Method and apparatus for CSI reporting in a wireless communications network

Abstract

The embodiments of the present invention relate to methods and apparatuses, in the form of a wireless device (700), and a network node (800). The method performed by the wireless device comprises receiving (301) from a network node a higher layer configuration comprising an indication of a number of oversampling groups, wherein each indicated oversampling group indicates maximum allowable amplitude values for a proper subset of beam vectors from a set of beam vectors for restricting an amplitude associated with a beam vector. The method further comprises calculating (302) a precoding matrix. The precoding matrix is based on at least one beam vector from the set of beam vectors. The method further comprises generating (303) a CSI report comprising a Precoder Matrix Indicator, PMI, indicating the precoding matrix. The method further comprises reporting (304) the CSI report to the network node.

Description

[0001]METHOD AND APPARATUS FOR CSI REPORTING IN A WIRELESS COMMUNICATIONS NETWORK TECHNICAL FIELD The present disclosure relates to the field of wireless communications, and in particular to methods and apparatuses for CSI reporting in a wireless communications network such as advanced 5G or 6G networks. BACKGROUND The radio access technology (RAT) in fifth generation (5G) mobile communications system, also known as 5G new radio (NR), provides a higher level of performance and flexibility than the previous generations of mobile communications systems.5G mobile communications has been driven by the need to provide ubiquitous connectivity for applications as diverse automotive communications, remote control with feedback, video downloads, as well as data applications for Internet-of-Things (IoT) devices, machine type communication (MTC) devices, etc. 5G wireless technology brings several main benefits, such as faster speed, shorter delays and increased connectivity. 5G mobile communications supports massive multiple-input multiple-output antenna technologies from sub-6 GHz up to mmWave-frequencies, new beamforming management procedures to provide increased beamforming gain and link reliability, new waveforms, etc. The third-generation partnership project (3GPP) provides the complete system specification for the 5G network architecture, which includes at least a radio access network (RAN), core transport networks (CN) and service capabilities. Due to the amount of traffic that needs to be handled by the network is growing significantly, there exists a need to utilize the downlink resources efficiently. SUMMARY Until 3GPP NR phase 4 (Rel.18), only 32 antenna port based single-TRP transmission has been supported by the specification. However, for 3GPP NR phase 5 (Rel.19), it has been decided to specify support for single-TRP transmission for up to 128 antenna ports. To realize large number of antenna ports, the dimension of the antenna portlayout in a first dimension, ^^, and a second dimension, ^^, need to be increased. In one option, the first dimension may correspond to a column dimension and the second dimension may correspond to a row dimension of the antenna port layout. In another option, the first dimension may correspond to a row dimension and the second dimension may correspond to a column dimension of the antenna port layout. The antenna port layout may be associated with a number of rows and columns, wherein each entry (row index, column index) is associated with one antenna port or twoantenna ports (e.g., in case of a dual-polarized antenna port layout). When the valuesof ^^ and ^^ (i.e., the number of antenna ports) are increased, the overheadassociated with the Radio Resource Control (RRC) configuration information elementn1-n2-codebookSubsetRestriction increases drastically. This becomes notablebecause a second bit sequence ^^ (used for the indication of the maximum allowedamplitude values or coefficients for the beam vectors associated with the precodermatrix) as a part of the information element n1-n2-codebookSubsetRestriction scalesproportionally with increasing values of ^^and ^^.This invention focuses on solutionsrelated to the overhead reduction of the RRC signaling from the network node to thewireless device. It is an objective of the embodiments herein to provide methods and apparatuses for configuration overhead reduction in a wireless communications network such as advanced 5G networks. According to an aspect of some embodiments herein, there is provided a methodperformed by a wireless device (e.g., a UE) in a wireless communications network, themethod comprising: ^receiving from a network node a higher layer configuration comprising anindication of a number of oversampling groups, wherein each indicated oversampling group indicates maximum allowable amplitude values for a proper subset of beam vectors from a set of ^^^^ beam vectors forrestricting an amplitude associated with a beam vector; ^calculating a precoding matrix, the precoding matrix being based on at leastone beam vector from the set of ^^^^ beam vectors;^ generating a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^reporting the CSI report to the network node.According to an aspect of some embodiments herein, there is provided a methodperformed by a wireless device (e.g., a UE) in a wireless communications network, themethod comprising: ^receiving from a network node a higher layer configuration comprising anindication of a number of oversampling groups, wherein each indicated oversampling group indicates a number of maximum allowable amplitude values, X, and a number of beam groups, Y, wherein a beam group comprises a set of beam vectors, and wherein a maximum allowableamplitude value is used for restricting an amplitude associated with a beam vector; ^calculating a precoding matrix, the precoding matrix being based on at leastone beam vector from the set of ^^^^ beam vectors;^ generating a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^reporting the CSI report to the network node.According to another aspect of some embodiments herein, there is provided a methodperformed by a network node (e.g., a gNB), and the method comprising:^ transmitting to a wireless device a configuration comprising an indication ofa number of oversampling groups, wherein each indicated oversampling group indicates maximum allowable amplitude values for a proper subset of beam vectors from a set of ^^^^beam vectors for restricting an amplitude associated with a beam vector; for enabling the wireless device to: ocalculate a precoding matrix, the precoding matrix being based on atleast one beam vector from the set of ^^^^ beam vectors;o generate a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^receiving from the wireless device a CSI report.According to another aspect of some embodiments herein, there is provided a methodperformed by a network node (e.g., a gNB), and the method comprising:^ transmitting to a wireless device a configuration comprising an indication ofa number of oversampling groups, wherein each indicated oversamplinggroup indicates a number of maximum allowable amplitude values, X, and a number of beam groups, Y, wherein a beam group comprises a set of beam vectors, ^and wherein a maximum allowable amplitude value is used for restricting anamplitude associated with a beam vector; for enabling the wireless deviceto: ocalculate precoding matrix, the precoding matrix being based on atleast one beam vector from the set of ^^^^ beam vectors;o generate a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^receiving from the wireless device a CSI report.According to another 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 said wireless device is operative or configured to perform any one of the embodiments presented in the detailed description relatedto the actions performed by the wireless device.According to yet another 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. 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 said one processor to carry out the actions or method steps presented herein. 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 said one processor to carry out the method steps presented herein. 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.In this invention, several solutions related to the overhead reduction of the RRCconfiguration related to codebook subset restriction are proposed. Additional advantages of the embodiments herein are provided in the detailed description of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention are now described in further detail with reference to the accompanying drawings, in which:Fig. 1 shows a schematic representation of a wireless communications system;Fig. 2 shows a block-based model of a MIMO DL transmission using codebook-based-precoding in accordance with LTE Release 8;Fig. 3 illustrates a flowchart of a method performed by a wireless device (e.g., aUE) according to some embodiments herein;Fig. 4 illustrates a flowchart of a method performed by a wireless device (e.g., aUE) according to some embodiments herein;Fig. 5 illustrates a flowchart of a method performed by a network node (e.g., agNB) according to some embodiments herein;Fig. 6 illustrates a flowchart of a method performed by a network node (e.g., agNB) according to some embodiments herein;Fig. 7 is a block diagram depicting a wireless device (e.g., a UE) according toexemplary embodiments herein;Fig. 8 is a block diagram depicting a network node (e.g., a gNB) according toexemplary embodiments herein. DETAILED DESCRIPTION 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. 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 orradio base stations, which in 5G are called gNBs. Three radio base stations aredepicted 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. A user or a user equipment (UE) may be a wireless or a mobile terminal device or a stationary communication device. A mobile terminal device or a UE may also be an IoT device, an MTC device, etc. IoT devices may include wireless sensors, software, actuators, and computer devices. They can be imbedded into mobile devices, motor vehicle, industrial equipment, environmental sensors, medical devices, aerial vehicles and more, as well as network connectivity that enables these devices to collect and exchange data across an existing network infrastructure. Referring back to Figure 1, each cell is shown including UEs and IoT devices. gNB1 in cell 121 serves UE1121A, UE2121B and IoT device 121C. Similarly, gNB2 in cell 121 serves UE3122A, UE4122B and IoT device 122C, and gNB3 in cell 123 serves UE5 123A, UE6123B and IoT device 123C. The network 100 may include any number of UEs and IoT 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 station gNB1 to gNB3 may be connected to the CN 120, e.g., via the S1 interface, via respective backhaul links 111, 121D, 122D, 123D,which are schematically depicted in Fig. 1 by the arrows pointing to “core”. The corenetwork 120 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 121E, 122E and 123E, which is depicted in the figure by the arrows pointing to gNBs. 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 fewOFDM symbols. Slot aggregation is supported in 5G NR, and hence data transmission can be scheduled to span over one or multiple slots. Slot format indication informs a wireless device or UE whether an OFDM symbol is downlink, uplink or flexible. In some examples, the wireless communication network system 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 (UFMC), 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. The wireless communications network system 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 or the 5G or NR, standard. In the wireless communications network system such as the one depictedschematically in Figure 1, multi-antenna techniques may be used, e.g., in accordancewith 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 precoder 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 precoder 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), downlink signals convey data signals, control signals containing downlink, DL, control information (DCI), and a number of reference signals or symbols (RS) used for different purposes. A gNodeB (or gNB or base station) transmits data and downlink control information (DCI) through the so-called physical downlink shared channel (PDSCH) and physical downlink control channel (PDCCH) or enhanced PDCCH (ePDCCH), respectively. Moreover, the downlink signal(s) of the gNB may contain one or multiple types of reference signals (RSs) including a common RS (CRS) in LTE, a channel state information RS (CSI-RS), a demodulation RS (DM-RS), and a phase tracking RS (PT-RS). The CRS is transmitted over a DL system bandwidth part and used at the user equipment (UE) to obtain a channel estimate to demodulate the data or control information. The CSI-RS is transmitted with a reduced density in the time and frequency domain compared to CRS and used at the UE for channel estimation or for channel state information (CSI) acquisition. The DM-RS is transmitted only in a bandwidth part of the respective PDSCH and used by the UE for data demodulation. For signal precoding at the gNB, several CSI-RS reporting mechanisms are used such as non-precoded CSI-RS and beamformed CSI-RS reporting. For a non-precoded CSI-RS, a one-to-one mapping between a CSI-RS port and a transceiver unit, TXRU, 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-UE-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. In a wireless communications network system employing time division duplexing, TDD, due to channel reciprocity, the CSI is available at the base station (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 gNB.Figure 2 shows a block-based model of a Multiple Input Multiple Output (MIMO) DLtransmission using codebook-based-precoding in accordance with LTE release 8.Fig. 2 shows schematically the base station 200, gNB, the user equipment, UE, 202and 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 matrix F from a codebook 210. 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 ANTRhaving 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 15 support the use ofseveral downlink reference symbols (such as CSI-RS) for CSI estimation at the UE.In FDD systems (up to Rel.15), 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 (RI), 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 RI are used to determine the precoding matrix from apredefined set of matrices Ω also referred to as codebook. The codebook, e.g., inaccordance with LTE, may be a look-up table with matrices in each entry of the table, and the PMI and RI from the UE decide from which row and column of the table the precoder matrix to be used is obtained. The precoders and codebooks are designed up to Rel.15 for gNBs equipped with one-dimensional Uniform Linear Arrays (ULAs)having ^^ dual-polarized antennas (in total ^^ = 2^^ antennas or antenna ports), orwith two-dimensional Uniform Planar Arrays (UPAs) having dual-polarized antennasat ^^^^ positions (in total ^^ = 2^^^^ antennas or antenna ports). The ULA allowscontrolling 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 precoder matrix are obtained from the codebook, and the PMI and the RI are used to read the codebook and obtain the precoder. The array steeringvectors may be described by the columns of a two-dimensional Discrete FourierTransform (DFT) matrix when ULAs or UPAs are used for signal transmission. The precoder matrices used in the Type-I, Type-I multi-panel and Type-II CSI reporting schemes in 3GPP NR standards are defined by a dual-stage structure (i.e., twocomponents codebook), ^ = ^^^^. The first component or the so-called first stageprecoder or matrix, ^^, is used to select a number of beam vectors from a Discrete Fourier Transform-based (DFT-based) matrix, which is also called the spatialcodebook. Moreover, the first stage precoder, ^^, corresponds to a wide-band matrixand 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, ^^, corresponds to a selection / combining / co-phasing matrix to select / combine / co-phase the beams defined in ^^. For rank-^ transmission, ^ contains ^ vectors, wherein^ denotes the transmission rank, where the entries of each vector are chosen tocombine single or multiple beams within each polarization. The selection of the matrices ^^and ^^is performed by the UE based on reference signals such as CSI- RS and the knowledge of the channel conditions. The selected matrices are indicatedin a CSI report in the form of a RI (the RI is the rank indicator and denotes the rank ofthe precoding matrix) and a PMI and are used at the gNB to update the multi-user precoder for the next transmission time interval. 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. The term serving cell and carrier component (CC) 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 ofa component carrier / serving cell, the size of the cell and the beamformed referencesignals may vary. The term ‘PDxCH’ or ‘PDXCH’ may indicate either the physical downlink shared channel (PDSCH) or the physical downlink control channel (PDCCH), while ‘PUxCH’ or ‘PUXCH’ may indicate either the physical uplink shared channel (PUSCH) 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. 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.In certain embodiments, the wireless device receives from a network node (e.g., gNB),a higher layer configuration indicating a number of antenna ports or CSI-RS ports, anda number of CSI-RS resources, wherein each CSI-RS resources comprises at leastone antenna or CSI-RS port, and determines based on the higher layer configurationa precoder matrix for the number of antenna ports or CSI-RS ports of the CSI-RSresources. The wireless device generates a CSI report comprising a Precoder MatrixIndicator (PMI) and / or information related to the PMI, indicating the precoder matrixfor the number of antenna or CSI-RS ports, and transmits over an uplink channel thegenerated CSI report to the network node. In certain embodiments, a method performed by a wireless device in a wireless communications network is proposed, the method comprising:^ receiving from a network node a higher layer configuration comprising anindication of a number of oversampling groups, wherein each indicated oversampling group indicates maximum allowable amplitude values for a proper subset of beam vectors from a set of ^^^^ beam vectors forrestricting an amplitude associated with a beam vector; ^calculating a precoding matrix, the precoding matrix being based on at leastone beam vector from the set of ^^^^ beam vectors;^ generating a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^reporting the CSI report to the network node.In certain embodiments, a method performed by a wireless device in a wireless communications network is proposed, the method comprising: ^receiving from a network node a higher layer configuration comprising anindication of a number of oversampling groups, wherein each indicated oversampling group indicates a number of maximum allowable amplitude values, X, and a number of beam groups, Y, wherein a beam group comprises a set of beam vectors, and wherein a maximum allowable amplitude value is used for restricting an amplitude associated with a beam vector; ^calculating a precoding matrix, the precoding matrix being based on at leastone beam vector from the set of ^^^^ beam vectors;^ generating a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^reporting the CSI report to the network node.In the following, the phrase ‘maximum allowable amplitude coefficient value’,‘maximum allowable amplitude value’ and ‘maximum allowable amplitude coefficient’are used interchangeably and may have the same meaning. The phrase ‘beam vector’and vector and ‘spatial vector’ are used interchangeably and may have the samemeaning. The phrase “precoding matrix” and “precoder matrix” are usedinterchangeably and may have the same meaning. The information element n1-n2-codebookSubsetRestriction is a RRC configured information element first introduced in the 3GPP New Radio Phase 1. The informationelement n1-n2-codebookSubsetRestriction forms the bit-sequence ^ = ^^^^, wherebit sequences concatenated to form bit sequence B. The wireless device is configuredwith restrictions for ^ groups out of ^^^^ groups, wherein each group comprises ^^^^orthogonal vectors. The remaining ^^^^ − ^ groups are not restricted. The ^ groupsare ordered according to the equation ^(^) = − 1}and ^^ ∈ {0, … , ^^ − 1} and wherein is the group index and ^ = 0, … , ^ − 1 denotesthe index of the ^ groups configured with restrictions and the indices are assignedsuch that ^(^) increases as ^ increases. The bit-sequence ^^ is a indicator and indicates the ^ groups configured with restrictions. The second bitsequence ^(^)^is the concatenation of bit sequences ^^ , ^ = 0,1, … , ^ − 1 given by^ = ^(^)(^) … ^(^^^) corresponding to the group indic (^)^ ^^^ ^ es ^ , where ^ is the numberof restricted oversampling groups. The ^ restricted oversampling groups aredetermined by the wireless device based on the bit-sequence ^^which shall be configured to the wireless device by the network. The bit sequence ^(^)^ is of length Bits ^(^,^^^^^^^)^ … ^(^,^)^ . Bits amplitude coefficie(^) nt ^^,^for the vector in group ^(^)indexed by ^^, ^^, where the maximum amplitudecoefficients are given in the Table 1. The typical value of ^ is equal to 4.Table 1: Maximum allowed amplitude coefficients for restricted vectors Bits Maximum Amplitude (^,^(^ )^^,^(^^^^^^^)^ ^^ ^^ ^^)^^ ^ ^^^coefficient ^(^) ^,^00 001 √0.2510 √0.511 1Oversampling factorsIn certain embodiments, the values of ^^ and ^^ are configured via the higher layerinformation element n1-n2-CodebookSubsetRestriction. In certain embodiments, theoversampling factors ^^and ^^associated with ^^-th dimension and ^^-th dimensionare determined by the wireless device or fixed in the specification. In some examples,the wireless determines the oversampling factors based on the configured values of ^^and ^^. Here, ^^and ^^are the number of columns and rows of the antenna port layout at the network node, respectively. The oversampling factors ^^and ^^areassociated with the column dimension and row dimension of the antenna port layout,respectively.In certain embodiments, the oversampling factors are dependent on the product of thevalue ^^ and value ^^, wherein the oversampling factors ^^ and ^^ for ^^^^ > ^^aresmaller than the oversampling factors ^^ and ^^ for ^^^^ ≤ ^^, wherein ^^is thethreshold value, and wherein ^^ > 1 and ^^ > 1. For larger values of ^^ and ^^, thedirectivity of the spatial beam increases compared to smaller values of ^^ and ^^.Therefore, using large oversampling factors for the ^^-th dimension and the ^^-th dimension may not be needed. In one example, the threshold value ^^is equal to 16. In another example, the threshold value ^^is equal to 24. In a further example, the threshold value ^^is equal to 32. In a further example, the threshold value ^^is equal to 64.In one example, for ^^^^ > 16, the oversampling factors ^^ and ^^ are given by 2and 2, respectively, whereas for ^^^^ ≤ 16, the oversampling factors ^^ and ^^ aregiven by 4 and 4, respectively.In certain embodiments, the oversampling factors ^^and ^^are dependent on therank indicator RI. In some examples, for ^^ ≤ 2, ^^ and ^^ are given by 4 and 4,respectively, whereas for ^^ > 2, ^^ and ^^ are given by 2 and 2, respectively. Insome examples, for ^^ ≤ 2, ^^ and ^^ are given by 2 and 2, respectively, whereasfor ^^ > 2, ^^ and ^^ are given by 4 and 4, respectively. Codebook Subset RestrictionIn certain embodiments, the wireless device is configured with restriction for one ormore oversampling groups out of ^^^^ oversampling groups, wherein the one or moreoversampling groups that are restricted comprise information bits associated with themaximum amplitude coefficients for less than ^^^^beam vectors. In some examples, the number of oversampling groups configured for restriction is dependent on the values of ^^and ^^. In some examples, the number of oversampling groups configured for restriction is dependent on the values of ^^and ^^. In certain embodiments, when the product of ^^and ^^is greater than a thresholdvalue i.e., ^^^^ > ^^, the number of oversampling groups configured for restriction issmaller than the number of oversampling groups configured for restriction when theproduct of ^^ and ^^ is smaller than or equal to a threshold value i.e., ^^^^ ≤ ^^,wherein ^^ is the threshold value and wherein ^^ > 1 and ^^ > 1. In some examples,^^ ∈ {16,24,32,48,64}. In one example, for ^^^^ > 16, the number of oversamplinggroups configured for restriction is given by 2, whereas for ^^^^ ≤ 16, the number ofoversampling groups configured for restriction is given by 4.In certain embodiments, when the product of ^^and ^^is greater than a thresholdvalue i.e., ^ ^^^^ > ^ , the number of oversampling groups configured for restriction isgreater than the number of oversampling groups configured for restriction when theproduct of ^^ and ^^ is smaller than or equal to a threshold value i.e., ^^^^ ≤ ^^,wherein ^^ is the threshold value, and wherein ^^ > 1 and ^^ > 1. In some examples,^^ ∈ {16,24,32,48,64}. In one example, for ^^^^ > 16, the number of oversamplinggroups configured for restriction is given by 8, whereas for ^^^^ ≤ 16, the number ofoversampling groups configured for restriction is given by 4.In certain embodiments, when the product of ^^ and ^^ is smaller than or equal to athreshold value i.e., ^^^^ ≤ ^^, the number of oversampling groups configured forrestriction is smaller than the number of oversampling groups configured for restrictionwhen the product of ^^ and ^^ is greater than a threshold value i.e., ^^^^ > ^^,wherein ^^ is the threshold value, and wherein ^^ > 1 and ^^ > 1. In some examples,^^ ∈ {4,8,16}. In one example, for ^^^^ ≤ 4, the number of oversampling groupsconfigured for restriction is given by 2, whereas for ^^^^ > 4, the number ofoversampling groups configured for restriction is given by 4. In certain embodiments, when the product of ^^and ^^is greater than a threshold value, ^’, the number of restricted oversampling groups is equal to the product of ^^and ^^. In certain embodiments, when the product of ^^and ^^is greater than a threshold value, ^’, the number of oversampling groups configured for restriction isfixed to 4 for different values of ^^ and ^^ or different pairs of (^^, ^^) values. In someexamples, the threshold value ^’ is equal to 16. In some examples, the threshold value^’ is equal to 24. In some examples, the threshold value ^’ is equal to 32. In someexamples, the threshold value ^’ is equal to 64.In certain embodiments, when the number of oversampling groups configured forrestriction is equal to the total number of oversampling groups i.e., the product of ^^and ^^, all oversampling groups are configured for restriction and the wireless deviceis not indicated with the oversampling groups configured for restriction as alloversampling groups are restricted. In this case, the bit-sequence ^^ is empty in theinformation element n1-n2-CodebookSubsetRestriction.In certain embodiments, the wireless device is configured with one or more sets ofoversampling groups for restriction, wherein each set comprise one or moreconsecutive or non-consecutive oversampling groups. In some examples, for ^^ = 4and ^^ = 2, there are eight oversampling groups and two sets of oversampling groups,wherein each set comprise four oversampling groups. In one example, the two sets ofoversampling groups comprise consecutive oversampling groups {0,1,2,3} and{4,5,6,7}, respectively. In another example, the two sets of oversampling groups comprise non-consecutive oversampling groups {0,2,4,6} and {1,3,5,7}, respectively.In some other examples, for ^^ = 2 and ^^ = 2, there are four oversampling groupsand two oversampling sets, wherein each set comprises two oversampling groups. Inone example, the two sets of oversampling groups comprise consecutiveoversampling groups {0,1} and {2,3}, respectively. In another example, the two sets of oversampling groups comprise non-consecutive oversampling groups {0,2} and {1,3}, respectively. In some examples, the number of oversampling groups in each set of oversampling groups may be identical or not identical. The wireless device may beconfigured with either one set or two or more sets of oversampling groups.In certain embodiments, when the number of sets of oversampling groups configuredfor restriction is equal to the total number of sets of oversampling groups i.e., when all sets of oversampling groups are configured for restriction, the wireless device is notindicated with the sets of oversampling groups configured for restriction as all sets ofoversampling groups are restricted. In this case, the bit-sequence ^^is empty in the information element n1-n2-CodebookSubsetRestriction.In certain embodiments, when a set of oversampling groups configured for restrictioncomprises all oversampling groups i.e., the product of ^^and ^^, all oversampling groups are configured for restriction and the wireless device is not indicated with theset of oversampling groups configured for restriction as all oversampling groups arerestricted. In this case, the bit-sequence ^^is empty in the information element n1-n2- CodebookSubsetRestriction. In certain embodiments, the oversampling groups are ordered according to theequation ^^^^ + ^^, where = 0, … , ^^ − 1 and ^^ = 0, … , ^^ − 1. The first ^^ groupsfrom left to right are associated with index ^^ = 0, the second ^^ groups from left toright are associated with index ^^ = 1 and so on and the last ^^ groups from left toright are associated with index ^^ = ^^ − 1. The ^^ groups associated with an index ^^are ordered in an increasing order from left to right. In certain embodiments, the oversampling groups are ordered according to theequation ^^^^ + ^^, where = ^^ − 1, … ,0 and ^^ = ^^ − 1, … , 0. The first ^^ groupsfrom left to right are associated with index ^^ = ^^ − 1, the second ^^ groups from leftto right are associated with index ^^ = ^^ − 2 and so on and the last ^^ groups fromleft to right are associated with index ^^ = 0. The ^^ groups associated with an index^^are ordered in a decreasing order from left to right. In certain embodiments, the oversampling groups are ordered according to theequation ^^^^ + ^^, where − 1 and ^^ = 0, … , ^^ − 1. The first ^^ groupsfrom left to right are associated with index = 0, the second ^^ groups from left toright are associated with index = 1 and so on and the last ^^ groups from left toright are associated with index = ^^ − 1. The ^^ groups associated with an index ^^are ordered in an increasing order from left to right. In certain embodiments, the oversampling groups are ordered according to theequation ^^^^ + ^^, where = ^^ − 1, … ,0 and ^^ = ^^ − 1, … ,0. The first ^^ groupsfrom left to right are associated with index = ^^ − 1, the second ^^ groups from leftto right are associated with index ^^ = ^^ − 2 and so on and the last ^^ groups fromleft to right are associated with index = 0. The ^^ groups associated with an indexare ordered in a decreasing order from left to right.In some examples, each oversampling group comprises ^^ consecutive groupsassociated with index ^^, and ^^ consecutive groups associated with index ^^, where some examples, ^^ < ^^ and ^^ < ^^. Insome examples, ^^ < ^^ and ^^ = 1. In some examples, ^^ = 1 and ^^ < ^^.The oversampling groups in the first dimension may be configured to the wireless device via a ^^-length bitmap. The oversampling groups in the second dimension may be configured to the wireless device via a ^^-length bitmap. The oversampling groups in the first and second dimension may be configured to the wireless device via a ^^+ ^^-length bitmap. The oversampling groups or sets of oversampling groups configured for restrictionmay be indicated to the wireless device via a bit-sequence ^^.Each oversampling group may consist of ^^^^beam vectors and each beam vector inan oversampling group may be associated with an index ^, where = 0,1, … , − 1.In certain embodiments, the ^^^^beam vectors are ordered according to the equation^^^^ + ^^, where ^^ = 0, … , ^^ − 1 and ^^ = 0, … , ^^ − 1. The first ^^ beam vectorsfrom left to right are associated with index ^^ = 0, the second ^^ beam vectors fromleft to right are associated with index ^^ = 1 and so on and the last ^^ beam vectorsfrom left to right are associated with index ^^ = ^^ − 1. The ^^ beam vectorsassociated with an index ^^are ordered in an increasing order from left to right. In certain embodiments, the ^^^^beam vectors are ordered according to the equation^^^^ + ^^, where ^^ = ^^ − 1, … , 0 and ^^ = ^^ − 1, … , 0. The first ^^ beam vectorsfrom left to right are associated with index ^^ = ^^ − 1, the second ^^ beam vectorsfrom left to right are associated with index ^^ = ^^ − 2 and so on and the last ^^ beamvectors from left to right are associated with index ^^ = 0. The ^^ beam vectorsassociated with an index ^^are ordered in a decreasing order from left to right. In certain embodiments, the ^^^^beam vectors are ordered according to the equation^^^^ + ^^, where ^^ = 0, … , ^^ − 1 and ^^ = 0, … , ^^ − 1. The first ^^ beam vectorsfrom left to right are associated with index ^^ = 0, the second ^^ beam vectors fromleft to right are associated with index ^^ = 1 and so on and the last ^^ beam vectorsfrom left to right are associated with index ^^ = ^^ − 1. The ^^ beam vectorsassociated with an index ^^are ordered in an increasing order from left to right. In certain embodiments, the ^^^^beam vectors are ordered according to the equation^^^^ + ^^, where ^^ = ^^ − 1, … , 0 and ^^ = ^^ − 1, … , 0. The first ^^ beam vectorsfrom left to right are associated with index ^^ = ^^ − 1, the second ^^ beam vectorsfrom left to right are associated with index ^^ = ^^ − 2 and so on and the last ^^ beamvectors from left to right are associated with index ^^ = 0. The ^^ beam vectorsassociated with an index ^^are ordered in a decreasing order from left to right.In certain embodiments, the maximum allowable amplitude coefficient configured fora ^-th vector among the one or more oversampling groups associated with a set ofoversampling groups configured for restriction is identical, wherein ^ = 0,1, … , −1. In some examples, one set of oversampling groups comprising oversamplinggroups {1,2} is configured for restriction and the allowable amplitude coefficient for thefirst vector in oversampling group 1 and oversampling group 2 is given by 1 and the allowable amplitude coefficient for the second vector in the oversampling group 1 andoversampling group 2 is given by 0 and so on. In some examples, a set ofoversampling groups comprises all or a proper subset of ^^^^ oversampling groups.Here, a proper subset comprises less than ^^^^oversampling groups. In some examples, the one or more sets of oversampling groups configured for ^ restriction are indicated to the wireless device via a ^log^^ ^^^^-bit combinatorialindicator, where ^ is the total number of sets of oversampling groups is thenumber of oversampling sets configured for restriction. Each set of oversamplinggroups comprise up to ^ consecutive or non-consecutive oversamplinggroups. In some examples, the one or more sets of oversampling groups configuredfor restriction are indicated to the wireless device via a bitmap of length ^ andcomprise ones and ^ − zeros, and wherein ^ is the total number ofoversampling sets and is the number of oversampling sets configured for restriction. In certain embodiments, the wireless device is configured with restriction for one or more oversampling groups out of ^^^^oversampling groups, wherein the one or more oversampling groups that are restricted comprise information bits associated with the maximum amplitude coefficients for less than ^^^^vectors. In certain embodiments, for an oversampling group or for a set of oversampling groups configured for restriction, the wireless device is configured with a bit sequence indicating the maximum amplitude coefficient values. The number of indicated maximum coefficient values can be either ^^^^or less than ^^^^.In certain embodiments, for an oversampling group or for a set of oversampling groupsconfigured for restriction, the wireless device is configured with a bit sequenceindicating the maximum amplitude coefficient values for a subset of ^^^^ beamvectors, wherein in the subset comprises less than ^^^^ vectors. In some examples,the subset comprises ^ beam vectors and are given by the consecutive indices ^ = or ^ = ^ + 0, … , ^ + ^ − 1, and wherein ^ ∈ {0, … , ^^^^ − 1}. In someother examples, the subset comprises ^ beam vectors and are given by non-consecutive indices ^ = 0, ^, … , (^ − 1)^, or ^ = ^ + 0, ^ + ^ … , ^ + ^(^ − 1), andwherein ^ ∈ {0, … , ^^^^ − 1} and ^ is an integer. In the above examples, only ^ beamvectors are restricted and the remaining ^^^^ − ^ vectors are not restricted.In some examples, the value of ^ is fixed in the specification or determined by thewireless device from the values of ^^and ^^and / or configured to the wireless device.In some examples, the value of ^ is different for different values of ^^ and ^^ ordifferent (^^, ^^) pairs.In certain embodiments, for an oversampling group or for a set of oversampling groups configured for restriction, the wireless device is configured with a bit sequenceindicating the maximum amplitude coefficient values for ^^′ beam vectors out of ^^beam vectors and ^^′ beam vectors out of ^^ beam vectors. In some examples, ^^^< ^^^and ^^ < ^^. In some examples, ^^^ < ^^ and ^^^ < ^^ and ^^^ = ^^. In someexamples, ^^^ = ^^ and ^^^ < ^^. In some examples, ^^^ = 1 and ^^^ ≤ ^^. In someexamples, ^^^ ≤ ^^ and ^^^ = 1.In certain embodiments, for an oversampling group or for a set of oversampling groupsconfigured for restriction, the wireless device is configured with a bit sequence of length(^^^ + ^^^)^, where R is a number of bits used to indicate the maximum allowedamplitude coefficient value for each beam vector. In certain embodiments, the set of oversampling groups comprise all or a propersubset of ^^^^ oversampling groups. Here, a proper subset comprises less than ^^^^oversampling groups.For example, for ^^ = 8 and ^^ = 2, there are 16 beam vectors or spatial beams ineach oversampling group, whereas for ^^ = 16 and ^^ = 2, there are 32 beam vectorsor spatial beams in each oversampling group. As the value of ^^and / or ^^increase, the number of beam vectors or spatial beams increase for increasing values of ^^and / or ^^. When (^^^^) = (8,2), X number of beam vectors or spatial beams cover aregion of interest, whereas for (^^^^) = (16,2), 2X number of beam vectors or spatialbeams cover the same region of interest. Therefore, one way to reduce theconfiguration overhead is to consider identical values of amplitude restriction for a setof consecutive beam vectors or spatial beams. Therefore, the size of the bitmapindicating the amplitude restriction or the maximum allowed amplitude coefficients orvalues may be reduced. In certain embodiments, for an oversampling group or for a set of oversampling groups configured for restriction, a single maximum amplitude coefficient value may beconfigured for a beam group comprising ^ beam vectors. In some examples, ^ ∈{2,4,8}. In some examples, ^ > 1. In some examples, ^ = 1.In some examples, the beam group comprising S beam vectors has consecutiveindices, e.g., {^, ^ + 1}. In another example, the beam group comprising ^ vectors hasnon-consecutive indices, e.g., {^, ^ + 2}. In some examples, ^ is derived from thevalues of ^^ and ^^ i.e., ^ . In some examples, the value of ^ is fixed in thespecification or determined by the wireless device from the values of ^^and ^^and / orconfigured to the wireless device. In some examples, the value of ^ is different fordifferent values of ^^ and ^^ or different (^^, ^^) pairs.In certain embodiments, a set of consecutive ^ bits indicating the maximum allowedamplitude coefficient value may be associated with a beam group comprising ^ beamvectors. In some examples, the group of vectors are associated with consecutiveindices among ^^^^indices. In one example, the group of vectors are associated withnon-consecutive indices among ^^^^ indices. In some examples, the number of beam. In some examples, the number of beam groups is equal to In certain embodiments, the ^ beam vectors may be associated with ^^^consecutivebeam vectors out of ^^ beam vectors and ^^^ beam vectors out of ^^ beam vectors .In some examples ^ = ^^^ or ^ = ^^ + ^^. In som ^ ^^^^ ^ ^ e examples, ^^ = 1 and ^^ = ^^.In some examples, ^^^ = ^^ and ^^^ = 1. In some examples, ^^ ^^ = 1 and ^^ < ^^. Insome examples, ^^^ < ^^ and ^^^ = 1. In some examples, ^^ ^^ < ^^ and ^^ < ^^.In some options, the number of maximum allowed amplitude coefficient valuesindicated via the bit-sequence ^^ associated with an oversampling group or a set ofoversampling groups is given by ^^^^^ / (^^^^^^). In some options, the number of maximum allowed amplitude coefficient values indicated via the bit-sequence ^^associated with an oversampling group or a set ofoversampling groups is given by (^ ^^ + ^^)^ / (^^ + ^^^). In certain embodiments, the number of maximum allowed amplitude coefficient values indicated via bit-sequence ^^associated with an oversampling group or a set of oversampling groups may not be dependent on the values of ^^and ^^but ratherfixed for different values of ^^ and ^^ or different values of (^^, ^^) pairs.In some examples, the length of the bit-sequence for ^^ = 8 and ^^ = 3 is given by12R or 24R. In some examples, the length of the bit-sequence for ^^ = 6 and ^^ = 4is given by 12R or 24R. In some examples, the length of the bit-sequence for ^^ = 16and ^^ = 2 is given by 16R or 24R or 32R. In some examples, the length of the bit-sequence for ^^ = 8 and ^^ = 4 is given by 16R or 24R or 32R. In some examples,the length of the bit-sequence for ^^ = 16 and ^^ = 4 is given by 16R or 24R or 32Ror 48R or 64R. In some examples, the length of the bit-sequence for ^^ = 8 and ^^ =8 is given by 16R or 24R or 32R or 48R or 64R. Here, R is the number of bits used toindicate the maximum allowed amplitude coefficient values.In certain embodiments, the length of the bit-sequence indicating the maximumallowed amplitude coefficient values for the ^^^^^^ ^^^ vectors is given by^ , where R is the number of bits used to indicate the maximum allowed amplitude coefficient valueand ^ is the parameter to control the configuration overhead. In some examples, thevalue of ^ is greater than 1 such that the length of the bit-sequence associated withan oversampling group, or a set of oversampling groups configured for restriction haslength less than ^^^^^.In certain embodiments, when single bit is used to indicate the maximum allowedamplitude coefficient or value, i.e., when ^ = 1, bit 0 indicates a maximum allowedamplitude coefficient value of 0 and bit 1 indicates a maximum allowed amplitudecoefficient value of 1 or vice versa. In contrast to using ^ > 1, using ^ = 1, furtherreduces the configuration indication overhead as the length of the bit-sequence ^^which is used to indicate the maximum allowable amplitude coefficient values for an oversampling group configured for restriction becomes independent of R.In certain embodiments, the parameter ^ is dependent on the values of ^^ and ^^ orpair. In certain embodiments, the values of the parameter ^ is fixed in thespecification for different values of ^^ and ^^ or (^^, ^^) pair.In certain embodiments, the wireless device is configured to determine the values of ^^and ^^from the bit-sequence configured for amplitude restriction or codebook subset restriction. When the length of the second bit-sequence associated with eachrestricted oversampled group is less than ^^^^^ bits, the wireless device may not beable to determine the actual combination or (^^^^) values. Hence, the wireless deviceneeds to be configured with other parameters to aid the wireless device to correctlydetermine the actual (^^^^) combination or exact values of ^^ and ^^.In some examples, the wireless device may be configured with a⌈log^(64)⌉-lengthbitmap. Here, 64 is the maximum number of antenna ports supported per polarization.Using this indicator, the number of total antenna ports can be determined by the wireless device. In some examples, the wireless device may be configured with a ⌈log^(16)⌉-bitindicator to indicate the value of ^^. Here, 16 is the maximum number of antenna portssupported per polarization in the vertical dimension (columns) of the antenna portlayout. In some examples, the wireless device may be configured with a ⌈log^(8)⌉-bitindicator to indicate the value of ^^. Here, 8 is the maximum number of antenna portssupported per polarization in the horizontal dimension (rows) of the antenna port layout. In some examples, the wireless device may be configured with a 7-bit indicator to indicate the values of ^^and ^^. The first 4 bits are used to indicate the value of ^^and the remaining 3 bits are used to indicate the value of ^^. In certain embodiments, the precoder may be based on Rel.16 Type-II codebook, or Rel.18 Type-II codebook or Rel.19 Type-I codebook, where at least one beam vector is used to determine the precoder matrix. Referring to Figure 3, there is illustrated a method performed by a wireless device (700) according to some of the previously described embodiments. The method is performed by the wireless device (700) in a wireless communications network. The method comprises: ^receiving (301) from a network node a higher layer configuration comprisingan indication of a number of oversampling groups, wherein each indicated oversampling group indicates maximum allowable amplitude values for a proper subset of beam vectors from a set of ^^^^beam vectors for restricting an amplitude associated with a beam vector; ^calculating (302) a precoding matrix, the precoding matrix being based onat least one beam vector from the set of ^^^^ beam vectors;^ generating (303) a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^reporting (304) the CSI report to the network node.Referring to Figure 4, there is illustrated a method performed by a wireless device (700) according to some of the previously described embodiments. The method is performed by the wireless device (700) in a wireless communications network. The method comprises: ^receiving (401) from a network node a higher layer configuration comprisingan indication of a number of oversampling groups, wherein each indicated oversampling group indicates a number of maximum allowable amplitude values, X, and a number of beam groups, Y, wherein a beam group comprises a set of beam vectors, and wherein a maximum allowable amplitude value is used for restricting an amplitude associated with a beam vector; ^calculating (402) a precoding matrix, the precoding matrix being based onat least one beam vector from the set of ^^^^ beam vectors;^ generating (403) a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^reporting (404) the CSI report to the network node.In certain embodiments, the higher layer configuration comprises an indication of a set of oversampling groups, wherein the set of oversampling groups comprises all oversampling groups. In certain embodiments, the higher layer configuration comprises a bitmap ^, whereinthe bitmap ^ comprises two bitmaps, a first bitmap ^^ and a second bitmap ^^, wherein^ = ^^^^.In certain embodiments, a number of oversampling groups, ^, out of ^^^^oversampling groups are indicated to the wireles device via the first bitmap ^^. In certain embodiments, each oversampling group comprises ^^^^beam vectors.In certain embodiments, when the number of oversampling groups configured forrestriction is equal to the total number of oversampling groups, the wireless device isnot indicated with the number of oversampling groups configured for restriction andthe first bitmap ^^is empty.In certain embodiments, for each indicated oversampling group or for the indicated setof oversampling groups, the maximum allowable amplitude values are indicated to thewireless device via the second bitmap ^^. In certain embodiments, the second bitmap ^^is the concatenation of bit sequences ^(^) ( ) ( )^ , ^ = 0,1, … , ^ − 1 given by ^^ = ^(^)^^^^ … ^ ^^^^ , wherein ^ is the number ofindicated oversampling groups.In certain embodiments, the maximum allowable amplitude value for a ^-th beamvector is identical in every indicated oversampling group, wherein ^ = 0,1, … , ^^^^ − 1or ^ = 0,1, … , ^^ + ^^.In certain embodiments, the maximum allowable amplitude values are indicated to the wireless device via the second bitmap ^^, where ^^comprise a single bit sequence oflength In certain embodiments, a number of sets of oversampling groups, out of ^ setsof oversampling groups are indicated to the wireless device via the first bitmap ^^,where ^ is the total number of sets of oversampling groups and is the number ofoversampling sets configured for restriction.In certain embodiments, for each indicated set of oversampling groups, the maximumallowable amplitude values are indicated to the wireless device via the second bitmap ^^, wherein a set of oversampling groups comprise at least two consecutive or non- consecutive oversampling groups.In certain embodiments, the second bitmap ^^ is a concatenation of bit sequences^(^)^ , ^ = 0,1, … , − 1 given by ^^ = ^(^)^ ^(^)^ … ^(^^^^^), wherein is the numberof oversampling sets configured for restriction.In certain embodiments, the bit-sequence ^(^) (^)^ or ^^indicates a maximum allowableamplitude value for a subset of the ^^^^ beam vectors comprising ^ beam vectors,wherein ^ < ^^^^.In certain embodiments, the ^ beam vectors are associated with consecutive or non-consecutive indices out of ^^^^indices. In certain embodiments, the maximum allowable amplitude coefficient values areconfigured for a subset comprising ^ beam vectors.In certain embodiments, the maximum allowable amplitude coefficient values are notconfigured for the remaining ^^^^ − ^ beam vectors. In certain embodiments, the length of the bit-sequence ^(^)^ or is ^^, wherein ^ is the number of bits used to indicate the maximum allowable amplitude value for each beam vector.In certain embodiments, the subset comprises the first ^ beam vectors out of ^^^^beam vectors out of the ^^^^ beam vectors.In certain embodiments, ^ = ^, and ^ = and such that a single maximumallowable amplitude coefficient is associated with a beam group comprising ^ beamvectors out of ^^^^ beam vectors and wherein ^ > 1.In certain embodiments, the wireless device is configured with ^ beam groups,wherein a beam group comprises ^ beam vectors, wherein ^ > 1, and wherein allbeam vectors in the beam group are associated with the same maximum allowable amplitude coefficient.In certain embodiments, the ^ beam vectors are associated with consecutive indicesor non-consecutive indices out of ^^^^indices.In certain embodiments, ^ = ^ such that a single allowable amplitude coefficient valueis associated with a beam group comprising ^ beam vectors out of the set of ^^^^beam vectors, and wherein ^ > 1.In certain embodiments, In certain embodiments, the ^ beam vectors are associated with consecutive indicesor non-consecutive indices out of ^^^^indices or ^^+^^indices.In certain embodiments, the S beam vectors are associated with ^^^beam vectors out of ^^beam vectors and ^^^beam vectors out of ^^beam vectors. In certain embodiments, ^^^ < ^^ and ^^^ ≤ ^^, or ^^^ ≤ ^^ and ^^^ < ^^, or ^^^ < ^^ and^^^ < ^^.In certain embodiments, ^ = ^^^^^ ^^ or ^ = ^^ + ^^^. In certain embodiments, the maximum allowable amplitude coefficient value configured for a ^-th vector among all oversampling groups associated with a set ofoversampling groups configured for restriction is identical, wherein ^ = 0,1, … , ^^^^ −1. In certain embodiments, the length of the bit-sequence ^(^) (^)^ or ^^ and wherein R is the number of bits used to indicate the maximum allowable amplitudecoefficient value for each beam group comprising ^ beam vectors.In certain embodiments, R = 1 or R = 2.In certain embodiments, R = 1, the maximum allowable amplitude values are given by0 and 1.In certain embodiments, for R = 2, the maximum allowable amplitude values are givenby 0, √0.25, √0.5 and 1.In certain embodiments, wherein for ^^^^ > 16, the number of indicated oversamplinggroups is given by ^ = ^^^^.In some examples, ^ < ^^^^.In order to perform the previously described process or method steps performed bythe wireless device or UE, there is also provided a wireless device. Figure 7 illustratesa simplified block diagram depicting a wireless device 700. The wireless device 700 comprises a processor 710 or processing circuit or a processing module or a processor means 710; a receiver circuit or receiver module 740; a transmitter circuit or transmitter module 750; a memory module 720, a transceiver circuit or transceiver module 730 which may include the transmitter circuit 750 and the receiver circuit 740. The wireless device 700 further comprises an antenna system 760 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. The wireless device may be a UE or an IoT device. The wireless device 700 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 wireless device comprising the processor and the memory contains instructions executable by the processor, whereby the wireless device 700 is operative or is configured to performany one of the embodiments related to the wireless device as previously described.The processing module / circuit 710 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 710 controls the operation of the wireless device and its components. Memory (circuit or module) 720 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 processor710. In general, it will be understood that the wireless device 700 in one or moreembodiments includes fixed or programmed circuitry that is configured to carry out the operations in any of the embodiments disclosed herein. In at least one such example, the processor 710 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 700 may comprise additional components. The wireless device 700 by means of processor 710 executes instructions contained in the memory 720 whereby the wireless device is operative to perform any one of the previously described embodiments related to the actions performed by the wirelessdevice, some of which are presented in appended claims.There is also provided a computer program comprising instructions which when executed by the processor 710 of the wireless device cause the processor 710 to carry out the method according to any one of the previously described embodiments. Referring to Figure 5, there is illustrated a method performed by a network node (800) according to some of the previously described embodiments. The method comprises: ^transmitting (501) to a wireless device a configuration comprising anindication of a number of oversampling groups, wherein each indicatedoversampling group indicates maximum allowable amplitude values for a proper subset of beam vectors from a set of ^^^^beam vectors for restricting an amplitude associated with a beam vector; for enabling the wireless device to: ocalculate a precoding matrix, the precoding matrix being based on atleast one beam vector from the set of ^^^^ beam vectors;o generate a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^receiving (502) from the wireless device the CSI report.Referring to Figure 6, there is illustrated a method performed by a network node (800) according to some of the previously described embodiments. The method comprises: ^transmitting (601) to a wireless device a configuration comprising anindication of a number of oversampling groups, wherein each indicated oversampling group indicates a number of maximum allowable amplitude values, X, associated with a number of beam vectors, Y, from a set of ^^^^beam vectors and wherein a maximum allowable amplitude value is used for restricting an amplitude associated with a beam vector; for enabling the wireless device to: ocalculate a precoding matrix, the precoding matrix being based on atleast one beam vector from the set of ^^^^ beam vectors;o generate a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^receiving (602) from the wireless device the CSI report.To perform the previously described process or method steps performed by thenetwork node there is also provided a network node. Figure 8 illustrates a block diagram depicting a network node 800. The network node 800 comprises a processor810 or processing circuit or a processing module or a processor means 810; a receivercircuit or receiver module 840; a transmitter circuit or transmitter module 850; a memory module 820, a transceiver circuit or transceiver module 830 which may include the transmitter circuit 850 and the receiver circuit 840. The network node 800 further comprises an antenna system 860 which includes antenna circuitry for transmitting and receiving signals to / from at least the wireless device. The antenna system employs beamforming as previously described. The network node 800 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 800 is operative or is configured to perform any one of the embodiments related to the network node 800 as previously described. The processing module / circuit 810 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 810 controls the operation of the network node and its components. Memory (circuit or module) 820 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 processor810. In general, it will be understood that the network node in one or moreembodiments includes fixed or programmed circuitry that is configured to carry out the operations in any of the embodiments disclosed herein. In at least one such example, the processor 810 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 800 may comprise additional components. The network node 800 may also be viewed as a Transmitter and Receiver Point (TRP). The network node 800 by means of processor 810 executes instructions contained in the memory 820 whereby the network node 800 is operative to perform any one of the previously described embodiments related to the actions performed by the network node. There is also provided a computer program comprising instructions which when executed by the processor 810 of the network node cause the processor 810 to carry out the method according to some embodiments. 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. Throughout this disclosure, the word "comprise" or “comprising” has been used in a non-limiting 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, WiMAX, WiFi, satellite communications, TV broadcasting etc.

Claims

CLAIMS1. A method performed by a wireless device (700) in a wireless communicationsnetwork, the method comprising: ^receiving from a network node a higher layer configuration comprising anindication of a number of oversampling groups, wherein each indicated oversampling group indicates maximum allowable amplitude values for a proper subset of beam vectors from a set of ^^^^beam vectors for restricting an amplitude associated with a beam vector; ^calculating a precoding matrix, the precoding matrix being based on at leastone beam vector from the set of ^^^^ beam vectors;^ generating a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^reporting the CSI report to the network node.

2. A method performed by a wireless device (700) in a wireless communicationsnetwork, the method comprising: ^receiving from a network node a higher layer configuration comprising anindication of a number of oversampling groups, wherein each indicated oversampling group indicates a number of maximum allowable amplitude values, X, and a number of beam groups, Y, wherein a beam group comprises a set of beam vectors, and wherein a maximum allowableamplitude value is used for restricting an amplitude associated with a beamvector; ^calculating a precoding matrix, the precoding matrix being based on at leastone beam vector from the set of ^^^^ beam vectors;^ generating a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^reporting the CSI report to the network node.

3. The method of claim 1 or 2, wherein the higher layer configuration comprises anindication of a set of oversampling groups, wherein the set of oversampling groupscomprises all oversampling groups.

4. The method of any of claims 1-3, wherein the higher layer configuration comprisesa bitmap ^, wherein the bitmap ^ comprises two bitmaps, a first bitmap ^^ and asecond bitmap ^^, wherein ^ = ^^^^.

5. The method of claim 4, wherein the number of oversampling groups, ^, out of ^^^^oversampling groups are indicated to the wireless device via the first bitmap ^^.

6. The method of claim 4 or 5, wherein each oversampling group comprises ^^^^beam vectors.

7. The method of claim 4, wherein when the number of oversampling groupsconfigured for restriction is equal to the total number of oversampling groups, the wireless device is not indicated with the number of oversampling groups configured for restriction and the first bitmap ^^ is empty.

8. The method of claim 4, wherein for each indicated oversampling group or for theindicated set of oversampling groups, the maximum allowable amplitude coefficientvalues are indicated to the wireless device via the second bitmap ^^.

9. The method of claim 8, wherein the second bitmap ^^ is a concatenation of bitsequences ^(^)^ , ^ = 0,1, … , ^ − 1 given by ^^ = ^(^)(^) (^^^)^^^ … ^^ , wherein ^ isthe number of indicated oversampling groups.10.The method of claim 8, wherein the second bitmap ^^ is a concatenation of bitsequences ^(^) (^)^ , ^ = 0,1, … ,given by ^^ = ^(^)^ ^^ … ^(^^^^^), wherein =1 is the number of oversampling sets configured for restriction.11.The method of claim 9 or 10, wherein the bit-sequence ^(^)^ orindicates a maximum allowable amplitude coefficient value for a subset of the ^^^^ beamvectors comprising ^ beam vectors, wherein ^ < ^^^^.The method of claim 11, wherein the ^ beam vectors are associated withconsecutive or non-consecutive indices out of ^^^^ indices.The method of claim 11, wherein the maximum allowable amplitude coefficientvalues are indicated for a subset of the ^^^^ beam vectors comprising ^ beamvectors. The method of claim 11, wherein the maximum allowable amplitude coefficientvalues are not configured for the remaining ^^^^ − ^ beam vectors.The method of claim 11, wherein the length of the bit-sequence ^(^)^ oris ^^,wherein ^ is the number of bits used to indicate the maximum allowable amplitudevalue for each beam vector.The method of claim 11, wherein the subset of the ^^^^ beam vectors comprisesthe first ^ beam vectors out of the ^^^^ beam vectors.The method according to claim 2 or 3, wherein ^ = ^ such that a single allowableamplitude coefficient value is associated with a beam group comprising ^ beamvectors out of the set of ^^^^ beam vectors, and wherein ^ > 1.The method according to claim 17, wherein ^ =^^^^^or ^ =^ .The method according to claim 17, wherein the ^ beam vectors are associated withconsecutive indices or non-consecutive indices out of ^^^^ indices or ^^+^^indices.The method according to claim 17 or 18, wherein the S beam vectors areassociated with ^^^ beam vectors out of ^^ beam vectors and ^^′beam vectors out of ^^beam vectors. The method according to claim 20, wherein ^^^ < ^^ and ^^^ ≤ ^^, or ^^^ ≤ ^^ and^^^ < ^^, or ^^^ < ^^ and ^^^ < ^^.The method according to claim 21, wherein ^ = ^^′^′ ′^ or ^ = ^^ + ^^′.The method of any of claims 1-3, wherein the maximum allowable amplitudecoefficient value configured for a ^-th vector among all oversampling groups associated with a set of oversampling groups configured for restriction is identical,wherein ^ = 0,1, … , ^^^^ − 1.The method according to claim 9 or 10, wherein the length of the bit-sequencewherein R is the number of bits used to indicate themaximum allowable amplitude coefficient value for each beam group comprising ^ beam vectors.The method of claim 15 or 24, wherein R = 1 or R = 2.The method of claim 25, wherein for R = 1, the maximum allowable amplitudevalues are given by 0 and 1.The method of claim 25, wherein for R = 2, the maximum allowable amplitudevalues are given by 0, √0.25, √0.5 and 1.The method of claim 5, wherein for ^^^^ > 16, the number of indicatedoversampling groups is given by ^ = ^^^^.The method of claim 5, wherein ^ < ^^^^.A method performed by a network node (800), the method comprising^ transmitting to a wireless device a configuration comprising an indication ofa number of oversampling groups, wherein each indicated oversampling group indicates maximum allowable amplitude values for a proper subset of beam vectors from a set of ^^^^beam vectors for restricting an amplitude associated with a beam vector; for enabling the wireless device to: ocalculate a precoding matrix, the precoding matrix being based on atleast one beam vector from the set of ^^^^ beam vectors;o generate a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and^ receiving from the wireless device the CSI report.A method performed by a network node (800), the method comprising^ transmitting to a wireless device a configuration comprising an indication ofa number of oversampling groups, wherein each indicated oversampling group indicates a number of maximum allowable amplitude values, X, and a number of beam groups, Y, wherein a beam group comprises a set of beam vectors, and wherein a maximum allowable amplitude value is usedfor restricting an amplitude associated with a beam vector; for enabling thewireless device to: ocalculate a precoding matrix, the precoding matrix being based on atleast one beam vector from the set of ^^^^ beam vectors;o generate a CSI report comprising a Precoder Matrix Indicator, PMI,indicating the precoding matrix; and ^receiving from the wireless device the CSI report.A network node (800) comprising a processor (810) and a memory (820) containinginstructions executable by said processor (810), whereby the network node (800)is operative to perform the method according to claim 30 or 31.A wireless device, (700) comprising a processor (710) and a memory (720)containing instructions executable by said processor (710), whereby the wirelessdevice (700) is operative to perform the method according to any of claims 1-29.

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