Enhanced class II CSI reporting

Abstract

Embodiments of the present disclosure relate to a method performed by a wireless device (500) for generating and reporting a CSI report. Embodiments also relate to a method performed by a network node (600) for receiving a CSI report. The method performed by the wireless device (500) comprises: receiving (400) a CSI report configuration from a network node (600); determining (401) a number of precoder coefficients for the RI transport layer of the precoder vector or matrix; determining (402) a bitmap for indicating non-zero merge coefficients and assigning an order to bits of the bitmap; distributing the same sequence to the plurality of merging coefficients; dividing (403) the plurality of merge coefficients into two or more CSI groups having associated priority levels; and generating (404) a CSI report, the CSI report comprising indications of the SD component, the FD component, the TD component and the bitmap, where the CSI report comprises a CSI part 1 and a CSI part 2, where the CSI part 1 has a fixed payload size and comprises information indicating a payload size of the CSI part 2, and where the CSI part 2 has a fixed payload size and comprises information indicating a payload size of the CSI part 2. And wherein a CSI part 2 comprises the merging coefficient of at least one of two or more of the CSI groups; and transmitting (405), or reporting, to the network node (600) over an uplink (UL) channel, uplink control information (UCI) comprising the CSI report.

Description

Technical Field

[0001] The present disclosure relates to the field of wireless communications, and more particularly to methods and apparatus for codebook-based precoded channel state information (CSI) feedback reporting and uplink control channel (UCI) or CSI omission in wireless communication networks such as advanced 5G networks. Background Art

[0002] Fifth-generation (5G) mobile communication systems, also known as New Radio (NR), offer higher levels of performance than previous generations of mobile communication systems. The driving force behind 5G mobile communications is to provide ubiquitous connectivity for data applications such as automotive communications, remote control with feedback, video downloads, and Internet of Things (IoT) devices and Machine Type Communication (MTC) devices. 5G wireless technology offers several key advantages, such as faster speeds, reduced latency, and increased connectivity. The Third Generation Partnership Project (3GPP) has provided complete system specifications for the 5G network architecture, which includes at least the Radio Access Network (RAN), the Core Transport Network (CN), and service capabilities.

[0003] Figure 1 A simplified schematic diagram illustrates an example of a wireless communication network 100, including a core network (CN) 110 and a radio access network (RAN) 120. As shown, RAN 120 comprises multiple network nodes or radio base stations, referred to as gNBs in 5G. The diagram depicts three radio base stations: gNB1, gNB2, and gNB3. Each gNB serves an area known as a coverage area or cell. Figure 1 Three cells are illustrated: cell 121, cell 122, and cell 123, each served by its own gNB (i.e., gNB1, gNB2, and gNB3). It should be noted that network 100 may include any number of cells and gNBs. A wireless base station, or network node, provides services to users within a cell. In 4G or Long Term Evolution (LTE), a wireless base station is called an eNB; in 3G or Universal Mobile Telecommunications System (UMTS), it is called an eNodeB; and in other radio access technologies, it is called a base station (BS). A user or user equipment (UE) can be a wireless or mobile terminal device or a fixed communication device. A mobile terminal device or UE can also be an IoT device, a Mobile Telecommunications (MTC) device, or other device. IoT devices may include wireless sensors, software, actuators, and computing equipment. They can be embedded in mobile devices, vehicles, industrial equipment, environmental sensors, medical equipment, aircraft, and other devices, as well as network connections that enable these devices to collect and exchange data over existing network infrastructure.

[0004] Back to Figure 1, each cell is shown to contain UEs and IoT devices. gNB1 in cell 121 serves UE1 121A, UE2 121B, and IoT device 121C. Similarly, gNB2 in cell 122 serves UE3 122A, UE4 122B, and IoT device 122C, and gNB3 in cell 123 serves UE5 123A, UE6 123B, and IoT device 123C. Network 100 may contain any number of UEs, IoT devices, or any other type of device. These devices communicate with the serving gNB in ​​the uplink, and the gNB communicates with these devices in the downlink. The individual base stations gNB1 to gNB3 may be connected to CN 120, for example, via an S1 interface, via respective backhaul links 111, 121D, 122D, 123D, which are connected to CN 120 via the S1 interface. Figure 1 The core network 120 is schematically depicted in the figure by arrows pointing to the "core." The core network 120 can connect to one or more external networks, such as the Internet. gNBs can be interconnected via the 5G S1, X2, or XN interfaces, via respective interface links 121E, 122E, and 123E, as depicted by arrows pointing to the gNBs.

[0005] In terms of data transmission, a physical resource grid can be used. The physical resource grid can contain a set of resource elements (REs) to which various physical channels and physical signals are mapped. For example, physical channels may include physical downlink, uplink and / or sidelink (SL) shared channels (PDSCH, PUSCH, PSSCH) (also known as downlink, uplink or sidelink payload data) that carry user-specific data, physical channels may include physical broadcast channels (PBCH) that carry, for example, master information blocks (MIBs) and system information blocks (SIBs), and physical channels may include physical downlink, uplink and / or sidelink control channels (PDCCH, PUCCH, PSCCH) that carry, for example, downlink control information (DCI), uplink control information (UCI) or sidelink control information (SCI). For the uplink, physical channels may also include a physical random access channel (PRACH or RACH) used by the UE to access the network once the UE is synchronized and acquires the MIB and SIBs. Physical signals may include reference signals (RS), synchronization signals (SS), etc. A resource grid may include frames or radio frames with a specific duration in the time domain (e.g. 10 milliseconds) and a given bandwidth in the frequency domain. A radio frame may have a certain number of subframes of predefined length, for example, two subframes of 1 millisecond in length. Each subframe may contain two time slots with multiple OFDM symbols, depending on the length of the cyclic prefix (CP). In 5G, each time slot consists of 14 OFDM symbols or 12 OFDM symbols based on normal CP and extended CP, respectively. A frame may also consist of a smaller number of OFDM symbols when a shortened transmission time interval (TTI) or a microslot / non-slot frame structure including only a few OFDM symbols is adopted. 5G NR supports time slot aggregation, so data transmission can be scheduled to span one or more time slots. The slot format indication informs the UE whether an OFDM symbol is downlink, uplink or flexible.

[0006] The wireless communication network system can be a single-tone or multi-carrier system using frequency division multiplexing, such as an orthogonal frequency division multiplexing (OFDM) system, an orthogonal frequency division multiple access (OFDMA) system, or any other IFFT-based signal with or without CP, such as DFT-OFDM. Other waveforms can also be used, such as non-orthogonal waveforms for multiple access, such as filter bank multi-carrier (FBMC), generalized frequency division multiplexing (GFDM), or universal filtered multi-carrier (UFMC). The wireless communication system can operate, for example, in accordance with the LTE-Advanced pro standard or the 5G or NR (New Radio) standard.

[0007] Figure 1The depicted wireless communication network system may be a heterogeneous network having two different overlapping networks, one being a macro cell network, each macro cell including a macro base station, such as base stations gNB1 to gNB3, and the other being a small cell base station network ( Figure 1 In addition to the wireless networks described above, there are also non-terrestrial wireless communication networks, including spaceborne transceivers (such as satellites) and / or airborne transceivers (such as drone systems). Non-terrestrial wireless communication networks or systems can be similar to those described above. Figure 1 The described terrestrial systems operate in a similar manner, for example according to the LTE-Advanced pro standard or the 5G or NR standard.

[0008] In such Figure 1 In the schematically depicted wireless communication network system, multi-antenna technology (e.g., as used in LTE, NR, or other communication systems) can be used to improve user data rates, link reliability, cell coverage, and network capacity. To support multi-stream or multi-layer transmission, the physical layer of the communication system uses linear precoding. Linear precoding is implemented using a precoder matrix that maps data layers to antenna ports. Precoding can be considered an extension of beamforming, a technique for spatially directing or focusing data toward an intended receiver. The precoding matrix used at the gNB to map data to transmit antenna ports is determined based on channel state information (CSI).

[0009] In wireless communication network systems such as LTE or New Radio (5G), downlink signals carry data signals, control signals including downlink (DL) control information (DCI), and multiple reference signals or symbols (RS) for different purposes. The gNodeB (or gNB or base station) transmits data and downlink control information (DCI) via the so-called physical downlink shared channel (PDSCH) and physical downlink control channel (PDCCH) or enhanced PDCCH (ePDCCH), respectively. Furthermore, the gNB's downlink signals may include one or more types of reference signals (RS), including the common RS (CRS) in LTE, channel state information RS (CSI-RS), demodulation RS (DM-RS), and phase tracking RS (PT-RS). CRS are transmitted across the DL system bandwidth and are used by user equipment (UE) to obtain channel estimates for demodulating data or control information. Compared to CRS, CSI-RS are transmitted at a lower density in the time and frequency domains and are used by the UE for channel estimation or obtaining channel state information (CSI). DM-RS is transmitted only on the bandwidth portion of its respective PDSCH, which the UE uses for data demodulation. For signal precoding at the gNB, several CSI-RS reporting mechanisms are used, such as non-precoded CSI-RS and beamformed CSI-RS reporting. For non-precoded CSI-RS, a one-to-one mapping is used between the CSI-RS ports of the antenna array at the gNB and the transceiver unit (TXRU). Therefore, non-precoded CSI-RS provides cell-wide coverage, where different CSI-RS ports have the same beam direction and beamwidth. For beamformed / precoded UE-specific or non-UE-specific CSI-RS, beamforming is applied on a single antenna port or multiple antenna ports to generate several narrow beams with high gain in different directions, thus not providing cell-wide coverage.

[0010] In wireless communication networks using time division duplex (TDD), CSI is available at the gNB due to channel reciprocity. However, in frequency division duplex (FDD), channel reciprocity is lacking, so channel estimation is performed at the UE and the results are fed back to the gNB. Figure 2 A block-based model for Multiple-Input Multiple-Output (MIMO) DL transmission using codebook-based precoding according to LTE Release-8 is shown. Figure 2Schematically illustrated are a base station 200 (gNB), a user equipment (UE) 202, and a channel 204, such as a radio channel for wireless data communication between the base station 200 and the user equipment 202. The base station includes an antenna array ANTT having multiple antennas or antenna elements, and a precoder 206 that receives a data vector 208 and a precoder matrix F from a codebook 210. Channel 204 can be described by a channel tensor / matrix 212. The user equipment 202 receives the data vector 214 via an antenna or antenna array ANTR having multiple antennas or antenna elements. A feedback channel 216 is provided between the user equipment 202 and the base station 200 for transmitting feedback information. 3GPP releases up to Release 15 support the use of multiple downlink reference symbols (such as CSI-RS) for CSI estimation at the UE.

[0011] In FDD systems (up to Release 15), the channel estimated at the UE is implicitly reported to the gNB, where the CSI report transmitted by the UE over the feedback channel includes the rank index (RI), precoding matrix index (PMI) and channel quality indicator (CQI) (and CRI starting from Release 13), so that the precoding matrix, as well as the modulation order and coding scheme (MCS) of the symbols to be transmitted, can be determined at the gNB. The PMI and RI are used to determine the precoding matrix from a set of predefined matrices Ω (also called a codebook). For example, according to LTE, the codebook can be a lookup table with each entry having a matrix, and the UE's PMI and RI determine which row and column of the table to get the precoder matrix to use. Up to Release 15, the precoder and codebook are designed for a UE equipped with N1 dual-polarized antennas (for a total of N t = 2N1 antennas) or a one-dimensional uniform linear array (ULA) at N1N2 locations (a total of N t=2N1N2 antennas) with a two-dimensional uniform planar array (UPA) of dual-polarized antennas. ULA allows steering of radio waves only in the horizontal (azimuth) direction, enabling azimuth-only beamforming at the gNB, while UPA supports transmit beamforming in both the vertical (elevation) and horizontal (azimuth) directions, also known as full-dimensional (FD) MIMO. For example, in the case of massive antenna arrays (such as FD-MIMO), a codebook can be a set of beamforming weights that form spatially separated electromagnetic transmit / receive beams using the array response vectors of the array. The array's beamforming weights (also called array steering vectors) are the amplitude gain and phase adjustments applied to the signal fed to (or received from) the antenna to transmit (or receive) radiation in a specific direction. The components of the precoder matrix are obtained from the codebook, and the PMI and RI are used to read the codebook and obtain the precoder. When using ULA or UPA for signal transmission, the array steering vectors can be described by the columns of a two-dimensional discrete Fourier transform (DFT) matrix.

[0012] The precoder matrix used in the Type I, Type I multi-panel, and Type II CSI reporting schemes in 3GPP New Radio Release 15 is defined in the frequency domain and has a two-level structure (i.e., two component codebooks): F(s) = F1F2(s), s = 0…, S-1, where S represents the number of subbands. The first component, or so-called first-level precoder F1, is used to select multiple beam vectors from a matrix based on the Discrete Fourier Transform (DFT), also known as the spatial codebook. Furthermore, the first-level precoder F1 corresponds to a wideband matrix that is independent of the subband index s and contains L spatial beamforming vectors (i.e., the so-called spatial beams). These vectors are selected from the DFT-based codebook matrices for the two polarizations of the antenna array,

[0013]

[0014] For the first type of codebook, L = 1, so F1 is simply given by:

[0015]

[0016] The spatial codebook consists of an oversampled DFT matrix of dimension N1N2×N1O1N2O2, where O1 and O2 represent the oversampling factors relative to 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) subsets, each of which contains N1N2 DFT-based vectors, and the parameters q1 and q2 represent the rotation oversampling factors relative to the first and second dimensions of the antenna array, respectively.

[0017] The second component, or so-called second-stage precoder F2(s), is used to combine the selected beam vectors. This means that the second-stage precoder F2(s) corresponds to a selection / combining / co-phasing matrix that is used to select / combine / co-phase the beams defined in F1 for the s-th configured subband. For example, for rank 1 transmission and type I CSI reporting, for a dual-polarized antenna array, F2(s) is given by:

[0018]

[0019] is the quantized in-phase factor (phase adjustment) between the two orthogonal polarizations of the antenna array.Thus, for codebook type I, a single DFT beam is selected in each transmission layer of the precoding such that the transmission is directed towards the strongest path component of the radio channel.

[0020] For rank-1 transmission and Type II CSI reporting, for a dual-polarized antenna array, F2(s) is given by:

[0021]

[0022] where p l and are the quantized amplitude and phase beam combining coefficients, respectively. For a rank R transmission, F2(s) contains R vectors, where R represents the transmission rank, and the entries of each vector are selected to combine single or multiple beams within each polarization.

[0023] The selection of matrices F1 and F2(s) is performed by the UE based on knowledge of reference signals (such as CSI-RS) and channel conditions. The selected matrices are indicated in the CSI report in the form of RI (where RI represents the rank of the precoding matrix) and PMI, and are used at the gNB to update the multi-user precoder for the next transmission time interval.

[0024] In addition to the Class I codebook, the Release 15 3GPP specification also defines a Class I multi-panel (multi-antenna array) codebook for the case where the gNB is equipped with multiple (co-located) antenna panels or antenna arrays (which may not be calibrated). The precoder of this codebook is similar to the Class I codebook, applying a single DFT beam in each transmission layer of the precoding matrix. To account for different spacings between antenna panels and / or possible phase alignment errors between antenna panels (e.g., due to different local oscillators), a panel-specific co-phasing factor is applied to each panel. For example, for a rank 1 transmission and an N g = For a gNB with 2 antenna panels, the Type I multi-panel CSI report is defined as:

[0025]

[0026] in and is the quantized in-phase factor, is the panel-specific in-phase factor applied to the second panel.

[0027] For the two-level Class II CSI report of 3GPP Release 15, the second-level precoder F2(s) is calculated on a subband basis so that for the rth transmission layer, The number of columns depends on the number of configured CQI subbands S. Here, a subband refers to a group of adjacent physical resource blocks (PRBs). One disadvantage of Class II CSI feedback is the large feedback overhead when reporting the combining coefficients based on subbands. The feedback overhead increases approximately linearly with the number of subbands, and when the number of subbands is large, the feedback overhead can become quite large. In order to overcome the high feedback overhead problem of the Class II CSI reporting scheme of Release 15, 3GPP RAN#81 decided to study feedback compression schemes for the second-level precoder F2. In some research results, it was shown that when F2 is transformed into a transform domain called the delay domain using a small number of DFT-based basis vectors, the number of beam combining coefficients in F2 can be significantly reduced. The corresponding three-level precoder relies on three levels (i.e., three components) Codebook. The first component is represented by the matrix F1, which is the same as the NR component of Release 15, is independent of the transmission layer (r), and contains multiple spatial domain (SD) basis vectors selected from the spatial codebook. The second component is represented by the matrix It is layer-dependent and is used to select multiple delay domain (DD) basis vectors from a discrete Fourier transform (DFT)-based matrix (also called a delay codebook). The third component is represented by the matrix It represents a plurality of combining coefficients for combining the SD basis vectors and DD basis vectors selected from the spatial codebook and the delay codebook, respectively.

[0028] Assuming a rank R transmission, for 2N1N2 configured antennas / CSI-RS ports and S configured subbands, for the first polarization of the antenna port and the rth transmission layer, the three-component precoder matrix or CSI matrix is ​​expressed as:

[0029]

[0030] For the second polarization of the antenna port and the rth transmission layer, the three-component precoder matrix or CSI matrix is ​​expressed as:

[0031]

[0032] where b u (l=0,…,L-1) represents the u-th SD basis vector selected from the spatial codebook, is the d-th DD basis vector associated with the r-th layer and selected from the delayed codebook, is the complex delay domain combining coefficient associated with the u-th SD basis vector, the d-th DD basis vector, and the p-th polarization, D represents the number of configured DD basis vectors, and α (r) is a normalized scalar.

[0033] The advantage of the three-component CSI reporting scheme in the above equation is that the feedback overhead of reporting the combining coefficients of the precoder matrix or CSI matrix is ​​no longer related to the number of configured CQI subbands (i.e., independent of the system bandwidth). Therefore, the above three-component codebook has recently been adopted in the two-level Type II CSI reporting specification of 3GPP Release 16.

[0034] Current CSI reporting schemes based on Type II CSI have an inherent drawback: the RI and PMI only contain information about the current channel conditions. Therefore, the CSI reporting rate is related to the channel coherence time, which defines the period of time over which the channel is considered unchanged. This means that in quasi-static channel scenarios, where wireless devices are not moving or are moving slowly, the channel coherence time is long and CSI does not require frequent updates. However, if channel conditions change rapidly, such as due to high speed or rapid movement of wireless devices (or UEs) in a multipath channel environment, the channel coherence time can be very short and the transmitted signal can experience severe fading due to Doppler frequency domain spread. For such channel conditions, CSI needs to be updated frequently, which results in high feedback overhead. In particular, for NR systems (Release 16), which may be more focused on multi-user centricity, multiple CSI reports from users (or UEs) in highly dynamic channel scenarios will significantly reduce the overall efficiency of the communication system.

[0035] UCI Omission for CSI Reporting

[0036] 3GPP Release 15 introduced UCI or CSI omission for PUSCH-based resource allocation and CSI reporting. It allows a wireless device or UE to drop parts of one or more CSI reports when the PUSCH resource allocation is insufficient to carry the entire content of the CSI report. UCI omission can occur when the base station does not accurately allocate PUSCH resources when scheduling CSI reports. For example, the base station may allocate resources for a rank 1 (RI=1) CSI report, but the UE determines rank 2 transmission and reports a rank 2 (RI=2) CSI report whose size is larger than the allocated PUSCH resource size. In this case, the UE must drop part of the UCI content. In 3GPP Release 15 and Release 16, omission is achieved by breaking down the UCI payload associated with the CSI report into smaller parts, so-called priority levels, where priority 0 has the highest priority and represents the total number of CSI reports configured to be carried on the PUSCH. Each priority level is associated with a part of the CSI report. The UE drops the lower priority CSI parts so that the payload size of the CSI report fits within the PUSCH resource allocation. The CSI report is broken down into multiple CSI parts. Here, the CSI part (or so-called subband PMI in Release-15) contains the CSI content associated with the even or odd subband of the CSI report. In addition, each subband PMI is associated with a priority level. The motivation behind the Release-15 subband-based CSI decomposition and omission method is that, in the case of omitting the first subband PMI of CSI report n, the base station can use the CSI content of the second subband PMI reported by CSI report n to estimate the CSI of the omitted first subband PMI by using an interpolation scheme. In this way, severe performance degradation can be avoided because adjacent subbands are usually highly correlated.

[0037] Therefore, the known solutions as described above have disadvantages, which are addressed by the present invention according to the present disclosure.Therefore, new enhanced CSI reporting, schemes and rules are needed, such as CSI or UCI omission. Summary of the Invention

[0038] An object of the embodiments of the present invention is to provide a method and apparatus for codebook-based precoding CSI feedback reporting in a wireless communication network (such as an advanced 5G network).

[0039] According to one aspect of some embodiments of the present invention, a method performed by a wireless device (or user equipment) is provided for generating and reporting or transmitting a channel state information (CSI) report in a wireless communication system, wherein the CSI report indicates a plurality of precoder vectors or matrices, the precoder vectors or matrices being represented as a combination of spatial domain components, frequency domain components, and time domain components, and a set of combining coefficients for combining the spatial domain components, the frequency domain components, and the time domain components. The method comprises:

[0040] receiving a CSI reporting configuration from a network node;

[0041] Determining, based on the received CSI report configuration information, a number of precoder coefficients for a rank index (RI) transmission layer of a precoder vector or matrix;

[0042] determining a bitmap for indicating non-zero combining coefficients in the set of combining coefficients, and assigning an order to bits of the bitmap and assigning the same order to the set of combining coefficients;

[0043] dividing the plurality of combining coefficients into two or more CSI groups having associated priority levels;

[0044] Generating a CSI report, the CSI report including the SD component, the FD component, an indication of the TD component, and the bitmap, wherein the CSI report includes a CSI part 1 and a CSI part 2, wherein the CSI part 1 has a fixed payload size and includes information indicating the payload size of the CSI part 2, and wherein the CSI part 2 includes the combining coefficients of at least one of the two or more CSI groups; and transmitting, or reporting, uplink control information (UCI) including the CSI report to the network node via an uplink (UL) channel.

[0045] According to one aspect of some embodiments of the present invention, the method includes determining, by the wireless device, one or more spatial domain SD components, one or more frequency domain FD components, and one or more time domain TD components for the set of linear combination coefficients for the precoding vector or matrix, and the SD, FD and TD components are indicated in the CSI report.

[0046] According to one aspect of some embodiments of the present invention, the method includes determining a plurality of (S) FD-TD, or SD-TD, or SD-FD component pairs, and indicating the S FD-TD, or SD-TD, or SD-FD component pairs in the CSI report.

[0047] According to an aspect of some embodiments of the present invention, the method comprises indicating a value of S in CSI part 1 or CSI part 2 of the CSI report.

[0048] According to one aspect of some embodiments of the present invention, the method includes multiple CSI groups for UCI or CSI omission in the CSI report, and the bitmap includes RI bit fields, where the rth bit field is associated with the rth layer index and contains 2LS bits, and the bit ordering within each bit field is a function of the SD component index (l) and the FD-TD component pair index (s), given by u=2Ls+l or u=Sl+s, where l={0,…,2L-1}, and s={0,…,S-1}.

[0049] According to one aspect of some embodiments of the present invention, the method includes multiple CSI groups for UCI or CSI omission in the CSI report, and the bitmap includes S bit fields, where the sth bit field is associated with the sth FD-TD component pair index and contains 2L·RI bits, and the bit ordering within each bit field is a function of the SD component index (l) and the layer index (r), given by u=2Lr+l, or u=RI·l+r, where l={0,…,2L-1}, and r={0,…,RI-1}.

[0050] According to one aspect of some embodiments of the present invention, the method includes mapping the associated FD component and TD component to the sth FD-TD component pair of each layer by s=Qm+q or s=Mq+m, where q∈{0,…,Q-1} is the TD component index and m∈{0,…,M-1} is the FD component index.

[0051] According to an aspect of some embodiments of the present invention, there is provided a method performed by a network node for receiving a channel state information (CSI) report in a wireless communication system, the CSI report indicating a plurality of precoder vectors or matrices, the precoder vectors or matrices being represented as a combination of spatial domain components, frequency domain components, and time domain components, and a set of linear combination coefficients for combining the spatial domain components, the frequency domain components, and the time domain components, the method comprising:

[0052] Transmitting a CSI reporting configuration to a wireless device; for causing the wireless device to determine the number of precoder coefficients of an RI transmission layer for a precoder vector or matrix; determining a bitmap for indicating non-zero combining coefficients in the set of combining coefficients, assigning an order to bits of the bitmap, and assigning the same order to a plurality of combining coefficients; dividing the plurality of combining coefficients into two or more CSI groups with associated priority levels; and generating and transmitting or reporting uplink control information (UCI) including the CSI report to the network node via an uplink (UL) channel; and

[0053] A CSI report is received from the wireless device, the CSI report including the SD component, the FD component, an indication of the TD component, and the bitmap, wherein the CSI report includes a CSI part 1 and a CSI part 2, wherein the CSI part 1 has a fixed payload size and includes information indicating the payload size of the CSI part 2, and wherein the CSI part 2 includes the combining coefficients of at least one of two or more of the CSI groups.

[0054] According to an aspect of some embodiments of the present invention, there is provided a network node comprising a processor and a memory, wherein the memory contains instructions executable by the processor, whereby the network node is capable of performing the method of claim 8.

[0055] According to one aspect of some embodiments of the present invention, there is provided a wireless device comprising a processor and a memory, wherein the memory contains instructions executable by the processor, whereby the wireless device is capable of performing the method according to any one of claims 1 to 7.

[0056] There is also provided a computer program comprising instructions which, when executed on at least one processor of a wireless device, causes the at least one processor to perform the actions or method steps presented herein.

[0057] There is also provided a computer program comprising instructions which, when executed on at least one processor of a network node, cause the at least one processor to perform the method steps presented herein.

[0058] A carrier containing the computer program is also provided, wherein the carrier is one of a computer-readable storage medium, an electronic signal, an optical signal or a radio signal.

[0059] Advantages achieved by embodiments of the present invention include significantly reducing the feedback overhead of codebook-based CSI reporting and the computational complexity at the wireless device. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings, in which:

[0061] Figure 1 shows a schematic diagram of a wireless communication system;

[0062] Figure 2 shows a block-based model for MIMO DL transmission using codebook-based precoding according to LTE Release 8;

[0063] Figure 3 is a schematic diagram of a wireless communication system for communicating information between a transmitter and a plurality of receivers, in which embodiments of the present invention may be applied;

[0064] Figure 4 A flow chart illustrating a method performed by a wireless device (or UE) according to some embodiments of the present invention;

[0065] Figure 5 A flow chart illustrating a method performed by a network node according to some embodiments of the present invention;

[0066] Figure 6 is a block diagram depicting a wireless device according to some embodiments of the present invention;

[0067] Figure 7 is a block diagram depicting a network node according to some embodiments of the present invention. DETAILED DESCRIPTION

[0068] The exemplary embodiments are described in detail below with reference to the accompanying drawings, through various scenarios to facilitate understanding of the solutions described herein.

[0069] In order to overcome the above-mentioned problems of the prior art, the invention disclosed in the present invention proposes to extend the NR second-class CSI report to allow time-domain-based downlink precoding for time-varying multipath propagation channels. Compared with the CSI reporting scheme of the prior art, it is proposed to extend the CSI reporting scheme by one or more components (for example, one or more Doppler components or one or more time domain components contained in a new basis vector group of the codebook), which enables the wireless device or network node to perform time-domain-based CSI compression, CSI prediction and reporting for downlink signal precoding. In addition, these components of the CSI report (for example, Doppler or time domain components) significantly reduce the CSI overhead over time because the CSI describes the evolution of the channel over time in a compact manner. Based on these findings, a new second-class CSI reporting (Doppler-based or time-domain-based codebook extension) scheme for NR systems is proposed to overcome the above-mentioned shortcomings. For the new Doppler-based or time-domain-based second-category CSI reporting scheme, the UCI or CSI omission procedures of 3GPP Release-15 and Release-16 cannot be reused because, for example, the subband-based PMI in 3GPP Release-15 does not exist and decomposition into multiple subband PMIs is not possible. Therefore, the present invention, according to this embodiment, addresses the aforementioned shortcomings. Specifically, several UCI or CSI methods and procedures are proposed for the new Doppler-based second-category codebook and CSI reporting.

[0070] Precoder structure and CSI reporting

[0071] It should be noted that the term "precoding" and "precoder" have the same meaning. Therefore, in this disclosure, precoding and precoder can be used interchangeably.

[0072] The term "beam" is used to denote the precoding / filtering of signals at the antenna port of a device (UE or gNB) using a specific set of coefficients to achieve spatially selective / directional transmission of outgoing signals or spatially selective / directional reception of incoming signals. The terms precoding, precoder, or filtering can refer to signal processing performed in either the analog or digital domain. The set of coefficients used for spatially directional transmission / reception in a specific direction can vary depending on the direction. The term "Tx beam" denotes spatially selective / directional transmission, and the term "Rx beam" denotes spatially selective / directional reception. The set of coefficients used for precoding / filtering transmission or reception is referred to as a "spatial filter." In this document, the terms "spatial filter" and "beam direction" are used interchangeably, as the spatial filter coefficients determine the spatial direction of transmission / reception.

[0073] Exemplary embodiments of the present invention may be employed in Figure 1 or Figure 2 The depicted wireless communication system or network is implemented, including a transmitter or transceiver (such as a base station) and a communication device (receiver) or user (such as a mobile or fixed terminal or IoT device or UE), as described in the background technology section above of this disclosure.

[0074] refer to Figure 3 , depicting a method for transmitting data between a transmitter 200 (such as a base station or gNB) and a plurality of wireless devices 2021 to 202 n Schematic diagram of a wireless communication system for communicating information between UEs (e.g., served by a network node such as base station 200). The network node 200 and the UE 202 may communicate via a wireless communication link or channel 204 (e.g., a radio link). The network node 200 includes one or more antennas ANT T or an antenna array having multiple antenna elements, and a signal processor 200a. UE 202 includes one or more antennas ANT R or an antenna array having multiple antennas, a signal processor 202a1, 202a n , and transceivers 202b1, 202b n Base station 200 and each UE 202 may operate in accordance with the inventive teachings described herein.

[0075] According to an embodiment of the present invention, a wireless device is configured to generate a CSI report about a radio channel between the wireless device and a network node (e.g., a gNB in ​​a wireless communication system). The radio channel may be a MIMO channel.

[0076] The wireless device may include one or more of the following: a UE, a mobile terminal, a fixed terminal, a cellular IoT-UE, a vehicle-mounted UE, a vehicle group leader (GL) UE, an IoT, a narrowband IoT (NB-IoT) device, a WiFi non-access point station (non-AP STA) (e.g., 802.11ax or 802.11be), a ground vehicle, an aircraft, a drone, a mobile base station, a roadside unit, a building, or any other item or device (e.g., a sensor or actuator) having a network connection for communicating using a wireless communication network, or a macro cell base station, a small cell base station, a central unit of a base station, a distributed unit of a base station, a repeater, a remote radio head, an AMF, an SMF, a core network entity, a mobile edge computing entity, a network slice in the context of NR or 5G core, or any transmission / reception point (TRP) that enables an item or device to communicate using the wireless communication network, wherein the item or device has a network connection for communicating using the wireless communication network. The receiver may be a network node, a gNB, or a base station. Conversely, the transmitter can be considered as a wireless base station or network node or gNB, while the receiver can be a UE.

[0077] In general, some non-limiting exemplary effects achieved according to the embodiments herein include: a wireless device receives a CSI reporting configuration from a network node or gNB via a higher layer (e.g., RRC), the configuration indicating one or more antenna port groups or CSI-RS resources associated with one or more antenna ports or CSI-RS ports used by the wireless device for CSI measurement. An antenna port group may include or indicate multiple antennas or CSI-RS ports and is associated with a specific set of time-domain and frequency-domain resources of a DL channel. In some examples, an antenna port group is a CSI-RS resource that includes or indicates multiple antennas or CSI-RS ports. A wireless device or user equipment may be configured (via the CSI reporting configuration) with multiple antenna port groups (e.g., multiple CSI-RS resources). In the following, such a configuration is referred to as a CSI-RS burst. Note that in some examples, a wireless device may be configured with multiple antenna port groups, where each antenna port group indicates one or more antennas or CSI-RS ports, and all antenna port groups are associated with a single CSI-RS resource or included in multiple CSI-RS resources. In some examples, a wireless device may be configured with N antenna port groups, where N=2 or N>2. The CSI-RS ports of the configured antenna port groups may be the same or different. In some embodiments, the antenna port groups configured for the wireless device are associated with different time domain resources or time domain opportunities of the DL channel. The CSI report configuration may also include parameters N1 and N2, indicating the number of antennas or CSI-RS ports in the first dimension and the second dimension, respectively.

[0078] Precoder Description

[0079] In certain embodiments, the wireless device determines a precoder or precoder vector or matrix for RI transmission layers and indicates the precoder or precoder vector or matrix in a CSI report. Each precoder vector or matrix in a plurality of precoder vectors or matrices is represented as a linear combination of a spatial domain component, a frequency domain component, and a time domain component, and a set of combining / combining coefficients (as described herein) for combining the spatial domain component, the frequency domain component, and the time domain component. The plurality of precoder vectors or matrices may be represented by indicating the spatial domain component, the frequency domain component, and the time domain component and the set of linear combination coefficients in the CSI report.

[0080] The terms "combining coefficient" and "merging coefficient" are used interchangeably in this disclosure.

[0081] The precoder vector or matrix can be defined across multiple subbands N3 and time instant N4. The bandwidth of the DL channel can be divided into multiple subbands, where each precoder vector or matrix is ​​associated with a subband. In some embodiments, the number of precoder subbands is an integer multiple (or a real multiple less than 1) of the number of CQI subbands configured for the wireless device. The number of CQI subbands can be indicated to the wireless device via the CSI report configuration.

[0082] Each precoder vector or matrix may also be associated with a time of the DL channel. In some examples, the number of time points N4 associated with the precoder may be configured by the network node to the wireless device via a higher layer (e.g., RRC), or derived from another parameter, or selected by the wireless device and reported to the network node.

[0083] A precoder vector or matrix is ​​determined by the wireless device based on measurements of a received reference signal (e.g., CSI-RS), where the reference signal is provided by another wireless device or a network node. The reference signal is configured to the wireless device via a CSI report configuration. The wireless device is configured to perform CSI measurements on a group of antenna ports (i.e., on a CSI-RS burst) and determine a precoder vector or matrix for a plurality of future time slots or time points based on the CSI measurements, and indicate the precoder vector or matrix in a CSI report. The number of future time slots or time points may be configured to the wireless device by the network node.

[0084] The wireless device may perform measurements on the CSI-RS ports at multiple time points (e.g., OFDM symbols, or time slots, or radio frames). In some embodiments, the number of time points may correspond to the size (or length) of the basis vectors in the third set of basis vectors (see below). In some embodiments, the number of time points may correspond to the number of antenna port groups or CSI-RS resources configured for the wireless device to determine the precoder vector or matrix. In some embodiments, the number of time slots or time points is indicated to the wireless device (e.g., via higher layers), or is fixed in the NR specification and known to the wireless device, or is selected by the wireless device and indicated in the CSI report. The wireless device generates and transmits a CSI report indicating the precoder vector or matrix to the network node (gNB) or another wireless device via an uplink channel.

[0085] The spatial domain component of the precoder

[0086] In certain embodiments, the wireless device is configured to determine one or more spatial domain components SD of a set of linear combination coefficients of a precoder. Each SD component corresponds to a basis vector. A set of SD components may correspond to a first set of basis vectors. To determine the precoder vector or matrix, the wireless device is configured to select one or more SD components from the first set of basis vectors. A basis vector from the first set of basis vectors is associated with a set of antenna ports or CSI-RS ports of an antenna port group. A set of antenna ports or CSI-RS ports may be associated with first and second polarizations. The first set of antennas or CSI-RS ports may be associated with the first polarization, and the second set of antennas or CSI-RS ports may be associated with the second polarization. The selection of one or more basis vectors (one or more SD components) from the first set of basis vectors may be polarization-common or polarization-specific. In the case of polarization-common selection, the basis vectors selected from the first set of basis vectors are common to both polarizations of the antennas or CSI-RS ports configured for the wireless device. In the case of polarization-specific selection, the wireless device independently selects basis vectors from the first set for both polarizations of the antennas or CSI-RS ports configured for the wireless device. In an exemplary embodiment, the wireless device selects L basis vectors of a precoder vector or matrix from a first set of basis vectors and indicates the selected L basis vectors in a CSI report. In some examples, the selected L basis vectors are polarization-common, so the L basis vectors selected for the first and second groups of antennas or CSI-RS ports are the same. In some examples, the selected L basis vectors are polarization-dependent, so the L basis vectors selected for the first or second groups of antennas or CSI-RS ports may be different. In some examples, the selected L basis vectors are layer-dependent and are different for a subset of transmission layers of the precoder or for each transmission layer. In this case, each layer subset or each layer of the precoder selects a basis vector independently. In some other examples, the selected L basis vectors are layer-independent and are the same for all layers of the precoder.

[0087] In some embodiments, the first group of basis vectors is an orthogonal basis vector group, that is, the basis vector group includes multiple orthogonal basis vectors. For example, the first group of basis vectors is a basis vector group based on DFT or DCT. In some embodiments, the first group of basis vectors is defined by a DFT or IDFT basis vector group, or by an oversampled DFT or IDFT basis vector group. In some embodiments, the first group of basis vectors includes a group of vectors based on discrete cosine transform (DCT). When the first group of basis vectors is defined by a DFT (DFT or IDFT) based basis vector group, the first group of basis vectors is represented by a DFT or IDFT matrix. In some embodiments, the first group of basis vectors is defined by a rotated DFT-based basis vector, where the index of the DFT-based vector is i1=O1i 11 +q1,i 11=0,…,N1-1,i2=O2i 22 +q2,i 22 =0,…,N2-1, where q1=0,…,O1-1q2=0,…,O2-1 are the rotation factors of the rotated DFT-based basis vectors, N1 and N2 represent the antenna ports with respect to the first and second dimensions, respectively, and O1 and O2 represent the oversampling factors with respect to the first and second dimensions, respectively. In this case, the rotated DFT-based basis vectors are selected from an oversampled DFT-based basis vector consisting of O1O2N1N2 DFT-based vectors. The rotation factors may be selected by the wireless device, configured for the wireless device, or reported by the wireless device as part of a CSI report. The oversampling factor may be configured for the wireless device.

[0088] In some embodiments, the first set of basis vectors is an orthogonal basis vector set, that is, the basis vector set includes multiple orthogonal basis vectors, including an identity matrix. CSI-RS or P CSI-RS Each vector of / 2 is associated with a CSI-RS port and contains P CSI-RS -1 or 0 and 1, where P CSI-RS or P CSI-RS / 2 (eg, per antenna port polarization) is the number of antenna ports of one or more antenna port groups.

[0089] Frequency domain components of the precoder

[0090] In certain embodiments, the wireless device is configured to determine one or more frequency-domain FD components of a set of linear combination coefficients of a precoder. Each frequency-domain FD component of the precoder corresponds to a basis vector. A set of FD components corresponds to a second set of basis vectors. To determine the precoder vector or matrix, the wireless device is configured to select one or more FD components (i.e., basis vectors) from the second set of basis vectors. One basis vector in the second set of basis vectors is associated with a plurality of subbands N3 of the DL channel bandwidth. A subband can contain multiple physical resource blocks (PRBs). In certain embodiments, the number of subbands N3 is related to the number of CQI subbands, or to the size of the CQI subbands configured for the wireless device.

[0091] In some embodiments, the second set of basis vectors is defined by a set of orthogonal basis vectors, i.e., the set of basis vectors includes a plurality of orthogonal vectors. For example, the second set of basis vectors is a DFT- or DCT-based basis vector. In some embodiments, the second set of basis vectors is defined by a DFT- or IDFT-based basis vector, or by an oversampled DFT- or IDFT-based basis vector. In some embodiments, the second set of basis vectors includes a set of discrete cosine transform (DCT)-based vectors. When the second set of basis vectors is defined by a DFT- (DFT- or IDFT-)-based basis vector, the second set of basis vectors can be represented by a DFT or IDFT matrix. In some embodiments, the second set of basis vectors is defined by rotated DFT-based basis vectors, where the index of the DFT-based vector is defined by d3=03i3+q3, i3=0,…,N3-1, where q3=0,…,03-1 is the rotation factor of the rotated DFT-based basis vector. In this case, the rotated DFT-based basis vectors are selected from an oversampled DFT-based basis vector set including O3N3 DFT-based vectors. This means that the set of basis vectors corresponding to the frequency domain components is an oversampled DFT- or DCT-based matrix containing O3 orthogonal DFT- or DCT-based matrices. The rotation factors may be selected by the wireless device, configured to the wireless device, or reported by the wireless device as part of the CSI report. In some embodiments, the number of frequency domain subbands defines the length (N3) of the basis vectors of the second set of basis vectors. The number of frequency domain subbands may be indicated to the wireless device, for example, via higher layers, or may be fixed in the NR specification and known to the wireless device, or selected by the wireless device and indicated in the CSI report.

[0092] In some embodiments, a set of FD components is a basis vector group represented by a DFT-based or DCT-based matrix or an oversampled DFT-based or DCT-based matrix, and the basis vector group contains multiple basis vectors representing the FD components, and each basis vector is a DFT-based or DCT-based vector.

[0093] In some embodiments, the basis vector group of the FD components is an oversampled DFT- or DCT-based matrix, which includes 0 3 orthogonal DFT- or DCT-based matrices.

[0094] Time domain component of the precoder

[0095] In certain embodiments, the wireless device is configured to determine one or more time-domain components of a set of linear combination coefficients of a precoder. Each time-domain component of the precoder corresponds to a basis vector. The set of time-domain components corresponds to a third set of basis vectors (vectors) comprising a plurality of basis vectors. To determine the precoder vector or matrix, the wireless device is configured to select one or more time-domain components (i.e., basis vectors) from the third set of basis vectors. In some examples, the length of the basis vectors (i.e., the number of entries in each basis vector) is defined by an integer multiple of the number of antenna port groups configured for the wireless device (as described above). In some examples, the length of the basis vectors (i.e., the number of entries in each basis vector) is configured for the wireless device by a network node.

[0096] The wireless device is configured to perform measurements on reference signals received by the wireless device at N4 time points (ie, on the configured antenna port set). Note that a time point of a DL channel may be associated with an OFDM symbol, or a symbol set, or a time slot, or a radio frame.

[0097] In some embodiments, the third set of basis vectors includes multiple basis vectors. The third set of basis vectors can be defined by DFT or IDFT basis vectors, or by oversampled DFT or IDFT basis vectors. In some embodiments, the third set of basis vectors includes a set of discrete cosine transform (DCT) based vectors. When the third set of basis vectors is defined by DFT (DFT or IDFT) based basis vectors, the third set of basis vectors can be represented by a DFT or IDFT matrix. In some embodiments, the third set of basis vectors is defined by rotated DFT-based basis vectors, where the index of the DFT-based vector is defined by d4=04i4+q4, i4=0,…,N4-1, where q4=0,…,O4-1 is the rotation factor of the rotated DFT-based basis vector. In this case, the rotated DFT-based basis vectors are selected from the oversampled DFT-based basis vectors including O4N4 DFT-based vectors. This means that the basis vector set corresponding to the time domain components is an oversampled DFT- or DCT-based matrix containing O4 orthogonal DFT- or DCT-based matrices. The rotation factors can be selected by the wireless device, configured to the wireless device, or reported by the wireless device as part of the CSI report. In some embodiments, the number of time points defines the length (N4) of the basis vectors of the third set of basis vectors, and each entry of the basis vector is associated with a time point of the precoder vector or matrix. When the third set of basis vectors is defined by an N4×N4 DFT-based (DFT-based or IDFT-based) matrix, the phase of the elements of each basis vector increases (or decreases) relative to the element index. Therefore, each basis vector of the third set of basis vectors is associated with a Doppler frequency in the transform domain. Therefore, the N4 basis vectors of the third set of basis vectors are associated with N4 different Doppler frequencies. The wireless device selects the basis vectors (i.e., Doppler frequencies) for the precoder based on the measured reference signal.

[0098] Selection of basis vectors and indication in CSI reports

[0099] In certain embodiments, the wireless device determines a set of combining coefficients for a precoder for combining the selected SD component, the TD component, and the FD component. The wireless device generates and transmits a CSI report to a network node or other wireless device, the CSI report including an indication of the selected one or more SD components, an indication of the selected one or more TD components, and an indication of the selected one or more FD components, as well as an indication of the combining coefficients of the precoder vector or matrix.

[0100] In some embodiments, a set of SD components corresponding to a first set of basis vectors includes O1O2N1N2 basis vectors, a set of FD components corresponding to a second set of basis vectors includes N3 basis vectors, and a set of TD components corresponding to a third set of basis vectors includes N4 basis vectors. The wireless device selects L basis vectors from the first set of basis vectors out of the O1O2N1N2 basis vectors, where L < O1O2N1M2. The wireless device selects M basis vectors from the second set of basis vectors out of the M3 basis vectors, where M ≤ N3 or M < N3. The wireless device selects Q basis vectors from the third set of basis vectors out of the N4 basis vectors, where Q ≤ N4 or Q < N4.

[0101] In some embodiments, the wireless device selects a plurality of basis vectors (e.g., L basis vectors) from the first set of basis vectors, where the first set of basis vectors corresponds to a set of SD components, and the number of selected basis vectors is less than the number of the first set of basis vectors. The selected basis vectors are indicated in the CSI report. In some examples, the selected basis vectors are indicated by a bitmap or a combined bit indicator (e.g., by an indicator of one bit or a similar indicator).

[0102] In some embodiments, the wireless device selects a plurality of basis vectors (i.e., M basis vectors) from the second set of basis vectors, where the number of selected basis vectors is less than the number of the second set of basis vectors. In some embodiments, the selected M basis vectors (or delays) are indicated in the CSI report. In some examples, the selected basis vectors are indicated by a bitmap or a combined bit indicator (e.g., an or bit indicator).

[0103] In some embodiments, the wireless device selects a plurality of basis vectors (i.e., Q basis vectors) from the third set of basis vectors, where the number of selected basis vectors is less than the number of the third set of basis vectors. In some embodiments, the selected Q basis vectors (or Doppler frequencies) are indicated in the CSI report. In some examples, the selected basis vectors are indicated by a bitmap or a combined bit indicator (e.g., by an or bit indicator).

[0104] In some embodiments, one or more basis vectors selected from the first, second, and third sets of basis vectors of the precoder are indicated by a bitmap in the CSI report, where each bit is associated with the basis vectors selected from the first, second, and third sets of basis vectors and the combining coefficients of the precoder. In some embodiments, only the non-zero combining coefficients of the precoder vector or matrix are included or indicated in the CSI report.

[0105] In certain embodiments, the number of SD components (e.g., a parameter L indicating the size of the subset of SD components to be selected by the wireless device) is configured to the wireless device, for example, from a network node, gNB, or other wireless device.

[0106] In certain embodiments, the number of FD components (e.g., a parameter M indicating the size of the subset of FD components to be selected by the wireless device) is configured to the wireless device, for example, from a network node, gNB, or other wireless device.

[0107] In certain embodiments, the number of TD components (e.g., a parameter Q indicating the size of the subset of SD components to be selected by the wireless device) is configured to the wireless device, for example, from a network node, gNB, or other wireless device.

[0108] Precoder matrix

[0109] In certain embodiments, the precoder vector or matrix for a transmission layer associated with two polarizations of an antenna port is given by:

[0110]

[0111] in:

[0112] -v l represents a basis vector selected from the first set of basis vectors (a set of spatial domain components) and corresponds to the spatial domain component of the precoder;

[0113] -c l,f,n represents the complex coefficients associated with the lth selected spatial domain component, the fth frequency domain component, and the nth time domain component of the precoder vector or matrix;

[0114] or is the first basis vector selected from the second set of basis vectors associated with the frequency domain components of the precoder. The tth (t=0, 1, ..., N3-1) component / entry of the basis vectors / frequency domain components; and

[0115] or is the first basis vector selected from the third set of basis vectors associated with the time domain component of the precoder. The hth (h=0, 1, ..., N4-1) component / entry of basis vectors / time domain components.

[0116] UCI omitted

[0117] Uplink control information (UCI) omission occurs when the uplink resources provided by the base station or network node to the wireless device or user equipment for uplink transmission are insufficient to carry the entire content of one or more CSI reports. The CSI payload of the CSI report can be controlled by the UE through the number of precoder coefficients to be reported. In the case of UCI or CSI omission, the UE can simply reduce the number of precoder coefficients to be reported for one or more CSI reports based on the available uplink resources (e.g., available PUSCH resources). However, the reduction in the number of such precoder combining coefficients will require recalculation of the precoder coefficients and all basis vectors associated with the precoder vectors or matrices of one or more CSI reports, occupying additional UE resources. Such additional UE resources may not be available at the UE. Therefore, the UCI omission scheme should not require recalculation of the precoder vectors or matrices for one or more CSI reports.

[0118] According to an embodiment, uplink resources or uplink control information (UCI) may include one or more reduced-size CSI reports, where the UCI may include UCI or CSI part 1 and UCI or CSI part 2. In some examples, the UCI or CSI part 1 may include an indication of the number of precoder (amplitude and / or phase) combining coefficients of a precoder vector or matrix per layer or across all layers in the one or more CSI reports. In some examples, the UCI or CSI part 1 may include an indication or rank index (RI) for indicating the number of layers of the precoder vector or matrix in the CSI report for one or more CSI reports.

[0119] According to an embodiment, a UE is configured to receive an uplink resource allocation from a base station for uplink transmission of one or more CSI reports. The UE may determine that the resource allocation size is insufficient to carry the entire content of the CSI report. In this case, the UE may perform a CSI or UCI omission procedure to determine one or more reduced-size CSI reports that fit within the uplink resource allocation. The one or more reduced-size CSI reports may be transmitted to a network node (e.g., a base station, gNB) via an uplink channel.

[0120] In one embodiment, the CSI omission process is based on dropping some amplitude and phase coefficients of the precoder or combining coefficients of one or more CSI reports. This means that the UE is configured to omit parts of the content of one or more CSI reports, thereby providing one or more reduced-size CSI reports for transmission to a network node (e.g., base station, gNB) via an uplink channel.

[0121] According to an embodiment, for each CSI report, a set of combining coefficients is divided into two or more CSI groups for UCI or CSI omission, wherein a specific ordering is applied to the combining coefficients and the combining coefficients are segmented or divided into two or more CSI groups. In addition, each CSI report and each CSI group can be associated with a priority level.

[0122] In one embodiment, the CSI or UCI omission process is based on dropping one or more CSI groups according to a priority rule and thus omitting the associated phase and amplitude of the precoder vector or matrix of the associated CSI report. Thus, in the case of CSI or UCI omission, some amplitude and / or phase coefficients of the precoder vector or matrix indicated in the CSI report are omitted.

[0123] According to an embodiment, the UE may drop low-priority CSI groups in the case of UCI or CSI omission until the payload size of the CSI report conforms to the resource allocation of the network node (e.g., base station, gNB). When omitting a CSI group for a particular priority level, the UE may omit all CSI content for that priority level.

[0124] The following embodiments propose a bit ordering scheme in the bitmap and, therefore, determine the ordering of the combining coefficients. It is assumed that the ordering of the combining coefficients in at least two CSI groups follows the bit ordering of the bitmap. The purpose of the ordering of the combining coefficients is to reduce performance degradation in the case of UCI or CSI omission, i.e., when one or more CSI groups are dropped from the CSI report.

[0125] CSI report configuration

[0126] In certain embodiments, the wireless device is configured to select M FD components for a precoding matrix and indicate the selected M FD components in a CSI report.

[0127] In certain embodiments, the wireless device is configured to select Q TD components for a precoding matrix and indicate the selected Q TD components in a CSI report.

[0128] In certain embodiments, the wireless device is configured to select L SD components for the precoding matrix and indicate the selected L SD components in the CSI report. Note that the SD components are the same for both polarizations of the antenna port. Thus, the precoding matrix is ​​associated with 2L SD components, where L SD components are the same for both polarizations.

[0129] In certain embodiments, the wireless device selects 2LMQ combining coefficients, where L is the number of spatial domain (SD) components, M is the number of frequency domain (FD) components, and Q is the number of time domain (TD) components. The number of SD, FD, and TD components is either selected and reported by the wireless device, configured to the UE by higher layers (e.g., via RRC), or fixed in the specification and known to the wireless device.

[0130] To reduce feedback overhead, the wireless device can be configured to determine K or fewer non-zero combining coefficients from the 2LMQ combining coefficients. The wireless device reports the K non-zero combining coefficients to the network node (e.g., gNB) as part of the CSI report. The value of K is configured for the wireless device, fixed in the 3GPP specification and thus known to the wireless device, or selected by the wireless device and reported to the network node.

[0131] In some embodiments, the wireless device determines a bitmap of size 2LMQ to indicate the locations of selected non-zero combining coefficients. The bitmap consists of 1s and 0s. A 1 is associated with a selected non-zero combining coefficient, a 0 is associated with a zero or unselected combining coefficient, and vice versa. In some examples, the bitmap is selected for each layer of the precoding matrix. The bitmap is part of the CSI report.

[0132] In some embodiments, the wireless device is configured to use A bit indicator indicating the position of the selected non-zero coefficients in the CSI report.

[0133] In certain embodiments, the wireless device is configured to determine S FD-TD component pairs that are shared across a subset of SD components or all SD components of a precoding matrix. An FD-TD component pair is defined as a pair comprising one FD component and one TD component. In some examples, the S FD-TD component pairs are selected for sharing across all SD components in each layer, a subset of layers, or all layers of the precoding matrix. The number of combining coefficients (zero and non-zero combining coefficients) is equal to 2LS for each layer of the precoding matrix. It is noted that multiple combining coefficients associated with different SD components can be associated with the same FD-TD component pair.

[0134] Furthermore, the wireless device is configured to determine K or fewer non-zero combining coefficients from the 2LS combining coefficients. The wireless device reports these non-zero combining coefficients to a network node (e.g., gNB) as part of the CSI report. To indicate the non-zero combining coefficients selected from the 2LS combining coefficients, the wireless device reports a bitmap of size 2LS for each layer, subset of layers, or all layers of the precoding matrix in the case of polarization-specific combining coefficient selection. Since the bitmap size is only 2LS instead of 2LMQ, the CSI reporting overhead is significantly reduced.

[0135] In certain embodiments, S is less than MQ, where M is the number of configured FD components of the precoding matrix and Q is the number of configured TD components of the precoding matrix.

[0136] In some embodiments, a parameter S indicating the number of FD-TD component pairs is configured from a network node to a wireless device via a higher layer (e.g., RRC). The value of S can be configured for each layer, a subset of layers, or all layers of the precoding matrix. In some embodiments, the parameter S indicating the number of FD-TD component pairs is derived from one or more other parameters that are either configured to the wireless device or fixed in the 3GPP specification. In one example, S is derived from a parameter M, where M is the number of configured FD components of the precoding matrix. In another example, S=M. In another example, S is derived from a parameter Q, where Q is the number of configured TD components of the precoding matrix. In another example, S is derived from parameters M and Q, where M is the number of FD components and Q is the number of TD components. In some examples, M is configured to the wireless device by the network node, or M and Q are configured to the wireless device by the network node. In some examples, the value of S is reported by the wireless device to the network node as part of a CSI report for each layer, a subset of layers, or all layers of the precoding matrix. In some examples, the value of S is used by the wireless device bit indicator report.

[0137] In certain embodiments, the wireless device is configured to determine S SD-TD component pairs that are shared across a subset of FD components or all FD components of a precoding matrix. An SD-TD component pair is defined as a pair comprising one SD component and one TD component. In some examples, the S SD-TD component pairs are selected for sharing across all SD components in each layer, a subset of layers, or all layers of the precoding matrix. The number of combining coefficients (zero and non-zero combining coefficients) is equal to MS for each layer. Note that multiple combining coefficients associated with different FD components can be associated with the same SD-TD component pair.

[0138] Furthermore, the wireless device is configured to determine K or fewer non-zero combining coefficients from the MS combining coefficients. The wireless device reports these non-zero combining coefficients to a network node (e.g., a gNB) as part of the CSI report. To indicate the non-zero combining coefficients selected from the MS combining coefficients, the wireless device reports a bitmap of size MS for each layer, subset of layers, or all layers of the precoding matrix in the case of polarization-specific combining coefficient selection. Since the bitmap size is only MS instead of 2LMQ, CSI reporting overhead is significantly reduced.

[0139] In some embodiments, the number S of SD-TD component pairs is less than 2LQ, where L is the number of configured SD components of the precoding matrix per polarization and Q is the number of configured TD components of the precoding matrix.

[0140] In some embodiments, the number of SD-TD component pairs S is configured from the network node to the wireless device via higher layers (e.g., RRC). The value of S can be configured for each layer, a subset of layers, or all layers of the precoding matrix. In some embodiments, the number of SD-TD component pairs S is derived from one or more other parameters that are either configured to the wireless device or fixed in the 3GPP specification. In one example, S is derived from a parameter L, where L is the number of configured SD components of the precoding matrix. In another example, S is derived from a parameter Q, where Q is the number of configured TD components of the precoding matrix. In another example, S is derived from parameters L and Q, where L is the number of SD components and Q is the number of TD components. In some examples, L is configured to the wireless device by the network node, or L and Q are configured to the wireless device by the network node. In some examples, the value of S is reported by the wireless device to the network node as part of the CSI report for each layer, a subset of layers, or all layers of the precoding matrix. In some examples, the value of S is used by the wireless device bit indicator report.

[0141] In certain embodiments, the wireless device is configured to determine S SD-FD component pairs that are shared across a subset of TD components or all TD components of a precoding matrix. An SD-FD component pair is defined as a pair comprising one SD component and one FD component. In some examples, the S SD-FD component pairs are selected for sharing across all TD components in each layer, a subset of layers, or all layers of the precoding matrix. The number of combining coefficients (zero and non-zero combining coefficients) is equal to QS for each layer. Note that multiple combining coefficients associated with different TD components can be associated with the same SD-FD component pair.

[0142] Furthermore, the wireless device is configured to determine K or fewer non-zero combining coefficients from the QS combining coefficients. The wireless device reports these non-zero combining coefficients to the network node (e.g., gNB) as part of the CSI report. To indicate the non-zero combining coefficients selected from the QS combining coefficients, the wireless device reports a bitmap of size QS for each layer, subset of layers, or all layers of the precoding matrix in the case of polarization-specific combining coefficient selection. Since the bitmap size is only QS instead of 2LMQ, the CSI reporting overhead is significantly reduced.

[0143] In certain embodiments, the number S of SD-FD component pairs is less than 2LM, where M is the number of configured FD components of the precoding matrix and L is the number of configured SD components of the precoding matrix for each polarization.

[0144] In some embodiments, the number S of SD-FD component pairs is configured from the network node to the wireless device via higher layers (e.g., RRC). The value of S can be configured for each layer, a subset of layers, or all layers of the precoding matrix. In some embodiments, the number S of SD-FD component pairs is derived from one or more other parameters that are either configured to the wireless device or fixed in the 3GPP specification. In one example, S is derived from a parameter L, where L is the number of configured SD components of the precoding matrix. In another example, S is derived from a parameter M, where M is the number of configured FD components of the precoding matrix. In another example, S is derived from parameters L and M, where L is the number of SD components and M is the number of FD components. In some examples, L is configured to the wireless device by the network node, or L and M are configured to the wireless device by the network node. In some examples, the value of S is reported by the wireless device to the network node as part of the CSI report for each layer, a subset of layers, or all layers of the precoding matrix. In some examples, the value of S is used by the wireless device bit indicator report.

[0145] Bit ordering of bitmap in CSI report

[0146] Option 1:

[0147] In certain embodiments, the wireless device generates a bitmap comprising RI bit fields, wherein the r-th bit field comprises 2LS bits. Each bit in the r-th bit field is associated with one SD component of the L SD components and one FD-TD component pair of the S FD-TD component pairs. The RI bit fields are associated with the RI layers of the precoding matrix, and the RI bit fields indexed with r={0,…,RI-1} are sorted in increasing order from left to right. The ordering of the bits in the r-th bit field associated with the r-th layer and the associated combining coefficients of the precoding matrix are explained in more detail below. Note that the ordering of the combining coefficients associated with the r-th layer of the precoding matrix follows the bit ordering of the r-th bit field.

[0148] In the following embodiments, it is always assumed that each bit is associated with a combining coefficient, where "0" indicates that the associated combining coefficient is not reported and "1" indicates that the associated combining coefficient is reported. Therefore, the order of the bits in each bit field is the same as the order of the combining coefficients associated with the bits of the bit field. Note that the definition of the bit field may change as explained in the following embodiments.

[0149] In this embodiment, it is assumed that each merging coefficient of the r-th layer of the precoding matrix is ​​associated with two indices (l, s), where l is the SD index and s is the FD-TD component pair index, and l = 0, .., 2L-1, = 0, .., S-1, and the ordering of the index u (u = 0, ..., 2LS-1) associated with the bits of the r-th bit field and the merging coefficients follows one of the following ordering schemes. An example of mapping from index (l, s) to index u is explained below. In one scheme, the ordering of the index u (u = 0, ..., 2LS-1) associated with the bits of the r-th bit field is a function of the index (l, s) and is given by u = 2Ls + l, where s = {0, ..., S-1} and l = {0, ..., 2L-1}. In another approach, the ordering of the indices u (u=0,…,2LS-1) associated with the bits of the rth bit field is a function of the indices (l,s) and is given by u=Sl+s, where s={0,…,S-1} and l={0,…,2L-1}.

[0150] In the first example, the mapping of the associated FD and TD components to the sth FD-TD component pair at each layer is given by s=Qm+q, where q∈{0,...,Q-1} is the TD component index and m∈{0,...,M-1} is the FD component index. In the second example, the mapping of the associated FD and TD components to the sth FD-TD component pair at each layer is given by s=Mq+m, where q∈{0,...,Q-1} is the TD component index and m∈{0,...,M-1} is the FD component index.

[0151] Option 2:

[0152] In certain embodiments, the wireless device generates a bitmap comprising RI bit fields, wherein the r-th bit field comprises MS bits. The RI bit fields are associated with the RI layer, and the RI bit fields with indices r = {0, ..., RI-1} are sorted in increasing order from left to right. The ordering of the bits associated with the r-th bit field is based on one of the following ordering schemes. Here, it is assumed that each combining coefficient of the r-th layer of the precoding matrix is ​​associated with two indices (m, s), where m = 0, ..., M-1, s = 0, ..., S-1, and the index u (u = 0, ..., MS-1) associated with the bits of the r-th bit field and the ordering of the combining coefficients follow one of the following schemes. An example of a mapping from an index (m, s) to an index u is explained below.

[0153] In one scheme, the bit ordering of the r-th bit field is given by u=Ms+m, where s={0,…,S-1} and m={0,…,M-1}. In another scheme, the bit ordering of the r-th bit field is given by u=Sm+s, where s={0,…,S-1} and m={0,…,M-1}.

[0154] In the first example, the mapping of the associated SD and TD components to the sth SD-TD component pair of each layer is given by s = 2Lq + l, where q ∈ {0, ..., Q-1} is the TD component index and l ∈ {0, ..., 2L-1} is the SD component index. In the second example, the mapping of the associated FD and TD components to the sth SD-TD component pair of each layer is given by s = Ql + q, where q ∈ {0, ..., Q-1} is the TD component index and l ∈ {0, ..., 2L-1} is the SD component index.

[0155] Option 3:

[0156] In certain embodiments, the wireless device generates a bitmap comprising RI bit fields, wherein the r-th bit field comprises QS bits. The RI bit fields are associated with the RI layer, and the RI bit fields with indices r = {0, ..., RI-1} are ordered in increasing order from left to right. The ordering of the bits in the r-th bit field associated with the r-th layer is based on any of the following ordering schemes:

[0157] In this embodiment, it is assumed that each combining coefficient of the r-th layer of the precoding matrix is ​​associated with two indices (q, s), where q = 0, ..., Q-1, s = 0, ..., S-1, and the index u (u = 0, ..., QS-1) associated with the bits of the r-th bit field and the ordering of the combining coefficients follow one of the following schemes. An example of mapping from the index (q, s) to the index u is explained below.

[0158] In one scheme, the bit ordering of the r-th bit field is given by u=Qs+q, where s={0,…,S-1} and q={0,…,Q-1}. In another scheme, the bit ordering of the r-th bit field is given by u=Sq+s, where s={0,…,S-1} and q={0,…,Q-1}.

[0159] In the first example, the mapping of the associated SD and FD components to the sth SD-FD component pair of each layer is given by s = 2Lm + l, where m ∈ {0, ..., M-1} is the FD component index and l ∈ {0, ..., 2L-1} is the SD component index. In the second example, the mapping of the associated SD and FD components to the sth SD-FD component pair of each layer is given by s = Ml + m, where m ∈ {0, ..., M-1} is the FD component index and l ∈ {0, ..., 2L-1} is the SD component index.

[0160] Sorting of bitmaps across RI layers and sorting of merging coefficients

[0161] Option 4:

[0162] In some embodiments, the wireless device generates a bitmap comprising S bit fields, where the sth bit field comprises 2L·RI bits, where RI is the rank of the precoding matrix. The S bit fields are associated with the S FD-TD component pairs at the RI level of the precoding matrix in increasing or decreasing order. In some embodiments, the S bit fields, indexed s = {0, ..., S-1}, are ordered in increasing order from left to right.

[0163] The ordering of bits in the sth bit field associated with the sth component pair on the RI layer is based on one of the following ordering schemes.

[0164] In this embodiment, it is assumed that each combining coefficient associated with the sth component pair of the precoding matrix (across the RI layer) is associated with two indices (r, l), where r = 0, .. , RI-1, l = 0, .. , 2L-1, and the index u (u = 0, ..., 2LRI-1) associated with the bit of the sth bit field and the index ordering of the combining coefficients follow one of the following schemes. An example of mapping from the index (r, l) to the index u is explained below.

[0165] In one approach, the bit ordering of the sth bit field associated with the sth component pair across the RI layer is given by u=2Lr+l, where r={0,...,RI-1} and l={0,...,2L-1}. In another approach, the bit ordering of the sth bit field associated with the sth component pair across the RI layer is given by u=RI·l+r, where r={0,...,RI-1} and l={0,...,2L-1}.

[0166] In the first example, the mapping of the associated FD and TD components to the sth FD-TD component pair at each layer is given by s=Qm+q, where q∈{0,...,Q-1} is the TD component index and m∈{0,...,M-1} is the FD component index. In the second example, the mapping of the associated FD and TD components to the sth FD-TD component pair at each layer is given by s=Mq+m, where q∈{0,...,Q-1} is the TD component index and m∈{0,...,m-1} is the FD component index.

[0167] Option 5:

[0168] In some embodiments, the wireless device generates a bitmap comprising S bit fields, where the sth bit field comprises M·RI bits. The S bit fields are associated with the S SD-TD component pairs on the RI layer of the precoding matrix in ascending or descending order. In some embodiments, the S bit fields indexed s={0, ..., S-1} are ordered in ascending order from left to right.

[0169] The ordering of bits in the sth bit-field associated with the sth component pair is based on any of the following ordering schemes.

[0170] In this embodiment, it is assumed that each combining coefficient associated with the sth component pair of the precoding matrix (across the RI layer) is associated with two indices (m, r), where m = 0, ..., M-1, r = 0, ..., RI-1, and the index u (u = 0, ..., M·RI-1) associated with the bits of the sth bit field and the index ordering of the combining coefficients follow one of the following schemes. An example of mapping from the index (m, r) to the index u is explained below.

[0171] In one approach, the bit ordering of the s-th bit field associated with the s-th component pair (across the RI layer) is given by u=M·r+m, where r={0,…,RI-1} and m={0,…,M-1}. In another approach, the bit ordering of the s-th bit field associated with the s-th component pair (across the RI layer) is given by u=RI·m+r, where r={0,…,RI-1} and m={0,…,M-1}.

[0172] In the first example, the mapping of the associated SD and TD components to the sth SD-TD component pair of each layer is given by s = 2Lq + l, where q ∈ {0, ..., Q-1} is the TD component index and l ∈ {0, ..., 2L-1} is the SD component index. In the second example, the mapping of the associated FD and TD components to the sth SD-TD component pair of each layer is given by s = Ql + q, where q ∈ {0, ..., Q-1} is the TD component index and l ∈ {0, ..., 2L-1} is the SD component index.

[0173] Option 6:

[0174] In some embodiments, the wireless device generates a bitmap comprising S bit fields, where the sth bit field comprises Q·RI bits. The S bit fields are associated with the S SD-FD component pairs on the RI layer of the precoding matrix in ascending or descending order. In some embodiments, the S bit fields indexed s={0, ..., S-1} are ordered in ascending order from left to right.

[0175] The ordering of bits in the sth bit-field associated with the sth component pair is based on any of the following ordering schemes.

[0176] In this embodiment, it is assumed that each combining coefficient associated with the sth component pair of the precoding matrix (across the RI layer) is associated with two indices (q, r), where q = 0, ..., Q-1, r = 0, ..., RI-1, and the index u (u = 0, ..., Q RI-1) associated with the bits of the sth bit field and the index ordering of the combining coefficients follow one of the following schemes. An example of mapping from the index (q, r) to the index u is explained below.

[0177] In one approach, the bit ordering of the s-th bit field associated with the s-th component pair (across the RI layer) is given by u=Qr+q, where r={0,...,RI-1} and mq={0,...,Q-1}. In another approach, the bit ordering of the s-th bit field associated with the s-th component pair (across the RI layer) is given by u=RI·q+r, where r={0,...,RI-1} and q={0,...,Q-1}.

[0178] In the first example, the mapping of the associated SD components and FD components to the sth SD-FD component pair of each layer is given by s=2Lm+l, where m∈{0,...,M-1} is the FD component index and l∈{0,...,2L-1} is the SD component index. In the second example, the mapping of the associated SD components and FD components to the sth SD-FD component pair of each layer is given by s=Ml+m, where qm∈{0,...,M-1} is the FD component index and l∈{0,...,2L-1} is the SD component index.

[0179] Option 7:

[0180] In certain embodiments, the wireless device generates a bitmap comprising S bit fields, where S ≤ MQ, and the s-th bit field comprises 2L·RI bits. The S bit fields are associated with S FD-TD components, and the S bit fields, indexed s = {0, ..., S-1}, are ordered in increasing order from left to right. The mapping of the associated FD and TD components to the s-th FD-TD component pair of each layer is given by s = Mq + m, where q ∈ {0, ..., Q-1} is the TD component index and m ∈ {0, ..., M-1} is the FD component index. The S FD-TD component pairs associated with the S bit fields are grouped into Q groups, where the q-th group contains M FD-TD component pairs associated with the same TD component. Furthermore, the S bit fields are grouped into Q bit fields, where the q-th bit field comprises 2LM·RI bits. In one example, the Q groups are ordered with respect to increasing TD component indices. In another example, the Q groups are ordered with respect to a permutation function of the Q TD component indices. The ordering of bits in each qth group is given by the following ordering scheme.

[0181] In this embodiment, it is assumed that each bit of the qth group or bit field is associated with three indices (l, r, m), where l = 0, .., 2l-1, r = 0, .., RI-1, and m = 0, .., M-1, and the index u (u = 0, ..., 2L·M·RI-1) associated with the bits of the qth bit field and the index ordering of the combining coefficients follow one of the following schemes. An example of mapping from the index (l, r, m) to the index u is explained below.

[0182] In the first scheme, the bit ordering in each qth group is given by u = 2LMr + Ml + m, where r = {0, ..., RI}, m = {0, ..., m-1}, and l = {0, ..., 2L-1}. In the second scheme, the bit ordering in each qth group is given by u = 2LMr + 2Lm + l, where r = {0, ..., RI}, m = {0, ..., M-1}, and l = {0, ..., 2L-1}. In the third scheme, the bit ordering in each qth group is given by u = 2L·RI·m+RI·l+r, where r = {0, ..., RI}, m = {0, ..., <-1}, and l = {0, ..., 2L-1}. In the fourth scheme, the bit ordering in each qth group is given by u = 2L·RI·m+2Lr+l, where r = {0,…,RI}, m = {0,…,M-1}, and l = {0,…,2L-1}. In the fifth scheme, the bit ordering in each qth group is given by u = M·RI·l+Mr+m, where r = {0,…,RI}, m = {0,…,M-1}, and l = {0,…,2L-1}. In the sixth scheme, the bit ordering in each qth group is given by u = M·RI·l+RI·m+r, where r = {0,…,RI}, m = {0,…,M-1}, and l = {0,…,2L-1}.

[0183] Option 8:

[0184] In certain embodiments, the wireless device generates a bitmap comprising S bit fields, where S ≤ 2LQ, and the s-th bit field comprises M·RI bits. The S bit fields are associated with the S SD-TD components, and the S bit fields indexed s = {0, ..., S-1} are ordered in increasing order from left to right. The mapping of the associated SD component and TD component to the s-th SD-TD component pair of each layer is given by s = 2Lq + l, where q∈{0, ..., Q-1} is the TD component index and l∈{0, ..., 2L-1} is the SD component index. The S SD-TD component pairs associated with the S bit fields are grouped into Q groups, where the q-th group comprises 2L SD-TD component pairs associated with the same TD component. Furthermore, the S bit fields are grouped into Q bit fields, where the q-th bit field comprises 2LM·RI bits. In one example, the Q groups are ordered with respect to increasing TD component indices. In another example, the Q groups are ordered with respect to a permutation function of the Q TD component indices.The ordering of bits in each qth group is given by the following ordering scheme.

[0185] In this embodiment, it is assumed that each bit of the qth group is associated with three indices (m, r, l), where l = 0, .., 2L-1, r = 0, .., RI-1, and m = 0, .., M-1, and the index u (u = 0, ..., 2L·M·RI-1) associated with the bit of the mth bit field and the index ordering of the combining coefficients follow one of the following schemes. An example of mapping from the index (m, r, l) to the index u is explained below.

[0186] In the first scheme, the bit ordering in each qth group is given by u = 2LMr + Ml + m, where r = {0, ..., RI}, m = {0, ..., M-1}, and l = {0, ..., 2L-1}. In the second scheme, the bit ordering in each qth group is given by u = 2LMr + 2Lm + l, where r = {0, ..., RI}, m = {0, ..., M-1}, and l = {0, ..., 2L-1}. In the third scheme, the bit ordering in each qth group is given by u = 2L·RI·m+Rl+r, where r = {0, ..., RI}, m = {0, ..., M-1}, and l = {0, ..., 2L-1}. In the fourth scheme, the bit ordering in each qth group is given by u = 2L·RI·m+2Lr+l, where r = {0,…,RI}, m = {0,…,M-1}, and l = {0,…,2L-1}. In the fifth scheme, the bit ordering in each qth group is given by u = M·RI·l+Mr+m, where r = {0,…,RI}, m = {0,…,M-1}, and l = {0,…,2L-1}. In the sixth scheme, the bit ordering in each qth group is given by u = M·RI·l+RI·m+r, where r = {0,…,RI}, m = {0,…,M-1}, and l = {0,…,2L-1}.

[0187] Option 9:

[0188] In certain embodiments, the wireless device generates a bitmap comprising S bit fields, where S ≤ MQ, and the s-th bit field comprises 2L·RI bits. The S bit fields are associated with S FD-TD components, and the S bit fields, indexed s = {0, ..., S-1}, are ordered in increasing order from left to right. The mapping of the associated FD and TD components to the s-th FD-TD component pair of each layer is given by s = Qm + q, where q ∈ {0, ..., Q-1} is the TD component index and m ∈ {0, ..., M-1} is the FD component index. The S FD-TD component pairs associated with the S bit fields are grouped into M groups, where the m-th group contains Q FD-TD component pairs associated with the same FD component. Furthermore, the S bit fields are grouped into M bit fields, where the m-th bit field comprises 2LQ·RI bits. In one example, the M groups are ordered with respect to increasing FD component indices. In another example, the M groups are ordered with respect to a permutation function of the M FD component indices. The ordering of bits in each m-th group is given by the following ordering scheme.

[0189] In this embodiment, it is assumed that each bit of the m-th group is associated with three indices (l, r, q), where l = 0, .., 2L-1, r = 0, .., RI-1, q = 0, ..., Q-1, and the index u (u = 0, ..., 2L·Q·RI-1) associated with the bits of the m-th bit field and the index ordering of the combining coefficients follow one of the following schemes. An example of mapping from the index (l, r, q) to the index u is explained below.

[0190] In the first scheme, the bit ordering in each m-th group is given by u = 2LQr + Ql + q, where r = {0, ..., RI}, q = {0, ..., Q-1}, and l = {0, ..., 2L-1}. In the second scheme, the bit ordering in each m-th group is given by u = 2LQr + 2Lq + l, where r = {0, ..., RI}, q = {0, ..., Q-1}, and l = {0, ..., 2L-1}. In the third scheme, the bit ordering in each m-th group is given by u = 2L·RI·q + RI·l + r, where r = {0, ..., RI}, q = {0, ..., Q-1}, and l = {0, ..., 2L-1}. In the fourth scheme, the bit ordering in each m-th group is given by u = 2L·RI·+2Lr+l, where r = {0,…,RI}, q = {0,…,Q-1}, and l = {0,…,2L-1}. In the fifth scheme, the bit ordering in each m-th group is given by u = Q·RI·l+Qr+q, where r = {0,…,RI}, q = {0,…,Q-1}, and l = {0,…,2L-1}. In the sixth scheme, the bit ordering in each m-th group is given by u = Q·RI·l+RI·q+r, where r = {0,…,RI}, q = {0,…,Q-1}, and l = {0,…,2L-1}.

[0191] Option 10:

[0192] In certain embodiments, the wireless device generates a bitmap comprising S bit fields, where S ≤ 2LM and the sth bit field comprises Q·RI bits. The S bit fields are associated with the S SD-FD components, and the S bit fields indexed s = {0, ..., S-1} are ordered in increasing order from left to right. The mapping of the associated SD component and FD component to the sth SD-FD component pair of each layer is given by s = 2Lm + l, where m∈{0, ..., M-1} is the FD component index and l∈{0, ..., 2L-1} is the SD component index. The S SD-FD component pairs associated with the S bit fields are grouped into M groups, where the mth group comprises 2L SD-FD component pairs associated with the same FD component. Furthermore, the S bit fields are grouped into M bit fields, where the mth bit field comprises 2LQ·RI bits. In one example, the M groups are ordered with respect to increasing FD component indices. In another example, the M groups are ordered with respect to a permutation function of the M FD component indices. The bit ordering in each m-th group is given by the following ordering scheme.

[0193] In this embodiment, it is assumed that each bit of the m-th group is associated with three indices (q, r, l), where q = 0, ..., Q-1, r = 0, ..., RI-1, and l = 0, ..., 2l-1, and the index u (u = 0, ..., 2LQ RI-1) associated with the bits of the m-th bit field and the index ordering of the combining coefficients follow one of the following schemes. An example of mapping from the index (q, r, l) to the index u is explained below.

[0194] In the first scheme, the bit ordering in each m-th group is given by u = 2LQr + Ql + q, where r = {0, ..., RI}, q = {0, ..., Q-1}, and l = {0, ..., 2L-1}. In the second scheme, the bit ordering in each m-th group is given by u = 2LQr + 2Lq + l, where r = {0, ..., RI}, q = {0, ..., Q-1}, and l = {0, ..., 2L-1}. In the third scheme, the bit ordering in each m-th group is given by u = 2L·RI·q + Rl + r, where r = {0, ..., RI}, q = {0, ..., Q-1}, and l = {0, ..., 2L-1}. In the fourth scheme, the bit ordering in each m-th group is given by u = 2L·RI·q + 2Lr + l, where r = {0, ..., RI}, q = {0, ..., Q-1}, and l = {0, ..., 2L-1}. In the fifth scheme, the bit ordering in each m-th group is given by u = Q·RIl + Qr + q, where r = {0, ..., RI}, q = {0, ..., Q-1}, and l = {0, ..., 2L-1}. In the sixth scheme, the bit ordering in each m-th group is given by u = Q·RI·l + RI·q + r, where r = {0, ..., RI}, q = {0, ..., Q-1}, and l = {0, ..., 2L-1}.

[0195] Option 11:

[0196] In certain embodiments, the wireless device generates a bitmap comprising S bit fields, where S ≤ 2LQ, and the s-th bit field comprises M·RI bits. The S bit fields are associated with the S SD-TD components, and the S bit fields, indexed s = {0, ..., S-1}, are ordered in increasing order from left to right. The mapping of the associated SD component and TD component to the s-th SD-TD component pair of each layer is given by s = Ql + q, where q∈{0, ..., Q-1} is the TD component index and l∈{0, ..., 2L-1} is the SD component index. The S SD-TD component pairs associated with the S bit fields are grouped into 2L groups, where the l-th group comprises Q SD-TD component pairs associated with the same SD component. Furthermore, the S bit fields are grouped into 2L bit fields, where the l-th bit field comprises MQ·RI bits. In one example, the 2L groups are ordered relative to increasing FD component indices. In another example, the 2L groups are ordered with respect to a permutation function of the 2L SD component indices. The bit ordering in each l-th group is given by the following ordering scheme.

[0197] In this embodiment, it is assumed that each bit of the l-th group is associated with three indices (m, r, q), where q = 0, ..., Q-1, r = 0, ..., RI-1, and m = 0, ..., M-1, and the index u (u = 0, ..., MQ·RI-1) associated with the bits of the l-th bit field and the index ordering of the combining coefficients follow one of the following schemes. An example of mapping from the index (m, r, q) to the index u is explained below.

[0198] In the first scheme, the bit ordering in each l-th group is given by u = MQr + Qm + q, where r = {0, ..., RI}, q = {0, ..., Q-1}, and m = {0, ..., M-1}. In the second scheme, the bit ordering in each l-th group is given by u = MQr + Mq + m, where r = {0, ..., RI}, q = {0, ..., Q-1}, and m = {0, ..., M-1}. In the third scheme, the bit ordering in each l-th group is given by u = M·RI·q + Rm + r, where r = {0, ..., RI}, q = {0, ..., Q-1}, and m = {0, ..., M-1}. In the fourth scheme, the bit ordering in each l-th group is given by u = M·RI·q+Mr+m, where r = {0,…,RI}, q = {0,…,Q-1}, and m = {0,…,M-1}. In the fifth scheme, the bit ordering in each l-th group is given by u = Q·RI·m+Qr+q, where r = {0,…,RI}, q = {0,…,Q-1}, and m = {0,…,M-1}. In the sixth scheme, the bit ordering in each l-th group is given by u = Q·RI·m+RI·q+r, where r = {0,…,RI}, q = {0,…,Q-1}, and m = {0,…,M-1}.

[0199] Option 12:

[0200] In certain embodiments, the wireless device generates a bitmap comprising S bit fields, where S ≤ 2LM, and the s-th bit field comprises Q·RI bits. The S bit fields are associated with the S SD-FD components, and the S bit fields, indexed s = {0, ..., S-1}, are ordered in increasing order from left to right. The mapping of the associated SD component and FD component to the s-th SD-FD component pair of each layer is given by s = Ml + m, where m∈{0, ..., M-1} is the FD component index and l∈{0, ..., 2L-1} is the SD component index. The S SD-FD component pairs associated with the S bit fields are grouped into 2L groups, where the l-th group comprises M SD-FD component pairs associated with the same SD component. Furthermore, the S bit fields are grouped into 2L bit fields, where the l-th bit field comprises MQ·RI bits. In one example, the 2L groups are ordered with respect to increasing SD component indices. In another example, the 2L groups are ordered with respect to a permutation function of the 2L SD component indices. The bit ordering in each l-th group is given by the following ordering scheme.

[0201] In this embodiment, it is assumed that each bit of the l-th group is associated with three indices (q, r, m), where q = 0, ..., Q-1, r = 0, ..., RI-1, and m = 0, ..., M-1, and the index u (u = 0, ..., MQ·RI-1) associated with the bits of the l-th bit field and the index ordering of the combining coefficients follow one of the following schemes. An example of mapping from the index (q, r, m) to the index u is explained below.

[0202] In the first scheme, the bit ordering in each l-th group is given by u = MQr + Qm + q, where r = {0, ..., RI}, q = {0, ..., Q-1}, and m = {0, ..., M-1}. In the second scheme, the bit ordering in each l-th group is given by u = MQr + Mq + m, where r = {0, ..., RI}, q = {0, ..., Q-1}, and m = {0, ..., M-1}. In the third scheme, the bit ordering in each l-th group is given by u = M·RI·q + Rm + r, where r = {0, ..., RI}, q = {0, ..., Q-1}, and m = {0, ..., M-1}. In the fourth scheme, the bit ordering in each l-th group is given by u = M·RI·q+Mr+m, where r = {0,…,RI}, q = {0,…,Q-1}, and m = {0,…,M-1}. In the fifth scheme, the bit ordering in each l-th group is given by u = Q·RI·m+Qr+q, where r = {0,…,RI}, q = {0,…,Q-1}, and m = {0,…,M-1}. In the sixth scheme, the bit ordering in each l-th group is given by u = Q·RI·m+RI·q+r, where r = {0,…,RI}, q = {0,…,Q-1}, and m = {0,…,M-1}.

[0203] Reporting and configuration of the number of non-zero combining coefficients

[0204] In some embodiments, the wireless device is configured to determine K or fewer non-zero combining coefficients from the 2LS combining coefficients, where S ≤ MQ. In some embodiments, the wireless device is configured to determine K or fewer non-zero combining coefficients for all RI layers from the 2LS.RI combining coefficients, where S ≤ MQ.

[0205] In some embodiments, the wireless device is configured to determine K or fewer non-zero combining coefficients from the MS combining coefficients, where S ≤ 2LQ. In some embodiments, the wireless device is configured to determine K or fewer non-zero combining coefficients for all RI layers from the MS.RI combining coefficients, where S ≤ 2LQ.

[0206] In some embodiments, the wireless device is configured to determine K or fewer non-zero combining coefficients from 2LS combining coefficients, where S ≤ 2LM. In some embodiments, the wireless device is configured to determine K or fewer non-zero combining coefficients in all RI layers from 2LS.RI combining coefficients, where S ≤ 2LM.

[0207] In some embodiments, the maximum number K of non-zero combining coefficients is a function of three parameters L, M, and β, where L is the number of configured SD components, M is the number of configured FD components, and β is a parameter configured by the network for controlling the number of non-zero coefficients.

[0208] In some embodiments, the maximum number K of non-zero combining coefficients is a function of three parameters L, M, and Q, where L is the number of configured SD components, M is the number of configured FD components, and Q is the number of configured TD components.

[0209] In some embodiments, the maximum number of non-zero combining coefficients does not exceed 2LS per layer, where S < MQ, L is the number of configured SD components, M is the number of configured FD components, Q is the number of configured TD components, and S is the number of FD-TD component pairs per layer.

[0210] In some embodiments, the maximum number of non-zero combining coefficients does not exceed MS per layer, where S < 2LQ, L is the number of configured SD components, M is the number of configured FD components, Q is the number of configured TD components, and S is the number of SD-TD component pairs per layer.

[0211] In some embodiments, the maximum number of non-zero combining coefficients does not exceed QS per layer, where S < 2LM, L is the number of configured SD components, M is the number of configured FD components, Q is the number of configured TD components, and S is the number of SD-FD component pairs per layer.

[0212] Partitioning of Bits in the Bitmap of the CSI Report

[0213] In some embodiments, the bits of the bitmap are divided into two segments, where the first segment contains the first bits and is assigned to CSI group 1, and the second segment contains the remaining bits and is assigned to CSI group 2, and where S ≤ MQ.

[0214] In some embodiments, the bits of the bitmap are divided into two segments, where the first segment contains the first bits and is assigned to CSI group 1, and the second segment contains the remaining bits and are allocated to CSI group 2, and where S≤2LQ.

[0215] In some embodiments, the bits of the bitmap are divided into two segments, where the first segment contains the first bits and are assigned to CSI group 1, and the second segment contains the remaining bits and are allocated to CSI group 2, and where S≤2LM.

[0216] Partitioning of the number of non-zero coefficients in the CSI report

[0217] In some embodiments, in a CSI report, the amplitude values ​​or differential amplitude values ​​of K or fewer non-zero combined coefficients (e.g., where each amplitude coefficient of the non-zero coefficients is represented by the product of a reference or common amplitude coefficient and a differential amplitude coefficient) are quantized by A bits of common amplitude and B bits of differential amplitude.

[0218] In some embodiments, the total number of bits associated with the phase and amplitude (or differential amplitude values) of K or fewer non-zero combining coefficients is divided into two segments, where the first segment is allocated to CSI group 1 and the second segment is allocated to CSI group 2.

[0219] In some embodiments, in a CSI report, the phase values ​​of K or fewer non-zero combining coefficients are quantized using C bits respectively.

[0220] In some embodiments, the total number of bits used to quantize the differential magnitudes of K or fewer non-zero combining coefficients is divided into two or more segments and allocated to two or more CSI groups.

[0221] In some embodiments, the total number of bits associated with the differential magnitudes of K or fewer non-zero combining coefficients is divided into two segments, where the first segment includes at most bits and are assigned to CSI group 1, and the second segment includes at most bits and are allocated to CSI group 2.

[0222] In some embodiments, the total number of bits associated with a phase having K or fewer non-zero combining coefficients is divided into two segments, where the first segment includes at most bits and are assigned to CSI group 1, and the second segment includes at most bits and are allocated to CSI group 2.

[0223] In some embodiments, the total number of bits associated with the differential magnitudes of K or fewer non-zero combining coefficients is divided into two segments, where the first segment includes at most bits and are assigned to CSI group 1, and the second segment includes at most bits and are allocated to CSI group 2.

[0224] In some embodiments, the total number of bits associated with a phase having K or fewer non-zero combining coefficients is divided into two segments, where the first segment includes at most bits and are assigned to CSI group 1, and the second segment includes at most bits and are allocated to CSI group 2.

[0225] refer to Figure 4 , a method performed by a wireless device according to some of the aforementioned embodiments is described. The method is performed by a wireless device (or UE) and is configured to generate and transmit a CSI report in a wireless communication system, wherein the CSI report indicates a plurality of precoder vectors or matrices, wherein the precoder vectors or matrices are represented as a combination of spatial domain components, frequency domain components, and time domain components, and a set of linear combination coefficients for combining the spatial domain components, the frequency domain components, and the time domain components. The method comprises:

[0226] receiving (400) a CSI reporting configuration from a network node;

[0227] Determining (401) a number of precoder coefficients for an RI transmission layer of a precoder vector or matrix based on the received CSI report configuration information;

[0228] determining (402) a bitmap for indicating non-zero combining coefficients in the set of combining coefficients, assigning an order to bits of the bitmap, and assigning the same order to the plurality of combining coefficients;

[0229] dividing (403) the plurality of combining coefficients into two or more CSI groups having associated priority levels;

[0230] generating (404) a CSI report, the CSI report comprising the SD component, the FD component, an indication of the TD component, and the bitmap, wherein the CSI report comprises a CSI part 1 and a CSI part 2, wherein the CSI part 1 has a fixed payload size and comprises information indicating a payload size of the CSI part 2, and wherein the CSI part 2 comprises the combining coefficients of at least one of two or more of the CSI groups;

[0231] Uplink control information (UCI) including the CSI report is transmitted (405) or reported to the network node via an uplink (UL) channel.

[0232] In certain embodiments, the wireless device determines one or more spatial domain SD components, one or more frequency domain FD components, and one or more time domain TD components for the set of linear combination coefficients for the precoding vector or matrix, and wherein the SD, FD, and TD components are indicated in the CSI report.

[0233] In certain embodiments, the number S of FD-TD, SD-TD, or SD-FD component pairs is determined and indicated in the CSI report.

[0234] In certain embodiments, the value of S is indicated in CSI part 1 or CSI part 2 of the CSI report.

[0235] In certain embodiments, wherein the CSI report includes multiple CSI groups for UCI or CSI omission, and the bitmap includes RI bit fields, where the rth bit field is associated with the rth layer index and contains 2LS bits, and the bit ordering within each bit field is a function of the SD component index (l) and the FD-TD component pair index (s), given by u=2Ls+l or u=Sl+s, where l={0,…,2L-1}, s={0,…,S-1}.

[0236] In certain embodiments, wherein the CSI report includes multiple CSI groups for UCI or CSI omission, and the bitmap includes S bit fields, wherein the s-th bit field is associated with the s-th FD-TD component pair index and contains 2L·RI bits, and the bit ordering within each bit field is a function of the SD component index (l) and the layer index (r), given by u=2Lr+l or u=RI·l+r, where l={0,…,2L-1}, r={0,…,RI-1}.

[0237] In some embodiments, the mapping of associated FD components and TD components to the sth FD-TD component pair of each layer is given by s=Qm+q or s=Mq+m, where q∈{0,…,Q-1} is the TD component index and m∈{0,…,M-1} is the FD component index.

[0238] In certain embodiments, a bitmap is determined and used to indicate non-zero combining coefficients from a set of linear combining coefficients in a CSI report.

[0239] In certain embodiments, a CSI report includes multiple CSI groups for UCI or CSI omission.

[0240] In certain embodiments, the bitmap is assigned to the CSI group with the highest priority, or to two or more CSI groups for a CSI report.

[0241] In some embodiments, the number of SD components of the precoding matrix, L, is configured for the wireless device. In some embodiments, the number of TD components of the precoding matrix, Q, is configured for the wireless device. In some embodiments, the number of FD components of the precoding matrix, M, is configured for the wireless device.

[0242] In some embodiments, the phase and amplitude (or differential amplitude values) of the non-zero combining coefficients in the CSI report are divided into two segments, where the first segment is assigned to CSI group 1 and the second segment is assigned to CSI group 2 of the CSI report.

[0243] In certain embodiments, in a CSI report, the bits in the bitmap are divided into two segments, where the first segment is allocated to CSI group 1 and the second segment is allocated to CSI group 2 of the CSI report.

[0244] Ordering of bits in bitmap and ordering of combined coefficients

[0245] Option 1:

[0246] In some embodiments, the bitmap includes RI bit fields, where the rth bit field is associated with the rth layer index and includes 2LS bits, and each bit of the rth bit field is associated with one SD component index (l) of the 2L SD component indices and one FD-TD component pair index (s) of the S FD-TD component pair indices. In some embodiments, the ordering of the bits within each bit field is a function of the SD component index and the FD-TD component pair index, given by u=2Ls+l or u=Sl+s, where l={0,...,2L-1} and s={0,...,S-1}. In some embodiments, the mapping of the associated FD component and TD component to the sth FD-TD component pair of each layer is given by s=Qm+q or s=Mq+m, where q∈{0,...,Q-1} is the TD component index and m∈{0,...,M-1} is the FD component index. In some embodiments, the RI bit fields indexed with r={0, ..., RI-1} are sorted in increasing order from left to right.

[0247] Option 2:

[0248] In some embodiments, the bitmap includes RI bit fields, where the rth bit field is associated with the rth layer index and includes MS bits, and each bit of the rth bit field is associated with one FD component index (m) of the M FD component indices and one SD-TD component pair index (s) of the S SD-TD component pair indices. In some embodiments, the ordering of the bits within each bit field is a function of the FD component index and the SD-TD component pair index, given by u=Ms+m or u=Sm+s, where m={0,...,M-1} and s={0,...,S-1}. In some embodiments, the mapping of the associated SD component and TD component to the sth SD-TD component pair of each layer is given by s=2Lq+l or s=Ql+q, where q∈{0,...,Q-1} is the TD component index and l∈{0,...,2L-1} is the SD component index. In some embodiments, the RI bit fields indexed with r={0, ..., RI-1} are sorted in increasing order from left to right.

[0249] Option 3:

[0250] In some embodiments, the bitmap includes RI bit fields, where the r-th bit field is associated with the r-th layer index and includes QS bits, and each bit of the r-th bit field is associated with one TD component index (q) among the Q FD component indices and one SD-FD component pair index (s) among the S SD-FD component pair indices. In some embodiments, the ordering of the bits within each bit field is a function of the TD component index and the SD-FD component pair index, given by u=Qs+q or u=Sq+s, where q={0,...,Q-1} and s={0,...,S-1}. In some embodiments, the mapping of the associated SD component and FD component to the s-th SD-FD component pair of each layer is given by s=2Lm+l or s=Ml+m, where m∈{0,...,M-1} is the FD component index and l∈{0,...,2L-1} is the SD component index. In some embodiments, the RI bit fields indexed with r={0, ..., RI-1} are sorted in increasing order from left to right.

[0251] Option 4:

[0252] In some embodiments, the bitmap includes S bit fields, where the sth bit field is associated with the sth FD-TD component pair index and includes 2L·RI bits, and each bit of the sth bit field is associated with one SD component index (l) of the 2L SD component indices and one layer index (r) of the RI layers. In some embodiments, the ordering of the bits within each bit field is a function of the SD component index and the layer index, given by u=2Lr+l or u=RI·l+r, where r=0,…,RI-1 and l=0,…,2L-1. In some embodiments, the mapping of the associated FD component and TD component to the sth FD-TD component pair of each layer is given by s=Qm+q, or s=Mq+m, where m∈{0,…,M-1} is the FD component index and q∈{0,…,Q-1} is the TD component index. In some embodiments, the S bit fields indexed s={0,…,S-1} are ordered in increasing order from left to right. Option 5:

[0253] In some embodiments, the bitmap includes S bit fields, where the sth bit field is associated with the sth SD-TD component pair index and includes M·RI bits, and each bit of the sth bit field is associated with one FD component index (m) from the M FD component indices and one layer index (r) from the RI layers. In some embodiments, the ordering of the bits within each bit field is a function of the FD component index and the layer index, given by u=Mr+m or u=RI·m+r, where r=0,…,RI-1 and m=0,…,M-1. In some embodiments, the mapping of the associated SD component and TD component to the sth SD-TD component pair in each layer is given by s=2Lq+l or s=Ql+q, where l∈{0,…,2L-1} is the SD component index and q∈{0,…,Q-1} is the TD component index. In some embodiments, the S bit fields indexed s={0,…,S-1} are ordered in increasing order from left to right.

[0254] Option 6:

[0255] In some embodiments, the bitmap includes S bit fields, where the s-th bit field is associated with the s-th SD-FD component pair index and includes Q·RI bits, and each bit of the s-th bit field is associated with one TD component index (q) out of Q FD component indices and one layer index (r) out of RI layers. In some embodiments, the bit ordering within each bit field is a function of the TD component index and the layer index, given by u = Qr + q or u = RI·q + r, where r = 0, …, RI−1 and q = 0, …, Q−1. In some embodiments, the mapping of the associated SD component and FD component to the s-th SD-FD component pair of each layer is given by s = 2Lm + l or s = Ml + m, where l ∈ {0, ..., 2L−1} is the SD component index and m ∈ {0, …, M−1} is the FD component index. In some embodiments, the S bit fields with indices s = {0, …, S−1} are sorted in increasing order from left to right.

[0256] Option 7:

[0257] In some embodiments, the bitmap includes S bit fields, where S ≤ MQ, and the s-th bit field is associated with the s-th FD-TD component pair index and includes 2L·RI bits, and each bit of the s-th bit field is associated with one SD component index (l) out of 2L SD component indices and one layer index (r) out of RI layers. In some embodiments, the S bit fields with indices s = {0, …, S−1} are sorted in increasing order from left to right.

[0258] In some embodiments, the mapping of the associated FD and TD components to the s-th FD-TD component pair of each layer is given by s = Mq + m, where q ∈ {0, ..., Q−1} is the TD component index and m ∈ {0, …, M−1} is the FD component index.

[0259] In some embodiments, for S = MQ, the S FD-TD component pairs associated with the S bit fields are grouped into Q groups, where the q-th group includes M FD-TD component pairs associated with the same TD component.

[0260] In some embodiments, for S < MQ, the S FD-TD component pairs associated with the S bit fields are grouped into Q' groups, where the q-th group includes M or M' FD-TD component pairs associated with the same TD component, where Q′ < Q and M′ < M.

[0261] In some embodiments, for S < MQ, the S FD-TD component pairs associated with the S bit fields are grouped into Q groups, where the q-th group includes M or M' FD-TD component pairs associated with the same TD component, where Q′ < Q and M′ < M.

[0262] Option 8:

[0263] In some embodiments, the bitmap includes S bit fields, where S ≤ 2LQ, and the s-th bit field is associated with the s-th SD-TD component pair index and includes M·RI bits, and each bit of the s-th bit field is associated with one FD component index (m) out of M FD component indexes and one layer index (r) out of RI layers. In some embodiments, the S bit fields with indices s = {0, …, S−1} are sorted in increasing order from left to right.

[0264] In some embodiments, the mapping of the associated SD and TD components to the s-th SD-TD component pair of each layer is given by s = 2Lq + l, where q ∈ {0, ..., Q−1} is the TD component index and l ∈ {0, …, 2L−x} is the SD component index.

[0265] In some embodiments, for S = 2LQ, the S SD-TD component pairs associated with the S bit fields are grouped into Q groups, where the q-th group includes 2L SD-TD component pairs associated with the same TD component.

[0266] In some embodiments, for S < 2LQ, the S SD-TD component pairs associated with the S bit fields are grouped into Q' groups, where the q-th group includes 2L or 2L' SD-TD component pairs associated with the same TD component, where Q′ < Q and L′ < L.

[0267] In some embodiments, for S < 2LQ, the S SD-TD component pairs associated with the S bit fields are grouped into Q groups, where the q-th group includes 2L or 2L' SD-TD component pairs associated with the same TD component, where Q′ < Q and L′ < L.

[0268] In some embodiments, the S bit fields are grouped into Q or Q' bit fields, where the q-th bit field includes 2LM·RI bits. In some embodiments, the Q or Q' groups or bit fields are sorted with respect to increasing TD component indices. In some embodiments, the Q or Q' groups are sorted with respect to a permutation function of the Q TD component indices.

[0269] Sorting schemes for Option 7 and Option 8:

[0270] In some embodiments, the bit sorting within each q-th bit field is a function of the SD component index (l), the FD component index (m), and the layer index (r), given by u = 2LMr + Ml + m, where r = {0, …, RI}, m = {0, …, M−1}, and l = {0, …, 2L−1}.

[0271] In some embodiments, the bit ordering within each qth bit field is a function of the SD component index (l), the FD component index (m), and the layer index (r), given by u = 2LMr + 2Lm + l, where = {0,…, RI}, m = {0,…, M-1}, and l = {0,…, 2L-1}.

[0272] In some embodiments, the bit ordering within each qth bit field is a function of the SD component index (l), the FD component index (m), and the layer index (r), and is given by u = 2L·RI·m+RI·l+r, where = {0,…,RI}, m = {0,…,M-1}, and l = {0,…,2L-1}.

[0273] In some embodiments, the bit ordering within each qth bit field is a function of the SD component index (l), the FD component index (m), and the layer index (r), and is given by u = 2L·RI·m+2Lr+l, where = {0,…,RI}, m = {0,…,M-1}, and l = {0,…,2L-1}.

[0274] In some embodiments, the bit ordering within each qth bit field is a function of the SD component index (l), the FD component index (m), and the layer index (r), and is given by u = M·RI·l+Mr+m, where = {0,…,RI}, m = {0,…,M-1}, and l = {0,…,2L-1}.

[0275] In some embodiments, the bit ordering within each qth bit field is a function of the SD component index (l), the FD component index (m), and the layer index (r), and is given by u = M·RI·l+RI·m+r, where = {0,…,RI}, m = {0,…,M-1}, and l = {0,…,2L-1}.

[0276] Option 9:

[0277] In some embodiments, the bitmap includes S bit fields, where S≤MQ, and the s-th bit field is associated with the s-th FD-TD component pair index and includes s bits, and each bit of the s-th bit field is associated with one SD component index (l) of the 2L SD component indices and one layer index (r) of the RI layers. In some embodiments, the S bit fields with indices s={0, ..., S-1} are sorted in increasing order from left to right.

[0278] In some embodiments, the mapping of associated FD and TD components to the sth FD-TD component pair of each layer is given by s=Qm+q, where q∈{0,...,Q-1} is the TD component index and m∈{0,...,M-1} is the FD component index.

[0279] In some embodiments, for S = MQ, S FD-TD component pairs associated with S bit fields are grouped into M groups, where the nth group includes Q FD-TD component pairs associated with the same FD component.

[0280] In some embodiments, for S < MQ, S FD-TD component pairs associated with S bit fields are grouped into M' groups, where the mth group includes Q or Q' FD-TD component pairs associated with the same FD component, where Q' < Q and M' < M.

[0281] In some embodiments, for S < MQ, S FD-TD component pairs associated with S bit fields are grouped into M groups, where the mth group includes Q or Q' FD-TD component pairs associated with the same FD component, where Q' < Q and M' < M.

[0282] In some embodiments, S bit fields are grouped into M or M' bit fields, where the mth bit field includes ²LQ·RI bits. In some embodiments, the M or M' groups or bit fields are sorted with respect to an increasing FD component index. In some embodiments, the M or M' groups are sorted with respect to a permutation function of M FD component indices.

[0283] Option 10:

[0284] In some embodiments, the bitmap includes S bit fields, where S ≤ ²LM, and the sth bit field is associated with the sth SD-FD component pair index and includes Q·RI bits, and each bit of the sth bit field is associated with one TD component index (q) out of Q TD component indices and one layer index (r) out of RI layers. In some embodiments, the S bit fields with indices s = {0, …, S−1} are sorted in increasing order from left to right.

[0285] In some embodiments, the mapping of the associated SD and FD components to the sth SD-FD component pair of each layer is given by s = ²Lm + l, where l ∈ {0, ..., ²L−1} is the SD component index and m ∈ {0, …, M−1} is the FD component index.

[0286] In some embodiments, for S = ²LM, S SD-FD component pairs associated with S bit fields are grouped into M groups, where the mth group includes ²L SD-FD component pairs associated with the same FD component.

[0287] In some embodiments, for S < 2LM, the S SD-FD component pairs associated with S bit fields are grouped into M' groups, where the m-th group includes 2L or 2L' SD-FD component pairs associated with the same FD component, where L' < L and M' < M.

[0288] In some embodiments, for S < 2LM, the S SD-FD component pairs associated with S bit fields are grouped into M groups, where the m-th group includes 2L or 2L' SD-FD component pairs associated with the same FD component, where L' < L and M' < M.

[0289] In some embodiments, the S bit fields are grouped into M or M' bit fields, where the m-th bit field includes 2LQ·RI bits. In some embodiments, the M or M' groups or bit fields are sorted with respect to an increasing FD component index. In some embodiments, the M or M' groups are sorted with respect to a permutation function of M FD component indices.

[0290] Sorting schemes for option 9 and option 10:

[0291] In some embodiments, the bit sorting within each m-th bit field is a function of the SD component index (l), the TD component index (q), and the layer index (r), given by u = 2LQr + Ql + q, where r = {0,..., RI}, q = {0,..., Q - 1}, and l = {0,..., 2L - 1}.

[0292] In some embodiments, the bit sorting within each m-th bit field is a function of the SD component index (l), the TD component index (q), and the layer index (r), given by u = 2LQr + 2Lq + l, where r = {0,..., RI}, q = {0,..., Q -​​​​​​​​In some embodiments, the bit ordering within each m-th bit field is a function of the SD component index (l), the TD component index (q), and the layer index (r), given by u = Q·RI·l + Qr + q, where r = {0, …, RI}, q = {0, …, Q - 1}, and l = {0, …, 2L - 1}.

[0296] In some embodiments, the bit ordering within each m-th bit field is a function of the SD component index (l), the TD component index (q), and the layer index (r), given by u = Q·RI·l + RI·q + r, where r = {0, …, RI}, q = {0, …, Q - 1}, and l = {0, …, 2L - 1}.

[0297] Option 11:

[0298] In some embodiments, the bitmap includes S bit fields, where S ≤ 2LQ, and the s-th bit field is associated with the s-th SD-TD component pair index and includes M·RI bits, and each bit of the s-th bit field is associated with one FD component index (m) out of M FD component indices and one layer index (r) out of RI layers. In some embodiments, the S bit fields with indices s = {0, …, S - 1} are sorted in increasing order from left to right.

[0299] In some embodiments, the mapping of the associated SD and TD components to the s-th SD-TD component pair of each layer is given by s = Ql + q, where q ∈ {0, ..., Q - 1} is the TD component index and l ∈ {0, …, 2L - 1} is the SD component index.

[0300] In some embodiments, for S = 2LQ, the S SD-TD component pairs associated with the S bit fields are grouped into 2L groups, where the l-th group includes Q SD-TD component pairs associated with the same SD component.

[0301] In some embodiments, for S < 2LQ, the S SD-TD component pairs associated with the S bit fields are grouped into 2L' groups, where the l-th group includes Q or Q' SD-TD component pairs associated with the same SD component, where L' < L and Q' < Q.

[0302] In some embodiments, for S < 2LQ, the S SD-TD component pairs associated with the S bit fields are grouped into 2L groups, where the l-th group includes Q or Q' SD-TD component pairs associated with the same SD component, where L' < L and Q' < Q.

[0303] In some embodiments, S bit fields are grouped into 2L or 2L' bit fields, where the l-th bit field includes MQ·RI bits. In some embodiments, the 2L or 2l' groups or bit fields are sorted with respect to an increasing SD component index. In some embodiments, the 2l or 2L' groups are sorted with respect to a permutation function of L or 2l SD component indices.

[0304] Option 12:

[0305] In some embodiments, the bitmap includes S bit fields, where S ≤ 2LM, and the s-th bit field is associated with the s-th SD-FD component pair index and includes Q·RI bits, and each bit of the s-th bit field is associated with one TD component index (q) out of Q TD component indices and one layer index (r) out of RI layers. In some embodiments, the S bit fields with indices s = {0,..., S-1} are sorted in increasing order from left to right.

[0306] In some embodiments, the mapping of the associated SD and FD components to the s-th SD-FD component pair of each layer is given by s = Ml + m, where l ∈ {0,..., 2L-1} is the SD component index and m ∈ {0,..., M-1} is the FD component index.

[0307] In some embodiments, for S = 2LM, the S SD-FD component pairs associated with the S bit fields are grouped into 2L groups, where the l-th group includes M SD-FD component pairs associated with the same SD component.

[0308] In some embodiments, for S < 2LM, the S SD-FD component pairs associated with the S bit fields are grouped into 2L' groups, where the l-th group includes M or M' SD-FD component pairs associated with the same SD component, where L' < L and M' < M.

[0309] In some embodiments, for S < 2LM, the S SD-FD component pairs associated with the S bit fields are grouped into 2L groups, where the l-th group includes M or M' SD-FD component pairs associated with the same SD component, where L' < L and M' < M.

[0310] In some embodiments, S bit fields are grouped into 2L or 2L' bit fields, where the l-th bit field includes MQ·RI bits. In some embodiments, the 2L or 2L' groups or bit fields are sorted with respect to an increasing SD component index. In some embodiments, the 2L or 2L' groups are sorted with respect to a permutation function of L or 2L SD component indices.

[0311] Sorting schemes for Option 11 and Option 12:

[0312] In some embodiments, the bit ordering within each l-th bit field is a function of the FD component index (m), the TD component index (q), and the layer index (r), given by u = MQr + Qm + q, where r = {0,…, RI}, q = {0,…, Q-1}, and m = {0,…, M-1}.

[0313] In some embodiments, the bit ordering within each l-th bit field is a function of the FD component index (m), the TD component index (q), and the layer index (r), given by u = MQr + Mq + m, where r = {0,…, RI}, q = {0,…, Q-1}, and m = {0,…, m-1}.

[0314] In some embodiments, the bit ordering within each l-th bit field is a function of the FD component index (m), the TD component index (q), and the layer index (r), and is given by u = M·RI·q+Rm+r, where r = {0,…,RI}, q = {0,…,Q-1}, and m = {0,…,M-1}.

[0315] In some embodiments, the bit ordering within each l-th bit field is a function of the FD component index (m), the TD component index (q), and the layer index (r), and is given by u = M·RI·q+Mr+m, where r = {0,…,RI}, q = {0,…,Q-1}, and m = {0,…,M-1}.

[0316] In some embodiments, the bit ordering within each l-th bit field is a function of the FD component index (m), the TD component index (q), and the layer index (r), and is given by u = Q·RI·m+Qr+q, where r = {0,…,RI}, q = {0,…,Q-1}, and m = {0,…,M-1}.

[0317] In some embodiments, the bit ordering within each l-th bit field is a function of the FD component index (m), the TD component index (q), and the layer index (r), and is given by u = Q·RI·m+RI·q+r, where r = {0,…,RI}, q = {0,…,Q-1}, and m = {0,…,M-1}.

[0318] In some embodiments, the ordering of the S bit fields is based on any permutation function of the S SD-FD component pairs, where S ≤ 2LM. In some embodiments, the ordering of the S bit fields is based on any permutation function of the S SD-TD component pairs, where S ≤ 2LQ. In some embodiments, the ordering of the S bit fields may be based on any permutation function of the S FD-TD component pairs, where S ≤ MQ.

[0319] In order to perform the aforementioned procedures or method steps performed by a wireless device or UE, a wireless device is also provided. Figure 6 A simplified block diagram depicting a wireless device or UE 500 is illustrated. Wireless device 500 includes a processor 510 or processing circuitry or processing module or processor component 510; receiver circuitry or receiver module 540; transmitter circuitry or transmitter module 550; a memory module 520; and transceiver circuitry or transceiver module 530, which may include transmitter circuitry 550 and receiver circuitry 540. Wireless device 500 also includes an antenna system 560, which includes antenna circuitry for transmitting and receiving signals to and from at least a network node or other wireless device. The antenna system employs the beamforming techniques described above.

[0320] The wireless device 500 may be of any wireless access technology that supports beamforming technology, including 4G or LTE, LTE-A, 5G, Advanced 5G, or a combination thereof. The wireless device includes a processor and a memory, wherein the memory contains instructions executable by the processor, whereby the wireless device 500 is operable or configured to perform any of the aforementioned embodiments related to wireless devices.

[0321] The processing module / circuitry 510 includes a processor, a microprocessor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc., and the processing module / circuitry 510 may be referred to as a "processor." The processor 510 controls the operation of the wireless device and its components. The memory (circuitry or module) 520 includes random access memory (RAM), read-only memory (ROM), and / or other types of memory to store data and instructions that can be used by the processor 510. In general, it will be understood that in one or more embodiments, the wireless device 500 includes fixed or programmable circuitry that is configured to perform the operations of any of the embodiments disclosed herein.

[0322] In at least one such example, the processor 510 comprises a microprocessor, microcontroller, DSP, ASIC, FPGA, or other processing circuitry configured to execute computer program instructions from a computer program stored on a non-transitory computer-readable medium located within or accessible to the processing circuitry. Here, "non-transitory" does not necessarily imply permanent or unchanging storage and can include storage in working or volatile memory, but the term does imply storage with at least some degree of persistence. Execution of the program instructions specifically adapts or configures the processing circuitry to perform the operations described herein in connection with the wireless device. Furthermore, it is understood that the wireless device 500 may include other components.

[0323] The wireless device 500 executes instructions contained in the memory 520 via the processor 510, whereby the wireless device is capable of performing any of the embodiments described above with respect to actions performed by the wireless device, some of which are presented in the appended claims.

[0324] A computer program is also provided, comprising instructions which, when executed by the processor 510 of a wireless device, cause the processor 510 to perform a method according to any one of the above-described embodiments.

[0325] Also provided is a method, performed by a network node, for receiving a CSI report in a wireless communication system. The CSI report indicates a plurality of precoder vectors or matrices, the precoder vectors or matrices being represented as linear combinations of spatial domain components, frequency domain components, and time domain components, and a set of linear combination coefficients for combining the spatial domain components, the frequency domain components, and the time domain components. Figure 5 The main methodological steps are described, including:

[0326] Transmitting (501) a CSI reporting configuration to a wireless device (500); for causing the wireless device (500) to determine the number of precoder coefficients for an RI transmission layer of a precoder vector or matrix; determining a bitmap for indicating non-zero combining coefficients in the set of combining coefficients, assigning an order to bits of the bitmap, and assigning the same order to the plurality of combining coefficients; dividing the plurality of combining coefficients into two or more CSI groups with associated priority levels; generating and transmitting or reporting uplink control information (UCI) including the CSI report to the network node (600) via an uplink (UL) channel; and

[0327] The CSI report is received (502) from the wireless device (500), the CSI report comprising the SD component, the FD component, an indication of the TD component, and the bitmap, wherein the CSI report comprises a CSI part 1 and a CSI part 2, wherein the CSI part 1 has a fixed payload size and comprises information indicating the payload size of the CSI part 2, and wherein the CSI part 2 comprises the combining coefficients of at least one of two or more of the CSI groups, and wherein the content of the CSI report is determined by the wireless device (500) according to claim 1. The actions performed by the wireless device for determining the CSI report to be transmitted to the network node have been presented previously and will not be repeated here.

[0328] In order to perform the above-mentioned process or method steps performed by the network node, a network node is also provided. Figure 7 A block diagram depicting a network node 600 is illustrated. Network node 600 includes a processor 610 or processing circuitry or processing module or processor component 610; receiver circuitry or receiver module 640; transmitter circuitry or transmitter module 650; a memory module 620; and transceiver circuitry or transceiver module 630, which may include transmitter circuitry 650 and receiver circuitry 640. Network node 600 also includes an antenna system 660, which includes antenna circuitry for transmitting signals to and receiving signals from at least a wireless device. The antenna system employs the beamforming techniques described above.

[0329] The network node 600 may be of any radio access technology that supports beamforming technology, including 4G or LTE, LTE-A, 5G, advanced 5G, or a combination thereof. The network device includes a processor and a memory, wherein the memory contains instructions executable by the processor, whereby the network node 600 may be operated or configured to perform any of the embodiments related to the network node 600 as described above.

[0330] The processing module / circuitry 610 includes a processor, a microprocessor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc., and the processing module / circuitry 610 may be referred to as a "processor". The processor 610 controls the operation of the network node and its components. The memory (circuitry or module) 620 includes a random access memory (RAM), a read-only memory (ROM), and / or other types of memory to store data and instructions that can be used by the processor 610. In general, it will be understood that in one or more embodiments, the network node includes fixed or programmable circuits that are configured to perform the operations of any of the embodiments disclosed herein.

[0331] In at least one such example, the processor 610 comprises a microprocessor, microcontroller, DSP, ASIC, FPGA, or other processing circuitry configured to execute computer program instructions from a computer program stored in a non-transitory computer-readable medium that is within or accessible to the processing circuitry. Here, "non-transitory" does not necessarily mean permanent or unchanging storage and can include storage in working or volatile memory, but the term does mean storage that has at least some degree of persistence. Execution of the program instructions specifically adapts the processing circuitry or configures the processing circuitry to perform operations related to the network device of the present disclosure. In addition, it will be understood that the network node 600 may include other components. The network node 600 may also be viewed as a transmitter and receiver point (TRP).

[0332] The network node 600 executes instructions contained in the memory 620 via the processor 610, whereby the network node 600 is capable of performing any of the above-described embodiments related to actions performed by the network node, some of which are presented in the appended claim 8.

[0333] A computer program is also provided, comprising instructions which, when executed by a processor 610 of a network node, cause the processor 610 to perform a method according to any one of the embodiments of claim 8.

[0334] As previously mentioned, the embodiments described in this disclosure achieve several advantages, including significantly reducing the feedback overhead and computational complexity of wireless devices in codebook-based CSI reporting. Another advantage is reduced latency in CSI reporting.

[0335] Throughout this specification, references to "one example" or "exemplary" mean that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment of the present technology. Therefore, appearances of the phrases "in one example" or "exemplary" throughout this specification are not necessarily all referring to the same embodiment.

[0336] In this disclosure, the words "comprising" or "including" are used in a non-limiting sense, meaning "consisting at least of..." Although specific terms may be used herein, they are used in a generic and descriptive sense only and not for purposes of limitation. The embodiments herein may be applied to any wireless system, including LTE or 4G, LTE-A (or LTE-Advanced), 5G, Advanced 5G, WiMAX, WiFi, satellite communications, television broadcasting, etc.

Claims

1. A method performed by a wireless device (500) for generating and reporting or transmitting a channel state information (CSI) report in a wireless communication system, wherein the CSI report indicates a plurality of precoder vectors or matrices, wherein the precoder vectors or matrices are represented as linear combinations of spatial domain (SD) components, frequency domain (FD) components, and time domain (TD) components, and a set of linear combining coefficients for combining the spatial domain components, the frequency domain components, and the time domain components, the method comprising: receiving (400) a CSI reporting configuration from a network node (600); Determining (401) a number of precoder coefficients for a rank index (RI) transmission layer of a precoder vector or matrix based on the received CSI reporting configuration; determining (402) a bitmap for indicating non-zero combining coefficients in the set of linear combining coefficients, assigning an order to bits of the bitmap, and assigning the same order to the plurality of combining coefficients; dividing (403) the plurality of combining coefficients into two or more CSI groups having associated priority levels; generating (404) a CSI report, the CSI report comprising the SD component, the FD component, an indication of the TD component, and the bitmap, wherein the CSI report comprises a CSI part 1 and a CSI part 2, wherein the CSI part 1 has a fixed payload size and comprises information indicating a payload size of the CSI part 2, and wherein the CSI part 2 comprises the combining coefficients of at least one of two or more of the CSI groups; as well as Uplink control information (UCI) including the CSI report is transmitted (405) or reported to the network node (600) via an uplink (UL) channel.

2. The method according to claim 1, wherein the wireless device determines one or more spatial domain SD components, one or more frequency domain FD components, and one or more time domain TD components for the set of linear combining coefficients for the precoding vector or matrix, and wherein the SD, FD and TD components are indicated in the CSI report.

3. The method according to claim 1 or 2, wherein the number S of FD-TD component pairs, SD-TD component pairs or SD-FD component pairs is derived from parameters M and Q, where M is the number of configured FD components of the precoding matrix and Q is the number of configured TD components of the precoding matrix.

4. The method according to any of the preceding claims, wherein the CSI report includes multiple CSI groups for UCI or CSI omission, and the bitmap includes S bit fields, wherein the s-th bit field is associated with the s-th FD-TD component pair index and contains 2L·RI bits.

5. A method according to claim 4, wherein the bit ordering within each bit field is a function of the SD component index (l) and the layer index (r), given by u=RI·l+r, where l={0,…,2L-1} and r={0,…,RI-1}.

6. The method of claim 5, wherein the mapping of the associated FD and TD components to the sth FD-TD component pair of each layer is given by s=Mq+m, where q∈{0,…,Q-1} is the TD component index and m∈{0,…,M-1} is the FD component index. 7 . The method of claim 5 , wherein the ordering of the S bit fields is based on an arbitrary permutation function of the S FD-TD component pairs, where S≤MQ.

8. The method of claim 4, wherein the S bit fields are grouped into Q groups, wherein the qth group contains M FD-TD component pairs associated with the same TD component, and wherein the Q groups are ordered with respect to increasing TD component indices.

9. The method of claim 7, wherein the bit ordering in each q-th group is given by u = 2L·RI·m+RI·l+r, where r = {0, ..., RI}, m = {0, ..., M-1}, and l = {0, ..., 2L-1}.

10. A method according to any one of the preceding claims, wherein the bits of the bitmap are divided into two segments, wherein the first segment contains the first bits and are allocated to CSI group 1, and the second segment contains the remaining bits and are allocated to CSI group 2, and where S≤MQ.

11. The method of claim 1 , wherein the differential amplitude values ​​of the K or fewer non-zero combining coefficients in the CSI report are quantized using B bits of differential amplitude value, and wherein the total number of bits associated with the differential amplitude values ​​of the K or fewer non-zero combining coefficients is divided into two segments, wherein the first segment contains at most bits and are allocated to CSI group 1, and the second segment contains at most bits and are allocated to CSI group 2.

12. The method of claim 1 , wherein the phase values ​​of K or fewer non-zero combining coefficients in the CSI report are quantized using C bits, and wherein the total number of bits associated with the phase values ​​of the K or fewer non-zero combining coefficients is divided into two segments, wherein the first segment contains at most bits and are allocated to CSI group 1, and the second segment contains at most bits and are allocated to CSI group 2.

13. A method performed by a network node (600) for receiving a channel state information (CSI) report in a wireless communication system, the CSI report indicating a plurality of precoder vectors or matrices, the precoder vectors or matrices being represented as linear combinations of spatial domain components, frequency domain components, and time domain components, and a set of linear combining coefficients for combining the spatial domain components, the frequency domain components, and the time domain components, the method comprising: Transmitting (501) a CSI reporting configuration to a wireless device (500); for causing the wireless device (500) to determine a number of precoder coefficients for an RI transmission layer of a precoder vector or matrix; determining a bitmap for indicating the non-zero combining coefficients in the set of linear combining coefficients, assigning an order to the bits of the bitmap, and assigning the same order to the plurality of combining coefficients; dividing the plurality of combining coefficients into two or more CSI groups having associated priority levels; transmitting or reporting uplink control information (UCI) including the CSI report to the network node (600) via an uplink (UL) channel; as well as A CSI report is received (502) from the wireless device (500), the CSI report comprising the SD component, the FD component, an indication of the TD component, and the bitmap, wherein the CSI report comprises a CSI part 1 and a CSI part 2, wherein the CSI part 1 has a fixed payload size and comprises information indicating the payload size of the CSI part 2, and wherein the CSI part 2 comprises the combining coefficients of at least one of two or more of the CSI groups.

14. A network node (600) comprising a processor (610) and a memory (620), the memory (620) containing instructions executable by the processor (610) such that the network node (600) performs the method of claim 8.

15. A wireless device (500) comprising a processor (510) and a memory (520), the memory (520) containing instructions executable by the processor (510) such that the wireless device (500) performs the method of any one of claims 1-7.

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