Topic
Adaptive beamformer
About: Adaptive beamformer is a research topic. Over the lifetime, 4934 publications have been published within this topic receiving 93100 citations.
Papers published on a yearly basis
Papers
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TL;DR: A constrained adaptive filtering strategy based on conjugate gradient and set-membership techniques is presented for adaptive beamforming and two time-varying bounding schemes are introduced to measure the quality of the parameters that could be included in the parameter space.
Abstract: In this work, a constrained adaptive filtering strategy based on conjugate gradient (CG) and set-membership techniques is presented for adaptive beamforming. A constraint on the magnitude of the array output is imposed to derive an adaptive algorithm that performs data-selective updates when calculating the beamformer's parameters. A linearly constrained minimum variance optimisation problem is consider with the bounded constraint based on this strategy and propose a CG-type algorithm for implementation. The proposed algorithm has data-selective updates, a variable forgetting factor and performs one iteration per update to reduce the computational complexity. The updated parameters construct a space of feasible solutions that enforce the constraints. The authors also introduce two time-varying bounding schemes to measure the quality of the parameters that could be included in the parameter space. A comprehensive complexity and performance analysis between the proposed and existing algorithms are provided. Simulations are performed to show the enhanced convergence and tracking performance of the proposed algorithm as compared with existing techniques.
22 citations
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TL;DR: In this article, a reconfigurable intelligent surface (RIS) is proposed to aid wireless communications to overcome path loss and shadowing issues, by using a compressive sensing-based adaptive beamforming algorithm.
Abstract: Recently, the fifth generation of cellular mobile communications (5G) network has been deployed and become pervasive. 5G offers a significant increase in terms of bandwidth and data rate compared to the previous generations. In addition, new technologies such as millimeter-wave (mmWave) technology and massive MIMO (mMIMO), have been proposed to meet the demand. However, some inevitable challenges still exist. In mmWave frequency, path loss and shadowing become more severe due to the radio electromagnetic (EM) wave characteristics. In this paper, we propose the utilization of reconfigurable intelligent surface (RIS) to aid wireless communications to overcome path loss and shadowing issues, by using a compressive sensing-based adaptive beamforming algorithm. To validate the theory, hypothesis, and simulation results, we have designed, fabricated, and conducted experiments with a 1-bit RIS testbed. The results show that the bit error rate (BER) and signal-to-noise ratio (SNR) of the received signal are significantly improved when the proposed RIS is employed. Further, we have also demonstrated a video streaming application aided by the proposed RIS as one of the potential RIS deployment scenarios.
22 citations
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TL;DR: In this article, a multirate/sub-band adaptive beamforming based on QMF banks is presented, in terms of convergence speed and cancellation performance, over full-band beamforming.
Abstract: A novel multirate/sub-band adaptive beamformer based on QMF banks is presented. Computer simulations of the new technique in a BPSK, DS-SSMA mobile radio system demonstrate its superiority, in terms of convergence speed and cancellation performance, over full-band beamforming.
21 citations
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TL;DR: In this article, a multibeam optical beamformer capable of controlling a phased-array antenna in receive/transmit mode is proposed, which can be programmed to sweep the antenna aperture following an independent angular sequence for each radiofrequency (RF) beam.
Abstract: A multibeam optical beamformer capable of controlling a phased-array antenna in receive/transmit mode is proposed. The processor can be programmed to sweep the antenna aperture following an independent angular sequence for each radio-frequency (RF) beam. A two-beam two-channel 3-bit version of the beamformer has been experimentally demonstrated. The optical beamformer processes two independent RF beams, for eight different angular directions, and it is based on a binary array of three delay lines. Each delay line is composed of four fiber Bragg gratings whose center wavelengths are channels 30 to 33 of the International Telecommunications Union (ITU) grid. Measurements are performed for both receive and transmit modes and for RF values between 0.5 and 1.5 GHz. We present beam-pattern results showing the squint-free performance of the beamformer within this frequency range. In the transmit mode, two RF beams are steered and characterized for a broadside target position. In the receive mode, the beamformer performance is characterized by detecting two simultaneous RF beams.
21 citations