Base station device, communication device, control method, and program

Abstract

To provide a mechanism that restricts a multihop configuration in an IAB network environment that may include mobile IAB.SOLUTION: A base station device is disclosed, which relates to provision of a communication service, and comprises: acquisition means that acquires a connection request from an external device for one integrated access and backhaul (IAB) node; and processing means that, when the one IAB node is a mobile IAB node and the external device is another IAB node, performs processing of rejecting the connection request.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a base station device, a communication device, a control method, and a program. [Background technology]

[0002] In 3GPP (3rd Generation Partnership Project) (registered trademark), standardization of IAB (Integrated Access and Backhaul) as a communication technology for backhaul is progressing.

[0003] The IAB technology is a technology that uses millimeter wave wireless communication in the 28 GHz band or the like, which is used for access communication between a base station and user equipment (UE), as backhaul communication (Patent Document 1).

[0004] In a backhaul communication network using IAB technology (hereinafter referred to as an IAB network), relay devices called IAB nodes relay (base station relay) communications from IAB donors, which are equivalent to conventional base stations, to the destination UE. IAB nodes have the same functionality as base stations that accept connections from UEs.

[0005] In the next Release-18, 3GPP plans to formulate specifications for mobile IAB to realize Vehicle-Mounted Relay in response to the demand for improved 5G cellular coverage and connectivity. Vehicle-Mounted Relay is a technology in which an IAB node mounted on a vehicle relays signals from a base station.

[0006] In the discussions on the formulation of this specification, it is considered that requirements unique to mobility scenarios in which the IAB node and UE move relative to each other will arise and cannot be met by conventional specifications. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2019-534625 Summary of the Invention [Problem to be solved by the invention]

[0008] For example, if the mobile IAB allows a multi-hop configuration, an IAB node may be connected to the mobile IAB node in a state where an IAB network including the mobile IAB node is formed. In this state, if the upper mobile IAB node moves together with the vehicle, it may be difficult to maintain the IAB network. As a result, it may become impossible to continue the communication services of the subordinate IAB nodes and UEs. In addition, depending on the configuration of the IAB network, there may be cases where it is not desirable to connect an IAB node to the subordinate. In this regard, even in the current standard, no mechanism is proposed for restricting a multi-hop configuration in an IAB network environment that may include a mobile IAB.

[0009] The present invention has been made in consideration of at least one of the above problems. As one aspect of the present invention, an object of the present invention is to provide a mechanism for restricting a multi-hop configuration in an IAB network environment that may include a mobile IAB. [Means for solving the problem]

[0010] A base station device according to one aspect of the present invention is a base station device related to the provision of a communication service, An acquisition means for acquiring a connection request from an external device to an IAB (Integrated Access and Backhaul) node; A processing means for performing a process of rejecting the connection request at least when the one IAB node is a mobile IAB node and the external device is another IAB node; The present invention is characterized by comprising: Effect of the Invention

[0011] According to one aspect of the present invention, it is possible to provide a mechanism for restricting multi-hop configuration in an IAB network environment that may include a mobile IAB. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram illustrating an example of a mobile communication system in the present embodiment. [Figure 1A] FIG. 2 is an explanatory diagram showing another situation in the mobile communication system of FIG. [Diagram 2] FIG. 2 is a hardware functional block diagram of a mobile IAB node in the present embodiment. [Figure 3A] FIG. 2 is a software functional block diagram of a mobile IAB node in this embodiment. [Figure 3B] FIG. 2 is a software functional block diagram of an IAB donor in this embodiment. [Figure 4] FIG. 11 is a connection control processing sequence diagram of a mobile IAB node and an IAB node in the first embodiment. [Diagram 5] 13 is a processing flow of an IAB donor in response to a connection request from an external device in embodiment 1. [Figure 6] FIG. 11 is a connection control processing sequence diagram of a mobile IAB node and an IAB node in the second embodiment. [Figure 6A] 13 is a processing flow of an IAB donor in response to a connection request from an external device in the second embodiment. [Figure 7] 13 is a connection control processing flow of a mobile IAB node and an IAB node in embodiment 3. [Figure 7A] 13 is a processing flow of an IAB donor in response to a connection request from an external device in embodiment 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Each embodiment will be described in detail below with reference to the accompanying drawings.

[0014] [Embodiment 1] FIG. 1 is a diagram showing an example of a mobile communication system in this embodiment.

[0015] In the example shown in FIG. 1, in a network providing public network communication services to cell coverages 101 and 102, there are IAB donors 103 and 104 that provide connections to a CN 100.

[0016] In cell coverage 101, IAB nodes 105-107 and a mobile IAB node 108 are wirelessly connected to an IAB donor 103 to form an IAB network. In Fig. 1, CN stands for Core Network, and is responsible for various processes such as authentication of terminals UEs 109-114.

[0017] IAB donor 103 comprehensively controls each of IAB nodes 105 to 107 and mobile IAB node 108, and forms cell coverage 101 that the station covers. IAB donor 104 similarly forms cell coverage 102 that the station covers.

[0018] In the IAB network, communication packets that conform to the BAP data PDU format (hereinafter referred to as BAP data packets) are used as communication packets. PDU is an abbreviation for Protocol Data Unit.

[0019] For example, an IP packet addressed to the UE 109 from the CN 100 is encapsulated into a BAP data packet in the IAB donor 103 and forwarded to the IAB node 105. The forwarded BAP data packet is converted back into an IP packet in the IAB node 105 and delivered to the destination UE 109.

[0020] Similarly, an IP packet from the UE 109 is also encapsulated into a BAP data packet at the IAB node 105. Then, the packet is converted back into an IP packet at the IAB donor 103 and transferred to the CN 100. Note that IP is an abbreviation for Internet Protocol.

[0021] The IAB nodes 105 to 107 are fixed communication nodes and are connected to the IAB donor 103 .

[0022] The mobile IAB node 108 is also connected to the IAB donor 103. In this case, the IAB donor 103, the IAB nodes 105 to 107, and the mobile IAB node 108 form an IAB network.

[0023] The mobile IAB node 108 may be a communication node installed in a moving object such as a train, a bus, or a taxi. The moving object is not limited to an object moving on a road, but includes an air vehicle. When the mobile IAB node 108 moves beyond the cell coverage 101 to the cell coverage 102, the mobile IAB node 108 changes the connection to be under the control of the IAB donor 104. The transition between base stations is performed via the CN 100.

[0024] UEs 109-112 are connected to IAB nodes 105 and 107. UEs 113-114 are connected to mobile IAB node 108. A moving object equipped with mobile IAB node 108 may move (run) within cell coverage 101 and cell coverage 102 according to a planned route.

[0025] FIG. 2 is a hardware functional block diagram of the mobile IAB node 108 in this embodiment.

[0026] The mobile IAB node 108 includes a control unit 201 , a storage unit 202 , a wireless communication unit 203 , and an antenna control unit 204 .

[0027] The control unit 201 is configured with one or more processors such as a CPU or MPU, and controls the entire communication device by executing a control program read into the RAM, which is the storage unit 202. Each process performed by the control unit 201, which will be described in the flowcharts below, can also be realized using a hardware circuit such as an ASIC or FPGA. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field Programmable Gate Array. The hardware circuit and a processor such as a CPU or MPU can cooperate to realize the process described in the flowcharts below.

[0028] The storage unit 202 stores information used for control by the control unit 201 and information related to communication. For example, the storage unit 202 stores a control program executed by the control unit 201, information on the UE to be connected, connection strength with the IAB donor 103, and various other information.

[0029] The storage unit 202 may include a main storage unit and an auxiliary storage unit. The main storage unit may be, for example, a read only memory (ROM) or a random access memory (RAM). The main storage unit may store or temporarily store programs and data such as an operating system (OS) that is basic software executed by the control unit 201 and application software. The auxiliary storage unit may be, for example, a hard disk drive (HDD) or a solid state drive (SSD), and may store data related to application software. For example, a control program stored in a non-volatile storage area is expanded in a random access memory (RAM) and executed by a processor constituting the control unit 201. In this way, the control unit 201 and the storage unit 202 may function as a so-called computer.

[0030] The storage unit 202 may include a recording medium for storing a predetermined program. The program stored in this recording medium may be installed via a drive device or the like, and the installed predetermined program may be executable by the control unit 201. The recording medium may be of various types. For example, the recording medium may be a recording medium that records information optically, electrically, or magnetically, such as a CD (Compact Disc)-ROM, a flexible disk, or a magneto-optical disk. The recording medium may also be a semiconductor memory that records information electrically, such as a ROM or a flash memory. Note that the recording medium does not include a carrier wave.

[0031] The wireless communication unit 203 performs cellular network communication such as LTE and 5G that conform to the 3GPP standard.

[0032] The antenna control unit 204 controls the antenna used for wireless communication performed by the wireless communication unit 203 .

[0033] Note that, although the hardware has been described assuming the mobile IAB node 108, it is assumed that the IAB nodes 105 to 107 have the same configuration. It is also assumed that the IAB donors 103 and 104 have the same configuration.

[0034] FIG. 3A is a software functional block diagram of the mobile IAB node 108 in this embodiment.

[0035] The software function block 301 is stored in the storage unit 202 and executed by the control unit 201. The software function block 301 includes a signal transmitting unit 302, a signal receiving unit 303, a data storage unit 304, a connection control unit 305, and a signal generating unit 308.

[0036] The signal transmitting unit 302 and the signal receiving unit 303 control the wireless communication unit 203 via the control unit 201, and perform cellular network communication such as LTE and 5G that conforms to the 3GPP standard between the IAB donor 103 and the UEs 113 to 114.

[0037] The data storage unit 304 controls and manages the storage unit 202, and stores the software itself, connection information with the IAB donors 103 and 104, information on the UEs 113 to 114, etc. Information between IAB nodes can be collected by a broadcast signal or a communication packet accompanying various control PDUs of the BAP (hereinafter, BAP control packet).

[0038] The connection control unit 305 controls the antenna control unit 204 via the control unit 201 during wireless communication.

[0039] The signal generation unit 308 manages and issues various signals generated by the connection control unit 305 .

[0040] Note that, although the hardware has been described assuming mobile IAB node 108, IAB nodes 105 to 107 are also assumed to have a similar configuration.

[0041] 3B is a software functional block diagram of the IAB donor 103 in this embodiment. In the following description, the term "corresponding IAB network" refers to the IAB network formed by the IAB donor 103.

[0042] The software function block 401 is stored in the storage unit 202 and executed by the control unit 201. The software function block 401 includes a signal transmitting unit 402, a signal receiving unit 403, a data storage unit 404, a connection control unit 405, and a network configuration information management unit 406.

[0043] The signal transmitting unit 402 and the signal receiving unit 403 control the wireless communication unit 203 via the control unit 201. The signal transmitting unit 402 and the signal receiving unit 403 perform a process of transmitting signals and messages generated by the connection control unit 405, and a process of receiving messages from subordinate UEs.

[0044] The data storage unit 404 controls and manages the storage unit 202, and stores and holds the software itself, connection information with the IAB nodes 105 to 108, information on the UEs 113 to 114, etc. Various information can be collected by broadcast signals, RRC messages, BAP data packets, etc. RRC is an abbreviation for Radio Resource Control, and BAP is an abbreviation for Backhaul Adaptation Protocol.

[0045] The connection control unit 405 controls the antenna control unit 204 via the control unit 201 during wireless communication. The connection control unit 405 performs connection control in the corresponding IAB network based on information managed by the network configuration information management unit 406. Specifically, the connection control unit 405 controls connections between the IAB nodes 105-107, the mobile IAB node 108, and the UEs 113-114 in the corresponding IAB network based on the configuration information of the IAB network, etc.

[0046] The network configuration information management unit 406 manages the configuration information of the corresponding IAB network. The network configuration information management unit 406 may also manage type information of the UE, IAB node, and mobile IAB node making the connection request as part of the configuration information of the IAB network.

[0047] FIG. 4 is a connection control processing sequence diagram between the IAB node 105 and the mobile IAB node 108 in the first embodiment.

[0048] In this embodiment, it is assumed that an IAB node 105 makes a connection change request to a mobile IAB node 108 that has moved closer. A process will be described in which the IAB donor 103 grasps the identification information of the IAB node 105 that is attempting a connection request to the mobile IAB node 108 and controls the connection.

[0049] In S400, the IAB node 105 transmits and receives a broadcast signal. The IAB node 105 can detect the presence of a mobile IAB node 108 approaching the local station from the broadcast information received in S400. The broadcast signal may be, for example, an SSB (SS / PBCH Block). The same applies to the broadcast signals in S401, S402, etc. below.

[0050] In S401, the mobile IAB node 108 transmits and receives a broadcast signal.

[0051] In S402, the IAB donor 103 transmits and receives a notification signal.

[0052] In S403, when the station detects the presence of a mobile IAB node 108 approaching the station, it attempts to connect to the mobile IAB node 108.

[0053] In S404, the IAB node 105 generates a connection request (RRCSetupRequest) to the mobile IAB node 108. The RRCSetupRequest is a message for requesting the establishment of an RRC connection. If the IAB node 105 is a mobile IAB node, identification information indicating that the node is a mobile IAB node is added to the RRCSetupRequest. The identification information addition field can use the spare of the RRCSetupRequest-IEs or the randomValue of the ue-identity, or the spare1 to 6 of the establishmentCause. For example, any of the spare1 to 6 is newly defined as a field such as iab-TypeIndication. Then, when "1" is set in the iab-TypeIndication field, it may be configured to indicate that the node is a mobile IAB node, that is, a mobile IAB node. When "0" is set, it may be configured to indicate that the node is a non-mobile IAB node, that is, a fixed IAB node. In this way, by using a field such as iab-TypeIndication, it becomes possible to notify other devices of information that identifies whether or not the own device is an IAB node to which the own device can move.

[0054] In S405, the mobile IAB node 108 includes the RRC Setup Request received from the IAB node 105 in an INITIAL UL RRC MESSAGE TRASFER MESSAGE and transmits it to the IAB donor 103 (S405, S406).

[0055] In S406, upon receiving the UL RRC MESSAGE TRASFER MESSAGE, the IAB donor 103 extracts the RRCSetupRequest.

[0056] In S407 to S409, the IAB donor 103 continues processing related to RRC Setup between the IAB node 105 and the mobile IAB node 108. The IAB donor 103 includes the RRC Setup message in a DL RRC MESSAGE TRASFER MESSAGE and transmits it to the mobile IAB node 108. The mobile IAB node 108 extracts the RRC Setup from the DL RRC MESSAGE TRASFER MESSAGE and transmits it to the IAB node 105.

[0057] Next, in S410, the IAB node 105 transmits RRCSetupComplete as a second connection request to the mobile IAB node 108. At this time, the IAB node 105 includes an iab-Node indication in the RRCSetupComplete. The mobile IAB node 108 transmits a UL RRC MESSAGE TRASFER MESSAGE including the RRCSetupComplete to the IAB donor 103 (S411).

[0058] In S412, when the IAB donor 103 receives the UL RRC MESSAGE TRASFER MESSAGE, it extracts the RRCSetupComplete. Then, the IAB donor 103 stores the type information of the IAB node 105 based on the iab-Node indication included in the extracted RRCSetupComplete. That is, the IAB donor 103 obtains the identification information of whether or not it is an IAB node from the second connection request, and stores the type information.

[0059] In S413, the IAB donor 103 confirms (understands) that the connection request is from an IAB node based on the type information obtained in S412. In addition, the IAB donor 103 confirms (understands) the request destination based on the fact that the UL RRC MESSAGE TRASFER MESSAGE from the mobile IAB node 108 includes RRCSetupComplete. That is, the IAB donor 103 confirms (understands) that the mobile IAB node 108 is the request destination (connection destination) of the connection request. As a result, in S414, the IAB donor 103 decides to reject the connection request from the IAB node 105. In addition, in a modified example, the processes from S407 to S412 may be omitted. In this case, in S413, the IAB donor 103 may confirm that the connection request is from an IAB node based on the type information obtained in S406.

[0060] In S415 to S417, the IAB donor 103 notifies the IAB node 105 of refusal of connection by RRCReconfiguration via the mobile IAB node 108. Note that the connection may be rejected by using RRCConnectionRelease.

[0061] In S418 and S419, the IAB node 105 notifies the mobile IAB node 108 of acceptance of the refusal with an RRCReconfigurationComplete.

[0062] 5 shows a processing flow of the IAB donor 103 in response to a connection request from an external device in embodiment 1. Note that an external device refers to a device that does not form a corresponding IAB network.

[0063] In S500, the IAB donor 103 acquires type information related to the external device making the connection request. Note that the type information can be acquired in S410 to S412 and confirmed in S413, as described above with reference to FIG.

[0064] In S501, the IAB donor 103 determines whether the external device attempting the connection request is an IAB node based on the type information acquired in S500. The IAB donor 103 may determine that the external device is an IAB node if the above-mentioned RRCSetupComplete includes an iab-Node indication. On the other hand, the IAB donor 103 may determine that the external device is a UE if the above-mentioned RRCSetupComplete does not include an iab-Node indication.

[0065] Also, in S501, the IAB donor 103 determines whether the connection destination related to the connection request is a mobile IAB (mobile IAB node 108 in this example). This determination method may be as described above. More specifically, when the iab-TypeIndication included in the second connection request is a value indicating a mobile IAB node (e.g., "1"), the IAB donor 103 determines that the connection destination related to the connection request is a mobile IAB node.

[0066] If the external device making the connection request is the IAB node 105 and the connection destination related to the connection request is the mobile IAB (in this example, the mobile IAB node 108), the process proceeds to S502. Then, in S502, the IAB donor 103 identifies that the external device is an IAB node and rejects the connection. In this case, the IAB donor 103 notifies the IAB node 105 of the rejection of the connection by RRCReconfiguration, as described above with reference to FIG.

[0067] In S503, the IAB donor 103 identifies that the external device making the connection request is not an IAB node and allows the connection. For example, if the external device making the connection request is a UE, the IAB donor 103 ends the process without sending RRCReconfiguration.

[0068] By the way, in the next Release-18, discussions are being held on the premise that the mobile IAB node will have a single-hop configuration that allows only UEs to connect to the local node. As with conventional IAB technology, a multi-hop configuration in which a mobile IAB node has an IAB node or a mobile IAB node relay node is not rejected. However, it is expected that the complexity of network maintenance will increase by adopting a multi-hop configuration.

[0069] As a comparative example different from the present embodiment, when a connection request from the IAB node 105 to the mobile IAB node 108 is permitted, the following inconvenience may occur. That is, the IAB node 105 is connected to the mobile IAB node 108 in a state where an IAB network including the mobile IAB node 108 is formed. In this state, if the upper mobile IAB node 108 moves, it may become difficult to maintain the IAB network. As a result, it becomes impossible to continue the communication services of the subordinate IAB nodes 105 and UEs 109, 109.

[0070] In contrast, according to the present embodiment, it is possible to reduce the inconvenience that may occur in such a comparative example. That is, by rejecting a connection request from the IAB node 105 to the mobile IAB node 108, it is possible to reduce the inconvenience that may occur in such a comparative example.

[0071] In this manner, according to the present embodiment, a mechanism for appropriately restricting a multi-hop configuration in an IAB network environment including the mobile IAB node 108 can be established.

[0072] [Embodiment 2] In FIG. 1, an IAB network is formed by IAB donor 103 and IAB nodes 105 to 107, and a mobile IAB node 108 attempts to join the IAB network and connect to IAB node 105. The process will be described below.

[0073] The premise of this embodiment is as follows: The IAB network is operating under a load condition close to the allowable load upper limit, and it is defined that the IAB network as a whole will reject connections of the mobile IAB node 108.

[0074] FIG. 6 is a connection control processing sequence diagram of the IAB node 105 and the mobile IAB node 108 in the second embodiment.

[0075] In S600 to S602, the IAB donor 103, the IAB node 105, and the mobile IAB node 108 transmit and receive broadcast signals in the same manner as in the first embodiment.

[0076] In S600, the mobile IAB node 108 learns the presence of the IAB node 105 as a neighboring node from the broadcast signal.

[0077] At S603, the mobile IAB node 108 attempts to connect to the IAB node 105.

[0078] In S604 and S605, a rule (an example of a specific setting) that does not permit the connection of a mobile IAB node is shared among the IAB donors 103 and IAB nodes 105 that form the IAB network. In a modified example, S604 and S605 may be omitted.

[0079] In S606, the mobile IAB node 108 makes a connection request to the IAB node 105. At this time, the mobile IAB node 108 adds its own identification information to the RRCSetupRequest that it issues as a connection request signal. The information added here is defined in the first embodiment.

[0080] Specifically, the mobile IAB node 108 transmits an RRCSetupRequest to the IAB node 105. Then, the IAB node 105 transmits an INITIAL UL RRC MESSAGE TRASFER MESSAGE including the RRCSetupRequest to the IAB donor 103 (S606, S607).

[0081] In S608, when the IAB donor 103 receives the UL RRC MESSAGE TRASFER MESSAGE, the IAB donor 103 extracts the RRCSetupRequest. Then, the IAB donor 103 stores the connection type identification information based on the identification information in the additional field of the extracted RRCSetupRequest.

[0082] In S609, the IAB donor 103 confirms that the connection request is from an IAB node based on the identification information obtained in S608. That is, in S609, the IAB donor 103 confirms that the external device attempting the connection request is a mobile IAB node (mobile IAB node 108) based on the type information obtained in S608. As a result, in S610, the IAB donor 103 decides to reject the connection request from the mobile IAB node 108 to the IAB node 105. Then, in S611, the IAB donor 103 rejects the connection to the mobile IAB node 108 by using RRCReject (S612, S613).

[0083] FIG. 6A shows a processing flow of the IAB donor 103 in response to a connection request from an external device in the second embodiment.

[0084] The process shown in FIG. 6A differs from the process shown in FIG. 5 in relation to the first embodiment in that S501 is replaced by S501A.

[0085] In S501A, the IAB donor 103 determines, based on the identification information acquired in S500, whether the external device attempting the connection request is a mobile IAB node 108. If the external device making the connection request is a mobile IAB node 108, the IAB donor 103 identifies the external device as a mobile IAB node 108 and rejects the connection (S502). On the other hand, if the external device making the connection request is an IAB node (a fixed communication node), the IAB donor 103 permits the current connection request (S503).

[0086] As a comparative example different from this embodiment, when a connection request from the mobile IAB node 108 to the IAB node 105 is permitted, the following inconvenience may occur. That is, the mobile IAB node 108 will be connected in a state where an IAB network including the IAB node 105 has been formed. If the mobile IAB node 108 moves in this state, it may become difficult to maintain the IAB network.

[0087] In contrast, according to the present embodiment, it is possible to reduce the inconvenience that may occur in such a comparative example. That is, by rejecting a connection request from the mobile IAB node 108 to the IAB node, it is possible to reduce the inconvenience that may occur in such a comparative example.

[0088] In this way, according to the second embodiment, as in the first embodiment described above, a mechanism for appropriately restricting a multi-hop configuration in an IAB network environment including the mobile IAB node 108 can be established. Also, according to the second embodiment, the multi-hop configuration can be appropriately restricted based on a preset rule (specifically, a rule that does not permit the connection of the mobile IAB node 108 as an IAB network). Note that the second embodiment illustrates a case in which an iab-TypeIndication is included in an RRC SetupRequest, which is an example of a connection request, and an iab-NodeIndication is included in an RRC SetupComplete, which is an example of a connection request. However, the present invention is not limited to this, and it is also possible to configure so that both the iab-TypeIndication and the iab-NodeIndication are included in the RRC SetupRequest. Also, it is possible to configure so that both iab-TypeIndication and iab-NodeIndication are included in RRC SetupComplete. When the former is adopted, it is possible to determine whether or not a connection can be established at an early stage of the connection, thereby reducing the calculation cost. When the latter is adopted, it is possible to determine whether or not a connection can be established without significantly modifying the current communication standard. In other words, it is possible to transmit information on whether or not a connection can be established by simply adding iab-TypeIndication to the RRC SetupComplete message, which is already defined to include the iab-NodeIndication format.

[0089] The second embodiment can be effectively combined with the first embodiment. In this case, when the request source of the connection request is the mobile IAB node 108 and the request destination is the mobile IAB node 108, the connection request may be rejected. In this embodiment, the case where the IAB donor 103 rejects the connection request is illustrated, but the lower node may be configured to make the judgment of rejection. In this case, the IAB node 105, in which a rule that does not allow the connection of the mobile IAB node is shared in advance, refers to the contents of the connection request (RRC SetupRequest) received from the IAB node 108. Next, the IAB node 105 judges to reject the connection request when the iab-TypeIndication included in the connection request is a value indicating a mobile IAB node (for example, "1"). When it is judged to reject the connection request, the IAB node 105 rejects the connection request by transmitting an RRC reject message, which is a response message to the mobile IAB node 108. On the other hand, if the iab-TypeIndication included in the connection request is not a value indicating a mobile IAB node (e.g., "1"), the IAB node 105 forwards the connection request to the IAB donor 105, which is a higher-level IAB node. The connection process thereafter may be the same as that described in the above embodiment. According to this modified example of embodiment 2, the downstream IAB node can appropriately restrict the multi-hop configuration based on a rule shared in advance (specifically, a rule that does not permit the connection of the mobile IAB node 108 as an IAB network).

[0090] [Embodiment 3] In FIG. 1A, when an IAB network is formed by IAB donor 103 and IAB nodes 105 to 107, a process will be described in which a mobile IAB node 108 attempts to join the IAB network and connect to IAB node 107.

[0091] In the IAB network formed in this embodiment, the number of hops N of IAB nodes is defined. The "N" in the number of hops N is a natural number of 2 or more, and means that the mobile IAB node 108 is not permitted to connect to IAB nodes at the Nth stage or later.

[0092] In the third embodiment, the IAB node configuration hop count N is set to 2 (an example of a threshold value).

[0093] FIG. 7 is a connection control processing sequence diagram of the mobile IAB node 108 and the IAB node 107 in the third embodiment.

[0094] In S700 to S703, the IAB donor 103, the IAB node 107, and the mobile IAB node 108 transmit and receive broadcast signals in the same manner as in the first embodiment.

[0095] In S704, the IAB node 107 notifies the IAB donor 103 of the IAB configuration hop count in its IAB network.

[0096] In this case, the method for finding out the number of hops can be found in Phase 2-2: Routing update of the IAB-node Integration Procedure defined in TS38.401 8.12. In other words, in Phase 2-2: Routing update, when acquiring an IP address, the number of hops in the IAB network can be found out by executing a traceroute, for example.

[0097] This information can be communicated to the IAB donor 103 through the BAP.

[0098] In S705, the IAB network is defined as having an IAB node configuration hop count N=2, and this is notified to the IAB nodes 105 to 107 that configure the IAB network.

[0099] Next, the mobile IAB node 108 transmits an RRCSetupRequest to the IAB node 107. Then, the IAB node 107 transmits an INITIAL UL RRC MESSAGE TRASFER MESSAGE including the RRCSetupRequest to the IAB donor 103 (S706, S707).

[0100] At S708, upon receiving the UL RRC MESSAGE TRASFER MESSAGE, the IAB donor 103 extracts the RRCSetupRequest.

[0101] In S709, the IAB donor 103 grasps the hop count of the IAB node 107 and judges whether to reject the connection based on the identification information of the mobile IAB node 108 attempting the connection request. For example, when the IAB donor 103 receives an INITIAL UL RRC MESSAGE TRASFER MESSAGE including an RRCSetupRequest from the IAB node 107, the following may occur. First, the IAB donor 103 may judge that the hop count of the IAB node that sent the RRCSetupRequest is the hop count of the IAB node 107 + 1 (i.e., 2 in the example of FIG. 7). Then, when the current hop count is the configured hop count N, the IAB donor 103 decides to reject the connection request from the mobile IAB node 108 to the IAB node 107. As a result, in S710, the IAB donor 103 decides to reject the connection request from the mobile IAB node 108 to the IAB node 107. Then, in S711, the IAB donor 103 rejects the connection to the mobile IAB node 108 using an RRCReject (S712, S713). Note that if the external device attempting the connection request is not the mobile IAB node 108 but a UE, the IAB donor 103 may accept the connection request.

[0102] FIG. 7A shows a processing flow of the IAB donor 103 in response to a connection request from an external device in the third embodiment.

[0103] The process shown in FIG. 7A differs from the process shown in FIG. 5 in relation to the first embodiment in that if the determination result in S501 is "YES", the process proceeds to S700 instead of S502.

[0104] In S700, the IAB donor 103 determines whether the current hop count is the configured hop count N. If the current hop count is the configured hop count N, the IAB donor 103 rejects the current connection request (S502). On the other hand, if the current hop count is smaller than the configured hop count N, the IAB donor 103 allows the current connection request (S503).

[0105] In Fig. 7A, the determination process of S501 is the same as the process shown in Fig. 5 in relation to the first embodiment, but may be different. For example, in Fig. 7A, as a process replacing S501, the IAB donor 103 may simply determine whether the external device attempting the connection request is an IAB node based on the type information acquired in S500. That is, in Fig. 7A, it is not necessary to determine whether the connection destination related to the connection request is the mobile IAB node 108.

[0106] However, as a comparative example different from the present embodiment, when a connection request is permitted based on a condition that does not consider the number of hops, the following inconvenience may occur: That is, an IAB network with an excessive number of hops may be formed, and in such a state, the complexity of network maintenance may increase, making it difficult to maintain a stable IAB network.

[0107] In contrast, according to the present embodiment, it is possible to reduce the inconvenience that may occur in such a comparative example. That is, by rejecting a connection request in which the number of hops exceeds the number of configured hops N, it is possible to reduce the inconvenience that may occur in such a comparative example.

[0108] In this way, according to the third embodiment, as in the above-described first embodiment, it is possible to establish a mechanism for appropriately restricting a multi-hop configuration in an IAB network environment including the mobile IAB node 108. Also, according to the third embodiment, it is possible to appropriately restrict a multi-hop configuration based on a preset rule (specifically, a rule that does not permit connection of an IAB node whose hop count exceeds the number of configured hops N).

[0109] Note that the present embodiment 3 can be effectively combined with the above-mentioned embodiment 2. For example, when the present embodiment 3 is effectively combined with the embodiment 2, if the request source of the connection request is the mobile IAB node 108 and the current hop count is the configured hop count N, the connection request may be rejected.

[0110] [Other embodiments] As described in the above embodiment, the transmission and reception of the identification information is assumed to be performed by adding an identification signal in the RRC. That is, the description is given as a processing method equivalent to Phase 1: IAB-MT setup in the IAB-node Integration Procedure, an IAB node connection sequence according to the 3GPP standard defined in TS38.401 8.12. However, the identification may be performed in each phase, such as Phase 2-1: BH RLC channel establishment, Phase 2-2: Routing update, and Phase 3: IAB-DU setup.

[0111] In addition, although the above-described embodiment relates to public network communication services, it may also be applied to local 5G or the like.

[0112] The following supplementary notes are further disclosed regarding the above-described embodiment.

[0113] [Appendix 1] A base station device related to the provision of a communication service, An acquisition means for acquiring a connection request from an external device to an IAB (Integrated Access and Backhaul) node; a processing means for performing a process of rejecting the connection request at least when the one IAB node is a mobile IAB node and the external device is another IAB node; A base station device comprising:

[0114] [Appendix 2] The base station device according to claim 1, wherein the processing means accepts the connection request when the external device is a UE (User Equipment).

[0115] [Appendix 3] 3. The base station device according to claim 1, wherein the connection request includes type information indicating whether the external device is an IAB node or not.

[0116] [Appendix 4] The base station device according to any one of Supplementary Notes 1 to 3, further characterized in that the processing means rejects the connection request when a specific setting is made in the base station device and the external device is a mobile IAB node, whereas it accepts the connection request when the external device is a UE (User Equipment) or a fixed IAB node even when the specific setting is made in the base station device.

[0117] [Appendix 5] 5. The base station device according to claim 1, wherein the connection request includes identification information indicating whether the external device is a mobile IAB node.

[0118] [Appendix 6] The base station device described in any one of Supplementary Notes 1 to 5, wherein the processing means is further characterized in that, when the external device is another IAB node, and when accepting the connection request would cause the number of hops to the other IAB node to exceed a threshold, the processing means rejects the connection request. [Explanation of symbols]

[0119] 101 Cell Coverage 102 cell coverage 103 IAB Donor (An example of base station equipment) 104 IAB donors 105 IAB node (an example of a communication device) 106 IAB node (an example of a communication device) 107 IAB node (an example of a communication device) 108 Mobile IAB node (an example of a communication device) 109~114UE 201 Control unit (an example of a processing means and a request means) 202 Storage section 203 Wireless communication unit (an example of an acquisition means) 204 Antenna control section 301 Software Function Blocks 302 Signal transmitter 303 Signal receiving unit 304 Data Storage Unit 305 Connection control section 308 Signal Generator 401 Software Function Blocks 402 Signal transmitter 403 Signal receiving unit 404 Data Storage Unit 405 Connection control section 406 Network Configuration Information Management Department

Claims

1. Base station equipment related to the provision of communication services, An acquisition means for acquiring an RRCSetupRequest from an external device to one IAB (Integrated Access and Backhaul) node, At a minimum, if one of the IAB nodes is a mobile IAB node and the external device is another IAB node, the processing means performs a process to reject the connection request by the RRCSetupRequest, A base station device characterized by comprising the following features.

2. The processing means, when the external device is a UE (User Equipment), The base station device according to claim 1, characterized in that it accepts the aforementioned connection request.

3. The base station device according to claim 2, characterized in that the connection request includes type information indicating whether or not the external device is an IAB node.

4. The base station device according to claim 1, further characterized in that the processing means rejects the connection request when a specific setting has been made to the base station device and the external device is a mobile IAB node, while accepting the connection request when the specific setting has been made to the base station device and the external device is a UE (User Equipment) or a fixed IAB node.

5. The base station device according to claim 4, wherein the connection request includes identification information indicating whether or not the external device is a mobile IAB node.

6. The processing means further, if the external device is another IAB node and accepts the connection request, the number of hops to the other IAB node exceeds a threshold, The base station device according to any one of claims 1 to 5, characterized in that it rejects the aforementioned connection request.

7. A communication device mounted on a mobile body, or in the form of a mobile body, capable of configuring an IAB (Integrated Access and Backhaul) network, A transmission means for sending an RRCSetupRequest to one IAB node, The system includes a processing means that, when a connection request by the RRCSetupRequest is accepted, provides a communication service to a subordinate UE (User Equipment) via the IAB node, A communication device characterized in that the RRCSetupRequest transmitted by the transmission means is an RRCSetupRequest in which a specific value of one bit is stored for a specific field, and storing the specific value for the specific field indicates that the device is a mobile IAB node.

8. A control method for controlling communication, The acquisition process involves obtaining an RRCSetupRequest from an external device to one IAB (Integrated Access and Backhaul) node, At a minimum, if one of the IAB nodes is a mobile IAB node and the external device is another IAB node, the processing step includes a process to reject the connection request by the RRCSetupRequest, A control method characterized by having the following features.

9. On the computer, The process involves obtaining an RRCSetupRequest from an external device to one IAB (Integrated Access and Backhaul) node, At a minimum, if one of the IAB nodes is a mobile IAB node and the external device is another IAB node, the process includes rejecting the connection request by the RRCSetupRequest, A program to execute.

10. A method for controlling a communication device, The process involves sending an RRCSetupRequest to one IAB (Integrated Access and Backhaul) node, When a connection request via RRCSetupRequest is accepted, the process includes providing a communication service to the subordinate UE (User Equipment) via the IAB node, It has, A control method characterized in that the RRCSetupRequest transmitted in the transmission step is an RRCSetupRequest in which a specific value of 1 bit is stored for a specific field, and storing the specific value for the specific field indicates that the device is a mobile IAB node.

11. In the computer of the communication device, The process involves sending an RRCSetupRequest to one IAB (Integrated Access and Backhaul) node, When a connection request via RRCSetupRequest is accepted, the process includes providing a communication service to the subordinate UE (User Equipment) via the IAB node, A program to execute, The RRCSetupRequest transmitted in the transmission step is an RRCSetupRequest in which a specific value of 1 bit is stored for a specific field, and the program is characterized in that storing the specific value for the specific field indicates that it is a mobile IAB node.

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