Communication device, control method, and program

Abstract

To provide a mechanism for identifying an IAB node that can operate as a border IAB node.SOLUTION: A communication device includes determination means for determining whether a node functioning as an IAB node forming an IAB (Integrated Access and Backhaul) network is capable of operating as a border IAB node, which is an IAB node connected to both one IAB network and another IAB network, and transmission means for transmitting a communication message according to the determination result on the basis of the determination result of the determination means.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to 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 simultaneously 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: User Equipment), as backhaul communication (Patent Document 1).

[0004] In backhaul communications using IAB technology, relay devices called IAB nodes relay communications from the IAB donor, which is a base station, via millimeter wave communications. By using IAB technology, it is possible to expand area coverage at lower cost than with conventional wired communications using optical fiber, etc.

[0005] So far, 3GPP has been developing specifications for border IAB nodes up to Rel-17.

[0006] As disclosed in Patent Document 2, a border IAB node is an IAB node that has been discussed since Rel-17 and connects to both IAB networks managed by different IAB donors. The control of the border IAB node is performed by a single IAB donor. Therefore, an IAB node connected to a lower level of the border IAB node connects to an IAB network managed by the IAB donor that controls the border IAB node.

[0007] The advantage of the border IAB node is that the IAB donor that controls the border IAB node can communicate with a device that connects to the border IAB node via an IAB network managed by another IAB donor. This allows the IAB donor that controls the border IAB node to reduce inconvenience when a wireless link failure occurs in the network that it manages. In other words, it becomes possible to communicate by avoiding the wireless link failure by using another IAB network. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Special Publication No. 2019-534625 [Patent Document 2] U.S. Patent Publication No. 2022 / 0394571 Summary of the Invention [Problem to be solved by the invention]

[0009] It is expected that 5G (5th Generation Mobile Communication System) will become widespread in the future, and IAB nodes, especially mobile IAB nodes, will be widely used in general. In this case, there is a possibility that all IAB nodes will not be able to function as border IAB nodes due to device specifications and resource limitations.

[0010] 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 identifying an IAB node that can operate as a border IAB node. [Means for solving the problem]

[0011] A communication device according to one aspect of the present invention includes a determination means for determining whether a node functioning as an IAB node forming one IAB network can operate as a border IAB node, which is an IAB node connected to both the one IAB network and another IAB network; The communication device further comprises a transmitting means for transmitting a communication message according to the result of the determination. Effect of the Invention

[0012] According to one aspect of the present invention, it is possible to provide a mechanism that makes it possible to grasp IAB nodes that can operate as border IAB nodes. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a hardware block diagram of an IAB node and an IAB donor. [Diagram 2] FIG. 2 is a software functional block diagram of an IAB node and an IAB donor. [Diagram 3] 1 is a configuration example of a backhaul communication system (a network using backhaul communication) in a first embodiment. [Figure 4] 1 is an example of a border IAB node processing sequence for an IAB node in the 3GPP standard. [Figure 4A] 11 is a schematic flowchart illustrating an example of an RRC message generation process of an IAB node in the first embodiment. [Diagram 5] 13 is an example of a sequence for determining whether or not a boundary IAB node process is required for an IAB donor in the first embodiment. [Figure 6] 1 is an example of a network participation processing sequence of an IAB node in the 3GPP standard. [Figure 7] 13 is an example of a sequence for determining whether or not a boundary IAB node process is required for an IAB donor in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Each embodiment will be described in detail below with reference to the accompanying drawings.

[0015] Each embodiment described below will be mainly described as an application example in 5G, but each embodiment is not limited to 5G and can also be applied to other next-generation networks such as LTE (Long Term Evolution), 4G, and 6G and later.

[0016] [First embodiment] 1 is a block diagram showing an example of a hardware configuration of an IAB node according to the first embodiment. Note that the hardware configuration of an IAB donor may be similar.

[0017] The hardware configuration 101 of the IAB node includes a control unit 102, a storage unit 103, a wireless communication unit 104, and a communication antenna control unit 105.

[0018] The control unit 102 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 103. Each process performed by the control unit 102, 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. Furthermore, the hardware circuit and a processor such as a CPU or MPU can cooperate to realize the process described in the flowcharts below.

[0019] The storage unit 103 stores information used for control by the control unit 102 and information related to communication. For example, the storage unit 103 stores a control program executed by the control unit 102, and various information such as cell information, connected terminal information, IAB routing information, and location information.

[0020] The storage unit 103 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 102 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 102. In this way, the control unit 102 and the storage unit 103 may function as a so-called computer.

[0021] The storage unit 103 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 102. 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.

[0022] The wireless communication unit 104 performs cellular network communication such as LTE and 5G that conform to the 3GPP standard.

[0023] The communication antenna control unit 105 controls the antenna used for wireless communication performed by the wireless communication unit 104 .

[0024] 2 is a block diagram showing an example of the configuration of a software function block of an IAB node that executes a communication control function. The software configuration of an IAB donor may be similar.

[0025] The software configuration 201 of the IAB node is stored in the storage unit 103 and executed in the control unit 102.

[0026] The software configuration 201 includes a signal transmitting unit 202 , a signal receiving unit 203 , a data storage unit 204 , a connection control unit 205 , an RRC message detecting unit 206 , an RRC message generating unit 207 , and a communication control unit 208 .

[0027] The signal transmitting unit 202 and the signal receiving unit 203 perform cellular network communication such as LTE, 5G, etc., conforming to the 3GPP standard, between a terminal device such as a UE.

[0028] The data storage unit 204 stores and holds the software itself, IAB routing information, information on connected terminals, location information, movement route information, and the like.

[0029] The connection control unit 205 controls an antenna for wireless communication performed by the wireless communication unit 104 .

[0030] The RRC message detection unit 206 detects RRC messages from IAB nodes located in the vicinity (hereinafter also referred to as "neighboring IAB nodes"), UEs, and IAB donors. RRC is an abbreviation for Radio Resource Control.

[0031] The RRC message generating unit 207 generates an RRC message to be transmitted to neighboring IAB nodes, UEs, and IAB donors.

[0032] The communication control unit 208 connects to and disconnects from networks such as LTE and 5G.

[0033] FIG. 3 shows an example of the configuration of a backhaul communication system (a network based on backhaul communication) in this embodiment.

[0034] In backhaul communication, communication from the IAB donor, which is the relay source, is relayed in order from the parent node to the child node. For example, an IAB donor provides backhaul communication to an IAB node connected to itself, and in this case, the IAB donor is the parent node, and the IAB node connected to the IAB donor is the child node.

[0035] 3, the communication system includes IAB donors 302 and 303 connected to a core network (CN) 301. The IAB donors 302 and 303 provide a connection to the CN 301 via backhaul communication to an IAB node connected to them as a child node (i.e., provide backhaul communication).

[0036] The CN and the IAB donor are generally connected by wire through an IP (Internet Protocol) network. The interface between the IAB donors is the Xn interface defined in 3GPP TS38.420.

[0037] An IAB node 304 is connected as a child node to the IAB donor 302. Furthermore, an IAB node 305 and an IAB node 306 are connected to the IAB node 304 as child nodes.

[0038] A UE 307 communicating in a cell area 308 of a cell served by an IAB node 306 can connect to the CN 301 via each IAB donor or IAB node. In the communication system shown in FIG. 3, the UE 307 connects to the CN 301 via the IAB node 306.

[0039] In addition, other IAB donors and IAB nodes other than IAB node 306 can also provide connections to CN 301 for UEs in their cell areas.

[0040] On the other hand, an IAB node 310 is connected as a child node to the IAB donor 303. Furthermore, an IAB node 311 is connected to the IAB node 310 as a child node. In this way, IAB donor 302 and IAB donor 303 are each building their own IAB network.

[0041] Note that the arrangement / configuration of each communication device in the communication system shown in FIG. 3 is one example, and the following description is applicable to other arrangements / configurations.

[0042] In addition, each communication device in the communication system shown in FIG. 3 is a communication device in a 5G access network also called a New Radio (NR) access network. In addition, the radio base station device (IAB donor and IAB node) may also be called a gNB. The following description is also applicable to configurations of other next-generation networks. A typical sequence when an IAB node operates as a border IAB node according to the 3GPP standard is shown in Figure 4. This sequence is defined in 3GPP TS38.401.

[0043] In this sequence diagram, a case is illustrated in which the IAB node 306 operates as a border IAB node, and the IAB node 310 and the IAB donor 303 are selected as the second connection destination.

[0044] IAB node 306 is currently connected to CN 301 via IAB node 304 and IAB donor 302 .

[0045] The UE 307 is connected to the IAB node 306. In this case, the UE 307 transmits and receives downlink data S420 and uplink data S421 to the CN 301 via the IAB node 306, the IAB node 304, and the IAB donor 302.

[0046] First, the NR-DC connection establishment process for the boundary IAB node shown in S401 is performed between the IAB node 306 and the CN 301. The "DC" in NR-DC is an abbreviation for Dual Connectivity. The IAB node 306 collects information on surrounding IAB nodes and base stations, and transmits the connected upper node as a Measurement Report. The IAB donor 302, which is the upper node that receives the Measurement Report, selects a second connection destination to which the IAB node 306 will newly establish a connection based on the Measurement Report, etc. Then, the IAB donor 302 and other devices work together to execute the NR-DC connection establishment process for adding the second connection destination selected by the IAB donor 302 as a secondary node.

[0047] This processing sequence is defined in 3GPP TS37.340, and is performed for the MT (Mobile Termination) portion of the border IAB node 306 .

[0048] Next, in S402, the IAB donor 302 transmits an IAB TRANSPORT MIGRATION MANAGEMENT REQUEST message to the IAB donor 303, which is the second connection destination.

[0049] Upon receiving this request, the IAB donor 303 transmits a DL RRC MESSAGE TRANSFER message, which corresponds to an RRC Reconfiguration message, to the IAB node 310 in S403.

[0050] Next, the IAB node 310 transmits an RRCReconfiguration message to the border IAB node 306 to which it is to connect at S404.

[0051] In response to the above message, the border IAB node 306 transmits an RRC Reconfiguration Complete message to the IAB node 310 in S405. In response to this, the IAB node 310 transmits a UL RRC MESSAGE TRANSFER message corresponding to the RRC Reconfiguration Complete message to the IAB donor 303 (S406).

[0052] Through the above processes, the border IAB node 306 is prepared for connection to the IAB node 310 and the IAB donor 303, which are the second communication path. Then, in S407, wireless layer and backhaul connection processes are performed between the border IAB node 306 and the IAB node 310 and the IAB donor 303, which are the second connection destinations.

[0053] After the above process is completed, in S408, the IAB donor 303 transmits an IAB TRANSPORT MIGRATION MANAGEMENT RESPONSE to the IAB donor 302 as a response to S402.

[0054] Next, in S409, offload processing of uplink and downlink data is performed.

[0055] After the above process is completed, the IAB donor 302 sends an IAB TRANSPORT MIGRATION MANAGEMENT REQUEST message to the IAB donor 303 that is the offload destination (S410). The sending of this message corresponds to the sending of the completion of the offload process. In response, the IAB donor 303 sends an IAB TRANSPORT MIGRATION MANAGEMENT RESPONSE message to the IAB donor 302 (S411).

[0056] Through the series of processes up to this point, as shown in S422 and S423, the IAB node 306 operates as a border IAB node, and uplink and downlink data can be transmitted and received via the second communication path via the IAB node 310.

[0057] Moreover, these processes may be repeated as necessary in S412. In this case, since the NR-DC connection has already been established in S401, the processes from S402 to S411 are performed.

[0058] 4 is a process when the IAB node 306 is a mobile IAB node and operates as a border IAB node. By making the moving mobile IAB node a border IAB node, connection switching during movement can be performed seamlessly.

[0059] However, it is expected that 5G will become widespread and IAB nodes, especially mobile IAB nodes, will be widely used in the future. In this case, it is unlikely that all IAB nodes will be able to become border IAB nodes due to device specifications and resource limitations.

[0060] In addition, if all nodes were to operate as border IAB nodes, the amount of processing between IAB donors and the Central Unit (CU) would also increase, which could lead to an increased system load.

[0061] Therefore, with reference to the following Figures 4A and 5, a mechanism will be described in which the IAB donor 302 side can explicitly distinguish IAB nodes that do not operate as border IAB nodes.

[0062] Fig. 4A is a schematic flowchart showing an example of an RRC message generation process executed on the mobile IAB node 306 side. The process shown in Fig. 4A may be executed at any timing under a situation where the mobile IAB node 306 is not operating as a border IAB node. For example, the process shown in Fig. 4A may be executed before transmitting an RRCSetupComplete message in step S605 in Fig. 6 described later.

[0063] First, in S450, the mobile IAB node 306 determines whether it can operate as a border IAB node. Whether it can operate as a border IAB node may be determined based on any criteria. For example, the criteria may include that the location of the mobile IAB node 306 is within a location range in which it can operate as a border IAB node.

[0064] If the node can operate as a boundary IAB node, in step S451, the mobile IAB node 306 includes, in the RRC message, predetermined information indicating that the node can operate as a boundary IAB node. The predetermined information is information indicating whether the node can operate as a boundary IAB node. On the other hand, if the node cannot operate as a boundary IAB node, in step S452, the mobile IAB node 306 includes, in the RRC message, predetermined information indicating that the node cannot operate as a boundary IAB node. Note that in another embodiment, if the node cannot operate as a boundary IAB node, in step S452, the mobile IAB node 306 may not include the predetermined information itself in the RRC message.

[0065] According to the process shown in FIG. 4A, the IAB donor 302 side receiving the RRC message can know whether the mobile IAB node 306 can operate as a border IAB node based on predetermined information.

[0066] FIG. 5 is a schematic flow chart showing the process flow performed at the IAB donor 302 in relation to the process shown in FIG. 4A.

[0067] Note that this flowchart is described on the assumption that the IAB node 306 operating as a border IAB node is a mobile IAB node that is premised on movement.

[0068] First, in F501, the mobile IAB node 306 joins the network topology via the IAB node 304, and the associated processing shown in FIG. 6 is executed.

[0069] Here, an example sequence when the mobile IAB node 306 joins the 5G network is shown in Fig. 6. This sequence is an example of a general IAB node 5G network connection sequence according to the 3GPP standard defined in 3GPP TR38.401.

[0070] First, the mobile IAB node 306 sends an RRCSetupRequest message to the IAB node 304 at S601.

[0071] When the IAB node 304 receives the message, if the IAB node 304 wants the sending mobile IAB node 306 to join the 5G network, it sends an initial UL RRC message to the IAB donor 302 at S602.

[0072] When the IAB donor 302 receives this message, it sends a DL RRC message (S603) to the IAB node 304, and the IAB node 304 sends an RRCSetup message (S604) to the mobile IAB node 306.

[0073] In response to this, the mobile IAB node 306 transmits an RRCSetupComplete message to the IAB node 304 in S605. Then, the IAB node 304 transmits a UL RRC message to the IAB donor 302 in S606 to relay the RRCSetupComplete message.

[0074] The IAB donor 302 sends a context setup request message to the IAB node 304 at S607 to establish a context for the mobile IAB node 306 that has connected to the IAB donor 302.

[0075] In response, the IAB node 304 sends a SecurityModeCommand message to the mobile IAB node 306 at S608.

[0076] After sending this message, the IAB node 304 asynchronously sends a context setup response message to the IAB donor 302 at S609.

[0077] In parallel with this, the mobile IAB node 306 sends a SecurityModeComplete message to the IAB node 304 at S610. The IAB node 304 relays the SecurityModeComplete message and sends a UL RRC message to the IAB donor 302 at S611.

[0078] Upon receiving this, the IAB donor 302 includes the RRCConfiguration message in a DL RRC message at S612 and transmits the message to the IAB node 304. The IAB node 304 relays the DL RRC message and transmits the RRCConfiguration message to the mobile IAB node 306 at S613.

[0079] The mobile IAB node 306 transmits an RRCConfigurationComplete message in response to the RRCConfiguration message to the IAB node 304 at S614. The IAB node 304 relays this and transmits a UL RRC message to the IAB donor 302 at S615.

[0080] Here, in this embodiment, the mobile IAB node 306 transmits the RRCSetupComplete message shown in S605 including the predetermined information as described above with reference to Fig. 4A. As described above, the predetermined information is information indicating whether the own node can operate as a boundary IAB node. In this embodiment, the predetermined information is an information field and a parameter indicating whether the own node can operate as a boundary IAB node.

[0081] The RRCSetupComplete message format is defined in 3GPP TS 38.331. In this case, predetermined information may be included in the RRCSetupComplete-IEs parameter or an extension parameter group of the RRCSetupComplete-IEs.

[0082] Furthermore, instead of or in addition to the RRCSetupComplete message, predetermined information may be included in an RRCSetupRequest message or an RRCReconfigurationComplete message.

[0083] Next, in F502, the IAB donor 302 determines whether the RRCSetupComplete message includes predetermined information. As described above, the RRCSetupRequest message may include predetermined information instead of or in addition to the RRCSetupComplete message. In this case, the IAB donor 302 may determine in F502 whether the RRCSetupRequest message includes predetermined information.

[0084] Regarding F502, more specifically, the IAB donor 302 determines whether the RRCSetupComplete message includes an information field indicating whether it is capable of operating as a border IAB node.

[0085] If it is determined in the determination process of F502 that the information field indicating whether or not the node can operate as a boundary IAB node is not included, it is determined that the series of processes for operating the node as a boundary IAB node shown in Fig. 4 is unnecessary. In other words, if the predetermined information indicates that the node cannot operate as a boundary IAB node, the process of F504 is not performed and the system returns to normal operation.

[0086] If it is determined in the determination process of F502 that the information field on whether or not the node can operate as a border IAB node is included, then in F503 it is determined whether or not the currently participating mobile IAB node 306 can operate as a border IAB node.

[0087] More specifically, a parameter included in the information field indicating whether or not the node can operate as a border IAB node is checked. The parameter may be a binary value, such as 1 for operable and 0 for inoperable. In another embodiment, the information field may be set only when the node is operable.

[0088] If it is determined in the determination process of F503 that the currently participating mobile IAB node 306 cannot operate as a boundary IAB node, it is determined that the series of processes for operating as a boundary IAB node shown in Fig. 4 is unnecessary. In other words, if the predetermined information indicates that it cannot operate as a boundary IAB node, the process of F504 is not performed and the system returns to normal operation.

[0089] Furthermore, if it is determined in the determination process of F503 that the currently participating mobile IAB node 306 can operate as a border IAB node, a series of processes for operating it as a border IAB node shown in Fig. 4 is required. That is, if the predetermined information indicates that it can operate as a border IAB node, the IAB donor 302 performs a series of processes for operating it as a border IAB node in F505 shown in Fig. 4.

[0090] In this way, according to this embodiment, an IAB node transmits to the IAB donor whether it can operate as a boundary IAB node, and the IAB donor 302 that receives the information can determine whether to perform the process shown in Fig. 4. This allows the process shown in Fig. 4 to be performed only on IAB nodes that can operate as boundary IAB nodes. As a result, it is possible to reduce the inconvenience (the increase in the system load described above) that may occur when all IAB nodes operate as boundary IAB nodes.

[0091] Next, another embodiment that may be realized instead of the first embodiment described above will be described. In the following, detailed description of the configuration that may be the same as the first embodiment described above will be omitted.

[0092] [Second embodiment] In the first embodiment described above, the IAB node transmits the predetermined information when it joins the network topology. Then, the IAB donor uses the predetermined information to determine whether or not to execute the series of processes shown in FIG. 4 for operating as a border IAB node. In contrast, the second embodiment utilizes the timing when the IAB node transmits surrounding environment information to the IAB donor, rather than the timing when the IAB node joins the network topology. Specifically, it is as follows.

[0093] As specified in 3GPP TS38.331, an IAB node periodically transmits collected surrounding environment information to an IAB donor in a MeasurementReport message.

[0094] This message is used by the IAB donor to configure the network topology. After receiving the Measurement Report message, the IAB donor sends an RRC Reconfiguration message to the IAB node that sent the message to reconfigure the network topology as necessary. This causes the IAB donor to be handed over.

[0095] The series of processes for operating as a border IAB node shown in Fig. 4 may be performed at such timing. In this case, predetermined information is included in the Measurement Report message and transmission is performed.

[0096] This allows the IAB donor to use the Measurement Report message to determine whether or not to carry out the series of processes shown in Figure 4 to operate as a border IAB node.

[0097] FIG. 7 shows a flow chart of the IAB donor 302 in this embodiment.

[0098] In the first embodiment, the IAB node 306 is a mobile IAB node that is assumed to move, but in this embodiment, it is described as an IAB node that does not move. However, it goes without saying that it may be a mobile IAB node that is assumed to move.

[0099] First, in F701, the IAB donor 302 receives a MeasurementReport message including predetermined information from the IAB node 306 via the IAB node 304. The MeasurementReport message format is defined in 3GPP TS38.331. In this case, the predetermined information can be included in a parameter in the MeasResults field in the MeasurementReport-IEs field.

[0100] Next, the IAB donor 302 performs a check of the current network topology in F702, and determines whether a change in the network topology of the IAB node 306 is necessary in F703.

[0101] If F703 determines that no change in the network topology is required, the system returns to normal operation.

[0102] Next, if it is determined in F703 that a change in the network topology is necessary, it is determined in F704 whether or not the IAB node 306 needs to operate as a boundary IAB node.

[0103] If it is determined in F704 that the IAB node 306 does not need to operate as a boundary IAB node, the system returns to normal operation. However, in this case, it may be determined that the IAB node 306 does not need to operate as a boundary IAB node, but a handover to another node is necessary. In other words, a handover process of the IAB node (not shown) may be executed.

[0104] If it is determined in F704 that it is necessary to operate as a border IAB node, it is determined in F705 whether or not predetermined information is included in the Measurement Report message being received.

[0105] More specifically, it is determined whether an information field indicating whether or not the node can operate as a border IAB node is included.

[0106] If it is determined in the determination process of F705 that the information field indicating whether or not the node can operate as a boundary IAB node is not included, it is determined that the series of processes for operating as a boundary IAB node shown in Fig. 4 is unnecessary. In this case, the process of F707 is not performed and the system returns to normal operation.

[0107] Also, if it is determined in the determination process of F705 that the information field on whether or not the node can operate as a boundary IAB node is included, then in F706 it is determined whether or not the IAB node can operate as a boundary IAB node.

[0108] More specifically, a parameter check is performed on the information field to determine whether the node can operate as a border IAB node.

[0109] If the judgment process of F706 determines that the IAB node cannot operate as a border IAB node, it is determined that the series of processes shown in Figure 4 for operating as a border IAB node is unnecessary, and the system returns to normal operation without performing the process of F707.

[0110] Furthermore, if it is determined in the judgment process of F706 that the IAB node can operate as a boundary IAB node, a series of processes shown in FIG. 4 are required to operate the IAB node as a boundary IAB node, and therefore the processes are carried out in F708.

[0111] The second embodiment as described above also provides the same effects as the first embodiment described above.

[0112] [Third embodiment] In the first and second embodiments described above, we have explained the transmission means for transmitting specified information and the decision timing for determining whether or not to perform a series of processes for the IAB donor to operate as a border IAB node as shown in Figure 4.

[0113] Here, the transmission means for transmitting the predetermined information (information on whether the IAB node can operate as a border IAB node) mainly uses an RRC message. However, the predetermined information may be included in the broadcast information of the IAB node such as a beacon and transmitted.

[0114] The broadcast information includes SSB, MIB, SIB, etc., and the information transmitted by these may include predetermined information (information on whether the source IAB node can operate as a border IAB node or not). Note that SSB is an abbreviation for Synchronization Signal Block. MIB is an abbreviation for Master Information Block. SIB is an abbreviation for System Information Block.

[0115] In particular, for the SIB, various information formats such as surrounding cell information, idle information, and side link related information are defined as specified in 3GPP TS38.331. It is also possible to create a new format for defining specific information within these definitions and send it as a new SIB.

[0116] Also, a field indicating predetermined information may be added to an existing information definition format.

[0117] Although each embodiment has been described above in detail, the present invention is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. In addition, it is also possible to combine all or a plurality of the components of the above-described embodiments.

[0118] For example, in the above-described embodiment, a determination is made as to whether or not to carry out a series of processes for the IAB donor to operate as a border IAB node, as shown in Figures 5 and 7. At this time, if it is determined in the determination processes of F502 and F705 that the predetermined information (information field indicating whether or not the node can operate as a border IAB node) is not included, the system returns to normal operation. In other words, as shown in F504 and F707, the connection process as a border IAB node is not carried out.

[0119] On the other hand, if the information transmitted from the IAB node includes information (another example of specified information) indicating whether or not the IAB donor will perform a series of processes to operate as a border IAB node, the system operation may be to perform connection processing as a border IAB node.

[0120] In this case, if it is determined in the judgment processes of F502 and F705 that the information field indicating whether or not the node can operate as a boundary IAB node is not included, a series of processes may be performed in F505 and F708 to operate the node as a boundary IAB node.

[0121] In addition, as a flowchart of the process for determining whether or not to perform a series of processes for an IAB donor to operate as a border IAB node, a mobile IAB node has been exemplified in the first embodiment, and an IAB node that does not move has been exemplified in the second embodiment. However, the determination process shown in Fig. 4 and Fig. 7 may be changed in the determination order or an additional determination process may be performed. For example, the process shown in F704 for determining whether the source IAB node needs to operate as a border IAB node may be performed as a pre-processing step of F502.

[0122] In the third embodiment, a method of including predetermined information in the broadcast information of the IAB node such as a beacon and transmitting the same is exemplified as a transmission means other than the RRC message. However, as another method, the information may be transmitted in a BAP (Backhaul Adaptation Protocol) message. The BAP message specification is defined in 3GPP TS38.340. In this case, the predetermined information (information field and parameters indicating whether the source IAB node can operate as a border IAB node) may be included in a data PDU (Protocol Data Unit) and a control PDU and transmitted.

[0123] In addition, the following supplementary notes are disclosed regarding the above embodiment.

[0124] (Appendix 1) A determination means for determining whether a node functioning as an IAB node forming one IAB (Integrated Access and Backhaul) network can operate as a border IAB node, which is an IAB node connected to both the one IAB network and another IAB network; A communication device comprising: a transmitting means for transmitting a communication message according to a result of the determination by said determining means. (Appendix 2) The communication device according to claim 1, wherein the communication message includes predetermined information indicating whether the node is capable of operating as the border IAB node. (Appendix 3) The communication device according to claim 2, wherein the specified information includes a parameter value representing the determination result. (Appendix 4) A communication device according to any one of Supplementary Notes 1 to 3, characterized in that it is movable as a mobile IAB node. (Appendix 5) A communication device that functions as an IAB donor that forms an IAB network, A receiving means for receiving a communication message from another communication device functioning as an IAB node; and a determination means for determining, based on the communication message, whether the other communication device is capable of operating as a border IAB node, which is an IAB node that connects to both the one IAB network and another IAB network. (Appendix 6) The communication device described in Appendix 5, wherein the determination means determines whether the other communication device is capable of operating as a border IAB node based on whether or not the communication message includes specified information. (Appendix 7) The communication device described in Appendix 6, wherein the determination means, when the communication message includes the specified information, determines whether the other communication device is capable of operating as a border IAB node based on the specified information. (Appendix 8) The communication device according to claim 6 or 7, wherein the specified information includes a parameter value indicating whether the other communication device is capable of operating as a border IAB node. (Appendix 9) The communication device according to any one of appendices 1 to 8, wherein the communication message is a Radio Resource Control (RRC) message, a Backhaul Adaptation Protocol (BAP) message, or a Measurement Report message. (Appendix 10) The communication message is an RRC message, 10. The communication device according to any one of Supplementary Notes 1 to 9, wherein the RRC message is an RRC SetupComplete message or a Measurement Report message. [Explanation of symbols]

[0125] 102 Control unit (judgment means, determination means) 103 Storage section 104 Wireless communication unit (transmitting means, receiving means) 105 Communication antenna control section 202 Signal transmission unit 203 Signal receiving unit 204 Data storage unit 205 Connection control section 206 RRC message detection unit 207 RRC message generator 208 Communication Control Unit 301 Core Network 302 IAB Donors 303 IAB Donors 304 IAB Node 306 IAB node (border IAB node) 310 IAB Nodes

Claims

1. A communication device, A determination means for determining whether the communication device can function as an IAB node forming one IAB (Integrated Access and Backhaul) network, and as a boundary IAB node forming one IAB network and another IAB network, A transmission means that transmits a communication message corresponding to the determination result of the determination means, A communication device characterized by having the following.

2. The communication device according to claim 1, characterized in that the communication message includes predetermined information indicating whether or not the communication device is capable of operating as the boundary IAB node.

3. The communication device according to claim 2, characterized in that the predetermined information includes the value of a parameter representing the determination result.

4. The communication device according to claim 1, characterized in that the communication device is a mobile communication device that can be moved as a mobile IAB node.

5. A control method that provides the functionality of an IAB donor forming a single IAB (Integrated Access and Backhaul) network, A receiving process that receives communication messages from other communication devices that function as IAB nodes, A determination step of determining whether the other communication device can operate as a boundary IAB node, which is an IAB node connected to both the first IAB network and the other IAB network, based on the aforementioned communication message. A control method characterized by having the following features.

6. The control method according to claim 5, characterized in that the determination step determines whether the other communication device can operate as a boundary IAB node based on whether or not predetermined information is included in the communication message.

7. The control method according to claim 6, characterized in that, in the determination step, if the communication message contains the predetermined information, it is determined whether the other communication device can operate as a boundary IAB node based on the predetermined information.

8. The control method according to claim 7, characterized in that the predetermined information includes a parameter value indicating whether or not the other communication device can operate as a boundary IAB node.

9. The control method according to claim 5, characterized in that the communication message is an RRC (Radio Resource Control) message, a BAP (Backhaul Adaptation Protocol) message, or a Measurement Report message.

10. The aforementioned communication message is an RRC message, The control method according to claim 5, characterized in that the RRC message is an RRC SetupComplete message or a MeasurementReport message.

11. A communication device that functions as an IAB donor forming an IAB (Integrated Access and Backhaul) network, A receiving means for receiving communication messages from other communication devices that function as IAB nodes, A determination means for determining whether the other communication device can operate as a boundary IAB node, which is an IAB node connected to both the first IAB network and the other IAB network, based on the aforementioned communication message. A communication device characterized by having the following features.

12. On the computer, A provision process that provides the function of an IAB donor that forms a single IAB (Integrated Access and Backhaul) network, A receiving process that receives communication messages from other communication devices that function as IAB nodes, A determination step of determining whether the other communication device can operate as a boundary IAB node, which is an IAB node connected to both the first IAB network and the other IAB network, based on the aforementioned communication message. A program to execute.

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