Patent Description:
The present disclosure relates generally to communication systems, and more particularly, to channel state information reporting.

A user equipment (UE) may transmit channel state information (CSI) to the network to improve downlink transmissions. For example, the CSI may include a channel quality indicator (CQI) and/or beamforming information such as a precoding matrix indicator (PMI). As multiple-input multiple-output (MIMO) systems become more complicated, a UE may be able to provide a large amount of CSI. Systems and methods to improve efficiency in transmitting of CSI may be desirable. <NPL>), discusses CSI Enhancement for MU-MIMO Support,.

The present invention is defined by the attached independent claims. Other preferred embodiments may be found in the dependent claims.

The time and frequency resources that can be used by the UE to report channel state information (CSI) may be controlled by the network (e.g., a base station or gNB). CSI may include 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. Existing CSI schemes (e.g., 3GPP <NUM> NR Release-<NUM>) may define PMI based on a multiple layers, multiple beams, and coefficients for frequency domain (FD) units. For example, a precoder for a layer, r, across N<NUM> FD units may be defined by the equation: <MAT> where L is the number of beams, bi is the ith beam, ci is the coefficient matrix having a length of N<NUM>. N<NUM> may correspond to a number of FD units such as, for example, sub-bands (SB), resource blocks, or groups of resource blocks. A UE may compute a precoder for each SB. The UE may find a PMI that matches the precoder best on each SB. In Release-<NUM>, number of frequency domain PMI is equal to the number of SB for which a PMI report is required. The network may indicate a reporting band identifying for which SB the UE should report a PMI. Based on the configuration of a bandwidth part (BWP) size and SB size, the network and UE may determine the total number of SBs in the configured BWP, the network may further send a configuration including a bit mask with a length equal to the number of SBs. For example, a value of "<NUM>" in the bit mask may indicate that the UE should report the PMI, and a value of "<NUM>" may indicate that the UE does not need to report the PMI. Accordingly, as the number of SB increases, the size of the coefficient matrix for reporting PMI may also increase. In order to reduce overhead of PMI, a new CSI codebook with frequency domain compression may be desirable.

In an aspect, frequency domain compression may be used to reduce the size of the coefficient matrix reported. For example, in this aspect, a precoder may be defined as: <MAT> where <MAT> is a discrete Fourier transform (DFT) basis of size Mi × N<NUM> and the coefficient matrix c̃i is of length Mi, where Mi is a the number of basis selected for the ith beam, and equivalently it is also the number of coefficients associated with the ith beam. For some cases, UE performs a beam-common basis selection. That is, a same set of bases is selected for all beams, i.e., M_i=M for all i, and F_i=F for all i. for the ith beam. M may be configured via upper layer signaling with a common value for all beams. In some cases, the UE may perform beam specific basis selection, where Mi < N<NUM> bases are selected for a particular beam. Accordingly, frequency domain compression may reduce the size of the coefficient matrix from ci having length N<NUM> to c̃i having length Mi.

Frequency domain compression may pose several difficulties. First, defining N<NUM> based on a number of configured FD units may result in many possible values of N<NUM>. Accordingly, a UE may need to store many different DFT bases (corresponding to each N<NUM> value) and switch among the different DFT bases according to the triggered CSI reporting. Additionally, some values of N<NUM> (e.g., prime numbers other than <NUM>, <NUM>, or <NUM>, and their multiples) maybe inefficient for computation of DFT bases. Second, non-contiguous selection of FD units to be reported may result in inefficient or inaccurate compression. Third, as a finer granularity for PMI may be adopted, the FD units may not correspond to a SB for which a CQI report is required. Instead, it may consist of X RBs and X can be equal to <NUM>, <NUM>, <NUM> or CQI SBSize/R. In this way, the value of total number of FD units may increase, which may lead to a large value of N<NUM>.

In an aspect, the present disclosure provides an alternative and efficient PMI reporting technique. The value of N<NUM> may be selected to span a CSI reporting band. The value of N<NUM> may be selected from a set of defined values, which may be multiples of <NUM>, <NUM>, or <NUM>, for efficient DFT bases. Additionally, limiting the potential values of N<NUM> may reduce the number of possible values of DFT sizes. For example, the number of FD units may be determined based on an ending index of a FD unit minus a starting index of an FD unit plus one, regardless of whether the FD units are contiguous. N<NUM> may be selected as the minimum value greater than or equal to the number of FD units. When N<NUM> is greater than the number of FD units, the UE may use a mapping rule to determine where to locate the FD units in the N<NUM> reported units.

In another aspect, some potential CSI configurations may be inefficient or the UE may not be capable of generating the requested CSI report in a timely manner. The present disclosure provides for the UE to be configured with one or more thresholds for restricting CSI configurations. The UE may provide the thresholds to the network as one or more UE capability indications. If the UE does receive a CSI configuration that satisfies the thresholds for exclusion, the UE may ignore the CSI configuration, drop the CSI report, send a previous CSI report, reduce the content of the CSI report, or fallback to a CSI report without frequency domain compression.

<FIG> is a diagram illustrating an example of a wireless communications system and an access network <NUM> including one or more UEs <NUM> configured to perform efficient CSI reporting using FD compression. The wireless communications system (also referred to as a wireless wide area network (WWAN)) includes base stations <NUM>, the one or more UEs <NUM>, an Evolved Packet Core (EPC) <NUM>, and a <NUM> Core (5GC) <NUM>. In certain aspects, the UE <NUM> may include a CSI component <NUM> configured to report PMI using FD compression and sub-band or FD unit restriction. In an aspect, for example, the CSI component <NUM> may include an FD restriction component <NUM> for determining a set of FD units for reporting, a FD compression component <NUM> for generating a compressed coefficient matrix, a mapping component <NUM> for mapping a PMI for a FD unit to a reported FD unit according to a mapping rule, and a threshold component <NUM> for using threshold values to determine whether the UE should report a CSI including PMI. Further details regarding the UE <NUM> executing the CSI component <NUM> are described below, particularly with regard to <FIG>.

The base stations <NUM> may include a communications component <NUM> for performing complementary operations with the CSI component <NUM>. For example, the communications component <NUM> may receive CSI reports using FD compression and determine the reported FD unis based on the mapping rule. The communications component <NUM> may also receive UE capabilities from the UE <NUM> and transmit CSI configurations to the UE <NUM>.

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 5GC <NUM> through backhaul links <NUM>. In addition to other functions, the base stations <NUM> may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), intercell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations <NUM> may communicate directly or indirectly (e.g., through the EPC <NUM> or 5GC <NUM>) with each other over backhaul links <NUM> (e.g., X2 interface).

A network that includes both small cell and macro cells may be known as a heterogeneous network. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL).

A base station <NUM>, whether a small cell <NUM>' or a large cell (e.g., macro base station), may include an eNB, gNodeB (gNB), or other type of base station.

The 5GC <NUM> may include an Access and Mobility Management Function (AMF) <NUM>, other AMFs <NUM>, a Session Management Function (SMF) <NUM>, and a User Plane Function (UPF) <NUM>. The AMF <NUM> is the control node that processes the signaling between the UEs <NUM> and the 5GC <NUM>.

The base station <NUM> provides an access point to the EPC <NUM> or 5GC <NUM> for a UE <NUM>.

<FIG> include example frame structures and resources and/or channels that may be used for communication between the UEs <NUM> and the base stations <NUM> in network <NUM>. The example frame structures and resources include resources (e.g., CSI-RS) for determining CSI and channels (e.g., PUCCH and PUSCH) for reporting CSI.

The subcarrier spacing may be equal to <NUM>µ * <NUM> kKz, where µ is the numerology <NUM> to <NUM>. The subcarrier spacing is <NUM> and symbol duration is approximately <NUM> ps.

<FIG> is a block diagram of a base station <NUM> in communication with a UE <NUM> in an access network, where base station <NUM> may be an example implementation of base station <NUM> and where UE <NUM> may be an example implementation of UE <NUM>. Accordingly, the UE <NUM> may include a CSI component <NUM> for generating a CSI based on reference signals and reporting the CSI to the base station <NUM>.

The CSI component <NUM> may also operate on received reference signals to generate a CSI report as described herein.

<FIG> is a diagram <NUM> illustrating a base station <NUM> in communication with a UE <NUM> using beamforming, where base station <NUM> may be an example implementation of base station <NUM> and where UE <NUM> may be an example implementation of UE <NUM>. In an aspect, the CSI reported by the UE <NUM> may include PMI for the base station <NUM> to select the correct beam. The base station <NUM> may transmit a beamformed signal to the UE <NUM> in one or more of the directions 402a, 402b, 402c, 402d, 402e, 402f, <NUM>, <NUM>. The UE <NUM> may receive the beamformed signal from the base station <NUM> in one or more receive directions 404a, 404b, 404c, 404d. The UE <NUM> may also transmit a beamformed signal to the base station <NUM> in one or more of the directions 404a-404d. The base station <NUM> may receive the beamformed signal from the UE <NUM> in one or more of the receive directions 402a-<NUM>.

Referring to <FIG>, a diagram <NUM> illustrates example mappings of configured FD units to reported FD units for an example set of contiguous SBs. For example, the UE <NUM> may receive, from the base station <NUM>, a CSI configuration including a bit mask <NUM> indicating that a set of configured FD units <NUM> includes <NUM> contiguous SBs that should be reported out of <NUM> configured SBs <NUM>. The UE <NUM> via execution of the CSI component <NUM> and or FD restriction component <NUM> may determine an N<NUM> value of <NUM> FD units to span the indicated SBs. For example, <NUM> may be the minimum defined N<NUM> value greater than or equal to the number of SBs configured for reporting, e.g., greater than <NUM>. In one example implementation, using a first mapping rule, the UE <NUM> via execution of the mapping component <NUM> may map the <NUM> PMIs corresponding to set of configured FD units <NUM> (i.e., the <NUM> contiguous SBs) to the first <NUM> reported FD units starting at the first reported FD unit <NUM>. In another example implementation, using a second mapping rule, the UE <NUM> may map the <NUM> PMIs to the last <NUM> reported FD units ending at the last reported FD unit <NUM>. In yet another example implementation, using a third mapping rule, the UE <NUM> may map the <NUM> PMIs to a middle <NUM> reported FD units <NUM>. For Example, a number of units may be denoted <MAT> StartingFDindex , then the first configured FD unit corresponds to the <MAT> unit of the reported N<NUM> units.

Referring to <FIG>, a diagram <NUM> illustrates example mappings of configured FD units to reported FD units for an example set of non-contiguous SBs. For example, the UE <NUM> may receive, from the base station <NUM>, a CSI configuration including a bit mask <NUM> indicating set of configured FD units <NUM> to be reported, including a first subset <NUM> of <NUM> FD units and a second subset <NUM> of <NUM> FD units. Accordingly, there may be <NUM> SDs for reporting, but a number of FD units spanned by the set of configured FD units <NUM> indicated by bit mask <NUM>, based on ending and starting indices (e.g., <NUM> minus <NUM> plus <NUM>), may be <NUM>. The UE <NUM> via execution of the CSI component <NUM> and/or FD restriction component <NUM> may select an N<NUM> value of <NUM> FD units from the defined N<NUM> values to span the indicated SBs. In one example implementation, using a first mapping rule, the UE <NUM> may map the <NUM> PMIs corresponding to the <NUM> FD units spanned by the set of configured FD units <NUM> to the first <NUM> reported FD units starting at the first reported FD unit <NUM>. In another example implementation, using a second mapping rule, the UE <NUM> may map the <NUM> PMIs corresponding to the <NUM> FD units spanned by the set of configured FD units <NUM> to the last <NUM> reported FD units ending at the last reported FD unit <NUM>. In yet another example implementation, using a third mapping rule, the UE <NUM> may map the <NUM> PMIs corresponding to the <NUM> FD units spanned by the set of configured FD units <NUM> to a middle <NUM> reported FD units <NUM>.

In another aspect, the UE <NUM> may execute the FD restriction component <NUM> to decide the value of N<NUM> using FD unit restriction. The UE <NUM> via the FD restriction component <NUM> may define a threshold number of resource blocks, which may be dependent on at least a BWP size. The UE <NUM> may report the threshold number of resource blocks as a UE capability to the base station <NUM>. The UE <NUM> may receive, from the base station <NUM>, a first FD unit configuration for PMI granularity (e.g., X RBs, where X is a whole number). The UE <NUM> may receive, from the base station <NUM>, a second configuration for determining the number of FD units requested by the base station <NUM>. In an aspect, the UE <NUM> may understand a rule that it will not be configured with a PMI granularity less than the threshold number of resource blocks. If the PMI granularity of the first FD unit configuration is less than the threshold number of resource blocks, the UE may treat the first configuration as an invalid configuration and ignore or drop an associated CSI report. Alternatively, in this case, the UE <NUM> may not update the CSI information, for example, instead the UE may report a previous CSI report.

In another aspect, the UE <NUM> via the FD restriction component <NUM> may define a threshold number of FD units. The UE <NUM> may report the threshold number of FD units as a UE capability to the base station <NUM>. Alternatively, the threshold number of FD units may be defined in a standards document, e.g., a 3GPP standard. The UE <NUM> may understand a rule that it will not be configured with a greater number of FD units than the threshold number of FD units. If a CSI configuration indicates a number of FD units greater than the threshold number of FD units, the UE <NUM> may treat the CSI configuration as an invalid configuration and ignore or drop the corresponding CSI report. Alternatively, the UE <NUM> may not update the CSI information, for example, and may instead transmit a previous CSI report. As another alternative, the UE <NUM> may report a CSI for the threshold number of FD units out of the number of configured FD units, using the threshold number of FD units to determine the N<NUM> value. The UE <NUM> may also define a second threshold defining a minimum number of FD units. The UE <NUM> may drop the CSI report or refrain from using FD compression if the configured number of FD units is less than the second threshold.

In another aspect, the UE <NUM> via the FD restriction component <NUM> may define a threshold value of N<NUM>. The UE <NUM> may report the threshold value of N<NUM> as a UE capability to the base station <NUM>. Alternatively, the threshold value of N<NUM> may be defined in a standards document, e.g., a 3GPP standard. The UE <NUM> may understand a rule that it will not be configured with a greater value of N<NUM> than the threshold value of N<NUM>. If a CSI configuration (explicitly or implicitly) indicates a value of N<NUM> greater than the threshold value of N<NUM>, the UE <NUM> may treat the CSI configuration as an invalid configuration and ignore or drop the corresponding CSI report. Alternatively, the UE <NUM> may not update the CSI information, for example, and instead may transmit a previous CSI report. As another alternative, the UE <NUM> may report a CSI for the maximum number of FD units that results in the N<NUM> value being equal to the threshold value of N<NUM>.

In another aspect, a first configuration of PMI granularity may explicitly configure the number of RBs via higher-layer signaling (e.g., RRC configuration). For example, the UE <NUM> may receive higher-layer signaling that may indicate a factor R (e.g., <NUM>, <NUM>, or <NUM>) indicating how many FD units are in each SB.

For a second configuration of active FD units, the network (e.g., the base station <NUM>) may transmit a SB mask similar to described above with respect to Release <NUM>. The UE <NUM> may report PMI for each of the R FD units of each configured SB. The CQI for each configured SB may be computed using the PMIs on the associated R FD units. Alternatively, a different bit mask may have a size based on the total number of FD units in the BWP. There may be a link between the CQI SB mask and the PMI FD-unit mask. The CQI for each configured SB may be computed using all of the associated PMIs in the CQI SB. In an aspect, the number of FD units within each SB may be different. For example, if the total number of FD units is not evenly divisible by the number of SBs. For a CQI SB with no PMI FD unit, the UE may determine the configuration is invalid and drop the CSI, not update the CSI, or determine a default CQI or random CQI. For a PMI FD unit associated with no CQI SB, the UE may not report CQI, or the UE may not report PMI for that FD unit; and the UE may report a WB CQI considering the PMIs of all the FD units including the FD units associated with no CQI SB.

<FIG> illustrates a flow chart of an example of a method <NUM> for transmitting a CSI report utilizing FD compression. The method <NUM> may be performed by a UE (such as the UE <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 CSI component <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM>). The method <NUM> may be performed by the CSI component <NUM> in communication with the communications component <NUM> of the base station <NUM>.

In block <NUM>, the method <NUM> may include receiving a CSI configuration specifying a first set of configured FD units to be reported. In an aspect, for example, the UE <NUM>, the RX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the FD restriction component <NUM> to receive the CSI configuration specifying the first set of configured FD units to be reported. For instance, the first set of configured FD units may be a bit mask with a number of bits equal to a number of configured sub-bands or FD units in the bandwidth part. For example, as illustrated in <FIG>, there may be a maximum of <NUM> sub-bands in a bandwidth part. A value of "<NUM>" may indicate that the corresponding sub-band or FD unit is in the set of configured FD units to be reported. The bit mask may indicate a contiguous set or a non-contiguous set including multiple groups. Accordingly, the UE <NUM>, RX processor <NUM> or the controller/processor <NUM> executing the CSI component <NUM> and/or the FD restriction component <NUM> may provide means for receiving a CSI configuration specifying a first set of configured FD units to be reported.

In block <NUM>, the method <NUM> may include determining a first number of FD units based on the first set of configured FD units. In an aspect, for example, the UE <NUM>, the RX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the FD restriction component <NUM> to determine the first number of FD units based on the first set of configured FD units. For example, the first number of FD units may be the number of FD units spanned by the first set of configured FD units to be reported. For example, the number of FD units spanned by the first set of configured FD units to be reported may be determined by subtracting the index of the first FD unit in the set from the index of the last FD unit in the set and adding one. Accordingly, the UE <NUM>, RX processor <NUM> or the controller/processor <NUM> executing the CSI component <NUM> and/or the FD restriction component <NUM> may provide means for determining a first number of FD units based on the first set of configured FD units.

In block <NUM>, the method <NUM> may include selecting a second number of FD units that is greater than or equal to the first number of FD units. In an aspect, for example, the UE <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the FD compression component <NUM> to select the second number of FD units that is greater than or equal to the first number of FD units. The second number of FD units may be used for frequency domain compression. For instance, the UE <NUM> may be configured with a set of defined frequency domain coefficient dimensions that may be used for efficient frequency domain compression. For example, the defined frequency domain coefficient dimensions may be multiples of <NUM>, <NUM>, or <NUM>. In an aspect, for example, potential defined frequency domain coefficient dimensions may include <NUM>, <NUM>, <NUM>, and <NUM> when the FD unit is a sub-band. Larger frequency domain coefficient dimensions may be used if smaller FD units are defined. The FD compression component <NUM> may select the minimum defined frequency domain coefficient dimension that is greater than or equal to the first number of FD units as the second number of FD units. Accordingly, the UE <NUM>, TX processor <NUM>, RX processor <NUM> or the controller/processor <NUM> executing the CSI component <NUM> and/or the FD compression component <NUM> may provide means for selecting a second number of FD units that is greater than or equal to the first number of FD units.

In block <NUM>, the method <NUM> may include calculating, for one or more layers, a PMI for a second set of FD units including a number of FD units equal to the second number of FD units. In an aspect, for example, the UE <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the FD compression component <NUM> to calculate, for one or more layers, a PMI for a second set of FD units including a number of FD units equal to the second number of FD units. In an aspect, calculating the PMI may include determining a compressed coefficient matrix using the second number of FD units and a reduced basis as discrete Fourier transform bases. The compressed coefficient matrix may represent a PMI for a respective configured FD unit. For example, the FD compression component <NUM> may determine a precoder wr according to the following formula, <MAT> where <MAT> is the discrete Fourier transform bases of size Mi × N<NUM>, c̃i is the compressed coefficient matrix, bi is the ith beam, and L is the number of layers. N<NUM> may be set to the second number of FD units. In an aspect, the PMI may include at least one of a wideband spatial beam selection, a frequency domain compression basis selection wherein a dimension of the bases is equal to the second number of FD units, and a coefficient matrix associated with the beam and bases. Accordingly, the UE <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM> executing the CSI component <NUM> and/or the FD compression component <NUM> may provide means for calculating, for one or more layers, a PMI for a second set of FD units including a number of FD units equal to the second number of FD units.

In block <NUM>, the method <NUM> may include allocating, according to a mapping rule, a number of PMIs for the first set of FD units to a subset of the PMIs for the second set of FD units. In an aspect, for example, the UE <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the mapping component <NUM> to allocate, according to a mapping rule, a number of PMIs for the first set of FD units to a subset of the PMIs for the second set of FD units. That is, using the above technique, the FD compression component <NUM> may generate a number of PMI equal to N<NUM>, which may be greater than the number of configured FD units to be reported. To ensure that the base station <NUM> is able to determine which reported PMIs correspond to the requested FD units, the UE <NUM> may allocate the set of configured FD units to be reported among the N<NUM> reported FD units according to a configured mapping rule known to both the UE <NUM> and the base station <NUM>. Accordingly, the UE <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM> executing the CSI component <NUM> and/or the mapping component <NUM> may provide means for allocating, according to a mapping rule, a number of PMIs for the first set of FD units to a subset of the PMIs for the second set of FD units.

For example, in sub-block <NUM>, the block <NUM> may include mapping a PMI for a first FD unit in the first set of configured FD units to be reported to a PMI for a first FD unit in the second set of FD units. In an aspect, for example, the CSI component <NUM> may execute the mapping component <NUM> to map the PMI for the first FD unit in the first set of configured FD units to be reported to the PMI for the first FD unit in the second set of FD units. For instance, as illustrated in <FIG>, the first configured FD unit is allocated to the first reported PMI in the first reported FD unit <NUM>. Similarly, as illustrated in <FIG>, the first configured FD unit is allocated to the first reported PMI for the first reported FD unit <NUM>. The other configured FD unit in the set of configured FD units to be reported may be mapped sequentially from the first reported FD unit <NUM>.

As another example, in sub-block <NUM>, the block <NUM> may include a PMI for a last FD unit in the first set of configured FD units to be reported to a PMI for a last FD unit in the second set of FD units PMI. In an aspect, for example, the CSI component <NUM> may execute the mapping component <NUM> to map the PMI for a last FD unit in the first set of configured FD units <NUM>, <NUM> to a PMI for a last FD unit <NUM>, <NUM> in the second set of FD units. The other configured FD units in the first set of configured FD units <NUM>, <NUM> may be mapped in reverse sequence from the last reported FD unit <NUM>, <NUM>.

As a third example, in sub-block <NUM>, the block <NUM> may include mapping PMIs for the first set of FD units to number of PMIs equal to the number of FD units spanned by the first set of FD units located in the middle of the PMIs for the second set of FD units. In an aspect, for example, the CSI component <NUM> may execute the mapping component <NUM> to map PMIs for the first set of FD units <NUM> to number of PMIs equal to the number of FD units spanned by the first set of FD units located in the middle of the PMIs for the second set of FD units <NUM>, <NUM>.

In block <NUM>, the method <NUM> may include transmitting a CSI report including the PMIs for the second set of FD units. In an aspect, for example, the UE <NUM>, TX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> to transmit the CSI report including the PMIs for the second set of FD units. Accordingly, the UE <NUM>, TX processor <NUM> or the controller/processor <NUM> executing the CSI component <NUM> may provide means for transmitting a CSI report including the PMIs for the second set of FD units.

<FIG> illustrates a flow chart of an example of a method <NUM> for transmitting a CSI report utilizing FD compression. The method <NUM> may be performed by a UE (such as the UE <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 CSI component <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM>). The method <NUM> may be performed by the CSI component <NUM> in communication with the communications component <NUM> of the base station <NUM>. The method <NUM> may be performed in conjunction with the method <NUM>.

In block <NUM>, the method <NUM> may optionally include determining a FD unit threshold based on a configured bandwidth part size. In an aspect, for example, the UE <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the threshold component <NUM> to determine the FD unit threshold based on the configured bandwidth part size. For instance, the FD unit threshold may be a minimum number of resource blocks for a precoding matrix indicator granularity, a maximum number of FD units for which to report channel state information, a minimum number of FD units for which to report channel state information, a maximum frequency domain dimension for frequency domain compression (e.g., a maximum N<NUM> value). The threshold component <NUM> may be configured with one or more FD unit thresholds and/or rules, tables, or formulas for determining the one or more FD unit thresholds based on the BWP size. Accordingly, the UE <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM> executing the CSI component <NUM> and/or the threshold component <NUM> may provide means for determining a FD unit threshold based on a configured bandwidth part size.

In block <NUM>, the method <NUM> may optionally include reporting the FD unit threshold as a UE capability. In an aspect, for example, the UE <NUM>, TX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the threshold component <NUM> to report the FD unit threshold as a UE capability (e.g., using RRC signaling). For example, an information element may be defined for one or more FD unit thresholds and the threshold component <NUM> may report each applicable FD unit threshold. Accordingly, the UE <NUM>, TX processor <NUM>, or the controller/processor <NUM> executing the CSI component <NUM> and/or the threshold component <NUM> may provide means reporting the FD unit threshold as a UE capability.

In block <NUM>, the method <NUM> includes receiving a first frequency domain unit configuration indicating a precoding matrix indicator granularity. In an aspect, for example, the UE <NUM>, the RX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the FD restriction component <NUM> to receive the first frequency domain unit configuration indicating the precoding matrix indicator granularity. The first frequency domain unit configuration may be, for example, included in a CSI configuration or in higher layer signaling (e.g., RRC configuration). Accordingly, the UE <NUM>, RX processor <NUM> or the controller/processor <NUM> executing the CSI component <NUM> and/or the FD restriction component <NUM> may provide means for receiving a first frequency domain unit configuration indicating a precoding matrix indicator granularity.

In block <NUM>, the method <NUM> includes receiving a second FD unit configuration indicating a first set of configured FD units for which to report CSI. In an aspect, for example, the UE <NUM>, the RX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the FD restriction component <NUM> to receive the second FD unit configuration indicating the first set of configured FD units for which to report CSI. For instance, the second FD unit configuration may be the bit mask <NUM>, <NUM>. As discussed above, the bit mask <NUM>, <NUM> may be on a per sub-band or per FD unit basis. The FD restriction component <NUM> may determine FD units corresponding to the indicated sub-bands if a per sub-band bit mask is used. In an aspect, receiving the second FD unit configuration may include receiving a value indicating a number of FD units per sub-band. The FD restriction component <NUM> may determine the first number of FD units based on a multiplication of the number of sub-bands and the value. The CSI component <NUM> may compute the CQI for a sub-band using all of the FD units associated with the sub-band. In another aspect, receiving the second FD unit configuration indicating the first set of configured FD units for which to report CSI may include receiving a configuration of a set of FD units as a bitmap, wherein the length of the bitmap is equal to the total number of FD units, a "<NUM>" value in the bitmap indicates the first set of configured FD units, and wherein a channel quality indicator for a sub-band is computed using all of the FD units associated with the sub-band. If a sub-band is associated with no FD units, the CSI component <NUM> may drop the CSI report, report an outdated CSI, or report out of range for the sub-band. If an FD unit is associated with no sub-band for CQI, the CSI component <NUM> may report no CQI value for the FD unit or report no PMI for the FD unit. Accordingly, the UE <NUM>, RX processor <NUM>, or the controller/processor <NUM> executing the CSI component <NUM> and/or the FD restriction component <NUM> may provide means for receiving a second FD unit configuration indicating a first set of configured FD units for which to report CSI.

In block <NUM>, the method <NUM> includes determining a first number of FD units based on the first FD unit configuration and the first set of configured FD units. In an aspect, for example, the UE <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the FD restriction component <NUM> to determine the first number of FD units based on the first FD unit configuration and the first set of configured FD units. For example, the first number of FD units may be the number of FD units spanned by the first set of configured FD units to be reported. For example, the number of FD units spanned by the first set of configured FD units to be reported may be determined by subtracting the index of the first FD unit in the set from the index of the last FD unit in the set and adding one. Accordingly, the UE <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM> executing the CSI component <NUM> and/or the FD restriction component <NUM> may provide means for determining a first number of FD units based on the first FD unit configuration and the first set of configured FD units.

In block <NUM>, the method <NUM> includes selecting a second number of FD units that is greater than or equal to the first number of FD units. In an aspect, for example, the UE <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the FD compression component <NUM> to select the second number of FD units that is greater than or equal to the first number of FD units. The second number of FD units may be used for frequency domain compression. For instance, the UE <NUM> may be configured with a set of defined frequency domain coefficient dimensions that may be used for efficient frequency domain compression. For example, the defined frequency domain coefficient dimensions may be multiples of <NUM>, <NUM>, or <NUM>. In an aspect, for example, potential defined frequency domain coefficient dimensions may include <NUM>, <NUM>, <NUM>, and <NUM> when the FD unit is a sub-band. Larger frequency domain coefficient dimensions may be used if smaller FD units are defined. The FD compression component <NUM> may select the minimum defined frequency domain coefficient dimension that is greater than or equal to the first number of FD units as the second number of FD units. Accordingly, the UE <NUM>, TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM> executing the CSI component <NUM> and/or the FD compression component <NUM> may provide means for selecting a second number of FD units that is greater than or equal to the first number of FD units.

In block <NUM>, the method <NUM> includes determining whether to transmit a CSI report based on whether the first number of FD units satisfies a first threshold value for configured FD units, or the second number of FD units satisfies a second threshold value for reported FD units, or the precoding matrix indicator granularity satisfies the FD unit threshold. In an aspect, for example, the UE <NUM>, TX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the threshold component <NUM> to determine whether to transmit a CSI report based on whether the first number of FD units satisfies a first threshold value for configured FD units, or the second number of FD units satisfies a second threshold value for reported FD units, or the precoding matrix indicator granularity satisfies the FD unit threshold. For instance, the threshold component <NUM> may compare the FD unit threshold to either of the first FD configuration or the second FD configuration to determine whether to report CSI using FD compression for the received FD configuration. That is, the thresholds may restrict the FD configurations where the UE <NUM> may use FD compression. Accordingly, the UE <NUM> may avoid reporting CSI using FD compression where doing so would be inefficient. In view of the foregoing, the UE <NUM>, TX processor <NUM> or the controller/processor <NUM> executing the CSI component <NUM> and/or the threshold component <NUM> may provide means for determining whether to transmit a CSI report.

In block <NUM>, the method <NUM> may optionally include dropping the channel state information report. In an aspect, for example, the UE <NUM>, TX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the threshold component <NUM> to drop the channel state information report in response to one of the first FD configuration or the second FD configuration satisfying the FD unit threshold. For example, the threshold component <NUM> may drop the channel state information report in response to the received precoding matrix indicator granularity being less than the minimum number of resource blocks, in response to the first number of FD units being greater than a maximum number of FD units, or in response to the second number of FD units being greater than a maximum number of reported FD units. Accordingly, the UE <NUM>, TX processor <NUM>, or the controller/processor <NUM> executing the CSI component <NUM> and/or the threshold component <NUM> may provide means for dropping the channel state information report.

In block <NUM>, the method <NUM> may optionally include transmitting an outdated channel state information report. In an aspect, for example, the UE <NUM>, TX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the threshold component <NUM> to transmit a previous channel state information report in response to one of the first FD configuration or the second FD configuration satisfying the FD unit threshold. An outdated channel state report may be a CSI report that is not updated. For example, an outdated CSI report may be a previous CSI report, or a CSI report including meaningless information. In an aspect, the threshold component <NUM> may transmit an outdated channel state information report in response to the received precoding matrix indicator granularity being less than the minimum number of resource blocks, in response to the first number of FD units being greater than a maximum number of FD units, or in response to the second number of FD units being greater than a maximum number of reported FD units. Accordingly, the UE <NUM>, TX processor <NUM>, or the controller/processor <NUM> executing the CSI component <NUM> and/or the threshold component <NUM> may provide means for transmitting an outdated channel state information report.

In block <NUM>, the method <NUM> may optionally include transmitting a channel state information report for a maximum number of frequency domain units according to the FD unit threshold. In an aspect, for example, the UE <NUM>, TX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the threshold component <NUM> to transmit a channel state information report for a maximum number of frequency domain units according to the FD unit threshold in response to the second FD unit configuration satisfying the FD unit threshold. For example, the threshold component <NUM> may transmit a previous channel state information report in response to the first number of FD units being greater than a maximum number of FD units, or in response to the second number of FD units being greater than a maximum number of reported FD units. Accordingly, the UE <NUM>, TX processor <NUM>, or the controller/processor <NUM> executing the CSI component <NUM> and/or the threshold component <NUM> may provide means for transmitting a channel state information report for a maximum number of frequency domain units according to the FD unit threshold.

In block <NUM>, the method <NUM> may optionally include transmitting a channel state information report without frequency domain compression. In an aspect, for example, the UE <NUM>, TX processor <NUM>, or the controller/processor <NUM> may execute the CSI component <NUM> and/or the threshold component <NUM> to transmit the channel state information report without frequency domain compression in response to the first number of FD units being less than the minimum number of FD units. The threshold component <NUM> may fall back to a release <NUM> CSI report without FD compression because the FD compression may not reduce the size of the CSI report for a small number of FD units. Accordingly, the UE <NUM>, TX processor <NUM>, or the controller/processor <NUM> executing the CSI component <NUM> and/or the threshold component <NUM> may provide means for transmitting a channel state information report without frequency domain compression.

Referring to <FIG>, one example of an implementation of UE <NUM> may include a variety of components, some of which have already been described above, but including components such as one or more processors <NUM> and memory <NUM> and transceiver <NUM> in communication via one or more buses <NUM>, which may operate in conjunction with modem <NUM>, and CSI component <NUM> to enable one or more of the functions described herein related to activation of multiple SPS configurations and receiving PDSCH according to one the multiple SPS configurations. Further, the one or more processors <NUM>, modem <NUM>, memory <NUM>, transceiver <NUM>, RF front end <NUM> and one or more antennas <NUM> may be configured to support voice and/or data calls (simultaneously or non-simultaneously) in one or more radio access technologies.

In an aspect, the one or more processors <NUM> may include a modem <NUM> that uses one or more modem processors. The various functions related to CSI component <NUM> may be included in modem <NUM> and/or processors <NUM> and, in an aspect, may be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors <NUM> may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiver processor, or a transceiver processor associated with transceiver <NUM>. In other aspects, some of the features of the one or more processors <NUM> and/or modem <NUM> associated with CSI component <NUM> may be performed by transceiver <NUM>.

Also, memory <NUM> may be configured to store data used herein and/or local versions of applications <NUM>, CSI component <NUM> and/or one or more of subcomponents thereof being executed by at least one processor <NUM>. Memory <NUM> may include any type of computer-readable medium usable by a computer or at least one processor <NUM>, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory <NUM> may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining CSI component <NUM> and/or one or more of subcomponents thereof, and/or data associated therewith, when UE <NUM> is operating at least one processor <NUM> to execute CSI component <NUM> and/or one or more subcomponents thereof.

Receiver <NUM> may include hardware, firmware, and/or software code executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). Additionally, receiver <NUM> may process such received signals, and also may obtain measurements of the signals, such as, but not limited to, Ec/Io, SNR, RSRP, RSSI, etc. Transmitter <NUM> may include hardware, firmware, and/or software code executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium).

RF front end <NUM> may be connected to one or more antennas <NUM> and may include one or more low-noise amplifiers (LNAs) <NUM>, one or more switches <NUM>, one or more power amplifiers (PAs) <NUM>, and one or more filters <NUM> for transmitting and receiving RF signals.

In an aspect, LNA <NUM> may amplify a received signal at a desired output level.

Also, for example, one or more filters <NUM> may be used by RF front end <NUM> to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, a respective filter <NUM> may be used to filter an output from a respective PA <NUM> to produce an output signal for transmission. In an aspect, each filter <NUM> may be connected to a specific LNA <NUM> and/or PA <NUM>. In an aspect, RF front end <NUM> may use one or more switches <NUM> to select a transmit or receive path using a specified filter <NUM>, LNA <NUM>, and/or PA <NUM>, based on a configuration as specified by transceiver <NUM> and/or processor <NUM>.

In an aspect, transceiver <NUM> may be tuned to operate at specified frequencies such that UE <NUM> can communicate with, for example, one or more base stations <NUM> or one or more cells associated with one or more base stations <NUM>. In an aspect, for example, modem <NUM> may configure transceiver <NUM> to operate at a specified frequency and power level based on the UE configuration of the UE <NUM> and the communication protocol used by modem <NUM>.

In an aspect, modem <NUM> may be a multiband-multimode modem, which can process digital data and communicate with transceiver <NUM> such that the digital data is sent and received using transceiver <NUM>. In an aspect, modem <NUM> may be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, modem <NUM> may be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, modem <NUM> may control one or more components of UE <NUM> (e.g., RF front end <NUM>, transceiver <NUM>) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In an aspect, the modem configuration may be based on the mode of the modem and the frequency band in use. In another aspect, the modem configuration may be based on UE configuration information associated with UE <NUM> as provided by the network during cell selection and/or cell reselection.

Referring to <FIG>, one example of an implementation of a base station <NUM> may include a variety of components, some of which have already been described above, but including components such as one or more processors <NUM> and memory <NUM> and transceiver <NUM> in communication via one or more buses <NUM>, which may operate in conjunction with modem <NUM> and communications component <NUM> to enable one or more of the functions described herein related to CSI reporting using FD compression.

Claim 1:
A method of wireless communication, comprising:
receiving (<NUM>) a first frequency domain, FD, unit configuration indicating a precoding matrix indicator, PMI, granularity;
receiving (<NUM>) a second FD unit configuration indicating a first set of configured FD units for which to report channel state information, CSI;
determining (<NUM>) a first number of FD units based on the first FD unit configuration and the first set of configured FD units;
selecting (<NUM>) a second number of FD units that is greater than or equal to the first number of FD units; and
determining (<NUM>) whether to transmit a CSI report based on whether the first number of FD units satisfies a first threshold value for configured FD units, or the second number of FD units satisfies a second threshold value for reported FD units, or the PMI granularity satisfies a FD unit threshold based on a configured bandwidth part size.