2172 research outputs found
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Deaf People and Their Sign Language in Japan － Establishing Sign Language in Deaf Education －
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Investigation of the neural mechanisms in illusory glare perception
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Analog Self-Interference Cancellation Using Auxiliary Transmitter Considering IQ Imbalance and Amplifier Nonlinearity
Get PDFIn-band full-duplex communication, which transmits and receives simultaneously on the same frequency, causes self-interference (SI). In this paper, to cancel SI present in the radio frequency (RF) domain, we propose a novel nonlinear SI cancellation approach using an auxiliary transmitter which is effective in the presence of IQ imbalance and nonlinear distortion. The proposed approach estimates the local transceiver channel by using a time-domain least squares method and creates a signal for SI cancellation based on estimation results and a finite impulse response filter, whose coefficients are derived in this paper. Additionally, we theoretically calculate the SI cancellation limit of the proposed approach. Information about the SI cancellation limit due to phase noise is important for meeting SI cancellation requirements and being able to compare the effects of RF impairments such as IQ imbalance and nonlinear distortion. From simulation results, we show that the proposed approach outperforms the conventional approach and the case of using a general adaptive algorithm for the proposed approach. Furthermore, the SI cancellation limit is improved by adjusting the propagation delay of the SI signal and the canceling signal in addition to sharing one local oscillator in the local transceiver.journal articl
Iterative Nonlinear Self-Interference Cancellation for In-Band Full-Duplex Wireless Communications Under Mixer Imbalance and Amplifier Nonlinearity
Get PDFThis paper presents an iterative estimation and cancellation technique for nonlinear in-band full-duplex transceivers with IQ imbalances and amplifier nonlinearities. The estimation process of the proposed scheme consists of three stages, namely, the channel response estimation, IQ imbalance estimation, and power amplifier and low-noise amplifier (LNA) nonlinearities estimation. For the estimation of the parameters and improvement of the accuracy, distortions are compensated by cancellation or inversion with the latest estimated parameters. On the one hand, the channel response is estimated on the time domain; on the other hand, the IQ imbalance and nonlinearities are estimated on the frequency domain for a more straightforward estimation and superior accuracy. In the cancellation process of the proposed scheme, the received signal is compensated with the estimated parameters of the LNA and receiver IQ imbalance before cancellation because the desired signal is received with a high-power self-interference and is distorted by the radiofrequency receiver impairments. Simulation results show that the proposed technique can achieve higher cancellation performance compared with the Hammerstein canceller when the LNA is saturated by the self-interference. Additionally, the performance of the proposed canceller converges much faster than that of the Hammerstein canceller.journal articl
Load Swing and Skew Vibration Suppression and Excitation Controls of Crane Systems
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Evaluation of Economic Impacts for Sustainable Tourism: An Integrated Approach
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Weighted Least Squares with Orthonormal Polynomials and Numerical Integration for Estimation of Memoryless Nonlinearity
Get PDFThe nonlinearity of amplifiers is one of the major impairments in wireless communications. In this letter, we propose a novel estimation method for the memoryless nonlinearity of amplifiers using weighted least squares and provide its theoretical error analysis on complex Gaussian signals. In the proposed method, the input signal and weight value are obtained via numerical integration formulas. Simulation results show that the proposed method can achieve a sufficiently low reconstruction error with 10 measurement samples on the estimation of the 13th-order nonlinearity. In addition, the simulation and theoretical results are consistent with each other.journal articl
Catalytic Intramolecular Carbene Transfer Reactions into σ and π Bonds
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