Adjusting transmission powers of layers

Abstract

Various examples of the disclosure provide an apparatus (10, 110) comprising: at least one processor (12); and at least one memory (13) including computer program code (14), the at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform at least the following: receiving (501) at least one precoded reference signal (502) from a node of a Radio Access Network, RAN (120); determining (503), based at least in part on the at least one precoded reference signal: a plurality of precoded layers (504) of a channel, and first information (505) indicative of at least one power adjustment (506) for at least one precoded layer of the plurality of precoded layers of the channel; and transmitting (507) the first information to the node of the RAN.

Description

TITLEADJUSTING TRANSMISSION POWERS OF LAYERSTECHNOLOGICAL FIELD

[0001] Certain examples of the disclosure relate to apparatuses, methods, and computer programs for adjusting transmission powers of layers. Certain examples of the disclosure relate to apparatuses, methods, and computer programs for adjusting transmission powers of Multiple Input Multiple Output, MIMO, layers.BACKGROUND

[0002] Conventional apparatuses and procedures for adjusting transmission powers of layer, e.g. adjusting transmission powers of MIMO layers, are not always optimal.

[0003] In some circumstances, it may be desirable to improve adjustment of transmission powers for layers. In some circumstances, it may be desirable to provide improved apparatuses, method and computer programs for adjusting transmission powers for layers. In some circumstances, it may be desirable to provide improved feedback information for assisting a Base Station, BS, to adjust layer transmission powers. In some circumstances, it may be desirable to provide a procedure and signaling for providing improved feedback information for assisting a BS to adjust layer transmission powers.

[0004] The listing or discussion of any prior-published document or any background in this specification should not necessarily be taken as an acknowledgement that the document or background is part of the state of the art or is common general knowledge. One or more aspects / examples of the present disclosure may or may not address one or more of the background issues.BRIEF SUMMARY

[0005] The invention is defined in the independent claims.

[0006] According to various, but not necessarily all, examples of the disclosure there are provided examples as claimed in the appended claims. Any examples and features described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention.

[0007] According to various, but not necessarily all, examples of the disclosure there is provided a method comprising: receiving, at an apparatus, at least one reference signal from a node of a Radio Access Network, RAN; determining, at the apparatus, based at least in part on the at least one reference signal: a plurality of precoded layers of a channel, and first information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers; and transmitting, from the apparatus to the node of the RAN, the first information.

[0008] According to various, but not necessarily all, embodiments there is provided an apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform the above-mentioned method.

[0009] According to various, but not necessarily all, examples of the disclosure there is provided a non-transitory computer readable medium encoded with instructions that, when executed by at least one processor, causes the apparatus to perform the above-mentioned method.

[0010] According to at least some examples of the disclosure there is provided an apparatus comprising means for perform the above-mentioned method.

[0011] According to various, but not necessarily all, examples of the disclosure there is provided a computer program comprising instructions, which when executed by an apparatus, cause the apparatus to perform the above-mentioned method.

[0012] The following portion of this ‘Brief Summary’ section describes various features that can be features of any of the examples described in the foregoing portion of the ‘Brief Summary’ section mutatis mutandis. The description of a function should additionally be considered to also disclose any means suitable for performing that function, or any instructions stored in at least one memory that, when executed by at least one processor, cause an apparatus to perform that function.

[0013] In some but not necessarily all examples, the method further comprises: determining, based at least in part on the at least one reference signal, one or more components of channel state information, CSI; wherein the determining, based at least in part on the at least one reference signal, the plurality of precoded layers of the channel further comprises determining the plurality of precoded layers based at least in part on at least one of the one or more components of CSI; and wherein the determining, based at least in part on the at least one reference signal, the first information further comprises determining the first information based at least in part on at least one of the one or more components of CSI.

[0014] In some but not necessarily all examples, the determining, based at least in part on the at least one reference signal, the first information further comprises determining the first information based at least in part on at least one of the following: a number of the plurality of precoded layers, wherein the number of the plurality of precoded layers is determined based at least in part on at least one of the one or more components of the CSI; or a precoding for the plurality of precoded layers, wherein the precoding is determined based at least in part on at least one of the one or more components of the CSI.

[0015] In some but not necessarily all examples, the first information is further indicative of at least one of the following: at least one power adjustment expected to be required for at least one precoded layer of a plurality of precoded layers expected to be transmitted by the node of the RAN; a power adjustment for each precoded layer of the plurality of precoded layers; or at least a first power adjustment of at least a first precoded layer of the plurality of precoded layers wherein the first power adjustment is relative to a power of at least a second precoded layer of the plurality of precoded layers.

[0016] In some but not necessarily all examples, the first information further comprises an identification of which precoded layers of the plurality of precoded layers require power adjustment.

[0017] In some but not necessarily all examples, the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a power adjustment is estimated to be required for the respective precoded layer represented by the respective bit.

[0018] In some but not necessarily all examples, the first information further comprises an indication of a plurality of power adjustment amounts estimated to be required for the plurality of precoded layers.

[0019] In some but not necessarily all examples, the first information further comprises an indication of a quality metric for one of the plurality of precoded layers relative to at least one of a first quality metric reported, by the apparatus, to the node of the RAN; a second quality metric for another of the plurality of precoded layers; or a third quality metric for a successive precoded layer of the plurality of precoded layers.

[0020] In some but not necessarily all examples, the first information further comprises an indication of an estimated power adjustment amount for one of the plurality of precoded layers relative to another of the plurality of precoded layers.

[0021] In some but not necessarily all examples, the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of multiple precoded layers of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a power adjustment is estimated to be required for the respective multiple precoded layers represented by the respective bit.

[0022] In some but not necessarily all examples, the first information further comprises an indication of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold power.

[0023] In some but not necessarily all examples, the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein avalue of each bit of the bitmap is representative of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold.

[0024] In some but not necessarily all examples, the first information further comprises an indication of a quality metric for the plurality of precoded layers that meet the threshold power relative to a quality metric for all of the plurality of precoded layers.

[0025] In some but not necessarily all examples, the first information further comprises an indication of a quality metric for the plurality of precoded layers that do not meet the threshold power relative to a quality metric for all of the plurality of precoded layers.

[0026] In some but not necessarily all examples, the plurality of precoded layers represented by the bitmap correspond to: a plurality of precoded layers that would be formed based on a Rank Indicator, RI, and a Precoder Matrix Indicator, PMI, determined by the apparatus and reported to the node of the RAN.

[0027] According to various, but not necessarily all, examples of the disclosure there is provided a method comprising: receiving, at an apparatus, at least one precoded reference signal from a node of a Radio Access Network, RAN; determining, at the apparatus, based at least in part on the at least one precoded reference signal: a plurality of precoded layers of a channel, and first information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers of the channel; and transmitting, from the apparatus to the node of the RAN, the first information.

[0028] According to various, but not necessarily all, embodiments there is provided an apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform the above-mentioned method.

[0029] According to various, but not necessarily all, examples of the disclosure there is provided a non-transitory computer readable medium encoded with instructions that, when executed by at least one processor, causes the apparatus to perform the above-mentioned method.

[0030] According to at least some examples of the disclosure there is provided an apparatus comprising means for perform the above-mentioned method.

[0031] According to various, but not necessarily all, examples of the disclosure there is provided a computer program comprising instructions, which when executed by an apparatus, cause the apparatus to perform the above-mentioned method.

[0032] The following portion of this ‘Brief Summary’ section describes various features that can be features of any of the examples described in the foregoing portion of the ‘Brief Summary’ section mutatis mutandis. The description of a function should additionally be considered to also disclose any means suitable for performing that function, or any instructions stored in at least one memory that, when executed by at least one processor, cause an apparatus to perform that function.

[0033] In some but not necessarily all examples, the at least one precoded reference signal has the same precoding as the precoding of the plurality of precoded layers of the channel, and wherein the determining, based at least in part on the at least one precoded reference signal, the plurality of precoded layers of the channel further comprises determining theplurality of precoded layers based at least in part on the precoding of the at least one precoded reference signal.

[0034] In some but not necessarily all examples, the at least one precoded reference signal is transmitted by the node of the RAN over a plurality of antenna ports; wherein each of the plurality of antenna ports is mapped to a precoded layer of the plurality of precoded layers of the channel; and wherein the determining, based at least in part on the at least one precoded reference signal, the plurality of precoded layers of the channel further comprises determining the plurality of precoded layers based at least in part on the mapping of the plurality of antenna ports to the plurality of precoded layers of the channel.

[0035] In some but not necessarily all examples, the method further comprises: receiving, from the node of the RAN, at least one second reference signal for estimating a condition of a radio channel; determining, based at least in part on the at least one second reference signal, at least one of the following: one or more components of channel state information, CSI; or second information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers; transmitting, to the node of the RAN, at least one of the following: the one or more components of the CSI, or the second information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers; and wherein, the at least one precoded reference signal is precoded by the node of the RAN based at least in part on at least one of the following: the one or more components of the CSI transmitted to the node of the RAN; or the second information transmitted to the node of the RAN.

[0036] In some but not necessarily all examples, the first information is further indicative of at least one of the following: at least one power adjustment expected to be required for at least one precoded layer of a plurality of precoded layers expected to be transmitted by the node of the RAN; a power adjustment for each precoded layer of the plurality of precoded layers; or at least a first power adjustment of at least a first precoded layer of the plurality precoded layers wherein the first power adjustment is relative to a power of at least a second precoded layer of the plurality of precoded layers.

[0037] In some but not necessarily all examples, the first information further comprises an identification of which precoded layers of the plurality of precoded layers require power adjustment.

[0038] In some but not necessarily all examples, the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a power adjustment is estimated to be required for the respective precoded layer represented by the respective bit.

[0039] In some but not necessarily all examples, the first information further comprises an indication of a plurality of power adjustment amounts estimated to be required for the plurality of precoded layers.

[0040] In some but not necessarily all examples, the first information further comprises an indication of a quality metric for one of the plurality of precoded layers relative to at least one of a first quality metric reported, by the apparatus, to the node of the RAN; a second quality metric for another of the plurality of precoded layers; ora third quality metric for a successive precoded layer of the plurality of precoded layers.

[0041] In some but not necessarily all examples, the first information further comprises an indication of an estimated power adjustment amount for one of the plurality of precoded layers relative to another of the plurality of precoded layers.

[0042] In some but not necessarily all examples, the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of multiple precoded layers of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a power adjustment is estimated to be required for the respective multiple precoded layers represented by the respective bit.

[0043] In some but not necessarily all examples, the first information further comprises an identification of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold power.

[0044] In some but not necessarily all examples, the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold.

[0045] In some but not necessarily all examples, the first information further comprises an indication of a quality metric for the plurality of precoded layers that meet the threshold power relative to a quality metric for all of the plurality of precoded layers.

[0046] In some but not necessarily all examples, the first information further comprises an indication of a quality metric for the plurality of precoded layers that do not meet the threshold power relative to a quality metric for all of the plurality of precoded layers.

[0047] In some but not necessarily all examples, the plurality of precoded layers represented by the bitmap correspond to: a plurality of ports used, by the node of the RAN, in transmitting the at least one precoded reference signal.

[0048] According to various, but not necessarily all, examples of the disclosure there is provided a method comprising: receiving, at an apparatus over a plurality of precoded layers of a channel, at least one reference signal from a node of a Radio Access Network, RAN; determining, at the apparatus, based at least in part on the at least one reference signal, first information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers; and transmitting, from the apparatus to the node of the RAN, the first information.

[0049] According to various, but not necessarily all, embodiments there is provided an apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform the above-mentioned method.

[0050] According to various, but not necessarily all, examples of the disclosure there is provided a non-transitory computer readable medium encoded with instructions that, when executed by at least one processor, causes the apparatus to perform the above-mentioned method.

[0051] According to at least some examples of the disclosure there is provided an apparatus comprising means for perform the above-mentioned method.

[0052] According to various, but not necessarily all, examples of the disclosure there is provided a computer program comprising instructions, which when executed by an apparatus, cause the apparatus to perform the above-mentioned method.

[0053] The following portion of this ‘Brief Summary’ section describes various features that can be features of any of the examples described in the foregoing portion of the ‘Brief Summary’ section mutatis mutandis. The description of a function should additionally be considered to also disclose any means suitable for performing that function, or any instructions stored in at least one memory that, when executed by at least one processor, cause an apparatus to perform that function.

[0054] In some but not necessarily all examples, the method further comprises: receiving, from the node of the RAN, at least one reference signal; determining, based at least in part on the at least one reference signal, one or more components of channel state information, CSI; transmitting, to the node of the RAN, the one or more components of the CSI; and wherein, the at least one precoded channel is precoded by the node of the RAN based at least in part on the one or more components of the CSI transmitted to the node of the RAN.

[0055] In some but not necessarily all examples, the first information is further indicative of at least one of the following: at least one power adjustment expected to be required for at least one precoded layer of a plurality of precoded layers expected to be transmitted by the node of the RAN; a power adjustment for each precoded layer of the plurality of precoded layers; or at least a first power adjustment of at least a first precoded layer of the plurality of precoded layers wherein the first power adjustment is relative to a power of at least a second precoded layer of the plurality of precoded layers.

[0056] In some but not necessarily all examples, the first information further comprises an identification of which precoded layers of the plurality of precoded layers require power adjustment.

[0057] In some but not necessarily all examples, the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a power adjustment is estimated to be required for the respective precoded layer represented by the respective bit.

[0058] In some but not necessarily all examples, the first information further comprises an indication of a plurality of power adjustment amounts estimated to be required for the plurality of precoded layers.

[0059] In some but not necessarily all examples, the first information further comprises an indication of a quality metric for one of the plurality of precoded layers relative to at least one of a first quality metric reported, to the node of the RAN; a second quality metric for another of the plurality of precoded layers; or a third quality metric for a successive precoded layer of the plurality of precoded layers.

[0060] In some but not necessarily all examples, the first information further comprises an indication of an estimated power adjustment amount for one of the plurality of precoded layers relative to another of the plurality of precoded layers.

[0061] In some but not necessarily all examples, the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of multiple precoded layers of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a power adjustment is estimated tobe required for the respective multiple precoded layers represented by the respective bit.

[0062] In some but not necessarily all examples, the first information further comprises an identification of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold power.

[0063] In some but not necessarily all examples, the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold.

[0064] In some but not necessarily all examples, the first information further comprises an indication of a quality metric for the plurality of precoded layers that meet the threshold power relative to a quality metric for all of the plurality of precoded layers.

[0065] In some but not necessarily all examples, the first information further comprises an indication of a quality metric for the plurality of precoded layers that do not meet the threshold power relative to a quality metric for all of the plurality of precoded layers.

[0066] In some but not necessarily all examples, the plurality of precoded layers represented by the bitmap correspond to: the plurality of precoded layers of the precoded channel.

[0067] According to various, but not necessarily all, examples of the disclosure there is provided: an apparatus, a module, circuitry, a chipset comprising processing circuitry, a device and / or a system configured to (or comprising means for) perform(ing) at least a part of one or more methods described herein.

[0068] The description herein of a function and / or action should additionally be considered to also disclose any means suitable for performing that function and / or action. Functions and / or actions described herein can be performed in any suitable way using any suitable method.

[0069] According to various, but not necessarily all, embodiments there are provided examples as claimed in the appended claims.

[0070] While the above examples of the disclosure and optional features are described separately, it is to be understood that their provision in all possible combinations and permutations is contained within the disclosure. It is to be understood that various examples of the disclosure can comprise any or all the features described in respect of other examples of the disclosure, and vice versa. Also, it is to be appreciated that any one or more or all the features, in any combination, may be implemented by / comprised in / performable by an apparatus, a method, and / or computer program instructions as desired, and as appropriate. The description of a function should additionally be considered to also disclose any means suitable for performing that function.BRIEF DESCRIPTION

[0071] Some examples will now be described with reference to the accompanying drawings in which:

[0072] FIG. 1 shows an example of the subject matter described herein;

[0073] FIG. 2 shows another example of the subject matter described herein;

[0074] FIG. 3 shows another example of the subject matter described herein;

[0075] FIG. 4 shows another example of the subject matter described herein;

[0076] FIG. 5 shows another example of the subject matter described herein;

[0077] FIG. 6 shows another example of the subject matter described herein;

[0078] FIG. 7 shows another example of the subject matter described herein;

[0079] FIG. 8 shows another example of the subject matter described herein;

[0080] FIG. 9 shows another example of the subject matter described herein; and

[0081] FIG. 10 shows another example of the subject matter described herein.

[0082] The figures are not necessarily to scale. Certain features and views of the figures can be shown schematically or exaggerated in scale in the interest of clarity and conciseness. For example, the dimensions of some elements in the figures can be exaggerated relative to other elements to aid explication. Similar reference numerals are used in the figures to designate similar features. For clarity, all reference numerals are not necessarily displayed in all figures.

[0083] In the description and drawings, a reference number without a subscript (e.g. 123) can be used as a generic reference to a feature or class / set of features. A reference number with a subscript (e.g. 123 1) can be used as a specific reference, e.g. to differentiate different instances of a feature or class / set of features. The subscript can comprise two digits including a first digit that labels a group of instances and a second digit that labels different instances in the group. A numerical type subscript index (e.g. 123 1) can be used to indicate a specific instance of a class / a member of a set; and a non-specific instance of the class (member of the set) can be referenced using the reference number with a variable type subscript index (e.g. 123_i).ABBREVIATIONS / DEFINITIONS

[0084] BIV Boosting Information Vector

[0085] BS Base Station

[0086] CSI Channel State Information

[0087] CQI Channel Quality Indicator

[0088] CRI CSI-RS Resource Indicator

[0089] DL Downlink

[0090] DM-RS Demodulation Reference Signal

[0091] DSV Delta Signal-to-Interference-plus-Noise Ratio Vector

[0092] gNB Next generation NodeB, 5G / NR base station

[0093] LBB Layer Boosting Bitmap

[0094] LI Layer Indicator

[0095] LQB Layer Quality Bitmap

[0096] MAC CE Medium Access Control Control Element

[0097] MCS Modulation and Coding Scheme

[0098] MIMO Multiple Input Multiple Output

[0099] NW Network

[0100] PDSCH Physical Downlink Shared Channel

[0101] PMI Precoder Matrix Indicator

[0102] RAN Radio Access Network

[0103] RI Rank Indicator

[0104] RRC Radio Resource Control

[0105] RS Reference Signal

[0106] SINR Signal-to-Interference-plus-Noise Ratio

[0107] UE User EquipmentDETAILED DESCRIPTION

[0108] FIG. 1 schematically illustrates an example of a network 100 suitable for use with examples of the present disclosure. The network (which may be referred to as NW) comprises a plurality of network nodes or network entities (each of which may be referred to as NE), including: terminal apparatuses 110 (which may be referred to as terminal nodes or User Equipment, UE); access apparatuses 120 (which may be referred to as access nodes, gNodeBs, gNBs, or Base Stations, BSs);one or more core network apparatuses 130 (which may be referred to as core nodes, core functions, core entities, core network entities).

[0109] The terminal nodes 110 and access nodes 120 communicate with each other. The access nodes 120 communicate with the core nodes 130. The access nodes 120 and LMF 140 may communicate directly with each other. One or more access nodes 120 may, in some but not necessarily all examples, communicate with each other. One or more core network nodes 130 may, in some but not necessarily all examples, communicate with each other.

[0110] The network 100, in the example illustrates in FIG. 1, comprises a radio telecommunications network in which at least some of the terminal nodes 110 and access nodes 120 communicate with each other using transmission / reception of radio waves. In this regard, the network 100 comprises a Radio Access Network, RAN, such as a cellular network comprising a plurality of cells 122 each served by an access node 120. The access nodes 120 comprise cellular radio transceivers. The terminal nodes 110 comprise cellular radio transceivers.

[0111] In the example illustrated and discussed below, the network 100 is a New Radio, NR, network of the Third Generation Partnership Project, 3 GPP, and its fifth generation, 5G, New Radio, NR, technology. It is to be appreciated, however, that in other examples, the network 100 may be a network beyond 5G, for example a next generation (i.e. sixth generation, 6G) Radio Network that is currently under development (i.e. an evolution of the NR network and its 5G technology).

[0112] The interfaces between the terminal nodes 110 and the access nodes 120 are radio interfaces 124 (e.g., Uu interfaces). The interfaces between the access nodes 120 and one or more core nodes 130 are backhaul interfaces 128 (e.g., SI and / or Next Generation, NG, interfaces).

[0113] Depending on the exact deployment scenario, the access nodes 120 may be RAN nodes such as NG-RAN nodes. NG-RAN nodes may be gNodeBs, gNBs, that provide NG user plane and control plane protocol terminations towards the UE. The gNBs are connected by means of NG interfaces to a 5G Core, 5GC, not least for example to an Access and Mobility Management Function, AMF, by means of an NG Control Plane, NG-C, interface and to a User Plane Function, UPF, by means of an NG User Plane, NG-U, interface. The AMF may be connected by means of an N1 interface to the UE (not shown). The access nodes 120 may be interconnected with each other by means of Xn interfaces 126.

[0114] The cellular network 100 may be configured to operate in licensed frequency bands, or unlicensed frequency bands (not least such as: unlicensed bands that rely upon a transmitting device to sense the radio resources / medium before commencing transmission, such as via a Listen Before Talk, LBT, procedure; and a 60GHz unlicensed band where beamforming may be required to achieve required coverage).

[0115] The access nodes 120 may be deployed in an NG standalone operation / scenario. The access nodes 120 may be deployed in a NG non-standalone operation / scenario. The access nodes 120 may be deployed in a Carrier Aggregation, CA, operation / scenario. The access nodes 120 may be deployed in a Dual Connectivity, DC, operation / scenario, i.e., Multi Radio Access Technology - Dual Connectivity, MR-DC, or NR-DC. The access nodes 120 may be deployed in a Multi Connectivity, MC, operation / scenario.

[0116] In such non-standalone / dual connectivity deployments, the access nodes 120 may be interconnected to each other by means of X2 or Xn interfaces, and connected to an Evolved Packet Core, EPC, by means of an SI interface or to the 5GC by means of a NG interface.

[0117] A terminal node 110, in addition to being capable of communicating (i.e. with other terminal nodes) via access nodes 120 of the network 100, may also be capableof and configured to communicate directly with one or more other terminal nodes. In this regard, the terminal node may be capable of and configured to perform device-to- device, D2D, communication - which may be referred to as Sidelink, SL, communication. Such D2D / SL communication may use a PC5 interface. PC5 refers to a reference point where the terminal node communicates directly with another terminal node over a direct channel (i.e. communication via an access node is not required). D2D communications may be short-range, network-less, direct communications. SL in New Radio (NR) is defined in 3GPP’s release 16 of 5GNR.

[0118] In the example of FIG. 1 the core node 130 is shown as a single entity. In some examples the core node 130 could be distributed across a plurality of entities. For example, the core node 130 could be cloud based or distributed in any other suitable manner. The core node / core entities may provide one or more functions, not least such as: User Plane Function UPF, Session Management Function SMF, Policy Control Function PCF, Application Function AF, Location Management Function, LMF, and Access and Mobility Management Function, AMF.

[0119] The access nodes 120 are network elements in the network responsible for radio transmission and reception in one or more cells 122 to or from the terminal nodes 110. The access nodes 120 are the network termination of a radio link. Each access node may be a Transmission Reception Point, TRP, or may host one or more TRPs.

[0120] An access node 120 may be implemented as a single network equipment, or have a split architecture that is disaggregated / distributed over two or more access nodes, such as a Centralized / Control Unit, CU, a Distributed Unit, DU, a Remote Radio Head-end, RRH, using different functional-split architectures and different interfaces.

[0121] The terminal nodes 110 are network elements in the network that terminate the user side of the radio link. They are devices allowing access to network services.Terminal node 110 functionalities may be performed also by Mobile Termination, MT, part of an Integrated Access and Backhaul, IAB, node. The terminal nodes 110 may be referred to as User Equipment, UE, mobile equipment, mobile terminals, or mobile stations.

[0122] The term ‘User Equipment’ may be used to designate mobile equipment comprising means, such as a smart card, for authenticati on / encry ption etc. such as a Subscriber Identity Module, SIM. A SIM / SIM card can be a memory chip, a module, or a Universal Subscriber Identity Module (USIM). In some examples, the term ‘User Equipment’ can be used to designate a location / position tag, a hyper / smart, a hyper / smart sensor, or a mobile equipment comprising circuitry embedded as part of the user equipment for authentication / encryption such as a software SIM.

[0123] In the following description, a terminal node may be referred to simply as UE 110.

[0124] In the following description, an access apparatus / access node to a RAN (e.g. a cellular network not least such as a 5G or 6G next generation RAN) may be referred to interchangeably as BS 120 or gNB 120.

[0125] As will be discussed in further detail below, various examples of the present disclosure relate to adjusting a gNB’s transmit power on layers in a MIMO system.

[0126] FIG. 2 shows an example of a MIMO System in Orthogonal Frequency Division Multiplexing, OFDM. In the example MIMO link shown FIG. 2, two layers are transmitted to a receiver.

[0127] There now follows a brief discussion of the acquisition of Channel State Information, CSI.

[0128] CSI acquisition, specifically the acquisition or estimation by a gNB of a downlink channel response, is effected via CSI feedback from a UE. The CSI feedback from the UE may be used to assist the gNB to transmit multiple spatial layers (e.g. MIMO layers) to the UE on a downlink channel such as a Physical Downlink Shared Channel, PDSCH.

[0129] In such “downlink-derived” CSI acquisition, typically the UE would receive CSI-Reference Signal(s), RS, from the gNB on the downlink, DL, and the UE would estimate the downlink channel response, namely by performing measurements on the received CSI-RS. Based on the estimated DL channel, the UE would compute a feedback payload (i.e. a CSI payload) that typically comprises one or more of the following: a CSI-RS Resource Indicator, CRI, to indicate a preferred CSI-RS resource; a Rank Indicator, RI, conditioned on / determined based on the CRI; a Precoder Matrix Indicator, PMI to assist the gNB in computing the transmit precoding weights; and a Channel Quality Indicator, CQI, conditioned on / determined based on the combination of CRI, RI, and the PMI.

[0130] In 5G NR, one methodology of Downlink CSI acquisition is Type I CSI feedback. In Type I CSI feedback, the UE takes an estimated downlink channel (estimated based on the received CSI-RS) and computes a best Type I precoder for that estimated downlink channel.

[0131] The structure of a Type I precoder comprises a W1 matrix and a W2 matrix, and a final precoder matrix is a multiplication of W1 and W2. The W1 matrix has columns selected based on a set of Discreet Fourier Transform, DFT, vectors and are wideband in nature (i.e. applicable across a whole signal bandwidth). The W2 matrix is per-sub-band and enables some level of tracking of variations in a spatial channel response across the signal bandwidth.

[0132] In 5G NR, a codeword is a set of Quadrature Amplitude Modulation, QAM, symbols carrying coded bits, where all the bits in the codeword are encoded and decoded as a single “package”. A single MCS is assumed for a codeword. Each codeword can have its own MCS. Each codeword gets mapped to a set of layers that will transport that codeword according to a “codeword-to-layer mapping” strategy as defined in the standard for 5GNR.

[0133] In 5G NR, a codeword-to-layer mapping strategy is as follows.

[0134] For four or fewer layers, a single codeword (with a single Modulation and Coding Scheme, MCS, level and an associated Hybrid Automatic Repeat Request, HARQ, process) is mapped to the multiple layers.

[0135] For more than 4 layers and up to 8 layers, two codewords are mapped to the multiple layers, where both codewords have their own MCS level and associated HARQ process.

[0136] When multiple layers are precoded towards a UE, it is inevitable that the different layers will have different overall “quality” when received at the output of the multi-layer receiver at the UE (e.g. Minimum Mean Square Error, MMSE; and Interference Rejection Combining, IRC, etc.). The UE must estimate a best rank (number of layers) and provide an estimate of a CQI for each codeword, where those estimates should be computed to be the best values given the estimated Signal-to- Interference-plus-Noise Ratio, SINR, profile at the output of the UE’s multi-layer receiver.

[0137] In real -world networks, a typical UEs support a maximum of 4 layers in downlink, which implies the use of a single codeword being mapped across the multiple layers.

[0138] For four or fewer layers, the use of a single codeword means a single codeword must span multiple layers having potentially significant differences in overall quality. The rank (number of layers) and the associated MCS must be chosen to best fit the estimated SINK profile across OFDM resource elements across the signal bandwidth for each received layer. This selection of the RI and the CQI report for the single codeword is a UE implementation, and therefore the gNB has no control over how the UE computes the RI and the CQI.

[0139] Current field results, in real world networks, indicate that the UEs tend to report CQI (and by extension the MCS) that follows the weakest layer. Accordingly, in real world networks, it was found that the CQI fed back by the UE led to a selection of the MCS that tended to follow the weakest layer (especially for high code rate MCS), which is not necessarily the optimal approach.

[0140] It would be beneficial to adjust the transmission, TX, power being fed to each layer (e.g. not least for Sounding Reference Signal, SRS, based DL beamforming where the precoding is proprietary).

[0141] However, current 5G NR CSI payload (for, e.g. Type I CSI, which includes at least one or more of the following: CRI, RI, PMI, LI, CQI) provides no information that would assist the TX power adjustment across the multiple layers. For example, in the Type I CSI, there is nothing in the W1 or W2 that provides any information on the relative strength or quality of the multiple spatial layers that would be formed when the multiple layers are formed based on the W 1 and W2 components of the Type I CSI.

[0142] As will be set out in further detail below, in certain examples of the present disclosure a UE determines a quality of different layers that would be formed based on the UE’s feedback for a Type I precoder (not least CSI comprising RI, PMI, and CQI). In this regard, the UE leverages measurement of a CSLRS to estimate the downlink channel over which a Type I precoder would be applied. The UE can thencalculate an estimate of a SINR of each layer based on an aggregation of the Type I precoder with the estimated DL channel. The UE then provides an indication to the gNB on a relative strength of the layers that would be formed by the fed back Type I PMI so as to assist the gNB in adjusting power fed to different layers in order to maximize a throughput given the RI, PMI, and CQI fed back by the UE.

[0143] In this regard, the gNB may be provided with feedback information for assisting the gNB in making per-layer / layer-level power adjustments, e.g. power adjustments at a granularity of an individual layer as compared to legacy power adjustments which are ‘per-set of layers’ power adjustments / set of layers-level power adjustments i.e. at a granularity of an entire set of layers (i.e. the set of layers being a set of layers mapped to a codeword).

[0144] Advantageously, certain examples of the disclosure may thereby enable a UE to provide a gNB with information to assist the gNB in adjusting power for one or more layers so as to implement a layer balancing scheme or more generally to implement whatever power adjustment scheme the gNB prefers, for example so as to enable the gNB to balance its MIMO layers in Downlink within a Type I CSI framework.

[0145] In this regard, certain examples of the disclosure propose new CSI feedback components (which may be referred to herein as “layer-balancing quantities” or “layer-balancing parameters”) that provide a gNB with information that can be used to adjust the power on layers that will be transmitted to a UE on a PDSCH. The “layer balancing quantities” can, in some examples, be incorporated into a CSI payload

[0146] As used herein, it is to be noted that the term “layer-balancing” is intended to have a broad meaning and to mean the generic practice of adjusting transmit powers of layers to meet some criteria (wherein the criteria and algorithm for effecting the same may be based on gNB implementation). For instance, one possible criteria isthat transmit powers of layers could be adjusted so that they all have equal SINK at an output of a receiver processing. A ‘water-filling’ type of transmit adjustment could be another criteria.

[0147] Examples of the present invention seek to provide a gNB with a set of information that can be used to enable a layer power adjustment strategy to be employed (e.g. a generic layer power adjustment or any particular desired layer power adjustment. The actual layer power adjustment strategy employed may be decided / chosen by the gNB.

[0148] Examples of the present disclosure cover three main situations / signalling use cases where layer balancing quantities are computed, by a UE, and fed back to a gNB (optionally along with a legacy CSI payload).

[0149] The three situations / use cases are shown and discussed in further detail below with respect to:FIGs.3 & 4FIGs.4 & 6; andFIGs. 7 & 8 respectively.

[0150] There now follows a brief description of the three situations / use cases in terms of the required signalling steps.

[0151] Signalling Use Cases for sending layer balancing quantities:

[0152] Use Case 1 - CSI-RS use-case:• gNB transmits CSI-RS• UE computes PMI, RI, CQI based on CSI-RS (i.e. legacy CSI components)• UE computes “layer balancing quantities” for enabling layer balancing. (The layer balancing quantities are new signalling and are described below). Thecomputation of the layer balancing quantities is based, at least in part, on the CSI payload, i.e. the PMI, RI, CQI computed by the UE.• UE sends CSI payload comprising the legacy CSI components and also the layer balancing quantities.• gNB transmits PDSCH with precoding and power adjustment / scaling of the power of the layers based on the CSI payload received from the UE (which includes the layer balancing quantities). The power of the layers may be adjusted by the gNB based on the layer balancing quantities in the CSI payload to “balance” the layers seen on the PDSCH.

[0153] Use Case 2 - Layer-balancing CSLRS use case:• gNB transmits CSLRS• UE computes and feeds back a CSI payload comprising legacy CSI quantities (e.g. RI, PMI, CQI) plus the layer balancing quantities• gNB transmits a UE-specific “layer-balancing CSLRS”. The layer-balancing CSLRS can be formed by: o precoding a CSLRS with the PMI fed back by the UE, or o precoding a CSLRS with the same precoder that is to be used for a PDSCH to be transmitted to the UE. This may be done should the gNB chose to deviate from a recommended precoder via the UE’s PMI feedbackThe number of ports in the layer-balancing CSLRS is equal to the RI fed back by the UE. Each port in the layer-balancing CSLRS corresponds to a layer that will be transmitted later to the UE on the PDSCH. When transmitting the layer-balancing CSLRS, the gNB adjusts the transmit power of the ports in the precoded CSLRS in order to “balance” the layers formed by “PDSCH matched” precoding of the CSLRS. (The algorithm and criteria used to adjust the powers of the layers [CSLRS ports in this case] may be down to gNB implementation). The gNB may apply different transmit power to the CSLRS ports as part of the precoding weights applied to each port. The gNB mayconfigure the ratio between the PDSCH Energy Per Resource Element, EPRE, and CSI-RS EPRE (also referred to as power control ratio or Pc ratio) applicable to the CSI-RS resource. Alternatively, the gNB may dynamically configure, by Radio Resource Control, RRC, or a dynamic indication, a different power control ratio per CSI-RS port or port groups. This per-CSI- RS-port power indication by the gNB could be in the form of a power restriction and / or power boosting levels configured, for example, in a CSI report without PMI with or without non-PMI-Portlndication.• UE computes and sends updated layer balancing quantities based on the received layer-balancing CSI-RS, wherein each port of the layer-balancing CSI-RS corresponds to a layer expected to be transmitted on the PDSCH.• gNB transmits PDSCH with the precoding and power scaling of the layer powers based on the CSI payload and the updated layer balancing quantities received from the UE. The power of the layers may be adjusted by the gNB based on the quantities in the CSI payload and the updated layer balancing quantities to “balance” (adjust) the layers seen on the PDSCH.

[0154] Use case 3 - PDSCH-DMRS use case:• gNB transmits CSI-RS• UE computes and feeds back a CSI payload comprising legacy CSI quantities (e.g. RI, PMI, CQI) and also “layer balancing quantities” (i.e. in a manner similar to that of the CSI-RS-based use case discussed above)• gNB transmits PDSCH with precoding and power scaling of the layer powers based on the CSI payload received from the UE. (i.e. in a manner similar to that of the CSI-RS-based use case discussed above)• UE sends updated CSI and updated layer balancing quantities based on the layers received on the PDSCH, leveraging Demodulation Reference Signal. DM-RS, on each layer of the PDSCH. The updated CSI comprises at least the updated CQI of the layers received on the PDSCH. The updated layer balancing parameters are based on the layers received on the PDSCH and arebased at least in part on the CQI of the PDSCH layers (as measured by the perlayer DMRS).• gNB transmits PDSCH with precoding and power scaling of the layer powers based on the CSI payload and updated layer balancing quantities received from the UE. The power of the layers can be adjusted by the gNB based on the quantities in the CSI payload (which includes the updated layer balancing quantities calculated based on both the CSI-RS and / or PDSCH) to “balance” the layers seen on the PDSCH.

[0155] There are several examples of specific layer balancing quantities that can be estimated and fed back to the gNB to provide the gNB with sufficient information to enable the gNB to implement a layer balancing scheme of the gNB’s choice (the algorithm employed by the gNB for adjusting TX power per layer is a gNB implementation).

[0156] There now follows a brief description of several examples of such layer balancing quantities.Layer Balancing Quantities:Embodiment 1 :

[0157] In a first embodiment of layer balancing quantities, the layer balancing quantities take the form of:• first information indicative of which individual one or more layers require a power adjustment. In this regard the first information provides a per-layer indication of which layers of a codeword require a power adjustment. The first information may be provided in the form of a bitmap, which may be referred to herein as a “Layer Boosting Bitmap”, LBB.• second information indicative of an amount of power adjustment required. In this regard, the second information provides information for assisting the gNB in adjust the power to each layer of a codeword. The second information may be provided in the form of a vector, which may be referred to herein as “Boosting Information Vector”, BIV.Layer Boosting Bitmap, LBB

[0158] The LBB is a bitmap across all layers in the codeword, wherein each bit corresponds to a layer (i.e. such that for N layers the bitmap would be N bits).

[0159] For the CSLRS use case, the layers in the LBB correspond to the layers that would be formed based on RI and PMI fed back to the gNB by the UE.

[0160] For the layer-balancing CSLRS use case, the layers in the LBB correspond to the number of ports in the layer-balancing CSLRS (each port in the CSLRS corresponds to a layer).

[0161] For the PDSCH-DMRS-based use case, the layers in the LBB correspond to the layers received on a PDSCH (as measured by the DMRS for each layer). DMRS are reference signals that the receiver / UE uses to estimate the total overall channel that the layer is transmitted over (where “total overall channel” includes the effects of TX beamforming / precoding and a multipath channel). The channel estimated from the DMRS on the different layers will indicate the level of power imbalance on the different layers.

[0162] In some examples of an LBB, a 1 indicates that the layer needs power boosting relative to a layer indicated by a 0.

[0163] In some examples, the LBB can be used to indicate which layers require a power reduction (i.e. a “de-boost”). For instance, a 1 may indicate that the layer needs power reduction relative to a layer indicated by a 0.Boosting Information Vector, BIV

[0164] The BIV is a vector over the layers, wherein the BIV length is based on the number of layers in the codeword. In this regard, the number of entries in the vector is based on (or equal to) the number of layers. In some examples (e.g. the below mentioned alternative 1.a), for N layers the vector would comprise N entries.

[0165] Four possible alternatives for BIV are discussed below.Alternative l.a:

[0166] In alternative l.a, the BIV represents / is encoded as a layer delta CQI / SINR vector. Each entry in the vector contains a difference in CQI (or equivalent SINR) for that layer relative to CQESINR fed back, i.e. fed back as part of legacy CSI quantities.Alternative l.b:In alternative l.b, the BIV represents / is encoded as the CQI or SINR relative to a particular one of the layers.

[0167] The particular layer may be, but is not limited to, the strongest layer (which can be indicated by a Layer Indicator, LI, CSI quantity), in which case the length of the vector is RI-1.

[0168] The entries of the BIV could be, for instance, 3 -bit values corresponding to 8 possible values with steps of 1, 2, or 3 dB steps in between the values. However, it is to be appreciated that other encoding methods are possible.Alternative l.c:

[0169] In alternative l.c, the BIV represent a difference in SINR (ASINR) between successive layers.

[0170] For example, if the step size were 3dB, then the ASINR values could range from 0 to 21 dB (0, 3, 6, 9, 12, 15, 18, 21 dB). Thus, for 3 layers the BIV could be [0001 0010] corresponding to 3 dB difference between layer 1 and layer 2, and 6dB difference between layer 2 and layer 3.Alternative 2

[0171] In alternative 2, the BIV represents a vector over the layers (i.e. a vector whose length = number of layers in the codeword), wherein each entry in the vector contains the UE’s recommendation for a relative power boosting that should be applied to the layers. Similar encoding methods as described in the previous bullet can be used. Such a vector may be referred to as a Layer delta TX power vector.

[0172] It is to be appreciated that the Layer Balancing Quantities are not limited to the above described LBBs and BIVs, and that other options, variations and encodings would be possible. Likewise, there would also be many possible options for encoding the quantities in the corresponding per-layer vector.

[0173] The bitmap (LBBs) and the additional per-layer vector (BIV) may be specific to the layers that are mapped to a given codeword. If two codewords are to betransmitted, then each codeword would have its own bitmap and per-layer boosting vector.Embodiment 2:

[0174] In a second embodiment of layer balancing quantities, the layer balancing quantities take the form of:• first information indicative of which individual one or more layers require a power adjustment. In this regard the first information provides a per-layer indication of which layers of a codeword require a power adjustment. The first information may be provided in the form of a bitmap, which may be referred to herein as a “Layer Quality Bitmap”, LQB.• second information indicative of an amount of power adjustment required. In this regard, the second information provides information for assisting the gNB in adjust the power to each layer of a codeword. The second information may be provided in the form of a vector, which may be referred to herein as “DeltaSINR vector”, DSV.Layer Quality Bitmap, LQB,

[0175] The LQB is a variation / al ternative to the LBB described above. Each bit in the LQB indicates whether the layer is a “good” layer (e.g. a 1 in the bitmap) or a “bad” layer (e.g. a 0 in the bitmap). A determination of whether a layer is “good” or “bad” may be based on SNR or SINR of the layer as seen by the UE’s receiver, for instance based on a layer’s SNR or SINR value relative to a threshold or reference value. For instance, a layer that has a SNR or SINR that is X dB less than that of the strongest layer could be considered “bad”.DeltaSINR vector, DSV

[0176] The DeltaSINR vector has two values: “DeltaSINRl” and “DeltaSINR2”.

[0177] “DeltaSINRl”, indicates a difference in an average SINK of all the “good” layers (i.e. those with bitmap value 1 in the LQB) relative to the CQI of all the layers in the codeword. DeltaSINRl would be applicable to each of the three use cases described above.

[0178] “DeltaSINR2” indicates a difference in the average SINR of all the “bad” layers (i.e. those with a bitmap value 0 in the LQB) relative to the CQI of all the layers. DeltaSINR2 would be applicable to each of the three use cases described above.

[0179] Various methods for encoding the DeltaSINRl and DeltaSINR2 can be used.

[0180] The layer balancing quantities of Embodiment 2 (i.e. the LQB and DSV) are intended to have a lower feedback overhead as compared to the layer balancing quantities of Embodiment 1 (i.e. the LBB and BIV).

[0181] The gNB can use the LQB and one or both of the two DeltaSINR values to determine how to balance the layers. The idea is that the “good” layers would be deboosted together while the “bad” layers would be boosted together. This represents a coarser adjustment than the layer balancing quantities of Embodiment 1, but has the advantage of lower overhead.

[0182] In effect, one may consider that Embodiment 1 provides layer balancing information at a level of an individual layer of a set of layers, i.e. layer balancing information per layer of a set of layers; whereas Embodiment 2 provides layer balancing information at level of a subset of a set of layers, i.e. layer balancing information per subset of a set of layers (in this instance wherein one subset is a group of “good” layers of the set of layers, and another subset is a group of “bad” layers of the set of layers]?

[0183] FIG. 3 schematically illustrates an example of a procedure 300 and a signaling framework, between: a first apparatus (one example of which is a UE 110), and a second apparatus (one example of which is a node of a RAN such as a BS 120) for supporting the above-discussed use case 1 referred to as “CSI-RS use-case”.

[0184] In the below description of FIG. 3, reference will be made to the procedure 300 involving a UE 110 and a BS 120. The procedure 300 is a procedure suitable for use in adjusting the BS’s DL Tx powers of MIMO layers of PDSCH.

[0185] In block 301, the UE 110 receives, from the BS 120, at least one Reference Signal, RS, 302. The RS may be a measurement RS such as a CSI-RS, for instance a legacy / classic non-precoded CSI-RS.

[0186] In block 303, the UE determines, based at least in part on the RS, a plurality of precoded layers of a channel. The UE may determine / estimate / predict precoded layers of a PDSCH expected to be transmitted by the BS to the UE, wherein the determination is based on measurements of the RS, e.g. CSI components determined by the UE from the RS (e.g. such as PMI, RI and CQI). The UE may use PMI and RI to determine / estimate precoding and a number of MIMO layers expected to be used by the BS in PDSCH. In this regard, the UE may determine / estimate a plurality of precoded layers that would be formed based on the RI and the PMI (i.e. RI and PMI determined by the UE, which may be reported to the BS [not shown in FIG. 3 - but is shown in step 2 of FIG. 4],

[0187] Furthermore, also in block 303, the UE determines, based at least in part on the RS, first information 305 indicative of at least one power adjustment 306 for at least one precoded layer of the plurality of precoded layers. Such first informationmay correspond to one or more of the previously discussed layer balancing quantities / parameters, not least such as LBV, BIS, LQB and DSV.

[0188] The UE may determine / evaluate / calculate the first information 305 based at least in part on one or more of the following: a number of the plurality of precoded layers, wherein the number of the plurality of precoded layers is determined based at least in part on one or more components of CSI (not least for example RI); or a precoding for the plurality of precoded layers, wherein the precoding is determined based at least in part on one or more components of CSI (not least for example PMI).

[0189] The first information may be for assisting the BS in determining / deciding transmission power adjustment s) for each layer of a PDSCH to be transmitted to the UE.

[0190] The first information may be indicative of at least one of the following: a power adjustment expected to be required for a precoded layer of the plurality of precoded layers expected to be transmitted by the BS; a power adjustment for each precoded layer of the plurality of precoded layers; or a first power adjustment of at least a first precoded layer of the plurality of precoded layers, wherein the first power adjustment is relative to a power of at least a second precoded layer of the plurality of precoded layers.

[0191] The first information may comprise an identification of which precoded layers of the plurality of precoded layers require power adjustment.

[0192] The first information may comprise a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of one or more precoded layers of the plurality of precoded layers, and wherein a value of each bit of the bitmap isrepresentative of whether a power adjustment is estimated to be required for the respective one or more precoded layers represented by the respective bit. In this regard, the first information may comprise information indicative of one or more layer balancing parameters, e.g. the LBB as discussed above.

[0193] The first information may provide an indication of a plurality of power adjustment amounts estimated to be required for the plurality of precoded layers. In this regard, the first information may comprise information indicative of one or more layer balancing parameters, e.g. the BIV as discussed above.

[0194] The first information may comprise an indication of a quality metric (e.g. CQI or SINR) for a layer of the plurality of precoded layers relative to at least one of: a first quality metric reported, by the apparatus, to the node of the RAN (e.g. CSI feedback, such as CQI / SINR, previously reported by the UE - this corresponds to the above-discussed Alternative l.a); a second quality metric for another of the plurality of precoded layers (this corresponds to the above-discussed Alternative l.b); or a third quality metric for a successive precoded layer of the plurality of precoded layers (this corresponds to the above-discussed Alternative l.c).

[0195] The first information may comprises an indication of an estimated power adjustment amount for one of the plurality of precoded layers relative to another of the plurality of precoded layers (this corresponds to the above-discussed Alternative 2).

[0196] The first information may comprises the first information further comprises an indication of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold power.

[0197] The first information may comprise a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative ofwhether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold (e.g. to determine whether the precoded layer is deemed to be a “good layer” or a bad layer” as discussed above with regards to the LQB layer balancing parameter.

[0198] The first information may comprise an indication of a quality metric (e.g. SINR) for the plurality of precoded layers that meet the threshold power (i.e. the subset of “good” layers) relative to a quality metric (e.g. SINR) for all of the plurality of precoded layers. In this regard, the first information may comprise information indicative of the DS VI layer balancing parameter discussed above.

[0199] The first information may comprise an indication of a quality metric (e.g. SINR) for the plurality of precoded layers that do not meet the threshold power (i.e. the subset of “bad” layers) relative to a quality metric (e.g. SINR) for all of the plurality of precoded layers. In this regard, the first information may comprise information indicative of the DSV2 layer balancing parameter discussed above.

[0200] In block 307, the UE transmits the first information 305 (which comprises an indication of at least one power adjustment 306 for at least one precoded layer of the plurality of precoded layers) to the BS.

[0201] The first information may be used by the BS to assisting the BS in determining / deciding transmission power adjustment(s) for each layer of a PDSCH to be transmitted to the UE [not shown in FIG. 3 - but is shown in step 3 of FIG. 4],

[0202] FIG. 4 schematically illustrates another example of a procedure 400 and a signaling framework for supporting the use case 1 - “CSI-RS use-case”, which involves CSI-RS transmission.

[0203] In step 1, a gNB 120 transmits, to a UE 110, a CSI-RS resource.

[0204] In some examples, the CSI-RS resource may be non-precoded. In other examples the CSI-RS resource could be beamformed / precoded and part of a CSI-RS resources set, in which case CRI could be computed by the UE and fed back to the gNB as part of a CSI payload to indicate the UE’s preferred CSI-RS resource.

[0205] The UE computes a set of CSI components. The CSI components may comprise: RI, PMI (e g. NR Type I), CQI, and CRI if necessary. The CSI components are computed by the UE based upon the channel seen upon reception by the UE of the CSI-RS resource.

[0206] In addition, the UE also computes layer balancing quantities - the different embodiments and alternatives of which (e.g. LBB, BIV, LQB and DSV) are discussed above. The UE includes the computed layer balancing quantities in a CSI payload.

[0207] In step 2, the UE transmits, to the gNB, the CSI payload that includes the layer balancing quantities (in this instance: LBB and BIV).

[0208] The gNB determines how to adjust a TX power on different layers (the number of different layers being indicated by the UE with its (legacy) RI quantity reported in step 2).

[0209] The gNB’s may adopt any suitable method / algorithm for adjusting the Tx powers of the layers, e.g. so as to implement a layer power adjustment strategy preferred by the gNB (which may be a generic layer power adjustment or any particular desired layer power adjustment). The actual layer power adjustment strategy employed may be decided / chosen by the gNB. Hence, the gNB’s method / algorithm for adjusting the Tx powers of the layers, based on the received layer balancing parameters, may be gNB implementation.

[0210] In step 3, the gNB transmits a precoded PDSCH comprising multiple layers whose TX power are adjusted by the gNB based at least in part on the received layer balancing parameters.

[0211] FIG. 5 schematically illustrates an example of a procedure 500 and a signaling framework, between: a first apparatus (one example of which is a UE 110), and a second apparatus (one example of which is a node of a RAN such as a BS 120) for supporting the above-discussed use case 2 referred to as “Layer-balancing CSL RS”.

[0212] In the below description of FIG. 5, reference will be made to the procedure 500 involving a UE 110 and a BS 120. The procedure 500 is a procedure suitable for use in adjusting the BS’s DL Tx powers of MIMO layers of PDSCH.

[0213] In block 501, the UE 110 receives, from the BS 120, at least one precoded RS 502. The precoded RS may be a precoded measurement RS such as a precoded CSL RS.

[0214] In block 503, the UE determines, based at least in part on the precoded RS, a plurality of precoded layers of a channel (e.g. precoding of layers of a PDSCH expected to be transmitted by the BS to the UE.

[0215] In this regard, the precoded RS 502 transmitted by the BS in block 501 may be precoded (e.g. a precoded CSLRS) by the BS so as to have the same precoding as a precoding of a plurality of precoded layers of a channel (e.g. precoded layers of PDSCH) that is to be transmitted by the BS to the UE. Such a precoded RS 502 may be referred to as a “layer balancing CSI-RS”.

[0216] The BS may itself determine a precoding to use for the precoded RS 502 based at least in part on CSI components (e.g. such as PMI, RI and CQI) that the UE, prior to block 501, had previously determined (i.e. based on an earlier / previously received reference signal that had been previously transmitted by the BS) and previously reported to the BS, i.e. so that such determining and reporting of the CSI components occurs prior to block 501. Optionally, in addition to such determining and reporting of such legacy CSI components, the UE may also (prior to block 501) determine and report initial layer balancing information such as the information 305 of FIG. 3. Such steps are not shown in FIG. 5 but are shown in steps 1 and 2 of FIG. 6 as will be discussed below]. The BS may use the PMI and RI to determine a precoding and a number of MIMO layers it expects to use in the PDSCH for the UE, and the BS may apply the same precoding for the precoded RS of block 501 as the precoding for the layers of the PDSCH. Optionally, where initial layer balancing information is provided to the BS, the BS may use the initial layer balancing information to apply a preliminary adjustment of the Tx power of the precoded RS send in block 501.

[0217] The UE may determine the plurality of precoded layers of the channel based at least in part on the precoding of the at least one precoded reference signal.

[0218] The precoded reference signal may be transmitted by the BS over a plurality of antenna ports, wherein each of the antenna ports is mapped to a precoded layer of the plurality of precoded layers of the channel. Accordingly, the UE’s determining of the plurality of precoded layers of the channel may be based at least in part on the mapping of the plurality of antenna ports to the plurality of precoded layers of the channel.

[0219] Furthermore, also in block 503, the UE determines, based at least in part on the precoded RS, first information 505 indicative of at least one power adjustment 506for at least one precoded layer of the plurality of precoded layers. Such first information may correspond to one or more of the previously discussed layer balancing quantities / parameters, not least such as LBV, BIS, LQB and DSV.

[0220] The first information may be for assisting the BS in determining / deciding transmission power adjustment s) for each layer of a PDSCH to be transmitted to the UE.

[0221] The first information may be indicative of at least one of the following: a power adjustment expected to be required for a precoded layer of the plurality of precoded layers expected to be transmitted by the BS; a power adjustment for each precoded layer of the plurality of precoded layers; or a first power adjustment of at least a first precoded layer of the plurality of precoded layers, wherein the first power adjustment is relative to a power of at least a second precoded layer of the plurality of precoded layers.

[0222] The first information may comprise an identification of which precoded layers of the plurality of precoded layers require power adjustment.

[0223] The first information may comprise a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of one or more precoded layers of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a power adjustment is estimated to be required for the respective one or more precoded layers represented by the respective bit. In this regard, the first information may comprise information indicative of one or more layer balancing parameters, e.g. the LBB as discussed above.

[0224] The first information may provide an indication of a plurality of power adjustment amounts estimated to be required for the plurality of precoded layers. In this regard, the first information may comprise information indicative of one or more layer balancing parameters, e.g. the BIV as discussed above.

[0225] The first information may comprise an indication of a quality metric (e.g. CQI or SINK) for a layer of the plurality of precoded layers relative to at least one of• a first quality metric reported, by the apparatus, to the node of the RAN (e.g. CSI feedback, such as CQI / SINR, previously reported by the UE - this corresponds to the above-discussed Alternative l.a);• a second quality metric for another of the plurality of precoded layers (this corresponds to the above-discussed Alternative l.b); or• a third quality metric for a successive precoded layer of the plurality of precoded layers (this corresponds to the above-discussed Alternative l.c).

[0226] The first information may comprises an indication of an estimated power adjustment amount for one of the plurality of precoded layers relative to another of the plurality of precoded layers (this corresponds to the above-discussed Alternative 2).

[0227] The first information may comprises the first information further comprises an indication of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold power.

[0228] The first information may comprise a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold (e.g. to determine whether the precoded layer is deemed to be a “good layer” or a bad layer” as discussed above with regards to the LQB layer balancing parameter.

[0229] The first information may comprise an indication of a quality metric (e.g.SINR) for the plurality of precoded layers that meet the threshold power (i.e. the subset of “good” layers) relative to a quality metric (e.g. SINR) for all of the pluralityof precoded layers. In this regard, the first information may comprise information indicative of the DS VI layer balancing parameter discussed above.

[0230] The first information may comprise an indication of a quality metric (e.g. SINR) for the plurality of precoded layers that do not meet the threshold power (i.e. the subset of “bad” layers) relative to a quality metric (e.g. SINR) for all of the plurality of precoded layers. In this regard, the first information may comprise information indicative of the DSV2 layer balancing parameter discussed above.

[0231] In block 507, the UE transmits the first information 505 (which comprises an indication of at least one power adjustment 506 for at least one precoded layer of the plurality of precoded layers) to the BS.

[0232] The first information may be used by the BS to assisting the BS in determining / deciding transmission power adjustment(s) for each layer of a PDSCH to be transmitted to the UE [not shown in FIG. 5 - but is shown in step 5 of FIG. 6],

[0233] FIG. 6 schematically illustrates another example of a procedure 600 and a signaling framework for supporting the use case 2 - “Layer-balancing CSLRS”, which involves the transmission of a layer-balanced CSLRS. The use of layer-balancing CSLRS represents an alternative approach for providing a gNB with information that would enable the gNB to adjust the transmit powers of PDSCH layers transmitted to a UE.

[0234] In step 1, a gNB 120 transmits, to a UE 110, CSLRS for enabling the UE to compute CSI feedback, i.e. CSI components such as: PMI, RI, CQI.

[0235] In some examples, the CSLRS is not beamformed / precoded. In other examples the CSLRS is beamformed / precoded (and it may be part of a CSLRS resources set, in which case CRI could be computed by the UE and fed back to the gNB as part of a CSI payload to indicate the UE’s preferred CSLRS resource).

[0236] The UE computes a set of CSI components. The CSI components may comprise: RI, PMI (e g. NR Type I), CQI, and CRI if necessary. The CSI components are computed by the UE based upon the channel seen upon reception by the UE of the CSI-RS resource.

[0237] Optionally, in addition, the UE may also compute layer balancing quantities - the different embodiments and alternatives of which (e.g. LBB, BIV, LQB and DSV) are discussed above. The UE may include the computed layer balancing quantities in a CSI payload. Such layer balancing quantities may be referred to as (initial) layer balancing quantities since, as discussed further with respect to step 4, any such initial layer balancing quantities may be subsequently updated.

[0238] In step 2, the UE transmits, to the gNB, the CSI payload that includes the CSI components (PMI, RI and CQI) and which also may further include layer balancing quantities (in this instance: LBB and BIV).

[0239] The gNB determines a UE-specific precoded CSI-RS for transmission to the UE, where the CSI-RS is precoded based on the PMI, RI provided by the UE in step 2. This UE-specific precoded CSI-RS is referred to as a ’’Layer-balancing CSI-RS”.

[0240] Optionally, where layer balancing quantities are also provided in step 2, the BS may determine an adjustment to TX powers on a number of antenna ports to be used to transmit the layer-balancing CSI-RS (wherein the number of antenna ports are mapped to a number of layers of PDSCH to be transmitted to the UE - i.e. in step 5).

[0241] In step 3, the gNB transmits the layer-balancing CSI-RS to the UE.

[0242] The precoding in step 3 is done according to gNB implementation, where the intention is to enable the UE to determine and feedback the (updated) layer balancing parameters (and possible updated CQI, etc.) in step 4.

[0243] In step 4, the UE computes (updated) layer balancing quantities (e.g. LBB, BIV, LQB and DSV) based on the received layer balancing CSI-RS and sends a CSI report to the gNB containing the (updated) layer balancing parameters. In this regard, if the UE previously computed and sent initial layer balancing quantities in step 2, the UE would compute and send updated layer balancing quantities in step 4. However, as previously noted, the computation and sending of initial layer balancing quantities in step 2 is optional.

[0244] In step 5, the gNB transmits a precoded PDSCH comprising multiple layers whose TX power are adjusted by the gNB based at least in part on the received (updated) layer balancing parameters.

[0245] The precoding is based on the RI, PMI and (updated) layer balancing parameters. The exact precoding and layer balancing methodology is a gNB implementation. In this regard, the gNB’s may adopt any suitable method / algorithm for adjusting the Tx powers of the layers, e.g. so as to implement a layer power adjustment strategy preferred by the gNB (which may be a generic layer power adjustment or any particular desired layer power adjustment).

[0246] As indicated above, an alternative to the procedure shown in FIG. 5, is for layer balancing parameters to be excluded from the feedback in step 2. In which case, the gNB, in step 3, sends UE-specific precoded CSI-RS (precoded based on the RI and PMI fed back in step 2), but any optimization of the Tx power adjustment on the layers / ports formed by the precoding may be difficult to do (but it would still be up to the gNB - the gNB may simply transmit equal powers on the layers / ports of the precoded CSI-RS). The advantage for the UE in including initial layer balancing parameters in the feedback in step 2 is that it enables the gNB to optimise the Tx power adjustment on the layers / ports formed by the precoding of the layer balancing CSI-RS transmitted in step 3. This means that UE would directly see the layers through the precoded channel in step 3 and therefore will not have to compute thecombination of the PMI with the un-precoded CSI-RS as would have to be done in step 2 of FIG. 4, which thereby saves the UE some computations.

[0247] With the procedure 500 of FIG. 5, (updated) layer balancing parameters may be provided by the UE to the gNB so that PDSCH layers can be balanced in the very first PDSCH transmission (step 5 of FIG. 5).

[0248] By contrast, in the below described procedures 700 and 800 of FIGs. 7 and 8, the layer balancing parameters are determined and fed back after the first PDSCH transmission has happened (see for example step 3 of FIG. 8). Therefore, in these procedures, the layer balancing parameters are available only for use on the second PDSCH transmission (see for example step 5 of FIG. 8) and also any subsequent PDSCH transmissions.

[0249] FIG. 7 schematically illustrates an example of a procedure 700 and a signaling framework, between: a first apparatus (one example of which is a UE 110), and a second apparatus (one example of which is a node of a RAN such as a BS 120) for supporting the above-discussed use case 3 referred to as “PDSCH-DMRS use case”.

[0250] In the below description of FIG. 7, reference will be made to the procedure 700 involving a UE 110 and a BS 120. The procedure 700 is a procedure suitable for use in adjusting the BS’s DL Tx powers of MIMO layers of PDSCH.

[0251] In block 701, the UE 110 receives, over a plurality of precoded layers 704 of a channel (e.g. PDSCH having precoded layers) from the BS 120, at least one RS 702 (e g. DMRS).

[0252] The BS may itself determine a precoding to use for the precoded layers 704 of the channel based at least in part on CSI components (e.g. such as PMI, RI and CQI) that the UE, prior to block 701, had previously determined (i.e. based on an earlier / previously received reference signal that had been previously transmitted by the BS) and previously reported to the BS, i.e. so that such determining and reporting of the CSI components occurs prior to block 701. Such steps are not shown in FIG. 7 but are shown in steps 1 and 2 of FIG. 8 as will be discussed below]. The BS may use the PMI and RI to determine a precoding and a number of MIMO layers for the PDSCH.

[0253] In block 703, the UE determines, based at least in part on the RS, first information 705 indicative of at least one power adjustment 706 for at least one precoded layer of the plurality of precoded layers 704. Such first information may correspond to one or more of the previously discussed layer balancing quantities / parameters, not least such as LBV, BIS, LQB and DSV.

[0254] The first information may be for assisting the BS in determining / deciding transmission power adjustment s) for each layer of a (subsequent) PDSCH transmission to be transmitted to the UE.

[0255] The first information may be indicative of at least one of the following: a power adjustment expected to be required for a precoded layer of the plurality of precoded layers expected to be transmitted by the BS; a power adjustment for each precoded layer of the plurality of precoded layers; or a first power adjustment of at least a first precoded layer of the plurality of precoded layers, wherein the first power adjustment is relative to a power of at least a second precoded layer of the plurality of precoded layers.

[0256] The first information may comprise an identification of which precoded layers of the plurality of precoded layers require power adjustment.

[0257] The first information may comprise a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of one or more precoded layers of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a power adjustment is estimated to be required for the respective one or more precoded layers represented by the respective bit. In this regard, the first information may comprise information indicative of one or more layer balancing parameters, e.g. the LBB as discussed above.

[0258] The first information may provide an indication of a plurality of power adjustment amounts estimated to be required for the plurality of precoded layers. In this regard, the first information may comprise information indicative of one or more layer balancing parameters, e.g. the BIV as discussed above.

[0259] The first information may comprise an indication of a quality metric (e.g. CQI or SINR) for a layer of the plurality of precoded layers relative to at least one of• a first quality metric reported, by the apparatus, to the node of the RAN (e.g. CSI feedback, such as CQI / SINR, previously reported by the UE - this corresponds to the above-discussed Alternative l.a);• a second quality metric for another of the plurality of precoded layers (this corresponds to the above-discussed Alternative l.b); or• a third quality metric for a successive precoded layer of the plurality of precoded layers (this corresponds to the above-discussed Alternative l.c).

[0260] The first information may comprises an indication of an estimated power adjustment amount for one of the plurality of precoded layers relative to another of the plurality of precoded layers (this corresponds to the above-discussed Alternative 2).

[0261] The first information may comprises the first information further comprises an indication of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold power.

[0262] The first information may comprise a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold (e.g. to determine whether the precoded layer is deemed to be a “good layer” or a bad layer” as discussed above with regards to the LQB layer balancing parameter.

[0263] The first information may comprise an indication of a quality metric (e.g. SINR) for the plurality of precoded layers that meet the threshold power (i.e. the subset of “good” layers) relative to a quality metric (e.g. SINR) for all of the plurality of precoded layers. In this regard, the first information may comprise information indicative of the DS VI layer balancing parameter discussed above.

[0264] The first information may comprise an indication of a quality metric (e.g. SINR) for the plurality of precoded layers that do not meet the threshold power (i.e. the subset of “bad” layers) relative to a quality metric (e.g. SINR) for all of the plurality of precoded layers. In this regard, the first information may comprise information indicative of the DSV2 layer balancing parameter discussed above.

[0265] In block 707, the UE transmits the first information 705 (which comprises an indication of at least one power adjustment 706 for at least one precoded layer of the plurality of precoded layers 704) to the BS.

[0266] The first information may be used by the BS to assisting the BS in determining / deciding transmission power adjustment s) for each layer of a subsequentPDSCH transmission to be transmitted to the UE [not shown in FIG. 7 - but is shown in step 5 of FIG. 8],

[0267] FIG. 8 schematically illustrates another example of a procedure 800 and a signaling framework for supporting the use case 3 - “PDSCH-DMRS use case”, wherein layer balancing quantities computed by a UE and sent to a gNB based on layers received during PDSCH reception. In this regard, the layer balancing parameters can be used as part of an overall CSI acquisition and PDSCH transmission framework. The use of PDSCH-DMRS represents yet another alternative approach for providing a gNB with information that would enable the gNB to adjust the transmit powers of PDSCH layers transmitted to a UE.

[0268] In step 1, a gNB 120 transmits, to a UE 110, CSI-RS for enabling the UE to compute CSI feedback, i.e. CSI components such as: PMI, RI, CQI.

[0269] In some examples, the CSI-RS is not beamformed / precoded. In other examples the CSI-RS is beamformed / precoded (and it may be part of a CSI-RS resources set, in which case CRI could be computed by the UE and fed back to the gNB as part of a CSI payload to indicate the UE’s preferred CSI-RS resource).

[0270] The UE computes a set of CSI components. The CSI components may comprise: RI, PMI (e g. NR Type I), CQI, and CRI if necessary. The CSI components are computed by the UE based upon the channel seen upon reception by the UE of the CSI-RS resource.

[0271] Optionally (though not shown in FIG. 8), in addition, the UE may also compute layer balancing quantities - the different embodiments and alternatives of which (e.g. LBB, BIV, LQB and DSV) are discussed above. The UE may include the computed layer balancing quantities in a CSI payload. Such layer balancing quantities may be referred to as (initial) layer balancing quantities which may be subsequently updated similar to that as may be done in Fig. 6.

[0272] In step 2, the UE transmits, to the gNB, the CSI payload that includes the CSI components (PMI, RI and CQI).

[0273] The gNB determines a precoding for a number of layers of a channel (e.g. a PDSCH with multiple precoded layers) based at least in part on the PMI and RI provided by the UE in step 2.

[0274] In step 3, the PDSCH is precoded based on the CSI feedback (PMI and RI) to form multiple layers for PDSCH transmission, and the UE receives the precoded PDSCH.

[0275] In step 4, the UE computes layer balancing quantities (e.g. LBB, BIV, LQB and DSV) based on the received precoded PDSCH and sends a CSI report to the gNB containing the layer balancing parameters.

[0276] In step 5, the next transmission of the PDSCH occurs, wherein the precoding and power allocation / Tx power adjustment of the layers is determined based at least in part on the layer balancing quantities fed back in step 4. Other CSI quantities may also be fed-back to the gNB in step 4, and the precoding and power allocation / Tx power adjustment of the layers of the next PDSCH transmission may also be based at least in part on the other CSI quantities.

[0277] There now follows a discussion of other aspects which are applicable to each of the procedures of FIGs. 3 to 8:

[0278] Multiple RI hypotheses - when the UE feeds-back a CSI payload to the BS, the CSI payload may be for two or more RI hypotheses (RI>1), where for each RI hypothesis, the CSI payload would contain the RI, PMI, CQI, and the layer balancing parameters contingent on the respective RI hypothesis.

[0279] Separate layer balancing parameters for each codeword - the layer balancing parameters (whether for a single value of RI or for multiple hypotheses for RI) would be applicable for the layers that a codeword is being mapped to. For example, for the case of RI>4, in 5GNR, two codewords would be mapped to the layers, and there would be a set of layer balancing parameters for each codeword.

[0280] Leveraging Layer Indicator, LI - another aspect is to leverage the Layer Indicator feedback from the UE which indicates which of the layers is the strongest layer as estimated by the UE. The layer balancing parameters could provide an indication of the relative strength of RI-1 layers relative to the strongest layer - as indicated by the LI. It is noted that this would only be applicable for RI>1, since if RI=1, then there would be no need for an LI nor any layer balancing parameters.

[0281] The signaling diagrams of FIGs. 3 to 8 (and the associated functionality variously discussed above), can be considered to illustrate a plurality of methods, in the sense that each signaling diagram can be considered to illustrate one or more actions, processes or procedures performed by / at a plurality of actors / entities (e.g. UE 110 and gNB 120). The signaling diagrams can therefore be considered to illustrate a plurality of individual methods performed by each respective individual actor / entity of the plurality of the actors / entities.

[0282] The above described component blocks and step (e.g. of the signaling diagrams) are functional and the functions, along with the further functions / functionalities described above, can be performed by a single physical entity (such as an apparatus as is described with reference to FIG. 9 - embodied in / as a UE and gNB). The functions described can also be implemented by a computer program (such as is described with reference to FIG. 10 - for execution by a processor of a UE and gNB).

[0283] FIG. 9 schematically illustrates a block diagram of an apparatus 10 for performing the methods, processes, procedures and signaling described in the presentdisclosure and illustrated in FIGs. 3 to 8. In this regard the apparatus can perform the roles of an entity (such as: UE and gNB) in the illustrated and described methods.

[0284] The component blocks of FIG. 9 are functional and the functions described can be performed by a single physical entity, not least such as a UE or gNB.

[0285] The apparatus comprises a controller 11, which could be provided within a device / entity, not least such as a UE or gNB.

[0286] The controller 11 can be embodied by a computing device, not least such as those mentioned above. In some, but not necessarily all examples, the apparatus can be embodied as a chip, chip set, circuitry or module, i.e. for use in any of the foregoing. As used here ‘module’ refers to a unit or apparatus that excludes certain parts / components that would be added by an end manufacturer or a user.

[0287] Implementation of the controller 11 can be as controller circuitry. The controller 11 can be implemented in hardware alone, have certain aspects in software including firmware alone or can be a combination of hardware and software (including firmware).

[0288] The controller 11 can be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program 14 in a general -purpose or special -purpose processor 12 that can be stored on a computer readable storage medium 13, for example memory, or disk etc, to be executed by such a processor 12.

[0289] The processor 12 is configured to read from and write to the memory 13. The processor 12 can also comprise an output interface via which data and / or commands are output by the processor 12 and an input interface via which data and / or commands are input to the processor 12. The apparatus can be coupled to or comprise one or more other components 15 (not least for example: a radio transceiver, sensors,input / output user interface elements and / or other modules / devices / components for inputting and outputting data / commands).

[0290] The memory 13 stores instructions such as a computer program 14 comprising such instructions (e.g. computer program instruct! ons / code) that controls the operation of the apparatus 10 when loaded into the processor 12. The instructions of the computer program 14, provide the logic and routines that enables the apparatus to perform the methods, processes and procedures described in the present disclosure and illustrated in FIGs. 3 to 8. The processor 12 by reading the memory 13 is able to load and execute the computer program 14.

[0291] The instructions may be comprised in a computer program, a non-transitory computer readable medium, a computer program product, a machine readable medium. 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). In some but not necessarily all examples, the computer program instructions may be distributed over more than one computer program.

[0292] Although the memory 13 is illustrated as a single component / circuitry it can be implemented as one or more separate components / circuitry some or all of which can be integrated / removable and / or can provide permanent / semi -permanent / dynamic / cached storage.

[0293] Although the processor 12 is illustrated as a single component / circuitry it can be implemented as one or more separate components / circuitry some or all of which can be integrated / removable. The processor 12 can be a single core or multi-core processor.

[0294] The apparatus can include one or more components for effecting the methods, processes and procedures described in the present disclosure and illustrated in FIGs. 3 to 8. It is contemplated that the functions of these components can be combined inone or more components or performed by other components of equivalent functionality. The description of a function should additionally be considered to also disclose any means suitable for performing that function.

[0295] Where a structural feature has been described, it can be replaced by means for performing one or more of the functions of the structural feature whether that function or those functions are explicitly or implicitly described.

[0296] Although examples of the apparatus have been described above in terms of comprising various components, it should be understood that the components can be embodied as or otherwise controlled by a corresponding controller or circuitry such as one or more processing elements or processors of the apparatus. In this regard, each of the components described above can be one or more of any device, means or circuitry embodied in hardware, software or a combination of hardware and software that is configured to perform the corresponding functions of the respective components as described above.

[0297] The apparatus can, for example, be: a user equipment, base station or network node of a mobile cellular telecommunication system. The apparatus can be embodied by a computing device, not least such as those mentioned above. However, in some examples, the apparatus can be embodied as a chip, chip set, circuitry or module, i.e. for use in any of the foregoing.

[0298] In one example, the apparatus is embodied on a client device, a UE, a mobile cellular telephone, a hand held portable electronic device, a mobile communication device, a wearable computing device or a personal digital assistant, that can additionally provide one or more audio / text / video communication functions (for example tele-communication, video-communication, and / or text transmission (Short Message Service (SMS) / Multimedia Message Service (MMS) / emailing) functions), interactive / non-interactive viewing functions (for example web-browsing, navigation, TV / program viewing functions), music recording / playing functions (for exampleMoving Picture Experts Group-1 Audio Layer 3 (MP3) or other format and / or (frequency modulation / amplitude modulation) radio broadcast recording / playing), downloading / sending of data functions, image capture function (for example using a (for example in-built) digital camera), and gaming functions, or any combination thereof.

[0299] In some examples (such as wherein the apparatus is provided within a UE 110), the apparatus 10 comprises: at least one processor 12; and at least one memory 13 storing instructions that, when executed by the at least one processor 12, cause the apparatus at least to: receive at least one reference signal from a node of a Radio Access Network, RAN; determine, based at least in part on the at least one reference signal: a plurality of precoded layers of a channel, and first information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers; and transmit the first information to the node of the RAN.

[0300] In some examples (such as wherein the apparatus is provided within a UE 110), the apparatus 10 comprises: at least one processor 12; and at least one memory 13 storing instructions that, when executed by the at least one processor 12, cause the apparatus at least to: receive at least one precoded reference signal from a node of a Radio Access Network, RAN; determine, based at least in part on the at least one precoded reference signal: a plurality of precoded layers of a channel, and first information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers of the channel; andtransmit the first information to the node of the RAN.

[0301] In some examples (such as wherein the apparatus is provided within a UE 110), the apparatus 10 comprises: at least one processor 12; and at least one memory 13 storing instructions that, when executed by the at least one processor 12, cause the apparatus at least to: receiving, over a plurality of precoded layers of a channel, at least one reference signal from a node of a Radio Access Network, RAN; determining, based at least in part on the at least one reference signal, first information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers; and transmitting the first information to the node of the RAN.

[0302] The above described examples find application as enabling components of: telecommunication systems; tracking systems, automotive systems; electronic systems including consumer electronic products; distributed computing systems; media systems for generating or rendering media content including audio, visual and audio visual content and mixed, mediated, virtual and / or augmented reality; personal systems including personal health systems or personal fitness systems; navigation systems; user interfaces also known as human machine interfaces; networks including cellular, non-cellular, and optical networks; ad-hoc networks; the internet; the internet of things (IOT); Vehicle-to-everything (V2X), virtualized networks; and related software and services.

[0303] The apparatus can be provided in an electronic device, for example, a mobile terminal, according to an example of the present disclosure. It should be understood, however, that a mobile terminal is merely illustrative of an electronic device that would benefit from examples of implementations of the present disclosure and, therefore, should not be taken to limit the scope of the present disclosure to the same. While in certain implementation examples, the apparatus can be provided in a mobileterminal, other types of electronic devices, such as, but not limited to: mobile communication devices, hand portable electronic devices, wearable computing devices, portable digital assistants (PDAs), pagers, mobile computers, desktop computers, televisions, gaming devices, laptop computers, cameras, video recorders, GPS devices and other types of electronic systems, can readily employ examples of the present disclosure. Furthermore, devices can readily employ examples of the present disclosure regardless of their intent to provide mobility.

[0304] FIG. 10, illustrates a computer program 14 which may be conveyed via a delivery mechanism 20. The delivery mechanism 20 can be any suitable delivery mechanism, for example, a machine readable medium, a computer-readable medium, a non-transitory computer-readable storage medium, a computer program product, a memory device, a solid-state memory, a record medium such as a Compact Disc Read-Only Memory (CD-ROM) or a Digital Versatile Disc (DVD) or an article of manufacture that comprises or tangibly embodies the computer program 14. The delivery mechanism can be a signal configured to reliably transfer the computer program. An apparatus can receive, propagate or transmit the computer program as a computer data signal.

[0305] In certain examples of the present disclosure, there is provided a computer program comprising instructions, which when executed by an apparatus (e.g. UE 110), cause the apparatus to perform at least the following or for causing performing at least the following: receiving at least one reference signal from a node of a Radio Access Network, RAN; determining, based at least in part on the at least one reference signal: a plurality of precoded layers of a channel, and first information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers; and transmitting the first information to the node of the RAN.

[0306] In certain examples of the present disclosure, there is provided a computer program comprising instructions, which when executed by an apparatus (e.g. UE 110), cause the apparatus to perform at least the following or for causing performing at least the following: receiving at least one precoded reference signal from a node of a Radio Access Network, RAN; determining, based at least in part on the at least one precoded reference signal: a plurality of precoded layers of a channel, and first information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers of the channel; and transmitting the first information to the node of the RAN.

[0307] In certain examples of the present disclosure, there is provided a computer program comprising instructions, which when executed by an apparatus (e.g. UE 110), cause the apparatus to perform at least the following or for causing performing at least the following: receiving, over a plurality of precoded layers of a channel, at least one reference signal from a node of a Radio Access Network, RAN; determining, based at least in part on the at least one reference signal, first information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers; and transmitting the first information to the node of the RAN.

[0308] References to ‘computer program’, ‘computer-readable storage medium’, ‘computer program product’, ‘tangibly embodied computer program’ etc. or a ‘controller’, ‘computer’, ‘processor’ etc. should be understood to encompass not only computers having different architectures such as single / multi- processor architectures and sequential (Von Neumann) / parallel architectures but also specialized circuits such as field-programmable gate arrays (FPGA), application specific circuits (ASIC), signal processing devices and other devices. References to computer program,instructions, code etc. should be understood to encompass software for a programmable processor or firmware such as, for example, the programmable content of a hardware device whether instructions for a processor, or configuration settings for a fixed-function device, gate array or programmable logic device etc.

[0309] As used in this application, the term ‘circuitry’ can refer to one or more or all of the following:(a) hardware-only circuitry 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 (for example firmware) for operation, but the software may not be present when it is not needed for operation.

[0310] 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 and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to a particular claim element, a baseband integrated circuit for a mobile device or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

[0311] Although various examples of the present disclosure have been described in the preceding paragraphs, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as set out in the claims.

[0312] The blocks illustrated in FIGs. 3 to 8 can represent actions in a method, functionality performed by an apparatus, and / or sections of instruct! ons / code in a computer program. The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block may be varied. Furthermore, it may be possible for some blocks to be omitted.

[0313] It will be understood that each block and combinations of blocks illustrated in FIGs. 3 to 8 as well as the further functionality described above, can be implemented by various means, such as hardware, firmware, and / or software including one or more computer program instructions. For example, one or more of the functions described above can be performed by a duly configured apparatus (such as an apparatus [as shown in FIG. 9] comprising means for performing the above described functionality). One or more of the functions / functionality described above can be embodied by a duly configured computer program (such as a computer program [as shown in FIG. 10] comprising computer program instructions which embody the functions / functionality described above and which can be stored by a memory storage device and performed by a processor).

[0314] As will be appreciated, any such computer program instructions can be loaded onto a computer or other programmable apparatus (i.e. hardware) to produce a machine, such that the instructions when performed on the programmable apparatus create means for implementing the functions / functionality specified in the blocks. These computer program instructions can also be stored in a computer-readable medium that can direct a programmable apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the blocks. The computer program instructions can also be loaded onto a programmable apparatus to cause a series of operational actions to be performed on the programmable apparatus to produce a computer-implemented process such thatthe instructions which are performed on the programmable apparatus provide actions for implementing the functions / functionality specified in the blocks.

[0315] Various, but not necessarily all, examples of the present disclosure can take the form of a method, an apparatus, or a computer program. Accordingly, various, but not necessarily all, examples can be implemented in hardware, software or a combination of hardware and software.

[0316] Various, but not necessarily all, examples of the present disclosure are described using flowchart illustrations and schematic block diagrams. It will be understood that each block (of the flowchart illustrations and block diagrams), and combinations of blocks, can be implemented by computer program instructions of a computer program. These program instructions can be provided to one or more processor(s), processing circuitry or controller(s) such that the instructions which execute on the same create means for causing implementing the functions specified in the block or blocks, i.e. such that the method can be computer implemented. The computer program instructions can be executed by the processor(s) to cause a series of operational block / steps / actions to be performed by the processor(s) to produce a computer implemented process such that the instructions which execute on the processor(s) provide block / steps for implementing the functions specified in the block or blocks.

[0317] Accordingly, the blocks support: combinations of means for performing the specified functions; combinations of actions for performing the specified functions; and computer program instructions / algorithm for performing the specified functions. It will also be understood that each block, and combinations of blocks, can be implemented by special purpose hardware-based systems which perform the specified functions or actions, or combinations of special purpose hardware and computer program instructions.

[0318] Various, but not necessarily all, examples of the present disclosure provide both a method and corresponding apparatus comprising various modules, means or circuitry that provide the functionality for performing / applying the actions of the method. The modules, means or circuitry can be implemented as hardware, or can be implemented as software or firmware to be performed by a computer processor. In the case of firmware or software, examples of the present disclosure can be provided as a computer program product including a computer readable storage structure embodying computer program instructions (i.e. the software or firmware) thereon for performing by the computer processor.

[0319] Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0320] Features described in the preceding description can be used in combinations other than the combinations explicitly described.

[0321] Although functions have been described with reference to certain features, those functions can be performable by other features whether described or not.

[0322] Although features have been described with reference to certain examples, those features can also be present in other examples whether described or not. Accordingly, features described in relation to one example / aspect of the disclosure can include any or all of the features described in relation to another example / aspect of the disclosure, and vice versa, to the extent that they are not mutually inconsistent.

[0323] The term ‘comprise’ is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising Y indicates that X can comprise only one Y or can comprise more than one Y. If it is intended to use ‘comprise’ with an exclusive meaning then it will be made clear in the context by referring to “comprising only one ...” or by using “consisting”.

[0324] In this description, the wording ‘connect’ and ‘communication’ and their derivatives mean operationally connected / in communication. It should be appreciated that any number or combination of intervening components can exist (including no intervening components), i.e. so as to provide direct or indirect connection / coupling / communication. Any such intervening components can include hardware and / or software components.

[0325] As used herein, the term "determine / determining" (and grammatical variants thereof) can include, not least: evaluating, calculating, computing, processing, deriving, measuring, investigating, identifying, looking up (for example, looking up in a table, a database or another data structure), ascertaining and the like. Also, "determining" can include receiving (for example, receiving information), retrieving / accessing (for example, retrieving / accessing data in a memory), obtaining and the like. Also, " determine / determining" can include resolving, selecting, choosing, establishing, inferring and the like.

[0326] As used herein, a description of an action should also be considered to disclose enabling, and / or causing, and / or controlling that action. For example, a description of transmitting information should also be considered to disclose enabling, and / or causing, and / or controlling transmitting information. Similarly, for example, a description of an apparatus transmitting information should also be considered to disclose at least one means or controller of the apparatus enabling, and / or causing, and / or controlling the apparatus to transmit the information.”

[0327] The term “means” as used in the description and in the claims may refer to one or more individual elements configured to perform the corresponding recited functionality or functionalities, or it may refer to several elements that perform such functionality or functionalities. Furthermore, several functionalities recited in the claims may be performed by the same individual means or the same combination of means. For example performing such functionality or functionalities may be causedin an apparatus by a processor that executes instructions stored in a memory of the apparatus.

[0328] References to a parameter, or value of a parameter, should be understood to refer to “data indicative of’, “data defining” or “data representative of’ the relevant parameter / parameter value if not explicitly stated (unless the context demands otherwise). The data may be in any way indicative of the relevant parameter / parameter value, and may be directly or indirectly indicative thereof.

[0329] In this description, reference has been made to various examples. The description of features or functions in relation to an example indicates that those features or functions are present in that example. The use of the term ’example’ or ‘for example’, ‘can’ or ‘may’ in the text denotes, whether explicitly stated or not, that such features or functions are present in at least the described example, whether described as an example or not, and that they can be, but are not necessarily, present in some or all other examples. Thus ‘example’, ‘for example’, ‘can’ or ‘may’ refers to a particular instance in a class of examples. A property of the instance can be a property of only that instance or a property of the class or a property of a sub-class of the class that includes some but not all of the instances in the class.

[0330] In this description, references to “a / an / the” [feature, element, component, means . . . ] are used with an inclusive not an exclusive meaning and are to be interpreted as “at least one” [feature, element, component, means . . .] unless explicitly stated otherwise. That is any reference to X comprising a / the Y indicates that X can comprise only one Y or can comprise more than one Y unless the context clearly indicates the contrary. If it is intended to use ‘a’ or ‘the’ with an exclusive meaning then it will be made clear in the context. In some circumstances the use of ‘at least one’ or ‘one or more’ can be used to emphasise an inclusive meaning but the absence of these terms should not be taken to infer any exclusive meaning. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or moreelements 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.

[0331] The presence of a feature (or combination of features) in a claim is a reference to that feature (or combination of features) itself and also to features that achieve substantially the same technical effect (equivalent features). The equivalent features include, for example, features that are variants and achieve substantially the same result in substantially the same way. The equivalent features include, for example, features that perform substantially the same function, in substantially the same way to achieve substantially the same result.

[0332] In this description, reference has been made to various examples using adjectives or adjectival phrases to describe characteristics of the examples. Such a description of a characteristic in relation to an example indicates that the characteristic is present in some examples exactly as described and is present in other examples substantially as described.

[0333] In the above description, the apparatus described can alternatively or in addition comprise an apparatus which in some other examples comprises a distributed system of apparatus, for example, a client / server apparatus system. In examples where an apparatus provided forms (or a method is implemented as) a distributed system, each apparatus forming a component and / or part of the system provides (or implements) one or more features which collectively implement an example of the present disclosure. In some examples, an apparatus is re-configured by an entity other than its initial manufacturer to implement an example of the present disclosure by being provided with additional software, for example by a user downloading such software, which when executed causes the apparatus to implement an example of the present disclosure (such implementation being either entirely by the apparatus or as part of a system of apparatus as mentioned hereinabove).

[0334] The above description describes some examples of the present disclosure however those of ordinary skill in the art will be aware of possible alternative structures and method features which offer equivalent functionality to the specific examples of such structures and features described herein above and which for the sake of brevity and clarity have been omitted from the above description.Nonetheless, the above description should be read as implicitly including reference to such alternative structures and method features which provide equivalent functionality unless such alternative structures or method features are explicitly excluded in the above description of the examples of the present disclosure.

[0335] Whilst endeavouring in the foregoing specification to draw attention to those features of examples of the present disclosure believed to be of particular importance it should be understood that the applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and / or shown in the drawings whether or not particular emphasis has been placed thereon.

[0336] The examples of the present disclosure and the accompanying claims can be suitably combined in any manner apparent to one of ordinary skill in the art. Separate references to an “example”, “in some examples” and / or the like in the description do not necessarily refer to the same example and are also not mutually exclusive unless so stated and / or except as will be readily apparent to those skilled in the art from the description. For instance, a feature, structure, process, block, step, action, or the like described in one example may also be included in other examples, but is not necessarily included.

[0337] Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment s) of the present disclosure. Further, while the claims herein are provided as comprising specific dependencies, it is contemplated that any claims can depend from any other claims and that to the extent that any alternative embodiments can result from combining, integrating, and / or omitting features of the various claims and / or changing dependencies of claims, anysuch alternative embodiments and their equivalents are also within the scope of the disclosure.

Claims

CLAIMS1. An apparatus (10, 100) comprising: at least one processor (12); and at least one memory (14) including computer program code (14), the at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform at least the following: receiving (501) at least one precoded reference signal (502) from a node (120) of a Radio Access Network, RAN; determining (303), based at least in part on the at least one precoded reference signal: a plurality of precoded layers (504) of a channel, and first information (505) indicative of at least one power adjustment (506) for at least one precoded layer of the plurality of precoded layers of the channel; and transmitting (507) the first information to the node of the RAN.

2. The apparatus of any previous claim, wherein the at least one precoded reference signal has the same precoding as the precoding of the plurality of precoded layers of the channel, and wherein the determining, based at least in part on the at least one precoded reference signal, the plurality of precoded layers of the channel further comprises determining the plurality of precoded layers based at least in part on the precoding of the at least one precoded reference signal.

3. The apparatus of any previous claim, wherein the at least one precoded reference signal is transmitted by the node of the RAN over a plurality of antenna ports; wherein each of the plurality of antenna ports is mapped to a precoded layer of the plurality of precoded layers of the channel; and wherein the determining, based at least in part on the at least one precoded reference signal, the plurality of precoded layers of the channel further comprises determining theplurality of precoded layers based at least in part on the mapping of the plurality of antenna ports to the plurality of precoded layers of the channel.

4. The apparatus of any previous claim, wherein the at least one memory stores instructions that, when executed by the at least one processor, further cause the apparatus to perform: receiving, from the node of the RAN, at least one second reference signal for estimating a condition of a radio channel; determining, based at least in part on the at least one second reference signal, at least one of the following: one or more components of channel state information, CSI; or second information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers; transmitting, to the node of the RAN, at least one of the following: the one or more components of the CSI, or the second information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers; and wherein, the at least one precoded reference signal is precoded by the node of the RAN based at least in part on at least one of the following: the one or more components of the CSI transmitted to the node of the RAN; or the second information transmitted to the node of the RAN.

5. The apparatus of any previous claim, wherein the first information is further indicative of at least one of the following: at least one power adjustment expected to be required for at least one precoded layer of a plurality of precoded layers expected to be transmitted by the node of the RAN; a power adjustment for each precoded layer of the plurality of precoded layers; orat least a first power adjustment of at least a first precoded layer of the plurality precoded layers wherein the first power adjustment is relative to a power of at least a second precoded layer of the plurality of precoded layers.

6. The apparatus of any previous claim, wherein the first information further comprises an identification of which precoded layers of the plurality of precoded layers require power adjustment.

7. The apparatus of any previous claim, wherein the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a power adjustment is estimated to be required for the respective precoded layer represented by the respective bit.

8. The apparatus of any previous claim, wherein the first information further comprises an indication of a plurality of power adjustment amounts estimated to be required for the plurality of precoded layers.

9. The apparatus of any previous claim, wherein the first information further comprises an indication of a quality metric for one of the plurality of precoded layers relative to at least one of a first quality metric reported, by the apparatus, to the node of the RAN; a second quality metric for another of the plurality of precoded layers; or a third quality metric for a successive precoded layer of the plurality of precoded layers.

10. The apparatus of any previous claim, wherein the first information further comprises an indication of an estimated power adjustment amount for one of the plurality of precoded layers relative to another of the plurality of precoded layers.

11. The apparatus of any previous claim, wherein the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of multiple precoded layers of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a power adjustment is estimated to be required for the respective multiple precoded layers represented by the respective bit.

12. The apparatus of any previous claim, wherein the first information further comprises an identification of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold power.

13. The apparatus of any previous claim, wherein the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold.

14. The apparatus of any previous claim, wherein the first information further comprises an indication of a quality metric for the plurality of precoded layers that meet the threshold power relative to a quality metric for all of the plurality of precoded layers.

15. The apparatus of any previous claim, wherein the first information further comprises an indication of a quality metric for the plurality of precoded layers that do not meet the threshold power relative to a quality metric for all of the plurality of precoded layers.

16. The apparatus of any previous claim, wherein the plurality of precoded layers represented by the bitmap correspond to: a plurality of ports used, by the node of the RAN, in transmitting the at least one precoded reference signal.

17. A method comprising: receiving (501), at an apparatus (10, 110), at least one precoded reference signal (502) from a node (120) of a Radio Access Network, RAN; determining (303), at the apparatus, based at least in part on the at least one precoded reference signal: a plurality of precoded layers (504) of a channel, and first information (505) indicative of at least one power adjustment (506) for at least one precoded layer of the plurality of precoded layers of the channel; and transmitting (507), from the apparatus to the node of the RAN, the first information.

18. A non-transitory computer readable medium (20) comprising program instructions (14) that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving (501) at least one precoded reference signal (502) from a node (120) of a Radio Access Network, RAN; determining (303), based at least in part on the at least one precoded reference signal: a plurality of precoded layers (504) of a channel, and first information (505) indicative of at least one power adjustment (506) for at least one precoded layer of the plurality of precoded layers of the channel; and transmitting (507) the first information to the node of the RAN.

19. An apparatus (10, 110) comprising: means (11) for receiving at least one precoded reference signal (502) from a node (120) of a Radio Access Network, RAN; means (11) for determining, based at least in part on the at least one precoded reference signal: a plurality of precoded layers (504) of a channel, and first information (505) indicative of at least one power adjustment (506) for at least one precoded layer of the plurality of precoded layers of the channel; andmeans (11) for transmitting the first information to the node of the RAN.

20. The apparatus of claim 19, wherein the at least one precoded reference signal has the same precoding as the precoding of the plurality of precoded layers of the channel, and wherein the determining, based at least in part on the at least one precoded reference signal, the plurality of precoded layers of the channel further comprises determining the plurality of precoded layers based at least in part on the precoding of the at least one precoded reference signal.

21. The apparatus of any of previous claims 19 to 20, wherein the at least one precoded reference signal is transmitted by the node of the RAN over a plurality of antenna ports; wherein each of the plurality of antenna ports is mapped to a precoded layer of the plurality of precoded layers of the channel; and wherein the determining, based at least in part on the at least one precoded reference signal, the plurality of precoded layers of the channel further comprises determining the plurality of precoded layers based at least in part on the mapping of the plurality of antenna ports to the plurality of precoded layers of the channel.

22. The apparatus of any of previous claims 19 to 21, further comprising: means for receiving, from the node of the RAN, at least one second reference signal for estimating a condition of a radio channel; means for determining, based at least in part on the at least one second reference signal, at least one of the following: one or more components of channel state information, CSI; or second information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers; means for transmitting, to the node of the RAN, at least one of the following: the one or more components of the CSI, orthe second information indicative of at least one power adjustment for at least one precoded layer of the plurality of precoded layers; and wherein, the at least one precoded reference signal is precoded by the node of the RAN based at least in part on at least one of the following: the one or more components of the CSI transmitted to the node of the RAN; or the second information transmitted to the node of the RAN.

23. The apparatus of any of previous claims 19 to 22, wherein the first information is further indicative of at least one of the following: at least one power adjustment expected to be required for at least one precoded layer of a plurality of precoded layers expected to be transmitted by the node of the RAN; a power adjustment for each precoded layer of the plurality of precoded layers; or at least a first power adjustment of at least a first precoded layer of the plurality precoded layers wherein the first power adjustment is relative to a power of at least a second precoded layer of the plurality of precoded layers.

24. The apparatus of any of previous claims 19 to 23, wherein the first information further comprises an identification of which precoded layers of the plurality of precoded layers require power adjustment.

25. The apparatus of any of previous claims 19 to 24, wherein the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a power adjustment is estimated to be required for the respective precoded layer represented by the respective bit.

26. The apparatus of any of previous claims 19 to 25, wherein the first information further comprises an indication of a plurality of power adjustment amounts estimated to be required for the plurality of precoded layers.

27. The apparatus of any of previous claims 19 to 26, wherein the first information further comprises an indication of a quality metric for one of the plurality of precoded layers relative to at least one of: a first quality metric reported, by the apparatus, to the node of the RAN; a second quality metric for another of the plurality of precoded layers; or a third quality metric for a successive precoded layer of the plurality of precoded layers.

28. The apparatus of any of previous claims 19 to 27, wherein the first information further comprises an indication of an estimated power adjustment amount for one of the plurality of precoded layers relative to another of the plurality of precoded layers.

29. The apparatus of any of previous claims 19 to 28, wherein the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of multiple precoded layers of the plurality of precoded layers, and wherein a value of each bit of the bitmap is representative of whether a power adjustment is estimated to be required for the respective multiple precoded layers represented by the respective bit.

30. The apparatus of any of previous claims 19 to 29, wherein the first information further comprises an identification of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold power.

31. The apparatus of any of previous claims 19 to 30, wherein the first information further comprises a bitmap comprising a plurality of bits, wherein each bit of the bitmap is representative of a precoded layer of the plurality of precoded layers, and wherein avalue of each bit of the bitmap is representative of whether a precoded layer of the plurality of precoded layers is estimated to have a power that meets a threshold.

32. The apparatus of any of previous claims 19 to 31, wherein the first information further comprises an indication of a quality metric for the plurality of precoded layers that meet the threshold power relative to a quality metric for all of the plurality of precoded layers.

33. The apparatus of any of previous claims 19 to 32, wherein the first information further comprises an indication of a quality metric for the plurality of precoded layers that do not meet the threshold power relative to a quality metric for all of the plurality of precoded layers.

34. The apparatus of any of previous claims 19 to 33, wherein the plurality of precoded layers represented by the bitmap correspond to: a plurality of ports used, by the node of the RAN, in transmitting the at least one precoded reference signal.

35. A computer program comprising instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving (501) at least one precoded reference signal (502) from a node (120) of a Radio Access Network, RAN; determining (303), based at least in part on the at least one precoded reference signal: a plurality of precoded layers (504) of a channel, and first information (505) indicative of at least one power adjustment (506) for at least one precoded layer of the plurality of precoded layers of the channel; and transmitting (507) the first information to the node of the RAN.

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