{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T16:39:40Z","timestamp":1782405580577,"version":"3.54.5"},"reference-count":39,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2021,6,10]],"date-time":"2021-06-10T00:00:00Z","timestamp":1623283200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Broadcasting and Telecommunications Research and Development Fund for Public Interest","award":["Setting Up a 5G Test Center in Chulalongkorn University (Development of Data Collection and Transfer for Air Quality Monitoring in Hospitals)"],"award-info":[{"award-number":["Setting Up a 5G Test Center in Chulalongkorn University (Development of Data Collection and Transfer for Air Quality Monitoring in Hospitals)"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>It is well-known that the analog FM radio channels in suburban areas are underutilized. Before reallocating the unused channels for other applications, a regulator must analyze the spectrum occupancy. Many researchers proposed the spectrum occupancy models to find vacant spectrum. However, the existing models do not analyze each channel individually. This paper proposes an approach consisting (i) a spectrum measurement strategy, (ii) an appropriate decision threshold, and (iii) criteria for channel classification, to find the unused channels. The measurement strategy monitors each channel\u2019s activity by capturing the power levels of the passband and the guardband separately. The decision threshold is selected depending on the monitored channel\u2019s activity. The criteria classifies the channels based on the passband\u2019s and guardband\u2019s duty cycles. The results show that the proposed channel classification can identify 42 unused channels. If the power levels of wholebands (existing model) were analyzed instead of passband\u2019s and guardband\u2019s duty cycles, only 24 unoccupied channels were found. Furthermore, we propose the interference criteria, based on relative duty cycles across channels, to classify the abnormally used channels into interference sources and interference sinks, which have 16 and 15 channels, respectively. This information helps the dynamic spectrum sharing avoid or mitigate the interferences.<\/jats:p>","DOI":"10.3390\/s21124015","type":"journal-article","created":{"date-parts":[[2021,6,10]],"date-time":"2021-06-10T21:34:38Z","timestamp":1623360878000},"page":"4015","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Spectrum Occupancy Model Based on Empirical Data for FM Radio Broadcasting in Suburban Environments"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6664-9641","authenticated-orcid":false,"given":"Ajalawit","family":"Chantaveerod","sequence":"first","affiliation":[{"name":"Center of Excellence in Sustainable Disaster Management, Department of Electrical Engineering, School of Engineering and Technology, Walailak University, Nakhon Si Thammarat 80161, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7383-0361","authenticated-orcid":false,"given":"Kampol","family":"Woradit","sequence":"additional","affiliation":[{"name":"OASYS Research Group, Department of Computer Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Charernkiat","family":"Pochaiya","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, School of Engineering and Technology, Walailak University, Nakhon Si Thammarat 80161, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,6,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Zulfiqar, M.D., Ismail, K., Hassan, N.U., Hussain, S., and Zhang, M. 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