Power-domain collision-tolerant random access method with auxiliary beam for satellite Internet of Things: A new solution

• Published in: China communications Vol. 21; no. 8; pp. 236 - 248
• Main Authors: Yuanyuan, Xu, Ziwei, Liu, Dongming, Bian, Gengxin, Zhang
• Format: Journal Article
• Language: English
• Published: China Institute of Communications 01.08.2024
• Subjects: Array signal processing; beamforming; non-orthogonal multiple access; Propagation losses; Protocols; random access; satellite Internet of Things; Satellites; Source separation; Throughput; Uplink
• ISSN: 1673-5447
• DOI: 10.23919/JCC.ea.2023-0055.202401

There are numerous terminals in the satellite Internet of Things (IoT). To save cost and reduce power consumption, the system needs terminals to catch the characteristics of low power consumption and light control. The regular random access (RA) protocols may generate large amounts of collisions, which degrade the system throughout severally. The near-far effect and power control technologies are not applicable in capture effect to obtain power difference, resulting in the collisions that cannot be separated. In fact, the optimal design at the receiving end can also realize the condition of packet power domain separation, but there are few relevant researches. In this paper, an auxiliary beamforming scheme is proposed for power domain signal separation. It adds an auxiliary reception beam based on the conventional beam, utilizing the correlation of packets in time-frequency domain between the main and auxiliary beam to complete signal separation. The roll-off belt of auxiliary beam is used to create the carrier-to-noise ratio (CNR) difference. This paper uses the genetic algorithm to optimize the auxiliary beam direction. Simulation results show that the proposed scheme outperforms slotted ALOHA (SA) in terms of system throughput performance and without bringing terminals additional control burden.