Abstract: The present invention provides a precoding matrix indicator feedback method, a receive end, and a transmit end. The method includes: selecting, by a receive end based on a reference signal, a precoding matrix W from a codebook, where a coefficient ? is used to perform phase adjustment on ?n in W, ?n represents a phase difference between weighted values of a first antenna group and a second antenna group of a transmit end for a transmission signal from a same transmission layer, ? n ? { ? j ? ? 2 ? ? ? ? n Q } , and the first antenna group and the second antenna group belong to a same multi-antenna system; and sending, by the receive end, a precoding matrix indicator (PMI) to the transmit end. In this way, using the coefficient ? to perform the phase adjustment on ?n can increase a size of a codebook set applicable to different antenna configurations, and improve precision of the receive end to feed back a PMI.

Abstract: The present invention discloses a method for transmitting a 4-antenna precoding matrix, a user equipment, and a base station. The method includes determining a rank used for indicating the number of transmission layers, determining a first precoding matrix in a codebook set corresponding to the rank, determining a first PMI and a second PMI used for indicating the first precoding matrix, and sending the first PMI and the second PMI used for indicating the first precoding matrix to a base station.

Abstract: The present invention provides a precoding matrix indicator feedback method, a receive end, and a transmit end. The method includes: selecting, by a receive end based on a reference signal, a precoding matrix W from a codebook, where a coefficient ? is used to perform phase adjustment on ?n in W, ?n represents a phase difference between weighted values of a first antenna group and a second antenna group of a transmit end for a transmission signal from a same transmission layer, ? n ? { ? j2? ? ? n Q } , and the first antenna group and the second antenna group belong to a same multi-antenna system; and sending, by the receive end, a precoding matrix indicator (PMI) to the transmit end. In this way, using the coefficient ? to perform the phase adjustment on ?n can increase a size of a codebook set applicable to different antenna configurations, and improve precision of the receive end to feed back a PMI.

Abstract: The present disclosure provides a method for feeding back a precoding matrix indicator, a receive end and a transmit end, where the method includes: selecting, by a receive end, a precoding matrix W from a codebook based on a reference signal, where W ? [ X 1 ? ( ? 1 ) X 2 ? ( ? 2 , ? n ) ] , the ?1 and the ?2 indicate a phase difference of weighted values for signal transmission between two neighboring antennas in a first antenna group of a transmit end and a phase difference of weighted values for signal transmission between two neighboring antennas in a second antenna group of the transmit end, the ?n indicates a phase difference of weighted values for signal transmission between the first antenna group and the second antenna group, where the signal transmission between the first antenna group and the second antenna group is for a same transmission layer, ? n = ? j ? ? 2 ? ? ? ? n M , and sending, by the receive end, a precoding matrix indi

Abstract: The present disclosure provides a method for feeding back a precoding matrix indicator, a receive end and a transmit end, where the method includes: selecting, by a receive end, a precoding matrix W from a codebook based on a reference signal, where W ? [ X 1 ? ( ? 1 ) ? X 2 ? ( ? 2 , ? n ) ] , the ?1 and the ?2 indicate a phase difference of weighted values for signal transmission between two neighboring antennas in a first antenna group of a transmit end and a phase difference of weighted values for signal transmission between two neighboring antennas in a second antenna group of the transmit end, the ?n indicates a phase difference of weighted values for signal transmission between the first antenna group and the second antenna group, where the signal transmission between the first antenna group and the second antenna group is for a same transmission layer, ? n = ? j ? ? 2 ? ? ? ? n M , and sending, by the receive end, a precoding matri

Abstract: A channel state information (CSI) reporting method is provided. A reference signal is received from a base station. A precoding matrix is selected, based on the reference signal, from a codebook, where the codebook includes a precoding matrix W and W=?SV, where a matrix V is an N×? matrix, N is the number of reference signal ports, ??N, S is a row selection matrix used to select one or more row vectors from the matrix V, and ? is a constant. CSI is sent to the base station, where the CSI includes a precoding matrix indicator PMI and the PMI is corresponding to the selected precoding matrix. A suitable precoding matrix can be selected according to an interference situation, so as to select an antenna for transmitting data and power of the antenna.

Abstract: Embodiments of the present invention provide a method for feeding back channel state information, a user equipment, and a base station, to improve feedback precision of channel state information. The method includes: receiving a reference signal sent by a base station; selecting a precoding matrix W from a codebook according to the reference signal, where a column vector of the precoding matrix W may be expressed as ?[v ej?v]T, v=[1 ej?]; and sending a precoding matrix indicator PMI to the base station, where the PMI is corresponding to the selected precoding matrix W. The present invention may further improve quantization precision and achieve balance between overheads and the quantization precision. The base station performs precoding on a sent signal according to a fed back precoding matrix indicator, which can improve precoding precision, thereby improving a data transmission rate and system throughput.