{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,4]],"date-time":"2025-10-04T00:21:42Z","timestamp":1759537302297,"version":"build-2065373602"},"reference-count":18,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2025,10,1]],"date-time":"2025-10-01T00:00:00Z","timestamp":1759276800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"crossref","award":["62405371"],"award-info":[{"award-number":["62405371"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Future Internet"],"abstract":"<jats:p>Low-Earth-Orbit Satellite Internet (LEO SI), with its capability for seamless global coverage, is a key solution for connecting IoT devices in areas beyond terrestrial network reach, playing a vital role in building a future ubiquitous IoT system. Inspired by the IEEE 802.15.4 Improved Adaptive Backoff Algorithm (I-ABA), this paper proposes an Attack-Aware Adaptive Backoff Indicator (AA-BI) mechanism to enhance the security and robustness of the two-step random access process in LEO SI. The mechanism constructs a composite threat intensity indicator that incorporates collision probability, Denial-of-Service (DoS) attack strength, and replay attack intensity. This quantified threat level is smoothly mapped to a dynamic backoff window to achieve adaptive backoff adjustment. Simulation results demonstrate that, with 200 pieces of user equipment (UE), the AA-BI mechanism significantly improves the access success rate (ASR) and jamming resistance rate (JRR) under various attack scenarios compared to the I-ABA and Binary Exponential Backoff (BEB) algorithms. Notably, under high-attack conditions, AA-BI improves ASR by up to 25.1% and 56.6% over I-ABA and BEB, respectively. Moreover, under high-load conditions with 800 users, AA-BI still maintains superior performance, achieving an ASR of 0.42 and a JRR of 0.68, thereby effectively ensuring the access performance and reliability of satellite Internet in malicious environments.<\/jats:p>","DOI":"10.3390\/fi17100454","type":"journal-article","created":{"date-parts":[[2025,10,1]],"date-time":"2025-10-01T09:37:21Z","timestamp":1759311441000},"page":"454","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Enhancing Two-Step Random Access in LEO Satellite Internet an Attack-Aware Adaptive Backoff Indicator (AA-BI)"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-8913-9104","authenticated-orcid":false,"given":"Jiajie","family":"Dong","sequence":"first","affiliation":[{"name":"Anhui Province Key Laboratory of Electronic Restriction, Hefei 230037, China"},{"name":"College of Electronic Engineering, National University of Defense Technology, Hefei 230037, China"}]},{"given":"Yong","family":"Wang","sequence":"additional","affiliation":[{"name":"Anhui Province Key Laboratory of Electronic Restriction, Hefei 230037, China"},{"name":"College of Electronic Engineering, National University of Defense Technology, Hefei 230037, China"}]},{"given":"Qingsong","family":"Zhao","sequence":"additional","affiliation":[{"name":"Anhui Province Key Laboratory of Electronic Restriction, Hefei 230037, China"},{"name":"College of Electronic Engineering, National University of Defense Technology, Hefei 230037, China"}]},{"given":"Ruiqian","family":"Ma","sequence":"additional","affiliation":[{"name":"Anhui Province Key Laboratory of Electronic Restriction, Hefei 230037, China"},{"name":"College of Electronic Engineering, National University of Defense Technology, Hefei 230037, China"}]},{"given":"Jiaxiong","family":"Yang","sequence":"additional","affiliation":[{"name":"Anhui Province Key Laboratory of Electronic Restriction, Hefei 230037, China"},{"name":"College of Electronic Engineering, National University of Defense Technology, Hefei 230037, China"}]}],"member":"1968","published-online":{"date-parts":[[2025,10,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Zhou, Y., Chen, H., and Dou, Z. (2024). MOLM: Alleviating Congestion through Multi-Objective Simulated Annealing-Based Load Balancing Routing in LEO Satellite Networks. Future Internet, 16.","DOI":"10.3390\/fi16040109"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"3717","DOI":"10.1109\/TAES.2022.3155711","article-title":"Refracting RIS-Aided Hybrid Satellite-Terrestrial Relay Networks: Joint Beamforming Design and Optimization","volume":"58","author":"Lin","year":"2022","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Iglesias-Sanuy, P., L\u00f3pez-Ardao, J.C., Rodr\u00edguez-P\u00e9rez, M., Herrer\u00eda-Alonso, S., Su\u00e1rez-Gonz\u00e1lez, A., and Rodr\u00edguez-Rubio, R.F. (2022). An Efficient Location-Based Forwarding Strategy for Named Data Networking and LEO Satellite Communications. Future Internet, 14.","DOI":"10.3390\/fi14100285"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"201345","DOI":"10.1109\/ACCESS.2020.3036398","article-title":"Dynamic Backoff Collision Resolution for Massive M2M Random Access in Cellular IoT Networks","volume":"8","author":"Althumali","year":"2020","journal-title":"IEEE Access"},{"key":"ref_5","unstructured":"(2025, August 24). Non-Terrestrial Networks (NTN). Available online: https:\/\/www.3gpp.org\/technologies\/ntn-overview."},{"key":"ref_6","unstructured":"3GPP (Solutions for NR to Support Non-Terrestrial Networks (NTN), 2019). Solutions for NR to Support Non-Terrestrial Networks (NTN), TR 38.821, Version 19.0.0."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"107588","DOI":"10.1016\/j.comnet.2020.107588","article-title":"Architectures, Standardisation, and Procedures for 5G Satellite Communications: A Survey","volume":"183","author":"Guidotti","year":"2020","journal-title":"Comput. Netw."},{"key":"ref_8","unstructured":"(2020). IEEE Standard for Low-Rate Wireless Networks (Standard No. IEEE 802.15.4-2020)."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Khanafer, M., Guennoun, M., and El-Abd, M. (2024). Improved Adaptive Backoff Algorithm for Optimal Channel Utilization in Large-Scale IEEE 802.15.4-Based Wireless Body Area Networks. Future Internet, 16.","DOI":"10.3390\/fi16090313"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"7891","DOI":"10.1109\/JIOT.2019.2911683","article-title":"Transmission Early-Stopping Scheme for Anti-Jamming Over Delay-Sensitive IoT Applications","volume":"6","author":"Halloush","year":"2019","journal-title":"IEEE Internet Things J."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1049\/cmu2.12516","article-title":"A Cross-Layer Anti-Jamming Method in Satellite Internet","volume":"17","author":"Yan","year":"2023","journal-title":"IET Commun."},{"key":"ref_12","first-page":"1","article-title":"Physical-layer Jammer Detection in Multi-hop IoT Networks","volume":"10","author":"Mostafa","year":"2023","journal-title":"IEEE Internet Things J."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"012063","DOI":"10.1088\/1742-6596\/2625\/1\/012063","article-title":"A Resource Optimization for Two-Step Random Access in 5G New Radio","volume":"2625","author":"Liu","year":"2023","journal-title":"J. Phys. Conf. Ser."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Krummacker, D., Veith, B., Lindenschmitt, D., and Schotten, H.D. (2022, January 6\u20138). Radio Resource Sharing in 6G Private Networks: Trustworthy Spectrum Allocation for Coexistence through DLT as Core Function. Proceedings of the 1st International Conference on 6G Networking (6GNet 2022), Paris, France.","DOI":"10.1109\/6GNet54646.2022.9830407"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2334","DOI":"10.1109\/COMST.2019.2902862","article-title":"A Tutorial on UAVs for Wireless Networks: Applications, Challenges, and Open Problems","volume":"21","author":"Mozaffari","year":"2019","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/LWC.2025.3535231","article-title":"Two-Step Random Access With Message Replication for Low-Earth Orbit Satellite Networks","volume":"14","author":"Kim","year":"2025","journal-title":"IEEE Wirel. Commun. Lett."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"120","DOI":"10.1109\/MWC.2016.1500284WC","article-title":"Toward Massive Machine Type Cellular Communications","volume":"24","author":"Dawy","year":"2017","journal-title":"IEEE Wirel. Commun."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"15497","DOI":"10.1109\/JIOT.2022.3176121","article-title":"A Distributed Collaborative Entrance Defense Framework Against DDoS Attacks on Satellite Internet","volume":"9","author":"Guo","year":"2022","journal-title":"IEEE Internet Things J."}],"container-title":["Future Internet"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1999-5903\/17\/10\/454\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,3]],"date-time":"2025-10-03T04:14:05Z","timestamp":1759464845000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1999-5903\/17\/10\/454"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,10,1]]},"references-count":18,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2025,10]]}},"alternative-id":["fi17100454"],"URL":"https:\/\/doi.org\/10.3390\/fi17100454","relation":{},"ISSN":["1999-5903"],"issn-type":[{"type":"electronic","value":"1999-5903"}],"subject":[],"published":{"date-parts":[[2025,10,1]]}}}