Channel state information feedback method and apparatus

User equipment, comprising:

• a processor and a transmitter, wherein the processor is connected to the transmitter by using a communications bus;
• the processor configured to determine a Pre-coding Matrix Indicator (PMI) and a Channel Quality Information (CQI) that need to be fed back, and a feedback expression manner of the PMI and the CQI, wherein the feedback expression manner refers to a manner used to express the PMI and the CQI when the user equipment feeds back the PMI and the CQI, and the feedback expression manner comprises at least a first feedback expression manner or a second feedback expression manner;
• the transmitter, coupled to the processor by using the communications bus, configured to send the PMI and the CQI to a network device in the feedback expression manner determined by the processor, wherein:
• the first feedback expression manner comprises:
• using T CQI values to express CQI of M codewords, and using one PMI value to indicate one PMI, wherein T and M are integers, wherein T is less than M and is greater than or equal to 1, M is greater than or equal to 2, and at least one CQI value of the T CQI values can express channel quality information of at least two codewords, and
• the second feedback expression manner comprises:
• using M CQI values to express CQI of M codewords, and using one PMI value to indicate one PMI, wherein a bit quantity of at least one CQI value of the M CQI values is less than 3, and a bit quantity of at least one CQI value is greater than 3;
• and
• wherein in any downlink physical resource block (PRB) pair that corresponds to the PMI and the CQI, any codeword of the M codewords is mapped on different downlink subcarriers to a same layer.

A network device, comprising:

• a transmitter, configured to send antenna configuration information to user equipment, wherein the antenna configuration information is used by the user equipment to determine, according to a quantity of configured antennas that is comprised in the antenna configuration information, a Pre-coding Matrix Indicator (PMI) and a Channel Quality Information (CQI) that need to be fed back, and a feedback expression manner of the PMI and the CQI, and send the PMI and the CQI to the network device in the determined feedback expression manner;
• a processor, connected to the transmitter by using a communications bus, configured to determine the feedback expression manner of the PMI and the CQI according to a quantity of configured antennas that is comprised in the antenna configuration information, wherein the transmitter is further configured to send the feedback expression manner, determined by the processor, of the PMI and the CQI to the user equipment;
• a receiver, connected to the processor by using the communications bus, and configured to receive the PMI and the CQI that are fed back by the user equipment in the feedback expression manner of the PMI and the CQI, wherein the feedback expression manner refers to a manner used to express the PMI and the CQI when the user equipment feeds back the PMI and the CQI, and the feedback expression manner comprises at least a first feedback expression manner or a second feedback expression manner, wherein:
• the first feedback expression manner comprises:
• using T CQI values to express CQI of M codewords, and using one PMI value to indicate one PMI, wherein T and M are integers, wherein T is less than M and is greater than or equal to 1, M is greater than or equal to 2, and at least one CQI value of the T CQI values can express channel quality information of at least two codewords, and
• the second feedback expression manner comprises:
• using M CQI values to express CQI of M codewords, and using one PMI value to indicate one PMI, wherein a bit quantity of at least one CQI value of the M CQI values is less than 3, and a bit quantity of at least one CQI value is greater than 3;
• and
• wherein in any downlink physical resource block PRB pair that corresponds to the PMI and the CQI, any codeword of the M codewords is mapped on different downlink subcarriers to a same layer.