Switching between devices served by IAB nodes

Abstract

Example embodiments of the present disclosure relate to handover of (multiple) devices served by an integrated access and backhaul (IAB) node. A first device receives indication information indicating a change in service availability of a second device serving at least one third device. The first device determines whether handover of the at least one third device from the second device is to be triggered based on the indication information. Based on the determination that handover of the at least one third device is to be triggered, the first device transmits handover information to the second device, the handover information indicating at least one fourth device selected for handover of the at least one third device from the second device.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the field of telecommunications, and in particular to a switching method, device, apparatus, and computer-readable storage medium for a device(s) served by an Integrated Access and Backhaul (IAB) node. Background Art

[0002] Integrated Access and Backhaul (IAB) has been introduced into communication systems as a key enabler for fast and cost-effective deployment. For example, IAB can enable dense mmWave deployments outdoors. IAB nodes behave like base stations to provide a radio interface to terminal devices within their coverage area. IAB nodes can use the same spectrum and air interface for access and backhaul, creating a single-hop or hierarchical multi-hop network between sites. Each hop terminates at a donor node called an IAB donor node (or IAB donor). IAB donor nodes can be connected to the core network via a fixed backhaul.

[0003] The handover process of the terminal device may be triggered from one IAB node to another IAB node. Currently, as mobile IAB nodes are anticipated in the development of communication systems, the handover process faces new challenges. Summary of the invention

[0004] In general, example embodiments of the present disclosure provide a handover solution for device(s) served by an IAB node. Embodiments that do not fall within the scope of the claims, if any, are to be construed as examples that aid in understanding the various embodiments of the present disclosure.

[0005] In a first aspect, a first device is provided. The first device includes at least one processor; and at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the first device to: receive indication information indicating a change in service availability of a second device, the second device serving at least one third device; determine whether switching of the at least one third device from the second device is to be triggered based on the indication information; and transmit switching information to the second device based on the determination that switching of the at least one third device is to be triggered, the switching information indicating at least one fourth device selected for switching of the at least one third device from the second device.

[0006] In a second aspect, a second device is provided. The second device includes at least one processor; and at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the second device to receive switching information from a first device independently of a measurement report from at least one third device, the switching information indicating at least one fourth device selected for switching of at least one third device from the second device, the second device serving the at least one third device; and transmit reconfiguration information to at least one third device, the reconfiguration information being used to configure the at least one third device to perform switching from the second device to the at least one fourth device.

[0007] In a third aspect, a fifth device is provided. A second device includes at least one processor; and at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the fifth device to receive indication information indicating a change in service availability of the second device, the second device serving at least one third device and being managed by the fifth device; determine whether the second device is to be replaced based on the indication information; based on the determination that the second device is to be replaced, activate the fourth device to replace the second device to serve the at least one third device; and cause additional indication information to be transmitted to the first device connected to the second device, the additional indication information indicating that the fourth device is to replace the second device to serve the at least one third device.

[0008] In a fourth aspect, a method is provided. The method includes receiving, at a first device, indication information indicating a change in service availability of a second device, the second device serving at least one third device; determining whether a handover of the at least one third device from the second device is to be triggered based on the indication information; and transmitting handover information to the second device based on the determination that the handover of the at least one third device is to be triggered, the handover information indicating at least one fourth device selected for the handover of the at least one third device from the second device.

[0009] In a fifth aspect, a method is provided. The method includes: receiving, at a second device, switching information from a first device independently of a measurement report from at least one third device, the switching information indicating at least one fourth device selected for switching of the at least one third device from the second device, the second device serving the at least one third device; and transmitting reconfiguration information to the at least one third device, the reconfiguration information being used to configure the at least one third device to perform switching from the second device to the at least one fourth device.

[0010] In a sixth aspect, a method is provided. The method includes: receiving, at a fifth device, indication information indicating a change in service availability of a second device, the second device serving at least one third device and being managed by the fifth device; determining whether the second device is to be replaced based on the indication information; activating a fourth device to replace the second device to serve the at least one third device in accordance with the determination that the second device is to be replaced; and causing additional indication information to be transmitted to a first device connected to the second device, the additional indication information indicating that the fourth device is to replace the second device to serve the at least one third device.

[0011] In a seventh aspect, a first device is provided. The first device includes: a component for receiving indication information indicating a change in service availability of a second device, the second device serving at least one third device; a component for determining whether switching of the at least one third device from the second device is to be triggered based on the indication information; and a component for transmitting switching information to the second device based on the determination that switching of the at least one third device is to be triggered, the switching information indicating at least one fourth device selected for switching of the at least one third device from the second device.

[0012] In an eighth aspect, a second device is provided. The second device includes: a component for receiving switching information from a first device independently of a measurement report from at least one third device, the switching information indicating at least one fourth device selected for switching of the at least one third device from the second device, the second device serving the at least one third device; and a component for transmitting reconfiguration information to the at least one third device, the reconfiguration information being used to configure the at least one third device to perform switching from the second device to the at least one fourth device.

[0013] In a ninth aspect, a fifth device is provided. The fifth device includes: a component for receiving indication information indicating a change in service availability of a second device, the second device serving at least one third device and being managed by the fifth device; a component for determining whether the second device is to be replaced based on the indication information; a component for activating a fourth device to replace the second device to serve the at least one third device based on the determination that the second device is to be replaced; and a component for causing additional indication information to be transmitted to a first device connected to the second device, the additional indication information indicating that the fourth device is to replace the second device to serve the at least one third device.

[0014] In a tenth aspect, a computer-readable medium is provided, wherein the computer-readable medium comprises program instructions for causing an apparatus to at least execute the method according to any one of the fourth aspect, the fifth aspect and the sixth aspect.

[0015] It should be understood that the invention summary is not intended to determine the key or essential features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0017] Figure 1 An example communication environment is shown in which example embodiments of the present disclosure may be implemented;

[0018] Figure 2 shows a signaling flow for handover of (multiple) devices according to some example embodiments of the present disclosure;

[0019] Figure 3 Another example communication environment in which example embodiments of the present disclosure may be implemented is shown;

[0020] Figure 4 shows a signaling flow for activating a new device according to some example embodiments of the present disclosure;

[0021] Figure 5 A flowchart showing a method implemented at a first device according to some other example embodiments of the present disclosure;

[0022] Figure 6 A flowchart showing a method implemented at a second device according to some other example embodiments of the present disclosure;

[0023] Figure 7 A flowchart showing a method implemented at a fifth device according to some other example embodiments of the present disclosure;

[0024] Figure 8 shows a simplified block diagram of a device suitable for implementing an example embodiment of the present disclosure; and

[0025] Fig. 9 A block diagram of an example computer-readable medium is shown according to some example embodiments of the present disclosure.

[0026] Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0027] The principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are described only to illustrate and help those skilled in the art to understand and implement the present disclosure, and do not represent any limitation on the scope of the present disclosure. The embodiments described herein can be implemented in various other ways except for the way described below.

[0028] In the following description and claims, unless defined otherwise, 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 belongs.

[0029] In this disclosure, references to "one embodiment," "an embodiment," and "an example embodiment" indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment must include the particular feature, structure, or characteristic. In addition, such phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, those skilled in the art believe that it is within the knowledge of those skilled in the art to affect such feature, structure, or characteristic in conjunction with other embodiments, whether or not explicitly described.

[0030] 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 only used to distinguish one element from another element. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the exemplary embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0031] The terms used herein are only used to describe specific embodiments and are not intended to limit the example embodiments. As used herein, the singular forms "a", "an", and "the" also include the plural forms, unless the context clearly indicates otherwise. It is further understood that the terms "comprises", "comprising", "has", "having", "includes", and / or "including" when used herein specify the presence of the features, elements, and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0032] As used in this application, the term "circuitry" may refer to one, more, or all of the following:

[0033] (a) a pure hardware circuit implementation (such as an implementation using only analog and / or digital circuitry), and

[0034] (b) a combination of hardware circuitry and software such as (where applicable):

[0035] (i) a combination of analog and / or digital hardware circuits and software / firmware, and

[0036] (ii) any portion of a hardware processor(s) with software (including digital signal processor(s), software and memory(s) that work together to cause a device (such as a mobile phone or server) to perform various functions), and

[0037] (c) Hardware circuit(s) and / or processor(s), such as microprocessor(s) or portion(s) of microprocessor(s), which requires software (e.g., firmware)

[0038] The software can be saved when no operation is needed.

[0039] This definition of circuitry applies to all uses of the term in this application, including in any claims. As another example, as used in this application, the term circuitry also covers an implementation of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its accompanying software and / or firmware. For example, if applicable to a particular claim element, the term circuitry also covers a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0040] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard, such as New Radio (NR), Long Term Evolution (LTE), Advanced LTE (LTE-a), Wideband Code Division Multiple Access (WCDMA), High Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), etc. In addition, the communication between the terminal device and the network device in the communication network can be performed according to any suitable generation of communication protocol, including but not limited to the first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, future fifth generation (5G) communication protocol, and / or any other protocol currently known or to be developed in the future. The embodiments of the present disclosure can be applied to various communication systems. In view of the rapid development of communication, there will certainly be future types of communication technologies and systems that can embody the present disclosure. The scope of the present disclosure should not be limited to the above-mentioned systems.

[0041] As used herein, the term "network device" refers to a node in a communication network through which a terminal device accesses the network and receives services from the network. A network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR NB (also referred to as a gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), a relay, an integrated access and backhaul (IAB) node, a low-power node (such as a femto, a micro, etc.), a non-terrestrial network (NTN) or a non-terrestrial network device (such as a satellite network device, a low earth orbit (LEO) satellite, and a geosynchronous orbit (GEO) satellite), an aircraft network device, etc., depending on the terminology and technology applied. In some example embodiments, a radio access network (RAN) split architecture includes a centralized unit (CU) and a distributed unit (DU) at an IAB donor node. An IAB node includes a mobile terminal (IAB-MT) portion that behaves similarly to a UE toward a parent node, and the DU portion of the IAB node behaves similarly to a base station toward a next-hop IAB node.

[0042] The term "terminal device" refers to any terminal device capable of wireless communication. As an example and not limitation, a terminal device may also be referred to as a communication device, a user equipment (UE), a subscriber station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT). The terminal device may include, but is not limited to, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet computer, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device (such as a digital camera), a game terminal device, a music storage and playback device, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, a laptop embedded device (LEE), a laptop vehicle-mounted device (LME), a USB dongle, a smart device, a wireless customer premises equipment (CPE), an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical equipment and applications (e.g., remote surgery), industrial equipment and applications (e.g., robots and / or other wireless devices operating in the context of an industrial and / or automated processing chain), consumer electronic devices, devices operating on commercial and / or industrial wireless networks, etc. The terminal device may also correspond to the mobile terminal (MT) part of an IAB node (eg, a relay node).In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

[0043] As used herein, the term "resource", "transmission resource", "resource block", "physical resource block (PRB)", "uplink resource" or "downlink resource" may refer to any resource used to perform communication (e.g., communication between a terminal device and a network device), such as a resource in the time domain, a resource in the frequency domain, a resource in the space domain, a resource in the code domain, or any other resource that enables communication. In the following, resources in both the frequency domain and the time domain will be used as examples of transmission resources to describe some example embodiments of the present disclosure. Note that the example embodiments of the present disclosure are also applicable to other resources in other domains.

[0044] Example Environment

[0045] In communication systems, the deployment of new base stations can be a costly and time-consuming task that includes network planning, site acquisition, and the provision of backhaul connectivity. IAB nodes have been designated to improve coverage and capacity issues in the network, allowing for faster and more flexible deployment of additional base stations using wireless backhaul. Figure 1 An example communication environment 100 in which embodiments of the present disclosure may be implemented is shown. The communication environment 100 shows an example IAB architecture, which includes one or more first devices (e.g., first devices 110, 115), a second device 120, one or more third devices (e.g., third devices 130-1, 130-2, ..., 130-N, where N is an integer greater than or equal to 1), one or more fourth devices (e.g., fourth devices 140-1, 140-2, 140-3), and a fifth device 150. For ease of discussion, the third devices 130-1, 130-2, ..., 130-N are collectively or individually referred to as third devices 130; and the fourth devices 140-1, 140-2, 140-3 are collectively or individually referred to as fourth devices 140.

[0046] exist Figure 1 In the example of , the first device 110 is shown as an IAB donor node (also referred to as an IAB donor), the second device 120 and the fourth device 140 are shown as IAB nodes (also referred to as IAB nodes), and the third device 130 is shown as a terminal device. It should be understood that the number of the first device, the second device, the third device, the fourth device, and the fifth device is given for the purpose of illustration and does not impose any limitation on the present disclosure. The communication environment 100 may include any suitable number of devices suitable for implementing the implementation of the present disclosure.

[0047] In an example IAB architecture, a first device 110 as an IAB donor node serves one or more other devices that may be IAB nodes. For example, the first device 110 serves the second device 120 and the fourth devices 140-1, 140-2; and the first device 115 serves the fourth device 140-3. The IAB donor node and the IAB node can be arranged in a hierarchical structure with one or more hops. The terminating hop is an IAB donor node, which is connected to the CN 160 by means of a backhaul (e.g., through an NG interface to a 5G core network (CN)). Although not shown, one or more other network devices (such as gNBs and eNBs) may also be connected to the CN 160. In addition, one or more IAB donor nodes and their child IAB nodes may also be connected to the CN 160.

[0048] As shown, first device 110 includes DU 111 and CU 112, and first device 115 includes DU 116 and CU 118. In some example embodiments, DU 111 has an F1 connection with CU 112. DU 111 or 116 serves one or more cells in the same manner as a DU having a fixed (non-wireless) connection to CU 112 or 118. The cell served by DU 111 or 116 may broadcast control signals, such as a synchronization signal block (SSB) for downlink (DL) synchronization, system information (e.g., a master information block (MIB), system information block 1 (SIB1), etc.). Therefore, from the perspective of the UE, the cell served by DU 111 may be considered a normal cell.

[0049] The second device 120 includes a DU 121 and a MT 122. Similarly, the fourth device 140-1 includes a MT 142-1 and a DU 141-1, the fourth device 140-2 includes a MT 142-2 and a DU 141-2, and the fourth device 140-3 includes a MT 142-3 and a DU 141-3, wherein the MTs 142-1, 142-2, 142-3 are collectively or individually referred to as MT 142, and the DUs 141-1, 141-2, 141-3 are collectively or individually referred to as DU 141. The MTs 122, 142-1, 142-2, 142-3 may behave like terminal devices toward a parent node in a hierarchical structure. The DUs 121, 141-1, 141-2, 141-3 may behave like network devices toward a next-hop IAB node, for example by establishing a connection via a Uu interface. In some example embodiments, DUs 121, 141-1, 141-2 have an F1 connection with CU 112 of first device 110, and DU 141-3 has an F1 connection with CU 116 of first device 115. DUs 121 and 141 serve one or more cells in the same manner as DUs having a fixed (non-wireless) connection to CU 112. On the access link, the second device 120 and the fourth device 140-1, 140-2, 140-3 may behave like network devices to provide a radio interface (e.g., a Uu interface) for terminal devices in their coverage area. Although only the second device 120 is shown as serving the third device 130, one or more third devices 130 may also be served by the fourth device 140-1, 140-2, for example, via a Uu interface. Each DU of the second device 120 and the fourth device 140 - 1 , 140 - 2 , or the fourth device 140 - 3 may also be connected to the CU 112 or 118 of the first device 110 or 115 , for example, via an F1 interface.

[0050] It should be understood that although Figure 1 In the example of FIG. 5 , the DU, CU and MT are shown to be implemented on respective devices, but each of the DU, CU and MT may also be implemented on a separate entity.

[0051] Communications in the communication environment 100 may be implemented according to any (multiple) appropriate 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 Institute of Electrical and Electronics Engineers (IEEE) 802.11, and / or any other protocol currently known or to be developed in the future. In addition, communications may utilize any appropriate 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 OFDM (DFT-s-OFDM) and / or any other technology currently known or to be developed in the future.

[0052] Typically, during operation, the handover process is triggered based on measurement reports from the terminal device. The measurement reports may include the signal strength of the current serving cell and neighboring cells of the terminal device. If it is determined that the signal strength of the serving cell is reduced and / or if it is found that the neighboring cell can better serve the terminal device, the terminal device is notified of the handover decision from the serving cell to the neighboring cell. There may be different types of handover (HO), such as baseline HO (BHO), conditional HO (CHO), dual active protocol stack (DAPS) HO, and make-before-break HO.

[0053] In the IAB architecture, the handover process of the terminal device can be triggered from one IAB node toward another IAB node or an IAB donor. However, unlike traditional fixed base stations, IAB nodes may be movable. As a specific example, an IAB node may be located on a mobile object such as a bus or a train to provide radio access to terminal devices inside or outside the mobile object. This means that one or more cells provided by the mobile IAB node are "moving". A specific operating mode of a mobile IAB node is that when the IAB node is stationary or moving slowly, the IAB node can be active for serving terminal devices located in a specific coverage area. Such an IAB node may be referred to as a nomadic IAB node, which may be considered a special type of mobile IAB node. Nomadic IAB nodes may be used to provide coverage and / or capacity enhancement. For example, when a vehicle is parked, a nomadic IAB node may serve terminal devices outside the vehicle.

[0054] However, deploying IAB nodes in or on mobile objects may bring new problems to network planning. The inventors have found that due to the mobility of IAB nodes, their availability in the service area can change dynamically, which may be a challenge for handover management of terminal devices. In one scenario, when a mobile IAB node leaves, for example, when a vehicle into which the mobile IAB node is integrated is driven away, the terminal devices served by the IAB node (although they may be stationary) will experience a sudden movement relative to the IAB node. In this case, the terminal device may experience a radio link failure (RLF) and must start searching for other suitable cells, which means additional delays and transient signaling increases.

[0055] In addition to mobility, the power supply and flexible deployment of IAB nodes may also lead to potential sudden service interruptions in some cases, which may also cause service discontinuity for the served end devices. These sudden changes in IAB nodes may be beyond the control of network planning.

[0056] According to conventional switching based on measurement reports from terminal devices, terminal devices cannot predict when the signal strength of the serving IAB node will decrease. Therefore, terminal devices are likely to experience service discontinuity because they cannot transition to the active cell in time. It is desirable to provide a smooth transition to a new IAB node for terminal devices when the serving IAB node becomes unavailable to achieve service continuity for the terminal devices.

[0057] How switching works and example signaling flows

[0058] According to some example embodiments of the present disclosure, a switching solution is provided. In this solution, switching preparation is foreseen on the network side and can be triggered independently of measurement reports from terminal devices. Specifically, the switching decision is triggered based on indication information, which indicates an expected change in service availability of a device (e.g., an IAB node) serving one or more other devices. Since the change in service availability is indicated before (multiple) served devices are affected, the switching of (multiple) served devices can be prepared before the serving device is unavailable and before (multiple) served devices are affected. Early switching preparation can ensure service continuity of the served devices.

[0059] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0060] Reference now Figure 2 , Figure 2 FIG. 2 shows a signaling flow 200 for switching of (a plurality of) devices according to some example embodiments of the present disclosure. For the purpose of discussion, reference will be made to Figure 1Describe signaling flow 200. Signaling flow 200 involves first device 110, second device 120, one or more third devices 130 served by second device 120, one or more fourth devices 240, and fifth device 150. Fourth device(s) 240 may or may not include fourth device(s) in environment 100, which will be discussed below.

[0061] It should be understood that although the signaling flow 200 is described with the first device 110 as a donor node in the IAB-based architecture, the signaling flow 200 is also applicable to other first devices, such as the first device 115. Figure 1 The communication environment 100 is described in detail, but the signaling flow can also be applied to other communication scenarios.

[0062] In the signaling flow 200, the first device 110 is configured for handover control of one or more third devices 130 served by the second device 120. In some example embodiments, the first device 110 is an IAB donor node, and the second device 120 is an IAB node controlled by the first device 110. In the signaling flow 200, the fifth device 150 is configured to manage the first device 110, the second device 120 and / or (multiple) fourth devices 240. In some example embodiments of the present disclosure, the fifth device 150 may be a core network entity in the CN 160, such as an access and mobility function (AMF). In some example embodiments of the present disclosure, the fifth device 150 is a management entity, such as an operation management and maintenance (OAM) entity. In some example embodiments of the present disclosure, the fifth device 150 may obtain auxiliary information from a positioning entity (e.g., a location management function (LMF)) to obtain information about the physical location of the second device 120.

[0063] In operation, the first device 110 receives 205 indication information indicating a change in service availability of the second device 120. In some example embodiments of the present disclosure, such indication information may be received from a positioning entity.

[0064] As described below, the indication information is considered as a triggering event, which is used to trigger the switching of one or more third devices 130 served by the second device 120. In an example embodiment of the present disclosure, the switching decision can be made by directly observing the service availability of the second device 120 on the network side, independent of the measurement report from the (multiple) third devices 130. In some example embodiments, the indication information may indicate whether the second device 120 will become unavailable to serve some or all of the third devices 130.

[0065] In some example embodiments, the indication information may be provided to the first device 110 earlier than the measurement report from the third device 130 that triggers the handover decision. In this way, although there are no radio conditions for triggering the handover of the third device(s) 130, such indication information may be used to proactively move the third device(s) 130 from the second device 120 that is about to become unavailable to a new device that is available to serve the third device(s) 130.

[0066] Due to various reasons, the second device 120 may become unavailable to serve one or more third devices 130, and thus the indication information may indicate how the service availability changes from various sources (eg, different devices / entities).Some example embodiments will be described below.

[0067] In some example embodiments, the indication information may include information indicating that the second device 120 is to move out of the service area for (multiple) third devices 130. In some example embodiments, the second device 120 may be mobile, for example, a mobile IAB node, or specifically, a nomadic IAB node. In some example embodiments, the second device 120 may be a node with a wireless backhaul, such as a mobile or nomadic relay.

[0068] The mobility of the second device 120 may be caused by the mobility of the object into which the second device 120 is integrated. For example, the second device 120 may be integrated in a vehicle such as a car-sharing fleet or a taxi fleet. Currently, vehicles with batteries or generators can be used as flexible and abundantly available resources for deploying IAB nodes. Owners of larger fleets (i.e., buses, taxis, or rental cars) may use their vehicles as hosting platforms or may even operate IAB nodes on their own. In this case, the departure of the vehicle may cause the second device 120 to move. Of course, the second device 120 may be located in other movable objects such as buses, trains, drones (UAVs), and may therefore move with them. In other examples, the second device 120 may be portable and moved by its owner.

[0069] Due to the mobility of the second device 120, the service area provided by the second device 120 may move with the movement of the second device 120, thereby causing the service of a certain (certain) third device 130 located in the original coverage area to be unavailable. Therefore, actively providing the first device 110 with information indicating the movement can help the first device 110 make a switching decision for the (multiple) third devices 130.

[0070] The information indicating movement may be provided to the first device 110 before the second device 120 begins to move or shortly after the second device 120 moves, during which time the third device(s) 130 may not detect a significant decrease in signal strength from the second device 120 in its measurement report(s).

[0071] In some example embodiments, the first device 110 may receive 205 from the second device 120 information indicating movement of the second device 120. Figure 2 As shown, the second device 120 may transmit 210 indication information to the first device 110, the indication information including information indicating the movement of the second device 120. In some example embodiments, the information may be transmitted to the first device 110 by the MT 122 of the second device 120.

[0072] The second device 120 can know when its service availability will be changed, for example, due to its movement or battery level. In some example embodiments, one or more indications of the movement of the object into which the second device 120 is integrated can be provided to the second device 120. An application system can be run on the object to provide such indications. For example, a motion sensor system positioned with the second device 120, a position change indicated from a positioning system or service (e.g., a global positioning system (GPS) or a 5G positioning service), and / or a state change of an onboard navigation system can be used as an indication of the movement of the second device 120. In some example embodiments, the second device 120 can be equipped with a motion sensor to detect its movement.

[0073] Alternatively or additionally, information indicating the movement of the second device 120 may be provided by a third-party entity that monitors the mobility of an object located in association with the second device 120. For example, if the second device 120 is installed in a vehicle, an application system such as a motion sensor system, a positioning system, or a navigation system in the vehicle may monitor whether the vehicle is moving. The motion sensor system, the positioning system, the autonomous driving system, or the navigation system may provide an indication of the movement of the vehicle to the first device 110 (which directly indicates the movement of the second device 120). In some cases, some application systems may be developed to monitor the status of an object into which the second device 120 may be integrated. For example, a car rental application system may notify that a vehicle is booked by a customer or that the engine of the vehicle is started.

[0074] In some example embodiments, information indicating the movement of second device 120 may be notified to fifth device 150, which may then forward the information to first device 110. Figure 2 As shown, the fifth device 150 may transmit 215 indication information to the first device 110 , the indication information including information indicating the movement of the second device 120 .

[0075] The CN 160 or the network management plane may have an exposure function that can obtain such information from a third-party entity that monitors the mobility of an object located in association with the second device 120. The fifth device 150 (e.g., an OAM entity in a management plane or domain, or a core network entity in the CN 160) may transmit information indicating the movement to the first device 110. Examples of entities that monitor mobility may include a motion sensor system in a vehicle, a positioning system, or a navigation system, other application systems developed to monitor the status of an object into which the second device 120 may be integrated.

[0076] In some example embodiments, in addition to or as an alternative to the information indicating the movement, the indication information to be used as a triggering event for the handover may include information indicating that the second device 120 is about to fail. Due to a hardware failure, a software failure, etc., the second device 120 may become unavailable to serve the third device 130. The information indicating the failure may be transmitted from the second device 120 to the first device 110 at 210, or transmitted from the fifth device 150 to the first device 110 in a signaling flow at 215, or may be transmitted to the first device 110 by any third party entity (such as an application system) that monitors the operating status of the second device 120.

[0077] Alternatively or additionally, in some example embodiments, the indication information may include information indicating that the second device 120 is to be deactivated. The deactivation of the second device 120 may be caused by the second device 120 being turned off, the battery of the second device 100 being exhausted, and / or other reasons. In one example, a user-initiated switch on a dashboard for opting-in / out services may control the activation and deactivation of the second device 120. As another example, the deactivation of the second device 120 may be triggered based on the expiration of a timer and / or any other event. In some example embodiments, both the DU 121 and the MT 122 of the second device 120 may be deactivated. Alternatively, in some example embodiments, the deactivation of the second device 120 indicates that the DU 121 of the second device 120 is partially deactivated, while the MT 122 portion remains active and maintains a connection with the network. This may indicate that only (a plurality of) served cells are turned off, but the MT 122 remains connected to the network to allow for possible later activation of the DU (e.g., at another location).

[0078] A third-party entity (such as an application system) may monitor the operating state of the second device 120 or the energy state of the power supply of the second device. If such an entity detects that the second device 120 is to be deactivated or its service is terminated, the entity may be able to provide information indicating the deactivation. The information indicating the deactivation of the second device 120 may be provided by the application system to the second device 120 or the fifth device 150, which may then report it to the first device 110. In some other examples, the application system may also transmit information indicating the deactivation to the second device 120, if possible.

[0079] Alternatively or additionally, in some example embodiments, the indication information may include information indicating that one or more other devices are configured to replace the second device 120 to serve the one or more third devices 130. The device configured to replace the second device 120 is also referred to as a fourth device. In the case where the information indicating the replacement is received, the fourth device may be a new device added to the IAB-based architecture ( Figure 1 not shown), for example Figure 1 In some example embodiments, the fourth device (s) 240 may include a new device that is activated to replace the second device 120, which will be referred to below. Figure 3 and Figure 4 Detailed Description In some other example embodiments, the fourth device(s) 240 may include new devices connected to different IAB donor nodes.

[0080] In some example embodiments, the decision to replace the second device 120 with one or more other devices may be made by the fifth device 150. For network planning and management purposes, the fifth device 150 may decide to replace the second device 120. Figure 3 and Figure 4 A detailed discussion regarding deciding to replace the second device 120 is provided.

[0081] In some example embodiments, upon determining to replace second device 120, fifth device 150 may transmit corresponding indication information to first device 110. Alternatively, one or more fourth devices configured to replace second device 120 may transmit corresponding indication information to first device 110. In some example embodiments, fifth device 150 may indicate to second device 120 that it will be replaced by one or more fourth devices, and second device 120 may transmit corresponding indication information to first device 110.

[0082] In some example embodiments, the second device 120 (e.g., the MT 122 of the second device 120) may detect one or more new neighboring cells that provide strong signal strength, for example, after one or more fourth devices are activated. The second device 120 may transmit a measurement report to the first device 110 to indicate the signal strength with the one or more fourth devices. The first device 110 may predict from the information indicating the movement, failure, or deactivation that the service second device 120 is about to leave or deactivate. Therefore, the first device 110 may assume that one or more third devices 130 currently served by the second device 120 may also have strong reception of the (multiple) new neighboring cells of the one or more fourth devices. In this case, the measurement report of the MT 122 may also be used as indication information to indicate that when the service availability of the second device 120 changes, there are one or more devices suitable for serving the one or more third devices 130 near the location of the second device 120.

[0083] In the above example embodiments, various types of indication information are provided to serve as triggering events for switching. Depending on the type of indication information, the indication information may be provided to the first device 110 from various sources to trigger switching. As described above, the various sources may include the second device 120 and the fifth device 150 (as shown in the signaling flow 200), an entity monitoring the mobility of an object located in association with the second device 120, and / or a device (or devices) configured to replace the second device 120. Some other sources of indication information will be discussed further below.

[0084] After receiving the indication information indicating the change in service availability of the second device 120, the first device 110 determines 220 whether switching of the third device(s) 130 from the second device is to be triggered based on the indication information. In some example embodiments, the CU 112 of the first device 110 may use the indication information to make a switching decision.

[0085] If the indication information indicates that the service availability becomes or will become unavailable for one or more third devices 130, the first device 110 determines that handover of the third device(s) 130 from the second device 120 is to be triggered. In this case, the first device 110 transmits 225 handover information to the second device 120, the handover information indicating at least one fourth device 240 selected for handover of the third device(s) 130 from the second device 120. Note that in this regard, in most cases, there will be no triggering of a conventional handover (which will be triggered based on measurement reports(s) from the served third device(s) 130) for the served third device(s) 130.

[0086] In some example embodiments, if the second device 120 is to move out of the coverage area, as indicated by the indication information, the first device 110 may determine to trigger a handover of all third devices 130 located in the coverage area. In some example embodiments, if the second device 120 is to fail or become inoperative, as indicated by the indication information, the first device 110 may determine to trigger a handover of all third devices 130 currently served by the second device 120.

[0087] In some example embodiments, if the second device 120 is to be completely replaced by one or more fourth devices, as indicated by the indication information, the switching of all third devices 130 may be triggered. In some cases, the indication information may indicate that the one or more fourth devices are configured to replace the second device 120 to serve some but not all third devices 130, for example, in order to alleviate the high local network load of the second device 120. In this case, the indicated switching of the third device(s) 130 may be triggered by the first device 110.

[0088] In some example embodiments, upon determining that a handover of the (multiple) third device 130 is to be triggered, the first device 110 may select one or more fourth devices 240 as the (multiple) targets of the handover. In an example embodiment, the (multiple) fourth devices 240 selected as the (multiple) handover targets of the (multiple) third devices 130 may include one or more fourth devices 140 controlled and served by the first device 110. In other words, among all candidate devices, the first device 110 may select one or more fourth devices 140 (e.g., fourth devices 140-1, 140-2) connected thereto and of course available to serve the (multiple) third devices 130. By selecting the (multiple) fourth devices 140 connected to the same first device 110 as the second device 120, intra-CU handover of the (multiple) third device 130 may be performed between IAB nodes, which may reduce signaling overhead during the handover process.

[0089] In an example embodiment, the first device 110 may also determine one or more fourth devices (e.g., IAB nodes) controlled by other devices (such as different IAB donor nodes) for handover. For example, if such an available fourth device connected to the first device 110 is not found, the first device 110 may determine a fourth device(s) controlled by another first device. Figure 1In the communication environment 100 of FIG. 1 , the first device 110 may select the fourth device 140-3 connected to another first device 115 as a switching target. In this case, an inter-CU switching of the (multiple) third device 130 may be performed. In some example embodiments, the (multiple) fourth device 240 selected as the (multiple) target of the switching of the (multiple) third device 130 may include a static network device such as a gNB or an eNB.

[0090] In some example embodiments, the first device 110 may receive one or more measurement reports from the third device(s) 130, which may be used to determine an appropriate fourth device(s) 240 for handover. The measurement report(s) from the third device(s) 130 may indicate the signal strength(s) with one or more neighboring cells served by other devices other than the second device 120. In some example embodiments, the first device 110 may receive one or more measurement reports from the second device 120 (e.g., from the MT 122 of the second device 120), which indicates the signal strength(s) between the cell(s) served by the second device 120 and one or more neighboring cells served by other devices other than the second device 120. Based on the measurement report(s), the first device 110 may select one or more fourth devices 240 from the devices with strong signal strength. Alternatively or additionally, proximity information of other available devices relative to the second device 120 may be used to select an appropriate fourth device. For example, the first device 110 may select a fourth device 240 that is close to the second device 120.

[0091] In some example embodiments, if switching of third device(s) 130 is triggered by information indicating replacement, first device 110 may determine one or more fourth devices 240 as the device(s) indicated in the information to replace second device 120 .

[0092] In some example embodiments, multiple fourth devices 240 may be selected to perform handover for third device 130. For example, if CHO is to be performed at third device 130, the decision of the best target device for handover is left to third device 130. In this embodiment, multiple handover preparations may be performed by selecting multiple fourth devices 240 for at least some of third devices 130.

[0093] In some example embodiments, multiple third devices 130 may be distributed in the coverage area, so not all third devices 130 have the same radio conditions with the same (multiple) fourth devices 240. Therefore, in some example embodiments, first device 110 may select multiple groups of fourth devices 240 for third devices 130, each group of fourth devices 240 being selected for handover of at least one third device 130. In this way, for a subset of third devices 130, one or more suitable fourth devices 240 may be selected.

[0094] The first device 110 may perform handover preparation to the selected (multiple) fourth device 240. Specifically, if intra-CU handover is to be performed, for example, if (multiple) fourth device 140 is selected as (multiple) target fourth device 240, the first device 110 may transmit a UE context establishment request to the (multiple) fourth device 240 to exchange the context of the (multiple) third device 130. If the first device 110 selects (multiple) fourth device 240 for more than one third device 130, a group UE context establishment request may be transmitted to the (multiple) fourth device 240. In some examples, the triggered handover may be a conditional handover (CHO). In this case, the UE context establishment request to the (multiple) fourth device 240 may be a conditional UE context establishment request. The (multiple) fourth device 240 may transmit a UE context establishment response (e.g., a group UE context establishment response) to the first device 110 to confirm the UE context establishment request. The UE context establishment request and the UE context establishment response may be exchanged between the CU 112 of the first device 110 and the DU 141 of the fourth device(s) 140 via the F1 interface.

[0095] In some example embodiments, if an inter-CU handover is to be performed, or if a static network device such as a gNB or an eNB is selected as the target fourth device 240, a message exchange related to handover preparation may be performed via the Xn interface. Specifically, the first device 110 may transmit a handover request to the fourth device 240 via the Xn interface to exchange the context of the third device 130. The fourth device 240 may provide a resource allocation decision signaled in a handover request confirmation.

[0096] In the case where the fourth device(s) 240 are selected and prepared, at 225, the first device 110 may transmit the handover information to the second device 120. In some example embodiments, the handover information may be transmitted in a group UE context modification request (e.g., an RRCReconfiguration message) including the identity of the fourth device(s) 240. The identity of the fourth device(s) 240 may include the cell identity of the fourth device(s) 240. The handover information may be transmitted from the CU 112 of the first device 110 to the DU 121 of the second device 120, for example, via an F1AP procedure.

[0097] After receiving 230 the handover information from the first device 110, the second device 120 may transmit 232 reconfiguration information to the (multiple) third device 130 to configure the (multiple) third device 130 to perform a handover from the second device 120 to the (multiple) fourth device 240. In some example embodiments, the reconfiguration information may include an RRCReconfiguration message for the handover. In some example embodiments, the reconfiguration information is for CHO and may include an RRCReconfiguration message for CHO. The reconfiguration information may include an identity of the (multiple) fourth device 240, such as a cell identity of the (multiple) fourth device 240. By receiving 234 the reconfiguration information from the second device 120, the (multiple) third device 130 may be reconfigured to initiate a handover.

[0098] In some example embodiments, there may be a HO cause information element (IE) provided to the third device (s) 130, i.e., this is a HO caused by the second device, such as an IAB caused HO. The HO IE may be included in the reconfiguration information transmitted by the second device 120 to the third device (s) 130. Based on the HO IE, the third device (s) 130 may determine that the HO is triggered by the second device 120 due to the unavailability of its service, rather than by the measurement report (s) sent by the third device (s) 130.

[0099] In some example embodiments, second device 120 may also transmit a response to the handover information from first device 110. For example, the response may include a group UE context modification response.

[0100] At 235, the second device 120 may become unavailable, for example, due to mobility, failure, deactivation or shutdown of its (multiple) serving cells, or reduce its transmission power when it is replaced by (multiple) fourth devices 240. In the case of CHO, the service unavailability of the second device 120 can achieve the fulfillment of the handover condition at the (multiple) third device 130. The (multiple) third device 130 determines 245 whether the handover condition about the fourth device 240 is satisfied. If the handover condition about the fourth device 240 is satisfied, the (multiple) third device 130 performs 250 a handover from the second device 120 to the fourth device 230. In other examples besides the CHO case, the (multiple) third device 130 can directly perform the handover upon receiving the handover information without monitoring the handover condition. The handover process can involve the (multiple) third device 130, the second device 120, the first device 110, and the fourth device 240.

[0101] In some example embodiments, for the third device 130, if more than one fourth device 240 is prepared for its switching, the third device 130 may perform CHO to determine which device to move to. Thus, different third devices 130 may select different fourth devices 240 to perform the switching. At 250, the third device 130 may monitor multiple conditions, and the first satisfied CHO condition may determine which fourth device 240 the third device 130 will perform the switching process with. Such an embodiment will reserve resources in several fourth devices 240, including their DU and CU portions. Thus, completion of the switching process may trigger the cleanup of the now-abandoned CHO conditions in the third device 130 and the switching preparations in the remaining (multiple) fourth devices 240.

[0102] In some scenarios, if the handover of a large number of third devices 130 is triggered and executed almost at the same time, the signaling storm generated by the handover request of a large number of third devices 130 may cause network overload. In some example embodiments, it is expected that the satisfaction of the handover condition of the third device 130 is dispersed over time. This can be achieved by gradually reducing the transmission power of the second device 120, which can gradually trigger the satisfaction of the handover condition configured for the third device 130 over a relatively long period of time. In some other examples, if the second device 120 (and potential child nodes in the hierarchical structure based on IAB) provides multiple serving cells, it can turn off its serving cells one by one, which can trigger the satisfaction of the handover conditions of different subsets of the third devices 130 in the serving cells one by one. By extending the time period for triggering the satisfaction of the handover condition, the second device 120 can maintain activity to serve some third devices 130 (for example, third devices 130 located around the second device 120 when the second device 120 is away from its previous position). When the second device 120 moves out of a specific range, the handover condition of the served third device 130 is satisfied. Therefore, it alleviates the signaling storm of the second device 120 and the switching interruption time of the third device 130.

[0103] Note that this switching mechanism can still be considered different from traditional switching because the (multiple) fourth device 240 is already prepared in advance. In some example embodiments, in the case where the second device 120 is ramping down the Tx power, the (multiple) target fourth device can ramp up its Tx power. Here, the fourth device can be a new device that can ramp up the Tx power or an existing device that operates below the maximum allowed Tx power. In this case, some coordination may be required to synchronize the second device 120 and the (multiple) fourth device 240, where such coordination can be performed via the F1 interface or the Xn interface. In some example embodiments, in the case where the second device 120 is to be deactivated, the second device 120 can be disabled for a new third device (e.g., UE).

[0104] In some example embodiments, as an alternative to mitigating potential signaling storms, or in addition, the first device 110 may control the handover preparation of different subsets of the third device 130. For example, if the first device 110 selects multiple groups of fourth devices 240 for different subsets of the third device 130, the handover preparation of the fourth device 240 may be performed multiple times for different groups of fourth devices 240, and as a result, the reconfiguration information may be transmitted multiple times toward different subsets of the third device 130. The handover of some subsets of the third device 130 may be delayed to avoid simultaneous execution of the handover process. In some examples, the handover preparation of the fourth device 240 and the following operations may even be performed separately for the third device 130 to cause the third device 130 to perform the handover process one by one.

[0105] It should be understood that the various types of indication information described herein can be used as additional event triggers for switching. That is, during operation, the first device 110 can also obtain measurement reports from (multiple) third devices 130 to determine whether switching of (multiple) third devices 130 is required. If one or more measurement reports indicate that the signal strength with the second device 120 is reduced, the switching of (multiple) third devices 130 can also be triggered. Independent of the measurement report indicating the reduction in signal strength with the second device 120, in some example embodiments of the present disclosure, indication information indicating the unavailability of the expected service of the second device 120 can also be used as a triggering event for the switching of (multiple) third devices 130.

[0106] According to the indication information indicating the service unavailability of the second device 120, the semantics of the handover preparation at the first device 110 may be different from the traditional handover based on the measurement report from the (multiple) third device 130. The (multiple) third device 130 may not know that the handover is not based on its measurement report. The (multiple) third device 130 may perform the handover process in the same or similar manner. However, the indication information indicating the service unavailability of the second device 120 may trigger the handover even before the (multiple) third device 130 senses the change in the radio condition with the second device 120. In this way, if the second device 120 is suddenly moved, fails, deactivated and replaced by a new device, the service continuity of the (multiple) third device 130 can be guaranteed.

[0107] Example environment for device replacement

[0108] As described above, in some cases, one or more devices may be configured to replace the second device 120 to serve the third device(s) 130. This may be related to network planning and management. Figure 3 Another example communication environment 100 is shown in which example embodiments of the present disclosure may be implemented. Figure 3 In the example shown, a new device 340 (referred to as the fourth device 340) is activated to replace the second device 120. In this case, one or more third devices 130 served by the second device 120 can be moved to the fourth device 340 (or other available devices). The fourth device 340 may also be an IAB node, which includes a DU 341 and an MT 342, similar to the DU 121 and the MT 122 included in the second device 120. The MT 342 may be connected to the DU 141-1 of the fourth device 140-1 to replace the MT 122 of the second device 120, and the DU 341 may be connected to the CU 112 of the first device 112 to replace the DU 121 of the second device 120.

[0109] Typically, each cell in a communication system is configured to have a physical cell ID (PCI) to distinguish cells on the radio side, for example, based on network planning. PCI has a pseudo-unique value (504 values ​​in LTE and 1008 values ​​in NR), which needs to be reused within the network, and therefore, the same value should not be used for adjacent radio cells. The communication system supports PCI exchange between network devices via the X2 / Xn interface. Based on this exchange, a neighbor relationship table (NRT) / neighboring cell relationship table (NCRT) is established in each network device. In traditional solutions, changes in network planning (e.g., placing new equipment (e.g., IAB nodes)) are usually slow to react to handover scenarios.

[0110] According to some example embodiments of the present disclosure, the fifth device 150 is configured to activate one or more fourth devices (e.g., the fourth device 340) if it is aware of a change in the service availability of the second device 120. In this way, the activated fourth device 340 can be used to replace the second device 120 to serve the (multiple) third device 130. The switching of the (multiple) third device 130 from the second device 120 to the fourth device 340 can be triggered.

[0111] Example signaling flow for device activation and switchover

[0112] To better illustrate such an example embodiment, reference is now made to Figure 4 , Figure 4 The signaling flow 400 of activation of a fourth device and switching of (a plurality of) third devices according to some example embodiments of the present disclosure is shown. For ease of discussion, reference will be made to Figure 3 A signaling flow 400 is described. The signaling flow 400 involves a first device 110, a second device 120, one or more third devices 130 served by the second device 120, a fourth device 340, and a fifth device 150.

[0113] In operation, the fifth device 150 receives 405 indication information indicating a change in the service availability of the second device 120. The indication information may be similar to some indication information reported to the first device 110 to trigger the switch as described above. In some example embodiments, the indication information may include information indicating that the second device 120 is to be moved out of the service area of ​​at least one third device 130, information indicating that the second device 120 is to fail, information indicating that the second device 130 is to be deactivated, and / or other useful information. As described above, part or all of the indication information used by the fifth device 150 may be transmitted 410 from the second device 120 or 415 from the first device 110.

[0114] The fifth device 150 determines 420 whether the second device is to be replaced based on the indication information. In some example embodiments, if the fifth device 150 determines that one or more third devices 130 may be moved from the second device 120 due to a high local network load, the fifth device 150 may also determine that the second device 120 should be set to be unavailable for serving the one or more third devices 130 and that an additional fourth device 340 may be activated to replace the second device 120 to serve (multiple) specific third devices 130.

[0115] If the fifth device 150 determines that the second device 120 becomes unavailable to serve one or more third devices 130, for example, due to movement, failure, deactivation, or other reasons, the fifth device 150 activates 425 the fourth device 340 to replace the second device 120 to serve the third device(s) 130. For example, the fifth device 150 may be configured with a PCI for the fourth device 340. In some example embodiments, although one fourth device 340 is shown, the fifth device 150 may determine two or more fourth devices 340 to replace the second device 120, each of which is configured to serve a subset of the third devices 130.

[0116] In some example embodiments, the fifth device 150 may prepare a list of possible candidate devices for replacing the service device (e.g., a mobile IAB node), and / or may save a location map of available passive candidate devices that can be activated. These devices (e.g., IAB nodes) may be used to provide services in various scenarios, such as when the vehicle is parked (the ignition switch is off and not moving within a certain range), when the rental vehicle is returned, when the manual switch indicates that the vehicle is now serving as an IAB node, the vehicle is close to a location where communication services are needed (this need can be broadcasted over the network or available in an application server), etc. In some other examples, some autonomous driving vehicles may receive a request to activate their services and actively move to a target location where services are needed without a driver. In some examples, the vehicle may notify the fifth device 150 that it is willing to provide communication services, so that the fifth device 50 may add the vehicle to the list of candidate devices that can be activated. Note that although a vehicle is used as an example here, other entities in which an IAB node is integrated may also provide the fifth device 150 with an indication of willingness to provide services.

[0117] In some example embodiments, the fifth device 150 may determine a target fourth device 340 to be activated among the candidate devices based on proximity information between the fourth device 340 and the second device 120. If the fourth device 340 is located near the second device 120, the fifth device 150 may determine to activate the device. In some example embodiments, if (multiple) measurement reports are transmitted from the second device 120, the fifth device 150 may perform a more accurate decision on selecting the fourth device 340 to replace the second device 120.

[0118] If the fourth device 340 is activated, the establishment process may be performed 435 between the first device 110 and the fourth device 140. In this way, the fourth device 340 may be added to the IAB-based hierarchical structure, for example, by connecting its MT 342 to the DU 141-1 of the fourth device 140-1 and connecting the DU 341 to the CU 112 of the first device 110. Therefore, the fourth device 140 may be controlled by the first device 110.

[0119] Still reference Figure 4 In the signaling flow 400 in FIG. 4 , the fifth device 150 causes further indication information to be transmitted to the first device 110 to indicate that the fourth device 340 is to replace the second device 120 to serve the third device(s) 130. The further indication information is used as (at least a part of) the above indication information used by the first device 110 as a triggering event for triggering the switching of the third device(s) 130. The first device 110 receives 440 the further indication information.

[0120] In some example embodiments, the fifth device 150 may transmit 445 additional indication information to the first device 110. In some example embodiments, the first device 110 may receive information about the fourth device 340 during the setup process at 435, or may be notified by the fifth device 150. In some example embodiments, the second device 120 may transmit 450 to the first device 110 additional indication information indicating that the fourth device 340 is to replace the second device 120 to serve the third device(s) 130. In this case, the fifth device 150 may notify the second device 120 of the replacement. Alternatively, the fourth device 340 may transmit 455 additional indication information to the first device 110 after it is activated by the fifth device 150 to replace the second device 120.

[0121] The first device 110 receives 440 further indication information from the fifth device 150, the second device 120 and / or the fourth device 340, and possible other indication information indicating a change in the service availability of the second device 120, to determine whether a handover of the (plural) third device 130 is to be triggered. In the following, the operations at 460, 465, 470, 472, 474, 475, 480, 485 in the signaling flow 400 are similar to Figure 2 The operations at 220, 225, 230, 232, 234, 235, 245 and 250 in the signaling flow 200 are omitted for brevity.

[0122] In some example embodiments, when triggering the handover of the third device(s) 130, a distinction may be made between capacity enhancement and coverage enhancement use cases. In an example embodiment, the second device 120 may be deployed for coverage enhancement. In such a use case, if the service of the second device 120 becomes unavailable, a new device may be deployed, for example, to replace the second device 120 to provide coverage enhancement. For example, the new device (i.e., Figure 3 The fourth device 340 in the example of the fifth device 150 may be activated by the fifth device 150 to replace the second device 120. In this case, when receiving the information indicating the replacement, the first device 110 may determine to switch all third devices 130 served by the second device 120 to the fourth device 340. The third device 130 may not need to provide a measurement report to the first device 110 to determine which fourth device is suitable for switching.

[0123] In an example embodiment, the second device 120 may be deployed for capacity enhancement. Thus, if the service of the second device 120 becomes unavailable or insufficient, some or all of the third devices 130 may be switched to different neighboring cells provided by the fourth device. In this case, the third device 130 may transmit measurement reports to determine which neighboring cells may provide better service for the individual third device 130. The first device 110 may determine different fourth devices for different third devices 130.

[0124] In some example embodiments, fifth device 150 may provide information on how to distinguish between the two use cases to first device 110. In some example embodiments, for example, first device 110 may determine the use case of second device 120 based on one or more measurement reports received from third device 130 during operation of second device 120. Such UE-based ratings of use cases may be considered in first device 110 or fifth device 150 when deciding to activate a device to replace or deactivate a device that is no longer needed.

[0125] Example method implemented at the device

[0126] Figure 5 A flowchart of an example method 500 implemented at a first device according to some example embodiments of the present disclosure is shown. For the purpose of discussion, Figure 1 and Figure 4 The method 500 is described from the perspective of the first device 110 .

[0127] In block 510 , the first device 110 receives indication information indicating a change in service availability of a second device, the second device serving at least one third device.

[0128] In some example embodiments, the indication information includes at least one of: information indicating that the second device is to be moved out of the service area of ​​at least one third device, information indicating that the second device is to fail, information indicating that the second device is to be deactivated, or information indicating that at least one fourth device is configured to replace the second device to serve at least one third device.

[0129] In some example embodiments, the first device 110 receives at least a portion of the indication information from at least one of: a second device, an entity monitoring mobility of an object located in association with the second device, a fifth device configured to manage the second device, and at least one fourth device.

[0130] In block 520 , the first device 110 determines whether handover of at least one third device from the second device is to be triggered based on the indication information.

[0131] In some example embodiments, the first device 110 determines that handover of the at least one third device from the second device is to be triggered based on the indication information independently of a measurement report from the at least one third device.

[0132] At block 530, if handover of the at least one third device is to be triggered, the first device 110 transmits handover information to the second device, the handover information indicating at least one fourth device selected for handover of the at least one third device from the second device. In some example embodiments, if the first device 110 determines that handover of the at least one third device 130 does not need to be triggered, the first device 110 may wait for subsequent indication information to make a handover decision.

[0133] In some example embodiments, the first device 110 selects at least one fourth device from a plurality of candidate devices that is connected to the first device and that is available to serve the at least one third device.

[0134] In some example embodiments, there may be a plurality of third devices. In some example embodiments, the first device 110 selects a plurality of groups of fourth devices for the plurality of third devices, each of the plurality of groups of fourth devices being selected for switching of at least one third device of the plurality of third devices from the second device.

[0135] In some example embodiments, the at least one fourth device comprises a new device activated to replace the second device.

[0136] In some example embodiments, the first device comprises an integrated access and backhaul donor node. In some example embodiments, the second device and the at least one fourth device comprise an integrated access and backhaul node. In some example embodiments, the at least one third device comprises at least one terminal device.

[0137] Figure 6 A flowchart of an example method 600 implemented at a second device according to some example embodiments of the present disclosure is shown. For the purpose of discussion, Figure 1 and Figure 4 The method 600 is described from the perspective of the second device 120.

[0138] At block 610, the second device 120 receives handover information from the first device independently of the measurement report from the at least one third device, the handover information indicating at least one fourth device selected for handover of the at least one third device from the second device, the second device serving the at least one third device. At block 620, the second device 120 transmits reconfiguration information to the at least one third device, the reconfiguration information being used to configure the at least one third device to perform handover from the second device to the at least one fourth device.

[0139] In some example embodiments, the second device 120 transmits indication information to the first device, the indication information comprising at least one of the following: information indicating that the second device is to be moved out of a service area of ​​at least one third device, information indicating that the second device is to fail, or information indicating that the second device is to be deactivated.

[0140] In some example embodiments, the reconfiguration information includes information indicating that the handover is triggered by a change in service availability of the first device. In some example embodiments, the reconfiguration information is for conditional handover.

[0141] In some example embodiments, the at least one third device includes a plurality of third devices. In some example embodiments, the second device 120 gradually reduces the transmission power of the second device to trigger satisfaction of a switching condition configured for the plurality of third devices.

[0142] Figure 7 A flowchart of an example method 700 implemented at a fifth device according to some example embodiments of the present disclosure is shown. For the purpose of discussion, Figure 1 and Figure 4 Method 700 is described from the perspective of the fifth device 150 .

[0143] In block 710, the fifth device 150 receives indication information indicating a change in service availability of a second device, the second device serving at least one third device and being managed by the fifth device. In some example embodiments, the fifth device 150 may receive at least a portion of the indication information from at least one of the first device and the second device. In some example embodiments, the indication information includes at least one of the following: information indicating that the second device is to be moved out of a service area of ​​the at least one third device, information indicating that the first device is to fail, or information indicating that the second device is to be deactivated.

[0144] At block 720, the fifth device 150 determines whether the second device is to be replaced based on the indication information. At block 730, based on the determination that the second device is to be replaced, the fifth device 150 activates the fourth device to replace the second device to serve at least one third device. In some example embodiments, the fifth device 150 determines the fourth device from a plurality of candidate devices based on proximity information between the second device and the fourth device.

[0145] At block 740 , the fifth device 150 causes further indication information to be transmitted to the first device connected to the second device, the further indication information indicating that the fourth device is to replace the second device to serve the at least one third device.

[0146] Example Device

[0147] In some example embodiments, a first device (e.g., first device 110) capable of performing any of the methods 500 may include a component for performing the corresponding operation of the method 500. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module. The first device may be implemented as the first device 110 or included in the first device 110.

[0148] In some example embodiments, the first device includes: a component for receiving indication information indicating a change in service availability of a second device (e.g., implemented as a second device 120 or included in the second device 120), the second device serving at least one third device (e.g., implemented as (multiple) third devices 130 or included in (multiple) third devices 130); a component for determining whether switching of the at least one third device from the second device is to be triggered based on the indication information; and a component for transmitting switching information to the second device based on the determination that switching of the at least one third device is to be triggered, the switching information indicating at least one fourth device (implemented as a fourth device 240 and / or 340 or included in the fourth device 240 and / or 340) selected for switching of the at least one third device from the second device.

[0149] In some example embodiments, the indication information includes at least one of: information indicating that the second device is to be moved out of the service area of ​​at least one third device, information indicating that the second device is to fail, information indicating that the second device is to be deactivated, or information indicating that at least one fourth device is configured to replace the second device to serve at least one third device.

[0150] In some example embodiments, the component for receiving the indication information includes a component for receiving at least a portion of the indication information from at least one of: a second device, an entity monitoring the mobility of an object located in association with the second device, a fifth device configured to manage the second device, and at least one fourth device.

[0151] In some example embodiments, the means for determining handover of the at least one third apparatus comprises means for determining that handover of the at least one third apparatus from the second apparatus is to be triggered based on the indication information independently of a measurement report from the at least one third apparatus.

[0152] In some example embodiments, the first device further comprises means for selecting at least one fourth device from a plurality of candidate devices that is connected to the first device and that is usable to serve the at least one third device.

[0153] In some example embodiments, the at least one third device includes a plurality of third devices. In some example embodiments, the first device further includes a component for selecting a plurality of groups of fourth devices for the plurality of third devices, each group of the plurality of groups of fourth devices being selected for switching of at least one third device in the plurality of third devices from the second device.

[0154] In some example embodiments, the at least one fourth device comprises a new device activated to replace the second device.

[0155] In some example embodiments, the first apparatus comprises an integrated access and backhaul donor node. In some example embodiments, the second apparatus and the at least one fourth device comprise an integrated access and backhaul node. In some example embodiments, the at least one third apparatus comprises at least one terminal device.

[0156] In some example embodiments, the first apparatus further comprises means for performing other operations in some example embodiments of method 500. In some example embodiments, the means comprises at least one processor; and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause execution of the first apparatus.

[0157] In some example embodiments, a second device (e.g., second device 120) capable of performing any of method 600 may include a component for performing the corresponding operation of method 600. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module. The second device may be implemented as second device 120 or included in second device 120.

[0158] In some example embodiments, the second device includes a component for receiving switching information from a first device (e.g., implemented as a first device 110 or included in the first device 110) independently of a measurement report from at least one third device (e.g., implemented as (multiple) third devices 130 or included in (multiple) third devices 130), the switching information indicating at least one fourth device (e.g., implemented as a fourth device 240 and / or 340 or included in the fourth device 240 and / or 340) selected for switching of the at least one third device from the second device, the second device serving the at least one third device; and a component for transmitting reconfiguration information to the at least one third device, the reconfiguration information being used to configure the at least one third device to perform switching from the second device to the at least one fourth device.

[0159] In some example embodiments, the second device further includes a component for transmitting indication information to the first device, the indication information including at least one of the following: information indicating that the second device is to be moved out of a service area of ​​at least one third device, information indicating that the second device is to fail, or information indicating that the second device is to be deactivated.

[0160] In some example embodiments, the at least one third device comprises a plurality of third devices. In some example embodiments, the second device further comprises means for gradually reducing a transmission power of the second device to trigger satisfaction of a switching condition configured for the plurality of third devices.

[0161] In some example embodiments, the reconfiguration information comprises information indicating that the switching is triggered by a change in service availability of the first apparatus. In some example embodiments, the reconfiguration information is for conditional switching.

[0162] In some example embodiments, the first apparatus comprises an integrated access and backhaul donor node. In some example embodiments, the second apparatus and the at least one fourth device comprise an integrated access and backhaul node. In some example embodiments, the at least one third apparatus comprises at least one terminal device.

[0163] In some example embodiments, the second apparatus further comprises means for performing other operations in some example embodiments of method 600. In some example embodiments, the means comprises at least one processor; and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to cause execution of the second apparatus with the at least one processor.

[0164] In some example embodiments, a fifth apparatus (e.g., fifth device 150) capable of performing any of method 700 may include a component for performing the corresponding operation of method 700. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module. The fifth apparatus may be implemented as fifth device 150 or included in fifth device 150.

[0165] In some example embodiments, the fifth device includes a component for receiving indication information indicating a change in service availability of a second device (e.g., implemented as a second device 120 or included in the second device 120), the second device serving at least one third device (e.g., implemented as (multiple) third devices 130 or included in (multiple) third devices 130) and managed by a fifth device (implemented as a fifth device 150 or included in the fifth device 150); a component for determining whether the second device is to be replaced based on the indication information; a component for activating a fourth device (implemented as a fourth device 340 or included in the fourth device 340) to replace the second device to serve at least one third device based on the determination that the second device is to be replaced; and a component for causing additional indication information to be transmitted to a first device (e.g., implemented as a first device 110 or included in the first device 110) connected to the second device, the additional indication information indicating that the fourth device is to replace the second device to serve at least one third device.

[0166] In some example embodiments, the indication information includes at least one of: information indicating that the second device is to be moved out of a service area of ​​at least one third device, information indicating that the second device is to fail, or information indicating that the second device is to be deactivated.

[0167] In some example embodiments, the means for activating the fourth device includes means for determining the fourth device from among a plurality of candidate devices based on proximity information between the second device and the fourth device.

[0168] In some example embodiments, means for receiving the indication information comprises means for receiving at least a portion of the indication information from at least one of the first device and the second device.

[0169] In some example embodiments, the fifth device comprises an operations administration and maintenance (OAM) entity. In some example embodiments, the first device comprises an integrated access and backhaul donor node. In some example embodiments, the second device and the at least one fourth device comprise an integrated access and backhaul node. In some example embodiments, the at least one third device comprises at least one terminal device.

[0170] In some example embodiments, the fifth apparatus further comprises means for performing other operations in some example embodiments of method 700. In some example embodiments, the means comprises at least one processor; and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to cause execution of the fifth apparatus together with the at least one processor.

[0171] Example devices and computer-readable media

[0172] Figure 8 800 is a simplified block diagram of a device 800 suitable for implementing an example embodiment of the present disclosure. The device 800 may be provided to implement a communication device, such as Figure 1 , Figure 2 and Figure 3 The first device 110, the second device 120, the third device 130, the fourth device 140, 240 or 340, or the fifth device 150 are shown. As shown, the device 800 includes one or more processors 810, one or more memories 820 coupled to the processor 810, and one or more communication modules 840 coupled to the processor 810.

[0173] The communication module 840 is used for two-way communication. The communication module 840 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interface may represent any interface necessary for communication with other network elements. In some example embodiments, the communication module 840 may include at least one antenna.

[0174] Processor 810 may be of any type suitable for the local technology network, and may include, as non-limiting examples, one or more of a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 800 may have multiple processors, such as application specific integrated circuit chips that are time slaved to a clock synchronized with a main processor.

[0175] The 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, compact disk (CD), digital video disk (DVD), optical disk, laser disk, and other magnetic storage and / or optical storage. Examples of volatile memories include, but are not limited to, random access memory (RAM) 822 and other volatile memories that do not persist during power outages.

[0176] The computer program 830 includes computer executable instructions that are executed by the associated processor 810. The program 830 may be stored in a memory, such as in the ROM 824. The processor 810 may perform any suitable actions and processes by loading the program 830 into the RAM 822.

[0177] The exemplary embodiments of the present disclosure may be implemented by a program 830 so that the device 800 may execute a reference Figure 2 , Figure 4 and Figures 5 to 7 Any process of the present disclosure discussed. The exemplary embodiments of the present disclosure may also be implemented by hardware, or by a combination of software and hardware.

[0178] In some example embodiments, the program 830 may be tangibly embodied in a computer-readable medium that may be included in the device 800 (such as in the memory 820) or in other storage devices accessible to the device 800. The device 800 may load the program 830 from the computer-readable medium to the 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. Fig. 9 An example of a computer readable medium 900 is shown which may be in the form of a CD, DVD or other optical storage disk. The computer readable medium has a program 830 stored thereon.

[0179] Generally, various embodiments of the present disclosure may be implemented using hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented using hardware, while other aspects may be implemented using firmware or software that may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure are illustrated and described as block diagrams, flow charts, or using some other graphical representations, it should be understood that, as non-limiting examples, the blocks, devices, systems, techniques, or methods described herein may be implemented using hardware, software, firmware, dedicated circuits or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0180] The present 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, which are executed in a device on a target physical or virtual processor to perform the above referenced Figure 2 , Figure 4 and Figures 5 to 7 Any method described herein. Typically, a program module includes a routine, program, library, object, class, component, data structure, etc. that performs a specific task or implements a specific abstract data type. In various embodiments, the functions of the program modules can be combined or split between program modules as needed. The machine executable instructions of the program modules can be executed in a local or distributed device. In a distributed device, the program modules can be located in both local and remote storage media.

[0181] The program code for executing the disclosed method can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device so that the program code causes the function / operation specified in the flow chart and / or block diagram to be realized when executed by the processor or controller. The program code can be executed completely on the machine, partially on the machine, as an independent software package, partially on the machine and partially on a remote machine, or completely on a remote machine or server.

[0182] In the context of the present disclosure, computer program codes or related data may be carried by any suitable carrier to enable a device, apparatus or processor to perform various processes and operations as described above. Examples of carriers include signals, computer readable media, etc.

[0183] The computer readable medium can be a computer readable signal medium or a computer readable storage medium. The computer readable medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. A more specific example of a computer readable storage medium will include an electrical connection with one or more wires, a portable computer floppy disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0184] In addition, although the operations are described in a particular order, this should not be understood as requiring such operations to be performed in the particular order shown or in order or performing all the operations shown to obtain the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be interpreted as limitations on the scope of the present disclosure, but rather descriptions of features that may be specific to a particular embodiment. Certain features described in the context of a separate embodiment may also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination.

[0185] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it should be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Instead, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A first device, comprising: at least one processor; as well as at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the first device to: receiving indication information, the indication information indicating a change in service availability of a second device, the second device serving at least one third device; wherein the indication information is received from a fifth device configured to manage the first device and the second device; determining whether switching of the at least one third device from the second device is to be triggered based on the indication information; as well as transmitting, in response to determining that the switching of the at least one third device is to be triggered, switching information to the second device, the switching information indicating at least one fourth device selected for the switching of the at least one third device from the second device, wherein the at least one fourth device comprises a new device activated by the fifth device to replace the second device; wherein the at least one third device includes a plurality of third devices, the first device further selects a plurality of groups of fourth devices for the plurality of third devices, each group of the plurality of groups of fourth devices being selected for switching of at least one third device among the plurality of third devices from the second device; and The first device transmits a switching request to the plurality of groups of fourth devices to exchange contexts of the plurality of third devices; The first device comprises an integrated access and backhaul donor node, the second device and the at least one fourth device comprise an integrated access and backhaul node, the at least one third device comprises at least one terminal device, and the fifth device comprises an operation management and maintenance entity or a core network entity.

2. The first device according to claim 1, wherein the indication information comprises at least one of the following: information indicating that the second device is to move out of the service area of ​​the at least one third device, information indicating that the second device is about to fail, information indicating that the second device is to be deactivated, or Information indicating that the at least one fourth device is configured to replace the second device to serve the at least one third device.

3. The first device according to claim 1, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the first device to further receive the indication information in the following manner: At least a portion of the indication information is received from at least one of the following: the second device, an entity monitoring the mobility of an object located in association with the second device, and The at least one fourth device.

4. The first device of claim 1 , wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the first device to determine the switching of the at least one third device by: Independently of the measurement report from the at least one third device, it is determined based on the indication information that handover of the at least one third device from the second device is to be triggered.

5. The first device of claim 1 , wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the first device to: At least one fourth device connected to the first device and available to serve the at least one third device is selected from a plurality of candidate devices.

6. A second device, comprising: at least one processor; as well as at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the second device to: receiving, from the first device, handover information independently of the measurement report from at least one third device, the handover information indicating at least one fourth device selected for handover of the at least one third device from the second device, the second device serving the at least one third device; as well as transmitting reconfiguration information to the at least one third device, the reconfiguration information being used to configure the at least one third device to perform a switch from the second device to the at least one fourth device, wherein the at least one fourth device comprises a new device activated by a fifth device to replace the second device, and the fifth device is used to manage the first device and the second device; The at least one third device includes a plurality of third devices, the switching information indicates selecting a plurality of groups of fourth devices for the plurality of third devices, and each group of the plurality of groups of fourth devices is selected for switching of at least one third device among the plurality of third devices from the second device; wherein the second device is also caused to gradually reduce the transmission power of the second device to trigger the satisfaction of the switching condition configured for the plurality of third devices; wherein the reconfiguration information includes information indicating that the switching is triggered by a change in service availability of the first device, and / or wherein the reconfiguration information is used for conditional switching; The first device comprises an integrated access and backhaul donor node, the second device and the at least one fourth device comprise an integrated access and backhaul node, the at least one third device comprises at least one terminal device, and the fifth device comprises an operation management and maintenance entity or a core network entity.

7. The second device of claim 6, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the second device to: Transmitting indication information to the first device, where the indication information includes at least one of the following: information indicating that the second device is to move out of the service area of ​​the at least one third device, information indicating that the second device is about to fail, or Information indicating that the second device is to be deactivated.

8. A method comprising: receiving, at a first device, indication information indicating a change in service availability of a second device, the second device serving at least one third device; wherein the indication information is received from a fifth device configured to manage the first device and the second device; determining whether switching of the at least one third device from the second device is to be triggered based on the indication information; as well as transmitting, in response to determining that the switching of the at least one third device is to be triggered, switching information to the second device, the switching information indicating at least one fourth device selected for the switching of the at least one third device from the second device, wherein the at least one fourth device comprises a new device activated by the fifth device to replace the second device; The method further comprises: wherein the at least one third device comprises a plurality of third devices, the first device selects a plurality of groups of fourth devices for the plurality of third devices, each group of the plurality of groups of fourth devices is selected for switching at least one third device of the plurality of third devices from the second device; and the first device transmits a switching request to the plurality of groups of fourth devices to exchange contexts of the plurality of third devices; The first device comprises an integrated access and backhaul donor node, the second device and the at least one fourth device comprise an integrated access and backhaul node, the at least one third device comprises at least one terminal device, and the fifth device comprises an operation management and maintenance entity or a core network entity.

9. The method according to claim 8, wherein the indication information comprises at least one of the following: information indicating that the second device is to move out of the service area of ​​the at least one third device, information indicating that the second device is about to fail, information indicating that the second device is to be deactivated, or Information indicating that the at least one fourth device is configured to replace the second device to serve the at least one third device.

10. The method according to claim 8, wherein receiving the indication information comprises: At least a portion of the indication information is received from at least one of the following: the second device, an entity monitoring the mobility of an object located in association with the second device, and The at least one fourth device.

11. The method according to claim 8, wherein determining the switching of the at least one third device comprises: Independently of the measurement report from the at least one third device, it is determined based on the indication information that handover of the at least one third device from the second device is to be triggered.

12. A method comprising: receiving, at the second device, from the first device, handover information independently of the measurement report from at least one third device, the handover information indicating at least one fourth device selected for handover of the at least one third device from the second device, the second device serving the at least one third device; as well as transmitting reconfiguration information to the at least one third device, the reconfiguration information being used to configure the at least one third device to perform a switch from the second device to the at least one fourth device, wherein the at least one fourth device comprises a new device activated by a fifth device to replace the second device, and the fifth device is used to manage the first device and the second device; The at least one third device includes a plurality of third devices, the switching information indicates selecting a plurality of groups of fourth devices for the plurality of third devices, and each group of the plurality of groups of fourth devices is selected for switching of at least one third device among the plurality of third devices from the second device; The method further comprises: gradually reducing the transmission power of the second device to trigger the satisfaction of a switching condition configured for the plurality of third devices; wherein the reconfiguration information includes information indicating that the switching is triggered by a change in the service availability of the first device, and / or wherein the reconfiguration information is used for conditional switching; The first device comprises an integrated access and backhaul donor node, the second device and the at least one fourth device comprise an integrated access and backhaul node, the at least one third device comprises at least one terminal device, and the fifth device comprises an operation management and maintenance entity or a core network entity.

13. The method according to claim 12, further comprising: Transmitting indication information to the first device, where the indication information includes at least one of the following: information indicating that the second device is to move out of the service area of ​​the at least one third device, information indicating that the second device is about to fail, or Information indicating that the second device is to be deactivated.

14. A first device, comprising: means for receiving indication information indicating a change in service availability of a second device, the second device serving at least one third device; means for determining whether switching of the at least one third device from the second device is to be triggered based on the indication information; as well as means for transmitting switching information to the second device in response to determining that the switching of the at least one third device is to be triggered, the switching information indicating at least one fourth device selected for the switching of the at least one third device from the second device; The component for receiving the indication information comprises a component for receiving the indication information from a fifth device configured to manage the first device and the second device; wherein the at least one fourth device comprises a new device activated by the fifth device to replace the second device; The at least one third device includes a plurality of third devices, and the first device further includes: means for selecting a plurality of groups of fourth devices for the plurality of third devices, each of the plurality of groups of fourth devices being selected for switching of at least one third device of the plurality of third devices from a second device; and The first device transmits a switching request to the plurality of groups of fourth devices to exchange contexts of the plurality of third devices; The first device comprises an integrated access and backhaul donor node, the second device and the at least one fourth device comprise an integrated access and backhaul node, the at least one third device comprises at least one terminal device, and the fifth device comprises an operation management and maintenance entity or a core network entity.

15. A second device, comprising: means for receiving handover information from a first device independently of a measurement report from at least one third device, the handover information indicating at least one fourth device selected for handover of the at least one third device from the second device, the second device serving the at least one third device; as well as means for transmitting reconfiguration information to the at least one third device, the reconfiguration information being used to configure the at least one third device to perform a switch from the second device to the at least one fourth device, wherein the at least one fourth device comprises a new device activated by a fifth device to replace the second device, the fifth device being used to manage the first device and the second device; wherein the at least one third device includes a plurality of third devices, the switching information indicates selecting a plurality of groups of fourth devices for the plurality of third devices, and each group of the plurality of groups of fourth devices is selected for switching of at least one third device among the plurality of third devices from the second device; The second device further comprises means for gradually reducing the transmission power of the second device to trigger satisfaction of a switching condition configured for the plurality of third devices; wherein the reconfiguration information includes information indicating that the switching is triggered by a change in service availability of the first device, and / or wherein the reconfiguration information is used for conditional switching; The first device comprises an integrated access and backhaul donor node, the second device and the at least one fourth device comprise an integrated access and backhaul node, the at least one third device comprises at least one terminal device, and the fifth device comprises an operation management and maintenance entity or a core network entity.

16. A computer-readable medium comprising instructions for causing an apparatus to at least perform the method according to any one of claims 8 to 11, or the method according to any one of claims 12 to 13.

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