Methods and apparatuses for precoding and reporting in a wireless communicstion system

Abstract

The embodiments of the present invention relate to methods and apparatuses, in the form of a wireless device (300), and a network node (400) In some embodiments, the method performed by the wireless device comprises receiving (501) from a network node, a configuration indicating reference signals. The method further comprises determining (502) based on the configuration one or more beam vectors and one or more precoding coefficients of a precoding matrix, wherein the one or more beam vectors and precoding coefficients are determined with respect to one or more parameters derived from the reference signals. The method further comprises generating (503) a report indicating the precoding matrix, and reporting (504) to the network node the report.

Description

[0001] METHODS AND APPARATUSES FOR PRECODING AND REPORTING IN A WIRELESS COMMUNICSTION SYSTEM

[0002] TECHNICAL FIELD

[0003] The present invention relates to the field of communication technologies, and in particular, to a method, a wireless device and a network node for configurations, measurements, and reporting of reference signal resources.

[0004] BACKGROUND

[0005] The third-generation partnership project (3GPP) provides for the fifth generation (5G) and will provide for the sixth generation (6G) the complete system specification of the network architecture, which includes the radio access network (RAN), core transport network (CN) and service capabilities. The radio access technology (RAT) in 5G (and 6G) mobile communications systems provides (or will provide) a higher level of performance and flexibility than the previous generations of mobile communications systems. 5G mobile communications have been driven by the need to provide ubiquitous connectivity for applications as diverse automotive communication, remote control with feedback, video downloads, as well as data applications for Internet-of-Things (loT) devices, machine type communication (MTC) devices, etc. The 5G communication technology brings several main benefits, such as higher speed, lower latency and increased connectivity. This trend will be continued in 6G, and in addition, new technologies such as integrated communication and sensing will possibly be introduced. Radio sensing, as a part of the integrated communication and sensing, can be used by a wireless device or a network node in the communication network to analyze reflections and scattering of transmitted signals to yield knowledge of the physical surroundings. The information of physical surroundings can be used, for example, to enhance resource and beam management in communications systems and hence system performance.

[0006] There is a need for improved radio sensing in mobile communications systems, such as 5G NR or 6G systems.

[0007] SUMMARY

[0008] It is an objective of the embodiments herein to provide methods and apparatuses for reporting information related to signal precoding for radio sensing for wireless communications networks such as advanced 5G and 6G networks.

[0009] According to a first aspect of some embodiments herein, there is provided a method performed by a wireless device in a wireless communication system. A wireless communication system may be referred to as a wireless communications network, or a mobile communication(s) system. The method comprises:

[0010] - receiving from a network node, a configuration indicating reference signals,

[0011] - determining based on the configuration one or more beam vectors and one or more precoding coefficients of a precoding matrix, wherein the one or more beam vectors and precoding coefficients are determined with respect to one or more parameters derived from the reference signals,

[0012] - generating a report indicating the precoding matrix, and

[0013] - reporting to the network node the report.

[0014] According to a second aspect of some embodiments herein, there is provided a method performed by a wireless device in a wireless communication system. The method comprises: receiving from a network node a configuration indicating reference signals, determining a precoding matrix based on the configuration and information related to one or more timing and / or frequency parameters and / or beam parameters, generating a report indicating the precoding matrix, and reporting to the network node the report.

[0015] According to a third aspect of some embodiments herein, there is provided a method performed by a wireless device in a wireless communication system. The method comprises: receiving from a network node, a configuration indicating a number of reference signals, or antenna ports, determining based on the configuration a first and a second precoding matrix, and selecting one or more beam vectors, wherein each precoding matrix is based on the one or more selected beam vectors and precoding coefficients, and wherein one of more beam vectors of the first precoding matrix are identical to one or more beam vectors of the second precoding matrix, generating a report indicating at least the one or more selected beam vectors associated with the first and second precoding matrices, and reporting to the network node the report.

[0016] According to fourth aspect of some embodiments herein, there is provided a method performed by a network node (e.g., a gNB) in a wireless communication system. The method comprises: transmitting to a wireless device a configuration indicating reference signals, for enabling the wireless device to:

[0017] - determine based on the configuration one or more beam vectors and one or more precoding coefficients of a precoding matrix, wherein the one or more beam vectors and precoding coefficients are selected with respect to one or more parameters derived from the reference signals,

[0018] - generate a report indicating the precoding matrix, and receiving the report from the wireless device.

[0019] According to a fifth aspect of some embodiments herein, there is provided a method performed by a network node (e.g., a gNB) in a wireless communication system. The method comprises: transmitting to a wireless device a configuration indicating reference signals, for enabling the wireless device to: determine a precoding matrix based on the configuration and information related to one or more timing and / or frequency parameters and / or beam parameters, generate a report indicating the precoding matrix, and receiving the report from the wireless device.

[0020] According to a sixth aspect of some embodiments herein, there is provided a method performed by a network node (e.g., a gNB) in a wireless communication system. The method comprises: transmitting to a wireless device, a configuration indicating a number of reference signals, or antenna ports, for enabling the wireless device to: determine based on the configuration a first and a second precoding matrix, and select one or more beam vectors, wherein each precoding matrix is based on the one or more selected beam vectors and precoding coefficients, and wherein one of more beam vectors of the first precoding matrix are identical to one or more beam vectors of the second precoding matrix, generate a report indicating at least the one or more selected beam vectors associated with the first and second precoding matrices, and receiving the report from the wireless device.

[0021] According to seventh aspect of embodiments herein, there is also provided a wireless device (e.g., a UE) comprising a processor and a memory containing instructions executable by the processor, whereby the wireless device is operative or configured to perform any one of the embodiments presented in the detailed description related to the actions performed by the wireless device.

[0022] According to an eighth aspect of embodiments herein, there is provided a network node comprising a processor and a memory containing instructions executable by the processor, whereby said network node is operative or configured to perform any one of the embodiments presented in the detailed description related to the actions performed by the network node.

[0023] There is also provided a computer program comprising instructions which when executed on at least one processor of the wireless device (e.g., a UE), cause the at least one processor to carry out the actions or method steps presented herein.

[0024] There is also provided a computer program comprising instructions which when executed on at least one processor of the network node, cause the at least one processor to carry out the method steps presented herein.

[0025] A carrier is also provided containing the computer program, wherein the carrier is one of a computer readable storage medium, an electronic signal, optical signal, or a radio signal.

[0026] Advantageously, detection performance and accuracy of targets or scatterers at a wireless device in mobile communications systems, such as 5G NR or 6G systems, are improved.

[0027] Additional advantages of the embodiments herein are provided in the detailed description of this disclosure.

[0028] BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Embodiments of the present invention are now described in further detail with reference to the accompanying drawings, in which:

[0030] Fig. 1 shows a schematic representation of a wireless communications network, wherein embodiments herein may be applied;

[0031] Fig. 2 shows a block-based model of a MIMO DL transmission using codebook-based- precoding in accordance with LTE Release 8;

[0032] Fig. 3(a) illustrates three selected components of a channel response determined from one or more reference signals by the wireless device, wherein the channel response is a channel impulse response according to some embodiments herein; Fig. 3(b) illustrates the three selected components of the corresponding channel response determined by the wireless device after applying the reported precoding matrix to one or more reference signals by the network node.

[0033] Fig. 4(a) illustrates a single selected component of a channel response determined from one or more reference signals by the wireless device, wherein the channel response is a channel impulse response according to some embodiments herein;

[0034] Fig. 4(b) illustrates the corresponding channel response determined by the wireless device after applying the reported precoding matrix to one or more reference signals by the network node.

[0035] Fig. 5 illustrates a flowchart of a method performed by a wireless device (e.g., a UE) according to some embodiments herein;

[0036] Fig. 6 illustrates a flowchart of a method performed by a network node (e.g., a gNB) according to some embodiments herein;

[0037] Fig. 7 is a block diagram depicting a wireless device (e.g., a UE) according to exemplary embodiments herein.

[0038] Fig. 8 is a block diagram depicting a network node (e.g., a gNB) according to exemplary embodiments herein.

[0039] DETAILED DESCRIPTION

[0040] In the following, a detailed description of the exemplary embodiments is described in conjunction with the drawings, in several scenarios to enable easier understanding of the solution(s) described herein.

[0041] Figure 1 illustrates a simplified schematic view of an example of a wireless communications network 100 including a core network (CN) 110 and a radio access network (RAN) 120. The RAN 120 is shown including a plurality of network nodes or radio base stations or transmission reception points, TRP, which may also be called next generation NodeB (gNB). Three radio base stations are indicated as gNB1 , gNB2 and gNB3. Each gNB serves an area called a coverage area or a cell. Figure 1 illustrates 3 cells 121 , 122 and 123, each served by its own gNB, gNB1 , gNB2 and gNB3, respectively. It should be mentioned that the network 100 may include any number of cells and gNBs. The radio base stations, or network nodes serve users within a cell. In 4G or LTE, a radio base station is called an eNB. In 3G or UMTS, a radio base station is called an eNodeB, and BS in other radio access technologies. In NR systems, the term “cell” and gNB, new radio base station (NR BS), 5G N B, access point (AP), or TRP may be interchangeable. A user equipment (UE) may be a wireless or a mobile terminal device or a stationary communication device. A wireless device may be a UE, an Internet of Things (loT) device, a Machine-type communication (MTC) device, etc. loT devices may include wireless sensors, software, actuators, and computer devices. The loT devices can be imbedded into mobile devices, motor vehicle, industrial equipment, environmental sensors, medical devices, aerial vehicles and more, equipped with network connectivity that enables these devices to collect and exchange data across an existing network infrastructure.

[0042] Referring back to Figure 1 , each cell as shown includes UEs and loT devices. gNB1 in cell 121 serves UE1 121A, UE2 121 B and loT device 121C. Similarly, gNB2 in cell 121 serves UE3 122A, UE4 122B and loT device 122C, and gNB3 in cell 123 serves UE5 123A, UE6 123B and loT device 123C. The wireless communications network 100 may include any number of UEs and loT devices or any other types of devices. The devices communicate with the serving gNB(s) in the uplink and the gNB(s) communicate with the devices in the downlink. The respective base stations gNB1 to gNB3 may be connected to the CN 110, e.g., via the S1 interface, via respective backhaul links 111 , 121 D, 122D, 123D, which are schematically depicted in Fig. 1 by the arrows pointing to “core”. The core network 110 may be connected to one or more external networks, such as the Internet. The gNBs may be connected to each other via the S1 interface or the X2 interface or the XN interface in 5G, via respective interface links 121 E, 122E and 123E, which is depicted in the figure by the arrows pointing to gNBs.

[0043] For data transmission, a physical resource grid may be used. The physical resource grid may comprise a set of resource elements (REs) to which various physical channels and physical signals are mapped. For example, the physical channels may include the physical downlink, uplink and / or sidelink (SL) shared channels (PDSCH, PUSCH, PSSCH) carrying user specific data, also referred to as downlink, uplink or sidelink payload data, the physical broadcast channel (PBCH) carrying for example a master information block (MIB) and a system information block (SIB), the physical downlink, uplink and / or sidelink control channels (PDCCH, PUCCH, PSCCH) carrying for example the downlink control information (DCI), the uplink control information (UCI) or the sidelink control information (SCI). For the uplink, the physical channels may further include the physical random-access channel (PRACH or RACH) used by UEs for accessing the network once a UE is synchronized and obtains the MIB and SIB. The physical signals may comprise reference signals (RS), synchronization signals (SSs) and the like. The resource grid may comprise a frame or radio frame having a certain duration, like 10 milliseconds, in the time domain and having a given bandwidth in the frequency domain. The radio frame may have a certain number of subframes of a predefined length, e.g., 2 subframes with a length of 1 millisecond. Each subframe may include two slots of a number of OFDM symbols depending on the cyclic prefix (CP) length. In 5G, each 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, e.g., when utilizing shortened transmission time intervals (TTIs) or a mini-slot / non-slot-based frame structure comprising just a few OFDM symbols. Slot aggregation is supported in 5G NR and hence data transmission can be scheduled to span one or multiple slots. Slot format indication informs a UE whether an OFDM symbol is downlink, uplink or flexible.

[0044] The wireless communications network may be any single-tone or multicarrier system using frequency-division multiplexing, like the orthogonal frequency-division multiplexing (OFDM) system, the orthogonal frequency-division multiple access (OFDMA) system, or any other Discrete Fourier Transform (DFT) based signal with or without CP, e.g., DFT-spread OFDM (DFT-s-OFDM). Other waveforms, like non-orthogonal waveforms for multiple access, e.g., filter-bank multicarrier (FBMC), generalized frequency division multiplexing (GFDM) or universal filtered multi carrier (LIFMC), may also be used. The wireless communication system may operate, e.g., in accordance with the LTE-Advanced Pro standard, the 5G or NR (New Radio) standard or any other standard using any of the aforementioned waveforms.

[0045] The wireless communications network depicted in Figure 1 may be a heterogeneous network having two distinct overlaid networks, a network of macro cells with each macro cell including a macro base station, like base station gNB1 to gNB3, and a network of small cell base stations (not shown in Figure 1), like femto- or pico-base stations. In addition to the above-described wireless network also non-terrestrial wireless communication networks exist including spaceborne transceivers, like satellites, and / or airborne transceivers, like unmanned aircraft systems. The non-terrestrial wireless communication network or system may operate in a similar way as the terrestrial system described above with reference to Figure 1 , for example in accordance with the LTE-advanced pro standard, the 5G or NR, or the future 6G standard.

[0046] In the wireless communications network such as the one depicted schematically in Figure 1 , multi-antenna techniques may be used, e.g., in accordance with LTE, NR or any other communication system, to improve user data rates, link reliability, cell coverage and network capacity. To support multi-stream or multi-layer transmissions, linear precoding is used in the physical layer of the communication system. Linear precoding is performed by a precoding matrix which maps layers of data to antenna ports. The precoding may be seen as a generalization of beamforming, which is a technique to spatially direct or focus a data transmission towards an intended receiver. The precoding matrix to be used at the gNB to map the data to the transmit antenna ports is decided using channel state information, CSI. In the wireless communications network system as described above, such as LTE or New Radio (5G), various physical channels are defined for the communication of data payload and control information. In addition, various reference signals are also designed for purposes such as link adaptation and management, demodulation, frame synchronization, cell search, phase tracking, among others. A gNodeB (gNB) or eNodeB (eNB), or transmission reception point, TRP, which could also be a base station, transmits to one or more users in the downlink. A user equipment (UE) or mobile terminal transmits to one or more base stations in the uplink. In the sidelink, two or more user equipments may be involved in communication. The data payload is transmitted via the physical downlink shared channel (PDSCH) in the downlink (DL), via the physical uplink shared channel (PLISCH) in the uplink (UL) and via the physical sidelink shared channel (PSSCH) in the sidelink (SL), of a wireless network. The control information is typically transmitted via the physical downlink control channel (PDCCH) or the enhanced PDCCH (ePDCCH) in certain LTE releases in the downlink (DL), via the physical uplink control channel (PUCCH) in the uplink (UL) and via the physical sidelink control channel (PSCCH) in the sidelink (SL), of a wireless network.

[0047] The physical broadcast channel (PBCH) is transmitted along with the synchronization signals (SS) in the downlink as a SS / PBCH block to aid in cell search and downlink synchronization. The SS / PBCH block may also be called as a synchronization signal block (SSB). The physical sidelink broadcast channel (PSBCH) in the sidelink is similar in structure and functionality to the PBCH. The physical random-access channel (PRACH) in the uplink is characterized by the PRACH preamble and is used for uplink synchronization.

[0048] The PDSCH, PDCCH, PBCH, PUSCH, PUCCH, PSSCH, PSCCH and PSBCH are provided with DeModulation Reference Signals (DMRS) for coherent demodulation of the channel. The number of DM RS antenna ports during a given instance of transmission of the channel is equal to the number of layers transmitted. A layer of the transmission of a channel can be referred to using the DMRS port associated with it. In LTE, the common reference signals (CRS) may be used for DL demodulation, channel estimation, etc.

[0049] The channel state information reference signal (CSI-RS) is transmitted with a reduced density in the time and frequency domain compared to CRS and plays a crucial role in initiating, maintaining, adapting, and recovering communication links. The following are some uses of the CSI-RS in a wireless network: estimation of the DL channel for adaptation of link parameters such a spatial precoder, modulation order and coding scheme, measurement and reporting of suitable spatial beam(s) for communication, tracking of various parameters required for communication such as average delay, delay spread, Doppler shift / spread, DL pathloss, etc., and recovering a link after its “failure”. 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 a non-precoded CSI-RS, a one-to-one mapping between a CSI-RS port and a transceiver unit, TXRLI, of the antenna array at the gNB is utilized. Therefore, non-precoded CSI-RS provides a cell-wide coverage where the different CSI-RS ports have the same beam direction and beam width. For beamformed / precoded UE-specific or non-U E-specific CSI-RS, a beamforming operation is applied over a single antenna port or over multiple antenna ports to have several narrow beams with high gain in different directions and, therefore, no cell-wide coverage.

[0050] In a wireless communications network system employing time division duplexing, TDD, due to channel reciprocity, the CSI is available at the base station (e.g., gNB). However, when employing frequency division duplexing, FDD, due to the absence of channel reciprocity, the channel is estimated at the UE and the estimate is fed back to the base station (e.g., gNB). Figure 2 shows a block-based model of a Multiple Input Multiple Output (MIMO) DL transmission using codebook-based-precoding in accordance with LTE release 8. Figure 2 shows schematically the base station 200 (e.g., gNB), the user equipment, UE, 202 and the channel 204, like a radio channel for a wireless data communication between the base station 200 and the user equipment 202. The base station includes an antenna array ANTT having a plurality of antennas or antenna elements, and a precoder 206 receiving a data vector 208 and a precoder F from a codebook 210. The term “precoder” means, without limitation, a precoding matrix or a precoder matrix. The channel 204 may be described by the channel tensor / matrix 212. The user equipment 202 receives the data vector 214 via an antenna or an antenna array ANTR having a plurality of antennas or antenna elements. A feedback channel 216 between the user equipment 202 and the base station 200 is provided for transmitting feedback information. The previous releases of 3GPP up to Release 18 support the use of several downlink reference symbols (such as CSI-RS) for CSI estimation at the UE.

[0051] In FDD systems (up to Rel. 18), the estimated channel at the UE is reported to the gNB implicitly where the CSI report transmitted by the UE over the feedback channel includes the rank index (Rl), the precoding matrix index (PMI) and the channel quality index (CQI) (and the CRI from Rel. 13) allowing, at the gNB, to decide the precoding matrix, and the modulation order and coding scheme (MCS) of the symbols to be transmitted. The PMI and the Rl are used to determine the precoding matrix from a predefined set of matrices, also referred to as codebook. A codebook comprises vectors or indices indicating vectors. A UE may select a vector from the codebook and indicates the selected vector or the index of the selected vector (i.e. , a precoding vector) in the CSI report. The codebook, e.g., in accordance with LTE, may be a look-up table with matrices in each entry of the table, and the PMI and Rl from the UE decide from which row and column of the table the precoding matrix to be used is obtained. The precoders and codebooks are designed up to Rel. 18 for gNBs equipped with one- dimensional Uniform Linear Arrays (ULAs) having dual-polarized antennas (in total Nt= 2N±antennas or antenna ports), or with two-dimensional Uniform Planar Arrays (UPAs) having dual-polarized antennas at N±N2positions (in total Nt= 2N N2antennas or antenna ports). The ULA allows controlling the radio wave in the horizontal (azimuth) direction only, so that azimuth-only beamforming at the gNB is possible, whereas the UPA supports transmit beamforming on both vertical (elevation) and horizontal (azimuth) directions, which is also referred to as full-dimension (FD) MIMO. The codebook, e.g., in the case of massive antenna arrays such as FD-MIMO, may be a set of beamforming weights that forms spatially separated electromagnetic transmit / receive beams using the array response vectors of the array. The beamforming weights (also referred to as the array steering vectors) of the array are amplitude gains and phase adjustments that are applied to the signal fed to the antennas (or the signal received from the antennas) to transmit (or obtain) a radiation towards (or from) a particular direction. The components of the precoding matrix are obtained from the codebook, and the PM I and the Rl are used to read the codebook and obtain the precoder. The array steering vectors may be described by the columns of a two-dimensional Discrete Fourier Transform (DFT) matrix when ULAs or UPAs are used for signal transmission.

[0052] The precoder matrices used in the Type-1, Type-1 multi-panel and Type-ll CSI reporting schemes in 3GPP NR standards are defined by a dual-stage structure (i.e., two components codebook), F = F1F2. The first component or the so-called first stage precoder or matrix, Fl tis used to select a number of beam vectors from a Discrete Fourier Transform-based (DFT- based) matrix, which is also called the spatial codebook. Moreover, the first stage precoder, Fltcorresponds to a wide-band matrix and contains a number of spatial beamforming vectors (the so-called spatial beams) selected from a DFT-based codebook matrix for the two polarizations of the antenna array. The second component or the so-called second stage precoder is used to combine the selected beam vectors. This means the second stage precoder or matrix, F2, corresponds to a selection / combining / co-phasing matrix to select / combine / co-phase the beams defined in F±. For rank-v transmission, F contains v vectors, wherein v denotes the transmission rank, where the entries of each vector are chosen to combine single or multiple beams within each polarization. The selection of the matrices F±and F2is performed by the wireless device (e.g., a UE) based on reference signals such as CSI-RS and the knowledge of the channel conditions. The selected matrices are indicated in a CSI report in the form of a Rl (the Rl denotes the rank of the precoding matrix) and a PM I and are used at the gNB to update the multi-user precoder for the next transmission time interval.

[0053] The present invention proposes methods and apparatuses for reporting information related to signal precoding for radio sensing at a wireless device (e.g., a user equipment, UE), with the aim to improve the detection performance of target(s) or scatterer(s) at a wireless device in mobile communications systems, such as 5G NR or 6G systems. A method is proposed for selecting and reporting a precoding matrix that improves the detection of selected components of a channel response determined at the wireless device. When applying the selected precoding matrix to one or more reference signals, some components of the corresponding channel response can be detected by the wireless device with a higher probability or reliability. In some examples, the selected components are associated with reflector(s), scatterer(s) or target(s) in the surrounding of the wireless device and / or network node. In some examples, these targets and / or reflectors are blocking objects, humans, bicycles, or any kind of vehicles, robots, UAV, machines, drones, parts of city building elements, walls, benches, etc. Based on the determined components of the channel response and / or the knowledge of the position of the wireless device, the wireless device or base station can determine information related to the position, and / or movement and / or direction of the reflector(s), scatterer(s) or target(s) associated with the components of the channel response. Moreover, to reduce the signaling overhead for reporting the precoding matrix from the wireless device to the network node (e.g., base station or TRP), it is proposed that the precoding matrix is selected from one or more pre-defined set of vectors and / or matrices and / or codebooks.

[0054] The term ‘higher layer’ in the following, when used in isolation, denotes any communication layer above the physical layer in the protocol stack. When the term is used in connection with a specific layer, it denotes any communication in the protocol stack above said layer.

[0055] The term serving cell and carrier component (CO) may be used interchangeably in this disclosure as a serving cell configured for a UE and is usually a separate physical carrier centered around a particular carrier frequency. Depending on the frequency of a component carrier / serving cell, the size of the cell and the beamformed reference signals may vary.

[0056] The term ‘PDxCH’ or ‘PDXCH’ may indicate either the physical downlink shared channel (PDSCH) or the physical downlink control channel (PDCCH), while ‘PLIxCH’ or ‘PLIXCH’ may indicate either the physical uplink shared channel (PLISCH) or the physical uplink control channel (PUCCH). The term ‘PxxCH’ or ‘PXXCH’ may denote a PDSCH, a PDCCH, a PUSCH, a PRACH, a PBCH, a PSSCH, or a PSCCH.

[0057] The phrase ‘fixed / predetermined / provided in the specifications’ in this invention disclosure may mean the following: one or more rules and / or methods and / or particulars regarding certain parameter(s) are provided in the standard specifications that the UE and / or any network node is supposed to follow or implement. The term ‘configured’ may mean the following: one or more rules and / or methods and / or particulars regarding one or more parameters as provided in the standard specifications that the UE is supposed to follow or implement are provided to the UE by one or more network entities, e.g., via higher layer signaling, like radio resource control, RRC, signaling.

[0058] A precoding vector or matrix is determined by the wireless device based on measurements of one or more received reference resources (e.g., channel state information reference signal, CSI-RS, resource). The reference resources are provided by another wireless device or a network node. A CSI-RS resource or a number of CSI-RS reference resources, K, is / are configured to the wireless device via a configuration information from another wireless device or the network node. The wireless device performs channel state information, CSI, measurements on the one or more configured CSI-RS resources (e.g., K) received over one or more slots, T, and to determine based on the CSI measurements a precoding vector or a precoding matrix (in short, a precoder). The precoding vector or matrix is indicated via a precoding matrix identifier, PM I, in the CSI report. The CSI report is transmitted by the wireless device to the other wireless device or a network node. A reference (e.g., CSI-RS) resource may be associated with a subset of 2N±N2antenna ports or CSI-RS ports, wherein N±and N2are the number of antenna ports in a first and a second dimension, respectively. In some examples, K = 1 and T = 1. In some other examples, K > 1 and T = 1. In some other examples, K > 1 and T > 1.

[0059] In certain embodiments, the PMI indicates a precoding matrix, comprising a plurality of precoding vectors for v transmission layers, wherein each precoding vector is associated with a transmission layer.

[0060] In certain embodiments, the wireless device is configured to indicate a precoding matrix and the rank of the precoding matrix (in other words, a precoder) in the CSI report. When the precoder or precoding matrix has rank v, the precoding matrix comprises v precoding vector(s) for v transmission layers of the precoder.

[0061] In certain embodiments, a method performed by a wireless device is proposed, the method comprising: receiving from a network node, e.g., gNB, a configuration indicating reference signals, determining based on the configuration one or more beam vectors and one or more precoding coefficients of a precoding matrix, wherein the one or more beam vectors and precoding coefficients are determined with respect to one or more parameters derived from the reference signals, generating a report indicating the precoding matrix, and reporting to the network node the report (e.g., via an uplink channel). In some embodiments, the one or more parameters derived from the reference signals are associated with one or more parameters of one or more selected components of a channel response.

[0062] In some embodiments, the method comprises selecting or determining the precoding matrix with respect to a performance metric associated with the one or more selected components of the channel response.

[0063] In some embodiments, the one or more selected components include one component, multiple components, a window or a selected range of components of the channel response. In some options, the window or range comprises or is associated with a proper subset of components of the channel response.

[0064] In some embodiments, a component of the channel response is associated with information related to at least one of a magnitude, an amplitude, a power, a delay, a time, an angle, a direction, or a Doppler-frequency.

[0065] In some embodiments, the magnitude or amplitude or power of the one or more selected components is / are smaller than the magnitude or amplitude or power of at least one other component or all other components of the channel response.

[0066] In some embodiments, the one or more selected components of the channel response are selected by the wireless device.

[0067] In some embodiments, information of the one or more selected components is reported to the network node.

[0068] In some embodiments, the one or more selected components are associated with one or more reflectors or targets in the vicinity of the wireless device.

[0069] In some embodiments, the method comprises determining the precoding matrix so that when applying the precoding matrix to the reference signals, the magnitude, amplitude, or power of at least one selected component of the channel response is reduced or increased, or reduced or increased by X dB, or above or below a certain threshold. In some embodiments, the magnitude, amplitude or power of the one or more selected components is / are larger than the magnitude, amplitude or power associated with at least one other component or all other components of the channel response.

[0070] In some embodiments, the reference signals indicated by the configuration are channel state information reference signals (CSI-RS). The configuration may indicate one or more CSI-RS resources, wherein a CSI-RS resource comprises one or more antenna or CSI-RS ports. The antenna or CSI-RS ports are used by the wireless device to determine the precoding matrix. In some embodiments, the configuration indicates a first set of reference signals associated with a first set of resources (e.g., time and / or frequency domain resources) and a second set of reference signals associated with a second set of resources (e.g., time and / or frequency domain resources), each set comprising one or more reference signals, and wherein the first set and second set of reference signals are different.

[0071] In some embodiments, the one or more reference signals from the second set of reference signals are later in time than the one or more reference signals from the first set of reference signals.

[0072] In some embodiments, the one or more reference signals from the first and second set of reference signals have common frequency domain resources and antenna ports.

[0073] In some embodiments, the channel response is determined using the one or more reference signals from the first set of reference signals.

[0074] In some embodiments, the first and second sets of reference signals are used by the wireless device for determining the one or more beam vectors and one or more precoding coefficients of the precoding matrix.

[0075] In some embodiments, the method performed by the wireless device comprises determining the precoding matrix so that when applying the precoding matrix to the second set of reference signals, a specific performance metric or criterion associated with the one or more selected components of the corresponding channel response is met or satisfied or optimized. Note that, in this option, the first set of reference signals is different to the second set of reference signals. In some options, the first set of reference signals comprises a set of CSI-RS ports. Here, a set may be associated with a single CSI-RS resource or multiple CSI-RS resources, wherein each CSI-RS resource comprises one or more antenna or CSI-RS ports. In one option, the second set of reference signals is a different set of CSI-RS ports, wherein this set is a subset of the CSI-RS ports of the same CSI-RS resource associated with the first set of reference signals, or it is a different CSI-RS resource that comprises a number of antenna or CSI-RS ports. In another option, the second set of reference signals comprises newly defined reference signals applicable for sensing in 6G communication networks. In some options, the first set of reference signals comprises reference signal(s) that is / are associated with a different slot index or slot indices than the reference signal(s) from the second set of reference signals. The slot index / indices associated with the reference signal(s) of the second set of reference signals may be in advance or future time compared to the slot index / indices associated with the reference signal(s) from the first set of reference signals.

[0076] In some options, the first set of reference signals comprises reference signal(s) that is / are associated with the same slot index as the reference signal(s) of the second set of reference signals, but the reference signal(s) from the first set of reference signals is / are associated with different frequency domain resources than the reference signal(s) from the second set of reference signals. In some options, the first set of reference signals and the second set of reference signals comprise reference signals that share the same frequency-domain resources (e.g., PRBs) and the same antenna or CSI-RS ports.

[0077] In certain embodiments, the one or more parameters derived from the reference signals are associated with one or more parameters of one or more selected components of a channel response. The channel response may comprise multiple components and is determined by the wireless device using the received reference signals indicated in the configuration. In some examples, the one or more parameters or components comprise or are associated with a magnitude, amplitude, or power and / or phase, a delay or time and / or a frequency or Doppler- frequency of the channel response. In some examples, the one or more parameters or components are represented as variables (t;), or ( / i), or tuples or (pbtj), or triplets wherein pt is a magnitude, amplitude, or power, a time or delay, and / ; a frequency or Doppler-frequency associated with a component of the channel response.

[0078] Some of the components of the channel response may be associated with reflector(s) or target(s) in the vicinity of the wireless device. A main goal of this invention disclosure is to provide a method for precoding of reference signal(s) that can be used for detecting these reflector(s) or target(s) and aims to increase the detection probability and / or accuracy of the associated components of the channel response. In some examples these targets and / or reflectors are blocking objects, humans, bicycles, or any kind of vehicles, robots, UAV, machines, drones, parts of city building elements, walls, benches, etc. This means, the wireless device may select or determine the precoding matrix such that when applying the precoding matrix to one or more reference signal(s), some selected components of the corresponding channel response can be detected by the wireless device with higher reliability and / or power, and / or amplitude and / or magnitude and / or accuracy. Optionally, some components may correspond to a certain location in the surrounding of the wireless device and / or network node.

[0079] In certain embodiments, the method performed by the wireless device may comprise selecting or determining a precoding matrix that improves the detection probability of one or more selected component(s) of the channel response. In certain embodiments, the method performed by the wireless device may comprise selecting or determining the precoding matrix with respect to a performance metric associated with the one or more selected components of the channel response. In some examples, the wireless device selects or determines the precoding matrix such that a performance metric associated with selected component(s) of the channel response is improved, increased or reduced or satisfied.

[0080] In certain embodiments, the wireless device may select or determine a precoding matrix that improves the detection probability and / or accuracy of one or more components of the channel response. In certain embodiments, the wireless device selects or determines the precoding matrix with respect to a performance metric associated with one or more selected components of the channel response. In some examples, the wireless device selects or determines the precoding matrix such that a performance metric associated with the one or more selected components of the channel response is improved, increased or reduced or satisfied.

[0081] Figure 3(a) shows an example of a channel response determined by the wireless device from the received reference signals. In this example, the channel response is a channel impulse response. There are also three selected components of the channel response, labelled as (t0, ti, t2). which are associated with three delays of the channel impulse response. The wireless device wants to detect these components with a high reliability. The wireless device therefore selects a precoding matrix that increases the component-to-noise ratio of the selected components of the channel impulse response. The wireless device reports an indication of the precoding matrix to the network node. The network node may apply the reported precoding matrix to one or more reference signals which is / are transmitted to the wireless device. The wireless device measures or estimates the components of the channel response based on the received reference signal(s). The amplitude or magnitude of the selected components is now increased compared to the other components of the channel response as shown in Figure 3(b). Hence, the wireless device can now detect these components with a high reliability.

[0082] Another example of a channel response determined by the wireless device from the received reference signals is shown in Figure 4(a). In this example, the channel response is a channel impulse response. There is a selected component of the channel response, labelled as (t0), which is associated with a single delay. The selected component is the strongest component and associated with a large or the largest magnitude or amplitude compared to the other components of the channel response. The wireless device selects a precoding matrix that reduces the magnitude or amplitude of this component such that other (selected) components of the channel response can be detected with a higher probability and / or power and / or magnitude and / or amplitude and / or accuracy. In some examples, the wireless device selects the precoding matrix that forms a null with respect to the selected (strongest) component of the channel response. The reported precoding matrix may be applied to the one or more reference signals by the network node and transmitted to the wireless device. The wireless device measures or estimates the components of the channel response based on the received reference signal(s). The amplitude or magnitude of the selected component of the channel response may now be reduced as shown in Figure 4(b). The magnitude or amplitude of the other (selected) components of the channel response may also now be increased such that the wireless device can now detect one or more of these other (selected) components (which are associated with scatterer(s) or target(s)) of the channel response with a high reliability.

[0083] In some options, a window of components comprises multiple components or multiple selected components. In some options, a window of components comprises multiple components including the strongest component of the channel response. The strongest component may be the component associated with the largest magnitude, amplitude or power compared to the other components of the channel response.

[0084] In some examples, the performance measure or metric is the component-to-noise-ratio or the component-to-noise-and-inference-ratio. Here, the component-to-noise-ratio is defined as the ratio of the magnitude, amplitude or power of one or more selected components of the channel response and the noise (e.g., the noise at the receiver of the wireless device).

[0085] In some examples, the performance measure or metric is associated with the strongest component of the channel response, wherein the strongest component is associated with the largest magnitude, amplitude or power compared to the other components of the channel response. In some examples, the performance measure or metric is associated with one or more or a set of components of the channel response.

[0086] Note that, in some examples, the component(s) of the channel response is / are selected by the wireless device or configured from a network node (e.g., by providing information of the delay- and / or Doppler-frequencies related to the components) to the wireless device. In some examples, information related to selected component(s) of the channel response (e.g., information related to the delay- and / or Doppler-frequencies related to the components) is reported to the network node.

[0087] In one example, the wireless device may select or determine the precoding matrix such that when applying the precoding matrix to the one or more reference signals, the magnitude, amplitude, or power of a strong component, or the strongest component, of the corresponding channel response is reduced, or reduced by X dB, or is above or below a certain threshold, or lower than the magnitude, amplitude, or power of a set of other components of the channel response. Here, a strong component may be the component with a large magnitude, amplitude or power compared to the other components of the channel response. The strongest component may be the component with the largest magnitude, amplitude or power compared to the magnitude, amplitude or power of the other components of the channel response.

[0088] In one example, the wireless device may select or determine the precoding matrix such that when applying the precoding matrix to the one or more reference signals, the magnitudes, amplitudes, or powers associated with a set of components of the corresponding channel response is reduced, or reduced by X dB, or is above or below a certain threshold, or lower than the magnitude, amplitude, or power of one or more other components of the channel response. In some options, the set of components may comprise multiple components. In one instance, the set may comprise the strongest component associated with time or delay and the components associated with time and delay ti+nclose or neighboring to the time or delay ttof the strongest component. This means n = -1 and / or n = +1 and / or n = -2 and / or n = 2, and so on. In some options, the set of components is selected by the wireless device or is configured to the wireless device from the network node (e.g., indirectly by indicating the time(s) or delay(s) and / or frequency(ies) or Doppler-frequency(ies) associated with the components of the channel response).

[0089] In one example, the wireless device may select or determine the precoding matrix such that when applying the precoding matrix to the reference signals, the magnitudes, amplitudes, or powers associated with one or more components of the corresponding channel response is increased, or increased by X dB, or is above or below a certain threshold, or larger than the magnitude, amplitude, or power of a set of other components of the channel response. In some options, the one or more components are selected by the wireless device and information related to these components are indicated in the report, or the information related to these components are indicated to the wireless device by the network node (e.g., by indicating the time(s) or delay(s) and / or frequency(ies) or Doppler-frequency(ies) associated with the components).

[0090] In certain embodiments, the channel response may comprise a number of components, where each component is associated with a magnitude / amplitude and / or phase and / or time or delay and / or frequency Doppler-frequency. Examples of such a channel response are as follows: a channel impulse response, or a delay profile, or power-delay profile, or a Doppler-frequency profile, or Doppler-frequency spectrum, or a delay-Doppler profile, or delay-Doppler spectrum.

[0091] In certain embodiments, a method performed by a wireless device is proposed, the method comprising:

[0092] - receiving from a network node, (e.g., a gNB), a configuration indicating reference signals,

[0093] - determining a precoding matrix based on the configuration and information related to one or more timing and / or frequency parameters and / or beam parameters,

[0094] - generating a report indicating the precoding matrix, and

[0095] - reporting to the network node the report (e.g., via an uplink channel such as PLICCH or PUSCH).

[0096] In certain embodiments, the one or more timing parameters include information related to time or delay parameters indicating one or more times or delays. The term “time” may also be referred to as a time instant or a time point, a sample or a slot. Optionally, the one or more indicated times or delays may be defined relative to a reference time or delay. Note that the one or more indicated times or delays may be defined or given by discretized or quantized values from an alphabet or a codebook. For example, the one or more timing parameters may be defined by discrete values, {to,^, ..., tN], wherein each time or delay, tj, is a value from an alphabet or codebook. Note also that the time(s) or delay(s) can be defined with respect to a reference time or delay that implies a shift of the timing parameters. For the above example, when the reference time or delay is defined by tr, the timing parameters are given by {tr+ t0, tr+ 11;..., tr+ tN}. In some options, the unit of the values or the values of the timing parameters is a function of a configured number of physical resource blocks, PRBs, or subbands, wherein a subband comprises multiple PRBs. The number of subbands (typically defined in the frequency domain) may be provided to the wireless device via a higher layer (e.g., RRC) or lower layer (e.g., DCI) configuration or indication from the network node. Note that the one or more timing parameters can be either configured to the wireless device (e.g., from the network node), or selected by the wireless device and indicated in the report, or known by the wireless device (e.g., they are defined in a specification such as the 5G NR or 6G specification).

[0097] In some options, the one or more timing parameters indicate a window or a range of times or delays. In one example, the window may be defined by a first time or delay, t0, and a second time or delay, t1;such that the window is given by [t0, t^ . In another example, the window may be defined by a first time or delay, t0, and a second time difference At0, such that the window is given by [t0, t0+ At0], Similar to above, the time(s) or delay(s) can be defined with respect to a reference time or delay that implies a shift of the timing parameters. For example, when the reference time or delay is tr, the window or range for the above two examples is given by [tr+ t0,tr+ t or [tr+ t0,tr+ 10+ At0], Note that when the time(s) or delay(s) are discrete values, the window or range may comprise a finite set of time(s) or delay(s).

[0098] In certain embodiments, the reference time or delay is a parameter (e.g., a higher layer RRC parameter) configured to the wireless device from the network node. In another option, the reference time or delay is given by the time or delay associated with a strong component or the strongest component (in terms of magnitude or amplitude or power of the components) of the channel response. In another option, the reference time or delay is selected by the wireless device, and in some examples, indicated in the report. In another option, the reference time or delay is a fixed value defined in the 5G NR or 6G specification. Note that the channel response can be determined by the wireless device using the received reference signals (e.g., CSI-RS signals). Examples of the channel response are described above.

[0099] In certain embodiments, the one or more timing parameters indicate multiple time or delay windows (or ranges), wherein, each window can be defined as explained above. In one option, the wireless device selects a window or range for determining the precoding matrix and indicates the selected window or range from the multiple time or delay windows (or ranges) in the CSI report. In another option, the wireless device is configured to receive an indication of the window or range from the network node. The multiple windows are either defined in a specification (e.g., the 5G NR or 6G specification) and hence known to the wireless device, or they are configured to the wireless device from the network node.

[0100] In certain embodiments, the one or more frequency parameters include information related to one or more frequency or Doppler-frequency parameters indicating one or more frequencies, or Doppler-frequencies. Optionally, the one or more indicated frequencies or Doppler- frequencies may be defined relative to a reference frequency or Doppler-frequency. In some options, the one or more frequency parameters indicate a window or range of frequencies, or Doppler-frequencies. Note that the frequency(ies) or Doppler-frequencies may be defined or given by discretized or quantized values from an alphabet or a codebook. For example, the one or more frequency parameters may be defined by discrete values, {f0, f1; wherein each frequency, fj, is a value from an alphabet or codebook. Note also that the frequency(ies) can be defined with respect to a reference frequency that implies a shift of the frequency parameters. For the above example, when the reference frequency is defined by fr, the one or more frequency parameters are given by {fr+ f0, fr+ f1;..., fr+ fN}. In some options, the unit of the values or the values are a function of the slot or symbol duration. Note that the one or more frequency parameters can be either configured to the wireless device (e.g., from the network node), or selected by the wireless device and indicated in the report, or known by the wireless device (e.g., they are defined in the 5G NR or 6G specification).

[0101] In some options, the one or more frequency parameters indicate a window or a range of frequencies or Doppler-frequencies. In one example, the window may be defined by a first frequency, f0, and a second frequency, f1;such that the window is given by [f0, f . In another example, the window may be defined by a first frequency, f0, and a second frequency difference Af0, such that the window is given by [f0, f0+ Af0], Note that the frequencies in the window can be defined with respect to a reference frequency that defines a frequency shift of the frequency parameter(s). For example, when the reference frequency is fr, the window is given for the above two examples by [fr+ f0, fr+ fi] or [fr+ f0, fr+ f0+ Af0] . In one option, the reference frequency is a parameter (e.g., a higher layer RRC parameter) configured to the wireless device from the network node. In another option, the reference frequency is given by the frequency associated with a strong component or the strongest component of a channel response. In another option, the value of the reference frequency is zero and known to the wireless device. The channel response can be determined by the wireless device using the received reference signals. Note that the channel response can be a Doppler-frequency profile, or a delay-Doppler spectrum or Doppler-power profile, etc. In some options, the reference frequency is determined by the wireless device (e.g., based on the channel response) and indicated in the report.

[0102] In certain embodiments, the one or more frequency parameters indicate multiple frequency windows (or ranges), wherein, in some examples, a window is defined as explained above. In one option, the wireless device selects a window or range for determining the precoding matrix and indicates the selected window or range in the report. In another option, the wireless device is configured to receive an indication of the window or range from a network node. The multiple windows are either defined in the 5G NR or 6G specification and known to the wireless device, or they are configured to the wireless device from the network node.

[0103] In certain embodiments, the wireless device is configured to determine the precoding matrix using the information related to the one or more timing and / or frequency parameters. The wireless device selects the precoding matrix that focuses or concentrates the signal energy with respect to the time(s) or delay(s) indicated by the one or more timing parameters and / or with respect to frequency(ies) or Doppler-frequency(ies) indicated by the one or more frequency parameters.

[0104] In certain embodiments, the one or more time and / or frequency parameters are defined with respect to one or more time and / or frequency parameters determined from a channel response. The channel response is determined by the wireless device from the received reference signals. In some examples, the one or more time and / or frequency parameters determined from the channel response include time or delay, frequency or Doppler-frequency associated with components of the channel response. As described above, optionally, a component of the channel response comprises or is associated with information related to at least one of a magnitude, an amplitude, a power, a phase, a delay, a time, a frequency or a Doppler-frequency. In some examples, the components can be represented as tuples tj) or triplets (Pi, t , wherein ptis a magnitude, amplitude, or power, tta time or delay, and a frequency or Doppler-frequency.

[0105] In certain embodiments, the one or more timing and / or frequency parameters are selected by the wireless device and reported to the network node, or they are configured to the wireless device from the network node.

[0106] In certain embodiments, the one or more timing and / or frequency parameters are associated with one or more parameters of a channel response. Optionally, the channel response is determined from the received reference signals.

[0107] In certain embodiments, the precoding matrix focuses or concentrates the signal energy with respect to the one or more times or delays indicated by the one or more timing parameters and / or with respect to the one or more frequencies or Doppler-frequencies indicated by the one or more frequency or Doppler-frequency parameters. In some examples, the wireless device selects the precoding matrix that focuses or concentrates the signal energy in a window or range of times or delays and / or a window of frequency(ies) or Doppler frequency(ies). Note that as mentioned above, the window or range of times or delays can be defined with respect to a reference time or delay. The reference time or delay may be associated with a strong component of the channel response. In some examples, the strong component of the channel response is the component with the largest magnitude / amplitude and / or smallest time / delay compared to the other components of the channel response. Similarly, the window or range of frequencies can be defined with respect to a reference frequency or Doppler-frequency. In some examples, the reference frequency or Doppler-frequency is associated with a strong component of the channel response (e.g., the line-of-sight component of the channel response). The one or more timing parameters and / or frequency parameters may be associated with the time / delay(s) and / or frequencies / Doppler-frequencies of the other (e.g., weaker) components of the channel response. The energy of a signal that is precoded using the selected precoding matrix is hence focused on a specific window or range (defined by the time and / or frequency parameters indicated by the configuration) of the channel response. The range or the window may include selected components of the channel response. These components may be associated with reflectors or targets in the environment of the wireless device. The network node may apply the precoder reported by the wireless device to reference signal(s) which are transmitted to the wireless device. The wireless device may then determine based on the precoded reference signal(s) the channel response. As the precoded signals focus the energy on the weaker components of the channel response, these components can now be detected by the wireless device with a higher accuracy compared to the non-precoded transmission of the reference signals. The wireless device may report the information related to the detected or estimated components (e.g., information of an amplitude, delay and / or Doppler-frequency) of the channel response to the network node or another wireless device in a report (e.g., a sensing report). In some options, the wireless device reports delay, or magnitude or power or amplitude information, or Doppler-frequency, or delay and Doppler- frequency, or amplitude / magnitude and delay, or amplitude / magnitude and Doppler-frequency, or amplitude / magnitude, delay and Doppler-frequency information associated with the components to the network node, or another wireless device. In some options, the wireless device reports reliability information associated with the detected or estimated components of the channel response to the network node. In some examples, such reliability information may be given by a value between zero and one.

[0108] In certain embodiments, the one or more beam parameters include information related to beam vectors used by the wireless device for determining the precoding matrix. This means, the one or more beam parameters indicate the beam vectors which are used for determining the precoding matrix or which cannot be used for determining the precoding matrix by the wireless device. Note that the beam vectors, as described below, can be vectors from a basis set, such as an over-sampled or non-oversampled DFT-, or IDFT-based matrix. The beam vectors are associated with the antenna ports indicated by the network node via the configuration. In some examples, the indication is a bitmap that comprises one or more parts. In one instance, the bitmap comprises at least two parts, wherein a first part indicates a set of beam vectors from the basis set, and the second part indicates amplitudes, magnitudes or power values associated with the beam vectors indicated by the first part. In some examples, the amplitude, magnitude or power associated with a beam vector is given by a value of T or ‘O’. Note that the one or more beam parameters can be either configured to the wireless device (e.g., from the network node), or selected by the wireless device and indicated in the report, or known by the wireless device (e.g., they are defined in a specification such as the 5G NR or 6G specification).

[0109] In certain embodiments, the wireless device may determine or estimate the channel response from the received reference signals and report parameters related to the channel response to the network node or another wireless device. Such parameters may include information related to the components of the channel response such as amplitude, and / or magnitude, and / or power, and / or phase and / or delay, and / or frequency, and / or Doppler-frequency. In certain embodiments, the one or more timing parameters are determined by the wireless device. For example, the one or more timing parameters are defined with respect to a reference time or timing parameter. In one example, the reference time or timing parameter is associated with a strong or the strongest component of a channel response. The one or more timing parameters may be associated with / V weaker or / V other components (i.e., other than the component associated with the reference time) of the channel response. In some examples, the magnitude or amplitude of the / V other components associated with the timing parameters are lower than a specific value of the magnitude or amplitude of the component associated with the reference time or timing parameter.

[0110] In certain embodiments, the one or more frequency parameters are determined by the wireless device. The one or more frequency parameters may be defined with respect to a reference frequency or Doppler-frequency parameter. In one example, the reference frequency or frequency parameter is associated with a strong or the strongest component of a channel response. The one or frequency parameters may be associated with / V weaker or / V other components (i.e., other than the component associated with the reference frequency) of the channel response. In some examples, the magnitude or amplitude of the / V other components associated with the frequency parameters are lower than a specific value of the magnitude or amplitude of the component associated with the reference frequency or frequency parameter.

[0111] In certain embodiments, the one or more timing parameters may comprise / V time or delay parameters, or values, and may be associated with up to / V components of the channel response. In one instance, the / V components are the / V strongest components (with respect to their magnitude or amplitude) of the channel response. In another instance, the / V components are selected by the wireless device from the channel response, wherein the / V components may include the strongest component (the component with the largest magnitude or amplitude) or not.

[0112] In certain embodiments, the one or more frequency parameters may comprise / V frequency or Doppler-frequency parameters, or values and may be associated with up to / V components of the channel response. In one instance, the / V components are the / V strongest components (with respect to their magnitude or amplitude) of the channel response. In another instance, the / V components are selected by the wireless device from the channel response, wherein the / V components may include the strongest component (the component with the largest magnitude or amplitude) or not.

[0113] The parameter / V may be fixed in the 5G NR or 6G specification or selected by the wireless device and indicated in the report or configured to the wireless device from the network node or another wireless device. In some options, the number or the maximum number of timing and / or frequency parameters is configured to the wireless device.

[0114] In certain embodiments, the precoding matrix is based on one or more beam vectors and one or more precoder coefficients.

[0115] In certain embodiments, the wireless device is configured with a higher layer configuration, wherein the configuration indicates a number of reference signals in general, or antenna or CSI-RS ports. The indicated antenna or CSI-RS ports are reference signals as well, transmitted by the network node, and used by the wireless device to determine the precoding matrix. The wireless device may be configured with 2N±N2antenna or CSI-RS ports, wherein N±and N2are integer variables. The variables N±and N2denote the number of ports or elements of an antenna port layout in a first and second dimension, respectively, which is used at the network node for data transmission and reception. The first N±N2antenna or CSI-RS ports may be associated with a first polarization and the second N±N2antenna or CSI-RS ports may be associated with a second polarization of the antenna port layout. In some examples, an antenna port layout is an antenna array comprising a set of antennas used for data transmission and / or reception at the network node, wherein one or more antennas of the antenna arrays may be associated with an antenna or CSI-RS port.

[0116] In certain embodiments, the precoding matrix may be based on one or more beam (or spacedomain, SD) vectors selected from a codebook or a beam (SD) basis set.

[0117] The precoding matrix may be defined by a linear or a nonlinear combination of L beam (SD) basis vectors selected by the wireless device from the beam (SD) basis set. Here, L is an integer, e.g., {1 ,2,4}. The beam (SD) basis set may comprise a number of beam vectors (SD vectors) or port-selection vectors as described below. Moreover, the beam vectors are combined via a number of combining coefficients.

[0118] In certain embodiments, the precoding matrix is defined across a number of subbands of a CSI reporting band. A subband may comprise a number of physical resource blocks, PRBs. The CSI reporting band may be configured to the wireless device (e.g., via the configuration as described above). In some examples, a single precoding matrix identical for all subbands may be selected by the wireless device and reported to the network node.

[0119] In certain embodiments, the precoding matrix is / are based on a linear or a nonlinear combination of one or more beam basis (or SD basis) vectors and one or more Doppler- frequency basis vectors (or time domain, TD, basis vectors). The one or more Doppler- frequency basis vectors (or TD basis vectors) are selected from a Doppler-frequency (TD) basis set. In certain embodiments, the precoding matrix is / are based on a linear or a nonlinear combination of one or more beam basis (or SD basis) vectors and one or more delay basis vectors (or frequency-domain, FD, basis vectors). The delay basis vectors (FD basis vectors) are selected from a delay (FD) basis set.

[0120] In certain embodiments, the precoding matrix is / are based on a linear or a nonlinear combination of basis vectors selected by the wireless device from beam (or SD basis), delay (FD basis) and Doppler-frequency (TD) basis sets.

[0121] This means the precoding matrix may be described by one or more beam (SD) basis vectors, and / or delay (FD) basis vectors, and / or one or more Doppler-frequency (TD) vectors, and a number of combining coefficients, wherein a combining coefficient may comprise an amplitude and a phase coefficient.

[0122] In certain embodiments, a beam (or SD) basis set may comprise multiple beam (SD) vectors. An entry of the beam (or SD) vector is associated with an antenna or CSI-RS port. In some examples, a beam vector comprises N±N2entries. In a first example, the beam basis set is a DFT- or IDFT-based matrix or an oversampled DFT- or IDFT-based matrix. In one instance, the beam basis set is an oversampled N±N2x O1N1O2N2DFT- or IDFT-based matrix. Here, and 02denote the oversampling factors with respect to a first and a second dimension, respectively, of the antenna port layout at the network node. In a second example, the beam basis set comprises a number of beam vectors which are port-selection vectors. The entries of a port-selection vector are zeros, except a single entry which is one. The beam basis set is a port-selection vector-based basis set when the antenna or CSI-RS ports are precoded by the network node. This means the network node performs beamforming / precoding of the antenna or CSI-RS signals / ports transmitted to the wireless device.

[0123] The Doppler-frequency (or TD) basis set comprises a number of Doppler-frequency or timedomain basis vectors that are related to the time units (a number of slots) of the precoding matrix. A Doppler-frequency (or TD) vector is associated with a Doppler-frequency or index and associated with a number of slots or number of slot intervals. In some examples, the time units of the precoding matrix are defined in terms of slots or slot intervals.

[0124] In one instance, a Doppler-frequency (or TD) vector may be associated with / V4time units, slots or slot intervals of the precoding matrix and an entry of the Doppler-frequency (or TD) vector may be associated with a single slot or slot interval. A slot interval comprises one or more slots. In some examples, the number of slots per slot interval is m, wherein m is an integer, e.g., m e {1,2} or m e {1,2,4}. In some examples, the Doppler-frequency (TD) basis set is an / V4x / V4DFT- or IDFT-based matrix. In another example, the Doppler-frequency (TD) basis set is an / V4x 04 / V4oversampled DFT- or IDFT-based matrix, wherein 04denotes the oversampling factor. When the Doppler-frequency (TD) vectors are DFT- or IDFT-based vectors, a Doppler-frequency (TD) vector may be associated with a discrete frequency or Doppler-frequency (index) value. Hence, the basis set may be associated with N4or 04N4frequency or Doppler-frequency (index) values.

[0125] The delay basis set (or FD basis set) comprises a number of delay (FD) vectors associated with the frequency units of the precoding matrix. A delay (FD) vector is associated with a number of physical resource blocks, PRBs, subbands or subcarriers. In some examples, the precoding matrix or the delay (FD) vectors of the precoding matrix are associated with N3subbands, wherein a subband comprises a number of PRBs. In some examples, the delay (FD) basis set is an N3x N3DFT- or IDFT-based matrix. In another example, the delay (FD) basis set is an N3x O3N3oversampled DFT- or IDFT-based matrix, wherein 03denotes the oversampling factor. When the delay (FD) vectors from the delay (FD) basis set are DFT- or IDFT-based vectors, a delay (FD) vector may be associated with a discrete time or delay (index) value. Hence, the delay (FD) basis set may be associated with N3or O3N3time or delay (index) values.

[0126] In some examples, the precoding matrix is based on a selection of L beam vectors from the beam basis set, M delay (FD) vectors from the delay (FD) basis set and a number of combining coefficients for combining the L beam and M delay vectors.

[0127] In some examples, the precoding matrix is based on a selection of L beam vectors from the beam basis set, Q Doppler-frequency (TD) vectors from the Doppler-frequency (TD) basis set and a number of combining coefficients for combining the L beam and Q Doppler-frequency vectors.

[0128] In some examples, the precoding matrix is based on a selection of L beam vectors from the beam basis set, M delay (FD) vectors from the delay (FD) basis set, and Q Doppler-frequency (TD) vectors from the Doppler-frequency (TD) basis set, and a number of combining coefficients for combining the L beam, M delay vectors, and Q Doppler-frequency (TD) vectors.

[0129] In certain embodiments, the precoding matrix is based on a plurality of beam (SD) vectors and delay (FD) vectors, and a number of combining coefficients for combining the beam (SD) vectors and delay (FD) vectors. The beam (SD) vectors may be associated with multiple port groups, wherein a port group is associated with several reference signals or comprises several antenna ports. A port group may be associated with a transmission reception point, TRP, or a network node. The wireless device may be configured with N < N' port groups, where N’ may be a total number of port groups, and N may be a configured or selected number of port groups. In some examples, a port group is identical to a resource, e.g., a CSI-RS resource, that comprises several antenna ports. In some examples, the wireless device is configured to select Lnbeam (or SD) vectors for the n-th port group (n = 0, ... , N - 1) and a number of combining coefficients for combining the selectednLnbeam vectors across the N port groups. The wireless device may be configured with N' port groups. In some examples, the wireless device may select N port groups out of the configured N' port groups. In some examples, N = N'. In some examples, the wireless device is configured to select Lnbeam (or SD) vectors for the n- th port group (n = 0, ... , N - 1), one delay (FD) vector for the n-th port group and a number of combining coefficients for combining the selectednLnbeam vectors and delay vectors across the N port groups. Here, it is assumed that a delay vector is associated with a port group. The wireless device selects the beam and delay vectors in such a way that when applying the precoding matrix to a reference or data signal, the amplitude or magnitude or power of the dominant or strong component(s) of the corresponding channel response is reduced, or the magnitude or power associated with a set of components of the corresponding channel response is increased. Here, it is assumed that one or more components from the set of components are associated with target(s) in the vicinity of the wireless device. The vicinity of the wireless device may be based on a pre-defined distance or a pre-defined threshold value. The wireless device wants to detect the target(s) by estimating parameters (e.g., magnitude, delay and Doppler-frequency) associated with the one or more components from the set of components of the channel response. In certain embodiments, one of the port groups is a reference port group. For the reference port group, the index of the associated delay vector is zero. Assuming that the delay vectors are DFT- or IDFT-based vectors, the delay vector associated with the reference port group is given by the all-one vector.

[0130] In certain embodiments, a method performed by a wireless device (e.g., a User Equipment, UE)(300) is disclosed. The method comprises:

[0131] - receiving from a network node, (e.g., a gNB), a configuration indicating a number of reference signals, or antenna ports,

[0132] - determining based on the configuration a first and a second precoding matrix, and selecting one or more beam vectors, wherein each precoding matrix is based on the one or more selected beam vectors and precoding coefficients, and wherein one of more beam vectors of the first precoding matrix are identical to one or more beam vectors of the second precoding matrix,

[0133] - generating a report indicating at least the one or more selected beam vectors associated with the first and second precoding matrices, and

[0134] - reporting, to the network node the report (e.g., via an uplink channel).

[0135] In certain embodiments, the beam vectors of the first precoding matrix are identical to the beam vectors of the second precoding matrix for one or more layers. In some examples, the second precoding matrix comprises only a single vector and the first precoding matrix may comprise a single vector or multiple vectors.

[0136] In certain embodiments, the first precoding matrix is selected by the wireless device with respect to a certain performance metric such as the signal-to-noise-ratio, SNR, signal-to-noise- and-inference-ratio, SI NR, block-error-rate, BLER, or any other metric. This means, the wireless device selects the basis vectors related to the different basis sets of the precoding matrix, as described above, in such a way that a performance metric is optimized or achieved. For example, the wireless device may select the first precoder together with a channel quality indicator index, CQI, indicating a modulation and coding scheme, MCS, such that a certain block error rate of a transmission applying the precoding matrix by the network node is achievable.

[0137] In certain embodiments, the wireless device selects one or more components of the channel response and the second precoding matrix that improves the detection probability of the selected components of the channel response or with respect to a certain performance measure or metric associated with the selected components of the channel response. The second precoding matrix may be selected by the wireless device such that when applying the second precoding matrix at the network node, the energy of the precoded transmit signal(s) is / are directed to the non-dominant components of the wireless channel between the network node and the wireless device. The corresponding beam pattern of the antenna port layout at the network node may have null(s) towards the dominant direction(s) of the wireless channel. In some examples, a dominant direction is the direction of the line-of-sight, LOS, component of the wireless channel. Hence, when the network node uses the information of the second precoding matrix indicated in the CSI report to precode the antenna or CSI-RS ports, a wireless device, that is configured to measure the CSI-RS signals, is able to estimate or to detect the non-dominant components of the wireless channel.

[0138] The wireless device is configured to report information related to the measured CSI-RS in a CSI-report to the network node. The CSI report may contain information related to the detected components of the wireless channel. Examples of such information include delay (frequencydomain) and Doppler-frequency (time-domain) information related to the channel response.

[0139] In certain embodiments, the beam vectors of the first precoding matrix are identical to the beam vectors of the second precoding matrix for one or more layers of the first precoding matrix. In some examples, the beam vectors of the first precoding matrix can be different for at least two layers of the precoding matrix and may depend on the layer index of the precoding matrix. For example, the beam vectors of the first precoder are different for at least two layers of the precoding matrix, and the beam vectors of the first precoding matrix of the first layer are identical to the beam vectors of the second precoding matrix. In certain embodiments, the CSI report contains information about the selected one or more beam vectors for each precoding matrix.

[0140] Referring to Figure 5, there is illustrated a method (500) performed by a wireless device (300) according to some of the previously described embodiments. The method is performed by the wireless device (300) in a wireless communication system, which may also be referred to as a wireless communications network. The method comprises: receiving (501) from a network node, a configuration indicating reference signals, determining (502) based on the configuration one or more beam vectors and one or more precoding coefficients of a precoding matrix, wherein the one or more beam vectors and precoding coefficients are determined with respect to one or more parameters derived from the reference signals , generating (503) a report indicating the precoding matrix, and

[0141] - reporting (504) to the network node the report (e.g., via an uplink channel such as PUCCH or PUSCH).

[0142] In certain embodiments, there is provided another method performed by a wireless device in a wireless communication system. The method comprises: receiving from a network node a configuration indicating reference signals, determining a precoding matrix based on the configuration and information related to one or more timing and / or frequency parameters and / or beam parameters, generating a report indicating the precoding matrix, and reporting to the network node the report (e.g., via an uplink channel such as PUCCH or PUSCH).

[0143] In certain embodiments, there is provided another method performed by a wireless device in a wireless communication system. The method comprises:

[0144] - receiving from a network node, a configuration indicating a number of reference signals, or antenna ports,

[0145] - determining based on the configuration a first and a second precoding matrix, and selecting one or more beam vectors, wherein each precoding matrix is based on the one or more selected beam vectors and precoding coefficients, and wherein one of more beam vectors of the first precoding matrix are identical to one or more beam vectors of the second precoding matrix,

[0146] - generating a report indicating at least the one or more selected beam vectors associated with the first and second precoding matrices, and - reporting to the network node the report.

[0147] In order to perform the previously described process or method steps performed by the wireless device (e.g., a UE or an loT device), there is also provided a wireless device. Figure 7 illustrates a simplified block diagram depicting a wireless device (e.g., a UE or an loT device) 300. The wireless device 300 may comprise a processor 310 or processing circuit or a processing module or a processor means 310; a receiver circuit or receiver module 340; a transmitter circuit or transmitter module 350; a memory module 320, a transceiver circuit or transceiver module 330 which may include the transmitter circuit 350 and the receiver circuit 340. The wireless device 300 further comprises an antenna system 360 which includes antenna circuitry for transmitting and receiving signals to / from at least the network node or other wireless device(s). The antenna system employs beamforming as previously described.

[0148] The wireless device 300 may belong to any radio access technology including 4G or LTE, LTE- A, 5G, advanced 5G, 6G, or a combination thereof that support beamforming technology. The wireless device 300 may be a UE or an loT device. The wireless device comprising the processor and the memory contains instructions executable by the processor, whereby the wireless device 300 is operative or is configured to perform any one of the embodiments related to the wireless device as previously described.

[0149] The processing module / circuit 310 includes a processor, microprocessor, an application specific integrated circuit (ASIC), field programmable gate array (FPGA), or the like, and may be referred to as the “processor.” The processor 310 controls the operation of the wireless device and its components. Memory (circuit or module) 320 includes a random-access memory (RAM), a read only memory (ROM), and / or another type of memory to store data and instructions that may be used by processor 310. In general, it will be understood that the wireless device 300 in one or more embodiments includes fixed or programmed circuitry that is configured to carry out the operations in any of the embodiments disclosed herein.

[0150] In at least one such example, the processor 310 includes a microprocessor, microcontroller, DSP, ASIC, FPGA, or other processing circuitry that is configured to execute computer program instructions from a computer program stored in a non-transitory computer-readable medium that is in or is accessible to the processing circuitry. Here, “non-transitory” does not necessarily mean permanent or unchanging storage, and may include storage in working or volatile memory, but the term does connote storage of at least some persistence. The execution of the program instructions specially adapts or configures the processing circuitry to carry out the operations disclosed in this disclosure relating to the wireless device. Further, it will be appreciated that the wireless device 300 may comprise additional components. The wireless device 300 by means of processor 310 executes instructions contained in the memory 320 whereby the wireless device is operative to perform any one of the previously described embodiments related to the actions performed by the wireless device, some of which are presented in appended claims.

[0151] There is also provided a computer program comprising instructions which when executed by the processor 310 of the wireless device 300 cause the processor 310 to carry out the method according to any one of the previously described embodiments.

[0152] There is also provided a computer program comprising instructions which when executed by the processor 310 of the wireless device 300 cause the processor 310 to carry out the method according to some embodiments as described herein.

[0153] Referring to Figure 6, there is illustrated a method (600) performed by a network node (400) in a wireless communication system according to some of the previously described embodiments. The method comprises: transmitting (601) to a wireless device a configuration indicating reference signals, for enabling the wireless device to: determine based on the configuration one or more beam vectors and one or more precoding coefficients of a precoding matrix, wherein the one or more beam vectors and precoding coefficients are determined with respect to one or more parameters derived from the reference signals, generate a report indicating the precoding matrix, and

[0154] - receiving (602) the report from the wireless device (e.g., via an uplink channel).

[0155] In certain embodiments, another method performed by a network node (400) in a wireless communication system is proposed. The method comprises: transmitting to a wireless device a configuration indicating reference signals, for enabling the wireless device to: determine a precoding matrix based on the configuration and information related to one or more timing and / or frequency parameters and / or beam parameters, generate a report indicating the precoding matrix, and receiving the report from the wireless device (e.g., via an uplink channel). In certain embodiments, another method performed by a network node (400) in a wireless communication system is proposed. The method comprises: transmitting to a wireless device, a configuration indicating a number of reference signals, or antenna ports, for enabling the wireless device to:

[0156] - determine based on the configuration a first and a second precoding matrix, and select one or more beam vectors, wherein each precoding matrix is based on the one or more selected beam vectors and precoding coefficients, and wherein one of more beam vectors of the first precoding matrix are identical to one or more beam vectors of the second precoding matrix,

[0157] - generate a report indicating at least the one or more selected beam vectors associated with the first and second precoding matrices, and receiving the report from the wireless device.

[0158] In order to perform the previously described process or method steps performed by the network node there is also provided a network node. Figure 8 illustrates a block diagram depicting a network node 400. The network node 400 may comprise a processor 410 or processing circuit or a processing module or a processor means 410; a receiver circuit or receiver module 440; a transmitter circuit or transmitter module 450; a memory module 420. The network node 400 may also comprise a transceiver circuit or transceiver module 430 which may include the transmitter circuit 450 and the receiver circuit 440. The network node 400 further comprises an antenna system 460 which includes antenna circuitry for transmitting and receiving signals to / from at least the wireless device. The antenna system employs beamforming as previously described.

[0159] The network node 400 may belong to any radio access technology including 4G or LTE, LTE- A, 5G, advanced 5G or a combination thereof that support beamforming technology. The network node may be a gNB. The network device comprising the processor and the memory contains instructions executable by the processor, whereby the network node 400 is operative or is configured to perform any one of the embodiments related to the network node 400 as previously described.

[0160] The processing module / circuit 410 includes a processor, microprocessor, an application specific integrated circuit (ASIC), field programmable gate array (FPGA), or the like, and may be referred to as the “processor.” The processor 410 controls the operation of the network node and its components. Memory (circuit or module) 420 includes a random-access memory (RAM), a read only memory (ROM), and / or another type of memory to store data and instructions that may be used by processor 410. In general, it will be understood that the network node in one or more embodiments includes fixed or programmed circuitry that is configured to carry out the operations in any of the embodiments disclosed herein.

[0161] In at least one such example, the processor 410 includes a microprocessor, microcontroller, DSP, ASIC, FPGA, or other processing circuitry that is configured to execute computer program instructions from a computer program stored in a non-transitory computer-readable medium that is in or is accessible to the processing circuitry. Here, “non-transitory” does not necessarily mean permanent or unchanging storage, and may include storage in working or volatile memory, but the term does connote storage of at least some persistence. The execution of the program instructions specially adapts or configures the processing circuitry to carry out the operations disclosed in this disclosure relating to the network node. Further, it will be appreciated that the network node 400 may comprise additional components. The network node 400 may also be viewed as a Transmitter and Receiver Point (TRP).

[0162] The network node 400 by means of processor 410 executes instructions contained in the memory 420 whereby the network node 400 is operative to perform any one of the previously described embodiments related to the actions performed by the network node.

[0163] There is also provided a computer program comprising instructions which when executed by the processor 410 of the network node cause the processor 410 to carry out the method according to some embodiments described herein.

[0164] Reference throughout this specification to “an example” or “exemplary” means that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment of the present technology. Thus, appearances of the phrases “in an example” or the word “exemplary” in various places throughout this specification are not necessarily all referring to the same embodiment.

[0165] Throughout this disclosure, the word "comprise" or “comprising” has been used in a nonlimiting sense, i.e. meaning "consist at least of". Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. The embodiments herein may be applied in any wireless systems including LTE or 4G, LTE-A (or LTE-Advanced), 5G, advanced 5G, 6G, WiMAX, WiFi, satellite communications, TV broadcasting, etc.

Claims

CLAIMS1 . A method performed by a wireless device in a wireless communication system, the method comprising: receiving from a network node, a configuration indicating reference signals, determining based on the configuration one or more beam vectors and one or more precoding coefficients of a precoding matrix, wherein the one or more beam vectors and precoding coefficients are determined with respect to one or more parameters derived from the reference signals, generating a report indicating the precoding matrix, and reporting to the network node the report.

2. The method of claim 1 , wherein the one or more parameters derived from the reference signals are associated with one or more parameters of one or more selected components of a channel response.

3. The method of claim 2, wherein the method comprising selecting or determining the precoding matrix with respect to a performance metric associated with the one or more selected components of the channel response.

4. The method of claim 2 or 3, wherein the one or more selected components include one component, multiple components, a window or a selected range of components of the channel response.

5. The method of claim 2, wherein a component of the channel response is associated with information related to at least one of a magnitude, an amplitude, a power, a delay, a phase, a time, a frequency or a Doppler-frequency.

6. The method of claim 5, wherein the magnitude or amplitude or power of the one or more selected components is / are smaller than the magnitude or amplitude or power of at least one other component or all other components of the channel response.

7. The method of claim 3, wherein the performance metric is a component-to-noise-ratio defined as a ratio of the magnitude, amplitude or power of the one or more selected components of the channel response and the noise.

8. The method of claim 2, wherein the one or more selected components of the channel response are selected by the wireless device.

9. The method of claim 5, wherein information of the one or more selected components is reported to the network node.

10. The method of claim 2, wherein the one or more selected components are associated with one or more reflectors or targets in the vicinity of the wireless device.

11. The method of claim 5, wherein the method comprising determining the precoding matrix so that when applying the precoding matrix to the reference signals, the magnitude, amplitude, or power of at least one selected component of the channel response is reduced or increased, or reduced or increased by X dB, or above or below a certain threshold.

12. The method of claim 5, wherein the magnitude, amplitude or power of the one or more selected components is / are larger than the magnitude, amplitude or power associated with at least one other component or all other components of the channel response.

13. The method of claim 1 , wherein the configuration indicates a first set of reference signals associated with a first set of resources and a second set of reference signals associated with a second set of resources, each set comprising one or more reference signals, and wherein the first set and second set of reference signals are different.

14. The method of claim 13, wherein the one or more reference signals from the second set of reference signals are later in time than the one or more reference signals from the first set of reference signals.

15. The method of claim 13, wherein the one or more reference signals from the first and second set of reference signals have common frequency domain resources and antenna ports.

16. The method of claims 2 and 13, wherein the channel response is determined using the one or more reference signals from the first set of reference signals.

17. The method of claims 2 and 13, wherein the method comprising determining the precoding matrix so that when applying the precoding matrix to the second set of reference signals, a performance metric associated with the one or more selected components of the corresponding channel response is satisfied or optimized.3618. The method of claim 2, wherein the channel response is a channel impulse response, or a delay profile, or a power-delay profile, or a Doppler-frequency profile, or a Doppler- frequency spectrum, or a delay-Doppler profile, or a delay-Doppler spectrum.

19. A method performed by a wireless device in a wireless communication system, the method comprising: receiving from a network node, a configuration indicating reference signals, determining a precoding matrix based on the configuration and information related to one or more timing and / or frequency parameters and / or beam parameters, generating a report indicating the precoding matrix, and reporting to the network node the report.

20. The method of claim 19, wherein the one or more timing parameters include information related to time or delay parameters indicating one or more times or delays.

21. The method of claim 20, wherein the one or more indicated times or delays are defined relative to a reference time or delay.

22. The method of claim 20, wherein the one or more timing parameters indicate a window or a range of times or delays.

23. The method of claim 19, wherein the one or more frequency parameters include information related to one or more frequency or Doppler-frequency parameters indicating one or more frequencies, or Doppler-frequencies.

24. The method of claim 23, wherein the one or more indicated frequencies or Doppler- frequencies are defined relative to a reference frequency or Doppler-frequency.

25. The method of claim 23 or 24, wherein the one or more frequency parameters indicate a window or a range of frequencies or Doppler-frequencies.

26. The method of claim 19, wherein the one or more timing and / or frequency parameters are selected by the wireless device and reported to the network node, or they are configured to the wireless device from the network node.

27. The method of claim 19, wherein the one or more timing and / or frequency parameters are associated with one or more parameters of a channel response.

28. The method of claim 27, wherein the channel response is determined from the received reference signals.

29. The method of claim 20 or 23, wherein the precoding matrix focuses or concentrates the signal energy with respect to the one or more times or delays indicated by the one or more timing parameters and / or with respect to the one or more frequencies or Doppler- frequencies indicated by the one or more frequency or Doppler-frequency parameters.

30. A wireless device (300) comprising a processor (310) and a memory (320) containing instructions executable by said processor (310), whereby the wireless device (300) is operative to perform the method according to any of claims 1-29.

31. A method performed by a network node in a wireless communication system, the method comprising: transmitting to a wireless device a configuration indicating reference signals, for enabling the wireless device to: determine based on the configuration one or more beam vectors and one or more precoding coefficients of a precoding matrix, wherein the one or more beam vectors and precoding coefficients are determined with respect to one or more parameters derived from the reference signals, generate a report indicating the precoding matrix, and- receiving the report from the wireless device.

32. A network node (400) comprising a processor (410) and a memory (420) containing instructions executable by said processor (410), whereby the network node (400) is operative to perform the method according to claim 31.

33. The network node of claim 32, wherein the network node is a gNB.

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