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Journal articles on the topic 'TIME-DOMAIN CHANNEL'

Author: Grafiati

Published: 11 September 2023

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1

Huang, Sheng Bo, Yu Cang Wen, Wen Ye, and Tong Liang Fan. "A Simplified Time-Domain Channel Estimation Approach for OFDM System." Applied Mechanics and Materials 738-739 (March 2015): 1111–14. http://dx.doi.org/10.4028/www.scientific.net/amm.738-739.1111.

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OFDM usually incorporates pilot tones in the frequency domain (FD) or training symbols in the time-domain (TD) to facilitate channel estimation algorithms. TD channel estimation becomes more attractive in quasi-static channels because channel estimation scheme will optimize the spectral efficiency by re-using the training symbols designated for FD channel estimation. A channel estimation method based on time domain averaging algorithm is proposed. Due to the principle of centralized energy in time domain, the effective channel impulse response length can be detected by setting of threshold for the estimated channel impulse response length. Computer simulation demonstrates the performance of the proposed algorithms in terms of bit error rate performance.

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2

Ningna Yu, Ningna Yu, Zhaoyue Dong Zhaoyue Dong, Jindong Wang Jindong Wang, Zhengjun Wei Zhengjun Wei, and Zhiming Zhang Zhiming Zhang. "Impact of spontaneous Raman scattering on quantum channel wavelength-multiplexed with classical channel in time domain." Chinese Optics Letters 12, no. 10 (2014): 102703–6. http://dx.doi.org/10.3788/col201412.102703.

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3

Ivanov, V. D. "Time-Domain Instrumentation at ESO." Proceedings of the International Astronomical Union 14, S339 (November 2017): 172–75. http://dx.doi.org/10.1017/s1743921318002508.

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AbstractOver the years the European Southern Observatory (ESO) has offered a number of time-domain instruments that enable the user to achieve time resolution as small as milliseconds. They have been used for a wide range of applications, from binary studies with Lunar occultations, characterisation of X-ray binaries and exoplanet transits, to quasar variability. Furthermore, ESO provides a target-of-opportunity (ToO) rapid-response-mode (RRM) channel to trigger quick follow-up observations within as little delay as minutes after a transient has been detected. This talk reviewed the available time-domain observing modes and instruments at ESO, giving priority to FORS2, HAWKI and UltraCam. It described the ToO and RRM, and gave examples of the most common science cases that take advantage of those channels and capabilities.

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4

Kekalainen, Jorma. "A discrete time domain approach on time delay estimation." ACTA IMEKO 8, no. 1 (March 31, 2019): 77. http://dx.doi.org/10.21014/acta_imeko.v8i1.600.

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A time delay estimation method based on the discrete time domain approach is introduced here. In this dual-channel time delay estimation model, the criterion function compares the time differences of time sequences between channels, not the magnitude values of time functions as in the conventional cross-correlation method. An estimation task is formulated as an extreme value problem in discrete index space. Using the index delay giving extreme value to the criterion function, it is possible to find the best estimate for time delay distribution in the meaning of that criterion. Using this method, the estimated delay distribution and criterion function are clearly separated. Thus, there are no theoretical problems in the determination of the average time delay or velocity in the non-constant or changing time delay case as long as a sufficient statistical similarity (correlation) exists between channel signals. <p class="Abstract">The theoretical values of several criterion functions and the probability of occurrence of an anomalous estimate with the cross-covariance criterion function are derived. A basic performance analysis of the estimation method is presented. Some potential real-time supervision methods based on the use of criterion functions in the detection of the possible unreliability of the time delay estimate are outlined.</p>

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5

Asharjabi, Sami, Hefdhallah Sakran, and Azzam Al-nahari. "Time-Domain Channel Estimation Scheme for OFDM over Fast Fading Channels." Wireless Communications and Mobile Computing 2022 (February 27, 2022): 1–9. http://dx.doi.org/10.1155/2022/7839430.

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In high-mobility scenarios, the time variation of mobile radio channels leads to a loss of orthogonality among subcarriers in orthogonal frequency division multiplexing (OFDM) systems, resulting in intercarrier interference (ICI) and performance deterioration. Conventional channel estimation schemes are usually based on pilot tones, which are distributed in each OFDM symbol to estimate the channel variation. Hence, the channel estimator itself suffers from ICI. In this study, a new estimation scheme, which does not suffer from ICI, is proposed to estimate the channel variation within OFDM symbols. The main idea is to zero-pad (ZP) the OFDM symbol in the time domain. Then, in the middle of the ZP interval, an impulse signal is inserted as a pilot sample, which is used to estimate the channel at the pilot signal in the OFDM symbol. Finally, a linear model is used to estimate the channel variation over an OFDM symbol. Additionally, we derive the mean squared error (MSE) of the proposed estimation technique under the constraint that the channel varies linearly within OFDM symbols. Simulation results show that our scheme can achieve a substantial improvement in the bit error rate (BER) performance of OFDM, in spite of the OFDM symbol length being increased. Moreover, in many cases, the new scheme can achieve the same BER performance as the perfect knowledge of channel state information (CSI). Theoretical analysis and numerical simulations show that our scheme achieves excellent performance with much lower computational complexity.

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6

Vychodil, Josef, Martin Pospisil, Ales Prokes, and Jiri Blumenstein. "Millimetre wave band time domain channel sounder." IET Communications 13, no. 3 (February 19, 2019): 331–38. http://dx.doi.org/10.1049/iet-com.2018.5453.

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7

Park, Yongkoo, and Wonzoo Chung. "Selective Feature Generation Method Based on Time Domain Parameters and Correlation Coefficients for Filter-Bank-CSP BCI Systems." Sensors 19, no. 17 (August 30, 2019): 3769. http://dx.doi.org/10.3390/s19173769.

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This paper presents a novel motor imagery (MI) classification algorithm using filter-bank common spatial pattern (FBCSP) features based on MI-relevant channel selection. In contrast to existing channel selection methods based on global CSP features, the proposed algorithm utilizes the Fisher ratio of time domain parameters (TDPs) and correlation coefficients: the channel with the highest Fisher ratio of TDPs, named principle channel, is selected and a supporting channel set for the principle channel that consists of highly correlated channels to the principle channel is generated. The proposed algorithm using the FBCSP features generated from the supporting channel set for the principle channel significantly improved the classification performance. The performance of the proposed method was evaluated using BCI Competition III Dataset IVa (18 channels) and BCI Competition IV Dataset I (59 channels).

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8

Sevcik, Bretislav. "Time-Domain Predistortion Method Based on Raised Cosine Signaling in Real Transmission Channels." Active and Passive Electronic Components 2012 (2012): 1–5. http://dx.doi.org/10.1155/2012/596481.

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The concept of time-domain predistortion method based on raised cosine signaling is applied in real transmission channels. The proposed PWM-RC method uses raised-cosine pulse shaping instead of conventional rectangular digital signals and pulse-width modulation (PWM) scheme to achieve better output channel data response in harsh channel environment. The conventional predistortion methods based on pulse amplitude adjusting are not compatible with modern low-power CMOS design. Currently existing time-domain predistortion methods which are only based on a PWM scheme show many highfrequency signal harmonic components for both fast and slow signal transitions. It can cause more system crosstalk susceptibility if the crosstalk is dominant factor in transmission channel. In this case, the additional preemphasis boosted undesirable high-frequency components. Finally, the real channel transfer functions in connection with ADS Agilent development studio are used to compare the performance of proposed method with other predistortion methods.

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9

Sahu, O. P., M. K. Soni, and I. M. Talwar. "Time Domain Analysis of Two-Channel QMF Bank." IETE Journal of Research 51, no. 6 (November 2005): 469–75. http://dx.doi.org/10.1080/03772063.2005.11416427.

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10

Artigas, Jordi, Jee-Hwan Ryu, and Carsten Preusche. "Time Domain Passivity Control for Position-Position Teleoperation Architectures." Presence: Teleoperators and Virtual Environments 19, no. 5 (October 1, 2010): 482–97. http://dx.doi.org/10.1162/pres_a_00013.

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This article presents a method for passivating the communication channel of a symmetric position-position teleoperation architecture on the time domain. The time domain passivity control approach has recently gained appeal in the context of timedelayed teleoperation because passivity is not established as a design constraint, which often forces conservative rules, but rather as a property which the system must preserve during operation. Since passivity is a network property, the first design rule within this framework is to represent consistent and comprehensible circuit (i.e., network) representations of the mechanical teleoperation system. In particular, the energetic behavior of these networks is interesting because it allows straightforward conclusions about system stability. By means of so-called passivity observers (PO) and passivity controllers (PC) (Hannaford & Ryu, 2001), the energetic response of a delayed communication channel is captured and modulated over time so that the network in question never becomes nonpassive. The case analyzed in this paper tackles a communication channel that conveys position data back and forth. This type of channel does not offer intuitive network representation since only flows are actually being transmitted. Although energy clearly travels from one side to the other, port power identification, as defined by the correlated pair flow and effort, is not evident. This work first investigates how this kind of channel can be represented by means of circuit networks even with the lack of physical effort being transmitted through the channel, and identifies which networks are susceptible to become nonpassive due to the channel characteristics (i.e., time delay, discretization or package loss). Once achieved, a distributed control structure is presented based on a PC series that keeps the system at the verge of passivity (and therefore stability) independent from the channel properties. The results obtained by the simulation and by experiment sustain the presented approach.

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11

Moss, Brenda L., and Karl L. Magleby. "Gating and Conductance Properties of Bk Channels Are Modulated by the S9–S10 Tail Domain of the α Subunit." Journal of General Physiology 118, no. 6 (November 26, 2001): 711–34. http://dx.doi.org/10.1085/jgp.118.6.711.

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The COOH-terminal S9–S10 tail domain of large conductance Ca2+-activated K+ (BK) channels is a major determinant of Ca2+ sensitivity (Schreiber, M., A. Wei, A. Yuan, J. Gaut, M. Saito, and L. Salkoff. 1999. Nat. Neurosci. 2:416–421). To investigate whether the tail domain also modulates Ca2+-independent properties of BK channels, we explored the functional differences between the BK channel mSlo1 and another member of the Slo family, mSlo3 (Schreiber, M., A. Yuan, and L. Salkoff. 1998. J. Biol. Chem. 273:3509–3516). Compared with mSlo1 channels, mSlo3 channels showed little Ca2+ sensitivity, and the mean open time, burst duration, gaps between bursts, and single-channel conductance of mSlo3 channels were only 32, 22, 41, and 37% of that for mSlo1 channels, respectively. To examine which channel properties arise from the tail domain, we coexpressed the core of mSlo1 with either the tail domain of mSlo1 or the tail domain of mSlo3 channels, and studied the single-channel currents. Replacing the mSlo1 tail with the mSlo3 tail resulted in the following: increased open probability in the absence of Ca2+; reduced the Ca2+ sensitivity greatly by allowing only partial activation by Ca2+ and by reducing the Hill coefficient for Ca2+ activation; decreased the voltage dependence ∼28%; decreased the mean open time two- to threefold; decreased the mean burst duration three- to ninefold; decreased the single-channel conductance ∼14%; decreased the Kd for block by TEAi ∼30%; did not change the minimal numbers of three to four open and five to seven closed states entered during gating; and did not change the major features of the dependency between adjacent interval durations. These observations support a modular construction of the BK channel in which the tail domain modulates the gating kinetics and conductance properties of the voltage-dependent core domain, in addition to determining most of the high affinity Ca2+ sensitivity.

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12

Liu, Hui, Jing Shan Jiao, Fu Chun Zhang, and Ling Zhou. "Channel Estimating Based on Space-Time-Frequency Pilot for MIMO-OFDM." Advanced Materials Research 429 (January 2012): 179–85. http://dx.doi.org/10.4028/www.scientific.net/amr.429.179.

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The pilots that are transmitted by different transmitting antennas must be orthogonal after being shifted. So the time domain channel estimating solution is deduced through LS based on the MIMO-OFDM channel estimating model. The time domain solution need the inverse operation of matrix, and its operating quantity is large. So the three dimensions pilot based on space domain, time domain and frequency domain is designed. The method need not the inverse operation of matrix for the time domain channel estimating solution and can reduce the complexity of channel estimating and make the channel estimating error minimum. It is shown from the simulation that the channel estimating method of this paper based on space domain, time space and frequency domain pilot has better MSE and BER performances compared with the traditional LS algorithm and the document algorithm.

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13

Muluneh, Melaku, Bawul Kim, Gershon Buchsbaum, and David Issadore. "Miniaturized, multiplexed readout of droplet-based microfluidic assays using time-domain modulation." Lab Chip 14, no. 24 (2014): 4638–46. http://dx.doi.org/10.1039/c4lc00819g.

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We have developed a miniaturized fluorescence detection platform for droplet based assays that can monitor multiple channels using only a single photodetector and no lenses. To accomplish this, we take advantage of the high bandwidth of electronics and encode the signal from each channel using distinct micropatterned masks.

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14

Zhou, Chenming, Ronald Jacksha, Lincan Yan, Miguel Reyes, and Peter Kovalchik. "TIME DOMAIN AND FREQUENCY DOMAIN DETERMINISTIC CHANNEL MODELING FOR TUNNEL/MINING ENVIRONMENTS." Progress In Electromagnetics Research C 79 (2017): 209–23. http://dx.doi.org/10.2528/pierc17082907.

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15

Mohammed, Asaad, and Maher K. Mahmood Al-Azawi. "COMPARISON OF TIME AND TIME-FREQUENCY DOMAINS IMPULSIVE NOISE MITIGATION TECHNIQUES FOR POWER LINE COMMUNICATIONS." Journal of Engineering and Sustainable Development 27, no. 1 (January 1, 2023): 68–79. http://dx.doi.org/10.31272/jeasd.27.1.6.

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Impulsive noise is one of the foremost situations in power line communications that degrades the performance of orthogonal frequency division multiplexing used for the power line communications channel. In this paper, a channel version of the broadband power line communications is assumed when evaluating the bit error rate performance. Three impulsive noise environments are assumed, namely heavily, moderately, and weakly disturbed. The well-known time domain mitigation techniques are tested first. These are clipping, blanking, and mixing clipping with blanking. The results of Matlab simulations show that these time-domain mitigation techniques don't significantly improve the bit error rate performance. A hybrid domain of time and frequency mitigation techniques are used to enhance the bit error rate performance. The Matlab simulation results show that this hybrid domain of time and frequency approach outperforms time domain nonlinearities and can largely improve the bit error rate performance. Signal-to-noise ratio gains of about 8 dB, 10 dB, and 10 dB are obtained for heavily, moderately, and weakly disturbed channels, respectively, using the domains of time and frequency mitigation technique at a bit error rate of when compared to the blanking time domain technique.

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16

Rebelo, Joao, and Andre Schiele. "Time Domain Passivity Controller for 4-Channel Time-Delay Bilateral Teleoperation." IEEE Transactions on Haptics 8, no. 1 (January 1, 2015): 79–89. http://dx.doi.org/10.1109/toh.2014.2363466.

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17

Linglong Dai, Zhaocheng Wang, Jun Wang, and Zhixing Yang. "Joint Time-Frequency Channel Estimation for Time Domain Synchronous OFDM Systems." IEEE Transactions on Broadcasting 59, no. 1 (March 2013): 168–73. http://dx.doi.org/10.1109/tbc.2012.2219231.

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18

Ma, Debiao, Junteng Zheng, and Lizhi Peng. "Performance Evaluation of Epileptic Seizure Prediction Using Time, Frequency, and Time–Frequency Domain Measures." Processes 9, no. 4 (April 13, 2021): 682. http://dx.doi.org/10.3390/pr9040682.

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The prediction of epileptic seizures is crucial to aid patients in gaining early warning and taking effective intervention. Several features have been explored to predict the onset via electroencephalography signals, which are typically non-stationary, dynamic, and varying from person-to-person. In the former literature, features applied in the classification have shared similar contributions to all patients. Therefore, in this paper, we analyze the impact of the specific combination of feature and channel from time, frequency, and time–frequency domains on prediction performance of disparate patients. Based on the minimal-redundancy-maximal-relevance criterion, the proposed framework uses a sequential forward selection approach to individually find the optimal features and channels. Trained models could discriminate the pre-ictal and inter-ictal electroencephalography with a sensitivity of 90.2% and a false prediction rate of 0.096/h. We also present the comparison between the classification accuracy obtained by the optimal features, several features summarized from optimal features, and the complete set of features from three domains. The results indicate that various patient interpretations have a certain specificity in the selection of feature-channel. Furthermore, the detailed list of optimal features and summarized features are proffered for reference to those who research the corresponding database.

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19

Kumar, Udaya, Rosy B. Raysaha, and K. P. Dileep Kumar. "Time Domain Modelling of First Return Stroke of Lightning." Open Atmospheric Science Journal 2, no. 1 (December 29, 2008): 261–70. http://dx.doi.org/10.2174/1874282300802010261.

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The four most important factors that govern the return stroke evolution can be identified as: (i) electric field due to charge distributed along the channel, (ii) transient enhancement of conductance by several orders at the bridging regime (iii) the non-linear increase in channel conductance at the propagating current front and (iv) the associated dynamic electromagnetic field which support the evolution of current along the channel. For a more realistic modelling of the lightning return stroke, the present work attempts to consider these aspects in suitable manner. The charge simulation method is employed for evaluating the quasi-static field due to (i). For the dynamic field, the problem involves conduction along a thin structure with open boundary on one side. Further, in order to efficiently represent a vertically extended grounded strike object, as well as, channel of quite arbitrary geometry, boundary based approach is believed to be the ideal choice. Considering these, a time-dependent electric field integral equation (TD-EFIE) along with a sub-sectional collocation form of the method of moments (MoM) is chosen for the numerical field evaluation. The dynamic variation of conductance in the channel other than the bridging zone is modelled by a first order arc equation. For the bridging zone, arc equation which explicitly portray in some sense, accumulation of energy is considered. Accordingly, formulations given by Barannik, Popovic and Toepler were scrutinized for their suitability. After some preliminary simulation studies, a self contained model for the first return stoke of a lightning flash is presented. The stability of the model is verified by running the program for longer durations with different cloud base potentials and cloud base heights. Simulation results are in agreement with the field data on current and velocity decay rate for the first one kilometer height. Also, the relation between the charge density at channel tip and the return stroke current peak favorably compares with the literature.

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20

Xing, Xingxing, Amir Feizpour, Alex Hayat, and Aephraim M. Steinberg. "Experimental demonstration of a flexible time-domain quantum channel." Optics Express 22, no. 21 (October 7, 2014): 25128. http://dx.doi.org/10.1364/oe.22.025128.

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21

Hao Zhou, A. Malipatil, and Yih-Fang Huang. "OFDM Carrier Synchronization Based on Time-Domain Channel Estimates." IEEE Transactions on Wireless Communications 7, no. 8 (August 2008): 2988–99. http://dx.doi.org/10.1109/twc.2008.060765.

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22

Singh, Prem, and K. Vasudevan. "Time Domain Channel Estimation for MIMO-FBMC/OQAM Systems." Wireless Personal Communications 108, no. 4 (May 13, 2019): 2159–78. http://dx.doi.org/10.1007/s11277-019-06515-7.

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23

Bankson, James A., and Steven M. Wright. "Multi-channel magnetic resonance spectroscopy through time domain multiplexing." Magnetic Resonance Imaging 19, no. 7 (September 2001): 1001–8. http://dx.doi.org/10.1016/s0730-725x(01)00425-8.

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24

Jang, G. J., Te-Won Lee, and Yung-Hwan Oh. "Single-channel signal separation using time-domain basis functions." IEEE Signal Processing Letters 10, no. 6 (June 2003): 168–71. http://dx.doi.org/10.1109/lsp.2003.811630.

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25

Zhu, M., A. B. Awoseyila, and B. G. Evans. "Low-complexity time-domain channel estimation for OFDM systems." Electronics Letters 47, no. 1 (2011): 60. http://dx.doi.org/10.1049/el.2010.7204.

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26

Gustina, Ahleah S., and Matthew C. Trudeau. "The eag domain regulates hERG channel inactivation gating via a direct interaction." Journal of General Physiology 141, no. 2 (January 14, 2013): 229–41. http://dx.doi.org/10.1085/jgp.201210870.

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Human ether-á-go-go (eag)-related gene (hERG) potassium channel kinetics are characterized by rapid inactivation upon depolarization, along with rapid recovery from inactivation and very slow closing (deactivation) upon repolarization. These factors combine to create a resurgent hERG current, where the current amplitude is paradoxically larger with repolarization than with depolarization. Previous data showed that the hERG N-terminal eag domain regulated deactivation kinetics by making a direct interaction with the C-terminal region of the channel. A primary mechanism for fast inactivation depends on residues in the channel pore; however, inactivation was also shown to be slower after deletion of a large N-terminal region. The mechanism for N-terminal region regulation of inactivation is unclear. Here, we investigated the contributions of the large N-terminal domains (amino acids 1–354), including the eag domain (amino acids 1–135), to hERG channel inactivation kinetics and steady-state inactivation properties. We found that N-deleted channels lacking just the eag domain (Δ2–135) or both the eag domain and the adjacent proximal domain (Δ2–354) had less rectifying current–voltage (I-V) relationships, slower inactivation, faster recovery from inactivation, and lessened steady-state inactivation. We coexpressed genetically encoded N-terminal fragments for the eag domain (N1–135) or the eag domain plus the proximal domain (N1–354) with N-deleted hERG Δ2–135 or hERG Δ2–354 channels and found that the resulting channels had more rectifying I-V relationships, faster inactivation, slower recovery from inactivation, and increased steady-state inactivation, similar to those properties measured for wild-type (WT) hERG. We also found that the eag domain–containing fragments regulated the time to peak and the voltage at the peak of a resurgent current elicited with a ramp voltage protocol. The eag domain–containing fragments effectively converted N-deleted channels into WT-like channels. Neither the addition of the proximal domain to the eag domain in N1–354 fragments nor the presence of the proximal domain in hERG Δ2–135 channels measurably affected inactivation properties; in contrast, the proximal region regulated steady-state activation in hERG Δ2–135 channels. The results show that N-terminal region-dependent regulation of channel inactivation and resurgent current properties are caused by a direct interaction of the eag domain with the rest of the hERG channel.

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27

Barellini, Andrea, Barbara Bracci, Gaetano Licitra, and Alberto Maria Silvi. "Time Domain Analysis of NB-IoT Signals." Applied Sciences 13, no. 4 (February 9, 2023): 2242. http://dx.doi.org/10.3390/app13042242.

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The NB-IoT (NarrowBand-Internet of Things) radio technology is now widely implemented by mobile phone network operators to support the communication of IoT devices such as smart meters, insurance black boxes for cars, network connected waste bins, smart bicycles. In the present work, some LTE800 cells of different mobile phone network operators implementing the NB-IoT technology in the guard band mode have been investigated. The signals, consisting of a PRB (Physical Resource Block) 180 kHz wide, have been analyzed and characterized in the time domain by means of a narrow band instrumental chain equipped with a Rohde & Schwarz FSH8 spectrum analyzer. Time domain analysis allows us to identify, within the transmission frame, the position of the NB-IoT signaling channels such as the Narrowband Reference Signal (NRS), the primary (NPSS) and secondary (NSSS) synchronization signals and the broadcast channel (NPBCH), but, above all, to measure the power received during the transmission of the NRS. This value has been compared with that measured by the NB-IoT decoding module supplied on the same analyzer, in order to verify the equivalence of these measurement methods. This would allow use of a more diffuse and cheaper instrumentation rather than more expensive vector analyzers, currently required to assess electric fields due to the NB-IoT signals through the extrapolation techniques set by Italian CEI 211-7/E technical standard.

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Wei, Ziliang, Yangrong Wen, Yueming Gao, Mingjing Yang, Jiejie Yang, Sio Hang Pun, Mang Vai, and Min Du. "A Time-Frequency Measurement and Evaluation Approach for Body Channel Characteristics in Galvanic Coupling Intrabody Communication." Sensors 21, no. 2 (January 6, 2021): 348. http://dx.doi.org/10.3390/s21020348.

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Intrabody communication (IBC) can achieve better power efficiency and higher levels of security than other traditional wireless communication technologies. Currently, the majority of research on the body channel characteristics of galvanic coupling IBC are motionless and have only been evaluated in the frequency domain. Given the long measuring times of traditional methods, the access to dynamic variations and the simultaneous evaluation of the time-frequency domain remains a challenge for dynamic body channels such as the cardiac channel. To address this challenge, we proposed a parallel measurement methodology with a multi-tone strategy and a time-parameter processing approach to obtain a time-frequency evaluation for dynamic body channels. A group search algorithm has been performed to optimize the crest factor of multitone excitation in the time domain. To validate the proposed methods, in vivo experiments, with both dynamic and motionless conditions were measured using the traditional method and the proposed method. The results indicate that the proposed method is more time efficient (Tmeas = 1 ms) with a consistent performance (ρc > 98%). Most importantly, it is capable of capturing dynamic variations in the body channel and provides a more comprehensive evaluation and richer information for the study of IBC.

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Khalid, Muhammad, Abid Muhammad Khan, Muhammad Rauf, Muhammad Taha Jilani, and Sheraz Afzal. "FPGA-Based Time-Domain Channel Estimation in Gaussian Mixture Model." Mathematical Problems in Engineering 2021 (May 3, 2021): 1–12. http://dx.doi.org/10.1155/2021/5596301.

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The performance of time-domain channel estimation deteriorates due to the presence of Gaussian mixture model (GMM) noise, which results in high mean squared error (MSE) as a challenging issue. The performance of the estimator further decreases when the complexity of the estimator is high due to the high convergence rate. In this paper, an optimized channel estimation method is proposed with low complexity and high accuracy in the GMM environment. In this channel estimation, an improved Gauss-Seidel iterative method is utilized with a minimum number of iterations. The convergence rate of the Gauss-Seidel method is improved by estimating an appropriate initial guess value when no guard bands are used in the orthogonal frequency-division multiplexing (OFDM) symbol. Simulation results provide an acceptable MSE for GMM environments, up to the probability of 5% impulsive noise component. This paper also presents the design and implementation of the proposed estimator in the NEXYS-2 FPGA platform that provides resources allocation, reconfigurability, schematic, and the timing diagram for detailed insight.

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30

Yun, Deok-Won, and Won-Cheol Lee. "Intelligent Dynamic Spectrum Resource Management Based on Sensing Data in Space-Time and Frequency Domain." Sensors 21, no. 16 (August 4, 2021): 5261. http://dx.doi.org/10.3390/s21165261.

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Edge computing offers a promising paradigm for implementing the industrial Internet of things (IIoT) by offloading intensive computing tasks from resource constrained machine type devices to powerful edge servers. However, efficient spectrum resource management is required to meet the quality of service requirements of various applications, taking into account the limited spectrum resources, batteries, and the characteristics of available spectrum fluctuations. Therefore, this study proposes intelligent dynamic spectrum resource management consisting of learning engines that select optimal backup channels based on history data, reasoning engines that infer idle channels based on backup channel lists, and transmission parameter optimization engines based genetic algorithm using interference analysis in time, space and frequency domains. The performance of the proposed intelligent dynamic spectrum resource management was evaluated in terms of the spectrum efficiency, number of spectrum handoff, latency, energy consumption, and link maintenance probability according to the backup channel selection technique and the number of IoT devices and the use of transmission parameters optimized for each traffic environment. The results demonstrate that the proposed method is superior to existing spectrum resource management functions.

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Ju, Mei-yan, and Ming Ran. "Channel Estimation in Time Domain and Frequency Domain for Multiuser MC DS-CDMA Systems." Journal of Electronics & Information Technology 30, no. 10 (April 13, 2011): 2537–40. http://dx.doi.org/10.3724/sp.j.1146.2007.01490.

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Chen, Cheng-Tsung, Jaw-Fang Lee, Hubert Chanson, Kuei-Ting Lin, and Chun-Jih Lin. "A Time-Domain Analytic Solution of Flow-Induced Undular Bores." Journal of Marine Science and Engineering 10, no. 6 (May 27, 2022): 738. http://dx.doi.org/10.3390/jmse10060738.

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In this study, the problem of surface waves induced by water flow in a flow channel was investigated. The mathematical model based on the potential wave theory was established, and a new analytic solution to the corresponding initial and boundary value problem was proposed. To confirm our analytic solution, the mathematical model was applied to simulate experiments conducted in a flow channel in the laboratory. Using our analytic solution, water surface elevations and flow velocities at certain locations in the channel were compared with experimental results. Comparisons between our analytic solution and experimental results confirmed our theory that amplitudes and propagating phases are in very close agreement. Our analytic solution can be used to calculate variations in pressure and velocity along the water depth, which are expensive to calibrate and obtain in experiments. Although our analytic solution was established based on linear theory, it is very practical for applications studying the basic properties of surface elevation, velocity, and pressure of the flow field induced by water current both in space and time.

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LIU, Fengwei, Hongzhi ZHAO, Ying LIU, and Youxi TANG. "Eigen Domain Channel-Unaware Narrowband Interference Suppression for Time Synchronization." IEICE Transactions on Communications E99.B, no. 5 (2016): 1151–56. http://dx.doi.org/10.1587/transcom.2015ebp3331.

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Lu, Zhen, and Jian-hua Ge. "Time-domain training sequences design for MIMO OFDM channel estimation." Journal of Zhejiang University-SCIENCE A 9, no. 4 (April 2008): 464–69. http://dx.doi.org/10.1631/jzus.a071444.

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Pal, Joydeep, Kaushik Patra, and Bhaskar Gupta. "Antenna-Independent Frequency- and Time-Domain Representation of Wireless Channel." IEEE Antennas and Wireless Propagation Letters 19, no. 8 (August 2020): 1447–51. http://dx.doi.org/10.1109/lawp.2020.3005419.

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Garcia-Pardo, Concepcion, Jose-Maria Molina-Garcia-Pardo, and Leandro Juan-Llacer. "Time-Domain MIMO Channel Sounder Based on Code-Division Multiplexing." IEEE Transactions on Instrumentation and Measurement 61, no. 8 (August 2012): 2325–27. http://dx.doi.org/10.1109/tim.2012.2188069.

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Zeng, Rong, Qiang Huang, and Hao Wang. "Orthogonal Spatial Domain Subspace Projection Based Time-Varying Channel Estimation." IEEE Access 8 (2020): 79203–9. http://dx.doi.org/10.1109/access.2020.2990316.

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Yin, Zhendong, Zhenguo Shi, Guowei Qi, and Yi Zhou. "Time Domain DS-UWB Channel Estimation using Maximum Likelihood Algorithm." Information Technology Journal 10, no. 1 (December 15, 2010): 127–33. http://dx.doi.org/10.3923/itj.2011.127.133.

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Jensen, Jesper Rindom, Jacob Benesty, Mads Græsbøll Christensen, and Søren Holdt Jensen. "Non-Causal Time-Domain Filters for Single-Channel Noise Reduction." IEEE Transactions on Audio, Speech, and Language Processing 20, no. 5 (July 2012): 1526–41. http://dx.doi.org/10.1109/tasl.2012.2183872.

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Jensen, Jesper Rindom, Jacob Benesty, Mads Græsbøll Christensen, and Søren Holdt Jensen. "Enhancement of Single-Channel Periodic Signals in the Time-Domain." IEEE Transactions on Audio, Speech, and Language Processing 20, no. 7 (September 2012): 1948–63. http://dx.doi.org/10.1109/tasl.2012.2191957.

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Bishnu, Abhijeet, and Vimal Bhatia. "Iterative Time-Domain-Based Sparse Channel Estimation for IEEE 802.22." IEEE Wireless Communications Letters 6, no. 3 (June 2017): 290–93. http://dx.doi.org/10.1109/lwc.2017.2675419.

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Minn, H., and V. K. Bhargava. "An investigation into time-domain approach for OFDM channel estimation." IEEE Transactions on Broadcasting 46, no. 4 (2000): 240–48. http://dx.doi.org/10.1109/11.898744.

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Lu, Wei, Yongliang Wang, Xiaoqiao Wen, Shixin Peng, and Liang Zhong. "Downlink Channel Estimation in Massive Multiple-Input Multiple-Output with Correlated Sparsity by Overcomplete Dictionary and Bayesian Inference." Electronics 8, no. 5 (April 28, 2019): 473. http://dx.doi.org/10.3390/electronics8050473.

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We exploited the temporal correlation of channels in the angular domain for the downlink channel estimation in a massive multiple-input multiple-output (MIMO) system. Based on the slow time-varying channel supports in the angular domain, we combined the channel support information of the downlink angular channel in the previous timeslot into the channel estimation in the current timeslot. A downlink channel estimation method based on variational Bayesian inference (VBI) and overcomplete dictionary was proposed, in which the support prior information of the previous timeslot was merged into the VBI for the channel estimation in the current timeslot. Meanwhile the VBI was discussed for a complex value in our system model, and the structural sparsity was utilized in the Bayesian inference. The Bayesian Cramér–Rao bound for the channel estimation mean square error (MSE) was also given out. Compared with other algorithms, the proposed algorithm with overcomplete dictionary achieved a better performance in terms of channel estimation MSE in simulations.

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Wang, Cheng, and Bin Yang. "The Super-Exponential Algorithm of Blind Equalization for Time-Varying Channel Based on Basis Expansion Model." Advanced Materials Research 756-759 (September 2013): 3125–30. http://dx.doi.org/10.4028/www.scientific.net/amr.756-759.3125.

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Existing algorithms of blind equalization for time-varying channels are slow in convergence, easily interfered, and hard to pinpoint the location of pulsation in the frequency domain. In this paper we present a new blind equalization method that addresses the aforementioned issues. The new solution combines super-exponential algorithm with carrier frequency-offset estimation for time-varying channels. The time-varying channel taps described by the complex exponential basis expansion model (CE-BEM) are expressed as a superposition of time-varying complex exponential bases with time-invariant coefficients. We first employ a super-exponential algorithm to remove the inter-symbol interference caused by time-invariant coefficients. Then we estimate channel pulsation from equalized signals with a carrier frequency-offset estimation algorithm. Compared with existing ones, our solution converges faster with lower inter-symbol interference and easier specification of the pulsation in frequency domain. Simulation results prove the efficiency of the proposed algorithm.

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Lv, Changwei, Shujuan Hou, and Wenbo Mei. "Adaptive Prediction of Channels with Sparse Features in OFDM Systems." International Journal of Antennas and Propagation 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/649602.

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A time domain channel prediction method exploiting features of sparse channel is proposed for orthogonal frequency division multiplexing (OFDM) systems. The proposed predictor operates in the time domain on each channel tap and separates the negligible taps from significant channel taps before performing prediction. We also compare the proposed prediction method with the classical frequency domain method realized at each OFDM subcarrier and demonstrate that our method increases the prediction accuracy and reduces the computational complexity. Simulations on the physical channel model verify the performance of the proposed method.

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Han, Feiyan, Juan Wei, Bin Feng, and Wu Zhang. "A High-Efficiency Impeller Channel Quasi-Triangular Tool Path Planning Method Based on Template Trajectory Mapping." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 36, no. 6 (December 2018): 1216–23. http://dx.doi.org/10.1051/jnwpu/20183661216.

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The manufacturing technology of an integral impeller is an important indicator for measuring the manufacturing capability of a country. Its manufacturing process involves complex free-form surface machining, a time consuming and error-prone process, and the tool path planning is considered as a critical issue of free-form surface machining but still lacks a systematic solution. In this paper, aiming at the tool path planning of the impeller channel, a quasi-triangular tool path planning method based on parametric domain template trajectory mapping is proposed. The main idea is to map the template trajectory to physical domain by using the mapping model of parametric domain to the physical domain to obtain the actual machining path. Firstly, the trajectory mapping model of parametric domain to physical domain is established using the morphing technique, and the template trajectory mapping method in the parametric domain is given. Secondly, the clean-up boundary of the impeller channel is determined in the parametric domain, and the quasi-triangular template trajectory of the impeller channel is defined. Finally, taking a certain type of impeller as an example, the quasi-triangular tool path of the impeller channel is calculated, and the tool path calculation time of this method is compared with that of the traditional isometric offset method. The result shows that the computational efficiency is improved by 45% with this method, which provides a new method for the rapid acquisition of NC machining tool path for impeller channels. In addition, the simulation and actual machining are carried out, the results show that the shape of actual cutting traces on the surface of the impeller channel is quasi-triangular, showing that this method is effective and feasible.

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Lakshmanan, M., P. S. Mallick, and L. Nithyanandan. "Joint Timing Synchronization and Channel Estimation Using Perfect Sequence in Uplink Time Domain Synchronous OFDMA." International Journal of Electronics and Telecommunications 62, no. 3 (September 1, 2016): 225–29. http://dx.doi.org/10.1515/eletel-2016-0030.

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AbstractTime Domain Synchronous Orthogonal Frequency Division Multiple Access (TDS-OFDMA) is used in mobile broadband wireless access scheme in uplink transmission. This leads to multiple user interference due to timing offset and frequency offset. In this paper, the effect of timing offset and channel estimation in mobile broadband system is analysed. Time-space two dimensional structure is used in TDS-OFDMA and perfect sequence is used for guard interval to achieve perfect timing synchronization and channel estimation for each user. Simulations are performed for timing synchronization and channel estimation using perfect sequence under Urban channel, Indoor Office B channel and HIPER LAN-A channel. Simulation results show that the timing synchronization is achieved and channel estimation performance using perfect sequence is better than CAZAC and PN Sequences.

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Sakaue, Taichi, Chang-Jun Ahn, Tatsuya Omori, and Ken-Ya Hashimoto. "Time Domain Replica Signal Based Interference Compensation for SP-MIMO/OFDM with Large Delay Spread Channel." International Journal of Distributed Systems and Technologies 5, no. 4 (October 2014): 1–17. http://dx.doi.org/10.4018/ijdst.2014100101.

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In mobile communications, MIMO-OFDM transmission performance suffers severe degradation caused by the large delay spread channel greater than guard interval (GI). This is because the excess delay results in considerable inter-symbol interference (ISI) between adjacent symbols and inter-carrier-interference (ICI) among subcarrier in the same symbol. In case of scattered pilot (SP), the interference of pilot signals causes the deterioration of channel estimation. To mitigate this problem, in this paper, we propose the interference compensation scheme using the time domain replica signals. We make the time domain replica signals from detected signals and the excess channel impulse responses over GI. After compensation of the time domain replica signals and the received signals, we recalculate the channel state information (CSI) and the CSI is updated. Finally, we carry out the channel compensation with updated CSI for obtaining accurate compensated signals.

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Li, Shun Xian. "An Improved Channel Estimation Method in OFDM System." Applied Mechanics and Materials 347-350 (August 2013): 1646–52. http://dx.doi.org/10.4028/www.scientific.net/amm.347-350.1646.

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In this paper, we will focus on channel estimation (CE) in orthogonal frequency-division multiplexing (OFDM) systems. The time-varying (TV) channelsare modeled by a basis expansion model (BEM). Due to the time-variation, the channel matrix in the frequency domain is no longer diagonal, but approximately banded.We use a pilot-aided algorithm for estimation of rapidly varying wireless channels in OFDM systems. Theperforms is goodwhen the channels vary on the scale of a single OFDM symbol duration, which occurs in mobile communication scenarios such as WiMAX, WAVE, and DVB-T.We recover Fourier coefficients of the channel taps by the pilot information.We then estimate the BEM coefficients of the channel taps from their respective Fourier coefficients using a recently developed inverse reconstruction method.We compare some BEM models in inverse methodsto find out the best ones in certain conditions.

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Jiang, Xialin, Wei Su, and En Cheng. "Combined Hybrid DFE and CCK Remodulator for Medium-Range Single-Carrier Underwater Acoustic Communications." Wireless Communications and Mobile Computing 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/4096061.

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Advanced modulation and channel equalization techniques are essential for improving the performance of medium-range single-carrier underwater acoustic communications. In this paper, an enhanced detection scheme, hybrid time-frequency domain decision feedback equalizer (DFE) combined with complementary code keying (CCK) remodulator, is presented. CCK modulation technique provides strong tolerance to intersymbol interference caused by multipath propagation in underwater acoustic channels. The conventional hybrid DFE, using a frequency domain feedforward filter and a time domain feedback filter, provides good performance along with low computational complexity. The error propagation in the feedback filter, caused by feedbacking wrong decisions prior to CCK demodulation, may lead to great performance degradation. In our proposed scheme, with the help of CCK coding gain, more accurate remodulated CCK chips can be used as feedback. The proposed detection scheme is tested by the practical ocean experiments. The experimental results show that the proposed detection scheme ensures robust communications over 10-kilometre underwater acoustic channels with the data rate at 5 Kbits/s in 3 kHz of channel bandwidth.

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