Optimization in integrated access and backhaul networks

Abstract

Embodiments of the present disclosure relate to supporting paging optimization in an integrated access and backhaul (IAB) network. The IAB node performs a migration from the first IAB donor to the second IAB donor. The IAB node sends a message to a network device, the message including a first set of identifiers associated with a connection between the IAB node and a first IAB donor, and a second set of identifiers associated with a connection between the IAB node and a second IAB donor. In this manner, the reliability of IAB communications may be improved.

Description

Technical Field

[0001] The exemplary embodiments of this disclosure generally relate to the telecommunications field, and more particularly to Integrated Access Backhaul (IAB) nodes, network devices, methods, apparatuses, and computer-readable storage media for optimizing IAB networks. Background Technology

[0002] The communication system may include one or more IAB nodes to enable rapid and cost-effective deployment. IAB nodes can use the same Uu air interface for access and backhaul, thereby creating a hierarchical radio multi-hop network between sites. These hops may terminate at an IAB donor connected to the core network (CN) via traditional backhaul. An IAB donor may include a Central Unit (CU) portion and a Distributed Unit (DU) portion. An IAB node may include a Mobile Terminal (MT) portion and a Distributed Unit (DU) portion; the MT portion can operate like a UE towards a parent IAB node or IAB donor, and the DU portion can operate like a base station towards the terminal equipment or mobile terminal of a child IAB node. On the access link, an IAB node can operate like a regular base station, providing an NR radio interface for user equipment (UEs) within its coverage area. The DU portion of an IAB node can provide one or more cells to serve UEs.

[0003] Due to potential failures on the backhaul (BH) connection or changes in IAB topology or IAB mobility, an IAB node may need to change its serving node, which can be located under (multiple) the same or different IAB donors. Summary of the Invention

[0004] Overall, the exemplary embodiments of this disclosure provide a solution for optimizing IAB networks, particularly for supporting paging optimization in IAB networks.

[0005] In a first aspect, an Integrated Access Backhaul (IAB) node is provided. The IAB node includes at least one processor and at least one memory storing instructions. When executed by the at least one processor, the instructions cause the IAB node to at least: perform a migration from a first IAB donor to a second IAB donor; and send a message to a network device, the message including: a first set of identifiers associated with a connection between the IAB node and the first IAB donor, and a second set of identifiers associated with a connection between the IAB node and the second IAB donor.

[0006] In a second aspect, a first network device is provided. The first network device includes: at least one processor; and at least one memory storing instructions. When executed by the at least one processor, the instructions cause the first network device to at least: obtain a first set of identifiers associated with a connection between an Integrated Access Backhaul (IAB) node and a first IAB donor, and a second set of identifiers associated with a connection between an IAB node and a second IAB donor; and send a message including the first set of identifiers and the second set of identifiers to a second network device.

[0007] In a third aspect, a second network device is provided. The second network device includes: at least one processor; and at least one memory storing instructions. When executed by the at least one processor, the instructions cause the second network device to at least: receive a message from an Integrated Access Backhaul (IAB) node or a first network device, the message including: a first set of identifiers associated with a connection between the IAB node and a first IAB donor, and a second set of identifiers associated with a connection between the IAB node and a second IAB donor; and, based on determining that context information of at least one terminal device includes the first set of identifiers, store the second set of identifiers in the context information of the at least one terminal device, wherein the at least one terminal device is in an idle state.

[0008] In a fourth aspect, a method is provided. The method includes: performing a migration from a first IAB donor to a second IAB donor at an Integrated Access Backhaul (IAB) node; and sending a message to a network device including: a first set of identifiers associated with the connection between the IAB node and the first IAB donor, and a second set of identifiers associated with the connection between the IAB node and the second IAB donor.

[0009] In a fifth aspect, a method is provided. The method includes: at a first network device, obtaining a first set of identifiers associated with a connection between an Integrated Access Backhaul (IAB) node and a first IAB donor, and a second set of identifiers associated with a connection between an IAB node and a second IAB donor; and sending a message including the first set of identifiers and the second set of identifiers to a second network device.

[0010] In a sixth aspect, a method is provided. The method includes: receiving a message at a second network device from an Integrated Access Backhaul (IAB) node or a first network device, the message including: a first set of identifiers associated with a connection between the IAB node and a first IAB donor, and a second set of identifiers associated with a connection between the IAB node and a second IAB donor; and storing the second set of identifiers in the context information of at least one terminal device, wherein the first set of identifiers is determined to be included in the context information of at least one terminal device, the at least one terminal device being in an idle state.

[0011] In a seventh aspect, an apparatus is provided. The apparatus includes: components for performing a migration from a first IAB donor to a second IAB donor at an Integrated Access Backhaul (IAB) node; and components for sending a message to a network device, the message including: a first set of identifiers associated with a connection between the IAB node and the first IAB donor, and a second set of identifiers associated with a connection between the IAB node and the second IAB donor.

[0012] In an eighth aspect, an apparatus is provided. The apparatus includes: means for obtaining at a first network device a first set of identifiers associated with a connection between an Integrated Access Backhaul (IAB) node and a first IAB donor, and a second set of identifiers associated with a connection between an IAB node and a second IAB donor; and means for sending a message including the first set of identifiers and the second set of identifiers to a second network device.

[0013] In a ninth aspect, an apparatus is provided. The apparatus includes: components for receiving a message at a second network device from an Integrated Access Backhaul (IAB) node or a first network device, the message including: a first set of identifiers associated with a connection between an IAB node and a first IAB donor, and a second set of identifiers associated with a connection between an IAB node and a second IAB donor; and components for storing the second set of identifiers in the context information of at least one terminal device based on determining that the context information of at least one terminal device includes the first set of identifiers, the at least one terminal device being in an idle state.

[0014] In a tenth aspect, an apparatus is provided. The apparatus includes: an execution circuitry configured to perform a migration from a first IAB donor to a second IAB donor at an Integrated Access Backhaul (IAB) node; and a transmission circuitry configured to send a message to a network device, the message including: a first set of identifiers associated with a connection between the IAB node and the first IAB donor, and a second set of identifiers associated with a connection between the IAB node and the second IAB donor.

[0015] In an eleventh aspect, an apparatus is provided. The apparatus includes: an obtaining circuitry configured to obtain, at a first network device, a first set of identifiers associated with a connection between an Integrated Access Backhaul (IAB) node and a first IAB donor, and a second set of identifiers associated with a connection between an IAB node and a second IAB donor; and a transmitting circuitry configured to transmit a message including the first set of identifiers and the second set of identifiers to a second network device.

[0016] In an eleventh aspect, an apparatus is provided. The apparatus includes: a receiving circuitry configured to receive a message at a second network device from an Integrated Access Backhaul (IAB) node or a first network device, the message including: a first set of identifiers associated with a connection between the IAB node and a first IAB donor, and a second set of identifiers associated with a connection between the IAB node and a second IAB donor; and a storage circuitry configured to store the second set of identifiers in context information of at least one terminal device, wherein the at least one terminal device is in an idle state, based on determining that context information of at least one terminal device includes the first set of identifiers.

[0017] In a thirteenth aspect, a non-transitory computer-readable medium is provided, comprising program instructions for causing a device to perform at least the method according to any one of the fourth to sixth aspects described above.

[0018] In a fourteenth aspect, a computer program is provided, including instructions that, when executed by a device, cause the device to perform at least the method according to any one of the fourth to sixth aspects above.

[0019] It should be understood that the summary section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0020] Some embodiments will now be described with reference to the accompanying drawings, in which:

[0021] Figure 1A An example communication network in which embodiments of the present disclosure may be implemented is shown;

[0022] Figure 1B and 1C The recommended RAN nodes and recommended cells for paging IEs are shown respectively.

[0023] Figure 2 A flowchart of a communication process according to some example embodiments of this disclosure is shown;

[0024] Figure 3A flowchart of a communication process according to some other example embodiments of this disclosure is shown;

[0025] Figure 4A and 4B Examples of communication processes according to some exemplary embodiments of this disclosure are shown;

[0026] Figure 5 A flowchart is shown illustrating a method implemented at an IAB node according to some embodiments of this disclosure;

[0027] Figure 6 A flowchart is shown illustrating a method implemented at a first network device according to some embodiments of the present disclosure;

[0028] Figure 7 A flowchart is shown illustrating a method implemented at a second network device according to some other embodiments of the present disclosure;

[0029] Figure 8 A simplified block diagram of an apparatus suitable for implementing embodiments of the present disclosure is shown; and

[0030] Figure 9 A block diagram of an example computer-readable medium according to some embodiments of the present disclosure is shown.

[0031] In all the accompanying drawings, the same or similar reference numerals denote the same or similar elements. Detailed Implementation

[0032] The principles of this disclosure will now be described with reference to some exemplary embodiments. It should be understood that these embodiments are described for illustrative purposes only and to assist those skilled in the art in understanding and implementing this disclosure, and do not imply any limitation on the scope of this disclosure. The disclosure described herein can be implemented in various ways other than those described below.

[0033] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0034] References to "an embodiment," "embodiment," "example embodiment," etc., in this disclosure indicate that the described embodiments may include specific features, structures, or characteristics, but not every embodiment includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, it should be understood that, whether explicitly described or not, incorporating other embodiments to affect such feature, structure, or characteristic is within the knowledge of those skilled in the art.

[0035] It should be understood that although the terms “first” and “second”, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of the exemplary embodiments, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0036] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that, when used herein, the terms “comprising,” “including,” “having,” “having,” “including,” and / or “containing” specify the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements is connected by “and” or “or”, means at least any one element, or at least any two or more elements, or at least all elements.

[0037] As used in this application, the term "circuit system" may refer to one or more of the following: (a) Hardware circuit implementation only (such as implementation only in analog and / or digital circuit systems) and (b) A combination of hardware circuitry and software, such as (if applicable): (i) A combination of (multiple) analog and / or digital hardware circuits and software / firmware, and (ii) Any part of a hardware processor (including (multiple) digital signal processors), software, and (multiple) memories, which work together to enable a device (such as a mobile phone or server) to perform various functions and (c) (Multiple) hardware circuits and / or (multiple) processors (such as (multiple) microprocessors or a portion of (multiple) microprocessors) that require software (e.g., firmware) to operate, but may be absent when operation does not require software.

[0038] This definition of "circuit system" applies to all uses of the term in this application, including in any claim. As another example, as used in this application, the term "circuit system" also covers only hardware circuitry or a processor (or multiple processors) or portions of hardware circuitry or a processor and their accompanying software and / or firmware. For example, if applicable to a particular claim element, the term "circuit system" also covers baseband integrated circuits or processor integrated circuits for mobile devices or similar integrated circuits in servers, cellular network devices, or other computing or networking devices.

[0039] As used herein, the term "communication network" refers to a network that conforms to any suitable communication standard, such as Long Term Evolution (LTE), LTE-A Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), etc. Furthermore, communication between terminal devices and network devices in a communication network can be performed according to any suitable generation of communication protocol, including but not limited to first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G) communication protocols and / or any other protocols currently known or to be developed in the future. Embodiments of this disclosure can be applied to various communication systems. Given the rapid development of communications, there will certainly be future types of communication technologies and systems that this disclosure can utilize. This should not be construed as limiting the scope of this disclosure to the systems described above.

[0040] As used herein, the term "network device" refers to a node in a communication network through which terminal devices access the network and receive services. Depending on the terminology and technology applied, a network device can refer to a base station (BS) or access point (AP), such as a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), an NR NB (also known as a gNB), a gNB distributed unit (gNB-DU), a gNB central unit (gNB-CU), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), a relay, a low-power node (such as a femtosecond, picosecond), and so on.

[0041] The term "terminal device" refers to any terminal device capable of wireless communication. By way of example and not limitation, a terminal device may also be referred to as a communication device, user equipment (UE), subscriber station (SS), portable subscriber station, mobile station (MS), or access terminal (AT). Terminal devices may include, but are not limited to, mobile phones, cellular phones, smartphones, VoIP phones, wireless local loop phones, tablets, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal devices (such as digital cameras), gaming terminal devices, music storage and playback devices, in-vehicle wireless terminal devices, wireless endpoints, mobile stations, laptop embedded devices (LEEs), laptop-mounted devices (LMEs), USB dongles, smart devices, wireless client devices (CPEs), Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. In the following description, the terms “terminal equipment”, “communication equipment”, “terminal”, “user equipment”, and “UE” may be used interchangeably.

[0042] The exemplary embodiments of this disclosure pertain to radio access networks with wireless backhaul and access points. The backhaul can be multi-hop or mesh-like. A key application of this disclosure is for IAB communication within a 3GPP IAB network having terminal devices, IAB nodes, and IAB donor nodes. Hereinafter, embodiments of this disclosure will be described with reference to 3GPP IAB networks. It should be understood that embodiments of this disclosure can also be applied to any other network with wireless backhaul.

[0043] Figure 1A An example communication network 100, in which exemplary embodiments of this disclosure can be implemented, is shown. For example... Figure 1A As shown, the communication network 100 includes a core network (CN) 110, a first IAB donor 120-1 and a second IAB donor 120-2 (collectively referred to as "IAB donor 120" or individually as "IAB donor 120"), IAB nodes 130, and terminal devices 150. As used herein, the terms "IAB node," "IAB-node," and "IAB device" are used interchangeably. The terms "IAB donor node," "IAB donor," "IAB-donor," and "IAB donor device" are used interchangeably.

[0044] exist Figure 1AIn the example architecture, IAB donor 120 communicates with CN 110. IAB node 130 is connected to one of the IAB donors 120. Terminal device 150 accesses the communication network 100 via IAB node 130. In some embodiments, IAB node 130 may be directly connected to one of the IAB donors 120. Alternatively, IAB node 130 may be connected to one of the IAB donors 120 via one or more parent IAB nodes (not shown) linked on multiple wireless backhaul hops. IAB donor 120 may also serve terminal devices (not shown) directly connected to it.

[0045] CN 110 may include one or more core network elements that provide different network functions, such as Mobility Management Entity (MME), Network Slice Selection Function (NSSF), Unified Data Repository (UDM), Access and Mobility Management Function (AMF), Operations Management and Maintenance (OAM), Network Repository Function (NRF), Session Management Function (SMF), Policy Control Function (PCF), Network Exposure Function (NEF), etc. IAB donors can communicate with the core network elements in CN 110, such as one or more AMFs.

[0046] In example communication network 100, the CN interface terminates at IAB donor 120, thus relaying is a radio access network (RAN) function. This architecture utilizes a split gNB architecture for CU and DU, such that CU functionality resides at IAB donor 120, and DU functionality resides at either IAB donor 120 or IAB node 130. For connection establishment and communication with a parent node (which can be another IAB node or IAB donor), IAB node 130 hosts MT functions corresponding to UE operation or a portion of UE operation.

[0047] The first IAB donor 120-1 may include IAB donor CU 121-1 and IAB donor DU 122-1. The first IAB donor 120-1 may include multiple IAB donor DUs. It is understood that IAB donor CU 121-1 and IAB donor DU 122-1 may be implemented in the same device or different devices. IAB donor CU 121-1 may also include a CU-control plane (CU-CP) and one or more CU-user planes (CU-UP). It should be understood that CU-CP and CU-UP may be implemented in the same device or different devices. Similarly, the second IAB donor 120-2 may include IAB donor CU 121-2 and IAB donor DU 122-2. The second IAB donor 120-2 may include multiple IAB donor DUs. IAB donors CU 121-1 and 121-2 may be collectively referred to as "IAB donor CU 121" or individually as "IAB donor CU 121". IAB donors DU 122-1 and 122-2 may be collectively referred to as "IAB donor DU 122" or individually as "IAB donor DU 122". IAB donors CU 121-1 and CU 121-2 may communicate with each other via the Xn interface. It should be understood that the Xn interface is merely an example; any suitable communication interface may be used between the first IAB donor 120-1 and the second IAB donor 120-2.

[0048] IAB node 130 may include MT portion 131 (also referred to as "IAB-UE 131") and DU portion 132 (also referred to as "gNB-DU 132" or "IAB-DU 132"). The MT portion of the IAB node maintains connectivity with one or more upstream nodes (e.g., using dual connectivity). IAB node 130 may include one or more IAB-DUs.

[0049] A CU (e.g., IAB donor CU 121) can be a logical node that may include functions (e.g., gNB functions) such as user data delivery, mobility control, radio access network sharing, location, session management, etc., in addition to those functions assigned only to the DU. The CU terminates the Radio Resource Control (RRC) connection of the IAB-UE via the Uu interface. The CU can control the operation of the DU on the frontend (F1) interface, i.e., the CU terminates the F1 connection of the IAB-DU. A DU (e.g., IAB donor DU 122 or IAB-DU 132) is a logical node that may include a subset of functions (e.g., gNB functions). Terminating the RRC connection of the IAB-UE and terminating the F1 connection of a co-located IAB-DU can be done by different CUs. For example, during the IAB integration phase, the same CU may terminate both the RRC connection of the IAB-UE and the F1 connection of the co-located IAB-DU. The IAB then performs a partial migration and establishes an RRC connection using a different CU, while the F1 connection of the co-located IAB-DU still terminates with the previous CU.

[0050] Multiple backhaul radio link control (RLC) channels can be established between the IAB-UE 131 and the parent node's DU, with an adaptation layer, known as the Backhaul Adaptive Protocol (BAP), agreed upon on top of the RLC layer. The IAB-DU 132 connects to the IAB donor CU 121 using an F1 interface that supports IAB functionality. For example, when the IAB node 130 is connected to the first IAB donor 120-1, the IAB-DU 132 establishes an F1 connection 161 with the IAB donor CU 121-1; and when the IAB node 130 is connected to the second IAB donor 120-2, the IAB-DU 132 establishes an F1 interface / connection 162 with the IAB donor CU 121-2. The F1 interface / connection may include an F1-C interface / connection and an F1-U interface / connection, via which the IAB-DU connects to the IAB donor CU-CP and IAB donor CU-UP, respectively. IAB node 130 may also be connected to different IAB donors (e.g., IAB donor 120-3, not shown in the figure), and IAB-DU 132 may establish an F1 connection 161 with IAB donor CU 121-1, or IAB-DU 132 may establish an F1 connection 162 with IAB donor CU 121-2. In other words, terminating the RRC connection of IAB-UE-131 and terminating the F1 connection of IAB-DU132 may be with the same or different IAB donor CUs.

[0051] IAB nodes can support the NR Uu radio interface (referred to as the MT function) to connect to the parent IAB node or the IAB donor's DU, and connect to the gNB-CU on the IAB donor via Radio Resource Control (RRC) signaling. Similar to conventional user equipment, IAB nodes can use RRC signaling to supply radio link measurements of alternative uplink nodes to their current serving CU. IAB node migration can be performed. For example, handover is performed for the IAB-UE based on signal strength, signal quality, and other factors. Therefore, the IAB topology (such as...) Figure 1A The IAB topology shown may be non-static. As a result of migration, IAB node 130 may change its parent node from a source parent device (e.g., first IAB donor 120-1) to a target parent device after migration (e.g., second IAB donor 120-2). The IAB topology may change over time due to fluctuations in radio conditions and as IAB nodes are moved, added, or removed. Therefore, IAB node 130 may be configured with a new cell identifier. The cell identifier can be used by IAB node 130 as a RAN node to facilitate the residency and service utilization of terminal device 150 and / or other child IAB nodes.

[0052] For example, the cell identifier can be the Radio Cell Global Identifier (NR CGI). The NR CGI Information Element (IE) is associated with the gNB Identifier (ID) and can be used to globally identify NR cells. The gNB ID is also known as the Global NG-RAN Node ID. The NR CGI IE can include the Public Land Mobile Network (PLMN) Identifier IE and the NR Cell Identifier IE. The leftmost bit of the NR Cell Identifier IE corresponds to the gNB ID.

[0053] Each of IAB-DU 132 and IAB donor DU 122 is capable of providing one or more cells to serve terminal equipment and / or IAB-UE. For example, as Figure 1AAs shown, at T1, IAB node 130 can be connected to the first IAB donor 120-1, while IAB-EU 131 can be served by IAB donor DU 122-1. IAB-DU 132 can be configured with a cell identifier NR CGI #X / associated with it. NR CGI #X is used when IAB-DU 132 establishes an F1 connection with IAB donor CU 121-1. IAB-DU 132 broadcasts NR CGI #X through the Uu interface, and terminal device 150 and other sub-IAB nodes can access cell 141 provided by IAB-DU 132. At T2, IAB node 130 can disconnect from the first IAB donor 120-1 and be connected to the second IAB donor 120-2, and IAB-UE 131 can be served by IAB donor DU 122-2. IAB-DU 132 can be configured with a new cell identifier NR CGI #Y / ​​associated with it and used during F1 establishment with IAB donor CU 121-2. IAB-DU 132 broadcasts NR CGI #Y on the Uu interface, and terminal device 150 and other sub-IAB nodes can access cell 142 provided by IAB-DU 132.

[0054] It should be understood that Figure 1A The architecture of network 100 shown is described for illustrative purposes only and does not imply any limitations. Furthermore, it should be understood that... Figure 1A The number and connections of IAB donors, IAB nodes, and terminal devices shown are for illustrative purposes only and do not imply any limitation. Network 100 may include any suitable number of IAB donors, IAB nodes, terminal devices, and other devices suitable for implementing the exemplary embodiments of this disclosure. Although not shown, it should be understood that one or more additional devices may be deployed in network 100.

[0055] Communication in communication system 100 can be implemented according to any and more suitable communication protocols, including but not limited to cellular communication protocols such as first-generation (1G), second-generation (2G), third-generation (3G), fourth-generation (4G), and fifth-generation (5G), wireless local network communication protocols (such as IEEE 802.11), and / or any other protocols currently known or to be developed in the future. Furthermore, communication can utilize any suitable wireless communication technology, including but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM), Discrete Fourier Transform Spread Spectrum OFDM (DFT-s-OFDM), and / or any other technologies currently known or to be developed in the future.

[0056] Mobile IAB technology is a 3GPP Rel-18 work item (WI). As mobile IAB relay base stations, when installed on vehicles (such as high-speed rail, buses, or ships), mobile IAB nodes can provide high-quality real-time communication services to passenger users. The trajectory of a mobile IAB node can be predefined or dynamically random. For example, Figure 1A IAB node 130 can be a mobile IAB node, for example, installed on a vehicle, and can migrate from the first IAB donor to the second IAB donor 120-2 when the vehicle moves. During or before the migration, the terminal device on the vehicle can switch to an RRC idle state. After the migration, downlink data may need to be sent to the terminal device. Since the terminal device has switched to an RRC idle state, the terminal device needs to be paged.

[0057] The paging optimization process is defined in TS23.502. AMF and (R)AN can support additional paging optimizations to reduce signaling load and network resources used to successfully page the UE via one or more of the following methods:

[0058] - Implement specific paging strategies through AMF (e.g., N2 paging messages are sent to the (R)AN node that last served the UE).

[0059] - When transitioning to CM-IDLE state, the AMF considers the information provided by the (R)AN regarding recommended cells and NG-RAN nodes. The AMF considers the (R)AN node-related portion of this information to determine the (R)AN nodes to be paged, and provides information about the recommended cells to each of these (R)AN nodes within the N2 paging message;

[0060] - The paging attempt count information provided by the AMF during paging is considered via (R)AN.

[0061] The NGAP UE CONTEXT RELEASE COMPLETE message can be sent to the AMF to indicate that the release of the connection between the terminal equipment and the gNB has been completed. The NGAP UE CONTEXT RELEASE COMPLETE message includes information about the recommended cell and the RAN node used for paging the IE. The information about the recommended cell and the RAN node used for paging the IE provides details about the recommended cell and the NG-RAN node used for paging. Figure 1B and 1CThe information regarding recommended cells and RAN nodes used for paging IEs shows the recommended RAN nodes and recommended cells for paging IEs, respectively. The AMF can store the received information in the UE context of the terminal device and use it when it needs to send an NGAP paging message to the terminal device based on the UE context. The NGAP paging message includes auxiliary data for paging IEs, and also includes the recommended cell for paging IEs. For example, the AMF can send an NGAP paging message to the recommended RAN node and request the RAN node to perform paging in the recommended cell, thereby avoiding sending (multiple) NGAP paging messages to all RAN nodes and the RAN nodes paging the UE in all cells belonging to the UE's registration area. However, the paging optimization process does not work in mobile IAB networks.

[0062] As referenced above Figure 1A As described above, at T1, when IAB-DU 132 connects with the first IAB donor 120-1, IAB-DU 132 uses the identifier NR CGI #X, which is associated with the gNB ID of the first IAB donor 120-1. The on-board terminal device 150 can then transition to the RRC idle state. When the terminal device 150 transitions to the RRC idle state, the first IAB donor 120-1 can send a UE CONTEXT RELEASE COMPLETE message to the AMF in CN 110, indicating that the release of the connection between the terminal device 150 and the first IAB donor 120-1 has been completed. The UE CONTEXT RELEASE COMPLETE message may include a recommended cell NR CGI #X and a recommended RAN node ID for the first IAB donor 120-1, indicating that the last visited NG-RAN node was the first IAB donor 120-1. The AMF stores the received information in the UE context of the terminal device 150.

[0063] The first IAB donor 120-1 may also include unvisited NG-RAN nodes / cells.

[0064] At T2, IAB node 130 is fully migrated to the second IAB donor 120-2. The vehicle-mounted terminal equipment 150 can move with IAB node 130. When the full migration is performed, the IAB-DU needs to change the NR CGI to align with the target IAB donor. Therefore, IAB-DU 132 stops using NR CGI#X and uses a new NR CGI#Y associated with the gNB ID of the second IAB donor. For example, IAB-DU 132 can initiate an F1 removal procedure to deactivate cell 141 or a gNB-DU configuration update procedure to delete cell 141. IAB-DU 132 uses the new NR CGI#Y when establishing an F1 connection using IAB donor CU 121-2.

[0065] At T3, downlink data may need to be sent to terminal device 150. Since terminal device 150 is in RRC idle state, it needs to be paged. For example, the AMF in CN 110 can initiate a network-triggered service request. In the network-triggered service request, the AMF can send a paging message to (multiple) eNBs or (multiple) gNBs to page terminal device 150. The AMF can check the stored UE context for terminal device 150. Since the recommended RAN node ID is the gNB ID of the first IAB donor 120-1, the AMF can send a paging message to the first IAB donor 120-1. Since the recommended cell is NR CGI#X, the paging message may include NR CGI#X.

[0066] However, since terminal device 150 has moved with IAB node 130 and IAB node 130 is now connected to the second IAB donor 120-2, the paging message should not be sent to the first IAB donor 120-1. The paging message should be sent to the second IAB donor 120-2. Furthermore, even if the first IAB donor 120-1 receives the paging message, it will be unable to send a paging message to IAB-DU 132 to perform paging, because IAB-DU 132 has been migrated to the second IAB donor 120-2, and NR CGI#X was deactivated after IAB node 130 was migrated to the second IAB donor 120-2. Even if the first IAB donor node 120-1 sends paging messages to all cells, paging may still fail because terminal device 150 has left. A solution is needed to support paging optimization when the terminal device moves with the IAB node and the IAB node has performed a full migration to a different IAB donor.

[0067] The Tracking Area Code (TAC) of the IAB-DU may or may not be changed depending on the configuration. In some embodiments of this disclosure, it is assumed that the TAC of the IAB-DU remains unchanged. The principles and embodiments of this disclosure will be described in detail below with reference to the accompanying drawings.

[0068] Now for reference Figure 2 , Figure 2 A communication process 200 according to an embodiment of the present disclosure is illustrated. For purposes of discussion, process 200 will be referred to... Figure 1A Described. Process 200 may involve, for example... Figure 1A The IAB node 130 shown. In some embodiments, such as Figure 1A As shown, process 200 may also involve a first IAB donor 120-1, a second IAB donor 120-2, or CN 110. Network device 210 may correspond to one of the first IAB donor 120-1, the second IAB donor 120-2, or CN 110. It should be understood that although process 200 has been shown... Figure 1A The process is described in the communication system 100, but it can also be applied to other communication scenarios.

[0069] In process 200, IAB node 130 performs a migration (202) from the first IAB donor 120-1 to the second IAB donor 120-2. IAB node 130 sends (204) message 206 to network device 210, which includes a first set of identifiers associated with the connection between IAB node 130 and the first IAB donor 120-1, and a second set of identifiers associated with the connection between IAB node 130 and the second IAB donor 120-2. Network device 210 receives (208) this message. In this way, when an IAB node migration occurs, both the original (or old) identifiers associated with the original connection (or old connection) and the new identifiers associated with the migrated connection can be reported to the network device, which can improve the reliability of IAB communication, especially for mobile IAB networks.

[0070] In some embodiments, the first identifier set may include identifiers of cells associated with the connection between IAB node 130 and first IAB donor 120-1, such as cell identifiers associated with the F1 connection between IAB-DU 132 and first IAB donor CU 121-1. In one example, it is a cell identifier provided to first IAB donor CU 121-1 by IAB-DU 132 during the F1 establishment process or the F1 gNB-DU configuration update process. Alternatively or additionally, the first identifier set may include identifiers of first IAB donor 120-1, such as the global NG-RAN node ID of first IAB donor 120-1. In other words, the first identifier set is a set of original identifiers that may correspond to the last visited RAN node and / or cell of the terminal device. In some embodiments, the second identifier set may include identifiers of cells associated with the connection between IAB node 130 and the second IAB donor 120-2, such as cell identifiers associated with the F1 connection between IAB-DU 132 and the first IAB donor CU 121-2. In one example, it is a cell identifier provided to the second IAB donor CU 121-2 by IAB-DU 132 during the F1 establishment process or the F1gNB-DU configuration update process. Alternatively or additionally, the second identifier set may include identifiers of the second IAB donor 120-2, such as the global NG-RAN node ID of the first IAB donor 120-2. In other words, the second identifier set is a set of new identifiers that may correspond to the RAN nodes and / or cells currently associated with the IAB node. In this way, when an IAB node migration occurs, the set of original identifiers and the set of new identifiers can be reported, thereby facilitating the updating of recommended RAN nodes and / or cells for the terminal device.

[0071] In some embodiments, network device 210 may be a first IAB donor 120-1. Alternatively, network device 210 may be a second IAB donor 120-2. Alternatively, network device 210 may be an AMF in CN 110. In some embodiments, the AMF may be associated with IAB node 130. In some embodiments, the message may be a request message for updating context information of a terminal device.

[0072] Figure 3 An example of a communication process 300 according to an embodiment of the present disclosure is shown. For purposes of discussion, process 300 will be referred to Figure 1A Described. For example... Figure 1AAs shown, process 300 may involve at least one of IAB node 130, first IAB donor 120-1, second IAB donor 120-2, or CN 110. First network device 310 may correspond to one of first IAB donor 120-1 or second IAB donor 120-2. Alternatively, first network device 310 may correspond to CN 110, for example, serving the AMF of IAB-UE 130 in CN 110. Second network device 320 may correspond to CN 110, for example, maintaining the AMF for the context of terminal devices in CN 110. It should be understood that although process 300 has... Figure 1A The process is described in the communication system 100, but it can also be applied to other communication scenarios.

[0073] In process 300, the first network device 310 obtains (302) a first set of identifiers associated with the connection between the Integrated Access Backhaul (IAB) node and the first IAB donor 120-1, and a second set of identifiers associated with the connection between the IAB node 130 and the second IAB donor 120-2. The first network device 310 sends (304) a message 306 including the first set of identifiers and the second set of identifiers to the second network device 320. The second network device 320 receives (308) the message 306 from the first network device 310. The second network device 320 determines (312) that the context information of at least one terminal device includes the first set of identifiers. Based on the determination that the context information of at least one terminal device includes the first set of identifiers, the second network device 320 stores (314) the second set of identifiers in the context information of at least one terminal device. At least one terminal device is in an idle state. In some embodiments, the idle state may also be referred to as a Radio Resource Control (RRC) idle state, or a Connection Management (CM) idle state, or a 5GS Mobility Management (5GMM) idle mode or state. In this way, network devices can learn about the new identifier(s) associated with the connection after migration, and their mapping relationship with the original identifier(s) associated with the original connection. Therefore, the new identifiers can be stored in the context information of the terminal device in an idle state, which can improve the reliability of IAB communication, especially for mobile IAB networks.

[0074] In some embodiments, the first identifier set may include identifiers of cells associated with the connection between IAB node 130 and the first IAB donor 120-1, such as cell identifiers associated with the F1 connection between IAB-DU 132 and the first IAB donor CU 121-1. Alternatively or additionally, the first identifier set may include identifiers of the first IAB donor 120-1, such as the global NG-RAN node ID of the first IAB donor 120-1. In other words, the first identifier set is a set of original identifiers that may correspond to the last visited RAN node and / or cell(s) of the terminal device. In some embodiments, the second identifier set may include cell identifiers associated with the connection between IAB node 130 and the second IAB donor 120-2, such as cell identifiers associated with the F1 connection between IAB-DU 132 and the first IAB donor CU 121-2. Alternatively or additionally, the second identifier set may include identifiers of the second IAB donor 120-2, such as the global NG-RAN node ID of the second IAB donor 120-2. In other words, the second set of identifiers is a set of new identifiers that can correspond to the RAN nodes and / or cells currently associated with the IAB node. In this way, when the migration of the IAB node occurs, both the original identifiers and the new identifiers can be reported, which facilitates the updating of recommended RAN nodes and / or cells for the terminal devices.

[0075] In some embodiments, the first network device 310 may be a first IAB donor 120-1. The message may be a first message. In order to obtain a first set of identifiers and a second set of identifiers, the first IAB donor 120-1 may receive a second message including the first set of identifiers and the second set of identifiers from the IAB node 130.

[0076] In some embodiments, the first network device 310 may be a second IAB donor 120-2. The message may be a first message. In order to obtain a first set of identifiers and a second set of identifiers, the second IAB donor 120-2 may receive the first set of identifiers from the first IAB donor 120-1 and receive a second message including the second set of identifiers from the IAB node 130.

[0077] In some embodiments, the first network device 310 may be the second IAB donor 120-2. The message may be the first message. In order to obtain the first set of identifiers and the second set of identifiers, the second IAB donor 120-2 may receive a second message including the first set of identifiers and the second set of identifiers from the IAB node 130 or the first IAB donor 120-1.

[0078] In some embodiments, the first network device 310 may be an AMF in CN 110. In some embodiments, the AMF may be associated with IAB node 130, for example, an AMF serving IAB-UE 131. In some embodiments, the message may be a first message. To obtain a first set of identifiers and a second set of identifiers, the AMF may receive a second message including the first set of identifiers and the second set of identifiers from IAB node 130, or from a first IAB donor 120-1, or from a second IAB donor 120-2.

[0079] In some embodiments, the first message may be sent to the second network device 320 based on a second message received from the IAB node 130. In some embodiments, the first message may be sent to the second network device 320 based on a decision made by the first network device 310. In some embodiments, the second message received from the IAB node 130 may be a request message for updating the context information of the terminal device.

[0080] In some embodiments, the first network device may be a first IAB donor 120-1. In some embodiments, the second network device 320 may include at least one AMF in CN 110. In some embodiments, the second network device 320 may send a paging message for at least one terminal device based on context information.

[0081] In some embodiments, in order to store the second set of identifiers in the context information, the second network device 320 may store the second set of identifiers in the context information of at least one terminal device, in addition to the first set of identifiers. In this way, both the original identifiers corresponding to the last visited RAN node and / or cell of the terminal device, and the new identifiers corresponding to the RAN node and / or cell currently associated with the IAB node, can be stored in the context information of the terminal device. Therefore, paging messages for the terminal device can be sent to the RAN node and / or cell currently associated with the IAB node, or to both the last visited RAN node and / or cell of the terminal device and the RAN node and / or cell currently associated with the IAB node, which improves the reliability of IAB communication.

[0082] In some embodiments, in order to store the second set of identifiers in the context information, the second network device 320 may store the second set of identifiers to replace the first set of identifiers in the context information of at least one terminal device. In this way, the original identifiers(s) in the context information of the terminal device can be replaced by the new identifiers(s). Therefore, paging messages for the terminal device can be sent to the RAN node and / or cell currently associated with the IAB node without needing to be transmitted to the RAN node and / or cell associated with the IAB node before IAB migration, which improves the reliability of IAB communication by utilizing reduced resource costs.

[0083] Figure 4A An example implementation of a process 400A for communication according to an embodiment of the present disclosure is shown. It should be noted that process 400A can be considered as being applied in an IAB network. Figure 2 Process 200 and Figure 3 A more specific example of process 300. Figure 4A An example implementation is depicted and will be described from the perspectives of UE1 450, IAB node 430, IAB donor (IAB-donor 1) 420-1, IAB donor (IAB-donor 2) 420-2, and CN device (AMF (UE)) 410-1. More specifically, IAB node 430 may be a mobile IAB node. UE1 450 may be located on a vehicle on which IAB node 430 is mounted. AMF (UE) 410-1 is the AMF node that terminates the NAS procedure of the UE (e.g., UE1 450). It should be understood that UE1 450, IAB node 430, IAB-donor 1 420-1, IAB-donor 2 420-2, and AMF (UE) 410-1 may correspond to respectively Figure 1A The terminal device 150, IAB node 130, first IAB donor 120-1, second IAB donor 120-2, and CN 110 are included. AMF (UE) 410-1 may be an AMF associated with UE1 450. It should be understood that process 400A may also include additional blocks not shown and / or omit some blocks shown, and the scope of this disclosure is not limited in this respect.

[0084] In process flow 400A, at 404, the IAB-DU of IAB node 430 can establish an F1 interface / connection with IAB-donor 1 420-1 402. The F1 SETUP REQUEST message may include the cell ID of the IAB-DU of IAB node 430. The cell ID of the IAB-DU of IAB node 430 may be the NR CGI #X associated with IAB-donor 1 420-1. At 406, UE1 450 can be connected to IAB node 430. The IAB-DU of IAB node 430 can begin serving UE1 450 using the cell ID NR CGI #X. At 408, UE1 450 can transition to the RRC idle state. At 414, as part of the UE context release procedure, IAB-donor 1 420-1 can send a UE CONTEXT RELEASE COMPLETE message 412 to AMF (UE) 410-1. The UECONTEXT RELEASE COMPLETE message 412 may include information indicating that the recommended NG-RAN node is IAB-donor 1 420-1 and the recommended cell is NR CGI #X. The AMF (UE) 410-1 can store this information for UE1 450. Specifically, the AMF (UE) 410-1 can store the following context for UE1 450: the recommended NG-RAN node is IAB-donor 1 420-1; and the recommended cell is NR CGI #X.

[0085] At 416, IAB node 430 can perform a full migration from IAB-donor 1 420-1 to IAB-donor 2 420-2. At 418, IAB-DU 132 can establish an F1 interface / connection with IAB-donor 2 420-2. The F1 SETUP REQUEST message 422 may include the cell ID of the IAB-DU of IAB node 430. The cell ID of the IAB-DU of IAB node 430 may be NR CGI #Y associated with IAB-donor 2 420-2. During the migration, UE1 450 may remain in the vehicle. In some embodiments, the cell ID of the IAB-DU of IAB node 430 may be configured via OAM in the CN or by other methods, such that IAB-donor 2 is aware of NR CGI #Y during the F1 establishment between IAB node 430 and IAB-donor 2 420-2.

[0086] At 426, IAB node 430 may initiate a first request procedure via RRC or F1 interface to update the context for (multiple) UEs in an idle state. The first request message 424 may include the old NR CGI, old IAB-donor ID, new NR CGI, and new IAB-donor ID of IAB node 430. The old NR CGI of IAB node 430 may include NR CGI #X established by IAB node 430 using F1 with IAB-donor 1 420-1. The old IAB-donor ID of IAB node 430 may include the gNB ID of IAB-donor 1 420-1. The new NR CGI of IAB node 430 may include NR CGI #Y established by IAB node 430 using F1 with IAB-donor 2 420-2. The new IAB-donor ID may include the gNB ID of IAB-donor 2 420-2.

[0087] In some embodiments, IAB node 430 does not maintain any context for the idle UE(s). IAB node 430 initiates a first request procedure regardless of the number of idle UE(s). In other words, the first request procedure is not UE-specific. The first request procedure can be executed via signaling not associated with the UE. The first request message 424 does not contain any UE ID.

[0088] At 432, IAB-donor 2 420-2 can initiate a second request procedure to the connected AMF (e.g., AMF (UE) 410-1). The second request message 428 may include the old NR CGI (i.e., #X) of IAB node 430, the old IAB-donor ID (i.e., the gNB ID of IAB-donor 1 420-1), the new NR CGI (i.e., #Y), and the new IAB-donor ID (i.e., the gNB ID of IAB-donor 2 420-2).

[0089] In some embodiments, it is assumed that the AMF of UE1 450 remains unchanged during the full migration of IAB node 430. In some embodiments, if UE1 450 goes beyond the service area of ​​its previous AMF, UE1 450 may first perform a registration update procedure.

[0090] In some embodiments, IAB-donor 2 420-2 may initiate a second request procedure based on its own decision or based on a first request message 424 received from IAB node 430. In some embodiments, IAB-donor 2 420-2 may obtain the old NR CGI and the old IAB-donor ID by other means (e.g., IAB-donor 1 420-1 provides relevant information to IAB-donor 2 420-2 via the Xn interface) and perform the second request procedure based on its own decision.

[0091] In some embodiments, the IAB donor does not maintain any context for UEs in an idle state. IAB donor 2 420-2 can initiate a second request procedure regardless of the number of UEs(s) in an idle state. In other words, the second request procedure is not UE-specific. The second request procedure can be executed via non-UE-associated signaling. The second request message 428 does not contain any UE ID.

[0092] In some embodiments, the IAB node may send a first request message 424 to IAB-donor 1 420-1, and IAB-donor 1 420-1 may then initiate a request procedure to AMF (UE) 410-1.

[0093] At 434, after receiving the second request message 428, AMF (UE) 410-1 can update the context for (any) UE. In some embodiments, if the UE's context includes a recommended cell associated with NR CGI #X, AMF (UE) 410-1 can replace NR CGI #X with a new NR CGI #Y in the UE's context. AMF (UE) 410-1 can also update the recommended NG-RAN node information using the gNB ID of IAB-donor 2 420-2. For example, AMF (UE) 410-1 can then store the following updated context for UE1 450: the recommended NG-RAN node is IAB-donor 2 420-2; and the recommended cell is NR CGI #Y.

[0094] In some embodiments, AMF (UE) 410-1 may save the identifiers of new recommended NG-RAN nodes / recommended cells as additional recommended NG-RAN node / cell information. In other words, AMF (UE) 410-1 may store the context of the following updates for UE1 450: the recommended NG-RAN nodes are IAB-donor 2 420-2 and IAB-donor 1 420-1; and the recommended cells are NR CGI #Y and #X.

[0095] In some embodiments, the second request message 428 can be sent to multiple AMFs connected to IAB-donor 2 420-2, such as in the case of network sharing, or in the case where IAB-donor 2 420-2 is connected to all AMFs in a set of AMFs within an AMF area. For example, the context of different UEs in idle state can be maintained in different AMFs. IAB-donor 2 420-2 can initiate the second request procedure to all connected AMFs.

[0096] In some embodiments, IAB node 430 may also be completely migrated to another IAB donor (e.g., IAB-donor 3), and steps similar to 416, 418, 426, 432, and 434 may be performed. The UE context stored in the AMF (e.g., the recommended NG-RAN nodes and recommended cells of UE1 450) may be updated accordingly.

[0097] At 436, AMF (UE) 410-1 can determine that UE1 450 needs to be paged, for example, due to a network-triggered service request. At 438, based on updated recommended NG-RAN node information and recommended cell information, AMF (UE) 410-1 can send a paging message 442 including the recommended cell NR CGI#Y to IAB-donor 2 420-2. In some embodiments, a conventional paging procedure can be performed. For example, at 446, based on the recommended cell NR CGI#Y in paging message 442, IAB-donor 2 420-2 can send a paging message 444 including the recommended cell NR CGI#Y to IAB node 430. At 452, based on the recommended cell NR CGI#Y in paging message 444, IAB node 430 can send a paging message 448 to page UE1 450. Therefore, paging of UE1 450 can be successfully performed via IAB-donor 2 420-2 and IAB node 430.

[0098] Through procedure 400A, the UE context for an idle UE previously connected to an IAB node is updated from reflecting the NG-RAN node of the IAB donor serving that IAB node before the IAB migration to (also) reflecting the updated cell ID of that IAB node and the NG-RAN node of the IAB donor currently connected to that IAB node. Therefore, paging of the UE can be successfully performed based on the updated UE context. In this way, paging optimization can be reused in mobile IAB networks, and the current standard can be reused with very limited changes.

[0099] Figure 4BAnother example implementation of process 400B for communication according to embodiments of the present disclosure is shown. It should be noted that process 400B can be considered as being applied to IAB networks. Figure 2 Process 200 and Figure 3 A more specific example of process 300. Figure 4B An example implementation will be depicted or described from the perspective of UE1 450, IAB node 430, IAB donor (IAB-donor 1) 420-1, IAB donor (IAB-donor 2) 420-2, CN device (AMF(UE)) 410-1, and CN device (AMF(IAB)) 410-2. More specifically, IAB node 430 may be a mobile IAB node. UE1 450 may be located on a vehicle on which IAB node 430 is mounted. AMF(IAB) 410-2 is the AMF node that terminates the NAS procedure of IAB-MT (e.g., IAB-UE of IAB node 430). AMF(UE) 410-1 is the AMF node that terminates the NAS procedure of UE (e.g., UE1 450). AMF(IAB) and AMF(UE) may be the same AMF node or different AMF nodes. It should be understood that UE1 450, IAB node 430, IAB-donor 1 420-1, and IAB-donor 2 420-2 can respectively correspond to Figure 1A The terminal device 150, IAB node 130, first IAB donor 120-1, and second IAB donor 120-2 are included. AMF (UE) 410-1 and AMF (IAB) 410-2 can be... Figure 1A In CN 110, the AMFs are associated with UE1 450 and IAB node 430, respectively. Similar reference numerals are used to indicate... Figure 4A The steps or components described herein have the same operation. Figure 4B The steps or components described herein will be omitted, and their detailed descriptions will be omitted. It should be understood that process 400B may also include additional blocks not shown and / or omit some blocks shown, and the scope of this disclosure is not limited in this respect.

[0100] In process 400B, at 426', IAB node 430 may send a first request message 424 to AMF (IAB) 410-2 via Non-Access Stratum (NAS) signaling. At 432', AMF (IAB) 410-2 may notify AMF (UE) 410-1 of the request message. In some embodiments, AMF (IAB) 410-2 may know the address of AMF (UE) 410-1. In some embodiments, AMF (UE) 410-1 and AMF (IAB) 410-2 may be the same AMF, and therefore step 432' may be omitted.

[0101] Figure 5 A flowchart of an example method 500 implemented at an IAB node according to some embodiments of the present disclosure is shown. For discussion purposes, method 500 will refer to Figure 1A It is described from the perspective of IAB node 130.

[0102] At block 510, IAB node 130 performs a migration from the first IAB donor to the second IAB donor. At block 520, IAB node 130 sends a message to the network device, which includes: a first set of identifiers associated with the connection between IAB node 130 and the first IAB donor, and a second set of identifiers associated with the connection between IAB node 130 and the second IAB donor.

[0103] In some embodiments, the first set of identifiers may include identifiers of cells associated with the connection between IAB node 130 and the first IAB donor. Alternatively or additionally, the first set of identifiers may include identifiers of the first IAB donor. In some embodiments, the second set of identifiers may include identifiers of cells associated with the connection between IAB node 130 and the second IAB donor. Alternatively or additionally, the second set of identifiers may include identifiers of the second IAB donor.

[0104] In some embodiments, the network device may be a first IAB donor. Alternatively, the network device may be a second IAB donor. Alternatively, the network device may be an Access and Mobility Management Function (AMF). In some embodiments, the message may be a request message for updating the context information of the terminal device.

[0105] Figure 6 A flowchart of an example method 600 implemented at a first network device according to some embodiments of the present disclosure is shown. For discussion purposes, method 600 will be referred to Figure 1A It is described from the perspective of the first IAB donor 120-1, the second IAB donor 120-2, or CN110.

[0106] At block 610, the first network device obtains a first set of identifiers associated with the connection between the Integrated Access Backhaul (IAB) node and the first IAB donor, and a second set of identifiers associated with the connection between the IAB node and the second IAB donor. At block 620, the first network device sends a message including the first set of identifiers and the second set of identifiers to the second network device.

[0107] In some embodiments, the first set of identifiers may include identifiers of cells associated with the connection between the IAB node and the first IAB donor. Alternatively or additionally, the first set of identifiers may include identifiers of the first IAB donor. In some embodiments, the second set of identifiers may include identifiers of cells associated with the connection between the IAB node and the second IAB donor. Alternatively or additionally, the second set of identifiers may include identifiers of the second IAB donor.

[0108] In some embodiments, the first network device may be a first IAB donor. The message may be a first message. In order to obtain a first set of identifiers and a second set of identifiers, the first IAB donor may receive a second message from the IAB node that includes the first set of identifiers and the second set of identifiers.

[0109] In some embodiments, the first network device may be a second IAB donor. To obtain a first set of identifiers and a second set of identifiers, the second IAB donor may receive the first set of identifiers from the first IAB donor and receive a message including the second set of identifiers from the IAB node.

[0110] In some embodiments, the first network device may be a second IAB donor, and the message may be a first message. In order to obtain a first set of identifiers and a second set of identifiers, the second IAB donor may receive a second message including the first set of identifiers and the second set of identifiers from the IAB node or the first IAB donor.

[0111] In some embodiments, the first network device may be an Access and Mobility Management Function (AMF). In some embodiments, the message may be a first message. To obtain a first set of identifiers and a second set of identifiers, the AMF may receive a second message including the first set of identifiers and the second set of identifiers from an IAB node, a first IAB donor, or a second IAB donor.

[0112] In some embodiments, the first message may be sent to the second network device based on a second message received from the IAB node. In some embodiments, the second message received from the IAB node may be a request message for updating context information of the terminal device. In some embodiments, the second network device may include at least one AMF.

[0113] Figure 7 A flowchart of an example method 700 implemented at a second network device according to some embodiments of the present disclosure is shown. For discussion purposes, method 700 will be referred to Figure 1A It is described from the perspective of CN 110.

[0114] At block 710, the second network device receives a message from the IAB node or the first network device, the message including: a first set of identifiers associated with the connection between the IAB node and the first IAB donor, and a second set of identifiers associated with the connection between the IAB node and the second IAB donor. At block 720, the second network device determines whether the context information of at least one terminal device includes the first set of identifiers. If so, the process proceeds to block 730. At block 730, the second network device stores the second set of identifiers in the context information of at least one terminal device, which is in an idle state. In some embodiments, the second network device may be... Figure 1A The CN 110, or the AMF within the CN 110, is used as an example. For instance, the CN 110 receives a message from an IAB node or a first network device, the message including: a first set of identifiers associated with a connection between the IAB node and a first IAB donor, and a second set of identifiers associated with a connection between the IAB node and a second IAB donor, and determines whether the context information of at least one terminal device includes the first set of identifiers. If so, the CN 110 stores the second set of identifiers in the context information of at least one terminal device, which is in an idle state.

[0115] In some embodiments, the first set of identifiers may include identifiers of cells associated with the connection between the IAB node and the first IAB donor. Alternatively or additionally, the first set of identifiers may include identifiers of the first IAB donor. In some embodiments, the second set of identifiers may include identifiers of cells associated with the connection between the IAB node and the second IAB donor. Alternatively or additionally, the second set of identifiers may include identifiers of the second IAB donor.

[0116] In some embodiments, the first network device may be a first IAB donor. Alternatively, the first network device may be a second IAB donor. Alternatively, the first network device may be an Access and Mobility Management Function (AMF).

[0117] In some embodiments, in order to store the second set of identifiers in the context information, CN 110 may store the second set of identifiers in the context information of at least one terminal device in addition to the first set of identifiers.

[0118] In some embodiments, in order to store the second set of identifiers in the context information, CN 110 may store the second set of identifiers to replace the first set of identifiers in the context information of at least one terminal device. In some embodiments, CN 110 may also send a paging message for at least one terminal device based on the context information.

[0119] In some example embodiments, the apparatus capable of performing method 500 (e.g., IAB node 130) may include components for performing the corresponding steps of method 500. These components may be implemented in any suitable form. For example, the components may be implemented as a circuit system or a software module.

[0120] In some example embodiments, the apparatus includes: components for performing a migration from a first IAB donor to a second IAB donor; and components for sending a message to a network device, the message including: a first set of identifiers associated with a connection between the apparatus and the first IAB donor, and a second set of identifiers associated with a connection between the apparatus and the second IAB donor.

[0121] In some embodiments, the first set of identifiers may include identifiers of cells associated with the connection between the device and the first IAB donor. Alternatively or additionally, the first set of identifiers may include identifiers of the first IAB donor. In some embodiments, the second set of identifiers may include identifiers of cells associated with the connection between the device and the second IAB donor. Alternatively or additionally, the second set of identifiers may include identifiers of the second IAB donor.

[0122] In some embodiments, the network device may be a first IAB donor. Alternatively, the network device may be a second IAB donor. Alternatively, the network device may be an Access and Mobility Management Function (AMF). In some embodiments, the message may be a request message for updating the context information of the terminal device.

[0123] In some example embodiments, the apparatus further includes components for performing additional steps in some example embodiments of method 500. In some example embodiments, the components include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, together with the at least one processor, cause execution of the apparatus.

[0124] In some example embodiments, the apparatus capable of performing method 600 (e.g., first IAB donor 120-1, second IAB donor 120-2, or CN 110) may include components for performing the corresponding steps of method 600. These components may be implemented in any suitable form. For example, the components may be implemented as a circuit system or a software module.

[0125] In some example embodiments, the apparatus includes: components for obtaining a first set of identifiers associated with a connection between an Integrated Access Backhaul (IAB) node and a first IAB donor, and a second set of identifiers associated with a connection between the IAB node and a second IAB donor; and components for sending a message including the first set of identifiers and the second set of identifiers to a second network device.

[0126] In some embodiments, the first set of identifiers may include identifiers of cells associated with the connection between the IAB node and the first IAB donor. Alternatively or additionally, the first set of identifiers may include identifiers of the first IAB donor. In some embodiments, the second set of identifiers may include identifiers of cells associated with the connection between the IAB node and the second IAB donor. Alternatively or additionally, the second set of identifiers may include identifiers of the second IAB donor.

[0127] In some embodiments, the apparatus may be a first IAB donor. The message may be a first message. Components for obtaining a first set of identifiers and a second set of identifiers may include components for receiving a second message from an IAB node that includes the first set of identifiers and the second set of identifiers.

[0128] In some embodiments, the apparatus may be a second IAB donor. The components for obtaining the first set of identifiers and the second set of identifiers may include: components for receiving the first set of identifiers from the first IAB donor, and components for receiving a message including the second set of identifiers from the IAB node.

[0129] In some embodiments, the apparatus may be a second IAB donor, and the message may be a first message. The components for obtaining the first and second identifier sets may include components for receiving a second message from an IAB node or the first IAB donor, comprising the first and second identifier sets.

[0130] In some embodiments, the apparatus may be an Access and Mobility Management Function (AMF). In some embodiments, the message may be a first message. Components for obtaining a first set of identifiers and a second set of identifiers may include components for receiving a second message including the first set of identifiers and the second set of identifiers from an IAB node, a first IAB donor, or a second IAB donor.

[0131] In some embodiments, the first message may be sent to the second network device based on a second message received from the IAB node. In some embodiments, the second message received from the IAB node may be a request message for updating context information of the terminal device. In some embodiments, the second network device may include at least one AMF.

[0132] In some example embodiments, the apparatus further includes components for performing additional steps in some example embodiments of method 600. In some example embodiments, the components include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to cause execution of the apparatus together with the at least one processor.

[0133] In some example embodiments, the apparatus capable of performing method 700 (e.g., CN 110) may include components for performing the corresponding steps of method 700. These components may be implemented in any suitable form. For example, the components may be implemented as a circuit system or a software module.

[0134] In some example embodiments, the apparatus includes: components for receiving a message from an Integrated Access Backhaul (IAB) node or a first network device, the message including: a first set of identifiers associated with a connection between the IAB node and a first IAB donor, and a second set of identifiers associated with a connection between the IAB node and a second IAB donor; and components for storing the second set of identifiers in the context information of at least one terminal device based on determining that the context information of at least one terminal device includes the first set of identifiers, wherein the at least one terminal device is in an idle state.

[0135] In some embodiments, the first set of identifiers may include identifiers of cells associated with the connection between the IAB node and the first IAB donor. Alternatively or additionally, the first set of identifiers may include identifiers of the first IAB donor. In some embodiments, the second set of identifiers may include identifiers of cells associated with the connection between the IAB node and the second IAB donor. Alternatively or additionally, the second set of identifiers may include identifiers of the second IAB donor.

[0136] In some embodiments, the second network device may be a first Access and Mobility Management Function (AMF). In some embodiments, the first network device may be a first IAB donor. Alternatively, the first network device may be a second IAB donor. Alternatively, the first network device may be a second AMF.

[0137] In some embodiments, the component for storing the second set of identifiers in context information may include: a component for storing the second set of identifiers in the context information of at least one terminal device in addition to the first set of identifiers.

[0138] In some embodiments, the component for storing the second set of identifiers in the context information may include: a component for storing the second set of identifiers to replace the first set of identifiers in the context information of at least one terminal device. In some embodiments, the apparatus may further include a component for sending a paging message for at least one terminal device based on the context information.

[0139] In some exemplary embodiments, the apparatus further includes components for performing additional steps in some exemplary embodiments of method 700. In some exemplary embodiments, the components include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, together with the at least one processor, cause execution of the apparatus.

[0140] Figure 8 This is a simplified block diagram of a device 800 suitable for implementing embodiments of the present disclosure. The device 800 can be provided to implement a communication device, such as... Figure 1A The figure shows CN 110, first IAB donor 120-1, second IAB donor 120-2, and IAB node 130. As shown, device 800 includes one or more processors 810, one or more memories 820 coupled to processor 810, and one or more communication modules 840 coupled to processor 810.

[0141] Communication module 840 is used for bidirectional communication. Communication module 840 has at least one antenna to facilitate communication. The communication interface can represent any interface required for communication with other network elements.

[0142] Processor 810 can be of any type suitable for a local technology network, and by way of non-limiting example, can include one or more of the following: general-purpose computer, special-purpose computer, microprocessor, digital signal processor (DSP), and processor based on a multi-core processor architecture. Device 800 can have multiple processors, such as application-specific integrated circuit chips that are time-dependent on a clock synchronized with the main processor.

[0143] Memory 820 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 824, electrically programmable read-only memory (EPROM), flash memory, hard disk, optical disc (CD), digital video disc (DVD), and other magnetic and / or optical storage. Examples of volatile memories include, but are not limited to, random access memory (RAM) 822 and other volatile memories that will not persist during power outages.

[0144] Computer program 830 includes computer-executable instructions that are executed by the associated processor 810. Program 830 may be stored in ROM 824. Processor 810 may perform any suitable actions and processes by loading program 830 into RAM 822.

[0145] Embodiments of this disclosure can be implemented via program 830, enabling device 800 to execute any process of this disclosure, as referenced. Figures 2 to 7 The embodiments of this disclosure can also be implemented in hardware or by a combination of software and hardware.

[0146] In some embodiments, program 830 may be tangibly contained in a computer-readable medium, which may be included in device 800 (such as in memory 820) or in other storage devices accessible by device 800. Device 800 may load program 830 from the computer-readable medium into RAM 822 for execution. The computer-readable medium may include any type of tangible non-volatile memory, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. Figure 9 An example of a computer-readable medium 900 in the form of a CD or DVD is shown. A program 830 is stored on the computer-readable medium.

[0147] Generally, the various embodiments of this disclosure can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects can be implemented in hardware, while others can be implemented in firmware or software, which can be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of this disclosure are shown or described as block diagrams, flowcharts, or using some other graphical representation, it should be understood that, as non-limiting examples, the blocks, apparatuses, systems, techniques, or methods described herein can be implemented in hardware, software, firmware, dedicated circuitry or logic circuitry, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0148] This disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions (such as instructions included in a program module) that are executed in a device on a target real or virtual processor to perform the functions described above. Figures 2 to 7 The method described herein. Typically, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform specific tasks or implement specific abstract data types. In various embodiments, the functionality of a program module can be combined or split among program modules as needed. The machine-executable instructions for a program module can be executed on a local or distributed device. In a distributed device, the program module can reside on both local and remote storage media.

[0149] Program code used to perform the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0150] In the context of this disclosure, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, etc.

[0151] Computer-readable media can be computer-readable signal media or computer-readable storage media. Computer-readable media can include, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination thereof. More specific examples of computer-readable storage media include electrical connections having one or more lines, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. As used herein, the term "non-transient" is a limitation of the medium itself (i.e., tangible, not signaling), not a limitation of the persistence of data storage (e.g., RAM and ROM).

[0152] Furthermore, although the operations are described in a specific order, this should not be construed as requiring that these operations be performed in the specific or sequential order shown, or that all of the operations shown be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the foregoing discussion, these details should not be considered as limiting the scope of this disclosure, but rather as descriptions of the features of particular embodiments. Certain features described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately in multiple embodiments or in any suitable sub-combination.

[0153] Although this disclosure has been described in language specific to structural features and / or methodological actions, it should be understood that the disclosure as defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as examples of implementing the claims.

Claims

1. An integrated access backhaul IAB node, comprising: At least one processor; as well as At least one memory, the at least one memory storing instructions, the instructions, when executed by the at least one processor, cause the IAB node to at least: Perform the migration from the first IAB donor to the second IAB donor; as well as Send a message to a network device, the message including: a first set of identifiers associated with the connection between the IAB node and the first IAB donor, and a second set of identifiers associated with the connection between the IAB node and the second IAB donor.

2. The IAB node of claim 1, wherein the first set of identifiers includes at least one of the following: an identifier of the cell associated with the connection between the IAB node and the first IAB donor, or an identifier of the first IAB donor.

3. The IAB node according to claim 1 or 2, wherein the second set of identifiers includes at least one of the following: an identifier of the cell associated with the connection between the IAB node and the second IAB donor, or an identifier of the second IAB donor.

4. The IAB node according to any one of claims 1 to 3, wherein the network device is one of the following: The first IAB donor; The second IAB donor; or Access and Mobility Management Function (AMF).

5. The IAB node according to any one of claims 1 to 4, wherein the message is a request message for updating the context information of the terminal device.

6. A first network device, comprising: At least one processor; as well as At least one memory storing instructions that, when executed by the at least one processor, cause the first network device to at least: Obtain a first set of identifiers associated with the connection between the integrated access backhaul IAB node and the first IAB donor, and a second set of identifiers associated with the connection between the IAB node and the second IAB donor; as well as Send a message to the second network device that includes the first set of identifiers and the second set of identifiers.

7. The first network device of claim 6, wherein the first set of identifiers includes at least one of the following: an identifier of the cell associated with the connection between the IAB node and the first IAB donor, or an identifier of the first IAB donor.

8. The first network device according to claim 6 or 7, wherein the second set of identifiers includes at least one of the following: an identifier of the cell associated with the connection between the IAB node and the second IAB donor, or an identifier of the second IAB donor.

9. The first network device according to any one of claims 6 to 8, wherein the first network device is the first IAB donor, the message is a first message, and wherein the first IAB donor is configured to obtain the first set of identifiers and the second set of identifiers by: Receive a second message from the IAB node, which includes the first set of identifiers and the second set of identifiers.

10. The first network device according to any one of claims 6 to 8, wherein the first network device is the second IAB donor, and the second IAB donor is configured to obtain the first set of identifiers and the second set of identifiers by: Receive the first set of identifiers from the first IAB donor; and Receive a message including the second set of identifiers from the IAB node.

11. The first network device according to any one of claims 6 to 8, wherein the first network device is the second IAB donor, the message is a first message, and the second IAB donor is configured to obtain the first set of identifiers and the second set of identifiers by: Receive a second message from the IAB node or the first IAB donor, which includes the first set of identifiers and the second set of identifiers.

12. The first network device according to any one of claims 6 to 8, wherein the first network device is an Access and Mobility Management Function (AMF).

13. The first network device of claim 12, wherein the message is a first message, and the AMF is configured to obtain the first set of identifiers and the second set of identifiers by: Receive a second message from the IAB node, or the first IAB donor, or the second IAB donor, including the first set of identifiers and the second set of identifiers.

14. The first network device according to claim 11 or 13, wherein the first message is sent to the second network device based on the second message received from the IAB node, or the first IAB donor, or the second IAB donor.

15. The first network device according to any one of claims 11, 13 or 14, wherein the second message received from the IAB node is a request message for updating context information of the terminal device.

16. The first network device according to any one of claims 6 to 15, wherein the second network device comprises at least one AMF.

17. A second network device, comprising: At least one processor; as well as At least one memory storing instructions that, when executed by the at least one processor, cause the second network device to at least: Receive a message from an Integrated Access Backhaul (IAB) node or a first network device, the message including: a first set of identifiers associated with the connection between the IAB node and the first IAB donor, and a second set of identifiers associated with the connection between the IAB node and the second IAB donor; as well as Based on determining that the context information of at least one terminal device includes the first set of identifiers, the second set of identifiers is stored in the context information of the at least one terminal device, wherein the at least one terminal device is in an idle state.

18. The second network device of claim 17, wherein the first set of identifiers includes at least one of the following: an identifier of the cell associated with the connection between the IAB node and the first IAB donor, or an identifier of the first IAB donor.

19. The second network device according to claim 17 or 18, wherein the second set of identifiers includes at least one of the following: an identifier of the cell associated with the connection between the IAB node and the second IAB donor node, or an identifier of the second IAB donor node.

20. The second network device according to any one of claims 17 to 19, wherein the second network device is a first access and mobility management function (AMF), and the first network device is one of the following: The first IAB donor; The second IAB donor; or Second AMF.

21. The second network device according to any one of claims 17 to 20, wherein the second network device is configured to store the second set of identifiers in the context information by: In addition to the first set of identifiers, the second set of identifiers is stored in the context information of the at least one terminal device.

22. The second network device according to any one of claims 17 to 20, wherein the second network device is configured to store the second set of identifiers in the context information by: The second set of identifiers is stored to replace the first set of identifiers in the context information of the at least one terminal device.

23. The second network device according to any one of claims 17 to 22, wherein the second network device is further configured to: Based on the context information, a paging message is sent for the at least one terminal device.

24. A method comprising: At the integrated access backhaul IAB node, a migration from the first IAB donor to the second IAB donor is performed; as well as Send a message to a network device, the message including: a first set of identifiers associated with the connection between the IAB node and the first IAB donor, and a second set of identifiers associated with the connection between the IAB node and the second IAB donor.

25. A method comprising: At the first network device, a first set of identifiers associated with the connection between the integrated access backhaul IAB node and the first IAB donor, and a second set of identifiers associated with the connection between the IAB node and the second IAB donor are obtained. as well as Send a message to the second network device that includes the first set of identifiers and the second set of identifiers.

26. A method comprising: At the second network device, a message is received from the Integrated Access Backhaul (IAB) node or the first network device, the message including: a first set of identifiers associated with the connection between the IAB node and the first IAB donor, and a second set of identifiers associated with the connection between the IAB node and the second IAB donor; and Based on determining that the context information of at least one terminal device includes the first set of identifiers, the second set of identifiers is stored in the context information of the at least one terminal device, wherein the at least one terminal device is in an idle state.

27. An apparatus comprising: A component used to perform a migration from the first IAB donor to the second IAB donor at the integrated access backhaul IAB node. as well as Components for sending messages to network devices, the messages including: a first set of identifiers associated with the connection between the IAB node and the first IAB donor, and a second set of identifiers associated with the connection between the IAB node and the second IAB donor.

28. An apparatus comprising: Components for obtaining, at a first network device, a first set of identifiers associated with the connection between the Integrated Access Backhaul IAB node and the first IAB donor, and a second set of identifiers associated with the connection between the IAB node and the second IAB donor; as well as A component for sending a message including the first set of identifiers and the second set of identifiers to a second network device.

29. An apparatus comprising: Components for receiving messages at a second network device from an Integrated Access Backhaul (IAB) node or a first network device, the messages including: a first set of identifiers associated with a connection between the IAB node and a first IAB donor, and a second set of identifiers associated with a connection between the IAB node and a second IAB donor; and A component for storing the second set of identifiers in the context information of the at least one terminal device based on determining that the context information of the at least one terminal device includes the first set of identifiers, wherein the at least one terminal device is in an idle state.

30. A non-transitory computer-readable medium comprising program instructions that, when executed by a device, cause the device to perform at least the method according to any one of claims 24 to 26.

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