scholarly journals Analysis of Rain Effects on Terrestrial Free Space Optics based on Data Measured in Tropical Climate

2012 ◽  
Vol 12 (5) ◽  
Author(s):  
Suriza Ahmad Zabidi ◽  
Md. Rafiqul Islam ◽  
Wajdi Al-Khateeb ◽  
Ahmed Wathik Naji
Keyword(s):  
Fiber Optics ◽  
Free Space ◽  
Prediction Models ◽  
Tropical Climate ◽  
Rain Attenuation ◽  
Free Space Optics ◽  
Tropical Region ◽  
Communication Link ◽  
Free Space Optical ◽  
Space Optics

Free Space Optics (FSO) shows a great alternative as the solution for last mile problem where fiber optics is unavailable due to deployment time and cost constraint.  However, the feasibility of using FSO system as communication link very much depends on local weather.  Since tropical region experiences heavy rainfall, rain with high intensity is expected to affect the FSO link severely. Few prediction models have been proposed by ITU-R based on France and Japan’s measurement. This paper has compared  rain attenuation predicted by  models and  data measured in Malaysia over Free Space Optical links for one year period. Prediction models are clearly unable to predict attenuation measured in tropical climate. ABSTRAK: Wayarles optik menjadi alternatif sebagai satu penyelesaian kepada masalah kesesakan terutama diakhir sesuatu talian dimana ianya tidak dapat diselesaikan dengan menggunakan gentian fiber akibat daripada kekangan masa pemasangan dan masalah kewangan.  Walaubagaimanapun, kejayaan untuk menggunakan wayarless optic ini amat bergantung kepada keadaan cuaca di sesuatu tempat.  Di rantau tropika  hujan lebat sentiasa dialami, oleh itu hujan dengan kepadatan tinggi adalah dijangkakan lebih memberi kesan kepada talian wayarles optic ini. Beberapa model yang telah dicadangkan oleh ITU-R berlandaskan kepada pengumpulan data yang dibuat di Perancis dan Jepun.  Kertas kajian ini akan membandingkan antara model-model yang telah digunapakai dengan data yang dikumpulkan di Malaysia selama setahun.  Jelasnya model yang telah digunapakai tidak dapat digunakan secara berkesan di rantau tropika.KEYWORDS: free space optics; rainfall rate; rain attenuation

scholarly journals Feasibility Analysis Of Free Space Earth To Satellite Optical Link In Tropical Region

2012 ◽  
Vol 12 (5) ◽  
Author(s):  
Norhanis Aida M. Nor ◽  
Md. Rafiqul Islam ◽  
Wajdi Al-Khateeb
Keyword(s):  
Electromagnetic Interference ◽  
Free Space ◽  
Elevation Angle ◽  
Rain Attenuation ◽  
Low Earth Orbit ◽  
Feasibility Analysis ◽  
Free Space Optics ◽  
Tropical Region ◽  
Earth Orbit ◽  
Space Optics

Free Space Optics (FSO) becomes a great attention because of the chances in transmitting data up to 2.5Gbps. There are a lot of advantages offered by FSO such as easily deployment with saving time and cost and no electromagnetic interference. In spite of the advantages, FSO has an uncontrolled drawback which is highly sensitive to atmospheric phenomena because uses air as tranmission medium. Current studies and researches are only focusing on FSO terrestrial link with short path length and based on data from temperate region. Therefore, this paper is aiming to provide feasibility analysis of FSO link from earth to satellite especially Low Earth Orbit (LEO) based on atmospheric data in tropical region. The analysis will include the losses from geometrical attenuation, absorption, scintillation, haze attenuation, and rain attenuation. ABSTRAK: Ruang Bebas Optik (Free Space Optics (FSO)) mendapat perhatian kerana kebolehannya memancarkan data pada kelajuan tinggi. Di sebalik kelebihannya, FSO amat sensitif terhadap fenomena atmosfera kerana ia menggunakan udara sebagai perantara transmisi. Penyelidikan dan kajian terkini hanya memfokus kepada jalinan darat FSO dengan kepanjangan jarak pendek dan bergantung kepada kawasan tenang.  Oleh itu, kertas ini menyasarkan untuk memberikan analisis kebolehlaksanaan  jalinan FSO dari bumi ke satelit terutamanya Orbit Rendah Bumi (Low Earth Orbit (LEO)) bergantung kepada data atmosfera di kawasan tropika. Analisa termasuklah kehilangannya akibat pengecilan geometri, penyerapan, kelipan, pelemahan jerebu dan pelemahan hujan.KEYWORDS:  feasibility; Free Space Optics; availability; atmospheric attenuation; beam divergence angle; elevation angle

Modelling of 10 Gbps Free Space Optics Communication Link Using Array of Receivers in Moderate and Harsh Weather Conditions

2017 ◽  
Vol 38 (3) ◽  
Author(s):  
Amit Gupta ◽  
Nagpal Shaina
Keyword(s):  
Free Space ◽  
Weather Conditions ◽  
Quality Data ◽  
Laser Source ◽  
Communication Link ◽  
Free Space Optical ◽  
Space Optics ◽  
Received Power ◽  
Adverse Weather ◽  
The Impact

AbstractIntersymbol interference and attenuation of signal are two major parameters affecting the quality of transmission in Free Space Optical (FSO) Communication link. In this paper, the impact of these parameters on FSO communication link is analysed for delivering high-quality data transmission. The performance of the link is investigated under the influence of amplifier in the link. The performance parameters of the link like minimum bit error rate, received signal power and Quality factor are examined by employing erbium-doped fibre amplifier in the link. The effects of amplifier are visualized with the amount of received power. Further, the link is simulated for moderate weather conditions at various attenuation levels on transmitted signal. Finally, the designed link is analysed in adverse weather conditions by using high-power laser source for optimum performance.

Visibility effect on the availability of a terrestrial free space optics link under a tropical climate

2016 ◽  
Vol 143-144 ◽  
pp. 47-52 ◽  
Author(s):  
Ahmed Basahel ◽  
Islam Md. Rafiqul ◽  
Mohamad Hadi Habaebi ◽  
A.Z. Suriza
Keyword(s):  
Free Space ◽  
Tropical Climate ◽  
Free Space Optics ◽  
Space Optics

Improved Performance Analysis of Free Space Optics Communication Link under Rain Conditions using EDFA Pre-amplifier

2018 ◽  
Vol 39 (2) ◽  
pp. 241-246 ◽  
Author(s):  
Mehtab Singh
Keyword(s):  
Performance Analysis ◽  
Free Space ◽  
Weather Conditions ◽  
Fiber Amplifier ◽  
Free Space Optics ◽  
Communication Link ◽  
Erbium Doped Fiber Amplifier ◽  
Space Optics ◽  
Link Distance ◽  
Improved Performance

AbstractFree Space Optics (FSO) also known as Optical Wireless Communication (OWC) is a communication technology in which free space/air is used as the propagation medium and optical signals are used as the information carriers. One of the most crucial factors which degrade the performance of FSO link is the signal attenuation due to different atmospheric weather conditions such as haze, rain, storm, and fog. In this paper, an improved performance analysis of a 2.5 Gbps FSO link under rain conditions has been reported using Erbium-Doped Fiber Amplifier (EDFA) as a pre-amplifier. The results show that the maximum link distance for an FSO link under rain weather conditions with acceptable performance levels (Q$$\sim6$$and BER$$ \le {10^{- 9}})$$in the absence of EDFA pre-amplifier is 1,250 m which increases to 1,675 m with the use of EDFA pre-amplifier.

Mitigation of Atmospheric Turbulences Using Mode Division Multiplexing based on Decision Feedback Equalizer for Free Space Optics

2020 ◽  
Vol 41 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Abdullah Almogahed ◽  
Angela Amphawan ◽  
Yousef Fazea
Keyword(s):  
Free Space ◽  
Minimum Mean Square Error ◽  
Decision Feedback ◽  
Free Space Optics ◽  
Decision Feedback Equalizer ◽  
Free Space Optical ◽  
Space Optics ◽  
Link Distance ◽  
Mode Division Multiplexing ◽  
Simulation Results

AbstractIn mode division multiplexing (MDM) free space optical (FSO) communication system, the atmospheric turbulences such as fog, rain, and haze cause adverse effects on system performance. This paper investigates the mitigation of atmospheric turbulences of FSO using MDM and decision feedback equalizer (DFE) with minimum mean square error (MMSE) algorithm. The implementation of the MMSE algorithm is used to optimize both the feedforward and the feedback filter coefficients of DFE. The proposed system comprises three parallel 2.5Gbit/s channels using Hermite–Gaussian modes. A data rate of 7.5Gbit/s over 40 m, 800 m, 1400 m, and 2km under medium fog, rain, haze, and clear weather, respectively, has been achieved. In addition, it is noticed that the link distance is reduced while increasing the attenuation. The simulation results revealed that a DFE improves the performance MDM FSO system while maintaining high throughput and desired low bit error rate.

scholarly journals The Role and Challenges of Free-space Optical Systems

2014 ◽  
Vol 35 (4) ◽  
Author(s):  
Sushank Chaudhary ◽  
Angela Amphawan
Keyword(s):  
Free Space ◽  
Satellite Communications ◽  
Radio Networks ◽  
Optical Systems ◽  
Free Space Optics ◽  
Free Space Optical ◽  
Optical Carrier ◽  
High Data ◽  
Space Optics ◽  
Data Rates

AbstractComplementing wireless radio networks with free-space optics (FSO) achieves high data rates by modulating radio subcarriers over an optical carrier without expensive optical fiber cabling, enabling a pervasive platform for reaching underserved areas. In this paper, we review the main features of FSO for terrestrial and inter-satellite communications. Simulations of 1 Gbps data transmission through FSO links in both terrestrial and inter-satellite communications have been investigated to highlight potential atmospheric challenges in FSO.

scholarly journals Prediction of Received Optical Power for Switching Hybrid FSO/RF System

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1261
Author(s):  
Renát Haluška ◽  
Peter Šuľaj ◽  
Ľuboš Ovseník ◽  
Stanislav Marchevský ◽  
Ján Papaj ◽  
...  
Keyword(s):  
Optical Communication ◽  
Free Space ◽  
Communication Systems ◽  
Prediction Models ◽  
Optical Power ◽  
Free Space Optics ◽  
Communication Line ◽  
Atmospheric Transmission ◽  
Space Optics ◽  
Weather Information

This study deals with the problem of fiber-free optical communication systems—known as free space optics—using received signal strength identifier (RSSI) prediction analysis for hard switching of optical fiber-free link to base radio-frequency (RF) link and back. Adverse influences affecting the atmospheric transmission channel significantly impair optical communications, therefore attention was paid to the practical design, as well as to the implementation of the monitoring device that is used to record and process weather information along a transmission path. The article contains an analysis and methodology of the solution of the high availability of the optical link. Attention was paid to the technique of hard free space optics (FSO)/RF-switching with regard to the amount of received optical power detected and its relation to the quantities influencing the optical communication line. For this purpose, selected methods of machine learning were used, which serve to predict the received optical power. The process of analysis of prediction of received optical power is realized by regression models. The study presents the design of the optimal data input matrix model, which forms the basis for the training of the prediction models for estimating the received optical power.

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