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Hybrid analog-digital beamforming stands out as a key enabler for future communication systems with a massive number of antennas. In this paper, we investigate the hybrid precoder design problem for angle-of-departure (AoD) estimation,…

Information Theory · Computer Science 2024-10-24 Huiping Huang , Musa Furkan Keskin , Henk Wymeersch , Xuesong Cai , Linlong Wu , Johan Thunberg , Fredrik Tufvesson

Orbital angular momentum (OAM) has aroused a widespread interest in many fields, especially in telecommunications due to its potential for unleashing new capacity in the severely congested spectrum of commercial communication systems. Beams…

Applied Physics · Physics 2019-12-19 Rui Chen , Hong Zhou , Marco Moretti , Xiaodong Wang , Jiandong Li

We consider performance enhancement of asymmetrically-clipped optical orthogonal frequency division multiplexing (ACO-OFDM) and related optical OFDM schemes, which are variations of OFDM in intensity-modulated optical wireless…

Information Theory · Computer Science 2022-05-05 Xiaozhen Liu , Jing Zhou , Nuo Huang , Wenyi Zhang

The most common method to measure direct current high voltage (HV) down to the ppm-level is to use resistive high-voltage dividers. Such devices scale the HV into a range where it can be compared with precision digital voltmeters to…

Instrumentation and Detectors · Physics 2019-07-24 O. Rest , D. Winzen , S. Bauer , R. Berendes , J. Meisner , T. Thümmler , S. Wüstling , C. Weinheimer

We propose a new strategy for obtaining enhanced resolution (FWHM = 0.12 arcsec) deep optical images over a wide field of view. As is well known, this type of image quality can be obtained in principle simply by fast guiding on a small (D =…

Astrophysics · Physics 2009-10-31 N. Kaiser , J. L. Tonry , G. A. Luppino

In this paper, a novel amplitude-modulated continuous wave (AMCW) time-of-flight (ToF) scanning sensor based on digital-parallel demodulation is proposed and demonstrated in the aspect of distance measurement precision. Since…

Signal Processing · Electrical Eng. & Systems 2023-04-25 Sung-Hyun Lee , Wook-Hyeon Kwon , Yoon-Seop Lim , Yong-Hwa Park

By the use of homotopy perturbation method-Pad\'e (HPM-Pad\'e) technique, a new analytical approximation of luminosity distance in the flat universe is proposed, which has the advantage of significant improvement for accuracy in…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-20 Bo Yu , Jian-Chen Zhang , Tong-Jie Zhang , Tingting Zhang

Massive multiple-input multiple-output (MIMO) promises significantly higher performance relative to conventional multiuser systems. However, the promised gains of massive MIMO systems rely heavily on the accuracy of the absolute front-end…

Information Theory · Computer Science 2020-02-26 Guoda Tian , Harsh Tataria , Fredrik Tufvesson

The performance analysis of a novel optical modulation scheme is presented in this paper. The basic concept is to transmit signs of modulated optical orthogonal frequency division multiplexing (O-OFDM) symbols and absolute values of the…

Information Theory · Computer Science 2019-05-16 Yichen Li , Dobroslav Tsonev , Harald Haas

We propose and experimentally demonstrate a single-mode fiber length and dispersion measurement system based on a novel frequency-shifted asymmetric Sagnac interferometer incorporating an acousto-optic modulator (AOM). By sweeping the…

Optics · Physics 2009-11-13 Bing Qi , Andrew Tausz , Li Qian , Hoi-Kwong Lo

We developed a method to characterize arbitrary superpositions of light orbital angular momentum (OAM) with high fidelity by using astigmatic tomography and machine learning processing. In order to define each superposition unequivocally,…

In order to increase the measured phase of an atom interferometer and improve its sensitivity, researchers attempt to increase the enclosed space-time area using two methods: creating larger separations between the interferometer arms and…

In this paper, we propose two novel modulation concepts based on a simple maximum distance separable (MDS) code { and show that these concepts can achieve better error performance than index modulation (IM) and related schemes.} In the…

Signal Processing · Electrical Eng. & Systems 2021-08-11 Ferhat Yarkin , Justin P. Coon

Massive multiple input and multiple output (MIMO) systems with orthogonal frequency division multiplexing (OFDM) are foundational for downlink multi-user (MU) communication in future wireless networks, for their ability to enhance spectral…

Signal Processing · Electrical Eng. & Systems 2025-07-30 Erdeng Zhang , Shuntian Zheng , Sheng Wu , Haoge Jia , Zhe Ji , Ailing Xiao

We introduce and experimentally demonstrate a method for measuring at the same time the mean and the variance of the photonic orbital angular momentum (OAM) distribution in any paraxial optical field, without passing through the acquisition…

An interferometer has been used to measure the surface profile of generic object. Frequency scanning interferometry has been employed to provide unambiguous phase readings, to suppress etalon fringes, and to supersede phase-shifting. The…

Instrumentation and Detectors · Physics 2016-11-21 Marek Peca , Pavel Psota , Petr Vojtíšek , Vít Lédl

BOSS, the Baryon Oscillation Spectroscopic Survey, is a 5-year program to measure the absolute cosmic distance scale and expansion rate with percent-level precision at redshifts z<0.7 and z~2.5. BOSS uses the "standard ruler" provided by…

Cosmology and Nongalactic Astrophysics · Physics 2009-02-27 David Schlegel , Martin White , Daniel Eisenstein

Advances in analog-to-digital converter (ADC) technology have opened up the possibility to directly digitize wideband radio frequency (RF) signals, avoiding the need for analog down-conversion. In this work, we consider an orthogonal…

Information Theory · Computer Science 2019-07-17 Sven Jacobsson , Lise Aabel , Mikael Coldrey , Ibrahim Can Sezgin , Christian Fager , Giuseppe Durisi , Christoph Studer

The use of quantum resources can provide measurement precision beyond the shot-noise limit (SNL). The task of ab initio optical phase measurement---the estimation of a completely unknown phase---has been experimentally demonstrated with…

Massive MIMO is a variant of multiuser MIMO, where the number of antennas $M$ at the base-station is large, and generally much larger than the number of spatially multiplexed data streams to/from the users. It has been observed that in many…

Information Theory · Computer Science 2017-07-25 Saeid Haghighatshoar , Giuseppe Caire