A survey on performance enhancement in free space optical communication system through channel models and modulation techniques

Anandkumar, D.; Sangeetha, R.

doi:10.1007/s11082-020-02629-6

Cited by 37 publications

(13 citation statements)

References 60 publications

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“…Therefore, the refractive index changes over time as it travels through the connection causing scintillations in the beam. The receiver detects these scintillations as a power fluctuation [13,14].…”

Section: 𝑦(𝑡) = 𝛾{ℎ(𝑡)𝑥(𝑡)} + 𝑛(𝑡)mentioning

confidence: 99%

Opto-Electronics Review

Lakshmi Priya,

Meenakshi

2022

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The explosive rise of wireless services necessitates a network connection with high bandwidth, high performance, low mistakes, and adequate channel capacity. Individual mobile users, as well as residential and business clusters are increasingly using the internet and multimedia services, resulting in massive increases in the internet traffic demand. Over the past decade, internet traffic has grown significantly faster than Moore's law predicted. The current system is facing significant radio frequency spectrum congestion and is unable to successfully transmit growing amounts of (available) data to end users while keeping acceptable delay values in mind. Free space optics is a viable alternative to the current radio frequency technology. This technology has a few advantages, including fast data speeds, unrestricted bandwidth, and excellent security. Since free space optics is invisible to traffic type and data protocol, it may be quickly reliably and profitably integrated into an existing access network. Despite the undeniable benefits of free space optics technology under excellent channel conditions and its wide range of applications, its broad use is hampered by its low link dependability, especially over long distances, caused by atmospheric turbulenceinduced decay and weather sensitivity. The best plausible solution is to establish a secondary channel link in the GHz frequency range that works in tandem with the primary free space optics link. A hybrid system that combines free space optics and millimeter wave technologies in this research is presented. The combined system offers a definitive backhaul maintenance, by drastically improving the link range and service availability.

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Section: 𝑦(𝑡) = 𝛾{ℎ(𝑡)𝑥(𝑡)} + 𝑛(𝑡)mentioning

confidence: 99%

Opto-Electronics Review

Lakshmi Priya,

Meenakshi

2022

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“…Water, carbon dioxide, and ozone molecules are the primary atmospheric absorbers [32]. The absorption of light by the atmosphere is a wavelength-dependent phenomenon.…”

Section: Absorption and Scattering Lossmentioning

confidence: 99%

New modeling approach of laser communication in constellation and through atmospheric disturbances

2021

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Laser communication between satellites in the constellation and from the satellites to ground stations offers a gigantic data rate for the users. This principal advantage drives telecom companies to develop this technology to use it like a carrier signal, the most disadvantage of this technology is the need to very complicated pointing systems between the transmitter and the receiver due to a very small beam divergence, continually moving of satellites in orbits and the distance between the satellites (tens of thousands of kilometers). The laser beam suffers continuously from several factors like atmospheric turbulences, internal and external vibrations. All these factors lead to an increase in the bit errors rate and cause degradation in the communication quality. This paper deals with a new method of modelisation of external effects in transmission of signal light from a ground station to the satellite through atmospheric disturbances. Indeed, an in-depth investigation, of the influences of satellite vibrationsinlaser signal transmission between satellites constellation, has been conducted by studying the effect of the intensity of vibrations on the optical signal amplitude. Some solutions are proposed to improve the efficiency of optical satellites communications.

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“…The FSO communication systems are unlicensed, Line of Sight (LOS) based systems, which usually utilizes Laser (700-1600nm) as carrier modulation and the transmission propagates through free space between source and destination [10]. However, the environmental constraints like absorption and scattering phenomenon attenuate the signal integrity [11]. The geometrical losses, pointing and tracking errors overshadows the FSO links' reliability, resultantly, reducing link range and the performance bit error rate (BER) [12].…”

Section: Introductionmentioning

confidence: 99%

Duplex Baseband Signal Transmission Over Free Space Optical Link Employing Carrier Reuse

Shamsi

2022

Preprint

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With increasing IoT and a plethora of multimedia applications being used, there is an ever-increasing demand for bandwidth-intensive applications. Communication networks employing optical fiber had been the de facto standard for such communication systems. The Optical Fiber network's high cost and man-hours required for laying demand wireless solutions. Therefore, an optimum and cost-effective duplex optical link for two channels baseband signal data transmission has been designed and validated using a single laser source. An optical link for 20 Gbps duplex data transmission is designed based upon single laser source utilization. A cost-efficient and simple design have been accomplished with a transmission distance of 1.5 km by utilizing Differential Quadrature Phase Shift Keying (DQPSK) and On-Off Keying (OOK) modulation techniques. The design allowed us to recycle the downlink signal in uplink transmission over free Space, thus eradicating the requirement for a separate laser at the other end. Each channel's transmission data rate was 10 Gb/sec. At the former end, the DQPSK technique was employed for data modulation and the data was transmitted into free space. The data was then split at the latter end for downlink reception along with reusing the downlink received signal for uplink transmission to the former end utilizing the OOK modulation technique. The received data was compared with the transmitted one to verify and validate the system's accuracy through signal waveforms and BER (Bit Error Rate). The eye diagrams and the Bit error rate (BER) graphs of the received downlink and uplink signals over a duplex Free Space Optical (FSO) transmission link are discussed and presented.

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A survey on performance enhancement in free space optical communication system through channel models and modulation techniques

Cited by 37 publications

References 60 publications

Opto-Electronics Review

Opto-Electronics Review

New modeling approach of laser communication in constellation and through atmospheric disturbances

Duplex Baseband Signal Transmission Over Free Space Optical Link Employing Carrier Reuse

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