Systems and methods for channel state information acquisition using a joint space-frequency subspace
Aspects of the present disclosure are directed to channel state information (CSI) acquisition and feedback where the UE estimates the channel based on a received reference signal (such as a channel state information reference signal (CSI-RS)) and calculates an appropriate precoder matrix according to the measured channel. The UE can then send a compressed version of the precoder matrix based on a set of joint space-frequency subspace vectors to the base station that can be used by the base station in order to recover the precoder matrix from the compressed version of the precoder matrix.
1 . A method comprising:
transmitting joint space-frequency subspace configuration information for use by a user equipment (UE) to determine a compressed precoder, wherein a joint space-frequency subspace indicated by the joint space-frequency subspace configuration information combines information of an antenna subspace and a frequency subspace into a single subspace.
2 . The method of claim 1 , wherein the joint space-frequency subspace configuration information comprises antenna parameter information and sub-band parameter information to determine a first set of joint space-frequency subspace vectors for use at the UE that are consistent with a second set of joint space-frequency subspace vectors known at a base station transmitting the joint space-frequency subspace configuration information.
3 . The method of claim 2 , wherein the antenna parameter information indicates at least one of:
a first number of antenna elements in an antenna in a first direction;
a second number of antenna elements in the antenna in a second direction perpendicular to the first direction;
a first oversampling factor corresponding to the first direction; or
a second oversampling factor corresponding to the second direction.
4 . The method of claim 2 , wherein the sub-band parameter information indicates at least one of:
a discrete Fourier transform (DFT) length corresponding to a number of sub-bands; or
an oversampling factor.
5 . The method of claim 1 , wherein the joint space-frequency subspace configuration information includes a set of joint space-frequency subspace vectors.
6 . A device comprising:
one or more processors; and
a non-transitory computer-readable storage medium storing programming instructions that, when executed by the one or more processors, cause the device to perform operations including:
transmitting joint space-frequency subspace configuration information for use by a user equipment (UE) to determine a compressed precoder, wherein a joint space-frequency subspace indicated by the joint space-frequency subspace configuration information combines information of an antenna subspace and a frequency subspace into a single subspace.
7 . The device of claim 6 , wherein the joint space-frequency subspace configuration information comprises antenna parameter information and sub-band parameter information to determine a first set of joint space-frequency subspace vectors for use at the UE that are consistent with a second set of joint space-frequency subspace vectors known at a base station transmitting the joint space-frequency subspace configuration information.
8 . The device of claim 7 , wherein the antenna parameter information indicates at least one of:
a first number of antenna elements in an antenna in a first direction;
a second number of antenna elements in the antenna in a second direction perpendicular to the first direction;
a first oversampling factor corresponding to the first direction; or
a second oversampling factor corresponding to the second direction.
9 . The device of claim 7 , wherein the sub-band parameter information indicates at least one of:
a discrete Fourier transform (DFT) length corresponding to a number of sub-bands; or
an oversampling factor.
10 . The device of claim 6 , wherein the joint space-frequency subspace configuration information includes a set of joint space-frequency subspace vectors.
11 . A method performed at a side of a base station, the method comprising:
receiving joint space-frequency subspace configuration information for use by a user equipment (UE) to determine a compressed precoder, wherein a joint space-frequency subspace indicated by the joint space-frequency subspace configuration information combines information of an antenna subspace and a frequency subspace into a single subspace.
12 . The method of claim 11 , wherein the joint space-frequency subspace configuration information comprises antenna parameter information and sub-band parameter information to determine a first set of joint space-frequency subspace vectors for use at the UE that are consistent with a second set of joint space-frequency subspace vectors known at the base station,
the method further comprising:
determining the first set of joint space-frequency subspace vectors based on the joint space-frequency subspace configuration information.
13 . The method of claim 12 , wherein the antenna parameter information indicates at least one of:
a first number of antenna elements in an antenna in a first direction;
a second number of antenna elements in the antenna in a second direction perpendicular to the first direction;
a first oversampling factor corresponding to the first direction; or
a second oversampling factor corresponding to the second direction.
14 . The method of claim 12 , wherein the sub-band parameter information indicates at least one of:
a discrete Fourier transform (DFT) length corresponding to a number of sub-bands; or
an oversampling factor.
15 . The method of claim 11 , wherein the joint space-frequency subspace configuration information includes a set of joint space-frequency subspace vectors.
16 . A device at a side of a base station, the device comprising:
one or more processors; and
a non-transitory computer-readable storage medium storing programming instructions that, when executed by the one or more processors, cause the device to perform operations including:
receiving joint space-frequency subspace configuration information for use by a user equipment (UE) to determine a compressed precoder, wherein a joint space-frequency subspace indicated by the joint space-frequency subspace configuration information combines information of an antenna subspace and a frequency subspace into a single subspace.
17 . The device of claim 16 , wherein the joint space-frequency subspace configuration information comprises antenna parameter information and sub-band parameter information to determine a first set of joint space-frequency subspace vectors for use at the UE that are consistent with a second set of joint space-frequency subspace vectors known at the base station, the operations further comprising:
determining the first set of joint space-frequency subspace vectors based on the joint space-frequency subspace configuration information.
18 . The device of claim 17 , wherein the antenna parameter information indicates at least one of:
a first number of antenna elements in an antenna in a first direction;
a second number of antenna elements in the antenna in a second direction perpendicular to the first direction;
a first oversampling factor corresponding to the first direction; or
a second oversampling factor corresponding to the second direction.
19 . The device of claim 17 , wherein the sub-band parameter information indicates at least one of:
a discrete Fourier transform (DFT) length corresponding to a number of sub-bands; or
an oversampling factor.
20 . The device of claim 16 , wherein the joint space-frequency subspace configuration information includes a set of joint space-frequency subspace vectors.