WO2023233645A1

WO2023233645A1 - User terminal, base station, wireless communication method, and storage medium

Info

Publication number: WO2023233645A1
Application number: PCT/JP2022/022591
Authority: WO
Inventors: 文絵田畑; 克成上村
Original assignee: ソフトバンク株式会社
Priority date: 2022-06-03
Filing date: 2022-06-03
Publication date: 2023-12-07

Abstract

The present invention provides a technology related to reducing communication or processing latency in communications utilizing a non-terrestrial network (NTN). Provided is a user terminal comprising: a control unit that determines whether a neighboring cell includes an NTN cell, which is cell formed by a non-terrestrial base station; and a communication unit that, in response to the control unit determining that the neighboring cell includes the NTN cell, transmits a first notification containing the cell global identity (CGI) of the neighboring cell to the base station.

Description

User terminal, base station, wireless communication method, and storage medium

The present invention relates to a user terminal, a base station, a wireless communication method, and a storage medium.

3GPP (Third Generation Partnership Project), an international standardization organization, has introduced NR (New Radio), which is a fifth generation (5G) RAT (Radio Access Technology), as a successor to LTE (Long Term Evolution) and LTE-Advanced ) Release 15 has been specified (for example, Non-Patent Document 1).

Release 15 introduces specifications regarding non-terrestrial networks (NTN). NTN is a network with an expanded communication area via non-terrestrial media such as satellites or High Altitude Platform Stations (HAPS). In NTN, it is assumed that at least part of the functions of a base station will be mounted on a satellite or HAPS (for example, an unmanned aerial system or unmanned aircraft).

Normally, cell identification information (e.g. PCI: Physical Cell Identity) is set so as not to collide in the same area, but non-terrestrial base stations based on NTN technology may move, so When the non-terrestrial base station forms a cell in the sky above an area where a There is also a possibility that the cell identification information overlaps, causing a delay in communication or processing.

An object of the present invention is to provide a technology related to reducing communication or processing delays in communication using NTN.

A user terminal according to one aspect of the present invention includes a control unit that determines whether a neighboring cell includes an NTN (Non-Terrestrial Network) cell that is a cell formed by non-terrestrial base stations; and a communication unit that transmits a first notification including a CGI (Cell Global Identity) of the neighboring cell to the base station in response to determining that the NTN cell is included in the neighboring cell.

A base station according to one aspect of the present invention transmits information set based on the fact that neighboring cells include an NTN (Non-Terrestrial Network) cell, which is a cell formed by non-terrestrial base stations, to a user terminal. a communication unit that receives a notification including a PCI (Physical Cell Identity) of a neighboring cell and a CGI (Cell Global Identity) from the user terminal in response to the transmission; The control unit includes a control unit that determines whether or not a collision has occurred between the PCI and a pre-stored PCI of a neighboring cell.

In the wireless communication method according to one aspect of the present invention, in the information processing apparatus, the control unit determines whether neighboring cells include NTN (Non-Terrestrial Network) cells that are cells formed by non-terrestrial base stations. and in response to the control unit determining that the NTN cell is included in the neighboring cells, the communication unit sends a first notification including the CGI (Cell Global Identity) of the neighboring cells. and transmitting to a base station.

A wireless communication method according to one aspect of the present invention is based on the fact that in an information processing device, a communication unit includes an NTN (Non-Terrestrial Network) cell, which is a cell formed by non-terrestrial base stations, as a neighboring cell. In response to transmitting the information set by the user terminal to the user terminal, the control unit receives a notification including the PCI (Physical Cell Identity) and CGI (Cell Global Identity) of the neighboring cell from the user terminal; , determining whether a collision has occurred between the PCI included in the notification received by the communication unit and the PCI of a neighboring cell stored in advance.

A storage medium according to one aspect of the present invention controls an information processing apparatus to determine whether neighboring cells include an NTN (Non-Terrestrial Network) cell, which is a cell formed by a non-terrestrial base station. and a communication unit that transmits a first notification including CGI (Cell Global Identity) of the neighboring cell to the base station in response to the control unit determining that the NTN cell is included in the neighboring cell. Stores a program for functioning as a user terminal equipped with.

A storage medium according to one aspect of the present invention is configured such that an information processing apparatus is configured based on the fact that neighboring cells include NTN (Non-Terrestrial Network) cells, which are cells formed by non-terrestrial base stations. a communication unit that receives a notification including a PCI (Physical Cell Identity) of a neighboring cell and a CGI (Cell Global Identity) from the user terminal in response to transmitting information to the user terminal; A program for functioning as a base station is stored, including a control unit that determines whether or not a collision has occurred between the PCI included in the notification and the pre-stored PCI of a neighboring cell.

According to the present invention, it is possible to provide a technique for reducing communication or processing delays in communication using NTN.

FIG. 1 is a diagram illustrating an example of an overview of a wireless communication system according to the present embodiment. 1 is a diagram showing an example of the hardware configuration of each device in the wireless communication system according to the present embodiment. FIG. 2 is a diagram illustrating an example of a functional block configuration of a user terminal according to the present embodiment. FIG. 2 is a diagram illustrating an example of a functional block configuration of a base station according to the present embodiment. FIG. 2 is a diagram illustrating an example of processing by the wireless communication system according to the present embodiment.

Embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, those with the same reference numerals may have the same or similar configurations.

(Overview of wireless communication system)
FIG. 1 is a diagram illustrating an example of an overview of a wireless communication system according to the present embodiment. The wireless communication system 1 forms a network including a non-terrestrial network (NTN). As shown in FIG. 1, the wireless communication system 1 may include a user terminal 10, a base station 20A, a base station 20B, a base station 20C, and a core network 30. The base station 20A and the base station 20B are, for example, base stations on the ground. The base station 20C is, for example, a movable non-terrestrial base station, and is a base station that forms a cell from the sky. Hereinafter, cells formed by non-terrestrial base stations will also be referred to as NTN cells. The base station 20C may be mounted, for example, on a flying object 40 flying in the sky, and may function as a high altitude platform station (HAPS). Cell C1 is associated with base station 20A, cell C2 is associated with base station 20B, and cell C3 is associated with base station 20C.

Note that if the base station 20A, base station 20B, and base station 20C are not distinguished from each other, they are collectively referred to as the base station 20. When cell C1, cell C2, and cell C3 are not distinguished from each other, they are collectively referred to as cell C. Further, the numbers of user terminals 10, base stations 20, and cells C shown in FIG. 1 are merely examples, and are not limited to the numbers shown.

The wireless communication system 1 operates using one or more radio access technologies (RAT). For example, the wireless communication system 1 may operate in either LTE, LTE-Advanced, or NR, or may operate in multiple RATs (multi-RAT) including LTE and/or LTE-Advanced and NR. You may. LTE and/or LTE-Advanced is also referred to as Evolved-Universal Terrestrial Radio Access (E-UTRA).

Additionally, the wireless communication system 1 operates in one or more frequency ranges (FR). For example, the wireless communication system 1 may operate with FR1 corresponding to 410 MHz to 7125 MHz and/or FR2 corresponding to 24250 MHz to 52600 MHz. Each FR includes one or more frequency bands. The frequency band is also called an operating band, band, NR operating band, NR band, etc.

A plurality of ARFCNs (Absolute Radio Frequency Channel Numbers) are associated with each frequency band. ARFCN may identify a frequency (hereinafter referred to as "carrier frequency") at which a carrier is placed within a frequency band. The carrier frequency is also called an RF reference frequency, NR frequency, E-UTRA frequency, center frequency, channel raster, simply frequency, etc. In this way, ARFCN and carrier frequency are uniquely associated. Also, one carrier frequency may be used in one or more cells C.

The user terminal 10 is, for example, a predetermined terminal or device such as a smartphone, a personal computer, a vehicle-mounted terminal, a vehicle-mounted device, or a stationary device. The user terminal 10 may be called user equipment (UE) or the like. The user terminal 10 may be mobile or fixed. The user terminal 10 is configured to be able to communicate using at least one RAT of E-UTRA and NR, for example.

The base station 20 forms one or more cells C. The cell C may also be referred to as a carrier, a component carrier (CC), or the like. Note that in FIG. 1, the base stations 20A, 20B, and 20C form cells C1, C2, and C3, but the present invention is not limited to this, and each base station may form one or more cells C. Further, the plurality of base stations 20 may be connected by an ideal backhaul or a non-ideal backhaul. Further, the plurality of base stations 20 may be connected through a predetermined interface (for example, an X2 or Xn interface).

The base station 20 communicates with the user terminal 10. The base station 20 is an eNodeB (eNB), ng-eNB, gNodeB (gNB), en-gNB, Next Generation-Radio Access Network (NG-RAN) node, Donor eNodeB (DeNB), Donor eNodeB (DeNB), Donor node , or Central Unit, low-power node, pico eNB, Home eNB (HeNB), Distributed Unit (DU), gNB-DU, Remote Radio Head (RRH), Integrated Access and Backhaul/Backhauling (IAB ) node, node, master node (MN), secondary node (SN), etc. Note that the base station 20 that operates in NR may also be called an "NR base station," and the base station 20 that operates in E-UTRA may be called an "E-UTRA base station."

The core network 30 is, for example, a core network compatible with E-UTRA (Evolved Packet Core: EPC) or a core network compatible with NR (5G Core Network: 5GC). Devices on the core network 30 (hereinafter also referred to as "core network devices") perform mobility management such as paging and location registration of the user terminals 10. The core network device may be connected to the base station 20 via a predetermined interface (eg, S1 or NG interface).

The core network device includes, for example, a Mobility Management Entity (MME) that manages the movement of the user terminal 10, an Access and Mobility Management Function (AMF) that manages C-plane information (for example, information related to access and movement management, etc.), and a U It may also include at least one User Plane Function (UPF) that controls transmission of plane information (for example, user data).

(Detailed configuration of wireless communication system)
The detailed configuration of each device of the wireless communication system 1 will be explained. It should be noted that the following configuration is for showing the necessary configuration in the description of this embodiment, and does not exclude that each device is provided with functional blocks other than those shown in the drawings.

<Hardware configuration>
FIG. 2 is a diagram showing an example of the hardware configuration of each device in the wireless communication system according to the present embodiment. Each device in the wireless communication system 1 (for example, each of the user terminal 10 and the base station 20) includes a processor 10a, a memory 10b, a storage device 10c, a communication device 10d, an input device 10e, an output device 10f, and one or more antennas A. have at least

The processor 10a is, for example, a CPU (Central Processing Unit), and controls each device within the wireless communication system 1. The processor 10a may constitute a control unit that controls each device.

The memory 10b includes, for example, ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and/or RAM (Random Access Memory).

The storage device 10c is composed of storage such as, for example, an HDD (Hard Disk Drive), an SSD (Solid State Drive), and/or an eMMC (Embedded Multi Media Card).

The communication device 10d is a device that performs communication via a wired and/or wireless network, and is, for example, a network adapter, a communication module, or the like. Further, the communication device 10d may include an amplifier, an RF (Radio Frequency) device that performs processing related to wireless signals, and a BB (BaseBand) device that performs baseband signal processing.

The RF device generates a radio signal to be transmitted from antenna A by, for example, performing D/A conversion, modulation, frequency conversion, power amplification, etc. on the digital baseband signal received from the BB device. Further, the RF device generates a digital baseband signal by performing frequency conversion, demodulation, A/D conversion, etc. on the radio signal received from antenna A, and transmits the digital baseband signal to the BB device. The BB device performs a process of converting a digital baseband signal into an IP packet, and a process of converting an IP packet into a digital baseband signal.

The input device 10e is a device that accepts various inputs, such as a keyboard, touch panel, mouse, and/or microphone. The output device 10f is a device that outputs various information, and is, for example, a display and/or a speaker.

Although not shown, each device (for example, each of the user terminal 10 and the base station 20) further includes a power source and a power amplifier. The power source supplies driving power for each device and includes, for example, a battery. A power amplifier is a device that amplifies the power supplied from a power source to the drive power required by each component of each device.

<Functional block configuration>
≪User terminal≫
FIG. 3 is a diagram showing an example of the functional block configuration of the user terminal 10 according to the present embodiment. As shown in FIG. 3, the user terminal 10 includes a receiving section 11, a transmitting section 12, a storage section 13, a measuring section 14, and a control section 15.

The receiving unit 11 receives the downlink signal. Downlink signals include, for example, a broadcast channel (Physical Broadcast Channel (PBCH)), a synchronization signal (SS), a downlink shared channel (Physical Downlink Shared Channel (PDSCH)), and downlink control. It may be at least one of a channel (physical downlink control channel (PDCCH)), a downlink reference signal, etc.

The synchronization signal may include a primary synchronization signal (PSS) and/or a secondary synchronization signal (PSS). A block including a synchronization signal and PBCH may be called an SS/PBCH block, a synchronization signal block (SSB). The downlink reference signal may include, for example, at least one of a demodulation reference signal (DMRS) of PDCCH and/or PDSCH, a channel state information reference signal (CSI-RS), etc. .

Additionally, the receiving unit 11 may perform processing related to reception of information and/or data transmitted via the downlink signal (for example, reception, demapping, demodulation, decoding, etc.). Specifically, the receiving unit 11 receives information requesting capability information of the user terminal 10 (hereinafter referred to as "capability information request"). The capability information request is transmitted from the base station 20 to the user terminal 10 by upper layer signaling, and may be an RRC message "UECapabilityEnquiry", for example.

Additionally, the receiving unit 11 may receive a notification that includes information that is set based on whether or not ephemeris information is stored in the base station 20. The ephemeris information includes position information or trajectory information of base stations 20 (that is, non-terrestrial base stations 20) forming neighboring cells from the sky. The ephemeris information may include, for example, position information or orbit information of the flying object 40 carrying the base station 20C (or position information or activation information of the base station 20C).

The above information that is set based on whether or not ephemeris information is stored in the base station 20 may be information indicating whether or not ephemeris information is stored, or may be indicated by a flag. , may be indicated by a signal pattern, or may be indicated by any other arbitrary method.

NTN cells formed by non-terrestrial base stations 20 may move, so if an NTN cell is formed in an area where a cell has already been formed by a terrestrial base station 20, the NTN cell formed by a terrestrial base station 20 may be moved. There is a possibility that the PCI (Physical Cell Identity) of the NTN cell will collide with the PCI of the NTN cell. Therefore, the above notification including information set based on whether or not ephemeris information is stored in the base station 20 can also be understood as a notification indicating that a PCI collision may occur.

The above information, which is set based on whether or not ephemeris information is stored in the base station 20, is transmitted from the base station 20 to the user terminal 10, for example, in a system information block (SIB) on the PDSCH. may be done. That is, the notification sent from the base station 20 to the user terminal 10 may include a system information block that includes information set based on whether or not ephemeris information is stored in the base station 20.

The measuring unit 14 measures at least part of the received power, received quality, and received timing of the downlink signal in the neighboring cell C. The above received power is, for example, Reference Signal Received Power (RSRP), Synchronization Signal based Reference Signal Received Power (SS-RSRP) (also called SS/PBCH block RSRP), or CSI-RS based Reference Signal Received Power (CSI-RSRP). RS-RSRP). The reception quality may be, for example, Reference Signal Received Quality (RSRQ) or Signal to Interference plus Noise Ratio (SINR). The reception timing may be, for example, the start timing of a time unit (for example, a subframe or slot) in each cell.

The control unit 15 performs various controls in the user terminal 10. Specifically, the control unit 15 may determine whether the neighboring cells include an NTN cell, which is a cell C formed by the non-terrestrial base station 20. A determination as to whether an NTN cell is included in the neighboring cells is made by any method.

For example, the control unit 15 may determine whether or not the neighboring cells include an NTN cell, based on a notification received from the base station 20 via the reception unit 11. Specifically, the notification includes information that is set depending on whether an NTN cell is included in the neighboring cells of the base station 20, and the control unit 15 controls the neighboring cells based on the information. , it may be determined whether an NTN cell is included.

The receiving unit 11 receives a notification from the base station 20 that includes information set based on whether ephemeris information is stored in the base station 20, and the control unit 15 sends information to neighboring cells based on the notification. , it may be determined whether an NTN cell is included. For example, if the NTN cell C3 is included in the neighboring cells of the base station 20A, the ephemeris information of the base station 20C forming the NTN cell C3 may be stored in the base station 20A.

The transmitter 12 transmits an uplink signal. Uplink signals include, for example, a random access channel (Physical Random Access Channel (PRACH)), an uplink control channel (Physical Uplink Control Channel (PUCCH)), an uplink shared channel (Physical Uplink Shared Channel ( Physical Uplink Shared Channel (PUSCH)), uplink reference signal, etc. The uplink reference signal may be, for example, DMRS of PUCCH and/or PUSCH, Sounding Reference Signal (SRS) It may also include at least one of the following.

The transmitter 12 may perform processing related to the transmission of information and/or data transmitted via the uplink signal (for example, transmission, mapping, modulation, coding, etc.). Specifically, the transmitter 12 transmits capability information of the user terminal 10. Capability information is information regarding the capability of the user terminal 10, and may include information indicating whether the user terminal 10 supports various requirements and/or functions. Further, the capability information is transmitted from the user terminal 10 to the base station 20 by upper layer signaling, and may be, for example, "UECapabilityInformation" of the RRC IE. The transmitter 12 may transmit signals other than those described above.

In response to the control unit 15 determining that the neighboring cells include the NTN cell, the transmitting unit 12 sends a notification to the base station 20 that includes CGI (Cell Global Identity) in addition to the PCI of the neighboring cells. You can also send it.

The transmitting unit 12 may transmit to the base station 20 a notification that includes the measurement results of neighboring cells by the measuring unit 14 as a measurement report (MR). The measurement report may include, for example, at least a portion of the received power and received quality of the downlink signal in the neighboring cell C, and the PCI of the corresponding cell C. In response to the control unit 15 determining that the neighboring cells include the NTN cell as described above, the measurement report may include the CGI in addition to the PCI of the neighboring cell.

As described above, according to the present embodiment, the control unit 15 may determine whether the neighboring cells include the NTN cell C, which is the cell C formed by the non-terrestrial base station 20. The transmitting unit 12 may transmit a notification including the CGI of the neighboring cell to the base station 20 in response to the control unit 15 determining that the NTN cell C is included in the neighboring cells.

In the prior art, in response to the occurrence of a PCI collision of neighboring cells stored in the base station 20, a CGI report procedure is used to transmit the CGI from the base station 20 to the user terminal 10 for the cell in which the PCI collision has occurred. There were cases in which a report was requested and a CGI was transmitted from the user terminal 10 to the base station 20. On the other hand, according to the present embodiment, as described above, the control unit 15 of the user terminal 10 detects that the neighboring cells include the NTN cell C (that is, the PCI of the NTN cell C and other PCIs collide). In response to determining that the possibility has arisen, the transmitter 12 transmits a notification including the CGI of the neighboring cell to the base station 20. That is, when a PCI collision occurs, the base station 20 can obtain the CGI of a neighboring cell without performing a CGI reporting procedure (eg, transmitting and receiving a Report Global-CID Request message and a Report Global-CID message). As a result, according to the present embodiment, it is possible to realize a technique related to reducing communication or processing delays in communication using NTN. Furthermore, as a result of the above, the technology according to the present embodiment can contribute to achieving Goal 9 of the Sustainable Development Goals (SDGs), "Create a foundation for industry and technological innovation."

The storage unit 13 stores various information. The storage unit 13 may store, for example, an upper limit value of transmission power by the transmission unit 12, threshold values necessary for various processes, information received via a downlink signal, and the like.

Note that the storage unit 13 may be realized by, for example, the storage device 10c. The receiving unit 11, the transmitting unit 12, and the measuring unit 14 may be realized, for example, by the communication device 10d, or may be realized by the processor 10a executing a program stored in the storage device 10c in addition to the communication device 10d. Good too. The control unit 15 may be realized by the processor 10a executing a program stored in the storage device 10c. When executing a program, the program may be stored in a storage medium. The storage medium storing the program may be a non-transitory computer readable medium. The non-temporary storage medium is not particularly limited, and may be, for example, a USB (Universal Serial Bus) memory or a CD-ROM (Compact Disc ROM).

≪Base station≫
FIG. 4 is a diagram showing an example of the functional block configuration of the base station 20 according to this embodiment. As shown in FIG. 4, the base station 20 includes a transmitter 21, a receiver 22, a controller 23, and a storage 24.

The transmitter 21 transmits a downlink signal. Further, the transmitting unit 21 performs processing regarding information and/or data transmitted via the downlink signal (for example, encoding, decoding, mapping to resources, etc.). Specifically, the transmitter 21 may transmit at least one of the capability information request and the RRC reconfiguration message.

Furthermore, the transmitter 21 may transmit information set based on the fact that the neighboring cells include an NTN cell, which is a cell formed by the non-terrestrial base station 20, to the user terminal 10. Whether or not the neighboring cells include an NTN cell, which is a cell formed by a non-terrestrial base station 20, is determined based on whether or not ephemeris information of the base station 20 is stored in the storage unit 24, as will be described later. It may be determined that The ephemeris information includes position information or trajectory information of base stations 20 (that is, non-terrestrial base stations 20) forming neighboring cells from the sky. The above information that is set based on whether or not ephemeris information is stored in the base station 20 may be indicated by a flag, a signal pattern, or any other arbitrary method. It's okay.

The receiving unit 22 receives the upstream signal. Further, the receiving unit 22 performs processing (for example, demapping, demodulation, decoding, etc.) regarding information and/or data transmitted via the uplink signal. Specifically, the receiving unit 22 may receive at least one of the ability information and the cumulative value information.

As described above, the transmitting unit 21 of the base station 20 transmits to the user terminal 10 information set based on the fact that the neighboring cells include an NTN cell, which is a cell formed by the non-terrestrial base station 20. Accordingly, the user terminal 10 may send a notification to the base station 20 that includes the CGI in addition to the PCI of the neighboring cell. The receiving unit 22 of the base station 20 receives the notification. The notification may include the measurement results of neighboring cells by the user terminal 10 as a measurement report.

Note that the transmitter 21 and the receiver 22 may be realized, for example, by the communication device 10d, or may be realized by the processor 10a executing a program stored in the storage device 10c in addition to the communication device 10d. . The control unit 23 may be realized by the processor 10a executing a program stored in the storage device 10c.

The storage unit 24 stores various information. The storage unit 24 may store, for example, threshold values necessary for various processes, information received via the reception unit 22, and the like. The storage unit 24 may store a neighboring cell information table that is a table including information on neighboring cells of the base station 20 in order to understand handover destination candidates of the user terminal 10 and the like. Such a neighbor cell information table is called, for example, a Neighbor Cell Relation Table (NCRT). In the neighboring cell information table, information on neighboring cells may be automatically deleted and added by Auto Neighbor Cell Relation (ANR), or information on neighboring cells may be deleted and added by an administrator.

The above neighboring cell information table may include ephemeris information of non-terrestrial base stations 20 forming NTN cells among neighboring cells. If the NTN cell is not included in the neighboring cells, the neighboring cell information table described above does not include ephemeris information of the non-terrestrial base station 20.

The control unit 23 performs various controls regarding communication between the user terminal 10 and the base station 20. For example, the control unit 23 controls the transmission of downlink signals by the transmitting unit 21 and/or the reception of uplink signals by the receiving unit 22.

The control unit 23 also controls the connection between the PCI received by the reception unit 22 from the user terminal 10 as described above (for example, the PCI included in the measurement report) and the PCI of the neighboring cell stored in advance in the storage unit 24. It may also be determined whether a collision (PCI collision) has occurred. Normally, PCIs are set so as not to collide in the same area, but for example, NTN cells formed by non-terrestrial base stations 20 may move. Therefore, when an NTN cell is formed in an area where a cell has already been formed by the base station 20 on the ground, a PCI collision occurs between the PCI of the cell formed by the base station 20 on the ground and the PCI of the NTN cell. can occur.

As described above, according to the present embodiment, the transmitter 21 transmits information set based on the fact that the neighboring cells include an NTN cell, which is a cell formed by the non-terrestrial base station 20, to the user terminal 10. In response to the transmission via the user terminal 10, the receiving unit 22 receives a notification including the PCI and CGI of the neighboring cell from the user terminal 10. The control unit 23 determines whether a collision has occurred between the PCI included in the notification received by the reception unit 22 and the PCI of the neighboring cell stored in advance in the storage unit 24. Therefore, according to the present embodiment, when a PCI collision occurs, the base station 20 performs CGI reporting without executing the CGI reporting procedure (for example, sending and receiving the Report Global-CID Request message and the Report Global-CID message). Can be obtained.

In response to the controller 23 determining that a PCI conflict has occurred, the transmitter 21 may transmit a notification indicating that a PCI conflict has occurred via the Xn link. That is, the notification may be transmitted from the base station 20 to other base stations 20. The notification may be, for example, NG-RAN NODE CONFIGURATION UPDATE.

In response to the controller 23 determining that a PCI conflict has occurred, the transmitter 21 may transmit a notification indicating that a PCI conflict has occurred via the NG link. That is, the notification may be sent from the base station 20 to the core network 30 (for example, AMF). The notification may be, for example, RAN CONFIGURATION UPDATE or AMF CONFIGURATION UPDATE.

(Operation of wireless communication system)
Next, the operation of the wireless communication system 1 configured as above will be explained. Note that the operations described below are merely examples, and some steps may be omitted, steps not shown may be performed, or the order of the steps may be changed to the extent that no problems occur. Of course, this is a good thing.

A first example of processing in the wireless communication system 1 according to the present embodiment will be described with reference to FIG. 5. FIG. 5 shows a case in which an NTN cell C3 formed at the base station 20C is included in the neighboring cells of the cell C1 formed at the base station 20A and the cell C2 formed at the base station 20B. An example of a processing flow performed by the station 20A, the base station 20B, and the AMF 301 is shown. AMF 301 is a configuration included in core network 30.

In step S101, the base station 20A determines whether the ephemeris information of the base station 20C is stored in the base station 20A as neighboring cell information. If it is determined that the ephemeris information is stored, the base station 20A includes information set according to the fact that the ephemeris information is stored, for example, in a system information block (SIB) in the PDSCH and transmits the information to the user. Send to terminal 10.

In step S102, the user terminal 10 determines whether the system information block received in step S101 includes information set in response to the ephemeris information being stored. If it is determined that the CGI is included in the neighboring cell, the user terminal 10 includes the CGI in a measurement report (MR) of the measurement results of the neighboring cell in addition to the PCI of the neighboring cell, and sends the measurement report to the base station 20A. Send to.

In the prior art, the measurement report includes, for example, at least part of the received power and received quality of the downlink signal in the neighboring cell C, and the PCI of the corresponding cell C. In this embodiment, as described above, when the control unit 15 determines that the information set in response to the ephemeris information being stored is included in the system information block received in step S101, Then, the CGI of the neighboring cell may be included in the measurement report and transmitted.

In step S103, the base station 20A detects that a conflict (PCI Conflict) has occurred between the PCI included in the measurement report received in step S102 and the PCI of a neighboring cell stored in advance in the base station 20A. Determine whether or not there is. If it is determined that a PCI conflict has occurred, the following process including at least a portion of steps S104 to S109 may be executed.

As described above, according to the present embodiment, the user terminal 10 is informed that the neighboring cells include the NTN cell C (that is, there is a possibility that the PCI of the NTN cell C will collide with another PCI). Depending on the determination, a notification including the CGI of the neighboring cell is transmitted to the base station 20A. That is, when a PCI collision occurs, the base station 20A can obtain the CGI of a neighboring cell without executing a CGI reporting procedure (for example, transmitting and receiving a Report Global-CID Request message and a Report Global-CID message). As a result, according to this embodiment, it is possible to reduce communication or processing delays in communication using NTN.

After determining that a PCI collision has occurred in step S103, the base station 20A sends a notification indicating that a PCI collision has occurred to another base station forming a neighboring cell, for example, the base station 20B, via the Xn link. Send via. That is, a notification indicating that a PCI collision has occurred is transmitted from the base station 20A to another base station 20B. The notification may be, for example, NG-RAN NODE CONFIGURATION UPDATE (step S104). After that, the base station 20B may transmit an acknowledgment of receipt of the notification received in step S104 (for example, NG-RAN NODE CONFIGURATION UPDATE ACKNOWLEDGE) to the base station 20A (step S105).

Furthermore, after it is determined in step S103 that a PCI collision has occurred, the base station 20A may transmit a notification indicating that a PCI collision has occurred via the NG link. That is, the notification may be transmitted from the base station 20A to the AMF 301 of the core network 30 via the NG link. The notification may be, for example, at least one of RAN CONFIGURATION UPDATE (step S106) and AMF CONFIGURATION UPDATE (step S108). The AMF 301 may transmit RAN CONFIGURATION UPDATE ACKNOWLEDGE to the base station 20A as a confirmation of receipt of RAN CONFIGURATION UPDATE (step S107), or may transmit AMF CONFIGURATION UPDATE ACKNOWLEDGE to base station 20A as confirmation of receipt of AMF CONFIGURATION UPDATE. (Step S109).

(Other embodiments)
The embodiments described above are intended to facilitate understanding of the present invention, and are not intended to be interpreted as limiting the present invention. The flowcharts, sequences, and elements included in the embodiments, as well as their arrangement, conditions, shapes, sizes, etc., described in the embodiments are not limited to those illustrated and can be changed as appropriate. Further, it is possible to partially replace or combine the structures shown in different embodiments.

Regarding the embodiments including the above examples, the following additional notes are further disclosed.
(Additional note 1)
a control unit that determines whether the neighboring cells include an NTN (Non-Terrestrial Network) cell that is a cell formed by a non-terrestrial base station;
a communication unit that transmits a first notification including a CGI (Cell Global Identity) of a neighboring cell to a base station in response to the control unit determining that the NTN cell is included in the neighboring cells; terminal.
(Additional note 2)
The user terminal according to supplementary note 1, wherein the control unit determines whether the NTN cell is included in neighboring cells based on a second notification received from the base station via the communication unit.
(Additional note 3)
The user terminal according to supplementary note 2, wherein the second notification includes information set based on whether or not ephemeris information is stored in the base station.
(Additional note 4)
The user terminal according to any one of Supplementary Notes 1 to 3, wherein the first notification includes a measurement report of a neighboring cell.
(Appendix 5)
The user terminal according to

appendix

2 or 3, wherein the second notification includes a system information block that includes information set based on whether or not ephemeris information is stored in the base station.
(Appendix 6)
In response to transmitting to the user terminal information set based on the fact that neighboring cells include NTN (Non-Terrestrial Network) cells, which are cells formed by non-terrestrial base stations, the user terminal a communication unit that receives a notification including PCI (Physical Cell Identity) and CGI (Cell Global Identity) of neighboring cells;
A base station comprising: a control unit that determines whether a collision has occurred between a PCI included in the notification received by the communication unit and a pre-stored PCI of a neighboring cell.
(Appendix 7)
The base station according to appendix 6, wherein in response to the control unit determining that the collision has occurred, the communication unit transmits a notification indicating that a PCI collision has occurred via an Xn link. .
(Appendix 8)
According to appendix 6 or 7, in response to the control unit determining that the collision has occurred, the communication unit transmits a notification indicating that a PCI collision has occurred via the NG link. base station.
(Appendix 9)
In an information processing device,
The control unit determines whether or not the neighboring cells include an NTN (Non-Terrestrial Network) cell that is a cell formed by non-terrestrial base stations;
In response to the control unit determining that the NTN cell is included in the neighboring cells, the communication unit may transmit a first notification including a CGI (Cell Global Identity) of the neighboring cell to the base station. wireless communication methods including;
(Appendix 10)
In an information processing device,
In response to the communication unit transmitting to the user terminal information set based on the fact that an NTN (Non-Terrestrial Network) cell, which is a cell formed by non-terrestrial base stations, is included in the neighboring cells, Receiving a notification including a PCI (Physical Cell Identity) and a CGI (Cell Global Identity) of a neighboring cell from a user terminal;
A wireless communication method comprising: a control unit determining whether a conflict has occurred between a PCI included in the notification received by the communication unit and a pre-stored PCI of a neighboring cell.
(Appendix 11)
information processing equipment,
a control unit that determines whether the neighboring cells include an NTN (Non-Terrestrial Network) cell that is a cell formed by a non-terrestrial base station;
a communication unit that transmits a first notification including a CGI (Cell Global Identity) of a neighboring cell to a base station in response to the control unit determining that the NTN cell is included in the neighboring cells; A storage medium that stores a program to function as a terminal.
(Appendix 12)
information processing equipment,
In response to transmitting to the user terminal information set based on the fact that neighboring cells include NTN (Non-Terrestrial Network) cells, which are cells formed by non-terrestrial base stations, the user terminal a communication unit that receives a notification including PCI (Physical Cell Identity) and CGI (Cell Global Identity) of neighboring cells;
a control unit that determines whether a collision has occurred between the PCI included in the notification received by the communication unit and the PCI of a neighboring cell stored in advance; a program for functioning as a base station; A storage medium that stores.

DESCRIPTION OF SYMBOLS 1... Wireless communication system, 11... Receiving section, 12... Transmitting section, 13... Storage section, 14... Measuring section, 15... Control section, 20... Base station, 21... Transmitting section, 22... Receiving section, 23... Control section , 30... Core network, A... Antenna, 10a... Processor, 10b... Memory, 10c... Storage device, 10d... Communication device, 10e... Input device, 10f... Output device

Claims

a control unit that determines whether the neighboring cells include an NTN (Non-Terrestrial Network) cell that is a cell formed by a non-terrestrial base station;
a communication unit that transmits a first notification including a CGI (Cell Global Identity) of a neighboring cell to a base station in response to the control unit determining that the NTN cell is included in the neighboring cells; terminal.
The user terminal according to claim 1, wherein the control unit determines whether the NTN cell is included in neighboring cells based on a second notification received from the base station via the communication unit.
The user terminal according to claim 2, wherein the second notification includes information set based on whether or not ephemeris information is stored in the base station.
The user terminal according to claim 1, wherein the first notification includes a measurement report of a neighboring cell.
The user terminal according to claim 2, wherein the second notification includes a system information block that includes information set based on whether or not ephemeris information is stored in the base station.
In response to transmitting to the user terminal information set based on the fact that neighboring cells include NTN (Non-Terrestrial Network) cells, which are cells formed by non-terrestrial base stations, the user terminal a communication unit that receives a notification including PCI (Physical Cell Identity) and CGI (Cell Global Identity) of neighboring cells;
A base station comprising: a control unit that determines whether a collision has occurred between a PCI included in the notification received by the communication unit and a pre-stored PCI of a neighboring cell.
The base according to claim 6, wherein in response to the control unit determining that the collision has occurred, the communication unit transmits a notification indicating that a PCI collision has occurred via an Xn link. Bureau.
The base according to claim 6, wherein in response to the control unit determining that the collision has occurred, the communication unit transmits a notification indicating that a PCI collision has occurred via an NG link. Bureau.
In an information processing device,
The control unit determines whether or not the neighboring cells include an NTN (Non-Terrestrial Network) cell that is a cell formed by non-terrestrial base stations;
In response to the control unit determining that the NTN cell is included in the neighboring cells, the communication unit may transmit a first notification including a CGI (Cell Global Identity) of the neighboring cell to the base station. wireless communication methods including;
In an information processing device,
In response to the communication unit transmitting to the user terminal information set based on the fact that an NTN (Non-Terrestrial Network) cell, which is a cell formed by non-terrestrial base stations, is included in the neighboring cells, Receiving a notification including a PCI (Physical Cell Identity) and a CGI (Cell Global Identity) of a neighboring cell from a user terminal;
A wireless communication method comprising: a control unit determining whether a conflict has occurred between a PCI included in the notification received by the communication unit and a pre-stored PCI of a neighboring cell.
information processing equipment,
a control unit that determines whether the neighboring cells include an NTN (Non-Terrestrial Network) cell that is a cell formed by a non-terrestrial base station;
a communication unit that transmits a first notification including a CGI (Cell Global Identity) of a neighboring cell to a base station in response to the control unit determining that the NTN cell is included in the neighboring cells; A storage medium that stores a program to function as a terminal.
information processing equipment,
In response to transmitting to the user terminal information set based on the fact that neighboring cells include NTN (Non-Terrestrial Network) cells, which are cells formed by non-terrestrial base stations, the user terminal a communication unit that receives a notification including PCI (Physical Cell Identity) and CGI (Cell Global Identity) of neighboring cells;
a control unit that determines whether a collision has occurred between the PCI included in the notification received by the communication unit and the PCI of a neighboring cell stored in advance; a program for functioning as a base station; A storage medium that stores.