Reduce signaling when switching IAB nodes

Abstract

Example embodiments of the present disclosure relate to devices, methods, apparatuses, and computer-readable storage media for reducing signaling when switching an IAB node. The method includes: sending a request message from a first device to a second device for a third device to switch from the first device to the second device, the request message including a first cell configuration of the third device associated with the first device; receiving a response message confirming the request from the second device, the response message including a resource configuration for a connection between the third device and the second device and a second cell configuration of the third device associated with the second device; and sending the resource configuration to the third device. In this way, the signal overhead for the switching of the IAB node can be significantly reduced.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the field of telecommunications, and more particularly to a device, method, apparatus, and computer-readable medium for reducing signaling when switching an IAB node. Background Art

[0002] Integrated Access and Backhaul (IAB) enables wireless relay for New Radio (NR) access by using NR for backhaul. Relay nodes are called IAB nodes. The terminating node for NR backhaul on the network side is called IAB donor. IAB donor represents a gNB with additional functionality to support IAB. Backhaul can occur via a single hop or via multiple hops.

[0003] An IAB node may change its attachment point from a source IAB donor to a target IAB donor that is different from the source IAB donor. This behavior may be referred to as inter-gNB handover of an IAB node. Even if the IAB node is initially assumed to be stationary, network-controlled topology adaptation may be based on the handover process. Furthermore, mobile IAB nodes are also expected to be under development. Summary of the invention

[0004] Generally, example embodiments of the present disclosure provide a solution to reduce signaling when an IAB node is switched.

[0005] In a first aspect, a method implemented at a first device is provided. The method includes: sending a request message from the first device to a second device for a third device to switch from the first device to the second device, the request message including a first cell configuration of the third device associated with the first device; receiving a response message from the second device confirming the request, the response message including a resource configuration for a connection between the third device and the second device and a second cell configuration of the third device associated with the second device; and sending the resource configuration to the third device.

[0006] In a second aspect, a method implemented at a second device is provided. The method includes: receiving, at the second device, a request message for a third device to switch from the first device to the second device, the request message including a first cell configuration of the third device associated with the first device; sending a response message confirming the request, the response message including a resource configuration for a connection between the third device and the second device and a second cell configuration of the third device associated with the second device; and receiving, from the third device, a second message indicating that the connection between the third device and the second device has been successfully established.

[0007] In a third aspect, a method implemented at a third device is provided. The method includes: receiving, at the third device, a resource configuration for a connection between the third device and a second device from a first device; establishing a connection based at least on the resource configuration; and sending a second message to the second device indicating that the connection has been successfully established, so that the second device removes at least one original cell to be removed from the third device from a set of potential target cells for further handover to the first device based on a first cell configuration of the third device associated with the first device.

[0008] In a fourth aspect, a first device is provided. The first device comprises at least one processor and at least one memory comprising 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 the method of the first aspect.

[0009] In a fifth 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, together with the at least one processor, cause the second device to perform the method of the second aspect.

[0010] In a sixth aspect, a method implemented at a third 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, together with the at least one processor, cause the second device to perform the method of the third aspect.

[0011] In a seventh aspect, there is provided a computer readable medium comprising a computer program to cause an apparatus to at least perform the method according to the first aspect.

[0012] In an eighth aspect, there is provided a computer readable medium comprising a computer program to cause an apparatus to at least perform the method according to the second aspect.

[0013] In a ninth aspect, there is provided a computer readable medium comprising a computer program to cause an apparatus to at least perform the method according to the third aspect.

[0014] It is to be understood that the summary of the invention section is not intended to identify key or essential features of the embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become readily apparent through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0016] Figure 1 illustrates an example communication network in which embodiments of the present disclosure may be implemented;

[0017] Figure 2 shows a signaling diagram illustrating a process of reducing signaling upon IAB node handover according to some example embodiments of the present disclosure;

[0018] Figure 3 A flowchart showing a method implemented at a first device according to some example embodiments of the present disclosure is shown;

[0019] Figure 4 A flowchart showing a method implemented at a second device according to some example embodiments of the present disclosure is shown;

[0020] Figure 5 A flowchart showing a method implemented at a third device according to some example embodiments of the present disclosure is shown;

[0021] Figure 6 illustrates a simplified block diagram of an apparatus suitable for implementing some other embodiments of the present disclosure; and

[0022] Figure 7 A block diagram of an example computer-readable medium according to some example embodiments of the present disclosure is illustrated.

[0023] Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0024] The principles of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for illustrative purposes and to help those skilled in the art understand and implement the present disclosure without any limitation to the scope of the present disclosure. In addition to the methods described below, the present disclosure described herein can be implemented in various ways.

[0025] 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.

[0026] References in this disclosure to "one embodiment," "an embodiment," "an example embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment may include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in conjunction with an example embodiment, it is claimed that it is within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments, whether or not explicitly described.

[0027] It should be understood that, although the terms "first" and "second" etc. may be used to describe various elements in this article, these elements should not be limited by these terms. These terms are only used to distinguish elements from each other. For example, without departing from the scope of the exemplary embodiment, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items.

[0028] The terms used herein are used only to describe specific embodiments and are not intended to limit the example embodiments. As used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It is also to be understood that when used herein, the terms "comprises", "comprising", "has", "having", "includes", and / or "including" specify the presence of stated 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.

[0029] As used in this application, the term "circuitry" may refer to one or more or all of the following:

[0030] (a) hardware circuit implementation only (such as implementation only in analog and / or digital circuitry); and

[0031] (b) a combination of hardware circuitry and software such as (where applicable):

[0032] (i) a combination of analog and / or digital hardware circuits and software / firmware, and

[0033] (ii) any portion of hardware processor(s) with software (including digital signal processor(s)), software and memory(s) that work together to enable a device such as a mobile phone or server to perform various functions) and

[0034] (c) Hardware circuit(s) and / or processor(s), such as microprocessor(s) or portion(s) of microprocessor(s), that require software (e.g., firmware) to operate, but which software may not be present when not required for operation.

[0035] This definition of circuitry applies to all uses of the term in this application, including in any claims. As yet another example, as used in this application, the term circuitry would also cover implementations of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. For example and if applicable to a particular claim element, the term circuitry would also cover a baseband integrated circuit or processor integrated circuit for a mobile device or similar integrated circuit in a server, cellular network device, or other computing or network device.

[0036] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard, such as a fifth generation (5G) system, long term evolution (LTE), advanced LTE (LTE-A), wideband code division multiple access (WCDMA), high speed packet access (HSPA), narrowband Internet of Things (NB-IoT), etc. In addition, the communication between the terminal device and the network device in the communication network can be performed according to any suitable generation of communication protocols, 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) new radio (NR) 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 in various communication systems. In view of the rapid development of communication, there will certainly be future types of communication technologies and systems in which the present disclosure can be implemented. It should not be considered that the scope of the present disclosure is limited to the above-mentioned system.

[0037] As used herein, the term "network device" refers to a node in a communication network via which a terminal device accesses the network and receives services from it. A network device may refer to a base station (BS) or an access point (AP), such as a NodeB (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR next generation NodeB (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 node, a micro node), etc., depending on the terminology and technology of the application. The RAN split architecture includes a gNB-CU (centralized unit, hosting RRC, SDAP and PDCP) that controls multiple gNB-DUs (distributed units, hosting RLC, MAC and PHY). A relay node may correspond to the DU portion of an IAB node.

[0038] The term "terminal device" refers to any final device that may be capable of wireless communication. By way of 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 computer installation device (LME), a USB dongle, a smart device, a wireless customer premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable device, a head mounted display (HMD), a vehicle, a drone, medical equipment and applications (such as remote surgery), industrial equipment and applications (such as robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronic devices, equipment operating on commercial and / or industrial wireless networks, etc. The terminal device may also correspond to the mobile terminal (MT) part in an integrated access and backhaul (IAB) node (also known as a relay node). In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

[0039] Although in various example embodiments, the functionality described herein may be performed in fixed and / or wireless network nodes, in other example embodiments, the functionality may be implemented in a user equipment device (such as a cellular phone or tablet computer or laptop or desktop computer or mobile IoT device or fixed IoT device). Where appropriate, the user equipment device may, for example, be equipped with corresponding capabilities 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 processor, configured to control the user device when installed therein. Examples of such functionality include boot server functions and / or home subscriber servers, which may be implemented in the user equipment device by providing software to the user equipment device, the software being configured to cause the user equipment device to perform from the perspective of these functions / nodes.

[0040] Figure 1An example communication environment 100 in which embodiments of the present disclosure may be implemented is shown. The communication network 100 includes a first device 110, a second device 120, and a third device 130. In this example, the third device 120 is illustrated as an IAB node, and the first device 110 and the second device 120 are illustrated as an IAB donor (such as a gNB) serving the IAB node. It is to be understood that the number of the first device, the second device, and the third device is given for illustrative purposes and does not impose any limitation on the present disclosure. The communication network 100 may include any suitable number of first devices, second devices, and third devices suitable for implementing embodiments of the present disclosure.

[0041] The communication in the communication environment 100 may be implemented according to any appropriate (multiple) communication protocols, including but not limited to cellular communication protocols of the first generation (1G), second generation (2G), third generation (3G), fourth generation (4G) and fifth generation (5G), wireless local network communication protocols (such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, etc.), and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any appropriate wireless communication technology, including but not limited to: code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplex (FDD), time division duplex (TDD), multiple input multiple output (MIMO), orthogonal frequency division multiple access (OFDM), and / or any other technology currently known or to be developed in the future.

[0042] The third device 130 may include an MT 131, a DU 132, and a second DU 133. The third device 130 is connected to the second device 120 or the first device 110 via the MT 131. The third device 130 establishes an RLC channel to the MT of the terminal device and the downstream IAB node (not shown) via the DUs 132 and 133. Each of the first DU 132 and the second DU 133 has an F1-C connection with only one IAB donor CU-CP. For example, the first DU 132 may have a first F1 interface with the CU 122 in the second device 120, and the second DU 133 may have a second F1 interface with the CU 112 in the first device 110. In another embodiment, the third device 130 may have only one DU. Until the implementation of the IAB, the DU in the third device 130 may dynamically switch the F1 interface between the connection with the CU 122 in the second device 120 and the connection with the CU 112 in the first device 110. For convenience of description, the DU connected to the CU 122 is referred to as DU 132 , and the DU connected to the CU 112 is referred to as DU 133 .

[0043] The second device 120 includes at least one DU 121 to support terminal devices and MTs of one or more downstream IAB nodes. The second device 120 also includes a CU 122 for interfacing the DU of the IAB node with its own DU 121. Similarly, the first device 110 includes at least one DU 111 to support terminal devices and MTs of one or more downstream IAB nodes. The first device 110 also includes a CU 112 for interfacing the DU of the IAB node with its own DU 111. It is assumed that a given DU on an IAB node is served by only one IAB donor. The IAB donor may change through topology adaptation.

[0044] It should be understood that although DU 121 and CU 122 are illustrated as being implemented on a single entity, DU 121 and CU 122 may be implemented on multiple separate entities. Similarly, DU 111 and CU 112 may be implemented on a single entity or multiple separate entities.

[0045] In some example embodiments, DU 132 in third device 130 is connected to CU 122 in second device 120 or CU 112 in first device 110 using an F1 interface. The F1 user plane interface (F1-U) operates over an RLC channel on a wireless backhaul between MT 131 in third device 130 and DU 121 in second device 120 or DU 111 in first device 110.

[0046] As mentioned above, an IAB node may change its attachment point from a source IAB donor to a target IAB donor that is different from the source IAB donor. This behavior may be referred to as inter-gNB handover of an IAB node. Even if the IAB node is initially assumed to be stationary, network-controlled topology adaptation may be based on the handover process. Furthermore, mobile IAB nodes are also expected to be under development.

[0047] For example, the third device 130 has an attachment point to the CU 112 in the first device 110. Therefore, the first device 110 is also referred to as the source IAB donor. During the handover process, the third device 130 changes its attachment point from the CU 112 in the first device 110 to the CU 122 in the second device 110. Therefore, the second device 120 is also referred to as the target IAB donor.

[0048] To handle terminal mobility, gNBs connected via the Xn interface make each other aware of the cells they provide. Cell updates provided by a gNB are signaled to other gNBs using the NG-RAN Node Configuration Update in the Xn Application Protocol (AP) signaling protocol.

[0049] When the MT portion of the IAB node (e.g., MT 131 in the third device 130) is commanded to switch from a source donor gNB (e.g., the first device 110) to a target donor gNB (e.g., the second device 120), the radio cells functionally provided by its IAB node DU (e.g., DU 132 in the third device 130) may need to undergo some changes. For example, the NR cell global identity (CGI) of those radio cells may need to change because part of the NR CGI is the gNB identifier. In another embodiment, the physical cell identifier (PCI) of those radio cells needs to change.

[0050] According to the definition of this XnAP procedure, each inter-gNB handover of an IAB node needs to be accompanied by the following XnAP procedures, namely, handover preparation (for IAB MT; UE-associated XnAP procedure) and NG-RAN node configuration update (non-UE-associated XnAP procedure).

[0051] Additionally, in conjunction with the handover of the IAB node, the DU in the third device 130 needs to set up an F1 interface with the target donor gNB. In addition, the target donor gNB needs to know after which point in time it can issue handover commands to the UEs served by the IAB node (at least these handover commands may be required because the target gNB is the new network-side PDCP termination point for these UEs). Therefore, an F1AP procedure between the IAB DU and the target donor gNB may be required.

[0052] Specifically, through conventional means, a switching request message for the IAB node can be transmitted from the source IAB donor to the target IAB donor according to XnAP, and the target IAB donor can respond to the switching request using the switching request confirmation message of the IAB node (containing RRC reconfiguration information, i.e., the switching command), which can be referred to as the UE-associated XnAP procedure, as mentioned above.

[0053] The source IAB donor may then command the IAB node to block radio cells with a given NR CGI associated with the source IAB donor and transmit the RRC reconfiguration information received from the target IAB donor to the IAB node. Once the RRC reconfiguration is completed at the IAB node, the IAB may transmit an indication of the RRC reconfiguration completion to the target donor node.

[0054] In conjunction with the RRC reconfiguration, the DU in the IAB node sets up the Fl interface with the target donor, and the target donor node may command the IAB node to activate and allocate a radio cell with a new NR CGI associated with the target donor node according to the F1AP. Once the IAB node confirms the activation and the new NR CGI, the target IAB node may transmit update information about the NG-RAN node configuration indicating updated cell information to the source IAB donor node according to the XnAP, and the source IAB donor node may respond to the update information with the removed NR CGI, which may be referred to as a non-UE associated XnAP procedure, as mentioned above.

[0055] The F1 interface setup with the target IAB donor node and the two XnAP procedures may result in considerable signaling overhead for IAB node handover. Therefore, an embodiment of the present disclosure proposes a method for reducing handover signaling, aiming to merge the required UE-associated handover preparation procedure and the non-UE-associated NG-RAN node configuration update procedure, and transmit IAB-DU configuration information during the handover preparation procedure to reduce the F1 interface setup.

[0056] The principles and implementations of the present disclosure will be described below with reference to Figures 2 to 5 Describe in more detail. Figure 2 A signaling diagram illustrating a process 200 for reducing signaling when an IAB node switches according to some example embodiments of the present disclosure is shown. For discussion purposes, the process 200 will refer to Figure 1 Process 200 may involve Figure 1 The illustrated first device 110, the second device 120, and the third device 130. It is to be understood that although the process 200 has been Figure 1 The process is described in the communication system 100, but the process can also be applied to other communication scenarios.

[0057] like Figure 2 As shown, the third device 130 may pre-establish 205 a communication interface with the second device 120. In some example embodiments, the communication interface is an F1 interface. It should be understood that the F1 interface is only an example, and any suitable communication interface may be used between the third device 130 and the first device 110. In some other example embodiments, this step may not be performed, for example, when the third device 130 has only one DU.

[0058] In some example embodiments, in order to establish the communication interface, the third device 130 sends a request message for establishing the communication interface to the first device 110. The first device 110 forwards the request to the second device 120. In response to receiving the request from the first device 110, the second device 120 establishes the communication interface. Then, the second device 120 sends a response indicating the establishment of the communication interface to the first device 110. The first device 110 forwards the response to the third device 130.

[0059] In an example embodiment where the communication interface is an F1 interface, the request message for establishing the communication interface may be an F1 setup request message, and the response may be an F1 setup response message.

[0060] Continue to refer to Figure 2 , the handover may be initiated by the first device 110. The first device 110 sends 210 an Xn handover request message to the second device 120 to initiate handover preparation. In the Xn handover request message, a cell configuration of the third device 130 associated with the first device 110 is included.

[0061] In some other example embodiments, the handover may be performed via an NG interface, such as when there is no Xn interface between the first device 110 and the second device 120, or the Xn interface is available but cannot be used for Xn-based handover due to configuration.

[0062] In an example embodiment, the cell configuration information of the third device 130 associated with the first device 110 may include an indication of the NR CGI of at least one existing cell of the third device 130. The cell configuration information may also include detailed information of a serving cell of the third device 130. The cell configuration information may include a DU identity, a DU name, a tracking area code (TAC), a PLMNID, NR mode information, a physical cell identifier (PCI), system information, an RRC version, and other information typically included in an F1 setup request message. At least one existing cell may be removed from the third device 130 during the handover process, or may be removed from the third device 130 after the handover is completed.

[0063] Once the second device 120 receives the Xn handover request message from the first device 110, the second device 120 generates 215 an Xn handover request confirmation message having a resource configuration for the third device 130 based on the request. In response to the Xn handover request message, the Xn handover request confirmation message is transmitted from the second device 120 to the first device 110. In an example embodiment, the resource configuration may be referred to as information about “RRC reconfiguration”.

[0064] The second device 120 may also configure a new cell configuration (eg, a second cell configuration) for the third device 130 to adopt after the handover process is completed.

[0065] In an example embodiment, the new cell configuration may include the NR CGI of the cell, the new PCI, the new system information, the cell to be activated, and other configuration information to be allocated to the third device 130. The second device 120 may determine at least one new cell to be allocated to the third device 130, and generate a new cell configuration including a new identifier of the at least one new cell.

[0066] When the second device sends 220 an Xn handover request confirm message with a resource configuration, the new cell configuration may also be transmitted to the first device 110 together with the resource configuration via a message such as an NG handover request confirm message.

[0067] If the first device 110 receives the resource configuration, the first device 110 may instruct 225 the third device 130 to block the radio cell having the given NR CGI associated with the first device 110, and send 230 the resource configuration received from the second device 120 to the third device 130. In some example embodiments, the resource configuration may be transmitted by an RRC reconfiguration message. In some other example embodiments, action 225 and action 230 may be combined in one step.

[0068] In some example embodiments, the RRC reconfiguration message may be transmitted from DU 111 in first device 110 to MT 131 in third device 130. In some example embodiments, the RRC reconfiguration message may include a new cell configuration of at least one new cell allocated to third device 130, including NR CGI, new PCI, new system information, a cell to be activated, and other configuration information typically included in an F1 setup response message, and the at least one new cell may be provided by DU 132 under second device 120. Third device 130 saves the received new cell configuration associated with second device 120.

[0069] Once the RRC reconfiguration is completed at the third device 130, the third device 130 sends 235 a message to the second device 120 indicating that the RRC reconfiguration is complete. In some example embodiments, the message may be an RRC reconfiguration complete message. In some example embodiments, the RRC reconfiguration complete message may include an indication for confirming that the new cell configuration is adopted after the handover is completed. The third device 130 also begins to use the saved cell information configuration associated with the second device 120.

[0070] If second device 120 receives a message indicating that the RRC reconfiguration is complete from third device 130, second device 120 may determine 240 completion of the handover procedure. That is, third device 130 receiving the message confirming that the RRC reconfiguration is complete may be considered as a point in time when the handover should be considered successfully completed for third device 130. In some example embodiments, third device 130 receiving the message confirming that the RRC reconfiguration is complete may be considered as a point in time when the new cell configuration provided by second device 120 has been accepted by third device 130.

[0071] If the second device 120 receives a message indicating that the RRC reconfiguration is complete from the third device 130, that is, the connection between the third device 130 and the second device 120 has been successfully established, the second device 120 removes at least one original cell from the set of potential target cells for further handover to the first device. The second device 120 may determine at least one original cell that should be removed from the third device 130 based on the original cell configuration received from the first device 110 via the handover request.

[0072] In addition, the second device 120 can transmit 245 an indication message indicating a successful handover to the first device 110, and based on the new cell configuration received from the second device 120 in the handover request confirmation message, the first device 110 can determine 250 at least one available cell as a potential target cell for further handover to the second device 120.

[0073] In some example embodiments, the second device 120 may also send another indication to the first device 110 to release the context associated with the third device 130. Once the indication is received, the first device may determine the completion of the handover process. That is, the receipt of the indication for releasing the context associated with the third device may be considered as the point in time at which the handover should be considered as successfully completed for the first device 110 (i.e., the source IAB donor). In some example embodiments, the receipt of the indication for releasing the context associated with the third device may also be considered as the point in time at which the context of the connected terminal device and the child IAB node may be released in the first device 110.

[0074] In this way, the signaling overhead for handover of IAB nodes can be significantly reduced.

[0075] Figure 3 is a flow chart of an example method 300 implemented at a device according to some example embodiments of the present disclosure. For the purpose of discussion, the method 300 will refer to Figure 1 Described from the perspective of the first device 110 .

[0076] In 310 , the first device 110 sends a request message for handover of the third device 130 from the first device 110 to the second device 120 to the second device 120 , the request message including a first cell configuration of the third device 130 associated with the first device 110 .

[0077] In 320 , the first device 110 receives a response message confirming the request from the second device, the response message including a resource configuration for a connection between the third device and the second device and a second cell configuration of the third device associated with the second device.

[0078] In some example embodiments, the first cell configuration may include an identifier of at least one original cell to be removed from the third device during the handover.The second cell configuration includes an identifier of at least one new cell provided by the third device after the handover is completed.

[0079] In some example embodiments, the second cell configuration is different from the first cell configuration.

[0080] In 330, the first device 110 sends the resource configuration to the third device 130. The resource configuration is transmitted via an RRC reconfiguration message.

[0081] In some example embodiments, the first device 110 sends the second cell configuration having the resource configuration to the third device 130 .

[0082] In some example embodiments, if the first device receives an indication message indicating that the handover is successful, the first device may determine at least one available cell as a potential target cell for further handover to the second device.

[0083] In some example embodiments, the indication message may further include an indication for the first device to release the context associated with the third device.

[0084] Figure 4 is a flow chart of an example method 400 implemented at a device according to some example embodiments of the present disclosure. For the purpose of discussion, the method 400 will refer to Figure 1 Described from the perspective of the second device 120.

[0085] In 410 , the second device 120 receives, from the first device, a request message for a third device to switch from the first device to the second device, the request including a first cell configuration of the third device associated with the first device.

[0086] In 420 , the second device 120 sends a response message confirming the request, the response message including a resource configuration for a connection between the third device and the second device and a second cell configuration of the third device associated with the second device.

[0087] In some example embodiments, the second cell configuration is different from the first cell configuration.

[0088] In 430 , the second device 120 receives a message from the third device 130 indicating that a connection between the third device 130 and the second device 120 has been successfully established.

[0089] In some example embodiments, the first cell configuration may include an identifier of at least one original cell to be removed from the third device during the handover.The second cell configuration includes an identifier of at least one new cell provided by the third device after the handover is completed.

[0090] In some example embodiments, if second device 120 receives a message from third device 130 indicating that a connection between third device 130 and second device 120 has been successfully established, second device 120 removes at least one original cell to be removed from the third device from the set of potential target cells for further switching to the first device based on the first cell configuration.

[0091] In some example embodiments, second device 120 sends an indication message to first device 110 indicating that the switching is successful.

[0092] In some example embodiments, the second device 120 may send an indication to the first device 110 to release the context associated with the third device 130 .

[0093] In some example embodiments, the second device 120 may receive a confirmation from the third device 130 that the second cell configuration is adopted.

[0094] Figure 5 is a flow chart of an example method 500 implemented at a device according to some example embodiments of the present disclosure. For the purpose of discussion, the method 500 will refer to Figure 1 Described from the perspective of the third device 130.

[0095] In 510 , the third device 130 receives, from the first device, a resource configuration for a connection between the third device and the second device.

[0096] In 520 , the third device 130 establishes a connection based at least on the resource configuration.

[0097] In 530, the third device 130 sends a message to the second device indicating that the connection has been successfully established, so that the second device 120 removes at least one original cell to be removed from the third device 130 from the set of potential target cells for further switching to the first device 110 based on the first cell configuration of the third device 130 associated with the first device 110.

[0098] In some example embodiments, the third device 130 may also receive a second cell configuration of the third device associated with the second device using the resource configuration.

[0099] In some example embodiments, the second cell configuration may be different from a first cell configuration of a third device associated with the first device.

[0100] In some example embodiments, the third device 130 may send a confirmation to the second device 120 of adopting the second cell configuration.

[0101] In some example embodiments, an apparatus capable of executing any of the methods 300 (e.g., the first device 110) may include a component for executing the corresponding steps of the method 300. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module.

[0102] In some example embodiments, the apparatus includes: a component for sending a request message from a first device to a second device for a third device to switch from the first device to the second device, the request message including a first cell configuration of the third device associated with the first device; a component for receiving a response message from the second device confirming the request, the response message including a resource configuration for a connection between the third device and the second device and a second cell configuration of the third device associated with the second device; a component for sending the resource configuration to the third device; and a component for determining, in response to receiving an indication message from the second device indicating a successful switch, at least one available cell as a potential target cell for further switching to the second device based on the second cell configuration.

[0103] In some example embodiments, an apparatus capable of executing any of the methods 400 (e.g., the second device 120) may include a component for executing the corresponding steps of the method 400. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module.

[0104] In some example embodiments, the apparatus includes: a component for receiving a request message from a first device for a third device to switch from the first device to a second device, the request message including a first cell configuration of the third device associated with the first device; a component for sending a response message confirming the request, the response message including a resource configuration for a connection between the third device and the second device and a second cell configuration of the third device associated with the second device; a component for removing at least one original cell to be removed from the third device from a set of potential target cells for further switching to the first device based on the first cell configuration in response to receiving a second message from the third device indicating that a connection between the third device and the second device has been successfully established; and a component for sending an indication message to the first device indicating that the switching is successful.

[0105] In some example embodiments, an apparatus capable of executing any method 500 (e.g., third device 130) may include a component for executing the corresponding steps of method 500. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module.

[0106] In some example embodiments, the apparatus includes: a component for receiving, at a third device, a resource configuration for a connection between a third device and a second device from a first device; a component for establishing a connection based at least on the resource configuration; and a component for sending a second message to the second device indicating that the connection has been successfully established, so that the second device removes at least one original cell to be removed from the third device from a set of potential target cells for further switching to the first device based on the first cell configuration of the third device associated with the first device.

[0107] Figure 6 is a simplified block diagram of a device 600 suitable for implementing embodiments of the present disclosure. The device 600 may be provided to implement a communication device, such as Figure 1 The first device 110, the second device 120, and the third device 130 are shown. As shown, the device 600 includes one or more processors 610, one or more memories 620 coupled to the processors 610, and one or more communication modules 640 coupled to the processors 610.

[0108] The communication module 640 is used for two-way communication. The communication module 640 has at least one antenna to facilitate communication. The communication interface may represent any interface necessary to communicate with other network elements.

[0109] Processor 610 may be of any type suitable for the local technology network and may include one or more of the following: 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 as non-limiting examples. Device 600 may have multiple processors, such as application specific integrated circuit chips that are time slaved to a clock synchronized with a main processor.

[0110] The memory 620 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) 624, electrically programmable read-only memory (EPROM), flash memory, hard disks, compact disks (CDs), digital video disks (DVDs), and other magnetic storage devices and / or optical storage devices. Examples of volatile memories include, but are not limited to, random access memory (RAM) 622 and other volatile memories that do not persist over the duration of a power outage.

[0111] Computer program 630 includes computer executable instructions executed by associated processor 610. Program 630 may be stored in ROM 624. Processor 610 may perform any suitable actions and processes by loading program 630 into RAM 622.

[0112] The embodiments of the present disclosure can be implemented with the help of program 630, so that the device 600 can execute the reference Figures 2 to 5 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.

[0113] In some example embodiments, the program 630 may be tangibly embodied in a computer-readable medium that may be included in the device 600 (such as the memory 620) or in other storage devices accessible by the device 600. The device 600 may load the program 630 from the computer-readable medium to the RAM 622 for execution. The computer-readable medium may include any type of tangible non-volatile storage device, such as a ROM, EPROM, flash memory, hard disk, CD, DVD, etc. Figure 7 An example of a computer readable medium 700 in the form of a CD or DVD is shown. The computer readable medium has a program 630 stored thereon.

[0114] In general, various embodiments of the present disclosure may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in 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 is to be understood that the boxes, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers, or other computing devices, or some combination thereof as non-limiting examples.

[0115] 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 those included in a program module executed in a device on a target real or virtual processor, to perform the above-referenced Figure 3 , 45 and 6. Generally, 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 functionality 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 local and remote storage media.

[0116] The program code for performing the method of the present disclosure 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 when executed by the processor or controller, the program code enables the functions / operations specified in the flow chart and / or block diagram to be implemented. 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.

[0117] 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 the above-mentioned various processes and operations. Examples of carriers include signals, computer-readable media, etc.

[0118] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or apparatuses, or any suitable combination of the foregoing. More specific examples of computer readable storage media would include an electrical connection with one or more wires, a portable computer 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.

[0119] Further, although the operation is depicted in a particular order, this should not be understood as requiring that such operation be performed in the particular order shown or in a sequential order, or that all illustrated operations are performed, to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, although a plurality of specific implementation details are included in the above discussion, these should not be interpreted as limitations on the scope of the present disclosure, but should be interpreted as 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 a single embodiment in combination. On the contrary, the various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or according to any suitable subcombination.

[0120] Although the disclosure has been described in language specific to structural features and / or methodological acts, it is to be understood that the disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A method performed by a source integrated access and backhaul IAB donor device, and the method comprises: sending a request message for handover of an IAB node from the source IAB donor device to the target IAB donor device to a target IAB donor device, the request message comprising a first cell configuration of the IAB node associated with the source IAB donor device, the first cell configuration comprising an identifier of at least one original cell to be removed from the IAB node during the handover; as well as receiving a response message confirming the request message from the target IAB donor device, the response message including a resource configuration for a connection between the IAB node and the target IAB donor device, and a second cell configuration of the IAB node associated with the target IAB donor device, the second cell configuration including an identifier of at least one new cell to be provided by the IAB node after completion of the handover, the second cell configuration being different from the first cell configuration; as well as The resource configuration and the second cell configuration are sent to the IAB node via a radio resource control reconfiguration message.

2. The method according to claim 1, further comprising: In response to receiving an indication message indicating a handover success from the target IAB donor device, at least one available cell is determined as a potential target cell for further handover to the target IAB donor device based on the second cell configuration. 3 . The method according to claim 2 , wherein the indication message comprises an indication for the source IAB donor device to release a context associated with the IAB node. 4 .

4. A method performed by a target IAB donor device, and comprising: receiving, from a source IAB donor device, a request message for handover of an IAB node from the source IAB donor device to the target IAB donor device, the request message comprising a first cell configuration of the IAB node associated with the source IAB donor device, the first cell configuration comprising an identifier of at least one original cell to be removed from the IAB node during the handover; as well as sending a response message confirming the request message, the response message including a resource configuration for a connection between the IAB node and the target IAB donor device, and a second cell configuration of the IAB node associated with the target IAB donor device, the second cell configuration including an identifier of at least one new cell to be provided by the IAB node after completion of the handover, the second cell configuration being different from the first cell configuration; as well as A message is received from the IAB node indicating that a connection between the IAB node and the target IAB donor device has been successfully established.

5. The method according to claim 4, further comprising: In response to receiving the request message from the IAB node, at least one original cell to be removed from the IAB node is removed from a set of potential target cells for further handover to the source IAB donor device based on the first cell configuration.

6. The method according to claim 4, further comprising: An indication message indicating that the switching is successful is sent to the source IAB donor device.

7. The method according to claim 6, wherein sending the indication message comprises: An indication is sent for the source IAB donor device to release a context associated with the IAB node.

8. The method according to claim 4, further comprising: A confirmation of adopting the second cell configuration is received from the IAB node.

9. A source IAB donor 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, with the at least one processor, cause the source IAB donor device to at least: sending a request message for handover of an IAB node from the source IAB donor device to the target IAB donor device to a target IAB donor device, the request message comprising a first cell configuration of the IAB node associated with the source IAB donor device, the first cell configuration comprising an identifier of at least one original cell to be removed from the IAB node during the handover; as well as receiving a response message confirming the request message from the target IAB donor device, the response message including a resource configuration for a connection between the IAB node and the target IAB donor device, and a second cell configuration of the IAB node associated with the target IAB donor device, the second cell configuration including an identifier of at least one new cell to be provided by the IAB node after completion of the handover, the second cell configuration being different from the first cell configuration; as well as The resource configuration and the second cell configuration are sent to the IAB node via a radio resource control reconfiguration message.

10. The source IAB donor device of claim 9, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the source IAB donor device to at least: In response to receiving an indication message indicating a handover success from the target IAB donor device, at least one available cell is determined as a potential target cell for further handover to the target IAB donor device based on the second cell configuration. 11 . The source IAB donor device according to claim 10 , wherein the indication message comprises an indication for the source IAB donor device to release a context associated with the IAB node.

12. A target IAB donor 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, with the at least one processor, cause the target IAB donor device to at least: receiving, from a source IAB donor device, a request message for handover of an IAB node from the source IAB donor device to the target IAB donor device, the request message comprising a first cell configuration of the IAB node associated with the source IAB donor device, the first cell configuration comprising an identifier of at least one original cell to be removed from the IAB node during the handover; as well as sending a response message confirming the request message, the response message including a resource configuration for a connection between the IAB node and the target IAB donor device, and a second cell configuration of the IAB node associated with the target IAB donor device, the second cell configuration including an identifier of at least one new cell to be provided by the IAB node after completion of the handover, the second cell configuration being different from the first cell configuration; as well as A message is received from the IAB node indicating that a connection between the IAB node and the target IAB donor device has been successfully established.

13. The target IAB donor device of claim 12, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the source IAB donor device to at least: In response to receiving the message from the IAB node, at least one original cell to be removed from the IAB node is removed from a set of potential target cells for further handover to the source IAB donor device based on the first cell configuration.

14. The target IAB donor device of claim 12, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the source IAB donor device to at least: An indication message indicating that the switching is successful is sent to the source IAB donor device.

15. The target IAB donor device according to claim 14, wherein sending the indication message comprises: An indication is sent for the source IAB donor device to release a context associated with the IAB node.

16. The target IAB donor device of claim 12, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the source IAB donor device to at least: A confirmation of adopting the second cell configuration is received from the IAB node.

Images