Channel state information feedback method, terminal device, and network device

A network device, comprising:

• a processor;
• and
• a non-transitory computer-readable storage medium coupled to the processor and storing programming instructions for execution by the processor, the programming instructions instruct the processor to carry out a method comprising:
• sending a downlink reference signal based on a dimension reduction matrix, wherein a first dimension of the dimension reduction matrix is the same as a quantity of transmit antenna ports of the network device, and a second dimension of the dimension reduction matrix is less than the first dimension of the dimension reduction matrix;
• receiving a vector information of an eigenvector of a downlink equivalent channel of the downlink reference signal from a terminal device;
• and
• determining a precoding matrix based on the dimension reduction matrix and the vector information.

A terminal device, comprising:

• a processor;
• and
• a non-transitory computer-readable storage medium coupled to the processor and storing programming instructions for execution by the processor, the programming instructions instruct the processor to carry out a method comprising:
• receiving a downlink reference signal from a network device;
• obtaining a dimension reduction matrix based on the downlink reference signal, wherein a first dimension of the dimension reduction matrix is the same as a quantity of transmit antenna ports of the network device, and a second dimension of the dimension reduction matrix is less than the first dimension of the dimension reduction matrix;
• and
• sending vector information of an eigenvector of a downlink equivalent channel according to the dimension reduction matrix to the network device.