First apparatus, second apparatus and method

Abstract

A first device (100A) according to an aspect of the present disclosure comprises an information acquiring unit (141) for acquiring path information indicating at least a movement path of a user equipment for which a handover from the first device to a second device (100B) is performed, and a communication processing unit (145) for transmitting a device-to-device message including the path information to the second device, wherein the device-to-device message is a message concerning a handover.

Description

Cross-reference to related applications

[0005] , , , , ,

[0003] , , , , , , <00​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​3GPP TS 36.331 V15.14.0 (2021-06), “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); protocol specification (Release 15)” [Non-Patent Document 2] 3GPP TSG-RAN WG2 Meeting #101bis Sanya, China, 16 - 20 Apr 2018, R2-1805125, Huawei, HiSilicon, CMCC, Fraunhofer, Nokia, Nokia Shanghai Bell, Lenovo, Motorola Mobility, InterDigital, KDDI, "Discussion on flight path information" [Non-Patent Document 3] 3GPP TSG RAN - RAN-Rel-18 workshop, Online, 2021-06-28 - 2021-07-02, RWS-210190, Ericsson, "Motivation for Rel-18 UAV" [Non-Patent Document 4] 3GPP TSG RAN Rel-18 workshop, Electronic Meeting, June 28 - July 2, 2021, RWS-210254, Lenovo, Motorola Mobility, "Discussion on UAV Swarm Support in NR RAN for Rel-18" [Non-Patent Document 5] 3GPP TSG RAN Rel-18 workshop, Electronic Meeting, June 28- July 2, 2021, RWS-210474, ZTE, Sanechips, "Support of UAV for 5G Advanced" [Overview of the Initiative]

[0007] As a result of the inventor's detailed examination, the following problems were found. Specifically, in the mechanism of Release 15 described in Non-Patent Documents 1 and 2, reporting of route information may lead to a decrease in signaling efficiency. For example, in the above mechanism, since the UE reports route information to the base station each time it hands over a cell, multiple signalings reporting the same route information may occur. As a result, the signaling efficiency may decrease.

[0008] The purpose of this disclosure is to provide a first apparatus, a second apparatus, and a method that can suppress the decrease in signaling efficiency due to the reporting of route information.

[0009] A first device (100A) according to one aspect of the present disclosure includes an information acquisition unit (141) that acquires route information indicating at least the movement path of user equipment to be handed over from the first device to a second device (100B), and a communication processing unit (145) that transmits an inter-device message including the route information to the second device, wherein the inter-device message is a message relating to the handover.

[0010] A second device (100B) according to one aspect of the present disclosure includes a communication processing unit (145) that receives an interdevice message from the first device (100A) that includes route information indicating at least the movement path of user equipment to be handed over from the first device (100A) to the second device, and an information acquisition unit (141) that acquires the route information contained in the interdevice message, wherein the interdevice message is a message relating to a handover.

[0011] A method performed by a first device (100A) according to one aspect of the present disclosure includes obtaining route information that indicates at least the movement path of user equipment to be handed over from the first device to a second device (100B), and transmitting an inter-device message containing the route information to the second device, wherein the inter-device message is a message relating to the handover.

[0012] A method performed by a second device (100B) according to one aspect of the present disclosure includes receiving an interdevice message from the first device (100A) that includes route information indicating at least the movement path of user equipment to be handed over from the first device (100A) to the second device, and obtaining the route information contained in the interdevice message, wherein the interdevice message is a handover message.

[0013] This disclosure makes it possible to suppress the decrease in signaling efficiency caused by the reporting of routing information. However, this disclosure may also produce other effects in lieu of or in conjunction with this effect. [Brief explanation of the drawing]

[0014] [Figure 1] This is an explanatory diagram showing an example of a schematic configuration of the system according to the embodiment of this disclosure. [Figure 2] This is an explanatory diagram illustrating an example of communication control based on the movement path of user equipment according to the embodiments of this disclosure. [Figure 3] This block diagram shows an example of a schematic functional configuration of a base station according to the embodiments of this disclosure. [Figure 4] This block diagram shows an example of a schematic hardware configuration of a base station according to an embodiment of the present disclosure. [Figure 5] This block diagram shows an example of a schematic functional configuration of a user device according to an embodiment of this disclosure. [Figure 6] This block diagram shows an example of a schematic hardware configuration of user equipment according to an embodiment of this disclosure. [Figure 7]It is an explanatory diagram showing an example of an inter-base station message including route information according to an embodiment of the present disclosure. [Figure 8] It is a sequence diagram for explaining an example of a schematic flow of processing according to an embodiment of the present disclosure. [Figure 9] It is a sequence diagram for explaining an example of a schematic flow of processing according to a third modification of an embodiment of the present disclosure.

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the present specification and drawings, for elements that can be similarly described, duplicate description may be omitted by assigning the same reference numerals.

[0016] The description will be made in the following order. 1. System configuration 2. Base station configuration 3. User equipment configuration 4. Operation example 5. Modification example

[0017] <1. System configuration> Referring to FIG. 1, an example of the configuration of a system 1 according to an embodiment of the present disclosure will be described. Referring to FIG. 1, the system 1 includes a base station 100A, a base station 100B, and a user equipment (UE) 200.

[0018] For example, the system 1 is a system compliant with the technical specifications (Technical Specification: TS) of 3GPP. More specifically, for example, the system 1 is a system compliant with the TS of 5G or NR (New Radio). Of course, the system 1 is not limited to this example. For example, the system 1 may be a system compliant with the TS of LTE, LTE-A (LTE Advanced), or 4G.

[0019] (1) Base station 100 Base stations 100 (for example, base stations 100A and 100B) are nodes of the Radio Access Network (RAN) and communicate with UEs (for example, UE200) located within the coverage area 10 of base station 100.

[0020] For example, base station 100 communicates with UE (e.g., UE200) using a RAN protocol stack. For example, this protocol stack includes RRC (Radio Resource Control), SDAP (Service Data Adaptation Protocol), PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and physical (PHY) layer protocols. Alternatively, the above protocol stack may include only some of these protocols, rather than all of them.

[0021] For example, base station 100 is a gNB. A gNB is a node that provides NR user plane and control plane protocol terminations towards the UE and is connected to 5GC (5G Core Network) via an NG interface. Alternatively, base station 100 may be an en-gNB. An en-gNB is a node that provides NR user plane and control plane protocol terminations towards the UE and operates as a secondary node in EN-DC (E-UTRA-NR Dual Connectivity).

[0022] The base station 100 may include multiple nodes. These multiple nodes may include a first node that hosts the higher layer included in the protocol stack and a second node that hosts the lower layer included in the protocol stack. The higher layer may include RRC, SDAP, and PDCP, and the lower layer may include RLC, MAC, and PHY layers. The first node may be a CU (central unit), and the second node may be a DU (Distributed Unit). The multiple nodes may also include a third node that performs processing below the PHY layer, and the second node may perform processing above the PHY layer. The third node may be a RU (Radio Unit).

[0023] Alternatively, base station 100 may be one of the above-mentioned multiple nodes, or it may be connected to other units among the above-mentioned multiple nodes.

[0024] Base station 100 may be an IAB (Integrated Access and Backhaul) donor or IAB node.

[0025] Furthermore, base station 100 communicates with other base stations via the Xn interface. The Xn control plane (Xn-C) is used for signaling between adjacent base stations. For example, Xn-C signaling is based on XnAP (Xn Application Protocol). The Xn user plane (Xn-U) is used for transmitting application data between adjacent base stations.

[0026] (2) UE200 The UE200 communicates with the base station. For example, the UE200 communicates with the base station 100 when it is located within the coverage area 10 of the base station 100.

[0027] For example, UE200 communicates with a base station (e.g., base station 100) using the protocol stack described above.

[0028] In particular, the UE200 is mounted on a moving object. For example, the moving object may be an aircraft such as a UAV, or a vehicle such as an autonomous vehicle or a manually driven vehicle with navigation capabilities. A moving path may be pre-configured for the moving object. By reporting this moving path to the network (i.e., base station 100), the UE200 can benefit from communication control based on the moving path. This reporting of the moving path may be supported, for example, by a Flight Path mechanism, or by other moving path reporting mechanisms.

[0029] Referring to the example in Figure 2, for example, UE200 reports its configured travel path to base station 100. Based on the future position of UE200 estimated from the reported travel path, base station 100 pre-processes, for example, for handover or beamforming. This makes it possible to perform communication control appropriate to the estimated position when UE200 arrives at that position.

[0030] <2. Base station configuration> Referring to Figures 3 and 4, an example of the configuration of base station 100 (base station 100A and base station 100B) according to the embodiment of this disclosure will be described.

[0031] (1) Functional configuration First, an example of the functional configuration of a base station 100 according to the embodiment of this disclosure will be described with reference to Figure 3. Referring to Figure 3, the base station 100 includes a wireless communication unit 110, a network communication unit 120, a storage unit 130, and a processing unit 140.

[0032] The wireless communication unit 110 transmits and receives signals wirelessly. For example, the wireless communication unit 110 receives a signal from the UE and transmits a signal to the UE.

[0033] The network communication unit 120 receives signals from the network and transmits signals to the network.

[0034] The memory unit 130 stores various information for the base station 100.

[0035] The processing unit 140 provides various functions of the base station 100. The processing unit 140 includes an information acquisition unit 141, a control unit 143, and a communication processing unit 145. The processing unit 140 may also include other components besides these. That is, the processing unit 140 can perform operations other than those of these components. The specific operations of the information acquisition unit 141, the control unit 143, and the communication processing unit 145 will be described in detail later.

[0036] For example, the processing unit 140 (communication processing unit 145) communicates with the UE (e.g., UE200) via the wireless communication unit 110. For example, the processing unit 140 (communication processing unit 145) communicates with other nodes (e.g., network nodes in the core network or other base stations) via the network communication unit 120.

[0037] (2) Hardware configuration Next, with reference to Figure 4, an example of the hardware configuration of a base station 100 according to an embodiment of this disclosure will be described. Referring to Figure 4, the base station 100 comprises an antenna 181, an RF (radio frequency) circuit 183, a network interface 185, a processor 187, a memory 189, and a storage 191.

[0038] Antenna 181 converts a signal into radio waves and radiates the radio waves into space. Antenna 181 also receives radio waves in space and converts the radio waves into signals. Antenna 181 may include a transmitting antenna and a receiving antenna, or it may be a single antenna for both transmitting and receiving. Antenna 181 may be a directional antenna and may include multiple antenna elements.

[0039] The RF circuit 183 performs analog processing on the signals transmitted and received via the antenna 181. The RF circuit 183 may include a high-frequency filter, amplifier, modulator, and low-pass filter, etc.

[0040] The network interface 185 is, for example, a network adapter that sends signals to and receives signals from the network.

[0041] Processor 187 performs digital processing of signals transmitted and received via antenna 181 and RF circuit 183. This digital processing includes processing of the RAN protocol stack. Processor 187 also processes signals transmitted and received via network interface 185. Processor 187 may include multiple processors or may be a single processor. The multiple processors may include a baseband processor that performs the above digital processing and one or more processors that perform other processing.

[0042] Memory 189 stores programs executed by the processor 187, parameters related to those programs, and various other information. Memory 189 may include at least one of ROM (Read Only Memory), EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), RAM (Random Access Memory), and flash memory. All or part of memory 189 may be contained within the processor 187.

[0043] The storage device 191 stores various types of information. The storage device 191 may include at least one of an SSD (Solid State Drive) and an HDD (Hard Disc Drive).

[0044] The wireless communication unit 110 may be implemented by an antenna 181 and an RF circuit 183. The network communication unit 120 may be implemented by a network interface 185. The storage unit 130 may be implemented by a storage device 191. The processing unit 140 may be implemented by a processor 187 and a memory 189.

[0045] Part or all of the processing unit 140 may be virtualized. In other words, part or all of the processing unit 140 may be implemented as a virtual machine. In this case, part or all of the processing unit 140 may operate as a virtual machine on a physical machine (i.e., hardware) including a processor and memory, and a hypervisor.

[0046] Considering the above hardware configuration, the base station 100 may include a memory for storing a program (i.e., memory 189) and one or more processors capable of executing the program (i.e., processor 187), and the one or more processors may execute the program to perform the operation of the processing unit 140. The program may also be a program that causes the processor to perform the operation of the processing unit 140.

[0047] <3. User Equipment Configuration> An example of the configuration of the UE200 according to the embodiment of this disclosure will be described with reference to Figures 5 and 6.

[0048] (1) Functional configuration First, an example of the functional configuration of the UE200 according to the embodiment of this disclosure will be described with reference to Figure 5. Referring to Figure 5, the UE200 comprises a wireless communication unit 210, a storage unit 220, and a processing unit 230.

[0049] The wireless communication unit 210 transmits and receives signals wirelessly. For example, the wireless communication unit 210 receives a signal from a base station and transmits a signal to the base station. For example, the wireless communication unit 210 receives a signal from another UE and transmits a signal to another UE.

[0050] The memory unit 220 stores various information for the UE200.

[0051] The processing unit 230 provides various functions of the UE200. The processing unit 230 includes an information acquisition unit 231, a control unit 233, and a communication processing unit 235. The processing unit 230 may also include other components besides those listed above. That is, the processing unit 230 can perform operations other than those of these components. The specific operations of the information acquisition unit 231, the control unit 233, and the communication processing unit 235 will be described in detail later.

[0052] For example, the processing unit 230 (communication processing unit 235) communicates with a base station (e.g., base station 100A and base station 100B) or another UE via the wireless communication unit 210.

[0053] (2) Hardware configuration Next, an example of the hardware configuration of the UE200 according to an embodiment of the present disclosure will be described with reference to Figure 6. Referring to Figure 6, the UE200 comprises an antenna 281, an RF circuit 283, a processor 285, a memory 287, and a storage 289.

[0054] Antenna 281 converts a signal into radio waves and radiates the radio waves into space. Antenna 281 also receives radio waves in space and converts the radio waves into signals. Antenna 281 may include a transmitting antenna and a receiving antenna, or it may be a single antenna for both transmitting and receiving. Antenna 281 may be a directional antenna and may include multiple antenna elements.

[0055] The RF circuit 283 performs analog processing on the signals transmitted and received via the antenna 281. The RF circuit 283 may include a high-frequency filter, amplifier, modulator, and low-pass filter, etc.

[0056] The processor 285 performs digital processing of signals transmitted and received via the antenna 281 and the RF circuit 283. This digital processing includes processing of the RAN protocol stack. The processor 285 may include multiple processors or may be a single processor. The multiple processors may include a baseband processor that performs the digital processing and one or more processors that perform other processing.

[0057] Memory 287 stores programs executed by the processor 285, parameters related to those programs, and various other information. Memory 287 may include at least one of ROM, EPROM, EEPROM, RAM, and flash memory. All or part of memory 287 may be contained within the processor 285.

[0058] Storage 289 stores various types of information. Storage 289 may include at least one of an SSD and an HDD.

[0059] The wireless communication unit 210 may be implemented by an antenna 281 and an RF circuit 283. The storage unit 220 may be implemented by a storage device 289. The processing unit 230 may be implemented by a processor 285 and a memory 287.

[0060] The processing unit 230 may be implemented by a System on Chip (SoC) including a processor 285 and memory 287. The SoC may also include an RF circuit 283, and the wireless communication unit 210 may also be implemented by the SoC.

[0061] Considering the above hardware configuration, the UE200 may include a memory for storing a program (i.e., memory 287) and one or more processors capable of executing the program (i.e., processor 285), and these one or more processors may execute the program to perform the operation of the processing unit 230. The program may also be a program that causes the processor to perform the operation of the processing unit 230.

[0062] <4. Example of operation> Referring to Figures 7 and 8, an example of the operation of base station 100A, base station 100B, and UE200 according to the embodiment of this disclosure will be described. Here, base station 100A operates as a first base station, and base station 100B operates as a second base station.

[0063] (1) Operation of base station 100A Base station 100A receives routing information from the connected UE200. When base station 100A performs a handover for UE200, it transmits the routing information of UE200 to base station 100B, the handover destination (hereinafter also referred to as the target). The operation of base station 100A and related information will be described in detail below.

[0064] (1-1) Obtaining route information Base station 100A acquires route information that at least indicates the travel path of UE200. Specifically, base station 100A (communication processing unit 145) receives an RRC message containing route information from UE200. Base station 100A (information acquisition unit 141) acquires the route information contained in the received RRC message.

[0065] More specifically, when base station 100A receives RRC message A from UE200, which contains information indicating the availability of routing information, it sends RRC message B to UE200, which contains routing request information indicating a request for routing information. Then, base station 100A receives RRC message C from UE200, which contains routing information.

[0066] For example, RRC message A is RRC SetupComp, ReestablishmentComp, ResumeComp, ReconfigurationComp, etc. RRC message B is UEInformationRequest, and RRC message C is UEInformationResponse. Also, for example, information indicating the availability of route information is flightPathInfoAvailable or equivalent information, route request information is flightPathInfoReq or equivalent information, and route information is flightPathInfoReport or equivalent information.

[0067] Note that routing information may be obtained from other base stations. For example, routing information may be obtained from other base stations via the Xn interface, as described later.

[0068] (1-2) Handover process (transmission of routing information) Base station 100A performs a handover process for UE200. Specifically, as a handover preparation process, base station 100A (control unit 143) determines whether or not to perform a handover for UE200 based on the Measurement Report from UE200. If base station 100A (communication processing unit 145) performs a handover, it sends an inter-base station message regarding the handover to the target base station 100B. This inter-base station message includes routing information for UE200 that has already been acquired. Then, base station 100A receives a response message from base station 100B to the above inter-base station message. For example, the above handover is an Xn-based handover.

[0069] The above inter-base station message is a message requesting a handover from base station 100B. For example, this inter-base station message may be a Handover Request message sent via the Xn interface, as shown in Information 21 of Figure 7. The Handover Request message is sent to base station 100B by the XnAP. For example, routing information may be included in the UE Context Information, which is an Information Element of the Handover Request message. In this way, by including routing information in the existing handover request message, routing information can be sent to base station 100B without defining a new inter-base station message.

[0070] Furthermore, the above routing information is included in the inter-base station message as RRC-related information. For example, the routing information may be included in the HandoverPreparationInformation message of the Handover Request message, as shown in information 21 in Figure 7. In addition, the routing information may be included in the RRCReconfiguration message of the HandoverPreparationInformation message, as shown in Figure 7. In this way, by including the routing information in the RRC message of the inter-base station message, it becomes possible to explicitly provide the routing information to base station 100B as RRC information (also referred to as RRC context information).

[0071] Note that route information may be included in information elements other than UE Context Information, as shown in Information 21 of Figure 7, or it may be included in information elements other than RRC Context within UE Context Information.

[0072] Furthermore, as part of the handover execution process, base station 100A sends an RRC message containing information about the target base station 100B to UE200. For example, when base station 100A receives a Handover Request Acknowledgement message as a response message to the above inter-base station message, it sends an RRCReconfiguration message to UE200 based on the Handover Request Acknowledgement message. Base station 100A also sends an SN (Sequence Number) Status Transfer message to base station 100B using XnAP.

[0073] (2) Operation of base station 100B During the handover process, base station 100B receives routing information for UE200 from base station 100A, the source of the handover. The operation of base station 100B and related information will be described in detail below. Details that are substantially the same as those described for the operation of base station 100A will be omitted.

[0074] (2-1) Handover process (receiving routing information) Base station 100B receives an interbase station message containing routing information from base station 100A. Specifically, base station 100B (communication processing unit 145) receives an interbase station message containing routing information for UE200 from base station 100A. Base station 100B (information acquisition unit 141) acquires the routing information contained in the received interbase station message. This interbase station message is a handover message.

[0075] The above interbase station message is a Handover Request message. Base station 100B sends a Handover Request Acknowledgement message to base station 100A via XnAP in response to the Handover Request message. Subsequently, base station 100B performs a handover for UE200.

[0076] Note that routing information included in inter-base station messages is optional. Therefore, it is not always included in inter-base station messages.

[0077] (3) Operation of UE200 UE200 reports routing information to base station 100A. Furthermore, if a handover from base station 100A to base station 100B occurs for UE200, UE200 performs the connection procedure to base station 100B. At this time, UE200 does not report routing information to the target base station 100B. The operation of UE200 and related information are described in detail below. Note that detailed explanations of content that is substantially the same as the explanations for the operation of base stations 100A and 100B will be omitted.

[0078] (3-1) Reporting of route information UE200 reports routing information to base station 100A. Specifically, UE200 (information acquisition unit 231) acquires the configured routing information. UE200 (communication processing unit 235) sends an RRC message containing the acquired routing information to base station 100A.

[0079] For example, UE200 has reporting information (e.g., a flag) indicating whether or not it has reported routing information to any of the base stations 100. If UE200 indicates that the reporting information has not been reported, it sends an RRC message containing the routing information to the connected base station 100A.

[0080] More specifically, if routing information has not been reported, UE200 sends the aforementioned RRC message A to base station 100A, which contains information indicating the availability of routing information. When UE200 receives the aforementioned RRC message B from base station 100A, which contains routing request information, it sends the aforementioned RRC message C to base station 100A, which contains routing information. Then, UE200 updates the reporting information to reported.

[0081] On the other hand, if UE200 indicates that the reporting information has already been reported, it does not send an RRC message containing routing information to base station 100A. For example, UE200 refers to the reporting information when the connected base station changes due to a handover. If the reporting information indicates that it has already been reported, UE200 does not send an RRC message to the target base station 100 that contains information indicating the availability of routing information. As a result, routing information is also not sent to the target base station 100.

[0082] If the routing information changes, the reporting information is reset to "not reported." Then, when the opportunity to report arises, the UE200 reports the updated routing information to the connected base station 100.

[0083] (3-2) Handover process The UE200 performs handover processing with the source base station 100A and the target base station 100B. Specifically, as part of the handover preparation process, the UE200 sends a Measurement Report to base station 100A. The UE200 also performs connection procedures with the target base station 100B as part of the handover execution process.

[0084] For example, UE200 performs a Random Access Procedure with base station 100B based on the information about the target base station 100B contained in the RRCReconfiguration message received from base station 100A. Once the connection with base station 100B is complete, UE200 sends an RRCReconfigurationComplete message to base station 100B.

[0085] In a conventional system like Release 15, if routing information is configured on UE200, the above RRCReconfigurationComplete will include flightPathInfoAvailable. Subsequently, in response to a request from base station 100B, UE200 sends an RRC message containing flightPathInfoReport, which is routing information, to base station 100B.

[0086] However, in the embodiments of this disclosure, the routing information of UE200 has already been reported to base station 100A and transmitted from base station 100A to base station 100B. Therefore, UE200 does not need to transmit routing information (and information indicating the availability of routing information) to base station 100B. For example, since the reporting information held by UE200 is updated to "reported" when it is reported to base station 100A, UE200 refers to the reporting information and decides not to transmit to base station 100B.

[0087] (4) Processing flow An example of processing according to the embodiment of this disclosure will be described with reference to Figure 8. Figure 8 shows a case in which route information has already been reported from UE200 to base station 100A.

[0088] UE200 transmits a Measurement Report to base station 100A (S410). For example, UE200 transmits a Measurement Report to base station 100A periodically or triggered by a specific event.

[0089] Base station 100A sends a Handover Request message containing routing information to base station 100B (S420). For example, base station 100A determines whether or not to perform a handover for UE200 based on the Measurement Report received from UE200. If a handover is to be performed, and if base station 100A has already received routing information for UE200 (e.g., flightPathInfoReport), it sends a Handover Request message containing routing information to base station 100B using XnAP.

[0090] Base station 100B sends a Handover Request Acknowledgement message to base station 100A (S430). For example, when base station 100B receives a Handover Request message, it stores the routing information contained in the Handover Request message as RRC context information for UE200. Then, base station 100B sends a Handover Request Acknowledgement message containing a HandoverCommand message that encapsulates the RRCReconfiguration message to base station 100A using XnAP.

[0091] Base station 100A sends an RRCReconfiguration message to UE200 (S440). For example, base station 100A sends an RRCReconfiguration message to UE200 based on the received Handover Request Acknowledgement message.

[0092] Base station 100A sends an SN Status Transfer message to base station 100B (S450). For example, base station 100A sends an SN Status Transfer message containing information about the Sequence Number status to base station 100B using XnAP.

[0093] UE200 and base station 100B execute the Random Access Procedure (S460). For example, UE200 and base station 100B execute the Random Access Procedure based on the information received from base station 100A in S450 and S460, respectively.

[0094] UE200 sends an RRCReconfigurationComplete message to base station 100B (S470). For example, since UE200 has already reported routing information to base station 100A, it sends an RRCReconfigurationComplete message to base station 100B that does not include information indicating the availability of routing information. Naturally, the RRCReconfigurationComplete message does not include routing information.

[0095] As described above, according to the embodiment of this disclosure, an interbase station message regarding a handover, including routing information of the UE200 performing a handover from base station 100A to base station 100B, is transmitted from base station 100A to base station 100B. Therefore, when a handover occurs, the UE200 can provide routing information to base station 100B without having to report routing information that has already been reported to the source base station 100A to the target base station 100B. In other words, the occurrence of signaling for reporting routing information can be suppressed. Consequently, it becomes possible to suppress the decrease in signaling efficiency due to the reporting of routing information. As a result, the waste of radio resources and power consumption for communication are suppressed.

[0096] <5. Variation> First to fourth modifications according to embodiments of this disclosure will be described with reference to Figures 8 and 9. Two or more of these modifications may be combined.

[0097] (1) First variation: Other base station inter-message In the embodiments of the present disclosure described above, the inter-base station message containing routing information is a message for requesting a handover. However, the inter-base station message containing routing information according to the embodiments of the present disclosure is not limited to this example.

[0098] As a first modification of the embodiments of this disclosure, the interbase station message containing routing information may be a message for sharing the status of sequence numbers.

[0099] More specifically, the message used to share the status of the above sequence number may be an SN Status Transfer message. For example, base station 100A may include routing information in an SN Status Transfer message instead of including it in a Handover Request message.

[0100] For example, in Figure 8, instead of sending a Handover Request message containing a flightPathInfoReport in S420, base station 100A may send an SN Status Transfer message containing a flightPathInfoReport to base station 100B in S450.

[0101] Thus, according to the first modification of the embodiment of this disclosure, the interbase station message containing routing information is a message for sharing the status of the sequence number. Therefore, by transmitting the routing information to base station 100B after the completion of handover preparations, it is possible to avoid the signaling of routing information being wasted if base station 100B, which was requested to perform a handover, is unable to perform the handover.

[0102] (2) Second variation: Sharing routing information with multiple base stations 100B In the embodiments of the present disclosure described above, route information is provided to the base station 100 that is the target of the handover. However, the destination of the route information according to the embodiments of the present disclosure is not limited to this example.

[0103] As a second modification of the embodiment of this disclosure, the interbase station message containing routing information may be transmitted to a plurality of base stations 100.

[0104] Specifically, interbase station messages containing routing information may be transmitted to multiple base stations 100 derived from the travel path indicated by the routing information. For example, base station 100A (control unit 143) derives base station 100B, which will be the handover target, and base station 100C, which is estimated to be a future target, based on the routing information. Base station 100A (communication processing unit 145) transmits a Handover Request message containing routing information to base stations 100B and 100C.

[0105] Thus, according to the second modification of the embodiment of this disclosure, an interbase station message containing routing information is transmitted to a plurality of base stations 100. These plurality of base stations 100 are derived based on the routing information. This makes it possible to provide routing information to base stations 100 on the UE200's travel path even if a handover does not occur due to a communication interruption such as the UE200 being powered off.

[0106] (3) Third variation: Handover based on N2 In the embodiments of the present disclosure described above, the handover process is a handover process based on Xn. However, the handover process according to the embodiments of the present disclosure is not limited to this example.

[0107] As a third modification of the embodiments of this disclosure, handover processing based on N2 may be performed. Specifically, handover processing is performed based on signaling between the base station 100 and the core network via the NG (Next Generation) interface. Inter-base station messages are transmitted indirectly via the NG interface.

[0108] Referring to Figure 9, an example of processing according to a third modified embodiment of the present disclosure will be described. Figure 9 shows a case where route information has already been reported from UE200 to base station 100A. Processing that is substantially the same as the processing in Figure 8 will not be explained.

[0109] UE200 transmits a Measurement Report to base station 100A (S510).

[0110] Base station 100A sends a Handover Required message containing routing information to the AMF (Access & Mobility Management Function) (S520). For example, base station 100A determines whether or not to perform a handover for UE200 based on the Measurement Report received from UE200. If a handover is to be performed, and if routing information for UE200 (e.g., flightPathInfoReport) has already been received, base station 100A sends a Handover Required message containing routing information to the AMF via NGAP.

[0111] The AMF sends a Handover Request message containing routing information to base station 100B (S530). For example, the AMF obtains routing information contained in the Handover Required message received from base station 100A and sends a Handover Request message containing this routing information to base station 100B, which is the target of the handover in NGAP.

[0112] Base station 100B sends a Handover Request Acknowledgement message to AMF (S540). For example, when base station 100B receives a Handover Request message from AMF, it stores the routing information contained in the Handover Request message as RRC context information for UE200. Base station 100B sends a Handover Request Acknowledgement message containing an RRCConnectionReconfiguration message to AMF via NGAP.

[0113] The AMF sends a Handover Command message to base station 100A (S550). For example, the AMF sends a Handover Command message to base station 100A via NGAP, which includes the RRCConnectionReconfiguration message contained in the Handover Request Acknowledgement message received from base station 100B.

[0114] Base station 100A sends an RRCConnectionReconfiguration message to UE200 (S560). For example, base station 100A sends an RRCConnectionReconfiguration message to UE200 based on a received Handover Command message.

[0115] UE200 sends an RRCConnectionReconfigurationComplete message to base station 100B (S570). For example, since UE200 has already reported routing information to base station 100A, it sends an RRCConnectionReconfigurationComplete message to base station 100B that does not include information indicating the availability of routing information. Naturally, the RRCConnectionReconfigurationComplete message does not include routing information.

[0116] Thus, according to a third modification of the embodiment of this disclosure, interbase station messages containing routing information are transmitted via the NG interface. Therefore, even if the Xn interface is unavailable between base station 100A and base station 100B, routing information can be transmitted to base station 100B, which is the handover target.

[0117] (4) Fourth variation: Clearly indicating the transfer of route information In the embodiments of this disclosure described above, the transfer of routing information between base stations is not notified to the UE200. However, the transfer of routing information according to the embodiments of this disclosure is not limited to this example.

[0118] As a fourth variation of the embodiments of this disclosure, the interbase station message in response to the interbase station message requesting a handover may include handover information indicating that routing information has been handed over.

[0119] Specifically, a Handover Request Acknowledgement message may include a HandoverCommand message that includes an RRCReconfiguration message containing handover information.

[0120] For example, if the UE200 receives an RRCReconfiguration message from base station 100A, the source of the handover, which contains handover information, it sends an RRCReconfigurationComplete message to base station 100B, the target of the handover, which does not contain either information indicating the availability of routing information or routing information itself.

[0121] Thus, according to the fourth modification of the embodiment of this disclosure, the interbase station message in response to the interbase station message requesting a handover includes handover information indicating that the routing information has been handed over. This allows the UE200 to be informed that the routing information has been handed over to base station 100B. Therefore, signaling for reporting routing information can be more reliably suppressed without the UE200 having to retain the reporting information.

[0122] (5) Fifth variation: Compliance with other TS In the examples described above of the embodiments of this disclosure, System 1 is a TS-compliant system for 5G or NR. However, System 1 according to the embodiments of this disclosure is not limited to this example.

[0123] In a fifth modification of the embodiments of this disclosure, System 1 may be a system compliant with another 3GPP TS. For example, System 1 may be a system compliant with an LTE, LTE-A, or 4G TS, and base station 100 may be an eNB (evolved Node B). Alternatively, base station 100 may be an ng-eNB. In another example, System 1 may be a system compliant with a 3G TS, and base station 100 may be a Node B. In yet another example, System 1 may be a system compliant with a next-generation (e.g., 6G) TS.

[0124] Alternatively, System 1 may be a system that conforms to the TS of another standardization body for mobile communications.

[0125] While embodiments of the present disclosure have been described above, the present disclosure is not limited to these embodiments. It will be understood by those skilled in the art that these embodiments are merely illustrative and that various modifications are possible without departing from the scope and spirit of the present disclosure.

[0126] For example, the steps in the process described herein do not necessarily have to be executed chronologically in the order shown in the flowchart or sequence diagram. For example, the steps in the process may be executed in a different order than that shown in the flowchart or sequence diagram, or they may be executed in parallel. Also, some steps in the process may be deleted, or additional steps may be added to the process.

[0127] For example, a method including the operation of one or more components of the apparatus described herein may be provided, and a program for causing a computer to perform the operation of such components may be provided. A computer-readable non-transitory tangible storage medium on which such program is recorded may also be provided. Naturally, such methods, programs, and computer-readable non-transitory tangible storage mediums are also included in this disclosure.

[0128] For example, in this disclosure, user equipment (UE) may be referred to by other names such as mobile station, mobile terminal, mobile device, mobile unit, subscriber station, subscriber terminal, subscriber equipment, subscriber unit, wireless station, wireless terminal, wireless device, wireless unit, remote station, remote terminal, remote device, or remote unit.

[0129] For example, in this disclosure, “transmit” may mean processing at least one layer in the protocol stack used for transmission, or it may mean physically transmitting a signal wirelessly or via a wire. Alternatively, “transmit” may mean a combination of processing at least one layer and physically transmitting a signal wirelessly or via a wire. Similarly, “receive” may mean processing at least one layer in the protocol stack used for reception, or it may mean physically receiving a signal wirelessly or via a wire. Alternatively, “receive” may mean a combination of processing at least one layer and physically receiving a signal wirelessly or via a wire. The at least one layer may be rephrased as at least one protocol.

[0130] For example, in this disclosure, "obtain / acquire" may mean obtaining information from stored information, obtaining information from information received from other nodes, or obtaining information by generating the information.

[0131] For example, in this disclosure, “include” and “comprise” do not mean that only the listed items are included, but that they may include only the listed items or that they may include additional items in addition to the listed items.

[0132] For example, in this disclosure, "or" does not mean exclusive OR, but rather logical OR.

[0133] The technical features included in the embodiments described above may also be expressed as the following features. Of course, this disclosure is not limited to the following features.

[0134] (Feature 1) The first base station (100A), An information acquisition unit (141) acquires route information that at least indicates the movement path of user equipment that is being handed over from the first base station to the second base station (100B), A communication processing unit (145) that transmits an interbase station message containing the aforementioned routing information to the second base station, Equipped with, The aforementioned inter-base station message is a message regarding handover. The first base station.

[0135] (Feature 2) The aforementioned interbase station message is a message requesting a handover from the second base station. The first base station described in Feature 1.

[0136] (Feature 3) The aforementioned routing information is included in the inter-base station message as RRC (Radio Resource Control) related information. The first base station described in Feature 1.

[0137] (Feature 4) The aforementioned inter-base station message is a Handover Request message. The first base station described in any one of the three features.

[0138] (Feature 5) The aforementioned routing information is included in the HandoverPreparationInformation message of the Handover Request. The first base station described in Feature 4.

[0139] (Feature 6) The aforementioned routing information is included in the RRCReconfiguration message of HandoverPreparationInformation. The first base station described in Feature 5.

[0140] (Feature 7) The aforementioned inter-base station message is transmitted via the Xn interface. The first base station described in any one of the features 1 to 6.

[0141] (Feature 8) The second base station (100B), A communication processing unit (145) receives an interbase station message from the first base station (100A) that includes route information indicating at least the movement path of user equipment to be handed over from the first base station (100A) to the second base station, An information acquisition unit (141) that acquires the route information included in the interbase station message, Equipped with, The aforementioned inter-base station message is a message regarding handover. The second base station.

[0142] (Feature 9) A method performed by the first base station (100A), To obtain route information that at least indicates the movement path of user equipment during a handover from the first base station to the second base station (100B), Sending an interbase station message containing the aforementioned routing information to the second base station, Includes, The aforementioned inter-base station message is a message regarding handover. method.

[0143] (Feature 10) A method performed by a second base station (100B), The first base station (100A) receives an interbase station message from the first base station (100A) that includes route information indicating at least the movement path of user equipment to be handed over from the first base station (100A) to the second base station, To obtain the routing information contained in the interbase station message, Includes, The aforementioned inter-base station message is a message regarding handover. method.

[0144] (Feature 11) To obtain route information that at least indicates the movement path of user equipment during a handover from the first base station (100A) to the second base station (100B), Sending an interbase station message containing the aforementioned routing information to the second base station, A program that causes a computer to execute, The aforementioned inter-base station message is a message regarding handover. program.

[0145] (Feature 12) The first base station receives an interbase station message from the first base station (100A) that includes route information indicating at least the movement path of user equipment to be handed over from the first base station (100A) to the second base station (100B), To obtain the routing information contained in the interbase station message, A program that causes a computer to execute, The aforementioned inter-base station message is a message regarding handover. program.

[0146] (Feature 13) To obtain route information that at least indicates the movement path of user equipment during a handover from the first base station (100A) to the second base station (100B), Sending an interbase station message containing the aforementioned routing information to the second base station, A computer-readable, non-transitional, tangible recording medium that stores a program that causes a computer to execute a program, The aforementioned inter-base station message is a message regarding handover. A non-transitional, tangible recording medium.

[0147] (Feature 14) The first base station receives an interbase station message from the first base station (100A) that includes route information indicating at least the movement path of user equipment to be handed over from the first base station (100A) to the second base station (100B), To obtain the routing information contained in the interbase station message, A computer-readable, non-transitional, tangible recording medium that stores a program that causes a computer to execute a program, The aforementioned inter-base station message is a message regarding handover. A non-transitional, tangible recording medium.

Claims

1. The first base station, If routing information for the user device has not been reported since connecting to the user device, the system receives one of the following messages from the user device: a message indicating completion of RRC (Radio Resource Control) connection re-establishment, a message indicating completion of RRC connection resumption, or a message indicating completion of RRC reconfiguration, which includes information indicating that the user device has available routing information for the user device. A communication processing unit that sends a UEInformationRequest message containing information for requesting the transmission of the aforementioned routing information to the user device, A control unit that determines whether to perform a handover from the first base station to the second base station with respect to the user equipment, Equipped with, The aforementioned communication processing unit, If the user device has the available routing information, in response to the transmission of the UEInformationRequest message containing information for requesting the transmission of the routing information, the user device receives a UEInformationResponse message containing the routing information. If it is decided to perform the aforementioned handover, the HandoverPreparationInformation message will include the routing information. The HandoverPreparationInformation message, including the routing information, is transmitted to the second base station via control plane signaling of the Xn interface using XnAP (Xn application protocol). The first base station.

2. The aforementioned route information includes information on the flight path or travel path. The base station according to claim 1.

3. A method performed by the first base station, If routing information for the user device has not been reported since connecting to the user device, the system receives one of the following messages from the user device: a message indicating completion of RRC (Radio Resource Control) connection re-establishment, a message indicating completion of RRC connection resumption, or a message indicating completion of RRC reconfiguration, which includes information indicating that the user device has available routing information for the user device. A UEInformationRequest message containing information for requesting the transmission of the aforementioned routing information is sent to the user device. A decision is made regarding the user equipment to perform a handover from the first base station to the second base station. If the user device has the available routing information, in response to the transmission of the UEInformationRequest message containing information for requesting the transmission of the routing information, the user device receives a UEInformationResponse message containing the routing information. If it is decided to perform the aforementioned handover, the HandoverPreparationInformation message will include the routing information. The HandoverPreparationInformation message, including the routing information, is transmitted to the second base station via control plane signaling of the Xn interface using XnAP (Xn application protocol). method.

4. The aforementioned route information includes information on the flight path or travel path. The method according to claim 3.

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