Channel information feedback method and apparatus thereof

A channel information feedback method, adapted in a transmitting end of a multiuser multiple input multiple output (MU MIMO) system, comprising:

• performing power allocation and beamforming on multiple user data to be transmitted to a plurality of users of the MU MIMO system by the transmitting end according to a plurality of quantized subspace matrices and a plurality of quantized auxiliary information matrices received from a plurality of receiving ends of the MU MIMO system, so as to generate a transmitting signal;
• and
• transmitting the transmitting signal to the receiving ends,
• wherein each one of the receiving ends obtains a subspace matrix and a magnitude matrix related to the transmitting end according to a channel matrix corresponding to the receiving end, and performs a first quantization and a second quantization on the subspace matrix and an auxiliary information matrix to generate a quantized subspace matrix and a quantized auxiliary information matrix, the receiving ends feed back the quantized subspace matrices and the quantized auxiliary information matrices to the transmitting end through an uplink channel, wherein the auxiliary information matrix is related to the magnitude matrix and a residual subspace matrix, and the residual subspace matrix includes residual subspace information of the subspace matrix remained after the first quantization is performed on the subspace matrix.

A channel information feedback apparatus, adapted in a receiving end of a multiuser multiple input multiple output (MU MIMO) system, comprising:

• a transmitting end-related extractor device, configured for obtaining a subspace matrix and a magnitude matrix related to a transmitting end of the MU MIMO system according to a channel matrix corresponding to the receiving end;
• a first quantizer, configured for performing a first quantization on the subspace matrix to generate a quantized subspace matrix;
• a second quantizer, configured for performing a second quantization on an auxiliary information matrix to generate a quantized auxiliary information matrix, wherein the auxiliary information matrix is related to the magnitude matrix and a residual subspace matrix, and the residual subspace matrix includes residual subspace information of the subspace matrix remained after the first quantization is performed on the subspace matrix;
• and
• a feedback signal transmitter, configured for feeding back the quantized subspace matrix and the quantized auxiliary information matrix to the transmitting end through an uplink channel.

A transmitting end, adapted in a multiuser multiple input multiple output (MU MIMO) system, comprising:

• a feedback signal receiver, configured for receiving a plurality of quantized subspace matrices and a plurality of quantized auxiliary information matrices fed back by a plurality of receiving ends of a plurality of users of the MU MIMO system through an uplink channel;
• a power allocation device, configured for performing power allocation on multiple user data to be transmitted to the users of the MU MIMO system by the transmitting end according to the quantized subspace matrices and the quantized auxiliary information matrices;
• and
• a beamforming device, configured for performing beamforming on the multiple user data which are power-allocated according to the quantized subspace matrices and the quantized auxiliary information matrices, so as to generate a transmitting signal to the receiving ends,
• wherein each one of the receiving ends obtains a subspace matrix and a magnitude matrix related to the transmitting end according to a channel matrix corresponding to the receiving end, and performs a first quantization and a second quantization on the subspace matrix and an auxiliary information matrix to generate a quantized subspace matrix and a quantized auxiliary information matrix, the receiving ends feed back the quantized subspace matrices and the quantized auxiliary information matrices to the transmitting end through the uplink channel, wherein the auxiliary information matrix is related to the magnitude matrix and a residual subspace matrix, and the residual subspace matrix has residual subspace information of the subspace matrix remained after the first quantization is performed on the subspace matrix.

A multiuser multiple input multiple output (MU MIMO) system, comprising:

• a plurality of receiving ends, corresponding to a plurality of users of the MU MIMO system, wherein each one of the receiving ends comprises a channel information feedback apparatus, and the channel information feedback apparatus comprises:
• a transmitting end-related extractor device, configured for obtaining a subspace matrix and a magnitude matrix related to a transmitting end of the MU MIMO system according to a channel matrix corresponding to the receiving end;
• a first quantizer, configured for performing a first quantization on the subspace matrix to generate a quantized subspace matrix;
• a second quantizer, configured for performing a second quantization on an auxiliary information matrix to generate a quantized auxiliary information matrix, wherein the auxiliary information matrix is related to the magnitude matrix and a residual subspace matrix, and the residual subspace matrix includes residual subspace information of the subspace matrix remained after the first quantization is performed on the subspace matrix;
• and
• a feedback signal transmitter, configured for feeding back the quantized subspace matrix and the quantized auxiliary information matrix to the transmitting end through an uplink channel;
• and
• the transmitting end, comprising:
• a feedback signal receiver, configured for receiving the quantized subspace matrix and the quantized auxiliary information matrix through the uplink channel;
• a power allocation device, configured for performing power allocation on multiple user data to be transmitted to the users of the MU MIMO system by the transmitting end according to the quantized subspace matrices and the quantized auxiliary information matrices;
• a beamforming device, configured for performing beamforming on the multiple user data which are power-allocated according to the quantized subspace matrices and the quantized auxiliary information matrices, so as to generate a transmitting signal to the receiving ends.