Transmit power allocation

Abstract

Embodiments of the present disclosure relate to transmit power allocation In an aspect, a terminal device obtains, a channel state information, CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. The terminal device determines, at least one CSI quantity, based on the indication of at least one type of allocation of transmit power across the at least one group of resources for the PDSCH. The terminal device transmits, to a network device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

Description

TRANSMIT POWER ALLOCATION CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of FI application No. 20246027, filed August 16, 2024. Thecontent of which are hereby incorporated by reference in their entirety. FIELD

[0002] Various example embodiments relate to the field of communication and in particular, to methods,devices, apparatuses and a computer readable storage medium for a transmit power allocation. BACKGROUND

[0003] A communication network can be seen as a facility that enables communications between two ormore communication devices, or provides communication devices access to a data network. A mobile or wireless communication network is one example of a communication network.

[0004] Such communication networks operate in accordance with standards, such as those promulgatedby 3GPP (Third Generation Partnership Project) or ETSI (European Telecommunications Standards Institute). Examples of such standards include the so-called 5G (5th Generation) standard or other standards promulgated by 3GPP. SUMMARY

[0005] In general, example embodiments of the present disclosure provide a solution for a transmit powerallocation. With this solution, the transmit power allocation across the groups of resource of PDSCH is provided, thereby improving the performance of communication with the transmit power allocation.

[0006] In a first aspect, there is provided a terminal device. The terminal device comprises at least oneprocessor and at least one memory storing instructions. The instructions, when executed by the at least one processor, cause the terminal device at least to obtain, a channel state information, CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. The terminal device is further caused to determine, at least one CSI quantity, based on the indication of at least one type of allocation of transmit power across the at least one group of resources for the PDSCH. The terminal device is further caused to transmit, to a network device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

[0007] In a second aspect, there is provided a network device. The network device comprises at least oneprocessor and at least one memory storing instructions. The instructions, when executed by the at least one processor, cause the network device at least to transmit, to a terminal device, a channel state information, CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. The network device is further caused to receive, from the terminal device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

[0008] In a third aspect, there is provided a method implemented at a terminal device. The methodcomprises obtaining, a channel state information, CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. The method further comprises determining, at least one CSI quantity, based on the indication of at least one type of allocation of transmit power across the at least one group of resources for the PDSCH. The method further comprises transmitting, to a network device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

[0009] In a fourth aspect, there is provided a method implemented at a network device. The methodcomprises transmitting, to a terminal device, a channel state information, CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. The method further comprises transmitting, to a network device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

[0010] In a fifth aspect, there is provided an apparatus. The apparatus comprises means for means forobtaining, a channel state information, CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. The apparatus further comprises means for determining, at least one CSI quantity, based on the indication of at least one type of allocation of transmit power across the at least one group of resources for the PDSCH. The apparatus further comprises means for means for transmitting, to a network device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

[0011] In a sixth aspect, there is provided an apparatus. The apparatus comprises means for means fortransmitting, to a terminal device, a channel state information, CSI, configuration including an indication of atleast one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. The apparatus further comprises means for receiving, from the terminal device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

[0012] In a seventh aspect, there is provided a non-transitory computer readable medium comprisingprogram instructions for causing an apparatus to perform at least the method according to any one of the above third and fourth aspects.

[0013] In an eighth aspect, there is provided a computer program comprising instructions, which, whenexecuted by an apparatus, cause the apparatus to perform at least the method according to any one of the above third and fourth aspects.

[0014] In a ninth aspect, there is provided a terminal device. The terminal device comprises obtainingcircuitry configured to obtain, a channel state information, CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. The terminal device further comprises determining circuitry configured to determine, at least one CSI quantity, based on the indication of at least one type of allocation of transmit power across the at least one group of resources for the PDSCH. The terminal device further comprises transmitting circuitry configured to transmit, to a network device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

[0015] In a tenth aspect, there is provided a network device. The network device comprises transmittingcircuitry configured to transmit, to a terminal device, a channel state information, CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. The network device further comprises receiving circuitry configured to receive from the terminal device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

[0016] It is to be understood that the summary section is not intended to identify key or essential featuresof embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Some example embodiments will now be described with reference to the accompanying drawings,in which:

[0018] FIG. 1A illustrates an example communication network in which embodiments of the presentdisclosure may be implemented;

[0019] FIG. 1B illustrates a flowchart illustrating an example of unequal power allocation across layersaccording to some embodiments of the present disclosure;

[0020] FIG. 2 illustrates a flowchart illustrating an example of process for transmit power allocationaccording to some embodiments of the present disclosure;

[0021] FIG. 3 illustrates a flowchart illustrating another example of process for transmit power allocationaccording to some embodiments of the present disclosure;

[0022] FIG. 4 illustrates an example of water-filling power allocation across layers according to someembodiments of the present disclosure;

[0023] FIG.5 illustrates an example of power allocation for equal SINRs across layers according to someembodiments of the present disclosure;

[0024] FIG. 6 illustrates an example of maximum per-antenna transmit power with water-filling powerallocation according to some embodiments of the present disclosure;

[0025] FIG. 7 illustrates an example of maximum per-antenna transmit power with power allocation forequal SINRs across layers according to some embodiments of the present disclosure;

[0026] FIG.8 illustrates a flowchart of a method implemented at a terminal device according to some otherembodiments of the present disclosure;

[0027] FIG.9 illustrates a flowchart of a method implemented at a network device according to some otherembodiments of the present disclosure;

[0028] FIG. 10 illustrates a simplified block diagram of an apparatus that is suitable for implementingembodiments of the present disclosure; and

[0029] FIG.11 illustrates a block diagram of an example computer readable medium in accordance withsome embodiments of the present disclosure.

[0030] Throughout the drawings, the same or similar reference numerals represent the same or similarelement. DETAILED DESCRIPTION

[0031] Principles of the present disclosure will now be described with reference to some exampleembodiments. It is to be understood that these embodiments are described only for the purpose ofillustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

[0032] In the following description and claims, unless defined otherwise, all technical and scientific termsused herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0033] References in the present disclosure to “one embodiment,” “an embodiment,” “an exampleembodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0034] It shall be understood that although the terms “first” and “second” etc. may be used herein todescribe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0035] The terminology used herein is for describing particular embodiments only and is not intended tobe limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0036] As used in this application, the term “circuitry” may refer to one or more or all of the following:(a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0037] This definition of circuitry applies to all uses of this term in this application, including in any claims.As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0038] As used herein, the term “communication network” refers to a network following any suitablecommunication standards, such as Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the future fifth generation (5G) and the sixth generation (6G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0039] As used herein, the term “network device” and “access network device” refer to a node in acommunication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR NB (also referred to as a gNB), a transmission reception point (TRP), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

[0040] The term “terminal device” refers to any end device that may be capable of wireless communication.By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS),or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle- mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0041] In NR multiple input multiple output (MIMO) operations, when a UE is configured for CSI reportingbased on measurement of reference signals (RS), the gNB configures the PDSCH transmit power for each RS resource in the resource configuration linked to the Report configuration. The PDSCH transmit power configured for a CSI-RS resource with ^^ ports, is configured in terms of energy per resource element (EPRE) across all the PDSCH layers whose symbols are transmitted from the ports of that resource. A UE assumes that the PDSCH is transmitted with the configured EPRE for the purpose of channel quality indication (CQI) calculation. NR specifications stipulate that a CQI shall be calculated conditioned on the reported precoding matrix indicator (PMI), rank indication (RI) and CSI-RS resource indicator (CRI); and that a PMI shall be calculated conditioned on the reported RI and CRI. There is no provision in current NR specifications for the PMI calculation to be conditioned on the transmit power allocation across frequency subbands and layers.

[0042] In fact, in all NR codebooks, for a rank-^^ reported PMI, the precoding matrix is formed by ^^precoding vectors of length equal to the number of ports of the CSI-RS resource(s), ^^^^^^ = 2^^1^^2. Eachprecoding vector corresponds to a MIMO layer in a PDSCH transmission for the entire reporting band in wideband reporting, or for each configured frequency subband in subband reporting. These layer-specific precoding vectors are power-normalized separately for each subband (or wideband) and for each layer, such that the squared norm of each precoding vector is 1 / ^^. Therefore, a CQI, conditioned on the reported RI and PMI, is calculated under the assumption of equal transmit power allocation across frequency subbands and layers.

[0043] In Type-I codebooks, all elements in a PMI matrix have unit norm and differ only by phase, henceType-I PMI codebooks are characterized by equal power allocation for all layers and subbands. In Type-II codebooks, the elements of a PMI matrix vary in both amplitude and phase. However, the quantizedamplitude of the strongest combination coefficient, after DFT compression in frequency, is normalized to one for each reported layer, and no information of the relative strength of layers is reported in the CSI. Each PMI vector is also normalized in power to 1 / ^^ for each subband, hence equal power allocation is assumed for CQI calculation across frequency subbands and layers.

[0044] In current NR specifications, regarding the assumptions for CSI calculation, a UE determines thePDSCH EPRE transmitted across all PDSCH layers transmitted on the ports of a CSI-RS resource from the ratio of PDSCH EPRE to CSI-RS EPRE (powerControlOffset, also referred to as Pc ratio) configured for that CSI-RS resource.

[0045] More precisely, as specified in Clause 5.2.2.5.1 of TS 38.214, a UE should assume PDSCH signalson antenna ports in the set [1000, … ,1000 + ^^ − 1] for ^^ layers would result in signals equivalent tocorresponding symbols transmitted on antenna ports [3000, … ,3000 + ^^^^^^ − 1], as given bywhere ^^(^^) = [^^(0)(^^), …^^(^^)]is a vector of PDSCH symbols from the codeword to layer mapping,^^^^^^ is the number of CSI-RS ports and ^^ is a ^^^^^^ × ^^ precoding matrix. The corresponding PDSCHsignals transmitted on antenna ports [3000, … ,3000 + ^^^^^^ − 1] would have a ratio of EPRE to CSI-RSEPRE configured by the network for a CSI-RS resource and defined as:where is the PDSCH signal of layer ^^, ^^^^^^^^is the number of CDM groups and ^^^^^^^^−^^^^is the scaling factor applied to the mapping of the CSI-RS resource to REs, according to Clause 7.4.1.5.3 of TS 38.211.

[0046] Therefore, a UE derives the total transmit power of the PDSCH across the ^^ layers on onesubcarrier, given byfrom the configured Pc offset, ^^^^. The UE assumes equal transmit power allocation across frequencysubbands and layers. If it is assumed that, before transmit power adjustment, the ^^ columns of theprecoding matrix are unit norm, i.e., ^^^^^^ = ^^, after transmit power scaling, the precoding matrix is givenby

[0047] Accordingly, there is no assumption by a UE on how the transmit power is distributed across the^^ transmit ports. In general, the total transmit power, ^^^^^^, is not equally distributed across the transmit antenna ports. And there is also no requirement or assumption related to the PDSCH power allocation across the ^^ antenna ports, for CQI calculation. A UE is not expected to assume equal power allocation across the transmit antenna ports.

[0048] However, MIMO precoding strategies based on zero-forcing and equal power allocation acrosslayers and frequency subbands are well known to perform poorly compared to more optimized transmit power allocation, such as water-filling. This is because of power imbalance between layers, i.e., different layers can experience very different channel gains, hence allocating the same transmit power to all layers may result in significant throughput penalty. In current NR specifications, the reported CQI assumes equal power allocation across layers and frequency subbands and the CSI does not provide sufficient information for the gNB to address the layer imbalance issue.

[0049] In the legacy assumption of equal transmit power distribution across layers, where ^^^^^^ is the totalconfigured transmit power of the PDSCH signals, a UE may assume the following per-layer power scaling factors ^^ ^^^^^^^^= ^^, ^^ = 1, … ^^

[0050] This simple power distribution assumption is not dependent on channel conditions, hence it doesnot need to be reported, however it may cause large SINR imbalance between layers because the SINR of a layer is proportional to the corresponding eigenvalue. Layer SINR imbalance is problematic when there are large SINR variations between layers of a same codeword as the weakest layers tend to reduce its CQI.

[0051] In addition, transmit power is typically limited per transmit antenna port, hence a power back-offmay be needed if transmit power is not equally distributed across transmit antennas. Not considering this per-antenna power limit when calculating the CQI may lead to overestimating the CQI. To illustrate this issue,an example of a ^^^^^^ × ^^ precoding matrix ^^ for ^^^^^^ = 4 transmit antenna ports and ^^ = 2 layersis considered. The power per layer in ^^ is normalized to one and the precoding vectors are orthogonalbetween layers, such that ^^^^^^ = ^^, however, power is not equally distributed across the 4 antenna ports,for example, ^^^^^^^^(^^^^^^) = [0.8192 0.5416 0.0692 0.5699]. Assume the PDSCH transmitpower across all layers is configured to be ^^^^^^ = 12, in linear scale, and the maximum transmit power perantenna port is ^^^^^^ / ^^^^^^ = 3. Without considering this per-antenna power limit, a UE would apply a powerscaling: ^^^^ √^^ ^^^^1, ^^1 =^^= 6 . However, this exceeds the per-antenna limit because^^^^^^^^(^^^^1^^^^) = [4.9155 3.2497 0.4153 3.4195] , and in practice a power backoff of ^^ =^^ / ^^^^^^max(^^^^^^^^(^^^^^^)) needs to be applied. This means that the transmit PDSCH power across the ^^ layers isreduced from ^^^^^^to ^^^^^^^^. Note that the backoff factor ^^ is always smaller or equal to one becauseIncluding the backoffresults in a power scaling= 3.6619, which fulfils the per per-antennalimit because ^^^^^^^^(^^^^^^2^^) = [3.0000 1.9833 0.2535 2.0870] at the cost of reduced totaltransmit power: 7.3238 < ^^^^^^ .

[0052] According to some embodiments of the present disclosure, there is provided a solution to overcomethose inconsistencies issues mentioned above and enable the transmit power allocation across the groups of resource of PDSCH. Principles and embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0053] FIG.1A illustrates a schematic diagram of an example communication network 100 in which someembodiments of the present disclosure can be implemented. As shown in FIG.1A, the communication network 100 may include a terminal device 110, a network device 120.

[0054] It is to be understood that the number of network devices and terminal devices is only for thepurpose of illustration without suggesting any limitations. The system 100 may include any suitable number of network devices and terminal devices adapted for implementing embodiments of the present disclosure.

[0055] Communications in the communication system 100 may be implemented according to any propercommunication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G) and the sixth generation (6G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0056] FIG. 1B illustrates a flowchart illustrating an example of unequal power allocation across layersaccording to some embodiments of the present disclosure. Specifically, FIG.1B illustrates a set of precodingmatrices, ^^ , of size ^^^^^^ × ^^ (in the example, ^^^^^^ = 8 and ^^ = 4 ), one for each of the ^^3frequency subbands, and the transmit power constraints that can be applied to their components: per-layer,per-antenna port and per-subband power constraints. The precoding vector for layer ^^ = 1, … , ^^ is the ^^-th column vector component of the precoding matrix ^^ = [^^1, … ,^^^^] , with ^^^^ =[^^^^,0,^^^^,1, … ,^^^^,^^^^^^−1]^^ and it is assumed, as per current NR specifications, that each precoding vectoris power-normalised, i.e., its norm is ‖^^^^‖ = 1. It is assumed that the signal received by a UE equippedwith ^^^^^^receive antennas is ^^ = ^^^^ + ^^where ^^ is the signal vector transmitted in parallel by the ^^^^^^ transmit antenna ports, ^^ =is the ^^^^^^ × ^^^^^^ channel measured by the UE from CSI-RS on a subband and ^^ ∈^^^^(^^, ^^) is the noise plus interference, that, for simplicity of analysis, it is assumed that it is an i.i.d. properGaussian vector. By taking the eigenvalue decomposition (EVD) of the channel such that ^^^^^^ = ^^^^^^^^where the eigenvalues,are in decreasing order of magnitude, and thecorresponding eigenvectors are given by ^^ = [^^1, … ,^^^^, … ,^^^^^^^^], a rank-^^ precoding matrix for thesubband is given by the ^^ strongest eigenvectors ^^ = [^^1, … ,^^^^]

[0057] In general, let ^^ = [^^1, … ,^^^^] indicate the ^^ × ^^ precoder matrix for PDSCH assumed bythe UE to calculate CQI, where ^^^^denotes the precoding vector for layer ^^ on a generic subband (orwideband). Let ^^ = ‖^^^^‖2 indicate the PDSCH transmit power on layer ^^ andpower-normalised precoding vector for layer ^^, such that ^^ = ^^^^^^^^^^(√^^)where ^^ = [^^1, … ,^^^^]^^is a vector of transmit power allocation across layers for a generic subband, or wideband. Legacy NR specifications provide codebook descriptions for reporting the power-normalised precoding matrix ^^ as PMI, for a selected rank ^^.

[0058] For PDSCH reception, the UE applies a ^^ × ^^^^^^ receive filter ^^ which outputs the estimatedreceive signals for the ^^ layers. Let ^^ the cross-t^^2alk matrix, such that Φ^^,^^ = |^^ ^^^^^^|,where ^^^^ =^^are the effective channels for layers 1 to ^^, combining propagation channel and receive filter. Under the assumption of linear precoding, the SINR of layer ^^ is given byand the following rates per layer are achievable ^^^^ = log(1 + ^^^^^^^^^^).

[0059] To illustrate the benefit of optimizing transmit power allocation, it is considered an example with apower-normalised precoder given by the ^^ strongest eigenvectors, ^^ = ^^, defined above and the receiveMIMO filter given by a matched filter, ^^ = (^^^^)^^. The SINR of layer ^^ becomes^^^^^^^^^^ = ^^^^^^^^, ^^ = 1, … , ^^

[0060] FIG. 2 illustrates a flowchart illustrating an example of process for transmit power allocationaccording to some embodiments of the present disclosure. For the purpose of discussion, the process 200 will be described with reference to FIG.1A. The process 200 may involve the terminal device 110, the network device 120 as illustrated in FIG.1A. It would be appreciated that although the process 200 for link has been described in the communication system 100 of FIG.1A, this process may be likewise applied to other communication scenarios where different network devices are jointly deployed.

[0061] In some embodiments, the network device 120 may transmits to the terminal device 110, a CSI,configuration 210 including an indication of at least one type of allocation of transmit power across at least one group of resources for a PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. In some embodiments, the terminal device 110 obtains 220 a CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. The terminal device 110 determines 230, at least one CSI quantity, based on the indication of at least one type of allocation of transmit power across the at least one group of resources for the PDSCH. The terminal device 110 transmits to the network device 120, at least one first indication 240 indicating a transmit power allocation across the at least one group of resources for the PDSCH.

[0062] With the solution of the process, those inconsistencies issues mentioned above are solved and thetransmit power allocation across the groups of resource of PDSCH is provided, thereby improving the performance of communication with transmit power allocation.

[0063] In some embodiments, the configuration for indicating the equal or unequal transmit powerallocation can be explicit. For example, the terminal device 110 receives the configuration from network device 120.

[0064] In some embodiments, the configuration for indicating the equal or unequal transmit powerallocation can be implicit. For example, the configuration can be specified by spec, or the terminal device 110 makes an assumption / decision based on information provided by spec or network device 120. If no explicit configuration, but the terminal device 110 assumes it as equal or unequal distribution, this can be regarded as implicit configuration.

[0065] In some embodiments, the group of resources comprise at least one of a layer, a group of layers,a subband, a group of subband, a codeword, a TRP. That is, it is understood that similar power allocations configurations, calculations and indications can apply to any group of resources where a group of resources can be: layers, group of layers, subbands, group of subbands, codewords, TRPs in case of multi-TRP PDSCHtransmission, etc.

[0066] FIG. 3 illustrates a flowchart illustrating another example of process for transmit power allocationaccording to some embodiments of the present disclosure. In FIG.3, there is detailed signaling workflow to support above-mentioned solution. For the purpose of discussion, the process 300 will be described with reference to FIG.1A. The process 300 may involve the terminal device 110, the network 120 as illustrated in FIG.1A. It would be appreciated that although the process 300 has been described in the communication system 100 of FIG. 1A, this process may be likewise applied to other communication scenarios where different network devices are jointly deployed.

[0067] As shown in FIG.3, the terminal device 110 transmits the UE capability indication of unequal powerallocation 310 to the network device 120. This will indicate if UE supports the unequal power allocation. And the network device 120 transmits CSI configuration 320 including unequal power allocation assumption, e.g an indication of at least one type of allocation of transmit power across layers to the terminal device 110. In some embodiments, the configuration may also comprise the per-antenna transmit power assumption e.g. indications of at least one type of the per-antenna transmit power.

[0068] Then the terminal device 110 performs 330 the CSI calculation with unequal power allocation acrosslayers. In some embodiments, the terminal device 110 can be configured to calculate one or more of the CSI components, e.g., CQI, under the assumption of unequal distribution of the PDSCH transmit power across the reported layers and / or codewords and / or frequency subbands and / or TRPs, etc. Different criteria may be configured by the network device 120 to characterize the transmit power distribution across layers. For example, the terminal device 110 may be configured to allocate PDSCH power such that the minimum per- layer SINR, within a same codeword or across multiple codewords, is maximized. This transmit power allocation yields equal SINR across layers and can be used, for example, to facilitate rank override at the network device 120.

[0069] In some embodiments, there is a configuration whereby the terminal device 110 assumes transmitpower allocation to maximize throughput for a single codeword or across multiple codewords. This power allocation results in a water-filling power allocation across layers and / or codewords. If the terminal device 110 is configured to assume unequal power allocation across layers and / or codewords and / or frequency subbands, the terminal device may need to report the distribution of PDSCH transmit power across theconfigured resources. For example, in case of unequal distribution across the ^^ reported layers, theterminal device 110 may report ^^ − 1 real values, ^^^^ ≤ 1, for ^^ = 1, … , ^^ − 1 representing the fractionof PDSCH power allocated to layer ^^, such that ^^^^ = 1 −.

[0070] In some embodiments, the CSI calculation is also performed with power back-off. For example, theterminal device 110 can be configured to assume that the PDSCH transmit power is reduced by a back-off factor, i.e., instead of assuming a transmit power per subcarrier of ^^^^^^as determined from the configuredPc ratio, the terminal device 110 assumes a lower transmit power of ^^^^^^^^, with ^^ ≤ 1, in linear scale,where the back-off factor ^^ may be calculated and reported by the UE, or defined by a formula that depends on the precoding matrix and the power distribution across layers, or may be configured by the network device 120.

[0071] In some embodiments, the terminal device 110 transmits the CSI report 340 including powerallocation indication across layers. The indication of the transmit power allocation comprises at least one value representing a power ratio between a power allocated to a resource in the group of resources over a total transmit power across the group of resources.

[0072] In some embodiments, the terminal device 110 transmits to the network device 120, an indicationof a transmit power back-off based at least in part on the maximum transmit power per CSI-RS port. The back-off is a ratio between a total transmit power that satisfies the limitation of transmit power per CSI-RS port and a configured transmit power. For example, the CSI report also includes power back-off indication.

[0073] The network device 120 performs 350 the PMI reconstruction and precoder calculation. And thenetwork device 120 transmits the PDSCH transmission 360 based on the precoder.

[0074] In some embodiment, the network device 120 can configure the terminal device 110 for CSIcalculation to assume that the total PDSCH transmit power is distributed across at least a group of layers, according to one, or more than one, predefined criteria. Examples of configurable criteria for unequal power allocation across layers are to target equal SINRs for all layers in a same group, or to maximize the sum-rate (i.e., water-filling power allocation). The layer group may comprise the layers to which a same codeword is (or can be) mapped. The terminal device 110 can be configured to report an indication of the fraction of total transmit power allocated to each layer in a layer group, for each of the configured criteria. The sum of the fractional power allocation indicators may be fixed, for example, to one or it can be configured or reported asa value ^^ ≤ 1, in case transmit power back-off is assumed.

[0075] FIG. 4 illustrates an example of water-filling power allocation across layers according to someembodiments of the present disclosure. Specifically, in this example of optimized power distribution assumption across layers or group of layers, the UE may be configured to assume a power allocation that maximize the sum-rate across layers, i.e., a water-filling type of power allocation. In this case, the UE may assume the following power distribution, whereis the “water level” and [⋅]+indicates that only positive power values are taken. If a power value is negative, the rank needs to be reduced

[0076] Note that in the special case of balanced layers with equal eigenvalues, the water-filling powerallocation boils down to equal power allocation with ^^^^ = ^^^^^^ / ^^.

[0077] As shown in FIG.4, the UE calculates the power distribution and obtains the fractions of transmitpower, ^^^^ ≤ 1, ^^ = 1, … , ^^, to allocate to the reported ^^ layers. The ^^^^ values may be calculated asfollows according to the derivation above 1, … , ^^where is the “water level”, such that= 1. The UE then reports ^^ − 1 such values, forexample, the portions of power assigned to the first ^^ − 1 layers.

[0078] In some embodiment, the power ratio is reported for the resources in the group of resourcesseparately, except for one resource in the group of resource, and a sum of power ratios of all the resources in the group is a fixed or reported value. For example, because the sum of these fractional power allocation is fixed to 1, the portion of power allocated to the ^^-th layer does not need to be reported and can be obtainedfrom the other ^^ − 1 reported values. In this example, the UE is configured to maximize the throughput(i.e., sum-rate) or CQI across a group of layers, for example mapped to a same codeword, under the assumption of total transmit power constraint and unequal power distribution across the layers. The reported transmit power split achieves unequal per-layer SINR and CQI, hence it may not be suitable in case of rank override by the gNB.

[0079] FIG.5 illustrates an example of power allocation for equal SINRs across layers according to someembodiments of the present disclosure. Specifically, in this example of optimized power distribution assumption across layers or a group of layers, the UE may be configured to assume a power allocation that maximizes fairness across layers, i.e., it maximizes the minimum SINR across layers, i.e., it achieves equal SINR for all layers. In this case, the UE may assume the following power allocation

[0080] Note that in the special case of balanced layers with equal eigenvalues, the power allocation thatachieves equal SINRs boils down to equal power allocation with ^^^^ = ^^^^^^ / ^^.

[0081] Whilst the legacy equal power allocation assumption causes SINR imbalances between layers, byachieving the following SINRsthe other two power allocation strategies mitigate the layer imbalance by achieving, for the water-filling allocation the following SINRs ^^^^^^^^^^ = [^^^^^^ − 1]+, ^^ = 1, … , ^^and rate per layer [log(^^^^^^)]+, ^^ = 1, … , ^^

[0082] The power allocation that yields equal SINR per layer achieves the following SINR

[0083] As shown in FIG.5, the UE calculates the power distribution and obtains the fractions of transmitpower, ≤ 1, ^^ = 1, … , ^^, to allocate to the reported ^^ layers. The ^^^^ values may be calculatedfollows according to the derivation abovewhere = 1. Note that, unlike the water-filling power allocation, the power per layer isproportional to the corresponding eigenvalue, hence weaker layers receive more power to boost SINR to thesame level as stronger layers. The UE then reports ^^ − 1 such values, for example, the portions of powerassigned to the first ^^ − 1 layers. Because the sum of these fractional power allocation is fixed to 1, theportion of power allocated to the ^^-th layer does not need to be reported. In this example, a UE is configured to maximize the minimum per-layer SINR or CQI for a group of layers, for example mapped to a same codeword, under the assumption of total transmit power constraint and unequal power distribution across the layers. The reported transmit power split achieves equal per-layer SINR and CQI, hence it may be suitable in case of rank override by the gNB.

[0084] FIG. 6 illustrates an example of maximum per-antenna transmit power with water-filling powerallocation according to some embodiments of the present disclosure. In some embodiments, the UE receives information of a maximum transmit power per CSI-RS port for the PDSCH. The UE determines the at least one CSI quantity, based on an equal distribution of transmit power across the CSI-RS port.

[0085] Specifically, in this example, the UE can be configured to assume a maximum PDSCH transmitpower per antenna, ^^^^^^ / ^^^^^^, for a CSI calculation with unequal power allocation. In this case, the UE reports the power split across layers as well as any transmit power penalty due to unequal power allocation across transmit antennas. Note that, if the PMI is calculated by the UE such that the power per antenna is the same for all antenna ports, there is no power penalty.

[0086] For example, the UE implementation where the PMI is not optimized such that the power perantenna port is the same for all antenna ports. The UE allocates the transmit power across layers according to one of the strategies such as max throughput or max-min per-layer SINR, and applies a power back-offfactor ^^ ≤ 1 such that the precoding matrix for a generic subband, after power allocation and back-off canbe written as ^^ = ^^^^^^^^^^(√^^)√^^

[0087]

[0088] The back-off factor can be calculated aswhich is the ratio between the average power per transmit antenna port over the maximum power per transmitantenna port. The adjusted power distribution factors: ^^1, … ,^^^^ are such that their sum equals the back-off factor, i.e.

[0089] The back-off factor, ^^ , may be calculated by the UE and reported alongside ^^ − 1 powerdistribution factors ^^1, …such that the ^^-th power distribution factor is obtained as: ^^^^ = ^^ −A maximum back-off factor may also be fixed or pre-configured by the network such that the UE is expected to calculate a CSI such that it does not exceed such maximum value.

[0090] As shown in FIG.6, the gNB configures the total power, per-antenna maximum transmit power andwater-filling power application across a group layers for the UE. The UE calculates the transmit power allocation across layers based on the configuration. And the UE reports CSI including power back-offindication ^^ and power allocation indication ^^1, … ,^^^^−1.

[0091] FIG. 7 illustrates an example of maximum per-antenna transmit power with power allocation forequal SINRs across layers according to some embodiments of the present disclosure.

[0092] As shown in FIG.7, the gNB configures the total power, per-antenna maximum transmit power andpower allocation across a group layers targeting equal SINR per layer for the UE. The UE calculates the transmit power allocation across layers based on the configuration. And the UE reports CSI including powerback-off indication ^^ and power allocation indication ^^1, … ,^^^^−1.

[0093] In some embodiment, the UE receives information of at least one power allocation hypothesis. Andthe UE determines the at least one CSI quantity based on the at least one power allocation hypothesis. The UE transmits to the network device, if needed, a third indication indicates the selected at least one hypothesis along with corresponding at least one CSI quantity. For example, if a UE is configured / indicated or specified to report multiple CQIs under different target power distribution and / or per-antenna maximum transmit power assumptions, these different power allocation hypotheses may lead to different rank assumptions and consequently different mapping of layers to codewords. Therefore, each power allocation indication may bereported, in some cases, with at least a corresponding CQIs and rank indication. Note that in the description of some embodiments of the application, the following terminology is used to distinguish different elements of a configuration related to power allocation: a power allocation type refers, for example, to equal or unequal power allocation; a power allocation target refers, for example, to equal SINR across layers, or max CQI or throughput per codeword, etc.; a power allocation hypothesis comprises all configuration elements defining a power configuration associated to a CSI calculation, for example, a power allocation hypothesis may configure unequal power allocation type, with target of maximum throughput across reported layers of a codeword.

[0094] In some embodiments, the power allocation hypothesis includes a power allocation target, at leastone power back-off value, or multiple sets of resources. The multiple power allocation hypotheses are configured and at least one CSI quantity is determined for the power allocation hypotheses separately. The UE selects the at least one power allocation hypothesis based on at least one condition for the CSI quantity corresponds to the at least one power allocation hypothesis.

[0095] In some embodiments, the UE receives, from the network device, information of at least one targetfor the power allocation. The target for the power allocation includes an equal SINR, or a CQI, across reported layers of each codeword, an equal SINR or a CQI across reported codewords, or a maximum sum throughput of reported codewords.

[0096] In view of the above description of the various embodiments of the present disclosure, theseembodiments of the present disclosure provide the advantage of solving the inconsistencies issues of layer imbalance power allocating and transmit power back-off when per-antenna maximum transmit power is exceeded. Then the performance of communication with transmit power allocation is improved.

[0097] FIG. 8 shows a flowchart of an example method 800 implemented at a terminal device inaccordance with some embodiments of the present disclosure. For the purpose of discussion, the method 800 will be described from the perspective of the terminal device 110 with reference to FIG.1A.

[0098] At block 810, the terminal device 110 obtains, a CSI, configuration including an indication of at leastone type of allocation of transmit power across at least one group of resources for a PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. At block 820, the terminal device 110 determines, at least one CSI quantity, based on the indication of at least one type of allocation of transmit power across the at least one group of resources for the PDSCH. At block 830, the terminal device 110 transmits, to a network device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

[0099] In some embodiments, the at least one first indication of the transmit power allocation comprisesat least one value representing a power ratio between a power allocated to a resource in the group of resources over a total transmit power across the group of resources. the power ratio is reported for theresources in the group of resources separately, except for one resource in the group of resource, and a sum of power ratios of all the resources in the group is a fixed or reported value

[0100] In some embodiments, the terminal device 110 receives, information of a maximum transmit powerper CSI-RS, port for the PDSCH. The terminal device 110 determines, the at least one CSI quantity, based on an equal distribution of transmit power across the CSI-RS ports. The terminal device 110 transmits, to the network device, a second indication of a transmit power back-off based at least in part on the maximum transmit power per CSI-RS port. The second indication of transmit power back-off is a ratio between a total transmit power that satisfies the limitation of transmit power per CSI-RS port and a configured transmit power. The second indication of transmit power back-off is equal to the sum of power ratios of the first indication across all the resources in the group.

[0101] In some embodiments, the terminal device 110 receives, information of at least one power allocationhypothesis. And the terminal device 110 determines, the at least one CSI quantity based on the at least one power allocation hypothesis. The terminal device 110 transmits, to the network device, a third indication indicates the selected at least one hypothesis along with corresponding at least one CSI quantity in case of the third indication is required for the network device. The at least one power allocation hypothesis includes at least one of a power allocation target, at least one power back-off value, or multiple sets of resources.

[0102] In some embodiments, multiple power allocation hypotheses are configured and at least one CSIquantity is determined for the power allocation hypotheses separately. The terminal device 110 selects the at least one power allocation hypothesis based on at least one condition for the CSI quantity corresponding to the at least one power allocation hypothesis. The terminal device 110 receives, from the network device, information of at least one target for the power allocation. The target for the power allocation includes at least one of an equal signal to interference plus noise ratio, SINR, or a channel quality indication, CQI, across layers of each of at least one codeword, an equal SINR or a CQI across codewords, or a maximum sum throughput of codewords. The group of resources comprise at least one of a layer, a group of layers, a subband, a group of subbands, a codeword, a TRP.

[0103] FIG. 9 shows a flowchart of an example method 900 implemented at a network device inaccordance with some embodiments of the present disclosure. For the purpose of discussion, the method 900 will be described from the perspective of the network device 120 with reference to FIG.1A.

[0104] At block 910, the network device 120 transmits transmit, to a terminal device, a CSI, configurationincluding an indication of at least one type of allocation of transmit power across at least one group of resources for a PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. At block 920, the network device 120 receives, from the terminal device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

[0105] In some embodiments, the at least one first indication of the transmit power allocation comprisesat least one value representing a power ratio between a power allocated to a resource in the group of resources over a total transmit power across the group of resources. The power ratio is reported for the resources in the group of resources separately, except for one resource in the group of resource, and a sum of power ratios of all the resources in the group is a fixed or reported value. The network device 120 transmits, information of a maximum transmit power per CSI-RS, port for the PDSCH.

[0106] In some embodiments, the network device 120 receives, from the terminal device, a secondindication of a transmit power back-off based at least in part on the maximum transmit power per CSI-RS port. The second indication of transmit power back-off is a ratio between a total transmit power that satisfies the limitation of transmit power per CSI-RS port and a configured transmit power. The second indication of transmit power back-off is equal to the sum of power ratios of the first indication across all the resources in the group.

[0107] In some embodiments, the network device 120 transmits, information of at least one powerallocation hypothesis. The network device 120 receives, a third indication indicates the selected at least one hypothesis along with corresponding at least one CSI quantity. The at least one power allocation hypothesis includes at least one of a power allocation target, at least one power back-off value, or multiple sets of resources. Multiple of the power allocation hypotheses are configured and at least one CSI quantity is determined for each of the power allocation hypotheses.

[0108] In some embodiments, the network device transmits, information of at least one target for the powerallocation. The target for the power allocation includes at least one of an equal signal to interference plus noise ratio, SINR, or a channel quality indication, CQI, across layers of each of at least one codeword, an equal SINR or a CQI across codewords, or a maximum sum throughput of codewords. The group of resources comprise at least one of a layer, a group of layers, a subband, a group of subbands, a codeword, a TRP.

[0109] In some embodiments, an apparatus capable of performing any of the method 800 (for example,the terminal device 110) may comprise means for performing the respective steps of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0110] In some embodiments, the apparatus comprises means for obtaining, a CSI, configuration includingan indication of at least one type of allocation of transmit power across at least one group of resources for a PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. The apparatus comprises means for determining, at least one CSI quantity, based on the indication of at least one type of allocation of transmit power across the at least one group of resources for the PDSCH. The apparatus comprises means for transmitting, to a network device, at least one first indication indicatinga transmit power allocation across the at least one group of resources for the PDSCH.

[0111] In some embodiments, the at least one first indication of the transmit power allocation comprisesat least one value representing a power ratio between a power allocated to a resource in the group of resources over a total transmit power across the group of resources. the power ratio is reported for the resources in the group of resources separately, except for one resource in the group of resource, and a sum of power ratios of all the resources in the group is a fixed or reported value

[0112] In some embodiments, the apparatus comprises means for receiving, information of a maximumtransmit power per CSI-RS, port for the PDSCH. The apparatus comprises means for determining, the at least one CSI quantity, based on an equal distribution of transmit power across the CSI-RS ports. The apparatus comprises means for transmitting, to the network device, a second indication of a transmit power back-off based at least in part on the maximum transmit power per CSI-RS port. The second indication of transmit power back-off is a ratio between a total transmit power that satisfies the limitation of transmit power per CSI-RS port and a configured transmit power. The second indication of transmit power back-off is equal to the sum of power ratios of the first indication across all the resources in the group.

[0113] In some embodiments, the apparatus comprises means for receiving, information of at least onepower allocation hypothesis. The apparatus comprises means for determining, the at least one CSI quantity based on the at least one power allocation hypothesis. The apparatus comprises means for transmitting, to the network device, a third indication indicates the selected at least one hypothesis along with corresponding at least one CSI quantity in case of the third indication is required for the network device. The at least one power allocation hypothesis includes at least one of a power allocation target, at least one power back-off value, or multiple sets of resources.

[0114] In some embodiments, multiple power allocation hypotheses are configured and at least one CSIquantity is determined for the power allocation hypotheses separately. The apparatus comprises means for selecting the at least one power allocation hypothesis based on at least one condition for the CSI quantity corresponding to the at least one power allocation hypothesis. The apparatus comprises means for receiving, from the network device, information of at least one target for the power allocation. The target for the power allocation includes at least one of an equal signal to SINR, or a CQI, across layers of each of at least one codeword, an equal SINR or a CQI across codewords, or a maximum sum throughput of codewords. The group of resources comprise at least one of a layer, a group of layers, a subband, a group of subbands, a codeword, a TRP.

[0115] In some embodiments, an apparatus capable of performing any of the method 900 (for example,the network device 120) may comprise means for performing the respective steps of the method 900. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0116] In some embodiments, the apparatus comprises means for transmitting transmit, to a terminaldevice, a CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation. The apparatus comprises means for receiving, from the terminal device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

[0117] In some embodiments, the at least one first indication of the transmit power allocation comprisesat least one value representing a power ratio between a power allocated to a resource in the group of resources over a total transmit power across the group of resources. The power ratio is reported for the resources in the group of resources separately, except for one resource in the group of resource, and a sum of power ratios of all the resources in the group is a fixed or reported value. The apparatus comprises means for transmitting, information of a maximum transmit power per CSI-RS, port for the PDSCH.

[0118] In some embodiments, the apparatus comprises means for receiving, from the terminal device, asecond indication of a transmit power back-off based at least in part on the maximum transmit power per CSI-RS port. The second indication of transmit power back-off is a ratio between a total transmit power that satisfies the limitation of transmit power per CSI-RS port and a configured transmit power. The second indication of transmit power back-off is equal to the sum of power ratios of the first indication across all the resources in the group.

[0119] In some embodiments, the apparatus comprises means for transmitting, information of at least onepower allocation hypothesis. The apparatus comprises means for receiving, a third indication indicates the selected at least one hypothesis along with corresponding at least one CSI quantity. The at least one power allocation hypothesis includes at least one of a power allocation target, at least one power back-off value, or multiple sets of resources. Multiple of the power allocation hypotheses are configured and at least one CSI quantity is determined for each of the power allocation hypotheses.

[0120] In some embodiments, the apparatus comprises means for transmitting, information of at least onetarget for the power allocation. The target for the power allocation includes at least one of an equal signal to SINR, or a CQI, across layers of each of at least one codeword, an equal SINR or a CQI across codewords, or a maximum sum throughput of codewords. The group of resources comprise at least one of a layer, a group of layers, a subband, a group of subbands, a codeword, a TRP.

[0121] FIG.10 is a simplified block diagram of a device 1000 that is suitable for implementing embodimentsof the present disclosure. The device 1000 may be provided to implement the communication device, for example the terminal device 110, the network device 120 as shown in FIG.1A. As shown, the device 1000 includes one or more processors 1010, one or more memories 1020 coupled to the processor 1010, and one or more communication modules 1040 coupled to the processor 1010.

[0122] The communication module 1040 is for bidirectional communications. The communicationmodule 1040 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

[0123] The processor 1010 may be of any type suitable to the local technical network and may includeone or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1000 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0124] The memory 1020 may include one or more non-volatile memories and one or more volatilememories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1024, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 1022 and other volatile memories that will not last in the power-down duration.

[0125] A computer program 1030 includes computer executable instructions that are executed by theassociated processor 1010. The program 1030 may be stored in the ROM 1024. The processor 1010 may perform any suitable actions and processing by loading the program 1030 into the RAM 1022.

[0126] The embodiments of the present disclosure may be implemented by means of the program 1030so that the device 1000 may perform any process of the disclosure as discussed with reference to FIGS.2 to 9. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0127] In some embodiments, the program 1030 may be tangibly contained in a computer readablemedium which may be included in the device 1000 (such as in the memory 1020) or other storage devices that are accessible by the device 1000. The device 1000 may load the program 1030 from the computer readable medium to the RAM 1022 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. FIG.11 shows an example of the computer readable medium 1100 in form of CD or DVD. The computer readable medium has the program 1030 stored thereon.

[0128] Generally, various embodiments of the present disclosure may be implemented in hardware orspecial purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method describedherein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0129] The present disclosure also provides at least one computer program product tangibly stored on anon-transitory computer readable storage medium. The computer program product includes computer- executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the methods 800-900 as described above with reference to FIGS.8-9. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0130] Program code for carrying out methods of the present disclosure may be written in any combinationof one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0131] In the context of the present disclosure, the computer program codes or related data may be carriedby any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0132] The computer readable medium may be a computer readable signal medium or a computerreadable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. 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).

[0133] Further, while operations are depicted in a particular order, this should not be understood asrequiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub- combination.

[0134] Although the present disclosure has been described in languages specific to structural featuresand / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

WHAT IS CLAIMED IS:

1. A terminal device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: obtain, a channel state information, CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation; determine, at least one CSI quantity, based on the indication of at least one type of allocation of transmit power across the at least one group of resources for the PDSCH; and transmit, to a network device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

2. The terminal device of claim 1, wherein the at least one first indication of the transmit power allocation comprises at least one value representing a power ratio between a power allocated to a resource in the group of resources over a total transmit power across the group of resources.

3. The terminal device of claim 2, wherein the power ratio is reported for the resources in the group of resources separately, except for one resource in the group of resource, and a sum of power ratios of all the resources in the group is a fixed or reported value.

4. The terminal device of any of claims 1-3, wherein the terminal device is further caused to: receive, information of a maximum transmit power per channel state information reference signal, CSI-RS, port for the PDSCH; and determine, the at least one CSI quantity, based on an equal distribution of transmit power across the CSI-RS ports.

5. The terminal device of claim 4, wherein the terminal device is further caused to: transmit, to the network device, a second indication of a transmit power back-off based at least in part on the maximum transmit power per CSI-RS port.

6. The terminal device of claim 5, wherein the second indication of transmit power back-off is a ratio between a total transmit power that satisfies the limitation of transmit power per CSI-RS port and a configured transmit power.

7. The terminal device of claim 5, wherein the second indication of transmit power back-off is equal to the sum of power ratios of the first indication across all the resources in the group.

8. The terminal device of any of claims 1-7, wherein the terminal device is further caused to: receive, information of at least one power allocation hypothesis; determine, the at least one CSI quantity based on the at least one power allocation hypothesis; and transmit, to the network device, a third indication indicates the selected at least one hypothesis along with corresponding at least one CSI quantity in case of the third indication is required for the network device.

9. The terminal device of claim 8, wherein the at least one power allocation hypothesis includes at least one of the following: a power allocation target; at least one power back-off value; or multiple sets of resources.

10. The terminal device of claim 8, wherein the terminal device is further caused to: select the at least one power allocation hypothesis based on at least one condition for the CSI quantity corresponding to the at least one power allocation hypothesis.

11. The terminal device of claim 9, wherein the target for the power allocation includes at least one of the following: an equal signal to interference plus noise ratio, SINR, or a channel quality indication, CQI, across layers of each of at least one codeword; an equal SINR or a CQI across codewords; or a maximum sum throughput of codewords.

12. The terminal device of any of claims 1-11, wherein the group of resources comprise at least one of a layer, a group of layers, a subband, a group of subbands, a codeword, a transmission-reception point, TRP.

13. A network device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to:transmit, to a terminal device, a channel state information, CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation; and receive, from the terminal device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

14. The network device of claim 13, wherein the at least one first indication of the transmit power allocation comprises at least one value representing a power ratio between a power allocated to a resource in the group of resources over a total transmit power across the group of resources.

15. The network device of claim 13 or 14, wherein the network device is further caused to: transmit, information of a maximum transmit power per channel state information reference signal, CSI-RS, port for the PDSCH.

16. A method comprising: obtaining, a channel state information, CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation; determining, at least one CSI quantity, based on the indication of at least one type of allocation of transmit power across the at least one group of resources for the PDSCH; and transmitting, to a network device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

17. A method comprising: transmitting, to a terminal device, a channel state information, CSI, configuration including an indication of at least one type of allocation of transmit power across at least one group of resources for a physical downlink shared channel, PDSCH and where the at least one type of transmit power allocation comprises equal or unequal power allocation; and receiving, from the terminal device, at least one first indication indicating a transmit power allocation across the at least one group of resources for the PDSCH.

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