communication systems

Abstract

To realize a communication system capable of accurately locating the position of a communication terminal even when a base station moves. [Solution] The communication system 210 comprises a base station 217 and a communication terminal (UE) 202 connected to the base station 217, and the base station 217 transmits the reception result of the uplink positioning signal transmitted by the communication terminal 202 and the location information of the base station 217 to a positioning execution device, which is a device having a positioning function for deriving the location of the communication terminal 202, and the communication terminal 202 transmits the reception result of the downlink positioning signal transmitted by the base station 217 to the positioning execution device.

Description

[Technical Field]

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

[0002] 3GPP (3rd Generation Partnership Project), a standardization organization for mobile communication systems, is considering a communication method called Long Term Evolution (LTE) for the wireless section and System Architecture Evolution (SAE) for the overall system configuration including the core network and radio access network (hereinafter collectively referred to as the network) (see, for example, Non-Patent Documents 1 to 5). This communication method is also called the 3.9G (3.9 Generation) system.

[0003] LTE uses OFDM (Orthogonal Frequency Division Multiplexing) for downlink and SC-FDMA (Single Carrier Frequency Division Multiple Access) for uplink as its access method. Unlike W-CDMA (Wideband Code Division Multiple Access), LTE does not include circuit switching and is only a packet communication method.

[0004] The decisions made by 3GPP regarding the frame configuration in the LTE system, as described in Non-Patent Document 1 (Chapter 5), will be explained using Figure 1. Figure 1 is an explanatory diagram showing the configuration of a radio frame used in an LTE communication system. In Figure 1, one radio frame is 10 ms. The radio frame is divided into 10 equally sized subframes. The subframe is divided into two equally sized slots. The first and sixth subframes of each radio frame include a downlink synchronization signal. The synchronization signals include a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS).

[0005] The decisions made by 3GPP regarding the channel configuration in the LTE system are described in Non-Patent Document 1 (Chapter 5). It is assumed that the same channel configuration as that of a non-CSG cell is used in a CSG (Closed Subscriber Group) cell.

[0006] The Physical Broadcast Channel (PBCH) is a channel for downlink transmission from a base station (hereinafter simply referred to as a "base station") to a communication terminal (hereinafter simply referred to as a "communication terminal") such as a mobile terminal (hereinafter simply referred to as a "mobile terminal"). A BCH transport block is mapped to four subframes in a 40 ms interval. There is no explicit signaling of the 40 ms timing.

[0007] The Physical Control Format Indicator Channel (PCFICH) is a channel for downlink transmission from a base station to a communication terminal. The PCFICH notifies the communication terminal of the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols used for PDCCHs. The PCFICH is transmitted every subframe.

[0008] The Physical Downlink Control Channel (PDCCH) is a channel for downlink transmission from a base station to a communication terminal. The PDCCH reports 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 also one of the transport channels described below, and Hybrid Automatic Repeat reQuest (HARQ) information for the DL-SCH. The PDCCH carries an uplink scheduling grant. The PDCCH carries Acknowledgement (Ack) / Negative Acknowledgement (Nack), which are response signals to uplink transmissions. The PDCCH is also called an L1 / L2 control signal.

[0009] The Physical Downlink Shared Channel (PDSCH) is a channel for downlink transmission from a base station to a communication terminal. A Downlink Shared Channel (DL-SCH), which is a transport channel, and a PCH, which is also a transport channel, are mapped to the PDSCH.

[0010] A physical multicast channel (PMCH) is a channel for downlink transmission from a base station to communication terminals, and a multicast channel (MCH), which is a transport channel, is mapped to the PMCH.

[0011] The Physical Uplink Control Channel (PUCCH) is a channel for uplink transmission from a communication terminal to a base station. The PUCCH carries Ack / Nack, which are response signals to downlink transmissions. The PUCCH carries Channel State Information (CSI). The CSI consists of a Rank Indicator (RI), a Precoding Matrix Indicator (PMI), and a Channel Quality Indicator (CQI) report. The RI is information on the rank of the channel matrix in MIMO. The PMI is information on the precoding weight matrix used in MIMO. The CQI is quality information that indicates the quality of received data or the quality of the communication path. The PUCCH also carries a Scheduling Request (SR).

[0012] 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.

[0013] The Physical Hybrid ARQ Indicator Channel (PHICH) is a channel for downlink transmission from a base station to a communication terminal. The PHICH carries Ack / Nack, which are response signals to uplink transmission. The 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.

[0014] Downlink reference signals (RS) are symbols known in LTE communication systems. The following five types of downlink reference signals are defined: Cell-specific Reference Signal (CRS), MBSFN Reference Signal, UE-specific reference signal Demodulation Reference Signal (DM-RS), Positioning Reference Signal (PRS), and Channel State Information Reference Signal (CSI-RS). Measurement of the physical layer of a communication terminal includes measurement of the reference signal received power (RSRP).

[0015] Similarly, the uplink reference signal is a symbol known in LTE communication systems. Two types of uplink reference signals are defined: a data demodulation reference signal (DM-RS) and a sounding reference signal (SRS).

[0016] The transport channels described in Non-Patent Document 1 (Chapter 5) will be explained 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).

[0017] Retransmission control using HARQ (Hybrid ARQ) is applied to the Downlink Shared Channel (DL-SCH). DL-SCH can be broadcast to the entire coverage of a base station (cell). DL-SCH supports dynamic or semi-static resource allocation. Semi-static resource allocation is also called persistent scheduling. DL-SCH supports discontinuous reception (DRX) in communication terminals to reduce power consumption of communication terminals. DL-SCH is mapped to the Physical Downlink Shared Channel (PDSCH).

[0018] The Paging Channel (PCH) supports DRX in communication terminals to enable low power consumption in 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.

[0019] The Multicast Channel (MCH) is used for broadcasting to the entire coverage of a base station (cell). The MCH supports SFN combining of MBMS (Multimedia Broadcast Multicast Service) services (MTCH and MCCH) in multi-cell transmission. The MCH supports semi-static resource allocation. The MCH is mapped to the PMCH.

[0020] Among the uplink transport channels, the Uplink Shared Channel (UL-SCH) is subject to retransmission control using HARQ (Hybrid ARQ). The UL-SCH supports dynamic or semi-static resource allocation. The UL-SCH is mapped to the Physical Uplink Shared Channel (PUSCH).

[0021] The Random Access Channel (RACH) is limited to control information. The RACH is subject to collision risk. The RACH is mapped to the Physical Random Access Channel (PRACH).

[0022] We will explain HARQ. HARQ is a technology that improves the communication quality of a transmission channel by combining Automatic Repeat reQuest (ARQ) and Forward Error Correction. HARQ has the advantage that error correction works effectively through retransmission even on transmission channels where communication quality varies. In particular, by combining the reception results of the initial transmission and the retransmission when retransmitting, it is possible to achieve further quality improvement.

[0023] An example of a retransmission method will be explained 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 sending side. The sending 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 sending side. The sending side, having received the "Ack," will send the next data.

[0024] The logical channels described in Non-Patent Document 1 (Chapter 6) will be explained below. The Broadcast Control Channel (BCCH) is a downlink channel for broadcast 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.

[0025] The Paging Control Channel (PCCH) is a downlink channel for transmitting paging information and changes to system information. The PCCH is used when the network does not know the cell location of the communication terminal. The PCCH, which is a logical channel, is mapped to the Paging Channel (PCH), which is a transport channel.

[0026] A Common Control Channel (CCCH) is a channel for transmission control information between a communication terminal and a base station. CCCH is used when a communication terminal does not have an RRC connection with the network. In the downlink direction, CCCH is mapped to a Downlink Shared Channel (DL-SCH), which is a transport channel. In the uplink direction, CCCH is mapped to an Uplink Shared Channel (UL-SCH), which is a transport channel.

[0027] The Multicast Control Channel (MCCH) is a downlink channel for point-to-multipoint transmission. The MCCH is used to transmit MBMS control information for one or several MTCHs from the network to communication terminals. The MCCH is used only by communication terminals receiving MBMS. The MCCH is mapped to the Multicast Channel (MCH), which is a transport channel.

[0028] A dedicated control channel (DCCH) is a channel that transmits dedicated control information between a communication terminal and a network on a one-to-one basis. The DCCH is used when the communication terminal is in an RRC connection. 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.

[0029] A Dedicated Traffic Channel (DTCH) is a one-to-one communication channel for transmitting user information to an individual 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).

[0030] The Multicast Traffic Channel (MTCH) is a downlink channel for transmitting traffic data from the network to communication terminals. The MTCH is a channel used only by communication terminals receiving MBMS. The MTCH is mapped to the Multicast Channel (MCH).

[0031] CGI stands for Cell Global Identifier. ECGI stands for E-UTRAN Cell Global Identifier. Closed Subscriber Group (CSG) cells are introduced in LTE, LTE-A (Long Term Evolution Advanced) (described below), and UMTS (Universal Mobile Telecommunication System).

[0032] 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 enable the communication terminal to be called, in other words, to allow the communication terminal to receive calls. The area used for tracking the location of this communication terminal is called a tracking area.

[0033] 3GPP is also working on the development of the Long Term Evolution Advanced (LTE-A) standard as Release 10 (see Non-Patent Documents 3 and 4). LTE-A is based on the LTE wireless communication system, and is configured by adding several new technologies to it.

[0034] In the LTE-A system, carrier aggregation (CA) is being considered, which aggregates two or more component carriers (CCs) (also called "aggregation") to support wider frequency bandwidths (transmission bandwidths) up to 100 MHz. CA is described in Non-Patent Document 1.

[0035] 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). In the downlink, the carrier corresponding to the PCell is the downlink primary component carrier (DL PCC). In the uplink, the carrier corresponding to the PCell is the uplink primary component carrier (UL PCC).

[0036] Depending on the UE's capabilities, a secondary cell (SCell) is configured to form a serving cell set together with the PCell. In the downlink, the carrier corresponding to the SCell is the downlink secondary component carrier (DL SCC). In the uplink, the carrier corresponding to the SCell is the uplink secondary component carrier (UL SCC).

[0037] A set of serving cells, which includes one PCell and one or more SCells, is configured for one UE.

[0038] Furthermore, new technologies for LTE-A include wider bandwidth extension and Coordinated Multiple Point transmission and reception (CoMP) technology. CoMP, which is being considered for LTE-A by 3GPP, is described in Non-Patent Document 1.

[0039] Furthermore, in order to handle future massive traffic volumes, 3GPP is considering using small eNBs (hereinafter sometimes referred to as "small-scale base station devices") that configure small cells. For example, technologies are being considered that aim to increase communication capacity by installing a large number of small eNBs and configuring a large number of small cells to improve frequency utilization efficiency. Specifically, there is dual connectivity (abbreviated as DC), in which a UE connects to two eNBs to communicate. DC is described in Non-Patent Document 1.

[0040] Of the eNBs that perform dual connectivity (DC), one may be referred to as a "master eNB (abbreviated as MeNB)" and the other as a "secondary eNB (abbreviated as SeNB)."

[0041] Mobile network traffic volume is on the rise, and communication speeds are also increasing. Once LTE and LTE-A are fully operational, communication speeds are expected to increase even further.

[0042] Furthermore, in response to the increasing sophistication of mobile communications, fifth-generation (hereinafter sometimes referred to as "5G") wireless access systems are being considered, with the goal of launching services after 2020. For example, in Europe, an organization called METIS has compiled requirements for 5G (see Non-Patent Document 5).

[0043] The requirements for a 5G wireless access system are that it will have 1,000 times the system capacity, 100 times the data transmission speed, one-tenth (1 / 10) 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 lower equipment costs.

[0044] To meet these demands, 3GPP is currently working on 5G standards as Release 15 (see Non-Patent Documents 6 to 19). 5G wireless access technology is called "New Radio Access Technology" ("New Radio" is abbreviated as "NR").

[0045] The NR system is being developed based on the LTE system and LTE-A system, but the following changes and additions have been made to the LTE system and LTE-A system.

[0046] The NR access method uses OFDM in the downlink direction and OFDM and DFT-s-OFDM (DFT-spread-OFDM) in the uplink direction.

[0047] NR allows the use of higher frequencies than LTE in order to improve transmission speeds and reduce processing delays.

[0048] In NR, cell coverage is ensured by forming a narrow beam-shaped transmission and reception range (beamforming) and changing the direction of the beam (beam sweeping).

[0049] The NR frame structure supports various subcarrier spacings, i.e., various numerologies. In NR, regardless of the numerology, one subframe is 1 millisecond and one slot consists of 14 symbols. Furthermore, the number of slots included in one subframe is one in numerologies with a subcarrier spacing of 15 kHz, but increases in proportion to the subcarrier spacing in other numerologies (see Non-Patent Document 13 (3GPP TS38.211)).

[0050] In NR, downlink synchronization signals are transmitted from a base station at a predetermined interval and for a predetermined duration as synchronization signal bursts (hereinafter sometimes referred to as SS bursts). An SS burst is composed of synchronization signal blocks (hereinafter sometimes referred to as SS blocks) for each beam of the base station.

[0051] The base station transmits the SS block for each beam during the SS burst, changing the beam. The SS block consists of the P-SS, S-SS, and PBCH.

[0052] In NR, the influence of phase noise is reduced by adding a Phase Tracking Reference Signal (PTRS) as a downlink reference signal for NR. PTRS is also added to the uplink reference signal, just like in the downlink.

[0053] In NR, slot format indication (SFI) has been added to the information contained in the PDCCH in order to flexibly switch between DL and UL within a slot.

[0054] In addition, in NR, the base station pre-configures 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.

[0055] 3GPP is considering the following DC forms: DC by LTE base stations and NR base stations connected to EPC, DC by NR base stations connected to a 5G core system, and DC by LTE base stations and NR base stations connected to a 5G core system (see Non-Patent Documents 12, 16, and 19).

[0056] Additionally, 3GPP is studying several new technologies, such as positioning technology (see Non-Patent Documents 24 to 27) and integrated access and backhaul (IAB) (see Non-Patent Documents 16, 28, and 29).

[0057] As a positioning technology, for example, a positioning method using round-trip delay times between a UE and multiple base stations (Multi-Round Trip Time: Multi-RTT) is being studied (see Non-Patent Document 24).

[0058] As IAB, for example, multiplexing within radio resources and reducing latency of access links, which are links between UEs and base stations, and backhaul links, which are links between base stations, are being considered (see Non-Patent Documents 16, 28, and 29).

[0059] 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 below and the 5G core system (see Non-Patent Documents 1, 16, 20, 21, 22, and 23). Services using SL communication include, for example, vehicle-to-everything (V2X) services and proximity services. [Prior art documents] [Non-patent literature]

[0060] [Non-Patent Document 1] 3GPP TS36.300 V16.2.0 [Non-patent document 2] 3GPP S1-083461 [Non-patent document 3] 3GPP TR36.814 V9.2.0 [Non-patent document 4] 3GPP TR36.912 V16.0.0 [Non-patent document 5] “Scenarios, requirements and KPIs for 5G mobile and wireless system”, ICT-317669-METIS / D1.1 [Non-patent document 6] 3GPP TR23.799 V14.0.0 [Non-Patent Document 7] 3GPP TR38.801 V14.0.0 [Non-patent document 8] 3GPP TR38.802 V14.2.0 [Non-Patent Document 9] 3GPP TR38.804 V14.0.0 [Non-Patent Document 10] 3GPP TR38.912 V16.0.0 [Non-Patent Document 11] 3GPP RP-172115

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[0061] In the above positioning technology, when positioning a communication terminal, information about the relative positions of the communication terminal to be positioned and one or more base stations with which it can communicate is used. Therefore, when the base station moves, the accuracy of the information used for positioning deteriorates, i.e., the positioning accuracy deteriorates.

[0062] In view of the above-mentioned problems, one of the objects of the present disclosure is to realize a communication system that can accurately locate the position of a communication terminal even when a base station is moving. [Means for solving the problem]

[0063] The communication system according to the present disclosure comprises a base station and a communication terminal connected to the base station, and the base station transmits the reception result of the uplink positioning signal transmitted by the communication terminal and the position information of the base station to a positioning execution device, which is a device having a positioning function for deriving the position of the communication terminal, and the communication terminal transmits the reception result of the downlink positioning signal transmitted by the base station to the positioning execution device. [Effects of the Invention]

[0064] According to the present disclosure, it is possible to realize a communication system that can accurately locate the position of a communication terminal even when a base station is moving.

[0065] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0066] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a radio frame used in an LTE communication system. [Figure 2] 1 is a block diagram showing the overall configuration of an LTE communication system 200 being discussed in 3GPP. [Figure 3] FIG. 2 is a block diagram showing the overall configuration of a communication system 210 conforming to the NR standard under discussion in 3GPP. [Figure 4] This is a diagram illustrating the configuration of DC using eNB and gNB connected to EPC. [Figure 5] This is a diagram of the DC configuration using gNB connected to the NG core. [Figure 6] This is a diagram illustrating the configuration of DC using eNB and gNB connected to the NG core. [Figure 7] This is a diagram illustrating the configuration of DC using eNB and gNB connected to the NG core. [Figure 8] FIG. 3 is a block diagram showing the configuration of a mobile terminal 202 shown in FIG. [Figure 9] FIG. 3 is a block diagram showing the configuration of a base station 203 shown in FIG. [Figure 10] FIG. 2 is a block diagram illustrating the configuration of an MME. [Figure 11] FIG. 5 is a block diagram showing the configuration of the GC unit. [Figure 12] 1 is a flowchart showing an outline of operations from cell search to standby operation performed by a communication terminal (UE) in an LTE communication system. [Figure 13] FIG. 1 is a diagram illustrating an example of a cell configuration in an NR system. [Figure 14] FIG. 10 is a sequence diagram showing an example of a UE positioning sequence in which a base station notifies an LMF of a combination of the position of the base station and time information, in accordance with the first embodiment. [Figure 15]FIG. 10 is a sequence diagram showing another example of the UE positioning sequence in which the base station notifies the LMF of a combination of the position of the base station and time information, in accordance with the first embodiment. [Figure 16] FIG. 10 is a sequence diagram showing the operation of notifying a serving base station of a combination of the position of the base station and time information from a surrounding base station in a UE positioning sequence when the base station has an LMF, in accordance with a first variant of the first embodiment. [Figure 17] FIG. 10 is a sequence diagram showing the operation of a serving base station to notify the UE of a combination of location and time information at the base station itself and neighboring base stations in a UE positioning sequence when the UE has an LMF, for a second variant of the first embodiment. [Figure 18] FIG. 11 is a sequence diagram showing an example of a UE positioning sequence including a process in which a DU notifies a CU of the location of the DU, according to the second embodiment. [Figure 19] FIG. 11 is a sequence diagram showing an example of a positioning sequence of an IAB node according to the third embodiment. [Figure 20] FIG. 11 is a sequence diagram showing an example of a positioning sequence in which the positions of an IAB node and a UE are simultaneously measured, according to the third embodiment. [Figure 21] FIG. 13 is a diagram illustrating an example of a protocol stack in the case where a CU has an adaptation layer, according to the fourth embodiment. [Figure 22] FIG. 13 is a diagram illustrating an example of a protocol stack in the case where a DU has an adaptation layer, according to the fourth embodiment. [Figure 23] FIG. 13 is a diagram illustrating an example of a protocol stack in the case where a BAP is placed above an adaptation layer, in accordance with a first modification of the fourth embodiment. [Figure 24] FIG. 13 is a diagram illustrating an example of a protocol stack in a case where an adaptation layer is placed above a BAP, in accordance with a first modification of the fourth embodiment. [Figure 25]FIG. 13 is a diagram illustrating another example of a protocol stack in the case where an adaptation layer is placed above a BAP, in accordance with the first modification of the fourth embodiment. [Figure 26] This figure shows an example of a protocol stack for variant example 1 of embodiment 4, where an adaptation layer is used between the relay UE and the IAB node, and a BAP is used between the IAB nodes and between the IAB node and the IAB donor DU. DETAILED DESCRIPTION OF THE INVENTION

[0067] Embodiment 1 Fig. 2 is a block diagram showing the overall configuration of an LTE communication system 200 being discussed in 3GPP. Fig. 2 will now be described. The radio access network is called E-UTRAN (Evolved Universal Terrestrial Radio Access Network) 201. A mobile terminal device (hereinafter referred to as "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 "base station (E-UTRAN NodeB: eNB)") 203, and transmits and receives signals via wireless communication.

[0068] 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."

[0069] If control protocols for mobile terminals 202, such as RRC (Radio Resource Control), and user planes (hereinafter sometimes referred to as U-Planes), such as PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer), terminate at base stations 203, E-UTRAN is composed of one or more base stations 203.

[0070] The control protocol RRC (Radio Resource Control) between the mobile terminal 202 and the base station 203 performs broadcasting, paging, RRC connection management, etc. The states of the base station 203 and the mobile terminal 202 in RRC include RRC_IDLE and RRC_CONNECTED.

[0071] In RRC_IDLE, PLMN (Public Land Mobile Network) selection, system information (SI) broadcast, paging, cell reselection, 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.

[0072] The base station 203 is configured by one or more eNBs 207. A system configured by the core network EPC (Evolved Packet Core) and the radio access network E-UTRAN 201 is called an EPS (Evolved Packet System). The core network EPC and the radio access network E-UTRAN 201 are sometimes collectively referred to as a "network."

[0073] The eNB 207 is connected to a Mobility Management Entity (MME), or a Serving Gateway (S-GW), or an MME / S-GW unit (hereinafter sometimes referred to as an "MME unit") 204 including an MME and an S-GW via an S1 interface, and control information is communicated between the eNB 207 and the MME unit 204. Multiple MME units 204 may be connected to one eNB 207. The eNBs 207 are connected to each other via an X2 interface, and control information is communicated between the eNBs 207.

[0074] The MME unit 204 is an upper device, specifically an upper node, and controls the connection between the eNB 207, which is a base station, and the mobile terminal (UE) 202. The MME unit 204 constitutes the EPC, which is a core network. The base station 203 constitutes the E-UTRAN 201.

[0075] Base station 203 may configure one cell or multiple cells. Each cell has a predetermined range as coverage, which is the range within which communication with mobile terminal 202 is possible, and performs wireless communication with mobile terminal 202 within the coverage. When one base station 203 configures multiple cells, each cell is configured to be able to communicate with mobile terminal 202.

[0076] Figure 3 is a block diagram showing the overall configuration of a 5G communication system 210 being discussed in 3GPP. The following describes Figure 3. The radio access network is referred to as a Next Generation Radio Access Network (NG-RAN) 211. The UE 202 is capable of wireless communication with an NR 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 core network is referred to as a 5G Core (5GC).

[0077] If control protocols for UE202, such as RRC (Radio Resource Control), and user planes (hereinafter sometimes referred to as U-Planes), such as SDAP (Service Data Adaptation Protocol), PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer), terminate at an NR base station 213, the NG-RAN is composed of one or more NR base stations 213.

[0078] The function of the control protocol RRC (Radio Resource Control) between the UE 202 and the NR base station 213 is the same as that of LTE. The states of the NR base station 213 and the UE 202 in the RRC include RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE.

[0079] RRC_IDLE and RRC_CONNECTED are the same as those in the LTE system. RRC_INACTIVE maintains the connection between the 5G core and the NR base station 213, and performs system information (SI), paging, cell reselection, mobility, and the like.

[0080] The gNB 217 is connected to an AMF / SMF / UPF 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), or an AMF, SMF, and UPF, via an NG interface. Control information and / or user data are communicated between the gNB 217 and the 5GC unit 214. The NG interface is a collective term for the N2 interface between the gNB 217 and the AMF, the N3 interface between the gNB 217 and the UPF, the N11 interface between the AMF and the SMF, and the N4 interface between the UPF and the SMF. Multiple 5GC units 214 may be connected to one gNB 217. The gNBs 217 are connected to each other via an Xn interface, and control information and / or user data are communicated between the gNBs 217.

[0081] The 5GC unit 214 is an upper device, specifically an upper node, and distributes paging signals to one or more base stations 203 and / or base station 213. The 5GC unit 214 also performs mobility control in an idle state. The 5GC unit 214 manages a tracking area list when the mobile terminal 202 is in an idle state, an inactive state, and an active state. The 5GC unit 214 initiates a paging protocol by transmitting a paging message to a cell belonging to a tracking area in which the mobile terminal 202 is registered.

[0082] The NR base station 213 may configure one or more cells, similar to the base station 203. When one NR base station 213 configures multiple cells, each cell is configured to be able to communicate with the UE 202.

[0083] The gNB 217 may be divided into a central unit (hereinafter, sometimes referred to as CU) 218 ​​and distributed units (hereinafter, sometimes referred to as DUs) 219. One CU 218 is configured in the gNB 217. One or more DUs 219 are configured in the gNB 217. The CU 218 is connected to the DU 219 via an F1 interface, and control information and / or user data is communicated between the CU 218 and the DU 219.

[0084] A 5G communication system may include a Unified Data Management (UDM) function and a Policy Control Function (PCF) described in Non-Patent Document 21 (3GPP TS23.501). The UDM and / or PCF may be included in the 5GC unit 214 in FIG.

[0085] In a 5G communication system, a Location Management Function (LMF) described in Non-Patent Document 24 (3GPP TS38.305) may be provided. The LMF may be connected to a base station via an AMF as disclosed in Non-Patent Document 30 (3GPP TS23.263).

[0086] A 5G communication system may include a Non-3GPP Interworking Function (N3IWF) described in Non-Patent Document 21 (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.

[0087] Fig. 4 is a diagram showing a DC configuration by eNBs and gNBs connected to EPC. In Fig. 4, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Fig. 4, eNB223-1 serves as the master base station, and gNB224-2 serves as the secondary base station (this DC configuration may be referred to as EN-DC). Fig. 4 shows an example in which U-Plane connection between MME unit 204 and gNB224-2 is made via eNB223-1, but it may also be made directly between MME unit 204 and gNB224-2.

[0088] Figure 5 is a diagram showing the configuration of DC by a gNB connected to an NG core. In Figure 5, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Figure 5, gNB 224-1 is the master base station, and gNB 224-2 is the secondary base station (this DC configuration may be referred to as NR-DC). Figure 5 shows an example in which U-Plane connection between 5GC unit 214 and gNB 224-2 is made via gNB 224-1, but it may also be made directly between 5GC unit 214 and gNB 224-2.

[0089] Figure 6 is a diagram showing a DC configuration by eNB and gNB connected to the NG core. In Figure 6, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Figure 6, eNB226-1 is the master base station, and gNB224-2 is the secondary base station (this DC configuration may be referred to as NG-EN-DC). Figure 6 shows an example in which U-Plane connection between 5GC unit 214 and gNB224-2 is made via eNB226-1, but it may also be made directly between 5GC unit 214 and gNB224-2.

[0090] Figure 7 is a diagram showing another configuration of DC by eNB and gNB connected to the NG core. In Figure 7, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Figure 7, gNB224-1 is the master base station, and eNB226-2 is the secondary base station (this DC configuration may be referred to as NE-DC). Figure 7 shows an example in which U-Plane connection between 5GC unit 214 and eNB226-2 is made via gNB224-1, but it may also be made directly between 5GC unit 214 and eNB226-2.

[0091] FIG. 8 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. 8 will be described. First, control data from protocol processing unit 301 and user data from application unit 302 are stored in transmission data buffer unit 303. The data stored in transmission data buffer unit 303 is passed to encoder unit 304, where it is subjected to encoding processes such as error correction. Some data may be output directly from transmission data buffer unit 303 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 203 from antennas 307-1 to 307-4. Although FIG. 8 illustrates an example in which the number of antennas is four, the number of antennas is not limited to four.

[0092] Furthermore, the reception process of the mobile terminal 202 is performed as follows. Radio signals from the base station 203 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 converter 306, and demodulated by the demodulator 308. The demodulator 308 may also perform weight calculation and multiplication. The demodulated data is passed to the decoder 309, where it is decoded, such as for error correction. Of the decoded data, the control data is passed to the protocol processor 301, and the user data is passed to the application unit 302. The series of processes of the mobile terminal 202 is controlled by the controller 310. Therefore, although not shown in FIG. 8 , the controller 310 is connected to each of the units 301 to 309. The controller 310 is realized, for example, by a processing circuit including a processor and a memory. That is, the controller 310 is realized by the processor executing a program in which the series of processes of the mobile terminal 202 are described. A program describing a series of processes of 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. Control unit 310 may be realized by a dedicated processing circuit such as an FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), or DSP (Digital Signal Processor). In FIG. 8, the number of antennas used by mobile terminal 202 for transmission and the number of antennas used for reception may be the same or different.

[0093] 2. The transmission process of the base station 203 shown in FIG. 9 will be described. The EPC communication unit 401 transmits and receives data between the base station 203 and the EPC (such as the MME unit 204). The 5GC communication unit 412 transmits and receives data between the base station 203 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. The control data from the protocol processing unit 403, and the 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 stored in the transmission data buffer unit 404.

[0094] The data stored in transmission data buffer unit 404 is passed to encoder unit 405, where it undergoes encoding processing such as error correction. Some data may be output directly from transmission data buffer unit 404 to modulation unit 406 without undergoing encoding processing. The encoded data is modulated by modulation unit 406. MIMO precoding may be performed by modulation unit 406. The modulated data is converted into a baseband signal, and then output to frequency conversion unit 407, where it is converted into a radio transmission frequency. Thereafter, a transmission signal is transmitted to one or more mobile terminals 202 from antennas 408-1 to 408-4. Although FIG. 9 illustrates an example in which the number of antennas is four, the number of antennas is not limited to four.

[0095] Furthermore, the reception process of the base station 203 is performed as follows. A radio signal from one or more mobile terminals 202 is received by the antenna 408. 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 processes such as error correction are performed. Of the decoded data, control data is passed to the protocol processing unit 403, the 5GC communication unit 412, the EPC communication unit 401, or the other base station communication unit 402, and user data is passed to the 5GC communication unit 412, the EPC communication unit 401, or the other base station communication unit 402. A series of processes of the base station 203 is controlled by the control unit 411. Therefore, although the control unit 411 is omitted in FIG. 9, it is connected to each of the units 401 to 410, 412. Similar to control unit 310 of mobile terminal 202 described above, control unit 411 is realized by a processing circuit including a processor and a memory, or a dedicated processing circuit such as an FPGA, ASIC, or DSP. In Fig. 9, the number of antennas used by base station 203 for transmission and the number of antennas used for reception may be the same or different.

[0096] 9 is a block diagram showing the configuration of base station 203, but a similar configuration may also be used for base station 213. In addition, in FIGS. 8 and 9, the number of antennas in mobile terminal 202 and the number of antennas in base station 203 may be the same or different.

[0097] 10 is a block diagram showing the configuration of an MME. FIG. 10 shows the configuration of an MME 204a included in the MME unit 204 shown in FIG. 2 described above. A PDN GW communication unit 501 transmits and receives data between the MME 204a and a PDN GW (Packet Data Network Gateway). A base station communication unit 502 transmits and receives data via the S1 interface between the MME 204a and a base station 203. If the data received from the PDN GW is user data, the user data is passed from the PDN GW communication unit 501 to the base station communication unit 502 via a user plane communication unit 503, and transmitted to one or more base stations 203. If the data received from the base station 203 is user data, the user data is passed from the base station communication unit 502 to the PDN GW communication unit 501 via the user plane communication unit 503, and transmitted to the PDN GW.

[0098] If the data received from the PDN GW is control data, the control data is passed from the PDN GW communication unit 501 to the control plane control unit 505. If the data received from the base station 203 is control data, the control data is passed from the base station communication unit 502 to the control plane control unit 505.

[0099] The HeNBGW communication unit 504 transmits and receives data between the MME 204a and a HeNB GW (Home-eNB Gateway). Control data received by the HeNBGW communication unit 504 from the HeNB GW is passed to the control plane control unit 505. The HeNBGW communication unit 504 transmits the control data input from the control plane control unit 505 to the HeNB GW.

[0100] The control plane control unit 505 includes a NAS security unit 505-1, an SAE bearer control unit 505-2, an idle state mobility management unit 505-3, etc., and performs overall processing for the control plane (hereinafter sometimes referred to as the C-Plane). The NAS security unit 505-1 performs security for NAS (Non-Access Stratum) messages, etc. The SAE bearer control unit 505-2 performs management of SAE (System Architecture Evolution) bearers, etc. The idle state mobility management unit 505-3 performs mobility management in the idle state (also referred to as the LTE-IDLE state or simply idle), generation and control of paging signals in the idle state, addition, deletion, update, and search of tracking areas for one or more mobile terminals 202 under its control, tracking area list management, etc.

[0101] The MME 204a distributes paging signals to one or more base stations 203. The MME 204a also performs mobility control in an idle state. The MME 204a manages a tracking area list when the mobile terminal 202 is in an idle state and an active state. The MME 204a initiates a paging protocol by transmitting a paging message to cells belonging to a tracking area in which the mobile terminal 202 is registered. The idle state mobility management unit 505-3 may manage the CSG, CSG ID, and whitelist of the eNB 207 connected to the MME 204a.

[0102] A series of processes of MME 204a is controlled by control unit 506. Therefore, although not shown in Fig. 10, control unit 506 is connected to each of units 501 to 505. Similar to control unit 310 of mobile terminal 202 described above, control unit 506 is realized by a processing circuit including a processor and memory, or a dedicated processing circuit such as an FPGA, ASIC, or DSP.

[0103] FIG. 11 is a block diagram showing the configuration of a 5GC unit. FIG. 11 shows the configuration of the 5GC unit 214 shown in FIG. 3 described above. FIG. 11 shows a case where the 5GC unit 214 shown in FIG. 5 includes an AMF configuration, an SMF configuration, and a UPF configuration. 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 S1 interface between the 5GC unit 214 and the base station 203, and / or the NG interface between the 5GC unit 214 and the base station 213. If the data received from the Data Network is user data, the user data is passed from the Data Network communication unit 521 to the base station communication unit 522 via the user plane communication unit 523, and transmitted to one or more base stations 203 and / or base stations 213. If the data received from base station 203 and / or base station 213 is user data, the user data is passed from base station communication unit 522 to data network communication unit 521 via user plane communication unit 523 and transmitted to the data network.

[0104] If the data received from the Data Network is control data, the control data is passed 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 passes the control data to the control plane control unit 525. If the data received from the base station 203 and / or base station 213 is control data, the control data is passed from the base station communication unit 522 to the control plane control unit 525. The control plane control unit 525 passes the control data to the session management unit 527.

[0105] The control plane control unit 525 includes a NAS security unit 525-1, a PDU session control unit 525-2, an idle state mobility management unit 525-3, 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 PDU session control unit 525-2 performs management of PDU sessions between the mobile terminal 202 and the 5GC unit 214, etc. The idle state mobility management unit 525-3 performs mobility management in the idle state (idle state: also referred to as RRC_IDLE state or simply idle), generation and control of paging signals in the idle state, addition, deletion, update, and search of tracking areas for one or more mobile terminals 202 under its control, tracking area list management, etc.

[0106] A series of processes of the 5GC unit 214 is controlled by the control unit 526. Therefore, although the control unit 526 is omitted in Fig. 11, it is connected to each of the units 521 to 523, 525, and 527. Like the control unit 310 of the mobile terminal 202 described above, the control unit 526 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.

[0107] Next, an example of a cell search method in a communication system is shown. Fig. 12 is a flowchart showing an outline of the process from cell search to standby operation performed by a communication terminal (UE) in an LTE 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.

[0108] P-SS and S-SS are collectively called the Synchronization Signal (SS). The Synchronization Signal (SS) is assigned a synchronization code that corresponds one-to-one to the PCI assigned to each cell. 504 different PCIs are being considered. Communication terminals use these 504 different PCIs to synchronize and detect (identify) the PCI of the synchronized cell.

[0109] In step ST602, for the next synchronized cell, the communication terminal detects a cell-specific reference signal (CRS), which is a reference signal (RS) transmitted from the base station for each cell, and measures the RS received power (Reference Signal Received Power: RSRP). The RS uses a code that has a one-to-one correspondence with the PCI. By correlating with this code, the cell can be separated from other cells. By deriving the code for the RS of the cell from the PCI identified in step ST601, it becomes possible to detect the RS and measure the RS received power.

[0110] Next, in step ST603, the communication terminal selects the cell with the best RS reception quality, for example, the cell with the highest RS reception power, ie, the best cell, from among one or more cells detected up to step ST602.

[0111] Next, in step ST604, the communication terminal receives the PBCH of the best cell and obtains the BCCH, which is broadcast information. A MIB (Master Information Block), which includes 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 the DL (downlink) system bandwidth (also called transmission bandwidth configuration: dl-bandwidth), the number of transmitting antennas, and the SFN (System Frame Number).

[0112] Next, in step ST605, the communication terminal receives the DL-SCH of the cell based on the cell configuration information in the MIB, and obtains SIB (System Information Block) 1 in the broadcast information BCCH. SIB 1 includes information on access to the cell, information on cell selection, and scheduling information of other SIBs (SIBk; k is an integer greater than or equal to 2). SIB 1 also includes a tracking area code (TAC).

[0113] Next, in step ST606, the communication terminal compares the TAC of the SIB1 received in step ST605 with the TAC portion of the tracking area identity (TAI) in the tracking area list that the communication terminal already holds. 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.

[0114] 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, etc., to change the tracking area in order to perform a Tracking Area Update (TAU) through the cell.

[0115] In the example shown in Fig. 12, an example of operations from cell search to standby in the LTE system is shown, but in the NR system, in addition to the best cell, the best beam may be selected in step ST603. Also, in the NR system, beam information, for example, a beam identifier, may be acquired in step ST604. Also, in the NR system, scheduling information of remaining minimum SI (RMSI) may be acquired in step ST604. In the NR system, RMSI may be received in step ST605.

[0116] 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 (e.g., UE-ID) 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 operation in the cell.

[0117] The widespread use of smartphones and tablet devices has led to an explosive increase in cellular wireless communication traffic, raising concerns about a shortage of wireless resources worldwide. In response to this, efforts are being made to develop small cells and promote spatial separation in order to improve frequency utilization efficiency.

[0118] In a conventional cell configuration, a cell configured by an eNB has a relatively wide coverage area. Conventionally, a cell is configured so that a certain area is covered by the relatively wide coverage areas of multiple cells configured by multiple eNBs.

[0119] In the case of small cell configuration, a cell configured by an eNB has a narrower coverage area than a cell configured by a conventional eNB. Therefore, as in the past, a larger number of small cell configuration eNBs are required to cover a certain area compared to conventional eNBs.

[0120] In the following description, a cell with a relatively large coverage, such as a cell configured by a conventional eNB, is referred to as a "macro cell," and an eNB that configures the macro cell is referred to as a "macro eNB." Also, a cell with a relatively small coverage, such as a cell configured as a small cell, is referred to as a "small cell," and an eNB that configures the small cell is referred to as a "small eNB."

[0121] The macro eNB may be, for example, a "Wide Area Base Station" as described in Non-Patent Document 7.

[0122] The small eNB may be, for example, a low-power node, a local area node, a hotspot, etc. Also, the small eNB may be a pico eNB constituting a pico cell, a femto eNB constituting a femto cell, a HeNB, a remote radio head (RRH), a remote radio unit (RRU), a remote radio equipment (RRE), or a relay node (RN). Also, the small eNB may be a "local area base station" or a "home base station" as described in Non-Patent Document 7.

[0123] FIG. 13 shows an example of a cell configuration in NR. In an NR cell, narrow beams are formed and transmitted while changing direction. In the example shown in FIG. 13, at a certain time, base station 750 transmits and receives signals to and from a mobile terminal using beam 751-1. At another time, 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 configures a wide-area cell.

[0124] 13 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. 13, the number of beams used simultaneously by the base station 750 is 1, but it may be multiple.

[0125] 3GPP supports Side Link (SL) for D2D (Device to Device) communication and V2V (Vehicle to Vehicle) communication (see Non-Patent Document 1 and Non-Patent Document 16). SL is defined by the PC5 interface.

[0126] The physical channels used for SL (see Non-Patent Document 1) will be described below. A physical sidelink broadcast channel (PSBCH) carries information related to the system and synchronization, and is transmitted from a UE.

[0127] The physical sidelink discovery channel (PSDCH) carries sidelink discovery messages from the UE.

[0128] The physical sidelink control channel (PSCCH) carries control information from the UE for sidelink and V2X sidelink communications.

[0129] The physical sidelink shared channel (PSSCH) carries data from the UE for sidelink and V2X sidelink communications.

[0130] The physical sidelink feedback channel (PSFCH) carries HARQ feedback on the sidelink from UEs that receive a PSSCH transmission to the UE that transmitted the PSSCH.

[0131] The transport channel used for SL (see Non-Patent Document 1) will be described below. The sidelink broadcast channel (SL-BCH) has a predetermined transport format and is mapped to the PSBCH, which is a physical channel.

[0132] The Sidelink Discovery Channel (SL-DCH) has periodic broadcast transmissions of a fixed size and a predetermined format. The SL-DCH supports both UE autonomous resource selection and eNB-scheduled resource allocation. While UE autonomous resource selection involves a collision risk, there is no collision when the UE is allocated dedicated resources by the eNB. The SL-DCH supports HARQ combining but not HARQ feedback. The SL-DCH is mapped to the PSDCH, which is a physical channel.

[0133] The Sidelink Shared Channel (SL-SCH) supports broadcast transmission. It supports both UE autonomous resource selection and eNB-scheduled resource allocation. While UE autonomous resource selection carries a risk of collision, there is no collision when the UE is allocated dedicated resources by the eNB. The SL-SCH also supports HARQ combining but not HARQ feedback. The SL-SCH also supports dynamic link adaptation by varying transmit power, modulation, and coding. The SL-SCH is mapped to the PSSCH, a physical channel.

[0134] The logical channels used for SL (see Non-Patent Document 1) 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.

[0135] 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.

[0136] 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.

[0137] 3GPP is considering supporting V2X communication in NR as well. The study of V2X communication in NR is being carried out based on the LTE system and LTE-A system, but the following changes and additions have been made from the LTE system and LTE-A system.

[0138] In LTE, SL communication was limited to broadcast. In NR, support for unicast and groupcast as SL communication in addition to broadcast is being considered (see Non-Patent Document 22 (3GPP TS23.287)).

[0139] For unicast and groupcast communications, support for HARQ feedback (Ack / Nack), CSI reporting, etc. is being considered.

[0140] 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 22 (3GPP TS23.287)). For example, PC5-S signaling is implemented to establish a link for implementing SL, i.e., PC5 communication. This link is implemented in the V2X layer and is also called a Layer 2 link.

[0141] Furthermore, support for RRC signaling in SL communication is being considered (see Non-Patent Document 22 (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, and to notify AS layer settings for V2X communication using PC5 communication.

[0142] Positioning of a UE may be performed using positioning signal transmission and reception between a base station and the UE. The downlink positioning signal may be, for example, a Positioning Reference Signal (PRS), an SS block, a DM-RS, or a PTRS. The uplink positioning signal may be, for example, a Sounding Reference Signal (SRS), a PRACH, a DM-RS, or a PTRS. For example, the base station may transmit a downlink positioning signal to the UE. The UE may transmit an uplink positioning signal to the base station. Transmission of a downlink positioning signal from the base station and transmission of an uplink positioning signal from the UE may be performed independently. As another example, the UE may transmit an uplink positioning signal triggered by reception of a downlink positioning signal from the base station. As another example, the base station may transmit a downlink positioning signal triggered by reception of an uplink positioning signal from the UE.

[0143] The UE may notify the LMF of the reception result of the downlink positioning signal. The reception result of the downlink positioning signal may include, for example, information about the propagation delay of the downlink positioning signal or information about the arrival direction of the downlink positioning signal. As another example, the UE may transmit to the LMF information about the time difference between receiving the downlink positioning signal and transmitting the uplink positioning signal, information about the transmission time of the uplink positioning signal, or information about the reception time of the downlink positioning signal.

[0144] The base station may notify the LMF of the reception result of the uplink positioning signal. The reception result of the uplink positioning signal may include, for example, information about the propagation delay of the uplink positioning signal or information about the arrival direction of the uplink positioning signal. As another example, the base station may notify the LMF of information about the transmission time of the downlink positioning signal, may transmit information about the reception time of the uplink positioning signal, or may transmit information about the time difference between the reception of the uplink positioning signal and the transmission of the downlink positioning signal.

[0145] The LMF may use the above information from the UE and / or the base station to derive the location of the UE.

[0146] In locating a UE, the base station may be stationary or moving.

[0147] In the above, the following problem occurs: In UE positioning, information about the relative position of the UE with respect to the base station is used, and therefore, a problem occurs in that an error occurs in the UE positioning result when the base station moves.

[0148] In the first embodiment, a solution to the above-mentioned problem will be disclosed.

[0149] The base station notifies the LMF of its location and time information. The base station may send this information to the LMF once or multiple times.

[0150] The base station may notify the LMF of information associating its own location with time information. The LMF may use this information to calculate the UE's location. This allows the LMF to accurately calculate the UE's location, for example, since the base station's location at that time is known.

[0151] The following (1) to (12) are disclosed as examples of information that the base station notifies the LMF.

[0152] (1) Information that identifies the base station.

[0153] (2) Information about the location of base stations.

[0154] (3) Information regarding the reception results of positioning signals.

[0155] (4) Information about time.

[0156] (5) Information about base station speed.

[0157] (6) Information about the acceleration of the base station.

[0158] (7) Information about positioning methods.

[0159] (8) Information regarding the validity period of the notification content.

[0160] (9) Information about the UE to be positioned.

[0161] (10) Information about DU similar to (1) to (8) above or a combination thereof.

[0162] (11) Information related to TRPs similar to (1) to (8) above or a combination thereof.

[0163] (12) A combination of (1) to (11) above.

[0164] The information (1) above may be, for example, a base station identifier. The identifier information may be, for example, a gNB-ID. The LMF may use the information to identify the base station that sent the notification. This allows, for example, the LMF to easily identify the base station that sent the notification, thereby enabling the positioning procedure in the communication system to be performed quickly.

[0165] The information (2) above may include, for example, information indicating the location of the base station. The information indicating the location of the base station may be, for example, information indicating latitude, longitude, and / or altitude, or information indicating a relative location from a predetermined point. This allows, for example, the LMF to reduce errors in calculating the location of the UE.

[0166] The information (2) above may include information about the accuracy of the base station's location. For example, the accuracy information may be provided regardless of the coordinate axis, or may be provided for each coordinate axis. For example, accuracy may be provided for each of latitude, longitude, and altitude, or accuracy in the horizontal direction (i.e., latitude and longitude direction) and accuracy in the vertical direction (i.e., altitude direction) may be provided. This allows, for example, the LMF to derive the accuracy in calculating the UE's location.

[0167] The information (2) above may include, for example, information about the zone disclosed in Non-Patent Document 33 (3GPP TR37.985). The information about the zone may be one or more pieces of information. The LMF may use the information to change the base station used for positioning. For example, the LMF may set the base station used for UE positioning to a base station belonging to the same zone. This makes it possible to prevent the range in which the base stations used for positioning are located from being unnecessarily large, thereby improving the positioning accuracy.

[0168] The LMF may reallocate zones to the base station using information indicating the base station's location and information indicating the zones. The LMF may notify the base station of information about the reallocated zones. The base station may use this information to update the zone information of its own base station. This makes it possible to reduce interference with other UEs in sidelink communication performed by UEs under the base station.

[0169] The information (3) above may include information about the propagation delay of the positioning signal, information about the accuracy of the propagation delay, information about the angle of arrival of the positioning signal, information about the accuracy of the angle of arrival, or a combination of the above information, which allows the LMF to quickly derive the location of the UE, for example.

[0170] The information (4) above may include, for example, information on the time when the base station position is derived, information on the accuracy of the time, information on the time when a positioning signal is transmitted to the UE, information on the accuracy of the time, information on the time when a positioning signal is received from the UE, information on the accuracy of the time, or a combination of the above information. The LMF may use the information to derive the UE position at a certain time. For example, the LMF may derive the UE position using a combination of times when the time when the base station position is derived, the time when a positioning signal is transmitted to the UE, and the time when a positioning signal is received from the UE are close to each other. This allows the LMF to improve the accuracy of deriving the UE position, for example.

[0171] The information in (5) above may be, for example, the one-dimensional speed of the base station, the horizontal and vertical speeds, or the latitude, longitude, and / or altitude speeds. The LMF may use this information to calculate the UE's location. This may enable the LMF to improve the accuracy of deriving the UE's location, for example.

[0172] The information in (6) above may be, for example, the absolute value of the acceleration of the base station, the acceleration in each of the horizontal and vertical directions, or the acceleration in the latitude, longitude, and / or altitude directions. The LMF may use this information to calculate the position of the UE. This may enable the LMF to improve the accuracy of deriving the position of the UE, for example.

[0173] The information (7) above may be, for example, information indicating a positioning method using radio waves of a communication system. The positioning method may be, for example, Observed Time Difference Of Arrival (OTDOA), Enhanced Cell ID (E-CID), NR E-CID, Multi-RTT using round-trip times (RTT) between each of multiple base stations and the UE, Downlink Angle of Departure (DL-AoD), Downlink Time Difference Of Arrival (DL-TDOA), Uplink Time Difference Of Arrival (UL-TDOA), or Uplink Angle of Arrival (UL-AoA), as disclosed in Non-Patent Document 24 (3GPP TS38.305). As another example, the information in (7) above may be positioning using a Global Navigation Satellite System (GNSS), positioning using a barometric pressure sensor, positioning using a Wireless Local Area Network (WLAN), positioning using Bluetooth (registered trademark), or positioning using a Terrestrial Beacon System. The LMF may use the information to acquire information about a positioning method for the UE. This allows the LMF to quickly acquire information about a positioning method for the UE, and as a result, the LMF can quickly perform positioning of the UE.

[0174] The information (8) above may be information indicating the validity period of notification from the base station to the LMF. The validity period may be determined, for example, using requirements for UE positioning (e.g., accuracy) or the speed of the base station. The LMF may use the information to obtain the period during which information regarding the base station's location, etc. is valid. When the validity period expires, the LMF may request the base station to notify information such as the location. When the validity period expires, the base station may again notify the LMF. This may, for example, improve the UE's positioning accuracy.

[0175] The information (9) above may be information about the identifier of the UE to be positioned. The information about the identifier may be, for example, a UE-ID, or a Subscription Permanent Identifier (SUPI), Subscription Concealed Identifier (SUCI), Permanent Equipment Identifier (PEI), and / or 5G Globally Unique Temporary Identifier (5G-GUTI) disclosed in Non-Patent Document 21 (3GPP TS23.501). The LMF may use the information to identify the UE. This allows the LMF to quickly identify the UE, for example, even when positioning of multiple UEs is being performed.

[0176] The information in (10) above may be, for example, information in which the base station in the above (1) to (8) is replaced with DU. The information in (10) above may be one piece, or may include multiple pieces, for example, the number of pieces equal to the number of DUs. This makes it possible to improve the positioning accuracy of UEs, for example, even in a communication system using a base station configured separately as a CU and a DU.

[0177] The information in (11) above may be, for example, information in which the base station in (1) to (8) above is replaced with TRP. The information in (11) above may be one piece, or may include multiple pieces, for example, the number of pieces equal to the number of TRPs. This makes it possible to improve the positioning accuracy of UEs, for example, even in a communication system using a base station having a TRP.

[0178] The information associating the base station location with the time information may be included in the assistance data notification from the gNB to the LMF, as disclosed in Non-Patent Document 24 (3GPP TS38.305). For example, the assistance data notification may include the information in (4) above. This makes it possible to reduce the amount of signaling between the base station and the LMF, for example.

[0179] As another example, the information may be included in the notification of uplink information / UE configuration data disclosed in Non-Patent Document 24 (3GPP TS38.305). For example, the notification may include the information (2) and (4) described above. This may provide, for example, the same effects as those described above.

[0180] As another example, the information may be included in the notification of the positioning signal reception result disclosed in Non-Patent Document 24 (3GPP TS38.305). For example, the notification may include the information (2) and (4) described above. The information (4) may be, for example, information on the time when the position of the base station was acquired. This may provide, for example, the same effect as described above.

[0181] As another example, new signaling may be provided for transmitting the information, such as a TRP information update, which may ensure backward compatibility in the communication system.

[0182] The base station may notify information associating its own position with time information only once. A single notification may include only one piece of the associated information, or multiple pieces of the associated information. In an example where multiple pieces of information are included, the time range included in the multiple pieces of information may include the time of transmission and reception of the positioning signal. This allows, for example, the LMF to apply interpolation processing rather than extrapolation processing to derive the position of the base station and / or UE, thereby improving the accuracy of position calculation. In another example where multiple pieces of information are included, the time range included in the multiple pieces of information may not include the time of transmission and reception of the positioning signal. For example, the end point of the range may be before the end point of the time of transmission and reception of the positioning signal. This, for example, makes it possible to reduce delays in positioning.

[0183] As another example, the base station may notify information associating its own position with time information multiple times. The multiple notifications may be performed, for example, by specifying the number of times, or may be performed without specifying the number of times. The multiple notifications may be performed periodically, for example. Information regarding the number of times and / or the periodicity may be predetermined in a standard, determined by the LMF, determined by the AMF, or determined by the base station. The LMF and / or AMF may notify the base station of the information. For example, the LMF may notify the base station of the information using LPP signaling and / or NRPPa signaling. The AMF may notify the base station of the information using NAS signaling. The base station may start the periodic notification before transmitting / receiving a positioning signal, may start the notification in response to a positioning signal transmission / reception start instruction from the LMF, or may start the notification after receiving an uplink positioning signal transmission instruction to the UE. The base station may terminate the periodic notification when the transmission and reception of the positioning signal with the UE is completed, or when the base station notifies the LMF of the result of the transmission and reception of the positioning signal. This may improve the accuracy of the UE positioning, for example.

[0184] As another example of multiple notification of the information, the base station may notify the LMF again when the validity period of the notification to the LMF expires, or when the distance between the location included in the previous notification and the current location of the base station exceeds a predetermined value. The predetermined value may be determined, for example, using a requirement (e.g., accuracy) for UE positioning. This may, for example, improve the accuracy of UE positioning.

[0185] As another example of multiple notification of the information, the base station may perform the notification in response to a predetermined event. For example, the base station may perform the notification in response to a positioning signal transmission / reception start instruction from the LMF, an uplink positioning signal transmission instruction to the UE, completion of positioning signal transmission / reception with the UE, or notification of the positioning signal transmission / reception result to the LMF, or any combination of the above. This may reduce the amount of signaling between the base station and the LMF, for example.

[0186] The base station may autonomously notify the LMF of the information. For example, the base station may notify the LMF in response to a predetermined event. The predetermined event may be, for example, reception of a positioning signal transmission / reception start instruction from the LMF, transmission of an uplink positioning signal transmission instruction to the UE, completion of positioning signal transmission / reception with the UE, transmission of a positioning signal transmission / reception result notification to the LMF, or a combination of the above. This may, for example, reduce the amount of signaling between the base station and the LMF.

[0187] As another example of the notification of the information from the base station to the LMF, the LMF may request the base station to notify the information. The base station may notify the information to the LMF in response to the request.

[0188] The LMF may request the base station to start notifying the information or to stop notifying the information. The base station may start notifying the information or stop notifying the information in response to the request. This may, for example, avoid complexity in the communication system.

[0189] As another example of the request, the LMF may request the base station to notify multiple pieces of the information. The notification of multiple pieces of the information from the base station to the LMF may be performed at once. This may reduce the amount of signaling between the base station and the LMF, for example. As another example, the notification from the base station to the LMF may be performed multiple times. The notification may be performed periodically.

[0190] The following (A) to (J) are disclosed as examples of information included in the request from the LMF to the base station.

[0191] (A) Start request.

[0192] (B) Request for suspension.

[0193] (C) Information specifying a time.

[0194] (D) Information regarding notification cycles.

[0195] (E) Information regarding the number of notifications.

[0196] (F) Information regarding the number of pieces of information included in the notification, for example, the number of pieces of information including the combination of the base station location and time included in one notification.

[0197] (G) Information about positioning methods.

[0198] (H) Information regarding the content of the notification.

[0199] (I) Information regarding positioning requirements.

[0200] (J) A combination of (A) to (I) above.

[0201] The base station may initiate a notification to the LMF using the information on (A) above, which may avoid, for example, the complexity of the design related to the processing for initiating the notification in the base station.

[0202] The base station may stop the notification to the LMF using the information on (B) above, which may avoid, for example, the complexity of the design related to the processing for stopping the notification in the base station.

[0203] The information shown in (C) above may be, for example, information indicating the range of time information notified from the base station to the LMF. The time information may be, for example, the information disclosed as (4) of the information notified from the base station to the LMF. The information shown in (C) above may include information indicating the start point of the range of time information, information indicating the end point, or information indicating the duration of the range. The base station may use the information shown in (C) above to determine the information to be included in the notification to the LMF. This makes it possible to prevent, for example, excess or deficiency of information in the notification from the base station to the LMF.

[0204] The information shown in (D) above may include, for example, the period of the notification from the base station to the LMF, or may include information on an offset to the period, or may include both of the above. The offset may be given, for example, as a remainder of the time at which the base station transmits the notification modulo the period, or may be given as information on a certain transmission time. The offset may be given as information using time, or as information using a radio frame number, a subframe number, a slot number, and / or a symbol number. The base station may use this information to send the notification to the LMF. This, for example, enables the LMF to track changes in the base station's location, thereby enabling quick calculation of the UE's location.

[0205] The information shown in the above (E) may be transmitted once or multiple times. For example, the LMF may set the above-mentioned (E) to a small value, thereby reducing the amount of signaling between the base station and the LMF. As another example, the LMF may set the above-mentioned (E) to a large value, thereby enabling the base station position to be calculated with high accuracy, thereby improving the positioning accuracy of the UE position.

[0206] The information indicated in (F) above may be, for example, the number of pieces of information about the location included in one notification from the base station to the LMF. The value of this information may be 1, or 2 or more. For example, the LMF can reduce the processing load in the base station by setting the value of (F) above to a small value. As another example, the LMF can calculate the position of the base station at a certain time with high accuracy by setting the value of (F) above to a large value, which results in improved positioning accuracy of the UE position.

[0207] The information shown in (G) above may include, for example, information about the positioning method that the LMF requests the base station to use. The information about the positioning method may be similar to the information disclosed as (7) of the information that the base station notifies the LMF to, as described above. This may, for example, improve the flexibility of the communication system.

[0208] The information shown in the above (H) may be, for example, the information (1) to (12) disclosed above as examples of information that the base station notifies the LMF. The base station may derive the information to be notified to the LMF using the information in the above (H). This makes it possible to reduce, for example, the amount of signaling between the base station and the LMF, and also to reduce the amount of processing in the base station.

[0209] The information shown in the above (I) may be, for example, information about the latency of positioning or information about the accuracy of positioning. The base station may, for example, use the information about the accuracy of positioning to determine whether to resubmit notification to the LMF. For example, if the base station has moved by more than a predetermined value from the position at the time of the previous notification, the base station may resubmit notification to the LMF. The predetermined value may, for example, be determined using the accuracy requirement included in the above (I). This may, for example, improve the accuracy of UE positioning.

[0210] The information from the LMF to the base station may be included in the signaling of the assistance data request from the LMF to the gNB (e.g., TRP information request) disclosed in Non-Patent Document 24 (3GPP TS38.305). This makes it possible to reduce the amount of signaling between the base station and the LMF, for example.

[0211] As another example, the information may be included in the signaling of a UL SRS setting request (e.g., a positioning information request) disclosed in Non-Patent Document 24 (3GPP TS38.305), which can provide, for example, the same effect as described above.

[0212] As another example, the information may be included in signaling of a positioning signal transmission / reception request (e.g., Measurement request) disclosed in Non-Patent Document 24 (3GPP TS38.305). This can provide, for example, the same effect as described above.

[0213] Alternatively, new signaling may be provided to transmit the information, which may allow, for example, backward compatibility in communication systems.

[0214] Next, a method for locating a UE in the communication system according to the first embodiment will be described.

[0215] Fig. 14 is a sequence diagram showing an example of a UE positioning sequence in which a base station notifies an LMF of a combination of its own base station's position and time information. Fig. 14 shows a case where multi-RTT is used as the positioning method. In the example of the positioning sequence shown in Fig. 14, the base station periodically notifies the LMF of information on a combination of its own base station's position and time information. Fig. 14 shows an example of a sequence in which the base station's upper device has a positioning function for deriving the UE's position, that is, an example of a sequence in which the upper device operates as a positioning execution device.

[0216] In step ST1403 shown in FIG. 14, the AMF requests the LMF for a positioning service. The request may be, for example, a request related to measuring the UE location. The AMF may make the request in response to a request from a Location Service (LCS) client outside the 5G system, in response to a request from the UE, or in response to an autonomous request by the AMF.

[0217] The request from the LCS, UE, and / or AMF outside the 5G system may include a request for information about the location of a base station to which the UE is connected. The AMF may request information about the location of the base station from the LMF. This allows, for example, the LCS to quickly determine the location of the base station to which the UE is connected and to quickly perform processing in location-based services.

[0218] An NWDAF (Network Data Analytics Function) disclosed in Non-Patent Document 21 (3GPP TS23.501) may request information on the locations of UEs and / or base stations from an LMF. The request may be made via an AMF. The AMF may perform the process of step ST1403 in response to the request from the NWDAF. This enables, for example, the NWDAF to process the location information, thereby reducing the amount of processing by other devices in the communication network apparatus.

[0219] In procedure 1405 shown in FIG. 14, downlink PRS configuration information is exchanged between the LMF and the serving base station. The signaling in procedure 1405 may be, for example, NRPPa signaling. In Step ST1407, the LMF requests TRP information from the serving base station. In Step ST1409, the serving base station notifies the LMF of the TRP information. Step ST1409 may include information regarding the identifiers of the cell, DU, and / or TRP (hereinafter, may be referred to as cells, etc.) of the serving base station, information regarding the timing of the cell, etc. (e.g., frame timing), information regarding the PRS configuration of the cell, etc., information regarding the SS block and SS burst of the cell, etc. (e.g., information regarding frequency and / or time resource), information regarding the PRS transmission direction from the cell, etc., or information regarding the location of the cell, etc.

[0220] In procedure 1410 shown in FIG. 14, the same processing as in procedure 1405 is performed between the LMF and the neighboring base station.

[0221] In step ST1415 shown in FIG. 14, the serving base station and / or the peripheral base station notifies the LMF of the location and / or time information of the own base station. For example, NRPPa signaling may be used for the notification in step ST1415. The information transmitted in step ST1415 may include the above-mentioned (1) to (12) disclosed as examples of information that the base station notifies the LMF. The transmission in step ST1415 may be performed repeatedly. The LMF uses step ST1415 to obtain information related to the location of the serving base station and / or the peripheral base station. In the example shown in FIG. 14, the serving base station and / or the peripheral base station start the notification in step ST1415 triggered by procedure 1405 and / or procedure 1410.

[0222] In procedure 1420 shown in Fig. 14, a request for and notification of positioning-related capabilities are made between the LMF and the UE. The signaling in procedure 1420 may be, for example, LPP signaling. In Step ST1423, the LMF requests the UE for positioning-related capabilities. In Step ST1425, the UE notifies the LMF of the positioning-related capabilities.

[0223] In Step ST1427 shown in FIG. 14, the LMF requests positioning information from the serving base station. This request may include an uplink positioning signal, for example, a request to configure an uplink SRS. In Step ST1430, the serving base station determines the uplink SRS resources for the UE. In Step ST1433, the serving base station configures the uplink SRS for the UE. In Step ST1435, the serving base station transmits a response to the positioning information request to the LMF. This response may include information regarding the SRS configuration of the UE, for example, information regarding the time and / or frequency resources of the SRS.

[0224] In Step ST1436 shown in FIG. 14, the LMF requests the serving base station to activate SRS transmission of the UE. In Step ST1437, the serving base station requests the UE to activate SRS transmission. Step ST1437 triggers the UE to start transmitting SRS.

[0225] In step ST1440 shown in FIG. 14, the LMF requests the serving base station and / or neighboring base stations to measure the positioning signal. For example, NRPPa signaling may be used for the request. For example, the NRPPa MEASUREMENT REQUEST disclosed in Non-Patent Document 24 (3GPP TS38.305) may be used for the NRPPa signaling.

[0226] In step ST1443 shown in FIG. 14, the LMF notifies the UE of information used for positioning. The information may be, for example, information about the downlink PRS of the serving base station and / or neighboring base stations, information about frame timing, or a combination of the above. For example, LPP signaling may be used to notify the information. The LPP signaling may be, for example, LPP Provide Assistance Data disclosed in Non-Patent Document 24 (3GPP TS38.305).

[0227] In step ST1445 shown in Fig. 14, the LMF requests the UE to perform positioning. For example, LPP signaling may be used for this request. For example, the LPP signaling may be LPP Request Location Information disclosed in Non-Patent Document 24 (3GPP TS38.305). The UE performs measurement processing of the PRS in accordance with this request.

[0228] In Step ST1447 shown in FIG. 14, the UE requests the serving base station to set a measurement gap for transmitting and receiving a positioning signal. For this request, RRC signaling, for example, the RRC Location Measurement Indication disclosed in Non-Patent Document 24 (3GPP TS38.305), may be used. The request may include information regarding the start of a measurement gap for positioning. In Step ST1449, the serving base station instructs the UE to set a measurement gap. The UE sets a measurement gap in accordance with the instruction in Step ST1449.

[0229] In Step ST1451 and Step ST1453 shown in Fig. 14, the serving base station and the neighboring base station each transmit a PRS to the UE. In Step ST1455, the UE performs a process of receiving the PRS from the serving base station and / or the neighboring base station. This reception process includes a process of measuring the PRS.

[0230] In Step ST1457 shown in Fig. 14, the UE transmits the SRS to the serving base station. In Step ST1459, the serving base station performs a process of receiving the SRS from the UE. This receiving process includes a process of measuring the SRS.

[0231] 14, the UE transmits an SRS to a neighboring base station. In Step ST1463, the neighboring base station performs a process of receiving the SRS from the UE. This process of receiving the SRS includes a process of measuring the SRS.

[0232] In step ST1465 shown in FIG. 14, the UE notifies the LMF of information related to the reception result of the positioning signal. For example, LPP signaling may be used for this notification. The LPP signaling may be, for example, LPP Provide Location Information disclosed in Non-Patent Document 24 (3GPP TS38.305).

[0233] In step ST1467 shown in FIG. 14, the serving base station and / or the neighboring base station notifies the LMF of information related to the reception result of the positioning signal. For example, NRPPa signaling may be used for this notification. For example, the NRPPa signaling may use the NRPPa MEASUREMENT RESPONSE disclosed in Non-Patent Document 24 (3GPP TS38.305).

[0234] In Step ST1469 shown in FIG. 14, the UE requests the serving base station to change the measurement gap. The request may be a request to restore the measurement gap to the setting before positioning. RRC signaling, for example, RRC Location Measurement Indication disclosed in Non-Patent Document 24 (3GPP TS38.305), may be used for the request. The request may include information regarding the suspension of the measurement gap for positioning. In Step ST1471, the serving base station instructs the UE to set the measurement gap. The UE changes the measurement gap setting in accordance with the instruction in Step ST1471.

[0235] In step ST1475 shown in FIG. 14, the serving base station and / or the peripheral base station transmits the position and / or time information of the own base station to the LMF. The information transmitted in step ST1475 may be the same as that in step ST1415. The LMF uses step ST1475 to obtain information related to the positions of the serving base station and / or the peripheral base station. In the example shown in FIG. 14, the serving base station and / or the peripheral base station may end the periodic transmission shown in step ST1475 upon receiving notification of information related to the reception result of the positioning signal shown in step ST1467. For example, the signaling of step ST1467 transmitted after step ST1467 may be the final transmission process. This makes it possible to reduce, for example, the amount of signaling between the base station and the LMF.

[0236] In step ST1479 shown in Fig. 14, the LMF calculates the location of the UE. The LMF may use the information in step ST1415, step ST1465, step ST1467, and / or step ST1475 to calculate the location of the UE.

[0237] 14, the LMF notifies the AMF of information related to the calculated UE location. The AMF may notify the UE of the information, may notify an LCS outside the 5G system, or may use the information in its own AMF.

[0238] Step ST1481 shown in Fig. 14 may include information about the location of the base station and / or the time. The AMF may notify the UE of the information about the location of the base station and / or the time, may notify an LCS outside the 5G system, or may use the information in its own AMF. This enables, for example, the AMF to appropriately specify an RNA and / or a tracking area for a moving base station.

[0239] The LMF may notify the NWDAF of information regarding the location of the UE and / or base station. The notification may be performed via the AMF. The LMF may notify the NWDAF when the NWDAF requests the information. The NWDAF may use the information to perform data processing related to the location information. This may, for example, reduce the amount of data processing required by other devices in the communication network.

[0240] 14 shows an example in which the serving base station and / or the neighboring base station starts the notification of step ST1415 with procedure 1405 and / or procedure 1410 as a trigger, but the notification may be started with another process, for example, with a request for measurement of the positioning signal as shown in step ST1440 as a trigger. This makes it unnecessary to perform the process of step ST1415 before the request for measurement of the positioning signal, for example, and as a result, it is possible to reduce the amount of signaling between the LMF and the base station.

[0241] 14, the serving base station and / or the neighboring base station may perform the processing of step ST1415 and / or step ST1475 for the LMF simultaneously from each base station or may perform the processing at different times. By performing the processing at different times, for example, it is possible to level the signaling load on the interface between the LMF and the base station.

[0242] Fig. 15 is a sequence diagram showing another example of a UE positioning sequence in which a base station notifies an LMF of a combination of its own base station's location and time information. Fig. 15 shows a case in which multi-RTT is used as the positioning method. Fig. 15 shows an example in which the base station notifies information on a combination of its own base station's location and time information in response to a request from the LMF. In Fig. 15, the same steps as in Fig. 14 are assigned the same step numbers, and common explanations will be omitted.

[0243] Steps ST1403 to ST1437 shown in FIG. 15 are the same as those in FIG.

[0244] In step ST1538 shown in FIG. 15, the LMF requests information about the location and / or time of the base station from the serving base station and / or neighboring base stations. The request may be made using NRPPa signaling. The request may include the above-disclosed information (A) to (J) included in the request from the LMF to the base station.

[0245] In step ST1539 shown in FIG. 15, the serving base station and / or the peripheral base station notifies the LMF of the location and / or time information of the own base station. For example, NRPPa signaling may be used for the notification in step ST1539. The information transmitted in step ST1539 may include the above-mentioned (1) to (12) disclosed as examples of information that the base station notifies the LMF. The LMF uses step ST1539 to obtain information related to the location of the serving base station and / or the peripheral base station.

[0246] Steps ST1440 to ST1471 in FIG. 15 are the same as those in FIG.

[0247] Steps ST1573 and ST1574 in FIG. 15 are the same as steps ST1538 and ST1539, respectively.

[0248] Steps ST1479 to ST1481 in FIG. 15 are the same as those in FIG.

[0249] The UE may notify the LMF of information that combines the downlink positioning signal reception result and time information. The time information may be, for example, information about the time when the UE received the downlink positioning signal. The UE may transmit a plurality of pieces of the combined information. The notification may be performed via the base station and / or the AMF. The LMF may use the information to derive the location of the UE. This may, for example, improve the positioning accuracy of the UE.

[0250] The LMF may calculate the position of the UE using the combined information notified by the base station. For example, the LMF may calculate the position of the base station at the time when a positioning signal is transmitted and received between the UE and the base station. The LMF may use information about the speed of the base station or information about the acceleration of the base station to calculate the position of the base station. As another example, the LMF may calculate the speed and / or acceleration of the base station. The LMF may calculate the position of the UE using the information about the position, speed, and / or acceleration of the base station calculated as described above. This may, for example, improve the accuracy of the calculation of the position of the UE.

[0251] The LMF may notify the AMF of the UE location calculation result. The AMF may notify the information to a device having a location service function. The device may be, for example, a UE or a device located in a network outside the 5G network. This enables processing using the UE location information in, for example, a system including a communication system.

[0252] The base station may signal to the LMF via the AMF, and the LMF may signal to the base station via the AMF, which may avoid, for example, complexity in the interface between the base station and the LMF.

[0253] According to the first embodiment, it is possible to improve the accuracy of UE positioning when the base station is moving.

[0254] Variation 1 of Embodiment 1 In the above-mentioned first embodiment, a method for locating a UE when an LMF exists in 5GC has been described, but when a base station has an LMF, the method disclosed in the first embodiment may be used. The LMF held by the serving base station may acquire information about the position and time of the own base station. A neighboring base station may notify the serving base station of information about the position and time of the own base station.

[0255] FIG. 16 is a sequence diagram showing an operation in which a neighboring base station notifies a serving base station of a combination of the base station's position and time information in a UE positioning sequence when the base station has an LMF. FIG. 16 shows a case where multi-RTT is used as the positioning method. FIG. 16 shows an example of a sequence when the base station has a positioning function for deriving the UE's position, that is, an example of a sequence when the base station operates as a positioning execution device. In the example of the positioning sequence shown in FIG. 16, the neighboring base station periodically notifies the serving base station of this information. In FIG. 16, the same steps as in FIG. 14 are assigned the same step numbers, and detailed descriptions of these processes will be omitted.

[0256] In FIG. 16, the processing with the same step numbers as in FIG. 14 is processing in which the LMF in each step in FIG. 14 is replaced with the serving base station.

[0257] In FIG. 16, the UE may perform Step ST1403. For example, the UE may request a positioning service from a serving base station. This makes it possible to quickly request a positioning service from a serving base station having an LMF, for example. The UE may notify the AMF that the processing of Step ST1403 has been performed. The serving base station may notify the AMF. This makes it possible for the AMF to know that a positioning service request has been made to the LMF, and as a result, it is possible to prevent duplicate positioning services from being performed.

[0258] In FIG. 16, the serving base station may perform step ST1481 for the UE. This operation may be performed, for example, when the UE makes a request for a positioning service. This enables, for example, a serving base station having an LMF to quickly notify the UE of a positioning result. The serving base station may notify the AMF that the processing of step ST1481 has been performed. This enables, for example, the AMF to know that positioning has been completed. As a result, it is possible to prevent unnecessary processing wait time from occurring in processing related to positioning.

[0259] As another example, a peripheral base station may notify the serving base station of a combination of its own base station's location and time information, triggered by a request from the serving base station. For example, in steps ST1538, ST1539, ST1573, and ST1574 in Fig. 15, processing may be performed in which LMF is replaced with serving base station. This makes it possible to reduce, for example, the amount of signaling between the serving base station and the peripheral base stations.

[0260] According to this first modification, even when the serving base station has an LMF and the base station is moving, it is possible to calculate the position of the base station at a certain time, thereby improving the positioning accuracy of the UE.

[0261] Variation 2 of Embodiment 1 In the above-mentioned first embodiment, a method for UE positioning when an LMF exists in 5GC has been described, but the method disclosed in the first embodiment may also be used when the UE has an LMF. The LMF held by the UE may acquire information regarding the position and time of the serving base station and / or surrounding base stations. The surrounding base station may notify the UE of information regarding the position and time of its own base station via the serving base station. The serving base station may notify the UE of the information regarding its own base station and / or surrounding base stations.

[0262] FIG. 17 is a sequence diagram showing an operation in which a serving base station notifies a UE of a combination of location and time information at the own base station and neighboring base stations in a UE positioning sequence when the UE has an LMF. FIG. 17 shows a case where multi-RTT is used as the positioning method. FIG. 17 shows an example of a sequence when the UE has a positioning function for deriving the UE's location, that is, an example of a sequence when the UE operates as a positioning device. In the example of the positioning sequence shown in FIG. 17, the serving base station periodically notifies the UE of this information. In FIG. 17, the same steps as in FIG. 14 are assigned the same step numbers, and detailed descriptions of these processes will be omitted.

[0263] In FIG. 17, the processes with the same step numbers as those in FIG. 14 are processes in which LMF in each step in FIG. 14 is replaced with UE.

[0264] In step ST1714 shown in FIG. 17, the neighboring base station notifies the serving base station of the location and / or time information of its own base station. For example, NRPPa signaling may be used for the notification in step ST1714. The information transmitted in step ST1714 may include the above-mentioned (1) to (12) disclosed as examples of information that the base station notifies the LMF. The transmission in step ST1714 may be performed repeatedly.

[0265] In step ST1715 shown in FIG. 17, the serving base station notifies the UE of the location and / or time information of its own base station and / or neighboring base stations. For example, NRPPa signaling may be used for the notification in step ST1715. The information transmitted in step ST1715 may include the above-mentioned (1) to (12) disclosed as examples of information that the base station notifies the LMF. Step ST1715 may be performed repeatedly. The transmission of step ST1715 may be triggered by step ST1714 or may be performed independently of step ST1714.

[0266] Steps ST1774 and ST1775 shown in FIG. 17 are similar to steps ST1714 and ST1715, respectively.

[0267] In FIG. 17, step ST1403 may be performed inside the UE. For example, the UE may not transmit step ST1403 to other devices. This operation may be performed, for example, when the UE makes a request for a positioning service. This enables, for example, the UE to quickly request a positioning service to its own UE having an LMF. The UE may notify the AMF that the processing of step ST1403 has been performed. This enables, for example, the AMF to know that a request for a positioning service has been made to the LMF, and as a result, it becomes possible to prevent duplicate positioning services from being performed.

[0268] In FIG. 17, the UE may perform step ST1481 within the UE itself. For example, the UE may not transmit step ST1481 to other devices. This operation may be performed, for example, when the UE makes a request for a positioning service. This enables, for example, a UE having an LMF to quickly notify its own UE of a positioning result. The UE may notify the AMF that the processing of step ST1481 has been performed. This enables, for example, the AMF to know that positioning has been completed. As a result, it is possible to prevent unnecessary processing waiting time from occurring in processing related to positioning.

[0269] As another example, a request from the UE may trigger a notification from a neighboring base station to a serving base station and / or from the serving base station to a UE of a combination of the location and time information of the base station and / or neighboring base stations. Furthermore, a request from the UE may trigger a notification from a neighboring base station to a serving base station of a combination of the location and time information of the base station and / or neighboring base stations. The UE may request notification of the combination from the serving base station. The serving base station may request notification of the combination from the neighboring base station. A request from the serving base station may trigger a notification from the neighboring base station of the combination of the base station. The serving base station may then notify the UE of the combination of the base station and / or neighboring base stations. This may reduce the amount of signaling, for example, between the UE and the serving base station, and between the serving base station and the neighboring base station.

[0270] According to the present modification 2, even when the serving base station has a UE and the base station is moving, it is possible to calculate the position of the base station at a certain time, and as a result, it is possible to improve the positioning accuracy of the UE.

[0271] Embodiment 2 As described above, a 5G base station can be configured to be divided into a central unit (CU) and distributed units (DUs). In this embodiment, a case will be described in which UE positioning is performed using a base station having a configuration in which the CU and DU are separated. In this positioning, a positioning signal may be transmitted and received between the UE and the DU. The CU may notify the LMF of information regarding the location of the DU.

[0272] The above-described configuration has the following problem. That is, the CU needs to know the location of the DU. However, the methods by which the CU acquires the location of the DU are not disclosed in the standards and the like that have been established so far, including the above-mentioned Non-Patent Documents 1 to 33. As a result, for example, when the DU moves, the CU cannot know the location of the DU, which causes a problem of a deterioration in the accuracy of UE positioning or even the impossibility of positioning.

[0273] Therefore, this embodiment discloses a method for solving the above-mentioned problem. That is, in the communication system according to this embodiment, the DU notifies the CU of information about the location of the DU itself. This information may include information about time information. The time information may be, for example, information about the time when the DU obtained the location information of the DU itself.

[0274] The notification from the DU to the CU may be performed using F1 signaling. The F1 signaling may be, for example, the signaling of an F1 setup request (F1 SETUP REQUEST) described in Non-Patent Document 31 (3GPP TS38.473) or the signaling of a DU configuration update (GNB-DU CONFIGUTATION UPDATE). This may, for example, reduce the number of signalings from the DU to the CU. As another example, a new F1 signaling may be provided. This may, for example, eliminate the need to change the existing F1 signaling, thereby avoiding complexity in the design of the communication system.

[0275] As another example of the signaling used for the notification, the notification may be performed using RRC signaling. For example, in a base station with integrated access and backhaul (see Non-Patent Document 16 (3GPP TS38.300)), the notification may be performed using RRC signaling. RRC signaling for the notification may be provided, or the notification may be encapsulated in RRC signaling and transmitted. For example, the notification may be performed using signaling of the F1 interface encapsulated in RRC signaling, or may be performed using LPP signaling and / or NRPPa signaling using RRC signaling. This enables the notification from the DU to the CU, for example, even when the CU and the DU are connected wirelessly.

[0276] As another example of the signaling used for the notification, the notification may be performed using LPP signaling or NRPPa signaling. For example, the notification may be performed using a TRP INFORMATION RESPONSE disclosed in Non-Patent Document 24 (3GPP TS38.305). The CU may forward the information to the LMF.

[0277] The DU may terminate the LPP protocol and may terminate the NRPPa protocol, which allows, for example, quick notification of information about the DU's location to the LMF.

[0278] The following (a) to (f) are examples of information used in the notification from the DU to the CU.

[0279] (a) Information that identifies the DU.

[0280] (b) Information about the location of the DU.

[0281] (c) Time information.

[0282] (d) Information about positioning methods.

[0283] (e) Information similar to (a) through (c) above, or a combination thereof, regarding TRP.

[0284] (f) A combination of (a) to (e) above.

[0285] The information related to (a) above may be, for example, a DU identifier. The identifier may be, for example, a DU-ID. The CU may use the information to identify the DU that sent the notification. This allows, for example, the CU to easily identify the DU base station that sent the notification, thereby enabling the positioning procedure in the communication system to be performed quickly.

[0286] The information related to (b) above may be the same as the information (2) disclosed in the first embodiment as an example of information that the base station notifies the LMF. For example, the information may include information about the location of the DU, or information about the accuracy of the location of the DU. This allows the LMF to derive the accuracy of the UE location calculation, for example.

[0287] The information related to (c) above may be the same as the information (4) disclosed in the first embodiment as an example of information that the base station notifies the LMF. For example, it may include information about the time at which the DU's location is derived, or information about the accuracy of that time. The LMF may use that information to derive the UE's location at a certain time. This allows the LMF to improve the accuracy of deriving the UE's location, for example.

[0288] The information related to (d) above may be the same as the information (7) disclosed in the first embodiment as an example of information that the base station notifies the LMF. The LMF may use this information to obtain information related to the UE positioning method. This allows the LMF to quickly obtain information related to the UE positioning method, and as a result, the LMF can quickly perform UE positioning.

[0289] The information related to the above (e) may be, for example, information obtained by replacing DU with TRP in the above (a) to (c). The information related to the above (e) may be one piece, or may include multiple pieces, for example, the number of pieces equal to the number of TRPs. This makes it possible to improve the positioning accuracy of UEs, for example, even in a communication system using a base station having a TRP.

[0290] The CU may request the DU to notify information about its location. The request may be made by F1 signaling, RRC signaling, LPP signaling, or NRPPa signaling. For example, the request may be made using the TRP INFORMATION REQUEST disclosed in Non-Patent Document 24 (3GPP TS38.305), or may be made using a new signaling. The CU may terminate the LPP protocol or the NRPPa protocol. This may enable, for example, the LMF to quickly notify information about the DU's location.

[0291] Fig. 18 is a sequence diagram showing an example of a UE positioning sequence, including a process in which a DU notifies a CU of the location of its own DU. Fig. 18 shows a case in which multi-RTT is used as the positioning method. In Fig. 18, the same steps as in Fig. 14 are assigned the same step numbers, and common explanations will be omitted.

[0292] In FIG. 18, the processes with the same step numbers as those in FIG. 14 are processes in which the base station in each step in FIG. 14 is replaced with the CU.

[0293] In procedure 1805 shown in FIG. 18, the same processing as that in procedure 1405 in FIG. 14 is performed.

[0294] Step ST1407 shown in FIG. 18 is the same as that in FIG.

[0295] In step ST1807 shown in FIG. 18, the CU requests information about the location of the DU from the DU. Here, the CU is the CU of the serving base station (serving gNB-CU), and the DU is the DU of the serving base station (serving gNB-DU). This also applies to the following description. The request may be made by F1 signaling, RRC signaling, LPP signaling, or NRPPa signaling. For example, the request may be made using the TRP information request (TRP INFORMATION REQUEST) disclosed in Non-Patent Document 24 (3GPP TS38.305), or may be made using new signaling.

[0296] In Step ST1808 shown in FIG. 18, the DU notifies the CU of information related to the location of its own DU. This information may include the above-mentioned information (a) to (f) disclosed as examples of information used for the notification from the DU to the CU. The signaling in Step ST1808 may be performed using F1 signaling, RRC signaling, LPP signaling, or NRPPa signaling.

[0297] Step ST1409 shown in FIG. 18 is the same as that in FIG.

[0298] In step ST1851 shown in FIG. 18, the DU transmits a PRS to the UE.

[0299] In Step ST1857 shown in Fig. 18, the UE transmits an SRS to the DU. In Step ST1859, the DU performs a measurement process of the SRS.

[0300] 18, the DU notifies the CU of information related to the measurement result of the uplink SRS. The CU may include the notification of the information received in step ST1866 in the measurement result notification to the LMF shown in step ST1467. The CU may also notify the LMF of information related to the location of the DU notified in step ST1808 above when notifying the LMF of the measurement result.

[0301] The sequence shown in Fig. 18 may be applied to a case where a neighboring base station has a configuration in which the neighboring base station is divided into a CU and a DU. In this case, the DU of the neighboring base station may perform the process of step ST1808. This makes it possible to measure the position of the DU of the serving base station, for example, even when the neighboring base station is divided into a CU and a DU.

[0302] In the sequence shown in Figure 18, multiple DUs of the serving base station may be used. In the above, some DUs may be used for transmitting and receiving signaling, data, and / or positioning signals to and from the UE, and other DUs may transmit and receive positioning signals to and from the UE. In this case, surrounding base stations may or may not be used for positioning. Using surrounding base stations can, for example, improve the accuracy of UE positioning. Not using surrounding base stations can, for example, reduce the amount of signaling between the base station and the LMF.

[0303] The method disclosed in this embodiment may be used to notify information about the location of a TRP. For example, a DU may notify a CU of information about the location of a subordinate TRP. The information may include information about time. The CU may forward the information to an LMF. The LMF may use the information to calculate the location of the TRP. This makes it possible to improve the accuracy of UE positioning, for example, even when positioning is performed using a base station having a TRP.

[0304] According to the second embodiment, it becomes possible for the DU to notify the CU of information relating to the location of the DU itself, and as a result, it becomes possible to improve the accuracy of UE positioning in the LMF.

[0305] In this embodiment, an example in which the upper device has an LMF has been described, but the base station may have an LMF, or the UE may have an LMF.

[0306] Embodiment 3 5G base stations can support Integrated Access and Backhaul (IAB) (see Non-Patent Document 16 (3GPP TS38.300)). That is, UE positioning may be performed using a base station that supports IAB (hereinafter, sometimes referred to as an IAB base station). However, the above-mentioned Non-Patent Documents 1 to 33 and other standards that have been established so far do not disclose how positioning using an IAB base station is performed. This causes a problem in that positioning using an IAB base station cannot be performed.

[0307] Therefore, in the third embodiment, a method for solving the above-mentioned problem will be disclosed.

[0308] That is, in a communication system to which IAB is applied, an IAB node (a base station operating as an IAB node) notifies an IAB donor CU (a CU of a base station operating as an IAB donor) of information about its own location. The notification may be performed via an IAB parent node and / or an IAB donor DU.

[0309] F1 signaling may be used for this notification. The notification using F1 signaling may be used in combination with the notification method disclosed in the second embodiment. This allows the same I / F to be used for notification of information relating to the location of the own node, for example, regardless of whether the communication path between the CU and DU is wired or wireless, and as a result, complexity in the communication system can be avoided.

[0310] The F1 signaling may be encapsulated in RRC signaling, or may be encapsulated in signaling in a BAP (Backhaul Adaptation Protocol) sublayer disclosed in Non-Patent Document 16 (3GPP TS38.300).

[0311] As another example, RRC signaling may be used for the notification. Existing RRC signaling may be used, or RRC signaling used for notifying information about the location of the node may be provided. This allows, for example, the IAB node to quickly notify the IAB donor CU of its location.

[0312] The information included in the notification from the IAB node to the IAB donor CU may be the above information (a) to (f) used in the notification from the DU to the CU disclosed in embodiment 2, with the DU replaced with the IAB node. This allows the same I / F to be used for the communication path between the CU and DU, regardless of whether it is wired or wireless, for notification of information about the location of the node itself, and as a result, complexity in the communication system can be avoided.

[0313] Positioning of the IAB node may be performed. The positioning may be performed, for example, by transmitting and receiving positioning signals between the IAB node and the IAB donor DU, or between the IAB node and a neighboring base station. The positioning of the IAB node by transmitting and receiving positioning signals may be performed, for example, by using the method disclosed in Non-Patent Document 24 (3GPP TS38.305) or the methods disclosed in the first embodiment to the second modification of the first embodiment. In the above-mentioned methods, the UE may be replaced with the IAB node. The methods disclosed in the first embodiment to the second modification of the first embodiment may be used, for example, when the IAB donor DU moves. This makes it possible to calculate the position of the IAB donor DU at a certain time with high accuracy, thereby improving the accuracy of the position calculation of the IAB node.

[0314] An IAB node may be capable of terminating NAS signaling, LPP signaling, or NRPPa signaling, which allows, for example, transmission and reception using LPP signaling and / or NRPPa signaling between an LMF and an IAB node, thereby enabling positioning of the IAB node.

[0315] Fig. 19 is a sequence diagram showing an example of a positioning sequence of an IAB node. Fig. 19 shows a case where multi-RTT is used as the positioning method. In Fig. 19, the same processes as in Fig. 14 are assigned the same numbers, and detailed descriptions of these processes will be omitted.

[0316] In FIG. 19, the processing with the same procedure numbers and step numbers as in FIG. 14 is processing in which the serving base station is replaced with the IAB donor for each procedure and step in FIG.

[0317] Among the processes in Figure 19, the processes in which the third and fourth digits from the bottom of the procedure number and step number are "19" are the processes in which the first and second digits from the bottom of the procedure number and step number in Figure 14 are the same, but with the serving base station replaced with the IAB donor and the UE replaced with the IAB node.

[0318] The UE may be positioned using an IAB node. The positioning may be performed, for example, by transmitting and receiving a positioning signal between the UE and the IAB node, or between the UE and a neighboring base station. The positioning may be performed, for example, by using a method that combines the first embodiment to the second modification of the first embodiment with the second embodiment.

[0319] The positioning of the IAB node and the positioning of the UE may be performed separately. For example, the positioning of the IAB node may be performed after the positioning of the UE. In the above, for example, the positioning sequence shown in FIG. 19 and the positioning sequence shown in FIG. 14 may be used in combination. This may, for example, avoid complexity in the positioning process of the UE.

[0320] Positioning of the IAB node and the UE may be performed simultaneously. The positioning may be performed, for example, by transmitting and receiving positioning signals between the UE and the IAB node, between the UE and a neighboring base station, between the IAB node and an IAB donor DU, and between the IAB node and a neighboring base station. The positioning method may be performed by combining the methods disclosed in the first embodiment to the second modification of the first embodiment, the second embodiment, and the third embodiment. For example, the sequences shown in Figures 14, 18, and 19 may be combined and used. This may, for example, reduce latency in positioning.

[0321] Fig. 20 is a sequence diagram showing an example of a positioning sequence when positioning of an IAB node and a UE is performed simultaneously. Fig. 20 shows a case where multi-RTT is used as the positioning method. In Fig. 20, the same processes as those in Fig. 14, Fig. 18, and Fig. 19 are assigned the same numbers, and detailed descriptions of these processes will be omitted.

[0322] In FIG. 20, the processes having "14" in the third and fourth digits from the bottom of the procedure number and step number are the same as those in FIG.

[0323] In FIG. 20, the processes having "18" as the third and fourth digits from the bottom of the procedure number and step number are the same as those in FIG.

[0324] In FIG. 20, the processes in which the third and fourth digits from the bottom of the procedure number and step number are "19" are the same as those in FIG.

[0325] The IAB donor may determine whether or not the IAB node needs to be positioned. For example, the CU of the IAB donor may make the determination. The IAB donor may make the determination, for example, triggered by signaling of a TRP information request from the LMF, or by signaling of an SRS configuration request, or by a request for information on location and time from the LMF to the IAB donor (see embodiment 1), or the IAB donor may make the determination autonomously.

[0326] The determination at the IAB node may be made, for example, using information regarding the change in the position of the IAB node, or may be made using information regarding the positioning requirements, for example, the information (I) disclosed in embodiment 1 as information included in the request from the LMF to the base station.

[0327] The IAB donor may notify the LMF of information regarding whether or not IAB node positioning is required. The notification may be included in a TRP information response to the LMF, or new signaling may be provided for the notification. The LMF may use the information to initiate IAB node positioning or may not perform IAB node positioning. Not performing IAB node positioning may, for example, eliminate the need to perform unnecessary IAB node positioning, thereby reducing latency and the amount of signaling in the communication system.

[0328] The IAB node may terminate the LPP protocol between itself and the LMF, and may also terminate the NRPPa protocol, which allows, for example, for quick notification of information about the IAB node's location to the LMF.

[0329] According to the third embodiment, it becomes possible to locate the UE using the IAB base station.

[0330] In the first to third embodiments, a base station may notify other base stations of information relating to the location of the base station itself, information relating to the time, or information relating to the above-mentioned combinations. For example, a neighboring base station may notify a serving base station of information relating to the location of the base station itself and / or information relating to the time. The serving base station may notify the LMF of the information relating to the base station itself and / or the information relating to the neighboring base stations. This makes it possible to reduce the amount of signaling between the base station and the LMF, for example.

[0331] The serving base station may request information about the location and / or time of the base station from a neighboring base station. The neighboring base station may then notify the serving base station of information about the location and / or time of its own base station in response to the request. This, for example, makes it possible to reduce unnecessary signaling between base stations.

[0332] Embodiment 4 In SL communication, communication between a UE and a network via a relay has been proposed (see non-patent documents 20 (3GPP TR23.703) and 23 (3GPP TS23.303)). A relay between a UE and a network may be referred to as a UE-to-network relay or a UE-to-network relay. In this disclosure, a UE that performs relaying between a UE and a network may be referred to as a relay UE.

[0333] For example, there may be a need to communicate not only between UEs within the coverage of a RAN node (e.g., gNB) but also between UEs that are farther away and the RAN node. In such cases, a method using a UE-to-NW relay may be considered. For example, communication between a gNB and a UE (sometimes referred to as a remote UE) is performed via a relay UE. In this case, communication between the gNB and the relay UE is performed via Uu, and communication between the relay UE and the remote UE is performed via PC5.

[0334] In the relay of the side link, it is being considered to provide an adaptation layer between the RLC layer and the PDCP layer (see Non-Patent Document 32 (3GPP R2-2008254)).

[0335] However, the devices that should have an adaptation layer when a sidelink relay is used in a base station with CU-DU separation are not disclosed in the standards and the like that have been established so far, including the above-mentioned Non-Patent Documents 1 to 33. This causes a problem that, for example, interoperability is not guaranteed when the CU and DU are provided by different vendors, and relay using the sidelink does not work in the above-mentioned case.

[0336] Therefore, in this embodiment, a solution to the above problem is disclosed.

[0337] That is, in the communication system according to this embodiment, the CU has an adaptation layer. The DU does not have an adaptation layer. The PDU of the adaptation layer is transmitted and received via the F1 interface. In this case, the PDU of the adaptation layer may be an RLC SDU. This makes it possible to reduce the circuit scale of the DU, for example.

[0338] Figure 21 is a diagram showing an example of a protocol stack between a remote UE, a relay UE, a DU (gNB-DU) of a base station, and a CU (gNB-CU) of a base station when the CU has an adaptation layer. The protocol stack in Figure 21 is shown for U-plane data. The example shown in Figure 21 shows a case where the remote UE does not have an adaptation layer.

[0339] In Figure 21, the adaptation (ADAPT) layer is terminated between the relay UE and the gNB-CU, and the PDCP layer is terminated between the remote UE and the gNB-CU.

[0340] Although the case of the U-plane is shown in Figure 21, the same may be applied to the C-plane. For example, in the C-plane, the protocol stack below the PDCP layer may be the same as that in the U-plane. This makes it possible to avoid, for example, complexity in the communication system.

[0341] Although Fig. 21 shows a case where the remote UE does not have an adaptation layer, it may have an adaptation layer. In this case, the adaptation layer may be terminated between the remote UE and the relay UE, and between the relay UE and the gNB-CU, respectively. This can improve the flexibility of the communication system, for example.

[0342] Another solution is disclosed. The DU has an adaptation layer. The CU does not have an adaptation layer. The SDU of the adaptation layer is transmitted and received via the F1 interface. In this case, the SDU of the adaptation layer may be a PDCP PDU. This makes it possible to reduce the amount of processing by the CU, for example.

[0343] Figure 22 is a diagram showing an example of a protocol stack between a remote UE, a relay UE, a DU (gNB-DU) of a base station, and a CU (gNB-CU) of a base station when the DU has an adaptation layer. The protocol stack in Figure 22 shows U-plane data. The example shown in Figure 22 shows a case where the remote UE does not have an adaptation layer.

[0344] In Figure 22, the adaptation layer is terminated between the relay UE and the gNB-DU, and the PDCP layer is terminated between the remote UE and the gNB-CU.

[0345] Although the U-plane is shown in FIG. 22, the same can be applied to the C-plane. For example, in the C-plane, the protocol stack below the PDCP layer can be the same as that in the U-plane. This can avoid, for example, the complexity of the communication system.

[0346] Although Fig. 22 shows a case where the remote UE does not have an adaptation layer, it may have an adaptation layer. In this case, the adaptation layer may be terminated between the remote UE and the relay UE, and between the relay UE and the gNB-DU, respectively. This can improve the flexibility of the communication system, for example.

[0347] According to the fourth embodiment, interoperability becomes possible when the CU and DU are provided by different vendors.

[0348] Variation 1 of embodiment 4 When an IAB base station attempts to perform sidelink relay, the following problem occurs: Since the protocol stack including the BAP and the sidelink adaptation layer is not disclosed, sidelink relay using the IAB base station cannot be performed.

[0349] Therefore, in the first modification of this embodiment, a solution to the above problem is disclosed.

[0350] That is, in the communication system according to the first modification of the present embodiment, the BAP is arranged above the adaptation layer of the sidelink. The adaptation layer may be terminated between the relay UE and the IAB node, and between the IAB node and the IAB donor DU, respectively. This, for example, can improve the flexibility of the communication system.

[0351] Figure 23 is a diagram showing an example of a protocol stack between a remote UE, a relay UE, an IAB node, an IAB donor DU, and an IAB donor CU (gNB-CU) when a BAP is placed above an adaptation layer. The protocol stack in Figure 23 is shown for U-plane data. The example shown in Figure 23 shows a case where the remote UE does not have an adaptation layer.

[0352] 23, the adaptation layer is terminated between the relay UE and the IAB node, and between the IAB node and the IAB donor DU, respectively. The BAP is terminated between the IAB node and the IAB donor DU.

[0353] Although the case of the U-plane is shown in Figure 23, the same may be applied to the C-plane. For example, in the C-plane, the protocol stack below the PDCP layer may be the same as that in the U-plane. This makes it possible to avoid, for example, complexity in the communication system.

[0354] Although Fig. 23 shows a case where the remote UE does not have an adaptation layer, it may have an adaptation layer. In this case, an adaptation layer may be terminated between the remote UE and the relay UE, between the relay UE and the IAB node, and between the IAB node and the IAB donor DU. This can improve the flexibility of the communication system, for example.

[0355] Although FIG. 23 shows a case where there is one IAB node, multiple IAB nodes may be connected. For example, multiple IAB nodes may be connected in tandem. In this case, the protocol stack between the multiple IAB nodes may be the same as the protocol stack between the IAB node and the IAB donor DU. This, for example, can improve the flexibility of the communication system.

[0356] Another solution is disclosed. The sidelink adaptation layer is placed above the BAP. The IAB node does not need to process the adaptation layer protocol. This makes it possible to reduce the circuit scale in the IAB node, for example.

[0357] When the sidelink adaptation layer is located above the BAP, the IAB donor CU may process the adaptation layer, which may reduce the circuit size of the IAB donor DU, for example.

[0358] Figure 24 is a diagram showing an example of a protocol stack between a remote UE, a relay UE, an IAB node, an IAB donor DU, and an IAB donor CU (gNB-CU) when an adaptation layer is placed above a BAP. Figure 24 shows a case where the IAB donor CU has an adaptation layer. The protocol stack in Figure 24 shows U-plane data. The example shown in Figure 24 shows a case where the remote UE does not have an adaptation layer.

[0359] In Figure 24, the adaptation layer is terminated between the relay UE and the IAB donor CU, and the BAP is terminated between the IAB node and the IAB donor DU.

[0360] Although the case of the U-plane is shown in Figure 24, the same may be applied to the C-plane. For example, in the C-plane, the protocol stack below the PDCP layer may be the same as that in the U-plane. This makes it possible to avoid, for example, complexity in the communication system.

[0361] Although Fig. 24 shows a case where the remote UE does not have an adaptation layer, it may have an adaptation layer. In this case, an adaptation layer may be terminated between the remote UE and the relay UE, between the relay UE and the IAB node, and between the IAB node and the IAB donor DU. This can improve the flexibility of the communication system, for example.

[0362] Although FIG. 24 shows a case where there is one IAB node, multiple IAB nodes may be connected. For example, multiple IAB nodes may be connected in tandem. In this case, the protocol stack between the multiple IAB nodes may be the same as the protocol stack between the IAB node and the IAB donor DU. This, for example, can improve the flexibility of the communication system.

[0363] When the sidelink adaptation layer is located above the BAP, the IAB donor DU may process the adaptation layer, which may reduce the amount of processing by the IAB donor CU, for example.

[0364] Figure 25 is a diagram showing another example of a protocol stack between a remote UE, a relay UE, an IAB node, an IAB donor DU, and an IAB donor CU (gNB-CU) when an adaptation layer is placed above a BAP. Figure 25 shows a case where the IAB donor DU has an adaptation layer. The protocol stack in Figure 25 shows U-plane data. The example shown in Figure 25 shows a case where the remote UE does not have an adaptation layer.

[0365] In Figure 25, the adaptation layer is terminated between the relay UE and the IAB donor DU, and the BAP is terminated between the IAB node and the IAB donor DU.

[0366] Although the case of the U-plane is shown in Figure 25, the same may be applied to the C-plane. For example, in the C-plane, the protocol stack below the PDCP layer may be the same as that in the U-plane. This makes it possible to avoid, for example, complexity in the communication system.

[0367] Although Fig. 25 shows a case where the remote UE does not have an adaptation layer, it may have an adaptation layer. In this case, an adaptation layer may be terminated between the remote UE and the relay UE, between the relay UE and the IAB node, and between the IAB node and the IAB donor DU. This can improve the flexibility of the communication system, for example.

[0368] Although FIG. 25 shows a case where there is one IAB node, multiple IAB nodes may be connected. For example, multiple IAB nodes may be connected in tandem. In this case, the protocol stack between the multiple IAB nodes may be configured such that the PHY, MAC, RLC, and BAP terminate with each other. This, for example, can improve the flexibility of the communication system.

[0369] Another solution is disclosed. An adaptation layer is used between the relay UE and the IAB node, and a BAP is used between the IAB nodes and between the IAB node and the IAB donor DU. In this case, only the IAB node directly connected to the relay UE may process the adaptation layer. This eliminates the need for a header and / or trailer of the adaptation layer between the IAB nodes and between the IAB node and the IAB donor DU, thereby reducing the size of data transmitted and received between the IAB nodes and between the IAB node and the IAB donor DU.

[0370] Figure 26 is a diagram showing an example of a protocol stack between a remote UE, a relay UE, an IAB node, an IAB donor DU, and an IAB donor CU (gNB-CU) when an adaptation layer is used between the relay UE and the IAB node, and a BAP is used between the IAB nodes and between the IAB node and the IAB donor DU. The protocol stack in Figure 26 is shown for U-plane data. The example shown in Figure 26 shows a case where the remote UE does not have an adaptation layer.

[0371] In Figure 26, the adaptation layer is terminated between the relay UE and the IAB node. The BAP is terminated between the IAB node and the IAB donor DU. Neither the IAB donor DU nor the IAB donor CU has an adaptation layer.

[0372] Although the case of the U-plane is shown in Figure 26, the same may be applied to the C-plane. For example, in the C-plane, the protocol stack below the PDCP layer may be the same as that in the U-plane. This makes it possible to avoid, for example, complexity in the communication system.

[0373] Although Fig. 26 shows a case where the remote UE does not have an adaptation layer, it may have an adaptation layer. In this case, the adaptation layer may be terminated between the remote UE and the relay UE, and between the relay UE and the IAB node. This can improve the flexibility of the communication system, for example.

[0374] Although FIG. 26 shows a case where there is one IAB node, multiple IAB nodes may be connected. For example, multiple IAB nodes may be connected in tandem. In this case, the protocol stack between the multiple IAB nodes may be configured such that the PHY, MAC, RLC, and BAP terminate with each other. This, for example, can improve the flexibility of the communication system.

[0375] According to this first modification, relaying using a side link can be performed in the IAB base station.

[0376] In the present disclosure, the UE in which service data is generated is referred to as UE-TX. For example, if UE-TX is referred to as UE1 and UE-RX is referred to as UE2, when service data is generated in UE2 and the data is transmitted to UE1, it is advisable to apply the method of the present disclosure by regarding UE2 as UE-TX and UE1 as UE-RX. This can achieve the same effect.

[0377] 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.

[0378] 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.

[0379] For example, the methods disclosed in the above-described embodiments and their modifications 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.

[0380] Although the present disclosure has been described in detail, the above description is illustrative in all respects and is not restrictive. It is understood that countless variations not illustrated can be envisioned. [Explanation of symbols]

[0381] 200, 210 Communication system, 202 Communication terminal device (communication terminal), 203, 207, 213, 217, 223-1, 224-1, 224-2, 226-1, 226-2, 750 Base station device (base station), 204 MME / S-GW unit (MME unit), 204a MME, 214 AMF / SMF / UPF unit (5GC unit), 218 Central unit, 219 Distributed unit, 301, 403 Protocol processing unit, 302 Application unit, 303, 404 Transmission data buffer 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, 506, 526 Control unit, 401 EPC communication unit, 402 Other base station communication unit, 412 5GC communication unit, 501 PDN GW communication unit, 502, 522 Base station communication unit, 503, 523 User plane communication unit, 504 HeNBGW communication unit, 505, 525 Control plane control unit, 505-1, 525-1 NAS security unit, 505-2 SAE bearer control unit, 505-3, 525-3 Idle state mobility management unit, 521 Data Network communication unit, 525-2 PDU session control unit, 527 Session management unit, 751-1 to 751-8 Beam.

Claims

1. A base station; a communication terminal connected to the base station; Equipped with the base station transmits a reception result of the uplink positioning signal transmitted by the communication terminal and position information of the base station to a positioning execution device which is a device having a positioning function for deriving the position of the communication terminal; the communication terminal transmits a reception result of the downlink positioning signal transmitted by the base station to the positioning execution device; A communication system comprising:

2. the base station transmits, to the positioning execution device, information on the time at which the position information of the base station itself was derived in association with the position information; 2. The communication system according to claim 1.

3. The base station comprises a central unit and one or more distributed units; the location information indicates the location of each of the distributed units; 3. The communication system according to claim 1 or 2.

4. A communication system comprising a base station capable of supporting access / backhaul integration, a first base station operating as a donor of the integrated access / backhaul system transmits a reception result of a positioning signal transmitted by a second base station operating as a node of the integrated access / backhaul system and location information of the first base station to a positioning execution device which is a device having a positioning function for deriving a position of the second base station; the second base station transmits to the positioning execution device a reception result of the positioning signal transmitted by the first base station; A communication system comprising:

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