Patent Description:
<CIT> discusses a method of feeding back, by a terminal, channel state information in a wireless communication system. <NPL>" discusses design aspects for DFT-based compression techniques. <CIT> discusses a method for transmitting channel quality information from a user equipment in a wireless communication system that supports coordinated multiple point (CoMP) transmission and reception.

In accordance with the present invention, there is provided a method of wireless communication carried out by a user equipment as set out in claim <NUM>, a method for wireless communication by a base station as set out in claim <NUM>, a user equipment for wireless communication as set out in claim <NUM>, and a base station for wireless communication as set out in claim <NUM>. Preferred embodiments can be found in the dependent claims.

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for channel quality indictor (CQI) reporting with precoding matrix indicator (PMI) frequency domain (FD) units. CQI is calculated based on PMI. In some cases, CQI and PMI have different FD unit sizes.

The following description provides examples of CQI reporting with PMI FD units, and is not limiting of the scope, applicability, or examples set forth in the claims.

The techniques described herein may be used for various wireless networks and radio technologies. While aspects may be described herein using terminology commonly associated with <NUM>, <NUM>, and/or <NUM> wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, including later technologies.

New radio (NR) access (e.g., <NUM> NR technology) may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., <NUM> or beyond), millimeter wave (mmW) targeting high carrier frequency (e.g., <NUM> or beyond), massive machine type communications MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra-reliable low-latency communications (URLLC). NR may support beamforming and beam direction may be dynamically configured.

For example, the wireless communication network <NUM> may be a New Radio (NR) or <NUM> network. As shown in <FIG>, the wireless communication network <NUM> may be in communication with a core network <NUM>. The core network <NUM> may be in communication with one or more base station (BSs) <NUM> and/or user equipment (UE) <NUM> in the wireless communication network <NUM> via one or more interfaces.

As illustrated in <FIG>, the wireless communication network <NUM> may include a number of BSs <NUM> and other network entities. In some examples, the BSs <NUM> may be interconnected to one another and/or to one or more other BS or network nodes (not shown) in wireless communication network <NUM> through various types of backhaul interfaces (e.g., a direct physical connection, a wireless connection, a virtual network, or the like) using any suitable transport network. A BS <NUM> may support one or multiple cells.

The BSs <NUM> may communicate with UEs <NUM> (e.g., 120x, 120y, etc.) which may be dispersed throughout the wireless communication network <NUM>. Each UE <NUM> may be stationary or mobile. Wireless communication network <NUM> may also include relay stations that receive a transmission of data and/or other information from an upstream station (e.g., a BS 110a or a UE 120r) and send a transmission of the data and/or other information to a downstream station (e.g., a UE <NUM> or a BS <NUM>) and/or that relays transmissions between UEs <NUM>.

The BSs <NUM> and UEs <NUM> may be configured for CQI reporting with PMI FD units. As shown in <FIG>, the UE 120a may include a CSI feedback manager <NUM>. The BS 110a may include a CSI feedback manager <NUM>. The CSI feedback manager <NUM> and/or the CSI feedback manager <NUM> may be configured for CQI reporting with PMI FD units in accordance with aspects of the disclosure.

<FIG> illustrates example components of BS 110a and UE 120a (as depicted in <FIG>), which may be used to implement aspects of the present disclosure. At the BS 110a, a transmit processor <NUM> may receive data from a data source <NUM> and control information from a controller/processor <NUM>. The processor <NUM> may also generate reference symbols, e.g., for the primary synchronization signal (PSS), secondary synchronization signal (SSS), and channel state information reference signal (CSI-RS). A transmit (TX) multiple-input multiple-output (MIMO) processor <NUM> may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) 232a through 232t. Downlink signals from modulators 232a through 232t may be transmitted via the antennas 234a through 234t, respectively.

At the UE 120a, the antennas 252a through 252r may receive the downlink signals from the BS 110a and may provide received signals to the demodulators (DEMODs) in transceivers 254a through 254r, respectively. A MIMO detector <NUM> may obtain received symbols from all the demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor <NUM> may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120a to a data sink <NUM>, and provide decoded control information to a controller/processor <NUM>.

On the uplink, at UE 120a, a transmit processor <NUM> may receive and process data (e.g., for the physical uplink shared channel (PUSCH)) from a data source <NUM> and control information (e.g., for the physical uplink control channel (PUCCH) from the controller/processor <NUM>. The symbols from the transmit processor <NUM> may be precoded by a TX MIMO processor <NUM> if applicable, further processed by the modulators in transceivers 254a through 254r (e.g., for SC-FDM, etc.), and transmitted to the BS 110a. At the BS 110a, the uplink signals from the UE 120a may be received by the antennas <NUM>, processed by the modulators <NUM>, detected by a MIMO detector <NUM> if applicable, and further processed by a receive processor <NUM> to obtain decoded data and control information sent by the UE 120a.

Antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the UE 120a and/or antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the BS 110a may be used to perform the various techniques and methods described herein for CQI reporting with PMI FD units. The controllers/processors <NUM> and <NUM> may direct the operation at the BS 110a and the UE 120a, respectively. The processor <NUM> and/or other processors and modules at the BS 110a may perform or direct the execution of processes for the techniques described herein. As shown in <FIG>, the controller/processor <NUM> of the UE 120a includes a CSI feedback manager <NUM>. The controller/processor <NUM> of the BS 110a includes a CSI feedback manager <NUM>. The CSI feedback manager <NUM> and/or the CSI feedback manager <NUM> may be configured for CQI reporting with PMI FD units in accordance with aspects of the disclosure.

NR may utilize orthogonal frequency division multiplexing (OFDM) on the uplink and/or downlink and single-carrier frequency division multiplexing (SC-FDM) on the downlink and/or uplink. OFDM and SC-FDM partition the system bandwidth into multiple orthogonal subcarriers, also referred to as tones, bins, etc. Each subcarrier may be modulated with data. For example, the base subcarrier spacing (SCS) may be <NUM> and other subcarrier spacing may be defined with respect to the base SCS, for example, <NUM>, <NUM>, <NUM>, <NUM>, etc. The minimum resource allocation (called a "resource block" (RB)) may be <NUM> consecutive subcarriers. The system bandwidth may also be partitioned into subbands covering multiple RBs.

Each subframe may include a variable number of slots depending on the SCS. Each slot may include a variable number of symbol periods (e.g., <NUM> or <NUM> symbols) depending on the SCS.

Channel state information (CSI) may refer to channel properties of a communication link. The CSI may represent the combined effects of, for example, scattering, fading, and power decay with distance between a transmitter and receiver. Channel estimation using pilots, such as CSI reference signals (CSI-RS), may be performed to determine these effects on the channel. CSI may be used to adapt transmissions based on the current channel conditions, which is useful for achieving reliable communication, in particular, with high data rates in multi-antenna systems. CSI is typically estimated at the receiver, quantized, and fed back to the transmitter.

The time and frequency resources that can be used by the UE to report CSI are controlled by the gNB. CSI may consist of Channel Quality Indicator (CQI), precoding matrix indicator (PMI), CSI-RS resource indicator (CRI), SS/PBCH Block Resource indicator (SSBRI), layer indicator (LI), rank indicator (RI) and/or L1-RSRP.

The network (e.g., a BS), may configure UEs for CSI reporting. For example, the BS configures the UE with a CSI report configuration or with multiple CSI report configurations. The CSI report configuration may be provided to the UE via higher layer signaling, such as radio resource control (RRC) signaling (e.g., CSI-ReportConfig). The CSI report configuration may be associated with CSI-RS resources for channel measurement (CM), interference measurement (IM), or both. The CSI report configuration configures CSI-RS resources for measurement (e.g., CSI-ResourceConfig). The CSI-RS resources provide the UE with the configuration of CSI-RS ports, or CSI-RS port groups, mapped to time and frequency resources (e.g., resource elements (REs)). CSI-RS resources can be zero power (ZP) or non-zero power (NZP) resources. At least one NZP CSI-RS resource may be configured for CM.

The CSI report configuration also configures the CSI parameters (sometimes referred to as quantities) to be reported. Three codebooks include Type I single panel, Type I multi-panel, and Type II single panel. Regardless which codebook is used, the CSI report may include the CQI, PMI, CRI, and/or RI. The structure of the PMI may vary based on the codebook. The CRI, RI, and CQI may be in a first part (Part I) and the PMI may be in a second part (Part II) of the CSI report. For the Type I single panel codebook, the PMI may consist of a W1 matrix (e.g., subest of beams) and a W2 matrix (e.g., phase for cross polarization combination and beam selection). For the Type I multi-panel codebook, compared to type I single panel codebook, the PMI further comprises a phase for cross panel combination. For the Type II single panel codebook, the PMI is a linear combination of beams; it has a subset of orthogonal beams to be used for linear combination and has per layer, per polarization, amplitude and phase for each beam. For the PMI of any type, there can be wideband (WB) PMI and/or subband (SB) PMI as configured.

The CSI report configuration may configure the UE for aperiodic, periodic, or semi-persistent CSI reporting. For periodic CSI, the UE may be configured with periodic CSI-RS resources. Periodic CSI and semi-persistent CSI report on physical uplink control channel (PUCCH) may be triggered via RRC or a medium access control (MAC) control element (CE). For aperiodic and semi-persistent CSI on the physical uplink shared channel (PUSCH), the BS may signal the UE a CSI report trigger indicating for the UE to send a CSI report for one or more CSI-RS resources, or configuring the CSI-RS report trigger state (e.g., CSI-AperiodicTriggerStateList and CSI-SemiPersistentOnPUSCH-TriggerStateList). The CSI report trigger for aperiodic CSI and semi-persistent CSI on PUSCH may be provided via downlink control information (DCI). The CSI-RS trigger may be signaling indicating to the UE that CSI-RS will be transmitted for the CSI-RS resource.

The UE may report the CSI feedback based on the CSI report configuration and the CSI report trigger. For example, the UE may measure the channel associated with CSI for the triggered CSI-RS resources. Based on the measurements, the UE may select a preferred CSI-RS resource. The UE reports the CSI feedback for the selected CSI-RS resource. LI may be calculated conditioned on the reported CQI, PMI, RI and CRI; CQI may be calculated conditioned on the reported PMI, RI and CRI; PMI may be calculated conditioned on the reported RI and CRI; and RI may be calculated conditioned on the reported CRI.

As discussed above, a UE may be configured for CSI reporting, for example, by receiving a CSI configuration. In certain system (e.g., Release <NUM><NUM> NR), the UE may be configured to report at least a Type II precoder across configured frequency domain (FD) units: <MAT> where bi is the selected beam, ci is the set of linear combination coefficients, L is the number of selected spatial beams, and N<NUM> corresponds to the number of frequency units (e.g., subbands, resource blocks (RBs), etc.). In certain systems (e.g., Rel-<NUM><NUM> NR), the UE may be configured to report compressed precoder feedback: <MAT> where the discrete Fourier transform (DFT) compression basis is given by: <MAT> where Mi is dimension of the compressed domain. The coefficients are given by: <MAT> and the dimension of the compressed domain is Mi < N<NUM>.

Each CSI report configuration may be associated with a single downlink bandwidth part (BWP). The CSI report setting configuration may define a CSI reporting band as a subset of subbands of the BWP. The associated DL BWP may indicated by a higher layer parameter (e.g., bwp-Id) in the CSI report configuration for channel measurement and contains parameter(s) for one CSI reporting band, such as codebook configuration, time-domain behavior, frequency granularity for CSI, measurement restriction configurations, and the CSI-related quantities to be reported by the UE. Each CSI resource setting may be located in the DL BWP identified by the higher layer parameter, and all CSI resource settings may be linked to a CSI report setting have the same DL BWP.

The UE may further receive an indication of the subbands for which the CSI feedback is requested. <FIG> shows example subbands configured for CSI reporting, in accordance with certain aspects of the present disclosure. In the example shown in <FIG>, <FIG> of the <NUM> total subbands are requested for CSI reporting. In some examples, a subband mask is configured for the requested subbands for CSI reporting (subbands <NUM>-<NUM>). The UE computes precoders for each requested subband and finds the PMI that matches the computed precoder on each of the subbands.

In certain systems (e.g., Rel-<NUM><NUM> NR) for CSI reporting, the UE can be configured via higher layer signaling (e.g., in the CSI report configuration) with one out of two possible subband sizes (e.g., reportFreqConfiguration contained in a CSI-ReportConfig) which indicates a frequency granularity of the CSI report, where a subband may be defined as <MAT> contiguous physical resource blocks (PRBs) and depends on the total number of PRBs in the bandwidth part, for example, as shown in the table <NUM> illustrated in <FIG>. As shown in the table <NUM>, in such systems, the maximum number of subbands may be <NUM> subbands.

In certain systems (e.g., Rel-<NUM> and beyond), a finer granularity can be used for CSI. For example, a subband size for PMI may be smaller than the subband sizes shown in <FIG>. The finer CSI granularity may lead to much larger CSI computation complexity than larger CSI granularity.

According to certain aspects, the UE may be configured to report PMI. As discussed above, the CSI configuration may be associated with a BWP, and the BWP may be associated with a bandwidth size and subband size. According to certain aspects, the CSI granularity (e.g., the PMI) spans X RBs. As discussed above, the frequency division (FD) unit size may be a fine granularity. For example, the subband size may be smaller than the subband sizes shown in <FIG>. In some examples, granularity may be as small as <NUM> RB or {<NUM>,<NUM>} configured by higher-layers. In some examples, the PMI granularity may be smaller than a CQI granularity. For example, X = (CQI subband size)/R, where R><NUM> is a predefined integer. Thus, the number of FD units (e.g., the number of subbands) may be up to the total number of configured subbands * R (e.g., 19R).

In some cases, to enhance compression performance for the compressed CSI feedback, the CSI reporting band may divided into segments (e.g., into two segments). <FIG> is a table <NUM> illustrating examples of resource band segmentation for CSI reporting and <FIG> illustrates an example segmentation of FD units for CSI reporting. Frequency domain compression may be performed separately for each of the segments. As shown in <FIG> and <FIG>, the segments may overlap. Precoder (e.g., PMI) calculation may be performed separately for each segment and reported (e.g., the beam matrix, coefficient matrix, and basis selection).

Aspects of the present disclosure provide techniques for channel quality indicator (CQI) feedback reporting with precoder matrix indicator (PMI) frequency domain (FD) units (e.g., fine granularity PMI FD units).

<FIG>, <FIG>, <FIG>, and <FIG> are flow diagrams illustrating example operations <NUM>, <NUM>, <NUM>, and <NUM>, respectively, for wireless communication in accordance with certain aspects of the present disclosure. The operations <NUM>, <NUM>, <NUM>, and/or <NUM> may be performed, for example, by UE (e.g., such as a UE 120a in the wireless communication network <NUM>). Operations <NUM>, <NUM>, <NUM>, and/or <NUM> may be implemented as software components that are executed and run on one or more processors (e.g., processor <NUM> of <FIG>). Further, the transmission and reception of signals by the UE in operations <NUM>, <NUM>, <NUM>, and/or <NUM> may be enabled, for example, by one or more antennas (e.g., antennas <NUM> of <FIG>). In certain aspects, the transmission and/or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., processor <NUM>) obtaining and/or outputting signals.

According to certain aspects, as shown in <FIG>, PMI FD units segments may be overlapping. Aspects of the present disclosure provide techniques for calculating CSI, such as the CQI, for the overlapping parts of the segments. <FIG> is a flow diagram illustrating example operations <NUM> for calculating CQI for the overlapping segments, in accordance with certain aspects of the present disclosure.

The operations <NUM> may begin, at <NUM>, by receiving a CSI reporting configuration. The CSI includes CQI and PMI feedback. The CSI report may indicate or be associated with a BWP. The BWP may be associated with one or more FD unit sizes.

At <NUM>, the UE determines first and second segments of FD units for the PMI feedback. The first and second segments partially overlap. The UE may also determine FD units (e.g., subbands) for reporting the CQI. The FD units for the PMI feedback have first a FD unit size smaller (e.g., less RBs in an FD unit) than a second FD unit size for the CQI (i.e., the PMI may have a finer granularity than the CQI). In some examples, the FD unit sizes for the CQI and/or the PMI are indicated in the CSI report configuration and/or associated with the BWP. In some examples, the UE receives an indication of the requested FD units for CQI and/or PMI reporting.

At <NUM>, the UE calculates the CQI for the overlapping FD units based on the PMI for at least a portion of the first and/or second overlapping segments. In some examples, the UE calculates the CQI based on the average CQI resulted by the PMIs for the corresponding FD units.

According to certain aspects, the UE calculates the CQI based on the PMI for the corresponding FD units in the segment starting with a lower FD unit index. In the example shown in <FIG>, the UE calculates the CQI for the overlapping FD units <NUM>-<NUM> based on the average of the PMIs obtained by the PMIs from the FD units <NUM>-<NUM> of the segmentation #<NUM>.

According to certain aspects, the UE calculates the CQI based on the PMI for the corresponding FD units in the segment starting with a higher FD unit index. In the example shown in <FIG>, the UE calculates the CQI for the overlapping FD units <NUM>-<NUM> based on the average of the PMIs obtained by the PMIs from the FD units <NUM>-<NUM> of the segmentation #<NUM>.

According to certain aspects, the UE calculates the CQI based on the PMI for the corresponding FD units in both of the segments. In the example shown in <FIG>, the UE calculates the CQI for the overlapping FD units <NUM>-<NUM> based on the average of the PMIs obtained by the PMIs from the FD units <NUM>-<NUM> of both the segmentation #<NUM> and the segmentation #<NUM>.

According to certain aspects, the UE calculates the CQI based on the PMI for the corresponding FD units in the segment having more FD units than the other segment. In the example shown in <FIG>, the segmentation #<NUM> and the segmentation #<NUM> have the same number of FD units (<NUM> FD units). However, the segmentation #<NUM> and the segmentation #<NUM> could have different numbers of FD units. In that case, the UE calculates the CQI for the overlapping FD units <NUM>-<NUM> based on the average of the PMIs obtained by the PMIs from the FD units <NUM>-<NUM> of the longer segment (i.e., having more FD units).

According to certain aspects, the UE calculates the CQI for a first portion of the overlapping FD units based on the PMI for the corresponding FD units in the segment starting with a lower FD index, and calculates the CQI for a second portion of the overlapping FD units based on the PMI for the corresponding FD units in the segment starting with a higher FD unit. The first portion and second portion of the overlapping FD units can be determined based at least in part on an association between the CQI reporting band configuration and PMI reporting band configuration. In the example shown in <FIG>, the UE calculates the CQI for the first portion of the overlapping FD units (e.g., FD units <NUM> or <NUM>-<NUM>) based on the average of the PMIs obtained by the PMIs from the corresponding FD units (e.g., FD units <NUM> or <NUM>-<NUM>) of the segmentation #<NUM>, having the lower starting FD unit index; and the UE calculates the CQI for the second portion of the overlapping FD units (e.g., FD units <NUM> or <NUM>-<NUM>) based on the average of the PMIs obtained by the PMIs from the corresponding FD units (e.g., FD units <NUM> or <NUM>-<NUM>) of the segmentation #<NUM>, having the higher starting FD unit index. The number of PMI FD units in the first and second portions are dependent on the relationship CQI SB grid and PMI FD unit grid. In the example shown in <FIG>, for the CQI subband configuration #<NUM>, the first portion includes FD units <NUM> and <NUM> (because they align with the CQI subband <NUM>) and the second portion includes FD unit <NUM> (because CQI subband <NUM> is only partially aligned with the overlapping PMI FD units); and for the CQI subband configuration #<NUM>, the first portion includes FD unit <NUM> (because CQI subband <NUM> is only partially aligned with the overlapping PMI FD units) and the second portion includes FD units <NUM> and <NUM> (because CQI subband <NUM> aligns with those PMI FD units).

According to certain aspects, as shown in <FIG>, PMI FD units segments may not be perfectly aligned with the CQI FD units. Aspects of the present disclosure provide techniques for calculating CSI, such as the CQI, based on the alignment. <FIG> is a flow diagram illustrating example operations <NUM> for calculating CQI based on the alignment of the CQI and PMI FD units, in accordance with certain aspects of the present disclosure.

At <NUM>, the UE determines a configured subband size for the CQI feedback and a number of FD units configured for the PMI feedback corresponding to the subband size for the CQI feedback. The FD units for the PMI feedback can have first a FD unit size smaller (e.g., less RBs in an FD unit) than the subband size for the CQI (i.e., the PMI may have a finer granularity than the CQI). In some examples, the configured subband size for the CQI and/or the PMI are indicated in the CSI report configuration and/or are associated with the configured BWP. In some examples, the UE receives an indication (e.g., one or more FD unit or subband masks) of the requested FD units for CQI and/or PMI reporting. As discussed above, the configured subband size for the CQI feedback may be an integer multiple R of the FD unit size for the PMI feedback.

At <NUM>, the UE calculates the CQI feedback for CQI subbands based on at least a portion of the corresponding first number of FD units for the PMI feedback. The portion of the number of FD units is based on alignment of the CQI subbands and the numbers of FD units for the PMI feedback. In some examples, the UE calculates the CQI based on the average CQI resulted by the PMIs for the corresponding FD units.

In some cases, the CQI subband mask and the PMI FD units mask may be configured separately. In this case, a CQI subband can have a size smaller than the configured CQI subband size. In some examples, at least one of the CQI subbands may be aligned with R ' FD units, that is less than R FD units, of the first number of FD units for the PMI feedback. In the example shown in <FIG>, R is equal to <NUM>, in other words, the CQI subbands each correspond to two PMI FD units. As shown in <FIG>, for the CQI subband configuration #<NUM>, the CQI subband <NUM> is only aligned with <NUM> PMI FD unit (PMI FD unit <NUM>), thus, R' < R.

According to certain aspects, when the CQI subband size is smaller than the configured subband size, there may be only one PMI FD unit with the same size as the CQI subband. In some examples, when R' < R the UE calculates the CQI feedback for the at least one of the CQI subband based on the PMI for the R' aligned FD units. Thus, when there is only one PMI FD unit aligned with the CQI subband, only the one PMI FD unit may be used to calculate the CQI feedback. In the example shown in <FIG>, for the CQI subband <NUM>, the UE calculates the CQI based on the PMI resulting from PMI FD unit <NUM>.

According to certain aspects, when R' < R, for the last one FD unit, the UE applies the PMI of an aligned FD units for the PMI feedback to an adjacent FD unit not configured for PMI feedback, the adjacent FD unit being aligned with the at least one of the second number of FD units. The UE calculates the CQI feedback for the at least one of the second number of FD units based on the PMI for the aligned FD units. In the example shown in <FIG>, for the CQI subband <NUM>, the UE replicates the PMI resulting from the PMI FD unit <NUM> to the FD unit <NUM>, and the UE calculates the CQI based on averaging the estimate resulting from PMI FD unit <NUM>.

In some cases R' = <NUM>, when the at least one CQI subband does not align with any PMI FD units. According to certain aspects, when R' = <NUM>, for the least one CQI subband, the UE treats it as an error case and does not transmit CQI for the CQI subband. In the example shown in <FIG>, the CQI subbands in both of the illustrated CQI subband configuration #<NUM> and CQI subband configuration #<NUM> all have aligned PMI FD unit(s). However, in some cases for example the CQI subband <NUM> (not shown) in the CQI subband configuration #<NUM> does not align with any PMI FD units. The UE treats it as an error case and does not transmit any CQI for the CQI FD unit <NUM>.

In some cases, at least one PMI FD unit does not align with any CQI subbands. According to certain aspects, when the least one PMI FD unit does not align with any CQI subbands, the UE treats it as an error case and does not transmit PMI for the at least one FD unit. In the example shown in <FIG>, the PMI FD unit does not align with any CQI subbands (for both the CQI subband configuration #<NUM> and the CQI subband configuration #<NUM>). The UE treats it as an error case and does not transmit any PMI for the PMI FD unit <NUM>.

<FIG> is a flow diagram illustrating example operations <NUM> for wireless communication, in accordance with certain aspects of the present disclosure. The operations <NUM> may be performed, for example, by a BS (e.g., such as the BS 110a in the wireless communication network <NUM>). The operations <NUM> may be complimentary operations by the BS to the operations <NUM> performed by the UE. Operations <NUM> may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor <NUM> of <FIG>). Further, the transmission and reception of signals by the BS in operations <NUM> may be enabled, for example, by one or more antennas (e.g., antennas <NUM> of <FIG>). In certain aspects, the transmission and/or reception of signals by the BS may be implemented via a bus interface of one or more processors (e.g., controller/processor <NUM>) obtaining and/or outputting signals.

The operations <NUM> may begin, at <NUM>, by configuring a UE with a CSI reporting configuration. The CSI including CQI and PMI feedback. At <NUM>, the BS determines a configured subband size for the CQI feedback and a number of FD units configured for the PMI feedback corresponding to the subband size for the CQI feedback. At <NUM>, the BS receives a CSI report from the UE and, at <NUM>, the BS determines the FD units associated with the CQI feedback based on alignment of the CQI subbands and the number of FD units for the PMI feedback. For example, the BS may determine the CQI feedback applies to R or R' FD units based on a rule.

<FIG> is a flow diagram illustrating example operations <NUM> for configuring the PMI and CQI reporting bands, in accordance with certain aspects of the present disclosure.

At <NUM>, the UE determines a first number of FD units for the PMI feedback and a second number of FD units for the CQI feedback based on separate bitmaps for the PMI and CQI feedback, based on one bitmap and a ratio of FD unit sizes for the PMI and CQI feedback, or based on one bitmap for the PMI feedback. The FD units for the PMI feedback have first a FD unit size smaller (e.g., less RBs in an FD unit) than a second FD unit size for the CQI (i.e., the PMI may have a finer granularity than the CQI). In some examples, the FD unit sizes for the CQI and/or the PMI are indicated in the CSI report configuration and/or associated with the BWP. In some examples, the second FD unit size for the CQI feedback is an integer multiple R of the first FD unit size for the PMI feedback.

According to certain aspects, the UE receives separate bitmaps for the PMI and CQI feedback. R is the ratio of the length of the bitmap for PMI feedback to the length of the bitmap for CQI feedback. Each bit in the bitmap for the CQI feedback is associated with R bits in the bitmap for the PMI feedback, indicating that a configured CQI FD unit is associated with R' PMI FD units, where R' is the number of "<NUM>" in the R bits.

According to certain aspects, the UE receives a bitmap for the CQI feedback and an indication of R. For example, the UE may receive a parameter (numberOfPMISubbandsPerCQISubband) indicating the value of R (e.g., a value of <NUM> or <NUM>). The UE determines the second FD unit size for the CQI feedback is an integer multiple R first FD unit size for the PMI feedback. The UE determines the CQI for a CQI FD unit is associated with R PMI FD units. Based on the bitmap for the CQI feedback and the indication of R, the UE can determine the PMI FD units.

According to certain aspects, the UE receives a bitmap for the PMI feedback. The UE may determine the second FD unit size for the CQI feedback is an integer multiple R first FD unit size for the PMI feedback, where R is the ratio of the length of the bitmap for PMI feedback to the total number of CQI FD units in the BWP. The UE may determine that every R bits in the bitmap for PMI feedback indicates that R' FD units are associated with the CQI calculation for the corresponding CQI FD unit, where R' is the number of "<NUM>" in the R bits.

At <NUM>, the UE calculates the CQI feedback for the second number of FD units based on at least a portion of the corresponding first number of FD units for the PMI feedback. In some examples, the UE calculates the CQI based on the average CQI resulted by the PMIs for the corresponding FD units.

The operations <NUM> may begin, at <NUM>, by receiving a CSI reporting configuration. The CSI includes CQI and PMI feedback. The CSI reporting configuration indicates a BWP associated with a plurality of FD units.

At <NUM>, the UE determines a first number of FD units for the PMI feedback and a second number of FD units for the CQI feedback.

According to certain aspects, a starting FD unit index for the first and/or the second number of FD units starts from a lowest index of the BWP. In some examples, the first and/or second number of FD units starts from a lowest index of the system bandwidth. In some examples, one of the PMI or CQI FD units starts from the lowest FD unit index of the system bandwidth and the other one of the PMI or CQI FD units starts from the lowest FD unit index within the BWP.

At <NUM>, the UE calculates the CQI feedback for the determined second number of FD units based on at least a portion of the corresponding first number of FD units for the PMI feedback.

According to certain aspects, the UE may receive a CSI reporting configuration, the CSI including CQI and PMI feedback. The UE determines a first number of FD units for the PMI feedback and a second number of FD units for the CQI feedback. For CQI FD units associated with a number of PMI FD units R' that is less than a number of PMI FD units R, the UE pads one or more of the PMI FD units until R' is equal to R. The UE calculates the CQI feedback for the determined second number of FD units based on at least a portion of the corresponding first number of FD units for the PMI feedback.

The first number of FD units for the PMI feedback may have a first FD unit size smaller than a second FD unit size for the CQI. The second FD unit size for the CQI feedback may be an integer multiple R of the first FD unit size for the PMI feedback. At least one of the second number of FD units for the CQI feedback may be aligned with R' FD units less than R FD units of the first number of FD units for the PMI feedback.

<FIG> illustrates a communications device <NUM> that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in <FIG>, <FIG>, <FIG>, and/or <NUM>.

The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM> via a bus <NUM>. In certain aspects, the computer-readable medium/memory <NUM> is configured to store instructions (e.g., computer-executable code) that when executed by the processor <NUM>, cause the processor <NUM> to perform the operations illustrated in <FIG>, <FIG>, <FIG>, and/or <NUM>, or other operations for performing the various techniques discussed herein for CQI reporting for PMI FD units. In certain aspects, computer-readable medium/memory <NUM> stores code <NUM> for receiving a CSI report configuration in accordance with aspects of the present disclosure; code <NUM> for determining CQI and PMI FD units, in accordance with aspects of the present disclosure,; and code <NUM> for calculating CQI for the CQI FD units based on PMI, in accordance with aspects of the present disclosure. In certain aspects, the processor <NUM> has circuitry configured to implement the code stored in the computer-readable medium/memory <NUM>. The processor <NUM> includes circuitry <NUM> for receiving a CSI report configuration in accordance with aspects of the present disclosure; circuitry <NUM> for determining CQI and PMI FD units, in accordance with aspects of the present disclosure; and circuitry <NUM> for calculating CQI for the CQI FD units based on PMI, in accordance with aspects of the present disclosure.

Claim 1:
A method for wireless communication performed by a user equipment, UE, comprising:
receiving (<NUM>) a channel state information, CSI, reporting configuration from a base station, the CSI including channel quality information, CQI, and precoder matrix indicator, PMI, feedback;
determining (<NUM>) a configured subband size for the CQI feedback and a number of frequency domain, FD, units configured for the PMI feedback corresponding to the subband size for the CQI feedback, wherein the configured subband size for the CQI feedback is an integer multiple R of an FD unit size for the PMI feedback; and
calculating (<NUM>) the CQI feedback for CQI subbands based on at least a portion of the corresponding number of FD units for the PMI feedback, the portion of the number of FD units being based on alignment of the CQI subbands and the number of FD units for the PMI feedback, and transmitting a CSI report to the base station containing the calculated CQI feedback, the method characterized in that:
at least one of the CQI subbands is aligned with R' FD units less than R FD units of the number of FD units for the PMI feedback.