Abstract—This letter provides a comparison of indoor radio
propagation measurements and corresponding channel statistics
at 28, 73, and 140 GHz, based on extensive measurements
from 2014-2020 in an indoor office environment. Side-by-side
comparisons of propagation characteristics (e.g., large-scale path
loss and multipath time dispersion) across a wide range of
frequencies from the low millimeter wave band of 28 GHz to
the sub-THz band of 140 GHz illustrate the key similarities
and differences in indoor wireless channels. The measurements
and models show remarkably similar path loss exponents over
frequencies in both line-of-sight (LOS) and non-LOS (NLOS)
scenarios, when using a one meter free space reference distance,
while the multipath time dispersion becomes smaller at higher
frequencies. The 3GPP indoor channel model overestimates the
large-scale path loss and has unrealistic large numbers of clusters
and multipath components per cluster compared to the measured
channel statistics in this letter.
Index Terms—mmWave, THz, channel models, multipath time
dispersion, 5G, 6G, large-scale path loss, 3GPP InH.
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Indoor Wireless Channel Properties at Millimeter Wave and Sub-Terahertz Frequencies
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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- NSF-PAR ID:
- 10205766
- Date Published:
- Journal Name:
- 2019 International Conference on Communications
- Page Range / eLocation ID:
- 1 to 6
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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