Inter-host topology adaptation in self-access backhaul networks

Abstract

Methods, systems, and devices for inter-host topology adaptation in an access backhaul (IAB) network are described. An example method for wireless communication includes: sending a first message by a source host, the first message including an indication that a migration IAB node is configured to perform an inter-host handover operation; and receiving a second message including feedback information, wherein the source host is communicatively connected to the migration IAB node and a plurality of nodes located downstream of the migration IAB node.

Description

Technical Field

[0001] This document relates generally to wireless communications. Background Art

[0002] Wireless communication technology is driving the world towards an increasingly connected and networked society. The rapid growth of wireless communications and technological advances have led to greater demands for capacity and connectivity. Other aspects such as energy consumption, device cost, spectrum efficiency, and latency are also important to meet the needs of various communication scenarios. Compared with existing wireless networks, the next generation of systems and wireless communication technologies will provide support for self-access backhaul networks. Summary of the invention

[0003] The present invention relates to methods, systems and devices for inter-host topology adaptation in self-access backhaul networks in mobile communication technologies, including fifth generation (5G) and new radio (NR) communication systems.

[0004] In one exemplary aspect, a wireless communication method is disclosed. The method includes: sending, by a source host, a first message including an indication indicating that a migration from an access backhaul (IAB) node is configured to perform an inter-host handover operation; and receiving a second message including feedback information, wherein the source host is communicatively connected to the migration IAB node and a plurality of nodes downstream of the migration IAB node.

[0005] In another exemplary aspect, a wireless communication method is disclosed. The method includes receiving, by a migration self access backhaul (IAB) node, a first message from a source host, the first message including an indication indicating that the migration IAB node is configured to perform an inter-host handover operation; and sending a second message to at least one child node of the migration IAB node, the second message including the indication, wherein the source host is communicatively connected to the migration IAB node and a plurality of nodes located downstream of the migration IAB node.

[0006] In yet another exemplary aspect, the above method is embodied in the form of executable code by a processor and stored in a computer-readable program medium.

[0007] In yet another exemplary aspect, a device is disclosed, the device being configured or operable to perform the above method.

[0008] The above and other aspects and embodiments thereof are described in greater detail in the drawings, the description and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 An example of an IAB network is shown.

[0010] Figure 2 An example topology of an IAB network with multiple downstream nodes is shown.

[0011] Figure 3 An example of a method for wireless communication is shown.

[0012] Figure 4 Another example for wireless communication is shown.

[0013] Figure 5 is a block diagram representation of a portion of an apparatus that can be used to implement the methods and techniques of the presently disclosed technology. DETAILED DESCRIPTION

[0014] Compared to Long Term Evolution (LTE) systems, emerging 5G and NR systems have larger available bandwidth, support for massive MIMO, and use of multi-beam (e.g., beamforming) technology, which enables support and capabilities for integrated access and backhaul (IAB) links.

[0015] Examples from the 3GPP New Radio (NR) network architecture and 5G protocols are used herein only to aid understanding, and the disclosed techniques and embodiments may be practiced in other wireless systems that use communication protocols other than the 3GPP protocols.

[0016] Wireless backhaul links and relay links enable flexible deployment of dense NR cell networks without the need to increase the dense deployment of conventional transmission network elements. Figure 1 An example of a network with an IAB link is shown. As shown therein, nodes A (101), B (102) and C (103) are access nodes, and user equipment (UE 111, 112 and 113) can communicate with access nodes A, B and C through access links. However, there is a wired connection only between access node A and the core network, and there is no wired connection between access nodes B and C and core network elements. An access node (e.g., 102 or 103) that supports wireless access of UE and wirelessly transmits data is called an IAB node, and an access node (e.g., 101) that provides wireless backhaul function for the IAB node so that the UE can connect to the core network is called an IAB donor. Therefore, the access node can transmit UE data through the wireless backhaul link.

[0017] In one example, access node B may send data received from the UE to access node A via a wireless backhaul link, and then access node A sends the UE data to the core network element. For downlink, the core network element can send the UE data packet to access node A, and then access node A sends the UE data to access node B via the wireless backhaul link, and access node B sends the UE data via the access link. In some embodiments, the access link and the backhaul link may use the same carrier frequency. In other embodiments, the access link and the backhaul link may use different carrier frequencies. In some embodiments, the UE data may need to be transmitted through a multi-hop relay backhaul link between the access node and the core network.

[0018] In some embodiments, the access node may include a control unit (CU) and one or more distributed units (DU). In one example, the CU is a logical node that hosts the radio resource control (RRC), service data adaptation protocol (SDAP), and packet data convergence protocol (PDCP) of the access node, and the access node controls the operation of one or more DUs. The DU is a logical node that hosts the radio link control (RLC), medium access control (MAC), and physical (PHY) layers of the access node. The CU and the (one or more) DUs it controls are connected via the F1 interface. The F1 application protocol (F1-AP) is used to transmit low-level configuration information of the radio bearers between the CU and the DU, and to establish a GTP tunnel between the DU and the CU for each radio bearer. The CU / DU separation supported in NR is also supported in IAB deployments.

[0019] Figure 2 An example topology of an IAB node performing an inter-donor (or inter-CU) handover operation is shown. As shown therein, an inter-donor handover includes the migrating IAB node measuring a poor link quality, performing the measurement, and then sending a measurement report to the source donor (or original donor CU). At this point, the migrating IAB node has not yet determined whether it will perform an intra-CU migration or an inter-CU migration.

[0020] In some embodiments, after the original host CU receives the measurement report and decides to perform an inter-CU switching operation on the migration IAB node, one of the following two processes may be implemented.

[0021] Implementation 1: The original host CU is configured to send an RRC or F1-AP message to the child node of the migrated IAB node. In some embodiments, the message includes an indication of the parent node's intention to perform an inter-CU switching operation. If the child node intends to switch with the migrated IAB node, the child node replies with an RRC or F1AP message, and the message carries feedback information, which indicates consent to inter-CU switching. In some embodiments, the child node sends a measurement report to the original host CU (for example, in an RRC message). The original host CU then receives the RRC or F1-AP feedback message. If the feedback indicates consent to inter-CU switching, the original host CU is also configured to send subsequent RRC or F1-AP messages to the grandchild node of the migrated IAB node (i.e., the child node of the child node of the migrated IAB node) to determine whether the grandchild node wishes to follow the parent node to perform an inter-CU switching operation.

[0022] Implementation 2: In some embodiments, the original host CU sends an RRC or F1-AP message to the migration IAB node, and the message carries an instruction message indicating that the migration IAB node will perform inter-CU switching. Upon receiving the message from the original host CU, the migration IAB node constructs a backhaul adaptation protocol (BAP) control protocol data unit (PDU) or a medium access control (MAC) control element (CE). The control PDU or MAC CE is sent to the child nodes of the migration IAB node to inform them that their parent node is about to perform inter-CU migration. After the child node receives the BAP control PDU or MAC CE, and if they have determined to switch with the migration IAB node, each of those child nodes replies to the original host CU via an RRC or F1-AP message. The feedback message carries an indication of consent to participate in the inter-CU switching operation. In some embodiments, the child node sends a measurement report to the original host CU. At the same time, the child node constructs a BAP control PDU or MAC CE to inform any grandchild node in the migration IAB node that it wants to perform inter-CU switching.

[0023] In some embodiments, and after the original host CU collects all the IAB nodes and UEs to be switched, it sends a switching request to the target host CU. In one example, the switching request includes the Xn application protocol (Xn-AP) ID assigned by the original host CU to all MTs and UEs, the context information of each UE and the context information of each MT, the established backhaul (BH) RLC channel ID, and the BH RLC channel service quality (QoS) information. In some embodiments, the switching request may include the keys of all MTs and UEs (except the keys of the migrated IAB nodes to which the target host CU will assign new keys).

[0024] In some embodiments, and after receiving the handover request, the target host CU performs admission control. If the target host CU is able to support all IAB nodes and UEs to be switched, it replies to the original host CU with a handover request confirmation. On the other hand, if the target host CU can only accept a subset of IAB nodes and UEs, the target host CU sends a handover request confirmation message to the original host CU, which includes the target NG-RAN node UE XnAP ID (Target NG-RANnode UE XnAP ID) assigned to the MT and UE. In particular, the handover request confirmation message includes the XnAP ID (Source NG-RAN node UE XnAP ID) of the source NG-RAN node UE of the accepted IAB-MT and UE, an RRC reconfiguration message (RRC Reconfiguration message) sent to the migration IAB node, and an RRC reconfiguration message for the accepted downstream IAB node.

[0025] In some embodiments, the RRC reconfiguration message sent to the migrating IAB node includes:

[0026] - routing information;

[0027] - Backhaul (BH) RLC channel configuration;

[0028] - Migrate the IAB node IP address (if the IP address is generated by the target host);

[0029] - IP addresses used in the control plane domain;

[0030] -IP address used in the user plane domain;

[0031] - BAP address; and / or

[0032] -Target host CU CP IP address.

[0033] In some embodiments, the RRC reconfiguration message sent to the accepted downstream node includes:

[0034] - New key;

[0035] - routing information;

[0036] -BH RLC channel configuration;

[0037] - IP address (if the IP address is generated by the target host);

[0038] - IP addresses used in the control plane domain;

[0039] -IP address used in the user plane domain;

[0040] - BAP address; and / or

[0041] -Target host CU CP IP address.

[0042] The RRC reconfiguration message may include an indication of a message from the target host CU to prevent the IAB node from feeding back an RRC reconfiguration complete message to the original host CU.

[0043] In some embodiments, after receiving the handover request confirmation message, the original host CU sends an RRC reconfiguration message to the migration IAB node. If the confirmation message also includes an RRC reconfiguration message sent to downstream nodes and UEs, the original IAB node first sends the RRC reconfiguration message to these nodes and UEs, and finally sends the RRC reconfiguration message to the migration IAB node.

[0044] In some embodiments, after the migration IAB node successfully connects to the target host CU, the F1 establishment process is performed. After the migration IAB node F1 establishment is successful, the migration IAB node can serve the UE and the child nodes. However, at this time, one or more child nodes do not know that each of them should start the F1 establishment process.

[0045] In some embodiments, and after the migration IAB node F1 is successfully established, a BAP control PDU or MAC CE is constructed and sent to the child node. The PDU or MAC CE is used to indicate that the migration IAB node can serve the child node. If the child node has previously received an RRC reconfiguration message, after receiving the indication sent by the parent node, it returns an RRC reconfiguration complete message to the target host CU. If the IP address has been assigned to the child node through operations administration and maintenance (OAM), the child node also includes the IP address in the RRC reconfiguration complete message.

[0046] In some embodiments, after the target host CU sends an F1 SETUP RESPONSE to the migration IAB node, if an RRC reconfiguration message has not been sent to the child node before, and the key of the child node is obtained in the handover request message, the RRC reconfiguration message is sent to the child node using the key. In one example, the RRC reconfiguration message includes:

[0047] - New key;

[0048] - routing information;

[0049] -BH RLC channel configuration;

[0050] - IP address (if the IP address is generated by the target host);

[0051] - IP addresses used in the control plane domain;

[0052] -IP address used in the user plane domain;

[0053] - BAP address; and / or

[0054] -Target host CU CP IP address.

[0055] Embodiments of the disclosed technology also provide a method and system to determine which downstream nodes follow the migrating IAB node for inter-CU switching.

[0056] In some embodiments, it is assumed that the original host CU knows that the migrated IAB node will perform inter-CU handover, and also knows which downstream nodes and UEs the migrated IAB node is connected to. In these scenarios,

[0057] - If the downstream node is dual-connected, there is no need to perform inter-CU switching with the parent node, and therefore, the CU directly performs the secondary node change procedure to select a new parent node for the node.

[0058] - If the downstream node is singly connected, one of the following two procedures may be implemented.

[0059] Implementation 1: The migration IAB node informs the child node of the inter-CU switching operation through the BAP control PDU or MAC CE. In some embodiments, the child node sends a measurement report to the original host CU, and the original host CU switches the child node to another parent node. In other embodiments, the child node performs a re-establishment process to another parent node.

[0060] Implementation 2: The original host CU notifies the downstream node of the parent node CU handover through RRC or F1-AP message. If the downstream node does not follow the handover, the node may send a measurement report to the original host CU, and the original host CU switches the child node to another parent node. Alternatively, the node may perform a re-establishment process to another parent node.

[0061] Embodiments of the disclosed technology provide methods and systems for selecting a target host CU. In some embodiments, the original host CU sends a switching request to multiple host CUs based on a measurement report. After receiving one or more switching request confirmation messages, the original host CU uses the source NG-RAN node UE XnAP ID therein to determine the target host CU. In one example, the original host CU may select the host that accepts the most IAB nodes and UEs as the target host CU. For the selected target host CU, the switching of some IAB nodes may have been rejected. In this scenario, one of the following two processes may be implemented.

[0062] Implementation 1: If the original host CU has received the measurement reports of these rejected IAB nodes, it can instruct these IAB nodes to perform handover. If the original host CU has not received the measurement reports of these IAB nodes, these IAB nodes can report the measurement reports and then perform handover.

[0063] Implementation 2: The original host CU sends an RRC message to the rejected IAB node. The RRC message includes:

[0064] - Indicates why the (downstream) IAB node cannot be switched along with the parent node

[0065] - Information about supported IAB frequencies

[0066] - The cell ID of the currently registered public land mobile network (PLMN) that supports the IAB function;

[0067] - IAB-supported cell IDs in all PLMNs; and / or

[0068] -Cell Global Identity (CGI), Physical Cell Identifier (PCI), or CGI and PCI.

[0069] Figure 3 An example of a wireless communication method 300 for inter-host topology adaptation in an IAB network is shown. The method 300 includes, at operation 310, sending a first message by a source host, the first message including an indication indicating that a migrated self access backhaul (IAB) node is configured to perform an inter-host handover operation.

[0070] The method 300 includes, at operation 320 , receiving a second message including feedback information.

[0071] Figure 4 An example of another wireless communication method 400 for inter-host topology adaptation in an IAB network is shown. The method 400 includes, at operation 410, receiving a first message from a source host by a migrating access backhaul (IAB) node, the first message including an indication indicating that the migrating IAB node is configured to perform an inter-host handover operation.

[0072] The method 400 includes, at operation 410, sending a second message to at least one child node of the migration IAB node, the second message including the indication.

[0073] In some embodiments, the following technical solutions may be implemented:

[0074] A1. A method for wireless communication, comprising: sending a first message by a source host, the first message including an indication for indicating that a migration from an access backhaul (IAB) node is configured to perform an inter-host switching operation; and receiving a second message, the second message including feedback information, wherein the source host is communicatively connected to the migration IAB node and multiple nodes downstream of the migration IAB node.

[0075] A2. The method according to scheme A1, wherein the plurality of nodes include one or more IAB nodes.

[0076] A3. The method according to scheme A1 also includes: receiving a radio resource control (RRC) message from one of the multiple nodes, the RRC message including a measurement report.

[0077] A4. A method according to scheme A1, wherein the feedback information includes an indication for indicating that one of the multiple nodes intends to perform the inter-host switching operation.

[0078] A5. A method according to scheme A4, wherein the migration IAB node includes at least one mobile terminal (Mobile Termination, MT) for communicating with at least one UE, and wherein the method further includes: sending a first Xn application protocol (XnAP) message to a target host, the first XnAP message including an XnAP identifier and context information for each of the at least one MT, and an XnAP identifier and context information for each of the at least one UE.

[0079] A6. The method according to scheme A5, wherein the first XnAP message further includes a key allocated by the source host to each of the at least one MT and each of the at least one UE.

[0080] A7. The method according to scheme A5 or A6 also includes: receiving a second XnAP message from the target host, the second XnAP message including a first RRC reconfiguration message for at least one of the multiple nodes, and a second RRC reconfiguration message for the migration IAB node.

[0081] A8. A method according to scheme A7, wherein the first RRC reconfiguration message includes one or more of the following items: a new key for at least one of the multiple nodes, routing information, a backhaul (BH) radio link control (RLC) channel configuration, a backhaul adaptation protocol (BAP) address, one or more IP addresses, the IP address of the target host, an IP address used in a control plane domain, or an IP address used in a user plane domain.

[0082] A9. A method according to scheme A7, wherein the second RRC reconfiguration message includes one or more of the following items: routing information, backhaul (BH) radio link control (RLC) channel configuration, backhaul adaptation protocol (BAP) address, one or more IP addresses, the IP address of the target host, the IP address used in the control plane domain, or the IP address used in the user plane domain.

[0083] A10. A method according to any one of schemes A1 to A9, wherein the first message is sent to one or more nodes among the multiple nodes.

[0084] A11. A method according to any one of schemes A1 to A9, wherein the first message is sent to the migration IAB node.

[0085] A12. A method according to scheme A1, wherein the first message is sent to one of the multiple nodes, and wherein the first message also includes one or more of the following items: an indication of the reason why one of the multiple nodes cannot perform the inter-host switching operation, IAB frequency information, a cell ID supporting the IAB function under the currently registered public land mobile network (PLMN), multiple cell IDs supporting IAB in all PLMNs, a cell global identity (CGI), or a physical cell identity (PCI).

[0086] A13. A method according to any one of schemes A10 to A12, wherein the first message is a radio resource control (RRC) message or an F1 application protocol (F1AP) message.

[0087] A14. A method for wireless communication, comprising: receiving a first message by a migrating access backhaul (IAB) node from a source host, the first message including an indication for indicating that the migrating IAB node is configured to perform an inter-host switching operation; and sending a second message to at least one child node in the migrating IAB node, the second message including the indication, wherein the source host is communicatively connected to the migrating IAB node and a plurality of nodes located downstream of the migrating IAB node.

[0088] A15. A method according to scheme A14, wherein the indication informs the child node that the parent node of the child node intends to perform the inter-host switching operation.

[0089] A16. A message according to scheme A14 or A15, wherein the second message is a Backhaul Adaptation Protocol (BAP) control protocol data unit (PDU) or a Medium Access Control (MAC) control element.

[0090] A17. A wireless communication device comprises a processor and a memory, wherein the processor is configured to read a code from the memory and implement a method described in any one of schemes A1 to A16.

[0091] A18. A computer program product, comprising a computer-readable program medium code stored thereon, which, when executed by a processor, causes the processor to implement the method described in any one of embodiments A1 to A16.

[0092] In some embodiments, the following technical solutions may be implemented:

[0093] B1. A method for inter-host topology adaptation in wireless communications, comprising: sending a message by a source host to an IAB node; sending an XnAP message by the source host to a target host; receiving a message from the IAB node by the source host; receiving an XnAP message from a target host by the source host; sending a message by the target host to the IAB node; and receiving a message from the IAB node by the target host, wherein the source host is communicatively connected to the migration IAB node and multiple nodes, and wherein the multiple nodes include at least one user equipment (UE) downstream of the migration IAB node.

[0094] B2. The method according to solution B1, wherein the IAB node may be a migration IAB node or a downstream IAB node, and wherein the downstream IAB node may be a child node of the migration IAB node, or an IAB node whose UL data packet needs to be forwarded by the migration IAB node.

[0095] B3. The method according to solution B1, wherein the message from the source host to the IAB node may be an RRC or F1AP message, and the message from the IAB node to the source host may also be an RRC or F1AP message.

[0096] B4. According to the method of scheme B3, the message is sent from the source host to the IAB node, wherein the message includes an inter-host switching indication or a parent node inter-host switching indication.

[0097] B5. According to the method of scheme B3, after receiving the message, the IAB node shall construct a BAP PDU, or the IAB node shall generate the MAC control element, and then send the BAP PDU or MAC CE to all its child nodes, and wherein the BAP PDU or MAC CE indicates that the IAB node will perform inter-CU switching.

[0098] B6. According to the method of scheme B3, the message is sent from the IAB node to the source host, wherein the message includes an inter-host switching indication to inform the source host that the IAB node agrees to perform inter-CU switching.

[0099] B7. According to the method of scheme B3, the message is from the IAB node to the source host, wherein the message includes a measurement report.

[0100] B8. A method according to scheme B1, wherein the XnAP message from the source host to the target host includes one or more of the following items: the source NG-RAN node UE XnAP ID of the IAB node and all UEs connected to the IAB node, UE context information, IAB node mobile terminal (MT) context information, BH RLC channel information of the IAB node, and / or a key allocated by the source host CU to each of the at least one MT and each of the at least one UE.

[0101] B9. A method according to scheme B1, wherein the XnAP message from the target host to the source host includes one or more of the following items: the target NG-RAN node UEXnAP ID of the accepted IAB node and the accepted UE connected to the accepted IAB node, the source NG-RAN node UEXnAP ID of the accepted IAB node and the accepted UE connected to the accepted IAB node, an RRC message for the accepted IAB node, and / or an RRC message for the accepted UE, wherein the accepted IAB node or UE is an IAB node or UE whose QoS requirements can be accepted by the target host.

[0102] B10. A method according to scheme B9, wherein the RRC message for the downstream IAB node includes one or more of the following items: an indication indicating that the message comes from a target host, a new key for the IAB node MT, routing information, backhaul (BH) radio link control (RLC) channel configuration information, a backhaul adaptation protocol (BAP) address, or an IP address of the target host CU.

[0103] B11. A method according to scheme B9, wherein the RRC message used to migrate the IAB node includes one or more of the following items: routing information, backhaul (BH) radio link control (RLC) channel configuration information, backhaul adaptation protocol (BAP) address, or the IP address of the target host CU.

[0104] B12. The method according to scheme B9, wherein the RRC message for the IAB node includes an IP address, an IP address used in a control plane domain, and an IP address used in a user plane domain.

[0105] B13. According to the method of solution B1, after receiving the F1AP message from the target host, the IAB node shall construct a BAP PDU, or the IAB node shall generate the MAC control element, and then send the BAP PDU or MAC CE to all child nodes of the IAB node. The BAP PDU or MAC CE indicates that the IAB node can forward data.

[0106] B14. According to the method of solution B1, after sending the F1AP message to the IAB node, the target host should use the key previously received from the source host to send an RRC message to the child node of the IAB node.

[0107] B15. A method according to scheme B14, wherein the RRC message includes one or more of the following items: a new key, routing information, backhaul (BH) radio link control (RLC) channel configuration information, a backhaul adaptation protocol (BAP) address, or an IP address of the target host CU.

[0108] B16. A method according to scheme B14, wherein the RRC message includes an IP address, an IP address used in a control plane domain, and an IP address used in a user plane domain.

[0109] B17. According to the methods of schemes B13 and B14, the child node shall send an RRC reconfiguration completion message to the target host.

[0110] B18. According to the method of scheme B17, the RRC reconfiguration completion message includes an IP address, an IP address used in a control plane domain, and an IP address used in a user plane domain.

[0111] B19. A method according to scheme B1, wherein the message from the source host to the IAB node includes one or more of the following items: an indication of the reason why one of the multiple nodes cannot perform the inter-host switching operation, IAB frequency information, a cell ID supporting the IAB function under the currently registered public land mobile network (PLMN), multiple cell IDs supporting IAB in all PLMNs, a cell global identity (CGI), a physical cell identity (PCI), or the CGI and the PCI.

[0112] B20. A wireless communication device, comprising a processor and a memory, wherein the processor is configured to read a code from the memory and implement the method described in any one of schemes B1 to B19.

[0113] B21. A computer program product, comprising a computer-readable program medium code stored thereon, which, when executed by a processor, enables the processor to implement the method described in any one of embodiments B1 to B19.

[0114] Figure 5is a block diagram representation of a portion of an apparatus according to some embodiments of the presently disclosed technology. Apparatus 505, such as a base station or wireless device (or UE), may include processor electronics 510, such as a microprocessor that implements one or more of the techniques presented herein. Apparatus 505 may include transceiver electronics 515 for sending and / or receiving wireless signals through one or more communication interfaces (such as (one or more) antennas 520). Apparatus 505 may include other communication interfaces for sending and receiving data. Apparatus 505 may include one or more memories (not explicitly shown) configured to store information such as data and / or instructions. In some embodiments, processor electronics 510 may include at least a portion of transceiver electronics 515. In some embodiments, apparatus 505 is used to implement at least some of the disclosed techniques, modules, or functions.

[0115] Some embodiments described herein are described in the general context of methods or processes, which in one embodiment may be implemented by a computer program product contained in a computer-readable medium, which includes computer executable instructions, such as program code, executed by a computer in a networked environment. Computer-readable media may include removable and non-removable storage devices, including but not limited to read-only memory (ROM), random access memory (RAM), compact disc (CD), digital versatile discs (DVD), etc. Therefore, computer-readable media may include non-transitory storage media. Generally, program modules may include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. Computer or processor executable instructions, related data structures, and program modules represent examples of program codes for executing the steps of the methods disclosed herein. Specific sequences of such executable instructions or related data structures represent examples of corresponding actions for implementing the functions described in these steps or processes.

[0116] Some disclosed embodiments can be implemented as devices or modules using hardware circuits, software or a combination thereof. For example, a hardware circuit implementation may include discrete analog and / or digital components, for example, integrated as a part of a printed circuit board. Alternatively or additionally, the disclosed components or modules can be implemented as application specific integrated circuits (Application Specific Integrated Circuit, ASIC) and / or field programmable gate arrays (Field Programmable Gate Array, FPGA) devices. Some embodiments may additionally or alternatively include a digital signal processor (digital signal processor, DSP), which is a professional microprocessor with an architecture optimized for the operational requirements of digital signal processing associated with the disclosed functionality of the present application. Similarly, various components or subcomponents within each module may be implemented in software, hardware or firmware. The connection between the modules and / or the components within the modules may be provided using any of the connection methods and media known in the art, including but not limited to communication using appropriate protocols through the Internet, wired or wireless networks.

[0117] Although many details are included herein, these details should not be construed as limitations on the scope of the claimed invention or the scope of the invention that may be claimed, but should be construed as descriptions of features peculiar to a particular embodiment. Certain features described herein in the context of each embodiment can also be implemented in a single embodiment in combination. On the contrary, the various features described in the context of a single embodiment can also be implemented individually or in any suitable sub-combination in multiple embodiments. In addition, although features may be described above as working in some combinations, and even initially claimed as such, one or more features from the claimed combination can be removed from the combination in some cases, and the claimed combination may refer to a sub-combination or a variation of a sub-combination. Similarly, although operations are depicted in a particular order in the accompanying drawings, this should not be construed as requiring such operations to be performed in the illustrated particular order or in a continuous order, or requiring all operations shown to be performed to achieve desired results.

[0118] Only a few embodiments and examples are described, and other embodiments, improvements, and variations can be made based on what is described and illustrated in this disclosure.

Claims

1. A method for wireless communication, comprising: A first message is sent by a source host, the first message including an indication for indicating that a migration from access backhaul (IAB) node is configured to perform an inter-host handover operation; and receiving a second message, wherein the second message includes feedback information, wherein the source host is communicatively connected to the migrated from access backhaul (IAB) node and a plurality of nodes located downstream of the migrated from access backhaul (IAB) node; wherein the first message is sent to one or more of the plurality of nodes, or is sent to the migrated from access backhaul (IAB) node; wherein the feedback information includes an indication of an intention of one of the plurality of nodes to perform an inter-host handover operation, wherein the one of the plurality of nodes is a child node of the migrated self-access backhaul (IAB) node, and In response to receiving the indication of the child node's intention to perform the inter-host handover operation, sending a third message to a grandchild node, the third message including the indication of the child node's intention to perform the inter-host handover operation, wherein the grandchild node is a child node of the child node of the migration IAB node; and A fourth message is received, the fourth message including an indication of the grandchild node's intent to perform the inter-host handover operation.

2. The method according to claim 1, wherein: The plurality of nodes include one or more independent access backhaul (IAB) nodes.

3. The method according to claim 1, further comprising: A radio resource control (RRC) message is received from a node among the plurality of nodes, the radio resource control (RRC) message including a measurement report.

4. The method according to claim 1, wherein: The migrated from access backhaul (IAB) node comprises at least one mobile terminal (MT) for communicating with at least one UE, and wherein the method further comprises: A first Xn application protocol (XnAP) message is sent to a target host, wherein the first Xn application protocol (XnAP) message includes an Xn application protocol (XnAP) identifier and context information for each mobile terminal (MT) in the at least one mobile terminal (MT), and an Xn application protocol (XnAP) identifier and context information for each UE in the at least one UE.

5. The method according to claim 4, wherein: The first Xn Application Protocol (XnAP) message also includes a key allocated by the source host to each of the at least one mobile terminal (MT) and each of the at least one UE.

6. The method according to claim 4 or 5, further comprising: A second Xn application protocol (XnAP) message is received from the target host, wherein the second Xn application protocol (XnAP) message includes: a first radio resource control (RRC) reconfiguration message for at least one of the multiple nodes, and a second radio resource control (RRC) reconfiguration message for the migrated access backhaul (IAB) node.

7. The method according to claim 6, wherein: The first radio resource control (RRC) reconfiguration message includes one or more of the following items: a new key for at least one of the multiple nodes, routing information, a backhaul (BH) radio link control (RLC) channel configuration, a backhaul adaptation protocol (BAP) address, one or more IP addresses, an IP address of the target host, an IP address used in a control plane domain, or an IP address used in a user plane domain.

8. The method according to claim 6, wherein: The second radio resource control (RRC) reconfiguration message includes one or more of the following items: routing information, backhaul (BH) radio link control (RLC) channel configuration, backhaul adaptation protocol (BAP) address, one or more IP addresses, the IP address of the target host, the IP address used in the control plane domain, or the IP address used in the user plane domain.

9. The method according to claim 1, wherein: The first message is sent to one of the multiple nodes, and the first message further includes one or more of the following items: an indication of a reason why one of the multiple nodes cannot perform the inter-host switching operation, independent access backhaul (IAB) frequency information, a cell ID supporting the independent access backhaul (IAB) function under a currently registered public land mobile network (PLMN), multiple cell IDs supporting independent access backhaul (IAB) in all public land mobile networks (PLMNs), a cell global identity (CGI), or a physical cell identity (PCI).

10. The method according to claim 1 or 9, wherein: The first message is a Radio Resource Control (RRC) message, or a F1 Application Protocol (F1AP) message.

11. A method for wireless communication, comprising: Receiving, by a migrating from access backhaul (IAB) node, a first message from a source host, the first message comprising an indication indicating that the migrating from access backhaul (IAB) node is configured to perform an inter-host handover operation; and sending a second message to at least one child node of the migrated self access backhaul (IAB) node, the second message including the indication, wherein the second message including the indication causes the child node to send feedback information to the source host, wherein the feedback information includes an indication of the child node's intention to perform the inter-host switching operation; wherein the source host is communicatively connected to the migration-from access backhaul (IAB) node and a plurality of nodes located downstream of the migration-from access backhaul (IAB) node, wherein the feedback information causes the source host to send a third message to a grandchild node, the third message including an indication of the child node's intention to perform the inter-host switching operation, wherein the grandchild node is a child node of the child node of the migration IAB node, The third message causes the grandchild node to send a fourth message, wherein the fourth message includes an indication of the grandchild node's intention to perform the inter-host switching operation.

12. The method according to claim 11, wherein: The indication informs the child node that the parent node of the child node intends to perform the inter-host switching operation.

13. The method according to claim 11 or 12, wherein: The second message is a Backhaul Adaptation Protocol (BAP) control protocol data unit (PDU) or a Medium Access Control (MAC) control element.

14. A wireless communication device, comprising a processor and a memory, wherein: The processor is configured to read the code from the memory and execute the method according to any one of claims 1 to 13.

15. A computer program product comprising computer readable program medium code stored thereon, said code, when executed by a processor, causing said processor to perform the method according to any one of claims 1 to 13.

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