Intelligent reflecting surface (IRS) is a promising technology to reconfigure wireless channels, which brings new degree of freedom for the design future networks. This article proposes three-dimensional (3D) system architecture enabled by aerial IRS (AIRS). Compared conventional terrestrial IRS, AIRS enjoys more deployment flexibility as well wider-view signal reflection, thanks its high altitude and thus likelihood establishing line-of-sight (LoS) links with ground source/destination...

Wireless communications with extremely large-scale array (XL-array) correspond to systems whose antenna sizes are so large that conventional modeling assumptions, such as uniform plane wave (UPW) impingement, no longer valid. This paper studies the mathematical and performance analysis of XL-array communications. By deviating from approach treats elements sizeless points, we explicitly model their physical area/aperture, which enables a unified for classical discrete arrays emerging active...

Extremely large-scale multiple-input multiple-output (XL-MIMO) is a promising technology for the sixth-generation (6G) mobile communication networks. By significantly boosting antenna number or size to at least an order of magnitude beyond current massive MIMO systems, XL-MIMO expected unprecedentedly enhance spectral efficiency and spatial resolution wireless communication. The evolution from not simply increase in array size, but faces new design challenges, terms near-field channel...

This paper proposes a new three dimensional (3D) networking architecture enabled by aerial intelligent reflecting surface (AIRS) to achieve panoramic signal reflection from the sky. Compared conventional terrestrial IRS, AIRS not only enjoys higher deployment flexibility, but also is able 360° full-angle and requires fewer reflections in general due its likelihood of having line-of-sight (LoS) links with ground nodes. We focus on problem maximize worst-case signal-to-noise ratio (SNR) given...

This paper considers a new wireless information surveillance scenario, where legitimate monitor tries to eavesdrop on the suspicious messages sent by an unmanned aerial vehicle aided transmitter. By using characteristic of system, we propose effective proactive jamming scheme maximize achievable eavesdropping rate. A successive convex approximation based iterative algorithm is first developed solve original non-convex optimization problem. Based this result, rate maximization problem then...

This letter studies the near-field modeling and performance analysis for multi-user extremely large-scale multiple-input multiple-output (XL-MIMO) communication. With spherical wavefront phase modeling, by taking into account variations of signal amplitude projected aperture across array elements, three typical beamforming schemes are investigated, namely maximal-ratio combining (MRC), zero-forcing (ZF), minimum mean-square error (MMSE) beamforming. Compared to existing uniform plane wave...

Extremely large-scale multiple-input multiple-output (XL-MIMO) communications correspond to systems whose antenna size is so large that conventional assumptions, such as uniform plane wave (UPW) impingement, are no longer valid. This paper studies the channel modelling and performance analysis of XL-MIMO communication based on generic spherical wavefront propagation model. First, for single-user uplink/downlink with optimal maximum ratio combining/transmission (MRC/MRT), we rigorously derive...

This letter proposes a novel broadband transmission technology, termed <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">delay alignment modulation</i> (DAM), which enables the low-complexity equalization-free single-carrier communication, yet without suffering from inter-symbol interference (ISI). The key idea of DAM is to deliberately introduce appropriate delays for information-bearing symbols at transmitter side, so that after propagating...

This letter studies a new array architecture, termed as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">modular extremely large-scale</i> (XL-array), for which large number of elements are arranged in modular manner. Each module consists moderate and the modules regularly with inter-module spacing typically much larger than signal wavelength to cater actual mounting structure. We study mathematical modelling conduct performance analysis...

The evolution of mobile communication networks has always been accompanied by the advancement inter-symbol interference (ISI) mitigation techniques, from equalization in second-generation (2G), spread spectrum and RAKE receiver third generation (3G), to orthogonal frequency-division multiplexing (OFDM) fourth-generation (4G) fifth-generation (5G). Looking forward towards sixth-generation (6G), exploiting high spatial resolution brought large antenna arrays multi-path sparsity millimeter wave...

This paper investigates the wireless communication with a novel architecture of antenna arrays, termed modular extremely large-scale array (XL-array), where elements an large number/size are regularly mounted on shared platform both horizontally and vertically interlaced modules. Each module consists moderate/flexible number inter-element distance typically in order signal wavelength, while different modules separated by relatively inter-module for convenience practical deployment. By...

Delay alignment modulation (DAM) is a promising technology to achieve inter-symbol interference (ISI)-free single-carrier communication, by leveraging <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">delay compensation</i> and xmlns:xlink="http://www.w3.org/1999/xlink">path-based beamforming</i> , rather than the conventional channel equalization or multi-carrier transmission. In particular, when there exist few strong time-dispersive paths,...

<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Delay alignment modulation</i> (DAM) is an emerging technique for achieving inter-symbol interference (ISI)-free wideband communications using spatial-delay processing, without relying on channel equalization or multi-carrier transmission. However, existing works DAM only consider multiple-input single-output (MISO) communication systems and assume time-invariant channels. In this paper, by...

Wireless communications with extremely large-scale array (XL-array) correspond to systems whose antenna sizes are so large that conventional modelling assumptions, such as uniform plane wave (UPW) impingement, longer valid. This paper studies the mathematical and performance analysis of XL-array communications. By deviating from approach treats elements sizeless points, we explicitly model their physical area/aperture, which enables a unified for classical discrete arrays emerging continuous...

Intelligent reflecting surface (IRS) is a promising technology for wireless communications, thanks to its potential capability engineer the radio environment. However, in practice, such an envisaged benefit attainable only when passive IRS of sufficiently large size, which conventional uniform plane wave (UPW)-based channel model may become inaccurate. In this paper, we pursue new modelling and performance analysis communications with extremely large-scale (XL-IRS). By taking into account...

Delay alignment modulation (DAM) is a novel wideband communication technique, which exploits the high spatial resolution and multi-path sparsity of millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) systems to mitigate inter-symbol interference (ISI), without relying on conventional techniques like channel equalization or multi-carrier transmission. In this paper, we extend DAM technique multi-user mmWave MIMO systems. We first provide asymptotic analysis by showing that...

Extremely large-scale multiple-input multiple-output (XL-MIMO) is a promising technology for the sixth-generation (6G) mobile communication networks. By significantly boosting antenna number or size to at least an order of magnitude beyond current massive MIMO systems, XL-MIMO expected unprecedentedly enhance spectral efficiency and spatial resolution wireless communication. The evolution from not simply increase in array size, but faces new design challenges, terms near-field channel...

Intelligent reflecting surface (IRS) is an emerging technology for wireless communications, thanks to its powerful capability engineer the radio environment. However, in practice, this benefit attainable only when passive IRS of sufficiently large size, which conventional uniform plane wave (UPW)-based far-field model may become invalid. In paper, we pursue a near-field modelling and performance analysis communications with extremely large-scale (XL-IRS). By taking into account directional...

Abstract This paper studies a new wireless surveillance scenario, where legitimate monitor attempts to eavesdrop on the dubious messages forwarded by an unmanned aerial vehicle (UAV)-aided suspicious relay. Specifically, we consider two relaying protocols commonly used UAV-aided relay, namely, amplify-and-forward (AF) and decode-and-forward (DF). For each protocol, maximize average effective eavesdropping rate optimizing monitor’s jamming power allocation, subject constraint. The optimal...

Extremely large-scale multiple-input multiple-output (XL-MIMO) communications correspond to systems whose antenna size is so large that conventional assumptions, such as uniform plane wave (UPW) impingement, are no longer valid. This paper studies the channel modelling and performance analysis of XL-MIMO communication based on generic spherical wavefront propagation model. First, for single-user uplink/downlink with optimal maximum ratio combining/transmission (MRC/MRT), we rigorously derive...

This paper proposes a new three-dimensional (3D) wireless passive relaying system enabled by aerial IRS (AIRS). Compared to the conventional terrestrial IRS, AIRS enjoys more deployment flexibility as well wider-range signal reflection, thanks its high altitude and thus likelihood of establishing line-of-sight (LoS) links with ground source/destination nodes. Specifically, we aim maximize worst-case signal-to-noise ratio (SNR) over all locations in target area jointly optimizing transmit...

Passive metal reflectors for communication enhancement have appealing advantages such as ultra low cost, zero energy expenditure, maintenance-free operation, long life span, and full compatibility with legacy wireless systems. To unleash the potential of passive communications, this paper proposes a new reflector architecture, termed flexible (FR), enabling adjustment beamforming direction via FR placement rotation optimization. We consider multi-FR aided area coverage aim to maximize...