Methods, apparatus, and computer-readable media for integrated access and backhaul communications

Abstract

Embodiments of the present disclosure relate to methods, devices, and computer-readable storage media for integrated access and backhaul (IAB) communications. According to embodiments of the present disclosure, a first IAB donor receives a reconfiguration message for a terminal device in a service cell served by an IAB node from a second IAB donor. The IAB node migrates from a first cell communicating with the first IAB donor to a second cell communicating with the second IAB donor, while keeping the cell identifier of the service cell unchanged. The reconfiguration message instructs the terminal device to update the configuration of the second IAB donor. The first IAB donor encrypts the reconfiguration message based on the security parameters of the first IAB donor, and provides the encrypted reconfiguration message to the IAB node. This solution enables the physical cell identifier of the cell provided by the IAB node to remain unchanged during the migration of the IAB node.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to the field of telecommunications, and in particular to methods, apparatus, and computer-readable media for integrated access and backhaul (IAB) communications. Background Art

[0002] IAB has been introduced in Release 16 (Rel-16) of the 3GPP specification as a key enabler for fast and cost-effective deployment. IAB nodes use the same spectrum and air interface for access and backhaul, creating a hierarchical wireless multi-hop network between sites. Each hop ultimately terminates at an IAB donor that is connected to the core network with the help of a conventional fixed backhaul. The IAB node includes a mobile terminal (MT) part and a distributed unit (DU) part, the MT part acting as a user equipment (UE) towards its parent IAB node, and the DU part acting as a base station towards the next hop IAB node. The IAB donor includes a centralized unit (CU) part and a DU part. The IAB DU can provide one or more cells to serve the UE. From the perspective of the UE, the cell provided by the IAB DU can be regarded as a normal cell.

[0003] Because the backhaul connection may fail or the IAB topology or IAB mobility may change, the IAB node may need to change its serving node, which may be located under the same or different (multiple) IAB donors. In the latter case, the physical cell identifier (PCI) of the cell served by the IAB DU may have to change to avoid PCI conflicts due to the mobility of the IAB node. If the PCI of the cell served by the IAB node changes during handover and connection to the new IAB donor, a handover or radio resource control (RRC) re-establishment procedure will be performed in order to reconfigure the (multiple) UEs connected to the IAB node. This may result in connection and service interruption at the UE connected to the IAB node. Summary of the invention

[0004] In general, example embodiments of the present disclosure provide methods, apparatus, and computer-readable media for IAB communications.

[0005] In a first aspect, a method is provided. The method includes receiving, at a first device, from a second device, a reconfiguration message for a fourth device in a serving cell served by a third device, the third device migrating from a first cell communicating with the first device to a second cell communicating with the second device while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message instructing the fourth device to update a configuration for the second device; encrypting the reconfiguration message based on a security parameter of the first device; and providing the encrypted reconfiguration message to the third device.

[0006] In a second aspect, a method is provided. The method includes generating, at a second device, a reconfiguration message for a fourth device in a serving cell served by a third device, the third device migrating from a first cell communicating with a first device to a second cell communicating with a second device while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message instructing the fourth device to update a configuration for the second device; and transmitting the reconfiguration message to the first device.

[0007] In a third aspect, a method is provided. The method includes receiving, at a third device, from a first device or a second device, a reconfiguration message for a fourth device in a serving cell served by the third device, the third device migrating from a first cell communicating with the first device to a second cell communicating with the second device while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message instructing the fourth device to update a configuration for the second device; forwarding the reconfiguration message to the fourth device; and receiving a reconfiguration completion message from the fourth device.

[0008] In a fourth aspect, a method is provided. The method includes receiving a reconfiguration message from a third device at a fourth device, the third device providing a serving cell for serving the fourth device, the third device migrating from a first cell communicating with the first device to a second cell communicating with the second device while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message including a new configuration for the second device; updating a configuration used at the fourth device with the new configuration without performing a random access procedure; and transmitting a reconfiguration completion message to the third device.

[0009] In a fifth aspect, a first device is provided. The first device includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to cause the first device to receive, together with the at least one processor, a reconfiguration message for a fourth device in a serving cell served by a third device from a second device, the third device migrates from a first cell communicating with the first device to a second cell communicating with the second device, while keeping the cell identifier of the serving cell unchanged, and the reconfiguration message indicates that the fourth device updates the configuration for the second device; encrypts the reconfiguration message based on the security parameters of the first device; and provides the encrypted reconfiguration message to the third device.

[0010] In a sixth aspect, a second device is provided. The second device includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to cause the second device, together with the at least one processor, to generate a reconfiguration message for a fourth device in a serving cell served by a third device, the third device migrates from a first cell communicating with the first device to a second cell communicating with the second device, while keeping the cell identifier of the serving cell unchanged, and the reconfiguration message instructs the fourth device to update the configuration for the second device; and transmit the reconfiguration message to the first device.

[0011] In a seventh aspect, a third device is provided. The third device includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to cause the third device to receive a reconfiguration message for a fourth device in a service cell served by the third device from a first device or a second device, the third device migrates from a first cell communicating with the first device to a second cell communicating with the second device, while keeping the cell identifier of the service cell unchanged, and the reconfiguration message indicates that the fourth device updates the configuration for the second device; forwards the reconfiguration message to the fourth device; and receives a reconfiguration completion message from the fourth device.

[0012] In an eighth aspect, a fourth device is provided. The fourth device includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to cause the fourth device to receive a reconfiguration message from a third device together with the at least one processor, the third device provides a serving cell for serving the fourth device, the third device migrates from a first cell communicating with the first device to a second cell communicating with the second device, while keeping the cell identifier of the serving cell unchanged, and the reconfiguration message includes a new configuration for the second device; updating the configuration used at the fourth device with the new configuration without performing a random access procedure; and transmitting a reconfiguration completion message to the third device.

[0013] In a ninth aspect, an apparatus is provided. The apparatus includes a component for receiving a reconfiguration message for a fourth device in a serving cell served by a third device from a second device, the third device migrating from a first cell communicating with the apparatus to a second cell communicating with the second device while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message instructing the fourth device to update a configuration for the second device; a component for encrypting the reconfiguration message based on a security parameter of the apparatus; and a component for providing the encrypted reconfiguration message to the third device.

[0014] In a tenth aspect, an apparatus is provided. The apparatus includes a component for generating a reconfiguration message for a fourth device in a serving cell served by a third device, the third device migrating from a first cell communicating with a first device to a second cell communicating with the apparatus while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message instructing the fourth device to update a configuration for the apparatus; and a component for transmitting the reconfiguration message to the first device.

[0015] In an eleventh aspect, an apparatus is provided. The apparatus includes a component for receiving a reconfiguration message for a fourth device in a serving cell served by the apparatus from a first device or a second device, the third device migrates from a first cell communicating with the first device to a second cell communicating with the second device while keeping the cell identifier of the serving cell unchanged, and the reconfiguration message indicates that the fourth device updates the configuration for the second device; a component for forwarding the reconfiguration message to the fourth device; and a component for receiving a reconfiguration completion message from the fourth device.

[0016] In a twelfth aspect, an apparatus is provided. The apparatus includes a component for receiving a reconfiguration message from a third device, the third device providing a serving cell for serving the apparatus, the third device migrating from a first cell communicating with a first device to a second cell communicating with a second device while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message including a new configuration for the second device; a component for updating a configuration used at the apparatus with the new configuration without performing a random access procedure; and a component for transmitting a reconfiguration completion message to the third device.

[0017] In a thirteenth aspect, a computer program product is provided, the computer program product being stored on a computer readable medium and comprising machine executable instructions, wherein when the machine executable instructions are executed, the machine executes the method according to the first aspect, the second aspect, the third aspect or the fourth aspect.

[0018] In a fourteenth aspect, a computer-readable storage medium is provided, the computer-readable storage medium comprising program instructions stored thereon, wherein when the instructions are executed by a device, the device causes the device to execute the method according to the first aspect, the second aspect, the third aspect or the fourth aspect.

[0019] 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

[0020] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of some example embodiments of the present disclosure in the accompanying drawings, in which:

[0021] Figure 1 A block diagram of a system for IAB communications is shown;

[0022] 2a and 2b illustrate an example mobile IAB environment in which embodiments of the present disclosure may be implemented;

[0023] Figure 3 A schematic diagram showing interactions between devices according to some example embodiments of the present disclosure;

[0024] Figure 4 A schematic diagram showing interactions between devices according to some example embodiments of the present disclosure;

[0025] Figure 5 A schematic diagram showing interactions between devices according to some example embodiments of the present disclosure;

[0026] Figure 6 A flowchart illustrating an example method for IAB communications according to some example embodiments of the present disclosure is shown;

[0027] Figure 7 A flowchart illustrating an example method for IAB communications according to some example embodiments of the present disclosure is shown;

[0028] Figure 8 A flowchart illustrating an example method for IAB communications according to some example embodiments of the present disclosure is shown;

[0029] Fig. 9 A flowchart illustrating an example method for IAB communications according to some example embodiments of the present disclosure is shown;

[0030] Fig.10 shows a simplified block diagram of an apparatus suitable for implementing an embodiment of the present disclosure; and

[0031] Fig.11 A block diagram of an example computer-readable medium is shown according to some example embodiments of the present disclosure.

[0032] Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0033] The principle 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 disclosure described herein can be implemented in various other ways except the way described below.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] As used in this application, the term "circuitry" may refer to one, more, or all of the following:

[0039] (a) a pure hardware circuit implementation (such as an implementation using only analog and / or digital circuitry), and

[0040] (b) a combination of hardware circuitry and software such as (where applicable):

[0041] (i) a combination of analog and / or digital hardware circuits and software / firmware, and

[0042] (ii) any portion of a hardware processor(s) with software, including digital signal processor(s), software and memory(s), which work together to cause a device (such as a mobile phone or server) to perform various functions, and

[0043] (c) Hardware circuit(s) and / or processor(s), such as microprocessor(s) or portion(s) of microprocessor(s), which requires software (e.g., firmware)

[0044] The software can be saved when no operation is needed.

[0045] 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.

[0046] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard, such as 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), New Radio (NR), 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.

[0047] 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 NodeB (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, a low-power node (such as a femto, a micro, etc.), depending on the terminology and technology applied. In the following description, the terms "network device", "BS" and "node" may be used interchangeably.

[0048] 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. In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

[0049] Although the functions described herein may be performed in fixed and / or wireless network nodes in various example embodiments, in other example embodiments, the functions may be implemented in a user equipment device (such as a mobile phone or tablet or laptop or desktop or mobile IOT device or fixed IOT device). For example, the user equipment device may be appropriately equipped with corresponding capabilities as described in conjunction with (multiple) fixed and / or wireless network nodes. The user equipment device may be a user device and / or a control device, such as a chipset or a processor, which is configured to control the user device when installed in the user device. Examples of such functions include boot server functions and / or home subscriber servers, which may be implemented in the user equipment device by providing the user equipment device with software configured to cause the user equipment device to execute from the perspective of these functions / nodes.

[0050] Example embodiments of the present disclosure relate to a radio access network with a wireless backhaul of an access point. The backhaul link from the access node to the wired portion of the network and the core network is dynamically reconfigured with little impact on the user's terminal device. The backhaul can be multi-hop or meshed. An important application of an embodiment of the present disclosure is for IAB communications in a 3GPP IAB network with terminal devices, IAB nodes, and wired IAB donor nodes. In the following, embodiments of the present disclosure will be described with reference to a 3GPP IAB network. It should be understood that embodiments of the present disclosure may also be applied to any other network with a wireless backhaul.

[0051] Figure 1 1 shows a block diagram of a system 100 for IAB communication. Figure 1 As shown, system 100 includes core network 110, IAB donor 120, IAB nodes 130-1 and 130-2 (collectively referred to as "IAB nodes 130" or individually referred to as "IAB nodes 130"), network devices 140 (such as gNBs), and UEs 150-1, 150-2, and 150-3 (collectively referred to as "UE 150" or individually referred to as "UE 150"). In this document, the terms "IAB nodes" and "IAB devices" may be used interchangeably. The terms "IAB donor nodes", "IAB donors", and "IAB donor devices" may be used interchangeably.

[0052] The core network 110 may include many network entities that provide different network functions, for example, a network slice selection function (NSSF) 111, a unified data repository (UDM) 112, an access and mobility management function (AMF) 113, a network function (NF) repository function (NRF), a session management function (SMF), a policy control function (PCF), a network exposure function (NEF), etc.

[0053] The IAB donor 120 may include a centralized unit (CU) 121 (also referred to as "IAB donor CU 121") and a distributed unit (DU) 122 (also referred to as "IAB donor DU 122"). The IAB node 130-1 may include an MT portion 131-1 and a DU 132-1. The IAB node 130-2 may include an MT portion 131-2 and a DU 132-2. The MTs 131-1 and 131-2 may also be collectively referred to as "IAB MTs 131" or individually as "IAB MTs 131". The DUs 132-1 and 132-2 may also be collectively referred to as "IAB DUs 132" or individually as "IAB DUs 132".

[0054] The IAB donor DU 122 or each IAB DU 132 may provide one or more cells to serve the UE. For example, the cells provided by the DU may broadcast normal control signals, such as synchronization signal blocks (SSBs) for downlink synchronization, and system information. Therefore, from the perspective of the UE, the cells provided by the DU may be regarded as normal cells. For example, Figure 1 As shown, IAB donor DU 122 serves UE 150-1, IAB DU 132-1 serves UE 150-2, and IAB DU 132-2 serves UE 150-3.

[0055] The IAB MT 131 of the IAB node 130 may act as a UE towards its parent node. For example, the IAB MT 131-1 may act as a UE towards the IAB donor node 120 (i.e., the IAB donor DU 122), and the IAB MT 131-2 may act as a UE towards the IAB node 130-1 (i.e., the IAB DU 132-1). On the sublink, the IAB DU 132 of the IAB node 130 may act as a network device (such as a gNB) towards its next-hop IAB node. For example, the IAB donor DU 122 may act as a gNB towards the IAB node 130-1, and the IAB DU 132-1 may act as a gNB towards the IAB node 130-2. On the access link, as described above, the IAB donor 120 and the IAB node 130 may act as normal gNBs to provide a wireless interface for the UE 150 in its coverage area.

[0056] In the environment 100, each IAB MT 132 may have an RRC connection with the IAB donor CU 121 and a non-access stratum (NAS) connection with the AMF 113. Each IAB node 130 (i.e., IAB DU 132) maintains an F1 interface to the IAB donor 120 (i.e., IAB donor CU 121). Therefore, it can be inferred that the IAB node 130 has both an access node function (by means of the IAB DU 132 having an F1 interface to the IAB donor CU 121) and a UE function (by means of the IAB MT 131 having an RRC connection to the IAB donor CU 121 and a NAS connection to the AMF 113).

[0057] Communications in environment 100 may be implemented according to any (multiple) appropriate communications protocols, including but not limited to cellular communications protocols such as first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), and fifth generation (5G), wireless local network communications protocols such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, and / or any other protocols currently known or to be developed in the future. In addition, communications may utilize any appropriate wireless communications 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 multiple access (OFDMA), and / or any other technology currently known or to be developed in the future.

[0058] An IAB node may need to change its serving node because the backhaul (BH) connection may fail or the IAB topology or IAB mobility may change. This change in backhaul topology may involve a change of the parent IAB node of the IAB node or even the IAB donor. In the former case, the cell configuration is maintained and the change is transparent to the UE served by the IAB node. In the latter case, the cell configuration will be adapted by the new IAB donor, for example, the security context may change. This situation is particularly applicable to mobile IAB nodes, where the BH changes frequently and the IAB donor may change at some point.

[0059] IAB nodes may have different implementation options or operating modes. For example, an IAB node may be installed on a fixed infrastructure (e.g., a lamp post or street furniture). Such an IAB node may be referred to as a fixed IAB node. Depending on the channel conditions on the wireless backhaul, a fixed IAB node may migrate from one donor IAB node to an adjacent donor IAB node. Another IAB node implementation may be a situation where the IAB node is installed on a vehicle and the IAB node is active (i.e., serving UEs), in which case the IAB is static or slowly moving, and in particular serves UEs outside the vehicle. For example, when the vehicle is parked, the IAB node may serve UEs outside the vehicle. When the nomadic IAB is not active (i.e., operable), it may enter an idle mode, for example, similar to RRC idle or RRC inactive. Such an IAB node may be referred to as a nomadic IAB node. Nomadic IAB nodes may be integrated into vehicles such as car-sharing fleets or taxi fleets. Nomadic IAB nodes may be used to provide coverage and / or capacity enhancement. Another concept of IAB (i.e., mobile IAB) has recently been proposed. The mobile IAB node is located on a mobile object (e.g., a vehicle or balloon or drone) and provides wireless access to (multiple) UEs inside or outside the mobile object. In some cases, the UE may be physically attached to the movement of the mobile IAB node (e.g., inside a vehicle carrying the IAB node). In this case, preferably, the UE remains connected to the mobile IAB node.

[0060] 2a and 2b illustrate an example mobile IAB environment 200 in which embodiments of the present disclosure may be implemented. As shown in FIG2a and 2b, the environment 200 includes an IAB donor 210 (hereinafter also referred to as a "first IAB donor"), an IAB donor 220 (hereinafter also referred to as a "second IAB donor"), an IAB node 230, and UEs 240-1 and 240-2 (collectively referred to as "UE 240" or individually referred to as "UE 240").

[0061] The IAB donor 210 includes a CU 211 (hereinafter also referred to as "IAB donor CU 211") and a DU 212 (hereinafter also referred to as "IAB donor DU 212"). The IAB donor 220 includes a CU 221 (hereinafter also referred to as "IAB donor CU 221") and a DU 222 (hereinafter also referred to as "IAB donor DU 222"). The IAB node 230 includes an MT 231 (hereinafter also referred to as "IAB MT 231") and a DU 232 (hereinafter also referred to as "IAB DU 232"). The IAB donor DU 212 may provide a cell 250-1, and the IAB donor DU 222 may provide a cell 250-2. An Xn interface 270 exists between the IAB donor CU 211 and the IAB donor CU 221. Herein, the Xn interface 270 may also be referred to as a "third interface".

[0062] Initially, as shown in FIG. 2a , the IAB node 230 may be located in a cell 250-1 (hereinafter also referred to as a “first cell”) and served by the IAB donor 210. An F1 interface 280 may be established between the IAB donor CU 211 and the IAB DU 232. The F1 interface 280 may also be referred to as a “first interface” herein. The IAB DU 232 may provide cells 260-1 and 260-2 to serve the UE 240. For example, the PCI of the cell 260-1 may be X, and the PCI of the cell 260-2 may be Y.

[0063] 2b, IAB node 230 may move out of cell 250-1 and into cell 250-2 (hereinafter also referred to as "second cell"). This may trigger a BH change from old cell 250-1 to target cell 250-2 provided by IAB donor DU 222.

[0064] Conventionally, in this case, the PCI of the cells 260-1 and 260-2 provided by the IAB DU 232 needs to be changed to avoid PCI conflicts due to the movement of the IAB node 230. However, if the PCI of the cells 260-1 and 260-2 served by the IAB DU 232 is changed during handover and connection to the IAB donor 220, a handover or RRC reestablishment procedure will be used in order to reconfigure the UE 240 connected to the IAB node 230. This may cause a connection and service interruption at the UE 240 connected to the IAB node 230.

[0065] Embodiments of the present disclosure provide a solution for IAB communication to solve the above problems and one or more other potential problems. The solution enables the PCI of the cell provided by the migration IAB node to remain unchanged. In this way, the solution can minimize the impact on the UE served by the migration IAB node during the inter-donor topology adaptation, because the RRC connection to the cell will be maintained and no connection interruption will occur at the UE. In addition, the solution can minimize the signaling required on the radio interface.

[0066] 2b, the target IAB donor CU (e.g., IAB donor CU 221) may generate an RRC reconfiguration message (with or without synchronization). The RRC reconfiguration message may be sent to the UE 240 by the target donor CU (CU 221) or by the source IAB donor CU (e.g., IAB donor CU 211) via the IAB DU 232. The reconfiguration message generated by the IAB donor CU 221 may include a new security configuration of the IAB donor CU 221 to be used after the reconfiguration.

[0067] If the RRC reconfiguration message is sent from the IAB donor CU 211 to the UE 240, the RRC reconfiguration message may be provided by the target donor CU 221 to the IAB donor CU 211 via the third interface 270 and encrypted by the IAB donor CU 211. Then, before the IAB node 230 changes the link of its MT 231, the RRC message may be sent from the IAB donor CU 211 to the IAB node 230 via the F1 interface 280.

[0068] If the RRC reconfiguration message is sent from the IAB donor CU 221 to the UE 240, the RRC reconfiguration message may be generated once the F1 interface 290 between the IAB DU 232 and the IAB donor CU 221 is established and the cells 260-1 and 260-2 are actively running under the IAB donor CU 221. The F1 interface 290 may also be referred to herein as a "second interface".

[0069] If the RRC reconfiguration message is sent from the IAB donor CU 221 to the UE 240, the IAB donor CU 221 may request the IAB donor CU 211 to encrypt the RRC reconfiguration message based on its security parameters and send the encrypted RRC reconfiguration message back to the IAB donor CU 221 so that the UE 240 will be able to decrypt the message. Once the RRC connection from the migration IAB node 230 (i.e., the IAB MT 231) to the IAB donor 220 is established and the F1 interface 290 between the IAB DU 232 and the IAB donor CU 221 is established, the IAB node 230 may send the RRC reconfiguration message to the UE 240 connected to the IAB node 230.

[0070] Even after the reconfiguration, the UE 240 connected to the IAB node 230 may remain connected to the same cells 260-1 and 260-2 of the IAB node 230 because the PCIs of the cells 260-1 and 260-2 have not changed. Since the UE 240 is still synchronized with the same cell, the UE 240 may not need a random access procedure. The IAB donor CU 221 does not have to reserve access resources (e.g., for a contention-free random access procedure) for the cell of the IAB node 230. During the migration of the IAB node 230, the HO procedure of the UE 240 may not be performed. The UE 240 may only need to change the security configuration, i.e., the security key, for use with the target IAB donor CU 221.

[0071] Figure 3 A schematic diagram of interaction 300 between devices according to some example embodiments of the present disclosure is shown. For example, interaction 300 involves UE 240 (such as UE 240-1 or 240-2), IAB node 230, IAB donor 210, and IAB donor 220.

[0072] like Figure 3 As shown, IAB MT 231 transmits 301 a measurement report to IAB donor CU 211, e.g., via RRC signaling. In some example embodiments, the measurement report may be triggered by a configured HO event indicating a better connection quality on an alternative link to IAB donor DU 222 under IAB donor CU 221.

[0073] The IAB donor CU 211 decides 302 to hand over the IAB node 230 (radio connection with the IAB MT 231) to the cell served by the IAB donor 220. The handover process may be a normal handover process or any one of other mobility processes, such as conditional handover (CHO). It should be understood that the scope of the present disclosure is not limited to the selection of the HO process of the IAB MT 231.

[0074] The IAB donor CU 211 transmits 303 a HO request to the IAB donor CU 221. The HO request may be directed not only to the IAB MT 231 but also to the UE 240 connected to the IAB node 230 in the cell served by the IAB DU 232. It should be understood that the migrating IAB node 230 may also have descendants / child nodes, and during the migration process, connections should also be reconfigured for them, which is Figure 3 In some example embodiments, the HO request may include the F1 interface of the IAB donor CU 211 and the context of the UE 240. It should be understood that context transfer may also occur with other signaling (eg, context retrieval) other than the HO request.

[0075] The IAB donor CU 221 performs 304 admission control by evaluating the possibility of accommodating the traffic moving with the IAB node 230. Here, it is assumed that the admission control of the IAB node 230 and the UE 240 is successful.

[0076] The IAB donor CU 221 transmits 305 to the IAB donor CU 211 an acknowledgement of the RRC reconfiguration message including the HO command of the IAB MT 231 and the UE 240. The RRC reconfiguration message may indicate a reconfiguration procedure without synchronization. That is, since the cell(s) served by the IAB DU 232 do not change, the UE 240 will not acquire uplink synchronization by performing a random access procedure.

[0077] The IAB donor CU 211 transmits 306 the HO command to the IAB MT 231. In addition, the IAB donor CU 211 transmits 307 the RRC reconfiguration message of the UE 240 to the IAB DU 232 via F1 application protocol (F1AP) signaling. In some example embodiments, the IAB donor CU 211 may also indicate that the F1 and UE contexts should be maintained even if a new F1 interface with the IAB donor CU 221 is established. In some example embodiments, the IAB node 230 (i.e., the IAB DU 232) may store the RRC reconfiguration message of the UE 240. The IAB node 230 may also store the current cell radio network temporary identifier (C-RNTI) because the UE 240 will continue to monitor the current C-RNTI (s). After the migration of the IAB node 230, the C-RNTI (s) may change or remain unchanged.

[0078] IAB node 230 initiates 308 a HO execution to the target cell (i.e., the cell served by IAB donor DU 222). In some example embodiments, the HO execution may immediately follow the HO command (i.e., a normal HO procedure). Alternatively, if conditional HO is used, the configured CHO trigger may be used to initiate the HO execution.

[0079] The IAB MT 231 accesses 309 the target cell served by the IAB donor DU 222 and establishes an RRC connection to the IAB donor CU 221. The IAB MT 231 transmits 310 a HO complete message to the IAB donor CU 221.

[0080] The F1 setup process is initiated to establish 311 the F1 interface 290 between the IAB DU 232 and the IAB donor CU 221. In some example embodiments, the stored context may be restored (after 307). For example, there may be a separate indication from the IAB DU 232 (which has the stored context) or from the IAB donor CU 221 to restore the stored context if it wants to proceed with the new process.

[0081] Since the cell(s) served by the IAB DU 232 continue to be active, even after the F1 interface 290 with the IAB donor CU 221 is established, the IAB DU 232 transmits 312 an RRC reconfiguration message to the UE 240 using the C-RNTI(s) that the UE 240 is monitoring. Since the encryption of the RRC reconfiguration message has been done using the security parameters of the IAB donor CU 211, the UE 240 will be able to decrypt and decode the message. The RRC reconfiguration message may include a new security configuration that is valid for the connection to the IAB donor CU 221. It should be noted that since the cell / PCI does not change, when the reconfiguration message is sent to the UE 240, the change of the serving CU of the UE 240 is gradual.

[0082] UE 240 transmits 313 an RRC reconfiguration complete message to IAB DU 232, and after UE 240 is controlled by IAB donor CU 221, IAB DU 232 forwards 314 the RRC reconfiguration complete message via F1AP signaling. After successful completion of the process, IAB donor CU 221 may release 315 the context in IAB donor CU 211 and perform path switching for traffic data.

[0083] Figure 4A schematic diagram of an interaction 400 between devices according to some example embodiments of the present disclosure is shown. For example, the interaction 400 involves a UE 240 (such as a UE 240-1 or 240-2), an IAB node 230, an IAB donor 210 (hereinafter also referred to as a "source IAB donor"), and an IAB donor 220 (hereinafter also referred to as a "target IAB donor"). Figure 3 and Figure 4 The main difference between the two is that once the F1 interface between the IAB DU 232 and the IAB donor CU 221 is established, the RRC reconfiguration message of the UE 240 is not sent via the IAB donor CU 211, but is directly sent from the IAB donor CU 221 to the migration IAB DU 232.

[0084] like Figure 4 As shown, IAB MT 231 transmits 401 a measurement report to IAB donor CU 211, for example via RRC signaling. In some example embodiments, the measurement report may be triggered by a configured HO event indicating a better connection quality on an alternative link to IAB donor DU 222 under IAB donor CU 221.

[0085] The IAB donor CU 211 decides 402 to hand over the IAB node 230 (radio connection with the IAB MT 231) to the cell served by the IAB donor 220. The handover process may be a normal handover process or any one of other mobility processes, such as conditional handover (CHO). It should be understood that the scope of the present disclosure is not limited to the selection of the HO process of the IAB MT 231.

[0086] The IAB donor CU 211 transmits 403 a HO request to the IAB donor CU 221. The HO request may be directed not only to the IAB MT 231 but also to the UE 240 connected to the IAB node 230 in the cell served by the IAB DU 232. It should be understood that the migrating IAB node 230 may also have descendants / child nodes, and during the migration process, connections should also be reconfigured for them, which is Figure 4 In some example embodiments, the HO request may include the F1AP interface of the IAB donor CU 211 and the context of the UE 240. It should be understood that context transfer may also occur with other signaling (eg, context retrieval) other than the HO request.

[0087] The IAB donor CU 221 performs 404 admission control by evaluating the possibility of accommodating the traffic moving with the IAB node 230. Here, it is assumed that the admission control of the IAB node 230 and the UE 240 is successful.

[0088] The IAB donor CU 221 transmits 405 to the IAB donor CU 211 an acknowledgement of the HO command of the IAB MT 231 and the RRC reconfiguration message of the UE 240. In some embodiments, the HO command and the RRC reconfiguration may be transmitted in separate messages at different times. The RRC reconfiguration message may indicate a reconfiguration procedure with or without synchronization. If the RRC reconfiguration message indicates a reconfiguration procedure without synchronization, the UE 240 will not acquire uplink synchronization by performing a random access procedure because the cell(s) served by the IAB DU 232 have not changed.

[0089] The IAB donor CU 211 transmits 406 the HO command to the IAB MT 231. In response to receiving 405 the confirmation from the IAB donor CU 221, the IAB donor CU 211 encrypts the RRC reconfiguration message using its own security parameters and transmits 407b the encrypted RRC reconfiguration message back to the IAB donor CU 221. The IAB donor CU 211 may also indicate 407a to the IAB DU 232 via F1AP signaling that the F1 and UE contexts should be maintained even if a new F1 interface with the IAB donor CU 221 is established.

[0090] IAB node 230 initiates 408 a HO execution to the target cell (i.e., the cell served by IAB donor DU 222). In some example embodiments, the HO execution may immediately follow the HO command (i.e., normal HO procedure). Alternatively, if conditional HO is used, the configured CHO trigger may be used to initiate the HO execution.

[0091] The IAB MT 231 accesses 409 the target cell served by the IAB donor DU 222 and establishes an RRC connection to the IAB donor CU 221. The IAB MT 231 transmits 410 a HO complete message to the IAB donor CU 221.

[0092] The F1 establishment process is initiated to establish 411 the F1 interface 290 between the IAB DU 232 and the IAB donor CU 221. Once the F1 interface 290 is established, the IAB donor CU 221 transmits 412 an RRC reconfiguration message directly to the IAB DU 232 via F1AP signaling over the established F1 interface 290.

[0093] Since the cell(s) served by the IAB DU 232 continue to be active, even after the F1 interface 290 with the IAB donor CU 221 is established, the IAB DU 232 transmits 413 an RRC reconfiguration message to the UE 240 using the C-RNTI(s) that the UE 240 is monitoring. Since the encryption of the RRC reconfiguration message has been done using the security parameters of the IAB donor CU 211, the UE 240 will be able to decrypt and decode the message. The RRC reconfiguration message may include a new security configuration that is valid for the connection to the IAB donor CU 221. It should be noted that since the cell / PCI does not change, the change of the serving CU of the UE 240 is gradual when the reconfiguration message is sent to the UE 240.

[0094] UE 240 transmits 414 an RRC reconfiguration complete message to IAB DU 232, and after UE 240 is controlled by IAB donor CU 221, IAB DU 232 forwards 415 the RRC reconfiguration complete message via F1AP signaling. After successful completion of the process, IAB donor CU 221 may release 416 the context in IAB donor CU 211 and perform path switching for traffic data.

[0095] Figure 5 A schematic diagram of an interaction 500 between devices according to some example embodiments of the present disclosure is shown. For example, the interaction 500 involves a UE 240 (such as a UE 240-1 or 240-2), an IAB node 230, an IAB donor 210 (hereinafter also referred to as a "source IAB donor"), and an IAB donor 220 (hereinafter also referred to as a "target IAB donor"). Figure 4 and Figure 5 The main difference between and is when the RRC reconfiguration messages are exchanged between the IAB donor CU 211 and the IAB donor CU 221 .

[0096] like Figure 5 As shown, the IAB MT 231 transmits 501 a measurement report to the IAB donor CU 211, for example via RRC signaling. In some example embodiments, the measurement report may be triggered by a configured HO event indicating a better connection quality on an alternative link to the IAB donor DU 222 under the IAB donor CU 221.

[0097] The IAB donor CU 211 decides 502 to hand over the IAB node 230 (radio connection with the IAB MT 231) to the cell served by the IAB donor 220. The handover process may be a normal handover process or any one of other mobility processes, such as conditional handover (CHO). It should be understood that the scope of the present disclosure is not limited to the selection of the HO process of the IAB MT 231.

[0098] The IAB donor CU 211 transmits 503 a HO request to the IAB donor CU 221. The HO request may be directed not only to the IAB MT 231 but also to the UE 240 connected to the IAB node 230 in the cell served by the IAB DU 232. It should be understood that the migrating IAB node 230 may also have descendants / child nodes, and during the migration process, connections should also be reconfigured for them, which is Figure 4 In some example embodiments, the HO request may include the F1AP interface of the IAB donor CU 211 and the context of the UE 240. It should be understood that context transfer may also occur with other signaling (eg, context retrieval) other than the HO request.

[0099] The IAB donor CU 221 performs 504 admission control by evaluating the possibility of accommodating the traffic moving with the IAB node 230. Here, it is assumed that the admission control of the IAB node 230 and the UE 240 is successful.

[0100] The IAB donor CU 221 transmits 505 to the IAB donor CU 211 an acknowledgement including the HO command of the IAB MT 231. Figure 4 Unlike, there is no RRC reconfiguration message of UE 240 in the confirmation. However, IAB donor CU 221 may indicate that the RRC reconfiguration message of UE 240 will be sent later. IAB donor CU 211 transmits 506 HO command to IAB MT 231.

[0101] The IAB donor CU 211 may indicate 507 to the IAB DU 232 via F1AP signaling that the F1 and UE context should be maintained even if a new F1 interface with the IAB donor CU 221 is established.

[0102] IAB node 230 initiates 508 a HO execution to the target cell (i.e., the cell served by IAB donor DU 222). In some example embodiments, the HO execution may immediately follow the HO command (i.e., normal HO procedure). Alternatively, if conditional HO is used, the configured CHO trigger may be used to initiate the HO execution.

[0103] The IAB MT 231 accesses 509 the target cell served by the IAB donor DU 222 and establishes an RRC connection to the IAB donor CU 221. The IAB MT 231 transmits 510 a HO complete message to the IAB donor CU 221.

[0104] The F1 establishment process is initiated to establish 511 the F1 interface 290 between the IAB DU 232 and the IAB donor CU 221. Once the F1 interface 290 is established, the IAB donor CU 221 may generate an RRC reconfiguration message for the UE 240. The RRC reconfiguration message may indicate a reconfiguration process with or without synchronization. If the RRC reconfiguration message indicates a reconfiguration process without synchronization, the UE 240 will not acquire uplink synchronization by performing a random access process because the cell(s) served by the IAB DU 232 have not changed. The IAB donor CU 221 transmits 512 an acknowledgment of the RRC reconfiguration message including the UE 240 to the IAB donor CU 211. The RRC reconfiguration message may include a new security configuration valid for the connection to the IAB donor CU 221, as well as target cell parameters. This delayed generation of the RRC reconfiguration message allows the IAB donor CU 221 to change the cell parameters of the IAB DU 232 (if necessary).

[0105] The IAB donor CU 211 encrypts the RRC reconfiguration message with its own security parameters and transmits 513 the encrypted RRC reconfiguration message back to the IAB donor CU 221. The IAB donor CU 221 transmits 514 the RRC reconfiguration message directly to the IAB DU 232 via F1AP signaling over the established F1 interface 290.

[0106] Since the cell(s) served by the IAB DU 232 continue to be active, even after the F1 interface 290 with the IAB donor CU 221 is established, the IAB DU 232 transmits 515 an RRC reconfiguration message to the UE 240 using the C-RNTI(s) that the UE 240 is monitoring. Because the encryption of the RRC reconfiguration message has been done using the security parameters of the IAB donor CU 211, the UE 240 will be able to decrypt and decode the message. The RRC reconfiguration message may include a new security configuration that is valid for the connection to the IAB donor CU 221. It should be noted that since the cell / PCI does not change, when the reconfiguration message is sent to the UE 240, the change of the serving CU of the UE 240 is gradual.

[0107] UE 240 transmits 516 the RRC reconfiguration complete message to IAB DU 232, and after UE 240 is controlled by IAB donor CU 221, IAB DU 232 forwards 517 the RRC reconfiguration complete message via F1AP signaling. After successful completion of the process, IAB donor CU 221 may release 518 the context in IAB donor CU 211 and perform path switching for traffic data.

[0108] Figure 6 A flow chart of an example method 600 for IAB communication according to some example embodiments of the present disclosure is shown. The method 600 may be implemented at the IAB donor 210 shown in FIG. 2a and / or FIG. 2b. Hereinafter, the IAB donor 210 is also referred to as a "first device", the IAB donor 220 is also referred to as a "second device", the IAB node 230 is also referred to as a "third device", and the UE 240 is also referred to as a "fourth device". It should be understood that the method 600 may include additional blocks not shown and / or some of the blocks shown may be omitted, and the scope of the present disclosure is not limited thereto.

[0109] At block 610, the first device receives a reconfiguration message from the second device for a fourth device in a serving cell served by a third device. The third device migrates from a first cell communicating with the first device to a second cell communicating with the second device while keeping the cell identifier of the serving cell unchanged. The reconfiguration message instructs the fourth device to update the configuration for the second device.

[0110] In some example embodiments, the reconfiguration message instructs the fourth device to update the configuration for the second device without performing a random access procedure.

[0111] In some example embodiments, the first device transmits a handover request to the second device, the handover request being used for handover of the third device from the first cell to the second cell and for reconfiguration of the fourth device. In response to the second device allowing the handover, the first device receives a handover confirmation from the second device, the handover confirmation including a handover command for the third device and a reconfiguration message for the fourth device.

[0112] In some example embodiments, the first device transmits a handover request to the second device, the handover request being used for handover of the third device from the first cell to the second cell and for reconfiguration of the fourth device. In response to the second device allowing the handover, the first device receives a handover confirmation from the second device, the handover confirmation including a handover command for the third device and an indication of delayed transmission of a reconfiguration message. For example, if only a HO confirmation for the third device is returned, the indication of delayed transmission may be implicit. In response to establishment of a second interface between the third device and the second device, the first device receives a reconfiguration message from the second device.

[0113] In some example embodiments, the handover request includes context information of the fourth device and of the first interface between the third device and the first device.

[0114] At block 620 , the first device encrypts the reconfiguration message based on security parameters of the first device.

[0115] At block 630 , the first device provides the encrypted reconfiguration message to the third device.

[0116] In some example embodiments, the first device transmits the encrypted reconfiguration message to the third device via a first interface between the third device and the first device.

[0117] In some example embodiments, the first device transmits the encrypted reconfiguration message to the second device via a third interface between the first device and the second device, causing the second device to transmit the encrypted reconfiguration message to the third device via a second interface between the third device and the second device.

[0118] In some example embodiments, the first device transmits an indication to retain the context information of the first interface and the fourth device to the third device via the first interface between the third device and the first device.

[0119] In some example embodiments, the first device is a first IAB donor (eg, IAB donor 210), the second device is a second IAB donor (eg, IAB donor 220), the third device is an IAB node (eg, IAB node 230), and the fourth device is a terminal device (eg, UE 240).

[0120] Figure 7 A flow chart of an example method 700 for IAB communication according to some example embodiments of the present disclosure is shown. The method 700 may be implemented at the IAB donor 220 as shown in FIG. 2a and / or FIG. 2b. Hereinafter, the IAB donor 210 is also referred to as a "first device", the IAB donor 220 is also referred to as a "second device", the IAB node 230 is also referred to as a "third device", and the UE 240 is also referred to as a "fourth device". It should be understood that the method 700 may include additional blocks not shown and / or some of the blocks shown may be omitted, and the scope of the present disclosure is not limited thereto.

[0121] At block 710, the second donor generates a reconfiguration message for a fourth device in a serving cell served by a third device, the third device migrating from a first cell communicating with the first device to a second cell communicating with the second device while maintaining a cell identifier of the serving cell unchanged. The reconfiguration message instructs the fourth device to update configuration for the second device.

[0122] At block 720 , the second device transmits a reconfiguration message to the first device.

[0123] In some example embodiments, the reconfiguration message instructs the fourth device to update the configuration for the second device without performing a random access procedure.

[0124] In some example embodiments, the second device receives a handover request from the first device, the handover request being for handover of the third device from the first cell to the second cell and for reconfiguration of the fourth device. The second device determines whether to allow handover based on the handover request. Based on the determination that handover is allowed, the second device generates a reconfiguration message and transmits a handover confirmation to the first device, the handover confirmation including a handover command for the third device and a reconfiguration message for the fourth device.

[0125] In some example embodiments, the second device receives a handover request from the first device, the handover request being used for handover of the third device from the first cell to the second cell and for reconfiguration of the fourth device. The second device determines whether to allow handover based on the handover request. Based on the determination that handover is allowed, the second device transmits a handover confirmation to the first device, the handover confirmation including a handover command for the third device and an indication of delayed transmission of the reconfiguration message. For example, if only an HO confirmation for the third device is returned, the indication of delayed transmission may be implicit. In response to the second interface between the third device and the second device being established, the second device generates a reconfiguration message and transmits another handover confirmation to the first device, the other handover confirmation including the generated reconfiguration message.

[0126] In some example embodiments, the handover request includes context information of the fourth device and of the first interface between the third device and the first device.

[0127] In some example embodiments, the second device receives a reconfiguration message encrypted based on a security parameter of the first device from the first device via a third interface between the first device and the second device. In response to a second interface between the third device and the second device being established, the second device transmits the reconfiguration message to the third device via the second interface.

[0128] In some example embodiments, the first device is a first IAB donor (eg, IAB donor 210), the second device is a second IAB donor (eg, IAB donor 220), the third device is an IAB node (eg, IAB node 230), and the fourth device is a terminal device (eg, UE 240).

[0129] Figure 8A flow chart of an example method 800 for IAB communication according to some example embodiments of the present disclosure is shown. The method 800 may be implemented at the IAB node 230 shown in FIG. 2a and / or FIG. 2b. Hereinafter, the IAB donor 210 is also referred to as a "first device", the IAB donor 220 is also referred to as a "second device", the IAB node 230 is also referred to as a "third device", and the UE 240 is also referred to as a "fourth device". It should be understood that the method 800 may include additional blocks not shown and / or some of the blocks shown may be omitted, and the scope of the present disclosure is not limited thereto.

[0130] In block 810, the third device receives a reconfiguration message for a fourth device in a serving cell served by the third device from the first device or the second device. The third device migrates from a first cell communicating with the first device to a second cell communicating with the second device while keeping the cell identifier of the serving cell unchanged. The reconfiguration message indicates that the fourth device updates the configuration for the second device.

[0131] At block 820 , the third device forwards the reconfiguration message to the fourth device.

[0132] At block 830 , the third device receives a reconfiguration complete message from the fourth device.

[0133] In some example embodiments, the reconfiguration message instructs the fourth device to update the configuration for the second device without performing a random access procedure.

[0134] In some example embodiments, the third device receives a reconfiguration message from the first device via a first interface between the third device and the first device, the reconfiguration message being encrypted based on a security parameter of the first device. In some example embodiments, the third device stores the reconfiguration message at the third device. In response to a trigger for transmission of the reconfiguration message, the third device transmits the reconfiguration message to the fourth device by keeping the identifier of the serving cell unchanged. In some example embodiments, the trigger includes any of the following: establishment of a second interface between an IAB anode and the second device; initiation of a handover process by a third device; or completion of a handover process by a third device.

[0135] In some example embodiments, the third device receives a reconfiguration message from the second device via a second interface between the third device and the second device, the reconfiguration message being encrypted based on a security parameter of the first device.

[0136] In some example embodiments, the third device receives from the first device via a first interface between the third device and the first device an indication to retain context information of the first interface and the fourth device; and stores the context information at the third device.

[0137] In some example embodiments, the first device is a first IAB donor (eg, IAB donor 210), the second device is a second IAB donor (eg, IAB donor 220), the third device is an IAB node (eg, IAB node 230), and the fourth device is a terminal device (eg, UE 240).

[0138] Fig. 9 A flow chart of an example method 900 for IAB communication according to some example embodiments of the present disclosure is shown. The method 900 may be implemented at a UE 240 as shown in FIG. 2a and / or FIG. 2b. Hereinafter, the IAB donor 210 is also referred to as a "first device", the IAB donor 220 is also referred to as a "second device", the IAB node 230 is also referred to as a "third device", and the UE 240 is also referred to as a "fourth device". It should be understood that the method 900 may include additional blocks not shown and / or some of the blocks shown may be omitted, and the scope of the present disclosure is not limited thereto.

[0139] At block 910, a fourth device receives a reconfiguration message from a third device, the third device providing a serving cell for serving the fourth device. The third device migrates from a first cell communicating with the first device to a second cell communicating with the second device, while keeping the cell identifier of the serving cell unchanged. The reconfiguration message includes a new configuration for the second device.

[0140] At block 920 , the fourth device updates the configuration used at the fourth device with the new configuration without performing a random access procedure.

[0141] At block 930 , the fourth device transmits a reconfiguration complete message to the third device.

[0142] In some example embodiments, the reconfiguration message is encrypted based on security parameters of the first device. The fourth device decrypts the reconfiguration message based on the security parameters of the first device and decodes the reconfiguration message to obtain the configuration for the second device.

[0143] In some example embodiments, the first device is a first IAB donor (eg, IAB donor 210), the second device is a second IAB donor (eg, IAB donor 220), the third device is an IAB node (eg, IAB node 230), and the fourth device is a terminal device (eg, UE 240).

[0144] In some example embodiments, an apparatus capable of executing method 600 may include a component for executing the corresponding steps 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.

[0145] In some example embodiments, an apparatus (e.g., IAB donor 210) capable of performing method 600 includes: a component for receiving, from a second device, a reconfiguration message for a fourth device in a serving cell served by a third device, the third device migrating from a first cell communicating with the apparatus to a second cell communicating with the second device while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message indicating that the fourth device updates a configuration for the second device; a component for encrypting the reconfiguration message based on a security parameter of the apparatus; and a component for providing the encrypted reconfiguration message to the third device.

[0146] In some example embodiments, the reconfiguration message instructs the fourth device to update the configuration for the second device without performing a random access procedure.

[0147] In some example embodiments, the component for receiving a reconfiguration message includes: a component for transmitting a switching request to a second device, the switching request being used for switching of a third device from a first cell to a second cell and for reconfiguration of a fourth device; and a component for receiving a switching confirmation from the second device in response to the second device allowing the switching, the switching confirmation including a switching command for the third device and a reconfiguration message for the fourth device.

[0148] In some example embodiments, the component for receiving a reconfiguration message includes: a component for transmitting a switching request to a second device, the switching request being used for switching of a third device from a first cell to a second cell and for reconfiguration of a fourth device; a component for receiving a switching confirmation from the second device in response to the second device allowing the switching, the switching confirmation including a switching command for the third device and an indication of delayed transmission of the reconfiguration message; and a component for receiving a reconfiguration message from the second device in response to a second interface between the third device and the second device being established.

[0149] In some example embodiments, the handover request includes context information of the fourth device and of the first interface between the third device and the apparatus.

[0150] In some example embodiments, means for providing the encrypted reconfiguration message to the third device comprises means for transmitting the encrypted reconfiguration message to the third device via a first interface between the third device and the apparatus.

[0151] In some example embodiments, the apparatus capable of executing method 600 further includes means for transmitting to the third device via the first interface between the third device and the apparatus an indication to retain the context information of the first interface and the fourth device.

[0152] In some example embodiments, the component for providing an encrypted reconfiguration message to a third device includes: a component for transmitting the encrypted reconfiguration message to the second device via a third interface between the apparatus and the second device, so that the second device transmits the encrypted reconfiguration message to the third device via a second interface between the third device and the second device.

[0153] In some example embodiments, the apparatus is a first IAB donor, the second device is a second IAB donor, the third device is an IAB node, and the fourth device is a terminal device.

[0154] In some example embodiments, an apparatus capable of executing method 700 may include a component for executing the corresponding steps 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.

[0155] In some example embodiments, an apparatus capable of performing method 700 (e.g., IAB donor 220) includes: a component for generating a reconfiguration message for a fourth device in a serving cell served by a third device, the third device migrating from a first cell communicating with a first device to a second cell communicating with the apparatus while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message instructing the fourth device to update a configuration for the apparatus; and a component for transmitting the reconfiguration message to the first device.

[0156] In some example embodiments, the reconfiguration message instructs the fourth device to update the configuration for the apparatus without performing a random access procedure.

[0157] In some example embodiments, the means for generating a reconfiguration message includes: a means for receiving a handover request from the first device, the handover request being for a handover of the third device from the first cell to the second cell and for reconfiguration of the fourth device; a means for determining whether to allow the handover based on the handover request; and a means for generating the reconfiguration message according to the determination that the handover is allowed. The means for transmitting the reconfiguration message to the first device includes: a means for transmitting a handover confirmation to the first device, the handover confirmation including a handover command for the third device and a reconfiguration message for the fourth device.

[0158] In some example embodiments, the means for generating the reconfiguration message includes: means for receiving a handover request from the first device, the handover request being for handover of the third device from the first cell to the second cell and for reconfiguration of the fourth device; means for determining whether to allow handover based on the handover request; means for transmitting a handover confirmation to the first device in accordance with the determination that handover is allowed, the handover confirmation including a handover command for the third device and an indication of delayed transmission of the reconfiguration message; and means for generating the reconfiguration message in response to the second interface between the third device and the apparatus being established. The means for transmitting the reconfiguration message to the first device includes: means for transmitting an additional handover confirmation to the first device, the additional handover confirmation including the generated reconfiguration message.

[0159] In some example embodiments, the handover request includes context information of the fourth device and of the first interface between the third device and the first device.

[0160] In some example embodiments, the apparatus capable of executing method 700 further includes: a component for receiving a reconfiguration message encrypted based on a security parameter of the first device from the first device via a third interface between the first device and the apparatus; and a component for transmitting the reconfiguration message to the third device via the second interface in response to a second interface between the third device and the apparatus being established.

[0161] In some example embodiments, the first device is a first IAB donor, the apparatus is a second IAB donor, the third device is an IAB node, and the fourth device is a terminal device.

[0162] In some example embodiments, an apparatus capable of executing method 800 may include a component for executing the corresponding steps of method 800. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module.

[0163] In some example embodiments, an apparatus (e.g., IAB node 230) capable of performing method 800 includes: a component for receiving a reconfiguration message for a fourth device in a service cell served by the apparatus from a first device or a second device, the apparatus migrating from a first cell communicating with the first device to a second cell communicating with the second device while keeping a cell identifier of the service cell unchanged, and the reconfiguration message indicating that the fourth device updates the configuration for the second device; a component for forwarding the reconfiguration message to the fourth device; and a component for receiving a reconfiguration completion message from the fourth device.

[0164] In some example embodiments, the reconfiguration message instructs the fourth device to update the configuration for the second device without performing a random access procedure.

[0165] In some example embodiments, means for receiving the reconfiguration message comprises means for receiving the reconfiguration message from the first device via a first interface between the apparatus and the first device, the reconfiguration message being encrypted based on a security parameter of the first device.

[0166] In some example embodiments, means for forwarding the reconfiguration message to the fourth device comprises means for storing the reconfiguration message at the apparatus; and means for transmitting the reconfiguration message to the fourth device in response to a trigger for transmission of the reconfiguration message.

[0167] In some example embodiments, the triggering includes any one of: establishment of a second interface between the apparatus and the second device; initiation of a handover process by the apparatus; or completion of a handover process by the apparatus.

[0168] In some example embodiments, the means for receiving the reconfiguration message comprises means for receiving the reconfiguration message from the second device via a second interface between the apparatus and the second device, the reconfiguration message being encrypted based on a security parameter of the first device.

[0169] In some example embodiments, an apparatus capable of performing method 800 further includes: a component for receiving an indication to retain context information of the first interface and a fourth device from the first device via a first interface between the apparatus and the first device; and a component for storing the context information at the apparatus.

[0170] In some example embodiments, the first device is a first IAB donor, the second device is a second IAB donor, the apparatus is an IAB node, and the fourth device is a terminal device.

[0171] In some example embodiments, a device capable of executing method 900 may include a component for executing the corresponding steps of method 900. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module.

[0172] In some example embodiments, an apparatus (e.g., UE 240) capable of performing method 900 includes: a component for receiving a reconfiguration message from a third device serving the apparatus, the third device migrating from a first cell communicating with the first device to a second cell communicating with the second device while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message includes a new configuration for the second device; a component for updating the configuration used at the apparatus with the new configuration without performing a random access procedure; and a component for transmitting a reconfiguration completion message to the third device.

[0173] In some example embodiments, the reconfiguration message is encrypted based on security parameters of the first device.An apparatus capable of performing method 900 further includes: means for decrypting the reconfiguration message based on the security parameters of the first device; and means for decoding the reconfiguration message to obtain a configuration for the second device.

[0174] In some example embodiments, the first device is a first IAB donor, the second device is a second IAB donor, the third device is an IAB node, and the apparatus is a terminal device.

[0175] In some example embodiments, in a multi-hop topology, the source service node for migrating the IAB MT is another IAB node under the first IAB donor.

[0176] In some example embodiments, in a multi-hop topology, the target service node for migrating the IAB MT is another IAB node under the second IAB donor.

[0177] Fig.10 2a and 2b. The IAB node 230, the IAB donor 210, the IAB donor 220 and / or the UE 240 shown in FIG. 2a and / or FIG. 2b may be implemented by the device 1000. As shown in the figure, the device 1000 includes one or more processors 1010, one or more memories 1020 coupled to the processor 1010, and one or more communication modules 1040 coupled to the processor 1010.

[0178] The communication module 1040 is used for two-way communication. The communication module 1040 has at least one antenna to facilitate communication. The communication interface may represent any interface necessary to communicate with other network elements.

[0179] Processor 1010 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 1000 may have multiple processors, such as application specific integrated circuit chips that are time slaved to a clock synchronized with a main processor.

[0180] The memory 1020 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) 1024, electrically programmable read-only memory (EPROM), flash memory, hard disk, compact disk (CD), digital video disk (DVD), and other magnetic storage and / or optical storage. Examples of volatile memories include, but are not limited to, random access memory (RAM) 1022 and other volatile memories that do not persist during power outages.

[0181] Computer program 1030 includes computer executable instructions executed by associated processor 1010. Program 1030 may be stored in ROM 1024. Processor 1010 may perform any suitable actions and processes by loading program 1030 into RAM 1022.

[0182] The embodiments of the present disclosure may be implemented by the program 1030 so that the device 1000 may execute the reference Figure 3-Figure 9 Any process of the present disclosure discussed. The embodiments of the present disclosure may also be implemented by hardware or a combination of software and hardware.

[0183] In some example embodiments, the program 1030 may be tangibly embodied in a computer-readable medium, which may be included in the device 1000 (such as in the memory 1020) or in other storage devices accessible to the device 1000. The device 1000 may load the program 1030 from the computer-readable medium to the RAM 1022 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.11 An example of a computer readable medium 1100 is shown which may be in the form of a CD or DVD. The computer readable medium has a program 1030 stored thereon.

[0184] It should be recognized that future networks may utilize network function virtualization (NFV), which is a network architecture concept that proposes virtualizing network node functions into "building blocks" or entities that can be operationally connected or linked together to provide services. A virtualized network function (VNF) may include one or more virtual machines that run computer program code using standard or general-purpose servers rather than custom hardware. Cloud computing or data storage may also be utilized. In radio communications, this may mean that node operations are at least partially performed in a central / centralized unit CU (e.g., a server, host, or node) that is operationally coupled to a distributed unit DU (e.g., a radio head / node). Node operations may also be distributed among multiple servers, nodes, or hosts. It should also be understood that the distribution of work between core network operations and base station operations may vary from implementation to implementation.

[0185] In one embodiment, the server can generate a virtual network through which the server communicates with the distributed units. In general, a virtual network can involve the process of combining hardware and software network resources and network functions into a single software-based management entity (virtual network). Such a virtual network can provide a flexible distribution of operations between the server and the radio head / node. In practice, any digital signal processing task can be performed in the CU or DU, and the boundary at which responsibility is transferred between the CU and the DU can be selected according to the implementation.

[0186] Thus, in one embodiment, a CU-DU architecture is implemented. In this case, the device 1000 may be included in a central unit (e.g., a control unit, an edge cloud server, a server), which is operably coupled (e.g., via a wireless or wired network) to a distributed unit (e.g., a remote radio head / node). That is, the central unit (e.g., an edge cloud server) and the distributed units may be independent devices that communicate with each other via a radio path or via a wired connection. Alternatively, they may be located in the same entity that communicates via a wired connection, etc. The edge cloud or edge cloud server may serve multiple distributed units or radio access networks. In one embodiment, at least some of the above processes may be performed by the central unit. In another embodiment, the device 1000 may instead be included in a distributed unit, and at least some of the above processes may be performed by the distributed unit.

[0187] In one embodiment, the execution of at least some of the functions of the device 1000 can be shared between two physically separate devices (DU and CU) that form an operational entity. Therefore, it can be seen that the device depicts an operational entity including one or more physically separate devices for performing at least some of the above-mentioned processes. In one embodiment, such a CU-DU architecture can provide a flexible allocation of operations between the CU and the DU. In practice, any digital signal processing task can be performed in the CU or the DU, and the boundary at which responsibility is transferred between the CU and the DU can be selected according to the implementation. In one embodiment, the device 1000 controls the execution of the above-mentioned processes regardless of the location of the above-mentioned devices and regardless of where the above-mentioned processes / functions are executed.

[0188] 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.

[0189] 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 real or virtual processor to perform the above referenced Figure 6 The method 600 described above with reference to Figure 7 The method 700 described above with reference to Figure 8 The method 800 described and / or referenced above Fig. 9 Method 900 described. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. In various embodiments, the functions of program modules can be combined or split between program modules as needed. The machine executable instructions of program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in both local and remote storage media.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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.

[0194] 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 method comprising: At a first device, receiving a reconfiguration message for a fourth device from a second device, the fourth device being in a serving cell served by a third device, the third device migrating from a first cell communicating with the first device to a second cell communicating with the second device while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message instructing the fourth device to update a configuration for the second device, the reconfiguration message indicating a reconfiguration process without synchronization; encrypting the reconfiguration message based on a security parameter of the first device; providing the encrypted reconfiguration message to the third device, the reconfiguration message comprising a new security configuration effective for a connection to the second device; as well as Transmitting, via a first interface between the third device and the first device, to the third device an instruction to retain context information of the first interface and the fourth device; Wherein receiving the reconfiguration message comprises: transmitting a handover request to the second device, where the handover request is used for handover of the third device from the first cell to the second cell and for reconfiguration of the fourth device; In response to the second device allowing the handover, receiving a handover confirmation from the second device, the handover confirmation including a handover command for the third device and an indication of delayed transmission of the reconfiguration message; and In response to a second interface between the third device and the second device being established, receiving the reconfiguration message from the second device; Wherein providing the encrypted reconfiguration message to the third device comprises: The encrypted reconfiguration message is transmitted to the second device via a third interface between the first device and the second device, so that the second device transmits the encrypted reconfiguration message to the third device via a second interface between the third device and the second device. 2 . The method according to claim 1 , wherein the reconfiguration message instructs the fourth device to update the configuration for the second device without performing a random access procedure.

3. The method of claim 1, wherein receiving the reconfiguration message further comprises: transmitting a handover request to the second device, where the handover request is used for handover of the third device from the first cell to the second cell and for reconfiguration of the fourth device; as well as In response to the second device allowing the handover, a handover confirmation is received from the second device, the handover confirmation including a handover command for the third device and the reconfiguration message for the fourth device. 4 . The method according to claim 3 , wherein the handover request comprises context information of the fourth device and of a first interface between the third device and the first device.

5. The method of claim 1 , wherein providing the encrypted reconfiguration message to the third device further comprises: The encrypted reconfiguration message is transmitted to the third device via a first interface between the third device and the first device.

6. The method according to claim 1, wherein: The first device is a first integrated access and backhaul donor; The second device is a second integrated access and backhaul donor; The third device is an integrated access and backhaul node; and The fourth device is a terminal device.

7. A method comprising: generating, at the second device, a reconfiguration message for a fourth device, the fourth device being in a serving cell served by a third device, the third device migrating from a first cell communicating with the first device to a second cell communicating with the second device while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message instructing the fourth device to update a configuration for the second device, the reconfiguration message indicating a reconfiguration process without synchronization; transmitting the reconfiguration message to the first device; receiving, from the first device via a third interface between the first device and the second device, the reconfiguration message encrypted based on security parameters of the first device, the reconfiguration message comprising a new security configuration effective for a connection to the second device; as well as In response to a second interface between the third device and the second device being established, transmitting the reconfiguration message to the third device via the second interface; Wherein generating the reconfiguration message comprises: receiving a handover request from the first device, where the handover request is used for handover of the third device from the first cell to the second cell and for reconfiguration of the fourth device; determining whether to allow the handover based on the handover request; Based on the determination that the handover is allowed, transmitting a handover confirmation to the first device, the handover confirmation including a handover command for the third device and an indication of delayed transmission of the reconfiguration message; and generating the reconfiguration message in response to a second interface between the third device and the second device being established; and Wherein transmitting the reconfiguration message to the first device comprises: A further handover confirmation is transmitted to the first device, the further handover confirmation comprising the generated reconfiguration message.

8. The method of claim 7, wherein the reconfiguration message instructs the fourth device to update the configuration for the second device without performing a random access procedure.

9. The method according to claim 7, Wherein generating the reconfiguration message comprises: receiving a handover request from the first device, where the handover request is used for handover of the third device from the first cell to the second cell and for reconfiguration of the fourth device; determining whether to allow the handover based on the handover request; as well as generating the reconfiguration message based on a determination that the switching is permitted; as well as Wherein transmitting the reconfiguration message to the first device comprises: A handover confirmation is transmitted to the first device, the handover confirmation including the handover command for the third device and the generated reconfiguration message for the fourth device. 10 . The method of claim 7 , wherein the handover request comprises context information of the fourth device and of a first interface between the third device and the first device.

11. The method according to claim 7, wherein: The first device is a first integrated access and backhaul donor; The second device is a second integrated access and backhaul donor; The third device is an integrated access and backhaul node; and The fourth device is a terminal device.

12. A method comprising: At a third device, receiving a reconfiguration message for a fourth device from the first device or the second device, the fourth device being in a serving cell served by the third device, the third device migrating from a first cell communicating with the first device to a second cell communicating with the second device while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message instructing the fourth device to update a configuration for the second device, the reconfiguration message indicating a reconfiguration process without synchronization; forwarding the reconfiguration message to the fourth device; receiving a reconfiguration completion message from the fourth device; receiving, from the first device via a first interface between the third device and the first device, an instruction to retain context information of the first interface and the fourth device; as well as storing the context information at the third device; Wherein receiving the reconfiguration message comprises: The first device transmits a handover request to the second device, where the handover request is used for handover of the third device from the first cell to the second cell and for reconfiguration of the fourth device; The first device receives, in response to the second device allowing the switching, a switching confirmation from the second device, the switching confirmation including a switching command for the third device and an indication of delayed transmission of the reconfiguration message; In response to a second interface between the third device and the second device being established, the first device receives the reconfiguration message from the second device; the first device encrypting the reconfiguration message based on security parameters of the first device, the reconfiguration message comprising a new security configuration effective for a connection to the second device; The first device transmits the encrypted reconfiguration message to the second device via a third interface between the first device and the second device; and The third device receives the encrypted reconfiguration message from the second device via a second interface between the third device and the second device.

13. The method of claim 12, wherein the reconfiguration message instructs the fourth device to update the configuration for the second device without performing a random access procedure.

14. The method of claim 12, wherein receiving the reconfiguration message comprises: The reconfiguration message is received from the first device via a first interface between the third device and the first device, the reconfiguration message being encrypted based on a security parameter of the first device.

15. The method according to claim 14, wherein forwarding the reconfiguration message to the fourth device comprises: storing the reconfiguration message at the third device; as well as In response to a trigger for transmission of the reconfiguration message, transmitting the reconfiguration message to the fourth device.

16. The method according to claim 15, wherein the trigger comprises any one of the following: establishing a second interface between the IAB anode and the second device; The switching process is initiated by the third device; or The switching process is completed by the third device.

17. The method of claim 12, wherein: The first device is a first integrated access and backhaul donor; The second device is a second integrated access and backhaul donor; The third device is an integrated access and backhaul node; and The fourth device is a terminal device.

18. A method comprising: At a fourth device, receiving a reconfiguration message from a third device, the third device providing a serving cell for serving the fourth device, the third device migrating from a first cell communicating with a first device to a second cell communicating with a second device while keeping a cell identifier of the serving cell unchanged, and the reconfiguration message including a new configuration for the second device, the reconfiguration message including a new security configuration valid for a connection to the second device; updating a configuration used at the fourth device with the new configuration without performing a random access procedure; as well as Transmitting a reconfiguration completion message to the third device; Wherein receiving the reconfiguration message comprises: The first device transmits a handover request to the second device, where the handover request is used for handover of the third device from the first cell to the second cell and for reconfiguration of the fourth device; The first device receives, in response to the second device allowing the switching, a switching confirmation from the second device, the switching confirmation including a switching command for the third device and an indication of delayed transmission of the reconfiguration message; In response to a second interface between the third device and the second device being established, the first device receives the reconfiguration message from the second device; the first device encrypting the reconfiguration message based on security parameters of the first device, the reconfiguration message comprising a new security configuration effective for a connection to the second device; The first device transmits the encrypted reconfiguration message to the second device via a third interface between the first device and the second device; The third device receives the encrypted reconfiguration message from the second device via a second interface between the third device and the second device; and The fourth device receives the encrypted reconfiguration information from the third device; The method further comprises: decrypting the reconfiguration message based on the security parameter of the first device; and The reconfiguration message is decoded to obtain the configuration of the second device.

19. The method of claim 18, wherein: The first device is a first integrated access and backhaul donor; The second device is a second integrated access and backhaul donor; The third device is an integrated access and backhaul node; and The fourth device is a terminal device.

20. A first device, comprising: at least one processor; as well as at least one memory including computer program code; The at least one memory and the computer program code are configured to, together with the at least one processor, cause the first device to perform a method according to any one of claims 1 to 6.

21. A second device, comprising: at least one processor; as well as at least one memory including computer program code; The at least one memory and the computer program code are configured to, together with the at least one processor, cause the second device to perform a method according to any one of claims 7 to 11.

22. A third device, comprising: at least one processor; as well as at least one memory including computer program code; The at least one memory and the computer program code are configured to, together with the at least one processor, cause the third device to perform the method according to any one of claims 12 to 17.

23. A fourth device, comprising: at least one processor; as well as at least one memory including computer program code; The at least one memory and the computer program code are configured to, together with the at least one processor, cause the fourth device to perform a method according to any one of claims 18 to 19.

24. An apparatus comprising means for performing the method according to any one of claims 1 to 6.

25. An apparatus comprising means for performing the method according to any one of claims 7 to 11.

26. An apparatus comprising means for performing the method according to any one of claims 12 to 17.

27. An apparatus comprising means for performing the method according to any one of claims 18 to 19.

28. A computer program product stored on a computer readable medium and comprising machine executable instructions, wherein the machine executable instructions, when executed, cause a machine to perform the method according to any one of claims 1 to 19.

29. A computer-readable storage medium comprising program instructions stored thereon, which instructions, when executed by an apparatus, cause the apparatus to perform the method according to any one of claims 1 to 19.

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