{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:57:32Z","timestamp":1760144252638,"version":"build-2065373602"},"reference-count":42,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2024,3,30]],"date-time":"2024-03-30T00:00:00Z","timestamp":1711756800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Low-Power Wide-Area Networks constitute a leading, emerging Internet-of-Things technology, with important applications in environmental and industrial monitoring and disaster prevention and management. In such sensor networks, external detectable events can trigger synchronized alarm report transmissions. In LoRaWANs, and more generally in networks with a random access-based medium access algorithm, this can lead to a cascade of frame collisions, temporarily resulting in degraded performance and diminished system operational capacity, despite LoRaWANs\u2019 physical layer interference and collision reduction techniques. In this paper, a novel scheduling algorithm is proposed that can increase system reliability in the case of such events. The new adaptive spatial scheduling algorithm is based on learning automata, as well as previous developments in scheduling over LoRaWANs, and it leverages network feedback information and traffic spatial correlation to increase network performance while maintaining high reliability. The proposed algorithm is investigated via an extensive simulation under a variety of network conditions and compared with a previously proposed scheduler for event-triggered traffic. The results show a decrease of up to 30% in average frame delay compared to the previous approach and an order of magnitude lower delay compared to the baseline algorithm. These findings highlight the importance of using spatial information in adaptive schemes for improving network performance, especially in location-sensitive applications.<\/jats:p>","DOI":"10.3390\/s24072222","type":"journal-article","created":{"date-parts":[[2024,3,31]],"date-time":"2024-03-31T13:32:56Z","timestamp":1711891976000},"page":"2222","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Adaptive Spatial Scheduling for Event Traffic in LoRaWAN Networks"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8211-2377","authenticated-orcid":false,"given":"Vassilis","family":"Asteriou","sequence":"first","affiliation":[{"name":"Department of Informatics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece"}]},{"given":"Konstantinos","family":"Kantelis","sequence":"additional","affiliation":[{"name":"Department of Informatics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece"}]},{"given":"Georgia A.","family":"Beletsioti","sequence":"additional","affiliation":[{"name":"Department of Informatics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece"}]},{"given":"Anastasios","family":"Valkanis","sequence":"additional","affiliation":[{"name":"Department of Informatics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5059-3145","authenticated-orcid":false,"given":"Petros","family":"Nicopolitidis","sequence":"additional","affiliation":[{"name":"Department of Informatics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece"}]},{"given":"Georgios","family":"Papadimitriou","sequence":"additional","affiliation":[{"name":"Department of Informatics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece"}]}],"member":"1968","published-online":{"date-parts":[[2024,3,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"77454","DOI":"10.1109\/ACCESS.2018.2883151","article-title":"Low Power Wide Area Networks: A Survey of Enabling Technologies, Applications and Interoperability Needs","volume":"6","author":"Qadir","year":"2018","journal-title":"IEEE Access"},{"key":"ref_2","unstructured":"Laner, M., Svoboda, P., Nikaein, N., and Rupp, M. (2013, January 27\u201330). Traffic Models for Machine Type Communications. Proceedings of the Tenth International Symposium on Wireless Communication Systems (ISWCS 2013), Ilmenau, Germany."},{"key":"ref_3","unstructured":"Technical Specification Group Radio Access Network (2011). Study on RAN Improvements for Machine-Type Communications, 3rd Generation Partnership Project. Technical Report 37.868 V11.0.0."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Gupta, V., Devar, S.K., Kumar, N.H., and Bagadi, K.P. (2017, January 4\u20138). Modelling of IoT Traffic and Its Impact on LoRaWAN. Proceedings of the GLOBECOM 2017\u20142017 IEEE Global Communications Conference, Singapore.","DOI":"10.1109\/GLOCOM.2017.8254512"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"93651","DOI":"10.1109\/ACCESS.2021.3093421","article-title":"Autonomous Decentralized Traffic Control Using Q-Learning in LPWAN","volume":"9","author":"Kaburaki","year":"2021","journal-title":"IEEE Access"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Tsakmakis, A., Valkanis, A., Beletsioti, G., Kantelis, K., Nicopolitidis, P., and Papadimitriou, G. (2022). An Adaptive LoRaWAN MAC Protocol for Event Detection Applications. Sensors, 22.","DOI":"10.3390\/s22093538"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"97465","DOI":"10.1109\/ACCESS.2022.3204654","article-title":"LoRaWAN-Based Adaptive MACs for Event Response Applications","volume":"10","author":"Asteriou","year":"2022","journal-title":"IEEE Access"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Zorbas, D., Abdelfadeel, K.Q., Cionca, V., Pesch, D., and O\u2019Flynn, B. (2019, January 15\u201318). Offline Scheduling Algorithms for Time-Slotted LoRa-based Bulk Data Transmission. Proceedings of the 2019 IEEE 5th World Forum on Internet of Things (WF-IoT), Limerick, Ireland.","DOI":"10.1109\/WF-IoT.2019.8767277"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"669","DOI":"10.1109\/JIOT.2019.2949918","article-title":"FREE \u2014Fine-Grained Scheduling for Reliable and Energy-Efficient Data Collection in LoRaWAN","volume":"7","author":"Abdelfadeel","year":"2020","journal-title":"IEEE Internet Things J."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"3097","DOI":"10.1109\/JIOT.2018.2878942","article-title":"Low Overhead Scheduling of LoRa Transmissions for Improved Scalability","volume":"6","author":"Haxhibeqiri","year":"2019","journal-title":"IEEE Internet Things J."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"12919","DOI":"10.1109\/JIOT.2021.3064430","article-title":"LoRaWAN Scheduling: From Concept to Implementation","volume":"8","author":"Haxhibeqiri","year":"2021","journal-title":"IEEE Internet Things J."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Xu, Z., Luo, J., Yin, Z., He, T., and Dong, F. (2020, January 6\u20139). S-MAC: Achieving High Scalability via Adaptive Scheduling in LPWAN. Proceedings of the IEEE INFOCOM 2020\u2014IEEE Conference on Computer Communications, Toronto, ON, Canada.","DOI":"10.1109\/INFOCOM41043.2020.9155474"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Chinchilla-Romero, N., Navarro-Ortiz, J., Mu\u00f1oz, P., and Ameigeiras, P. (2021). Collision Avoidance Resource Allocation for LoRaWAN. Sensors, 21.","DOI":"10.3390\/s21041218"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Kaburaki, A., Adachi, K., Takyu, O., Ohta, M., and Fujii, T. (IEEE Trans. Wirel. Commun., 2023). Adaptive Resource Allocation Utilizing Periodic Traffic and Clock Drift in LPWAN, IEEE Trans. Wirel. Commun., Early Access.","DOI":"10.1109\/TWC.2023.3311679"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2815","DOI":"10.1109\/OJCOMS.2023.3321875","article-title":"A New Schedule-Based Scheme for Uplink Communications in LoRaWAN","volume":"4","author":"Baccour","year":"2023","journal-title":"IEEE Open J. Commun. Soc."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"11368","DOI":"10.1109\/JIOT.2021.3051347","article-title":"Analysis and Implementation for Traffic-Aware Channel Assignment and Contention Scheme in LoRa-Based IoT Networks","volume":"8","author":"Shen","year":"2021","journal-title":"IEEE Internet Things J."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Asteriou, V., Papadimitriou, G., and Nicopolitidis, P. (2021, January 24\u201328). Adaptive MAC Protocols for IoT Edge Computing Architectures with Event-Triggered Traffic. Proceedings of the 2021 IEEE International Black Sea Conference on Communications and Networking (BlackSeaCom), Bucharest, Romania.","DOI":"10.1109\/BlackSeaCom52164.2021.9527755"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Piyare, R., Murphy, A.L., Magno, M., and Benini, L. (2018). On-Demand LoRa: Asynchronous TDMA for Energy Efficient and Low Latency Communication in IoT. Sensors, 18.","DOI":"10.3390\/s18113718"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Fr\u00f8ytlog, A., Haglund, M.A., Cenkeramaddi, L.R., and Beferull-Lozano, B. (2019, January 16\u201319). Design and implementation of a long-range low-power wake-up radio and customized DC-MAC protocol for LoRaWAN. Proceedings of the 2019 IEEE International Conference on Advanced Networks and Telecommunications Systems (ANTS), Goa, India.","DOI":"10.1109\/ANTS47819.2019.9118165"},{"key":"ref_20","unstructured":"Slats, L. (2024, February 28). A Brief History of LoRa: Three Inventors Share Their Story, at Inside Out: Semtech\u2019s Corporate Blog. Available online: https:\/\/blog.semtech.com\/a-brief-history-of-lora-three-inventors-share-their-personal-story-at-the-things-conference."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"322","DOI":"10.3390\/telecom3020018","article-title":"LoRaWAN Communication Protocols: A Comprehensive Survey under an Energy Efficiency Perspective","volume":"3","author":"Banti","year":"2022","journal-title":"Telecom"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1818","DOI":"10.1109\/LSP.2017.2762960","article-title":"Frequency Shift Chirp Modulation: The LoRa Modulation","volume":"24","author":"Vangelista","year":"2017","journal-title":"IEEE Signal Process. Lett."},{"key":"ref_23","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_24","unstructured":"Technical Specification Group GSM\/EDGE Radio Access Network (2015). Cellular System Support for Ultra-Low Complexity and Low Throughput Internet of Things (CIoT), 3rd Generation Partnership Project. Technical Report 45.820 V13.1.0."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1109\/JIOT.2015.2496418","article-title":"Reliable and Efficient Access for Alarm-Initiated and Regular M2M Traffic in IEEE 802.11ah Systems","volume":"3","author":"Popovski","year":"2016","journal-title":"IEEE Internet Things J."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2378","DOI":"10.1073\/pnas.1417043112","article-title":"Warning signals for eruptive events in spreading fires","volume":"112","author":"Fox","year":"2015","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_27","first-page":"1","article-title":"Efficient Forest Fire Detection System Based on Data Fusion Applied in Wireless Sensor Networks","volume":"12","author":"Jilbab","year":"2020","journal-title":"Int. J. Electr. Eng. Inform."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Mousavi, A., Duckham, M., Kotagiri, R., and Rajabifard, A. (2013, January 16\u201319). Spatio-temporal event detection using probabilistic graphical models (PGMs). Proceedings of the 2013 IEEE Symposium on Computational Intelligence and Data Mining (CIDM), Singapore.","DOI":"10.1109\/CIDM.2013.6597221"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Bridson, R. (2007, January 5\u20139). Fast Poisson disk sampling in arbitrary dimensions. Proceedings of the ACM SIGGRAPH 2007 Sketches. Association for Computing Machinery (SIGGRAPH\u201907), San Diego, CA, USA.","DOI":"10.1145\/1278780.1278807"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1186\/s13638-019-1502-5","article-title":"Impact of EU duty cycle and transmission power limitations for sub-GHz LPWAN SRDs: An overview and future challenges","volume":"2019","author":"Saelens","year":"2019","journal-title":"J. Wirel. Commun. Netw."},{"key":"ref_31","unstructured":"LoRa Alliance (2020). LoRaWAN\u00ae L2 1.0.4 Specification, LoRa Alliance. Technical Specification TS001-1.0.4."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1016\/0021-9991(78)90081-5","article-title":"Note rapid calculation of coordinates from distance matrices","volume":"26","author":"Crippen","year":"1978","journal-title":"J. Comput. Phys."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1109\/MSP.2015.2398954","article-title":"Euclidean Distance Matrices: Essential theory, algorithms, and applications","volume":"32","author":"Dokmanic","year":"2015","journal-title":"IEEE Signal Process. Mag."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"781","DOI":"10.1109\/TSMCB.2002.1049612","article-title":"On the use of learning automata in the control of broadcast networks: A methodology","volume":"32","author":"Papadimitriou","year":"2002","journal-title":"IEEE Trans. Syst. Man, Cybern. Part B (Cybern.)"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"101978","DOI":"10.1109\/ACCESS.2020.2996279","article-title":"A Learning-Automata-Based Congestion-Aware Scheme for Energy-Efficient Elastic Optical Networks","volume":"8","author":"Beletsioti","year":"2020","journal-title":"IEEE Access"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2186","DOI":"10.1109\/JIOT.2017.2768498","article-title":"Scalability Analysis of Large-Scale LoRaWAN Networks in NS-3","volume":"4","author":"Haxhibeqiri","year":"2017","journal-title":"IEEE Internet Things J."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"800","DOI":"10.1109\/LCOMM.2018.2797274","article-title":"Spreading Factor Allocation for Massive Connectivity in LoRa Systems","volume":"22","author":"Lim","year":"2018","journal-title":"IEEE Commun. Lett."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1239\/aap\/1113402397","article-title":"Connectivity of Random k-Nearest-Neighbour Graphs","volume":"37","author":"Balister","year":"2005","journal-title":"Adv. Appl. Probab."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"114","DOI":"10.13164\/re.2016.0114","article-title":"Congestion-Aware Routing and Fuzzy-based Rate Controller for Wireless Sensor Networks","volume":"25","author":"Hatamian","year":"2016","journal-title":"Radioengineering"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"360","DOI":"10.1080\/00207217.2021.2025451","article-title":"Cluster based routing method using mobile sinks in wireless sensor network","volume":"110","author":"Dehkordi","year":"2023","journal-title":"Int. J. Electron."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Sundas, A., Badotra, S., Bharany, S., Almogren, A., Tag-ElDin, E.M., and Rehman, A.U. (2022). HealthGuard: An Intelligent Healthcare System Security Framework Based on Machine Learning. Sustainability, 14.","DOI":"10.3390\/su141911934"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Adeniyi, E.A., Falola, P.B., Maashi, M.S., Aljebreen, M., and Bharany, S. (2022). Secure Sensitive Data Sharing Using RSA and ElGamal Cryptographic Algorithms with Hash Functions. Information, 13.","DOI":"10.3390\/info13100442"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/7\/2222\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:21:22Z","timestamp":1760106082000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/7\/2222"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,3,30]]},"references-count":42,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2024,4]]}},"alternative-id":["s24072222"],"URL":"https:\/\/doi.org\/10.3390\/s24072222","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2024,3,30]]}}}