WO2025234861A1 - Method and device for transmitting or receiving low-power synchronization signal group on basis of overlaid sequence in wireless communication system - Google Patents

Abstract

A method and a device for transmitting or receiving a low power-synchronization signal (LP-SS) on the basis of an overlaid sequence in a wireless communication system are disclosed. The method according to one embodiment of the present disclosure may comprise steps in which a terminal: acquires information related to a sequence overlaid on a synchronization signal; and receives the synchronization signal from a network on the basis of the information related to the overlaid sequence. The overlaid sequence can correspond to one of sequence candidates.

Description

Method and device for transmitting or receiving a group of overlaid sequence-based low-power synchronization signals in a wireless communication system

The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for transmitting or receiving a low power-synchronization signal (LP-SS) based on an overlaid sequence in a wireless communication system.

The fifth generation (5G) wireless communication system, the successor to 4G LTE (long-term evolution), is a new, clean-slate mobile communication system characterized by high performance, low latency, and high availability. 5G NR (New Radio) can utilize all available spectrum resources, from low-frequency bands below 1 GHz, to intermediate-frequency bands between 1 GHz and 10 GHz, and to high-frequency (or millimeter wave) bands above 24 GHz. 6G wireless communication systems are being developed based on the underlying technologies of 5G wireless communication.

The 6G wireless communication system is being developed with the goals of (i) very high data rates per device, (ii) a very large number of connected devices, (iii) global connectivity, (iv) very low latency, (v) reduced energy consumption of battery-free Internet of Things (IoT) devices, (vi) ultra-reliable connectivity, and (vii) connected intelligence with machine learning capabilities. The vision of the 6G system can be divided into four aspects: intelligent connectivity, deep connectivity, holographic connectivity, and ubiquitous connectivity. Considering the requirements of the 6G system, such as a peak data rate of 1 Tbps per device, an end-to-end latency of 1 ms, a maximum spectrum efficiency of 100 bps/Hz, support for mobility of 1000 km/h, satellite integration, artificial intelligence (AI), autonomous vehicles, extended reality (XR), and haptic communication, various technologies are being researched.

The technical problem of the present disclosure is to provide a method and device for transmitting or receiving a low power-synchronization signal (LP-SS) based on an overlaid sequence in a wireless communication system.

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

A method according to one aspect of the present disclosure may include the steps of: obtaining, by a terminal, information related to a sequence overlaid on a synchronization signal; and receiving, by the terminal, the synchronization signal from a network based on the information related to the overlaid sequence. The overlaid sequence may correspond to one of the sequence candidates.

A method according to an additional aspect of the present disclosure may include the steps of: providing, by a base station, information related to a sequence overlaid on a synchronization signal to a terminal; and transmitting, by the base station, the synchronization signal to the terminal based on the information related to the overlaid sequence. The overlaid sequence may correspond to one of the sequence candidates.

According to the present disclosure, a method and device for transmitting or receiving a low power-synchronization signal (LP-SS) based on an overlaid sequence in a wireless communication system can be provided.

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

The accompanying drawings, which are incorporated in and are part of the detailed description to aid in understanding the present disclosure, provide embodiments of the present disclosure and, together with the detailed description, describe the technical features of the present disclosure.

Figure 1 illustrates a flexible network topology to which some examples of the present disclosure may be applied.

FIG. 2 illustrates an example of a communication system to which some examples of the present disclosure may be applied.

FIG. 3 illustrates an example of a wireless device to which some examples of the present disclosure may be applied.

FIG. 4 exemplarily illustrates a communication procedure between a first node and a second node to which some examples of the present disclosure may be applied.

FIG. 5 illustrates a functional framework for AI operations to which some examples of the present disclosure may be applied.

FIG. 6 illustrates an example of operations related to AI model training and AI model inference to which some examples of the present disclosure may be applied.

FIG. 7 illustrates another example of operations related to AI model training and AI model inference to which some examples of the present disclosure may be applied.

FIG. 8 illustrates another example of operations related to AI model training and AI model inference to which some examples of the present disclosure may be applied.

FIG. 9 illustrates an electromagnetic spectrum to which some examples of the present disclosure may be applied.

FIG. 10 illustrates an example of a system information transmission/reception procedure to which some examples of the present disclosure may be applied.

FIG. 11 exemplarily illustrates a beam management procedure to which some examples of the present disclosure may be applied.

Figures 12 and 13 illustrate examples of NTN scenarios to which some examples of the present disclosure may be applied.

FIG. 14 illustrates examples of sensing operations to which some examples of the present disclosure may be applied.

FIG. 15 and FIG. 16 are diagrams for explaining examples of the OOK method for an LP signal according to the present disclosure.

FIG. 17 is a diagram illustrating an example of an SSB time resource to which the present disclosure can be applied.

FIG. 18 is a drawing for explaining an example of a method performed by a terminal according to the present disclosure.

FIG. 19 is a drawing illustrating an example of a method performed by a base station according to the present disclosure.

FIG. 20 is a diagram showing an example of a case where a cyclic shift value K is applied to a sequence of length L according to the present disclosure.

FIGS. 21 to 23 are drawings for explaining examples of terminal and base station operations according to the present disclosure.

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to explain exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure may be practiced. The following detailed description includes specific details to provide a thorough understanding of the present disclosure. However, one of ordinary skill in the art will appreciate that the present disclosure may be practiced without these specific details.

In some cases, to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or illustrated in block diagram form focusing on the core functions of each structure and device.

In the present disclosure, when a component is said to be "connected," "coupled," or "connected" to another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, the terms "comprises" or "has" in the present disclosure specify the presence of the mentioned features, steps, operations, elements, and/or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.

In this disclosure, terms such as “first,” “second,” etc. are used only to distinguish one component from another and are not used to limit the components, and do not limit the order or importance between the components unless specifically stated otherwise. Accordingly, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise.

In this disclosure, "A or B" can mean "only A," "only B," or "both A and B." In other words, "A or B" in this disclosure can be interpreted as "A and/or B." For example, "A, B or C" in this disclosure can mean "only A," "only B," "only C," or "any combination of A, B and C."

As used herein, a slash (/) or a comma may mean "and/or." For example, "A/B" may mean "A and/or B." Accordingly, "A/B" may mean "only A," "only B," or "both A and B." For example, "A, B, C" may mean "A, B, or C."

In the present disclosure, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Additionally, in the present disclosure, the expressions “at least one of A or B” or “at least one of A and/or B” may be interpreted identically to “at least one of A and B.”

Additionally, in the present disclosure, “at least one of A, B and C” can mean “only A,” “only B,” “only C,” or “any combination of A, B and C.” Additionally, “at least one of A, B or C” or “at least one of A, B and/or C” can mean “at least one of A, B and C.”

Additionally, parentheses used in the present disclosure may mean "for example." Specifically, when indicated as "control information (PDCCH)", "PDCCH" may be described as an example of "control information." In other words, "control information" in the present disclosure is not limited to "PDCCH," and "PDCCH" may be described as an example of "control information." Furthermore, even when indicated as "control information (i.e., PDCCH)", "PDCCH" may be described as an example of "control information."

In the following description, 'when, if, in case of' can be replaced with 'based on'.

Technical features individually described in one drawing in this disclosure may be implemented individually or simultaneously.

In the present disclosure, a terminal or user equipment (UE) may be a portable device and may be a first node that receives a signal from a base station/second node/IAB (integrated access backhaul) node.

In the present disclosure, a base station (BS) may be a second node/IAB node/Transmission-Reception Point (TRP).

In the present disclosure, higher layer parameters may be parameters configured, pre-configured, or pre-defined for the terminal. For example, a base station or a network may transmit higher layer parameters to the terminal. For example, the higher layer parameters may be transmitted via radio resource control (RRC) signaling or medium access control (MAC) signaling.

In the present disclosure, "setting or defining" may be interpreted as being set to a device through predefined signaling (e.g., SIB (system information block), MAC, RRC) from a base station or network. In the present disclosure, "setting or defining" may be interpreted as being set to a device through separate signaling or being defined in advance without separate signaling.

In the present disclosure, transmitting or receiving a channel means transmitting or receiving information or a signal through the channel. For example, transmitting a control channel means transmitting control information or a signal through the control channel. Similarly, transmitting a data channel means transmitting data information or a signal through the data channel.

The technology described in the present disclosure can be used in various wireless communication systems such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access). CDMA can be implemented with wireless technologies such as UTRA (universal terrestrial radio access) or CDMA2000. TDMA can be implemented with wireless technologies such as GSM (global system for mobile communications)/GPRS (general packet radio service)/EDGE (enhanced data rates for GSM evolution). OFDMA can be implemented with wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, E-UTRA (evolved UTRA), LTE (long term evolution), and 5G NR.

The technology described in the present disclosure can be implemented with 6G wireless technology and applied to various 6G systems. For example, the 6G system can have key factors such as enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), massive machine-type communication (mMTC), artificial intelligence (AI) integrated communication, tactile internet, high throughput, high network capacity, high energy efficiency, low backhaul and access network congestion, and enhanced data security.

Network structure

Figure 1 illustrates a flexible network topology to which some examples of the present disclosure may be applied.

To compensate for incomplete network coverage areas, a network topology that allows for more flexible and resilient split radio access networks (RANs) may be considered. For this purpose, various nodes, such as integrated access backhaul (IAB) nodes, relays, and radio frequency (RF) repeaters, as illustrated in Figure 1, may be applied, or a non-terrestrial network (NTN) may be integrated. For example, an IAB node may correspond to a node that provides wireless backhaul. For example, a relay may refer to any intermediate point, and in the case of a sidelink relay where a terminal functions as a relay, it may collectively refer to a terminal-to-network (U2N) relay and a terminal-to-terminal (U2U) relay. For example, an RF repeater may correspond to a node that simply performs the function of signal amplification and forwarding, or in the case of a network-controlled repeater, it may not only amplify and forward signals but also adjust its transmission and reception settings based on information provided by the network. For example, NTN nodes could be satellites or aircraft that provide NTN coverage that terrestrial networks struggle to provide. Beyond these examples, various intermediate points can be introduced to improve the network topology.

Referring to Figure 1, a split RAN can support the division of a base station into a centralized unit (CU) and one or more distributed units (DUs). The CU and DU can correspond to logical units. The CU can be further divided into a control plane (CP) portion and one or more user plane (UP) portions. Since a failure in the CU-CP affects not only the CU-UP but also the DUs, various intermediate points can be introduced to compensate for this.

An intermediate point may correspond to a terminal or a base station, depending on its relationship to other nodes. For example, an IAB node may include a mobile-termination (MT) portion and a unit (DU). The MT may connect the IAB node to a donor node. The unit (DU) of an IAB node may serve other terminals or connect to other IAB nodes to provide multi-hop wireless backhaul to the terminal. For example, an IAB node may correspond to a base station in its relationship to a user-side node, and to a terminal in its relationship to a network-side node.

In some examples of the present disclosure, the description of a terminal may equally apply not only to a user-side endpoint, but also to an intermediate point corresponding to a terminal in a relative relationship with a network-side endpoint. Similarly, in some examples of the present disclosure, the description of a base station may equally apply not only to a network-side endpoint, but also to an intermediate point corresponding to a base station in a relative relationship with a user-side endpoint. In most cases where there is no additional description of the operations of three or more entities, the communicating entities in the present disclosure are briefly described as terminals and/or base stations (or first nodes and/or second nodes), where the terms terminal and/or base stations (or first nodes and/or second nodes) are interpreted to include/replace any endpoint or any intermediate point in relation to other nodes.

As such, in some examples of the present disclosure, for the sake of simplicity of explanation, the subjects of the operation may be referred to as terminals and/or base stations (or first nodes and/or second nodes). In addition, the terms terminal and/or base station (or first node and/or second node) may also be interpreted/replaced as in the following examples: For example, the terminal (or first node) and the base station (or second node) may respectively correspond to the first endpoint and the second endpoint; may respectively correspond to the endpoint and the intermediate point; may respectively correspond to the intermediate point and the endpoint; or may respectively correspond to the first intermediate point and the second intermediate point.

In the present disclosure, there may be zero or more intermediate points between the base station and the terminal. If an intermediate point exists, it may correspond to an IAB node/relay/RF repeater/NTN node, or a node supporting other functions. The intermediate point may be a node with a fixed location or a node with an unfixed location.

Systems applicable to this disclosure

FIG. 2 illustrates an example of a communication system to which some examples of the present disclosure may be applied.

The communication system (100) applied to the present disclosure includes a wireless device (110), a network device (120), and a network (130). Here, the wireless device (110) refers to a device that performs communication using a wireless access technology (e.g., LTE, LTE-A, LTE-A pro, NR, 5G, 5G-A, 6G) and may be referred to as a communication/wireless/5G/6G device. Although not limited thereto, the wireless device (110) may include a robot (110a), a vehicle (110b-1, 110b-2), an XR (extended reality) device (110c), a hand-held device (110d), a home appliance (110e), an IoT (Internet of Things) device (110f), and an AI (artificial intelligence) device/server (110g). For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing vehicle-to-vehicle communication, etc. Here, the vehicle (110b-1, 110b-2) may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device (110c) includes an augmented reality (AR)/virtual reality (VR)/mixed reality (MR) device, and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) equipped in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, digital signage, a vehicle, a robot, etc. The portable device (110d) may include a smartphone, a smart pad, a wearable device (e.g., a smart watch, smart glasses), a computer (e.g., a laptop, etc.), etc. The home appliance (110e) may include a TV, a refrigerator, a washing machine, etc. The IoT device (110f) may include a sensor, a smart meter, etc. The wireless device (110) may correspond to a terminal (or first node) or an intermediate point. The network device (120) may correspond to a base station (or second node) or another intermediate point. For example, the network device (120) may also be implemented as a wireless device (110), and a specific wireless device (120a) may act as a network device (120) to another wireless device (110).

Wireless devices (110a to 110f) can be connected to a network (130) via a network device (120). AI technology can be applied to the wireless devices (110a to 110f), and the wireless devices (110a to 110f) can be connected to an AI server (110g) via a network (130). The network (130) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR), or a 6G network. The wireless devices (110a to 110f) can communicate with each other via the network device (120)/network (130), but can also communicate directly (e.g., sidelink communication) without going through the network device (120)/network (130). For example, vehicles (110b-1, 110b-2) can communicate directly (e.g., V2V (vehicle to vehicle)/V2X (vehicle to everything) communication). Additionally, an IoT device (110f) (e.g., a sensor) can communicate directly with another IoT device (e.g., a sensor) or another wireless device (110a to 110f).

Wireless communication/connection (150a, 150b, 150c) can be established between wireless devices (110a to 110f)/network devices (120), network devices (120)/network devices (120). Here, the wireless communication/connection can be established through various wireless access technologies such as uplink/downlink communication (150a), sidelink communication (150b) (or D2D communication), and communication between network devices (150c) (e.g., relay, IAB (integrated access backhaul)). Through the wireless communication/connection (150a, 150b, 150c), the wireless device and the network device/wireless device, and the network device and the network device can transmit/receive wireless signals to each other. For example, the wireless communication/connection (150a, 150b, 150c) can transmit/receive signals through various physical channels. To this end, based on various descriptions of the present disclosure, at least some of various configuration information setting processes for transmitting/receiving wireless signals, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, resource mapping/demapping, etc.), resource allocation processes, etc., may be performed.

Device applicable to the present disclosure

FIG. 3 illustrates an example of a wireless device to which some examples of the present disclosure may be applied.

Referring to FIG. 3, the wireless device (200) can transmit and receive wireless signals via various wireless access technologies (e.g., LTE, LTE-A, LTE-A pro, NR, 5G, 5G-A, 6G). The wireless device (200) includes at least one processor (202) and at least one memory (204), and may additionally include at least one transceiver (206) and/or at least one antenna (208).

The processor (202) controls the memory (204) and/or the transceiver (206), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document. For example, the processor (202) may process information in the memory (204) to generate first information/signal, and then transmit a wireless signal including the first information/signal via the transceiver (206). In addition, the processor (202) may receive a wireless signal including second information/signal via the transceiver (206), and then store information obtained from signal processing of the second information/signal in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may store software code including instructions for performing some or all of the processes controlled by the processor (202), or for performing the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein. Here, the processor (202) and the memory (204) may be part of a communication modem/circuit/chip designed to implement wireless communication technology. The transceiver (206) may be connected to the processor (202) and may transmit and/or receive wireless signals via at least one antenna (208). The transceiver (206) may include a transmitter and/or a receiver. The transceiver (206) may be used interchangeably with an RF (radio frequency) unit. In the present disclosure, a wireless device may also mean a communication modem/circuit/chip.

Hereinafter, the hardware elements of the wireless device (200) will be described in more detail. Although not limited thereto, at least one protocol layer may be implemented by at least one processor (202). For example, at least one processor (202) may implement at least one layer (e.g., a functional layer such as physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), radio resource control (RRC), and service data adaptation protocol (SDAP)). At least one processor (202) may generate at least one Protocol Data Unit (PDU) and/or at least one Service Data Unit (SDU) according to the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document. At least one processor (202) may generate a message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document. At least one processor (202) can generate a signal (e.g., a baseband signal) comprising a PDU, an SDU, a message, control information, data or information according to the functions, procedures, proposals and/or methods disclosed in this document, and provide the signal to at least one transceiver (206). At least one processor (202) can receive a signal (e.g., a baseband signal) from at least one transceiver (206) and obtain the PDU, SDU, message, control information, data or information according to the descriptions, functions, procedures, proposals, methods and/or operational flowcharts disclosed in this document.

At least one processor (202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. The at least one processor (202) may be implemented by hardware, firmware, software, or a combination thereof. For example, at least one application specific integrated circuit (ASIC), at least one digital signal processor (DSP), at least one digital signal processing device (DSPD), at least one programmable logic device (PLD), or at least one field programmable gate array (FPGA) may be included in the at least one processor (202). The descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document may be included in the at least one processor (202), or may be stored in at least one memory (204) and driven by the at least one processor (202). The descriptions, functions, procedures, suggestions, methods and/or flowcharts disclosed in this document may be implemented using firmware or software in the form of code, instructions and/or sets of instructions.

At least one memory (204) can be connected to at least one processor (202) and can store various forms of data, signals, messages, information, programs, codes, instructions and/or commands. The at least one memory (204) can be configured as a read only memory (ROM), a random access memory (RAM), an erasable programmable read only memory (EPROM), a flash memory, a hard drive, a register, a cache memory, a computer readable storage medium and/or a combination thereof. The at least one memory (204) can be located internally and/or externally to the at least one processor (202). In addition, the at least one memory (204) can be connected to the at least one processor (202) via various technologies such as a wired or wireless connection.

At least one transceiver (206) can transmit user data, control information, wireless signals/channels, etc., mentioned in the methods and/or flowcharts of this document to at least one other device. At least one transceiver (206) can receive user data, control information, wireless signals/channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods and/or flowcharts disclosed in this document from at least one other device. For example, at least one transceiver (206) can be connected to at least one processor (202) and can transmit and receive wireless signals. For example, at least one processor (202) can control at least one transceiver (206) to transmit user data, control information, or wireless signals to at least one other device. Furthermore, at least one processor (202) can control at least one transceiver (206) to receive user data, control information, or wireless signals from at least one other device. In addition, at least one transceiver (206) may be connected to at least one antenna (208), and at least one transceiver (206) may be configured to transmit and receive user data, control information, wireless signals/channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods and/or operation flowcharts disclosed in this document via at least one antenna (208). In this document, at least one antenna may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). At least one transceiver (206) may convert the received wireless signals/channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals/channels, etc. using at least one processor (202). At least one transceiver (206) may convert the processed user data, control information, wireless signals/channels, etc. from baseband signals to RF band signals using at least one processor (202). For this purpose, at least one transceiver (206) may include an (analog) oscillator and/or filter.

The components of the wireless device described with reference to FIG. 3 may be referred to by different terms in terms of functionality. For example, the processor (202) may be referred to as a control unit, the transceiver (206) as a communication unit, and the memory (204) as a storage unit. In some cases, the communication unit may be used to mean at least a portion of the processor (202) and the transceiver (206).

The structure of the wireless device described with reference to FIG. 3 can be understood as the structure of at least a portion of various devices. For example, the structure of the wireless device illustrated in FIG. 3 can be at least a portion of various devices described with reference to FIG. 2 (e.g., a robot (110a), a vehicle (110b-1, 110b-2), an XR device (110c), a portable device (110d), a home appliance (110e), an IoT device (110f), an AI device/server (110g)). Furthermore, according to various embodiments, in addition to the components illustrated in FIG. 3, the device may further include other components.

For example, the device may be a portable device such as a smartphone, a smart pad, a wearable device (e.g., a smart watch, smart glasses), or a portable computer (e.g., a laptop, etc.). In this case, the device may further include at least one of a power supply unit that supplies power and includes a wired/wireless charging circuit, a battery, etc., an interface unit that includes at least one port for connection with another device (e.g., an audio input/output port, a video input/output port), and an input/output unit for inputting and outputting image information/signals, audio information/signals, data, and/or information input from a user.

For example, the device may be a mobile device such as a mobile robot, a vehicle, a train, an aerial vehicle (AV), a ship, etc. In this case, the device may further include at least one of a driving unit including at least one of an engine, a motor, a power train, wheels, brakes, and a steering unit of the device, a power supply unit including a wired/wireless charging circuit, a battery, etc. that supplies power, a sensor unit that senses status information, environmental information, and user information of the device or its surroundings, an autonomous driving unit that performs functions such as path maintenance, speed control, and destination setting, and a position measurement unit that obtains location information of the mobile device through a global positioning system (GPS) and various sensors.

For example, the device may be an XR device such as an HMD, a head-up display (HUD) installed in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, etc. In this case, the device may further include at least one of a power supply unit that supplies power and includes a wired/wireless charging circuit, a battery, etc., an input/output unit that obtains control information, data, etc. from the outside and outputs the generated XR object, and a sensor unit that senses status information, environmental information, and user information of the device or the surroundings of the device.

For example, the device may be a robot that can be classified into industrial, medical, household, military, etc. types depending on the purpose or field of use. In this case, the device may further include at least one of a sensor unit that senses status information, environmental information, and user information of the device or its surroundings, and a driving unit that performs various physical actions, such as moving the robot joints.

For example, the device may be an AI device such as a TV, a projector, a smartphone, a PC, a laptop, a digital broadcasting terminal, a tablet PC, a wearable device, a set-top box (STB), a radio, a washing machine, a refrigerator, digital signage, a robot, a vehicle, etc. In this case, the device may further include at least one of an input unit that acquires various types of data from the outside, an output unit that generates output related to sight, hearing, or touch, a sensor unit that senses status information, environmental information, and user information of the device or its surroundings, and a training unit that trains a model composed of an artificial neural network using learning data.

The structure of the wireless device illustrated in FIG. 3 may be understood as a part of a terminal (or first node), or as a part of an intermediate point, or as a part of a base station (or second node). If the device illustrated in FIG. 3 is a base station (or second node), the device may further include a wired transceiver for front haul and/or back haul communications. If the front haul and/or back haul communications are based on wireless communications, at least one transceiver (206) illustrated in FIG. 3 may be used for front haul and/or backhaul communications, and a wired transceiver may not be included.

Communication procedures

FIG. 4 exemplarily illustrates a communication procedure between a first node and a second node to which some examples of the present disclosure may be applied.

FIG. 4 illustrates operations of a first node (110) (e.g., a terminal) and a second node (120) (e.g., a base station) transmitting and/or receiving data and operations performed prior thereto.

In step S101, the first node (110) and the second node (120) can perform synchronization. For example, the terminal (110) performs an initial cell search operation. Specifically, the terminal (110) can detect at least one synchronization signal transmitted from the base station (120) according to a predefined rule. Here, the synchronization signal can include a plurality of synchronization signals (e.g., a primary synchronization signal, a secondary synchronization signal) classified according to a structure or purpose. Through this, the terminal (110) can confirm the boundaries of the frame, subframe, slot, and/or symbol of the base station (120) and obtain information (e.g., a cell identifier) about the base station (120).

In step S103, the first node (110) can obtain system information transmitted from the second node (120). For example, the system information is information related to the properties, characteristics, and/or capabilities of the base station (120) required to access the base station (120) and use the service, and can be classified according to the content (e.g., whether it is essential for access), transmission structure (e.g., the channel used, whether it is provided in an on-demand manner), etc., and can be classified into, for example, a master information block (MIB) and a system information block (SIB). If necessary, the terminal (110) can transmit a signal requesting system information before receiving the system information. Such requesting and providing of system information may be performed after a random access procedure described below.

In step S105, the first node (110) and the second node (120) can perform a random access procedure. For example, the terminal (110) can transmit and/or receive at least one message (e.g., a random access preamble, a random access response (RAR) message, etc.) for a random access procedure based on information related to a random access channel of the base station (120) obtained through system information (e.g., channel position, channel structure, structure of a supported preamble, etc.). For example, the terminal (110) may transmit a preamble (e.g., message 1 (MSG1)) over a random access channel, receive a random access response (RAR) message (e.g., message 2 (MSG2)), transmit a message (e.g., message 3 (MSG3)) including information related to the terminal (110) (e.g., identification information) using scheduling information included in the RAR message to the base station (120), and receive a message for contention resolution and/or connection establishment (e.g., message 4 (MSG4)). As another example, MSG1 and MSG3 may be transmitted and received as one message (e.g., message A (MSG A)), or MSG2 and MSG4 may be transmitted and received as one message (e.g., message B (MSG B)).

In step S107, the first node (110) and the second node (120) can perform signaling of control information. For example, the control information can be defined in various layers, such as a layer that controls a connection (e.g., a radio resource control (RRC) layer), a layer that handles mapping between logical channels and transmission channels (e.g., a media access control (MAC) layer), and a layer that handles physical channels (e.g., a physical (PHY) layer). For example, the terminal (110) and the base station (120) can perform at least one of signaling for establishing a connection, signaling for determining settings related to communication, and signaling for indicating allocated resources.

In step S109, the first node (110) and the second node (120) can transmit and/or receive data. For example, the terminal (110) and the base station (120) can process, transmit, and/or receive data based on signaling of control information. For example, when transmitting data, the terminal (110) or the base station (120) can perform at least one of channel encoding, rate matching, scrambling, constellation mapping, layer mapping, waveform modulation, antenna mapping, and resource mapping on information bits. For example, when receiving data, the terminal (110) or the base station (120) can perform at least one of signal extraction from resources, waveform demodulation for each antenna, signal arrangement considering layer mapping, constellation demapping, descrambling, and channel decoding.

6G system core technologies

As core implementation technologies of the 6G system, technologies such as artificial intelligence (AI), THz (terahertz) communication, optical wireless technology, free space optics (FSO) backhaul network, massive MIMO (multiple input multiple output) technology, blockchain, 3D networking, quantum communication, unmanned aerial vehicles, cell-free communication, wireless information and energy transfer (WIET), integration of sensing and communication, integration of access backhaul networks, holographic beamforming, big data analysis, and large intelligent surface (LIS) can be adopted.

artificial intelligence

Incorporating AI into communications can streamline and improve real-time data transmission. AI can use numerous analytics to determine how complex target tasks should be performed. AI can increase efficiency and reduce processing delays. Time-consuming tasks such as handovers, network selection, and resource scheduling can be performed instantly using AI. AI can also play a crucial role in machine-to-machine (M2M), machine-to-human, and human-to-machine communications. Furthermore, AI can facilitate rapid communication in brain-computer interfaces (BCIs). AI-based communication systems can be supported by metamaterials, intelligent structures, intelligent networks, intelligent devices, intelligent cognitive radios, self-sustaining wireless networks, and machine learning.

FIG. 5 illustrates a functional framework for AI operations to which some examples of the present disclosure may be applied.

Below, to explain AI (or AI/ML (machine learning)) in more detail, the terms can be defined as follows.

- Data collection: Data collected from network nodes, management entities, or terminals as a basis for AI model training, data analysis, and inference.

- AI model: A data-driven algorithm that applies AI technology to generate a set of outputs containing predictive information and/or decision parameters based on a set of inputs.

- AI/ML training: An online or offline process of training an AI model by learning features and patterns that best represent the data and obtain a trained AI/ML model for inference.

- AI/ML inference: The process of making predictions or inducing decisions based on collected data and the AI model using a trained AI model.

Referring to FIG. 5, the data collection function (10) is a function that collects input data and provides processed input data to the model training function (20) and the model inference function (30).

Examples of input data may include measurements from terminals or other network entities, feedback from actors, and output from AI models.

The data collection function (10) performs data preparation based on input data and provides input data processed through the data preparation. Here, the data collection function (10) does not perform data preparation specific to each AI algorithm (e.g., data pre-processing and cleaning, formatting, and transformation), but can perform data preparation common to all AI algorithms.

After the data preparation process is performed, the data collection function (10) may provide training data (11) to the model training function (20) and may provide inference data (12) to the model inference function (30). Here, the training data (11) may correspond to data required as input for the AI model training function (20), and the inference data (12) may correspond to data required as input for the AI model inference function (30).

The data collection function (10) may be performed by a single entity (e.g., a terminal, a RAN node, a network node, etc.), but may also be performed by multiple entities. In this case, training data (11) and inference data (12) may be provided to the model training function (20) and model inference function (30), respectively, from multiple entities.

The model training function (20) may correspond to a function that performs AI model training, validation, and testing, which can generate model performance metrics as part of the AI model testing procedure. If necessary, the model training function (20) may also be responsible for data preparation (e.g., data pre-processing and cleaning, formatting, and transformation, etc.) based on training data (11) provided by the data collection function (10).

Here, model deployment/update (13) can be used to initially deploy a trained, validated and tested AI model to the model inference function (30) or to provide an updated model to the model inference function (30).

The model inference function (30) may correspond to a function that provides AI model inference output (16) (e.g., prediction or decision). If applicable, the model inference function (30) may provide model performance feedback (14) to the model training function (20). In addition, the model inference function (30) may also be responsible for data preparation (e.g., data pre-processing and cleaning, formatting and transformation, etc.) based on inference data (12) provided by the data collection function (10), if necessary.

Here, output (16) refers to the inference output of the AI model generated by the model inference function (30), and the details of the inference output may vary depending on the use case.

Model performance feedback (14) can be used to monitor the performance of the AI model, if available, and this feedback may be omitted.

An actor function (40) is a function that receives an output (16) from a model inference function (30) and triggers or performs a corresponding task/action. The actor function (40) can trigger tasks/actions for other entities (e.g., one or more terminals, one or more RAN nodes, one or more network nodes, etc.) or for itself.

Feedback (15) can be used to derive training data (11), inference data (12), or to monitor the performance of the AI model, its impact on the network, etc.

Meanwhile, the definitions of training/validation/test in data sets used in AI/ML can be distinguished as follows.

- Training data: refers to a data set for learning a model.

- Validation data: This refers to a dataset used to validate a model that has already completed training. Validation data can typically be used to prevent overfitting of the training data set. It can also be used to select the best model among the various models learned during the training process. Therefore, validation can be considered a type of learning.

- Test data: This refers to the data set for final evaluation. This data is unrelated to learning.

For example, the training and validation data can be divided into an 8:2 or 7:3 ratio within the entire data set. Alternatively, the training data:validation data:test data can be divided into a 6:2:2 ratio within the entire data set.

The level of cooperation can be defined as follows depending on whether the base station and the terminal have capabilities for AI/ML functions, and variations due to combination of multiple levels or separation of any one level are also possible.

Category 0a: This category corresponds to a no-collaboration framework. In this case, AI/ML algorithms are purely implementation-based and may not require any changes to the wireless interface.

Category 0b: Frameworks that involve a wireless interface modified to fit efficient implementation-based AI/ML algorithms, but without collaboration.

Category 1: This category applies to cases where inter-node support is required to improve the AI/ML algorithms of each node. For example, this applies when a terminal receives support from a base station (for training, adaptation, etc.), and vice versa. At this level, model exchange between network nodes is not required.

Category 2: This applies to cases where joint ML tasks can be performed between terminals and base stations. This level requires exchange of AI/ML model commands or network nodes.

The functions exemplified in FIG. 5 above may be implemented in a RAN node (e.g., a base station, a TRP, a CU of a base station, etc.), a network node, an OAM (operation administration maintenance) of a network operator, or a terminal.

Alternatively, two or more entities, such as a RAN, a network node, a network operator's OAM, or a terminal, may cooperate to implement the functions illustrated in FIG. 5. For example, one entity may perform some of the functions of FIG. 5, and another entity may perform the remaining functions. In this way, since some of the functions illustrated in FIG. 5 are performed by a single entity (e.g., a terminal, a RAN node, a network node, etc.), the transmission/provision of data/information between each function may be omitted. For example, if the model training function (20) and the model inference function (30) are performed by the same entity, the transmission/provision of model deployment/update (13) and model performance feedback (14) may be omitted.

Alternatively, any one of the functions illustrated in FIG. 5 may be performed collaboratively by two or more entities, including a RAN, a network node, a network operator's OAM, or a terminal. This may be referred to as a split AI operation.

FIG. 6 illustrates an example of operations related to AI model training and AI model inference to which some examples of the present disclosure may be applied.

For example, the AI model training function may be performed by a network node (e.g., a core network node, an OAM of a network operator, etc.), and the AI model inference function may be performed by a RAN node (e.g., a base station, a TRP, a CU of a base station, etc.).

Step 1: RAN node 1 and RAN node 2 can transmit input data (e.g., training data) for AI model training to the network node. Here, RAN node 1 and RAN node 2 can also transmit data collected from the terminal (e.g., terminal measurements related to RSRP (reference signal received power), RSRQ (reference signal received quality), SINR (signal to interference-plus-noise ratio) of the serving cell and neighboring cells, terminal location, speed, etc.) to the network node.

Step 2: Network nodes can train AI models using the received training data.

Step 3: The network node may distribute/update the AI model to RAN node 1 and/or RAN node 2. RAN node 1 (and/or RAN node 2) may also continue model training based on the received AI model.

For convenience of explanation, we assume that the AI model is deployed/updated only to RAN node 1.

Step 4: RAN node 1 can receive input data (e.g., inference data) for AI model inference from the terminal and RAN node 2.

Step 5: RAN node 1 can perform AI model inference using the received inference data to generate output data (e.g., prediction or decision).

Step 6: If applicable, RAN node 1 may send model performance feedback to the network nodes.

Step 7: RAN node 1, RAN node 2, and the terminal (or 'RAN node 1 and the terminal', or 'RAN node 1 and RAN node 2') may perform actions based on the output data. For example, in the case of a load balancing operation, the terminal may move from RAN node 1 to RAN node 2.

Step 8: RAN node 1 and RAN node 2 can transmit feedback information to the network nodes.

FIG. 7 illustrates another example of operations related to AI model training and AI model inference to which some examples of the present disclosure may be applied.

For example, both AI model training functions and AI model inference functions can be performed by RAN nodes (e.g., base stations, TRPs, CUs of base stations, etc.).

Step 1: The terminal and RAN node 2 can transmit input data (e.g., training data) for AI model training to RAN node 1.

Step 2: RAN node 1 can train an AI model using the received training data.

Step 3: RAN node 1 can receive input data (e.g., inference data) for AI model inference from the terminal and RAN node 2.

Step 4: RAN node 1 can perform AI model inference using the received inference data to generate output data (e.g., prediction or decision).

Step 5: RAN node 1, RAN node 2, and the terminal (or 'RAN node 1 and the terminal', or 'RAN node 1 and RAN node 2') may perform actions based on the output data. For example, in the case of a load balancing operation, the terminal may move from RAN node 1 to RAN node 2.

Step 6: RAN node 2 may transmit feedback information to RAN node 1.

FIG. 8 illustrates another example of operations related to AI model training and AI model inference to which some examples of the present disclosure may be applied.

For example, the AI model training function may be performed by a RAN node (e.g., a base station, a TRP, a CU of a base station, etc.), and the AI model inference function may be performed by a terminal.

Step 1: The terminal may transmit input data (e.g., training data) for AI model training to the RAN node. Here, the RAN node may collect data (e.g., terminal measurements related to RSRP, RSRQ, SINR of the serving cell and neighboring cells, terminal location, speed, etc.) from various terminals and/or from other RAN nodes.

Step 2: RAN nodes can train AI models using the received training data.

Step 3: The RAN node can distribute/update the AI model to the terminal. The terminal can also continue model training based on the received AI model.

Step 4: Input data (e.g., inference data) for AI model inference can be received from the terminal and RAN node (and/or from another terminal).

Step 5: The terminal can perform AI model inference using the received inference data to generate output data (e.g., prediction or decision).

Step 6: If applicable, the terminal may send model performance feedback to the RAN node.

Step 7: The terminal and RAN node can perform actions based on the output data.

Step 8: The terminal may transmit feedback information to the RAN node.

THz communication (terahertz communication)

Data transmission rates can be increased by increasing bandwidth. This can be achieved by utilizing sub-THz communications with wide bandwidths and applying advanced massive MIMO technology. THz waves, also known as sub-millimeter waves, typically refer to the frequency range between 0.1 THz and 10 THz, with corresponding wavelengths ranging from 0.03 mm to 3 mm. The 100 GHz to 300 GHz band (the sub-THz band) is considered a key part of the THz spectrum for cellular communications. Adding the sub-THz band to the mmWave band will increase 6G cellular capacity. Among the defined THz bands, 300 GHz to 3 THz lies in the far infrared (IR) frequency band. While part of the optical band, the 300 GHz to 3 THz band lies at the boundary of the optical band, immediately following the RF band. Therefore, this 300 GHz to 3 THz band exhibits similarities to RF.

FIG. 9 illustrates an electromagnetic spectrum to which some examples of the present disclosure may be applied.

Key characteristics of THz communications include (i) the widely available bandwidth to support very high data rates, and (ii) the high path loss at high frequencies (which necessitates highly directional antennas). The narrow beamwidths generated by highly directional antennas reduce interference. The small wavelength of THz signals allows for a significantly larger number of antenna elements to be integrated into devices and base stations operating in this band. This enables the use of advanced adaptive array technologies to overcome range limitations.

Transmitting system information (e.g., MIB) in a cell in the THz frequency band can be inefficient because the beam width in high-frequency bands narrows, requiring more beam sweeps to cover the entire cell area. This method is particularly inefficient when there are only a few users within the cell.

FIG. 10 illustrates an example of a system information transmission/reception procedure to which some examples of the present disclosure may be applied.

The example of Fig. 10 is applicable not only to THz communication environments but also to 6G communication environments where THz communication is not applicable. Furthermore, the procedure illustrated in Fig. 10 can be combined with various embodiments of the present disclosure described below. For example, the embodiments described below can be performed based on system information acquired through the procedure illustrated in Fig. 10.

In step S1010, the second node (120) (e.g., base station) can transmit system information of cell #1 via cell #2. For example, the base station provides at least two cells, cell #1 uses a THz frequency band, and cell #2 uses a frequency band other than the THz frequency band. Here, the system information may include at least one of an SFN (system frame number), a PDCCH configuration for SIB1, cell barring, cell re-selection, and subcarrier spacing generated in a higher layer, and may include at least one of an SFN, a half frame indicator, and an SSB index (synchronization signal/PBCH (physical broadcast channel) block index) generated in a physical layer. For this purpose, as an example, cell #1 and cell #2 may have a relationship of a secondary cell and a primary cell.

At step S1030, the first node (110) (e.g., terminal) can acquire synchronization for cell #1. Synchronization can be acquired by detecting a synchronization signal. Typically, synchronization is acquired before receiving system information, but since the system information for cell #1 is received from cell #2, synchronization acquisition for cell #1 can be performed after receiving the system information. For example, the terminal can acquire synchronization based on the system information. Alternatively, synchronization acquisition can be performed before step S1010.

At step S1050, the first node (110) may transmit a signal for accessing cell #1. For example, the signal may include a random access preamble. The structure of this signal and the resources (e.g., channels) for transmitting the signal may be identified through system information. Thereafter, at step S1070, the first node (110) and the second node (120) may perform an access procedure for cell #1 and communicate.

The procedure described with reference to FIG. 10 may be performed when the first node (110) initially connects to cell #1 of the second node (120). Alternatively, a similar procedure may be performed when the first node (110) hands over to cell #1 of the second node (120). However, in the case of handover, the system information of cell #1 may be received from a cell of a base station other than cell #2 of the second node (120).

Communications in the THz band are expected to experience extremely severe path loss, and to overcome this, terminals and base stations may be required to use very sharp beams. The use of sharp beams means that terminals and base stations must perform beam control in addition to beamforming, and the number of beams used increases significantly. Consequently, it takes a very long time to align the transmit and receive beams between the base station and terminals. Furthermore, if the beam alignment between the base station and terminals is misaligned due to movement or movement of the terminals, frequent re-alignment is required, which can lead to link instability.

FIG. 11 exemplarily illustrates a beam management procedure to which some examples of the present disclosure may be applied.

Although FIG. 11 illustrates an example of a procedure for searching and/or selecting beams for THz communication, this procedure is not limited to a THz environment and can also be applied to a 6G communication environment where THz communication is not applied.

Here, beam may be interpreted as other terms having equivalent technical meanings that can distinguish beams, such as 'spatial domain filter', 'spatial domain transmit filter', 'spatial domain receive filter', reference signal (RS) resource that distinguishes beams, SSB index, etc.

In step S1110, the second node (120) (e.g., base station) can set resources for beam management to the first node (110) (e.g., terminal). Here, the resources can include at least one of time-frequency resources, channels, and spatial resources (e.g., antenna ports). For example, the base station can utilize a beam search signal (BSS) that is transmitted spatially separated from an existing downlink signal/channel for beam search. Here, the BSS can be transmitted based on a dedicated port for beam search. The dedicated port can be a different port from a port for transmitting an existing downlink signal/channel (e.g., SSB, PDSCH (physical downlink shared channel), etc.). BSS is a term defined for convenience of explanation, and the technical concept according to the present embodiment is not limited to the term BSS itself. For example, a signal transmitted based on a dedicated port defined/set for beam search can be included in the technical concept according to the present embodiment.

In step S1130, the second node (120) (e.g., base station) transmits measurement signals using a plurality of transmission beams. For example, the measurement signals may include at least one of a reference signal and a synchronization signal. At this time, the measurement signals may be transmitted as many times as the number of beams that require measurement, and may also be transmitted in a multi-beam transmission method that forms a plurality of beams simultaneously to reduce sweeping time. Here, the multi-beam transmission may be performed based on at least one of a multi-panel, a sub-array, and a true time delay (TTD).

In step S1050, a first node (110) (e.g., a terminal) may transmit a feedback signal to a second node (120) (e.g., a base station). The feedback signal may indicate at least one beam selected by the terminal. The terminal may select at least one preferred beam based on the measurement signals received in step S1030.

In step S1070, the first node (110) and the second node (120) can perform communication. For example, the second node (120) can perform transmission to the first node (110) using the reception beam of the first node (110) selected in step S1050. If channel reciprocity is established, the transmission beam of the first node (110) can also be determined through steps S1030 and S1050, so that the transmission operation from the first node (110) can also be performed using a beam that has a reciprocal relationship with the beam selected in step S1050. If channel reciprocity is not established, a procedure including transmission of measurement signal(s) by the first node (110) and transmission of feedback signal(s) by the second node (120) may be performed first to determine the transmission beam of the first node (110).

non-terrestrial networks (NTN)

Figures 12 and 13 illustrate examples of NTN scenarios to which some examples of the present disclosure may be applied.

NTN can represent a network or network segment that uses radio frequency (RF) resources mounted on a satellite (or unmanned aerial system (UAS) platform).

Figure 12 shows an example of a typical scenario of NTN based on transparent payload, and Figure 13 shows an example of a typical scenario of NTN based on regenerative payload.

Referring to Figure 12, a satellite (or UAS platform) can establish a service link with a terminal. The satellite (or UAS platform) can be connected to a gateway via a feeder link. The satellite can be connected to a data network via the gateway. The beam footprint can refer to the area where the signal transmitted by the satellite can be received.

Referring to Figure 13, a satellite (or UAS platform) can establish a service link with a terminal. A satellite (or UAS platform) connected to a terminal can be connected to another satellite (or UAS platform) via an inter-satellite link (ISL). The other satellite (or UAS platform) can be connected to a gateway via a feeder link. Based on the regenerated payload, the satellite can be connected to a data network through another satellite and the gateway. If an ISL does not exist between the satellite and another satellite, a feeder link between the satellite and the gateway may be required.

Figures 12 and 13 are merely examples of NTN scenarios, and NTN can be implemented based on various scenarios. For example, a satellite (or UAS platform) can implement a transparent or regenerative (e.g., with onboard processing) payload. For example, a satellite (or UAS platform) can generate multiple beams across a designated service area depending on the field of view of the satellite (or UAS platform). For example, the field of view of the satellite (or UAS platform) can vary depending on the onboard antenna diagram and the minimum elevation angle.

For example, a transparent payload may include radio frequency filtering, frequency conversion, and amplification. Therefore, the waveform signal repeated by the payload may remain unchanged.

For example, a regenerative payload may include radio frequency filtering, frequency conversion and amplification, demodulation/decoding, switching and/or routing, and coding/modulation. For example, a regenerative payload may be substantially equivalent to mounting all or part of a base station function on a satellite (or UAS platform).

Integrated Sensing and Communication (ISAC)

Wireless sensing is a technology that uses radio frequencies to determine the instantaneous linear velocity, angle, distance (or range) of an object, and thus obtain information about the characteristics of the environment and/or objects within the environment. Because radio frequency sensing does not require a networked device to connect to the object, it can provide a service for object positioning without a device. The ability to obtain range, velocity, and angle information from radio frequency signals can enable a wide range of new capabilities, such as various object detection, object recognition (e.g., vehicles, humans, animals, UAVs), and high-precision localization, tracking, and activity recognition. Wireless sensing services can provide information to a variety of industries (e.g., drones, smart homes, V2X, factories, railways, public safety, etc.), enabling applications such as intruder detection, assisted vehicle steering and navigation, trajectory tracking, collision avoidance, traffic management, and health and traffic management. In some cases, wireless sensing can utilize non-3GPP type sensors (e.g., radar, cameras) to further support 3GPP-based sensing. For example, the operation of wireless sensing services, such as sensing operations, may depend on the transmission, reflection, and scattering of wireless sensing signals. Therefore, wireless sensing offers an opportunity to enhance existing communication systems from a communications network to a wireless communication and sensing network.

FIG. 14 illustrates examples of sensing operations to which some examples of the present disclosure may be applied.

Specifically, Fig. 14(a) shows an example of a monostatic sensing operation using a sensing receiver and a sensing transmitter located in the same location. Fig. 14(b) shows an example of a bistatic sensing operation using a sensing receiver and a sensing transmitter located in separate locations. A sensing signal transmitted from a sensing transmitter is reflected/scattered by a sensing object, and the sensing receiver can receive the signal, and extract/obtain sensing data based on the received signal. A sensing result can be generated/determined through appropriate processing of the sensing data. The sensing result can be provided to a trusted third-party entity/service outside the 3GPP system through an entity/service within the 3GPP system.

Low-power wake-up signal (LP-WUS) and low-power wake-up receiver (LP-WUR)

User devices or terminals in existing wireless communication systems consume tens of milliwatts of power even in RRC idle/inactive states, and hundreds of milliwatts in RRC connected states. To reduce power consumption and improve user experience, various methods are being discussed to extend battery life or improve energy efficiency.

Energy efficiency is even more important for devices with limited or no continuous energy sources (e.g., sensors, actuators, wearable devices, etc.). Power consumption can vary depending on the length of the wake-up interval (e.g., paging cycle). While longer extended-discontinuous reception (eDRX) cycles can be used to meet battery life requirements, this may not be suitable for low-latency applications (e.g., fire sensors and fire extinguisher actuators).

Terminals in existing wireless communication systems are required to wake up periodically, once per DRX cycle. This leads to power consumption even when there is no signal or data traffic for the terminal. If the terminal were to wake up only when triggered, such as by paging, power consumption could be significantly reduced. To achieve this, a wake-up signal can be used to trigger the main radio (MR), and a separate receiver that can monitor the wake-up signal with ultra-low power consumption can be used. The MR operates for data transmission and reception and can be turned off or set to deep sleep unless turned on.

In the present disclosure, MR refers to a transmit/receive module that operates on general wireless (e.g., NR) signals/channels, excluding signals/channels related to low-power wake-up. Additionally, a low-power-wake-up receiver (LP-WUR), which may also be referred to as LR, refers to a receiver module that operates to receive/process signals/channels related to low-power wake-up.

For LP-WUS and LP-WUR: IoT applications such as industrial wireless sensors, controllers, and actuators; wearable applications such as smartwatches, smart rings, and medical monitoring devices; and eMBB applications such as XR/smart glasses and smartphones.

For LP-WUS and LP-WUR, considering the benefits and scope of power savings and the resulting impact on system overhead and network energy, it is necessary to design an architecture for LP-WUR and define/change procedures and protocols for lower layers (e.g., L1 PHY) and upper layers (e.g., L2 MAC, L3 RRC, etc.) that support LP-WUS.

Accordingly, when sufficient relaxation is applied to MR radio resource management (RRM) measurements in RRC idle/inactive mode, it is expected that significantly reduced terminal power consumption can be achieved by triggering MR paging monitoring of the terminal using LP-WUS/WUR, compared to both with and without paging early indication (PEI) in I-DRX (idle-DRX). In addition, unlike the existing eDRX operation where paging monitoring is limited within the PTW (paging time window), it is expected that paging latency can be significantly reduced when monitoring paging after LP-WUS monitoring and MR wake-up, and thus terminal power consumption can be reduced. In addition, it is expected that reduced terminal power consumption can be achieved even in RRC connected mode when LP-WUS/WUR is used to trigger the terminal to monitor PDCCH in MR, and the MR enters a deep sleep state while LR is performing LP-WUS monitoring.

In addition, since the terminal must wake up at regular intervals to perform RRM measurements in addition to receiving paging through MR, it is expected that terminal power consumption can be reduced if some or all of the RRM measurements through MR can be offloaded to be performed through LR.

In this way, the longer the MR power off/sleep/deep sleep state is maintained, the more power consumption of the terminal can be reduced.

To make LP-WUS universally applicable to both RRC idle/inactive mode and RRC connection, OOK-based (e.g., OOK-1 and/or OOK-4) LP-WUS can be specified by superimposing OFDM sequences on OOK (on-off keying) symbols. In addition, the design of LP-WUS should ensure that the same information is conveyed regardless of the type of LP-WUR for idle/inactive operation, and that OFDM sequences can carry the information. In addition, duty-cycle based monitoring can be supported for LP-WUS.

Briefly explain the OOK-1 and OOK-4 methods.

Basically, the OOK scheme may include generating a multiple carrier-amplitude shift keying (MC-ASK) waveform. For example, an N-length LP-WUS and a typical wireless communication signal (e.g., a legacy NR signal) may be mapped to K subcarriers (e.g., SC#0 to SC#K-1). Specifically, an N-length LP-WUS signal may be mapped to SC#0 to SC#N-1, and a legacy NR signal may be mapped to SC#N to SC#K-1. The K subcarriers may be converted to a time domain signal through an inverse fast Fourier transform (IFFT), and a cyclic prefix (CP) may be appended to generate an OFDM symbol including the CP. Here, K is the size of the IFFT of CP-OFDMA (cyclic prefix-OFDMA), and N corresponds to the number of subcarriers (SCs) used in LP-WUS including a potential guard band.

In the OOK-1 scheme, information about a single bit can be signaled through a single OFDM symbol. OOK=1 can mean that all SCs are modulated, and OOK=0 can mean that all SCs have zero power (from a baseband perspective).

In the OOK-4 scheme, an M-bit OOK can be transformed in the time domain. For example, for an LP-WUS time domain signal of length N' samples for M bits, it is transformed into a frequency domain signal through DFT/LS (discrete Fourier transform/least square), and N-length OOK-1 LP-WUS subcarriers can be generated with or without signal truncation/modification (when N' is different from (greater than) N) or without (when N' is equal to N). This N-length LP-WUS signal and a general wireless communication signal (e.g., legacy NR signal) are mapped to K subcarriers (e.g., SC#0 to SC#K-1) (N' may be equal to K), and through IFFT+CP, one OFDM symbol including CP can be generated. Information for M bits can be signaled in this one OFDM symbol.

In the case of OOK-4, the Zadoff-Chu (ZC) sequence, M-sequence, and quadrature amplitude modulation (QAM) sequence before applying DFT/LS have a lot of phase variation, so a flat spectrum is expected and can provide robustness against frequency-selective fading. In addition, when DFT is applied to OOK-4 (e.g., when the value of M is 2 or greater), a frequency shift in the frequency domain or a -1/1 alternation in time may be applied to match the CP-OFDM generation. If the sequence(s) used for LP-WUS generation are repeated in the frequency domain, the diversity of MC-OOK and the robustness against frequency offset of MC-FSK (multiple carrier-frequency shift keying) can be improved.

In the present disclosure, a symbol modulated by OOK-1 or OOK-4 may be referred to as an OOK symbol (or OOK signal). Unless explicitly distinguished in the present disclosure, an OOK symbol/signal may mean a symbol/signal modulated by OOK-1 and/or OOK-4.

The synchronization signal (SS) used in LP-WUR may be referred to as LP-SS. For example, LP-SS may be an aperiodic signal transmitted as part of LP-WUS. In this case, LP-SS may or may not be transmitted additionally separately from LP-WUS. Alternatively, LP-SS may be a periodic signal transmitted separately from LP-WUS. Alternatively, LP-SS may include both an aperiodic signal transmitted as part of LP-WUS and a periodic signal transmitted separately from LP-WUS.

With respect to RRM measurements performed in LP-WUR, measurement metrics may include signal quality, signal power, LP-WUS/SS detection rate, etc. For RRM serving cell measurements performed by LP-WUR based on reference signals, LP-RSSI (received signal strength indicator) or energy detection, LP-RSRP, LP-SINR, LP-RSRQ, etc. may be defined. As these reference signals, SSB, LP-WUS-waveform sequence, LP-SS, etc. may be used.

Periodic LP-SS may also be used for RRM measurements by LP-WUR, coarse time synchronization of LP-WUR, coarse frequency synchronization of LP-WUR, etc.

If LP-WUR can receive existing primary synchronization signal (PSS)/secondary synchronization signal (SSS), which may be assisted by PBCH-DMRS (demodulation reference signal)/TRS (tracking reference signal), it may also use it for RRM measurement/time synchronization/frequency synchronization.

The coverage (e.g., reach/range) of a periodic LP-SS may be better than or equal to that of an LP-WUS.

For precise time/frequency synchronization, additional signals (e.g., a preamble) may be used before or as part of the LP-WUS.

As for the LP-SS period, 320ms can be supported. For example, periods of 80ms, 160ms, 640ms, 1280ms, 2560ms, 5120ms, and 10240ms may also be supported for LP-SS.

Additional synchronization signals for LP-SS may or may not be present. If present, additional synchronization signals may be configured for the terminal by signaling from the network, and/or may be predefined as present (without separate signaling) when certain conditions are met. For example, in OOK modulation for LP-WUS, additional synchronization signals may or may not be present depending on the value of M.

FIG. 15 and FIG. 16 are diagrams for explaining examples of the OOK method for an LP signal according to the present disclosure.

The LP signal may include LP-SS and/or LP-WUS. That is, the examples of FIGS. 15 and 16 may be applied to both LP-SS and LP-WUS.

Referring to FIG. 15, for example, among the total K subcarriers (SC#0, ..., SC#K-1), an LP signal of length N can be mapped to SC#0, SC#1, ..., SC#N-1, and a legacy signal of length K-N can be mapped to SC#N, SC#N+1, ..., SC#K-1. An OFDM symbol (including a CP) can be generated through an IFFT transform and CP addition for the K subcarriers. In an OOK-1 scheme such as the example of FIG. 15, information for a single bit can be signaled through one OFDM symbol. OOK=1 can mean that all SCs are modulated, and OOK=0 can mean that all SCs have zero power (from a baseband perspective).

Referring to Fig. 16, for example, when M=4 bits, an LP signal of length N' samples corresponding to a 4-bit sequence 1001 can be generated. The signal of length N' is converted into a frequency domain signal through DFT/LS, and, if necessary, truncation/modification can be applied so that N subcarriers of OOK-1 can be generated for the LP signal. This LP signal of length N and a legacy signal of length K-N can be mapped to K subcarriers, and through IFFT+CP, one OFDM symbol including CP can be generated. Information for M bits can be signaled through this one OFDM symbol.

Synchronization signal/PBCH (physical broadcast channel) block (SSB)

FIG. 17 is a diagram illustrating an example of an SSB time resource to which the present disclosure can be applied.

An SSB burst defined in an NR system may include SSB time resources. Fig. 17(a) shows examples of SSB time resource locations according to subcarrier spacing (SCS) in frequency range 1 (FR1), which corresponds to a frequency band of 6 GHz or less or from 410 MHz to 7125 MHz. Fig. 17(b) shows examples of SSB time resource locations according to SCS in frequency range 2 (FR2) (or mmWave band), which corresponds to a frequency band of 6 GHz or more or from 24.25 GHz to 52.6 GHz.

Case A - For 15 kHz SCS in FR1, the first symbol of the candidate SSBs can correspond to the index of {2,8} + 14*n. For operation without shared spectrum channel access, n=0, 1 for carrier frequencies below 3 GHz, and n=0, 1, 2, 3 for carrier frequencies within FR1 above 3 GHz. For operation supporting shared spectrum channel access, n=0, 1, 2, 3, 4.

Case B - For the first case of 30 kHz SCS in FR1, the first symbol of the candidate SSBs can correspond to the index of {4,8,16,20} + 28*n. For carrier frequencies below 3 GHz, n=0, and for carrier frequencies within FR1 above 3 GHz, n=0, 1.

Case C - In the second case of 30 kHz SCS in FR1, the first symbol of the candidate SSBs may correspond to the index of {2,8} + 14*n. For operation without shared spectrum channel access, for paired spectrum operation, n=0, 1 for carrier frequencies below 3 GHz, and n=0, 1, 2, 3 for carrier frequencies within FR1 above 3 GHz within FR1. For unpaired spectrum operation, n=0, 1 for carrier frequencies below 1.88 GHz, and n=0, 1, 2, 3 for carrier frequencies within FR1 above 1.88 GHz within FR1. For operation supporting shared spectrum channel access, n=0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

Case D - For 120 kHz SCS in FR2, the first symbol of the candidate SSBs can correspond to the index {4,8,16,20} + 28*n. For carrier frequencies within FR2, n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18.

Case E - For 240kHz SCS in FR2, the first symbol of the candidate SSBs can correspond to the index {8,12,16,20,32,36,40,44} + 56*n. For carrier frequencies within FR2-1, n=0, 1, 2, 3, 5, 6, 7, 8.

Case F - For 480 kHz SCS in FR2, the first symbol of the candidate SSBs can correspond to the index of {2, 9} + 14*n. For carrier frequencies within FR2-2, n = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31.

Case G - For 960 kHz SCS in FR2, the first symbol of the candidate SSBs can correspond to the index of {2, 9} + 14*n. For carrier frequencies within FR2-2, n = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31.

LP-SS transmission/reception using multiple LP-SS sequence candidates based on cyclic shift

In this disclosure, a method for generating and setting multiple LP-SS sequence candidates using cyclic shift for LP-SS and transmitting/receiving LP-SS based on the generated LP-SS sequence candidates is described.

While the following description describes a specific wireless communication system (e.g., an NR system) as an example of a wireless communication system to which the examples of the present disclosure apply, the scope of application of the present disclosure is not limited to a specific wireless communication system. The examples of the present disclosure can be applied to any wireless communication system within the scope that maintains the characteristics of the invention.

In order to reduce the number of times a terminal wakes up the MR, it is necessary to receive a synchronization signal (e.g., LP-SS) in advance or simultaneously with the wake-up signal (e.g., LP-WUS). This disclosure describes a method for generating a sequence for LP-SS and a related setting method.

In conventional wireless communication systems, a base station can generate and transmit OFDM signals to send control/data signals to a terminal. In this case, the terminal requires relatively accurate synchronization to receive the OFDM signal, and for this purpose, a coherent detection and demodulation-based receiver can be utilized. Such a receiver may require power-consuming RF modules such as a bandpass filter (BPF), fast Fourier transform (FFT), and local oscillator, as well as a baseband module. In LP-WUR that receives LP-WUS, a non-coherent detection and demodulation-based receiver can be utilized instead of the power-consuming modules mentioned above to receive signals at low power. As an LP-WUS signal for such a low-power receiver, an OOK-1/OOK-4 signal (with or without an overlaid OFDM sequence) can be used. These OOK-1/OOK-4 signals are used as MC-OOK signals to make full use of the OFDM transmitter of the base station, and the signal generation method and maximum number of bits that can be transmitted may vary depending on the option.

Additionally, receiver capabilities may vary depending on the WUR type. For example, some WURs may have the capability to detect OFDM sequences overlaid on OOK signals, while others may not. Supporting OFDM sequences overlaid on OOK signals may increase coverage or allow additional bits to be transmitted.

In this disclosure, the transmission scheme of LP-SS is classified as follows:

Transmission method 1: LP-SS is transmitted as part of LP-WUS and corresponds to a signal transmitted aperiodically;

Transmission method 2: LP-SS is transmitted separately from LP-WUS and corresponds to a signal that is transmitted periodically;

Transmission method 3: By applying both transmission methods 1 and 2, LP-SS is transmitted aperiodically as part of LP-WUS, and also periodically separately from LP-WUS.

The aperiodic LP-SS described above may be transmitted as a part of the LP-WUS or in the form of a preamble. The aperiodic LP-SS may be transmitted together with (or included in) the LP-WUS when there is a transmission of the LP-WUS, but the aperiodic LP-SS may not be transmitted when there is no transmission of the LP-WUS. The LP-WUS may be transmitted to the terminal when an event that requires waking up the MR of the terminal occurs. That is, the LP-WUS is transmitted based on an event, and the aperiodic LP-SS may be transmitted together with the LP-WUS when the LP-WUS is transmitted based on such an event.

The waveform applied to LP-SS in the present disclosure may include the following options.

Option 1: OOK-1

Option 2: OOK-4 with M=1, 2, 4, or 8

Multiple binary LP-SS sequences can be specified for an ON-OFF pattern. For example, the LP-SS sequence used in a cell may be configured by the network to the terminal, and/or may be determined according to predefined rules without separate signaling. Multiple LP-SS sequences can be used to distinguish LP-SSs from different cells.

FIG. 18 is a drawing for explaining an example of a method performed by a terminal according to the present disclosure.

In step S1810, the terminal can obtain information related to a sequence overlaid on a synchronization signal.

In some examples, information related to the overlaid sequence may be signaled/configured from the network to the terminal. For example, information related to the overlaid sequence may include a sequence index and/or a cyclic shift (CS) value. For example, the sequence index may correspond to a root index, a scrambling identifier, etc.

In some examples, information related to the overlaid sequence may correspond to information previously provided to the terminal. For example, information related to the overlaid sequence may include a physical cell identifier. For example, the terminal may derive a specific sequence based on the physical cell identifier. The relationship between the physical cell identifier and the properties of a specific sequence among the overlaid sequences may be predefined. For example, the terminal may derive the sequence index and/or CS value of the overlaid sequence based on the physical cell identifier.

In some examples, the overlaid sequence may be an OFDM sequence based on the OOK modulation technique.

In some examples, the synchronization signal may be a low power-synchronization signal (LP-SS), which is received by a low power-wake up receiver (LP-WUR) of the terminal.

In step S1820, the terminal can receive a synchronization signal from the network based on information related to the overlaid sequence.

In some examples, one of the sequence candidates can be identified based on information related to the overlaid sequence. Accordingly, assuming that the identified sequence is overlaid on the synchronization signal, the terminal can receive the synchronization signal.

In some examples, a set of sequence candidates may be predefined. For example, different sequence candidates within the set may be distinguished by sequence indices and/or CS values.

The method described in the example of FIG. 18 may be performed by the wireless device (200) of FIG. 3 corresponding to the first node (110) of FIG. 2 described above. For example, one or more processors (202) of the wireless device (200) of FIG. 3 may be configured to obtain information related to a sequence overlaid on a synchronization signal, and receive the synchronization signal from a network via one or more transceivers (206) based on the information related to the overlaid sequence. For example, the one or more transceivers (206) may include MR and LP-WUR. Furthermore, one or more memories (204) of the wireless device (200) may store instructions for performing the method described in the example of FIG. 18 or the examples described below when executed by one or more processors (202).

FIG. 19 is a drawing illustrating an example of a method performed by a base station according to the present disclosure.

In step S1910, the base station may provide the terminal with information related to the sequence overlaid on the synchronization signal.

In step S1920, the base station may transmit a synchronization signal to the terminal based on information related to the overlaid sequence. For example, the base station may generate a synchronization signal overlaid with a specific sequence based on information related to the overlaid sequence and transmit the generated synchronization signal to the terminal.

Specific features regarding information related to the overlaid sequence, the set of overlaid sequence candidates, and a specific sequence among the set are identical to the description referring to the example of Fig. 18, so redundant descriptions are omitted.

The method described in the example of FIG. 19 may be performed by the wireless device (200) of FIG. 3 corresponding to the second node (120) of FIG. 2 described above. For example, one or more processors (202) of the wireless device (200) of FIG. 3 may be configured to provide information related to a sequence overlaid on a synchronization signal to a terminal via one or more transceivers (206), and to transmit a synchronization signal based on the information related to the overlaid sequence to the terminal via one or more transceivers (206). The terminal to which the wireless device (200) transmits the synchronization signal may be a terminal that has notified the base station that it has the LP-WUR capability or a terminal that the base station knows in advance. Furthermore, one or more memories (204) of the wireless device (200) may store commands for performing the method described in the example of FIG. 19 or the examples described below when executed by one or more processors (202).

In the present disclosure, setting or pre-setting specific information for a terminal may mean that the specific information is provided by upper layer (e.g., L3 RRC) signaling from the network. In the present disclosure, indicating specific information for a terminal may mean that the specific information is provided by lower layer (e.g., L2 MAC or L1 PDCCH/DCI) signaling from the network. For example, if information A including candidate values a1, a2, a3, ... is set for a terminal (via upper layer signaling), and a1 among them is indicated to the terminal (via lower layer signaling), the terminal can operate based on the value a1. In the present disclosure, pre-defining specific information may mean that the network and the terminal each assume or know in advance that the specific information exists/is applied without signaling between the network and the terminal.

Below, we define a number of LP-SS sequence candidates based on cyclic shift, and describe various examples of the present disclosure for transmitting/receiving LP-SS based on the same.

Although the examples described below briefly refer to LP-SS sequences, the various examples of LP-SS sequences in the examples described below are not limited to being applied to OOK sequences (i.e., binary sequences) of LP-SS, and can be equally applied to OFDM sequences overlaid on LP-SS. For example, for an overlaid sequence in the frequency domain applied to LP-SS, the sequence index and/or cyclic shift value may be set/indicated/determined through higher layer signaling or pre-defined rules, as in the examples described below. For example, for an overlaid sequence in the time domain applied to LP-SS, the sequence index and/or cyclic shift value may be set/indicated/determined through higher layer signaling or pre-defined rules, as in the examples described below.

Example 1

This embodiment relates to a method for setting an LP-SS sequence to a terminal through upper layer signaling.

For LP-SS related to synchronization and RRM measurement for smooth reception of LP-WUS, multiple sequences may be supported to distinguish the cell in which the LP-SS is transmitted. Here, the sequences of the LP-SS may be configured/defined in various ways. For example, the sequence of the LP-SS may be configured through higher layer signaling (e.g., RRC signaling or SIB).

For example, information related to the sequence of LP-SS can be set/instructed to the terminal from the base station through upper layer signaling (e.g., RRC signaling or SIB), and examples of information related to the sequence of LP-SS are described below.

Example 1-1

The sequence index of LP-SS can be set/indicated to the terminal through upper layer signaling.

For example, a base station can directly set/instruct a terminal to set/indicate a sequence index (e.g., different for each cell). Here, the sequences that can be set (i.e., sequence candidates) can be predefined. That is, the base station and the terminal can know the same sequence candidates without mutual signaling. Alternatively, the sequence candidates can be defined through predefined rules. For example, the base station and the terminal can know the same rule for deriving sequence candidates without mutual signaling, and by applying common information to the rule, the base station and the terminal can derive the same sequence candidates.

For example, in the case of the existing primary synchronization signal (PSS) and secondary synchronization signal (SSS), the sequence candidates are predefined, or can be derived through predefined rules (e.g., modulo operation) based on the cell ID. In the case of PSS, it can be generated using one of three different sequences, namely, x0(n), x1(n), and x2(n). Here, x0(n)=x(n), x1(n)=x(n+43*N ² _ID mod127), and x2(n)=x(n+86*N ² _ID mod127). N ² _ID can have one of the values 0, 1, 2, n=0, ..., 126, and x(n) is a 127-length m-sequence (e.g., an m-sequence defined as x(6) x(5) x(4) x(3) x(2) x(1), with initial value [1 1 1 0 1 1 0], and obeying x(n)=x(n-7)+x(n-3)mod2).

When defining sequence candidates through pre-defined rules based on cell ID for LP-SS, a result value can be produced by applying a modulo operation with the cell ID and the set/indicated sequence length, and sequence candidates can be derived by applying a cyclic shift to the set/indicated sequence for a multiple of the produced result value.

LP-SS can also be expressed similarly to the existing PSS. That is, in the case of LP-SS, different sequences can be distinguished based on cell IDs, such as physical cell identifiers, or based on the result of an operation on the cell ID.

LP-SS sequence candidates may be distinguished based on a scrambling identifier (ID) applied to the sequence of a downlink reference signal (RS) or a root (sequence) index applied to the sequence of an uplink RS. Alternatively, the sequence candidates may be distinguished from each other by a cyclic shift.

For example, as an example of a downlink signal, the PDCCH DMRS can be initialized according to the pseudo-random sequence generator c _init =(2 ¹⁷ (N ^slot _symb n ^u _s,f +l+1)(2N _ID +1)+2N _ID )mod2 ³¹ , where l is the OFDM symbol index and n ^u _s,f corresponds to the slot index within the frame. In this case, the sequences can be distinguished from each other by the scrambling ID N _ID .

For example, as an example of an uplink signal, a random access preamble can be given as x _u (i) = ej(πui(i+1)/L _RA ), where L _RA corresponds to the length of the RACH (random access channel) preamble. In this case, different preambles (sequences) can be distinguished based on the root (sequence) index u.

Likewise, in the case of LP-SS, different sequences can be distinguished based on the scrambling ID and/or the root (sequence) index and/or the index.

As a further example, sequences for LP-SS can be distinguished through a combination of the two methods described above (e.g., a combination of a scrambling ID and a cyclic shift value, or a combination of a root index and a cyclic shift value).

For example, it can be assumed that the number of LP-SS sequences that can be distinguished through the entire scrambling ID or root index is N in total, and the number of LP-SS sequences that can be distinguished through the cyclic shift value is M in total. In this case, the LP-SS sequence candidates can be expressed as S{n,m}, where n is 0,...,N-1, and m is 0,...,M-1. The number of LP-SS sequences that can be distinguished through the index/ID and the cyclic shift value is L=N*M in total. Alternatively, if the LP-SS sequence candidates are distinguished only by the scrambling ID or the root index, a total of N sequences S{n} can be defined. Alternatively, if the LP-SS sequence candidates are distinguished only by the cyclic shift value, a total of M sequences S{m} can be defined.

Among the sequence candidates defined in this way, the sequence index can be set/indicated to the terminal through upper layer signaling (e.g., RRC signaling or SIB). For example, when the number of LP-SS sequences used in a low-power communication system is 4 (sequence candidates = {sequence #0, sequence #1, sequence #2, sequence #3}), the sequence index can be set/indicated through upper layer signaling as shown in Table 1. Here, the number of LP-SS sequences, 4, is only exemplary, and the examples of the present disclosure can be applied to a greater or lesser number.

Index Sequence 0 Sequence #0 1 Sequence #1 2 Sequence #2 3 Sequence #3

Example 1-2

The cyclic shift (CS) value of LP-SS can be set/indicated to the terminal through upper layer signaling.

In Example 1-1, it is assumed that LP-SS sequence candidates are predefined or derived according to predefined rules, but in this Example 1-2, multiple sequence candidates can be derived by applying different cyclic shift values to a single sequence (such single sequence can be predefined, derived according to predefined rules, or set through upper layer signaling).

For example, when the number of LP-SS sequence candidates used in a low-power communication system is 4, the cyclic shift value can be set/indicated to the terminal through upper layer signaling as shown in Table 2. Accordingly, the terminal can use a sequence that applies the set/indicated cyclic shift value to a sequence that it already knows. Here, the number of LP-SS sequences, 4, is only exemplary, and the examples of the present disclosure can be applied to a greater or lesser number.

Index Circular shift value 0 0 1 K 2 2K 3 3K

The parameter K in Table 2 may be set/indicated as 1/2, 1/4, ... of the sequence length, or may be set/indicated as one of the cyclic shift values. For example, when indicating a cyclic shift (CS) value, the parameter K may be the minimum value among the candidates for the CS value, or the value of the parameter K may be set/indicated directly to the terminal through upper layer signaling.

As in the example in Table 3, the CS value corresponding to the index set/instructed by the base station to the terminal may be applied. That is, the CS value may be set/instructed directly, rather than indirectly set/instructed through the parameter K.

Index Circular shift value 0 0 1 Circular shift value #0 2 Circular Shift Value #1 3 Circular shift value #2

FIG. 20 is a diagram showing an example of a case where a cyclic shift value K is applied to a sequence of length L according to the present disclosure.

In Fig. 20, a sequence indicated as SEQ1 corresponds to a sequence having a total of L elements at positions #0, #1, ..., #L-2, #L-1. A sequence to which a cyclic shift value K is applied to SEQ1 is indicated as SEQ2. Since each element of SEQ1 is shifted by K, the value at position #0 of SEQ1 corresponds to the value at position #K of SEQ2, and the value at position #1 of SEQ2 corresponds to the value at position #K+1 of SEQ2. The value at position #L-1 of SEQ1 cyclically corresponds to the value at position #K-1 of SEQ2, and the value at position #L-2 of SEQ1 cyclically corresponds to the value at position #K-2 of SEQ2.

The cyclic shift value can be flexibly set/instructed to the terminal by the base station considering the channel environment or LP-WUR type, etc. For example, in an environment where the channel delay spread is short, the sequence can be detected smoothly even with a short cyclic shift value, so the parameter K value can be set short (for example, to 1/4 of the sequence length). For example, if different CS values are required depending on the LP-WUR type, single or multiple CS values can be reported to the base station through the terminal capability report. Alternatively, the base station can set/instruct the terminal differently for the K value in Table 2 depending on the LP-WUR type (for example, envelope detection-based LP-WUR type, OFDM-based LP-WUR type, etc.), so that the terminal can apply different K values for each LP-WUR type (i.e., each terminal can apply a different K value even if the base station sets/instructs the same index).

As an additional example, the cyclic shift value may be set/indicated through a pre-defined rule depending on the subcarrier spacing. For example, if the cyclic shift value applied to an LP-SS with a subcarrier spacing of 30 kHz is K, the cyclic shift value used in an LP-SS with a subcarrier spacing of 15 kHz may be set/indicated as 2K or K/2. Here, it may be considered that an LP-SS with a subcarrier spacing of 15 kHz may have a longer cyclic prefix (CP) duration than an LP-SS with a subcarrier spacing of 30 kHz. Different CP values may also be applied to examples of other subcarrier spacings.

Example 1-3

The sequence index and cyclic shift index (or combination thereof) of LP-SS can be set/indicated to the terminal through upper layer signaling.

This embodiment may correspond to a method of applying both the aforementioned embodiments 1-1 and 1-2. For example, the base station may set/instruct the terminal to set/instruct the index of the cyclic shift value described in embodiment 1-2 together with the sequence index of the sequence candidate described in embodiment 1-1. For example, for LP-SS used in a low-power communication system, if the number of sequences distinguished by the sequence index is 4 and the number of sequences distinguished by the cyclic shift value is 2, a total of 8 LP-SS sequences may be distinguished depending on their combination. For example, as shown in Table 4, by assigning different indices to different combinations of sequence indices and cyclic shift values, and the base station setting/instructing the index for the LP-SS sequence to the terminal through upper layer signaling, the terminal can derive the LP-SS sequence by applying the set/instructed sequence index and cyclic shift value. Table 4 is only an example; various combinations of sequence indices and circular shift values with different numbers/values can be defined and used.

Index Sequence Circular shift value 0 Sequence #0 0 1 Sequence #0 K 2 Sequence #1 0 3 Sequence #1 K 4 Sequence #2 0 5 Sequence #2 K 6 Sequence #3 0 7 Sequence #3 K

For example, in the example of Table 4, a combination of sequence index and circular shift value can be set/indicated, and the sequence index and circular shift value can also be set/indicated separately/independently, as in the examples of Table 1, Table 2, and Table 3.

In the example of Table 4, the parameter K may be set/indicated as 1/2, 1/4, ... of the sequence length, similar to Embodiment 1-2, or may be set/indicated as one of the CS values. The base station may flexibly set/indicate the cyclic shift value by considering the channel environment/LP-WUR type, etc.

If only one of the two parameters for LP-SS (i.e., the parameter for the sequence index and the parameter for the cyclic shift value) is set/instructed to the terminal, the terminal may derive and apply the parameter based on a pre-defined rule as in Example 2 described below for the remaining parameter.

FIG. 21 is a drawing for explaining an example of terminal and base station operations according to the present disclosure.

In step S2110, the base station can set/instruct the terminal to set/instruct an index for one of the sequence candidates, either predefined as in the examples described above (e.g., sequence #0, sequence #1) or sequence candidates derived based on predefined rules (e.g., sequence #0, sequence #1), according to the base station environment. Additionally, in addition to the sequence index, the base station can also set/instruct the terminal to set/instruct a cyclic shift value to be applied to the sequence according to the channel environment or the LP-WUR type of the terminal. For example, for a terminal with an LP-WUR type that uses a relatively poor-performance oscillator or a channel environment with a very large delay spread, providing a small cyclic shift value may increase the MDR (miss detection rate) or FAR (false alarm rate). Taking these points into consideration, the base station can determine the LP-SS sequence setting to be set/instructed to the terminal.

In step S2120, the base station can set/instruct the terminal to the LP-SS sequence index (or sequence index and cyclic shift value) determined in step S2110 through upper layer signaling.

In step S2130, the terminal can determine an LP-SS sequence index (and cyclic shift value) set/indicated by the base station based on information included in higher layer signaling (e.g., RRC signaling or SIB). For example, among sequence candidates (e.g., sequence #0, sequence #1) that are pre-defined or derived according to a pre-defined rule, the terminal can determine one sequence (e.g., sequence #0) set/indicated by higher layer signaling, determine a CS value (e.g., 0) to be applied to the sequence, and determine/generate an LP-SS sequence to be received based on a combination of these parameters.

In step S2140, the base station can transmit (or broadcast) the LP-SS sequence generated according to the sequence index (and cyclic shift value) determined in step S2110 to one or more terminals.

In step S2150, the terminal can receive LP-SS based on the sequence index (and cyclic shift value) determined in step S2130.

Example 2

This embodiment relates to a method for setting an LP-SS sequence through pre-defined rules.

In the above-described embodiment 1, an LP-SS sequence is determined/generated based on a sequence index and/or a cyclic shift value set/indicated through upper layer signaling (e.g., RRC signaling or SIB). That is, the base station can directly provide the terminal with the configuration for the LP-SS. In contrast, in the present embodiment 2, an LP-SS sequence is determined/generated based on a sequence index and/or a cyclic shift value derived through a pre-defined rule. That is, through a pre-defined rule between the base station and the terminal, the base station can determine/generate and transmit an LP-SS sequence to be transmitted based on the assumption that the terminal knows the rule, and the terminal can determine/generate an LP-SS sequence to be transmitted by the base station to itself.

Example 2-1

LP-SS sequence indices can be derived by modulo operations, where mod(A,B) or A mod B means the remainder when A is divided by B.

For example, a cell-specific LP-SS sequence can be derived through a modulo operation of two parameters. For example, the modulo operation can be applied based on the physical cell ID and the number of LP-SS sequences that can be used in the low-power communication system. For example, the sequence index can be derived based on the formula sequence index = mod(physical cell ID, number of LP-SS sequences).

Here, the sequence candidates that can be defined through the sequence index may be pre-defined, or may be defined through pre-defined rules (e.g., polynomial settings in sequence generation through physical cell ID). For example, assuming that the number of LP-SS sequences used in a low-power communication system is 4 and the physical cell ID is 101, the sequence index can be derived as 1 according to the above-described formula.

Here, assuming that the sequence candidates are {sequence #0, sequence #1, sequence #2, sequence #3}, the terminal can determine that sequence #1 corresponding to sequence index 1 will be transmitted from the base station as shown in Table 5.

Sequence index Sequence 0 Sequence #0 1 Sequence #1 2 Sequence #2 3 Sequence #3

In the example of Table 5, the number of LP-SS sequences used in the low-power communication system, 4, is merely exemplary, and the examples of the present disclosure may be applied to a greater or lesser number. In addition, the LP-SS sequences may be distinguished based on the scrambling ID applied to the sequence of the downlink reference signal or the root (sequence) index applied to the sequence of the uplink reference signal. Accordingly, the sequence index may correspond to the scrambling ID or the root (sequence) index. Alternatively, the sequences may be distinguished based on the cyclic shift value, and such distinguished sequences may be mapped to different sequence indices. Alternatively, distinct combinations of the scrambling ID and the cyclic shift value may correspond to different sequence indices, or distinct combinations of the root (sequence) index and the cyclic shift value may correspond to different sequence indices.

Example 2-2

The cyclic shift value of the LP-SS sequence can be derived by modulo operation.

The terminal can derive the cyclic shift value applied to the LP-SS by itself through pre-defined rules. For example, the first formula can be defined as: Cyclic shift value = K * mod (physical cell ID, number of cyclic shift value candidates). For example, the second formula can be defined as: Cyclic shift value = K * floor { mod (physical cell ID, floor (seq_length / K)) } (wherein floor (x) is the largest integer less than or equal to x). Here, the parameter K can be set/indicated as 1/2, 1/4, ... of the sequence length (seq_length), or can be set/indicated as one of the CS values. The terminal can derive the cyclic shift value based on the first formula or the second formula.

Specifically, in order to apply cell-specific LP-SS sequences, cyclic shift values can be used to distinguish sequences on a cell-by-cell basis. In the first equation, the number of cyclic shift values available in a low-power communication system and the parameter K can be used to determine the cyclic shift value in combination with the physical cell ID. In the second equation, the length of the LP-SS sequence and the parameter K can be used to determine the cyclic shift value in combination with the physical cell ID.

Here, the cyclic shift value can be adjusted by the base station flexibly setting/instructing the parameter K by considering the channel environment or the LP-WUR type, etc. In this regard, the parameter called the number of cyclic shift value candidates used in the first formula means the number of cyclic shift values that can be used in the low-power communication system. The parameter called seq_length used in the second formula means the length of the sequence used in the LP-SS. Here, the number of cyclic shift value candidates and/or seq_legnth can be determined by the base station based on the terminal capability report, or the base station can arbitrarily set/instruct the terminal through a higher layer signaling (e.g., RRC signaling or SIB). Alternatively, different values can be applied to the number of cyclic shift value candidates and/or seq_legnth depending on the LP-WUR type (e.g., envelope detection LP-WUR, OFDM-based LP-WUR, etc.).

The sequence to which the circular shift is applied may be a pre-defined sequence.

Example 2-3

The sequence index and cyclic shift value of the LP-SS sequence can be derived by modulo operation.

A method for determining two parameters for LP-SS (i.e., sequence index and cyclic shift value) through modulo operation may correspond to a combination of Embodiments 2-1 and 2-2. For example, a sequence index may be determined according to the formula of Embodiment 2-1, and a cyclic shift value to be applied to the corresponding sequence may be determined according to the first or second formula of Embodiment 2-2. Accordingly, an LP-SS sequence to be transmitted by a base station and received by a terminal may be determined identically by both the base station and the terminal.

For example, it can be assumed that the number of LP-SS sequences that can be determined through the sequence index (i.e., through Embodiment 2-1) is 2, and the number of cyclic shift values that can be determined through the cyclic shift value (i.e., through Embodiment 2-2) is 2. Accordingly, the number of LP-SS sequence candidates that can be derived at the base station/terminal is 4 depending on the combination of the candidate number of sequence indexes and the candidate number of cyclic shifts. The terminal can derive the sequence index and the cyclic shift value based on the above-described formula in order to determine one sequence among the sequence candidates through a pre-defined rule. Accordingly, the terminal can finally determine the LP-SS sequence to be received from the base station and attempt LP-SS reception based on the determined LP-SS sequence.

FIG. 22 is a drawing for explaining another example of terminal and base station operations according to the present disclosure.

In step S2210, the base station may determine the sequence index and cyclic shift value of the LP-SS according to a pre-defined rule (e.g., through a modulo operation based on the physical cell identifier value).

In step S2220, the terminal, like the base station, can determine the sequence index and cyclic shift value of the LP-SS according to pre-defined rules (e.g., through modulo operation based on the physical cell identifier value).

In step S2230, the base station can transmit (or broadcast) the LP-SS sequence generated according to the sequence index and cyclic shift value determined in step S2210 to one or more terminals.

In step S2240, the terminal can receive LP-SS based on the sequence index and cyclic shift value determined in step S2220.

Example 3

Some of the LP-SS sequence parameters are set/instructed from the base station to the terminal through upper layer signaling, and other parts of the LP-SS sequence parameters can be derived/determined by the base station and the terminal respectively (without signaling between the base station and the terminal) according to pre-defined rules.

The LP-SS sequence parameters may include a sequence index (e.g., a root index, a scrambling ID, etc.) and a cyclic shift value. The first parameter may be set/indicated to the terminal through upper layer signaling as in Embodiment 1, and the second parameter may be determined identically by the base station and the terminal according to a pre-defined rule. The first parameter may be a sequence index and the second parameter may be a cyclic shift value. Alternatively, the first parameter may be a cyclic shift value and the second parameter may be a sequence index.

Example 3-1

The sequence index can be set/indicated via upper layer signaling, and the cyclic shift value can be determined via pre-defined rules.

The terminal can set/receive a sequence index through upper layer signaling (e.g., RRC signaling or SIB) (according to embodiment 1) and determine a cyclic shift value through a pre-defined rule (according to embodiment 2). Accordingly, the terminal can derive/determine an LP-SS sequence to be received from the base station.

The base station can only set/instruct the terminal to the sequence index, and both the base station and the terminal can perform LP-SS sequence transmission/reception by deriving the remaining parameter, the cyclic shift value, through a pre-defined rule.

As mentioned above, the sequence index indicated through the upper layer signaling may be one of the indices corresponding to the predefined sequence candidates or the sequence candidates defined through the predefined rules. The candidates for the cyclic shift value may be set/indicated by the base station through the parameter K depending on the channel environment or the LP-WUR type, or may be predefined.

Example 3-2

The cyclic shift value can be set/indicated via upper layer signaling, and the sequence index can be determined via pre-defined rules.

The terminal can set/be instructed to set/be instructed to set a cyclic shift value through upper layer signaling (e.g., RRC signaling or SIB) (according to embodiment 1) and determine a sequence index through a pre-defined rule (according to embodiment 2). Accordingly, the terminal can derive/determine an LP-SS sequence to be received from the base station.

The base station can only set/instruct the terminal to the cyclic shift value, and both the base station and the terminal can perform LP-SS sequence transmission/reception by deriving the remaining parameter, the sequence index, through pre-defined rules.

As described above, the sequence index derived through the predefined rule may be one of the indices corresponding to the predefined sequence candidates or the sequence candidates defined through the predefined rule. The candidates for the cyclic shift value may also be set/indicated by the base station through the parameter K depending on the channel environment or the LP-WUR type.

In the examples described above, if the LP-SS sequence parameter defined to be provided to the terminal through upper layer signaling from the base station is not provided to the terminal, the terminal may derive and apply the parameter based on a predefined rule. For example, if the base station and terminal operations are defined such that a first parameter is signaled and a second parameter is determined according to a predefined rule, if signaling for the first parameter is not provided, the terminal may derive and apply the first parameter according to the predefined rule.

FIG. 23 is a drawing for explaining another example of terminal and base station operations according to the present disclosure.

In step S2310, the base station may determine the first parameter of the LP-SS sequence through a pre-defined rule (e.g., modulo operation based on the physical cell ID).

In step S2320, the terminal may determine the first parameter of the LP-SS sequence through a pre-defined rule (e.g., modulo operation based on the physical cell ID).

In step S2330, the base station may determine the second parameter of the LP-SS sequence by considering the channel environment or the LP-WUR type, and in step S2340, provide the second parameter to the terminal through upper layer signaling (e.g., RRC signaling or SIB).

In step S2350, the terminal may determine the value of the second parameter set/instructed by the base station based on information included in upper layer signaling (e.g., RRC signaling or SIB).

In step S2360, the base station can transmit (or broadcast) the LP-SS sequence generated according to the first parameter determined in step S2310 and the second parameter determined in step S2330 to one or more terminals.

In step S2370, the terminal can receive LP-SS based on the first parameter determined in step S2320 and the second parameter determined in step S2350.

In the example of FIG. 23, the first parameter may be a sequence index and the second parameter may be a cyclic shift value. Alternatively, the first parameter may be a cyclic shift value and the second parameter may be a sequence index.

The OOK-1/OOK-4 signals used as LP-WUS/LP-SS described in this disclosure can be used in various low-power communication systems. For example, the Internet of Things (IoT) has recently attracted much attention in the wireless communication world. By reducing the size, complexity, and power consumption of IoT devices and installing and connecting hundreds of billions to trillions of IoT devices, application to various application fields can be enabled. Ambient IoT communication is also being discussed. For example, the generation/configuration of low-power OOK signals/sequences described in this disclosure can be applied to various low-power communication systems, such as ambient IoT communication systems.

The embodiments described above are combinations of components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, it is also possible to form embodiments of the present disclosure by combining some components and/or features. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is self-evident that claims that do not have an explicit citation relationship in the patent claims may be combined to form embodiments or incorporated as new claims through post-application amendments.

It will be apparent to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the essential characteristics thereof. Therefore, the above detailed description should not be construed as limiting in any respect, but rather as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the scope of equivalents of the present disclosure are intended to be included within the scope of the present disclosure.

The scope of the present disclosure includes software or machine-executable instructions (e.g., an operating system, an application, firmware, a program, etc.) that cause operations according to the methods of various embodiments to be executed on a device or a computer, and a non-transitory computer-readable medium having such software or instructions stored thereon and executable on the device or computer. Instructions that can be used to program a processing system to perform the features described in the present disclosure can be stored on/in a storage medium or a computer-readable storage medium, and a computer program product including such a storage medium can be used to implement the features described in the present disclosure. The storage medium can include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid state memory devices, and can include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. The memory optionally includes one or more storage devices remotely located from the processor(s). The memory or, alternatively, the non-volatile memory device(s) within the memory comprise a non-transitory computer-readable storage medium. The features described in this disclosure may be incorporated into software and/or firmware stored on any of the machine-readable media, which may control the hardware of the processing system and allow the processing system to interact with other mechanisms that utilize results according to embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments/containers.

Here, the wireless communication technology implemented in the device of the present disclosure may include not only LTE, NR, and 6G, but also Narrowband Internet of Things for low-power communication. For example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology and may be implemented with standards such as LTE Cat NB1 and/or LTE Cat NB2, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the device of the present disclosure may perform communication based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and may be called by various names such as eMTC (enhanced Machine Type Communication). For example, LTE-M technology can be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and/or 7) LTE M, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the device (100, 200) of the present disclosure can include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create personal area networks (PAN) related to small/low-power digital communication based on various standards such as IEEE 802.15.4, and can be called by various names.

The method proposed in this disclosure is explained with a focus on examples applied to 3GPP LTE/LTE-A, 5G, and 6G systems, but can be applied to various wireless communication systems in addition to 3GPP LTE/LTE-A, 5G, and 6G systems.

Claims (17)

A step of acquiring, by a terminal, information related to a sequence overlaid on a synchronization signal; and A step of receiving the synchronization signal from the network by the terminal based on information related to the overlaid sequence, A method wherein the above overlaid sequence corresponds to one of the sequence candidates. In the first paragraph, A method wherein a set of the above sequence candidates is predefined. In the first paragraph, The different candidates within the above set are: Correspond to different sequence indices; correspond to different cyclic shift (CS) values; or A method corresponding to different combinations of sequence indices and CS values. In the third paragraph, A method wherein the above sequence index corresponds to at least one of a root index or a scrambling identifier. In the first paragraph, A method in which information related to the above overlaid sequence is signaled from the network to the terminal. In paragraph 5, A method wherein information related to the overlaid sequence comprises at least one of a sequence index or a CS value for the overlaid sequence. In the first paragraph, A method wherein information related to the overlaid sequence includes a physical cell identifier. In paragraph 7, A method wherein one of the sequence candidates is specified based on the physical cell identifier. In paragraph 7, Based on the above physical cell identifier: one sequence index; One CS value; or One combination of sequence index and CS value This is a specific method. In the first paragraph, A method wherein the above overlaid sequence is an orthogonal frequency division multiplexing (OFDM) sequence based on an on-off keying (OOK)-4 modulation technique. In the first paragraph, A method wherein the above synchronization signal is received by a low power wake-up receiver (LP-WUR) of the terminal. In the first paragraph, A method wherein the above synchronization signal is a low power-synchronization signal (LP-SS). one or more transceivers; and comprising one or more processors connected to said one or more transceivers, One or more of the above processors: Obtaining information related to a sequence overlaid on a synchronization signal; and Based on information related to the above overlaid sequence, the synchronization signal is set to be received from the network via the one or more transceivers, The above overlaid sequence corresponds to one of the sequence candidates, the terminal. A step of providing information related to a sequence overlaid on a synchronization signal to a terminal by a base station; and A step of transmitting the synchronization signal based on information related to the overlaid sequence to the terminal by the base station, A method wherein the above overlaid sequence corresponds to one of the sequence candidates. one or more transmitters and receivers; and comprising one or more processors connected to said one or more transceivers, One or more of the above processors: Providing information related to a sequence overlaid on a synchronization signal to a terminal through one or more of the transceivers; and The synchronization signal based on information related to the overlaid sequence is set to be transmitted to the terminal through the one or more transceivers, The above overlaid sequence corresponds to one of the sequence candidates, the base station. one or more processors; and A processing device comprising one or more computer memories operatively connected to said one or more processors and storing instructions for performing a method according to any one of claims 1 to 12 based on execution by said one or more processors. One or more non-transitory computer-readable media storing one or more instructions that are executed by one or more processors to control the performance of a method according to any one of claims 1 to 12.