Wideband Parameters Research Articles

Wideband Synthetic-Aperture Millimeter-Wave Spatial-Channel Reference System With Traceable Uncertainty Framework

This paper describes a wideband synthetic-aperture system and the associated Fourier processing for generating high-resolution spatial and temporal estimates of the signal propagation environment in wireless communication channels at millimeter-wave frequencies. We describe how to configure the synthetic aperture system for high angular resolution by sampling the progression of signal phase across a large planar area in space. We also show how to synthesize discrete measurements of the channel frequency response taken sequentially over a wide bandwidth to create power delay profiles (PDPs) in specified angular directions with high delay resolution. We provide a rigorous uncertainty analysis that can be made metrologically traceable to fundamental physical standards. This uncertainty framework can propagate the errors inherent in the measured signals through to the final channel estimates and derived parameters such as root-mean-square delay or angular spread. We illustrate use of the system in conjunction with two different analysis tools to extract both narrowband and wideband parameter estimates from the synthetic aperture, allowing its use as a stand-alone channel sounder or as a tool for verifying the performance of wireless devices.

The Detailed Representation and Computation of the Traction Network and its Application to the Transient Analysis in Electrified Railways

This paper intends to derive a detailed representation and attain a suitable computation method for the traction network. The transient analysis of the lossy multiconductor transmission lines (MTLs) is performed considering the electromagnetic characteristics of the rail track, which accounts for the frequency‐dependent and distributed nature of the line parameters over the entire frequency range for the traction network. Due to the practical difficulty in wideband parameter determination and the complex layout for the traction power supply system, the model implemented has been validated by comparison to several field tests that are carried out on a real high speed railway line for the purpose of identifying possible power quality problem. The good high representation of the frequency‐dependent parameter and the numerical solution will provide a reliable method for the transient analysis of the electrified railway. Afterwards, the transient calculation using vector fitting and modal decomposition is presented to evaluate how the emission is propagating along the MTLs of the electrified railways. Performing detailed and suitable analysis is necessary to determine the overvoltage conditions during the transients. The outcome of the analysis could be beneficial for the transient protection study in the electrified railway system. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Effects of Otosclerosis on Middle Ear Function Assessed With Wideband Absorbance and Absorbed Power.

Wideband absorbance and absorbed power were evaluated in a group of subjects with surgically confirmed otosclerosis (Oto group), mean age 51.6 years. This is the first use of absorbed power in the assessment of middle ear disorders. Results were compared with control data from two groups of adults, one with normal hearing (NH group) mean age of 31 years, and one that was age- and sex-matched with the Oto group and had sensorineural hearing loss (SNHL group). The goal was to assess group differences using absorbance and absorbed power, to determine test performance in detecting otosclerosis, and to evaluate preoperative and postoperative test results. Audiometric and wideband tests were performed over frequencies up to 8 kHz. The three groups were compared on wideband tests using analysis of variance to assess group mean differences. Receiver operating characteristic (ROC) curve analysis was also used to assess test accuracy at classifying ears as belonging to the Oto or control groups using the area under the ROC curve (AUC). A longitudinal design was used to compare preoperative and postoperative results at 3 and 6 months. There were significant mean differences in the wideband parameters between the Oto and control groups with generally lower absorbance and absorbed power for the Oto group at ambient and tympanometric peak pressure (TPP) depending on frequency. The SNHL group had more significant differences with the Oto group than did the NH group in the high frequencies for absorbed power at ambient pressure and tympanometric absorbed power at TPP, as well as for the tympanometric tails. The greatest accuracy for classifying ears as being in the Oto group or a control group was for absorbed power at ambient pressure at 0.71 kHz with an AUC of 0.81 comparing the Oto and NH groups. The greatest accuracy for an absorbance measure was for the comparison between the Oto and NH groups for the peak-to-negative tail condition with an AUC of 0.78. In contrast, the accuracy for classifying ears into the control or Oto groups for static acoustic admittance at 226 Hz was near chance performance, which is consistent with previous findings. There were significant mean differences between preoperative and postoperative tests for absorbance and absorbed power. Consistent with previous studies, wideband absorbance showed better sensitivity for detecting the effects of otosclerosis on middle ear function than static acoustic admittance at 226 Hz. This study showed that wideband absorbed power is similarly sensitive and may perform even better in some instances than absorbance at classifying ears as having otosclerosis. The use of a group that was age- and sex-matched to the Oto group generally resulted in greater differences between groups in the high frequencies for absorbed power, suggesting that age-related norms in adults may be useful for the wideband clinical applications. Absorbance and absorbed power appear useful for monitoring changes in middle ear function following surgery for otosclerosis.

RMS Delay Spread vs. Coherence Bandwidth from 5G Indoor Radio Channel Measurements at 3.5 GHz Band.

Our society has become fully submersed in fourth generation (4G) technologies, setting constant connectivity as the norm. Together with self-driving cars, augmented reality, and upcoming technologies, the new generation of Internet of Things (IoT) devices is pushing the development of fifth generation (5G) communication systems. In 5G architecture, increased capacity, improved data rate, and decreased latency are the objectives. In this paper, a measurement campaign is proposed; we focused on studying the propagation properties of microwaves at a center frequency of 3.5 GHz, commonly used in 5G cellular networks. Wideband measurement data were gathered at various indoor environments with different dimensions and characteristics. A ray-tracing analysis showed that the power spectrum is dominated by the line of sight component together with reflections on two sidewalls, indicating the practical applicability of our results. Two wideband parameters, root mean square delay spread and coherence bandwidth, were estimated for the considered scenarios, and we found that they are highly dependent on the physical dimension of the environment rather than on furniture present in the room. The relationship between both parameters was also investigated to provide support to network planners when obtaining the bandwidth from the delay spread, easily computed by a ray-tracing tool.

Wideband Performance Comparison between the 40 GHz and 60 GHz Frequency Bands for Indoor Radio Channels

When 5G networks are to be deployed, the usability of millimeter-wave frequency allocations seems to be left out of the debate. However, there is an open question regarding the advantages and disadvantages of the main candidates for this allocation: The use of the licensed spectrum near 40 GHz or the unlicensed band at 60 GHz. Both bands may be adequate for high performance radio communication systems, and this paper provides insight into such alternatives. A large measurement campaign supplied enough data to analyze and to evaluate the network performance for both frequency bands in different types of indoor environments: Both large rooms and narrow corridors, and both line of sight and obstructed line of sight conditions. As a result of such a campaign and after a deep analysis in terms of wideband parameters, the radio channel usability is analyzed with numerical data regarding its performance.

Empirical Characterization of the Indoor Radio Channel for Array Antenna Systems in the 3 to 4 GHz Frequency Band

Concerning the design and planning of new radio interfaces for the fifth-generation (5G) systems, this paper presents a useful contribution to the characterization of the wideband indoor radio channel in the 3-4-GHz frequency band. A measurement campaign has been carried out in two different indoor scenarios to analyze some of the most important wideband parameters of the propagation channel, including a thorough analysis of its behavior to meet the new radio technology challenges. The channel measurement setup consists of a virtual vertical uniform array at the receiver side of the link that remains at a fixed position, whereas the transmitter side, which is equipped with a single antenna, is placed at different positions in the environment under analysis. The measurement setup emulates the up-link of a multi-user multiple-input multiple-output (MIMO) system and allows obtaining the broadband parameters of the multiple channels that are established between the transmitter and each one of the antennas of the receiver array. The results and conclusions about the path loss, temporal dispersion, and coherence bandwidth are included, along with an analysis of the spatial correlation between wideband channels when one of the antennas is an array.

Efficient Multidimensional Wideband Parameter Estimation for OFDM Based Joint Radar and Communication Systems

In this paper, we propose a new pre-processing technique for efficient multidimensional wideband parameter estimation. One application is provided by an orthogonal frequency division multiplexing-(OFDM) based joint radar and communication system, which uses SIMO architecture. In this paper, the estimated parameters are given by the range (time delay), the relative velocity, and the direction of arrival (DoA) pairs of the dominant radar targets. Due to the wideband assumption, the received signals on different subcarriers are incoherent and, therefore, cannot fully exploit the frequency diversity of the OFDM waveform. To estimate the parameters jointly and coherently on different subcarriers, we propose an interpolation-based coherent multidimensional parameter estimation framework, where the wideband measurements are transformed into an equivalent narrowband system. Then, narrowband multidimensional parameter estimation algorithms can be applied. In particular, a wideband $R$ -D periodogram is introduced as a benchmark algorithm, and we develop the $R$ -D Wideband Unitary Tensor-ESPRIT algorithm. The simulations show that the proposed coherent parameter estimation method significantly outperforms the direct application of narrowband parameter estimation algorithms to the wideband measurements. If the fractional bandwidth is significant and the SNR is not too low, the estimates provided by the narrowband estimation algorithms can become inconsistent. Moreover, the interpolation order should be chosen according to the SNR regime. In the low SNR regime, interpolation with a lower-order (i.e., linear interpolation) is recommended. For higher SNRs, we propose an interpolation with higher-order polynomials, e.g., fourth-order (cubic splines) or even higher.

Doppler Stretch and Delay Statistical Performance Comparison for Wideband and Narrowband Signal Model

Narrowband approximation of Doppler effect by a frequency shift is inappropriate for some problems of radiolocation, hydro acoustics or passive location. In this case it is necessary to use Doppler stretch (time-scaling) as a signal parameter. Statistical performance of joint Doppler stretch and delay for arbitrary spectral width signal without narrowband approximations is derived in this paper.Narrowband and wideband parameters relations are investigated for triangle impulse with linear spectral modulation. Besides, Fisher Information Matrices (FIM) differences are analyzed. In the narrowband limit consideration of results in well-known FIM of Doppler shift and delay estimation are proposed. Another feature of wideband FIM is reference time dependence on time delay variance. Transition from Doppler stretch to Doppler frequency shift considering narrowband limitations results in translation invariant FIM.The article shows that reference time variance of delay estimation is related to estimated parameter modification and velocity influence on delay. Also, estimation variances in narrowband signal model differ from wideband parameter variances by magnitude of spectrum width to central frequency ratio.

A Statistical Model of the In-Home MIMO PLC Channel Based on European Field Measurements

The multiple-input multiple-output (MIMO) technique is well known in the field of wireless communications, and has recently been proposed to increase the capacity of in-home power line communication (PLC) networks. MIMO PLC employs the protective earth in addition to the classical line and neutral wires to form a multi-sensor transmission channel. By considering the additional reception of common-mode signals, up to two simultaneous transmit ports and four receive ports can be considered. In order to develop new signal processing strategies optimally exploiting the MIMO propagation characteristics and to evaluate their performance, the accurate modeling of the transmission channel is necessary. This paper presents a comprehensive statistical model of the in-home MIMO PLC channel based on an extensive measurement data base collected in six European countries. The paper first analyzes the main MIMO PLC channel parameters, including path loss parameters and wideband parameters, such as the delay spread, coherence bandwidth, and small-scale statistics. A focus is then made on the MIMO correlation matrix, and its modeling using empirical statistical distributions. A fully parameterized channel model is then developed, with a particular emphasis on both the frequency fading structure of the transfer function and the correlation matrix between sub-channels. As a result, the proposed model generates random MIMO PLC channel realizations, statistically representative of the experimental observations.

Versatile High Repetition Rate 2-μm Pulsed Source Based on Wideband Parametric Conversion

We report an all-fiber pulsed source based on parametric conversion followed by thulium amplification able to deliver picosecond pulses at a repetition rate selectable between 2 and 5 GHz, of which central wavelength can be freely selected in the 2-μm region. A very versatile Nyquist pulse shaping of the parametric pump, which allows for the electrical control of the pulse train, enables such a freedom in the repetition rate selection, as well as some control in the pulse duration. We also show that data can be embedded in the output pulse train resulting in a high-quality Gb/s return-to-zero transmitter. Such a programmable short-wave infrared laser is of high interest for sensing or nonlinear optics applications around 2000 nm that require a fine adjustment in both the spectral and temporal domains.

Integration of SCOR-Modeling and Logistical Concept of Management in the System of Internal Transportation of Milk Cooperative

Features of combined application of concepts/technologies of SCOR-modeling with logistical concept/technology of management of a separate link in a chain of supply in the milk business have been studied in the article. The term has been introduced and the essence has been provided of the private-cooperative, cooperative and mixed supply chain. The link of the cooperative supply chain “milk producer – serving cooperative” in the system of SCOR-model. Attention has been focused on rationalistic type of logistics as a base of logistical concept/technology for optimization of business processes in the system of SCМ. Mechanism and methodology of logistical optimization of internal transportation in the milk serving cooperative has been added focused on metrics of SCOR-model. Integrated application of SCOR-modeling has been suggested along with the method of linear programming on stages of creation (projecting) and functioning of the milk cooperative. Methods of formation of restrictions of mathematical model concerning possible negative effect from using additional points of milk gathering by cooperative through the mechanism of planning progressiveness (digressiveness) of additional transportation costs have been studied. Expediency of using in limited models both individualized or exact and averaged and wide-band parameters corresponding to factors of significant and insignificant influence on effectiveness of cooperative activity has been defined. Conditions of application of the developed methods and models for the level of planning with horizon moderate precision have been grounded. DOI: 10.5901/mjss.2015.v6n1s2p14

Wideband Parametric Frequency Comb as Coherent Optical Carrier

We report the first use of the CW-seeded parametric comb as a multiwavelength source for coherent channel transmitters. The new comb source relies on a multistage parametric mixer design seeded by a single kilohertz-linewidth master laser. The resultant frequency comb provides more than 120 tones in a 100-nm-wide continuous band, all possessing kilohertz-scale linewidth inherited from the master laser. The applicability of the new comb source as a coherent channel carrier was quantified by error-vector magnitude and bit-error rate metrics of individual spectral lines modulated by QPSK signaling. The performance of the new source exceeded that of the standard tunable coherent transmitter while providing a qualitatively lower frequency uncertainty and drift.

Wideband Parameters Analysis and Validation for Indoor radio Channel at 60/70/80GHz for Gigabit Wireless Communication employing Isotropic, Horn and Omni directional Antenna

Recently, applications of millimeter (mm) waves for high-speed broadband wireless local area network communication systems in indoor environment are increasingly gaining recognition as it provides gigabit-speed wireless communications with carrier-class performances over distances of a mile or more due to spectrum availability and wider bandwidth requirements. Collectively referred to as E-Band, the millimeter wave wireless technology present the potential to offer bandwidth delivery comparable to that of fiber optic, but without the financial and logistic challenges of deploying fiber. This paper investigates the wideband parameters using the ray tracing technique for indoor propagation systems with rms delay spread for Omnidirectional and Horn Antennas for Bent Tunnel at 80GHz. The results obtained were 2.03 and 1.95 respectively, besides, the normalized received power with 0:55fix10^8 excess delay at 70GHz for Isotropic Antenna was at 0.97.

Wideband Modeling of Land-Mobile-Satellite Channel in Built-Up Environment

This paper presents a propagation model for land-mobile-satellite (LMS) wideband radio channel in built-up environment. The model characterizes the behavior of the radio channel, under shadowing and multipath effects due to buildings, with variation of the elevation angle of the satellite. The wideband parameters (coherent bandwidth and time delay spreading) for LMS channel, in residential and urban environments, are computed. These parameters can be considered as a measure of the amount of ISI (inter-symbol interference) of the radio channel, which distorts the received signal and accordingly increases the bit error rate. The calculated values for these parameters using our model, show very good agreement with the corresponding measured ones, which accordingly shows the validity of the developed model for radio channel design in satellite mobile communication systems.

UWB Radio Propagation Measurements in a Desktop Environment

The ultra-wideband wireless personal area networks are expected to be most commonly employed in desktop environments. This paper presents a measurement campaignconducted on a typical office desk. A pair of omnidirectionalUWB antennas and a vector network analyzer were used tomeasure the impulse responses over a frequency rang spanning from 6 GHz to 8.5 GHz, in accordance with the UWB regulations in Europe. The coherence bandwidth and the rms delay spread are calculated from the measurement results. A significant correlation between these wideband parameters is found, but only at higher correlation thresholds.

1-to-40 10-Gb/s Channel Multicasting and Amplification in Wideband Parametric Amplifier

All-optical 1-to-40 multicasting of 10-Gb/s intensity modulated nonreturn-to-zero data is experimentally demonstrated in an architecture based on a one-pump modulated wideband parametric optical amplifier. The unique combination encompassing a wideband multicasting function and a gain function resulted in less than 0.5-dB power penalty and a minimum of 11.5-dB conversion efficiency with less than 1.35 dB of gain ripple.

Analysis of Multipath Propagation in Urban Environment Through Multidimensional Measurements and Advanced Ray Tracing Simulation

A multidimensional analysis of multipath propagation in urban micro- and macro-cellular environment has been carried out. Multidimensional measurement data, including path-loss, delay spread and direction-of-arrival are compared with simulations performed with a 3D ray tracing model which takes diffuse scattering into account. The results are analyzed highlighting the dominant propagation mechanisms in the different cases and model performance/shortcomings. In particular, the results show that diffuse scattering plays a key role in urban propagation, with an impact on both narrowband and wideband parameters in most cases. Also, the accuracy and the characteristics of environment representation can have a significant impact on prediction even in simple topologies.

AN APPROACH TO EQUIVALENT CIRCUIT MODELING OF RECTANGULAR MICROSTRIP ANTENNAS

Computation of the broadband matching potential of a microstrip antenna requires the wideband lumped equivalent circuit of the antenna. The general topology of the equivalent circuit of rectangular microstrip patch antennas has been used to model the feed- point impedance of microstrip antennas over a wide frequency band and equivalent circuit parameters are determined using optimization techniques. The proposed procedure overcomes the problems of physical realizability of the equivalent circuit and estimation of the starting values of the optimization. Applying this technique, wideband lumped equivalent circuits of a rectangular and E-shaped microstrip antenna have been computed which are in good agreement with measurement data from 0.1 to 6 GHz.

Improved band parameters for a simplified wide band cumulative absorption coefficient distribution model for H 2O and CO 2

An accurate and computationally efficient approach to evaluate wide band parameters with polynomial series for use in a simplified wide band cumulative absorption coefficient distribution, g( k), model is presented. The fitting coefficients are determined by a best fit with g( k) functions generated from the latest high resolution spectroscopic database. The approach significantly improves the prediction of the g( k) function over a wide range of temperatures from 500 to 2500 K, pressures from 0.01 to 1.0 atm, and all single bands of H 2O and CO 2. The root mean square error of the predicted absorption coefficient is below 25% except the single 4.3 μm band model. The approach also provides accurate calculations for the wide band absorptance, generally with differences below 7% when compared to benchmark results.

Asymptotic behavior of a low-dimensional model for magnetostriction for periodic input

Models for magnetostrictive actuators need to include rate-independent hysteresis phenomena, magneto-elastic coupling, and eddy current losses that vary nonlinearly with the frequency of the input. In this paper, we study a low-dimensional model for magnetostrictive rod actuators that describes the physical phenomena which are most prominent in the frequency range 0–800 Hz. We show that the solution of the system is asymptotically periodic for bounded, continuous and periodic voltage inputs and with general conditions on a Preisach operator modeling rate-independent hysteresis. The results of this paper are crucial for developing a parameter identification methodology for the model that is addressed in [D.B. Ekanayake, R.V. Iyer, W.P. Dayawansa, Wide band modeling and parameter identification in magnetostrictive actuators, in: Proceedings of IEEE American Control Conference, New York, NY (2007) 4321–4326].