Scattering Mechanisms and Modeling for Terahertz Wireless Communications

Ju, Shihao; Shah, Syed Hashim Ali; Javed, Muhammad Affan; Li, Jun; Palteru, Girish; Robin, Jyotish; Xing, Yunchou; Kanhere, Ojas; Rappaport, Theodore S.

doi:10.1109/icc.2019.8761205

Cited by 98 publications

(80 citation statements)

References 22 publications

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“…Narrow beam horn antennas with HPBWs of 10°, 7°, and 8°, which help to provide high angular resolution, were used at both the TX and RX at 28, 73, and 142 GHz, respectively. Incident angles of θ i = 10°, 30°, 60°, and 80°were chosen to measure the reflected and scattered power off drywall, with the incident angle varying from a small angle to a large angle with respect to a line normal to the wall [16]. The received power was measured from 10°to 170°(the received power at 0°and 180°are not able to measure due to the physical size of the antenna).…”

Section: A Measurements Setupmentioning

confidence: 99%

“…Comparisons between measurements and predictions made by a dual-lobe directive scattering (DS) model (as introduced in [16], [25]) with TX incident angle θ i = 10°, 30°, 60°, and 80°are shown in Fig. 2(b), 2(d), and 2(f).…”

Section: Scattering At Mmwave and Thzmentioning

confidence: 99%

“…At mmWave and THz frequencies, the wavelength λ becomes small, motivating the use of hybrid beamforming for "practical antenna packaging" [2], [15]. At sub-THz, λ is comparable to or smaller than the surface roughness of many objects, which suggests that scattering may not be neglected like it was when compared to reflection and diffraction at microwave frequencies (300 MHz to 3 GHz) [16].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Indoor Wireless Channel Properties at Millimeter Wave and Sub-Terahertz Frequencies

Xing¹,

Kanhere²,

Ju³

et al. 2019

2019 IEEE Global Communications Conference (GLOBECOM)

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108

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This paper provides indoor reflection, scattering, transmission, and large-scale path loss measurements and models, which describe the main propagation mechanisms at millimeter wave and Terahertz frequencies. Channel properties for common building materials (drywall and clear glass) are carefully studied at 28, 73, and 140 GHz using a wideband sliding correlation based channel sounder system with rotatable narrow-beam horn antennas. Reflection coefficient is shown to linearly increase as the incident angle increases, and lower reflection loss (e.g., stronger reflections) are observed as frequencies increase for a given incident angle. Although backscatter from drywall is present at 28, 73, and 140 GHz, smooth surfaces (like drywall) are shown to be modeled as a simple reflected surface, since the scattered power is 20 dB or more below the reflected power over the measured range of frequency and angles. Partition loss tends to increase with frequency, but the amount of loss is material dependent. Both clear glass and drywall are shown to induce a depolarizing effect, which becomes more prominent as frequency increases. Indoor propagation measurements and large-scale indoor path loss models at 140 GHz are provided, revealing similar path loss exponent and shadow fading as observed at 28 and 73 GHz. The measurements and models in this paper can be used for future wireless system design and other applications within buildings for frequencies above 100 GHz.

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Section: A Measurements Setupmentioning

confidence: 99%

Section: Scattering At Mmwave and Thzmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Indoor Wireless Channel Properties at Millimeter Wave and Sub-Terahertz Frequencies

Xing¹,

Kanhere²,

Ju³

et al. 2019

2019 IEEE Global Communications Conference (GLOBECOM)

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108

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“…There have been many works in recent times that have developed non-absorbing or non-scattering metasurface walls for reflecting electromagnetic waves [34], and an in particular programmable metasurfaces [35], [11].…”

Section: B Graphene-enabled Tunable Metamaterials Wallmentioning

confidence: 99%

Digital Twin for Metasurface Reflector Management in 6G Terahertz Communications

et al. 2020

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The performance demands from data-intensive applications, such as multimedia streaming, as well as the growing number of devices connecting to the Internet, will increase the need for higher capacity wireless communication links. The research community has recently explored regions of the spectrum, including the Terahertz band (0.1 THz to 10 THz), that are underutilised for communications. THz frequencies come with a plethora of special challenges, one of which is the very narrow effective beam, thereby requiring a Line of Sight (LoS) between sender and receiver. Researchers have explored the use of reflectors that can redirect beams around blockages. In this paper, we propose a THz signal guidance system where a Digital Twin is used to model, predict and control the signal propagation characteristics of an indoor space. Our approach finds the best THz signal path from the base station to the mobile target via the tunable metamaterial walls, avoiding obstacles as needed, using geometric (ray tracing), path loss and Terahertz Potential Field (THzPF) models. With this knowledge, the digital twin guides the selection of antenna strips at a base station and the reflectors along the signal path. A top-view camera, with advanced image processing, provides context updates (obstacle and mobile target locations) to the digital twin. The image processing system also senses factors like water vapour concentration, and the material composition and surface roughness of obstacles. Such factors affect propagation strength, and the digital twin modifies the beam paths to adapt. Simulation results have shown the efficiency of our control system to maintain a reliable signal connection while minimising the use of antenna and reflector strips. Our system is the first proposal that maximises THz signal-to-noise ratio (SNR) through such a dynamic and robust control system, which integrates image processing of a room with base station configuration.

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“…The transmitted ray was assumed to propagate in the same direction as the incident ray. A linear model was used to characterize the variation of reflection coefficient Γ with incident angle θ i , based on reflection measurements conducted in [17], [18] as follows:…”

Section: Nyuray -A 3-d Mmwave Ray Tracermentioning

confidence: 99%

Map-Assisted Millimeter Wave Localization for Accurate Position Location

Kanhere¹,

Ju²,

Xing³

et al. 2019

2019 IEEE Global Communications Conference (GLOBECOM)

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Accurate precise positioning at millimeter wave frequencies is possible due to the large available bandwidth that permits precise on-the-fly time of flight measurements using conventional air interface standards. In addition, narrow antenna beamwidths may be used to determine the angles of arrival and departure of the multipath components between the base station and mobile users. By combining accurate temporal and angular information of multipath components with a 3-D map of the environment (that may be built by each user or downloaded a-priori), robust localization is possible, even in non-line-of-sight environments. In this work, we develop an accurate 3-D ray tracer for an indoor office environment and demonstrate how the fusion of angle of departure and time of flight information in concert with a 3-D map of a typical large office environment provides a mean accuracy of 12.6 cm in line-of-sight and 16.3 cm in non-line-of-sight, over 100 receiver distances ranging from 1.5 m to 24.5 m using a single base station. We show how increasing the number of base stations improves the average non-line-of-sight position location accuracy to 5.5 cm at 21 locations with a maximum propagation distance of 24.5 m.

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Scattering Mechanisms and Modeling for Terahertz Wireless Communications

Cited by 98 publications

References 22 publications

Indoor Wireless Channel Properties at Millimeter Wave and Sub-Terahertz Frequencies

Indoor Wireless Channel Properties at Millimeter Wave and Sub-Terahertz Frequencies

Digital Twin for Metasurface Reflector Management in 6G Terahertz Communications

Map-Assisted Millimeter Wave Localization for Accurate Position Location

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