{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,5]],"date-time":"2026-03-05T07:53:51Z","timestamp":1772697231179,"version":"3.50.1"},"reference-count":64,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,3,5]],"date-time":"2026-03-05T00:00:00Z","timestamp":1772668800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Commun. Netw."],"abstract":"<jats:p>\n                    The Internet of Things (IoT) is increasingly used in agriculture, logistics, smart cities, environmental monitoring, and industrial automation. However, many remote, rural, maritime, and disaster-prone regions remain disconnected because deploying terrestrial infrastructure is prohibitively expensive or technically infeasible. Direct-to-Satellite IoT (DtS-IoT) addresses this gap by leveraging Low Power Wide Area Network (LPWAN) technologies, such as adapted LoRa and Narrowband IoT (NB-IoT), which both enable direct communication between IoT devices and Low Earth Orbit (LEO) satellites and provide the long-range, low-power operation required for such links. This tutorial paper provides a structured and accessible introduction to DtS-IoT. Building on recent literature, it covers seven major themes: (\n                    <jats:italic>i<\/jats:italic>\n                    ) system architectures, (\n                    <jats:italic>ii<\/jats:italic>\n                    ) constellation design, (\n                    <jats:italic>iii<\/jats:italic>\n                    ) LPWAN protocols, (\n                    <jats:italic>iv<\/jats:italic>\n                    ) key challenges, (\n                    <jats:italic>v<\/jats:italic>\n                    ) simulation tools, (\n                    <jats:italic>vi<\/jats:italic>\n                    ) experimental studies, and (\n                    <jats:italic>vii<\/jats:italic>\n                    ) future directions and open research issues. The goal is to guide the reader through the foundational concepts, design principles, and current technological landscape of DtS-IoT, offering a comprehensive set of references for further study.\n                  <\/jats:p>","DOI":"10.3389\/frcmn.2026.1750955","type":"journal-article","created":{"date-parts":[[2026,3,5]],"date-time":"2026-03-05T06:54:51Z","timestamp":1772693691000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Direct-to-satellite internet of things (DtS-IoT): a tutorial review on architectures, protocols, and future directions"],"prefix":"10.3389","volume":"7","author":[{"given":"Serdar","family":"Akar","sequence":"first","affiliation":[{"name":"NavRA and Computer Scientist","place":["Instanbul, T\u00fcrkiye"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alessandro","family":"Compagnoni","sequence":"additional","affiliation":[{"name":"Department of Electronic and Telecommunications, Politecnico di Torino","place":["Turin, Italy"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Juan A.","family":"Fraire","sequence":"additional","affiliation":[{"name":"Inria, INSA Lyon, CITI, UR3720","place":["Villeurbanne, France"]},{"name":"Facultad de Ciencias Exactas, Fisicas, y Naturales, CONICET - Universidad Nacional de C\u00f3rdoba","place":["C\u00f3rdoba, Argentina"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Roberto","family":"Garello","sequence":"additional","affiliation":[{"name":"Department of Electronic and Telecommunications, Politecnico di Torino","place":["Turin, Italy"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,3,5]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"2131","DOI":"10.1109\/LCOMM.2024.3434433","article-title":"Doppler shift distribution in satellite constellations","volume":"28","author":"Al-Hourani","year":"2024","journal-title":"IEEE Commun. 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