Patent Description:
<NUM>/NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT)), and other requirements. <NUM>/NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra reliable low latency communications (URLLC). Some aspects of <NUM>/NR may be based on the <NUM> Long Term Evolution (LTE) standard. There exists a need for further improvements in <NUM>/NR technology. <CIT>, relates to a signaling sending method.

A channel state feedback procedure may include a first device (e.g., a user equipment (UE)) receiving a channel state information reference signal (CSI-RS) from a second device (e.g., a base station) and transmitting a CSI report to the second device including, for example, channel conditions for the reference signals received at the first device. In some examples, determining the CSI report may include selecting a precoding matrix indicator (PMI). In some examples, a majority of the CSI report determination process may be utilized by the PMI selection. However, accurate PMI selection is beneficial, especially as the quantity of antennas in a system increases. PMI selection may include selecting a wideband component W<NUM> and a subband component W<NUM>.

Example techniques disclosed herein facilitate adaptive precoder updating for channel state feedback. For example, techniques disclosed herein facilitate dynamically determining whether to reuse a first wideband component W<NUM> of a first PMI for a second wideband component W<NUM>, whether to select the second wideband component W<NUM> from a wideband component codebook, and/or whether to select the second wideband component W<NUM> from a subset of the wideband component codebook. In some examples, the determining of whether to reuse the first wideband component W<NUM> for the second wideband component W<NUM> may be based on one or more conditions associated with the first wideband component W<NUM>, a first CSI-RS associated with the first wideband component W<NUM>, the first PMI, a second CSI-RS, and/or conditions associated with the UE. By dynamically determining whether to reuse the first wideband component W<NUM>, techniques disclosed herein may increase power/cycle savings without introducing performance degradation.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided according to the claims <NUM>, <NUM>, <NUM>.

As used herein, the term computer-readable medium is expressly defined to include any type of computer readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media. As used herein, "computer-readable medium," "machine-readable medium," "computer-readable memory," and "machine-readable memory" are used interchangeably.

The base stations <NUM> configured for <NUM> LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC <NUM> through backhaul links <NUM> (e.g., S1 interface). The base stations <NUM> configured for <NUM>/NR (collectively referred to as Next Generation RAN (NG-RAN)) may interface with core network <NUM> through backhaul links <NUM>. The base stations <NUM> may communicate directly or indirectly (e.g., through the EPC <NUM> or core network <NUM>) with each other over backhaul links <NUM> (e.g., X2 interface).

Referring again to <FIG>, in certain aspects, the UE <NUM> may be configured to manage one or more aspects of wireless communication via adaptive precoder updating for channel state feedback. As an example, in <FIG>, the UE <NUM> may include a precoder selection component <NUM> configured to select a second wideband component W<NUM> of a second PMI, the second PMI to include the second wideband component W<NUM> and a second subband component W<NUM>,. The precoder selection component <NUM> may also be configured to select the second wideband component W<NUM> based at least on a determining of whether to reuse for the second wideband component W<NUM> a first wideband component W<NUM> of a first PMI previously determined based on a received first CSI-RS, and the first PMI to include a first wideband component W<NUM> and a first subband component W<NUM>,. The precoder selection component <NUM> may also be configured to determine the second PMI based on a received second CSI-RS, the second wideband component W<NUM>, and the second subband component W<NUM>, and to report the determined second PMI to a base station.

Although the following description may provide examples based on NR channel state feedback, it should be appreciated that the concepts described herein may be applicable to other communication technologies. For example, the concepts described herein may be applicable to LTE, LTE-A, CDMA, GSM, and/or other wireless technologies (or RATs) in which one or more reference signals and/or reports may be exchanged.

Accordingly, for slot configuration <NUM> and numerology µ, there are <NUM> symbols/slot and 2µ slots/subframe. The subcarrier spacing is <NUM> and symbol duration is approximately <NUM>.

At least one of the TX processor <NUM>, the RX processor <NUM>, and/or the controller/processor <NUM> of the UE <NUM> may be configured to perform aspects in connection with the precoder selection component <NUM> of <FIG>.

In response to receiving a CSI-RS, a UE may measure various radio channel conditions and report the measurements to a base station (e.g., may perform the channel state feedback procedure). For example, after receiving the CSI-RS, the UE may generate a CSI report including one or more components, such as channel quality information (CQI), a layer indicator (LI), a rank indicator (RI), and a PMI (sometimes referred to as a "precoder").

In some examples, the PMI may be selected from a codebook (or dictionary). In some examples, the codebook may be predetermined (e.g., as provided by a standard). In NR, a dual stage codebook may be used for determining the precoder. For example, a UE may use Equation <NUM> (below) to determine a precoder.

In Equation <NUM>, (W) represents the precoder, (W<NUM>) represents a wideband component, and (W<NUM>) represents a subband component. The wideband component W<NUM> represents the wideband or long-term properties of the channel. The subband component W<NUM> represents the subband or short-term properties of the channel. For example, the subband component W<NUM> may useful for determining beam selection and/or co-phasing of polarization. In some examples, the subband component W<NUM> may correspond to a portion of a frequency band, while the wideband component W<NUM> may correspond to the frequency band.

In some examples, the wideband component W<NUM> may be represented using Equation <NUM> (below)<MAT>.

In Equation <NUM>, the wideband component W<NUM> may be represented via a block diagonal matrix in which B represents a set of vectors corresponding to oversampled 2D DFT beams.

Using the wideband component W<NUM> and the subband component W<NUM>, the UE may then determine the PMI. In some examples, the precoding matrix for Type <NUM> may be represented using Equation <NUM> (below).

In Equation <NUM>, (v) denotes the layers, (N<NUM>) represents the number of CSI-RS ports in the horizontal dimension, and (N<NUM>) represents the number of CSI-RS ports in the vertical dimension.

While PMI selection may include finding the corresponding matrix (or matrices) in the codebook, performing the PMI selection is a complicated process, especially for the UE. For example, as the number of antennas increases, the complexity of finding the precoder increases because the size of the codebook also increases. However, accurate PMI selection is beneficial, especially as the number of antennas increases at the base station, as the throughput delta between selecting the optimal precoder verses selecting an incorrect precoder may be substantial.

In some examples, the majority of the complexity in determining the CSI report may be driven by finding the correct precoder (e.g., up at <NUM>% of the complexity). As described above, the wideband component W<NUM> corresponds to the long-term or wideband properties of the frequency band. Accordingly, the main complexity of performing the precoder selection may be due to the selection of the wideband component W<NUM> due to, for example, the relatively large size of the corresponding codebook.

In some examples, transmissions of CSI-RS may have relatively high periodicity (e.g., once every <NUM> slots or every <NUM> units at <NUM> sub-carrier spacing (SCS)). Performing PMI selection, and, in particular, selection of the wideband component W<NUM>, each time a CSI-RS is received, may lead to high power/cycle consumption. However, in some instances, updating the wideband component W<NUM> may not provide benefits that substantially outweigh the costs of performing the wideband component W<NUM> selection. For example, in relatively low mobility instances, where channel change is relatively insignificant and the CSI-RS uses a same identifier as a previous CSI-RS (e.g., to confirm that this is not a first CSI-RS), the UE may be able to update the wideband component W<NUM> less frequently than the CSI-RS periodicity.

Example techniques disclosed herein facilitate opportunistically determining when to update the wideband component W<NUM> and/or to reuse a previous wideband component W<NUM> when determining a PMI. In some examples, the UE may measure properties associated with the CSI-RS, the previous PMI, and/or the UE when selecting the wideband component W<NUM>. For example, the UE may measure and/or determine properties such as channel condition, mobility, Rx/Tx beam configuration, TCI state, and/or quality of the determination of the last PMI update when selecting the current wideband component W<NUM>. In certain such examples, the UE may determine whether one or more of the properties satisfy corresponding thresholds when determining the current wideband component W<NUM>. For example, if based on measurements, the UE determines that the UE has relatively low mobility, the channel condition is relatively good, the quality of the determination of the last PMI update was relatively good, and the current CSI-RS has properties that are the same as the previous CSI-RS (e.g., the same identifier, the same beam configuration, and/or the same TCI state), then the UE may determine to skip updating the wideband component W<NUM> and to reuse the previous wideband component W<NUM>. However, if the UE determines that one or more of the properties are not satisfactory, then the UE may determine to update the wideband component W<NUM>.

In some examples, the UE may apply tiers of thresholding when determining whether the one or more properties are satisfactory and select the wideband component W<NUM> based on the thresholding. The UE first determines whether the properties of the current CSI-RS and the previous CSI-RS are the same (e.g., the same identifier, the same beam configuration, and/or the same TCI state) and whether the quality of the determination of the last PMI update satisfies a threshold quality. In certain such examples, if the UE determines that the properties of the current CSI-RS and the previous CSI-RS are not the same (e.g., one or more of the identifier, the beam configuration, and/or the TCI state is not the same) and/or the quality of the determination of the last PMI update does not satisfy the threshold quality, then the UE may determine to update the wideband component W<NUM>.

However, if the UE determines that the properties are the same and the quality of the determination of the last PMI update satisfies the threshold quality, then the UE may compare the mobility of the UE and/or the channel condition (e.g., of reference signals received at the UE) to one or more respective thresholds when selecting the current wideband component W<NUM>. For example, the UE may compare the mobility and the channel condition to a first set of thresholds. The UE may then determine to skip updating the current wideband component W<NUM> (e.g., reuse the previous wideband component W<NUM>) when the mobility and the channel condition satisfy the first set of thresholds. In some examples, in response to determining that the first set of thresholds is not satisfied (e.g., the mobility does not satisfy the corresponding first threshold and/or the channel condition does not satisfy the corresponding first threshold), the UE may compare the mobility and the channel condition to a second set of thresholds. In certain such examples, if the UE determines that the second set of thresholds are satisfied, the UE may select the current wideband component W<NUM> from a subset of the codebook used to select the wideband component W<NUM>. And, if the UE determines that the second set of thresholds are not satisfied (e.g., the mobility does not satisfy the corresponding second threshold and/or the channel condition does not satisfy the corresponding second threshold), then the UE may determine to select the current wideband component W<NUM> from the full codebook.

It should be appreciated that while the above example described two sets of thresholds, in other examples, any suitable quantity of thresholds may be used.

By utilizing the techniques disclosed herein, the UE may dynamically determine when to update the wideband component W<NUM> and/or to reuse the previous wideband component W<NUM>. By dynamically determining when to update, the techniques disclosed herein facilitate updating the wideband component W<NUM> less frequently than the CSI-RS periodicity, which may enable conserving power/cycle consumption.

Furthermore, in some examples, two different precoders may alternate in being characterized as being the "best" precoder, while offering the same benefit (or relatively same benefits) as the other. In certain such examples, if the UE were to select the precoder each time the CSI-RS is received, the UE may "ping-pong" between the two precoders. However, by utilizing the techniques disclosed herein, if the UE determines that properties associated with the current CSI-RS and the previous CSI-RS are relatively the same, then the UE can forego updating the wideband component W<NUM> (e.g., use the previous wideband component W<NUM>) and avoid "ping-ponging" between two precoders, resulting in a relatively more stable precoder selection.

<FIG> illustrates an example of wireless communication <NUM> between a base station <NUM> and a UE <NUM>, as presented herein. One or more aspects of the base station <NUM> may be implemented by the base station <NUM>/<NUM> of <FIG> and/or the base station <NUM> of <FIG>. One or more aspects of the UE <NUM> may be implemented by the UE <NUM> of <FIG> and/or the UE <NUM> of <FIG>.

It should be appreciated that while the wireless communication <NUM> includes one base station <NUM> in communication with one UE <NUM>, in additional or alternative examples, the base station <NUM> may be in communication with any suitable quantity of UEs <NUM> and/or base stations <NUM>, and/or the UE <NUM> may be in communication with any suitable quantity of base stations <NUM> and/or UEs <NUM>. Furthermore, while the wireless communication <NUM> includes a channel state feedback procedure between the base station <NUM> and the UE <NUM>, it should be appreciated that in other examples, the wireless communication <NUM> may include additional or alternative feedback procedures.

In the illustrated example, the UE <NUM> may receive a first CSI-RS <NUM> from the base station <NUM>. In some examples, the UE <NUM> may measure various radio channel conditions and report the measurements to the base station <NUM> in response to receiving the first CSI-RS <NUM> (e.g., may perform the channel state feedback procedure). For example, after receiving the first CSI-RS <NUM>, the UE <NUM> may determine, at <NUM>, a first PMI based on a first wideband component W<NUM> and a first subband component W<NUM>. In some examples, the UE <NUM> may select the first wideband component W<NUM> from a wideband component codebook. In some examples, the UE <NUM> may utilize Equation <NUM> (above) to determine the first wideband component W<NUM>. The UE <NUM> may then generate and transmit a first CSI report <NUM> including, for example, the first PMI, channel quality information (CQI), and/or a rank indicator (RI).

The UE <NUM> may then receive a second CSI-RS <NUM> from the base station <NUM>. The UE <NUM> may then determine a second PMI in response to the second CSI-RS <NUM>. To determine the second PMI, the UE <NUM> may determine, at <NUM>, a second wideband component W<NUM>. In the illustrated example of <FIG>, the UE <NUM> may determine the second wideband component W<NUM> based on a determining of whether to reuse the first wideband component W<NUM> from the first PMI for the second wideband component W<NUM>.

For example, the UE <NUM> may determine whether to reuse the first wideband component W<NUM> from the first PMI or to determine the second wideband component W<NUM> independently of the first wideband component W<NUM> (e.g., select a new wideband component W<NUM> from a wideband component codebook or dictionary). In some examples, the UE <NUM> may determine, at <NUM>, the second wideband component W<NUM> from a subset of the wideband component codebook. In some examples, the UE <NUM> may determine, at <NUM>, the second wideband component W<NUM> based on properties associated with the first CSI-RS <NUM>, the second CSI-RS <NUM>, the first wideband component W<NUM>, and/or the UE <NUM>.

The UE <NUM> may then determine, at <NUM>, a second subband component W<NUM>. In some examples, the UE <NUM> may determine the second subband component W<NUM> based on the second CSI-RS <NUM> and the second wideband component W<NUM>.

After determining the second wideband component W<NUM> and the second subband component W<NUM>, the UE <NUM> may determine, at <NUM>, a second PMI based on the second wideband component W<NUM> and the second subband component W<NUM>. For example, the UE <NUM> may utilize Equation <NUM> (above) to determine the second PMI. The UE <NUM> may then generate and transmit a second CSI report <NUM> including the second PMI to the base station <NUM>.

As described above, in some examples, the determining, at <NUM>, of the second wideband component W<NUM> may include the UE <NUM> determining whether to update the wideband component W<NUM> (e.g., select a new wideband component W<NUM>) or to reuse a previous wideband component W<NUM> (e.g., the first wideband component W<NUM>). In some examples, when updating the wideband component W<NUM> for the second wideband component W<NUM>, the UE <NUM> may use the full codebook for selecting the second wideband component W<NUM>, while in other examples, the UE <NUM> may use a subset of the codebook for selecting the second wideband component W<NUM>. As described above, the UE <NUM> may compare one or more properties relating to the first CSI-RS <NUM>, the second CSI-RS <NUM>, the UE, and/or the first PMI when determining whether to update the wideband component W<NUM> for the second wideband component W<NUM> or to reuse the previous wideband component W<NUM> (e.g., the first wideband component W<NUM>).

In some examples, when determining, at <NUM>, the second wideband component W<NUM>, the UE <NUM> may compare properties of the current CSI-RS (e.g., the second CSI-RS <NUM>) to properties of a previous CSI-RS (e.g., the first CSI-RS <NUM>). For example, in some examples, the UE <NUM> may compare an identifier (ID) of the current CSI-RS <NUM> to an identifier of the previous CSI-RS <NUM>. By comparing the identifier of the current CSI-RS <NUM> to the identifier of the previous CSI-RS <NUM>, the UE <NUM> may be able to confirm that a previous CSI-RS has been received and that a previous wideband component W<NUM> has been selected (e.g., confirm that there is a previous wideband component W<NUM> to reuse for the second wideband component W<NUM>). In some examples, the UE <NUM> may compare the TCI state of the current CSI-RS <NUM> to the TCI state of the previous CSI-RS <NUM>. In some examples, the UE <NUM> may compare the beam configuration of the current CSI-RS <NUM> to the beam configuration of the previous CSI-RS <NUM>. In some examples, if the UE <NUM> determines that one or more properties between the current CSI-RS <NUM> and the previous CSI-RS <NUM> do not match, then the UE <NUM> may determine to update the wideband component W<NUM>. In certain such examples, if the UE <NUM> determines that the properties between the current CSI-RS <NUM> and the previous CSI-RS <NUM> do match, then the UE <NUM> may determine to reuse the previous wideband component W<NUM> (e.g., the first wideband component W<NUM>).

In some examples, when determining, at <NUM>, the second wideband component W<NUM>, the UE <NUM> may compare a quality of the determination of the last PMI update to a threshold quality. For example, the UE <NUM> may determine the quality of the determination of the first PMI update transmitted in the first CSI report <NUM> based the quantity of slots used when the determination of the first PMI was made. For example, in NR, there are uplink slots, downlink slots, and flexible slots that may be used, for example, when switching transmission directions (e.g., from a downlink transmission to an uplink transmission or from an uplink transmission to a downlink transmission). In certain such examples, if a flexible slot is used when determining the PMI, then the quality of the determination may not be relatively good. Thus, in certain examples, if the quantity of slots is less than a threshold quantity, the accuracy of the PMI selection may be reduced. Accordingly, if the UE <NUM> determines that the quality of the determination of the last PMI update (e.g., the first PMI of the illustrated example of <FIG>) does not satisfy the threshold quality, then the UE <NUM> may determine to update the wideband component W<NUM> for the determining of the second wideband component W<NUM>. In certain such examples, if the UE <NUM> determines that the quality of the determination of the last PMI update (e.g., the first PMI of the illustrated example of <FIG>) does satisfy the threshold quality, then the UE <NUM> may determine to reuse the previous wideband component W<NUM> (e.g., the first wideband component W<NUM>).

In some examples, when determining, at <NUM>, the second wideband component W<NUM>, the UE <NUM> may compare a quantity of reuses of the previous wideband component W<NUM> to a threshold number of consecutive slots (e.g., twenty slots). For example, while reusing a previous wideband component W<NUM> may be beneficial, it may also be beneficial to update the wideband component W<NUM> at certain intervals. In some examples, when determining whether to update the wideband component W<NUM> to use for the second wideband component W<NUM> or to reuse the previous wideband component W<NUM> (e.g., the first wideband component W<NUM>), the UE <NUM> may compare the number of times that the previous wideband component W<NUM> (e.g., the first wideband component W<NUM>) has been reused to a threshold number of consecutive slots. In certain such examples, the UE <NUM> may determine to reuse the previous wideband component W<NUM> when the number of times of reuse is less than (or equal to) the threshold number of consecutive slots, and the UE <NUM> may determine to update the wideband component W<NUM> for the determining of the second wideband component W<NUM> when the number of times of reuse is greater than the threshold number of consecutive slots.

In some examples, the quantity of the threshold number of consecutive slots may vary based on, for example, the frequency band. For example, for millimeter wave (mmWave or mmW) frequency bands, the UE <NUM> may use a first threshold number (e.g., <NUM> slots), while for subband frequency bands, the UE <NUM> may use a second threshold number (e.g., <NUM> slots).

In some examples, when determining, at <NUM>, the second wideband component W<NUM>, the UE <NUM> may compare a mobility of the UE to a mobility threshold and/or a channel condition to a channel condition threshold. For example, when the UE <NUM> is a low mobility device and has relatively good channel conditions, the UE <NUM> may determine to skip updating the wideband component W<NUM> and to reuse the previous wideband component W<NUM> (e.g., the first wideband component W<NUM>). In certain such examples, whether the UE <NUM> is a low mobility device may be based on a comparison of mobility-related measurements to the mobility threshold. Similarly, whether the UE <NUM> has relatively good channel conditions may be based on a comparison of channel condition measurements to the channel condition threshold. As used herein, the channel condition refers to the channel condition of reference signals received at the UE. In some examples, the mobility-related measurements and/or the channel condition measurements (e.g., the channel condition of reference signals received at the UE) may include one or more of a Doppler shift, a Doppler spread, an average delay, a delay spread, and/or a spatial Rx parameter.

In some examples, the UE <NUM> may determine to reuse the previous wideband component W<NUM> (e.g., the first wideband component W<NUM>) when the mobility of the UE (based on the mobility-related measurements) satisfies the mobility threshold and the channel condition (based on the channel condition measurements) satisfies the channel condition threshold, and the UE <NUM> may determine to update the wideband component W<NUM> for the determining of the second wideband component W<NUM> when the mobility of the UE does not satisfy the mobility threshold and/or the channel condition does not satisfy the channel condition threshold.

In some examples, the mobility of the UE and/or the channel conditions may be divided into different tiers. For example, based on different mobility-related measurements and/or channel condition measurements, the UE <NUM> may be classified as a high-mobility device, a medium-mobility device, or a low-mobility device. In certain such examples, the UE <NUM> may apply different thresholds for determining the mobility classification of the device. For example, the UE <NUM> may determine that the UE is (<NUM>) a low-mobility device when the mobility of the UE is less than a first mobility threshold and the channel condition is greater than a first channel condition threshold, (<NUM>) a medium-mobility device when the mobility of the UE is greater than or equal to the first mobility threshold and less than a second mobility threshold and the channel condition is less than or equal to the first channel condition threshold and greater than a second channel condition threshold, or (<NUM>) a high-mobility device when the mobility of the UE greater than or equal to the second mobility threshold and/or the channel condition is less or equal to the second channel condition threshold.

In certain such examples, when the UE <NUM> determines that the UE is a low-mobility device, then the UE <NUM> may skip updating the wideband component W<NUM> (e.g., may reuse the first wideband component W<NUM>). In some examples, when the UE <NUM> determines that the UE is a high-mobility device, then the UE <NUM> may update the wideband component W<NUM> by selecting a new wideband component W<NUM> from the wideband component codebook. In some examples, when the UE <NUM> determines that the UE is a medium-mobility device, then the UE <NUM> may update the wideband component W<NUM> by selecting the new wideband component W<NUM> from a subset of the wideband component codebook. By selecting the second wideband component W<NUM> from the subset of the wideband component codebook (rather than from the full wideband component codebook), the UE <NUM> is able to reduce the complexity of PMI selection while still performing relatively accurate PMI selection. In some examples, the UE <NUM> may determine the subset of the wideband component codebook based on, for example, DFT indices associated with angular directions and DFT beams. For example, the UE <NUM> may determine at time n (e.g., when determining to update the wideband component W<NUM>) that a DFT index <NUM> is the strongest beam. The UE <NUM> may then determine the subset of the wideband component codebook based on the determined DFT index <NUM> (e.g., the subset may include <NUM>, <NUM>, <NUM>, <NUM>, <NUM>}).

While the above-described example describes three example classifications for the UE (e.g., a low-mobility UE, a medium-mobility UE, and a high-mobility UE), it should be appreciated that in other examples, any suitable quantity of classifications may be used. In certain such examples, the different mobility thresholds, the different channel condition thresholds, and/or the different subsets of the wideband component codebook may vary based on the corresponding classifications for the UE.

It should be appreciated that in different examples, any quantity and/or combination of properties may be used for determining whether to update the wideband component W<NUM> and/or to reuse the previous wideband component W<NUM> (e.g., from the first PMI) for the second wideband component W<NUM>.

<FIG> is a flowchart <NUM> of a method of wireless communication. <FIG> is a flowchart <NUM> of another method of wireless communication. The methods <NUM> and/or <NUM> may be performed by a UE (e.g., the UE <NUM>, the UE <NUM>, the UE <NUM>, the apparatus <NUM>/<NUM>', and/or the processing system <NUM>, which may include the memory <NUM> and which may be the entire UE <NUM> or a component of the UE <NUM>, such as the TX processor <NUM>, the RX processor <NUM>, and/or the controller/processor <NUM>). Optional aspects are illustrated with a dashed line.

The flowchart <NUM> of <FIG> is a method of wireless communication that facilitates improving performance of channel state feedback via dynamically determining to update and/or skip precoder selection in the channel state feedback process and resulting in increased power/cycle savings.

At <NUM>, the UE may receive a first CSI-RS from a base station, as described in connection with, for example, the CSI-RS <NUM> of <FIG>. For example, a reception component <NUM> of apparatus <NUM> may facilitate the receiving of the first CSI-RS.

At <NUM>, the UE may determine a first PMI based on the first CSI-RS, a first wideband component W<NUM>, and a first subband component W<NUM>, as described in connection with, for example, the determining of the first PMI at <NUM> of <FIG>. For example, PMI determining component <NUM> may facilitate the determining of the first PMI.

At <NUM>, the UE may receive a second CSI-RS from the base station, as described in connection with, for example, the CSI-RS <NUM> of <FIG>. For example, the reception component <NUM> may facilitate the receiving of the second CSI-RS.

At <NUM>, the UE may select a second wideband component W<NUM> of a second PMI, as described in connection with, for example, the determining of the wideband component W<NUM> at <NUM> of <FIG>. For example, W<NUM> selection component <NUM> may facilitate the selecting of the second wideband component W<NUM>. In some examples, the UE may determine whether to reuse the first wideband component W<NUM> for the second wideband component W<NUM>, to select the second wideband component W<NUM> from a codebook (e.g., by determining the second wideband component W<NUM> independently of the first wideband component Wi), and/or to determine the second wideband component W<NUM> from a subset of the codebook.

In some examples, at <NUM>, the UE may determine whether to reuse the first wideband component W<NUM> of the first PMI for the second wideband component W<NUM>. For example, the W<NUM> selection component <NUM> may facilitate the determining of whether to reuse the first wideband component W<NUM>. In some examples, the UE may determine whether to reuse the first wideband component W<NUM> based on at least one of (<NUM>) whether an identifier (ID) of the second CSI-RS <NUM> is the same as an ID of the first CSI-RS <NUM>, (<NUM>) whether the first wideband component W<NUM> has been reused over a threshold number of consecutive slots, (<NUM>) whether a beam configuration of the second CSI-RS <NUM> is the same as a beam configuration of the first CSI-RS <NUM>, (<NUM>) whether a TCI state of the second CSI-RS <NUM> is the same as a TCI state of the first CSI-RS <NUM>, (<NUM>) whether a quality of the determination of the first PMI is greater than a threshold quality, or (<NUM>) whether a mobility of the UE is less than a first mobility threshold and a channel condition of reference signals received at the UE is greater than a first channel condition threshold.

For example, the UE may determine to reuse the first wideband component W<NUM> when one or more of the following conditions are satisfied: (<NUM>) the ID of the second CSI-RS <NUM> is the same as the ID of the first CSI-RS <NUM>, (<NUM>) the first wideband component W<NUM> has been reused less than the threshold number of consecutive slots, (<NUM>) the beam configuration of the second CSI-RS <NUM> is the same as the beam configuration of the first CSI-RS <NUM>, (<NUM>) the TCI state of the second CSI-RS <NUM> is the same as the TCI state of the first CSI-RS <NUM>, (<NUM>) the quality of the determination of the first PMI is greater than the threshold quality, and (<NUM>) the mobility of the UE is less than the first mobility threshold and the channel condition of the reference signals received at the UE is greater than the first channel condition threshold. Example techniques for determining whether to reuse the first wideband component W<NUM> are also described below in connection with the flowchart <NUM> of <FIG>.

At <NUM>, the UE may select a second subband component W<NUM> of the second PMI, as described in connection with the determining of the second subband component W<NUM> at <NUM> of <FIG>. For example, W<NUM> selection component <NUM> may facilitate the selecting of the second subband component W<NUM>.

At <NUM>, the UE may determine the second PMI based on the second CSI-RS <NUM>, the second wideband component W<NUM>, and the second subband component W<NUM>, as described in connection with the determining of the second PMI at <NUM> of <FIG>. For example, the PMI determining component <NUM> may facilitate the determining of the second PMI.

At <NUM>, the UE may report the second PMI to the base station, as described in connection with the transmitting of the second CSI report <NUM> of <FIG>. For example, transmission component <NUM> may facilitate the reporting of the second PMI.

The flowchart <NUM> of <FIG> is a method of wireless communication that facilitates improving performance of channel state feedback via dynamically determining to update a precoder selection and/or to reuse a precoder selection in the channel state feedback process and resulting in increased power/cycle savings. In some examples, the flowchart <NUM> of <FIG> may be used to implement <NUM> of <FIG> to select the second wideband component W<NUM> and/or <NUM> to determine whether to reuse a first wideband component W<NUM>.

Although the example flowchart <NUM> includes a series of tests of different conditions, it should be appreciated that the selecting of the second wideband component W<NUM> and/or the determining of whether to reuse the first wideband component W<NUM> may be based on any suitable quantity of conditions. Furthermore, it should be appreciated that in additional or alternative examples, the ordering of the tests of the different conditions included in the flowchart <NUM> may be in any suitable order and/or may include any suitable subset of the tests of different conditions.

At <NUM>, the UE may determine whether an identifier of a second CSI-RS is the same as an identifier of a first CSI-RS. For example, ID handling component <NUM> apparatus <NUM> may facilitate the determining of the identifier of the second CSI-RS and/or the comparing of the identifier of the second CSI-RS to the identifier of the first CSI-RS. If, at <NUM>, the UE determined that the identifier of the second CSI-RS was not the same as the identifier of the first CSI-RS, then control proceeds to <NUM> to determine the second wideband component W<NUM> independently of the first wideband component W<NUM>.

If, at <NUM>, the UE determined that the identifier of the second CSI-RS was the same the identifier of the first CSI-RS, then, at <NUM>, the UE may determine whether the first wideband component W<NUM> has been reused less than a consecutive slots threshold. For example, reuse counting component <NUM> may facilitate the determining of the quantity of reuses of the first wideband component W<NUM> and/or the comparing of the quantity of reuses to the consecutive slots threshold. If, at <NUM>, the UE determined that the first wideband component W<NUM> has not been reused less than the consecutive slots threshold (e.g., the first wideband component W<NUM> was used a quantity that is the consecutive slots threshold), then control proceeds to <NUM> to determine the second wideband component W<NUM> independently of the first wideband component W<NUM>.

If, at <NUM>, the UE determined that the first wideband component W<NUM> has been reused less than the consecutive slots threshold, then, at <NUM>, the UE may determine whether a beam configuration of the second CSI-RS is the same as a beam configuration of the first CSI-RS. For example, beam configuration component <NUM> may facilitate the determining of the beam configuration of the second CSI-RS and/or the comparing of the beam configuration of the second CSI-RS to the beam configuration of the first CSI-RS. If, at <NUM>, the UE determined that the beam configuration of the second CSI-RS was not the same the beam configuration of the first CSI-RS, then control proceeds to <NUM> to determine the second wideband component W<NUM> independently of the first wideband component W<NUM>.

If, at <NUM>, the UE determined that the beam configuration of the second CSI-RS was the same as the beam configuration of the first CSI-RS, then, at <NUM>, the UE may determine whether a TCI state of the second CSI-RS is the same as a TCI state of the first CSI-RS. For example, TCI state component <NUM> may facilitate the determining of the TCI state of the second CSI-RS and/or the comparing of the TCI state of the second CSI-RS to the TCI state of the first CSI-RS. If, at <NUM>, the UE determined that the TCI state of the second CSI-RS was not the same as the TCI state of the first CSI-RS, then control proceeds to <NUM> to determine the second wideband component W<NUM> independently of the first wideband component W<NUM>.

If, at <NUM>, the UE determined that the TCI state of the second CSI-RS was the same as the TCI state of the first CSI-RS, then, at <NUM>, the UE may determine whether a quality of a determination of the first PMI is greater than a threshold quality. For example, PMI quality component <NUM> may facilitate the determining of the quality of the determination of the first PMI and/or the comparing of the quality of the determination to the threshold quality. If, at <NUM>, the UE determined that the quality of the determination of the first PMI did not satisfy the threshold quality (e.g., was less than or equal to the threshold quality), then control proceeds to <NUM> to determine the second wideband component W<NUM> independently of the first wideband component W<NUM>.

If, at <NUM>, the UE determined that the quality of the determination of the first PMI satisfied the threshold quality, then, at <NUM>, the UE may determine whether a mobility of the UE is less than a first mobility threshold and a channel condition of reference signals received at the UE is greater than a first channel condition threshold. For example, mobility component <NUM> may facilitate the determining of the mobility of the UE and/or the comparing of the mobility to the first mobility threshold, and channel condition component <NUM> may facilitate the determining of the channel condition of the reference signals received at the UE and/or the comparing of the channel condition to the first channel condition threshold. If, at <NUM>, the UE determined that the mobility of the UE satisfied the first mobility threshold and the channel condition of the reference signals received at the UE satisfied the first channel condition threshold, then control proceeds to <NUM> to facilitate reusing the first wideband component W<NUM> for the second wideband component W<NUM>.

If, at <NUM>, the UE determined that the mobility of the UE did not satisfy the first mobility threshold (e.g., the mobility of the UE was greater than or equal to the first mobility threshold) and/or the UE determined that the channel condition of reference signals received at the UE did not satisfy the first channel condition threshold (e.g., the channel condition of reference signals received at the UE was less than or equal to the first channel condition threshold), then, at <NUM>, the UE may determine whether the mobility of the UE is greater than or equal to the first mobility threshold and less than a second mobility threshold and the UE may determine whether channel condition of reference signals received at the UE is less than or equal to the first channel condition threshold and greater than a second channel condition threshold. For example, the mobility component <NUM> may facilitate the determining of the mobility of the UE and/or the comparing of the mobility of the UE to the first mobility threshold and the second mobility threshold, and the channel condition component <NUM> may facilitate the determining of the channel condition and/or the comparing of the channel condition to the first channel condition threshold and the second channel condition threshold.

If, at <NUM>, the UE determined that the mobility of the UE did not satisfy the second mobility threshold (e.g., the mobility of the UE was greater than or equal to the second threshold) and/or the UE determined that the channel condition of reference signals received at the UE did not satisfy the second channel condition threshold (e.g., the channel condition of reference signals was less than or equal to the second channel condition threshold), then control proceeds to <NUM> to determine the second wideband component W<NUM> independently of the first wideband component W<NUM>.

If, at <NUM>, the UE determined that the mobility of the UE satisfied the second mobility threshold (e.g., the mobility of the UE was greater than or equal to the first mobility threshold and less than the second mobility threshold) and that the channel condition of reference signals received at the UE satisfied the second channel condition threshold (e.g., the channel condition of reference signals was less than or equal to the first channel condition threshold and greater than the second channel condition threshold), then control proceeds to <NUM> to determine the second wideband component W<NUM> from a subset of a codebook.

At <NUM>, the UE may determine the second wideband component W<NUM> independently of the first wideband component W<NUM>. For example, W<NUM> selection component <NUM> may facilitate the determining of the second wideband component W<NUM> independently of the first wideband component W<NUM>. In some examples, the UE may determine the second wideband component W<NUM> independently of the first wideband component W<NUM> by selecting the second wideband component W<NUM> from a wideband component codebook.

At <NUM>, the UE may determine the second wideband component W<NUM> by selecting the second wideband component W<NUM> from a subset of the wideband component codebook. For example, the W<NUM> selection component <NUM> may facilitate the selecting of the second wideband component W<NUM> from the subset of the wideband component codebook.

At <NUM>, the UE may reuse the first wideband component W<NUM> for the second wideband component W<NUM>. For example, the W<NUM> selection component <NUM> may facilitate the selecting of the first wideband component W<NUM> for the second wideband component W<NUM>. In some examples, the UE may update the quantity of reuses of the first wideband component W<NUM> based on the reusing of the first wideband component W<NUM> for the second wideband component W<NUM>.

<FIG> is a conceptual data flow diagram <NUM> illustrating the data flow between different means/components in an example apparatus <NUM> in communication with a base station <NUM>. The apparatus <NUM> may be a UE. The apparatus <NUM> may perform the methods of flowcharts <NUM> and/or <NUM>. The apparatus <NUM> includes a reception component <NUM>, a W<NUM> selection component <NUM>, an ID handling component <NUM>, a reuse counting component <NUM>, a beam configuration component <NUM>, a TCI state component <NUM>, a PMI quality component <NUM>, a mobility component <NUM>, a channel condition component <NUM>, a W<NUM> selection component <NUM>, a PMI determining component <NUM>, and a transmission component <NUM>. The base station <NUM> may include the same or similar components as shown with respect to the base station <NUM>/<NUM> of <FIG>, the base station <NUM> of <FIG>, and/or the base station <NUM> of <FIG>.

The reception component <NUM> may be configured to receive various types of signals/messages and/or other information from other devices, including, for example, the base station <NUM>. The messages/information may be received via the reception component <NUM> and provided to one or more components of the apparatus <NUM> for further processing and use in performing various operations. For example, the reception component <NUM> may be configured to receive signaling including, for example, a first CSI-RS and/or a second CSI-RS (e.g., as described in connection with <NUM> and/or <NUM>).

The W<NUM> selection component <NUM> may be configured to select a wideband component W<NUM> of a PMI (e.g., as described in connection with <NUM>). In some examples, the W<NUM> selection component <NUM> may select the wideband component W<NUM> based on, for example, a determination on whether to reuse a wideband component W<NUM> from a previous PMI (e.g., as described in connection with <NUM>), a determination to select the wideband component W<NUM> from a subset of a codebook (e.g., as described in connection with <NUM>), and/or a determination to select the wideband component W<NUM> from the codebook (e.g., as described in connection with <NUM>).

The ID handling component <NUM> may be configured to determine whether an ID of a second CSI-RS is the same as an ID of a first CSI-RS (e.g., as described in connection with <NUM>).

The reuse counting component <NUM> may be configured to determine whether a first wideband component W<NUM> has been reused over a threshold number of consecutive slots (e.g., as described in connection with <NUM>).

The beam configuration component <NUM> may be configured to determine whether a beam configuration of a second CSI-RS is the same as a beam configuration of a first CSI-RS (e.g., as described in connection with <NUM>).

The TCI state component <NUM> may be configured to determine whether a TCI state of a second CSI-RS is the same as a TCI state of a first CSI-RS (e.g., as described in connection with <NUM>).

The PMI quality component <NUM> may be configured to determine whether a quality of a determination of a first PMI is greater than a threshold quality (e.g., as described in connection with <NUM>).

The mobility component <NUM> may be configured to determine whether a mobility of the apparatus <NUM> is less than a first mobility threshold and/or to determine whether the mobility of the apparatus <NUM> is greater than or equal to the first mobility threshold and less than a second mobility threshold (e.g., as described in connection with <NUM> and/or <NUM>).

The channel condition component <NUM> may be configured to determine whether a channel condition of reference signals received at the apparatus <NUM> is greater than a first channel condition threshold and/or to determine whether the channel condition of reference signals received at the apparatus <NUM> is less than or equal to the first channel condition threshold and greater than a second channel condition threshold (e.g., as described in connection with <NUM> and/or <NUM>).

The W<NUM> selection component <NUM> may be configured to select a subband component W<NUM> based on a wideband component W<NUM> and a CSI-RS (e.g., as described in connection with <NUM>).

The PMI determining component <NUM> may be configured to determine a PMI based on a wideband component W<NUM> and a subband component W<NUM> (e.g., as described in connection with <NUM> and/or <NUM>).

The transmission component <NUM> may be configured to transmit various types of signals/messages and/or other information to other devices, including, for example, the base station <NUM>. For example, the transmission component <NUM> may be configured to transmit uplink communications, such as a CSI report and/or a PMI signal, to the base station <NUM> (e.g., as described in connection with <NUM>).

The apparatus may include additional components that perform each of the blocks of the algorithm in the aforementioned flowcharts of <FIG> and/or <NUM>. As such, each block in the aforementioned flowcharts of <FIG> and/or <NUM> may be performed by a component and the apparatus may include one or more of those components.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an apparatus <NUM>' employing a processing system <NUM>. The processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> links together various circuits including one or more processors and/or hardware components, represented by the processor <NUM>, the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and the computer-readable medium / memory <NUM>. The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system <NUM> may be coupled to a transceiver <NUM>. The transceiver <NUM> is coupled to one or more antennas <NUM>. The transceiver <NUM> provides a means for communicating with various other apparatus over a transmission medium. The transceiver <NUM> receives a signal from the one or more antennas <NUM>, extracts information from the received signal, and provides the extracted information to the processing system <NUM>, specifically the reception component <NUM>. In addition, the transceiver <NUM> receives information from the processing system <NUM>, specifically the transmission component <NUM>, and based on the received information, generates a signal to be applied to the one or more antennas <NUM>. The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium / memory <NUM>. The processor <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium / memory <NUM>. The software, when executed by the processor <NUM>, causes the processing system <NUM> to perform the various functions described supra for any particular apparatus. The computer-readable medium / memory <NUM> may also be used for storing data that is manipulated by the processor <NUM> when executing software. The processing system <NUM> further includes at least one of the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The components may be software components running in the processor <NUM>, resident/stored in the computer readable medium / memory <NUM>, one or more hardware components coupled to the processor <NUM>, or some combination thereof. The processing system <NUM> may be a component of the UE <NUM> and may include the memory <NUM> and/or at least one of the TX processor <NUM>, the RX processor <NUM>, and/or the controller/processor <NUM>. Alternatively, the processing system <NUM> may be the entire UE (e.g., see the UE <NUM> of <FIG>).

In one configuration, the apparatus <NUM>/<NUM>' for wireless communication includes means for selecting, at a UE, a second wideband component W<NUM> of a second PMI, the second PMI to include the second wideband component W<NUM> and a second subband component W<NUM>, and the means for selecting the second wideband component W<NUM> being based at least on a determining of whether to reuse for the second wideband component W<NUM> a first wideband component W<NUM> of a first PMI previously determined based on a received first CSI-RS, the first PMI to include a first wideband component W<NUM> and a first subband component W<NUM>, means for determining the second PMI based on a received second CSI-RS, the second wideband component W<NUM>, and the second subband component W<NUM>, and means for reporting the determined second PMI to a base station. In another configuration, the apparatus <NUM>/<NUM>' may include means for receiving, from the base station, the first CSI-RS, means for determining the first PMI based on the received first CSI-RS, and means for receiving, from the base station, the second CSI-RS. In another configuration, the apparatus <NUM>/<NUM>' may include means for determining whether to reuse the first wideband component W<NUM> for the second wideband component W<NUM> based on at least one of (<NUM>) whether an ID of the second CSI-RS is the same as an ID of the first CSI-RS, (<NUM>) whether the first wideband component W<NUM> has been reused over a threshold number of consecutive slots, (<NUM>) whether a beam configuration of the second CSI-RS is the same as a beam configuration of the first CSI-RS, (<NUM>) whether a TCI state of the second CSI-RS is the same as a TCI state of the first CSI-RS, (<NUM>) whether a quality of the determination of the first PMI is greater than a threshold quality, or (<NUM>) whether a mobility of the UE is less than a first mobility threshold and a channel condition of reference signals received at the UE is greater than a first channel condition threshold. In another configuration, the apparatus <NUM>/<NUM>' may include means for determining the second wideband component W<NUM> independently of the first wideband component W<NUM> when the ID of the second CSI-RS is different than the ID of the first CSI-RS. In another configuration, the apparatus <NUM>/<NUM>' may include means for determining the second wideband component W<NUM> independently of the first wideband component W<NUM> when the first wideband component W<NUM> has been reused the threshold number of consecutive slots. In another configuration, the apparatus <NUM>/<NUM>' may include means for determining the second wideband component W<NUM> independently of the first wideband component W<NUM> when the beam configuration of the second CSI-RS is different than the beam configuration of the first CSI-RS. In another configuration, the apparatus <NUM>/<NUM>' may include means for determining the second wideband component W<NUM> independently of the first wideband component W<NUM> when the TCI state of the second CSI-RS is different than the TCI state of the first CSI-RS. In another configuration, the apparatus <NUM>/<NUM>' may include means for determining the second wideband component W<NUM> independently of the first wideband component W<NUM> when the quality of the determination of the first PMI is less than or equal to the threshold quality. In another configuration, the apparatus <NUM>/<NUM>' may include means for determining the second wideband component W<NUM> independently of the first wideband component W<NUM> when the mobility of the UE is greater than or equal to the first mobility threshold or the channel condition of the reference signals received at the UE is less than or equal to the first channel condition threshold. In another configuration, the apparatus <NUM>/<NUM>' may include means for determining the second wideband component W<NUM> from a subset of a codebook when the mobility of the UE is less than a second mobility threshold but greater than or equal to the first mobility threshold and the channel condition of the reference signals received at the UE is greater than a second channel condition threshold but less than or equal to the first channel condition threshold, and means for determining the second wideband component W<NUM> from the codebook when the mobility of the UE is greater than the second mobility threshold or the channel condition of the reference signals received at the UE is less than the second channel condition threshold. In another configuration, the apparatus <NUM>/<NUM>' may include means for determining to reuse the first wideband component W<NUM> when one or more of the following conditions are satisfied: (<NUM>) the ID of the second CSI-RS is the same as the ID of the first CSI-RS, (<NUM>) the first wideband component W<NUM> has been reused less than the threshold number of consecutive slots, (<NUM>) the beam configuration of the second CSI-RS is the same as the beam configuration of the first CSI-RS, (<NUM>) the TCI state of the second CSI-RS is the same as the TCI state of the first CSI-RS, (<NUM>) the quality of the determination of the first PMI is greater than the threshold quality, and (<NUM>) the mobility of the UE is less than the first mobility threshold and the channel condition of the reference signals received at the UE is greater than the first channel condition threshold. In another configuration, the apparatus <NUM>/<NUM>' may include means for selecting the second subband component W<NUM> based on the second wideband component W<NUM> and the second CSI-RS. As described supra, the processing system <NUM> may include the TX Processor <NUM>, the RX Processor <NUM>, and/or the controller/processor <NUM>. As such, in one configuration, the aforementioned means may be the TX Processor <NUM>, the RX Processor <NUM>, and/or the controller/processor <NUM> configured to perform the functions recited by the aforementioned means.

Example techniques disclosed herein facilitate adaptive precoder updating for channel state feedback. For example, techniques disclosed herein facilitate determining whether to reuse a first wideband component W<NUM> of a first PMI for a second wideband component W<NUM>, whether to select the second wideband component W<NUM> from a wideband component codebook, and/or whether to select the second wideband component W<NUM> from a subset of the wideband component codebook. In some examples, the determining of whether to reuse the first wideband component W<NUM> for the second wideband component W<NUM> may be based on one or more conditions associated with a first CSI-RS associated with the first wideband component W<NUM> and a second CSI-RS. For example, the determining of whether to reuse the first wideband component W<NUM> may be based on identifiers associated with the first CSI-RS and the second CSI-RS, a quantity of reuses of the first wideband component W<NUM>, beam configurations of the first CSI-RS and the second CSI-RS, TCI states of the first CSI-RS and the second CSI-RS, a quality of the determination of the first PMI, a mobility of the UE, and/or a channel condition of reference signals received at the UE. By dynamically determining whether to reuse the first wideband component W<NUM>, techniques disclosed herein may increase power/cycle savings without introducing performance degradation.

Claim 1:
A method (<NUM>) of wireless communication of a user equipment, UE (<NUM>, <NUM>, <NUM>), comprising:
selecting (<NUM>) a second wideband component W<NUM> of a second precoding matrix indicator, PMI, the second PMI comprising the second wideband component W<NUM> and a second subband component W<NUM>,
wherein the selecting of the second wideband component W<NUM> is based at least on a determining of whether to reuse for the second wideband component W<NUM> a first wideband component of a first PMI previously determined (<NUM>) based on received first channel state information reference signals, CSI-RS, (<NUM>),
wherein the first PMI comprises a first wideband component and a first subband component, and
wherein the determining of whether to reuse the first wideband component for the second wideband component W<NUM> is based on whether properties of a second CSI-RS and the first CSI-RS are the same and whether a quality of the determination of the first PMI is greater than a threshold quality;
determining (<NUM>, <NUM>) the second PMI based on the received second CSI-RS (<NUM>), the second wideband component W<NUM>, and the second subband component W<NUM>; and
reporting (<NUM>, <NUM>) the determined second PMI to a base station (<NUM>).