Beam power boosting

Abstract

Example embodiments of the present disclosure are directed to beam power boosting A method comprises receiving, from a second apparatus, a channel state information (CSI) report configuration at least including transmit power restriction information of beams associated with a CSI report; re-allocating respective transmit power of a plurality of selected beams by restricting respective reference transmit powers of a group of beams from the plurality of selected beams based on the transmit power restriction information and increasing respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams; and transmitting the CSI report to the second apparatus based on the re-allocation.

Description

BEAM POWER BOOSTINGCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority from, and the benefit of, US Provisional Application No. 63 / 706984, filed October 14, 2024, which is hereby incorporated by reference in its entirety.FIELD

[0002] Various example embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to methods, devices, apparatuses and computer readable storage medium for beam power boosting.BACKGROUND

[0003] Limits are introduced to the expected effective isotropic radiated power (EIRP) spectral density within the frequency band 6425-7125 MHz for different ranges of elevation angles above the horizon.

[0004] These radiated power limits are intended to control interference between terrestrial mobile services (IMT) and fixed satellite services (FSS) (Earth-to-space) such that they can coexist in the same frequency band.SUMMARY

[0005] In a first aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: receive, from a second apparatus, a channel state information, CSI, report configuration at least including transmit power restriction information of beams associated with a CSI report; re-allocate respective transmit power of a plurality of selected beams by restricting respective reference transmit powers of a group of beams from the plurality of selected beams based on the transmit power restriction information and increasing respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams; and transmit the CSI report to the second apparatus based on the re-allocation.

[0006] In a second aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: transmit, to a first apparatus, a channel state information, CSI, configuration at least including transmit power restriction information of beams associated with a CSI report; receive the CSI report from the first apparatus; and perform a downlink data transmission at least based on the CSI report.

[0007] In a third aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: reduce, based on a transmit power restriction, respective reference transmit powers of a group of beams from a plurality of selected beams; increase respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams; and transmit, to the second apparatus, a CSI report at least indicating an order of the one or more beams with respective transmit power increases.

[0008] In a fourth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: receive, from a first apparatus, a CSI report at least indicating an order of one or more beams with respective transmit power increases, wherein the one or more beams are from remaining beams in a plurality of selected beams other than a group of beams on which respective reference transmit powers are restricted; and perform a downlink data transmission at least based on the CSI report.

[0009] In a fifth aspect of the present disclosure, there is provided a method. The method comprises: receiving, from a second apparatus, a channel state information, CSI, report configuration at least including transmit power restriction information of beams associated with a CSI report; reallocating respective transmit power of a plurality of selected beams by restricting respective reference transmit powers of a group of beams from the plurality of selected beams based on the transmit power restriction information and increasing respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams; and transmitting the CSI report to the second apparatus based on the re-allocation.

[0010] In a sixth aspect of the present disclosure, there is provided a method. The method comprises: transmitting, to a first apparatus, a channel state information, CSI, configuration at least including transmit power restriction information of beams associated with a CSI report; receiving the CSI report from the first apparatus; and performing a downlink data transmission at least based on the CSI report.

[0011] In a seventh aspect of the present disclosure, there is provided a method. The method comprises: reducing, based on a transmit power restriction, respective reference transmit powers of a group of beams from a plurality of selected beams; increasing respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams; and transmitting, to the second apparatus, a CSI report at least indicating an order of the one or more beams with respective transmit power increases.

[0012] In an eighth aspect of the present disclosure, there is provided a method. The methodcomprises: receiving, from a first apparatus, a CSI report at least indicating an order of one or more beams with respective transmit power increases, wherein the one or more beams are from remaining beams in a plurality of selected beams other than a group of beams on which respective reference transmit powers are restricted; and performing a downlink data transmission at least based on the CSI report.

[0013] In a ninth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for receiving, from a second apparatus, a channel state information, CSI, report configuration at least including transmit power restriction information of beams associated with a CSI report; means for re-allocating respective transmit power of a plurality of selected beams by restricting respective reference transmit powers of a group of beams from the plurality of selected beams based on the transmit power restriction information and increasing respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams; and means for transmitting the CSI report to the second apparatus based on the re-allocation.

[0014] In a tenth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for transmitting, to a first apparatus, a channel state information, CSI, configuration at least including transmit power restriction information of beams associated with a CSI report; means for receiving the CSI report from the first apparatus; and means for performing a downlink data transmission at least based on the CSI report.

[0015] In an eleventh aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for reducing, based on a transmit power restriction, respective reference transmit powers of a group of beams from a plurality of selected beams; means for increasing respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams; and means for transmitting, to the second apparatus, a CSI report at least indicating an order of the one or more beams with respective transmit power increases.

[0016] In a twelfth aspect of the present disclosure, there is provided a second apparatus. The first apparatus comprises means for receiving, from a first apparatus, a CSI report at least indicating an order of one or more beams with respective transmit power increases, wherein the one or more beams are from remaining beams in a plurality of selected beams other than a group of beams on which respective reference transmit powers are restricted; and means for performing a downlink data transmission at least based on the CSI report.

[0017] In a thirteenth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the fifth aspect.

[0018] In a fourteenth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the sixth aspect.

[0019] In a fifteenth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the seventh aspect.

[0020] In a sixteenth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the eighth aspect.

[0021] It is to be understood that the Summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0023] FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

[0024] FIG. 2 illustrates an example process in calculating the expected EIRP spectral density of an IMT base station;

[0025] FIG. 3 illustrates a signaling chart of communication according to some example embodiments of the present disclosure;

[0026] FIG. 4 illustrates a signaling chart of communication according to some example embodiments of the present disclosure;

[0027] FIGS. 5A and 5B illustrate examples of a CSI report configuration without and with transmit power restriction on beamforming according to some example embodiments of the present disclosure;

[0028] FIG. 6 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0029] FIG. 7 illustrates a flowchart of a method implemented at a second apparatus in accordance with some example embodiments of the present disclosure;

[0030] FIG. 8 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0031] FIG. 9 illustrates a flowchart of a method implemented at a second apparatus in accordance with some example embodiments of the present disclosure;

[0032] FIG. 10 illustrates a simplified block diagram of a device that is suitable for implementingexample embodiments of the present disclosure; and

[0033] FIG. 11 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

[0034] Throughout the drawings, the same or similar reference numerals represent the same or similar element.DETAILED DESCRIPTION

[0035] Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

[0036] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0037] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0038] It shall be understood that although the terms “first,” “second,”..., etc. in front of noun(s) and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another and they do not limit the order of the noun(s). For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0039] 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.

[0040] As used herein, unless stated explicitly, performing a step “in response to A” does not indicate that the step is performed immediately after “A” occurs and one or more intervening stepsmay be included.

[0041] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used 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.

[0042] 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.

[0043] 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.

[0044] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE- A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-loT) 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 (1 G),the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the fifth generation (5G), 5.5G, the sixth generation (6G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future types of 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.

[0045] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (I AB) node, a low power node such as a femto, a pico, a non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft network device, and so forth, depending on the applied terminology and technology. In some example embodiments, radio access network (RAN) split architecture comprises a Centralized Unit (CU) and a Distributed Unit (DU) at an IAB donor node. An IAB node comprises a Mobile Terminal (IAB-MT) part that behaves like a UE toward the parent node, and a DU part of an IAB node behaves like a base station toward the next-hop IAB node.

[0046] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. The terminal device may also correspond to a Mobile Termination (MT) part of an IAB node (e.g., a relay node). In the following description, the terms “terminal device”,“communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0047] As used herein, the term “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other combination of the time, frequency, space and / or code domain resource enabling a communication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

[0048] FIG. 1 illustrates an example communication environment 100 in which example embodiments of the present disclosure can be implemented. As shown in FIG. 1 , the communication network 100 may comprise a first apparatus 110 which may be, for example, a terminal device. In some example embodiments, the terminal device may also be discussed as a UE.

[0049] The communication network 100 may further comprise a second apparatus 120, which may be, for example, a network device. In some example embodiments, the network device may be discussed as a BS, a gNB, or an eNB.

[0050] A serving area provided by the second apparatus 120 is called a cell. The first apparatus 110 may communicate with the second apparatus 120 within the cell 102. The cell currently serving the first apparatus 110 may be considered as a serving cell 102.

[0051] In the following, for the purpose of illustration, some example embodiments are described with the first apparatus 110 operating as a terminal device and the second apparatus 120 operating as a network device. However, in some example embodiments, operations described in connection with a terminal device may be implemented at a network device or other device, and operations described in connection with a network device may be implemented at a terminal device or other device.

[0052] In some example embodiments, if the first apparatus 110 is a terminal device and second apparatus 120 is a network device, a link from the second apparatus 120 to first apparatus 110 is referred to as a downlink (DL), while a link from the first apparatus 110 to second apparatus 120 is referred to as an uplink (UL). In DL, the second apparatus 120 is a transmitting (TX) apparatus (or a transmitter) and the first apparatus 110 is a receiving (RX) apparatus (or a receiver). In UL, the first apparatus 110 is a TX apparatus (or a transmitter) and the second apparatus 120 is a RX apparatus (or a receiver).

[0053] It is to be understood that the number of network devices and terminal devices shown in FIG.1 is given for the purpose of illustration without suggesting any limitations. The communicationenvironment 100 may include any suitable number of network devices and terminal devices.

[0054] Communications in the communication environment 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1 G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G), 5.5G, the sixth generation (6G), and the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0055] As described above, limits are introduced to the expected effective isotropic radiated power (El RP) spectral density for different ranges of elevation angles above the horizon. These radiated power limits are intended to control interference between terrestrial mobile services (IMT) and fixed satellite services (FSS) (Earth-to-space) such that they can coexist in the same frequency band.

[0056] The expected EIRP mask sets a regulatory limit on the expected EIRP within each vertical (elevation) angle (0) window at or above the horizon (O° < O < 90°). The proposed expected EIRP mask is accompanied with specific “Notes" which clearly define the statistical expectation (averaging) process and state the stochastic parameters involved in the expectation process. The “Notes" are used to define explicit conditions required for verification of the derived expected EIRP limits, ensuring that the defined limits are clear and cannot be misinterpreted.

[0057] An association between different ranges of elevation angles above the horizon and related expected EIRP is listed as below: Table 1NOTE 1 : The expected e.i.r.p. is defined as the average value of the e.i.r.p., with the averaging being performed: over horizontal angles from -180°to +180°, with the IMT base station beamforming in a specific direction within its horizontal and vertical steering range, over different beamforming directions within the IMT base station horizontal and vertical steering range, and over the specified vertical angle range OL 0 < OH.NOTE 2: An IMT base station shall comply with the specified limits on expected e.i.r.p. spectral density for all mechanical tilts with which it can be deployed.

[0058] The expectation process in calculating the expected EIRP spectral density of an IMT base station is over the horizontal angles, beamforming directions and vertical (elevation) angle windows as illustrated in FIG. 2. The EIRP of an IMT base station in the horizontal (azimuth) direction - IT < cp < IT and vertical (elevation) direction 0 < 0 < TT / 2 above the horizon can be written as P (0, cp; a, 0). The parameters a and p are the horizontal and vertical beamforming directions, i.e. the angles towards which the base station electronically steers a beam.

[0059] For active antenna system base stations within a given horizontal and vertical steering range, averaging over beamforming directions for a given vertical angle 9o and horizontal angle q>o the expectation of the EIRP spectral density is obtained by averaging over a sufficient sampling of N beamforming directions (an, n) n = 1 ... N.

[0060] The beamforming directions (an, Pn) have a uniform statistical angular distribution within the steering range of the IMT base station. In other words:where the EIRP spectral densities are in units of mW / MHz and i / i / nrefers to the weight for the n-th beamforming direction, i.e. the fraction of the steering range represented by the n-th beamforming direction. For example, i / i / n= 1 / A / in the case that N uniform equispaced beams are assumed in the azimuth and elevation, respectively, and where each beam covers an equal range of angles.

[0061] Each beam direction can be associated with a downlink transmission of any supported rank, therefore the maximum allowed transmit power per layer depends on the number of layers transmitted in the same beam direction.

[0062] It was agreed to support a 3-bit power scaling configuration for Type-I Channel State Information (CSI) reporting for up to 128 ports, and for rank 1 , where the configured power scaling factor Si for Spatial domain (SD) basis (i.e. discrete Fourier transform (DFT) beam) i applies to the PDSCH power, Ptx, such that the power per layer assumed by the UE for Channel Quality Indication(CQI) calculation is Ptx■ s , if the SD basis of index i is selected for the rank-1 precoder matrix indicator (PMI). Note that the PDSCH power is configured per CSI-reference signal (RS) resource by the physical downlink shared channel (PDSCH)-to-CSI-RS EPRE offset (or power control ratio).

[0063] For ranks larger than 1 , a layer-group with r£layers may be mapped to a selected beam of index i, where r£e {1,2}. The fraction of PDSCH power allocated to a layer mapped to a beam without any transmit power restriction is 1 / v, for a rank-u PMI, which corresponds to a power scaling factor per layer of 1 . If the beam is power restricted, then the maximum fraction of transmit power per layer for that beam cannot exceed Si / ritwhich corresponds to a power scaling factor per layer of sf ■ v / rt. Therefore, to fulfil the max transmit power per beam, a UE applies a power scaling factor per layer given by min [l, s / • -]. Note that applying a power scaling factor per layer given by ri ' min | l, s / - -| is equivalent to a transmit power per layer given by min i-,— | because each layer l r£J tv r£J is already normalised by 1 / v in a typical PMI definition.

[0064] The main use case for introducing per-beam transmit power back-off is to meet the expected EIRP spectral density limits at elevation angles above the horizon to control interference between mobile terrestrial and fixed satellite services. However, one drawback of this configured power backoff is that, if a UE selects one or more power-restricted beams, depending on the rank of the reported CSI, the resulting PDSCH transmit power may be lower than that configured by the PDSCH-to-CSI- RS EPRE. This power penalty can result in performance degradation as the UE calculates the CQI assuming a PDSCH transmit power that is lower than that configured by the network.

[0065] In accordance with some example embodiments of the present disclosure, there is provided a solution for beam power boosting. In this solution, a CSI report configuration at least including transmit power restriction information of beams associated with a CSI report is received by the first apparatus 110 from a second apparatus 120. The first apparatus 110 re-allocates respective transmit power of a plurality of selected beams by restricting respective reference transmit powers of a group of beams from the plurality of selected beams based on the transmit power restriction information and increasing respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams and transmits the CSI report to the second apparatus based on the re-allocation.

[0066] Example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0067] Reference is now made to FIG. 3, which shows a signaling chart 300 for communication according to some example embodiments of the present disclosure. As shown in FIG. 3, the signaling chart 300 involves a first apparatus 110 and a second apparatus 120. For the purpose of discussion, reference is made to FIG. 1 to describe the signaling chart 300.

[0068] As shown in FIG. 3, the first apparatus 110 may report (302) its capability to the second apparatus 120. In this case, the first apparatus 110 may report capability information indicating that the power boosting on SD basis is supported by the first apparatus 110.

[0069] Upon receiving the capability information, the second apparatus 120 may configure transmit power restriction information on beams associated with a PMI codebook. For example, the transmit power restriction information may indicate an allowed, e.g., maximum, transmit power on one or more specific beams.

[0070] It is also possible that the second apparatus 120 may configure a power boosting configuration to indicate how to perform a power boosting operation by the first apparatus 110, e.g., indicating an available transmit power for a downlink data transmission, such as PDSCH transmission, which may be considered as a PDSCH transmission transmit power budget. As an example, the power boosting configuration may also indicate an order of beams associated with the power boosting operation, e.g., by indicating the beam indices or a specific power boosting pattern for beams.

[0071] Then the second apparatus 120 may transmit (304) the CSI report configuration to the first apparatus 110, along with the transmit power restriction information and optionally the power boosting configuration.

[0072] Upon receiving the CSI report configuration, the first apparatus 110 may reallocate (306) respective transmit power of a plurality of selected beams at least based on the transmit power restriction information.

[0073] For example, the first apparatus 110 may restrict respective reference transmit powers of a group of beams from the plurality of selected beams by using the transmit power restriction information, e.g., the maximum transmit power. Based on transmit power reduction amount associated with the group of beams whose reference transmit powers have been reduced or restricted, the first apparatus 110 may further increase respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams.

[0074] More details of the principle for the transmit power reallocation performed by the first apparatus 110 will be further described as below:

[0075] As an example of the number of beams selected by the first apparatus 110 in a CSI report, the first apparatus 110 configured with Rel19 Type-I CSI reporting with up to 128 ports may select and report a set of beams (SD basis vectors, or SD bases) from an oversampled codebook of size N1O1x N2O2.

[0076] Say / z the number of unique selected beams, which depends on the reported rank and the configured codebook mode. For ModeA, and v = 2, one or two different beams can be selected, i.e. ceil ) < < v , whereas for 2 < v < 8 , = cei v / 2) . For ModeB and 2 < v < 4 ,ceil j < f < v, whereas for 5 < v < 8, = ceil( / 2).

[0077] Let Bbe the indices of the selected beams. Say r£the number of layers mapped to beam ij, with j =Note that a beam can be mapped to either one or two layers, i.e., r£e {1,2} and that ^=1n. = v . It is assumed that the second apparatus 120 may configure scaling factors for all the beams in the oversampled codebook and s£< 1 with j = 1, ..., / / , (in linear scale) are the scaling factors of the selected beams. In this case, the plurality of selected beams mentioned above may also be referred to as set B beams, e.g., B = {i1(i2, ... , i }.

[0078] The configured scaling factors may configure a maximum transmit power for a beam, i.e., a maximum portion of the total configured transmit power for the PDSCH signals. This maximum transmit power per beam may also be configured per group of beams or across the selected beams of a group of beams. It is assumed that, as an example, that the reference transmit power per beam, i.e., the assumed transmit power per beam if no power restriction or boosting occurs, corresponds to the portion of the total transmit power per beam obtained by equally distributing the power across all v layers, as is assumed in CSI calculation for NR systems. In a different example, the power allocation strategy may be different than equal power allocation, for example, it could target equal SI NR across layers or maximum throughput (water-filling power allocation).

[0079] The fraction of PDSCH power allocated to a beam ij, without considering any transmit power restriction is rt / v, which may be referred as a reference transmit power of a beam and may correspond to a power scaling factor per layer mapped to that beam of 1 (note that each layer is already normalised to power 1 / u).

[0080] If the beam is power restricted, then the maximum fraction of transmit power for that beam cannot exceed s? (or Si / ri}per layer of that beam), which corresponds to a power scaling factor per layer of s . - v / Ti..

[0081] Therefore, to fulfil the max transmit power per beam, the first apparatus 110 may performs a power-down operation (i.e., a transmit power restriction operation) of a group of beams from the plurality of selected beams by restricting the fraction of transmit power per beam to be min , sf j, where represents a reference transmit power of each beam in a group of beams and sf represent the maximum transmit power. The group of beams on which the reference transmit power has been restricted may be defined as a set of powered-down beams, D = e B | sf < i.e.,the group of beams whose fraction of transmit power needs to be restricted to sf , which causes reduction in total transmit power.

[0082] After the power-down operation, the first apparatus 110 may determine an amount of transmitpower available for power boosting, i.e., an amount of reduced transmit power to be compensated by power boosting. For example, the fraction of transmit power available for power boosting of any other beam that have not been powered down is given by the sum across the beams of set D of the fraction of transmit power that is removed. This fraction of transmit power may represent the total power back-off factor, i.e., a transmit power reduction amount, needed to fulfil the configured power restrictions and is given by: <50-si )> in linear scale, with 0 < <50< 1.

[0083] If 6Q> 0, the first apparatus 110 may perform a power-up operation (i.e., a transmit power increasing operation) of one or more beams that have not been powered-down. For example, the one or more beams to be powered-up may belong to the plurality of selected beams (e.g., set B beams) but other than the group of beams have been powered-down (e.g., set D beams). In this case, the one or more beams may be defined as U = B \ D = {k e B | k £ D , e.g., Set U beams.

[0084] The first apparatus 110 may increase, during the power-up operation, the transmit power of the one or more beams based on a certain order. For example, the first apparatus 110 may obtain a certain fixed or indicated order of the one or more beams, e.g., from the CSI report configuration. It is also possible that the order may be pre-configured or indicated by the second apparatus 120 via other possible signalling. Optionally, the order may also be determined by the first apparatus 110 itself, e.g., based on some related measurements performed by the first apparatus 110.

[0085] That is, the first apparatus 110 may determine the one or more beams to be powered up based on the fixed order of the plurality of selected beams, an order of beams to be reported, an order of increasing beam index or an order of beams indicated by the second apparatus 120.

[0086] During the power-up operation, for example, the first apparatus 110 may select, based on the order of beams, a first beam that has not been powered-up and increase the reference transmit power of the first beam without exceeding the maximum transmit power.

[0087] After that, if the first apparatus 110 determines that a transmit power increase for the first beam satisfies the transmit power reduction amount and a total transmit power of the plurality of selected beams does not exceed an available transmit power associated with downlink data transmission (e.g., the PDSCH transmission transmit power budget), the first apparatus 110 may determine that the power-up operation is completed.

[0088] If the first apparatus 110 determines that the transmit power increase for the first beam is smaller than the transmit power reduction amount, the first apparatus 110 may select, based on the order of beams, a second beam that has not been powered-up and increase the reference transmit power of the second beam without exceeding the maximum transmit power. After that, if a sum of the transmit power increase for the first beam and the transmit power increase for the second beam satisfies the transmit power reduction amount and the total transmit power of the plurality of selected beams does not exceed the available transmit power, the first apparatus 110 may determine that thepower-up operation is completed. If the transmit power reduction amount is still not satisfied, the first apparatus 110 may continue performing the power-up operation on one or more further beams that have not been powered down.

[0089] That is, following a certain fixed or indicated order of the beams in set U = {k^... }, the first apparatus 110 may boost the fraction of transmit power allocated to beam k fromto+ 60, if the new fraction does not exceed the limit s^, or to s^, otherwise, i.e. , the fraction of transmit power allocated to beam k after boosting is + <50. The residual back-offfactor after boosting the first beam is given by < <50, which is smaller thanthe initial back-off factor. If the residual back-off factor is positive, i.e., if> 0, then the first apparatus 110 may proceed by boosting the second beam in set U, k2, by an additional fraction of transmit power that is the minimum betweenand the power headroom available for beam k2, that the fraction of transmit power allocated to beam k2after boosting is 'ngeneral, for beam kj e U, the fraction of transmit power allocated afterboosting is given by Thealgorithm stops after boosting beam kj if <5j < 0 or when all beams in set U have been boosted.

[0090] In conclusion, the first apparatus 110 may perform a power-down operation by applying a per-layer power scaling factor of min to the layers mapped to the selected beam i e B,where B is the set of selected beams. It then identifies the candidate beams for boosting, given by the set u = B \ D = { / , ... , kj, ... } where D = e B | s < is the set of beams that werepowered down. The first apparatus 110 may then may perform a power-up operation to the beams of set U , following a fixed or reported order, by applying a per-layer power boosting factor of the layers mapped to beams is the initial back-off factor andisthe residual back-offfactor after boosting beams k , k2, ... , kj of set U.

[0091] After the transmit power reallocation is completed, the first apparatus 110 may transmit (308) a CSI report to the second apparatus by using the plurality of selected beams with respective reallocated transmit power.

[0092] Based on the CSI report, the second apparatus 120 may perform (310) a PMI reconstruction and a precoder calculation and perform (312) a PDSCH transmission to the first apparatus 110.

[0093] As an option, the first apparatus 110 may indicate, to the second apparatus 120, an order ofbeams for performing the power-up operation and / or respective transmit power increases of these beams. For example, the first apparatus 110 may indicate the order of beams with respective transmit power increases in the CSI report. More details will be described with reference to FIG. 4.

[0094] Reference is now made to FIG. 4, which shows a signaling chart 400 for communication according to some example embodiments of the present disclosure. As shown in FIG. 4, the signaling chart 400 involves a first apparatus 110 and a second apparatus 120. For the purpose of discussion, reference is made to FIG. 1 to describe the signaling chart 400.

[0095] As shown in FIG. 4, the second apparatus 120 may transmit (402), to the first apparatus 110, transmit power restriction information, e.g., via a CSI report configuration. It is also possible that the transmit power restriction information may be indicated by the second apparatus 120 to the first apparatus 110 via other proper signaling.

[0096] Then the first apparatus 110 may perform (404) a transmit power reallocation for a plurality of selected beams. The process and principle for transmit power reallocation has been described with reference to the action 306 in the FIG. 3, which will be omitted here.

[0097] After the transmit power reallocation is completed, the first apparatus 110 may transmit (308) a CSI report to the second apparatus by using the plurality of selected beams with respective reallocated transmit power.

[0098] In this CSI report, the first apparatus 110 may indicate, to the second apparatus 120, an order of beams for performing the power-up operation. For example, if the order of beams for performing the power-up operation is not fixed or pre-configured, or if the first apparatus 110 determines the order by itself, the second apparatus 120 may be aware of the order by the indication of the order of beams in the CSI report. For example, the order of beams may be indicated by corresponding beam indices of theses beams.

[0099] As an example, the CSI report may also indicate respective transmit power increases of the beams which have been powered-up. As another example, the CSI report may also indicate a total power reduction after performing the power down operation.

[0100] Upon receiving the CSI report, the second apparatus 120 may perform (408) a PMI reconstruction and a precoder calculation and perform (410) a PDSCH transmission to the first apparatus 110.

[0101] FIGS. 5A and 5B illustrate examples of a CSI report configuration without and with transmit power restriction on beamforming according to some example embodiments of the present disclosure.

[0102] As shown in FIG. 5A, without the transmit power restriction, the first apparatus 110 may transmit CSI report by using the beams 501 , 502 and 503 with equally transmit power.

[0103] As shown in FIG. 5A, a set of beams 504, 505 and 506 (corresponding to SD basis vectors, or SD bases 507, 508 and 509 respectively) from an oversampled codebook 510 of sizeN-LO-L x N2O2. With the transmit power reallocation proposed in the present disclosure, the beam 504 corresponding to the SD basis 507 and mapped to layers 1 and 2 may be powered down, and the beam 505 corresponding to the SD basis 508 and mapped to layers 3 and 4. The beam 506 corresponding to the SD basis 509 and mapped to layer 5 may be powered up. Then the first apparatus 110 may transmit CSI report by using the beams on which the transmit power reallocation has been performed.

[0104] As described above, the solution proposed in the present disclosure is to configure a UE to reallocate the difference between the configured PDSCH power and the PDSCH power resulting from the selection of one or more powered-downed beam, to one or more of the other selected beams, which are then powered-up. Note that, this beam power boosting is possible only for ranks > 1 , for PMIs with two or more selected beams, and with configured beam scaling factors that allow certain beams to the powered-up. A specified fixed rule may determine the power allocation across the layers mapped to boosted beams. Alternatively, a UE may be configured to report an indication of the power boosting allocation as part of the CSI report.

[0105] In this way, the PDSCH transmit power may satisfy a level configured by the PDSCH-to-CSI- RS EPRE and therefore the performance degradation can be avoided.

[0106] FIG. 6 shows a flowchart of an example method 600 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0107] At block 610, the first apparatus receives, from a second apparatus, a channel state information, CSI, report configuration at least including transmit power restriction information of beams associated with a CSI report.

[0108] At block 620, the first apparatus re-allocates respective transmit power of a plurality of selected beams by restricting respective reference transmit powers of a group of beams from the plurality of selected beams based on the transmit power restriction information and increasing respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams.

[0109] At block 630, the first apparatus transmits the CSI report to the second apparatus based on the re-allocation.

[0110] In some example embodiments, the plurality of selected beams is associated with a precoder matrix indicator, PMI, and wherein one or more layers of the PMI are associated to each selected beam.

[0111] In some example embodiments, the method 600 further comprises: obtaining a maximum transmit power from the transmit power restriction information, and in accordance with a determination that at least one beam in the plurality of selected beams has a reference transmit power greater thanthe maximum transmit power, determining the at least one beam as the group of beams that are to be powered down; and reducing the respective reference transmit powers of the group of beams to the maximum transmit power.

[0112] In some example embodiments, the method 600 further comprises: determining a transmit power reduction amount based on a sum of respective transmit power reductions of the group of beams; increasing a reference transmit power of a beam from remaining beams in the plurality of selected beams other than the group of beams without exceeding a maximum transmit power; and in accordance with a determination that a transmit power increase for the beam satisfies the transmit power reduction amount and a total transmit power of the plurality of selected beams does not exceed an available transmit power associated with the downlink data transmission, determining that the reallocation is completed.

[0113] In some example embodiments, the method 600 further comprises: in accordance with a determination that the transmit power increase for the beam is smaller than the transmit power reduction amount, increasing a reference transmit power of a further beam from remaining beams in the plurality of selected beams other than the group of beams without exceeding the maximum transmit power; and in accordance with a determination that the transmit power increase for the beam and the transmit power increase for the further beam satisfies the transmit power reduction amount and the total transmit power of the plurality of selected beams does not exceed the available transmit power, determining that the reallocation is completed.

[0114] In some example embodiments, the method 600 further comprises: obtaining the available transmit power associated with a downlink data transmission from the CSI report configuration.

[0115] In some example embodiments, the method 600 further comprises: determining, from remaining beams in the plurality of selected beams other than the group of beams, one or more beams to be powered up based on at least one of the following: a fixed order of the plurality of selected beams, an order of beams to be reported, an order of increasing beam index, an order of beams indicated by the second apparatus.

[0116] In some example embodiments, the reference transmit power per beam corresponds to an equal power allocation of a total transmit power budget across the plurality of selected beams.

[0117] In some example embodiments, the method 600 further comprises: transmitting, to the second apparatus in the CSI report, an indication of at least one of the following: a transmit power reduction amount, or an order of the one or more beams with respective transmit power increases.

[0118] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network device.

[0119] FIG. 7 shows a flowchart of an example method 700 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion,the method 700 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0120] At block 710, the second apparatus transmits, to a first apparatus, a channel state information, CSI, configuration at least including transmit power restriction information of beams associated with a CSI report.

[0121] At block 720, the second apparatus receives the CSI report from the first apparatus.

[0122] At block 730, the second apparatus performs a downlink data transmission at least based on the CSI report.

[0123] In some example embodiments, the method 700 further comprises: transmitting, to the first apparatus, an available transmit power associated with the downlink data transmission in the CSI report configuration.

[0124] In some example embodiments, the method 700 further comprises: receiving, from the first apparatus in the CSI report, an indication of at least one of the following: a transmit power reduction amount, or an order of the one or more beams with respective transmit power increases.

[0125] In some example embodiments, the method 700 further comprises: performing a PMI reconstruction and a precoder calculation based on the CSI report; and performing the downlink data transmission by using the reconstructed PMI and calculated precoder.

[0126] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network device.

[0127] FIG. 8 shows a flowchart of an example method 800 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 800 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0128] At block 810, the first apparatus 110 reduces, based on a transmit power restriction, respective reference transmit powers of a group of beams from a plurality of selected beams.

[0129] At block 820, the first apparatus 110 increases respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams.

[0130] At block 830, the first apparatus 110 transmits, to the second apparatus, a CSI report at least indicating an order of the one or more beams with respective transmit power increases.

[0131] In some example embodiments, the plurality of selected beams is associated with a precoder matrix indicator, PMI, and wherein one or more layers of the PMI are associated to each selected beam.

[0132] In some example embodiments, the method 800 further comprises: determining a maximum transmit power based on the transmit power restriction, and in accordance with a determination that at least one beam in the plurality of selected beams has a reference transmit power greater than the maximum transmit power, determining the at least one beam as the group of beams that are to be powered down; and reducing the respective reference transmit powers of the group of beams to themaximum transmit power.

[0133] In some example embodiments, the method 800 further comprises: determining a transmit power reduction amount based on a sum of respective transmit power reductions of the group of beams; increasing a reference transmit power of a beam from remaining beams in the plurality of selected beams other than the group of beams without exceeding a maximum transmit power; and in accordance with a determination that a transmit power increase for the beam satisfies the transmit power reduction amount and a total transmit power of the plurality of selected beams does not exceed an available transmit power associated with the downlink data transmission, determining that the reallocation is completed.

[0134] In some example embodiments, the method 800 further comprises: in accordance with a determination that the transmit power increase for the beam is smaller than the transmit power reduction amount, increasing a reference transmit power of a further beam from remaining beams in the plurality of selected beams other than the group of beams without exceeding the maximum transmit power; and in accordance with a determination that the transmit power increase for the beam and the transmit power increase for the further beam satisfies the transmit power reduction amount and the total transmit power of the plurality of selected beams does not exceed the available transmit power, determining that the reallocation is completed.

[0135] In some example embodiments, the method 800 further comprises: receiving a CSI report configuration from the second apparatus; and obtaining, from the CSI report configuration, at least one of the following: thing available transmit power associated with a downlink data transmission, or thing transmit power restriction associated with the CSI report.

[0136] In some example embodiments, the method 800 further comprises: determining, from remaining beams in the plurality of selected beams other than the group of beams, one or more beams to be powered up based on at least one of the following: a fixed order of the plurality of selected beams, an order of beams to be reported, an order of increasing beam index, an order of beams indicated by the second apparatus.

[0137] In some example embodiments, the reference transmit power per beam corresponds to an equal power allocation of a total transmit power budget across the plurality of selected beams.

[0138] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network device.

[0139] FIG. 9 shows a flowchart of an example method 900 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 900 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0140] At block 910, the second apparatus 120 receives, from a first apparatus, a CSI report at least indicating an order of one or more beams with respective transmit power increases, wherein the oneor more beams are from remaining beams in a plurality of selected beams other than a group of beams on which respective reference transmit powers are restricted.

[0141] At block 920, the second apparatus 120 performs a downlink data transmission at least based on the CSI report.

[0142] In some example embodiments, the method 900 further comprises: transmitting, to the first apparatus, a CSI report configuration at least one of the following: thing available transmit power associated with a downlink data transmission, or thing transmit power restriction associated with the CSI report.

[0143] In some example embodiments, the method 900 further comprises: performing a PMI reconstruction and a precoder calculation based on the CSI report; and performing the downlink data transmission by using the reconstructed PMI and calculated precoder.

[0144] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network device.

[0145] In some example embodiments, a first apparatus capable of performing any of the method 600 (for example, the first apparatus 110 in FIG. 1 ) may comprise means for performing the respective operations of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1 .

[0146] In some example embodiments, the first apparatus comprises means for receiving, from a second apparatus, a channel state information, CSI, report configuration at least including transmit power restriction information of beams associated with a CSI report; means for re-allocating respective transmit power of a plurality of selected beams by restricting respective reference transmit powers of a group of beams from the plurality of selected beams based on the transmit power restriction information and increasing respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams; and means for transmitting the CSI report to the second apparatus based on the re-allocation.

[0147] In some example embodiments, the plurality of selected beams is associated with a precoder matrix indicator, PMI, and wherein one or more layers of the PMI are associated to each selected beam.

[0148] In some example embodiments, the first apparatus further comprises: means for obtaining a maximum transmit power from the transmit power restriction information, and means for in accordance with a determination that at least one beam in the plurality of selected beams has a reference transmit power greater than the maximum transmit power, determining the at least one beam as the group of beams that are to be powered down; and means for reducing the respective reference transmit powers of the group of beams to the maximum transmit power.

[0149] In some example embodiments, the first apparatus further comprises: means for determining a transmit power reduction amount based on a sum of respective transmit power reductions of the group of beams; means for increasing a reference transmit power of a beam from remaining beams in the plurality of selected beams other than the group of beams without exceeding a maximum transmit power; and means for in accordance with a determination that a transmit power increase for the beam satisfies the transmit power reduction amount and a total transmit power of the plurality of selected beams does not exceed an available transmit power associated with the downlink data transmission, determining that the reallocation is completed.

[0150] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the transmit power increase for the beam is smaller than the transmit power reduction amount, increasing a reference transmit power of a further beam from remaining beams in the plurality of selected beams other than the group of beams without exceeding the maximum transmit power; and means for in accordance with a determination that the transmit power increase for the beam and the transmit power increase for the further beam satisfies the transmit power reduction amount and the total transmit power of the plurality of selected beams does not exceed the available transmit power, determining that the reallocation is completed.

[0151] In some example embodiments, the first apparatus further comprises: means for obtaining the available transmit power associated with a downlink data transmission from the CSI report configuration.

[0152] In some example embodiments, the first apparatus further comprises: means for determining, from remaining beams in the plurality of selected beams other than the group of beams, one or more beams to be powered up based on at least one of the following: a fixed order of the plurality of selected beams, an order of beams to be reported, an order of increasing beam index, an order of beams indicated by the second apparatus.

[0153] In some example embodiments, the reference transmit power per beam corresponds to an equal power allocation of a total transmit power budget across the plurality of selected beams.

[0154] I n some example embodiments, the first apparatus further comprises: means for transmitting, to the second apparatus in the CSI report, an indication of at least one of the following: a transmit power reduction amount, or an order of the one or more beams with respective transmit power increases.

[0155] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network device.

[0156] In some example embodiments, a second apparatus capable of performing any of the method 700 (for example, the second apparatus 120 in FIG. 1 ) may comprise means for performing the respective operations of the method 700. The means may be implemented in any suitable form. Forexample, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0157] In some example embodiments, the second apparatus comprises means for transmitting, to a first apparatus, a channel state information, CSI, configuration at least including transmit power restriction information of beams associated with a CSI report; means for receiving the CSI report from the first apparatus; and means for performing a downlink data transmission at least based on the CSI report.

[0158] In some example embodiments, the second apparatus further comprises: means for transmitting, to the first apparatus, an available transmit power associated with the downlink data transmission in the CSI report configuration.

[0159] I n some example embodiments, the second apparatus further comprises: means for receiving, from the first apparatus in the CSI report, an indication of at least one of the following: a transmit power reduction amount, or an order of the one or more beams with respective transmit power increases.

[0160] In some example embodiments, the second apparatus further comprises: means for performing a PMI reconstruction and a precoder calculation based on the CSI report; and means for performing the downlink data transmission by using the reconstructed PMI and calculated precoder.

[0161] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network device.

[0162] In some example embodiments, a first apparatus capable of performing any of the method 800 (for example, the first apparatus 110 in FIG. 1 ) may comprise means for performing the respective operations 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. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1 .

[0163] In some example embodiments, the first apparatus comprises means for reducing, based on a transmit power restriction, respective reference transmit powers of a group of beams from a plurality of selected beams; means for increasing respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams; and means for transmitting, to the second apparatus, a CSI report at least indicating an order of the one or more beams with respective transmit power increases.

[0164] In some example embodiments, the plurality of selected beams is associated with a precoder matrix indicator, PMI, and wherein one or more layers of the PMI are associated to each selected beam.

[0165] In some example embodiments, the first apparatus further comprises: means for determining a maximum transmit power based on the transmit power restriction, and means for in accordance witha determination that at least one beam in the plurality of selected beams has a reference transmit power greater than the maximum transmit power, determining the at least one beam as the group of beams that are to be powered down; and means for reducing the respective reference transmit powers of the group of beams to the maximum transmit power.

[0166] In some example embodiments, the first apparatus further comprises: means for determining a transmit power reduction amount based on a sum of respective transmit power reductions of the group of beams; means for increasing a reference transmit power of a beam from remaining beams in the plurality of selected beams other than the group of beams without exceeding a maximum transmit power; and means for in accordance with a determination that a transmit power increase for the beam satisfies the transmit power reduction amount and a total transmit power of the plurality of selected beams does not exceed an available transmit power associated with the downlink data transmission, determining that the reallocation is completed.

[0167] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the transmit power increase for the beam is smaller than the transmit power reduction amount, increasing a reference transmit power of a further beam from remaining beams in the plurality of selected beams other than the group of beams without exceeding the maximum transmit power; and means for in accordance with a determination that the transmit power increase for the beam and the transmit power increase for the further beam satisfies the transmit power reduction amount and the total transmit power of the plurality of selected beams does not exceed the available transmit power, determining that the reallocation is completed.

[0168] In some example embodiments, the first apparatus further comprises: means for receiving a CSI report configuration from the second apparatus; and means for obtaining, from the CSI report configuration, at least one of the following: an available transmit power associated with a downlink data transmission, or a transmit power restriction associated with the CSI report.

[0169] In some example embodiments, the first apparatus further comprises: means for determining, from remaining beams in the plurality of selected beams other than the group of beams, one or more beams to be powered up based on at least one of the following: a fixed order of the plurality of selected beams, an order of beams to be reported, an order of increasing beam index, an order of beams indicated by the second apparatus.

[0170] In some example embodiments, the reference transmit power per beam corresponds to an equal power allocation of a total transmit power budget across the plurality of selected beams.

[0171] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network device.

[0172] In some example embodiments, a second apparatus capable of performing any of the method 900 (for example, the second apparatus 120 in FIG. 1 ) may comprise means for performing therespective operations 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. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0173] In some example embodiments, the second apparatus comprises means for receiving, from a first apparatus, a CSI report at least indicating an order of one or more beams with respective transmit power increases, wherein the one or more beams are from remaining beams in a plurality of selected beams other than a group of beams on which respective reference transmit powers are restricted; and means for performing a downlink data transmission at least based on the CSI report.

[0174] In some example embodiments, the second apparatus further comprises: means for transmitting, to the first apparatus, a CSI report configuration at least one of the following: an available transmit power associated with a downlink data transmission, or means for a transmit power restriction associated with the CSI report.

[0175] In some example embodiments, the second apparatus further comprises: means for performing a PMI reconstruction and a precoder calculation based on the CSI report; and means for performing the downlink data transmission by using the reconstructed PMI and calculated precoder.

[0176] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network device.

[0177] FIG. 10 is a simplified block diagram of a device 1000 that is suitable for implementing example embodiments of the present disclosure. The device 1000 may be provided to implement a communication device, for example, the first apparatus 110 or the second apparatus 120 as shown in FIG. 1. As shown, the device 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.

[0178] The communication module 1040 is for bidirectional communications. The communication module 1040 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interfaces may represent any interface that is necessary for communication with other network elements. In some example embodiments, the communication module 1040 may include at least one antenna.

[0179] The processor 1010 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 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.

[0180] 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), an optical disk, a laser disk, and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random-access memory (RAM) 1022 and other volatile memories that will not last in the power-down duration.

[0181] A computer program 1030 includes computer executable instructions that are executed by the associated processor 1010. The instructions of the program 1030 may include instructions for performing operations / acts of some example embodiments of the present disclosure. The program 1030 may be stored in the memory, e.g., the ROM 1024. The processor 1010 may perform any suitable actions and processing by loading the program 1030 into the RAM 1022.

[0182] The example embodiments of the present disclosure may be implemented by means of the program 1030 so that the device 1000 may perform any process of the disclosure as discussed with reference to FIG. 2 to FIG.9. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0183] In some example embodiments, the program 1030 may be tangibly contained in a computer readable medium 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. In some example embodiments, the computer readable medium may include any types of non-transitory storage medium, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e. , tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0184] FIG. 11 shows an example of the computer readable medium 1100 which may be in form of CD, DVD or other optical storage disk. The computer readable medium 1100 has the program 1030 stored thereon.

[0185] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, and other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. Although various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0186] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer readable medium, such as a non-transitory computer readable medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target physical or virtual processor, to carry out any of the methods as described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machineexecutable 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.

[0187] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general-purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0188] In the context of the present disclosure, the computer program code or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0189] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random-access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0190] Further, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, although several specificimplementation 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. Unless explicitly stated, certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated, various features that are described in the context of a single embodiment may also be implemented in a plurality of embodiments separately or in any suitable subcombination.

[0191] Although the present disclosure has been described in languages specific to structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

WHAT IS CLAIMED IS:1 . A first apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: reduce, based on a transmit power restriction, respective reference transmit powers of a group of beams from a plurality of selected beams; increase respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams; and transmit, to the second apparatus, a CSI report at least indicating an order of the one or more beams with respective transmit power increases.

2. The first apparatus of claim 1 , wherein the plurality of selected beams is associated with a precoder matrix indicator, PMI, and wherein one or more layers of the PMI are associated to each selected beam.

3. The first apparatus of claim 1 or 2, wherein the first apparatus is caused to: determine a maximum transmit power based on the transmit power restriction, and in accordance with a determination that at least one beam in the plurality of selected beams has a reference transmit power greater than the maximum transmit power, determine the at least one beam as the group of beams that are to be powered down; and reduce the respective reference transmit powers of the group of beams to the maximum transmit power.

4. The first apparatus of any of claims 1-3, wherein the first apparatus is caused to: determine a transmit power reduction amount based on a sum of respective transmit power reductions of the group of beams; increase a reference transmit power of a beam from remaining beams in the plurality of selected beams other than the group of beams without exceeding a maximum transmit power; and in accordance with a determination that an transmit power increase for the beam satisfies the transmit power reduction amount and a total transmit power of the plurality of selected beams does not exceed an available transmit power associated with the downlink data transmission, determine that the reallocation is completed.

5. The first apparatus of claim 4, wherein the first apparatus is caused to: in accordance with a determination that the transmit power increase for the beam is smaller than the transmit power reduction amount, increase a reference transmit power of a further beam from remaining beams in the plurality of selected beams other than the group of beams without exceeding the maximum transmit power; and in accordance with a determination that the transmit power increase for the beam and the transmit power increase for the further beam satisfies the transmit power reduction amount and the total transmit power of the plurality of selected beams does not exceed the available transmit power, determine that the reallocation is completed.

6. The first apparatus of claim 4 or 5, wherein the first apparatus is caused to: receive a CSI report configuration from the second apparatus; and obtain, from the CSI report configuration, at least one of the following: the available transmit power associated with a downlink data transmission, or the transmit power restriction associated with the CSI report.

7. The first apparatus of any of claims 1-6, wherein the first apparatus is caused to: determine, from remaining beams in the plurality of selected beams other than the group of beams, one or more beams to be powered up based on at least one of the following: a fixed order of the plurality of selected beams, an order of beams to be reported, an order of increasing beam index, an order of beams indicated by the second apparatus.

8. The first apparatus of any of claims 1-7, wherein the reference transmit power per beam corresponds to an equal power allocation of a total transmit power budget across the plurality of selected beams.

9. The first apparatus of any of claims 1-8, wherein the first apparatus comprises a terminal device and the second apparatus comprises a network device.

10. A second apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to:receive, from a first apparatus, a CSI report at least indicating an order of one or more beams with respective transmit power increases, wherein the one or more beams are from remaining beams in a plurality of selected beams other than a group of beams on which respective reference transmit powers are restricted; and perform a downlink data transmission at least based on the CSI report.11 . The second apparatus of claim 10, wherein the second apparatus is caused to: transmit, to the first apparatus, a CSI configuration at least one of the following: the available transmit power associated with a downlink data transmission, or the transmit power restriction associated with the CSI report.

12. The second apparatus of claim 10 or 11 , wherein the second apparatus is caused to: perform a PMI reconstruction and a precoder calculation based on the CSI report; and perform the downlink data transmission by using the reconstructed PMI and calculated precoder.

13. The second apparatus of any of claims 10-12, wherein the first apparatus comprises a terminal device and the second apparatus comprises a network device.

14. A method comprising: reducing, based on a transmit power restriction, respective reference transmit powers of a group of beams from a plurality of selected beams; increasing respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams; and transmitting, to the second apparatus, a CSI report at least indicating an order of the one or more beams with respective transmit power increases.

15. A method comprising: receiving, from a first apparatus, a CSI report at least indicating an order of one or more beams with respective transmit power increases, wherein the one or more beams are from remaining beams in a plurality of selected beams other than a group of beams on which respective reference transmit powers are restricted; and performing a downlink data transmission at least based on the CSI report.

16. A first apparatus comprising: means for reducing, based on a transmit power restriction, respective reference transmit powers ofa group of beams from a plurality of selected beams; means for increasing respective reference transmit powers of one or more beams from remaining beams in the plurality of selected beams other than the group of beams; and means for transmitting, to the second apparatus, a CSI report at least indicating an order of the one or more beams with respective transmit power increases.

17. A second apparatus comprising: means for receiving, from a first apparatus, a CSI report at least indicating an order of one or more beams with respective transmit power increases, wherein the one or more beams are from remaining beams in a plurality of selected beams other than a group of beams on which respective reference transmit powers are restricted; and means for performing a downlink data transmission at least based on the CSI report.

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

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