Radio Spectrum Occupancy Measurements Amid COVID-19 Telework and Telehealth

Published

October 14, 2022

Author(s)

Dan Kuester, Xifeng Lu, Dazhen Gu, Azizollah Kord, Jake Rezac, Katie Carson, Marla L. Dowell, Elizabeth Eyeson, Ari Feldman, Keith Forsyth, Vu Le, John Marts, Mike McNulty, Kyle Neubarth, Andre Rosete, Matthew Ryan, Maija Teraslina

Abstract

During the COVID-19 pandemic, NIST began a targeted campaign of measurements of averaged power and occupancy rate in the radio spectrum. The purpose was to sample real environments to offer timely insights into data infrastructure where it might be strained by stay-at-home and quarantine orders. The findings from this study could be applied to testing to support network resilience and receiver immunity in future stay-at-home disaster scenarios. Researchers who began working from home found themselves embedded in examples of the field sites that needed to be studied. Measurements began in 13 residential sites after a rapid engineering development effort, followed by spot measurements at a local hospital in the Denver metropolitan area. The study targeted radio frequency allocations that support key wireless data infrastructure. These included the cellular network bands below 1 GHz, and the unlicensed bands that support WLAN and WPAN traffic near 2.4 GHz and 5 GHz. The principal test locations were the home telework sites of NIST research staff, postdoctoral researchers, graduate and undergraduate students, and summer high school interns. Measurements continued where possible from late spring in 2020 until the autumn of 2021. This report details the study and its results, beginning from its conception and specification and continuing through its execution to a summary analysis of the resulting data, which is also publicly available. The key observations are as follows: - In uplink channels of cellular frequency bands, as well as unlicensed radio bands, sensors observed low rates of occupancy. Transmissions that did occur appeared as short bursts: in all cases the 90th percentile of the transmission duration was no greater than 4 ms. - In downlink channels of cellular frequency bands, occupancy rates were high, reflecting nearly continuous broadcasting. - A strong diurnal characteristic was observed, with average downlink power levels reduced by approximately 5 dB between 23:30 and 07:30 local time. These characteristics were broadly similar across all residential and hospital sites. The specific distributions of these paramaters can now be used to help design test cases to ensure the continued resilience of wireless infrastructure in residential or health care shelter-in-place scenarios. In particular, we conclude with recommendations about the burst timing parameters for emulating the observed traffic in electromagnetic compatibility testing. Through the development of the distributed sensor network, the team also produced new contributions to engineering and metrology for these problems. These included - techniques for tuning sensors when precision laboratory calibration is not available, - calibration methods for assembled software-defined radios, and - assessments of the performance of spectrum sensors in the field.

Citation

Technical Note (NIST TN) - 2240

Report Number

2240

NIST Pub Series

Technical Note (NIST TN)

Pub Type

NIST Pubs

Download Paper

https://doi.org/10.6028/NIST.TN.2240

Local Download

Keywords

spectrum sensing, spectrum monitoring, covid-19

Citation

Kuester, D. , Lu, X. , Gu, D. , Kord, A. , Rezac, J. , Carson, K. , Dowell, M. , Eyeson, E. , Feldman, A. , Forsyth, K. , Le, V. , Marts, J. , McNulty, M. , Neubarth, K. , Rosete, A. , Ryan, M. and Teraslina, M. (2022), Radio Spectrum Occupancy Measurements Amid COVID-19 Telework and Telehealth, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.TN.2240, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934697 (Accessed April 19, 2024)