Resource allocation for uplink grant-free access in beam-hopping based LEO satellite systems

• Published in: 高技术通讯（英文版） Vol. 29; no. 2; pp. 140 - 147
• Main Authors: ZHANG Mengying, YANG Xiumei, BU Zhiyong
• Format: Journal Article
• Language: English
• Published: Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Sciences,Shanghai 200050,P.R.China%University of Chinese Academy of Sciences,Beijing 100049,P.R.China 01.06.2023
• Subjects: low earth orbit(LEO)satellite system; grant-free access; collision; beam-hopping(BH); resource allocation
• ISSN: 1006-6748
• DOI: 10.3772/j.issn.1006-6748.2023.02.004

The low earth orbit(LEO)satellite system provides a promising solution for the global coverage of Internet of Things(IoT)services.Confronted with the sporadic uplink transmission from massive IoT ter-minals,this work investigates the grant-free access scheme and resource allocation algorithm for the beam-hopping(BH)based LEO satellite systems.To improve the packet success rate,the time slots are pre-allocated to each cell according to the number of terrestrial terminals and the probability of packet ar-rival.When the packets arrive,the terrestrial terminals perform contention-free or contention-based grant-free access with packet repetition in the time slots allocated to their cells.The analytical expression of the packet collision probability for the grant-free access scheme is derived to provide reference for the re-source allocation.To reduce the computational complexity,a heuristic resource allocation algorithm is proposed to minimize the maximum cell packet collision probability in the system.Simulation results show that the proposed resource allocation scheme achieves lower packet collision probability and higher re-source utilization ratio when compared with the uniform resource allocation scheme.