Uplink precoding method in 4-Tx system
AssigneeLG Electronics Inc.
InventorsMoon II Lee, Wook Bong Lee, Jae Hoon Chung, Hyun Soo Ko, Bin Chul Ihm
Life of this patent
Estimating the term…
Abstract
A method for a user equipment to precode and transmit an uplink signal efficiently in a 4-antenna system and a method for a base station to receive the transmitted signal efficiently are disclosed. Four antennas of a user equipment can be grouped by a 2-antenna unit. In consideration of this antenna group, it is able to perform precoding using antenna selection/DFT matrix of the antenna group unit. Moreover, a rank-3 codebook can be configured to include a precoding matrix of a type in consideration of power balance per antenna and a precoding matrix including one non-zero component only in one row for maintaining a good CM property.
Claims21
A method of transmitting a signal, which is transmitted to a base station by a user equipment configured to use 4 antennas, the method comprising:
- obtaining transmission rank information;
- outputting a precoded signal by precoding a number of layer signals, the number corresponding to a transmission rank included in the transmission rank information, using a specific precoding matrix corresponding to the transmission rank, wherein the specific precoding matrix is selected from a 4-antenna codebook;
- and
- transmitting the precoded signal to the base station,
- wherein the 4 antennas are grouped into a first antenna group including two of the 4 antennas and a second antenna group including the other two of the 4 antennas, and
- wherein the 4-antenna codebook includes a first type precoding matrix, in which two components corresponding to one of the first and second antenna groups are zero and two components corresponding to the other one of the first and second antenna groups construct a discrete Fourier transform (DFT) matrix, and a second type precoding matrix, in which two components corresponding to the first antenna group and two components corresponding to the second antenna group construct DFT matrixes for a rank of 1.
A method of transmitting a signal, which is transmitted to a base station by a user equipment configured to use 4 antennas grouped into a first antenna group including two of the 4 antennas and a second antenna group including the other two of the 4 antennas, the method comprising:
- turning off the first antenna group in a specific situation;
- and
- transmitting the signal to the base station via the second antenna group,
- wherein turning off the first antenna group is performed by precoding using a rank-1 precoding matrix, and
- wherein the rank-1 precoding matrix includes a precoding matrix, in which two components corresponding to the first antenna group are zero and two components corresponding to the second antenna group construct a discrete Fourier transform (DFT) matrix.
A method of receiving a signal, which is received by a base station from a user equipment configured to use 4 antennas, the method comprising:
- receiving a reception signal from the user equipment;
- obtaining a transmission rank and precoding matrix identification information used by the user equipment for the reception signal;
- and
- performing reverse processing of precoding on the reception signal using a specific precoding matrix corresponding to the transmission rank and precoding matrix identification information selected from a 4-antenna codebook,
- wherein the 4 antennas are grouped into a first antenna group including two of the 4 antennas and a second antenna group including the other two of the 4 antennas, and
- wherein the 4-antenna codebook includes a first type precoding matrix, in which two components corresponding to one of the first and second antenna groups are zero and two components corresponding to the other one of the first and second antenna groups construct a discrete Fourier transform (DFT) matrix, and a second type precoding matrix, in which two components corresponding to the first antenna group and two components corresponding to the second antenna group construct DFT matrixes for a rank of 1.
A user equipment in a wireless communication system, comprising:
- a first antenna group including a first antenna and a second antenna;
- a second antenna group including a third antenna and a fourth antenna;
- a memory configured to store a 4-antenna codebook including a first type precoding matrix, in which two components corresponding to one of the first and second antenna groups are zero and two components corresponding to the other one of the first and second antenna groups construct a discrete Fourier transform (DFT) matrix, and a second type precoding matrix, in which two components corresponding to the first antenna group and two components corresponding to the second antenna group construct DFT matrixes for a rank of 1;
- and
- a precoder outputting a precoded signal by precoding a number of layer signals, the number corresponding to a transmission rank, using a specific precoding matrix corresponding to the transmission rank, wherein the specific precoding matrix is selected from the 4-antenna codebook stored in the memory,
- wherein the precoded signal is transmitted to a base station via at least the first antenna group or the second antenna group.
A user equipment comprising:
- a first antenna group including a first antenna and a second antenna;
- a second antenna group including a third antenna and a fourth antenna;
- a memory configured to store a 4-antenna codebook including a precoding matrix to turn off the first antenna group for a rank of 1;
- and
- a precoder outputting a precoded signal by precoding a transmission signal using the precoding matrix,
- wherein the precoded signal is transmitted to a base station via the first antenna group, and
- wherein the precoding matrix includes two components corresponding to the first antenna group that are zero and another two components corresponding to the second antenna group that construct a discrete Fourier transform (DFT) matrix.
A base station comprising:
- an antenna configured to receive a reception signal transmitted from a user equipment configured to transmit a signal using 4 antennas grouped into a first antenna group including two of the 4 antennas and a second antenna group including the other two of the 4 antennas;
- a memory configured to store a 4-antenna codebook including a first type precoding matrix, in which two components corresponding to one of the first and second antenna groups are zero and two components corresponding to the other one of the first and second antenna groups construct a discrete Fourier transform (DFT) matrix, and a second type precoding matrix, in which two components corresponding to the first antenna group and two components corresponding to the second antenna group construct DFT matrixes for a rank of 1;
- and
- a precoder performing reverse processing of precoding on the reception signal by using a specific precoding matrix corresponding to a transmission rank and precoding matrix identification information used by the user equipment, wherein the specific precoding matrix is selected from the 4-antenna codebook.
Dependencies are inferred from the claim text.