Eigenvalue Based Active User Enumeration for Grant-Free Access Under Carrier Frequency Offsets
<|reference_start|>Eigenvalue Based Active User Enumeration for Grant-Free Access Under Carrier Frequency Offsets: This paper investigates a grant-free non-orthogonal multiple access (GF-NOMA) system in the presence of carrier frequency offsets. We propose two schemes for enumerating active users in such a GF-NOMA system, which is equivalent to estimating the sparsity level. Both schemes utilize a short common pilot and the eigenvalues of the sample covariance matrix of the received signal. The two schemes differ in their treatment of noise variance: one exploits known variance information, while the other is designed to function without this knowledge. Simulation results demonstrate the effectiveness of the proposed schemes in terms of the normalized mean-squared error.<|reference_end|>
@article{hara2024eigenvalue,
    title={Eigenvalue Based Active User Enumeration for Grant-Free Access Under
  Carrier Frequency Offsets},
    author={Takanori Hara},
    journal={arXiv preprint arXiv:2408.05988},
    year={2024},
    archivePrefix={arXiv},
    eprint={2408.05988},
    primaryClass={cs.IT eess.SP math.IT}
}