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5G Coupler Design for Intelligent Transportation System (ITS) Application IJECEIAES
Aiming to achieve 3-dB coupling, operating in fifth generation (5G) technologies, this paper introduces a new design of tight coupling coupler that will be operated in 5G technologies. Two stubs and two slots have been implemented into the 3-dB coupler design in order to achieve impedance matching between the ports and to give better coupling performances, respectively. Moreover, a study on the stubs’ and slots’ effects towards the S31 of the 3-dB coupler has also been presented in this paper. The proposed coupler is designed on Rogers RO4003C substrate. The simulation results and the analytical study on the stubs and slots implementation show that both stubs and slots affect the performance of the coupling coefficient.
A Potent MIMO–OFDM System Designed for Optimum BER and its Performance Anal...inventionjournals
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.
BER Performance of MPSK and MQAM in 2x2 Almouti MIMO Systemsijistjournal
Almouti published the error performance of the 2x2 space-time transmit diversity scheme using BPSK. One of the key techniques employed for correcting such errors is the Quadrature amplitude modulation (QAM) because of its efficiency in power and bandwidth.. In this paper we explore the error performance of the 2x2 MIMO system using the Almouti space-time codes for higher order PSK and M-ary QAM. MATLAB was used to simulate the system; assuming slow fading Rayleigh channel and additive white Gaussian noise. The simulated performance curves were compared and evaluated with theoretical curves obtained using BER tool on the MATLAB by setting parameters for random generators. The results shows that the technique used do find a place in correcting error rates of QAM system of higher modulation schemes. The model can equally be used not only for the criteria of adaptive modulation but for a platform to design other modulation systems as well.
A new look on CSI imperfection in downlink NOMA systemsjournalBEEI
Observing that cooperative scheme benefits to non-orthogonal multiple access (NOMA) systems, we focus on system performance analysis of downlink. However, spectrum efficiency is still high priority to be addressed in existing systems and hence this paper presents full-duplex enabling in NOMA systems. Other challenge needs be considered related to channel state information (CSI). In particular, we derive closedform expressions of outage probability for such NOMA systems under the presence of CSI imperfection. Furthermore, to fully exploit practical environment, we provide system model associated with Nakagami-m fading. The Monte-Carlo simulations are conducted to verify the exactness of considered systems.
Effect on Channel Capacity of Multi-User MIMO System in Crowded AreaIJEEE
Multiple-Input Multiple-Output (MIMO) and Multi-User
MIMO (MU-MIMO) systems have been expected to
improve the channel capacity over a limited bandwidth of
existing networks.
Performance analysis of beam divergence propagation through rainwater and sno...journalBEEI
In the present work the future communication requirements need to fulfill with high data rate, FSO (free space optic) with it is tremendous potential is the solution. This research observed the effectiveness analysis of FSO systems by modifying one of the most important FSO parameters beam divergence, under the most affected weather attenuating condition Rainwater and snow pack. The simulation is obtained and analyzed under single channels CSRZ-FSO (carrier-suppressed return-to-zero/free space optical) systems having capacity of 40 Gbps between two transceivers with variable distance. The connection is presently under 5 meteorological turbulences (light rain, medium rain, wet snow, heavy rain and dry snow). The results show the heavy rain and dry snow have a very high attenuation carried out in terms of Q-factor. this result led us to conclude that small divergence offers significant performance improvement for FSO link and this performance decrease every time the beam divergence increase, Therefore, to build inexpensive and reliable transmission media, we go with new method that still in the experiment area called hybrid RF/FSO (radio frequency/free space optical) that compatible with atmospherically status.
5G Coupler Design for Intelligent Transportation System (ITS) Application IJECEIAES
Aiming to achieve 3-dB coupling, operating in fifth generation (5G) technologies, this paper introduces a new design of tight coupling coupler that will be operated in 5G technologies. Two stubs and two slots have been implemented into the 3-dB coupler design in order to achieve impedance matching between the ports and to give better coupling performances, respectively. Moreover, a study on the stubs’ and slots’ effects towards the S31 of the 3-dB coupler has also been presented in this paper. The proposed coupler is designed on Rogers RO4003C substrate. The simulation results and the analytical study on the stubs and slots implementation show that both stubs and slots affect the performance of the coupling coefficient.
A Potent MIMO–OFDM System Designed for Optimum BER and its Performance Anal...inventionjournals
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.
BER Performance of MPSK and MQAM in 2x2 Almouti MIMO Systemsijistjournal
Almouti published the error performance of the 2x2 space-time transmit diversity scheme using BPSK. One of the key techniques employed for correcting such errors is the Quadrature amplitude modulation (QAM) because of its efficiency in power and bandwidth.. In this paper we explore the error performance of the 2x2 MIMO system using the Almouti space-time codes for higher order PSK and M-ary QAM. MATLAB was used to simulate the system; assuming slow fading Rayleigh channel and additive white Gaussian noise. The simulated performance curves were compared and evaluated with theoretical curves obtained using BER tool on the MATLAB by setting parameters for random generators. The results shows that the technique used do find a place in correcting error rates of QAM system of higher modulation schemes. The model can equally be used not only for the criteria of adaptive modulation but for a platform to design other modulation systems as well.
A new look on CSI imperfection in downlink NOMA systemsjournalBEEI
Observing that cooperative scheme benefits to non-orthogonal multiple access (NOMA) systems, we focus on system performance analysis of downlink. However, spectrum efficiency is still high priority to be addressed in existing systems and hence this paper presents full-duplex enabling in NOMA systems. Other challenge needs be considered related to channel state information (CSI). In particular, we derive closedform expressions of outage probability for such NOMA systems under the presence of CSI imperfection. Furthermore, to fully exploit practical environment, we provide system model associated with Nakagami-m fading. The Monte-Carlo simulations are conducted to verify the exactness of considered systems.
Effect on Channel Capacity of Multi-User MIMO System in Crowded AreaIJEEE
Multiple-Input Multiple-Output (MIMO) and Multi-User
MIMO (MU-MIMO) systems have been expected to
improve the channel capacity over a limited bandwidth of
existing networks.
Performance analysis of beam divergence propagation through rainwater and sno...journalBEEI
In the present work the future communication requirements need to fulfill with high data rate, FSO (free space optic) with it is tremendous potential is the solution. This research observed the effectiveness analysis of FSO systems by modifying one of the most important FSO parameters beam divergence, under the most affected weather attenuating condition Rainwater and snow pack. The simulation is obtained and analyzed under single channels CSRZ-FSO (carrier-suppressed return-to-zero/free space optical) systems having capacity of 40 Gbps between two transceivers with variable distance. The connection is presently under 5 meteorological turbulences (light rain, medium rain, wet snow, heavy rain and dry snow). The results show the heavy rain and dry snow have a very high attenuation carried out in terms of Q-factor. this result led us to conclude that small divergence offers significant performance improvement for FSO link and this performance decrease every time the beam divergence increase, Therefore, to build inexpensive and reliable transmission media, we go with new method that still in the experiment area called hybrid RF/FSO (radio frequency/free space optical) that compatible with atmospherically status.
Design and analysis of microstrip antenna with zig-zag feeder for wireless co...journalBEEI
This paper is presented a microstrip antenna with a zig-zag feeder for wireless communication, it has a wideband frequency spectrum (2-14) GHz. The proposed antenna is designed with a zig zag feed line which gave a wideband frequency and acceptable gain (7.448-5.928) dB, this antenna has zig zag slots printed in the ground plane on a lower side of the dielectric substrate, a certain form tuning stub is used to increase the matching between the feeder in the top layer of the substrate and ground plane in the bottom, this stub has an elliptical slot to performance matching input impedance with the feed line. The feeding technique used to feed this antenna is a strip feed line of 50 Ω. Different types of techniques are used to enhance the bandwidth of this antenna to get a wideband suitable for the requirements of the UWB antenna such as adjust the feed point position of the feed line with a tuning stub. All the radiation properties of the presented antenna are tested such as bandwidth, radiation pattern, and, gain.
Circularly polarized antenna array based on hybrid couplers for 5G devicesjournalBEEI
This paper depicts a wideband circularly polarized (CP) antenna for 5G devices. The antenna array has a 3D structure including four simple printed dipole elements with directional radiations, high gain, and high efficiency. It achieves a CP by using the sequential rotation (SR) feeding based on 90°-3dB hybrid couplers in the proposed feeding network. The antenna array bandwidth is wide, 26.7%, with an operating frequency band from 3.35 GHz to 4.35 GHz. The antenna achieves a high peak gain of 10.73 dBi and high efficiency of 93.75%. Besides, the antenna gain is stable over the operating bandwidth (BW). At the centre operating frequency of 3.75 GHz, the angle of circular polarization is 51°. The antenna is designed and fabricated on the Rogers 4003 C substrate. The measured S11 is well matching with the simulation results. With the above characteristics, the proposed antenna can be a suitable candidate for 5G devices.
Outage performance users located outside D2D coverage area in downlink cellul...journalBEEI
Device-to-device (D2D) communication has been proposed to employ the proximity between two devices to enhance the overall spectrum utilization of a crowded cellular network. With the help of geometric probability tools, this framework considers the performance of cellular users under spatial separation with the D2D pair is investigated. The measurement results and analytical expression of outage probability show that the proposed frameworks improve the outage performance at a high signal-tonoise ratio (SNR) at the base station. Results also interpret that the distances between nodes in the D2D-assisted network make slight impacts on the performance of the cellular user.
A Low Power High Bandwidth Four Quadrant Analog Multiplier in 32 NM CNFET Tec...VLSICS Design
Carbon Nanotube Field Effect Transistor (CNFET) is a promising new technology that overcomes several limitations of traditional silicon integrated circuit technology. In recent years, the potential of CNFET for analog circuit applications has been explored. This paper proposes a novel four quadrant analog multiplier design using CNFETs. The simulation based on 32nm CNFET technology shows that the proposed multiplier has very low harmonic distortion (<0.45%), large input range (±400mV), large bandwidth (~50GHz) and low power consumption (~247µW), while operating at a supply voltage of ±0.9V.
A New Approach to Linear Estimation Problem in Multiuser Massive MIMO SystemsRadita Apriana
A novel approach for solving linear estimation problem in multi-user massive MIMO systems is
proposed. In this approach, the difficulty of matrix inversion is attributed to the incomplete definition of the
dot product. The general definition of dot product implies that the columns of channel matrix are always
orthogonal whereas, in practice, they may be not. If the latter information can be incorporated into dot
product, then the unknowns can be directly computed from projections without inverting the channel
matrix. By doing so, the proposed method is able to achieve an exact solution with a 25% reduction in
computational complexity as compared to the QR method. Proposed method is stable, offers an extra
flexibility of computing any single unknown, and can be implemented in just twelve lines of code.
INVESTIGATING THE PERFORMANCE OF VARIOUS CHANNEL ESTIMATION TECHNIQUES FOR MI...ijmnct
This paper simulates and investigates the performance of four widely-used channel estimation techniques for MIMO-OFDM wireless communication systems; namely, super imposed pilot (SIP), comb-type, spacetime block coding (STBC), and space-frequency block coding (SFBC) techniques. The performance is evaluated through a number of MATLab simulations, where the bit-error rate (BER) and the mean square error (MSE) are estimated and compared for different levels of signal-to-noise ratio (SNR). The simulation results demonstrate that the comb-type channel estimation and the SIP techniques overwhelmed the performance of the STFC and STBC techniques in terms of both bit-error rate (BER) and mean square error (MSE).
Investigating the performance of various channel estimation techniques for mi...ijmnct
This paper simulates and investigates the performance of four widely-used channel estimation techniques for MIMO-OFDM wireless communication systems; namely, super imposed pilot (SIP), comb-type, spacetime block coding (STBC), and space-frequency block coding (SFBC) techniques. The performance is
evaluated through a number of MATLab simulations, where the bit-error rate (BER) and the mean square
error (MSE) are estimated and compared for different levels of signal-to-noise ratio (SNR). The simulation results demonstrate that the comb-type channel estimation and the SIP techniques overwhelmed the performance of the STFC and STBC techniques in terms of both bit-error rate (BER) and mean square error (MSE).
Wideband Branch Line Coupler with Open Circuit Coupled Lines IJECEIAES
This paper focuses on the design of a Wideband Branch Line Coupler by using open circuits coupled lines technique. The design is implemented by adding four open circuits coupled lines to the structure of the Conventional Branch Line Coupler. The proposed design of Wideband Branch Line C 3 z -3 orts. The prototype is fabricated and measured to validate the simulated results. A similar Wide Bandwidth is observed on simulation and measurement. The structure achieved a fractional bandwidth of 42.63%, and return loss of 21 dB compared to the Conventional Branch Line Coupler (BLC).
A Weighted Duality based Formulation of MIMO SystemsIJERA Editor
This work is based on the modeling and analysis of multiple-input multiple-output (MIMO) system in downlink communication system. We take into account a recent work on the ratio of quadratic forms to formulate the weight matrices of quadratic norm in a duality structure. This enables us to achieve exact solutions for MIMO system operating under Rayleigh fading channels. We outline couple of scenarios dependent on the structure of eigenvalues to investigate the system behavior. The results obtained are validated by means of Monte Carlo simulations.
Energy Efficiency of MIMO-OFDM Communication SystemIJERA Editor
With the ever increasing number of subscribers and their seemingly “greedy” demands for high-data-rate services, the next generation networks will have to provide global connectivity to ensure success. So the combination of multiple-input multiple-output (MIMO) signal processing with orthogonal frequency division multiplexing (OFDM) is regarded as a promising solution for enhancing the data rates of next-generation wireless communication systems operating in frequency-selective fading environments. Therefore hybrid architecture between terrestrial and satellite networks based on MIMO-OFDM with frequency reuse is employed here. However, this frequency reuse introduces severe co-channel interference (CCI) at the satellite end. To mitigate CCI, we propose an OFDM based adaptive beamformer implemented on-board the satellite with pilot reallocation at the transmitter side. The system performance is simulated by using the software MATLAB, the experimental result shows that the MIMO-OFDM communication system has better performance when compared.
Study on transmission over Nakagami-m fading channel for multiple access sche...TELKOMNIKA JOURNAL
In this paper, a downlink performance in non-orthogonal multiple access (NOMA) system is considered. With regard to different priority for two NOMA users, we exploit the closed-form expressions of outage probability over wireless fading channel following Nakagami-m fading. The fixed power allocation factor scheme is examined to reduce the complexity in computation regarding performance analysis. In our analysis, perfect successive interference cancellation (SIC) is applied in order to achieve perfect signal decoding operation. Simulation results show that the considered NOMA downlink scheme is affected by transmit SNR, power allocation factors, fading parameters.
An ultra wideband antenna for Ku band applicationsIJECEIAES
This paper presents a candidate ultra wideband antenna for Ku-band wireless communi- cations applications, analyzed and optimized by the finite element method (FEM). This three-dimensional modeling was realized and compared with published antennas for val- idate the performances of the proposed antenna. Its design is based on the insertion o fseveral symmetrical slots of different sizes on the ground plane of a mono-layer patch antenna to overcome the main limitation of the narrow bandwidth of patch antennas. The proposed antenna, made on an FR-4 epoxy mono-layer substrate with a defected ground plane (dielectric constant εr = 4,4, loss tangent tan δ = 0,02 and thickness hs = 1.6 mm). The simulated numerical results obtained are very satisfying; Bandwidth = 10.48 GHz from f1 = 9.34 GHz to f2 = 19.82 GHz, S11 = -34.17 dB, Voltage Stationary Wave Ratio VSWR = 1.04 , Gain = 6.27 dB.
A NOVEL ROBUST AND LOW-COMPLEXITY SPACETIME CODES FOR INDUSTRY 4.0 SYSTEMSijwmn
This paper proposes different robust and low-complexity space time codes which provide more reliability for industrial automation. An innovative synchronized uplink system configuration for an Industrial Environment is proposed. Mathematical framework for estimating the channel phase of each Slave Node (SN) is developed. Furthermore, the channel is practically estimated based on an innovative method using
parallel sequence spread spectrum (PSSS) implemented in Universal Software Radio Peripheral (USRP). The proposed space time codes are applied in the uplink of an industrial communication system where the channel is modelled using Quasi Deterministic Radio Channel Generator (Quadriga) which follows a geometry-based stochastic approach. Simulation results exposed that the proposed codes surpass Alamouti
code for Industrial Automation. The bit error rate (BER) performance demonstrates that the achieved coding gain for the proposed codes is higher than Alamouti code leading to more robust communication. Furthermore, a low complexity decoders based on minimum mean squared error (MMSE) and zero forcing (ZF) algorithms are designed at the receiver side. The proposed codes give a predominant execution against the state-of-the-art space time codes for Industry 4.0.
Compared to wireless deployment in areas with different environmentseIJECEIAES
In the mobile phone system, it is highly desirable to estimate the loss of the track not only to improve performance but also to achieve an accurate estimate of financial feasibility; the inaccurate estimate of track loss either leads to performance degradation or increased cost. Various models have been introduced to accurately estimate the path loss. One of these models is the Okomura / Hata model, which is recommended for estimating path loss in cellular systems that use micro cells. This system is suitable for use in a variety of environments. This study examines the comparison of path loss models for statistical analysis derived from experimental data collected in urban and suburban areas at frequencies of 150-1500 MHz’s The results of the measurements were used to develop path loss models in urban and suburban areas. The results showed that Pathloss increases in urban areas respectively.
AN ANALYTICAL ANALYSIS OF PATH LOSS MODELS FOR MOBILE CELLULAR WIRELESS COMMU...IJCI JOURNAL
The paper deals with the study based on the comparative analysis of radio propagation models for mobile cellular wireless communication of global system for mobile at frequencies 0.9 GHz and 1.8 GHz, respectively. The path loss propagation models are vital tool for planning the wireless network as well as
designed to predict path loss in a meticulous environment. Various propagation models: Free-space model, CCIR (ITU-R) model, Hata model, Ericson model, and Stanford University Interim (SUI) model have been studied and examined through analytically from the base station (BS) to mobile station (MS)
and vice versa followed by respective simulation performance evaluation by using Matlab simulator. The observed data is collected at the operating frequency of 0.9 GHz from various environments (high density region and low density region) using the spectrum analyzer and path loss comparison is shown for
different model.
In mmWave massive MIMO systems, the lens antenna array and beam selection by beamspace MIMO are employed to target the number of required RF chains reduced without obvious performance loss. For cost – effective, the number of RF chain is an allowable limitation, however, to obtain the near-optimal capacity efficiently, beam selection must require the exact information of the wide size of beamspace channel. Solution to this problem, in this paper we suggest analyzing whole beamspace based on maximal SINR. More specicfically, it is confirmed that the proposed beam selection algorithms achieve higher power efficiencies than a full system where all beams are employed.
Lantiq/Intel Contributions to G.fast at Scientific ConferencesLantiq
Rainer Strobel (Lantiq - An Intel Company), Michael Joham and Wolfgang Utschick presented several articles in academic conferences together with the Technical University of Munich. A conference recently held (June 8 to 12) was the ICC (International Conference on Communications) in London.
Title: Achievable Rates with Implementation Limitations for G.fast-based Hybrid Copper/Fiber Networks
Abstract - Hybrid copper/fiber networks bridge the gap between the fiber link and the customer by using copper wires over the last meters. This solution combines energy efficiency and low cost of the copper access network with high data rates of a fiber connection. However, the fiber to the distribution point (FTTdp) network must prove its ability to convey data at fiber speed over copper wire bundles under the spectral constraints of the copper access network. This work investigates achievable data rates of the FTTdp network. It provides an analysis of the sources of performance loss in a system implementation due to complexity limitations. The results indicate that optimized linear methods perform well on shorter lines, while nonlinear methods have advantages for long lines.
Due to increasing complexity, space and cost of communication network, the Electric Power Network has been considered a great option for the solution of all problems. Power line communications (PLC) term stands for the technologies for the data communication over the electrical power supply network. Existing power system is not designed for having data transfer. In this paper we have developed a simulation model of power-line for low voltage distribution network in home. Impulse response of the channel is generated in order to characterize the behavior of power line channel for high speed data communication purpose. To represent Multi-branch network mathematically, ABCD matrix parameters are used. Load mismatching is experimented on three parameters multiple loading, multi branch and different cable length and analysis is presented of its effect on impulse response. All the simulation work has been done using MATLAB.
BROADBAND POWER LINE COMMUNICATION: THE CHANNEL AND NOISE ANALYSIS FOR A POWE...IJCNCJournal
The scope for broadband powerline Communication is considered as a retrofit technology for wide geographical coverage wherever the human habitation exists. So during the last decade, it has drawn an enormous quantity of research work for improving communication performance and this system being standardized all over the world. The broadband power line Communication channel modelling is essential in the design of a reliable communications system. An analysis on the proposed channel model is conducted in this paper; also the paper studied the noises in Broadband powerline Communication network and its mathematical model. The channel Transfer function and Error Performance of Proposed powerline
communication System noise is evaluated with various digital modulation techniques Bit error rate (BER) and signal to noise ratio (SNR) curve by using simulation software. The results indicated that the noise analysis is effective for modelling the power line communication channel. Also, we have presented the various studies on the channel performance based on Orthogonal frequency-division Multiplexing (OFDM) systems for an efficient design of a Broadband Powerline Communication (BPLC) system.
Design and analysis of microstrip antenna with zig-zag feeder for wireless co...journalBEEI
This paper is presented a microstrip antenna with a zig-zag feeder for wireless communication, it has a wideband frequency spectrum (2-14) GHz. The proposed antenna is designed with a zig zag feed line which gave a wideband frequency and acceptable gain (7.448-5.928) dB, this antenna has zig zag slots printed in the ground plane on a lower side of the dielectric substrate, a certain form tuning stub is used to increase the matching between the feeder in the top layer of the substrate and ground plane in the bottom, this stub has an elliptical slot to performance matching input impedance with the feed line. The feeding technique used to feed this antenna is a strip feed line of 50 Ω. Different types of techniques are used to enhance the bandwidth of this antenna to get a wideband suitable for the requirements of the UWB antenna such as adjust the feed point position of the feed line with a tuning stub. All the radiation properties of the presented antenna are tested such as bandwidth, radiation pattern, and, gain.
Circularly polarized antenna array based on hybrid couplers for 5G devicesjournalBEEI
This paper depicts a wideband circularly polarized (CP) antenna for 5G devices. The antenna array has a 3D structure including four simple printed dipole elements with directional radiations, high gain, and high efficiency. It achieves a CP by using the sequential rotation (SR) feeding based on 90°-3dB hybrid couplers in the proposed feeding network. The antenna array bandwidth is wide, 26.7%, with an operating frequency band from 3.35 GHz to 4.35 GHz. The antenna achieves a high peak gain of 10.73 dBi and high efficiency of 93.75%. Besides, the antenna gain is stable over the operating bandwidth (BW). At the centre operating frequency of 3.75 GHz, the angle of circular polarization is 51°. The antenna is designed and fabricated on the Rogers 4003 C substrate. The measured S11 is well matching with the simulation results. With the above characteristics, the proposed antenna can be a suitable candidate for 5G devices.
Outage performance users located outside D2D coverage area in downlink cellul...journalBEEI
Device-to-device (D2D) communication has been proposed to employ the proximity between two devices to enhance the overall spectrum utilization of a crowded cellular network. With the help of geometric probability tools, this framework considers the performance of cellular users under spatial separation with the D2D pair is investigated. The measurement results and analytical expression of outage probability show that the proposed frameworks improve the outage performance at a high signal-tonoise ratio (SNR) at the base station. Results also interpret that the distances between nodes in the D2D-assisted network make slight impacts on the performance of the cellular user.
A Low Power High Bandwidth Four Quadrant Analog Multiplier in 32 NM CNFET Tec...VLSICS Design
Carbon Nanotube Field Effect Transistor (CNFET) is a promising new technology that overcomes several limitations of traditional silicon integrated circuit technology. In recent years, the potential of CNFET for analog circuit applications has been explored. This paper proposes a novel four quadrant analog multiplier design using CNFETs. The simulation based on 32nm CNFET technology shows that the proposed multiplier has very low harmonic distortion (<0.45%), large input range (±400mV), large bandwidth (~50GHz) and low power consumption (~247µW), while operating at a supply voltage of ±0.9V.
A New Approach to Linear Estimation Problem in Multiuser Massive MIMO SystemsRadita Apriana
A novel approach for solving linear estimation problem in multi-user massive MIMO systems is
proposed. In this approach, the difficulty of matrix inversion is attributed to the incomplete definition of the
dot product. The general definition of dot product implies that the columns of channel matrix are always
orthogonal whereas, in practice, they may be not. If the latter information can be incorporated into dot
product, then the unknowns can be directly computed from projections without inverting the channel
matrix. By doing so, the proposed method is able to achieve an exact solution with a 25% reduction in
computational complexity as compared to the QR method. Proposed method is stable, offers an extra
flexibility of computing any single unknown, and can be implemented in just twelve lines of code.
INVESTIGATING THE PERFORMANCE OF VARIOUS CHANNEL ESTIMATION TECHNIQUES FOR MI...ijmnct
This paper simulates and investigates the performance of four widely-used channel estimation techniques for MIMO-OFDM wireless communication systems; namely, super imposed pilot (SIP), comb-type, spacetime block coding (STBC), and space-frequency block coding (SFBC) techniques. The performance is evaluated through a number of MATLab simulations, where the bit-error rate (BER) and the mean square error (MSE) are estimated and compared for different levels of signal-to-noise ratio (SNR). The simulation results demonstrate that the comb-type channel estimation and the SIP techniques overwhelmed the performance of the STFC and STBC techniques in terms of both bit-error rate (BER) and mean square error (MSE).
Investigating the performance of various channel estimation techniques for mi...ijmnct
This paper simulates and investigates the performance of four widely-used channel estimation techniques for MIMO-OFDM wireless communication systems; namely, super imposed pilot (SIP), comb-type, spacetime block coding (STBC), and space-frequency block coding (SFBC) techniques. The performance is
evaluated through a number of MATLab simulations, where the bit-error rate (BER) and the mean square
error (MSE) are estimated and compared for different levels of signal-to-noise ratio (SNR). The simulation results demonstrate that the comb-type channel estimation and the SIP techniques overwhelmed the performance of the STFC and STBC techniques in terms of both bit-error rate (BER) and mean square error (MSE).
Wideband Branch Line Coupler with Open Circuit Coupled Lines IJECEIAES
This paper focuses on the design of a Wideband Branch Line Coupler by using open circuits coupled lines technique. The design is implemented by adding four open circuits coupled lines to the structure of the Conventional Branch Line Coupler. The proposed design of Wideband Branch Line C 3 z -3 orts. The prototype is fabricated and measured to validate the simulated results. A similar Wide Bandwidth is observed on simulation and measurement. The structure achieved a fractional bandwidth of 42.63%, and return loss of 21 dB compared to the Conventional Branch Line Coupler (BLC).
A Weighted Duality based Formulation of MIMO SystemsIJERA Editor
This work is based on the modeling and analysis of multiple-input multiple-output (MIMO) system in downlink communication system. We take into account a recent work on the ratio of quadratic forms to formulate the weight matrices of quadratic norm in a duality structure. This enables us to achieve exact solutions for MIMO system operating under Rayleigh fading channels. We outline couple of scenarios dependent on the structure of eigenvalues to investigate the system behavior. The results obtained are validated by means of Monte Carlo simulations.
Energy Efficiency of MIMO-OFDM Communication SystemIJERA Editor
With the ever increasing number of subscribers and their seemingly “greedy” demands for high-data-rate services, the next generation networks will have to provide global connectivity to ensure success. So the combination of multiple-input multiple-output (MIMO) signal processing with orthogonal frequency division multiplexing (OFDM) is regarded as a promising solution for enhancing the data rates of next-generation wireless communication systems operating in frequency-selective fading environments. Therefore hybrid architecture between terrestrial and satellite networks based on MIMO-OFDM with frequency reuse is employed here. However, this frequency reuse introduces severe co-channel interference (CCI) at the satellite end. To mitigate CCI, we propose an OFDM based adaptive beamformer implemented on-board the satellite with pilot reallocation at the transmitter side. The system performance is simulated by using the software MATLAB, the experimental result shows that the MIMO-OFDM communication system has better performance when compared.
Study on transmission over Nakagami-m fading channel for multiple access sche...TELKOMNIKA JOURNAL
In this paper, a downlink performance in non-orthogonal multiple access (NOMA) system is considered. With regard to different priority for two NOMA users, we exploit the closed-form expressions of outage probability over wireless fading channel following Nakagami-m fading. The fixed power allocation factor scheme is examined to reduce the complexity in computation regarding performance analysis. In our analysis, perfect successive interference cancellation (SIC) is applied in order to achieve perfect signal decoding operation. Simulation results show that the considered NOMA downlink scheme is affected by transmit SNR, power allocation factors, fading parameters.
An ultra wideband antenna for Ku band applicationsIJECEIAES
This paper presents a candidate ultra wideband antenna for Ku-band wireless communi- cations applications, analyzed and optimized by the finite element method (FEM). This three-dimensional modeling was realized and compared with published antennas for val- idate the performances of the proposed antenna. Its design is based on the insertion o fseveral symmetrical slots of different sizes on the ground plane of a mono-layer patch antenna to overcome the main limitation of the narrow bandwidth of patch antennas. The proposed antenna, made on an FR-4 epoxy mono-layer substrate with a defected ground plane (dielectric constant εr = 4,4, loss tangent tan δ = 0,02 and thickness hs = 1.6 mm). The simulated numerical results obtained are very satisfying; Bandwidth = 10.48 GHz from f1 = 9.34 GHz to f2 = 19.82 GHz, S11 = -34.17 dB, Voltage Stationary Wave Ratio VSWR = 1.04 , Gain = 6.27 dB.
A NOVEL ROBUST AND LOW-COMPLEXITY SPACETIME CODES FOR INDUSTRY 4.0 SYSTEMSijwmn
This paper proposes different robust and low-complexity space time codes which provide more reliability for industrial automation. An innovative synchronized uplink system configuration for an Industrial Environment is proposed. Mathematical framework for estimating the channel phase of each Slave Node (SN) is developed. Furthermore, the channel is practically estimated based on an innovative method using
parallel sequence spread spectrum (PSSS) implemented in Universal Software Radio Peripheral (USRP). The proposed space time codes are applied in the uplink of an industrial communication system where the channel is modelled using Quasi Deterministic Radio Channel Generator (Quadriga) which follows a geometry-based stochastic approach. Simulation results exposed that the proposed codes surpass Alamouti
code for Industrial Automation. The bit error rate (BER) performance demonstrates that the achieved coding gain for the proposed codes is higher than Alamouti code leading to more robust communication. Furthermore, a low complexity decoders based on minimum mean squared error (MMSE) and zero forcing (ZF) algorithms are designed at the receiver side. The proposed codes give a predominant execution against the state-of-the-art space time codes for Industry 4.0.
Compared to wireless deployment in areas with different environmentseIJECEIAES
In the mobile phone system, it is highly desirable to estimate the loss of the track not only to improve performance but also to achieve an accurate estimate of financial feasibility; the inaccurate estimate of track loss either leads to performance degradation or increased cost. Various models have been introduced to accurately estimate the path loss. One of these models is the Okomura / Hata model, which is recommended for estimating path loss in cellular systems that use micro cells. This system is suitable for use in a variety of environments. This study examines the comparison of path loss models for statistical analysis derived from experimental data collected in urban and suburban areas at frequencies of 150-1500 MHz’s The results of the measurements were used to develop path loss models in urban and suburban areas. The results showed that Pathloss increases in urban areas respectively.
AN ANALYTICAL ANALYSIS OF PATH LOSS MODELS FOR MOBILE CELLULAR WIRELESS COMMU...IJCI JOURNAL
The paper deals with the study based on the comparative analysis of radio propagation models for mobile cellular wireless communication of global system for mobile at frequencies 0.9 GHz and 1.8 GHz, respectively. The path loss propagation models are vital tool for planning the wireless network as well as
designed to predict path loss in a meticulous environment. Various propagation models: Free-space model, CCIR (ITU-R) model, Hata model, Ericson model, and Stanford University Interim (SUI) model have been studied and examined through analytically from the base station (BS) to mobile station (MS)
and vice versa followed by respective simulation performance evaluation by using Matlab simulator. The observed data is collected at the operating frequency of 0.9 GHz from various environments (high density region and low density region) using the spectrum analyzer and path loss comparison is shown for
different model.
In mmWave massive MIMO systems, the lens antenna array and beam selection by beamspace MIMO are employed to target the number of required RF chains reduced without obvious performance loss. For cost – effective, the number of RF chain is an allowable limitation, however, to obtain the near-optimal capacity efficiently, beam selection must require the exact information of the wide size of beamspace channel. Solution to this problem, in this paper we suggest analyzing whole beamspace based on maximal SINR. More specicfically, it is confirmed that the proposed beam selection algorithms achieve higher power efficiencies than a full system where all beams are employed.
Lantiq/Intel Contributions to G.fast at Scientific ConferencesLantiq
Rainer Strobel (Lantiq - An Intel Company), Michael Joham and Wolfgang Utschick presented several articles in academic conferences together with the Technical University of Munich. A conference recently held (June 8 to 12) was the ICC (International Conference on Communications) in London.
Title: Achievable Rates with Implementation Limitations for G.fast-based Hybrid Copper/Fiber Networks
Abstract - Hybrid copper/fiber networks bridge the gap between the fiber link and the customer by using copper wires over the last meters. This solution combines energy efficiency and low cost of the copper access network with high data rates of a fiber connection. However, the fiber to the distribution point (FTTdp) network must prove its ability to convey data at fiber speed over copper wire bundles under the spectral constraints of the copper access network. This work investigates achievable data rates of the FTTdp network. It provides an analysis of the sources of performance loss in a system implementation due to complexity limitations. The results indicate that optimized linear methods perform well on shorter lines, while nonlinear methods have advantages for long lines.
Due to increasing complexity, space and cost of communication network, the Electric Power Network has been considered a great option for the solution of all problems. Power line communications (PLC) term stands for the technologies for the data communication over the electrical power supply network. Existing power system is not designed for having data transfer. In this paper we have developed a simulation model of power-line for low voltage distribution network in home. Impulse response of the channel is generated in order to characterize the behavior of power line channel for high speed data communication purpose. To represent Multi-branch network mathematically, ABCD matrix parameters are used. Load mismatching is experimented on three parameters multiple loading, multi branch and different cable length and analysis is presented of its effect on impulse response. All the simulation work has been done using MATLAB.
BROADBAND POWER LINE COMMUNICATION: THE CHANNEL AND NOISE ANALYSIS FOR A POWE...IJCNCJournal
The scope for broadband powerline Communication is considered as a retrofit technology for wide geographical coverage wherever the human habitation exists. So during the last decade, it has drawn an enormous quantity of research work for improving communication performance and this system being standardized all over the world. The broadband power line Communication channel modelling is essential in the design of a reliable communications system. An analysis on the proposed channel model is conducted in this paper; also the paper studied the noises in Broadband powerline Communication network and its mathematical model. The channel Transfer function and Error Performance of Proposed powerline
communication System noise is evaluated with various digital modulation techniques Bit error rate (BER) and signal to noise ratio (SNR) curve by using simulation software. The results indicated that the noise analysis is effective for modelling the power line communication channel. Also, we have presented the various studies on the channel performance based on Orthogonal frequency-division Multiplexing (OFDM) systems for an efficient design of a Broadband Powerline Communication (BPLC) system.
Accurate modeling of cables is important to study the behavior of high frequency disturbances in power converter systems. This paper reviews and compares two popular methodologies to model energy cables – an improved per unit length parameters based model and a Laplace SPICE element based model. The two models presented take into account the frequency dependence of the parameters of the cable. A ladder network is used for this purpose in the per unit length based model. The Laplace SPICE element model is generated from from a rational function approximation for the admittance parameters that are frequency dependant. The rational function approximation is obtained using a well known vector fitting algorithm. The time and frequency domain solutions of a two wire energy cable, obtained from the two models, agree well.
Magnetic resonance coupling for 5G WPT applicationsjournalBEEI
Inductive Wireless Power Transfer (IWPT) is the most popular and common technology for the resonance coupling power transfer. However, in 2007 it has experimentally demonstrated by a research group from Massachusets Institute of Technology (MIT) that WPT can be improved by using Magnetic Resonance Coupling Wireless Power Transfer (MRC WPT) in terms of the coupling distance and efficiency. Furthermore, by exploiting the unused, high-frequency mm-wave band which are ranging from 3~300 GHz frequency band, the next 5G generations of wireless networks will be able to support a higher number of devices with the increasing data rate, higher energy efficiency and also compatible with the previous technology. In this work, a square planar inductor with the dimension of 6.1 x 6.1 mm is designed, and the resonators have the same self-resonance frequency at 14 GHz. The coil resonators have been laid on Silicon and Oxide substrate to reduce the loss in the design. From the CST software simulation and the analytical model in MATLAB software, it has been shown that the MRC WPT design has improved the performance of IWPT design by 40% power transfer efficiency. MRC WPT design also has larger H-Field value which is 705.5 A/m, as compared to the IWPT design which has only 285.6 A/m when both Transmitter(Tx) and Reciever(RX) is at 0.3 mm coupling distance.
Scedasticity descriptor of terrestrial wireless communications channels for m...IJECEIAES
Fifth-generation (5G) wireless systems increased the bandwidth, improved the speed, and shortened the latency of communications systems. Various channel models are developed to study 5G. These channel models reproduce the stochastic properties of multiple-input multiple-output (MIMO) antennas by generating wireless multipath components (MPCs). The MPCs with similar properties in delay, angles of departure, and angles of arrival form clusters. The multipaths and multipath clusters serve as datasets to understand the properties of 5G. These datasets generated by the Cooperation in Science and Technology 2100 (COST 2100), International Mobile Telecommunications-2020 (IMT-2020), Quasi Deterministic Radio Channel Generator (QuaDRiGa), and Wireless World Initiative New Radio II (WINNER II) channel models are tested for their homoscedasticity based on Johansen's procedure. Results show that the COST 2100, QuaDRiGa, and WINNER II datasets are heteroscedastic, while the IMT-2020 dataset is homoscedastic.
A compact triband microstrip antenna utilizing hexagonal CSRR for wireless co...journalBEEI
In this paper, a compact triband printed antenna with hexagonal complementary split-ring resonators (CSRRs) for 4G applications is proposed. The proposed multiband antenna is comprised of a rectangular patch antenna on the top plane, while on the ground plane, hexagonal CSRRs are etched for size miniaturization (at the lower bands) and multiband generation. Another effect of the CSRR is the shifting of the initial resonance of the patch antenna from 5.17 GHz to the higher band of 6.18 GHz. The triband of 180 MHz 2.4~2.59, 150 MHz 2.79~2.94 and 420 MHz 6.04~6.46 GHz bands acquired can cover WLAN/Wi-Fi and WiMAX operating bands adequately. This can be achieved by choosing the optimal size and position of the CSRR on the ground plane carefully. The design occupies a total size of 45 x 45 mm2 using the low-cost FR-4 substrate. Good agreements are obtained between the measured results and the simulated, which are discussed and presented.
A new configuration of a printed diplexer designed for DCS and ISM bandsTELKOMNIKA JOURNAL
This work presents a new study on the design of a microstrip diplexer configuration optimized and validated for ISM and DCS frequency bands. The achieved structure is based on microstrip technology, the goal was to design two printed bandpass filters one for ISM band and the other one for DCS frequency band.The two microstrip filters are associated by using a T-junction which permits to validate a diplexer in the frequency bands DCS-Band receiver [1.74–2 GHz] and ISM-Band transmitter [2.3–2.55 GHz]. The whole size of the final circuit is 130x50 mm2. After the validation of the proposed diplexer into simulation we have fabricated and tested it by using VNA which permits to have a good agremment between simulation and measurements.
Six-port Interferometer for W-band Transceivers: Design and CharacterizationIJECEIAES
The study has presented an extensive analysis of an integrated millimeter wave six-port interferometer, operating over a 10 GHz band, from 80 to 90 GHz. It has covered both semi-unlicensed point-to-point links (81-86 GHz), and imaging sensor system frequencies (above 85 GHz). An in-house process is used to fabricate miniaturized hybrid millimeter wave integrated circuits on a very thin ceramic substrate. Two-port S-parameter measurements are performed on a minimum number of circuits integrated on the same die, exploiting the circuit’s physical symmetry and chosen to collect enough data for full-port characterization. Based on these measurements on an integrated prototype, a six-port circuit computer model implemented and advanced system simulations performed for circuit analysis. Interferometer performances evaluated using several methods: analysis of harmonic balance, qi points’, homodyne quadrature demodulation, and error vector modulation (EVM). The analysis showed that this circuit can directly perform, without any calibration, the demodulation of various PSK and QAM signals over the 10 GHz band, with very good results.
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.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
Learn about:
• The Future of Testing: How AI is shifting testing towards verification, analysis, and higher-level skills, while reducing repetitive tasks.
• Test Automation: How AI-powered test case generation, optimization, and self-healing tests are making testing more efficient and effective.
• Visual Testing: Explore the emerging capabilities of AI in visual testing and how it's set to revolutionize UI verification.
• Inflectra's AI Solutions: See demonstrations of Inflectra's cutting-edge AI tools like the ChatGPT plugin and Azure Open AI platform, designed to streamline your testing process.
Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Wideband Modeling of Twisted-Pair Cables for MIMO Applications
1. Technische Universität München
Wideband Modeling of Twisted-Pair Cables for MIMO Appli-
cations
Globecom 2013 - Symposium on Selected Areas in Communications (GC13 SAC)
Rainer Strobel, Reinhard Stolle, and Wolfgang Utschick
c 2013 IEEE. Personal use of this material is permitted. However, permission to reprint/re-
publish this material for advertising or promotional purposes or for creating new collective
works for resale or redistribution to servers or lists, or to reuse any copyrighted component
of this work in other works must be obtained from the IEEE.
Department of Electrical Engineering and Information Technology
Associate Institute for Signal Processing
Univ.-Prof. Dr.-Ing. Wolfgang Utschick
2. Wideband Modeling of Twisted-Pair Cables for
MIMO Applications
Rainer Strobel∗‡
, Reinhard Stolle†
, Wolfgang Utschick∗
∗Associate Institute for Signal Processing, Technische Universität München, 80333 München
{rainer.strobel,utschick}@tum.de
†Hochschule Augsburg, 86161 Augsburg, reinhard.stolle@hs-augsburg.de
‡Lantiq Deutschland GmbH, 85579 Neubiberg, rainer.strobel@lantiq.com
Abstract—Recent trends in broadband access technology
show the demand to extend the used frequency bands up
to hundreds of MHz. Access cables are not built for such
high frequencies, and measurements of access cables in
this frequency range show a significant change of the cable
characteristics compared to low frequencies.
The novel modeling approach presented here is designed
to be used for evaluation of transmission technologies for
fiber-copper hybrid networks, so called FTTdp (Fiber To The
distribution point), which enables service providers to serve
customers with data rates in the GBit/s range without the
requirement to install fiber to the home.
I. INTRODUCTION
As the bandwidth requirements increase, a different
network topology is used for the fourth generation of
broadband access [1], than in classical ADSL [2] and
VDSL [3] networks. A fiber-copper hybrid network al-
lows the delivery of data rates in the GBit/s range, while
the deployment costs are still low compared to pure
fiber networks. The fourth generation network consists
of distribution points, which are connected to the central
office via fiber. The distribution points serve a small
number of customers over short distances of copper
wires.
With increasing frequency, the idealized modeling ap-
proach which was used to design ADSL and VDSL
broadband access, e. g. [4] or [5], can no longer be used
and a more accurate characterization is required for the
system design.
Therefore, a new modeling approach is proposed in
this paper, which makes it possible to describe the
physical effects of copper access networks for MIMO
transmission at frequencies up to 300 MHz. The model
is furthermore formulated such that it can be fitted to
measurement data of real cables.
II. RECENT WORK
The work on channel models for the fourth generation
broadband access networks has recently been started
with measurements of cables under the conditions de-
fined for a FTTdp network and comparison of the results
with previously used models.
A. Differential Single Line Models
Channel models for evaluation of data transmission
on twisted pair cables are mainly based on a character-
ization of the differential mode of a single twisted pair.
The models describe the primary line constants, serial
resistance R, serial inductance L, parallel capacitance C
and parallel conductance G per unit length.
Popular models for access cables are the ETSI model
[4] used for VDSL up to 30 MHz or the recently intro-
duced ITU model [6] for the approximation of differen-
tial mode transfer functions up to 300 MHz.
The secondary line constants, line impedance Z0(ω)
and propagation constant γ(ω) are given by
Z0(ω) =
R + jωL
G + jωC
(1)
and
γ(ω) = (R + jωL)(G + jωC) (2)
as a function of frequency ω = 2π f and the primary line
constants.
The matrix description of a transmission line of length
l is then given by
U(0)
I(0)
=
cosh(γl) Z0 sinh(γl)
1
Z0
sinh(γl) cosh(γl)
·
U(l)
I(l)
, (3)
the so called telegrapher’s equations [7], which describe
the voltage U and current I at the line input as a function
of voltage and current at the line output.
Due to the high bandwidth which is covered by the
models, the primary line constants are no longer con-
stant over frequency. Therefore, models like [4] or [6]
approximate them with nonlinear functions.
Crosstalk is modeled in [4] as noise with a specific
noise spectrum that depends on the cable type and the
number of lines in a binder.
B. Crosstalk Models
For the analysis of crosstalk cancelation for VDSL [8],
this model is no longer appropriate and therefore, MIMO
models have been introduced.
The ATIS MIMO model [5] is based on a direct channel
model description Hchannel( f ) , e. g. on the ETSI model.
3. Additionally, crosstalk coupling paths HFEXT( f ) accord-
ing to
HFEXT ik( f ) = |Hchannel( f )| f ejϕ( f )
κ lcoupling10xdB ik/20
(4)
are added. Additional parameters are a random phase
term ϕ( f ), the scaling constant κ, the coupling length
lcoupling and a random coupling strength matrix XdB
which has been created based on measurements.
This model does not give a complete MIMO descrip-
tion of a cable binder, because couplings between the
channels are only described by far-end crosstalk transfer
functions. Therefore, it is not feasible to cascade channel
matrices from the ATIS model.
Several approaches, e. g. [9] have been made to create
cable models which are closer to the physical charac-
teristics of a cable binder and characterize not only the
differential mode, but also the phantom mode of a cable
binder [10].
C. Cable Measurements at High Frequencies
Measurement data which is presented in this paper
is based on results from a recent study at Deutsche
Telekom [11] and fits to measurement data from other
measurement campaigns, e. g. [12], [13] and [14]. The
data shows effects which are not covered by the models
which are currently in use.
Fig. 1 compares measurements of a short cable binder
of a Deutsche Telekom access cable [11] (10-pair cable
of 30 m length) with the corresponding results from
the ETSI model. The measured direct channel shows a
significantly higher attenuation at high frequencies than
is predicted by the ETSI model [4]. This behavior is also
observed in the measurement data of [15]. Fig. 1 also
shows a single dominant crosstalk coupling, which is
the crosstalk between the two pairs of a quad cable. It
dominates the crosstalk power sum in the measurement.
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
0 50 100 150 200 250 300
transferfunction/dB
f/MHz
Direct channel measured
FEXT measured
FEXT power sum measured
Direct channel ETSI
FEXT power sum ETSI
Fig. 1. Transfer function of direct line and crosstalkers of 30m line
In the ATIS model, the crosstalk coupling strength
is a function of frequency with the proportionality
|HFEXT( f )|2 ∼ |Hchannel( f,l)|2 · f2. Some of the avail-
able measurement data, e. g. Fig, 1, [14] or [16] in-
dicates that this does not hold for high frequencies
in quad cables where sometimes the proportionality
|HFEXT,dualslope( f )|2 ∼ |Hchannel( f,l)|2 · f4 is observed.
The single line models [4] and [6] and the MIMO model
[5] do not distinguish between twisted pair and quad
cables and therefore neglect this effect.
In the statistical model of [5], the direct channel char-
acteristics are assumed to be constant within the cable
binder and therefore modeled in a deterministic manner,
while the available measurement data indicates that the
cable characteristics have a random variance over the
cable length and over the different pairs in a binder. In
a time domain reflexion measurement of an open-ended
cable of 20 m length, as shown in Fig. 2, it can be seen
that a significant amount of energy is reflected at a length
of less than 20 m. This indicates that the direct channel
characteristics like line impedance Z0 are not constant
over the cable length.
-0.05
0
0.05
0.1
0.15
0 5 10 15 20 25 30
0 20 40 60 80 100 120 140
impulseresponse
l/m
t/ns
Impulse response 50MHz
Impulse response 300MHz
Fig. 2. Reflexion of a 20 m transmission line in time domain
Based on these observations, a channel model for
evaluation of FTTdp networks preferably considers a
cascade of cable binder segments which may include
random variations of the channel characteristics and can
be fitted to measurement data.
III. TOPOLOGY MODEL
The telephony cable network consists of multiple sec-
tions. In many cases, different cable types are used in
different sections. The proposed topology model uses
three sections as shown in Fig. 3.
1) A drop wire section, running from the distribution
point to the buildings,
2) an in-building section connecting the drop wire
with the individual subscribers homes,
3) an in-home part with a single quad or pair, possibly
with bridged taps and similar imperfections.
For the topology model, each section is described by a
matrix Asec such that the sections can be cascaded. This
approach requires an appropriate description for small
cable binder segments.
4. ...
...
...
...
...
...
drop wire in house in home
Asec 1 Asec 2 Asec 3
Fig. 3. Telephony network topology
A. Multiconductor Models
Cascades of circuit elements are widely used in high
frequency circuit design. In twoport theory, each element
is described by a matrix. A chain matrix describes the de-
pendency between input voltage and current and output
voltage and current and a cascade of circuit elements can
be calculated by the product of the chain matrices of the
individual circuit elements.
To extend the chain matrix description to a cable
binder, the multiconductor transmission line theory was
introduced in [17]. The multiconductor chain matrix A
is defined as
u(0)
i(0)
=
A11 A12
A21 A22
·
u(l)
i(l)
(5)
and describes the relation from an input voltage vector
u(0) and an input current vector i(0) to the output
voltage vector u(l) and output current vector i(l).
The overall chain matrix Aall of multiple cable binder
sections Asec i is given by the product of the individual
section matrices, as shown in
Aall = ∏
i
Asec i. (6)
If the models from Sec. II-A are used in a multiconduc-
tor description, they describe only the diagonal elements
of the block matrices A11, A12, A21 and A22. The voltages
are defined as differential voltages between the wires of
each pair. Fig. 4 shows the circuit corresponding to a
differential element of the multiconductor twisted pair
cable binder with two pairs in differential mode.
l l+dl
u1(l)
i1(l)
u2(l)
i2(l)
u1(l + dl)
i1(l + dl)
u2(l + dl)
i2(l + dl)
Fig. 4. Cable binder segment with multiple uncoupled differential
lines
The crosstalk models as described in Section II-B do
not fit to the chain matrix description because these
models describe crosstalk transfer functions, only. Fur-
thermore, limiting the models to differential mode is
not sufficient to cover some effects of the measurement
data, for example the frequency dependency of far-end
crosstalk.
Therefore, the proposed model does not only describe
the differential modes of the pairs, but describes voltage
and current of the single wires with respect to a common
reference potential.
This is hereinafter called single-ended description.
The methods for conversion from a single-ended chain
matrix to the corresponding differential modes, which
are of interest for signal transmission, are described in
[18] and in [19].
B. Single-Ended Geometry Model
Alternatively to [9], where one of the wires is used as
reference for the single-ended description, the proposed
topology model uses a separate ground plane as refer-
ence for all wires (Fig. 5). For shielded cables, the shield
may be used as reference potential.
dik
hi
2ri
k i
(a) Single segment (b) Twisted quad
Fig. 5. Geometrical model of quad cable
The following derivations are based on results from
multiconductor transmission line theory, which can be
found in [20].
From the geometry as shown in Fig. 5(a), the self-
inductance and mutual inductance of a short segment are
given by Eq. (7) [20], which defines the inductance ma-
trix L. The following equations hold for the assumptions
5. of homogeneous media between the conductors and that
they are widely separated in space.
The self inductance lii of wire i depends on the dis-
tance hi between the wire and the ground plane and
on the radius ri of the wire. The mutual inductance lik
between wires i and k also depends on the distance dik
between the wires
lik =
µ
2π log 2hi
ri
for i = k
µ
4π log 1 + 4hihk
d2
ik
for i = k
. (7)
With known permittivity ε and permeability µ of the
media between the conductors, the capacitance matrix C
is obtained by matrix inversion [20]
C = µεL−1
(8)
from the inductance matrix.
With the conductivity σ of the insulation medium, the
conductance matrix G is given by
G =
σ
ε
C, (9)
as shown in [20].
Finally the resistance matrix R is calculated from the
wire conductivity σwire, the permeability µwire and the
wire radius ri.
According to [21], the skin effect can be approximated
by the skin depth δ by
δ =
1
π f µwireσwire
. (10)
The resistance matrix R is then obtained by
rik =
1
2πσriδ for i = k
0 for i = k
(11)
which is a diagonal matrix [20].
To calculate the secondary line constant matrices γ and
Z0 from the serial impedance matrix Zs = R( f ) + jωL
and the parallel admittance matrix Yp = G + jωC,
diagonalization of the product matrix Yp · Zs is needed.
Eigenvalue decomposition on the product matrix, as
proposed in [20], gives the definition
YpZs = Tlγ2
T−1
l . (12)
Then, γ is a diagonal matrix describing transmission
term and Z0 is the line impedance matrix defined by
Z0 = ZsTlγ−1
T−1
l (13)
and the corresponding admittance matrix Y0 is given by
Y0 = Tlγ−1
T−1
l Yp. (14)
The chain matrix Aseg of a cable binder segment of
finite length l is then
Aseg =
Z0Tl cosh (γl) T−1
l Y0 Z0Tl sinh (γl) T−1
l
Tl sinh (γl) T−1
l Y0 Tl cosh (γl) T−1
l
.
(15)
Eq. (15) is equivalent to the integration over the dif-
ferential elements as shown in Fig. 6. Therefore, the
geometry must not change over the integration length
l, which means that it is only allowed to integrate over
a fraction of the twist-length of the twisted pair cable.
On a cable with perfect twisted pair geometry,
crosstalk coupling would be much weaker than it is
observed in real cables. Most of the crosstalk is caused
by imperfections in the cable geometry [9]. In a cable
model, this requires a random imperfection component
and the statistics of the imperfection must be such that
the crosstalk statistics match the measurement data.
If the statistical model is based on primary line con-
stants, as described in the next section, the length l
of each segment is chosen such that the primary line
constants are approximately constant over the segment
length.
C. Statistical Model for Primary Line Constants
A major drawback of geometrical models besides com-
putational complexity is the fact that relevant parameters
to describe geometry imperfections and characteristics of
the insulation material are difficult to measure.
The proposed model is built from short segments
according to Eq. (15). Each segment is a cascade of
differential binder elements as shown in Fig. 6.
The primary line constants can be obtained by elec-
trical measurements. Therefore, the statistical model is
based on statistical characteristics of the primary line
constants.
l l+dl
u1(l)
i1(l)
u2(l)
u3(l)
u4(l)
i2(l)
i3(l)
i4(l)
u1(l + dl)
i1(l + dl)
u2(l + dl)
u3(l + dl)
u4(l + dl)
i2(l + dl)
i3(l + dl)
i4(l + dl)
Fig. 6. Cable binder segment for common mode model
However, the primary line constants cannot be de-
scribed independently. To match the physical properties
of an existing cable, some dependencies must be taken
into account.
1) Binder Geometry: The model in [9] describes random
imperfections in cable geometry. The proposed model is
based on primary line constants, but it uses some knowl-
edge on the cable binder geometry. Crosstalk coupling
strength does not only depend on random imperfections
of the twisting of each pair or quad, but also on the
distance between the pairs as shown in Eq. (7) and on
the twist lengths of the individual pairs.
To consider this in a statistical model, it is based on
random positions of the wires in space, similar to the
single quad shown in Fig. 5, where an individual twist
6. length is assigned to each of them. The random variation
of coupling inductance lik between lines i and k is then
scaled with respect to the distance dik between the pairs
or quads.
This dependency follows from the geometric model
and can be verified by measurement data. It allows to
scale the model to arbitrary cable binder sizes, which
is not possible for the ATIS model, where the statistics
match only with the measured 100-pair binder.
2) Correlations over Length: The random values of pri-
mary line constants are correlated over the length of
the cable binder. The frequency dependence of crosstalk
transfer functions observed in measurements, e. g. in Fig.
1 depends on the correlation over cable length.
If correlation over cable length is neglected, the re-
sulting crosstalk transfer functions do not match the
measurement data, as the results in [9] show, where
no correlations were considered. Furthermore, the cor-
relation over length is required to guarantee that the
resulting transfer functions are independent of the length
of the cable binder segments used in the model as long
as they are sufficiently short. With known correlation
length of the cable, the model segment length can then
be selected with respect to the sampling theorem. As the
correlation length in the available measurement data is
in the range of meters, this gives a major computational
advantage in comparison to the geometric model.
3) Homogeneity: Based on the random inductance ma-
trix L, conductance and capacitance matrices G and
C cannot be created independently. As shown in [17]
and [20], Eq. (8) and Eq. (9) hold for the case that the
insulation medium between the wires is homogeneous.
The real cable differs from this dependency between
due to inhomogeneity of the insulation medium, but the
dependency still holds approximately.
4) Causality: Furthermore, there is a dependency be-
tween resistance R(ω) and inductance L(ω) over fre-
quency as well as between capacitance C(ω) and con-
ductance G(ω). The dependency is given by the require-
ment that each segment transfer function must be causal.
According to [22], this can be achieved by applying the
Hilbert transform. Therefore, the primary line constants
are divided into a frequency-dependent component and
a frequency-independent component. For example, the
resistance R(ω) is divided into ˆR(ω) and ∆R, where
R(ω) = ˆR(ω) + ∆R.
Then,
R(ω) − ∆R =
1
π
∞
−∞
x(L(ω) − ∆L)
ω − x
dx (16)
holds for the serial impedance R + jωL.
The frequency dependency of the primary line con-
stants originates from the skin effect as described in
Eq. (10) and (11). The resulting resistance matrix R is a
diagonal matrix and therefore, Eq. (16) is only applied to
the diagonal elements of the inductance matrix L, while
the off-diagonal elements are constant over frequency.
D. Proposed Modeling Steps
The results shown in the next section are based on
following modeling steps, which are one method to
fulfill the mentioned requirements.
1) In a first step, Eq. (7) is evaluated to calculate
the inductance matrix with respect to perfect cable
geometry.
2) Random variance is added to the inductance matrix
using correlated Gaussian random values.
3) The resistance matrix is calculated based on Eq. (10)
and Eq. (11) with respect to cable characteristics.
4) Based on the resistance matrix, the self-inductance
frequency dependency is corrected using Eq. (16).
5) Capacitance and conductance matrices are calcu-
lated using matrix inversion (Eq. (8) and Eq. (9)).
6) Evaluation of Eq. (12) to (15) gives the segment
chain matrices, which are cascaded.
Medium inhomogeneities and radiation loss are ig-
nored in the results. The loss of the insulation medium
of the reference cable is too small to be measured with
sufficient precision and is therefore also ignored.
IV. MODEL RESULTS
As one example, the numerical results for the topology
model of a 30 m access cable from Deutsche Telekom [11]
are shown. The statistics of the inductance matrix L has
been chosen such that some reference measures match
the real cable. They are the crosstalk power sum over
frequency, the crosstalk coupling strength cumulative
density function and the average direct channel transfer
function.
0
0.2
0.4
0.6
0.8
1
-60 -50 -40 -30 -20 -10 0 10
F(XdB)
Crosstalk Coupling/dB
Measurement Data
Topology Model
ATIS Model
Fig. 7. Cumulative density functions of intra-quad crosstalk coupling
strength XdB.
Fig. 7 shows the cumulative density functions F(XdB)
of the crosstalk coupling strength in dB XdB of the
ATIS model in comparison to the average crosstalk
coupling strength from the 10-pair Deutsche Telekom
cable and the topology model using the parameters of
the Deutsche Telekom access cable.
7. The cumulative density functions show that the
crosstalk coupling strength of the measured cable does
not match the ATIS model [5] whereas the topology
model yields a good fit of the crosstalk statistics for
small cable binders. The crosstalk coupling strength XdB
describes the frequency independent part of the crosstalk
transfer functions, as shown in Eq. (4).
For the frequency dependency of the crosstalk, a
comparison of the crosstalk transfer functions and the
crosstalk power sum is shown in Fig. 8.
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
0 50 100 150 200 250 300
transferfunction/dB
f/MHz
Direct channel model
FEXT model
FEXT power sum model
Direct channel ETSI
FEXT power sum ETSI
Fig. 8. Direct channel and crosstalk transfer functions of topology
model for 30m Deutsche Telekom access cable.
In both, the measurement data of the cable in Fig. 1
and the topology model in Fig. 8, the crosstalk trans-
fer functions show a random frequency dependency.
At higher frequencies, the direct channel attenuation
is higher than predicted by the ETSI model. The in-
quad crosstalk is signficantly stronger than the intra-
quad crosstalkers and does not match the prediction
of the ETSI model. It even exceeds the direct channel
transfer function at higher frequencies. This behavior is
also seen in the measurement data shown in Fig. 1.
V. CONCLUSION
The proposed model provides a tool to analyze the
telephony network for FTTdp applications.
Statistical modeling with respect to the physical char-
acteristics guarantees that the resulting channel descrip-
tion corresponds to the properties of existing cable
binders. With more measurement data available, the
statistical model of the random coupling elements can
be refined.
The presented model already gives promising results
for FTTdp frequency domain and time domain simula-
tions.
ACKNOWLEDGMENT
The authors would like to thank Peter Muggenthaler
from Deutsche Telekom for providing measurement data
and information about network topologies, as well as
discussions about physical characteristics of twisted pair
cable binders. This valuable information has been used
as basis for the cable model.
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