Before revision:  With the growing complexity of CSI  in massive MIMO system , traditional compressive sensing based CSI feedback has become a bottleneck problem that is limited in piratical . Recently, numerous deep learning based CSI feedback approaches demonstrate the efficiency and potential.
After revision:  With the growing complexity of CSI in massive MIMO system has become a bottleneck problem, the traditional compressive sensing based CSI feedback has become a bottleneck problem that is limited in piratical . Recently, numerous deep learning based CSI feedback approaches demonstrate the efficiency and potential.