Apparatus and method for reporting partial channel state information (CSI) in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for providing a higher data transmission rate than the previous 4G communication system, such as LTE. A method performed by a user equipment (UE) in a wireless communication system according to various embodiments of the present disclosure may comprise the steps of: receiving first information for configuring a first channel state information (CSI) report related to some of antenna ports of a base station from a base station; receiving a reference signal (CSI-RS) from the base station; and transmitting the first CSI report to the base station on the basis of the first information, wherein the first CSI report may include a value obtained on the basis of a second CSI report related to all of the antenna ports of the base station.

Description

In a wireless communication system, a device and method for reporting PARTIAL PORT CSI (CHANNEL STATE INFORMATION)

[0001] The present disclosure relates generally to a wireless communication system, and more particularly, to an apparatus and method for efficiently transmitting and receiving partial port CSI (channel state information) between a base station and a terminal.

[0002] Looking back at the evolution of wireless communication over successive generations, technologies have primarily been developed for human-facing services such as voice, multimedia, and data. With the commercialization of the 5G (5th Generation) communication system, an explosive increase in connected devices is 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 equipment, and factory equipment. Mobile devices are also expected to evolve into diverse form factors, such as augmented reality glasses, virtual reality headsets, and holographic devices. In the 6G (6th Generation) era, efforts are being made to develop improved 6G communication systems to connect hundreds of billions of devices and objects and provide diverse services. For this reason, 6G communication systems are often referred to as "beyond 5G."

[0003] The 6G communication system, expected to be realized around 2030, will have a maximum transmission speed of terabytes (i.e., 1,000 gigabits) per second (bps) and a wireless latency of 100 microseconds (μsec). In other words, compared to 5G, the transmission speed in a 6G communication system will be 50 times faster and the wireless latency will be reduced to one-tenth.

[0004] To achieve these high data rates and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz (THz) band (e.g., from 95 gigahertz (GHz) to 3 terahertz (THz)). Compared to the millimeter wave (mmWave) band introduced in 5G, the terahertz band is expected to have more severe path loss and atmospheric absorption, making it more important to develop technologies that can guarantee signal reach, or coverage. Key technologies to ensure coverage include Radio Frequency (RF) components, antennas, new waveforms that offer better coverage than Orthogonal Frequency Division Multiplexing (OFDM), beamforming, and multiple antenna transmission technologies such as massive Multiple-Input and Multiple-Output (MIMO), Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing using Orbital Angular Momentum (OAM), and Reconfigurable Intelligent Surface (RIS) are being discussed to improve the coverage of terahertz band signals.

[0005] In addition, in order to improve frequency efficiency and system network, 6G communication systems are developing full duplex technology that utilizes the same frequency resources at the same time for uplink and downlink; network technology that integrates satellites and HAPS (High-Altitude Platform Stations); network structure innovation technology that supports mobile base stations and enables optimization and automation of network operation; 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 with complexity that exceeds the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources (Mobile Edge Computing (MEC), cloud, etc.). In addition, efforts are being made to further strengthen connectivity between devices, further optimize networks, promote softwareization of network entities, and increase the openness of wireless communications through the design of new protocols to be used in 6G communication systems, the implementation of hardware-based security environments, the development of mechanisms for the safe use of data, and the development of technologies for maintaining privacy.

[0006] Research and development of these 6G communication systems are expected to enable a new level of hyper-connected experience through the hyper-connectivity of 6G communication systems, which encompass not only connections between things but also connections between people and things. Specifically, 6G communication systems are expected to enable 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 through enhanced security and reliability, will be applied in diverse fields such as industry, medicine, automobiles, and home appliances.

[0007] In a wireless communication system, a terminal can receive downlink or transmit uplink based on resource settings configured by a base station. In addition to the typical frequency division duplex (FDD) and time division duplex (TDD) methods, cross division duplex (XDD) can be used to transmit uplink and downlink signals between the base station and the terminal. In an XDD system, an operational method is required to increase transmission efficiency by configuring channel state information (CSI) and CSI reporting for some of the antenna ports.

[0008] Based on the discussion described above, the present disclosure seeks to provide a device and method capable of performing effective signal transmission and reception in a wireless communication system.

[0009] More specifically, in a cross division duplex (XDD) system, a device and method for efficiently transmitting and receiving signals between a base station and a terminal by setting channel state information (CSI) and reporting of CSI for some antenna ports are provided.

[0010] According to various embodiments of the present disclosure, in a wireless communication system, a method performed by a user equipment (UE) includes the steps of: receiving, from a base station, first information for setting a first channel state information (CSI) report associated with some of antenna ports of the base station; receiving, from the base station, a CSI-RS (reference signal); and transmitting, to the base station, the first CSI report based on the first information, wherein the first CSI report may include a value obtained based on a second CSI report associated with all of the antenna ports of the base station.

[0011] According to various embodiments of the present disclosure, a method includes transmitting, to a user equipment (UE), first information for setting a first channel state information (CSI) report associated with some of antenna ports of the base station, transmitting, to the UE, a CSI-RS (reference signal), and receiving, from the UE, the first CSI report based on the first information, wherein the first CSI report may include a value obtained based on a second CSI report associated with all of the antenna ports of the base station.

[0012] According to various embodiments of the present disclosure, in a wireless communication system, a user equipment (UE) may include a transceiver and a controller coupled to the transceiver, wherein the controller may be configured to receive, from a base station, first information configuring a first channel state information (CSI) report associated with some of antenna ports of the base station, receive, from the base station, a CSI-RS (reference signal), and transmit the first CSI report to the base station based on the first information, wherein the first CSI report may include a value obtained based on a second CSI report associated with all of the antenna ports of the base station.

[0013] According to various embodiments of the present disclosure, in a wireless communication system, a base station may include a transceiver and a controller coupled to the transceiver, wherein the controller may be configured to transmit, to a user equipment (UE), first information setting a first channel state information (CSI) report associated with some of antenna ports of the base station, transmit a CSI-RS (reference signal) to the UE, and receive, from the UE, the first CSI report based on the first information, wherein the first CSI report may include a value obtained based on a second CSI report associated with all of the antenna ports of the base station.

[0014] The present disclosure provides a device and method capable of effectively providing a service in a wireless communication system.

[0015] The present disclosure provides a device and method capable of performing effective signal transmission and reception in a wireless communication system.

[0016] The effects that can be obtained from the present disclosure are not limited to the effects mentioned in the various embodiments, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0017] FIG. 1 illustrates a wireless environment network in a wireless communication system according to various embodiments of the present disclosure.

[0018] FIG. 2 illustrates a functional configuration of a base station in a wireless communication system according to various embodiments of the present disclosure.

[0019] FIG. 3 illustrates a functional configuration of a terminal in a wireless communication system according to various embodiments of the present disclosure.

[0020] FIG. 4 illustrates an example of a wireless resource region in a wireless communication system according to various embodiments of the present disclosure.

[0021] FIG. 5 illustrates examples of antenna ports used per slot in a cross division duplex (XDD) system according to various embodiments of the present disclosure.

[0022] FIG. 6 illustrates an example for reporting channel state information (CSI) in an XDD system according to various embodiments of the present disclosure.

[0023] FIG. 7 illustrates an example for transmitting a partial port CSI-RS (channel state information-reference signal) in an XDD system according to various embodiments of the present disclosure.

[0024] FIG. 8 illustrates an example of an antenna port for partial port CSI reporting in an XDD system according to various embodiments of the present disclosure.

[0025] FIG. 9 illustrates an example of information for reporting partial port CSI according to various embodiments of the present disclosure.

[0026] FIGS. 10A and 10B illustrate the number of bits required to report partial port CSI according to various embodiments of the present disclosure.

[0027] The terms used in this disclosure are used only to describe specific embodiments and may not be intended to limit the scope of other embodiments. The singular expression may include the plural expression unless the context clearly indicates otherwise. Terms used, including technical or scientific terms, may have the same meaning as commonly understood by those of ordinary skill in the art described in this disclosure. Terms used in this disclosure that are defined in general dictionaries may be interpreted as having the same or similar meaning as the meaning they have in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this disclosure. In some cases, even if a term is defined in this disclosure, it cannot be interpreted to exclude embodiments of the present disclosure.

[0028] The various embodiments of the present disclosure described below illustrate hardware-based approaches. However, since the various embodiments of the present disclosure include technologies utilizing both hardware and software, the various embodiments of the present disclosure do not exclude software-based approaches. Furthermore, terms referring to network entities, terms referring to device components, and the like are provided for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms with equivalent technical meanings may be used.

[0029] Additionally, although this disclosure describes various embodiments using terms defined by certain communication standards (e.g., 3rd generation partnership project (3GPP) and European Telecommunication Standards Institute (ETSI)), these are merely illustrative examples. The various embodiments of this disclosure can be easily modified and applied to other communication systems.

[0030] Additionally, in the present disclosure, expressions such as "more than" or "less than" may be used to determine whether a specific condition is satisfied or fulfilled. However, this is merely a description for expressing an example and does not exclude descriptions of more than or less than. Conditions described as "more than" may be replaced with "more than," conditions described as "less than" may be replaced with "less than," and conditions described as "more than and less than" may be replaced with "more than and less than."

[0031] The terms used in the following description, including terms referring to signals, channels, control information, network entities, and device components, are provided for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms with equivalent technical meanings may be used.

[0032] FIG. 1 illustrates a wireless environment network in a wireless communication system according to various embodiments of the present disclosure. FIG. 1 illustrates a base station (110), a first terminal (120), and a second terminal (130) as some of the nodes utilizing a wireless channel in the wireless communication system. While FIG. 1 illustrates only one base station, other base stations identical to or similar to the base station (110) may be included.

[0033] The 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 a signal can be transmitted. In addition to the base station, the base station (110) may be referred to as an 'access point (AP)', 'eNodeB (eNB)', '5th generation node', 'next generation nodeB (gNB)', 'wireless point', 'transmission / reception point (TRP)', or other terms having equivalent technical meanings.

[0034] Each of the first terminal (120) and the second terminal (130) is a device used by a user and communicates with the base station (110) via a wireless channel. In some cases, at least one of the first terminal (120) and the second terminal (130) may be operated without the involvement of the user. That is, at least one of the first terminal (120) and the second terminal (130) is a device that performs machine type communication (MTC) and may not be carried by the user. Each of the first terminal (120) and the second terminal (130) may be referred to as a 'user equipment (UE)', a 'mobile station', a 'subscriber station', a 'remote terminal', a 'wireless terminal', a 'user device', or other terms having an equivalent technical meaning thereto.

[0035] The base station (110), the first terminal (120), and the second terminal (130) can transmit and receive wireless signals in a millimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 38 GHz, 60 GHz). At this time, in order to improve channel gain, the base station (110), the first terminal (120), and the second terminal (130) can perform beamforming. Here, the beamforming can include transmission beamforming and reception beamforming. That is, the base station (110), the first terminal (120), and the second terminal (130) can provide directionality to a transmission signal or a reception signal. To this end, the base station (110) and the terminals (120, 130) can select serving beams through a beam search or beam management procedure. After serving beams are selected, subsequent communications can be performed through resources that are in a quasi-co-located (QCL) relationship with the resource that transmitted the serving beams.

[0036] If large-scale characteristics of a channel carrying a symbol on a first antenna port can be inferred from a channel carrying a symbol on a second antenna port, the first antenna port and the second antenna port can be evaluated to have a QCL relationship. For example, the large-scale characteristics may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and a spatial receiver parameter.

[0037] FIG. 2 illustrates the functional configuration of a base station in a wireless communication system according to various embodiments of the present disclosure. The configuration illustrated in FIG. 2 may be understood as the configuration of a base station (110). Terms such as "... unit" and "... unit" used hereinafter refer to a unit that processes at least one function or operation, which may be implemented using hardware, software, or a combination of hardware and software.

[0038] Referring to FIG. 2, the base station includes a wireless communication unit (210), a backhaul communication unit (220), a storage unit (230), and a control unit (240).

[0039] The wireless communication unit (210) performs functions for transmitting and receiving signals via a wireless channel. For example, the wireless communication unit (210) performs a conversion function between baseband signals and bit streams according to the physical layer specifications of the system. For example, when transmitting data, the wireless communication unit (210) encodes and modulates the transmitted bit stream to generate complex symbols. Additionally, when receiving data, the wireless communication unit (210) restores the received bit stream by demodulating and decoding the baseband signal.

[0040] In addition, the wireless communication unit (210) upconverts a baseband signal into an RF (radio frequency) band signal and transmits it through an antenna, and downconverts an RF band signal received through the antenna into a baseband signal. To this end, the wireless communication unit (210) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc. In addition, the wireless communication unit (210) may include a plurality of transmission and reception paths. Furthermore, the wireless communication unit (210) may include at least one antenna array composed of a plurality of antenna elements.

[0041] 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. The digital unit may be implemented with at least one processor (e.g., a digital signal processor (DSP)).

[0042] 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 "transceiver." Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean that the wireless communication unit (210) performs the processing described above.

[0043] 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 string transmitted from a base station to another node, such as another access node, another base station, an upper node, a core network, etc., into a physical signal, and converts a physical signal received from another node into a bit string.

[0044] The storage unit (230) stores data such as basic programs, application programs, and setting information for the operation of the base station. The storage unit (230) may be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. In addition, the storage unit (230) provides stored data upon request from the control unit (240).

[0045] The control unit (240) (e.g., the controller) controls the overall operations of the base station. For example, the control unit (240) transmits and receives signals through the wireless communication unit (210) or through the backhaul communication unit (220). In addition, the control unit (240) records and reads data in the storage unit (230). In addition, the control unit (240) can perform functions of a protocol stack required by a communication standard. According to another implementation example, the protocol stack can be included in the wireless communication unit (210). To this end, the control unit (240) can include at least one processor.

[0046] According to various embodiments, the control unit (240) can control the base station to perform operations according to various embodiments described below.

[0047] FIG. 3 illustrates the functional configuration of a terminal in a wireless communication system according to various embodiments of the present disclosure. The configuration illustrated in FIG. 3 may be understood as the configuration of terminals (120, 130). Terms such as "... unit" and "... unit" used hereinafter refer to a unit that processes at least one function or operation, which may be implemented using hardware, software, or a combination of hardware and software.

[0048] Referring to FIG. 3, the terminal includes a communication unit (310), a storage unit (320), and a control unit (330).

[0049] The communication unit (310) performs functions for transmitting and receiving signals via a wireless channel. For example, the communication unit (310) performs a conversion function between a baseband signal and a bit stream 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 a transmission bit stream. In addition, when receiving data, the communication unit (310) restores a reception bit stream by demodulating and decoding the baseband signal. In addition, the communication unit (310) upconverts a baseband signal to an RF band signal and transmits it through an antenna, and downconverts an RF band signal received through the antenna to 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.

[0050] In addition, 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 digital circuits and analog circuits (e.g., radio frequency integrated circuits (RFIC)). Here, the digital circuits and analog circuits may be implemented in a single package. In addition, the communication unit (310) may include a plurality of RF chains. Furthermore, the communication unit (310) may perform beamforming.

[0051] 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 "transmitting and receiving unit." Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean processing performed by the communication unit (310) as described above.

[0052] 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 and non-volatile memory. In addition, the storage unit (320) provides stored data upon request from the control unit (330).

[0053] The control unit (330) (e.g., controller) controls the overall operations of the terminal. For example, the control unit (330) transmits and receives signals through the communication unit (310). In addition, the control unit (330) records and reads data in the storage unit (320). In addition, 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 may be a part of a processor. In addition, a part of the communication unit (310) and the control unit (330) may be referred to as a CP (communication processor).

[0054] According to various embodiments, the control unit (330) can control the terminal to perform operations according to various embodiments described below.

[0055] FIG. 4 illustrates an example of a wireless resource region in a wireless communication system according to various embodiments of the present disclosure. In various embodiments of the present disclosure, the wireless resource region may include a structure in the time-frequency domain. In one embodiment, the wireless communication system may include an NR communication system.

[0056] Referring to FIG. 4, in the wireless resource domain, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The length of a radio frame (404) is 10 ms. The radio frame (404) may be a time domain section composed of 10 subframes. The length of a subframe (403) is 1 ms. The unit of configuration in the time domain may be an orthogonal frequency division multiplexing (OFDM) and / or a DFT-s-OFDM (DFT (discrete Fourier transform)-spread-OFDM) symbol, and Nsymb OFDM and / or DFT-s-OFDM symbols (401) may be gathered to form one slot (402). In various embodiments, the OFDM symbol may include a symbol for transmitting and receiving a signal using an OFDM multiplexing scheme, and the DFT-s-OFDM symbol may include a symbol for transmitting and receiving a signal using a DFT-s-OFDM or SC-FDMA (single carrier frequency division multiple access) multiplexing scheme. The minimum transmission unit in the frequency domain is a subcarrier, and the carrier bandwidth constituting the resource grid may be composed of a total of NscBW subcarriers (405). In addition, in the present disclosure, for the convenience of explanation, an embodiment regarding downlink signal transmission and reception is described, but this can also be applied to an embodiment regarding uplink signal transmission and reception.

[0057] In some embodiments, the number of slots (402) constituting one subframe (403) and the length of the slots (402) may vary depending on the subcarrier spacing. This subcarrier spacing may be referred to as a numerology (μ). That is, the subcarrier spacing, the number of slots included in a subframe, the length of the slots, and the length of the subframe may be configured variably. For example, in an NR communication system, when the subcarrier spacing (SCS) is 15 kHz, one slot (402) constitutes one subframe (403), and the lengths of the slot (402) and the subframe (403) may each be 1 ms. In addition, for example, when the subcarrier spacing is 30 kHz, two slots may constitute one subframe (403). In this case, the length of the slot is 0.5 ms and the length of the subframe is 1 ms.

[0058] In some embodiments, the subcarrier spacing, the number of slots included in a subframe, the length of the slot, and the length of the subframe may be applied variably depending on the communication system. For example, in the case of an LTE system, the subcarrier spacing may be 15 kHz, two slots may constitute one subframe, and in this case, the length of the slot may be 0.5 ms and the length of the subframe may be 1 ms. As another example, in the case of an NR system, the subcarrier spacing (μ) may be one of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz, and the number of slots included in one subframe depending on the subcarrier spacing (μ) may be 1, 2, 4, 8, and 16.

[0059] In the time-frequency domain, a basic unit of a resource may be a resource element (RE) (406), and the RE (406) may be expressed by an OFDM symbol index and a subcarrier index. A resource block may include a plurality of resource elements. In an NR system, a resource block (RB) (or physical resource block (PRB)) (407) may be defined by N_SCRB consecutive subcarriers in the frequency domain. The number of subcarriers may be N_SCRB = 12. The frequency domain may include common resource blocks (CRBs). A physical resource block (PRB) may be defined in a bandwidth part (BWP) in the frequency domain. The CRB and PRB numbers may be determined differently depending on the subcarrier spacing. In an LTE system, an RB may be defined by Nsymb consecutive OFDM symbols in the time domain and N_SCRB consecutive subcarriers in the frequency domain.

[0060] In NR and / or LTE systems, scheduling information for downlink data or uplink data may be transmitted from a base station (110) to a terminal (120) via downlink control information (DCI). In various embodiments, the DCI may be defined according to various formats, and each format may indicate whether the DCI includes scheduling information for uplink data (e.g., UL grant), scheduling information for downlink data (DL resource allocation), whether it is compact DCI with small control information size, whether it is fall-back DCI, whether spatial multiplexing using multiple antennas is applied, and / or whether it is DCI for power control. For example, NR DCI format 1_0 or NR DCI format 1_1 may include scheduling for downlink data. Also, for example, NR DCI format 0_0 or NR DCI format 0_1 ​​may include scheduling for uplink data.

[0061] As described above, FIG. 4 illustrates an example of a downlink and uplink slot structure in a wireless communication system. In particular, FIG. 4 illustrates the structure of a resource grid of a 3GPP NR system. Referring to FIG. 4, a slot may include a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. A signal may be composed of part or all of the resource grid. In addition, the number of OFDM symbols included in a slot may generally vary depending on the length of a cyclic prefix (CP). In FIG. 4, for convenience of explanation, a case in which a slot is composed of 14 OFDM symbols is illustrated, but the signal referred to in the present disclosure does not specify the symbol configuration. In addition, the modulation method of the generated signal is not limited to a specific value of QAM (Quadrature Amplitude Modulation), and can follow the modulation methods of various communication standards, such as BPSK (Binary phase-shift keying) and QPSK (Quadrature Phase Shift Keying).

[0062] While various embodiments of the present disclosure are described based on an LTE communication system or an NR communication system, the present disclosure is not limited thereto and can be applied to various wireless communication systems for transmitting downlink or uplink control information. Furthermore, the present disclosure can also be applied to unlicensed bands as needed, in addition to licensed bands.

[0063] Hereinafter, in the present disclosure, higher layer signaling or higher signal may be a signal transmission method in which a base station (110) transmits a downlink data channel of a physical layer to a terminal (120), or a terminal (120) transmits a signal to a base station (110) using an uplink data channel of a physical layer. According to one embodiment, the higher layer signaling may include at least one of radio resource control (RRC) signaling, signaling according to an F1 interface between a centralized unit (CU) and a distributed unit (DU), or a signal transmission method transmitted through a media access control (MAC) control element (MAC CE). In addition, according to one embodiment, the higher layer signaling or higher signal may include system information commonly transmitted to a plurality of terminals (120), for example, a system information block (SIB).

[0064] In a 5G wireless communication system, a synchronization signal block (SSB) (also referred to as an SS block, SS / PBCH block, etc.) may be transmitted for initial access, and the synchronization signal block may be composed of a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). In the initial access phase when a terminal first accesses the system, the terminal may acquire downlink time and frequency domain synchronization and a cell identity (cell ID) from a synchronization signal through a cell search procedure. The synchronization signal may include a PSS and an SSS. The terminal may receive a PBCH including a master information block (MIB) from a base station to acquire system information and basic parameter values ​​related to transmission and reception, such as system bandwidth or related control information. Based on the received PBCH, the terminal can decode the physical downlink control channel (PDCCH) and physical downlink shared channel (PDSCH) to obtain a system information block (SIB). Afterwards, the terminal can exchange identities with the base station through a random access phase and undergo registration, authentication, and other steps to initially access the network.

[0065] As described above, one slot can include 14 symbols, and in a 5G communication system, the uplink-downlink configuration of symbols and / or slots can be set in three stages.

[0066] In the first method, the uplink-downlink of a symbol and / or slot can be configured semi-statically through cell-specific configuration information via system information at the symbol level. More specifically, the cell-specific uplink-downlink configuration information via system information may include uplink-downlink pattern information and reference subcarrier information. The uplink-downlink pattern information may indicate a pattern periodicity, the number of consecutive downlink slots from the start of each pattern, the number of symbols in the next slot, the number of consecutive uplink slots from the end of the pattern, and the number of symbols in the next slot. Slots and symbols that are not indicated as uplink or downlink may be considered flexible slots / symbols.

[0067] In a second way, through user-specific configuration information via dedicated upper layer signaling, a flexible slot or a slot containing flexible symbols can be indicated by the number of consecutive downlink symbols from the start symbol of the slot and the number of consecutive uplink symbols from the end of the slot, or by the entire downlink or the entire uplink of the slot, respectively.

[0068] In a third method, in order to dynamically change the downlink signal transmission and uplink signal transmission sections, symbols indicated as flexible symbols in each slot (e.g., symbols not indicated as downlink or uplink) can be indicated as downlink symbols, uplink symbols, or flexible symbols, through a slot format indicator (SFI) included in a downlink control channel. The slot format indicator can select one index from a table (e.g., 3GPP TS 38.213 Table 11.1.1-1) in which the uplink-downlink configuration of 14 symbols in one slot is preset.

[0069] FIG. 5 illustrates examples of antenna ports used per slot in a cross division duplex (XDD) system according to various embodiments of the present disclosure.

[0070] In the conventional 5G system (e.g., NR (new radio)), the transmission and reception method through uplink or downlink can be performed based on TDD (time division duplex) and FDD (frequency division duplex). In addition, advanced duplex, which is being studied as one of the next-generation mobile communication technologies, may further include XDD (cross division duplex) or FD (full duplex). In particular, with respect to the XDD system, as an operation method of the base station, a method may be considered in which some of the transmission RUs (radio units) (e.g., TXRUs) of the base station are used for downlink, and the remaining some are used for uplink (see, for example, 3GPP RAN1 #109-e). However, this is only an example, and it is obvious that various embodiments of the present disclosure may include various operations according to settings and reports in the XDD environment described below being performed not only by the base station but also by the terminal.

[0071] More specifically, regarding the XDD system, the 5G wireless communication system has introduced additional coverage expansion technology in addition to the LTE (long-term evolution) communication service, so the actual coverage of the 5G wireless communication service can generally utilize the TDD system, which is suitable for services with a high proportion of downlink traffic. In addition, as the center frequency increases to expand the frequency band, the signal attenuation (path loss) according to the distance between the base station and the terminal increases, requiring the need for coverage improvement of the 5G wireless communication system. In particular, the proportion of downlink traffic is relatively higher than that of uplink, and in order to support services with this traffic pattern, the ratio of downlink to uplink in the time domain can be set higher. In this situation, because the transmission power of the terminal is lower than that of the base station, improving the coverage of the uplink channel can be said to be a key requirement for the 5G mobile communication service.

[0072] Physical methods for improving uplink channel coverage between base stations and terminals include increasing the terminal's transmit power, increasing uplink time resources, or changing the center frequency. However, changing the center frequency may be limited, as the available frequencies are pre-determined by each network operator and / or carrier. Furthermore, increasing the terminal's maximum transmit power may also be limited, as the maximum transmit power of the terminal is standardized to account for interference and other factors.

[0073] In consideration of the above, in the recent Release 18 system, in order to improve the coverage of base stations and terminals, a method is being considered in which uplink and downlink resources can be divided in the frequency domain, like an FDD (frequency division duplex) system, rather than dividing the ratio only in the time domain according to the traffic proportion of uplink and downlink under a TDD (time division duplex) system. In one embodiment, a system that can flexibly divide uplink resources and downlink resources in the time domain and the frequency domain may be referred to as an XDD (cross division duplex) system. An XDD system may also be referred to as a Flexible TDD system, a Hybrid TDD system, a TDD-FDD system, a Hybrid TDD-FDD system, or other similar names. For convenience of description, according to various embodiments of the present disclosure, the present disclosure is described as an XDD system. According to one embodiment, in an XDD slot, a base station and a terminal may use a portion of the resources for downlink transmission and reception and the remaining portion for uplink transmission and reception, and such division may be performed based on the frequency domain or antenna port.

[0074] According to various embodiments of the present disclosure, with reference to the above-described XDD system and FIG. 5, a slot configuration utilizing XDD may be configured with a D-slot (501) for transmitting and receiving a downlink, a U-slot (505) for transmitting and receiving an uplink, and an X-slot (502, 503, 504) for simultaneously transmitting and receiving a downlink and an uplink using XDD.

[0075] More specifically, when the base station has 16 antenna ports (for example, 16 ports), the base station and the terminal can transmit and receive downlink signals or uplink signals by using all 16 antenna ports (510, 520) on the D-slot (510) and the U-slot (505), respectively. In addition, the base station and the terminal can transmit and receive downlink signals by using 8 ports (515), which are some of the antenna ports, on the X-slot (502, 503, 504), and receive uplink signals by using the remaining 8 ports (525). Here, the X-slots (502, 503, 504) are slots defined in the XDD system and may include slots in which the base station or the terminal can operate in a full-duplex (FD) mode or an XDD mode. In various embodiments, the antenna port used for configuration or reporting below is described as the antenna port of the base station for convenience, but this is only an example, and it is obvious that substantially the same or similar content may also be applied to the antenna port of the terminal.

[0076] According to various embodiments of the present disclosure, a specific number of antenna ports (e.g., 8 ports, 16 ports) is only an example and can be equally applied to terminals or base stations having various numbers of antenna ports. In addition, the number of some antenna ports (e.g., partial ports) for uplink or downlink transmission and reception on the X-slot described below can include any number, and the sum of the numbers of antenna ports used for uplink or downlink transmission and reception may not necessarily include the number of all antenna ports of the terminal or base station.

[0077] FIG. 6 illustrates an example for reporting channel state information (CSI) in an XDD system according to various embodiments of the present disclosure. More specifically, referring to FIG. 6, a process for reporting CSI is described when a base station and a terminal use uplink or downlink transmission and reception via a partial port on an X-slot.

[0078] According to one embodiment, in 5G / NR, transmission of a CSI-RS (reference signal) and CSI reporting can be utilized as one of the methods for estimating a downlink channel. Each terminal can estimate a downlink channel through the CSI-RS received from the base station, quantize it, and report it to the base station. To this end, the base station can set information related to CSI reporting to the terminal through an RRC (radio resource control) message, which is a higher layer parameter. The information related to the CSI report set by the base station can include the CSI-ReportConfig field as shown below, and the type of CSI feedback information can be indicated through the reportQuantity setting, which is one of the information elements included in the field.

[0079]

[0080] For example, when a base station is configured to report PMI to a terminal via reportQuantity, the type of PMI (precoding matrix indicator) to be reported can be configured via the CodebookConfig field. Using the above-described information, the base station can configure the type of codebook, the N1 parameter and the N2 parameter indicating the antenna port configuration (e.g., port configuration) of the CSI-RS, etc. After receiving the CSI-RS, the terminal can estimate the downlink channel and, based on this, report an appropriate PMI to the base station.

[0081] As described above, the base station can be configured to report antenna port settings for each slot and corresponding RI (rank indicator), PMI, or CQI (channel quality indicator) to the terminal. Accordingly, the terminal can generate at least one CSI (e.g., including at least one of RI, PMI, or CQI) report corresponding to each antenna port for each slot and transmit it to the base station. At this time, when partial port CSI on the X-slot is configured, the terminal needs to transmit both the first report (Report 1: {CRI x - PMI x1 - RI y1 - CQI z1}) (605) for all antenna ports (e.g., 16 ports) on the D-slot and the second report (Report 2: {CRI y - PMI x2 - RI y2 - CQI z2}) (615) for some antenna ports (e.g., 8 ports) for downlink transmission and reception on the X-slot to the base station.

[0082] More specifically, according to the CSI reporting method supported by general 5G / NR, the base station may need to set up separate CSI reports and receive separate reports in order to obtain CSI on the D-slot and CSI on the X-slot.

[0083] For example, the CSI-RS port mapping of a base station using 16 ports for downlink transmission and reception can be expressed as the first antenna port (810) of Fig. 8. At this time, if the base station uses a Type I codebook, the base station can set nrOfAntennaPorts among the parameters set to the terminal through the CodebookConfig field to four-two-TypeI-SinglePanel.

[0084] In contrast, when some of the 16 ports (e.g., 8 ports) on the X-slot are used for downlink transmission and reception, the CSI-RS port mapping of the base station for downlink channel estimation can be expressed as the second antenna port (820) of FIG. 8. In this case, the base station can set nrOfAntennaPorts of the configuration information to two-two-TypeI-SinglePanel.

[0085] As described above, in order to estimate the downlink channel on the D-slot and the X-slot, the base station may individually require a CSI-Report setting corresponding to each slot, as shown in FIG. 7.

[0086] Meanwhile, as described above, the terminal can perform a separate CSI report corresponding to each CSI-Report configuration, and in this case, the downlink port configuration on the X-slot can use a part of the downlink port configuration of the D-slot. Therefore, the channel vector on the D-slot (e.g., reported from the terminal via PMI) and the channel vector on the X-slot can include similar results with respect to certain values. This similarity in the channel vector reporting process is specifically described in FIG. 8.

[0087] Various embodiments of the present disclosure, based on the above, propose a method for reducing payload bits for feedback by supporting PMI reporting for D-slots and PMI reporting for X-slots in an offset form. In particular, as a prerequisite for supporting such a PMI reporting method, a signaling method is proposed for calculating and reporting D-slot PMI and X-slot PMI to a terminal with reduced bits by defining or changing upper layer parameters (e.g., RRC messages).

[0088] FIG. 7 illustrates an example for transmitting a partial port CSI-RS (channel state information-reference signal) in an XDD system according to various embodiments of the present disclosure.

[0089] More specifically, with reference to FIG. 7, a base station and a terminal may utilize a new CSI report configuration method and a new CSI report performing method for operation according to various embodiments of the present disclosure.

[0090] According to various embodiments, although not illustrated in FIG. 7, the base station and the terminal may perform a process of transmitting and receiving terminal capability information prior to the procedure disclosed in FIG. 7. However, each of the steps below is merely an example and may not be considered essential components, and it is obvious that, according to one embodiment, some of the various steps included in FIG. 7 may be performed without exception.

[0091] More specifically, the terminal may transmit capability information of the terminal regarding XDD support to the base station. According to one embodiment, the capability information of the terminal may be transmitted by a request of the base station or without a separate request. Specifically, the base station may transmit and receive signals with a plurality of terminals, and only some of the plurality of terminals may be terminals that support the XDD system. If the terminals from which the base station transmits and receives signals do not support the XDD system, the base station may transmit and receive information regarding XDD, which may result in unnecessary waste. Therefore, the base station needs to receive the capability information of the terminal regarding XDD support to identify the terminal that supports XDD. The base station may receive the capability information of the terminal regarding XDD support from the terminal that supports XDD through upper layer signaling, but is not limited thereto, and may receive it through various signaling or parameters.

[0092] In step (710), the base station may transmit information for setting up CSI reporting to the terminal. The CSI reporting settings set by the base station may include setting information for a D-slot or setting information for an X-slot.

[0093] According to various embodiments of the present disclosure, a base station may transmit information for configuring an X-slot CSI report separately from a D-slot CSI report via a higher layer (e.g., an RRC message). More specifically, the CSI report configuration that the base station transmits to a terminal may additionally include a field for CSI reporting for an X-slot in addition to a field for a D-slot CSI report (i.e., using one piece of CSI report configuration information). This may mean including a partialPortCSI-ReportConfig for an X-slot within a CSI-ReportConfig.

[0094] According to one embodiment, in order to report D-slot CSI and X-slot CSI based on one CSI reporting configuration, the base station may configure a reference CSI-Report configuration to be reported to the terminal through a higher layer and the CSI of the X-slot based on the reference CSI-Report configuration. For example, as shown below, the CSI-ReportConfig field of a general RRC message may further include a new field, partialPortCsi-Report.

[0095]

[0096] According to one embodiment, when the above-described information (e.g., partialPortCsi-Report) is set to "enabled", the terminal may identify some antenna ports corresponding to a partial port (e.g., X-slot) by referring to the partialPortCsi-ReportConfigId indicated therewith, and may calculate and report channel information (e.g., CSI) based thereon.

[0097] According to one embodiment, the base station may further set the partialPortCsi-ReportConfig field corresponding to partialPortCsi-ReportConfigId in the RRC message as follows, thereby instructing the terminal on a measurement and calculation method for partialPort CSI.

[0098]

[0099] According to one embodiment, the terminal may calculate CSI for a downlink channel (e.g., a channel through a partial port) transmitted and received on an X-slot by referring to PartialPortCSI-ReportConfig corresponding to partialPortCSI-ReportConfigId when partialPortCsi-Report is set to "enabled" via an RRC message.

[0100] According to various embodiments, a method for a base station to instruct a terminal on information for calculating partial port CSI is described in detail below.

[0101] In one embodiment, the base station may configure a codebook to be used when calculating partial port CSI for the terminal. In this case, since the number of CSI-RS ports used for calculating partial port CSI (e.g., ports used for X-slot downlink channel estimation) is different from the number of reference CSI-RS ports (e.g., ports used for D-slot downlink channel estimation), additional codebook configuration may be required. Therefore, the base station may configure a codebook to be used for reporting partial port CSI through a new field, partialPortCodebookConfig, in partialPortCSI-ReportConfig as follows.

[0102]

[0103] In one embodiment, the base station may set a CSI-RS port index to be used when calculating partial port CSI for the terminal. In one embodiment, the terminal may estimate a downlink channel and calculate and report CSI after receiving a reference CSI-RS, and may use some of the estimated downlink channels to calculate partial port CSI. To this end, the terminal needs to receive information from the base station regarding which of the reference CSI-RS ports it should use to calculate the partial port CSI. For example, the base station may map 16 port CSI-RSs to estimate D-slot CSI, and use some of these 8 ports (e.g., 8 partial ports) on the X-slot. In this case, the base station needs to inform the terminal of the port index to be used for the X-slot, and for this purpose, a new field, PartialPortCSI-ReportConfig, may further include a partialPortIndication field. As described above, the base station can inform the terminal of the port index to be used when calculating partial port CSI through the partialPortIndication field, and specific examples thereof can include various methods as follows.

[0104] In one embodiment, the base station may explicitly indicate the port index to the terminal. For example, the partialPortIndication field set by the base station to the terminal may include the index values ​​of the ports corresponding to the partial ports.

[0105]

[0106] In one embodiment, the base station may indicate to the terminal a bitmap corresponding to a port index. For example, the partialPortIndication field that the base station sets to the terminal may include a bitmap in which bits corresponding to some port indexes that the terminal needs to set on the X-slot among the port indexes included by the base station are indicated as 1, and the remaining bits are indicated as 0.

[0107]

[0108] According to one embodiment, the base station may indicate to the terminal a shape corresponding to a port index. For example, the partialPortIndication field that the base station sets to the terminal may include a value of a shape corresponding to some port indexes that the terminal needs to set on the X-slot among the port indexes included by the base station. According to one embodiment, the shape here may include lowerHalf, upperHalf, leftHalf, or rightHalf based on the physical location of the antenna port, and separate configuration information for defining this (e.g., provided as a look-up table or a predefined table, etc.) may be transmitted to the terminal.

[0109]

[0110] According to various embodiments of the present disclosure, a base station may transmit information for configuring an X-slot CSI report together with a D-slot CSI report via a higher layer (e.g., an RRC message). More specifically, the CSI report configuration transmitted by the base station to a terminal may include a field for a D-slot CSI report and a field for a CSI report for an X-slot that references it (i.e., using two pieces of CSI report configuration information). This may mean including a new field for a D-slot configuration Id referenced in the CSI-ReportConfig for the X-slot.

[0111] According to one embodiment, the base station may separately indicate to the terminal a reference CSI report configuration to serve as a reference in order to reduce payload bits when reporting CSI (e.g., PMI value) of an X-slot. For example, as shown below, CSI-ReportConfig may include a new field, partialPortCsi-Report, and instead of setting separate ConfigId information for this, a referenceCSI-ReportConfig ID may be further indicated for reference.

[0112]

[0113] For example, if the value of partialPortCsi-Report is set to 1, the terminal can calculate PMI based on the method set in CSI-ReportConfig Id 1 (e.g., ConfigID set for D-slot CSI acquisition), and based on this, calculate PMI using the method set in CSI-Report (separate Config ID set for X-slot CSI acquisition), and report the offset between them.

[0114] In step (720), the base station can transmit CSI-RS to the terminal.

[0115] In step (730), the terminal may calculate CSI based on the received CSI-RS. More specifically, the terminal may calculate CSI based on each piece of configuration information received in step (710), wherein the CSI may include a PMI value.

[0116] In step (740), the terminal may report CSI calculated according to the reporting settings to the base station. To calculate the partial port CSI to be reported to the base station, the terminal may further set reporting rules in advance (e.g., in step (710)), and specific operations according to these rules are described below with reference to FIGS. 8 and 9.

[0117] FIG. 8 illustrates an example of an antenna port for partial port CSI reporting in an XDD system according to various embodiments of the present disclosure.

[0118] As described above in FIGS. 5 and 6, the downlink port configuration on the X-slot may use a part of the downlink port configuration on the D-slot, so that the channel vector on the D-slot and the channel vector on the X-slot may include similar results with respect to a certain value.

[0119] For example, referring to FIG. 8, based on a first antenna port (810) that uses 16 ports for downlink transmission and reception, the strongest beam on a 2D-DFT (2 dimensional-discrete Fourier transform) beam grid can be identified as (n1:n2=10:7) (815). Furthermore, based on a second antenna port (820) that uses some of the 16 ports (e.g., 8 ports) on an X-slot for downlink transmission and reception, the strongest beam on a 2D-DFT beam grid can be identified as (n1:n2=6:7) (825). In this way, due to the similarity of the channel vectors, the n2 index on the D-slot can include almost the same result as the n2 index on the X-slot. That is, since at least one index can be similar according to two CSI feedback results corresponding to each slot, various embodiments of the present disclosure can reduce the number of bits for CSI feedback by utilizing such results.

[0120] For example, Tables 1 and 2 below show the PMI similarity between two port settings obtained through system level simulation.

[0121] Referring to Table 1, the D-slot CSI-RS port configuration may be based on the antenna ports of (N1, N2)=(8, 2), and the X-slot CSI-RS port configuration may be based on the antenna ports of (N1, N2)=(4, 2).

[0122] i_12 (n2) index offsetValue-101Ratio2.44%92.3%5.26%

[0123] Referring to Table 2, the D-slot CSI-RS port configuration may be based on the antenna ports of (N1,N2)=(4,2), and the X-slot CSI-RS port configuration may be based on the antenna ports of (N1,N2)=(2,2).

[0124] i_12 (n2) index offsetValue-101Ratio3.4%93.9%2.7%

[0125] What the above results mean is that when comparing the D-slot CSI report and the X-slot CSI report, in 92.3% or 93.9% of cases, one of the indices of the PMI reported, i_12 (e.g., n2 index), is substantially the same. Furthermore, it can be seen that the difference in the indices is between -1 and 1 even in cases including almost all probabilities. Accordingly, when the base station receives a report of the i_12 index of the D-slot, in most cases, the i_12 index of the X-slot does not need to be separately reported, or it may be sufficient to simply receive a report of the difference in index values. In consideration of the above, according to various embodiments of the present disclosure, FIGS. 8 and 9 describe specific methods for reporting when reporting a Partial port CSI corresponding to step (740) of FIG. 7.

[0126] According to various embodiments of the present disclosure, when a terminal calculates a partial port CSI and reports a CSI value (e.g., described as a PMI value for convenience below), the number of payload bits required for reporting the CSI value can be reduced by utilizing the similarity with the reference CSI value as described above. As a prerequisite for this, additional parameter settings for the method of reporting the partial port PMI may be required. It goes without saying that additional information set by the base station to receive the report in this way can be transmitted to the terminal in step (710) or separately.

[0127] According to various embodiments, the base station may instruct the terminal on the reporting rule by setting the relevant parameters in the new field PartialPortCSI-ReportConfig.

[0128] Specifically, the base station can instruct the terminal to explicitly report the difference between the reference PMI index (e.g., the CSI measurement result on the D-slot) and the partial port PMI index (e.g., the CSI measurement result on the X-slot). For example, the base station can set partialPortPmiOffset as follows to report the above-mentioned difference within an offset range value represented by an integer.

[0129]

[0130] According to one embodiment, when the upper layer information is set as described above, the terminal may report the offset of the partial port PMI index within the range of the set values. For example, the terminal may report a specific value (-2, -1, 0, 1, or 2) within the offset range of 2 for i_11 among the PMI indices, or a specific value (-1, 0, or 1) within the offset range of 1 for i_12. For example, when the index of the reference PMI is identified as (i_11, i_12) = (8, 3) and the index of the partial port PMI is identified as (i_11, i_12) = (8, 2), the terminal may report a value (0, -1) corresponding to the offset value to the base station instead of reporting (8, 2) to the base station for the partial port PMI. That is, the terminal may reduce the number of bits for reporting the PMI to the base station by using the offset value rather than using a large number of bits for the PMI index value.

[0131] According to one embodiment, the terminal may further receive information about a D-slot associated with a reference PMI index for calculating a difference (e.g., an offset value) with a partial port PMI index (or configuration information associated with the D-slot). For example, the base station may separately indicate to the terminal the slot-wise difference between the D-slot associated with the reference PMI index and the X-slot (e.g., slotoffset{0, 1, 2, or ...}). Alternatively, the D-slot associated with the reference PMI index may be indicated by a reference CSI reporting configuration of a CSI-ReportConfig received by the terminal, or may be indicated by a reportConfigId associated with a referenceCSI-ReportConfigId referenced by a partialportCSI-Report received by the terminal.

[0132] As another specific example, the base station can indicate to the terminal an offset value, which is the difference between the reference PMI index and the partial port PMI index, through an index in the table, based on a predefined (or set) table.

[0133]

[0134] At this time, the pmiOffset table (e.g., a predefined lookup table) can be set in advance as in the example below.

[0135]

[0136] For example, if the index of the reference PMI is identified as (i_11, i_12)=(8, 3) and the index of the partial port PMI is identified as (i_11, i_12)=(8, 2), the terminal can report the index (2, 1) to the base station based on the preset pmiOffsettable 1 instead of reporting (8, 2) to the base station for the partial port PMI. That is, the terminal can reduce the number of bits for reporting the PMI by using the index value according to the table rather than using a large number of bits for the PMI index value to the base station.

[0137] FIG. 9 illustrates an example of information for reporting partial port CSI according to various embodiments of the present disclosure. More specifically, the information related to the CSI reporting described in FIG. 9 may correspond to the signaling between the base station and the terminal in step (740) of FIG. 7.

[0138] According to various embodiments of the present disclosure, when the CSI reporting configuration transmitted by the base station to the terminal includes a field for CSI reporting for an X-slot in addition to a field for D-slot CSI reporting, the terminal may perform the following uplink transmission (e.g., the first CSI reporting information (910) below).

[0139] According to one embodiment, referring to the first CSI report information (910), when the terminal performs a separate partial port CSI report based on one configuration information, the terminal may transmit the CSI report to the base station through UCI (uplink control information) by adding a new mapping rule to the general CSI report mapping rule (e.g., refer to 3GPP TS 38.212-Table 6.3.1.1.2-1~10). For example, UCI having a bit sequence of a_0 to a_A-1 may be further mapped and transmitted to PartialPort CSI report #1 for partial CSI report as well as CSI report #1 to CSI report #n for CSI report on the existing D-slot. In this case, PartialPort CSI report #1 may include a PMI offset value according to the above-described reporting rule as a CSI field.

[0140] According to various embodiments of the present disclosure, when a CSI reporting configuration transmitted by a base station to a terminal includes a field for D-slot CSI reporting and a field for CSI reporting for an X-slot referencing the same, the terminal may perform the following uplink transmission (e.g., the second CSI reporting information (920) below).

[0141] According to one embodiment, referring to the second CSI report information (920), when the terminal performs partial port CSI reporting based on two pieces of configuration information, each CSI report configuration may be mapped to a different CSI report number. For example, a UCI having a bit sequence of a_0 to a_A-1 may be mapped and transmitted to CSI report #1 for partial CSI reporting to CSI report #n for partial CSI reporting. Accordingly, the terminal may report by replacing the PMI offset in the position corresponding to the PMI within the CSI fields used for general CSI reporting.

[0142] FIGS. 10A and 10B illustrate the number of bits required to report partial port CSI according to various embodiments of the present disclosure.

[0143] As described in FIGS. 5 to 9, the downlink port configuration on the X-slot can use a part of the downlink port configuration of the D-slot, so that by utilizing the similarity between the channel vector on the D-slot and the channel vector on the X-slot, the base station and the terminal can transmit and receive CSI (e.g., PMI) feedback using a reduced number of bits.

[0144] Referring to FIG. 10a, in Type 1 codebook mode 1, for 1 layer CSI reporting, an example (1010) of bit reduction of X-slot PMI based on D-slot feedback information is illustrated.

[0145] In one embodiment, the base station may refer to a PMI value for a channel on a D-slot based on the similarity of channel vectors, and may instruct the terminal not to report a PMI value for a channel on an X-slot, or to report it with a 1-bit or 2-bit offset based on the PMI value for the channel on the D-slot. This instruction of the base station may be set through upper layer signaling for CSI reporting, or may be set separately. Referring to FIG. 10A, compared to a value reported by the terminal for channel estimation on an X-slot using a general PMI index value, the number of bits required for PMI reporting may be significantly reduced by not reporting an index for channel estimation on an X-slot based on the similarity of channels, or by reporting an offset value of 1-bit or 2-bits.

[0146] For example, if there are 8 antenna ports for CSI-RS on the D-slot, the antenna ports (N1, N2) on the D-slot may be (2,2), and the antenna port on the X-slot may be (2,1). In this case, the terminal may require a bit width of 3 bits to report the PMI index for the channel on the general X-slot. However, according to the embodiments of the present disclosure, if the base station instructs not report in order to use the same value as the PMI value for the channel on the D-slot for the reporting value for the channel on the X-slot, the PMI index reported by the terminal may be reduced to 0 bits. In addition, if the base station instructs to report with an offset of 1 bit or 2 bits, the PMI index reported by the terminal may be reduced to 1 bit or 2 bits. This can be equally applied to mapping shapes of various antenna ports when there are 16 or 32 antenna ports, and can bring about the same bit-saving effect.

[0147] Referring to FIG. 10b, in a Type 2 codebook, when the number of basis beams is 2 (L=2), an example (1020) of bit reduction of X-slot PMI based on D-slot feedback information is illustrated. Even in this case, as in FIG. 10a, the number of bits required for PMI reporting can be significantly reduced by not reporting an index for channel estimation on the X-slot or reporting an offset value of 1 or 2 bits based on channel similarity, compared to the value reported by the terminal for channel estimation on the X-slot using a general PMI index value. In particular, due to the characteristics of the Type 2 codebook using two basis beams, the bit reduction effect can be greater as the number of antenna ports increases, compared to the Type 1 codebook.

[0148] The 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.

[0149] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure.

[0150] These 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-ROMs (CD-ROMs), digital versatile discs (DVDs) or other forms of optical storage devices, magnetic cassettes, or may be stored in memories formed by a combination of some or all of these. In addition, each configuration memory may include multiple copies.

[0151] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present disclosure.

[0152] In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0153] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. In a wireless communication system, a user equipment (UE) transceiver; and Including a controller coupled to the above transmitter and receiver, The above controller, Receive first information from a base station, the first information setting a first CSI (channel state information) report related to some of the antenna ports of the base station, From the above base station, receive a CSI-RS (reference signal), and configured to transmit the first CSI report to the base station based on the first information, The terminal wherein the first CSI report includes values obtained based on the second CSI report related to all of the antenna ports of the base station.

2. In claim 1, The above first CSI report is a report for a first slot including an XDD (cross division duplex) slot, and The above second CSI report is a terminal report for a second slot including a DL (downlink) slot.

3. In claim 1, the first information is: At least one of information of a codebook for the first CSI report or information indicating an index of some of the antenna ports of the terminal, or A terminal including information indicating an ID (identifier) of second information that sets the second CSI report.

4. In claim 1, The first PMI (precoding matrix indicator) information included in the first CSI report includes an offset value based on the second PMI information included in the second CSI report, and A terminal wherein the first information includes information that sets the offset value to report some or all of the indices of the first PMI, or not to report them.

5. In claim 4, The above offset value is a terminal indicated by an index value based on a predefined table.

6. In a wireless communication system, a base station, transceiver; and Including a controller coupled to the above transmitter and receiver, The above controller, Transmit first information to a user equipment (UE) for setting a first CSI (channel state information) report related to some of the antenna ports of the base station, The above terminal transmits CSI-RS (reference signal), and configured to receive the first CSI report from the terminal based on the first information, A base station wherein the first CSI report includes values obtained based on second CSI reports related to all of the antenna ports of the base station.

7. In claim 6, The above first CSI report is a report for a first slot including an XDD (cross division duplex) slot, and The above second CSI report is a base station report for a second slot including a DL (downlink) slot.

8. In claim 6, the first information is: At least one of information of a codebook for the first CSI report or information indicating an index of some of the antenna ports of the terminal, or A base station including information indicating an ID (identifier) of second information that sets the second CSI report.

9. In claim 6, The first PMI (precoding matrix indicator) information included in the first CSI report includes an offset value based on the second PMI information included in the second CSI report, and A base station, wherein the first information includes information that sets the offset value to report some or all of the indices of the first PMI, or not to report them.

10. In claim 9, The above offset value is a base station indicated by an index value based on a predefined table.

11. In a wireless communication system, a method performed by a user equipment (UE) is as follows: A step of receiving, from a base station, first information setting a first CSI (channel state information) report related to some of the antenna ports of the base station; A step of receiving a CSI-RS (reference signal) from the base station; and A step of transmitting the first CSI report to the base station based on the first information, A method wherein the first CSI report includes values obtained based on second CSI reports related to all of the antenna ports of the base station.

12. In claim 11, The above first CSI report is a report for a first slot including an XDD (cross division duplex) slot, and The above second CSI report is a method for reporting for a second slot including a DL (downlink) slot.

13. In claim 11, the first information is: At least one of information of a codebook for the first CSI report or information indicating an index of some of the antenna ports of the terminal, or A method comprising information indicating an ID (identifier) of second information for setting the second CSI report.

14. In claim 11, The first PMI (precoding matrix indicator) information included in the first CSI report includes an offset value based on the second PMI information included in the second CSI report, and A method wherein the first information includes information that sets the offset value to report some or all of the indices of the first PMI, or not to report them.

15. In claim 14, The above offset value is indicated as an index value based on a predefined table.

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