Communication system

Abstract

The communication system comprises: a core network-side device equipped with a position management function of a fifth generation wireless access system; a base station applied to the fifth generation wireless access system; and a repeater that performs relay processing between the base station and a communication terminal, wherein the repeater notifies the core network-side device of at least one of information regarding propagation delay between the connected base station and the own repeater, information regarding the position of the own repeater, and information regarding processing delay at the own repeater, and the communication terminal measures the positioning signal transmitted by the repeater and notifies the core network-side device of the measurement result of the positioning signal. The core network-side device calculates the position of the communication terminal on the basis of the information sent from the repeater and the measurement result sent from the communication terminal.

Description

communication systems

[0001] The present disclosure relates to wireless communication technology.

[0002] The 3GPP (3rd Generation Partnership Project), a standardization organization for mobile communication systems, is studying a fifth-generation (hereinafter sometimes referred to as "5G") wireless access system as a successor to Long Term Evolution (LTE) and Long Term Evolution Advanced (LTE-A), one of the fourth-generation wireless access systems (see Non-Patent Document 1) (for example, Non-Patent Document 2). The technology for the wireless section of 5G is called "New Radio Access Technology" ("New Radio" is abbreviated as "NR"). The NR system is being studied based on the LTE system and the LTE-A system.

[0003] For example, in Europe, an organization called METIS has compiled 5G requirements (see Non-Patent Document 3). The requirements for a 5G wireless access system are that it must have 1000 times the system capacity, 100 times the data transmission speed, one-fifth the data processing delay, and 100 times the number of simultaneous connections of communication terminals compared to an LTE system, while also achieving further reductions in power consumption and cost reductions for the equipment (see Non-Patent Document 3).

[0004] In order to meet such demands, 3GPP is currently studying 5G standards (see Non-Patent Documents 4 to 23).

[0005] The NR access method uses OFDM (Orthogonal Frequency Division Multiplexing) in the downlink direction and OFDM and DFT-s-OFDM (Discrete Fourier Transform-spread-OFDM) in the uplink direction. Also, like LTE and LTE-A, the 5G system does not include circuit switching and is only a packet communication method.

[0006] NR allows the use of higher frequencies than LTE in order to improve transmission speeds and reduce processing delays.

[0007] In NR, which may use higher frequencies than LTE, cell coverage is ensured by forming a narrow beam-shaped transmission and reception range (beam forming) and changing the direction of the beam (beam sweeping).

[0008] The decisions made by 3GPP regarding the frame structure in an NR system, as described in Non-Patent Document 1 (Chapter 5), are explained using Figure 1. Figure 1 is an explanatory diagram showing the structure of a radio frame used in an NR communication system. In Figure 1, one radio frame is 10 ms. The radio frame is divided into 10 equally sized subframes. The NR frame structure supports one or more numerologies, i.e., one or more subcarrier spacings (SCSs). In NR, one subframe is 1 ms long, and one slot consists of 14 symbols, regardless of the subcarrier spacing. Furthermore, the number of slots included in one subframe is one when the subcarrier spacing is 15 kHz, and the number of slots at other subcarrier spacings increases in proportion to the subcarrier spacing (see Non-Patent Document 11 (3GPP TS38.211)).

[0009] 3GPP's decisions regarding channel configuration in NR systems are described in Non-Patent Document 2 (Chapter 5) and Non-Patent Document 11.

[0010] A physical broadcast channel (PBCH) is a channel for downlink transmission from a base station device (hereinafter sometimes simply referred to as a "base station") to a communication terminal device (hereinafter sometimes referred to as a "communication terminal" or "terminal") such as a mobile terminal device (hereinafter sometimes simply referred to as a "mobile terminal"). The PBCH is transmitted together with a downlink synchronization signal.

[0011] Downlink synchronization signals in NR include a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS). Synchronization signals are transmitted from base stations as synchronization signal bursts (hereinafter sometimes referred to as SS bursts) at predetermined intervals and for a predetermined duration. SS bursts are composed of synchronization signal blocks (hereinafter sometimes referred to as SS blocks) for each beam of the base station.

[0012] The base station transmits the SS block of each beam by changing the beam during the duration of the SS burst. The SS block consists of the P-SS, S-SS, and PBCH.

[0013] The Physical Downlink Control Channel (PDCCH) is a channel for downlink transmission from a base station to a communication terminal. The PDCCH carries downlink control information (DCI). The DCI includes resource allocation information for a Downlink Shared Channel (DL-SCH), which is one of the transport channels described below, resource allocation information for a Paging Channel (PCH), which is one of the transport channels described below, and Hybrid Automatic Repeat reQuest (HARQ) information related to the DL-SCH. The DCI may also include an uplink scheduling grant. The DCI may also include an acknowledgement (Ack) / negative acknowledgement (Nack), which is a response signal to the uplink transmission. In addition, in order to flexibly switch between DL and UL within a slot, the DCI may include a slot format indication (SFI). The PDCCH or the DCI is also called an L1 / L2 control signal.

[0014] In NR, a time-frequency region that is a candidate for including a PDCCH is provided. This region is called a control resource set (CORESET). A communication terminal monitors the CORESET and acquires a PDCCH.

[0015] The Physical Downlink Shared Channel (PDSCH) is a channel for downlink transmission from a base station to a communication terminal. The Downlink Shared Channel (DL-SCH), which is a transport channel, and the PCH, which is a transport channel, are mapped to the PDSCH.

[0016] The Physical Uplink Control Channel (PUCCH) is a channel for uplink transmission from a communication terminal to a base station. The PUCCH carries uplink control information (UCI). The UCI includes Ack / Nack, which is a response signal to a downlink transmission, CSI (Channel State Information), a scheduling request (SR), and the like. The CSI is composed of a Rank Indicator (RI), a Precoding Matrix Indicator (PMI), and a CQI (Channel Quality Indicator) report. The RI is rank information of a channel matrix in MIMO (Multiple Input Multiple Output). The PMI is information on a precoding weight matrix used in MIMO. The CQI is quality information indicating the quality of received data or the quality of a communication path. The UCI may be carried by the PUSCH, which will be described later. The PUCCH or UCI is also called an L1 / L2 control signal.

[0017] The Physical Uplink Shared Channel (PUSCH) is a channel for uplink transmission from a communication terminal to a base station. The Uplink Shared Channel (UL-SCH), which is one of the transport channels, is mapped to the PUSCH.

[0018] A physical random access channel (PRACH) is a channel for uplink transmission from a communication terminal to a base station. The PRACH carries a random access preamble.

[0019] A downlink reference signal (RS) is a known symbol in an NR communication system. The following four types of downlink reference signals are defined: a demodulation reference signal (DM-RS), which is a UE-specific reference signal, a phase tracking reference signal (PT-RS), a positioning reference signal (PRS), and a channel state information reference signal (CSI-RS). Measurements of the physical layer of a communication terminal include reference signal received power (RSRP) measurement and reference signal received quality (RSRQ) measurement.

[0020] Similarly, the uplink reference signal is a known symbol in an NR communication system. The following three types of uplink reference signals are defined: a data demodulation reference signal (DM-RS), a phase tracking reference signal (PT-RS), and a sounding reference signal (SRS).

[0021] The transport channels described in Non-Patent Document 2 (Chapter 5) will be described below. Among the downlink transport channels, a broadcast channel (BCH) is broadcast to the entire coverage of the base station (cell). The BCH is mapped to a physical broadcast channel (PBCH).

[0022] Retransmission control using HARQ is applied to the Downlink Shared Channel (DL-SCH). The DL-SCH can be broadcast to the entire coverage of the base station (cell). The DL-SCH supports dynamic or semi-static resource allocation. Semi-static resource allocation is also called semi-persistent scheduling. The DL-SCH supports discontinuous reception (DRX) in communication terminals to reduce power consumption of the communication terminals. The DL-SCH is mapped to the Physical Downlink Shared Channel (PDSCH).

[0023] The Paging Channel (PCH) supports DRX of communication terminals to enable low power consumption of the communication terminals. The PCH is required to broadcast to the entire coverage of the base station (cell). The PCH is mapped to physical resources such as the Physical Downlink Shared Channel (PDSCH) that can be dynamically used for traffic.

[0024] Among the uplink transport channels, the uplink shared channel (UL-SCH) is subject to retransmission control using HARQ. The UL-SCH supports dynamic or semi-static resource allocation. Semi-static resource allocation is also called configured grant. The UL-SCH is mapped to the physical uplink shared channel (PUSCH).

[0025] The Random Access Channel (RACH) is limited to control information, has a risk of collision, and is mapped to the Physical Random Access Channel (PRACH).

[0026] The following describes HARQ. HARQ is a technology that improves the communication quality of a transmission path by combining Automatic Repeat reQuest (ARQ) and Forward Error Correction. HARQ has the advantage that error correction functions effectively through retransmission even for transmission paths whose communication quality varies. In particular, by combining the reception result of the initial transmission and the reception result of the retransmission when retransmitting, it is possible to obtain further quality improvement.

[0027] An example of a retransmission method will be described below. If the receiving side is unable to decode the received data correctly, in other words, if a CRC (Cyclic Redundancy Check) error occurs (CRC=NG), the receiving side will send a "Nack" to the transmitting side. The transmitting side, having received the "Nack", will retransmit the data. If the receiving side is able to decode the received data correctly, in other words, if no CRC error occurs (CRC=OK), the receiving side will send an "Ack" to the transmitting side. The transmitting side, having received the "Ack", will send the next data.

[0028] Another example of a retransmission method will be described. If a CRC error occurs on the receiving side, the receiving side requests a retransmission from the transmitting side. The retransmission request is made by toggling an NDI (New Data Indicator). The transmitting side, upon receiving the retransmission request, retransmits the data. If no CRC error occurs on the receiving side, no retransmission request is made. If the transmitting side does not receive a retransmission request for a predetermined period of time, it assumes that no CRC error occurred on the receiving side.

[0029] The logical channels described in Non-Patent Document 1 (Chapter 6) are explained below. The Broadcast Control Channel (BCCH) is a downlink channel for broadcasting system control information. The BCCH, which is a logical channel, is mapped to the broadcast channel (BCH) or the downlink shared channel (DL-SCH), which are transport channels.

[0030] The Paging Control Channel (PCCH) is a downlink channel for transmitting paging information and changes to system information. The PCCH, which is a logical channel, is mapped to the Paging Channel (PCH), which is a transport channel.

[0031] The Common Control Channel (CCCH) is a channel for transmitting control information between a communication terminal and a base station. The CCCH is used when the communication terminal does not have an RRC connection with the network. In the downlink direction, the CCCH is mapped to the Downlink Shared Channel (DL-SCH), which is a transport channel. In the uplink direction, the CCCH is mapped to the Uplink Shared Channel (UL-SCH), which is a transport channel.

[0032] A Dedicated Control Channel (DCCH) is a channel that transmits dedicated control information between a communication terminal and a network in a one-to-one relationship. The DCCH is used when the communication terminal has an RRC connection with the network. The DCCH is mapped to an uplink shared channel (UL-SCH) in the uplink and to a downlink shared channel (DL-SCH) in the downlink.

[0033] A Dedicated Traffic Channel (DTCH) is a point-to-point communication channel for transmitting user information to a communication terminal. DTCH exists in both uplink and downlink. In uplink, DTCH is mapped to an uplink shared channel (UL-SCH) and in downlink, it is mapped to a downlink shared channel (DL-SCH).

[0034] The location of a communication terminal is tracked in units of an area consisting of one or more cells. Location tracking is performed to track the location of the communication terminal even when it is in standby mode and to call the communication terminal, in other words, to enable the communication terminal to receive calls. The area for tracking the location of this communication terminal is called a Tracking Area (TA).

[0035] In NR, paging of communication terminals within a range that is smaller than a tracking area is supported. This range is called a RAN Notification Area (RNA). Paging of communication terminals in the RRC_INACTIVE state, which will be described later, is performed within this range.

[0036] In NR, in order to support wide frequency bandwidths (transmission bandwidths), carrier aggregation (CA) is being considered, which aggregates (also referred to as "aggregation") two or more component carriers (CCs). CA is described in Non-Patent Document 1.

[0037] When CA is configured, a communication terminal (UE) has only one RRC connection with the network (NW). In the RRC connection, one serving cell provides NAS mobility information and security input. This cell is called a primary cell (PCell). Depending on the UE's capabilities, a secondary cell (SCell) is configured to form a serving cell set together with the PCell. A serving cell set consisting of one PCell and one or more SCells is configured for one UE.

[0038] Furthermore, in 3GPP, in order to further increase communication capacity, there is a dual connectivity (abbreviated as DC) in which a UE connects to two base stations to communicate. DC is described in Non-Patent Documents 1 and 22.

[0039] Of the base stations performing dual connectivity (DC), one may be referred to as a "master base station (Master Node: MN)" and the other as a "secondary base station (Secondary Node: SN)." Serving cells configured by the master base station may be collectively referred to as a master cell group (MCG), and serving cells configured by secondary base stations may be collectively referred to as a secondary cell group (SCG). In DC, the primary cell in the MCG or SCG is referred to as a special cell (SpCell or SPCell). The special cell in the MCG is referred to as a PCell, and the special cell in the SCG is referred to as a primary SCG cell (PSCell).

[0040] In addition, in NR, the base station pre-sets a portion of the carrier frequency band (hereinafter sometimes referred to as the Bandwidth Part (BWP)) for the UE, and the UE transmits and receives data to and from the base station using this BWP, thereby reducing power consumption in the UE.

[0041] Additionally, 3GPP is considering supporting services (or applications) using side link (SL) communication (also referred to as PC5 communication) in both the Evolved Packet System (EPS) (described later) and the 5G core system (see Non-Patent Documents 1, 2, 26 to 28). SL communication involves communication between terminals. Services using SL communication include, for example, vehicle-to-everything (V2X) services and proximity services. In SL communication, not only direct communication between terminals but also communication between a UE and a network via a relay has been proposed (see Non-Patent Documents 26 and 28).

[0042] The physical channels used for SL (see Non-Patent Documents 2 and 11) are as follows: The physical sidelink broadcast channel (PSBCH) carries information related to the system and synchronization and is transmitted from the UE.

[0043] The physical sidelink control channel (PSCCH) carries control information from the UE for sidelink and V2X sidelink communications.

[0044] The physical sidelink shared channel (PSSCH) carries data from the UE for sidelink and V2X sidelink communications.

[0045] The physical sidelink feedback channel (PSFCH) carries HARQ feedback on the sidelink from a UE that received a PSSCH transmission to the UE that transmitted the PSSCH.

[0046] The transport channel used for SL (see Non-Patent Document 1) will be described. The sidelink broadcast channel (SL-BCH) has a predetermined transport format and is mapped to the PSBCH, which is a physical channel.

[0047] The Sidelink Shared Channel (SL-SCH) supports broadcast transmissions. The SL-SCH supports both UE autonomous resource selection and base station scheduled resource allocation. UE autonomous resource selection involves a collision risk, whereas when the UE is allocated dedicated resources by the base station, there is no collision. The SL-SCH also supports dynamic link adaptation by changing transmit power, modulation, and coding. The SL-SCH is mapped to the PSSCH, which is a physical channel.

[0048] The logical channels used for SL (see Non-Patent Document 2) will be described. The Sidelink Broadcast Control Channel (SBCCH) is a sidelink channel for broadcasting sidelink system information from one UE to other UEs. The SBCCH is mapped to the SL-BCH, which is a transport channel.

[0049] The Sidelink Traffic Channel (STCH) is a point-to-multipoint traffic channel for transmitting user information from one UE to other UEs. The STCH is used only by UEs with sidelink communication capability and UEs with V2X sidelink communication capability. Point-to-point communication between two sidelink-capable UEs is also realized by the STCH. The STCH is mapped to the SL-SCH, a transport channel.

[0050] The Sidelink Control Channel (SCCH) is a control channel for transmitting control information from one UE to another UE. The SCCH is mapped to the SL-SCH, which is a transport channel.

[0051] In LTE, only broadcast was supported for SL communication. In NR, support for unicast and groupcast as SL communication in addition to broadcast is being considered (see Non-Patent Document 27 (3GPP TS23.287)).

[0052] In unicast communication and groupcast communication in SL, HARQ feedback (Ack / Nack), CSI reporting, etc. are supported.

[0053] In addition, 3GPP is considering integrated access and backhaul (IAB), which performs both the access link between a UE and a base station and the backhaul link between base stations wirelessly (see Non-Patent Documents 2, 20, and 29).

[0054] 3GPP has proposed several new technologies, such as the introduction of smart repeaters (repeaters capable of beam control) (Non-Patent Document 30). Control methods for smart repeaters from base stations are being studied.

[0055] 3GPP TS36.300 V16.7.03GPP TS38.300 V16.8.0 “Scenarios, requirements and KPIs for 5G mobile and wireless system”, ICT-317669-METIS / D1.13GPP TR23.799 V14.0.03GPP TR38.801 V14.0.03GPP TR38.802 V14.2.03GPP TR38.804 V14.0.03GPP TR38.912 V16.0.03GPP RP-1721153GPP TS23.501 V17.3.03GPP TS38.211 V17.0.03GPP TS38.212 V17.0.03GPP TS38.213 V17.0.03GPP TS38.214 V17.0.03GPP TS38.321 V16.7.03GPP TS38.322 V16.2.03GPP TS38.323 V16.6.03GPP TS37.324 V16.3.03GPP TS38.331 V16.7.03GPP TS38.401 V16.8.03GPP TS38.413 V16.8.03GPP TS37.340 V16.8.03GPP TS38.423 V16.8.03GPP TS38.305 V16.7.03GPP TS23.273 V17.3.03GPP TR23.703 V12.0.03GPP TS23.287 V17.2.03GPP TS23.303 V17.0.03GPP TS38.340 V16.5.03GPP RP-2137003GPP RP-2018313GPP TS38.215 V17.1.03GPP TS38.455 V17.0.03GPP TS37.355 V17.0.0

[0056] In a 5G wireless access system, communications for a wide variety of services are performed. To enable such communications, support for communications using smart repeaters is being considered. Furthermore, in a communication system, UE positioning is also performed using transmission and reception of positioning signals (see Non-Patent Document 24). However, because a UE is connected to a base station via a repeater, there is a problem that the UE's position calculation result derived from the transmission and reception of positioning signals may be inaccurate.

[0057] In view of the above-mentioned problems, one of the objects of the present disclosure is to realize a highly reliable communication system that enables positioning of a UE connected to a base station via a smart repeater.

[0058] The communication system includes a core network side device equipped with a location management function for a fifth-generation wireless access system, a base station applied to the fifth-generation wireless access system, and a repeater that performs relay processing between the base station and a communication terminal. The repeater notifies the core network side device of at least one of information regarding propagation delay between a connected base station and the repeater itself, information regarding the location of the repeater itself, and information regarding processing delay in the repeater itself. The communication terminal measures a positioning signal transmitted by the repeater and notifies the core network side device of the measurement result of the positioning signal. The core network side device calculates the position of the communication terminal based on the information notified from the repeater and the measurement result notified from the communication terminal.

[0059] According to the present disclosure, it is possible to measure the position of a UE connected to a base station via a smart repeater, thereby realizing a highly reliable communication system.

[0060] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings, in which the smart repeater will be simply referred to as a "repeater."

[0061] 1 is an explanatory diagram showing the configuration of a radio frame used in an NR communication system. FIG. 2 is a block diagram showing the overall configuration of an NR communication system 210 being discussed in 3GPP. FIG. 3 is a configuration diagram of DC by a base station connected to an NG core. FIG. 4 is a block diagram showing the configuration of a mobile terminal 202 shown in FIG. 2. FIG. 5 is a block diagram showing the configuration of a base station 213 shown in FIG. 2. FIG. 6 is a block diagram showing the configuration of a 5GC unit. FIG. 7 is a flowchart showing an overview of operations from cell search to standby operation performed by a communication terminal (UE) in an NR communication system. FIG. 8 is a diagram showing an example of the configuration of a cell in an NR system. FIG. 9 is a connection configuration diagram showing an example of the connection configuration of a terminal in SL communication. FIG. 10 is a connection configuration diagram showing an example of the connection configuration of a base station supporting access / backhaul integration. FIG. 11 is a sequence diagram showing an example of a positioning procedure for a UE connecting to a base station via a repeater for a first embodiment. FIG. 12 is a sequence diagram showing another example of a positioning procedure for a UE connecting to a base station via a repeater for a first embodiment. FIG. 13 is a sequence diagram showing another example of a positioning procedure for a UE connecting to a base station via a repeater for a second embodiment. FIG. 14 is a sequence diagram showing another example of a positioning procedure for a UE connecting to a base station via a repeater for a second embodiment. 10 is a diagram showing an example of a protocol stack in a repeater, a base station, an AMF, and an LMF for a third embodiment. FIG. 11 is a diagram showing another example of a protocol stack in a repeater, a base station, an AMF, and an LMF for a third embodiment. FIG. 12 is a sequence diagram showing another example of a positioning procedure for a UE connecting to a base station via a repeater for a third embodiment. FIG. 13 is a sequence diagram showing another example of a positioning procedure for a UE connecting to a base station via a repeater for a third embodiment. FIG. 14 is a sequence diagram showing another example of a positioning procedure for a UE connecting to a base station via a repeater for a third embodiment.

[0062] Embodiment 1. Figure 2 is a block diagram showing the overall configuration of an NR communication system 210 being discussed in 3GPP. Figure 2 will be explained. The radio access network is called an NG-RAN (Next Generation Radio Access Network) 211. A mobile terminal device (hereinafter referred to as a "mobile terminal (User Equipment: UE)") 202, which is a communication terminal device, is capable of wireless communication with a base station device (hereinafter referred to as an "NR base station (NG-RAN NodeB: gNB)") 213, and transmits and receives signals via wireless communication. The NG-RAN 211 is composed of one or more NR base stations 213.

[0063] Here, the term "communication terminal device" includes not only mobile terminal devices such as mobile cell phone terminal devices, but also stationary devices such as sensors. In the following description, the term "communication terminal device" may be simply referred to as a "communication terminal."

[0064] An access stratum (AS) protocol is terminated between the UE 202 and the NG-RAN 211. Examples of AS protocols that are used include radio resource control (RRC), service data adaptation protocol (SDAP), packet data convergence protocol (PDCP), radio link control (RLC), medium access control (MAC), and physical layer (PHY). RRC is used in the control plane (hereinafter sometimes referred to as the C-plane or C-plane), SDAP is used in the user plane (hereinafter sometimes referred to as the U-plane or U-plane), and PDCP, MAC, RLC, and PHY are used in both the C-plane and the U-plane.

[0065] The control protocol RRC (Radio Resource Control) between the UE 202 and the NR base station 213 performs broadcasting, paging, RRC connection management, etc. The states of the NR base station 213 and the UE 202 in RRC include RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE.

[0066] In RRC_IDLE, PLMN (Public Land Mobile Network) selection, system information (SI) broadcast, paging, cell re-selection, mobility, etc. are performed. In RRC_CONNECTED, the mobile terminal has an RRC connection and can transmit and receive data with the network. In addition, in RRC_CONNECTED, handover (HO), measurement of neighbor cells, etc. are performed. In RRC_INACTIVE, the connection between the 5G core unit 214 and the NR base station 213 is maintained, and system information (SI) broadcast, paging, cell re-selection, mobility, etc. are performed.

[0067] The gNB 213 is connected to a 5G core unit (hereinafter sometimes referred to as the "5GC unit") 214, which includes an Access and Mobility Management Function (AMF), a Session Management Function (SMF), or a User Plane Function (UPF), via an NG interface. Control information and / or user data is communicated between the gNB 213 and the 5GC unit 214. The NG interface is a collective term for the N2 interface between the gNB 213 and the AMF 220, the N3 interface between the gNB 213 and the UPF 221, the N11 interface between the AMF 220 and the SMF 222, and the N4 interface between the UPF 221 and the SMF 222. Multiple 5GC units 214 may be connected to one gNB 213. The gNBs 213 are connected via an Xn interface, and control information and / or user data are communicated between the gNBs 213.

[0068] The 5GC unit 214 is a higher-level device, specifically a higher-level node, and controls the connection between the NR base station 213 and the mobile terminal (UE) 202, distributes paging signals to one or more NR base stations (gNB) 213 and / or LTE base stations (E-UTRAN NodeB: eNB), and performs other functions. The 5GC unit 214 also performs mobility control in the idle state. The 5GC unit 214 manages the tracking area list when the mobile terminal 202 is in the idle state, in the inactive state, and in the active state. The 5GC unit 214 initiates a paging protocol by transmitting a paging message to a cell belonging to the tracking area in which the mobile terminal 202 is registered.

[0069] The gNB 213 may configure one or more cells. When one gNB 213 configures multiple cells, each cell is configured to be able to communicate with the UE 202.

[0070] The gNB 213 may be divided into a central unit (hereinafter, sometimes referred to as CU) 215 and a distributed unit (hereinafter, sometimes referred to as DU) 216. One CU 215 is configured within the gNB 213. One or more DUs 216 are configured within the gNB 213. One DU 216 configures one or more cells. The CU 215 is connected to the DU 216 via an F1 interface, and control information and / or user data is communicated between the CU 215 and the DU 216. The F1 interface consists of an F1-C interface and an F1-U interface. The CU 215 is responsible for the functions of the RRC, SDAP, and PDCP protocols, and the DU 216 is responsible for the functions of the RLC, MAC, and PHY protocols. One or more TRPs (Transmission Reception Points) 219 may be connected to the DU 216. The TRP 219 transmits and receives radio signals to and from the UE.

[0071] The CU 215 may be divided into a C-plane CU (CU-C) 217 ​​and a U-plane CU (CU-U) 218. One CU-C 217 is configured within the CU 215. One or more CU-Us 218 are configured within the CU 215. The CU-C 217 is connected to the CU-U 218 via an E1 interface, and control information is communicated between the CU-C 217 and the CU-U 218. The CU-C 217 is connected to the DU 216 via an F1-C interface, and control information is communicated between the CU-C 217 and the DU 216. The CU-U 218 is connected to the DU 216 via an F1-U interface, and user data is communicated between the CU-U 218 and the DU 216.

[0072] In a 5G communication system, a Unified Data Management (UDM) function and a Policy Control Function (PCF) described in Non-Patent Document 10 (3GPP TS23.501) may be included. The UDM and / or PCF may be included in the 5GC unit 214 in FIG. 2 .

[0073] In a 5G communication system, a Location Management Function (LMF) described in Non-Patent Document 24 (3GPP TS 38.305) may be provided. The LMF may be connected to a base station via an AMF as disclosed in Non-Patent Document 25 (3GPP TS 23.273).

[0074] A 5G communication system may include a Non-3GPP Interworking Function (N3IWF) described in Non-Patent Document 10 (3GPP TS23.501). The N3IWF may terminate an Access Network (AN) between the UE and the N3IWF in non-3GPP access between the UE and the N3IWF.

[0075] FIG. 3 is a diagram showing a DC (dual connectivity) configuration connected to an NG core. In FIG. 3, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In FIG. 3, the master base station 240-1 may be a gNB or an eNB. Furthermore, the secondary base station 240-2 may be a gNB or an eNB. For example, in FIG. 3, a DC configuration in which the master base station 240-1 is a gNB and the secondary base station 240-2 is an eNB may be referred to as NG-EN-DC. In FIG. 3, an example is shown in which the U-Plane connection between the 5GC unit 214 and the secondary base station 240-2 is performed via the master base station 240-1, but it may also be performed directly between the 5GC unit 214 and the secondary base station 240-2. 3, an EPC (Evolved Packet Core), which is a core network connected to the LTE system and the LTE-A system, may be connected to the master base station 240-1 instead of the 5GC unit 214. A U-Plane connection may be directly established between the EPC and the secondary base station 240-2.

[0076] FIG. 4 is a block diagram showing the configuration of mobile terminal 202 shown in FIG. 2. The transmission process of mobile terminal 202 shown in FIG. 4 will be described. First, control data from control unit 310 and user data from application unit 302 are sent to protocol processing unit 301. Buffering of the control data and user data may be performed. Buffers for the control data and user data may be provided in control unit 310, application unit 302, or protocol processing unit 301. Protocol processing unit 301 performs protocol processing such as SDAP, PDCP, RLC, and MAC, for example, determining a destination base station in DC, and adding a header for each protocol. The protocol-processed data is passed to encoder unit 304, where it is subjected to encoding such as error correction. Some data may be output directly from protocol processing unit 301 to modulation unit 305 without being encoded. The data encoded by encoder unit 304 is modulated by modulation unit 305. Precoding in MIMO may be performed by modulation unit 305. The modulated data is converted into a baseband signal, and then output to frequency conversion section 306, where it is converted into a radio transmission frequency. Then, the transmission signal is transmitted from antennas 307-1 to 307-4 to base station 213. Although the example in FIG. 4 shows a case where the number of antennas is four, the number of antennas is not limited to four.

[0077] Furthermore, the reception process of the mobile terminal 202 is performed as follows. Radio signals from the base station 213 are received by the antennas 307-1 to 307-4. The received signals are converted from a radio reception frequency to a baseband signal by the frequency conversion unit 306, and demodulated by the demodulation unit 308. The demodulation unit 308 may also perform weight calculation and multiplication processing. The demodulated data is passed to the decoder unit 309, where decoding processes such as error correction are performed. The decoded data is passed to the protocol processing unit 301, where protocol processing such as MAC, RLC, PDCP, and SDAP is performed, for example, operations such as removing headers in each protocol. Of the data that has undergone protocol processing, the control data is passed to the control unit 310, and the user data is passed to the application unit 302.

[0078] A series of processes in the mobile terminal 202 is controlled by a control unit 310. Therefore, the control unit 310 is also connected to each of the units 302, 304 to 309, although this is omitted in FIG.

[0079] Each unit of the mobile terminal 202, such as the control unit 310, protocol processing unit 301, encoder unit 304, and decoder unit 309, is implemented by a processing circuit including, for example, a processor and memory. For example, the control unit 310 is implemented by a processor executing a program describing a series of processes performed by the mobile terminal 202. The program describing the series of processes performed by the mobile terminal 202 is stored in memory. Examples of memory include non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), and flash memory. Each unit of the mobile terminal 202, such as the control unit 310, protocol processing unit 301, encoder unit 304, and decoder unit 309, may be implemented by a dedicated processing circuit such as an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or a DSP (Digital Signal Processor). In FIG. 4, the number of antennas used by the mobile terminal 202 for transmission and the number of antennas used for reception may be the same or different.

[0080] 5 is a block diagram showing the configuration of the base station 213 shown in FIG. 2. The transmission process of the base station 213 shown in FIG. 5 will be described. The EPC communication unit 401 transmits and receives data between the base station 213 and the EPC. The 5GC communication unit 412 transmits and receives data between the base station 213 and the 5GC (such as the 5GC unit 214). The other base station communication unit 402 transmits and receives data with other base stations. The EPC communication unit 401, the 5GC communication unit 412, and the other base station communication unit 402 each exchange information with the protocol processing unit 403. Control data from the control unit 411, and user data and control data from the EPC communication unit 401, the 5GC communication unit 412, and the other base station communication unit 402 are sent to the protocol processing unit 403. Buffering of the control data and user data may be performed. Buffers for control data and user data may be provided in the control unit 411, the EPC communication unit 401, the 5GC communication unit 412, or the other base station communication unit 402.

[0081] The protocol processing unit 403 performs protocol processing such as SDAP, PDCP, RLC, MAC, etc., such as routing transmission data in DC, etc., and adding headers for each protocol. The protocol-processed data is passed to the encoder unit 405, where it is subjected to encoding processing such as error correction. Some data may be output directly from the protocol processing unit 403 to the modulation unit 406 without being encoded. Data may also be sent from the protocol processing unit 403 to the other base station communication unit 402. For example, in DC, data sent from the 5GC communication unit 412 or the EPC communication unit 401 may be sent to another base station, such as a secondary base station, via the other base station communication unit 402. The encoded data is modulated by the modulation unit 406. The modulation unit 406 may also perform MIMO precoding. The modulated data is converted into a baseband signal, and then output to the frequency conversion unit 407, where it is converted into a radio transmission frequency. Thereafter, the transmission signals are transmitted from antennas 408-1 to 408-4 to one or more mobile terminals 202. Although the number of antennas is four in the example shown in Fig. 5, the number of antennas is not limited to four.

[0082] Furthermore, the reception process of the base station 213 is performed as follows. Radio signals from one or more mobile terminals 202 are received by antennas 408-1 to 408-4. The received signals are converted from a radio reception frequency to a baseband signal by a frequency conversion unit 407, and demodulated by a demodulation unit 409. The demodulated data is passed to a decoder unit 410, where decoding processes such as error correction are performed. The decoded data is passed to a protocol processing unit 403, where protocol processes such as MAC, RLC, PDCP, and SDAP are performed, for example, operations such as removing headers in each protocol. Of the data that has undergone protocol processing, control data is passed to the control unit 411, 5GC communication unit 412, EPC communication unit 401, or other base station communication unit 402, and user data is passed to the 5GC communication unit 412, EPC communication unit 401, or other base station communication unit 402. Data sent from the other base station communication unit 402 may be sent to the 5GC communication unit 412 or the EPC communication unit 401. The data may be, for example, uplink data sent to the 5GC communication unit 412 or the EPC communication unit 401 via another base station in DC.

[0083] A series of processes in the base station 213 is controlled by a control unit 411. Therefore, the control unit 411 is also connected to each of the units 401, 402, 405 to 410, and 412, although this is omitted in FIG.

[0084] Each unit of the base station 213, for example, the control unit 411, the protocol processing unit 403, the 5GC communication unit 412, the EPC communication unit 401, the other base station communication unit 402, the encoder unit 405, and the decoder unit 410, is realized by a processing circuit including a processor and a memory, or a dedicated processing circuit such as an FPGA, an ASIC, or a DSP, similar to the above-mentioned mobile terminal 202. In Fig. 5, the number of antennas used by the base station 213 for transmission and the number of antennas used for reception may be the same or different.

[0085] As an example of the configuration of the CU 215 shown in Fig. 2, a configuration in which a DU communication unit is provided is sometimes used, excluding the encoder unit 405, modulation unit 406, frequency conversion unit 407, antennas 408-1 to 408-4, demodulation unit 409, and decoder unit 410 shown in Fig. 5. The DU communication unit is connected to a protocol processing unit 403. The protocol processing unit 403 in the CU 215 performs protocol processing such as PDCP and SDAP.

[0086] As an example of the configuration of the DU 216 shown in Fig. 2, a configuration in which a CU communication unit is provided may be used, excluding the EPC communication unit 401, other base station communication unit 402, and 5GC communication unit 412 shown in Fig. 5. The CU communication unit is connected to a protocol processing unit 403. The protocol processing unit 403 in the DU 216 performs protocol processing such as PHY, MAC, and RLC.

[0087] FIG. 6 is a block diagram showing the configuration of the 5GC unit. FIG. 6 shows the configuration of the 5GC unit 214 shown in FIG. 2 described above. FIG. 6 shows a case where the 5GC unit 214 shown in FIG. 2 includes an AMF configuration, an SMF configuration, and a UPF configuration. In the example shown in FIG. 6, the AMF may have the function of the control plane control unit 525, the SMF may have the function of the session management unit 527, and the UPF may have the functions of the user plane communication unit 523 and the Data Network communication unit 521. The Data Network communication unit 521 transmits and receives data between the 5GC unit 214 and the Data Network. The base station communication unit 522 transmits and receives data via the NG interface between the 5GC unit 214 and the base station 213. User data sent from the Data Network is passed from the Data Network communication unit 521 to the base station communication unit 522 via the user plane communication unit 523, and then transmitted to one or more base stations 213. User data sent from the base station 213 is passed from the base station communication unit 522 to the Data Network communication unit 521 via the user plane communication unit 523, and then transmitted to the Data Network.

[0088] The control data sent from the base station 213 is passed from the base station communication unit 522 to the control plane control unit 525. The control plane control unit 525 may pass the control data to the session management unit 527. The control data may be sent from the Data Network. The control data sent from the Data Network may be sent from the Data Network communication unit 521 to the session management unit 527 via the user plane communication unit 523. The session management unit 527 may send the control data to the control plane control unit 525.

[0089] The user plane control unit 523 includes a PDU processing unit 523-1, a mobility anchoring unit 523-2, etc., and performs general processing for the user plane (hereinafter sometimes referred to as U-Plane). The PDU processing unit 523-1 processes data packets, for example, transmitting and receiving packets to and from the Data Network communication unit 521, and transmitting and receiving packets to and from the base station communication unit 522. The mobility anchoring unit 523-2 is responsible for anchoring the data path during UE mobility.

[0090] The session management unit 527 manages the PDU session established between the UE and the UPF. The session management unit 527 includes a PDU session control unit 527-1, a UE IP address allocation unit 527-2, etc. The PDU session control unit 527-1 manages the PDU session between the mobile terminal 202 and the 5GC unit 214. The UE IP address allocation unit 527-2 assigns an IP address to the mobile terminal 202, etc.

[0091] The control plane control unit 525 includes a NAS security unit 525-1, an idle state mobility management unit 525-2, etc., and performs overall processing for the control plane (hereinafter sometimes referred to as the C-Plane). The NAS security unit 525-1 performs security for NAS (Non-Access Stratum) messages, etc. The idle state mobility management unit 525-2 performs mobility management in the standby state (idle state: also referred to as RRC_IDLE state or simply idle), generation and control of paging signals in the standby state, addition, deletion, update, search, tracking area list management, etc. for one or more mobile terminals 202 under its control.

[0092] A series of processes of the 5GC unit 214 is controlled by a control unit 526. Therefore, although the control unit 526 is omitted in Fig. 6, it is connected to each unit 521 to 523, 525, and 527. Like the control unit 310 of the mobile terminal 202 described above, each unit of the 5GC unit 214 is realized by, for example, a processing circuit configured to include a processor and memory, or a dedicated processing circuit such as an FPGA, ASIC, or DSP.

[0093] Next, an example of a cell search method in a communication system is shown. Fig. 7 is a flowchart showing an outline of the process from cell search to standby operation performed by a communication terminal (UE) in an NR communication system. When the communication terminal starts a cell search, in step ST601, it synchronizes slot timing and frame timing using a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS) transmitted from a surrounding base station.

[0094] P-SS and S-SS are collectively called a synchronization signal (SS). A synchronization code is assigned to the synchronization signal (SS) in one-to-one correspondence with a PCI (Physical Cell Identifier) ​​assigned to each cell. 1008 different PCIs are being considered. A communication terminal synchronizes using these 1008 different PCIs and detects (identifies) the PCI of the synchronized cell.

[0095] In step ST602, the communication terminal receives the PBCH for the next synchronized cell. A master information block (MIB) including cell configuration information is mapped to the BCCH on the PBCH. Therefore, the MIB can be obtained by receiving the PBCH and obtaining the BCCH. Examples of MIB information include a system frame number (SFN), scheduling information for system information block (SIB) 1, subcarrier spacing for SIB1 and the like, and information on the DM-RS position.

[0096] Furthermore, the communication terminal acquires an SS block identifier from the PBCH. A part of the bit string of the SS block identifier is included in the MIB. The remaining bit string is included in an identifier used to generate a sequence of DM-RS associated with the PBCH. The communication terminal acquires the SS block identifier using the MIB included in the PBCH and the sequence of DM-RS associated with the PBCH.

[0097] Next, in step ST603, the communication terminal measures the received power of the SS block.

[0098] Next, in step ST604, the communication terminal selects the cell with the best reception quality, for example, the cell with the highest reception power, that is, the best cell, from among the one or more cells detected up to step ST603. The communication terminal also selects the beam with the best reception quality, for example, the beam with the highest reception power of the SS block, that is, the best beam. The reception power of the SS block for each SS block identifier is used, for example, to select the best beam.

[0099] Next, in step ST605, the communication terminal receives DL-SCH based on the scheduling information of SIB1 included in the MIB, and obtains SIB (System Information Block) 1 in the broadcast information BCCH. SIB1 includes information on access to the cell, cell configuration information, and scheduling information of other SIBs (SIBk: k is an integer greater than or equal to 2). SIB1 also includes a tracking area code (TAC).

[0100] Next, in step ST606, the communication terminal compares the TAC of SIB1 received in step ST605 with the TAC portion of the tracking area identity (TAI) in the tracking area list already held by the communication terminal. The tracking area list is also called a TAI list. The TAI is identification information for identifying a tracking area, and is composed of an MCC (Mobile Country Code), an MNC (Mobile Network Code), and a TAC (Tracking Area Code). The MCC is a country code. The MNC is a network code. The TAC is a tracking area code number.

[0101] If the comparison in step ST606 shows that the TAC received in step ST605 is the same as the TAC included in the tracking area list, the communication terminal enters standby mode in the cell. If the comparison shows that the TAC received in step ST605 is not included in the tracking area list, the communication terminal requests a core network (EPC) including an MME and the like to change the tracking area through the cell in order to perform a Tracking Area Update (TAU).

[0102] An apparatus constituting a core network (hereinafter sometimes referred to as a "core network side apparatus") updates the tracking area list based on the identification number (UE-ID, etc.) of the communication terminal sent from the communication terminal together with a TAU request signal. The core network side apparatus transmits the updated tracking area list to the communication terminal. The communication terminal rewrites (updates) the TAC list held by the communication terminal based on the received tracking area list. Thereafter, the communication terminal enters standby mode in the cell.

[0103] Next, examples of random access methods in a communication system are shown. Four-step random access and two-step random access are used for random access. For each of the four-step and two-step random access methods, there is contention-based random access, i.e., random access in which timing collisions with other mobile terminals may occur, and contention-free random access.

[0104] An example of a collision-based four-step random access method is shown below. In the first step, the mobile terminal transmits a random access preamble to the base station. The random access preamble may be selected by the mobile terminal from a predetermined range, or may be individually assigned to the mobile terminal and notified by the base station.

[0105] In the second step, the base station transmits a random access response to the mobile terminal, which includes uplink scheduling information used in the third step, a terminal identifier used in the uplink transmission in the third step, and the like.

[0106] In the third step, the mobile terminal performs uplink transmission to the base station. The mobile terminal uses the information acquired in the second step for uplink transmission. In the fourth step, the base station notifies the mobile terminal whether or not the collision has been resolved. If the mobile terminal is notified that there is no collision, it ends the random access process. If the mobile terminal is notified that there is a collision, it starts the process over from the first step.

[0107] The contention-free four-step random access method differs from the contention-based four-step random access method in the following points: Prior to the first step, the base station pre-assigns a random access preamble and uplink scheduling to the mobile terminal, and the notification of whether or not contention has been resolved in the fourth step is not required.

[0108] An example of a collision-based two-step random access method is shown below. In the first step, the mobile terminal transmits a random access preamble and performs uplink transmission to the base station. In the second step, the base station notifies the mobile terminal whether there is a collision. If the mobile terminal is notified that there is no collision, it terminates the random access process. If the mobile terminal is notified that there is a collision, it restarts the process from the first step.

[0109] The contention-free two-step random access method differs from the contention-based two-step random access method in the following points: prior to the first step, the base station pre-assigns a random access preamble and uplink scheduling to the mobile terminal, and in the second step, the base station transmits a random access response to the mobile terminal.

[0110] FIG. 8 shows an example of a cell configuration in NR. In an NR cell, narrow beams are formed and transmitted in different directions. In the example shown in FIG. 8, at certain times, base station 750 transmits and receives signals to and from a mobile terminal using beam 751-1. At other times, base station 750 transmits and receives signals to and from a mobile terminal using beam 751-2. In a similar manner, base station 750 transmits and receives signals to and from a mobile terminal using one or more of beams 751-3 to 751-8. In this way, base station 750 forms a wide-area cell 752.

[0111] 8 shows an example in which the number of beams used by the base station 750 is 8, but the number of beams may be different from 8. Also, in the example shown in FIG. 8, the number of beams used simultaneously by the base station 750 is 1, but it may be multiple.

[0112] The concept of Quasi-CoLocation (QCL) is used to identify beams (see Non-Patent Document 14 (3GPP TS38.214)). That is, the beam is identified by information indicating which reference signal (e.g., SS block, CSI-RS) the beam can be considered to be the same as. The information may include types of information regarding the aspects of the beams that can be considered to be the same, such as Doppler shift, Doppler shift spread, mean delay, mean delay spread, and spatial Rx parameters (see Non-Patent Document 14 (3GPP TS38.214)).

[0113] In 3GPP, a side link (SL) is supported for D2D (Device to Device) communication and V2V (Vehicle to Vehicle) communication (see Non-Patent Document 1 and Non-Patent Document 16). The SL is defined by the PC5 interface.

[0114] In order to support unicast and groupcast in addition to broadcast in SL communication, support for PC5-S signaling is being considered (see Non-Patent Document 27 (3GPP TS23.287)). For example, PC5-S signaling is implemented to establish a link for implementing SL, i.e., PC5 communication. The link is implemented in the V2X layer and is also called a Layer 2 link.

[0115] Furthermore, support for RRC signaling in SL communication is being considered (see Non-Patent Document 27 (3GPP TS23.287)). RRC signaling in SL communication is also referred to as PC5 RRC signaling. For example, it has been proposed to notify UE capabilities between UEs performing PC5 communication, or to notify AS layer settings for performing V2X communication using PC5 communication.

[0116] An example of a connection configuration of mobile terminals in SL communication is shown in Fig. 9. In the example shown in Fig. 9, UE 805 and UE 806 exist within the coverage 803 of base station 801. UL / DL communication 807 is performed between base station 801 and UE 805. UL / DL communication 808 is performed between base station 801 and UE 806. SL communication 810 is performed between UE 805 and UE 806. UE 811 and UE 812 exist outside the coverage 803. SL communication 814 is performed between UE 805 and UE 811. In addition, SL communication 816 is performed between UE 811 and UE 812.

[0117] As an example of communication between a UE and a NW via a relay in SL communication, a UE 805 shown in FIG. 9 relays communication between a UE 811 and a base station 801.

[0118] A configuration similar to that shown in FIG. 4 may be used for a UE that performs relaying. The relaying process in the UE will be described using FIG. 4. The relaying process by UE 805 in communication from UE 811 to base station 801 will be described. A radio signal from UE 811 is received by antennas 307-1 to 307-4. The received signal is converted from a radio reception frequency to a baseband signal by frequency conversion unit 306, and demodulated by demodulation unit 308. Weight calculation and multiplication processing may also be performed by demodulation unit 308. The demodulated data is passed to decoder unit 309, where decoding processing such as error correction is performed. The decoded data is passed to protocol processing unit 301, where protocol processing such as MAC and RLC used for communication with UE 811 is performed, such as removing headers in each protocol. Protocol processing such as RLC and MAC used for communication with base station 801 is also performed, such as adding headers in each protocol. Protocol processing of PDCP and SDAP may be performed in protocol processing unit 301 of UE 811. The protocol-processed data is passed to encoder unit 304, where encoding such as error correction is performed. Some data may be output directly from protocol processing unit 301 to modulation unit 305 without being encoded. The data encoded by encoder unit 304 is modulated by modulation unit 305. Precoding in MIMO may be performed by modulation unit 305. The modulated data is converted into a baseband signal, and then output to frequency conversion unit 306, where it is converted into a radio transmission frequency. Thereafter, a transmission signal is transmitted to base station 801 from antennas 307-1 to 307-4.

[0119] In the above, an example of relaying by UE 805 in communication from UE 811 to base station 801 has been shown, but similar processing is also used in relaying communication from base station 801 to UE 811.

[0120] 5G base stations can support integrated access and backhaul (IAB) (see Non-Patent Documents 2 and 20). A base station supporting IAB (hereinafter sometimes referred to as an IAB base station) is composed of an IAB donor CU, which is a CU of the base station operating as an IAB donor that provides IAB functions, an IAB donor DU, which is a DU of the base station operating as an IAB donor, and an IAB node connected to the IAB donor DU and to a UE via a radio interface. An F1 interface is provided between the IAB node and the IAB donor CU (see Non-Patent Document 2).

[0121] An example of IAB base station connections is shown in Figure 10. IAB donor CU 901 is connected to IAB donor DU 902. IAB node 903 is connected to IAB donor DU 902 using a wireless interface. IAB node 903 is connected to IAB node 904 using a wireless interface. In other words, IAB nodes may be connected in cascade. UE 905 is connected to IAB node 904 using a wireless interface. UE 906 may be connected to IAB node 903 using a wireless interface, and UE 907 may be connected to IAB donor DU 902 using a wireless interface. Multiple IAB donor DUs 902 may be connected to an IAB donor CU 901, multiple IAB nodes 903 may be connected to an IAB donor DU 902, and multiple IAB nodes 904 may be connected to an IAB node 903.

[0122] A BAP (Backhaul Adaptation Protocol) layer is provided in the connection between the IAB donor DU and the IAB node and in the connection between the IAB nodes (see Non-Patent Document 29). The BAP layer performs operations such as routing received data to the IAB donor DU and / or the IAB node, and mapping to an RLC channel (see Non-Patent Document 29).

[0123] As an example of the configuration of the IAB donor CU, a configuration similar to that of CU 215 is used.

[0124] An example of the configuration of the IAB donor DU is the same as that of the DU 216. The protocol processing unit of the IAB donor DU performs BAP layer processing, such as adding a BAP header to downstream data, routing to an IAB node, and removing the BAP header from upstream data.

[0125] As an example of the configuration of an IAB node, a configuration excluding the EPC communication unit 401, other base station communication unit 402, and 5GC communication unit 412 shown in Figure 5 may be used.

[0126] The transmission and reception processing at the IAB node will be described using FIGS. 5 and 10 . The transmission and reception processing at the IAB node 903 in communication between the IAB donor CU 901 and the UE 905 will be described. In uplink communication from the UE 905 to the IAB donor CU 901, a radio signal from the IAB node 904 is received by the antenna 408 (some or all of the antennas 408-1 to 408-4). The received signal is converted from a radio reception frequency to a baseband signal by the frequency conversion unit 407, and demodulated by the demodulation unit 409. The demodulated data is passed to the decoder unit 410, where decoding processing such as error correction is performed. The decoded data is passed to the protocol processing unit 403, where protocol processing such as MAC and RLC used for communication with the IAB node 904 is performed, such as removing headers in each protocol. In addition, routing to the IAB donor DU 902 is performed using a BAP header, and protocol processing such as RLC and MAC used for communication with the IAB donor DU 902, such as adding headers for each protocol, is performed. The protocol-processed data is passed to the encoder unit 405, where it is subjected to encoding processing such as error correction. Some data may be output directly from the protocol processing unit 403 to the modulation unit 406 without being encoded. The encoded data is modulated by the modulation unit 406. The modulation unit 406 may also perform precoding in MIMO. The modulated data is converted into a baseband signal, and then output to the frequency conversion unit 407, where it is converted into a radio transmission frequency. Then, a transmission signal is transmitted to the IAB donor DU 902 from antennas 408-1 to 408-4. Similar processing is performed in downlink communication from the IAB donor CU 901 to the UE 905.

[0127] The IAB node 904 also performs the same transmission and reception processing as the IAB node 903. The protocol processing unit 403 of the IAB node 903 performs BAP layer processing, such as adding a BAP header and routing to the IAB node 904 in upstream communication, and removing the BAP header in downstream communication.

[0128] A repeater may be used for communication between a base station and a UE (hereinafter, sometimes referred to as an access link (AL) (see Non-Patent Document 31)). The repeater may have multiple beams. The repeater may receive a signal from a source, amplify it, and transmit the amplified signal to a destination (this operation may be referred to as AL transmission / reception). The repeater may use beams for AL transmission / reception.

[0129] The base station may control the repeater. The base station may transmit a control signal to the repeater (the link used for transmitting the control signal from the base station to the repeater is sometimes called a fronthaul link (FL) (see Non-Patent Document 31)). L1 / L2 signaling may be used for the control signal.

[0130] The base station may control the beam used by the repeater. The control by the base station may be, for example, switching of the beam. The base station may switch the beam, for example, when the UE moves.

[0131] Positioning of a UE connected to a base station via a repeater may be performed. For example, the UE may receive a positioning signal transmitted by the base station. The positioning signal may be, for example, a PRS. The UE may notify the LMF of the reception result of the positioning signal. The reception result of the positioning signal may include, for example, information regarding the difference between the reception time of the positioning signal from the base station and the reception time of a positioning signal from another base station. The LMF may use the information to calculate the position of the UE.

[0132] However, because the UE is connected to the base station via a repeater, the difference between the time the UE receives the positioning signal and the time the base station transmits the positioning signal cannot be directly correlated to the distance between the base station and the UE, resulting in an inaccurate position calculation result for the UE.

[0133] In the first embodiment, a method for solving such a problem will be disclosed.

[0134] In this method, the base station notifies the LMF of information about the repeater.

[0135] The information may include, for example, information about a delay time in the repeater, which may be, for example, the time it takes for the repeater to receive and transmit a signal.

[0136] The base station may specify the delay time in the repeater in advance. The base station may notify the repeater of the specified delay time. The repeater may transmit the positioning signal to the UE when the specified time has elapsed after receiving the positioning signal from the base station. This may reduce the amount of processing performed by the repeater in deriving the delay time, for example.

[0137] The information about the repeater notified from the base station to the LMF may include information about the propagation delay from the base station to the repeater, information about the repeater's location, or both of the above information. The information about the repeater's location may be information about the repeater's location itself, information about the relative location between the base station and the repeater, information about the distance between the base station and the repeater, or a combination of the above information. The LMF may use this information to derive the propagation delay between the base station and the LMF. This makes it possible to improve the accuracy of UE location calculation, for example, regardless of the relative positions of the base station, the repeater, and the UE.

[0138] For example, NRPPa signaling (see non-patent document 33 (3GPP TS38.455)) may be used for the notification from the base station to the LMF. For example, signaling of an OTDOA (Observed Time Difference Of Arrival) information response (OTDOA INFORMATION RESPONSE) may be used, signaling of a positioning information response (POSITIONING INFORMATION RESPONSE) may be used, signaling of a positioning information update (POSITIONING INFORMATION UPDATE) may be used, signaling of a TRP information response (TRP INFORMATION RESPONSE) may be used, signaling of a positioning activation response (POSITIONING ACTIVATION RESPONSE) may be used, signaling of a PRS CONFIGURATION RESPONSE may be used, signaling of a measurement preconfiguration confirmation (MEASUREMENT PRECONFIGURATION CONFIRM) may be used, or signaling of assistance information feedback (ASSISTANCE INFORMATION FEEDBACK) may be used. This makes it possible to avoid complexity in the communication system, for example. New NRPPa signaling may be provided. New NRPPa signaling may be used for the notification from the base station to the LMF.

[0139] The LMF may request information about repeaters from the base station. The request may be made using NRPPa signaling. For example, the signaling may be an OTDOA information request (OTDOA INFORMATION REQUEST), a positioning information request (POSITIONING INFORMATION REQUEST), a TRP information request (TRP INFORMATION REQUEST), a positioning activation request (POSITIONING ACTIVATION REQUEST), a PRS configuration request (PRS CONFIGURATION REQUEST), a measurement preconfiguration required (MEASUREMENT PRECONFIGURATION REQUIRED), or an assistance information control (ASSISTANCE INFORMATION CONTROL). This may, for example, reduce complexity in the communication system. A new NRPPa signaling may be provided. The new NRPPa signaling may be used for the request from the LMF to the base station. The request may trigger notification of the information about the repeater from the base station to the LMF.

[0140] The repeater may notify the base station of the information in the repeater itself. For example, Msg3 in the four-step random access process, MsgA in the two-step random access process, or other signaling such as RRC Setup Complete (see Non-Patent Document 19 (3GPP TS 38.331)) may be used for the notification. As another example, the information may be included in capabilities (e.g., UE capabilities) and notified.

[0141] The notification of the information from the repeater to the base station may be triggered by a request from the base station. The base station may request information about the repeater from the repeater in advance. The request from the base station to the repeater may use, for example, Msg2 in the four-step random access process, or other signaling, for example, signaling of an RRC start-up request (see Non-Patent Document 19 (3GPP TS38.331)). As another example, the request may be notified by being included in a capability (e.g., UE capability) request. The request from the base station to the repeater may be triggered by the above-mentioned request from the LMF to the base station.

[0142] The base station may notify the repeater of configurations related to the positioning signal. The configurations may include information about the time / frequency resources of the positioning signal, information about the code sequence of the positioning signal, information about the amplification factor of the repeater, information about the transmit power of the repeater, information about the timing of the transmission of the signal from the repeater, and information about beamforming of the repeater. This allows the repeater to, for example, identify the positioning signal transmitted from the base station, thereby enabling the repeater to appropriately control the positioning signal, for example, receive the signal from the base station and transmit it to the UE. The repeater may also obtain the aforementioned information about the processing delay in the repeater, for example, information about the time it takes for the repeater to receive and transmit the signal.

[0143] The setting may include information about the QCL of the positioning signal. The information may also include information indicating which reference signal (e.g., SS block, CSI-RS) beam the positioning signal is considered to be the same as. The repeater may obtain information about the beam to be used to transmit the positioning signal from the information. This may, for example, reduce the size of information about the setting of the positioning signal.

[0144] The LMF may inquire of the base station whether a repeater is used. The inquiry may include information for identifying the repeater, such as a repeater identifier, or information about the UE that communicates with the base station via the repeater. The inquiry from the LMF to the base station may use NRPPa signaling, such as NRPPa TRP INFORMATION REQUEST signaling. A new NRPPa signaling may be provided. The new NRPPa signaling may be used for the inquiry from the LMF to the base station.

[0145] The base station may notify the LMF of information regarding whether a repeater is used. The information may include information for identifying the repeater, such as a repeater identifier, or information regarding a UE that communicates with the base station via the repeater. The notification of the information may be triggered by the above-mentioned inquiry from the LMF to the base station. The notification from the base station to the LMF may use NRPPa signaling, for example, NRPPa TRP INFORMATION RESPONSE signaling. A new NRPPa signaling may be provided. The new NRPPa signaling may be used for the notification from the base station to the LMF.

[0146] The UE may receive the positioning signal transmitted via the repeater. The UE may notify the LMF of the reception result of the positioning signal. For example, LPP signaling (see Non-Patent Document 34 (3GPP TS37.355)) may be used for the notification. The LMF may use the information to calculate the location of the UE. The LMF may use the above-mentioned information about the repeater notified by the base station. This allows, for example, the LMF to accurately calculate the location of the UE.

[0147] Fig. 11 is a sequence diagram showing an example of a positioning procedure for a UE connecting to a base station via a repeater. In the example shown in Fig. 11, OTDOA positioning is performed. In Fig. 11, a base station transmits a positioning signal. In Fig. 11, an example of positioning related to a location information request (Mobile-Originated Location Request: MO-LR) from a UE is shown. In Fig. 11, an example of UE-assisted positioning (UE-assisted positioning: positioning in which an LMF or the like calculates the position using assistance information from the UE (e.g., a positioning signal reception result)) is shown.

[0148] In Fig. 11, signal transmission and reception between the UE and the base station, AMF, and LMF is performed via a repeater. Also, in Fig. 11, the side control information transmitted from the base station to the repeater is omitted, but by transmitting this side control information prior to signal transmission and reception between the UE and the base station, AMF, and LMF, the base station instructs the repeater to set a beam. The same applies to Fig. 11 and subsequent figures.

[0149] In procedure 2301 shown in FIG. 11, a positioning request from the UE and a positioning capability request and notification between the LMF and the UE are made.

[0150] In steps ST2303 and ST2305 shown in FIG. 11 , the UE requests positioning to the LMF. The request is made via the AMF. Step ST2303 shows the request from the UE to the AMF, and step ST2305 shows the request from the AMF to the LMF.

[0151] In Step ST2307 shown in FIG. 11 , the LMF requests the UE for positioning capability. The request is made using LPP signaling, for example, an LPP capability request. In Step ST2309, the UE notifies the LMF of its positioning capability. The notification is made using LPP signaling, for example, an LPP capability provide request.

[0152] In procedure 2310 shown in Fig. 11, assistance data is requested and notified between the LMF and the UE. In Step ST2311, the LMF requests assistance data from the UE. The request is made using LPP signaling, for example, LPP assistance data request signaling. In Step ST2313, the UE notifies the LMF of the assistance data. The notification is made using LPP signaling, for example, LPP assistance data provision signaling.

[0153] In step ST2315 shown in FIG. 11 , the LMF requests information on whether a repeater is used from the base station. The request may use NRPPa signaling, for example, NRPPa TRP information request signaling. The request may include a request for information on the TRP of the base station. The request for information on whether a repeater is used may include information for identifying the repeater, for example, a request for a repeater identifier, or may include a request for information on UEs that communicate with the base station via the repeater.

[0154] In step ST2317 shown in FIG. 11, the base station notifies the LMF of information regarding whether or not a repeater is used. For this notification, NRPPa signaling, for example, NRPPa TRP information response signaling, may be used. The notification may include information regarding the TRP. In the example shown in FIG. 11, information indicating that a repeater is used is notified.

[0155] In step ST2319 shown in FIG. 11 , the LMF requests information necessary for OTDOA from the base station. The request may use NRPPa signaling, for example, signaling for an NRPPa OTDOA information request. The request may include a request for information about repeaters. The information may include information regarding an instruction to start transmitting a positioning signal. The base station may transmit a positioning signal, for example, a PRS, triggered by step ST2319.

[0156] In step ST2322 shown in FIG. 11 , the base station requests information about the repeater from the repeater. The request may be made, for example, by using L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of the above. In step ST2325, the repeater notifies the base station of information about its own repeater. The notification may be made, for example, by using L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of the above.

[0157] In step ST2327 shown in FIG. 11 , the base station notifies the LMF of information necessary for OTDOA. For this notification, NRPPa signaling, for example, NRPPa OTDOA information response signaling, may be used. The notification may include information about the repeater. The information about the repeater may include, for example, information about the propagation delay from the base station to the repeater, information about the location of the repeater, or information about the processing delay in the repeater.

[0158] In step ST2329 shown in FIG. 11 , the LMF instructs the UE to receive a positioning signal. The instruction may be performed using LPP signaling, for example, signaling of an LPP request location information. The instruction may include information about the positioning signal to be received. The UE starts receiving the positioning signal in response to the instruction.

[0159] In step ST2330 shown in FIG. 11 , a positioning signal is transmitted from the base station to the UE. This transmission is performed via a repeater. The repeater receives the positioning signal from the base station and transmits the signal to the UE. In step ST2331, the UE measures the positioning signal transmitted from the base station via the repeater.

[0160] In step ST2333 shown in FIG. 11 , the UE reports the measurement result of the positioning signal to the LMF. The report may be made using LPP signaling, for example, LPP Provide Location Information signaling. The report may include information on the difference between the reception time of the positioning signal received from the base station via a repeater and the reception time of the positioning signal received from another base station, or may include information on the other base station. The positioning signal received by the UE from another base station may be a positioning signal received directly from the other base station, or may be a positioning signal received via a repeater connected to the base station. The UE may not be aware of whether the received positioning signal is received directly from the base station or via a repeater.

[0161] In procedure 2335 shown in FIG. 11, the location of the UE is calculated and the result of the location calculation is notified.

[0162] In step ST2337 shown in Fig. 11, the LMF calculates the location of the UE. The LMF may perform the calculation using the positioning signal measurement result acquired in step ST2333, or may perform the calculation using the information on the repeater acquired in step ST2327, or may perform the calculation using both of the above.

[0163] In steps ST2339 and ST2341 shown in FIG. 11 , the LMF notifies the UE of the positioning result. The notification is performed via the AMF. Step ST2339 shows the notification from the LMF to the AMF, and step ST2341 shows the notification from the AMF to the UE.

[0164] In the example shown in Fig. 11, a case where positioning related to MO-LR is performed is shown, but the same may be applied to positioning related to a mobile-terminated location request (MT-LR) terminated in a UE, or to positioning related to a network-inducing location request (NI-LR). The same may be applied to figures subsequent to Fig. 11.

[0165] As another solution, the repeater may generate and transmit a positioning signal, which may be, for example, a PRS.

[0166] The base station may notify the repeater of the positioning signal configuration. The notification may include information about the time / frequency resources of the positioning signal, information about the beam used to transmit the positioning signal, or information about the code sequence of the positioning signal. The notification may also include a request for information about the repeater. The notification from the base station to the repeater may be performed using L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of the above.

[0167] The repeater may use the information obtained in the notification to configure the positioning signal. The repeater may start transmitting the positioning signal in response to the notification. The repeater may notify the base station that the configuration of the positioning signal has been completed. The notification may include information about the repeater itself. The information about the repeater may be the same as that described above. The notification from the repeater to the base station may use L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of the above.

[0168] Fig. 12 is a sequence diagram showing another example of a positioning procedure for a UE connecting to a base station via a repeater. In the example shown in Fig. 12, OTDOA positioning is performed. In Fig. 12, the repeater transmits a positioning signal. In Fig. 12, the same processes as in Fig. 11 are assigned the same numbers, and common explanations will be omitted.

[0169] Procedures 2301 and 2310 and steps ST2315 to ST2319 shown in FIG. 12 are the same as those in FIG.

[0170] In step ST2422 shown in FIG. 12 , the base station notifies the repeater of the configuration of the positioning signal. The notification may include information about the resource of the positioning signal, or information about the beam used to transmit the positioning signal. The notification may also include a request for information about the repeater. In step ST2422, L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of the above may be used. The repeater configures the positioning signal using the information received in step ST2422.

[0171] In step ST2425 shown in FIG. 12 , the repeater may notify the base station that the configuration of the positioning signal has been completed. This notification may include information about the repeater itself. The information about the repeater may be the same as that described above. In step ST2425, L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of the above may be used.

[0172] Steps ST2327 and ST2329 shown in FIG. 12 are the same as those in FIG.

[0173] 12, the repeater transmits a positioning signal to the UE. The transmission may be performed using the setting notified in step ST2422.

[0174] Steps ST2331, ST2333 and procedure ST2335 shown in FIG. 12 are the same as those in FIG.

[0175] The base station may notify devices other than the LMF of information about the repeater. The information about the repeater may be used in other core network devices. For example, the base station may notify the information to the AMF. The AMF may use the information, for example, to register the repeater. The AMF may, for example, use the location information of the repeater to determine whether or not to register the repeater in the network. This makes it possible, for example, to prevent the use of a repeater in a location where repeater transmission is not permitted.

[0176] The repeater may have a positioning function. For example, the repeater may have the same positioning function as the UE. The repeater itself may be positioned. The repeater may use the same method as the UE positioning, or may use the same signaling as the UE positioning, or may use the same signaling as the UE positioning.

[0177] The repeater may derive its own position. The derivation in the repeater may be performed, for example, in a manner similar to UE-based positioning (a positioning method in which a UE derives its own position). This makes it possible to reduce the amount of processing required for position calculation in the LMF, for example.

[0178] Positioning of the repeater and the UE may be performed simultaneously. The repeater and / or the UE may receive a positioning signal transmitted by the base station. The positioning signals received by the repeater and the UE may be the same or different. The UE may report the measurement results of the positioning signal to the LMF. The repeater may report information about its own repeater, such as the processing delay in its own repeater, to the base station. The base station may report this information to the LMF. The LMF may use the information to calculate the positions of the repeater and the UE. This may, for example, enable rapid positioning of the repeater and the UE.

[0179] The method disclosed in the first embodiment may be switched. For example, the transmission of a positioning signal from a base station and the generation and transmission of a positioning signal from a repeater may be switched. The base station may notify the repeater of information regarding the switch. The information may be, for example, information indicating whether to receive a positioning signal from the base station and transmit it to a UE, or to generate the signal in the repeater itself. The repeater may use the information to receive a positioning signal from the base station and transmit it to a UE, or to generate a positioning signal in the repeater itself and transmit it to a UE. This, for example, may enable improved flexibility in positioning.

[0180] The method disclosed in the first embodiment may be used in UE-based positioning. The LMF may notify the UE of information about repeaters. For this notification, LPP signaling, for example, signaling for providing LPP assistance data, or other LPP signaling may be used. As another example, the base station may notify the UE of the information about repeaters. For notification from the base station to the UE, RRC signaling, MAC signaling, or L1 / L2 signaling may be used. The UE may derive its own location using the information notified from the LMF and / or the base station. This makes it possible to improve the positioning accuracy of a UE connected to a base station via a repeater, for example, even in UE-based positioning.

[0181] According to the first embodiment, it is possible to ensure positioning accuracy even when positioning a UE connected to a base station via a repeater.

[0182] Embodiment 2. In positioning using uplink signals, a method similar to that in embodiment 1 may be applied. Positioning using uplink signals may be, for example, UL-TDOA (see Non-Patent Document 24 (3GPP TS38.305)).

[0183] For example, a UE connected to a base station via a repeater may transmit an SRS, and the base station may receive the SRS. The repeater may receive the SRS transmitted by the UE and transmit it to the base station. The repeater may amplify the SRS transmitted by the UE and transmit it to the base station. The repeater may perform the amplification and / or transmission operations together with other channels / signals.

[0184] The base station may notify the LMF of information about the repeater, which may include, for example, the same information as disclosed in the first embodiment.

[0185] The information about the repeater that is notified from the base station to the LMF may include information about the propagation delay from the base station to the repeater, or may include information about the location of the repeater, or may include both of the above information.

[0186] The repeater may notify the base station of the information about itself. For example, Msg3 in the four-step random access process, MsgA in the two-step random access process, or other signaling such as RRCSetupComplete (see Non-Patent Document 19 (3GPP TS38.331)) may be used for the notification. As another example, the information may be included in capabilities (e.g., UE capabilities) and notified.

[0187] The notification of the information from the repeater to the base station may be triggered by a request from the base station. The base station may request information about the repeater from the repeater in advance. The request from the base station to the repeater may use, for example, Msg2 in the four-step random access process, or other signaling, for example, signaling of an RRC startup request (see Non-Patent Document 19 (3GPP TS38.331)). As another example, the request may be notified by being included in a capability (e.g., UE capability) request.

[0188] Fig. 13 is a sequence diagram showing another example of a positioning procedure for a UE connected to a base station via a repeater. In the example shown in Fig. 13, UL-TDOA positioning is performed. In Fig. 13, the UE transmits an SRS, and the base station receives it. In Fig. 13, the same processes as in Fig. 11 are assigned the same numbers, and common explanations will be omitted.

[0189] The procedure 2301 and steps ST2315 and ST2317 shown in FIG. 13 are the same as those in FIG.

[0190] In Step ST2519 shown in FIG. 13 , the LMF requests information necessary for positioning from the base station. The request may use NRPPa signaling, for example, signaling of an NRPPa positioning information request. The request may include a request for information about repeaters. The information may include an instruction to configure an SRS. In Step ST2520, the base station configures the SRS. In Step ST2521, the base station instructs the UE to transmit an SRS. The instruction may use RRC signaling, for example, signaling of an RRC reconfiguration. The instruction may include information about the SRS configuration.

[0191] Steps ST2322 and ST2325 shown in FIG. 13 are the same as those in FIG.

[0192] In step ST2527 shown in FIG. 13 , the base station notifies the LMF of information necessary for positioning. For this notification, NRPPa signaling, for example, NRPPa positioning information response signaling, may be used. This notification may include information about the repeater. The information about the repeater may include, for example, information about the propagation delay from the base station to the repeater, information about the location of the repeater, or information about the processing delay in the repeater.

[0193] In Step ST2529 shown in FIG. 13 , the LMF requests the base station to start transmitting positioning signals from the UE. This request may be made using NRPPa signaling, for example, NRPPa POSITIONING ACTIVATION REQUEST signaling. This request may include information about the UE that is to start transmitting positioning signals. In Step ST2531, the base station instructs the UE to start transmitting positioning signals. This instruction may be made using L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of these. In Step ST2533, the base station notifies the LMF that the start of transmission of positioning signals has been completed. This notification may be made using NRPPa signaling, for example, NRPPa POSITIONING ACTIVATION RESPONSE signaling.

[0194] 13, the LMF requests the base station to measure a positioning signal. The request may be made using NRPPa signaling, for example, signaling of an NRPPa measurement request.

[0195] In Step ST2537 shown in Fig. 13, the UE transmits an SRS as a positioning signal to the base station. In Step ST2539, the base station measures the SRS from the UE.

[0196] In Step ST2541 shown in FIG. 13 , the base station notifies the LMF of the measurement result of the positioning signal. For this notification, NRPPa signaling, for example, NRPPa measurement response signaling, may be used. In Step ST2543, the LMF instructs the base station to stop transmission of the positioning signal from the UE. For this instruction, NRPPa signaling, for example, NRPPa POSITIONING DEACTIVATION signaling, may be used.

[0197] Procedure 2335 shown in Fig. 13 is the same as that in Fig. 11. The LMF may calculate the location of the UE using the measurement result included in Step ST2541, may calculate the location of the UE using the repeater information included in Step ST2527, or may determine the location of the UE using a combination of the above.

[0198] In the example shown in Figure 13, positioning related to MO-LR is shown, but the same may be applied to positioning related to a location information request (MT-LR) terminated in the UE, or to positioning related to a network-initiated location information request (NI-LR).

[0199] As another solution, the repeater may measure the positioning signal. The repeater may receive the positioning signal. The positioning signal received by the repeater may be, for example, an SRS. The base station may notify the repeater of the setting of the positioning signal. The repeater may start receiving the positioning signal in response to the notification. The repeater may notify the base station that the setting of the positioning signal has been completed. The notification may include information about the repeater itself. The information about the repeater may be the same as that described above.

[0200] The repeater may notify the base station of the reception result of the positioning signal. The notification may include information about the reception time of the positioning signal, information about the reception angle of the positioning signal, information about the reception power (e.g., SRS-RSRP) of the positioning signal, or information disclosed in the TRP Measurement Result described in Non-Patent Document 33 (3GPP TS38.455). The LMF may use the information to calculate the position of the UE.

[0201] Figure 14 is a sequence diagram showing another example of a positioning procedure for a UE connected to a base station via a repeater. In the example shown in Figure 14, UL-TDOA positioning is performed. In Figure 14, the UE transmits an SRS, and the repeater receives it. In Figure 14, the same processes as in Figures 11 and 13 are assigned the same numbers, and common explanations will be omitted.

[0202] The procedure 2301 and steps ST2315 and ST2317 shown in Fig. 14 are the same as those in Fig. 11. Steps ST2519 to ST2521 are the same as those in Fig. 13.

[0203] In step ST2622 shown in FIG. 14 , the base station notifies the repeater of the SRS configuration. The notification may include information about the SRS resource or information about the beam used to receive the SRS. The notification may include a request for information about the repeater. In step ST2622, L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of the above may be used. The repeater configures SRS reception using the information notified in step ST2622.

[0204] In step ST2625 shown in FIG. 14 , the repeater may notify the base station that the SRS reception setting has been completed. The notification may include information about the repeater itself. The information about the repeater may be the same as that described above. In step ST2625, L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of the above may be used.

[0205] Steps ST2527 to ST2535 shown in FIG. 14 are the same as those in FIG.

[0206] In step ST2636 shown in FIG. 14 , the base station instructs the repeater to start receiving the SRS. The notification may include information about the SRS resource or information about the beam used to receive the SRS. The notification may include a request for information about the repeater. In step ST2636, L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of the above may be used. Step ST2636 triggers the repeater to start receiving the SRS.

[0207] In Step ST2637 shown in Fig. 14, the UE transmits an SRS as a positioning signal to the repeater. In Step ST2639, the repeater measures the SRS from the UE.

[0208] In Step ST2640 shown in FIG. 14 , the repeater notifies the base station of the SRS measurement result. For the notification, L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of the above may be used. In Step ST2641, the base station notifies the LMF of the measurement result of the positioning signal. The notification may include information on the SRS measurement result at the repeater, which is included in Step ST2640. For the notification, NRPPa signaling, for example, signaling of an NRPPa measurement response, may be used.

[0209] Step ST2543 shown in Fig. 14 is the same as that in Fig. 13. Procedure 2335 shown in Fig. 14 is the same as that in Fig. 11. The LMF may calculate the location of the UE using the measurement result included in Step ST2641, may calculate the location of the UE using the repeater information included in Step ST2527, or may determine the location of the UE using a combination of the above-mentioned methods.

[0210] Positioning of the repeater and the UE may be performed simultaneously using uplink signals. The repeater and / or the base station may receive the positioning signal transmitted by the UE. The positioning signals received by the repeater and the base station may be the same or different. The repeater may notify the base station of the positioning signal reception result. The base station may notify the LMF of the positioning signal reception result of the base station. The notification from the base station to the LMF may include the positioning signal reception result at the repeater or information about the repeater. The LMF may calculate the positions of the repeater and the UE using the above information. This, for example, enables rapid positioning of the repeater and the UE.

[0211] The method disclosed in the second embodiment may be used in UE-based positioning. The LMF may notify the UE of information about repeaters. For this notification, LPP signaling, for example, signaling for providing LPP assistance data, or other LPP signaling may be used. As another example, the base station may notify the UE of the information about repeaters. For notification from the base station to the UE, RRC signaling, MAC signaling, or L1 / L2 signaling may be used. The UE may derive its own location using the information notified from the LMF and / or the base station. This makes it possible to improve the positioning accuracy of a UE connected to a base station via a repeater, for example, even in UE-based positioning.

[0212] The method disclosed in the second embodiment may be switched. For example, SRS measurement in the repeater and SRS measurement in the base station may be switched. The base station may notify the repeater of information regarding the switch. The information may be, for example, information indicating whether the base station or the repeater will measure the SRS. The repeater may use the information to receive the SRS from the UE and transmit it to the base station, or may measure the SRS in its own repeater. This may enable, for example, improved flexibility in the communication system.

[0213] According to the second embodiment, it is possible to ensure positioning accuracy even in positioning using uplink signals of a UE connected to a base station via a repeater.

[0214] Embodiment 3. Signaling may be transmitted and received between the repeater and the LMF. The signaling may be, for example, NRPPa signaling.

[0215] The base station may transmit NRPPa signaling from the LMF to the repeater. The repeater may receive the NRPPa signaling transmitted via the base station. The repeater may transmit NRPPa signaling for the LMF to the base station. The base station may receive the NRPPa signaling for the LMF transmitted from the repeater.

[0216] The NRPPa protocol may be terminated between the repeater and the LMF. As another example, the NRPPa protocol may be terminated between the base station and the LMF. The NRPPa protocol may be terminated between the base station and the repeater. The base station may relay NRPPa signaling transmitted from the LMF to the repeater, or may relay NRPPa signaling transmitted from the repeater to the LMF.

[0217] RRC signaling may be used for transmitting and receiving the NRPPa signaling. The NRPPa signaling may be encapsulated in the RRC signaling transmitted and received between the base station and the repeater. The NRPPa signaling may be signaling terminated between the base station and the repeater, or may be signaling terminated between the repeater and the LMF.

[0218] 15 is a diagram showing an example of a protocol stack in a repeater, a base station, an AMF, and an LMF. In the example shown in FIG. 15, the base station relays NRPPa signaling between the LMF and the repeater.

[0219] NAS signaling may be used for transmitting and receiving NRPPa signaling. NAS signaling may be transmitted and received between an AMF and a repeater. NRPPa signaling may be encapsulated in NAS signaling transmitted and received between an AMF and a repeater. The NRPPa signaling may be signaling terminated between a repeater and an LMF. The NAS signaling may be transmitted using RRC signaling. The NAS signaling may be encapsulated in RRC signaling.

[0220] 16 is a diagram showing another example of a protocol stack in a repeater, a base station, an AMF, and an LMF. In the example shown in FIG. 16, NRPPa signaling between the repeater and the LMF is transmitted and received using NAS signaling between the repeater and the AMF. NAS signaling between the repeater and the AMF is transmitted and received using RRC signaling between the repeater and the base station.

[0221] As an example of signaling between an LMF and a repeater, the LMF may request information about the repeater from the repeater. The information about the repeater may be the same as in embodiment 1. NRPPa signaling may be used for the request from the LMF to the repeater. For example, signaling for an OTDOA information request may be used, signaling for a positioning information request may be used, signaling for a TRP information request may be used, signaling for a positioning activation request may be used, signaling for a PRS configuration request may be used, signaling with a measurement pre-configuration request may be used, or signaling for assistance information control may be used. New NRPPa signaling may be provided. New NRPPa signaling may be used for the notification from the LMF to the repeater.

[0222] As an example of signaling between the LMF and the repeater, the repeater may notify the LMF of information about the repeater itself. The information about the repeater may be the same as that in embodiment 1. The repeater may perform the notification in response to the above-mentioned request from the LMF.

[0223] For example, NRPPa signaling may be used for the notification from the repeater to the LMF. For example, signaling of an OTDOA information response may be used, signaling of a positioning information response may be used, signaling of a positioning information update may be used, signaling of a TRP information response may be used, signaling of a positioning activation response may be used, signaling of a PRS configuration response may be used, signaling of a measurement pre-configuration confirmation may be used, or signaling of assistance information feedback may be used. This may, for example, avoid complexity in the communication system. New NRPPa signaling may be provided. For the notification from the repeater to the LMF, new NRPPa signaling may be used.

[0224] In the positioning procedure disclosed in the first embodiment, NRPPa signaling may be transmitted and received between the repeater and the LMF. For example, when a positioning signal is transmitted from a base station to a UE via a repeater, NRPPa signaling may be transmitted and received between the repeater and the LMF.

[0225] Fig. 17 is a sequence diagram showing another example of a positioning procedure for a UE connecting to a base station via a repeater. In the example shown in Fig. 17, OTDOA positioning is performed. In Fig. 17, a base station transmits a positioning signal. In Fig. 17, an example of positioning related to a location information request from a UE is shown. In Fig. 17, an example of UE-assisted positioning is shown. In Fig. 17, the same processes as in Fig. 11 are assigned the same numbers, and common explanations will be omitted.

[0226] Procedures 2301 and 2310 and steps ST2315 and ST2317 shown in FIG. 17 are the same as those in FIG.

[0227] In Step ST2919 shown in Fig. 17, the LMF requests information necessary for OTDOA from the base station. The request may use the same signaling as that in Step ST2319 shown in Fig. 11. The request may not include a request for information about repeaters.

[0228] 17, the LMF requests information about the repeater from the repeater. The request may be made using NRPPa signaling, for example, signaling of an NRPPa OTDOA information request.

[0229] 17, the repeater notifies the LMF of information related to the repeater itself. For the notification, NRPPa signaling, for example, NRPPa OTDOA information response signaling, may be used.

[0230] In Step ST2927 shown in FIG. 17 , the base station notifies the LMF of information necessary for OTDOA. For the notification, NRPPa signaling, for example, signaling of an NRPPa OTDOA information response, may be used. The notification may not include information about repeaters.

[0231] Steps ST2329 to ST2333 and procedure 2335 shown in FIG. 17 are the same as those in FIG.

[0232] As another example, when the repeater transmits a positioning signal to the UE, NRPPa signaling may be transmitted and received between the repeater and the LMF.

[0233] Fig. 18 is a sequence diagram showing another example of a positioning procedure for a UE connecting to a base station via a repeater. In the example shown in Fig. 18, OTDOA positioning is performed. In Fig. 30, the repeater transmits a positioning signal. In Fig. 18, the same processes as those in Figs. 11 and 12 are assigned the same numbers, and common explanations will be omitted.

[0234] Procedures 2301 and 2310 and steps ST2315 and ST2317 shown in FIG. 18 are the same as those in FIG.

[0235] In Step ST3022 shown in FIG. 18 , the LMF requests information necessary for OTDOA from the repeater. Step ST3022 may include a request for information about the repeater. The request may include information about an instruction to transmit a positioning signal. The request may be made using NRPPa signaling, for example, signaling of an NRPPa OTDOA information request.

[0236] In step ST3025 shown in FIG. 18 , the repeater notifies the LMF of information necessary for OTDOA. The notification may include information about the repeater itself. The notification may use NRPPa signaling, for example, signaling of an NRPPa OTDOA information response.

[0237] Step ST2329 shown in Fig. 18 is the same as that in Fig. 11. Step ST2430 is the same as that in Fig. 12. Steps ST2331, ST2333 and procedure ST2335 are the same as those in Fig. 11.

[0238] In the positioning procedure disclosed in the second embodiment, NRPPa signaling may be transmitted and received between the repeater and the LMF. For example, when the UE transmits an SRS and the base station receives it, NRPPa signaling may be transmitted and received between the repeater and the LMF.

[0239] Figure 19 is a sequence diagram showing another example of a positioning procedure for a UE connected to a base station via a repeater. In the example shown in Figure 19, UL-TDOA positioning is performed. In Figure 19, the UE transmits an SRS, and the base station receives it. In Figure 19, the same processes as in Figures 11 and 13 are assigned the same numbers, and common explanations will be omitted.

[0240] The procedure 2301 and steps ST2315 and ST2317 shown in FIG. 19 are the same as those in FIG.

[0241] In Step ST3119 shown in FIG. 19 , the LMF requests information necessary for positioning from the base station. The request may use NRPPa signaling, for example, signaling of an NRPPa positioning information request. The information may include an instruction to configure an SRS. The request may not include a request for information about repeaters.

[0242] Steps ST2520 and ST2521 shown in FIG. 19 are the same as those in FIG.

[0243] 19 , the LMF requests information about the repeater from the repeater. The request may be made using NRPPa signaling, for example, signaling of an NRPPa positioning information request.

[0244] In step ST3125 shown in FIG. 19 , the repeater notifies the LMF of information about the repeater itself. The information about the repeater may include, for example, information about a propagation delay from the base station to the repeater, information about the location of the repeater, or information about a processing delay in the repeater. For this notification, NRPPa signaling, for example, signaling of an NRPPa positioning information response, may be used.

[0245] In Step ST3127 shown in FIG. 19 , the base station notifies the LMF of information necessary for positioning. For the notification, NRPPa signaling, for example, signaling of an NRPPa positioning information response, may be used. The notification may not include information about repeaters.

[0246] Steps ST2529 to ST2543 shown in Fig. 19 are the same as those in Fig. 13. Procedure 2335 is the same as that in Fig. 11.

[0247] As another example, when the UE transmits the SRS and the repeater receives it, NRPPa signaling may be transmitted and received between the repeater and the LMF.

[0248] Figure 20 is a sequence diagram showing another example of a positioning procedure for a UE connected to a base station via a repeater. In the example shown in Figure 20, UL-TDOA positioning is performed. In Figure 20, the UE transmits an SRS, and the repeater receives it. In Figure 20, the same processes as those in Figures 11, 13, 14, and 19 are assigned the same numbers, and common explanations will be omitted.

[0249] Procedure 2301 and steps ST2315 and ST2317 shown in Fig. 20 are the same as those in Fig. 11. Step ST3119 is the same as those in Fig. 19. Steps ST2520 and ST2521 are the same as those in Fig. 13. Step ST3127 is the same as those in Fig. 19. Steps ST2529 to ST2533 are the same as those in Fig. 13.

[0250] In Step ST3235 shown in FIG. 20 , the LMF requests the repeater to measure the positioning signal. The request may use NRPPa signaling, for example, signaling of an NRPPa measurement request. The request may include information on the SRS resource or information on the beam used to receive the SRS. The request may also include a request for information on the repeater.

[0251] Steps ST2637 and ST2639 shown in FIG. 20 are the same as those in FIG.

[0252] In step ST3241 shown in FIG. 20 , the repeater notifies the LMF of the SRS measurement result. For the notification, NRPPa signaling, for example, signaling of an NRPPa measurement response, may be used. The notification may include information about the repeater itself.

[0253] Step ST2543 shown in Fig. 20 is the same as that in Fig. 13. Procedure 2335 is the same as that in Fig. 11.

[0254] According to the third embodiment, it is possible to reduce the amount of processing required for positioning signaling in the base station.

[0255] Modification 1 of Embodiment 3 As another example of the signaling transmitted and received between the repeater and the LMF, the signaling may be LPP signaling.

[0256] The base station may transmit LPP signaling from the LMF to the repeater. The repeater may receive the LPP signaling transmitted via the base station. The repeater may transmit LPP signaling for the LMF to the base station. The base station may receive the LPP signaling for the LMF transmitted from the repeater. The LPP protocol may be terminated between the repeater and the LMF.

[0257] NAS signaling may be used to transmit and receive LPP signaling. NAS signaling may be transmitted and received between an AMF and a repeater. LPP signaling may be encapsulated in the NAS signaling transmitted and received between an AMF and a repeater. The LPP signaling may be signaling terminated between a repeater and an LMF. The NAS signaling may be transmitted using RRC signaling. The NAS signaling may be encapsulated in the RRC signaling.

[0258] As an example of a protocol stack for LPP signaling in a repeater, a base station, an AMF, and an LMF, the one shown in Figure 16 may be used in which NRPPa is replaced with LPP.

[0259] As an example of signaling between an LMF and a repeater, the LMF may request information about the repeater from the repeater. The information about the repeater may be the same as in embodiment 1. LPP signaling may be used for the request from the LMF to the repeater. The signaling may be, for example, an LPP capability request, an LPP assistance data request, or an LPP location information request. New LPP signaling may be provided. The new LPP signaling may be used for the request from the LMF to the repeater.

[0260] As an example of signaling between the LMF and the repeater, the repeater may notify the LMF of information about the repeater itself. The information about the repeater may be the same as that in embodiment 1. The repeater may perform the notification in response to the above-mentioned request from the LMF.

[0261] The notification from the repeater to the LMF may use LPP signaling. The LPP signaling may be, for example, LPP capability provision, LPP assistance data provision, or LPP location information provision. New LPP signaling may be provided. The new LPP signaling may be used for the notification from the repeater to the LMF.

[0262] In the positioning procedure disclosed in the first embodiment, LPP signaling may be transmitted and received between the repeater and the LMF. For example, when a positioning signal is transmitted from a base station to a UE via the repeater, LPP signaling may be transmitted and received between the repeater and the LMF. As an example of an operation sequence, step ST2922 shown in Fig. 17 may be replaced with LPP signaling, for example, an LPP assistance data request, or step ST2925 shown in Fig. 17 may be replaced with LPP signaling, for example, an LPP assistance data provision.

[0263] As another example, when the repeater transmits a positioning signal to the UE, LPP signaling may be transmitted and received between the repeater and the LMF. As an example of an operation sequence, step ST3022 shown in Fig. 18 may be replaced with LPP signaling, for example, an LPP assistance data request, or step ST3025 shown in Fig. 18 may be replaced with LPP signaling, for example, an LPP assistance data provision.

[0264] In the positioning procedure disclosed in the second embodiment, LPP signaling may be transmitted and received between the repeater and the LMF. For example, when a UE transmits an SRS and a base station receives it, LPP signaling may be transmitted and received between the repeater and the LMF. As an example of an operation sequence, step ST3122 shown in Fig. 19 may be replaced with LPP signaling, for example, an LPP assistance data request, or step ST3125 shown in Fig. 19 may be replaced with LPP signaling, for example, LPP assistance data provision.

[0265] As another example, when a UE transmits an SRS and a repeater receives the SRS, transmission and reception of LPP signaling between the repeater and the LMF may be performed. As an example of an operation sequence, step ST3235 shown in Fig. 20 may be replaced with LPP signaling, for example, an LPP location information request or an LPP assistance data request, or step ST3241 shown in Fig. 20 may be replaced with LPP signaling, for example, an LPP location information provision or an LPP assistance data provision.

[0266] This first modification makes it possible to reduce the amount of processing required for positioning signaling in the base station, and also to avoid complexity in the design of the protocol stack of the repeater.

[0267] Although the present disclosure refers to a smart repeater, unless otherwise specified, it may be a reflector or a Reconfigurable Intelligent Surface (RIS), which, for example, enables extending the coverage of a base station while reducing power consumption in a communication system.

[0268] In this disclosure, it is described as a gNB or a cell, but unless otherwise specified, it may be a gNB or a cell.

[0269] The above-described embodiments and their modifications are merely examples, and the embodiments and their modifications can be freely combined. Furthermore, any of the components of the embodiments and their modifications can be modified or omitted as appropriate.

[0270] For example, in the above-described embodiments and their modifications, a subframe is an example of a time unit for communication in a fifth-generation communication system. A subframe may be a scheduling unit. In the above-described embodiments and their modifications, the processing described as being performed in subframe units may be performed in TTI units, slot units, subslot units, or minislot units.

[0271] For example, the methods disclosed in the above-described embodiments and their modified examples may be applied to services that use SL communication, not limited to V2X (Vehicle-to-everything) services, such as proximity-based services, public safety, communication between wearable devices, and communication between devices in factories.

[0272] 202 Communication terminal device (mobile terminal), 210 Communication system, 213, 240-1, 240-2, 750, 801 Base station device (NR base station, base station), 214 5G core unit, 215 Central unit, 216 Distributed unit, 217 Central unit for control plane, 218 Central unit for user plane, 219 TRP, 301, 403 Protocol processing unit, 302 Application unit, 304, 405 Encoder unit, 305, 406 Modulation unit, 306, 407 Frequency conversion unit, 307-1 to 307-4, 408-1 to 408-4 Antenna, 308, 409 Demodulation unit, 309, 410 Decoder unit, 310, 411, 526 Control unit, 401 EPC communication unit, 402 Other base station communication unit, 412 5GC communication unit, 521 Data Network communication unit, 522 Base station communication unit, 523 User plane communication unit, 523-1 PDU processing unit, 523-2 Mobility anchoring unit, 525 Control plane control unit, 525-1 NAS security unit, 525-2 Idle state mobility management unit, 527 Session management unit, 527-1 PDU session control unit, 527-2 UE IP address allocation unit, 751-1 to 751-8 Beam, 752 Cell, 803 Coverage, 805, 806, 811, 812, 905, 906 UE, 807, 808 UL / DL communication, 810, 814 SL communication, 901 IAB donor CU, 902 IAB donor DU, 903, 904 IAB node.

Claims

1. A communications system comprising: a core network side device equipped with a location management function for a fifth-generation wireless access system; a base station applied to the fifth-generation wireless access system; and a repeater that performs relay processing between the base station and a communications terminal; wherein the repeater notifies the core network side device of at least one of information regarding propagation delay between the connected base station and the repeater itself, information regarding the repeater's location, and information regarding processing delay in the repeater itself; the communications terminal measures a positioning signal transmitted by the repeater and notifies the core network side device of the measurement results of the positioning signal; and the core network side device calculates the location of the communications terminal based on the information notified from the repeater and the measurement results notified from the communications terminal.

2. A communication system comprising: a core network side device equipped with a location management function for a fifth-generation wireless access system; a base station applied to the fifth-generation wireless access system; and a repeater that performs relay processing between the base station and a communication terminal, wherein the repeater notifies the core network side device of at least one of information regarding propagation delay between the connected base station and the repeater itself, information regarding the location of the repeater itself, and information regarding processing delay in the repeater itself, and further measures a positioning signal transmitted by the communication terminal and notifies the core network side device of the measurement results of the positioning signal, and the core network side device calculates the position of the communication terminal based on the information notified by the repeater and the measurement results.

Images