Method and system for implementing mobility operations in an integrated access and backhaul system - Patents.com

Abstract

A method and system for implementing mobility operations in an integrated access and backhaul system is provided. A method, apparatus, and system for determining whether a handover between network nodes should occur, and a method for implementing the handover. The present disclosure relates to, among other things, mechanisms for implementing mobility within an IAB network by exchanging information such as mobility configuration information and mobility assistance information.

Description

[Technical field]

[0001] TECHNICAL FIELD This disclosure is directed generally to wireless communications. [Background technology]

[0002] Mobile communication technologies are moving the world towards an increasingly connected and networked society. The rapid growth of mobile communications and technological advances have led to further demand 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. Various techniques are being discussed, including new methods to provide higher quality of service, longer battery life, and improved performance. Summary of the Invention [Means for solving the problem]

[0003] This patent document describes, among other things, techniques for communicating in an integrated access and backhaul (IAB) deployment for new radio (NR).

[0004] The following aspects may be preferably implemented in various embodiments.

[0005] In one aspect, a first integrated and access backhaul (IAB) network node transmits mobility configuration information to one or more child nodes or one or more wireless devices, the mobility configuration information being usable for mobility.

[0006] In one aspect, a network node receives mobility assistance information from one or more wireless devices and determines whether to perform a transition of the one or more wireless devices. In an aspect, the wireless device is a UE or an IAB node. In yet another aspect, the mobility configuration information comprises (a) an indication information related to whether a parent node has performed or will perform an inter-CU transition, or (b) an indication information related to whether an ancestor node has performed or will perform an inter-CU transition, or (c) an indication information related to initiating a measurement, or (d) a measurement configuration. In yet another aspect, the mobility assistance information comprises (a) a measurement result, or (b) a group mobility indication, or (c) a group mobility interest, or (d) a group mobility intent, or (e) a mobility type, or (f) information about a target cell, or (g) information about a candidate cell. In yet another aspect, the mobility assistance information is received via a radio resource control (RRC) message, or via a BAP sublayer, or via a MAC sublayer.

[0007] In one aspect, the wireless device or network node transmits mobility assistance information to an IAB donor CU, the mobility assistance information being usable for mobility. In yet another aspect, the mobility assistance information comprises (a) measurement results, or (b) group mobility indication, or (c) group mobility interest, or (d) group mobility intent, or (e) mobility type, or (f) information about the target cell, or (g) information about the candidate cell. In another aspect, the mobility type comprises group mobility, or inter-CU transition, or inter-DU transition, or intra-CU transition, or intra-DU transition.

[0008] In one aspect, the network node receives a measurement threshold via a radio resource control (RRC) message transmitted from the IAB donor CU, performs measurements of the serving cell, and if the measured result is lower than the measurement threshold, the network node transmits a mobility configuration to the child node or wireless device, or the network node transmits mobility assistance information to the IAB donor CU. In yet another aspect, the measurement threshold is an RSRP threshold based on SS / PBCH blocks or based on CSI-RS. In yet another aspect, the mobility configuration information comprises (a) indication information related to whether a parent network node has performed or will perform an inter-CU transition, or (b) indication information related to whether an ancestor node has performed or will perform an inter-CU transition, or (c) indication information related to initiating a measurement, or (d) a measurement configuration. In yet another aspect, the network node transmits the mobility configuration to the child node or wireless device (a) via the BAP sublayer or (b) via the MAC CE. In yet another aspect, the mobility assistance information comprises (a) measurement results, or (b) group mobility indication, or (c) group mobility interest, or (d) group mobility intent, or (e) mobility type, or (f) information regarding a target cell, or (g) information regarding a candidate cell.

[0009] In an aspect, the first base station transmits a mobility related request message to a second base station, the base station being an eNB or a donor CU or a gNB, and receives a mobility related ACK message from the second base station. In yet another aspect, prior to transmitting the mobility related message to the second base station, the first base station receives a mobility related request message from a third base station, the base station being an eNB or a donor CU or a gNB. In yet another aspect, the mobility related request message is a handover request message or an SgNB addition request message. In yet another aspect, the mobility related ACK message is a handover request acknowledgement message or an SgNB addition request acknowledgement message. In yet another aspect, the mobility related request message is an SgNB change request message. In yet another aspect, the donor CU configures (a) a BH RLC channel, (b) a BAP sub-layer routing entry on a target path between the target parent IAB node and the target IAB donor DU, or (c) a UL traffic mapping for the target path, or (d) a DL mapping on the target IAB donor DU.In yet another aspect, the mobility related request or mobility related request message may include a group mobility interest, or a group mobility indication, or a mobile IAB node indication, or an IAB node indication, or information related to group mobility authorization, or user equipment (UE) context information for one or more UEs or IAB-MTs, or a BAP address of an IAB node allocated by the source donor CU, or a BH RLC channel configuration for an IAB-MT configured by the source donor CU, or a BH RLC channel ID, or a QoS, CP traffic type, or an RLC mode for a collocated IAB-DU configured by the source donor CU. The information includes an RLC channel configuration, or configuration information of the collocated IAB-DU, or a routing configuration for the collocated IAB-DU configured by the source donor CU, or a traffic mapping configuration for the collocated IAB-DU configured by the source donor CU, or a BAP routing ID and a BAP address of an IAB node along the corresponding path configured by the source donor CU, or a path ID and a BAP address of an IAB node along the corresponding path configured by the source donor CU, or a gNB-DU UE F1AP ID, or PDCP information, or an identification of the DU serving the UE / IAB-MT, or its DU ID, and / or a gNB ID of the source donor CU, including its BAP address.

[0010] In yet another aspect, the configuration information of the collocated IAB-DU comprises IP address request information including an IP address request or an IPV4 address request number or an IPv6 address request number or an IPv6 prefix request, or updated DU served cell information including a DU ID, or a PCI or CGI or PLMN ID list. In yet another aspect, the mobility related ACK message comprises a group mobility indication, or an RRC reconfiguration message for one or more UEs or IAB-MTs, or collocated IAB-DU configuration information, or routing configuration information configured by the second base station, or traffic mapping configuration information configured by the second base station, or indication information indicating routing configuration information or traffic mapping configuration information applicable on the target path. In yet another aspect, the collocated IAB-DU configuration information comprises updated DU served cell information including an IP address, or an IP address prefix, or an IP address usage, or an allocated IP address information for the IAB-DU comprising an IAB donor DU BAP address, or an IP address of a target donor CU, or a reconfigured DU ID for the collocated IAB-DU, or a PCI or CGI or PLMN ID list.

[0011] In yet another aspect, after receiving a mobility related message from the first base station, at the second base station, an F1 configuration request message is received from the IAB node, where the F1 AP message includes a gNB ID of the source donor CU.

[0012] In yet another aspect, sending an F1AP message to an IAB node at the second base station after receiving a mobility related message from the first base station, the message including a plurality of gNB-DU UE F1AP IDs, or UL UP TNL information, or new UL UP TNL information, or BH information, or an old TNL address of the gNB-CU, or a new TNL address of the gNB-CU, or a source F1AP UE context release indication, or a CU change indication, or an inter-donor transition indication, the F1AP message being a UE context setup request message, or a UE context modification request message, or an IAB UP configuration update request message, or a new F1AP message. In yet another aspect, sending a UE context release message to the first base station at the second base station after sending a mobility related ACK message to the first base station, the UE context release message including a plurality of pairs of source / target NG-RAN node UE XnAP IDs, or a plurality of pairs of old and new eNB UE X2AP IDs. In yet another aspect, after receiving a mobility related ACK message from the second base station, at the first base station, sending a message to the second base station, the message including SN status information for the plurality of UEs / IAB-MTs, or a plurality of pairs of source and / or target NG-RAN node UE XnAP IDs, or a plurality of pairs of old and new eNB UE X2AP IDs.

[0013] In one aspect, the PDCP information is received at the target network node, and the target network node performs (a) decryption using the received PDCP information, or (b) header recovery using the received PDC information, or (c) integrity verification using the received PDCP information. In yet another aspect, before receiving the PDCP information, the target network node transmits PDCP configuration request information to the source network node, the PDCP configuration request information including a PDCP key request indication or a PDCP key indication. In yet another aspect, the PDCP information includes ciphering related information, or integrity related information, or a hyperframe number (HFN), or header compression related information. In yet another aspect, the network node is a donor CU or an IAB node. In yet another aspect, the wireless device is a user equipment (UE) and the child node is an IAB node. In yet another aspect, the network node is a donor CU.

[0014] In aspects of the present disclosure, transmission and reception of messages is performed by various devices, including MTs, UEs, IAB nodes (eg, access, transition, descendant, or ancestor), and IAB donors.

[0015] These and other aspects are described in this disclosure. For example, the present application provides the following: (Item 1) 1. A method for transmitting information, comprising: Transmitting mobility configuration information at an integrated and access backhaul (IAB) network node to one or more child nodes or one or more wireless devices, the mobility configuration information being usable for mobility purposes. A method comprising: (Item 2) 1. A method for transmitting information, comprising: receiving, at a network node, mobility assistance information from one or more wireless devices, the wireless devices being user equipment (UE) or IAB nodes; A method comprising: (Item 3) The method of claim 1, wherein the mobility configuration information comprises: (a) indication information related to whether a parent node is performing or will perform an inter-CU transition; or (b) indication information related to whether an ancestor node is performing or will perform an inter-CU transition; or (c) indication information related to initiating measurements; or (d) a measurement configuration. (Item 4) The method of claim 2, wherein the mobility assistance information comprises (a) measurement results, or (b) group mobility indication, or (c) group mobility interest, or (d) group mobility intent, or (e) mobility type, or (f) information regarding a target cell, or (g) information regarding a candidate cell. (Item 5) The method according to item 2, wherein the mobility assistance information is received via a radio resource control (RRC) message, or via a BAP sublayer, or via a MAC sublayer. (Item 6) 1. A method for transmitting information, comprising: transmitting, at a wireless device or network node, mobility assistance information to an IAB network node, the mobility assistance information being usable for mobility purposes; A method comprising: (Item 7) The method of claim 6, wherein the mobility assistance information comprises (a) measurement results, or (b) group mobility indication, or (c) group mobility interest, or (d) group mobility intent, or (e) mobility type, or (f) information regarding a target cell, or (g) information regarding a candidate cell. (Item 8) 8. The method of claim 7, wherein the mobility type comprises group mobility, or inter-CU migration, or inter-DU migration, or intra-CU migration, or intra-DU migration. (Item 9) 1. A method for transmitting information, comprising: receiving, at a network node, a measurement threshold via a Radio Resource Control (RRC) message sent from an IAB donor CU; performing a serving cell measurement in the network node, and if the measured result is lower than the measurement threshold, the network node sends a mobility configuration to a child node or a wireless device, or the network node sends mobility assistance information to the IAB donor CU; A method comprising: (Item 10) 10. The method according to claim 9, wherein the measurement threshold is an RSRP threshold based on SS / PBCH blocks or based on CSI-RS. (Item 11) The method of claim 9, wherein the mobility configuration information comprises (a) indication information related to whether a parent network node has performed or will perform an inter-CU transition, or (b) indication information related to whether an ancestor node has performed or will perform an inter-CU transition, or (c) indication information related to initiating measurements, or (d) a measurement configuration. (Item 12) Item 12. The method of item 11, wherein the network node transmits the mobility configuration to the child node or the wireless device (a) via a BAP sublayer and (b) via a MAC CE. (Item 13) The method of claim 9, wherein the mobility assistance information comprises (a) measurement results, or (b) group mobility indication, or (c) group mobility interest, or (d) group mobility intent, or (e) mobility type, or (f) information regarding a target cell, or (g) information regarding a candidate cell. (Item 14) 1. A method for transmitting information, comprising: Sending, at a first base station, a mobility related request message to a second base station, where the base station is an eNB or a donor CU or a gNB; receiving, at the first base station, a mobility-related ACK message from the second base station; A method comprising: (Item 15) receiving a mobility-related request message from a third base station before sending the mobility-related request message to a second base station, the third base station being an eNB or a donor CU or a gNB; 15. The method of claim 14, further comprising: (Item 16) The method according to item 14, wherein the mobility-related request message is a handover request message or an SgNB addition request message. (Item 17) Item 15. The method of item 14, wherein the mobility-related ACK message is a handover request acknowledgment message or an SgNB addition request acknowledgment message. (Item 18) The method of claim 15, wherein the mobility-related request message is an SgNB change request message. (Item 19) Item 15. The method of item 14, further comprising: configuring, in the donor CU, (a) a BH RLC channel, or (b) a BAP sublayer routing entry for the target path, or (c) a UL traffic mapping for the target path, or (d) a DL mapping on the target IAB donor DU. (Item 20) The mobility related request or mobility related request message may include group mobility interest, or group mobility indication, or mobile IAB node indication, or IAB node indication, or information related to group mobility authorization, or User Equipment (UE) context information for one or more UEs or IAB-MTs, or BAP addresses of IAB nodes allocated by the source donor CU, or BH RLC channel configuration for an IAB-MT configured by the source donor CU, or BH RLC channel ID, or QoS, or CP traffic type, or RLC mode for a collocated IAB-DU configured by the source donor CU. Item 15. The method of item 14, comprising: an RLC channel configuration, or configuration information of a collocated IAB-DU, or a routing configuration for the collocated IAB-DU configured by the source donor CU, or a traffic mapping configuration for the collocated IAB-DU configured by the source donor CU, or a BAP routing ID and a BAP address of an IAB node along the corresponding path configured by the source donor CU, or a path ID and a BAP address of an IAB node along the corresponding path configured by the source donor CU, or a gNB-DU UE F1AP ID, or PDCP information, or an identification of a DU serving a UE / IAB-MT including its BAP address, or its DU ID, and / or a gNB ID of a source donor CU. (Item 21) 21. The method of claim 20, wherein the configuration information of the collocated IAB-DU comprises IP address request information including an IP address request or an IPV4 address request number or an IPv6 address request number or an IPv6 prefix request, or DU ID, or DU served cell information including a PCI or CGI or PLMN ID list. (Item 22) Item 15. The method of item 14, wherein the mobility related ACK message comprises a group mobility indication, or an RRC reconfiguration message for one or more UEs or IAB-MTs, or collocated IAB-DU configuration information, or routing configuration information configured by the second base station, or traffic mapping configuration information configured by the second base station, or indication information indicating the routing configuration information or the traffic mapping configuration information applicable on a target path. (Item 23) 21. The method of claim 20, wherein the collocated IAB-DU configuration information comprises an IP address, or an IP address prefix, or an IP address use, or an allocated IP address information for the IAB-DU comprising an IAB donor DU BAP address, or an IP address of the target donor CU, or a reconfigured DU ID for the collocated IAB-DU, or updated DU served cell information including a PCI or CGI or PLMN ID list. (Item 24) receiving, at the second base station, an F1 configuration request message from an IAB node after receiving the mobility related request message from a first base station, the F1 configuration message including a gNB ID of a source IAB donor; 15. The method of claim 14, further comprising: (Item 25) Item 15. The method of item 14, wherein after receiving the mobility related request message from the first base station, in the second base station, sending an F1AP message to an IAB node, the message including multiple gNB-DU UE F1AP IDs, or UL UP TNL information, or new UL UP TNL information, or BH information, or an old TNL address of a gNB-CU, or a new TNL address of a gNB-CU, or a source F1AP UE context release indication, or a CU change indication, or an inter-donor transition indication, and the F1AP message is a UE context setup request message, or a UE context modification request message, or an IAB UP configuration update request message, or a new F1AP message. (Item 26) Item 15. The method of item 14, wherein after sending the mobility related ACK message to the first base station, the second base station sends a UE context release message to the first base station, where the UE context release message includes a plurality of pairs of source / target NG-RAN node UE XnAP IDs, or a plurality of pairs of old and new eNB UE X2AP IDs. (Item 27) Item 15. The method of item 14, wherein after receiving the mobility related ACK message from the second base station, at the first base station, sending a message to the second base station, the message including SN status information for a plurality of UEs / IAB-MTs, or a plurality of pairs of source and target NG-RAN node UE XnAP IDs, or a plurality of pairs of old and new eNB UE X2AP IDs. (Item 28) 1. A method for transmitting information, comprising: receiving PDCP information at a target network node; performing, at the target network node, (a) decryption using the received PDCP information, or (b) header recovery using the received PDC information, or (c) integrity verification using the received PDCP information; A method comprising: (Item 29) 29. The method of claim 28, wherein before receiving the PDCP information, the target network node transmits PDCP configuration request information to the source network node, the PDCP configuration request information including a PDCP key request indication or a PDCP key indication. (Item 30) 29. The method of claim 28, wherein the PDCP information includes encryption-related information, or integrity-related information, or a hyperframe number (HFN), or header compression-related information. (Item 31) Item 31. The method according to item 30, wherein the encryption-related information includes an encryption key or a cipheringAlgorithm, and the integrity-related information includes an integrity key or an integrityProtAlgorithm. (Item 32) 2. The method of claim 1, wherein the network node is a donor CU or an IAB node. (Item 33) 2. The method of claim 1, wherein the wireless device is a user equipment (UE) and the child node is an IAB node. (Item 34) 3. The method of claim 2, wherein the network node is a donor CU or an IAB node. (Item 35) A wireless communication device comprising a processor configured to implement the methods recited in any one or more of items 1-34. [Brief description of the drawings]

[0016] [Figure 1]FIG. 1 illustrates an embodiment of an IAB deployment in a moving vehicle.

[0017] [Diagram 2] FIG. 2 illustrates an embodiment of an IAB topology.

[0018] [Diagram 3] FIG. 3 illustrates an IAB topology in which handover of an IAB node is performed.

[0019] [Figure 4] FIG. 4 illustrates an embodiment in which mobility configuration is transmitted.

[0020] [Diagram 5] FIG. 5 illustrates an embodiment in which mobility assistance information is transmitted.

[0021] [Figure 6] FIG. 6 illustrates an embodiment in which a node transmits mobility assistance information.

[0022] [Figure 7] FIG. 7 illustrates mobility decisions based on measurement thresholds.

[0023] [Figure 8] FIG. 8 illustrates a handover method.

[0024] [Figure 9] FIG. 9 illustrates the handover procedure.

[0025] [Figure 10] FIG. 10 illustrates the steps of transmitting PDCP information for use in transmitting a packet.

[0026] [Figure 11] FIG. 11 illustrates an eNB connected to a transition IAB node.

[0027] [Figure 12] FIG. 12 illustrates the topology transition.

[0028] [Figure 13] FIG. 13 illustrates the topology transition.

[0029] [Figure 14] FIG. 14 illustrates an example of a wireless communication system in which techniques according to one or more embodiments of the present technology may be applied.

[0030] [Figure 15] FIG. 15 is a block diagram representation of a portion of a wireless station in accordance with one or more embodiments of the present technology may be applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The present disclosure relates to wireless systems, and more particularly, to reducing packet loss during handover in IAB deployments.

[0032] For example, an integrated access and backhaul (IAB) system supports wireless backhauling by deploying new radio (NR) cells to reduce the need for wireline transport infrastructure.

[0033] The end node of the NR backhaul network on the network side is generally referred to as an IAB donor and represents a gNB, which is a logical node with additional functionality to support IAB. An IAB node supports gNB distributed unit (gNB-DU) functionality, which enables NR access to user equipment (UE) and next-hop IAB nodes. An IAB node also supports functionality related to IAB-MT, which enables connection to another IAB node or IAB donor's gNB-DU.

[0034] In one embodiment, as shown in FIG. 1, a moving vehicle such as a high-speed train 101 has several passengers with one or more mobile terminals (MTs) or user equipment (UE) 103-106. The UEs 103-106 are wirelessly connected to an IAB node 102, which in turn is connected to a donor or parent IAB node 107 or 108. As the high-speed train moves, handovers between parent IAB nodes occur. The UEs 103-106 access the network via the IAB node 102, which in turn accesses the network via a parent IAB node. It should be understood that the use of UE and MT herein is not mutually exclusive and it should be assumed that either term may refer to either an MT or a UE. It should also be understood that a parent IAB node is to be encompassed by the term "base station." It should be understood that although mobile vehicles are discussed, the techniques disclosed herein are also applicable to static IAB nodes, which may want to perform a transition due to load balancing or due to a backhaul radio link failure (BH RLF).

[0035] The relative positions between the UEs 103-106 and the IAB nodes 102 will likely not change much as the train 101 progresses across. However, the relative positions between the IAB nodes 102 and each IAB donor will likely change frequently as the train 101 progresses.

[0036] As a result, the present disclosure provides a system and method for implementing handover of an IAB node 102, which reduces signaling overhead and improves service continuity.

[0037] FIG. 2 illustrates an IAB topology. Parent nodes 201 and 202 have IAB-DU functionality, and they provide NR access to IAB node 203. IAB node 203 functions as both an IAB MT and an IAB DU. IAB node 203 can connect to parent nodes 201 and 202 as an IAB MT and provide access to child nodes 204-206 as an IAB DU. Child nodes 204-206 have IAB MT functionality. As can be understood, any node in the topology can function as a donor or a termination, as long as it is designed with the functionality.

[0038] FIG. 3 illustrates an IAB topology in which handover of an IAB node is performed.

[0039] A UE 302 is wirelessly coupled to an IAB node 304, which is wirelessly coupled to an IAB node 306. A UE 308 is coupled to the IAB node 306. It should be appreciated that any number of UEs or MTs may be coupled to any of the IAB nodes.

[0040] As indicated by arrow 322, IAB node 306 is transitioning from IAB node 314 to IAB node 312. IAB node 314 is coupled to IAB donor DU 318, and IAB node 312 is coupled to IAB donor DU 324. Both IAB donors 318 and 316 are coupled to different IAB donor CUs. In the case of Figure 3, IAB node 306 transitions not only between IAB nodes, but also between IAB donor CUs.

[0041] It should be understood that the disclosed topology is merely exemplary: any number of nodes, UEs, or donors may be present in an IAB deployment.

[0042] The disclosed topology applies to the embodiments disclosed herein.

[0043] 4 illustrates an embodiment in which mobility configuration is transmitted. In step 402, an IAB node transmits configuration information to an IAB child node or UE. In step 404, the IAB child node or UE uses the mobility configuration information for mobility. In an embodiment, the mobility configuration information comprises (a) indication information related to whether a parent node has performed or will perform an inter-CU transition, or (b) indication information related to whether an ancestor node has performed or will perform an inter-CU transition, or (c) indication information related to initiating measurements, or (d) measurement configuration.

[0044] In an embodiment, the CU sends mobility configuration information to the IAB MT / UE, where the mobility configuration information includes at least one of the following: (a) indication information related to whether a parent node has performed or will perform an inter-CU transition, or (b) indication information related to whether an ancestor node has performed or will perform an inter-CU transition, or (c) indication information related to initiating measurements, or (d) measurement configuration.

[0045] FIG. 5 illustrates an embodiment in which mobility assistance information is transmitted. In step 502, a network node receives mobility assistance information from a wireless device or an IAB node. The network node may also be an IAB donor CU or an IAB node. In an embodiment, in step 504, the network node decides whether to perform a transition of the wireless device. In an embodiment, the mobility assistance information comprises (a) a measurement result, or (b) a group mobility indication, or (c) a group mobility interest, or (d) a group mobility intent, or (e) a group mobility interest, or (f) a group mobility intent, or (g) a mobility type, or (h) information about a target cell, or (i) information about a candidate cell. In another embodiment, the mobility assistance information is received via a radio resource control (RRC) message, or via a BAP sublayer, or via a MAC sublayer.

[0046] In an embodiment, the UE / IAB-MT sends mobility assistance information to the donor CU. The mobility assistance information includes at least one of the following: measurement result, group mobility indication / interest / intent, mobility type, group mobility interest, group mobility intent, target cell information, or candidate cell information. The UE / IAB MT can send the mobility assistance information to the donor CU via an RRC message, such as an RRCSetupRequest, RRCSetupComplete, RRCReestablishmentComplete, RRCReestablishmentRequest, RRCResumeRequest, RRCResumeComplete, UEAssistanceInformation, or measurementreport message. In an embodiment, the source donor CU decides whether to perform a mobility procedure for the corresponding UE / IAB MT.

[0047] FIG. 6 illustrates an embodiment in which an IAB node or UE transmits mobility assistance information. In step 602, the mobility assistance information is transmitted to an IAB donor CU. In step 604, the mobility assistance information is used for handover. In an embodiment, the mobility assistance information comprises (a) measurement results, or (b) group mobility indication, or (c) group mobility interest, or (d) group mobility intent, or (e) a group mobility interest, or (f) group mobility intent, or (g) mobility type, or (h) information about a target cell, or (i) information about a candidate cell. In an embodiment, the mobility type comprises group mobility, or inter-CU transition, or inter-DU transition, or intra-CU transition, or intra-DU transition.

[0048] In an embodiment, the UE / IAB node may optionally first receive mobility configuration information from an IAB donor or parent IAB node. The mobility configuration information includes at least one of the following: (a) indication information related to whether the parent node has performed or will perform an inter-CU transition, or (b) indication information related to whether the ancestor node has performed or will perform an inter-CU transition, or (c) indication information related to initiating measurements, or (d) measurement configuration. Then, the UE / IAB node decides whether to perform mobility, or the UE / IAB node decides a mobility type, e.g., group mobility, inter-CU transition, inter-DU transition, intra-CU transition, intra-DU transition, or the UE / IAB node decides a target cell, or the UE / IAB node decides a candidate cell. Then, the UE / IAB node sends mobility assistance information to the donor CU. The mobility assistance information includes at least one of the following: measurement results, group mobility indication / interest / intent, group mobility interest, group mobility intent, mobility type, target cell information, or candidate cell information.

[0049] FIG. 7 illustrates a mobility decision based on a measurement threshold. In step 702, a measurement threshold is received via a radio resource control (RRC) message transmitted from an IAB donor CU. In step 704, serving cell measurements are performed. In step 706, the network node transmits a mobility configuration to the network node if the result is lower than the threshold. In an embodiment, the measurement threshold is an RSRP threshold based on SS / PBCH blocks or based on CSI-RS. In an embodiment, the mobility configuration information comprises (a) indication information related to whether a parent network node has or will perform an inter-CU transition, or (b) indication information related to whether an ancestor node has or will perform an inter-CU transition, or (c) indication information related to initiating a measurement, or (d) a measurement configuration. In another embodiment, the mobility configuration is transmitted (a) via the BAP sublayer or (b) via the MAC CE. In an embodiment, the mobility assistance information comprises (a) measurement results, or (b) group mobility indication, or (c) group mobility interest, or (d) group mobility intent, or (e) group mobility interest, or (f) group mobility intent, or (g) mobility type, or (h) information regarding the target cell, or (i) information regarding the candidate cell.

[0050] In an embodiment, the donor CU transmits a measurement threshold to the IAB node via RRC. For example, the measurement threshold can be an RSRP threshold based on SS / PBCH blocks or based on CSI-RS. The IAB node performs measurements of the serving cell, and when the measured RSRP is lower than the measurement threshold, the IAB node transmits mobility configuration information to the child IAB node / UE. Optionally, when the IAB node receives mobility configuration information from a parent node, it can transmit mobility configuration information to its child node. In an embodiment, the mobility configuration information includes at least one of the following: (a) indication information related to whether the parent node has performed or will perform an inter-CU transition, or (b) indication information related to whether the ancestor node has performed or will perform an inter-CU transition, or (c) indication information related to initiating a measurement, or (d) measurement configuration. In an embodiment, the IAB node can transmit the mobility configuration information to the child IAB node / UE using one of the following methods: (1) the IAB node transmits the mobility configuration information to the child IAB node via the BAP sublayer, e.g., via a BAP control PDU; or (2) the IAB node transmits the mobility configuration information to the child IAB node / UE via a MAC CE. In an embodiment, the IAB node can transmit the mobility assistance information to the donor CU, which then transmits the mobility configuration information to the child IAB node / UE via RRC. In an embodiment, the mobility assistance information includes at least one of the following: measurement results or group mobility indication / interest / intent or group mobility interest or group mobility intent or mobility type or target cell information or candidate cell information. In an embodiment, the child IAB MT or UE performs measurements on serving cells and / or non-serving cells. Optionally, the child IAB MT or UE transmits the mobility assistance information to the donor CU.

[0051] FIG. 8 illustrates a handover method. In step 802, the base station transmits a mobility related request message to a second base station, the base station being an eNB or a donor CU or a gNB. In step 804, the base station receives a mobility related ACK message from the second base station. Optionally, prior to step 802, the base station may receive a mobility related request message from a third base station, the base station being an eNB or a donor CU or a gNB. In an embodiment, the mobility related request message is a handover request message or an SgNB addition request message. In an embodiment, the mobility related ACK message is a handover request acknowledgement message or an SgNB addition request acknowledgement message. In another embodiment, the mobility related request message is an SgNB change request message.

[0052] In an embodiment, the mobility related request or mobility related request message includes a group mobility interest, or a group mobility indication, or a mobile IAB node indication, or an IAB node indication, or information related to group mobility authorization, or user equipment (UE) context information for one or more UEs or IAB-MTs, or a BAP address of an IAB node allocated by the source donor CU, or a BH RLC channel configuration for an IAB-MT configured by the source donor CU, or a BH RLC channel ID or a QoS or a CP traffic type or an RLC mode for a collocated IAB-DU configured by the source donor CU. The configuration information of the collocated IAB-DU comprises an RLC channel configuration, or a routing configuration for the collocated IAB-DU configured by the source donor CU, or a traffic mapping configuration for the collocated IAB-DU configured by the source donor CU, or a BAP routing ID and BAP address of an IAB node along the corresponding path configured by the source donor CU, or a path ID and BAP address of an IAB node along the corresponding path configured by the source donor CU, or an identification of a DU serving the UE / IAB-MT, including a gNB-DU UE F1AP ID, or PDCP information, or its BAP address, or its DU ID, and / or a gNB ID of the source donor CU. In an embodiment, the configuration information of the collocated IAB-DU comprises an IP address request information including an IP address request, or an IPV4 address request number, or an IPv6 address request number, or an IPv6 prefix request, or an updated DU served cell information including a DU ID, or a PCI or CGI or PLMN ID list.In an embodiment, the mobility related ACK message comprises indication information indicating a group mobility indication, or an RRC reconfiguration message for one or more UEs or IAB-MTs, or collocated IAB-DU configuration information, or routing configuration information configured by the second base station, or traffic mapping configuration information configured by the second base station, or routing configuration information or traffic mapping configuration information applicable on the target path.

[0053] In yet another embodiment, the collocated IAB-DU configuration information comprises an IP address, or an IP address prefix, or an IP address use, or an allocated IP address information for the IAB-DU comprising an IAB donor DU BAP address, or an IP address of a target donor CU, or a reconfigured DU ID for the collocated IAB-DU, or an updated DU served cell information including a PCI or CGI or PLMN ID list.

[0054] In step 806, the donor CU configures (a) a BH RLC channel, (b) a BAP sub-layer routing entry on the target path between the target parent IAB node and the target IAB donor DU, (c) UL traffic mapping for the target path, or (d) DL mapping on the target IAB donor DU.

[0055] In step 808, after receiving the mobility related message from the second base station, an F1 configuration request message is received from the IAB node, where the F1 configuration message includes a gNB ID of the source IAB donor CU. In yet another embodiment, after receiving the mobility related message from the first base station, the second base station sends an F1AP message to the IAB node, the message including a plurality of gNB-DU UE F1AP IDs, or UL UP TNL information, or new UL UP TNL information, or BH information, or old TNL address of the gNB-CU, or new TNL address of the gNB-CU, or source F1AP UE context release indication, or CU change indication, or inter-donor transition indication, and the F1AP message is a UE context setup request message, or a UE context modification request message, or an IAB UP configuration update request message, or a new F1AP message. In yet another embodiment, the step of sending a UE context release message after sending the mobility related ACK message to the first base station is sent to the first base station, the UE context release message including a plurality of pairs of source / target NG-RAN node UE XnAP IDs, or a plurality of pairs of old and new eNB UE X2AP IDs. In yet another embodiment, after receiving a mobility related ACK message from the second base station, the first base station sends a message to the second base station, the message including SN status information for the plurality of UEs / IAB-MTs, or a plurality of pairs of source and / or target NG-RAN node UE XnAP IDs, or a plurality of pairs of old and new eNB UE X2AP IDs. In yet another embodiment, after receiving a mobility related ACK message from the second base station, the first base station sends a message to a third base station, the message including SgNB change confirmation for the plurality of UEs / IAB-MTs, or a plurality of pairs of MeNB UE X2AP IDs and SgNB UE X2AP IDs. In yet another embodiment, after receiving a mobility related ACK message from the second base station, the first base station sends a mobility release message to the third base station, the mobility release message including SgNB release request information for the plurality of UEs / IAB-MTs, or a plurality of pairs of MeNB UE X2AP IDs and SgNB UE X2AP IDs.In yet another embodiment, after receiving a mobility release message from the first base station, at the third base station, sending a message to the first base station, the message including SgNB release request acknowledgement information for multiple UEs / IAB-MTs or multiple pairs of MeNB UE X2AP IDs and SgNB UE X2AP IDs. The SgNB addition request ACK message is sent from the target donor CU to the eNB.

[0056] It should be understood that the steps described herein are merely exemplary and that any one method step is not required or may be omitted. Further, it should be understood that each step is not required for a full mobility procedure unless expressly described otherwise as necessary.

[0057] 9 illustrates the handover procedure. Steps 1a-1b are optional, and the transition IAB node performs measurements and sends measurement reports to the source donor CU. In an embodiment, the measurement reports are included in a ULRRC message forwarding and sent from the source parent node to the source donor CU.

[0058] Step 2 is optional. Here, the source donor CU performs the mobility decision. The mobility decision described herein may be applied.

[0059] In step 3, the source donor CU sends a handover request message to the target donor CU. In an embodiment, the handover request message includes the following: (a) group mobility interest, or group mobility indication, or mobile IAB node indication, or IAB node indication, or group mobility authorization information, or (b) UE context information for multiple UEs or IAB-MT, or (c) BAP addresses of IAB nodes allocated by the source donor CU, or (d) BH RLC channel configuration for IAB-MT configured by the source donor CU, or (e) configuration information of the collocated IAB-DU including one of the following: (i) BH RLC channel ID, QoS, CP traffic type, RLC mode, etc., or (ii) IP address request information including one of the following IP address request: IPv4 address request number, IPv6 address request number, or IPv6 address prefix request, etc., or (iii) DU ID, or (iv) PCI, CGI, PLMN The source donor CU may include at least one of the following: (a) a BH RLC channel configuration for the collocated IAB-DU configured by the source donor CU, including one of the updated DU served cell information including an ID list, etc.; (b) a BH RLC channel configuration for the collocated IAB-DU configured by the source donor CU; or (c) a traffic mapping configuration for the collocated IAB-DU configured by the source donor CU; or (d) a BAP routing ID and BAP address of an IAB node along the corresponding route configured by the source donor CU; or (e) a route ID and BAP address of an IAB node along the corresponding route configured by the source donor CU; or (f) a gNB-DU UE F1AP ID; or (i) an identification of a DU serving the UE / IAB-MT, e.g., a BAP address, and / or a DU ID and / or gNB ID of the source donor CU.

[0060] In step 4, the target donor CU initiates a UE context setup procedure with the target parent node. After the target parent node receives the UE context setup request message, it sends a UE context setup response.

[0061] In step 5, the target donor CU sends a HANDOVER REQUEST ACK message to the source donor CU. The HANDOVER REQUEST ACKNOWLEDGE message includes at least one of the following: (1) a group mobility indication, or (2) a HandoverCommand message for multiple UEs or IAB-MTs, or (3) a collocated IAB-DU configuration information including one of the following: (a) allocated IP address information for the IAB-DU, including one of the following: IP address, IP address prefix, IP address usage, IAB donor DU BAP address, or (b) an IP address of the target donor CU, or (c) a reconfigured DU ID for the collocated IAB-DU, or (d) updated DU served cell information including PCI, CGI, PLMN ID list, etc.

[0062] In steps 6 and 7, the source donor CU sends a handover command message to the descendant IAB nodes of the transition IAB and the UE and the transition IAB node. The handover command message is included in a DL RRC message transfer message and sent from the source donor CU to the IAB-DU.

[0063] In step 8, the source donor CU sends an SN Status Transfer message to the target donor CU. The SN Status Transfer message may include SN status information for multiple UEs / IAB-MTs. The SN Status Transfer message may include one or more pairs of source / target NG-RAN node UE XnAP IDs, or multiple pairs of old and new eNB UE X2AP IDs.

[0064] In step 9, the transitioning IAB node performs a random access with the target parent node.

[0065] In steps 10-11, after receiving the RRCreconfiguration, the UE / IAB node sends an RRCReconfigurationcomplete message to the target donor CU. The RRCReconfigurationcomplete message is included in a UL RRC message transfer message and sent from the access IAB node to the target donor CU.

[0066] In step 12, the target donor CU configures at least one of a BH RLC channel or a BAP sub-layer routing entry on the target path between the target parent IAB node and the target IAB donor DU or a UL traffic mapping for the target path or a DL mapping on the target IAB donor DU. These configurations may be performed at an early stage, for example, immediately after step 5.

[0067] In step 13, the transition IAB node initiates an F1 setup procedure with the target donor CU using the IP address received via RRC. The transition IAB node sends an F1 setup request message to the target donor CU. Optionally, the F1 setup request message includes the gNB ID of the source IAB donor.

[0068] In step 14a, the target donor CU sends a UE context setup request message to the transition IAB node. The UE context setup request message includes one or more gNB-DU UE F1AP IDs. And the transition IAB node then sends an F1AP UE context setup response message to the target donor CU. Optionally, the UE context setup request message includes indication information. The indication information includes at least one of the following: (a) source F1AP UE context release indication, or (b) CU change indication, or (c) inter-donor transition indication. In an embodiment, the transition IAB node may release the corresponding UE context associated with the source donor CU after receiving the indication information.

[0069] Step 14b may be performed instead of step 14a. In step 14b, the target donor CU sends a UE context modification request message to the transition IAB node. In an embodiment, the UE context modification request message includes one or more gNB-DU UE F1AP IDs. The transition IAB node then sends an F1AP UE context modification response message to the target donor CU. In an embodiment, the UE context modification request message includes indication information. The indication information includes at least one of the following: (a) source F1AP UE context release indication, or (b) CU change indication, or (c) inter-donor transition indication.

[0070] In step 15, the target donor CU sends a UE context release message to the source donor CU. The UE context release message includes one or more pairs of source / target NG-RAN node UE XnAP IDs, or multiple pairs of old and new eNB UE X2AP IDs. Step 15 is optional.

[0071] In step 16, an F1 setup procedure is performed for descendant nodes of the transition IAB node, and a UE context setup or modification procedure is performed for descendant nodes of the transition IAB node.

[0072] In step 17, the UE context of the UE / transition IAB node / child IAB node in the source donor CU is released, and the routing / traffic mapping / BH RLC channel configuration is released or reconfigured in the source path.

[0073] 10 illustrates steps of transmitting PDCP information for use in transmitting packets. In step 1002, optionally before receiving the PDCP information, PDCP configuration request information is transmitted to the source network node, the PDCP configuration request information including a PDCP key request indication or a PDCP key indication. In step 1004, the network node receives the PDCP information. In step 1006, the network node uses the PDCP information to decrypt, perform header decompression, or perform integrity verification. In an embodiment, the PDCP information includes encryption-related information, or integrity-related information, or a hyperframe number (HFN), or header compression-related information.

[0074] In yet another embodiment, the target donor CU sends the routing / traffic mapping configuration of the target path to the IAB node during the handover preparation phase, and the routing / traffic mapping configuration information of the target path is contained in the HO CMD message, which includes the routing configuration / F1-U traffic mapping information. In an embodiment, the routing / traffic mapping configuration information of the target path is contained in the HO request ACKNOWLEDGE message, and the source donor CU sends the routing / traffic mapping configuration to the IAB node via the F1AP message. In yet another embodiment, an indication is included with the updated routing / traffic mapping configuration that it is applied on the target path.

[0075] 11 illustrates an eNB connected to a transition IAB node. An eNB 1112 is connected to a transition IAB node 1114, which is itself connected to a UE 1116 and a child IAB node 1118. The transition IAB node 1114 transitions from (a) an IAB node 1108 connected to an IAB donor DU 1106, which is connected to an IAB donor CU 1104, to (b) an IAB node 1102 connected to an IAB donor DU 1120, which is connected to an IAB donor CU 1124. The transition is illustrated with arrow 1126.

[0076] FIG. 12 illustrates a topology transition, such as the one illustrated in FIG.

[0077] Step 0 is optional. In step 0, the transition IAB node sends a measurement report to the eNB or the source donor CU.

[0078] In step 1, the source donor CU initiates the SN change procedure by sending an SgNB Change Request message to the eNB. In an embodiment, the SgNB change request message may include the following: (a) group mobility interest, or group mobility indication, or mobile IAB node indication, or IAB node indication, or group mobility authorization information; or (b) UE context information for multiple UEs or IAB-MT; or (c) BAP addresses of IAB nodes allocated by the source donor CU; or (d) BH RLC channel configuration for the IAB-MT configured by the source donor CU; or (e) BH RLC channel configuration for the collocated IAB-DU configured by the source donor CU, including one of the following: BH RLC channel ID, QoS, CP traffic type, RLC mode, etc.; or (f) IP address request information including one of the following: (i) IP address request, i.e., IPv4 address request number, IPv6 address request number, IPv6 address prefix request, etc.; or (ii) DU ID; or (iii) PCI, CGI, PLMN or (g) configuration information of the collocated IAB-DU, including one of the updated DU served cell information including an ID list, etc., or (g) routing configuration for the collocated IAB-DU configured by the source donor CU, or (h) traffic mapping configuration for the collocated IAB-DU configured by the source donor CU, or (i) BAP routing IDs and BAP addresses of IAB nodes along the corresponding route configured by the source donor CU, or (j) path IDs and BAP addresses of IAB nodes along the corresponding route configured by the source donor CU, or (k) gNB-DU UE F1AP ID, or (l) at least one of the identifications of the DU serving the UE / IAB-MT, e.g., BAP address, DU ID and / or gNB ID of the source donor CU.

[0079] In step 2, the eNB sends an SgNB addition request message to the target donor CU.

[0080] In step 3, the target donor CU initiates a UE context setup procedure with the target parent node. After the target parent node receives the UE context setup request message, it sends a UE context setup response.

[0081] In step 4, the target donor CU sends an SgNB Addition Request ACK message to the eNB. The SgNB Addition Request ACK message includes at least one of the following: (a) a group mobility indication, or (b) an RRC reconfiguration message for multiple UEs or IAB-MTs, or (c) collocated IAB-DU configuration information including one of the following: (i) allocated IP address information for the IAB-DU, including one of the following: IP address, IP address prefix, IP address usage, IAB donor DU BAP address, (ii) an IP address of the target donor CU, (iii) a reconfigured DU ID for the collocated IAB-DU, or (iv) updated DU served cell information, including PCI, CGI, PLMN ID list, etc.

[0082] In steps 5-8, the eNB sends an RRC Connection Reconfiguration message containing the new configuration to the child / transition IAB node and the UE. The IAB node or UE applies the new configuration and sends an RRCConnectionReconfigurationComplete message to the eNB.

[0083] In step 9, the eNB sends an SgNB Change Confirm message to the source donor CU.

[0084] In step 10, if the RRC connection reconfiguration procedure is successful, the eNB informs the target donor CU via an SgNB reconfiguration complete message.

[0085] In step 11, the transition IAB node performs a random access procedure with the target parent node or the target donor CU.

[0086] In step 12, the target donor CU configures at least one of a BH RLC channel or a BAP sub-layer routing entry on the target path between the target parent IAB node and the target IAB donor DU or a UL traffic mapping for the target path or a DL mapping on the target IAB donor DU. These configurations may be performed at an early stage, for example, immediately after step 4.

[0087] In step 13, the transition IAB node initiates an F1 setup procedure with the target donor CU using the IP address received via RRC. The transition IAB node sends an F1 setup request message to the target donor CU. Optionally, the F1 setup request message includes the gNB ID of the source IAB donor.

[0088] In step 14a, the target donor CU sends a UE context setup request message to the transition IAB node. In an embodiment, the UE context setup request message includes one or more gNB-DU UE F1AP IDs. And the transition IAB node then sends an F1A PUE context setup response message to the target donor CU. Optionally, the UE context setup request message includes indication information. The indication information includes at least one of the following: (a) source F1AP UE context release indication, or (b) CU change indication, or (c) inter-donor transition indication. In an embodiment, the transition IAB node releases the corresponding UE context associated with the source donor CU after receiving the indication information.

[0089] Step 14b can be performed instead of step 14a. In step 14b, the target donor CU sends a UE context modification request message to the transition IAB node. The UE context modification request message includes one or more gNB-DU UE F1AP IDs. And the transition IAB node then sends an F1AP UE context modification response message to the target donor CU. Optionally, the UE context modification request message includes indication information. The indication information includes at least one of the following: (a) source F1AP UE context release indication, or (b) CU change indication, or (c) 6) inter-donor transition indication.

[0090] In step 15, an F1 setup procedure is performed for the descendant nodes of the transition IAB node, and a UE context setup or modification procedure is performed for the descendant nodes of the transition IAB node.

[0091] In step 16, the UE context of the UE / transition IAB node / child IAB node in the source donor CU is released, and the routing / traffic mapping / BH RLC channel configuration is released or reconfigured in the source path.

[0092] FIG. 13 illustrates a topology transition, such as the one illustrated in FIG.

[0093] Step 0 is optional. In step 0, the transition IAB node sends a measurement report to the eNB.

[0094] In step 1, the eNB initiates the SN change procedure by sending an SgNB Addition Request message to the target donor CU. The SgNB Addition Request message may contain the following: (a) group mobility interest, or group mobility indication, or mobile IAB node indication, or IAB node indication, or group mobility authorization information, or (b) UE context information for multiple UEs or IAB-MT, or (c) BAP addresses of IAB nodes allocated by the source donor CU, or (d) BH RLC channel configuration for the IAB-MT configured by the source donor CU, or (e) the following: (i) BH RLC channel configuration for the collocated IAB-DU configured by the source donor CU, including one of the following: BH RLC channel ID, QoS, CP traffic type, RLC mode, etc., or (f) the following: (i) IP address request information including one of the following IP address requests: IPv4 address request number, IPv6 address request number, or IPv6 address prefix request, etc., or (ii) DU ID, or (iii) PCI, CGI, PLMN or (g) configuration information of the collocated IAB-DU including one of the updated DU served cell information including ID list, etc., or (g) routing configuration for the collocated IAB-DU configured by the source donor CU, or (h) traffic mapping configuration for the collocated IAB-DU configured by the source donor CU, or (i) BAP routing IDs and BAP addresses of IAB nodes along the corresponding route configured by the source donor CU, or (j) path IDs and BAP addresses of IAB nodes along the corresponding route configured by the source donor CU, or (k) gNB-DU UE F1AP ID, or at least one of the identification of the DU serving the UE / IAB-MT, e.g., BAP address, DU ID and / or gNB ID of the source donor CU.

[0095] In step 2, the target donor CU sends an SgNB Addition Request ACK message to the eNB. The SgNB Addition Request ACK message includes at least one of the following: (a) a group mobility indication, or (b) an RRC reconfiguration message for multiple UEs or IAB-MTs, or (c) a collocated IAB-DU configuration information including one of the following: (i) allocated IP address information for the IAB-DU, including one of the following: IP address, IP address prefix, IP address usage, IAB donor DU BAP address, or (ii) an IP address of the target donor CU, or (iii) a reconfigured DU ID for the collocated IAB-DU, or (iv) updated DU served cell information, including PCI, CGI, PLMN ID list, etc.

[0096] Step 3 is optional. In step 3, the eNB sends an SgNB Release Request message to the source donor CU.

[0097] Step 4 is optional. In step 4, the source donor CU sends an SgNB Release Request ACK message to the eNB.

[0098] In steps 5-8, the eNB sends an RRC Connection Reconfiguration message containing the new configuration to the child / transition IAB node and the UE. The IAB node or UE applies the new configuration and sends an RRCConnectionReconfigurationComplete message to the eNB.

[0099] In step 9, if the RRC connection reconfiguration procedure is successful, the eNB informs the target donor CU via an SgNB reconfiguration complete message.

[0100] In step 10, the transition IAB node performs a random access procedure with the target parent node or the target donor CU.

[0101] In step 11, the target donor CU configures at least one of a BH RLC channel or a BAP sub-layer routing entry on the target path between the target parent IAB node and the target IAB donor DU or a UL traffic mapping for the target path or a DL mapping on the target IAB donor DU. These configurations may be performed at an early stage, for example, immediately after step 4.

[0102] In step 12, the transition IAB node initiates an F1 setup procedure with the target donor CU using the IP address received via RRC. The transition IAB node sends an F1 setup request message to the target donor CU. Optionally, the F1 setup request message includes the gNB ID of the source IAB donor.

[0103] In step 13a, the target donor CU sends a UE context setup request message to the transition IAB node. The UE context setup request message includes one or more gNB-DU UE F1AP IDs. And the transition IAB node then sends an F1AP UE context setup response message to the target donor CU. Optionally, the UE context setup request message includes indication information. The indication information includes at least one of the following: (a) source F1AP UE context release indication, or (b) CU change indication, or (c) inter-donor transition indication. In an embodiment, the transition IAB node may release the corresponding UE context associated with the source donor CU after receiving the indication information.

[0104] Step 13b can be performed instead of step 13a. In step 13, the target donor CU sends a UE context modification request message to the transition IAB node. The UE context modification request message includes one or more gNB-DU UE F1AP IDs. And the transition IAB node then sends an F1AP UE context modification response message to the target donor CU. Optionally, the UE context modification request message includes indication information. The indication information includes at least one of the following: (a) source F1AP UE context release indication, or (b) CU change indication, or (c) inter-donor transition indication.

[0105] In step 14, an F1 setup procedure is performed for descendant nodes of the transition IAB node, and a UE context setup or modification procedure is performed for descendant nodes of the transition IAB node.

[0106] In step 15, the UE context of the UE / transition IAB node / child IAB node in the source donor CU is released, and the routing / traffic mapping / BH RLC channel configuration is released or reconfigured in the source path.

[0107] It should be understood that the steps disclosed herein are illustrative and are not necessarily intended to be performed in the exact order listed. Moreover, it is not intended that each step is required. Steps may be optionally excluded or substituted with alternative mechanisms.

[0108] Although some embodiments describe transmission of certain data to a node in an IAB deployment, it should be understood that the present disclosure contemplates receiving and further transmission. For example, if an IAB node is described as transmitting a portion of data intended for a UE, it should be understood that any number of child IAB nodes exist between the IAB node transmitting the data and the UE. It should be understood that those IAB nodes transmit data as well. The same applies to any node between the path of the IAB node transmitting the data and the IAB donor CU.

[0109] FIG. 14 illustrates an example of a wireless communication system 1400 to which a technique according to one or more embodiments of the present technology may be applied. The wireless communication system 1400 may include one or more base stations (BSs) 1405a, 1405b, one or more wireless devices 1410a, 1410b, 1410c, 1410d, and a core network 1425. The base stations 1405a, 1405b may provide wireless services to the wireless devices 1410a, 1410b, 1410c, and 1410d in one or more wireless sectors. In some implementations, the base stations 1405a, 1405b include directional antennas for producing two or more directional beams to provide wireless coverage in different sectors. With reference to FIG. 1-3, it should be understood that the base stations may be a series of IAB nodes.

[0110] The core network 1425 can communicate with one or more base stations 1405a, 1405b. The core network 1425 provides connectivity with other wireless communication systems and with wired communication systems. The core network may include one or more service subscription databases to store information associated with subscribed wireless devices 1410a, 1410b, 1410c, and 1410d. The first base station 1405a can provide wireless services based on a first wireless access technology, while the second base station 1405b can provide wireless services based on a second wireless access technology. The base stations 1405a and 1405b may be co-located or separately located in a region according to a deployment scenario. The wireless devices 1410a, 1410b, 1410c, and 1410d can support multiple different wireless access technologies. The techniques and embodiments described herein may be implemented by a base station of a wireless device described herein.

[0111] FIG. 15 is a block diagram representation of a portion of a wireless station according to one or more embodiments of the present technology may be applied. A wireless station 1505, such as a base station or wireless device (or UE) or MT, may include processor electronics 1510, such as a microprocessor, that implements one or more of the wireless techniques presented herein. The wireless station 1505 may include transceiver electronics 1515 for transmitting and / or receiving wireless signals via one or more communication interfaces, such as an antenna 1520. The wireless station 1505 may include other communication interfaces for transmitting and receiving data. The wireless station 1505 may include one or more memories (not explicitly shown) configured to store information, such as data and / or instructions. In some implementations, the processor electronics 1510 may include at least a portion of the transceiver electronics 1515. In some embodiments, at least some of the disclosed techniques, modules, or functions are implemented using the wireless station 1505. In some embodiments, the wireless station 1505 may be configured to perform the methods described herein.

[0112] It should be understood that this document discloses techniques that may be embodied in various embodiments of IAB deployment. The disclosed embodiments, modules, and functional operations described herein can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed herein and their structural equivalents, or in a combination of one or more of them. The disclosed embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer-readable medium for execution by or to control the operation of a data processing apparatus. The computer-readable medium may be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition that produces a machine-readable propagated signal, or one or more combinations thereof. The term "data processing apparatus" encompasses all apparatuses, devices, and machines for processing data, including, by way of example, a programmable processor, a computer, or multiple processors or computers. In addition to hardware, the apparatus may include code that creates an execution environment for the computer program, such as code constituting a processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of these. The propagated signal is an artificially generated signal, such as a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to a suitable receiver device.

[0113] A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored within a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), within a single file dedicated to the program, or within multiple collaborative files (e.g., files that store one or more modules, subprograms, or portions of code). A computer program can be deployed to run on one computer, or on multiple computers located at one site or distributed across multiple sites and interconnected by a communication network.

[0114] The processes and logic flows described herein may be implemented by one or more programmable processors running on one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be implemented by, and apparatus may also be implemented as, special purpose logic circuitry, such as an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

[0115] Processors suitable for executing computer programs include, by way of example, both general-purpose and special-purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, the processor will receive instructions and data from a read-only memory or a random-access memory, or both. The essential elements of a computer are a processor for carrying out instructions, and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from, or transfer data to, one or more mass storage devices, such as magnetic, magneto-optical, or optical disks, for storing data. However, a computer does not require such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, by way of example, semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices, magnetic disks, such as internal hard disks or removable disks, magneto-optical disks, and CD ROM and DVD-ROM disks. The processor and memory can be supplemented by, or incorporated in, special-purpose logic circuitry.

[0116] Although this patent document contains many details, these should not be interpreted as limitations on the scope of any invention or what may be claimed, but rather as descriptions of features that may be specific to certain embodiments of a particular invention. Certain features described in this patent document in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features may be described above as acting in a combination and may even be initially claimed as such, one or more features from a claimed combination may in some cases be deleted from the combination, and the claimed combination may be directed to a subcombination or a variation of the subcombination.

[0117] Similarly, although operations are depicted in the figures in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown, or in sequential order, or that all of the illustrated operations be performed, to achieve desirable results. Further, the separation of various system components in the embodiments described in this patent document should not be understood as requiring such separation in all embodiments.

[0118] Only some implementations and examples have been described; other implementations, enhancements, and variations can be made based on what is described and illustrated in this patent document.

Claims

1. 1. A method for transmitting information, comprising: A source donor central unit (CU) sends a handover request message to a target donor CU; The source donor CU receives a handover request acknowledgement (ACK) message from the target donor CU; The source donor CU sends a handover command message to a transition integration and access backhaul (IAB) node, the transition IAB node transitioning from the source donor CU to the target donor CU; The source donor CU sends a status transfer message to the target donor CU, the status transfer message including a pair of identifiers of a user equipment, a first identifier of the user equipment being associated with a source base station and a second identifier of the user equipment being associated with a target base station; and An information transmission method comprising:

2. The method of claim 1 , further comprising: receiving a measurement report from a source parent node before sending the handover request message to the target donor CU.

3. An apparatus for wireless communication, said apparatus comprising a processor, said processor being configured to perform the method according to any of claims 1-2.

4. A non-transitory computer readable medium having stored thereon code, the code causing the processor to perform the method according to any one of claims 1 to 2 when executed by the processor.

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