Method and apparatus for PMI-based div-jt in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a data transmission rate higher than that of a 4G communication system such as LTE. Specifically, according to various embodiments of the present disclosure, a method performed by a terminal in a wireless communication system comprises the steps of: receiving, from a first base station, configuration information related to PMI-based cooperative transmission; receiving, from the first base station, a first CSI-RS on the basis of the configuration information; receiving, from a second base station, a second CSI-RS on the basis of the configuration information; and transmitting, to the first base station, a CSI report including a measurement result for each of the first CSI-RS and the second CSI-RS and information related to the cooperative transmission.

Description

Method and apparatus for PMI-based DIV-JT in a wireless communication system

[0001] The present disclosure generally relates to wireless communication systems, and more specifically to an apparatus and method for performing precoding matrix indicator (PMI)-based joint transmission (JT) in a wireless communication system.

[0002] Looking back at the evolution of wireless communication through successive generations, technologies have been developed primarily for human-oriented services, such as voice, multimedia, and data. Following the commercialization of 5G (5th Generation) communication systems, connected devices, which have been increasing explosively, are expected to be connected to communication networks. Examples of networked 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, such as augmented reality glasses, virtual reality headsets, and holographic devices. In the 6G (6th Generation) era, efforts are underway to develop improved 6G communication systems to connect hundreds of billions of devices and objects to provide diverse services. For this reason, 6G communication systems are being referred to as "beyond 5G" systems.

[0003] In the 6G communication system predicted to be realized around 2030, the maximum transmission speed is tera (i.e., 1,000 gigabit) bps (bit per second), and the wireless latency is 100 microseconds (μsec). In other words, compared to the 5G communication system, the transmission speed in the 6G communication system is 50 times faster, and the wireless latency is reduced to one-tenth.

[0004] To achieve such high data transmission speeds and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz (THz) band (e.g., the 95 gigahertz (GHz) to 3 terahertz (3THz) band). Due to more severe path loss and atmospheric absorption phenomena compared to the millimeter wave (mmWave) band introduced in 5G, the importance of technologies capable of guaranteeing signal reach, or coverage, is expected to increase in the terahertz band. As key technologies to ensure coverage, new waveforms, beamforming, and multi-antenna transmission technologies such as massive Multiple-Input and Multiple-Output (MIMO), Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas, which are superior in terms of coverage compared to RF (Radio Frequency) devices, antennas, and OFDM (Orthogonal Frequency Division Multiplexing), must be developed. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), and Reconfigurable Intelligent Surface (RIS) are being discussed to improve the coverage of terahertz band signals.

[0005] In addition, to improve frequency efficiency and system network, development is underway in 6G communication systems for full duplex technology, in which uplink and downlink simultaneously utilize the same frequency resources at the same time; network technology that integrates satellites and HAPS (High-Altitude Platform Stations); network structure innovation technology that supports mobile base stations and enables network operation optimization and automation; dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; AI-based communication technology that utilizes AI (Artificial Intelligence) from the design stage and internalizes end-to-end AI support functions to realize system optimization; and next-generation distributed computing technology that realizes services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high performance communication and computing resources (Mobile Edge Computing (MEC), cloud, etc.). In addition, attempts are continuing to further strengthen connectivity between devices, further optimize networks, promote the softwareization of network entities, and increase the openness of wireless communication 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 the safe utilization of data, and the development of technologies regarding privacy maintenance methods.

[0006] Due to the research and development of such 6G communication systems, it is expected that a new dimension of hyper-connected experience will become possible through the hyper-connectivity of 6G communication systems, which encompasses not only connections between objects but also connections between people and objects. Specifically, it is projected that 6G communication systems will enable the provision of services such as truly immersive eXtended Reality (XR), high-fidelity mobile holograms, and digital replicas. Furthermore, services such as remote surgery, industrial automation, and emergency response, which are provided through 6G communication systems with enhanced security and reliability, will be applied in various fields including industry, healthcare, automotive, and home appliances.

[0007] Meanwhile, multiple transmission / reception point (mTRP) techniques, which improve transmission efficiency by utilizing multiple base stations as MIMO (multiple-input and multiple-output) antennas, can take various forms and are being proposed through 3GPP (3rd Generation Partnership Project) standard specifications. On the other hand, diversity joint transmission (DIV-JT) techniques have been proposed as one form of cooperation technology between TRPs. Current standard specifications also define a DIV-JT method based on PMI (precoding matrix indicator) feedback. However, since it is configured under the premise of UE transparency, there may be limitations to the performance improvement effects obtainable from PDSCH (physical downlink shared channel) transmission, and new measures are being sought to address this issue.

[0008] Various embodiments of the present disclosure aim to provide devices and methods capable of effectively providing services in a wireless communication system.

[0009] According to various embodiments of the present disclosure, a method performed by a terminal of a wireless communication system comprises: receiving configuration information regarding a precoding matrix indicator (PMI)-based joint transmission from a first base station; receiving a first channel state information (CSI)-RS (reference signal) from the first base station based on the configuration information; receiving a second CSI-RS from the second base station based on the configuration information; and transmitting a CSI report to the first base station that includes measurement results for each of the first CSI-RS and the second CSI-RS and information related to the joint transmission, wherein the joint transmission may include the transmission of the same data from each of the first base station and the second base station to the terminal that supports coordinated multi-point operation (CoMP).

[0010] According to various embodiments of the present disclosure, a method performed by a first base station of a wireless communication system comprises: transmitting configuration information regarding a precoding matrix indicator (PMI)-based joint transmission to a terminal; transmitting said configuration information to a second base station; transmitting a first channel state information (CSI) reference signal (RS) to the terminal based on said configuration information; and receiving from the terminal a CSI report including measurement results for each of the first CSI-RS and the second CSI-RS and information related to said joint transmission, wherein the second CSI-RS is transmitted from the second base station to the terminal based on said configuration information, and said joint transmission may include the transmission of the same data from each of the first base station and the second base station to the terminal that supports coordinated multi-point operation (CoMP).

[0011] According to various embodiments of the present disclosure, a terminal of a wireless communication system comprises a transceiver and at least one control unit connected to the transceiver, wherein the at least one control unit receives configuration information regarding a precoding matrix indicator (PMI)-based joint transmission from a first base station, receives a first channel state information (CSI) reference signal (RS) from the first base station based on the configuration information, receives a second CSI-RS from the second base station based on the configuration information, and is configured to transmit to the first base station a CSI report including measurement results for each of the first CSI-RS and the second CSI-RS and information related to the joint transmission, and the joint transmission may include the transmission of the same data from each of the first base station and the second base station to the terminal that supports coordinated multi-point operation (CoMP).

[0012] According to various embodiments of the present disclosure, a first base station of a wireless communication system comprises a transceiver and at least one control unit connected to the transceiver, wherein the at least one control unit transmits configuration information regarding a precoding matrix indicator (PMI)-based joint transmission to a terminal, transmits the configuration information to a second base station, transmits a first channel state information (CSI) reference signal (RS) to the terminal based on the configuration information, and is configured to receive a CSI report from the terminal that includes measurement results for each of the first CSI-RS and the second CSI-RS and information related to the joint transmission, wherein the second CSI-RS is transmitted from the second base station to the terminal based on the configuration information, and the joint transmission may include the transmission of the same data from each of the first base station and the second base station to the terminal that supports coordinated multi-point operation (CoMP).

[0013] Various embodiments of the present disclosure aim to provide devices and methods capable of effectively providing services in a wireless communication system. More specifically, according to various embodiments of the present disclosure, in order to improve throughput gains from cooperative transmission, a terminal can reduce the burden on a base station by utilizing channel information from a serving TRP (multiple transmission / reception point) and a non-serving TRP to obtain additional information regarding cooperative transmission and reporting it to the serving TRP. Additionally, the terminal can transmit only partial information to the non-serving TRP, thereby reducing the overhead of uplink transmission and enabling energy saving for the terminal. Furthermore, if the gain from the current cooperative transmission does not reach a certain level, cooperative transmission can be stopped through separate signaling, thereby allowing for the determination of a transmission method according to the situation.

[0014] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0015] FIG. 1 illustrates an example of a wireless communication environment according to embodiments of the present disclosure.

[0016] FIG. 2 illustrates an example of the configuration of a base station in a wireless communication system according to embodiments of the present disclosure.

[0017] FIG. 3 illustrates an example of the configuration of a terminal in a wireless communication system according to embodiments of the present disclosure.

[0018] FIG. 4 illustrates the concept of a precoding matrix indicator (PMI)-based diversity joint transmission (DIV-JT) technique related to embodiments of the present disclosure.

[0019] FIG. 5 illustrates the operation of a terminal in a PMI-based DIV-JT technique related to embodiments of the present disclosure.

[0020] FIG. 6a illustrates an example of a non-periodic PMI-based DIV-JT technique in a wireless communication system according to embodiments of the present disclosure.

[0021] FIG. 6b illustrates an extended example of a non-periodic PMI-based DIV-JT technique in a wireless communication system according to embodiments of the present disclosure.

[0022] FIG. 7a illustrates an example of a periodic PMI-based DIV-JT technique in a wireless communication system according to embodiments of the present disclosure.

[0023] FIG. 7b illustrates an extended example of a periodic PMI-based DIV-JT technique in a wireless communication system according to embodiments of the present disclosure.

[0024] FIG. 8 illustrates a setup for performing PMI-based DIV-JT in a wireless communication system according to embodiments of the present disclosure.

[0025] FIG. 9 illustrates settings for performing PMI-based DIV-JT in a wireless communication system according to embodiments of the present disclosure.

[0026] FIG. 10a illustrates an example of cooperative transmission in a wireless communication system according to embodiments of the present disclosure.

[0027] FIG. 10b illustrates the flow of signals in cooperative transmission in a wireless communication system according to embodiments of the present disclosure.

[0028] FIG. 11a illustrates an example of non-cooperative transmission in a wireless communication system according to embodiments of the present disclosure.

[0029] FIG. 11b illustrates the flow of signals in non-cooperative transmission in a wireless communication system according to embodiments of the present disclosure.

[0030] FIG. 12 illustrates the flow of signals for stopping cooperative transmission in a wireless communication system according to embodiments of the present disclosure.

[0031] FIG. 13 illustrates the operation of a terminal for performing a PMI-based DIV-JT technique in a wireless communication system according to embodiments of the present disclosure.

[0032] FIG. 14 illustrates the operation of a serving TRP (transmission / reception point) for performing a PMI-based DIV-JT technique in a wireless communication system according to embodiments of the present disclosure.

[0033] In relation to the description of the drawings, the same or similar reference numerals may be used for identical or similar components.

[0034] The terms used in this disclosure are used merely to describe specific embodiments and are not intended to limit the scope of other embodiments. A singular expression may include a plural expression unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by those skilled in the art described in this disclosure. Terms used in this disclosure that are defined in a general dictionary may be interpreted as having the same or similar meaning as they have in the context of the relevant technology, and are not to be interpreted in an ideal or overly formal sense unless explicitly defined in this disclosure. In some cases, even terms defined in this disclosure are not to be interpreted to exclude the embodiments of this disclosure.

[0035] In the various embodiments of the present disclosure described below, a hardware-based approach is described as an example. However, since the various embodiments of the present disclosure include techniques using both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

[0036] Terms referring to components of a device used in the following description (control unit, processor, artificial intelligence (AI) model, encoder, decoder, autoencoder (AE), neural network (NN) model, etc.) and terms referring to data (signal, feedback, report, reporting, information, parameter, value, bit, codeword, etc.) are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms having similar or equivalent technical meanings may be used.

[0037] Additionally, the present disclosure describes various embodiments using terms used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project)), but this is merely illustrative. Various embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0038] In the present disclosure, the downlink channel may be either a physical downlink control channel (PDCCH) or a physical downlink shared channel (PDSCH). In the present disclosure, the uplink channel may be either a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH). Additionally, in the present disclosure, uplink data may be data transmitted and / or received over the uplink channel described above, and downlink data may be data transmitted and / or received over the downlink channel described above.

[0039] FIG. 1 illustrates a wireless communication system according to various embodiments of the present disclosure. FIG. 1 illustrates a base station (110), a terminal (120), and a terminal (130) as part of nodes utilizing a wireless channel in a wireless communication system. FIG. 1 illustrates only one base station, but other base stations identical or similar to the base station (110) may be additionally included.

[0040] A base station (110) is a network infrastructure that provides wireless access to terminals (120, 130). The base station (110) has coverage defined as a certain geographical area based on the distance at which it can transmit signals. In addition to being a base station, the base station (110) may be referred to as an 'access point (AP)', 'eNodeB (eNB)', 'gNodeB (gNB)', '5G node (5th generation node)', '6G node (6th generation node)', 'wireless point', 'transmission / reception point (TRP)', or other terms having an equivalent technical meaning.

[0041] Each of the terminal (120) and terminal (130) is a device used by a user and performs communication with the base station (110) via a wireless channel. In some cases, at least one of the terminal (120) and terminal (130) may be operated without user involvement. That is, at least one of the terminal (120) and terminal (130) is a device that performs machine type communication (MTC) and may not be carried by the user. Each of the terminal (120) and terminal (130) may be referred to as 'terminal', 'user equipment (UE)', 'mobile station', 'subscriber station', 'customer premises equipment (CPE)', 'remote terminal', 'wireless terminal', 'electronic device', or 'user device', or other terms having a similar or equivalent technical meaning.

[0042] A base station (110), a terminal (120), and a terminal (130) can transmit and receive wireless signals in a millimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 38 GHz, 60 GHz, over 60 GHz, etc.). At this time, to improve channel gain, the base station (110), the terminal (120), and the terminal (130) can perform beamforming. Here, beamforming may include transmission beamforming and reception beamforming. That is, the base station (110), the terminal (120), and the terminal (130) can impart directivity to the transmission signal or the reception signal. To this end, the base station (110) and the terminal (120, 130) can select serving beams (112, 113, 121, 131) through a beam search or beam management procedure. After serving beams (112, 113, 121, 131) are selected, subsequent communication can be performed through a resource that is in a quasi-co-located (QCL) relationship with the resource that transmitted the serving beams (112, 113, 121, 131).

[0043] FIG. 2 illustrates an example of the configuration of a base station in a wireless communication system according to embodiments of the present disclosure. According to various embodiments of the present disclosure, the base station (110) may be referred to as a network for convenience. The configuration exemplified in FIG. 2 can be understood as the configuration of the base station (110). Terms such as '~unit', '~unit', etc. used below refer to a unit that processes at least one function or operation, and this may be implemented in hardware or software, or a combination of hardware and software.

[0044] Referring to FIG. 2, the base station (110) may include a wireless communication unit (210), a backhaul communication unit (220), a storage unit (230), and a control unit (240).

[0045] The wireless communication unit (210) performs functions for transmitting and receiving signals through a wireless channel. For example, the wireless communication unit (210) performs a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting data, the wireless communication unit (210) generates complex symbols by encoding and modulating the transmitted bit sequence. Also, when receiving data, the wireless communication unit (210) restores the received bit sequence by demodulating and decoding the baseband signal. Additionally, the wireless communication unit (210) upconverts the baseband signal into an RF (radio frequency) band signal and transmits it through an antenna, and downconverts the RF band signal received through the antenna into a baseband signal.

[0046] To this end, the wireless communication unit (210) may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), etc. Additionally, the wireless communication unit (210) may include a plurality of transmitting and receiving paths. Furthermore, the wireless communication unit (210) may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the wireless communication unit (210) may be composed of a digital unit and an analog unit, and the analog unit may be composed of a plurality of sub-units depending on operating power, operating frequency, etc.

[0047] The wireless communication unit (210) can transmit and receive signals. To this end, the wireless communication unit (210) may include at least one transceiver. For example, the wireless communication unit (210) can transmit a synchronization signal, a reference signal, system information, a message, control information, or data. Additionally, the wireless communication unit (210) can perform beamforming.

[0048] The wireless communication unit (210) transmits and receives signals as described above. Accordingly, all or part of the wireless communication unit (210) may be referred to as a 'transmitter', a 'receiver', or a 'transmitter / receiver'. Furthermore, in the following description, transmission and reception performed through a wireless channel are used to mean that processing as described above is performed by the wireless communication unit (210).

[0049] The backhaul communication unit (220) provides an interface for communicating with other nodes within the network. That is, the backhaul communication unit (220) converts a bit sequence transmitted from the base station (110) to other nodes, such as other connection nodes, other base stations, upper nodes, core networks, etc., into a physical signal, and converts a physical signal received from other nodes into a bit sequence.

[0050] The storage unit (230) stores data such as basic programs, application programs, and configuration information for the operation of the base station (110). The storage unit (230) may include memory. The storage unit (230) may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. Additionally, the storage unit (230) may provide the stored data upon request from the control unit (240).

[0051] The control unit (240) controls the overall operations of the base station (110). For example, the control unit (240) transmits and receives signals through the wireless communication unit (210) or through the backhaul communication unit (220). Additionally, the control unit (240) writes and reads data to and from the storage unit (230). Furthermore, the control unit (240) can perform the functions of a protocol stack required by the communication standard. To this end, the control unit (240) may include at least one processor.

[0052] Although not illustrated in FIG. 2, according to various embodiments of the present disclosure, the base station (110) may further include a receiving device for performing embodiments of the present disclosure. Specifically, the receiving device may be included in the wireless communication unit (210) or may be included in the base station (110) separately from the wireless communication unit (210). Alternatively, the receiving device may exist outside the base station (110) and be connected to the base station (110) wirelessly or via a wire. In this case, the receiving device may include at least one receiver. Additionally, the control unit (240) may control the receiving device to perform embodiments of the present disclosure below.

[0053] The configuration of the base station (110) shown in FIG. 2 is merely one example of a base station, and the examples of base stations for performing various embodiments of the present disclosure are not limited to the configuration shown in FIG. 2. That is, depending on various embodiments, some configurations may be added, deleted, or changed.

[0054] In FIG. 2, the base station is described as a single entity, but the present disclosure is not limited thereto. A base station according to various embodiments of the present disclosure may be implemented to form an access network having a distributed deployment as well as an integrated deployment. According to one embodiment, the base station may be distinguished into a central unit (CU) and a digital unit (DU), wherein the CU may be implemented to perform upper layer functions (e.g., radio link control (RLC), packet data convergence protocol (PDCP), and radio resource control (RRC)), and the DU may be implemented to perform lower layer functions (e.g., medium access control (MAC), physical (PHY)). The DU of the base station may form beam coverage on a radio channel.

[0055] FIG. 3 illustrates the configuration of a terminal in a wireless communication system according to various embodiments of the present disclosure. The configuration exemplified in FIG. 3 can be understood as the configuration of a terminal (120). Terms such as ‘~part’, ‘~unit’ used below refer to a unit that processes at least one function or operation, and this may be implemented in hardware or software, or a combination of hardware and software.

[0056] Referring to FIG. 3, the terminal includes a communication unit (310), a storage unit (320), and a control unit (330).

[0057] The communication unit (310) performs functions for transmitting and receiving signals through a wireless channel. For example, the communication unit (310) performs a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting data, the communication unit (310) generates complex symbols by encoding and modulating the transmitted bit sequence. Also, when receiving data, the communication unit (310) restores the received bit sequence by demodulating and decoding the baseband signal. Additionally, the communication unit (310) upconverts the baseband signal into an RF band signal and transmits it through an antenna, and downconverts the RF band signal received through the antenna into a baseband signal. For example, the communication unit (310) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0058] Additionally, the communication unit (310) may include a plurality of transmission and reception paths. Furthermore, the communication unit (310) may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the communication unit (310) may be composed of a digital circuit and an analog circuit (e.g., a radio frequency integrated circuit (RFIC)). Here, the digital circuit and the analog circuit may be implemented as a single package. Additionally, the communication unit (310) may include a plurality of RF chains. Furthermore, the communication unit (310) may perform beamforming.

[0059] The communication unit (310) transmits and receives signals as described above. Accordingly, all or part of the communication unit (310) may be referred to as a 'transmitter', a 'receiver', or a 'transmitter / receiver'. Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean that processing as described above is performed by the communication unit (310).

[0060] The storage unit (320) stores data such as basic programs, application programs, and setting information for the operation of the terminal. The storage unit (320) may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. Additionally, the storage unit (320) provides the stored data upon the request of the control unit (330).

[0061] The control unit (330) controls the overall operations of the terminal. For example, the control unit (330) transmits and receives signals through the communication unit (310). Additionally, the control unit (330) writes and reads data to and from the storage unit (320). Furthermore, the control unit (330) can perform the functions of the protocol stack required by the communication standard. To this end, the control unit (330) may include at least one processor or microprocessor, or be part of a processor. Additionally, part of the communication unit (310) and the control unit (330) may be referred to as a communication processor (CP).

[0062] According to various embodiments, the control unit (330) can control the terminal to perform operations according to various embodiments described below.

[0063] Terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc., are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

[0064] The configuration of the terminal (120) shown in FIG. 3 is merely an example of a terminal, and the examples of terminals performing various embodiments of the present disclosure are not limited to the configuration shown in FIG. 3. That is, depending on various embodiments, some configurations may be added, deleted, or changed.

[0065] Meanwhile, the diversity joint transmission (DIV-JT) technique has been proposed as a form of the multiple transmission / reception point (mTRP) technique, which improves transmission efficiency by utilizing multiple base stations as MIMO (multiple-input and multiple-output) antennas. In particular, while the existing sounding reference signal (SRS)-based DIV-JT method involved non-serving TRPs also performing cooperative transmission based on the SRS transmitted by the terminal to the serving transmission / reception point (TRP), the DIV-JT proposed in this disclosure may be a method based on precoding matrix indicator (PMI) feedback. Accordingly, this disclosure proposes embodiments for efficiently executing the PMI-based DIV-JT technique. Prior to this, the PMI-based DIV-JT technique is described below.

[0066] PMI-based DIV-JT has a gain in terms of throughput (T_put) compared to the case where cooperative transmission is not performed (non-JT). For example, in the case where the bandwidth is 2100 MHz, the base station includes 4 transmitting antennas (4T), and the maximum number of transmission layers is 4, the gain of the signal strength of PDSCH (e.g., signal to interference plus noise ratio, SINR) at each TRP is measured to be higher in the case of cooperative transmission compared to non-cooperative transmission. Additionally, if the base station type is 32T and the number of transmitting antennas is greater, the difference in T_put between non-cooperative transmission and cooperative transmission can be even greater. Therefore, even if the gain of downlink transmission (e.g., PDSCH) at each TRP is the same, the T_put at the terminal can be improved in the case of cooperative transmission.

[0067] Meanwhile, in this disclosure, the term TRP may be used interchangeably with a node or base station that performs the transmission and / or reception of signals. Additionally, in this disclosure, a TRP that is connected (or associated) with a terminal and sets the information necessary to perform the transmission and reception of data with the terminal may be referred to as a serving TRP. Furthermore, a TRP that is not connected to a terminal but performs cooperative transmission based on the settings of a serving TRP may be referred to as a non-serving TRP, a helping TRP, or a secondary (assistance) TRP. Of course, the above-mentioned names are not limited to the examples provided, and the names described above are merely names intended to indicate the operations performed by each TRP. Meanwhile, in this disclosure, the serving TRP and the helping TRP are connected via a distributed unit (DU), and signaling between the serving TRP and the helping TRP may be transmitted / received via the DU. Therefore, the DU may be omitted in the following description and drawings, but this does not imply that the DU is not included.

[0068] FIG. 4 illustrates the concept of a PMI-based DIV-JT technique related to embodiments of the present disclosure.

[0069] Referring to FIG. 4, signals transmitted and received between a serving TRP, a cooperating TRP, and a terminal in a PMI feedback-based DIV-JT technique are described. In addition, a terminal receiving data through the cooperating transmission of TRPs in a PMI feedback-based DIV-JT technique may be referred to as a CoMP (coordinated multi-point operation) UE. However, in the present disclosure, a CoMP UE may be referred to as a terminal.

[0070] A terminal connected to a serving TRP can receive configuration information regarding CSI (channel state information)-RS from the serving TRP. Based on the configuration information regarding CSI-RS received from the serving TRP, the terminal can receive CSI-RS from the serving TRP and the cooperating TRP, respectively. Accordingly, the terminal can measure each channel based on the CSI-RS received from each TRP and can transmit a CSI report containing the channel measurement results to the serving TRP. At this time, the channel measurement results included in the CSI report are the respective channels of the serving TRP and the cooperating TRP ( At this time, refers to the serving TRP, It may include measurement results for (referring to collaborative TRP). For example, channel measurement results include PMI for each channel ( ), RI(rank indicator)( ), or CQI (channel quality indicator)( It may include at least one of ). And the serving TRP may transmit the channel measurement result received from the terminal to the cooperating TRP, and the channel measurement result transmitted to the cooperating TRP is the measurement result for the channel between the cooperating TRP and the terminal ( ), RI for the channel between the serving TRP and the terminal( ), the MCS (modulation and coding scheme) of the serving TRP( It may include at least one of ), or data (x) to be transmitted to the terminal. In this case, the information transmitted from the serving TRP to the cooperating TRP may be transmitted via the DU. Therefore, the serving TRP is the PMI( Downlink data based on ) ) can be transmitted to the terminal, and the cooperative TRP is PMI( Downlink data based on ) ) can be transmitted to the terminal. As described above, each TRP has the same downlink data ( ) can be transmitted to the terminal through transmit diversity. However, based on the channel state between the TRP and the terminal, the precoding matrix selected from a predefined codebook may differ. Additionally, SINR gains in the downlink (e.g., PDSCH) can be generated through cooperative transmission, thereby improving throughput (T_put).

[0071] FIG. 5 illustrates the operation of a terminal in a PMI-based DIV-JT technique related to embodiments of the present disclosure.

[0072] Referring to FIG. 5, the operation of a terminal (e.g., CoMP UE) receiving data through cooperative transmission of TRPs in the PMI feedback-based DIV-JT technique of FIG. 4 described above is explained. Therefore, explanations that overlap with FIG. 4 are omitted.

[0073] In step 510, a terminal connected to a serving TRP can receive configuration information regarding CSI-RS from the serving TRP. Based on the configuration information regarding CSI-RS received from the serving TRP, the terminal can receive CSI-RS from the serving TRP and the cooperating TRP, respectively.

[0074] In step 520, the terminal can measure each channel based on the CSI-RS received from each TRP and transmit a CSI report containing the channel measurement results to the serving TRP. At this time, the channel measurement results included in the CSI report are the channels of the serving TRP and the cooperating TRP, respectively ( Measurement results for ) (e.g., PMI( ), RI( ), or CQI( It may include at least one of ). And the serving TRP can receive channel measurement results from the terminal ( ), RI for the channel between the serving TRP and the terminal( ), Serving TRP's MCS( It can transmit at least one of ), or data (x) to be transmitted to the terminal.

[0075] In step 530, the terminal receives PMI from the serving TRP ( Downlink data based on ) ) can receive. In addition, the terminal receives PMI from the cooperative TRP( Downlink data based on ) ) can be received. Therefore, the terminal can receive the same downlink data through the cooperative transmission of the serving TRP and the cooperative TRP.

[0076] Meanwhile, the aforementioned PMI-based DIV-JT technique may include the following problems. For example, a PMI-based DIV-JT configured under the premise of terminal transparency may have a problem where it is difficult for the TRP to know the actual channel. Consequently, it may be difficult for the TRP to determine whether it can obtain T_put gain through cooperative transmission. In addition, the terminal may have different RIs for the Serving TRP and the Co-op TRP, respectively (e.g., different RIs for the Serving / Helping TRP, respectively By reporting this, a problem may arise where the feasibility of cooperative transmission varies depending on the RI relationship. Consequently, it may be difficult for TRPs to perform complete cooperative transmission. For example, in some cases, SU (single user)-MIMO may be performed by the serving TRP. Furthermore, the channel for the serving TRP ( CQI measured by considering only ) Based on ) MCS( ) was determined, and the collaborating TRP determined the MCS ( There may be a problem in transmitting downlink data using ). Accordingly, the present disclosure proposes a method to mitigate or resolve the above-mentioned problem.

[0077] FIG. 6a illustrates an example of a non-periodic PMI-based DIV-JT technique in a wireless communication system according to embodiments of the present disclosure.

[0078] Referring to FIG. 6a, an aperioditic cooperative transmission method is described for a terminal (e.g., CoMP UE) of two TRPs (e.g., serving TRP and cooperative TRP) according to the PMI-based DIV-JT method proposed in the present disclosure.

[0079] In step 601, the serving TRP may transmit configuration information for cooperative transmission (e.g., JT transmission configuration) to the terminal. The configuration information for cooperative transmission may be transmitted to the terminal via RRC signaling. Additionally, the configuration information for cooperative transmission may be included in the configuration information for the terminal's CSI reporting (e.g., CSI-RS configuration). For example, the configuration information for cooperative transmission may include information to instruct the terminal to report additional information required for cooperative transmission based on CSI-RS. The specific configuration of the configuration information for cooperative transmission is described below in FIGS. 8 and 9.

[0080] In step 602, the serving TRP may transmit control information (e.g., downlink control information, DCI) to the terminal for initiating cooperative transmission. For example, the control information for initiating cooperative transmission may include at least one of whether to perform PMI-based cooperative transmission, information regarding the method for determining PMI-based cooperative transmission, or information for indicating to the terminal the start time of cooperative transmission. Additionally, based on the control information of step 602, the terminal may modify or (re)configure control information (e.g., uplink control information, UCI) containing feedback information to be reported to the serving TRP in step 609 to report additional information necessary for cooperative transmission. Meanwhile, although not illustrated in FIG. 6a, control information for initiating cooperative transmission may also be transmitted to the cooperative TRP.

[0081] In step 603, the serving TRP may also transmit the configuration information for CSI reporting transmitted to the terminal in step 601 to the cooperating TRP. In this case, the configuration information for CSI reporting may be transmitted via the DU. As another example, the configuration information transmitted to the cooperating TRP in step 603 may not include the configuration information for cooperating transmission transmitted to the terminal in step 601 (e.g., information to instruct the terminal to report additional information required for cooperating transmission based on CSI-RS).

[0082] In step 604, the serving TRP may transmit CSI-RS to the terminal based on the configuration information for the CSI report in step 601. At this time, CSI-RS may be a reference signal for measuring the channel status between the serving TRP and the terminal.

[0083] In step 605, the serving TRP may transmit control information (e.g., DCI) to the terminal to trigger aperiodic CSI-RS transmission. For example, the terminal may identify that a CSI-RS transmission from the cooperating TRP may be performed aperiodicly based on the control information in step 605. As another example, the serving TRP may pre-configure aperiodic CSI-RS transmission from the cooperating TRP to the terminal through the configuration information for CSI reporting in step 601. In this case, step 605 may be omitted.

[0084] In step 606, the serving TRP may transmit control information (e.g., DCI) to indicate to the cooperating TRP when to transmit CSI-RS to the terminal. For example, the cooperating TRP can identify the time to transmit CSI-RS through the control information in step 606.

[0085] In step 607, the cooperating TRP can transmit CSI-RS to the terminal based on the configuration information for CSI reporting in step 603 and the control information in step 606 received from the serving TRP. For example, the cooperating TRP can transmit CSI-RS to the terminal according to the configuration information for CSI reporting in step 603 at a time indicated by the control information in step 606. In this case, the transmission of CSI-RS may be performed non-periodically.

[0086] In step 608, the terminal may perform channel measurement (or estimation) for each of the CSI-RS received in steps 604 and 607. For example, the terminal may measure the received CSI-RS to obtain measurement values ​​for each channel for CSI reporting. At this time, the measurement value for each channel may further include at least one of a PMI for each TRP, one RI and CQI for the cooperative transmission of the serving TRP and the cooperative TRP, or additional information required for cooperative transmission. However, in the example described above, the composition of the information to be included in the CSI report may vary depending on whether the cooperative information is performed and the entity deciding whether the cooperative information is performed (e.g., the terminal or the serving TRP).

[0087] In step 609, the terminal may transmit a CSI report containing the measurements from step 608 to the serving TRP. Therefore, unlike the description in FIGS. 4 and 5 above, the CSI report in step 609 may not include RI and CQI for all channels and may include additional information necessary for determining cooperative transmission.

[0088] The names of the non-periodic PMI-based DIV-JT procedures and each signaling are not limited to the examples above. Accordingly, at least one of the operations described above may be omitted, or at least one new operation may be added and performed in organic combination with the operations described above. Additionally, some of the operations described above may be combined into at least one operation or divided into two or more operations.

[0089] FIG. 6b illustrates an extended example of a non-periodic PMI-based DIV-JT technique in a wireless communication system according to embodiments of the present disclosure.

[0090] Referring to FIG. 6b, a non-periodic cooperative transmission method is described for a terminal (e.g., CoMP UE) of a plurality of TRPs (e.g., a serving TRP and N (N>1) cooperative TRPs) according to the PMI-based DIV-JT method proposed in the present disclosure. Accordingly, descriptions that overlap with FIG. 6a described above in the following embodiments may be omitted.

[0091] In step 611, the serving TRP may transmit configuration information for cooperative transmission (e.g., JT transmission configuration) to the terminal. For example, the configuration information for cooperative transmission may be transmitted to the terminal via RRC signaling. Additionally, the configuration information for cooperative transmission may be included in the configuration information for the terminal's CSI reporting (e.g., CSI-RS configuration). For example, the configuration information for cooperative transmission may include information to instruct the terminal to report additional information required for cooperative transmission based on CSI-RS.

[0092] In step 612, the serving TRP may transmit control information (e.g., DCI) for initiating cooperative transmission to the terminal. For example, the control information for initiating cooperative transmission may include at least one of whether to perform PMI-based cooperative transmission, information regarding the method for determining PMI-based cooperative transmission, or information for indicating to the terminal the start time of cooperative transmission. Additionally, based on the control information in step 612, the terminal may modify or (re)configure control information (e.g., UCI) containing feedback information to be reported to the serving TRP in step 619 to report additional information necessary for cooperative transmission. Meanwhile, although not illustrated in FIG. 6b, the control information for initiating cooperative transmission may also be transmitted to at least one cooperative TRP.

[0093] In step 613, the serving TRP may also transmit the configuration information for CSI reporting transmitted to the terminal in step 611 to each of the N cooperating TRPs. In this case, the configuration information for CSI reporting may be transmitted via the DU. As another example, the configuration information transmitted to the cooperating TRPs in step 613 may not include the configuration information for cooperating transmission transmitted to the terminal in step 611 (e.g., information to instruct the terminal to report additional information required for cooperating transmission based on CSI-RS).

[0094] In step 614, the serving TRP can transmit CSI-RS to the terminal based on the configuration information for the CSI report in step 611.

[0095] In step 615, the serving TRP may transmit control information (e.g., DCI) to the terminal to trigger aperiodic CSI-RS transmissions. For example, the terminal may identify that CSI-RS transmissions from cooperating TRPs may be performed aperiodically based on the control information in step 615. As another example, the serving TRP may pre-configure aperiodic CSI-RS transmissions from a cooperating TRP (e.g., cooperating TRP #1) to the terminal through the configuration information for CSI reporting in step 611. In this case, step 615 may be omitted.

[0096] In step 616, the serving TRP may transmit control information (e.g., DCI) to indicate when the cooperating TRP (e.g., cooperating TRP#1) transmits CSI-RS to the terminal. For example, the cooperating TRP (e.g., cooperating TRP#1) can identify the time to transmit CSI-RS through the control information in step 616.

[0097] In step 617, a cooperating TRP (e.g., cooperating TRP #1) may transmit CSI-RS to a terminal based on the configuration information for CSI reporting in step 613 and the control information in step 616 received from the serving TRP. For example, the cooperating TRP (e.g., cooperating TRP #1) may transmit CSI-RS to a terminal according to the configuration information for CSI reporting in step 613 at a time indicated by the control information in step 616. In this case, the transmission of CSI-RS may be performed non-periodically.

[0098] Steps 615 through 617 described above may be repeated in relation to N cooperative TRPs to perform cooperative transmission according to the present disclosure. For example, steps 615 through 617 described above may be repeated N times, corresponding to the number (N) of cooperative TRPs to perform cooperative transmission. Of course, when repeated N times, the receiving node of the control information corresponding to step 615 and the transmitting node of the CSI-RS corresponding to step 616 are each n (1 <n It may be the Nth cooperative TRP. Meanwhile, although the control information of step 615 described above is shown as being transmitted N times, the terminal may be notified of the non-periodic CSI-RS transmission of N cooperative TRPs through the initial transmission (e.g., step 615). Therefore, the signaling corresponding to step 615 may not be performed repeatedly for every N cooperative TRP.

[0099] In step 618, the terminal may perform channel measurement (or estimation) for each of the CSI-RS received in step 614 and the CSI-RS received in step 617 (e.g., CSI-RS received from each of N cooperating TRPs). For example, the terminal may measure the received CSI-RS to obtain measurement values ​​for each channel for CSI reporting. At this time, the measurement value for each channel may further include at least one of a PMI for each TRP, one RI and CQI for cooperating transmission of the serving TRP and cooperating TRP, or additional information required for cooperating transmission. However, in the example described above, the composition of the information to be included in the CSI report may vary depending on whether the cooperating information is performed and the entity determining whether the cooperating information is performed (e.g., the terminal or the serving TRP).

[0100] In step 619, the terminal may transmit a CSI report containing the measurements from step 618 to the serving TRP. Therefore, unlike the description in FIGS. 4 and 5 above, the CSI report in step 619 may not include RI and CQI for all channels and may include additional information necessary for determining cooperative transmission.

[0101] The names of the non-periodic PMI-based DIV-JT procedures and each signaling are not limited to the examples above. Accordingly, at least one of the operations described above may be omitted, or at least one new operation may be added and performed in organic combination with the operations described above. Additionally, some of the operations described above may be combined into at least one operation or divided into two or more operations.

[0102] FIG. 7a illustrates an example of a periodic PMI-based DIV-JT technique in a wireless communication system according to embodiments of the present disclosure.

[0103] Referring to FIG. 7a, a periodic cooperative transmission method for a terminal (e.g., CoMP UE) of two TRPs (e.g., serving TRP and cooperative TRP) is described according to the PMI-based DIV-JT method proposed in the present disclosure.

[0104] In step 701, the serving TRP may transmit configuration information for cooperative transmission (e.g., JT transmission configuration) to the terminal. For example, the configuration information for cooperative transmission may be transmitted to the terminal via RRC signaling. Additionally, the configuration information for cooperative transmission may be included in the configuration information for the terminal's CSI reporting (e.g., CSI-RS configuration). For example, the configuration information for cooperative transmission may include information to instruct the terminal to report additional information required for cooperative transmission based on CSI-RS. The specific configuration of the configuration information for cooperative transmission is described below in FIGS. 8 and 9.

[0105] In step 702, the serving TRP may transmit control information (e.g., DCI) for initiating cooperative transmission to the terminal. For example, the control information for initiating cooperative transmission may include at least one of whether to perform PMI-based cooperative transmission, information regarding the method for determining PMI-based cooperative transmission, or information for indicating to the terminal the start time of cooperative transmission. Additionally, based on the control information of step 702, the terminal may modify or (re)configure control information (e.g., UCI) containing feedback information to be reported to the serving TRP in step 707 to report additional information necessary for cooperative transmission. Meanwhile, although not illustrated in FIG. 7a, control information for initiating cooperative transmission may also be transmitted to the cooperative TRP.

[0106] In step 703, the serving TRP may also transmit the configuration information for CSI reporting transmitted to the terminal in step 701 to the cooperating TRP. In this case, the configuration information for CSI reporting may be transmitted via the DU. As another example, the configuration information transmitted to the cooperating TRP in step 703 may not include the configuration information for cooperating transmission transmitted to the terminal in step 701 (e.g., information to instruct the terminal to report additional information required for cooperating transmission based on CSI-RS).

[0107] In step 704, the serving TRP may transmit CSI-RS to the terminal based on the configuration information for the CSI report in step 701. At this time, CSI-RS may be a reference signal for measuring the channel status between the serving TRP and the terminal.

[0108] In step 705, the cooperating TRP can transmit CSI-RS to the terminal based on the configuration information for the CSI report in step 703 received from the serving TRP. At this time, the transmission of CSI-RS may be performed periodically.

[0109] In step 706, the terminal may perform channel measurement (or estimation) for each of the CSI-RS received in steps 704 and 705. For example, the terminal may measure the received CSI-RS to obtain measurement values ​​for each channel for CSI reporting. At this time, the measurement value for each channel may further include at least one of the PMI for each TRP, one RI and CQI for the cooperative transmission of the serving TRP and the cooperative TRP, or additional information required for cooperative transmission. However, in the example described above, the composition of the information to be included in the CSI report may vary depending on whether the cooperative information is performed and the entity determining whether the cooperative information is performed (e.g., the terminal or the serving TRP).

[0110] In step 707, the terminal may transmit a CSI report containing the measurements from step 706 to the serving TRP. Therefore, unlike the description in FIGS. 4 and 5 above, the CSI report in step 707 may not include RI and CQI for all channels and may include additional information necessary for determining cooperative transmission.

[0111] The names of the periodic PMI-based DIV-JT procedures and each signaling are not limited to the examples above. Accordingly, at least one of the operations described above may be omitted, or at least one new operation may be added and performed in organic combination with the operations described above. Additionally, some of the operations described above may be combined into at least one operation or divided into two or more operations.

[0112] FIG. 7b illustrates an extended example of a periodic PMI-based DIV-JT technique in a wireless communication system according to embodiments of the present disclosure.

[0113] Referring to FIG. 7b, a periodic cooperative transmission method for a terminal (e.g., CoMP UE) of a plurality of TRPs (e.g., a serving TRP and N (N>1) cooperative TRPs) is described according to the PMI-based DIV-JT method proposed in the present disclosure. Accordingly, descriptions that overlap with FIG. 7a described above in the following embodiments may be omitted.

[0114] In step 711, the serving TRP may transmit configuration information for cooperative transmission (e.g., JT transmission configuration) to the terminal. For example, the configuration information for cooperative transmission may be transmitted to the terminal via RRC signaling. Additionally, the configuration information for cooperative transmission may be included in the configuration information for the terminal's CSI reporting (e.g., CSI-RS configuration). For example, the configuration information for cooperative transmission may include information to instruct the terminal to report additional information required for cooperative transmission based on CSI-RS.

[0115] In step 712, the serving TRP may transmit control information (e.g., DCI) for initiating cooperative transmission to the terminal. For example, the control information for initiating cooperative transmission may include at least one of whether to perform PMI-based cooperative transmission, information regarding the method for determining PMI-based cooperative transmission, or information for indicating to the terminal the start time of cooperative transmission. Additionally, based on the control information in step 712, the terminal may modify or (re)configure control information (e.g., UCI) containing feedback information to be reported to the serving TRP in step 717 to report additional information necessary for cooperative transmission. Meanwhile, although not illustrated in FIG. 7b, the control information for initiating cooperative transmission may also be transmitted to at least one cooperative TRP.

[0116] In step 713, the serving TRP may also transmit the configuration information for CSI reporting transmitted to the terminal in step 711 to each of the N cooperating TRPs. In this case, the configuration information for CSI reporting may be transmitted via the DU. As another example, the configuration information transmitted to the cooperating TRPs in step 713 may not include the configuration information for cooperating transmission transmitted to the terminal in step 711 (e.g., information to instruct the terminal to report additional information required for cooperating transmission based on CSI-RS).

[0117] In step 714, the serving TRP can transmit CSI-RS to the terminal based on the configuration information for the CSI report in step 711.

[0118] In step 715, a cooperating TRP (e.g., cooperating TRP #1) may transmit CSI-RS to a terminal based on the configuration information for the CSI report of step 713 received from the serving TRP. At this time, the transmission of CSI-RS may be performed periodically. Step 715 may be repeated by N cooperating TRPs to perform the cooperating transmission according to the present disclosure. For example, the above-described step 715 may be repeated N times, corresponding to the number (N) of cooperating TRPs to perform the cooperating transmission. Of course, when repeated N times, the transmission nodes of the CSI-RS corresponding to step 715 are each n (1 <n It could be the Nth cooperative TRP.

[0119] In step 716, the terminal may perform channel measurement (or estimation) for each of the CSI-RS received in step 714 and the CSI-RS received in step 715 (e.g., CSI-RS received from each of N cooperating TRPs). For example, the terminal may measure the received CSI-RS to obtain measurement values ​​for each channel for CSI reporting. At this time, the measurement value for each channel may further include at least one of a PMI for each TRP, one RI and CQI for cooperating transmission of the serving TRP and cooperating TRP, or additional information required for cooperating transmission. However, in the example described above, the composition of the information to be included in the CSI report may vary depending on whether the cooperating information is performed and the entity determining whether the cooperating information is performed (e.g., the terminal or the serving TRP).

[0120] In step 717, the terminal may transmit a CSI report containing the measurements from step 716 to the serving TRP. Therefore, unlike the description in FIGS. 4 and 5 above, the CSI report in step 717 may not include RI and CQI for all channels and may include additional information necessary for determining cooperative transmission.

[0121] The names of the periodic PMI-based DIV-JT procedures and each signaling are not limited to the examples above. Accordingly, at least one of the operations described above may be omitted, or at least one new operation may be added and performed in organic combination with the operations described above. Additionally, some of the operations described above may be combined into at least one operation or divided into two or more operations.

[0122] FIG. 8 illustrates a setup for performing PMI-based DIV-JT in a wireless communication system according to embodiments of the present disclosure.

[0123] Referring to FIG. 8, the configuration of configuration information for CSI reporting (e.g., the CSI-RS configuration of step 601 or step 701 described above) configured in a terminal to perform the PMI-based DIV-JT proposed in the present disclosure is described. Accordingly, the configuration information for CSI reporting may further include configuration information for cooperative transmission (e.g., JT transmission configuration). For example, the configuration information for CSI reporting of the terminal may include at least one additional information necessary to perform the cooperative transmission proposed in the present disclosure. For example, the at least one additional information may include information regarding whether PMI-based cooperative transmission is performed (e.g., reportMode), information for indicating the decision-maker for cooperative transmission (e.g., PMIJTConfig), or at least one of the information included in the CSI report according to the decision-maker for cooperative transmission. In this case, if it is not PMI-based cooperative transmission, it may mean that it operates as SU-MIMO. Alternatively, in the case of PMI-based cooperative transmission, the decision-making body for cooperative transmission may be set to a terminal (e.g., wDecision) and a serving TRP (e.g., woDecision).

[0124] In one embodiment, when a terminal decides to perform cooperative transmission, the terminal may report channel measurement results (e.g., at least one of PMI, RI, or CQI) to a serving TRP after deciding to perform cooperative transmission. At this time, the serving TRP may perform non-cooperative transmission (non-JT) or cooperative transmission according to the method determined by the terminal. The above-described non-cooperative transmission may refer to standalone transmission (e.g., SU-MIMO) by the serving TRP, rather than the PMI-based DIV-JT proposed in this disclosure.

[0125] In one embodiment, when the serving TRP determines cooperative transmission, the terminal may report to the serving TRP additional information necessary for the serving TRP to determine whether to cooperatively transmit and channel measurement results (e.g., at least one of PMI, RI, or CQI). At this time, the serving TRP may determine whether to cooperatively transmit (e.g., non-cooperative transmission or cooperative transmission) based on the information received from the terminal and perform data transmission (e.g., PDSCH) accordingly.

[0126] Meanwhile, as described above, the composition of information included in the CSI report may vary depending on the decision-making body for cooperative transmission, and the specific composition is explained below in Fig. 9.

[0127] FIG. 9 illustrates settings for performing PMI-based DIV-JT in a wireless communication system according to embodiments of the present disclosure.

[0128] Referring to FIG. 9, case (a) illustrates an example of configuration information when the terminal decides to perform PMI-based cooperative transmission. On the other hand, case (b) illustrates an example of configuration information when the serving TRP decides to perform PMI-based cooperative transmission.

[0129] In FIG. 9(a), when the terminal decides to perform PMI-based cooperative transmission based on the measurement results of CSI-RS received from the serving TRP and cooperative TRP, respectively (e.g., when reportMode is set (or indicated) to PMIJT and PMIJTReport in PMIJTConfig is set (or indicated) to wDecision), the overhead of the terminal's feedback transmission (e.g., CSI reporting) can be reduced, and the operation of the serving TRP can be simplified. More specifically, in (a), the terminal, through the multiple received CSI-RSs, [connects] one serving TRP and multiple (e.g., N, N 1) Channels of cooperative TRPs (e.g., The terminal can determine whether to cooperate based on ). In this case, the terminal can determine whether to cooperate based on the RSRP (reference signal received power) of the serving TRP and the cooperative TRP, the difference value of the RSRP between the serving TRP and the cooperative TRP, and the channels (e.g., Cooperative transmission can be determined based on channel correlation between ) or at least one of the principal angles between combinations of channels. After determining whether to cooperatively transmit, the terminal can perform channel measurements for data reception according to the determined method (e.g., calculating at least one of PMI, CQI, or RI). In this case, the information included in the CSI report is a 1-bit flag (e.g.,) for indicating whether to cooperatively transmit (or indicating cooperative or non-cooperative transmission). ) and information required for cooperative transmission (e.g., RI to be commonly used in serving TRP and cooperative TRP ( ) and CQI( ), and RI( PMI for each of the Serving TRP and Collaboration TRP determined according to ) ...including ) or information required for non-cooperative transmission (e.g., PMI for serving TRP( ), RI( ), and CQI( It may include ) including).

[0130] In FIG. 9(b), when the serving TRP decides to perform PMI-based cooperative transmission based on feedback from the terminal (e.g., when reportMode is set (or directed) to PMIJT and PMIJTReport within PMIJTConfig is set (or directed) to woDecision), the terminal may calculate additional metrics to enable the serving TRP to determine whether to perform cooperative transmission and transmit them to the serving TRP via CSI reporting. In the case of FIG. 9(b), a more accurate judgment may be possible in that the transmission method can be determined based on parameters that can be additionally considered only by the TRP (e.g., buffer occupancy (BO) status). However, quantification of CSI reporting may be necessary to reduce the feedback overhead caused by the terminal reporting additional information to the TRP to determine the transmission method. For example, the RSRP of the serving TRP and the cooperative TRP, and the difference value of the RSRP between the serving TRP and the cooperative TRP, may utilize the existing CSI reporting method. However, in the case of newly defined parameters, the terminal may construct a look-up table and report it to the serving TRP. More specifically, the information for the terminal to enable the serving TRP to determine whether to cooperate transmit in (b) includes the RSRP of the serving TRP and the cooperative TRP, the difference value of the RSRP between the serving TRP and the cooperative TRP, and the channels (e.g., It may include channel associations between, or at least one of the key angles between combinations of channels. In addition, the CSI report includes information necessary for cooperative transmission (e.g., RI to be commonly used in serving TRP and cooperative TRP ( ) and CQI( ), and RI( PMI for each of the Serving TRP and Collaboration TRP determined according to ) (including ) and information required for non-cooperative transmission (e.g., PMI for serving TRP( ), RI( ), and CQI( (including) may be included. In other words, for the serving TRP to determine whether to cooperatively transmit, the terminal may need to transmit both the information required for cooperative transmission and the information required for non-cooperative transmission to the serving TRP, unlike when the terminal determines whether to cooperatively transmit.

[0131] FIG. 10a illustrates an example of cooperative transmission in a wireless communication system according to embodiments of the present disclosure.

[0132] Referring to FIG. 10a, the operation of a serving TRP and at least one cooperating TRP according to the configuration of the CSI report of the terminal according to FIG. 9a described above is explained. The terminal has a 1-bit flag (e.g., to indicate to the serving TRP whether to cooperate transmit) ) and information required for cooperative transmission (e.g., RI to be commonly used in serving TRP and cooperative TRP ( ) and CQI( ), and RI( PMI for each of the Serving TRP and Collaboration TRP determined according to ) A CSI report including ) can be transmitted. In this case, a flag value indicating cooperative transmission may be set to 1, but this is merely an example and the flag value for cooperative transmission is not limited to 1. Additionally, the serving TRP can identify the transmission method (e.g., cooperative transmission) based on the information included in the CSI report. Furthermore, the serving TRP provides the information required by the cooperative TRP (e.g., RI ( ), PMI for each of at least one cooperative TRP( ), downlink data to be transmitted to the terminal ( ), or MCS to be used in at least one cooperative TRP ( It may transmit only (including at least one of ). In this case, the MCS can transmit the CQI reported by the terminal ( It can be determined based on ). Additionally, since the information described above transmitted from the serving TRP to the cooperating TRP may imply a cooperating transmission, additional flags indicating a cooperating transmission may not be included. Subsequently, the cooperating TRP can identify whether to perform a cooperating transmission based on the information received from the serving TRP. Accordingly, the cooperating TRP can transmit downlink data to the terminal using the PMI and MCS received from the serving TRP.

[0133] FIG. 10b illustrates the flow of signals in cooperative transmission in a wireless communication system according to embodiments of the present disclosure.

[0134] Referring to FIG. 10b, the flow of signals for cooperative transmission between the serving TRP and the cooperating TRP according to FIG. 10a described above is explained. Accordingly, the signalings illustrated in FIG. 10b may be the operations of the serving TRP and the cooperating TRP according to the configuration of the terminal's CSI report according to FIG. 9a described above. Additionally, descriptions that overlap with FIG. 10a may be omitted.

[0135] In step 1010, the terminal provides a 1-bit flag to indicate whether to cooperate transmit to the serving TRP (e.g., ) and information required for cooperative transmission (e.g., RI to be commonly used in serving TRP and cooperative TRP ( ) and CQI( ), and RI( PMI for each of the Serving TRP and Collaboration TRP determined according to ) A CSI report including ) can be transmitted.

[0136] In step 1020, the serving TRP identified as performing a cooperative transfer based on the information included in the CSI report provides the DU with the information necessary for the cooperative transfer (e.g., RI ( ), PMI for each of at least one cooperative TRP( ), downlink data to be transmitted to the terminal ( ), or MCS to be used in at least one cooperative TRP ( Only one of ) including at least one can be transmitted.

[0137] In step 1030, the DU can identify whether to perform cooperative transmission based on the information received in step 1020. Additionally, the DU can determine the precoder and MCS to use for cooperative transmission.

[0138] In step 1040, DU is the precoder determined in step 1030 ( ) and MCS, RI( ), and downlink data to be transmitted to the terminal ( ) can be sent to the serving TRP.

[0139] At step 1050, DU is the precoder determined at step 1030 ( ) and MCS, RI( ), and downlink data to be transmitted to the terminal ( ) can be transmitted to the cooperative TRP. However, the precoders used for cooperative transmission between the serving TRP and the cooperative TRP in steps 1040 and 1050 differ depending on each channel, but the MCS and RI( ) is a value that applies commonly to Serving TRP and Collaboration TRP and can be the same.

[0140] At step 1060, the serving TRP is the precoder received from the DU at step 1040 ( Downlink data using ) and MCS( ) can be transmitted to the terminal.

[0141] In step 1070, the cooperative TRP is the precoder received from the DU in step 1050 ( Downlink data using ) and MCS( ) can be transmitted to the terminal. Downlink data transmitted to the terminal in steps 1060 and 1070 ( ) can be the same data and can be transmitted using a single precoder and MCS.

[0142] The procedures and names of each signaling described above are not limited to the examples above. Accordingly, according to the description of FIG. 10a, at least one of the operations described above may be omitted, or at least one new operation may be added and performed in organic combination with the operations described above. Additionally, according to the description of FIG. 10a, some of the operations described above may be combined into at least one operation or divided into two or more operations.

[0143] FIG. 11a illustrates an example of non-cooperative transmission in a wireless communication system according to embodiments of the present disclosure.

[0144] Referring to FIG. 11a, the operation of a serving TRP and at least one cooperating TRP according to the configuration of the CSI report of the terminal according to FIG. 9a described above is explained. The terminal has a 1-bit flag (e.g., to indicate to the serving TRP whether to cooperate transmit) ) and information required for non-cooperative transmission (e.g., PMI for serving TRP( ), RI( ), and CQI( A CSI report including ) can be transmitted. In this case, a flag value indicating a non-cooperative transmission may be set to 0, but this is merely an example and the flag value indicating a non-cooperative transmission is not limited to 0. Additionally, the serving TRP can identify the transmission method (e.g., non-cooperative transmission) based on the information contained in the CSI report. Furthermore, the serving TRP may use a flag to indicate to the cooperating TRP that a non-cooperative transmission will be performed (e.g., ) can be transmitted. Accordingly, the cooperative TRP can identify that a non-cooperative transmission will be performed. Therefore, only the serving TRP can transmit downlink data to the terminal based on the information received from the terminal.

[0145] FIG. 11b illustrates the flow of signals in non-cooperative transmission in a wireless communication system according to embodiments of the present disclosure.

[0146] Referring to FIG. 11b, the flow of signals for cooperative transmission between the serving TRP and the cooperating TRP according to FIG. 10a described above is explained. Accordingly, the signalings illustrated in FIG. 11b may be the operations of the serving TRP and the cooperating TRP according to the configuration of the terminal's CSI report according to FIG. 9a described above. Additionally, descriptions that overlap with FIG. 11a may be omitted.

[0147] In step 1110, the terminal provides a 1-bit flag to indicate whether to cooperate transmit to the serving TRP (e.g., ) and information required for non-cooperative transmission (e.g., PMI for serving TRP( ), RI( ), and CQI( A CSI report including ) can be transmitted.

[0148] In step 1120, the serving TRP identified as performing a non-cooperative transfer based on the information included in the CSI report provides the information required by the DU (e.g., a flag indicating a non-cooperative transfer (e.g., ) and information required for non-cooperative transmission (e.g., PMI for serving TRP( ), RI( ), and CQI( Only ) including )) can be transmitted.

[0149] In step 1130, the DU can identify whether to perform a non-cooperative transmission based on the information received in step 1120. Additionally, the DU can determine the precoder and MCS that the serving TRP will use for downlink transmission.

[0150] In step 1140, DU is the precoder determined in step 1130 ( ) and MCS, RI of Serving TRP( ), and downlink data to be transmitted to the terminal ( ) can be sent to the serving TRP.

[0151] In step 1150, the DU has a flag indicating non-cooperative transmission (e.g., ) can be transmitted to the cooperative TRP. By doing so, the cooperative TRP can identify that there is no need to perform cooperative transmission and may not perform downlink transmission to the terminal thereafter.

[0152] At step 1160, the serving TRP is the precoder received from the DU at step 1040 ( Downlink data using ) and MCS( ) can be transmitted to the terminal.

[0153] The procedures and names of each signaling described above are not limited to the examples above. Accordingly, as described in FIG. 11a, at least one of the described operations may be omitted, or at least one new operation may be added and performed in organic combination with the described operations. Additionally, as described in FIG. 11a, some of the described operations may be combined into at least one operation or divided into two or more operations.

[0154] FIG. 12 illustrates the flow of signals for stopping cooperative transmission in a wireless communication system according to embodiments of the present disclosure.

[0155] Referring to FIG. 12, even after cooperative transmission by a serving TRP and at least one cooperative TRP has been triggered according to the embodiments described above, the serving TRP may stop cooperative transmission if there is no throughput gain (T_put gain) from cooperative transmission or if it is below a certain level.

[0156] In step 1210, the terminal (e.g., CoMP UE) may receive downlink data from the serving TRP and, whenever downlink data is received, may transmit feedback (e.g., HARQ (hybrid automatic repeat and request) feedback) for the reception of each downlink data to the serving TRP. At this time, the transmission of downlink data may follow a standalone transmission method (e.g., SU-MIMO) from the serving TRP rather than the cooperative transmission method proposed in this disclosure. Meanwhile, when the serving TRP transmits downlink data in a non-cooperative transmission manner (e.g., when transmitting downlink data before the setup for cooperative transmission (e.g., step 601, step 611, step 701, or step 711)), the MCS, layer, and HARQ feedback (e.g., HARQ ACK (acknowledgement) or HARQ NACK (not-acknowledgement)) used for downlink transmission can be collected using a sliding window method (e.g., moving a window of fixed size and collecting information related to downlink transmission within that window).

[0157] In step 1220, the DU can transmit configuration information for cooperative transmission to the serving TRP, and the serving TRP can transmit the configuration information received from the DU to the terminal (e.g., step 601, step 611, step 701, or step 711).

[0158] In step 1230, the DU may transmit control information (e.g., DCI) to the serving TRP, at least one cooperating TRP, and the terminal to initiate a cooperating transmission according to the embodiments described above (e.g., steps 602, 612, 702, or 712). Subsequently, a cooperating transmission according to the embodiments proposed in this disclosure may be triggered.

[0159] In step 1240, the terminal may receive the same downlink data from the serving TRP and at least one cooperating TRP based on steps 1220 and 1230. The terminal may then transmit feedback (e.g., HARQ ACK or HARQ NACK) for the reception of each downlink data to the serving TRP. Meanwhile, the serving TRP may collect the MCS, layer, and HARQ feedback used for downlink transmission in a sliding window manner.

[0160] At step 1250, the DU may decide whether to continue the cooperative transmission. For example, if the throughput of the non-cooperative transmission based on the information collected at step 1210 is greater than (or greater than or equal to) the throughput of the cooperative transmission based on the information collected at step 1240, or if there is no gain in throughput, the DU may decide to stop the cooperative transmission.

[0161] In step 1260, the DU may transmit control information (e.g., DCI) to stop cooperative transmission to a serving TRP, at least one cooperative TRP, and a terminal.

[0162] In step 1270, the DU may transmit configuration information for non-cooperative transmission to the serving TRP, and the serving TRP may transmit the configuration information received from the DU to the terminal. At this time, the configuration information may include a 1-bit flag to indicate the discontinuation of cooperative transmission. Alternatively, the configuration information may include separate configuration information for the serving TRP's standalone transmission (e.g., SU-MIMO).

[0163] Meanwhile, it goes without saying that even after cooperative transmission has been interrupted, cooperative transmission according to the embodiments described above may be resumed based on feedback information from the terminal if necessary. Additionally, although the embodiment of FIG. 12 described above explains a method in which the interruption of cooperative transmission is determined by a serving TRP (e.g., DU), in another embodiment, the procedure for interrupting cooperative transmission may be performed by the terminal deciding to interrupt cooperative transmission based on information collected in steps 1210 and 1240 and notifying the serving TRP.

[0164] The procedures and names of each signaling described above are not limited to the examples above. Accordingly, at least one of the described operations may be omitted, or at least one new operation may be added and performed in organic combination with the described operations. Additionally, some of the described operations may be combined into at least one operation or divided into two or more operations.

[0165] FIG. 13 illustrates the operation of a terminal for performing a PMI-based DIV-JT technique in a wireless communication system according to embodiments of the present disclosure.

[0166] Referring to FIG. 13, the operation of a terminal (e.g., CoMP UE) proposed in the present disclosure is illustrated, and some or all of the various embodiments related to cooperative transmission described above may be applied to FIG. 13 in the same or similar manner.

[0167] In step 1310, the terminal may receive configuration information regarding PMI-based cooperative transmission from the first base station. At this time, the first base station may refer to the first base station connected to the terminal. Additionally, the configuration information regarding PMI-based cooperative transmission may include information for instructing the terminal to report additional information required for cooperative transmission based on CSI-RS, and may be included in the configuration information for the terminal's CSI reporting. Furthermore, the terminal may receive control information for initiating cooperative transmission from the first base station.

[0168] In step 1320, the terminal can receive a first CSI-RS from the first base station based on configuration information. At this time, the reception of the first CSI-RS may be performed non-periodically or periodically based on the configuration information of step 1310.

[0169] In step 1330, the terminal may receive a second CSI-RS from a second base station based on configuration information. At this time, the second base station may refer to a second base station that is not connected to the terminal but performs cooperative transmission to the terminal together with the first base station. The second CSI-RS transmission may be performed non-periodically or periodically based on the configuration information of step 1310. Additionally, the second CSI-RS transmission may be initiated based on control information indicating the timing of the second CSI-RS transmission received from the first base station.

[0170] In step 1340, the terminal may transmit a CSI report to the first base station that includes measurement results for the first CSI-RS and the second CSI-RS, respectively, and information related to the cooperative transmission. In one embodiment, the terminal may decide to perform PMI-based cooperative transmission based on the measurement results of the CSI-RS received from the first base station and the second base station, respectively. In this case, the information included in the CSI report may include a 1-bit flag for indicating whether to perform cooperative transmission and information required for cooperative transmission (e.g., including RI and CQI to be used commonly at the first base station and the second base station, and PMI for the first base station and the second base station, respectively, determined according to the RI) or information required for non-cooperative transmission (e.g., including PMI, RI, and CQI for the first base station). In another embodiment, the first base station may decide to perform PMI-based cooperative transmission based on the information included in the CSI report received from the terminal. At this time, the CSI report may include information for determining whether the first base station is cooperatively transmitting and information required depending on whether cooperative transmission is performed. For example, the information for determining whether cooperative transmission is performed may include at least one of the RSRP of the first base station and the second base station, the difference value of the RSRP between the first base station and the second base station, channel association between channels, or the major angle between combinations of channels. Additionally, the information required depending on whether cooperative transmission is performed may include information required for cooperative transmission (e.g., RI and CQI to be commonly used at the first base station and the second base station, and PMI for each of the first base station and the second base station determined according to the RI) and information required for non-cooperative transmission (e.g., PMI, RI, and CQI for the first base station).

[0171] Meanwhile, although an embodiment of the operation of the terminal has been described above based on the flowchart shown in FIG. 13, it is obvious that the operation of the terminal may vary according to other embodiments described above.

[0172] FIG. 14 illustrates the operation of a terminal for performing a PMI-based DIV-JT technique in a wireless communication system according to embodiments of the present disclosure.

[0173] Referring to FIG. 14, the operation of a base station proposed in the present disclosure is illustrated, and some or all of the various embodiments related to cooperative transmission described above may be applied in the same or similar way to FIG. 14.

[0174] In step 1410, the first base station may transmit configuration information regarding PMI-based cooperative transmission to a terminal (e.g., CoMP UE). In this case, the first base station may refer to the first base station connected to the terminal. Additionally, the configuration information regarding PMI-based cooperative transmission may include information for instructing the terminal to report additional information required for cooperative transmission based on CSI-RS, and may be included in the configuration information for the terminal's CSI reporting. Furthermore, the first base station may transmit control information for initiating cooperative transmission to the terminal.

[0175] In step 1420, the first base station may transmit configuration information to the second base station. Here, the second base station may refer to a second base station that is not connected to the terminal but performs cooperative transmission to the terminal together with the first base station. For example, the first base station may also transmit configuration information for CSI reporting transmitted to the terminal to the second base station. Here, the configuration information for CSI reporting may be transmitted via the DU. As another example, the configuration information transmitted to the second base station may not include configuration information for cooperative transmission transmitted to the terminal (e.g., information to instruct the terminal to report additional information required for cooperative transmission based on CSI-RS).

[0176] In step 1430, the first base station may transmit the first CSI-RS to the terminal based on the configuration information. At this time, the transmission of the first CSI-RS may be performed non-periodically or periodically based on the configuration information of step 1410.

[0177] In step 1440, the first base station may receive a CSI report from the terminal containing measurement results for each of the first CSI-RS and the second CSI-RS and information related to cooperative transmission. In one embodiment, when the terminal decides to perform PMI-based cooperative transmission, the information included in the CSI report may include a 1-bit flag for indicating whether to perform cooperative transmission and information required for cooperative transmission (e.g., RI and CQI to be used commonly at the first base station and the second base station, and PMI for each of the first base station and the second base station determined according to the RI) or information required for non-cooperative transmission (e.g., PMI, RI, and CQI for the first base station). In another embodiment, when the first base station decides to perform PMI-based cooperative transmission, the CSI report may include information for the first base station to determine whether to perform cooperative transmission and information required depending on whether to perform cooperative transmission. For example, information for determining whether to perform cooperative transmission may include at least one of the RSRP of the first base station and the second base station, the difference value of the RSRP between the first base station and the second base station, channel association between channels, or a major angle between combinations of channels. Additionally, information required depending on whether to perform cooperative transmission may include information required for cooperative transmission (e.g., RI and CQI to be commonly used at the first base station and the second base station, and PMI for each of the first base station and the second base station determined according to the RI) and information required for non-cooperative transmission (e.g., PMI, RI, and CQI for the first base station).

[0178] Meanwhile, although an embodiment of the operation of a base station has been described above based on the flowchart shown in FIG. 14, it is obvious that the operation of the base station may vary according to other embodiments described above.

[0179] Methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0180] When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of this disclosure.

[0181] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disc storage devices, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0182] Additionally, the program may be stored on an attachable storage device that can be accessed via a communication network such as the Internet, Intranet, LAN (local area network), WAN (wide area network), or SAN (storage area network), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. Additionally, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

[0183] In the specific embodiments of the present disclosure described above, the components included in the disclosure are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed of a singular form, and even if a component is expressed in the singular form, it may be composed of a plural form.

[0184] Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, it is understood that various modifications are possible within the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof.

Claims

1. A method performed by a terminal of a wireless communication system, A step of receiving configuration information regarding joint transmission based on PMI (precoding matrix indicator) from a first base station; A step of receiving a first CSI (channel state information)-RS (reference signal) from the first base station based on the setting information; A step of receiving a second CSI-RS from a second base station based on the setting information; and The method includes the step of transmitting a CSI report to the first base station, the report including measurement results for each of the first CSI-RS and the second CSI-RS and information related to the cooperative transmission. A method wherein the above cooperative transmission includes the transmission of the same data from each of the first base station and the second base station to the terminal supporting CoMP (coordinated multi-point operation).

2. In paragraph 1, the above method is, The method further includes the step of receiving information regarding the start time of the cooperative transmission from the first base station based on the setting information, and A method in which the above setting information includes at least one of information regarding the type of the cooperative transmission or information regarding the reporting type of the cooperative transmission.

3. In paragraph 1, the above method is, The method further includes the step of determining the cooperative transmission based on a first channel with the first base station and a second channel with the second base station, A method in which the information related to the above-mentioned cooperation transmission includes instruction information regarding whether the above-mentioned cooperation transmission is performed.

4. In Paragraph 1, The above cooperative transmission is based on information related to the above cooperative transmission, and A method in which the information related to the above cooperative transmission includes at least one of information regarding buffer occupancy, a first RSRP (reference signal received power) for the first base station, a second RSRP for the second base station, or a difference value between the first RSRP and the second RSRP.

5. A method performed by a first base station of a wireless communication system, A step of transmitting configuration information regarding joint transmission based on PMI (precoding matrix indicator) to a terminal; A step of transmitting the above-mentioned setting information to a second base station; A step of transmitting a first CSI (channel state information) RS (reference signal) to the terminal based on the setting information; and The method includes the step of receiving a CSI report from the terminal, the report including measurement results for each of the first CSI-RS and the second CSI-RS and information related to the cooperative transmission. The above second CSI-RS is transmitted from the second base station to the terminal based on the above setting information, and A method wherein the above cooperative transmission includes the transmission of the same data from each of the first base station and the second base station to the terminal supporting CoMP (coordinated multi-point operation).

6. In paragraph 5, the above method is, The method further includes the step of transmitting information regarding the start time of the cooperative transmission to the above terminal based on the above setting information, and A method in which the above setting information includes at least one of information regarding the type of the cooperative transmission or information regarding the reporting type of the cooperative transmission.

7. In Paragraph 5, The above cooperative transmission is determined based on the first channel with the first base station and the second channel with the second base station, and A method in which the information related to the above-mentioned cooperation transmission includes instruction information regarding whether the above-mentioned cooperation transmission is performed.

8. In paragraph 5, the above method is, It further includes a step of determining the cooperative transmission based on information related to the cooperative transmission, A method in which the information related to the above cooperative transmission includes at least one of information regarding buffer occupancy, a first RSRP (reference signal received power) for the first base station, a second RSRP for the second base station, or a difference value between the first RSRP and the second RSRP.

9. In a terminal of a wireless communication system, Transmitter / receiver; and It includes at least one control unit connected to the above-mentioned transmitting and receiving unit, and The above at least one control unit is: Receive configuration information regarding joint transmission based on PMI (precoding matrix indicator) from the first base station, and From the first base station, a first CSI (channel state information) RS (reference signal) is received based on the setting information, and From the second base station, receiving the second CSI-RS based on the above-mentioned configuration information, and The first base station is configured to transmit a CSI report including measurement results for each of the first CSI-RS and the second CSI-RS and information related to the cooperative transmission, and The above cooperative transmission includes the transmission of the same data from each of the first base station and the second base station to the terminal that supports CoMP (coordinated multi-point operation).

10. In paragraph 9, the at least one control unit is: It is further configured to receive information regarding the start time of the cooperative transmission from the first base station based on the setting information, and A terminal in which the above setting information includes at least one of information regarding the type of the cooperative transmission or information regarding the reporting type of the cooperative transmission.

11. In paragraph 9, the at least one control unit is: It is further configured to determine the cooperative transmission based on the first channel with the first base station and the second channel with the second base station, and A terminal in which the information related to the above cooperative transmission includes instruction information regarding whether the above cooperative transmission is performed.

12. In Paragraph 9, The above cooperative transmission is based on information related to the above cooperative transmission, and A terminal comprising at least one of the information regarding the above cooperative transmission, the first RSRP (reference signal received power) for the first base station, the second RSRP for the second base station, or the difference value between the first RSRP and the second RSRP.

13. In the first base station of a wireless communication system, Transmitter / receiver; and It includes at least one control unit connected to the above-mentioned transmitting and receiving unit, and The above at least one control unit is: Transmit configuration information regarding PMI (precoding matrix indicator)-based joint transmission to the terminal, and Transmit the above setting information to the second base station, and To the above terminal, a first CSI (channel state information) RS (reference signal) is transmitted based on the above setting information, and, The above terminal is configured to receive a CSI report including measurement results for each of the first CSI-RS and the second CSI-RS and information related to the cooperative transmission, and The above second CSI-RS is transmitted from the second base station to the terminal based on the above setting information, and The above cooperative transmission includes the transmission of the same data from each of the first base station and the second base station to the terminal supporting CoMP (coordinated multi-point operation), the first base station.

14. In paragraph 13, the above at least one control unit is: The above terminal is further configured to transmit information regarding the start time of the cooperation transmission based on the above setting information, and A first base station, wherein the above setting information includes at least one of information regarding the type of the cooperative transmission or information regarding the reporting type of the cooperative transmission.

15. In Paragraph 13, The above cooperative transmission is determined based on the first channel with the first base station and the second channel with the second base station, and A first base station in which the information related to the above cooperative transmission includes instruction information regarding whether the above cooperative transmission is performed.

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