Method and device for receiving wake-up signal by terminal having wake-up receiver in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. In addition, the present disclosure relates to a method performed by a base station and a terminal in a wireless communication system and proposes a method and a device for transmitting and receiving a wake-up signal (WUS), which may be commonly received regardless of the type of wake-up receiver (WUR).

Description

Method and device for receiving a wake-up signal by a terminal having a wake-up receiver in a wireless communication system

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method, procedure and device for terminals having a wake-up receiver to receive a wake-up signal based on an implementation of the wake-up receiver.

[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] As a result of the development of mobile communication systems and the aforementioned advancements in technology, various services have become available, and methods for effectively providing these services are required, and in particular, methods for reducing power consumption of terminals are required.

[0009] The present disclosure provides a method and device for transmitting a common WUS that can be received regardless of the type of wake-up receiver so as to reduce power consumption of a terminal having a wake-up receiver (WUR) in a wireless communication system.

[0010] According to one embodiment of the present disclosure for solving the above problem, a method performed by a terminal in a communication system includes the steps of: receiving a wake up signal (WUS) transmitted from a base station; obtaining WUS information based on the received WUS; and performing a wake up of a main radio receiver or maintaining a sleep mode of the main radio based on the WUS information, wherein the WUS is for an on-off keying (OOK) based wake up receiver (WUR) and an orthogonal frequency division multiplexing (OFDM) based WUR.

[0011] Manchester coding may be applied to the WUS, and one or M OOK pulses of the WUS may be included within an OFDM symbol interval, where M may include 2 and 4. In addition, the WUS is based on a specific OFDM sequence within a pulse time unit corresponding to an on pulse, and the specific OFDM sequence may be set by the base station or may be one sequence from among a set of OFDM sequences.

[0012] In addition, in a method performed by a base station in a communication system, the method comprises: a step of determining whether WUS information should be transmitted to a terminal through a WUS (wake up signal); and a step of transmitting a WUS (wake up signal) corresponding to the WUS information to the terminal when the WUS should be transmitted, wherein the WUS information is related to whether to perform a wake-up of a main radio receiver of the terminal or to maintain a sleep mode of the main radio, and the WUS is characterized in that it is for an OOK (on-off keying) based wake-up receiver (WUR) and an OFDM (orthogonal frequency division multiplexing) based WUR.

[0013] In addition, in a terminal of a communication system, a transmitter / receiver unit; and a control unit configured to receive a WUS (wake up signal) transmitted from a base station, acquire WUS information based on the received WUS, and perform wake-up of a main radio receiver or maintain a sleep mode of the main radio based on the WUS information, wherein the WUS is for an on-off keying (OOK)-based wake-up receiver (WUR) and an orthogonal frequency division multiplexing (OFDM)-based WUR.

[0014] In addition, in a base station of a communication system, a transmitter / receiver unit; and a control unit configured to determine whether WUS information should be transmitted to a terminal through a WUS (wake up signal), and, if the WUS should be transmitted, to transmit a WUS (wake up signal) corresponding to the WUS information to the terminal, wherein the WUS information is related to whether to perform a wake-up of a main radio receiver of the terminal or to maintain a sleep mode of the main radio, and the WUS is for an OOK (on-off keying) based wake-up receiver (WUR) and an OFDM (orthogonal frequency division multiplexing) based WUR.

[0015] The present disclosure provides a method and device for transmitting a common WUS that can be received regardless of the type of WUR so as to reduce power consumption of a terminal by using WUS and WUR, and the terminal can receive the common WUS regardless of the type of WUR it has.

[0016] Figure 1 is a diagram showing an example of the basic structure of a time-frequency resource domain of a wireless communication system.

[0017] FIG. 2 is a diagram showing an example of a time domain mapping structure and beam sweeping operation of a synchronization signal of a wireless communication system.

[0018] Figure 3 is a diagram showing an example of a random access procedure of a wireless communication system.

[0019] Figure 4 is a diagram showing an example of a procedure in which a terminal of a wireless communication system reports terminal capability information to a base station.

[0020] FIG. 5 is a diagram illustrating an example of an operation in which a base station instructs a terminal with WUR to switch to the main radio state through WUS.

[0021] Figure 6 is a drawing showing the structure of a WUS transmitter and an example of a WUS transmission process.

[0022] Figure 7 is a drawing showing the structure of a WUS receiver (or WUR) and an example of a WUS receiving process.

[0023] Figure 8 is a drawing showing the structure of a WUS receiver and another example of a WUS receiving process.

[0024] FIG. 9 is a diagram illustrating how each receiver receives information when there are wake-up receivers simultaneously receiving signals in different ways.

[0025] FIG. 10 is a diagram illustrating an example of the relationship between the OFDM symbol used in the existing system and the pulse time unit of the WUS when the base station transmits the WUS.

[0026] Fig. 11 is a diagram illustrating an example of a method for transmitting and receiving the same information regardless of the WUR type without considering the position information of the on pulse in the standard time unit.

[0027] FIG. 12 is a diagram illustrating an example of a method for transmitting and receiving the same information regardless of the WUR type by utilizing the position information of the on pulse in a reference time unit when multiple OFDM sequences are set for WUS transmission.

[0028] FIG. 13a is a diagram illustrating an example of the operation of a terminal receiving a common wake-up signal (WUS).

[0029] FIG. 13b is a diagram illustrating an example of the operation of a terminal receiving a common wake-up signal (WUS).

[0030] Figure 14 is a diagram illustrating an example of the operation of a base station transmitting a common wake-up signal.

[0031] FIG. 15 is a block diagram illustrating an example of a structure of a terminal according to one embodiment of the present disclosure.

[0032] FIG. 16 is a block diagram illustrating an example of the structure of a base station according to one embodiment of the present disclosure.

[0033] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings. Furthermore, detailed descriptions of known 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 their functions in 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 overall content of this specification.

[0034] 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 disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure of the present disclosure is complete and to fully inform those skilled in the art of the scope of the invention, and the present disclosure is defined only by the scope of the claims. Like reference numerals designate like elements throughout the specification.

[0035] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings 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 flowchart 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 flowchart 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).

[0036] 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.

[0037] Here, the term '~ unit' used in this embodiment means software or hardware components such as FPGA (field programmable gate array) or ASIC (application specific integrated circuit), 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 or may be configured to play one or more processors. Therefore, as an example, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions 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.

[0038] In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Hereinafter, embodiments of the present disclosure will be described with reference to the attached drawings.

[0039] The terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc. are provided as examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0040] In the following description, the terms "physical channel" and "signal" may be used interchangeably with data or control signals. For example, while PDSCH (physical downlink shared channel) refers to a physical channel through which data is transmitted, PDSCH may also be used to refer to data. That is, in the present disclosure, the expression "transmitting a physical channel" may be interpreted equivalently to the expression "transmitting data or a signal through a physical channel."

[0041] Hereinafter, in the present disclosure, upper signaling refers to a signal transmission method in which a base station transmits a signal to a terminal using a downlink data channel of the physical layer, or a terminal transmits a signal to a base station using an uplink data channel of the physical layer. Upper signaling can be understood as radio resource control (RRC) signaling or a media access control (MAC) control element (CE).

[0042] For convenience of explanation, this disclosure uses terms and names defined in the 3GPP NR (New Radio, a 5th generation mobile communications standard) standards. However, this disclosure is not limited to these terms and names and can be equally applied to systems conforming to other standards. Furthermore, the term "terminal" can refer to not only mobile phones, smartphones, IoT devices, and sensors, but also other wireless communication devices.

[0043] Hereinafter, a base station is an entity that performs resource allocation of a terminal, and may be at least one of a gNode B, a gNB, an eNode B, an eNB, 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. Of course, the present invention is not limited to the above examples. In the description of the present disclosure below, uplink (UL) may refer to a wireless link through which a terminal transmits data or a control signal to a base station, and downlink (DL) may refer to a wireless link through which a base station transmits data or a control signal to a terminal.

[0044] Hereinafter, A / B can be understood as A or / and B.

[0045] To handle the explosive growth in mobile data traffic, 5G (5G), the next-generation communication system after LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)) and LTE-A (LTE-Advanced or E-UTRA Evolution), is being developed. thThe initial standards for the 5G (New Radio Access Technology Generation) system or New Radio access technology (NR) have been completed. While existing mobile communication systems have focused on conventional voice / data communications, the 5G system aims to satisfy various services and requirements, such as the enhanced Mobile BroadBand (eMBB) service for improving existing voice / data communications, the Ultra-Reliable and Low Latency Communication (URLLC) service for high reliability / ultra-low latency, and the massive Machine Type Communication (MTC) service for supporting massive machine-to-machine communications.

[0046] While the transmission bandwidth of existing LTE and LTE-A systems per single carrier is limited to a maximum of 20MHz, the 5G system aims to provide ultra-high-speed data services of up to several Gbps by utilizing an ultra-wide bandwidth that is much wider than this. Accordingly, the 5G system is considering ultra-high frequency bands from several GHz up to 100 GHz as candidate frequencies, where securing ultra-wide bandwidth frequencies is relatively easy. Additionally, it is possible to secure wide bandwidth frequencies for the 5G system through frequency reallocation or allocation among frequency bands included in the hundreds of MHz to several GHz used in existing mobile communication systems.

[0047] Radio waves in the ultra-high frequency band are sometimes called millimeter waves (mmWave) because their wavelengths are on the order of millimeters. However, in the ultra-high frequency band, the path loss of radio waves increases in proportion to the frequency band, reducing the coverage of mobile communication systems.

[0048] In order to overcome the disadvantage of reduced coverage in the above ultra-high frequency band, beamforming technology is applied, which uses multiple antennas to concentrate the radiated energy of radio waves to a predetermined target point and increase the transmission distance of radio waves. That is, a signal to which the beamforming technology is applied has a relatively narrow beam width of the signal, and the radiated energy is concentrated within the narrowed beam width, thereby increasing the transmission distance. The beamforming technology can be applied to both the transmitter and the receiver. In addition to the effect of increasing coverage, the beamforming technology has the effect of reducing interference in areas other than the beamforming direction. In order for the beamforming technology to operate properly, accurate measurement and feedback methods of the transmission / reception beams are required. The beamforming technology can be applied to a control channel or data channel that corresponds one-to-one between a predetermined terminal and a base station. Additionally, beamforming technology can be applied to common signals transmitted by a base station to multiple terminals within a system, such as synchronization signals, physical broadcast channels (PBCH), control channels for transmitting system information (or system information block, SIB), and data channels, to increase coverage. When beamforming technology is applied to common signals, beam sweeping technology, which transmits signals by changing the beam direction, is additionally applied so that the common signal can reach terminals located at any location within a cell.

[0049] Another requirement for 5G systems is ultra-low latency services, with transmission delays of approximately 1 ms between transmitters and receivers. One way to reduce transmission delay is to design a frame structure based on a shorter transmission time interval (TTI) than in LTE and LTE-A. A TTI is the basic unit of time for scheduling, and the TTI of existing LTE and LTE-A systems is 1 ms, which corresponds to the length of one subframe. For example, to meet the requirements for ultra-low latency services in 5G systems, shorter TTIs such as 0.5 ms, 0.25 ms, and 0.125 ms are possible, which are shorter than those of existing LTE and LTE-A systems.

[0050] Figure 1 is a diagram illustrating an example of the basic structure of the time-frequency resource domain of a wireless communication system. Figure 1 illustrates the basic structure of the time-frequency resource domain, which is the wireless resource domain through which data or control channels of a 5G system are transmitted.

[0051] Referring to Figure 1, the horizontal axis in Figure 1 represents the time domain and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain of the 5G system is an OFDM (orthogonal frequency division multiplexing) symbol. (102) symbols are grouped together to form one slot (106), A plurality of slots can be grouped to form a subframe (105). The length of the subframe is 1.0 ms, and 10 subframes can be grouped to form a 10 ms frame (114). The minimum transmission unit in the frequency domain is a subcarrier, and the bandwidth of the entire system transmission bandwidth is a total of N BW It can be composed of (104) subcarriers.

[0052] The basic unit of resources in the time-frequency domain is a resource element (RE) (112), which can be represented by an OFDM symbol index and a subcarrier index. A resource block (RB or physical resource block, PRB) in the frequency domain It can be defined as (110) consecutive subcarriers. In 5G systems. = 12, and the data rate can increase in proportion to the number of RBs scheduled to the terminal.

[0053] In a 5G system, a base station can map data in RB units and perform scheduling on RBs, which typically constitute a slot for a given terminal. That is, in a 5G system, the basic time unit for scheduling may be a slot, and the basic frequency unit for scheduling may be an RB.

[0054] Number of OFDM symbols It is determined by the length of the cyclic prefix (CP) added to each symbol to prevent interference between symbols. For example, if normal CP is applied, = 14, when extended CP is applied = 12. Extended CP can be applied to systems with relatively long transmission distances compared to general CP, allowing for maintaining orthogonality between symbols. In the case of general CP, since the ratio of CP length to symbol length is maintained at a constant value, the overhead due to CP can be maintained constant regardless of the subcarrier spacing. That is, if the subcarrier spacing is small, the symbol length becomes longer, and thus the CP length can also become longer. Conversely, if the subcarrier spacing is large, the symbol length becomes shorter, and thus the CP length can be reduced. The symbol length and CP length can be inversely proportional to the subcarrier spacing.

[0055] In 5G systems, various frame structures can be supported by adjusting the subcarrier spacing to meet diverse services and requirements. For example,

[0056] - From the perspective of the operating frequency band, the larger the subcarrier spacing, the more advantageous it is for recovering phase noise in the high-frequency band.

[0057] - From a transmission time perspective, a large subcarrier spacing shortens the symbol length in the time domain, and consequently, the slot length shortens, which is advantageous for supporting ultra-low delay services such as URLLC.

[0058] - From a cell size perspective, a longer CP length allows for larger cells to be supported, so a smaller subcarrier spacing allows for relatively larger cells to be supported. In mobile communications, a cell is a concept that refers to the area covered by a single base station.

[0059] The above subcarrier spacing, CP length, etc. are essential information for OFDM transmission and reception. For smooth transmission and reception, the base station and terminal must recognize the subcarrier spacing, CP length, etc. as common values. Table 1 shows the relationship between the subcarrier spacing configuration (μ), subcarrier spacing (Δf), and CP length supported in the 5G system.

[0060] μΔf = 2 μ ·15 [kHz]Cyclic prefix015Normal130Normal260Normal, Extended3120Normal4240Normal

[0061] Table 2 shows the number of symbols per slot for each subcarrier spacing setting (μ) for the general CP. ), number of slots per frame ( ), number of slots per subframe ( ) is indicated.

[0062] μ 01410111420221440431480841416016

[0063] Table 3 shows the number of symbols per slot for each subcarrier spacing setting (μ) for the extended CP. ), number of slots per frame ( ), number of slots per subframe ( ) is indicated.

[0064] μ 212404

[0065] In the early stages of the introduction of the 5G system, at least coexistence or dual-mode operation with existing LTE or / and LTE-A (hereinafter referred to as LTE / LTE-A) systems is expected. This allows the existing LTE / LTE-A to provide stable system operation to terminals, while the 5G system can play a role in providing improved services to terminals. Therefore, the frame structure of the 5G system needs to include at least the frame structure or essential parameter set of LTE / LTE-A (subcarrier spacing = 15 kHz). For example, comparing a frame structure with a subcarrier spacing setting of μ=0 (hereinafter referred to as frame structure A) and a frame structure with a subcarrier spacing setting of μ=1 (hereinafter referred to as frame structure B), frame structure B shows that the subcarrier spacing and RB size are twice as large as frame structure A, and the slot length and symbol length are twice as small. In frame structure B, two slots can form one subframe, and 20 subframes can form one frame.

[0066] Generalizing the frame structure of a 5G system provides high scalability by ensuring that essential parameters—subcarrier spacing, CP length, and slot length—have integer multiple relationships for each frame structure. Furthermore, a fixed-length subframe of 1 ms can be defined to represent a reference time unit independent of the frame structure.

[0067] The frame structure can be applied to various scenarios. From the perspective of cell size, the longer the CP length, the larger the cell can be supported, so frame structure A can support relatively larger cells than frame structure B. From the perspective of operating frequency band, the larger the subcarrier spacing, the more advantageous it is for phase noise recovery in the high-frequency band, so frame structure B can support relatively higher operating frequencies than frame structure A. From the perspective of service, the shorter the slot length, which is the basic time unit of scheduling, the more advantageous it is for supporting ultra-low-latency services such as URLLC, so frame structure B can be relatively more suitable for URLLC services than frame structure A.

[0068] In the initial access phase when a terminal first accesses the system, the terminal can synchronize downlink time and frequency from a synchronization signal transmitted by a base station through cell search and obtain a cell identifier (cell ID). Then, the terminal can receive a physical broadcast channel (PBCH) using the obtained cell ID and obtain a master information block (MIB), which is essential system information, from the PBCH. Additionally, the terminal can obtain cell-common transmission and reception-related control information by receiving system information transmitted by the base station. The cell-common transmission and reception-related control information may include random access-related control information, paging-related control information, and common control information for various physical channels.

[0069] The synchronization signal serves as a reference signal for cell search, and subcarrier spacing can be applied to suit channel conditions such as phase noise for each frequency band. For data channels or control channels, as described above, different subcarrier spacings can be applied depending on the service type to support various services.

[0070] FIG. 2 is a diagram showing an example of a time domain mapping structure and beam sweeping operation of a synchronization signal of a wireless communication system.

[0071] For the purpose of explanation, the following components may be defined, although they are not limited to the examples below.

[0072] - PSS (primary synchronization signal): This signal serves as the basis for DL ​​time / frequency synchronization and provides some cell ID information.

[0073] - SSS (secondary synchronization signal): Serves as a reference for DL ​​time / frequency synchronization and provides some remaining information, including the cell ID. Additionally, it can serve as a reference signal for PBCH demodulation.

[0074] - PBCH: Provides MIB, essential system information required for transmission and reception of data and control channels of the terminal. Essential system information may include search space-related control information indicating radio resource mapping information for the control channel, scheduling control information for a separate data channel transmitting system information, and SFN (system frame number), a frame-level index that serves as a timing reference.

[0075] - SS / PBCH block (synchronization signal / PBCH block or SSB): An SS / PBCH block consists of N OFDM symbols and is a combination of PSS, SSS, PBCH, etc. In a system 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). The L SS / PBCH blocks are periodically repeated in units of a predetermined period P. The period P can be notified to the terminal through signaling by the base station. If there is no separate signaling for the period P, the terminal applies a pre-agreed default value.

[0076] Referring to FIG. 2, FIG. 2 illustrates an example in which beam sweeping is applied to SS / PBCH block units over time. In the example of FIG. 2, terminal 1 (205) can receive an SS / PBCH block using a beam radiated in the direction of #d0 (203) by beamforming applied to SS / PBCH block #0 at time t1 (201). In addition, terminal 2 (206) can receive an SS / PBCH block using a beam radiated in the direction of #d4 (204) by beamforming applied to SS / PBCH block #4 at time t2 (202). The terminal can obtain an optimal synchronization signal through a beam radiated from the base station in the direction where the terminal is located. For example, terminal 1 (205) 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.

[0077] In addition to the initial connection procedure, the UE may also receive SS / PBCH blocks to determine whether the radio link quality of the current cell is maintained at a certain level. Furthermore, during a handover procedure, in which the UE moves from the current cell to a neighboring cell, the UE 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.

[0078] After the terminal acquires MIB and system information from the base station through the initial access procedure, the terminal can perform a random access procedure to transition the link with the base station to a connected state (or RRC_CONNECTED state). Upon completion of the random access procedure, the terminal transitions to the connected state, enabling one-to-one communication between the base station and the terminal. The random access procedure is described in detail below with reference to FIG. 3.

[0079] Fig. 3 is a diagram showing an example of a random access procedure of a wireless communication system.

[0080] Referring to FIG. 3, as a first step (310) of the random access procedure, a terminal may transmit a random access preamble to a base station. The random access preamble, which is the first transmission message of the terminal in the random access procedure, may be referred to as message 1. The base station may measure a transmission delay value between the terminal and the base station from the random access preamble and synchronize uplink. At this time, the terminal may arbitrarily select which random access preamble to use within a random access preamble set given in advance by system information. In addition, the initial transmission power of the random access preamble may be determined according to the path loss between the terminal and the base station measured by the terminal. In addition, the terminal may determine the transmission beam direction of the random access preamble from the synchronization signal received from the base station and transmit the random access preamble.

[0081] In the second step (320), the base station may transmit an uplink transmission timing adjustment command to the terminal based on the transmission delay value measured from the random access preamble received in the first step (310). The message transmitted in the second step may be referred to as a random access response (RAR) or message 2. In addition, the base station may transmit an uplink resource and power control command to be used by the terminal as scheduling information. The scheduling information may include control information for the uplink transmission beam of the terminal.

[0082] If the terminal fails to receive RAR, which is scheduling information for message 3, from the base station within a predetermined time period in the second step (320), the first step (310) can be performed again. If the first step (310) is performed again, the terminal can increase the probability of the base station receiving the random access preamble by transmitting it while increasing the transmission power of the random access preamble by a predetermined step (power ramping).

[0083] In the third step (330), the terminal can transmit uplink data (message 3) including its terminal identifier to the base station through an uplink data channel (physical uplink shared channel, PUSCH) using the uplink resources allocated in the second step (320). The transmission timing of the uplink data channel for transmitting Message 3 may follow the timing control command received from the base station in the second step (320). In addition, the transmission power of the uplink data channel for transmitting Message 3 may be determined in consideration of the power control command received from the base station in the second step (320) and the power ramping value of the random access preamble. The uplink data channel for transmitting Message 3 may mean the first uplink data signal that the terminal transmits to the base station after transmitting the random access preamble.

[0084] In step 4 (340), if the base station determines that the terminal has performed random access without collision with other terminals, the base station can transmit data (message 4) including the identifier of the terminal that transmitted uplink data in step 3 (330) to the terminal. If the terminal receives the signal transmitted by the base station in step 4 (340) from the base station, the terminal can determine that the random access has been successful. In addition, the terminal can transmit HARQ-ACK information indicating whether message 4 was successfully received to the base station through an uplink control channel (physical uplink control channel, PUCCH).

[0085] If the data transmitted by the terminal in step 3 (330) collides with data from another terminal, causing the base station to fail to receive a data signal from the terminal, the base station may not transmit any more data to the terminal. Accordingly, if the terminal fails to receive the data transmitted from the base station in step 4 (340) within a certain period of time, it may determine that the random access procedure has failed and may restart from step 1 (310).

[0086] Upon successful completion of the random access procedure, the terminal transitions to a connected state, enabling one-to-one communication between the base station and the terminal. The base station receives UE capability information from the connected terminal and can adjust scheduling based on the UE capability information. Through UE capability information, the terminal can inform the base station whether it supports a given function and the maximum allowable value of the function supported by the terminal. Therefore, the UE capability information reported by each terminal to the base station may have different values ​​for each terminal.

[0087] For example, a terminal may report UE capability information including at least a portion of the following control information to a base station as UE capability information, although the present invention is not limited to the following examples.

[0088] - Control information related to frequency bands supported by the terminal

[0089] - Control information related to channel bandwidth supported by the terminal

[0090] - Control information related to the maximum modulation method supported by the terminal

[0091] - Control information related to the maximum number of beams supported by the terminal

[0092] - Control information related to the maximum number of layers supported by the terminal

[0093] - Control information related to CSI (channel state information) reporting supported by the terminal

[0094] - Control information on whether the terminal supports frequency hopping

[0095] - Bandwidth-related control information when supporting carrier aggregation (CA)

[0096] - Control information on whether cross carrier scheduling is supported when carrier aggregation is supported.

[0097] Figure 4 is a diagram showing an example of a procedure in which a terminal of a wireless communication system reports terminal capability information to a base station.

[0098] Referring to FIG. 4, at step 410, the base station (402) can transmit a UE capability information request message to the terminal (401). In response to the base station's request for UE capability information, the terminal transmits UE capability information to the base station at step 420.

[0099] Through the aforementioned process, a terminal connected to a base station is in the RRC_CONNECTED state and can perform one-to-one communication. Conversely, a terminal that is not connected is in the RRC_IDLE state. The operation of a terminal in the RRC_IDLE state can be distinguished as follows. Of course, the following examples are not limited.

[0100] - Operates a terminal-specific DRX (discontinuous reception) cycle set by the upper layer.

[0101] - Action to receive paging messages from the core network

[0102] - Obtain system information

[0103] - Measurement operations related to surrounding cells and cell reselection

[0104] In 5G systems, a new terminal state called RRC_INACTIVE has been defined to reduce the energy and time consumed during initial access. In addition to the actions performed by RRC_IDLE terminals, RRC_INACTIVE terminals can perform the following actions. Of course, these actions are not limited to the examples below.

[0105] - Storage of AS (access stratum) information required for cell access

[0106] - Terminal-specific DRX cycle operation set by the RRC layer

[0107] - Setting up and periodically updating RNA (RAN (radio access network)-based notification area) that can be utilized during handover by the RRC layer

[0108] - Monitoring RAN-based paging messages transmitted via I-RNTI (inactive radio network temporary identifier)

[0109] The following describes a scheduling method in which a base station transmits downlink data to a terminal or instructs the terminal to transmit uplink data.

[0110] Downlink control information (DCI) is control information transmitted from a base station to a terminal via the downlink. It may include downlink data scheduling information or uplink data scheduling information for a given terminal. Typically, the base station independently channel-codes DCI for each terminal and then transmits it to each terminal via the physical downlink control channel (PDCCH).

[0111] The base station can operate by applying a predetermined DCI format according to the purpose, such as whether it is scheduling information for downlink data (downlink assignment), scheduling information for uplink data (uplink grant), or DCI for power control, for the terminal to be scheduled.

[0112] A base station can transmit downlink data to a terminal via the PDSCH, a physical channel for downlink data transmission. Scheduling information, such as the specific mapping location in the time and frequency domains of the PDSCH, modulation scheme, HARQ-related control information, and power control information, can be provided by the base station to the terminal via DCI related to downlink data scheduling information among the DCIs transmitted via the PDCCH.

[0113] A terminal can transmit uplink data to a base station via the PUSCH, a physical channel for uplink data transmission. Scheduling information, such as the specific mapping location in the time and frequency domains of the PUSCH, modulation scheme, HARQ-related control information, and power control information, can be provided to the terminal by the base station via DCI related to uplink data scheduling information among the DCIs transmitted via the PDCCH.

[0114] The time-frequency resources to which the PDCCH is mapped are called control resource sets (CORESETs). A CORESET can be configured for all or part of the frequency resources of the bandwidth supported by the UE in the frequency domain. In the time domain, it can be configured with one or more OFDM symbols, which can be defined as the CORESET length (control resource set duration). The base station can configure one or more CORESETs to the UE through higher layer signaling (e.g., system information, MIB, RRC signaling). Configuring a CORESET to the UE may mean providing information such as a CORESET identifier, the frequency location of the CORESET, and the symbol length of the CORESET. The information that the base station provides to the UE to configure the CORESET may include at least some of the information included in Table 4.

[0115] ControlResourceSet ::= SEQUENCE {controlResourceSetId ControlResourceSetId,(CORESET identifier)frequencyDomainResources BIT STRING (SIZE (45)),(frequency domain resources)duration INTEGER (1..maxCoReSetDuration),(CORESET length)cce-REG-MappingType CHOICE {(CCE-to-REG mapping type)interleaved SEQUENCE {reg-BundleSize ENUMERATED {n2, n3, n6},(REG bundle size)interleaverSize ENUMERATED {n2, n3, n6},(interleaver size)shiftIndex INTEGER(0..maxNrofPhysicalResourceBlocks-1) OPTIONAL -- Need S(interleaver shift)},nonInterleaved NULL},precoderGranularity ENUMERATED {sameAsREG-bundle, allContiguousRBs},(precoding unit)tci-StatesPDCCH-ToAddList SEQUENCE(SIZE (1..maxNrofTCI-StatesPDCCH)) OF TCI-StateId OPTIONAL, -- Cond NotSIB1-initialBWP(QCL configuration information)tci-StatesPDCCH-ToReleaseList SEQUENCE(SIZE (1..maxNrofTCI-StatesPDCCH)) OF TCI-StateId OPTIONAL, -- Cond NotSIB1-initialBWP(QCL configuration information)tci-PresentInDCI ENUMERATED {enabled} OPTIONAL, -- Need S(QCL indicator configuration information in DCI)pdcch-DMRS-ScramblingID INTEGER (0..65535) OPTIONAL, -- Need S(PDCCH DMRS scrambling identifier)}

[0116] CORESET is in the frequency domain It can be composed of RBs and in the time domain ∈{1,2,3} symbols. NR PDCCH can be composed of one or more CCEs (control channel elements). One CCE can be composed of six REGs (resource element groups), and a REG can be defined as one RB during one OFDM symbol. Within one CORESET, REGs can be indexed in time-first order, starting with REG index 0 from the first OFDM symbol of the CORESET, the lowest RB. Interleaved and non-interleaved methods can be supported as transmission methods for PDCCH. The base station can set whether to interleave or non-interleave transmission for each CORESET to the UE through higher layer signaling. Interleaving can be performed in units of REG bundles. A REG bundle can be defined as a set of one or more REGs.

[0117] The base station can inform the terminal of configuration information such as whether the PDCCH is mapped to which symbol within a slot and the transmission cycle through signaling.

[0118] The search space of the PDCCH is described as follows. The number of CCEs required to transmit the PDCCH can be 1, 2, 4, 8, or 16 depending on the aggregation level (AL), and different numbers of CCEs can be used for link adaptation of the downlink control channel. For example, when AL=L, one downlink control channel can be transmitted through L CCEs. The UE performs blind decoding to detect a signal without knowing information about the downlink control channel, and for this purpose, a search space representing a set of CCEs can be defined. The search space is a set of downlink control channel candidates consisting of CCEs that the UE should attempt to decode on a given aggregation level, and since there are various aggregation levels that create a single bundle with 1, 2, 4, 8, or 16 CCEs, the UE can have multiple search spaces. A search space set can be defined as the set of search spaces at all established aggregation levels.

[0119] Search spaces can be categorized into a common search space (CSS) and a UE-specific search space (USS). A certain group of UEs, or all UEs, can scan the common search space of the PDCCH to receive cell-common control information, such as dynamic scheduling for system information or paging messages. For example, a UE can receive scheduling allocation information for the PDSCH for system information reception by scanning the common search space of the PDCCH. In the case of the common search space, since a certain group of UEs, or all UEs, must receive the PDCCH, it can be defined as a set of pre-arranged CCEs. UE-specific scheduling allocation information for the PDSCH or PUSCH can be received by scanning the UE-specific search space of the PDCCH. The UE-specific search space can be defined UE-specifically as a function of the UE's identity and various system parameters.

[0120] The base station can set the search space configuration information of the PDCCH to the terminal through higher layer signaling (e.g., SIB, MIB, RRC signaling). For example, the base station can set the number of PDCCH candidates in each aggregation level L, the monitoring period for the search space, the monitoring occasion for each symbol within the slot for the search space, the search space type (common search space or terminal-specific search space), the combination of DCI format and RNTI to be monitored in the corresponding search space, the CORESET index to be monitored for the search space, etc. to the terminal. For example, the parameters for the search space for the PDCCH may include information such as that shown in Table 5 below.

[0121] SearchSpace ::= SEQUENCE {searchSpaceId SearchSpaceId,(search space identifier)controlResourceSetId ControlResourceSetId OPTIONAL, -- Cond SetupOnly(CORESET identifier)monitoringSlotPeriodicityAndOffset CHOICE {(monitoring slot period and offset)sl1 NULL,sl2 INTEGER (0..1),sl4 INTEGER (0..3),sl5 INTEGER (0..4),sl8 INTEGER (0..7),sl10 INTEGER (0..9),sl16 INTEGER (0..15),sl20 INTEGER (0..19),sl40 INTEGER (0..39),sl80 INTEGER (0..79),sl160 INTEGER (0..159),sl320 INTEGER (0..319),sl640 INTEGER (0..639),sl1280 INTEGER (0..1279),sl2560 INTEGER (0..2559)} OPTIONAL, -- Cond Setupduration INTEGER (2..2559) OPTIONAL, -- Need R(모니터링 가라)monitoringSymbolsWithinSlot BIT STRING (SIZE (14)) OPTIONAL, -- Cond Setup(슬롘 내 모리스 심보운지)nrofCandidates SEQUENCE {(집성 별별 PDCCH 이리군 수) aggregationLevel1 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel2 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel4 ENUMERATED { n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel8 ENUMERATED { n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel16 ENUMERATED { n0, n1, n2, n3, n4,n5,n6,n8}} OPTIONAL. Need RaggregationLevel4 ENUMERATED {n1, n2} OPTIONAL, -- Need RaggregationLevel8 ENUMERATED {n1, n2} OPTIONAL, -- Need RaggregationLevel16 ENUMERATED {n1, n2} OPTIONAL -- Need R},...} OPTIONAL, -- Need Rdci-Format2-1 SEQUENCE {...} OPTIONAL, -- Need Rdci-Format2-2 SEQUENCE {...} OPTIONAL, -- Need Rdci-Format2-3 SEQUENCE {dummy1 ENUMERATED {sl1, sl2, sl4, sl5, sl8, sl10, sl16, sl20} OPTIONAL, -- Cond Setupdummy2 ENUMERATED {n1, n2},...} OPTIONAL -- Need R},ue-Specific SEQUENCE {(Terminal-Specific Search Space)dci-Formats ENUMERATED {formats0-0-And-1-0, formats0-1-And-1-1},...,}} OPTIONAL -- Cond Setup2}.

[0122] According to the configuration information, the base station may set one or more search space sets for the terminal. According to one embodiment of the present disclosure, the base station may set search space set 1 and search space set 2 for the terminal. In search space set 1, the terminal may be set to monitor DCI format A scrambled with X-RNTI in a common search space, and in search space set 2, the terminal may be set to monitor DCI format B scrambled with Y-RNTI in a terminal-specific search space. According to the configuration information, one or more search space sets may exist in the common search space or the terminal-specific search space. For example, search space set #1 and search space set #2 may be set as common search spaces, and search space set #3 and search space set #4 may be set as terminal-specific search spaces.

[0123] In a common search space, a terminal can monitor the following combinations of DCI formats and RNTIs, although these are not limited to the following examples.

[0124] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI

[0125] - DCI format 2_0 with CRC scrambled by SFI-RNTI

[0126] - DCI format 2_1 with CRC scrambled by INT-RNTI

[0127] - DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

[0128] - DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0129] In a terminal-specific search space, a terminal can monitor the following combinations of DCI formats and RNTIs, although these are not limited to the following examples.

[0130] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0131] - DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0132] The above-mentioned RNTIs may follow the following definitions and uses:

[0133] - C-RNTI (cell RNTI): For terminal-specific PDSCH or PUSCH scheduling purposes.

[0134] - TC-RNTI (temporary cell RNTI): For terminal-specific PDSCH scheduling purposes

[0135] - CS-RNTI (configured scheduling RNTI): Used for terminal-specific PDSCH scheduling that is set semi-statically.

[0136] - RA-RNTI (random access RNTI): Used for PDSCH scheduling in the random access phase.

[0137] - P-RNTI (paging RNTI): Used for scheduling PDSCH where paging is transmitted.

[0138] - SI-RNTI (system information RNTI): Used for scheduling PDSCH where system information is transmitted.

[0139] - INT-RNTI (interruption RNTI): Used to indicate whether pucturing is in progress for PDSCH.

[0140] - TPC-PUSCH-RNTI (transmit power control for PUSCH RNTI): Used to indicate power control commands for PUSCH.

[0141] - TPC-PUCCH-RNTI (transmit power control for PUCCH RNTI): Used to indicate power control commands for PUCCH.

[0142] - TPC-SRS-RNTI (transmit power control for SRS RNTI): Used to indicate power adjustment commands for SRS (sounding reference signal).

[0143] The DCI formats described above can follow the definitions shown in Table 6 below.

[0144] DCI formatUsage0_0Scheduling of PUSCH in one cell0_1Scheduling of PUSCH in one cell1_0Scheduling of PDSCH in one cell1_1Scheduling of PDSCH in one cell2_0Notifying a group of UEs of the slot format2_1Notifying a group of UEs of the PRB(s) and OFDM symbol(s) where UE may assume no transmission is intended for the UE2_2Transmission of TPC commands for PUCCH and PUSCH2_3Transmission of a group of TPC commands for SRS transmissions by one or more UEs

[0145] In a 5G system, the search space of aggregation level L in CORESET p and search space set s can be expressed as in the following mathematical expression 1.

[0146] [Mathematical Formula 1]

[0147]

[0148] - L: Integration level

[0149] - n CI : Carrier Index

[0150] - n CCE,p : Total number of CCEs present in CORESET p

[0151] - : slot index

[0152] - : Number of PDCCH candidates for aggregation level L

[0153] - = 0, ..., -1: PDCCH candidate index of aggregation level L

[0154] - l = 0, ..., L -1

[0155] - , Y p,-1 = nRNTI≠0, A p = 39827 for p mod 3 = 0, A p = 39829 for p mod 3 = 1, A p = 39839 for p mod 3 = 2, D= 65537

[0156] - n RNTI : Terminal identifier

[0157] The value can be 0 for a common search space.

[0158] In the case of a terminal-specific search space, the value may correspond to a value that changes depending on the terminal's identity (C-RNTI or ID set to the terminal by the base station) and the time index.

[0159] As described above, to achieve ultra-high-speed data services reaching several Gbps in 5G systems, ultra-wide bandwidth signal transmission and reception of tens to hundreds of MHz or even several GHz can be supported. Ultra-wide bandwidth signal transmission and reception can be supported through a single component carrier (CC) or through carrier aggregation technology that combines multiple component carriers. When carrier aggregation technology is used, if a mobile communication service provider cannot secure a frequency with sufficient bandwidth for ultra-high-speed data services through a single component carrier, the aggregate frequency bandwidth can be increased by combining individual component carriers with relatively small bandwidths, thereby enabling ultra-high-speed data services.

[0160] 5G systems are designed and developed for a wide range of use cases. In addition to standby time, reliability, and availability, device energy efficiency is crucial in 5G systems. 5G devices require weekly or daily charging, depending on individual usage. Typically, 5G devices consume tens of milliwatts (mW) when idle or inactive, and hundreds of mW when connected. Designing for extended battery life is essential not only for a better user experience but also for improving energy efficiency. Energy efficiency is even more critical for devices without a continuous energy source, such as those using small rechargeable or single coin-cell batteries. Sensors and actuators will be widely deployed for 5G use cases, including monitoring, measurement, and charging. Typically, the batteries for these sensors and actuators are non-rechargeable and will require a battery life of at least several years. Wearables include smartwatches, rings, eHealth devices, and medical monitoring devices, which typically struggle to maintain a battery life of one to two weeks depending on usage.

[0161] One way to reduce power consumption in 5G terminals is to operate in DRX mode. DRX-enabled terminals are activated periodically, transmitting and receiving information only during specific periods. The reduction in power consumption depends on the length of the active period, such as the paging cycle. To meet battery life requirements, it is expected that extended discontinuous reception (eDRX) cycles with higher values ​​will be used.

[0162] However, using eDRX cycles may not be suitable for low-latency services because long battery life relies on long latency. For example, in a fire detection and suppression use case, fire shutters must close and sprinklers must be activated by actuators within 1-2 seconds of a fire being detected by a sensor. Therefore, in latency-critical use cases, the traditionally high-value eDRX cycles may not be able to meet the latency requirements, making eDRX unsuitable.

[0163] 5G terminals need to wake up periodically once per DRX cycle to check if there is data to be received, which can cause unnecessary power consumption during periods without signaling or data traffic. To solve this problem, if the terminal could wake up only when it needs to be activated, such as when there is data that the terminal needs to receive, such as paging information, power consumption could be drastically reduced. This can be achieved by using a wake-up receiver (WUR) that can monitor the wake-up signal (WUS) with ultra-low power, and turning on (or triggering) the main radio (which can be understood as a signal transmission and reception device that can perform data communication using existing NR radio devices or cellular communication) only when data transmission and reception are required.

[0164] FIG. 5 is a diagram illustrating an example of an operation in which a base station instructs a terminal with WUR to switch to the main radio state through WUS.

[0165] Referring to FIG. 5, when a base station transmits a WUS (501) corresponding to ON or OFF to a terminal (UE), the terminal can receive the WUS (501) using a WUR (502). Here, the WUR may be a low power WUR. Depending on whether the received signal is ON or OFF information, the terminal can trigger (503) the main radio (504) in the OFF or ON state to wake it up or turn it off, respectively. In some cases, the terminal may not completely turn off the main radio (504), but may also turn off most of the components of the main radio and set it to a deep sleep state in which only essential components such as an internal clock and memory operate.

[0166] If data traffic (505) to be transmitted from the base station to the terminal occurs and a WUS corresponding to ON is transmitted from the base station to the terminal, the main radio becomes ON (506), and the terminal can receive the data transmitted by the base station through the main radio, not the WUR. Since the power consumption for monitoring the WUS depends on the WUS design and the hardware module of the WUR used for signal detection and processing, it can be expected that the benefits of utilizing WUS and WUR will be maximized, especially for power-sensitive and small form factor devices including IoT use cases (such as industrial sensors and controllers) and wearables.

[0167] When designing a wake-up receiver capable of receiving WUS, various wake-up receivers can be designed based on the waveform or modulation method of the wake-up signal and the corresponding reception method. For example, if the waveform of the WUS is designed using on-off keying (OOK), the terminal (or WUR) can determine the encoded bit information transmitted from the base station through a receiver equipped with an envelope detector that measures the envelope of the signal's reception power. In this case, since information such as the signal's phase is unnecessary in the signal reception process, a phase-locked loop (PLL) for aligning the signal's phase and a fast Fourier transform (FFT) module typically required in OFDM receivers are also not required. Therefore, since the receiver structure is relatively simple, the terminal (or WUR) can operate using low power to receive WUS and reduce the overall power consumption of the terminal. However, due to factors such as attenuation caused by the wireless channel, coverage is limited compared to other channels in existing 5G systems. Furthermore, compared to OFDM-based signals, significant resources must be expended in the time domain to ensure reception performance. In the following description, the receiver that determines transmitted information based on envelope measurements of the signal's reception power is referred to as Low-Power Receiver A (WUR-A).

[0168] Another method is to utilize the existing OFDM-based modulation method with another WUS waveform. The transmitter transmitting the WUS can transmit the WUS in the same way as the existing OFDM-based synchronization signal and reference signal by mapping the sequence corresponding to the WUS information to be transmitted to the subcarrier allocated for WUS transmission in the IFFT (inverse fast Fourier transform) module used in OFDM-based signal transmission. However, the receiver receiving the WUS can determine the presence of WUS reception and the operation of the main radio using a cross-correlator in the time dimension without an FFT module, and depending on the implementation, if the FFT module is installed in the WUR, the above operation can be performed in the frequency dimension through the FFT module. Unlike OOK-based WUS, OFDM-based WUS requires in-phase and quadrature branch (IQ branch) and PLL to receive complex information. However, components with lower performance but lower power consumption than those mounted on the main radio can be used. In addition, other components can be used with relatively low power consumption at the expense of performance, so that the power consumed through them can be reduced compared to the main radio. Moreover, when receiving WUS using a cross-correlator in the time dimension, WUS can be received without an FFT module, which can further reduce power consumption. A receiver that determines transmitted information based on receiving complex signals in the baseband in the time dimension or frequency dimension using IQ branch and PLL is named Low Power Receiver B (WUR-B).

[0169] Assuming that WUR is activated for the same amount of time to receive WUS, the average power required for WUR-B is bound to be relatively higher than that of WUR-A. Therefore, in terms of the overall power reduction gain of the terminal, WUR-A is higher. However, when comparing in terms of WUS reception capability, that is, in terms of coverage, WUR-B has a higher performance than WUR-A. Therefore, when WUR-B is used, WUS transmitted by the base station can be stably received over a wider area. Therefore, depending on the characteristics of the terminal, such as the purpose of use, power reduction gain, and mobility, there are cases where WUR-A is advantageous and cases where WUR-B is advantageous. For example, in the case of IoT devices that require extremely low power consumption by being equipped with a semi-permanent battery, it is advantageous to install WUR-A, whereas in the case of terminals such as smartphones that require stable operation in environments with high mobility, WUR-B is advantageous. As described above, different WURs can be installed according to the characteristics of the terminal.

[0170] Therefore, if a base station supports a WUS that can only be received with either a WUR-A or WUR-B receiver structure, the WUR implementation of the terminal and the benefits that can be obtained are limited. On the other hand, a method in which the base station supports both a WUS that can be received with WUR-A and a WUS that can be received with WUR-B can be considered. However, this has a limitation in that the base station must know which type of WUR is installed in each terminal in order to transmit the WUS corresponding to the WUR of each terminal. If the base station does not know this information, it must transmit both types of WUS to wake up one terminal or one group of terminals. This may result in a separate implementation for transmitting different types of WUS and more resource consumption.

[0171] In other words, from the base station's perspective, transmitting a single type of WUS is more advantageous than generating and transmitting multiple types of WUS. Therefore, considering both the convenience of the base station and the freedom of WUR implementation in the terminal, it is helpful to design the WUS so that both terminals with WUR-A and terminals with WUR-B can receive a single type of WUS.

[0172] Hereinafter, a method for designing a common WUS so that a single WUS transmitted by a base station can be received by terminals equipped with different types of WURs or terminals capable of receiving WUS in other ways, and a procedure for common WUS transmission and reception between the base station and terminals are specifically described through specific examples. In the following description, a WUS that can be received by both WUR-A and WUR-B receivers is referred to as a common WUS or harmonized WUS.

[0173] The base station or terminal described in this disclosure may be replaced by any device designed for the same purpose, transmitting (or receiving) a WUS. For example, the entity transmitting the WUS may be another terminal, and the entity receiving the WUS may also be considered any device that receives the WUS, not just the terminal. Accordingly, the design includes not only a downlink WUS transmitted from a base station to a terminal, but also an uplink WUS transmitted from a terminal to a base station, and a sidelink WUS transmitted from a terminal to another terminal.

[0174] <Example 1>

[0175] A first embodiment of the present disclosure describes methods for a transmitter to transmit a common wake-up signal regardless of the type of wake-up receiver used by a terminal. More specifically, a method for a transmitter to transmit a common wake-up signal so that the same information is received regardless of the type of wake-up receiver used by a terminal is described.

[0176] First, the overall wake-up signal transmission and reception methods are described based on FIGS. 6 to 8.

[0177] Figure 6 is a drawing showing the structure of a WUS transmitter and an example of a WUS transmission process.

[0178] Referring to FIG. 6, in order to transmit a common WUS, the transmitter assigns specific values ​​x to the subcarrier (601) allocated for WUS transmission. m (602) can be considered as a method of transmitting by mapping. At this time, the specific value x m (602) may be a dedicated waveform (609) transmitted in the m-th OFDM symbol that has gone through the WUS transform (608). At this time, the subscript m means the WUS transmitted in the m-th OFDM symbol, and one WUS may be transmitted across one or more OFDM symbols. In addition, channels (or signals) for other purposes may be transmitted together in other subcarriers (603) constituting the carrier in addition to the subcarrier for the WUS, and after the IFFT module (604), the WUS and other channels are transmitted together through a series of processes such as CP insertion (CP insertion, 605), an analog signal conditioning process including conversion to an analog signal (DAC (digital-to-analog convertor) and analog front-end, 606), and signal amplification (power amplifier, 607).

[0179] Figure 7 is a drawing showing the structure of a WUS receiver (or WUR) and an example of a WUS receiving process.

[0180] Referring to Fig. 7, signals unrelated to WUS are removed in the baseband (BB) band-pass filter (BPF) or low-pass filter (LPF) (701) of the receiver, so that WUR receives only signals in the band corresponding to the subcarrier to which WUS is mapped. At this time, the band of the filter is x m This mapped subcarrier contains the frequency band and serves to minimize interference with other signals mapped to surrounding subcarriers. Furthermore, the subcarrier location to which the WUS is mapped can be freely set by the base station, and this information is provided in advance to the WUS receiver.

[0181] After the received signal passes through the baseband BPF or LPF (701), the WUS receiver measures the power size of the received signal through the envelope detector (BB envelope detector, 702). The signal passing through the envelope detector (702) is digitized through a single-bit or multi-bit analog-to-digital convertor (ADC, 703), and in the digital processing process (digital BB processing, 704), the WUS receiver determines which bit information is transmitted according to a specific standard. At this time, if the bit used for digitization is 1 bit, a single-bit ADC is used as the ADC, and if it is 2 or more bits, a multi-bit ADC is used. The higher the bit of the ADC, the more precisely the envelope size can be expressed, which is advantageous in determining information, but the structure of the receiver can become relatively complex.

[0182] The example of Fig. 7 can be viewed as an example of the WUR-A described above because it determines what information is transmitted based on the power value in a specific section of the transmitted signal. At this time, since the phase information of the received signal is unnecessary, the WUS receiver can convert the bandpass signal into a baseband signal through a mixer (705) and a local oscillator (LO) (706) with relatively little power by using an FLL (frequency-locked loop) instead of a PLL. In addition, the receiver can obtain the bandpass signal through an RF BPF and an RF low noise amplifier (LNA). Fig. 7 illustrates an example of a WUS receiver, and specific configurations may be added or omitted. For example, although the drawing adopts a method of directly converting the received signal into a baseband, a method of converting it into an intermediate frequency signal and passing it through a filter in the corresponding band may also be considered.

[0183] Figure 8 is a drawing showing the structure of a WUS receiver and another example of a WUS receiving process.

[0184] Referring to Fig. 8, unlike Fig. 7 in which the WUS receiver is configured with a single branch, the WUS receiver is configured with two branches. The two branches are the I branch (802) and the Q branch (803) for detecting the complex signal of the baseband, respectively. Therefore, Fig. 8 can also be viewed as an example of the WUR-B described above. The LPF (or BPF, 801) and the ADC (804) perform the same functions as in Fig. 7 described above, and the differences are that in the structure of Fig. 8, a multi-bit ADC is typically used, and since the signal of each branch must be received, there are two LPFs (801) and two ADCs (804). The signals input to the I branch (802) and the Q branch (803) can be separated through a PLL, a local oscillator (LO), and a mixer, and since the signal is sensitive to frequency and phase errors when receiving the signal with the structure, the PLL is required.

[0185] Similar to Fig. 7, signals unrelated to WUS are removed by the LPF (801) of the receiver, so that WUR receives only signals in the band corresponding to the subcarrier to which WUS is mapped. At this time, the band of the filter is x m This mapped subcarrier contains the frequency band and serves to minimize interference with other signals mapped to surrounding subcarriers. Furthermore, the subcarrier location to which the WUS is mapped can be freely set by the base station, and this information is provided in advance to the WUS receiver.

[0186] As explained above, in the digital processing process (805), it may be detected whether the WUS to be received has been transmitted through a cross-correlator in the time dimension, or 805 may include an FFT module to detect whether the WUS to be received has been transmitted in the frequency dimension as shown in Fig. 6 x m (602) can also be detected if it has been transmitted. At this time, x mDepending on what value is mapped to (602) and whether WUR knows that value, the structure of the receiver that can receive the signal may vary.

[0187] FIG. 9 is a diagram illustrating how each receiver receives information when there are wake-up receivers simultaneously receiving signals in different ways.

[0188] Referring to Figure 9, when the transmitter wants to transmit a signal '1' in the mth OFDM symbol, m When we want to map an arbitrary value or a specific predefined sequence to and transmit a signal of '0', we assume that 0 is mapped to all subcarriers. When the transmitter wants to transmit bit information of 1001, x is mapped to 4 OFDM symbols. m The WUS waveform in the time dimension may appear as 901. As the WUS passes through the wireless channel, the receiver receives a waveform as 902 due to the effects of attenuation, multipath, etc. At this time, the WUR-A (903) determines the bit information based on the envelope (904) of the received signal. Therefore, x m Even if WUR-A does not know the information about the signal '1', if the signal received has a certain level of power, WUR-A (903) can distinguish whether the information '1' was transmitted or the signal '0' was transmitted.

[0189] Meanwhile, WUR-B(905) is a specific sequence x mapped to a subcarrier. m (602) can be used to determine whether the received information is 1 or 0 based on whether it was transmitted. Therefore, WUR-B (905) is x m Information about (602) or x mWhen this is mapped and goes through the IFFT process, the waveform (906) information in the time dimension must be known to determine whether information corresponding to 1 has been received in the digital processing process (805) of WUR-B. If the waveform that WUR-B wants to detect is not received, WUR-B (905) determines that 0 has been transmitted. At this time, it is assumed that WUR-B (905) knows the reference time unit information, such as when WUS is transmitted from the base station and the reference time unit (907) information in which information of 1 or 0 is transmitted is set in advance, or the reference time unit information is set to a specific value. Therefore, when determining the information received through cross-correlation (908) in the time dimension, WUR-B (905) can determine whether information representing 1 or information representing 0 has been transmitted by determining whether the cross-correlation result of 906 generated by WUR-B (905) and the waveform received during the reference time unit (907) exceeds a threshold. If WUR-B(905) has an FFT module, it determines the information in the frequency dimension.

[0190] That is, when the waveform or information of a signal is defined when transmitting a signal having a specific power and the information is also provided to a terminal, a common WUS can be designed so that both a receiver (903) that determines information by the power value of the received signal and a receiver (905) that determines information by the degree of consistency of the information of the received signal can receive the signal. At this time, the base station transmits the common WUS, and the terminal can selectively implement the WUR operation, such as the operation of WUR-A (903) or WUR-B (905), when receiving the WUS. However, depending on the type of WUR, the same information may be transmitted through the WUS, or the WUS may be designed so that different information is transmitted. In this embodiment, a method of designing a WUS so that the same information is received regardless of the type of WUR is described.

[0191] When determining whether the bit information received in WUR-A and WUR-B is 1 or 0, if no technique including a coding technique is applied, the receiver determines the information based on a preset threshold value. For example, in the case of WUR-A, the envelope of the received signal is compared with the threshold value to determine whether the transmitted information is 1 or 0 for each reference time unit (907), and in the case of WUR-B, the transmitted information is determined by comparing the cross-correlation value of the received signal and 906 with the threshold value. At this time, 906 may be one or multiple, and accordingly, WUR-B may go through the cross-correlation process multiple times during the reference time unit (907) or derive multiple cross-correlation values ​​through multiple cross-correlators.

[0192] However, in a wireless communication environment where the channel is generally changing, it is not easy to set an appropriate threshold value without channel information. In addition, in the case of WUS for WUR-A, since information is determined only by the signal power, the reception capability may be reduced. To solve this problem and transmit signals with high reliability, a technique such as Manchester coding can be considered. Manchester coding is characterized by a change in voltage at the reference time unit (907) in which information is transmitted. For example, to send a signal of 1, a voltage waveform of '10' is generated, and to send a signal of 0, a voltage waveform of '01' is generated. Alternatively, the opposite of the above explanation is possible, where 0 is set to '10' and 1 is set to '01'. Referring to FIG. 9, when Manchester coding is not applied, the transmitted signal has a constant waveform such as 0 or 1 during the reference time unit (907), whereas when Manchester coding is applied, the reference time unit in which information is transmitted is set to 908, and the voltage level of the signal is changed and transmitted during the reference time unit. That is, in the case of Fig. 9, when Manchester coding is not applied, the transmitter transmits bit information of '1001', but when Manchester coding is applied, information of '10' is transmitted.

[0193] Therefore, by using Manchester coding, the reception performance can be improved instead of consuming more time resources when transmitting the same bit information. It is assumed that the terminal or WUR already knows whether the base station has applied Manchester coding. When Manchester coding is applied, the receiver determines whether the signal received during the reference time unit (908) is 1 or 0. Specifically, when Manchester coding is applied so that 1 corresponds to '10' and 0 corresponds to '01', in the case of WUR-A (903), the power of the front and back parts of the received envelope is compared with the midpoint of the reference time unit (908), and if the power of the front part is greater, it is determined as 1, and if the power of the back part is greater, it is determined as 0. In the case of WUR-B (905), the cross-correlation value of the front part and 906 of the reference time unit (908) and the cross-correlation value of the back part and 906 are compared to determine 1 or 0.

[0194] Alternatively, if both the leading and trailing parts of the reference time unit's cross-correlation result values ​​either all exceed a specific threshold or none exceed it, it can be determined that the channel condition is unstable or that no signal that the terminal wants to receive has been transmitted. In this case, if only one of the leading and trailing parts exceeds a specific threshold, it can be determined that information of 1 or 0 has been received. In the following description, the unit in which bit information is transmitted is called the 'reference time unit', and the unit in which a waveform is transmitted in a physical channel is called the 'pulse duration'. That is, when Manchester coding is not applied, the reference time unit and the pulse duration unit are the same, but when Manchester coding is applied as in the example above, the reference time unit is twice the pulse duration unit.

[0195] FIG. 10 is a diagram illustrating an example of the relationship between the OFDM symbol used in the existing system and the pulse time unit of the WUS when the base station transmits the WUS.

[0196] Referring to Fig. 10, both 1010 and 1020 show examples of transmitting a pulse consisting of four '1001'. 1010 shows a case where the pulse time unit (1011) and the length of the OFDM symbol (1012) are different. In other words, this is a case where multiple pulses can be transmitted in one OFDM symbol. To this end, as illustrated in Fig. 6, the transmitted signal must undergo a special process called WUS transform (608) in the time dimension. The transmitter, through 608, generates a set of values ​​in the frequency dimension that allows the WUS waveform (609 or 1013) to be transmitted in a specific mth OFDM symbol to be generated in the time dimension after the IFFT process (604), i.e., x m (602) can be derived. Examples of methods that can perform the 608 process include the FFT, which can be viewed as the inverse of the IFFT, the discrete Fourier transform (DFT), and the least square method. In the following description, the number of pulses transmitted in one OFDM symbol is referred to as K. That is, 1010 illustrates an example where K is 4.

[0197] 1020 illustrates the case where K is 1. In the case where K is 1, as in 1020, 4 OFDM symbols are required for 4 pulses because the OFDM symbol interval and pulse time unit are the same. When transmitting one pulse, x depends on whether an on pulse (1) or an off pulse (0) is transmitted. m (602) determines whether a specific sequence is mapped. Therefore, when transmitting 1, the transmitter maps and transmits a sequence (1021) having a specific power, and when transmitting 0, it does not map any sequence (1022), so that no signal is transmitted in the frequency dimension corresponding to WUS.

[0198] In the above example, if the number of information bits to be transmitted is P and the number of pulses required to transmit one WUS is L, and if Manchester coding is applied, the relationship between L and P can be viewed as 2P=L. The number of OFDM symbols through which the WUS is transmitted is equal to the value obtained by dividing L by K and applying a ceiling function. Alternatively, the pulse time unit is equal to the length of the OFDM symbol divided by K. Using this relationship, the receiver (or terminal) can infer the number of OFDM symbols through which the WUS is transmitted or the pulse time unit value with some given information. The terminal determines the meaning of the received waveform based on the inferred pulse time unit and the number of OFDM symbols, determines the section through which one WUS is transmitted, and decides whether to wake up the main radio based on the information received during the section.

[0199] Regardless of the type of WUR, that is, whether it is WUR-A or WUR-B, transmitting the same information means that if the information received by WUR-A is a signal to wake up terminal (group) a, then WUR-B also receives a signal to wake up terminal (group) a. Alternatively, even if we do not know which terminal (group) is being woken up, if WUR-A determines that the signal does not wake up terminal (group) b, then WUR-B also receives a signal not to wake up terminal (group) b. This operation includes not only wake-up information that wakes up a specific terminal (group), but also all information that can be transmitted via WUS. In other words, the fact that a common WUS transmits the same information means that terminals with the same wake up ID, which is an identifier indicating wake-up information, perform the same operation after receiving the common WUS, regardless of the WUR type. However, the method of receiving the common WUS may differ as described in FIGS. 7 to 9.

[0200] In the following description, for convenience, receiving the same information is described as receiving the same bit information or pulse pattern. For example, when an on / off pulse waveform corresponding to '1001' and one or more predefined or set OFDM sequences corresponding to '1001' are mapped to each pulse and transmitted, WUR-A can determine that '1001' has been received through the on / off pulse waveform, and WUR-B can determine that '1001' has been received through cross-correlation with predefined or set OFDM sequences. That is, the OFDM sequence is information required for WUR-B to receive WUS. At this time, since it is not within the scope of the present disclosure to determine which terminal '1001' wakes up or what additional information it contains, it is not specifically addressed.

[0201] One way to transmit identical information is to generate the on pulse of the WUS based on a single OFDM sequence. Referring to Fig. 9, a WUS with the same OFDM sequence is generated within all on pulses. In addition, all terminals (specifically terminals with WUR-B) receiving the WUS within a cell where the base station transmits a common WUS know only one OFDM sequence information. The information may be defined in the standard, or the base station may select it from among several sequence candidates defined in the standard. The base station (or transmitter) transmits the corresponding OFDM sequence only for the on pulse and does not map any OFDM sequence to the off pulse. Therefore, the WUR-B (605) can store only the information (906) corresponding to a single preset sequence and determine whether the corresponding section is an on pulse or an off pulse during the pulse time unit through cross-correlation or a similar procedure. As illustrated in Fig. 9, if the on pulse means bit information of 1 and the off pulse means bit information of 0, WUR-B (905) can receive bit information of '1001'. Similarly, WUR-A (903) can also determine that '1001' has been received based on the size of each pulse time unit of the envelope of the received signal. At this time, the number of OFDM symbols required to transmit and receive WUS, pulse time unit information, and the number of bits containing information that WUS wants to convey are the same regardless of the type of WUR.

[0202] However, if only one OFDM sequence is used as described above, WUS is designed so that WUR-B can receive only 1 or 0, that is, 1 bit of information, during a pulse time unit. Since WUR-B is more complex in hardware and consumes more power than WUR-A, it is possible to receive more bits during the same time, that is, a pulse time unit or a reference time unit. For example, if one OFDM sequence can transmit 4 bits, WUR-B can receive information that would be received during 4 pulses through 1 on pulse, and by reducing the time it takes to receive the WUS, the power consumption required for WUR-B to receive the WUS can be reduced. In other words, there may be a difference in the time it takes WUR-A to receive the entire WUS and the time it takes WUR-B to receive the entire WUS to obtain the same information, and WUR-B can compensate for its disadvantage in terms of power consumption by that amount.

[0203] The way to transmit 4 bits with one OFDM sequence is to increase the number of candidates for OFDM sequences that can be transmitted during the same pulse time unit to 16. That is, to transmit and receive N bits of information by transmitting one OFDM sequence, 2 N If you assign a value to a specific information when not transmitting an OFDM sequence (or 2 N -1) OFDM sequence information may be defined in the standard and provided to the base station and terminal, or the base station may provide the above information to the terminal. Alternatively, the base station may configure to the terminal which OFDM sequences are valid among all OFDM sequences defined in the standard for WUS transmission. The specific OFDM sequence generation method and the number of OFDM sequences are not covered in this specification.

[0204] The transmitter is set to 2 in one pulse time unit. NWhen trying to transmit information by mapping an appropriate sequence among OFDM sequence candidates, unlike setting a single OFDM sequence candidate, the off pulse does not contain any information. That is, if WUR-B (which can be used interchangeably with the terminal) wants to receive information through the WUS, the WUS must unconditionally include an on pulse, and if the terminal does not know when and how many on pulses will occur in the WUS, not only will it have no effect of reducing the time it takes for WUR-B to receive the WUS, but it will also cause deviations in the WUS reception capability and reduce reliability. Therefore, if multiple OFDM sequence candidates that can be applied to a single on pulse transmission are defined, Manchester coding, in which an on pulse unconditionally appears at every reference time unit, can be applied.

[0205] For example, depending on whether Manchester coding is applied, the terminal can estimate the number of OFDM sequences (or the number of OFDM sequence candidates) used by the base station. For example, if Manchester coding is not applied, the terminal can assume that only one specific sequence will be transmitted even though multiple OFDM sequences are configured, and can receive a WUS in accordance with the case where the WUS on pulse is generated based on the specific OFDM sequence. The specific OFDM sequence can be predetermined, or can be configured by the base station. In addition, if Manchester coding is applied, the terminal can receive a WUS assuming that one OFDM sequence among multiple OFDM sequence candidates has been used.

[0206] Figures 11 and 12 are diagrams describing a method of transmitting and receiving the same information regardless of the WUR type when multiple OFDM sequences are set for WUS transmission. In Figures 11 and 12, P means the number of bits of information to be transmitted through WUS, and when CRC bits are transmitted in addition to WUS information through on / off pulses, P may or may not include the corresponding CRC bits. Information such as whether the number of CRC bits is included in the value of P and the number of CRC bits is specified in advance in the standard or can be set by the base station. In addition, N means the number of bits that the base station transmits and receives during one on pulse time unit. N The number of bits that can be transmitted by mapping one of the OFDM sequence candidates. At this time, N can be a number greater than 1, and as the number of N increases, the time required for WUR-B to receive WUS can be reduced, and when not receiving WUS, the terminal can turn off WUR to further save power.

[0207] Fig. 11 is a diagram illustrating an example of a method for transmitting and receiving the same information regardless of the WUR type without considering the position information of the on pulse in the standard time unit.

[0208] Figure 11 illustrates two examples, 1101 and 1102, where the terminal can perform different operations depending on the set P and N values. Referring to Figure 11, since Manchester coding is applied to transmit WUS, one reference time unit (1103) contains two pulse time units, one of which contains an on pulse.

[0209] In 1101 of FIG. 11, the number of bits (N) that the OFDM sequence transmitted in the on pulse can indicate is 4, which is the same as the number of bits (P) to be transmitted through the WUS. In this way, when N is greater than or equal to P, the transmitter can transmit all bit information that it wants to transmit through the WUS through one on pulse. In the example of 1101, since the transmitter wants to transmit information called '1001' with an on / off pulse pattern, the transmitter transmits the OFDM sequence (1104) corresponding to 1001 within a specific time (1105). In the example, the length of the specific time is a reference time unit, and the number of on pulses at which the OFDM sequence is transmitted (i.e., the reference time unit in which the OFDM sequence is located or the time domain position at which the OFDM sequence is transmitted in the on pulse) can be set by the base station or specified in the standard. Alternatively, as illustrated in example 1101, the OFDM sequence (1104) corresponding to '1001' may be transmitted for all on pulses to allow the terminal to receive the WUS at a desired on pulse position, or the effect of repeated transmission may be achieved by allowing the terminal to receive multiple identical signals to increase the WUS reception capability. Therefore, as illustrated in example 1101, when receiving a WUS, the minimum time required for the terminal to receive the WUS when N is greater than or equal to P (without considering the position of the on pulse) is 1 reference time unit (1105).

[0210] In 1102 of FIG. 11, the number of bits (N) that the OFDM sequence transmitted in the on pulse can indicate is 2, which is smaller than the number of bits (P) that the WUS wants to transmit. In this way, when N is smaller than P, the terminal can determine the information included in the WUS by receiving multiple OFDM sequences. In 1102, OFDM sequences including one WUS information were transmitted during a period corresponding to P / N × (reference time unit) (1106). Specifically, the first OFDM sequence transmitted by the transmitter corresponds to the OFDM sequence (1107) corresponding to the first 2 bits '10' of the WUS, and the second OFDM sequence corresponds to the OFDM sequence (1108) corresponding to the subsequent 2 bits '01' of the WUS.

[0211] However, the mapping order of the bit information indicated by the OFDM sequence and the bit information of the WUS may vary depending on the method specified in the settings or standards. That is, the two bits indicated by the first OFDM sequence (1107) and the two bits indicated by the second OFDM sequence (1108) may be mapped not to the first and second bits that the transmitter intends to transmit, respectively, and not to the third and fourth bits that the transmitter intends to transmit (i.e., sequential mapping), but may be mapped in an interleaved form. For example, the two bits indicated by the first OFDM sequence (1107) may be the first and third bits that the transmitter intends to transmit, and the two bits indicated by the second OFDM sequence (1108) may be the second and fourth bits that the transmitter intends to transmit. However, the information related to the interleaved mapping of the corresponding bits must be known by the terminal in advance. The interleaved mapping method can be equally applied not only to 1102 but also to the examples in 1101 and FIG. 12. As illustrated in 1102, OFDM sequences indicating WUS information can be repeatedly transmitted (1109). Whether or not to repeat transmission can be specified in the base station settings or standards, and in case of repeat transmission, the terminal can select the 1106 or 1109 section to receive the WUS, or receive all repeatedly transmitted WUS to increase the WUS reception capability.

[0212] FIG. 12 is a diagram illustrating an example of a method for transmitting and receiving the same information regardless of the WUR type by utilizing the position information of the on pulse in a reference time unit when multiple OFDM sequences are set for WUS transmission.

[0213] Similar to Fig. 11, Fig. 12 may also have cases 1201 and 1202 depending on the relationship between P and N. In addition, Manchester coding may be applied so that on pulses and off pulses may appear at every reference time unit (1203). However, the difference from Fig. 11 is that when WUR-B (or a terminal capable of distinguishing the OFDM sequence transmitted in the on pulse) obtains information of WUS, it also utilizes the position of the on pulse at which the OFDM sequence was transmitted at that time point (1204). Specifically, referring to 1201, WUR-B received an OFDM sequence (1205) indicating information of '00100' at the beginning of the first reference time unit (1204). If the appearance of an on pulse in the half-way portion of the reference time unit 1204 means that information '1' has been transmitted, WUR-B can determine that the entire information that WUS wants to convey is '100100' by combining the information of the received OFDM sequence (00100) and the 1 indicated by the position of the on pulse.

[0214] In Figs. 11 and 12, the WUR-B receiving the designed WUS determines whether a specific OFDM sequence is received during two pulse time units within a reference time unit. In Fig. 11, the information on whether the signal is received in the pulse time unit corresponding to the first half of the reference time unit or the pulse time unit corresponding to the second half was not used to infer the entire WUS information. In contrast, in Fig. 12, the part of the reference time unit in which the signal is received (or the position of the on pulse in the reference time unit) indicates information, and including that information, the WUR-B can infer the entire WUS information.

[0215] Therefore, as shown in 1201, when the position information of the on pulse in the reference time unit is utilized, if the relationship between the number of bits P to be transmitted through the WUS and the number of bits N indicated by the OFDM sequence is such that N is greater than or equal to P-1, the WUR can receive the WUS only in 1 reference time unit (1204). For example, if PPM (pulse position modulation) is utilized instead of Manchester coding, the position information of the on pulse can indicate Y bits (Y>1), and in this case, the terminal can determine the WUS reception time based on the relationship between PY and N. In addition, if N is greater than P-1, this may be the case where some of the information acquired based on the OFDM sequence is used. For example, if the value of P is changeable and the value of P becomes smaller than N-1, some of the set OFDM sequences may not be used during transmission and reception.

[0216] If the section and time point at which a terminal with WUR-B detects a WUS are set to only 1 reference time unit (1204) or repeated transmission is not set, the terminal should not perform a WUS reception operation during the section because the base station may transmit a sequence unrelated to the WUS information, such as transmitting an arbitrary OFDM sequence, in another section (1206) that is not set.

[0217] When the terminal combines the information acquired based on the position of the on pulse within the reference time unit and the information acquired through the OFDM sequence, the order of the information bits may be determined differently from the example described above, and it is assumed that the terminal knows in advance how to combine the bit information. In addition, the method of combining the information bits may be related to the time of receiving the WUS. For example, if a specific OFDM sequence is transmitted in the second reference time unit, the OFDM sequence is '10100', and the information '0' obtained from the position information of the on pulse is inserted into the second position of '10100' to obtain information '100100'.

[0218] 1202 is an example showing when the value of N is less than P-1. Since the number of bits that one OFDM sequence can transmit is small, the terminal must receive the WUS for multiple reference time units (1207), and since the terminal can utilize the position information of the on pulse in one reference time unit, the minimum time that the receiver must receive the WUS is P / (N+1)×(reference time unit)(1207). Referring to 1202, the terminal can obtain the information '10' (or obtain the information '1' and '0') through the position information of the on pulse in the first reference time unit and the second reference time unit, obtain the information '01' through the OFDM sequence (1209) transmitted in the first reference time unit, and obtain the information '00' through the OFDM sequence (1210) transmitted in the second reference time unit. By combining these, the terminal can obtain '100100', and the obtained bits are identical to the WUS transmission bits to be transmitted. If the base station does not perform repeated transmission, the WUR-B does not receive the WUS during the 1208 interval. This is only an example, and it is assumed that the combination order of the information obtained based on the position of each on pulse and the information obtained from each OFDM sequence is set by the base station or specified in the standard and is known to the terminal.

[0219] The specific terms used in the above examples may be changed, and the methods described in the first embodiment may be used in combination with each other.

[0220] <Example 2>

[0221] A second embodiment of the present disclosure describes a method of transmitting a common wake-up signal so as to receive different information depending on the type of the wake-up receiver of the terminal, among methods of transmitting a common wake-up signal regardless of the type of the wake-up receiver of the terminal.

[0222] At least some of the contents of the second embodiment may be combined with at least some of the contents described in the first embodiment, and may also include an overall WUS transmission and reception method.

[0223] According to the first embodiment, WUR-B can obtain more bit information in the same amount of time compared to WUR-A. The first embodiment described a WUS transmission and reception method that can increase the number of bits received per unit time of WUR-B to obtain the same information regardless of the WUR type. The second embodiment describes a method that utilizes the advantages of WUR-B to obtain more information.

[0224] Common information that must be transmitted to both WUR-A and WUR-B is typically the wake-up ID, which indicates which terminal (group) should wake up. However, since individually waking up all terminals within a cell by assigning individual wake-up IDs increases the size of the number of bits (P) to be transmitted via WUS, the base station can wake up terminal groups in groups or subgroups. At this time, the group identifier commonly set for both WUR-A and WUR-B is called the wake-up group ID. The wake-up group ID can be set by the base station or derived by combining a formula specified in the standard and / or a unique terminal ID. In this case, examples of information that can be additionally provided to terminals with WUR-B are as follows. However, at least one of the examples below may be information that is commonly transmitted regardless of the type of WUR, and which information is commonly transmitted and which information can be additionally transmitted only to terminals with WUR-B can be set by the base station or specified in the standard.

[0225] - wake-up subgroup ID: An identifier assigned to terminals with the same group ID so that a smaller number of terminals can form a subgroup.

[0226] - TRS (tracking reference signal) information: Information that informs the terminals that receive WUS among the terminals in RRC_INACTIVE and RRC_IDLE states of the TRS resource set that can be used when the main radio receives a signal after waking up the main radio or as a synchronization signal for WUR-B.

[0227] - short message information: short message information included in PDCCH scrambled with P-RNTI

[0228] - Dedicated paging occasion: Information transmitted when there is a dedicated paging occasion for the terminal (group) other than the section defined in the existing standard when the main radio wakes up due to WUS and receives a paging signal. For example, it may indicate time offset information indicating a dedicated paging occasion earlier than the existing paging occasion, but is not limited to these examples.

[0229] One way for WUR-B to additionally receive other information not described in the examples listed above or as examples is for the base station to map and transmit an OFDM sequence associated with the information in another section (e.g., 1206, 1208 of FIG. 12) where WUS is not transmitted other than the minimum section defined for WUR-B to receive WUS (e.g., 1105, 1106 of FIG. 11 and 1204, 1207 of FIG. 12), and for WUR-B to receive the OFDM sequence associated with the information. For example, in order to indicate TRS information corresponding to '10', the base station can transmit an OFDM sequence corresponding to '10' in a reference time unit immediately following the section in which WUS is transmitted.

[0230] In addition, an example of short message information is described in the above example. After waking up the main radio due to WUS, if the PDCCH scrambled with P-RNTI that the main radio should receive transmits only a short message or includes a short message, the base station can transmit a short message indication and the short message that the terminals should receive by waking up the main radio in the WUS information. The bit information corresponding to the short message is transmitted with the corresponding OFDM sequence, and it is assumed that the terminals know in advance in which section the OFDM sequence corresponding to the short message information will be transmitted. For example, information indicating the presence of a short message (short message indication) is transmitted immediately after the section in which the wake-up information of the main radio (via WUS) is transmitted, and if the short message indication is 1, the bit information corresponding to the short message content can be transmitted in the next section. If the terminal receives the WUS and knows whether it is a short message and its contents, there is no need for the terminal to wake up the main radio to receive the PDCCH transmitting the short message. Therefore, by switching the state of the main radio and skipping the PDCCH reception, it can help terminals with WUR-B, which consumes relatively much power, reduce power consumption.

[0231] For TRS information, the base station can help RRC_INACTIVE or RRC_IDLE terminals easily perform synchronization based on the corresponding TRS by indicating TRS resource information set for other RRC_CONNECTED terminals. Therefore, TRS information may not always be transmitted. In cases where the transmission of additional information is irregular, information corresponding to the field '00' indicating that the information was not transmitted can be transmitted.

[0232] In the case of the wake-up subgroup ID, as described above, the wake-up group ID, which is commonly transmitted regardless of the WUR type, may be transmitted first (via WUS) and the wake-up subgroup ID may be transmitted in another section. Alternatively, if wake-up information for a specific terminal group is transmitted during a specific reference time unit section, the OFDM sequence mapped to the specific reference time section may indicate the sub-group ID. Referring to FIG. 12, for example, assuming that information indicating whether a terminal group with a wake-up group ID of 1 in 1201 wakes up is mapped to the first reference time unit (1204), it may be indicated that group 1 should wake up since the position of the on pulse is located at the front of the reference time unit (i.e., the wake-up group ID can be obtained based on the position of the on pulse). At this time, it can be interpreted to mean that among the terminals of group 1, the terminals with the wake-up subgroup ID of '00100' should wake up through the OFDM sequence transmitted in the on pulse. In the above example, when the number of supported subgroups is 1 and the OFDM sequence mapped to the on pulse is 1, it can be interpreted that the terminal operates in the same way as in the case where only one OFDM sequence mapped to the on pulse is defined in the first embodiment. In addition, in the above example, when the number of supported subgroups is 1 and the OFDM sequence mapped to the on pulse is selected and transmitted among two OFDM sequences depending on whether the information transmitted at the reference time is 1 or 0, the terminal can operate in the same way as in the example where N is 1 in FIG. 11.

[0233] The specific terms used in the above examples may be modified, and the present invention is not limited by the specific examples. According to at least one embodiment of the present disclosure, by transmitting a WUS so that a common WUS can be received regardless of the type of WUR, there is a technical effect of increasing the degree of freedom in the WUS reception method of the terminal while reducing the WUS transmission burden of the base station. At least one method of the first embodiment and / or the second embodiment of the present disclosure may be used in combination with each other.

[0234] <Example 3>

[0235] A third embodiment of the present disclosure describes a method for setting parameters for WUS reception for terminals having different reception methods of WUS that are present or may be present within a cell.

[0236] The parameters described in the third embodiment of the present disclosure are described based on the parameters specified in the first embodiment or / and the second embodiment of the present disclosure, but may also include other parameters according to examples that are not specifically specified.

[0237] The WUR types, WUR-A and WUR-B, specified in the first embodiment and / or the second embodiment of the present disclosure are the same as indicating a terminal (or WUS receiver) that can receive only an OOK signal indicated by an on / off pulse and a terminal that can receive an OFDM sequence mapped to a WUS, respectively. Some terminals are equipped with both WUR-A and WUR-B, and the terminal may select either WUR-A or WUR-B to operate according to its preference, or the base station may configure the terminal to perform a specific operation. Whether a terminal includes a certain WUR, whether an operation of a certain WUR is possible, etc. may be reported by the terminal to the base station as a type of capability of the terminal, or there are cases where the base station transmits a WUS without knowing which terminal has which capability. In the following description, a terminal that can receive only a WUS that can be received by WUR-A is called a WUS-OOK-capable terminal, and a terminal that receives only a WUS that can be received by WUR-B is called a WUS-OFDM-capable terminal. Additionally, a terminal that can perform both WUR-A and WUR-B operations depending on the terminal's preference or the base station's settings is called a WUS-both-capable terminal.

[0238] To support the techniques described in this disclosure, the following information must be set or specified in the specifications for terminals that commonly wish to receive or are likely to receive WUS. The following information may be provided directly or may be combined with other information to enable terminals to indirectly determine the information.

[0239] - Frequency resources where common WUS is transmitted: Information can be set regarding which subcarrier range in a specific band or BWP where WUS is transmitted is mapped to the information representing the WUS. The location in the frequency band as well as the available bandwidth for the WUS are either predefined or set by the base station.

[0240] - Time point at which common WUS is transmitted: Information on the time point at which WUS transmission can start may be provided. The section at which WUS can be transmitted may appear repeatedly, in which case period information (and offset information) is also set. In addition, the time point at which common WUS is transmitted may be determined in units of OFDM symbols, which are basic time units in the 5G system. For example, WUS may be transmitted in the same period (D) as the DRX cycle, and if common WUS is transmitted from the nth OFDM symbol after a specific time has elapsed since WUS transmission activation information was received from the base station, the terminal may perform a WUS reception operation at every period D thereafter. This operation may be repeated until the base station determines that WUS transmission is disabled or the WUS reception capability does not meet a specific criterion.

[0241] - Common WUS pulse time unit (X): This information is the time information that serves as the standard when the WUS determines whether the received pulse is an on pulse or an off pulse, or whether an OFDM sequence has been transmitted within a specific section. When transmitting a WUS, the WUS must be generated and transmitted so that the total power in one pulse time unit has a power higher than a specific value (on pulse) or a power close to 0 (off pulse), so that the receiver can reduce errors in determining whether it is an on pulse or an off pulse. This information can be directly set by the base station among several candidates specified in the specification, or can be determined based on the subcarrier spacing used for the WUS and the number of pulses (K) in one OFDM symbol. For example, if the subcarrier spacing is 15 kHz and K is 1, 14 OFDM symbols including CP are transmitted for 1 ms, and one pulse is transmitted in one OFDM symbol, so the time it takes for one pulse to be transmitted can be viewed as having a pulse time unit of 1 / 14 ms.

[0242] The information can also be expressed as a pulse rate, which is the reciprocal of the pulse time unit. In the above example, the pulse rate is 14 kHz. In another example, when the pulse rate is 30 kHz and K is 2, 28 OFDM symbols including CP are transmitted for 1 ms, and 2 pulses are transmitted in one OFDM symbol, so the pulse rate can be said to be 56 kHz. In this case, the subcarrier spacing used for WUS can be the same as the subcarrier spacing used in the corresponding band or BWP, or a separate subcarrier spacing can be set for WUS.

[0243] - Number of pulses in an OFDM symbol (K): K can be used to determine the pulse time unit or pulse rate of a common WUS, as described in the example above. In addition, by utilizing this information, the terminal can know the position of the CP added to the front of the OFDM symbol after how many pulses have been received. That is, when the terminal first receives a WUS, it ignores the CP of the first OFDM symbol and receives the WUS. After receiving K pulses thereafter, it expects that there will be a CP added to the front of the next OFDM symbol, so it removes the CP part and receives the signal, thereby reducing errors caused by the CP. The base station can set one value from among several candidates for this information, or if no value is provided, it can operate with a default defined value (e.g., K=1). In addition, when K is set to 1 and when K is set to a value greater than or equal to 2, different subcarrier values ​​may be set in association. For example, the pulse time unit X value when the subcarrier spacing is 60 kHz and K=1 and the X value when the subcarrier spacing is 30 kHz and K=2 can be set to be the same, but the position and influence of the CP can be different. Therefore, when the K value changes, information about which subcarrier spacing it is associated with or the change in the subcarrier spacing value can also be provided.

[0244] - The total number of information bits transmitted by the common WUS (P): This information is related to the size of the payload, that is, the information obtained from the WUS. The size of the payload may be specified in the specification or set by the base station. Alternatively, rather than directly setting the payload size, the terminal may infer the total payload size through the values ​​of parameters related to the information included in the common WUS, such as the number of wake-up groups or subgroups, from the base station, thereby estimating the number of information bits. At this time, the total information bits refer to information commonly transmitted to all WUS-OOK-capable terminals, WUS-OFDM-capable terminals, and WUS-both-capable terminals, regardless of the terminal's capability. At this time, if the WUS-OFDM-capable terminal and the WUS-both-capable terminal operating as WUR-B are also set or specified to receive CRC bits, the sum of the payload size and the number of CRC bits is the total number of information bits.

[0245] - Whether Manchester coding is applied: This information is information necessary for the receiver to determine how to determine whether the information is 1 or 0 when receiving the information included in the WUS. In addition, when Manchester coding is applied, since two pulses are used to transmit one information bit, the time period required to receive the entire WUS can be inferred in relation to the values ​​of P and X. For specific details, refer to the first embodiment. In addition, as described in the first embodiment, the methods according to FIGS. 11 and 12 cannot be used if Manchester coding is not applied because it is uncertain when and how much the on pulse occurs. Therefore, depending on whether Manchester coding is applied, the terminal can determine whether the methods of FIGS. 11 and 12 are used or whether only one sequence is used as in the first example of the first embodiment.

[0246] - CRC bit application and length: This information is applied to reduce the probability of false detection of WUS among WUS-OOK-capable terminals or WUS-both-capable terminals operating as WUR-A. When CRC bits are applied, the terminal receives WUS for a longer period by the number of bits.

[0247] - Techniques and related settings for improving the reception performance of WUS, such as repetitive transmission, interleaving transmission, etc.: The information can be applied to increase the coverage of a WUS-OOK-capable terminal or a WUS-both-capable terminal operating as WUR-A and reduce the probability of non-detection of WUS. For example, a WUS-OFDM-capable terminal or a WUS-both-capable terminal operating as WUR-B may not perform repetitive reception or interleaving reception, or a repetitive transmission or interleaving technique may be applied differently to a WUS-OOK-capable terminal or a WUS-both-capable terminal operating as WUR-A and a WUS-OFDM-capable terminal or a WUS-both-capable terminal operating as WUR-B.

[0248] In addition to the information listed above, the following information may be required for WUS-OFDM-capable terminals and WUS-both-capable terminals that operate as WUR-B.

[0249] - The number of information bits (N) that an OFDM sequence can transmit (or indicate): The set of OFDM sequences that can be used for WUS is specified in the standard or can be set by the base station. Alternatively, the base station can directly set a specific subset from the entire set specified in the standard, and the terminal can indirectly infer which sequences are used through the set N value or other parameters. If the terminal knows the N value, it can know for how long a time interval it should receive the WUS depending on whether or not it uses the position information of the on pulse as described in FIGS. 11 and 12. That is, assuming that Manchester coding is applied, if the position information of the on pulse is not used as in FIG. 11, the terminal WUS must be received during the corresponding time, and when using on pulse position information as in Fig. 12, the terminal Therefore, assuming that all CRCs are applied or not applied at all, the WUS reception time can be reduced by N or N+1 times for WUR-B compared to terminals with the same reception capability as WUR-A, which must receive WUS for 2PX time.

[0250] - WUS reception section including the position where the OFDM sequence for the corresponding terminals is mapped among the common WUS: In addition to the method of inferring the WUS reception section through the information N described above, a method of informing the WUS reception section of only the corresponding terminals (or the time and / or frequency resources at which the WUS for specific terminals is transmitted) and allowing the terminal to infer N through this may also be considered. Or / and, information may be obtained as to at which position the WUS for the corresponding terminals is transmitted among the entire section where the common WUS is received. This information may be specified in the standard and / or may be set by the base station. For example, the terminal determines the position where the OFDM sequence for specific terminals is mapped based on the first reference time unit at which the common WUS is transmitted, but the base station may arbitrarily adjust the mapped position by setting a specific offset value. If the value is not set, the offset value may be regarded as 0. Or, as in the example of FIG. 11, the same OFDM sequences may be repeatedly transmitted in the section where the common WUS is transmitted. The base station can turn the function ON / OFF, and if ON / OFF is not set, it performs the default operation specified in the specification.

[0251] - If additional information can be transmitted solely for the terminals, the additional information to be transmitted and the method of receiving that information: If additional information is transmitted, as in the example described in the second embodiment, information regarding when and where that information is transmitted must be provided, either directly or indirectly. The information to be provided may be specified in the standard or configured by the base station; for specific details, refer to the second embodiment.

[0252] In addition to the information described above, all terminals receiving a common WUS must know which wake-up ID and / or wake-up group ID they have, and these IDs are associated with which OFDM sequences the terminal should receive. However, the method for generating an OFDM sequence representing a specific ID and the type of OFDM sequence used (M-sequence, Gold sequence, etc.) are not covered in detail as they are outside the scope of this specification.

[0253] Since the information listed above is directly or indirectly related, not all information is directly configured or predefined by the terminal. Based on the relationships described above, only some information may be directly configured or specified by the base station. Based on the acquired information, the terminal can infer other information. The method by which the terminal infers information is not limited to the examples described above.

[0254] Since the capabilities and RRC states of terminals receiving WUS within a cell are different, the parameter setting methods may vary as follows.

[0255] - Method 1: Assign the same RRC settings regardless of the terminal's capabilities.

[0256] - Method 2: Assign different RRC settings according to the terminal's capabilities.

[0257] - Method 3: Assigning an additional RRC setting set according to the terminal's capabilities.

[0258] For methods 1 and 3, even if the base station does not know the terminal's capabilities, the terminal can perform appropriate operations within the given RRC settings based on its capabilities. Method 2 requires the base station to know the terminal's capabilities in order to configure them, but allows for terminal-specific configuration. Therefore, this method may be considered for terminals receiving WUS in the RRC_CONNECTED state. In other words, even for the same terminal, RRC settings related to WUS can be assigned in different ways depending on the RRC state, and the corresponding settings may represent different values ​​or be configured with different parameter combinations.

[0259] In the case of Method 1, since the same RRC parameter type is set regardless of the terminal's capability, the terminal uses the necessary parameters according to its WUS reception method and ignores the unnecessary parameters.

[0260] In method 3, RRC parameters that are commonly used regardless of the terminal's capability exist in a common set. For example, among the information items described above, information ranging from common WUS monitoring resource information to whether Manchester coding is applied can be included as common information. In addition, information corresponding to each WUS-OOK-capable terminal and WUS-OFDM-capable terminal is included and configured in different sets. The difference from method 2 is that according to method 2, WUS-OOK-capable terminals do not receive information corresponding to WUS-OFDM-capable terminals at all, but in method 3, this information is included in a different set. By setting it this way, a WUS-both-capable terminal can select whether to utilize the information in the configuration set corresponding to the WUS-OOK-capable terminal or the information corresponding to the WUS-OFDM-capable terminal depending on which WUS reception operation it performs. At this time, using the above-described items as an example, the configuration set corresponding to the WUS-OOK-capable terminal may include CRC information and configuration information for techniques such as repeated transmission or interleaving transmission to increase the reception capability of WUS, and the configuration set corresponding to the WUS-OFDM-capable terminal may include, in addition to the information listed above, configuration information for terminals operating as WUR-B among the WUS-OFDM-capable terminals and WUS-both-capable terminals.

[0261] The specific terms used in the above examples may be modified, and the contents of the present disclosure are not limited to the examples described herein. At least one of the methods of the first embodiment, the second embodiment, or the third embodiment of the present disclosure may be used in combination with each other.

[0262] <Example 4>

[0263] The fourth embodiment of the present disclosure describes the procedures of a base station and a terminal when transmitting and receiving a common wake-up signal and the operation procedures of the base station and the terminal after transmitting and receiving the wake-up signal.

[0264] FIG. 13a and FIG. 13b are diagrams illustrating an example of the operation of a terminal receiving a common wake-up signal (WUS).

[0265] Referring to Figure 13, terminals capable of receiving WUS report WUS-related capabilities (1301). However, depending on the RRC status of the terminal, this process may be omitted, and it may be assumed that the base station configures and transmits WUS without knowing the exact WUS-related capabilities of the terminal.

[0266] The terminal acquires WUS configuration information (1302), as described in the third embodiment, for example. Specific information may be configured as system information such as MIB / SIB, and other information may be configured via RRC signaling. While WUS reception may be activated (1303) immediately after WUS configuration is received, WUS reception may also be activated via specific signaling. Whether the base station has activated WUS transmission may be included in the information configured in step 1302.

[0267] Before receiving a common WUS, the terminal determines its own WUS capability (1304). In the case of a WUS-OOK-capable terminal or a WUS-both-capable terminal that performs the same operation as a WUS-OOK-capable terminal, i.e., a terminal that performs WUR-A operation (1305), the terminal receives the WUS throughout the entire section in which the common WUS is transmitted based on the information set in step 1302 (1306).

[0268] Meanwhile, in the case of a WUS-OFDM-capable terminal or a WUS-both-capable terminal that performs the same operation as a WUS-OFDM-capable terminal, i.e., a terminal that performs a WUR-B operation (1307), the relationship between the number of information bits P transmitted through a common WUS and the number of bits N that one OFDM sequence can transmit is determined (1308). Examples of the relationship between P and N according to the definition of P and N and the information mapping method are according to the first to third embodiments. Fig. 13 describes the relationship for determining the relationship between P and N as N < P with reference to the example of Fig. 11.

[0269] If the value of N is less than P, the terminal can receive information corresponding to a common WUS for multiple reference time units because the amount of information that one OFDM sequence can transmit is limited (1314). If N is equal to or greater than P, the terminal receives information corresponding to a common WUS in one reference time unit (1317). However, whether reception is performed in multiple time units or in one time unit may vary depending on whether there is additional information to be transmitted to the terminal operating in WUR-B or whether repeated reception, etc., is set for the terminal, in addition to the relationship between N and P, and may also show different aspects depending on the method by which the WUS transmits information.

[0270] For example, if the y-th bit information constituting the payload of the WUS indicates whether the y-th terminal group is woken up as 1 or 0, terminals capable of receiving WUR-B only need to receive information in one section in which the bit corresponding to their group is transmitted. At this time, if a subgroup is defined for a terminal receiving WUR-B, the sequence transmitted in the section can indicate which subgroup within the group is woken up. If not, only one section among the common WUSs can be received even if only one sequence or two sequences representing 1 and 0 respectively are defined.

[0271] When a terminal receives a WUS through steps 1306, 1314, or 1317, all terminals that received the common WUS determine the information obtained from the WUS (1310, 1315, 1318). Basically, the terminal turns on the main radio to determine whether it should receive specific information. Then, based on the received information, the terminal performs actions such as waking up the main radio or maintaining sleep mode (1311, 1316, 1319). If the terminal remains in sleep mode, the steps after receiving the common WUS, 1306, 1314, or 1317, can be repeated. When instructed via a received WUS to wake up the main radio or perform other actions, the terminal may repeat steps 1306 or 1314 or 1317 after completing the action until the base station or a specific point in time specified in the specification deactivates the base station's WUS transmission (1312, 1320, 1321).

[0272] 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.

[0273] Figure 14 is a diagram illustrating an example of the operation of a base station transmitting a common wake-up signal.

[0274] Referring to Figure 14, the base station receives reports of the WUS reception capabilities of terminals (1401). However, the base station may know the capabilities of all terminals, or there may be terminals that do not know the corresponding capabilities depending on the RRC status of the terminals. For example, the capability of an RRC_IDLE terminal may not be accurately known if there is no record of the terminal having previously connected to the base station, or even if the terminal has previously connected, if the base station does not know whether the terminal is camped within the cell operated by the base station.

[0275] The base station configures WUS information (1402) by considering the RRC status of the terminal, etc. The information and configuration method are specifically described in the third embodiment, which describes examples, and the contents of the present disclosure are not limited to the described examples. The configuration information may include whether the WUS transmission mode is activated, so that the WUS transmission mode may be activated immediately when the configuration information is set, or the WUS transmission mode may be activated through separate signaling (1403). When the WUS transmission mode of the base station is activated, the base station transmits a common WUS at every common WUS transmission time or when there is information to be transmitted via the WUS (1404). If the base station does not wake up any terminal group, the base station may not transmit a WUS.

[0276] After transmitting a common WUS, the base station assumes that all terminals have received the WUS and transmits the channel that the terminal that woke up the main radio should receive (1405). For example, if the base station transmitted a WUS for terminals in RRC_IDLE or RRC_INACTIVE that monitor paging information, the base station transmits a PDCCH scrambled with a P-RNTI at a paging point predefined in the standard. At this time, after the awakened terminals receive a specific channel, there are cases where a response from the terminal is not required, and cases where a response is required. The base station determines whether a response from the terminal is required and whether a response from the terminal has been received (1406).

[0277] If a response from the terminal is not required, process 1407 is performed as in the case of a response. The base station can directly signal the terminal to turn off the main radio and repeat the WUS operation after transmitting and receiving all information transmitted by the base station, or the base station can set when the terminal turns off the main radio and repeats the WUS operation, or the standard can specify that such an operation be performed. If the terminal needs to repeat the WUS reception operation, the base station also repeats the process of transmitting a common WUS and a series of processes thereafter (1408).

[0278] In cases where a response from the terminal is required, for example, when an RRC connection is commanded via paging information, requiring the terminal to transmit a PRACH, the process described above, step 1407 and below, is performed in the same manner. In such cases, the process is repeated until the base station determines to disable WUS transmission (1409) and signals the terminals (1408).

[0279] If a response is required from a terminal but there is no response from the terminal, the base station can retransmit a common WUS or, if a WUS can be transmitted only for terminals that have not responded, transmit the WUS (1410). If a WUS is repeatedly transmitted a certain number of times but there is no response, the terminal may be determined to be unable to connect to the base station transmitting the WUS. If a terminal that has not responded to the WUS performs a fallback operation specified in the preset or standard to wake up the main radio and report to the base station information such as notifying that the WUS was not properly received, the base station can set WUS transmission to be disabled for the terminal or all terminals based on the contents reported by the terminals (1411).

[0280] 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.

[0281] The invention of the present disclosure is not limited by the contents described in the above-described FIGS. 13 and 14, and the contents of FIGS. 13 and 14 can be combined with the first embodiment or / and the second embodiment or / and the third embodiment, and each step of FIGS. 13 and 14 can be omitted, or other steps can be added, or the order can be changed so that the present invention can be performed.

[0282] FIG. 15 is a block diagram illustrating an example of a structure of a terminal according to one embodiment of the present disclosure.

[0283] Referring to FIG. 15, a terminal (1500) may include a transceiver (1501), a control unit (e.g., a processor) (1502), and a storage unit (e.g., a memory, 1503). The transceiver (1501), the control unit (1502), and the storage unit (1503) of the terminal (1500) may operate according to at least one or a combination of methods corresponding to the above-described embodiments. However, the components of the terminal (1500) are not limited to the illustrated example. According to other embodiments, the terminal (1500) may include more or fewer components than the components described above. In addition, in certain cases, the transceiver (1501), the control unit (1502), and the storage unit (1503) may be implemented in the form of a single chip.

[0284] The transceiver (1501) may, according to one embodiment, be composed of a transmitter and a receiver. The transceiver (1501) may transmit and receive signals with a base station. The signals may include control information and data. The transceiver (1501) 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 (1501) may receive a signal through a wireless channel and output the signal to the control unit (1502), and transmit the signal output from the control unit (1502) through the wireless channel.

[0285] The control unit (1502) may control a series of procedures that the terminal (1500) may perform according to the embodiments of the present disclosure described above. For example, the control unit (1502) 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 (1502) may include at least one processor. For example, the control unit (1502) 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).

[0286] The storage unit (1503) can store control information (e.g., setting information for WUS set to the terminal (1500)) or data, and can have an area for storing data required for controlling the control unit (1502) and data generated during control by the control unit (1502).

[0287] Although not shown, the terminal (1500) may further include a WUR. The WUR may be included in the transceiver (1501) or may exist as a separate receiver without being included in the transceiver (1501).

[0288] FIG. 16 is a block diagram illustrating an example of the structure of a base station according to one embodiment of the present disclosure.

[0289] Referring to FIG. 16, a base station (1600) may include a transceiver (1601), a control unit (e.g., a processor) (1602), and a storage unit (e.g., a memory) (1603). The transceiver (1601), the control unit (1602), and the storage unit (1603) of the base station (1600) 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 (1600) are not limited to the illustrated example. According to other embodiments, the base station (1600) may include more or fewer components than the components described above. In addition, in certain cases, the transceiver (1601), the control unit (1602), and the storage unit (1603) may be implemented in the form of a single chip.

[0290] The transceiver (1601) may, according to one embodiment, be composed of a transmitter and a receiver. The transceiver (1601) may transmit and receive signals with a terminal. The signals may include control information and data. The transceiver (1601) 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 (1601) may receive a signal through a wireless channel and output the signal to the control unit (1602), and may transmit a signal output from the control unit (1602) through the wireless channel.

[0291] The control unit (1602) may control a series of procedures so that the base station (1600) can operate according to the embodiments of the present disclosure described above. For example, the control unit (1602) 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 (1602) may include at least one processor. For example, the control unit (1602) 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).

[0292] The storage unit (1603) can store control information (e.g., setting information for WUS), data, control information received from a terminal, or data, and can have an area for storing data required for controlling the control unit (1602) and data generated during control in the control unit (1602).

[0293] In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Even components expressed in plural may be composed of singular elements, or even components expressed in singular may be composed of plural elements.

[0294] While the detailed description of the present invention has described specific embodiments, it is clear that various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. In a method performed by a terminal in a communication system, A step of receiving a WUS (wake up signal) transmitted from a base station; A step of obtaining WUS information based on the received WUS; and A step of performing a wake-up of the main radio receiver or maintaining the sleep mode of the main radio based on the above WUS information is included. A method characterized in that the above WUS is for an on-off keying (OOK) based wake up receiver (WUR) and an orthogonal frequency division multiplexing (OFDM) based WUR.

2. In paragraph 1, A method characterized in that Manchester coding is applied to the above WUS.

3. In paragraph 1, One or M OOK pulses of the WUS are included within the OFDM symbol interval, A method characterized in that the above M comprises 2 and 4.

4. In paragraph 1, The above WUS is based on a specific OFDM sequence within the pulse time unit corresponding to the on pulse, A method characterized in that the specific OFDM sequence is set by the base station or is one of a set of OFDM sequences.

5. In a method performed by a base station in a communication system, A step for determining whether WUS information should be transmitted to the terminal via a WUS (wake up signal); and In case the above WUS needs to be transmitted, a step of transmitting a WUS (wake up signal) corresponding to the WUS information to the terminal is included, The above WUS information is related to whether to perform a wake-up of the main radio receiver of the terminal or to maintain the sleep mode of the main radio. A method characterized in that the above WUS is for an on-off keying (OOK) based wake up receiver (WUR) and an orthogonal frequency division multiplexing (OFDM) based WUR.

6. In paragraph 5, A method characterized in that Manchester coding is applied to the above WUS.

7. In paragraph 5, One or M OOK pulses of the WUS are included within the OFDM symbol interval, A method characterized in that the above M comprises 2 and 4.

8. In paragraph 5, The above WUS is based on a specific OFDM sequence within the pulse time unit corresponding to the on pulse, A method characterized in that the specific OFDM sequence is set by the base station or is one of a set of OFDM sequences.

9. At the terminal of the communication system, Transmitter and receiver; and Receives a WUS (wake up signal) transmitted from a base station, Obtaining WUS information based on the received WUS, and A control unit configured to wake up the main radio receiver or maintain the main radio in a sleep mode based on the above WUS information, A terminal characterized in that the above WUS is for a wake up receiver (WUR) based on OOK (on-off keying) and a WUR based on OFDM (orthogonal frequency division multiplexing).

10. In paragraph 9, A terminal characterized in that Manchester coding is applied to the above WUS.

11. In paragraph 9, One or M OOK pulses of the WUS are included within the OFDM symbol interval, A terminal characterized in that the above M includes 2 and 4.

12. In paragraph 9, The above WUS is based on a specific OFDM sequence within the pulse time unit corresponding to the on pulse, A terminal, characterized in that the specific OFDM sequence is set by the base station or is one of a set of OFDM sequences.

13. In the base station of the communication system, Transmitter and receiver; and Determine whether WUS information should be transmitted to the terminal via WUS (wake up signal), and When the above WUS needs to be transmitted, the terminal includes a control unit set to transmit a WUS (wake up signal) corresponding to the WUS information, The above WUS information is related to whether to perform a wake-up of the main radio receiver of the terminal or to maintain the sleep mode of the main radio. A base station characterized in that the above WUS is for an on-off keying (OOK) based wake up receiver (WUR) and an OFDM (orthogonal frequency division multiplexing) based WUR.

14. In paragraph 13, Manchester coding is applied to the above WUS. One or M OOK pulses of the WUS are included within the OFDM symbol interval, A base station, characterized in that the above M includes 2 and 4.

15. In paragraph 13, The above WUS is based on a specific OFDM sequence within the pulse time unit corresponding to the on pulse, A base station, wherein the specific OFDM sequence is set by the base station or is one of a set of OFDM sequences.

Images