Method and apparatus for saving energy in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Specifically, a method performed by a terminal in a wireless communication system comprises the steps of: receiving, from a base station, an RRC message including information indicating the number of ports; receiving, from the base station, a message for deactivating at least one port among the ports whose number corresponds to the number of ports, wherein the message includes resource allocation information in a frequency domain associated with the at least one port; receiving, from the base station, a CSI-RS via a port that does not include at least one antenna port deactivated based on the message, among ports corresponding in number to the number of ports; and reporting the CSI acquired on the basis of the CSI-RS to the base station.

Description

Technical Field

[0001] The present disclosure relates to wireless communication systems, and more particularly, to methods and apparatus for energy saving in wireless communication systems. Background Art

[0002] 5G mobile communication technology defines a wide frequency band, making high transmission rates and new services possible, and can be implemented not only in "below 6 GHz" frequency bands such as 3.5 GHz, but also in "above 6 GHz" frequency bands called millimeter waves including 28 GHz and 39 GHz. In addition, in order to achieve a transmission rate 50 times faster than 5G mobile communication technology and an ultra-low latency of one-tenth of 5G mobile communication technology, the implementation of 6G mobile communication technology (called a super 5G system) in a terahertz (THz) frequency band (e.g., 95 GHz to 3 THz frequency band) has been considered.

[0003] In the early stages of 5G mobile communications technology development, in order to support services and meet performance requirements associated with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC) and massive Machine-Type Communications (mMTC), standardization is already underway on the following: beamforming and massive multiple-input multiple-output (MIMO) for alleviating radio wave path loss and increasing radio wave transmission distance in millimeter waves; support for basic parameter sets (e.g., operating multiple subcarrier spacings) for efficient utilization of millimeter wave resources and dynamic operation of time slot formats; initial access technology for supporting multi-beam transmission and broadband; definition and operation of BandWidth Part (BWP); new channel coding methods, such as Low Density Parity Check (LDPC) codes for large amounts of data transmission and polarization codes for highly reliable transmission of control information; L2 preprocessing; and network slicing for providing dedicated networks dedicated to specific services.

[0004] Currently, in view of the services that 5G mobile communication technology will support, discussions are ongoing on improvements and performance enhancements of initial 5G mobile communication technology, and there is already physical layer standardization on technologies such as: Vehicle-to-everything (V2X), for assisting driving determination of autonomous vehicles based on information about the location and status of the vehicle sent by the vehicle, and for enhancing user convenience; New Radio Unlicensed (NR-U), for system operation in compliance with various regulatory requirements in unlicensed bands; NR UE power saving; Non-Terrestrial Network (NTN), which is UE-satellite direct communication for providing coverage in areas where communication with terrestrial networks is unavailable; and positioning.

[0005] In addition, in terms of air interface architecture / protocol, standardization is already underway on technologies such as: Industrial Internet of Things (IIoT), which is used to support new services through interworking and integration with other industries; Integrated Access and Backhaul (IAB), which is used to provide nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner; Mobility enhancement, including conditional handover and dual active protocol stack (DAPS) handover; and two-step random access, which is used to simplify the random access procedure (2-step RACH (Random Access Channel) for NR). In terms of system architecture / services, standardization is also underway on the following: 5G baseline architecture (e.g., service-based architecture or service-based interface), which is used to combine network function virtualization (NFV) and software-defined networking (SDN) technologies; and Mobile Edge Computing (MEC), which is used to receive services based on UE location.

[0006] With the commercialization of 5G mobile communication systems, the already exponentially increasing number of connected devices will be connected to the communication network, and accordingly, it is expected that enhanced functions and performance of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research related to the following items is planned: extended reality (eXtended Reality, XR) for effectively supporting augmented reality (Augmented Reality, AR), virtual reality (Virtual Reality, VR), mixed reality (Mixed Reality, MR), etc.; improving 5G performance and reducing complexity by utilizing artificial intelligence (Artificial Intelligence, AI) and machine learning (Machine Learning, ML); AI service support; metaverse service support; and drone communication.

[0007] In addition, such developments in 5G mobile communication systems will serve not only as a basis for developing new waveforms for providing coverage of the terahertz band for 6G mobile communication technology, multi-antenna transmission technologies (such as full Dimensional MIMO (FD-MIMO), array antennas, and massive antennas), metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional spatial multiplexing technologies using orbital angular momentum (OAM), and reconfigurable intelligent surfaces (RIS), but also as a basis for developing full-duplex technologies for improving the frequency efficiency of 6G mobile communication technology and improving system networks, AI-based communication technologies for implementing system optimization by utilizing satellites and artificial intelligence (AI) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technologies for implementing services with a complexity level that exceeds the limits of UE operating capabilities by utilizing ultra-high performance communication and computing resources. Summary of the invention

[0008] Technical issues

[0009] The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for network energy saving in a wireless communication system.

[0010] Specifically, in the case where a base station adjusts transmission parameters at short time intervals for power saving and cell throughput and coverage management, relevant parameter configuration and signaling methods are provided.

[0011] Technical Solution

[0012] A method performed by a terminal in a wireless communication system according to an embodiment of the present disclosure may include: receiving a radio resource control (RRC) message including information indicating the number of ports from a base station; receiving a message for deactivating at least one port among ports corresponding in number to the number of ports from the base station, wherein the message includes resource allocation information in the frequency domain associated with the at least one port; receiving a channel state information reference signal (CSI-RS) from the base station via ports among ports corresponding in number to the number of ports but excluding at least one antenna port deactivated based on the message; and reporting channel state information (CSI) obtained based on the CSI-RS to the base station.

[0013] A method performed by a base station in a wireless communication system according to another embodiment of the present disclosure may include: sending an RRC message including information indicating the number of ports to a terminal; determining to deactivate at least one port among the ports corresponding in number to the number of ports; sending a message for deactivating at least one port to the terminal, wherein the message includes resource allocation information in the frequency domain associated with the at least one port; sending CSI-RS to the terminal via ports among the ports corresponding in number to the number of ports but excluding at least one antenna port deactivated based on the message; and receiving CSI based on the CSI-RS from the terminal.

[0014] A terminal in a wireless communication system according to another embodiment of the present disclosure may include a transceiver and a controller functionally connected to the transceiver. The controller may be configured to: receive an RRC message including information indicating the number of ports from a base station; receive a message from the base station for deactivating at least one port among ports corresponding in number to the number of ports, wherein the message includes resource allocation information in the frequency domain associated with at least one port; receive CSI-RS from the base station via ports among ports corresponding in number to the number of ports but excluding at least one antenna port deactivated based on the message; and report CSI acquired based on the CSI-RS to the base station.

[0015] A base station in a wireless communication system according to another embodiment of the present disclosure may include a transceiver and a controller functionally connected to the transceiver. The controller may be configured to: send an RRC message including information indicating the number of ports to a terminal; determine to deactivate at least one port among the ports corresponding in number to the number of ports; send a message for deactivating at least one port to the terminal, wherein the message includes resource allocation information in the frequency domain associated with the at least one port; send CSI-RS to the terminal via ports among the ports corresponding in number to the number of ports but excluding at least one antenna port deactivated based on the message; and receive CSI based on the CSI-RS from the terminal.

[0016] Technical problems to be achieved in various embodiments of the present disclosure are not limited to the above-mentioned technical problems, and other technical problems not mentioned will be clearly understood from the following description by those skilled in the art to which the present disclosure belongs.

[0017] Beneficial Effects

[0018] According to an embodiment of the present disclosure, a base station may adjust transmission parameters to reduce energy consumption by using channel state information (CSI) related parameter configuration and signaling methods.

[0019] Furthermore, according to an embodiment of the present disclosure, the CSI of a suitable UE may be measured based on configured parameters and reported to the base station.

[0020] Effects obtainable from the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood from the following description by those skilled in the art to which the present disclosure pertains. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 2 is a diagram showing the basic structure of the time-frequency resource domain of a 5G system according to an embodiment of the present disclosure.

[0022] Figure 2 is a diagram illustrating a time domain mapping structure and a beam scanning operation of a synchronization signal according to an embodiment of the present disclosure.

[0023] Figure 3 A random access procedure according to an embodiment of the present disclosure is shown.

[0024] Figure 4 A procedure for a UE to report UE capability information to a base station according to an embodiment of the present disclosure is shown.

[0025] Figure 5 The relationship between frequency band, coverage and bandwidth according to an embodiment of the present disclosure is shown.

[0026] Figure 6is a diagram showing an example of a base station deployment scenario according to an embodiment of the present disclosure.

[0027] Figure 7 is a diagram showing another example of a base station deployment scenario according to an embodiment of the present disclosure.

[0028] Fig. 8A and Figure 8B is a diagram for explaining a method for configuring CSI resources according to an embodiment of the present disclosure.

[0029] Fig. 9 is a diagram for explaining relevant parameters included in CSI resource configuration according to an embodiment of the present disclosure.

[0030] Fig.10 An example of activating / deactivating CSI resources through MAC CE (Medium Access Control-Control Element) and DCI (Downlink Control Information) according to an embodiment of the present disclosure is shown.

[0031] Fig.11A and Fig. 11B An example of a method for configuring CSI resources according to an embodiment of the present disclosure is shown.

[0032] Fig.12 Another example of a method for configuring CSI resources according to an embodiment of the present disclosure is shown.

[0033] Fig.13 Another example of a method for configuring CSI resources according to an embodiment of the present disclosure is shown.

[0034] Fig.14 The signaling procedures of the UE and the base station according to an embodiment of the present disclosure are shown.

[0035] Fig.15 is a diagram illustrating a UE transceiver in a wireless communication system according to an embodiment of the present disclosure.

[0036] Fig.16 is a block diagram showing an internal structure of a UE according to an embodiment of the present disclosure.

[0037] Fig.17 is a block diagram showing an internal structure of a base station according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0038] Hereinafter, embodiments of the present disclosure are described in detail with reference to the accompanying drawings.

[0039] When describing the embodiments, descriptions related to the technical contents known in the art to which the present disclosure belongs and which are not directly related to the present disclosure will be omitted. Such omission of unnecessary descriptions is intended to prevent the main idea of ​​the present disclosure from being obscured and to convey the main idea more clearly.

[0040] For the same reason, some components in the drawings are exaggerated, omitted or schematically shown, and the size of each component does not fully reflect the actual size. In each figure, the same reference numeral is given to the same or corresponding element.

[0041] By referring to the embodiments described in detail below in conjunction with the accompanying drawings, the advantages and features of the present disclosure and the ways to achieve them will be apparent. However, the present disclosure is not limited to the embodiments set forth below, but can be implemented in various different forms. The following embodiments are provided only to fully disclose and inform those skilled in the art of the scope of the present disclosure, and the present disclosure is defined only by the scope of the claims. Throughout the specification, the same or similar reference numerals represent the same or similar elements.

[0042] Here, it will be understood that each block of the flowchart illustration and the combination of blocks in the flowchart illustration can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device create a means for implementing the functions specified in the (multiple) flowchart blocks. These computer program instructions can also be stored in a computer-usable or computer-readable memory that can instruct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-usable or computer-readable memory produce an article of manufacture including the instruction means for implementing the functions specified in the (multiple) flowchart blocks. The computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable data processing device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable data processing device provide steps for implementing the functions specified in the (multiple) flowchart blocks.

[0043] In addition, each block can represent a module, code segment or code portion including one or more executable instructions for implementing (multiple) specified logical functions. It should also be noted that in some alternative implementations, the functions mentioned in the block may not appear in order. For example, two blocks shown in succession can actually be executed substantially concurrently, or these blocks can sometimes be executed in reverse order, depending on the functions involved.

[0044] As used in the embodiments of the present disclosure, "unit" refers to a software or hardware component that performs a predetermined function, such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC). However, "unit" does not always have a meaning limited to software or hardware. "Unit" can be constructed to be stored in an addressable storage medium or to execute one or more processors. Therefore, "unit" includes, for example, components (such as software components, object-oriented software components, class components and task components), processes, functions, attributes, programs, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays and parameters. The components and functions provided by "unit" can be combined into smaller numbers of components and "units", or divided into additional components and "units". In addition, components and "units" can be implemented as one or more CPUs in a secure multimedia card or device. In addition, in an embodiment, "unit" can include one or more processors.

[0045] The following detailed description of the embodiments of the present disclosure is directed to a new RAN (Radio Access Network) (NR) as a radio access network and a packet core (5G system, 5G core network or new generation core (NG core)) as a core network, wherein the NR and the packet core are specified in the 5G mobile communication standard disclosed by the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) as a mobile communication standardization group, but based on the determination of those skilled in the art, the main ideas of the present disclosure can be applied to other communication systems with similar technical backgrounds through some modifications without significantly deviating from the scope of the present disclosure.

[0046] In the 5G system, in order to support network automation, a network data collection and analysis function (NWDAF) can be defined. NWDAF is a network function that provides the function of analyzing and providing data collected from the 5G network. NWDAF can collect / store / analyze information from the 5G network to provide results to an unspecified network function (NF), and the analysis results can be used independently in each NF.

[0047] In the following description, for the convenience of description, the present disclosure will be described using terms and names defined in 3GPP standards (5G, NR, LTE or other similar system standards). However, the present disclosure is not limited to these terms and names, and can be applied to systems conforming to other standards in the same manner.

[0048] In addition, in the following description, for the sake of convenience, terms for identifying access nodes, terms about network entities, terms about messages, terms about interfaces between network entities, terms about various identification information, etc. are illustratively used. Therefore, the present disclosure is not limited to the terms used below, and other terms about subjects having equivalent technical meanings may be used.

[0049] In order to meet the increased demand for wireless data services after the commercialization of 4G communication systems, efforts have been made to develop improved 5G communication systems (new radio (NR)). 5G communication systems have been designed to also support millimeter wave bands (e.g., 28GHz bands) in order to achieve high data transmission rates. In 5G communication systems, technologies such as beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large antennas are discussed to reduce propagation path losses in millimeter wave bands and increase propagation transmission distances. In addition, unlike LTE, 5G communication systems support various subcarrier spacings including 15kHz, such as 30kHz, 60kHz, and 120kHz, and physical control channels use polarity coding, and physical data channels use low-density parity check (LDPC). In addition, as a waveform for uplink transmission, not only CP (Cyclic Prefix)-OFDM is used, but also DFT-S (Discrete Fourier Transform-Spread)-OFDM is used. Although LTE supports HARQ (Hybrid Automatic Repeat Request) retransmission in units of transport blocks (TB), 5G can additionally support HARQ retransmission based on code block groups (CBG), in which several code blocks (CB) are bundled in a CBG.

[0050] In addition, in order to improve the network of the system, in the 5G communication system, technologies such as evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (Device To Device, D2D), wireless backhaul, vehicle communication networks (vehicle-to-everything (V2X) networks), collaborative communications, coordinated multi-points (CoMP) and reception interference cancellation have been developed.

[0051] At the same time, the Internet has evolved from a human-centered connection network through which humans generate and consume information to an Internet of Things (IoT) network that sends / receives information between distributed components (such as things) and processes information. Internet of Everything (IoE) technology that combines big data processing technology and IoT technology through connection with cloud servers and the like has also emerged. In order to implement IoT, technical elements such as sensing technology, wired and wireless communication, and network infrastructure, service interface technology, and security technology are required. Recently, technologies such as sensor networks, machine to machine (Machine to Machine, M2M), and machine type communication (MTC) for connecting between things have been studied. In the IoT environment, smart Internet technology (Internet technology, IT) services that create new value in human life by collecting and analyzing data generated in networked things can be provided. By integrating and combining existing information technology (IT) with various industries, IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced healthcare services.

[0052] In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine (M2M) communications, and machine-type communications (MTC) can be implemented by technologies such as beamforming, MIMO, and array antennas. Cloud radio access networks (RANs) as applications of the above-mentioned big data processing technologies can also be considered as examples of the fusion between 5G technology and IoT technology. In this way, in a communication system, a variety of services can be provided to users, and in order to provide a variety of services to users, a method for providing each service in the same time period according to characteristics and a device using the method are required. Various services provided in 5G communication systems are being studied, and one of them is a service that meets the requirements of low latency and high reliability. In addition, the demand for mobile services is expanding dramatically, and location-based services (LBS), which are mainly driven by two main requirements (i.e., emergency services and commercial applications), are growing rapidly. In particular, when using a side link for communication, the NR side link system supports unicast communication, groupcast (or multicast) communication, and broadcast communication between UEs. Furthermore, unlike the LTE sidelink, which is designed to send and receive basic safety information required to operate a vehicle on the road, the NR sidelink is designed to provide more advanced services such as platooning, advanced driving, extended sensors and remote driving.

[0053] In particular, the importance of increasing the energy saving effect by enabling the base station to quickly change the transmission power of the downlink common signal is being highlighted. In general, the transmission power of the downlink common signal (e.g., PSS (Primary Synchronization Signal), SSS (Secondary Synchronization Signal), PBCH (Physical Broadcast Channel), CSI-RS, etc.) sent by the base station is determined once and maintained as is in the base station installation phase in consideration of cell coverage, etc., unless there are special circumstances. However, in the case where base station power saving is required, the base station may consider a method for increasing the energy saving effect by quickly changing the transmission power of the downlink common signal. As an example of a commercial 5G base station, the base station can be equipped with 64 transmit antennas and corresponding 64 power amplifiers in the 3.5GHz band, and can operate in a bandwidth of 100MHz. As a result, the power consumption of the base station increases in proportion to the output of the power amplifier and the operating time of the power amplifier. Compared with the LTE base station, the 5G base station has a relatively high operating frequency band, so it has the characteristics of a wide bandwidth and a large number of transmit antennas. According to these characteristics, there is an effect of increasing the data rate, but at the expense of increasing the power consumption of the base station. Therefore, the more base stations there are in the mobile communication network, the more the power consumption of the entire mobile communication network increases proportionally. Accordingly, the base station can adjust the transmission parameters to reduce power consumption. However, although the power consumption of the base station can be reduced by adjusting the transmission parameters for power saving, the cell throughput and coverage may be reduced. As a method to overcome this, the transmission parameters can be adjusted at short intervals (such as the transmission time interval (TTI)) and at the symbol level to minimize the reduction in cell throughput and coverage.

[0054] In the present disclosure, as described above, in order to reduce the energy consumption of a base station, a parameter configuration and signaling method performed by a base station is proposed to adjust channel state information (CSI) related parameters at short time intervals. Specifically, the corresponding parameters may include CSI-RS related resource configuration information, a period, the number of CSI-RS ports, the frequency domain for sending CSI-RS, etc. When the CSI-related parameter configuration and signaling method proposed in the present disclosure is applied so that the base station adjusts the transmission parameters to reduce energy consumption, it may be possible to measure the CSI of a suitable UE and report the measured CSI to the base station.

[0055] Embodiments of the present disclosure are proposed to support the above scenarios, and in particular, they aim to provide a method for adjusting transmission parameters at short time intervals for power saving of a base station and cell throughput and coverage management.

[0056] Figure 1 is a diagram showing the basic structure of the time-frequency resource domain of a 5G system according to an embodiment of the present disclosure. That is, Figure 1 is a diagram showing the basic structure of a time-frequency resource domain, where the time-frequency resource domain is a radio resource domain for sending data or control channels of a 5G system.

[0057] refer to Figure 1 , the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The smallest transmission unit in the time domain in the 5G system is the orthogonal frequency division multiplexing (OFDM) symbol, which can be OFDM symbols 102 are grouped together to form a time slot 106, and can be The number of time slots is grouped together to form a subframe 105. One subframe 105 may have a length of 1.0 ms, and 10 subframes may be grouped together to form a 10 ms frame 114. The minimum transmission unit in the frequency domain is a subcarrier, and the total system transmission bandwidth may consist of a total of N BW It is composed of 104 subcarriers.

[0058] The basic resource unit in the time-frequency domain is a resource element (RE) 112, which can be represented by an OFDM symbol index and a subcarrier index. A resource block (RB) or a physical resource block (PRB) can be defined as a 110 consecutive subcarriers. In the 5G system, And the data rate can be increased in proportion to the number of RBs scheduled to the UE.

[0059] In the 5G system, the base station can map data in units of RBs, and generally perform scheduling for a certain UE in units of RBs constituting a time slot. In other words, in the 5G system, the basic time unit for scheduling can be a time slot, and the basic frequency unit for scheduling can be an RB.

[0060] Number of OFDM symbols is determined based on the length of a cyclic prefix (CP) added to each symbol to prevent inter-symbol interference, and, for example, when a normal CP is applied, When the application extends CP, The extended CP can be applied to a system with a relatively long radio wave transmission distance compared to the radio wave transmission distance of the normal CP, thereby maintaining the orthogonality between symbols. For the normal CP, the ratio of the CP length to the symbol length can be maintained at a constant value to keep the overhead caused by the CP constant, regardless of the subcarrier spacing. In other words, as the subcarrier spacing becomes narrower, the symbol length becomes longer, and the CP length can become longer accordingly. On the other hand, as the subcarrier spacing becomes wider, the symbol length becomes shorter, and the CP length can become shorter accordingly. The symbol length and the CP length can be inversely proportional to the subcarrier spacing.

[0061] In the 5G system, in order to meet various services and requirements, various frame structures can be supported by adjusting the subcarrier spacing. For example, in terms of the operating frequency band, the wider the subcarrier spacing, the more beneficial it is to recover from the phase noise in the high frequency band. For example, in terms of transmission time, when the subcarrier spacing becomes wider, the symbol length in the time domain is shortened, which results in a shorter time slot, and therefore, it is beneficial to support ultra-low latency services such as URLLC. For example, in terms of cell size, larger cells can be supported as the CP length becomes longer, and therefore, as the subcarrier becomes narrower, relatively larger cells can be supported. A cell is a concept indicating an area covered by a base station in mobile communications.

[0062] Subcarrier spacing, CP length, etc. are basic information for OFDM transmission and reception, and the base station and UE need to recognize the subcarrier spacing, CP length, etc. as common values ​​to achieve seamless transmission and reception.

[0063] Table 1 shows the relationship between the subcarrier spacing configuration μ, subcarrier spacing Δf, and CP length supported by the 5G system.

[0064] [Table 1]

[0065] μ <![CDATA[Δf=2 μ ×15[kHz]]]> Cyclic prefix 0 15 normal 1 30 normal 2 60 Normal, Extended 3 120 normal 4 240 normal

[0066] Table 2 shows the number of symbols per time slot for each subcarrier spacing configuration μ under normal CP. Number of time slots per frame and the number of time slots per subframe

[0067] [Table 2]

[0068]

[0069] Table 3 shows the number of symbols per time slot for each subcarrier spacing configuration μ in the extended CP case. Number of time slots per frame and the number of time slots per subframe

[0070] [Table 3]

[0071]

[0072] In the early stage of introducing the 5G system, at least coexistence or dual-mode operation with the conventional LTE or / and LTE-A system (hereinafter referred to as LTE / LTE-A) is expected. As a result, the conventional LTE / LTE-A system can provide stable system operation to the UE, and the 5G system can provide enhanced services to the UE. Therefore, the frame structure of the 5G system needs to include at least the frame structure or basic parameter set (subcarrier spacing = 15kHz) of the LTE / LTE-A system.

[0073] For example, when comparing a frame structure in which the subcarrier spacing configuration μ=0 (hereinafter referred to as frame structure A) and a frame structure in which the subcarrier spacing configuration μ=1 (hereinafter referred to as frame structure B), the subcarrier spacing and the RB size are increased to twice as large, and the slot length and the symbol length are reduced to twice as small in the frame structure B, compared to the frame structure A. In the case of the frame structure B, two slots can constitute one subframe, and 20 subframes can constitute one frame.

[0074] When the frame structure of the 5G system is normalized, the subcarrier spacing, CP length, time slot length, etc. as the basic parameter set can have an integer multiple relationship between them according to each frame structure to provide high scalability. In addition, in order to indicate a reference time unit independent of the frame structure, a subframe with a fixed length of 1ms can be defined.

[0075] The frame structure of the 5G system can be applied to correspond to various scenarios. In view of the cell size, when the CP length is longer, a larger cell can be supported, and therefore frame structure A can support relatively large cells compared to frame structure B. In view of the operating band, when the subcarrier spacing is wider, it is beneficial to recover from the phase noise of the high frequency band, and therefore frame structure B can support a relatively high operating frequency compared to frame structure A. In view of the service, since the shorter length time slot used as the basic time unit for scheduling is beneficial to support ultra-low latency services such as URLLC, frame structure B may be suitable for URLLC services compared to frame structure A.

[0076] Hereinafter, in the description of the present disclosure, uplink (UL) may refer to a radio link used to send data or control signals from a UE to a base station, and downlink (DL) may refer to a radio link used to send data or control signals from a base station to a UE.

[0077] In the initial access operation when the UE first accesses the system, the UE can establish DL time / frequency synchronization according to the synchronization signal sent by the base station through cell search, and can obtain the cell identity (ID). In addition, the UE can receive the physical broadcast channel (PBCH) by using the obtained cell ID, and can obtain the master information block (MIB) as basic system information from the PBCH. In addition, the UE can receive the system information block (SIB) sent by the base station to obtain the cell common transmission / reception related control information. The cell common transmission / reception related control information may include random access related control information, paging related control information, common control information for various physical channels, etc.

[0078] The synchronization signal is a reference signal for cell search, and a subcarrier spacing suitable for a channel environment such as phase noise can be applied per frequency band. Different subcarrier spacing can be applied to a data or control channel based on a service type to support various services as described above.

[0079] Figure 2 is a diagram illustrating a time domain mapping structure and a beam scanning operation of a synchronization signal according to an embodiment of the present disclosure.

[0080] To explain Figure 2 For this purpose, the following components can be defined.

[0081] - Primary Synchronization Signal (PSS): This signal is used as a reference for DL ​​time / frequency synchronization and provides some information about the cell ID.

[0082] - Secondary Synchronization Signal (SSS): This signal is used as a reference for DL ​​time / frequency synchronization and provides some residual information about the cell ID. In addition, this signal can be used as a reference signal for demodulating PBCH.

[0083] -Physical Broadcast Channel (PBCH): It provides the Master Information Block (MIB), which is the basic system information required for transmitting or receiving data channels and control channels of UEs. The Master Information Block (MIB) may include search space-related control information indicating radio resource mapping information of control channels, scheduling control information for a separate data channel for system information transmission, information as a frame unit index used as a timing reference (such as System Frame Number (SFN)), etc.

[0084] -Synchronization signal / PBCH block (SS / PBCH block or SSB): The SS / PBCH block is composed of N OFDM symbols and includes a combination of PSS, SSS, PBCH, etc. In the case of a system that applies beam scanning technology, the SS / PBCH block is the minimum unit to which beam scanning is applied. In a 5G system, N=4. The base station can send up to L SS / PBCH blocks, and the L SS / PBCH blocks are mapped within a half frame (0.5ms). In addition, the L SS / PBCH blocks are periodically repeated in units of a predetermined period P. The period P can be notified to the UE by the base station through signaling. In the absence of separate signaling for period P, the UE applies a predetermined default value. Each SS / PBCH block has an SS / PBCH block index from 0 to a maximum of L-1, and the UE can know the SS / PBCH block index through SS / PBCH detection.

[0085] refer to Figure 2 , beam scanning can be applied in units of SS / PBCH blocks according to the passage of time. Specifically, UE1 205 receives the SS / PBCH block at time t1 201 using a beam transmitted in direction #d0 203 by beamforming applied to SS / PBCH block #0. In addition, UE2 206 receives the SS / PBCH block at time t2 202 using a beam transmitted in direction #d4 204 by beamforming applied to SS / PBCH block #4. The UE can obtain the best synchronization signal from the base station through the beam transmitted in the direction where the UE is located. For example, it may be difficult for UE 1 205 to obtain time / frequency synchronization and basic system information from the SS / PBCH block through a beam transmitted in direction #d4 far away from the location of UE 1.

[0086] In addition to the initial access procedure, the UE may also receive the SS / PBCH block to determine whether the radio link quality of the current cell is maintained at a predetermined level or higher. In addition, in the procedure in which the UE performs handover from the current cell to the neighboring cell, the UE may receive the SS / PBCH block of the neighboring cell to determine the radio link quality of the neighboring cell and obtain time / frequency synchronization of the neighboring cell.

[0087] After the UE obtains the MIB and system information from the base station through the initial access procedure, the UE can perform a random access procedure to switch the link with the base station to a connected state (or RRC_CONNECTED state). After completing the random access procedure, the UE is switched to a connected state, and one-to-one communication is achieved between the base station and the UE. Figure 3 The random access procedure is described in detail in.

[0088] Figure 3A random access procedure according to an embodiment of the present disclosure is shown.

[0089] refer to Figure 3 , in the first operation 310 of the random access procedure, the UE may send a random access preamble to the base station. In the random access procedure, the random access preamble, which is the first message sent by the UE, may be referred to as message 1. The base station may measure the transmission delay value between the UE and the base station based on the random access preamble, and establish UL synchronization. In this case, the UE may randomly select a random access preamble to be used, which is in a random access preamble set given in advance by the system information. In addition, the initial transmit power of the random access preamble may be determined based on the path loss between the base station and the UE, wherein the path loss is measured by the UE. In addition, the UE may send a random access preamble by determining the transmit beam direction of the random access preamble based on a synchronization signal received from the base station.

[0090] In the second operation 320, the base station may send a UL transmission timing adjustment command to the UE based on the transmission delay value measured from the random access preamble received in the first operation 310. In addition, the base station may send a UL resource and a power control command to be used by the UE as scheduling information. Control information for a UL transmission beam of the UE may be included in the scheduling information.

[0091] If, in the second operation 320, the UE cannot receive a random access response (RAR) (or message 2) as scheduling information for message 3 from the base station within a predetermined period of time, the UE may again perform the first operation 310. In the case of performing the first operation 310 again, the UE increases the random access preamble transmission power and transmits the random access preamble (power ramp) through a predetermined operation, thereby increasing the random access preamble reception probability of the base station.

[0092] In the third operation 330, the UE may transmit UL data (message 3) including the UE ID of the UE itself to the base station via a UL data channel (Physical Uplink Shared Channel (PUSCH)) by using the UL resources allocated in the second operation 320. The transmission timing of the UL data channel for transmission of message 3 may follow the timing control command received from the base station in the second operation 320. In addition, the transmission power of the UL data channel for transmission of message 3 may be determined by considering the power ramp value and the power control command of the random access preamble received from the base station in the second operation 320. The UL data channel for transmission of message 3 may refer to the first UL data signal transmitted by the UE to the base station after the UE transmits the random access preamble.

[0093] In the fourth operation 340, when it is determined that the UE has performed random access without colliding with another UE, the base station may transmit data (message 4) including the ID of the UE that has transmitted UL data in the third operation 330 to the corresponding UE. When receiving the signal transmitted by the base station in the fourth operation 340 from the base station, the UE may determine that the random access is successful. In addition, the UE may transmit HARQ-ACK information indicating whether message 4 has been successfully received to the base station through a UL control channel (Physical Uplink Control Channel (PUCCH)).

[0094] If the base station fails to receive a data signal from the UE because the data transmitted by the UE in the third operation 330 collides with the data of another UE, the base station may no longer perform data transmission to the UE. Accordingly, when the UE fails to receive the data transmitted from the base station in the fourth operation 340 within a predetermined time period, it can be determined that the random access procedure has failed, and the process can start again from the first operation 310.

[0095] After successfully completing the random access procedure, the UE is switched to a connected state, and one-to-one communication can be performed between the base station and the UE. The base station can receive a report of UE capability information from the UE in the connected state, and can adjust the scheduling with reference to the UE capability information of the corresponding UE. The UE can inform the base station through the UE capability information whether the UE itself supports a predetermined function, the maximum allowed value of the function supported by the UE, etc. Accordingly, the UE capability information reported by each UE to the base station can be a different value for each UE.

[0096] As an example, the UE may report UE capability information including at least a portion of the following control information to the base station as the UE capability information.

[0097] -Control information related to the frequency bands supported by the UE.

[0098] -Control information related to the channel bandwidth supported by the UE.

[0099] -Control information related to the maximum modulation scheme supported by the UE.

[0100] -Control information related to the maximum number of beams supported by the UE.

[0101] -Control information related to the maximum number of layers supported by the UE.

[0102] -Control information related to CSI reporting supported by the UE.

[0103] -Control information related to whether the UE supports frequency hopping.

[0104] -Bandwidth related control information when Carrier Aggregation (CA) is supported, and / or

[0105] -Control information related to whether cross-carrier scheduling is supported when CA is supported.

[0106] Figure 4 A procedure for a UE to report UE capability information to a base station according to an embodiment of the present disclosure is shown.

[0107] refer to Figure 4 In operation 410, the base station 402 may send a UE capability information request message to the UE 401. In response to the request for UE capability information from the base station, the UE may send UE capability information to the base station in operation 420.

[0108] Hereinafter, a scheduling method in which a base station sends DL data to a UE or instructs the UE to send UL data will be described.

[0109] Downlink control information (DCI) is control information sent by a base station to a UE via DL, and may include DL data scheduling information or UL data scheduling information about a predetermined UE. In general, a base station may independently perform channel coding of DCI for each UE, and may then send the channel-coded DCI to each UE via a physical downlink control channel (PDCCH) which is a DL physical control channel.

[0110] The base station can operate for the UE to be scheduled by applying a certain DCI format determined depending on factors such as whether it is scheduling information about DL data (downlink assignment) or scheduling information about UL data (uplink grant), whether the DCI is for the purpose of power control.

[0111] The base station may send DL data to the UE through a physical downlink shared channel (PDSCH) which is a physical channel for DL ​​data transmission. The base station may inform the UE of scheduling information, such as a specific mapping position in the time domain and frequency domain of the PDSCH, a modulation scheme, HARQ-related control information, and power control information, through DCI related to scheduling information for DL ​​data in the DCI sent through the PDCCH.

[0112] The UE may transmit UL data to the base station through a physical uplink shared channel (PUSCH) which is a physical channel for UL data transmission. The base station may inform the UE of scheduling information, such as a specific mapping position in the time domain and frequency domain of the PUSCH, a modulation scheme, HARQ-related control information, and power control information, through DCI related to scheduling information for UL data in the DCI transmitted through the PDCCH.

[0113] The time-frequency resources to which the PDCCH is mapped are called the Control Resource Set (CORESET). The CORESET can be configured as all or part of the frequency resources of the bandwidth supported by the UE in the frequency domain. In the time domain, it can be configured as one or more OFDM symbols, which can be defined as the CORESET length (control resource set duration). The base station can configure one or more CORESETs to the UE through high-layer signaling (e.g., system information, master information block (MIB), radio resource control (RRC) signaling). Configuring a CORESET to the UE may mean providing information such as a CORESET identifier, a CORESET frequency position, and a CORESET symbol length. The information provided by the base station to the UE to configure the CORESET may include at least some information about the information included in Table 4.

[0114] [Table 4]

[0115]

[0116]

[0117] CORESET can be composed of RBs and time domain symbols. NRPDCCH can be composed of one or more control channel elements (Control Channel Element, CCE). A CCE can be composed of 6 resource element groups (Resource Element Group, REG), and REG can be defined as one RB during one OFDM symbol. In a CORESET, REGs can be indexed in time priority order starting from REG index 0 of the lowest RB in the first OFDM symbol of the CORESET.

[0118] PDCCH can be sent in an interleaved scheme and a non-interleaved scheme. The base station can configure the UE to send PDCCH in an interleaved or non-interleaved scheme based on CORESET through high-level signaling. Interleaving can be performed in units of REG bundles. REG bundles can be defined as a set of one or more REGs. The UE can determine the CCE to REG mapping scheme of the corresponding CORESET based on the interleaved or non-interleaved transmission scheme configured by the base station in the manner described in Table 5 below.

[0119] [Table 5]

[0120]

[0121]

[0122] The base station may indicate configuration information to the UE through signaling, such as the symbol to which the PDCCH is mapped in the time slot and the transmission period of the PDCCH.

[0123] Next, the search space of the PDCCH will be described.

[0124] The number of CCEs required to send PDCCH can be 1, 2, 4, 8 or 16 according to the aggregation level (AL), and different numbers of CCEs can be used for link adaptation of DL control channels. For example, in the case of AL=L, one DL control channel can be sent in L CCEs. In the absence of information about the DL control channel, the UE performs blind decoding to detect the signal. For blind decoding, a search space as a set of CCEs can be defined. The search space is a set of DL control channel candidates including CCEs that the UE should attempt to decode under a given AL. There are various ALs that bundle 1, 2, 4, 8 and 16 CCEs to form a bundle, and therefore the UE can have multiple search spaces. A search space set can be defined as a set of search spaces for all configured ALs.

[0125] The search space can be classified into a common search space (CSS) and a UE-specific search space (USS). A certain group of UEs or all UEs can monitor the CSS of the PDCCH to receive cell common control information, such as dynamic scheduling of the system information block (SIB) or paging messages. For example, the UE can receive scheduling assignment information about the PDSCH for system information reception by monitoring the CSS of the PDCCH. In the case of the CSS, since a certain group of UEs or all UEs should receive the PDCCH, the CSS can be defined as a set of preset CCEs. The UE can receive scheduling assignment information about the UE-specific PDSCH or PUSCH by monitoring the USS of the PDCCH. The USS can be UE-specifically defined by a function of the UE identity (ID) and various system parameters.

[0126] The base station may configure the configuration information about the search space of the PDCCH for the UE through high-level signaling (e.g., SIB, MIB, or RRC signaling). For example, the base station may configure the number of PDCCH candidate groups for each aggregation level L, the monitoring period of the search space, the monitoring timing in units of symbols in the time slot of the search space, the search space type (CSS or USS), the combination of the DCI format and RNTI (Radio Network Temporary Identity) to be monitored in the search space, and the CORESET index to be monitored in the search space. For example, the parameters for the PDCCH search space may include the information described in Table 6 below.

[0127] [Table 6]

[0128]

[0129]

[0130]

[0131]

[0132] According to the configuration information, the base station may configure one or more search space sets for the UE. According to an embodiment, the base station may configure search space set 1 and search space set 2 for the UE. In search space set 1, the UE may be configured to monitor DCI format A scrambled with X-RNTI in the CSS, and in search space set 2, the UE may be configured to monitor DCI format B scrambled with Y-RNTI in the USS.

[0133] According to configuration information, one or more search space sets may exist in a CSS or a USS. For example, search space set #1 and search space set #2 may be configured as a CSS, and search space set #3 and search space set #4 may be configured as a USS.

[0134] In the CSS, the UE may monitor the following combinations of DCI formats and RNTIs, but the present disclosure is not limited to the following examples.

[0135] -DCI format 0_0 / 1_0, whose CRC is scrambled by C (Cell)-RNTI, CS (Configured Scheduling)-RNTI, SP (Semi-Persistent)-CSI-RNTI, RA (Random Access)-RNTI, TC (Temporary Cell)-RNTI, P (Paging)-RNTI, SI (System Information)-RNTI

[0136] -DCI format 2_0, whose CRC is scrambled by SFI (Slot Format Indication)-RNTI

[0137] -DCI format 2_1, whose CRC is scrambled by INT (Interruption)-RNTI

[0138] -DCI format 2_2, whose CRC is scrambled by TPC (Transmit Power Control)-PUSCH-RNTI, TPC-PUCCH-RNTI

[0139] -DCI format 2_3, whose CRC is scrambled by TPC-SRS (Sounding Reference Signal)-RNTI

[0140] In the USS, the UE may monitor the following combinations of DCI formats and RNTIs. The present disclosure is not limited to the following examples.

[0141] -DCI format 0_0 / 1_0, whose CRC is scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0142] -DCI format 1_0 / 1_1, whose CRC is RNTI scrambled by C-RNTI, CS-RNTI, TC-RNTI can be defined and used as follows.

[0143] Cell RNTI (C-RNTI): used for UE-specific PDSCH or PUSCH scheduling purposes

[0144] Temporary Cell RNTI (TC-RNTI): used for UE-specific PDSCH scheduling purposes

[0145] Configured Scheduling RNTI (CS-RNTI): used for semi-statically configured UE-specific PDSCH scheduling purposes

[0146] Random Access RNTI (RA-RNTI): used for PDSCH scheduling purposes during the random access phase

[0147] Paging RNTI (P-RNTI): used for PDSCH scheduling purposes for paging transmissions

[0148] System Information RNTI (SI-RNTI): used for PDSCH scheduling purposes for system information transmission

[0149] Interrupt RNTI (INT-RNTI): used to indicate whether PDSCH is punctured

[0150] Transmit Power Control RNTI for PUSCH (TPC-PUSCH-RNTI): used to indicate the purpose of the power control command for PUSCH

[0151] Transmit Power Control RNTI for PUCCH (TPC-PUCCH-RNTI): used to indicate the purpose of the power control command for PUCCH

[0152] Transmit Power Control RNTI for SRS (TPC-SRS-RNTI): used to indicate the purpose of the power control command for SRS

[0153] The above DCI format may follow the definition shown in Table 7 below.

[0154] [Table 7]

[0155]

[0156]

[0157] The search space for aggregation level L in CORESET p and the search space set s can be expressed by equation (1).

[0158] [Equation 1]

[0159]

[0160] -L: aggregation level

[0161] -n CI : Carrier index

[0162] -N CCE,p : Controls the total number of CCEs in resource set p

[0163] - Time slot index

[0164] - Number of PDCCH candidates at aggregation level L

[0165] - Index of PDCCH candidates at aggregation level L

[0166] -i=0,...,L-1

[0167] -

[0168] Y p，-1 =n RNTI ≠0,

[0169] For pmod3 = 0, A p =39827;

[0170] For pmod3 = 1, A p =39829;

[0171] For pmod3 = 2, A p =39839;

[0172] And D=65537.

[0173] -n RNTI :UE ID

[0174] The value may correspond to 0 in the case of CSS.

[0175] The value may correspond to a value that changes according to UE ID (C-RNTI or ID configured by the base station for the UE) and a time index in the case of USS.

[0176] As a measure to support ultra-high-speed data services, the data rate can be increased by using a spatial multiplexing method using multiple transmit antennas and receive antennas. In general, the number of power amplifiers (PA) required increases in proportion to the number of transmit antennas equipped in the base station or UE. The maximum output of the base station and the UE is determined by the characteristics of the power amplifier, and the maximum output of the base station generally varies depending on the size of the cell covered by the base station. The maximum output can usually be expressed in dBm. For example, the maximum output of a UE is usually 23dBm or 26dBm.

[0177] As an example of a commercial 5G base station, the base station is equipped with 64 transmit antennas and corresponding 64 power amplifiers in the 3.5GHz frequency band, and can operate in a bandwidth of 100MHz. As a result, the energy consumption of the base station increases in proportion to the output of the power amplifier and the operating time of the power amplifier. Compared with LTE base stations, 5G base stations have a relatively high operating frequency band, so they have the characteristics of wide bandwidth and multiple transmit antennas. These characteristics have the effect of increasing the data rate, but at the expense of increasing the energy consumption of the base station. Therefore, the more base stations there are in the mobile communication network, the greater the energy consumption of the entire mobile communication network.

[0178] As described above, the energy consumption of a base station may be greatly affected by the operation of a power amplifier. Since a power amplifier is involved in the base station transmission operation, the downlink (DL) transmission operation of the base station is highly related to the energy consumption of the base station. Relatively speaking, the uplink (UL) reception operation of the base station may not account for a large proportion of the energy consumption of the base station. The physical channels and physical signals transmitted by the base station in the DL are as follows.

[0179] - Physical Downlink Shared Channel (PDSCH): A DL data channel that includes data to be sent to one or more UEs

[0180] - Physical Downlink Control Channel (PDCCH): A DL control channel that includes scheduling information for PDSCH and Physical Uplink Control Channel (PUSCH). Alternatively, control information such as slot format and power control commands can be sent using only PDCCH without scheduling PDSCH or PUSCH. Scheduling information includes resource information to which PDSCH or PUSCH is mapped, HARQ-related information, power control information, etc.

[0181] - Physical Broadcast Channel (PBCH): A DL broadcast channel that provides the Master Information Block (MIB), which is basic system information required for transmitting and receiving data channels and control channels of UEs.

[0182] - Primary Synchronization Signal (PSS): This signal is used as a reference for DL ​​time / frequency synchronization and provides some information about the cell ID.

[0183] - Secondary Synchronization Signal (SSS): This signal is used as a reference for DL ​​time and / or frequency (hereinafter referred to as time / frequency) synchronization and provides some residual information about the cell ID.

[0184] - Demodulation Reference Signal (DM-RS): This is a reference signal used by the UE for channel estimation for each of PDSCH, PDCCH and PBCH.

[0185] - Channel State Information Reference Signal (CSI-RS): This is a DL signal used as a reference for measuring a DL channel state of a UE.

[0186] -Phase-tracking Reference Signal (PT-RS): This is a DL signal used for phase tracking.

[0187] From the perspective of base station energy saving, when the base station stops DL transmission operation, this causes the power amplifier operation to stop, which can increase the energy saving effect of the base station. Additional energy saving is possible by reducing the operation of other base station equipment including baseband equipment and power amplifiers. Similarly, even if UL reception operation accounts for a relatively small part of the total energy consumption of the base station, additional energy saving effects can be achieved if the UL reception operation can be stopped.

[0188] The DL transmission operation of the base station is basically determined by the DL traffic volume. For example, if there is no data to be sent to the UE via DL, the base station does not need to send PDSCH and PDCCH for scheduling PDSCH. Alternatively, if the transmission can be delayed for a period of time (such as because the data is not sensitive to transmission delay), the base station may not send PDSCH or / and PDCCH. For the convenience of the following explanation, the method for reducing the energy consumption of the base station by not sending or appropriately adjusting PDSCH or / and PDCCH associated with data traffic can be referred to as "base station energy saving method 1-1".

[0189] In contrast, physical channels and physical signals such as PSS, SSS, PBCH and CSI-RS have the characteristic of being repeatedly transmitted at a predetermined agreed period, regardless of the data transmission to the UE. Therefore, even if the UE does not receive data, it can continuously update DL time / frequency synchronization, DL channel status, radio link quality, etc. In other words, PSS, SSS, PBCH and CSI-RS must be sent in DL, regardless of the DL data service, and thus cause base station energy consumption. Therefore, base station energy saving can be achieved by adjusting the transmission of signals that are not related to (or have low correlation with) data services to occur less frequently (hereinafter referred to as "base station energy saving method 1-2").

[0190] By using "Base Station Energy Saving Method 1-1" or "Base Station Energy Saving Method 1-2", the energy saving effect of the base station can be maximized by stopping or minimizing the operation of the base station's power amplifier and the operation of related RF equipment, baseband equipment, etc. during the time period when the base station does not perform DL transmission.

[0191] Alternatively, the energy consumption of the base station can be reduced by turning off some antennas or power amplifiers of the base station (hereinafter referred to as "base station energy saving method 2"). In this case, as a countermeasure to the energy saving effect of the base station, adverse effects such as reduced cell coverage or reduced throughput may occur. For example, as described above, there may be a base station equipped with 64 transmit antennas and corresponding 64 power amplifiers in the 3.5 GHz band, and operating in a bandwidth of 100 MHz. In order to save energy for such a base station, when only 4 transmit antennas and 4 power amplifiers are activated for a certain time period and the remaining antennas and power amplifiers are turned off, the base station energy consumption during the time period is reduced to approximately 1 / 16 (= 4 / 64). When only 4 transmit antennas and 4 power amplifiers are activated for a certain time period and the remaining antennas and power amplifiers are turned off, due to the reduction in maximum transmit power and beamforming gain, it becomes difficult to achieve cell coverage and throughput assuming the existing 64 antennas and power amplifiers.

[0192] In the following description, in order to distinguish from normal base station operation, the base station mode applying the base station energy saving operation is referred to as the base station energy saving mode (ES mode), and the base station mode applying the normal base station operation is referred to as the base station normal mode (normal mode). However, the use of these terms does not limit the technical scope of the present disclosure.

[0193] As another solution to support ultra-high-speed data services, the 5G system can support ultra-wide bandwidth signal transmission and reception of tens to hundreds of MHz or several GHz. Ultra-wide bandwidth signal transmission and reception can be supported by a single component carrier (CC) or by carrier aggregation (CA) technology that combines multiple component carriers. In the case where a mobile communication operator cannot ensure that a frequency with sufficient bandwidth can provide ultra-high-speed data services using a single component carrier, carrier aggregation technology can combine corresponding component carriers with relatively small bandwidth sizes to increase the total frequency bandwidth, thereby achieving ultra-high-speed data services.

[0194] Figure 5 The relationship between frequency band, coverage and bandwidth according to an embodiment of the present disclosure is shown.

[0195] As mentioned above, the frequency bands used by 5G systems are in a wide range from hundreds of MHz to tens of GHz. Figure 5 , coverage and frequency bandwidth may vary depending on each of the low frequency band 501, the medium frequency band 502, the high frequency band 503, and the ultra-high frequency band 504. The lower the frequency band, the greater the coverage due to the relatively small path loss; and the higher the frequency band, the smaller the coverage due to the relatively high path loss. In the low frequency band, the frequency that can be used for mobile communication is relatively small, and the bandwidth is small; while in the high frequency band, it is relatively easy to ensure a wide bandwidth frequency, making it suitable for ultra-high-speed data services.

[0196] As mobile communication systems evolve, efforts are being made to discover and utilize new frequency bands. For example, although it is still in the early stages of discussion, the 6th generation (6G) mobile communication system, which is the next generation of mobile communication systems, is also considering using terahertz (THz, i.e. 10 12 Hz) frequency band as one of the candidate frequencies. In general, a mobile communication operator ensures multiple frequency bands to provide mobile communication services to users. For example, a mobile communication operator can combine the existing ensured frequency bands of the LTE system and the newly ensured frequency bands of the 5G system to operate a system combining LTE and 5G. As another example, a mobile communication operator can ensure the frequency bands of the 5G system across multiple frequency bands, and then provide mobile communication services via 5G CA by combining the frequencies of the multiple frequency bands. As described above, since characteristics such as coverage and bandwidth vary depending on the frequency band, mobile communication services that combine multiple frequency bands rather than mobile communication services that depend on a single frequency band are becoming more and more active.

[0197] Figure 6 An example of a base station deployment scenario according to an embodiment of the present disclosure is shown.

[0198] refer to Figure 6, the carrier can be composed of a carrier operating at frequency F1 (hereinafter referred to as "macro cell" 601 for ease of explanation) and carriers operating at frequency F1 or F2 (hereinafter referred to as "small cells" 602, 603, 604, 605, 606) (e.g., F1 < F2). It is assumed that the "macro cell" has a relatively high maximum output to provide wide cell coverage, while the "small cells" have a relatively low maximum output to provide limited cell coverage. Figure 6 The size of the circles shown can represent the coverage size that each carrier can provide. Multiple "small cells" can coexist within the coverage of the "macro cell". The "macro cell" and the "small cells" can be connected to each other either wired or wirelessly to achieve smooth cooperation. In the present disclosure, the base station can be a combination of the "macro cell" and the "small cells", or can be implemented as separate base stations for the "macro cell" and the "small cells" respectively. In the case where the "macro cell" and the "small cells" are implemented as one base station, both the "macro cell" and the "small cells" can be referred to as transmission reception points (TRP).

[0199] Figure 7 Another example of a base station deployment scenario according to an embodiment of the present disclosure is shown.

[0200] Reference Figure 7 , a carrier bundling system is shown, in which a carrier operating at frequency F1 (cell 1) and a carrier operating at frequency F2 (cell 2) are combined (e.g., F1 ≠ F2). Figure 7 An example of applying carrier bundling by one base station is shown. Different from the situation in Figure 6 , it shows a situation where the cell coverages provided by the corresponding carriers are similar to each other.

[0201] In the present disclosure, in order to reduce the power consumption of the base station, the transmission power of the signal transmitted by the base station can be adjusted. That is, when the base station transmission power in the normal mode of the base station is P normal , and the base station transmission power in the energy-saving mode of the base station is P energysaving , the transmission power of the base station transmitted signal can be adjusted to satisfy the relationship of P normal >P energysaving . The above "base station energy-saving method 2" can be regarded as a special case where P energysaving = 0. For example, the units of P normal and P energysaving can be expressed in Watt. This reduction in transmission power can be achieved by the above "base station energy-saving method 1-1", "base station energy-saving method 1-2" and "base station energy-saving method 2". However, it should be noted that the present disclosure is not limited to the base station energy-saving methods presented above.

[0202] exist Figure 6 or Figure 7 In the case of the scenario in which the base station is connected to the network, the base station can reduce the energy consumption of the base station by adjusting the transmission power of the base station signal transmitted in at least one of the multiple cells constituting the system. Figure 6 In the case of a "small cell", the base station can maintain cell coverage through the "macro cell" and reduce the base station energy consumption of the "small cell" by adjusting the transmission power of at least one "small cell" and maintaining the transmission power of the "macro cell" as it is. Figure 7 In this case, the base station can maintain cell coverage and reduce base station energy consumption by adjusting the transmission power of cell 2 and maintaining the transmission power of cell 1 as it is.

[0203] The transmit power may be expressed as a power spectral density (PSD) linked to the bandwidth. For example, the unit of PSD may be generally expressed as Watt / Hz and may mean power per unit bandwidth. The transmission bandwidth means the bandwidth occupied by the signal transmitted by the base station and may be expressed in MHz. Energy Per Resource Element (EPRE) may be used as a concept similar to PSD. EPRE means energy per RE. For example, EPRE may be expressed in dBm.

[0204] The present disclosure proposes a method for configuring parameters for receiving channel state information (CSI) reports from UE and indicating them to UE when entering a mode for reducing energy consumption of a base station. Specifically, the base station can allocate transmission resources for signals (e.g., such as CSI-RS) for CSI measurement of the UE, and send them to the UE in a periodic and aperiodic manner. The signal for CSI measurement can use not only CSI-RS, but also SSB. For example, if the transmit power is reduced as a base station energy saving method, but many CSI-RS resources are allocated and transmissions for CSI-RS resources occur frequently, this will result in energy consumption at the base station, thereby halving the energy saving effect. As another example, when a part of the power amplifier (PA) of the base station antenna is turned off as a base station energy saving method, the number of CSI-RS ports for channel measurement needs to be adjusted and indicated accordingly. Most importantly, although the power consumption of the base station can be reduced by applying the base station energy saving method, the cell throughput and coverage may be reduced. To overcome this, it is important for the base station to receive CSI reports from the UE, and based on the CSI reports, it can decide whether to enter a mode for energy saving for the base station or use more power for cell throughput and coverage. However, these base station transmission methods should be able to be adjusted at short intervals (such as transmission time intervals (TTIs)) and at the symbol level so that the transmission method suitable for the base station situation can be quickly applied. In this way, a balance can be achieved between base station energy saving and improving cell throughput and coverage.

[0205] In the present disclosure, a method is proposed in which, when the base station adjusts transmission parameters to reduce energy consumption, the base station configures CSI-related parameters and indicates the parameters to the UE, so that the UE can measure CSI and appropriately report the CSI measurement to the base station.

[0206] In order for the base station to receive CSI reports from the UE, CSI resource configuration and CSI report configuration must be performed. The CSI resource configuration may consist of a resource set configuration and a resource configuration included in the resource set. The reference signal for CSI measurement may be sent through the CSI resource configuration. In addition, the UE may report the measured CSI to the base station through the CSI report configuration.

[0207] Fig. 8A and Figure 8B is a diagram for explaining a CSI resource configuration method according to an embodiment of the present disclosure.

[0208] refer to Fig. 8A and Figure 8B, the CSI resource configuration may consist of a resource set configuration and a resource configuration included in the resource set. A maximum of X CSI resource configurations may be configured (eg, X=112). The number of resource configurations included in each resource set may be configured to be at most Y (eg, Y=64).

[0209] refer to Fig. 8A , a CSI resource configuration may include a resource set configuration. This configuration may be limited to configurations corresponding to periodic CSI and semi-persistent CSI. Figure 8B , multiple resource set configurations can be included in one CSI resource configuration. This configuration can be limited to configurations corresponding to non-periodic CSI. In addition, in a similar Figure 8B In this case, the maximum number of resource set configurations that can be included in each CSI resource configuration can be configured as S (for example, S=16).

[0210] Fig. 9 Relevant parameters included in the CSI resource configuration according to an embodiment of the present disclosure are shown.

[0211] refer to Fig. 9, CSI-related parameters may include CSI report configuration (CSI-ReportConfig 8400), CSI measurement configuration (CSI-MeasConfig 8500) and CSI resource configuration (CSI-ResourceConfig 8000). CSI resource configuration may be performed via CSI-ResourceConfig 8000. Reference signals for CSI measurement may be sent via CSI resource configuration. The type of CSI resource may be determined via CSI resource configuration. In other words, csi-RS-ResourceSetList 8002 may be indicated, which is a resource set configuration for determining the type of CSI resource via CSI resource configuration. Specifically, resource set configuration 8002 may include NZP-CSI-RS-ResourceSet 8100 for channel and interference measurement, CSI-IM-ResourceSet 8300 for interference measurement, and CSI-SSB-ResourceSet 8200 for channel measurement. Here, NZP-CSI-RS-ResourceSet 8100 or CSI-IM-ResourceSet 8300 may be performed by CSI-RS transmission as a reference signal, and CSI-SSB-ResourceSet 8200 may be performed by a synchronization signal block (SSB). CSI-ResourceConfig 8000 as a CSI resource configuration may include csi-ResourceConfigId 8001 as a corresponding ID, bwp-Id 8003 as an ID of a bandwidth part (BWP) through which CSI resources are transmitted, and resourceType 8004 indicating whether transmission of CSI is aperiodic (AP), semi-persistent (SP), or periodic (P) (i.e., time domain behavior of resource configuration). CSI-SSB-ResourceSet 8200 may include CSI-SSB-ResourceSetID 8210 and CSI-SSB-Resourcelist 8220. CSI-IM-ResourceSet 8300 may include CSI-IM-ResourceSetID 8310 and CSI-IM-Resources 8320. CSI-IM-Resources 8320 may include CSI-IM-ResourceID 8321, CSI-IM-ResourceElementPattern 8322, freqband 8323, and periodicityAndOffset8324.

[0212] Describe in more detail Fig. 9NZP-CSI-RS-ResourceSet 8100 in the resource set configuration in . NZP-CSI-RS-ResourceSet 8100 may include nzp-CSI-ResourceSetId 8110 as the corresponding ID, nzp-CSI-RS-Resources 8120 for resource configuration, Repetition8130 for indicating whether to repeat the transmission of resources, aperiodicTriggeringOffset 8140 for indicating the time position of the aperiodic CSI resource set, trs-Info 8150 as the tracking reference signal (TRS) related configuration, etc.

[0213] In addition, specific information on how to transmit CSI-RS can be configured through nzp-CSI-RS-Resources 8120 as a resource configuration via 8121 to 8127. The nzp-CSI-RS-Resources 8120 may include nzp-CSI-RS-ResourceID 8121, resourceMapping 8122, powerControlOffset 8123, powerControlOffsetSS 8124, scramblingID 8125, qcl-InfoPeriodicCSI-RS 8126, periodicityAndOffset 8127. In particular, the number of CSI-RS ports 8122-2 and the configuration of related parameters may refer to resourceMapping 8122 in the NZP-CSI-RS-Resource 8120 configuration. Specifically, frequencyDomainAllocation 8122-1 is a parameter indicating the frequency RE position within the RB where the CSI-RS is transmitted. firstOFDMSymbolInTimeDomain 8122-3 is a parameter indicating the symbol position within the RB in which the CSI-RS is transmitted. cdm-Type 8122-4 is a parameter indicating which code, for example, among {noCDM, fd-CDM2, cdm4-FD2-TD2, cdm8-FD2-TD4} is applied to the CSI-RS. Density 8122-5 is a parameter indicating the density of the CSI-RS measured in RE / port / PRB, and can be configured as, for example, one of the values ​​{0.5, 1, 3}. freqBand 8122-6 is a parameter indicating the frequency domain in which the CSI-RS is transmitted.

[0214] Specifically, methods 1 to 5 propose a method for a base station to configure CSI-related parameters to reduce energy consumption. Method 6 proposes a method for a base station to indicate the number of CSI-RS ports and related parameters to a UE to reduce energy consumption. Method 7 proposes a method for a base station to indicate to a UE the frequency domain in which a CSI-RS is sent to reduce energy consumption. Method 8 proposes a method for a base station to indicate to a UE the period and offset value of sending a CSI-RS to reduce energy consumption. Method 9 proposes a method for measuring and reporting CSI during the operation process of reducing energy consumption of a base station.

[0215] The method proposed in the present disclosure can be applied to the case where transmission parameters are adjusted at short time intervals for power saving of base stations and cell throughput and coverage management.

[0216] One or more methods and / or embodiments proposed in this disclosure may be used in combination with each other.

[0217] <Method 1>

[0218] A method 1 for configuring CSI-related resources and parameters to reduce energy consumption of a base station according to an embodiment of the present disclosure will be described.

[0219] The base station may activate / deactivate the CSI-related parameters configured using RRC through MAC-CE and / or DCI. The CSI-related parameters configured using RRC may correspond to Fig. 9 In addition, method 1 may be limited to parameter configurations corresponding to periodic or semi-persistent CSI.

[0220] Legacy UEs (UEs that cannot interpret newly introduced signaling) may not be able to receive CSI-related parameters changed according to method 1. Therefore, a method for supporting legacy UEs by frequency differentiation may be considered. For example, in bandwidth part (BWP) A, CSI-related parameters configured using RRC as before are applied to support legacy UEs, and in BWP B, CSI-related parameters configured using RRC may be activated / deactivated for new UEs (UEs that can interpret newly introduced signaling) through MAC-CE and / or DCI. According to the above method 1, the base station may indicate CSI resources and reporting configurations to the UE to reduce the energy consumption of the base station, and the UE may report CSI to the base station accordingly.

[0221] Specifically, the base station can configure up to X (e.g., X=112) CSI resource configurations of UEs within the base station coverage through RRC. However, as the number of CSI resource configurations of the base station approaches X, the amount of CSI resources increases, and if transmissions for these resources occur frequently, it will cause energy consumption of the base station.

[0222] Therefore, when the base station is in energy-saving mode, the amount of CSI resources sent by the base station can be reduced by deactivating the CSI resources configured by RRC. In contrast, when the base station is not in energy-saving mode, the deactivated CSI resources can be reactivated to increase the amount of CSI resources and better receive CSI reports from the UE. More specifically, the following alternatives can be regarded as methods for activating / deactivating CSI resource configurations configured by RRC. It should be noted that the present disclosure is not limited to the following alternatives. In addition, in the case of considering one or more of the following alternatives, which alternative to use can be configured by RRC.

[0223] *Alternative solution 1: AC-CE activation / deactivation

[0224] ** In the case of alternative 1, where there are X resource configurations, which resource has been activated / deactivated may be indicated by the MAC CE through a bitmap of X bits. However, note that the signaling method in the present disclosure is not limited to a bitmap.

[0225] *Alternative 2: MAC-CE+DCI activation / deactivation

[0226] ** In the case of alternative 2, in the case of X resource configurations, which resource has been activated / deactivated can be indicated by the MAC CE through an X-bit bitmap. Then, for Y (≤ X) resource configurations activated by the MAC-CE, the resource activated by the DCI can use Y bits or Note that the signaling method in the present disclosure is not limited to the method presented above. Fig.10 An example of this is shown in .

[0227] Fig.10 An example of activating / deactivating CSI resources via MAC CE and DCI according to an embodiment of the present disclosure is shown.

[0228] refer to Fig.10 , X CSI resources can be configured through RRC, which are CSI resource #0 to CSI resource #(X-1). Among them, CSI resource #1, CSI resource #3 and CSI resource #(X-1) can be activated through MAC-CE. In addition, the activation of CSI resource #1 can be indicated by DCI.

[0229] In the case where a bitmap is used by DCI to indicate Y resources activated by MAC-CE, one or more activated resources may be indicated, but When the bit is used to indicate, only one activated resource can be indicated.

[0230] *Alternative 3: DCI activation / deactivation

[0231] ** In the case of alternative 3, where there are X resource configurations, the resource activated via DCI can use X bits or The bitmap of bits is indicated to indicate which of these resources has been activated / deactivated. Note that the present disclosure is not limited to the methods presented above as signaling methods.

[0232] In case of activating / deactivating the CSI resource configuration through MAC-CE or DCI related to the energy-saving operation of the above-mentioned base station, the resource set configuration in the CSI resource configuration or the resource configuration included in the resource set configuration may be all activated / deactivated together.

[0233] In an embodiment according to the above-mentioned method 1, a method for activating / deactivating the CSI resource configuration configured by RRC through MAC-CE or DCI is proposed, but the present disclosure is not limited to this. For example, the resource set configuration configured by RRC or the resource configuration included in the resource set and the CSI report configuration, etc. can be activated / deactivated through MAC-CE or DCI related to the energy-saving operation of the base station. For example, in the case where the TRS is configured to be sent as {true} in the resource set configuration of the CSI resource configuration, the TRS can be turned on / off for transmission by activation / deactivation via MAC-CE or DCI. In the case of activating / deactivating the corresponding function through DCI, 1-bit information for turning on / off TRS for transmission can be included in the DCI, and in the case where the TRS is configured to be sent as {false} in RRC, the corresponding bit in the DCI can be configured as a zero bit.

[0234] <Method 2>

[0235] Method 2 for configuring CSI-related resources and parameters to reduce energy consumption of a base station according to an embodiment of the present disclosure will be described.

[0236] Depending on whether the base station is in energy-saving mode, the CSI-related configuration can be distinguished in RRC. The CSI-related parameters configured by RRC may correspond to the CSI-related parameters related to Fig. 9 Furthermore, Method 2 may be limited to parameter configurations corresponding to periodic or semi-persistent CSI.

[0237] According to Method 2, when the base station is in the energy-saving mode, traditional UEs may not be able to receive CSI-related configurations configured in RRC. Therefore, methods for supporting traditional UEs, for example, by frequency differentiation, can be considered. For example, in BWP A, the same CSI-related configurations configured by RRC as before are applied to support traditional UEs, and in BWP B, the CSI-related configurations configured by RRC can be applied to new UEs when the base station is in the energy-saving mode. According to the above Method 2, the base station can indicate CSI resources and reporting configurations to the UE to reduce the energy consumption of the base station, and the UE can report CSI to the base station accordingly.

[0238] Specifically, when the base station is not operating in the energy-saving mode, the base station can configure up to X (for example, X = 112) CSI resource configurations for UEs within the base station coverage through RRC configuration. As the CSI resource configuration of the base station approaches X, the amount of CSI resources increases, and if transmissions for these resources occur frequently, the energy consumption of the base station will inevitably occur. Therefore, Method 2 is a method for operating the CSI resource configuration configured by RRC separately for the case where the base station is not in the energy-saving mode and the case where the base station is in the energy-saving mode.

[0239] More specifically, when the base station is in the energy-saving mode, the number of CSI resource configurations configured by RRC can be limited to at most Y (for example, Y < X, for example, Y = 32). In this case, the above Method 1 can be applied, and a method for activating / deactivating the CSI resource configuration configured by RRC when the base station is in the energy-saving mode can be additionally applied.

[0240] Fig.11A and Fig. 11B shows an example of a CSI resource configuration method according to an embodiment of the present disclosure.

[0241] Reference Fig.11A and Fig. 11B will describe the CSI resource configuration method according to the above Method 2. Referring to Fig.11A when the base station is not operating in the energy-saving mode, the number of CSI resource configurations can be configured up to X at most and operate. In contrast, referring to Fig. 11B when the base station is operating in the energy-saving mode, the number of CSI resource configurations can be configured up to Y (for example, Y < X) at most and operate.

[0242] In addition to the above CSI resource configuration, in the case where the base station is not in the energy-saving mode and in the case where the base station is in the energy-saving mode, the resource set configuration within the CSI resource configuration configured by RRC or the resource configuration included in the resource set can be configured separately. In addition, the CSI reporting configuration configured by RRC can also be distinguished.

[0243] <Method 3>

[0244] Method 3 for configuring CSI-related resources and parameters to reduce energy consumption of a base station according to an embodiment of the present disclosure will be described.

[0245] Depending on whether the base station is in energy-saving mode, some CSI-related parameters configured through RRC may be configured differently. The CSI-related parameters configured through RRC may correspond to Fig. 9 Furthermore, Method 3 may be limited to parameter configurations corresponding to periodic or semi-persistent CSI.

[0246] The above method 2 is a method for separately configuring CSI resource configuration, resource set configuration, resource configuration, CSI report configuration, etc. configured by RRC depending on whether the base station is in energy-saving mode. However, method 3 is a method for configuring only some parameters in CSI resource configuration, resource set configuration, resource configuration, CSI report configuration, etc. configured by RRC differently depending on whether the base station is in energy-saving mode. In the case where the base station is in energy-saving mode, specific parameter values ​​in CSI resource configuration and CSI report configuration can be configured in consideration of the energy-saving mode of the base station. In addition, in the case of energy-saving mode, specific parameters in CSI resource configuration and CSI report configuration may not be used, or new parameters may be added. For example, in the resource set configuration in the CSI resource configuration, TRS may be configured as {false} so that TRS may not be sent. As another example, in the resource configuration included in the resource set, unlike the case where it is not in energy-saving mode, CSI-RS period / offset, the number of CSI-RS ports, the frequency domain in which CSI-RS is sent, etc. may be configured as different values ​​in consideration of energy-saving mode. According to the above method 3, the base station can indicate CSI resources and reporting configuration to the UE to reduce base station energy consumption, and the UE can report CSI to the base station accordingly.

[0247] Fig.12 Another example of a method for configuring CSI resources according to an embodiment of the present disclosure is shown.

[0248] refer to Fig.12 , describes a method for configuring CSI resources according to the above method 3. Fig.12 , shows an example of configuring parameters for CSI-RS period and number of CSI-RS ports in each resource (resource #X) (X is a resource ID, e.g., X=0, 1, 2, ...). Fig. 9The same periodicityAndOffset (CSI-ResourcePeriodicityAndOffset) 8127 and related parameters of nrofPorts 8122-2 in the NZP-CSI-RS-Resource 8120 configuration. According to Method 3, depending on whether the base station is in the energy-saving mode, the values of the corresponding parameters can be configured as two different values. Specifically, when the base station is not in the energy-saving mode, the CSI-RS period can be configured as A, or when the base station is in the energy-saving mode, the CSI-RS period can be configured as A' (e.g., A < A'). As another example, when the base station is not in the energy-saving mode, the number of CSI-RS ports can be configured as B, or when the base station is in the energy-saving mode, the number of CSI-RS ports can be configured as B' (e.g., B > B').

[0249] In Method 3, in the case of differently configuring some CSI-related parameters configured by RRC depending on whether the base station is in the energy-saving mode, it can be determined which parameter to apply to the UE depending on whether the base station is configured as the energy-saving mode. The base station can explicitly indicate to the UE whether the base station is in the energy-saving mode through configuration, or can indicate it in an implicit way. The method by which the base station indicates to the UE whether the base station is in the energy-saving mode is not limited to the specific method in this disclosure.

[0250] According to Method 3, in the case where the base station is in the energy-saving mode, traditional UEs may not be able to interpret some CSI-related parameters configured in the RRC. Therefore, for example, a method for supporting traditional UEs by frequency differentiation can be considered. For example, in BWPA, the existing CSI-related parameters configured by RRC are applied to the case where it is not in the energy-saving mode to support traditional UEs, and in BWP B, the CSI-related parameters configured by RRC can be applied to new UEs considering that the base station is in the energy-saving mode.

[0251] <Method 4>

[0252] A method for configuring CSI-related resources and parameters to reduce the energy consumption of a base station according to an embodiment of the present disclosure will be described.

[0253] Method 4-1 is such a method that among the CSI-related configurations configured by RRC, only the configurations corresponding to non-periodic CSI are activated when the base station is in the energy-saving mode, and all configurations corresponding to periodic or semi-persistent CSI are deactivated.

[0254] Method 4-2 is a method in which, among the CSI-related parameters configured through RRC, only the configurations corresponding to aperiodic CSI and semi-persistent CSI are activated when the base station is in energy saving mode, and all configurations corresponding to periodic CSI are deactivated.

[0255] Since the configuration corresponding to the periodic CSI is deactivated according to the above method 4-1 or method 4-2, at least the periodic CSI-RS transmission or periodic CSI report is deactivated, the amount of CSI resources is reduced and the corresponding transmission is prevented from occurring frequently, thereby achieving the effect of energy saving of the base station. The UE may interpret that according to method 4-1, among the CSI-related configurations configured through RRC, all configurations corresponding to periodic or semi-persistent CSI are deactivated when the base station operates in energy-saving mode. Alternatively, the UE may interpret that according to method 4-2, among the CSI-related configurations configured through RRC, all configurations corresponding to periodic CSI are deactivated when the base station operates in energy-saving mode. According to the above method 4-1 or method 4-2, the base station may indicate the CSI resources and reporting configuration to the UE to reduce the energy consumption of the base station, and the UE may report the CSI to the base station accordingly.

[0256] Fig.13 Another example of a method for configuring CSI resources according to an embodiment of the present disclosure is shown.

[0257] refer to Fig.13 , describes a method for configuring CSI resources performed according to the above method 4-1 or method 4-2. Fig.13 , shows an example in which some resources are configured as periodic resources and the corresponding resources are deactivated according to method 4-1 or method 4-2. Fig. 9 In the example, reference may be made to resourceType 8004 in CSI-ResourceConfig 8000 which indicates whether the transmission of CSI is aperiodic, semi-persistent or periodic.

[0258] Whether to apply method 4-1 or method 4-2 may be determined depending on whether the base station is configured in energy-saving mode. In the case where the base station is configured in energy-saving mode, the above method 4-1 or method 4-2 may be applied. The base station may explicitly indicate to the UE whether the base station is in energy-saving mode through configuration, or may indicate in an implicit manner. In the present disclosure, the method for the base station to indicate to the UE whether the base station is in energy-saving mode is not limited to a specific method.

[0259] According to the above method 4-1, among the CSI-related configurations configured through RRC, only the configuration corresponding to the aperiodic CSI is activated when the base station is in the energy-saving mode, and the method for configuring CSI-related resources and parameters in this case will be described. Figure 8B As described, in the case of non-periodic CSI, a CSI resource configuration may include multiple resource set configurations. In addition, a resource set may be selected through MAC-CE and / or DCI. Accordingly, the base station may configure multiple resource sets, and among them, some resource sets may configure CSI-related resources and parameters considering the case where the base station is in energy-saving mode, and other resource sets may configure CSI-related resources and parameters considering the case where the base station is not in energy-saving mode. In addition, in the case where the base station operates in energy-saving mode, the corresponding resource set may be selected and indicated through MAC-CE and / or DCI, and in the case where the base station does not operate in energy-saving mode, the corresponding resource set may be selected and indicated through MAC-CE and / or DCI.

[0260] According to the above method 4-2, among the CSI-related configurations configured through RRC, only the configuration corresponding to the aperiodic CSI and the semi-persistent CSI is activated when the base station is in the energy-saving mode, and a method for configuring CSI-related resources and parameters will be described. In the case of the configuration corresponding to the aperiodic CSI, the resource and parameter configuration according to the above method 4-1 may be possible. In contrast, in the case of the configuration corresponding to the semi-persistent CSI, only one resource set configuration may be included in one CSI resource configuration, such as Fig. 8A Accordingly, according to method 4-2, among the CSI-related configurations configured through RRC, when the base station is in energy-saving mode and also activates the configuration corresponding to the semi-persistent CSI, as Figure 8BThe method for allowing multiple resource set configurations for one CSI resource configuration can be applied to adjust the transmission parameters at short time intervals. Accordingly, according to method 4-2, when the base station is in energy-saving mode, multiple resource set configurations can be included in one CSI resource configuration for configurations corresponding to non-periodic CSI and semi-persistent CSI. In the case of configuring multiple resource sets, a resource set can be selected through MAC-CE and / or DCI. Accordingly, the base station can configure multiple resource sets, and among them, some resource sets can configure CSI-related resources and parameters considering the case where the base station is in energy-saving mode, and some other resource sets can configure CSI-related resources and parameters considering the case where the base station is not in energy-saving mode. In addition, when the base station operates in energy-saving mode, the corresponding resource set can be selected and indicated by MAC-CE and / or DCI, and when the base station does not operate in energy-saving mode, the corresponding resource set can be selected and indicated by MAC-CE and / or DCI.

[0261] The above method may be determined depending on whether the base station is configured in energy saving mode. Whether the base station is in energy saving mode may be explicitly indicated to the UE by configuration, or may be indicated in an implicit manner. In the present disclosure, the method for the base station to indicate to the UE whether the base station is in energy saving mode is not limited to a specific method.

[0262] <Method 5>

[0263] A method 5 for configuring CSI-related resources and parameters to reduce energy consumption of a base station according to an embodiment of the present disclosure will be described.

[0264] According to method 5, in order to adjust the CSI transmission parameters for aperiodic CSI, semi-persistent CSI and periodic CSI at short time intervals when the base station is in energy-saving mode, such as Figure 8B As shown, among the CSI-related configurations configured through RRC, multiple resource set configurations may be allowed for one CSI resource configuration. In the case of configuring multiple resource sets, one resource set may be selected through MAC-CE and / or DCI. Accordingly, the base station may configure multiple resource sets, and configure CSI-related resources and parameters for some resource sets considering the case where the base station is in energy-saving mode, and configure CSI-related resources and parameters for other resource sets considering the case where the base station is not in energy-saving mode. In addition, in the case where the base station operates in energy-saving mode, the corresponding resource set may be selected and indicated through MAC-CE and / or DCI, and in the case where the base station does not operate in energy-saving mode, the corresponding resource set may be selected and indicated through MAC-CE and / or DCI.

[0265] Method 5 may be determined based on whether the base station is configured in energy saving mode. Whether the base station is in energy saving mode may be explicitly indicated to the UE through configuration, or may be indicated in an implicit manner. In the present disclosure, the method for the base station to indicate to the UE whether the base station is in energy saving mode is not limited to a specific method.

[0266] According to the above method 5, the base station can indicate CSI resources and reporting configuration to the UE to reduce the energy consumption of the base station, and the UE can report CSI to the base station accordingly.

[0267] <Method 6>

[0268] The base station can indicate the number of CSI-RS ports and related parameters to the UE to reduce energy consumption.

[0269] When the base station turns off some power amplifiers (PAs) of the antenna as a base station energy saving method, the number of CSI-RS ports used for channel measurement needs to be adjusted accordingly and indicated to the UE. For example, consider a case where 32 power amplifiers of 32 antenna ports are turned on, 8 power amplifiers of only 8 antenna ports are turned on, and all remaining power amplifiers are turned off to save base station energy. In this case, if the number of CSI-RS ports for 32 antenna ports has been previously configured as 32, the number of CSI-RS ports needs to be adjusted to 8 or less, and then indicate that only the power amplifiers of 8 antenna ports are turned on.

[0270] In this way, when the base station performs an operation to reduce energy consumption, an operation may be required to adjust the number of CSI-RS ports configured through RRC and configuration of related parameters at short time intervals through MAC-CE and / or DCI.

[0271] refer to Fig. 9 , the number of CSI-RS ports and related parameters can be configured by referring to resourceMapping8122 in the NZP-CSI-RS-Resource 8120 configuration. Therefore, in order to adjust the corresponding configuration parameters, it is necessary to indicate the configuration of the number of CSI-RS ports 8122-2 and related parameters 8122-1, 8122-3, 8122-4, 8122-5 for each resource configuration included in the resource set configuration in all CSI resource configurations. In this case, not only must the nzp-CSI-RS-ResourceId 8121 be indicated, but a large amount of signaling overhead may also occur when considering the indication of the number of corresponding CSI-RS ports and related parameter configurations through MAC-CE and / or DCI.

[0272] As a method for reducing the signaling overhead, a method for indicating a differential value of the number of CSI-RS ports for each CSI resource configuration, each resource set configuration, or each resource configuration may be considered.

[0273] For example, you can use bits to indicate X differential values. For example, in the case of X=4, 2 bits are used, and in the case of information {-4, -2, 0, +2}, "-4" may indicate that the number of CSI-RS ports is reduced by 4 times, "-2" may indicate that the number of CSI-RS ports is reduced by 2 times, "0" may indicate that the number of CSI-RS ports has not changed, and "2" may indicate that the number of CSI-RS ports is increased by 2 times. In the present disclosure, the number of bits used to indicate the differential value and the method for interpreting the indicated bits are not limited thereto.

[0274] It is obvious that when the number of ports changes, the configuration of parameters (8122-1, 8122-3, 8122-4, 8122-5) also needs to be modified and indicated according to the number of ports. However, as a way to reduce signaling overhead, a method of assuming the configuration of parameters (8122-1, 8122-3, 8122-4, 8122-5) to be specific values ​​can be considered.

[0275] For example, frequencyDomainAllocation 8122-1 is a parameter indicating the frequency RE position within the RB in which the CSI-RS is transmitted. In the following Table 8, row 1 may indicate the frequency position as a 4-bit bitmap, row 2 may indicate the frequency position as a 12-bit bitmap, row 4 may indicate the frequency position as a 3-bit bitmap, and the remaining rows may indicate the frequency position as a 6-bit bitmap. Therefore, the following may be considered as a method for maintaining the value configured in the RRC without indicating the corresponding value in frequencyDomainAllocation 8122-1.

[0276] *CSI-RS ports may not be indicated to row 1 or row 4. This is a method for avoiding indication to rows using different bitmaps. In particular, since row 1 is a high-density pattern, it may not be necessary from the perspective of reducing base station energy consumption.

[0277] *In the case where a CSI-RS port is indicated to row 2 (port 1) among rows other than row 1 or row 4, the last 6 bits of the 12-bit bitmap of row 2 may be assumed to be 0 or 1.

[0278] Next, firstOFDMSymbolInTimeDomain 8122-3 is a parameter indicating a symbol position in an RB in which a CSI-RS is transmitted, and it can be assumed that a corresponding value configured by RRC does not change.

[0279] cdm-Type 8122-4 is a parameter indicating which code among {noCDM, fd-CDM2, cdm4-FD2-TD2, cdm8-FD2-TD4} is applied to CSI-RS, and may be assumed to be a specific cdm-Type unless the CSI-RS port is not indicated to row 2 (1 port, noCDM). For example, rows 3, 4, 5, 6, 7, 9, 11, 13, and 16 in the following Table 8 correspond to the case where fd-CDM2 is assumed.

[0280] Density 8122-5 is a parameter indicating the density of the CSI-RS using one of the values ​​{0.5, 1, 3}, and the corresponding value may also be fixed to one value. For example, the corresponding value may be fixed to 1.

[0281] [Table 8]

[0282]

[0283]

[0284] For example, when some power amplifiers (PAs) of the base station antennas are "turned off", the instruction for reducing the number of CSI-RS ports may not be performed if the number of antenna ports that are still "turned on" is less than the number of ports configured by RRC. In other words, the number of CSI-RS ports can be adjusted using the above method only if the number of antenna ports that are still "turned on" is greater than the number of ports configured by RRC.

[0285] <Method 7>

[0286] The base station can indicate to the UE the frequency domain in which the CSI-RS is sent in order to reduce energy consumption. The system bandwidth (BW) operating when the base station performs energy consumption reduction operations can also be changed. For example, when a portion of the power amplifier (PA) of the base station antenna is "turned off" as a base station energy saving method, the coverage may be reduced accordingly. In order to overcome this, a method for improving coverage by reducing the system BW can be considered. In the case where the base station changes the system BW in this way, the corresponding information can be indicated to the UE. In addition, the configuration of parameters related to the frequency domain in which the CSI-RS is sent can also be configured taking into account the changed system BW.

[0287] refer to Fig. 9, the configuration of parameters related to the frequency domain in which the CSI-RS is transmitted may refer to resourceMapping 8122 in the NZP-CSI-RS-Resource 8120 configuration. Specifically, freqBand8122-6 may correspond to the corresponding parameter, and "nrofRBs" and "startingRB" may be configured in RRC as parameters for determining the frequency domain in which the CSI-RS is transmitted. and When indicated to the UE, the frequency domain in which the CSI-RS is transmitted may be determined as shown in Table 9 below.

[0288] [Table 9]

[0289]

[0290] <Method 8>

[0291] The base station can indicate to the UE the period and offset value of sending CSI-RS to reduce energy consumption. The more frequently periodic CSI-RS transmission occurs, the more energy consumption of the base station will be caused. Therefore, in the mode of reducing energy consumption of the base station, when the CSI-RS transmission period configured by RRC is short, it is necessary to change the period to a large value. In addition, an operation to adjust the period to a short time interval may be necessary.

[0292] refer to Fig. 9 , the configuration of parameters related to the CSI-RS transmission period can refer to periodicityAndOffset (CSI-ResourcePeriodicityAndOffset) 8127 in the NZP-CSI-RS-Resource 8120 configuration. Therefore, in order to adjust the corresponding configuration parameters, it is necessary to indicate the configuration of the CSI-RS transmission period and offset value for each resource configuration included in the resource set configuration in all CSI resource configurations. In this case, not only must the nzp-CSI-RS-ResourceId 8121 be indicated, but also a large amount of signaling overhead may occur when the indication of the corresponding CSI-RS transmission period and offset value is considered through MAC-CE and / or DCI.

[0293] As a method for reducing such signaling overhead, a differential value of the CSI-RS transmission period may be indicated for each CSI resource configuration, each resource set configuration, or each resource configuration. bits to indicate X differential values. For example, in the case of X=4, 2 bits are used, and in the case of information {-4, -2, 0, +2}, "-4" may indicate that the CSI-RS transmission period is reduced by 4 times, "-2" may indicate that the CSI-RS transmission period is reduced by 2 times, "0" may indicate that the CSI-RS transmission period is unchanged, and "2" may indicate that the CSI-RS transmission period is increased by 2 times. In the present disclosure, the number of bits used to indicate the differential value and the method of interpreting the indicated bits are not limited thereto.

[0294] Table 10 shows an example of the period and corresponding offset configured by the periodicityAndOffset (CSI-ResourcePeriodicityAndOffset) 8127 parameter.

[0295] However, referring to Table 10 below, problems may arise when indicating the differential value of the CSI-RS transmission period. This is because the CSI-RS transmission period is 40 slots when reduced by 2 times from 80 slots, but there are also 64 slots in the middle of Table 10. Therefore, only specific periods in Table 10 below can be selected individually. For example, {slots20, slots40, slots80, slots160, slots320, slots640} can be assumed to be the CSI-RS transmission period used when the base station performs energy consumption reduction operations. In this case, in the case of indicating the differential value of the CSI-RS transmission period, the corresponding offset value can also be applied by changing the corresponding offset value from the value configured in the RRC to the differential value. For example, in the case where the CSI-RS transmission period configured in the RRC is 80 slots and the offset is 4, in the case where the CSI-RS transmission period is changed to 40 slots according to the differential value, the offset can be changed to 2.

[0296] [Table 10]

[0297]

[0298]

[0299] <Method 9>

[0300] Method 9 proposes a method for performing CSI measurement and reporting of a UE when the CSI resource configuration and CSI report configuration are adjusted at short time intervals during the operation process of the base station to reduce energy consumption. This may correspond to the case where the base station indicates a CSI measurement restriction (hereinafter referred to as MR (measurement restriction)). In other words, MR can be interpreted as an operation in which the base station constrains the UE to use a specific CSI-RS resource for CSI measurement for the changed transmission method, thereby enabling a more accurate CSI report to the base station.

[0301] In the case where the base station does not indicate MR activation, the UE can generally use the CSI-RS received before the CSI reference resource to perform channel measurement. How much CSI-RS the UE will use before the CSI reference resource can be determined by the UE implementation. For example, a measurement window can be used for this purpose. The method can also be applied to measure interference using CSI-RS.

[0302] In contrast, when the base station adjusts the MR at short time intervals through MAC-CE or DCI, the UE should measure the CSI based on the corresponding indication and report it to the base station. Therefore, in this case, it is necessary to define a CSI measurement method. Specifically, the following alternatives can be considered. The present disclosure is not limited to the following alternatives.

[0303] -Alternative 1: When the base station indicates MR through MAC-CE or DCI, the UE may perform channel measurement using only one of the latest CSI-RS resources received from the base station before the CSI reference resource. In addition, the UE may perform interference measurement using only one of the latest CSI-RS or CSI-IM resources received before the CSI reference resource. In addition, the UE may generate and report CSI based on this. According to Alternative 1, in the case where MR is indicated through MAC-CE or DCI, the UE may expect to provide at least one CSI-RS for channel measurement and interference measurement for CSI reporting. This may mean that the base station may indicate MR through MAC-CE or DCI so that at least one CSI-RS for channel and interference measurement may be sent to the UE after activating the MR indication and before the CSI reference resource. This may mean that the base station may adjust the timing of the MR indication so that there is at least one CSI-RS after activating the MR indication and before the CSI reference resource. The UE may not expect to receive the MR indication after the transmission timing of the latest / latest CSI-RS received before the CSI reference resource. This can be achieved through appropriate CSI-RS resource settings and CSI report settings configuration of the base station.

[0304] -Alternative 2: When the base station indicates the MR through MAC-CE or DCI, the base station may provide at least one CSI-RS for channel and interference measurement to the UE after the indication is activated and before the CSI reference resource.

[0305] The above alternatives may be used in combination. In addition, in the case of supporting one or more alternatives, a method of configuring the use of the alternatives through high-layer signaling may be considered. Here, the configuration through high-layer signaling may be an RRC configuration. In addition, although the above mentions the case of using MAC-CE or DCI as the MR indication method, a method of implicitly indicating the MR indication may also be considered. For example, it may be determined that the MR is indicated when the base station is in energy-saving mode. In other words, the MR indication may be determined depending on whether the base station is configured in energy-saving mode. Whether the base station is in energy-saving mode may be explicitly indicated to the UE through configuration, or may be indicated in an implicit manner. The method by which the base station indicates to the UE whether the base station is in energy-saving mode is not limited to the specific method in the present disclosure.

[0306] Fig.14 The signaling procedures of the UE and the base station according to an embodiment of the present disclosure are shown.

[0307] Fig.14 The operations in can be based on at least one of the above methods 1 to 9.

[0308] In operation 1410, the UE may receive an RRC message from the base station. That is, the base station may send an RRC message to the UE. The RRC message may include CSI-related parameters (e.g., CSI report configuration (CSI-ReportConfig 8400), CSI measurement configuration (CSI-MeasConfig 8500), CSI resource configuration (CSI-ResourceConfig 8000), and (multiple) sub-parameters). For example, the RRC message may include information indicating the number of ports.

[0309] In operation 1420, the UE may receive a message from the base station for deactivating at least one of the ports corresponding to the number of ports. That is, the base station may send a message to the UE to deactivate at least one port. The above message may be sent when the base station operates in an energy-saving mode. For example, the message may be sent via MAC-CE or DCI. The message may include resource allocation information in a frequency domain associated with at least one port. The message may also include resource allocation information in a time domain associated with at least one port. For example, the message may be composed of a bitmap.

[0310] In operation 1430, the UE may receive a CSI-RS from the base station based on the activated ports. That is, the base station may send the CSI-RS to the UE. The activated ports may be ports corresponding in number to the number of ports received through the RRC message but excluding at least one antenna port deactivated based on the message.

[0311] In operation 1440, the UE may report the CSI acquired based on the CSI-RS to the base station. That is, the base station may receive the CSI from the UE.

[0312] The above can be omitted Fig.14 Some operations in, or two or more operations may be combined and performed in one operation. In addition, Fig.14 The operations in can be done by Figures 15 to 17 It is executed by the UE device and base station device.

[0313] Fig.15 1 is a diagram showing a UE transceiver device in a wireless communication system according to an embodiment of the present disclosure. For convenience of explanation, devices that are not directly related to the present disclosure may be omitted from the drawings and descriptions.

[0314] refer to Fig.15 , the UE may be composed of a transmitter 1504, a receiver 1508, and a controller 1509, wherein the transmitter 1504 is composed of a UL transmission processing block 1501, a multiplexer 1502, and a transmission RF block 1503, and the receiver 1508 is composed of a DL reception processing block 1505, a demultiplexer 1506, and a reception RF block 1507. The controller 1509 may control the corresponding component blocks of the receiver 1508 to receive a data channel or a control channel transmitted by a base station, and control the corresponding component blocks of the transmitter 1504 to transmit a UL signal.

[0315] The UL transmission processing block 1501 of the transmitter 1504 of the UE may generate a signal for transmission by performing processes such as channel coding, modulation, etc. The signal generated in the UL transmission processing block 1501 may be multiplexed with another UL signal through the multiplexer 1502, undergo signal processing in the transmission RF block 1503, and then may be transmitted to the base station.

[0316] The receiver 1508 of the UE may demultiplex the signals received from the base station and distribute them to the corresponding DL reception processing blocks. The DL reception processing block 1505 may obtain control information or data sent by the base station by performing processes such as demodulation and channel decoding on the DL signals from the base station. The receiver 1508 of the UE may provide the output results of the DL reception processing block to the controller 1509 to support the operation of the controller 1509.

[0317] In order to perform the above-mentioned embodiments of the present disclosure, the transmitter, the receiver and the processor of the UE and the base station are respectively Fig.16 and Fig.17 Shown in.

[0318] Specifically, Fig.16 is a block diagram showing an internal structure of a UE according to an embodiment of the present disclosure.

[0319] refer to Fig.16 , the UE of the present disclosure may include a UE receiver 1600, a UE transmitter 1604, and a UE processor 1602. In an embodiment of the present disclosure, the UE receiver 1600 and the UE transmitter 1604 may be collectively referred to as a transceiver. The transceiver may send a signal to a base station or receive a signal from a base station. The signal may include control information and data. To this end, the transceiver may be composed of an RF transmitter for up-converting the frequency of a signal to be sent and amplifying the signal, an RF receiver for low-noise amplifying a received signal and down-converting the frequency of the received signal, and the like. In addition, the transceiver may receive a signal on a wireless channel and output the signal to the UE processor 1602, and send a signal output from the UE processor 1602 on a wireless channel. The UE processor 1602 may control a series of processes of the UE to operate according to the above-mentioned embodiments of the present disclosure.

[0320] Fig.17 is a block diagram showing an internal structure of a base station according to an embodiment of the present disclosure.

[0321] refer to Fig.17 , the base station of the present disclosure may include a base station receiver 1701, a base station transmitter 1705 and a base station processor 1703. In an embodiment of the present disclosure, the base station receiver 1701 and the base station transmitter 1705 may be collectively referred to as a transceiver. The transceiver may send a signal to a UE or receive a signal from a UE. The signal may include control information and data. To this end, the transceiver may be composed of an RF transmitter for up-converting the frequency of a signal to be sent and amplifying the signal, an RF receiver for low-noise amplifying a received signal and down-converting the frequency of the received signal, and the like. In addition, the transceiver may receive a signal on a wireless channel and output the signal to the base station processor 1703, and send a signal output from the base station processor 1703 on a wireless channel. The base station processor 1703 may control a series of processes of the base station to operate according to the above-mentioned embodiments of the present disclosure.

[0322] At the same time, the embodiments of the present disclosure disclosed in this specification and the accompanying drawings are only specific examples presented to easily explain the technical content of the present disclosure and to help understand the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art that other modified examples based on the technical ideas of the present disclosure are possible. In addition, each of the above-mentioned embodiments can be combined and operated as needed. For example, the parts of all embodiments of the present disclosure can be combined and operated as a base station and a UE.

Claims

1. A method performed by a terminal in a wireless communication system, comprising: receiving a radio resource control (RRC) message including information indicating a number of ports from a base station; receiving, from the base station, a message for deactivating at least one port among the ports corresponding to the number of ports, wherein the message includes resource allocation information in a frequency domain associated with the at least one port; receiving a channel state information reference signal (CSI-RS) from the base station via ports among the ports corresponding to the number of ports but excluding at least one antenna port deactivated based on the message; and and reporting channel state information (CSI) acquired based on the CSI-RS to the base station.

2. The method according to claim 1, wherein: The message further includes resource allocation information in the time domain associated with the at least one port.

3. The method according to claim 1, wherein: The message is received via a Medium Access Control Control Element (MAC-CE) or a Downlink Control Channel (DCI).

4. The method according to claim 1, wherein: The message consists of a bitmap.

5. A method performed by a base station in a wireless communication system, comprising: sending a radio resource control (RRC) message including information indicating the number of ports to the terminal; determining to deactivate at least one port among the ports corresponding to the number of the ports; Sending a message for deactivating the at least one port to the terminal, wherein the message includes resource allocation information in the frequency domain associated with the at least one port; transmitting a channel state information reference signal (CSI-RS) to the terminal via ports among the ports corresponding to the number of ports but excluding at least one antenna port deactivated based on the message; and Channel state information (CSI) based on the CSI-RS is received from the terminal.

6. The method according to claim 5, wherein: The message further includes resource allocation information in the time domain associated with the at least one port.

7. The method according to claim 5, wherein: The message is sent via a Medium Access Control Element (MAC-CE) or a Downlink Control Channel (DCI).

8. The method according to claim 5, wherein: The message consists of a bitmap.

9. A terminal in a wireless communication system, comprising: Transceiver; as well as a controller, functionally connected to the transceiver, Wherein, the controller is configured as: receiving a radio resource control (RRC) message including information indicating a number of ports from a base station; receiving, from the base station, a message for deactivating at least one port among the ports corresponding to the number of ports, wherein the message includes resource allocation information in a frequency domain associated with the at least one port; receiving a channel state information reference signal (CSI-RS) from the base station via ports among the ports corresponding to the number of ports but excluding at least one antenna port deactivated based on the message; and and reporting channel state information (CSI) acquired based on the CSI-RS to the base station.

10. The terminal according to claim 9, wherein: The message further includes resource allocation information in the time domain associated with the at least one port.

11. The terminal according to claim 9, wherein: The message is received via a Medium Access Control Control Element (MAC-CE) or a Downlink Control Channel (DCI).

12. The terminal according to claim 9, wherein: The message consists of a bitmap.

13. A base station in a wireless communication system, comprising: Transceiver; as well as a controller, functionally connected to the transceiver, Wherein, the controller is configured as: sending a radio resource control (RRC) message including information indicating the number of ports to the terminal; determining to deactivate at least one port among the ports corresponding to the number of the ports; Sending a message for deactivating the at least one port to the terminal, wherein the message includes resource allocation information in the frequency domain associated with the at least one port; transmitting a channel state information reference signal (CSI-RS) to the terminal via ports among the ports corresponding to the number of ports but excluding at least one antenna port deactivated based on the message; and Channel state information (CSI) based on the CSI-RS is received from the terminal.

14. The base station according to claim 13, wherein: The message further includes resource allocation information in the time domain associated with the at least one port.

15. The base station according to claim 13, wherein: The message is sent via a medium access control element (MAC-CE) or a downlink control channel (DCI), and The message consists of a bitmap.

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