scholarly journals Assessment of fog and rain induced-attenuation on terrestrial FSO links

Author(s):  
M. O. Ajewole

 Launching into the next generation of wireless communication network (5G network) requires secure high data rate, high speed and huge bandwidth links. With the tremendous increase in broadband users, the existing communication systems such as radio frequency (RF) and microwave links cannot meet up with the challenges due to their link interference and low bandwidth. A current technology that promises such requirements and more is Free Space Optical (FSO) communication. The FSO basically involves the transmission of signal-modulated optical radiation from a transmitter to a receiver through the atmosphere or outer space. It is designed to complement the traditional fibre optical communication links. However, location-variant atmospheric channel degrades the quality and performance of an FSO system under severe atmospheric conditions. This paper attempts to assess both fog- and rain-induced attenuation on the performance of FSO link in a terrestrial terrain using measured visibility and rain rate data at Akure, Nigeria. 5-year (2012-2016) archived visibility data and measured rain rate data of 1-minute integration time obtained from Nigerian Meteorological Agency (NIMET) and the Department of Physics, Federal University of Technology, Akure respectively, were used to compute the fog- and rain-induced specific attenuations using Kruse and Carboneur models. The performance of the FSO system was analyzed through link margin by using the parameters of a commercial optical transceiver, Terescope 5000. Findings from this work will be useful for FSO system design in the area.

Author(s):  
Ajewole , M. O. ◽  
Owolawi , P. A. ◽  
Adetunji , R. M.

Notice of Retraction-----------------------------------------------------------------------After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of APTIKOM's Publication Principles.We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.The presenting author of this paper has the option to appeal this decision by contacting ij.aptikom@gmail.com.-----------------------------------------------------------------------  Launching into the next generation of wireless communication network (5G network) requires secure high data rate, high speed and huge bandwidth links. With the tremendous increase in broadband users, the existing communication systems such as radio frequency (RF) and microwave links cannot meet up with the challenges due to their link interference and low bandwidth. A current technology that promises such requirements and more is Free Space Optical (FSO) communication. The FSO basically involves the transmission of signal-modulated optical radiation from a transmitter to a receiver through the atmosphere or outer space. It is designed to complement the traditional fibre optical communication links. However, location-variant atmospheric channel degrades the quality and performance of an FSO system under severe atmospheric conditions. This paper attempts to assess both fog- and rain-induced attenuation on the performance of FSO link in a terrestrial terrain using measured visibility and rain rate data at Akure, Nigeria. 5-year (2012-2016) archived visibility data and measured rain rate data of 1-minute integration time obtained from Nigerian Meteorological Agency (NIMET) and the Department of Physics, Federal University of Technology, Akure respectively, were used to compute the fog- and rain-induced specific attenuations using Kruse and Carboneur models. The performance of the FSO system was analyzed through link margin by using the parameters of a commercial optical transceiver, Terescope 5000. Findings from this work will be useful for FSO system design in the area.


Author(s):  
Joseph Sunday Ojo ◽  
Owolawi P. A. ◽  
Ajewole M. O. ◽  
Adetunji R. M.

 Reliable broadband communication requires secure high data rate and bandwidth links. With the observed increase in broadband users, known communication systems such as RF and microwave links cannot promise such requirements due to link interference and low bandwidth. A current communication system that promises such requirements and more is Free Space Optical (FSO) communication. This system basically involves the transmission of signal-modulated optical radiation from a transmitter to a receiver through the atmosphere or outer space. However, location-variant atmospheric channel degrades the performance of an FSO system under severe atmospheric conditions, thus necessitating local atmospheric attenuation studies. This paper presents the characterization of both fog- and rain-induced attenuation and the performance of an FSO system in a terrestrial terrain at Akure, Nigeria. One-year archived visibility data and in-situ measured 1-minute integration time rain rate data obtained from Nigerian Meteorological Agency (NIMET) and the Department of Physics, Federal University of Technology, Akure were used to compute the fog- and rain-induced specific attenuations using Kruse model and Carboneur model respectively. The performance of the FSO system is analyzed through link margin by using the parameters of a commercial optical transceiver, Terescope 5000.


2020 ◽  
Vol 4 (3) ◽  
pp. 125-134
Author(s):  
Ajewole M. O ◽  
Owolawi P. A ◽  
Ojo J. S ◽  
Adetunji R. M.

Reliable broadband communication requires secure high data rate and bandwidth links. With the observedincrease in broadband users, known communication systems such as RF and microwave links cannot promise suchrequirements due to link interference and low bandwidth. A current communication system that promises suchrequirements and more is Free Space Optical (FSO) communication. This system basically involves the transmissionof signal-modulated optical radiation from a transmitter to a receiver through the atmosphere or outer space. However,location-variant atmospheric channel degrades the performance of an FSO system under severe atmosphericconditions, thus necessitating local atmospheric attenuation studies.This paper presents the characterization of both fog- and rain-induced attenuation and the performance ofan FSO system in a terrestrial terrain at Akure, Nigeria. One-year archived visibility data and in-situ measured 1-minute integration time rain rate data obtained from Nigerian Meteorological Agency (NIMET) and the Departmentof Physics, Federal University of Technology, Akure were used to compute the fog- and rain-induced specificattenuations using Kruse model and Carboneur model respectively. The performance of the FSO system is analyzedthrough link margin by using the parameters of a commercial optical transceiver, Terescope 5000.


Author(s):  
M. O. Ajewole ◽  
P. A. Owolawi ◽  
J. S. Ojo ◽  
R. M. Adetunji

Launching into the next generation of wireless communication network (5G network) requires secure highdata rate, high speed and huge bandwidth links. With the tremendous increase in broadband users, the existingcommunication systems such as radio frequency (RF) and microwave links cannot meet up with the challenges due totheir link interference and low bandwidth. A current technology that promises such requirements and more is FreeSpace Optical (FSO) communication. The FSO basically involves the transmission of signal-modulated opticalradiation from a transmitter to a receiver through the atmosphere or outer space. It is designed to complement thetraditional fibre optical communication links. However, location-variant atmospheric channel degrades the qualityand performance of an FSO system under severe atmospheric conditions. This paper attempts to assess both fog- andrain-induced attenuation on the performance of FSO link in a terrestrial terrain using measured visibility and rainrate data at Akure, Nigeria. 5-year (2012-2016) archived visibility data and measured rain rate data of 1-minuteintegration time obtained from Nigerian Meteorological Agency (NIMET) and the Department of Physics, FederalUniversity of Technology, Akure respectively, were used to compute the fog- and rain-induced specific attenuationsusing Kruse and Carboneur models. The performance of the FSO system was analyzed through link margin by usingthe parameters of a commercial optical transceiver, Terescope 5000. Findings from this work will be useful for FSOsystem design in the area.


2020 ◽  
Vol 12 (11) ◽  
pp. 179
Author(s):  
Magdalena Garlinska ◽  
Agnieszka Pregowska ◽  
Karol Masztalerz ◽  
Magdalena Osial

Fast communication is of high importance. Recently, increased data demand and crowded radio frequency spectrum have become crucial issues. Free-Space Optical Communication (FSOC) has diametrically changed the way people exchange information. As an alternative to wire communication systems, it allows efficient voice, video, and data transmission using a medium like air. Due to its large bandwidth, FSOC can be used in various applications and has therefore become an important part of our everyday life. The main advantages of FSOC are a high speed, cost savings, compact structures, low power, energy efficiency, a maximal transfer capacity, and applicability. The rapid development of the high-speed connection technology allows one to reduce the repair downtime and gives the ability to quickly establish a backup network in an emergency. Unfortunately, FSOC is susceptible to disruption due to atmospheric conditions or direct sunlight. Here, we briefly discuss Free-Space Optical Communication from mirrors and optical telegraphs to modern wireless systems and outline the future development directions of optical communication.


2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohammad Yawar Wani ◽  
Hitesh Pathak ◽  
Karamjit Kaur ◽  
Anil Kumar

AbstractFree space optical communication systems (FSO’s) have surfaced as admired means of communication in the past few years. High speed of operation, low bandwidth requirements and system reliability are the major factors responsible for their wide range of applications. These communication systems use air as a medium of transmission. Since there is no component like fiber or cable, but air is only medium, the variations in atmospheric conditions play a vital role in performance of these networks. The reason behind is that the conditions like presence of humidity, haze, snowfall, rain, dust or smoke changes the attenuation coefficient of medium. The raised attenuation levels results in increased losses and need to be carefully monitored. The present work analyzes the influence of rain on the performance of FSO network in terms of quality of transmission. The paper discusses the impact of rainfall on attenuation coefficient of air. Then impact of this attenuation on network transmission is presented in terms of BER and Q-factor. In order to demonstrate the impact, BER and Q-value is calculated for 10 Gbps FSO link for clear weather and rainfall conditions.


2014 ◽  
Vol 513-517 ◽  
pp. 3987-3991
Author(s):  
Naveed Ur Rehman ◽  
Lei Zhang ◽  
Muhammad Zahid Hammad ◽  
Emmanuel Anania Mwangosi

The rapid growth within the field of digital communication during the recent years expanded the need for high-speed data transmission to support a wide range of services such as: video, data and voice in wireless communication systems, etc. Orthogonal frequency division multiplexing (OFDM) and a multicarrier modulation scheme are employed to achieve the high data rates. Since OFDM is very much sensitive to carrier frequency offsets, which cause the Inter-carrier Interference (ICI) leads to mitigation of this ICI is necessary. The objectives of this paper are to, proposed an efficient ICI self-cancellation scheme to mitigate the effect of ICI on OFDM systems. For this purpose, a redundant data is transmitted onto adjacent sub-carriers such that the ICI between adjacent sub-carriers cancels out at the receiver side. One data symbol is modulated into a group of adjacent sub carriers with a group of weighting coefficients. At the receiver side, the received signals are linearly combined on these sub carriers with proposed coefficients. The residual ICI contained in the received signals can then be further reduced. This study provides significant carrier-to-interference power ratio (CIR) improvement, which has been studied theoretically and supported by simulations. Since no channel equalization is required to reduce ICI, so the proposed scheme doesnt increase the system complexity.


T-Comm ◽  
2020 ◽  
Vol 14 (10) ◽  
pp. 45-52
Author(s):  
Edgar M. Dmitriyev ◽  
◽  
Eugeny V. Rogozhnikov ◽  
Andrey K. Movchan ◽  
Semyon M. Mukhamadiev ◽  
...  

In the presented article, the results of the research of the spreading spectrum technology are given and its use in communication systems based on the data transmission over power lines is considered. One of the currently existing problems of data transmission systems over power lines is the absence of a compromise solution in ensuring the required data transmission rate and communication range. Ready-made solutions existing on the market provide either high data transmission rates over short distances or a communication long-range with rates not exceeding several tens of kilobits per second. The purpose of the article is to research the application of spread spectrum technology in data transmission systems over power lines. In the course of the experiment, it was found that the joint use of OFDM technology and the spread spectrum technology makes it possible to form a solution that provides communication over power lines over a distance of tens of meters with a data transmission rate of at least 5 Mbps. This article compares the TP-Link 500 Mbps modem for broadband high-speed data transmission, and the NWEPLC-1-G3M modem for narrowband low-speed data transmission. The results of modeling a communication system with different lengths and types of spreading sequences for BPSK and QPSK modulations are presented. An assessment of the interference protection was carried out. The results of an experimental research of the spectrum spreading technology on a model of a data transmission system over power lines in terms of range and transmission rate in comparison with existing devices on the market are presented. The results obtained can be used in the design of communication systems over power lines.


Author(s):  
Islam Md Rafiqul ◽  
Md Moktarul Alam ◽  
Ali Kodhim Lwas ◽  
Sarah Yasmin Mohamad

Attenuation due to rain is an important constraint in microwave radio link design especially at frequencies above 10 GHz. It restricts the path length of radio communication systems and limits the use of higher frequencies for line-of-sight microwave links and satellite communications. In order to predict the attenuation due to rain accurately rainfall intensity is required with 1-minute integration time. Rainfall is a meteorological phenomenon with complex structure due to its variability in space, duration and occurrence frequency, particularly in tropical and equatorial regions. Since, the statistical distribution of rain attenuation is obtained from the rain rate distribution for the region considered, it should be noted that the accuracy of the rain rate measurement affects the accuracy of the attenuation estimation. This paper presents rain intensity with 1-minute integration time measured for 6 years in Malaysia, it’s distribution, comparison with other prediction models and impact on high frequency microwave links.


Author(s):  
Yazan Alkhlefat ◽  
Sevia Mahdaliza Idrus Sutan Nameh ◽  
Farabi M. Iqbal

Current and future wireless communication systems are designed to achieve the user’s demands such as high data rate and high speed with low latency and simultaneously to save bandwidth and spectrum. In 5G and 6G networks, a high speed of transmitting and switching is required for internet of things (IoT) applications with higher capacity. To achieve these requirements a semiconductor optical amplifier (SOA) is considered as a wavelength converter to transmit a signal with an orthogonal frequency division multiplexing with subcarrier power modulation (OFDM-SPM). It exploits the subcarrier’s power in conventional OFDM block in order to send additional bits beside the normally transmitted bits. In this paper, we optimized the SOA’s parameters to have efficient wavelength conversion process. These parameters are included the injection current (IC) of SOA, power of pump and probe signals. A 7 Gbps OFDM-SPM signal with a millimeter waves (MMW) carrier of 80 GHz is considered for signal switching. The simulation results investigated and analyzed the performance of the designed system in terms of error vector magnitude (EVM), bit error rate (BER) and optical signal-to-noise ratio (OSNR). The optimum value of IC is 0.6 A while probe power is 9.45 and 8.9 dBm for pump power. The simulation is executed by virtual photonic integrated (VPI) software.


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