National Mobile Communications Research Laboratory Southeast University Nanjing 210096 P.R.China;
National Mobile Communications Research Laboratory Southeast University Nanjing 210096 P.R.China;
National Mobile Communications Research Laboratory Southeast University Nanjing 210096 P.R.China;
National Mobile Communications Research Laboratory Southeast University Nanjing 210096 P.R.China;
Sparse array; Reconfigurable intelligent surface; Multi-user; Blockage-free; mmWave;