Communication control device, method for controlling a communication device, and program

Abstract

To provide communication in a slice requested by UE when requirements requested for communication in the slice cannot be met in an IAB (Integrated Access and Backhaul) network.SOLUTION: A communication control device of an IAB (Integrated Access and Backhaul) network detects that a first relay node that communicates with a base station of the network via a first communication path no longer satisfies requirements requested for communication in a predetermined slice, and according to the detection result, gives instruction on a connection to a second relay node that is located on a second communication path satisfying the requirements requested for communication in the predetermined slice and connectable from the first relay node.SELECTED DRAWING: Figure 4

Description

Technical Field

[0005] , , ,

[0001] The present invention relates to a communication control device, a control method for a communication device, and a program.

Background Art

[0002] In the Third Generation Partnership Project (3GPP (registered trademark)), the standardization of IAB (Integrated Access and Backhaul) as a communication technology for backhaul is progressing. The IAB technology is a technology that simultaneously uses millimeter-wave wireless communication such as the 28 GHz band used for access communication between a base station and a user equipment (UE: User Equipment) as backhaul communication (Patent Document 1). <​​​​​​​​​​​​​​​​​​​​​​​​​In this context, there is ongoing consideration of introducing a concept called network slicing, which virtually provides network slices (hereinafter referred to as slices) on a common network to meet the requirements of multiple different services in next-generation public networks. The types of slices defined are high-speed, high-capacity (eMBB), low-latency (URLLC), and simultaneous multiplexing (mMTC). eMBB stands for enhanced Mobile Broadband. URLLC stands for Ultra-Reliable and Low Latency Communication, and mMTC stands for massive Machine Type Communication. For example, a mechanism is being considered in which a UE requests a predetermined network slice, and the CN (Core Network) beyond the base station responds, allowing communication to take place using the requested network.

[0006] In an IAB network, changes in the processing load or communication environment of upstream connected IAB donors or IAB nodes can cause an IAB node that previously met the communication requirements for a slice to become unable to provide communication that meets those requirements. In such cases, the UE (User Environment) is unable to continue communication for that slice.

[0007] This invention has been made in view of the above-mentioned problems, and aims to provide communication in slices requested by the UE when the requirements for communication in a slice cannot be met in an IAB (Integrated Access and Backhaul) network. [Means for solving the problem]

[0008] To solve the above problems, the communication control device according to the present invention is A communication control device for an IAB (Integrated Access and Backhaul) network, A detection means for detecting that a first relay node communicating with a base station of the network via a first communication path no longer meets the requirements for communication in a predetermined slice, An instruction means that, in accordance with the detection result of the detection means, instructs a connection to a second relay node located on a second communication path that satisfies the requirements for communication in the predetermined slice and is connectable from the first relay node, Equipped with 、 When the detection means detects that the first communication path no longer meets the requirements for communication in multiple slices, the instruction means prioritizes slices with a large number of user devices requesting the slice and instructs a connection to the second relay node that meets the requirements for communication in that slice. [Effects of the Invention]

[0009] According to the present invention, in an IAB (Integrated Access and Backhaul) network, it is possible to provide communication in a slice as requested by the UE when the requirements for communication in that slice can no longer be met. [Brief explanation of the drawing]

[0010] [Figure 1] A diagram showing an example of a wireless communication system. [Figure 2] Hardware Function Block Diagram of Communication Device [Figure 3] Software Functional Block Diagram of Communication Device [Figure 4] A flowchart illustrating the method for determining a new connection destination according to Embodiment 1. [Figure 5] An example of a connection candidate list in IAB node 105 according to Embodiment 1 [Figure 6] (A) and (B) are examples of NSSAI lists for IAB donor 101 and each IAB node 102-105 according to Embodiment 1. [Figure 7] Sequence diagram showing the establishment of a multipath connection according to Embodiment 1 [Figure 8] Diagram showing the topology after connecting the new communication path according to Embodiment 1. [Figure 9]Flowchart of New Communication Path Determination in IAB Donor According to Embodiment 2 [Figure 10] An Example of Connection Candidate List in IAB104 According to Embodiment 2 [Figure 11] An Example of NSSAI Lists of IAB Donor 101 and Each IAB Node 102 - 105 According to Embodiment 2 [Figure 12] Diagram Showing Topology after New Communication Path Connection According to Embodiment 2

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential for the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0012] In backhaul communication using IAB technology, a relay device (relay node) called an IAB node relays communication from an IAB donor corresponding to a conventional base station by millimeter - wave communication. Further, the IAB node can form a communication link with a plurality of other IAB nodes and form a network starting from the IAB donor, thereby expanding the area.

[0013] In IAB technology, the IAB donor, IAB nodes, and between IAB nodes are controlled via the BAP (Backhaul Adaptation Protocol). The BAP is defined as a protocol for routing data between the IAB donor and IAB nodes. Also, in backhaul communication using IAB technology, in case the wireless communication situation between the IAB donor and IAB nodes deteriorates, it is being considered to restore and improve the communication situation by switching the communication path or forming multiple communication paths (hereinafter, multi-path connection). For example, studies are underway on a mechanism where the base station notifies the network slices it provides, and the UE selects according to the purpose, or the UE requests a network slice and the IAB donor responds for use.

[0014] Here, when the IAB donor provides a slice to the UE, requirements (slice requirements) are defined for communication in a predetermined slice. The slice requirements include, for example, communication speed (throughput), packet loss rate, and round-trip delay, and there are slice requirements with different parameters according to the type of slice. In such a case, although the IAB donor initially satisfied the slice requirements when providing communication in the slice to the UE, there may be a case where it becomes unable to satisfy the slice requirements due to a communication link failure or a change in the processing load of the IAB node. In such a case, the UE becomes unable to satisfy the requirements required for communication in the slice.

[0015] Therefore, when the communication control device according to this embodiment detects that the communication in a predetermined communication path provided to a predetermined UE fails to meet the requirements, it instructs the relay node on the predetermined communication path to connect to a communication path that meets the requirements. <0,

[0016] [Embodiment 1] Figure 1 shows an example of a wireless communication system in the present invention. The wireless communication system 100 shown in Figure 1 includes an IAB donor 101 and IAB nodes 102-105 (hereinafter sometimes referred to simply as IAB nodes) that provide a connection to CN130. The wireless communication system 100 is a network (IAB network) that communicates using BAP (Backhaul Adaptation Protocol). The IAB donor 101 provides a connection to CN130 via a backhaul link with the IAB nodes. The IAB nodes provide a connection to the IAB donor 101 to the UE via an access link. In the wireless communication system 100, NR (New Radio) communication is used in both the backhaul link and the access link within the network. The IAB donor 101 forms an IAB network (NR backhaul network) that includes the IAB nodes. Here, CN stands for Core Network and is responsible for various processes such as authentication of user devices UE110-118 (hereinafter sometimes referred to simply as UE) and registration of network slices (slice) usage.

[0017] IAB donor 101 is an example of a base station device that centrally controls each IAB node and forms the area covered by its station. In this embodiment, the IAB donor 101 is described as a communication control device that performs the communication control described above. However, the functions of the communication control device may be provided in a device other than the IAB node, the network node of the core network, or the IAB node and IAB donor 101 within the wireless communication system 100.

[0018] IAB donor 101 determines and assigns the types of network slices that each IAB node can support. IAB donor 101 also manages the slice information supported by each IAB node as an NSSAI list. Here, NSSAI stands for Network Slice Selection Assistance Information. Furthermore, if there is a change in the slices supported by IAB nodes 102-105, IAB donor 101 is notified via a BAP control message.

[0019] IAB donor 101 and IAB node function as communication devices, as described below, and in the following description, the communication device will be assumed to be either IAB donor 101 or IAB node.

[0020] A BAP control message is defined as a message exchanged in accordance with the format of a BAP control PDU (Protocol Data Unit). Control information may be notified using the PDU type field, or other Reserved fields may be used.

[0021] In the wireless communication system 100, when each UE receives service from CN130, packets from CN130 are transmitted downlink to each UE via IAB donor 101. Similarly, on the uplink, packets from each UE are transmitted to CN130 via IAB donor 101.

[0022] Here, within the wireless communication system 100, packets conforming to the BAP data PDU (Protocol Data Unit) format (hereinafter sometimes referred to as BAP data packets) are transmitted as packets. For example, an IP (Internet Protocol) packet from CN130 destined for UE118 is converted into a BAP data packet at IAB donor 101 and forwarded into the IAB network 100. The forwarded BAP data packet is relayed by IAB nodes 102-105, converted back into an IP packet at IAB node 105, and delivered to the destination UE118. Similarly, an IP packet from UE118 is also converted into a BAP data packet at IAB node 105, converted back into an IP packet at IAB donor 101 via the IAB network 100, and forwarded to CN130.

[0023] UE110-119 (hereinafter sometimes referred to simply as UE) are assumed to be running applications that utilize the desired slice provided by each IAB node. As mentioned above, the types of slices are defined as high-speed, high-capacity (eMBB), low-latency (URLLC), and simultaneous multiplexing (mMTC). For example, UE118 is running an application that requests an MIoT slice, and UE119 is running an application that requests an eMBB.

[0024] Here, in the wireless communication system 100 shown in Figure 1, assume that the wireless quality deteriorates in the communication path between IAB node 104 and IAB node 105, resulting in a link failure. In this case, IAB node 105 will no longer meet the requirements for communication in the slice (slice requirements), and the application being executed by UE 119 may experience errors. In this embodiment, assume that the eMBB no longer meets the slice requirements. In this case, IAB node 105 detects that it no longer meets the eMBB slice requirements and notifies IAB donor 101 of this failure to meet the slice requirements (requirements not met) using a BAP control message. In one example, the IAB node may also notify IAB donor 101 of a change in NSSAI using a BAP control message. IAB node 105 may detect the failure to meet slice requirements when an eMBB slice request occurs from UE 119, or it may determine this itself based on the signal quality from IAB node 104, which is periodically measured by RRM. RRM stands for Radio Resource Management.

[0025] For example, failure to meet slicing requirements at IAB node 104 may be detected by an eMBB slicing request from UE119, or it may be determined locally by the signal quality from IAB node 102, which is periodically measured by RRM.

[0026] The following describes how IAB donor 101, acting as a communication control device, determines and notifies the destination for a new communication path in order to recover slices that have not met the slicing requirements at IAB node 105.

[0027] Figure 2 is a hardware block diagram of the communication device according to this embodiment. The communication device consists of hardware components: a control unit 201, a storage unit 202, a wireless communication unit 203, and an antenna control unit 204.

[0028] The control unit 201 controls the entire device by executing a control program stored in the memory unit 202. In one example, the control unit 201 includes a processor that loads the control program into memory and executes it. The memory unit 202 stores the control program executed by the control unit 201. The memory unit 202 of the IAB donor 101 also stores various information such as the cell ID, connected UE information, and routing information for IAB nodes 102 to 105.

[0029] The wireless communication unit 203 is a wireless communication unit for performing cellular network communication such as LTE (Long Term Evolution) and 5G (Fifth Generation Mobile Communication System) in accordance with 3GPP (registered trademark) standards. Furthermore, the wireless communication unit 203 can measure the communication status with each IAB node and UE according to RRM, and can notify IAB donor 101 and IAB nodes 102-105 via RRC messages. RRC stands for Radio Resource Control. RRC messages have functions such as connection establishment, admission control, RRC status management, and notification of surrounding cell information and access restrictions at IAB nodes 102-105 and UEs 110-119. In addition, communication status that can be measured by RRM, a function of RRC, can be obtained such as the reference signal reception power and reference signal reception quality of adjacent cells.

[0030] The antenna control unit 204 controls the antenna used for wireless communication performed by the wireless communication unit 203. Note that a single communication device may have multiple control units 201 through 204. Furthermore, the communication device may include components typically found in base station equipment, such as a wired communication unit.

[0031] Figure 3 is a software function block diagram of the communication device according to the present invention. The software function block is stored in the storage unit 202 and implemented by the control unit 201. The software function block consists of a transmitting / receiving unit 301, a storage unit 302, a connection control unit 303, a requirement non-fulfillment detection unit 304, a connection candidate identification unit 305, a slice management unit 306, and a communication path determination unit 307.

[0032] The transmitting / receiving unit 301 controls the wireless communication unit 203 via the control unit 201 and performs cellular network communication such as LTE and 5G in accordance with the 3GPP (registered trademark) standard between the IAB nodes 102-105 and UEs 110-119. The storage unit 302 controls and manages the storage unit 202 and stores programs executed by the control unit 201, such as the operating system of the communication device. The storage unit 302 stores and holds the network topology of the IAB network 100, routing information of the IAB nodes 102-105, and information related to UEs 110-119. The connection control unit 303 controls the antenna control unit 204 via the control unit 201 during wireless communication.

[0033] The requirement non-meeting detection unit 304 detects that an IAB node no longer meets the slice requirements (requirement non-meeting). For example, the requirement non-meeting detection unit 304 can detect requirement non-meeting by comparing the NSSAI list received from the IAB node with the NSSAI list managed by the slice management unit 306 and observing the change in the slice types included in the list. Alternatively, if a slice request for a predetermined slice is received again from a UE that has already been assigned to a predetermined slice, the requirement non-meeting can be detected at the IAB node to which the UE is connected. Upon detecting requirement non-meeting, the requirement non-meeting detection unit 304 notifies the communication path determination unit 307 and updates the slice management unit 306.

[0034] The connection candidate identification unit 305 manages connection candidates that can be connected from each IAB node and identifies IAB nodes (connection candidate nodes) that can be connected from a given IAB node. In one example, the connection candidate identification unit 305 collects and manages a list of connection candidate IAB nodes from each IAB node. For example, IAB donor 101 sends a request signal for the connection candidate list to a given IAB node, and the IAB node that receives the request signal sends a response that includes the connection candidate list stored in the storage unit 302. The method by which IAB nodes create and update the connection candidate list will be described later with reference to Figure 5. In another example, the IAB node that receives the request signal may update the connection candidate list and send a response that includes the updated connection candidate list.

[0035] The slice management unit 306 stores and manages the NSSAI list supported by each IAB node, which is obtained from each IAB node via BAP control messages.

[0036] The communication path determination unit 307, upon notification from the requirement non-meeting detection unit 304, refers to the connection candidate list of the IAB node where the requirement non-meeting was detected, as well as the slice information of its own station and each IAB node, and determines a new communication path to a destination that can rescue the IAB node where the requirement non-meeting was detected. It also notifies the IAB node where the requirement non-meeting was detected of the determined new destination via an RRC control message. Here, an RRC control message is a message that conforms to the PDU format defined by RRC and is implemented using one of the fields that indicates the function provided by RRC. Notification to the IAB node via an RRC control message may also be notified using an NCL (Neighbor Cell List) containing only the new destination.

[0037] Here, we have described the functional blocks assuming a communication control device, but other configurations, excluding the requirement non-meeting detection unit 304, the connection candidate identification unit 305, and the communication path determination unit 307, are assumed to be similar for other communication devices.

[0038] Figure 4 is a flowchart showing the method for determining a new connection destination executed by the communication control device according to Embodiment 1. This flowchart can be started when the IAB donor 101, which operates as a communication control device, receives a BAP control message. This processing example describes the process when, in the network topology shown in Figure 1, the wireless quality deteriorates in the communication path between IAB node 104 and IAB node 105, resulting in a link failure, and consequently, IAB node 105 can no longer meet the requirements of eMBB.

[0039] In S400, the IAB donor 101 requirement non-meeting detection unit 304 detects, based on the received RRC control message, that the IAB node 105 no longer meets the slicing requirements. The requirement non-meeting detection unit 304 instructs the connection candidate identification unit 305 to identify a connection candidate node for the IAB node 105 that no longer meets the slicing requirements.

[0040] In S401, the connection candidate identification unit 305 identifies connection candidates by collecting a list of connection candidates via RRC control messages. In S401, the IAB donor 101 sends a request to the IAB node 105 to send the list of connection candidates, and the IAB node 105 responds to the request by sending a request response that includes the list of connection candidates. However, the connection candidate identification unit 305 may identify connection candidate nodes by obtaining the list of connection candidates stored in the storage unit 302, or it may send a request to an IAB node other than the IAB node 105 to send the list of connection candidates.

[0041] The processing in S402 through S411 is repeated for all IAB nodes (IAB nodes 102-103 in this example) included in the list of connection candidates for IAB node 105 that does not satisfy the slice.

[0042] In S403, the NSSAI list of candidate connection nodes n managed by the slice management unit 306 is referenced to determine whether candidate connection node n meets the eMBB slicing requirements. If the requirements are met (Yes in S403), S406 is executed; otherwise (No in S403), S405 is executed, and S403 is determined for the next candidate connection node n.

[0043] In S406, IAB node 105 is notified via an RRC control message that a multipath connection will be established at candidate node n. The RRC control message sent in S406 includes identification information for candidate node n. This allows IAB node 105, upon receiving the notification, to send a connection request to candidate node n. Here, it is assumed that candidate node n has established a communication path with IAB donor 101, and that this communication path satisfies the slice request. By sending a connection request to such candidate node n, IAB node 105 can connect to a communication path that satisfies the slice request.

[0044] In another example, S406 may notify candidate node n of an update to the communication path. For example, candidate node n may be instructed to update the communication path by sending the identification information of IAB node 105 associated with the communication path identifier to candidate node n.

[0045] Upon receiving notification of a multipath connection from IAB donor 101, IAB node 105 connects to the new destination IAB nodes 102-103 and receives the eMBB. Here, IAB node 105 may perform a reconnection operation in accordance with Cell ReSelection in the RRC protocol, but only for the subnet of a specific slice (eMBB).

[0046] In the example shown in Figure 4, it is assumed that IAB node 105 maintains its connection with IAB node 104, and that communication via MIot in UE 118 continues. In one example, IAB node 105 may disconnect its connection with IAB node 104 and connect to a new IAB node. In this case, in S406, IAB donor 101 may instruct IAB node 105 to switch the connection (handover) to IAB node 104. In other words, in S406, it is sufficient to instruct a connection to candidate node n that satisfies the slicing requirements, and whether or not IAB node 105 performs a multipath connection can be changed as appropriate.

[0047] For example, IAB donor 101 may instruct IAB node 105 to disconnect from IAB node 104 if the new destination IAB node 102 meets all the requirements for communication in the slice that IAB node 105 should support. In this case, IAB donor 101 may also instruct IAB node 105 to communicate in the slice that it should support via the communication path with IAB node 102.

[0048] In another example, IAB donor 101 may instruct the disconnection of the connection to the communication path previously established by IAB node 105 if the new destination IAB node 102 is located on a communication path already established by IAB node 105. For example, IAB node 105 is already communicating with IAB donor 101 via IAB nodes 102 and 104. If IAB node 102 is determined to be the new destination IAB node 102, the path IAB donor 101-IAB node 102-IAB node 104 will include the new communication path IAB donor 101-IAB node 102. In such a case, since the already established communication path also follows the same route as the new communication path, the new communication path must satisfy the slice requirements that IAB node 105 must support. In such cases, IAB donor 101 may also have IAB node 105 disconnect from IAB node 104 and switch to a new communication path to perform communication on the slice that IAB node 105 should support.

[0049] Figure 5 shows an example of a connection candidate list at IAB node 105 in Embodiment 1. The connection candidate list 500 is generated by each IAB node 102 to 105 from the RRM measurement results as neighboring cell information, and is collected and managed by the connection candidate identification unit 305 of the IAB donor 101 via RRC control messages. Alternatively, the IAB donor 101 may generate the list by collecting the RRM measurement results at each IAB node 102 to 105 via control messages of the RRC protocol and listing them, for example, in descending order of radio wave strength.

[0050] Alternatively, IAB donor 101 may collect and use NCLs as a list of connection candidates for each IAB node. In the connection candidate list 500 shown in Figure 5, among the IAB nodes that are connection candidates for IAB node 105, IAB node 102 has the strongest signal strength. In other words, it is determined that IAB node 102 is the node with the best communication quality among the connection candidate nodes.

[0051] Next, we will show an example of the NSSAI list for IAB donor 101 and each of the IAB nodes 102-105, and explain the process for determining whether or not IAB node 102 meets the slicing requirements in processing S403.

[0052] Figures 6(A) and 6(B) show an example of the NSSAI list for IAB donor 101 and each of the IAB nodes 102 to 105 in Embodiment 1.

[0053] Figure 6(A) shows the NSSAI list of IAB donor 101 and IAB node before a communication link failure occurred between IAB nodes in the wireless communication system 100 shown in Figure 1.

[0054] NSSAI list 600 is an example of slice correspondence information for IAB nodes that can be connected to from IAB donor 101. NSSAI lists 601 to 604 are examples of slice correspondence information for IAB nodes 102 to 105 managed by slice management unit 306. Here, 604 is the NSSAI list for IAB node 105 before detecting and updating the non-delivery of slices from IAB node 105.

[0055] The values ​​listed in NSSAI indicate the supported slice types, or SSTs (Slice Service Types): eMBB is "1", URLLC is "2", and MIoT is "3".

[0056] For example, as shown in NSSAI List 600, IAB donor 101 supports all slice types: eMBB, URLLC, and MIot. Also, as shown in NSSAI Lists 601-604, IAB nodes 102-105 support eMBB and MIot SST. Here, for a given IAB node to support a given slice type means that it can satisfy the requirements for communication in a given slice via a communication path between the given IAB node and IAB donor 101. For example, even if IAB node 102 receives a new eMBB slice request, it means that it has a communication path that satisfies the requirements for eMBB communication.

[0057] At this point, a communication link failure occurs between IAB nodes 104 and 105. IAB node 105 is affected by the communication link failure, making it unable to provide eMBB and supporting only MIot's SST. Therefore, in the updated NSSAI list of IAB node 105 shown in Figure 6(B), the NSSAI list of IAB node 105 only contains "3", which indicates MIoT. Here, 605 is the updated NSSAI list of IAB node 105 after detecting the slice failure from IAB node 105 in S400.

[0058] IAB node 102, a candidate for connection destination, supports eMBB as shown in 601. Therefore, IAB donor 101 selects IAB node 102 as the new connection destination for IAB node 105.

[0059] Figure 7 is a sequence diagram showing the multipath connection establishment performed by the wireless communication system 100 according to Embodiment 1. In Figure 7, the operation of establishing a multipath connection on a new communication path to IAB node 102 at IAB node 105 in order to recover an eMBB that has become unsupportable due to a communication link failure is explained.

[0060] In S700, communication for applications requesting eMBB takes place at UE119. Here, UE119 communicates with slice type eMBB via IAB node 105, which is directly connected to IAB node 104 and communicates with IAB donor 101 via IAB nodes 104 and 102. In S700, it is assumed that there is no communication link failure between IAB nodes 104 and 105, and that IAB node 105 meets the requirements for eMBB communication requested by UE119.

[0061] At this point, in S701, a failure occurs in the wireless link between IAB node 105 and IAB node 104, causing the packet loss rate on the wireless link to increase, and the requirements for throughput, packet loss rate, and round-trip delay required for communication to no longer be met. Here, we assume that the throughput required to support eMBB can no longer be secured. Then, in S702, UE119, having detected that the eMBB requirements can no longer be met due to the link failure, requests IAB node 105 to provide a slice that supports eMBB again via NSSAI.

[0062] S703 detects that IAB node 105 is no longer able to satisfy the eMBB in response to the NSSAI request from UE119.

[0063] In S704, IAB node 105 notifies IAB donor 101 of changes to the NSSAI it supports via a BAP control message. In S705, IAB donor 101, having received the BAP control message from the IAB node, detects that IAB node 105 can no longer fill the eMBB slices.

[0064] In S706, IAB donor 101 requests a list of connection candidates from IAB node 105 via an RRC control message. In S707, IAB node 105 sends the list of connection candidates generated from the RRM measurement results to IAB donor 101 via an RRC control message.

[0065] In S708, IAB donor 101 determines IAB node 102 as the new connection destination according to the flowchart in Figure 4, based on the list of connection candidates for IAB node 105 and the NSSAI list managed by slice management unit 306.

[0066] In S709 and S710, IAB donor 101 notifies IAB node 105 of the multipath connection with IAB node 102 via an RRC control message. Here, IAB node 102 may be specified as the connection destination by NCL as defined in the RRC protocol. In S711 and S712, IAB node 105 sends an RRC connection Reconfiguration message to form an RRC link with IAB node 102. In S713, a random access procedure is executed according to the RRC protocol, and an RRC link is established between IAB node 105 and IAB node 102. In S714 and S715, IAB node 102 sends an RRC connection Reconfiguration complete message to IAB node 105.

[0067] In S716 and S717, IAB node 105 notifies IAB donor 101 of the completion of the multipath connection via an RRC control message.

[0068] In S718, instead of an RRC Release message when switching communication paths, the IAB node 104 is notified of maintaining the connection via an RRC control message. Here, the message specified by RRC for communication path changes is used when establishing an RRC link, but other messages may be used as well. Furthermore, although each control message has been explained as being exchanged between BAP and RRC, this is not limited to this, and control may also be performed by message exchange at the application layer, for example.

[0069] As a result, as shown in S719, the IAB node 105 can support communication where the slice type requested by the UE119 is eMBB.

[0070] Figure 8 shows the topology of the IAB network after the establishment of a new communication path in Embodiment 1. In the wireless communication system 100, after the sequence in Figure 7 is executed, IAB node 105 establishes multipath connections to IAB node 102 via path 800 and to IAB node 104 via path 801. Path 800 to IAB node 102 enables IAB node 105 to provide communication to UE 119 in slices that support eMBB. IAB node 105 also maintains a communication path to IAB node 104, enabling it to provide communication in slices that support MIot as requested by UE 118.

[0071] As explained above, if a particular slice fails to meet the requirements at an IAB node, IAB donor 101 instructs the establishment of a new communication path to support that slice. This makes it possible to recover the slice that has failed to meet the requirements.

[0072] [Embodiment 2] In Embodiment 1, a method for determining a new connection destination when a link failure occurs between IAB node 105 and IAB node 104 in the wireless communication system 100 shown in Figure 1 was described.

[0073] Embodiment 2 describes a method for determining a new connection destination to recover the slice type eMBB requested by UE117 and UE119 in the event of a communication link failure between IAB node 104 and IAB node 102 as shown in Figure 1. Note that the same reference numerals are used for the same configurations, functions, and processes as in Embodiment 1, and their descriptions are omitted.

[0074] Figure 9 is a flowchart of the new communication path determination performed by the IAB donor 101 according to Embodiment 2. The process in Figure 9 may be started when the IAB donor 101 receives a BAP control message.

[0075] The S900 detects IAB nodes that do not meet the slicing requirements. In this example, IAB donor 101 receives BAP control messages from IAB nodes 104 and 105 indicating changes in supported NSSAI, and detects that IAB nodes 104 and 105 do not meet the slicing requirements.

[0076] In S901, the IAB donor 101 determines that a link failure has occurred between IAB node 104 and IAB node 102 based on the routing information stored in the memory unit 202 and the number of hops for IABs 104 and 105.

[0077] S902 collects a list of connection candidates for IAB node 104 and the downstream IAB node 105.

[0078] In the processing steps S903 through S908, IAB nodes that do not meet the slicing requirements are processed repeatedly, starting with those with the smallest number of hops to IAB donor 101.

[0079] In the processes from S904 to S906, the process is repeated for each candidate connection to a given IAB node. In S905, it is determined whether the candidate connection n of the IAB node satisfies the slicing requirements. If the requirements are met (Yes in S905), S910 is executed; otherwise, the process proceeds to S906.

[0080] In addition, in S905, IAB donor 101 may determine whether the slice requirements for communication in the slice requested by UEs 116-119 connected to IAB nodes 104 and 105 are met. In another example, IAB donor 101 may determine whether only the slice requirements for communication in the slice requested by UEs 116 and 117 connected to IAB node 104 are met. In this case, after instructing IAB node 104 to a new destination relay node, IAB donor 101 may also perform the processing from S903 to S908 for IAB node 105. That is, IAB nodes 104 and 105, which are detected as not meeting the slice requirements, may individually determine a new destination communication path.

[0081] In S906, if the process in S905 has been performed for all connection candidates, the process proceeds to S908; otherwise, the process proceeds to S907, and the process in S905 is performed for the next connection candidate. In S908, if the processes in S904 to S906 have been performed for all IAB nodes that do not meet the slicing requirements, the process shown in Figure 9 is terminated. In S908, if there are any IAB nodes that do not meet the slicing requirements and have not undergone the processes in S904 to S906, the process proceeds to S909, and the processes in S904 to S906 are performed for the IAB node 105 of the next connection candidate n.

[0082] The S910 sends an instruction to the IAB node via an RRC control message to perform a multipath connection at connection candidate n.

[0083] In this example, if there are no candidate connection nodes accessible from IAB node 104 that meet the slice requirements, the system determines which candidate connection nodes accessible from IAB node 105 meet the slice requirements. If it is determined that there is a candidate connection node accessible from IAB node 105 that meets the slice requirements, the system instructs IAB node 105 to connect to that IAB node. At this time, IAB node 104 may also be instructed to communicate via the newly established communication path of IAB node 105. This allows not only IAB node 104 to be supported, but also to recover the slices that IAB node 104 should support.

[0084] Figure 10 shows an example of a list of connection candidates for IAB node 104 in Embodiment 2. The list of connection candidates for IAB node 105 is the same as the list of connection candidates in Embodiment 1 shown in Figure 5.

[0085] Figure 11 shows the NSSAI list of IAB nodes after a communication link failure occurred between IAB nodes 102 and 104, and S900 detected and updated the list of IAB nodes after detecting undelivered slices from IAB nodes 104 and 105.

[0086] NSSAI lists 1100 and 1101 have been updated based on NSSAI change notifications from IAB nodes 104 and 105, and eMBB will no longer be supported.

[0087] In the connection candidate list 1000, among the connection candidates for IAB node 104, IAB donor 101 has the highest signal strength received by IAB node 104. Furthermore, IAB donor 101 can provide eMBB from S600. For this reason, in S905, IAB donor 101 is selected as the connection destination for IAB node 104. Here, the connection candidate list 1000 is limited to upstream connection nodes with fewer hops than IAB nodes 104 and 105, or IAB nodes that are not on the path to IAB donor 101 (i.e., neither upstream nor downstream connection nodes). As a result, IAB donor 101 instructs IAB node 104 to connect to IAB donor 101 in S910, and the process in Figure 9 is completed.

[0088] Figure 12 shows the topology of the IAB network after the new communication path is connected in Embodiment 2.

[0089] In the wireless communication system 100, the connection between IAB node 104 and IAB donor 101 and path 1200 is established according to the flowchart in Figure 9. This enables IAB node 104 to communicate on slices that support eMBB. Furthermore, because IAB node 104 can support slice type eMBB, IAB node 105 can also support eMBB. This resolves the issue of IAB node 105 not meeting slice requirements. This makes it possible to provide UE 117 and UE 119 with communication on slices that support eMBB.

[0090] In this embodiment, it has been explained that the failure to meet the slicing requirements of IAB node 105 can be resolved by establishing path 1200. However, if the failure to meet the slicing requirements of IAB node 105 cannot be resolved even after establishing path 1200, a BAP control message is sent again from IAB node 105 to IAB donor 101. In this case, IAB donor 101 instructs IAB node 105 again to establish a multipath connection that satisfies the slicing requirements.

[0091] [Other embodiments] Embodiments 1 and 2 described multipath connections. However, if an RLF (Radio Link Failure) is notified as a BAP control message rather than a decrease in communication quality, the communication path may be switched to a newly determined destination. The procedure for switching is the same as when performing a multipath connection, and an RRC Release message is sent to the original destination in S717.

[0092] Furthermore, if the IAB node 102, which has been determined as a new connection destination as in Embodiment 1, is an upstream connection node of the currently connected IAB node 104, the MIoT requested by UE118 is supported, and the communication path connection may be switched.

[0093] Furthermore, while embodiments 1 and 2 rescued a single slice at IAB nodes 102-105, if multiple slices fail to meet the requirements, the system may prioritize rescuing the slice with the largest number of requesting UEs. If the slice with the largest number of requesting UEs cannot be rescued, a new communication path is determined to rescue the next largest number of requesting UEs.

[0094] In this embodiment, as shown in Figure 5, the process of determining the destination IAB node based on the received signal strength of the candidate node was described. However, the destination IAB node may be determined based on other communication quality factors. For example, the destination IAB node may be determined based on parameters relating to the communication path between the candidate node and the IAB donor 101. The parameters may be at least one combination of the maximum communication capacity, the difference between the maximum communication capacity and the currently used communication capacity, the processing load of the candidate node, the available buffer capacity of the candidate node, and the processing load of the candidate node.

[0095] [Summary of Embodiments] At least some of the embodiments described above can be summarized as follows:

[0096] (Item 1) A communication control device for an IAB (Integrated Access and Backhaul) network, A detection means for detecting that a first relay node communicating with a base station of the network via a first communication path no longer meets the requirements for communication in a predetermined slice, An instruction means that, in accordance with the detection result of the detection means, instructs a connection to a second relay node located on a second communication path that satisfies the requirements for communication in the predetermined slice and is connectable from the first relay node, A communication control device characterized by comprising:

[0097] (Item 2) The communication control device according to item 1, characterized in that the instruction means identifies the second relay node from a relay node not included on the first communication path.

[0098] (Item 3) The system further includes a storage means for storing, in association, candidate connection nodes that can be connected from the first relay node, and the communication quality between the candidate connection nodes and the first relay node. The communication control device according to item 1 or 2, characterized in that, when the instruction means identifies a plurality of relay nodes that are connectable from the first relay node and satisfy the requirements for communication in the predetermined slice, it identifies a relay node with high communication quality with the first relay node as the second relay node.

[0099] (Item 4) The system further includes an acquisition means for acquiring a list of connection candidates indicating relay nodes that can be connected from the first relay node, The communication control device according to any one of items 1 to 3, characterized in that the instruction means identifies a relay node that can be connected from the first relay node based on the connection candidate list acquired by the acquisition means.

[0100] (Item 5) The aforementioned instruction means is If a second relay node located on a second communication path that satisfies the requirements for communication in the predetermined slice and is connectable from the first relay node cannot be identified, a fourth relay node is identified that is connectable from a third relay node communicating with the base station via the first relay node and satisfies the requirements for communication in the predetermined slice. The third relay node is instructed to connect to the fourth relay node. A communication control device according to any one of items 1 to 4, characterized by the above.

[0101] (Item 6) The communication control device according to any one of items 1 to 5, characterized in that the instruction means instructs the first relay node to disconnect the first communication path when the second communication path satisfies the requirements for communication in the slice to be supported by the first relay node.

[0102] (Item 7) The communication control device according to any one of items 1 to 6, characterized in that the instruction means instructs the first relay node to disconnect the first communication path when the second communication path includes the first communication path.

[0103] (Item 8) Each relay node in the network further has storage means for storing requirement satisfaction information indicating the requirements that can be met by communication in the slice supported by the relay node, A communication control device according to any one of items 1 to 7, characterized in that the detection means determines that the first communication path no longer satisfies the requirements required for communication in the predetermined slice when the requirement satisfaction information stored in the storage means indicates that the first relay node satisfies the requirements required for communication in the predetermined slice, and when it receives a slice request for the predetermined slice from a user device (UE) that is assigned to the predetermined slice and connected to the first relay node.

[0104] (Item 9) When the detection means detects that the first relay node no longer satisfies the requirements for communication in the predetermined slice, the network further includes acquisition means for acquiring requirement satisfaction information for each relay node in the network, which indicates the requirements that can be satisfied by communication in the slice supported by that relay node. A communication control device according to any one of items 1 to 8, characterized in that, based on the requirement satisfaction information acquired by the acquisition means, it identifies the relay node with the smallest number of hops to the base station among relay nodes that no longer satisfy the requirements required for communication in the predetermined slice, and determines a relay node that can be connected from the identified relay node and that satisfies the requirements to be satisfied for communication in the slice supported by that relay node.

[0105] (Item 10) The communication control device according to any one of items 1 to 9, characterized in that, when the detection means detects that the first communication path no longer satisfies the requirements for communication in multiple slices, the instruction means prioritizes slices with a large number of user devices requesting the slice and instructs a connection to the second relay node that satisfies the requirements for communication in that slice.

[0106] (Item 11) A communication control method performed by a communication control device of an IAB (Integrated Access and Backhaul) network, To detect that a first relay node communicating with a base station of the network via a first communication path no longer meets the requirements for communication in a predetermined slice, Depending on the detection result, instruct a connection to a second relay node located on a second communication path that satisfies the requirements for communication in the predetermined slice and is connectable from the first relay node, A communication control method characterized by including

[0107] (Item 12) A program that causes a computer to function as one of the means of a communication control device described in any one of items 1 through 10.

[0108] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0109] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of symbols]

[0110] 100 Wireless communication system, 101 IAB donor, 102-105 IAB node, 110-119 UE, 201 Control unit, 202 Storage unit, 203 Wireless communication unit, 204 Antenna control unit, 301 Transceiver unit, 302 Storage unit, 303 Connection control unit, 304 Requirement failure detection unit, 305 Connection candidate identification unit, 306 Slice management unit, 307 Communication path determination unit

Claims

1. A communication control device for an IAB (Integrated Access and Backhaul) network, A detection means for detecting that a first relay node communicating with a base station of the network via a first communication path no longer meets the requirements for communication in a predetermined slice, An instruction means that, in accordance with the detection result of the detection means, instructs a connection to a second relay node located on a second communication path that satisfies the requirements for communication in the predetermined slice and is connectable from the first relay node, Equipped with, A communication control device characterized in that, when the detection means detects that the first communication path no longer satisfies the requirements for communication in multiple slices, the instruction means prioritizes slices with a large number of user devices requesting the slice and instructs a connection to the second relay node that satisfies the requirements for communication in that slice.

2. The communication control device according to claim 1, characterized in that the instruction means identifies the second relay node from a relay node not included on the first communication path.

3. The system further includes a storage means for storing, in association, candidate connection nodes that can be connected from the first relay node, and the communication quality between the candidate connection nodes and the first relay node. The communication control device according to claim 1, characterized in that, when the instruction means identifies a plurality of relay nodes that are connectable from the first relay node and satisfy the requirements for communication in the predetermined slice, it identifies a relay node with high communication quality with the first relay node as the second relay node.

4. The system further includes an acquisition means for acquiring a list of connection candidates indicating relay nodes that can be connected from the first relay node, The communication control device according to claim 1, characterized in that the instruction means identifies a relay node that can be connected from the first relay node based on the connection candidate list acquired by the acquisition means.

5. The aforementioned instruction means is If a second relay node located on a second communication path that satisfies the requirements for communication in the predetermined slice and is connectable from the first relay node cannot be identified, a fourth relay node is identified that is connectable from a third relay node communicating with the base station via the first relay node and satisfies the requirements for communication in the predetermined slice. The third relay node is instructed to connect to the fourth relay node. The communication control device according to claim 1.

6. The communication control device according to claim 1, wherein the instruction means instructs the first relay node to disconnect the first communication path when the second communication path satisfies the requirements for communication in the slice to be supported by the first relay node.

7. The communication control device according to claim 1, characterized in that the instruction means instructs the first relay node to disconnect the first communication path when the second communication path includes the first communication path.

8. Each relay node in the network further has storage means for storing requirement satisfaction information indicating the requirements that can be met by communication in the slice supported by the relay node, The communication control device according to claim 1, characterized in that the detection means determines that the first communication path no longer satisfies the requirements required for communication in the predetermined slice when the requirement satisfaction information stored in the storage means indicates that the first relay node satisfies the requirements required for communication in the predetermined slice, and when it receives a slice request for the predetermined slice from a user device (UE) that is assigned to the predetermined slice and connected to the first relay node.

9. When the detection means detects that the first relay node no longer satisfies the requirements for communication in the predetermined slice, the network further includes acquisition means for acquiring requirement satisfaction information for each relay node in the network, which indicates the requirements that can be satisfied by communication in the slice supported by that relay node. The communication control device according to claim 1, characterized in that, based on the requirement satisfaction information obtained by the acquisition means, it identifies the relay node with the smallest number of hops to the base station among relay nodes that no longer satisfy the requirements required for communication in the predetermined slice, and determines a relay node that is connectable from the identified relay node and satisfies the requirements that must be satisfied for communication in the slice supported by that relay node.

10. A communication control method performed by a communication control device of an IAB (Integrated Access and Backhaul) network, To detect that a first relay node communicating with a base station of the network via a first communication path no longer meets the requirements for communication in a predetermined slice, Depending on the detection result, instruct a connection to a second relay node located on a second communication path that satisfies the requirements for communication in the predetermined slice and is connectable from the first relay node, Includes, A communication control method characterized in that, when detecting that the first communication path no longer satisfies the requirements for communication in multiple slices, the method instructs that slices with a large number of user devices requesting the slice be prioritized and that the connection be made to the second relay node that satisfies the requirements for communication in that slice.

11. A program that causes a computer to function as one of the means of a communication control device according to any one of claims 1 to 9.

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