scholarly journals Effect of Atmospheric Turbulences on BPSK

2021 ◽  
Vol 10 (5) ◽  
pp. 353-357
Author(s):  
Priyanka Bhardwaj ◽  
Aadi Jain ◽  
Manveen . ◽  
Richita Kamal ◽  
Rishab Chittlangia
Keyword(s):  
Open Space ◽  
Signal To Noise Ratio ◽  
Modulation Scheme ◽  
Free Space Optical ◽  
Air Turbulence ◽  
And Performance ◽  
Log Normal ◽  
Negative Exponential ◽  
The Impact ◽  
Bpsk Modulation

FSO (Free-Space Optical Communications) is a type of optical communication that is transmitted over an open space. The irradiance fluctuation in a clear atmosphere is caused by Temperature variations in the atmosphere are minor but erratic. As a result, the Signal-to-Noise Ratio (SNR) is reduced, and performance is reduced. BPSK has the best performance when scintillation is not considered. Thus, BPSK is investigated in this work under the impact of air turbulence and meteorological variables. The comparison of BPSK modulation scheme is done by simulating turbulence in Log Normal and Negative Exponential Channel.

scholarly journals Analysis of signal quality in FSO systems with PolSK modulation

2020 ◽  
Vol 17 (2) ◽  
pp. 171-186
Author(s):  
Jelena Todorovic ◽  
Branimir Jaksic ◽  
Petar Spalevic ◽  
Djoko Bandjur ◽  
Milos Bandjur
Keyword(s):  
Signal To Noise Ratio ◽  
Free Space Optical ◽  
Link Distance ◽  
Negative Exponential Distribution ◽  
Shift Keying ◽  
Negative Exponential ◽  
Atmospheric Channel ◽  
Polsk Modulation ◽  
The Impact

In this paper, the quality of the Polarization Shift Keying (PolSK) modulated signal in a Free Space Optical (FSO) system is analyzed. The atmospheric channel is statistically modeled with four different distributions, namely, the Gamma-Gamma distribution, Negative Exponential distribution, Kdistribution, and I-K distribution. For all four channel models, the Average Bit Error Rate (ABER) at the receiving side of the system is determined in an analytically closed form. The results are graphically presented and discussed in order to determine the impact of certain parameters on the ABER, i.e., the quality of the received signal in the PolSK modulated FSO system. These parameters are the Signal-to-Noise Ratio (SNR), the FSO link distance, the wavelength at which the signal is transmitted, and the atmospheric turbulence strength.

Statistical evaluation of the performance of free-space-optical link affected by optical turbulence with gamma-gamma distribution through time series generated by simulation

2021 ◽  
Vol 67 (1 Jan-Feb) ◽  
pp. 146
Author(s):  
J. A. Lopez-Leyva ◽  
A. Arvizu-Mondragon ◽  
J. Santos-Aguilar ◽  
F. J. Mendieta-Jimenez
Keyword(s):  
Time Series ◽  
Gamma Distribution ◽  
Statistical Evaluation ◽  
Signal To Noise Ratio ◽  
Optical Power ◽  
Practical Implementation ◽  
Free Space Optical ◽  
Optical Turbulence ◽  
The Mean ◽  
The Impact

In this article, the statistical evaluation of the performance of FSO links subject to dynamic fluctuations of atmospheric optical turbulence that affect the instantaneous value of the received optical power is presented. We reproduce this temporal domain effect with time series generated by simulation considering the optical turbulence as a stochastic process with Gamma-Gamma probability distribution. Also, a phase screen was used in order to observe the impact that optical turbulence has over the optical information field's spatial phase. With our simulations, it is possible to get the two most essential performance parameters required for the practical implementation of FSO links. We obtained the mean signal-to-noise ratio (SNR) and the mean bit error rate (BER) of FSO links affected by optical turbulence with Gamma-Gamma distribution.  The methodology presented in this paper may be readily used to design and implement real-world FSO links.

scholarly journals A Field Experiment to Improve Communications in a Product Engineering Department: The Nonterritorial Office

1973 ◽  
Vol 15 (5) ◽  
pp. 487-498 ◽  
Author(s):  
Thomas J. Allen ◽  
Peter G. Gerstberger
Keyword(s):  
Field Experiment ◽  
Open Space ◽  
Floor Plan ◽  
Work Related ◽  
Product Engineering ◽  
Engineering Department ◽  
Large Round ◽  
Open Floor ◽  
And Performance ◽  
The Impact

A year-long investigation was undertaken to determine the impact, of a radical new scheme of office layout on work-related behavior, communication, and performance. The office layout under investigation is best described as “nonterritorial”. It is an open floor plan arrangement, but goes far beyond the traditional open-space office, removing not only office walls, but most permanent stations as well. Employees (product engineers) work at large round tables, which are distributed through the office area, and may locate themselves anywhere that they wish on any given day, or at different times during a day. The experiment was successful to the extent that employees preferred the new arrangement over the traditional one- and two-person offices they had previously occupied and that communication within the department increased significantly. It was unsuccessful in that no measurable increase in departmental performance was registered over the period of the study.

scholarly journals Performance Analysis of Dual-Hop Mixed Power Line Communication/Free-Space Optical Cooperative Systems

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 230
Author(s):  
Manh Le-Tran ◽  
Sunghwan Kim
Keyword(s):  
Free Space ◽  
Signal To Noise Ratio ◽  
Power Line ◽  
Cumulative Distribution ◽  
Power Line Communication ◽  
Free Space Optical ◽  
Proposed Model ◽  
Space Optical Communication ◽  
Mixed Power ◽  
Log Normal

In this paper, we study a mixed cooperative communication system consisting of power line communication (PLC) and free-space optical communication (FSO) links, where the PLC link suffers from log-normal fading and is affected by both impulsive and background noises. Meanwhile, the FSO link undergoes Gamma-Gamma fading with both atmospheric turbulence and pointing errors. More specifically, we present closed-form expressions for the probability density function and the cumulative distribution function of the end-to-end signal-to-noise ratio of the proposed model. Consequently, the outage probability and the bit error rate (BER) performance are derived in terms of univariate Fox-H and bivariate Fox-H functions. Finally, the analytical results are verified using Monte Carlo simulations, providing useful insights into the capabilities of the proposed system.

scholarly journals Design and Performance Analysis of Probabilistically Shaped QAM Signals for Coherent FSO Systems with Gamma-Gamma Turbulence Channels

2021 ◽  
Vol 11 (21) ◽  
pp. 9805
Author(s):  
Ruotong Tian ◽  
Zhiyong Wu ◽  
Shuang Ma ◽  
Yucong Gu ◽  
Xueliang Li
Keyword(s):  
Error Rate ◽  
Simulation Method ◽  
Mass Function ◽  
Symbol Error Rate ◽  
Coded Modulation ◽  
Modulation Scheme ◽  
Probability Mass Function ◽  
Free Space Optical ◽  
Probability Mass ◽  
And Performance

Probabilistic shaping (PS) is a promising technique to approach the Shannon limit. In this paper, we design a practical coded modulation scheme based on PS to improve the capacity of coherent free-space optical (FSO) links with quadrature amplitude modulation (QAM), where the fading channel follows the Gamma-Gamma distribution. The aim of this paper is to optimize the probability mass function (PMF) of the QAM signal points to achieve the maximum channel capacity. Due to the complexity of the objective function, the heuristic algorithm was employed to solve the optimization problem. To the best of the authors’ knowledge, the closed-form pairwise error probability (PEP) is first derived with the non-uniform signals under the turbulence channel. In addition, we measure the average symbol error rate (SER) and post-FEC bit error rate (BER) by the Monte Carlo simulation method. The numerical simulation results of both capacity and BER show that the proposed PS scheme is better than the uniform distribution. The post-FEC BER results show that the proposed PS scheme provides significant gains compared with the uniform scheme.

scholarly journals Outage probability analysis for hybrid TSR-PSR based SWIPT systems over log-normal fading channels

2021 ◽  
Vol 11 (5) ◽  
pp. 4233
Author(s):  
Hoang Thien Van ◽  
Hoang-Phuong Van ◽  
Danh Hong Le ◽  
Ma Quoc Phu ◽  
Hoang-Sy Nguyen
Keyword(s):  
Outage Probability ◽  
Fading Channels ◽  
System Performance ◽  
Signal To Noise Ratio ◽  
Cooperative Relaying ◽  
Power Splitting ◽  
Amplify And Forward ◽  
Time Switching ◽  
Log Normal ◽  
The Impact

Employing simultaneous information and power transfer (SWIPT) technology in cooperative relaying networks has drawn considerable attention from the research community. We can find several studies that focus on Rayleigh and Nakagami-m fading channels, which are used to model outdoor scenarios. Differing itself from several existing studies, this study is conducted in the context of indoor scenario modelled by log-normal fading channels. Specifically, we investigate a so-called hybrid time switching relaying (TSR)-power splitting relaying (PSR) protocol in an energy-constrained cooperative amplify-and-forward (AF) relaying network. We evaluate the system performance with outage probability (OP) by analytically expressing and simulating it with Monte Carlo method. The impact of power-splitting (PS), time-switching (TS) and signal-to-noise ratio (SNR) on the OP was as well investigated. Subsequently, the system performance of TSR, PSR and hybrid TSR-PSR schemes were compared. The simulation results are relatively accurate because they align well with the theory.

Modeling C2n by Inclusion of Rainfall Parameter and Validate Modified Log Normal and Gamma-Gamma Model on FSO Communication Link

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Suresh Kumar ◽  
Payal Arora
Keyword(s):  
Path Loss ◽  
Index Structure ◽  
Communication Link ◽  
Eastern Region ◽  
Free Space Optical ◽  
Gamma Model ◽  
Communication Performance ◽  
Log Normal ◽  
Fail Safe ◽  
The Impact

AbstractThe Log Normal model for weak turbulences and Gamma-Gamma model for moderate to strong turbulences are being used for calculating the path losses for engineering Free Space Optical (FSO) communication link. Since FSO has been an attractive substitute to overcome the issues of RF spectrum license, high infrastructure cost and difficult terrains to ensure the availability of a network. Their application in mountainous and high density built up areas needs to be exploited. Atmospheric turbulence degrades the FSO communication performance arising due to variations in {{C}}_{{n}}^2{\ }(Refractive index structure parameter). Both these models have the limitation of NOT considering Rainfall parameter while calculating C_n^2. In this present paper we have included effect of Rainfall and presented the modified analytical model by re modeling C_n^2. To validate the impact, comparison of existing model and the modified path loss model has been presented using Meteorological (MET) data for a designed FSO communication link between geographically known mountainous locations of North eastern region of Arunachal Pradesh. The results emphasize that, the modified model is essential to ensure reliable and fail safe FSO link.

Performance Analysis of Amplify-and-Forward Relaying FSO/SC-QAM Systems over Weak Turbulence Channels and Pointing Error Impairments

2017 ◽  
Vol 39 (1) ◽  
Author(s):  
Ha Duyen Trung
Keyword(s):  
Atmospheric Turbulence ◽  
Communication Systems ◽  
Symbol Error Rate ◽  
Aperture Size ◽  
Free Space Optical ◽  
Amplify And Forward ◽  
Pointing Error ◽  
Log Normal ◽  
The Impact ◽  
Af Relaying

AbstractIn this paper, the end-to-end performance of free-space optical (FSO) communication system combining with Amplify-and-Forward (AF)-assisted or fixed-gain relaying technology using subcarrier quadrature amplitude modulation (SC-QAM) over weak atmospheric turbulence channels modeled by log-normal distribution with pointing error impairments is studied. More specifically, unlike previous studies on AF relaying FSO communication systems without pointing error effects; the pointing error effect is studied by taking into account the influence of beamwidth, aperture size and jitter variance. In addition, a combination of these models to analyze the combined effect of atmospheric turbulence and pointing error to AF relaying FSO/SC-QAM systems is used. Finally, an analytical expression is derived to evaluate the average symbol error rate (ASER) performance of such systems. The numerical results show that the impact of pointing error on the performance of AF relaying FSO/SC-QAM systems and how we use proper values of aperture size and beamwidth to improve the performance of such systems. Some analytical results are confirmed by Monte-Carlo simulations.

Performance Analysis of FSO DF Relays with Log-Normal Fading Channel

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Ha Duyen Trung
Keyword(s):  
Performance Analysis ◽  
Error Rate ◽  
Communication Systems ◽  
Free Space Optical ◽  
Error Performance ◽  
Relay Nodes ◽  
Decode And Forward ◽  
Log Normal ◽  
Optimal Average ◽  
The Impact

AbstractThis paper studies the bit error performance analysis of decode-and-forward (DF) relays-based free-space optical (FSO) communication systems using avalanche photodiode (APD). The system uses subcarrier intensity binary phase shift keying (BPSK) modulated signals and subjects to scintillation due to optical turbulence. A log-normal random process is considered to model the received signal intensity fluctuation for a clear-air condition (weak atmospheric turbulence) scenario. Mathematical expressions of the average bit error probability and bit error rate (BER) are derived by taking into account the impact of atmospheric loss, thermal-noise and shot-noise limited conditions. It can be inferred from the numerical results that using DF relay nodes can extend the transmission distance and minimize BER performance of FSO system significantly compared with the direct transmission. Moreover, the selection of APD’s gain values is essential to minimize the system’s error rate performance. Therefore, the system could achieve the minimal BER by selecting an optimal average APD gain value appropriately. Moreover, the optimal average gain values of APD significantly depend on various conditions, such as the bit rate, total transmitted power, and the number of relay nodes.

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