Towards Bridging the Gap between Near and Far-Field Characterizations of the Wireless Channel
<|reference_start|>Towards Bridging the Gap between Near and Far-Field Characterizations of the Wireless Channel: The "near-field" propagation modeling of wireless channels is necessary to support sixth-generation (6G) technologies, such as intelligent reflecting surface (IRS), that are enabled by large aperture antennas and higher frequency carriers. As the conventional far-field model proves inadequate in this context, there is a pressing need to explore and bridge the gap between near and far-field propagation models. Although far-field models are simple and provide computationally efficient solutions for many practical applications, near-field models provide the most accurate representation of wireless channels. This paper builds upon the foundations of electromagnetic wave propagation theory to derive near and far-field models as approximations of the Green's function (Maxwell's equations). We characterize the near and far-field models both theoretically and with the help of simulations in a line-of-sight (LOS)-only scenario. In particular, for two key applications in multiantenna systems, namely, beamforming and multiple-access, we showcase the advantages of using the near-field model over the far-field, and present a novel scheduling scheme for multiple-access in the near-field regime. Our findings offer insights into the challenge of incorporating near-field models in practical wireless systems, fostering enhanced performance in future communication technologies.<|reference_end|>
@article{agrawal2024towards,
    title={Towards Bridging the Gap between Near and Far-Field Characterizations of
  the Wireless Channel},
    author={Navneet Agrawal and Ehsan Tohidi and Renato L. G. Cavalcante and
  S{l}awomir Sta'nczak},
    journal={arXiv preprint arXiv:2402.16755},
    year={2024},
    archivePrefix={arXiv},
    eprint={2402.16755},
    primaryClass={cs.IT eess.SP math.IT}
}