scholarly journals Impact of pointing error on SISO/MISO drones swarm-based free space optical system in weak turbulence regime

2021 ◽  
Vol 23 (2) ◽  
pp. 918
Author(s):  
Abdullah Jameel Mahdi ◽  
Wamidh Jalil Mazher ◽  
Osman Nuri Ucan
Keyword(s):  
Free Space ◽  
Communication Systems ◽  
High Performance ◽  
Signal To Noise Ratio ◽  
Weather Conditions ◽  
Free Space Optical ◽  
Single Input Single Output ◽  
Pointing Error ◽  
Single Output ◽  
Link Distance

<p>Applying the drone-based free space optical (FSO) technology is recent in communication systems. The FSO technology hashigh-security features dueto narrow beamwidth, insusceptible to interferences, free license and landline connection is not appropriate. However, these advantages face many obstacles that affect the system's performance, such as random weather conditions and misalignment. The pointing error Hpis one of the critical factors of the channel gain H. The related parameters of the Hp factor: the pointing error angles θr and the path length Z, were manipulated to extract the applicable values at various receiver diameter values. The proposed system has two topologies: single input single output (SISO) and multiple input single output (MISO), flying in weak atmospheric turbulence. The simulation was done using MATLAB software 2020. The average bit error rate (ABER) for the system versus signal-to-noise ratio (SNR) were verified and analyzed. The results showed that at θr=10<sup>−3</sup>rad, Z increased in the range 10~100m for each one-centimeter increase of DR. At θr=10<sup>−2</sup>rad, the applicable Z was nearly 10% of the link distance Z when θr=10<sup>−3</sup>rad was applied. Consequently, an increase in θr must correspond decrease in Z and vice versa to maintain the system at high performance.</p>

Effect of adverse weather conditions and pointing error on the performance of 2-D WH/TS OCDMA over FSO link

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Bithi Mitra ◽  
Md. Jahedul Islam
Keyword(s):  
Free Space ◽  
Atmospheric Condition ◽  
Optical Power ◽  
Weather Conditions ◽  
Free Space Optical ◽  
Central Wavelength ◽  
Pointing Error ◽  
Adverse Weather ◽  
Code Division Multiple ◽  
Ber Performance

AbstractIn this paper, the performance of two-dimensional (2-D) wavelength-hopping/time-spreading (WH/TS) optical code division multiple access (OCDMA) system over free space optical (FSO) channel is analyzed in the presence of pointing error and different weather conditions. Prime code scheme is employed for both wavelength-hopping and time-spreading to address user code-matrix. The operating central wavelength of 1550 nm is considered to demonstrate the bit error rate (BER) performance of the proposed system as a function of various system parameters. The required optical power of the proposed system is determined to maintain a BER value of 10−9. The numerical evaluation interprets that the BER performance is highly dependent on transmission length, transmitted power, pointing error angle as well as the number of simultaneous user. It is also observed that the 2-D OCDMA system over free space needs minimum required optical power in case of rainy atmospheric condition, but it is maximum for foggy atmospheric condition.

scholarly journals Calculations of Signal to Noise Ratio (SNR) for Free Space Optical Communication Systems

2008 ◽  
Vol 5 (1) ◽  
pp. 95-100
Author(s):  
Baghdad Science Journal
Keyword(s):  
Optical Communication ◽  
Free Space ◽  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Full Duplex ◽  
Free Space Optical ◽  
Signal To Noise ◽  
Optical Communication Systems ◽  
Space Optical Communication ◽  
Noise Ratio

In this paper, we calculate and measure the SNR theoretically and experimental for digital full duplex optical communication systems for different ranges in free space, the system consists of transmitter and receiver in each side. The semiconductor laser (pointer) was used as a carrier wave in free space with the specification is 5mW power and 650nm wavelength. The type of optical detector was used a PIN with area 1mm2 and responsively 0.4A/W for this wavelength. The results show a high quality optical communication system for different range from (300-1300)m with different bit rat (60-140)kbit/sec is achieved with best values of the signal to noise ratio (SNR).

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 Utilization of MIMO Concept for Optical Communication System under Fog Condition

2019 ◽  
Vol 17 (2) ◽  
pp. 130-135
Author(s):  
Farouk Shakir ◽  
Mazin Ali A. Ali ◽  
Firas Ameer
Keyword(s):  
Mimo Systems ◽  
Signal To Noise Ratio ◽  
Optical Power ◽  
Cost Effective ◽  
Free Space Optical ◽  
Single Input Single Output ◽  
High Data ◽  
Single Output ◽  
Received Power ◽  
Single Input

Free-space optical (FSO) communication consider license free, high data rate, wide bandwidth and cost-effective. Multi-input Multi-output (MIMO) systems can be employed to reduce the attenuation by heavy fog and improve FSO channel capacity. In this paper a single-input single-output and multi–input multi-output examined to investigate the performance of these systems under heavy fog. A comparison is made in terms of received optical power, signal to noise ratio, and bit error rate (BER) using OptiSystem version 7.0. The signal reaches to link up to 1.7km, 1.55km, 1.5km, and 1.4km for 4Tx/4Rx, 3Tx/3Rx, 2Tx/2Rx, 1Tx/1Rxrespectively. The results showed that the quality of received power is enhancement by using up to four beams.

scholarly journals Optimal Power Allocation Between Beam Tracking and Symbol Detection Channels in a Free-Space Optical Communications Receiver

2020 ◽  
Author(s):  
Muhammad Salman Bashir ◽  
Mohamed-Slim Alouini
Keyword(s):  
Power Allocation ◽  
Free Space ◽  
Signal To Noise Ratio ◽  
Optimal Power Allocation ◽  
Free Space Optical ◽  
Signal To Noise ◽  
Pointing Error ◽  
Optimal Power ◽  
Received Power ◽  
Noise Ratio

Free-space optical (FSO) communications will play an important role in the backhaul of future generation of wireless networks in order to support high data rates. Because of narrow beamwidth inherent to an optical signal, acquisition and tracking form an important component of any FSO communication system. In this study, we have analyzed the optimization of received power allocation between tracking and data channels in an FSO receiver. The objective function that is optimized (minimized) are the probability of error and the probability of outage, and the optimization of power allocation is carried out as a function of parameters such as noise power, pointing error variance, pointing error correlation coefficient, and the threshold of outage. We have analyzed the optimization concerning the lognormal and exponentiated Weibull fading scenarios as well. We learn that the optimal power allocation is a function of the received signal-to-noise ratio: a lower signal-to-noise ratio dictates that a higher fraction of received power should be diverted to the tracking channel and vice versa.

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 analysis of free space optical system incorporating circular polarization shift keying and mode division multiplexing

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Meenu ◽  
Anshu Sharma ◽  
Rahul Malhotra
Keyword(s):  
Circular Polarization ◽  
Free Space ◽  
Heavy Rain ◽  
Weather Conditions ◽  
Detailed Comparison ◽  
Free Space Optical ◽  
Light Rain ◽  
Link Distance ◽  
Mode Division Multiplexing ◽  
Shift Keying

Abstract In this work, a free-space optical (FSO) communication system with the integration of mode division multiplexing and circular polarization shift keying (CpolSK) is proposed at 2 × 40 Gbps using LG00 and LG01 modes. Effects of diverse weather conditions such as clear weather, light rain, moderate rain, heavy rain, thin fog, thick fog, and heavy fog are studied on system performance. Further, a detailed comparison of CpolSK and polarization shift keying (PolSK) is performed at different FSO lengths in terms of log bit error rate. For implementation, analysis, and comparison, Optiwave Optisystem software is used and results show that CpolSK covers 100 km link distance and PolSK limits to 90 km only. Also, LG00 mode performs better than LG01 mode under all weather instabilities in the proposed system.

High-Speed 120 Gbps AMI-WDM-PDM Free Space Optical Transmission System

2019 ◽  
Vol 40 (4) ◽  
pp. 429-433 ◽  
Author(s):  
Kamal Kishore Upadhyay ◽  
Saumya Srivastava ◽  
N. K Shukla ◽  
Sushank Chaudhary
Keyword(s):  
Wavelength Division Multiplexing ◽  
Free Space ◽  
Communication Systems ◽  
High Speed ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Free Space Optical ◽  
Wavelength Division ◽  
Received Power ◽  
Polarization Division Multiplexing

Abstract Free space optical (FSO) communication systems are gaining high popularity from the last decade due to its various advantages such as no license spectrum, low-cost implementation etc. In this work, 160 Gbps data is transmitted over 8 km FSO link by adopting alternate mark inversion (AMI), wavelength division multiplexing (WDM) and polarization division multiplexing (PDM) schemes. The results are reported in terms of Q factor, bit error rate, signal to noise ratio, total received power and eye diagrams.

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