Sub-Terahertz (THz) frequencies between 100 GHz
and 300 GHz are being considered as a key enabler for the sixthgeneration
(6G) wireless communications due to the vast amounts
of unused spectrum. The 3rd Generation Partnership Project
(3GPP) included the indoor industrial environments as a scenario
of interest since Release 15. This paper presents recent sub-
THz channel measurements using directional horn antennas of
27 dBi gain at 142 GHz in a factory building, which hosts equipment
manufacturing startups. Directional measurements with copolarized
and cross-polarized antenna configurations were conducted
over distances from 6 to 40 meters. Omnidirectional and
directional path loss with two antenna polarization configurations
produce the gross cross-polarization discrimination (XPD) with
a mean of 27.7 dB, which suggests that dual-polarized antenna
arrays can provide good multiplexing gain for sub-THz wireless
systems. The measured power delay profile and power angular
spectrum show the maximum root mean square (RMS) delay
spread of 66.0 nanoseconds and the maximum RMS angular
spread of 103.7 degrees using a 30 dB threshold, indicating the
factory scenario is a rich-scattering environment due to a massive
number of metal structures and objects. This work will facilitate
emerging sub-THz applications such as super-resolution sensing
and positioning for future smart factories.
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Experimental Evaluation of Antenna Polarization and Elevation Effects on Drone Communications
In the next wave of swarm-based applications, unmanned aerial vehicles (UAVs) need to communicate with peer drones in any direction of a three-dimensional (3D) space. On a given drone and across drones, various antenna positions and orientations are possible. We know that, in free space, high levels of signal loss are expected if the transmitting and receiving antennas are cross polarized. However, increasing the reflective and scattering objects in the channel between a transmitter and receiver can cause the received polarization to become completely independent from the transmitted polarization, making the cross-polarization of antennas insignificant. Usually, these effects are studied in the context of cellular and terrestrial networks and have not been analyzed when those objects are the actual bodies of the communicating drones that can take different relative directions or move at various elevations. In this work, we show that the body of the drone can affect the received power across various antenna orientations and positions and act as a local scatterer that increases channel depolarization, reducing the cross-polarization discrimination (XPD). To investigate these effects, we perform experimentation that is staged in terms of complexity from a controlled environment of an anechoic chamber with and without drone bodies to in-field environments where drone-mounted antennas are in-flight with various orientations and relative positions with the following outcomes: (i.) drone relative direction can significantly impact the XPD values, (ii.) elevation angle is a critical factor in 3D link performance, (iii.) antenna spacing requirements are altered for co-located cross-polarized antennas, and (iv.) cross-polarized antenna setups more than double spectral efficiency. Our results can serve as a guide for accurately simulating and modeling UAV networks and drone swarms.
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- Award ID(s):
- 1823304
- NSF-PAR ID:
- 10196177
- Date Published:
- Journal Name:
- Proceedings of the 22nd ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (ACM MSWiM)
- Page Range / eLocation ID:
- 211 to 220
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1145/3345768.3355916
