Communication device, base station, and communication method

Abstract

A communication device (100) according to an embodiment comprises: a reception unit (112) that receives, from a base station (200), a radio resource control (RRC) reconfiguration message including information for setting a distance threshold for triggering notification of update of route information on the basis of distance, and a time threshold for triggering notification of update of the route information on the basis of time; and a transmission unit (111) that, in response to reception of the RRC reconfiguration message, transmits to the base station an RRC reconfiguration complete message including information indicating that the route information is available. The transmission unit transmits, to the base station on the basis of a determination based on the distance threshold and regardless of the setting of the time threshold, a UE auxiliary information message including information indicating that the route information is available.

Description

Communication device, base station, and communication method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of priority from patent application serial number 2023-114678, filed July 12, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a communication device, a base station, and a communication method used in a mobile communication system.

[0003] Release 17 of the technical specifications (TS) for the fourth generation system (4G / LTE: Long Term Evolution) defined by 3GPP (registered trademark; the same applies hereinafter) (3rd Generation Partnership Project), a standardization project for mobile communication systems, specifies that when a communication device has available path information (specifically, flight path information), the communication device includes availability information (specifically, flightPathInfoAvailable) in a radio resource control (RRC) message (e.g., an RRC connection reconfiguration complete message) transmitted in response to an RRC message from a base station. A base station that receives the availability information can obtain the path information from the communication device by requesting the path information from the communication device.

[0004] In recent years, with regard to New Radio (NR), there has been discussion about the behavior when route information is updated in a communication device after the communication device reports the route information to a base station. Currently, it is agreed that a network can configure a communication device to trigger a route information update notification (flightpath update notification) based on a set distance difference (e.g., spatial difference) or a set time difference when a timestamp is set to be reported (see, for example, Non-Patent Document 1). A base station that receives the update notification can obtain the updated route information from the communication device by requesting the route information from the communication device.

[0005] 3GPP TSG-RAN WG2 Meeting #122, R2-2306543, “Report from Session on NES, UAV, Rel-15-17 UP, Rel-17 Small Data, IIoT / URLLC, and RACH partitioning”

[0006] A communication device according to a first aspect includes: a receiver that receives a Radio Resource Control (RRC) reconfiguration message from a base station, the RRC reconfiguration message including information for setting a distance threshold for triggering notification of a route information update based on distance and a time threshold for triggering notification of the route information update based on time; and a transmitter that transmits an RRC reconfiguration complete message to the base station in response to receiving the RRC reconfiguration message, the RRC reconfiguration complete message including information indicating that the route information is available. The receiver receives a UE information request message from the base station, the RRC reconfiguration complete message including setting information for reporting the route information. The transmitter transmits a UE information response message to the base station in response to receiving the UE information request message, the UE information response message including the route information. The transmitter transmits a UE assistance information message to the base station, the UE assistance information message including information indicating that the route information is available, based on a determination based on the distance threshold, regardless of the setting of the time threshold.

[0007] A base station according to a second aspect includes: a transmitter that transmits a radio resource control (RRC) reconfiguration message to a communication device, the RRC reconfiguration message including information for setting a distance threshold for triggering notification of a route information update based on distance and a time threshold for triggering notification of the route information update based on time; and a receiver that receives an RRC reconfiguration complete message from the communication device in response to transmission of the RRC reconfiguration message, the RRC reconfiguration complete message including information indicating that the route information is available. The transmitter transmits a UE information request message to the communication device, the RRC reconfiguration complete message including setting information for reporting the route information. The receiver receives a UE information response message from the communication device, the UE information response message including the route information. The receiver receives a UE assistance information message from the communication device, the UE assistance information message including information indicating that the route information is available and based on a determination based on the distance threshold, regardless of the setting of the time threshold.

[0008] A communication method according to a third aspect is a communication method executed by a communication device, the communication method comprising: receiving, from a base station, a Radio Resource Control (RRC) reconfiguration message including information for setting a distance threshold for triggering a notification of a route information update based on distance and a time threshold for triggering the notification of the route information update based on time, transmitting, in response to receiving the RRC reconfiguration message, an RRC reconfiguration complete message including information indicating that the route information is available to the base station, receiving, from the base station, a UE information request message including setting information for reporting the route information, transmitting, in response to receiving the UE information request message, a UE information response message including the route information to the base station, and transmitting, to the base station, a UE assistance information message including information indicating that the route information is available based on a determination based on the distance threshold, regardless of the setting of the time threshold.

[0009] Objects, features, advantages, etc. of the present disclosure will become clearer from the following detailed description with reference to the accompanying drawings. FIG. 1 is a diagram illustrating a configuration of a mobile communication system according to an embodiment. FIG. 2 is a diagram illustrating an example configuration of a protocol stack according to an embodiment. FIG. 3 is a sequence diagram illustrating an assumed scenario. FIG. 4 is a diagram illustrating a configuration of a UE according to an embodiment. FIG. 5 is a diagram illustrating a configuration of a base station according to an embodiment. FIG. 6 is a sequence diagram (part 1) illustrating an example operation according to an embodiment. FIG. 7 is a diagram illustrating an example of information elements according to an example operation according to an embodiment. FIG. 8 is a sequence diagram (part 2) illustrating an example operation according to an embodiment. FIG. 9 is a sequence diagram illustrating a first example operation related to determining an update notification according to an embodiment. FIG. 10 is a sequence diagram illustrating a second example operation related to determining an update notification according to an embodiment. FIG. 11 is a sequence diagram illustrating a third example operation related to determining an update notification according to an embodiment.

[0010] A mobile communication system according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0011] The current discussion only mentions that the condition that triggers notification of route information updates is a set distance difference or time difference, which raises concerns that communication devices may not be able to notify route information updates at the appropriate time.

[0012] Therefore, an object of the present disclosure is to provide a communication device, a base station, and a communication method that are capable of notifying updates to route information at appropriate timing.

[0013] (System Configuration) First, the configuration of a mobile communication system 1 according to this embodiment will be described with reference to Fig. 1. The mobile communication system 1 is, for example, a system that complies with the 3GPP Technical Specification (TS). In the following, the mobile communication system 1 will be described using as an example a 5th Generation System (5G system) of the 3GPP standard, i.e., a mobile communication system based on NR (NR (New Radio) Radio Access).

[0014] The mobile communication system 1 includes a network 10 and a user equipment (UE) 100 that communicates with the network 10. The network 10 includes a next generation radio access network (NG-RAN) 20, which is a 5G radio access network, and a 5G core network (5GC) 30, which is a 5G core network.

[0015] The UE 100 is an example of a communication device. The UE 100 may be a mobile wireless communication device. The UE 100 may be a communication device that communicates via a base station 200. The UE 100 may be a device used by a user. The UE 100 may be a user device defined in the 3GPP technical specifications. The UE 100 is a mobile device, such as a mobile phone terminal such as a smartphone, a tablet terminal, a notebook PC, a communication module, or a communication card. The UE 100 may be a vehicle (e.g., a car, a train, etc.) or a device provided therein. The UE 100 may be a transport vehicle other than a vehicle (e.g., a ship, an airplane, etc.) or a device provided therein. The UE 100 may be a sensor or a device provided therein. Note that UE 100 may be referred to by other names such as terminal, terminal device, mobile station, mobile terminal, mobile device, mobile unit, subscriber station, subscriber terminal, subscriber device, subscriber unit, wireless station, wireless terminal, wireless device, wireless unit, remote station, remote terminal, remote device, or remote unit. Also, UE 100 is an example of a terminal, and terminals may include factory equipment, etc.

[0016] The UE 100 (i.e., the communication device) may be an unmanned aerial vehicle (UAV) or a communication module mounted on a UAV. Note that this embodiment may be applied not only to UAVs, but also to any vehicle, such as a manned or unmanned vehicle, an autonomous vehicle / semi-autonomous vehicle, a ship, an autonomous ship / semi-autonomous ship, etc. In other words, this embodiment can be applied to any vehicle including the above vehicles.

[0017] The NG-RAN 20 includes multiple base stations 200. Each base station 200 manages at least one cell. A cell constitutes the smallest unit of a communication area. One cell belongs to one frequency (carrier frequency). The term "cell" may refer to wireless communication resources or to the communication target of the UE 100. Each base station 200 can perform wireless communication with the UE 100 located in its own cell. The base station 200 communicates with the UE 100 using a RAN protocol stack. Details of the protocol stack will be described later. The base station 200 is also connected to other base stations 200 (which may be referred to as neighboring base stations) via an Xn interface. The base station 200 communicates with neighboring base stations via the Xn interface. The base station 200 provides NR user plane and control plane protocol termination for the UE 100 and is connected to the 5GC 30 via an NG interface. Such an NR base station 200 is sometimes referred to as a gNodeB (gNB). The operation of the base station 200 may be replaced with the operation of the network 10 .

[0018] The 5GC 30 includes a core network device 300. The core network device 300 includes, for example, an AMF (Access and Mobility Management Function) and / or a UPF (User Plane Function). The AMF performs mobility management for the UE 100. The UPF provides functions specialized for U-plane processing. The AMF and the UPF are connected to the base station 200 via an NG interface.

[0019] (Configuration Example of Protocol Stack) Next, a configuration example of a protocol stack according to this embodiment will be described with reference to FIG.

[0020] The protocol of the wireless section between UE 100 and base station 200 includes a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a radio resource control (RRC) layer.

[0021] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the base station 200 via a physical channel.

[0022] The MAC layer performs data priority control, retransmission processing using Hybrid ARQ (HARQ), random access procedures, etc. Data and control information are transmitted between the MAC layer of UE 100 and the MAC layer of base station 200 via a transport channel. The MAC layer of base station 200 includes a scheduler. The scheduler determines the uplink and downlink transport format (transport block size, modulation and coding scheme (MCS)) and the resources to be allocated to UE 100.

[0023] The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and the PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the base station 200 via logical channels.

[0024] The PDCP layer performs header compression / decompression and encryption / decryption.

[0025] A Service Data Adaptation Protocol (SDAP) layer may be provided as an upper layer above the PDCP layer. The SDAP layer maps IP flows, which are units for Quality of Service (QoS) control by the core network, to radio bearers, which are units for QoS control by an Access Stratum (AS).

[0026] The RRC layer controls logical channels, transport channels, and physical channels according to the establishment, re-establishment, and release of radio bearers. RRC signaling for various settings is transmitted between the RRC layer of the UE 100 and the RRC layer of the base station 200. When an RRC connection exists between the RRC of the UE 100 and the RRC of the base station 200, the UE 100 is in an RRC connected state. When there is no RRC connection between the RRC of the UE 100 and the RRC of the base station 200, the UE 100 is in an RRC idle state. When the RRC connection between the RRC of the UE 100 and the RRC of the base station 200 is suspended, the UE 100 is in an RRC inactive state.

[0027] The NAS layer, which is located above the RRC layer in the UE 100, performs session management and mobility management for the UE 100. NAS signaling is transmitted between the NAS layer of the UE 100 and the NAS layer of the core network device 300.

[0028] The UE 100 has an application layer and the like in addition to the radio interface protocol.

[0029] (Radio Frame Configuration) In a 5G system, downlink transmission and uplink transmission are configured within a radio frame having a duration of 10 ms. For example, a radio frame is configured with 10 subframes. For example, one subframe may be 1 ms. Furthermore, one subframe may be configured with one or more slots. For example, the number of symbols that make up one slot is 14 for a normal CP (Cyclic Prefix) and 12 for an extended CP. Furthermore, the number of slots that make up one subframe varies depending on the set subcarrier spacing. For example, for a normal CP, if the subcarrier spacing is set to 15 kHz, the number of slots per subframe is 1 (i.e., 14 symbols); if the subcarrier spacing is set to 30 kHz, the number of slots per subframe is 2 (i.e., 28 symbols); if the subcarrier spacing is set to 60 kHz, the number of slots per subframe is 4 (i.e., 56 symbols); and if the subcarrier spacing is set to 120 kHz, the number of slots per subframe is 8 (i.e., 128 symbols). Furthermore, if the subcarrier spacing is set to 60 kHz for an extended CP, the number of slots per subframe is 4 (i.e., 48 symbols). That is, the number of slots constituting one subframe is determined based on the subcarrier spacing set by the base station 200. Furthermore, the number of symbols constituting one subframe is determined based on the subcarrier spacing set by the base station 200. That is, the number of symbols constituting a 1 ms subframe is determined based on the subcarrier spacing set by the base station 200, and the length of each symbol (length in the time direction) changes.

[0030] (Assumed Scenario) An assumed scenario in the mobile communication system 1 according to the embodiment will be described with reference to Fig. 3. Release 17 of 3GPP, a standardization project for mobile communication systems, specifies that when the UE 100 has flight path information, the UE 100 includes availability information (specifically, flightPathInfoAvailable) in an RRC message transmitted as a response to an RRC message from the base station 200.

[0031] 3 , in step S10, the base station 200 transmits, for example, an RRC connection re-establishment message to the UE 100. The UE 100 receives the RRC connection re-establishment message from the base station 200.

[0032] In step S20, after the re-establishment of the RRC connection is successfully completed, the UE 100 transmits an RRC connection re-establishment complete (RRCConnectionReestablishmentComplete) message to the base station 200 in response to the RRC connection re-establishment message. The base station 200 receives the RRC connection re-establishment complete message. If the UE 100 has available flight path information, the UE 100 can include the availability information in the RRC connection re-establishment complete message.

[0033] In step S30, the base station 200 transmits a UE information request (UEInformationRequest) message including a flight path information request (flightPathInfoReq) to the UE 100. The UE 100 receives the UE information request message from the base station 200.

[0034] In step S40, the UE 100 transmits a UE Information Response message including flight path information (flightPath) to the base station 200 based on the flight path information request. The base station 200 receives the UE Information Response message from the UE 100. In this manner, the base station 200 that has received the availability information can acquire the flight path information from the UE 100 by requesting the flight path information from the UE 100. This enables the network 10 to appropriately perform communication control (e.g., handover control, beamforming control, etc.) with the communication device based on the updated flight path information.

[0035] Recently, with regard to NR (New Radio), there has been discussion about the operation when route information is updated in the UE 100 after reporting the route information from the UE 100 to the base station 200. Currently, it is agreed that the network 10 can configure the UE 100 to trigger a route information update notification (flightpath update notification) based on a set distance difference (e.g., spatial difference) or a set time difference when a timestamp is set to be reported. The base station 200 that has received the update notification can obtain the updated route information from the UE 100 by requesting the route information from the UE 100.

[0036] In the current discussion, it is only mentioned that the condition for triggering notification of an update of route information is a set distance difference or time difference, and there is a concern that UE100 may not be able to notify the update of route information at the appropriate time.

[0037] For example, after notifying the UE 100 of an update of the route information due to a distance difference or a time difference, the UE 100 may lose the opportunity to notify the UE 100 of the update of the route information. For example, if the network 10 (base station 200) cannot successfully receive the notification of the update of the route information transmitted from the UE 100, for example, due to deterioration of the radio wave conditions, the network 10 (base station 200) cannot request the UE 100 to report the route information. In this case, since the UE 100 has already notified the update of the route information, there is a risk that the base station 200 will assume that the UE 100 has not requested the UE 100 to report the route information. As a result, the network 10 and the UE 100 may unintentionally enter a state where the route information cannot be updated, and there is a concern that the UE 100 may not be able to notify the update of the route information at an appropriate time. Furthermore, since the update of the route information is not specifically defined, there is a concern that the UE 100 may not be able to notify the update of the route information at an appropriate time. In one embodiment described below, an operation for enabling the notification of the update of the route information at an appropriate time will be described.

[0038] (Configuration of UE) The configuration of the UE 100 according to the embodiment will be described with reference to Fig. 4. The UE 100 includes a communication unit 110 and a control unit 120.

[0039] The communication unit 110 performs wireless communication with the base station 200 by transmitting and receiving radio signals to and from the base station 200. The communication unit 110 has at least one transmission unit 111 and at least one reception unit 112. The transmission unit 111 and the reception unit 112 may be configured to include multiple antennas and RF circuits. The antenna converts a signal into radio waves and radiates the radio waves into space. The antenna also receives radio waves in space and converts the radio waves into a signal. The RF circuit performs analog processing of the signal transmitted and received via the antenna. The RF circuit may include a high-frequency filter, an amplifier, a modulator, a low-pass filter, etc.

[0040] The control unit 120 performs various controls in the UE 100. The control unit 120 controls communication with the base station 200 via the communication unit 110. The operations of the UE 100 described above and below may be operations controlled by the control unit 120. The control unit 120 may include at least one processor capable of executing a program and a memory that stores the program. The processor may execute the program to perform the operations of the control unit 120. The control unit 120 may include a digital signal processor that performs digital processing of signals transmitted and received via the antenna and the RF circuit. The digital processing includes processing of a RAN protocol stack. The memory stores the program executed by the processor, parameters related to the program, and data related to the program. The memory may include at least one of read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), and flash memory. All or a portion of the memory may be contained within the processor.

[0041] The control unit 120 may include an RRC processing unit 121 and an RLC processing unit 122. The RRC processing unit 121 performs processing in the RRC layer. The RRC processing unit 121 may also be referred to as an RRC entity. The RLC processing unit 122 performs processing in the RLC layer, which is a layer lower than the RRC layer. The RLC processing unit 122 may also be referred to as an RLC entity. The RLC processing unit 122 may include, for example, a TM RLC entity that performs data transfer in a transparent mode (TM), a UM RLC entity that performs data transfer in an unacknowledged mode (UM), and an AM RLC entity that performs data transfer in an acknowledged mode (AM). The RRC processing unit 121 and the RLC processing unit 122 may be configured by one processor or by multiple processors.

[0042] In the UE 100 configured in this manner, the transmitter 111 transmits the route information to the base station 200, and then transmits a message to notify the base station of an update of the route information. The control unit 120 may execute retransmission control to retransmit the message if a predetermined period has elapsed since the message was transmitted to the base station and an acknowledgment based on the message has not been received from the base station. Furthermore, the receiver 212 of the base station 200 receives a message from the UE 100 notifying the base station 200 of an update of the route information after receiving the route information from the UE 100. The receiver 212 receives the message by having the UE 100 execute retransmission control to retransmit the message if the UE 100 has not received a acknowledgment based on the message from the base station 200 even after a predetermined period has elapsed since the message was transmitted to the base station 200. This allows the UE 100 to retransmit the message if there is a possibility that the base station 200 has not successfully received the message notifying the base station of an update of the route information. As a result, it is possible to avoid a situation in which the network 10 and the UE 100 are unintentionally unable to update the route information. The UE 100 can notify the update of the route information at an appropriate timing even after notifying the update of the route information.

[0043] Furthermore, in the UE 100, the control unit 120 can report a timestamp when timestamp reporting is set. Therefore, when timestamp reporting based on route information is set, the control unit 120 determines whether to notify the base station 200 of an update to the route information based on the time difference set from the base station 200. Furthermore, the control unit 120 performs a determination based on the distance difference before a determination based on the time difference. Therefore, even when timestamp reporting is set, the control unit 120 determines whether to notify the base station 200 of an update to the route information based on the distance difference set from the base station 200. This allows the UE 100 to flexibly determine whether to notify the base station 200 of an update to the route information when timestamp reporting is set, compared to when only a determination based on the time difference is possible. As a result, the UE 100 can notify the base station 200 of an update to the route information at an appropriate timing. Furthermore, since the conditions for notifying the base station 200 of an update to the route information are clarified, the network 10 and the UE 100 can properly cooperate to update the route information.

[0044] (Configuration of Base Station) The configuration of the base station 200 according to this embodiment will be described with reference to Fig. 5. The base station 200 includes a communication unit 210, a network communication unit 220, and a control unit 230.

[0045] The communication unit 210 receives, for example, a radio signal from the UE 100 and transmits the radio signal to the UE 100. The communication unit 210 has at least one transmission unit 211 and at least one reception unit 212. The transmission unit 211 and the reception unit 212 may be configured to include an RF circuit. The RF circuit performs analog processing of signals transmitted and received via an antenna. The RF circuit may include a high-frequency filter, an amplifier, a modulator, a low-pass filter, etc.

[0046] The network communication unit 220 transmits and receives signals to and from the network. For example, the network communication unit 220 receives signals from adjacent base stations connected via an Xn interface, which is an interface between base stations, and transmits the signals to the adjacent base stations. The network communication unit 220 also receives signals from the core network device 300 connected via an NG interface, and transmits the signals to the core network device 300.

[0047] The control unit 230 performs various controls in the base station 200. The control unit 230 controls, for example, communication with the UE 100 via the communication unit 210. The control unit 230 also controls, for example, communication with a node (e.g., a neighboring base station, the core network device 300) via the network communication unit 220. The operations of the base station 200 described above and below may be controlled by the control unit 230. The control unit 230 may include at least one processor capable of executing a program and a memory that stores the program. The processor may execute the program to perform the operations of the control unit 230. The control unit 230 may include a digital signal processor that performs digital processing of signals transmitted and received via the antenna and the RF circuit. The digital processing includes processing of a RAN protocol stack. The memory stores programs executed by the processor, parameters related to the programs, and data related to the programs. All or a part of the memory may be included in the processor.

[0048] In the base station 200 configured as described above, the receiver 212 receives a message from the UE 100 notifying the base station 200 of an update of the route information after receiving the route information from the UE 100. The receiver 212 receives the message by the UE 100 performing retransmission control to retransmit the message if the UE 100 has not received an acknowledgment based on the message from the base station 200 even after a predetermined period has elapsed since transmitting the message to the base station 200. This allows the UE 100 to retransmit the message if there is a possibility that the base station 200 has not normally received the message notifying the update of the route information. As a result, it is possible to avoid a situation in which the network 10 and the UE 100 are unable to update the route information unintentionally. The UE 100 can notify the update of the route information at an appropriate timing even after notifying the update of the route information.

[0049] 6 to 8, an example of operation of the mobile communication system 1 will be described. Note that, in the following, the operation of the base station 200 may be the operation of the network 10.

[0050] Step S101: As shown in FIG. 6 , the transmission unit 211 of the base station 200 transmits, for example, a message including configuration information to the UE 100. The transmission unit 211 may transmit, for example, an RRC reconfiguration message to the UE 100 as the message including the configuration information. Note that the message may be at least one of an RRC setup message, an RRC reestablishment message, and an RRC resume message. Note that the message transmitted in S101 may be, for example, a message for causing the UE 100 to transmit a message including availability information, which will be described later.

[0051] The receiver 112 of the UE 100 receives a message from the base station 200. The receiver 112 may receive, for example, at least one of an RRC reconfiguration message, an RRC setup message, an RRC re-establishment message, and an RRC resume message.

[0052] The setting information may include, for example, predetermined setting information related to update control for notifying the base station 200 of an update of the route information. The predetermined setting information may include, for example, a threshold for determining whether to notify the base station 200 of an update of the route information. The threshold may be information that triggers the notification of the update of the route information. The threshold may be information for setting a distance difference (for example, a spatial difference) and / or a time difference in the UE 100. The threshold may include a distance threshold for setting the distance difference in the UE 100 and a time threshold for setting the time difference in the UE 100.

[0053] The distance threshold may be used, for example, for comparison with a calculated distance difference calculated based on a new route of the UE 100. The new route may be a route different from the reported route. The new route is a route that is at least partially changed from the reported route. The new route may be a route newly acquired by the UE 100 (controller 120) after reporting the route information. The distance threshold may be used for comparison with a distance difference based on a point on the changed route. The distance threshold may be used, for example, for comparison with a distance difference based on a point on the changed route. The distance threshold may be used, for example, for comparison with (a) a distance from a point on the reported route to a point on the changed route, (b) a distance from a destination of the reported route to a destination of the changed route, or (c) a distance from a measured position of the UE 100 (e.g., a latest measured position (current position)) to a point on the route reported by the UE 100 that is closest to the measured position. In addition, the distance threshold may be used, for example, to compare the distance from the position of UE100 to a specified point on the route when the time measured by UE100 reaches a specified time (e.g., the time of the timestamp) at the specified point.

[0054] The time threshold may be used, for example, for comparison with a calculated time difference calculated based on a scheduled time of a new route of the UE 100. Furthermore, the time threshold may be used, for example, for comparison with a calculated time difference calculated based on a measurement time of the UE 100. The time threshold may be used, for example, for comparison with a time difference between an estimated time of arrival at a point on a route reported by the UE 100 and the time at which the UE 100 arrives at the point. The time threshold may be used, for example, for comparison with (a) a time difference between an estimated time of arrival at each point on the reported route (i.e., the time of the reported timestamp) and an estimated time of arrival at each point on the changed route, (b) a time difference between an estimated time of arrival at a destination on the reported route and an estimated time of arrival at the destination on the changed route, or (c) a time difference between an estimated time of arrival at a point on the route reported by the UE 100 (i.e., the time of the reported timestamp) and the time at which the UE 100 arrives at the point. 7, the setting information (e.g., OtherConfig) may include route setting information (e.g., UAV-FlightPathAssistanceConfig) related to the setting of route information. The route setting information may include predetermined setting information or may be predetermined setting information.

[0055] The configuration information may also include a timer value (hereinafter referred to as a retransmission timer value) indicating a predetermined period (hereinafter referred to as a period t) described below. As shown in E12 of FIG. 7, the path configuration information may include a retransmission timer value (uav-flightPathRetransmissionTimer). This allows the receiving unit 112 of the UE 100 to receive the retransmission timer value from the base station 200. The control unit 120 of the base station 200 may include the retransmission timer value in the configuration information when allowing the UE 100 to notify the base station 200 of an update of the path information using a message (for example, a UE assistance information message) that can be transmitted at any timing.

[0056] The setting information (or predetermined setting information) may include information (hereinafter appropriately referred to as determination trigger information) that triggers a determination of whether or not to notify an update of route information. The determination trigger information may be, for example, information that identifies an event for calculating a distance difference and / or a time difference. The control unit 120 may start the determination based on the occurrence of the event. The event may occur, for example, by acquiring (current) location information (or location coordinates) of the UE 100. The event may occur at a specific time, for example, a scheduled arrival time at each point on a planned route. Furthermore, the determination trigger information may include information that identifies a determination period, a determination frequency, and / or a determination interval.

[0057] The control unit 120 of the UE 100 may, for example, execute the control of the following processing when route information is available to the UE 100.

[0058] Step S102: The transmitter 111 of the UE 100 transmits a message including availability information to the base station 200. The receiver 212 of the base station 200 receives the message including the availability information from the UE 100. The message is, for example, an RRC Reestablishment Complete message. The message used to transmit the availability information may be, in addition to the RRC re-establishment complete message, at least one of an RRC setup complete message, an RRC connection re-establishment complete message, an RRC reconfiguration complete message, an RRCReconfigurationComplete message, an RRC resume complete message, and a UE assistance information message.

[0059] When the control unit 230 of the base station 200 receives the availability information, the control unit 230 may perform control to execute the process of step S103.

[0060] Step S103: The transmitter 211 of the base station 200 transmits a UE information request (UEInformationRequest) message including configuration information for requesting a report of route information to the UE 100. The receiver 112 of the UE 100 receives the UE information request message including the configuration information from the base station 200. The message may be route information and / or a message requesting a report of route information. The UE information request message is a message used by the network 10 to retrieve information from the UE 100.

[0061] The setting information may be information (for example, FlightPathInfoReportConfig) for specifying a setting for reporting route information. Note that the setting information may include, for example, information (for example, maxWayPointNumber) indicating the maximum number of points on a route (for example, waypoints) that can be included in a report of route information when the UE 100 can use route information. The setting information may include information (for example, includeTimeStamp) indicating whether a timestamp of each point can be reported in a report of route information when the UE 100 can use timestamp information. With this information, the UE 100 may be configured to report a timestamp. The setting information may include information requesting (instructing) a report of a timestamp. The control unit 120 of the UE 100 may perform control to execute the process of step S104 based on the setting information.

[0062] The setting information for requesting a route information report may include the above-mentioned predetermined setting information related to update control for notifying the base station 200 of an update of the route information. The setting information or the predetermined setting information may include a retransmission timer value. Furthermore, the setting information or the predetermined setting information may include determination trigger information.

[0063] Step S104: The transmitter 111 of the UE 100 transmits a UE information response message including route information related to the route schedule of the UE 100 to the base station 200. As a result, the transmitter 111 transmits the route information to the UE 100. The receiver 212 of the base station 200 receives the UE information response message including the route information from the UE 100. Note that the UE information response message is a message used to transfer information requested by the network 10.

[0064] The route information may include, for example, information regarding a planned route of the UE 100. The route information may indicate, for example, a planned flight route as the planned route of the UE 100. The route information may be referred to as, for example, a "flightPathInfoReport" or "flightPath". Furthermore, the route information may indicate a planned travel route when the UE 100 travels on a land route, or may indicate a planned route when the UE 100 sails on a sea route.

[0065] The route information may include location information including location coordinates (e.g., location coordinates) of the UE 100. The location coordinates may represent planned locations. The location information may be waypoint location information (e.g., wayPointLocation) including UE location coordinates for aerial UE operations. The waypoint location information may be an information element (LocationInfo) used to transfer detailed location information available to the UE 100 to correlate measurements with UE position information. The location information may consist of (a list of) multiple waypoint location information. The waypoints may represent planned locations for the UE.

[0066] The position coordinates may correspond to each point on the route. Thus, a planned route may be composed of multiple position coordinates. The route information may include information indicating the position coordinates of a destination. The information indicating the position coordinates of a destination may be position coordinates mapped to a specific position (e.g., the first or last of (a list of) multiple waypoint position information). Furthermore, the information indicating the position coordinates of a destination may be associated with the information indicating the destination.

[0067] The route information may also include timestamp information (e.g., timeStamp). The timestamp information may include information indicating a timestamp of a waypoint representing a planned location of the UE. The information may be, for example, information indicating absolute time in "YY-MM-DD HH:MM:SS" format using BCD (Binary-Coded Decimal) encoding (e.g., AbsoluteTimeInfo).

[0068] The control unit 120 of the UE 100 may acquire route information from, for example, an air traffic control system. The control unit 120 may acquire (generate) route information by receiving a Global Navigation Satellite System (GNSS) signal and / or a Global Positioning System (GPS) signal for detecting a position, a speed, an altitude, etc. The control unit 120 may detect a position, a speed, an altitude, etc. using a sensor provided in the UE 100 and acquire (generate) route information.

[0069] The route information may include information indicating the altitude and / or the speed of the UE 100. The UE 100 may include a sensor for detecting the altitude and / or the speed of the UE 100.

[0070] Note that the control unit 120 of the UE 100 may acquire route information regarding a schedule of a new route after reporting the route information. For example, the control unit 120 may acquire the route information regarding a schedule of a new route based on a user input, a movement status of the UE 100, or the like.

[0071] Step S105: The control unit 120 of the UE 100 determines whether to notify the update of the route information. The control unit 120 may start the determination based on the setting information. The control unit 120 may start the determination based on, for example, the determination trigger information. Details of the determination will be described later.

[0072] When the control unit 120 determines that the route information update should be notified, the control unit 120 may execute the process of step S111 in Fig. 8. Therefore, the control unit 120 may execute update control for notifying the route information update. When the control unit 120 determines that the route information update should not be notified, the control unit 120 may perform control such that the process of step S111 in Fig. 8 is not executed.

[0073] Step S111: As shown in Fig. 8 , the transmitter 111 of the UE 100 transmits availability information to the base station 200. The transmitter 111 transmits, for example, a UE assistance information message including the availability information to the base station 200. Therefore, the controller 120 of the UE 100 may include the availability information in the UE assistance information message. The controller 120 of the UE 100 can perform control so as to transmit the availability information to the base station 200.

[0074] The RRC processing unit 121 of the control unit 120 may generate an RRC message as a message for notifying the base station 200 of an update of the route information. The RRC processing unit 121 may include availability information in the RRC message. The RRC processing unit 121 may control the transmission unit 111 to transmit the RRC message. As a result, the transmission unit 111 transmits an RRC message in the RRC layer to notify the base station 200 of the update of the route information. After transmitting the route information to the base station 200, the transmission unit 111 can transmit the RRC message as a message for notifying the base station of the update of the route information.

[0075] The RRC message may be, for example, a message that can be transmitted at any timing by the UE 100. The message may be a message transmitted from the UE 100 as a source, such as a UE assistance information message used for indicating UE assistance information to the network. Alternatively, the RRC message may be a message (e.g., an RRC reconfiguration complete message, an RRC setup complete message, an RRC reestablishment complete message, or an RRC resume complete message) transmitted as a response to an RRC message (e.g., an RRC reconfiguration message, an RRC setup message, an RRC reestablishment message, or an RRC resume message) from the base station 200.

[0076] When the base station 200 permits the transmission unit 111 to notify the UE 100 of an update of the route information using a message that can be transmitted at any timing of the UE 100 (hereinafter, a UE-originated message), the transmission unit 111 may transmit the UE-originated message as a message notifying the UE 100 of an update of the route information. On the other hand, when the base station 200 does not permit the transmission unit 111 to notify the UE 100 of an update of the route information using a UE-originated message, the transmission unit 111 may cancel the transmission of the message notifying the UE 100 of an update of the route information. Alternatively, the transmission unit 111 may transmit a message that is transmitted as a response to an RRC message from the base station 200 as a message notifying the UE 100 of an update of the route information.

[0077] For example, if the configuration information includes a retransmission timer value, the control unit 120 may determine that the UE-originated message is permitted to be used to notify the updated route information. Therefore, if the control unit 120 receives a retransmission timer value, the control unit 120 may consider that the UE-originated message is permitted to be transmitted as a message notifying the updated route information. On the other hand, if the configuration information does not include a retransmission timer value, the control unit 120 may determine that the UE-originated message is not permitted to be used to notify the updated route information.

[0078] The availability information transmitted after reporting the route information may be treated as a notification of an update of the route information. The availability information may be information indicating that new route information is available or that updated route information is available. In this case, the availability information in step S111 may indicate that updated route information is available. The availability information in step S102 may indicate that new route information is available.

[0079] The RRC processing unit 121 may trigger, request, configure, or indicate to a lower layer to transmit a message notifying of an update of route information, for example, in an RLC packet (e.g., an AM Data (AMD) Protocol Data Unit (PDU)) including a field for requesting an acknowledgment or negative acknowledgment. As a result, the RLC processing unit 122 may generate an RLC packet including, as a field for requesting an acknowledgment or negative acknowledgment, for example, a P field indicating whether the transmitting side of the AM RLC entity requests a status (STATUS) report from the peer AM RLC entity. The RLC processing unit 122 may set a value indicating a request for a status report in this field.

[0080] The RLC processing unit 122 may also generate two identical copies of an RLC packet corresponding to a message notifying an update of route information, and may send one RLC packet to a lower layer for message transmission and the other RLC packet to a retransmission buffer.

[0081] In this operation example, it is assumed that the receiver 212 of the base station 200 has not received the availability information (or a message including the availability information) from the UE 100. When the receiver 212 of the base station 200 has received the availability information from the UE 100, the receiver 212 may execute the processes from step S114 onwards.

[0082] In the following description, the control unit 120 that performs processing in the RRC layer will be referred to as an RRC processing unit 121. The control unit 120 that performs processing in the RLC layer will be referred to as an RLC processing unit 122.

[0083] Step S112: The RRC processing unit 121 starts a timer (hereinafter, appropriately referred to as a retransmission timer) based on transmission of a message notifying the base station 200 of an update of the route information. The RRC processing unit 121 may start the retransmission timer based on transmission of a message including availability information (after transmitting the reported route information).

[0084] Furthermore, the RRC processing unit 121 starts a retransmission timer to which the retransmission timer value has been set. When the RRC processing unit 121 has received the retransmission timer value from the base station 200, the RRC processing unit 121 may set the retransmission timer to the retransmission timer value. When the retransmission timer value is specified in advance in the specifications, the RRC processing unit 121 may set the specified value as the retransmission timer value in the retransmission timer.

[0085] Step S113: The retransmission timer expires after the period t has elapsed. If the period t has elapsed since the message of step S112 was transmitted and an acknowledgment based on the message has not been received from the base station 200, the RRC processing unit 121 can execute retransmission control. The expiration of the retransmission timer allows the control unit 120 to determine that the period t has elapsed since the message was transmitted. The control unit 120 may determine that the base station 200 has not successfully received the message after the period t has elapsed. The control unit 120 may execute retransmission control when it determines that the base station 200 has not successfully received the message. Therefore, the RRC processing unit 121 may execute retransmission control based on the expiration of the retransmission timer. Specifically, the RRC processing unit 121 can execute the following processes.

[0086] Step S114: The RRC processing unit 121 executes retransmission control to retransmit a message notifying update of the route information. Specifically, the RRC processing unit 121 controls the transmitter 111 to retransmit a UE assistance information message including availability information. As a result, the transmitter 111 retransmits the UE assistance information message to the base station 200.

[0087] In this operation example, the receiving unit 212 of the base station 200 receives a message including availability information from the UE 100. Based on the received message, the control unit 230 of the base station 200 performs control to execute the process of step S116.

[0088] Step S115: The RRC processing unit 121 starts the retransmission timer in the same manner as in step S112.

[0089] Step S116: Based on the reception of the message, the transmission unit 211 of the base station 200 transmits an acknowledgment to the UE 100. In this operation example, the transmission unit 211 transmits an acknowledgment (specifically, an RLC ACK (Acknowledgement)) to the UE 100 in the RLC layer.

[0090] The RLC processing unit of the control unit 230 may, for example, generate a packet for acknowledgment. The packet may be, for example, a packet (e.g., a STATUS PDU) including an acknowledgment SN (ACK_SN) field. The acknowledgment field may indicate the sequence number (SN) of the next unreceived RLC SDU (Service Data Unit) that is not reported as missing in the packet (STATUS PDU). The RLC processing unit may also include in the packet a field (NACK_SN) indicating the sequence number of the RLC SDU (or RLC SDU segment) detected as lost by the receiving side of the AM RLC entity.

[0091] The receiver 112 of the UE 100 receives the acknowledgment from the base station 200. In this operation example, the receiver 112 receives the acknowledgment from the base station 200 in the RLC layer, i.e., in a layer lower than the RRC layer. The RLC processor 122 of the controller 230 may execute the process of step S117 based on the reception of the acknowledgment.

[0092] For example, when the RLC processing unit 122 receives a packet including an ACK_SN field, it may interpret this as meaning that all RLC SDUs up to the RLC SDU with the sequence number in the ACK_SN field, excluding the RLC SDU with the sequence number indicated by the NACK_SN, have been received by the peer AM RLC entity (i.e., base station 200). If the RLC processing unit 122 interprets this as meaning that the RLC SDU with the sequence number of the packet corresponding to the message notifying the update of route information has been received by the base station 200, it may perform the process of step S117. Furthermore, the RLC processing unit 122 may discard the RLC packet in the retransmission buffer based on this interpretation.

[0093] Note that, when a negative acknowledgement is received or when there is no response from the base station 200 for a certain period shorter than the period t, the RLC processing unit 122 may execute control to retransmit the RLC packets in the retransmission buffer. The RRC processing unit of the base station 200 and the RLC processing unit 122 of the UE 100 may execute, for example, an Automatic Repeat request (ARQ) procedure.

[0094] Step S117: The RLC processing unit 122 indicates to the upper layer that it has received an acknowledgment to the message notifying the update of the route information (hereinafter referred to as an ACK acknowledgment). The RLC processing unit 122 may provide the upper layer with information indicating that the acknowledgment has been received, for example, as an ACK acknowledgment. The RLC processing unit 122 may provide the upper layer with an acknowledgment to the message notifying the update of the route information, for example, as an ACK acknowledgment. As a result, the RRC processing unit 121 receives the ACK acknowledgment from the lower layer. The RRC processing unit 121 may receive the ACK acknowledgment from the RLC processing unit 122, for example, via a PDCP processing unit (PDCP entity) included in the control unit 120. As a result, the RRC processing unit 121 can recognize that the message notifying the update of the route information has been received by the base station 200.

[0095] Step S118: The RRC processing unit 121 stops the retransmission timer upon receiving an acknowledgment based on the message notifying of the update of the route information from the base station 200. As a result, the retransmission timer does not expire, and therefore, when the RRC processing unit 121 (i.e., the control unit 120) receives an acknowledgment from the base station 200, it can stop retransmission control even if it does not receive a request for reporting route information (e.g., a message including information for specifying the setting for reporting route information) from the base station 200 after transmitting the message.

[0096] Thereafter, the base station 200 may or may not execute the process of step S103 based on the availability information. The control unit 120 of the UE 100 may control so as not to execute retransmission control even if the process of step S103 is not executed.

[0097] As described above, the transmitter 111 of the UE 100 transmits the route information to the base station 200, and then transmits a message notifying the base station of an update of the route information. If a predetermined period has elapsed since the message was transmitted to the base station and an acknowledgment based on the message has not been received from the base station, the control unit 120 may execute retransmission control to retransmit the message. Furthermore, the receiver 212 of the base station 200 receives a message from the UE 100 notifying the base station 200 of an update of the route information after receiving the route information from the UE 100. The receiver 212 receives the message by having the UE 100 execute retransmission control to retransmit the message if the UE 100 has not received an acknowledgment based on the message from the base station 200 even after a predetermined period has elapsed since the message was transmitted to the base station 200. This allows the UE 100 to retransmit the message if there is a possibility that the base station 200 has not successfully received the message notifying the base station of an update of the route information. As a result, it is possible to avoid a situation in which the network 10 and the UE 100 are unintentionally unable to update the route information. The UE 100 can notify the update of the route information at an appropriate timing even after notifying the update of the route information.

[0098] The transmitter 111 may transmit an RRC message as a message to notify the update of the route information in the RRC layer. The receiver 112 may receive an acknowledgement from the base station 200 in a layer lower than the RRC layer. Thus, even if a response message to the message notifying the update of the route information is not defined in the RRC layer, the UE 100 can recognize that the base station 200 has received the RRC message based on the reception of the acknowledgement.

[0099] Furthermore, when the control unit 120 receives an acknowledgment, it may stop retransmission control even if it does not receive a request for reporting route information from the base station 200 after transmitting the message.

[0100] Furthermore, the receiving unit 112 may receive a retransmission timer value indicating a predetermined period from the base station 200. The control unit 120 may start a retransmission timer set with the retransmission timer value based on the transmission of a message. Retransmission control may be performed based on the expiration of the retransmission timer value. This allows the network 10 to control the retransmission timer value and therefore control the retransmission of messages.

[0101] Furthermore, when the control unit 120 receives the retransmission timer value, the control unit 120 may consider that the UE 100 is permitted to transmit a message that can be transmitted at any timing as a message. As a result, the base station 200 can notify the UE 100 that the base station permits the UE 100 to notify the UE 100 of update of route information using a UE-originated message by transmitting the retransmission timer value. The network 10 can omit transmitting other information indicating the permission, thereby saving radio resources.

[0102] (First Operation Example Regarding Determination of Update Notification) Next, a first operation example regarding determination of update notification will be described with reference to FIG. 9 . Descriptions of parts similar to the above-described operation example will be omitted. The control unit 120 of the UE 100 may execute this operation example, for example, in the above-described step S105. The control unit 120 may start the following process, for example, based on setting information (for example, determination trigger information). Note that the receiving unit 112 of the UE 100 may have received at least one of a distance threshold for setting a distance difference and a time threshold for setting a time difference from the base station 200. The control unit 120 of the UE 100 may have acquired route information regarding a new route.

[0103] Step S201: The control unit 120 calculates a distance difference. The control unit 120 may calculate the distance difference based on, for example, a new route of the UE 100. The control unit 120 may calculate, as the distance difference, a difference between a predetermined point on the new route (for example, a point closest to the current location of the UE 100) and at least one or more points on the reported route. The control unit 120 may also calculate, as the distance difference, a difference between each point on the new route and each point on the reported route. The control unit 120 may also calculate, as the distance difference, a difference between the destination of the new route and the reported route.

[0104] The control unit 120 may calculate a difference in distance between the position of the UE 100 and a point on the route. The control unit 120 may calculate a distance from the position of the UE 100 when the time measured by the UE 100 reaches a predetermined time (e.g., the time of a timestamp) at a predetermined point on the route to the predetermined point. Furthermore, the control unit 120 may calculate, for example, a distance from the measured position of the UE 100 (e.g., the current position) to a point on the route reported by the UE 100 that is closest to the measured position.

[0105] The control unit 120 may calculate the distance difference in two dimensions or may calculate the distance difference in three dimensions, i.e., the spatial difference, as the distance difference. Note that if the control unit 120 has calculated the distance difference before determining whether to issue an update notification, the control unit 120 may omit this step.

[0106] Step S202: The control unit 120 determines whether the calculated distance difference exceeds the distance threshold. If the calculated distance difference exceeds the distance threshold, the control unit 120 executes the process of step S206. On the other hand, if the calculated distance difference does not exceed the distance threshold, the control unit 120 executes the process of step S203. Note that the distance threshold may be configured by a single parameter (e.g., a predetermined threshold) or may be configured by multiple parameters (e.g., a predetermined threshold, an offset value, etc.). If the control unit 120 has calculated multiple calculated distance differences, the control unit 120 may execute the process of step S206 if at least a certain number (or all) of the multiple calculated distance differences exceed the distance threshold. On the other hand, the control unit 120 may execute the process of step S203 if at least a certain number (or all) of the multiple calculated distance differences do not exceed the distance threshold.

[0107] Note that, when the calculated distance difference based on the position of UE 100 exceeds the distance threshold, control unit 120 may acquire route information indicating a new route.

[0108] Step S203: The control unit 120 determines whether a timestamp has been reported. For example, the control unit 120 may determine that a timestamp has been reported if a timestamp is present in the route information reported to the base station 200 (i.e., a timestamp is included). On the other hand, for example, the control unit 120 may determine that a timestamp has not been reported if a timestamp is not present in the route information reported to the base station 200 (i.e., a timestamp is not included).

[0109] If the control unit 120 determines that the timestamp has been reported, the control unit 120 executes the process of step S204. On the other hand, if the control unit 120 determines that the timestamp has not been reported, the control unit 120 may terminate the process. In this case, the UE 100 does not need to execute the process of step S111.

[0110] Alternatively, the control unit 120 may determine, for example, at least one of (a) whether or not a timestamp report has been set, (b) whether or not a timestamp report has been requested (instructed), and (c) whether or not an instruction has been given to assign a timestamp to each waypoint. The control unit 120 may execute the process of step S204, for example, when (a) a timestamp report has been set, (b) a timestamp report has been requested (instructed), or (c) an instruction has been given to assign a timestamp to each waypoint. If not, the control unit 120 may end the process.

[0111] Step S204: The control unit 120 calculates the time difference. The control unit 120 may calculate the time difference based on, for example, the scheduled time of the new route of the UE 100. The control unit 120 may calculate the time difference based on, for example, the scheduled time of arrival at a point on the changed route and a set time difference (for example, a time threshold). The control unit 120 may calculate the time difference based on, for example, the scheduled time of arrival at the destination of the reported route and the scheduled time of arrival at the destination of the changed route. The control unit 120 may calculate the time difference based on, for example, the arrival time at a point on the route and a timestamp at the point.

[0112] If the control unit 120 calculates the time difference before determining whether to issue an update notification, the control unit 120 may omit this step.

[0113] Step S205: The control unit 120 determines whether the calculated time difference exceeds the time threshold. If the calculated time difference exceeds the time threshold, the control unit 120 executes the process of step S206. On the other hand, if the calculated time difference does not exceed the time threshold, the control unit 120 ends the process. Note that the time threshold may be configured by a single parameter (e.g., a predetermined threshold) or may be configured by multiple parameters (e.g., a predetermined threshold, an offset value, etc.).

[0114] Step S206: The control unit 120 determines to notify the update of the route information. The control unit 120 may execute the process of step S111, for example.

[0115] In step S202, the control unit 120 determines whether to notify the base station 200 of an update to the route information based on the distance difference set by the base station 200. In step S205, the control unit 120 determines whether to notify the base station 200 of an update to the route information based on the time difference set by the base station 200.

[0116] As described above, the control unit 120 can report a timestamp when timestamp reporting is set. Therefore, when timestamp reporting based on route information is set, the control unit 120 determines whether to notify the base station 200 of an update to the route information based on the time difference set from the base station 200. Furthermore, the control unit 120 performs a determination based on the distance difference before a determination based on the time difference. Therefore, even when timestamp reporting is set, the control unit 120 determines whether to notify the base station 200 of an update to the route information based on the distance difference set from the base station 200. This allows the UE 100 to flexibly determine whether to notify the base station 200 of an update to the route information when timestamp reporting is set, compared to when only a determination based on the time difference is possible. As a result, the UE 100 can notify the base station 200 of an update to the route information at an appropriate timing. Furthermore, since the conditions for notifying the base station 200 of an update to the route information are clarified, the network 10 and the UE 100 can properly cooperate to update the route information.

[0117] Furthermore, the receiving unit 112 may receive at least one of a distance threshold for setting a distance difference and a time threshold for setting a time difference from the base station. As shown in steps S202, S205, and S206, the control unit 120 may determine to notify the update of the route information when the calculated distance difference calculated based on the new route of the UE 100 exceeds the distance threshold, or when the calculated time difference calculated based on the scheduled time of the new route of the UE 100 exceeds the time threshold. As a result, for example, when timestamp reporting is set, the UE 100 can notify the update of the route information when the calculated distance difference exceeds the distance threshold, even if the calculated time difference does not exceed the time threshold. Since there are more opportunities to notify the update of the route information, communication control can be performed based on appropriate route information.

[0118] Furthermore, as shown in steps S202 and S206, when the calculated distance difference exceeds the distance threshold, the control unit 120 may determine to notify the base station 200 of an update of the route information without making a determination based on the time difference set by the base station 200. Therefore, the control unit 120 may prioritize a determination based on the distance difference over a determination based on the time difference, regardless of whether a timestamp report is set or not. This allows the UE 100 to omit the process of determining based on the time difference, thereby reducing the number of determination processes. As a result, the power consumption of the UE 100 can be suppressed.

[0119] (Second Operation Example Regarding Determination of Update Notification) Next, a second operation example regarding determination of update notification will be described with reference to Fig. 10. Description of parts similar to the above-described operation example will be omitted.

[0120] Step S301: The control unit 120 executes the same process as step S203. The control unit 120 may execute the process of step S302, for example, when (a) timestamp reporting is set, (b) timestamp reporting is requested (instructed), (c) timestamp assignment to each waypoint is instructed, or (d) a timestamp is present in the route information reported to the base station 200 (i.e., a timestamp is included). If this is not the case, the control unit 120 may execute the process of step S304.

[0121] Step S302: The control unit 120 calculates the time difference. The control unit 120 may execute the same process as in step S204.

[0122] Step S303: The control unit 120 executes the same process as step S205. If the calculated time difference exceeds the time threshold, the control unit 120 executes the process of step S306. On the other hand, if the calculated time difference does not exceed the time threshold, the control unit 120 executes the process of step S304.

[0123] Step S304: The control unit 120 calculates the distance difference. The control unit 120 may execute the same process as in step S201.

[0124] Step S305: The control unit 120 executes the same process as step S202. If the calculated distance difference exceeds the distance threshold, the control unit 120 executes the process of step S206. On the other hand, if the calculated distance difference does not exceed the distance threshold, the control unit 120 ends the process.

[0125] Step S306: The control unit 120 determines to notify the update of the route information. The control unit 120 may execute the same process as in step S206.

[0126] As described above, as shown in steps S303 and S306, when the calculated time difference exceeds the time threshold, the control unit 120 may determine to notify the base station 200 of an update of the route information without making a determination based on the distance difference set by the base station 200. That is, the control unit 120 may prioritize a determination based on the time difference over a determination based on the distance difference. This allows the UE 100 to omit the process of determining based on the distance difference, thereby reducing the number of determination processes. As a result, the power consumption of the UE 100 can be suppressed.

[0127] (Third Operation Example Regarding Determination of Update Notification) Next, a second operation example regarding determination of update notification will be described with reference to Fig. 11. Description of the same parts as in the above operation example will be omitted.

[0128] Step S401: The control unit 120 calculates the distance difference. The control unit 120 may execute the same process as in step S201.

[0129] Step S402: The control unit 120 executes the same process as step S202. If the calculated distance difference exceeds the distance threshold, the control unit 120 executes the process of step S403. On the other hand, if the calculated distance difference does not exceed the distance threshold, the control unit 120 ends the process.

[0130] Step S403: The control unit 120 executes the same process as step S203. The control unit 120 may execute the process of step S404, for example, when (a) timestamp reporting is set, (b) timestamp reporting is requested (instructed), (c) timestamp assignment to each waypoint is instructed, or (d) a timestamp is present in the route information reported to the base station 200 (i.e., a timestamp is included). If this is not the case, the control unit 120 may execute the process of step S406.

[0131] Step S404: The control unit 120 calculates the time difference. The control unit 120 may execute the same process as in step S204.

[0132] Step S405: The control unit 120 executes the same process as step S205. If the calculated time difference exceeds the time threshold, the control unit 120 executes the process of step S406. On the other hand, if the calculated time difference does not exceed the time threshold, the control unit 120 ends the process.

[0133] Step S406: The control unit 120 determines to notify the update of the route information. The control unit 120 may execute the same process as in step S206.

[0134] As described above, the receiving unit 112 may receive from the base station a distance threshold for setting a distance difference and a time threshold for setting a time difference. As shown in steps S402, S405, and S406, the control unit 120 may determine to notify the update of the route information when the calculated distance difference calculated based on the new route of the UE 100 exceeds the distance threshold and when the calculated time difference calculated based on the scheduled time of the new route of the UE 100 exceeds the time threshold. This allows the UE 100 to determine whether to notify the update of the route information based on both the determination based on the time difference and the determination based on the distance difference, thereby avoiding frequent notification of the update of the route information. As a result, it is possible to suppress the consumption of a large amount of radio resources based on the notification of the update of the route information.

[0135] Furthermore, if the calculated distance difference does not exceed the distance threshold, the control unit 120 may determine not to notify the update of the route information without making a determination based on the time difference set by the base station 200. This allows the UE 100 to omit the process of determination based on the time difference, thereby reducing the number of determination processes. As a result, the power consumption of the UE 100 can be suppressed.

[0136] Furthermore, as shown in steps S403 and S406, when a timestamp report has not been made, the control unit 120 may make a determination based on the distance difference set by the base station 200, without making a determination based on the time difference set by the base station 200. That is, the control unit 120 may determine to notify the update of the route information only based on the determination based on the time difference. This allows the UE 100 to notify the update of the route information even when the timestamp report has not been set.

[0137] Since the UE 100 executes the process of step S404 after the process of step S403, if the timestamp report is not set, the processes of steps S404 and S405 can be omitted. This reduces the number of processes of the UE 100, and suppresses power consumption of the UE 100.

[0138] (Other Embodiments) In the above-described embodiment, the case where the UE 100 receives the reception response from the base station 200 at the RLC layer has been described as an example, but the present invention is not limited to this. The UE 100 may receive the reception response from the base station 200 at the MAC layer, for example. The UE 100 may stop retransmission control based on the reception response at the MAC layer.

[0139] In the above-described embodiment, the UE 100 may have received from the base station 200 the timer value of a prohibition timer related to transmission of availability information. The control unit 120 may set the prohibition timer to the timer value. The control unit 120 of the UE 100 may start the prohibition timer (to which the timer value is set) based on transmission of a message including availability information. If the prohibition timer is running, the control unit 120 may prohibit transmission of a message including availability information. If the prohibition timer has expired or is stopped, the control unit 120 may transmit a message including availability information.

[0140] Here, control unit 120 may control transmission unit 111 to transmit a message including availability information upon expiration of the retransmission timer, even if the prohibition timer is running. Alternatively, control unit 120 may stop the prohibition timer upon expiration of the retransmission timer. Control unit 120 may control transmission unit 111 to transmit a message including availability information after the prohibition timer is stopped. Control unit 120 may restart the prohibition timer based on the transmission of the message including availability information. Control unit 120 may reset the timer value and start the prohibition timer.

[0141] In the above-described embodiment, in the third operation example regarding the determination of update notification, the determination based on the distance difference is performed first, and the determination based on the time difference is performed later, but this is not limited to this. The determination based on the time difference may be performed first, and the determination based on the distance difference may be performed later.

[0142] In the above-described embodiment, the UE 100 may determine which determination is to be prioritized, the determination based on the distance difference or the determination based on the time difference. The UE 100 may determine which determination is to be prioritized, for example, depending on the implementation. The UE 100 may receive information specifying which determination is to be prioritized from the base station 200. The UE 100 may determine which determination is to be prioritized based on the information.

[0143] In the above embodiment, the UE 100 may determine whether to perform the update notification by a method other than the above. Also, although the case where the UE 100 executes the retransmission control of the message has been described as an example, the present invention is not limited to this. The UE 100 does not need to execute the retransmission control.

[0144] In the above-described embodiment, an NR-based mobile communication system has been described as an example of the mobile communication system 1. However, the mobile communication system 1 is not limited to this example. The mobile communication system 1 may be a system compliant with the TS of either LTE (Long Term Evolution) or another generation system (e.g., 6th generation) of the 3GPP standard. The base station 200 may be an eNB that provides E-UTRA user plane and control plane protocol termination toward the UE 100 in LTE. The mobile communication system 1 may be a system compliant with the TS of a standard other than the 3GPP standard. The base station 200 may be an IAB (Integrated Access and Backhaul) donor or an IAB node.

[0145] In the above-described embodiment, an NR-based mobile communication system has been described as an example of the mobile communication system 1. However, the mobile communication system 1 is not limited to this example. The mobile communication system 1 may be a system conforming to the TS of either LTE or another generation system (e.g., 6th generation) of the 3GPP standard. The base station 200 may be an eNB that provides E-UTRA user plane and control plane protocol termination for the UE 100 in LTE. The mobile communication system 1 may be a system conforming to the TS of a standard other than the 3GPP standard.

[0146] The steps in the operations of the above-described embodiments do not necessarily have to be executed in chronological order according to the order depicted in the flow diagrams or sequence diagrams. For example, the steps in the operations may be executed in an order different from that depicted in the flow diagrams or sequence diagrams, or may be executed in parallel. Some of the steps in the operations may be deleted, or additional steps may be added to the process. Furthermore, the above-described operational flows are not limited to being executed independently, but may be executed by combining two or more operational flows. For example, some steps of one operational flow may be added to another operational flow, or some steps of one operational flow may be replaced with some steps of another operational flow.

[0147] A program may be provided that causes a computer to execute each process performed by the UE 100 or the base station 200. The program may be recorded on a computer-readable medium. Using the computer-readable medium, the program can be installed on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM (Compact Disk Read Only Memory) or a DVD-ROM (Digital Versatile Disc Read Only Memory). Furthermore, circuits that execute each process performed by the UE 100 or the base station 200 may be integrated, and at least a part of the UE 100 or the base station 200 may be configured as a semiconductor integrated circuit (chip set, SoC (System On Chip)).

[0148] In the above-described embodiments, "transmit" may mean performing processing at least one layer in a protocol stack used for transmission, or may mean physically transmitting a signal wirelessly or via a wired connection. Alternatively, "transmit" may mean a combination of performing processing at least one layer and physically transmitting a signal wirelessly or via a wired connection. Similarly, "receive" may mean performing processing at least one layer in a protocol stack used for reception, or may mean physically receiving a signal wirelessly or via a wired connection. Alternatively, "receive" may mean a combination of processing at least one layer and physically receiving a signal wirelessly or via a wired connection. Similarly, "obtain / acquire" may mean obtaining information from stored information, obtaining information from information received from another node, or obtaining information by generating the information. Similarly, the terms "based on" and "depending on / in response to" do not mean "based only on" or "depending only on," unless expressly stated otherwise. The term "based on" means both "based only on" and "based at least in part on." Similarly, the term "depending on" means both "depending only on" and "depending at least in part on." Similarly, "include" and "comprise" do not mean including only the listed items, but may mean including only the listed items or may include additional items in addition to the listed items. Similarly, in this disclosure, "or" does not mean an exclusive or, but rather a logical or. Furthermore, any reference to elements using designations such as "first," "second," etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements.Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way. In this disclosure, where articles are added by translation, such as a, an, and the in English, these articles shall include the plural unless the context clearly indicates otherwise.

[0149] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0150] (Additional Notes) Additional notes will be given regarding the features of the above-described embodiment.

[0151] (Supplementary Note 1) A communications device comprising: a receiver that receives, from a base station, a radio resource control (RRC) reconfiguration message including information for setting a distance threshold for triggering a notification of an update of route information based on distance and a time threshold for triggering a notification of an update of the route information based on time; and a transmitter that transmits, in response to receiving the RRC reconfiguration message, an RRC reconfiguration complete message to the base station including information indicating that the route information is available, wherein the receiver receives, from the base station, a UE information request message including setting information for reporting the route information; the transmitter transmits, in response to receiving the UE information request message, a UE information response message to the base station including the route information; and the transmitter transmits, to the base station, a UE assistance information message including information indicating that the route information is available based on a determination based on the distance threshold, regardless of a setting of the time threshold.

[0152] (Supplementary Note 2) The communication device according to Supplementary Note 1, wherein the transmitter transmits, to the base station, the UE assistance information message including information indicating that the route information is available, when a three-dimensional distance between location information of the transmitted route information and latest location information held by the communication device exceeds the distance threshold.

[0153] (Supplementary Note 3) The communication device according to Supplementary Note 1 or 2, wherein the transmitter transmits to the base station the UE assistance information message including information indicating that the route information is available based on a determination based on the time threshold, even in a case where the transmitter does not transmit the UE assistance information message including information indicating that the route information is available based on a determination based on the distance threshold.

[0154] (Supplementary Note 4) A base station comprising: a transmitter that transmits, to a communication device, a Radio Resource Control (RRC) reconfiguration message including information for setting a distance threshold for triggering notification of an update of route information based on distance and a time threshold for triggering notification of an update of the route information based on time; and a receiver that receives, in response to the transmission of the RRC reconfiguration message, an RRC reconfiguration complete message from the communication device including information indicating that the route information is available, wherein the transmitter transmits, to the communication device, a UE information request message including setting information for reporting the route information; the receiver receives, in response to the transmission of the UE information request message, a UE information response message including the route information from the communication device; and the receiver receives, from the communication device, a UE assistance information message including information indicating that the route information is available and based on a determination based on the distance threshold, regardless of the setting of the time threshold.

[0155] (Supplementary Note 5) The base station according to Supplementary Note 4, wherein the receiving unit receives the UE assistance information message from the communication device, the UE assistance information message including information indicating that the route information is available, when a three-dimensional distance between location information of the route information transmitted by the communication device and latest location information held by the communication device exceeds the distance threshold.

[0156] (Supplementary Note 6) The base station according to Supplementary Note 4 or 5, wherein the receiver receives, from the communication device, the UE assistance information message including information indicating that the route information is available and based on a determination based on the distance threshold, even when the receiver does not receive the UE assistance information message including information indicating that the route information is available and based on a determination based on the distance threshold.

[0157] (Supplementary Note 7) A communication method executed by a communication device, comprising: receiving, from a base station, a Radio Resource Control (RRC) reconfiguration message including information for setting a distance threshold for triggering a notification of an update of route information based on distance and a time threshold for triggering a notification of an update of the route information based on time; in response to receiving the RRC reconfiguration message, transmitting to the base station an RRC reconfiguration complete message including information indicating that the route information is available; receiving from the base station a UE information request message including setting information for reporting the route information; in response to receiving the UE information request message, transmitting to the base station a UE information response message including the route information; and, regardless of setting of the time threshold, transmitting to the base station a UE assistance information message including information indicating that the route information is available based on a determination based on the distance threshold.

[0158] (Supplementary Note 8) The communication method according to Supplementary Note 7, wherein in the step of transmitting the UE assistance information message, if a three-dimensional distance between location information of the transmitted route information and latest location information held by the communication device exceeds the distance threshold, the UE assistance information message including information indicating that the route information is available is transmitted to the base station.

[0159] (Supplementary Note 9) The communication method according to Supplementary Note 7 or 8, wherein in the step of transmitting the UE assistance information message, even if the UE assistance information message including information indicating that the route information is available based on a determination based on the distance threshold is not transmitted, the UE assistance information message including information indicating that the route information is available based on a determination based on the time threshold is transmitted to the base station.

[0160] (Supplementary Note 10) A communication device comprising: a transmitter that transmits route information regarding a route schedule of the communication device to a base station; and a controller that, when a timestamp report based on the route information is set, determines whether to notify the base station of an update of the route information based on a time difference set by the base station, wherein the controller determines whether to notify the base station of an update of the route information based on a distance difference set by the base station, even when a timestamp report is set.

[0161] (Supplementary Note 11) A communication device according to Supplementary Note 10, comprising a receiving unit that receives at least one of a distance threshold for setting the distance difference and a time threshold for setting the time difference from the base station, wherein the control unit determines to notify an update of the route information when a calculated distance difference calculated based on a new route of the communication device exceeds the distance threshold, or when a calculated time difference calculated based on a scheduled time of the new route of the communication device exceeds the time threshold.

[0162] (Supplementary Note 12) The communication device according to Supplementary Note 11, wherein the control unit determines to notify an update of the route information without making the determination based on the time difference set by the base station when the calculated distance difference exceeds the distance threshold.

[0163] (Supplementary Note 13) The communication device according to Supplementary Note 2, wherein the control unit determines to notify an update of the route information without making the determination based on the distance difference set by the base station when the calculated time difference exceeds the time threshold.

[0164] (Supplementary Note 14) A communication device according to any one of Supplementary Notes 10 to 13, comprising a receiving unit that receives from the base station a distance threshold for setting the distance difference and a time threshold for setting the time difference, wherein the control unit determines to notify an update of the route information when a calculated distance difference calculated based on a new route of the communication device exceeds the distance threshold and when a calculated time difference calculated based on a scheduled time of the new route of the communication device exceeds the time threshold.

[0165] (Supplementary Note 15) The communication device according to Supplementary Note 14, wherein the control unit determines not to notify of an update of the route information without making the determination based on the time difference set by the base station when the calculated distance difference does not exceed the distance threshold.

[0166] (Supplementary Note 16) The communication device according to any one of Supplementary Notes 10 to 15, wherein, when the timestamp is not reported based on the route information, the control unit does not make the determination based on the time difference set by the base station, but makes the determination based on the distance difference set by the base station.

[0167] (Supplementary Note 17) A communication method executed by a communication device, comprising: a step of transmitting route information relating to a route schedule of the communication device to a base station; and a step of determining, when a timestamp report based on the route information is set, whether to notify the base station of an update of the route information based on a time difference set by the base station, wherein in the determining step, even when a timestamp report is set, it is determined whether to notify the base station of an update of the route information based on a distance difference set by the base station.

Claims

1. A communication device (100), A receiving unit (112) receives a radio resource control (RRC) reset message from a base station (200) which includes information for setting a distance threshold for triggering a notification of route information update based on distance and a time threshold for triggering a notification of route information update based on time, The system includes a transmitting unit (111) that, upon receiving the RRC reset message, transmits an RRC reset completion message to the base station, which includes information indicating that the routing information is available. The receiving unit receives a UE information request message from the base station, which includes setting information regarding the reporting of the route information. The transmitting unit, upon receiving the UE information request message, transmits a UE information response message including the routing information to the base station. Regardless of the setting of the time threshold, the transmitting unit transmits a UE supplementary information message to the base station, which includes information indicating that the route information is available, based on a determination made based on the distance threshold. Communication device.

2. If the three-dimensional distance between the location information of the transmitted route information and the latest location information held by the communication device exceeds the distance threshold, the transmitting unit transmits the UE auxiliary information message to the base station, which includes information indicating that the route information is available. The communication device according to claim 1.

3. Even if the transmitting unit does not transmit the UE supplementary information message containing information indicating that the route information is available based on the determination based on the distance threshold, it transmits the UE supplementary information message containing information indicating that the route information is available to the base station based on the determination based on the time threshold. The communication device according to claim 1 or 2.

4. If a predetermined period has elapsed since the RRC reset completion message was sent to the base station, and no acknowledgment has been received for the RRC reset completion message, the control unit (120) is further comprising a control unit (120) that performs retransmission control to send information indicating that the routing information is available. The communication device according to claim 1 or 2.

5. If the control unit receives the acknowledgment before the predetermined period has elapsed, it shall discontinue the retransmission control. The communication device according to claim 4.

6. The aforementioned acknowledgment is transmitted in a layer lower than the RRC layer. The communication device according to claim 4.

7. The receiving unit receives a timer value indicating the predetermined period from the base station, The control unit, Based on the transmission of the RRC reset completion message, the timer with the set timer value is started. Based on the expiration of the timer, the retransmission control is executed. The communication device according to claim 4.

8. When the control unit receives the timer value, it deems that the communication device is permitted to send a message that includes information indicating that routing information is available, at any time it chooses to send. The communication device according to claim 7.

9. Base station (200), A transmitting unit (211) transmits a radio resource control (RRC) reset message to a communication device (100) which includes information for setting a distance threshold for triggering a notification of route information update based on distance and a time threshold for triggering a notification of route information update based on time, The system includes a receiving unit (212) that receives an RRC reset completion message from the communication device in response to the transmission of the RRC reset message, which includes information indicating that the routing information is available. The transmitting unit transmits a UE information request message containing setting information for reporting the route information to the communication device. The receiving unit receives a UE information response message containing the routing information from the communication device in response to the transmission of the UE information request message. The receiving unit receives from the communication device a UE auxiliary information message from which information is available, regardless of the setting of the time threshold, and which includes information indicating that the route information is available and is determined based on the distance threshold. Base station.

10. The receiving unit receives the UE auxiliary information message from the communication device, which includes information indicating that the route information is available, if the three-dimensional distance between the location information of the route information transmitted by the communication device and the latest location information held by the communication device exceeds the distance threshold. The base station according to claim 9.

11. Even if the receiving unit does not receive the UE auxiliary information message from the communication device which includes information indicating that the route information is available and which is determined based on the distance threshold, the receiving unit will receive the UE auxiliary information message from the communication device which includes information indicating that the route information is available and which is determined based on the time threshold. The base station according to claim 9 or 10.

12. The receiving unit receives information indicating that the route information transmitted by the execution of retransmission control is available from the communication device which has not received an acknowledgment for the RRC reset completion message even after a predetermined period has elapsed since the RRC reset completion message was transmitted to the base station. The base station according to claim 9 or 10.

13. A communication method performed by a communication device (100), The steps include receiving a radio resource control (RRC) reset message from a base station (200) that includes information for setting a distance threshold for triggering a notification of route information update based on distance and a time threshold for triggering a notification of route information update based on time, In response to receiving the RRC reset message, the steps include sending an RRC reset completion message to the base station, which includes information indicating that the routing information is available; The steps include receiving a UE information request message from the base station that includes configuration information regarding the reporting of the aforementioned routing information, The steps include: sending a UE information response message containing the routing information to the base station in response to receiving the UE information request message; Regardless of the setting of the time threshold, the step of sending a UE auxiliary information message to the base station, which includes information indicating that the route information is available based on a determination based on the distance threshold. Communication method.

14. In the step of transmitting the UE auxiliary information message, if the three-dimensional distance between the location information of the transmitted route information and the latest location information held by the communication device exceeds the distance threshold, the UE auxiliary information message, which includes information indicating that the route information is available, is transmitted to the base station. The communication method according to claim 13.

15. In the step of transmitting the UE supplementary information message, even if the UE supplementary information message containing information indicating that the route information is available is not transmitted based on the determination based on the distance threshold, the UE supplementary information message containing information indicating that the route information is available is transmitted to the base station based on the determination based on the time threshold. The communication method according to claim 13 or 14.

16. If a predetermined period of time has elapsed since the RRC reset completion message was sent to the base station, and no acknowledgment for the RRC reset completion message has been received, the claim further comprises the step of performing retransmission control to send information indicating that the routing information is available. The communication method according to claim 13 or 14.

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