheric Channel

AbstractDue to the increasing demand for higher bandwidth in modern communication systems, conventional networks are continuously expanded with new technologies to improve coverage. Free space optical communications (FSOC) shows some significant advantages concerning system setup time in comparison with the classical fiber optical systems on one hand, substantial spectral bandwidth and performances in comparison with the wireless systems under certain conditions on the other hand. This makes this technology not only a reasonable extension for metropolitan area networks but also provides the capability to set up a network after an outage in case of natural disaster quickly. But transmitting data by using FSOC involves some limiting factors that have to be considered prior to each installation. Since the atmospheric channel is not static, the influence of changing weather conditions or industrial smog have a significant impact on the available bitrate. A simulation platform is developed and presented in this paper for investigation of FSOC considering these circumstances. Regarding the atmospheric channel, turbulence, distance-dependent beam divergence, and applied modulation schemes, a general overview of the capabilities is presented and discussed. The insight of this paper should help to make a decision under which preconditions either the FSOC provides a meaningful application possibility, or the limiting factors become too crucial and other technologies must be considered.

Performance Enhancement of Atmospheric Coherent Optical Communication Systems Using DPSK

2012 ◽  
Vol 263-266 ◽  
pp. 1081-1084
Author(s):  
Yu Peng Li ◽  
Yan Gan Zhang ◽  
Xue Guang Yuan ◽  
Jin Nan Zhang ◽  
Ming Lun Zhang ◽  
...  
Keyword(s):  
Atmospheric Turbulence ◽  
Optical Communication ◽  
Communication Systems ◽  
Performance Enhancement ◽  
Signal To Noise Ratio ◽  
Free Space Optical ◽  
Eye Diagram ◽  
Optical Communication Systems ◽  
Simulation Results ◽  
Better Than

A coherent DPSK transmission system is presented to improve the receiver sensitivity for free space optical (FSO) communication. The coherent DPSK is an effective way to overcome the atmospheric turbulence. The eye diagram and bit error rate (BER) of the system are got by the simulation. Results show that with the coherent reception method, coherent DPSK offers improved signal-to-noise ratio (SNR) performance compared to the DPSK without coherent and OOK format. And hence it can be effective to overcome the signal impairment caused by atmospheric turbulence. It is shown that the sensitivity of the system employing coherent DPSK is 3dB better than a comparable system using DPSK without coherent and 9dB better than a system using OOK.

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