Network node, user device, and communication method

Abstract

A network node according to one aspect is a network node that manages cells in a mobile communication system. The network node has: a control unit that sets, as different synchronization signal blocks, each of a plurality of synchronization signal blocks that can be simultaneously transmitted at different frequencies within the band of a cell; and a transmission unit that transmits setting information indicating the setting.

Description

Network node, user equipment, and communication method

[0001] The present invention relates to a network node, a user equipment, and a communication method.

[0002] The Third Generation Partnership Project (3GPP) (registered trademark; hereinafter the same), a standardization project for mobile communication systems, is discussing UAVs (Uncrewed Aerial Vehicles) (for example, Non-Patent Document 1). UAVs are also called drones. UAVs are aircraft without a human pilot on board and have the ability to fly autonomously. UAVs can also be controlled by a UAV controller. The combination of a UAV and a UAV controller is called a UAS (Uncrewed Aerial System). Through these specifications, 3GPP is able to appropriately support communications for UAVs flying in the sky.

[0003] Meanwhile, a network node (e.g., a base station) transmits a synchronization signal block (SSB: Synchronization Signal / Physical Broadcast Channel Block) using beamforming. Beamforming is a technology for transmitting or receiving radio waves in a specific direction. In particular, 5G (5th Generation), a technical specification of 3GPP, can use higher frequency bands than 4G (4th Generation), so the radio wave transmission direction is narrowed and propagation loss is compensated for by beam gain. In addition, a user equipment uses the SSB for cell search. Cell search is a procedure in which a user equipment obtains time and frequency synchronization with a cell and detects the cell ID (PCI: Physical Cell ID) of the cell. The user equipment performs cell search based on the primary synchronization signal, secondary synchronization signal, and PBCH demodulation reference signal (DMRS) in the SSB.

[0004] In order to transmit SSBs throughout the entire coverage area of ​​a cell, the network node performs beam sweeping, which switches the transmission beam direction (also referred to as a "beamforming pattern") of the SSBs at predetermined time intervals. By beam sweeping, the network node transmits each SSB within an SS burst in a time-division manner, each in a different transmission beam direction. This allows the SSBs within the SS burst to be distributed throughout the entire coverage area of ​​the cell. Note that an SS burst is specified to be set within a predetermined time length (specifically, the time of a half frame).

[0005] 3GPP TS 22.125 V18.0.0 (2023-9)3GPP TS 38.300 V17.6.0 (2023-9)

[0006] The network node assumes that the coverage area of ​​a cell is on the ground, so that one or more network nodes cover a certain area of ​​the ground, thereby optimizing the ground area with respect to the coverage area.

[0007] However, network nodes do not necessarily assume the sky as their coverage area, and the sky area is not necessarily optimized as a cell coverage area.

[0008] Therefore, UAVs in the sky may not be able to efficiently perform cell searches using SSBs transmitted from network nodes, and user equipment on the ground may not be able to efficiently perform cell searches either.

[0009] The present disclosure provides a network node, a user equipment, and a communication method that enable a user equipment to efficiently perform cell search, and also provides a network node, a user equipment, and a communication method that aim to reduce power consumption in the user equipment.

[0010] A network node according to a first aspect is a network node that manages a cell in a mobile communication system, and includes a control unit that sets each of a plurality of synchronization signal blocks that can be simultaneously transmitted at different frequencies within a band of the cell as a different synchronization signal block according to a beam type, and a transmission unit that transmits setting information representing the setting.

[0011] A user equipment according to a second aspect is a user equipment that performs wireless communication with a network node that manages a cell in a mobile communication system, and includes a receiving unit that receives, from the network node, configuration information for configuring each of a plurality of synchronization signal blocks that can be simultaneously transmitted at different frequencies within a band of the cell as a different synchronization signal block according to a beam type.

[0012] A communication method according to a third aspect is a communication method used in a network node that manages a cell in a mobile communication system, the communication method comprising the steps of: setting a plurality of synchronization signal blocks that can be simultaneously transmitted at different frequencies within a band of the cell as different synchronization signal blocks according to a beam type; and transmitting setting information representing the setting.

[0013] A fourth aspect of the present invention provides a communication method for a user equipment (UE) that performs wireless communication with a network node that manages a cell in a mobile communication system, the communication method comprising the steps of: receiving, from the network node, configuration information for configuring each of a plurality of synchronization signal blocks that can be simultaneously transmitted at different frequencies within a band of the cell as a different synchronization signal block according to a beam type;

[0014] FIG. 1 is a diagram illustrating an example of the configuration of a mobile communication system according to the first embodiment. FIG. 2 is a diagram illustrating an example of the configuration of a protocol stack related to the user plane according to the first embodiment. FIG. 3 is a diagram illustrating an example of the configuration of a protocol stack related to the control plane according to the first embodiment. FIG. 4 is a diagram illustrating an example of the configuration of a base station (network node) according to the first embodiment. FIG. 5 is a diagram illustrating an example of the configuration of a UE (user equipment) according to the first embodiment. FIG. 6 is a diagram illustrating an overview of SSB, beam sweeping, and cell search according to the first embodiment. FIG. 7 is a diagram illustrating an overview of SSB, beam sweeping, and cell search according to the first embodiment. FIG. 8 is a diagram illustrating OffsetToPointA and Kssb (ssb-SubcarrierOffset) according to the first embodiment. FIGS. 9(A) to 9(E) are diagrams illustrating an example of SSB transmission operation according to the first embodiment. FIGS. 10(A) to 10(E) are diagrams illustrating an example of SSB transmission operation according to the first embodiment. FIGS. 11(A) to 11(E) are diagrams illustrating an example of SSB transmission operation according to the first embodiment. FIGS. 12(A) to 12(E) are diagrams illustrating an example of SSB transmission operation according to the first embodiment. FIGS. 13(A) to 13(E) are diagrams illustrating an example of SSB transmission operation according to the first embodiment. FIG. 14(A) is a diagram illustrating an example of operation according to the first embodiment. FIG. 15 is a diagram illustrating an example of a frequency multiplexed SSB setting method according to the first embodiment. FIGS. 16(A) to 16(E) are diagrams illustrating an example of SSB transmission operation according to the second embodiment. FIG. 17 is a diagram illustrating an example of operation according to the second embodiment. FIG. 18 is a diagram for explaining a scenario according to the third embodiment. FIGS. 19(A) to 19(E) are diagrams illustrating an example of SSB transmission operation according to the third embodiment. FIG. 20 is a diagram illustrating an example of operation according to the third embodiment. FIGS. 21(A) to 21(E) are diagrams illustrating an example of SSB transmission operation according to the fourth embodiment. 22A to 22E are diagrams illustrating an example of an SSB transmission operation according to the fourth embodiment.

[0015] A mobile communication system according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0016] [First embodiment]

[0017] (1) Configuration Example of a Mobile Communication System Fig. 1 is a diagram showing a configuration example of a mobile communication system according to this embodiment. The mobile communication system according to this embodiment is a system conforming to the 3GPP standard. For example, the mobile communication system according to this embodiment may be a fifth-generation (5G) system or a sixth-generation (6G) system.

[0018] The mobile communication system includes a network (NW) 10 and a user equipment (UE) 100. The UE 100 is a mobile communication device that performs wireless communication with the NW 10. The UE 100 may be any device used by a user, and may be, for example, a mobile phone terminal (including a smartphone), a tablet terminal, a notebook PC (Personal Computer), a communication module (including a communication card or chipset), a sensor or a device provided in a sensor, a vehicle or a device provided in a vehicle (Vehicle UE), or an aircraft or a device provided in an aircraft (Aerial UE).

[0019] The NW 10 includes a radio access network (RAN) 20 and a core network (CN) 30. When the mobile communication system is a 5th generation system (5GS), the RAN 20 is referred to as a Next Generation Radio Access Network (NG-RAN), and the CN 30 is referred to as a 5G Core Network (5GC).

[0020] The RAN 20 includes a plurality of base stations 200 (base stations 200a to 200c in the illustrated example). The base stations 200 are connected to each other via an inter-base station interface. The base station 200 is an example of a network node. The base station 200 may be configured (i.e., functionally divided) with a CU (Central Unit) and a DU (Distributed Unit), and the two units may be connected via a fronthaul interface. When the mobile communication system is 5GS, the base station 200 is referred to as a gNB, the inter-base station interface is referred to as an Xn interface, and the fronthaul interface is referred to as an F1 interface.

[0021] Each base station 200 manages one or more cells. The base station 200 performs wireless communication with the UE 100 that has established a connection with the base station 200's cell. Each base station 200 has a radio resource management (RRM) function, a user data (also simply referred to as "data") routing function, a measurement control function for mobility control and scheduling, and the like. Note that the term "cell" is used to indicate the smallest unit of a wireless communication area. The term "cell" is also used to indicate a function or resource for performing wireless communication with the UE 100. One cell belongs to one carrier frequency. One downlink component carrier and one uplink component carrier may be associated with one cell. The bandwidth corresponding to one cell (system bandwidth) may be divided into multiple bandwidth parts (BWP: Bandwidth Parts).

[0022] The CN 30 includes a CN device 300. The CN device 300 may include a C-plane device corresponding to the control plane (C-plane) and a U-plane device corresponding to the user plane (U-plane). The C-plane device performs various mobility controls and paging for the UE 100. The C-plane device communicates with the UE 100 using NAS (Non-Access Stratum) signaling. The U-plane device controls data transfer. When the mobile communication system is 5GS, the C-plane device is referred to as an AMF (Access and Mobility Management Function), the U-plane device is referred to as a UPF (User Plane Function), and the interface between the base station 200 and the CN device 300 is referred to as an NG interface.

[0023] FIG. 2 is a diagram showing an example of the configuration of a protocol stack of a U-plane radio interface that handles data.

[0024] The U-plane radio interface protocol includes, for example, a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a service data adaptation protocol (SDAP) layer.

[0025] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the base station 200 via a physical channel. The PHY layer of the UE 100 receives downlink control information (DCI) transmitted from the base station 200 on a physical downlink control channel (PDCCH). Specifically, the UE 100 performs blind decoding of the PDCCH using a radio network temporary identifier (RNTI) and acquires successfully decoded DCI as DCI addressed to the UE. The DCI transmitted from the base station 200 has CRC parity bits scrambled by the RNTI added thereto.

[0026] The MAC layer performs data priority control and retransmission processing using Hybrid ARQ (HARQ). Data and control information are transmitted between the MAC layer of UE 100 and the MAC layer of base station 200 via a transport channel. The MAC layer of base station 200 includes a scheduler. The scheduler determines the uplink and downlink transport format (transport block size, modulation and coding scheme (MCS)) and the resources to be allocated to UE 100.

[0027] The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and the PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the base station 200 via logical channels.

[0028] The PDCP layer performs header compression / decompression, encryption / decryption, and the like.

[0029] The SDAP layer maps IP flows, which are units for QoS control by the CN 30, to radio bearers, which are units for QoS control by an AS (Access Stratum). Note that if the CN 30 controls QoS in the same units as the RAN 20 (i.e., if QoS control is performed in units of radio bearers rather than in units of IP flows and one-to-one mapping with radio bearers is possible), the SDAP layer may not be necessary.

[0030] FIG. 3 is a diagram showing an example of the configuration of a protocol stack of a C-plane radio interface that handles signaling (control signals).

[0031] The protocol stack of the C-plane radio interface includes, for example, an RRC (Radio Resource Control) layer and an NAS (Non-Access Stratum) layer instead of the SDAP layer shown in FIG.

[0032] RRC signaling for various settings is transmitted between the RRC layer of UE100 and the RRC layer of base station 200. The RRC layer controls logical channels, transport channels, and physical channels in accordance with the establishment, re-establishment, and release of radio bearers. When there is a connection (RRC connection) between the RRC of UE100 and the RRC of base station 200, UE100 is in an RRC connected state. When there is no connection (RRC connection) between the RRC of UE100 and the RRC of base station 200, UE100 is in an RRC idle state. When the connection between the RRC of UE100 and the RRC of base station 200 is suspended, UE100 is in an RRC inactive state.

[0033] The NAS layer (also simply referred to as "NAS") located above the RRC layer performs session management, mobility management, etc. NAS signaling is transmitted between the NAS layer of the UE 100 and the NAS layer of the CN device 300. Note that the UE 100 also has an application layer in addition to the radio interface protocol. The layer below the NAS layer is referred to as the AS layer (also simply referred to as "AS").

[0034] (2) Configuration Example of Base Station Fig. 4 is a diagram showing a configuration example of a base station 200 (network node) according to this embodiment. The base station 200 according to this embodiment may be configured to perform wireless communication in the sub-terahertz band.

[0035] The base station 200 includes a transmitting unit 210, a receiving unit 220, a control unit 230, and a NW communication unit 240. The transmitting unit 210 and the receiving unit 220 configure a wireless communication unit 250 that performs wireless communication with the UE 100.

[0036] The transmitting unit 210 performs various transmissions under the control of the control unit 230. The transmitting unit 210 includes an antenna and a transmitter. The transmitter converts a baseband signal (transmission signal) output by the control unit 230 into a radio signal and transmits it from the antenna. The receiving unit 220 performs various receptions under the control of the control unit 230. The receiving unit 220 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (reception signal) and outputs it to the control unit 230.

[0037] The control unit 230 performs various controls and processes in the base station 200. The operations of the base station 200 described below may be operations under the control of the control unit 230. The control unit 230 includes at least one processor and at least one memory. The memory stores programs executed by the processor and information used in the processing by the processor. The processor may include a baseband processor and a CPU. The baseband processor performs modulation / demodulation and encoding / decoding of baseband signals. The CPU executes programs stored in the memory to perform various processes.

[0038] The NW communication unit 240 is connected to adjacent base stations via an inter-base station interface, and is also connected to the CN device 300 via a base station-CN interface.

[0039] The transmitter 210 of the base station 200 configured in this manner transmits SSBs using beam sweeping, which switches the direction of the transmission beam at predetermined time intervals, and also transmits SSBs using beam forming for each transmission beam. Details of SSBs and beam forming will be described later.

[0040] (3) Example of Configuration of User Equipment Fig. 5 is a diagram showing an example of the configuration of the UE 100 (user equipment) according to this embodiment. The UE 100 according to this embodiment may be configured to perform wireless communication in the sub-terahertz band.

[0041] The UE 100 includes a receiving unit 110, a transmitting unit 120, and a control unit 130. The receiving unit 110 and the transmitting unit 120 configure a wireless communication unit 140 that performs wireless communication with the base station 200.

[0042] The receiving unit 110 performs various receptions under the control of the control unit 130. The receiving unit 110 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs it to the control unit 130. The transmitting unit 120 performs various transmissions under the control of the control unit 130. The transmitting unit 120 includes an antenna and a transmitter. The transmitter converts a baseband signal (transmitted signal) output by the control unit 130 into a radio signal and transmits it from the antenna.

[0043] The control unit 130 performs various controls and processes in the UE 100. The operations of the UE 100 described below may be operations controlled by the control unit 230. The control unit 130 includes at least one processor and at least one memory. The memory stores programs executed by the processor and information used in the processing by the processor. The processor may include a baseband processor and a CPU (Central Processing Unit). The baseband processor performs modulation / demodulation and encoding / decoding of baseband signals. The CPU executes programs stored in the memory to perform various processes.

[0044] The UE 100 configured in this manner performs wireless communication with a base station 200 that manages a cell in a mobile communication system. The receiver 110 receives an SSB that is transmitted from the base station 200 by beamforming and to which beam sweeping, which switches the transmission beam direction at predetermined time intervals, is applied. The controller 130 performs a cell search based on the SSB received by the receiver 110. Details of the cell search will be described later.

[0045] (4) UAV Here, the UAV (unmanned aerial vehicle) according to the first embodiment will be described.

[0046] A UAV generally refers to an unmanned aerial vehicle (UAV), such as a drone. However, in the first embodiment, a UE located at an altitude equal to or greater than a predetermined threshold is referred to as a UAV. A UAV may be a UE capable of wireless communication with a base station 200 while flying unmanned in the sky, like an unmanned aerial vehicle. Alternatively, a UAV may be provided on an unmanned aerial vehicle. Alternatively, a UAV may be provided on a manned aerial vehicle. In this case, for example, when an aircraft is flying at an altitude equal to or greater than a predetermined threshold, a UE owned by a user on the aircraft may also be a UAV. A UAV may be a UAV UE. Alternatively, a UAV may be an aerial UE (aerial UE). A UAV may be used to distinguish it from a UE used on the ground. However, when there is no particular distinction between the UE and the UAV, a UAV may be included in the UE as an example of a UE. In this case, a UAV and a UE may be collectively referred to as a UE. The configuration example of UE 100 shown in FIG. 5 may represent a configuration example of a UAV.

[0047] 3GPP defines C2 (command and control) communication as a function supporting UAVs. C2 communication is bidirectional communication required to control the operation of a UAV. For example, a UAV controller controls a UAV via C2 communication.

[0048] In 3GPP, the following C2 communications are considered to provide UAS services:

[0049] First, there is direct C2 communication, in which a direct C2 communication link is established between the UAV and the UAV controller, and radio resources scheduled and configured by the 5G network are used in direct C2 communication.

[0050] Second, there is network-assisted C2 communication, in which the UAV and the UAV controller establish a unicast C2 communication link and communicate over a 5G network.

[0051] Third, there is UTM-Navigated C2 Communication. UTM (Uncrewed Aerial System Traffic Management) is a collection of functions and services that manage the scope of automated flight operations. The UTM may be an entity or node that supports the operation of a UAS. In UTM-Navigated C2 Communication, the UTM provides a pre-scheduled flight plan to the UAV for its autonomous flight. The UTM maintains C2 communication with the UAV to periodically monitor the flight status of the UAV, update the flight route, and navigate the UAV.

[0052] In addition, 3GPP defines four control modes for operating UAVs in relation to C2 communication.

[0053] First, there is a steer-to-waypoints mode. Waypoints are included in control messages sent from the UAV controller or UTM. Steer-to-waypoints mode is used in both direct and network-assisted C2 communications.

[0054] Second, there is a direct stick steering mode. In direct stick steering mode, control messages containing directional instructions are sent from the UAV controller to the UAV. Optionally, video traffic may be provided from the UAV to the UAV controller. Direct stick steering mode is used in both direct and network-assisted C2 communications.

[0055] The third mode is Automatic Flight by UTM. In Automatic Flight by UTM mode, the UTM transmits a control message containing a flight plan to the UAV. The flight plan may be represented by a 4D polygon. The UAV then flies autonomously while periodically reporting its position. Automatic Flight by UTM mode is used in UTM Navigate C2 communication.

[0056] Fourth, there is an Approaching Autonomous Navigation Infrastructure mode. In this mode, the UTM sends control messages containing directional instructions (waypoints, altitude, speed, etc.) to the UAV. When the UAV lands or takes off, the UTM closely coordinates with the autonomous navigation infrastructure (e.g., a package distribution center). This mode is used in UTM-navigate C2 communications.

[0057] As described above, hereinafter, there is a case where the UAV and the UE 100 are not distinguished from each other and are referred to as the UE 100. On the other hand, when there is a case where the UAV and the UE 100 are distinguished from each other, they are referred to as the UAV UE and the ground UE, respectively.

[0058] (5) SSB, Beam Sweeping, and Cell Search Next, SSB, beam sweeping, and cell search will be described.

[0059] 6 and 7 are diagrams for explaining SSB, beam sweeping, and cell search according to the first embodiment.

[0060] As shown in FIG. 6 , in the frame structure used for 5G / NR wireless communication, one frame (radio frame) is 10 ms in the time axis direction. A frame is composed of 10 subframes, each of which is 1 ms. Each subframe is composed of a number of slots according to the waveform configuration (also referred to as "numerology"), such as the subcarrier spacing. Specifically, the length of the slot in the time axis direction becomes shorter as the subcarrier spacing increases. The number of symbols in one slot is 14 in the case of a normal CP (Cyclic Prefix). Meanwhile, one resource block (RB) is composed of 12 subcarriers in the frequency axis direction. Furthermore, one symbol and one subcarrier constitute one resource element (RE).

[0061] The transmitter 210 of the base station 200 that manages the cell transmits SSBs (SS / PBCH blocks) used for cell search by the UE 100. Each SSB consists of four symbols in the time axis direction and 240 consecutive subcarriers (i.e., 20 RBs) in the frequency axis direction. These subcarriers are numbered in ascending order from 0 to 239 within the SSB, from the lowest frequency side to the highest frequency side. The lowest frequency subcarrier within an SSB is also referred to as subcarrier 0. Note that each of the PSS and SSS consists of one symbol and 127 subcarriers. The PBCH consists of three symbols and 240 subcarriers.

[0062] Each SSB includes a synchronization signal (SS) and a physical broadcast channel (PBCH). The SS includes a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). The PSS and SSS are used for synchronization at least in the time axis direction. The combination of the PSS and SSS signal sequences indicates the cell ID (PCI: Physical Cell ID) of the transmitting cell. The PBCH includes a master information block (MIB) and a demodulation reference signal (DMRS). The MIB includes parameters for decoding the system information block type 1 (SIB1). The DMRS is a reference signal for decoding the PBCH. Note that SIB1 is also referred to as the remaining minimum system information (RMSI). The SSB associated with SIB1 (RMSI) is referred to as a cell-defined SSB (CD-SSB). In the following, SSB refers to a CD-SSB.

[0063] The SSBs are arranged continuously in the time direction at specific frequencies within the cell band. Specifically, in the current 3GPP technical specifications, the SSBs are arranged at a unique frequency predetermined by the base station 200, and the SSBs are repeatedly transmitted in the time direction. The positions of the SSBs on the frequency axis can be notified from the base station 200 to the UE 100 by RRC signaling.

[0064] The transmitter 210 of the base station 200 periodically transmits SS bursts (also referred to as "SS burst sets" or "synchronization signal bursts") consisting of multiple SSBs arranged in the time direction. The transmission period of the SS bursts can be selected from 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, and 160 ms, with 20 ms being the most common. The maximum number of SSBs in one SS burst, i.e., the maximum number of consecutive SSBs, is 8 for FR1, which corresponds to the Sub6 band, and 64 for FR2, which corresponds to the millimeter wave band. In the example of FIG. 6, the transmission period of the SS bursts is 20 ms, and the number of SSBs in an SS burst is 8. Note that SS bursts are specified to be set within the time of a half frame (5 ms). The time positions at which SSBs can be placed within a half frame are determined according to the subcarrier spacing. On the other hand, the transmission period of the SS burst (i.e., the periodicity of the half frame in which the SSB is transmitted) is set by the NW 10 (base station 200).

[0065] Although the example of Figure 6 shows a case where all SSBs in an SS burst are transmitted, the base station 200 does not necessarily need to transmit all SSBs in an SS burst. The base station 200 can selectively transmit only some of the SSBs in an SS burst according to the requirements of the network 10. Furthermore, the base station 200 can notify the UE 100 by RRC signaling which SSBs are transmitted and which are not transmitted in an SS burst. Specifically, this transmission pattern is notified to the UE 100 as bitmap information by an RRC information element (IE) such as ssb-PositionInBurst.

[0066] The control unit 230 of the base station 200 assigns an SSB index (SSB Index), which is an identifier of the SSB, to each SSB in an SS burst. The SSB Index may be a unique number that starts from 0 and increments by 1, as shown in FIG. 6 , or may be a unique number that starts from "1" and increments by 1. This number is reset to the starting number in the next SS burst. If the SSB Index starts from 0, the SSB Index is reset to 0 in the next SS burst. If the SSB Index starts from 1, the SSB Index is reset to 1 in the next SS burst. The base station 200 notifies the UE 100 of the SSB Index via the PBCH in the SSB. The UE 100 that has received the SSB can identify the SSB index of the SSB based on the PBCH in the received SSB.

[0067] As shown in FIG. 7 , in order to transmit SSBs throughout the entire coverage area of ​​the cell, the transmitter 210 of the base station 200 performs beam sweeping, which switches the transmission beam direction of the SSBs (also referred to as a "beamforming pattern (BF pattern)") at predetermined time intervals within the period of each SS burst (SS burst period). That is, the base station 200 uses beam sweeping to time-division transmit each SSB within an SS burst in a different transmission beam direction. Therefore, during a half frame, different SSBs are transmitted in different spatial directions (i.e., different transmission beam directions) across the cell coverage area. This allows the SSBs to be transmitted throughout the entire coverage area of ​​the cell (cell coverage) within the SS burst, even when beamforming is used to transmit the SSBs.

[0068] Meanwhile, the control unit 130 of the UE 100 performs a cell search based on the SSB (specifically, the PSS, SSS, and DMRS in the SSB). The cell search is a procedure in which the UE 100 obtains time synchronization and frequency synchronization with a cell and detects the cell ID of the cell. The receiving unit 110 of the UE 100 performs an SSB scan (cell search) on a synchronization raster, which is a position on the frequency axis where the SSB can be located. The receiving unit 110 (or the control unit 130) of the UE 100 measures the reception quality of each received SSB and identifies an SSB index of an SSB whose reception quality satisfies a predetermined condition, thereby identifying an appropriate beam. Here, the reception quality may be RSRP (Reference Signal Received Power) in the SSB. The predetermined condition may be a condition that the reception quality exceeds a threshold. The predetermined condition may be a condition that the reception quality is the highest among SSBs received within a predetermined period (e.g., an SS burst period). In the example of FIG. 7, since the reception quality of SSB#1 is the highest, UE 100 can identify SSB#1 as the SSB whose reception quality satisfies a predetermined condition.

[0069] The control unit 130 of the UE 100 performs random access (RA) for initial access to the NW 10 (base station 200). Specifically, the transmission unit 120 of the UE 100 transmits an RA preamble to the base station 200 to perform RA. RA occasions, which are timings at which RA preambles can be transmitted, are prepared as many times as the number of transmission beams of the base station 200 (i.e., the number of SSBs in an SS burst). The UE 100 transmits the RA preamble to the base station 200 in the RA occasion corresponding to an SSB (SSB Index) whose reception quality satisfies a predetermined condition. The control unit 230 of the base station 200 that receives the RA preamble can determine a transmission beam preferred for the UE 100 (i.e., the direction in which the UE 100 is located) based on the correspondence between the beam (SSB Index) and the RA occasion.

[0070] The RA occasion is notified to UE 100 in system information provided by base station 200. Specifically, transmission unit 210 of base station 200 notifies UE 100 of the time and frequency resources of the RA occasion. There is a one-to-one relationship between SSB and RA occasion. When base station 200 directs a transmission beam in a certain direction and receives an RA occasion corresponding to the SSB, it receives using a reception beam directed in the same direction as the transmission beam.

[0071] In the mobile communication system 1, beam sweeping and cell search are performed as described above.

[0072] The transmitter 210 of the base station 200 transmits configuration information indicating SSB parameters. The configuration information may be transmitted to the receiver 110 of the UE 100 using the PBCH (MIB), the SIB, or an RRC message (for example, an RRC Reconfiguration message). The configuration information may include at least one piece of information (SSB parameters) from the following (A1) to (A3).

[0073] (A1) OffsetToPointA Figure 8 is a diagram for explaining OffsetToPointA and Kssb (ssb-SubcarrierOffset) according to the first embodiment. As shown in Figure 8, OffsetToPointA is information indicating, in resource block units, the frequency offset between the subcarrier (subcarrier 0) on the lowest frequency side of the corresponding SSB and a reference point (referred to as "Point A") of the resource block grid. Point A indicates a position on the reference frequency axis. The transmitter 210 of the base station 200 may transmit (set) the OffsetToPointA of the SSB to be transmitted in its own cell in the SIB1 to be broadcast in its own cell.

[0074] (A2) Kssb (ssb-SubcarrierOffset) Kssb (ssb-SubcarrierOffset) is, as shown in FIG. 8, information indicating the frequency offset between the subcarrier (subcarrier 0) of the corresponding SSB at the lowest frequency and the boundary of the resource block to which the subcarrier (subcarrier 0) belongs, in subcarrier units. Therefore, UE 100 can obtain the reference point (Point A) of the resource block grid by subtracting the sum of Kssb (ssb-SubcarrierOffset) and OffsetToPointA from subcarrier 0. The transmitter 210 of base station 200 may transmit (set) the Kssb (ssb-SubcarrierOffset) of the SSB to be transmitted within the cell in the MIB broadcast in its own cell.

[0075] (A3) absoluteFrequencySSB absoluteFrequencySSB is information indicating the frequency of the corresponding SSB (ARFCN: Absolute Radio-Frequency Channel Number). The frequency indicated by absoluteFrequencySSB may be the position of resource element RE=#0 of resource block RB#10 of the SSB. For example, when configuring a secondary cell (SCell) for UE 100, transmission unit 210 of base station 200 may include absoluteFrequencySSB for the secondary cell in an RRC Reconfiguration message and transmit (configure) it to UE 100.

[0076] (6) Communication Method According to First Embodiment As described above, in the base station 200 (network node), the coverage area facing the sky is not necessarily optimized.

[0077] To optimize the coverage area, it is possible to uptilt the directional antenna used in the transmitter 210 of the base station 200, for example. However, changing the setting of the directional antenna is not practical in terms of cost and other factors.

[0078] On the other hand, in 5G / NR, a panel antenna (or array antenna) with multiple antenna elements mounted on a flat panel can be used to perform beamforming in three dimensions by controlling the phase (or angle) of the signal transmitted from each antenna element. Therefore, a single panel antenna can perform beamforming toward both the ground area and the sky area. Furthermore, a single panel antenna can also perform SSB transmission to the sky area and SSB transmission to the ground area in a time-division manner by beam sweeping.

[0079] However, the current SSB specifications do not distinguish between SSB for the sky area and SSB for the ground area. Assume that base station 200 transmits SSB to the sky area and SSB to the ground area in a time-division manner using beam sweeping. In this case, a UAV flying in the sky area may measure both SSB for the sky area and SSB for the ground area during a cell search. Furthermore, a ground UE located in the ground area may also measure both SSB for the sky area and SSB for the ground area during a cell search.

[0080] In this way, the UE 100 (UAV UE and terrestrial UE) may measure SSBs that are not related to the geographical area to which it belongs, and cell search may not necessarily be performed efficiently.

[0081] Therefore, the first embodiment aims to improve the efficiency of the cell search in the UE 100. And, the first embodiment also aims to reduce the power consumption in the UE 100 by improving the efficiency of the cell search.

[0082] Here, as a comparative example, an SSB transmission pattern in which SSB for the sky and SSB for the ground are transmitted in a time-division manner will be described.

[0083] 9A to 9E show examples of SSB transmission operations according to the first embodiment. Of these, FIGS. 9A to 9C show examples of bitmap information according to the current 3GPP specifications. Also, FIG. 9D shows an example of an SSB transmission pattern. Finally, FIG. 9E shows an example of measurement operations during cell search by UE 100.

[0084] As described above, the base station 200 does not necessarily need to transmit all SSBs in an SS burst, but can selectively transmit only some of the SSBs. Whether an SSB is transmitted at an SSB transmittable timing is indicated by bitmap information.

[0085] (B1) inOneGroup Figure 9(B) shows an example of inOneGroup. inOneGroup defines a predetermined period (a period corresponding to eight consecutive SSB indices) within an SS burst (one cycle period) as one group, and indicates whether or not an SSB is transmitted for each SSB index (or SSB transmittable timing) within the group. In the current 3GPP specifications, inOneGroup is represented as 8-bit bitmap information (e.g., first bitmap information). The leftmost bit corresponds to SSB index #0, and the second bit corresponds to SSB index #1. Bit "0" indicates that no SSB is transmitted at that SSB index, and bit "1" indicates that an SSB is transmitted at that SSB index. When the total number of SSBs per half frame is "4," the leftmost 4 bits of the 8-bit inOneGroup are valid, and the rightmost 4 bits are ignored. Furthermore, when the total number of SSBs per half frame is "8," all 8 bits of inOneGroup are valid. Furthermore, when the total number of SSBs per half frame is "64," all 8 bits of inOneGroup are valid. However, in this case, if eight consecutive SSB indexes are considered as one group, and an SSB is transmitted at one SSB index within that group and an SSB is transmitted at one SSB index within another group, the bitmap information of inOneGroup will be the same between the two groups. For example, as shown in FIG. 9B , if an SSB is transmitted in the first eight consecutive SSB indexes (i.e., one group) and an SSB is transmitted in the next eight consecutive SSB indexes, the bitmap information of inOneGroup for the first eight SSB indexes and the bitmap information of inOneGroup for the next eight SSB indexes will be the same.

[0086] (B2) groupPresence Figure 9(A) shows an example of groupPresence. As shown in Figure 9(A), the leftmost bit of groupPresence corresponds to SSB index #0 to SSB index #7, and the next bit corresponds to SSB index #8 to SSB index #15. groupPresence is also represented as bitmap information (e.g., second bitmap information). In groupPresence, a bit "1" indicates that an SSB is transmitted at at least one SSB index among eight consecutive SSB indexes (i.e., one group), and a bit "0" indicates that no SSB is transmitted in one group. In other words, groupPresence is bitmap information that indicates whether or not an SSB is transmitted for each predetermined period (a period corresponding to eight consecutive SSB indexes) within an SS burst. In the current 3GPP specifications, groupPresence is also 8 bits long and exists when the number of SSBs per half frame is "64".

[0087] (B3) ssb-PositionInBurst Figure 9(C) shows an example of ssb-PositionInBurst. ssb-PositionInBurst indicates the position of an SSB in the time domain within an SS burst. Specifically, ssb-PositionInBurst indicates whether or not an SSB is to be transmitted for each SSB index (or for each SSB transmittable timing) for all SSB indexes within the SS burst. ssb-PositionInBurst is also an example of bitmap information (for example, third bitmap information).

[0088] The ssb-PositionInBurst may include groupPresence and inOneGroup. Therefore, the transmitter 210 of the base station 200 can transmit inOneGroup and groupPresence by transmitting the ssb-PositionInBurst. The control unit 130 of the UE 100 can check whether or not an SSB is being transmitted for each SSB index by using a combination of inOneGroup and groupPresence. For example, the control unit 130 of the UE 100 can perform the following processing.

[0089] That is, when groupPresence is "1," the control unit 130 confirms that SSBs are transmitted within a group of eight consecutive SSB indexes, and by checking inOneGroup, checks whether SSBs are transmitted for each of the eight SSB indexes within the group. The control unit 130 then receives SSBs at the timing of each SSB index for which inOneGroup is "1" (i.e., the transmission timing of each SSB), and does not receive SSBs at the timing of each SSB index for which inOneGroup is "0" (i.e., the transmission timing of each SSB). On the other hand, when groupPresence is "0," the control unit 130 confirms that SSBs are not transmitted within that group, and does not receive SSBs. The control unit 130 can also cause the receiving unit 110 to perform an SSB reception operation when an SSB is transmitted, and not to perform an SSB reception operation when an SSB is not transmitted. Note that the meanings of "0" and "1" in the bitmap information may be reversed.

[0090] In the current 3GPP specifications, ssb-PositionInBurst has a 16-bit configuration, consisting of 8 bits for inOneGroup and 8 bits for groupPresence. Therefore, as described above, the bitmap information used in inOneGroup is the same for other groups in the same burst.

[0091] The ssb-PositionInBurst (or inOneGroup and groupPresence included in the ssb-PositionInBurst) is transmitted by the transmitter 210 of the base station 200 using SIB1, and can be received by the receiver 110 of the UE 100. Also, the SSB index is transmitted by the transmitter 210 of the base station 200 using the PBCH of the SSB, and can be received by the receiver 110 of the UE 100. Therefore, the control unit 130 of the UE 100 can use the SSB index and the ssb-PositionInBurst (or inOneGroup and groupPresence included in the ssb-PositionInBurst) to check whether or not an SSB has been transmitted for each SSB index, and can receive the SSB.

[0092] Note that the ssb-PositionInBurst can also be transmitted as an individual RRC message (for example, an RRCReconfiguration message). In this case, the ssb-PositionInBurst does not include inOneGroup and groupPresence. Instead, the ssb-PositionInBurst includes, for each SSB index within the SS burst, a bit indicating whether or not an SSB is transmitted, for each SSB index within the SS burst. In this case, the ssb-PositionInBurst can have a number of bits (such as 4 bits, 8 bits, or 64 bits) according to the number of SSBs (or the number of SSB indices) per half frame. For example, in the example of the ssb-PositionInBurst shown in FIG. 9(C), the presence or absence of SSB transmission is indicated over 64 bits.

[0093] In this way, whether or not to transmit an SSB within an SS burst (or one cycle period) of a predetermined frequency can be expressed as bitmap information using inOneGroup and groupPresence (or ssb-PositionInBurst). Then, UE 100 can use the bitmap information to check whether or not to transmit an SSB.

[0094] The above is an example of an SSB transmission pattern as a comparative example.

[0095] As mentioned above, the current 3GPP specifications do not distinguish between SSB for the air and SSB for the ground.

[0096] Therefore, as shown in Figure 9(E), whether the UE is a UAV or a terrestrial UE, both the airborne SSB and the terrestrial SSB are measured in the cell search, which is not necessarily efficient.

[0097] Therefore, in the first embodiment, the base station 200 transmits a plurality of bitmap information pieces that are different depending on the type of bitmap information, which are bitmap information indicating whether or not to transmit SSB within an SS burst period (one cycle period) at a predetermined frequency. Examples of bitmap information pieces according to the type include the following:

[0098] (7) Examples of Bitmap Information First, the type may be altitude. That is, the bitmap information may include multiple pieces of bitmap information corresponding to altitudes. Specifically, the bitmap information may include inOneGroup (bitmap information) for the sky and inOneGroup (bitmap information) for the ground.

[0099] 10(A) to 10(E) show examples of SSB transmission operations when different inOneGroups are used for the sky and the ground. In the example shown in FIG. 10(B), an inOneGroup for the sky ("inOneGroupAerial") and an inOneGroup for the ground ("inOneGroupTerrestrial") are set. If UE 100 can determine whether it is located in the sky or on the ground, it can apply either inOneGroup depending on its location. Then, for example, when UE 100 is located in the sky, it checks the inOneGroup for the sky. For example, the receiver 110 of UE 100 receives SSBs at the timing of the SSB index of "1" in the inOneGroup for the sky (i.e., the SSB transmission timing), but does not receive SSBs at the timing of the SSB index of "0." This allows the receiver 110 of UE 100 located in the sky to receive SSBs transmitted for the sky without receiving SSBs transmitted for terrestrial use (FIG. 10(E)). Also, for example, when UE 100 is located on the ground, it checks the inOneGroup for the ground. For example, the receiver 110 of UE 100 receives SSBs at the timing of the SSB index of "1" in the inOneGroup for the ground (i.e., the SSB transmission timing), but does not receive SSBs at the timing of the SSB index of "0." As a result, the receiver 110 of the UE 100 located on the ground can receive the SSB transmitted for terrestrial use without receiving the SSB transmitted for aerial use (FIG. 10(E)). Therefore, the UE 100 can shorten the cell search time and perform the cell search efficiently compared to the case where the UE 100 receives both the SSB for aerial use and the SSB for terrestrial use as shown in FIG. 9(B). Therefore, the UE 100 can reduce power consumption compared to the case of FIG. 9(B).

[0100] The transmitter 210 of the base station 200 transmits an altitude threshold to identify whether the location is in the sky or on the ground. The transmitter 210 of the base station 200 may transmit the altitude threshold by including it in SIB1. The receiver 110 of the UE 100 receives the altitude threshold. The control unit 130 of the UE 100 identifies either an inOneGroup for the sky or an inOneGroup for the ground based on the altitude threshold. Specifically, the control unit 130 measures its own altitude. The control unit 130 may measure the altitude of the UE 100 using an altitude sensor provided in the UE 100, or may measure the altitude using a distance sensor (such as radar or lidar) provided in the UE 100. The altitude may be expressed in terms of height above sea level, altitude above sea level, or height from the ground. The control unit 130 may then determine that the location is in the sky when the measured altitude is equal to or greater than the altitude threshold, and determine that the location is on the ground when the measured altitude is less than the altitude threshold. When the control unit 130 determines that the location is in the sky, it decides to apply inOneGroup for the sky, and when the control unit 130 determines that the location is on the ground, it decides to apply inOneGroup for the ground.

[0101] As shown in FIG. 10B, the transmitter 210 of the base station 200 may transmit a conventional inOneGroup ("inOneGroup"). For example, some UEs 100 may be unable to process both the inOneGroup for air and the inOneGroup for terrestrial use, even if they receive them. For such UEs 100 (hereinafter, sometimes referred to as "legacy UEs"), the base station 200 transmits the conventional inOneGroup as a legacy UE. This allows the legacy UE to check the inOneGroup and determine whether SSB is being transmitted. However, in this case, the legacy UE measures SSBs during cell search without distinguishing between SSBs for air and SSBs for terrestrial use (FIG. 10E).

[0102] Second, the type may include an absolute position in space. That is, the bitmap information includes multiple pieces of bitmap information corresponding to absolute positions in space. Specifically, the bitmap information may include an inOneGroup (bitmap information) corresponding to a first area in space and an inOneGroup (bitmap information) corresponding to a second area in space. For example, in FIG. 10B , the inOneGroup for the sky ("inOneGroupAerial") may be replaced with an inOneGroup for the first area (e.g., "inOneGroupFirstArea"), and the inOneGroup for the ground ("inOneGroupTerrestrial") may be replaced with an inOneGroup for the second area (e.g., "inOneGroupSecondArea"). In order for UE 100 to identify which inOneGroup it is, the transmitter 210 of base station 200 transmits a spatial threshold. The spatial threshold may be represented by latitude and longitude. Latitude and longitude are represented by two-dimensional coordinates in a terrestrial area. However, for example, it is also possible to identify a spatial region by extending the two-dimensional region represented by latitude and longitude vertically up to a predetermined altitude. Furthermore, the spatial threshold may include latitude and longitude, and may also include height information. The control unit 130 of UE 100 may measure the position (and height) using its own GNSS reception function, etc. By comparing the measured position with the altitude threshold, the control unit 130 can identify the inOneGroup corresponding to the first region and the inOneGroup corresponding to the second region. Then, the receiving unit 110 of the UE 100 can receive either the SSB for the first region or the SSB for the second region by using the bitmap information represented by any of the identified inOneGroups. In this case, the UE 100 can receive either the SSB according to the absolute position in space and perform a cell search, compared to when the UE 100 receives all of the SSB for the first region and the SSB for the second region. Therefore, it is possible to improve the efficiency of the cell search in the UE 100 and reduce power consumption.

[0103] (8) Other Examples of Bitmap Information Next, other examples of bitmap information will be described.

[0104] (8-1) Another Example of Bitmap Information 1 Figures 11(A) to 11(E) are diagrams showing another example of the SSB transmission operation according to the first embodiment. Compared to the example shown in Figures 10(A) to 10(E), Figures 11(A) to 11(E) show an example in which the conventional inOneGroup is not transmitted. In this case, as described above, the target UE 100 (e.g., a UE for Rel-19) capable of processing the inOneGroup for the sky and the inOneGroup for the ground can be used. Note that even when the type is absolute position, the conventional inOneGroup may not be transmitted, and an inOneGroup for each region may be set.

[0105] (8-2) Another Example of Bitmap Information 2 Figures 12(A) to 12(E) are diagrams showing another example of the SSB transmission operation according to the first embodiment. Figures 12(A) to 12(E) show an example in which two inOneGroups are set: an inOneGroup for the sky ("inOneGroupAerial") and a conventional inOneGroup ("inOneGroup"). In this case, it is possible to handle both legacy UEs that cannot process the inOneGroup for the sky and Rel-19 UEs 100 that can process the inOneGroup for the sky. In other words, the legacy UEs use the conventional inOneGroup. On the other hand, when the Rel-19 UE 100 determines that it is located in the sky, it uses the inOneGroup for the sky to receive SSB. Also, when the Rel-19 UE 100 determines that it is located on the ground, it uses the conventional inOneGroup to receive SSB. As a result, for example, a UAV UE flying in the sky can receive SSB for the sky without receiving SSB for the ground by checking the inOneGroup for the sky. Therefore, the UAV UE can perform cell search more efficiently than when receiving SSB for the ground, and can reduce power consumption.

[0106] In addition, when the type is absolute location, the inOneGroup for the first area and the conventional inOneGroup may be transmitted from the base station 200. When the UE 100 for Rel-19 determines that it is located in the first area, it uses the inOneGroup for the first area, and when it determines that it is located in any other area, it uses the conventional inOneGroup. A legacy UE may use the conventional inOneGroup.

[0107] (8-3) Other Example 3 of Bitmap Information Although the bitmap information has been described above as an example in which multiple inOneGroups are set according to the type of inOneGroup, the present invention is not limited to this. For example, multiple groupPresences may be set according to the type of groupPresence.

[0108] 13(A) to 13(E) show an example of SSB transmission operation when a groupPresence for the sky ("groupPresenceAerial") and a groupPresence for the ground ("groupPresenceTerrestrial") are set. That is, they show an example in which groupPresence is a different groupPresence (bitmap information) depending on the altitude (type), whether sky or ground. In this case, too, the transmitter 210 of the base station 200 transmits the altitude threshold. The receiver 110 of the UE 100 receives the altitude threshold. The control unit 130 of the UE 100 identifies either the groupPresence for the sky or the groupPresence for the ground based on the altitude threshold, and decides to apply the identified groupPresence.

[0109] UE 100 that has decided to apply groupPresence for the sky receives SSB using groupPresence for the sky. That is, receiver 110 of UE 100 checks inOneGroup in the group where groupPresence for the sky is "1," receives SSB at the timing of the SSB index where inOneGroup is "1" (i.e., SSB transmission timing), and does not receive SSB at the timing of the SSB index where inOneGroup is "0" (FIG. 13(E)). As a result, UE 100 located in the sky can receive SSB transmitted for the sky without receiving SSB transmitted for terrestrial use by checking groupPresence for the sky and inOneGroup in the group where groupPresence for the sky is "1."

[0110] On the other hand, UE 100 that has decided to apply groupPresence for terrestrial use also checks inOneGroup in the group for which groupPresence for terrestrial use is "1," receives SSBs at the timing of the SSB index for which inOneGroup is "1" (i.e., SSB transmission timing), and does not receive SSBs at the timing of the SSB index for which inOneGroup is "0" (FIG. 13(E)). In this way, UE 100 located on the ground can receive SSBs transmitted for terrestrial use without receiving SSBs transmitted for aerial use by checking groupPresence for terrestrial use and inOneGroup in the group for which groupPresence for terrestrial use is "1."

[0111] The receiving unit 110 may not perform a receiving operation for a group for which both the groupPresence for the sky and the groupPresence for the ground are "0".

[0112] Regarding groupPresence, in addition to groupPresence for the sky and groupPresence for the ground, a conventional groupPresence ("groupPresence") may be set. A legacy UE that cannot process groupPresence for the sky and groupPresence for the ground can check this conventional groupPresence to determine whether SSBs are transmitted within a group. However, in this case, the legacy UE cannot distinguish between SSBs for the sky and SSBs for the ground, so it receives all SSBs and performs a cell search.

[0113] Furthermore, with regard to groupPresence, two groupPresences may be set: a groupPresence for the sky and a conventional groupPresence ("groupPresence"). A UE 100 capable of processing a groupPresence for the sky (for example, a UE for Rel-19) uses the groupPresence for the sky when it determines that it is located in the sky based on an altitude threshold, and uses the conventional groupPresence when it determines that it is located on the ground. On the other hand, a legacy UE uses the conventional groupPresence.

[0114] The above description of groupPresence has been given with reference to an example in which the type is altitude, but it can also be applied to an example in which the type is an absolute position in space. In the above description, the sky-related information can be read as the first area-related information and the ground-related information can be read as the second area-related information.

[0115] (8-4) Other Example 4 of Bitmap Information In the above description, an example was described in which inOneGroup and groupPresence are set separately, with multiple inOneGroups and groupPresences that differ depending on the type, but the bitmap information is not limited to this. For example, multiple inOneGroups that differ depending on the type may be set for inOneGroup, and multiple groupPresences that differ depending on the type may also be set for groupPresence. In this case, for example, the transmitter 210 of the base station 200 may transmit an inOneGroup for the sky, an inOneGroup for the ground, a groupPresence for the sky, and a groupPresence for the ground. In this case, the transmitter 210 of the base station 200 may transmit the conventional inOneGroup and the conventional groupPresence for the legacy UE.

[0116] In this case, the type can also be distinguished by the absolute position in space. In the above description, the sky use can be read as the first area use, and the ground use can be read as the second area use, respectively.

[0117] 10(A) to 10(E) illustrate an example in which two sets of bitmap information, one for the sky and one for the ground, are provided for different altitudes. However, three or more sets of bitmap information may be provided for different altitudes. For example, three sets of bitmap information may be provided for different altitudes: inOneGroup for the ground (and / or groupPresence for the ground), inOneGroup for a medium altitude (and / or groupPresence for a medium altitude), and inOneGroup for a high altitude (and / or groupPresence for a high altitude).

[0118] The transmitting unit 210 of the base station 200 may set the bitmap information by transmitting the altitude-specific bitmap information and the altitude threshold in a list format such as {(bitmap information #1, altitude threshold #1), (bitmap information #2, altitude threshold #2), (bitmap information #3, altitude threshold #3), ...}. The bitmap information corresponds to inOneGroup and / or groupPresence. Each altitude threshold and the bitmap information may be associated, and the control unit 130 of the UE 100 may apply bitmap information #1 when the altitude is less than the altitude threshold #1, and apply bitmap information #2 when the altitude is equal to or greater than the altitude threshold #1 and less than the altitude threshold #2. The altitude threshold may be indicated as a range.

[0119] Furthermore, even when the type is an absolute position in space, three or more bitmap information may be set. For example, an inOneGroup for a first region (and / or a groupPresence for the first region), an inOneGroup for a second region (and / or a groupPresence for the second region), and an inOneGroup for a third region (and / or a groupPresence for high altitude) may be set. The transmitter 210 of the base station 200 may transmit the bitmap information and the spatial threshold for each region in a list format. The spatial threshold may also be expressed as a range.

[0120] (9) Operation Example According to First Embodiment Next, an operation example according to the first embodiment will be described.

[0121] Fig. 14 is a diagram illustrating an example of operation according to the first embodiment. Note that Fig. 14 illustrates an example of operation when the type is "altitude."

[0122] In step S10, the UE 100 may be in an RRC idle state or an RRC inactive state.

[0123] In step S11, the transmitting unit 210 of the base station 200 broadcasts altitude-specific bitmap information and altitude thresholds using SIB1.

[0124] The altitude-specific bitmap information may include inOneGroup (bitmap information) for the sky and inOneGroup (bitmap information) for the ground. Alternatively, the altitude-specific bitmap information may include groupPresence (bitmap information) for the sky and groupPresence (bitmap information) for the ground. Alternatively, the altitude-specific bitmap information may include inOneGroup for the sky, inOneGroup for the ground, groupPresence for the sky, and groupPresence for the ground.

[0125] Instead of the altitude, the location may be represented by an absolute position in space. In this case, the altitude-specific bitmap information becomes region-specific bitmap information. The region-specific bitmap information may include an inOneGroup (bitmap information) corresponding to the first region and an inOneGroup (bitmap information) corresponding to the second region. Alternatively, the region-specific bitmap information may include a groupPresence (bitmap information) corresponding to the first region and a groupPresence (bitmap information) corresponding to the second region. Alternatively, the region-specific bitmap information may include an inOneGroup corresponding to the first region, an inOneGroup corresponding to the second region, a groupPresence corresponding to the first region, and a groupPresence corresponding to the second region. When an absolute position in space is used instead of the altitude, a spatial threshold (e.g., latitude and longitude) for identifying the region may be transmitted instead of the altitude threshold.

[0126] The transmitting unit 210 of the base station 200 may transmit altitude-specific bitmap information (or region-specific bitmap information) and the altitude threshold (or space threshold) using SIB1. The receiving unit 110 of the UE 100 receives the altitude-specific bitmap information (or region-specific bitmap information) and the altitude threshold (or space threshold). For this transmission, an individual RRC message (e.g., an RRC Release message) may be used instead of SIB1. In step S10, if the UE 100 is in an RRC connected state, it may transition to an RRC idle state or an RRC inactive state by receiving the individual RRC message.

[0127] In step S12, the control unit 130 of the UE 100 determines the bitmap information to be applied based on the altitude threshold. If the control unit 130 determines that the UE 100 is located in the sky, it determines to apply the inOneGroup for the sky (and / or the groupPresence for the sky). If the control unit 130 determines that the UE 100 is located on the ground, it determines to apply the inOneGroup for the ground (and / or the groupPresence for the ground). Even if the type is an absolute position in space, the control unit 130 may determine the bitmap information to be applied based on the spatial threshold. In this case, the control unit 130 may identify the UE 100's location (latitude and longitude) using a GNSS (Global Navigation Satellite System) reception function, or may identify the UE 100's location (latitude and longitude) using an RF fingerprint indicating reception quality.

[0128] In step S13, the control unit 130 of the UE 100 performs a cell search using the determined bitmap information.

[0129] (10) Other Operation Examples According to the First Embodiment The first embodiment has been described with respect to a case where the number of SSBs is "64" in half frames. The number of SSBs may be other than "64," for example, "128," "256," "512," etc. In this case, the bitmap information of inOneGroup may be expressed with any bit length, such as 16 bits or 32 bits, instead of 8 bits. Furthermore, groupPresence may also indicate whether or not SSBs are transmitted for any number of consecutive SSB indexes, such as 16 or 32, instead of every 8 consecutive SSB indexes (i.e., one group).

[0130] Second Embodiment Next, a second embodiment will be described, focusing on the differences from the first embodiment.

[0131] In the first embodiment, an example in which the number of SSBs in a half frame is "64" has been described. In this case, for example, if the number of blocks is divided into SSBs for the sky and SSBs for the ground, as shown in Figures 10(C) and 10(D), the number of SSBs for the sky and SSBs for the ground may be less than 64. In other words, it is not possible to use all 64 SSBs for the sky, and it is not possible to use all 64 SSBs for the ground.

[0132] In 6G and the like, the use of the sub-terahertz band (for example, a frequency range of 90 GHz to 300 GHz) is mainly being considered, and in the sub-terahertz band, the number of SSBs in an SS burst is expected to further increase. In addition, advances in antenna technology will enable the provision of thousands of antenna elements on a single antenna panel (or antenna array), enabling simultaneous multiple connections to a large number of UEs 100.

[0133] In such a situation, it is not desirable to limit the number of SSBs.

[0134] On the other hand, let us assume that the number of SSBs is increased from 64 to 128. In this case, even if the 128 SSBs arranged along the time axis are divided into SSBs for the air and SSBs for the ground and transmitted from base station 200 in a time-division manner, both terrestrial UE and UAV UE must wait the time from SSB index #0 to SSB index #127 when performing a cell search. Therefore, it is expected that the time required for cell search will increase for both terrestrial UE and UAV UE.

[0135] Therefore, in the second embodiment, first, the control unit 130 of the base station 200 sets each of a plurality of SSBs that can be simultaneously transmitted at different frequencies within the cell band as a different SSB according to its type, and second, the transmission unit 210 of the base station 200 transmits setting information indicating the setting.

[0136] If the type is altitude, for example, the number of SSBs (e.g., 128) is divided into SSBs for the sky (e.g., 64) and SSBs for the ground (e.g., 64). Then, the transmitter 210 of the base station 200 transmits the SSBs for the sky and the SSBs for the ground simultaneously using different frequencies.

[0137] For example, since the SSB for the air and the SSB for the ground are simultaneously transmitted from the base station 200, the cell search time can be shortened compared to when the SSB for the air and the SSB for the ground are transmitted in a time-division manner. This also makes it possible to reduce the power consumption of the UE 100.

[0138] Furthermore, for example, since SSB for the air and SSB for the ground are transmitted from base station 200 using different frequencies, interference can be suppressed when UE 100 accesses base station 200 (and also in subsequent communications), enabling appropriate communication between UE 100 and base station 200.

[0139] Here, a setting method for setting a plurality of SSBs that can be simultaneously transmitted at different frequencies within a cell band to different SSBs according to type (i.e., a setting method for frequency multiplexed SSB) will be described.

[0140] (1) Method for Setting Frequency Multiplexed SSB FIG. 15 is a diagram illustrating an example of a method for setting frequency multiplexed SSB according to the first embodiment.

[0141] As explained in the first embodiment (FIG. 8), the setting information indicating the SSB parameters (SSB transmission frequency) includes OffsetToPointA, Kssb (ssb-SubcarrierOffset), and absoluteFrequencySSB.

[0142] Therefore, the control unit 230 of the base station 200 may set multiple OffsetToPointA (for example, N, where N is a natural number equal to or greater than 2) within the band of the cell. Alternatively, the control unit 230 may set multiple Kssb (ssb-SubcarrierOffset) within the band of the cell. Alternatively, the control unit 230 may set multiple absoluteFrequencySSB within the standby band of the cell. That is, the control unit 230 sets multiple SSB parameters (multiple SSB transmission frequencies) by using at least one of OffsetToPointA, Kssb (ssb-SubcarrierOffset), and absoluteFrequencySSB as one SSB parameter (SSB transmission frequency). The transmitter 210 of the base station 200 transmits configuration information including multiple SSB parameters (multiple SSB transmission frequencies). That is, the transmitter 210 transmits configuration information including multiple SSB transmission frequencies. The SSB transmission frequencies represent information related to the SSB transmission frequencies for each SSB. The transmitter 210 may transmit the configuration information using any of an MIB, an SIB, and an individual RRC message (e.g., an RRC Reconfiguration message). The receiver 110 of the UE 100 receives the configuration information. Configuration may be performed in this manner.

[0143] 15 shows an example in which two SSB groups (N=2), a first SSB group and a second SSB group, are set. Each SSB group includes at least one SSB. For example, the base station 200 may set the first SSB group as an SSB group for terrestrial use and the second SSB group as an SSB group for aerial use.

[0144] Note that the control unit 230 of the base station 200 may assign an ssb-freqIdx to each SSB group in order to identify each SSB group. The ssb-freqIdx may be a unique number that starts from 0 and increases by one from the lower frequency side to the higher frequency side. The transmission unit 210 of the base station 200 may transmit the ssb-freqIdx to the UE 100 via the PBCH in the SSB. The UE 100 that receives the SSB can identify the ssb-freqIdx of the received SSB (i.e., the frequency at which the received SSB is located from the lowest) based on the PBCH in the received SSB.

[0145] 15 shows an example in which the total number of SSBs is 64, but the total number of SSBs may be 128. In this case, the SSB group represented by ssb-freqIdx=0 may include 64 SSBs, and the SSB group represented by ssb-freqIdx=1 may also include 64 SSBs.

[0146] (2) Communication Method According to the Second Embodiment In the second embodiment, SSBs are set by frequency multiplexing, and each SSB group can be an SSB group according to its type. For example, in FIG. 15 , if the type is altitude, the SSB group represented by ssb-freqIdx = 0 can be an SSB group for the ground, and the SSB group represented by ssb-freqIdx = 1 can be an SSB group for the sky. Alternatively, if the type is absolute position in space, the SSB group represented by ssb-freqIdx = 0 can be an SSB group corresponding to a first region in space, and the SSB group represented by ssb-freqIdx = 1 can be an SSB group corresponding to a second region in space. To which SSB each SSB group corresponds depending on the type, such as whether the SSB group represented by ssb-freqIdx = 1 is an SSB group for the air or an SSB group for the ground, may be transmitted (or set) to UE 100 as correspondence information on the PBCH in the SSB, together with ssb-freqIdx. Alternatively, the correspondence information may be transmitted using MIB, SIB1, or a separate RRC message (for example, an RRCReconfiguration message).

[0147] Note that the transmitter 210 of the base station 200 may transmit an altitude threshold, similar to the first embodiment, to enable identification of altitudes between the sky and the ground. The control unit 130 of the UE 100 can confirm its own altitude based on the altitude threshold and identify an SSB group corresponding to the altitude, similar to the first embodiment. The transmitter 210 may transmit a spatial threshold (e.g., latitude and longitude) instead of the altitude threshold, similar to the first embodiment, and the control unit 130 of the UE 100 can identify an SSB group corresponding to an absolute position in space based on the spatial threshold.

[0148] (3) Example of Bitmap Information In the second embodiment, each SSB group is classified into an SSB group according to its type, and bitmap information indicating whether or not an SSB is transmitted is set.

[0149] In the second embodiment, ssb-PositionInBurst is used as the bitmap information. As described above, ssb-PositionInBurst represents, for example, the position of an SSB in the time domain. Specifically, ssb-PositionInBurst represents whether or not an SSB is to be transmitted for each SSB index (or SSB transmittable timing) of the SSB within an SS burst (one cycle period). ssb-PositionInBurst may include groupPresence and inOneGroup. Alternatively, ssb-PositionInBurst may include, for all SSB indices within the SS burst, a bit representing whether or not an SSB is to be transmitted for each SSB index.

[0150] 16A to 16E are diagrams illustrating an example of an SSB transmission operation according to the second embodiment.

[0151] The examples shown in Figures 16(A) to 16(E) show an example in which the type is altitude, and an ssb-PositionInBurst for the sky ("ssb-PositionInBurstAerial") and an ssb-PositionInBurst for the ground ("ssb-PositionInBurstTerrestrial") are set as the ssb-PositionInBurst. In this case, both the ssb-PositionInBurst for the sky and the ssb-PositionInBurst for the ground may contain the same groupPresence and inOneGroup. Therefore, as shown in Figure 16(D), an SSB for the sky and an SSB for the ground are transmitted at the same timing. As in the first embodiment, the control unit 130 of the UE 100 can use an altitude threshold to apply an ssb-PositionInBurst according to its own altitude. When the control unit 130 of the UE 100 determines that it is located in the sky, it can apply an ssb-PositionInBurst for the sky. In this case, the receiving unit 110 of the UE 100 can check the groupPresence and inOneGroup included in the ssb-PositionInBurst for the sky to check whether or not SSB is transmitted at the SSB transmission timing, and can receive SSB at the SSB transmission timing. Checking whether or not SSB is transmitted using groupPresence and inOneGroup is the same as in the first embodiment. Furthermore, when the control unit 130 of the UE 100 determines that the UE 100 is located on the ground, it applies the terrestrial ssb-PositionInBurst. Then, the receiving unit 110 of the UE 100 can receive the SSB at the SSB transmission timing by checking the groupPresence and inOneGroup included in the terrestrial ssb-PositionInBurst.

[0152] As shown in FIG. 16(C), a conventional ssb-PositionInBurst ("ssb-PositionInBurst") may be set in addition to the ssb-PositionInBurst for the sky and the ssb-PositionInBurst for the ground. As in the first embodiment, it is possible to rescue legacy UEs that cannot process the ssb-PositionInBurst for the sky and the ssb-PositionInBurst for the ground. In this case, as shown in FIG. 16(E), the legacy UE uses the conventional ssb-PositionInBurst to determine whether to transmit an SSB and to receive the SSB.

[0153] (4) Other Examples of Bitmap Information Next, other examples of bitmap information will be described.

[0154] (4-1) Another Example 1 of Bitmap Information In the examples of Figures 16(A) to 16(E), a conventional inOneGroup has been described. As with the first embodiment, an inOneGroup for the sky (e.g., "inOneGroupAerial") and an inOneGroup for the ground (e.g., "inOneGroupTerrestrial") may be set for inOneGroup. In this case, the ssb-PositionInBurst for the sky may include groupPresence and an inOneGroup for the sky, and the ssb-PositionInBurst for the ground may include groupPresence and an inOneGroup for the ground. Since inOneGroup is divided into an inOneGroup for the sky and an inOneGroup for the ground, the transmitter 210 of the base station 200 may transmit the SSB for the sky and the SSB for the ground at different times. When the UE 100 determines that its altitude is in the sky, it can receive the SSB transmitted for the sky without receiving the SSB transmitted as an SSB for the ground by checking the inOneGroup for the sky included in the ssb-PositionInBurst for the sky. Furthermore, when the UE 100 determines that its altitude is on the ground, it can receive the SSB transmitted for the ground without receiving the SSB transmitted as an SSB for the sky by checking the inOneGroup for the ground included in the ssb-PositionInBurst for the ground.

[0155] (4-2) Another Example 2 of Bitmap Information As with the first embodiment, the control unit 230 of the base station 200 may also set groupPresence separately into groupPresence for the sky (for example, "groupPresenceAerial") and groupPresence for the ground ("groupPresenceTerrestrial"). In this case, the ssb-PositionInBurst for the sky includes inOneGroup and groupPresence for the sky, and the ssb-PositionInBurst for the ground includes inOneGroup and groupPresence for the ground. The control unit 130 of the UE 100 selects an ssb-PositionInBurst for the sky or the ground according to its own altitude, and receives the SSB using the groupPresence and inOneGroup included in the selected ssb-PositionInBurst.

[0156] (4-3) Another Example 3 of Bitmap Information Both inOneGroup and groupPresence may be set for the sky and the ground. That is, the control unit 230 of the base station 200 may set an inOneGroup for the sky, an inOneGroup for the ground, a groupPresence for the sky, and a groupPresence for the ground. In this case, the ssb-PositionInBurst for the sky includes an inOneGroup for the sky and a groupPresence for the sky, and the ssb-PositionInBurst for the ground includes an inOneGroup for the ground and a groupPresence for the ground.

[0157] UE100 that has determined that it is located in the sky can properly receive SSBs transmitted as SSBs for the sky by checking the inOneGroup for the sky and the groupPresence for the sky included in the ssb-PositionInBurst for the sky. Also, UE100 that has determined that it is located on the ground can properly receive SSBs transmitted as SSBs for the ground by checking the inOneGroup for the ground and the groupPresence for the ground included in the ssb-PositionInBurst for the ground.

[0158] 16(A) to 16(E) illustrate an example in which altitude is used as the type, but the type is not limited to this and may be expressed as an absolute position in space, as in the first embodiment. In this case, the ssb-PositionInBurst is set to an ssb-PositionInBurst according to the type. For example, instead of the ssb-PositionInBurst for the sky ("ssb-PositionInBurstAerial") shown in FIG. 16(C), an ssb-PositionInBurst corresponding to the first area (e.g., "ssb-PositionInBurstFirstArea") may be used, and instead of the ssb-PositionInBurst for the ground ("ssb-PositionInBurstTerrestrial"), an ssb-PositionInBurst corresponding to the second area (e.g., "ssb-PositionInBurstSecondArea") may be used. The processing in the base station 200 and the UE 100 can also be performed in the same manner as the above-mentioned bitmap example by replacing the ssb-PositionInBurst for the sky with the ssb-PositionInBurst corresponding to the first region and the ssb-PositionInBurst for the ground with the ssb-PositionInBurst corresponding to the second region. When the type is an absolute position in space, a space threshold (for example, latitude and longitude) may be transmitted from the base station 200 to the UE 100 instead of the altitude threshold, as in the first embodiment.

[0159] (4-5) Other Example 5 of Bitmap Information In FIGS. 16(A) to 16(E), an example has been described in which the ssb-PositionInBurst is set to two types, an ssb-PositionInBurst for the sky and an ssb-PositionInBurst for the ground, according to altitude, but this is not limiting. Three or more ssb-PositionInBursts may be set as ssb-PositionInBursts for different altitudes. For example, three types of bitmap information may be set: an ssb-PositionInBurst for the ground, an 1ssb-PositionInBurst for medium altitude, and an ssb-PositionInBurst for high altitude. In this case, in the UE 100, as in the first embodiment, any one of the ssb-PositionInBursts may be applied based on a plurality of altitude thresholds.

[0160] Furthermore, even if the type is an absolute position in space, three or more ssb-PositionInBursts may be set. For example, three pieces of bitmap information may be set: an ssb-PositionInBurst for a first region, an ssb-PositionInBurst for a second region, and an ssb-PositionInBurst for a third region. The UE may apply any one of the ssb-PositionInBursts based on a plurality of spatial thresholds.

[0161] (4-6) Another Example 6 of Bitmap Information As in the first embodiment, each ssb-PositionInBurst may not include groupPresence and inOneGroup, and a bit indicating whether or not an SSB is transmitted may be included for each SSB index in the SS burst. In this case, unlike FIG. 16(D), the base station 200 can set a transmission pattern in which, even at the same timing, an SSB for the sky is transmitted while an SSB for terrestrial use is not transmitted, or an SSB for the sky is not transmitted but an SSB for terrestrial use is transmitted. Even in such a case, the UE 100 can properly receive SSBs transmitted as SSBs for the sky and SSBs transmitted as SSBs for terrestrial use by applying an ssb-PositionInBurst according to its own altitude.

[0162] (5) Operation Example According to Second Embodiment Next, an operation example according to the second embodiment will be described.

[0163] FIG. 17 is a diagram illustrating an example of operation according to the second embodiment.

[0164] As shown in FIG. 17, in step S20, the UE 100 may be in an RRC idle state or an RRC inactive state.

[0165] In step S21, the transmitting unit 210 of the base station 200 transmits the setting information, the bitmap information, and the altitude threshold value.

[0166] First, the configuration information may include a plurality of pieces of information indicating, in resource block units, OffsetToPointA, i.e., the frequency offset between the lowest frequency subcarrier of the corresponding SSB and a reference point of the resource block grid. Alternatively, the configuration information may include a plurality of pieces of information indicating, in subcarrier units, Kssb (ssb-SubcarrierOffset), i.e., the frequency offset between the lowest frequency subcarrier of the corresponding SSB and the lower frequency boundary of the resource block to which the subcarrier belongs. Alternatively, the configuration information may include a plurality of pieces of information indicating absoluteFrequencySSB (ARFCN), i.e., the frequency of the corresponding SSB.

[0167] Second, the bitmap information includes bitmap information about ssb-PositionInBurst, which includes a plurality of ssb-PositionInBursts that differ depending on the type (specifically, altitude or absolute position in space).

[0168] Third, if the type is a spatial absolute value, a spatial threshold is transmitted instead of an altitude threshold.

[0169] Fourth, the transmitting unit 210 of the base station 200 may transmit (broadcast) the configuration information, bitmap information, and altitude threshold by including them in the MIB, or may transmit (broadcast) them in the SIB1, or may transmit them in an individual RRC message (for example, an RRC release message). In the case of an individual RRC message, the UE 100 may transition from the RRC connected state to the RRC idle state (or the RRC inactive state) in response to receiving the individual RRC message. As shown in the current 3GPP specifications, part of the configuration information (Kssb (ssb-SubcarrierOffset)) may be transmitted in the MIB, and the rest may be transmitted in the SIB1. The receiving unit 110 of the UE 100 receives the configuration information, bitmap information, and altitude threshold.

[0170] In step S22, the control unit 130 of the UE 100 determines the SSB transmission frequency information and bitmap information to be applied based on the altitude threshold.

[0171] In step S23, the receiver 110 of the UE 100 applies the determined SSB transmission frequency and the determined bitmap information to receive the SSB and perform a cell search.

[0172] (6) Other Operation Examples According to the Second Embodiment In the second embodiment, the number of SSBs in a half frame is described as "128." The number of SSBs may be other than "128," for example, "64," "256," "512," etc. In this case, the bitmap information of inOneGroup may be expressed as any bit length, such as 16 bits or 32 bits, instead of 8 bits, as in the first embodiment. Furthermore, as in the first embodiment, groupPresence may also indicate whether or not an SSB is to be transmitted for any number of consecutive SSB indexes, such as 16 or 32, instead of every 8 consecutive SSB indexes (i.e., one group).

[0173] Third Embodiment Next, a third embodiment will be described, focusing on the differences between the first and second embodiments.

[0174] 18 is a diagram illustrating a scenario according to the third embodiment. The following scenario is assumed. That is, base station 200 simultaneously transmits SSB #1 included in SSB group A and SSB #65 included in SSB group B using different frequencies. Base station 200 transmits SSB group A with a wide beam and transmits SSB group B with a narrow beam. A wide beam is a beam with a certain beam width or more. A narrow beam is a beam with a beam width less than a certain width. While UE 100 is moving at a speed greater than a certain speed (i.e., high speed), it initiates a random access procedure to the network at the point shown in FIG. 18.

[0175] In the above scenario, UE100 is expected to select narrow beam SSB#65 at the point shown in Figure 18 because the RSRP measurement value of SSB#1 is higher than the RSRP measurement value of SSB#65. However, if UE100 selects SSB#65, it may move outside the narrow beam area during the random access procedure (or during cell search), which may cause the random access procedure (or cell search) to fail. Therefore, taking into account the movement state of UE100, UE100 should select wide beam SSB#1.

[0176] In the third embodiment, similarly to the second embodiment, multiple SSB groups are simultaneously transmitted using different frequencies. At this time, for example, SSB group A is transmitted using a wide beam, and SSB group B is transmitted using a narrow beam. That is, the SSBs can be configured as different SSB groups depending on the beam type. The beam type may include a wide beam and a narrow beam. Alternatively, the beam type may include three or more types of beams including a wide beam and a narrow beam. In the third embodiment, base station 200 transmits priority information to UE 100 to enable UE 100 to select SSB group A with priority over SSB group B.

[0177] Specifically, the control unit 230 of the base station 200 sets each of a plurality of synchronization signal blocks that can be simultaneously transmitted at different frequencies within the cell band as a different synchronization signal block according to the beam type. Then, the transmission unit 210 of the base station 200 transmits priority information indicating information for prioritizing the second synchronization signal block group over the first synchronization signal block group for the first synchronization signal block group and the second synchronization signal block group that have been set as different synchronization signal block groups for each frequency.

[0178] For example, by grouping SSBs according to beam type, base station 200 can transmit each of multiple SSB groups using narrow beams and wide beams. Then, for example, based on priority information, UE 100 selects a wide beam over a narrow beam and performs cell search and random access procedures using the SSBs transmitted using the wide beam. This allows cell search and random access procedures to be performed continuously without interruption, even when UE 100 is moving at high speed. By performing cell search continuously without interruption in this manner, in the third embodiment as well, as in the first embodiment, the efficiency of cell search can be improved and power consumption of UE 100 can be reduced.

[0179] Here, the SSB groups according to the beam types used in the third embodiment will be described.

[0180] (1) SSB Groups According to Beam Type As explained in the second embodiment, it is possible to set multiple SSB groups that can be transmitted simultaneously at different frequencies using configuration information including multiple SSB transmission frequency information ( FIG. 15 ). The configuration information may include at least one of multiple OffsetToPointA, multiple Kssb (ssb-SubcarrierOffset), and multiple absoluteFrequencySSB (ARFCN).

[0181] For example, when two SSB groups are set, the base station 200 transmits the SSBs included in one SSB group using a wide beam and transmits the SSBs included in the other SSB group using a narrow beam. The base station 200 may form the wide beam and the narrow beam using a known beamforming technique. When three or more SSB groups are set, the base station 200 may transmit each SSB group using a different beam type.

[0182] In this way, the control unit 230 of the base station 200 groups the SSBs into multiple SSB groups and sets the beam type to be used to transmit each SSB group. This allows the transmission unit 210 of the base station 200 to transmit according to the beam type for each SSB group in accordance with the settings. The transmission unit 210 may transmit setting information, as in the second embodiment. The transmission unit 210 may also transmit beam type information indicating the beam type to be used to transmit each SSB group. The beam type information may be transmitted in an MIB, an SIB, or an individual RRC message (e.g., an RRC reconfiguration message). The reception unit 110 of the UE 100 may receive the beam type information.

[0183] (2) Priority Information In the third embodiment, priority information is applied to the UE 100 to enable the UE 100 to select an SSB group with priority over another SSB group.

[0184] First, the priority information includes condition information indicating a condition for determining the state of the UE 100. Specifically, the condition information may be a speed threshold related to the movement speed of the UE 100. For example, the control unit 130 of the UE 100 determines that the UE 100 is in a high-mobility state when the movement speed of the UE 100 is equal to or greater than the speed threshold, and determines that the UE 100 is not in a high-mobility state when the movement speed of the UE 100 is less than the speed threshold. The movement speed may be expressed as a relative speed of the UE 100 with respect to the base station 200. Alternatively, the condition information may indicate that the UE 100 is in an on-board state. The on-board state may be detected, for example, when the AS layer of the UE 100 is notified by the application layer that the UE 100 is in the on-board state. For example, the application layer of the UE 100 may detect that the UE 100 has passed through an automatic ticket gate at a station and notify the UE 100 of the on-board state.

[0185] The condition information may be linked to an SSB group. When in a high-speed moving state (or on-board state), it may be linked to SSB group A, and when not in a high-speed moving state (or not in an on-board state), it may be linked to SSB group B. In this case, when UE 100 determines that it is in a high-speed moving state (or on-board state) based on the condition information, it selects SSB group A, and when it is not in a high-speed moving state (or on-board state), it selects SSB group B.

[0186] Second, the priority information includes priority method information indicating a method for prioritizing an SSB group over other SSB groups. Specifically, the priority method information may be information representing exclusive selection, indicating that if a certain SSB group is selected based on the condition information, other SSB groups are not selected. For example, if SSB group A is selected based on the condition information, the priority method information may represent information representing the priority of each SSB group. For example, the priority of SSB group A may be "7," the priority of SSB group B may be "3," and the priority of SSB group C may be "0." Alternatively, the priority method information may be an offset value for the reception quality value. For example, if SSB group A is selected based on the condition information, an offset value of "6 dB" is applied to the reception quality value of the SSBs included in SSB group A, and no offset value is applied to the reception quality values ​​of the SSBs included in the other SSB groups. The reception quality value may be represented by RSRP, RSSI (Received Signal Strength Indicator), RSRQ (Reference Signal Received Quality), or SINR (Signal to Interference plus Noise Ratio).

[0187] The priority method information may be associated with each SSB group. For example, if SSB group A is selected based on the condition information, the information representing the priority may indicate that the priority of SSB group A is "7" and the priority of SSB group B is "3." However, if SSB group B is selected based on the condition information, the information representing the priority may indicate that the priority of SSB group A is "3" and the priority of SSB group B is "7." In this way, different priorities may be assigned depending on the SSB group selected based on the condition information. Even if the priority method information includes an offset value for the reception quality value, different offset values ​​may be applied depending on the SSB group selected based on the condition information.

[0188] Further, the priority method information may be linked to the condition information. For example, information (or an offset value for the reception quality value) representing the priority when the moving speed of the UE 100 is equal to or greater than a threshold may be different from information (or an offset value for the reception quality value) representing the priority when the moving speed of the UE 100 is less than a threshold. Alternatively, for example, information (or an offset value for the reception quality value) representing the priority when the state of the UE 100 is on-board may be different from information (or an offset value for the reception quality value) representing the priority when the state of the UE 100 is not on-board.

[0189] (3) Bitmap Information According to Beam Type In the third embodiment, a plurality of pieces of bitmap information according to beam types may be set. The bitmap information may be ssb-PositonInBurst. In this case, similar to the second embodiment, different ssb-PositonInBursts are set according to the beam types.

[0190] 19(A) to 19(E) are diagrams showing examples of SSB transmission operations according to the third embodiment. FIG. 19(C) shows an example in which an ssb-PositonInBurst for a wide beam (the "A" in "ssb-PositonInBurstA" may be "Wide") and an ssb-PositonInBurst for a narrow beam (the "B" in "ssb-PositonInBurstB" may be "Narrow") are set. When an SSB (or a group of SSBs) using a wide beam and an SSB (or a group of SSBs) using a narrow beam are simultaneously transmitted at different frequencies, the ssb-PositonInBurst for the wide beam and the ssb-PositonInBurst for the narrow beam indicate whether or not an SSB is to be transmitted for each beam type.

[0191] Note that the bitmap information may be any of the other examples of bitmap information described in the first and second embodiments.

[0192] That is, even in the third embodiment, as shown in FIG. 19(C), a conventional ssb-PositionInBurst ("ssb-PositionInBurst") may be set for legacy UEs that cannot process the ssb-PositionInBurst for a wide beam and the ssb-PositionInBurst for a narrow beam.

[0193] Furthermore, for groupPresence, a groupPresence for a wide beam (for example, "groupPresenceWide") and a groupPresence for a narrow beam (for example, "groupPresenceNarrow") may be set.

[0194] Alternatively, for inOneGroup, an inOneGroup for a wide beam (for example, "inOneGroupWide") and an inOneGroup for a narrow beam (for example, "inOneGroupNarrow") may be set.

[0195] Alternatively, groupPresence and inOneGroup for wide beam and narrow beam may be set for both groupPresence and inOneGroup. That is, ssb-PositonInBurst for wide beam includes groupPresence for wide beam and groupPresence for narrow beam. Also, ssb-PositonInBurst for narrow beam may include groupPresence for narrow beam and inOneGroup for narrow beam.

[0196] Alternatively, ssb-PositionInBurst may be bitmap information that does not include groupPresence and inOneGroup, and that indicates with a bit whether or not an SSB is being transmitted for each SSB index in the burst.

[0197] Alternatively, three or more different types of ssb-PositionInBurst may be set according to the beam type. Alternatively, multiple ssb-PositionInBursts may be grouped not only on the frequency axis but also on the time axis. For example, when a wide beam and a narrow beam are transmitted in a time-division manner, an ssb-PositionInBurst for the wide beam and an ssb-PositionInBurst for the narrow beam may be set (or transmitted).

[0198] (4) Operation Example According to Third Embodiment Next, an operation example according to the third embodiment will be described.

[0199] FIG. 20 is a diagram illustrating an example of operation according to the third embodiment.

[0200] As shown in FIG. 20, in step S30, the UE 100 is in an RRC idle state or an RRC inactive state.

[0201] In step S31, the transmitter 120 of the base station 200 transmits SSB group related information. The SSB group related information includes configuration information, bitmap information, and priority information. The transmitter 120 may transmit the SSB group related information using an MIB or an SIB. The transmitter 120 may transmit part of the configuration information (e.g., Kssb (ssb-SubcarrierOffset)) using the MIB, and transmit the remaining part of the configuration information using SIB1. The receiver 110 of the UE 100 receives the SSB group related information.

[0202] In step S32, the control unit 130 of the UE 100 selects an SSB group based on the priority information.

[0203] First, the control unit 130 identifies the state of the UE 100 itself based on the condition information included in the priority information. For example, the control unit 130 measures its own moving speed using a GNSS receiver or a speed sensor. The control unit 130 determines whether or not the UE 100 is in a high-speed moving state based on a speed threshold included in the condition information. Alternatively, if the condition information indicates an on-board state, the control unit 130 may determine whether or not a notification indicating the on-board state has been received from the application layer.

[0204] Second, the control unit 130 selects an SSB group linked to the condition information. For example, when the control unit 130 determines that its own state is a high-speed movement state, it may select an SSB group linked to the high-speed movement state (e.g., SSB group A for wide beams), and when its own state is not a high-speed movement state, it may select another SSB group (e.g., SSB group B for narrow beams). For example, when the control unit 130 is in an on-board state, it may select an SSB group linked to the on-board state (e.g., SSB group A for wide beams), and when its own state is not an on-board state, it may select another SSB group (e.g., SSB group B for narrow beams).

[0205] Third, the control unit 130 selects an SSB group in accordance with the priority method information included in the priority information.

[0206] For example, if the priority method information includes exclusive information, the SSB group selected based on the condition information is selected, and other SSB groups are not selected. For example, if the control unit 130 selects SSB group A for a wide beam based on the condition information, it selects SSB group A for the wide beam in accordance with the exclusive information, and does not select SSB group B for a narrow beam.

[0207] Alternatively, if the priority method information includes a priority, the control unit 130 selects the SSB group with the highest priority. For example, if the control unit 130 selects SSB group A for a wide beam according to the condition information, the control unit 130 applies information indicating the priority associated with SSB group A (the priority of SSB group A is "7", and the priority of SSB group B is "3") to select SSB group A for a wide beam with the highest priority. For example, if the control unit 130 selects SSB group B for a narrow beam according to the condition information, the control unit 130 applies information indicating the priority associated with SSB group B (the priority of SSB group A is "3", and the priority of SSB group B is "7") to select SSB group B for a narrow beam with the highest priority.

[0208] Alternatively, if the priority method information includes an offset value for the reception quality value, the control unit 130 determines an offset value for the reception quality for each SSB group. For example, if the control unit 130 selects SSB group A for a wide beam in accordance with the condition information, the control unit 130 determines to apply the offset value associated with SSB group A (e.g., apply an offset of "6 dB" to the reception quality value for the SSBs of SSB group A, and do not apply an offset value to the reception quality value for the SSBs of SSB group B). Also, for example, if the control unit 130 selects SSB group B for a narrow beam in accordance with the condition information, the control unit 130 determines to apply the offset value associated with SSB group B (e.g., do not apply an offset value to the reception quality value for the SSBs of SSB group A, and apply an offset value of "6 dB" to the reception quality value for the SSBs of SSB group B). The offset value is applied when actually measuring reception quality during cell search.

[0209] In step S33, the transmitter 120 of the UE 100 receives the SSBs included in the SSB group selected in step S32. At this time, the transmitter 120 receives each SSB according to the bitmap information. Specifically, if the transmitter 120 selects SSB group A for a wide beam in step S32, the transmitter 120 receives the SSBs transmitted in the wide beam at the timing of each SSB index (i.e., the transmission timing of each SSB) using the ssb-PositionInBurst for the wide beam. Alternatively, if the transmitter 120 selects SSB group B for a narrow beam in step S32, the transmitter 120 receives the SSBs transmitted in the narrow beam at the timing of each SSB index (i.e., the transmission timing of each SSB) using the ssb-PositionInBurst for the narrow beam. In this case, if the priority method information includes an offset value for reception quality, the control unit 130 (or the receiving unit 110) applies the offset value to the reception quality (e.g., RSRP measurement value) of the received SSB and selects one of the multiple SSB groups.

[0210] The control unit 130 (or the receiving unit 110) then selects the SSB with the best reception quality from the selected group of SSBs. The control unit 130 then performs a random access procedure using the PRACH resource (specifically, the RA occasion) associated with the selected SSB, and executes a procedure (e.g., an RRC setup procedure or an RRC resume procedure) for establishing an RRC connection with the base station 200.

[0211] For example, in the scenario shown in FIG. 18 , if the movement speed of UE 100 satisfies the condition information (e.g., the movement speed is equal to or greater than a speed threshold), SSB group A for the wide beam can be selected according to the preferred method information (e.g., priority). As a result, UE 100 can perform a cell search using SSB #1 of SSB group A transmitted using a wide beam and perform a random access procedure using this SSB. In this case, UE 100 does not use SSB #65 of SSB group B transmitted using a narrow beam, and can therefore perform the cell search and random access procedure continuously. As a result, for example, UE 100 can efficiently perform the cell search and random access procedure without interruption, enabling appropriate communication with base station 200.

[0212] (5) Another Operation Example 1 According to the Third Embodiment In the third embodiment, an example has been described in which priority selection is performed for each SSB group based on priority information. For example, priority selection may be performed for each SSB based on priority information. For example, condition information may be associated with each SSB, and the control unit 130 of the UE 100 may select one of the SSBs when the state of the UE 100 satisfies the condition information, and may select another SSB when the state of the UE 100 does not satisfy the condition information. Furthermore, the priority of the priority method information may also be set for each SSB, and an offset value for the reception quality of the SSB may also be set for each SSB.

[0213] (6) Another Operation Example 2 According to the Third Embodiment In the third embodiment, the number of SSBs is described as "128" in half frames. The number of SSBs may be other than "128," for example, "256," "512," etc. In this case, the bitmap information of inOneGroup may be expressed as any bit length, such as 16 bits or 32 bits, instead of 8 bits. Furthermore, groupPresence may also indicate whether or not SSBs are transmitted for any number of consecutive SSB indexes, such as 16 or 32, instead of every 8 consecutive SSB indexes (i.e., one group).

[0214] Fourth Embodiment Next, a fourth embodiment will be described, focusing on the differences from the first to third embodiments.

[0215] When the distance from base station 200 is less than the distance threshold (i.e., short distance), the reception quality of UE100 is sufficient, so there is no significant difference in reception quality whether UE100 selects a wide beam or a narrow beam. Strictly speaking, at the same point, the reception quality of a narrow beam is better than that of a wide beam, so UE100 is more likely to select a narrow beam. Therefore, as described in the third embodiment, it is desirable for UE100 to select a wide beam if it is moving at high speed in accordance with the priority information.

[0216] In general, the beam formed in base station 200 becomes wider as the distance from base station 200 increases. Therefore, when the distance from base station 200 is equal to or greater than the distance threshold (i.e., a long distance), even if UE 100 selects a narrow beam, beam switching is less likely to occur compared to when the distance from base station 200 is less than the distance threshold.

[0217] From the viewpoint of distance from the base station 200, it can be said that it is better to give priority to using a wide beam for the UE 100 whose distance from the base station 200 is less than the distance threshold. It can also be said that priority can be given to using a narrow beam for the UE 100 whose distance from the base station 200 is equal to or greater than the distance threshold.

[0218] (1) Bitmap Information Therefore, in the fourth embodiment, first, the base station 200 sets a plurality of different bitmap information depending on the relative position of the UE 100 with respect to the base station 200. Specifically, the transmitter 210 of the base station 200 transmits a plurality of bitmap information indicating whether or not to transmit a synchronization signal block within an SS burst period (one frequency period) of a predetermined frequency, and the bitmap information differs depending on the relative position of the UE 100 with respect to the base station 200.

[0219] 21(A) to 21(E) are diagrams illustrating an example of an SSB transmission operation according to the fourth embodiment. The relative position may be the distance of the UE 100 to the base station 200. As the bitmap information according to the fourth embodiment, a plurality of different bitmap information is set according to the distance. Specifically, bitmap information for a short distance and bitmap information for a long distance may be set.

[0220] FIG. 21B shows an example in which, as bitmap information, inOneGroup is set to inOneGroup for long distance ("inOneGroupFar") and inOneGroup for short distance ("inOneGroupNear"). A distance threshold for specifying in UE 100 either inOneGroup for long distance or inOneGroup for short distance is transmitted from transmission unit 210 of base station 200. Control unit 130 of UE 100 specifies either inOneGroup for long distance or inOneGroup for short distance based on the distance threshold. Control unit 130 measures the distance to base station 200 by using a GNSS reception function, an RF fingerprint, Timing Advance, or the like. Then, the control unit 130 compares the measured distance with a distance threshold to determine which inOneGroup to apply.

[0221] As shown in Fig. 21(D), base station 200 transmits long-distance SSBs and short-distance SSBs in a time-division manner. UE 100 that has decided to apply long-distance inOneGroup can receive the long-distance SSBs without receiving the short-distance SSBs by checking long-distance inOneGroup in receiver 110. UE 100 that has decided to apply short-distance inOneGroup can receive the short-distance SSBs without receiving the long-distance SSBs by checking short-distance inOneGroup in receiver 110.

[0222] Similarly, for groupPresence, a plurality of different groupPresences may be set as bitmap information according to the relative positions.

[0223] 22(A) to 22(E) are diagrams showing an example of SSB transmission operation according to the fourth embodiment. Fig. 22(A) shows an example in which a long-distance groupPresence ("groupPresenceFar") and a short-distance groupPresence ("groupPresenceNear") are set. The control unit 130 of the UE 100 identifies either the long-distance groupPresence or the short-distance groupPresence based on the distance threshold, and determines which one to apply. UE 100 that has decided to apply long-distance groupPresence checks long-distance groupPresence using receiving unit 110 (or control unit 130), and if it is "1", determines that the group has SSB transmission, and further checks inOneGroup within the group to check whether SSB transmission is occurring in units of SSB index. UE 100 that has decided to apply short-distance groupPresence checks short-distance groupPresence using receiving unit 110, and if it is "1", determines that the group has SSB transmission, and further checks inOneGroup within the group to check whether SSB transmission is occurring in units of SSB index. If the groupPresence is "0" whether it is for long distance or short distance, the receiving unit 110 of the UE 100 determines that the group is not transmitting SSB, and does not check inOneGroup.

[0224] As a result, for example, UE 100 can appropriately receive SSBs transmitted at different timings depending on the distance by using bitmap information according to the distance, and can efficiently perform cell search.

[0225] Note that, with regard to the bitmap information, similarly to the first embodiment, both inOneGroup and groupPresence may include long-distance and short-distance versions. Also, similarly to the first embodiment, the conventional inOneGroup and / or conventional groupPresence may be transmitted to the UE 100 as bitmap information to rescue legacy UEs. Other examples of bitmap information related to inOneGroup and groupPresence may be applied to the fourth embodiment as well, similarly to the first embodiment.

[0226] (2) Setting information In the fourth embodiment, secondly, the base station 200 may set multiple SSB groups that can be transmitted simultaneously using different frequencies within the cell band, and set each of the multiple SSB groups to be a different SSB group depending on the relative position.

[0227] Specifically, the control unit 230 of the base station 200 may set a long-distance SSB group and a short-distance SSB group. The transmission unit 210 of the base station 200 simultaneously transmits the SSBs included in the long-distance SSB group and the SSBs included in the short-distance SSB group using different frequencies. The transmission unit 210 can perform configuration (or transmission) for the UE 100 using configuration information, as in the second embodiment. The configuration information may include multiple OffsetToPointA, as in the second embodiment. Alternatively, the configuration information may include multiple Kssb (ssb-SubcarrierOffset). Alternatively, the configuration information may include multiple absoluteFrequencySSB.

[0228] Furthermore, in the fourth embodiment, bitmap information corresponding to each SSB group may be set, similar to the second embodiment.

[0229] For example, in FIG. 19(C), "ssb-PositionInBurst#A" may be an SSB-PositionInBurst for short distances (e.g., "ssb-PositionInBurstNear"), and "ssb-PositionInBurst#B" may be an SSB-PositionInBurst for long distances (e.g., "ssb-PositionInBurstFar"). As shown in FIG. 19(D), the transmitter 210 of the base station 200 simultaneously transmits an SSB for short distances and an SSB for long distances using different frequencies. At this time, the transmitter 210 transmits the SSB for short distances using a wide beam, and transmits the SSB for long distances using a narrow beam.

[0230] The control unit 130 of the UE 100 identifies either the short-distance ssb-PositionInBurst or the long-distance ssb-PositionInBurst based on the distance threshold, and decides to apply either one. When it is decided to apply the short-distance ssb-PositionInBurst, the receiving unit 110 of the UE 100 checks the inOneGroup and groupPresence included in the short-distance ssb-PositionInBurst, and checks whether or not an SSB is to be transmitted for each SSB index (i.e., for each SSB transmittable timing). On the other hand, when it is decided to apply the long-distance ssb-PositionInBurst, the receiving unit 110 checks the inOneGroup and groupPresence included in the long-distance ssb-PositionInBurst, and checks whether or not an SSB is to be transmitted for each SSB index (i.e., for each SSB transmittable timing). The receiving unit 110 receives the SSB at the SSB transmission timing.

[0231] As a result, for example, even if UE 100 is located at a "long distance" from base station 200, SSB is transmitted using a narrow beam, so beam switching is less likely to occur in UE 100 compared to when SSB is transmitted using a narrow beam when UE 100 is located at a "short distance". Therefore, UE 100 can continuously perform cell search, and can perform cell search efficiently.

[0232] Furthermore, in the fourth embodiment, as in the second embodiment, even if the number of SSBs increases, the SSBs are transmitted simultaneously using different frequencies, so that the UE 100 can reduce the time required for cell search compared to when different SSBs are received in a time-division manner, thereby making the cell search more efficient.

[0233] Regarding the ssb-PositionInBurst, other examples of the ssb-PositionInBurst described in the first embodiment can also be applied to the fourth embodiment, such as transmitting a conventional ssb-PositionInBurst from the base station 200 to rescue legacy UEs. Furthermore, for example, the ssb-PositionInBurst may be grouped on the time axis, as in the third embodiment. For example, when a long-distance SSB and a short-distance SSB are transmitted in a time-division manner, a short-distance ssb-PositionInBurst and a long-distance ssb-PositionInBurst may be set (or transmitted).

[0234] (3) Operation example according to the fourth embodiment The operation example according to the fourth embodiment can be implemented by replacing the "bitmap information by altitude" with "bitmap information according to relative position" and the "altitude threshold" with "distance threshold" in the operation example (FIG. 14) described in the first embodiment.

[0235] Furthermore, the operation example of the fourth embodiment can be implemented by replacing the "altitude threshold" with "distance threshold" in the operation example (FIG. 17) described in the second embodiment. In this case, the setting information is setting information for multiple SSB groups that differ depending on the relative position (e.g., distance). Furthermore, the bitmap information is multiple bitmap information that differ depending on the relative position (e.g., distance).

[0236] (4) Other Operation Examples According to the Fourth Embodiment The fourth embodiment has been described with respect to the case where the number of SSBs is "64" or "128" in a half frame. Other SSB numbers may be used, such as "256," "512," etc. In this case, the bitmap information of inOneGroup may be expressed with any bit length, such as 16 bits or 32 bits, instead of 8 bits. Furthermore, groupPresence may also indicate whether or not SSBs are transmitted for any number of consecutive SSB indexes, such as 16 or 32, instead of every 8 consecutive SSB indexes (i.e., one group).

[0237] [Other Embodiments] The above-described operational flows are not limited to being implemented independently, but can be implemented by combining two or more operational flows. For example, some steps of one operational flow may be added to another operational flow, or some steps of one operational flow may be replaced with some steps of another operational flow. In each flow, it is not necessary to execute all steps, and only some steps may be executed.

[0238] In the above embodiment, an example in which the base station is an NR base station (gNB) has been described, but the base station may be an LTE base station (eNB) or a 6G base station. The base station may also be a relay node such as an IAB (Integrated Access and Backhaul) node. The base station may also be a DU of the IAB node. The UE 100 may also be an MT (Mobile Termination) of the IAB node.

[0239] The term "network node" primarily refers to a base station, but may also refer to a core network device or a part of a base station (CU, DU, or RU). A network node may also be configured by a combination of at least a part of a core network device and at least a part of a base station.

[0240] A program may be provided that causes a computer to execute each process performed by the UE 100 or the base station 200. The program may be recorded on a computer-readable medium. Using the computer-readable medium, the program can be installed on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM. Furthermore, circuits that execute each process performed by the UE 100 or the base station 200 may be integrated, and at least a part of the UE 100 or the base station 200 may be configured as a semiconductor integrated circuit (chip set, SoC).

[0241] As used in this disclosure, the terms "based on" and "depending on / in response to" do not mean "based only on" or "depending only on," unless expressly stated otherwise. The term "based on" means both "based only on" and "based at least in part on." Similarly, the term "depending on" means both "depending only on" and "depending at least in part on." The terms "include," "comprise," and variations thereof do not mean including only the listed items, but may mean including only the listed items or may include additional items in addition to the listed items. Additionally, the term "or," as used in this disclosure, is not intended to mean an exclusive or. Furthermore, any reference to elements using designations such as "first," "second," etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used herein as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way. In this disclosure, where articles are added by translation, such as a, an, and the in English, these articles shall include the plural unless the context clearly indicates otherwise.

[0242] Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes can be made within the scope of the gist. Furthermore, the embodiments, operation examples, and processes can be appropriately combined within the scope of not being inconsistent.

[0243] The functions performed by the UE 100 or base station 200 (network node) may be implemented in circuitry or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), a CPU (a Central Processing Unit), conventional circuits, and / or combinations thereof, programmed to perform the described functions. A processor includes transistors and other circuits and is considered to be circuitry or processing circuitry. A processor may also be a programmed processor that executes a program stored in a memory.

[0244] In this specification, a circuitry, unit, or means is hardware that is programmed to realize or performs the described functions, which may be any hardware disclosed herein or any hardware known to be programmed to realize or perform the described functions.

[0245] If the hardware is a processor considered to be a type of circuitry, the circuitry, means, or unit is a combination of hardware and software used to configure the hardware and / or processor.

[0246] (Additional Note)

[0247] (Supplementary Note 1) A network node that manages a cell in a mobile communication system, comprising: a control unit that sets each of a plurality of synchronization signal blocks that can be transmitted simultaneously at different frequencies within the band of the cell as a different synchronization signal block according to a beam type; and a transmission unit that transmits setting information representing the setting.

[0248] (Supplementary Note 2) The network node according to Supplementary Note 1, wherein the transmitter transmits priority information representing information for prioritizing the second synchronization signal block group over the first synchronization signal block group for a first synchronization signal block group and a second synchronization signal block group, the first synchronization signal block group and the second synchronization signal block group being set as different synchronization signal block groups for each frequency, each of which includes at least one of the synchronization signal blocks.

[0249] (Supplementary Note 3) The network node according to Supplementary Note 1 or Supplementary Note 2, wherein the priority information includes condition information representing a condition for determining a state of a user equipment.

[0250] (Supplementary Note 4) The network node according to any one of Supplementary Notes 1 to 3, wherein the condition information includes a threshold value of a moving speed of the user equipment.

[0251] (Supplementary Note 5) The network node according to any one of Supplementary Notes 1 to 4, wherein the priority information includes priority method information representing a method for prioritizing the second synchronization signal block group over the first synchronization signal block group.

[0252] (Supplementary Note 6) A network node as described in any of Supplementary Notes 1 to 5, wherein the priority method information is at least one of: exclusive information indicating that the second synchronization signal block group selected based on the condition information is selected and that the first synchronization signal block group is not selected; information indicating the priority of the first synchronization signal block group and the second synchronization signal block group; and an offset value for the reception quality value of the synchronization signal block included in the first synchronization signal block group and / or an offset value for the reception quality value of the synchronization signal block included in the second synchronization signal block group.

[0253] (Supplementary Note 7) The network node according to any one of Supplementary Note 1 to Supplementary Note 6, wherein the beam type is at least one of a wide beam having a beam width equal to or greater than a certain value and a narrow beam having a beam width less than a certain value.

[0254] (Supplementary Note 8) A network node as described in any one of Supplementary Notes 1 to 7, wherein the transmitting unit transmits a plurality of bitmap information indicating whether or not to transmit the synchronization signal block at each transmittable timing of the synchronization signal block within one cycle period, the bitmap information differing for each frequency depending on the beam type.

[0255] (Supplementary Note 9) The network node according to any one of Supplementary Notes 1 to 8, wherein the bitmap information is ssb-PositonInBurst.

[0256] (Supplementary Note 10) A user device that performs wireless communication with a network node that manages a cell in a mobile communication system, the user device having a receiving unit that receives setting information from the network node for setting each of a plurality of synchronization signal blocks that can be transmitted simultaneously at different frequencies within the band of the cell as a different synchronization signal block according to a beam type.

[0257] (Supplementary Note 11) The user device according to Supplementary Note 10, wherein the receiving unit receives priority information from the network node, the priority information representing information for prioritizing the second synchronization signal block group over the first synchronization signal block group, for a first synchronization signal block group and a second synchronization signal block group set as different synchronization signal block groups for each frequency, the second synchronization signal block group including at least one of the synchronization signal blocks.

[0258] (Supplementary Note 12) The user device according to Supplementary Note 10 or Supplementary Note 11, wherein the priority information includes condition information representing a condition for determining a state of the user device.

[0259] (Supplementary Note 13) The user device according to any one of Supplementary Notes 10 to 12, wherein the condition information includes a threshold value of a moving speed of the user device.

[0260] (Supplementary Note 14) The user equipment according to any one of Supplementary Notes 10 to 13, wherein the priority information includes priority method information representing a method for prioritizing the second synchronization signal block group over the first synchronization signal block group.

[0261] (Supplementary Note 15) A user device as described in any of Supplementary Notes 10 to 14, wherein the priority method information is at least one of: exclusive information indicating that the second synchronization signal block group selected based on the condition information is selected and that the first synchronization signal block group is not selected; information indicating the priority of the first synchronization signal block group and the second synchronization signal block group; and an offset value for the reception quality value of the synchronization signal block included in the first synchronization signal block group and / or an offset value for the reception quality value of the synchronization signal block included in the second synchronization signal block group.

[0262] (Supplementary Note 16) The user device according to any one of Supplementary Note 10 to Supplementary Note 15, wherein the beam type is at least one of a wide beam having a beam width equal to or greater than a certain value and a narrow beam having a beam width less than a certain value.

[0263] (Supplementary Note 17) The user device according to any one of Supplementary Notes 10 to 16, wherein the receiving unit receives a plurality of bitmap information pieces that are bitmap information pieces indicating whether or not to transmit the synchronization signal block at each transmittable timing of the synchronization signal block within one cycle period, and that differ for each frequency depending on the beam type.

[0264] (Supplementary Note 18) The user device according to any one of Supplementary Notes 10 to 17, wherein the bitmap information is ssb-PositonInBurst.

[0265] (Supplementary Note 19) A communication method used in a network node that manages a cell in a mobile communication system, comprising the steps of: setting each of a plurality of synchronization signal blocks that can be transmitted simultaneously at different frequencies within the band of the cell as a different synchronization signal block according to a beam type; and transmitting setting information representing the setting.

[0266] (Supplementary Note 20) A communication method used by a user device that performs wireless communication with a network node that manages a cell in a mobile communication system, the communication method comprising: a step of receiving, from the network node, configuration information for setting each of a plurality of synchronization signal blocks that can be transmitted simultaneously at different frequencies within the band of the cell as a different synchronization signal block according to a beam type.

[0267] 10: Network 20: RAN 30: CN 100: UE 110: Receiving unit 120: Transmitting unit 130: Control unit 140: Wireless communication unit 200: Base station 210: Transmitting unit 220: Receiving unit 230: Control unit 240: NW communication unit 250: Wireless communication unit 300: CN device

Claims

1. A network node that manages cells in a mobile communication system, A control unit that sets each of a plurality of synchronization signal blocks that can be transmitted simultaneously at different frequencies within the bandwidth of the cell as a different synchronization signal block according to the beam type, It has a transmitting unit that transmits setting information representing the aforementioned setting, The transmitting unit transmits priority information to a first group of synchronization signal blocks and a second group of synchronization signal blocks, which are set as different groups of synchronization signal blocks for each frequency, and which include at least one of the synchronization signal blocks, indicating that the second group of synchronization signal blocks is given priority over the first group of synchronization signal blocks. Network node.

2. The aforementioned priority information includes condition information representing the conditions for determining the state of the user device. The network node according to claim 1.

3. The aforementioned condition information includes a threshold value for the movement speed of the user device. The network node according to claim 2.

4. The priority information includes priority method information representing a method for prioritizing the second synchronization signal block group over the first synchronization signal block group. The network node according to claim 2.

5. The aforementioned priority method information is, Exclusive information indicating that the second synchronization signal block group selected based on the aforementioned condition information is selected, and the first synchronization signal block group is not selected, Information indicating the priority of the first synchronization signal block group and the second synchronization signal block group, and Offset value of the reception quality value of the synchronization signal block included in the first synchronization signal block group and / or offset value of the reception quality value of the synchronization signal block included in the second synchronization signal block group It is at least one of the following: The network node according to claim 4.

6. The aforementioned beam type is at least one of a wide beam with a beam width greater than or equal to a certain value, and a narrow beam with a beam width less than or equal to a certain value. The network node according to claim 1.

7. The transmitting unit transmits a plurality of different bitmap pieces of information for each frequency according to the beam type, which represent bitmap information indicating whether or not to transmit the synchronization signal block at each transmittable timing of the synchronization signal block within one cycle period. The network node according to claim 1.

8. The bitmap information is ssb-PositionInBurst. The network node according to claim 7.

9. A user device that performs wireless communication with a network node that manages a cell in a mobile communication system, The cell has a receiving unit that receives setting information from the network node for setting each of a plurality of synchronization signal blocks that can be transmitted simultaneously at different frequencies within the bandwidth of the cell as a different synchronization signal block according to the beam type, The receiving unit receives priority information from the network node, which represents information for prioritizing the second synchronization signal block group over the first synchronization signal block group, for a group of synchronization signal blocks consisting of at least one synchronization signal block, and which consists of a first synchronization signal block group and a second synchronization signal block group set as different synchronization signal block groups for each frequency. User device.

10. The priority information includes condition information representing the conditions for determining the state of the user device. The user device according to claim 9.

11. The aforementioned condition information includes a threshold value for the movement speed of the user device. The user device according to claim 10.

12. The priority information includes priority method information representing a method for prioritizing the second synchronization signal block group over the first synchronization signal block group. The user device according to claim 10.

13. The aforementioned priority method information is, Exclusive information indicating that the second synchronization signal block group selected based on the aforementioned condition information is selected, and the first synchronization signal block group is not selected, Information indicating the priority of the first synchronization signal block group and the second synchronization signal block group, and Offset value of the reception quality value of the synchronization signal block included in the first synchronization signal block group and / or offset value of the reception quality value of the synchronization signal block included in the second synchronization signal block group It is at least one of the following: The user device according to claim 12.

14. The aforementioned beam type is at least one of a wide beam with a beam width greater than or equal to a certain value, and a narrow beam with a beam width less than or equal to a certain value. The user device according to claim 9.

15. The receiving unit receives a plurality of bitmap information, each different for each frequency according to the beam type, which indicates whether or not to transmit the synchronization signal block at each transmittable timing of the synchronization signal block within one cycle period. The user device according to claim 9.

16. The bitmap information is ssb-PositionInBurst. The user device according to claim 15.

17. A communication method used in a network node that manages cells in a mobile communication system, Each of the multiple synchronization signal blocks that can be transmitted simultaneously at different frequencies within the bandwidth of the cell is set as a different synchronization signal block according to the beam type, The transmission of setting information representing the aforementioned setting is included, The aforementioned transmission includes transmitting priority information representing information for prioritizing the second synchronization signal block group over the first synchronization signal block group to a first synchronization signal block group and a second synchronization signal block group, which are set as different synchronization signal block groups for each frequency, and which include at least one of the synchronization signal block groups. Communication method.

18. A communication method used in a mobile communication system between a network node that manages a cell and a user device that performs wireless communication, The system includes receiving configuration information from the network node for setting each of a plurality of synchronization signal blocks that can be transmitted simultaneously at different frequencies within the bandwidth of the cell as a different synchronization signal block according to the beam type, The receiving described above includes receiving priority information from the network node, which represents information for prioritizing the second synchronization signal block group over the first synchronization signal block group, with respect to a group of synchronization signal blocks comprising at least one of the synchronization signal blocks, and which is set as a different group of synchronization signal blocks for each frequency. Communication method.