RU2818404C1 - Method of frequency-selective control of transmission power, device implementing it and their versions - Google Patents

Abstract

FIELD: wireless communication.

SUBSTANCE: technical result is achieved by the fact that control of transmission power by a user terminal (UE) of an uplink (UL) comprises breaking down a transmission-reception point (TRP) of an available frequency band into a plurality of sub-bands, to be used in frequency-selective control of UL transmission power, determination of transmission power adjustment values for each subband obtained by splitting, and transmitting to the UE the determined split ranges and the corresponding transmission power adjustment values for these sub-ranges for subsequent use thereof.

EFFECT: reduced inter-cell interference and high efficiency of user terminals located close to cell boundaries.

26 cl, 9 dwg, 2 tbl

Description

Technical field

[0001] The present disclosure relates to the field of communications, namely, methods and apparatus for frequency selective transmit power control for sixth generation (6G) communications systems supporting multi-user (MU) mode and spatial signal encoding (MIMO) antenna systems.

State of the art

[0002] The 6G system, which is expected to be deployed as one of the possible options in the upper-mid frequency band (10-12 GHz), will support massive MIMO phased array antennas (≥1024 antenna elements) with hybrid analog and digital transmit-receive point (TRP) beamforming with a large number of digital antenna ports (≥128). Multi-user (MU) MIMO mode on both downlink (DL) and uplink (UL), which allows user terminals (UEs) to simultaneously receive and/or transmit signals on the same frequencies, is considered a very attractive technology for 6G system with extreme MIMO (xMIMO) to unlock the full potential of sixth generation communications.

[0003] Orthogonal frequency division multiple access (OFDMA) is being considered as one of the possible access schemes for multiple UEs in a 6G system. OFDMA is characterized by frequency-selective scheduling of time-frequency resources for data transmission/reception. However, the use of MU-MIMO with frequency selective scheduling in OFDMA usually results in a different number of UEs simultaneously transmitting/receiving the data signal in the available frequency band per unit time.

Problems/tasks solved by the invention

[0004] UL transmit power control determines the power of UL transmitted signals/channels, such as the Physical Uplink Shared Channel (PUSCH), to reduce mutual interference and power consumption of the UE. Traditional transmit power control (TPC) in UL in the fifth generation (5G) 'new radio' (NR) communication system includes two components (members): an autonomous component and a feedback-based component. The open-loop term is determined autonomously by the user terminal based on DL measurements. The closed-loop term is determined by the downlink control information (DCI) sent from the TRP to the UE.

[0005] In a 6G system, the use of xMIMO will enable MU-MIMO with a much larger number of user terminals that can simultaneously transmit UL on the same resource blocks (RBs) than in traditional 5G NR communications systems with massive MIMO. Thus, the significantly higher overall transmit power level in MU-MIMO may result in increased inter-cell interference (ICI), which will be spatially isotropic due to multiple randomly distributed UE sources. Increasing ICI in MU-MIMO may, in turn, result in decreased UE performance at the cell edge in UL.

[0006] In addition, the use of a traditional (i.e., non-frequency selective) UL power control scheme for MU-MIMO, which uses a single overall transmit power trim value, may result in interference that is more frequency selective from - due to (1) different numbers of UEs carrying out simultaneous UL transmissions on the same frequency resources and (2) different decisions taken to pair simultaneous UL transmissions of different UEs on the same frequencies. In other words, the total power spectral density (PSD) of such transmissions becomes uneven in frequency in this case.

[0007] The technical solution described in US patent US9661592B2, published on May 23, 2017 and entitled 'UPLINK POWER CONTROL METHOD AND APPARATUS IN A BEAM-FORMING BASED WIRELESS COMMUNICATION SYSTEM' (' DEVICE AND METHOD FOR CONTROL OF POWER OISH LINE COMMUNICATIONS IN A WIRELESS COMMUNICATION SYSTEM BASED ON BEAM FORMING' ). However, the known technical solution lacks adaptation of transmission power control in the frequency domain, so the known technical solution suffers from one or more of the problems described above.

The essence of the invention (means of solving the specified problems/tasks)

[0008] Thanks to the present invention, the above and other problems, although not explicitly stated, but related to or resulting from the above problems in the prior art, are solved or at least mitigated. The above and additional problems/objectives and the corresponding beneficial technical effects achieved will be further discussed in the following description in the context of specific features of the technical solution proposed in this application.

[0009] In a first aspect of the present invention, there is provided a transceiver point (TRP) method for frequency selective control of transmit power by a user terminal (UE) of an uplink (UL) channel, the method including: dividing an available frequency a range into a plurality of sub-bands to be used by the user terminal when transmitting a UL channel on a TRP with frequency selective transmit power control; setting, for each subband of the plurality of subbands, a transmission power adjustment value to be applied by the user terminal to adjust the power in the corresponding subband when transmitting the UL channel to the TRP; transmitting to the UE an indication of said plurality of subbands, and for each subband the indication additionally signals a transmit power adjustment value corresponding to this subband; and wait to receive or receive from the UE a transmission of a UL channel with frequency selective power adjustment performed based on the transmitted indication.

[0010] In a possible implementation of the method according to the first aspect of the present invention, said indication is a transmit power control (TPC) command in a downlink control information (DCI) message or in a radio resource control (RRC) procedure configuration message.

[0011] In a possible implementation of the method according to the first aspect of the present invention, the UL channel is a physical uplink shared channel (PUSCH).

[0012] In a possible implementation of the method according to the first aspect of the present invention, partitioning the available frequency band into a plurality of sub-bands and setting the corresponding transmission power adjustment values is accomplished by performing an RRC procedure between the TRP and the UE.

[0013] In a possible implementation of the method according to the first aspect of the present invention, the available frequency range is partitioned into a plurality of equal-width sub-bands or into a plurality of different-width sub-bands, the width of the sub-bands being specified by the number of resource elements (RE) or the number of resource blocks (RB) so that such that the subband includes one or more REs or one or more RBs.

[0014] In an exemplary implementation of the method according to the first aspect of the present invention, performing partitioning of an available frequency range into a plurality of subbands includes forming a combined subband by combining two or more adjacent subbands of the same width if the two or more adjacent subbands are set to the same power trim value transmissions, the start and end of the combined subband being indicated by: the index of the first RE or RB of the combined subband and the index of the last RE or RB of the combined subband; or the index of the first RE or RB of the combined subband and the number of RE or RB in the combined subband; or an index of the first RE or RB of the combined subband and an index of the first RE or RB of the subband subsequent to said combined subband.

[0015] In an exemplary implementation of the method according to the first aspect of the present invention, setting, for a subband of the plurality of subbands, transmission power adjustment values is performed depending on the number of user terminals (UEs) simultaneously transmitting in the given subband.

[0016] In an exemplary implementation of the method according to the first aspect of the present invention, the range of possible power trim values is expanded dynamically by using additional TPC command bit values indicating additional transmit power trim values in the DCI message or RRC configuration message.

[0017] In a possible implementation of the method according to the first aspect of the present invention, the transmit power adjustment value in each subband is set relative to a common reference transmit power level for all subbands or relative to the transmit power level in the previous subband.

[0018] In a possible implementation of the method according to the first aspect of the present invention, the transmit-receiver point (TRP) is a base station (BS), access point (AP), or node B (NodeB).

[0019] In a possible implementation of the method according to the first aspect of the present invention, frequency selective power adjustment based on the transmitted indication modifies the power spectral density (PSD).

[0020] In a second aspect of the present invention, there is provided a transmit-receive point (TRP) comprising a transmit-receive antenna unit and a processor configured to implement the method of the first aspect of the present invention or any possible implementation of the first aspect of the present invention.

[0021] In a third aspect of the present invention, there is provided a storage medium storing processor-executable instructions that, when executed by a processor of a device equipped with a transceiver antenna unit, perform the method of the first aspect of the present invention or any possible implementation of the first aspect of the present invention.

[0022] In a fourth aspect of the present invention, there is provided a user terminal (UE) method for frequency selective control of transmission power of an uplink (UL) channel to a transmit-receiver point (TRP), the method including the steps of: receiving from TRP indicating a plurality of subbands obtained by dividing the available frequency range and to be used by the user terminal when transmitting a UL channel on TRP with frequency selective transmit power control, wherein for each subband the said indication further signals a subband-specific transmit power adjustment value to be used by the user terminal for adjusting the power in this subband when transmitting the UL channel to the TRP; and transmitting the UL channel to the TRP, performing frequency selective power adjustment based on the received indication.

[0023] In a possible implementation of the method according to the fourth aspect of the present invention, said indication is a transmit power control (TPC) command in a downlink control information (DCI) message or in a radio resource control (RRC) procedure configuration message between the TRP and the UE.

[0024] In a possible implementation of the method according to the fourth aspect of the present invention, the UL channel is a physical uplink shared channel (PUSCH).

[0025] In a possible implementation of the method according to the fourth aspect of the present invention, a plurality of sub-bands and a corresponding plurality of transmission power adjustment values are configured by performing an RRC procedure between the TRP and the UE.

[0026] In a possible implementation of the method according to the fourth aspect of the present invention, the plurality of subbands includes equal-width subbands and/or different-width subbands, wherein the width of the subbands is indicated by the number of resource elements (RE) or the number of resource blocks (RB) so that that the subband includes one or more REs or one or more RBs.

[0027] In a possible implementation of the method according to the fourth aspect of the present invention, the plurality of subbands includes a combined subband, the beginning and the end of the combined subband being indicated by: an index of the first RE or RB of the combined subband and an index of the last RE or RB of the combined subband; or the index of the first RE or RB of the combined subband and the number of RE or RB in the combined subband; or an index of the first RE or RB of the combined subband and an index of the first RE or RB of the subband subsequent to said combined subband.

[0028] In a possible implementation of the method according to the fourth aspect of the present invention, for a subband of the plurality of subbands, the transmission power adjustment value indicated in the indication is set depending on the number of other UEs transmitting simultaneously with the UE in the given subband.

[0029] In an exemplary implementation of the method according to the fourth aspect of the present invention, the range of possible power trim values is expanded dynamically by using additional TPC command bit values indicating additional transmit power trim values in the DCI message or RRC configuration message.

[0030] In a possible implementation of the method according to the fourth aspect of the present invention, the transmit power adjustment value in each subband is set relative to a common reference transmit power level for all subbands or relative to the transmit power level in the previous subband.

[0031] In a possible implementation of the method according to the fourth aspect of the present invention, the frequency selective power adjustment performed based on the received indication modifies the power spectral density (PSD).

[0032] In a fifth aspect of the present invention, there is provided a user terminal (UE) comprising a transceiver antenna unit and a processor configured to implement the method of the fourth aspect of the present invention or any possible implementation of the fourth aspect of the present invention.

[0033] In a sixth aspect of the present invention, there is provided a storage medium storing processor-executable instructions that, when executed by a processor of a device equipped with a transceiver antenna unit, perform the method of the fourth aspect of the present invention or any possible implementation of the fourth aspect of the present invention.

[0034] In a seventh aspect of the present invention, there is provided a communication system comprising one or more Transmission Points (TRPs) according to the second aspect of the present invention or any possible implementation of the second aspect of the present invention and one or more user terminals (UE) according to the fifth aspect of the present invention the invention or any possible implementation of the fifth aspect of the present invention.

Brief description of drawings

[FIG. 1] Fig. 1 illustrates a flowchart of a transceiver point (TRP) method for frequency selective control of transmission power by a user terminal (UE) of an uplink (UL) channel according to the first aspect of the present invention.

[FIG. 2] Fig. 2 illustrates a schematic diagram of a Transmission Point (TRP) according to the second aspect of the present invention, which is configured to implement the method according to the first aspect of the present invention.

[FIG. 3] Fig. 3 illustrates a flowchart of a user terminal (UE) method for frequency selective transmit power control of an uplink (UL) channel to a Transmission Point (TRP) according to a fourth aspect of the present invention.

[FIG. 4] Fig. 4 illustrates a schematic diagram of a user terminal (UE) according to the fifth aspect of the present invention, which is configured to implement the method according to the fourth aspect of the present invention.

[FIG. 5] Fig. 5 illustrates a schematic diagram of a communication system according to a seventh aspect of the present invention.

[FIG. 6] Fig. 6 illustrates a visual comparison between traditional MU-MIMO and MU-MIMO with frequency selective transmit power control proposed herein.

[FIG. 7] Fig. 7 illustrates an exemplary scheme for adjusting the transmit power in each subband relative to a common reference transmit power level for all subbands.

[FIG. 8] Fig. 8 illustrates an exemplary scheme for adjusting the transmit power in each subband relative to the transmit power level in the previous subband.

[FIG. 9] Fig. 9 is a cumulative distribution function (CDF) for UE performance in megabits per second (Mbps), illustrating the performance gain of a near-cell edge user terminal (UE) employing frequency selective transmit power control according to the present invention, compared with the performance of a user terminal (UE) not employing such frequency selective transmit power control.

Detailed Description of Embodiments

[0035] FIG. 1 illustrates a flowchart of a transceiver point (TRP) method for frequency selective control of transmission power by a user terminal (UE) of an uplink (UL) channel according to the first aspect of the present invention. The method begins and proceeds to step S100, where the available frequency band is divided into a plurality of frequency sub-bands to be used by the user terminal in frequency selective transmit power control of the UL channel on the TRP. The UL channel may be a physical uplink shared channel (PUSCH), and the available frequency band may be any operating frequency band that is used for communication between the TRP and the UE, including the one currently used for 4G LTE, Pre- 5G, 5G NR, etc. Non-limiting examples of the available frequency range subdivided in step S100 may include Frequency Range 1 (FR1) up to 7.125 GHz or at least a portion thereof, Frequency Range 2 (FR2) from 24.25 GHz to 71 GHz or at least at least part thereof, or the frequency range from 7.125 GHz to 24.25 GHz or at least part thereof.

[0036] The partitioning in step S100 of the entire available frequency range into subbands may be performed in any suitable manner and may occur, for example, when performing an RRC procedure between the TRP and the UE. In an exemplary implementation, the partitioning may be performed along a selectable fixed layout, for example, along the boundaries of one, two, or more RBs or REs. In another possible embodiment, the total number of subbands can be selected, which should be obtained by partitioning the entire frequency range available for partitioning. Thus, the partitioning S100 of the available frequency range can be done by partitioning it into a plurality of equal-width sub-bands or into a plurality of different-width sub-bands. Such partitioning may be done dynamically (or, in other words, adaptively when one partitioned band is wider or narrower than one or more other partitioned bands) according to the frequency resources allocated for UL transmissions by OFDMA's frequency selective resource scheduling applied in conjunction with MU-MIMO.

[0037] As a non-limiting illustration of partitioning, the right side of FIG. 6 schematically shows an example of dividing the available frequency range into frequency sub-bands 1 to 3 for UL transmissions by four user terminals (UE1, UE2, UE3, UE4). Subrange 1 includes five resource blocks (RB) from RB1 to RB5, subrange 2 includes five resource blocks from RB6 to RB10, subrange 3 includes two resource blocks from RB11 to RB12. The boundaries of the resulting subbands (eg, illustrated subbands 1 to 3) may be determined depending on the number of user terminals simulcasting on the subband and/or depending on the power trim setting value of the user terminals simulcasting on the subband.

[0038] As a non-limiting example, the boundary of subband 1 may be determined to be the boundary of RB5 and RB6, since in each RB RB1 to RB5 the number of user terminals transmitting simultaneously is 3, and from RB6 (inclusive) this number changes to 2. In another non-limiting example, the boundary of subband 1 may be determined to be the boundary of RB5 and RB6, since in each RB RB1 to RB5 the transmit power trim value of each UE UE1 to UE4 is the same, and starting from RB6 (inclusive) ) this value changes. In similar ways, boundaries between other adjacent subbands (eg, between subbands 2 and 3 illustrated in FIG. 6 ) obtained by partitioning in step S100 can be determined. Resource blocks are used by way of example only; alternatively, subbands may be defined by the number of smaller portions of the available frequency range (eg, the number of resource elements (RE)) or the number of larger portions of the available frequency range. Thus, a subband may include one or more RBs or one or more REs.

[0039] In another possible implementation, the partitioning of the available frequency range at step S100 can be carried out by initially partitioning the entire available frequency range into a plurality of equal-width sub-bands (for example, along the boundaries of one RB/RE, i.e., one sub-band=one RB/RE; or along the boundaries of two adjacent RB/RE, i.e. one subband = two RB/RE, etc.) with subsequent determination of the corresponding power adjustment value for each such subrange and merging adjacent subranges for which the same power adjustment value is determined, into one subrange. This possible implementation can further reduce the amount of control information signaled to the UE (eg, reduce the total number of TPC commands signaled).

[0040] The beginning and end (i.e., boundaries) of each subband obtained by partitioning in step S100 may be indicated by, but not limited to, the index of the first RE or RB of the subband and the index of the last RE or RB of the subband (in the example shown on the right in Fig. 6 : for subband 1: index RB1 and index RB5); or by the index of the first RE or RB of the subrange and the number of RE or RB in the subrange (in the mentioned example: for subrange 1: by the index RB1 and the number 5 (if RB1 itself is counted/taken into account) or 4 (if RB1 itself is not counted/not taken into account); or the index of the first RE or RB of the subband and the index of the first RE or RB of the next subband (in the example mentioned: for subband 1: index RB1 and index RB6) the subbands obtained as a result of partitioning in step S100 (together with the corresponding power trim values, the definition of which will be detailed). described below) may be signaled to the UE from the TRP by one or more indications. Such indications may be, but are not limited to, a TPC command in a DCI message or in an RRC procedure configuration message.

[0041] After executing step S100, the method proceeds to executing step S105, in which, for each sub-band of the plurality of sub-bands, a transmit power adjustment value δ to be applied by the user terminal to adjust the power in the corresponding sub-band when transmitting the UL channel to the TRP is set. In one non-limiting embodiment of this step, the TRP may select a transmit power trim value δ for a frequency subband depending on the number of UEs transmitting in that frequency band. If N UEs are transmitting simultaneously, then the TRP selects, from the possible preconfigured transmit power trim values available for the TPC command in the DCI message or in the RRC procedure configuration message, the value δ closest to -10*log10(N) dB. So, if two UEs transmit simultaneously, then the transmission power of each should be reduced by 2 times, i.e., δ = -10*log10(2) ≈ -3 dB. In the case of transmission in the subband of a single UE, the transmission power adjustment value δ will be equal to δ =-10*log10(1)=0 dB; in this case, such δ value may not be signaled for the corresponding subband in the UE indication, and the absence of a transmit power adjustment value δ for the subband in the received TRP indication may be interpreted by the user terminal to mean that no transmit power adjustment should be made for that subband. In general, the disclosed technology should not be limited to the above example implementation of this step, since the TRP can select the transmit power adjustment value δ for a frequency subband not only based on the number of users in the MU-MIMO transmission mode for a certain frequency subband, but in any suitable arbitrary manner. For example, the value of δ may be adjusted to reduce power in a certain frequency range where it will not degrade transmission immunity from the UE to the TRP. This will reduce the total power of the UE transmitter, and thereby increase the operating time of a single charge of the UE battery.

[0042] In an exemplary implementation, the transmit power trim value in each subband may be set relative to a common transmit power reference level P ₀ for all subbands, as shown in FIG. 7. Typically, the reference common transmit power level P ₀ for all subbands is the same as the target power spectral density ( PSD ₀ ) value, which is determined for a single user in the subband, ie, single user (SU)-MIMO. Therefore, to set the transmit power adjustment value δ for the frequency subband in this case relative to the overall reference power level P ₀ , this value can, in a non-limiting example, be set as described above, i.e. as δ =-10*log10(N) dB.

[0043] In another possible implementation, the transmit power trim value in each subband may be set relative to the transmit power level in the previous subband, as shown in FIG. 8 . A non-limiting example of setting the transmission power adjustment value δ for the (i+1) -th subband in this case could be: δ= 10*log10(N _i /N _{i +1} ) dB, where N _i is the number of MU-MIMO users in i -th subband, and N _i+1 is the number of MU-MIMO users in the ( i+1 )th subband.

[0044] After executing step S105, the method proceeds to executing step S110, in which an indication of the plurality of sub-bands and the corresponding transmission power adjustment set values δ is transmitted to the UE. The transmission can be carried out over a communication network in which the TRP and the UE are participants. In a possible implementation, said indication is, but is not limited to, a TPC command in a DCI message or in an RRC procedure configuration message. In another possible implementation, the TPC command may be sent to the UE in a different message, for example, in a separate message for the TPC command, i.e. in the TPC command message. In addition, it should be noted that the indication may include sending a plurality of separate TPC commands, each signaling a specific subband and its corresponding transmit power trim value δ , or, alternatively, may include sending a single general TCP command indicating all subbands obtained by partitioning in step S100 and the corresponding transmission power adjustment values δ .

[0045] After executing step S110, the method proceeds to executing step S115, in which the TRP waits to receive or receives from the UE a transmission of the UL channel with frequency selective power adjustment, which is performed by the user terminal based on at least the information contained in the transmitted in step S110 indication. In an alternative embodiment, the method may proceed to a step (not shown in FIG. 1 ) in which the TRP waits for the UE to transmit a frequency selective power adjustment UL channel that is performed by the user terminal based on at least the information contained in the transmitted step S110 indication. Frequency selective power adjustment based on the transmitted indication reduces the overall UL transmit power level in MU-MIMO mode in wireless communication systems with frequency selective resource scheduling OFDMA. In other words, the frequency selective power adjustment carried out based on the transmitted indication is a finer power adjustment that modifies the power spectral density (PSD) to reduce and flatten it across the entire S100 partitioned available frequency range (compare the left side of FIG. 6 with its right side), resulting in a reduction in inter-cell interference (ICI) and an increase (see FIG. 9 ) in the performance of UL transmissions carried out by user terminals located close to the cell edge.

[0046] In this case, reducing the transmission power of the UE in a certain subband is not a problem, because this reduced UE transmit power will still be sufficient to receive data from the UE on the TRP side without error. The sufficiency/inadequacy may, in a non-limiting example, be controlled by the TRP side: for example, a large number of users (exceeding a predefined threshold number of users per subband) may not be placed in the same frequency subband in MU-MIMO mode if such transmission mode would result in such a power drawdown (exceeding a predetermined power drawdown threshold value) of the transmitter of any of the UEs, at which the transmission power of the UE will not be sufficient to accurately receive data signals from that UE.

[0047] In an exemplary implementation, the dynamic range of possible power trim values may be expanded, as needed, by using additional TPC command bit values in the DCI message or RRC configuration message indicating additional transmit power trim values. In a non-limiting example, additional (new) transmit power trim values for the TPC command may be configured for use in signaling the power trim value in a DCI message as follows:

[0048] Table 1: Additional bits for the TPC command

TPC Cumulative power adjustment value, dB Absolute value of power adjustment, dB 000 -1 -4 001 0 -1 010 1 1 011 3 4 New bit values and corresponding configurable power trim values: 100 -3 -7 101 -5 -10 110 5 -13 111 7 -16

[0049] The absence of certain specific power trim values (eg, 2 dB, 6 dB) from Table 1 should not be interpreted to mean that such specific values are not applicable. Instead, this absence is explained only by the limited number of bits encoding power levels, i.e. more additional power levels may be specified by a larger number of corresponding bit values and signaled in the DCI message. Therefore, in an actual implementation, the specific dB values listed in the 'Cumulative dB Power Value' and 'Absolute dB Power Value' columns of Table 1 above should not be interpreted as a limitation, i.e. only possible values, since other specific dB values may be provided depending on the implementation. In addition, the dynamic range of power trim values can be expanded even further by encoding additional TPC commands with more bits, such as four bits, five bits, etc.

[0050] In another non-limiting example, additional (new) transmit power trim values for the TPC command may be dynamically configured and signaled in the RRC procedure configuration message. In this case, the contents of the RRC procedure configuration message fields can be specified as shown in the following Table 2:

[0051] Table 2: RRC Configuration for TPC Command Power Trim Values

TPC Cumulative power adjustment value, dB Absolute value of power adjustment, dB 00 The specific value is configured dynamically by the RRC procedure The specific value is configured dynamically by the RRC procedure 01 The specific value is configured dynamically by the RRC procedure The specific value is configured dynamically by the RRC procedure 10 The specific value is configured dynamically by the RRC procedure The specific value is configured dynamically by the RRC procedure eleven The specific value is configured dynamically by the RRC procedure The specific value is configured dynamically by the RRC procedure

[0052] With this approach, it is possible to change the band width dynamically (as needed) by communicating the corresponding changes to the UE with the appropriate RRC procedure configuration message. Thus, the technical solution proposed in this disclosure is adapted to handle very large changes in the number of planned user terminals, which is particularly attractive for operation and support with xMIMO. In addition, it also helps reduce interference to other cells when using MU-MIMO.

[0053] FIG. 2 illustrates a schematic representation of a transmit-receive point (TRP, 300) according to the second aspect of the present invention, which is configured to implement the method according to the first aspect of the present invention by at least including a transmit-receive antenna unit 305 configured with the ability to communicate with the UE and any other devices located in the coverage area of the corresponding cell, and a processor 310 operatively coupled to the transceiver antenna unit 305 and configured to implement the method of the first aspect of the present invention or any possible implementation of the first aspect of the present inventions. A Transmission Point (TRP) may be, but is not limited to, a Base Station (BS), an Access Point (AP), or a NodeB.

[0054] TRP 300 is shown in FIG. 2 in a relatively simplified, schematic form, so this figure does not show all the components actually contained in the TRP 300, but only those that make the present invention implemented. As is known, the TRP may contain other components not shown in the figure, such as a power supply, various interfaces, input/output means, interconnects, random access and read only memory storing instructions executable by the processor 310 for executing the method of the first aspect of the present invention or any possible implementation. the first aspect of the present invention, as well as the operating system, etc. The transceiver antenna unit 305 may include a transceiver and an antenna coupled to each other. The antenna can be implemented as a massive or extremely massive MIMO antenna array with a large number of antenna ports that supports hybrid analog and digital beamforming capabilities.

[0055] The processor 310 of the TRP 300 may be a central processing unit, a special purpose processor, another processing unit such as a graphics processing unit (GPU), or a combination thereof. Processor 310 may be implemented as a chip, such as a Field-Programmable Gate Array (FPGA), Application-Specific Integrated Circuit (ASIC), System-on-Chip, SoC), etc.

[0056] FIG. 3 illustrates a flowchart of a user terminal (UE) method for frequency selective transmit power control of an uplink (UL) channel to a Transmission Point (TRP) according to a fourth aspect of the present invention. The method begins and proceeds to step S200, which receives from the TRP an indication of a plurality of subbands obtained by dividing the available frequency range and to be used by the user terminal when transmitting the UL channel to the TRP with frequency selective transmit power control. The user terminal receives said indication from the TRP in whose cell the user terminal is currently located.

[0057] The received indication further includes, for each subband, a preset transmit power adjustment value for that subband to be applied by the user terminal to adjust the power in that subband when transmitting the UL channel to the TRP. If there is no need to perform transmit power trim for a particular subband, said indication for that subband may include a transmit power trim value δ of 0 dB, or in such a case, the indication for such subband may include no transmit power trim value δ , but thereby signal to the user terminal that there is no need to perform transmit power adjustment for this subband.

[0058] After completion of step S200, the method proceeds to execution of step S205, in which a UL channel with frequency selective power adjustment performed based on the received indication is transmitted to the TRP. The plurality of transmit power adjustment values in the indication control the transmitter PSD in the respective subbands (groups) of frequency resources (RB or RE). Therefore, the total PUSCH power according to the new Equation 1 below is the sum of the powers in each subband , limited above by the maximum transmitter power of the UE. Thus, the new UE transmit power equation for PUSCH (in linear terms) is the following Equation 1:

( Equation 1 ),

Where - linear value of the maximum permitted power transmission by the UE, this value may be signaled to the UE in a configuration message from the Transmit Point Point (TRP), alternatively, in some cases, this value may be the maximum transmitter output power of the UE,

- linear power value UE transmissions [decibel-milliwatt, dBm (logarithmic)] in th subband ( ), And

- the total number of frequency subbands in the resource allocation for PUSCH transmission.

[0059] Power UE transmission [dBm] in th subband ( ) is determined according to the following new Equation 2 proposed in this disclosure, which is based on a modification of the corresponding component of the equation for UL power control for 5G NR (see Section 7.1 in TS 38.214), which is applied to determine the transmit power [dBm] in the UE. The new Equation 2 can be written as follows:

( Equation 2 ),

Where - a target transmit/receive power spectral density (PSD) pre-configured by the transmit-receive point (TRP) and transmitted in the RRC configuration message for each 15 kHz physical resource block (PRB), subject to full compensation of path losses, and this target PSD can be considered as a reference power level P ₀ relative to which, as shown in FIG. 7 , in a possible embodiment of the present invention, the transmit power level in each subband is adjusted,

μ - numerological correction factor, μ ={0, 1, 2, 3, 4} to reflect the separation between individual orthogonal subcarrier frequencies, different from the reference separation of 15 kHz,

- number of RBs allocated for PUSCH,

- control coefficient for compensation of losses in the path ∈ [0,1], in the specified range the extreme value =0 means complete absence of compensation for losses in the path, and the other extreme value =1 means full compensation of losses in the path,

- estimation of path losses between TRP and UE,

- an optional (i.e. may not be present) power offset associated with the selected modulation and coding scheme (MCS), and

- the value of adjusting the transmission power specifically for of the th subband, signaled by the indication received in step S200, the number of values equal to the number of subranges obtained by partitioning; if value the indication does not specify that this value is 0 dB (i.e., PUSCH transmit power adjustment for the corresponding subband is not performed by the user terminal.

[0060] The above Equation 1 and Equation 2 are applied at the user terminal to perform frequency selective transmission power adjustment on the TRP of the UL channel (PUSCH). This power adjustment allows, as discussed above, to reduce inter-cell interference (eg, ICI interference generated by UE 400 transmissions to TRP 300 in cell 1 and negatively impacting cells 2 and 3, as illustrated in FIG. 5 ) and provide the illustrated Fig. 9 increase in uplink data rate by user terminals located close to the cell edge.

[0061] FIG. 4 illustrates a schematic diagram of a user terminal (UE, 400) according to a fifth aspect of the present invention, which is configured to implement the method according to the fourth aspect of the present invention by at least including a transmit/receive antenna unit 405 configured to implement communication with the TRP and any other devices within the coverage area of the corresponding cell, and a processor 410 operably coupled to the transmit/receive antenna unit 405 and configured to implement the method of the fourth aspect of the present invention or any possible implementation of the fourth aspect of the present invention. A User Terminal (UE) may be, but is not limited to, a mobile phone, tablet, laptop, personal computer, wearable electronic device (e.g., glasses, watch), AR/VR headset, Internet of Things (IoT) device, equipment placed in a vehicle or any other electronic device that supports mobile communications. The user terminal UE may be called something else, such as user equipment, user device, subscriber device, etc.

[0062] UE 400 is shown in FIG. 4 in a relatively simplified, schematic form, so this figure does not show all the components actually contained in the UE 400, but only those that make the present invention implemented. As is known, the UE may include other components not shown in the figure, such as a power supply, a battery, various interfaces, input/output means, interconnects, random access and read only memory storing instructions executable by the processor 410 for executing the method of the fourth aspect of the present invention or any a possible implementation of the fourth aspect of the present invention, as well as an operating system, etc. The transceiver antenna unit 405 may include a transceiver and an antenna coupled to each other. The antenna can be implemented as a massive or extremely massive MIMO antenna array with a large number of antenna ports that supports hybrid analog and digital beamforming capabilities.

[0063] The processor 410 of the UE 400 may be a central processing unit, a special purpose processor, another processing unit such as a graphics processing unit (GPU), or a combination thereof. Processor 410 may be implemented as a chip, such as a Field-Programmable Gate Array (FPGA), Application-Specific Integrated Circuit (ASIC), System-on-Chip, SoC), etc.

[0064] FIG. 5 illustrates a schematic diagram of a communication system 500 according to a seventh aspect of the present invention. Communications system 500 includes one TRP 300 that is installed with user terminals 400 in three deployed cells 1, 2, 3. Transmission point 300 may correspond to the TRP 300 that is described in detail above with reference to FIG. 3 , and each user terminal 400 may correspond to a UE 400, which is described in detail with reference to FIG. 4 , therefore a detailed description of the TRP 300 and UE 400 is again not given here. The communications system 500 may support any radio access technology (RAT), such as 4G LTE, 5G NR, 6G, or a combination thereof. In the latter case, i.e. When the communication system 500 supports multiple radio access technologies, the communication system 500 may employ dynamic frequency spectrum sharing.

[0065] Specific details shown in FIG. 5 should not be considered as a limitation of the present technology, since the system 500 may have a different architecture and be characterized/illustrated differently, for example, each cell of cell 1, cell 2, cell 3 may have its own TRP 300, the number of UEs 400 in the cells may different from that shown, cells 1, 2, 3 may be one larger cell, the shape and space covered by the cells may be different from those shown, etc.

[0066] FIG. 6 clearly illustrates the comparison between traditional MU-MIMO and MU-MIMO with frequency selective transmit power control proposed herein. The left side of this figure corresponds to the prior art, and the right side of the figure corresponds to the present invention, which uses frequency adaptive power control. As can be seen on the left side of the figure, the lack of dynamic power adjustment as a function of frequency results in the prior art in that the power spectral density of all uplink transmissions performed by the user terminals (UE1, UE2, UE3, UE4) is uneven. The right side shows the total power spectral density of the TRP received transmissions UE1, UE2, UE3, UE4 for which each of UE1, UE2, UE3, UE4 has previously applied frequency selective power adjustment according to the direction received from the TRP previously. Thus, thanks to the present invention, the transmission PSDs of individual UEs in different subbands can be dynamically adjusted depending on the number of UEs transmitting (according to the resource scheduling performed by the TRP) simultaneous transmissions in the respective subbands, but the total aggregate PSD of the transmissions of all UEs as perceived by the TRP receiver , remains uniform, resulting in reduced inter-cell interference and improved performance for UEs located near the cell edge.

[0067] FIG. 7 illustrates an exemplary scheme for adjusting the transmit power in each subband relative to the reference (target) transmit power level P ₀ common to all subbands. As mentioned above, typically the reference common transmit power level P ₀ for all subbands is the same as the target power spectral density ( PSD ₀ ) value that is determined for a single user in the subband, ie, for SU-MIMO. Therefore, to set the transmit power trim value δ for the frequency subband in this case relative to the overall reference power level P ₀ , this value can, in a non-limiting example, be set to δ=-10*log10(N) dB. The advantage of this implementation is that the adjustment in this case is carried out in a more precise manner, but a larger number of bits are used.

[0068] FIG. 8 illustrates an exemplary scheme for adjusting the transmit power in each subband relative to the adjusted transmit power level in the previous subband. A non-limiting example of setting the transmission power adjustment value δ for the (i+1) -th subband in this case could be: δ = 10*log10(N _i /N _{i +1} ) dB, where N _i is the number of MU-MIMO users in i th subband, and N _i+1 is the number of MU-MIMO users in the ( i+1 ) th subband. In this possible implementation, for the first subband (i.e., subband 0 in FIG. 8), the first trim value (i.e., the value δ ₀ in FIG. 8) would still be set relative to some level, for example, but without the limitation mentioned in relation to Fig. 7 reference (target) transmit power level P ₀ or the last adjusted transmit power level in the immediately previous time resource. Thus, the value of δ ₀ for subband 0 in FIG. 8 can be set as δ ₀ = -10*log10(N ₀ ) dB, where N ₀ is the number of MU-MIMO users in the 0th subband. The advantage of this implementation is that fewer bits are required to signal the power trim values δ.

[0069] In FIG. 9 shows experimental data obtained by the authors of the present disclosure in a network simulator and a representation in the form of cumulative distribution functions (CDF) plots of data rates for the UE in megabits per second (Mbps), clearly illustrating the beneficial effect of the application of the disclosed invention, namely the performance gain of user terminals (UEs) located close to cell boundaries (note in the figure the representative five percent UE allocation level in this regard) employing frequency selective transmit power control according to the present disclosure (see solid line), compared to the performance of a user terminal terminal (UE) not employing such frequency selective transmit power control (see dotted line).

[0070] The dynamic frequency selective transmit power adjustment disclosed herein reduces the overall power level of UL MU-MIMO data transmissions in frequency selective scheduling wireless systems with OFDMA. Thus, inter-cell interference is reduced, and the data transmission rate of user terminals located near cell boundaries increases.

[0071] The present invention may further be implemented as a storage medium storing processor-executable instructions that, when executed by a processor of a device equipped with a transceiver antenna unit, perform a method of any aspect of the disclosed invention or any possible implementation of the corresponding aspect. A storage medium may be any non-transitory computer readable medium, memory, storage area, storage device, etc., such as, but not limited to, a hard disk drive, optical media, semiconductor media, solid state drive (SSD), or similar to them.

[0072] Industrial applicability

[0073] The present invention can be applied to a TRP using massive MIMO antenna technology with a very large number of digital antenna ports (eg, ≥ 128). The invention can be used in a wireless system using advanced MU-MIMO transmission schemes, where multiple UEs transmit UL data signals simultaneously on the same frequencies. Moreover, the present invention can be applied to a wireless system using OFDMA technology for uplink multiple access. Finally, the present invention can be applied to a wireless cellular communication system with a massive MIMO antenna that uses the upper mid-band (10-13 GHz), operates in Time Division Duplex (TDD) mode (unpaired spectrum), and complies with 3GPP specifications.

[0074] At least one aspect of the disclosed technical solution may be implemented by an AI model. An AI-related function can be performed through persistent memory, RAM, and processor(s) (CPU, GPU, NPU). The processor(s) controls the processing of input data according to a predefined operating rule or artificial intelligence (AI) model stored in read-only memory and main memory. A predefined operating rule or artificial intelligence model is provided through learning. Here, “providing by learning” means that by applying a learning algorithm to a set of training data, a predefined operating rule or AI model with a desired characteristic is created (for example, an AI model for determining the values of various parameters (for example, the transmit power trim value δ) from the values of other parameters, or AI model to determine the scheme for dividing the available frequency range into subbands in a given case according to the values of certain communication parameters between TRP and UE). Such training may be performed within the device itself using the AI according to an embodiment, and/or may be implemented through a separate server/system.

[0075] The AI model may be a decision tree-based algorithm or consist of multiple neural network layers. Each layer has a set of weights and performs the layer's operation through a calculation based on the result of the calculation in the previous layer and applying a set of weights and other parameter values. Examples of decision tree-based algorithms include random forest, ensemble trees, etc., and examples of neural networks include, but are not limited to, convolutional neural network (CNN), deep neural network (DNN), recurrent neural network (RNN), Restricted Boltzmann Machine (RBM), Deep Belief Network (DBN), Bidirectional Network, Recurrent Deep Neural Network (BRDNN), Generative Adversarial Network (GAN), Transformer Networks, Deep Q-Net and so on.

[0076] A learning algorithm is a method of training a predetermined target device or target function based on a corresponding set of training data that causes, enables, controls, or provides an output of the target device or target function. Examples of learning algorithms include, but are not limited to, supervised learning, unsupervised learning, semi-supervised learning or reinforcement learning, and so on.

[0077] One skilled in the art will appreciate that the various illustrative logical blocks (functional blocks or modules) and steps (operations) used in embodiments of the disclosed technical solution may be implemented by electronic hardware, computer software, or a combination thereof. . Whether functions are implemented using hardware or software depends on the specific application and the design requirements of the overall system. One skilled in the art may employ various methods for implementing the described functions for each particular application, but such implementation should not be considered beyond the scope of the embodiments disclosed herein.

[0078] It should also be noted that the order of steps of any disclosed method is not strict, because some one or more steps may be rearranged in the actual order of execution and/or combined with another one or more steps, and/or divided into a larger number of sub-steps, for example, step S205, which transmits a frequency-selective UL channel to the TRP power performed based on the received indication may be divided into sub-steps in which the UE first performs frequency selective power adjustment of the transmitter and then performs UL transmission by the power adjusted transmitter. In addition, steps S100 and S105 may be performed such that first the transmission power trim values of different scheduled UEs are determined for an available frequency band, and then the boundaries of the subbands that are signaled to the UE as partitioned are determined (eg, by changing the transmit power trim values). subbands.

[0079] Throughout this application, reference to an element in the singular does not preclude the presence of multiple such elements in the actual implementation of the invention, and, conversely, reference to an element in the plural does not exclude the presence of only one such element in the actual implementation of the invention. Any specific value or range of values stated above should not be interpreted in a limiting sense, but rather such specific value or range of values should be considered to represent the midpoint of a specified larger range, up to approximately 50% on either side of the specified value or specified smaller range.

[0080] While this disclosure has been shown and described with reference to specific embodiments and examples thereof, those skilled in the art will understand that various changes in form and content may be made without departing from the spirit and scope of this disclosure as defined by the appended claims and their equivalents. In other words, the above detailed description is based on specific examples and possible implementations of the present invention, but it should not be interpreted to mean that only the explicitly disclosed implementations are feasible. It is intended that any change or substitution that could be made to this disclosure by one of ordinary skill in the art without creative and/or technical contribution shall be within the scope of protection, subject to equivalents, provided by the following claims.

Claims (38)

1. A transceiver point (TRP) method for frequency selective control of transmit power by a user terminal (UE) of an uplink (UL) channel, the method comprising the steps of: dividing (S100) the available frequency range into a plurality of sub-bands to be used by the user terminal when transmitting the UL channel to said TRP with frequency selective transmission power control; setting (S105), for each sub-band of the plurality of sub-bands, a transmission power adjustment value to be applied by the user terminal to adjust the power in the corresponding sub-band when transmitting the UL channel to the TRP; transmitting (S110) to the UE an indication of said plurality of subbands, wherein for each subband the indication additionally signals a transmission power adjustment value corresponding to that subband; And waits to receive or receives (S115) from the UE a transmission of a UL channel with frequency selective power adjustment based on the transmitted indication. 2. The method of claim 1, wherein said indication is a transmit power control (TPC) command in a downlink control information (DCI) message or a radio resource control (RRC) procedure configuration message. 3. The method of claim 1, wherein the UL channel is a physical uplink shared channel (PUSCH). 4. The method of claim 1, wherein dividing (S100) the available frequency band into a plurality of sub-bands and setting (S105) corresponding transmission power adjustment values is carried out by performing an RRC procedure between the TRP and the UE. 5. The method according to claim 1, in which the division (S100) of the available frequency range is performed into a plurality of equal-width sub-bands or into a plurality of different-width sub-bands, and the width of the sub-bands is specified by the number of resource elements (RE) or the number of resource blocks (RB) so such that the subband includes one or more REs or one or more RBs. 6. The method of claim 5, wherein performing partitioning (S100) of the available frequency range into a plurality of subbands includes forming a combined subband by combining two or more adjacent subbands of the same width in case the two or more adjacent subbands are specified (S105 ) the same transmission power adjustment value, with the beginning and end of the combined subband indicated: an index of the first RE or RB of the combined subband and an index of the last RE or RB of the combined subband; or the index of the first RE or RB of the combined subband and the number of RE or RB in the combined subband; or an index of the first RE or RB of the combined subband; and an index of the first RE or RB of the subband subsequent to said combined subband. 7. The method of claim 1, wherein setting (S105) for a sub-band of said plurality of sub-bands, a transmission power adjustment value is performed depending on the number of user terminals (UEs) transmitting simultaneously in the sub-band. 8. The method of claim 1, wherein the range of possible power trim values is expanded dynamically by using additional TPC command bit values in the DCI message or RRC configuration message indicating additional transmit power trim values. 9. The method according to claim 1, wherein the transmission power adjustment value in each subband is set (S105) relative to a common reference transmit power level for all subbands or relative to the transmit power level in the previous subband. 10. The method of claim 1, wherein the Transmission Point (TRP) is a base station (BS), an access point (AP), or a NodeB. 11. The method of claim 1, wherein the frequency selective power adjustment based on the transmitted indication modifies the power spectral density (PSD). 12. Transmission-reception point (TRP, 300), containing a transceiver antenna unit (305) and a processor (310), configured to implement the method according to any one of paragraphs. 1-11. 13. A storage medium storing instructions executable by the processor, which, when executed by the processor of a device equipped with a transceiver antenna unit, ensure the execution of the method according to any one of claims. 1-11. 14. A method implemented by a user terminal (UE) for frequency-selective control of transmit power of an uplink (UL) channel to a transmit-receiver point (TRP), the method comprising the steps of: receiving (S200) from said TRP an indication of a plurality of sub-bands obtained by dividing the available frequency range and to be used by the user terminal when transmitting a UL channel to said TRP with frequency selective transmit power control, wherein for each sub-band the said indication further signals a power trim value specified for the sub-band transmissions to be used by the user terminal to adjust power in this subband when transmitting the UL channel to said TRP; And transmitting (S205) to said TRP UL channel to perform frequency selective power adjustment based on the received indication. 15. The method of claim 14, wherein said indication is a transmit power control (TPC) command in a downlink control information (DCI) message or a radio resource control (RRC) procedure configuration message between the TRP and the UE. 16. The method of claim 14, wherein the UL channel is a physical uplink shared channel (PUSCH). 17. The method of claim 14, wherein the plurality of subbands and the corresponding plurality of transmit power adjustment values are configured by performing an RRC procedure between the TRP and the UE. 18. The method of claim 14, wherein the plurality of subbands includes equal-width subbands and/or different-width subbands, wherein the width of the subbands is specified in the indication by the number of resource elements (RE) or the number of resource blocks (RB) such that the subband includes one or more REs or one or more RBs. 19. The method of claim 18, wherein the plurality of subbands includes a combined subband, the start and end of the combined subband being indicated by: an index of the first RE or RB of the combined subband and an index of the last RE or RB of the combined subband; or the index of the first RE or RB of the combined subband and the number of RE or RB in the combined subband; or an index of the first RE or RB of the combined subband; and an index of the first RE or RB of the subband subsequent to said combined subband. 20. The method of claim 14, wherein, for a subband of said plurality of subbands, the transmission power adjustment value indicated in said indication is set depending on the number of other UEs transmitting simultaneously with said UE in that subband. 21. The method of claim 14, wherein the range of possible power trim values is expanded dynamically by using additional TPC command bit values in the DCI message or RRC configuration message indicating additional transmit power trim values. 22. The method according to claim 14, in which the transmit power adjustment value in each subband is set relative to a reference transmit power level common to all subbands or relative to the transmit power level in the previous subband. 23. The method of claim 14, wherein the frequency selective power adjustment based on the received indication modifies the power spectral density (PSD). 24. A user terminal (UE, 400) comprising a transceiver antenna unit (405) and a processor (410) configured to implement the method according to any one of claims. 14-23. 25. A storage medium storing instructions executable by the processor, which, when executed by the processor of a device equipped with a transceiver antenna unit, ensure execution of the method according to any one of claims. 14-23. 26. A communications system (500) comprising one or more transmit-receiver points (TRPs, 300) of claim 12 and one or more user terminals (UE, 400) of claim 24.