Signaling for Enhancing CSI Feedback of Type II NR

Abstract

A method is provided for reporting channel state information (CSI) from a wireless device to a radio network node. More specifically, the wireless device receives an indication from the radio network node indicating a subset of frequency-domain (FD) basis vectors among a complete set of FD basis vectors. Accordingly, the wireless device uses the indicated subset of FD basis vectors to calculate CSI corresponding to an enhanced Type II port selection codebook and reports the CSI to the radio network node. The method disclosed herein enables reducing the complexity and signaling overhead for reporting CSI based on the selected subset of FD basis vectors.

Description

Technical Field

[0001] <Related Applications> This application claims the benefit of U.S. Provisional Patent Application No. 63 / 050,550, filed Jul. 10, 2020, the disclosure of which is hereby incorporated by reference in its entirety.

[0002] <Technical Field> The technology of the present disclosure generally relates to signaling for frequency and spatial domain basis indication to assist enhanced (enhanced) New Radio (NR) type II channel state information (CSI) feedback using reciprocity (reciprocity) of angles and delays.

Background Art

[0003] <Codebook-Based Precoding> Multi-antenna technology can significantly increase the data rate and reliability of wireless communication systems. When both the transmitter and the receiver are equipped with multiple antennas, the performance is particularly improved, resulting in a multiple-input multiple-output (MIMO) communication channel. Such systems and / or related techniques are generally referred to as MIMO.

[0004] The NR standard is currently evolving with support for enhanced MIMO. The core components in NR are the deployment of MIMO antennas and the support for MIMO-related technologies such as spatial multiplexing. The spatial multiplexing mode aims for high data rates in good channel conditions. A diagram of the spatial multiplexing operation is shown in FIG. 1.

[0005] As shown in the figure, the information carrying the symbol vector s is multiplied by an N T ×r precoder matrix W, which is (N TIt functions to distribute the transmission energy in a subspace of the ()-dimensional vector space corresponding to the individual antenna ports. The precoder matrix is typically selected from a codebook of precoder matrices that are considered, and is typically indicated by a precoder matrix indicator (PMI) that specifies a unique precoder matrix in the codebook for a given number of symbol streams. Each of the r symbols in s corresponds to a layer, and r is called the transmission rank. In this way, spatial multiplexing is achieved because multiple symbols can be transmitted simultaneously via the same time / frequency resource element (TFRE). The number of symbols r is typically adapted to fit the current channel characteristics.

[0006] NR uses orthogonal frequency division multiplexing (OFDM) in the downlink (and DFT-precoded OFDM in the uplink for rank-1 transmission), and thus the received N for a certain TFRE (or alternatively the number of data TFREs n) on subcarrier n R ×1 vector y n is TIFF0007695965000001.tif1152

[0007] Here, e n is the noise / interference vector obtained as an instance of a random process. The precoder W can be a wideband precoder that is constant over frequency or frequency selective.

[0008] The precoder matrix W is often R ×N T selected to match the characteristics of the MIMO channel matrix H of size n resulting in so-called channel-dependent precoding. This is generally also called closed-loop precoding and essentially attempts to concentrate the transmission energy in the strong subspaces in the sense of transmitting most of the transmission energy to the UE.

[0009] For closed-loop precoding for the NR downlink, the UE sends to the gNB a recommendation of the appropriate precoder to be used, based on channel measurements in the downlink. The gNB configures the UE to provide feedback according to CSI-ReportConfig, transmits channel state information (CSI) reference signals (RSs) (CSI-RSs), and may configure the UE to use the measured values of the CSI-RSs for feedback of the recommended precoding matrix selected by the UE from the codebook. It is possible to feedback a single precoder (wideband precoding) assumed to cover a wide bandwidth. It may also be beneficial to match the frequency variations of the channel and instead feedback one frequency-selective precoding report (e.g., several precoders) per subband. This is an example of a more general case of CSI feedback and also includes feedback of other information for recommending precoders to assist the gNodeB in subsequent transmissions to the UE. Such other information may include a channel quality indicator (CQI) as well as a transmission rank indicator (RI). In NR, CSI feedback can be either wideband where one CSI is reported for the entire channel bandwidth or frequency-selective where one CSI is reported per subband. Here, a subband is defined as the number of consecutive resource blocks between 4 and 32 PRBs, depending on the bandwidth part (BWP) size.

[0010] Given the CSI feedback from the UE, the gNB determines the transmission parameters it wishes to use for transmitting to the UE, including the precoding matrix, transmission rank, and modulation and coding scheme (MCS). These transmission parameters may differ from the recommendations made by the UE. The transmission rank, and thus the number of spatial multiplexing layers, is reflected in the number of columns of the precoder W. For efficient performance, it is important that a transmission rank matching the channel characteristics is selected.

[0011] 2D antenna array The disclosed teachings can be used with a two-dimensional antenna array, and some of the disclosed embodiments use such an antenna array. Such an antenna array can be (partially) described by the number N of antenna columns corresponding to the horizontal dimension h , the number N of antenna rows corresponding to the vertical dimension v , and the number N of dimensions corresponding to different polarization states p . Thus, the total number of antennas is N h N v N p . It should be noted that the concept of an antenna is non-limiting in the sense that it can refer to any virtualization (e.g., a linear mapping) of physical antenna elements. For example, a pair of physical sub-elements can be fed the same signal and thus share the same virtual antenna port.

[0012] An example of a 4x4 array with dual-polarization antenna elements is shown in FIG. 2.

[0013] Precoding can be interpreted as multiplying the signal for each antenna with a different beamforming weight before transmission. A typical approach is, for example, to take into account N h , N v , and N p when designing the precoder codebook and to match the precoder to the antenna form factor.

[0014] Channel State Information Reference Signal (CSI-RS) For CSI measurement and feedback, CSI-RS is defined. CSI-RS is transmitted on each antenna port and is used by a user equipment (UE) to measure the downlink channel between each of the transmit antenna ports and each of the receive antenna ports in the UE. The transmit antenna ports are also called CSI-RS ports. The number of antenna ports supported in NR is {1, 2, 4, 8, 12, 16, 24, 32}. By measuring the received CSI-RS, the UE can estimate the channel that the CSI-RS traverses, including the radio propagation channel and the antenna gain. CSI-RS for the above purposes is also called non-zero power (NZP) CSI-RS.

[0015] CSI-RS can be configured to be transmitted in a slot and in specific resource elements (REs) within a specific slot in the slot. FIG. 3 shows an example of CSI-RS REs for 12 antenna ports, with 1 RE shown for each RB per port.

[0016] Also, interference measurement resources (IMRs) are defined in NR for the UE to measure interference. The IMR resource includes either four adjacent REs in the frequency within the same OFDM symbol, or four REs of any of the 2×2 adjacent REs in both time and frequency within a slot. By measuring both the channel based on NZP CSI-RS and the interference based on IMR, the UE can estimate the effective channel and the noise plus interference to determine CSI (e.g., rank, precoding matrix, and channel quality).

[0017] Furthermore, a UE within NR can be configured to measure interference based on one or more NZP CSI-RS resources.

[0018] CSI Framework in NR In NR, a UE can be configured using multiple CSI report settings and multiple CSI-RS resource settings. Each resource setting can include multiple resource sets, and each resource set can include up to 8 CSI-RS resources. For each CSI report setting, the UE feeds back a CSI report.

[0019] Each CSI report setting includes at least the following information. · CSI-RS resource sets for channel measurement · IMR resource sets for interference measurement · Optionally, CSI-RS resource sets for interference measurement · Time-domain behavior, i.e., periodic, semi-persistent, or aperiodic reporting · Frequency granularity, i.e., wideband or sub-band · Reported CSI parameters such as RI, PMI, CQI, and CSI-RS resource indicator (CRI) in the case of multiple CSI-RS resources within a resource set · Codebook type, i.e., type I or II, and restrictions on codebook subsets · Measurement restrictions · Sub-band size. One of two possible sub-band sizes is indicated, and the value range depends on the bandwidth of the BWP. One CQI / PMI (if configured for sub-band reporting) is fed back per sub-band.

[0020] When the CSI-RS resource set within a CSI report setting includes multiple CSI-RS resources, one of the CSI-RS resources is selected by the UE, and the CRI is also reported by the UE to indicate to the gNB, together with the RI, PMI, and CQI associated with the selected CSI-RS resource, for the selected CSI-RS resource within the resource set.

[0021] In the case of aperiodic CSI reporting in NR, two or more CSI report configurations each having a different CSI-RS resource set for channel measurement and / or a resource set for interference measurement are configured and can be triggered at the same time. In this case, multiple CSI reports are aggregated and transmitted from the UE to the gNB on a single Physical Uplink Shared Channel (PUSCH).

[0022] Enhanced Type II Port Selection Codebook for NR Release 16 The enhanced type II (eType II) port selection (PS) codebook is introduced in Release (Rel-) 16 and is intended to be used for beamformed CSI-RS. Each CSI-RS port covers a small part of the cell coverage area with a high beamforming gain (compared to non-beamformed CSI-RS). Although the implementation of the gNB has been reached, usually each CSI-RS port is assumed to be transmitted with a 2D spatial beam having a main lobe with an azimuth pointing angle and an elevation pointing angle. The actual precoder matrix used for CSI-RS is transparent to the UE. Based on the measurement, the UE selects the best CSI-RS port and recommends to the gNB to use it for DL transmission. The eType II PS codebook can be used by the UE to feedback the selected CSI-RS port and as a method to combine the selected CSI-RS ports. The configured CSI-RS ports can be regarded as a spatial domain (SD)-based set, and the SD-based subset is determined and reported by the UE.

[0023] Structure, Configuration, and Reporting of eType II PS Codebook For a given transmit layer l, TIFF0007695965000002.tif1132 and v for RI, the precoder matrix for all frequency domain (FD) units has size P CSI-RS × N3 (i.e., P CSI-RS rows and N3 columns) matrix W lis given by, where ·P CSI-RS is the number of single-polarization CSI-RS ports. ·N3 = N SB ×R is the number of PMI sub-bands, and ·The value R = {1, 2} (indicator of PMI sub-band size) is configured by RRC. ·N SB is the number of CQI sub-bands and is configured by RRC. ·The RI value v is set according to the configured upper layer parameter typeII-RI-Restriction-r16. The UE does not report v > 4.

[0024] The precoder matrix W l is factorized as TIFF0007695965000003.tif1346, and W l is normalized as TIFF0007695965000004.tif1339 for l = 1, …, v. TIFF0007695965000004.tif1339

[0025] The port selection matrix W1: W1 is a port selection precoder matrix of size P CSI-RS ×2L, which can be factorized as TIFF0007695965000005.tif1350, ·W PS is a port selection matrix of size P CSI-RS / 2×L composed of 0 and 1. The selected ports are indicated by 1 which is common for both polarizations. ·L is the number of CSI-RS ports selected for each polarization. The supported values of L are in Table 1. ·The selected CSI-RS ports are jointly determined by two parameters d and i 1,l Starting from the i 1,l -th port, only every d-th port can be selected (the port numbering is determined by the gNB). · The value of d is composed of the upper layer parameter portSelectionSamplingSize, where TIFF0007695965000006.tif1237 and d < min(P CSI-RS / 2, L). · i 1,l 's value, where TIFF0007695965000007.tif1469, is determined by the UE based on CSI-RS measurements. The UE feeds back the selected i 1,l to the gNB. · W1 is common to all layers.

[0026] The compression matrix W in the frequency domain f,l :W f,l is the compression matrix in the FD domain of size N3×M for layer l, where v · · TIFF0007695965000008.tif1534 is the number of selected FD basis vectors, which depends on the rank indicator v and the RRC-configured parameter p v . The supported values of p v are in Table 1. · TIFF0007695965000009.tif1364, where TIFF0007695965000010.tif1526 are N3 orthogonal DFT basis vectors of size N3×1 TIFF0007695965000011.tif1323 from which M v FD basis vectors of size N3×1 are selected. · For N3 ≤ 19, for example, one-step free selection is used. · For each layer, the FD basis selection is indicated by TIFF0007695965000012.tif1741 a bit combination indicator. In TS 38.214, the combination indicator is the index i 1,6,lis given, where l corresponds to the layer index. This combined index is reported by the UE to the gNB for each layer for each PMI. · For N3 > 19, two-step selection with a layer-common intermediate subset (IntS) is used. · In this first step, window-based layer-common IntS selection is used, which is parameterized by initial M. The IntS includes FD basis vectors mod(M initial +n, N3), where TIFF0007695965000013.tif1143 and TIFF0007695965000014.tif109 = 2M v is. In TS 38.214, the selected IntS is reported by the UE to the gNB via the parameter i 1,5 as part of the PMI. · The second step subset selection is indicated by a 1640-bit combined indicator for each layer in part 2 of the CSI report. In TS 38.214, the combined indicator is given by the index i TIFF0007695965000015.tif1640, where l corresponds to the layer index. This combined index is reported by the UE to the gNB for each layer for each PMI. 1,6,l is given, where l corresponds to the layer index. This combined index is reported by the UE to the gNB for each layer for each PMI. · W f,l is layer-specific.

[0027] Linear combination coefficient matrix TIFF0007695965000016.tif1012: · TIFF0007695965000017.tif1012 is a 2L × M v matrix containing 2LM v coefficients for linearly combining the selected M v FD basis vectors for the selected 2L CSI-RS ports. · For layer l, Only the subset of coefficients of TIFF0007695965000018.tif1026 that are non - zero are reported. The remaining The unreported coefficients of TIFF0007695965000019.tif1134 are considered zero. · TIFF0007695965000020.tif1244 is the maximum number of non - zero coefficients per layer, where β is the RRC configuration parameter. The supported values of β are shown in Table 1. · In the case of TIFF0007695965000021.tif1130, the total number of non - zero coefficients summed over all layers TIFF0007695965000022.tif1142 is TIFF0007695965000023.tif1129 is assumed to be satisfied. · The selected coefficient subset for each layer is indicated by 1s in a bitmap of size 2LM v that is included in part 2 of the CSI report TIFF0007695965000024.tif1113. · An indication of TIFF0007695965000025.tif1011, where TIFF0007695965000026.tif1151, is included in part of the CSI report so that the payload of part 2 of the CSI report can be known. · The amplitude and phase of the coefficients in TIFF0007695965000027.tif1012 are assumed to be quantized for reporting. · TIFF0007695965000028.tif1012 is layer - specific. TIFF0007695965000029.tif59127

[0028] FDD - based Inter - operation In frequency division duplex (FDD) operation, uplink (UL) and downlink (DL) transmissions are performed on different frequencies, and thus, the propagation channels during UL and DL are not reciprocal as in the case of time division duplex (TDD). Nevertheless, some physical channel parameters, such as the delay and angle for different clusters that depend on the spatial characteristics of the channel but not on the carrier frequency, are reciprocal between UL and DL. Such characteristics can be utilized to obtain FDD transmission based on partial reciprocity. The reciprocal part of the channel can be combined with the non-reciprocal part to obtain the complete channel. The estimated value of the non-reciprocal part can be obtained by feedback from the UE.

[0029] One procedure for a reciprocity-based FDD transmission scheme is shown in FIG. 4 in four steps, assuming that the enhanced type II port selection codebook of NR Release 16 is used.

[0030] In step 1, the UE transmits SRS in UL for the gNB to estimate the angles and delays of different clusters associated with different propagation paths, where the UE is configured by the gNB with SRS.

[0031] In step 2, in the algorithm implemented by the gNB, the gNB selects the dominant cluster according to the estimated angle-delay power spectrum profile, and for each of the selected clusters, the gNB selects gNB precoding (e.g., beamforming), and transmits one CSI-RS port for each polarization to the UE according to the obtained angle and / or delay estimation.

[0032] In step 3, the gNB configures the UE to measure CSI-RS, and the UE measures the received CSI-RS ports and then determines type II CSI including RI, the PMI for each layer, and CQI. The precoding matrix indicated by the PMI includes the selected beam (e.g., the precoded CSI-RS port) and the corresponding best phase and amplitude for aligning the selected beam. The phase and amplitude of each beam are quantized and fed back to the gNB.

[0033] In step 4, the algorithm implemented by the gNB calculates the DL precoding matrix for each layer based on the selected beam and the feedback of the corresponding amplitude and phase, and performs physical downlink shared channel (PDSCH) transmission. The transmission is directly based on the feedback (PMI) precoding matrix (e.g., SU-MIMO transmission), or the transmission precoding matrix is obtained from an algorithm (MU-MIMO transmission) that combines CSI feedback from multiple UEs. In this case, the precoder is derived based on the precoding matrix (e.g., zero-forcing precoder or normalized ZF precoder) including CSI reports from simultaneously scheduled UEs. The final precoder is generally scaled so that the transmission power for each power amplifier is not overridden.

[0034] Such reciprocity-based transmission can potentially be utilized in codebook-based DL transmission for FDD, for example, to reduce the feedback overhead in UL when the NR type II port selection codebook is used. Another potential advantage is the reduction in complexity in CSI calculation at the UE.

[0035] Type II port selection codebook for FDD operation based on angle / delay reciprocity If the enhanced type II port selection codebook in Release 16 is used for FDD operation based on angle and / or delay reciprocity, FD base Wf still needs to be determined by the UE. Therefore, in the CSI report, the feedback overhead for indicating which FD basis W f is selected can increase, especially when N3, the number of PMI sub-bands, is large. Also, the computational complexity for evaluating and selecting the best FD basis increases as N3 increases.

[0036] In the methods proposed outside the scope of the present disclosure, in terms of the reciprocity of the delay between UL and DL, the gNB uses the estimated delay information for the cluster selected in UL to pre-determine a subset of the FD basis TIFF0007695965000030.tif1111. Then, the gNB can indicate to the UE about this pre-determined subset of the FD basis TIFF0007695965000031.tif1111. Then, the UE can evaluate and select the FD basis vectors within the pre-determined subset.

[0037] In the methods proposed outside the scope of the present disclosure, the gNB analyzes the angle-delay power spectrum of the channel to determine the angles and delays of different clusters. For example, the left part of FIG. 5's 8×10 grid shows the angle-delay power spectrum of the UL channel with 8 angle bins and 10 delay taps, and each shaded square represents the power level of a given cluster at a certain angle and delay. Based on the reciprocity of the angles, the gNB selects the two strongest clusters in this example and precodes one CSI-RS port for each polarization for transmission to each cluster (i.e., a total of 4 CSI-RS ports). In the right part of FIG. 5, the two beamformed channels (i.e., the two beamformed channels correspond to the two selected clusters) have only 4 taps in the delay region, while the original channel has 10 taps. Therefore, the four vectors It can be converted to an FD basis having TIFF0007695965000032.tif1353, and the remaining four delay taps can be transmitted from the gNB to the UE. As a result, the UE only needs to select the best frequency basis vector from four FD basis vector candidates instead of ten. Therefore, in this example, the overhead for indicating which FD basis is selected can be reduced, and the complexity of the operations in the UE for selecting the best FD basis can be reduced.

[0038] In another method proposed outside the scope of the present disclosure, the gNB pre-compensates the delay for each beamformed channel so that the strongest paths in all beamformed channels arrive at the UE simultaneously. As can be seen in FIG. 6, after pre-compensating the delay of the beamformed channels, the number of delay taps is reduced to 3 in the two beamformed channels corresponding to the two selected clusters. This is in contrast to the 10 delay taps in the raw channel. Further, since the 0th delay component (corresponding to the 0th FD basis vector, i.e., the DC basis) always exists, the gNB only needs to signal TIFF0007695965000033.tif1239 to the UE. Therefore, the UE only needs to select the best frequency basis vector from two FD basis vector candidates instead of four as in the example of FIG. 5. Therefore, in this example, not only is the overhead for indicating which FD component is selected reduced, but the overhead in reporting the corresponding LC coefficients from the UE to the gNB can also be reduced. Further, the complexity of the calculations in the UE for selecting the best FD basis can be reduced. It can be converted to an FD basis having TIFF0007695965000033.tif1239, and the remaining four delay taps can be transmitted from the gNB to the UE. As a result, the UE only needs to select the best frequency basis vector from four FD basis vector candidates instead of ten. Therefore, in this example, the overhead for indicating which FD basis is selected can be reduced, and the complexity of the operations in the UE for selecting the best FD basis can be reduced.

[0039] Therefore, the solutions proposed above can be used to reduce the overhead of CSI feedback for indicating which FD basis vectors are used, as well as the corresponding phases and amplitudes for combining the selected FD basis and SD basis. The solutions proposed above also reduce the computational complexity for the UE to select the best FD basis vectors.

SUMMARY OF THE INVENTION

[0040] Embodiments disclosed herein include a method for reporting channel state information (CSI) from a wireless device to a wireless network node. More specifically, a wireless device receives an indication from a wireless network node indicating a subset of FD basis vectors from a complete set of FD basis vectors in the frequency domain (FD). Accordingly, the wireless device uses the indicated subset of FD basis vectors to calculate CSI corresponding to an extended type II port selection codebook and reports the CSI to the wireless network node. The method disclosed herein makes it possible to reduce the complexity and signaling overhead for reporting CSI based on a selected subset of FD basis vectors.

[0041] In one aspect, a method performed by a wireless device for reporting CSI is provided. The method includes receiving, from a wireless network node, an indication indicating a subset of FD basis vectors from a complete set of FD basis vectors for each group of transmission layers. The method also includes calculating CSI corresponding to an extended type II port selection codebook using the indicated subset of FD basis vectors. The method also includes reporting the CSI to the wireless network node.

[0042] In another aspect, the complete set of FD basis vectors comprises a set of orthogonal complex vectors having a length equal to N3.

[0043] In another aspect, N3 is determined by the upper layer parameters numberOfPMISubbandsPerCQISubband and csi-ReportingBand.

[0044] In another aspect, receiving an indication indicating a subset of FD basis vectors comprises receiving an indication indicating a selected subset of FD basis vectors in a control message.

[0045] In another aspect, the control message is a media access control (MAC) control element (CE).

[0046] In another aspect, the MAC CE comprises a field configured to indicate a subset of FD basis vectors out of a complete set of FD basis vectors.

[0047] In another aspect, the field in the MAC CE is one of an N3-bit bitmap or TIFF0007695965000034.tif an 1129-bit bitmap.

[0048] In another aspect, the MAC CE comprises a plurality of fields each configured to indicate a subset of FD basis vectors out of a complete set of FD basis vectors for each one of a plurality of layers.

[0049] In another aspect, each of the plurality of fields in the MAC CE is one of an N3-bit bitmap or TIFF0007695965000035.tif an 1129-bit bitmap.

[0050] In another aspect, receiving an indication indicating a subset of FD basis vectors includes receiving an indication indicating a subset of FD basis vectors in downlink control information (DCI).

[0051] In another aspect, the DCI includes a field configured to correspond to a code point and indicate a subset of FD basis vectors within a complete set of FD basis vectors.

[0052] In another aspect, the field in the DCI includes CSI-AssociatedReportConfigInfo corresponding to a code point.

[0053] In another aspect, the method also includes receiving from a radio network node a configuration of a CSI reference signal (CSI-RS) resource having a set of CSI-RS ports and an indication indicating one or more of the one or more non-zero power CSI-RS ports and one or more zero power CSI-RS ports. The method also includes performing channel measurements on the one or more non-zero power CSI-RS ports.

[0054] In another aspect, calculating the CSI using the indicated subset of FD basis vectors comprises calculating the CSI based on all of the indicated subset of FD basis vectors. Reporting the CSI includes not reporting an index indicating a subset of the indicated subset of FD basis vectors as part of an enhanced type II port selection precoding matrix indicator (PMI) report.

[0055] In another aspect, calculating the CSI using the indicated subset of FD basis vectors comprises calculating the CSI based on a subset selected from the indicated subset of FD basis vectors. Reporting the CSI includes reporting an index indicating the selected subset of the indicated subset of FD basis vectors as part of an enhanced type II port selection precoding matrix indicator (PMI) report.

[0056] In one aspect, a wireless device is provided. The wireless device includes a processing circuit. The processing circuit is configured to cause the wireless device to receive, from a wireless network node, an indication indicating a subset of FD basis vectors from a complete set of FD basis vectors for each group of transmission layers. The processing circuit is also configured to cause the wireless device to calculate, using the indicated FD basis vectors, a CSI corresponding to an enhanced type II port selection codebook. The processing circuit is also configured to cause the wireless device to report the CSI to the wireless network node.

[0057] In another aspect, a processing circuit is configured to cause the wireless device to execute any of the steps in any of the claims executed by the wireless device.

[0058] In one aspect, a method performed by a wireless network node to enable a wireless device to report CSI is provided. The method includes providing, to the wireless device, an indication indicating a subset of FD basis vectors from a complete set of FD basis vectors for each group of transmission layers. The method also includes receiving CSI from the wireless device.

[0059] In another aspect, the method also includes determining, based on one or more uplink measurement values performed on a sounding reference signal (SRS) received from the wireless device, a subset of FD basis vectors from a complete set of FD basis vectors.

[0060] In another aspect, providing an indication indicating a subset of FD basis vectors comprises indicating a selected subset of FD basis vectors in a control message.

[0061] In another aspect, the control is a MAC CE.

[0062] In another aspect, the MAC CE has a field configured to indicate a subset of the FD basis vectors within a complete set of FD basis vectors.

[0063] In another aspect, a field within the MAC CE comprises one of an N3-bit bitmap or TIFF0007695965000036.tif a 1129-bit bitmap.

[0064] In another aspect, the MAC CE comprises a plurality of fields each configured to indicate a subset of the FD basis vectors within a complete set of FD basis vectors for each of a plurality of layers.

[0065] In another aspect, each of the plurality of fields in the MAC CE comprises one of an N3-bit bitmap or TIFF0007695965000037.tif a 1129-bit bitmap.

[0066] In another aspect, providing an indication of a subset of the FD basis vectors comprises providing an indication of a subset of the FD basis vectors in the DCI.

[0067] In another aspect, the DCI corresponds to a code point and includes a field configured to indicate a subset of the FD basis vectors within a complete set of FD basis vectors.

[0068] In another aspect, a field in the DCI includes CSI-AssociatedReportConfigInfo corresponding to the code point.

[0069] In another aspect, the method also includes configuring a set of CSI-RS resources having a set of CSI-RS resources and providing to the wireless device an indication indicating one or more non-zero power CSI-RS ports in the CSI-RS resources and / or one or more zero power CSI-RS ports in the CSI-RS resources. The method also includes receiving from the wireless device channel measurement values performed based on the one or more non-zero power CSI-RS ports.

[0070] In another aspect, receiving CSI includes receiving CSI that does not include an index indicating a subset of a shown subset of FD basis vectors as part of an enhanced type II port selection PMI report, and receiving CSI that includes an index indicating a selected subset of a shown subset of FD basis vectors as part of an enhanced type II port selection PMI report, including one of them.

[0071] In one aspect, the wireless network node comprises a processing circuit. The processing circuit is configured to cause the wireless network node to provide to the wireless device an indication indicating a subset of FD basis vectors in a complete set of FD basis vectors for each group of transmission layers. The processing circuit is also configured to cause the wireless network node to receive CSI from the wireless device.

[0072] In another aspect, the processing circuit is further configured to cause the wireless network node to execute any of the steps in any of the claims performed by the wireless access node.

Brief Description of the Drawings

[0073] The accompanying drawings, which are incorporated herein and form a part of this specification, illustrate some aspects of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

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DETAILED DESCRIPTION OF THE INVENTION

[0098] The embodiments described below represent information for enabling those skilled in the art to implement the embodiments and exemplify the best mode of implementing the embodiments. Reading the following description in light of the accompanying drawings, those skilled in the art will understand the concepts of the present disclosure and recognize the application of these concepts that are not specifically addressed herein. It should be understood that these concepts and applications are within the scope of the present disclosure.

[0099] Wireless Node: As used herein, a "wireless node" is either a wireless access node or a wireless communication device.

[0100] Wireless Access Node: As used herein, a "wireless access node" or "wireless network node" or "wireless access network node" is any node within a radio access network (RAN) of a cellular communication network that operates to transmit and / or receive signals wirelessly. Some examples of wireless access nodes include, but are not limited to, base stations (e.g., a gNB in a 3rd Generation Partnership Project (3GPP (R)) 5th Generation (5G) New Radio (NR) network or an evolved or enhanced Node B (eNB) in a 3GPP (R) Long Term Evolution (LTE) network), high-power or macro base stations, low-power base stations (e.g., micro base stations, pico base stations, home eNBs, etc.), relay nodes, network nodes that implement part of the functions of a base station (e.g., a network node that implements a gNB Central Unit (gNB-CU) or a network node that implements a gNB Distributed Unit (gNB-DU)), or network nodes that implement part of the functions of some other type of wireless access node.

[0101] Core network node: As used herein, a "core network node" is any type of node within a core network or any node that implements core network functionality. Some examples of core network nodes include, for example, a Mobility Management Entity (MME), a Packet Data Network Gateway (P-GW), a Service Capability Exposure Function (SCEF), a Home Subscriber Server (HSS), etc. Some other examples of core network nodes include nodes that implement an Access and Mobility Management Function (AMF), a User Plane Function (UPF), a Session Management Function (SMF), an Authentication Server Function (AUSF), a Network Slice Selection Function (NSSF), a Network Exposure Function (NEF), a Network Function (NF) Repository Function (NRF), a Policy Control Function (PCF), a Unified Data Management (UDM), etc.

[0102] Communication device: As used herein, a "communication device" is any type of device having access to an access network. Some examples of communication devices include, but are not limited to, mobile phones, smartphones, sensor devices, meters, vehicles, home appliances, medical devices, media players, cameras, or any type of consumer electronics device, such as, but not limited to, a television, a radio, a lighting device, a tablet computer, a laptop, or a personal computer (PC). A communication device can be a portable, handheld, computer-integrated, or in-vehicle mobile terminal capable of communicating voice and / or data via a wireless or wired connection.

[0103] Wireless communication device: One type of communication device is a wireless communication device, which can be any type of wireless device that accesses (i.e., is served by) a wireless network (e.g., a cellular network). Some examples of wireless communication devices include, but are not limited to, user equipment devices (UE) in a 3GPP (registered trademark) network, machine type communication (MTC) devices, and Internet of Things (IoT) devices. Such wireless communication devices can be mobile phones, smartphones, sensor devices, meters, vehicles, household appliances, medical devices, media players, cameras, or any type of consumer electronics device, e.g., but not limited to, TVs, radios, lighting devices, tablet computers, laptops, or PCs, or can be integrated into them. A wireless communication device can be a portable, handheld, computer-integrated, or in-vehicle mobile terminal capable of communicating voice and / or data via a wireless connection.

[0104] Network node: As used herein, a "network node" is any node that is part of either the RAN or the core network of a cellular communication network / system.

[0105] The description given herein focuses on 3GPP (registered trademark) cellular communication systems, and thus it should be noted that 3GPP (registered trademark) terms or terms similar to 3GPP (registered trademark) terms are often used. However, the concepts disclosed herein are not limited to 3GPP (registered trademark) systems.

[0106] Although the term "cell" may be referred to in the description herein, with respect to the 5G NR concept in particular, beams may be used instead of cells, and thus it is important to note that the concepts described herein are equally applicable to both cells and beams.

[0107] Currently, there are certain problems. The problem of how to signal the base vectors in the selected frequency domain and / or the channel state indicator (CSI)-reference signal (RS) (CSI-RS) ports in the spatial domain from the gNB to the UE is not addressed. Further, signaling the selected subset of FD base vectors and / or CSI-RS ports can increase the downlink control overhead. In this regard, it may be desirable to efficiently signal the selected subset of FD base vectors and / or CSI-RS ports with minimal downlink control overhead while ensuring the reliability of the signaling.

[0108] Certain aspects of the present disclosure and their embodiments can provide solutions to the foregoing or other problems. In the present disclosure, a method for signaling, by a gNB to a UE, a selected subset of frequency domain (FD) base vectors from a complete set of FD base vectors and / or a selected subset of CSI-RS ports from a complete set of CSI-RS ports is proposed. Solutions based on both media access control (MAC) control element (CE) signaling and downlink control information (DCI) signaling are proposed to reduce the overhead associated with signaling a subset of FD base vectors and / or CSI-RS ports. Based on the proposed solution, a method for using all signaled subsets of FD base vectors and / or CSI-RS ports for a CSI report for an enhanced (i.e., Release 16) type II port selection codebook for the UE to reduce the complexity of the UE and the overhead of the CSI report is also proposed. A further method is also proposed in which the UE performs further FD base vector and / or CSI-RS port sub-selection based on the signaled subset of FD base vectors instead of the complete set of FD base vectors and / or the subset of CSI-RS ports, reducing the complexity of the UE.

[0109] Furthermore, a method for signaling the CSI-RS ports to be measured is also proposed, which can be signaled together with a selected subset of FD basis vectors. The specific embodiments disclosed herein include at least the following aspects. 1. A method for signaling, from a complete set N3 of FD basis vectors, a selected subset of FD basis vectors from a network to a UE, wherein the FD basis vectors are a set of orthogonal complex vectors having a length equal to N3, the method comprising: using the indicated FD basis vectors for the UE to calculate CSI corresponding to an enhanced type II port selection codebook. 2. The method of 1, wherein the selected subset of FD basis vectors is signaled via a MAC CE. 3. The method of 1 or 2, wherein each bit in a field of length N3 within the MAC CE indicates whether an FD basis vector is selected. 4. The method of any one of 1 to 3, wherein a maximum number of FD basis vectors can be selected and signaled in the MAC CE. 5. The method of 4, wherein the maximum number of FD basis vectors is determined via one or more upper layer configuration parameters. 6. The method of 1, wherein the selected subset of FD basis vectors is signaled via DCI. 7. The method of any one of 1 to 6, wherein the UE uses all the indicated FD basis vectors to calculate CSI. 8. The method of 7, wherein the UE does not feedback the indices i 1,5 and i 1,6,l as part of an enhanced type II port selection PMI report. 9. The method of any one of 1 to 6, wherein the UE uses a subset of the indicated FD basis vectors to calculate CSI. 10. The method of 9, wherein the UE, as part of an enhanced type II port selection PMI report, the index i 1,5and i 1,6,l One or more of them may be reported. 11. Any method from 1 to 10, wherein the gNB additionally indicates to the UE a subset of non-zero power CSI-RS ports among a set of configured CSI-RS ports for performing channel measurements. 12. Any method from 1 to 10, the method further including the gNB indicating zero power CSI-RS ports among a set of configured CSI-RS ports to the UE. 13. The method of 12, wherein the UE performs channel measurements on CSI-RS ports that are not indicated as zero power CSI-RS ports among the set of CSI-RS ports.

[0110] In this specification, various embodiments are proposed to address one or more of the problems disclosed in this specification.

[0111] In one embodiment, a method performed by a wireless device for reporting CSI is provided. The method includes receiving a selected subset of FD basis vectors from a full set of FD basis vectors (e.g., N3) from a network node (e.g., eNB). The method also includes using the selected subset of FD basis vectors to calculate CSI corresponding to an enhanced (e.g., Release 16) type II port selection codebook. The method also includes reporting the CSI to the network node.

[0112] In another embodiment, a method performed by a base station (e.g., eNB) to enable a wireless device to report CSI is provided. The method includes indicating to the wireless device a selected subset of FD basis vectors within a full set of FD basis vectors (e.g., N3). The method also includes receiving CSI from the wireless device.

[0113] Certain embodiments can provide one or more of the following technical advantages. The main advantages of the proposed solutions are as follows. ·Reduction of CSI report overhead ·Reduction of UE complexity ·Reduction of signaling overhead for indicating a selected subset of FD basis vectors

[0114] Figure 7 shows an example of a cellular communication system 700 in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communication system 700 is a 5G system (5GS) including a next-generation RAN (NG-RAN) and a 5G core (5GC). In this example, the RAN includes base stations 702-1 and 702-2, and in the 5GS, includes an NR base station (gNB) and optionally a next-generation eNB (ng-eNB) (e.g., an LTE RAN node connected to the 5GC), and controls corresponding (macrocell) cells 704-1 and 704-2. Base stations 702-1 and 702-2 are generally referred to collectively as base station 702 and individually as base station 702 herein. Similarly, (macrocell) cells 704-1 and 704-2 are generally referred to collectively as (macrocell) cell 704 and individually as (macrocell) cell 704 herein. The RAN may also include several low-power nodes 706-1 to 706-4 that control corresponding small cells 708-1 to 708-4. The low-power nodes 706-1 to 706-4 may be small base stations (such as pico or femto base stations) or remote radio heads (RRHs), etc. In particular, although not shown, one or more of the small cells 708-1 to 708-4 may alternatively be provided by the base station 702. The low-power nodes 706-1 to 706-4 are generally referred to collectively as low-power node 706 and individually as low-power node 706 herein. Similarly, the small cells 708-1 to 708-4 are generally referred to collectively as small cell 708 and individually as small cell 708 herein. The cellular communication system 700 also includes a core network 710, which is called 5GC in the 5G system (5GS). The base stations 702 (and optionally the low-power nodes 706) are connected to the core network 710.

[0115] The base station 702 and the low power node 706 provide services to the wireless communication devices 712-1 to 712-5 within the corresponding cells 704 and 708. The wireless communication devices 712-1 to 712-5 are generally collectively referred to herein as the wireless communication devices 712 and individually as the wireless communication device 712. In the following description, the wireless communication device 712 is often a UE, but the present disclosure is not limited thereto.

[0116] Before describing specific embodiments of the present disclosure, methods performed by wireless devices (e.g., 712-1, 712-2, 712-3) and methods performed by wireless network nodes (e.g., 702-1, 702-2, 706-1, 706-2, 706-3, 706-4) to enable specific embodiments are first given with reference to FIGS. 8 and 9.

[0117] FIG. 8 is a flowchart of an exemplary method performed by a wireless device for reporting CSI according to an embodiment of the present disclosure. The wireless device receives, from a wireless network node, an indication indicating a subset of FD basis vectors within a complete set of FD basis vectors for each group of transmission layers (step 800). In one embodiment, the wireless device may receive an indication indicating a subset of FD basis vectors in a control message (step 800-1). In another embodiment, the wireless device may receive an indication indicating a subset of FD basis vectors in DCI (step 800-2). The wireless device may receive, from the network node, a configuration of CSI-RS resources having a set of CSI-RS ports and an indication indicating one or more non-zero power CSI-RS ports in the CSI-RS resources and / or one or more zero power CSI-RS ports in the CSI-RS resources (step 802). Thus, the wireless device may perform channel measurements on one or more non-zero power CSI-RS ports (step 804). The wireless device uses the indicated subset of FD basis vectors to calculate CSI corresponding to an enhanced type II port selection codebook (step 806). In one embodiment, the wireless device can calculate CSI based on all of the indicated subset of FD basis vectors (step 806-1). In another embodiment, the wireless device may calculate CSI based on a selected subset of the indicated subset of FD basis vectors (step 806-2). The wireless device reports the CSI to the wireless network node (step 808). In one embodiment, the wireless device may not report an index indicating a subset of the indicated subset of FD basis vectors as part of an enhanced type II port selection precoding matrix indicator (PMI) report (step 808-1). In another embodiment, the wireless device may report an index indicating a selected subset of the indicated subset of FD basis vectors as part of an enhanced type II port selection PMI report (step 808-2).

[0118] Figure 9 is a flowchart of an exemplary method performed by a wireless network node to enable a wireless device to report CSI according to an embodiment of the present disclosure. The wireless network node can determine a subset of FD basis vectors from a full set of FD basis vectors based on one or more uplink measurements performed on SRS received from the wireless device (step 900). The wireless network node provides an indication indicating the subset of FD basis vectors for each group of transmission layers to the wireless device (step 902). In one embodiment, the wireless network node can provide an indication indicating the subset of FD basis vectors in the control message (step 902-1). In another embodiment, the wireless network node can provide an indication indicating the subset of FD basis vectors in the DCI (step 902-2). The wireless network node can provide the wireless device with a configuration of a set of CSI-RS ports and an indication indicating one or more non-zero power CSI-RS ports and / or one or more zero power CSI-RS ports in the CSI-RS resource (step 904). Thus, the wireless network node can receive channel measurement values performed based on one or more non-zero power CSI-RS ports from the wireless device (step 906). Next, the wireless network node can receive CSI from the wireless device (block 908). In one embodiment, the wireless network node can receive CSI that does not include an index indicating a subset of the subset of FD basis vectors shown as part of an enhanced type II port selection PMI report (step 908-1). In another embodiment, the wireless network node can receive CSI that includes an index indicating the selected subset among the subset of FD basis vectors shown as part of an enhanced type II port selection PMI report (step 908-2).

[0119] Figure 10 is a flowchart of an exemplary method performed by a wireless device to report CSI. The wireless device receives a subset of FD basis vectors selected from a full set of FD basis vectors (e.g., N3) from a wireless network node (e.g., gNB) (step 1000). In one embodiment, the wireless device can receive a subset of FD basis vectors in a MAC CE (step 1000-1). In another embodiment, the wireless device may receive a subset of FD basis vectors in a DCI (step 1000-2). The wireless device may receive an indication (e.g., via a MAC CE or DCI) from the network node of one or more non-zero power CSI-RS ports or one or more zero power CSI-RS ports out of a set of configured CSI-RS ports (step 1002). Accordingly, the wireless device may perform channel measurements on one or more non-zero power CSI-RS ports (step 1004). The wireless device uses the selected subset of FD basis vectors to calculate CSI corresponding to an enhanced (e.g., Release 16) type II port selection codebook (step 1006). In one embodiment, the wireless device may calculate CSI based on all of the selected subset of FD basis vectors (step 1006-1). In another embodiment, the wireless device may calculate CSI based on a subset of the selected subset of FD basis vectors (step 1006-2). The wireless device reports the CSI to the wireless network node (step 1008). In one embodiment, the wireless device may not report the indices i 1,5 and i 1,6,j as part of an enhanced type II port selection precoding matrix indicator (PMI) report (step 1008-1). In another embodiment, the wireless device may report the indices i 1,5 and i 1,6,j as part of an enhanced type II port selection precoding matrix indicator (PMI) report (step 1008-2).

[0120] FIG. 11 is a flowchart of an exemplary method performed by a wireless network node (e.g., gNB) to enable a wireless device to report CSI. The wireless network node determines a subset of FD basis vectors in a full set of FD basis vectors (e.g., N3) based on one or more uplink measurements performed on SRS received from the wireless device (step 1100). The wireless network node indicates the selected subset of FD basis vectors to the wireless device (step 1102). In one embodiment, the wireless network node can indicate the selected subset of FD basis vectors in a MAC CE (step 1102-1). In another embodiment, the wireless network node may indicate the selected subset of FD basis vectors in DCI (step 1102-2). The wireless network node may provide an indication indicating one or more non-zero power CSI-RS ports or one or more zero power CSI-RS ports to the wireless device (e.g., via MAC CE or DCI) (step 1104). Thus, the wireless network node can receive channel measurement values performed based on one or more non-zero power CSI-RS ports from the wireless device (step 1106). Next, the wireless network node can receive CSI from the wireless device (block 1108). In one embodiment, the wireless network node may not receive indices i 1,5 and i 1,6,j as part of an enhanced type II port selection PMI report (step 1108-1). In another embodiment, the wireless network node can receive indices i 1,5 and i 1,6,j as part of an enhanced type II port selection PMI report (step 1108-2).

[0121] Throughout this disclosure, the terms "basis vectors in the frequency domain" and "basis vectors / matrices in the spatial domain" are used.

[0122] Note that the term "base vector in the frequency domain" may not be part of the 3GPP (registered trademark) standard specification. Instead, the "base vector in the frequency domain" (FD base vector) can be defined as a set of orthogonal complex vectors (e.g., DFT vectors) with a length equal to N3. For example, in 3GPP (registered trademark), the nth base vector in the frequency domain, where n = {0, 1, …, N3 - 1}, can be defined as follows.

[0123] TIFF0007695965000038.tif3470In some cases, the notation f n,l may be used to indicate the nth frequency domain base vector associated with the precoding matrix corresponding to the lth spatial layer.

[0124] Similarly, the term "base vector / matrix in the spatial domain" (SD base vector / matrix) may not be part of the 3GPP (registered trademark) standard specification. Instead, the "base vector / matrix in the spatial domain" can be defined as a set of two-dimensional orthogonal complex vectors (e.g., two-dimensional DFT vectors) with a length equal to N1N2.

[0125] Signaling of Base Vectors in the Frequency Domain via 1-MAC CE In this embodiment (e.g., steps 1000, 1000-1, 1102, 1102-1), a subset of the selected FD base vectors out of the N3 FD bases is indicated to the UE by the gNB via the MAC CE. As shown in the example of FIG. 12, a field consisting of a bitmap of N3 bits (or TIFF0007695965000039.tif1519octets) is used to indicate the selected subset of FD base vectors for CSI feedback using the type II port selection codebook. The bit F set to a value of 1 TIFF0007695965000040.tif1059indicates that the nth FD base vector f n has been selected. The bit F n indicates that the nth FD base vector f nWhen set to a value of 0, this means that the n-th FD basis vector f n is not selected.

[0126] Field F in the MAC CE n has a length of N3 (the number of PMI sub-bands), so the length of field F n depends on the following parameters configured for the UE at the upper layer (e.g., RRC is configured). · Parameter R configured via the upper layer parameter numberOfPMISubbandsPerCQISubband, and · The number of CQI sub-bands in csi-ReportingBand (N SB ) is determined by the sub-band size configured by the upper layer parameter subbandSize and the total number of PRBs in the bandwidth part.

[0127] The above dependency is due to the fact that the number of PMI sub-bands N3 is given by the product of R and the number of CQI (Channel Quality Indicator) sub-bands in csi-ReportingBand (recall N3 = N SB ×R).

[0128] Figure 12 is an exemplary MAC CE configured according to an embodiment of the present disclosure for showing a selected subset of FD basis vectors from a network node to a wireless device. In some embodiments, as shown in Figure 10, the MAC CE for showing a selected subset of FD basis vectors also includes a serving cell ID and / or a bandwidth part (BWP) ID corresponding to a CSI report configuration in which type II port selection codebook-based CSI feedback is configured. Also, as shown in Figure 12, the configuration ID (CSI-ReportConfig ID) of the CSI report configuration is also included as part of the MAC CE.

[0129] Including these in the MAC CE is motivated by the need to flexibly indicate to the UE a selected subset based on FD, configured using different type II port selection codebook-based CSI feedback in different CSI report configurations in the same or different BWPs in different serving cells configured for the UE.

[0130] Each selected FD basis vector is indicated via a single bit in the bitmap of FIG. 12, although the selected FD basis vectors can also be indicated in other forms. For example, in another example, in the MAC CE, each selected FD basis vector can be indicated by TIFF0007695965000041.tif1029 bits in the MAC CE. In this case, to select M FD basis vectors, M × TIFF0007695965000042.tif1029 bits may need to be included in the MAC CE. In another example, one or more combination indicators can be used in the MAC CE to indicate to the UE one or more selected FD basis vectors.

[0131] 1.1 - Embodiment where the number of selected FD bases within the MAC CE is determined by upper layer configuration parameters In one embodiment, the number of FD basis vectors selected and indicated via the MAC CE is TIFF0007695965000043.tif1263, where R is given by the upper layer parameter numberOfPMISubbandsPerCQISubband, and N3 is the number of PMI subbands. The parameter p v,max is determined as the maximum value among, via the upper layer parameter paramCombination - r16, p v , TIFF0007695965000044.tif825 and p v , TIFF0007695965000045.tif725.

[0132] When paramCombination-r16 is set to 4 in the above table, For p corresponding to TIFF0007695965000047.tif825 v The value of For p corresponding to TIFF0007695965000048.tif725 v Is higher than the value of p v,max So p is given by 1 / 4. When the MAC CE indicates to the UE the selection of M max FD basis vectors, the UE can perform the following procedure. · If the UE indicates an RI equal to either 1 or 2, the UE uses all M max FD basis vectors indicated in the MAC CE for type II port selection CSI feedback. Therefore, in this case, the UE does not need to perform FD basis vector selection, and the UE does not need to feedback the selected FD basis vectors to the gNB. This means that the terminal does not need to report the index i 1,5 (Which is reported as part of the PMI in the NR Release 16 enhanced type II port selection codebook - based CSI report). Similarly, the index i 1,6,l (Indicating the selected subset of FD basis vectors to the gNB in the NR Release 16 type II port selection codebook - based CSI report) does not need to be reported by the UE to the gNB as part of the PMI report. This results in a significant saving in CSI report overhead compared to the Release 16 type II enhanced CSI report. · If the UE indicates an RI equal to either 3 or 4, the UE uses a subset of the M max FD basis vectors indicated in the MAC CE for type II port selection CSI feedback. Therefore, at this time, the UE performs FD basis selection only from among the M max FD basis vectors indicated in the MAC CE instead of the total number N3 in the frequency domain that reduces the UE complexity. In this case, the UE has the index i1,5 and i 1,6,l Note that one or more of them can be reported as part of the Release 16 type II port selection PMI report.

[0133] In an alternative embodiment, when the UE indicates a rank indicator (RI) equal to either 1 or 2, the UE uses a subset of the M max FD basis vectors shown in the MAC CE for type II port selection CSI feedback. Thus, in this alternative embodiment, instead of the total number N3 of frequency domain bases that reduce complexity in the UE, the UE performs FD basis vector selection only from among the M max FD basis vectors shown in the MAC CE. In this case, the UE may report one or more of the index i 1,5 and i 1,6,l as part of the Release 16 type II port selection PMI report.

[0134] In some embodiments, when a subset of the FD basis vectors shown in the MAC CE is selected by the UE, the combination coefficient table C(x,y) in Table 5.2.2.2.5-4 of 3GPP (registered trademark) TS 38.214 is used to identify one or more of the i max to be reported by the UE as part of the Release 16 type II port selection PMI report. 1,6,l When identifying one or more of them, the combination coefficient table C(x,y) in Table 5.2.2.2.5-4 of 3GPP (registered trademark) TS 38.214 is used.

[0135] 1.2 Embodiments where the number of selected FD basis vectors shown in the MAC CE changes In this embodiment (e.g., step 1100), the number of selected M flex FD basis vectors shown via the MAC CE is flexibly selected by the gNB based on uplink channel measurements without being restricted by upper layer parameters such as p v , N3, and R.

[0136] In some cases, the maximum number of FD basis vectors that can be selected may be defined via upper layer parameters. For example, the maximum number of FD basis vectors to be selected is given by TIFF0007695965000049.tif1263, where R is given by the upper layer parameter numberOfPMISubbandsPerCQISubband and N3 is the number of PMI subbands. The parameter p v,max is, via the upper layer parameter paramCombination-r16, p v , TIFF0007695965000050.tif825 and p v , determined as the maximum value among TIFF0007695965000051.tif725. Thus, in this exemplary embodiment, the number M of selected FD basis vectors flex = 1, 2, …, M max .

[0137] In a variant of this embodiment, for type II port selection CSI feedback, the UE uses all M flex FD basis vectors indicated in the MAC CE (e.g., step 806-1). Thus, in this case, the UE does not need to perform FD basis vector selection and the UE does not need to feedback the selected FD basis vectors to the gNB. This is beneficial for reducing the complexity of the UE. Further, the UE does not need to report the indexes i 1,5 and i 1,6,l as part of the release 16 type II port selection PMI report, saving overhead (e.g., steps 1008-1, 1108-1).

[0138] In another variant of this embodiment, for type II port selection CSI feedback, the UE uses the M shown in the MAC CE flexUse a subset of the FD basis vectors (e.g., step 1006-2). Thus, in this alternative embodiment, instead of the total number N3 of FD basis vectors that reduce the complexity at the UE in the UE, the UE uses M shown in the MAC CE flex to perform FD basis vector selection only from among the M FD basis vectors. In this case, it should be noted that the UE may report one or more of the indices i 1,5 and i 1,6,l as part of the Release 16 type II port selection PMI report (e.g., steps 1008-2, 1108-2).

[0139] 1.3 Embodiments with different numbers of selected FD basis vectors shown for different numbers of layers In this embodiment, the number of selected FD basis vectors can be indicated in the MAC CE for each layer or for each group of layers. FIG. 13 is an exemplary MAC CE configured according to another embodiment of the present disclosure for showing a selected subset of FD basis vectors from a network node to a wireless device. As shown in FIG. 11, for each layer l (l = 1,..., v), a field consisting of a bitmap of bits (or TIFF0007695965000052.tif1519 octets) is used to indicate a selected subset of FD basis vectors for CSI feedback using a type II port selection codebook having l layers. A bit set to a value of 1 TIFF0007695965000053.tif1264 indicates that the nth FD basis vector f TIFF0007695965000054.tif1011 associated with the precoding matrix corresponding to the lth spatial layer is selected. If the bit n,l is set to 0, this means that the nth FD basis vector f TIFF0007695965000055.tif1011 is not selected. n,l is not selected.

[0140] The example of FIG. 13 shows one field associated with each layer l TIFF0007695965000056.tif1011, but this embodiment can also be generalized when one field within the MAC CE is associated with a group of layers. For example, one such field can be associated with layer l = 1 or 2, and another field can be associated with layer l = 3 or 4.

[0141] In some embodiments, the maximum number of FD basis vectors that can be selected can be defined via higher layer parameters for each layer or group of layers.

[0142] Signaling of frequency domain basis vectors via 2-DCI Another possibility of indicating the FD basis vectors selected via DCI (e.g., steps 1000, 1000-1, 1102, 1102-2).

[0143] In one embodiment, a list of different selected FD basis vectors can be preconfigured by a higher layer (e.g., via RRC), and a field in the DCI can select and indicate to the UE one of the preconfigured lists. For example, one such list can be configured for each CSI-AssociatedReportConfigInfo in the CSI-AperiodicTriggerStateList information element as shown below. In the following example, a range of FDBasisVectorId {0, 1,..., N3 - 1} can be specified. In this exemplary embodiment, different selected lists of FD basis vectors can be triggered via different code points within the CSI request field. That is, code point 1 within the CSI request field can trigger a first CSI-AssociatedReportConfigInfo that includes a first list of selected FD basis vectors, and code point 2 within the CSI request field can trigger a second CSI-AssociatedReportConfigInfo that includes a second list of selected FD basis vectors. CSI-AperiodicTriggerStateList information element TIFF0007695965000057.tif222156

[0144] 3 - Signaling of dynamic spatial domain basis vectors in DCI or MAC CE This embodiment (e.g., steps 1002, 1004, 1106, 1108) addresses the problem that the number of strong clusters changes over time in the channel between the gNB and the UE. This means that the required number of CSI-RS ports will also change. Unless this is addressed, the UE needs to be configured using CSI-RS resources that include the upper limit of the number of CSI-RS ports expected to be required. Alternatively, this embodiment can be used when the N-port CSI-RS resource configuration is shared among multiple UEs. For a given UE, since the other N - L ports are targeted at other UEs, only a subset of L ports is targeted.

[0145] To make the value of N flexible, the UE can be configured using multiple NZP CSI-RS resources with different numbers of CSI-RS ports N, and the appropriate number of ports for a given UE, i.e., the NZP CSI-RS resource, is selected based on UL measurements. For example, if it is determined based on UL measurements that there are L = 6 dominant directions from the UE according to a certain criterion, an NZP CSI-RS resource with N = 8 (N >= L) ports is selected and can be triggered for CSI feedback by the UE, where zero power is transmitted at two of the eight ports. This minimizes overhead as the number of ports used more closely matches the number of ports required at a given time.

[0146] To further reduce the complexity of UE processing, the N - L ports that the gNB determines to transmit with zero power (since L ports are sufficient), or the L ports with non-zero power, can also be signaled to the UE. In this case, the UE simply ignores the N - L ports with zero power and measures and calculates CSI based on the L active (i.e., non-zero power) ports.

[0147] The UE can further select L1 ports (or beams) from L ports (or beams) and report the L1 selected ports and the corresponding CSI coefficients. In this case, the overhead is further reduced for the dynamic signaling of non-zero ports considering that only L ports instead of N ports are actually used in CSI measurements and the port index range is from 0 to L - 1 instead of from 0 to N - 1.

[0148] In one embodiment, ports with non-zero power are always mapped to the first L CSI-RS ports within the N-port NZP CSI-RS resource. Thus, either the value of L or N - L is signaled to the UE. Since the NZP CSI-RS resource can always be selected such that L > N - L, the signaling of N - L can have a smaller overhead. Considering that N = 4, 8, 12, 16, 24, 32 are supported in NR for the type II port selection codebook, it is sufficient to signal N - L non-active ports in the DCI with a maximum of 3 bits.

[0149] The signaling can be done either in the DCI or in the MAC CE. In the case of the MAC CE, alternatively, a P CSI-RS / 2-bit bitmap can be used, and each bit is associated with a CSI-RS port in each of the two polarizations. Pairs of non-zero power CSI-RS ports in different polarizations can be indicated by setting the corresponding bits within the P CSI-RS / 2 bits to '1'. This provides more flexibility when N CSI-RS ports can be shared by multiple UEs and different UEs can use different CSI-RS ports.

[0150] In some embodiments, the signaling of CSI-RS ports with non-zero power is equivalent to the signaling of spatial domain basis vectors.

[0151] In some embodiments, signaling of non-zero power CSI-RS ports (or zero power CSI-RS ports) can be done together with signaling of selected FD basis vectors within the same MAC CE (as covered by embodiments in the section "Signaling of Frequency Domain Basis Vectors via MAC CE" above). That is, different fields or bitmaps in the MAC CE can indicate non-zero power CSI-RS ports (or zero power CSI-RS ports) and selected FD basis vectors. In another embodiment, the presence of one of these fields can be optional in the MAC CE and controlled by bits in the MAC CE. For example, the indication of non-zero power CSI-RS ports (or zero power CSI-RS ports) can be optional in the MAC CE, and bits or flags in the MAC CE can indicate whether a field indicating non-zero power CSI-RS ports (or zero power CSI-RS ports) is present in the MAC CE.

[0152] 4 General Sub-Embodiments 4.1 Activation of Function In some embodiments, the parameter enableFDbasisSelection is configured by the gNB for the UE such that the parameter enables the use of the corresponding MAC CE for selecting FD basis vectors. For example, this parameter can be included in the IE ServingcellConfig as shown below: TIFF0007695965000058.tif25136enableFDbasisSelection When this parameter is present, the Release 17 feature of MAC CE-based FD basis vector selection is enabled. The network configures this parameter only when the UE is configured with a codebookType set as typeII-PortSelection.

[0153] In an alternative embodiment, the activation parameter is for the entire feature of selecting FD basis vectors. This can include the MAC CE example in the first embodiment of this subsection, or the RRC-only option, which means that the UE is given either in an FDI-based manner in RRC signaling or in an option of DCI only as in the section of "Signaling of Frequency Domain Basis Vectors via DCI" above.

[0154] In an alternative embodiment, the parameter is for signaling a selection of a spatial domain basis (or indicating non-zero power or zero power CSI-RS ports) similar to that for FD basis vector selection. In an alternative embodiment, the parameter is for enabling both FD basis vector selection and SD basis vector selection.

[0155] In yet another embodiment, the parameter can enable FD basis, SD basis, or both. TIFF0007695965000059.tif11129enableFDbasisSelection When this parameter is set to fdbasis, the Release 17 (Rel-17) function of FD basis vector selection is enabled. When this parameter is set to sdbasis, the Rel-17 function of SD basis vector selection is enabled. When this parameter is set to both, both the Rel-17 functions of vector selection for FD basis and SD basis are enabled. The network configures this parameter only when the UE is configured with a codebookType set as Type2.

[0156] In another embodiment, any of the above parameters can be effectively set if the UE indicates the corresponding capability.

[0157] 4.2 Timing when MAC CE is assumed to be active at the UE According to this embodiment, after the UE transmits an ACK for receiving the MAC CE, the UE applies the FD / SD basis vectors indicated in the MAC CE within slot X. The value of X may be RRC encoded or may be fixed in the specification.

[0158] FIG. 14 is a schematic block diagram of a radio access node 1400 according to some embodiments of the present disclosure. Optional features are represented by dashed boxes. The radio access node 1400 can be, for example, a base station 702 or 706 or a network node that implements all or part of the functions of the base station 702 or gNB described herein. As shown, the radio access node 1400 includes a control system 1402 that includes one or more processors 1404 (e.g., a Central Processing Unit (CPU), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), etc.), a memory 1406, and a network interface 1408. The one or more processors 1404 are also referred to herein as a processing circuit. Further, the radio access node 1400 may include one or more radio units 1410, each including one or more transmitters 1412 and one or more receivers 1414 coupled to one or more antennas 1416. The radio unit 1410 may be referred to as a radio interface circuit or may be part of a radio interface circuit. In some embodiments, the radio unit 1410 is external to the control system 1402 and is connected to the control system 1402 via, for example, a wired connection (e.g., an optical cable). However, in some other embodiments, the radio unit 1410 and potentially the antenna 1416 are integrated with the control system 1402. The one or more processors 1404 operate to provide one or more functions of the radio access node 1400 as described herein. In some embodiments, the functions are implemented by software stored, for example, in the memory 1406 and executed by the one or more processors 1404.

[0159] FIG. 15 is a schematic block diagram showing a virtualized embodiment of a wireless access node 1400 according to some embodiments of the present disclosure. This description is equally applicable to other types of network nodes. Further, other types of network nodes can have a similar virtualization architecture. Also, optional features are represented by dashed boxes.

[0160] As used herein, a “virtualized” wireless access node is an implementation of a wireless access node 1400, and at least a portion of the functionality of the wireless access node 1400 is implemented as virtual component(s) (e.g., via virtual machine(s) running on physical processing node(s) in the network). As shown, in this example, the wireless access node 1400 may include a control system 1402 and / or one or more radio units 1410 as described above. The control system 1402 may be connected to the radio unit 1410, for example, via an optical cable or the like. The wireless access node 1400 includes one or more processing nodes 1500 coupled to or included as part of the network 1502. If present, the control system 1402 or the radio unit is connected to the processing node 1500 via the network 1502. Each processing node 1500 includes one or more processors 1504 (e.g., CPU, ASIC, FPGA, etc.), a memory 1506, and a network interface 1508.

[0161] In this example, the functionality 1510 of the wireless access node 1400 described herein is implemented in one or more processing nodes 1500, or is distributed across one or more processing nodes 1500, the control system 1402, and / or the radio unit 1410 in any desired manner. In some particular embodiments, some or all of the functionality 1510 of the wireless access node 1400 described herein is implemented as virtual components executed by one or more virtual machines implemented in a virtual environment hosted by the processing node 1500. As will be understood by those skilled in the art, additional signaling or communication between the processing node 1500 and the control system 1402 is used to execute at least some of the desired functionality 1510. In particular, in some embodiments the control system 1402 may not be included, in which case the radio unit 1410 communicates directly with the processing node 1500 via an appropriate network interface.

[0162] In some embodiments, there is provided a computer program including instructions that, when executed by at least one processor, cause the at least one processor to perform one or more of the functionality 1510 of the wireless access node 1400 in a virtual environment according to any of the embodiments described herein. In some embodiments, there is provided a carrier (medium) including the aforementioned computer program product. The carrier is one of an electrical signal, an optical signal, a wireless signal, or a computer-readable storage medium (e.g., a non-transitory computer-readable medium such as a memory).

[0163] FIG. 16 is a schematic block diagram of a wireless access node 1400 according to some other embodiments of the present disclosure. The wireless access node 1400 includes one or more modules 1600, each implemented in software. The modules 1600 provide the functionality of the wireless access node 1400 described herein. This description is equally applicable to the processing nodes 1500 of FIG. 15, where the modules 1600 can be implemented at one of the processing nodes 1500, or distributed across multiple processing nodes 1500, and / or distributed across the processing nodes 1500 and the control system 1402.

[0164] FIG. 17 is a schematic block diagram of a wireless communication device 1700 according to some embodiments of the present disclosure. As shown, the wireless communication device 1700 includes one or more processors 1702 (e.g., CPU, ASIC, FPGA, etc.), a memory 1704, and one or more transceivers 1706 each including one or more transmitters 1708 and one or more receivers 1710 coupled to one or more antennas 1712. The transceiver 1706 includes a radio front-end circuit connected to the antenna 1712 configured to condition signals communicated between the antenna 1712 and the processor 1702, as understood by those skilled in the art. The processor 1702 may also be referred to herein as a processing circuit. The transceiver 1706 may also be referred to herein as a radio circuit. In some embodiments, the functionality of the wireless communication device 1700 described above may be implemented fully or partially by software stored in the memory 1704 and executed by the (one or more) processors 1702. Note that the wireless communication device 1700 may include additional components not shown in FIG. 17, such as, for example, one or more user interface components (e.g., an input / output interface including a display, buttons, touch screen, microphone, speaker, etc., and / or any other component enabling input of information to the wireless communication device 1700 and / or output of information from the wireless communication device 1700), a power supply (e.g., a battery and associated power circuitry).

[0165] In some embodiments, there is provided a computer program comprising instructions that, when executed by at least one processor, cause the at least one processor to perform the functions of the wireless communication device 1700 according to any of the embodiments described herein. In some embodiments, there is provided a carrier containing the aforementioned computer program product. The carrier is one of an electrical signal, an optical signal, a wireless signal, or a computer-readable storage medium (e.g., a non-transitory computer-readable medium such as a memory).

[0166] FIG. 18 is a schematic block diagram of a wireless communication device 1700 according to some other embodiments of the present disclosure. The wireless communication device 1700 includes one or more modules 1800 each implemented in software. The modules 1800 provide the functions of the wireless communication device 1700 described herein.

[0167] Referring to FIG. 19, according to one embodiment, a communication system includes a telecommunication network 1900 such as a 3GPP (registered trademark) type cellular network including an access network 1902 such as a RAN and a core network 1904. The access network 1902 includes a plurality of base stations 1906A, 1906B, 1906C such as Node B, eNB, gNB, or other types of wireless access points (APs) each defining a corresponding coverage area 1908A, 1908B, 1908C. Each base station 1906A, 1906B, 1906C is connectable to the core network 1904 via a wired or wireless connection 1910. A first UE 1912 located in the coverage area 1908C is configured to wirelessly connect to or be paged by the corresponding base station 1906C. A second UE 1914 within the coverage area 1908A is wirelessly connectable to the corresponding base station 1906A. Although multiple UEs 1912, 1914 are shown in this example, the disclosed embodiments are equally applicable to situations where only one UE is within a coverage area or only one UE is connected to the corresponding base station 1906.

[0168] The telecommunications network 1900 is itself connected to a host computer 1916, which may be embodied in the hardware and / or software of a stand-alone server, a cloud-implemented server, a distributed server, or as processing resources in a server farm. The host computer 1916 may be under the ownership or control of a service provider, or may be operated by or on behalf of a service provider. The connections 1918 and 1920 between the telecommunications network 1900 and the host computer 1916 may extend directly from the core network 1904 to the host computer 1916, or may pass through an optional intermediate network 1922. The intermediate network 1922 may be one of a public network, a private network, or a hosted network, or a combination of two or more of them. The intermediate network 1922, if any, may be a backbone network or the Internet. In particular, the intermediate network 1922 may include two or more sub-networks (not shown).

[0169] The communication system of FIG. 19 enables connectivity overall between the connected UEs 1912, 1914 and the host computer 1916. The connectivity can be described as an Over-the-Top (OTT) connection 1924. The host computer 1916 and the connected UEs 1912, 1914 are configured to communicate data and / or signals via the OTT connection 1924 using the access network 1902, the core network 1904, any intermediate network 1922, and any additional infrastructure (not shown) acting as an intermediary. The OTT connection 1924 can be transparent in the sense that participating communication devices through which the OTT connection 1924 passes do not know the routing of the uplink and downlink communications. For example, the base station 1906 need not be informed about the past routing of the incoming downlink communication for data transmitted from the host computer 1916 to be forwarded (e.g., handed over) to the connected UE 1912, or vice versa. Similarly, the base station 1906 need not recognize the future routing of the outgoing uplink communication from the UE 1912 towards the host computer 1916.

[0170] Here, an exemplary implementation according to the embodiments of the UE, base station, and host computer discussed in the previous paragraph will be described with reference to FIG. 20. In communication system 2000, host computer 2002 comprises hardware 2004 including a communication interface 2006 configured to establish and maintain a wired or wireless connection with interfaces of different communication devices of communication system 2000. Host computer 2002 further comprises a processing circuit 2008 that may have storage and / or processing capabilities. In particular, processing circuit 2008 may comprise one or more programmable processors, ASICs, FPGAs, or combinations thereof (not shown) adapted to execute instructions. Host computer 2002 further comprises software 2010 that is stored on or accessible by host computer 2002 and executable by processing circuit 2008. Software 2010 includes a host application 2012. Host application 2012 may be operable to provide services, such as UE 2014, that connect via an OTT connection 2016 that terminates at UE 2014 and host computer 2002, to remote users. When providing services to remote users, host application 2012 may provide user data transmitted using OTT connection 2016.

[0171] The communication system 2000 further includes a base station 2018 provided within a telecommunications system and comprising hardware 2020 that enables communication with a host computer 2002 and a UE 2014. The hardware 2020 may include a communication interface 2022 for setting up and maintaining a wired or wireless connection with an interface of different communication devices of the communication system 2000, and a wireless interface 2024 for setting up and maintaining at least a wireless connection 2026 with a UE 2014 located in a coverage area (not shown in FIG. 20) served by the base station 2018. The communication interface 2022 may be configured to facilitate a connection 2028 to the host computer 2002. The connection 2028 may be direct, or may pass through a core network (not shown in FIG. 20) of the telecommunications system, and / or may pass through one or more intermediate networks external to the telecommunications system. In the illustrated embodiment, the hardware 2020 of the base station 2018 further includes a processing circuit 2030 that may comprise one or more programmable processors, ASICs, FPGAs, or combinations thereof (not shown) adapted to execute instructions. The base station 2018 further has software 2032 stored internally or accessible via an external connection.

[0172] The communication system 2000 further includes the UE 2014 that has been previously referenced. The hardware 2034 of the UE 2014 may include a radio interface 2036 configured to set up and maintain a radio connection 2026 with a base station serving the coverage area where the UE 2014 is currently located. The hardware 2034 of the UE 2014 further includes a processing circuit 2038 that may comprise one or more programmable processors, ASICs, FPGAs, or combinations thereof (not shown) adapted to execute instructions. The UE 2014 further comprises software 2040 that is stored in or accessible by the UE 2014 and executable by the processing circuit 2038. The software 2040 includes a client application 2042. The client application 2042 may be operable to provide services to a human or non-human user via the UE 2014 using the support of the host computer 2002. In the host computer 2002, the running host application 2012 can communicate with the running client application 2042 via the OTT connection 2016 that terminates at the UE 2014 and the host computer 2002. When providing services to the user, the client application 2042 can receive request data from the host application 2012 and provide user data in response to the request data. The OTT connection 2016 can transfer both request data and user data. The client application 2042 can interact with the user to generate the user data it provides.

[0173] Note that the host computer 2002, base station 2018, and UE 2014 shown in FIG. 20 may be similar or identical to one of the host computer 1916, one of the base stations 1906A, 1906B, 1906C, and one of the UEs 1912, 1914 of FIG. 19, respectively. That is, the internal operations of these entities are as shown in FIG. 20, and independently, the surrounding network topology may be that of FIG. 19.

[0174] In FIG. 20, an OTT connection 2016 abstractly depicts communication between a host computer 2002 and a UE 2014 via a base station 2018 without explicitly referring to any intermediate devices and without showing the exact routing of messages through these devices. The network infrastructure can determine the routing, which can be configured to hide the routing from the UE 2014, or from the service provider operating the host computer 2002, or from both. While the OTT connection 2016 is active, the network infrastructure can further make a decision to dynamically change the routing (e.g., based on load balancing considerations or network reconfiguration).

[0175] A wireless connection 2026 between the UE 2014 and the base station 2018 complies with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE 2014 using the OTT connection 2016 that forms the last segment.

[0176] The measurement procedure can be provided for the purpose of monitoring data rate, latency, and other factors that one or more embodiments improve. In response to variations in the measurement results, there may further be optional network functions for reconfiguring the OTT connection 2016 between the host computer 2002 and the UE 2014. The measurement procedure and / or network functions for reconfiguring the OTT connection 2016 can be implemented in the software 2010 and hardware 2004 of the host computer 2002, or in the software 2040 and hardware 2034 of the UE 2014, or in both. In some embodiments, a sensor (not shown) can be deployed within or associated with a communication device through which the OTT connection 2016 passes, and the sensor can participate in the measurement procedure by providing values of the monitored quantities exemplified above, or by providing values of other physical quantities whose values can be calculated or estimated by the software 2010, 2040 for the monitored quantities. The reconfiguration of the OTT connection 2016 can include message format, retransmission settings, preferred routing, etc., and the reconfiguration need not affect the base station 2018 and can be unknown or imperceptible to the base station 2018. Such procedures and functions are known in the art and can be practiced. In certain embodiments, the measurement can involve unique UE signaling that facilitates measurement of the throughput, propagation time, latency, etc. of the host computer 2002. The measurement can be implemented in that the software 2010 and 2040 cause messages, particularly empty or "dummy" messages, to be transmitted using the OTT connection 2016 while monitoring propagation time, errors, etc.

[0177] FIG. 21 is a flowchart showing a method implemented in a communication system according to an embodiment. The communication system includes a host computer, a base station, and a UE, which may be those described with reference to FIGS. 19 and 20. For simplicity of the present disclosure, only the drawing reference to FIG. 21 is included in this section. In step 2100, the host computer provides user data. In sub-step 2102 (which may be optional) of step 2100, the host computer provides user data by executing a host application. In step 2104, the host computer starts a transmission to carry the user data to the UE. In step 2106 (which may be optional), the base station transmits the user data carried in the transmission started by the host computer to the UE according to the teachings of the embodiments described throughout the present disclosure. In step 2108 (which may be optional), the UE executes a client application related to the host application executed by the host computer.

[0178] FIG. 22 is a flowchart showing a method implemented in a communication system according to an embodiment. The communication system includes a host computer, a base station, and a UE, which may be those described with reference to FIGS. 19 and 20. For simplicity of the present disclosure, only the drawing reference to FIG. 22 is included in this section. In step 2200 of the method, the host computer provides user data. In any sub-step (not shown), the host computer provides user data by executing a host application. In step 2202, the host computer starts a transmission to carry the user data to the UE. The transmission may pass through the base station according to the teachings of the embodiments described throughout the present disclosure. In step 2204 (which may be optional), the UE receives the user data carried in the transmission.

[0179] FIG. 23 is a flowchart showing a method implemented in a communication system according to one embodiment. The communication system includes a host computer, a base station, and a UE, which may be those described with reference to FIGS. 19 and 20. For simplicity of the present disclosure, only the drawing reference to FIG. 23 is included in this section. In step 2300 (which may be optional), the UE receives input data provided by the host computer. Additionally or alternatively, in step 2302, the UE provides user data. In sub-step 2304 (which may be optional) of step 2300, the UE provides user data by executing a client application. In sub-step 2306 (which may be optional) of step 2302, the UE executes a client application that provides user data in response to the received input data provided by the host computer. When providing user data, the executed client application can further consider user input received from the user. Regardless of the particular method by which user data is provided, the UE starts transmitting the user data to the host computer in sub-step 2308 (which may be optional). In step 2310 of the method, the host computer receives the user data transmitted from the UE in accordance with the teachings of the embodiments described throughout the present disclosure.

[0180] FIG. 24 is a flowchart showing a method implemented in a communication system according to an embodiment. The communication system includes a host computer, a base station, and a UE, which may be those described with reference to FIGS. 19 and 20. For the sake of simplicity of the present disclosure, only the drawing reference to FIG. 24 is included in this section. In step 2400 (which may be optional), according to the teachings of the embodiments described throughout the present disclosure, the base station receives user data from the UE. In step 2402 (which may be optional), the base station starts transmitting the received user data to the host computer. In step 2404 (which may be optional), the host computer receives the user data carried in the transmission started by the base station.

[0181] Any suitable steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual devices. Each virtual device may comprise several of these functional units. These functional units may be implemented via one or more microprocessors or microcontrollers as logic processing circuitry, as well as other digital hardware such as digital signal processors (DSPs), dedicated digital logic, etc. The processing circuitry may be configured to execute program code stored in a memory, which may include one or several types of memory such as read-only memory (ROM), random access memory (RAM), cache memory, flash memory devices, optical storage devices, etc. The program code stored in the memory includes program instructions for executing one or more telecommunication and / or data communication protocols, and instructions for executing one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause each functional unit to perform the corresponding functions according to one or more embodiments of the present disclosure.

[0182] The processes in the figures may show a specific order of operations executed by some embodiments of the present disclosure, but it should be understood that such an order is exemplary (for example, alternative embodiments may execute the operations in a different order, combine some operations, overlap some operations, etc.).

[0183] Some exemplary embodiments of the present disclosure are as follows.

[0184] Embodiment 1: A method is provided that is executed by a wireless device to report channel state information (CSI). The method includes receiving (1000) a selected subset of FD basis vectors from a network node (e.g., gNB) within a complete set of frequency domain (FD) basis vectors (e.g., N3), calculating (1006) CSI corresponding to an enhanced (e.g., Release 16) type II port selection codebook using the selected FD basis vectors, and reporting (1008) the CSI to the network node, and includes one or more of these.

[0185] Embodiment 2: The complete set of FD basis vectors includes a set of orthogonal complex vectors having a length equal to N3.

[0186] Embodiment 3: Receiving (800) a subset of FD basis vectors includes receiving (1000-1) a selected subset of FD basis vectors in a media access control (MAC) control element (CE).

[0187] Embodiment 4: The MAC CE includes a region (e.g., an N3-bit bitmap or TIFF0007695965000060.tif1129-bit bitmap) configured to indicate a selected subset of FD basis vectors within the complete set of FD basis vectors.

[0188] Embodiment 5: Each MAC CE is configured to indicate a selected subset of FD basis vectors from a full set of FD basis vectors for each of a plurality of layers, and includes a plurality of fields (e.g., an N3-bit bitmap or TIFF0007695965000061.tif an 1129-bit bitmap).

[0189] Embodiment 6: Receiving (1000) a subset of FD basis vectors includes receiving (1000-2) a selected subset of FD basis vectors in downlink control information (DCI).

[0190] Embodiment 7: The DCI corresponds to a code point and includes a field (e.g., CSI-AssociatedReportConfigInfo) configured to indicate a selected subset of FD basis vectors from a full set of FD basis vectors.

[0191] Embodiment 8: The method also includes receiving (1002), from a network node (e.g., via a MAC CE or DCI), an indication of one or more non-zero power CSI reference signal (CSI-RS) ports, or one or more zero power CSI-RS ports. The method also includes performing channel measurements (1004) on one or more non-zero power CSI-RS ports.

[0192] Embodiment 9: Calculating (1006) the CSI using the selected FD basis vectors includes calculating (1006-1) the CSI based on all of the selected subset of FD basis vectors. Reporting the CSI (1008) includes not reporting (1008-1) indices i 1,5 and i 1,6,l as part of an enhanced type II port selection PMI report.

[0193] Embodiment 10: Calculating the CSI using the selected FD basis vectors (1006) includes calculating the CSI (1006-2) based on a subset of a selected subset of the FD basis vectors. Reporting the CSI (1008) includes reporting indexes i 1,5 and i 1,6,l as part of an enhanced type II port selection PMI report (1008-2).

[0194] Embodiment 11: The method also includes providing user data and transferring the user data to a host computer via transmission to a base station.

[0195] Embodiment 12: A method performed by a base station (e.g., gNB) is provided to enable a wireless device to report channel state information (CSI). The method comprises one or more of indicating to the wireless device a subset of the FD basis vectors selected from a complete set of FD basis vectors (e.g., N3) (1102) and receiving the CSI from the wireless device (1108).

[0196] Embodiment 13: The method also includes determining (1100) a subset of the FD basis vectors of the full set of FD basis vectors based on one or more uplink measurements performed on the SRS received from the wireless device.

[0197] Embodiment 14: Indicating the subset of the FD basis vectors (1102) includes indicating (1102-1) the selected subset of the FD basis vectors in a media access control (MAC) control element (CE).

[0198] Embodiment 15: The MAC CE is a field configured to indicate a subset of the FD basis vectors selected from the complete set of FD basis vectors (e.g., an N3-bit bitmap or TIFF0007695965000062.tif (1129-bit bitmap).

[0199] Embodiment 16: Each MAC CE is configured with a plurality of fields (e.g., an N3-bit bitmap or TIFF0007695965000063.tif (1129-bit bitmap)) each showing a subset of FD basis vectors selected from a complete set of FD basis vectors for each of a plurality of layers. TIFF0007695965000063.tif (1129-bit bitmap).

[0200] Embodiment 17: Indicating a subset of FD basis vectors (1102) includes receiving (1102-2) the selected subset of FD basis vectors in downlink control information (DCI).

[0201] Embodiment 18: The DCI corresponds to a code point and includes a field (e.g., CSI-AssociatedReportConfigInfo) configured to indicate the selected subset of FD basis vectors among the full set of FD basis vectors.

[0202] Embodiment 19: The method also includes providing (1104) an indication of one or more non-zero power CSI reference signal (CSI-RS) ports, or one or more zero power CSI-RS ports, to a wireless device (e.g., via a MAC CE or DCI). The method also includes receiving (1106) channel measurement values performed based on one or more non-zero power CSI-RS ports from the wireless device.

[0203] Embodiment 20: Receiving CSI (1108) includes not receiving (1108-1) or receiving (1108-2) indices i 1,5 and i 1,6,l as part of an enhanced type II port selection PMI report.

[0204] Embodiment 21: The method also includes acquiring user data and transferring the user data to a host computer or a wireless device.

[0205] Embodiment 22: A wireless device for reporting channel state information (CSI) is provided. The wireless device including a processing circuit is configured to execute any of the steps of any of the embodiments executed by the wireless device. The wireless device also includes a power supply circuit configured to supply power to the wireless device.

[0206] Embodiment 23: A base station for enabling a wireless device to report channel state information (CSI) is provided. The base station includes a processing circuit configured to execute any of the steps of any of the embodiments executed by the base station. The base station also includes a power supply circuit configured to supply power to the base station.

[0207] Embodiment 24: A user equipment (UE) for reporting channel state information (CSI) is provided. The UE includes an antenna configured to transmit and receive wireless signals. The UE also includes a radio front-end circuit connected to the antenna and the processing circuit and configured to adjust signals communicated between the antenna and the processing circuit. The processing circuit is configured to execute any of the steps of any of the embodiments executed by the wireless device. The UE also includes an input interface connected to the processing circuit and configured to enable input of information to the UE to be processed by the processing circuit. The UE also includes an output interface connected to the processing circuit and configured to output information processed by the processing circuit from the UE. The UE also includes a battery connected to the processing circuit and configured to supply power to the UE.

[0208] Embodiment 25: A communication system including a host computer. The host computer includes a processing circuit configured to provide user data, and a communication interface configured to transfer the user data to a cellular network for transmission to a user equipment (UE). The cellular network includes a base station having a wireless interface and a processing circuit, and the processing circuit of the base station is configured to execute any of the steps of any of the embodiments executed by the base station.

[0209] Embodiment 26: The communication system further includes a base station.

[0210] Embodiment 27: The communication system further includes a UE, and the UE is configured to communicate with the base station.

[0211] Embodiment 28: The processing circuit of the host computer is configured to execute a host application, thereby providing user data. The UE includes a processing circuit configured to execute a client application associated with the host application.

[0212] Embodiment 29: A method implemented in a communication system including a host computer, a base station, and a user equipment (UE). The method includes, at the host computer, providing user data. The method also includes, at the host computer, initiating a transmission to convey the user data to the UE via a cellular network including the base station, and the base station executes any of the steps of any of the embodiments executed by the base station.

[0213] Embodiment 30: The method further includes, at the base station, transmitting the user data.

[0214] Embodiment 31: The user data is provided at the host computer by executing a host application, and the method further includes, at the UE, executing a client application associated with the host application.

[0215] Embodiment 32: A user equipment (UE) configured to communicate with a base station. The UE includes a radio interface and a processing circuit configured to execute the methods of the three foregoing embodiments.

[0216] Embodiment 33: A communication system including a host computer. The host computer includes a processing circuit configured to provide user data and a communication interface configured to transfer the user data to a cellular network for transmission to a user equipment (UE). The UE comprises a radio interface and a processing circuit, and components of the UE are configured to execute any of the steps of any of the embodiments executed by a radio device.

[0217] Embodiment 34: The cellular network further includes a base station configured to communicate with the UE.

[0218] Embodiment 35: The processing circuit of the host computer is configured to execute a host application, thereby providing user data. The processing circuit of the UE is configured to execute a client application associated with the host application.

[0219] Embodiment 36: A method implemented in a communication system including a host computer, a base station, and a user equipment (UE). The method includes providing user data at the host computer. The method also includes initiating, at the host computer, a transmission to convey the user data to the UE via a cellular network including the base station. The UE executes any of the steps of any of the embodiments executed by a radio device.

[0220] Embodiment 37: The method also includes receiving, at the UE, the user data from the base station.

[0221] Embodiment 38: A communication system including a host computer. The host computer includes a communication interface configured to receive user data transmitted from a user equipment (UE) to a base station. The UE includes a wireless interface and a processing circuit. The processing circuit of the UE is configured to execute any of the steps of any of the embodiments executed by a wireless device.

[0222] Embodiment 39: The communication system further includes a UE.

[0223] Embodiment 40: The communication system further includes a base station. The base station includes a wireless interface configured to communicate with the UE, and a communication interface configured to transfer user data carried by a transmission from the UE to the base station to the host computer.

[0224] Embodiment 41: The processing circuit of the host computer is configured to execute a host application. The processing circuit of the UE is configured to execute a client application related to the host application, thereby providing user data.

[0225] Embodiment 42: The processing circuit of the host computer is configured to execute a host application, thereby providing request data. The processing circuit of the UE is configured to execute a client application associated with the host application, thereby providing user data in response to the request data.

[0226] Embodiment 43: A method implemented in a communication system including a host computer, a base station, and a user equipment (UE). The method includes receiving, at the host computer, user data transmitted from the UE to the base station. The UE executes any of the steps of any of the embodiments executed by a wireless device.

[0227] Embodiment 44: The method also includes providing user data to a base station at a UE.

[0228] Embodiment 45: The method also includes executing a client application at a UE, thereby providing user data to be transmitted. The method also includes executing a host application associated with the client application at a host computer.

[0229] Embodiment 46: The method also includes executing a client application at a UE. The method also includes receiving input data at the UE for the client application, the input data being provided at a host computer by executing a host application associated with the client application. The user data to be transmitted is provided by the client application in response to the input data.

[0230] Embodiment 47: A communication system including a host computer having a communication interface configured to receive user data transmitted from a transmission from a user equipment (UE) to a base station. The base station includes a radio interface and a processing circuit. The processing circuit of the base station is configured to execute any of the steps of any of the embodiments executed by the base station.

[0231] Embodiment 48: The communication system further includes a base station.

[0232] Embodiment 49: The communication system further includes a UE. The UE is configured to communicate with the base station.

[0233] Embodiment 50: The processing circuit of the host computer is configured to execute a host application. The UE executes a client application associated with the host application, thereby being configured to provide user data to be received by the host computer.

[0234] Embodiment 51: A method implemented in a communication system including a host computer, a base station, and a user equipment (UE). The method includes, at the host computer, receiving from the base station user data derived from a transmission received by the base station from the UE. The UE executes any of the steps of any of the embodiments executed by a wireless device.

[0235] Embodiment 52: The method also includes, at the base station, receiving user data from the UE.

[0236] Embodiment 53: The method also includes, at the base station, starting to transmit the received user data to the host computer.

[0237] Embodiment 54: A method for signaling, from a network (e.g., eNB), a selected subset of frequency domain (FD) basis vectors from a complete set N3 of FD basis vectors to a user equipment (UE). The FD basis vectors include a set of orthogonal complex vectors of length equal to N3. The method comprises the UE using the selected subset of FD basis vectors to calculate channel state information (CSI) corresponding to an enhanced (e.g., 3GPP (registered trademark) Release 16) type II port selection codebook.

[0238] Embodiment 55: The selected subset of FD basis vectors is signaled via a media access control (MAC) control element (CE).

[0239] Embodiment 56: The MAC CE has a field of length N3, and each bit in the field indicates whether an FD basis vector in the complete set of FD basis vectors is selected.

[0240] Embodiment 57: The MAC CE is configured to indicate the maximum number of FD basis vectors.

[0241] Embodiment 58: The maximum number of FD basis vectors is determined via one or more upper layer configuration parameters.

[0242] Embodiment 59: A selected subset of FD basis vectors is signaled via downlink control information (DCI).

[0243] Embodiment 60: The UE calculates CSI using all of the selected FD basis vectors.

[0244] Embodiment 61: The UE does not feedback index i 1,5 and i 1,6,l as part of an enhanced type II port selection PMI report.

[0245] Embodiment 62: The UE calculates CSI using a subset of the selected FD basis vectors.

[0246] Embodiment 63: The UE reports one or more of index i 1,5 and i 1,6,l as part of an enhanced type II port selection PMI report.

[0247] Embodiment 64: The network further indicates to the UE a subset of non-zero power CSI-RS ports among a set of configured CSI-RS ports for channel measurement.

[0248] Embodiment 65: The network further indicates to the UE zero power CSI-RS ports among a set of configured CSI-RS ports.

[0249] Embodiment 66: The UE performs channel measurements on one or more CSI-RS ports that are not indicated as zero power CSI-RS ports in the set of CSI-RS ports.

[0250] In the present disclosure, at least some of the following abbreviations can be used. If there are inconsistencies between the abbreviations, it is preferable how they are used above. If described multiple times below, the first list should be given precedence over subsequent lists. · 3GPP Third Generation Partnership Project · 5G Fifth Generation · 5GC Fifth Generation Core · 5GS Fifth Generation System · AF Application Function · AMF Access and Mobility Function · AN Access Network · AP Access Point · ASIC Application Specific Integrated Circuit · Ausf Authentication Server Function · BWP Bandwidth Part · CPU Central Processing Unit · CQI Channel Quality Indicator · CSI Channel State Information · DCI Downlink Control Information · DL Downlink · DN Data Network · DSP Digital Signal Processor · eNB Enhanced or Evolved Node B · EPS Evolved Packet System · E-UTRA Evolved Universal Terrestrial Radio Access · FD Frequency Domain · FDD Frequency Division Duplexing · FPGA Field Programmable Gate Array · gNB New Radio Base Station · gNB-DU New Radio Base Station Distributed Unit · HSS Home Subscriber Server · IMR Interference Measurement Resource · IoT Internet of Things · IP Internet Protocol · LTE Long Term Evolution ·MAC Media Access Control ·MCS Modulation and Coding Scheme ·MIMO Multiple-Input Multiple-Output ·MME Mobility Management Entity ·MTC Machine-Type Communication ·NEF Network Exposure Function ·NF Network Function ·NR New Radio ·NRF Network Function Repository Function ·NSSF Network Slice Selection Function ·NZP Non-Zero Power ·OFDM Orthogonal Frequency Division Multiplexing ·OTT Over-the-Top ·PC Personal Computer ·PCF Policy Control Function ·PDSCH Physical Downlink Shared Channel ·P-GW Packet Data Network Gateway ·PMI Precoder Matrix Indicator ·PS Port Selection ·PUSCH Physical Uplink Shared Channel ·QoS Quality of Service ·RAM Random Access Memory ·RAN Radio Access Network ·RE Resource Element ·RI Rank Indicator ·ROM Read-Only Memory ·RRH Remote Radio Head ·RS Reference Signal ·RTT Round Trip Time ·SCEF Service Capability Exposure Function ·SD Spatial Domain ·SMF Session Management Function ·SRS Sounding Reference Signal ·TDD Time Division Duplexing ·TFRE Time / Frequency Resource Element ·UDM Unified Data Management · UE User Equipment · UL Uplink · UPF User Plane Function Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered to be within the scope of the concepts disclosed herein.

Claims

1. A method performed by a wireless device for reporting channel state information (CSI), comprising: receiving (800) in downlink control information (DCI) from a wireless network node an indication indicating a subset of FD basis vectors from a complete set of FD basis vectors for each group of transmission layers in a frequency domain (FD); calculating (806) CSI corresponding to an enhanced type II port selection codebook using the indicated subset of FD basis vectors; reporting (808) the CSI to the wireless network node; and a method comprising the steps of:

2. The method according to claim 1, wherein the complete set of FD basis vectors comprises a set of orthogonal complex vectors having a length equal to N 3 and a method comprising the steps of:

3. The method according to claim 2, wherein N 3 is determined by the upper layer parameters numberOfPMISubbandsPerCQISubband and csi-ReportingBand.

4. The method according to any one of claims 1 to 3, wherein receiving (800) the indication indicating the subset of FD basis vectors comprises receiving (800-1) in a control message the indication indicating the subset of FD basis vectors.

5. The method according to claim 4, wherein the control message is a media access control (MAC) control element (CE).

6. The method according to claim 5, wherein the MAC CE comprises a field configured to indicate the subset of FD basis vectors among the complete set of FD basis vectors.

7. The method according to claim 6, wherein the field in the MAC CE is a bitmap of N3 bits, and a bitmap of bits including one of them.

8. The method according to claim 5, wherein the MAC CE comprises a plurality of fields each configured to indicate a subset of the FD basis vectors from a complete set of the FD basis vectors for each layer of a plurality of layers.

9. The method according to claim 8, wherein the field in the MAC CE is N 3 a bitmap of bits, and a bitmap of bits including one of them.

10. The method according to claim 1, wherein the DCI is a field corresponding to a code point, the field being configured to indicate a subset of the FD basis vectors from a complete set of the FD basis vectors.

11. The method according to claim 10, wherein the field of the DCI comprises CSI-AssociatedReportConfigInfo corresponding to the code point.

12. The method according to any one of claims 1 to 11, further comprising receiving (802), from the radio network node, a configuration of a CSI-RS resource having a set of CSI-RS ports and an indication indicating one or more non-zero power CSI-RS ports within the CSI-RS resource and indicating one or more zero power CSI-RS ports within the CSI-RS resource. and an indication indicating one or more of them. Performing channel measurements based on the one or more non-zero power CSI-RS ports (804); A method comprising.

13. The method according to any one of claims 1 to 12, Calculating the CSI using the subset of the indicated FD basis vectors (806) includes calculating the CSI based on all of the subset of the indicated FD basis vectors (806-1), Reporting the CSI (808) includes not transmitting an index indicating a subset of the subset of the indicated FD basis vectors as part of an enhanced type II port selection precoding matrix indicator (PMI) report (808-1). A method.

14. The method according to any one of claims 1 to 12, Calculating the CSI using the subset of the indicated FD basis vectors (806) includes calculating the CSI based on a selected subset of the subset of the indicated FD basis vectors (806-2), Reporting the CSI (808) includes reporting an index indicating the selected subset of the subset of the indicated FD basis vectors as part of an enhanced type II port selection precoding matrix indicator (PMI) report (808-2). A method.

15. A wireless device (1700) comprising a processing circuit (1702, 1706), wherein the processing circuit (1702, 1706) causes the wireless device (1700) to Receive an indication indicating a subset of FD basis vectors from a complete set of FD basis vectors in the frequency domain (FD) for each group of transmission layers in downlink control information (DCI) (800); Using the subset of the FD basis vectors shown, cause CSI corresponding to an enhanced type II port selection codebook to be calculated (806), cause the CSI to be reported (808) to the radio network node, A radio device (1700) configured as such.

16. The radio device according to claim 15, wherein the processing circuit (1702, 1706) is further configured to cause the radio device (1700) to execute any of the steps according to any one of claims 2 to 14. A radio device.

17. A method performed by a radio network node to enable a radio device to report channel state information (CSI), Determining (900) a subset of FD basis vectors from a complete set of FD basis vectors in the frequency domain (FD) based on one or more uplink measurements performed on the sounding reference signal (SRS) received from the radio device; Providing (902) an indication to the radio device of the subset of FD basis vectors from among the complete set of FD basis vectors for each group of transmission layers; Receiving (908) CSI from the radio device; A method comprising:

18. The method according to claim 17, wherein providing (902) the indication indicating the subset of FD basis vectors includes providing (902-1) the indication indicating the subset of FD basis vectors in a control message. A method.

19. The method according to claim 18, wherein the control message is a media access control (MAC) control element (CE).

20. The method according to claim 19, wherein the MAC CE comprises a field configured to indicate a subset of the indicated FD basis vectors of the complete set of the FD basis vectors. **Claim 21** The method according to claim 20, wherein the field in the MAC CE is N 3 a bitmap of bits, and a bitmap of bits and includes one of. **Claim 22** The method according to claim 19, wherein the MAC CE comprises a plurality of fields each configured to indicate a subset of the indicated FD basis vectors of the complete set of the FD basis vectors for each of the plurality of layers. **Claim 23** The method according to claim 22, wherein the field in the MAC CE is N 3 a bitmap of bits, and a bitmap of bits and includes one of. **Claim 24** The method according to claim 17, wherein providing the indication (902) indicating the subset of the FD basis vectors includes providing the indication (902-2) indicating the subset of the FD basis vectors in downlink control information (DCI). **Claim 25** The method according to claim 24, wherein the DCI is a field corresponding to a code point and comprises a field configured to indicate the subset of the FD basis vectors of the complete set of the FD basis vectors. **Claim 26** The method according to claim 25, wherein the field of the DCI comprises CSI-AssociatedReportConfigInfo corresponding to the code point.

27. The method according to any one of claims 17 to 26, further comprising: configuring, for the wireless device, a CSI-RS resource having a set of ports of a CSI reference signal (CSI-RS), and an indication that one or more non-zero power CSI-RS ports within the CSI-RS resource and / or one or more zero power CSI-RS ports within the CSI-RS resource, providing an indication thereof (904); receiving, from the wireless device, channel measurements performed based on the one or more non-zero power CSI-RS ports (906); A method comprising.

28. The method according to any one of claims 17 to 27, wherein receiving the CSI (908) comprises: receiving the CSI that does not include an index indicating a subset of the subset of the FD basis vectors shown as part of an enhanced type II port selection precoding matrix indicator (PMI) report (908-1); receiving the CSI that includes an index indicating a selected subset of the subset of the FD basis vectors shown as part of an enhanced type II port selection precoding matrix indicator (PMI) report (908-2); A method including any of.

29. A wireless network node (1400) comprising a processing circuit (1402), wherein the processing circuit (1402) causes the wireless network node (1400) to Based on one or more uplink measurements performed on sounding reference signals (SRS) received from a wireless device, determining (900) a subset of FD basis vectors from a complete set of FD basis vectors in the frequency domain (FD), causing the wireless device to provide (902) an indication indicating the subset of FD basis vectors from among the complete set of FD basis vectors for each group of transmission layers, causing CSI to be received (908) from the wireless device, A wireless network node (1400) configured as such. **Claim 30** A wireless network node according to claim 29, wherein the processing circuit (1402) is further configured to cause the wireless network node (1400) to perform any of the steps according to any one of claims 17 to 28.

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