Separate beam indications for data blocks

Abstract

A first apparatus 110 (e.g. a UE) maps 205 a plurality of groups of beams to a plurality of “data blocks” which are to be received from a second apparatus 120 (e.g. a gNB). In the embodiments the “data blocks” are codewords. Each group of the plurality of groups of beams are mapped to one of the plurality of data blocks / codewords. The first apparatus transmits 210 to the second apparatus a plurality of separate beam indicators, each indicating a group of the plurality of groups of beams. The mapping preferably involves the first apparatus performing signal strength measurements on reference signals included in a plurality of downlink beams and using the signal strength measurements to select one or more beams to be included in a group of beams. A first beam (e.g. the strongest beam) may be mapped to a specific layer or pair of layers and a second beam (the second strongest beam) may be mapped to different layers.

Description

[0001] Various example embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to apparatuses, methods and computer readable storage medium for separate beam indications for data blocks. BACKGROUND

[0002] In release (Rei) 19 New Radio (NR) Multiple-Input Multiple-Output (MIMO), it is agreed to extend Type-I channel state information (CSI) reporting for larger number of CSI-reference signal (RS) ports, for example, up to 128. For ranks 1 to 4, it is agreed to support two different codebook schemes (i.e., Scheme-A and Scheme-B) for 48, 64 and 128 ports. Scheme-A and Scheme-B basically are two extensions of Type-I codebook which is introduced in Rei 15. For ranks 5 to 8, some schemes are extended from Scheme-A and Scheme-B. SUMMARY

[0003] In a first aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: map a plurality of groups of beams to a plurality of data blocks, where the plurality of data blocks are to be received from a second apparatus, and each group of the plurality of groups of beams are mapped to one of the plurality of data blocks; and transmit, to the second apparatus, a plurality of separate beam indicators, each of the plurality of separate beam indicators indicating a group of the plurality of groups of beams.

[0004] In a second aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: receive, from a first apparatus, a plurality of separate beam indicators, where each of the plurality of separate beam indicators indicates a group of the plurality of groups of beams, and each group of the plurality of groups of beams are mapped to one of a plurality of data blocks to be transmitted to the first apparatus; and perform precoding for the plurality of data blocks, based on the plurality of separate beam indicators.

[0005] In a third aspect of the present disclosure, there is provided a method. The method comprises: mapping a plurality of groups of beams to a plurality of data blocks, where the plurality of data blocks are to be received from a second apparatus, and each group of the plurality of groups of beams are mapped to one of the plurality of data blocks; and transmitting, to the second apparatus, a plurality of separate beam indicators, each of the plurality of separate beam indicators indicating a group of the plurality of groups of beams.

[0006] In a fourth aspect of the present disclosure, there is provided a method. The method comprises: receiving, from a first apparatus, a plurality of separate beam indicators, where each of the plurality of separate beam indicators indicates a group of the plurality of groups of beams, and each group of the plurality of groups of beams are mapped to one of a plurality of data blocks to be transmitted to the first apparatus; and performing precoding for the plurality of data blocks, based on the plurality of separate beam indicators.

[0007] In a fifth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for mapping a plurality of groups of beams to a plurality of data blocks, where the plurality of data blocks are to be received from a second apparatus, and each group of the plurality of groups of beams are mapped to one of the plurality of data blocks; and means for transmitting, to the second apparatus, a plurality of separate beam indicators, each of the plurality of separate beam indicators indicating a group of the plurality of groups of beams.

[0008] In a sixth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for receiving, from a first apparatus, a plurality of separate beam indicators, where each of the plurality of separate beam indicators indicates a group of the plurality of groups of beams, and each group of the plurality of groups of beams are mapped to one of a plurality of data blocks to be transmitted to the first apparatus; and means for performing precoding for the plurality of data blocks, based on the plurality of separate beam indicators.

[0009] In a seventh aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the third aspect or the fourth aspect.

[0010] It is to be understood that the Summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0012] FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

[0013] FIG. 2 illustrates a signaling diagram for codeword based beam indication according to some example embodiments of the present disclosure;

[0014] FIGS. 3A to 3C illustrates example diagrams of associations between beam and codeword for rank 5, rank 7 and rank 8, respectively, according to some example embodiments of the present disclosure;

[0015] FIG. 4 illustrates an example diagram of an association between beam and codeword for rank 6 according to some example embodiments of the present disclosure;

[0016] FIG. 5 illustrates an example process of data block based beam indication in accordance with some example embodiments of the present disclosure;

[0017] FIG. 6 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0018] FIG. 7 illustrates a flowchart of a method implemented at a second apparatus in accordance with some example embodiments of the present disclosure;

[0019] FIG. 8 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure; and

[0020] FIG. 9 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

[0021] Throughout the drawings, the same or similar reference numerals represent the same or similar element. DETAILED DESCRIPTION

[0022] Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

[0023] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0024] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0025] It shall be understood that although the terms “first,” “second,”..., etc. in front of noun(s) and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another and they do not limit the order of the noun(s). For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0026] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements. 5

[0027] As used herein, unless stated explicitly, performing a step “in response to A” does not indicate that the step is performed immediately after “A” occurs and one or more intervening steps may be included.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used 10 herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, 15 components and / or combinations thereof.

[0029] As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0030] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0031] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4 5G, the fifth generation (5G), 5.5G, the sixth generation (6G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0032] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (IAB) node, a low power node such as a femto, a pico, a non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft network device, and so forth, depending on the applied terminology and technology. In some example embodiments, radio access network (RAN) split architecture comprises a Centralized Unit (CU) and a Distributed Unit (DU) at an IAB donor node. An IAB node comprises a Mobile Terminal (IAB-MT) part that behaves like a UE toward the parent node, and a DU part of an IAB node behaves like a base station toward the next-hop IAB node.

[0033] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. The terminal device may also correspond to a Mobile Termination (MT) part of an IAB node (e.g., a relay node). In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0034] As used herein, the term “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other combination of the time, frequency, space and / or code domain resource enabling a communication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

[0035] As mentioned above, for rank 1 to 4, it is agreed to support two different codebook schemes for 48, 64 and 128 ports. As specified in the 3rd Generation Partnership Project (3GPP) standards, it is agreed that for the Rei-19 Type-I single-panel (SP) codebook refinement for 48, 64, and 128 CSI-RS ports, for rank indicator (RI)=l-4, Scheme-A and Scheme-B are supported.

[0036] In Scheme-A, new (Nl, N2) values are added for the Rel-15 Type-I single-panel codebook mode-1 (L=l) where 2N1N2 (>32) is the total number of CSI-RS ports across aggregated non-zero power (NZP) CSI-RS resources, and for rank-3 / 4, legacy mechanisms for <16 ports are followed.

[0037] In Scheme-B, new (Ni, N2) values are added where N± is the number of spatial domain (SD) DFT beams in the horizontal / Azimuth direction for each polarisation, N2 is the number of SD DFT beams in the vertical / elevation direction and 2N1N2 (>32) is the total number of CSI-RS ports across aggregated NZP CSI-RS resources, and Wi structure and W2 structure are supported. In Wi structure, for each layer, legacy Rel-16 eType-II spatial domain (SD) basis with L=1 is reused to determine the Discrete Fourier Transform (DFT)-based SD basis candidates. For 1 <RI <4, L=1 SD basis vector is independently selected for different layers. The SD basis selection indication includes layer-common (qi,q2) and [log2(^^)] bits for each layer, where q1 and q2 are indices identifying one of the OXO2 SD vector groups of size N}N2 that are orthogonal to one another in both horizontal and vertical direction. It is to be noted that this implies that each of the SD basis vectors is selected from a group of N1N2 orthogonal basis vectors. In W2 structure, layer-specific inter-polarization is co-phased with the alphabet {+1, +j, -1, -j}.

[0038] Scheme-A is a simple extension of Rei 15 Type-I codebook mode 1, for ranks 1 to 4, following the design for <16 ports. Regarding a beam selection strategy, the distinctive feature of this scheme is that the first beam is freely selected from the oversampled 2 dimensional (D) DFT beam grid of size N1O1 x N2O2, where and O2 are the oversampling factors applied to the DFT vectors in the horizontal and vertical dimension, respectively, whereas a second beam for ranks >1 is selected from a candidate set of four beams, which comprises the first beam for rank 2 and does not comprise the first beam for ranks 3 and 4.

[0039] Scheme-B allows free selection of one beam per layer from a candidate set of NyN2 beams that are mutually orthogonal in both horizontal and vertical dimensions. The orthogonal group of N}N2 beams is common across layers and selected from the O}O2 possible orthogonal groups. It is to be noted that each layer has a separate beam indication because the same beam may be selected for two layers. Thus, for rank 4, for example, a UE reports 4 beams from the selected orthogonal group of N}N2 beams, but the number of unique beams may be 2, 3 or 4.

[0040] For Type-I refinement for ranks 5 to 8 and up to 128 ports, some candidate schemes have been identified for down-selection. For example, it is agreed that for the Rel-19 Type-I SP codebook refinement for 48, 64, and 128 CSI-RS ports with RI=5-8, the following candidate schemes are decided, which, for example, includes Schemes 1 to 4.

[0041] In Scheme 1, new (Ni, N2) values are added for the Rel-15 Type-I RI=5 to 8. In Scheme 2, Wi structure indicates independent selection of different ceil (v / 2) SD basis vectors for RI = v, where each SD basis vector is applied to two respective layers except that, if v is odd, the last SD basis vector is applied to the orphan layer. Each of the SD basis vectors is freely selected from a group of N1N2 orthogonal SD DFT basis vectors via combinatorial indication. Mapping between v layers and ceil (v / 2) SD basis vectors and support of 4 selected SD basis vectors for RI=5 to 6 may be for further study. W2 structure indicates for inter-polarization co-phasing, M (e.g., M = 4) codepoints for the orphan layer and M / 2 codepoints for two layers sharing a same SD basis vector and a fixed 7t rotation of inter-polarization co-phasing between two layers sharing a same SD basis vector to achieve layer orthogonality.

[0042] In Scheme 3, the first beam is freely selected and subsequent 2 beams (RI=5 to 6) or 3 beams (RI=7 to 8) are freely selected such that they are orthogonal in at least one dimension (horizontal or vertical). Layers are mapped to the selected SD basis vectors following legacy Rel-15 for RI=5 to 8. One co-phasing across all layers £ {l,j} following legacy Rel-15 Type-I RI=5 to 8

[0043] In Scheme 4, two independently calculated RI= 1 to 4 precoder matrix indicators (PMIs) for RI=5 to 8 are concatenated to reduce UE complexity where each PMI is calculated from the agreed RI=1 to 4 codebook (Scheme-A or Scheme-B) and the channel quality indicator (CQI) for each of two codewords (CWs) is derived assuming it is received by one antenna group of 4 antenna ports. It is for further study whether additional mapping between the two PMIs and the two UE antenna groups is needed. Other schemes are not precluded.

[0044] In addition, Scheme 2 is intended to be the extension of Scheme-B to ranks larger than 4, whereas Schemes 1 and 3 are possible extensions of Scheme-A to ranks larger than 4. Scheme 4 is likely to be dropped from the list of candidate schemes as it targets a use case where a UE uses two receive antenna port groups to decode different MIMO layers.

[0045] Regarding the beam selection, a similar approach is proposed in the candidate schemes for ranks 5 to 8 as is agreed for Scheme-B for ranks 1 to 4, e.g., allowing free beam selection of up to 4 beams within an extended set of orthogonal beams, in at least one or both dimensions. This is different from legacy Rei 15 Type-I for ranks 5 to 8, where only the first beam (anchor beam) is freely selected and the remaining up to 3 beams have a fixed relationship with the first beam.

[0046] In prior art, when beams are common across all layers, like in Type-II codebooks, they are indicated by a single combinatorial indicator indicating the selected combination of L = 2,4 or 6 beams out of an orthogonal group of NtN2 beams, where Nt and N2 are the 2D-DFT codebook horizontal and vertical dimension, respectively, for each polarization.

[0047] If a single beam is selected per layer, like in the recently agreed Scheme-B for Type-I extension for up to 128 ports for ranks 1 to 4, each beam is indicated separately. However, it requires large overhead to extend this approach.

[0048] For physical downlink shared channel (PDSCH) transmission, a fixed mapping of layers to codewords is specified is Table 1 which is an example from Table 7.3.1.3-1 in 3GPP technical specification (TS) 38.211. In Table 1, complex-valued modulation symbols d^q\M^mb — 1) for codeword q may be mapped onto the layers x(0 = ... (i)]T, i= 0, 1,..., MlSy^b — 1 where v is the number of layers and MlSymb ’s the number of modulation symbols per layer. Table 1 Number of layers Number of codewords Codeword-to-layer mapping ’ = ox..XZ-i 1 1 2 1 X' \i) = ■ (2i') layer _ ,,(0) A x^i^d^Qi + Y) symb symb / 3 1 x^i^d^i) xm(i) = d^ (3 / +1) x(2\i) = d(0\3i + 2) 4 1 x(0)( / ) = 4(0)(4 / ') xm(i) = d(0\4i+l) flayer =M(0) / 4 x^2\i) = dm(4i + 2) symb symb / x('3\i) = d(0\4i+ 3) 5 2 x^'Xi) = d(0)(2i) ^( / ) = 4^(2 / +1) 1 / layer = m (°) / 2 = m(1) / 3 (2)() ) symb symb / wmb / x^\i) = d^(3i + \') x^(i) = dm(3i+2) 6 2 x^Xi^d^i) ^( / ) = 4^(3 / + 1) x(2)( / ) = J(0)(3 / +2) A / lay7 / 3 =Mm. / 3 symb symb / symb / +(3)( / ) = 4a)(3 / ) x(4)( / ) = d(1) (3 / +1) x(5)( / ) = 4(1)(3 / +2) 7 2 x(0,( / ) = 4f0)(3 / ) x(1)( / ) = 4^(3 / +1) xi'2\i) = di'GX3i + 2) (3) =44^ / 3=2^ / 4 x^Xi^d^i) ' ' ' x(4)( / ) = 4(1) (4 / +1) x(5\i) = d(2\4i + 2) x(6)( / ) = 4(1)(4 / +3) x(o)(O = d(o)(4O xm(i) = d(0) (4 / +1) . / ^( / ) = / / ^(4 / + 2) . / ^( / ) = / / ^(4 / + 3) 8 2 x(4)( / ) = J(1)(4z) ?5)( / ) = J(1)(4z+1) / 6\z) = / / (n(4z+2) . / 7)(z) = z / (1)(4Z + 3) = M (0) / symb symb / A=Mm / a symb /

[0049] As shown in Table 1, up to rank 4 (i.e., the number of layers = 4), there is only one codeword. The layer (indicated by x)-to-codeword (indicated by the superscript of d) mapping is not relevant in terms of performance because only one encoding is applied across all the layers and any permutation of layers produce the same effect. From rank 5 onwards, there is a split between layers and codewords. In an example of rank 5, the first two layers are mapped to the first codeword and the last three layers are mapped to the second codeword.

[0050] In legacy Rei 15 Type-I, there is also a fixed mapping of beams to layers for each supported rank because in Type-I codebooks each layer is transmitted with a single DFT beam. Therefore, in legacy standards, for ranks larger than 4, when the PDSCH signal is divided in two transport blocks, or codewords, there is a fixed mapping of beams to codeword 1 and codeword 2. This has the advantage of maximizing the CQI of the first codeword by ensuring that the first selected beam (the anchor beam, which is typically the strongest beam) always supports 2 layers of the first codeword, the second beam, which is typically the second strongest beam, is mapped to the first codeword when the first codeword has more than 2 layers (for ranks 6 to 8) and for rank 7 the second beam only supports one layer of the first codeword and no additional layer from the second codeword.

[0051] Therefore, for rank up to 4, there is no issue of mapping beams to layers because there is only one codeword. However, there is a difference whether the beams are assigned to one codeword or another because different codewords have different characteristics, such as different modulation and coding scheme (MCS) levels.

[0052] Table 2 shows the layer-to-codeword mapping and the beam-to-layer mapping for rank 7, respectively, as an example to illustrate the observations above. It is to be noted that the layers in Table 2 correspond to the columns of matrix and the first, second, third and fourth beam are denoted by vlim, Vi» m» and vt'» m'", respectively. Table 2 codebookMode = 1-2 'i.i '1.2 / 2 = 4,A2 = 1 N1O1 o..... 0 0,1 ^,^+(9^^+2(91,^+3(91,0,0,0,0, / 2 NA >4, N2 = 1 0,..., N} — 1 0 0,1 w(7) / ,,,4,+0,,4,+20,,4,+30,,0,0,0,0. / , = 2,N2 = 2 Q,...,N1O1 - 1 0,...,A202-1 0,1 ^++0,,4,,4,+0,, / ,,.^.4.+0,,^+02,¾ Ai >2,N2 = 2 0,..., N1O1 - 1 n2o2 0,1 4,,4,+O„4,,4,+O„42,4,,42+O2,++O2,)2 N± >2,N2 >2 0,..., - 1 0,...,N202 - 1 0,1 +¾ ’*l,2+^2’4 1 y / vi vi' ' vt" "» Vi” Vi” w (7) 1 / ,m i,m I ,m I I ,m I .m / .m yy 11' i" i'h >a nt — i where V7Pcsi-rs -V... -V / WJ

[0053] An issue of indicating the selected beams by using a combinatorial indication, as 5 proposed in Scheme 2 above for ranks 5 to 8, and as is done, for example, for Type-II codebooks is that the beam indication indicates an unordered combination of 2, 3 or 4 beams. In practice, the beam indices are encoded in the combinatorial indicator in an order of increasing index. Therefore, when two codewords are reported, it is not possible to ensure that the conditions above are satisfied to maximize the CQI of the first codeword. 10 For example, it may happen that the strongest beam is the beam with the largest index. Hence, for a rank 5 CSI report, it will be mapped to a single layer (e.g., the fifth layer) and to the second codeword.

[0054] Example embodiments of the present disclosure propose a solution for a codeword based beam indication. In this solution, a plurality of groups of beams are 15 mapped by a first apparatus to a plurality of data blocks (for example, transport blocks or TBs) which are to be received from a second apparatus. Each group of the plurality of groups of beams are mapped to one of the plurality of data blocks. A plurality of separate beam indicators are transmitted to the second apparatus by the first apparatus. Each of the plurality of separate beam indicators indicates a group of the plurality of groups of beams.

[0055] With the proposed solution, the selected beams are reported in separate beam indicators. In this way, certain beams are mapped to certain data blocks and the association is not random, thereby avoiding performance degradation.

[0056] FIG. 1 illustrates an example communication environment 100 in which example embodiments of the present disclosure can be implemented.

[0057] The communication environment 100 comprises a first apparatus 110 which may operate as a terminal device such as a UE. The first apparatus 110 may communicate with a second apparatus 120 which may operate as a network device such as a gNB.

[0058] In some example embodiments, a link from the second apparatus 120 to the first apparatus 110 may be referred to as a downlink, and a link from the first apparatus 110 to the second apparatus 120 is referred to as an uplink. In DL, the second apparatus 120 is a transmitting (TX) device (or a transmitter) and the first apparatus 110 is a receiving (RX) device (or a receiver). In UL, the first apparatus 110 is a TX device (or a transmitter) and the second apparatus 120 is a RX device (or a receiver).

[0059] It is to be understood that the number and types of apparatuses are shown in FIG. 1 for the purpose of illustration without suggesting any limitation. For example, the communication environment 100 may comprise any number and type of apparatuses.

[0060] In the following, for the purpose of illustration, some example embodiments are described with the first apparatus 110 operating as a terminal device and the second apparatus 120 operating as a network device. However, in some example embodiments, operations described with respect to a terminal device may be implemented at a network device or other devices, and operations described with respect to a network device may be implemented at a terminal device or other devices.

[0061] Communications in the communication environment 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G), the sixth generation (6G), and the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0062] In the communication environment 100, a plurality of separate beam indicators may be transmitted by the first apparatus 110 to the second apparatus where each of the separate beam indicators indicates a group of beams for a data block which may be corresponding to a codeword. For example, two separate beam indicators may be employed, one for each of two codewords (corresponding to two data blocks). The number of beams reported in each indicator may depend on the assumed beam-to-layer mapping and layer-to-codeword mapping. Some example implementations will be described below with reference to FIGS. 2 to 5.

[0063] FIG. 2 illustrates a signaling diagram 200 for codeword based beam indication according to some example embodiments of the present disclosure. The signaling diagram 200 involves the first apparatus 110 and the second apparatus 120 in FIG. 1.

[0064] In operation, the first apparatus 110 maps (205) a plurality of groups of beams to a plurality of data blocks. The plurality of data blocks are to be received from the second apparatus 120, and each group of the plurality of groups of beams are mapped to one of the plurality of data blocks. In some example embodiments, the data block may be corresponding to a codework.

[0065] In some example embodiments, the first apparatus 110 map perform one or more measurements of a reference signal from the second apparatus 120 and determine measured strength of a plurality of beams, based on the one or more measurements of the reference signal. The first apparatus 110 may know the strength of beams through its measurements and thus the first apparatus 110 may be able to determine which beams are to be indicated by a certain beam indicator.

[0066] After determining the measured strength of the plurality of beams, the first apparatus 110 may select, from the plurality of beams, one or more beams to be included in a group of the plurality of beams, in a descent order of the measured strength of the plurality of beams. In this way, by selecting beams in a descent order of the strength, it possible to map a first beam (e.g., the strongest beam) to a specific layers or pair of layers and a second beam (e.g., the second strongest beam) to another pair of layers, thereby improving data transmission performance and enchaining throughput.

[0067] After the mapping, the first apparatus 110 transmits (210), to the second apparatus 120, a plurality of separate beam indicators. Correspondingly, the second apparatus 120 receives (215) the plurality of separate beam indicators. Each of the plurality of separate beam indicators indicates a group of the plurality of groups of beams where each group of the plurality of groups of beams are mapped to one of a plurality of data blocks to be transmitted to the first apparatus 110.

[0068] In some example embodiments, a beam with strongest measured strength may be included in a first group of the plurality of groups of the beams. FIG. 3A illustrates an example diagram 300A of an association between beams and codewords for rank 5. As illustrated in FIG. 3A, beam 1 305 is the beam with strongest measured strength which is included in a group of beams 310. A beam indicator 335 for codeword 1 315 indicates beam 1 305, e.g., by a combination of X candidate beams which choose one beams, i.e., beam 1 305. The notation X choose 1 represents the mathematical operation of binomial, also denoted as j = X, which gives the number of possible combinations of one beam out of X. A beam indicator 337 for codeword 2 317 indicates beam 2 307 and beam 3 309, e.g., by a combination of X-l candidate beams which choose 2 beams, i.e., beam 2 307 and beam 3 309. Because one beam from the set X was selected as the first beam for codeword 1, there are X-l remaining beams where to choose the two beams for codeword 2. Hence the number of combinations of two beams from the set of size X-l is given by fX — 1\ the binomial operation: J. Because the beam with strongest measured strength is assigned to codeword 1315, the CQI for codeword 1315 may be maximized.

[0069] In some example embodiments, the plurality of separate beam indicators may be transmitted by the first apparatus 110 to the second apparatus 120 in a report of channel state information (CSI) associated with the plurality of data blocks. Correspondingly, the plurality of separate beam indicators may be received by the second apparatus 120 from the first apparatus 110 in the report of CSI. Channel state information (CSI) associated with each of the plurality of data blocks may be determined on a group of the plurality of beams corresponding to the data block. By way of example, the CSI may include one or more of rank indicator (RI), precoder matric indicator (PMI) and channel quality indicator (CQI). In some example embodiments, the first apparatus 110 may calculate CQI based on the separate beam indicators because CQI is calculated per codeword. The first apparatus 110 may report CSI including precoding weights for layers (e.g., layers 1, 2, 3, 4 and 5 in rank 5) in a format specified by a codebook. As part of that, CSI reporting may include the beam indication of the selected beams for layers.

[0070] In some example embodiments, the number of beams in a group of the plurality of groups of beams may depend on at least one of first mapping of the plurality of groups of beams to a plurality of transmission layers associated with the plurality of data blocks (corresponding to codewords), or second mapping of the plurality of transmission layers to the plurality of data blocks. Still referring to FIG. 3 A, a layer-to-codeword mapping (as an example of the second mapping) 320 combined with beam-to-layer mapping (as an example of the first mapping) 325 may produce a beam to codeword mapping. The number of beams in the group 310 is 1 based on the first mapping and the second mapping. The number of beams in a group of beams 330 is 2 based on the first mapping and the second mapping.

[0071] FIGS. 3B and 3C illustrate example diagrams 300B and 300C of associations between beams and codewords for rank 7 and rank 8, respectively, according to some example embodiments of the present disclosure. As illustrated in FIG. 3B, the number of beams in a group 340 is 2 based on the first mapping and the second mapping. The number of beams in a group 350 is 2 based on the first mapping and the second mapping. As illustrated in FIG. 3C, the number of beams in a group 360 is 2 based on the first mapping and the second mapping. The number of beams in a group 370 is 2 based on the first mapping and the second mapping.

[0072] In some example embodiments, at least two groups of beams among the plurality of groups of beams may include at least one common beam. The common beam will be described with reference to FIG. 4, which illustrates an example diagram 400 of an association between beam and codeword for rank 6. It is to be noted that for rank 6 only 3 beams are selected, and layers are split equally between the two codewords. Accordingly, beam 2 415 supports one layer in codeword 1 430 and one layer in codeword 2 435. As illustrated in FIG. 4, a group 405 and a group 410 share a common beam (e.g., beam 2 415). The beam 2 415 is used to transport the layer 3 420 and the layer 4 425. The layer 3 420 is mapped to codeword 1 430 and the layer 4 425 is mapped to codeword 2 435.

[0073] In some example embodiments, a beam indicator of the plurality of separate beam indicators corresponding to a group of the at least two groups of beams indicates the group of the at least two groups of beams including the at least one common beam, and a further beam indicator of the plurality of separate beam indicators corresponding to a further group of the at least two groups of beams indicates the further group of the at least two groups of beams excluding the at least one common beam. The at least one common beam does not need to be indicated twice as it is indicated in a first beam indicator and the common beam is already known from the first beam indicator. Still referring to FIG. 4, a beam indicator 440 for codeword 1 430 may be a combinatorial indication of X candidate beams that choose 2 beams, e.g., beam 1 450 and beam 2 415 (where beam 2 415 is a common beam of the group 405 and the group 410). The notation X choose 2 represents the mathematical operation of binomial, also denoted as , which gives the number of possible combinations of two beams out of X. A beam indicator 445 for codeword 2 435 may be a combinatorial indication of X-2 candidate beams that choose 1 beam, e.g., beam 3 455.

[0074] After receiving the plurality of separate beam indicators, the second apparatus 120 performs (220) precoding for the plurality of data blocks, based on the plurality of separate beam indicators. The second apparatus 120 may use the separate beam indicator (indicating the association between data block and beam) to reconstruct a precoding matrix.

[0075] An example process of data block based beam indication will be described in detail below with reference to FIG. 5.

[0076] FIG. 5 illustrates an example process 500 of data block based beam indication in accordance with some example embodiments of the present disclosure. In this example, a UE 510 operates as an example implementation of the first apparatus 110 and a gNB 520 operates as an example implementation of the second apparatus 120. The process 500 is illustrated using the proposed data block-specific spatial domain vector grouping and indications.

[0077] As shown in FIG. 5, in the process 500, at 522, the UE 510 sends a UE capability indication of supporting two codewords on PDSCH to the gNB 520. At 524, the gNB 520 configure or trigger or activate CSI reporting to the UE 510.

[0078] At 526, the gNB 520 transmits CSI-RS resource(s) to the UE 510. At 528, the UE 510 calculates CSI, including RI, PMI and CQI by dividing the selected spatial domain (SD) vectors (which may indicate beams) in two groups and mapping layers of the first codeword (corresponding to the first data block) to the SD vectors of the first group and layers of the second codeword (corresponding to the second data block) to SD vectors of the second group.

[0079] At 530, the UE 510 reports CSI containing separate SD vector indicators for each codewords. At 532, the gNB 520 reconstructs precoding matrices by mapping the SD vectors of the first indicator to the layers of the first codeword and the SD vectors of the second indicator to the layers of the second codeword.

[0080] FIG. 6 shows a flowchart of an example method 600 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0081] At block 610, the first apparatus 110 maps a plurality of groups of beams to a plurality of data blocks, where the plurality of data blocks are to be received from a second apparatus, and each group of the plurality of groups of beams are mapped to one of the plurality of data blocks.

[0082] At block 620, the first apparatus 110 transmits, to the second apparatus, a plurality of separate beam indicators, each of the plurality of separate beam indicators indicating a group of the plurality of groups of beams.

[0083] In some example embodiments, the method 600 further comprises: performing one or more measurements of a reference signal from the second apparatus; determine measured strength of a plurality of beams, based on the one or more measurements of the reference signal; and select, from the plurality of beams, one or more beams to be included in a group of the plurality of beams, in a descent order of the measured strength of the plurality of beams.

[0084] In some example embodiments, a beam with strongest measured strength is included in a first group of the plurality of groups of the beams.

[0085] In some example embodiments, the plurality of separate beam indicators is transmitted to the second apparatus in a report of channel state information associated with the plurality of data blocks, and channel state information associated with each of the plurality of data blocks is determined on a group of the plurality of beams corresponding to the data block.

[0086] In some example embodiments, a number of beams in a group of the plurality of groups of beams depends on at least one of: first mapping of the plurality of groups of beams to a plurality of transmission layers associated with the plurality of data blocks, or second mapping of the plurality of transmission layers to the plurality of data blocks.

[0087] In some example embodiments, at least two groups of beams among the plurality of groups of beams include at least one common beam.

[0088] In some example embodiments, a beam indicator of the plurality of separate beam indicators corresponding to a group of the at least two groups of beams indicates the group of the at least two groups of beams including the at least one common beam, and a further beam indicator of the plurality of separate beam indicators corresponding to a further group of the at least two groups of beams indicates the further group of the at least two groups of beams excluding the at least one common beam.

[0089] FIG. 7 shows a flowchart of an example method 700 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0090] At block 710, the second apparatus 120 receives, from a first apparatus, a plurality of separate beam indicators, where each of the plurality of separate beam indicators indicates a group of the plurality of groups of beams, and each group of the plurality of groups of beams are mapped to one of a plurality of data blocks to be transmitted to the first apparatus.

[0091] At block 720, the second apparatus 120 performs precoding for the plurality of data blocks, based on the plurality of separate beam indicators.

[0092] In some example embodiments, a beam with strongest measured strength is included in a first group of the plurality of groups of the beams.

[0093] In some example embodiments, the plurality of separate beam indicators is received from the first apparatus in a report of channel state information associated with the plurality of data blocks, and channel state information associated with each of the plurality of data blocks is determined on a group of the plurality of beams corresponding to the data block.

[0094] In some example embodiments, a number of beams in a group of the plurality of groups of beams depends on at least one of first mapping of the plurality of groups of beams to a plurality of transmission layers associated with the plurality of data blocks, or second mapping of the plurality of transmission layers to the plurality of data blocks.

[0095] In some example embodiments, at least two groups of beams among the plurality of groups of beams include at least one common beam.

[0096] In some example embodiments, a beam indicator of the plurality of separate beam indicators corresponding to a group of the at least two groups of beams indicates the group of the at least two groups of beams including the at least one common beam, and a further beam indicator of the plurality of separate beam indicators corresponding to a further group of the at least two groups of beams indicates the further group of the at least two groups of beams excluding the at least one common beam.

[0097] In some example embodiments, a first apparatus capable of performing any of the method 600 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1.

[0098] In some example embodiments, the first apparatus comprises means for mapping a plurality of groups of beams to a plurality of data blocks, where the plurality of data blocks are to be received from a second apparatus, and each group of the plurality of groups of beams are mapped to one of the plurality of data blocks; and means for transmitting, to the second apparatus, a plurality of separate beam indicators, each of the plurality of separate beam indicators indicating a group of the plurality of groups of beams.

[0099] In some example embodiments, the first apparatus further comprises means for performing one or more measurements of a reference signal from the second apparatus; means for determining measured strength of a plurality of beams, based on the one or more measurements of the reference signal; and means for selecting, from the plurality of beams, one or more beams to be included in a group of the plurality of beams, in a descent order of the measured strength of the plurality of beams.

[0100] In some example embodiments, a beam with strongest measured strength is included in a first group of the plurality of groups of the beams.

[0101] In some example embodiments, the plurality of separate beam indicators is transmitted to the second apparatus in a report of channel state information associated with the plurality of data blocks, and channel state information associated with each of the plurality of data blocks is determined on a group of the plurality of beams corresponding to the data block.

[0102] In some example embodiments, a number of beams in a group of the plurality of groups of beams depends on at least one of: first mapping of the plurality of groups of beams to a plurality of transmission layers associated with the plurality of data blocks, or second mapping of the plurality of transmission layers to the plurality of data blocks.

[0103] In some example embodiments, at least two groups of beams among the plurality of groups of beams include at least one common beam.

[0104] In some example embodiments, a beam indicator of the plurality of separate beam indicators corresponding to a group of the at least two groups of beams indicates the group of the at least two groups of beams including the at least one common beam, and a further beam indicator of the plurality of separate beam indicators corresponding to a further group of the at least two groups of beams indicates the further group of the at least two groups of beams excluding the at least one common beam.

[0105] In some example embodiments, a second apparatus capable of performing any of the method 700 (for example, the second apparatus 120 in FIG. 1) may comprise means for performing the respective operations of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0106] In some example embodiments, the second apparatus comprises means for receiving, from a first apparatus, a plurality of separate beam indicators, where each of the plurality of separate beam indicators indicates a group of the plurality of groups of beams, and each group of the plurality of groups of beams are mapped to one of a plurality of data blocks to be transmitted to the first apparatus; and means for performing precoding for the plurality of data blocks, based on the plurality of separate beam indicators.

[0107] In some example embodiments, a beam with strongest measured strength is included in a first group of the plurality of groups of the beams.

[0108] In some example embodiments, the plurality of separate beam indicators is received from the first apparatus in a report of channel state information associated with the plurality of data blocks, and channel state information associated with each of the plurality of data blocks is determined on a group of the plurality of beams corresponding to the data block.

[0109] In some example embodiments, a number of beams in a group of the plurality of groups of beams depends on at least one of: first mapping of the plurality of groups of beams to a plurality of transmission layers associated with the plurality of data blocks, or second mapping of the plurality of transmission layers to the plurality of data blocks.

[0110] In some example embodiments, at least two groups of beams among the plurality of groups of beams include at least one common beam.

[0111] In some example embodiments, a beam indicator of the plurality of separate beam indicators corresponding to a group of the at least two groups of beams indicates the group of the at least two groups of beams including the at least one common beam, and a further beam indicator of the plurality of separate beam indicators corresponding to a further group of the at least two groups of beams indicates the further group of the at least two groups of beams excluding the at least one common beam.

[0112] FIG. 8 is a simplified block diagram of a device 800 that is suitable for implementing example embodiments of the present disclosure. The device 800 may be provided to implement a communication device, for example, the first apparatus 110 or the second apparatus 120 as shown in FIG. 1. As shown, the device 800 includes one or more processors 810, one or more memories 820 coupled to the processor 810, and one or more communication modules 840 coupled to the processor 810.

[0113] The communication module 840 is for bidirectional communications. The communication module 840 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interfaces may represent any interface that is necessary for communication with other network elements. In some example embodiments, the communication module 840 may include at least one antenna.

[0114] The processor 810 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 800 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0115] The memory 820 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 824, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), an optical disk, a laser disk, and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random-access memory (RAM) 822 and other volatile memories that will not last in the power-down duration.

[0116] A computer program 830 includes computer executable instructions that are executed by the associated processor 810. The instructions of the program 830 may include instructions for performing operations / acts of some example embodiments of the present disclosure. The program 830 may be stored in the memory, e.g., the ROM 824. The processor 810 may perform any suitable actions and processing by loading the program 830 into the RAM 822.

[0117] The example embodiments of the present disclosure may be implemented by means of the program 830 so that the device 800 may perform any process of the disclosure as discussed with reference to FIG. 2 to FIG. 7. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0118] In some example embodiments, the program 830 may be tangibly contained in a computer readable medium which may be included in the device 800 (such as in the memory 820) or other storage devices that are accessible by the device 800. The device 800 may load the program 830 from the computer readable medium to the RAM 822 for execution. In some example embodiments, the computer readable medium may include any types of non-transitory storage medium, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e g., RAM vs. ROM).

[0119] FIG. 9 shows an example of the computer readable medium 900 which may be in form of CD, DVD or other optical storage disk. The computer readable medium 900 has the program 830 stored thereon.

[0120] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, and other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. Although various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0121] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer readable medium, such as a non-transitory computer readable medium. The computer program product includes computerexecutable instructions, such as those included in program modules, being executed in a device on a target physical or virtual processor, to carry out any of the methods as described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0122] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general-purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0123] In the context of the present disclosure, the computer program code or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0124] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random-access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0125] Further, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, although several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the 5 present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Unless explicitly stated, certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated, various features that are described in the context of a single embodiment may also be implemented in a plurality of embodiments separately 10 or in any suitable sub-combination.

[0126] Although the present disclosure has been described in languages specific to structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are 15 disclosed as example forms of implementing the claims.

Claims

1. A first apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to:map a plurality of groups of beams to a plurality of data blocks, wherein the plurality of data blocks are to be received from a second apparatus, and each group of the plurality of groups of beams are mapped to one of the plurality of data blocks; andtransmit, to the second apparatus, a plurality of separate beam indicators, each of the plurality of separate beam indicators indicating a group of the plurality of groups of beams.

2. The first apparatus of claim 1, wherein the at least one memory and the at least one processor further cause the first apparatus to:perform one or more measurements of a reference signal from the second apparatus;determine measured strength of a plurality of beams, based on the one or more measurements of the reference signal; andselect, from the plurality of beams, one or more beams to be included in a group of the plurality of beams, in a descent order of the measured strength of the plurality of beams.

3. The first apparatus of claim 2, wherein a beam with strongest measured strength is included in a first group of the plurality of groups of the beams.

4. The first apparatus of claim 2 or 3, wherein the plurality of separate beam indicators is transmitted to the second apparatus in a report of channel state information associated with the plurality of data blocks, and channel state information associated with each of the plurality of data blocks is determined on a group of the plurality of beams corresponding to the data block.

5. The first apparatus of any of claims 1 to 4, wherein a number of beams in a group of the plurality of groups of beams depends on at least one of: first mapping of theplurality of groups of beams to a plurality of transmission layers associated with the plurality of data blocks, or second mapping of the plurality of transmission layers to the plurality of data blocks.

6. The first apparatus of any of claims 1 to 5, wherein at least two groups of beams among the plurality of groups of beams include at least one common beam.

7. The first apparatus of claim 6, wherein a beam indicator of the plurality of separate beam indicators corresponding to a group of the at least two groups of beams indicates the group of the at least two groups of beams including the at least one common beam, and a further beam indicator of the plurality of separate beam indicators corresponding to a further group of the at least two groups of beams indicates the further group of the at least two groups of beams excluding the at least one common beam.

8. A second apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to:receive, from a first apparatus, a plurality of separate beam indicators, wherein each of the plurality of separate beam indicators indicates a group of the plurality of groups of beams, and each group of the plurality of groups of beams are mapped to one of a plurality of data blocks to be transmitted to the first apparatus; andperform precoding for the plurality of data blocks, based on the plurality of separate beam indicators.

9. The second apparatus of claim 8, wherein a beam with strongest measured strength is included in a first group of the plurality of groups of the beams.

10. The second apparatus of claim 8 or 9, wherein the plurality of separate beam indicators is received from the first apparatus in a report of channel state information associated with the plurality of data blocks, and channel state information associated with each of the plurality of data blocks is determined on a group of the plurality of beams corresponding to the data block.

11. The second apparatus of any of claims 8 to 10, wherein a number of beams in a group of the plurality of groups of beams depends on at least one of: first mapping of the plurality of groups of beams to a plurality of transmission layers associated with the plurality of data blocks, or second mapping of the plurality of transmission layers to the plurality of data blocks.

12. The second apparatus of any of claims 8 to 11, wherein at least two groups of beams among the plurality of groups of beams include at least one common beam.

13. The second apparatus of claim 12, wherein a beam indicator of the plurality of separate beam indicators corresponding to a group of the at least two groups of beams indicates the group of the at least two groups of beams including the at least one common beam, and a further beam indicator of the plurality of separate beam indicators corresponding to a further group of the at least two groups of beams indicates the further group of the at least two groups of beams excluding the at least one common beam.

14. A method comprising:mapping a plurality of groups of beams to a plurality of data blocks, wherein the plurality of data blocks are to be received from a second apparatus, and each group of the plurality of groups of beams are mapped to one of the plurality of data blocks.transmitting, to the second apparatus, a plurality of separate beam indicators, each of the plurality of separate beam indicators indicating a group of the plurality of groups of beams.

15. A method comprising:receiving, from a first apparatus, a plurality of separate beam indicators, wherein each of the plurality of separate beam indicators indicates a group of the plurality of groups of beams, and each group of the plurality of groups of beams are mapped to one of a plurality of data blocks to be transmitted to the first apparatus.performing precoding for the plurality of data blocks, based on the plurality of separate beam indicators.

16. A first apparatus comprising:means for mapping a plurality of groups of beams to a plurality of data blocks, wherein the plurality of data blocks are to be received from a second apparatus, and each group of the plurality of groups of beams are mapped to one of the plurality of data blocks; andmeans for transmitting, to the second apparatus, a plurality of separate beam indicators, each of the plurality of separate beam indicators indicating a group of the plurality of groups of beams.

17. A second apparatus comprising:means for receiving, from a first apparatus, a plurality of separate beam indicators, wherein each of the plurality of separate beam indicators indicates a group of the plurality of groups of beams, and each group of the plurality of groups of beams are mapped to one of a plurality of data blocks to be transmitted to the first apparatus; andmeans for performing precoding for the plurality of data blocks, based on the plurality of separate beam indicators.

18. A computer readable medium comprising instructions stored thereon for causing an apparatus at least to perform the method of claim 14 or the method of claim 15.

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