Channel state information feedback method, device, terminal, and network side, and storage medium

A method for feeding back channel state information (CSI), comprising:

• transmitting beamformed channel state information reference signals (CSI-RSs) or the beamformed CSI-RSs and frequency domain basis vector indication information to a terminal by means of antenna ports;
• wherein beams used in beamforming are determined based on spatial domain basis vectors or based on the spatial domain basis vectors and frequency domain basis vectors, and the spatial domain basis vectors and the frequency domain basis vectors are determined based on an uplink channel;
• receiving port indication information and port combination coefficients for data transmission fed back by the terminal;
• wherein the port indication information and the port combination coefficients are determined by the terminal based on the beamformed CSI-RSs, or the beamformed CSI-RSs and frequency domain basis vector indication information;
• and
• determining precoding of the downlink transmission data based on the port indication information and the port combination coefficients.

A terminal, comprising a memory, a processor, and a program stored in the memory and executable on the processor, wherein the program, when being executed on the processor, causes the processor to implement the following steps:

• receiving beamformed channel state information reference signals (CSI-RSs) or the beamformed CSI-RSs and frequency domain basis vector indication information transmitted by a network side by means of antenna ports;
• wherein beams used in beamforming are determined based on spatial domain basis vectors, or based on the spatial domain basis vectors and frequency domain basis vectors, and the spatial domain basis vectors and the frequency domain basis vectors are determined based on an uplink channel;
• determining port indication information and port combination coefficients for data transmission based on the beamformed CSI-RSs, or the beamformed CSI-RSs and the frequency domain basis vector indication information;
• and
• feeding back the port indication information and the port combination coefficients to the network side for determining precoding of downlink transmission data based on the port indication information and the port combination coefficients at the network side.