Xu, Tianheng; Zhu, Jie; Xu, Yinjun; Peng, Pei; Chen, Xianfu; Wu, Qingqing; Niyato, Dusit

IEEE INTERNET OF THINGS JOURNAL

2025, 16,

Xu, Tianheng; Zhu, Jie; Xu, Yinjun; Peng, Pei; Chen, Xianfu; Wu, Qingqing; Niyato, Dusit

Nonterrestrial networks (NTNs), as one core infrastructure of the sixth-generation (6G) communication technology, integrate heterogeneous nodes, such as high Earth orbit (HEO) satellites, to achieve 3-D ubiquitous connectivity. However, NTNs face with spectrum scarcity, imposing stringent demands on spectral efficiency and interference management. To address these challenges, we propose a nonorthogonal multiple access-oriented spectrum sensing technique for uplink scenarios, where high-altitude platforms (HAPs) serve as dynamic aerial nodes for opportunistic transmission within HEO coverage. Specifically, we derive multiuser sensing thresholds to optimize detection accuracy and suppress false alarms. Numerical simulations demonstrate the technique achieves a 33.5% throughput gain over benchmarks at 10 dB and maintains satisfactory performance across primary users' varying elevation angles and transmission willingness.