Base station, radio terminal, communication method, and program

Abstract

An objective of the present invention is to provide a base station that can shorten a required time in which a radio terminal transmits information related to a flight status thereof. A base station according to the present disclosure comprises: a transmission unit that transmits, to instructing at least one radio terminal, instruction information for instructing the transmission of flight-related information that is related to the radio terminal in an RRC INACTIVE status; and a reception unit that receives the flight-related information in the RRC INACTIVE status from the radio terminal having received the instruction information.

Description

Base station, wireless terminal, communication method, and program

[0001] The present disclosure relates to a base station, a wireless terminal, a communication method, and a program.

[0002] In recent years, communication methods in uncrewed aerial vehicles (UAVs), which are unmanned flying terminals, and uncrewed aerial systems (UASs), which include UAV controllers, have been studied by 3GPP (registered trademark).

[0003] Communication between a UAV and a UAV controller may be referred to as C2 (Command and Control) communication. For example, Non-Patent Document 1 defines UTM (UAS Traffic Management)-Navigated C2 communication. The UTM entity performs, for example, tracking of the UAV and authentication of the UAV and UAV controller. In UTM-Navigated C2 communication, for example, the UTM entity provides a flight plan to the UAV for autonomous flight, updates the flight route, monitors the flight status of the UAV, and navigates the UAV.

[0004] Here, Non-Patent Document 2 discloses a procedure for a UAV to transmit information about its flight status. In Non-Patent Document 2, for example, when a UE (User Equipment) (corresponding to a UAV) in the RRC_IDLE state receives an RRCConnectionSetup from a base station, it transitions to the RRC_CONNECTED state and transmits an RRCConnectionSetupComplete message including flightPathInfoAvailable to the base station. This allows the base station to recognize that the UE holds information corresponding to its flight status. Next, the base station transmits a UEInformationRequest message to the UE in the RRC_CONNECTED state. The UE transmits a UEInformationResponse message, which is a response message to the received message, to the base station. At this time, if the flightPathInfoReq field is set in the UEInformationRequest message, the UE includes a flightPathInfoReport (corresponding to the flight status) in the UEInformationResponse message, which includes a list of waypoints (relay points) along the UE's flight path.

[0005] The RRC_IDLE state is a state in which the UE context is not held in the UE or the base station. The RRC_CONNECTED state is a state in which a connection between the UE and the base station is established. In addition, in 3GPP, the RRC_INACTIVE state is defined as a state between the RRC_CONNECTED state and the RRC_IDLE state. In the RRC_INACTIVE state, the UE and the base station hold the UE context, but the connection between the UE and the base station is released. Therefore, in the RRC_INACTIVE state, a power saving state can be maintained similarly to the RRC_IDLE state.

[0006] 3GPP TS 22.125 V17.6.0 (2022-03)3GPP TS 36.331 V17.0.0 (2022-03)

[0007] In the communication process disclosed in Non-Patent Document 2, a UAV must be in the RRC_CONNECTED state before transmitting information about its flight status. That is, a UE in the RRC_IDLE state or the RRC_INACTIVE state can transmit information about its flight status after transitioning to the RRC_CONNECTED state and then receiving a UEInformationRequest message with the flightPathInfoReq field set from the base station. However, transitioning to the RRC_CONNECTED state requires a certain amount of time, and after transitioning to the RRC_CONNECTED state, it also requires another certain amount of time before receiving a UEInformationRequest message with the flightPathInfoReq field set from the base station. Therefore, there is a problem in that it takes time for the UAV to transmit information related to its flight status to a UTM entity, etc.

[0008] In view of the above-mentioned problems, one of the objectives of the present disclosure is to provide a base station, a wireless terminal, a communication method, and a program that can shorten the time required for a wireless terminal to transmit information related to flight status.

[0009] A base station according to a first aspect of the present disclosure includes a transmitting unit that transmits instruction information to at least one wireless terminal instructing the wireless terminal to transmit flight-related information regarding the wireless terminal in an RRC INACTIVE state, and a receiving unit that receives the flight-related information from the wireless terminal that has received the instruction information in an RRC INACTIVE state.

[0010] A wireless terminal according to a second aspect of the present disclosure includes a receiving unit that receives instruction information from a base station instructing the wireless terminal to transmit flight-related information in an RRC INACTIVE state, and a transmitting unit that transmits the flight-related information to the base station in the RRC INACTIVE state based on the instruction information.

[0011] A communication method performed in a base station according to a third aspect of the present disclosure includes transmitting instruction information to at least one wireless terminal instructing the wireless terminal to transmit flight-related information regarding the wireless terminal in an RRC INACTIVE state, and receiving the flight-related information from the wireless terminal that has received the instruction information in an RRC INACTIVE state.

[0012] A communication method executed in a wireless terminal according to a fourth aspect of the present disclosure includes receiving instruction information from a base station instructing the wireless terminal to transmit flight-related information in an RRC INACTIVE state, and transmitting the flight-related information to the base station in the RRC INACTIVE state based on the instruction information.

[0013] A program according to a fifth aspect of the present disclosure causes a computer to transmit instruction information to at least one wireless terminal instructing the wireless terminal to transmit flight-related information related to the wireless terminal in an RRC INACTIVE state, and receive the flight-related information from the wireless terminal that has received the instruction information in an RRC INACTIVE state.

[0014] A program according to a sixth aspect of the present disclosure causes a computer to receive instruction information from a base station instructing the computer to transmit flight-related information in an RRC INACTIVE state, and to transmit the flight-related information to the base station in the RRC INACTIVE state based on the instruction information.

[0015] The present disclosure makes it possible to provide a base station, a wireless terminal, a communication method, and a program that can reduce the time required for a wireless terminal to transmit information related to flight conditions.

[0016] FIG. 1 is a configuration diagram of a base station according to the present disclosure. FIG. 2 is a configuration diagram of a wireless terminal according to the present disclosure. FIG. 3 is a diagram showing a flow of communication processing executed in a base station according to the present disclosure. FIG. 4 is a diagram showing a flow of communication processing executed in a wireless terminal according to the present disclosure. FIG. 5 is a configuration diagram of a communication system according to the present disclosure. FIG. 6 is a diagram showing a flow of broadcast information transmission processing according to the present disclosure. FIG. 7 is a diagram showing a flow of SDT processing according to the present disclosure. FIG. 8 is a configuration diagram of a base station according to the present disclosure. FIG. 9 is a configuration diagram of a wireless terminal according to the present disclosure.

[0017] (First embodiment) Hereinafter, a configuration example of a base station 10 will be described with reference to Fig. 1. The base station 10 may be a computer device that operates when a processor executes a program stored in a memory. The base station 10 may be, for example, a gNB (g Node B) defined in 3GPP (3rd Generation Partnership Project).

[0018] The base station 10 includes a transmitter 11 and a receiver 12. The transmitter 11 and receiver 12 may be software or modules that are executed by a processor executing a program stored in a memory, or may be hardware such as a circuit or a chip.

[0019] The transmitter 11 transmits instruction information to at least one wireless terminal instructing the wireless terminal to transmit flight-related information related to the wireless terminal in the RRC INACTIVE state. The wireless terminal may be, for example, a terminal whose flight operations are controlled using a controller. Alternatively, the wireless terminal may be a terminal that flies autonomously according to a predetermined flight path and flight plan. The wireless terminal may be, for example, a drone. Alternatively, the wireless terminal may be a controller that controls the flight operations of the flying terminal. Furthermore, the wireless terminal may correspond to UE, which is used as a general term for terminals in 3GPP.

[0020] The RRC INACTIVE state is a UE state defined in 3GPP. In addition to the RRC INACTIVE state, 3GPP also defines RRC IDLE state and RRC CONNECTED state as UE states. The RRC INACTIVE state is a state in which a connection between the UE and a base station is not established, and further, a state in which the base station does not schedule the UE. Scheduling may be, for example, allocating radio resources to be used by the UE for receiving downlink data or transmitting uplink data. Allocating radio resources includes determining the timing of data transmission and reception by the UE, the amount of radio resources to be used, and their location on the frequency axis.

[0021] The radio resources may be those defined in 3GPP, which defines NR (New Radio) as a wireless communication standard. 3GPP defines that one frame consists of 10 subframes. One subframe has a length of 1 ms (millisecond). Furthermore, one slot has 14 symbols in the case of normal CP, and its length varies depending on the sub-carrier spacing. For example, the sub-carrier spacing is defined as 15 kHz, 30 kHz, 60 kHz, 120 kHz, or 240 kHz. For example, when the sub-carrier spacing is 15 kHz, one subframe includes one slot. When the sub-carrier spacing is 30 kHz, one subframe includes two slots. When the sub-carrier spacing is 60 kHz, one subframe includes four slots. When the sub-carrier spacing is 120 kHz, one subframe includes eight slots. When the sub-carrier spacing is 240 kHz, one subframe includes 16 slots.

[0022] A wireless terminal is assigned radio resources, with one slot or one symbol being the smallest unit, and transmits and receives data. The radio resources may also be referred to as resource blocks. Uplink data is data that the wireless terminal transmits to the base station 10, and downlink data is data that the base station 10 transmits to the wireless terminal. The uplink data and downlink data include control data and user data. The control data may also be referred to as C (Control)-Plane data, for example, and the user data may also be referred to as U (User)-Plane data.

[0023] The flight-related information may include, for example, location information indicating the start point and finish point of the wireless terminal, and location information indicating intermediate points between the start point and the finish point. The flight-related information may also include time information indicating the arrival time at the finish point and the time of passing through each intermediate point. The flight-related information may also include information indicating the flight altitude and speed of the wireless terminal. The flight-related information may also include information indicating the remaining battery level of the wireless terminal, the size of the wireless terminal, and, if the wireless terminal is carrying an object, the size or weight of the object being carried.

[0024] The receiving unit 12 receives flight-related information from the wireless terminal that has received the instruction information in the RRC INACTIVE state. The wireless terminal transmits the flight-related information to the base station 10 in the RRC INACTIVE state without transitioning to the RRC CONNECTED state.

[0025] Next, a configuration example of the wireless terminal 20 according to the first embodiment will be described with reference to Fig. 2. The wireless terminal 20 may be a computer device that operates when a processor executes a program stored in a memory. The flight of the wireless terminal 20 may be controlled by a controller or the like via a wireless communication line. Alternatively, the flight of the wireless terminal 20 may be controlled by a server device or the like via a mobile network. Alternatively, the wireless terminal 20 may be a controller that controls the flight operation of the flying terminal.

[0026] The receiving unit 21 receives instruction information instructing the base station 10 to transmit flight-related information in the RRC INACTIVE state from the base station 10. The transmitting unit 22 transmits the flight-related information to the base station in the RRC INACTIVE state based on the instruction information.

[0027] The wireless terminal 20 may store flight-related information in advance, or may acquire the information periodically or at any time from another computer device. The other computer device may be, for example, a controller that operates the wireless terminal 20 via a wireless communication line, or a communication device or server device that communicates via a mobile network. Alternatively, the wireless terminal 20 may acquire or detect the flight-related information using a sensor or the like.

[0028] Next, a flow of communication processing executed in the base station 10 according to the first embodiment will be described with reference to Fig. 3. First, the transmitter 11 transmits instruction information to at least one wireless terminal instructing the wireless terminal to transmit flight-related information related to the wireless terminal in the RRC INACTIVE state (S11). Next, the receiver 12 receives the flight-related information from the wireless terminal that has received the instruction information in the RRC INACTIVE state (S12).

[0029] Next, a flow of communication processing executed in the wireless terminal 20 according to the first embodiment will be described with reference to Fig. 4. First, the receiver 21 receives instruction information from the base station 10 instructing the wireless terminal 20 to transmit flight-related information in the RRC INACTIVE state (S21). Next, the transmitter 22 transmits the flight-related information to the base station 10 in the RRC INACTIVE state based on the instruction information (S22).

[0030] As described above, the wireless terminal 20 according to the first embodiment transmits flight-related information to the base station 10 in the RRC INACTIVE state based on instruction information received from the base station 10. This allows the wireless terminal 20 to transmit flight-related information to the base station 10 without transitioning to the RRC CONNECTED state. As a result, the wireless terminal 20 can shorten the time it takes to transmit the flight-related information.

[0031] (Second embodiment) Next, a configuration example of a communication system according to a second embodiment will be described with reference to Fig. 5. The communication system in Fig. 5 illustrates a communication system defined by 3GPP. For example, the communication system includes a gNB 30, a UE 41, a UE 42, a UPF (User Plane Function) entity 50 (hereinafter referred to as UPF 50), and a UTM entity 60 (hereinafter referred to as UTM 60). The entities may be referred to as devices or nodes.

[0032] The gNB 30 corresponds to the base station 10 in Fig. 1. The gNB 30 is a base station that supports wireless communication using 5G (5th Generation), a wireless communication standard defined by 3GPP. The gNB 30 manages a cell, which is a communication area where wireless communication can be performed, and performs wireless communication using 5G with UE 41 and UE 42 present in the cell.

[0033] The UE 41 and the UE 42 correspond to, for example, wireless terminals. The wireless terminal may be an unmanned aerial terminal or a flight terminal that operates unmanned. The wireless terminal may be a terminal that flies autonomously. Furthermore, one of the UE 41 and the UE 42 may be a wireless terminal, and the other may be a controller that controls the operation of the wireless terminal by wirelessly communicating with the wireless terminal. The UE 41 and the UE 42 may be a UAV and a UAV controller. Specifically, the UAV may be a drone.

[0034] The UPF 50 corresponds to a core network device constituting 5GC (5G Core). The UPF 50 relays U-Plane data related to the UE 41 and the UE 42. For example, the UPF 50 may transmit U-Plane data received from the UE 41 via the gNB 30 to another UE, or may transmit U-Plane data transmitted from another UE to the UE 41 via the gNB 30.

[0035] The UTM 60 has several functions for managing the autonomous flight of the UE 41 in a certain flight area. In other words, the UTM 60 provides services for managing the flight of the UE 41 in a certain flight area. For example, the UTM 60 has functions for identifying, tracking, approving, etc. the UAV. The UTM 60 may obtain flight-related information from the UE 41 or UE 42 and manage the flight of the UE 41.

[0036] Next, a process flow for transmitting broadcast information to UE 41 according to the second embodiment will be described with reference to FIG. 6 . In FIG. 6 , the process flow for transmitting broadcast information to UE 41 is described, but broadcast information may also be transmitted to UE 42 and other UEs in the same manner. First, gNB 30 transmits or broadcasts an SIB indicating ENABLING FLIGHT PATH REPORTING WITH SDT to all UEs present in a cell managed by gNB 30, including UE 41 (S31). gNB 30 transmits a Master Information Block (MIB) via a Physical Broadcast Channel (PBCH) to all UEs present in a cell managed by gNB 30. Parameters for monitoring the PDCCH are set in the MIB. Monitoring the PDCCH may be rephrased as detecting or identifying the PDCCH. Scheduling information related to a PDSCH in which an SIB is configured is set in the PDCCH. A PDSCH in which an SIB is configured may be rephrased as a PDSCH including an SIB. That is, by receiving the MIB via the PBCH, the UE 41 is able to identify the radio resource in which the SIB is set, and receives the SIB.

[0037] ENABLING FLIGHT PATH REPORTING WITH SDT is information instructing the UE to transmit flight path information using SDT (Small Data Transmission). The flight path information may also be referred to as a flight path report. ENABLING FLIGHT PATH REPORTING WITH SDT is set in an SIB or is included in an SIB and transmitted. ENABLING FLIGHT PATH REPORTING WITH SDT may be set in an SIB whose use is already defined in 3GPP, or may be set in a newly defined SIB. SDT is a procedure that allows a UE to transmit data in an RRC INACTIVE state or enables the UE to transmit data in an RRC INACTIVE state. The UE can transmit uplink data using SDT when the amount or size of uplink data to be transmitted to the gNB 30 is less than or equal to a predetermined value. In other words, the UE can start SDT when the amount or size of uplink data stored in a buffer for transmitting uplink data is less than or equal to a predetermined value. Uplink data whose amount or size is less than or smaller than a predetermined value may be referred to as small data.

[0038] Flight Path Reporting may be a state in which UE 41 transmits flight path information to gNB 30 when UE 41 is capable of transmitting flight path information to gNB 30. Being capable of transmitting flight path information to gNB 30 may mean that UE 41 has the function of transmitting flight path information to gNB 30, or may further mean that UE 41 holds flight path information.

[0039] The flight path information may include, for example, information regarding the maximum number of relay points that the UE 41 passes through on the way to the destination and the timing of passing through the relay points. The flight path information may also include information indicating the positions of the relay points. The timing of passing through the relay points may be indicated using, for example, a timestamp.

[0040] The SIB in which ENABLING FLIGHT PATH REPORTING WITH SDT is set may be set with information regarding the timing at which the UE 41 reports flight path information. The timing at which the flight path information is reported may be periodic or may be any timing set by the gNB 30.

[0041] Furthermore, a threshold for the data amount or data size of flight path information stored in a buffer by the UE 41 may be set in the SIB in which ENABLING FLIGHT PATH REPORTING WITH SDT is set. For example, when the data amount or data size of the flight path information stored in the buffer reaches the threshold, the UE 41 may start processing related to the SDT to transmit the flight path information to the gNB 30. A value different from the threshold for the data amount or data size of the flight path information may be set.

[0042] Next, the flow of SDT processing according to the second embodiment will be described with reference to FIG. 7. FIG. 7 shows the procedure of RA (Random Access) based SDT using the Random Access Procedure. In FIG. 7, it is assumed that the UE 41 has received ENABLING FLIGHT PATH REPORTING WITH SDT set in the SIB. It is also assumed that the UE 41 is in an RRC INACTIVE state and a CM-CONNECTED state. The CM-CONNECTED state is a state in which a NAS signaling connection is established between the UE 41 and an AMF (Access and Mobility Management Function) entity (not shown), which is a core network device. In addition, the gNB 30 in FIG. 7 may be a gNB different from the gNB with which the UE 41 previously communicated (the last serving gNB). The gNB with which the UE 41 currently communicates may be referred to as the receiving gNB.

[0043] First, the UE 41 transmits an RRC Resume Request to the gNB 30 together with at least one of SDT data and SDT signaling by a Random Access Procedure (S41). Here, the UE 41 may transmit the RRC Resume Request to the gNB 30 by executing, for example, a 4-step RA (Random Access) type or a 2-step RA type Random Access Procedure. Specifically, the UE 41 transmits a preamble to the gNB 30 as MSG1 (Message 1) by a PRACH (Physical Random Access Channel). Upon receiving a response to MSG1 (random access response), the UE 41 transmits MSG3 (Message 3) to the gNB 30 in accordance with an UL (Uplink) grant scheduled in the random access response. The UL grant may indicate, for example, the timing and radio resources for the gNB 30 to transmit uplink data.

[0044] The UE 41 may transmit an RRC Resume Request with SDT data to the gNB 30 as MSG3. Here, the SDT data transmitted by the UE 41 in MSG3 may be flight path information. The flight path information may also be transmitted in an SRB (Signaling Radio Bearer) established or configured between the UE 41 and the gNB 30. The SRB is an RB for transmitting RRC messages and a NAS (Non Access Stratum). In 3GPP, SRB0 to SRB4 are defined as SRBs. For example, flight path information may be transmitted in SRB2. The SRB2 is an SRB used for transmitting an RRC message including logged measurement information.

[0045] Next, the gNB 30 determines to maintain the RRC INACTIVE state for SDT (S42). Before step S42, the gNB 30 may have obtained the UE context for the UE 41 from the last serving gNB.

[0046] Next, the gNB 30 transmits the UL small data to the UPF 50 (S43). The UL small data corresponds to the SDT data transmitted from the UE 41 to the gNB 30, and specifically corresponds to flight path information. The UL small data may be, for example, uplink data that is less than or smaller than a predetermined data amount or data size. The flight path information is transmitted to the UTM 60 via the UPF 50.

[0047] Next, the gNB 30 determines to terminate the SDT by transmitting the UL small data (S44). Next, the gNB 30 transmits an RRC Release message to the UE 41 (S45). The RRC Release message includes a Suspend indication indicating that the UE 41 is to transition to the RRC INACTIVE state. For example, if the UE 41 is to transmit uplink data that does not correspond to UL small data or uplink data that is not subject to the SDT, the UE 41 may transmit the data after transitioning to the RRC CONNECTED state. When the UE 41 transitions to the RRC CONNECTED state in this way, it transitions to the RRC INACTIVE state upon receiving an RRC Release message including a Suspend indication. When the UE 41 receives an RRC Release message including a Suspend indication (or a Suspend configuration) in the RRC INACTIVE state, the UE 41 maintains the RRC INACTIVE state.

[0048] As described above, the gNB 30 according to the second embodiment broadcasts an SIB in which ENABLING FLIGHT PATH REPORTING WITH SDT is set, and the UE 41 can transmit flight path information using the SDT. By transmitting the flight path information using the SDT, the UE 41 does not need to transition from the RRC INACTIVE state to the RRC CONNECTED state in order to transmit the flight path information. As a result, the UE 41 can shorten the time from when it becomes necessary to transmit flight path information to when it actually transmits the flight path information.

[0049] (Embodiment 3) Subsequently, a description will be given of a notification process of ENABLING FLIGHT PATH REPORTING WITH SDT according to embodiment 3. In embodiment 2, an example has been described in which ENABLING FLIGHT PATH REPORTING WITH SDT is set in the SIB, and ENABLING FLIGHT PATH REPORTING WITH SDT is broadcast to all UEs present in a cell managed by the gNB 30.

[0050] Here, in the third embodiment, an example will be described in which ENABLING FLIGHT PATH REPORTING WITH SDT is notified for each UE.

[0051] For example, the gNB 30 may notify the UE 41 of ENABLING FLIGHT PATH REPORTING WITH SDT by setting ENABLING FLIGHT PATH REPORTING WITH SDT in the RRC Release message shown in Fig. 7. Specifically, the gNB 30 may set ENABLING FLIGHT PATH REPORTING WITH SDT in the RRC Release message including the Suspend indication.

[0052] By setting ENABLING FLIGHT PATH REPORTING WITH SDT in an RRC Release message containing a Suspend indication that is sent to a specific UE, it is possible to instruct the specific UE to use SDT for transmitting flight path information.

[0053] In addition to the SDT procedure in FIG. 7 , for example, ENABLING FLIGHT PATH REPORTING WITH SDT may be set in an RRC Release message including a Suspend indication transmitted in a Radio Access Network based notification area (RNA) update. The gNB 30 manages the RNA as location information of a UE in the RRC INACTIVE state. The RNA is an area covering one or more cells, and may be an area included in a registration area managed by the core network. The UE 41 may perform an RNA update, for example, when it moves to an area different from the currently set RNA, or periodically. At this time, the UE 41 transmits an RRCResumeRequest to the gNB 30, similar to the procedure shown in FIG. 7 , and receives an RRC Release message including a Suspend indication.

[0054] Furthermore, when the UE 41 in the RRC INACTIVE state transitions to the RRC CONNECTED state, it transmits an RRC Resume Request to the gNB 30. At this time, the UE 41 transitions to the RRC CONNECTED state by receiving an RRC Resume from the gNB 30 as a response to the RRC Resume Request. After transitioning to the RRC CONNECTED state, the UE 41 transitions to the RRC INACTIVE state by receiving an RRC Release message including a Suspend indication from the gNB 30. ENABLING FLIGHT PATH REPORTING WITH SDT may be set in the RRC Release message including a Suspend indication that is transmitted to transition the UE in the RRC CONNECTED state to the RRC INACTIVE state.

[0055] The UE 41, which has received an RRC Release message including a Suspend indication in which ENABLING FLIGHT PATH REPORTING WITH SDT is set, transmits flight path information to the gNB 30 by using the SDT, similar to the procedure described in Fig. 7. That is, the UE 41 may transmit flight path information to the gNB 30 by using the RA based SDT.

[0056] Alternatively, the gNB 30 may set a UL grant indicating resources for transmitting flight path information in an RRC Release message. The UE 41 that has received the RRC Release message including the UL grant transmits the flight path information to the gNB 30 using the SDT. The procedure in which the UE 41 performs communication using the SDT based on the UL grant may be referred to as a CG (Configured Grant) based SDT.

[0057] For example, in an RRC Release message including a Suspend indication in which ENABLING FLIGHT PATH REPORTING WITH SDT is set, it may be indicated whether UE 41 uses RA-based SDT or CG-based SDT.

[0058] As described above, the gNB 30 according to the third embodiment transmits an RRC Release message including a Suspend indication in which ENABLING FLIGHT PATH REPORTING WITH SDT is set for each UE. This makes it possible to reduce the amount of information set in the SIB compared to the second embodiment.

[0059] Here, for example, the gNB 30 may broadcast an SIB in which ENABLING FLIGHT PATH REPORTING WITH SDT is set, and may transmit, for each UE, information regarding the timing at which the UE 41 reports flight path information, using an RRC Release message. Furthermore, the gNB 30 may transmit, for each UE, the data amount or data size threshold of the flight path information that the UE 41 stores in a buffer, using an RRC Release message.

[0060] FIG. 8 is a block diagram showing an example configuration of a base station 10 and a gNB 30 (hereinafter referred to as the base station 10, etc.). Referring to FIG. 8, the base station 10, etc. includes an RF transceiver 1001, a network interface 1003, a processor 1004, and a memory 1005. The RF transceiver 1001 performs analog RF signal processing to communicate with UEs. The RF transceiver 1001 may include multiple transceivers. The RF transceiver 1001 is coupled to an antenna 1002 and a processor 1004. The RF transceiver 1001 receives modulation symbol data (or OFDM symbol data) from the processor 1004, generates a transmit RF signal, and provides the transmit RF signal to the antenna 1002. The RF transceiver 1001 also generates a baseband receive signal based on the receive RF signal received by the antenna 1002 and provides the baseband receive signal to the processor 1004.

[0061] The network interface 1003 is used to communicate with network nodes (e.g., other core network nodes) and may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

[0062] The processor 1004 performs data plane processing and control plane processing, including digital baseband signal processing for wireless communication.

[0063] The processor 1004 may include multiple processors. For example, the processor 1004 may include a modem processor (e.g., DSP) that performs digital baseband signal processing and a protocol stack processor (e.g., CPU or MPU) that performs control plane processing.

[0064] The memory 1005 is configured by a combination of volatile memory and non-volatile memory. The memory 1005 may include multiple physically independent memory devices. The volatile memory may be, for example, static random access memory (SRAM), dynamic RAM (DRAM), or a combination thereof. The non-volatile memory may be mask read only memory (MROM), electrically erasable programmable ROM (EEPROM), flash memory, a hard disk drive, or any combination thereof. The memory 1005 may include storage located remotely from the processor 1004. In this case, the processor 1004 may access the memory 1005 via the network interface 1003 or an I / O interface (not shown).

[0065] The memory 1005 may store software modules (computer programs) including instructions and data for performing processing by the base station 10, etc., described in the above-described embodiments. In some implementations, the processor 1004 may be configured to read and execute the software modules from the memory 1005, thereby performing processing by the base station 10, etc., described in the above-described embodiments.

[0066] FIG. 9 is a block diagram showing an example configuration of a wireless terminal 20 and a UE 41 (hereinafter referred to as wireless terminal 20, etc.). A radio frequency (RF) transceiver 1101 performs analog RF signal processing to communicate with an access network node 20 or a gNB 30. The analog RF signal processing performed by the RF transceiver 1101 includes frequency up-conversion, frequency down-conversion, and amplification. The RF transceiver 1101 is coupled to an antenna 1102 and a baseband processor 1103. That is, the RF transceiver 1101 receives modulation symbol data (or OFDM symbol data) from the baseband processor 1103, generates a transmit RF signal, and provides the transmit RF signal to the antenna 1102. The RF transceiver 1101 also generates a baseband receive signal based on the receive RF signal received by the antenna 1102 and provides it to the baseband processor 1103.

[0067] The baseband processor 1103 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. Digital baseband signal processing includes (a) data compression / decompression, (b) data segmentation / concatenation, (c) transmission format (transmission frame) generation / decomposition, (d) transmission path coding / decoding, (e) modulation (symbol mapping) / demodulation, and (f) generation of OFDM symbol data (baseband OFDM signal) using Inverse Fast Fourier Transform (IFFT). Meanwhile, control plane processing includes communication management for Layer 1, Layer 2, and Layer 3.

[0068] The baseband processor 1103 may include a modem processor (e.g., a Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., a Central Processing Unit (CPU) or a Micro Processing Unit (MPU)) that performs control plane processing. In this case, the protocol stack processor that performs control plane processing may be shared with the application processor 1104, which will be described later.

[0069] The application processor 1104 is also referred to as a CPU, MPU, microprocessor, or processor core. The application processor 1104 may include multiple processors (multiple processor cores). The application processor 1104 executes a system software program (operating system (OS)) and various application programs (e.g., a calling application, a web browser, a mailer, a camera operation application, and a music playback application) read from the memory 1106 or a memory not shown, thereby realizing various functions of the wireless terminal 20, etc.

[0070] In some implementations, the baseband processor 1103 and the application processor 1104 may be integrated on a single chip, as indicated by the dashed line (1105) in Figure 9. In other words, the baseband processor 1103 and the application processor 1104 may be implemented as a single System on Chip (SoC) device 1105. An SoC device may also be called a system Large Scale Integration (LSI) or chipset.

[0071] The memory 1106 is volatile memory, nonvolatile memory, or a combination thereof. The memory 1106 may include multiple physically independent memory devices. Volatile memory is, for example, static random access memory (SRAM), dynamic RAM (DRAM), or a combination thereof. Nonvolatile memory is, for example, mask read only memory (MROM), electrically erasable programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. For example, the memory 1106 may include an external memory device accessible from the baseband processor 1103, the application processor 1104, and the SoC 1105. The memory 1106 may also include an internal memory device integrated within the baseband processor 1103, the application processor 1104, or the SoC 1105. Furthermore, the memory 1106 may include memory within a Universal Integrated Circuit Card (UICC).

[0072] The memory 1106 may store software modules (computer programs) including instructions and data for performing processing by the wireless terminal 20, etc., described in the above-described embodiments. In some implementations, the baseband processor 1103 or the application processor 1104 may be configured to read and execute the software modules from the memory 1106, thereby performing processing by the wireless terminal 20, etc., described in the above-described embodiments.

[0073] In the above examples, the program includes instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions described in the embodiments. The program may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disc (DVD), Blu-ray disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0074] The technical ideas of the present disclosure are not limited to the above-described embodiments, and can be modified as appropriate within the scope of the gist of the present disclosure.

[0075] Some or all of the above embodiments can be described as, but are not limited to, the following supplementary notes. (Supplementary Note 1) A base station comprising: a transmitter that transmits, to at least one wireless terminal, instruction information instructing the wireless terminal to transmit flight-related information related to the wireless terminal in an RRC INACTIVE state; and a receiver that receives, in an RRC INACTIVE state, the flight-related information from the wireless terminal that has received the instruction information. (Supplementary Note 2) The base station according to Supplementary Note 1, wherein the receiver receives the flight-related information transmitted using SDT (Small Data Transmission). (Supplementary Note 3) The base station according to Supplementary Note 1 or 2, wherein the transmitter broadcasts the instruction information to all the wireless terminals present in a cell managed by the base station. (Supplementary Note 4) The base station according to Supplementary Note 1 or 2, wherein the transmitter designates a specific wireless terminal and transmits the instruction information. (Supplementary Note 5) The base station according to Supplementary Note 4, wherein the transmitter transmits state instruction information to the wireless terminal in an RRC ACTIVE state, instructing the wireless terminal to transition to the RRC INACTIVE state, the state instruction information including the instruction information. (Supplementary Note 6) The base station according to any one of Supplements 1 to 5, wherein the instruction information includes information instructing the wireless terminal to transmit the flight-related information. (Supplementary Note 7) The base station according to any one of Supplements 1 to 6, wherein the instruction information includes information related to a threshold related to the data amount of the flight-related information held by the wireless terminal, and the wireless terminal transmits the flight-related information to the base station when the data amount of the flight-related information held by the wireless terminal reaches the threshold. (Supplementary Note 8) A wireless terminal comprising: a receiver that receives, from a base station, instruction information instructing the wireless terminal to transmit flight-related information in an RRC INACTIVE state; and a transmitter that transmits the flight-related information to the base station in the RRC INACTIVE state based on the instruction information. (Supplementary Note 9) The wireless terminal according to Supplementary Note 8, wherein the transmitter transmits the flight-related information to the base station using SDT (Small Data Transmission).(Supplementary Note 10) The wireless terminal according to Supplementary Note 8 or 9, wherein the instruction information includes information instructing the wireless terminal when to transmit the flight-related information. (Supplementary Note 11) The wireless terminal according to any one of Supplementary Notes 8 to 10, wherein the instruction information includes information related to a threshold related to the data volume of the flight-related information held by the wireless terminal, and wherein the transmitter transmits the flight-related information to the base station when the data volume of the flight-related information held reaches the threshold. (Supplementary Note 12) A communication method executed in a base station, comprising: transmitting, to at least one wireless terminal, instruction information instructing the wireless terminal to transmit flight-related information related to the wireless terminal in an RRC INACTIVE state; and receiving, in the RRC INACTIVE state, the flight-related information from the wireless terminal that has received the instruction information. (Supplementary Note 13) The communication method according to Supplementary Note 12, wherein, when receiving the flight-related information, the flight-related information transmitted using SDT (Small Data Transmission) is received. (Supplementary note 14) The communication method according to Supplementary note 12 or 13, wherein, when transmitting the instruction information, the instruction information is broadcast to all the wireless terminals present in a cell managed by the base station. (Supplementary note 15) The communication method according to Supplementary note 12 or 13, wherein, when transmitting the instruction information, a specific wireless terminal is designated and the instruction information is transmitted. (Supplementary note 16) The communication method according to Supplementary note 15, when transmitting the instruction information, state instruction information is transmitted to the wireless terminal in an RRC ACTIVE state, instructing the wireless terminal to transition to the RRC INACTIVE state, the state instruction information including the instruction information. (Supplementary note 17) The communication method according to any one of Supplements 12 to 16, wherein the instruction information has information instructing the wireless terminal to transmit the flight-related information. (Appendix 18) The communication method described in any one of Appendices 12 to 17, wherein the instruction information includes information regarding a threshold regarding the amount of data of the flight-related information held by the wireless terminal, and the wireless terminal transmits the flight-related information to the base station when the amount of data of the flight-related information held by the wireless terminal reaches the threshold.(Supplementary Note 19) A communication method executed in a wireless terminal, receiving, from a base station, instruction information instructing the wireless terminal to transmit flight-related information in an RRC INACTIVE state, and transmitting the flight-related information to the base station in the RRC INACTIVE state based on the instruction information. (Supplementary Note 20) The communication method described in Supplementary Note 19, wherein, when transmitting the flight-related information, the flight-related information is transmitted to the base station using SDT (Small Data Transmission). (Supplementary Note 21) The communication method described in Supplementary Note 19 or 20, wherein the instruction information includes information instructing the timing at which the wireless terminal is to transmit the flight-related information. (Supplementary Note 22) The communication method described in any one of Supplements 19 to 21, wherein the instruction information includes information related to a threshold related to the data volume of the flight-related information held by the wireless terminal, and when transmitting the flight-related information, the flight-related information is transmitted to the base station if the data volume of the flight-related information held reaches the threshold. (Supplementary Note 23) A program causing a computer to execute the following: transmitting, to at least one wireless terminal, instruction information instructing the wireless terminal to transmit flight-related information related to the wireless terminal in an RRC INACTIVE state, and receiving, in an RRC INACTIVE state, the flight-related information from the wireless terminal that has received the instruction information. (Supplementary Note 24) The program according to Supplementary Note 23, causing a computer to execute the following: when receiving the flight-related information, receive the flight-related information transmitted using SDT (Small Data Transmission). (Supplementary Note 25) The program according to Supplementary Note 23 or 24, causing a computer to execute the following: when transmitting the instruction information, broadcast the instruction information to all the wireless terminals present in a cell managed by the base station. (Supplementary Note 26) The program according to Supplementary Note 23 or 24, causing a computer to execute the following: when transmitting the instruction information, designate a specific wireless terminal and transmit the instruction information.(Supplementary Note 27) The program of Supplementary Note 26, causing a computer to execute the following: when transmitting the instruction information, transmit state instruction information to the wireless terminal in an RRC ACTIVE state, instructing the wireless terminal to transition to the RRC INACTIVE state, the state instruction information including the instruction information. (Supplementary Note 28) The program of any one of Supplements 23 to 27, wherein the instruction information includes information instructing the wireless terminal to transmit the flight-related information. (Supplementary Note 29) The program of any one of Supplements 23 to 28, wherein the instruction information includes information related to a threshold related to the data amount of the flight-related information held by the wireless terminal, and the wireless terminal transmits the flight-related information to the base station when the data amount of the flight-related information held by the wireless terminal reaches the threshold. (Supplementary Note 30) A program causing a computer to execute the following: receive, from a base station, instruction information instructing the wireless terminal to transmit flight-related information in an RRC INACTIVE state; and transmit the flight-related information to the base station in the RRC INACTIVE state based on the instruction information. (Supplementary Note 31) The program according to Supplementary Note 30, which causes a computer to execute the following: when transmitting the flight-related information, transmit the flight-related information to the base station using SDT (Small Data Transmission). (Supplementary Note 32) The program according to Supplementary Note 30 or 31, wherein the instruction information includes information instructing the timing at which the wireless terminal is to transmit the flight-related information. (Supplementary Note 33) The program according to any one of Supplements 30 to 32, which causes a computer to execute the following: when transmitting the flight-related information, the instruction information includes information related to a threshold value related to the amount of data of the flight-related information held by the wireless terminal, if the amount of data of the flight-related information held reaches the threshold value, the flight-related information is transmitted to the base station.

[0076] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0077] Each drawing is merely an example for describing one or more embodiments. Each drawing may not relate to only one particular embodiment, but may also relate to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessary to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0078] This application claims priority based on Japanese Patent Application No. 2022-122191, filed on July 29, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0079] 10 Base station 11 Transmitter 12 Receiver 20 Wireless terminal 21 Receiver 22 Transmitter 30 gNB 41 UE 42 UE 50 UPF 60 UTM

Claims

1. A transmitting means for transmitting, to at least one wireless terminal, instruction information instructing the wireless terminal to transmit flight-related information related to the wireless terminal in an RRC INACTIVE state; A base station comprising: a receiving means for receiving the flight-related information from the wireless terminal that has received the instruction information in an RRC INACTIVE state.

2. The transmitting means is The base station according to claim 1 , further comprising: transmitting, to the radio terminal in an RRC ACTIVE state, state instruction information instructing the radio terminal to transition to the RRC INACTIVE state, the state instruction information including the instruction information.

3. A receiving means for receiving instruction information from a base station instructing the transmission of flight-related information in an RRC INACTIVE state; A wireless terminal comprising: a transmitting means for transmitting the flight-related information to the base station in an RRC INACTIVE state based on the instruction information.

4. The transmitting means is The wireless terminal of claim 3 , wherein the wireless terminal transmits the flight-related information to the base station using Small Data Transmission (SDT).

5. The instruction information is 5. The wireless terminal of claim 3, further comprising information indicating when the wireless terminal is to transmit the flight-related information.

6. The instruction information is The wireless terminal has information regarding a threshold regarding the amount of data of the flight-related information held by the wireless terminal, The transmitting means is A wireless terminal as described in claim 3 or 4, which transmits the flight-related information to the base station when the data amount of the flight-related information held by the wireless terminal reaches the threshold value.

7. transmitting instruction information to at least one wireless terminal instructing the wireless terminal to transmit flight-related information related to the wireless terminal in an RRC INACTIVE state; A communication method executed in a base station, which receives the flight-related information from the wireless terminal that has received the instruction information in an RRC INACTIVE state.

8. receiving instruction information from a base station instructing the base station to transmit flight-related information in an RRC INACTIVE state; A communication method executed in a wireless terminal, the method transmitting the flight-related information to the base station in an RRC INACTIVE state based on the instruction information.

9. transmitting instruction information to at least one wireless terminal instructing the wireless terminal to transmit flight-related information related to the wireless terminal in an RRC INACTIVE state; A program that causes a computer to execute the following: receiving the flight-related information from the wireless terminal that received the instruction information in an RRC INACTIVE state.

10. receiving instruction information from a base station instructing the base station to transmit flight-related information in an RRC INACTIVE state; A program that causes a computer to execute the following: transmitting the flight-related information to the base station in an RRC INACTIVE state based on the instruction information.