@article{passiverisvshybridrisacomparativestudy,
  title = {Passive RIS vs.Hybrid RIS: A Comparative Study on Channel Estimation},
  author = {Rafaela Schroeder and Jiguang He and Markku Juntti},
  year = {2020},
  eprint = {2010.06981},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2010.06981v3},
}