Method and apparatus for power reduction in wireless communication systems - Patents.com

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The present disclosure discloses a method for a 5G or 6G communication system, comprising: receiving a signal including UE capability information from a terminal; identifying a base station mode based on the UE capability information; transmitting a base station mode change signal to the terminal based on the base station mode; receiving a response signal from the terminal; and changing a magnitude of transmission power based on the base station mode and transmitting a signal to the terminal, the terminal capability information including at least one of support information regarding an energy saving mode for the base station, control information related to a frequency band supported by the terminal, and power information related to a channel bandwidth supported by the terminal, the base station mode being one of a power saving mode for the base station or a general mode for the base station, and the magnitude of the transmission power being smaller in the general mode than in the power saving mode.

Description

[Technical field]

[0001] The present disclosure relates to a communication method for a wireless communication system, and more particularly to a method and apparatus for energy saving in a wireless communication system. [Background technology]

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz band, such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band, known as mmWave, such as 28GHz and 39GHz, known as above 6GHz. In addition, in the case of 6G mobile communication technology, known as the Beyond 5G system, implementation in the terahertz band (for example, 95GHz to 3THz band) is being considered to achieve transmission speeds 50 times faster than 5G mobile communication technology and ultra-low latency times that are reduced to one-tenth of those of 5G mobile communication technology.

[0003] In the early stage of 5G mobile communication technology, the goal is to meet the service support and performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and Massive Machine-Type Communications (mMTC). The following technologies have been proposed: Beamforming and Massive MIMO to mitigate the path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves; various numerology support (such as operation of multiple subcarrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources; initial access technology to support multiple beam transmission and wideband; definition and operation of Band-Width Part (BWP); new channel coding methods such as Low Density Parity Check (LDPC) code for large-volume data transmission and Polar Code for reliable transmission of control information; L2 pre-processing (L2 Standardization has progressed in areas such as network pre-processing, and network slicing, which provides dedicated networks specialized for specific services.

[0004] Currently, discussions are underway to improve and enhance the initial 5G mobile communications technology in consideration of the services that 5G mobile communications technology was intended to support. Physical layer standardization is underway for technologies such as Vehicle-to-Everything (V2X), which assists autonomous vehicles in making driving decisions based on their own position and status information transmitted by the vehicle to increase user convenience, New Radio Unlicensed (NR-U), which aims to operate systems in unlicensed spectrum in accordance with various regulatory requirements, technology to reduce power consumption of NR terminals (UE Power Saving), Non-Terrestrial Network (NTN), which is direct communication between terminals and satellites to ensure coverage in areas where communication with terrestrial networks is not possible, and positioning.

[0005] In addition, standardization is underway in the areas of radio interface architecture / protocol for technologies such as the Industrial Internet of Things (IIoT) to support new services through collaboration and convergence with other industries, Integrated Access and Backhaul (IAB) to provide nodes for expanding network service areas by integrating wireless backhaul links and access links, mobility enhancement technologies including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) to simplify random access procedures. Standardization is also underway in the areas of system architecture / service for 5G baseline architecture (e.g., Service based Architecture, Service based Interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) to provide services based on the location of the terminal.

[0006] When such 5G mobile communication systems are commercialized, it is expected that the number of connected devices, which is on an explosive increase, will be connected to the communication network, which will require the enhancement of the functions and performance of the 5G mobile communication system and the integrated operation of connected devices.To this end, new research will be conducted on eXtended Reality (XR) to efficiently support Augmented Reality (AR), Virtual Reality (VR), Mixed Reality (MR), etc., 5G performance improvement and complexity reduction using Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, drone communication, etc.

[0007] In addition, the development of such 5G mobile communication systems will be the basis for the development of multiple antenna transmission technologies such as new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, full dimensional MIMO (FD-MIMO), array antennas, and large scale antennas, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, AI-based communication technology that utilizes satellites and artificial intelligence (AI) from the design stage and internalizes end-to-end AI support functions to realize system optimization, and next-generation distributed computing technology that utilizes ultra-high performance communication and computing resources to realize services of a complexity that exceeds the limits of terminal computing capabilities.

[0008] With the development of mobile communication systems as described above, it becomes possible to provide various services, and there is a demand for methods for providing such services effectively, and in particular, there is a demand for methods and apparatus for energy saving in wireless communication systems. Summary of the Invention [Problem to be solved by the invention]

[0009] The disclosed embodiments aim to provide an apparatus and method capable of effectively providing services in a mobile communication system. [Means for solving the problem]

[0010] According to the present disclosure, there is disclosed a method performed by a base station in a wireless communication system, the method including the steps of receiving a signal including terminal capability information from a terminal; identifying a base station mode based on the terminal capability information; transmitting a base station mode change signal to the terminal based on the base station mode; receiving a response signal from the terminal; and changing a magnitude of transmission power based on the base station mode and transmitting a signal to the terminal, wherein the terminal capability information includes at least one of support information regarding an energy saving mode for the base station, control information related to a frequency band supported by the terminal, and power information related to a channel bandwidth supported by the terminal, the base station mode being one of a power saving mode for the base station or a general mode for the base station, and the magnitude of the transmission power being smaller in the general mode than in the power saving mode. Effect of the Invention

[0011] The disclosed embodiments provide an apparatus and method for effectively providing services in a mobile communication system. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 illustrates the basic structure of a time-frequency resource region in a 5G system according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 illustrates a time domain mapping structure and beam sweeping operation of a synchronization signal according to an embodiment of the present disclosure. [Diagram 3] FIG. 1 illustrates a random access procedure according to one embodiment of the present disclosure. [Figure 4] A diagram showing a procedure in which a terminal reports terminal capability (UE capability) information to a base station according to one embodiment of the present disclosure. [Diagram 5] FIG. 2 illustrates the interrelationship of frequency bands, coverage, and bandwidth according to one embodiment of the present disclosure. [Figure 6] FIG. 2 illustrates a base station deployment scenario according to one embodiment of the present disclosure. [Figure 7] FIG. 2 illustrates a base station deployment scenario according to one embodiment of the present disclosure. [Figure 8] FIG. 2 illustrates the interrelationship of downlink signal transmission power settings according to one embodiment of the present disclosure. [Figure 9] FIG. 1 illustrates a transmit power adjustment per CSI-RS resource according to one embodiment of the present disclosure. [Figure 10] A diagram showing a measurement reporting procedure of a terminal according to one embodiment of the present disclosure. [Figure 11] A diagram showing a terminal procedure for changing downlink signal transmission power according to one embodiment of the present disclosure. [Figure 12] 11 is a flowchart illustrating a terminal procedure according to one embodiment of the present disclosure. [Figure 13] 1 is a flowchart illustrating a base station procedure according to one embodiment of the present disclosure. [Figure 14] FIG. 2 illustrates a terminal transceiver device according to an embodiment of the present disclosure. [Figure 15] FIG. 2 is a block diagram showing the structure of a terminal according to an embodiment of the present disclosure. [Figure 16] FIG. 2 is a block diagram showing the structure of a base station according to one embodiment of the present disclosure; [Figure 17] 1 is a flowchart illustrating a base station procedure according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, when describing the present disclosure, if it is determined that a specific description of related known functions or configurations may unnecessarily obscure the gist of the present disclosure, the detailed description will be omitted. The terms described below are defined in consideration of the functions in the present disclosure, and may vary depending on the intention or practice of a user or operator. Therefore, the definitions should be based on the contents of this specification as a whole.

[0014] The advantages and features of the present disclosure, and the methods for achieving them, will become clear by referring to the embodiments described in detail below with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but can be implemented in various different forms, and the present embodiments are provided merely to complete the present disclosure and to fully inform those skilled in the art to which the present disclosure pertains, and the present disclosure is defined only by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

[0015] In this case, it will be understood that each block of the process flow diagram and combination of the flow diagrams can be implemented by computer program instructions. These computer program instructions can be loaded into a processor of a general purpose computer, a special purpose computer, or other programmable data processing equipment, such that the instructions executed by the processor of the computer or other programmable data processing equipment create means for performing the functions described in the flow chart block(s). These computer program instructions can also be stored in a computer usable or computer readable memory that can direct the computer or other programmable data processing equipment to implement the functions in a particular manner, such that the instructions stored in the computer usable or computer readable memory can produce an article of manufacture that includes instruction means for performing the functions described in the flow chart block(s). Computer program instructions may be embodied on a computer or other programmable data processing device such that a sequence of operations is performed on the computer or other programmable data processing device to generate a computer-implemented process, the instructions for operating the computer or other programmable data processing device may provide steps for performing the functions described in the flow diagram block(s).

[0016] Also, each block may represent a module, segment, or portion of code that includes one or more executable instructions for performing a particular logical function(s). It should also be noted that in some alternative embodiments, the functions noted in the blocks may occur out of order. For example, two blocks shown in succession may in fact be performed substantially simultaneously, or the blocks may sometimes be performed in reverse order depending on the relevant functions.

[0017] In this case, the term "unit" used in the present embodiment means software or hardware components such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and the "unit" plays any role. However, the "unit" is not limited to software or hardware. The "unit" may be configured to be in an addressable storage medium or to execute one or more processors. Thus, as an example, the "unit" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The components and functions provided in the "unit" may be combined into fewer components and "units" or further separated into additional components and "units". Moreover, the components and "units" may be implemented to execute one or more CPUs in a device or a security multimedia card. In addition, in the embodiment, the "unit" may include one or more processors.

[0018] In the following description of the present disclosure, if it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the gist of the present disclosure, the detailed description will be omitted. Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings.

[0019] In the following description, terms for identifying connection nodes, terms for network entities, terms for messages, terms for interfaces between network entities, terms for various identification information, etc. are provided as examples for the convenience of description. Therefore, the present disclosure is not limited to the terms described below, and other terms for objects having equivalent technical meanings may be used.

[0020] In the following description, the terms physical channel and signal may be used interchangeably with data or control signals. For example, PDSCH (physical downlink shared channel) is a term that refers to a physical channel through which data is transmitted, but PDSCH may also be used to refer to data. That is, in this disclosure, the expression "transmitting a physical channel" may be interpreted as being equivalent to the expression "transmitting data or signals via a physical channel."

[0021] Hereinafter, in this disclosure, upper signaling refers to a signaling method transmitted from a base station to a terminal using a downlink data channel of a physical layer, or from a terminal to a base station using an uplink data channel of a physical layer. Upper signaling can be understood as radio resource control (RRC) signaling or media access control (MAC) control element (CE).

[0022] Hereinafter, for convenience of explanation, the present disclosure uses terms and names defined in the 3GPP (registered trademark) NR (New Radio: 5th generation mobile communication standard) standard. However, the present disclosure is not limited to the above terms and names, and may be similarly applied to systems based on other standards. In addition, the term terminal may refer to not only mobile phones, smartphones, IoT devices, and sensors, but also other wireless communication devices.

[0023] Hereinafter, a base station is an entity that allocates resources to a terminal, and may be at least one of a gNodeB, a gNB, an eNodeB, an eNB, a NodeB, a BS (Base Station), a radio access unit, a base station controller, or a node on a network. A terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system that can perform communication functions. Of course, it is not limited to the examples described.

[0024] In recent years, in order to handle the explosive increase in mobile data traffic, 5G (5G), the next-generation communication system after LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)) and LTE-A (LTE-Advanced or E-UTRA Evolution), has been developed. th The initial standard for the 5G Generation system or New Radio access technology (NR) has been completed. In contrast to conventional mobile communication systems that focus on normal voice / data communication, the 5G system aims to meet various services and requirements, such as eMBB (enhanced Mobile BroadBand) service for improving conventional voice / data communication, Ultra-Reliable and Low Latency Communication (URLLC) service, and massive MTC (Machine Type Communication) service for supporting large-volume machine-to-machine communication.

[0025] While the system transmission bandwidth per single carrier of conventional LTE and LTE-A is limited to a maximum of 20 MHz, the 5G system aims to provide ultra-high-speed data services reaching several Gbps by utilizing ultra-wide bandwidth, which is much wider than that. Therefore, the 5G system is considering ultra-high frequency bands from several GHz to up to 100 GHz as candidate frequencies, where it is relatively easy to secure ultra-wide bandwidth frequencies. In addition, it is possible to secure wide bandwidth frequencies for the 5G system by frequency reallocation or allocation within frequency bands ranging from several hundred MHz to several GHz used in conventional mobile communication systems.

[0026] Ultra-high frequency radio waves have wavelengths of a few millimeters and are also called millimeter waves (mmWave). However, in the ultra-high frequency band, the path loss of radio waves increases in proportion to the frequency band, and the coverage of mobile communication systems becomes smaller.

[0027] In order to overcome the drawback of reduced coverage in the ultra-high frequency band, a beamforming technique is applied that uses multiple antennas to concentrate the radiation energy of radio waves to a specific destination to increase the reach of radio waves. That is, the beam width of a signal to which the beamforming technique is applied is relatively narrow, and the radiation energy is concentrated within the narrow beam width to increase the reach of radio waves. The beamforming technique can be applied to both the transmitting end and the receiving end. In addition to the effect of increasing coverage, the beamforming technique has the effect of reducing interference in areas other than the beamforming direction. In order for the beamforming technique to operate properly, an accurate measurement and feedback method of the transmitting / receiving beam is required. The beamforming technique can be applied to a control channel or data channel that corresponds one-to-one between a specific terminal and a base station. In addition, the beamforming technique can be applied to a control channel and a data channel for transmitting common signals that the base station transmits to multiple terminals in the system, such as a synchronization signal, a physical broadcast channel (PBCH), and system information, in order to increase coverage. When applying beamforming technology to a common signal, a beam sweeping technology that changes the beam direction and transmits a signal is additionally applied so that the common signal can reach a terminal located anywhere within the cell.

[0028] Another requirement of the 5G system is ultra-low latency service with a transmission delay between transmitting and receiving ends of about 1 ms. One way to reduce the transmission delay is to design a frame structure based on a short TTI (Transmission Time Interval) compared to LTE and LTE-A. TTI is the basic time unit for scheduling, and the TTI of the conventional LTE and LTE-A systems is 1 ms, which corresponds to the length of one subframe. For example, the 5G system can have a short TTI of 0.5 ms, 0.25 ms, 0.125 ms, etc., which is shorter than that of the conventional LTE and LTE-A systems, based on the short TTI to meet the requirement for ultra-low latency service.

[0029] 1 is a diagram illustrating a basic structure of a time-frequency resource region of a 5G system according to an embodiment of the present disclosure, that is, FIG. 1 is a diagram illustrating a basic structure of a time-frequency resource region, which is a radio resource region in which data or control channels of a 5G system are transmitted.

[0030] Referring to FIG. 1, the horizontal axis represents the time domain and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain of the 5G system is an OFDM (Orthogonal Frequency Division Multiplexing) symbol,

number

number

[0031] The basic unit of a resource in the time-frequency domain is a resource element (RE) 112, which can be expressed by an OFDM symbol index and a subcarrier index. A resource block (RB or Physical Resource Block, PRB) in the frequency domain is

number

number

[0032] In a 5G system, a base station maps data in units of RBs and generally performs scheduling for a given terminal on RBs constituting one slot. That is, in a 5G system, the basic time unit for which scheduling is performed is a slot, and the basic frequency unit for which scheduling is performed may be an RB.

[0033] Number of OFDM symbols

number

number

number

[0034] In 5G systems, various frame structures can be supported by adjusting the subcarrier spacing to meet different services and requirements. For example, In terms of the operating frequency band, the larger the subcarrier spacing, the more advantageous it is for restoring phase noise in the high frequency band. From the perspective of transmission time, a larger subcarrier spacing shortens the symbol length in the time domain, which results in a shorter slot length, which is advantageous for supporting ultra-low latency services such as URLLC. In terms of cell size, the longer the CP length, the larger the cell that can be supported, so the smaller the subcarrier spacing, the larger the cell that can be supported. A cell is a concept that refers to the area covered by one base station in mobile communications.

[0035] Subcarrier spacing, CP length, etc. are essential information for OFDM transmission and reception, and smooth transmission and reception is possible when the base station and terminal recognize the subcarrier spacing, CP length, etc. as common values. [Table 1] shows the subcarrier spacing configuration (μ) and subcarrier spacing (Δ f ), which represents the relationship between CP length.

[0036] [Table 1]

[0037] [Table 2] shows the number of symbols per slot for each subcarrier spacing setting (μ) in the case of normal CP.

number

number

number

[0038] [Table 2]

[0039] [Table 3] shows the number of symbols per slot for each subcarrier spacing setting (μ) in the case of extended CP.

number

number

number

[0040] [Table 3]

[0041] In the early stages of the introduction of the 5G system, it is expected to coexist or operate in dual mode with at least the conventional LTE and / or LTE-A (hereinafter referred to as LTE / LTE-A) systems. This allows the conventional LTE / LTE-A to provide stable system operation to terminals, while the 5G system can provide improved services to terminals. Therefore, the frame structure of the 5G system must include at least the frame structure or essential parameter set of LTE / LTE-A (subcarrier spacing = 15 kHz). For example, comparing a frame structure with subcarrier spacing setting μ=0 (hereinafter referred to as frame structure A) with a frame structure with subcarrier spacing setting μ=1 (hereinafter referred to as frame structure B), frame structure B shows that the subcarrier spacing and RB size are twice as large, and the slot length and symbol length are twice as small, compared to frame structure A. In the case of frame structure B, two slots make up one subframe, and 20 subframes can make up one frame.

[0042] Generalizing the frame structure of the 5G system provides high scalability by making the essential parameter sets, such as subcarrier spacing, CP length, and slot length, have integer multiple relationships for each frame structure. A subframe with a fixed length of 1 ms can be defined to represent a reference time unit that is independent of the frame structure.

[0043] The frame structure of the 5G system can be applied to various scenarios. In terms of cell size, the longer the CP length, the larger the cell that can be supported, so frame structure A can support a relatively larger cell compared to frame structure B. In terms of operating frequency band, the larger the subcarrier spacing is, the more advantageous it is for restoring phase noise in the high frequency band, so frame structure B can support a relatively higher operating frequency compared to frame structure A. In terms of services, the shorter the slot length, which is the basic time unit for scheduling, the more advantageous it is for supporting ultra-low latency services such as URLLC, so frame structure B can be more suitable for URLLC services compared to frame structure A.

[0044] In the following description of the present disclosure, uplink (UL) may refer to a wireless link through which a terminal transmits data or control signals to a base station, and downlink (DL) may refer to a wireless link through which a base station transmits data or control signals to a terminal.

[0045] In the initial access stage when a terminal first connects to a system, the terminal can obtain a cell ID by performing downlink time and frequency synchronization from a synchronization signal transmitted by a base station through a cell search. The terminal can then receive a Physical Broadcast Channel (PBCH) using the obtained cell ID and obtain a Master Information Block (MIB), which is essential system information, from the PBCH. In addition, the terminal can obtain cell-common transmission and reception related control information by receiving system information (System Information Block, SIB) transmitted by the base station. The cell-common transmission and reception related control information can include random access related control information, paging related control information, and common control information related to various physical channels.

[0046] A synchronization signal is a reference signal for cell search, and subcarrier spacing may be applied for each frequency band to suit the channel environment, such as phase noise, etc. In the case of a data channel or a control channel, different subcarrier spacing may be applied depending on the service type in order to support various services as described above.

[0047] FIG. 2 is a diagram illustrating a time domain mapping structure and beam sweeping operation of a synchronization signal according to one embodiment of the present disclosure.

[0048] For purposes of explanation, the following components can be defined: -PSS (Primary Synchronization Signal): A signal that serves as a reference for DL ​​time / frequency synchronization, providing part of the cell ID information. -SSS (Secondary Synchronization Signal): Provides a reference for DL ​​time / frequency synchronization and provides the remaining part of the cell ID information. Additionally, it can serve as a reference signal for demodulation of PBCH. - PBCH (Physical Broadcast Channel): Provides MIB (Master Information Block), which is essential system information required for transmission and reception of data channels and control channels of a terminal. MIB (Master Information Block) can include information such as search space related control information indicating radio resource mapping information of a control channel, scheduling control information for a separate data channel that transmits system information, and SFN (System Frame Number), which is a frame unit index serving as a timing reference. -SS / PBCH block (Synchronization Signal / PBCH Block or SSB): An SS / PBCH block consists of N OFDM symbols and is a combination of PSS, SSS, PBCH, etc. In a system to which beam sweeping technology is applied, an SS / PBCH block is the smallest unit to which beam sweeping is applied. In a 5G system, N may be 4. A base station can transmit up to L SS / PBCH blocks, and the L SS / PBCH blocks are mapped within a half frame (0.5 ms). The L SS / PBCH blocks are repeated periodically in a predetermined period P unit. The base station can notify the terminal of the period P through signaling. If there is no separate signaling for the period P, the terminal applies a pre-determined default value. Each SS / PBCH block has an SS / PBCH block index ranging from 0 to a maximum of L-1, and the terminal can know the SS / PBCH block index through SS / PBCH detection.

[0049] Referring to FIG. 2, beam sweeping is applied in units of SS / PBCH blocks according to the flow of time. In the example of FIG. 2, the first terminal 205 receives the SS / PBCH block using a beam radiated in the #d0 (203 in FIG. 2) direction by beamforming applied to the SS / PBCH block #0 at time t1 201. The second terminal 206 receives the SS / PBCH block using a beam radiated in the #d4 (204 in FIG. 2) direction by beamforming applied to the SS / PBCH block #4 at time t2 202. The terminal can obtain an optimal synchronization signal through a beam radiated from the base station in the direction in which the terminal is located. For example, the first terminal 205 may have difficulty obtaining time / frequency synchronization and necessary system information from the SS / PBCH block through a beam radiated in the #d4 direction, which is far from the location of the first terminal.

[0050] In addition to the initial access procedure, the terminal can receive the SS / PBCH block to determine whether the radio link quality of the current cell is maintained above a certain level. Also, in a handover procedure in which the terminal moves the connection from the current cell to a neighboring cell, the terminal can receive the SS / PBCH block of the neighboring cell to determine the radio link quality of the neighboring cell and to obtain time / frequency synchronization of the neighboring cell.

[0051] After the terminal acquires MIB and system information from the base station through an initial access procedure, the terminal can perform a random access procedure to switch the link with the base station to a connected state (connected state or RRC_CONNECTED state). Upon completion of the random access procedure, the terminal is switched to a connected state, and one-to-one communication between the base station and the terminal is possible. Hereinafter, the random access procedure will be described in detail with reference to FIG. 3.

[0052] FIG. 3 is a diagram illustrating a random access procedure according to one embodiment of the present disclosure.

[0053] Referring to FIG. 3, in a first step 310 of the random access procedure, the terminal transmits a random access preamble to the base station. In the random access procedure, the random access preamble, which is the first transmission message of the terminal, may be referred to as message 1. The base station may measure a transmission delay value between the terminal and the base station from the random access preamble and perform uplink synchronization. In this case, the terminal may arbitrarily select which random access preamble to use from a random access preamble set previously given by system information. In addition, the initial transmission power of the random access preamble may be determined according to a path loss between the base station and the terminal measured by the terminal. In addition, the terminal may determine a transmission beam direction of the random access preamble from a synchronization signal received from the base station and transmit the random access preamble.

[0054] In a second step 320, the base station transmits an uplink transmission timing adjustment command to the terminal based on the transmission delay value measured from the random access preamble received in the first step 310. The base station may also transmit an uplink resource and power control command to be used by the terminal as scheduling information. The scheduling information may include control information for the uplink transmission beam of the terminal.

[0055] If the terminal fails to receive a Random Access Response (RAR) (or message 2), which is scheduling information for message 3, from the base station within a predetermined time in the second step 320, it can perform the first step 310 again. If the terminal performs the first step 310 again, the terminal can increase the transmission power of the random access preamble by a predetermined step and transmit it (power ramping) to increase the probability of receiving the random access preamble from the base station.

[0056] In a third step 330, the terminal transmits uplink data (message 3) including its terminal ID to the base station via an uplink data channel (Physical Uplink Shared Channel, PUSCH) using the uplink resources allocated in the second step 320. The transmission timing of the uplink data channel for transmitting Message 3 may follow the timing control command received from the base station in the second step 320. And, the transmission power of the uplink data channel for transmitting Message 3 may be determined taking into consideration the power control command received from the base station in the second step 320 and the power ramping value of the random access preamble. The uplink data channel for transmitting Message 3 may refer to the first uplink data signal that the terminal transmits to the base station after the terminal transmits the random access preamble.

[0057] In a fourth step 340, if the base station determines that the terminal has performed random access without collision with other terminals, it transmits data (message 4) including the ID of the terminal that transmitted the uplink data in the third step 330 to the corresponding terminal. When the terminal receives the signal transmitted by the base station in the fourth step 340 from the base station, it can determine that the random access is successful. Then, the terminal can transmit HARQ-ACK information indicating whether or not it has successfully received message 4 to the base station via an uplink control channel (Physical Uplink Control Channel, PUCCH).

[0058] If the data transmitted by the terminal in the third step 330 collides with data from another terminal, causing the base station to fail to receive the data signal from the terminal, the base station may not transmit any more data to the terminal. Therefore, if the terminal fails to receive the data transmitted from the base station in the fourth step 340 within a predetermined time, it may determine that the random access procedure has failed and may restart from the first step 310.

[0059] If the random access procedure is successfully completed, the terminal is switched to a connected state, and one-to-one communication between the base station and the terminal is possible. The base station receives UE capability information from the terminal in the connected state and can adjust scheduling by referring to the UE capability information of the terminal. The terminal can inform the base station through the UE capability information whether the terminal itself supports a certain function, the maximum allowable value of the function supported by the terminal, etc. Therefore, the UE capability information reported by each terminal to the base station can be a different value for each terminal.

[0060] As an example, the terminal can report UE capability information including at least a part of the following control information to the base station as UE capability information. -Frequency band-related control information supported by the terminal -Channel bandwidth-related control information supported by the terminal - Maximum modulation scheme related control information supported by the terminal -Control information related to the maximum number of beams supported by the terminal -Control information related to the maximum number of layers supported by the terminal -CSI report related control information supported by the terminal Control information regarding whether the terminal supports frequency hopping -Bandwidth-related control information if carrier aggregation (CA) is supported -If carrier aggregation is supported, control information regarding whether cross carrier scheduling is supported

[0061] FIG. 4 is a diagram illustrating a procedure in which a terminal reports terminal capability information (UE capability) to a base station according to one embodiment of the present disclosure.

[0062] 4, in step 410, the base station 402 may transmit a UE capability information request message to the terminal 401. In response to the UE capability information request of the base station, in step 420, the terminal transmits UE capability information to the base station.

[0063] Hereinafter, a scheduling method in which a base station transmits downlink data to a terminal or instructs the terminal to transmit uplink data will be described.

[0064] Downlink control information (DCI) is control information that a base station transmits to a terminal via a downlink, and may include downlink data scheduling information or uplink data scheduling information for a certain terminal. In general, a base station can transmit DCI to each terminal via a physical downlink control channel (PDCCH) after independently channel coding the DCI for each terminal.

[0065] The base station can apply a predetermined DCI format to the terminal to be scheduled depending on the purpose, such as whether the information is scheduling information for downlink data (downlink assignment), whether the information is scheduling information for uplink data (uplink grant), or whether the information is DCI for power control.

[0066] The base station can transmit downlink data to the terminal via a Physical Downlink Shared Channel (PDSCH), which is a physical channel for transmitting downlink data. Scheduling information such as a specific mapping position in the time and frequency domain of the PDSCH, a modulation scheme, HARQ-related control information, and power control information can be notified to the terminal by the base station via DCI associated with downlink data scheduling information among DCI transmitted via the PDCCH.

[0067] The UE can transmit uplink data to the base station via a PUSCH (Physical Uplink Shared Channel), which is a physical channel for transmitting uplink data. Scheduling information such as a specific mapping position in the time and frequency domain of the PUSCH, a modulation scheme, HARQ-related control information, and power control information can be notified to the UE by the base station via DCI associated with uplink data scheduling information among DCI transmitted via the PDCCH.

[0068] The time-frequency resource to which the PDCCH is mapped is called a control resource set (CORESET). The CORESET may be set to the entire or part of the frequency resources of the bandwidth supported by the terminal in the frequency domain. In the time domain, it may be set to one or more OFDM symbols, which may be defined as the CORESET duration (Control Resource Set Duration). The base station may set one or more CORESETs to the terminal through higher layer signaling (e.g., system information, Master Information Block (MIB), Radio Resource Control (RRC) signaling). Setting a CORESET to the terminal may mean providing information such as a CORESET identifier, a frequency location of the CORESET, and a symbol length of the CORESET. The information provided by the base station to the terminal to set the CORESET may include at least a portion of the information included in Table 4.

[0069] [Table 4-1] [Table 4-2]

[0070] CORESET is the frequency domain

number

number

[0071] As a transmission method for PDCCH, an interleaved scheme and a non-interleaved scheme may be supported. The base station may configure the UE whether to use interleaved or non-interleaved transmission for each CORESET via higher layer signaling. Interleaving may be performed in units of REG bundles. A REG bundle may be defined as a collection of one or multiple REGs. The UE may determine the CCE-to-REG mapping scheme for the corresponding CORESET according to the presence or absence of interleaved or non-interleaved transmission configured by the base station in the manner shown in Table 5 below.

[0072] [Table 5]

[0073] The base station can inform the terminal of configuration information such as which symbol the PDCCH is mapped to within a slot and a transmission period through signaling.

[0074] The search space of the PDCCH will be described as follows. The number of CCEs required to transmit the PDCCH may be 1, 2, 4, 8, or 16 depending on an aggregation level (AL), and different numbers of CCEs may be used for link adaptation of the downlink control channel. For example, when AL=L, one downlink control channel may be transmitted through L CCEs. A terminal performs blind decoding to detect a signal without knowing information about the downlink control channel, and a search space indicating a set of CCEs may be defined for this purpose. The search space is a set of downlink control channel candidates consisting of CCEs that a terminal needs to attempt to decode on a given aggregation level, and since there are various aggregation levels that form one group with 1, 2, 4, 8, or 16 CCEs, a terminal may have a plurality of search spaces. A search space set may be defined as a set of search spaces at all set aggregation levels.

[0075] The search space may be classified into a common search space (CSS) and a UE-specific search space (USS). A certain group of terminals or all terminals may search the common search space of the PDCCH to receive cell-common control information such as dynamic scheduling for system information (SIB) or paging messages. For example, a terminal may receive scheduling assignment information of the PDSCH for system information reception by searching the common search space of the PDCCH. In the case of the common search space, since a certain group of terminals or all terminals need to receive the PDCCH, it may be defined as a set of pre-promised CCEs. Scheduling assignment information for the UE-specific PDSCH or PUSCH may be received by the terminal by searching the UE-specific search space of the PDCCH. The UE-specific search space may be defined UE-specifically as a function of the terminal's identity and various system parameters.

[0076] The base station can configure the configuration information for the search space of the PDCCH to the terminal through higher layer signaling (e.g., SIB, MIB, RRC signaling). For example, the base station can configure the number of PDCCH candidate groups at each aggregation level L, the monitoring period for the search space, the symbol-based monitoring occasion in the slot for the search space, the search space type (common search space or terminal-specific search space), the combination of DCI format and RNTI to be monitored in the corresponding search space, the CORESET index to be monitored for the search space, etc. to the terminal. For example, the parameters for the search space for the PDCCH can include information such as those shown in Table 6 below.

[0077] [Table 6-1] [Table 6-2] [Table 6-3] [Table 6-4] [Table 6-5]

[0078] According to the configuration information, the base station can configure one or more search space sets for the terminal. According to some embodiments, the base station can configure search space set 1 and search space set 2 for the terminal. In search space set 1, the terminal can be configured to monitor DCI format A scrambled with X-RNTI in a common search space, and in search space set 2, the terminal can be configured to monitor DCI format B scrambled with Y-RNTI in a terminal-specific search space.

[0079] According to the configuration information, one or more search space sets may exist in the common search space or the terminal-specific search space. For example, search space set #1 and search space set #2 may be set in the common search space, and search space set #3 and search space set #4 may be set in the terminal-specific search space.

[0080] In the common search space, the terminal can monitor the following DCI format and RNTI combinations, which are of course not limited to the following examples. -DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI -DCI format 2_0 with CRC scrambled by SFI-RNTI -DCI format 2_1 with CRC scrambled by INT-RNTI -DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI -DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0081] In the terminal-specific search space, the terminal can monitor the following DCI format and RNTI combinations, which are of course not limited to the following examples. -DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI -DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0082] The RNTI may adhere to the following definition and usage: C-RNTI (Cell RNTI): Used for terminal-specific PDSCH or PUSCH scheduling TC-RNTI (Temporary Cell RNTI): Used for terminal-specific PDSCH scheduling CS-RNTI (Configured Scheduling RNTI): Semi-statically configured terminal-specific PDSCH scheduling RA-RNTI (Random Access RNTI): Used for PDSCH scheduling in the random access phase P-RNTI (Paging RNTI): Used for PDSCH scheduling to transmit paging SI-RNTI (System Information RNTI): System information is transmitted for PDSCH scheduling INT-RNTI (Interruption RNTI): Used to indicate the presence or absence of puncturing for PDSCH TPC-PUSCH-RNTI (Transmit Power Control for PUSCH RNTI): Used to indicate power adjustment commands for PUSCH TPC-PUCCH-RNTI (Transmit Power Control for PUCCH RNTI): Indication of power adjustment command for PUCCH TPC-SRS-RNTI (Transmit Power Control for SRS RNTI): Used to indicate power adjustment commands for SRS

[0083] The above DCI format may be defined as shown in Table 7 below.

[0084] [Table 7]

[0085] CORESETp, the search space of the search space set s with aggregation level L can be expressed as follows:

[0086]

number

[0087] -L: Aggregation level -n CI : Carrier index -N CCE,p : The total number of CCEs in the control resource set p -n μ s,f :Slot index -M (L) p,s,max : Number of PDCCH candidate groups for aggregation level L -m snCI =0,…,M (L) p,s,max -1: PDCCH candidate set index for aggregation level L -i=0,…,L-1

number

[0088]

number

number

[0089] As a method for supporting ultra-high-speed data services, data rates can be increased by spatial multiplexing using multiple transmit and receive antennas. Generally, the number of power amplifiers (PA) required increases in proportion to the number of transmit antennas equipped in a base station or terminal. The maximum output of a base station and terminal depends on the characteristics of the power amplifier, and the maximum output of a base station generally differs depending on the cell size covered by the base station. Maximum output is usually expressed in dBm. The maximum output of a terminal is usually 23 dBm or 26 dBm.

[0090] As an example of a commercial 5G base station, the base station can operate at a bandwidth of 100 MHz by having 64 transmitting antennas and corresponding 64 power amplifiers in the 3.5 GHz frequency band. As a result, the energy consumption of the base station increases in proportion to the power amplifier output and the operation time of the power amplifier. Compared to LTE base stations, 5G base stations have a relatively high operating frequency band and are therefore characterized by having a wide bandwidth and many transmitting antennas. While these characteristics have the effect of immediately increasing the data rate, they also incur the cost of increasing the energy consumption of the base station. Therefore, the more base stations that make up a mobile communication network, the greater the energy consumption of the entire mobile communication network.

[0091] As mentioned above, the energy consumption of a base station is largely determined by the operation of the power amplifier. Since the power amplifier is involved in the transmission operation of the base station, the downlink (DL) transmission operation of the base station is highly related to the energy consumption of the base station. In comparison, the uplink (UL) reception operation of the base station does not account for a large proportion of the energy consumption of the base station. The physical channels and physical signals that the base station transmits on the downlink are as follows: -PDSCH (Physical Downlink Shared Channel): A downlink data channel including data to be transmitted to one or multiple terminals. PDCCH (Physical Downlink Control Channel): A downlink control channel including scheduling information for PDSCH and PUSCH (Physical Uplink Control Channel). Alternatively, the PDCCH alone can transmit control information such as slot format and power control command without the PDSCH or PUSCH to be scheduled. The scheduling information includes resource information to which the PDSCH or PUSCH is mapped, HARQ-related information, power control information, etc. -PBCH (Physical Broadcast Channel): A downlink broadcast channel that provides MIB (Master Information Block), which is essential system information required for transmitting and receiving data channels and control channels of a terminal. -PSS (Primary Synchronization Signal): A signal that serves as a reference for DL ​​time / frequency synchronization, providing part of the cell ID information. -SSS (Secondary Synchronization Signal): A signal that serves as a reference for DL ​​time and / or frequency (hereinafter, time / frequency) synchronization and provides the remaining part of the cell ID information. -DM-RS (Demodulation Reference Signal): A reference signal for UE channel estimation for each of PDSCH, PDCCH, and PBCH -CSI-RS (Channel-state Information Reference Signal): A downlink signal that serves as a reference for measuring the downlink channel state of a terminal. -PT-RS (Phase-tracking Reference Signal): Downlink signal for phase tracking

[0092] In terms of reducing base station energy, when a base station stops downlink transmission operation, the power amplifier operation is stopped, which can reduce the base station energy. Since the operation of the remaining base station equipment such as the baseband device as well as the power amplifier is reduced, additional energy reduction is possible. Similarly, even if the uplink reception operation accounts for a relatively small proportion of the base station's total energy consumption, if the uplink reception operation can be stopped, additional energy reduction effects can be obtained.

[0093] The downlink transmission operation of the base station is basically dependent on the amount of downlink traffic. For example, if there is no data to transmit to the terminal on the downlink, the base station does not need to transmit the PDSCH and the PDCCH for scheduling the PDSCH. Or, if the transmission can be postponed for a while because the data is not sensitive to transmission delay, the base station may not transmit the PDSCH and / or the PDCCH. Hereinafter, for convenience of explanation, the method of reducing the base station energy consumption by not transmitting or appropriately adjusting the PDSCH and / or the PDCCH related to the data traffic is referred to as "base station energy reduction method 1-1".

[0094] In contrast, physical channels and physical signals such as PSS, SSS, PBCH, and CSI-RS are characterized by being repeatedly transmitted at a predetermined scheduled period regardless of data transmission to the terminal. Therefore, even if the terminal does not receive data, it can continuously update downlink time / frequency synchronization, downlink channel state, radio link quality, etc. That is, PSS, SSS, PBCH, and CSI-RS must be transmitted to the downlink regardless of downlink data traffic, which results in energy consumption of the base station. Therefore, the base station energy can be reduced by adjusting the transmission of signals unrelated (or less related) to data traffic to occur less frequently (hereinafter referred to as "base station energy reduction method 1-2").

[0095] By using "Base Station Energy Reduction Method 1-1" or "Base Station Energy Reduction Method 1-2," the base station's energy reduction effect can be maximized by suspending or minimizing the operation of the base station's power amplifier and related RF devices, baseband devices, etc. during time periods when the base station is not transmitting downlink.

[0096] As another method, the energy consumption of the base station can be reduced by switching off some of the antennas or power amplifiers of the base station (hereinafter, "base station energy reduction method 2"). In this case, as a counteraction to the energy reduction effect of the base station, there may be an adverse effect such as a reduction in cell coverage or a reduction in throughput. For example, there may be a base station that has 64 transmitting antennas and corresponding 64 power amplifiers in the 3.5 GHz frequency band as described above and operates at a bandwidth of 100 MHz. If only four transmitting antennas and four power amplifiers are activated during a predetermined time period and the rest are switched off to reduce the energy of such a base station, the energy consumption of the base station during the corresponding time period is reduced to about 1 / 16 (= 4 / 64). If only four transmitting antennas and four power amplifiers are activated during a predetermined time period and the rest are switched off, it becomes difficult to achieve the cell coverage and throughput assuming the conventional 64 antennas and power amplifiers due to the reduction in maximum transmission power and the reduction in beamforming gain.

[0097] In the following description, to distinguish it from general base station operation, the base station mode that applies operation for reducing base station energy is referred to as a base station power saving mode (ES mode), and the base station mode that applies general base station operation is referred to as a base station normal mode (Normal mode).

[0098] As another method for supporting ultra-high-speed data services, the 5G system can support ultra-widebandwidth signal transmission and reception of tens to hundreds of MHz or several GHz. Ultra-widebandwidth signal transmission and reception can be supported via a single component carrier (CC) or a carrier aggregation (CA) technology that combines multiple component carriers. When a mobile communication operator cannot secure a frequency with a sufficient bandwidth for providing ultra-high-speed data services with a single component carrier, the carrier aggregation technology combines each component carrier with a relatively small bandwidth size to increase the total frequency bandwidth, thereby enabling ultra-high-speed data services.

[0099] FIG. 5 illustrates the interrelationship between frequency bands, coverage, and bandwidth according to an embodiment of the present disclosure. As described above, the frequency bands utilized by 5G systems are wide, ranging from hundreds of MHz to tens of GHz. In general, the lower the frequency band, the greater the coverage due to relatively low path loss, and the larger the frequency band, the smaller the coverage due to relatively high path loss. In low frequency bands, there are relatively few frequencies available for mobile communications and the bandwidth is small, whereas in high frequency bands, it is relatively easy to secure wideband frequencies, making them suitable for ultra-high speed data services. As mobile communication systems evolve, efforts are being made to discover and utilize new frequency bands. For example, although still in the early stages of discussion, there are plans to develop 6G (6 th generation) mobile communication systems use THz (Terahertz, 10 12Hz) band is considered as one of the candidate frequencies. Generally, mobile communication operators secure multiple frequency bands to provide mobile communication services to users. For example, mobile communication operators can combine the previously secured frequency band for the LTE system with the newly secured frequency band for the 5G system to operate a system that combines LTE and 5G. As another example, mobile communication operators can secure multiple frequency bands for the 5G system and then combine the frequencies of the multiple bands to provide mobile communication services through 5G CA. As mentioned above, characteristics such as coverage and bandwidth differ depending on the frequency band, so mobile communication services that combine multiple frequency bands are gradually becoming more popular than mobile communication services that rely on a single frequency band.

[0100] 6 and 7 illustrate a representative scenario of a base station deployment in which the operations of the present disclosure may be applied according to one embodiment of the present disclosure.

[0101] FIG. 6 is a diagram illustrating a base station deployment scenario according to one embodiment of the present disclosure.

[0102] Referring to FIG. 6, the carriers are composed of a carrier (hereinafter, referred to as a “macro cell” for convenience of explanation) 601 that operates at a frequency F1 and carriers (hereinafter, referred to as “small cells” 602, 603, 604, 605, 606) that operate at a frequency F1 or F2 (F1 <F2)。

[0103] It is assumed that the "macro cell" provides wide cell coverage because of its relatively high maximum output, while the "small cell" provides cell coverage limited by its relatively low maximum output. The size of the circle in FIG. 6 indicates the size of the coverage that each carrier can provide. FIG. 6 shows that a large number of "small cells" coexist within the coverage of the "macro cell". The "macro cell" and the "small cell" are connected to each other by wire or wirelessly, allowing for smooth cooperation. In the present disclosure, the base station may be in a form that combines the "macro cell" and the "small cell", or may be implemented as separate base stations for the "macro cell" and the "small cell". If the "macro cell" and the "small cell" are implemented as one base station, the "macro cell" and the "small cell" may each be referred to as a transmission reception point (TRP).

[0104] FIG. 7 is a diagram illustrating a base station deployment scenario according to one embodiment of the present disclosure.

[0105] Referring to Figure 7, a carrier aggregation system is shown in which a carrier (cell 1) operating at a frequency F1 and a carrier (cell 2) operating at a frequency F2 are combined (F1 ≠ F2). Figure 7 shows an example of applying carrier aggregation through one base station. Unlike the case of Figure 6, the cell coverage provided by each carrier is similar to each other.

[0106] The main gist of the present disclosure is to adjust the transmission power of a signal transmitted by a base station in order to reduce the energy consumption of the base station. That is, the base station transmission power in the base station general mode is adjusted to P normal When the base station transmission power in the base station power reduction mode is P energysaving Then, P normal >P energysaving The transmission power of the base station transmission signal is adjusted so as to satisfy the relationship of energysaving This can be considered as a special case of P = 0. normal, P energysaving The unit of can be expressed in Watts.

[0107] In the scenario of FIG. 6 or FIG. 7, the base station can reduce the energy consumption of the base station by adjusting the transmission power of the base station transmission signal in at least one cell among the multiple cells constituting the system. For example, in the case of FIG. 6, the base station adjusts the transmission power of at least one or more "small cells" and maintains the transmission power of the "macro cell" as it is, so that the base station can maintain the cell coverage of the "macro cell" and reduce the base station energy consumption of the "small cell". In the case of FIG. 7, the base station can maintain the cell coverage and reduce the energy consumption of the base station by adjusting the transmission power of cell 2 and maintaining the transmission power of cell 1 as it is.

[0108] Transmission power can be expressed in conjunction with bandwidth as power spectral density (PSD). The unit of PSD is usually expressed in Watt / Hz, meaning power per unit bandwidth. Transmission bandwidth means the bandwidth occupied by the signal transmitted by the base station, and can be expressed in units of MHz. EPRE (Energy Per Resource Element) can be used as a concept similar to PSD. EPRE means energy per RE. EPRE can be expressed in units of dBm.

[0109] FIG. 8 is a diagram illustrating the interrelationship of downlink signal transmission power settings according to an embodiment of the present disclosure. The interrelationship of downlink signal transmission power settings in FIG. 8 can correspond to the interrelationship of downlink signal EPRE settings in a 5G system. Basically, the base station sets the SSS EPRE, then adjusts the CSI-RS EPRE based on the SSS EPRE, and adjusts the PDSCH EPRE compared to the CSI-RS EPRE, the PT-RS EPRE compared to the PDSCH EPRE, the PDSCH DMRS EPRE compared to the PDSCH EPRE, etc. That is, the EPRE relationships of the downlink signals are linked to each other. The base station can inform the terminal of the EPRE of the downlink signal by the following method. -“ ss -PBCH-BlockPower” 801: A parameter for adjusting the EPRE of the SSS, which is notified by the base station to the terminal via signaling. It is expressed in dBm units. The PSS EPRE, PBCH EPRE, and PBCH DMRS EPRE usually apply the same value as the SSS EPRE. "powerControlOffsetSS" 802: a parameter for adjusting the power offset of CSI-RS RE and SSS RE, which is notified by the base station to the terminal via signaling. This is the ratio of CSI-RS EPRE to SSS EPRE and is expressed in dB. "powerControlOffset" 803: a parameter for adjusting the power offset of PDSCH RE and CSI-RS RE, which is notified by the base station to the terminal via signaling. This is the ratio of PDSCH EPRE to CSI-RS EPRE, and is expressed in dB. "epre-Ratio" 804: A parameter for adjusting the ratio of PT-RS EPRE and PDSCH EPRE, which is notified by the base station to the terminal via signaling. Expressed in dB. -ratio of PDSCH EPRE to PDSCH DM-RS EPRE 805: The ratio between the PDSCH EPRE and the PDSCH DM-RS EPRE is determined according to a PDSCH DM-RS configuration separately set by the base station.

[0110] Hereinafter, an operation of adjusting the transmission power of a signal transmitted by a base station proposed in the present disclosure will be described according to a specific embodiment.

[0111] First Embodiment The first embodiment describes a method for a base station to adjust the transmission power of a downlink signal.

[0112] Generally, the transmission power of downlink common signals (PSS, SSS, PBCH, CSI-RS, etc.) transmitted by a base station is determined once, taking into consideration cell coverage, etc., at the stage of installing the base station, and is maintained as is unless there are special circumstances. However, when power saving is required for the base station, a method is required for the base station to quickly change the transmission power of the downlink common signals to improve the power saving effect.

[0113] The base station can adjust the transmission power of the downlink common signal and inform the mobile station of the adjusted transmission power through the following signaling method. - Method 1 (RRC signaling): As in the conventional method, the base station can inform the terminal of the above-mentioned "ss-PBCH-BlockPower", "powerControlOffsetSS" or a corresponding value through RRC signaling. Although the signaling error probability can be significantly reduced through the HARQ and ARQ procedures, it takes a relatively long time for the signaling to be completed and applied to the terminal. - Method 2 (MAC signaling): The base station may inform the terminal of the above-mentioned "ss-PBCH-BlockPower", "powerControlOffsetSS" or a value corresponding thereto via a MAC signal. The MAC signaling may have a signaling error probability that is intermediate between the RRC signaling error probability and the physical layer signaling error probability. The MAC signaling completion time may also be intermediate between the RRC signaling time and the physical layer signaling time. - Method 3 (Physical Layer Signaling): The base station may inform the terminal of the above-mentioned "ss-PBCH-BlockPower", "powerControlOffsetSS" or a value corresponding thereto through physical layer signaling. The physical layer signaling is characterized by a fast signaling completion time but a relatively high signaling error probability. The physical layer signaling may be transmitted through a PDCCH. For example, the base station may signal through a Group common PDCCH commonly applied to multiple terminals or a PDCCH that schedules the PDSCH / PUSCH of a specific terminal. When using the Group common PDCCH, the base station may define and operate a separate CORESET, search space, DCI format, and RNTI for adjusting the transmission power of a downlink signal. For example, the base station may use a CORESET as the CORESET of the PDCCH for reducing the base station power. ES , SearchSpace is used as the search space of PDCCH for reducing base station power. ES In addition, the base station can operate by introducing DCI 2_ES, which is a DCI format of the PDCCH for reducing the base station power, and ES-RNTI, which is an RNTI for reducing the base station power. The terminal can receive the CORESET ES and the search space ES is monitored and detected using DCI format DCI 2_ES, and then descrambled using ES-RNTI to obtain signaling for reducing base station power. - Method 4 (Combination of RRC signaling and MAC signaling): The RRC signaling of method 1 and the MAC signaling of method 2 can be combined. In this case, the base station first notifies the terminal of all or part of the signaling values ​​for adjusting the transmission power of the downlink signal through RRC signaling, and additionally notifies the terminal of the transmission power value of the downlink signal that is finally applied from the signaling values ​​notified through RRC signaling through MAC signaling. Through such stepwise signaling, the base station can divide the amount of information to be signaled at one time and compromise the advantages and disadvantages of each signaling method. - Method 5 (Combination of RRC signaling and physical layer signaling): The RRC signaling of method 1 can be combined with the physical layer signaling of method 3. As in method 4, the base station can first notify the terminal of all or part of the signaling values ​​for adjusting the transmission power of the downlink signal through RRC signaling, and can additionally notify the terminal of the transmission power value of the downlink signal to be finally applied from among the signaling values ​​notified through RRC signaling through physical layer signaling. Through such stepwise signaling, the amount of information to be signaled at one time can be divided, and the advantages and disadvantages of each signaling method can be compromised. The signaling value may represent the SSS EPRE value adjusted by the base station or a value corresponding thereto, or may represent the EPRE value or a value corresponding thereto of each of the downlink common signals such as the SSS EPRE, the CSI-RS EPRE, and the PT-RS EPRE individually.The signaling value may represent the absolute value of the newly changed EPRE value, or may be expressed as a ratio or percentage of the EPRE in the base station general mode.

[0114] <Second embodiment> The second embodiment describes a method for adjusting the transmission power of CSI-RS.

[0115] In 5G systems, CSI-RS will be used for a variety of purposes, including: -CSI-RS Use 1: Reference signal (CSI measurement) for a terminal to measure downlink channel conditions -CSI-RS Use 2: Reference signal for downlink time / frequency tracking by the terminal -CSI-RS Use 3: Reference signal for supporting terminal mobility -CSI-RS Use 4: Reference signal to support rapid SCell activation in case of CA -CSI-RS Use 5: Reference signal for a terminal to measure downlink interference

[0116] In order to utilize the various CSI-RSs as described above, the base station can configure a CSI-RS resource for each CSI-RS purpose in the terminal. The CSI-RS resource includes time / frequency resource information to which the CSI-RS is mapped, and CSI-RS transmission power information such as the above-mentioned "powerControlOffsetSS".

[0117] In the second embodiment, when the base station adjusts the transmission power of a downlink signal to reduce the power of the base station, the base station adjusts the transmission power of the CSI-RS for each CSI-RS resource according to the characteristics of each CSI-RS usage.

[0118] FIG. 9 is a diagram illustrating transmission power adjustment for each CSI-RS resource according to an embodiment of the present disclosure. The transmission power adjustment for each CSI-RS resource in FIG. 9 may correspond to the transmission power adjustment for each CSI-RS resource according to the second embodiment. Referring to FIG. 9, "ss-PBCH-BlockPower" 901 adjusts the SSS EPRE. "powerControlOffsetSS" 902 indicates how much transmission power should be adjusted for each CSI-RS resource compared to the SSS EPRE. "powerControlOffset" 903 adjusts the PDSCH EPRE compared to the CSI-RS EPRE. Information on which CSI-RS resource among a plurality of CSI-RS resources the PDSCH EPRE should be adjusted compared to the CSI-RS EPRE can be additionally notified to the terminal by signaling. In the example of FIG. 9, it is shown that the PDSCH transmission power is adjusted based on CSI-RS#1. The base station notifies the terminal of “ss-PBCH-BlockPower” 901, “powerControlOffsetSS” 902, and “powerControlOffset” 903 via signaling.

[0119] <Third embodiment> In the third embodiment, a measurement report method of a terminal when a base station adjusts a transmission power of a downlink signal will be described.

[0120] UE measurement is a measurement operation performed by a terminal on the channel state between the terminal and a base station, and various measurement values ​​can be defined. The base station can control a measurement report method including a reference signal to be measured by the terminal, measurement values, a report period, a report condition, etc. by notifying the terminal of the measurement report and related configuration information in advance through signaling. The base station can refer to the measurement report received from the terminal and perform an efficient scheduling operation for the terminal, such as whether to handover the terminal to another cell. The measurement report of the terminal can be classified into an L3 measurement report and an L1 measurement report. -L3 measurement report: The L3 measurement report is a measurement report that the terminal reports to the base station in the form of upper layer layer 3 (L3) signaling, and is characterized in that the terminal performs measurements for a relatively long observation time. Therefore, it is suitable for measuring channel conditions that do not change rapidly over time. The L3 measurement report is transmitted via the PUSCH, which is a physical channel for uplink data transmission, and can store a relatively large amount of information. The following information is included in the L3 measurement report: RSRP (Reference Signal Received Power): A value indicating the received power of a reference signal, which is used to determine whether the radio link quality of a cell through which the reference signal is transmitted is maintained at a certain level or higher. The reference signal can be SSB or CSI-RS. RSRQ (Reference Signal Received Quality): A value indicating the reception quality of a reference signal, which is used to determine whether the radio link quality of a cell to which a reference signal is transmitted is maintained at a certain level or higher, similar to RSRP. The reference signal can be SSB or CSI-RS. SINR (Signal-to-noise and Interference ratio): A value indicating the ratio of received signal to interference and noise for a reference signal. The reference signal can be SSB or CSI-RS. -L1 measurement report: The L1 measurement report is a measurement report that a terminal reports to a base station in the form of physical layer layer 1 (L1) signaling, and is characterized in that the terminal performs measurements for a relatively short observation time. Therefore, it is suitable for reporting relatively instantaneous channel conditions. The reference signal to be measured by the terminal may be SSB or CSI-RS. The L1 measurement report is transmitted via PUCCH or PUSCH and can store a relatively small amount of information. The following information is included in the L1 measurement report: CQI (Channel Quality Indicator): CQI index indication information consisting of a modulation scheme and coding rate that satisfies a predefined minimum reception error rate for PDSCH PMI (Precoding Matrix Indicator): Precoding matrix indication information selected by the terminal CRI (CSI-RS resource indicator): CSI-RS information measured by the terminal · RI (Rank Indicator): Rank indicator information selected by the device LI (Layer indicator): Indication of the best layer in the precoding matrix reported by the terminal SSBRI (SS / PBCH block resource indicator): SSB information measured by the terminal L1-RSRP (Reference Signal Received Power): L1 RSRP information measured by the terminal

[0121] The terminal can perform measurement reports not only for the currently connected cell but also for neighboring cells. For measurement reports for neighboring cells, the terminal performs measurement operations on the reference signals of the neighboring cells. The terminal can report measurement reports periodically (periodic reporting) according to the base station configuration, or can report when preset conditions are met (event-triggered reporting).

[0122] As described above, the terminal performs a measurement operation for a predetermined reference signal during a predetermined observation time period for an L1 measurement report or an L3 measurement report.

[0123] However, when the base station changes the transmission power of the reference signal depending on whether the base station is in the general base station mode or the reduced base station power mode, the measurement report value and the measurement report conditions of the terminal need to be different depending on the changed transmission power of the reference signal. For example, when the transmission power P normal When this is the case, the terminal measures the RSRP for the reference signal measured by the terminal, normal The threshold THRESHOLD is a pre-determined condition for determining whether or not to report the normal Compare and judge.

[0124] In the base station power reduction mode, the transmission power of the reference signal transmitted by the base station is P ES (P ES <P normal ), the RSRP measurement value for the reference signal measured by the terminal is changed to RSRP ES is the amount of change in the transmission power of the reference signal compared to the conventional RSRP. normal In addition, the threshold value, which is the condition for determining whether or not a terminal reports the measured RSRP to the base station, will have a different range of values ​​from the conventional THRESHOLD normal If the RSRP measurement value is applied as is, it may cause an inaccurate measurement report operation of the terminal. Therefore, in the base station power reduction mode, the terminal uses the RSRP measurement value RSRP ESThe base station reports to the base station a value that has been changed by the amount of change in the transmission power of the reference signal. Similarly, the threshold value THRESHOLD ES applies.

[0125] Although the measurement reports have been described in accordance with the RSRP standard, they may be generalized and applied to other measurement reports as well. Similarly, the judgment conditions for the terminal to determine whether to report a measurement report to the base station may be defined individually for each measurement report value or measurement report event.

[0126] 10 is a diagram illustrating a measurement report procedure of a terminal according to an embodiment of the present disclosure. The measurement report procedure of the terminal in FIG. 10 can correspond to the measurement report procedure of the terminal according to the third embodiment.

[0127] 10, the terminal determines whether the base station is in a reduced power mode in step 1001. The base station can directly notify the terminal that it is in the reduced power mode through signaling, or the base station can indirectly notify the terminal that it is in the reduced power mode by notifying the terminal of an adjusted downlink transmission power value.

[0128] If the determination in step 1001 indicates that the base station is operating in a general base station mode, the terminal maintains the measurement reporting value set#1 and threshold set#1 as in the conventional method in step 1002. If the determination in step 1001 indicates that the base station is operating in a reduced power mode, the terminal applies the measurement reporting value set#2 and threshold set#2 in the reduced base station power mode in step 1003.

[0129] <Fourth embodiment> The fourth embodiment describes another method for adjusting the transmission power of a downlink signal.

[0130] According to the description of FIG. 8, it has been described that the transmission power of the downlink signal associated with the SSS can be adjusted in a linked manner by adjusting the SSS EPRE. Differently, in the fourth embodiment, a method in which the base station adjusts the transmission power of the downlink signal independently of the SSS is described. In particular, in the fourth embodiment, a method in which the base station adjusts the transmission power of the PDCCH and PDSCH, which are UE-specific signals, without changing the transmission power of the downlink common signal is described. As described above, the downlink common signal including the SSS is a main signal that determines the cell coverage, and in some cases, it may not be preferable for the base station to change the transmission power. For example, unlike the scenario of FIG. 6 or FIG. 7, when a system is configured with one cell, there may be cases in which another method for restoring the cell coverage reduction caused by the base station changing the transmission power of the downlink common signal may not be provided.

[0131] Unlike downlink common signals, the PDCCH and PDSCH transmitted to each terminal can offset the impact of coverage reduction by changing the transmission bandwidth or transmission antenna according to scheduling even if the base station changes the transmission power. However, in the case of downlink common signals, most of the transmission formats such as the transmission bandwidth and transmission antenna are fixed, so there is almost no room for change.

[0132] Therefore, in the fourth embodiment, the base station adjusts the transmission power for the UE-specific PDCCH and PDSCH, and the PDCCH DMRS and PDSCH DMRS, and notifies the UE through signaling. When the UE receives the UE-specific PDCCH, PDSCH, PDCCH DMRS, and PDSCH DMRS, the UE processes the UE by reflecting the changed transmission power. The UE processing includes channel estimation, PDCCH decoding, PDSCH decoding, etc. Even if the PDCCH and PDSCH are transmitted cell-specific, the base station maintains the conventional transmission power as it is, and the UE also processes the PDCCH and PDSCH according to the conventional transmission power. Whether the PDCCH and PDSCH are UE-specific signals or cell-common signals can be determined by the RNTI that scrambles the corresponding channel. For example, the PDCCH and PDSCH scrambled with the C-RNTI are terminal-specific signals, whereas the PDCCH and PDSCH scrambled with the SI-RNTI are cell-common signals carrying system information. The specific method of the first embodiment described above may be applied to the signaling method for adjusting the transmission power of the UE-specific PDCCH and PDSCH, and the PDCCH DMRS and PDSCH DMRS. Since the UE-specific PDCCH and PDSCH can be transmitted only to a terminal in a connected state where the base station has completed an initial access procedure, the method for changing the transmission power of the PDCCH / PDSCH is not applied to terminals that have not yet completed an initial access procedure or terminals that are not in a connected state.

[0133] 11 is a diagram illustrating a terminal procedure for changing a downlink signal transmission power according to an embodiment of the present disclosure. The terminal procedure for changing a downlink signal transmission power in FIG. 11 may correspond to the terminal procedure according to the fourth embodiment.

[0134] 11, the terminal determines whether the base station is in a reduced power mode in step 1101. The base station can notify the terminal that it is in the reduced power mode directly or indirectly through signaling.

[0135] If the determination result in step 1101 is that the base station operates in the base station general mode, in step 1102, the terminal performs reception processing for the downlink signal based on the transmission power of the base station general mode. If the determination result in step 1101 is that the base station operates in the power reduction mode, in step 1103, the terminal determines whether the signal received from the base station is a cell common signal. If it is a cell common signal, the procedure of step 1102 can be performed for the cell common signal. If the determination result in step 1103 is that it is a terminal specific signal, in step 1104, the terminal performs reception processing for the PDCCH and PDSCH reflecting the adjusted transmission power.

[0136] <Fifth embodiment> In the fifth embodiment, an example of a terminal procedure and a base station procedure according to a preferred embodiment of the present disclosure will be described. The terminal procedure and the base station procedure of the fifth embodiment may be performed in combination with at least one of the first embodiment to the fourth embodiment.

[0137] 12 is a flowchart for explaining a terminal procedure according to an embodiment of the present disclosure. Specifically, FIG. 12 is a flowchart for a terminal procedure to be applied when a base station switches to a base station power reduction mode or a base station general mode.

[0138] 12, in step 1201, the terminal reports UE capability information including base station power reduced mode support capability to the base station. Specifically, the UE capability information may include at least one of capability information related to the base station power reduced mode, such as information indicating whether the terminal supports the base station power reduced mode, control information related to frequency bands supported by the terminal, and control information related to channel bandwidths supported by the terminal.

[0139] Thereafter, in step 1202, if the terminal successfully acquires signaling from the base station to change the base station mode to the base station power reduction mode, the terminal changes the terminal configuration according to the instructed base station power reduction mode. The signaling may include at least one of configuration information related to the base station power reduction mode, such as information on the base station transmission power to be changed according to the base station power reduction mode, configuration information on physical channels and physical signals whose transmission characteristics are changed, and terminal measurement configuration information for measurement reporting.

[0140] Alternatively, in step 1202, the terminal may receive signaling from the base station to change from the base station power reduction mode to the base station general mode, in which case the signaling may include at least one of setting information related to the base station general mode, such as information on the base station transmission power to be changed in the base station general mode, setting information on physical channels and physical signals whose transmission characteristics are changed, terminal measurement setting information for measurement reporting, etc. Also, information that may be included in the base station mode change signaling may be preset in the terminal by higher-level signaling.

[0141] In step 1203, if the terminal successfully acquires the "base station mode change signaling", the terminal transmits "base station mode change signaling response" control information to the base station. The transmission of the control information may be omitted.

[0142] In step 1204, the terminal completes updating of related terminal settings according to the "base station mode change command". According to one embodiment, the terminal that receives the signaling can change hardware settings or software settings of an RF device, a baseband device, etc. that operate according to the changed base station transmission power. From step 1205, the terminal performs transmission and reception operations according to the changed base station mode. Specific terminal transmission and reception operations according to the base station mode are according to the above-mentioned embodiment.

[0143] The present disclosure may be practiced with steps described with respect to FIG. 12 omitted, reordered, or with steps added that are not described.

[0144] 13 is a flowchart for explaining a base station procedure according to an embodiment of the present disclosure. Specifically, FIG. 13 is a flowchart for a base station procedure to be applied when the base station switches to a base station power reduction mode or a base station general mode.

[0145] 13, in step 1301, the base station obtains UE capability information including base station power reduced mode support capability from the terminal. Specifically, the UE capability information may include at least one of capability information related to the base station power reduced mode, such as information indicating whether the terminal supports the base station power reduced mode, control information related to frequency bands supported by the terminal, and control information related to channel bandwidths supported by the terminal.

[0146] Thereafter, in step 1302, the base station performing the mode change transmits "base station mode change signaling" to the terminal. According to an embodiment, when the signaling is for changing from the base station general mode to the base station reduced power mode, the signaling may include at least one of setting information related to the base station reduced power mode, such as information on the base station transmission power to be changed due to the base station reduced power mode, setting information on physical channels and physical signals whose transmission characteristics are changed, and terminal measurement setting information for measurement reporting.

[0147] Alternatively, the base station may transmit signaling to the terminal to change from the base station power reduction mode to the base station general mode in step 1302, in which case the signaling may include at least one of setting information related to the base station general mode, such as information on the base station transmission power to be changed according to the base station general mode, setting information on physical channels and physical signals whose transmission characteristics are changed, terminal measurement setting information for measurement reporting, etc. Also, information that may be included in the base station mode change signaling may be preset in the terminal by higher-level signaling.

[0148] In step 1303, the base station successfully acquires the "base station mode change signaling response" control information from the terminal. Step 1303 may be omitted.

[0149] In step 1304, the base station performs a scheduling operation according to the changed base station mode. According to an embodiment, the base station in the base station power reduction mode can transmit a downlink signal with a reduced transmission power according to the base station power reduction mode to the terminal. The specific base station transmission and reception operation according to the base station mode is according to the above-mentioned embodiment.

[0150] The present disclosure may be practiced with steps described with respect to FIG. 13 omitted, reordered, or with steps added that are not described.

[0151] Also, the methods described in FIGS. 12 and 13 may be combined with the first to fourth embodiments.

[0152] In a cell under the jurisdiction of a base station operating as described above, a terminal (hereinafter referred to as terminal A) that supports terminal operation in the base station power reduction mode and a terminal (hereinafter referred to as terminal B) that does not may coexist. In the case of terminal A, the terminal operation according to the specific embodiment described above may be performed. In the case of terminal B, since it is not possible to respond to a change in the base station transmission method due to the base station power reduction mode, there is a risk of performance degradation in transmission efficiency, cell capacity, throughput, terminal power consumption, etc. Therefore, if the base station can distinguish whether it is terminal A or terminal B by referring to the UE capability report of the terminal, it can take additional operations to prevent performance degradation of terminal B. For example, the base station can handover terminal B to a neighboring cell where a base station in a base station general mode is located, rather than the current cell that will switch to the base station power reduction mode.

[0153] Various modifications are possible to the fifth embodiment. For example, the step of the terminal reporting the UE capability to the base station may be omitted.

[0154] As another modification of the fifth embodiment, the base station may operate without separately notifying the terminal of the "base station mode change signaling". That is, the terminal does not need to distinguish whether the base station is currently in the base station normal mode or the base station power reduction mode, and can simply perform transmission and reception operations according to the base station scheduling.

[0155] 14 is a diagram illustrating a terminal transceiver device in a wireless communication system according to an embodiment of the present disclosure. For convenience of explanation, illustration and explanation of devices not directly related to the present disclosure may be omitted.

[0156] 14, the terminal may include a transmitter 1404 including an uplink transmit processing block 1401, a multiplexer 1402, and a transmit RF block 1403, a receiver 1408 including a downlink receive processing block 1405, a demultiplexer 1406, and a receive RF block 1407, and a controller 1409. The controller 1409 may control each component block of the receiver 1408 for receiving a data channel or a control channel transmitted by the base station as described above, and each component block of the transmitter 1404 for transmitting an uplink signal.

[0157] In the transmitter 1404 of the terminal, an uplink transmission processing block 1401 can generate a signal to be transmitted by performing processes such as channel coding and modulation. The signal generated in the uplink transmission processing block 1401 can be multiplexed with other uplink signals by a multiplexer 1402, and then processed in a transmission RF block 1403 before being transmitted to a base station.

[0158] The receiver 1408 of the terminal demultiplexes signals received from the base station and distributes them to each downlink receiver processing block. The downlink receiver processing block 1405 performs processes such as demodulation and channel decoding on the downlink signal of the base station to obtain control information or data transmitted by the base station. The receiver 1408 of the terminal applies the output result of the downlink receiver processing block to the controller 1409 to support the operation of the controller 1409.

[0159] FIG. 15 is a block diagram illustrating a structure of a terminal according to one embodiment of the present disclosure.

[0160] Referring to FIG. 15, the terminal of the present disclosure may include a processor 1530, a transceiver 1510, and a memory 1520. However, the components of the base station are not limited to the above example. For example, the terminal may include more or fewer components than the above components. Furthermore, the processor 1530, the transceiver 1510, and the memory 1520 may be implemented in the form of a single chip. According to an embodiment, the transceiver 1510 of FIG. 15 may include the transmitter 1404 and the receiver 1408 of FIG. 14. Also, the processor 1530 of FIG. 15 may include the controller 1409 of FIG. 14.

[0161] According to an embodiment, the processor 1530 can control a series of processes by which the base station can operate according to the embodiment of the present disclosure described above. For example, according to the embodiment of the present disclosure, the components of the terminal can be controlled to perform a terminal transmission / reception method depending on whether the base station mode is a base station power reduction mode or a base station general mode. The processor 1530 can be one or more, and the processor 1530 can perform a terminal transmission / reception operation in the wireless communication system employing the carrier aggregation of the present disclosure described above by executing a program stored in the memory 1520.

[0162] The transceiver 1510 can transmit and receive signals to and from a base station. The signals transmitted and received to and from the base station can include control information and data. The transceiver 1510 can be configured with an RF transmitter that upconverts and amplifies the frequency of a signal to be transmitted, an RF receiver that performs low-noise amplification and downconverts the frequency of a received signal, and the like. However, this is merely an example of the transceiver 1510, and the components of the transceiver 1510 are not limited to an RF transmitter and an RF receiver. In addition, the transceiver 1510 can receive signals via a wireless channel, output them to the processor 1530, and transmit the signals output from the processor 1530 via a wireless channel.

[0163] According to an embodiment, the memory 1520 may store programs and data necessary for the operation of the terminal. Also, the memory 1520 may store control information or data included in a signal transmitted or received by the terminal. The memory 1520 may be configured as a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. Also, there may be a plurality of memories 1520. According to an embodiment, the memory 1520 may store a program for performing transmission and reception operations of the terminal depending on whether the base station mode, which is an embodiment of the present disclosure described above, is a base station power reduction mode or a base station general mode.

[0164] FIG. 16 is a block diagram illustrating a structure of a base station according to one embodiment of the present disclosure.

[0165] Referring to FIG. 16, the base station of the present disclosure may include a processor 1630, a transceiver 1610, and a memory 1620. However, the components of the base station are not limited to the above examples. For example, the base station may include more or fewer components than the above components. Furthermore, the processor 1630, the transceiver 1610, and the memory 1620 may be implemented in the form of a single chip.

[0166] The processor 1630 can control a series of processes so that the base station can operate according to the embodiment of the present disclosure described above. For example, the components of the base station can be controlled to perform a method for scheduling a terminal depending on whether the base station mode is a base station reduced power mode or a base station general mode according to the embodiment of the present disclosure. The processor 1630 can be one or more, and the processor 1630 can execute a program stored in the memory 1620 to perform the method for scheduling a terminal depending on whether the base station mode is a base station reduced power mode or a base station general mode described above according to the present disclosure.

[0167] The transceiver 1610 can transmit and receive signals to and from a terminal. The signals transmitted and received to and from the terminal can include control information and data. The transceiver 1610 can be configured with an RF transmitter that upconverts and amplifies the frequency of a signal to be transmitted, an RF receiver that performs low-noise amplification and downconverts the frequency of a received signal, and the like. However, this is merely an example of the transceiver 1610, and the components of the transceiver 1610 are not limited to an RF transmitter and an RF receiver. In addition, the transceiver 1610 can receive signals via a wireless channel, output them to the processor 1630, and transmit the signals output from the processor 1630 via a wireless channel.

[0168] According to an embodiment, the memory 1620 may store programs and data necessary for the operation of the base station. Also, the memory 1620 may store control information or data included in a signal transmitted or received by the base station. The memory 1620 may be configured as a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. Also, there may be a plurality of memories 1620. According to an embodiment, the memory 1620 may store a program for performing a method for scheduling a terminal depending on whether the base station mode is a base station power reduction mode or a base station general mode, which is an embodiment of the present disclosure described above.

[0169] FIG. 17 is a flowchart illustrating a base station procedure according to one embodiment of the present disclosure.

[0170] 17, in step 1701, a base station may receive a signal including terminal capability information from a terminal. The terminal capability information may include at least one of support information regarding a power reduction mode for the base station, control information related to a frequency band supported by the terminal, and power information related to a channel bandwidth supported by the terminal.

[0171] In step 1703, the base station may identify a base station mode based on the terminal capability. For example, the base station mode may be one of a reduced power mode for the base station or a general mode for the base station. At least one of information on the base station transmission power, configuration information on physical channels and physical signals whose transmission characteristics are changed, and terminal measurement configuration information for measurement reporting may be changed by changing the base station mode. Information that may be included by changing the base station mode may also be preset in the terminal by upper signaling. The magnitude of the transmission power in the reduced power mode for the base station may be set to be smaller than the magnitude of the transmission power in the general mode for the base station.

[0172] In step 1705, the base station may transmit a base station mode change signal to the terminal based on the base station mode. For example, the base station mode change signal may be one of a signal causing the terminal to change from a conventional mode to a reduced power mode for the base station or a signal causing the terminal to change from a conventional mode to a general mode for the base station. The conventional mode may be one of a reduced power mode for the base station or a general mode for the base station.

[0173] In step 1707, the base station may receive a response signal from the terminal.

[0174] In step 1709, the base station may change the magnitude of the transmission power based on the base station mode and transmit a signal to the terminal. For example, the base station mode may be one of a power reduction mode for the base station or a general mode for the base station. At least one of information on the base station transmission power, configuration information on a physical channel and a physical signal whose transmission characteristics are changed, and terminal measurement configuration information for measurement reporting may be changed by changing the base station mode. In addition, information that may be included by changing the base station mode may be preset in the terminal by upper signaling. The magnitude of the transmission power in the power reduction mode for the base station may be set to be smaller than the magnitude of the transmission power in the general mode for the base station.

[0175] According to various embodiments of the present disclosure, there is provided a method performed by a terminal in a wireless communication system, comprising: transmitting a signal including UE capability information of the terminal to a base station; and the UE capability information includes information regarding whether the terminal supports a first mode corresponding to a power saving mode of the base station; The method may include the steps of: receiving information regarding a mode of the base station from the base station in response to the capability information of the terminal; the information regarding the mode of the base station includes any one of information indicating that the mode of the base station is the first mode and information indicating that the mode of the base station is a second mode corresponding to a general mode, and a transmission power of the base station in the first mode is lower than a transmission power of the base station in the second mode; updating a configuration of the terminal to communicate with a base station in the first mode or a base station in the second mode based on the information regarding the mode of the base station; receiving a first signal from the base station based on the updated terminal configuration; and transmitting a second signal to the base station in response to the first signal.

[0176] According to an embodiment of the present disclosure, when the mode of the base station is the first mode, The transmission power of the first signal may be based on adjustment of at least one of a transmission power of a secondary synchronization signal (SSS) transmitted by the base station, a transmission power associated with a channel status information-reference signal (CSI-RS), a transmission power associated with a physical downlink shared channel (PDSCH) transmitted by the base station, a transmission power associated with a phase tracking reference signal (PTRS), or a transmission power associated with a PDSCH demodulation reference signal (DMRS).

[0177] According to one embodiment of the present disclosure, the transmission power associated with the CSI-RS transmitted by the base station is determined by the use of the CSI-RS, and the use of the CSI-RS may include at least one of a reference signal for the terminal to measure a downlink channel state, a reference signal for the terminal to track at least one of the time or frequency of the downlink, a reference signal for supporting the mobility of the terminal, a reference signal for supporting rapid SCell (secondary cell) activation of the terminal, and a reference signal for the terminal to measure the downlink interference.

[0178] According to an embodiment of the present disclosure, when the mode of the base station is the first mode, a measurement report value for the base station and a threshold corresponding to a condition for reporting a measurement for the base station may be adjusted.

[0179] According to an embodiment of the present disclosure, when the mode of the base station is the first mode, the transmission power of the first signal may be based on adjustment of at least one of a transmission power associated with a UE-specific PDSCH transmitted by the base station, a UE-specific physical downlink control channel (PDCCH), a UE-specific PDSCH DMRS, or a transmission power associated with a UE-specific PDCCH DMRS, excluding a transmission power of a downlink common signal.

[0180] According to various embodiments of the present disclosure, a method performed by a base station in a wireless communication system may include the steps of: receiving a signal including UE capability information from a terminal; the UE capability information including information on whether the terminal supports a first mode corresponding to a power reduction mode of the base station; transmitting information regarding the mode of the base station to the terminal in response to the terminal capability information; the information regarding the mode of the base station including any one of information indicating that the mode of the base station is the first mode and information indicating that the mode of the base station is a second mode corresponding to a general mode, and a transmission power of the base station in the first mode is lower than a transmission power of the base station in the second mode; adjusting a transmission power based on the information regarding the mode of the base station; transmitting a first signal to the terminal based on the adjusted transmission power; and receiving a second signal from the terminal in response to the first signal.

[0181] According to one embodiment of the present disclosure, when the mode of the base station is the first mode, the process of adjusting the transmission power based on the information regarding the mode of the base station may include a process of adjusting at least one of a transmission power of a secondary synchronization signal (SSS) transmitted by the base station, a transmission power associated with a channel status information-reference signal (CSI-RS), a transmission power associated with a physical downlink shared channel (PDSCH), a transmission power associated with a phase tracking reference signal (PTRS), or a transmission power associated with a PDSCH demodulation reference signal (DMRS).

[0182] According to one embodiment of the present disclosure, the transmission power associated with the CSI-RS transmitted by the base station is determined by the use of the CSI-RS, and the use of the CSI-RS may include at least one of a reference signal for the terminal to measure a downlink channel state, a reference signal for the terminal to track at least one of the time or frequency of the downlink, a reference signal for supporting the mobility of the terminal, a reference signal for supporting rapid SCell (secondary cell) activation of the terminal, and a reference signal for the terminal to measure the downlink interference.

[0183] According to an embodiment of the present disclosure, when the mode of the base station is the first mode, a measurement report value for the base station and a threshold corresponding to a condition for reporting a measurement for the base station may be adjusted.

[0184] According to an embodiment of the present disclosure, when the mode of the base station is the first mode, the process of adjusting the transmission power based on the information on the mode of the base station may adjust at least one of a transmission power associated with a UE-specific PDSCH transmitted by the base station, a UE-specific physical downlink control channel (PDCCH), a UE-specific PDSCH DMRS, or a transmission power associated with a UE-specific PDCCH DMRS, excluding a transmission power of a downlink common signal.

[0185] According to various embodiments of the present disclosure, a terminal in a wireless communication system includes a transceiver and at least one processor connected to the transceiver, wherein the at least one processor may be configured to: transmit a signal including UE capability information of the terminal to a base station, the terminal capability information including information regarding whether the terminal supports a first mode corresponding to a power reduction mode of the base station; receive information regarding the mode of the base station from the base station in response to the terminal capability information, the information regarding the mode of the base station including any one of information indicating that the mode of the base station is the first mode and information indicating that the mode of the base station is a second mode corresponding to a general mode, and a transmission power of the base station in the first mode is lower than a transmission power of the base station in the second mode; communicate with a base station in the first mode or update a configuration of the terminal to communicate with a base station in the second mode based on the information regarding the mode of the base station; receive a first signal based on the updated terminal configuration from the base station; and transmit a second signal to the base station in response to the first signal.

[0186] According to various embodiments of the present disclosure, a base station in a wireless communication system may be configured to receive a signal including UE capability information from a terminal, the UE capability information including information regarding whether the terminal supports a first mode corresponding to a power reduction mode of the base station, transmit information regarding the mode of the base station to the terminal in response to the terminal capability information, the information regarding the mode of the base station including any one of information indicating that the mode of the base station is the first mode and information indicating that the mode of the base station is a second mode corresponding to a general mode, and a transmission power of the base station in the first mode is lower than a transmission power of the base station in the second mode, adjust a transmission power based on the information regarding the mode of the base station, transmit a first signal to the terminal based on the adjusted transmission power, and receive a second signal from the terminal in response to the first signal.

[0187] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0188] In the case of a software implementation, a computer-readable storage medium may be provided that stores one or more programs (software modules). The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to execute a method according to the embodiments described in the claims or specification of the present disclosure.

[0189] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (Read Only Memory), Electrically Erasable Programmable Read Only Memory (EEPROM), magnetic disc storage device, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs) or other forms of optical storage, magnetic cassette, or in a memory configured as a combination of some or all of these. Also, each of the constituent memories may include multiple pieces.

[0190] The program may also be stored in an attachable storage device that can be accessed through a communication network such as the Internet, an Intranet, a Local Area Network (LAN), a Wide LAN (WLAN), or a Storage Area Network (SAN), or a combination thereof. Such a storage device can be accessed by an apparatus that performs an embodiment of the present disclosure through an external port. A separate storage device on the communication network can also be accessed by an apparatus that performs an embodiment of the present disclosure.

[0191] In the above-described specific embodiments of the present disclosure, the components included in the present disclosure are expressed in the singular or plural form according to the specific embodiments presented. However, the expressions singular or plural are selected to suit the presented circumstances for the convenience of explanation, and the present disclosure is not limited to the singular or plural components, and the components expressed in the plural form may be composed in the singular form, and the components expressed in the singular form may be composed in the plural form.

[0192] Meanwhile, the embodiments of the present disclosure disclosed in this specification and the drawings merely present specific examples to easily explain the technical contents of the present disclosure and to aid in the understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. Although specific terms are used, these are merely used in a general sense to easily explain the technical contents of the present disclosure and to aid in the understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. In addition, it is obvious to a person having ordinary knowledge in the technical field to which the present disclosure belongs that other modifications based on the technical idea of ​​the present disclosure can be implemented. In addition, each of the above embodiments can be operated in combination with each other as necessary. For example, a base station and a terminal can be operated by combining parts of one embodiment different from one embodiment of the present disclosure with each other. In addition, the embodiments of the present disclosure can be applied to other communication systems, and other modifications based on the technical idea of ​​the embodiments can also be implemented. [Explanation of symbols]

[0193] 105 Subframe 106 Slots 112 Resource Element 114 Frames 201 points 202 points 205 Terminal 1 206 Terminal 2 310 First Step 320 Second Step 330 Third Step 340 Fourth Step 401 Terminal 402 Base Station 410 Steps 420 Steps 1001 Steps 1002 Steps 1003 Steps 1101 Step 1102 Steps 1103 Steps 1104 Steps 1201 Steps 1202 Steps 1203 Steps 1204 Steps 1205 Steps 1301 Steps 1302 Steps 1303 Steps 1304 Steps 1401 Uplink Transmit Processing Block 1402 Multiplexer 1403 Transmit RF Block 1404 Transmitter 1405 Downlink Receive Processing Block 1406 Demultiplexer 1407 Receive RF Block 1408 Receiving section 1409 Control Unit 1510 Transmitter / Receiver 1520 Memory 1530 Processor 1610 Transmitter / receiver 1620 Memory 1630 processor 1701 Steps 1703 Steps 1705 Steps 1707 Steps 1709 Steps

Claims

1. A method performed by the UE (user equipment) of a wireless communication system, Steps include receiving setting information from a base station for a first power offset parameter related to the ratio of PDSCH (physical downlink shared channel) EPRE (energy per resource element) to CSI-RS (channel state information reference signal) EPRE, and a second power offset parameter related to adjusting the ratio of the PDSCH EPRE to CSI-RS EPRE; The steps of receiving CSI-RS from the base station; and A method comprising the step of transmitting channel quality information (CQI) to the CSI-RS to the base station based on the first power offset parameter and the second power offset parameter.

2. The method described above is: The step further includes receiving a PDSCH from the base station, The method according to claim 1, wherein the PDSCH power adjusted based on the first power offset parameter and the second power offset parameter is less than or equal to the PDSCH power adjusted based on the first power offset parameter.

3. The method according to claim 1, wherein the second power offset parameter includes information relating to the ratio of the PDSCH power adjusted based on the first power offset parameter to the PDSCH power adjusted based on the first power offset parameter and the second power offset parameter.

4. The method described above is: The method according to claim 1, further comprising the step of transmitting terminal capability (UE capability) information to the base station indicating whether PDSCH reception based on the second power offset parameter is supported.

5. A method performed by a base station of a wireless communication system, Steps include transmitting setting information to the UE (user equipment) for a first power offset parameter related to the ratio of PDSCH (physical downlink shared channel) EPRE (energy per resource element) to CSI-RS (channel state information reference signal) EPRE, and a second power offset parameter related to adjusting the ratio of the PDSCH EPRE to CSI-RS EPRE; The steps of transmitting CSI-RS to the UE; and A method comprising the step of receiving channel quality information (CQI) for the CSI-RS from the UE based on the first power offset parameter and the second power offset parameter.

6. The method described above is: The further step includes transmitting PDSCH to the UE, The method according to claim 5, wherein the PDSCH power adjusted based on the first power offset parameter and the second power offset parameter is less than or equal to the PDSCH power adjusted based on the first power offset parameter.

7. The method according to claim 5, wherein the second power offset parameter includes information relating to the ratio of the PDSCH power adjusted based on the first power offset parameter to the PDSCH power adjusted based on the first power offset parameter and the second power offset parameter.

8. The method described above is: The method according to claim 5, further comprising the step of transmitting terminal capability (UE capability) information from the UE indicating whether PDSCH reception based on the second power offset parameter is supported.

9. In the UE (user equipment) of a wireless communication system, At least one transceiver; A processor communicatively coupled to the at least one transceiver; and It includes at least one memory that is communicatively coupled to the at least one processor and stores a plurality of instructions, The plurality of instructions are executed individually or in any combination by the at least one processor, and the UE is: Setting information for a first power offset parameter related to the ratio of PDSCH (physical downlink shared channel) EPRE (energy per resource element) to CSI-RS (channel state information reference signal) EPRE and a second power offset parameter related to adjusting the ratio of the PDSCH EPRE to CSI-RS EPRE is received from the base station. The CSI-RS is received from the aforementioned base station. A UE that transmits channel quality information (CQI) to the CSI-RS to the base station based on the first power offset parameter and the second power offset parameter.

10. The plurality of commands cause the UE to receive PDSCH from the base station, The UE according to claim 9, wherein the PDSCH power adjusted based on the first power offset parameter and the second power offset parameter is less than or equal to the PDSCH power adjusted based on the first power offset parameter.

11. The UE according to claim 9, wherein the second power offset parameter includes information relating to the ratio of the PDSCH power adjusted based on the first power offset parameter to the PDSCH power adjusted based on the first power offset parameter and the second power offset parameter.

12. The UE according to claim 9, wherein the plurality of commands transmit terminal capability (UE capability) information to the base station indicating whether PDSCH reception based on the second power offset parameter is supported.

13. In a base station of a wireless communication system, At least one transceiver; A processor communicatively coupled to the at least one transceiver; and It includes at least one memory that is communicatively coupled to the at least one processor and stores a plurality of instructions, The plurality of instructions are executed individually or in any combination by the at least one processor, and the base station: Setting information for a first power offset parameter related to the ratio of PDSCH (physical downlink shared channel) EPRE (energy per resource element) to CSI-RS (channel state information reference signal) EPRE and a second power offset parameter related to adjusting the ratio of the PDSCH EPRE to CSI-RS EPRE is transmitted to the UE (user equipment). The CSI-RS is transmitted to the aforementioned UE, A base station that receives channel quality information (CQI) for the CSI-RS from the UE based on the first power offset parameter and the second power offset parameter.

14. The plurality of commands cause the base station to transmit PDSCH to the UE, The base station according to claim 13, wherein the PDSCH power adjusted based on the first power offset parameter and the second power offset parameter is less than or equal to the PDSCH power adjusted based on the first power offset parameter.

15. The base station according to claim 13, wherein the second power offset parameter includes information relating to the ratio of the PDSCH power adjusted based on the first power offset parameter to the PDSCH power adjusted based on the first power offset parameter and the second power offset parameter.

16. The base station according to claim 13, wherein the plurality of instructions transmit terminal capability (UE capability) information from the UE indicating whether PDSCH reception based on the second power offset parameter is supported.

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