Abstract—Sub-Terahertz frequencies (frequencies above 100
GHz) have the potential to satisfy the unprecedented demand on
data rate on the order of hundreds of Gbps for sixth-generation
(6G) wireless communications and beyond. Accurate beam tracking
and rapid beam selection are increasingly important since
antenna arrays with more elements generate narrower beams
to compensate for additional path loss within the first meter of
propagation distance at sub-THz frequencies. Realistic channel
models for above 100 GHz are needed, and should include spatial
consistency to model the spatial and temporal channel evolution
along the user trajectory. This paper introduces recent outdoor
urban microcell (UMi) propagation measurements at 142 GHz
along a 39 m 12 m rectangular route (102 m long), where
each consecutive and adjacent receiver location is 3 m apart
from each other. The measured power delay profiles and angular
power spectrum at each receiver location are used to study spatial
autocorrelation properties of various channel parameters such as
shadow fading, delay spread, and angular spread along the track.
Compared to the correlation distances reported in the 3GPP TR
38.901 for frequencies below 100 GHz, the measured correlation
distance of shadow fading at 142 GHz (3.8 m) is much shorter
than the 10-13 m as specified in 3GPP; the measured correlation
distances of delay spread and angular spread at 142 GHz (both 12
m) are comparable to the 7-10 m as specified in 3GPP. This result
may guide the development of a statistical spatially consistent
channel model for frequencies above 100 GHz in the UMi street
canyon environment.
Index Terms—Terahertz; Spatial Consistency; Channel Measurement;
Channel Modeling; 140 GHz; 142 GHz; 5G; 6G
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PropagationMeasurementsandPathLossModelsfor sub-THz inUrbanMicrocells
Terahertz frequency bands will likely be used for the next-generation wireless communication systems to provide data rates of hundreds of Gbps or even Tbps because of the wide swaths of unused and unexplored spectrum. This paper presents two outdoor wideband measurement campaigns in downtown Brooklyn (urban microcell environment) in the sub-THz band of 140 GHz with TX-RX separation distance up to 100 m: i) terrestrial urban microcell measurement campaign, and ii) rooftop surrogate satellite and backhaul measurement campaign. Outdoor omnidirectional and directional path loss models for both line-of-sight and non-line-of-sight scenarios, as well as foliage loss (signal attenuation through foliage), are provided at 140 GHz for urban microcell environments. These measurements and models provide an understanding of both the outdoor terrestrial (e.g., 6G cellular and backhaul) and non-terrestrial (e.g., satellite and unmanned aerial vehicle communications) wireless channels, and prove the feasibility of using THz frequency bands for outdoor fixed and mobile cellular communications. This paper can be used for future outdoor wireless system design at frequencies above 100 GHz.
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- NSF-PAR ID:
- 10309452
- Date Published:
- Journal Name:
- IEEE International Conference on Communications
- ISSN:
- 1550-3607
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract—Comparisons of outdoor Urban Microcell (UMi) large-scale path loss models, root mean square (RMS) delay spreads (DS), angular spreads (AS), and the number of spatial beams for extensive measurements performed at 28, 38, 73, and 142 GHz are presented in this letter. Measurement campaigns were conducted from 2011-2020 in downtown Austin, Texas, Manhattan (New York City), and Brooklyn, New York with communication ranges up to 930 m. Key similarities and differences in outdoor wireless channels are observed when comparing the channel statistics across a wide range of frequencies from millimeter-wave to sub-THz bands. Path loss exponents (PLEs) are remarkably similar over all measured frequencies, when referenced to the first meter free space path loss, and the RMS DS and AS decrease as frequency increases. The similar PLEs from millimeter-wave to THz frequencies imply that spacing between cellular base stations will not have to change as carrier frequencies increase towards THz, since wider bandwidth channels at sub-THz or THz carrier frequencies will cover similar distances because antenna gains increase quadratically with increasing frequency when the physical antenna area remain constant. Index Terms—5G; mmWave; 6G; THz; outdoor channel models; UMi; RMS delay and angular spread.more » « less
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Abstract—Millimeter-wave (mmWave) and Terahertz (THz) will be used in the sixth-generation (6G) wireless systems, especially for indoor scenarios. This paper presents an indoor three-dimensional (3-D) statistical channel model for mmWave and sub-THz frequencies, which is developed from extensive channel propagation measurements conducted in an office building at 28 GHz and 140 GHz in 2014 and 2019. Over 15,000 power delay profiles (PDPs) were recorded to study channel statistics such as the number of time clusters, cluster delays, and cluster powers. All the parameters required in the channel generation procedure are derived from empirical measurement data for 28 GHz and 140 GHz line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios. The channel model is validated by showing that the simulated root mean square (RMS) delay spread and RMS angular spread yield good agreements with measured values. An indoor channel simulation software is built upon the popular NYUSIM outdoor channel simulator, which can generate realistic channel impulse response, PDP, and power angular spectrum. Index Terms—Millimeter-Wave; Terahertz; Indoor Office; Channel Measurement; Channel Modeling; Channel Simulation; 5G; 6Gmore » « less
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