Patent Description:
Aspects of the present disclosure generally relate to wireless communication, and more particularly to techniques and apparatuses for user equipment (UE) override or improvement for enhanced type-II channel state information (CSI).

<CIT>, relates to channel state information in a wireless communication system for reference signal resources. <CIT>, relates to a method and apparatus for designing a broadcast channel, e.g. group common or cell common, for a new radio access technology (NR) in a wireless communication system.

In some aspects, a method of wireless communication, performed by a user equipment (UE), may include determining that an enhanced type-II channel state information (CSI) report configuration, associated with transmitting CSI feedback to a base station, is to be overridden; and transmitting, based at least in part on determining that the enhanced type-II CSI report configuration is to be overridden, a CSI report using another CSI report configuration, wherein the CSI report includes the CSI feedback and an indication that the enhanced type-II CSI report configuration has been overridden.

In some aspects, a UE for wireless communication may include memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to determine that an enhanced type-II CSI report configuration, associated with transmitting CSI feedback to a base station, is to be overridden; and transmit, based at least in part on determining that the enhanced type-II CSI report configuration is to be overridden, a CSI report using another CSI report configuration, wherein the CSI report includes the CSI feedback and an indication that the enhanced type-II CSI report configuration has been overridden.

In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a UE, may cause the one or more processors to determine that an enhanced type-II CSI report configuration, associated with transmitting CSI feedback to a base station, is to be overridden; and transmit, based at least in part on determining that the enhanced type-II CSI report configuration is to be overridden, a CSI report using another CSI report configuration, wherein the CSI report includes the CSI feedback and an indication that the enhanced type-II CSI report configuration has been overridden.

In some aspects, an apparatus for wireless communication may include means for determining that an enhanced type-II CSI report configuration, associated with transmitting CSI feedback to a base station, is to be overridden; and means for transmitting, based at least in part on determining that the enhanced type-II CSI report configuration is to be overridden, a CSI report using another CSI report configuration, wherein the CSI report includes the CSI feedback and an indication that the enhanced type-II CSI report configuration has been overridden.

In some aspects, a method of wireless communication, performed by a UE, may include determining that an identity matrix is to be used as a frequency domain basis for an enhanced type-II CSI report configuration associated with transmitting CSI feedback to a base station; and transmitting a CSI report using the identity matrix as the frequency domain basis for the enhanced type-II CSI report configuration.

In some aspects, a UE for wireless communication may include memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to determine that an identity matrix is to be used as a frequency domain basis for an enhanced type-II CSI report configuration associated with transmitting CSI feedback to a base station; and transmit a CSI report using the identity matrix as the frequency domain basis for the enhanced type-II CSI report configuration.

In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a UE, may cause the one or more processors to determine that an identity matrix is to be used as a frequency domain basis for an enhanced type-II CSI report configuration associated with transmitting CSI feedback to a base station; and transmit a CSI report using the identity matrix as the frequency domain basis for the enhanced type-II CSI report configuration.

In some aspects, an apparatus for wireless communication may include means for determining that an identity matrix is to be used as a frequency domain basis for an enhanced type-II CSI report configuration associated with transmitting CSI feedback to a base station; and means for transmitting a CSI report using the identity matrix as the frequency domain basis for the enhanced type-II CSI report configuration.

Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and processing system as substantially described herein with reference to and as illustrated by the accompanying drawings and specification.

In this case, UE <NUM> may perform scheduling operations, resource selection operations, and/or other operations described elsewhere herein as being performed by the base station <NUM>.

Controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform one or more techniques associated with UE override and/or improvement for enhanced type-II CSI, as described in more detail elsewhere herein. For example, controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform or direct operations of, for example, process <NUM> of <FIG>, process <NUM> of <FIG>, and/or other processes as described herein. Memories <NUM> and <NUM> may store data and program codes for base station <NUM> and UE <NUM>, respectively.

In some aspects, UE <NUM> may include means for determining that an enhanced type-II CSI report configuration, associated with transmitting CSI feedback to a base station, is to be overridden; means for transmitting, based at least in part on determining that the enhanced type-II CSI report configuration is to be overridden, a CSI report using another CSI report configuration, wherein the CSI report includes the CSI feedback and an indication that the enhanced type-II CSI report configuration has been overridden; and/or the like. In some aspects, such means may include one or more components of UE <NUM> described in connection with <FIG>.

In some aspects, UE <NUM> may include means for determining that an identity matrix is to be used as a frequency domain basis for an enhanced type-II CSI report configuration associated with transmitting CSI feedback to a base station; means for transmitting a CSI report using the identity matrix as the frequency domain basis for the enhanced type-II CSI report configuration; and/or the like. In some aspects, such means may include one or more components of UE <NUM> described in connection with <FIG>.

A BS (e.g., BS <NUM>) may transmit many beams to a UE (e.g., UE <NUM>). For example, the BS may generate the beams using an antenna panel that generates beams at a spatial and/or phase displacement from each other. The BS and the UE may select a set of beams that are to be used for communication between the BS and the UE. For example, the set of beams transmitted from the BS to the UE may be referred to herein as a communication link, a downlink, and/or the like. The communication link between the BS and the UE may propagate in a medium and/or through various geometric paths, which are collectively referred to herein as a channel between the BS and the UE.

In some aspects, the UE may select a set of beams for communication with the BS. For example, the UE may select the set of beams based at least in part on the set of beams being associated with favorable characteristics (e.g., a satisfactory receive power, a satisfactory signal to interference plus noise (SINR) value, etc.). The UE may generate a codeword that indicates the set of beams and parameters to be used for using a codebook based at least in part on performing channel estimation of the channel between the BS and the UE.

One such codebook is the type-II codebook, prescribed in <NUM>/NR. The type-II codebook may use a two-stage procedure to generate the codeword: a first stage wherein the set of beams is selected for a wideband of the communication link (e.g., sometimes referred to herein as W1), and a second stage wherein linear combination is performed, for a set of subbands, using the set of beams for each set of subbands. The codeword may be based at least in part on the linear combination, and may indicate the set of beams and/or respective amplitudes, phase coefficients, and/or the like. Thus, the UE may provide an indication of channel state at the UE and may request the set of beams to be used for the UE. The type-II codebook may provide more precise specification of the channel state than a type-I codebook, which may provide a predefined codeword-based approach to specifying selected beams. Thus, the type-II codebook may be referred to as a high resolution codebook in comparison to the type-I codebook. The type-II codebook may improve multi-user multiple input multiple output (MU-MIMO) performance on the communication link.

For one type of type-II codebook (e.g., the codebook specified in Release <NUM> of the 3GPP standard for <NUM>/NR), the precoder of the codebook is based at least in part on a linear combination of discrete Fourier transform (DFT) beams. The linear combination may define the precoder W as W = W<NUM>W<NUM>, wherein the spatial domain compression matrix <MAT>, wherein <MAT> are L spatial domain basis vectors of dimension N<NUM>N<NUM> × <NUM> (mapped to the two polarizations, so <NUM> in total), P = <NUM>N<NUM>N<NUM> indicates a number of dimensions (sometimes represented as D), and the combination coefficient matrix W<NUM> is composed of K = <NUM>Lυ linear combination coefficients, where υ indicates a total number of layers. Each column in W<NUM> indicates the linear combination of complex coefficients (i.e., amplitude and phase) for one layer, wherein the amplitude coefficient is given by <MAT> for l = <NUM>,. , v - <NUM>, and <MAT> and <MAT> are the wideband and subband coefficients, respectively. The phase coefficient is given by <MAT> for l = <NUM>,. , v - <NUM>, and ci is one of the <NUM> phase shift keying (8PSK) or the quadrature phase shift keying (QPSK) constellation points.

The UE may report the above values and/or other values associated with channel estimation using channel state information (CSI) feedback. CSI feedback for the type-II codebook may include two parts: a first part, sometimes referred to as CSI part I, and a second part, sometimes referred to as CSI part II. In some cases, the first part may have a smaller payload than the second part, and/or may have a fixed payload. For example, the first part may have a payload size of less than approximately <NUM> bits, whereas the second part may have a variable payload size that may be dependent on the first part. In some cases, the second part may have a payload size of approximately <NUM> bits to <NUM> bits, although other values may be used.

In some cases, the first part may identify one or more of: a rank indicator (RI) (e.g., <NUM> bit to indicate one layer υ = <NUM> or two layers υ = <NUM> when the configured maximum rank is <NUM>); wideband and subband differential channel quality indicators (CQI), for which a total payload size may be dependent on the number of subbands (e.g., approximately <NUM> + <NUM> × <NUM> = <NUM> bits for <NUM> subbands); an indication of the number of non-zero wideband amplitude coefficients Ql for each layer; and/or the like. In some cases, the second part may identify one or more of: wideband and/or subband precoding matrix indicators (PMIs) including a spatial basis vector selection indication; wideband and subband amplitude coefficients; subband phase coefficients; and/or the like.

In some cases, the type-II CSI feedback may use a compressed type-II precoder. This may reduce overhead of type-II CSI feedback. The compressed precoder may exploit the sparsity of the spatial domain and/or the frequency domain. For example, an example of a compressed type-II precoder W is given by W = <MAT>, wherein the precoder matrix W has P = <NUM>N<NUM>N<NUM> rows (representing the spatial domain and the number of ports) and N<NUM> columns (wherein N<NUM> is a frequency-domain compression unit of resource blocks or reporting subbands). The W<NUM> matrix, described above, is the spatial basis consisting of L beams per polarization group (hence a total of <NUM> beams). The W̃<NUM> matrix indicates all of the required linear combination complex coefficients (amplitude and co-phasing), similarly to what is described above. The Wf matrix is composed of the basis vectors used to perform compression in frequency domain, Wf = [f<NUM> f<NUM>. fM-<NUM>], where <MAT> are M size-N<NUM> × <NUM> orthogonal DFT vectors for each spatial basis i = <NUM>,. , <NUM> - <NUM>. The above type-II CSI feedback may be referred to in some cases as enhanced or modified type-II CSI feedback (e.g., enhanced relative to an approach that does not use basis vectors in the spatial and frequency domains to compress feedback size).

The CSI feedback for this enhanced type-II CSI feedback may include a spatial domain basis vector selection that is similar to the approach described in connection with the type-II CSI feedback configuration. The CSI feedback may further include a frequency-domain (FD) basis subset selection (wherein M out of a total N<NUM> basis vectors are selected). In some cases, common FD basis vectors for all the <NUM> spatial beams may be used, which is referred to herein as Alternative <NUM>. In these cases, M basis vectors are dynamically selected and reported. The value of M may be configured by the network or reported by the UE. In other cases, referred to herein as Alternative <NUM>, independent FD basis vectors may be used for each spatial domain basis vector, with potentially different numbers and/or selections of FD basis vectors for each spatial domain basis vector. The total number of FD basis vectors across all the <NUM>L spatial beams may be configured.

The enhanced type-II CSI feedback may further include the FD coefficients (e.g., amplitude and phase) in W̃<NUM>. For Alternative <NUM> (the common FD basis vector subset selection), the enhanced type-II CSI feedback may report only a subset K<NUM> < K = 2LM of the coefficients. For Alternative <NUM> (the independent basis subset selection), the enhanced type-II CSI feedback may report <MAT> amplitude and phase coefficients, wherein Mi is the number of FD basis vectors associated with one spatial beam.

A variety of quantization and reporting options may be used, two examples of which are provided below. As a first example, for each of the K or K<NUM> FD coefficients, the enhanced type-II CSI feedback may use <NUM>-bit amplitude and QPSK or 8PSK phase. As a second example, the enhanced type-II CSI feedback may report a <NUM>-bit wideband amplitude for each beam or spatial domain basis vector, a <NUM>-bit or <NUM>-bit differential amplitude for each FD coefficient, and a QPSK or 8PSK phase bit.

However, in some cases, it may be desirable for the UE to override and/or alter a configuration that would otherwise cause the UE to transmit CSI feedback using the conventional enhanced type-II CSI report configuration described above. For example, if a configured number of FD basis vectors and/or a number of coefficients is insufficient, reconstruction performance may be degraded if the actual channel delay spread is significant. As a particular example, if a precoder comprises a large delay spread, a power of the precoder may not be well captured by the configured number of FD basis vectors and/or the number of coefficients. Thus, in some cases, it may be desirable for the UE to override the CSI report such that the UE uses a CSI report configuration other than the conventional enhanced type-II CSI report configuration. Similarly, in some cases, it may be desirable for the UE to use an improved type-II CSI report configuration rather than the conventional enhanced type-II CSI report configuration.

Some techniques and apparatuses described herein provide UE override for enhanced type-II CSI. In some aspects, the UE may determine that an enhanced type-II CSI report configuration, associated with transmitting CSI feedback to a base station, is to be overridden, and may transmit a CSI report using another CSI report configuration. In some aspects, in such a case, the CSI report may include the CSI feedback and an indication that the enhanced type-II CSI report configuration has been overridden. Additionally, some techniques and apparatuses described herein provide an improved enhanced type-II CSI report configuration. In some aspects, the UE may determine that an identity matrix is to be used as a frequency domain basis for an enhanced type-II CSI report configuration associated with transmitting CSI feedback to a base station (e.g., rather than using a DFT matrix as the frequency basis), and may transmit a CSI report using the identity matrix as the frequency domain basis. In the case of either the override of the enhanced type-II CSI report configuration or use of the improved enhanced type-II CSI report configuration, communication performance between the UE and the BS is improved based at least in part on improved accuracy in reporting of CSI feedback.

<FIG> is a diagram illustrating an example <NUM> of UE override for enhanced type-II CSI, in accordance with various aspects of the present disclosure. As shown, example <NUM> includes a UE <NUM> and a BS <NUM> that are associated with a communication link. As further shown, the communication link may be associated with a channel. For example, the communication link may be referred to as the channel, or may propagate via the channel.

As shown in <FIG>, and by reference number <NUM>, BS <NUM> may transmit a reference signal transmission to UE <NUM>. The reference signal transmission may include, for example, a CSI reference signal, a demodulation reference signal, and/or the like. As shown by reference number <NUM>, UE <NUM> may perform CSI measurements on the reference signal transmission. For example, UE <NUM> may perform channel estimation or another operation based at least in part on the reference signal transmissions in order to determine CSI feedback.

As shown by reference number <NUM>, UE <NUM> may determine that an enhanced type-II CSI report configuration, associated with transmitting the CSI feedback to BS <NUM>, is to be overridden. For example, UE <NUM> may be configured with a codebook indicating that UE <NUM> is to use the enhanced type-II CSI report configuration in association with transmitting a CSI report to BS <NUM>. However, in some aspects, as indicated by reference number <NUM>, UE <NUM> may determine that UE <NUM> is to override the enhanced type-II CSI report configuration.

In some aspects, UE <NUM> may determine that the enhanced type-II CSI report configuration is to be overridden based at least in part on determining that a metric, associated with the enhanced type-II CSI report configuration, is inferior to a metric associated with a type-I CSI report configuration. For example, UE <NUM> may be configured with the type-I CSI report configuration. Here, based at least in part on the CSI measurements performed by UE <NUM>, UE <NUM> may compute a metric for the enhanced type-II CSI report configuration and a comparable metric for the type-I CSI report configuration. In this example, if the metric associated with the enhanced type-II CSI report configuration is inferior to (e.g., less than by a threshold amount) the metric associated with the type-I CSI report configuration, then UE <NUM> may determine that UE <NUM> is to override the enhanced type-II CSI report configuration. In some aspects, the metric used by UE <NUM> to make this determination may include a signal to noise ratio (SNR), a capacity metric, a channel quality indicator (CQI), and/or the like.

In some aspects, UE <NUM> may determine that the enhanced type-II CSI report configuration is to be overridden based at least in part on determining that a difference between a metric, associated with the enhanced type-II CSI report configuration, and a metric associated with a type-II CSI report configuration satisfies a threshold. For example, UE <NUM> may be configured with the type-II CSI report configuration. Here, based at least in part on the CSI measurements performed by UE <NUM>, UE <NUM> may compute a metric for the enhanced type-II CSI report configuration and a comparable metric for the type-II CSI report configuration. In this example, if a difference between the metric associated with the enhanced type-II CSI report configuration and the metric associated with the type-II CSI report configuration, then UE <NUM> may determine that UE <NUM> is to override the enhanced type-II CSI report configuration. In some aspects, the metric used by UE <NUM> to make this determination may include, for example, an SNR, a capacity metric, a CQI, and/or the like. In some aspects, the threshold may be predefined on UE <NUM> (e.g., in accordance with an applicable 3GPP Standard), or may be configured on UE <NUM> (e.g., by BS <NUM>).

In some aspects, UE <NUM> may determine that the enhanced type-II CSI report configuration is to be overridden based at least in part on a condition configured on or determined by UE <NUM>. The condition may include, for example, a determination by UE <NUM> that a configured parameter (e.g., a configured number of FD basis vectors, a configured number of coefficients, and/or the like) fails to satisfy a threshold (e.g., is less than a particular number) and/or is otherwise determined to be insufficient to a particular degree.

As shown by reference number <NUM>, UE <NUM> may transmit, based at least in part on determining that the enhanced type-II CSI report configuration is to be overridden, a CSI report using another CSI report configuration. As shown, the CSI report may include the CSI feedback and an indication that the enhanced type-II CSI report configuration has been overridden.

In some aspects, UE <NUM> may include the indication that the enhanced type-II CSI report configuration has been overridden by including a particular combination of values (e.g., one or more unused and/or invalid values) in the CSI report. For example, UE <NUM> may include the indication in the CSI report by including, in the CSI report, a particular combination of one or more unused and/or invalid rank indicators (RI), one or more unused and/or invalid precoding matrix indicators (PMI), one or more unused and/or invalid channel quality indicators (CQI), and/or the like. In such a case, the use of the particular combination may indicate, to BS <NUM>, that the enhanced type-II CSI report configuration has been overridden.

As an example, in some aspects, UE <NUM> may include the indication that the enhanced type-II CSI report configuration has been overridden in the CSI report by using an out of range (OOR) CQI included the CSI report. In such a case, the use of the OOR CQI may indicate, to BS <NUM>, that the enhanced type-II CSI report configuration has been overridden.

As another example, in some aspects, UE <NUM> may include the indication that the enhanced type-II CSI report configuration has been overridden in the CSI report by using a dedicated PMI included in the CSI report. For example, the dedicated PMI may identify a number of FD basis vectors as zero, a number of coefficients as zero, amplitudes of all coefficients as zero, and/or the like. In such a case, the use of the dedicated PMI may indicate, to BS <NUM>, that the enhanced type-II CSI report configuration has been overridden.

As another example, in some aspects, UE <NUM> may include the indication that the enhanced type-II CSI report configuration has been overridden using an indication that an identity matrix has been selected as a frequency domain basis (e.g., (e.g., by including a dedicated basis selection indication that indicates that an identity matrix was selected as the frequency domain basis). In such a case, the other CSI report configuration used by UE <NUM> is an enhanced type-II CSI report configuration using the identity matrix as the frequency domain basis. In some aspects, the use of the identity matrix results in per subband level reporting in the CSI report. Additional detail regarding selection and use of the identity matrix as the frequency domain basis are provided below with regard to <FIG> and <FIG>.

In some aspects, UE <NUM> may include the indication that the enhanced type-II CSI report configuration has been overridden by including an addition in the CSI report (e.g., an additional item of information that would otherwise not be included in the CSI report). In some aspects, the addition may include, for example, one or more bits added to the CSI report. In such a case, the addition to the CSI report may indicate, to BS <NUM>, that the enhanced type-II CSI report configuration has been overridden.

In some aspects, UE <NUM> may include the indication that the enhanced type-II CSI report configuration has been overridden in part <NUM> of the CSI report and/or in part <NUM> of the CSI report.

In some aspects, the enhanced type-II CSI report configuration may be associated with a different codebook than that of the other CSI report configuration (i.e., the CSI report configuration with which UE <NUM> overrides the enhanced type-II CSI report configuration). For example, the enhanced type-II CSI report configuration may be associated with a first codebook configured on UE <NUM>, and the other CSI report configuration may be associated with a second codebook configured on UE <NUM>. In such a case, in some aspects, the other CSI report configuration may be a type-II CSI report configuration that is associated with the second codebook. For example, when the first codebook comprises Release <NUM> Type-II CSI reporting, the other report configuration may be associated with a codebook that comprises Release <NUM> Type-II CSI reporting. As another example, when the first codebook comprises Release <NUM> Type-II CSI reporting, the other report configuration may be associated with a codebook that comprises Release <NUM> Type-II CSI reporting. Alternatively, the other CSI report configuration may be a type-I CSI report configuration that is associated with the second codebook.

In some aspects, the other CSI report configuration is a simplified enhanced type-II CSI report configuration. In other words, UE <NUM> may be configured with a simplified enhanced type-II CSI report configuration (e.g., a configuration that uses fewer and/or simpler parameters, matrices, and/or the like), and may override the enhanced type-II CSI report configuration using the simplified enhanced type-II CSI report configuration.

In some aspects, the other CSI report configuration is a modified enhanced type-II CSI report configuration. In other words, UE <NUM> may be configured with a modified enhanced type-II CSI report configuration (e.g., a configuration that uses different and/or alternate parameters, matrices, and/or the like), and may override the enhanced type-II CSI report configuration using the modified enhanced type-II CSI report configuration.

In some aspects, when using the other CSI report configuration in association with transmitting the CSI report, UE <NUM> may override one or more parameters of the other CSI report configuration. For example, UE <NUM> may override a quantization level, a spatial domain basis vector, a subband size, and/or another parameter of the other CSI report configuration when transmitting the CSI report.

In some aspects, based at least in part on the other CSI report configuration, UE <NUM> may include information associated with a single coefficient and/or information associated with a single basis in the CSI report. For example, the other CSI report configuration may indicate that information associated with a single coefficient and/or information associated with a single basis is to be included in the CSI report, and UE <NUM> may transmit the CSI report according to the other CSI report configuration. In some aspects, the information associated with the single coefficient may include information that identifies the single coefficient or information that identifies a location of a strongest coefficient (e.g., such that the CSI report includes information associated with the single coefficient and/or the single basis).

In some aspects, based at least in part on the other CSI report configuration, UE <NUM> may include only a spatial domain compression matrix (W1) in the CSI report. For example, the other CSI report configuration may indicate that only a spatial domain compression matrix is to be included in the CSI report, and UE <NUM> may transmit the CSI report according to the other CSI report configuration (e.g., such that the CSI report includes only W1).

In some aspects, based at least in part on the other CSI report configuration, UE <NUM> may not include CSI part II in the CSI report. For example, the other CSI report configuration may indicate that CSI part II is not to be included in the CSI report, and UE <NUM> may transmit the CSI report according to the other CSI report configuration (e.g., such that the CSI report does not include part II).

As shown by reference number <NUM>, BS <NUM> (and/or UE <NUM>) may perform communication on the communication link based at least in part on the CSI feedback included in the CSI report. For example, BS <NUM> may receive the CSI report, and may generate one or more beamformed beams for UE <NUM> using phase and amplitude FD coefficients, one or more spatial domain basis vectors, one or more frequency domain basis vectors, and/or other information included in the CSI feedback.

In this way, UE <NUM> may override enhanced type-II CSI in order to improve accuracy in reporting of CSI feedback (e.g., in a case when the conventional enhanced type-II CSI report configuration is insufficient), thereby improving communication performance between UE <NUM> and BS <NUM>.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process <NUM> is an example where a UE (e.g., UE <NUM>) performs override for enhanced type-II CSI.

As shown in <FIG>, in some aspects, process <NUM> may include determining that an enhanced type-II CSI report configuration, associated with transmitting CSI feedback to a base station, is to be overridden (block <NUM>). For example, the UE may determine (e.g., using antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, and/or the like) that an enhanced type-II CSI report configuration, associated with transmitting CSI feedback to a base station, is to be overridden, as described above.

As shown in <FIG>, in some aspects, process <NUM> may include transmitting, based at least in part on determining that the enhanced type-II CSI report configuration is to be overridden, a CSI report using another CSI report configuration (block <NUM>). For example, the UE may transmit (e.g., using antenna <NUM>, MOD <NUM>, TX MIMO processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, and/or the like), based at least in part on determining that the enhanced type-II CSI report configuration is to be overridden, a CSI report using another CSI report configuration, as described above. In some aspects, the CSI report includes the CSI feedback and an indication that the enhanced type-II CSI report configuration has been overridden.

Process <NUM> may include additional aspects, such as any single aspect and/or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.

In a first aspect, the determination that the enhanced type-II CSI report configuration is to be overridden is made based at least in part on determining that a metric, associated with the enhanced type-II CSI report configuration, is inferior to a metric associated with a type-I CSI report configuration.

In a second aspect, alone or in combination with the first aspect, the metric associated with the enhanced type-II CSI report configuration and the metric associated with the type-I CSI report configuration include at least one of: a signal to noise ratio (SNR); a capacity metric; or a channel quality indicator (CQI).

In a third aspect, alone or in combination with any one or more of the first and second aspects, the determination that the enhanced type-II CSI report configuration is to be overridden is made based at least in part on determining that a difference between a metric, associated with the enhanced type-II CSI report configuration, and a metric associated with a type-II CSI report configuration, satisfies a threshold.

In a fourth aspect, alone or in combination with any one or more of the first through third aspects, the metric associated with the enhanced type-II CSI report configuration and the metric associated with the type-II CSI report configuration include at least one of: a signal to noise ratio (SNR); a capacity metric; or a channel quality indicator (CQI).

In a fifth aspect, alone or in combination with any one or more of the first through fourth aspects, the threshold is predefined on the UE.

In a sixth aspect, alone or in combination with any one or more of the first through fifth aspects, the threshold is configured on the UE by the base station.

In a seventh aspect, alone or in combination with any one or more of the first through sixth aspects, the determination that the enhanced type-II CSI report configuration is to be overridden is made based at least in part on an override condition configured on or determined by the UE.

In an eighth aspect, alone or in combination with any one or more of the first through seventh aspects, the indication that the enhanced type-II CSI report configuration has been overridden is included in the CSI report using a combination of unused or invalid values associated with at least one of: a rank indicator (RI); a precoding matrix indicator (PMI); or a channel quality indicator (CQI).

In a ninth aspect, alone or in combination with any one or more of the first through eighth aspects, the indication that the enhanced type-II CSI report configuration has been overridden is an out of range (OOR) channel quality indicator (CQI) included the CSI report.

In a tenth aspect, alone or in combination with any one or more of the first through ninth aspects, the indication that the enhanced type-II CSI report configuration has been overridden is a dedicated precoding matrix indicator (PMI) included in the CSI report.

In an eleventh aspect, alone or in combination with any one or more of the first through tenth aspects, the dedicated PMI identifies a number of frequency domain (FD) basis vectors as zero or a number of coefficients as zero.

In a twelfth aspect, alone or in combination with any one or more of the first through eleventh aspects, the dedicated PMI identifies amplitudes of all coefficients as zero.

In a thirteenth aspect, alone or in combination with any one or more of the first through twelfth aspects, the indication that the enhanced type-II CSI report configuration has been overridden is included in the CSI report using an addition to the CSI report.

In a fourteenth aspect, alone or in combination with any one or more of the first through thirteenth aspects, the addition includes one or more bits in the CSI report.

In a fifteenth aspect, alone or in combination with any one or more of the first through fourteenth aspects, the indication that the enhanced type-II CSI report configuration has been overridden is included in part I of the CSI report.

In a sixteenth aspect, alone or in combination with any one or more of the first through fifteenth aspects, the indication that the enhanced type-II CSI report configuration has been overridden is included in part II of the CSI report.

In a seventeenth aspect, alone or in combination with any one or more of the first through sixteenth aspects, the enhanced type-II CSI report configuration is associated with a first codebook configured on the UE, and the other CSI report configuration is associated with a second codebook configured on the UE.

In an eighteenth aspect, alone or in combination with any one or more of the first through seventeenth aspects, the other CSI report configuration is a type-II CSI report configuration associated with the second codebook.

In a nineteenth aspect, alone or in combination with any one or more of the first through eighteenth aspects, the other CSI report configuration is a type-I CSI report configuration associated with the second codebook.

In a twentieth aspect, alone or in combination with any one or more of the first through nineteenth aspects, the other CSI report configuration is a simplified enhanced type-II CSI report configuration.

In a twenty-first aspect, alone or in combination with any one or more of the first through twentieth aspects, the other CSI report configuration is a modified type-II CSI report configuration.

In a twenty-second aspect, alone or in combination with any one or more of the first through twenty-first aspects, one or more parameters, associated with the other CSI report configuration, are overridden in the CSI report.

In a twenty-third aspect, alone or in combination with any one or more of the first through twenty-second aspects, based at least in part on the other CSI report configuration, the CSI report includes information associated with a single coefficient and information associated with a single basis.

In a twenty-fourth, alone or in combination with any one or more of the first through twenty-third aspects, the information associated with the single coefficient includes information that identifies the single coefficient.

In a twenty-fifth aspect, alone or in combination with any one or more of the first through twenty-fourth aspects, the information associated with the single coefficient includes information that identifies a location of a strongest coefficient.

In a twenty-sixth aspect, alone or in combination with any one or more of the first through twenty-fifth aspects, based at least in part on the other CSI report configuration, the CSI report includes only a spatial domain compression matrix (W1).

In a twenty-seventh aspect, alone or in combination with any one or more of the first through twenty-sixth aspects, based at least in part on the other CSI report configuration, the CSI report does not include part II. In a twenty-eighth aspect, alone or in combination with any one or more of the first through twenty-seventh aspects, the indication that the enhanced type-II CSI report configuration has been overridden is an indication that an identity matrix has been selected as a frequency domain basis, where the other CSI report configuration is an enhanced type-II CSI report configuration using the identity matrix as the frequency domain basis.

In a twenty-ninth aspect, alone or in combination with any one or more of the first through twenty-eighth aspects, the use of the identity matrix results in per subband level reporting in the CSI report.

In a thirtieth aspect, alone or in combination with any one or more of the first through twenty-ninth aspects, the identity matrix is used based at least in part on determining that a metric, associated with using a DFT matrix as the frequency basis, is inferior to a metric associated with using the identity matrix as the frequency basis.

In a thirty-first aspect, alone or in combination with any one or more of the first through thirtieth aspects, the metric associated with using the DFT matrix as the frequency basis and the metric associated with using the identity matrix include at least one of: a SNR; a capacity metric; or a CQI.

In a thirty-second aspect, alone or in combination with any one or more of the first through thirty-first aspects, the identity matrix is used based at least in part on determining that a difference between a metric associated with using a DFT matrix as the frequency basis, and a metric associated with using the identity matrix as the frequency basis, satisfies a threshold.

In a thirty-third aspect, alone or in combination with any one or more of the first through thirty-second aspects the metric associated with using the DFT matrix as the frequency basis and the metric associated with using the identity matrix include at least one of: a SNR; a capacity metric; or a CQI.

In a thirty-fourth aspect, alone or in combination with any one or more of the first through thirty-third aspects the threshold is predefined on the UE.

In a thirty-fifth aspect, alone or in combination with any one or more of the first through thirty-fourth aspects the threshold is configured on the UE by the base station.

In a thirty-sixth aspect, alone or in combination with any one or more of the first through thirty-fifth aspects the determination that the identity matrix is to be used is made based at least in part on a selection condition configured on or determined by the UE.

As shown by reference number <NUM>, UE <NUM> may determine that an identity matrix is to be used as a frequency domain basis for an enhanced type-II CSI report configuration associated with transmitting CSI feedback to BS <NUM>. For example, UE <NUM> may be configured with a codebook indicating that UE <NUM> is to use the enhanced type-II CSI report configuration in association with transmitting a CSI report to BS <NUM>. However, as indicated by reference number <NUM>, UE <NUM> may determine that UE <NUM> is to use an identity matrix as a frequency basis for the enhanced type-II CSI report configuration, in some aspects.

In some aspects, UE <NUM> may determine that UE <NUM> is to use the identity matrix as the frequency basis for the enhanced type-II CSI report configuration based at least in part on determining that a metric, associated with using a DFT matrix as the frequency basis for the enhanced type-II CSI report configuration, is inferior to a metric associated with using the identity matrix as the frequency basis for the enhanced type-II CSI report configuration. For example, based at least in part on the CSI measurements performed by UE <NUM>, UE <NUM> may compute a metric for the enhanced type-II CSI report configuration using the identity matrix as the frequency basis and a comparable metric for the enhanced type-II CSI report configuration using the DFT matrix as the frequency basis. In this example, if the metric associated with using the DFT matrix is inferior to (e.g., less than, by a threshold amount) the metric associated with the identity matrix, then UE <NUM> may determine that UE <NUM> is to use the identity matrix as the frequency basis for the enhanced type-II CSI report configuration. In some aspects, the metric used by UE <NUM> to make this determination may include a signal to noise ratio (SNR), a capacity metric, a channel quality indicator (CQI), and/or the like.

In some aspects, UE <NUM> may determine that UE <NUM> is to use the identity matrix as the frequency basis for the enhanced type-II CSI report configuration based at least in part on determining that a difference between a metric associated with using a DFT matrix as the frequency basis for the enhanced type-II CSI report configuration, and a metric associated with using the identity matrix as the frequency basis for the enhanced type-II CSI report configuration, satisfies a threshold. For example, based at least in part on the CSI measurements performed by UE <NUM>, UE <NUM> may compute a metric for the enhanced type-II CSI report configuration using the identity matrix as the frequency basis and a comparable metric for the enhanced type-II CSI report configuration using the DFT matrix as the frequency basis. In this example, if a difference between the metric associated using the DFT matrix and the metric associated with using the identity matrix satisfies a threshold, then UE <NUM> may determine that UE <NUM> is to use the identity matrix as the frequency basis for the enhanced type-II CSI report configuration. In some aspects, the metric used by UE <NUM> to make this determination may include, for example, an SNR, a capacity metric, a CQI, and/or the like. In some aspects, the threshold may be predefined on UE <NUM> (e.g., in accordance with an applicable 3GPP standard), or may be configured on UE <NUM> (e.g., by BS <NUM>).

In some aspects, UE <NUM> may determine that UE <NUM> is to use the identity matrix as the frequency basis for the enhanced type-II CSI report configuration based at least in part on a condition configured on or determined by UE <NUM>. The condition may include, for example, a determination by UE <NUM> that a configured parameter (e.g., a configured number of FD basis vectors, a configured number of coefficients, and/or the like) fails to satisfy a threshold (e.g., is less than a particular number) and/or is otherwise determined to be insufficient to a particular degree.

As shown by reference number <NUM>, UE <NUM> may transmit a CSI report using the identity matrix as the frequency domain basis for the enhanced type-II CSI report configuration. In some aspects, the use of the identity matrix results in per subband level reporting in the CSI report (e.g., rather than a frequency domain compressed version of CSI reporting). In some aspects, UE <NUM> may transmit the CSI report in a manner similar to that described above in association with <FIG>.

As shown by reference number <NUM>, BS <NUM> (and/or UE <NUM>) may perform communication on the communication link based at least in part on the CSI feedback. For example, BS <NUM> may generate one or more beamformed beams for UE <NUM> using phase and amplitude FD coefficients, one or more spatial domain basis vectors, one or more frequency domain basis vectors, and/or other information included in the CSI feedback.

In this way, UE <NUM> may use an improved enhanced type-II CSI report configuration in order to improve accuracy in reporting of CSI feedback (e.g., in a case when the conventional enhanced type-II CSI report configuration is insufficient), thereby improving communication performance between UE <NUM> and BS <NUM>.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process <NUM> is an example where a UE (e.g., UE <NUM>) performs improvement of enhanced type-II CSI.

As shown in <FIG>, in some aspects, process <NUM> may include determining that an identity matrix is to be used as a frequency domain basis for an enhanced type-II CSI report configuration associated with transmitting CSI feedback to a base station (block <NUM>). For example, the UE may determine (e.g., using antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, and/or the like) that an identity matrix is to be used as a frequency domain basis for an enhanced type-II CSI report configuration associated with transmitting CSI feedback to a base station, as described above.

As shown in <FIG>, in some aspects, process <NUM> may include transmitting a CSI report using the identity matrix as the frequency domain basis for the enhanced type-II CSI report configuration (block <NUM>). For example, the UE may transmit (e.g., using antenna <NUM>, MOD <NUM>, TX MIMO processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, and/or the like) a CSI report using the identity matrix as the frequency domain basis for the enhanced type-II CSI report configuration, as described above.

Process <NUM> may include additional aspects, such as any single aspect and/or any combination of aspects described herein and/or in connection with one or more other processes described elsewhere herein.

In a first aspect, the use of the identity matrix results in per subband level reporting in the CSI report.

In a second aspect, alone or in combination with any one or more of the first and second aspects, the determination that the identity matrix is to be used is made based at least in part on determining that a metric, associated with using a DFT matrix as the frequency basis, is inferior to a metric associated with using the identity matrix as the frequency basis.

In a third aspect, alone or in combination with any one or more of the first and second aspects, the metric associated with using the DFT matrix as the frequency basis and the metric associated with using the identity matrix include at least one of: a SNR; a capacity metric; or a CQI.

In a fourth aspect, alone or in combination with any one or more of the first through third aspects, the determination that the identity matrix is to be used is made based at least in part on determining that a difference between a metric associated with using a DFT matrix as the frequency basis, and a metric associated with using the identity matrix as the frequency basis, satisfies a threshold.

In a fifth aspect, alone or in combination with any one or more of the first through fourth aspects, the metric associated with using the DFT matrix as the frequency basis and the metric associated with using the identity matrix include at least one of: a SNR; a capacity metric; or a CQI.

In a sixth aspect, alone or in combination with any one or more of the first through fifth aspects, the threshold is predefined on the UE.

In a seventh aspect, alone or in combination with any one or more of the first through sixth aspects, the threshold is configured on the UE by the base station.

In an eighth aspect, alone or in combination with any one or more of the first through seventh aspects, the determination that the identity matrix is to be used is made based at least in part on a selection condition configured on or determined by the UE.

Claim 1:
A method (<NUM>) of wireless communication performed by a user equipment, UE (<NUM>), comprising:
determining (<NUM>, <NUM>) that an enhanced type-II channel state information, CSI, report configuration, associated with transmitting CSI feedback to a base station, is to be overridden; and
transmitting (<NUM>, <NUM>), based at least in part on determining that the enhanced type-II CSI report configuration is to be overridden, a CSI report using another CSI report configuration,
wherein the CSI report includes the CSI feedback and an indication that the enhanced type-II CSI report configuration has been overridden, and
wherein the indication that the enhanced type-II CSI report configuration has been overridden is included in the CSI report using a combination of unused or invalid values associated with at least one of:
a rank indicator, RI;
a precoding matrix indicator, PMI; or
a channel quality indicator, CQI.