Csi feedback method and apparatus, terminal, network side device, and medium

A CSI feedback method, comprising:

• sending, by a network-side device, configuration information for channel state information CSI to a terminal, wherein part or all of information associated with the configuration information is selected for CSI feedback;
• and
• receiving, by the network-side device, the CSI fed back by the terminal, the CSI fed back comprising information related to the selected information, wherein
• a precoding matrix indicated by the CSI fed back is a product of at least two submatrices, and a dimension of at least one of the at least two submatrices is determined based on the selected information.

A terminal, comprising a processor and a memory, wherein the memory stores a program or instructions capable of running on the processor, and when the program or instructions are executed by the processor, a CSI feedback method is implemented, the CSI feedback method comprising:

• receiving from a network-side device, configuration information for channel state information CSI;
• and
• selecting from information associated with the configuration information, part or all of the information for CSI feedback, the CSI fed back comprising information related to the selected information, wherein
• a precoding matrix indicated by the CSI fed back is a product of at least two submatrices, and a dimension of at least one of the at least two submatrices is determined based on the selected information.