Researches and the analysis of factors of the systems influencing quality with division according to radiation wavelength are given in article. Especially the communication quality in systems with wave division of channels is influenced by hindrances from Four Wave Mixing. In this regard the technique of definition of number of products of nonlinear effect of Four Wave Mixing getting to ranges of working channels, results of calculation of combinational products for the different number of channels in systems with division according to radiation wavelength is given. Power of a hindrance of Four Wave Mixing in systems with wave division of channels is calculated. Methods of reduction of influences of these nonlinear effects are considered. Conclusions and recommendations on ensuring quality of optical channels are provided in systems with wave division.
A mitigation of channel crosstalk effect in dispersion shifted fiber based on...IJECEIAES
In fiber optics the Four Wave Mixing (FWM) has the harmful effect of an optical transmission system that can severely limit Wavelength Division Multiplexing (WDM) and reduce the transmission aptness. This work preset the durability of the different modulation format was tested to FWM by using Dispersion Shifted Fiber (DSF). Moreover, the performance of the proposed system is surveyed by changing the fiber length and applying an information rate of 200 Gb/s. The experimental results show that the FWM capacity has decreased significantly by more than 14 dB when applying Return to Zero (RZ) modulation form. In addition, in terms of the propsed system performance in the first channel and with 700 km distance, it was observed that the lower Bit Error Rate (BER) in the normal RZ modulation is equal to 1.3×10 -13 . As well as it is noticeable when applied the Non Return to Zero (NRZ), the Modified Duobinary Return to Zero (MDRZ) and Gaussian modulation, the system performance will be quickly changed and getting worse, where the BERs increased to 1.3×10 consecutively at same channel and for the same parameters. -4 , 1.3×10 -6 and 1.3×10 -2
IMPLEMENTATION OF LINEAR DETECTION TECHNIQUES TO OVERCOME CHANNEL EFFECTS IN ...IJCI JOURNAL
Spatial diversity technique enables improvement in quality and reliability of wireless link. Antenna
diversity along with understanding effects of channel on transmitted signal and methods to overcome the
channel impairment plays an important role in wireless communication where sharing of channel occurs
between users. In this paper single input single output system (SISO) is compared with multiple input
multiple output system (MIMO) in terms of bit error rate performance. Bit error rate performance is also
evaluated for MIMO with least squares (LS) and Minimum mean square error (MMSE) linear detection.
Further analysis and simulation is done to understand the effect of channel imperfections on BER.
The telecommunication system includes the
transmission of a data bearing electromagnetic signal
through a physical medium that differentiates the
transmitter from the receiver. The relative effect of these
elements on reliable communication relies on upon the rate
of data transmission, on the craved loyalty upon gathering,
and on whether communication must happen in "real
time", for example as in phone conversations and video
teleconferencing. Moreover, microwaves are generally
utilized for point-to-point communications. Doubtlessly,
the telecom area has got a considerable measure of profit
from that communication technology additionally causes
some exception issues. Working with equipment that
works in this district obliges exceptional knowledge and
skills impressively unique in relation to those required for
traditional electronic equipment. Be that as it may, this
paper has examined for the issues of microwave
installation and demonstrates the accurate solutions for
the successful mobile communication world.
Today, we talk about the 5G NR communication technology and its characteristics.
The current communication technology is mainly divided into two types: wired communication and wireless communication. Wired communication uses wired media for conduction, such as copper wire, optical fiber, and so on.
Data transmission in wired media can reach a very high rate, and the current maximum experimental rate of a single fiber can reach 26Tbps. But the bottleneck of mobile communication lies in the wireless communication part. The current mainstream mobile communication standard is LTE, with a theoretical speed of 150Mbps, which is much lower than the wired transmission rate.
1) The document discusses reducing the effect of dispersion resulting from wavelength division multiplexing (WDM) in optical networks. Dispersion occurs when light pulses spread out as they travel through fiber optic cables, which degrades signal quality over long distances.
2) WDM is used to increase network capacity but also introduces longer fiber lengths, exacerbating dispersion issues. Different types of dispersion are discussed, including chromatic dispersion which causes slower wavelengths to interfere with faster wavelengths from adjacent pulses.
3) Chromatic dispersion is modeled and compensated for using Gaussian minimum-shift keying modulation and linear filters, which can be applied at the transmitter or receiver to counteract the spreading effect of the fiber on light pulses.
Application of multi antenna technologies in cellular mobile communicationsmarwaeng
This document discusses the application of multi-antenna technologies in cellular mobile communications. It introduces the general structure of multi-antenna systems and analyzes the characteristics of technologies like multiple input multiple output (MIMO) and adaptive antenna arrays. These technologies provide advantages over single antenna systems by improving channel capacity, combating multipath fading, and enhancing spectral efficiency. The document also prospects that multi-antenna technologies will be further applied in future cellular networks to meet increasing demands for bandwidth from more users and services.
This document discusses various types of transmission media and modes. It describes guided media like twisted pair cable, coaxial cable and fiber optic cable. It also describes unguided or wireless transmission media like radio waves, microwaves and infrared. For transmission modes, it explains serial vs parallel transmission and synchronous vs asynchronous transmission. Isochronous transmission with fixed bit transmission and equal gaps is also discussed.
This document provides an overview of basic WDM optical networks. It describes WDM as a multiplexing technique that allows multiple wavelengths to be transmitted over the same fiber. There are two main architectures: broadcast and select, which uses a simple star topology, and wavelength routed, which establishes light paths between nodes using the same wavelength. The document outlines the key components and working principles of each architecture, including their advantages and disadvantages. Wavelength routed networks allow for wavelength reuse but require efficient wavelength assignment to avoid bandwidth loss.
A mitigation of channel crosstalk effect in dispersion shifted fiber based on...IJECEIAES
In fiber optics the Four Wave Mixing (FWM) has the harmful effect of an optical transmission system that can severely limit Wavelength Division Multiplexing (WDM) and reduce the transmission aptness. This work preset the durability of the different modulation format was tested to FWM by using Dispersion Shifted Fiber (DSF). Moreover, the performance of the proposed system is surveyed by changing the fiber length and applying an information rate of 200 Gb/s. The experimental results show that the FWM capacity has decreased significantly by more than 14 dB when applying Return to Zero (RZ) modulation form. In addition, in terms of the propsed system performance in the first channel and with 700 km distance, it was observed that the lower Bit Error Rate (BER) in the normal RZ modulation is equal to 1.3×10 -13 . As well as it is noticeable when applied the Non Return to Zero (NRZ), the Modified Duobinary Return to Zero (MDRZ) and Gaussian modulation, the system performance will be quickly changed and getting worse, where the BERs increased to 1.3×10 consecutively at same channel and for the same parameters. -4 , 1.3×10 -6 and 1.3×10 -2
IMPLEMENTATION OF LINEAR DETECTION TECHNIQUES TO OVERCOME CHANNEL EFFECTS IN ...IJCI JOURNAL
Spatial diversity technique enables improvement in quality and reliability of wireless link. Antenna
diversity along with understanding effects of channel on transmitted signal and methods to overcome the
channel impairment plays an important role in wireless communication where sharing of channel occurs
between users. In this paper single input single output system (SISO) is compared with multiple input
multiple output system (MIMO) in terms of bit error rate performance. Bit error rate performance is also
evaluated for MIMO with least squares (LS) and Minimum mean square error (MMSE) linear detection.
Further analysis and simulation is done to understand the effect of channel imperfections on BER.
The telecommunication system includes the
transmission of a data bearing electromagnetic signal
through a physical medium that differentiates the
transmitter from the receiver. The relative effect of these
elements on reliable communication relies on upon the rate
of data transmission, on the craved loyalty upon gathering,
and on whether communication must happen in "real
time", for example as in phone conversations and video
teleconferencing. Moreover, microwaves are generally
utilized for point-to-point communications. Doubtlessly,
the telecom area has got a considerable measure of profit
from that communication technology additionally causes
some exception issues. Working with equipment that
works in this district obliges exceptional knowledge and
skills impressively unique in relation to those required for
traditional electronic equipment. Be that as it may, this
paper has examined for the issues of microwave
installation and demonstrates the accurate solutions for
the successful mobile communication world.
Today, we talk about the 5G NR communication technology and its characteristics.
The current communication technology is mainly divided into two types: wired communication and wireless communication. Wired communication uses wired media for conduction, such as copper wire, optical fiber, and so on.
Data transmission in wired media can reach a very high rate, and the current maximum experimental rate of a single fiber can reach 26Tbps. But the bottleneck of mobile communication lies in the wireless communication part. The current mainstream mobile communication standard is LTE, with a theoretical speed of 150Mbps, which is much lower than the wired transmission rate.
1) The document discusses reducing the effect of dispersion resulting from wavelength division multiplexing (WDM) in optical networks. Dispersion occurs when light pulses spread out as they travel through fiber optic cables, which degrades signal quality over long distances.
2) WDM is used to increase network capacity but also introduces longer fiber lengths, exacerbating dispersion issues. Different types of dispersion are discussed, including chromatic dispersion which causes slower wavelengths to interfere with faster wavelengths from adjacent pulses.
3) Chromatic dispersion is modeled and compensated for using Gaussian minimum-shift keying modulation and linear filters, which can be applied at the transmitter or receiver to counteract the spreading effect of the fiber on light pulses.
Application of multi antenna technologies in cellular mobile communicationsmarwaeng
This document discusses the application of multi-antenna technologies in cellular mobile communications. It introduces the general structure of multi-antenna systems and analyzes the characteristics of technologies like multiple input multiple output (MIMO) and adaptive antenna arrays. These technologies provide advantages over single antenna systems by improving channel capacity, combating multipath fading, and enhancing spectral efficiency. The document also prospects that multi-antenna technologies will be further applied in future cellular networks to meet increasing demands for bandwidth from more users and services.
This document discusses various types of transmission media and modes. It describes guided media like twisted pair cable, coaxial cable and fiber optic cable. It also describes unguided or wireless transmission media like radio waves, microwaves and infrared. For transmission modes, it explains serial vs parallel transmission and synchronous vs asynchronous transmission. Isochronous transmission with fixed bit transmission and equal gaps is also discussed.
This document provides an overview of basic WDM optical networks. It describes WDM as a multiplexing technique that allows multiple wavelengths to be transmitted over the same fiber. There are two main architectures: broadcast and select, which uses a simple star topology, and wavelength routed, which establishes light paths between nodes using the same wavelength. The document outlines the key components and working principles of each architecture, including their advantages and disadvantages. Wavelength routed networks allow for wavelength reuse but require efficient wavelength assignment to avoid bandwidth loss.
Mitigation of non-linear four-wave mixing phenomenon in a fully optical commu...TELKOMNIKA JOURNAL
This paper aims to point out the nonlinear phenomenon occurring in coarse/dense wavelength division multiplex (C/D-WDM) systems. This phenomenon has to betaken into account during the design of the optical network itself, as wavelengthsin the optical fiber are constantly densified. The paper points out the emergence of the non-linear four-wave mixing (FWM) phenomenonand how it relates to the dispersion in the optical fiber together with the transmit power. The output of the paper is a proposed design of the system that points to the improvement of the bit error rate (BER) with a suitable choice of dispersion and suitable transmission power.
This document discusses communication media and data transmission. It covers topics such as analog and digital signals, transmission basics, networking media like coaxial cable, twisted-pair cable, fiber-optic cable, and wireless transmission methods. It compares different media types and provides an overview of concepts like throughput, bandwidth, latency, attenuation, and noise. It also discusses topics like data modulation, transmission direction, multiplexing, and the physical layer standards for Ethernet networks.
This document discusses radio spectrum and wireless networks and protocols. It covers:
- The radio spectrum ranges from 30 Hertz to 300 GHz and is used for technologies like mobile phones, radio, TV and more.
- The spectrum is divided into bands and sub-bands to prevent interference between users.
- Shannon's theorem establishes the maximum possible transmission speed over a channel based on its bandwidth and signal-to-noise ratio.
- Licensed spectrum reserves certain frequencies that individual companies can pay to use exclusively, while unlicensed spectrum allows open use but is more vulnerable to interference.
This document describes a simulation of transmitting 20 channels of either 10 Gbps or 20 Gbps data over 80 km spans of conventional single mode fiber using wavelength division multiplexing in the L-band spectrum region. Both pre-compensation and post-compensation techniques for dispersion were considered. Post-compensation provided better performance with transmission distances of up to 720 km for a total throughput of 200 Gbps and 320 km for 400 Gbps, and lower bit error rates compared to pre-compensation. Non-linear effects and amplified spontaneous emission noise were also accounted for in the simulation.
Performance Analysis of OFDM in Combating Multipath FadingIOSR Journals
Mobile Communication system has been on high rampage for high data transmission over wireless
medium with various challenges caused by the transmission Channel. OFDM is been discovered in recent years
to deal with this problems because of its ability to elegantly cope with multipath interference. This paper
investigates the performance of different modulation schemes using M-ary Phase Shift Keying (M-PSK) and Mary
Quadrature Amplitude Modulation (M-QAM) in information transmission with OFDM technique over Ideal
channel AWGN and worst channel Rayleigh Fading channel in terms of Bits Error Rate (BER). Analysis was
made for different types of modulation schemes BPSK, QPSK, 4-QAM and 16-QAM gray coded bit mapping.
Also, a feasibility of OFDM been used to combat multipath fading was analyzed with comparison between a
single carrier technique and OFDM multicarrier technique. Variation between SNR results with respect to BER
is plotted to show the trade off differences between the modulation schemes with the result showing that OFDM
allows data transmission with minimal error over fading channel than a Single Carrier
This document discusses various types of transmission media, including guided media like twisted pair, coaxial cable, and optical fiber, as well as wireless transmission using microwave frequencies and antennas. It covers topics like the characteristics, bandwidth, and impairments of different media, as well as wireless propagation methods like ground wave, sky wave, and line of sight transmission and the effects of multipath interference and free space loss.
Integrated DWDM and MIMO-OFDM System for 4G High Capacity Mobile Communicatio...CSCJournals
This document describes a simulation of an integrated 64-channel dense wavelength division multiplexing (DWDM) system with multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) technology for high-capacity 4G mobile communication. The DWDM transmitter is designed to transmit baseband non-return-to-zero signals over fiber at 10 Gbps per channel for a total of 640 Gbps. After transmission over fiber with dispersion compensation, the signals are input to the MIMO-OFDM system. Space-time block coding is used to provide diversity in the MIMO-OFDM system. The performance is analyzed in terms of bit error rate with signal-to-noise ratio, achieving a desirable B
This document analyzes multipath fading profiles in multiple access system grids using orthogonal frequency division multiple access (OFDMA) systems. It discusses how OFDMA systems exploit multiuser diversity and frequency selectivity to achieve high spectral efficiencies but require feedback and are sensitive to delays. It proposes a non-iterative method for resource allocation that has lower complexity than previous methods and simulates higher data rates. It also analyzes popular feedback schemes and the impact of feedback delays on system throughput.
This document summarizes recent advances in wireless communication through the implementation of OFDM-MIMO systems. It discusses how OFDM can transmit multiple signals simultaneously using orthogonal subcarriers to improve data rates. MIMO uses multiple antennas at the transmitter and receiver to provide diversity gain and increase capacity. The combination of OFDM and MIMO (OFDM-MIMO) results in increased data rates and efficiency by overcoming problems like frequency selective fading. It then describes how OFDM-MIMO systems can transmit a single signal using transmit diversity and relay selection with decode-and-forward or amplify-and-forward protocols to further improve performance. Simulations show the OFDM-MIMO system achieves a lower bit error rate than
What does WDM (Wavelength Division Multiplexing )stand for?HYC Co., Ltd
This article will include these subject.
What does WDM stand for?
The basic structure of WDM system
Advantages of WDM technology
What does Mux and Demux stand for?
The difference between WDM and optical splitter
The indicators that affect the WDM devices
How to understand the O, E, S, C, L, U band
What does CWDM stand for vs. DWDM, FWDM, LWDM, MWDM?
HYC can provide customers with a one-stop optical network device and low-cost optical communication products, supplying a range of WDM products. HYC Co.,Ltd(HYC)is a national Hi-tech optoelectronics company engaged in R&D, manufacture and marketing of fiber optical products. Providing professional product and service for fiber connectivity,WDM, PLC splitter and high density datacom cabling. HYC products and solutions widely applied in 4G/5G, Data Center and Cloud Computing industry etc.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Transmission media is the physical medium used to transmit data between a sender and receiver. The two main types are guided and unguided media. Guided media uses physical pathways like cables to direct signals over shorter distances at high speeds securely. Common examples are twisted pair, coaxial, and fiber optic cables. Unguided media transmits electromagnetic waves without physical pathways, broadcasting signals through the air over longer distances less securely. Common examples are radio waves, microwaves, and infrared waves used in wireless technologies.
The document discusses recent advances in optical network technology, including components such as wavelength division multiplexing (WDM) systems, optical cross-connects, and optical switching technologies like MEMS. It outlines commercially available high-capacity optical systems providing terabits per second of capacity, as well as experimental WDM systems demonstrating multi-terabit capacities over long transmission distances. Emerging next generation optical networks are envisioned to be transparent, dynamic, and have switching at the wavelength level.
A carrier signal is a frequency that is modulated to carry analog or digital information for communication. Common examples are radio transmitters that modulate the frequency or amplitude of a carrier signal to transmit audio information. A carrier system provides multiple point-to-point communication channels using a technique like time-division multiplexing. Carrier service providers offer telephone and data communication between locations using networks like those built by Regional Bell Operating Companies. Modulation involves impressing voice, music, pictures or data onto a radio frequency carrier wave by varying its amplitude, frequency or phase. Common modulation types include amplitude modulation, frequency modulation, phase modulation, pulse code modulation and pulse duration modulation.
techInvestigations with mode division multiplexed transmissionelelijjournal
This article presents proposed topology for mode division multiplexed link with SPDML and VCSEL, modulate electrical signal of 820nm wavelength. Transmission performance has been investigated for numerous modes, bit rates (2.5 to 10Gbps), transmission lengths of MMF (1 to 100km) and attenuation factor in conjunction with parabolic operational mode. Results illustrated successful performance up to nine modes in mode-division multiplexed transmission. Performance is improved at low data rates, illustrated higher OSNR with lower BER,-5dB attenuation factor. Though, at higher bit rate and longer
transmission length received OSNR is unsteady. It further inferred that transmission with large number of multiplexed modes result in degraded performance, augmented with minimization of mode coupling losses.Mode division multiplexed multimode optical communication can be a viable option for supplementary capacity augment in the preexisting and future fiber optic communication links.
Iaetsd adaptive modulation in mimo ofdm system for4 gIaetsd Iaetsd
This paper proposes applying hybrid adaptation techniques in MIMO OFDM systems to improve spectral efficiency and reduce transmit power. It first analyzes the bit error rate of M-QAM modulation in OFDM systems with different numbers of subcarriers. Channel estimation is performed using MMSE, which estimates the channel with less error than LS. Feedback from channel estimation is then used with hybrid adaptation techniques. Simulation results show MMSE has lower MSE and symbol errors than LS estimation.
The peer-reviewed International Journal of Engineering Inventions (IJEI) is started with a mission to encourage contribution to research in Science and Technology. Encourage and motivate researchers in challenging areas of Sciences and Technology.
Single Mode Optical Fiber in Rof System Using DWDMIJERA Editor
Performance analysis was carried out to find the effect of crosstalk in a WDM system. Firstly, analysis of BER
was carried out without crosstalk. Then analysis of BER with crosstalk was done. Using equation for crosstalk,
number of channels was plotted using matlab. System parameters were optimized for a particular crosstalk.
Objective of the thesis work
Performance Analysis is carried out to find the effect of crosstalk due to optical cross connect in a DWDM
system considering a WDM based optical cross connect (OXC). An analysis is carried out to find the amount of
crosstalk due to OXC. The bit error rate performance degradation due to crosstalk is evaluated for OXC
parameter and number of wavelengths per fiber. The optimum parameters such as optimum number of channels
and hops are determined.
The Effect of PMD (Polarization Mode Dispersion) the Fibers of New and Old In...inventionjournals
This is a study conducted in a laboratory at the university as a simulation to see the effect of new fiber PMD for different distances. This is done to compare the performance of the digital system with optical fiber WDM. In this simulation are not included remission, chromatic dispersion and nonlinear effects. In this way all of the signal distortions caused only by different combinations of PDM. Polarization effects are very important in communications systems with optical fiber. Optical fiber that is used mainly during the simulation is a standard single mode fiber (SSMF).
Mitigation of non-linear four-wave mixing phenomenon in a fully optical commu...TELKOMNIKA JOURNAL
This paper aims to point out the nonlinear phenomenon occurring in coarse/dense wavelength division multiplex (C/D-WDM) systems. This phenomenon has to betaken into account during the design of the optical network itself, as wavelengthsin the optical fiber are constantly densified. The paper points out the emergence of the non-linear four-wave mixing (FWM) phenomenonand how it relates to the dispersion in the optical fiber together with the transmit power. The output of the paper is a proposed design of the system that points to the improvement of the bit error rate (BER) with a suitable choice of dispersion and suitable transmission power.
This document discusses communication media and data transmission. It covers topics such as analog and digital signals, transmission basics, networking media like coaxial cable, twisted-pair cable, fiber-optic cable, and wireless transmission methods. It compares different media types and provides an overview of concepts like throughput, bandwidth, latency, attenuation, and noise. It also discusses topics like data modulation, transmission direction, multiplexing, and the physical layer standards for Ethernet networks.
This document discusses radio spectrum and wireless networks and protocols. It covers:
- The radio spectrum ranges from 30 Hertz to 300 GHz and is used for technologies like mobile phones, radio, TV and more.
- The spectrum is divided into bands and sub-bands to prevent interference between users.
- Shannon's theorem establishes the maximum possible transmission speed over a channel based on its bandwidth and signal-to-noise ratio.
- Licensed spectrum reserves certain frequencies that individual companies can pay to use exclusively, while unlicensed spectrum allows open use but is more vulnerable to interference.
This document describes a simulation of transmitting 20 channels of either 10 Gbps or 20 Gbps data over 80 km spans of conventional single mode fiber using wavelength division multiplexing in the L-band spectrum region. Both pre-compensation and post-compensation techniques for dispersion were considered. Post-compensation provided better performance with transmission distances of up to 720 km for a total throughput of 200 Gbps and 320 km for 400 Gbps, and lower bit error rates compared to pre-compensation. Non-linear effects and amplified spontaneous emission noise were also accounted for in the simulation.
Performance Analysis of OFDM in Combating Multipath FadingIOSR Journals
Mobile Communication system has been on high rampage for high data transmission over wireless
medium with various challenges caused by the transmission Channel. OFDM is been discovered in recent years
to deal with this problems because of its ability to elegantly cope with multipath interference. This paper
investigates the performance of different modulation schemes using M-ary Phase Shift Keying (M-PSK) and Mary
Quadrature Amplitude Modulation (M-QAM) in information transmission with OFDM technique over Ideal
channel AWGN and worst channel Rayleigh Fading channel in terms of Bits Error Rate (BER). Analysis was
made for different types of modulation schemes BPSK, QPSK, 4-QAM and 16-QAM gray coded bit mapping.
Also, a feasibility of OFDM been used to combat multipath fading was analyzed with comparison between a
single carrier technique and OFDM multicarrier technique. Variation between SNR results with respect to BER
is plotted to show the trade off differences between the modulation schemes with the result showing that OFDM
allows data transmission with minimal error over fading channel than a Single Carrier
This document discusses various types of transmission media, including guided media like twisted pair, coaxial cable, and optical fiber, as well as wireless transmission using microwave frequencies and antennas. It covers topics like the characteristics, bandwidth, and impairments of different media, as well as wireless propagation methods like ground wave, sky wave, and line of sight transmission and the effects of multipath interference and free space loss.
Integrated DWDM and MIMO-OFDM System for 4G High Capacity Mobile Communicatio...CSCJournals
This document describes a simulation of an integrated 64-channel dense wavelength division multiplexing (DWDM) system with multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) technology for high-capacity 4G mobile communication. The DWDM transmitter is designed to transmit baseband non-return-to-zero signals over fiber at 10 Gbps per channel for a total of 640 Gbps. After transmission over fiber with dispersion compensation, the signals are input to the MIMO-OFDM system. Space-time block coding is used to provide diversity in the MIMO-OFDM system. The performance is analyzed in terms of bit error rate with signal-to-noise ratio, achieving a desirable B
This document analyzes multipath fading profiles in multiple access system grids using orthogonal frequency division multiple access (OFDMA) systems. It discusses how OFDMA systems exploit multiuser diversity and frequency selectivity to achieve high spectral efficiencies but require feedback and are sensitive to delays. It proposes a non-iterative method for resource allocation that has lower complexity than previous methods and simulates higher data rates. It also analyzes popular feedback schemes and the impact of feedback delays on system throughput.
This document summarizes recent advances in wireless communication through the implementation of OFDM-MIMO systems. It discusses how OFDM can transmit multiple signals simultaneously using orthogonal subcarriers to improve data rates. MIMO uses multiple antennas at the transmitter and receiver to provide diversity gain and increase capacity. The combination of OFDM and MIMO (OFDM-MIMO) results in increased data rates and efficiency by overcoming problems like frequency selective fading. It then describes how OFDM-MIMO systems can transmit a single signal using transmit diversity and relay selection with decode-and-forward or amplify-and-forward protocols to further improve performance. Simulations show the OFDM-MIMO system achieves a lower bit error rate than
What does WDM (Wavelength Division Multiplexing )stand for?HYC Co., Ltd
This article will include these subject.
What does WDM stand for?
The basic structure of WDM system
Advantages of WDM technology
What does Mux and Demux stand for?
The difference between WDM and optical splitter
The indicators that affect the WDM devices
How to understand the O, E, S, C, L, U band
What does CWDM stand for vs. DWDM, FWDM, LWDM, MWDM?
HYC can provide customers with a one-stop optical network device and low-cost optical communication products, supplying a range of WDM products. HYC Co.,Ltd(HYC)is a national Hi-tech optoelectronics company engaged in R&D, manufacture and marketing of fiber optical products. Providing professional product and service for fiber connectivity,WDM, PLC splitter and high density datacom cabling. HYC products and solutions widely applied in 4G/5G, Data Center and Cloud Computing industry etc.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Transmission media is the physical medium used to transmit data between a sender and receiver. The two main types are guided and unguided media. Guided media uses physical pathways like cables to direct signals over shorter distances at high speeds securely. Common examples are twisted pair, coaxial, and fiber optic cables. Unguided media transmits electromagnetic waves without physical pathways, broadcasting signals through the air over longer distances less securely. Common examples are radio waves, microwaves, and infrared waves used in wireless technologies.
The document discusses recent advances in optical network technology, including components such as wavelength division multiplexing (WDM) systems, optical cross-connects, and optical switching technologies like MEMS. It outlines commercially available high-capacity optical systems providing terabits per second of capacity, as well as experimental WDM systems demonstrating multi-terabit capacities over long transmission distances. Emerging next generation optical networks are envisioned to be transparent, dynamic, and have switching at the wavelength level.
A carrier signal is a frequency that is modulated to carry analog or digital information for communication. Common examples are radio transmitters that modulate the frequency or amplitude of a carrier signal to transmit audio information. A carrier system provides multiple point-to-point communication channels using a technique like time-division multiplexing. Carrier service providers offer telephone and data communication between locations using networks like those built by Regional Bell Operating Companies. Modulation involves impressing voice, music, pictures or data onto a radio frequency carrier wave by varying its amplitude, frequency or phase. Common modulation types include amplitude modulation, frequency modulation, phase modulation, pulse code modulation and pulse duration modulation.
techInvestigations with mode division multiplexed transmissionelelijjournal
This article presents proposed topology for mode division multiplexed link with SPDML and VCSEL, modulate electrical signal of 820nm wavelength. Transmission performance has been investigated for numerous modes, bit rates (2.5 to 10Gbps), transmission lengths of MMF (1 to 100km) and attenuation factor in conjunction with parabolic operational mode. Results illustrated successful performance up to nine modes in mode-division multiplexed transmission. Performance is improved at low data rates, illustrated higher OSNR with lower BER,-5dB attenuation factor. Though, at higher bit rate and longer
transmission length received OSNR is unsteady. It further inferred that transmission with large number of multiplexed modes result in degraded performance, augmented with minimization of mode coupling losses.Mode division multiplexed multimode optical communication can be a viable option for supplementary capacity augment in the preexisting and future fiber optic communication links.
Iaetsd adaptive modulation in mimo ofdm system for4 gIaetsd Iaetsd
This paper proposes applying hybrid adaptation techniques in MIMO OFDM systems to improve spectral efficiency and reduce transmit power. It first analyzes the bit error rate of M-QAM modulation in OFDM systems with different numbers of subcarriers. Channel estimation is performed using MMSE, which estimates the channel with less error than LS. Feedback from channel estimation is then used with hybrid adaptation techniques. Simulation results show MMSE has lower MSE and symbol errors than LS estimation.
The peer-reviewed International Journal of Engineering Inventions (IJEI) is started with a mission to encourage contribution to research in Science and Technology. Encourage and motivate researchers in challenging areas of Sciences and Technology.
Single Mode Optical Fiber in Rof System Using DWDMIJERA Editor
Performance analysis was carried out to find the effect of crosstalk in a WDM system. Firstly, analysis of BER
was carried out without crosstalk. Then analysis of BER with crosstalk was done. Using equation for crosstalk,
number of channels was plotted using matlab. System parameters were optimized for a particular crosstalk.
Objective of the thesis work
Performance Analysis is carried out to find the effect of crosstalk due to optical cross connect in a DWDM
system considering a WDM based optical cross connect (OXC). An analysis is carried out to find the amount of
crosstalk due to OXC. The bit error rate performance degradation due to crosstalk is evaluated for OXC
parameter and number of wavelengths per fiber. The optimum parameters such as optimum number of channels
and hops are determined.
The Effect of PMD (Polarization Mode Dispersion) the Fibers of New and Old In...inventionjournals
This is a study conducted in a laboratory at the university as a simulation to see the effect of new fiber PMD for different distances. This is done to compare the performance of the digital system with optical fiber WDM. In this simulation are not included remission, chromatic dispersion and nonlinear effects. In this way all of the signal distortions caused only by different combinations of PDM. Polarization effects are very important in communications systems with optical fiber. Optical fiber that is used mainly during the simulation is a standard single mode fiber (SSMF).
Dense wavelength division multiplexing....Arif Ahmed
The document discusses performance analysis of dense wavelength division multiplexing (DWDM) optical transmission systems. It begins with an introduction to DWDM, which allows transmission of up to 132 wavelengths over a single fiber. Section 2 provides an overview of optical fiber transmission and prior multiplexing techniques such as time division, frequency division, subcarrier, and coarse and dense wavelength division multiplexing. Section 3 indicates that the performance of DWDM will be analyzed using its application in NEMO, ANTARES, and KM3NeT underwater neutrino telescope experiments.
COMPARISON OF BER AND NUMBER OF ERRORS WITH DIFFERENT MODULATION TECHNIQUES I...Sukhvinder Singh Malik
This paper provides analysis of BER and Number of Errors for MIMO-OFDM wireless communication system by using different modulation techniques. Wireless designers constantly seek to improve the spectrum efficiency/capacity, coverage of wireless networks, and link reliability. So the performances of the wireless communication systems can be enhanced by using multiple transmit and receive antennas, which is generally referred to as the MIMO technique. Here analysis will be carried out for an OFDM wireless communication system using different modulation techniques and considering the effect and the wireless channel like AWGN, fading. Performance results will be evaluated numerically and graphically using the plots of BER versus SNR and plots of number of errors versus SNR.
Empirical analysis of polarization division multiplexing-dense wavelength di...IJECEIAES
This paper exemplifies dense wavelength division multiplexing combined with polarization division multiplexing with C-band frequency range-based single-mode fiber. In the proposed link, 32 independent channels with 16 individual wavelengths are multiplexed with two different angles of polarization. Each carrying 130 Gbps dual-polarization data with 200 GHz channel spacing claiming a net transmission rate of 4.16 Tbits/s with spectral efficiency of 69% with 20% side-mode-suppression-ratio (SMSR) and optical signal to noise ratio (OSNR) 40.7. The performance of the proposed techniques has been analyzed using optimized system parameters securing a minimum bit error rate (BER) 10-9 at a transmission distance up to 50 km.
RZ based dispersion compensation technique in dwdm system for broadband spectrumRamesh Patriotic
This document summarizes a study on using return-to-zero (RZ) pulse modulation and dispersion compensation techniques in dense wavelength division multiplexing (DWDM) systems. The study designs an 8-channel DWDM system using RZ pulse modulation at 2.5 Gbps over 100km of single-mode fiber. Dispersion compensation fiber is placed before the transmission fiber to reduce dispersion effects. Simulation results show that the RZ modulation technique offers improved eye diagrams, higher Q-factors, lower bit error rates, and broader transmitted spectra compared to non-return-to-zero modulation, indicating better performance for long-haul optical communication networks.
Iisrt 1-rz based dispersion compensation technique in dwdm system for broadba...IISRTJournals
This document summarizes a study on using return-to-zero (RZ) pulse generation and dispersion compensation techniques in dense wavelength division multiplexing (DWDM) systems to achieve broadband transmission over long distances. The study used simulation software to model an 8-channel DWDM system with and without dispersion compensation fibers. Results showed that using RZ pulses and dispersion compensation fibers improved key performance metrics like Q-factor and minimum bit error rate compared to non-return-to-zero pulses over a 100km single mode fiber link. Graphs and eye diagrams demonstrated lower jitter and better signal quality when using the RZ and dispersion compensation technique.
RZ based dispersion compensation technique in dwdm system for broadband spectrumIISRT
This document summarizes a study on using return-to-zero (RZ) pulse generation and dispersion compensation techniques in dense wavelength division multiplexing (DWDM) systems to achieve broadband transmission over long distances. The study used simulation software to model an 8-channel DWDM system with and without dispersion compensation fibers. Results showed that using RZ pulses and dispersion compensation fibers improved key performance metrics like Q-factor and minimum bit error rate compared to non-return-to-zero pulses without compensation. Analysis of eye diagrams and spectra also demonstrated lower distortion and broader transmission bandwidth when using the RZ and compensation technique.
- NOMA is a non-orthogonal multiple access technology that can improve spectral efficiency by allowing all users to use all time-frequency resources simultaneously through techniques like power domain multiplexing and successive interference cancellation. However, it increases complexity.
- Full duplex technology aims to allow simultaneous uplink and downlink transmission but faces challenges from strong self-interference. Solutions involve antenna separation and self-interference cancellation.
- OAM uses the orbital angular momentum of electromagnetic waves to create orthogonal channels at the same frequency but faces challenges in application to cellular networks from atmospheric effects.
- Machine learning can optimize 5G across all layers to dynamically improve spectrum efficiency based on conditions.
Design and Performance Study of MMDWDM Systemselelijjournal
The rising need for bandwidth created innumerable efforts from academic and industry group towards development of most efficient optical communication networks. In order to compete it numerous investigators have designed their own novel schemes. In this view the paper presents multiple modulation dense wavelength division multiplexed transmission designed links each with a total capacity of 640Gbps and with channel to channel to spacing of 100Ghz, employing multiple modulation schemes such as non return to zero rectangular, non return to zero raised cosine, return to zero rectangular, non return to zero raised cosine, return to zero soliton, return to zero Super Gaussian. The optical transmission performance characteristics like bit error rate, Q parameter at the output have been investigated by simulating different systems for a fixed transmission length of 260kilometers. Results show that transmission performance of DWDM system with non return to zero raised cosine scheme has been better with quality factor ranging from 16 to 23dB and bit error rate ranging from 10-11 to 10-40 for detected channels at selected transmission reach (260KM) and other schemes with good performance were RZ Super Guassian DWDM and RZ Soliton DWDM systems for the same transmission reach. The transmission parameter jitter have been also investigated for each system which depict that jitter effect is more severe for return to zero systems as compared to non return to zero DWDM systems. From the performance analysis for different optical links involving different modulation schemes it can be articulated that novel modulation scheme generally improves the transmission performance and must for modern optical communication systems operating at high bit rate and longer reach.
This document summarizes a research paper that investigates the effects of four-wave mixing using different modulation formats in optical communication systems. It finds that:
1) Four-wave mixing power decreases with increasing channel spacing and core effective fiber area, as greater spacing and area reduce signal interference.
2) Duobinary modulation exhibits lower four-wave mixing power than NRZ, with a 1dBm greater reduction when varying parameters.
3) Q-factor and BER improve with larger core effective area for both modulation formats, with duobinary showing more improvement due to its narrower spectrum and reduced phase matching.
This document analyzes wavelength assignment algorithms in WDM optical networks. It compares the random wavelength assignment algorithm to the first-fit algorithm in terms of blocking probability. It also compares networks with no wavelength conversion, full conversion, and sparse conversion. The blocking probability is found to be lowest with wavelength conversion and higher with no conversion. Within no conversion, first-fit performs better than random assignment. Sparse conversion has lower blocking than full conversion at high loads. The throughput is better than previous works, showing improved performance.
This document discusses wavelength assignment algorithms in WDM optical networks. It compares the random wavelength assignment algorithm to the first-fit algorithm in terms of blocking probability. Blocking probability is lower with the first-fit algorithm compared to the random algorithm. The document also examines the impact of wavelength conversion capabilities (no conversion, partial conversion, and full conversion) on blocking probability. Blocking probability is lowest when full wavelength conversion is possible. The first-fit algorithm performs better than random assignment even without wavelength conversion capabilities.
Techniques for Improving BER and SNR in MIMO Antenna for Optimum PerformanceIJMTST Journal
The use of multiple antennas for diversity, including MIMO (Multiple Input Multiple Output) is one of the most promising wireless technologies for broadband communication applications. This antenna system is a vital study in today’s wireless communication system especially when the signal propagates through some corrupted environments. In our paper new techniques of improving bit error ratio and signal to noise ratio are discussed. Inter symbol interference is a major limitation of wireless communications. It degrades the performance significantly if the delay spread is comparable or higher than the symbol duration. To remove ISI, equalization needs to be included at the receiver end. This paper discusses the merits of the MIMO system and the techniques used for improving BER performance and SNR. In MIMO wireless communication, an equalizer is used to recover a signal that suffers from Inter symbol Interference (ISI) and the BER characteristics is improved and a good SNR can be obtained. Different equalization techniques are discussed in this paper.
This document summarizes research on the effects of third-order dispersion (TOD) in long-haul optical fiber communication systems. The research used simulation software to model propagation of high-speed pulses through standard single-mode fiber (SSMF) and non-zero dispersion-shifted fiber (NZDSF) systems with dispersion compensation fiber (DCF). Results showed increased pulse broadening and oscillatory tails with higher bit rates due to TOD. NZDSF systems demonstrated lower distortion compared to SSMF. TOD effects were also dependent on transmission distance, duty cycle, and fiber types used. The outcomes provide insights useful for designing very high-speed, long-distance optical networks.
Performance Analysis of OFDM in Combating Multipath FadingIOSR Journals
Abstract: Mobile Communication system has been on high rampage for high data transmission over wireless medium with various challenges caused by the transmission Channel. OFDM is been discovered in recent years to deal with this problems because of its ability to elegantly cope with multipath interference. This paper investigates the performance of different modulation schemes using M-ary Phase Shift Keying (M-PSK) and M-ary Quadrature Amplitude Modulation (M-QAM) in information transmission with OFDM technique over Ideal channel AWGN and worst channel Rayleigh Fading channel in terms of Bits Error Rate (BER). Analysis was made for different types of modulation schemes BPSK, QPSK, 4-QAM and 16-QAM gray coded bit mapping. Also, a feasibility of OFDM been used to combat multipath fading was analyzed with comparison between a single carrier technique and OFDM multicarrier technique. Variation between SNR results with respect to BER is plotted to show the trade off differences between the modulation schemes with the result showing that OFDM allows data transmission with minimal error over fading channel than a Single Carrier. Keywords: OFDM, Single Carrier, AWGN, Rayleigh fading, BER, M-ary PSK, M-ary QAM
IRJET- Analysis of Nonlinearities in Fiber While Supporting 5GIRJET Journal
This document analyzes nonlinearities in optical fiber transmission while supporting 5G networks. It discusses how four wave mixing (FWM) introduces unwanted signals in fiber transmission. It models the transmission of signals using direct modulation, Mach-Zehnder modulation, and optical phase modulation over distances of 10-50 km. The signals are then amplified and analyzed. Simulation results show that FWM crosstalk increases with input power and transmission distance. Electrical spectrum analysis also reveals additional harmonic and intermodulation terms introduced by FWM.
This document provides an overview of dense wavelength division multiplexing (DWDM) technology. It discusses the history and components of a DWDM system, including transponders, multiplexers, fiber, amplifiers, and demultiplexers. It covers limiting factors such as linear and nonlinear effects that must be considered for DWDM systems. The document also discusses measurements and tests needed for DWDM system installation, optimization, and acceptance.
Channel Estimation Techniques in MIMO-OFDM LTE SystemsCauses and Effects of C...IJERA Editor
There is an increasing demand for high data transmission rates with the evolution of the very large scale integration (VLSI) technology. The multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems are used to fulfill these requirements because of their unique properties such as high spectral efficiency, high data rate and resistance towards multipath propagation. MIMO-OFDM systems are finding their applications in the modern wireless communication systems like IEEE 802.11n, 4G and LTE. They also offer reliable communication with the increased coverage area. The bottleneck to the MIMO-OFDM systems is the estimation of the channel state information (CSI). This can be estimated with the help of any one of the Training Based, Semiblind and Blind Channel estimation algorithms. This paper presents various channel estimation algorithms, optimization techniques and their effective utilization in MIMO-OFDM for modern wireless LTE systems.
Similar to About Quality of Optical Channels in Wavelength Division Multiplexing Systems of Optic Fibers (20)
Amazon products reviews classification based on machine learning, deep learni...TELKOMNIKA JOURNAL
In recent times, the trend of online shopping through e-commerce stores and websites has grown to a huge extent. Whenever a product is purchased on an e-commerce platform, people leave their reviews about the product. These reviews are very helpful for the store owners and the product’s manufacturers for the betterment of their work process as well as product quality. An automated system is proposed in this work that operates on two datasets D1 and D2 obtained from Amazon. After certain preprocessing steps, N-gram and word embedding-based features are extracted using term frequency-inverse document frequency (TF-IDF), bag of words (BoW) and global vectors (GloVe), and Word2vec, respectively. Four machine learning (ML) models support vector machines (SVM), logistic regression (RF), logistic regression (LR), multinomial Naïve Bayes (MNB), two deep learning (DL) models convolutional neural network (CNN), long-short term memory (LSTM), and standalone bidirectional encoder representations (BERT) are used to classify reviews as either positive or negative. The results obtained by the standard ML, DL models and BERT are evaluated using certain performance evaluation measures. BERT turns out to be the best-performing model in the case of D1 with an accuracy of 90% on features derived by word embedding models while the CNN provides the best accuracy of 97% upon word embedding features in the case of D2. The proposed model shows better overall performance on D2 as compared to D1.
Design, simulation, and analysis of microstrip patch antenna for wireless app...TELKOMNIKA JOURNAL
In this study, a microstrip patch antenna that works at 3.6 GHz was built and tested to see how well it works. In this work, Rogers RT/Duroid 5880 has been used as the substrate material, with a dielectric permittivity of 2.2 and a thickness of 0.3451 mm; it serves as the base for the examined antenna. The computer simulation technology (CST) studio suite is utilized to show the recommended antenna design. The goal of this study was to get a more extensive transmission capacity, a lower voltage standing wave ratio (VSWR), and a lower return loss, but the main goal was to get a higher gain, directivity, and efficiency. After simulation, the return loss, gain, directivity, bandwidth, and efficiency of the supplied antenna are found to be -17.626 dB, 9.671 dBi, 9.924 dBi, 0.2 GHz, and 97.45%, respectively. Besides, the recreation uncovered that the transfer speed side-lobe level at phi was much better than those of the earlier works, at -28.8 dB, respectively. Thus, it makes a solid contender for remote innovation and more robust communication.
Design and simulation an optimal enhanced PI controller for congestion avoida...TELKOMNIKA JOURNAL
This document describes using a snake optimization algorithm to tune the gains of an enhanced proportional-integral controller for congestion avoidance in a TCP/AQM system. The controller aims to maintain a stable and desired queue size without noise or transmission problems. A linearized model of the TCP/AQM system is presented. An enhanced PI controller combining nonlinear gain and original PI gains is proposed. The snake optimization algorithm is then used to tune the parameters of the enhanced PI controller to achieve optimal system performance and response. Simulation results are discussed showing the proposed controller provides a stable and robust behavior for congestion control.
Improving the detection of intrusion in vehicular ad-hoc networks with modifi...TELKOMNIKA JOURNAL
Vehicular ad-hoc networks (VANETs) are wireless-equipped vehicles that form networks along the road. The security of this network has been a major challenge. The identity-based cryptosystem (IBC) previously used to secure the networks suffers from membership authentication security features. This paper focuses on improving the detection of intruders in VANETs with a modified identity-based cryptosystem (MIBC). The MIBC is developed using a non-singular elliptic curve with Lagrange interpolation. The public key of vehicles and roadside units on the network are derived from number plates and location identification numbers, respectively. Pseudo-identities are used to mask the real identity of users to preserve their privacy. The membership authentication mechanism ensures that only valid and authenticated members of the network are allowed to join the network. The performance of the MIBC is evaluated using intrusion detection ratio (IDR) and computation time (CT) and then validated with the existing IBC. The result obtained shows that the MIBC recorded an IDR of 99.3% against 94.3% obtained for the existing identity-based cryptosystem (EIBC) for 140 unregistered vehicles attempting to intrude on the network. The MIBC shows lower CT values of 1.17 ms against 1.70 ms for EIBC. The MIBC can be used to improve the security of VANETs.
Conceptual model of internet banking adoption with perceived risk and trust f...TELKOMNIKA JOURNAL
Understanding the primary factors of internet banking (IB) acceptance is critical for both banks and users; nevertheless, our knowledge of the role of users’ perceived risk and trust in IB adoption is limited. As a result, we develop a conceptual model by incorporating perceived risk and trust into the technology acceptance model (TAM) theory toward the IB. The proper research emphasized that the most essential component in explaining IB adoption behavior is behavioral intention to use IB adoption. TAM is helpful for figuring out how elements that affect IB adoption are connected to one another. According to previous literature on IB and the use of such technology in Iraq, one has to choose a theoretical foundation that may justify the acceptance of IB from the customer’s perspective. The conceptual model was therefore constructed using the TAM as a foundation. Furthermore, perceived risk and trust were added to the TAM dimensions as external factors. The key objective of this work was to extend the TAM to construct a conceptual model for IB adoption and to get sufficient theoretical support from the existing literature for the essential elements and their relationships in order to unearth new insights about factors responsible for IB adoption.
Efficient combined fuzzy logic and LMS algorithm for smart antennaTELKOMNIKA JOURNAL
The smart antennas are broadly used in wireless communication. The least mean square (LMS) algorithm is a procedure that is concerned in controlling the smart antenna pattern to accommodate specified requirements such as steering the beam toward the desired signal, in addition to placing the deep nulls in the direction of unwanted signals. The conventional LMS (C-LMS) has some drawbacks like slow convergence speed besides high steady state fluctuation error. To overcome these shortcomings, the present paper adopts an adaptive fuzzy control step size least mean square (FC-LMS) algorithm to adjust its step size. Computer simulation outcomes illustrate that the given model has fast convergence rate as well as low mean square error steady state.
Design and implementation of a LoRa-based system for warning of forest fireTELKOMNIKA JOURNAL
This paper presents the design and implementation of a forest fire monitoring and warning system based on long range (LoRa) technology, a novel ultra-low power consumption and long-range wireless communication technology for remote sensing applications. The proposed system includes a wireless sensor network that records environmental parameters such as temperature, humidity, wind speed, and carbon dioxide (CO2) concentration in the air, as well as taking infrared photos.The data collected at each sensor node will be transmitted to the gateway via LoRa wireless transmission. Data will be collected, processed, and uploaded to a cloud database at the gateway. An Android smartphone application that allows anyone to easily view the recorded data has been developed. When a fire is detected, the system will sound a siren and send a warning message to the responsible personnel, instructing them to take appropriate action. Experiments in Tram Chim Park, Vietnam, have been conducted to verify and evaluate the operation of the system.
Wavelet-based sensing technique in cognitive radio networkTELKOMNIKA JOURNAL
Cognitive radio is a smart radio that can change its transmitter parameter based on interaction with the environment in which it operates. The demand for frequency spectrum is growing due to a big data issue as many Internet of Things (IoT) devices are in the network. Based on previous research, most frequency spectrum was used, but some spectrums were not used, called spectrum hole. Energy detection is one of the spectrum sensing methods that has been frequently used since it is easy to use and does not require license users to have any prior signal understanding. But this technique is incapable of detecting at low signal-to-noise ratio (SNR) levels. Therefore, the wavelet-based sensing is proposed to overcome this issue and detect spectrum holes. The main objective of this work is to evaluate the performance of wavelet-based sensing and compare it with the energy detection technique. The findings show that the percentage of detection in wavelet-based sensing is 83% higher than energy detection performance. This result indicates that the wavelet-based sensing has higher precision in detection and the interference towards primary user can be decreased.
A novel compact dual-band bandstop filter with enhanced rejection bandsTELKOMNIKA JOURNAL
In this paper, we present the design of a new wide dual-band bandstop filter (DBBSF) using nonuniform transmission lines. The method used to design this filter is to replace conventional uniform transmission lines with nonuniform lines governed by a truncated Fourier series. Based on how impedances are profiled in the proposed DBBSF structure, the fractional bandwidths of the two 10 dB-down rejection bands are widened to 39.72% and 52.63%, respectively, and the physical size has been reduced compared to that of the filter with the uniform transmission lines. The results of the electromagnetic (EM) simulation support the obtained analytical response and show an improved frequency behavior.
Deep learning approach to DDoS attack with imbalanced data at the application...TELKOMNIKA JOURNAL
A distributed denial of service (DDoS) attack is where one or more computers attack or target a server computer, by flooding internet traffic to the server. As a result, the server cannot be accessed by legitimate users. A result of this attack causes enormous losses for a company because it can reduce the level of user trust, and reduce the company’s reputation to lose customers due to downtime. One of the services at the application layer that can be accessed by users is a web-based lightweight directory access protocol (LDAP) service that can provide safe and easy services to access directory applications. We used a deep learning approach to detect DDoS attacks on the CICDDoS 2019 dataset on a complex computer network at the application layer to get fast and accurate results for dealing with unbalanced data. Based on the results obtained, it is observed that DDoS attack detection using a deep learning approach on imbalanced data performs better when implemented using synthetic minority oversampling technique (SMOTE) method for binary classes. On the other hand, the proposed deep learning approach performs better for detecting DDoS attacks in multiclass when implemented using the adaptive synthetic (ADASYN) method.
The appearance of uncertainties and disturbances often effects the characteristics of either linear or nonlinear systems. Plus, the stabilization process may be deteriorated thus incurring a catastrophic effect to the system performance. As such, this manuscript addresses the concept of matching condition for the systems that are suffering from miss-match uncertainties and exogeneous disturbances. The perturbation towards the system at hand is assumed to be known and unbounded. To reach this outcome, uncertainties and their classifications are reviewed thoroughly. The structural matching condition is proposed and tabulated in the proposition 1. Two types of mathematical expressions are presented to distinguish the system with matched uncertainty and the system with miss-matched uncertainty. Lastly, two-dimensional numerical expressions are provided to practice the proposed proposition. The outcome shows that matching condition has the ability to change the system to a design-friendly model for asymptotic stabilization.
Implementation of FinFET technology based low power 4×4 Wallace tree multipli...TELKOMNIKA JOURNAL
Many systems, including digital signal processors, finite impulse response (FIR) filters, application-specific integrated circuits, and microprocessors, use multipliers. The demand for low power multipliers is gradually rising day by day in the current technological trend. In this study, we describe a 4×4 Wallace multiplier based on a carry select adder (CSA) that uses less power and has a better power delay product than existing multipliers. HSPICE tool at 16 nm technology is used to simulate the results. In comparison to the traditional CSA-based multiplier, which has a power consumption of 1.7 µW and power delay product (PDP) of 57.3 fJ, the results demonstrate that the Wallace multiplier design employing CSA with first zero finding logic (FZF) logic has the lowest power consumption of 1.4 µW and PDP of 27.5 fJ.
Evaluation of the weighted-overlap add model with massive MIMO in a 5G systemTELKOMNIKA JOURNAL
The flaw in 5G orthogonal frequency division multiplexing (OFDM) becomes apparent in high-speed situations. Because the doppler effect causes frequency shifts, the orthogonality of OFDM subcarriers is broken, lowering both their bit error rate (BER) and throughput output. As part of this research, we use a novel design that combines massive multiple input multiple output (MIMO) and weighted overlap and add (WOLA) to improve the performance of 5G systems. To determine which design is superior, throughput and BER are calculated for both the proposed design and OFDM. The results of the improved system show a massive improvement in performance ver the conventional system and significant improvements with massive MIMO, including the best throughput and BER. When compared to conventional systems, the improved system has a throughput that is around 22% higher and the best performance in terms of BER, but it still has around 25% less error than OFDM.
Reflector antenna design in different frequencies using frequency selective s...TELKOMNIKA JOURNAL
In this study, it is aimed to obtain two different asymmetric radiation patterns obtained from antennas in the shape of the cross-section of a parabolic reflector (fan blade type antennas) and antennas with cosecant-square radiation characteristics at two different frequencies from a single antenna. For this purpose, firstly, a fan blade type antenna design will be made, and then the reflective surface of this antenna will be completed to the shape of the reflective surface of the antenna with the cosecant-square radiation characteristic with the frequency selective surface designed to provide the characteristics suitable for the purpose. The frequency selective surface designed and it provides the perfect transmission as possible at 4 GHz operating frequency, while it will act as a band-quenching filter for electromagnetic waves at 5 GHz operating frequency and will be a reflective surface. Thanks to this frequency selective surface to be used as a reflective surface in the antenna, a fan blade type radiation characteristic at 4 GHz operating frequency will be obtained, while a cosecant-square radiation characteristic at 5 GHz operating frequency will be obtained.
Reagentless iron detection in water based on unclad fiber optical sensorTELKOMNIKA JOURNAL
A simple and low-cost fiber based optical sensor for iron detection is demonstrated in this paper. The sensor head consist of an unclad optical fiber with the unclad length of 1 cm and it has a straight structure. Results obtained shows a linear relationship between the output light intensity and iron concentration, illustrating the functionality of this iron optical sensor. Based on the experimental results, the sensitivity and linearity are achieved at 0.0328/ppm and 0.9824 respectively at the wavelength of 690 nm. With the same wavelength, other performance parameters are also studied. Resolution and limit of detection (LOD) are found to be 0.3049 ppm and 0.0755 ppm correspondingly. This iron sensor is advantageous in that it does not require any reagent for detection, enabling it to be simpler and cost-effective in the implementation of the iron sensing.
Impact of CuS counter electrode calcination temperature on quantum dot sensit...TELKOMNIKA JOURNAL
In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime.
In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime.
A progressive learning for structural tolerance online sequential extreme lea...TELKOMNIKA JOURNAL
This article discusses the progressive learning for structural tolerance online sequential extreme learning machine (PSTOS-ELM). PSTOS-ELM can save robust accuracy while updating the new data and the new class data on the online training situation. The robustness accuracy arises from using the householder block exact QR decomposition recursive least squares (HBQRD-RLS) of the PSTOS-ELM. This method is suitable for applications that have data streaming and often have new class data. Our experiment compares the PSTOS-ELM accuracy and accuracy robustness while data is updating with the batch-extreme learning machine (ELM) and structural tolerance online sequential extreme learning machine (STOS-ELM) that both must retrain the data in a new class data case. The experimental results show that PSTOS-ELM has accuracy and robustness comparable to ELM and STOS-ELM while also can update new class data immediately.
Electroencephalography-based brain-computer interface using neural networksTELKOMNIKA JOURNAL
This study aimed to develop a brain-computer interface that can control an electric wheelchair using electroencephalography (EEG) signals. First, we used the Mind Wave Mobile 2 device to capture raw EEG signals from the surface of the scalp. The signals were transformed into the frequency domain using fast Fourier transform (FFT) and filtered to monitor changes in attention and relaxation. Next, we performed time and frequency domain analyses to identify features for five eye gestures: opened, closed, blink per second, double blink, and lookup. The base state was the opened-eyes gesture, and we compared the features of the remaining four action gestures to the base state to identify potential gestures. We then built a multilayer neural network to classify these features into five signals that control the wheelchair’s movement. Finally, we designed an experimental wheelchair system to test the effectiveness of the proposed approach. The results demonstrate that the EEG classification was highly accurate and computationally efficient. Moreover, the average performance of the brain-controlled wheelchair system was over 75% across different individuals, which suggests the feasibility of this approach.
Adaptive segmentation algorithm based on level set model in medical imagingTELKOMNIKA JOURNAL
For image segmentation, level set models are frequently employed. It offer best solution to overcome the main limitations of deformable parametric models. However, the challenge when applying those models in medical images stills deal with removing blurs in image edges which directly affects the edge indicator function, leads to not adaptively segmenting images and causes a wrong analysis of pathologies wich prevents to conclude a correct diagnosis. To overcome such issues, an effective process is suggested by simultaneously modelling and solving systems’ two-dimensional partial differential equations (PDE). The first PDE equation allows restoration using Euler’s equation similar to an anisotropic smoothing based on a regularized Perona and Malik filter that eliminates noise while preserving edge information in accordance with detected contours in the second equation that segments the image based on the first equation solutions. This approach allows developing a new algorithm which overcome the studied model drawbacks. Results of the proposed method give clear segments that can be applied to any application. Experiments on many medical images in particular blurry images with high information losses, demonstrate that the developed approach produces superior segmentation results in terms of quantity and quality compared to other models already presented in previeous works.
Automatic channel selection using shuffled frog leaping algorithm for EEG bas...TELKOMNIKA JOURNAL
Drug addiction is a complex neurobiological disorder that necessitates comprehensive treatment of both the body and mind. It is categorized as a brain disorder due to its impact on the brain. Various methods such as electroencephalography (EEG), functional magnetic resonance imaging (FMRI), and magnetoencephalography (MEG) can capture brain activities and structures. EEG signals provide valuable insights into neurological disorders, including drug addiction. Accurate classification of drug addiction from EEG signals relies on appropriate features and channel selection. Choosing the right EEG channels is essential to reduce computational costs and mitigate the risk of overfitting associated with using all available channels. To address the challenge of optimal channel selection in addiction detection from EEG signals, this work employs the shuffled frog leaping algorithm (SFLA). SFLA facilitates the selection of appropriate channels, leading to improved accuracy. Wavelet features extracted from the selected input channel signals are then analyzed using various machine learning classifiers to detect addiction. Experimental results indicate that after selecting features from the appropriate channels, classification accuracy significantly increased across all classifiers. Particularly, the multi-layer perceptron (MLP) classifier combined with SFLA demonstrated a remarkable accuracy improvement of 15.78% while reducing time complexity.
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024Sinan KOZAK
Sinan from the Delivery Hero mobile infrastructure engineering team shares a deep dive into performance acceleration with Gradle build cache optimizations. Sinan shares their journey into solving complex build-cache problems that affect Gradle builds. By understanding the challenges and solutions found in our journey, we aim to demonstrate the possibilities for faster builds. The case study reveals how overlapping outputs and cache misconfigurations led to significant increases in build times, especially as the project scaled up with numerous modules using Paparazzi tests. The journey from diagnosing to defeating cache issues offers invaluable lessons on maintaining cache integrity without sacrificing functionality.
Batteries -Introduction – Types of Batteries – discharging and charging of battery - characteristics of battery –battery rating- various tests on battery- – Primary battery: silver button cell- Secondary battery :Ni-Cd battery-modern battery: lithium ion battery-maintenance of batteries-choices of batteries for electric vehicle applications.
Fuel Cells: Introduction- importance and classification of fuel cells - description, principle, components, applications of fuel cells: H2-O2 fuel cell, alkaline fuel cell, molten carbonate fuel cell and direct methanol fuel cells.
Software Engineering and Project Management - Introduction, Modeling Concepts...Prakhyath Rai
Introduction, Modeling Concepts and Class Modeling: What is Object orientation? What is OO development? OO Themes; Evidence for usefulness of OO development; OO modeling history. Modeling
as Design technique: Modeling, abstraction, The Three models. Class Modeling: Object and Class Concept, Link and associations concepts, Generalization and Inheritance, A sample class model, Navigation of class models, and UML diagrams
Building the Analysis Models: Requirement Analysis, Analysis Model Approaches, Data modeling Concepts, Object Oriented Analysis, Scenario-Based Modeling, Flow-Oriented Modeling, class Based Modeling, Creating a Behavioral Model.
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECTjpsjournal1
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
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fiber, but also has a set of advantages, such as light expansibility and reliability of operation,
especially to them should note a possibility of direct connection of various services and granting
a wide strip.
At introduction of WDM the quality of signaling is influenced by specific factors which
are demanded by researches. Research of influence of major factors as four wave mixing
(FWM) and also hindrances from the neighboring canals and the restriction of total power of a
light signal introduced in optical fiber will allow to solve problems of realization and introduction
of the WDM systems and will promote ensuring the required quality of transfer of optical signals.
The aforesaid shows relevance of a subject of this article. The purpose of article is the research
of quality of signaling in the perspective fiber-optical systems of transfer with division according
to wavelength.
2. Research Method
The following problems are for this purpose solved:
a. The analysis and a research of the major factors influencing quality of signaling in WDM;
b. The analysis of the WDM parameters providing high-quality signaling;
c. A research of methods of improvement of quality of signaling in WDM.
The factors influencing quality of transfer of WDM are given in Figure 1. Factors
between axes the power and time belong to the fiber-optical systems of transfer (FOST) with
temporary division and wave division of channels. On an axis of power such parameters as the
power of the laser, loss in fiber and the losses brought by components are postponed.
Figure 1. The factors influencing quality of WDM
Along other axis the parameters connected with time are postponed. It is polarizing
mode dispersion of fiber, chromatic dispersion and also instability of a signal and speed of
transfer. On crossing of axes there are new parameters demanding account: depth of
modulation of the laser, nonlinearity of fiber, relative intensity of noise and coefficient of bit
mistakes.
The axis wavelength belongs only to the WDM system and much more complicates
representation of key parameters. Along an axis of lengths of waves the following parameters
are postponed: stability of a range, spectral range of the EDFA amplifier, central wavelength
and width of bandwidth. On crossing of parameters of time and wavelength settle down:
deviation of frequency of the laser, chromatic dispersion, stability of optical frequency and phase
noise. Joint influence of wavelength and power is shown in such phenomena as: the
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strengthened spontaneous radiation of ASE, strengthening of EDFA, cross hindrances, four
wave mixture and the compelled combinational dispersion (Raman). And, at last, the compelled
Brillouin-Mandelstam's dispersion is defined by all set of variables [3].
At WDM design all these factors have to be considered in a due measure. The wrong
design often doesn't allow to realize potential opportunities of the used expensive equipment [4].
We will consider the above-mentioned major factors influencing quality of signaling in WDM.
At WDM realization first of all it is necessary to provide the maximum coefficient of
strengthening of EDFA at the maximum relation signal/noise. It takes place when using lasers
with the wavelength on which the minimum absorption of optical radiation is provided. In this
regard recently the increasing distribution is found by lasers with the wavelength of 980
nanometers which in comparison with lasers on 1480 nanometers provide smaller absorption at
bigger coefficient of strengthening of EDFA.
Other factor defining the choice of the laser are its stability and a spectral characteristic
of radiation which define degree of their negative impact on EDFA as the last add optical noise
(ASE) to the strengthened signal in all strip of transmission frequencies, but not to an entrance
of each certain canal. It, leads to redistribution of levels of signals in various channels and to
their mutual influence that predetermines need of measurement of level of noise on all
communication line supporting many EDFA as each amplifier increases not only the level of a
signal, but also level of noise. As a result noise extends on all lengths of waves whereas the
signal passes only across canals with certain lengths of waves. As the level of strengthening of
each amplifier changes depending on wavelength, there is a danger that noise of extra band
signals will be strengthened stronger, than a useful signal. Though the difference at one stage
of strengthening can be insignificant, several stages of strengthening can already have
significant effect on the relation signal/noise.
When multiplexing and DE multiplexing signals of bandwidth of channels have to
correspond precisely to the chosen lengths of waves not to create cross hindrances, and extra
band suppression on each channel has to be rather high for an exception of influence of the
neighboring canals and side petals. Besides, they have to provide only the admissible shift of
the central wavelength of the leading laser of any channel without essential weakening of a
signal.
Optical amplifiers, as a rule, of EDFA, provide economic operation of WDM due to
essential strengthening of all channels irrespective of schemes of modulation and the used
protocols. It means that the modulated optical signal can be transmitted to very long distances
without the need for intermediate recovery and repeated formation of the transmitted data.
However during creation of network, especially when certain canals support several amplifiers,
it is necessary to consider dependence of strengthening of EDFA on wavelength, moreover, as
indicators of noise of separate EDFA exert a great influence on integrity of an optical signal,
they will define the necessary number of amplifiers and as a result the maximum extent of
connection. The linear optical amplifiers used in the WDM systems according to the
characteristics have to correspond to the recommendations of ITU-T G.661, G.662, G.663 [5-7].
For WDM functioning, characteristics of the most optical fiber (OF) are more important.
When studying WDM considerably bigger attention has to be paid to chromatic dispersion.
WDM usually use small, carefully controlled part of optical range for reduction of influence of
Four Wave Mixing (FWM). Also in WDM working with use of high speeds, the special complexity
is represented by a question of polarizing mode of dispersion (PMD) at which the speed of
distribution of a light wave depends on her condition of polarization. Now there are no known
ways of elimination of influence of this type of dispersion. PMD has to be measured and
reduced, by means of the choice of components.
With the advent of WDM, levels of signals have increased is hundredfold. At association
of an exit of the laser transmitter with the optical amplifier it was necessary to generate levels of
signals about +20 dBm to offset the losses caused by use of the passive WDM elements. These
high levels of signals have aggravated many reasons leading to deterioration, anyway leading to
degradation of a signal and characteristics in general [8].
Therefore it is necessary to reduce total power, entered into fiber. Maximum power of
each optical channel Pmax (in dBm) depends on the full optical capacity given from a
transponder exit to an input of fiber Рfull (optical power (in dBm) and numbers of the multiplexed
lengths of waves of n
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Pmax.= Рfull.∙ 10lgn. (1)
Considering that Pfull. it is limited to either a class of safe level of radiation of the laser,
or admissible level of total nonlinear distortions in a core of fiber and makes size from 17 to 30
dBm for different producers of the equipment of WDM, it is possible approximately to estimate
as this power counting on the channel for different number of channels as shown in Table 1
changes.
From this table it is visible that at a large number of channels falling of power can make
(against initial level -2 channels) 21 dB, and it can lead to problems with ensuring the necessary
level of coefficient of mistakes in the optical channel. The only way of fight against it is increase
in effective cross-sectional area of fiber [9].
Table 1. Level of the maximum power in each WDM channel at her uniform distribution
Number of channels, n 2 4 8 16 32 64 128 256
Pfull = 17 dBm 14 11 8 5 2 -1 -4 -7
Pfull = 30 dBm 27 24 21 18 15 12 9 6
In WDM owing to dependence of index of refraction of OF on electric field there are
nonlinear effects. The main destabilizing factor is the nonlinear effect as FWM. In a result of
parametrical strengthening when the intensity of a laser signal reaches critical level and when
OF plays a passive role of the environment of distribution, there are four wave mixture,
generation of harmonicas in which several optical waves interact thanks to a nonlinear response
of the electrons of external covers excited by them.
FWM leads to emergence of the new disturbing harmonicas, part of them gets to
working canals of system. From compliance of the disturbing harmonicas with frequencies of the
working channel cross hindrances appear. These disturbing factors worsen quality of signaling
and can put out of action the WDM system completely. FWM essence (from positions of
quantum mechanics) is that if there is an interaction of four linearly polarized along an axis x
optical waves ,432,1 ,,, ffff to frequencies that destruction of photons of one frequency and the
birth of photons of other frequencies at conservation of energy can be observed and an impulse.
It can occur according to two schemes:
a. transmission of energy of three photons to the fourth, generated at a frequency
;3214 ffff
b. transmission of energy of two photons two new, generated at frequencies
.2143 ffff
Formally these schemes can be consolidated in one: ,3214 ffff having generalized it
for a case of interaction of three linearly polarized any waves kji fff ,, presented in the
form [9]
.kjiijk ffff (2)
FWM can arise even in single-channel systems between signals of the working channel and
components of the strengthened spontaneous issue of optical amplifiers and also between the
main and side mode.
3. Results and Analysis
The analysis has shown that, in WDM influence of FWM is especially destructive since
the FWM level is sensitive to system characteristics: to increase in power in the channel; to
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increase in number of channels; to reduction of a step between channels that causes need of a
research of their influence on the level of hindrances and a ratio signal/noise.
However in works the accurate technique of determination of power of hindrances isn't
given in spectral channel WDM that doesn't allow to calculate precisely the optical signal/noise
ratio (OSNR) in the channel and to compare this size to existing rules. The analysis has shown
that, in WDM influence of FWM is especially destructive since the FWM level is sensitive to
system characteristics: to increase in power in the channel; to increase in number of channels;
to reduction of a step between channels that causes need of a research of their influence on the
level of hindrances and a ratio signal/noise.
In this regard the technique of definition of number of the products getting to the canal is
of interest. In Figure 2 the arrangement of the optical bearing channels in WDM range at the
restrictions stated above is shown, let the influencing channels are i, j, to. Signals in channels i,
j, k create the nonlinear hindrance of the third order of the first sort getting to channel x at the
expense of FWM. Frequency of this hindrance can be or a three-frequency product of a type of
fx=fi+fj-fk, or two-frequency a type of fx=2 fj-fk. Here i, j, k can accept any values within the total
number of channels N
Figure 2. An arrangement of the optical bearing channels in WDM range
The canal in N-channel system to which three-frequency products get has number:
kjix (3)
when performing conditions
jkij
xkji
kji
Nkji
;
;0,,,
;.,1
(4)
For a two-frequency product the channel y to which these products get has number
kjy 2 (5)
on condition of
0,,,
;
;
ykji
jk
kji
(6)
If optical signals get to channels i, j, k at the same time, then the frequency of channel x which
gets a three-frequency product is equal:
)( kjFff ix
(7)
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Follows that fx can is both on a working range of WDM, and out of it, i.e. as a result of FWM the
range in OF considerably extends. Total number of products of nonlinearity is defined from a
ratio [8]:
2/)1(2
NNN (8)
For example, for eight-channel system (N=8) N =224, а при N=16 number of products
N =1920. In Figure 3 results of calculation of number of products are given in channels at N=8
(a, b) and N=16 (c, d). Three-frequency products are presented in Figures 3a and 3c, and two-
frequency-in Figure 3b and 3d. From the Figure 3 it is possible to draw the following
conclusions:
a. the maximum quantity of three-frequency products takes place in the central channels;
b. at increase in number of channels in system, the quantity of the influencing products
sharply increases in the channel. For example, at N=the 8th maximum number of three-
frequency products in the central channel N=24, and at N=the 16th Nc3 value=140. i.e.
increase in capacity of system twice leads to sharp increase in number of the influencing
products;
c. the quantity of two-frequency products in each channel are much less than number three-
frequency (for example, at N=1610 eighth channel number of three-frequency products-
140, and two-frequency-7).
Figure 3. Results of calculation of number of products in channels at N=8 (a,b) and N = 16 (c,d)
We will consider calculation of power of hindrances because of FWM on an entrance of
the linear amplifier of flight of WDM. According to the recommendation of ITU-T G.692, width of
a range of the channel is accepted equal 0,1 nanometers (12,5 GHz). We will determine
hindrance power because of FWM on an entrance of the amplifier with a length of flight of L.
Calculation of power of each product of nonlinearity is executed in [8-9]. The general power of
products of nonlinearity in the channel x is defined from expression:
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)( 2,,23,, ckjckjix NPNPP , (9)
where cc NN 33 , -quantity of three-frequency and two-frequency products of nonlinearity,
respectively; kjiP ,, and kjP ,,2 -capacities of each type of a product;
5,12/)(2 ГГцB , (10)
a coefficient of channel spectrum spreading under the high-speed transmission. kjiP ,, We will
write down power in a look:
)exp(3
,,,, LPP inkjikji , (11)
where inP -power in one channel at the WDM transmitter booster exit; kji ,, -the efficiency of
FWM which is function of a mismatch of phases between signals of the interacting waves.
When determining power of nonlinear hindrances in the channel for section it is
necessary to consider that this power collects from the amplifier to the amplifier. We will assume
that all flights in section of identical length and amplifiers don't create nonlinear hindrances, then
on an entrance of each amplifier there will be products of FWM which amplify the amplifier.
Besides, the output power of a signal will create FWM in each flight. Therefore hindrance power
because of FWM on an entrance of the WDM receiver can be determined on a formula:
xnn
N
i
xnnpxc NPPP 1
. (12)
If lengths of flights aren't identical, then generally
N
i
xnnpx PP
1
2
. (13)
We will define security of a signal from a hindrance because of FWM from a ratio:
dB
P
P
OSNR
xc
ch
,lg10 (14)
Results of calculation. We will calculate capacities of the products arising because of
FWM for the section WDM at a transfer speed 10gbit/s for different types of the fibers,
proceeding from data given in Table 2.
Table 2. Different Types of the Fibers
Type of fiber SMF DSF
, dB/km 0,22 0,22
effA , sm2 7
105 7
105
1111X , ergsm3 15
109,8 15
1093,8
kmnmpsDs , 18 3,5
kmnmpsddDs , 0,093 0,080
n 1,467 1,469
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Table 2. Different Types of the Fibers
Type of fiber SMF DSF
kmL, 80
km, 1550
Full optical strip, GHz 2000
It has turned out that at the exit of the section consisting of eight identical flights, the
power of nonlinear hindrances in the noisiest 8th channel was 408,24 pW for SMF and
129,9 nW-for DSF fiber. Calculation of OSNR was made from the assumption that signal power
in one channel at the exit of the amplifier of 1 MW and the line turns on eight amplifiers. At the
same time the relation the signal/hindrance makes 48 dBm for SMF fiber, 15,8 dBm-DSF.
On the basis of dependence between the relations a signal/hindrance and probability of
a mistake in the channel for WDM, we conclude that probability mistakes less than 10-12 that
satisfies to the recommendations of ITU-T only for SMF fiber. Increase in a step between optical
bearing and chromatic dispersion reduce FWM process, due to destruction of phase ratios
between the interacting waves. For reduction influence of nonlinear effects it is also possible to
use an uneven step or the increased step between channels.
4. Conclusion
By results of the conducted researches it is possible to draw the following conclusions:
a. WDM-the developing, branched technology difficult and multiple parameter system which
the set of the internal and external destabilizing factors influencing quality of signaling
influence;
b. The main destabilizing factors influencing quality of signaling in WDM are: influence of
FWM, a hindrance in the neighboring canals and restrictions of the total power of a light
signal entered into optical fiber, a relation deviation signal/noise;
c. Identification of the reasons worsening quality of the transmitted signals and finding of
ways of their compensation decide by means of use of mathematical methods. In work
methods of a research of characteristics of system from her parameters are used
generally;
d. In WDM influence of FWM is especially destructive since the FWM level is sensitive to
system characteristics.
e. in 200 GHz decreasing step systems, the FWM level sharply decreases to compare with
100 GHz decreasing step systems, absolute value of chromatic dispersion is redacted also
Recommendations about ensuring the required quality of transfer of optical signals to WDM:
a. It is necessary to optimize the transferred power of an optical signal taking into account the
correct arrangement of amplifiers.
b. To turn on attention, on rational distribution of inter channel intervals, the number of lengths
of waves and their stabilization;
c. The systems using G.653 fiber have the biggest nonlinear effect of FWM, but the
arrangement of frequency of the working channel near zero dispersion can lead to
significantly short length of the line (tens of kilometers). Therefore use of G.653 fiber in the
DWDM systems isn't recommended [10].
d. In standard G.652 FWM fibers very much it is less. However use of G.652 [11] fibers in the
DWDM systems isn't expedient because big dispersion reduces length of the regeneration
site.
e. Influence of FWM is less in G.655 fibers, especially in fibers with a big effective area.
f. Dispersion, on the one hand, has to be rather small, so that it didn't cause broadening of
impulses. On the other hand, for suppression of the cross hindrances arising because of
nonlinear effects, dispersion has to be rather big therefore as dispersion, optimum for
WDM, it is necessary to recognize fibers with the nonzero displaced dispersion of G.655
[12];
g. For neutralization of effect of FWM it is possible to use uneven intervals between WDM
channels;
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h. The considered method of calculation of nonlinear hindrances because of FWM can be
used both for design of the main WDM, and for the analysis of results of their testing.
References
[1] ITU-T Rec. G.694.1-Spectral grids for WDM applications: DWDM frequency grid (6.02).
[2] ITU-T G.692-Optical interfaces for multichannel systems with optical amplifiers (10.98). Corrigendum
1,2(1.00,6.02).
[3] Андрэ Жирар. Руководство по технологии и тестированию систем WDM.–М.: EXFO, 2001./ Пер.
с англ. под ред. А.М. Бородниковского, Р.Р. Убайдуллаева, А.В. Шмалько/ Общая редакция
А.В. Шмалько. 214 с.
[4] Сайт компании "Контур-М" /www.konturm.ru/
[5] ITU-T G.661-Definition and test methods for the relevant generic parameters of optical fiber
amplifiers (10.98).
[6] ITU-T G.662-Generic characteristics of optical fiber amplifier devices and sub-systems (10.98).
[7] ITU-T G.663-Application related aspects of optical fiber amplifier devices and sub-systems (4.00).
[8] Фриман Р. Волоконно оптические системы связи”, Издательство “Техносфера 2003.,350 с
[9] Волоконно-оптическая техника: Современное состояние и перспективы. - 2-е изд., перераб. и
доп. / Сб. статей под ред. Дмитриева С.А. и Слепова Н.Н.-М.: ООО "Волоконно-оптическая
техника", 2005. - 576 с.
[10] ITU-T G.653-Characteristics of a Dispersion-Shifted Single-Mode Optical Fiber Cable (10.00).
[11] ITU-T G.652-Characteristics of a Single-Mode Optical Fiber Cable (10.00, 2003).
[12] ITU-T G.655-Characteristics of a Non-Zero Dispersion Shifted Single-Mode Optical Fiber Cable
(10.00).