{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,17]],"date-time":"2026-06-17T14:19:48Z","timestamp":1781705988860,"version":"3.54.5"},"reference-count":30,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2025,11,13]],"date-time":"2025-11-13T00:00:00Z","timestamp":1762992000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Missouri S&T Experimental Mine"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Information"],"abstract":"<jats:p>Underground mine emergencies destroy communication infrastructure when situational awareness is most critical. Current systems rely on centralized network infrastructure, which fails during emergencies when miners are trapped and require rescue coordination. This paper proposes an energy-harvesting LoRa mesh network that addresses self-powered operation, interference management, and adaptive physical layer optimization under severe underground propagation conditions. A dual-antenna architecture separates RF energy harvesting (860 MHz) from LoRa communication (915 MHz), enabling continuous operation with supercapacitor storage. The core contribution is a decentralized scheduler that derives optimal timing offsets by modeling concurrent transmissions as a Poisson collision process, exploiting LoRa\u2019s capture effect while maintaining network coherence. A SINR-aware physical layer adapts spreading factor, bandwidth, and coding rate with hysteresis, controls recomputing timing parameters after each change. Experimental validation in Missouri S&amp;T\u2019s operational mine demonstrates far-field wireless power transfer (WPT) reaching 35 m. Simulations across 2000 independent trials show a 2.2\u00d7 throughput improvement over ALOHA (49% vs. 22% delivery ratio at 10 nodes\/hop), 64% collision reduction, and 67% energy efficiency gains, demonstrating resilient emergency communications for underground environments.<\/jats:p>","DOI":"10.3390\/info16110984","type":"journal-article","created":{"date-parts":[[2025,11,14]],"date-time":"2025-11-14T17:33:21Z","timestamp":1763141601000},"page":"984","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Energy-Harvesting Concurrent LoRa Mesh with Timing Offsets for Underground Mine Emergency Communications"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-6049-2479","authenticated-orcid":false,"given":"Hilary Kelechi","family":"Anabi","sequence":"first","affiliation":[{"name":"Department of Mining and Explosives Engineering, Missouri University of Science and Technology, Rolla, MS 654091, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8300-6824","authenticated-orcid":false,"given":"Samuel","family":"Frimpong","sequence":"additional","affiliation":[{"name":"Department of Mining and Explosives Engineering, Missouri University of Science and Technology, Rolla, MS 654091, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sanjay","family":"Madria","sequence":"additional","affiliation":[{"name":"Department of Computer Science, Missouri University of Science and Technology, Rolla, MS 65409, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,11,13]]},"reference":[{"key":"ref_1","first-page":"2009","article-title":"Two Years After the MINER Act: How safe is Mining Today","volume":"21","author":"Kohler","year":"2008","journal-title":"Coal Mine Saf."},{"key":"ref_2","unstructured":"MHSA (2024, 5 August 2024). Fatality Reports, Available online: https:\/\/www.msha.gov\/data-and-reports\/fatality-reports\/search."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"946","DOI":"10.1016\/j.psep.2021.03.049","article-title":"Towards an emergency preparedness for self-rescue from underground coal mines","volume":"149","author":"Onifade","year":"2021","journal-title":"Process Saf. Environ. Prot."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1016\/j.shaw.2021.10.003","article-title":"Internet of things\u2013based command center to improve emergency response in underground mines","volume":"13","author":"Jha","year":"2022","journal-title":"Saf. Health Work"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"22836","DOI":"10.1109\/JIOT.2022.3185619","article-title":"A hierarchy-based energy-efficient routing protocol for LoRa-mesh network","volume":"9","author":"Hong","year":"2022","journal-title":"IEEE Internet Things J."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2347","DOI":"10.1109\/COMST.2015.2444095","article-title":"Internet of things: A survey on enabling technologies, protocols, and applications","volume":"17","author":"Guizani","year":"2015","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1145\/3638241","article-title":"Multi-hop and mesh for LoRa networks: Recent advancements, issues, and recommended applications","volume":"56","author":"Wong","year":"2024","journal-title":"ACM Comput. Surv."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Tran, H.P., Jung, W.-S., Yoo, D.-S., and Oh, H. (2022). Design and implementation of a multi-hop real-time LoRa protocol for dynamic LoRa networks. Sensors, 22.","DOI":"10.3390\/s22093518"},{"key":"ref_9","first-page":"361","article-title":"LoRa for the Internet of Things","volume":"16","author":"Bor","year":"2016","journal-title":"Ewsn"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Leenders, G., Callebaut, G., Ottoy, G., Van der Perre, L., and De Strycker, L. (2023). An Energy-Efficient LoRa Multi-Hop Protocol through Preamble Sampling for Remote Sensing. Sensors, 23.","DOI":"10.3390\/s23114994"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"21430","DOI":"10.1109\/ACCESS.2017.2755858","article-title":"Multi-hop LoRa networks enabled by concurrent transmission","volume":"5","author":"Liao","year":"2017","journal-title":"IEEE Access"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1109\/MTTW51045.2020.9245073","article-title":"Experimental Analysis of LoRa Signals Employment for RF Energy Harvesting","volume":"Volume 1","author":"Eidaks","year":"2020","journal-title":"Proceedings of the 2020 IEEE Microwave Theory and Techniques in Wireless Communications (MTTW)"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2700","DOI":"10.1109\/JIOT.2018.2813162","article-title":"Multiband ambient RF energy harvesting circuit design for enabling batteryless sensors and IoT","volume":"5","author":"Muncuk","year":"2018","journal-title":"IEEE Internet Things J."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Polonelli, T., Brunelli, D., Marzocchi, A., and Benini, L. (2019). Slotted aloha on lorawan-design, analysis, and deployment. Sensors, 19.","DOI":"10.3390\/s19040838"},{"key":"ref_15","first-page":"70","article-title":"Improving lorawan performance using reservation aloha","volume":"12","author":"Ibrahim","year":"2020","journal-title":"J. Inf. Technol. Manag."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Kufakunesu, R., Hancke, G.P., and Abu-Mahfouz, A.M. (2020). A survey on adaptive data rate optimization in lorawan: Recent solutions and major challenges. Sensors, 20.","DOI":"10.3390\/s20185044"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Serati, R., Teymuri, B., Anagnostopoulos, N.A., and Rasti, M. (2022, January 10\u201312). ADR-lite: A low-complexity adaptive data rate scheme for the LoRa network. Proceedings of the 2022 18th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), Thessaloniki, Greece.","DOI":"10.1109\/WiMob55322.2022.9941614"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"15376","DOI":"10.1109\/JIOT.2023.3263630","article-title":"LoRaHop: Multihop support for LoRaWAN uplink and downlink messaging","volume":"10","author":"Tian","year":"2023","journal-title":"IEEE Internet Things J."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"6893","DOI":"10.3390\/s20236893","article-title":"JMAC protocol: A cross-layer multi-hop protocol for LoRa","volume":"20","author":"Escobar","year":"2020","journal-title":"Sensors"},{"key":"ref_20","unstructured":"P. P21XXCSR-EVB. P21XXPowerharvester\u00ae Chipset Reference Design Evaluation Board. Available online: https:\/\/www.powercastco.com\/wp-content\/uploads\/2021\/06\/P21XXCSR-EVB-Datasheet-v2.1-1.pdf."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1109\/JPROC.2021.3127930","article-title":"Far-field wireless power harvesting: Nonlinear modeling, rectenna design, and emerging applications","volume":"110","author":"Gu","year":"2021","journal-title":"Proc. IEEE"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1524","DOI":"10.1109\/SURV.2013.031413.00130","article-title":"A Survey of Wireless Communications and Propagation Modeling in Underground Mines","volume":"15","author":"Forooshani","year":"2013","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_23","first-page":"341","article-title":"Radio frequency energy harvesting and management for wireless sensor networks","volume":"13","author":"Zungeru","year":"2012","journal-title":"Green Mob. Devices Netw. Energy Optim. Scav. Tech."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"104","DOI":"10.1109\/MCOM.2014.6957150","article-title":"Simultaneous wireless information and power transfer in modern communication systems","volume":"52","author":"Krikidis","year":"2014","journal-title":"IEEE Commun. Mag."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"264","DOI":"10.1109\/COMST.2017.2783901","article-title":"Simultaneous wireless information and power transfer (SWIPT): Recent advances and future challenges","volume":"20","author":"Perera","year":"2017","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"540","DOI":"10.1109\/TAP.2007.913144","article-title":"Radio Wave Characterization and Modeling in Underground Mine Tunnels","volume":"56","author":"Boutin","year":"2008","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"796","DOI":"10.1109\/LCOMM.2018.2797057","article-title":"Impact of LoRa imperfect orthogonality: Analysis of link-level performance","volume":"22","author":"Croce","year":"2018","journal-title":"IEEE Commun. Lett."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"110194","DOI":"10.1016\/j.comnet.2024.110194","article-title":"SDR-LoRa, an open-source, full-fledged implementation of LoRa on Software-Defined-Radios: Design and potential exploitation","volume":"241","author":"Busacca","year":"2024","journal-title":"Comput. Netw."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"3756","DOI":"10.1109\/JIOT.2021.3101002","article-title":"A low-complexity LoRa synchronization algorithm robust to sampling time offsets","volume":"9","author":"Xhonneux","year":"2021","journal-title":"IEEE Internet Things J."},{"key":"ref_30","unstructured":"Horowitz, P., Hill, W., and Robinson, I. (1989). The Art of Electronics, Cambridge University Press."}],"container-title":["Information"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2078-2489\/16\/11\/984\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,11,14]],"date-time":"2025-11-14T17:36:13Z","timestamp":1763141773000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2078-2489\/16\/11\/984"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,11,13]]},"references-count":30,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2025,11]]}},"alternative-id":["info16110984"],"URL":"https:\/\/doi.org\/10.3390\/info16110984","relation":{},"ISSN":["2078-2489"],"issn-type":[{"value":"2078-2489","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,11,13]]}}}