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Atmospheric attenuation vs. visibility for 850, 1250 and 1550 nm wavelengths in different weather conditions.
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Free Space Optical (FSO) communication is a very recent and emerging technology to establish broadband
wireless data transmission system using modulated optical beams. The adoption of FSO system is mainly
needed when any physical connection between the transmitter and receiver is practically impossible and
where high bandwidth data transmission is...
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In this paper, using simulation in the software OptiSystem 7.4, the FSO (Free Space Optical) system operating at wavelengths of 850 nm, 1315 nm and 1550 nm was observed. The influence of different levels of atmospheric turbulence and link distance on the signal transmission quality was investigated. The Q factor and BER (Bit Error Rate) were used a...
Citations
... Including γ C can also compensate for the underestimation of scintillation attenuation. From [23,Section 5 ...
Existing models for Radio Frequency (RF) and Free Space Optical (FSO) attenuations, such as the recommendations published by the International Telecommunication Union (ITU), require physical parameters along the communication channels. In practice, the weather parameters of the entire path are usually unavailable. This paper presents RF and FSO attenuation models built using machine learning algorithms and applied to empirical data. The empirical data consists of weather parameters collected at one end of the channel. Seven pairs of RF/FSO models are trained for specific weather conditions. The importance of each weather parameter is compared. RF attenuation is found to be sensitive to humidity, while FSO attenuation is closely related to scintillation. This paper shows how to obtain a pair of generic random forests that are applicable to seven specific weather conditions. The generic random forests predict the RF and FSO attenuations which have a joint distribution similar to the empirically observed distributions. They preserve the correlation between the RF and FSO attenuations as measured by the correlation coefficient and mutual information. When applied to empirical data, the generic random forests outperform the ITU models and models constructed by linear regression with interaction, both in terms of Root-Mean-Square-Error and R-squared.
... All the works discussed above are single input single output (SISO) FMCW photonic radar systems and are limited only to monostatic radar measurement, which can estimate the range [48] V = (10−20) km and velocity of the stationary and moving target. However, the photonic radar's capabilities, such as high azimuth resolution and more accurate target estimation, are unattainable with a single receiver. ...
... where P t is the transmitted power of the optical signal, ρ t is target reflectivity, D is the aperture diameter of the receiving telescope lens, R is the target range, cos(ϕ) is a Lambertian term employed to model a target's spectrality, and η is the efficiency of the receiver. The exponential exp(−2σ R) term is used to analytically model various atmospheric attenuation in the free space optical link, where σ is the atmospheric attenuation coefficient [48], and τ ntm is the round trip time delay from receiver node m receiving the radar response from target t of the transmitted signal from transmitter node n given as [42] ...
In this paper, a FMCW-based cooperative $2 \times 2$ 2 × 2 MIMO photonic radar system using heterodyne detection is presented. The proposed system consists of two separate sensor nodes that use a linear frequency modulated continuous wave signal, which allows simultaneous monostatic and bistatic radar measurement, where the target range and angle of arrival information are extracted. The additional bistatic information enhances the target detection and estimation capabilities with improved accuracy. This accuracy in practicality is affected by the laser phase noise, which degrades the overall system performance. Here, the analytical laser phase noise model for the MIMO system is derived and implemented to analyze its impact on the ranging accuracy of the proposed system. Under the impact of standard white Gaussian laser phase noise assumption, the monostatic and bistatic response of the detected signal is measured and compared using statistics of measurement error. Further, the signal-to-noise ratio and SSB laser phase noise of the monostatic and bistatic response are measured and compared at different target ranges. At last, the phase-noise-limited ranging accuracy of the system is evaluated and analyzed. The concept shown in this work paves the way for advanced photonic radar system applications such as modern radar systems, electronic warfare systems, metrology, and automotive vehicle radar with multiperspective coherent detection.
... We wish to develop test protocols and associated metrics to measure the performance of lidars under varying weather conditions, such as fog (the international definition of fog is visibility <1 km (35 db∕km attenuation at 0.5 km, visibility ∼92.3% transmission at 10 m) and mist is visibility between 1 and 2 km (8 db∕km attenuation at 1.5 km, visibility ∼98.2% transmission at 10 m) 18 and rain (rain intensity is defined by the US Geological Survey as light rain falling at <0.5 mm∕h, moderate rain between 0.5 and 4.0 mm∕h, heavy rain between 4.0 and 8.0 mm∕h, and very heavy rain in excess of 8.0 mm∕h 19 ). We will implement repeatable test conditions that simulate weather events for the duration of the test and maintain uniformity across the testing platform and evaluate lidar performance by measuring the reflectivity of chosen targets under various test conditions at various fog and rain intensities. ...
... Two bi-directional FSOs are compared as case study in the middle east region [5]. The effect of visibility and operating wavelengths on atmospheric attenuation has been addressed [10]. Cipher algorithm has been developed to produce the ciphered image. ...
This work investigates the integration of Electrical to Optical (E/O) and Optical to Electrical (E/O) communication systems. Two ways of transition, namely, Hybrid Fiber Optic (FO) and Free Optical Space (FSO) transmission system have been proposed. This work aims to evaluate the performance of these two transition ways. FO has the optimum transmission due to its lower attenuation which can be reached to 350 km. However, for further assurance of reaching data to the receiver side a second way of transition has been investigated. FSO path has been employed under different weather conditions of clear, moderate dust, heavy dust and heavy fog. Matlab and Optisystem7 software’s have been used to simulate Optical Secure Data Transition (SDT). The results show that an optimum transmission could be obtained using FO with RGB image encryption where the Mean Square Error (MSE) reach to 9.88 ×10^7 in read channel and it can reach to 4.93 ×10^9 using Discrete Wavelet Transform (DWT).
... according to the standard "Kim Model," the parameter q refers to the distribution size of the reflecting particles [17] Non-return to zero (NRZ) line coding is used to modulate these frequency spectra, and binary data is created at 2.5 Gb/s per channel. NRZ-OOK modulation scheme is used to make the system's simplicity. ...
Free Space Optics (FSO) is one of the most effective solutions for high-speed wireless communication under air turbulence or environmental hazard, while radio over fiber (RoF) shows better performance for long-distance communication. Wavelength division multiplexing (WDM) is the most effective method for multi-channel fiber to the home (FTTH) networks. The main objective of this study is to integrate the system performance with RoF and FSO links in order to improve network flexibility and expand the wireless network's coverage in the presence of weather hazards. The signal is generated by an array of optical lasers in the simulation and propagates through a maximum 3 km WDM-FSO link and a long fiber optic backhaul. As a result, each WDM channel can transmit 2.5 Gb/s data, getting a total data rate of 40 Gb/s using 16 WDM channels with a channel spacing of 100 GHz (0.8 nm). Finally, in order to improve the system performance, different optical amplifiers such as EDFA, SOA, and Raman are used in this hybrid WDM network.
... where denotes wavelength of transmitted light in nanometers, v points out the available visibility in kilometer units, and q shows the size distribution of the atmospheric particles which causes the scattering which in turn produces the attenuation [7]. A reference wavelength of 550 nanometers used as 0 for visibility calculation. ...
... Fog is the most aggressive variable to the FSO connection that has almost the same wavelength as light wavelength owing to the fog particles [16]. The atmospheric attenuation coefficient is calculated depending on visibility and wavelength by the equation of the incident beam [21]. ...
Free space optical (FSO) communications are the most promising sector in the near future of the communications technologies. That is due to its capability for satisfying the end user needs such as higher bandwidths for supporting high speed and better performance communications. This thesis evaluates the environmental parameters impact on the wireless optical communications behavior. It considers the most significant parameters such as rain, fog, haze, snow, and dust. The proposed system is modeled and implemented using opti-system package. The atmospheric attenuation profile according to both the visibility and the operational wavelengths for FSO connection for various weather conditions will be estimated. The maximum distance between the transmitter and the receiver will be discussed for various weather circumstances. The system analysis showed the improved efficiency of multi input/multi output (MIMO) settings compared to single input/single output (SISO) at various weather conditions. Furthermore, the interdependence of the most effective parameters in terms of both maximum distances and the link attenuation will be presented.
... The advantages of AOCL over existing communication lines are considered, including ease of installation, noise immunity, energy efficiency and the negative effect of the atmosphere on the laser beam. The influence of smoke and fog in the climate of Malaysia is studied in [9], rain, fog and scintillation state [10,11]. ...
... To solve this problem, in [6,7] it is proposed to increase the number of reception and transmission devices by 4 times and 2 times, but this will lead to a rise in price of such a system by 4 and 2 times, respectively. In [9][10][11], the attenuation of the power of a laser beam is studied under conditions of turbulence of the atmosphere of different terrain, which causes beam deformation of various types, as shown (Fig. 2). ...
... Also, most of the known works do not mention the problem of loss of communication due to the need to adjust the position of the receiver. For example, during the operation of satellite-to-ground AOCL, a constant adjustment of the position of the receiving device relative to the position of the transmitter is necessary, for which the exit of the laser beam beyond the limits of the receiving lens will lead to a complete loss of communication [6][7][8][9][10][11]. ...
... The rain, fog, and scintillation state effects are studied clearly in [8] at wavelength=1310 nm. The haze and fog state effects are studied clearly in [9,10]. The rain and fog state effects are studied clearly in [11,12]. ...
... Fog is the most hostile factor to FSO link due to the fog particles which are having nearly the same wavelength as wavelength of light. The atmospheric attenuation coefficient is calculated depending on visibility and the wavelength of the incident beam according to [9] ...
Free space optical communication systems are the future of the communication systems which can meet the needs of the end users who are demanding high bandwidths to support high-speed communication. These merits are due to its numerous advantages as well as their better performance. This paper studies the effect of environmental parameters like rain, fog, haze, snow, and dust on the performance of optical wireless communications using Opti-system program. This work considers the effect of visibility as well as operating wavelengths on atmospheric attenuation in different weather conditions for free space optical link. For different weather conditions the max distance between transmitter and receiver can also be estimated. The system analysis depicted the better performance of the Multi-Input/Multi-Output (MIMO) configurations compared to Single Input/Single Output (SISO) at different weather conditions.
... Heavy fog and snow also have a severe impact on such links. Various studies had been done by different research groups to enhance the data rate of an FSO system and proposed techniques to tackle the environmental turbulences [2][3][4][5][6][7][8][9]. Recently, Kumar studied the effect of various parameters such as OSNR, transmitter and receiver aperture, pointing error angles, relative intensity noise (RIN) on a High-Altitude Platform (HAP) to satellite link based on simulation. ...
The performance of a 120 Gbps single-carrier coherent transceiver system is evaluated in a terrestrial Free Space Optical Link (FSOL) under the haze, rain, and fog weather conditions. In-phase and Quadrature (IQ) based Dual Polarization 16 Quadrature Amplitude Modulation (DP-16-QAM) is implemented in OptiSystem v.13 simulation platform with homodyne detection and Digital Signal Processing (DSP) at the receiver. The IQ based optical modulator and the DSP unit can be fabricated in the form of Integrated Circuits (ICs) help to keep the system cost low. The system performance is evaluated in terms of Optical Signal to Noise Ratio (OSNR) requirements at an acceptable Bit Error Rate (BER ≤ 2 × 10^-3, i.e., below the FEC limit) under low turbulence environment. Simulation results show that the system maintains good OSNR performance under severe weather conditions. This transceiver system shall be useful in short-reach, low-cost, high-capacity, robust communication link with dynamic environmental conditions.
Full-text link: https://authors.elsevier.com/a/1XyMN6wQfGz9D
