CSI reporting based on ternary codebooks

Abstract

The present invention relates to a method performed by a user equipment (UE) that provides CSI feedback in the form of one or more channel state information (CSI) reports in a wireless communication system (A), the method comprising: receiving, from a network node (gNB) via a MIMO channel, one or more higher layer configurations of downlink reference signals, one or more CSI report configurations associated with the downlink reference signal configurations, and a wireless signal, the wireless signal including a downlink reference signal associated with the one or more downlink reference signal configurations; estimating a downlink MIMO channel based on measurements on the received one or more downlink reference signals, the downlink reference signals being provided via a configured number of frequency domain resources, time domain resources, and one or more ports; estimating, for each CSI report configuration, an estimated channel matrix and two codebooks, one or more spatial domain (SD) precoders. determining a precoding matrix based on two codebooks, including a spatial codebook including basis components and a delay codebook including one or more delay-domain (DD) basis components of a precoder, and one or more non-zero combining coefficients that complex-combines the one or more SD and DD basis vectors; reporting one or more CSI reports of one or more CSI report configurations to a network node, each CSI report including a selected precoding matrix in the form of a precoding matrix identifier PMI and a rank identifier RI, where the rank identifier (RI) indicates the transmission rank of the RI layer of the precoding matrix; each CSI report including two parts: CSI Part 1 and CSI Part 2, where CSI Part 1 has a fixed payload size and includes information indicating the size of the payload of CSI Part 2, and CSI Part 2 includes at least amplitude and phase information of the selected non-zero combining coefficients of the CSI report, and part or all of CSI Part 2 is available for omission from the CSI report.

Description

[Technical field]

[0001] The present invention relates to the field of wireless communications, and in particular to a method, a user equipment, a network node and a computer program product for providing channel state information (CSI) feedback in the form of one or more CSI reports from a user equipment in a wireless communications system. [Background technology]

[0002] In wireless communication systems such as the 3GPP fifth generation wireless communication system or New Radio, also called 5G for short, downlink (DL) and uplink (UL) signals carry data signals, control signals including DL control information (DCI) and / or uplink control information (UCI), and several reference signals (RS) used for different purposes. A radio network node, or radio base station, or gNode B (or gNB or gNB / TRP (Transmit Reception Point)) transmits data and DCI through the so-called physical downlink shared channel (PDSCH) and physical downlink control channel (PDCCH), respectively.

[0003] The UE transmits data and UCI through so-called physical uplink shared channel (PUSCH) and physical uplink control channel (PUCCH), respectively. Furthermore, each DL or UL signal of a gNB, i.e., user equipment (UE) or wireless device, may include one or more types of RS, including channel state information RS (CSI-RS), demodulation RS (DM-RS), and sounding RS (SRS). CSI-RS (SRS) is transmitted in the DL (UL) system bandwidth portion and is used in the UE (gNB) for CSI acquisition. DM-RS is transmitted only in the bandwidth portion of each PDSCH / PUSCH and is used by the UE / gNB for data demodulation.

[0004] One of the many key features of 5G is the use of multiple-input multiple-output (MIMO) transmission schemes to achieve higher system throughput compared to previous generation mobile systems. MIMO transmissions generally require the availability of accurate CSI, which is used by the gNB to precode the signals using precoding matrices for data and control information. Thus, the current Third Generation Partnership Project Release 15 specifications (3GPP Release 15) provide a comprehensive framework for CSI reporting. The CSI is obtained in a first step at the UE based on the received CSI-RS signal transmitted by the gNB. In a second step, the UE determines a precoding matrix from a predefined set of matrices called a "codebook" based on the estimated channel matrix. In a third step, the selected precoding matrix is ​​reported to the gNB in ​​the form of a precoding matrix identifier (PMI) and a rank identifier (RI).

[0005] Dual Stage Precoding and CSI Report in 3GPP Release 15 In the current Release 15NR specification, there are two types of CSI reporting (Type I and Type II), both of which rely on a dual-stage, i.e., two-component W1W2 codebook. The first component, i.e., first-stage precoder W1, is used to select the number of beam vectors and, if set, rotation oversampling factors from a Discrete Fourier Transform-based (DFT-based) matrix, also called spatial codebook. The spatial codebook contains DFT or oversampling DFT matrices of dimensions N1N2×N1O1N2O2, where O1 and O2 denote the oversampling factors for the first and second dimensions of the codebook, respectively. The DFT vectors in the codebook are grouped into (q1,q2), 0≦q1≦O1-1, 0≦q2≦O2-1 subgroups, where each subgroup contains N1N2 DFT vectors, and the parameters q1 and q2 are denoted as rotation oversampling factors. The second component, the so-called second stage precoder W2, is used to combine the selected beam vectors.

[0006] Assuming rank R transmission and a dual polarized antenna array in a gNB with configuration (N1,N2,2), the Release 15 double stage precoder disclosed in [1] for the sth subband and the rth transmission layer is

[0007]

number

[0008]

number

[0009]

number

[0010] In the 3GPP Release 15 Dual Stage Type II CSI report, the second stage precoder W2 is

[0011]

number

[0012]

number

[0013] Assuming rank R transmission, the ternary precoder matrix or CSI matrix for the 2N1N2 antenna / DL-RS ports and N3 subbands is given by

[0014]

number

[0015]

number

[0016]

number

[0017] The main advantage of the three-component CSI reporting scheme in equation (2) is that the feedback overhead of reporting the combining coefficients of the precoder matrix or CSI matrix is ​​no longer dependent on the number of frequency-domain subbands configured, i.e., it is independent of the system bandwidth. Furthermore, the feedback overhead and performance of the precoder matrix or CSI matrix can be reduced by the third component W2 on a layer-by-layer or all-layer basis. (r)can be included in p, and can be controlled by the gNB by setting the maximum number of non-zero coupling coefficients K reported by the UE to the UE. Since only the amplitude and phase information of the non-zero coupling coefficients is reported, an indicator such as a bitmap is needed to indicate which of the 2UD coefficients per layer are selected and reported by the UE. According to [5], the selected non-zero coefficients of the rth layer are indicated by a bitmap, where each bit in the bitmap is associated with a polarization index (p∈{1,2}), an SD basis index (0≦u≦U-1), and a DD basis index (0≦d≦D-1). A "1" in the bitmap indicates that the coupling coefficients associated with the polarization index p, the SD basis index u, and the DD basis index are non-zero and are selected and reported by the UE. A "0" in the bitmap indicates that the coupling coefficients associated with the polarization index p, the SD basis vector u, and the DD basis index d are zero, and thus are not reported by the UE.

[0018] According to [6], the strongest coupling coefficient for each layer is normalized to 1 and is not reported. A strongest coefficient indicator (SCI) is reported by the UE for each layer to indicate which of the 2UD coefficients of a layer is the strongest coupling coefficient.

[0019] According to [6] (Non-Patent Document 6), the non-zero coupling coefficient γ (p,u,d) (r) (W2 (r) Included in the following:

[0020]

number

[0021] Construction and reporting of three-component CSI method For the configuration of the precoder matrix or the CSI matrix, the CSI reporting configuration may be signaled from the gNB to the UE via higher layers (e.g., RRC), and the higher layer CSI reporting configuration may include the following information [7]: - a parameter U indicating the number of SD basis vectors to be selected by the UE from the spatial codebook for the computation of W1; - W3 (r) A parameter D or variants thereof indicating the number of DD basis vectors to be selected by the UE per layer from the delay codebook for the computation of - matrix W2 for each layer or for all layers (r) a parameter K, or a variant thereof, which indicates a maximum number of non-zero coefficients used by the UE to combine the selected SD basis vector and the DD basis vector; A parameter N3 indicating the number of frequency domain subbands of the CSI matrix and the dimension of the DD basis vectors in the delay codebook; and - Additional parameters for reporting configuration of DD basis vectors.

[0022] The CSI report includes at least a rank indicator (RI) that indicates the selected number of layers in the CSI matrix, and the ranks of all layers K NZ and a PMI that defines three components of the CSI matrix, the PMI including at least the following information [7]: - a spatial domain subset indicator indicating the U SD basis vectors selected from the spatial codebook of the RI layer of the CSI matrix and, if set, the selected oversampling rotation factors; - delay domain subset indicators indicating the selected DD basis vectors for each layer, - a layer-wise strongest coefficient indicator (SCI), which is not reported and indicates the SD basis index or the SD and DD basis index associated with the strongest combination coefficient; - K for each layer NZ,r amplitude and phase information associated with the selected non-zero quantized delay domain combining coefficients; - K per layer NZ,r a per-layer bitmap indicating the SD and DD basis indices associated with the non-zero coefficients; - Polarization-specific reference amplitudes per layer, as well as - Additional possible parameters associated with the DD Basis Subset directive.

[0023] Omission of UCI in CSI reporting in 3GPP Release 15 PUSCH-based resource allocation and UCI omission in CSI reporting [1] was introduced in 3GPP Release 15. It allows the UE to drop some parts of one or more CSI reports if the PUSCH resource allocation is not sufficient to carry the entire content of the CSI report. UCI omission may occur if the base station does not correctly allocate PUSCH resources when scheduling the CSI report. For example, the base station may allocate resources for a rank-1 (RI=1) CSI report, but the UE decides on rank-2 transmission and reports a rank-2 (RI=2) CSI report with a size larger than the size of the allocated PUSCH resources. In such a case, the UE needs to drop some of the UCI content. In 3GPP Release 15, the dropping is achieved by breaking down the UCI payload associated with the CSI report into smaller parts, so-called priority levels. See Table 5.2.3-1 in [1]. In this table, priority level 0 has the highest priority and priority level N REP Here, UCI represents the total number of CSI reports configured to be carried on the PUSCH. Each priority level is associated with a portion of the CSI report. The UE drops the lower priority CSI portion so that the payload size of the CSI report matches the PUSCH resource allocation. Furthermore, the CSI payload is split into two parts: CSI part 1 and CSI part 2. CSI part 1 includes an RI and an indicator indicating the size of CSI part 2. The size of CSI part 1 is fixed, while the size of CSI part 2 varies depending on the RI and several other factors determined by the UE. Because the gNB needs to know CSI part 1 to decode CSI part 2, UCI omission is performed only for CSI part 2.

[0024] CSI part 2 is 2N REP +1 CSI parts, where 2N REP The CSI parts, so-called subband PMI, are REPThe CSI report PMI includes CSI content associated with even and odd subbands. In addition, each subband PMI includes 2N subbands, starting with index 1. REP In addition, the first CSI portion associated with priority level index 0 is associated with all 2N REP The Rel-15 subband-based CSI decomposition and omission method includes information on subband PMIs, i.e., the entire CSI reporting band. The motivation behind the Rel-15 subband-based CSI decomposition and omission method is that if the first subband PMI of CSI report n is omitted, the gNB may use the CSI content of the reported second subband PMI of CSI report n and estimate the CSI of the omitted first subband PMI by using an interpolation scheme. In this way, a severe degradation in performance can be avoided since neighboring subbands are typically highly correlated. [Prior art documents] [Non-patent literature]

[0025] [Non-Patent Document 1] 3GPP TS 38.214 V15.3.0: "3GPP;TSG RAN;NR;Physical layer procedures for data (Rel.15)," September 2018. [Non-Patent Document 2] Samsung, "Revised WID: Enhancements on MIMO for NR", RP-182067, 3GPP RAN#81, Gold Coast, Australia, September 10-13, 2018 [Non-Patent Document 3] R1-1806124, Fraunhofer IIS, Fraunhofer HHI, Enhancements on Type-II CSI reporting scheme, RAN1#93, Busan, Korea, May 21-25, 2018 [Non-Patent Document 4] R1-1811088, Fraunhofer IIS, Fraunhofer HHI, Enhancements on Type-II CSI reporting scheme, RAN1#94-Bis, Chengdu, China, October 8-12, 2018 [Non-Patent Document 5] Chairman's Notes, RAN1#96, Athens, Greece, February 25-March 1, 2019 [Non-Patent Document 6] R1-1902304, Samsung, Summary of CSI enhancement for MU-MIMO, RAN1#96, February 25th - March 1st, 2019 [Non-Patent Document 7] R1-1905629, Samsung, Feature lead summary for MU-CSI-revision on selected issues, Xi'an, China, April 12-16, 2019 Summary of the Invention [Means for solving the problem]

[0026] For the known 3-component CSI reporting schemes, there is no subband-based PMI and it is not possible to decompose CSI part 2 into several subband PMIs, so the UCI omission procedure of 3GPP Release 15 cannot be reused. Therefore, a new UCI omission rule is needed.

[0027] It should be noted that in a three-component CSI reporting scheme, the CSI payload of a CSI report can be controlled by the UE by the number of non-zero coefficients to be reported. In the case of UCI omission, the UE may simply reduce the number of non-zero coefficients to be reported in one or more of the CSI reports based on the available PUSCH resources. However, reducing the number of non-zero combining coefficients requires recalculation of combining coefficients, SD and DD basis vectors of the CSI matrix of one or more CSI reports, occupying additional UE resources. Such additional UE resources are not available to the UE. Therefore, the UCI omission scheme should not require recalculation of the CSI matrix of one or more CSI reports.

[0028] In the 3-component CSI reporting scheme, the size of the payload of the CSI report is mainly determined by the bitmap of the reported non-zero coupling coefficients and the amplitude and phase information of the CSI report.

[0029] In this invention, a different segmentation scheme of the bitmap and amplitude and phase information of the reported non-zero coupling coefficients of the CSI report in the 3-component CSI reporting scheme is proposed. In one solution of the present invention, the UCI omission scheme is based on dropping part of the amplitude and phase information of the non-zero coupling coefficients of the CSI report.

[0030] In another solution of the invention, the UCI omission scheme is based on dropping part of the amplitude and / or phase information of the non-zero combination coefficients and part of the bitmap associated with the dropped combination coefficients.

[0031] The present invention provides a method performed by a user equipment (UE) for providing channel state information (CSI) feedback in the form of one or more CSI reports in a wireless communication system, the method comprising: receiving, from a network node (gNB) via a MIMO channel, higher layer configurations of one or more downlink reference signals, one or more CSI report configurations associated with the downlink reference signal configurations, and a wireless signal, the wireless signal including a downlink reference signal in accordance with the one or more downlink reference signal configurations; - estimating a downlink MIMO channel based on measurements on one or more received downlink reference signals, the downlink reference signals being provided via a configured number of frequency domain resources, time domain resources, and one or more ports; for each CSI report configuration, an estimated channel matrix and two codebooks, - a spatial codebook including one or more spatial domain (SD) basis components of the precoder; and - determining a precoding matrix based on two codebooks, including a delay codebook including one or more delay-domain (DD) basis components of a precoder, and one or more non-zero combining coefficients that complex combine the one or more SD and DD basis vectors; reporting one or more CSI reports of one or more CSI report configurations to a network node.

[0032] Each CSI report includes a selected precoding matrix in the form of a precoding matrix identifier (PMI) and a rank identifier (RI), where the rank identifier (RI) indicates the transmission rank of the RI layer of the precoding matrix, and each CSI report includes two parts, CSI part 1 and CSI part 2, where CSI part 1 has a fixed payload size and includes information indicating the size of the payload of CSI part 2. CSI part 2 includes at least amplitude and phase information of the selected non-zero combining coefficients and a bitmap of all RI layers indicating the non-zero combining coefficients of the CSI report, and the bitmap of each layer is segmented into D bit sequences with respect to the DD basis index of the selected DD basis vector. Each bit sequence includes 2U×1 bits associated with 2U spatial beams, where U denotes the number of SD basis vectors selected from the spatial codebook, each DD basis index is associated with a delay vector from the delay codebook, and the D bit sequences are ordered with respect to one of two ordering schemes of the N3 DD basis indexes, where N3 denotes the number of DD basis indexes of the delay codebook, and the N3 DD basis indexes are ordered as 0, 1, N3-1, 2, N3-2, 3, N3-3, 4, N3-4, 5, according to a first ordering scheme, or the N3 DD basis indexes are ordered as 0, N3-1, 1, N3-2, 2, N3-3, 3, N3-4, 4, N3-5, 5, according to a second ordering scheme. The ordering of the amplitude and phase information of the combining coefficients follows the ordering of the bit sequences of the bitmaps of all the RI layers. Part or all of CSI portion 2 is available for omission from the CSI report.

[0033] According to one proposed aspect of the present invention, CSI part 1 includes at least information about the selected number of non-zero combining coefficients across all RI layers and an indication of the transmission rank of the RI layer of the selected precoding matrix.

[0034] CSI part 2 includes at least the following information about the RI layer of the selected precoding matrix: - a spatial domain (SD) basis subset indicator including a rotational oversampling factor if a rotational oversampling factor is set, indicating a selected SD basis vector from the spatial codebook; - one or more delay-domain (DD) basis subset indicators indicating selected DD basis vectors from a delay codebook; - the phase and amplitude of the selected non-zero delay region coupling coefficients, - the strongest coefficient indicator SCI, which shows the DD and SD vectors associated with the strongest coefficient per layer, - Polarization reference amplitudes per layer, - a bitmap indicating the non-zero coupling coefficients per layer, as well as - additional possible parameters associated with the DD Basis Subset directive It is also proposed to include

[0035] Another aspect of the present invention is REP CSI part 2 of this CSI report is TN REP +1 CSI subgroups, where T CSI subgroups are always associated with a single CSI report, and one CSI subgroup is associated with all N REP The present invention teaches that each CSI subgroup includes information associated with a CSI report, and that each CSI subgroup is associated with a priority, i.e., a priority level.

[0036] All N REP The CSI subgroup containing information associated with the CSI report may have the highest priority, i.e., priority level 0, and the remaining TN REP CSI subgroups have lower priority levels 1 to TN REP and the last CSI subgroup TN REP is the lowest priority level TN REP It is proposed to be associated with

[0037] The CSI subgroups are: Priority 0: CSI Reports 1~N REPJoint CSI Subgroup of Part 2 of Priority 1: CSI Subgroup 1 of Part 2 of CSI Report 1 ... Priority T: CSI Subgroup T of Part 2 of CSI Report 1 Priority T+1: CSI Subgroup 1 of Part 2 of CSI Report 2 Priority 2T: CSI Subgroup T of Part 2 of CSI Report 2 ... Priority T(N REP -1)+1:CSI Report N REP CSI Subgroup 1 of Part 2 ... Priority TN REP :CSI Report N REP CSI subgroup T of part 2 It is also proposed that the priority order may be according to:

[0038] In case of omission, it is proposed that the UE may drop CSI subgroups with lower priority until the payload size of the CSI report matches the resource allocation from the gNB. When omitting a CSI subgroup of a particular priority level, the UE may omit all CSI content of that priority level.

[0039] The parameter T may indicate the number of CSI subgroups per CSI report and may be related to the granularity of the CSI content omitted from the CSI report, with a high value of T indicating high granularity and a low value of T indicating low granularity, such that if the parameter T is given a value of “2”, each CSI report is associated with only two CSI subgroups.

[0040] In one proposed aspect of the present invention, the first CSI subgroup, called the joint CSI subgroup, is associated with priority level 0 and all N REP The Joint CSI subgroup includes the CSI information of the CSI reports, and the Joint CSI subgroup includes the following parameters: - if a rotational oversampling factor is set, the selected SD basis subset indicator including the rotational oversampling factor; and - SCI in the RI layer The present invention teaches that the present invention includes at least one piece of information.

[0041] The CSI sub-group with the highest priority for CSI reporting must have at least the following parameters: - selected DD basis subset indicators for the RI layer, - the polarization reference amplitude value of the RI layer, - K in RI layer NZ a bitmap indicating the non-zero coupling coefficients; and - additional possible parameters associated with the DD Basis Subset directive It is also proposed to include information on:

[0042] A proposed aspect of the present invention is that the CSI subgroup with the highest priority for a CSI report comprises at least the following parameters: - selected DD basis subset indicators for the RI layer, - the polarization reference amplitude value of the RI layer, - K in RI layer NZ a bitmap indicating the non-zero coupling coefficients; and - Window parameter M init The information contained herein is intended to be accurate and up to date.

[0043] It is also proposed that the corresponding ordered bitmaps of the RI layers may be grouped together into a bitmap of size 2UD×RI and segmented into D segments, each segment having size 2U×RI, and the dth segment being associated with 2U SDs of all the RI layers.

[0044] It is proposed that bits in a bit segment associated with the same SD base index for all layers may be grouped together and sorted with respect to increasing layer index, with the RI bits associated with the first SD base index being grouped together, followed by the RI bits associated with the second SD base index, and so on.

[0045] Another aspect of the invention is that ordering the DD basis indexes for each layer according to the second ordering scheme comprises ordering the DD basis indexes for each layer according to the formula:

[0046]

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[0047]

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[0048] Yet another aspect of the invention is that the ordering of bits in a bitmap is determined according to the formula:

[0049]

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[0050]

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[0051] Another aspect of the present invention is that the first segment of the CSI subgroup having the highest priority may be associated with DD basis vector index 0. Another aspect of the present invention is that, for a CSI report, the UE may be configured to perform a circular shift operation on the DD basis vectors selected for the selected combining coefficients and layer with respect to the DD basis vectors associated with the SCI such that the DD basis vector with index 0 is associated with the SCI.

[0052] This means that the CSI subgroup with the highest priority for each CSI report may contain information of a first portion of the amplitude and phase values ​​of the selected non-zero delay domain combining coefficients, and the remaining T−1 CSI subgroups of lower priority may contain the remaining portions of the amplitude and phase values ​​of the CSI report.

[0053] Each CSI subgroup with the highest priority and associated with a single CSI report is assigned at least a portion of the RI layer bitmap and NZ It is also proposed that the phase and amplitude information of the portion of the non-zero combined coefficients may be included.

[0054] This means that the CSI subgroup with the highest priority is RI=ν layer bitmap

[0055]

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[0056]

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[0057]

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[0058] It is proposed that each CSI subgroup with the highest priority associated with a single CSI report may include at least a portion of the bitmap and information of the coupling coefficient associated with the DD basis vector index of the SCI of the RI layer.

[0059] It is also proposed that each CSI subgroup having the highest priority and associated with a single CSI report may include at least a bitmap associated with one or more DD basis vector indices for the RI layer of the precoding matrix indicated in the CSI report, and that the CSI subgroup may include corresponding amplitude and / or phase information of the combining coefficients associated with the bitmap.

[0060] Each CSI subgroup containing information on a portion of the coupling coefficients is

[0061]

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[0062] Then, the CSI subgroup with the highest priority per CSI report is

[0063]

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[0064]

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[0065]

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[0066]

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[0067]

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[0068]

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[0069] Then, for each CSI report, the CSI subgroup with the highest priority is associated with an amplitude value.

[0070]

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[0071]

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[0072]

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[0073]

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[0074]

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[0075] The present invention also relates to a User Equipment (UE) comprising a processor and a memory, the memory comprising computer program code executable by the processor, whereby the UE is operable to execute any one of the subject methods of the present invention executed by the user equipment.

[0076] The present invention also relates to a network node comprising a processor and a memory, the memory comprising computer program code executable by the processor, whereby the network node is operable to execute any one of the subject methods of the present invention executed by the network node.

[0077] The invention also relates to a computer program product comprising computer program code which, when executed by a processor, enables the processor to carry out any one of the subject matter of the methods of the invention in relation to a user equipment.

[0078] The invention also relates to a computer program product comprising computer program code which, when executed by a processor, enables the processor to carry out any one of the subject matter of the methods of the invention in relation to a network node.

[0079] The present invention provides a method in which a new UCI omission rule is implemented that enables UEs using known 3-component CSI reporting schemes to utilize the omission procedure without the need to recalculate the combining coefficients, SD and DD basis vectors of the CSI matrix for one or more CSI reports.

[0080] Example embodiments and advantages of the embodiments herein are described in more detail with reference to the accompanying drawings. [Brief description of the drawings]

[0081] [Figure 1] FIG. 1 is a simplified schematic diagram of user equipment communicating with a radio base station; [Diagram 2] FIG. 1 is a diagram of a scheme 1 showing an example of decomposition of CSI portion 2 into several CSI subgroups, in which NREP CSI subgroups having priority levels (t-1)NREP to tNREP-1 (1≦t≦T) are always associated with NREP CSI reports. [Diagram 3]FIG. 1 is a diagram of a scheme 1 showing the decomposition of the CSI portion 2 into several CSI subgroups, where T CSI subgroups having priority levels (n-1)T to nT-t (1≦n≦NREP) are always associated with a single CSI report. [Figure 4] FIG. 2 is a diagram of a scheme 2 illustrating an example of decomposition of CSI portion 2 into several CSI subgroups, where the first CSI subgroup with the highest priority contains information from CSI report 1 to NREP, and T CSI subgroups with priority levels (n-1)T+1 to nT (1≦n≦NREP) are always associated with a single CSI report. [Diagram 5] FIG. 2 is a diagram of a scheme 2 showing an example of decomposition of CSI portion 2 into several CSI subgroups, in which the first CSI subgroup with the highest priority contains information from CSI report 1 to NREP, and NREP CSI subgroups with priority levels (t−1)NREP+1 to tNREP (1≦t≦T) are always associated with NREP CSI reports. [Figure 6] FIG. 1 is a diagram of an example of CSI content included in a first joint CSI subgroup having priority level 0 and CSI content of a CSI subgroup having the highest priority and associated with a single CSI report n. [Figure 7] FIG. 13 is a diagram of an example of CSI content included in a first joint CSI subgroup having priority level 0 and CSI content of T CSI subgroups associated with CSI report n. [Figure 8] FIG. 11 is a diagram of CSI content for T=2 CSI subgroups for the third method of decomposition scheme 1. [Figure 9] FIG. 1 is a diagram of CSI content of a first and second CSI subgroup associated with CSI report t with segmentation into D segments, where D denotes the number of configured delay vectors per layer of the CSI matrix of CSI report t. [Figure 10] FIG. 13 is an illustration of a further segmentation of segment k into subsegments, where each subsegment is associated with all SD components and DD basis indices of a single layer. [Figure 11] 1 is an illustration of the segmentation of segment k into kr,2U subsegments, where each subsegment is associated with all the SD components and DD basis indices of a single layer. [Figure 12] FIG. 13 is a diagram of segmentation of the bitmap contained in a CSI subgroup into RI segments, each of which is 2 UD bits. [Figure 13] FIG. 13 is a diagram of segmentation of a bitmap of size 2UD×1 into sub-segments, each of size 2U×1. [Figure 14] FIG. 13 is a diagram of segmentation of a bitmap of size 2UD×1 into sub-segments each of size 2D×1. [Figure 15] A diagram of segmentation of a bitmap of size 2UD×1 into sub-segments each of size D×1. [Figure 16] FIG. 13 is a diagram of segmentation of a bitmap into D segments, each of size 2U×RI bits. [Figure 17] A diagram of segmentation of a 2U×RI bit segment into sub-segments, each of which is 2 RI bits. [Figure 18] A diagram of segmentation of a 2U x RI bit segment into sub-segments, each of which is an RI bit. [Figure 19] A diagram of segmentation of 2U×RI bits into sub-segments of 2U bits each. [Figure 20] FIG. 13 is a diagram of phase information followed by amplitude information for each coupling coefficient. [Figure 21] FIG. 13 is a diagram of amplitude information of all X combining coefficients followed by phase information of all X combining coefficients. [Figure 22] 13 is a diagram of amplitude information of all X combining coefficients followed by phase information of all X combining coefficients. [Diagram 23] FIG. 2 is a schematic diagram of a first scheme for ordering DD basis indexes. [Figure 24] FIG. 13 is a schematic diagram of a second scheme for ordering DD basis indexes. [Diagram 25] A diagram of the mapping of spatial beam indices to indices gl,u and gl,U+u. [Figure 26] 13 is a diagram of a mapping of spatial beam index u,∀u=0,···,2U−1 and bits associated with segment Ad to index gl,u,∀u=0,···,2U−1. [Figure 27] 13 is a diagram of a mapping of bits associated with spatial beam index u,∀u=0,···,2U−1 to index gl,u,∀u=0,···,2U−1 when the strongest coefficient is associated with the first polarization with U=4. [Figure 28] 13 is a diagram of a mapping of bits associated with spatial beam index u,∀u=0,···,2U−1 to index gl,u,∀u=0,···,2U−1 when the strongest coefficient is associated with the first polarization with U=4. [Figure 29] 13 is a diagram of a mapping of bits associated with spatial beam index u,∀u=0,···,2U−1 to index gl,u,∀u=0,···,2U−1 when the strongest coefficient is associated with the second polarization with U=4. [Diagram 30] 13 is a diagram of a mapping of bits associated with spatial beam index u,∀u=0,···,2U−1 to index gl,u,∀u=0,···,2U−1 when the strongest coefficient is associated with the first polarization with U=4. [Diagram 31] 13 is an illustration of the mapping of the bitmap associated with spatial beam index u,∀u=0,···,2U−1 to index gl,u,∀u=0,···,2U−1. [Diagram 32] 13 is an illustration of the mapping of the bitmap associated with spatial beam index u,∀u=0,···,2U−1 to index gl,u,∀u=0,···,2U−1. [Diagram 33] 1 is a simplified schematic diagram of a user equipment and a computer program product. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0082] Below, detailed descriptions of example embodiments in several scenarios in conjunction with figures are presented to make the solutions described herein easier to understand. As mentioned above, in the new wireless system of 3GPP, the UCI omission procedure is standardized in Release 15, and the omission procedure cannot be reused because there is no subband-based PMI and it is not possible to decompose the CSI part 2 into several subband PMIs. Therefore, a new UCI omission rule is needed.

[0083] FIG. 1 is a simplified diagram of a method performed by a user equipment (UE) and a radio base station (gNB) to provide channel state information (CSI) feedback in the form of a CSI report in a wireless communication system A, the method comprising: receiving, from a network node (gNB) via a MIMO channel, higher layer configurations of one or more downlink reference signals, one or more CSI report configurations associated with the downlink reference signal configurations, and a wireless signal, the wireless signal including a downlink reference signal according to the one or more downlink reference signal configurations; - estimating a downlink MIMO channel based on measurements on one or more received downlink reference signals, the downlink reference signals being provided via a configured number of frequency domain resources, time domain resources, and one or more ports; for each CSI report configuration, an estimated channel matrix and two codebooks, - a spatial codebook including one or more spatial domain (SD) basis components of the precoder; and - determining a precoding matrix based on two codebooks, including a delay codebook including one or more delay domain (DD) basis components of the precoder, and one or more non-zero combining coefficients that complex combine the one or more SD and DD basis vectors; reporting one or more CSI reports of one or more CSI report configurations to a network node.

[0084] Each CSI report includes a selected precoding matrix in the form of a precoding matrix identifier (PMI) and a rank identifier (RI) indicating the transmission rank of the RI layer of the precoding matrix, and each CSI report includes two parts: CSI part 1 and CSI part 2, where CSI part 1 has a fixed payload size and includes information indicative of the size of the payload of CSI part 2. CSI part 2 includes at least amplitude and phase information of selected non-zero combining coefficients of the CSI report, and part or all of CSI part 2 is available for omission from the CSI report.

[0085] According to one embodiment, the UE is provided with N REP CSI reports may be configured, with each CSI report including two parts: CSI part 1 and CSI part 2, where CSI part 1 has a fixed payload size and is used to indicate the size of the payload of CSI part 2. CSI part 1 may include at least information about the number of combining coefficients across all layers and the transmission rank (RI) of the RI layer of the selected precoding matrix. CSI part 2 of the CSI report may include at least the following information for the RI layer of the selected CSI matrix for the configured antenna port and subband: - the selected SD basis subset indicator, including the rotational oversampling factor, if set, - selected DD basis subset indicators per layer, - phases and amplitudes of selected non-zero delay region coupling coefficients per layer, - strongest coefficient indicator (SCI) for each layer, - Polarization reference amplitudes per layer, - a bitmap indicating the non-zero coupling coefficients per layer, as well as - Additional possible parameters associated with the DD basis subset indication.

[0086] Decomposition for CSI part 2 - Method 1 According to the embodiment, in the first decomposition method (method 1), N REP CSI part 2 of the CSI report is N REP The T CSI subgroups may be segmented into T CSI subgroups, where T CSI subgroups are always associated with a single CSI report. Furthermore, each CSI subgroup is associated with a priority level, with the first subgroup having the highest priority level 0. The remaining T REP - One CSI subgroup has lower priority levels 1 to TN REP Associated with -1. Last CSI subgroup TN REP -1 is the lowest priority level TN REP It can be associated with -1.

[0087] FIG. 2 shows a first example of the method 1. In FIG. 2, the priority level (t-1)N REP From tN REP -1 (1≦t≦T), and N REP N CSI reports associated with REP The CSI subgroups are always grouped together.

[0088] FIG. 3 shows a second example of the method 1. In FIG. 3, priority levels (n-1)T to nT-t (1≦n≦N REP ), where the T CSI subgroups associated with a single CSI report are always grouped together.

[0089] The parameter T indicates the number of CSI subgroups per CSI report and is related to the granularity of the CSI content omitted from the CSI report. A high value of T indicates high granularity and a low value of T indicates low granularity. If the parameter T is given a value of "2", each CSI report is associated with only two CSI subgroups.

[0090] The parameter T, which indicates the number of CSI subgroups per CSI report, may also depend on the CSI report. In one example, the parameter T may depend on the rank indicated in the CSI report. For example, if the rank indicated in the CSI report is greater than 1, i.e., RI>1, then T=2, and if the rank indicated in the CSI report is 1, i.e., RI=1, then T=1. In another example, the parameter T may depend on the rank of the CSI report. Number number K NZ For example, the number of non-zero coefficients reported in the CSI report may depend on a certain threshold, i.e.

[0091]

number

[0092] In case of UCI omission, the UE drops CSI subgroups of lower priority until the payload size of the CSI report matches the PUSCH resource allocation. When a CSI subgroup of a particular priority level is omitted, the UE omits all CSI content of that priority level.

[0093] Decomposition of CSI Part 2 - Method 2 A drawback of the above CSI decomposition method 1 shown in Figures 2 and 3 is that if all CSI subgroups associated with a single CSI report are dropped, the complete CSI report is dropped. In order to avoid dropping the complete CSI content of a CSI report, the following embodiment supports the gNB to drop all N CSI subgroups even if all CSI subgroups are dropped by the UE except for the first CSI subgroup with priority level 0, which is the highest priority. REP We propose a CSI decomposition that allows partial recomputation of the CSI matrix for CSI subgroups.

[0094] According to an embodiment, N REP CSI part 2 of this CSI report is TN REP +1 CSI subgroups, where T CSI subgroups are always associated with a CSI report. The first subgroup of CSIs includes all N REP Contains information associated with this CSI report.

[0095] Each CSI subgroup is associated with a priority level, with the first subgroup having the highest priority level 0. REP CSI subgroups have lower priority levels 1 to TN REP Associated with the last CSI subgroup TN REP is the lowest priority level TN REP It is associated with.

[0096] The parameter T indicates the number of CSI subgroups per CSI report and relates to the granularity of the CSI content omitted from the CSI report. A high value of T indicates high granularity and a low value of T indicates low granularity. If the parameter T is given a value of 2, each CSI report is associated with only two CSI subgroups.

[0097] The parameter T, which indicates the number of CSI subgroups per CSI report, may also depend on the CSI report. In one example, the parameter T may depend on the rank indicated in the CSI report. For example, if the rank indicated in the CSI report is greater than 1, i.e., RI>1, then T=2, and if the rank indicated in the CSI report is 1, i.e., RI=1, then T=1. In another example, the parameter T may depend on the number of non-zero coefficients K indicated in the CSI report. NZ For example, the number of non-zero coefficients indicated in the CSI report may depend on the number of

[0098]

number

[0099] FIG. 4 shows a first example of scheme 2, in which priority levels (n-1)T+1 to nT (1≦n≦N REP ), and the T CSI subgroups associated with a single CSI report are always grouped together.

[0100] FIG. 5 shows a second example of scheme 2. In FIG. 5, priority level (t-1)N REP +1 to tN REP (1≦t≦T), and N REP N CSI reports associated with REP The CSI subgroups are always grouped together.

[0101] CSI Subgroup Contents According to an embodiment, the first CSI subgroup associated with the highest priority level 0 is REPWhen including CSI information for the CSI reports, the joint CSI subgroup may include at least one of the following parameters: - the selected SD basis subset indicator, including the rotational oversampling factor, if set, - selected DD basis subset indicators for the RI layer, - SCI in the RI layer, - the polarization reference amplitude value of the RI layer, - K in RI layer NZ a bitmap indicating non-zero coupling coefficients; - Additional possible parameters associated with the DD Basis Subset directive.

[0102] N in Method 2 REP For segmenting the phase and amplitude values ​​of the CSI reports, two partitioning techniques are proposed below. In the first method, N REP A first portion of the phase and amplitude values ​​of the selected non-zero delay-domain combining coefficients of the CSI report are included in a first joint CSI subgroup having the highest priority. An example of the CSI content of the first joint CSI subgroup for the first approach and the CSI subgroup having the highest priority and associated with a single CSI report is shown in FIG.

[0103] In the second approach, the first CSI subgroup with the highest priority is N REP The CSI report does not include any phase and amplitude values ​​of the selected non-zero delay-domain combining coefficients of the CSI report, and only the remaining CSI subgroups include information of the non-zero combining coefficients. An example of the CSI content of the first joint CSI subgroup and the CSI subgroups associated with a single CSI report for the second approach is shown in FIG.

[0104] In some examples, T=2 and there are only two groups per CSI report. Group 1, which is the subgroup with the highest priority per CSI report other than the joint CSI subgroup, is

[0105]

number

[0106]

number

[0107]

number

[0108]

number

[0109] UE is N for decomposition method 1 REPIf the gNB is configured to split the CSI payload of a CSI report and the UE drops up to T-1 CSI subgroups associated with a single CSI report, the gNB should still be able to recalculate a portion of the CSI matrix of the RI layer based on the remaining non-dropped CSI subgroups associated with that CSI report. In this way, a certain minimum performance can be guaranteed even when most of the CSI content of a CSI report is dropped. To recalculate a portion of the CSI matrix from the CSI report, the gNB may receive from the CSI report the selected SD and DD basis subset indicators, the SCI, the bitmap, and the polarization reference amplitude value of the RI layer, the window parameter M init At least some parameters need to be known, such as: This information must be included in each CSI report in the CSI subgroup with the highest priority.

[0110] According to an embodiment, N REP If the CSI payload containing the CSI information of a CSI report is divided into several CSI subgroups, and each CSI subgroup contains CSI information associated with only a single CSI report, the CSI subgroup with the highest priority of the CSI report may contain information of at least the following parameters: - the selected SD basis subset indicator, including the rotated oversampling factor, if set; - selected DD basis subset indicators for the RI layer, - SCI in the RI layer, - the polarization reference amplitude value of the RI layer, - K in RI layer NZ a bitmap indicating non-zero coupling coefficients; - Additional possible parameters associated with the DD Basis Subset directive.

[0111] In order to divide the amplitude and phase values ​​into CSI subgroups, several methods are proposed below. In a first method, the CSI subgroup with the highest priority per CSI report does not include any information of the selected non-zero coupling coefficient, and only the remaining T-1 CSI subgroups with lower priority include the amplitude and phase values ​​of the selected non-zero coupling coefficient of the CSI report. In a second method, the CSI subgroup with the highest priority per CSI report may include information of a first portion of the amplitude values ​​of the selected non-zero delay-domain coupling coefficient, and the remaining T-1 CSI subgroups with lower priority include the remaining portions of the amplitude values ​​and all phase values ​​of the CSI report. In a third method, the CSI subgroup with the highest priority per CSI report may include information of a first portion of the amplitude and phase values ​​of the selected non-zero delay-domain coupling coefficient, and the remaining T-1 CSI subgroups with lower priority include the remaining portions of the amplitude and phase values ​​of the CSI report.

[0112] FIG. 8 shows the CSI content of two CSI subgroups associated with a single CSI report and the corresponding CSI content of each CSI subgroup when splitting the amplitude and phase values ​​for the third method.

[0113] For UCI omission and CSI splitting as shown in Figure 2, the UE first drops the CSI subgroups that contain CSI information associated with non-zero combining coefficients. The remaining CSI subgroups still contain CSI content that can be used to partially recalculate the CSI matrix represented in the CSI report. Only if the UE drops all T CSI subgroups associated with a CSI report is the complete CSI report dropped.

[0114] For UCI omission and CSI splitting as shown in Figure 3, the UE first drops the CSI subgroups containing CSI information related to the non-zero delay domain combining coefficients of the CSI report with the lowest priority. If the UE drops all T CSI subgroups associated with the CSI report with the lowest priority, the complete CSI report is dropped.

[0115] According to an embodiment, each CSI subgroup containing information of a portion of the coupling coefficients may include up to

[0116]

number

[0117] For example, for T=2 and x=2 and group 1, the CSI subgroup with the highest priority per CSI report other than the joint CSI subgroup is

[0118]

number

[0119]

number

[0120]

number

[0121]

number

[0122]

number

[0123]

number

[0124] In the proposed scheme 1, one or more bitmaps of the RI layer of a CSI report are included in the first CSI subgroup with the highest priority. Therefore, the payload size of this CSI subgroup can be larger than the payload size of the other CSI subgroups. If the UCI drop rate is high due to the larger payload size, i.e., the UE needs to drop most of the contents of CSI part 2, the UE may drop the CSI subgroup containing the bitmaps and thus the complete CSI report in some cases.

[0125] Similarly, in proposed method 2, N REP All bitmaps of the RI layer of this CSI report may be included in the first joint CSI subgroup, or may be included per CSI report in the first CSI subgroup with the highest priority. The payload size of this / these CSI subgroups may be large, and the UE may in some cases drop the CSI subgroup containing the bitmap of the RI layer if the UCI drop rate is high.

[0126] The following embodiments propose various schemes to reduce the payload size of the CSI subgroups containing bitmaps by splitting the bitmaps as well as the phase and amplitude information of the combining coefficients into different CSI subgroups, thus reducing the probability of dropping this / these CSI subgroups.

[0127] Segmentation on DD basis subsets The first segmentation scheme divides the multiple bitmaps and multiple combining coefficients with respect to the number of DD basis vector indices of the CSI report.

[0128] When the UE drops a CSI subgroup, the CSI content of the remaining CSI subgroups with higher priority should allow the gNB to partially reconstruct the RI layer CSI matrix indicated in the CSI report. To do this, the gNB needs knowledge of the strongest combining coefficients per layer and associated SD and DD basis indices. This information can be obtained from the RI layer bitmap and SCI. To correctly interpret the SCI, the first joint CSI subgroup or the first CSI subgroup associated with a single CSI report should contain at least a portion of the bitmap and information of the combining coefficients associated with the DD basis vector indices of the SCI of the RI layer.

[0129] According to one embodiment, each CSI subgroup having the highest priority and associated with a single CSI report may include at least a bitmap associated with all SD components of one or more DD basis vectors or one or more DD basis vector indices of the RI layer of the CSI matrix indicated in the CSI report. In addition, the CSI subgroup may include corresponding amplitude and / or phase information of the combining coefficients of the RI layer of the CSI matrix.

[0130] The bitmap of the RI layer of the CSI subgroup and the corresponding amplitude and / or phase information of the coupling coefficients can be segmented into D' segments, where each segment includes one or more bitmaps of the RI layer associated with a single DD basis vector or DD basis vector index, and the corresponding amplitude and / or phase information of the coupling coefficients. Here, D' ≤ D, and D indicates the number of DD basis vectors set for the UE for each of the RI layers of the CSI matrix.

[0131] If D' < D in the CSI subgroup, the CSI subgroup with lower priority and / or the joint CSI subgroup, if it exists, may include the remaining DD basis vectors and the remaining segments associated with the DD basis vector indices.

[0132] According to one embodiment, each CSI subgroup having the highest priority and associated with a single CSI report may include a part of the coupling coefficient information associated with all SD components of the DD basis vector index associated with the bitmap and the SCI of the RI layer.

[0133] Example of segmentation According to one embodiment, the bitmap and the amplitude and / or phase information included in the CSI subgroup are segmented into one or more segments, where each segment may include a sub-bitmap that is a part of the bitmap for each of the RI layers, and the associated amplitude and / or phase information of the coupling coefficients associated with the sub-bitmap.

[0134] In the configuration example of T = 2, the CSI content of two CSI subgroups associated with a single CSI report is shown in FIG. 9. As observed from the figure, the sub-bitmap and the phase and amplitude information of the coupling coefficients associated with all SD components and DD basis vector indices of the RI layer are always packed together into a single segment.

[0135] It should be noted that the last segment of a CSI subgroup may include only a portion of the sub-bitmap or only a portion of the amplitude and / or phase information associated with that sub-bitmap. In such a case, the remaining portion of the sub-bitmap or the remaining portion of the amplitude and / or phase information associated with that sub-bitmap that is not included in the CSI subgroup may be included in a lower priority CSI subgroup of the same CSI report.

[0136] According to one embodiment, the bitmap and amplitude and / or phase information included in the CSI subgroup are segmented into one or more segments, where each segment may include a sub-bitmap that is a portion of the bitmap at each of the RI layers and associated amplitude and / or phase information for a combining coefficient associated with the sub-bitmap.

[0137] In one example, the kth segment is further segmented into RI sub-segments, where each sub-segment includes a sub-bitmap associated with all SD components and DD basis vector indices of a single layer, and a coupling coefficient associated with the sub-bitmap. See FIG. 10.

[0138] In one example, each subsegment k associated with the rth layer r As shown in Figure 11, k r,2U Each k r,u Each sub-segment contains a single bit from the sub-bitmap and the corresponding amplitude and phase information of the combining coefficient. r,u If is '0', then bit k r,u Subsegment k immediately follows r,u+1 This is followed by bit k r,u This is due to the lack of amplitude and phase information associated with

[0139] According to one embodiment, the RI layer bitmap and combining coefficient information of a CSI report is segmented into D segments, where each segment includes bitmaps associated with all SD components of a single DD basis index of all RI layers, i.e., sub-bitmaps. In addition, each segment may include associated amplitude and / or phase information of the combining coefficients of the RI layers associated with the sub-bitmaps. A CSI subgroup having the highest priority and associated with a single CSI report may include one or more of the D segments.

[0140] Each CSI subgroup with the highest priority may additionally include a set of parameters required from the CSI report such that the gNB may be able to recalculate the CSI matrix based on a portion of the RI layer bitmap, and amplitude and / or phase information of the combining coefficients included in the CSI subgroup.

[0141] According to one embodiment, N REP In the case where the CSI payload including the CSI information of the CSI report is decomposed into several CSI subgroups, each CSI subgroup including CSI information associated with only a single CSI report, and in addition, the UE is configured to perform segmentation of the amplitude and / or phase information of the bitmap and combining coefficients with respect to the DD basis vector index into CSI subgroups, each CSI subgroup with the highest priority may additionally include at least the following parameters: - selected SD basis subset indicator including rotational oversampling factor, - selected DD basis subset indicators for the RI layer, - SCI in the RI layer, - the polarization reference amplitude value of the RI layer, - Additional possible parameters associated with the DD Basis Subset directive.

[0142] According to an embodiment, N REPThe CSI payload including the CSI information of the CSI reports is decomposed into several CSI subgroups, and the first CSI subgroup is REP The joint CSI subgroup may include CSI information associated with the CSI report, and in addition, if the UE is configured to perform segmentation of amplitude and / or phase information of bitmap and combining coefficients with respect to DD basis vector index into CSI subgroups, the joint CSI subgroup may include at least the following parameters: - the selected SD basis subset indicator, including the rotated oversampling factor, if set; - selected DD basis subset indicators for the RI layer, - SCI in the RI layer, - the polarization reference amplitude value of the RI layer, - Additional possible parameters associated with the DD Basis Subset directive.

[0143] The remaining CSI subgroups include at least the CSI content associated with the RI layer bitmap and the phase and amplitude information of the combining coefficients. Each CSI subgroup having the highest priority and associated with a single CSI report includes at least a portion of the RI layer bitmap and K NZ The signal may include phase and amplitude information of a portion of the coupling coefficients.

[0144] In some examples, T=2 and group 1 is the group with index i 1,5 , if reported, i 1,6,l , i 1,7,l of

[0145]

number

[0146]

number

[0147]

number

[0148]

number

[0149] In some examples, T=2, and group 2 is i 1,7,l of

[0150]

number

[0151]

number

[0152]

number

[0153]

number

[0154]

number

[0155]

number

[0156] If the UE is implemented to perform a circular shift operation on the selected DD basis vectors per layer with respect to the DD basis vector index associated with the selected combining coefficient and SCI, after the circular shift operation, only the portion of the bitmap associated with all SD basis vectors and the first DD basis vector, DD basis vector index 0, is needed in each of the RI layers to identify the SD and DD basis index associated with the strongest combining coefficient. In order to correctly interpret the SCI, the first CSI subgroup should include the portion of the bitmap associated with DD basis vector index 0 and the combining coefficient information.

[0157] In addition, SCI

[0158]

number

[0159] According to one embodiment, when the UE is configured to perform, for a CSI report, a circular shift operation on the selected combining coefficients and selected DD basis vectors per layer with respect to a DD basis vector index associated with an SCI, the CSI subgroup with the highest priority associated with the CSI report includes the sub-bitmap associated with DD basis vector index 0 and corresponding amplitude and / or phase information of the combining coefficients associated with that sub-bitmap for the RI layer. For example, a first segment of the CSI subgroup with the highest priority may be associated with DD basis vector index 0.

[0160] If the UE is not implemented to perform a circular shift on the selected combining coefficients and selected DD basis vectors per layer with respect to the DD basis vector index associated with the SCI, a complete bitmap of all selected SD and DD basis vectors per layer may be required by the gNB to identify the SD and DD basis vector index associated with the strongest combining coefficient. Thus, the above segmentation of the bitmaps and combining coefficients with respect to the DD basis vector index may not be possible.

[0161] According to an embodiment, if the UE is not implemented to perform a circular shift operation on the layer-wise selected combining coefficients and the selected DD basis vectors with respect to the DD basis vector index associated with the SCI for a CSI report, a CSI subgroup of a CSI report with the highest priority may include at least the bitmap of the RI layer and all or a portion of the phase and / or amplitude information of the combining coefficients of the CSI matrix of the CSI report. If a CSI subgroup includes only a portion of the phase and / or amplitude information of the combining coefficients, the remaining CSI subgroups of CSI reports with lower priority may include the remaining portions of the phase and / or amplitude information of the combining coefficients of the CSI matrix.

[0162] According to one embodiment, the UE is not configured to perform a cyclic shift operation on the layer-wise selected combining coefficients and the selected DD basis vectors with respect to the DD basis vector index associated with the SCI for the CSI report, and N REP The CSI payload containing the CSI information of the CSI reports is REP When a CSI report is decomposed into several CSI subgroups constituting a joint CSI subgroup containing CSI information associated with the CSI report, the joint CSI subgroup may contain a bitmap of the RI layer of the CSI report.

[0163] Multi-layer segmentation The second segmentation scheme partitions, for a CSI report, the bitmap and combining coefficients for the RI layer of the CSI matrix indicated in the CSI report.

[0164] According to an embodiment, the CSI subgroup associated with the highest priority of the CSI report may include at least a bitmap indicating the non-zero combining coefficients of a first subset of the RI layer and a first portion of amplitude and phase values ​​of selected non-zero delay-domain combining coefficients associated with the first subset of the RI layer of the CSI matrix indicated in the CSI report.

[0165] The remaining CSI subgroup of lower priority associated with the same CSI report may include at least a bitmap of the second subset of the remaining RI layers and a remaining portion of the amplitude and phase values ​​associated with the second subset of the RI layers of the CSI report.

[0166] If the UE is configured to disassemble the CSI payload for scheme 1 above, the CSI subgroup with the highest priority per CSI report may additionally include the following parameters: - the selected SD basis subset indicator, including the rotated oversampling factor, if set; - a selected DD basis subset indicator of a first subset of the RI layer; - SCI of the first subset of the RI layer, - the polarization reference amplitude values ​​of the first subset of RI layers, - a bitmap indicating the non-zero coupling coefficients of a first subset of the RI layer; - Additional possible parameters associated with the DD Basis Subset directive.

[0167] If the UE is configured to disassemble the CSI payload for the above manner 2, the CSI subgroup with the highest priority per CSI report of the CSI report may additionally include the following parameters, if not already listed in the joint CSI subgroup: - selected DD basis subset indicators for the RI layer, - SCI in the RI layer, - the polarization reference amplitude value of the RI layer, - Additional possible parameters associated with the DD Basis Subset directive.

[0168] Wideband CSI information In 3GPP Release 15, the decomposition of CSI part 2 is performed by dividing the first CSI part with priority level 0 by N REPThe first CSI report includes so-called wideband amplitudes of the CSI reports. Based on these wideband amplitudes in the first CSI portion, the gNB can reconstruct the wideband CSI matrix of the configured subbands for each CSI report, even if the UE drops all but the first CSI portion with priority level 0. When applying the second CSI decomposition scheme described above, similar wideband CSI matrices can be defined for the two codebook-based CSI reporting schemes. The gNB may derive the wideband CSI matrix of the CSI report if it has knowledge of the amplitude information of the combining coefficients and a portion of the bitmap associated with the "strongest" DD basis vector index of each of the RI layers. In many cases, the "strongest" DD basis vector index per layer corresponds to the DD basis vector index associated with the SCI. Thus, based on the SCI, the bitmap associated with the DD basis vector index associated with the SCI, and the amplitude information of the combining coefficients, the gNB may reconstruct the wideband CSI matrix as proposed in the following embodiments.

[0169] According to one embodiment, N REP The CSI payload including the CSI information of the CSI reports is decomposed into several CSI subgroups, and the first CSI subgroup is REP In the case where the joint CSI subgroup includes CSI information associated with the CSI reports, the joint CSI subgroup may include the SCI of the RI layer, a portion of the bitmap, and amplitude and / or phase information of combining coefficients associated with all SD components of the DD basis vector indexes associated with the SCI of the RI layer of the one or more CSI reports. Based on the information included in the joint CSI subgroup, the gNB may recalculate the wideband CSI matrix for each of the one or more CSI reports.

[0170] Similar to the circular shift operation discussion above, if the UE is configured to perform a circular shift operation on the selected DD basis vectors per layer with respect to the DD basis vectors associated with the selected combining coefficients and SCI for the CSI report, then DD basis vector index 0 is associated with the SCI.

[0171] According to one embodiment, N REP The CSI payload including the CSI information of the CSI reports is decomposed into several CSI subgroups, and the first CSI subgroup is REP In the case where the joint CSI subgroup includes CSI information associated with a CSI report, the joint CSI subgroup may include, for one or more CSI reports, the SCI of the RI layer, a portion of the bitmap, and amplitude and / or phase information of the combining coefficients associated with all SD components of the RI layer and DD basis vector index 0 for each CSI report.

[0172] Furthermore, as discussed above, if the UE is not implemented to perform a circular shift operation on the selected combining coefficients for a CSI report, then a complete bitmap of all selected SD and DD basis vector indices per layer and amplitude and / or phase information of the combining coefficients associated with the DD basis vector indices associated with the SCIs of at least the RI layer are required for the computation of the wideband matrix for that CSI report.

[0173] According to one embodiment, N REP The CSI payload including the CSI information of the CSI reports is decomposed into several CSI subgroups, and the first CSI subgroup is REPIn the case where the UE includes CSI information associated with a CSI report and the UE is not implemented to perform a circular shift operation on the selected combining coefficients of the CSI report, the joint CSI subgroup may include a complete bitmap of all selected SD and DD basis vector indices per layer and at least the amplitude and / or phase information of the combining coefficients associated with the DD basis vector index associated with the SCI of the RI layer of that CSI report.

[0174] The size of the joint CSI subgroup depends on the number of nonzero combining coefficients associated with the DD basis vector index of the SCI of one or more CSI reports. Therefore, the gNB may not know the payload size of the joint CSI subgroup even after decoding of CSI part 1 of the CSI payload. Below, a method for fixing the payload size of the joint CSI subgroup is presented.

[0175] According to one embodiment, the joint CSI subgroup includes at least the SCI of the RI layer, a portion of the bitmap, and amplitude and / or phase information of the combining coefficients associated with all SD components and DD basis vector indices of the SCI of the RI layer in the N CSI reports with highest priority.

[0176] The value of the parameter N may be higher layer set by the gNB, may be known in advance by the UE, e.g., fixed by a specification, or may be determined by the UE. For example, the UE may determine the value of the parameter N, i.e., the number of CSI reports with the highest priority, such that the payload size of the joint CSI subgroup is fixed.

[0177] Reading / packing rules when RI layer bitmaps are in a single CSI subgroup As explained above, the CSI subgroup having the highest priority and associated with a single CSI report may include bitmaps of all RI layers and only a portion of the phase and / or amplitude information of the combining coefficients.

[0178] The following embodiments present a decomposition scheme of the phase and / or amplitude information of the combining coefficients with respect to the number of CSI subgroups. The decomposition of the phase and / or amplitude information of the combining coefficients may depend on the ordering of the bit sequences of the associated bitmap of the RI layer of the CSI report.

[0179] According to an embodiment, if all RI layer bitmaps of size 2UD×RI associated with a single CSI report are included in a single CSI subgroup, the bitmap is segmented into RI segments, each of the 2UD bits in ascending order with respect to the layer number. Each segment is associated with all the SD and DD base indices of the layer. See FIG. 12. In case of UCI omission, the UE first drops CSI content associated with one or more of the higher layers, and then drops CSI content associated with one or more of the lower layers. For example, if RI=4 and T=2, the UE may first drop CSI content associated with the CSI subgroups of layers 3 and 4, which have lower priority, and then drop CSI content associated with the CSI subgroups of layers 1 and 2, which have higher priority of the CSI report.

[0180] The bit sequence within each segment may be ordered with respect to one of the following two schemes: In a first ordering scheme (Scheme 1), the bits within each segment of size 2UD×1 are ordered such that the first 2U bits are associated with all 2U SD components of the first DD basis index, followed by 2U bits associated with all 2U SD components of the second DD basis index, and so on. See Figure 13. In a second ordering scheme (Scheme 2), the bits within each segment of size 2UD×1 are ordered such that the first D bits are associated with all D DD basis indexes of the first SD basis index, followed by D bits associated with all D DD basis indexes of the second SD basis index, and so on. See Figure 14 or Figure 15.

[0181] When the bitmaps are ordered as shown in Figure 13, Figure 14, or Figure 15, the portion of the phase and / or amplitude information of the combining coefficients included in a CSI subgroup is always associated with only a subset of the RI layers of the CSI report. Such ordering / packing may lead to a large performance loss compared to dropping only the portion of the phase and / or amplitude information of the combining coefficients of all RI layers. The following embodiments present alternative ordering / segmentation of the bitmaps and combining coefficients that avoid dropping the combining coefficients of one or more layers of the CSI report.

[0182] According to an embodiment, when a CSI subgroup includes bitmaps of all RI layers, the bitmap of size 2UD×RI is segmented into D segments, each segment having size 2U×RI and associated with a single DD basis vector index. See FIG. 16. In case of UCI omission, the UE first drops CSI content associated with one or more DD basis indices of all RI layers, and then drops CSI content associated with the remaining DD basis indices of all RI layers. For example, in case of D=4, the UE may first drop CSI content associated with DD basis indices 3 and 4, and then drop CSI content associated with DD basis indices 1 and 2 of the CSI report.

[0183] The bit sequence within each segment may be ordered with respect to one of the following two schemes: In a first ordering scheme (Scheme 1), the bits within each segment of size 2U×RI are ordered such that the first RI bit is associated with the first SD basis vector index of all RI layers, followed by the next RI bit associated with the second SD basis index of all RI layers, and so on. See Figures 17 and 18. In a second ordering scheme (Scheme 2), the bits within each segment of size 2U×RI are ordered such that the first 2U bits are associated with all 2U SD components of the DD basis index associated with the first layer, followed by 2U bits associated with all 2U SD components of the DD basis index associated with the second layer, and so on. See Figure 19.

[0184] Packing / ordering rules for coupling coefficients As described in one embodiment, a CSI subgroup associated with a CSI report may include amplitude and phase information for a portion of the combining coefficients, where a different ordering scheme of the amplitude and phase values ​​may be applied.

[0185] According to one embodiment, the amplitude and phase information of the multiple combining coefficients in a CSI subgroup may be ordered according to one of the following schemes: In scheme 1, for each combining coefficient in a CSI subgroup, a bits of amplitude information are followed by b bits of phase information, see FIG. 20, where X denotes the number of combining coefficients included in the CSI subgroup; In scheme 2, Xa bits of amplitude information for the X combining coefficients are followed by Xb bits of phase information for the X combining coefficients, see FIG. 21; In scheme 3, Xb bits of phase information for the X combining coefficients are followed by Xa bits of amplitude information for the X combining coefficients, see FIG. 22.

[0186] In one example, in the CSI subgroup having the highest priority for each CSI other than the joint CSI subgroup,

[0187]

number

[0188]

number

[0189]

number

[0190]

number

[0191]

number

[0192]

number

[0193]

number

[0194] Extending the ordering rules: The CSI subgroup having the highest priority and associated with a single CSI report may contain all RI layer bitmaps and only a portion of the CSI content associated with the combining coefficients and phase and amplitude information of the CSI report. In the following, various decomposition schemes of the combining coefficients and associated CSI content of the CSI report for a CSI subgroup are proposed.

[0195] It is assumed that the ordering of the phase and amplitude information of the combining coefficients matches the ordering of the bit sequences associated with all RI layer bitmaps. DD base index sorting: According to an embodiment, the UE is configured to segment the l-th layer bitmap into D bit sequences for a selected DD basis index, with each segment having a size of 2U×1. Thus, the l-th layer bitmap is

[0196]

number

[0197]

number

[0198] In an exemplary embodiment, the DD basis index e of the bitmap of the lth layer l,d and the associated coupling coefficients are sorted in ascending order, i.e., e l,0 <... <e l,d <... <e l,D-1 For example, if the selected DD basis index is given by [0, 21, 2, 25], then the DD basis index is [e l,0 ,e l,1 ,e l,2 ,e l,3 ]=[0,2,21,25], and the corresponding bitmaps are B0,B2,B 21 ,B 25 is given by:

[0199] FIG. 23 shows a first scheme illustrating the ordering of DD basis indices starting with DD basis index 0, followed by right DD index 1, then left DD index 25, and so on for a delay codebook size N3=26.

[0200] FIG. 24 shows a second scheme illustrating the ordering of DD base indices starting with DD base index 0 for N3=26, followed by DD index 25 on the left, followed by DD index 1 on the right, and so on.

[0201] DD basis index 0 is associated with the strongest combining coefficient and therefore carries a significant amount of the power of the combining coefficients of the precoder. Thus, the power of the DD basis index selected by the UE is attenuated with respect to DD basis index 0. This means that a significant amount of power is associated with DD basis index 0, followed by adjacent DD basis indexes with less power. In case of UCI omission, the UE shall first drop the combining coefficients with less power, which implies that the selected DD basis indexes should be ordered with respect to descending power. Figures 23 and 24 show two ordering schemes in the case of N3 DD basis indexes (0, . . . , N3-1), where N3 denotes the number of DD basis indexes in the delay codebook.

[0202] In the first scheme shown in FIG. 23, the N3 DD basis indexes are: 0,1,N3-1,2,N3-2,3,N3-3,4,N3-4,5,... are ordered as

[0203] In the second scheme shown in FIG. 24, the N3 DD basis indexes are: 0,N3-1,1,N3-2,2,N3-3,3,N3-4,4,N3-5,5,... are ordered as

[0204] According to an embodiment, the UE is configured to order the selected DD basis indexes for each layer according to the first or second scheme, as shown in Figure 23 and Figure 24, respectively. For example, when N3=26 and the selected DD basis indexes for the l-th layer are given by [0,2,21,24] or [0,1,2,22,23,24], and the first scheme is applied, the DD basis indexes are ordered as [e l,0 ,e l,1 ,e l,2 ,e l,3 ]=[0,2,24,21] or [e l,0 ,e l,1 ,e l,2 ,e l,3 e l,4 ,e l,5 Similarly, if the selected DD basis index is given by [0,2,21,24] or [0,1,2,22,23,24] and the second scheme is applied, the DD basis index is given by [e l,0 ,e l,1 ,e l,2 ,e l,3 ]=[0,24,2,21] or [e l,0 ,e l,1 ,e l,2 ,e l,3 e l,4 ,e l,5 ]=[0,1,24,2,23,22].

[0205] In some examples, the ordering of the selected DD basis indices of all layers according to the second ordering scheme is achieved by the following equation, which is a function of the layer index l, the selected D DD basis indices, and the size of the delay codebook N3:

[0206]

number

[0207] Therefore, the bitmap for the lth layer is

[0208]

number

[0209]

number

[0210] According to an embodiment, when a CSI subgroup includes a bitmap of size 2UD×RI, i.e., bitmaps of all RI layers, the bit sequences of the bitmaps of the layers can be ordered with respect to the first or second scheme. The corresponding ordered bitmaps of the RI layers can be grouped together into a bitmap of size 2UD×RI and segmented into D segments, where each segment has size 2U×RI. See FIG. 16. Thus, the bitmap is

[0211]

number

[0212]

number

[0213]

number

[0214] Spatial beam indices u and U+u are associated with beam u (SD basis index), and beam u is associated with a SD index selected from the codebook. For example, if U=2 and the selected SD index is [1,3], then spatial beam indices 0 and 2 are associated with SD index 1, and spatial beam indices 1 and 3 are associated with SD index 3.

[0215] Index of one polarization of the lth layer, g l,u and the index of the other polarization g l,U+u An example of mapping of spatial beam index (u=0, . . . , 2U-1) to the u-axis for U=4 is shown in FIG.

[0216] The third ordering method In the third scheme, the beam indices of the two polarizations of the spatial beam and associated segments A dThe bits in are grouped together and sorted with respect to increasing layer index. This means that the two polarizations of the uth spatial beam in the first layer, i.e., spatial beam index g l,u and g l,U+u The two bits associated with and are grouped together, and then the two polarizations of the same spatial beam in the second layer, i.e., the spatial beam index g l,u and g l,U+u Then, the two bits associated with segment A follow, and so on. For example, if RI=4, then segment A d teeth

[0217]

number

[0218] The fourth ordering method In the fourth ordering scheme, the polarization of the spatial beams in all layers is associated with segment A. d The bits in are grouped together and sorted with respect to increasing layer index. This is done by sorting the spatial beam index (g l,u ) are grouped together, followed by the second polarization of the same spatial beam index (g l,U+u ) followed by the RI bit associated with the segment A. For example, if RI=4, then segment A d teeth

[0219]

number

[0220] Fifth Ordering Scheme In the fifth ordering scheme, all layers are associated with the same spatial beam index and segment A d The bits in are grouped together and sorted with respect to increasing layer index. This is done by sorting the spatial beam index (g l,u ) and associated RI bits are grouped together and then assigned another spatial beam index (g l,U+1 ) followed by the RI bit associated with the segment A. For example, if RI=4, then segment A d teeth

[0221]

number

[0222]

number

[0223] According to an embodiment, the UE is configured to order the bit sequences and combining coefficients of the bitmap according to one of the first and second ordering schemes in combination with the third, fourth, fifth and sixth ordering schemes.

[0224] In some examples, the combining or joint ordering of the bit sequences of the bitmap according to the second ordering scheme and the fifth ordering scheme is based on the following formula:

[0225]

number

[0226]

number

[0227] The ordering of the amplitude and phase information of the combining coefficients shall be consistent with the ordering of the bits in the bitmap. Beam index reordering: Each spatial beam is associated with up to D non-zero coupling coefficients. The sum of the powers of the coupling coefficients of the spatial beam associated with the strongest coefficient may be high compared to the sum of the powers of the coupling coefficients associated with the other spatial beams. Thus, in case of UCI omission, the bitmap associated with the strongest spatial beam, i.e., the beam associated with SCI, should have a higher priority than the bitmaps associated with the other spatial beams and should therefore be ordered first, followed by the bitmaps of the other spatial beams. Hereinafter, the index g, which is the spatial beam index, l,u and g l,U+u We present various reordering methods for

[0228] In one exemplary embodiment, as shown in FIG. l,u , ∀u=0,···,2U-1 to the spatial beam index u,∀u=0,···,2U-1 and segment A d Indicates a direct mapping of the bitmap associated with

[0229] In another exemplary embodiment, the bit from the bitmap associated with the spatial beam associated with the strongest coefficient of the lth layer is denoted by index g l,0 For the mapping of the remaining 2U-1 indexes, polarization common mapping or polarization specific mapping may be considered. In polarization common mapping, the mapping for the two polarizations of the spatial beam is identical, while in polarization specific mapping, the mapping is done regardless of the polarization of the spatial beam, resulting in different mapping for the two polarizations. Examples of polarization common mapping and polarization specific mapping schemes are described in more detail below.

[0230] Polarization common mapping: An example of a co-polarized mapping of bits associated with 2U beams, two polarizations and segments, is shown in Figures 27 to 30. The bits associated with the spatial beam associated with the strongest coefficient are marked with a dashed red line. The bits associated with the same spatial beam in the other polarization are marked with a solid red line.

[0231] FIG. 27 shows the strongest coefficient when U=4 and associated with the first polarization, with index g l,u , which shows the mapping of bits associated with spatial beam index u,∀u=0,···,2U−1 to ∀u=0,···,2U−1.

[0232] In the mapping scheme shown in Figure 27, the spatial beam index u associated with the strongest coefficient SCI In the example, u SCI = 2 is the first index g l,0 The spatial beam index (u SCI -1) is the next index g l,1 and the following expression:

[0233]

number

[0234]

number

[0235] FIG. 28 shows the strongest coefficient U=4 and associated with the first polarization, with index g l,u , which shows the mapping of bits associated with spatial beam index u,∀u=0,···,2U−1 to ∀u=0,···,2U−1.

[0236] In the mapping scheme shown in Figure 28, the spatial beam index u associated with the strongest coefficient SCI (In the example, SCI =2) is the first index g l,0 The spatial beam index (u SCI +1) is the next index g l,1 and the following expression:

[0237]

number

[0238]

number

[0239] FIG. 29 shows the strongest coefficient when U=4 and associated with the second polarization, with index g l,u , which shows the mapping of bits associated with spatial beam index u,∀u=0,···,2U−1 to ∀u=0,···,2U−1.

[0240] In the mapping scheme shown in Figure 29, the spatial beam index (U + u SCI ) is the first index g l,0 and the spatial beam index (U+u SCI -1) is the next index g l,1 and the following expression:

[0241]

number

[0242]

number

[0243] FIG. 30 shows the strongest coefficient when U=4 and associated with the first polarization, with index g l,u , which shows the mapping of bits associated with spatial beam index u,∀u=0,···,2U−1 to ∀u=0,···,2U−1.

[0244] In the mapping scheme shown in Figure 30, the spatial beam index (U+u SCI ) is associated with the strongest coefficient, and the first index g l,0 and the spatial beam index (U+u SCI +1) is the next index g l,1 and the following expression:

[0245]

number

[0246]

number

[0247] Polarization Specific Mapping: Regardless of the relationship of the strongest coefficient to the polarization, the spatial beam index u,∀u=0,···,2U-1 index is denoted by the index g l,0 ,···,g l,2U-1 Two mapping possibilities are presented below to map σ to σ. Examples of such mappings are presented in Figures 31 and 32. The bits associated with the spatial beam associated with the strongest coefficient are shown in a dashed red box.

[0248] Figure 31 shows the index g l,u , which shows the mapping of the bitmap associated with spatial beam index u,∀u=0,···,2U−1 to ∀u=0,···,2U−1.

[0249] In the mapping scheme shown in Figure 31, the spatial beam index u associated with the strongest coefficient SCI (In the example, SCI =2) is the first index g l,0 and the spatial beam index (u SCI -1) is the next index g l,1 and the following expression:

[0250]

number

[0251] Figure 32 shows the index g l,u , ∀u=0,···,2U−1 to the spatial beam index u, ∀u=0,···,2U−1, and the associated bitmap is shown.

[0252] In the mapping scheme shown in Figure 32, the spatial beam index u associated with the strongest coefficient SCI (In the example, SCI =2) is the first index g l,0 and the spatial beam index (u SCI +1) is the next index g l,1 and the following expression:

[0253]

number

[0254] According to an embodiment, the CSI subgroup of the CSI report with the highest priority or the joint CSI subgroup (priority level 0) includes the bitmaps of all RI layers of the CSI report.

[0255]

number

[0256]

number

[0257]

number

[0258] Bitmap and coefficient segmentation enhancements: The segmentation scheme described above divides the bitmaps and combining coefficients with respect to the number of configured delays (D) per layer of the CSI report, see Figure 9. Each segment contains bitmaps and combining coefficients associated with 2U spatial beam indices and RI layers.

[0259] According to an embodiment, each segment may be further segmented into R′ sub-segments, where each sub-segment includes a sub-bitmap of R bits and combining coefficients associated with the R bits, and the bits in each sub-bitmap and combining coefficients in each segment are ordered according to a third, fourth, fifth, or sixth ordering scheme.

[0260] In one example, a third ordering scheme is applied, where each segment is further segmented into R′=U sub-segments, where each sub-segment can be associated with all RI layers and two polarizations of the spatial beam, and includes a sub-bitmap segment of R=2 RI bits and associated non-zero coupling coefficients.

[0261] In another example, a fourth ordering scheme is applied, where each segment is further segmented into R′=2U subsegments, where each subsegment may be associated with one polarization of all RI layers and spatial beams, and includes R=a bitmap segment of RI bits and associated non-zero coupling coefficients.

[0262] In another example, a fifth ordering scheme is considered, where each segment is further segmented into R′=2U sub-segments, where each sub-segment may be associated with all RI layers and includes sub-bitmap segments of R=RI bits and associated non-zero combining coefficients.

[0263] In some examples, the combination of ordering the bit sequences of the bitmap according to the second ordering scheme and the fifth ordering scheme is based on the following formula:

[0264]

number

[0265]

number

[0266] In another example, a sixth ordering scheme is considered, where each segment is further segmented into R′=RI segments, where each sub-segment may be associated with a layer and includes a sub-bitmap segment of R=2U bits and associated non-zero combining coefficients.

[0267] If the CSI subgroup size associated with a CSI report is fixed, then the parameter R defines the packing density of the combining coefficients. The smaller the value of R, the more combining coefficients can be packed into the CSI subgroup with the highest priority. In one case, R=2U or R=U. In another case, R=RI or R=2RI. In another case, R=1 and each subsegment contains a single bit and an associated nonzero combining coefficient if the single bit is given a value of "1", and in other cases, it contains only a single bit and no nonzero combining coefficients.

[0268] According to an embodiment, if the bitmaps of all RI layers are placed in the CSI subgroup with the highest priority, the ordering of the bitmaps can be different from the ordering of the combining coefficients, however, the ordering of the bitmaps and the combining coefficients shall be known a priori to the gNB.

[0269] CSI subgroup bit width According to an embodiment, the bit width of the first CSI subgroup associated with a single CSI report and with the highest priority may be fixed and may be given by A+B, where A is the combined bit width of all components included in the first subgroup apart from the number of non-zero combining coefficients, and B is the combining coefficient

[0270]

number

[0271]

number

[0272]

number

[0273]

number

[0274]

number

[0275]

number

[0276]

number

[0277]

number

[0278]

number

[0279]

number

[0280] [Table 1] According to an embodiment, the UE comprises:

[0281]

number

[0282] To carry out the above-mentioned method steps and UE operations, FIG. 3 Also provided is a UE 30, as shown in FIG. 3, comprising a processor 31, processing circuitry, processing module, processor, or means; a receiver circuit or module 34; a transmitter circuit or module 35; a memory module 32; and a transceiver circuit or module 33, which may include the transmitter circuit 35 and the receiver circuit 34. The UE 30 further comprises an antenna system 36 including at least antenna circuitry for transmitting signals to and receiving signals from the UE 30.

[0283] The present invention also relates to a computer program product 37, which is stored in the memory module 32 in the figure, and which comprises computer program code 38 which, when executed by the processor 31, enables the processor 31 to carry out any one of the subject matter of the methods of the present invention.

[0284] References [1] 3GPP TS 38.214 V15.3.0: “3GPP;TSG RAN;NR;Physical layer procedures for data (Rel.15),” September 2018. [2] Samsung, Revised WID: Enhancements on MIMO for NR, RP-182067, 3GPP RAN#81, Gold Coast, Australia, September 10-13, 2018. [3] R1-1806124, Fraunhofer IIS, Fraunhofer HHI, Enhancements on Type-II CSI reporting scheme, RAN1#93, Busan, Korea, May 21-25, 2018. [4] R1-1811088, Fraunhofer IIS, Fraunhofer HHI, Enhancements on Type-II CSI reporting scheme, RAN1#94-Bis, Chengdu, China, October 8-12, 2018. [5] Chairman's Notes, RAN1#96, Athens, Greece, February 25-March 1, 2019 [6] R1-1902304, Samsung, Summary of CSI enhancement for MU-MIMO, RAN1#96, February 25-March 1, 2019 [7] R1-1905629, Samsung, Feature lead summary for MU-CSI-revision on selected issues, Xi'an, China, April 12-16, 2019.

Claims

1. 1. A method performed by a user equipment (UE) providing channel state information (CSI) feedback in the form of one or more CSI reports in a wireless communication system (A), comprising: receiving, from a network node (gNB), higher layer configurations of one or more downlink reference signals, one or more CSI report configurations associated with the one or more downlink reference signal configurations, and a wireless signal, the wireless signal including the one or more downlink reference signals in accordance with the one or more downlink reference signal configurations, the one or more downlink reference signals being provided via a configured number of frequency domain resources, time domain resources, and one or more ports; For each CSI report, the one or more downlink reference signals and two codebooks, a spatial codebook including one or more spatial domain (SD) basis components of the precoder; and determining a precoding matrix based on the two codebooks, including a delay codebook including one or more delay-domain (DD) basis components of the precoder, and one or more non-zero combining coefficients that complex combine the one or more SD and DD basis vectors; reporting the one or more CSI reports of the one or more CSI report configurations to the network node; Each CSI report includes the selected precoding matrix in the form of a precoding matrix identifier (PMI) and a rank identifier (RI), the rank identifier (RI) indicating the transmission rank of the RI layer of the precoding matrix, each CSI report includes two parts, a CSI part 1 and a CSI part 2, CSI part 1 having a fixed payload size and including information indicating the size of the payload of CSI part 2, CSI part 2 including at least amplitude and phase information of the selected non-zero coupling coefficients and a bitmap of all RI layers indicating the non-zero coupling coefficients of the CSI report, the bitmap of each layer being segmented into D bit sequences with respect to DD basis indexes of the selected DD basis vectors, each bit sequence including 2U×1 bits associated with 2U spatial beams, U indicating the number of SD basis vectors selected from the spatial codebook, each DD basis index being associated with a delay vector from the delay codebook, the D bit sequences being N ３ The N DD base indexes are ordered with respect to one of two ordering schemes, where ３ denotes the number of DD basis indices of the delay codebook, and N ３ The DD basis indices are ordered as 0, 1, N according to the first ordering scheme. ３ -1, 2, N ３ -2, 3, N ３ -3, 4, N ３ -4, 5, ..., or ３ The DD basis indices are ordered from 0 to N according to the second ordering scheme. ３ −1, 1, N ３ -2, 2, N ３ -3,3,N ３ −4, 4, N ３ -5, 5, ..., the ordering of the amplitude and phase information of the combining coefficients following the order of the bit sequences of the bitmaps of all RI layers, and part or all of CSI part 2 is available for omission from the CSI report.

2. The number of CSI reports is N REP , and N ＲＥＰ CSI part 2 of this CSI report is TN ＲＥＰ +1 CSI subgroups, where T CSI subgroups are always associated with a single CSI report, and one CSI subgroup is associated with all N ＲＥＰ 2. The method of claim 1, further comprising: providing information associated with each CSI subgroup, the information including a CSI report associated with each CSI subgroup, the CSI subgroup being associated with a priority (priority level).

3. All N ＲＥＰ The CSI subgroup containing information associated with the CSI reports has the highest priority (priority level 0), and the remaining TN ＲＥＰ The CSI subgroups are of lower priority levels 1 to TN ＲＥＰ and the last CSI subgroup TN ＲＥＰ is the lowest priority level TN ＲＥＰ The method of claim 2 , wherein

4. The method of claim 2 or 3, wherein when a CSI subgroup of a particular priority level is omitted, the UE omits all the CSI content of that priority level.

5. 5. The method of claim 1, wherein the corresponding ordered bitmaps of the RI layers are grouped together into a bitmap of size 2UD×RI and segmented into D segments, each segment having size 2U×RI, and the dth segment is associated with 2U SD components of all RI layers.

6. 6. The method of claim 5, wherein bits in a bit segment associated with the same SD base index for all layers are grouped together and sorted with respect to ascending layer index, with RI bits associated with a first SD base index grouped together, followed by RI bits associated with a second SD base index, and so on.

7. Ordering the DD basis indexes for each layer according to the second ordering scheme comprises the steps of: [0010] where l=1, 2, ..., v, and f=0, 1, ..., D-1; [0025] 2. The method of claim 1 , wherein f is the fth DD basis index from the D DD basis indexes of each layer, and v is the total number of layers.

8. The ordering of the bits in the bitmap is determined by the formula: [0030] This is achieved by: [0045] , where l = 1, 2, ..., v, i = 0, 1, ..., 2U-1, and f = 0, 1, ..., D-1, where v is the total number of layers, U is the number of selected SD basis vectors per polarization, and D is the number of DD basis indices; [0050] is the fth DD basis index from the D DD basis indexes of each layer, The method according to any one of claims 1 to 7.

9. The CSI subgroup having the highest priority is RI=ν layer of the bitmap [006] highest priority elements; and [0070] highest priority amplitude values; [0080] highest priority phase values; K NZ is the number of non-zero coupling coefficients for the RI layer; The method according to claim 2 or 3.

10. The method of claim 2 or 3, wherein each CSI sub-group associated with a single CSI report comprises the amplitude and phase information of the coupling coefficients associated with a portion of the bitmap of the RI layer.

11. 4. The method of claim 2 or 3, wherein each CSI subgroup having the highest priority associated with a single CSI report includes at least a portion of the bitmap and the information of the combining coefficients associated with the DD basis index of a strongest coefficient indicator (SCI) of the RI layer.

12. For the CSI subgroup having the highest priority per CSI report, [0090] After the highest priority bit, there is a [0010] followed by the highest priority bit, where v is the total number of transmission layers, The method of any one of claims 9 to 11, wherein K NZ is the number of non-zero combining coefficients for the RI layer, a is the number of bits that are amplitude information for each combining coefficient of the CSI subgroup, and b is the number of bits that are phase information for each combining coefficient of the CSI subgroup.

13. A method performed by a network node (gNB) receiving one or more channel state information (CSI) feedback in the form of CSI reports in a wireless communication system (A), the method comprising: transmitting, to a user equipment (UE), higher layer configurations of one or more downlink reference signals, one or more CSI report configurations associated with the one or more downlink reference signal configurations, and a wireless signal, the wireless signal including the one or more downlink reference signals in accordance with the one or more downlink reference signal configurations; receiving, from the UE, one or more CSI reports of one or more CSI report configurations; The one or more CSI reports include: the one or more downlink reference signals and two codebooks, a spatial codebook including one or more spatial domain (SD) basis components of the precoder; and a delay codebook including one or more delay-domain (DD) basis components of the precoder; and one or more non-zero combining coefficients that complex-combine the one or more SD and DD basis vectors; Each CSI report includes the selected precoding matrix in the form of a precoding matrix identifier (PMI) and a rank identifier (RI), the rank identifier (RI) indicating a transmission rank of an RI layer of the precoding matrix, each CSI report includes two parts, a CSI part 1 and a CSI part 2, CSI part 1 having a fixed payload size and including information indicating a size of the payload of CSI part 2, CSI part 2 including at least amplitude and phase information of the selected non-zero combining coefficients of the CSI report, a bitmap of each layer is segmented into D bit sequences with respect to DD basis indices of the selected DD basis vectors, each bit sequence including 2U×1 bits associated with 2U spatial beams, U indicating the number of SD basis vectors selected from the spatial codebook, each DD basis index being associated with a delay vector from the delay codebook, and the D bit sequences are N ３ The N DD base indexes are ordered with respect to one of two ordering schemes, where ３ denotes the number of DD basis indices of the delay codebook, and N ３ The DD basis indices are ordered as 0, 1, N according to the first ordering scheme. ３ -1, 2, N ３ -2, 3, N ３ -3, 4, N ３ -4, 5, ..., or ３ The DD basis indices are ordered from 0 to N according to the second ordering scheme. ３ −1, 1, N ３ -2, 2, N ３ -3,3,N ３ −4, 4, N ３ -5, 5, ..., the ordering of the amplitude and phase information of the combining coefficients following the order of the bit sequences of the bitmaps of all RI layers, and part or all of CSI part 2 is available for omission from the CSI report.

14. A user equipment (UE) comprising a processor (31) and a memory (32), the memory (32) comprising computer program code (38) executable by the processor, whereby the UE (30) is operable to perform a method according to any one of claims 1 to 12.

15. 14. A network node comprising a processor and a memory, the memory comprising computer program code executable by the processor, whereby the network node is operable to perform the method of claim 13.

16. A computer program (37) comprising computer program code (38), which, when executed by a processor (31) of a user equipment (UE), enables the processor (31) to carry out the method according to any one of claims 1 to 12.

17. A computer program comprising computer program code, said computer program code, when executed by a processor of a network node, enabling said processor to carry out the method of claim 13.

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