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The post-reionization $(z \le 6)$ neutral hydrogen (HI) 21-cm intensity mapping signal holds the potential to probe the large scale structures, study the expansion history and constrain various cosmological parameters. Here we apply the…

Extending terrestrial networks into low-altitude airspace is a practical way to support aerial services, and accurate low-altitude radio maps are essential for characterizing terrestrial base station (BS) coverage and guiding system design.…

Signal Processing · Electrical Eng. & Systems 2026-05-25 Bowen Li , Haotian Zhang , Mu Jia , Junting Chen , Nikolaos Pappas

The channel estimation problem has been widely discussed in traditional reconfigurable intelligent surface assisted multiple-input multiple-output. However, solutions for channel estimation adapted to beyond diagonal RIS need further study,…

Signal Processing · Electrical Eng. & Systems 2024-12-05 Gilderlan T de Araujo , Andre L. F. de Almeida

The expansion of telecommunications incurs increasingly severe crosstalk and interference, and a physical layer cognitive method, called blind source separation (BSS), can effectively address these issues. BSS requires minimal prior…

Signal Processing · Electrical Eng. & Systems 2023-03-22 Weipeng Zhang , Alexander Tait , Chaoran Huang , Thomas Ferreira de Lima , Simon Bilodeau , Eric Blow , Aashu Jha , Bhavin J. Shastri , Paul Prucnal

Beyond diagonal reconfigurable intelligent surface (BD-RIS) architectures offer superior beamforming gain over conventional diagonal RISs. However, the channel estimation overhead is the main hurdle for reaping the above gain in practice.…

Signal Processing · Electrical Eng. & Systems 2026-02-25 Rui Wang , Junyuan Gao , Shuowen Zhang , Bruno Clerckx , Liang Liu

We extend 21CMMC, a Monte Carlo Markov Chain sampler of 3D reionisation simulations, to perform parameter estimation directly on 3D light-cones of the cosmic 21cm signal. This brings theoretical analysis closer to the tomographic 21-cm…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-11 Bradley Greig , Andrei Mesinger

In this paper, the design, realization, and demonstration of a broadband millimeter-wave imaging system based on the synthetic aperture radar technique (SAR) are discussed. The proposed system, operating within the frequency range of…

Applied Physics · Physics 2022-06-01 Fahimeh Sepehripour , Ahmad Shafiei Alavijeh , Mohammad Fakharzadeh , Amin Khavasi

The 21-cm signal from the Epoch of Reionization (EoR) is a powerful probe of the evolution of the Universe. However, accurate measurements of the EoR signal from radio interferometric observations are sensitive to efficient foreground…

Instrumentation and Methods for Astrophysics · Physics 2025-09-23 Madhurima Choudhury , Jonathan C. Pober

The HI 21cm absorption line is masked by bright foregrounds and systematic distortions that arise due to the chromaticity of the antenna used to make the observation coupling to the spectral inhomogeneity of these foregrounds. We…

Instrumentation and Methods for Astrophysics · Physics 2021-11-12 Dominic Anstey , Eloy de Lera Acedo , Will Handley

This paper investigates the broadband channel estimation (CE) for intelligent reflecting surface (IRS)-aided millimeter-wave (mmWave) massive MIMO systems. The CE for such systems is a challenging task due to the large dimension of both the…

Information Theory · Computer Science 2023-07-14 Ziwei Wan , Zhen Gao , Mohamed-Slim Alouini

Cosmic Microwave Background experiments from COBE to Planck, have launched cosmology into an era of precision science, where many cosmological parameters are now determined to the percent level. Next generation telescopes, focussing on the…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-26 Claude J. Schmit , Alan F. Heavens , Jonathan R. Pritchard

A number of radio interferometers are currently being planned or constructed to observe 21 cm emission from reionization. Not only will such measurements provide a detailed view of that epoch, but, since the 21 cm emission also traces the…

Radio interferometric data are used to estimate the sky brightness distributions in radio frequencies. Here we focus on estimators of the large-scale structure and the power spectrum of the sky brightness distribution inferred from radio…

Instrumentation and Methods for Astrophysics · Physics 2019-04-17 Prasun Dutta , Meera Nandakumar

Observing the Epoch of Reionisation using 21cm radio interferometry has proven to be a challenging task. Extraction of the extremely faint redshifted signal is complicated by the presence of bright foregrounds, radio frequency interference…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-30 Sohini Dutta , Philip Bull , Jacob Burba , Michael J. Wilensky , Zheng Zhang , Ainulnabilah Nasirudin

In a previous paper we presented the results of applying machine learning to classify whether an HI 21-cm absorption spectrum arises in a source intervening the sight-line to a more distant radio source or within the host of the radio…

Instrumentation and Methods for Astrophysics · Physics 2021-07-14 S. J. Curran

In this paper, we investigate channel estimation for a large intelligent surface (LIS) aided multiple-input multiple-output (MIMO) communication system. Due to the close proximity of communication devices and LIS terminal, the desired…

Information Theory · Computer Science 2020-06-02 Jawad Mirza , Bakhtiar Ali

Aiming to fill a crucial gap in our observational knowledge of the early Universe, experiments around the world continue to attempt to verify the claimed detection of the redshifted 21-cm signal from Cosmic Dawn by the EDGES experiment.…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-15 B. McKinley , C. M. Trott , M. Sokolowski , R. B. Wayth , A. Sutinjo , N. Patra , J. Nambissan T. , D. C. X. Ung

While limited to low spatial resolution, the next generation low-frequency radio interferometers that target 21 cm observations during the era of reionization and prior will have instantaneous fields-of-view that are many tens of square…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 M. G. Santos , L. Ferramacho , M. B. Silva , A. Amblard , A. Cooray

We address the localization of a reconfigurable intelligent surface (RIS) for a single-input single-output multi-carrier system using bi-static sensing between a fixed transmitter and a fixed receiver. Due to the deployment of RISs with a…

Signal Processing · Electrical Eng. & Systems 2022-07-11 Reza Ghazalian , Kamran Keykhosravi , Hui Chen , Henk Wymeersch , Riku Jäntti

Reconfigurable intelligent surfaces (RISs) are one of the foremost technological enablers of future wireless systems. They improve communication and localization by providing a strong non-line-of-sight path to the receiver. In this paper,…

Signal Processing · Electrical Eng. & Systems 2022-04-26 Kamran Keykhosravi , Henk Wymeersch