@article{wang_gao_jin_lin_2019, 
  title={An Overview of Enhanced Massive MIMO with Array Signal Processing Techniques}, 
  DOI={10.1109/jstsp.2019.2934931}, 
  publisher={Institute of Electrical and Electronics Engineers (IEEE)}, 
  author={Wang, Mingjin and Gao, Feifei and Jin, Shi and Lin, Hai}, 
  year={2019}
  }