@ARTICLE{ding2016nonorthogonal,
  author={W. {Ding} and F. {Yang} and S. {Liu} and X. {Wang} and J. {Song}},
  journal={IEEE Transactions on Vehicular Technology}, 
  title={Nonorthogonal Time–Frequency Training-Sequence-Based CSI Acquisition for MIMO Systems}, 
  year={2016},
  volume={65},
  number={7},
  pages={5714-5719},
  doi={10.1109/TVT.2015.2463716}}