Patent Description:
<CIT> relates to a method for transmitting, by a user equipment (UE), a CSI (Channel State Information) report in a wireless communication system. More specifically, the method includes: receiving, from a base station, downlink control information (DCI) including information for triggering the CSI report; computing CSI based on the number of symbols related to a time for computing the CSI; and transmitting the CSI report to the base station, in which the number of symbols related to the time for computing the CSI is defined based on information for the number of antenna ports, information for a CSI-RS resource, information for a bandwidth granularity, and information for a CSI codebook type.

<CIT> relates to a CSI reporting method by a terminal in a wireless communication system which can comprise the steps of: receiving, from a base station, CSI configuration information for CSI reporting; and reporting, to the base station, CSI generated on the basis of the CSI configuration information. If the CSI comprises CQI and defined is a CQI table in which different CQI indexes are allocated by different MCS levels for the CQI reporting, the CSI configuration information comprises a CQI index range reportable by the terminal in the CQI table and/or CQI configuration information relating to the interval between the CQI indexes reportable by the terminal in the CQI index range.

Preferred embodiments of the invention are stipulated in the dependent claims. While several embodiments and/or examples have been disclosed in the description, the subject matter for which protection is sought is limited to those examples and/or embodiments which are encompassed by the scope of the appended claims. Embodiments and/or examples that do not fall under the scope of the claims are useful for understanding the invention.

After considering this discussion, and particularly after reading the section entitled "Detailed Description" one will understand how the features of this disclosure provide advantages that include improved CSI reporting configurations based on UE capabilities.

Certain aspects provide a method for wireless communication that may be performed by a user equipment (UE). The method generally includes receiving a channel state information (CSI) reporting configuration comprising one or more CSI reporting settings. Each CSI reporting setting is associated with one or more subbands for CSI. Each subband for CSI includes a frequency domain (FD) unit for channel quality information (CQI) feedback and one or more FD units for precoding matrix indicator (PMI) feedback. The method also includes determining, for each of the CSI reporting settings, at least one of an amount of CSI reference signal (CSI-RS) resources occupation or an amount of CSI-RS ports occupation, based at least in part on (i) a number of the FD units for PMI feedback within a single FD unit for CQI feedback or (ii) a number of FD units for PMI feedback within all of the subbands for CSI.

Certain aspects provide a method for wireless communication that may be performed by a network entity, such as a base station. The method generally includes determining one or more channel state information (CSI) reporting settings for a user equipment (UE). Each CSI reporting setting is associated with one or more subbands for CSI. Each subband for CSI includes a frequency domain (FD) unit for channel quality information (CQI) feedback and one or more FD units for precoding matrix indicator (PMI) feedback. The method also includes determining, for each of the CSI reporting settings, at least one of an amount of CSI reference signal (CSI-RS) resources occupation or an amount of CSI-RS ports occupation, based at least in part on (i) a number of the FD units for PMI feedback within a single FD unit for CQI feedback or (ii) a number of FD units for PMI feedback within all of the subbands for CSI.

Aspects of the present disclosure provide means for, apparatus, processors, and computer-readable mediums for performing the methods described herein.

Aspects of the present disclosure provide means for, apparatus, processors, and computer-readable mediums for performing techniques and methods that may be complementary to the operations by the UE described herein, for example, by a BS.

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for determining a CSI reporting configuration based on UE reported capabilities of the maximum amount of supported CSI reference signal (CSI-RS) resources and/or maximum amount of supported CSI-RS ports.

In some networks, wireless communications with a large number of antennas can be enabled with information obtained via CSI acquisition. One technique for acquiring CSI at the gNB in the downlink direction is via the UE calculating and reporting PMI for DL channel(s) based on CSI-RS transmitted by the gNB. However, one issue with this technique is that it may take a significant amount of UE memory to store channel estimation results and intermediate results of the CSI computation. To address this, some communication systems (e.g., Rel-<NUM> communication system) allow for CSI reporting configurations to be subject to UE capability. For example, these communication systems may allow for UE capability signaling of the maximum number of resources and/or ports supported by the UE, so that the gNB can trigger CSI report(s) subject to the reported capability of the UE.

However, later communication systems (e.g., Rel-<NUM> or later) may use a new Type II codebook that supports a finer PMI granularity (e.g., relative to Rel-<NUM> and earlier releases). This finer PMI granularity can cause the CSI computation to at least double in complexity. Accordingly, it may be desirable to provide improved techniques that enable the UE and/or gNB to determine the resource and ports occupation of each CSI report, such that the CSI reporting configuration is subject to the UE capabilities.

Aspects provide improved techniques for determining CSI-RS resources and CSI-RS ports occupation for finer PMI granularity. In particular, aspects provide a new rule for determining the CSI-RS resources and ports occupation when a particular type of codebook (e.g., Rel-<NUM> Type II codebook) is used for CSI reporting.

In one aspect, a UE may receive a CSI reporting configuration that includes one or more CSI reporting settings. Each CSI reporting setting may be associated with one or more subbands for CSI. Each subband for CSI may include a frequency domain (FD) unit for channel quality information (CQI) feedback and one or more FD units for precoding matrix indicator (PMI) feedback. The UE may determine, for each of the CSI reporting settings, at least one of an amount of CSI reference signal (CSI-RS) resources occupation or an amount of CSI-RS ports occupation, based at least in part on (i) a number of the FD units for PMI feedback within a single FD unit for CQI feedback or (ii) a number of FD units for PMI feedback within all of the subbands for CSI.

In some aspects, the UE may send (and the gNB may receive) an indication of a CSI processing capability of the UE. The CSI processing capability may include an indication of at least one of a number of CSI-RS resources supported by the UE or a number of CSI-RS ports supported by the UE. The UE and/or gNB may determine at least one of a total amount of CSI-RS resource occupation or a total amount of CSI-RS ports occupation based at least in part on the determined amount of CSI-RS resource occupation of each CSI reporting setting or the determined amount of CSI-RS ports occupation of each CSI reporting setting. The UE may perform CSI calculation and reporting of the one or more CSI reporting settings if at least one of the total amount of CSI-RS resource occupation is smaller than the indicated number of CSI-RS resources supported by the UE or the total amount of CSI-RS ports occupation is smaller than the indicated number of CSI-RS ports supported by the UE.

Doing so allows the UE and gNB to more efficiently determine CSI-RS resources/ports occupation (for certain types of codebooks), which in turn enables the BS to provide (and the UE to receive) CSI reporting configurations that are more efficiently tailored to the UE capabilities, relative to conventional techniques.

The following description provides examples of traffic burst awareness in communication systems, and is not limiting of the scope, applicability, or examples set forth in the claims.

As illustrated in <FIG>, the wireless communication network <NUM> may include a number of base stations (BSs) <NUM>10a-z (each also individually referred to herein as BS <NUM> or collectively as BSs <NUM>) and other network entities.

As illustrated, UE 120a includes a CSI reporting component <NUM>, which is configured to implement one or more techniques described herein for determining CSI-RS resources/ports occupation for CSI reporting. Using the CSI reporting component <NUM>, the UE 120a may receive a CSI reporting configuration that includes one or more CSI reporting settings. Each CSI reporting setting may be associated with one or more subbands for CSI. Each subband for CSI may include a FD unit for CQI feedback and one or more FD units for PMI feedback. The UE 120a may determine, for each of the CSI reporting settings, at least one of an amount of CSI-RS resources occupation or an amount of CSI-RS ports occupation, based at least in part on (i) a number of the FD units for PMI feedback within a single FD unit for CQI feedback or (ii) a number of FD units for PMI feedback within all of the subbands for CSI.

Using the CSI reporting component <NUM>, the UE 120a may send to a gNB (e.g., BS 110a) an indication of a CSI processing capability of the UE. The CSI processing capability may include an indication of at least one of a number of CSI-RS resources supported by the UE or a number of CSI-RS ports supported by the UE. The UE 120a may determine (e.g., using the CSI reporting component <NUM>) at least one of a total amount of CSI-RS resource occupation or a total amount of CSI-RS ports occupation based at least in part on the determined amount of CSI-RS resource occupation of each CSI reporting setting or the determined amount of CSI-RS ports occupation of each CSI reporting setting. The UE 120a may perform (e.g., using the CSI reporting component <NUM>) CSI calculation and reporting of the one or more CSI reporting settings if at least one of the total amount of CSI-RS resource occupation is smaller than the indicated number of CSI-RS resources supported by the UE or the total amount of CSI-RS ports occupation is smaller than the indicated number of CSI-RS ports supported by the UE.

As also illustrated, BS 110a (e.g., network entity or network node, such as a gNB) includes a CSI reporting component <NUM>, which is configured to implement one or more techniques described herein for determining CSI-RS resources/ports occupation in order to determine a CSI reporting configuration. Using the CSI reporting component <NUM>, the BS 110a may determine one or more CSI reporting settings for a UE (e.g., UE 120a). Each CSI reporting setting may be associated with one or more subbands for CSI. Each subband for CSI may include a FD unit for CQI feedback and one or more FD units for PMI feedback. The BS 110a may determine (e.g., via the CSI reporting component <NUM>), for each of the CSI reporting settings, at least one of an amount of CSI-RS resources occupation or an amount of CSI-RS ports occupation, based at least in part on (i) a number of the FD units for PMI feedback within a single FD unit for CQI feedback or (ii) a number of FD units for PMI feedback within all of the subbands for CSI.

Using the CSI reporting component <NUM>, the BS 110a may receive an indication of a CSI processing capability of the UE. The CSI processing capability may include an indication of at least one of a number of CSI-RS resources supported by the UE or a number of CSI-RS ports supported by the UE. The BS 110a may determine (e.g., with the CSI reporting component <NUM>) at least one of a total amount of CSI-RS resource occupation or a total amount of CSI-RS ports occupation based at least in part on the determined amount of CSI-RS resource occupation of each CSI reporting setting or the determined amount of CSI-RS ports occupation of each CSI reporting setting. The BS 110a may signal (e.g., via the CSI reporting component <NUM>) a CSI reporting configuration that includes the one or more CSI reporting settings to the UE if at least one of the total amount of CSI-RS resources occupation is smaller than the indicated number of CSI-RS resources supported by the UE or the total amount of CSI-RS ports occupation is smaller than the indicated number of CSI-RS ports supported by the UE.

As noted, in some systems, wireless communications may be enabled with CSI. As used herein, 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-RSs, 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 CQI, 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., gNB) may configure UEs for CSI reporting. For example, the gNB configures the UE with a CSI report configuration (also referred to as a CSI reporting 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 systems (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 use a precoder for a certain layer l on N<NUM> subbands is expressed as a size-P × N<NUM> matrix Wl: <MAT>.

In Wl, L is the number of spatial domain (SD) basis (or bases) (e.g., spatial beams) configured by RRC signaling of the CSI report configuration, <MAT> with i = <NUM>,<NUM>, ···, L - <NUM> is <MAT> SD basis and it is applied to both polarizations. The SD bases are DFT based and the SD basis with index <MAT> and <MAT> is written as <MAT> <MAT> where N<NUM> and N<NUM> represents the first and the second dimension of the configured codebook, respectively. In some cases, they refer to the number of antenna elements on the vertical and horizontal dimension at the base station, respectively. The oversampling factor are denoted by O<NUM> and O<NUM>.

Moreover, <MAT> with m = <NUM>,<NUM>, ··· M is a N<NUM> × <NUM> FD basis (i.e., <MAT> is a <NUM> × N<NUM> row vector) which is also known as the transferred domain basis. Ml is the number of FD bases selected for layer l and it is derived based on RRC configuration. The FD bases may be DFT bases, and the FD basis with index <MAT> is expressed as <MAT>.

Linear combination coefficient comprises three parts, i.e., <MAT>, ϕi,l,m. The parameter <MAT> represents an amplitude reference for the first polarization, while <MAT> represents the amplitude reference for the second polarization. They are common to all the coefficients associated with the corresponding polarization, i.e., <MAT> and <MAT>, ∀i' ∈ {i' ≠ i|i' = <NUM>,<NUM>, ··· L - <NUM>} , ∀m' ∈ {m' ≠ m|m' = <NUM>,<NUM>, ··· M}. Besides, the parameter <MAT> represents a (differential) amplitude the coefficient associated with SD basis with index <MAT> and <MAT> , and associated with the FD basis with index <MAT> in the first polarization, while <MAT> represents a (differential) amplitude the coefficient associated with SD basis with index <MAT> and <MAT>, and associated with the FD basis with index <MAT> in the second polarization. Similarly, the parameter ϕi,m represents a (differential) amplitude the coefficient associated with SD basis with index <MAT> and <MAT>, and associated with the FD basis with index <MAT> in the first polarization, while ϕi+L,m represents a (differential) amplitude the coefficient associated with SD basis with index <MAT> and <MAT>, and associated with the FD basis with index <MAT> in the second polarization.

For RI={<NUM>,<NUM>}, for each layer, the number of FD bases M = M<NUM>,<NUM>, wherein the value of <MAT> is determined by a ratio p configured by RRC and R is the number of precoding matrix indicator (PMI) subbands within one CQI subband. For RI={<NUM>,<NUM>}, the number of FD bases M = M<NUM>,<NUM>, wherein the value of <MAT> is determined by a ratio v<NUM> configured by RRC. Possible combinations of p and v<NUM> include <MAT>. Moreover, for each layer of RI={<NUM>,<NUM>,<NUM>,<NUM>}, the UE is configured to report a subset of total <NUM>LM<NUM>,<NUM> or total <NUM>LM<NUM>,<NUM> coefficients, the unreported coefficients are set to zero. The max number of coefficients to be reported per layer is K<NUM> and the max total number of coefficients to be reported across all layers is <NUM>K<NUM>, where <MAT> and <MAT> is RRC configured. Note that for no matter rank, K<NUM> is calculated using the M<NUM>,<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.

In some systems (e.g., Rel-<NUM>), the UE may be configured to report CSI using a three stage codebook with FD compression. <FIG> shows one reference example of a three-stage codebook with FD compression, in accordance with certain aspects of the present disclosure. <FIG> shows the compressed precoder feedback: <MAT> where i is the ith layer and the precoders for a given layer (e.g., Layer <NUM> or Layer <NUM>) is given by the size Nt × N<NUM>. In some examples, if the number of CQI subbands × R is less than or equal to <NUM> (e.g., # CQI SB × R ≤ <NUM>), then N<NUM> = # CQI SB × R. In some examples (e.g., # CQI SB × R > <NUM>), N<NUM> may be the smallest integer equal to (<NUM>a · <NUM>b · <NUM>c) that is greater than the # CQI SB × R. Alternatively, in some examples (e.g., # CQI SB × R > <NUM>), the PMI subbands are divided into two segments, each segment has size equal to <NUM>a · <NUM>b · <NUM>c, and N<NUM> may be taken as that value. In yet other examples, N<NUM> may be predefined to be equal to # CQI SB × R. L may be common across spatial domains and may have a value selected (e.g., RRC configured) from the following set {<NUM>, <NUM>, <NUM>}. In some cases, L = <NUM> may apply to situations in which RI = {<NUM>, <NUM>}. FD compression may be layer-specific. For example, for <MAT> and for RI = {<NUM>, <NUM>}, <MAT>, where <MAT>, and <MAT> is RRC configured. The non-zero coefficients (NNZC) may also be layer-specific. For example, for each layer of RI = {<NUM>, <NUM>, <NUM>, <NUM>}, the maximum NNZC per layer may be <MAT>, where β = <MAT> is RRC configured and <MAT>. For RI = {<NUM>, <NUM>, <NUM>, <NUM>}, the maximum NNZC across all layers may be <NUM>K<NUM>.

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 in <FIG>, <NUM> 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. 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 <FIG>, 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 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 subband 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 for PMI may be a finer granularity. For example, the subband size for PMI 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 subband size may be equal to the CQI subband size. In some examples, the PMI granularity may be smaller than a CQI granularity. For example, as shown in <FIG>, the PMI subband size may be equal to X, where X = (CQI subband size)/R, and 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). <FIG> shows a particular example where R is equal to <NUM>, such that the number of PMI FD units may be up to <NUM>. In some cases, for the FD compression unit size, the PMI subband size = CQI subband size may be the default configuration, and the PMI subband size = CQI subband size/R may be a secondary configuration. In some cases, whether the secondary configuration is activated and/or supported may be based on one or more parameters, including but not limited to, at least one of a UE capability, a number of FD compression units, CPU occupation, latency constraint, bandwidth constraint, number of simultaneous resources and ports occupation, etc..

As noted, some systems (e.g., Rel. <NUM> and beyond) allow for CSI reporting configurations to be subject to UE capability. <NUM> (and beyond), for example, the UE can signal the maximum number of resources and/or the maximum number of ports per codebook, per band, per carrier aggregation (CA) band combination, etc..

In one aspect, the UE can use the RRC information element "CodebookParameters" to signal the capabilities per codebook per band. For example, as shown in <FIG>, the UE can signal the "maxNumberResourcesPerBand" and "totalNumberTxPortsPerBand" for each type of Type I single panel, type I multi-panel, Rel-<NUM> Type II, Rel-<NUM> Type II port selection, etc..

In one aspect, the UE can use the RRC information element "MIMO-ParametersPerBand" to signal the capabilities per band (e.g., regardless of the codebook type). For example, as shown in <FIG>, the UE can signal the "maxNumberSimultaneousNZP-CSI-RS-PerCC" and "totalNumberPortsSimultaneous NZP-CSI-RS-PerCC" per band.

In one aspect, the UE can use the RRC information element "CA-ParametersNR" to signal the capabilities per band-band combination (e.g., for CA scenarios). For example, as shown in <FIG>, the UE can signal the "maxNumberSimultaneousNZP-CSI-RS-ActBWP-AllCC" and the "totalNumberPorts SimultaneousNZP-CSI-RS-ActBWP-AllCC" for each band-band combination.

Regardless of the capability signaling, the number of resources and the number of ports configured by the gNB (e.g., in each CSI report and across all CSI reports) should be subject to the capability reported by the UE. For example, if the gNB configures N CSI reports, each with M CSI-RS resources, then the configuration should satisfy MN ≤ UE capability (of any of the three aspects described above).

In current systems (e.g., Rel-<NUM>), when determining the CSI reporting configuration subject to the UE capability, if a CSI-RS resource is referred by N CSI reporting settings, then the CSI-RS resource and the CSI-RS ports within the CSI-RS resources are counted N times. However, this approach for determining the CSI-RS resources/ports occupation may not be suitable for Rel-<NUM> systems. For example, as noted, Rel-<NUM> may support a Type II codebook, where the PMI granularity (e.g., PMI FD unit (subband) size) is finer than the CQI granularity (e.g., CQI FD unit (subband) size). In these scenarios, the finer CSI granularity may lead to a much larger CSI computational complexity that is larger than the UE supported processing capability. Accordingly, it may be desirable to provide a new rule for determining the CSI-RS resources/ports occupation that can be used for determining the CSI reporting setting(s) subject to the UE capabilities.

In some aspects, the new rule may apply in situations where a particular codebook (e.g., Rel-<NUM> Type II codebook) is employed. For example, the gNB may use the new rule to determine the CSI-RS resources/ports occupation of each CSI report, and may generate (or determine) a CSI reporting configuration having one or more CSI reports, where the CSI-RS resources/ports occupation in each CSI report is subject to the UE reported capability. Similarly, the UE may report its capabilities (of maximum supported CSI-RS resources/ports) in order to impact the gNB scheduling (e.g., restrict the size of the CSI reporting configuration). The UE may also determine the CSI-RS resources/ports occupation using the new rule in order to determine whether the received CSI reporting configuration is within the UE capabilities. If, for example, the gNB (accidently or mistakenly) schedules one or more CSI reports beyond the UE's capabilities, the UE can treat the extra CSI reports as errors (e.g., by dropping and/or ignoring the additional CSI report(s)), or treat all CSI reports as errors (e.g., by dropping and/or ignoring all CSI reports).

Note that, as used herein, a CSI-RS resource being referred by N CSI reporting settings may correspond to (<NUM>) N configured CSI reporting settings (where all N may not be active, e.g., K out of the N configured CSI reporting settings may be configured and active, and N-K CSI reporting settings may be configured and inactive) or (<NUM>) N simultaneously active CSI reporting settings. Further, note that as used herein, a CSI-RS resource and the ports within it being counted N times may correspond to (<NUM>) counting as N simultaneous CSI-RS resources/N times P simultaneous ports (where P is the # ports within the CSI-RS resource) or (<NUM>) counting as N configured CSI-RS resources/ N times P configured ports (where P is # ports within the CSI-RS resource).

<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 UE (e.g., such as a UE 120a in the wireless communication network <NUM>). The operations <NUM> may be complimentary operations by the UE to the operations <NUM> performed by the BS. 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 UE 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 UE 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>, where the UE receives a CSI reporting configuration that includes one or more CSI reporting settings. Each CSI reporting setting is associated with one or more subbands for CSI. Each subband for CSI includes a FD unit for CQI feedback and one or more FD units for PMI feedback. In some aspects, the CSI reporting configuration may include a CSI request that triggers one or more of the CSI reporting settings. For example, the CSI request may trigger a CSI reporting state, which activates one or more preconfigured CSI reporting settings. In one example, the preconfiguration of the CSI reporting settings may be via RRC signaling. Each CSI reporting setting may include one or more CSI-RS resources, and each CSI-RS resource may include one or more CSI-RS ports.

At <NUM>, the UE determines, for each of the CSI reporting settings, at least one of an amount of CSI-RS resources occupation or an amount of CSI-RS ports occupation, based at least in part on (i) a number of FD units for PMI feedback within a single FD unit for CQI feedback or (ii) a number of FD units for PMI feedback within all of the subbands for CSI. In some aspects, the determination of the amount of CSI-RS resources occupation and/or the amount of CSI-RS ports occupation is further based on a type of codebook associated with the CSI reporting setting. For example, the UE may determine the resources/ports occupation based on (i) or (ii) if the codebook is Rel-<NUM> Type II with FD compression.

The amount of CSI-RS resources occupation and/or the amount of the CSI-RS ports occupation can be based on two types: (<NUM>) configured resources (including active and inactive) and (<NUM>) active resources. Thus, in some aspects, the amount of CSI-RS resources occupation (e.g., in <NUM>) may include an amount of simultaneous active CSI-RS resources occupation and the amount of CSI-RS ports occupation (e.g., in <NUM>) may include an amount of simultaneous active CSI-RS ports occupation.

In some aspects, the operations <NUM> may further include the UE sending an indication of a CSI processing capability of the UE. The CSI processing capability may include an indication of at least one of a number of CSI-RS resources supported by the UE or a number of CSI-RS ports supported by the UE. As part of operations <NUM>, the UE may determine at least one of a total amount of CSI-RS resources occupation or a total amount of CSI-RS ports occupation based at least in part on the determined amount of CSI-RS resources occupation of each CSI reporting setting or the determined amount of CSI-RS ports occupation of each CSI reporting setting. As part of operations <NUM>, the UE may perform CSI calculation and reporting of the one or more CSI reporting settings if at least one of the total amount of CSI-RS resource occupation is smaller than the indicated number of CSI-RS resources supported by the UE or the total amount of CSI-RS ports occupation is smaller than the indicated number of CSI-RS ports supported by the UE.

<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 gNB (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>, where the gNB determines (e.g., as part of a CSI reporting configuration) one or more CSI reporting settings. Each CSI reporting setting is associated with one or more subbands for CSI. Each subband for CSI includes a FD unit for CQI feedback and one or more FD units for PMI feedback.

At <NUM>, the gNB determines, for each of the CSI reporting settings, at least one of an amount of CSI-RS resources occupation or an amount of CSI-RS ports occupation, based at least in part on (i) a number of FD units for PMI feedback within a single FD unit for CQI feedback or (ii) a number of FD units for PMI feedback within all of the subbands for CSI. In some aspects, the determination of the amount of CSI-RS resources occupation and/or the amount of CSI-RS ports occupation is further based on a type of codebook associated with the CSI reporting setting. For example, the gNB may determine the resources/ports occupation based on (i) or (ii) if the codebook is Rel-<NUM> Type II with FD compression.

In some aspects, the operations <NUM> may further include the gNB receiving an indication of a CSI processing capability of the UE. The CSI processing capability may include an indication of at least one of a number of CSI-RS resources supported by the UE or a number of CSI-RS ports supported by the UE. As part of operations <NUM>, the gNB may determine at least one of a total amount of CSI-RS resource occupation or a total amount of CSI-RS ports occupation based at least in part on the determined amount of CSI-RS resource occupation of each CSI reporting setting or the determined amount of CSI-RS ports occupation of each CSI reporting setting. As part of operations <NUM>, the gNB may signal a CSI reporting configuration including the one or more CSI reporting settings to the UE if at least one of the total amount of CSI-RS resources occupation is smaller than the indicated number of CSI-RS resources supported by the UE or the total amount of CSI-RS ports occupation is smaller than the indicated number of CSI-RS ports supported by the UE.

In some aspects, the CSI reporting configuration may include a CSI request that triggers one or more of the CSI reporting settings. For example, the CSI request may trigger a CSI reporting state, which activates one or more preconfigured CSI reporting settings. In one example, the preconfiguration of the CSI reporting settings may be via RRC signaling. Each CSI reporting setting may include one or more CSI-RS resources, and each CSI-RS resource may include one or more CSI-RS ports.

In one aspect, the UE (e.g., as part of operations <NUM>) and/or gNB (e.g., as part of operations <NUM>) may determine at least one of the amount of CSI-RS resources occupation or the amount of CSI-RS ports occupation based on the number of the FD units for PMI feedback within a single FD unit for CQI feedback. That is, the UE and/or gNB may determine the resources and ports occupation based on R, where R is the number of PMI FD units in a single CQI band.

In this aspect, the determination of the amount of the CSI-RS resources occupation and/or the amount of CSI-RS ports occupation may include: counting each CSI-RS resource and each CSI-RS port in the CSI-RS resource based on a first number (e.g., X = A) if the number of FD units for PMI feedback within a single FD unit for CQI feedback is less than or equal to a threshold number (e.g., R = <NUM>); and counting each CSI-RS resource and each CSI-RS port in the CSI-RS resource based on a second number (e.g., X = B) if the number of the FD units for PMI feedback within a single FD unit for CQI feedback is greater than the threshold number (e.g., R = <NUM>), wherein the second number is greater than one.

In some cases, the threshold number may be configured by the gNB via RRC signaling, media access control (MAC) control element (CE) (MACCE) signaling, or downlink control information (DCI) signaling. In some cases, the threshold number can be predetermined in a standard specification (e.g., 3GPP Rel-<NUM> specification). In some cases, the threshold number can be predetermined following a rule based on one or parameters.

For example, if a CSI-RS resource is referred by a CSI reporting setting associated with Rel-<NUM> Type II, then the CSI-RS resource and the CSI-RS ports within the CSI-RS resource may be counted X ≥ <NUM> times, where X may be dependent on R, which is configured by the gNB (e.g., as noted, R is the number of PMI FD units within one CQI subband). For example, in one aspect, X = R. In another aspect, X = A (or a first number) (e.g., if R= <NUM>) and X = B (or a second number) (e.g., if R = <NUM>), where A < B and A ≥ <NUM>. Thus, in these examples, assuming R =<NUM>, then a CSI-RS resource (referred by a CSI reporting setting associated with Rel-<NUM> Type II) and the CSI-RS ports within the CSI-RS resource would be counted (at least) twice.

In general, the above aspect may be stated as the following rule: if a CSI-RS resource is referred by N CSI reporting settings associated with Rel-<NUM> Type II and R = <NUM>, then the CSI-RS resource and the CSI-RS ports within the CSI-RS resource can be counted X*N times, where X ≥ <NUM>. For example, assume that a CSI-RS resource is referred by N CSI reporting settings, where N<NUM> CSI reporting settings (out of the N CSI reporting settings) are associated with Rel-<NUM> Type II with R = <NUM>, N<NUM> CSI reporting settings (out of the N CSI reporting settings) are associated with Rel-<NUM> Type II with R = <NUM>, and N - N<NUM> - N<NUM> CSI reporting settings are associated with other types of CSI codebooks. Using the above rule with X = <NUM>, in this example, the CSI-RS resource and the CSI-RS ports within the CSI-RS resource would be counted N + N<NUM> times. This result is obtained by counting the resources/ports N - N<NUM> - N<NUM> times (for all other types of CSI codebooks), counting the resources/ports N<NUM> times (for Rel-<NUM> with R = <NUM>), and counting the resources/ports <NUM>*N<NUM> times (for Rel-<NUM> with R = <NUM>), so that (N - N<NUM> - N<NUM>) + N<NUM> + (N<NUM> + N<NUM>) = N + N<NUM>.

In one aspect, the UE (e.g., as part of operations <NUM>) and/or gNB (e.g., as part of operations <NUM>) may determine at least one of the amount of CSI-RS resources occupation or the amount of CSI-RS ports occupation based on the number of the FD units for PMI feedback within all of the subbands for CSI. That is, the UE and/or gNB may determine the resources and ports occupation based on the number of PMI FD units (associated with the configured subbands).

In this aspect, the determination of the amount of the CSI-RS resources occupation and/or the amount of CSI-RS ports occupation may include: counting each CSI-RS resource and each CSI-RS port in the CSI-RS resource based on a first number (e.g., X = A) if the number of the FD units for PMI feedback within all of the subbands for CSI feedback is less than or equal to a threshold number of FD units for PMI feedback; and counting each CSI-RS resource and each CSI-RS port in the CSI-RS resource based on a second number (e.g., X = B) if the number of the FD units for PMI feedback within all of the subbands for CSI feedback is greater than the threshold number of FD units for PMI feedback, wherein the second number is greater than one. In one aspect, the number of the FD units for PMI feedback may be equal to a number of FD units used for reporting CSI with FD compression (e.g., also referred to as N<NUM>). In one aspect, the number of the FD units for PMI feedback may be equal to the number of the FD units for CQI feedback times the number of FD units for PMI feedback within each FD unit for CQI feedback (e.g., also referred to as # CQI SB × R).

In some cases, the threshold number of FD units for PMI feedback may be configured by the gNB via RRC signaling, media access control (MAC) control element (CE) (MACCE) signaling, or downlink control information (DCI) signaling. In some cases, the threshold number of FD units for PMI feedback can be predetermined in a standard specification (e.g., 3GPP Rel-<NUM> specification). In some cases, the threshold number of FD units for PMI feedback can be predetermined following a rule based on one or parameters.

In one example, if a CSI-RS resource is referred by a CSI reporting setting associated with Rel-<NUM> Type II, then the CSI-RS resource and the CSI-RS ports within the CSI-RS resource may be counted X ≥ <NUM> times, where X may be dependent on the # PMI units, which is configured by the gNB (e.g., as noted, # PMI FD units is associated with the number of configured subbands). For example, in one aspect, X = A (or a first number) (e.g., if # PMI units ≤ threshold) and X = B (or a second number) (e.g., if # PMI units > threshold), where A < B and A ≥ <NUM>. In one particular example, A = <NUM> and B = <NUM>. In one particular example, the threshold may be equal to <NUM> (e.g., same as the maximum number of subbands in Rel-<NUM>). In this aspect, assuming the # PMI units > <NUM>, then a CSI-RS resource (referred by a CSI reporting setting associated with Rel-<NUM> Type II) and the CSI-RS ports within the CSI-RS resource would be counted (at least) twice.

In general, the above aspect may be stated as the following rule: if a CSI-RS resource is referred by N CSI reporting settings associated with Rel-<NUM> Type II and the # PMI units > threshold, then the CSI-RS resource and the CSI-RS ports within the CSI-RS resource can be counted X*N times, where X ≥ <NUM>. For example, assume that a CSI-RS resource is referred by N CSI reporting settings, where N<NUM> CSI reporting settings (out of the N CSI reporting settings) are associated with Rel-<NUM> Type II with # PMI units ≤ threshold, N<NUM> CSI reporting settings (out of the N CSI reporting settings) are associated with Rel-<NUM> Type II with # PMI units > threshold, and N - N<NUM> - N<NUM> CSI reporting settings are associated with other types of CSI codebooks. Using the above rule with X = <NUM>, in this example, the CSI-RS resource and the CSI-RS ports within the CSI-RS resource would be counted N + N<NUM> times. This result is obtained by counting the resources/ports N - N<NUM> - N<NUM> times (for all other types of CSI codebooks), counting the resources/ports N<NUM> times (for Rel-<NUM> with # PMI units ≤ threshold), and counting the resources/ports <NUM>*N<NUM> times (for Rel-<NUM> with # PMI units > threshold), so that (N - N<NUM> - N<NUM>) + N<NUM> + (N<NUM> + N<NUM>) = N + N<NUM>.

The transceiver <NUM> is configured to transmit and receive signals for the communications device <NUM> via an antenna <NUM>, such as the various signals described herein.

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 that when executed by processor <NUM>, cause the processor <NUM> to perform the operations illustrated in <FIG> and/or other operations for performing the various techniques discussed herein.

In certain aspects, the processing system <NUM> further includes a communicating component <NUM> for performing the operations illustrated at <NUM> in <FIG> and/or other communication operations described herein. Additionally, the processing system <NUM> includes a CSI reporting component <NUM> for performing the operations illustrated at <NUM> in <FIG> and/or operations described herein. The communicating component <NUM> and CSI reporting component <NUM> may be coupled to the processor <NUM> via bus <NUM>. In certain aspects, the communicating component <NUM> and CSI reporting component <NUM> may be hardware circuits. In certain aspects, the communicating component <NUM> and CSI reporting component <NUM> may be software components that are executed and run on processor <NUM>.

In certain aspects, the processing system <NUM> further includes a communicating component <NUM> for performing the communication operations described herein. Additionally, the processing system <NUM> includes a CSI reporting component <NUM> for performing the operations illustrated at <NUM> and <NUM> in <FIG> and/or operations described herein. The communicating component <NUM> and CSI reporting component <NUM> may be coupled to the processor <NUM> via bus <NUM>. In certain aspects, the communicating component <NUM> and CSI reporting component <NUM> may be hardware circuits. In certain aspects, the communicating component <NUM> and CSI reporting component <NUM> may be software components that are executed and run on processor <NUM>.

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 control information may be for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), PDCCH, group common PDCCH (GC PDCCH), etc. The data may be for the PDSCH, etc. The processor <NUM> may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor <NUM> may also generate reference symbols, such as for the primary synchronization signal (PSS), secondary synchronization signal (SSS), and cell-specific reference signal (CRS). 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) 1132a- 1132t. Downlink signals from modulators 1132a- 1132t may be transmitted via the antennas 1134a-1134t, respectively.

At the UE 120a, the antennas 1152a- 1152r may receive the downlink signals from the BS 110a and may provide received signals to the demodulators (DEMODs) in transceivers 1154a- 1154r, respectively. A MIMO detector <NUM> may obtain received symbols from all the demodulators 1154a- 1154r, 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 demodulators in transceivers 1154a- 1154r (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.

The controller/processor <NUM> and/or other processors and modules at the UE 120a may perform or direct the execution of processes for the techniques described herein. For example, as shown in <FIG>, the controller/processor <NUM> of the UE 120a has a CSI reporting component <NUM>, which is configured to implement one or more techniques described herein for determining CSI-RS resources/ports occupation, according to aspects described herein. Similarly, controller/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. For example, as shown in <FIG>, the controller/processor <NUM> of the BS 110a has a CSI reporting component <NUM>, which is configured to implement one or more techniques described herein for determining CSI-RS resources/ports occupation, according to aspects described herein. Although shown at the Controller/Processor, other components of the UE 120a and BS 110a may be used performing the operations described herein.

For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein, for example, instructions for performing the operations described herein and illustrated in <FIG> and/or <FIG>.

Claim 1:
A method for wireless communication by a user equipment, UE, comprising:
receiving (<NUM>) a channel state information, CSI, reporting configuration comprising one or more CSI reporting settings, wherein each CSI reporting setting is associated with one or more subbands for CSI and each subband for CSI comprises a frequency domain, FD, unit for channel quality information, CQI, feedback and one or more FD units for precoding matrix indicator, PMI, feedback; and
determining (<NUM>), for each of the CSI reporting settings, at least one of an amount of CSI reference signal, CSI-RS, resources occupation or an amount of CSI-RS ports occupation, based at least in part on (i) a number of the FD units for PMI feedback within a single FD unit for CQI feedback or (ii) a number of FD units for PMI feedback within all of the subbands for CSI,
wherein determining at least one of the amount of CSI-RS resource occupation or the amount of CSI-RS ports occupation is further based on a type of codebook associated with the CSI reporting setting; and
further comprising:
sending an indication of a CSI processing capability of the UE, the CSI processing capability comprising an indication of at least one of a number of CSI-RS resources supported by the UE or a number of CSI-RS ports supported by the UE.