Method and apparatus for receiving downlink data in a wireless communication system

Abstract

This disclosure relates to fifth-generation (5G) or sixth-generation (6G) communication systems to support higher data rates beyond fourth-generation (4G) communication systems such as Long Term Evolution (LTE). A method performed by a user equipment (UE) in a wireless communication system is provided. The method includes: receiving a first channel state information reference signal (CSI-RS) from each of at least one first transmit / receive point (TRP); receiving a second CSI-RS from a second TRP; estimating at least one first phase value for each of the first CSI-RS received from each of the at least one first TRP based on the first CSI-RS received from each of the at least one first TRP; estimating a second phase value based on the second CSI-RS; and transmitting a first detection reference signal (SRS) and a second SRS to each of the at least one first TRP on different adjacent symbols, based on phase shifts using the at least one first phase value and the second phase value.

Description

Technical Field

[0001] This disclosure relates to a wireless communication system. More specifically, this disclosure relates to apparatus and methods for enabling a user equipment (UE) to receive downlink data during coordinated transmission. Background Technology

[0002] Looking back at the evolution of mobile communications over several generations, technologies have been developed primarily for human services such as voice, multimedia, and data. Following the commercialization of fifth-generation (5G) communication systems, an explosive number of connected devices are expected to be connected to communication networks. Examples of network objects include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to evolve into various form factors, including augmented reality glasses, virtual reality headsets, and holographic devices. In the sixth-generation (6G) era, efforts are underway to develop improved 6G communication systems to connect hundreds of billions of devices and objects to provide a wide range of services. For this purpose, 6G communication systems are often referred to as super 5G systems.

[0003] The 6G communication system, expected to be realized around 2030, will have a maximum transmission speed of terabits per second (bps) and a wireless latency of 100 microseconds (μsec), which is 50 times faster than the 5G communication system and one-tenth of the wireless latency.

[0004] To achieve these high data rates and ultra-low latency, 6G communication systems are being considered for implementation in terahertz bands (e.g., the 95 GHz to 3 THz band). Compared to the millimeter-wave (mmWave) bands introduced in 5G, the terahertz band is expected to suffer from more severe path loss and atmospheric absorption, which will increase the importance of technologies to ensure signal arrival or coverage. Key technologies for ensuring coverage include radio frequency (RF) equipment, antennas, new waveforms that outperform orthogonal frequency division multiplexing (OFDM) in terms of coverage, beamforming, and multi-antenna transmission technologies such as massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, and massive MIMO. Furthermore, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing using orbital angular momentum (OAM), and reconfigurable smart surfaces (RIS) are being discussed to improve the coverage of terahertz band signals.

[0005] Furthermore, to improve frequency efficiency and enhance system networks, 6G communication systems will utilize full-duplex technology, allowing uplink (terminal transmission) and downlink (base station transmission) to simultaneously utilize the same frequency resources; integrated satellite and High Altitude Platform Station (HAPS) network technologies; innovative network architecture technologies that support mobile base stations and enable network operation optimization and automation; dynamic spectrum sharing technology, enabling conflict avoidance based on spectrum usage prediction; AI-based communication technologies that utilize AI from the technology design stage and achieve system optimization through embedded end-to-end AI support functions; and next-generation distributed computing technologies that leverage ultra-high-performance communication and computing resources (Multi-access Edge Computing (MEC), cloud, etc.) to achieve complex services beyond the limitations of terminal computing capabilities. In addition, efforts are underway to further enhance connectivity between devices, optimize networks, promote the software-defined networking of network entities, and increase the openness of mobile communications through the design of new protocols to be used in 6G communication systems, the implementation of hardware-based security environments, the development of mechanisms for secure data utilization, and the development of technologies for maintaining privacy.

[0006] This research and development of 6G communication systems promises to realize the next level of hyper-connectivity, encompassing not only connectivity between things but also connectivity between people and things. Specifically, it is expected that 6G communication systems will enable services such as truly immersive extended reality (XR), high-fidelity mobile holograms, and digital replicas. Furthermore, 6G communication systems will provide services such as remote surgery, industrial automation, and emergency response to enhance safety and reliability, and will be applied in various fields such as industry, healthcare, automotive, and home appliances.

[0007] In particular, due to the short packet arrival times of uplink (UL) extended reality (XR) services, existing technologies that can only allocate UL authorization for a single Hybrid Automatic Repeat Request (HARQ) process may introduce additional latency when the UL transmission period and UL service arrival period are similar. Various technologies for uplink transmission and retransmission are being considered to address these issues and achieve seamless communication between the base station and the terminal.

[0008] The above information is presented as background information only to aid in understanding this disclosure. No determination or assertion is made regarding whether any of the above content can be used as prior art with respect to this disclosure. Summary of the Invention

[0009] Solution to the problem

[0010] The aspects of this disclosure will at least address the aforementioned problems and / or disadvantages, and provide at least the following advantages. Therefore, one aspect of this disclosure is to provide an apparatus and method capable of performing effective signal transmission / reception in a wireless communication system.

[0011] Another aspect of this disclosure is to provide an apparatus and method for maximizing the gain generated by downlink data reception during coordinated transmission.

[0012] Other aspects will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the embodiments presented.

[0013] According to one aspect of this disclosure, a method performed by a user equipment (UE) in a wireless communication system is provided. The method includes: receiving a first channel state information reference signal (CSI-RS) from each of at least one first transmit / receive point (TRP); receiving a second CSI-RS from a second TRP; estimating at least one first phase value for each of the first CSI-RS received from each of the at least one first TRP based on the first CSI-RS received from each of the at least one first TRP; estimating a second phase value based on the second CSI-RS; and transmitting a first detection reference signal (SRS) and a second SRS to each of the at least one first TRP on different adjacent symbols, based on phase shifts using the at least one first phase value and the second phase value.

[0014] According to another aspect of this disclosure, a method performed by a first transmitting / receiving point (TRP) in a wireless communication system is provided. The method includes: transmitting a first channel state information reference signal (CSI-RS) to a user equipment (UE); receiving, from the UE, a first detection reference signal (SRS) and a second SRS on different adjacent symbols, respectively, based on phase shifts using a first phase value of the first CSI-RS estimated based on the first CSI-RS and a second phase value of the second CSI-RS estimated based on a second TRP; applying phase compensation between the first TRP and the second TRP to first downlink data using the first SRS and the second SRS received based on the phase shifts of the first and second phase values; and transmitting the first downlink data to which the phase compensation was applied to the UE.

[0015] According to another aspect of this disclosure, a user equipment (UE) in a wireless communication system is provided. The UE includes a transceiver and a controller coupled to the transceiver, the controller being configured to receive a first channel state information reference signal (CSI-RS) from each of at least one first transmit / receive point (TRP), receive a second CSI-RS from a second TRP, estimate at least one first phase value for each of the first CSI-RS received from each of at least one first TRP based on the first CSI-RS received from each of at least one first TRP, estimate a second phase value based on the second CSI-RS, and transmit a first sounding reference signal (SRS) and a second SRS to each of at least one first TRP on different adjacent symbols based on phase shifts using at least one first phase value and the second phase value.

[0016] According to another aspect of this disclosure, a first transmit / receive point (TRP) is provided in a wireless communication system. The first TRP includes a transceiver and a controller coupled to the transceiver, the controller being configured to transmit a first channel state information reference signal (CSI-RS) to a user equipment (UE); receive a first sounding reference signal (SRS) and a second SRS on different adjacent symbols from the UE based on phase shifts using a first phase value of the first CSI-RS estimated based on the first CSI-RS and a second phase value of the second CSI-RS estimated based on a second TRP; apply phase compensation between the first TRP and the second TRP to first downlink data based on the phase shifts of the first and second SRS received using the first and second phase values; and transmit the phase-compensated first downlink data to the UE.

[0017] This disclosure provides an apparatus and method for effectively providing services in a wireless communication system.

[0018] This disclosure provides an apparatus and method for performing effective signal transmission / reception in a wireless communication system.

[0019] Other aspects, advantages, and salient features of this disclosure will become apparent to those skilled in the art from the following detailed description of various embodiments of the disclosure taken in conjunction with the accompanying drawings. Attached Figure Description

[0020] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0021] Figure 1 A wireless environment network in a wireless communication system according to an embodiment of the present disclosure is illustrated;

[0022] Figure 2 The functional configuration of a base station in a wireless communication system according to an embodiment of the present disclosure is shown;

[0023] Figure 3 A functional configuration of a UE in a wireless communication system according to an embodiment of the present disclosure is shown;

[0024] Figure 4 An example of a radio resource domain in a wireless communication system according to an embodiment of the present disclosure is shown;

[0025] Figure 5 An example of data transmission / reception based on coherent joint transmission (CJT) according to an embodiment of this disclosure is shown;

[0026] Figure 6 Examples of problems that may occur if the phase difference between signals received by the receiver is fed back from the codebook, according to embodiments of the present disclosure, are shown.

[0027] Figure 7 An example of a scheme for feedback of phase difference between signals received by a UE according to an embodiment of the present disclosure is shown;

[0028] Figure 8 An example of a scheme for feedback of phase difference between signals received by a UE according to an embodiment of the present disclosure is shown;

[0029] Figure 9 An example of CSI-RS resource allocation according to an embodiment of this disclosure is shown;

[0030] Figure 10 An example of SRS transport resource allocation according to an embodiment of the present disclosure is shown;

[0031] Figure 11 An example of a scheme for feedback of phase difference between signals received by a UE according to an embodiment of the present disclosure is shown;

[0032] Figure 12 An example of CSI-RS resource allocation according to an embodiment of this disclosure is shown;

[0033] Figure 13 An example of SRS transport resource allocation according to an embodiment of the present disclosure is shown;

[0034] Figure 14 An example of a method for calculating a phase difference according to an embodiment of the present disclosure is shown;

[0035] Figure 15 Other examples of methods for calculating phase differences according to embodiments of the present disclosure are shown;

[0036] Figure 16 and Figure 17 Examples of methods for determining the validity of a phase difference calculated by a TRP, according to various embodiments of the present disclosure, are shown;

[0037] Figure 18 An example of a method for determining the validity of a phase difference calculated by a TRP, according to an embodiment of the present disclosure, is shown;

[0038] Figure 19 An example of a calibrationRSList configuration according to an embodiment of this disclosure is shown;

[0039] Figure 20 An example of configuring the necessary RRC configuration parameters according to embodiments of this disclosure is shown;

[0040] Figure 21 An example of a feedback scheme for phase calibration between received signals is shown according to an embodiment of the present disclosure;

[0041] Figure 22 This is a flowchart illustrating an example of a method for performing an operation of a UE according to embodiments of this disclosure; and

[0042] Figure 23 This is a flowchart illustrating an example of a method for performing a TRP operation according to an embodiment of the present disclosure.

[0043] Throughout the accompanying drawings, the same reference numerals will be understood to refer to the same parts, components, and structures. Detailed Implementation

[0044] The following description with reference to the accompanying drawings is intended to aid in a full understanding of the various embodiments of this disclosure as defined by the claims and their equivalents. It includes various specific details to aid understanding, but these are considered exemplary only. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the various embodiments described herein without departing from the scope and spirit of this disclosure. Additionally, for clarity and brevity, descriptions of well-known functions and structures may be omitted.

[0045] The terms and words used in the following description and claims are not limited to their literal meaning, but are used by the inventors only to enable a clear and consistent understanding of this disclosure. Therefore, those skilled in the art should understand that the following description of various embodiments of this disclosure is for illustrative purposes only and is not intended to limit the scope of this disclosure as defined by the appended claims and their equivalents.

[0046] It should be understood that, unless the context clearly specifies otherwise, the singular forms “a,” “an,” and “the” include plural indicators. Thus, for example, a reference to “component surface” includes a reference to one or more such surfaces.

[0047] In the following description, various embodiments of this disclosure will be based on a hardware approach. However, the various embodiments of this disclosure include techniques using both hardware and software, and therefore, a software perspective is not excluded from the various embodiments of this disclosure. Furthermore, for ease of description, terms referring to network entities, terms referring to device elements, etc., are used illustratively. Therefore, this disclosure is not limited to the terminology described below, and other terms referring to subjects with equivalent technical meanings may be used.

[0048] Furthermore, various embodiments of this disclosure will be described using terminology adopted in some communication standards (e.g., the 3rd Generation Partnership Project (3GPP) and the European Telecommunications Standards Institute (ETSI)), but these are for illustrative purposes only. The various embodiments of this disclosure can be readily applied to other communication systems with modifications.

[0049] Furthermore, in this disclosure, the expressions “greater than” or “less than” are used to determine whether a particular condition is met or achieved, but this is only intended to be illustrative and does not exclude “greater than or equal to” or “equal to or less than”. A condition indicated by the expression “greater than or equal to” can be replaced by a condition indicated by “greater than”, a condition indicated by the expression “equal to or less than” can be replaced by a condition indicated by “less than”, and a condition indicated by “greater than and equal to or less than” can be replaced by a condition indicated by “greater than and less than”.

[0050] In the following description, for ease of description, terms referring to signals, channels, control information, network entities, and device elements are used illustratively. Therefore, this disclosure is not limited to the terms described below, and other terms with equivalent technical meanings may be used.

[0051] It should be understood that each box in a flowchart and the combination of flowcharts can be executed by one or more computer programs including instructions. The entirety of one or more computer programs can be stored in a single memory device, or one or more computer programs can be divided into different parts stored in multiple different memory devices.

[0052] Any function or operation described herein can be processed by a processor or a combination of processors. A processor or a combination of processors is circuitry that performs processing and includes, for example, an application processor (AP, such as a central processing unit (CPU)), a communication processor (CP, such as a modem), a graphics processing unit (GPU), a neural processing unit (NPU) (e.g., an artificial intelligence (AI) chip), a Wi-Fi chip, Bluetooth, etc. ®Chips, Global Positioning System (GPS) chips, Near Field Communication (NFC) chips, connectivity chips, sensor controllers, touch controllers, fingerprint sensor controllers, display driver integrated circuits (ICs), audio codec chips, Universal Serial Bus (USB) controllers, camera controllers, image processing ICs, microprocessor units (MPUs), system-on-a-chip (SoCs), ICs, etc.

[0053] Figure 1 A wireless environment network in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0054] refer to Figure 1 An example is shown of a base station 110, a first UE 120, and a second UE 130, which are part of a node using a radio channel in a wireless communication system. Although Figure 1 Only one base station is shown, but base stations that are the same as or similar to base station 110 may also be included.

[0055] Base station 110 is network infrastructure configured to provide wireless connectivity to UEs 120 and 130. Base station 110 has a coverage area, which is defined as a predetermined geographical area based on the distance a signal can be transmitted to. In addition to "base station", base station 110 may also be referred to as "access point (AP)," "eNodeB (eNB)," "fifth-generation node (5G node)," "next-generation nodeB (gNB)," "wireless point," "transmit / receive point (TRP)," or other terms with equivalent technical meanings.

[0056] Each of the first UE 120 and the second UE 130 refers to a device used by a user to communicate with the base station 110 via a radio channel. In some cases, at least one of the first UE 120 and the second UE 130 can operate without user intervention. That is, at least one of the first UE 120 and the second UE 130 can be a device configured to perform machine-type communication (MTC) without being carried by a user. In addition to "user equipment (UE)," each of the first UE 120 and the second UE 130 may also be referred to as a "terminal," "mobile station," "subscriber station," "remote terminal," "wireless terminal," "user equipment," or other terms with equivalent technical meanings.

[0057] Base station 110, first UE 120, and second UE 130 can transmit and receive radio signals in millimeter-wave frequency bands (e.g., 28 GHz, 30 GHz, 38 GHz, and 60 GHz). Base station 110, first UE 120, and second UE 130 can perform beamforming to improve channel gain. As used herein, beamforming can include transmit beamforming and receive beamforming. That is, base station 110, first UE 120, and second UE 130 can assign directionality to the transmitted or received signals. To this end, base station 110 and UEs 120 and 130 can select serving beams 112, 113, 121, and 131 through beam search or beam management procedures. After selecting a serving beam, subsequent communication can be performed using resources that have a quasi-co-located (QCL) relationship with the resource used to transmit the serving beam.

[0058] If the large-scale characteristics of the channel used to transmit symbols at the first antenna port can be inferred from the channel used to transmit symbols at the second antenna port, then the QCL relationship between the first and second antenna ports can be evaluated. For example, large-scale characteristics include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial receiver parameters.

[0059] Figure 2 The functional configuration of a base station in a wireless communication system according to an embodiment of the present disclosure is shown. Figure 2 The configuration shown can be understood as the configuration of base station 110. As used herein, terms such as “unit” and “device” refer to a unit configured to perform at least one function or operation, and can be implemented as hardware, software, or a combination of hardware and software.

[0060] Reference Figure 2 The base station includes a wireless communication unit 210, a backhaul communication unit 220, a storage unit 230, and a control unit 240.

[0061] The wireless communication unit 210 performs functions for transmitting / receiving signals via a radio channel. For example, the wireless communication unit 210 performs functions for converting between baseband signals and bit strings according to the system's physical layer specifications. For example, during data transmission, the wireless communication unit 210 encodes and modulates the transmitted bit string to generate complex symbols. Additionally, during data reception, the wireless communication unit 210 demodulates and decodes the baseband signal to recover the received bit string.

[0062] Furthermore, the wireless communication unit 210 up-converts the baseband signal to a radio frequency (RF) band signal, transmits the signal through an antenna, and down-converts the RF band signal received through the antenna back to a baseband signal. For this purpose, the wireless communication unit 210 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital-to-analog (DAC) converter, an analog-to-digital (ADC) converter, etc. Additionally, the wireless communication unit 210 may include multiple transmit / receive paths. Moreover, the wireless communication unit 210 may include at least one antenna array comprising multiple antenna elements.

[0063] In terms of hardware, the wireless communication unit 210 may include digital units and analog units. The analog unit may include multiple sub-units depending on the operating power, operating frequency, etc. The digital unit may be implemented as at least one processor (e.g., a digital signal processor (DSP)).

[0064] As described above, the wireless communication unit 210 transmits and receives signals. Therefore, all or part of the wireless communication unit 210 may be referred to as a "transmitter," a "receiver," or a "transceiver." Furthermore, as will be described below, transmission and reception performed via a radio channel will be used in the sense of including the aforementioned processing performed by the wireless communication unit 210.

[0065] The backhaul communication unit 220 provides an interface for performing communication with other nodes within the network. That is, the backhaul communication unit 220 converts bit strings sent from the base station to other nodes (e.g., other access nodes, other base stations, upper-layer nodes, core network, etc.) into physical signals, and converts physical signals received from other nodes into bit strings.

[0066] Storage unit 230 stores data such as default programs, application programs, and configuration information for base station operation. Storage unit 230 can be configured as volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. Storage unit 230 also provides stored data upon request from control unit 240.

[0067] Control unit 240 (or controller) controls the overall operation of the base station. For example, control unit 240 sends and receives signals via wireless communication unit 210 or backhaul communication unit 220. Additionally, control unit 240 records data in storage unit 230 and reads that data. Control unit 240 can also perform the functions of the protocol stack required by the communication specification. According to another example of the implementation, the protocol stack may be included in wireless communication unit 210. For this purpose, control unit 240 may include at least one processor.

[0068] According to various embodiments, the control unit 240 can control the base station to perform operations according to various embodiments described later.

[0069] Figure 3 The functional configuration of a UE in a wireless communication system according to an embodiment of the present disclosure is shown. Figure 3 The configuration shown can be understood as the configuration of UE 120 or 130. As used herein, terms such as “unit” and “device” refer to a unit configured to perform at least one function or operation and can be implemented as hardware, software, or a combination of hardware and software.

[0070] Reference Figure 3 The UE includes a communication unit 310, a storage unit 320, and a control unit 330.

[0071] Communication unit 310 performs functions for transmitting / receiving signals via a radio channel. For example, communication unit 310 performs functions for converting between baseband signals and bit strings according to the system's physical layer specifications. For instance, during data transmission, communication unit 310 encodes and modulates the transmitted bit string to generate complex symbols. Additionally, during data reception, communication unit 310 demodulates and decodes the baseband signal to recover the received bit string. Furthermore, communication unit 310 up-converts the baseband signal to an RF band signal, transmits the signal through an antenna, and down-converts the RF band signal received through the antenna back to a baseband signal. For example, communication unit 310 includes a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0072] Additionally, the communication unit 310 includes multiple transmit / receive paths. Furthermore, the communication unit 310 may include at least one antenna array comprising multiple antenna elements. In terms of hardware, the communication unit 310 may include digital and analog circuitry (e.g., a radio frequency integrated circuit (RFIC)). The digital and analog circuitry can be implemented in a single package. Furthermore, the communication unit 310 may include multiple RF chains. Additionally, the communication unit 310 may perform beamforming.

[0073] As described above, the communication unit 310 transmits and receives signals. Therefore, all or part of the communication unit 310 may be referred to as a "transmitter," a "receiver," or a "transceiver." Furthermore, as will be described below, transmission and reception performed via a radio channel will be used in the sense of including the aforementioned processing performed by the communication unit 310.

[0074] Storage unit 320 stores data such as default programs, application programs, and configuration information for UE operation. Storage unit 320 can be configured as volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. Storage unit 320 also provides stored data upon request from control unit 330.

[0075] Control unit 330 (or controller) controls the overall operation of the UE. For example, control unit 330 sends and receives signals via communication unit 310. Additionally, control unit 330 records data in storage unit 320 and reads that data. Control unit 330 can also perform the functions of the protocol stack required by the communication specifications. For this purpose, control unit 330 may include at least one processor or microprocessor, or may be part of a processor. Furthermore, communication unit 310 and a portion of control unit 330 may be referred to as a communication processor (CP).

[0076] According to various embodiments, the control unit 330 can control the UE to perform operations according to various embodiments described later.

[0077] Figure 4 An example of a radio resource domain in a wireless communication system according to embodiments of the present disclosure is shown. In various embodiments of the present disclosure, the radio resource domain may include a time-frequency domain structure. According to embodiments, the wireless communication system may include a novel radio (NR) communication system.

[0078] Reference Figure 4 In the radio resource domain, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. Radio frame 404 has a length of 10 ms. Radio frame 404 can be a time-domain portion comprising ten subframes. Subframe 403 has a length of 1 ms. The configuration unit in the time domain can be an orthogonal frequency division multiplexing (OFDM) and / or discrete Fourier transform (DFT)-extended-OFDM (DFT-s-OFDM) symbol, and a set of N symb One OFDM and / or DFT-s-OFDM symbol 401 can constitute one time slot 402. According to various embodiments of this disclosure, OFDM symbols may include symbols associated with transmitting / receiving signals using an OFDM multiplexing scheme, and DFT-s-OFDM symbols may include symbols associated with transmitting / receiving signals using a DFT-s-OFDM or single-carrier frequency division multiple access (SC-FDMA) multiplexing scheme. The smallest transmission unit in the frequency domain is a subcarrier, and a total of N scBW Each subcarrier 405 can constitute a carrier bandwidth, which forms a resource grid. Furthermore, although embodiments relating to downlink signal transmission / reception will be described in this disclosure for ease of description, they are also applicable to embodiments relating to uplink signal transmission / reception.

[0079] According to an embodiment, the number and length of time slots 402 constituting a subframe 403 can vary depending on the subcarrier spacing. This subcarrier spacing can be referred to as a parameter set. For example, the subcarrier spacing, the number of time slots included in a subframe, the length of the time slots, and the length of the subframe can be variably configured. For instance, if the subcarrier spacing (SCS) in an NR communication system is 15 kHz, then one time slot 402 constitutes one subframe 403, and each of time slot 402 and subframe 403 has a length of 1 ms. Furthermore, for example, if the subcarrier spacing is 30 kHz, then two time slots can constitute one subframe 403. The time slot has a length of 0.5 ms, and the subframe has a length of 1 ms.

[0080] According to embodiments, the subcarrier spacing, the number of time slots included in a subframe, the length of the time slots, and the length of the subframe can be variably applied depending on the communication system. For example, in the case of a Long Term Evolution (LTE) system, the subcarrier spacing is 15 kHz, and two time slots constitute one subframe. In this case, the time slots can have a length of 0.5 ms, and the subframes can have a length of 1 ms. As another example, in the case of an NR system, the subcarrier spacing ( The frequency can be one of 15kHz, 30kHz, 60kHz, 120kHz, 240kHz, 480kHz, and 960kHz, and the number of time slots included in a subframe can be 1, 2, 4, 8, 16, 32, or 64, depending on the subcarrier spacing. ).

[0081] The basic unit of a resource in the time-frequency domain can be a resource element (RE) 406, which can be represented by an OFDM symbol index and a subcarrier index. A resource block can include multiple resource elements. In an NR system, a resource block (RB) (or physical resource block (PRB)) 407 can be defined as N in the frequency domain. SC RB 408 consecutive subcarriers. The number of subcarriers can be N. SC RB =12. The frequency domain can include shared resource blocks (CRBs). PRBs can be defined in the bandwidth portion (BWP) of the frequency domain. CRB and PRB numbers can be determined based on the subcarrier spacing. In LTE systems, RBs can be derived from N in the time domain. symb A continuous OFDM symbol and N in the frequency domain SC RB Defined by consecutive subcarriers.

[0082] In NR and / or LTE systems, scheduling information regarding downlink or uplink data can be transmitted from base station 110 to UE 120 via downlink control information (DCI). According to various embodiments of this disclosure, DCI can be defined in various formats, and each format can indicate whether the DCI includes scheduling information regarding uplink data (e.g., UL grant), whether the DCI includes scheduling information regarding downlink data (e.g., DL resource allocation), whether the DCI is a compact DCI with a small control information size or a back-off DCI, whether spatial multiplexing of multiple antennas is applied, and / or whether the DCI is used for power control. For example, NR DCI format 1_0 or NR DCI format 1_1 includes scheduling information regarding downlink data. Additionally, for example, NR DCI format 0_0 or NR DCI format 0_1 ​​includes scheduling information regarding uplink data.

[0083] As mentioned above, Figure 4 An example of downlink and uplink time slot structure in a wireless communication system is shown. Specifically, Figure 4 The structure of the resource grid in an NR system is illustrated. (Reference) Figure 4 A time slot can include multiple Orthogonal Frequency Division Multiplexing (OFDM) symbols in the time domain and multiple resource blocks (RBs) in the frequency domain. The signal can include a portion or all of the resource grid. Furthermore, the number of OFDM symbols included in a time slot can vary depending on the length of the cyclic prefix (CP). Although for ease of description... Figure 4 The illustration shows a time slot comprising 14 OFDM symbols, but the symbol configuration is not specified in conjunction with the signals mentioned in this disclosure. Furthermore, the modulation scheme for the generated signals is not specified as quadrature amplitude modulation (QAM) of a particular value, and can follow modulation schemes of various communication specifications, such as binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK).

[0084] According to various embodiments of this disclosure, operations for controlling uplink retransmissions to achieve effective signal transmission are described based on LTE or NR communication systems. However, this disclosure is not limited thereto and can be applied to various wireless communication systems for transmitting downlink or uplink control information. Furthermore, it is apparent that this disclosure can be applied not only to licensed frequency bands but also to unlicensed frequency bands if desired.

[0085] In the following text, as used herein, higher-layer signaling or higher-level signals may correspond to signal transmission methods in which base station 110 transmits signals to UE 120 via a physical layer downlink data channel, or UE 120 transmits signals to base station 110 via a physical layer uplink data channel. According to embodiments, higher-layer signaling may include at least one of Radio Resource Control (RRC) signaling, and signaling based on the F1 interface between a centralized unit (CU) and a distributed unit (DU), and signal transmission methods in which signals are transmitted via a Media Access Control (MAC) control element (MAC CE). Additionally, according to embodiments, higher-layer signaling or higher-level signals may include system information (e.g., a System Information Block (SIB)) commonly transmitted to multiple UEs 120.

[0086] In 5G wireless communication systems, a Synchronization Signal Block (SSB) (also known as an SS block, SS / PBCH block, etc.) can be transmitted for initial access. The SSB can include a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH). Additionally, the SSB can include information about the beams used by the base station to transmit signals, and as used herein, an SSB index or SSB can refer to at least one beam. During the initial access procedure of the UE's initial access to the system, the UE can obtain downlink time-domain and frequency-domain synchronization from the synchronization signals through a cell search procedure, and can also obtain the cell ID. The synchronization signals can include the PSS and SSS. The UE can receive a PCBH including a Primary Information Block (MIB) from the base station to obtain system information about transmission / reception, such as system bandwidth or related control information, and basic parameter values. The UE can perform decoding of the Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel (PDSCH) based on the received PBCH to obtain a System Information Block (SIB). The UE can then exchange identities with the base station through a random access procedure and can initially access the network through registration, authentication, and other steps.

[0087] As described above, a time slot can include 14 symbols. According to various embodiments of this disclosure, uplink-downlink configuration of symbols and / or time slots can be configured in a 5G communication system in three steps.

[0088] In the first method, the uplink-downlink configuration of symbols and / or time slots can be configured semi-statically using cell-specific configuration information based on symbol-level system information. More specifically, the cell-specific uplink-downlink configuration information via system information can include uplink-downlink mode information and subcarrier information used as a reference. The uplink-downlink mode information can indicate periodicity, the number of consecutive downlink time slots starting from the beginning of each mode, the number of symbols in the next time slot, the number of consecutive uplink time slots starting from the end of the mode, and the number of symbols in the next time slot. Time slots and symbols not indicated by uplink and downlink can be considered flexible time slots / symbols.

[0089] In the second approach, flexible time slots or time slots including flexible symbols can be indicated by the number of consecutive downlink symbols starting from the beginning symbol of each time slot and the number of consecutive uplink symbols starting from the end of the time slot, or by the entire downlink or the entire uplink of the time slot, using user-specific configuration information based on dedicated higher-layer signaling.

[0090] In the third method, to dynamically change the downlink and uplink signal transmission segments, a slot format indicator (SFI) included in the downlink control channel can be used to indicate whether a symbol designated as a flexible symbol in each slot (e.g., a symbol not indicated by downlink and uplink) is a downlink symbol, an uplink symbol, or a flexible symbol. The slot format indicator can select an index from a table of uplink / downlink configurations pre-configured for 14 symbols in a slot.

[0091] In 5G NR, coherent joint transmission (CJT) and incoherent joint transmission (NCJT) can be defined for DL / UL reception / transmission from / to the UE's multiple transmit / receive points (TRP).

[0092] CJT in 5G NR is one of the core technologies that can improve the throughput of 5G NR, and it is known as Coordinated Multipoint (CoMP) in 4G LTE. In the case of CJT, each TRP sends the same data to the receiver, and the receiver (e.g., UE) overlaps and receives the modulated signals of the data sent by each TRP, and the receiver can improve SINR performance through this, thereby improving reception performance.

[0093] Figure 5 An example of CJT-based data transmission / reception according to an embodiment of this disclosure is shown.

[0094] refer to Figure 5TRP 1 520 and TRP 2 525 can transmit the same data to UE 510, and UE 510 can overlap and receive modulated signals of the same data transmitted from TRP 1 520 and TRP 2 525. The signal received by UE 510 can be expressed as the following equation:

[0095] Equation 1

[0096] In the above formula, H1 refers to Figure 5 H1 refers to the channel matrix from TRP 1 520 to UE 510, and H2 refers to the channel matrix from TRP 2 525 to UE 510. Additionally, W refers to the precoding matrix used by TRP 1 520 and TRP 2 525 to transmit downlink signals to UE 510.

[0097] In the case of CJT, when the receiver receives signals transmitted from each TRP, the performance gain of CJT can be maximized by eliminating the phase difference between the signals received by the receiver. Therefore, in the case of CJT, the absence of a phase difference between the signals received by the receiver may be an important requirement. However, phase differences may occur in practical systems due to the following reasons:

[0098] (1) During CJT operation, each TRP can use a different local oscillator.

[0099] (2) During CJT operation, the antenna modules of each TRP can have different phase drift values.

[0100] (3) During CJT operation, the propagation delay of signals sent from each TRP before reaching the receiver may be different from each other.

[0101] Thus, in order to compensate for the phase difference between signals received by the receiver that may occur in a real CJT system, phase calibration (or phase compensation) may be required.

[0102] This section will briefly describe trends in specifications related to techniques used to compensate for phase differences between signals received by the receiver, which may occur in CJT systems. Prior to version 17, there was no method enabling the receiver to report phase differences between signals received by the receiver. Instead, for n-port CSI-RS (n>1), only feedback information indicating phase differences based on 90° granularity between CSI-RS ports existed.

[0103] Meanwhile, while version 18 has been discussing schemes for designing codebooks for CJT, it hasn't yet considered schemes that directly feed back the phase difference between signals received at the receiver. Instead, the focus has been on designing precoding matrices that maximize performance while taking into account the phase difference between signals received at the receiver.

[0104] Various schemes can be considered as methods for feeding back the phase difference between signals received by the receiver in a CJT, but if codebook-based feedback schemes are considered (i.e., if the quantized phase difference is fed back), there may be many limitations. References will now be made to... Figure 6 Describe one of the limitations.

[0105] Figure 6 An example is shown according to an embodiment of the present disclosure for describing a problem that may occur if the phase difference between signals received by the receiver is based on a codebook feedback.

[0106] Reference Figure 6 This illustrates an example of the quantization error that can occur if the phase difference is quantized and represented using two bits. Figure 6 The complex plane is shown, with its x-axis corresponding to the real axis and its y-axis corresponding to the imaginary axis. The phase difference between the received signals, expressed as a quantized value using two bits, corresponds to 0 (0, rad) 610, j (π / 2, rad) 615, -1 (π, rad) 620, and -j (3π / 2, rad) 625 on the complex plane. The phase difference between the received signals measured by the UE can be represented as follows: Figure 6 As shown in 630. During codebook-based phase difference feedback, the receiver must report -j(3π / 2, rad)625, which is closest to the phase difference value 630, and thus quantization errors may occur. To reduce this quantization error, it is necessary to represent the phase difference between the received signals as a quantized value using a larger number of bits (more than two bits). However, using a larger number of bits for feedback may increase the overhead for feedback. Therefore, refer to... Figure 6 There may be a trade-off between the feedback overhead used to feed back the phase difference and the quantization error.

[0107] Next, when the phase difference between signals received by the receiver is fed back based on the codebook, the phase difference in each PRB, which is the measurement target used for feedback, may be non-uniform. More specifically, if a codebook-based feedback method is used, the phase difference value between signals received by the receiver can be applied to all PRBs (wideband reporting method), and the phase difference value between received signals can be applied to a predetermined number of PRBs in each group (subband reporting method). The wideband reporting method and the subband reporting method may each have the following limitations:

[0108] (1) In the case of broadband reporting, the phase difference value that is applied to the received signals of all PRBs may not be an appropriate value in the case of a particular PRB.

[0109] (2) In the case of subband reporting, a separate phase difference value is fed back for each subband, which may increase the overall feedback overhead. Furthermore, the receiver can continuously feed back the phase difference values ​​calculated for each subband, instead of feeding them all back at once. Therefore, a time difference occurs between the time point when the phase difference value for a specific subband is reported and the time point when the corresponding phase difference value is calculated. As a result, the data may be inappropriate (outdated reporting) at the time the corresponding phase difference value is reported.

[0110] This disclosure describes a feedback scheme based on a probe reference signal (SRS) transmitted by the receiver regarding the phase difference between signals received by the receiver (UE), thereby overcoming the limitations of codebook-based feedback schemes regarding the phase difference between signals received by the receiver. More specifically, according to various embodiments of the scheme described in this disclosure, two or more TRPs in a CJT can estimate the phase difference between signals received by the receiver (UE) from two or more TRPs at the resource block (RB) level using the SRS transmitted by the receiver (UE).

[0111] For various embodiments of the schemes described in this disclosure, the following assumptions may be made in advance.

[0112] (1) Coherence time can be guaranteed for 2-3 consecutive symbols in the time domain. That is, it can be assumed that the channel for the nth symbol and the channel for the (n+1)th symbol have the same value. According to the embodiment, it can be understood that if 2-3 consecutive symbols in the time domain are related to the operation of the TRP / receiver to compensate for the phase difference between the received signals via SRS, then coherence time between 2-3 consecutive symbols in the time domain is guaranteed. This can be expressed by the equation This indicates that the index n can be a symbol index that is valid only in a specific time slot. Alternatively, in the case that two different time slots are adjacent to each other, the above equation... It can also be true. When the above equation holds true between two adjacent different time slots, it can only hold true between the last symbol of the first (previous) time slot and the first symbol of the second (second of the two time slots).

[0113] (2) The UE can apply phase shift at the PRB level and then send SRS. The application of phase shift will be described in more detail below with reference to the accompanying drawings.

[0114] In this disclosure, for ease of description, a system model comprising two TRPs and a UE capable of DL / UL transmission / reception from the two TRPs will be described below. The UE can measure the phase of downlink signals received from the two TRPs and can calculate the difference between the individual phases. However, the above system model is for ease of description only, and the scheme proposed in this disclosure can obviously be applied to a system model comprising at least two TRPs and a UE capable of transmitting / receiving signals with at least two TRPs, measuring the phase of downlink signals received from at least two TRPs, and calculating the difference between the individual phases. The operating scheme in a system comprising two or more TRPs and a UE will be described in more detail below.

[0115] The following text will refer to Figure 7 and Figure 8 Describes a scheme for the phase difference between signals received by the UE (receiver) based on SRS feedback.

[0116] Figure 7 An example of a scheme for feedback of phase difference between signals received by a UE, according to embodiments of the present disclosure, is shown. More specifically, Figure 7 This involves implementing a scheme for feedback of the phase difference between signals received by the UE in a system comprising two TRPs and a UE.

[0117] refer to Figure 7 (Operation 1) UE 710 may have 2-port CSI-RS assigned to it by TRP 1 720 or TRP 2 725, and each 1-port CSI-RS can be virtualized and sent to UE 710 from TRP 1 720 and TRP 2 725 respectively (701). The allocation of 2-port CSI-RS to UE 710 can be performed by either TRP 1 720 or TRP 2 725, and higher-layer signaling or dynamic signaling can be used for 2-port CSI-RS allocation. From the UE's perspective, UE 710 has 2-port CSI-RS assigned to it (logically), but may not know which CSI-RS was sent from which TRP. That is, the operation of UE 710 receiving CSI-RS from each of TRP 1 720 and TRP 2 725 can be understood as a UE-transparent operation.

[0118] Return to reference Figure 7(Operation 2) If UE 710 has the capability to measure phase with respect to the real channel (or quasi-real channel), then UE 710 can measure the phase of the CSI-RS received from TRP 1 720 and TRP 2 725 respectively via the received 2-port CSI-RS. The phase of the CSI-RS measured by UE 710 relative to the 1-port CSI-RS received from TRP 1 720 can be... Furthermore, the phase of the CSI-RS measured by UE 710 relative to the port 1 CSI-RS received from TRP 2 725 can be... In the following text, reference will be made to... Figure 8 Additional operations of the scheme disclosed herein for receiving signals based on the phase difference between SRS feedback signals are described.

[0119] Figure 8 An example of a scheme for feedback of phase difference between signals received by a UE, according to embodiments of the present disclosure, is shown. More specifically, Figure 8 This involves implementing a scheme for feedback of the phase difference between signals received by the UE in a system comprising two TRPs and a UE.

[0120] refer to Figure 8 (Operation 3) UE 810 can calculate the phase difference between the phase values ​​measured from the 1-port CSI-RS received from TRP 1 820 and TRP 2 825, respectively, based on the phase values ​​received from TRP 1 820 and TRP 2 825, respectively. In the case of (Operation 3), depending on whether the UE can perform a reference... Figure 7 As described in (Operation 2), the UE can execute different schemes for calculating the phase difference between phase values ​​measured from 1-port CSI-RS received from TRP 1 820 and TRP 2 825, respectively.

[0121] First, if UE 810 can execute Figure 7 In (Operation 2), the UE can calculate the phase difference between the phase values ​​measured by the Port 1 CSI-RS received from TRP 1 820 and TRP 2 825 for each RB. As a result of the calculation, the phase difference between the received signals, calculated by the UE from the phase values ​​measured by the Port 1 CSI-RS received from TRP 1 820 and TRP 2 825, can be... .

[0122] Next, if UE 810 cannot execute Figure 7 In (Operation 2), the UE can calculate the phase difference with respect to each RB by the difference between signals measured with reference to any reference phase, and this can be expressed as In other words, it is obvious that despite differences in the detailed calculation process, the same phase difference value is calculated, regardless of whether the UE 810 can execute. Figure 7 (Operation 2) in the middle.

[0123] refer to Figure 8 (Operation 4) UE 810 may apply a phase shift based on the phase values ​​of the CSI-RS measurements received from TRP 1 and TRP 2 respectively, as measured in (Operation 2), such that on two adjacent different symbols, SRS is sent to TRP 1 820 at the first (preceding) symbol of the two adjacent different symbols (801), and SRS is sent to TRP 1 820 at the second (following) symbol of the two adjacent different symbols (803). Although for ease of description it is assumed that the UE sends SRS to TRP 1 820, the UE may send SRS to either TRP 1 820 or TRP 2 825.

[0124] In this regard, this disclosure defines two phase shift schemes for use with two different SRSs transmitted on two adjacent different symbols.

[0125] First, in two phase shift schemes applied to two different SRSs transmitted on two adjacent different symbols, the first phase shift scheme can be based on the phase difference information calculated in (Operation 3).

[0126] For reference Figure 8 To describe this in more detail, UE 810 sends an SRS to TRP 1 820 (or TRP 2 825) at the nth symbol of two adjacent different symbols (the nth symbol and the (n+1)th symbol), and may not apply a phase shift (801) to the SRS sent in the nth symbol.

[0127] If TRP 1 820 (or TRP 2 825) has already received the SRS transmitted by UE 810 without applying phase shift, then the signal received by TRP 1 820 (or TRP 2 825) at the nth symbol can be represented by the following formula:

[0128] …Equation 2

[0129] In the above formula, It is a symbol From UE to TRP i of Channel is a symbol SRS signal at the location, It is a symbol Noise at that location.

[0130] Next, UE 810 sends an SRS to TRP 1 820 (or TRP 2 825) at the (n+1)th symbol of two adjacent different symbols (the nth symbol and the (n+1)th symbol), applying a phase shift to the SRS sent at the (n+1)th symbol, and the applied phase shift value can be... The phase difference value is calculated in (Operation 3) (803).

[0131] If TRP 1 820 (or TRP 2 825) has received the SRS sent by UE 810 via phase shifting, the received signal can be represented by the following formula:

[0132] …Equation 3

[0133] In the above formula, It is a symbol ( From UE to TRP i The channel, It is a symbol ( The SRS signal at point ) It is a symbol ( Noise at point (). Additionally, satisfying... Furthermore, the SRS sequence transmitted by the UE at the nth symbol and the SRS sequence transmitted by the UE at the (n+1)th symbol can be the same.

[0134] Subsequently, upon receiving the SRS from UE 810, the TRP (TRP 1 820 or TRP 2 825) can derive the phase difference calculated by the UE from the SRS received at the nth and (n+1)th symbols using the following equation:

[0135]

[0136] In other words, upon receiving the SRS from UE 810, the TRP (TRP 1 820 or TRP 2 825) can retrieve the signal received from UE 810 at the (n+1)th symbol. Divide by the signal received at the nth symbol This leads to the phase difference calculated by the UE. In this regard, the premise of this disclosure can be applied: if 2-3 consecutive symbols in the time domain are related to the operation of the TRP / UE compensating for the phase difference between the received signals via SRS, then the coherence time between 2-3 consecutive symbols in the time domain can be guaranteed. That is, the TRP (TRP 1 820 or TRP 2 825) will receive the signal from UE 810 at the (n+1)th symbol. Divided by the signal received at the nth symbol During the process, It can be calculated as with The same value, and can be based on the above premises Calculated as with The same value. Furthermore, because it satisfies... = (The SRS sequence transmitted by the UE at symbol n is the same as the SRS sequence transmitted by the UE at symbol (n+1), therefore the TRP (TRP 1 820 or TRP 2 825) can be obtained by transmitting the signal received from UE 810 at symbol (n+1). Divide by the signal received at the nth symbol This allows us to obtain the phase difference calculated by the UE.

[0137] Next, the phase shift values ​​based on the CSI-RS measurements received from TRP 1 and TRP 2, respectively, can be used for phase shifting. The CSI-RS measurements are based on the second (Operation 2) of two phase shift schemes applied to two different SRS transmitted on two adjacent symbols. If the second phase shift scheme is followed, the phase difference between the received signals is not used, and therefore the process corresponding to (Operation 3) described above can be omitted.

[0138] More specifically, UE 810 sends SRS to TRP 1 820 (or TRP 2 825) at the nth symbol of two adjacent different symbols (the nth symbol and the (n+1)th symbol), and can use the phase value measured by CSI-RS received from TRP 1 820. The phase shift is applied to the SRS (801) transmitted at the nth symbol.

[0139] If TRP 1 820 (or TRP 2 825) has already received the SRS transmitted by UE 810 using a phase shift, that phase shift uses the phase value measured according to the CSI-RS received from TRP 1 820. The signal received by TRP 1820 (or TRP 2825) at the nth symbol can be represented by the following formula:

[0140] …Equation 5

[0141] In the above formula, It is a symbol From UE to TRP i of Channel is a symbol The SRS signal at the location, and It is a symbol Noise at that location.

[0142] Next, UE 810 sends SRS to TRP 1 820 (or TRP 2 825) at the (n+1)th symbol of two adjacent different symbols (the nth symbol and the (n+1)th symbol), and can use the phase value measured by CSI-RS received from TRP 2 825. The phase shift is applied to the SRS (803) sent at the (n+1)th symbol.

[0143] If the TRP 1 820 (or TRP 2 825) has been used by the application based on the phase value measured according to the CSI-RS received from the TRP 2 825 If the phase shift is used to receive the SRS transmitted by UE 810, then the signal received by TRP 1 820 (or TRP 2 825) at the nth symbol can be represented by the following equation:

[0144] …Equation 6

[0145] In the above formula, It is a symbol ( From UE to TR P's channel, It is a symbol ( The SRS signal at point ) and It is a symbol ( Noise at point (). Additionally, satisfying... Furthermore, the SRS sequence transmitted by the UE at the nth symbol and the SRS sequence transmitted by the UE at the (n+1)th symbol can be the same.

[0146] Subsequently, upon receiving the SRS from UE 810, the TRP (TRP 1 820 or TRP 2 825) can derive the phase difference from the SRS received at the nth and (n+1)th symbols using the following formula:

[0147]

[0148] In other words, upon receiving the SRS from UE 810, the TRP (TRP 1 820 or TRP 2 825) can retrieve the signal received from UE 810 at the (n+1)th symbol. Divide by the signal received at the nth symbol This leads to the derivation of the phase difference. In this regard, the premise of this disclosure can be applied: if 2-3 consecutive symbols in the time domain are related to the operation of the TRP / UE compensating for the phase difference between the received signals via SRS, then the coherence time between 2-3 consecutive symbols in the time domain can be guaranteed. That is, the signal received by the TRP (TRP 1 820 or TRP 2 825) from the UE 810 at the (n+1)th symbol... Divided by the signal received at the nth symbol During the process, It can be calculated as with The same value, and It can be calculated as based on the above premises. The same value. Furthermore, because it satisfies... = (The SRS sequence transmitted by the UE at symbol n is the same as the SRS sequence transmitted by the UE at symbol (n+1), therefore the TRP (TRP 1 820 or TRP 2 825) can be obtained by transmitting the signal received from UE 810 at symbol (n+1). Divide by the signal received at the nth symbol This allows us to obtain the phase difference calculated by the UE.

[0149] Hereinafter, methods for allocating CSI-RS resources and SRS resources according to various embodiments of the present disclosure will be described. That is, the various embodiments of the present disclosure described below may involve CSI-RS resource allocation and SRS transmission resource allocation for UE feedback to compensate for phase differences between signals received by the UE from different TRPs.

[0150] First, refer to Figure 9 Describe CSI-RS resource allocation.

[0151] Figure 9 An example of CSI-RS resource allocation according to an embodiment of this disclosure is shown. More specifically, Figure 9 An example of operation in a system comprising two TRPs and a UE is shown.

[0152] refer to Figure 9 This illustrates an example of a 2-port CSI-RS assigned to a UE by one of two TRPs. Each 1-port CSI-RS can be virtualized and then sent to the UE separately from both TRPs.

[0153] If the UE has the capability to measure the phase of a real (or near-real) channel, the UE can measure the phase of CSI-RS 910 and 920 received from TRP 1 and TRP 2 respectively (901) using the received 2-port CSI-RS. As used herein, the real channel can refer to the actual channel, which is not the channel estimated by the UE, or a channel close to the actual channel. The phase of the CSI-RS measured by the UE for 1-port CSI-RS 910 received from one of the two TRPs can be... The phase of the CSI-RS measured for port 1 CSI-RS 920 received by the UE from the other of the two TRPs can be If the UE is configured to operate based on a phase-difference-based phase-shifting scheme, which is the first of two phase-shifting schemes defined in this disclosure, then the UE can operate based on... and Value Calculation A phase shifting scheme for the phase difference between received signals.

[0154] Next, we will refer to Figure 10 Describe the allocation of SRS transmission resources.

[0155] Figure 10 An example of SRS transport resource allocation according to embodiments of the present disclosure is shown. More specifically, Figure 10 An example of operation in a system including two TRPs and a UE is shown, as well as the operation of the first scheme (phase shift scheme based on phase difference information) of two phase shift schemes applied as described above to two different SRSs transmitted on two adjacent different symbols.

[0156] refer to Figure 10 SRS transport resources can be allocated / mapped to specific REs (RE indices 0, 2, 4, 6, and 10) on two different symbols of adjacent time slots, with symbol indices 12 and 13. Figure 10 In this case, the UE sends an SRS to the TRP, which performs phase calibration at the symbol with symbol index 12 in two adjacent different symbols (the symbol with symbol index 12 and the symbol with symbol index 13), and may not apply a phase shift to the SRS sent at the symbol with symbol index 12 (1001). Next, the UE sends an SRS to the TRP that performed the phase calibration at the symbol with symbol index 13 in two adjacent different symbols (the symbol with symbol index 12 and the symbol with symbol index 13), applies a phase shift to the SRS sent at the symbol with symbol index 13, and the applied phase shift value can be the phase difference calculated by the UE. (1003). The phase shift value applied to symbol index 13 has the same value in all resources in the RB used to transmit SRS, and the same phase shift value can be applied to a single RB or to a group of multiple RBs.

[0157] For example, Figure 10 An example of an SRS transmission using a single RB is shown. However, if an SRS transmission using multiple RBs is allocated, and if the configuration is such that the same phase shift value is applied to each individual RB, then the phase shift can be calculated separately for each RB. The value is applied to each RB.

[0158] Alternatively, if an SRS transmission using multiple RBs is allocated, and if the configuration is made such that the same phase shift value is applied to each group of RBs whose number is the same as the number of RBs allocated for the SRS transmission, then the phase shift value is calculated separately for each RB. The common phase difference value derived from the specific calculation result of the value ( This can be applied equally to multiple RBs. Common phase difference ( () can be configured to be calculated separately in each RB. The average value, or configured as a representative phase difference value derived from a specific RB (which is predefined or configured by higher-layer signaling, etc.) among a plurality of RBs, or configured as the average value of representative phase differences derived from at least one specific RB (which is predefined or configured by higher-layer signaling, etc.) among a plurality of RBs.

[0159] Alternatively, if an SRS transmission using multiple RBs is allocated, and if the number of RBs configured to apply the same phase shift value to each group of sub-RBs (e.g., two) is less than the number of RBs allocated for the SRS transmission (e.g., four), then the same scheme can be applied to each group of sub-RBs as in the case where the same phase shift value is applied to each group of RBs, in the same number as the number of RBs allocated for the SRS transmission. More specifically, assuming four RBs (RB#0, RB#1, RB#2, RB#3) constitute two sub-RBs, and each of the two sub-RBs is configured such that (sub-RB#0 includes RB#0 and RB#1, and sub-RB#1 includes RB#2 and RB#3), then the values ​​calculated separately for each of the two RBs contained in sub-RB#0 are... The common phase difference value obtained from specific calculation results ( The same applies to the two RBs contained in sub-RB#0. Common phase difference ( () can be configured to be calculated separately in each RB. The average value, or configured as a representative phase difference value derived from a specific RB (predefined or configured by higher-layer signaling, etc.) among a plurality of RBs, or configured as the average value of representative phase differences derived from at least one specific RB (predefined or configured by higher-layer signaling, etc.) among a plurality of RBs.

[0160] Furthermore, as a value calculated separately for each of the two RBs contained in subRB#1 The common phase difference value obtained from specific calculation results ( This can also be applied to the two RBs contained in sub-RB#1. Common phase difference ( () can be configured to be calculated separately in each RB. The average value, or configured as a representative phase difference value derived from a specific RB (predefined or configured by higher-layer signaling, etc.) among a plurality of RBs, or configured as the average value of representative phase differences derived from at least one specific RB (predefined or configured by higher-layer signaling, etc.) among a plurality of RBs.

[0161] Obviously, in Figure 10 In the example, the symbol index of the SRS transport resource and the location of the RE in the RB are merely examples for description and can be compared with... Figure 10 Examples of various ways to allocate SRS transport resources.

[0162] Subsequently, upon receiving the SRS from the UE, the TRP performing phase calibration can derive the phase difference (1005) calculated by the UE from the SRS received at the symbol index 12 and the symbol index 13.

[0163] refer to Figure 10 The described operation can be similarly applied to the two phase shift schemes of this disclosure, wherein the phase shift is based on the phase values ​​measured by CSI-RS received from each of the two TRPs. More specifically, there may be differences in UE operation because... Figure 10 In case 1001, the phase value can be measured using CSI-RS received from one of the two TRPs. The phase shift is applied to the SRS transmitted at the symbol with symbol index 12, and in case 1003, the UE operation causes the phase value measured by CSI-RS received from one of the two TRPs to be used. The phase shift is applied to the SRS transmitted at the symbol with symbol index 12.

[0164] In the following text, reference will be made to Figures 11 to 13 Describe a scheme for feeding back the phase difference between signals received by the UE (receiver) in a system model comprising two or more TRPs and UEs.

[0165] Figure 11 An example of a scheme for feedback of phase difference between signals received by a UE, according to embodiments of the present disclosure, is shown. More specifically, Figure 11 This involves a scheme for implementing feedback on the phase difference between signals received by the UE in a system comprising four TRPs and a UE.

[0166] Reference Figure 11 To maximize performance gain through CJT, when the UE receives signals from four TRPs respectively, it may be necessary that there is no phase difference between the signals received from the four TRPs. Therefore, at the time of UE reception, the phase of each signal received from the three TRPs that perform phase calibration needs to be equal to the phase of the signal received from that specific TRP at the time of UE reception (the phases need to be synchronized). That is, if the phase of the signal received from a specific TRP at the time of UE reception is π / 2 (rad), then the phase of each of the signals received from the other three TRPs at the time of UE reception may need to satisfy π / 2 (rad). Hereinafter, for ease of description, the specific TRP that needs to be synchronized with the phase of the signal received from the other TRPs at the time of UE reception will be referred to as the reference TRP. Figure 11 In this case, TRP 11110 can be understood as a reference TRP.

[0167] Although Figure 11 Although not shown in the diagram, the UE has 4-port CSI-RS assigned to it by one of four TRPs: 1110, 1120, 1130, and 1140. Each port 1 CSI-RS can be virtualized and sent to the UE 1150 from TRP 1 1110, TRP 2 1120, TRP 3 1130, and TRP 4 1140 respectively. The 4-port CSI-RS can be assigned to the UE 1150 using higher-layer signaling or dynamic signaling. From the UE's perspective, the UE 1150 has the 4-port CSI-RS assigned to it (logically), but may not know which CSI-RS was sent from which TRP. That is, the operation of the UE 1150 receiving port 1 CSI-RS from TRP 11110, TRP 2 1120, TRP 3 1130, and TRP 4 1140 respectively can be a UE-transparent operation.

[0168] Despite Figure 11Not shown, but if UE 1150 has the capability to measure the phase of the real channel (or quasi-real channel), then UE 1150 can measure the phase of the CSI-RS received from TRP 11110, TRP 2 1120, TRP 3 1130, and TRP 4 1140 respectively via the received 4-port CSI-RS. The phase of the CSI-RS received by UE 1150 from TRP 11110 for the 1-port CSI-RS measurement can be... Furthermore, the phase of the CSI-RS measured for port 1 CSI-RS received by UE 1150 from TRP 21120 can be... Furthermore, the phase of the CSI-RS measured for port 1 CSI-RS received by UE 1150 from TRP 31130 can be... Furthermore, the phase of the CSI-RS measured for port 1 CSI-RS received by UE 1150 from TRP 41140 can be... .

[0169] Despite Figure 11 Not shown, but if UE 1150 has the UE capability that allows it to measure the phase with respect to the real channel (or quasi-real channel), then UE 1150 can, with respect to each RB, (1) calculate the phase difference between the phase values ​​measured by the 1-port CSI-RS received by the UE from TRP 1 1110 (reference TRP) and TRP 2 1120 respectively. (2) Calculate the phase difference between the phase values ​​measured by the 1-port CSI-RS received by the UE from TRP 1 1110 (reference TRP) and TRP 3 1130 respectively. (3) Calculate the phase difference between the phase values ​​measured by 1-port CSI-RS received by the UE from TRP1 1110 (reference TRP) and TRP4 1140 respectively. In other words, the above calculations (1) to (3) are performed in one RB, and the above calculations (1) to (3) can be performed for each of at least one RB associated with the operation of compensating for the phase difference between the signals received by the UE.

[0170] Despite Figure 11Not shown, but if UE 1150 has the capability to measure the phase with respect to the real channel (or quasi-real channel), then UE 1150 can calculate the phase difference with respect to the difference of the signal measured by reference to any reference phase for each RB. Additionally, the UE can (1) calculate the phase difference between the phase values ​​measured by the 1-port CSI-RS received by the UE from TRP 1 1110 (reference TRP) and TRP 2 1120 respectively. (2) Calculate the phase difference between the phase values ​​measured by the 1-port CSI-RS received by the UE from TRP 1 1110 (reference TRP) and TRP 3 1130 respectively. (3) Calculate the phase difference between the phase values ​​measured by the 1-port CSI-RS received by the UE from TRP 1 1110 (reference TRP) and TRP 4 1140 respectively. In other words, the above calculations (1) to (3) are performed in one RB, and the above calculations (1) to (3) can be performed for each of at least one RB associated with the operation of compensating for the phase difference between the signals received by the UE. It is understood that, despite the differences in the detailed calculation process, the same phase difference value is calculated regardless of whether the UE is able to measure the phase with respect to the real channel (or quasi-real channel).

[0171] Now we will refer to the perspective of resource allocation. Figure 12 The description describes how UE 1150 receives port 1 CSI-RS from TRP 1 1110, TRP 2 1120, TRP 3 1130 and TRP 4 1140 respectively, and measures the phase of the received CSI-RS. , , , (The operation of )

[0172] Figure 12 An example of CSI-RS resource allocation according to an embodiment of this disclosure is shown. More specifically, Figure 12 An example of operation in a system including four TRPs and UEs is shown.

[0173] Reference Figure 12 This example illustrates a 4-port CSI-RS resource allocated to a UE from one of four TRPs. Each 1-port CSI-RS can be virtualized and sent to the UE separately from the four TRPs.

[0174] If the UE has the capability to measure the phase of the real channel (or quasi-real channel), then the UE can measure the phase of CSI-RS 1210, 1220, 1230, and 1240 received from TRP 1 (reference TRP), TRP 2, TRP 3, and TRP 4, respectively, via the received 4-port CSI-RS. The UE can receive 1-port CSI-RS from TRP 1 1210, TRP 2 1220, TRP 3 1230, and TRP 4 1240, respectively, and can represent the phase of the CSI-RS measured with respect to the received CSI-RS as follows: If the UE is configured to operate based on a phase-difference-based phase-shifting scheme, which is the first of two phase-shifting schemes defined in this disclosure, then the UE can operate based on... To calculate the phase difference between the received signals. , and .

[0175] Return to reference Figure 11 The UE 1150 can base its measurement on the phase of the CSI-RS received from the 1-port CSI-RS received from TRP 1 1110, TRP 2 1120, TRP 3 1130, and TRP 4 1140, respectively. , , , Apply a phase shift such that, except for TRP 1 1110 (reference TRP), the first (preceding) symbol in two adjacent different symbols sends SRS (1101) to TRP 2 1120, TRP 3 1130 and TRP 4 1140 respectively, and except for TRP 1 1110 (reference TRP), the second (following) symbol in two adjacent different symbols sends SRS (1103) to TRP 2 1120, TRP 3 1130 and TRP 4 1140 respectively.

[0176] if Figure 11 If the phase shift operation follows the first scheme of the two phase shift schemes defined in this disclosure, which uses phase difference information, then UE 1150 sends SRS to TRP 2 1120, TRP 3 1130 and TRP 4 1140 at the nth symbol of two adjacent different symbols (the nth symbol and the (n+1)th symbol), and may not apply phase shift (1101) to the SRS sent in the nth symbol.

[0177] If TRP 2 1120, TRP 3 1130, and TRP 4 1140 have received the SRS transmitted by UE 1150 without applying phase shift, then the signal (SRS) received by TRP 2 1120, TRP 3 1130, and TRP 4 1140 at the nth symbol can be represented by the following formula:

[0178] …Equation 8

[0179] In the above formula, It is a symbol From UE to TRP i The channel, It is a symbol SRS signal at the location, It is a symbol Noise at that location.

[0180] Next, UE 1150 transmits SRS to TRP 2 1120, TRP 3 1130, and TRP 4 1140 at the (n+1)th symbol in two adjacent different symbols (the nth symbol and the (n+1)th symbol), applying a phase shift to the SRS transmitted at the (n+1)th symbol, and the applied phase shift value can be... It is the phase difference value (803) calculated by the UE for TRP 21120, TRP 3 1130 and TRP 4 1140 respectively.

[0181] If TRP 1 (or TRP 2) has received the SRS sent by the UE through the application of phase shift, the received signal can be represented by the following formula:

[0182] …Equation 9

[0183] In the above formula, This is for reference TRP and TRP. i Calculated phase difference, It is a symbol ( From UE to TRP i The channel, It is a symbol ( The SRS signal at point ) It is a symbol ( Noise at point (). Additionally, satisfying... Furthermore, the SRS sequence transmitted by the UE at the nth symbol and the SRS sequence transmitted by the UE at the (n+1)th symbol can be the same.

[0184] Subsequently, upon receiving the SRS from UE 1150 at the nth and (n+1)th symbols, TRP 2 1120, TRP 3 1130, and TRP 4 1140 can derive the phase difference calculated by the UE from the SRS received at the nth and (n+1)th symbols using the following equation:

[0185]

[0186] In other words, upon receiving the SRS from UE 1150, each of TRP 2 1120, TRP 3 1130, and TRP 4 1140 can retrieve the signal received from UE 1150 at the (n+1)th symbol. Divide by the signal received at the nth symbol This leads to the phase difference calculated by the UE. In this regard, the premise of this disclosure can be applied, namely, if 2-3 consecutive symbols in the time domain are related to the operation of the TRP / UE compensating for the phase difference between the received signals via SRS, then the coherence time between 2-3 consecutive symbols in the time domain can be guaranteed. That is, the signal received by UE 160 at the (n+1)th symbol in each of TRP 2 1120, TRP 3 1130, and TRP 4 1140... Divided by the signal received at the nth symbol During the process, It can be calculated as with The same value, and It can be calculated as based on the above premises. The same value. Furthermore, because it satisfies... = (The SRS sequence transmitted by the UE at symbol n is the same as the SRS sequence transmitted by the UE at symbol (n+1), therefore each of TRP 2 1120, TRP 3 1130 and TRP 4 1140 can be achieved by transmitting the signal received from UE 1150 at symbol (n+1). Divide by the signal received at the nth symbol This allows us to obtain the phase difference calculated by the UE.

[0187] Next, if Figure 11The phase shift operation follows the second of two phase shift schemes defined in this disclosure, wherein the phase values ​​measured by CSI-RS received from the TRP are directly used for phase shifting. In this case, UE 1150 sends SRS to TRP 2 1120, TRP 3 1130, and TRP 4 1140 at the nth symbol of two adjacent different symbols (the nth symbol and the (n+1)th symbol), respectively, and can use the phase values ​​measured by CSI-RS received from TRP 1 1110 (reference TRP). The phase shift is applied to the SRS transmitted at the nth symbol (1101).

[0188] If each of TRP 2 1120, TRP 3 1130, and TRP 4 1140 has been used with the phase value measured by CSI-RS according to the data received from TRP 1 1110 (reference TRP), then... If the phase shift is used to receive the SRS transmitted by UE 1150, then the signal (SRS) received at the nth symbol by each of TRP 2 1120, TRP 3 1130 and TRP 4 1140 can be expressed by the following formula:

[0189] …Equation 11

[0190] In the above formula, It is a symbol From UE to TRP i The channel, It is a symbol SRS signal at the location, It is a symbol Noise at that location.

[0191] Next, UE 1150 transmits SRS to each of TRP 2 1120, TRP 3 1130, and TRP 4 1140 at the (n+1)th symbol in two adjacent different symbols (the nth symbol and the (n+1)th symbol), and can apply a phase shift to the SRS transmitted at the (n+1)th symbol, such that... and Used respectively according to TRP (1103) which should receive the phase value SRS measured by CSI-RS from TRP 1 (reference TRP).

[0192] If each of TRP 2 1120, TRP 3 1130, and TRP 4 1140 has received the SRS transmitted by applying phase shift, then and The phase values ​​of the CSI-RS measured by the TRP that should receive the SRS are respectively used as the phase values ​​of the SRS measured by the TRP that the UE 1150 has received from each of the TRPs 1120, 1130, and 1140. The signal received at the (n+1)th symbol by each of TRP 2 1120, TRP 3 1130, and TRP 4 1140 can be represented by the following formula:

[0193] …Equation 12

[0194] In the above formula, It is UE relative to TRP i Transmitted CSI-RS phase measured by port 1 CSI-RS, TRP i Phase calibration is performed using the reference TRP. It is a symbol ( From UE to TRP i The channel, ) is a symbol ( The SRS signal at point ) It is a symbol ( Noise at point (). Additionally, satisfying... )= Furthermore, the SRS sequence transmitted by the UE at the nth symbol and the SRS sequence transmitted at the (n+1)th symbol can be the same.

[0195] Subsequently, when receiving the SRS from UE 1150 at the nth and (n+1)th symbols, TRP 2 1120, TRP 3 1130, and TRP 4 1140 can derive the phase difference between the signals received by the UE (i.e., between the signal received from the reference TRP and each of the remaining TRPs) from the SRS received at the nth and (n+1)th symbols using the following equation:

[0196]

[0197] In other words, upon receiving the SRS from UE 1150, each of TRP 2 1120, TRP 3 1130, and TRP 4 1140 can retrieve the signal received from UE 1150 at the (n+1)th symbol. Divide by the signal received at the nth symbol This leads to the phase difference calculated by the UE. In this regard, the premise of this disclosure can be applied, namely, if 2-3 consecutive symbols in the time domain are related to the operation of the TRP / UE compensating for the phase difference between the received signals via SRS, then the coherence time between 2-3 consecutive symbols in the time domain can be guaranteed. That is, the signal received by UE 1150 at the (n+1)th symbol in each of TRP 2 1120, TRP 3 1130, and TRP 4 1140... Divided by the signal received at the nth symbol During the process, It can be calculated as with The same value, and It can be calculated as based on the above premises. The same value. Furthermore, because it satisfies... (The SRS sequence transmitted by the UE at the nth symbol is the same as the SRS sequence transmitted by the UE at the (n+1)th symbol), therefore each of TRP 2 1120, TRP 3 1130 and TRP 4 1140 can be achieved by transmitting the signal received from UE 1150 at the (n+1)th symbol. Divide by the signal received at the nth symbol This allows us to obtain the phase difference calculated by the UE.

[0198] Now refer to Figure 13 describe Figure 11 UE-related SRS transmission resource allocation.

[0199] Figure 13 An example of SRS transport resource allocation according to embodiments of the present disclosure is shown. More specifically, Figure 13 An example of operation in a system including four TRPs and UEs is shown, as well as the operation of the first scheme (phase shift scheme based on phase difference information) of two phase shift schemes applied as described above to two different SRSs transmitted on two adjacent different symbols.

[0200] refer to Figure 13The SRS transmission resources of TRP 2 1120, TRP 3 1130 and TRP 4 1140, which perform phase calibration, can be allocated / mapped to specific REs (RE indices 0, 2, 4, 6 and 10) in RBs on two different symbols (symbol indices 12 and 13) that are adjacent to each other in the time slot. More specifically, the RE positions for SRS transmission resources used for phase calibration reference between TRP 1 1110 and TRP 2 1120 can be assigned to positions 1330 and 1360 in the RB with RE indices 0 and 6, respectively; the RE positions for SRS transmission resources used for phase calibration reference between TRP 1 1110 and TRP 3 1130 can be assigned to positions 1320 and 1350 in the RB with RE indices 2 and 8, respectively; and the RE positions for SRS transmission resources used for phase calibration reference between TRP 1 1110 and TRP 4 1140 can be assigned to positions 1310 and 1340 in the RB with RE indices 4 and 10, respectively. However, Figure 13 The symbol index positions of SRS transmission resources in the diagram, the positions of RE resources in the RB, and the mapping between the positions of RE resources and the TRPs that should receive the SRS are merely examples for description, and it is obvious that... Figure 13 The mapping between the symbol index location of the SRS transmission resource in the RB, the location of the RE resource in the RB, and the location of the RE resource and the TRP that should receive the SRS can be compared with... Figure 13 The configurations shown are different.

[0201] Refer again Figure 13 The UE can send SRS to TRP 2 1120, TRP 3 1130 and TRP 4 1140, which perform phase calibration, at the symbol with symbol index 12 in two adjacent different symbols (the symbol with symbol index 12 and the symbol with symbol index 13), and can choose not to apply phase shift to the SRS sent at the symbol with symbol index 12.

[0202] Next, the UE transmits SRS at symbol index 13 in two adjacent different symbols (symbol with symbol index 12 and symbol with symbol index 13) to TRP 2 1120, TRP 3 1130, and TRP 4 1140, which are performing phase calibration, respectively. The UE applies a phase shift to the SRS transmitted at symbol index 13, and the applied phase shift value can be the phase difference calculated by the UE for each TRP. . This represents the phase difference calculated with respect to the reference TRP and TRP i. The phase shift value applied to symbol index 13 can have the same value in all REs associated with a TRP that assumes receiving the same SRS in the same RB.

[0203] The following describes a method for the TRP to calculate the phase difference for phase calibration with respect to each RB, based on the SRS sent by the UE to the TRP performing phase calibration. Phase calibration can refer to the operation of a particular TRP applying the inter-TRP phase difference value calculated by the SRS received from the UE to the downlink signal, such that the phase of the signal transmitted by it and received by the UE is the same as the phase of the signal transmitted by the reference TRP and received by the UE.

[0204] Figure 14 An example of a method for calculating phase difference according to an embodiment of the present disclosure is shown. Figure 14 This involves performing phase calibration between two TRPs and the UE.

[0205] Reference Figure 14 The UE can send an SRS to the TRP performing phase calibration at symbol n 1410, and can also send an SRS to the TRP performing phase calibration at symbol (n+1) 1420.

[0206] As an example of a method for calculating the phase difference between received signals, the TRP performing phase calibration can calculate the phase difference between the phase of the signal transmitted by the reference TRP and received by the UE and the phase of the signal transmitted by the TRP performing phase calibration and received by the UE, based on the SRS received at symbol n and symbol (n+1), according to the following equation:

[0207] …Equation 14

[0208] In the equation above, the set Configured by the subcarrier index assigned to the SRS. It refers to the collection Subcarriers included The phase difference between sign n and sign (n+1) at point n, and This refers to the sequence of symbols n and (n+1) from the set. The average of the phase differences calculated from all the subcarriers included in the calculation.

[0209] Figure 15 Other examples of methods for calculating phase differences according to embodiments of the present disclosure are shown. Figure 15 This involves performing phase calibration between two TRPs and the UE.

[0210] refer to Figure 15As an example of a method for calculating the phase difference between received signals, assuming that the TRP performing phase calibration receives two or more SRS signals (1510 and 1520) from the UE for phase calibration, the phase difference between the phases of the signals transmitted by the TRP performing phase calibration and received by the UE can be calculated according to the following formula:

[0211] …Equation 15

[0212] In the equation above, With Equation 14 above The same applies, and the set can be configured via the symbol index assigned to the SRS. In other words, if SRS is sent i times at different times using two symbols, Then it can have the value of i.

[0213] As an example of a method for calculating the phase difference between received signals, assuming that the TRP performing phase calibration receives an SRS (1520) for phase calibration from the UE at a specific time point, then when calculating the phase difference value using the SRS received at the specific time point, the phase difference value calculated using the SRS 1510 for phase calibration received before the specific time point can be considered. The operation according to this example can be calculated based on the following equation:

[0214] …Equation 16

[0215] In the equation above, This can be the size of the moving window, and it can be understood as equivalent to the weights applied to the phase difference calculated at a specific point in time when the SRS is received and to the weights applied to the phase difference calculated using SRS received before that specific point in time. That is, assuming the phase difference calculated at the specific point in time when the SRS is received is 10, and the phase difference calculated using SRS received before that specific point in time is 8, and... If the value is 0.5, then the phase difference calculated at a specific time point can be (1-0.5). 8+0.5 10 = 9.

[0216] The following describes a method for performing phase calibration by TRP to calculate the phase difference and then determining whether the calculated phase difference is valid information.

[0217] First, a method for determining whether the phase difference is valid will be described, assuming that the UE transmits at least two SRS for phase calibration in one time slot, or the UE transmits at least two SRS for phase calibration in two adjacent time slots.

[0218] Figure 16 and Figure 17 Examples of methods for determining the validity of a phase difference calculated by a TRP, according to various embodiments of the present disclosure, are shown.

[0219] Reference Figure 16 An example is shown where the UE sends two SRSs (1610 and 1620) for phase calibration twice in one time slot.

[0220] refer to Figure 17 This illustrates an example of two SRSs being sent from the UE for phase calibration in two adjacent time slots.

[0221] exist Figure 16 and Figure 17 In both cases shown, the validity of the calculated phase difference can be determined using the same method. The validity can be determined by whether the absolute values ​​of the phase difference (1610 / 1710) calculated from the first two SRSs transmitted in two separate transmissions and the absolute values ​​of the phase difference (1620 / 1720) calculated from the later two SRSs are less than a specific threshold (i.e., This is used to determine the validity of the phase difference calculated at different time points. Regarding the threshold parameter, the threshold can be... The optimized parameters can be the average phase difference calculated from the SRS transmitted on symbol n and symbol (n+1), and It can be the average phase difference value calculated by the SRS transmitted on symbol m and symbol (m+1).

[0222] Next, a method for determining whether the phase difference is valid will be described, assuming that the SRS used for phase calibration are transmitted from the UE in different time slots that are not adjacent to each other.

[0223] In this method, when determining the validity of the phase difference calculated by SRS transmitted on symbol m and symbol (m+1) in a specific time slot, the phase difference calculated by SRS transmitted on symbol n and symbol (n+1) in a time slot that is not adjacent to the specific time slot but precedes the specific time slot is used, and the moving window size based method described above with reference to Equation 16 is used. The phase difference value can be used to calculate the phase difference by transmitting SRS on symbol n and symbol (n+1) in a time slot prior to a specific time slot.

[0224] Figure 18 An example of a method for determining the validity of a phase difference calculated by a TRP, according to an embodiment of the present disclosure, is shown.

[0225] Reference Figure 18The validity of the phase difference calculated by the SRS transmitted on symbols 12 and 13 in a specific time slot 1820 can be determined by the phase difference calculated based on the moving window size from the SRS transmitted on symbols 12 and 13 in time slot 1810 prior to specific time slot 1820. The absolute value of the value obtained by subtracting the phase difference from the phase difference calculated by the SRS transmitted on symbols 12 and 13 in a specific time slot 1820, and the threshold ( This is determined by comparison. It is calculated based on the moving window size from the SRS transmitted on symbols 12 and 13 in time slot 1810 prior to a specific time slot 1820. If the absolute value of the value obtained by subtracting the phase difference from the phase difference obtained by transmitting the SRS on symbols 12 and 13 in a specific time slot 1820 is less than the threshold, then the phase difference calculated by transmitting the SRS on symbols 12 and 13 can be considered valid.

[0226] The following describes the signaling messages required to perform the feedback method for phase calibration between received signals as disclosed in this disclosure. Such signaling messages are, for example, RRC messages.

[0227] When the parameter SRS-ResourceSet, which indicates the resource set used for SRS transmission, contains a Purpose Information Element (IE) indicating the purpose of the resource set used for SRS transmission, the purpose "calibration" can be added to the resource set used for SRS transmission to indicate its use for phase calibration between signals received by the UE during multiple TRP operations. That is, in addition to the purposes included in the existing Purpose field such as "beam management," "codebook-based," "non-codebook-based transmission," or "antenna switching," the Purpose field can indicate that the corresponding SRS resource set is used for the "calibration" purpose.

[0228] If "calibration" is added to the usage field, the relevant specifications can be changed (underlined) as follows:

[0229] Table 1

[0230]

[0231] Additionally, the calibrationGranularity IE can be added to the parameter SRS-Resource, which indicates the SRS resources associated with the resource set used for SRS transmission, and the calibrationGranularity IE is configured such that, for example, calibrationGranularity={wideband,n1,n2,n4,…}. The calibrationGranularity IE can indicate a value in units of the number of RBs to which the phase shift is applied in the frequency domain when a phase shift is applied to two SRSs transmitted for phase calibration. That is, assuming 8 RBs are configured to transmit SRS on two symbols for phase calibration, and calibrationGranularity=n1 is configured, the same phase shift value for the SRS transmitted on both symbols can be applied to each RB (i.e., a separately calculated phase difference value is applied to each RB). Alternatively, assuming 8 RBs are configured to transmit SRS on two symbols for phase calibration, and calibrationGranularity=n2 is configured, the same phase shift value for the SRS transmitted on both symbols can be applied to every two RBs. Furthermore, assuming 8 RBs are configured to transmit SRS on two symbols for phase calibration, and calibrationGranularity=wideband is configured, then the same phase shift value can be applied to each RB for the SRS transmitted on both symbols. More specifically, the description of applying the same phase shift value to RBs might mean applying the same phase shift value to REs within the RBs for which the same phase shift value is applied.

[0232] Additionally, the calibrationRS IE can be added to the SRS-Resource parameter, which indicates the SRS resources associated with the resource set used for SRS transmission. The calibrationRS IE can also be a parameter indicating the CSI-RS resources associated with SRS transmitted for phase calibration. That is, when the UE transmits SRS on a specific SRS resource by applying a phase shift for phase calibration, information about the CSI-RS resources that the UE needs to receive in order to obtain the value of the phase shift applied to the SRS transmitted on that specific SRS resource can be included in the calibrationRS IE.

[0233] Various types of calibration IEs that can be configured according to various embodiments of this disclosure will now be described.

[0234] First, the calibrationRS IE configuration for the case of two TRPs and UE transmit / receive signals will be described. When the calibrationRS IE indicates a 2-port CSI-RS resource transmitted for phase calibration, it can be assumed that two subcarriers are configured on one symbol to transmit the 2-port CSI-RS resource in one RB, and code division multiplexing (CDM) is not applied between the CSI-RS resources. Then, the 1-port CSI-RS transmitted by TRP 1 (reference TRP) can be assigned to the subcarrier corresponding to RE index 0, and the 1-port CSI-RS transmitted by TRP 2 can be assigned to the subcarrier corresponding to RE index 1. Therefore, the UE can obtain the phase value through the 1-port CSI-RS transmitted on the subcarrier corresponding to RE index 0 of TRP 1. Furthermore, the UE can obtain the phase value via 1-port CSI-RS transmitted on the subcarrier corresponding to RE index 1 of TRP 2. The phase difference between the signals received by the UE relative to TRP 2 and TRP 1 (reference TRP) can be calculated by subtracting the phase of the signal received by the UE relative to TRP 2 from the phase of the signal received by the UE relative to TRP 1.

[0235] Next, the calibration RS IE configuration will be described for the case of n (>2) TRPs and UE transmitting / receiving signals.

[0236] Based on the first calibrationRSIE configuration applicable to the case of n (>2) TRPs and one UE transmit / receive signal, the IE configuration can be configured by extending the same type of calibrationRS IE configuration described above for the case of two TRPs and one UE transmit / receive signal and applying it to the case of n (>2) TRPs and one UE transmit / receive signal. That is, when indicating n-port CSI-RS resources transmitted for phase calibration, it can be assumed that n subcarriers are configured on one symbol to transmit n-port CSI-RS resources in one RB, and code division multiplexing (CDM) is not applied between CSI-RS resources. The 1-port CSI-RS transmitted by the reference TRP among the n TRPs can be assigned to the subcarrier corresponding to the lowest RE index in the RB on one symbol of the time slot where the CSI-RS is transmitted. Assuming that TRP indices (identifiers) with integer values ​​from 2 to n are assigned to the remaining (N-1) TRPs in a predetermined manner, then a 1-port CSI-RS transmitted by each of the (N-1) TRPs can be allocated to the subcarriers corresponding to the RE indices in the RB in ascending order of the given TRP indices. The phase difference between the signal received by the UE relative to the reference TRP and the signal received by each remaining TRP can be calculated by subtracting the phase of the signal received by the UE relative to each remaining TRP from the phase of the signal received by the UE relative to the reference TRP. As an example, when the calibrationRS IE indicates a 4-port CSI-RS to be transmitted for phase calibration, it can be assumed that four subcarriers are configured on one symbol to transmit the 4-port CSI-RS in one RB, and that code division multiplexing (CDM) is not applied between CSI-RS resources. Then, the port 1 CSI-RS transmitted by TRP 1 (reference TRP) can be assigned to the subcarrier corresponding to RE index 0, the port 1 CSI-RS transmitted by TRP 2 can be assigned to the subcarrier corresponding to RE index 1, the port 1 CSI-RS transmitted by TRP 3 can be assigned to the subcarrier corresponding to RE index 2, and the port 1 CSI-RS transmitted by TRP 4 can be assigned to the subcarrier corresponding to RE index 3. Therefore, the UE can obtain the phase value through the port 1 CSI-RS transmitted on the subcarrier corresponding to RE index 0 of TRP 1. The UE can obtain the phase value through 1-port CSI-RS transmitted on the subcarrier corresponding to RE index 1 of TRP 2. The UE can obtain the phase value through 1-port CSI-RS transmitted on the subcarrier corresponding to RE index 1 of TRP 3. Furthermore, the UE can obtain the phase value via 1-port CSI-RS transmitted on the subcarrier corresponding to RE index 1 of TRP 2. The phase difference between TRP1 (reference TRP) and each of TRP2 to TRP4 can be calculated by subtracting the phase of the signal received by the UE relative to each of TRP2 to TRP4 from the phase of the signal received by the UE relative to TRP1.

[0237] According to the second calibrationRS IE configuration applicable to n (>2) TRPs and UE transmit / receive signals, the calibrationRS IE configuration can be configured to indicate CSI-RS resources for calculating the phase shift value corresponding to the SRS transmitted at a specific subcarrier index for each subcarrier index in the RB associated with the SRS transmission.

[0238] More specifically, calibrationRSList can be configured to include a list of calibrationRS, where the nth calibrationRS included in calibrationRSList can indicate the RS used to calculate the phase shift value of the subcarrier to be applied to the nth SRS in the RB.

[0239] As an example, calibrationRSList can be configured in the following format:

[0240] calibrationRSList ::= SEQUENCE (SIZE(1..6)) OF calibrationRS

[0241] In this scenario, a calibrationRSList is configured for each RB, and when SRS resources are configured in a comb n2 type within an RB, the number of subcarriers that can be configured in an RB for transmitting SRS is six. Therefore, the calibrationRSList can be configured to include six calibrationRSs. For example, if the UE is transmitting / receiving signals using seven TRPs, it is necessary to calibrate the phase difference between TRP 1 (reference TRP) and each of the remaining TRPs 2 through 7. If SRS is transmitted in comb n2 type on two consecutive symbols within an RB, the corresponding SRS can be transmitted at six subcarriers. That is, a first SRS for phase calibration between TRP 1 and TRP 2, a second SRS for phase calibration between TRP 1 and TRP 3, a third SRS for phase calibration between TRP 1 and TRP 4, a fourth SRS for phase calibration between TRP 1 and TRP 5, a fifth SRS for phase calibration between TRP 1 and TRP 6, and a sixth SRS for phase calibration between TRP 1 and TRP 7 can be transmitted. In this case, calibrationRSList may include information about a first 2-port CSI-RS resource related to a phase shift applied during a first SRS transmission, a second 2-port CSI-RS resource related to a phase shift applied during a second SRS transmission, a third 2-port CSI-RS resource related to a phase shift applied during a third SRS transmission, a fourth 2-port CSI-RS resource related to a phase shift applied during a fourth SRS transmission, a fifth 2-port CSI-RS resource related to a phase shift applied during a fifth SRS transmission, and a sixth 2-port CSI-RS resource related to a phase shift applied during a sixth SRS transmission.

[0242] Furthermore, according to the third calibrationRSIE configuration applicable to n (>2) TRPs and UE transmit / receive signals, the calibrationRSIE configuration can be configured to configure a mode for applying phase shift to subcarriers in RBs associated with SRS transmission, and indicate the 2-port CSI-RS resources used to calculate the phase difference applied during SRS transmission in the order of the lowest subcarrier index in the configured mode.

[0243] More specifically, calibrationRSList can be configured as a list of calibrationRS, and the nth calibrationRS can indicate a CSI-RS resource used to calculate the phase shift value of the subcarrier group with the nth lowest subcarrier group index among all subcarrier groups that include subcarriers applying the same phase shift in the phase shift mode pre-configured in the RB.

[0244] Now refer to Figure 19 The third type of calibrationRS IE configuration is described in more detail for cases where there are n (>2) TRPs and UEs transmitting / receiving signals.

[0245] Figure 19 An example of a calibrationRSList configuration according to an embodiment of this disclosure is shown. More specifically, Figure 19 The diagram illustrates a scenario with four TRPs and one UE transmitting / receiving signals, and SRS resource allocation is configured in a comb n2 mode (i.e., SRS per symbol uses RE density = 1 / 2).

[0246] Reference Figure 19 The phase shift pattern can be configured such that a first SRS for phase calibration between TRP 1 (reference TRP) and TRP 2 is transmitted at subcarriers 1960 and 1930 corresponding to RE indices 0 and 6, while applying the same phase shift; a second SRS for phase calibration between TRP 1 (reference TRP) and TRP 3 is transmitted at subcarriers 1950 and 1920 corresponding to RE indices 2 and 8, while applying the same phase shift; and a third SRS for phase calibration between TRP 1 (reference TRP) and TRP 4 is transmitted at subcarriers 1940 and 1910 corresponding to RE indices 4 and 10, while applying the same phase shift.

[0247] Subcarrier elements with the same phase shift can be grouped into subcarrier groups. A first subcarrier group (subcarrier group index = 1) can be configured to include subcarriers 1960 and 1930 corresponding to RE indices 0 and 6, a second subcarrier group (subcarrier group index = 2) can be configured to include subcarriers 1950 and 1920 corresponding to RE indices 2 and 8, and a third subcarrier group (subcarrier group index = 3) can be configured to include subcarriers 1940 and 1910 corresponding to RE indices 4 and 10. The calibrationRSList 1970 can include calibrationRS (=1) for a first 2-port CSI-RS resource relating to the calculation of the phase shift applied in the first subcarrier group with the lowest subcarrier group index, calibrationRS (=5) for a second 2-port CSI-RS resource relating to the calculation of the phase shift applied in the second subcarrier group with the second lowest subcarrier group index, and a third 2-port CSI-RS resource relating to the calculation of the phase shift applied in the third subcarrier group with the highest subcarrier group index. The calibration RS of the I-RS resource is 3. and The phase shift can be applied to the SRS transmitted in the first to third subcarrier groups, respectively.

[0248] Reference Figure 19 The pairs of subcarrier indices included in the first, second, and third subcarrier groups are merely examples, and it is obvious that the subcarrier groups can be modified and configured differently. Furthermore, assigning subcarrier group indices to the first, second, and third subcarrier groups is only an example, and it is evident that they can be used in conjunction with... Figure 19 The system employs various methods to allocate subcarrier group indices, and the calibrationRSList can be configured based on the ascending order of the allocated group indices. Additionally, it... Figure 19 The difference lies in the RB that transmits the SRS. and The location of subcarriers with different phase shifts can be configured via RRC signaling.

[0249] The parameters that must be included in the RRC configuration IE for the phase calibration method used in this disclosure will be described below.

[0250] The parameter nrofSymbols must be included in the parameter resourceMapping, which is included in the parameter SRS-Resource used to indicate SRS resources.

[0251] The parameter nrofSymbols can be included in the RRC configuration IE in the format shown in Table 2 below:

[0252] Table 2

[0253]

[0254] If an SRS for phase calibration is configured for both consecutive symbols n and symbol (n+1) of the transmitted SRS, the parameter nrofSymbols can be configured such that nrofSymbols=n2.

[0255] Alternatively, in conjunction with the consecutive symbols n and (n+1) of the transmitted SRS, if the SRS is configured for symbol n using one of {beam management, codebook, non-codebook, antenna switching}, and if the SRS is configured for symbol (n+1) using {calibration}, then the parameter nrofSymbols can be configured such that nrofSymbols=n1.

[0256] In particular, if the SRS is used for SRS-based beamforming (BF) applications other than phase calibration, the additional SRS allocation may be a burden. In this case, the SRS for calibration purposes can be additionally allocated to only one symbol at a location adjacent to the already allocated SRS symbol location.

[0257] Figure 20 An example of configuring the necessary RRC configuration parameters according to an embodiment of this disclosure is shown.

[0258] refer to Figure 20 Combining the consecutive symbols 12 2010 and 13 2020 that transmit SRS 2023, if SRS is configured for symbol 12 using one of {beam management, codebook, non-codebook, antenna switching}, then SRS can be configured for symbol 13 such that SRS uses = {calibration}, and then the parameter nrofSymbols can be configured such that nrofSymbols = n.

[0259] Additionally, the parameter freqHopping IE may need to be included, which is incorporated into the parameter SRS-Resource used to indicate SRS resources. If frequency hopping is enabled, c-SRS, b-SRS, and b-hop can be configured equally for two consecutive SRS symbols.

[0260] Figure 21 An example of a feedback scheme for phase calibration between received signals is shown according to an embodiment of the present disclosure.

[0261] In operation 2110, UE 2101 has a 2-port CSI-RS assigned to it from either TRP 1 2103 or TRP 2 2105 that performs phase calibration. From the UE's perspective, UE 2101 has the 2-port CSI-RS assigned to it (logically), but may not know from which TRP which CSI-RS is being sent. That is, UE 2101 receiving CSI-RS from each of TRP 1 2103 and TRP 2 2105 can be understood as a UE-transparent operation.

[0262] In operation 2120, UE 2101 can receive configuration related to the SRS to be sent for phase calibration from TRP 1 2103 or TRP 2 2105 which performs phase calibration.

[0263] In operation 2130, the 2-port CSI-RS assigned to UE 2101 from TRP 1 2103 or TRP 2 2105 can be virtualized into a 1-port CSI-RS and then sent to UE 2102 from TRP 1 2103 or TRP 2 2105 respectively.

[0264] In operations 2140 and 2150, UE 2101 can calculate the phase of the CSI-RS from each received 2-port CSI-RS, and can calculate the phase difference between the received signals based on the calculated phase value.

[0265] In operations 2160 and 2170, UE 2101 may transmit SRS to TRP 22105, which performs phase calibration, on two adjacent symbols. A phase shift may not be applied to the SRS transmitted at the first symbol, but a phase shift corresponding to the phase difference calculated in operation 2140 may be applied to the SRS transmitted at the second symbol. Alternatively, if the phase difference between the received signals is not calculated in operation 2150, UE 2101 may transmit SRS to TRP 22105, which performs phase calibration, on two adjacent symbols. A phase shift corresponding to the phase value calculated from CSI-RS received from TRP 1 2103 may be applied to the SRS transmitted at the first symbol, and a phase shift corresponding to the phase value calculated from CSI-RS received from TRP 2 2105 may be applied to the SRS transmitted at the second symbol.

[0266] In operation 2180, TRP 2 2105 can estimate the phase difference by dividing the value of the SRS signal received at the (n+1)th symbol by the value of the SRS signal received at the nth symbol ((y(n+1) / y(n) operation).

[0267] Subsequently, in operation 2190, TRP 2 2105 can perform phase calibration based on the phase difference estimated in operation 2180.

[0268] After that, despite Figure 21 It is not shown in the diagram, but the UE can receive the first downlink data from TRP 1 and the second downlink data, which has undergone phase calibration, from TRP 2.

[0269] This disclosure enables phase calibration for CJTs to be performed at the PRB level. Furthermore, this disclosure allows for more accurate phase difference estimation compared to codebook-based feedback schemes that use limited overhead to feed back the phase difference. Moreover, this disclosure allows phase calibration to be performed based on the estimated phase difference, thereby maximizing CJT performance (= DL throughput).

[0270] Figure 22 This is a flowchart illustrating an example of a method for performing an operation of a UE according to an embodiment of the present disclosure.

[0271] refer to Figure 22 In operation 2210, the UE can receive a first channel state information reference signal (CSI-RS) from each of at least one first transmit / receive point (TRP).

[0272] Next, at operation 2220, the UE can receive the second CSI-RS from the second TRP.

[0273] Next, the UE can estimate at least one first phase value of each of the first CSI-RS received from each of at least one first TRP based on the first CSI-RS received from each of at least one first TRP at operation 2230.

[0274] Subsequently, in operation 2240, the UE can estimate the second phase value of the second CSI-RS based on the second CSI-RS.

[0275] Next, in operation 2250, the UE may, based on the phase shift using at least one first phase value and a second phase value, transmit a first probe reference signal (SRS) and a second SRS to each of at least one first TRP on different adjacent symbols.

[0276] Figure 23 This is a flowchart illustrating an example of a method for performing a TRP operation according to an embodiment of the present disclosure.

[0277] refer to Figure 23 In operation 2310, TRP can send the first CSI-RS to the user equipment (UE).

[0278] Next, in operation 2320, the TRP can receive the first SRS and the second SRS on different adjacent symbols from the UE based on the phase shift of the first phase value of the first CSI-RS estimated based on the first CSI-RS and the second phase value of the second CSI-RS estimated based on the second TRP.

[0279] Next, in operation 2330, the TRP can apply phase compensation between the first TRP and the second TRP, based on the phase shift received using the first phase value and the second phase value, to the first downlink data.

[0280] Next, in operation 2340, the TRP can send the first downlink data to the UE where phase compensation is applied.

[0281] The methods disclosed in the claims and / or the methods of the embodiments described in this disclosure may be implemented by hardware, software, or a combination of hardware and software.

[0282] When the method is implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). The one or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors within an electronic device. The at least one program includes instructions to cause the electronic device to perform a method according to various embodiments of the present disclosure as defined by the appended claims and / or disclosed herein.

[0283] These programs (software modules or software) can be stored in non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), disk storage devices, optical disc ROM (CD-ROM), digital versatile optical disc (DVD), or other types of optical storage devices or magnetic tape cartridges. Alternatively, any combination of some or all of these can form a memory storing programs. Furthermore, multiple such memories can be included in an electronic device.

[0284] Furthermore, the program can be stored in an attachable storage device that can be accessed by the electronic device via a communication network such as the Internet, intranet, local area network (LAN), wide area network (WLAN), and storage area network (SAN), or a combination thereof. Such a storage device can access the electronic device via an external port. Additionally, a separate storage device on the communication network can access portable electronic devices.

[0285] In the detailed embodiments described above, elements included in this disclosure are represented in a singular or plural form according to the presented embodiments. However, for ease of description, the singular or plural form is suitably chosen for the presented situation, and this disclosure is not limited to elements represented in a singular or plural form. Thus, an element represented in a plural form may also include a single element, or an element represented in a singular form may include multiple elements.

[0286] While this disclosure has been shown and described with reference to various embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of this disclosure as defined by the appended claims and their equivalents.

Claims

1. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: Receive a first channel state information reference signal (CSI-RS) from each of at least one first transmit / receive point (TRP); Receive the second CSI-RS from the second TRP; Based on the first CSI-RS received from each of the at least one first TRP, at least one first phase value of each of the first CSI-RS received from each of the at least one first TRP is estimated; The second phase value is estimated based on the second CSI-RS; as well as Based on the phase shift using the at least one first phase value and the second phase value, a first probe reference signal (SRS) and a second SRS are transmitted to each of the at least one first TRP on different adjacent symbols.

2. The method according to claim 1, in, On the second SRS, the phase shift includes at least one phase difference value subtracted from each of the at least one first phase value from the second phase value, and The second SRS includes the SRS applied to each of the at least one phase difference.

3. The method according to claim 1, in, Phase shift includes at least one first phase value and a second phase value. Wherein, the first SRS includes the SRS to which the second phase value is applied, and The second SRS includes the SRS applied to each of the at least one first phase value.

4. The method according to claim 1, further comprising: Receive first downlink data from each of the at least one first TRP; as well as Receive second downlink data from the second TRP. The phase compensation between each of the at least one first TRP and the second TRP is used based on the phase shift of the first SRS and the second SRS transmitted using the at least one first phase value and the second phase value, and the phase compensation is applied to each of the first downlink data received from each of the at least one first TRP.

5. The method according to claim 1, further comprising: Configuration information is received from at least one first TRP or second TRP, the configuration information including information about the SRS resource set associated with the transmission of the first SRS and the second SRS. The information regarding the SRS resource set includes information indicating that a first SRS and a second SRS are transmitted for phase compensation between the at least one first TRP and each of the second TRPs, and information regarding the SRS resources on which the first SRS and the second SRS are transmitted. The information regarding SRS resources includes information about the identifier (ID) on the CSI-RS resources on which the first CSI-RS of each of the at least one first TRP and the second CSI-RS of the second TRP are transmitted, and information about the number of resource blocks (RBs) in the frequency domain on which phase shift is applied to the first SRS and the second SRS.

6. A method performed by a first transmitting / receiving point (TRP) in a wireless communication system, the method comprising: Send the first channel state information reference signal (CSI-RS) to the user equipment (UE); Based on the phase shift using the first phase value of the first CSI-RS estimated based on the first CSI-RS and the second phase value of the second CSI-RS estimated based on the second TRP, the first detection reference signal (SRS) and the second SRS are received from the UE on different adjacent symbols, respectively. Phase compensation between the first TRP and the second TRP of the first SRS and the second SRS received using a phase shift based on the first phase value and the second phase value is applied to the first downlink data; as well as Send the first downlink data to the UE where phase compensation is applied.

7. The method according to claim 6, in, On the second SRS, the phase shift includes the phase difference in which the first phase value is subtracted from the second phase value, and The second SRS includes the SRS to which the phase difference value is applied.

8. The method according to claim 6, in, Phase shift includes a first phase value and a second phase value. Wherein, the first SRS includes the SRS to which the second phase value is applied, and The second SRS includes the SRS to which the first phase value is applied.

9. The method according to claim 6, further comprising: Based on the first and second SRSs on which phase shifts are applied, a phase difference is calculated where the first phase value is subtracted from the second phase value, wherein the phase difference is the average of the phase differences calculated individually on the subcarriers on which the first and second SRSs are mapped within the resource block (RB) on which they are transmitted; and The validity of the calculated phase difference is identified based on the phase difference value used before the phase difference value is calculated and a pre-configured threshold.

10. The method of claim 6, further comprising: The configuration information is sent to the UE, including information about the SRS resource set associated with the transmission of the first SRS and the second SRS. The information regarding the SRS resource set includes information indicating that a first SRS and a second SRS are transmitted for phase compensation between the at least one first TRP and each of the second TRPs, and information regarding the SRS resources on which the first SRS and the second SRS are transmitted. The information regarding SRS resources includes information about the identifier (ID) on the CSI-RS resources on which the first CSI-RS of each of the at least one first TRP and the second CSI-RS of the second TRP are transmitted, and information about the number of resource blocks (RBs) in the frequency domain on which phase shift is applied to the first SRS and the second SRS.

11. A user equipment (UE) in a wireless communication system, the UE comprising: transceiver; as well as The controller, coupled to the transceiver, is configured to: Receive a first channel state information reference signal (CSI-RS) from each of at least one first transmit / receive point (TRP). Receive the second CSI-RS from the second TRP. Based on the first CSI-RS received from each of the at least one first TRP, estimate at least one first phase value for each of the first CSI-RS received from each of the at least one first TRP. The second phase value is estimated based on the second CSI-RS, and Based on the phase shift using the at least one first phase value and the second phase value, a first probe reference signal (SRS) and a second SRS are transmitted to each of the at least one first TRP on different adjacent symbols.

12. The UE according to claim 11, in, On the second SRS, the phase shift includes at least one phase difference value subtracted from each of the at least one first phase value from the second phase value, and The second SRS includes the SRS applied to each of the at least one phase difference.

13. The UE according to claim 11, in, Phase shift includes at least one first phase value and a second phase value. Wherein, the first SRS includes the SRS to which the second phase value is applied, and The second SRS includes the SRS applied to each of the at least one first phase value.

14. The UE according to claim 11, in, The controller is also configured to: Receive first downlink data from each of the at least one first TRP; Receive second downlink data from the second TRP, and The phase compensation between each of the at least one first TRP and the second TRP is used based on the phase shift of the first SRS and the second SRS transmitted using the at least one first phase value and the second phase value, and the phase compensation is applied to each of the first downlink data received from each of the at least one first TRP.

15. A first transmitting / receiving point (TRP) in a wireless communication system, the first TRP comprising: transceiver; as well as The controller, coupled to the transceiver, is configured to: Send the first Channel State Information Reference Signal (CSI-RS) to the User Equipment (UE). Based on the phase shift using the first phase value of the first CSI-RS estimated based on the first CSI-RS and the second phase value of the second CSI-RS estimated based on the second TRP, the first detection reference signal (SRS) and the second SRS are received from the UE on different adjacent symbols. Phase compensation between the first TRP and the second TRP of the first SRS and the second SRS, based on phase shifts received using the first phase value and the second phase value, is applied to the first downlink data, and Send the first downlink data to the UE where phase compensation is applied.

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