Method and device for energy saving in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. The present disclosure provides a method and device for saving energy of a base station.

Description

Method and device for energy saving in wireless communication system

[0001] The present disclosure relates to a method and device for energy saving in a wireless communication system.

[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 frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band called millimeter wave (mmWave) such as 28GHz and 39GHz ('Above 6GHz'). In addition, for 6G mobile communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz band (for example, the 3 terahertz (3THz) band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low latency time that is reduced to one-tenth.

[0003] In the early stages of 5G mobile communication technology, the goal is to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (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 multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and Polar Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

[0004] Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology in consideration of the services that 5G mobile communication technology was intended to support, and physical layer standardization is in progress for technologies such as V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience based on their own location and status information transmitted by vehicles, NR-U (New Radio Unlicensed) for the purpose of system operation that complies with various regulatory requirements in unlicensed bands, NR terminal low power consumption technology (UE Power Saving), Non-Terrestrial Network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with terrestrial networks is impossible, and Positioning.

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

[0006] Once these 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G mobile communication systems and integrated operation of these connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] In addition, the development of these 5G mobile communication systems includes new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), Array Antenna, and Large Scale Antenna, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that exceeds the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0008] With the recent development of environmentally conscious 5G / 6G communication systems, the need for methods to reduce energy consumption at base stations is emerging.

[0009] Various embodiments of the present disclosure provide a new cell definition and on-demand cell activation method through a wake-up signal (WUS) transmitted by a terminal to reduce energy consumption of a base station in a wireless communication system.

[0010] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure pertains from the description below.

[0011] In various embodiments, a method for reducing energy consumption of a base station by a base station in a wireless communication system may include an operation in which the base station activates a cell for access or synchronization (e.g., an Access / Sync cell) and deactivates an on-demand cell for traffic (or packet) processing (e.g., a Data cell), an operation in which the base station sets configuration information for a WUS or the like for activating an on-demand cell to terminals that have performed an initial access (or, RACH procedure) through the Access / Sync cell through upper layer signaling and L1 signaling, and a method in which the terminal activates the on-demand cell based on the configuration.

[0012] In various embodiments, a method for reducing energy consumption of a base station by a terminal in a wireless communication system may include an operation in which the terminal performs an initial connection (or RACH procedure) to an Access / Sync cell, an operation in which the terminal receives configuration information of an on-demand cell for processing traffic (or packets) from the base station through upper layer signaling, and an operation in which a WUS for activating the on-demand cell is transmitted based on the received information.

[0013] In addition, a method performed by a terminal of a communication system comprises the steps of: performing an initial connection procedure with a first base station corresponding to a first cell; receiving wake-up signal (WUS) configuration information from the first base station; transmitting a WUS to a second base station corresponding to a second cell based on the WUS configuration information; and monitoring a response signal (acknowledgement) corresponding to the WUS during a WUS response window, wherein the WUS configuration information includes at least one of carrier frequency information of the second cell, WUS transmission time (occasion) information, WUS format information, and WUS response window configuration information.

[0014] In addition, a method performed by a first base station corresponding to a first cell of a communication system, comprising: performing an initial connection procedure with a terminal; and transmitting wake-up signal (WUS) configuration information to the terminal, wherein the first base station corresponding to the first cell is connected to a second base station corresponding to a second cell, and a WUS according to the WUS configuration information is transmitted from the terminal to the second base station, and the WUS configuration information includes at least one of carrier frequency information of the second cell, WUS transmission time (occasion) information, WUS format information, and WUS response window configuration information.

[0015] In addition, a method performed by a second base station corresponding to a second cell of a communication system includes the steps of: receiving a wake-up signal (WUS) from a terminal; transmitting an acknowledgment signal for the WUS to the terminal during a WUS response window; and performing an access procedure for the terminal and the second cell, wherein WUS-related information is transmitted from the second base station to a first base station corresponding to the first cell, and the WUS-related information includes at least one of carrier frequency information of the second cell, WUS transmission occasion information, WUS format information, and WUS response window setting information.

[0016] In addition, in a terminal of a communication system, a transceiver; and a control unit connected to the transceiver and including one or more processors, wherein the control unit is configured to perform an initial connection procedure with a first base station corresponding to a first cell, receive wake-up signal (WUS) configuration information from the first base station, transmit a WUS to a second base station corresponding to a second cell based on the WUS configuration information, and monitor a response signal (acknowledgement) corresponding to the WUS during a WUS response window, wherein the WUS configuration information includes at least one of carrier frequency information of the second cell, WUS transmission occasion information, WUS format information, and WUS response window configuration information.

[0017] In addition, in a first base station corresponding to a first cell of a communication system, a transceiver; and a control unit connected to the transceiver and including one or more processors, wherein the control unit is configured to perform an initial connection procedure with a terminal and transmit wake-up signal (WUS) configuration information to the terminal, and the first base station corresponding to the first cell is connected to a second base station corresponding to a second cell, and a WUS according to the WUS configuration information is transmitted from the terminal to the second base station, and the WUS configuration information includes at least one of carrier frequency information, WUS transmission occasion information, WUS format information, and WUS response window configuration information of the second cell, and the first cell corresponds to a cell type for connection and synchronization, and the second cell corresponds to a cell type for data transmission and reception.

[0018] In addition, in a second base station corresponding to a second cell of a communication system, a transceiver; and a control unit connected to the transceiver and including one or more processors, wherein the control unit is configured to: receive a wake-up signal (WUS) from a terminal, transmit an acknowledgement signal for the WUS to the terminal during a WUS response window; and perform an access procedure for the terminal and the second cell, wherein WUS-related information is transmitted from the second base station to a first base station corresponding to a first cell, and the WUS-related information includes at least one of carrier frequency information, WUS transmission occasion information, WUS format information, and WUS response window setting information of the second cell, and wherein the first cell corresponds to a cell type for access and synchronization, and the second cell corresponds to a cell type for data transmission and reception.

[0019] Through the embodiments of the present disclosure, by providing a definition of cells having different functions for energy saving of a base station in a mobile communication system in a 5G system, a WUS setting method for activating an on-demand cell, and a WUS carrier selection method, the base station can manage and save energy of the base station more efficiently by reducing the overhead of always having to periodically activate cells for common channels and signal transmission.

[0020] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0021] Figure 1 is a diagram illustrating the basic structure of the time-frequency domain, which is a wireless resource domain in a wireless communication system.

[0022] Figure 2 is a diagram illustrating a slot structure considered in a wireless communication system.

[0023] FIG. 3 is a diagram showing an example of a time domain mapping structure and beam sweeping operation of a synchronization signal.

[0024] FIG. 4 is a diagram illustrating a synchronization signal block considered in a wireless communication system.

[0025] FIG. 5 is a diagram illustrating an example of various transmissions of a synchronization signal block in a frequency band below 6 GHz considered in a communication system to which the present disclosure applies.

[0026] FIG. 6 is a diagram illustrating an example of transmission of a synchronization signal block in a frequency band of 6 GHz or higher considered in a wireless communication system to which the present disclosure applies.

[0027] FIG. 7 is a diagram illustrating an example of transmission of a synchronization signal block according to a subcarrier interval within 5 ms in a wireless communication system to which the present disclosure is applied.

[0028] FIG. 8 is a diagram illustrating an example of DMRS patterns (type 1 and type 2) used for communication between a base station and a terminal in a 5G system.

[0029] FIG. 9 is a diagram illustrating an example of channel estimation using DMRS received on one PUSCH in a time band of a 5G system to which the present disclosure is applied.

[0030] FIG. 10 is a diagram illustrating an example of a method for resetting SSB transmission through dynamic signaling according to an embodiment.

[0031] FIG. 11 is a diagram illustrating an example of a method for resetting BWP and BW through dynamic signaling according to an embodiment.

[0032] FIG. 12 is a diagram illustrating an example of a method for resetting DRX through dynamic signaling according to an embodiment.

[0033] FIG. 13 is a diagram illustrating an example of a DTx method for base station energy saving.

[0034] Fig. 14 is a diagram for explaining an example of the operation of a base station according to gNB WUS.

[0035] FIG. 15 is a diagram illustrating an example of a spatial domain (SD) adaptation method of a base station for energy saving according to an embodiment.

[0036] FIG. 16 is a diagram illustrating an example of a concept of cells having different functions for energy saving according to an embodiment.

[0037] FIG. 17 is a diagram illustrating an example of an on-demand cell selection method for energy saving of a base station according to an embodiment.

[0038] FIG. 18A is a diagram illustrating an example of a procedure for on-demand cell selection for energy saving of a base station according to an embodiment of the present disclosure.

[0039] FIG. 18b is a diagram illustrating an example of a procedure for on-demand cell selection for energy saving of a base station according to an embodiment of the present disclosure.

[0040] FIG. 19a is a diagram illustrating an example of a WUS transmission method for activating a data cell for energy saving of a base station according to an embodiment.

[0041] FIG. 19b is a diagram illustrating another example of a WUS transmission method for activating data cells for energy saving of a base station according to an embodiment.

[0042] FIG. 20 is a flowchart illustrating an example of an operation of a terminal that applies a cell selection method for energy saving of a base station in a 5G or 6G system to which the present disclosure is applied.

[0043] FIG. 21A is a flowchart illustrating an example of a base station operation serving a cell of cell type 1 that applies a cell selection method for energy saving of a base station in a 5G or 6G system to which the present disclosure applies.

[0044] FIG. 21b is a flowchart illustrating an example of a base station operation serving a cell of cell type 2 for energy saving of the base station in a 5G or 6G system to which the present disclosure applies.

[0045] FIG. 22 is a block diagram of a terminal according to one embodiment of the present disclosure.

[0046] FIG. 23 is a block diagram of a base station according to one embodiment of the present disclosure.

[0047] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings. In describing the embodiments of the present disclosure below, descriptions of technical details that are well-known in the technical field of the present disclosure and are not directly related to the present disclosure will be omitted. This is to avoid obscuring the gist of the present disclosure by omitting unnecessary explanations and to convey the gist more clearly.

[0048] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0049] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present disclosure is not limited to the embodiments described below and may be implemented in various different forms. These embodiments are provided only to make the present disclosure complete and to fully inform those skilled in the art of the present disclosure of the scope of the technical idea, and the present disclosure is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification. In addition, when describing the present disclosure, if a specific description of a related function or configuration is determined to unnecessarily obscure the gist of the present disclosure, a detailed description thereof will be omitted. In addition, the terms described below are terms defined in consideration of the functions of the present disclosure, and may vary depending on the intention or custom of the user or operator. Therefore, their definitions should be made based on the contents throughout the specification.

[0050] In the present disclosure below, A / B / C may be understood as at least one of A, B, and C.

[0051] Hereinafter, the base station is an entity that performs resource allocation of a terminal, and may be at least one of a gNode B, an eNode B, a Node B, a BS (Base Station), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (user equipment), an MS (mobile station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, downlink (DL) refers to a wireless transmission path of a signal transmitted from a base station to a terminal, and uplink (UL) refers to a wireless transmission path of a signal transmitted from a terminal to a base station. In addition, although an LTE or LTE-A system may be described below as an example, embodiments of the present disclosure may also be applied to other communication systems having a similar technical background or channel type. For example, the 5th generation mobile communication technology (5G, new radio, NR) developed after LTE-A may be included here, and 5G below may also be a concept that includes existing LTE, LTE-A, and other similar services. In addition, the present disclosure may be applied to other communication systems with some modifications within a scope that does not significantly deviate from the scope of the present disclosure, as judged by a person having skilled technical knowledge.

[0052] At this time, it will be understood that each block of the processing flow diagrams and combinations of the flow diagrams can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flow diagram block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flow diagram block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0053] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0054] The term '~ unit' used in this disclosure means a software or hardware component such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC), and the '~ unit' performs certain roles. However, the '~ unit' is not limited to software or hardware. The '~ unit' may be configured to be on an addressable storage medium and may be configured to play 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, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. Additionally, the components and '~parts' may be implemented to activate one or more CPUs within a device or secure multimedia card. In addition, in an embodiment, the '~parts' may include one or more processors.

[0055] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The method and device proposed in the embodiments of the present disclosure will be described as an example for improving uplink coverage when performing a random access procedure. However, the present disclosure is not limited to each embodiment, and it is also possible to utilize a combination of all or part of one or more embodiments proposed in the disclosure to a method for setting frequency resources corresponding to other channels. Therefore, the embodiments of the present disclosure may be applied with some modifications within a range that does not significantly deviate from the scope of the present disclosure at the discretion of a person having skilled technical knowledge.

[0056] Additionally, when describing the present disclosure, detailed descriptions of related functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined based on the functions of the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the contents of this specification.

[0057] Wireless communication systems are evolving from providing voice-oriented services in the early days to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as 3GPP's HSPA (high speed packet access), LTE (long term evolution or E-UTRA (evolved universal terrestrial radio access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2's HRPD (high rate packet data), UMB (ultra mobile broadband), and IEEE's 802.17e communication standards.

[0058] The LTE system, a representative example of a broadband wireless communication system, employs the orthogonal frequency division multiplexing (OFDM) method in the downlink (DL) and the single carrier frequency division multiple access (SC-FDMA) method in the uplink (UL). The uplink refers to a wireless link through which a terminal transmits data or control signals to a base station, and the downlink refers to a wireless link through which a base station transmits data or control signals to a terminal (UE). In addition, the aforementioned multiple access method typically allocates and operates time-frequency resources for transmitting data or control information to each user so that they do not overlap, that is, so that orthogonality is established, thereby distinguishing the data or control information of each user.

[0059] 5G communication systems, the successor to LTE, must support services that simultaneously satisfy diverse requirements, allowing them to freely reflect the diverse needs of users and service providers. Services being considered for 5G communication systems include enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable low-latency communication (URLLC).

[0060] eMBB aims to provide data transmission rates that are significantly higher than those supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB must be able to provide a peak data rate of 20 Gbps in the downlink and a peak data rate of 10 Gbps in the uplink from the perspective of a single base station. Furthermore, 5G communication systems must provide not only the peak data rate but also the increased user-perceived data rate for terminals. To meet these requirements, improvements in various transmission and reception technologies, including improved multi-input, multi-output (MIMO) transmission technology, may be required. Furthermore, while LTE systems transmit signals using a maximum transmission bandwidth of 20 MHz in the 2 GHz band, 5G communication systems can meet the data transmission rates required by 5G communication systems by using a wider frequency bandwidth than 20 MHz in the 3 to 6 GHz or higher frequency bands.

[0061] At the same time, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. To efficiently provide the Internet of Things, mMTC requires supporting a large number of terminals within a cell, improving terminal coverage, extending battery life, and reducing terminal costs. The Internet of Things provides communication functions by attaching various sensors and various devices, so a large number of terminals (e.g., 1,000,000 terminals / km) are required within a cell. 2) must be able to support. Furthermore, terminals supporting mMTC are likely to be located in shadow areas not covered by cells, such as basements of buildings, due to the nature of the service, requiring wider coverage than other services provided by 5G communication systems. Terminals supporting mMTC must be composed of low-cost terminals, and since it is difficult to frequently replace the terminal's battery, they require a very long battery life time, such as 10 to 16 years.

[0062] Finally, URLLC refers to a cellular-based wireless communication service used for a specific purpose (mission-critical). For example, services can be considered for remote control of robots or machinery, industrial automation, unmanaged aerial vehicles, remote health care, or emergency alerts. Therefore, the communication provided by URLLC must provide very low latency and very high reliability. For example, a service supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds and, at the same time, must have a 10 -5 The following packet error rate requirements must be met. Therefore, for services supporting URLLC, 5G systems must provide a smaller transmit time interval (TTI) than other services, while simultaneously allocating extensive resources in the frequency band to ensure communication link reliability.

[0063] The three services of the 5G communication system (hereinafter, "interoperable with 5G systems")—eMBB, URLLC, and mMTC—can be multiplexed and transmitted within a single system. To meet the different requirements of each service, different transmission and reception techniques and parameters can be used across the services.

[0064] The frame structure of the 5G system will be described in more detail below with reference to the drawings. For convenience of explanation, the wireless communication system to which the present disclosure applies will be described below using the configuration of a 5G system as an example. However, the embodiments of the present disclosure can be applied in the same or similar manner to systems beyond 5G or other communication systems to which the present disclosure applies.

[0065] FIG. 1 is a diagram illustrating the basic structure of a time-frequency domain, which is a wireless resource domain, in a wireless communication system to which the present disclosure is applied.

[0066] In Fig. 1, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The basic unit of resources in the time and frequency domains is a resource element (RE, 101), which can be defined as one orthogonal frequency division multiplexing (OFDM) symbol (or DFT-s-OFDM (discrete Fourier transform spread OFDM) symbol) (102) in the time axis and one subcarrier (subcarrier, 103) in the frequency axis. In the frequency domain, the number of subcarriers per resource block (RB) is represented by (For example, 12) consecutive REs can form one resource block (RB, 104). In addition, the number of symbols per subframe in the time domain is indicated. A number of consecutive OFDM symbols can constitute one subframe (subframe, 110).

[0067] FIG. 2 is a diagram illustrating a slot structure considered in a wireless communication system to which the present disclosure is applied.

[0068] FIG. 2 illustrates an example of a slot structure including a frame (200), a subframe (201), and a slot (202 or 203). One frame (200) can be defined as 10 ms. One subframe (201) can be defined as 1 ms, and thus one frame (200) can be composed of a total of 10 subframes (201). One slot (202, 203) can be defined as 14 OFDM symbols (i.e., the number of symbols per slot )=14). One subframe (201) may be composed of one or more slots (202 or 203), and the number of slots (202 or 203) per one subframe (201) may vary depending on μ (204 or 205), which is a setting value for the subcarrier space (SCS).

[0069] The slot structure is illustrated when μ=0 (204) and μ=1 (205) as the subcarrier spacing setting value. When μ=0 (204), one subframe (201) can be composed of one slot (202), and when μ=1 (205), one subframe (201) can be composed of two slots (including slot (203) for example). That is, depending on the setting value μ for the subcarrier spacing, the number of slots per subframe ( ) may vary, and accordingly the number of slots per frame ( ) may vary. For example, depending on the subcarrier spacing setting μ and can be defined as shown in Table 1 below.

[0070] μ 0141011142022144043148084141601651432032

[0071] In a 5G system, a synchronization signal block (SSB, which may be used interchangeably with an SS block or an SS / PBCH block) may be transmitted for initial connection of a terminal, and the synchronization signal block may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH).

[0072] In the initial access phase where a terminal connects to the system, the terminal can first acquire downlink time and frequency domain synchronization from a synchronization signal through cell search and acquire a cell ID. The synchronization signal may include PSS and SSS. In addition, the terminal can obtain transmission-related system information and basic parameter values, such as system bandwidth or related control information, by receiving a PBCH that transmits a master information block (MIB) from the base station. Based on this information, the terminal can perform decoding on the physical downlink control channel (PDCCH) and physical downlink shared channel (PDSCH) to acquire a system information block (SIB). Thereafter, the terminal can exchange identification-related information with the base station through a random access phase and go through registration and authentication phases to initially access the network. Additionally, the terminal can obtain cell-common transmission-related control information by receiving system information (or SIB) transmitted by the base station. The above cell common transmission and reception related control information may include random access related control information, paging related control information, common control information for various physical channels, etc.

[0073] A synchronization signal is a signal that serves as a reference for cell search, and subcarrier spacing can be applied to suit channel environments such as phase noise for each frequency band. In the case of a data channel or control channel, as described above, different subcarrier spacings can be applied depending on the service type in order to support various services.

[0074] FIG. 3 is a diagram showing an example of a time domain mapping structure and beam sweeping operation of a synchronization signal.

[0075] For the purpose of explanation, the following components can be defined:

[0076] - PSS: A signal that serves as a reference for DL ​​time / frequency synchronization and provides some cell ID information.

[0077] - SSS: It serves as a reference for DL ​​time / frequency synchronization and provides some remaining information such as cell ID. Additionally, it can serve as a reference signal for PBCH demodulation.

[0078] - PBCH: Provides MIB, which is essential system information required for transmission and reception of data channels and control channels of the terminal. The essential system information may include search space-related control information indicating radio resource mapping information of the 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 that serves as a timing reference.

[0079] - SS / PBCH block: An SS / PBCH block consists of N OFDM symbols and is a combination of PSS, SSS, PBCH, etc. In a system where beam sweeping technology is applied, the SS / PBCH block is the minimum unit to which beam sweeping is applied. In a 5G system, N can be 4. The 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). In addition, the L SS / PBCH blocks are periodically repeated in units of a predetermined period P. The period P can be notified to the terminal by the base station through signaling. If there is no separate signaling for the period P, the terminal applies a pre-agreed default value.

[0080] Referring to FIG. 3, FIG. 3 illustrates an example in which beam sweeping is applied to SS / PBCH block units over time. In the example of FIG. 3, terminal 1 (305) receives an SS / PBCH block using a beam radiated in the direction of #d0 (303) by beamforming applied to SS / PBCH block #0 at time t1 (301). Terminal 2 (306) receives an SS / PBCH block using a beam radiated in the direction of #d4 (304) by beamforming applied to SS / PBCH block #4 at time t2 (302). The terminal can obtain an optimal synchronization signal through a beam radiated from the base station in the direction where the terminal is located. For example, terminal 1 (305) may have difficulty in obtaining time / frequency synchronization and essential system information from an SS / PBCH block through a beam radiated in the direction of #d4, which is far from the location of terminal 1.

[0081] In addition to the initial connection procedure described above, the terminal may also receive SS / PBCH blocks to determine whether the radio link quality of the current cell is maintained at a certain level or higher. Furthermore, during a handover procedure in which the terminal moves from the current cell to a neighboring cell, the terminal may receive SS / PBCH blocks from the neighboring cell to determine the radio link quality of the neighboring cell and obtain time / frequency synchronization with the neighboring cell.

[0082] Below, the cell initial connection operation procedure of the 5G system will be described in more detail with reference to the drawings.

[0083] Synchronization signals serve as a reference for cell search and can be transmitted with subcarrier spacing appropriate for the channel environment (e.g., phase noise) for each frequency band. 5G base stations can transmit multiple synchronization signal blocks depending on the number of analog beams they intend to operate. For example, PSS and SSS can be mapped and transmitted across 12 RBs, and PBCH can be mapped and transmitted across 24 RBs. The following describes the structure by which synchronization signals and PBCHs are transmitted in a 5G communication system.

[0084] FIG. 4 is a diagram illustrating a synchronization signal block considered in a wireless communication system to which the present disclosure is applied.

[0085] According to FIG. 4, the synchronization signal block (SS block, 400) may include a PSS (401), an SSS (403), and a PBCH (402).

[0086] The synchronization signal block (400) can be mapped to four OFDM symbols (404) on the time axis. The PSS (401) and the SSS (403) can be transmitted in 12 RBs (405) on the frequency axis and in the first and third OFDM symbols on the time axis, respectively. In a 5G system, for example, a total of 1008 different cell IDs can be defined. Depending on the physical cell ID (PCI) of the cell, the PSS (401) can have three different values, and the SSS (403) can have 336 different values. The terminal can obtain one of (336 × 3 =) 1008 cell IDs by detecting the PSS (401) and the SSS (403) and combining them. This can be expressed by the following <Mathematical Formula 1>.

[0087] [Mathematical Formula 1]

[0088]

[0089] Here can be estimated from SSS(403) and can have a value between 0 and 335. can be estimated from PSS (401) and can have a value between 0 and 2. The terminal class Cell ID is a combination of The value can be estimated.

[0090] PBCH (402) can be transmitted in resources including 6 RBs (407, 408) on both sides, excluding 12 RBs (405) in the middle, while SSS (403) is transmitted in 24 RBs (406) in the frequency axis and in the 2nd to 4th OFDM symbols of the SS block in the time axis. PBCH (402) can include a PBCH payload and a PBCH DMRS (demodulation reference signal), and various system information called MIB can be transmitted in the PBCH payload. For example, MIB can include information as shown in Table 2 below.

[0091] MIB ::= SEQUENCE {systemFrameNumber BIT STRING (SIZE (6)),subCarrierSpacingCommon ENUMERATED {scs15or60, scs30or120},ssb-SubcarrierOffset INTEGER (0..15),dmrs-TypeA-Position ENUMERATED {pos2, pos3},pdcch-ConfigSIB1 PDCCH-ConfigSIB1,cellBarred ENUMERATED {barred, notBarred},intraFreqReselection ENUMERATED {allowed, notAllowed},spare BIT STRING (SIZE (1))}

[0092] - Synchronization signal block information: The frequency domain offset of the synchronization signal block can be indicated through the 4-bit ssb-SubcarrierOffset in the MIB. The index of the synchronization signal block including the PBCH can be indirectly obtained through decoding the PBCH DMRS and PBCH. In one embodiment, in a frequency band below 6 GHz, 3 bits obtained through decoding of PBCH DMRS may indicate a synchronization signal block index, and in a frequency band above 6 GHz, a total of 6 bits, including 3 bits obtained through decoding of PBCH DMRS and 3 bits obtained through PBCH decoding included in the PBCH payload, may indicate a synchronization signal block index including the PBCH. - PDCCH configuration information: The subcarrier spacing of the common downlink control channel may be indicated through 1 bit (subCarrierSpacingCommon) in the MIB, and time-frequency resource configuration information of CORESET (control resource set) and search space (SS) may be indicated through 8 bits (pdcch-ConfigSIB1).

[0093] - SFN: Within the MIB, 6 bits (systemFrameNumber) can be used to indicate a portion of the SFN. The 4 least significant bits (LSBs) of the SFN are included in the PBCH payload, so the terminal can indirectly obtain them through PBCH decoding.

[0094] - Timing information within a radio frame: The synchronization signal block index described above and 1 bit included in the PBCH payload are obtained through PBCH decoding, allowing the terminal to indirectly determine whether the synchronization signal block was transmitted in the first or second half frame of the radio frame.

[0095] Since the transmission bandwidths (12 RB (405)) of PSS (401) and SSS (403) and the transmission bandwidth (24 RB (406)) of PBCH (402) are different from each other, in the first OFDM symbol in which PSS (401) is transmitted within the transmission bandwidth of PBCH (402), 6 RBs (407, 408) on both sides exist except for the 12 RBs in the middle in which PSS (401) is transmitted, and the above areas can be used to transmit other signals or can be empty.

[0096] Synchronization signal blocks can be transmitted using the same analog beam. For example, PSS (401), SSS (403), and PBCH (402) can all be transmitted using the same beam. Since analog beams have the characteristic that they cannot be applied differently in the frequency axis, the same analog beam can be applied to all frequency axis RBs within a specific OFDM symbol to which a specific analog beam is applied. For example, all four OFDM symbols in which PSS (401), SSS (403), and PBCH (402) are transmitted can be transmitted using the same analog beam.

[0097] FIG. 5 is a diagram illustrating an example of various transmissions of a synchronization signal block in a frequency band below 6 GHz considered in a communication system to which the present disclosure applies.

[0098] Referring to FIG. 5, in a 5G communication system, a 15 kHz subcarrier spacing (SCS) 520 and a 30 kHz subcarrier spacing (530, 440) may be used for transmission of a synchronization signal block in a frequency band below 6 GHz. In the 15 kHz subcarrier spacing (520), there may be one transmission case (e.g., case #1 (501)) for the synchronization signal block, and in the 30 kHz subcarrier spacing (530, 540), there may be two transmission cases (e.g., case #2 (402) and case #3 (503)) for the synchronization signal block.

[0099] In case #1 (501) at the subcarrier spacing of 15 kHz (520) in FIG. 5, a maximum of two synchronization signal blocks can be transmitted within 1 ms (504) (or equivalent to 1 slot length when 1 slot consists of 14 OFDM symbols). In the example of FIG. 4, synchronization signal block #0 (507) and synchronization signal block #1 (508) are illustrated. For example, synchronization signal block #0 (507) can be mapped to 4 consecutive symbols from the 3rd OFDM symbol, and synchronization signal block #1 (508) can be mapped to 4 consecutive symbols from the 9th OFDM symbol.

[0100] Different analog beams may be applied to the synchronization signal block #0 (507) and synchronization signal block #1 (508). The same beam may be applied to all 3rd to 6th OFDM symbols to which synchronization signal block #0 (507) is mapped, and the same beam may be applied to all 9th ​​to 12th OFDM symbols to which synchronization signal block #1 (508) is mapped. In the 7th, 8th, 13th, and 14th OFDM symbols to which synchronization signal blocks are not mapped, the analog beam may be freely determined at the discretion of the base station as to which beam to use.

[0101] In case #2 (502) at the subcarrier spacing of 30 kHz (530) in FIG. 5, a maximum of two synchronization signal blocks can be transmitted within 0.5 ms (505) (or 1 slot length when 1 slot consists of 14 OFDM symbols), and accordingly, a maximum of four synchronization signal blocks can be transmitted within 1 ms (or 2 slot lengths when 1 slot consists of 14 OFDM symbols). In the example of FIG. 4, a case is illustrated where synchronization signal block #0 (509), synchronization signal block #1 (510), synchronization signal block #2 (511), and synchronization signal block #3 (512) are transmitted within 1 ms (i.e., two slots) of time. Synchronization signal block #0 (509) and synchronization signal block #1 (510) can be mapped from the 5th OFDM symbol and the 9th OFDM symbol of the first slot, respectively, and synchronization signal block #2 (511) and synchronization signal block #3 (512) can be mapped from the 3rd OFDM symbol and the 7th OFDM symbol of the second slot, respectively.

[0102] Different analog beams may be applied to the synchronization signal block #0 (509), synchronization signal block #1 (510), synchronization signal block #2 (511), and synchronization signal block #3 (512), respectively. In addition, the same analog beam may be applied to the 5th to 8th OFDM symbols of the first slot in which synchronization signal block #0 (509) is transmitted, the 9th to 12th OFDM symbols of the first slot in which synchronization signal block #1 (510) is transmitted, the 3rd to 6th symbols of the second slot in which synchronization signal block #2 (511) is transmitted, and the 7th to 10th symbols of the second slot in which synchronization signal block #3 (512) is transmitted. In OFDM symbols in which synchronization signal blocks are not mapped, the analog beam may be freely determined at the discretion of the base station as to which beam to use.

[0103] In case #3 (503) at subcarrier spacing of 30 kHz (540) in FIG. 5, a maximum of two synchronization signal blocks can be transmitted within 0.5 ms (506) (or 1 slot length when 1 slot consists of 14 OFDM symbols), and accordingly, a maximum of four synchronization signal blocks can be transmitted within 1 ms (or 2 slot lengths when 1 slot consists of 14 OFDM symbols). In the example of FIG. 4, synchronization signal block #0 (513), synchronization signal block #1 (514), synchronization signal block #2 (515), and synchronization signal block #3 (516) are illustrated as being transmitted within 1 ms (i.e., two slots) of time. Synchronization signal block #0 (513) and synchronization signal block #1 (514) can be mapped from the 3rd OFDM symbol and the 9th OFDM symbol of the first slot, respectively, and synchronization signal block #2 (515) and synchronization signal block #3 (516) can be mapped from the 3rd OFDM symbol and the 9th OFDM symbol of the second slot, respectively.

[0104] Different analog beams may be used for the above synchronization signal block #0 (513), synchronization signal block #1 (514), synchronization signal block #2 (515), and synchronization signal block #3 (516), respectively. As described in the above examples, the same analog beam may be used in all four OFDM symbols in which each synchronization signal block is transmitted, and which beam to use in OFDM symbols to which the synchronization signal block is not mapped may be freely determined at the discretion of the base station.

[0105] FIG. 6 is a diagram illustrating an example of transmission of a synchronization signal block in a frequency band of 6 GHz or higher considered in a wireless communication system to which the present disclosure applies.

[0106] In a 5G communication system, in a frequency band of 6 GHz or higher, a subcarrier spacing of 120 kHz (630) as in the example of Case #4 (610) and a subcarrier spacing of 240 kHz (640) as in the example of Case #5 (620) may be used for transmission of synchronization signal blocks.

[0107] In case #4 (610) with a subcarrier spacing of 120 kHz (630), up to four synchronization signal blocks can be transmitted within a time period of 0.25 ms (601) (or equivalent to two slot lengths when one slot consists of 14 OFDM symbols). In the example of Fig. 6, synchronization signal block #0 (603), synchronization signal block #1 (604), synchronization signal block #2 (605), and synchronization signal block #3 (606) are illustrated as being transmitted within 0.25 ms (i.e., two slots). Synchronization signal block #0 (603) and synchronization signal block #1 (604) can be mapped to 4 consecutive symbols starting from the 5th OFDM symbol of the first slot, and to 4 consecutive symbols starting from the 9th OFDM symbol, respectively, and synchronization signal block #2 (605) and synchronization signal block #3 (606) can be mapped to 4 consecutive symbols starting from the 3rd OFDM symbol of the second slot, and to 4 consecutive symbols starting from the 7th OFDM symbol, respectively.

[0108] As described in the above embodiment, different analog beams may be used for synchronization signal block #0 (603), synchronization signal block #1 (604), synchronization signal block #2 (605), and synchronization signal block #3 (606), respectively. In addition, the same analog beam may be used in all four OFDM symbols in which each synchronization signal block is transmitted, and in OFDM symbols to which the synchronization signal block is not mapped, the beam to be used may be freely determined at the discretion of the base station.

[0109] In case #5 (620) at subcarrier spacing of 240 kHz (640), up to 8 synchronization signal blocks can be transmitted within 0.25 ms (602) (or 4 slot length when 1 slot consists of 14 OFDM symbols). In the example of Fig. 6, synchronization signal block #0 (607), synchronization signal block #1 (608), synchronization signal block #2 (609), synchronization signal block #3 (610), synchronization signal block #4 (611), synchronization signal block #5 (612), synchronization signal block #6 (613), and synchronization signal block #7 (614) are illustrated as being transmitted within 0.25 ms (i.e. 4 slots).

[0110] Synchronization signal block #0 (607) and synchronization signal block #1 (608) can be mapped to 4 consecutive symbols from the 9th OFDM symbol of the first slot, and 4 consecutive symbols from the 13th OFDM symbol, respectively; synchronization signal block #2 (609) and synchronization signal block #3 (610) can be mapped to 4 consecutive symbols from the 3rd OFDM symbol of the second slot, and 4 consecutive symbols from the 7th OFDM symbol, respectively; synchronization signal block #4 (611), synchronization signal block #5 (612), and synchronization signal block #6 (613) can be mapped to 4 consecutive symbols from the 5th OFDM symbol of the third slot, and 4 consecutive symbols from the 9th OFDM symbol, and 4 consecutive symbols from the 13th OFDM symbol, respectively; synchronization signal block #7 (614) can be mapped to 4 consecutive symbols from the 4th slot, and 4 consecutive symbols from the 9th OFDM symbol, respectively; It can be mapped to four consecutive symbols starting from the third OFDM symbol.

[0111] As described in the above embodiment, different analog beams may be used for synchronization signal block #0 (607), synchronization signal block #1 (608), synchronization signal block #2 (609), synchronization signal block #3 (610), synchronization signal block #4 (611), synchronization signal block #5 (612), synchronization signal block #6 (613), and synchronization signal block #7 (614), respectively. In addition, the same analog beam may be used in all four OFDM symbols in which each synchronization signal block is transmitted, and in OFDM symbols to which the synchronization signal block is not mapped, which beam to be used may be freely determined at the discretion of the base station.

[0112] FIG. 7 is a diagram illustrating an example of transmission of a synchronization signal block according to a subcarrier interval within 5 ms in a wireless communication system to which the present disclosure is applied.

[0113] Referring to FIG. 7, in a 5G communication system, a synchronization signal block may be periodically transmitted in units of, for example, a time interval (710) of 5 ms (corresponding to 5 subframes or half frames).

[0114] In the frequency band below 3 GHz, up to 4 synchronization signal blocks can be transmitted within a 5 ms (710) period. In the frequency band above 3 GHz and below 6 GHz, up to 8 synchronization signal blocks can be transmitted. In the frequency band above 6 GHz, up to 64 synchronization signal blocks can be transmitted. As described above, subcarrier spacings of 15 kHz and 30 kHz can be used in the frequency below 6 GHz.

[0115] In the example of FIG. 7, in case #1 (501) of FIG. 5, which consists of one slot and has a subcarrier spacing of 15 kHz, synchronization signal blocks can be mapped to the first and second slots in a frequency band of 3 GHz or less, so that up to 4 (721) can be transmitted, and in the frequency band of more than 3 GHz and less than 6 GHz, synchronization signal blocks can be mapped to the first, second, third, and fourth slots, so that up to 8 (722) can be transmitted. In case #2 (502) or case #3 (503) with a subcarrier spacing of 30 kHz and consisting of two slots of FIG. 5, synchronization signal blocks can be mapped starting from the first slot in a frequency band of 3 GHz or less, so that up to 4 (731, 741) can be transmitted, and in a frequency band exceeding 3 GHz and below 6 GHz, synchronization signal blocks can be mapped starting from the first and third slots, so that up to 8 (732, 742) can be transmitted.

[0116] Subcarrier spacings of 120 kHz and 240 kHz can be used in frequencies exceeding 6 GHz. In the example of Fig. 6, in case #4 (610) with subcarrier spacing of 120 kHz consisting of two slots of Fig. 6, synchronization signal blocks in the frequency band exceeding 6 GHz can be mapped starting from the 1st, 3rd, 5th, 7th, 11th, 13th, 15th, 17th, 21st, 23rd, 25th, 27th, 31st, 33rd, 35th, and 37th slots, so that up to 64 (751) can be transmitted. In the example of FIG. 7, in case #5 (620) of FIG. 6, which consists of 4 slots and has a subcarrier spacing of 240 kHz, synchronization signal blocks in a frequency band exceeding 6 GHz can be mapped starting from the 1st, 5th, 9th, 13th, 21st, 25th, 29th, and 33rd slots, so that up to 64 (761) can be transmitted.

[0117] The terminal can decode the PDCCH and PDSCH based on the system information included in the received MIB and then acquire the SIB. The SIB may include at least one of uplink cell bandwidth-related information, random access parameters, paging parameters, or parameters related to uplink power control.

[0118] Typically, a terminal can establish a wireless link with a network through a random access procedure based on synchronization with the network and system information acquired during the cell search process. Random access can be either contention-based or contention-free. When a terminal performs cell selection and reselection during the initial cell access phase, for example, contention-based random access can be used to transition from the RRC_IDLE state to the RRC_CONNECTED state. Contention-free random access can be used to reestablish uplink synchronization when downlink data arrives, in the case of a handover, or for positioning. Table 3 below illustrates the conditions (events) that trigger the random access procedure in a 5G system.

[0119] - Initial access from RRC_IDLE;- RRC Connection Re-establishment procedure;- DL or UL data arrival during RRC_CONNECTED when UL synchronization status is "non-synchronised";- UL data arrival during RRC_CONNECTED when there are no PUCCH resources for SR available;- SR failure;- Request by RRC upon synchronous reconfiguration (eg handover);- RRC Connection Resume procedure from RRC_INACTIVE;- To establish time alignment for a secondary TAG;- Request for Other SI;- Beam failure recovery;- Consistent UL LBT failure on SpCell.

[0120] Below, a method for setting a measurement time for RRM (radio resource management) based on a synchronization signal block of a 5G wireless communication system is described.

[0121] The terminal receives MeasObjectNR from MeasObjectToAddModList via upper-layer signaling to configure SSB-based intra / inter-frequency measurements and CSI-RS-based intra / inter-frequency measurements. For example, MeasObjectNR can be configured as shown in Table 4 below.

[0122] MeasObjectNR ::= SEQUENCE {ssbFrequency ARFCN-ValueNR OPTIONAL, -- Cond SSBorAssociatedSSBssbSubcarrierSpacing SubcarrierSpacing OPTIONAL, -- Cond SSBorAssociatedSSBsmtc1 SSB-MTC OPTIONAL, -- Cond SSBorAssociatedSSBsmtc2 SSB-MTC2 OPTIONAL, -- Cond IntraFreqConnectedrefFreqCSI-RS ARFCN-ValueNR OPTIONAL, -- Cond CSI-RSreferenceSignalConfig ReferenceSignalConfig,absThreshSS-BlocksConsolidation ThresholdNR OPTIONAL, -- Need RabsThreshCSI-RS-Consolidation ThresholdNR OPTIONAL, -- Need RnrofSS-BlocksToAverage INTEGER (2..maxNrofSS-BlocksToAverage) OPTIONAL, -- Need RnrofCSI-RS-ResourcesToAverage INTEGER (2..maxNrofCSI-RS-ResourcesToAverage) OPTIONAL, -- Need RquantityConfigIndex INTEGER (1..maxNrofQuantityConfig),offsetMO Q-OffsetRangeList,cellsToRemoveList PCI-List OPTIONAL, -- Need NcellsToAddModList CellsToAddModList OPTIONAL, -- Need NblackCellsToRemoveList PCI-RangeIndexList OPTIONAL, -- Need NblackCellsToAddModList SEQUENCE (SIZE (1..maxNrofPCI-Ranges)) OF PCI-RangeElement OPTIONAL, -- Need NwhiteCellsToRemoveList PCI-RangeIndexList OPTIONAL, -- Need NwhiteCellsToAddModList SEQUENCE (SIZE (1..maxNrofPCI-Ranges)) OF PCI-RangeElement OPTIONAL, -- Need N...,[[freqBandIndicatorNR FreqBandIndicatorNR OPTIONAL, -- Need RmeasCycleSCell ENUMERATED {sf160, sf256, sf320, sf512, sf640, sf1024, sf1280} OPTIONAL -- Need R]],[[smtc3list-r16 SSB-MTC3List-r16 OPTIONAL, -- Need Rrmtc-Config-r16 SetupRelease {RMTC-Config-r16} OPTIONAL, -- Need Mt312-r16 SetupRelease { T312-r16} OPTIONAL -- Need M]]}.

[0123] -ssbFrequency: You can set the frequency of the synchronization signal related to MeasObjectNR. -ssbSubcarrierSpacing: Sets the subcarrier spacing of SSB. FR (frequency range) 1 can only apply to 15 kHz or 30 kHz, and FR2 can only apply to 120 kHz or 240 kHz.

[0124] -smtc1: Indicates SMTC (SS / PBCH block measurement timing configuration), which sets the primary measurement timing configuration and allows you to set the timing offset and duration for SSB.

[0125] -smtc2:You can set the secondary measurement timing configuration for the SSB associated with the MeasObjectNR having the PCI listed in pci-List.

[0126] In addition to this, SMTC can be configured to the UE through other higher layer signaling, for example, SIB2 for intra-frequency, inter-frequency and inter-RAT (radio access technology) cell reselection, or reconfigurationWithSync for NR PSCell (primary secondary cell) change and NR PCell (primary cell) change, and also through SCellConfig for NR SCell addition.

[0127] For SSB measurement, the terminal can set the first SMTC according to periodictiyAndOffset (providing periodicity and offset) through smtc1 set through upper layer signaling. In one embodiment, the first subframe of each SMTC occasion can start in the subframe of the SFN and SpCell that satisfy the conditions in Table 5 below.

[0128] SFN modT= (FLOOR (Offset / 10));if thePeriodicityis larger thansf5:subframe =Offsetmod 10;else:subframe =Offsetor (Offset+5);withT= CEIL(Periodicity / 10).

[0129] If smtc2 is configured, the UE can configure additional SMTCs according to the configured smtc2 periodicity and the offset and interval of smtc1 for the cells indicated by the pci-List value of smtc2 in the same MeasObjectNR. In addition, the UE can be configured with smtc and measure SSB through smtc2-LP (with long periodicity) and smtc3list for IAB-MT (integrated access and backhaul - mobile termination) for the same frequency (e.g., frequency for intra-frequency cell reselection) or different frequencies (e.g., frequencies for inter-frequency cell reselection). In one embodiment, the UE may not consider SSB transmitted in subframes other than SMTC occasions for SSB-based RRM measurements at the configured ssbFrequency. The base station can use various multi-TRP (transmit / receive point) operation schemes depending on the serving cell configuration and PCI configuration. Among them, when two TRPs located at a physically distant distance have different PCIs, there may be two methods for operating the two TRPs.

[0130] [Operation Method 1]

[0131] Two TRPs with different PCIs can operate with two serving cell configurations.

[0132] The base station can configure channels and signals transmitted from different TRPs within different serving cell configurations through [Operation Method 1]. That is, each TRP has an independent serving cell configuration, and the frequency band values ​​FrequencyInfoDLs indicated by DownlinkConfigCommon within each serving cell configuration can indicate at least some overlapping bands. Since the above multiple TRPs operate based on multiple ServCellIndexes (e.g., ServCellIndex #1 and ServCellIndex #2), it is possible for each TRP to use a separate PCI. That is, the base station can allocate one PCI per ServCellIndex.

[0133] In this case, if multiple SSBs are transmitted from TRP 1 and TRP 2, and the SSBs have different PCIs (e.g., PCI #1 and PCI #2), the base station can appropriately select the value of ServCellIndex indicated by the cell parameter in QCL-Info to map the PCI suitable for each TRP and designate the SSB transmitted from either TRP 1 or TRP 2 as the source reference RS of the QCL configuration information. However, this configuration applies one serving cell configuration that can be used for carrier aggregation (CA) of the terminal to multiple TRPs, which has the problem of limiting the degree of freedom of CA configuration or increasing the signaling burden.

[0134] [Operation Method 2]

[0135] Two TRPs with different PCIs can operate with one serving cell configuration.

[0136] The base station can configure channels and signals transmitted in different TRPs through a single serving cell configuration through [Operation Method 2]. Since the terminal operates based on a single ServCellIndex (e.g., ServCellIndex #1), it is impossible for it to recognize the PCI (e.g., PCI #2) allocated to the second TRP. [Operation Method 2] may have greater freedom in CA configuration compared to the above-described [Operation Method 1], but if multiple SSBs are transmitted in TRP 1 and TRP 2, the SSBs may have different PCIs (e.g., PCI #1 and PCI #2), and the base station may not be able to map the PCI (e.g., PCI #2) of the second TRP through the ServCellIndex indicated by the cell parameter in the QCL-Info. The base station may only be able to designate the SSB transmitted in TRP 1 as the source reference RS of the QCL configuration information, and may not be able to designate the SSB transmitted in TRP 2.

[0137] As described above, [Operation Method 1] can perform multi-TRP operation for two TRPs with different PCIs through additional serving cell configuration without additional standard support, but [Operation Method 2] can operate based on the following additional terminal capability report and base station configuration information.

[0138] Terminal capability reporting for [Operation Method 2]

[0139] - The terminal can report to the base station via upper layer signaling that it can configure additional PCIs other than the PCI of the serving cell through the terminal capability. The terminal capability may include two independent numbers, X1 and X2, or each X1 and X2 may be reported as an independent terminal capability.

[0140] - X1 means the maximum number of additional PCIs that can be set for the terminal, and the PCI may be different from the PCI of the serving cell. In this case, the time domain position and periodicity of the SSB corresponding to the additional PCI may be the same as the SSB of the serving cell.

[0141] - X2 means the maximum number of additional PCIs that can be set for the terminal, and the PCI at this time may be different from the PCI of the serving cell, and the time domain location and period of the SSB corresponding to the additional PCI at this time may mean different from the SSB corresponding to the PCI reported as X1.

[0142] - By definition, the PCIs corresponding to the values ​​reported by X1 and X2 cannot be set simultaneously.

[0143] - The values ​​reported as X1 and X2 through the terminal capability report can each have an integer value from 0 to 7.

[0144] - The values ​​reported as X1 and X2 may have different values ​​reported in FR1 and FR2.

[0145] Regarding upper layer signaling settings for [Operation Method 2]

[0146] - The terminal may receive from the base station the upper layer signaling SSB-MTCAdditionalPCI-r17 based on the terminal capability report described above, and the upper layer signaling may include at least a plurality of additional PCIs having different values ​​from the serving cell, SSB transmit power corresponding to each additional PCI, and ssb-PositionInBurst corresponding to each additional PCI, and the maximum number of additional PCIs that can be set may be 7.

[0147] - The terminal can be assumed to have the same center frequency, subcarrier spacing, and subframe number offset as the SSB of the serving cell, as an assumption for the SSB corresponding to the additional PCI of a different value from the serving cell.

[0148] - The terminal can assume that the reference RS (e.g., SSB or CSI-RS) corresponding to the PCI of the serving cell is always connected to the activated TCI state, and in case of an additionally configured PCI with a different value from the serving cell, when there are one or more PCIs, it can assume that only one PCI among those PCIs is connected to the activated TCI state.

[0149] - If a terminal is configured with two different coresetPoolIndexes, and a reference RS corresponding to a serving cell PCI is connected to one or more activated TCI states, and a reference RS corresponding to an additionally configured PCI having a different value from the serving cell is connected to one or more activated TCI states, the terminal can expect that the activated TCI state(s) connected to the serving cell PCI will be connected to one of the two coresetPoolIndexes, and the activated TCI state(s) connected to the additionally configured PCI having a different value from the serving cell will be connected to the remaining one coresetPoolIndex.

[0150] The terminal capability report and the upper layer signaling of the base station for the above-described [Operation Method 2] can set an additional PCI with a different value from the PCI of the serving cell. If the above setting does not exist, the SSB corresponding to the additional PCI with a different value from the PCI of the serving cell that cannot be designated as the source reference RS can be used for the purpose of designating the source reference RS of the QCL configuration information. In addition, unlike the SSB that can be set for purposes such as RRM, mobility management, or handover, such as the configuration information for the SSB that can be set in the upper layer signaling smtc1 and smtc2, it can be used to serve as a QCL source RS to support multiple TRP operations with different PCIs.

[0151] Next, we will specifically explain DMRS, one of the reference signals in the 5G system.

[0152] A DMRS can be composed of multiple DMRS ports, and each port maintains orthogonality to avoid interference with each other by using code division multiplexing (CDM) or frequency division multiplexing (FDM). However, the term for DMRS can be expressed by different terms depending on the user's intention and the purpose of using the reference signal. The term DMRS is only provided as a specific example to easily explain the technical content of the present disclosure and to help understand the present disclosure, and is not intended to limit the scope of the present disclosure. In other words, it is obvious to a person skilled in the art to which the present disclosure pertains that the technical idea of ​​the present disclosure can be implemented for any reference signal.

[0153] Figure 8 is a diagram illustrating examples of DMRS patterns (type 1 and type 2) used for communication between a base station and a terminal in a 5G system. Two DMRS patterns can be supported in a 5G system, and two DMRS patterns are illustrated in Figure 8.

[0154] Referring to FIG. 8, reference numbers 801 and 802 correspond to DMRS type 1, where reference number 801 represents a 1-symbol pattern and reference number 802 represents a 2-symbol pattern. DMRS type 1 (801, 802) is a DMRS pattern of a comb 2 structure and can be composed of two CDM groups, and different CDM groups can be FDMed.

[0155] In the 1 symbol pattern (801), frequency-based CDM can be applied to the same CDM group to distinguish two DMRS ports, and thus a total of four orthogonal DMRS ports can be configured. The 1 symbol pattern (801) can include a DMRS port ID mapped to each CDM group (the DMRS port ID for downlink can be indicated by the illustrated number + 1000). In the 2 symbol pattern (802), time / frequency-based CDM can be applied to the same CDM group to distinguish four DMRS ports, and thus a total of eight orthogonal DMRS ports can be configured. The 2 symbol pattern (802) can include a DMRS port ID mapped to each CDM group (the DMRS port ID for downlink can be indicated by the illustrated number + 1000).

[0156] DMRS type 2 (803, 804) is a DMRS pattern in which FD-OCC (frequency domain orthogonal cover codes) are applied to frequency-adjacent subcarriers. It can be composed of three CDM groups, and different CDM groups can be FDMed.

[0157] In the 1 symbol pattern (803), frequency-based CDM may be applied to the same CDM group, so that two DMRS ports may be distinguished, and thus a total of six orthogonal DMRS ports may be configured. The 1 symbol pattern (803) may include a DMRS port ID mapped to each CDM group (the DMRS port ID for downlink may be indicated by the illustrated number + 1000). In the 2 symbol pattern (704), time / frequency-based CDM may be applied to the same CDM group, so that four DMRS ports may be distinguished, and thus a total of twelve orthogonal DMRS ports may be configured. The 2 symbol pattern (804) may include a DMRS port ID mapped to each CDM group (the DMRS port ID for downlink may be indicated by the illustrated number + 1000).

[0158] As described above, in the NR system, two different DMRS patterns (e.g., DMRS patterns (801, 802) or DMRS patterns (803, 804)) can be configured, and it can also be configured whether each DMRS pattern is a one-symbol pattern (801 or 803) or two adjacent symbol patterns (802 or 804). In addition, in the NR system, not only the DMRS port number is scheduled, but also the number of CDM groups scheduled together for PDSCH rate matching can be configured and signaled. In addition, in the case of CP-OFDM (cyclic prefix based orthogonal frequency division multiplex), both of the above-described DMRS patterns can be supported in the DL and UL, and in the case of DFT-S-OFDM (discrete Fourier transform spread OFDM), only DMRS type 1 among the above-described DMRS patterns can be supported in the UL.

[0159] Additionally, support may be provided for configuring additional DMRS. Front-loaded DMRS refers to the first DMRS transmitted and received in the frontmost symbol in the time domain among DMRSs, and additional DMRS refers to DMRS transmitted and received in symbols later than the front-loaded DMRS in the time domain. In an NR system, the number of additional DMRSs can be set from a minimum of 0 to a maximum of 3. Additionally, when an additional DMRS is configured, the same pattern as the front-loaded DMRS may be assumed. In one embodiment, when information about whether the DMRS pattern type described above is type 1 or type 2, information about whether the DMRS pattern is a 1-symbol pattern or an adjacent 2-symbol pattern, and information about the number of CDM groups used with the DMRS port are indicated for the front-loaded DMRS, when an additional DMRS is additionally configured, it may be assumed that the additional DMRS has the same DMRS information as the front-loaded DMRS.

[0160] In one embodiment, the downlink DMRS settings described above can be set via RRC signaling as shown in Table 6 below.

[0161] DMRS-DownlinkConfig ::= SEQUENCE {dmrs-Type ENUMERATED {type2} OPTIONAL, -- Need Sdmrs-AdditionalPosition ENUMERATED {pos0, pos1, pos3} OPTIONAL, -- Need SmaxLength ENUMERATED {len2} OPTIONAL, -- Need SscramblingID0 INTEGER (0..65535) OPTIONAL, -- Need SscramblingID1 INTEGER (0..65535) OPTIONAL, -- Need SphaseTrackingRS SetupRelease {PTRS-DownlinkConfig} OPTIONAL, -- Need M...}

[0162] Here, dmrs-Type can set the DMRS type, dmrs-AdditionalPosition can set additional DMRS OFDM symbols, maxLength can set a 1-symbol DMRS pattern or a 2-symbol DMRS pattern, scramblingID0 and scramblingID1 can set scrambling IDs, and phaseTrackingRS can set a PTRS (phase tracking reference signal). In addition, the uplink DMRS settings described above can be set through RRC signaling as shown in Table 7 below.

[0163] DMRS-UplinkConfig ::= SEQUENCE {dmrs-Type ENUMERATED {type2} OPTIONAL, -- Need Sdmrs-AdditionalPosition ENUMERATED {pos0, pos1, pos3} OPTIONAL, -- Need RphaseTrackingRS SetupRelease { PTRS-UplinkConfig} OPTIONAL, -- Need MmaxLength ENUMERATED {len2} OPTIONAL, -- Need StransformPrecodingDisabled SEQUENCE {scramblingID0 INTEGER (0..65535) OPTIONAL, -- Need SscramblingID1 INTEGER (0..65535) OPTIONAL, -- Need S...} OPTIONAL, -- Need RtransformPrecodingEnabled SEQUENCE {nPUSCH-Identity INTEGER (0..1007) OPTIONAL, -- Need SsequenceGroupHopping ENUMERATED {disabled} OPTIONAL, -- Need SsequenceHopping ENUMERATED {enabled} OPTIONAL, -- Need S...} OPTIONAL, -- Need R...}

[0164] Here, dmrs-Type can set the DMRS type, dmrs-AdditionalPosition (can set additional DMRS OFDM symbols), phaseTrackingRS can set PTRS, maxLength can set a 1-symbol DMRS pattern or a 2-symbol DMRS pattern, scramblingID0 and scramblingID1 can set scrambling ID0s, nPUSCH-Identity can set a cell ID for DFT-s-OFDM, sequenceGroupHopping can disable sequence group hopping, and sequenceHopping can enable sequence hopping.

[0165] FIG. 9 is a diagram illustrating an example of channel estimation using DMRS received from one PUSCH in a time band of a 5G system.

[0166] Referring to Fig. 9, when performing channel estimation for data decoding using DMRS, channel estimation can be performed within a PRG (precoding resource block group), which is a bundling unit, using PRB bundling (physical resource blocks bundling) linked to the system band in the frequency band. In addition, in the time unit, the channel is estimated by assuming that only DMRS received on one PUSCH has the same precoding.

[0167] Below, we describe a time domain resource allocation (TDRA) method for data channels in a 5G communication system. A base station can configure a time domain resource allocation information table for a downlink data channel (PDSCH) and an uplink data channel (PUSCH) to a terminal via higher-layer signaling (e.g., RRC signaling).

[0168] The base station may set a table with at most maxNrofDL-Allocations=17 entries for PDSCH, and may set a table with at most maxNrofUL-Allocations=17 entries for PUSCH. The time domain resource allocation information may include, for example, at least one of PDCCH-to-PDSCH slot timing (corresponding to a slot-unit time interval between a time point when a PDCCH is received and a time point when a PDSCH scheduled by the received PDCCH is transmitted, denoted as K0) or PDCCH-to-PUSCH slot timing (corresponding to a slot-unit time interval between a time point when a PDCCH is received and a time point when a PUSCH scheduled by the received PDCCH is transmitted, denoted as K2), information on the position and length of a start symbol on which a PDSCH or PUSCH is scheduled within a slot, and a mapping type of a PDSCH or PUSCH.

[0169] In one embodiment, time domain resource allocation information for PDSCH can be set to a terminal through RRC signaling as shown in Table 8 below.

[0170] PDSCH-TimeDomainResourceAllocationListinformation elementPDSCH-TimeDomainResourceAllocationList ::= SEQUENCE (SIZE(1..maxNrofDL-Allocations)) OF PDSCH-TimeDomainResourceAllocationPDSCH-TimeDomainResourceAllocation ::= SEQUENCE {k0 INTEGER(0..32) OPTIONAL, -- Need SmappingType ENUMERATED {typeA, typeB},startSymbolAndLength INTEGER (0..127)repetitionNumber ENUMERATED {n2, n3, n4, n5, n6, n7, n8, n16} OPTIONAL, -- Cond Formats1-0and1-1}

[0171] Here, k0 represents the PDCCH-to-PDSCH timing (i.e., the slot offset between the DCI and the scheduled PDSCH) in slot units, mappingType represents the PDSCH mapping type, startSymbolAndLength represents the start symbol and length of the PDSCH, and repetitionNumber may represent the number of PDSCH transmission occasions according to the slot-based repetition method. In one embodiment, time domain resource allocation information for PUSCH may be set to the terminal through RRC signaling as shown in Table 9 below.

[0172] PUSCH-TimeDomainResourceAllocationinformation elementPUSCH-TimeDomainResourceAllocationList ::= SEQUENCE (SIZE(1..maxNrofUL-Allocations)) OF PUSCH-TimeDomainResourceAllocationPUSCH-TimeDomainResourceAllocation ::= SEQUENCE {k2 INTEGER(0..32) OPTIONAL, -- Need SmappingType ENUMERATED {typeA, typeB},startSymbolAndLength INTEGER (0..127)}PUSCH-Allocation-r16 ::= SEQUENCE {mappingType-r16 ENUMERATED {typeA, typeB} OPTIONAL, -- Cond NotFormat01-02-Or-TypeAstartSymbolAndLength-r16 INTEGER (0..127) OPTIONAL, -- Cond NotFormat01-02-Or-TypeAstartSymbol-r16 INTEGER (0..13) OPTIONAL, -- Cond RepTypeBlength-r16 INTEGER (1..14) OPTIONAL, -- Cond RepTypeBnumberOfRepetitions-r16 ENUMERATED {n1, n2, n3, n4, n7, n8, n12, n16} OPTIONAL, -- Cond Format01-02...}

[0173] Here, k2 represents the PDCCH-to-PUSCH timing (i.e., the slot offset between the DCI and the scheduled PUSCH) in slot units, mappingType represents the PUSCH mapping type, startSymbolAndLength or StartSymbol and length represent the start symbol and length of the PUSCH, and numberOfRepetitions may represent the number of repetitions applied to the PUSCH transmission. The base station may indicate at least one of the entries of the table for the time domain resource allocation information to the terminal through L1 signaling (e.g., downlink control information (DCI)) (e.g., by a 'time domain resource allocation' field in the DCI). The terminal may obtain the time domain resource allocation information for the PDSCH or PUSCH based on the DCI received from the base station.

[0174] Below, we describe a method for reducing SSB density through dynamic signaling to save base station energy in 5G systems.

[0175] FIG. 10 is a diagram illustrating an example of a method for resetting SSB transmission through dynamic signaling according to an embodiment.

[0176] Referring to FIG. 10, the terminal receives ssb-PositionsInBurst = '11110000' (1002) from the base station through upper layer signaling (SIB1 or ServingCellConfigCommon), and a maximum of two synchronization signal blocks at a subcarrier spacing of 30 kHz can be transmitted within 0.5 ms (or 1 slot length when 1 slot consists of 14 OFDM symbols), and accordingly, the terminal can receive 4 synchronization signal blocks within 1 ms (or 2 slot lengths when 1 slot consists of 14 OFDM symbols). At this time, the base station can reset the SSB transmission configuration information by broadcasting the bitmap '1010xxxx' (1004) through the Group / Cell common DCI (Group / Cell common DCI, 1003) having the nwes-RNTI (network energy saving-radio network temporary identifier, or es-RNTI) to reduce the density of SSB transmission for energy saving. At this time, the transmission of SS block#1 (1005) and SSblock#3 (1006) can be canceled based on the bitmap (1004) set as the Group / Cell common DCI. The above FIG. 10 provides a method (1001) for resetting SSB transmission through the Group / Cell common DCI based on the bitmap.

[0177] In addition, the base station can reset the ssb-periodicity set through upper layer signaling via group / cell common DCI. In addition, timer information for indicating the application time of the group / cell common DCI can be additionally set, and SSB can be transmitted through the SSB transmission information reset to the group / cell common DCI during the set timer. Afterwards, when the timer expires, the base station can operate based on the SSB transmission information set through the existing upper layer signaling. This may correspond to an operation of changing the setting from normal mode to energy saving mode through the timer, and may correspond to the resetting of the SSB configuration information due to this. Alternatively, the base station can set the application time and period of the SSB configuration information reset through the group / cell common DCI to the terminal using offset and interval information. In this case, the terminal may not monitor SSB during the set interval from the moment of receiving the group / cell common DCI to the moment of applying the offset.

[0178] Below, we describe a BWP or BW adaptation method through dynamic signaling for base station energy saving in 5G systems.

[0179] FIG. 11 is a diagram illustrating an example of a method for resetting BWP and BW through dynamic signaling according to an embodiment.

[0180] Referring to Figure 11, the terminal can operate in BWP or BW activated through upper layer signaling and L1 signaling from the base station (1101). For example, the terminal can operate in a fixed power PSD. B It can operate through a full BW of 100MHz. At this time, the base station uses the same power PSD for energy saving. BThe BW and BWP can be adjusted to activate a narrower BW of 40 MHz for the terminal (1102). At this time, the BW or BWP adjustment operation for energy saving of the base station can be set to match the BWP and BW settings that are set UE-specifically through the group common DCI and the cell specific DCI (1103). For example, UE#0 and UE#1 can have different BWP configurations and locations. At this time, in order to save energy by reducing the BW used by the base station, the base station can set the BW and BWP of all terminals to be the same. At this time, the BWP or BW in the operation for energy saving can be set to one or more, and this can be used to set the BWP for each terminal group.

[0181] Below, a discontinuous reception (DRX) alignment method through dynamic signaling for base station energy saving in a 5G system is described.

[0182] FIG. 12 is a diagram illustrating an example of a method for resetting DRX through dynamic signaling according to an embodiment.

[0183] Referring to Fig. 12, the base station can configure DRX for each terminal specifically through upper layer signaling. For example, each terminal can be configured with different drx-LongCycle or drx-ShortCycle, drx-onDurationTimer, and drx-InactivityTimer. After that, the base station can configure UE-specific DRX settings for energy saving in a UE group-specific or cell-specific manner through L1 signaling (1201). Through this, the base station can achieve the same effect of saving power for the terminal through DRX for energy saving.

[0184] Below, we describe the DTx (discontinuous transmission) operation to reduce energy consumption of base stations in 5G systems.

[0185] FIG. 13 is a diagram illustrating an example of a DTx method for base station energy saving.

[0186] Referring to FIG. 13, the base station can configure DTx for energy saving through higher layer signaling (e.g. new SIB or RRC signaling for DTx) and L1 signaling (DCI). At this time, the base station can set dtx-onDurationTimer (1305) for transmitting a reference signal for measuring PDCCH for scheduling DL SCH for DTx operation or RRM measurement, beam management and path loss, etc., dtx-InactivityTimer (1306) for receiving PDSCH after receiving PDCCH for scheduling DL SCH, information for setting a synchronization signal (SS, 1303) for synchronization before dtx-onDurationTimer, dtx-offset (1304) for setting an offset between SS and dtx-onDurationTimer, and dtx-(Long)Cycle (1302) for DTx to operate periodically based on the above setting information. At this time, dtx-cycle can be set to multiple long cycles and short cycles. During the operation of the above DTx, the base station considers the state of the transmitter to be off (or inactive), and therefore may not transmit DL CCH, SCH, and DL RS. That is, the base station may transmit downlink (PDCCH, PDSCH, RS, etc.) only during SS, dtx-onDurationTimer, and dtx-InactivityTimer during the DTx operation. At this time, the SS-gapbetweenBurst or the number of SS bursts may be additionally set as additional information of the configured SS.

[0187] Below, a method for activating a base station through a gNB WUS (wake-up signal) during the base station's inactive mode to reduce energy consumption of the base station in a 5G system is described.

[0188] Fig. 14 is a diagram for explaining an example of the operation of a base station according to gNB WUS.

[0189] Referring to FIG. 14, the base station can keep the transmitter end in an off (or inactive) state during the base station's inactive state (or sleep mode) for energy saving. Thereafter, the base station can receive a gNB WUS (1402) from the terminal to activate the base station's sleep mode. Thereafter, when the base station receives the WUS (1402) from the terminal through the Rx terminal, the base station can turn the Tx terminal on (or active) (1403). Thereafter, the base station can perform downlink transmission to the terminal. At this time, the base station can perform synchronization after Tx on and perform control information and data transmission. In addition, at this time, various uplink signals, such as a physical random access channel (PRACH), a scheduling request (SR) on a physical uplink control channel (PUCCH), and a PUCCH including an acknowledgement (ACK), can be considered as the gNB WUS. Through the above method, the base station can save energy, and at the same time, the terminal can improve latency.

[0190] At this time, the base station can set a WUS occasion for receiving the gNB WUS and a synchronization reference signal (sync RS) for synchronization before the terminal transmits the gNB WUS. At this time, the synchronization reference signal may be considered as SSB, TRS (tracking RS), Light SSB (PSS and SSS), consecutive SSBs, or a new RS (e.g., continuous PSS and SSS), and the WUS may be considered as PRACH, a scheduling request on PUCCH, or a sequence-based signal. The synchronization reference signal (1504) for the terminal to activate the deactivation mode for energy saving of the base station and the WUS occasion for receiving the WUS may be repeatedly set in a cycle of a WUS-RS cycle (1405). For the example in FIG. 15, one embodiment illustrates a 1-to-1 mapping of a synchronization reference signal and a WUS occasion, but is not limited thereto, and may be N-to-1 mapping, 1-to-N mapping, or N-to-M mapping.

[0191] Below, a method for dynamically turning on / off spatial domain elements (i.e., antennas, PAs, or TxRUs) of a base station to save base station energy in a 5G system is described.

[0192] FIG. 15 is a diagram illustrating an example of a spatial domain (SD) adaptation method of a base station for energy saving according to an embodiment.

[0193] Referring to FIG. 15, the base station can adjust the transmit antenna port (Tx antenna port per RU) for energy saving. Since the PA of the base station accounts for most of the energy consumption of the base station, the base station can turn off the transmit antenna to save energy (1501). At this time, the base station can adjust the number of activated transmit antennas for each terminal group or terminal by referring to the RSRP (reference signal received power), CQI (channel quality indicator), and RSRQ (reference signal received quality) of the terminal to determine whether the transmit antenna can be turned off and transmit a signal. At this time, the base station can set beam information and reference signal information (CSI resource or CSI report setting) according to the on / off of the antenna to the terminal through upper layer signaling (RRC signaling) or DCI. In addition, the terminal can set different antenna information for each BWP and reset the antenna information according to the BWP change. Additionally, the base station may receive CSI feedback from the terminal to determine whether SD adaptation is possible and determine SD adaptation based on the CSI feedback. At this time, the base station may receive multiple CSI feedbacks from the terminal based on antenna structure hypotheses of multiple antenna patterns for SD adaptation.

[0194] More specifically, the base station can apply two types of SD adaptation for energy saving (1502). Type 1 SD adaptation (1503) is that the base station changes the number of antenna ports while maintaining the number of physical antenna elements per antenna port (i.e., logical port). At this time, the RF characteristics (e.g., transmit power, beam) per port of the base station can be the same. Therefore, the terminal can perform the measurement by combining the CSI-RS of the same port during the CSI measurement (e.g., L1-RSRP, L3-RSRP, etc.). For example, each port of CSI-RS #0 and CSI-RS #1 can include the same number of physical antenna elements.

[0195] Another method, Type 2 SD adaptation (1504), is that the base station has the same number of antenna ports (i.e., logical ports) and turns on / off physical antenna elements per port. In this case, the RF characteristics of each port will change, and the terminal must perform measurements separately for the CSI-RS of the same port when Type 2 SD adaptation is applied and when it is not, during CSI measurement. For example, the number of ports in CSI-RS #0 and CSI-RS #1 is maintained, but the number of physical antenna elements corresponding to each port is changed.

[0196] The base station can save energy through the two representative types of SD adaptation methods mentioned above.

[0197] Through the above methods, energy consumption of the base station can be reduced. Furthermore, the above methods can be configured simultaneously through one or more combinations.

[0198] Various embodiments of the present disclosure provide a new cell definition and on-demand cell activation method through WUS transmitted by a terminal to reduce energy consumption of a base station in a wireless communication system.

[0199] Various embodiments of the present disclosure define carrier selection methods for WUS to activate on-demand cells and WUS occasions (WOs) for WUS transmission and reception. Furthermore, retransmission and repetition operations for WUS are provided. This allows the base station to conserve energy by maintaining more components of non-on-demand cells in an inactive state for longer periods of time.

[0200] Additionally, when describing the present disclosure, detailed descriptions of related functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined based on the functions of the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the contents of this specification.

[0201] In the following description of the present disclosure, upper layer signaling may be signaling corresponding to at least one or a combination of one or more of the following signaling.

[0202] - MIB

[0203] - SIB or SIB

[0204] - RRC

[0205] - MAC (medium access control) CE (control element)

[0206] In addition, L1 signaling may be signaling corresponding to at least one or a combination of one or more signaling methods using the following physical layer channels or signaling.

[0207] - PDCCH

[0208] - DCI

[0209] - Terminal-specific DCI

[0210] - Group common DCI

[0211] - Common DCI

[0212] - Scheduling DCI (e.g. DCI used for scheduling downlink or uplink data)

[0213] - Non-scheduled DCI (e.g. DCI not intended for scheduling downlink or uplink data)

[0214] - PUCCH

[0215] - UCI (uplink control information)

[0216] In the present disclosure, determining the priority between A and B may be referred to in various ways, such as selecting a higher priority according to a predetermined priority rule and performing an action corresponding to it, or omitting or dropping an action for a lower priority.

[0217] The term "slot" used in the present disclosure below is a general term that can refer to a specific time unit corresponding to a transmit time interval (TTI), and specifically can mean a slot used in a 5G NR system, or a slot or subframe used in a 4G LTE system. In the present disclosure below, the term "port" can be used interchangeably with "antenna port." In the present disclosure below, the above examples are described through a number of embodiments, but they are not independent, and one or more embodiments can be applied simultaneously or in combination.

[0218] Below, the base station in a 5G or 6G system describes the concept of cells with new different functions to reduce energy consumption.

[0219] FIG. 16 is a diagram illustrating an example of a concept of cells having different functions for energy saving according to an embodiment.

[0220] Referring to Fig. 16, the concept (1601) of cells with different functions is illustrated. The base station can define cell#0(1600) and cell#1-X (e.g., cell#1-1(1610), cell#1-2(1620)) with different functions. Cell type 1 (e.g., cell#0(1600), Access / sync cell) only manages the mobility and synchronization and initial access operations of the terminal, and in a cell of cell type 1, packet transmission for processing traffic may not be performed or only limited packets may be transmitted. More specifically, the base station can periodically transmit SSB and new synchronization signal for the terminal in idle / inactive RRC state through cell#0, and also paging and system information may be transmitted through cell#0. The above paging and system information may include configuration information for cell #1-x capable of processing packets, for example, at least one of carrier frequency, physical cell ID, and WUS configuration information for cell #1-x. The WUS configuration information may include at least one of information about WUS and information about WUS occasion.

[0221] Cell type 2 (e.g., cell #1-x (1610, 1620, 1630), Data cell) can process packets of terminals and base stations. More specifically, the base station can process packets of terminals in connected RRC state through cell #1-X. Therefore, a cell of cell type 2 can be selectively activated only when there are packets according to traffic on-demand. If the base station initially activates cell #1-X for packet processing, cell #1-X transmits SS (synchronization signal, e.g., SSB, CSI-RS, TRS, or new SS) to synchronize the terminal and cell #1-X, and a terminal that has performed initial access to cell #0 or is synchronized to cell #0 can receive SS of cell #1-x and handover to cell #1-x. At this time, cell 1-X to be activated on-demand can be determined by the base station serving cell #0, the base station serving cell #1-X, or the terminal attached to cell #0.

[0222] A single base station may support only cell type 1, only cell type 2, or both cell type 1 and cell type 2. Additionally, one or more cell type 2 cells may be connected to one or more cell type 1 cells. Additionally, coordination may occur between cell type 1 cells to activate cell type 2 cells.

[0223] Through the above methods and the new cell concept, the energy consumption of the network system can be minimized.

[0224] Through embodiments of the present disclosure, a cell selection method is provided for a terminal to process packets appropriately according to traffic in a cell deployment situation with cells performing different functions. More specifically, the present disclosure provides a cell selection method and a signaling method by a base station or a terminal.

[0225] <Example 1>

[0226] As a first embodiment of the present disclosure, a cell selection method and signaling procedure for energy saving at a base station in a 5G or 6G system are described. Through the above embodiment, the base station can activate appropriate data cells for a terminal, maximizing energy saving effects and ensuring service performance.

[0227] FIG. 17 is a diagram illustrating an example of an on-demand cell selection method for energy saving of a base station according to an embodiment.

[0228] Referring to FIG. 17, for energy saving, cell type 2 (e.g., data cells) capable of packet transmission may be configured to process traffic within the coverage of cell type 1 (e.g., access / sync cell) that performs mobility and initial connection functions. In this case, after a terminal connects to an access / sync cell, an appropriate data cell for processing traffic may be selected using one or a combination of the following methods.

[0229] [Method 1]

[0230] The base station can select an appropriate data cell for each terminal based on the geometry information of the terminal (e.g., location information, sector information, and beam-based direction information, etc.) (1700). For example, when the terminal (1730) is initially connected to Access / Sync cell#0 (1710), the terminal can handover or connect from Access / Sync cell#0 to one of data cells#1 to#3 (1720, 1722, 1724) within Access / Sync cell#0 for packet processing. The base station can select an appropriate data cell for the terminal as the connection cell, and the base station can activate the selected data cell. At this time, in order for the base station to determine that data cell#1 is an appropriate cell for the UE, for example, the base station can select data cell#1 (1720) using beam information (beam direction information) for synchronization used / reported by the terminal in the Access / Sync cell.

[0231] On-demand cell selection based on an Access / Sync cell base station can be performed through the above method 1.

[0232] [Method 2]

[0233] The terminal (1780) can activate a data cell for transmitting and receiving packets via UL WUS for traffic processing (1750). For example, a terminal connected to Access / Sync cell #0 (1760) can activate surrounding data cells (1770, 1772, 1774) for traffic processing. To this end, the terminal can transmit a WUS to activate the data cell. More specifically, the WUS can be a sequence-based signal or a conventional PUCCH, PRACH, or similar signal, and the base station of the data cell can have a WUS receiver (WUS receiver, WUR) for receiving a separate WUS. In addition, the terminal can repeatedly transmit or retransmit the WUS, and the terminal can transmit the WUS by determining the transmission power and carrier frequency of the WUS based on the information configured through the Access / Sync cell. The data cell-related information configured by the terminal through the Access / Sync cell can include, for example, at least one of the following information.

[0234] - WUS occasion duration per carrier: WUS monitoring duration corresponding to carrier

[0235] - Periodicity of WUS occasion: 20 ms or 40 ms like as RACH occasion periodicity

[0236] - Start of WUS occasion per WUS design: system frame number (SFN)

[0237] - WUS response window: symbol level, slot level or time level value

[0238] - Carrier frequency and Carrier frequency list (for WUS)

[0239] - Carrier frequency and Carrier frequency list (for WUS response)

[0240] - Data cell ID or physical cell ID (PCI) of data cell

[0241] - Time adjustment group between Access / sync cell and Data cell

[0242] -Data cell position information

[0243] - Number of WUS repetition

[0244] - Number of WUS retransmission

[0245] - Additional WUS occasion duration for WUS repetition

[0246] -WUS response transmission power

[0247] At this time, the base station serving the data cell (Data cell#1 (1770), Data cell#3 (1774)) that received the WUS from the terminal becomes activated, transmits SS to the terminal, and can perform data transmission and reception for subsequent packets. In the above method, after receiving the WUS, it is possible to determine whether the data cell or access cell is activated based on measurement information such as RSRP for the WUS, or after all data cells that received the WUS are activated, the terminal can receive SS from one or more activated data cells to select an appropriate data cell for data transmission and reception.

[0248] By using the above methods, a base station serving an inactive cell can save energy by selecting an appropriate data cell for the terminal, and the terminal can receive service through the selected data cell.

[0249] An embodiment of the present disclosure provides a signaling procedure for data cell selection based on the WUS.

[0250] FIG. 18A is a diagram illustrating an example of a procedure for on-demand cell selection for energy saving of a base station according to an embodiment of the present disclosure.

[0251] Referring to FIG. 18A, a terminal (1802) can perform data cell selection through WUS transmission (1800). A sync / access cell (1804) may always be activated (1820, Tx / Rx on, which may mean power on of transmission RF and reception RF devices including a modem), and data cells cell2-A (1806), cell2-B (1808), and cell2-C (1810) may have RF for transmission and reception powered off, but WUR may always be on (1822). Here, power off may be understood as deep / ultra deep sleep. The deep / ultra deep sleep may mean that most of the components of the base station are powered off, and for example, the modem, backhaul, memory, cooler, etc. may all be turned off. In addition, the sync / access cell and the data cell may exchange information for network energy saving (1826). Information for network energy saving that is transmitted and received between the sync / access cell and the data cell may include at least one of the following information: a network energy saving scheme applied to each cell, information about WUS that each cell can support, and at least one of the information included in the data cell-related information described above.

[0252] After powering on (1824) or receiving SS in idle RRC state mode and selecting a cell to connect to (1828), the terminal can perform a RACH procedure for initial connection to an Access / Sync cell (1830). In addition, the terminal can receive configuration information of a data cell associated with the corresponding cell from the Access / Sync cell (1832). The configuration information of the data cell can refer to the data cell-related information described above. Thereafter, based on the received data cell configuration information, the terminal can transmit a WUS to one or more data cells (1834). At this time, base stations that have received the WUS transmitted from the terminal can be activated (Tx / Rx On) and transmit a reference signal for synchronization (or connection) to the terminal (1836). The terminal can measure the reference signal, select a data cell based on the measurement result (1838), and perform a handover (or connection) to the data cell (1840).

[0253] The above flowchart illustrates exemplary methods that can be implemented according to the principles of the present disclosure, and various modifications may be made to the methods depicted in the flowcharts herein. For example, although depicted as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other instances, steps may be omitted or replaced with other steps.

[0254] FIG. 18b is a diagram illustrating an example of a procedure for on-demand cell selection for energy saving of a base station according to an embodiment of the present disclosure.

[0255] Alternatively, the base station of the access cell may perform data cell selection (1850) based on the WUS transmitted by the terminal (1852). The sync / access cell (1854) may always be active (Tx / Rx on, 1870), and the data cells cell2-A (1856), cell2-B (1858), and cell2-C (1860) may have RF for transmission and reception powered off, but the WUR may always be on (1872). In addition, the sync / access cell and the data cell may exchange information for network energy saving (1876). The information for the network energy saving may refer to the above-described content.

[0256] After powering on (1874) or in an idle RRC state, the terminal may receive SS and select a cell to connect to (1878), and then perform a RACH procedure for initial connection to the Access / Sync cell (1880). Furthermore, the terminal may receive configuration information for a data cell associated with the cell from the Access / Sync cell (1882). The configuration information for the data cell may refer to the data cell-related information described above. Thereafter, based on the received data cell configuration information, the terminal may transmit a WUS to one or more data cells (1884).

[0257] At this time, the base stations serving the data cell that received the WUS transmitted from the terminal can report the measurement results of the WUS measurement, such as information including RSRP and RSRQ, to the Access / Sync cell (1886). At this time, whether to report to the Access / Sync cell based on the WUS measurement can be determined by the data cell based on the WUS measurement results. Afterwards, the Sync / Access cell can determine a data cell based on the received WUS measurement report (1888) and activate the data cell (1890). The activated (Tx / Rx On) data cell can transmit a reference signal for synchronization (or connection) to the terminal (1892). The terminal can receive the reference signal from the data cell and hand over (or connect) to the data cell (1894). Alternatively, if the reception status of the reference signal from the data cell is poor, the terminal can transmit the WUS again.

[0258] The above flowchart illustrates exemplary methods that can be implemented according to the principles of the present disclosure, and various modifications may be made to the methods depicted in the flowcharts herein. For example, although depicted as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other instances, steps may be omitted or replaced with other steps.

[0259] Through the above methods, a terminal or base station can select an appropriate data cell based on the terminal's WUS. This allows for the selection of a specific, optimal data cell for each terminal, allowing cell selection that takes into account the channel between the data cell and the terminal. This allows the base station to save energy by utilizing inactive data cells, while the terminal can enjoy high-performance service.

[0260] <Example 2>

[0261] As a second embodiment of the present disclosure, a carrier selection method and a WUS configuration method for cell selection for energy saving at a base station in a 5G or 6G system are described. Through the above embodiment, the base station can activate appropriate data cells for a terminal, thereby maximizing energy saving effects and ensuring service performance.

[0262] FIG. 19a and FIG. 19b are diagrams illustrating an example of a WUS transmission method for activating a data cell for energy saving of a base station according to an embodiment.

[0263] Referring to FIGS. 19a and 19b, the terminal can determine a carrier (or / and a frequency domain resource allocated to the carrier) and a WUS occasion (or a time domain resource allocated for WUS transmission) to transmit the WUS based on the WUS configuration information for data cell activation received from the Access / Sync cell, and transmit the WUS. At this time, the WUS can be repeatedly transmitted or retransmitted on different carriers or occasions. The following describes a cell activation operation based on WUS retransmission and a cell activation operation based on WUS repeated transmission.

[0264] FIG. 19a is a diagram illustrating an example of a WUS transmission method for activating a data cell for energy saving of a base station according to an embodiment.

[0265] [WUS retransmission-based data cell activation (1900)]

[0266] After the RACH procedure (1910) for initial access to the Access / Sync cell, the terminal (1908) may receive WUS configuration information related to the data cell associated with the corresponding cell from the Access / Sync cell (1902) (1912). At this time, the WUS configuration information (WUS Config) for the corresponding data cell may include candidate carrier information of the corresponding data cell and information on WUS occasion and WUS format for each carrier. In addition, the terminal may be configured with a WUS response window (WUS response window) for monitoring feedback on the WUS after WUS transmission. The WUS response window configuration information may be included in the WUS configuration information or the value of the WUS response window may be determined based on UE capability. For example, the WUS configuration information may include at least one of the following information.

[0267] - WUS occasion duration per carrier: WUS monitoring duration corresponding to carrier

[0268] - Periodicity of WUS occasion: 20 ms or 40 ms like as RACH occasion periodicity

[0269] - Start of WUS occasion per WUS design: system frame number (SFN)

[0270] - WUS response window: symbol level, slot level or time level value

[0271] - Carrier frequency and Carrier frequency list (for WUS)

[0272] - Carrier frequency and Carrier frequency list (for WUS response)

[0273] - Data cell ID 또는 physical cell ID (PCI) of data cell

[0274] - Time adjustment group between Access / sync cell and Data cell

[0275] - Data cell position information

[0276] - Number of WUS repetition

[0277] - Number of WUS retransmission

[0278] - Additional WUS occasion duration for WUS repetition

[0279] - WUS response transmission power

[0280] Afterwards, when the terminal receives {Cell#2(28GHz)(1906), Cell#1(3.5GHz)(1904)} as candidate carriers of the data cell from the base station, the terminal can perform the first WUS transmission at WUS occasion #2(1914) through cell#2 of 28GHz based on the above configuration information. If the terminal does not receive any feedback (e.g., Ack) during the WUS response window#0 (1916) corresponding to Cell#2 after the first WUS transmission, the terminal can perform WUS retransmission at WUS occasion #1(1918) through Cell#1(3.5GHz). If the terminal receives feedback (Ack, 1922) during the WUS response window#1(1920) corresponding to Cell#1 after the WUS retransmission, the terminal can handover (or connect) to Cell#1. The terminal can receive the priority for WUS transmission / retransmission of the candidate carriers from the Access / Sync cell. The above priority information may be included in the WUS configuration information or may be predetermined. The terminal may then perform a WUS retransmission operation based on the above priority.

[0281] FIG. 19b is a diagram illustrating another example of a WUS transmission method for activating data cells for energy saving of a base station according to an embodiment.

[0282] [WUS repetition-based data cell activation (1950)]

[0283] The terminal (1958) may receive WUS configuration information related to a data cell associated with the Access / Sync cell (1952) from the Access / Sync cell after the RACH procedure (1960) in order to initially access the Access / Sync cell. At this time, the WUS configuration information (WUS Config) for the data cell may include candidate carrier information of the data cell and information on WUS occasion and WUS format for each carrier. In addition, the terminal may be configured with a WUS response window for monitoring feedback on the WUS after WUS transmission. The WUS response window may be included in the WUS configuration information or the value of the WUS response window may be determined based on the terminal capability. The above-described content may be referenced for the WUS configuration information.

[0284] Afterwards, when the terminal is set to {Cell#2(28GHz)(1956), Cell#1(3.5GHz)} as the candidate carrier of the data cell from the base station and 2 is set as the norepetition (number of repetitions) of WUS, based on the above setting information, the terminal can perform the first WUS transmission at WUS occasion #1(1864) through cell#1(1954) of 3.5GHz and then repeatedly transmit the WUS at WUS occasion #2(1966) through cell#2(1956) of 28GHz. The terminal can monitor the feedback during the corresponding WUS response window#0(1968) from the time of transmitting the WUS in Cell#1 and can continuously monitor the feedback for the WUS response window#1(1970) after transmitting the WUS in Cell#2. Afterwards, when the terminal receives an Ack feedback (1972) including the Cell#2 index in WUS response window#1, the terminal can handover (or connect) to Cell#2.

[0285] At this time, the carrier order (or carrier / data cell priority) for WUS repeat transmission can be set from the Access / Sync cell (in which case the priority information can be included in the WUS configuration information) or can be sorted from a low carrier frequency or a high carrier frequency according to traffic. In addition, the gap between WUS repetitions can be set from the base station to the terminal or determined by the terminal capability, taking into account the carrier switching time.

[0286] Through the above two methods, the terminal can determine the carrier of the data cell and activate the data cell through the WUS. In addition, the WUS occasions can overlap by carrier, and the carrier frequency of the WUS response window can be the carrier frequency of the Access / Sync cell, the carrier frequency of the corresponding data cell, or the carrier frequency for a specific WUS, and the terminal can receive and monitor the feedback of the WUS through the carrier frequency.

[0287] <Example 3>

[0288] The third embodiment of the present disclosure provides a cell selection procedure for energy saving at a base station in a 5G or 6G system. More specifically, an example of a procedure for cell selection and WUS transmission at a terminal and a base station for energy saving at a base station in a 5G or 6G system is described.

[0289] FIG. 20 is a flowchart illustrating an example of an operation of a terminal that applies a cell selection method for energy saving of a base station in a 5G or 6G system to which the present disclosure is applied.

[0290] The terminal can perform initial access and synchronization based on cell type 1 (e.g., Cell#0 or Access / Sync cell) (2001). Thereafter, the terminal can receive configuration information for a cell of cell type 2 (e.g., Cell#1-X or Data cell) through upper layer signaling and L1 signaling from cell type 1 (2002). At this time, the configuration information may include configuration information of WUS. The configuration information for the data cell and the WUS configuration information may refer to the contents described above. The terminal can check the WUS occasion and carrier for WUS transmission based on the configuration information (2003). The terminal can transmit the WUS through the selected carrier and monitor the WUS feedback during the WUS response window (2004). The terminal determines whether the WUS feedback (Ack) has been received, and if the terminal receives the WUS feedback during the WUS response window, the terminal can access the corresponding data cell (2005). If the terminal does not receive feedback from the WUS or receives a Nack (negative acknowledgment), the terminal may retransmit or / and repeatedly transmit the WUS and monitor the WUS feedback again (2006).

[0291] FIG. 21A is a flowchart illustrating an example of a base station operation serving a cell of cell type 1 that applies a cell selection method for energy saving of a base station in a 5G or 6G system to which the present disclosure applies.

[0292] Referring to FIG. 21A, in order to support cell type 1, a base station may transmit a periodic reference signal to a terminal for initial access & synchronization and mobility support (2101). Such a periodic reference signal may be, for example, at least one of SSB, PSS, SSS, or a newly defined SS. At this time, paging and system information may also be transmitted periodically from the base station. The base station may transmit configuration information for a cell of cell type 2 to the terminal (2102). The configuration information may include WUS configuration information. The configuration information for the data cell and the WUS configuration information may refer to the contents described above. Thereafter, the base station may receive a WUS measurement report including the result of measuring the WUS transmitted by the terminal from a cell of cell type 2 (or a base station serving the cell) and perform data cell selection (2103). If the cell selection operation of the base station is not performed, step 2103 may be omitted.

[0293] FIG. 21b is a flowchart illustrating an example of a base station operation serving a cell of cell type 2 for energy saving of the base station in a 5G or 6G system to which the present disclosure applies.

[0294] Referring to FIG. 21b, the base station can monitor WUS at a WUS occasion through WUR based on WUS configuration information set through the Access / Sync cell or predetermined WUS-related information (2104). The WUS configuration information can refer to the content described above. At this time, the Tx and Rx RF of the base station may be powered off, but the WUR may be powered on. Thereafter, when the base station receives the WUS, it measures the WUS and determines whether the cell is activated to determine whether the main radio is activated, and / or can report the WUS measurement to the Access / Sync cell (2105). Thereafter, the base station can compare the WUS measurement result, for example, RSRP and RSRQ, with a threshold value that is predetermined or set by the base station serving the cell type 1 cell (2106), and if the WUS measurement result is greater than (or greater than or equal to) the threshold value, it can transmit an Ack to the terminal (2107). Afterwards, the cell type 2 base station can be activated after the Ack transmission and the terminal can be attached to the cell of the cell type 2 (2107).

[0295] The above-described flowcharts illustrate exemplary methods that can be implemented according to the principles of the present disclosure, and various modifications may be made to the methods depicted in the flowcharts herein. For example, although depicted as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other instances, steps may be omitted or replaced with other steps.

[0296] FIG. 22 is a block diagram of a terminal according to one embodiment of the present disclosure.

[0297] Referring to FIG. 22, a terminal (2200) may include a transceiver (2201), a control unit (e.g., a processor) (2202), and a storage unit (e.g., a memory) (2203). The transceiver (2201), the control unit (2202), and the storage unit (2203) of the terminal (2200) may operate according to at least one or a combination of the methods corresponding to the above-described embodiments. However, the components of the terminal (2200) are not limited to the illustrated example. According to other embodiments, the terminal (2200) may include more or fewer components than the components described above. In addition, in certain cases, the transceiver (2201), the control unit (2202), and the storage unit (2203) may be implemented in the form of a single chip.

[0298] The transceiver (2201) may, according to one embodiment, be composed of a transmitter and a receiver. The transceiver (2201) may transmit and receive signals with a base station. The signals may include control information and data. The transceiver (2201) may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-downconverts the received signal. The transceiver (2201) may receive a signal through a wireless channel and output the signal to the control unit (2202), and may transmit the signal output from the control unit (2202) through the wireless channel.

[0299] The control unit (2202) may control a series of procedures that the terminal (2200) may perform according to the embodiments of the present disclosure described above. For example, the control unit (2202) may perform or control the operation of the terminal to perform at least one or a combination of methods according to the embodiments of the present disclosure. The control unit (2202) may include at least one processor. For example, the control unit (2202) may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls an upper layer (e.g., an application).

[0300] The storage unit (2203) can store control information (e.g., information related to channel estimation using DMRSs transmitted on PUSCH included in a signal acquired from the terminal (2200)) or data, and can have an area for storing data required for controlling the control unit (2202) and data generated during control by the control unit (2202).

[0301] Figure 23 is a block diagram of a base station according to one embodiment.

[0302] Referring to FIG. 23, a base station (2300) may include a transceiver (2301), a control unit (e.g., a processor) (2302), and a storage unit (e.g., a memory) (2303). The transceiver (2301), the control unit (2302), and the storage unit (2303) of the base station (2300) may operate according to at least one or a combination of methods corresponding to the above-described embodiments. However, the components of the base station (2300) are not limited to the illustrated example. According to other embodiments, the base station (2300) may include more or fewer components than the components described above. In addition, in certain cases, the transceiver (2301), the control unit (2302), and the storage unit (2303) may be implemented in the form of a single chip.

[0303] The transceiver (2301) may, according to one embodiment, be composed of a transmitter and a receiver. The transceiver (2301) may transmit and receive signals with a terminal. The signals may include control information and data. The transceiver (2301) may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-converts the received signal. The transceiver (2301) may receive a signal through a wireless channel and output the signal to the control unit (2302), and may transmit the signal output from the control unit (2302) through the wireless channel.

[0304] The control unit (2302) may control a series of procedures so that the base station (2300) can operate according to the embodiments of the present disclosure described above. For example, the control unit (2302) may perform or control the operation of the base station to perform at least one or a combination of methods according to the embodiments of the present disclosure. The control unit (2302) may include at least one processor. For example, the control unit (2302) may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls an upper layer (e.g., an application).

[0305] The storage unit (2303) can store control information (e.g., information related to channel estimation generated using DMRSs transmitted on a PUSCH determined by the base station (2300), data, control information received from a terminal, or data, and can have an area for storing data required for controlling the control unit (2302) and data generated during control by the control unit (2302).

Claims

1. In a method performed by a terminal of a communication system, A step of performing an initial connection procedure with a first base station corresponding to the first cell; A step of receiving wake up signal (WUS) setting information from the first base station; A step of transmitting WUS to a second base station corresponding to a second cell based on the above WUS setting information; and Comprising a step of monitoring a response signal (acknowledgement) corresponding to the above WUS during the WUS response window, A method characterized in that the WUS configuration information includes at least one of carrier frequency information of the second cell, WUS transmission time (occasion) information, WUS format information, and WUS response window configuration information.

2. In paragraph 1, A method characterized by further comprising the step of performing a procedure for connection with the second base station when the above response signal is received during the WUS response window.

3. In paragraph 1, A method characterized by further comprising the step of transmitting a WUS to a base station corresponding to another cell based on the WUS configuration information if the above response signal is not received during the WUS response window.

4. In paragraph 1, A method characterized in that the first cell corresponds to a cell type for connection and synchronization, and the second cell corresponds to a cell type for data transmission and reception.

5. In a method performed by a first base station corresponding to a first cell of a communication system, Step of performing an initial connection procedure with the terminal; and Including a step of transmitting wake up signal (WUS) setting information to the terminal, The first base station corresponding to the first cell is connected to the second base station corresponding to the second cell, WUS according to the above WUS setting information is transmitted from the terminal to the second base station, A method characterized in that the WUS configuration information includes at least one of carrier frequency information of the second cell, WUS transmission time (occasion) information, WUS format information, and WUS response window configuration information.

6. In paragraph 5, A method characterized in that the first cell corresponds to a cell type for connection and synchronization, and the second cell corresponds to a cell type for data transmission and reception.

7. In a method performed by a second base station corresponding to a second cell of a communication system, A step of receiving a wake up signal (WUS) from a terminal; A step of transmitting a response signal (acknowledgement) to the WUS to the terminal during the WUS response window; and A step of performing a connection procedure for the terminal and the second cell of the terminal, WUS related information is transmitted from the second base station to the first base station corresponding to the first cell, A method characterized in that the WUS related information includes at least one of carrier frequency information of the second cell, WUS transmission time (occasion) information, WUS format information, and WUS response window setting information.

8. In paragraph 7, A method characterized in that the first cell corresponds to a cell type for connection and synchronization, and the second cell corresponds to a cell type for data transmission and reception.

9. At the terminal of the communication system, Transmitter and receiver; and A control unit connected to the above transceiver and including one or more processors, wherein the control unit: Perform an initial connection procedure with the first base station corresponding to the first cell, Receive wake up signal (WUS) setting information from the first base station, Transmitting WUS to the second base station corresponding to the second cell based on the above WUS setting information, and It is set to monitor the response signal (acknowledgement) corresponding to the above WUS during the WUS response window, A terminal characterized in that the WUS configuration information includes at least one of carrier frequency information of the second cell, WUS transmission time (occasion) information, WUS format information, and WUS response window configuration information.

10. In paragraph 9, A terminal characterized in that the control unit is set to perform a procedure for connection with the second base station when the response signal is received during the WUS response window.

11. In paragraph 9, A terminal characterized in that the control unit is set to transmit a WUS to a base station corresponding to another cell based on the WUS setting information when the response signal is not received during the WUS response window.

12. In paragraph 1, A terminal characterized in that the first cell corresponds to a cell type for connection and synchronization, and the second cell corresponds to a cell type for data transmission and reception.

13. In the first base station corresponding to the first cell of the communication system, Transmitter and receiver; and A control unit connected to the above transceiver and including one or more processors, wherein the control unit: Perform the initial connection procedure with the terminal, It is set to transmit wake up signal (WUS) setting information to the above terminal, The first base station corresponding to the first cell is connected to the second base station corresponding to the second cell, WUS according to the above WUS setting information is transmitted from the terminal to the second base station, The WUS configuration information includes at least one of carrier frequency information of the second cell, WUS transmission time (occasion) information, WUS format information, and WUS response window configuration information, A first base station, characterized in that the first cell corresponds to a cell type for connection and synchronization, and the second cell corresponds to a cell type for data transmission and reception.

14. In the second base station corresponding to the second cell of the communication system, Transmitter and receiver; and A control unit connected to the above transceiver and including one or more processors, wherein the control unit: Receive a wake up signal (WUS) from the terminal, Transmitting a response signal (acknowledgement) to the WUS to the terminal during the WUS response window; and It is set to perform a connection procedure for the above terminal and the second cell of the above terminal, WUS related information is transmitted from the second base station to the first base station corresponding to the first cell, The above WUS related information includes at least one of carrier frequency information of the second cell, WUS transmission time (occasion) information, WUS format information, and WUS response window setting information, A second base station, characterized in that the first cell corresponds to a cell type for connection and synchronization, and the second cell corresponds to a cell type for data transmission and reception.

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