Optical multiplexing is the key function of a WDM network and reliable method for data transport networks. WDM networks configured as rings/mesh along with Optical Add-Drop Multiplexers supports added flexibility, simplicity and augment the spectral efficiency. Further enhancement achieved with
Reconfigurable OADM architectures, growing briskly along with automatic network management, let the transport network to acclimatize with dynamically varying environment and flexibly respond to the transport network changes. It permits single or many wavelengths to be added and/or dropped from a
transport fiber without optical-to-electrical-to-optical domain translation. Presently ROADM technology has revolutionized optical networking and an inseparable part of modern optical communication offering huge bandwidth for data transport at minimum expense. In this view the article presents comprehensive study for numerous generations of ROADM and their architecture and persistent development.
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.
This document compares LTE networks using frequency division duplexing (FDD) versus time division duplexing (TDD). FDD uses separate frequencies for downlink and uplink, while TDD uses timesharing of a single frequency between downlink and uplink. TDD can operate with unpaired spectrum and dynamically allocate bandwidth between downlink and uplink. FDD generally provides better support for symmetric traffic like voice calls but requires paired spectrum. The document presents simulation results showing the coverage area and throughput of FDD and TDD LTE networks. It concludes that the preferred duplexing method depends on the intended use and characteristics of the network and traffic.
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.
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 reviews the OFDM-IDMA technique and its implementations. It begins with introductions to OFDM and OFDM-IDMA. OFDM-IDMA uses interleaving instead of spreading sequences to distinguish users, avoiding bandwidth expansion without coding gain. The document then summarizes various implementations of OFDM-IDMA using discrete wavelet transform, MIMO systems, and implementations on FPGA. It also discusses implementations using finite Radon transform and discrete wavelet transform. Finally, it proposes future work on implementing OFDM-IDMA using Radon transform and performing comparative analysis of wavelet, FFT, and Radon-based OFDM-IDMA systems over AWGN and Rayleigh fading channels.
This document discusses techniques to enhance channel capacity in OFDM systems. It begins with an introduction to OFDM and discusses its advantages such as reduced inter-symbol interference and high spectral efficiency. Then it discusses two main techniques for enhancing channel capacity: singular value decomposition (SVD) and water filling algorithms. SVD decomposes the channel matrix to decouple the spatial channels, allowing transmission power to be distributed optimally. Water filling algorithms such as iterative water filling further optimize power allocation to increase capacity. The document provides an overview of how these techniques can enhance the capacity of OFDM wireless communication systems.
Wavelet Packet based Multicarrier Modulation for Cognitive UWB SystemsCSCJournals
Orthogonal frequency division multiplexing (OFDM) is a multi-carrier modulation (MCM) scheme where the sub carriers are orthogonal waves. The main advantages of OFDM are robustness against multi-path fading, frequency selective fading, narrowband interference, and efficient use of spectrum. Recently it is proved that MCM system optimization can be achieved by applying wavelet bases instead of conventional fourier bases. Wavelet packet based MCM (WPMCM) systems have overall the same capabilities as OFDM systems with some improved features. In this research the literature and analytic schemes of WPMCM system is addressed, a wavelet packet based cognitive ultra wideband (UWB) transceiver is proposed, and performance analysis of WPMCM in different wireless multipath channels is investigated. Simulation results show a significant enhancement in terms of BER, spectral efficiency and side-lobes suppression comparing to conventional OFDM.
Performance Evaluation of PAPR Reduction with SER and BER by Modified Clippin...ijcsse
This paper work focuses on performance analysis of PAPR reduction of orthogonal frequency division multiplexing (OFDM) using amplitude clipping & filtering based design. Now a days one of the most proficient multi-carrier transmission techniques widely used today is orthogonal frequency division multiplexing (OFDM) which has been implemented by the next generation wireless communication technology: Long Term Evolution (LTE). Extra robustness to multipath fading and impulse noise is provided OFDM. It eliminates inter symbol interference (ISI) & inter carrier interference (ICI) with certain procedure. Therefore peak to average power ratio (PAPR) is the basic problem with OFDM. However in this paper we proposed a reduction procedure of the PAPR by using clipping and filtering. Here we use a composed high pass , low pass & Chevyshev band pass filter II after amplitude clipping to reduce the PAPR. The performance of the system in terms of bit error rate (BER) and symbol error rate (SER) is also investigated as a new filter based clipping method is proposed. Our proposed clipping method with and composed high pass the Chevyshev bandpass filter II in PAPR performance of the system with a little compromise of BER & SER showing the significant improvement in Quadrature Amplitude Modulation (QAM).
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.
This document compares LTE networks using frequency division duplexing (FDD) versus time division duplexing (TDD). FDD uses separate frequencies for downlink and uplink, while TDD uses timesharing of a single frequency between downlink and uplink. TDD can operate with unpaired spectrum and dynamically allocate bandwidth between downlink and uplink. FDD generally provides better support for symmetric traffic like voice calls but requires paired spectrum. The document presents simulation results showing the coverage area and throughput of FDD and TDD LTE networks. It concludes that the preferred duplexing method depends on the intended use and characteristics of the network and traffic.
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.
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 reviews the OFDM-IDMA technique and its implementations. It begins with introductions to OFDM and OFDM-IDMA. OFDM-IDMA uses interleaving instead of spreading sequences to distinguish users, avoiding bandwidth expansion without coding gain. The document then summarizes various implementations of OFDM-IDMA using discrete wavelet transform, MIMO systems, and implementations on FPGA. It also discusses implementations using finite Radon transform and discrete wavelet transform. Finally, it proposes future work on implementing OFDM-IDMA using Radon transform and performing comparative analysis of wavelet, FFT, and Radon-based OFDM-IDMA systems over AWGN and Rayleigh fading channels.
This document discusses techniques to enhance channel capacity in OFDM systems. It begins with an introduction to OFDM and discusses its advantages such as reduced inter-symbol interference and high spectral efficiency. Then it discusses two main techniques for enhancing channel capacity: singular value decomposition (SVD) and water filling algorithms. SVD decomposes the channel matrix to decouple the spatial channels, allowing transmission power to be distributed optimally. Water filling algorithms such as iterative water filling further optimize power allocation to increase capacity. The document provides an overview of how these techniques can enhance the capacity of OFDM wireless communication systems.
Wavelet Packet based Multicarrier Modulation for Cognitive UWB SystemsCSCJournals
Orthogonal frequency division multiplexing (OFDM) is a multi-carrier modulation (MCM) scheme where the sub carriers are orthogonal waves. The main advantages of OFDM are robustness against multi-path fading, frequency selective fading, narrowband interference, and efficient use of spectrum. Recently it is proved that MCM system optimization can be achieved by applying wavelet bases instead of conventional fourier bases. Wavelet packet based MCM (WPMCM) systems have overall the same capabilities as OFDM systems with some improved features. In this research the literature and analytic schemes of WPMCM system is addressed, a wavelet packet based cognitive ultra wideband (UWB) transceiver is proposed, and performance analysis of WPMCM in different wireless multipath channels is investigated. Simulation results show a significant enhancement in terms of BER, spectral efficiency and side-lobes suppression comparing to conventional OFDM.
Performance Evaluation of PAPR Reduction with SER and BER by Modified Clippin...ijcsse
This paper work focuses on performance analysis of PAPR reduction of orthogonal frequency division multiplexing (OFDM) using amplitude clipping & filtering based design. Now a days one of the most proficient multi-carrier transmission techniques widely used today is orthogonal frequency division multiplexing (OFDM) which has been implemented by the next generation wireless communication technology: Long Term Evolution (LTE). Extra robustness to multipath fading and impulse noise is provided OFDM. It eliminates inter symbol interference (ISI) & inter carrier interference (ICI) with certain procedure. Therefore peak to average power ratio (PAPR) is the basic problem with OFDM. However in this paper we proposed a reduction procedure of the PAPR by using clipping and filtering. Here we use a composed high pass , low pass & Chevyshev band pass filter II after amplitude clipping to reduce the PAPR. The performance of the system in terms of bit error rate (BER) and symbol error rate (SER) is also investigated as a new filter based clipping method is proposed. Our proposed clipping method with and composed high pass the Chevyshev bandpass filter II in PAPR performance of the system with a little compromise of BER & SER showing the significant improvement in Quadrature Amplitude Modulation (QAM).
This paper analyzes the performance of three routing protocols (AODV, DSDV, OLSR) for mobile WiMAX networks using the random direction mobility model in NS3 simulator. The protocols are evaluated based on routing overhead, packet delivery ratio, throughput, end-to-end delay, and packet loss. The results found that OLSR protocol outperformed AODV and DSDV, with lower routing overhead and higher packet delivery ratio, demonstrating improved efficiency for WiMAX networks.
Optical space division multiplexing uses multiple cores or modes in optical fibers to increase transmission capacity. A history of the technology was provided, noting the progression from single mode fibers to coherent detection and polarization multiplexing. Limits with single mode fibers were discussed, along with ways that multi-core and multi-mode fibers can overcome capacity constraints through spatial multiplexing across fiber cores and modes. Recent demonstrations showed record capacities of 57.6 Tb/s over multi-mode fiber and 24 Tb/s over hollow-core fiber. Integration challenges with spatial division multiplexing were also outlined.
An optical add-drop multiplexer (OADM) is a device used in WDM systems that allows routing of different fiber channels into or out of a single mode fiber. It consists of an optical demultiplexer, multiplexer, and method to reconfigure signal paths. The demultiplexer separates wavelengths on input fiber to ports. OADMs can add or drop single or multiple wavelengths from a fully multiplexed signal, allowing intermediate sites on a fiber link to access the connection. Additional wavelengths can be added or dropped by successive OADMs as needed in the network.
1. The document discusses adopting layer 2 Ethernet switching over DWDM networks to address bandwidth demands of new media-rich applications.
2. Traditional SONET/SDH networks are overloaded and complex to scale, while Ethernet over SONET wastes bandwidth.
3. Layer 2 Ethernet switching over DWDM networks can eliminate unnecessary protocol conversions, reduce costs, simplify operations, and provide optimal scalability to meet rising bandwidth demands more cost-effectively.
DESIGN OF A COMPACT CIRCULAR MICROSTRIP PATCH ANTENNA FOR WLAN APPLICATIONS pijans
This paper presents the design of a compact circular microstrip patch antenna for WLAN applications which covers the band 5.15 to 5.825 GHz. The antenna is designed using 1.4mm thick FR-4 (lossy)substrate with relative permittivity 4.4 and a microstrip line feed is used. The radius of the circular patch is chosen as 7.62mm. To reduce the size and enhance the performance of the proposed antenna, a circular slot is loaded on circular patch and a square slot is etched on the ground plane of dimension 30mm×30mm. Design of the antenna is carried out using CST Microsoft Studio Sonimulation Software. The proposed antenna resonates at 5.5 GHz with a wider bandwidth of 702 MHz and it provides low return loss of -31.58 dB, good gain of 3.23 dB and directivity of 4.28 dBi and high efficiency of around 79% against the resonance frequency. The geometry of the proposed circular antenna with reduced size and its various performance parameters such as return loss, bandwidth, VSWR, gain, directivity, efficiency and radiation pattern plots are presented and discussed.
1. The document discusses Filter Bank Multi-Carrier (FBMC) as an alternative to OFDM that provides better spectral properties and allows for MIMO techniques to be applied more easily.
2. It presents a spreading technique for FBMC symbols using Hadamard matrices that cancels imaginary interference and allows restoration of complex orthogonality within transmission blocks. This reduces complexity compared to other spreading approaches.
3. The performance of FBMC and OFDM is analyzed in double-selective channels at high speeds, and it is shown that FBMC can achieve a higher signal-to-interference ratio than OFDM in such conditions. Bit error rate is also derived for various modulation schemes.
Adaptive Resource Allocation in MIMO-OFDM Communication Systemijsrd.com
Multiple Input and Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) system have the potential to achieve very high capacity depending on the propagation environment. The objective of this paper is the adaptive resource allocation in MIMOOFDM system using the waterfilling algorithm. Water filling solution is implemented for allocating the power in order to increase the channel capacity. The total system capacity is maximised subject to the constraints on total power, signal to noise ratio, and proportional fairness. Channel is assumed as a flat fading channel and the comparison is made for different 2x2, 2x3, 3x2 and 4x4 MIMO-OFDM systems using waterfilling algorithm with allocated power. Also in order to prove that the MIMOOFDM with waterfilling algorithm provides the best performance a comparison with various SISO - OFDM is done.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
An Approach to Improve the Quality of Service in OFDMA Relay Networks via Re-...iosrjce
With the next-generation cellular networks making a transition toward smaller cells, two-hop
orthogonal frequency-division multiple access (OFDMA) relay networks have become a dominant, mandatory
component in the 4G standards (WiMAX802.16j, 3GPP LTE-Adv.). Here we are using the multicasting strategy
Given the growing importance of multimedia broadcast and multicast services (MBMS) in 4G networks, the
latter forms the focus of this project. The main aim of this project is to improve the performance of the OFDMA
based relay networks. The OFDMA transmission Scheme is a widely accepted scheme for improving the quality
and speed of communication over the 4G cellular network. There are two different models designed for OFDMA
relay networks .Distributed (DP) and Contiguous (CP) permutations. We are checking the performance of two
algorithms The linear programming algorithm and the greedy algorithm by using two models of OFDMA for
multicast scheduling and after performance evaluation we select the best model and the algorithm for
transmission. We further improve the throughput via retransmission of lost packets during data transfer over the
specified network. We can detect the packet loss by packet synchronization technique and a request will be sent
by the destination for re-sending the lost packets which is called as Re-Transmission.[1]
Ofdm mimo and v-blast algorithm-key to high speed wireless communicationIAEME Publication
This document provides an overview of OFDM-MIMO technology for high-speed wireless communication. It discusses how OFDM divides a high-rate data stream into parallel lower-rate substreams that are transmitted over multiple carriers. MIMO is then used to further improve data rates and quality of service by exploiting multiple antennas at the transmitter and receiver. The document also describes V-BLAST, an algorithm used in MIMO systems to separate simultaneously transmitted signals at the receiver through ordered cancellation.
New Technique Combining the Tone Reservation Method with Clipping Technique t...IJECEIAES
Nonlinear distortions and impairments appear in multicarrier signal with high fluctu- ations when amplified by a Radio Frequency Power Amplifier (RF PA). This article is a contribution to improving the Tone Reservation (TR) method dedicated to reducing fluctuations in the Orthogonal Frequency Division Multiplexing (OFDM) modulation. This method exploits the null sub-carriers in communications standards in order to generate a correction signal used to reduce the Peak-to-Average Power Ratio (PAPR) with nevertheless limited performances due to the reduced number of these sub-carriers. For this purpose, our contribution is to combine the TR method with the Clipping (CL) method to improve the PAPR reduction without significantly impacting the quality of transmissions. We also show the gain provided by this strategy compared to the use of classical methods. Experiments using a simulated example on a complete WiMax 802:16e transmitter have been made in order to investigate the PAPR reduction performances on presence of the non-linear Power Amplifier model based on gain compression response and phase distortion.
ESTIMATION AND COMPENSATION OF INTER CARRIER INTERFERENCE IN WIMAX PHYSICAL L...ijngnjournal
WiMAX is Wireless Interoperability for Microwave Access has emerged as a promising solution for transmission of higher data rates for fixed and mobile applications. IEEE 802.16d and e are the standards proposed by WiMAX group for fixed and mobile. As the wireless channel have so many limitation Such as Multipath, Doppler spread, Delay spread and Line Of Sight (LOS)/Non Line Of Sight (NLOS) components. To attain higher data rates the Multi Carrier System with Multiple Input and Multiple Output (MIMO) is incorporated in the WiMAX. The Orthogonal Frequency Division Multiplexing (OFDM) is a multi carrier technique used with the WiMAX systems. In OFDM the available spectrum is split into numerous narrow band channels of dissimilar frequencies to achieve high data rate in a multi path fading environment. And all these sub carriers are considered to be orthogonal to each other. As the number of sub carriers is increased there is no guarantee of sustained orthogonality, i.e. at some point the carriers are not
independent to each other, and hence where the orthogonality can be loosed which leads to interference and also owing to the synchronization between transmitter and receiver local oscillator, it causes interference known as Inter Carrier Interference (ICI). The systems uses MIMO-OFDM will suffer with the effects of ICI and Carrier Frequency Offset (CFO) “ε”. However these affect the power leakage in the midst of sub carriers, consequently degrading the system performance. In this paper a new approach is proposed in order to reduce the ICI caused in WiMAX and improve the system performance. In this scheme at the transmitter side the modulated data and a few predefined pilot symbols are mapped onto the non
neighboring sub carriers with weighting coefficients of +1 and -1. With the aid of pilot symbols the frequency offset is exactly estimated by using Maximum Likelihood Estimation (MLE) and hence can be minimized. At demodulation stage the received signals are linearly combined along with their weighted
coefficients and pilot symbols, called as Pilot Aided Self Cancellation Method (PASCS). And also to realize the various wireless environments the simulations are carried out on Stanford University Interim (SUI) channels. The simulation results shows that by incorporating this method into WiMAX systems it performs better when the Line Of Sight (LOS) component is present in the transmission and also it improves the Bit Error Rate (BER) and Carrier to Interference Ratio (CIR). The CIR can be improved 20 dB. In this paper the effectiveness of PASCS scheme is compared with the Self Cancellation Method (SCM). It provides accurate estimation of frequency offset and when residual CFO is less significant the ICI can be diminished successfully.
This document summarizes a research project comparing wavelet packet based MC-CDMA with conventional MC-CDMA using the Hilbert-Huang transform tool. The research aims to show that wavelet packet based MC-CDMA has better bit error rate performance than conventional MC-CDMA in dealing with channel fading and interference. It provides background on MC-CDMA and wavelet packet techniques. It outlines the methodology which involves simulation using MATLAB and the Hilbert-Huang transform tool for spectral analysis. The expected outcome is that wavelet packet MC-CDMA will demonstrate comparative superiority over conventional MC-CDMA.
Peak to Average Power Ratio Reduction in Mc Cdma System by Using Pulse Shapin...IOSR Journals
Abstract: One of the drawback of multicarrier code division multiple access (MC CDMA) is the high peak to
average power ratio (PAPR). In this paper A novel scheme based on pulse shaping described for PAPR
reduction. Here three different pulse shaping filters (Raised cosine, Sinc power pulse and Nyqist pulse) are
described for PAPR reduction in MC CDMA system. The method is based on the proper selection of the pulses
for shaping the different sub carriers of the MC CDMA modulation scheme. It is shown by computer simulation
that the scheme achieves the significant improvement in PAPR reduction in MC CDMA system. Its
implementation complexity is much low in comparison to the previous published methods. Thus pulse shaping
technique can be used not only to shape the spectrum of the transmitted signal but also to reduce its PAPR. In
computer simulation It is observed that by using nyquist pulse near about 6.8 db PAPR is obtained. Which is
considerable PAPR reduction than a PAPR value of Original MC CDMA signal
Keywords: MC CDMA, PAPR, PULSE SHAPING, BPSK
WRAP is a medium access control (MAC) protocol for wavelength-routed passive optical networks (WR-PONs) that does not require a separate control channel, carrier sensing, or centralized scheduling. Each node has a single tunable transmitter and fixed receiver. Access is regulated through wavelength allocations made by destination nodes in response to requests. Simulations test three allocation algorithms and show the Preferential/Random algorithm provides better performance than alternatives. WRAP performance is also compared to two other applicable protocols, showing WRAP enables high utilization over a wide range of traffic conditions while guaranteeing minimum bandwidth between nodes.
This document discusses various techniques for reducing peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. It describes common PAPR reduction techniques such as partial transmit sequence (PTS), selective mapping (SLM), tone injection, peak cancellation, and peak windowing. It analyzes these techniques based on parameters like distortion, power increase, data rate loss, and bit error rate improvement. The document concludes that while SLM is better for PAPR reduction as it does not cause out-of-band radiation or degrade bit error rate performance, it has the drawback of increased complexity with larger number of subcarriers or phase sequences.
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.
Design Considerations for Converged Optical Ethernet NetworksVishal Sharma, Ph.D.
Transport networks have evolved to support a variety of traffic types over greater distances due to technologies like WDM and DWDM. This has led to a transition from voice-dominated to multi-service networks. Advances in optical networking components like EDFAs, AWGs, and ROADMs along with multi-service platforms have enabled direct transport of Ethernet frames over optical wavelengths without intermediate protocols. Further standards development aims to provide carrier-class qualities to Ethernet while optical networking seeks greater flexibility through technologies like DOADMs. Future networks will require dynamic bandwidth allocation and lower-cost metro access solutions.
Design of time division multiplexing/wavelength division multiplexing passiv...IJECEIAES
This paper presents the design of time division multiplexing-wavelength division multiplexing-passive optical network (TDM-WDM PON). In this design, the current TDM PON is incorporated with the proposed WDM-PON in order to design a high-capacity network with lower loss requirements. The design has been simulated using OptiSystem software. The upstream wavelength for WDM is between 1,530.334 to 1,542.142 nm while for TDM is 1,310 nm. The downstream wavelength for WDM is from 1,569.865 to 1,581.973 nm, while for TDM is 1,490 nm. Based on the result, it is found that the proposed network is capable to support up to 64 customers with a bit rate of 2.5 Gbps.
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).
This paper analyzes the performance of three routing protocols (AODV, DSDV, OLSR) for mobile WiMAX networks using the random direction mobility model in NS3 simulator. The protocols are evaluated based on routing overhead, packet delivery ratio, throughput, end-to-end delay, and packet loss. The results found that OLSR protocol outperformed AODV and DSDV, with lower routing overhead and higher packet delivery ratio, demonstrating improved efficiency for WiMAX networks.
Optical space division multiplexing uses multiple cores or modes in optical fibers to increase transmission capacity. A history of the technology was provided, noting the progression from single mode fibers to coherent detection and polarization multiplexing. Limits with single mode fibers were discussed, along with ways that multi-core and multi-mode fibers can overcome capacity constraints through spatial multiplexing across fiber cores and modes. Recent demonstrations showed record capacities of 57.6 Tb/s over multi-mode fiber and 24 Tb/s over hollow-core fiber. Integration challenges with spatial division multiplexing were also outlined.
An optical add-drop multiplexer (OADM) is a device used in WDM systems that allows routing of different fiber channels into or out of a single mode fiber. It consists of an optical demultiplexer, multiplexer, and method to reconfigure signal paths. The demultiplexer separates wavelengths on input fiber to ports. OADMs can add or drop single or multiple wavelengths from a fully multiplexed signal, allowing intermediate sites on a fiber link to access the connection. Additional wavelengths can be added or dropped by successive OADMs as needed in the network.
1. The document discusses adopting layer 2 Ethernet switching over DWDM networks to address bandwidth demands of new media-rich applications.
2. Traditional SONET/SDH networks are overloaded and complex to scale, while Ethernet over SONET wastes bandwidth.
3. Layer 2 Ethernet switching over DWDM networks can eliminate unnecessary protocol conversions, reduce costs, simplify operations, and provide optimal scalability to meet rising bandwidth demands more cost-effectively.
DESIGN OF A COMPACT CIRCULAR MICROSTRIP PATCH ANTENNA FOR WLAN APPLICATIONS pijans
This paper presents the design of a compact circular microstrip patch antenna for WLAN applications which covers the band 5.15 to 5.825 GHz. The antenna is designed using 1.4mm thick FR-4 (lossy)substrate with relative permittivity 4.4 and a microstrip line feed is used. The radius of the circular patch is chosen as 7.62mm. To reduce the size and enhance the performance of the proposed antenna, a circular slot is loaded on circular patch and a square slot is etched on the ground plane of dimension 30mm×30mm. Design of the antenna is carried out using CST Microsoft Studio Sonimulation Software. The proposed antenna resonates at 5.5 GHz with a wider bandwidth of 702 MHz and it provides low return loss of -31.58 dB, good gain of 3.23 dB and directivity of 4.28 dBi and high efficiency of around 79% against the resonance frequency. The geometry of the proposed circular antenna with reduced size and its various performance parameters such as return loss, bandwidth, VSWR, gain, directivity, efficiency and radiation pattern plots are presented and discussed.
1. The document discusses Filter Bank Multi-Carrier (FBMC) as an alternative to OFDM that provides better spectral properties and allows for MIMO techniques to be applied more easily.
2. It presents a spreading technique for FBMC symbols using Hadamard matrices that cancels imaginary interference and allows restoration of complex orthogonality within transmission blocks. This reduces complexity compared to other spreading approaches.
3. The performance of FBMC and OFDM is analyzed in double-selective channels at high speeds, and it is shown that FBMC can achieve a higher signal-to-interference ratio than OFDM in such conditions. Bit error rate is also derived for various modulation schemes.
Adaptive Resource Allocation in MIMO-OFDM Communication Systemijsrd.com
Multiple Input and Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) system have the potential to achieve very high capacity depending on the propagation environment. The objective of this paper is the adaptive resource allocation in MIMOOFDM system using the waterfilling algorithm. Water filling solution is implemented for allocating the power in order to increase the channel capacity. The total system capacity is maximised subject to the constraints on total power, signal to noise ratio, and proportional fairness. Channel is assumed as a flat fading channel and the comparison is made for different 2x2, 2x3, 3x2 and 4x4 MIMO-OFDM systems using waterfilling algorithm with allocated power. Also in order to prove that the MIMOOFDM with waterfilling algorithm provides the best performance a comparison with various SISO - OFDM is done.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
An Approach to Improve the Quality of Service in OFDMA Relay Networks via Re-...iosrjce
With the next-generation cellular networks making a transition toward smaller cells, two-hop
orthogonal frequency-division multiple access (OFDMA) relay networks have become a dominant, mandatory
component in the 4G standards (WiMAX802.16j, 3GPP LTE-Adv.). Here we are using the multicasting strategy
Given the growing importance of multimedia broadcast and multicast services (MBMS) in 4G networks, the
latter forms the focus of this project. The main aim of this project is to improve the performance of the OFDMA
based relay networks. The OFDMA transmission Scheme is a widely accepted scheme for improving the quality
and speed of communication over the 4G cellular network. There are two different models designed for OFDMA
relay networks .Distributed (DP) and Contiguous (CP) permutations. We are checking the performance of two
algorithms The linear programming algorithm and the greedy algorithm by using two models of OFDMA for
multicast scheduling and after performance evaluation we select the best model and the algorithm for
transmission. We further improve the throughput via retransmission of lost packets during data transfer over the
specified network. We can detect the packet loss by packet synchronization technique and a request will be sent
by the destination for re-sending the lost packets which is called as Re-Transmission.[1]
Ofdm mimo and v-blast algorithm-key to high speed wireless communicationIAEME Publication
This document provides an overview of OFDM-MIMO technology for high-speed wireless communication. It discusses how OFDM divides a high-rate data stream into parallel lower-rate substreams that are transmitted over multiple carriers. MIMO is then used to further improve data rates and quality of service by exploiting multiple antennas at the transmitter and receiver. The document also describes V-BLAST, an algorithm used in MIMO systems to separate simultaneously transmitted signals at the receiver through ordered cancellation.
New Technique Combining the Tone Reservation Method with Clipping Technique t...IJECEIAES
Nonlinear distortions and impairments appear in multicarrier signal with high fluctu- ations when amplified by a Radio Frequency Power Amplifier (RF PA). This article is a contribution to improving the Tone Reservation (TR) method dedicated to reducing fluctuations in the Orthogonal Frequency Division Multiplexing (OFDM) modulation. This method exploits the null sub-carriers in communications standards in order to generate a correction signal used to reduce the Peak-to-Average Power Ratio (PAPR) with nevertheless limited performances due to the reduced number of these sub-carriers. For this purpose, our contribution is to combine the TR method with the Clipping (CL) method to improve the PAPR reduction without significantly impacting the quality of transmissions. We also show the gain provided by this strategy compared to the use of classical methods. Experiments using a simulated example on a complete WiMax 802:16e transmitter have been made in order to investigate the PAPR reduction performances on presence of the non-linear Power Amplifier model based on gain compression response and phase distortion.
ESTIMATION AND COMPENSATION OF INTER CARRIER INTERFERENCE IN WIMAX PHYSICAL L...ijngnjournal
WiMAX is Wireless Interoperability for Microwave Access has emerged as a promising solution for transmission of higher data rates for fixed and mobile applications. IEEE 802.16d and e are the standards proposed by WiMAX group for fixed and mobile. As the wireless channel have so many limitation Such as Multipath, Doppler spread, Delay spread and Line Of Sight (LOS)/Non Line Of Sight (NLOS) components. To attain higher data rates the Multi Carrier System with Multiple Input and Multiple Output (MIMO) is incorporated in the WiMAX. The Orthogonal Frequency Division Multiplexing (OFDM) is a multi carrier technique used with the WiMAX systems. In OFDM the available spectrum is split into numerous narrow band channels of dissimilar frequencies to achieve high data rate in a multi path fading environment. And all these sub carriers are considered to be orthogonal to each other. As the number of sub carriers is increased there is no guarantee of sustained orthogonality, i.e. at some point the carriers are not
independent to each other, and hence where the orthogonality can be loosed which leads to interference and also owing to the synchronization between transmitter and receiver local oscillator, it causes interference known as Inter Carrier Interference (ICI). The systems uses MIMO-OFDM will suffer with the effects of ICI and Carrier Frequency Offset (CFO) “ε”. However these affect the power leakage in the midst of sub carriers, consequently degrading the system performance. In this paper a new approach is proposed in order to reduce the ICI caused in WiMAX and improve the system performance. In this scheme at the transmitter side the modulated data and a few predefined pilot symbols are mapped onto the non
neighboring sub carriers with weighting coefficients of +1 and -1. With the aid of pilot symbols the frequency offset is exactly estimated by using Maximum Likelihood Estimation (MLE) and hence can be minimized. At demodulation stage the received signals are linearly combined along with their weighted
coefficients and pilot symbols, called as Pilot Aided Self Cancellation Method (PASCS). And also to realize the various wireless environments the simulations are carried out on Stanford University Interim (SUI) channels. The simulation results shows that by incorporating this method into WiMAX systems it performs better when the Line Of Sight (LOS) component is present in the transmission and also it improves the Bit Error Rate (BER) and Carrier to Interference Ratio (CIR). The CIR can be improved 20 dB. In this paper the effectiveness of PASCS scheme is compared with the Self Cancellation Method (SCM). It provides accurate estimation of frequency offset and when residual CFO is less significant the ICI can be diminished successfully.
This document summarizes a research project comparing wavelet packet based MC-CDMA with conventional MC-CDMA using the Hilbert-Huang transform tool. The research aims to show that wavelet packet based MC-CDMA has better bit error rate performance than conventional MC-CDMA in dealing with channel fading and interference. It provides background on MC-CDMA and wavelet packet techniques. It outlines the methodology which involves simulation using MATLAB and the Hilbert-Huang transform tool for spectral analysis. The expected outcome is that wavelet packet MC-CDMA will demonstrate comparative superiority over conventional MC-CDMA.
Peak to Average Power Ratio Reduction in Mc Cdma System by Using Pulse Shapin...IOSR Journals
Abstract: One of the drawback of multicarrier code division multiple access (MC CDMA) is the high peak to
average power ratio (PAPR). In this paper A novel scheme based on pulse shaping described for PAPR
reduction. Here three different pulse shaping filters (Raised cosine, Sinc power pulse and Nyqist pulse) are
described for PAPR reduction in MC CDMA system. The method is based on the proper selection of the pulses
for shaping the different sub carriers of the MC CDMA modulation scheme. It is shown by computer simulation
that the scheme achieves the significant improvement in PAPR reduction in MC CDMA system. Its
implementation complexity is much low in comparison to the previous published methods. Thus pulse shaping
technique can be used not only to shape the spectrum of the transmitted signal but also to reduce its PAPR. In
computer simulation It is observed that by using nyquist pulse near about 6.8 db PAPR is obtained. Which is
considerable PAPR reduction than a PAPR value of Original MC CDMA signal
Keywords: MC CDMA, PAPR, PULSE SHAPING, BPSK
WRAP is a medium access control (MAC) protocol for wavelength-routed passive optical networks (WR-PONs) that does not require a separate control channel, carrier sensing, or centralized scheduling. Each node has a single tunable transmitter and fixed receiver. Access is regulated through wavelength allocations made by destination nodes in response to requests. Simulations test three allocation algorithms and show the Preferential/Random algorithm provides better performance than alternatives. WRAP performance is also compared to two other applicable protocols, showing WRAP enables high utilization over a wide range of traffic conditions while guaranteeing minimum bandwidth between nodes.
This document discusses various techniques for reducing peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. It describes common PAPR reduction techniques such as partial transmit sequence (PTS), selective mapping (SLM), tone injection, peak cancellation, and peak windowing. It analyzes these techniques based on parameters like distortion, power increase, data rate loss, and bit error rate improvement. The document concludes that while SLM is better for PAPR reduction as it does not cause out-of-band radiation or degrade bit error rate performance, it has the drawback of increased complexity with larger number of subcarriers or phase sequences.
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.
Design Considerations for Converged Optical Ethernet NetworksVishal Sharma, Ph.D.
Transport networks have evolved to support a variety of traffic types over greater distances due to technologies like WDM and DWDM. This has led to a transition from voice-dominated to multi-service networks. Advances in optical networking components like EDFAs, AWGs, and ROADMs along with multi-service platforms have enabled direct transport of Ethernet frames over optical wavelengths without intermediate protocols. Further standards development aims to provide carrier-class qualities to Ethernet while optical networking seeks greater flexibility through technologies like DOADMs. Future networks will require dynamic bandwidth allocation and lower-cost metro access solutions.
Design of time division multiplexing/wavelength division multiplexing passiv...IJECEIAES
This paper presents the design of time division multiplexing-wavelength division multiplexing-passive optical network (TDM-WDM PON). In this design, the current TDM PON is incorporated with the proposed WDM-PON in order to design a high-capacity network with lower loss requirements. The design has been simulated using OptiSystem software. The upstream wavelength for WDM is between 1,530.334 to 1,542.142 nm while for TDM is 1,310 nm. The downstream wavelength for WDM is from 1,569.865 to 1,581.973 nm, while for TDM is 1,490 nm. Based on the result, it is found that the proposed network is capable to support up to 64 customers with a bit rate of 2.5 Gbps.
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).
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Performance evaluation of VLC system using new modulation approachjournalBEEI
This document evaluates the performance of a new modulation scheme called catenated-OFDM for visible light communications (VLC) systems. Catenated-OFDM involves transmitting multiple OFDM signals simultaneously over different optical bands. The proposed system is simulated using Optisys software. Results show the system can achieve transmission distances of up to 12 meters for 2 dBm input power with 3 optical bands and a data rate of 10 Gbps. Higher data rates, up to 15 Gbps, are also possible. Increasing the number of optical bands or decreasing the data rate improves the receiver sensitivity. The catenated-OFDM approach shows potential for high-speed optical wireless communications.
This presentation summarizes photovoltaic and photoconductive modes of photo diodes, the differences between the two modes, and provides an introduction to wavelength division multiplexing (WDM) including its need, types, advantages/disadvantages, architecture, working, and implementation. The key points are that photovoltaic mode produces voltage without bias while photoconductive mode requires reverse bias, WDM uses different wavelengths to transmit multiple data channels over a single fiber increasing bandwidth capacity, and its architecture includes elements like optical line terminals and optical add-drop multiplexers.
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.
Optimal Channel and Relay Assignment in Ofdmbased Multi-Relay Multi-Pair Two-...ijcnes
Efficient utilization of radio resources in wireless networks is crucial and has been investigated extensively. This letter considers a wireless relay network where multiple user pairs conduct bidirectional communications via multiple relays based on orthogonal frequency-division multiplexing (OFDM) transmission. The joint optimization of channel and relay assignment, including subcarrier pairing, subcarrier allocation as well as relay selection, for total throughput maximization is formulated as a combinatorial optimization problem. Using a graph theoretical approach, we solve the problem optimally in polynomial time by transforming it into a maximum weighted bipartite matching (MWBM) problem. Simulation studies are carried out to evaluate the network total throughput versus transmit power per node and the number of relay nodes
Since the photonic layer is the cheapest on a per-bit, per-function basis, and since
the key imperative before operator's today is to bridge the yawning gap between
exponentially increasing data traffic on the one-hand, and flat-to-declining revenues
on the other, a tighter coupling between the packet and optical layers to derive
operational, management, and deployment efficiencies, has...
This document discusses space division multiplexing (SDM), a new technique for fiber optic communication that increases transmission capacity. SDM utilizes unused space within the core or additional fiber cores to establish independent transmission channels. There are two main SDM strategies: multi-core fiber which has multiple cores embedded in the cladding, and multi-mode fiber which supports propagation of multiple independent modes within a single core. SDM provides significant advantages like high scalability and the ability to achieve terabit per second throughput. When combined with software defined networking, SDM networks also enable efficient infrastructure utilization and flexible bandwidth provisioning. However, SDM also faces challenges like crosstalk between cores and high insertion losses.
In this work, high-speed transmission over the long-haul optical channel using orthogonal frequency division multiplexing (OFDM) was investigated. Furthermore, we recommend mixing polarization division multiplexing (PDM) with coherent OFDM (CO-OFDM) and quadrature amplitude modulation (16-QAM) to improve spectral efficiency (SE) while transmitting over a wavelength division multiplexing (WDM) system.
An 800 Gb/s WDM PDM-CO-OFDM-16QAM transmission system with various channel spacing of 100 GHz, 50 GHz, and 25 GHz is examined utilizing the OptiSystem (2021) version 18.0 software package over ten spans of 60 km standard single-mode fiber (SSMF). Different channel spacing WDM systems have been compared in terms of performance and SE. The results reveal that the WDM system with 100 GHz channel spacing has a longer transmission range and needs minimal optical signal to noise ratio (OSNR) at the reception. The 25 GHz channel spacing WDM system exceeds the others in terms of SE. Further, the effect of ultra-low loss and large effective area fiber in lowering span loss and nonlinear effects for
25 GHz channel spacing WDM system is investigated. The findings show that the system performance with the new fiber outperforms the SSMF.
The acceptable bit error rate (BER) for this study is 0.033 (20% concatenated forward error correction (FEC) threshold).
The document analyzes the performance of IEEE 802.16d under the Stanford University Interim (SUI) channel model. It investigates the bit error rate of IEEE 802.16d using different SUI channel models and digital modulations like BPSK and QPSK. The results show the BER performance for different SUI channel models and modulations.
Analysis of System Capacity and Spectral Efficiency of Fixed-Grid NetworkIJCNCJournal
In this article, the performance of a fixed grid network is examined for various modulation formats to estimate the system's capacity and spectral efficiency. The optical In-phase Quadrature Modulator (IQM) structure is used to build a fixed grid network modulation, and the homodyne detection approach is used for the receiver. Data multiplexing is accomplished using the Polarization Division Multiplexed (PDM) technology. 100 Gbps, 150 Gbps, and 200 Gbps data rates are transmitted under these circumstances utilizing various modulation formats. Various pre-processing and signal recovery steps are explained by using modern digital signal processing systems. The achieved spectrum efficiencies for PM-QPSK, PM-8 QAM, and PM-16 QAM, respectively, were 2, 3, and 4 (bits/s)/Hz. Different modulation like PM-QPSK, PM-8-QAM, and PM-16-QAM each has system capacities of 8-9, 12-13.5, and 16-18 Tbps and it reaches transmission distances of 3000, 1300, and 700 kilometers with acceptable Bit Error Rate (BER≤ 2× 10-3) respectively. Peak optical power for received signal detection and full width at half maximum is noted for the different modulations under a fixed grind network.
Analysis of System Capacity and Spectral Efficiency of Fixed-Grid NetworkIJCNCJournal
The document analyzes the system capacity and spectral efficiency of a fixed-grid optical network using different modulation formats. It simulates a fixed-grid network using polarization division multiplexing and transmits 100-200 Gbps data rates using PM-QPSK, PM-8QAM, and PM-16QAM modulation. The achieved spectral efficiencies were 2, 3, and 4 bits/s/Hz respectively. The modulation formats provided system capacities of 8-9, 12-13.5, and 16-18 Tbps, reaching transmission distances of 3000, 1300, and 700 km with a bit error rate below 2x10-3. It examines the received optical power and bandwidth requirements for different modulations in a fixed grid
A Novel Timer-Based Hybrid Rerouting Algorithm for Improving Resource Utiliza...IJERA Editor
In this paper we investigate hybrid rerouting and minimization of incurred service disruption period due to
rerouting in Wavelength Division Multiplexed (WDM) transparent optical network. One limitation of such a
network is the wavelength continuity constraint which does not allow a circuit to be placed on a non
wavelength-continuous route. The impact of this constraint might have a severe consequence on the
performance of transparent optical networks especially in terms of rejection ratio ant it is especially severe when
traffic demands are unpredictable and characterized by random arrivals and departures. To alleviate the impact
of these constraints, either wavelength conversion or traffic rerouting can be used. Since, in the foreseeable
future, wavelength conversion is expected to remain an expensive technology, traffic rerouting is an attractive
alternative solution. Thus, we here propose to employ hybrid rerouting to improve the network performances.
Hybrid rerouting combines passive and active rerouting. Through simulation results, the performances of the
proposed algorithm in terms of rejection ratio are demonstrated to be promising while rerouting a small number
of already established lightpaths using Lightpath ReRouting (LRR). By rerouting a small number of existing
lightpaths using LRR, we hope that the incurred service disruption period due to rerouting is minimized.
WDM is a fiber optic technology that multiplexes multiple optical carrier signals onto a single optical fiber by using different wavelengths of laser light. This enables bidirectional communications over one fiber and increases network capacity. A WDM system uses a multiplexer to combine signals and a demultiplexer to separate them. CWDM and DWDM are two common types of WDM systems that differ in channel spacing and reach. CWDM uses wider spacing of 20nm between 1470-1610nm wavelengths, has a shorter reach of 100km, and is more cost-effective. DWDM more densely spaces narrow wavelengths, can reach thousands of kilometers with amplification, and supports higher speeds.
White Paper-Evolution from 10Gbps to 100Gbps for a Metro Network-hsSusmita Adhikari Joshi
This document discusses the evolution from 10G to 100G networks for metro applications. It describes how 100G technology can complement existing 10G infrastructure by utilizing unused wavelengths on fibers. A key consideration is maintaining economic viability while providing greater bandwidth efficiency. Direct detection is seen as more suitable than coherent detection for metro due to lower cost and complexity. The document outlines various technological requirements for a 100G network such as 100G transceivers, DWDM multiplexers, optical amplifiers, dispersion compensation, and FEC. It provides an example architecture for upgrading an existing 10G system to incorporate 100G services over longer distances.
Similar to RECONFIGURABLE OPTICAL ADD AND DROP MULTIPLEXERS A REVIEW (20)
NEW Current Issue - CALL FOR PAPERS - Electrical and Computer Engineering An ...ecij
Electrical & Computer Engineering: An International Journal (ECIJ) is a peer-reviewed open access journal calling for papers on topics related to electrical and computer engineering, including communications, control systems, integrated circuits, power systems, and signal processing. Authors are invited to submit original papers by August 7, 2021 via the journal's online submission system, with notification of acceptance by September 7 and final manuscripts due by September 15 for publication dates determined by the Editor-in-Chief.
Electrical & Computer Engineering: An International Journal (ECIJ)ecij
Electrical & Computer Engineering: An International Journal (ECIJ) is a peer-reviewed, open access journal that addresses the impacts and challenges of Electrical and Computer Engineering. The journal documents practical and theoretical results which make a fundamental contribution for the development Electrical and Computer Engineering.
Electrical & Computer Engineering: An International Journal (ECIJ)ecij
Electrical & Computer Engineering: An International Journal (ECIJ) is a peer-reviewed,
open access journal that address the impacts and challenges of Electrical and Computer
Engineering. The journal documents practical and theoretical results which make a fundamental
contribution for the development Electrical and Computer Engineering.
Electrical & Computer Engineering: An International Journal (ECIJ)ecij
Electrical & Computer Engineering: An International Journal (ECIJ) is a peer-reviewed,
open access journal that address the impacts and challenges of Electrical and Computer
Engineering. The journal documents practical and theoretical results which make a fundamental
contribution for the development Electrical and Computer Engineering.
Electrical & Computer Engineering: An International Journal (ECIJ)ecij
Electrical & Computer Engineering: An International Journal (ECIJ) is a peer-reviewed,
open access journal that address the impacts and challenges of Electrical and Computer
Engineering. The journal documents practical and theoretical results which make a fundamental
contribution for the development Electrical and Computer Engineering
This work investigates and evaluates the electric energy interruptions to the residential sector resulting from severe power outages. The study results show that this sector will suffer tangible and intangible losses should these outages occur during specific times, seasons, and for prolonged durations. To reduce these power outages and hence mitigate their adverse consequences, the study proposes practical measures that
can be adopted without compromising the consumers’ needs, satisfaction, and convenience.
GRID SIDE CONVERTER CONTROL IN DFIG BASED WIND SYSTEM USING ENHANCED HYSTERES...ecij
The standard grid codes suggested, that the wind generators should stay in connected and reliable active and reactive power should be provided during uncertainties. This paper presents an independent control of Grid Side Converter (GSC) for a doubly fed induction generator (DFIG). A novel GSC controller has
been designed by incorporating a new Enhanced hysteresis comparator (EHC) that utilizes the hysteresis band to produce the suitable switching signal to the GSC to get enhanced controllability during grid unbalance. The EHC produces higher duty-ratio linearity and larger fundamental GSC currents with
lesser harmonics. Thus achieve fast transient response for GSC. All these features are confirmed through
time domain simulation on a 15 KW DFIG Wind Energy Conversion System (WECS).
Electrical & Computer Engineering: An International Journal (ECIJ)ecij
Electrical & Computer Engineering: An International Journal (ECIJ) is a peer-reviewed,
open access journal that address the impacts and challenges of Electrical and Computer
Engineering. The journal documents practical and theoretical results which make a fundamental
contribution for the development Electrical and Computer Engineering.
PREPARATION OF POROUS AND RECYCLABLE PVA-TIO2HYBRID HYDROGELecij
Nano TiO2, one of the most effective photocatalysts, has extensive usein fields such as air purification,
sweage treatment, water spitting, reduction of CO2, and solar cells. Nowadays, the most promising method to
recycle nano TiO2during the photocatalysis is to immobilize TiO2onto matrix, such as polyvinyl alcohol
(PVA). However, due to the slow water permeability of PVA after cross-linking, the pollutants could not
contact with nano TiO2photocatalyst in time. To overcome this problem, we dispersed calcium carbonate
particles into a PVA-TiO2 mixture and then filmed the glass. PVA-TiO2-CaCO3 films were obtained by
drying. Through thermal treatment, we obtained the cross-linked PVA-TiO2-CaCO3 films. Finally, the
calcium carbonate in the film was dissolved by hydrochloric acid, and the porous PVA-TiO2 composite
photocatalyst was obtained. The results show the addition of CaCO3 has no obvious effect on PVA
cross-linking and that a large number of cavities have been generated on the surface and inside of porous
PVA-TiO2 hybrid hydrogel film. The size of the holes is about 5-15μm, which is consistent with that of
CaCO3.The photocatalytic rate constant of porous PVA-TiO2 hybrid hydrogel film is 2.49 times higher than
that of nonporous PVA-TiO2 hybrid hydrogel film.
4th International Conference on Electrical Engineering (ELEC 2020)ecij
4th International Conference on Electrical Engineering (ELEC 2020)aims to bring together researchers and practitioners from academia and industry to focus on recent systems and techniques in the broad field of Electrical Engineering. Original research papers, state-of-the-art reviews are invited for publication in all areas of Electrical Engineering.
Electrical & Computer Engineering: An International Journal (ECIJ)ecij
Electrical & Computer Engineering: An International Journal (ECIJ) is a peer-reviewed, open access journal that addresses practical and theoretical results in electrical and computer engineering. Topics of interest include communications, control systems, integrated circuits, power systems, and signal processing. Authors are invited to submit original papers by July 25, 2020 for peer-review and potential publication in September 2020.
4th International Conference on Bioscience & Engineering (BIEN 2020) ecij
The 4th International Conference on Bioscience & Engineering (BIEN 2020) will be held November 28-29, 2020 in Dubai, UAE. The conference will bring together researchers and practitioners from academia and industry to share knowledge on advances in bioscience and engineering. Authors are invited to submit original research papers and reviews by July 26, 2020 on topics including bioengineering, biochemistry, bioinformatics, biomedicine, and more. Selected papers will be published in conference proceedings and special issues of related journals.
Electrical & Computer Engineering: An International Journal (ECIJ)ecij
Scope & Topics
Electrical & Computer Engineering: An International Journal (ECIJ) is a peer-reviewed, open access journal that addresses the impacts and challenges of Electrical and Computer Engineering. The journal documents practical and theoretical results which make a fundamental contribution for the development Electrical and Computer Engineering.
Electrical & Computer Engineering: An International Journal (ECIJ)
ISSN: 2201-5957
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Authors are invited to submit papers for this journal through E-mail: ecijjournal@wireilla.com .
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GRID SIDE CONVERTER CONTROL IN DFIG BASED WIND SYSTEM USING ENHANCED HYSTERES...ecij
The document presents a novel control strategy using an Enhanced Hysteresis Controller (EHC) for the Grid Side Converter (GSC) of a DFIG-based wind energy system. The EHC improves upon standard hysteresis control by incorporating the DC link voltage as an input to the integrator, allowing for higher duty ratio linearity, larger fundamental GSC currents with less harmonics. Simulation results on a 15kW DFIG system show the EHC provides fast transient response for the GSC and regulates the DC link voltage with smooth GSC currents and power during grid disturbances like voltage dips. Comparisons to a system without GSC control show significant reductions in oscillations through use of the proposed EHC strategy.
UNION OF GRAVITATIONAL AND ELECTROMAGNETIC FIELDS ON THE BASIS OF NONTRADITIO...ecij
The traditional principle of solving the problem of combining the gravitational and electromagnetic fields is associated with the movement of the transformation of parameters from the electromagnetic to the gravitational field on the basis of Maxwell and Lorentz equations. The proposed non-traditional principle
is associated with the movement of the transformation of parameters from the gravitational to the electromagnetic field, which simplifies the process. Nave principle solving this task by using special physical quantities found by M. Planck in 1900: - Planck’s length, time and mass), the uniqueness of which is that they are obtained on the basis of 3 fundamental physical constants: the velocity c of light in vacuum, the Planck’s constant h and the gravitational constant G, which reduces them to the fundamentals of the Universe. Strict physical regularities were obtained for the based on intercommunication of 3-th
fundamental physical constants c, h and G, that allow to single out wave characteristic νG from G which is identified with the frequency of gravitational field. On this base other wave and substance parameters were strictly defined and their numerical values obtained. It was proved that gravitational field with the given wave parameters can be unified only with electromagnetic field having the same wave parameters that’s why it is possible only on Plank’s level of world creation. The solution of given problems is substantiated by well-known physical laws and conformities and not contradiction to modern knowledge about of material world and the Universe on the whole. It is actual for development of physics and other branches of science and technique.
USING MACHINE LEARNING TO BUILD A SEMI-INTELLIGENT BOT ecij
Nowadays, real-time systems and intelligent systems offer more and more control interface based on voice recognition or human language recognition. Robots and drones will soon be mainly controlled by voice. Other robots will integrate bots to interact with their users, this can be useful both in industry and entertainment. At first, researchers were digging on the side of "ontology reasoning". Given all the technical constraints brought by the treatment of ontologies, an interesting solution has emerged in last years: the construction of a model based on machine learning to connect a human language to a knowledge
base (based for example on RDF). We present in this paper our contribution to build a bot that could be used on real-time systems and drones/robots, using recent machine learning technologies.
MODELING AND SIMULATION OF SOLAR PHOTOVOLTAIC APPLICATION BASED MULTILEVEL IN...ecij
As the solar market is blooming and forecasted to continue this trend in the coming years. The efficiency and reliability of PV based system has always been a contention among researchers. Therefore, multilevel inverters are gaining more assiduity as it has multitude of benefits. It offers high power capability along with low output harmonics. The main disadvantage of MLI is its complexity and requirement of large
number of power devices and passive components. This paper presents a topology that achieves 37.5% reduction in number of passive components and power devices for five-level inverter. This topology is basically based on H-bridge with bi-directional auxiliary switch. This paper includes a stand-alone PV system in which designing and simulation of Boost converter connected with multilevel inverter for ac load is presented. Perturb and observe MPPT algorithm has been implemented to extract maximum power. The premier objective is to obtain Voltage with less harmonic distortion economically. Multicarrier Sinusoidal
PWM techniques have been implemented and analysed for modulation scheme. The Proposed system is simulated n MATLAB/Simulink platform.
Investigation of Interleaved Boost Converter with Voltage multiplier for PV w...ecij
This paper depicts the significance of Interleaved Boost Converter (IBC) with diode-capacitor multiplierwith PV as the input source. Maximum Power Point Tracking (MPPT) was used to obtain maximum power from the PV system. In this, interleaving topology is used to reduce the input current ripple, output voltage ripple, power loss and to suppress the ripple in battery current in the case of Plugin Hybrid Electric Vehicle (PHEV). Moreover, voltage multiplier cells are added in the IBC configuration to reduce the narrow turn-off periods. Two MPPT techniques are compared in this paper: i) Perturb and Observe (P&O) algorithm ii) Fuzzy Logic . The two algorithms are simulated using MATLAB and the comparison of performance parameters like the ripple is done and the results are verified.
A COMPARISON BETWEEN SWARM INTELLIGENCE ALGORITHMS FOR ROUTING PROBLEMSecij
Travelling salesman problem (TSP) is a most popular combinatorial routing problem, belongs to the class of NP-hard problems. Many approacheshave been proposed for TSP.Among them, swarm intelligence (SI) algorithms can effectively achieve optimal tours with the minimum lengths and attempt to avoid trapping in local minima points. The transcendence of each SI is depended on the nature of the problem. In our studies, there has been yet no any article, which had compared the performance of SI algorithms for TSP perfectly. In this paper,four common SI algorithms are used to solve TSP, in order to compare the performance of SI algorithms for the TSP problem. These algorithms include genetic algorithm, particle swarm optimization, ant colony optimization, and artificial bee colony. For each SI, the various parameters and operators were tested, and the best values were selected for it. Experiments oversome benchmarks fromTSPLIBshow that
artificial bee colony algorithm is the best one among the fourSI-basedmethods to solverouting problems like TSP.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
Discover the latest insights on Data Driven Maintenance with our comprehensive webinar presentation. Learn about traditional maintenance challenges, the right approach to utilizing data, and the benefits of adopting a Data Driven Maintenance strategy. Explore real-world examples, industry best practices, and innovative solutions like FMECA and the D3M model. This presentation, led by expert Jules Oudmans, is essential for asset owners looking to optimize their maintenance processes and leverage digital technologies for improved efficiency and performance. Download now to stay ahead in the evolving maintenance landscape.
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.
Software Engineering and Project Management - Software Testing + Agile Method...Prakhyath Rai
Software Testing: A Strategic Approach to Software Testing, Strategic Issues, Test Strategies for Conventional Software, Test Strategies for Object -Oriented Software, Validation Testing, System Testing, The Art of Debugging.
Agile Methodology: Before Agile – Waterfall, Agile Development.
Gas agency management system project report.pdfKamal Acharya
The project entitled "Gas Agency" is done to make the manual process easier by making it a computerized system for billing and maintaining stock. The Gas Agencies get the order request through phone calls or by personal from their customers and deliver the gas cylinders to their address based on their demand and previous delivery date. This process is made computerized and the customer's name, address and stock details are stored in a database. Based on this the billing for a customer is made simple and easier, since a customer order for gas can be accepted only after completing a certain period from the previous delivery. This can be calculated and billed easily through this. There are two types of delivery like domestic purpose use delivery and commercial purpose use delivery. The bill rate and capacity differs for both. This can be easily maintained and charged accordingly.
Rainfall intensity duration frequency curve statistical analysis and modeling...bijceesjournal
Using data from 41 years in Patna’ India’ the study’s goal is to analyze the trends of how often it rains on a weekly, seasonal, and annual basis (1981−2020). First, utilizing the intensity-duration-frequency (IDF) curve and the relationship by statistically analyzing rainfall’ the historical rainfall data set for Patna’ India’ during a 41 year period (1981−2020), was evaluated for its quality. Changes in the hydrologic cycle as a result of increased greenhouse gas emissions are expected to induce variations in the intensity, length, and frequency of precipitation events. One strategy to lessen vulnerability is to quantify probable changes and adapt to them. Techniques such as log-normal, normal, and Gumbel are used (EV-I). Distributions were created with durations of 1, 2, 3, 6, and 24 h and return times of 2, 5, 10, 25, and 100 years. There were also mathematical correlations discovered between rainfall and recurrence interval.
Findings: Based on findings, the Gumbel approach produced the highest intensity values, whereas the other approaches produced values that were close to each other. The data indicates that 461.9 mm of rain fell during the monsoon season’s 301st week. However, it was found that the 29th week had the greatest average rainfall, 92.6 mm. With 952.6 mm on average, the monsoon season saw the highest rainfall. Calculations revealed that the yearly rainfall averaged 1171.1 mm. Using Weibull’s method, the study was subsequently expanded to examine rainfall distribution at different recurrence intervals of 2, 5, 10, and 25 years. Rainfall and recurrence interval mathematical correlations were also developed. Further regression analysis revealed that short wave irrigation, wind direction, wind speed, pressure, relative humidity, and temperature all had a substantial influence on rainfall.
Originality and value: The results of the rainfall IDF curves can provide useful information to policymakers in making appropriate decisions in managing and minimizing floods in the study area.
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Applications of artificial Intelligence in Mechanical Engineering.pdfAtif Razi
Historically, mechanical engineering has relied heavily on human expertise and empirical methods to solve complex problems. With the introduction of computer-aided design (CAD) and finite element analysis (FEA), the field took its first steps towards digitization. These tools allowed engineers to simulate and analyze mechanical systems with greater accuracy and efficiency. However, the sheer volume of data generated by modern engineering systems and the increasing complexity of these systems have necessitated more advanced analytical tools, paving the way for AI.
AI offers the capability to process vast amounts of data, identify patterns, and make predictions with a level of speed and accuracy unattainable by traditional methods. This has profound implications for mechanical engineering, enabling more efficient design processes, predictive maintenance strategies, and optimized manufacturing operations. AI-driven tools can learn from historical data, adapt to new information, and continuously improve their performance, making them invaluable in tackling the multifaceted challenges of modern mechanical engineering.
Prediction of Electrical Energy Efficiency Using Information on Consumer's Ac...PriyankaKilaniya
Energy efficiency has been important since the latter part of the last century. The main object of this survey is to determine the energy efficiency knowledge among consumers. Two separate districts in Bangladesh are selected to conduct the survey on households and showrooms about the energy and seller also. The survey uses the data to find some regression equations from which it is easy to predict energy efficiency knowledge. The data is analyzed and calculated based on five important criteria. The initial target was to find some factors that help predict a person's energy efficiency knowledge. From the survey, it is found that the energy efficiency awareness among the people of our country is very low. Relationships between household energy use behaviors are estimated using a unique dataset of about 40 households and 20 showrooms in Bangladesh's Chapainawabganj and Bagerhat districts. Knowledge of energy consumption and energy efficiency technology options is found to be associated with household use of energy conservation practices. Household characteristics also influence household energy use behavior. Younger household cohorts are more likely to adopt energy-efficient technologies and energy conservation practices and place primary importance on energy saving for environmental reasons. Education also influences attitudes toward energy conservation in Bangladesh. Low-education households indicate they primarily save electricity for the environment while high-education households indicate they are motivated by environmental concerns.
Null Bangalore | Pentesters Approach to AWS IAMDivyanshu
#Abstract:
- Learn more about the real-world methods for auditing AWS IAM (Identity and Access Management) as a pentester. So let us proceed with a brief discussion of IAM as well as some typical misconfigurations and their potential exploits in order to reinforce the understanding of IAM security best practices.
- Gain actionable insights into AWS IAM policies and roles, using hands on approach.
#Prerequisites:
- Basic understanding of AWS services and architecture
- Familiarity with cloud security concepts
- Experience using the AWS Management Console or AWS CLI.
- For hands on lab create account on [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
# Scenario Covered:
- Basics of IAM in AWS
- Implementing IAM Policies with Least Privilege to Manage S3 Bucket
- Objective: Create an S3 bucket with least privilege IAM policy and validate access.
- Steps:
- Create S3 bucket.
- Attach least privilege policy to IAM user.
- Validate access.
- Exploiting IAM PassRole Misconfiguration
-Allows a user to pass a specific IAM role to an AWS service (ec2), typically used for service access delegation. Then exploit PassRole Misconfiguration granting unauthorized access to sensitive resources.
- Objective: Demonstrate how a PassRole misconfiguration can grant unauthorized access.
- Steps:
- Allow user to pass IAM role to EC2.
- Exploit misconfiguration for unauthorized access.
- Access sensitive resources.
- Exploiting IAM AssumeRole Misconfiguration with Overly Permissive Role
- An overly permissive IAM role configuration can lead to privilege escalation by creating a role with administrative privileges and allow a user to assume this role.
- Objective: Show how overly permissive IAM roles can lead to privilege escalation.
- Steps:
- Create role with administrative privileges.
- Allow user to assume the role.
- Perform administrative actions.
- Differentiation between PassRole vs AssumeRole
Try at [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
RECONFIGURABLE OPTICAL ADD AND DROP MULTIPLEXERS A REVIEW
1. Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
DOI : 10.14810/ecij.2014.3101 1
RECONFIGURABLE OPTICAL ADD AND DROP
MULTIPLEXERS A REVIEW
Devendra Kr.Tripathi, Pallavi Singh, N.K.Shukla and H.K.Dixit
Dept. of Electronics& Communication, University of Allahabad, Allahabad,
India
ABSTRACT
Optical multiplexing is the key function of a WDM network and reliable method for data transport
networks. WDM networks configured as rings/mesh along with Optical Add-Drop Multiplexers supports
added flexibility, simplicity and augment the spectral efficiency. Further enhancement achieved with
Reconfigurable OADM architectures, growing briskly along with automatic network management, let the
transport network to acclimatize with dynamically varying environment and flexibly respond to the
transport network changes. It permits single or many wavelengths to be added and/or dropped from a
transport fiber without optical-to-electrical-to-optical domain translation. Presently ROADM technology
has revolutionized optical networking and an inseparable part of modern optical communication offering
huge bandwidth for data transport at minimum expense. In this view the article presents comprehensive
study for numerous generations of ROADM and their architecture and persistent development.
KEYWORDS
Thin-film filters (TFFs), optical transport network (OTN), fully-reconfigurable OADM (FROADMS)
1. INTRODUCTION
Efforts to efficiently utilize the valuable communication resource various schemes have been
developed in the past to support numerous users within the same transmission medium. This
notion is referred as "multiplexing”, performed by exploiting orthogonality in various physical
dimensions. Thus number of techniques optical code division multiplexing
access(OCDMA),optical orthogonal frequency division multiplexing(OOFDM), polarization
division multiplexing(PDM),Optical time division multiplexing (OTDM) the next generation
transmission optical to optical scheme permits to surmount the signaling rate limits forced by
electronics and wavelength division multiplexing(WDM) devised to augment spectral efficiency.
Although WDM optical networks illustrated the short term answer for the steady raise in
bandwidth requirement. WDM networks exploit the enormous fiber bandwidth and transmit
several logical connections on the similar fiber [1]. Present growth in Dense Wavelength Division
Multiplex systems has made achievable transmission with hundreds of channels presenting total
capacities in surplus of Terabits/sec. Later on transmission with dense WDM (DWDM) channels
were put into practice as the competent exercise of fiber bandwidth, as economical and
trustworthy mechanism for shipping information bits in long haul in addition to the local metro
networks. However the conventional way by means of DWDM repeaters on the transmitting and
receiving channels were restricted, due to expenditure and systems complexity. So the competent
2. Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
2
exercise of fiber bandwidth was to exploit the costly network resource, for that numerous
alternatives have been attempted in conjunction with DWDM. Amongst Optical Add-Drop
Multiplexers (OADM) was one of the intelligent techniques for the handling of communications
signals. Add and drop multiplexer is the fundamental constructional block of fiber-optic
communication network constructions. It employs either unidirectional or bidirectional traffic
arrangements. The OADM selectively removes or adds wavelength from a multiplicity of
wavelengths in a fiber, and thus form traffic on the particular channel. It then adds in the same
direction of data flow the same wavelength, but with different data content [2]. A simpler OADM
which can be generally employed to add and drop wavelengths has been exhibited in the Fig.1,
depending upon the way of add/drop it can be classified in differently. Key types were fixed
OADM (FOADM), were dedicated for specific DWDM channels, and the
dynamic/Reconfigurable (ROADM) which can alter the selected channel routing to the optical
networks. However the FOADM requires optical-to-electrical and electrical-to-optical alterations
as well as required manual adjustments at EDFA because of channels being dropped or added.
Normally FOADM were built with thin-film filters (TFFs), along with stationary nature of the
arrangement as well as the requirement of manual changes so the operational cost were too high
for FOADMs, and were two major shortcomings [2-3].
OADM
IN
OUT
ADD
DROP
Figure1. Basic Add / Drop Multiplexer
Now to handle with dynamically varying traffic needs the scheme reconfigurable OADM
(ROADM) were devised ,which can alter the selected channel routing to the optical networks. It
reduces need for optical-to-electrical-to-optical (O-E-O) translations. An optical transport
network (OTN) containing ROADM nodes with different add/drop capabilities depicts numerous
flexibilities for the set up of light paths, reconfigurability. Such capabilities permit network
operators rapidly and flexibly act in response to network alterations. Reconfigurability in the
network does not need rescheduling for the carriers, and the light paths were set up or broken
down at once at any time. ROADMs do not add/drop the same wavelengths permanently and they
remotely organize to add/drop different wavelengths at different times. As well as there were no
need of high-speed electronic switching gear and thus minimizes capital expenses requirements
although due to electrical signal processing it loses the capacity little bit[4].ROADM has been
observed with numerous properties such as Colorless, Directionless, and Contention less. In the
Colorless, every add/drop port of an ROADM node should not be wavelength selective and the
architectures with Colorless permit any wavelength on an express fiber to be connected to any
add/drop transponder linked with that optical fiber.
The Directionless indicates that add/drop port at a node is not nodal degree selective. Here any
channel could be added on any port and can be directed to any other outbound nodal degree, and
vice versa. The directionless ROADMs were that in which the contention limitation were
eliminated, under the limit it is called contention less nodes. An ROADM with Colorless and
Directionless broadens notion to sharing a single group of transponders in between all
wavelengths from all express fiber directions. The contention factor is the maximum number of
the add/drop nodes. The add/drop contention in the network nodes is a source of light path
blocking, that adds extra constraints to the optical network planning and deteriorates the
3. Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
3
networks capacity. The Contention less denotes that within the ROADM node, the setup of cross-
connects between add/drop ports and outbound/inbound nodal degrees do not stop other cross-
connects from being set up; provided a free add/drop port is there and a free wavelength on an
outbound/inbound degree, a cross-connect can always be set up within the node[5].
Rigorous studies around mid 2000s such as two degree ROADM using PLC (planar light wave
circuit) switches were exercised, followed by N-degree ROADM employing wavelength selective
switch. Growth of PLC switches permitted the exercise of ring topologies and WSS switches to
interconnect rings and mesh topologies were presented[6].Next version of OXC employing fiber
uses regular AWG MUX/DEMUX were presented, wavelength contention resulting structural
design employing WSS(1: N) illustrated to join degrees to the A/D arrangement[7-8].The
blocking probability in FOADM system were evaluated and compared with flexible ROADM
counterpart, later investigated for the limited tunability in LROADM, can add/drop from only a
subset of adjoining wavelengths and low cost in contrast to fully-reconfigurable OADM
(FROADMS)[9-10].Afterward investigated for the non-Poisson traffic model, the model
calculates that traffic peakedness presented a significant part in calculating the blocking
performance[11].In this sight the article presents a brief very recent literature review. In the next
section brief theory of ROADM and its concise summary followed by conclusions have been
discussed.
2. THEORETICAL PRESENTMENT OF ROADM
ROADM permits remote configuration, reconfiguration, automatic power balancing and with
initial deployment of a system the planning of whole bandwidth task need not be carried out.
Initially ROADM viability appeared with long-haul DWDM equipment although by 2005, it
comes into view for metro services to deal along with the traffic driven by the growing need
for packet-based services. The ROADMs reconfiguration functions are achieved using various
switching technologies including liquid crystal, thermo optic , micro electromechanical
systems (MEMS)and tunable optical filter technology[12].ROADM were implemented in many
ways such as Fixed point ROADM. It is similar to fixed point OADMs though and has tunable
filters. Fixed point ROADMs employ wavelength blocker (WB) devices with high insertion loss
and integrated photonic light wave circuit (PLC). Wavelength selective ROADMs use flexible
filters, wavelength selective switches (WSS) and optical cross-connects. Study illustrated that
ROADM are a significant network element in the next generation all optical networks for the
applications in both long-haul and metro systems. It further enhances the communication
networks efficiency as well as dynamic connectivity in the optical networks with added network
survivability. It uses field-proven technology and components, contributing a reliable and low
cost solution due to switching [13].
ROADM networks are accompanied with fundamental components as Amplifiers (Pre-Amp &
Post-Amp), Dispersion Compensation unit, Transponders, Optical Service Channel, Optical
Power supervising and ROADM Subsystem. Basically ROADM can be classified as of different
types as Wavelength Selective Switches (WSS), Optical Cross-Connects (OXC), in the broadest
sense as Type I/II ROADM and Multidegree-ROADM.
4. Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
4
Wavelength Selective Switches (WSS)-
Wavelength Selective Switches (WSS) are the heart of the ROADM.WSS realizations employs
free-space optics and any wavelength, group, or band of wavelengths can be directed to any
output fiber. WSS’s are characteristically a single bulk diffraction grating, is shared for all the
demultiplexing and multiplexing.WSS permits any number of channels to exit any port. The
output patterns can be changed or reassigned to several output fibers through electrical interface.
Here n 1×N switches are needed for a 1×N WSS with n channels. For degree-N connectivity in a
ring-to-ring interconnect a 1×N WSS can be used either, adding/dropping channels as a ROADM
with one Express port and N-1 Drop the ports[14].To vary the fiber connectivity between the
transceiver and networks access ports for a given direction and colorless, directionless
realizations extra WSS’s were deployed [15].
DMUX
------/
______/
______/
INPUT
MUX
OUT
OUT
OUT
OUT
OUT
Figure2. Basic Wavelength Selective Switch
4x1 WSS
1xM WSS
A B C D
C O LO RLES S &
DIREC TIO NLES S -
DRO P PO RTS
DROP-DIRECTIONS ADD DIRECTIONS
COLORLESS &
DIRECTIONLESS
ADD-PORTS
PASSIVE
COMBINER
A B C D
Figure 3. Colorless and directionless access ports for ROADM of degree
Optical Cross-Connect-
Optical Cross-Connects (OXC) is one of the key network elements in the optical layer. These are
large switches employed to dynamically service as well as network restoration and enables
reconfigurable optical networks. OXC is employed for wavelength cross-connect switching and
important for the mesh networks. Through an increased number of connections and a higher level
of redundancy the mesh topology presents higher network capacity, efficiency, and reliability.
However increased hardware expenditure is a major barrier to the deployment of the mesh
networks. The OXC at every node in the transparent sub-networks are with polymer-on-silicon
5. Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
5
PLC platform which delivers low cost, small size, high optical performance, low electrical power
consumption, high yield, high throughput, short cycle time, and fast time to market [16].
OXC
OXC
OXC
OXC
OXC
OXC
OXC
O -E-O
SWITCH
O-E-O
SWITCH
OXC
OXC
OXC
OXC
OXC
OXC
OXC
Figure 4.ROADM Mesh Network with OXC as two interconnected islands
D
M
U
X
D
M
U
X
M
U
X
M
U
X
λ4
λ3
λ2
λ1
Wavelength ConvertersOptical switch Matrix
Figure5. OXC (4x4) architecture using wavelength converters
Two input fibers as illustrated in the fig.5 were each carrying two wavelengths. Either wavelength
can be switched to any of the four output ports. The OXC consists of three 2x2 switch elements.
Wavelength converters prevent cross-connected light waves from contending for the same output
fiber.OXC provides numerous key functions as service provisioning i.e. provision of light paths
in a large network in an automatic manner, ability to switch signals with arbitrary bit rates and
frame formats, protection (protects light paths against fiber cuts and equipment failures in the
network), and performance monitored test access and fault localization in large networks.
The Reconfigurable OADM of Type- I
The First Generation Type-I ROADM
It is the most elementary type of ROADM with fixed (colored) ports relies on the silica-on-silicon
arrayed (SSA) referred to as Type-I, costs less. Individually packaged chips were spliced all
together, namely SSA-waveguide grating (AWG) chips and polymer-on-silicon chips comprised
of switches. Demultiplexing/multiplexing, add/drop switching, and optical power monitoring/load
balancing is performed with SSA-based type- I- ROADM. It comprised of three AWG’s of thirty
two channels and two switches of sixteen channels, thus in total of five packages. Thirty two
6. Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
6
channels (N) in totality, on the both sides of a PCB complete package are mounted, along with
control electronics [16-19].
Figure 6. SSA-based Gen 1 Type I ROADM
The Second -Generation Type-I Reconfigurable OADM
The Reconfigurable OADM of second generation are also based on silica-on-silicon arrayed
(SSA) and implementation is through chip-to-chip connection along with additional integration,
well referred to as the Second Generation Type I ROADM. Together with numerous benefits, it
diminishes excess loss by replacing two fiber array pigtails with a single chip-to-chip coupling,
the space needed for fiber ribbons, splices were removed ,removal of fiber arrays amid chips and
a sub-assembly of hybrid ROADM, thus number channels are increased thus resulting in less
expenditure[20].
Type II Reconfigurable OADM
These types of networks offer colorless Add/Drop ports, and are based on the wavelength blocker
(WB), SSA approaches and may be further classified into number of generations.
First -Generation Type-II Reconfigurable OADM
This type of Reconfigurable OADM are mostly applied for the long-haul networks along with
50GHz interchannel spacing and these type of Reconfigurable OADM are based on free-space
optics that utilizes MEMS or LCD actuation. These are based on the generation-1 WB and SSA
schemes, the WB-based systems are also referred to as ‘Broadcast and Select’ architecture.
Together with use of tunable filters at the Drop ports and tunable lasers at the Add ports the ports,
are made colorless without having impact on the path [19].
DMUX
MUX
CONTROL
ELECTRONICS
DMUX
Ch1
Ch32
Ch1
Ch32
Tap-5%
TAP
15%
IN OUT
Ch1
Ch32
OUT IN
Ch32
Ch1
DATA
ADD
DROP
7. Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
7
DMUX
MUX
Receiver
1xN SPLITTER
Tunable Filter
Drop
SPLITTER
Tunable
Nx1 Combiner
SPLITTER
ADD
OCM
Wavelength
Blocker
Figure 7. (a) Gen 1 Type II ROADM -Wavelength blocker based broadcast and select Architecture
DMUX
MUX
DROP ADD
OXC OXC
Receivers Transmitters
OCM
OCM
Figure 8. (a) Gen-1 Type- II ROADM –PLC based-SSA approach Architecture
The Second-Generation Type-II Reconfigurable OADM
These types of architectures comprised of colorless Add and the Drop ports, cross-bar switches
for adding/dropping individual channels, optical power taps, integrated photodiodes for power
monitoring and channel power equalization. The Gen-2 SSA-based Type-II ROADM employ
polymer-on-silicon single-chip integrated channel switching/monitoring/equalizing/shuffling
photonic path for West/ East fiber pair[21].Although a self-balanced wavelength-supple ROADM
performance was actualized when this module is placed in between two silica-on-silicon AWG
Demux/Mux pairs.
Third-Generation Reconfigurable OADM
These are further enhanced version of ROADM architectures along with Polymer-on-silicon
integrated channels monitoring/ switching/equalizing chip along with polymer-on-silicon matrix
8. Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
8
switches, silica-on-silicon AWG chips and with East/West fiber pair, was referred to as
Generation 3- SSA-based Type-III ROADM having more competent.
Polymer
Arrays of
Switches/
Power
Monitors
OXC OXC
OXC OXC
Silicon
-on-Si
AWG
Silicon
-on-Si
AWG
Silicon-
on-Si
AWG
Silicon-
on-Si
AWG
ADD DROP
DROP ADD
IN
IN
OUT
OUT
FIBER-ARRAY FIBER-ARRAY
FIBER-ARRAY FIBER-ARRAY
SINGLE-FIBER
SINGLE-FIBER
SINGLE-FIBER
SINGLE-FIBER
Figure9. The Self balanced Generation-3 Type-II- ROADM
Multi-Degree ROADM
These are also an enhanced version of the ROADM’s where the degree of ROADM refers to the
number of bidirectional multi wavelength interfaces the device supports. Two DWDM trunk
directions facing East and West generally deployed with ring/linear networks are referred to as 2-
degree ROADM. Generally a given direction is with a pair of fiber for transmit /receive DWDM
line signal .The fiber pair which serves as given direction is referred to as a degree. The employed
ROADMs with higher than two degrees were usually called as multi-degree. Generally N-degree
ROADM were designed employing N Nx1 WSSs and with every WSS operates as a specified
degree, while extra WSSs can be deployed to implement the colorless access ports. ROADM
have numerous connectivity capacities and Connectivity depicts how many optical links a
particular ROADM may carry. Based on the degree ROADM were classified as degree-2
ROADMs or multiple-degree ROADMs, Two/higher degree ROADMs were employed in
ring/mesh networks and thus diminishes the expenditure ,viable option deployed for the next
generation optical network architectures depending on ROADMs [22-24].
9. Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
9
4-DEGREE
ROADM
DROP ADD
Figure10. A Full 2 degree ROADM AND 4-degree ROADM
3. SUMMARY-Basic ROADM Types
Basically for degree N node N fibers, wavelengths per fiber for NxN switches are required. For
drop operation tunable filters are used, NxM & MxN at A/D give full reconfigurability [19].As
illustrated in the table 1 and 2 which illustrates a concise summary of the different types of
ROADM architectures along with their respective pros and cons.
PRE
AMP
POST-A
MP
POST-A
MP
PRE-AMP
2X1
WSS
DMUX MUX
MUX
DMUX
2X1
WSS
EASTWEST
ADDDROP
ADD DROP
EXPRESS
EXPRESS
10. Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
10
EDFA
BLOCKER
SPLITTER COMBINER
λλλλ
λλλλ
BLOCKER
FIXED
FILTERS
FIXED
LASERS
Wavelength Blocker Based Broadcast & SelectType-I
EDFA
BLOCKER
SPLITTER COMBINER
BLOCKER
WavelengthBlockerBasedBroadcast & SelectType-II
Tunable Filters Tunable Lasers
EDFA
BLOCKER
SPLITTER COMBINER
BLOCKER
Wavelength BlockerBasedBroadcast & Select
HigherDegree ROADM
Tunable Filters Tunable Lasers
BLOCKER
Figure11. Wavelength blocker based broad cast and select ROADM Type’s
Integrated Dmux/switch/Mux
Type -I
DMUX
MUX
DMUX
MUX
OXC OXC
DMUX
DMUX
DMUX
DMUX
DMUX
DMUX
DMUX
DMUX
Type -I I
Highe r De gre e
ROADM
Figure12. Integrated DMux/Switch/Mux ROADM
11. Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
11
Table1.Types of ROADM’s and characteristics
Table2.Advantages & disadvantages of the ROADM’s
4. CONCLUSION
The article has presented a comprehensive study of the ROADM architectures, it avoids O-E-O
translations thus eliminates requirement of the costly high-speed switching electronics. Owing to
all optical transmission it has great potential than their electronic counterparts. ROADM enabled
service providers of Generation first and the second remotely add/ drop and redirect wavelengths
across the optical network. However shortcoming were in terms to offer a straightforward and
flexible answer for optical branching, one of the significant capability for the service providers
providing triple play services.Generation-3 ROADM are SSA-based, Polymer-on-silicon
integrated channels monitoring with matrix switches, fiber pair(East/West),higher degree
ROADM diminishes the expenditure with enhanced capability. Development of the future
generation ROADM architecture relies on the growth of supporting optical components maturity,
progress of integrated optics technology, upgrade capability of the equipment and novel
algorithms that will be add to development of the advanced ROADMs design. It is to be
developed around the future broadband communication network service needs, along with
considerable decrease in the operational costs, effective interoperability and the flawless service
evolution.
12. Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
12
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Authors
D. K. Tripathi received his B.Sc (A.U), B. Tech and M. Tech degree in Electronics and
Telecommunication engineering from the Department of Electronic &
University of Allahabad. Presently he is pursuing his Ph.D. degree in electronics engineering.
His area of interest includes Wireless c
communication. He is life member of ISTE.
Pallavi Singh received B.Tech and M.Tech degrees in electronics and Telecommunication
engineering from Department of Electronics & Communication University of Allahabad, in
1999 and 2002, respectively, where she is currently pursuing her Ph.D.degree in electronic
engineering.
Dr N.K. Shukla is Associate Professor in J.K.Institute of Applied Physics and Technology,
University of Allahabad (India). He started teaching in the department as lecturer, having
teaching experience of more than 17 Years. His main research are
communication and Holography. He has supervised many PhD candidates. He has published
a lot of papers in National, International journals and in National and International conferences. He is a
member of many academic bodies of other Uni
organizations like ISTE, IETE etc.
Dr. H.K. Dixit is presently Professor (E&C) and
Physics &Technology, University of Allahabad (India). He started
as lecturer in March 1975 and teaching experience of more than 38 Years. His main research
area is fiber optics communication and Holography. He has supervised numerous PhD
candidates and has published a lot of papers in the Nati
conferences. He is also member of RDC, academic bodies of other University, Institution, and life member
and fellow in organizations like ISTE, IETE etc.
Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
M. Mezhoudi et al., “The value of multiple degree ROADMs on metropolitan network economics,” in
–8.
K. Grobe, “Applications of ROADMs and control planes in metro and regional networks,” in Proc.
received his B.Sc (A.U), B. Tech and M. Tech degree in Electronics and
Telecommunication engineering from the Department of Electronic & Communication,
University of Allahabad. Presently he is pursuing his Ph.D. degree in electronics engineering.
His area of interest includes Wireless communication technology and fiber optics
communication. He is life member of ISTE.
received B.Tech and M.Tech degrees in electronics and Telecommunication
engineering from Department of Electronics & Communication University of Allahabad, in
1999 and 2002, respectively, where she is currently pursuing her Ph.D.degree in electronic
Associate Professor in J.K.Institute of Applied Physics and Technology,
University of Allahabad (India). He started teaching in the department as lecturer, having
teaching experience of more than 17 Years. His main research area is fiber optics
communication and Holography. He has supervised many PhD candidates. He has published
a lot of papers in National, International journals and in National and International conferences. He is a
member of many academic bodies of other University and institution, and life member and fellow in
is presently Professor (E&C) and the former H.O.D J.K. Institute of Applied
Physics &Technology, University of Allahabad (India). He started teaching in the department
as lecturer in March 1975 and teaching experience of more than 38 Years. His main research
area is fiber optics communication and Holography. He has supervised numerous PhD
candidates and has published a lot of papers in the National, International journals, International
conferences. He is also member of RDC, academic bodies of other University, Institution, and life member
and fellow in organizations like ISTE, IETE etc.
Electrical & Computer Engineering: An International Journal (ECIJ) Volume 3, Number 1, March 2014
13
M. Mezhoudi et al., “The value of multiple degree ROADMs on metropolitan network economics,” in
K. Grobe, “Applications of ROADMs and control planes in metro and regional networks,” in Proc.
received his B.Sc (A.U), B. Tech and M. Tech degree in Electronics and
Communication,
University of Allahabad. Presently he is pursuing his Ph.D. degree in electronics engineering.
fiber optics
received B.Tech and M.Tech degrees in electronics and Telecommunication
engineering from Department of Electronics & Communication University of Allahabad, in
1999 and 2002, respectively, where she is currently pursuing her Ph.D.degree in electronic
Associate Professor in J.K.Institute of Applied Physics and Technology,
University of Allahabad (India). He started teaching in the department as lecturer, having
a is fiber optics
communication and Holography. He has supervised many PhD candidates. He has published
a lot of papers in National, International journals and in National and International conferences. He is a
versity and institution, and life member and fellow in
H.O.D J.K. Institute of Applied
teaching in the department
as lecturer in March 1975 and teaching experience of more than 38 Years. His main research
area is fiber optics communication and Holography. He has supervised numerous PhD
onal, International journals, International
conferences. He is also member of RDC, academic bodies of other University, Institution, and life member