Asymptotic Capacity Results for Non-Stationary Time-Variant Channels Using Subspace Projections
<|reference_start|>Asymptotic Capacity Results for Non-Stationary Time-Variant Channels Using Subspace Projections: In this paper we deal with a single-antenna discrete-time flat-fading channel. The fading process is assumed to be stationary for the duration of a single data block. From block to block the fading process is allowed to be non-stationary. The number of scatterers bounds the rank of the channels covariance matrix. The signal-to-noise ratio (SNR), the user velocity, and the data block-length define the usable rank of the time-variant channel subspace. The usable channel subspace grows with the SNR. This growth in dimensionality must be taken into account for asymptotic capacity results in the high-SNR regime. Using results from the theory of time-concentrated and band-limited sequences we are able to define an SNR threshold below which the capacity grows logarithmically. Above this threshold the capacity grows double-logarithmically.<|reference_end|>
@article{zemen2005asymptotic,
    title={Asymptotic Capacity Results for Non-Stationary Time-Variant Channels
  Using Subspace Projections},
    author={Thomas Zemen (1), Stefan M. Moser (2) ((1) ftw. Forschungszentrum
  Telekommunikation Wien, (2) Signal and Information Processing Laboratory ETH
  Zurich)},
    journal={arXiv preprint arXiv:cs/0505020},
    year={2005},
    archivePrefix={arXiv},
    eprint={cs/0505020},
    primaryClass={cs.IT math.IT}
}