The Experts below are selected from a list of 51831 Experts worldwide ranked by ideXlab platform
Kazuo Hotate - One of the best experts on this subject based on the ideXlab platform.
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simulation and experiment for verifying intensity Modulation Scheme in brillouin optical correlation domain reflectometry
Conference on Lasers and Electro-Optics, 2012Co-Authors: Sitthipong Manotham, Masato Kishi, Kazuo HotateAbstract:Intensity Modulation Scheme in Brillouin optical correlation domain reflectometry is verified both by simulation and experiment. The simulation results are in good agreement with the experiments. The optimized waveform for the Modulation is clarified to be effective.
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measurement range enlargement in brillouin optical correlation domain reflectometry based on double Modulation Scheme
Optics Express, 2010Co-Authors: Yosuke Mizuno, Kazuo HotateAbstract:We have demonstrated a double-Modulation Scheme to enlarge the measurement range of Brillouin optical correlation-domain reflectometry for fiber-optic distributed strain sensing. In this Scheme, the frequency of the laser output is simultaneously modulated with two different frequencies. In the experiment, 53-cm resolution and 1.5-km measurement range were simultaneously obtained. Furthermore, 27-cm resolution and 1.5-km measurement range were also simultaneously achieved when a noise-floor compensation technique was employed.
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measurement range enlargement in brillouin optical correlation domain reflectometry based on double Modulation Scheme
20th International Conference on Optical Fibre Sensors, 2009Co-Authors: Yosuke Mizuno, Kazuo HotateAbstract:We have demonstrated a double-Modulation Scheme to enlarge the measurement range of Brillouin optical correlationdomain reflectometry (BOCDR) for fiber-optic distributed strain sensing. In this Scheme, the frequency of the laser output is simultaneously modulated with two different frequencies. A resolution of 27 cm was achieved with 1.5-km measurement range when a noise-floor compensation technique was used.
Mamoru Sawahashi - One of the best experts on this subject based on the ideXlab platform.
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optimum adaptive Modulation and channel coding Scheme for frequency domain channel dependent scheduling in ofdm based evolved utra downlink
IEICE Transactions on Communications, 2009Co-Authors: Nobuhiko Miki, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi, Masao NakagawaAbstract:In the Evolved UTRA (UMTS Terrestrial Radio Access) downlink, Orthogonal Frequency Division Multiplexing (OFDM) based radio access was adopted because of its inherent immunity to multipath interference and flexible accommodation of different spectrum arrangements. This paper presents the optimum adaptive Modulation and channel coding (AMC) Scheme when resource blocks (RBs) is simultaneously assigned to the same user when frequency and time domain channel-dependent scheduling is assumed in the downlink OFDMA radio access with single-antenna transmission. We start by presenting selection methods for the Modulation and coding Scheme (MCS) employing mutual information both for RB-common and RB-dependent Modulation Schemes. Simulation results show that, irrespective of the application of power adaptation to RB-dependent Modulation, the improvement in the achievable throughput of the RB-dependent Modulation Scheme compared to that for the RB-common Modulation Scheme is slight, i.e., 4 to 5%. In addition, the number of required control signaling bits in the RB-dependent Modulation Scheme becomes greater than that for the RB-common Modulation Scheme. Therefore, we conclude that the RB-common Modulation and channel coding rate Scheme is preferred, when multiple RBs of the same coded stream are assigned to one user in the case of single-antenna transmission.
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optimum adaptive Modulation and channel coding Scheme for frequency domain channel dependent scheduling in ofdm based evolved utra downlink
Wireless Communications and Networking Conference, 2007Co-Authors: Nobuhiko Miki, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru SawahashiAbstract:In the evolved UTRA (UMTS terrestrial radio access) downlink, orthogonal frequency division multiplexing (OFDM) based radio access was adopted because of its inherent immunity to multipath interference and flexible accommodation of different spectrum arrangements. This paper presents the optimum adaptive Modulation and channel coding (AMC) Scheme for simultaneously assigned resource blocks (RBs) for the same user when frequency and time domain channel-dependent scheduling is used in the downlink OFDMA radio access with single-antenna transmission. Theoretical analyses and simulation results show that, irrespective of the application of power adaptation to RB-dependent Modulation, the improvement in the achievable throughput of the RB-dependent Modulation Scheme compared to that for the RB-common Modulation Scheme is slight, i.e., 4 to 5%. In addition, the number of required control signaling bits in the RB-dependent Modulation Scheme becomes greater than that for the RB-common Modulation Scheme. Therefore, the authors conclude that the RB-common Modulation and channel coding rate Scheme is preferred, when multiple RBs of the same coded stream are assigned to one user in the case of single-antenna transmission.
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comparisons of 16qam Modulation Schemes considering papr for single carrier fdma radio access in evolved utra uplink
International Symposium on Spread Spectrum Techniques and Applications, 2006Co-Authors: Teruo Kawamura, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru SawahashiAbstract:This paper compares the achievable packet error rate and throughput performance levels of 16QAM Modulation Schemes considering the peak-to-average power ratio for single-carrier frequency division multiple access (SC-FDMA) in the Evolved UTRA uplink. Simulation results show that the effective required average received signal energy per symbol-to-noise power spectrum density ratio (Es/N0) including the cubic metric (CM) of the (8, 8) star 16QAM Modulation Scheme is decreased by approximately 0.8 dB compared to that of the square 16QAM Modulation Scheme using Turbo coding with the coding rate of R = 1/3 in the six-ray Typical Urban channel model, when the amplitude ratio between the inner and outer ring, Rradius, is equal to 1.2. The results also show that although the star 16QAM Modulation Scheme reduces the effective required average received Es/N0 including the CM compared to the square 16QAM Modulation Scheme, this merit is concealed by the application of low Modulation Schemes such as QPSK and 8PSK when adaptive Modulation and coding is applied. Therefore, we conclude that the square 16QAM Modulation Scheme is an appropriate candidate for SC-FDMA radio access in the Evolved UTRA uplink.
Frede Blaabjerg - One of the best experts on this subject based on the ideXlab platform.
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addressing the unbalance loading issue in multi drive systems with a dc link Modulation Scheme for harmonic reduction
Applied Power Electronics Conference, 2016Co-Authors: Yongheng Yang, Pooya Davari, Firuz Zare, Frede BlaabjergAbstract:Concerning cost, volume, and efficiency, Adjustable Speed Drive (ASD) systems are commonly employed with diode rectifiers or Silicon Controlled Rectifiers (SCR) as the front-ends (i.e., ac-dc converters). Apart from low cost, small volume, and high reliability, harmonic currents are significantly produced at the grid side by the rectification apparatus (i.e., diode rectifiers or SCR). As a simple strategy, the phase-shifted current control can be applied to the SCR-fed drive systems, where the input currents for the SCR are phase-shifted in such a way to cancel out the harmonics of interest (e.g., the 5th order harmonic). However, this solution is effective only when same amounts of currents are drawn by the rectifiers. Unfortunately, in practice, the loading is different among the parallel drive systems, leading to degradation in the harmonic mitigation. In this paper, unequal loading conditions in multi-drive systems are thus addressed. A load-adaptive Scheme by means of varying the dc-link voltage is proposed, where a unified dc-link current Modulation Scheme is also employed in the dc-link. The proposed load-adaptive Scheme can ensure that the rectified currents (i.e., rectifier output currents) are equal, and thus the harmonic reduction enabled by the phase-shifted current control is enhanced. The principle of the proposed method is demonstrated on a two-drive system consisting of a diode rectifier and a SCR. Experimental tests have validated the effectiveness of the proposed Scheme in terms of harmonic mitigation for multiple parallel ASD systems.
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a multipulse pattern Modulation Scheme for harmonic mitigation in three phase multimotor drives
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2016Co-Authors: Pooya Davari, Yongheng Yang, Firuz Zare, Frede BlaabjergAbstract:A continuous improvement of power electronics technology has widely increased the applications of adjustable speed motor drives in many areas. Beyond the control flexibility, the power electronics devices (e.g., diode rectifiers) are also the main harmonic source to the grid due to their nonlinearity, which thus deteriorates the power grid quality and also lowers the conversion efficiency. Both degradations are apt to occur in motor drive applications. At present, many industrial drives are equipped with three-phase diode rectifiers and employ passive filtering techniques on the ac or the dc side of the rectifier. In such topologies, it is difficult to implement the prior-art harmonic control strategies. Moreover, the total cost and complexity has become the main obstacle for these harmonic elimination approaches in multiple drive systems. Therefore, in this paper, a new cost-effective harmonic mitigation approach has been proposed for multiple drives. The proposed approach can control the generated current harmonics by benefiting of the nonlinearity of the drive units and through a novel current Modulation Scheme. The obtained results at the simulation and the experimental level validate the effectiveness of the proposed approach.
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a dc link Modulation Scheme with phase shifted current control for harmonic cancellations in multidrive applications
IEEE Transactions on Power Electronics, 2016Co-Authors: Yongheng Yang, Pooya Davari, Firuz Zare, Frede BlaabjergAbstract:This letter proposes a harmonic mitigation strategy to cancel out current harmonics induced by the front-end rectifiers in multidrive systems, which consist of diode rectifiers, silicon-controlled rectifiers (SCR), and boost converters in the dc-link. The proposed strategy is a combination of a new dc-link Modulation Scheme with a phase-shifted current control enabled by the SCR. The dc-link current Modulation Scheme is implemented by adding and subtracting specific Modulation levels, which makes the total currents drawn from the grid “multilevel,” resulting in an improved current quality. Simulations and experiments have validated the effectiveness of the proposed harmonic mitigation solution for multidrive systems.
Yosuke Mizuno - One of the best experts on this subject based on the ideXlab platform.
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first demonstration of brillouin optical correlation domain reflectometry based on external Modulation Scheme
Japanese Journal of Applied Physics, 2019Co-Authors: Kohei Noda, Heeyoung Lee, Yosuke Mizuno, Kentaro NakamuraAbstract:We demonstrate basic operation of Brillouin optical correlation-domain reflectometry (BOCDR) based on an external Modulation Scheme, which can mitigate three demerits of a conventional direct Modulation Scheme. A 0.8 m long strain in a 2.8 m long silica fiber is successfully detected in a distributed manner. This Scheme can be employed not only in BOCDR but also in Brillouin optical correlation-domain analysis.
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measurement range enlargement in brillouin optical correlation domain reflectometry based on double Modulation Scheme
Optics Express, 2010Co-Authors: Yosuke Mizuno, Kazuo HotateAbstract:We have demonstrated a double-Modulation Scheme to enlarge the measurement range of Brillouin optical correlation-domain reflectometry for fiber-optic distributed strain sensing. In this Scheme, the frequency of the laser output is simultaneously modulated with two different frequencies. In the experiment, 53-cm resolution and 1.5-km measurement range were simultaneously obtained. Furthermore, 27-cm resolution and 1.5-km measurement range were also simultaneously achieved when a noise-floor compensation technique was employed.
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measurement range enlargement in brillouin optical correlation domain reflectometry based on double Modulation Scheme
20th International Conference on Optical Fibre Sensors, 2009Co-Authors: Yosuke Mizuno, Kazuo HotateAbstract:We have demonstrated a double-Modulation Scheme to enlarge the measurement range of Brillouin optical correlationdomain reflectometry (BOCDR) for fiber-optic distributed strain sensing. In this Scheme, the frequency of the laser output is simultaneously modulated with two different frequencies. A resolution of 27 cm was achieved with 1.5-km measurement range when a noise-floor compensation technique was used.
Nobuhiko Miki - One of the best experts on this subject based on the ideXlab platform.
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optimum adaptive Modulation and channel coding Scheme for frequency domain channel dependent scheduling in ofdm based evolved utra downlink
IEICE Transactions on Communications, 2009Co-Authors: Nobuhiko Miki, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi, Masao NakagawaAbstract:In the Evolved UTRA (UMTS Terrestrial Radio Access) downlink, Orthogonal Frequency Division Multiplexing (OFDM) based radio access was adopted because of its inherent immunity to multipath interference and flexible accommodation of different spectrum arrangements. This paper presents the optimum adaptive Modulation and channel coding (AMC) Scheme when resource blocks (RBs) is simultaneously assigned to the same user when frequency and time domain channel-dependent scheduling is assumed in the downlink OFDMA radio access with single-antenna transmission. We start by presenting selection methods for the Modulation and coding Scheme (MCS) employing mutual information both for RB-common and RB-dependent Modulation Schemes. Simulation results show that, irrespective of the application of power adaptation to RB-dependent Modulation, the improvement in the achievable throughput of the RB-dependent Modulation Scheme compared to that for the RB-common Modulation Scheme is slight, i.e., 4 to 5%. In addition, the number of required control signaling bits in the RB-dependent Modulation Scheme becomes greater than that for the RB-common Modulation Scheme. Therefore, we conclude that the RB-common Modulation and channel coding rate Scheme is preferred, when multiple RBs of the same coded stream are assigned to one user in the case of single-antenna transmission.
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optimum adaptive Modulation and channel coding Scheme for frequency domain channel dependent scheduling in ofdm based evolved utra downlink
Wireless Communications and Networking Conference, 2007Co-Authors: Nobuhiko Miki, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru SawahashiAbstract:In the evolved UTRA (UMTS terrestrial radio access) downlink, orthogonal frequency division multiplexing (OFDM) based radio access was adopted because of its inherent immunity to multipath interference and flexible accommodation of different spectrum arrangements. This paper presents the optimum adaptive Modulation and channel coding (AMC) Scheme for simultaneously assigned resource blocks (RBs) for the same user when frequency and time domain channel-dependent scheduling is used in the downlink OFDMA radio access with single-antenna transmission. Theoretical analyses and simulation results show that, irrespective of the application of power adaptation to RB-dependent Modulation, the improvement in the achievable throughput of the RB-dependent Modulation Scheme compared to that for the RB-common Modulation Scheme is slight, i.e., 4 to 5%. In addition, the number of required control signaling bits in the RB-dependent Modulation Scheme becomes greater than that for the RB-common Modulation Scheme. Therefore, the authors conclude that the RB-common Modulation and channel coding rate Scheme is preferred, when multiple RBs of the same coded stream are assigned to one user in the case of single-antenna transmission.