Techniques for associating integrated access and backhaul (IAB) nodes with different upstream nodes

Abstract

Aspects described herein relate to operations of receiving, by a mobile termination (MT) function of an integrated access and backhaul (IAB) node, a first indication to migrate from a first IAB donor node associated with a first cell group and a first central unit (CU) to a second IAB donor node associated with a second cell group and a second CU; performing, by the IAB node and based at least in part on receiving the first indication, a first random access procedure to connect to the second cell group associated with the second IAB donor node; establishing, by the IAB node based on performing the first random access procedure, a second distributed unit (DU) function serving a fourth cell group in addition to a first DU function of the IAB node serving a third cell group.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to the following applications: Provisional Patent Application No. 63 / 045,793, filed on June 29, 2020, entitled “TECHNIQUES FOR ASSOCIATING INTEGRATED ACCESS AND BACKHAUL (IAB) NODES WITH DIFFERENT UPSTREAM NODES”; and U.S. Patent Application No. 17 / 357,631, filed on June 24, 2021, entitled “TECHNIQUES FOR ASSOCIATING INTEGRATED ACCESS AND BACKHAUL (IAB) NODES WITH DIFFERENT UPSTREAM NODES”, which are assigned to the assignee of this application and are hereby expressly incorporated herein by reference for all purposes. Technical Field

[0003]

[0004] Aspects of the present disclosure generally relate to wireless communication systems, and more particularly, to integrated access and backhaul (IAB) nodes. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as telephony, video, packet data, messaging, broadcast, and the like. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and single-carrier frequency division multiple access (SC-FDMA) systems.

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a city, country, region, and even global level. For example, the fifth generation (5G) wireless communication technology, which may be referred to as 5G New Radio (5G NR), is envisioned to extend and support different usage scenarios and applications with respect to current mobile network generations. In one aspect, 5G communication technologies may include: enhanced mobile broadband that addresses human-centric use cases for accessing multimedia content, services, and data; ultra-reliable low-latency communications (URLLC) with certain specifications for latency and reliability; and massive machine-type communications, which may allow for very large numbers of connected devices and the transmission of relatively small amounts of non-latency-sensitive information.

[0006] An integrated access and backhaul (IAB) node provides access to one or more upstream nodes (e.g., an IAB node or an IAB donor node with a wired connection or other direct connection to a core network) for one or more downstream nodes (e.g., user equipment (UE) or other IAB nodes). An IAB node can include mobile termination (MT) functionality to facilitate communications with one or more upstream nodes and distributed unit (DU) functionality to facilitate communications with one or more downstream nodes. 5G NR technologies, such as millimeter wave (mmWave), can be used to support access networks between IAB nodes and UEs and backhaul networks between IAB nodes in an IAB network. SUMMARY

[0007] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0008] According to an aspect, an apparatus for wireless communication is provided that includes a transceiver, a memory configured to store instructions, and one or more processors communicatively coupled with the memory and the transceiver. The one or more processors are configured to execute the instructions to cause the apparatus to receive, by a mobile termination (MT) functionality of an integrated access and backhaul (IAB) node, a first indication to migrate from a first IAB donor node associated with a first group of cells and a first central unit (CU) to a second IAB donor node associated with a second group of cells and a second CU, perform, by the IAB node, a first random access procedure based at least in part on receiving the first indication to connect to the second group of cells associated with the second IAB donor node, establish, by the IAB node and based on performing the first random access procedure, a second distributed unit (DU) functionality to serve a fourth group of cells in addition to a first DU functionality of the IAB node to serve a third group of cells, and trigger, based on establishing the second DU functionality, a second random access procedure for a child node to migrate from the third group of cells associated with the first DU functionality to the fourth group of cells associated with the second DU functionality.

[0009] According to another aspect, a method of wireless communication is provided. The method includes receiving, by a MT function of an IAB node, a first indication to migrate from a first IAB donor node associated with a first group of cells and a first CU to a second IAB donor node associated with a second group of cells and a second CU, performing, by the IAB node, a first random access procedure based at least in part on receiving the first indication to connect to the second group of cells associated with the second IAB donor node, establishing, by the IAB node and based on performing the first random access procedure, a second DU function serving a fourth group of cells in addition to a first DU function of the IAB node serving a third group of cells, and triggering, based on establishing the second DU function, a second random access procedure for a child node to migrate from the third group of cells associated with the first DU function to the fourth group of cells associated with the second DU function.

[0010] According to another aspect, an apparatus for wireless communication is provided. The apparatus includes means for receiving, by a MT function of an IAB node, a first indication to migrate from a first IAB donor node associated with a first group of cells and a first CU to a second IAB donor node associated with a second group of cells and a second CU, means for performing, by the IAB node, a first random access procedure based at least in part on receiving the first indication to connect to the second group of cells associated with the second IAB donor node, means for establishing, by the IAB node and based on performing the first random access procedure, a second DU function serving a fourth group of cells in addition to a first DU function of the IAB node serving a third group of cells, and means for triggering, based on establishing the second DU function, a second random access procedure for a child node to migrate from the third group of cells associated with the first DU function to the fourth group of cells associated with the second DU function.

[0011] According to yet another example, a computer-readable medium is provided that includes code executable by one or more processors for wireless communication. The code includes code to receive, by a MT function of an IAB node, a first indication to migrate from a first IAB donor node associated with a first group of cells and a first CU to a second IAB donor node associated with a second group of cells and a second CU, code to perform, by the IAB node, a first random access procedure based at least in part on receiving the first indication to connect to the second group of cells associated with the second IAB donor node, code to establish, by the IAB node and based on performing the first random access procedure, a second DU function to serve a fourth group of cells in addition to a first DU function of the IAB node to serve a third group of cells, and code to trigger, based on establishing the second DU function, a second random access procedure for a child node to migrate from the third group of cells associated with the first DU function to the fourth group of cells associated with the second DU function.

[0012] To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects can be employed, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF DRAWINGS

[0013] The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements, and in which:

[0014] Figure 1 An example of a wireless communication system is shown in accordance with various aspects of the present disclosure;

[0015] Figure 2 An example of a wireless communication system is shown in accordance with various aspects of the present disclosure;

[0016] Figure 3 is a block diagram illustrating an example of an IAB node in accordance with various aspects of the present disclosure;

[0017] Figure 4 is a flow diagram illustrating an example of a method for associating with different IAB donor nodes in accordance with various aspects of the present disclosure; and

[0018] Figure 5FIG. 1 is a block diagram illustrating an example of a MIMO communication system including a base station and a UE, in accordance with various aspects of the present disclosure. DETAILED DESCRIPTION

[0019] Various aspects are now described with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding. It can be evident, however, that aspects can be practiced without these specific details.

[0020] The described features generally relate to associating an integrated access and backhaul (IAB) node with different upstream IAB nodes (e.g., different IAB donor nodes). In an example, an IAB network can include one or more IAB donor nodes that have a direct connection with a core network, which can include a wired connection. In certain radio access technologies (RATs), such as fifth generation (5G) new radio (NR), an IAB donor node can terminate an Ng interface with the core network. In this example, an IAB donor node can include a central unit (CU) function that configures the IAB network, as well as a distributed unit (DU) function that schedules child nodes (e.g., downstream nodes) of the IAB donor node. In this example, an IAB node can include a mobile termination (MT) function as a scheduled node, which is similar to a UE scheduled by its parent IAB node or IAB donor node, and a DU function as a scheduling node that schedules child nodes of the IAB node.

[0021] The IAB network can also include one or more UEs connected to one or more of the IAB nodes. The IAB network can include an access network between the IAB nodes and UEs and a backhaul network between the IAB nodes, one or more of which can be based on 5G NR technology, such as millimeter wave (mmWave). In the IAB nodes, RAT resources (e.g., a set of time and / or frequency resources) can be shared between the access and backhaul networks (e.g., between communications on the access and backhaul networks). Further, for example, the DU function of an IAB node can have an assigned identifier, such as a NR cell global identifier (NR-CGI). For example, the NR-CGI can include a public land mobile identifier (PLMN ID) and a NR cell identifier (NCI). The NCI can include a gNB identifier (e.g., an identifier associated with or defined for a gNB, where the gNB can be an IAB donor node) and a local cell identifier. For example, based on the NR-CGI generated from this combination of identifiers, the NR-CGI can be unique for each DU function within the IAB network. The DU function of an IAB node can also have a physical cell identifier (PCI), which can be limited to a certain number of values and can not be unique.

[0022] Aspects described herein relate to associating an IAB node with different IAB donor nodes, which can include modifying an IAB node that can be in communication with a first upstream IAB donor node to instead be in communication with a second upstream IAB donor node. In this regard, modifying the IAB node can also include at least updating an identifier (e.g., NR-CGI) associated with the IAB node. For example, an IAB node can switch from one IAB donor node to another IAB donor node during times of high interference, high load, etc. for the IAB node and / or in cases where the IAB node is mobile, and can select different IAB donor nodes as it moves within a coverage area of an IAB network. In these examples, the MT functionality of the IAB node can select different IAB donor nodes, which can be due to selecting different upstream IAB nodes connected to different IAB donor nodes. In one example, based on selecting a different IAB donor node (which has a different gNB identifier than a previous IAB donor node), the IAB node can establish a different DU functionality associated with the different gNB identifier, where the different DU functionality can accordingly have a different NR-CGI than the previous DU functionality. Further, the IAB node can trigger one or more child nodes to associate with or migrate to the different DU functionality to provide network access to the one or more child nodes via the different IAB donor node. This can allow the IAB node to communicate with different IAB donor nodes and handle transmissions to child nodes without causing radio link failures or other disruptions in communication to the child nodes. This in turn can improve network connectivity, efficiency, and user experience for the child nodes.

[0023] Reference will be made below to Figures 1-5 The described features will be presented in greater detail.

[0024] As used in this application, the terms "component," "module," "system" and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and / or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and / or thread of execution and a component can be localized, both within a single computer and / or distributed across

[0025] The techniques described herein can be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other systems. The terms "system" and "network" are often used interchangeably. A CDMA system can implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95 and IS-856 standards. IS-2000 Versions 0 and A are commonly referred to as CDMA2000 IX, IX, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 lxEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system can implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA system can implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, UMTS, LTE and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). CDMA2000 IX, IX, UMB, HRPD, and GSM are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein can be used for the wireless networks and radio technologies mentioned above, as well as other wireless networks and radio technologies. For clarity, the following description will refer to techniques for LTE, which is an example of a wireless communication system that can benefit from the techniques described herein. TMThe teachings herein can be implemented in hardware and / or in software, including as a computer program product. The software implementation can be implemented by using any operating system or standalone software systems using technologies including, for example, Java, C++, or C-Sharp and / or others. The teachings herein can be implemented as part of the software and / or hardware of one or more electronic devices, such as an access point, a base station, a user equipment, a mobile device, a wireless communication device, a desktop computer, a laptop computer, a tablet computer, a processor, or other computing systems, or as instructions stored on non-transitory computer-readable media, which can be included in a computer program product.

[0026] The following description provides examples, and is not intended to limit or restrict the scope, applicability or description in the claims. Changes can be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples can omit, substitute, or add various procedures or components as appropriate. For instance, the methods described can be performed in an order different than described, and other steps can be added, omitted, or combined. Also, features described with respect to some examples can be combined in other examples.

[0027] Various aspects or features will be presented in terms of systems, which can include a number of devices, components, modules, and the like. It is to be understood and appreciated that the various systems can include additional devices, components, modules, etc. and / or can not include all of the devices, components, modules etc. discussed in connection with the figures. A combination of these approaches can also be used.

[0028] Figure 1 FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100. The wireless communications system (also referred to as a wireless wide area network (WWAN)) can include base stations 102, UEs 104, an evolved packet core (EPC) 160, and / or a 5G core (5GC) 190. The base stations 102 can include macro cells (high power cellular base stations) and / or small cells (low power cellular base stations). The macro cells can include base stations. The small cells can include femtocells, picocells, and microcells. In one example, the base stations 102 can also include gNBs 180, as described further herein.

[0029] The base stations 102 configured for 4G LTE (which can collectively be referred to as the Evolved Universal Mobile Telecommunication System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with the EPC 160 through backhaul links 132 (e.g., using an SI interface). The base stations 102 configured for 5G NR (which can collectively be referred to as the Next Generation RAN (NG-RAN)) can interface with the 5GC 190 through backhaul links 184. In addition to other functions, the base stations 102 can perform one or more of the following functions: transfer of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 can communicate directly or indirectly (e.g., through the EPC 160 or 5GC 190) with each other over backhaul links 134 (e.g., using an X2 interface). The backhaul links 134 can be wired or wireless.

[0030] The base stations 102 can wirelessly communicate with one or more UEs 104. Each of the base stations 102 can provide communication coverage for a respective geographic coverage area 110. There can be overlapping geographic coverage areas 110. For example, a small cell 102' can have a coverage area 110' that overlaps with one or more macrocells 102. A network that includes both small cell and macrocells can be known as a heterogeneous network. A heterogeneous network can also include Home Evolved Node Bs (eNBs) (HeNBs), which can provide service to a restricted group known as a closed subscriber group (CSG). The communication links 120 between the base stations 102 and the UEs 104 can include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and / or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 can use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication links can be through one or more carriers, and each carrier can be a band of frequency waves having a corresponding bandwidth. The base stations 102 / UEs 104 can use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (e.g., 100, 200, 400, 600, or 800 MHz) in

[0031] In another example, certain UEs 104 can communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 can use DL / UL WWAN spectrum. The D2D communication link 158 can use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication can be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on IEEE 802.11 standards, LTE, or NR.

[0032] The wireless communications system can also include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 / AP 150 can perform clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

[0033] The small cells 102' can operate in a licensed and / or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cells 102' can employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cells 102' employing NR in an unlicensed frequency spectrum can boost coverage and / or increase capacity for access networks.

[0034] The base stations 102, whether small cell 102' or large cell (e.g., macro base station), can include an eNB, gNodeB (gNB), or other types of base station. Some base stations, such as gNB 180 can operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and / or near mmW frequencies in communication with the UEs 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 can be referred to as a mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range from 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in this band can be referred to as a millimeter wave. Near mmW can extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW / near mmW radio frequency band have extremely high path loss and short range. The mmW base station 180 can utilize beamforming 182 with the UEs 104 to compensate for the extremely high path loss and short range. The base station 102 referred to herein can include a gNB 180.

[0035] The EPC 160 can include a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, a multimedia broadcast multicast service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and a packet data network (PDN) gateway 172. The MME 162 can be in communication with a home subscriber server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the serving gateway 166, which itself is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation as well as other functions. The PDN gateway 172 and the BM-SC 170 are connected to the IP services 176. The IP services 176 can include the Internet, an intranet, an IP multimedia subsystem (IMS), a packet switched (PS) streaming service, and / or other IP services. The BM-SC 170 can provide functions for MBMS user service provisioning and

[0036] The 5GC 190 can include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. The AMF 192 can be in communication with a unified data management (UDM) 196. The AMF 192 can be the control node that processes the signaling between the UEs 104 and the 5GC 190. Generally, the AMF 192 can provide QoS flow and session management. User Internet protocol (IP) packets (e.g., from one or more UEs 104) are transferred

[0037] A base station can also be referred to as a gNB, Node B, evolved Node B (eNB), an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit reception point (TRP), or some other suitable terminology. A base station 102 provides an access point to the EPC 160 or 5GC 190 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, or any other similar functional device. Some of the UEs 104 can be referred to as IoT devices (e.g., a parking meter, a gas pump, a toaster, a vehicle, a heart monitor, etc.). IoT UEs can include machine type communication (MTC) / enhanced MTC (eMTC, also referred to as category (CAT)-M, category Ml) UEs, NB-IoT (also referred to as category NB1) UEs, and other types of UEs. In the present disclosure, eMTC and NB-IoT can refer to future technologies that can evolve from or can be based on these technologies. For example, eMTC can include FeMTC (further eMTC), eFeMTC (enhanced further eMTC), mMTC (massive MTC), etc., and NB-IoT can include eNB-IoT (enhanced NB-IoT), FeNB-IoT (further enhanced NB-IoT), etc. A UE 104 can also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

[0038] As described in the examples herein, wireless communication access network 100 can provide a framework for an IAB network. In an example, IAB can include an access network between IAB nodes and UEs and a backhaul network between IAB nodes. An IAB network can generally include anchor nodes including IAB nodes with a wired or other connection to a network (e.g., to an EPC), which are referred to as IAB donor nodes, and one or more IAB nodes that can relay traffic from / to an anchor node via one or more hops between IAB nodes, which can be referred to as layer 2 relay nodes. An IAB network can use a similar framework as wireless communication access network 100, where base station 102 can be an anchor node to an EPC (and / or can be an IAB donor node, can provide connectivity for an IAB donor, or can be similar to a DU functionality of an IAB node), and UE 104 can be a UE or MT functionality of an IAB node that relays traffic from an anchor node to other UEs. In this example, UE 104 used as an IAB node can include 1) a DU functionality to communicate with one or more UEs or downstream IAB nodes (e.g., by transmitting on a downlink and receiving on an uplink), and 2) a MT functionality to communicate with an IAB donor node and / or one or more upstream IAB nodes (e.g., by transmitting on an uplink and receiving on a downlink). As described, an IAB network can share radio resources (e.g., time and / or frequency resources) between an access network and a backhaul network, and can operate using a 5G NR RAT. Figure 2 One specific example of an IAB network is shown in FIG. 2.

[0039] Referring to Figure 2 In accordance with various aspects described herein, another example of a wireless communication access network 200 that can provide IAB functionality is depicted. Wireless communication access network 200 can include one or more IAB donor nodes 202, one or more IAB nodes 204, which can communicate with IAB donor nodes 202 and / or other IAB nodes 204 to facilitate communication between one or more UEs 206 and IAB donor nodes 202. Generally, as used herein, a downstream node can refer to a node that is downstream (e.g., closer to a UE) from a connected upstream node. For example, IAB node 204 is a downstream node of IAB donor 1 202. Similarly, as used herein, an upstream node can refer to a node that is upstream (e.g., closer to a network) from a connected downstream node. For example, IAB donor 1 202 is an upstream node of IAB node 204. Additionally, a node can generally transmit to its downstream nodes on a downlink, and / or can generally receive from its downstream nodes on an uplink.

[0040] In one example, the IAB donor node 202 can include a wired connection to a network (e.g., to one or more backend network components, such as one or more components in the EPC 160, as described in Figure 1 ). In one example, the IAB donor node 202 can be or can provide similar functionality as the base station 102. The IAB donor node 202 can provide CU functionality, which can maintain radio resource control (RRC) layer, packet data convergence protocol (PDCP) layer, and / or similar layer functionality, and DU functionality, which can maintain radio link control (RLC) layer, medium access control (MAC) layer, physical (PHY) layer, and / or similar layer functionality. The IAB node 204 can provide DU and MT functionality, as described. In this regard, the IAB node 204 can communicate with the IAB donor node 202 or other upstream IAB nodes using the MT functionality, which is controlled and scheduled by the IAB donor node 202 or other upstream IAB nodes 204 (e.g., by the DU) as a parent node is connected and can use backhaul links. For example, the connection and / or communication between the IAB node 204 and the IAB donor node 202 (and / or between the IAB node 204 and another upstream IAB node 204) can be similar to the connection and communication between the UE 104 and the base station 102, respectively, as described in Figure 1 . Additionally, the IAB node 204 can also communicate with one or more UEs 206 or other downstream IAB nodes 204 using the DU functionality, which can provide similar functionality as the base station 102, including scheduling communications for the UEs 206 and / or other downstream IAB nodes 204 connected as child nodes and controlling access links and backhaul links under its coverage, for example. In one example, the IAB node 204 can provide the DU functionality to communicate with the UEs 206 and can use the MT functionality to provide access to the CU functionality of the IAB donor node 202 via zero or multiple hops to other IAB nodes 202.

[0041] Further, the IAB donor node 202 or IAB node 204 can provide (e.g., via a DU function) one or more cells for communicating with downstream nodes. Each of the one or more cells can have a cell identifier, which can include a NR-CGI that can uniquely identify a cell in an IAB network. For example, the NR-CGI can include a PLMN ID (which can be 24 bits) and a NCI (which can be 36 bits in 5G NR), or be generated from or include the PLMN ID and NCI, where the PLMN ID can be formed from a mobile country code (MCC, which can be 12 bits) and a mobile network code (MNC, which can be 12 bits), and the NCI can be formed from a gNB identifier (e.g., the leftmost 22 to 32 bits) and a local cell identifier (e.g., in 5G NR, the remaining bits for a total of 36 bits). The gNB-ID can be unique within a gNB, and thus can be common to all cells (e.g., at IAB donor DUs and IAB node DUs) served by a gNB (with one IAB donor CU). Similarly, the PLMN + gNB-ID can globally identify a gNB. Additionally, each cell can have a physical cell identifier (PCI), which can be defined in 5G NR as one of a total of 1008 supported values. Thus, for example, a PCI can be reused by multiple geographically separated cells in a network. Cells with the same PCI can be distinguished by their unique cell global identifier (e.g., NR cell global identifier in 5G, cell global identity (CGI) in LTE, etc.). A cell can broadcast the PCI in a synchronization signal block (SSB) through a primary synchronization signal (PSS) / secondary synchronization signal (SSS) as defined in 5G NR, and the PCI can be used to determine scrambling sequences for many physical signals / channels. For example, for a primary broadcast channel (PBCH), physical downlink control channel (PDCCH), control resource set (CORESET) 0, or cell-specific physical downlink shared channel (PDSCH) transmissions sent by a cell, only the PCI can be used as a scrambling seed as defined in 5G NR; while for other channels, a configured scrambling seed can be supported in addition to the PCI. In an example, the IAB node 204 can include a modem 340 and / or a node association component 342 that associates with different donor nodes in accordance with aspects described herein.

[0042] Turning now to Figures 3-5 aspects in dashed line can be optional. Although the following describes various actions or operations that can be performed by one or more components and methods, it is understood that the following Figure 4The operations described in this specification can be implemented as operations performed by a processor on data stored on one or more computer-readable storage media, where the operations include the specific operations described in this specification, and / or where the operations also include, for example, one or more of the following:

[0043] Referring to Figure 3 One example of an implementation of the IAB node 204 can include a variety of components, some of which have already been described and are further described in this document, including components such as one or more processors 312 and memory 316 and transceiver 302 that are in communication, via one or more buses 344, which can operate in conjunction with modem 340 and / or node association components 342 to implement one or more of the functions described in this document related to associating with different donor nodes.

[0044] In an aspect, the one or more processors 312 can include and / or be part of the modem 340 that uses one or more modem processors. Thus, the various functions related to node association components 342 can be included in the modem 340 and / or the processors 312 and, in an aspect, can be executed by a single processor, while in other aspects, different ones of the functions can be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors 312 can include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receive processor, or a transceiver processor associated with the transceiver 302. In other aspects, some of the features of the one or more processors 312 and / or the modem 340 associated with the node association components 342 can be performed by the transceiver 302.

[0045] Moreover, the memory 316 can be configured to store data used by at least one of the processors 312 and / or local versions of the applications 375, or the node association component 342 and / or one or more of its subcomponents, used herein. The memory 316 can include any type of computer-readable medium usable by a computer or the at least one processor 312, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. For example, in an aspect, the memory 316 can be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining, and / or used by the at least one processor 312 to operate the node association component 342 and / or one or more of its subcomponents, and / or data associated therewith, when the IAB node 204 is operating the at least one processor 312 to execute the node association component 342 and / or one or more of its subcomponents.

[0046] The transceiver 302 can include at least one receiver 306 and at least one transmitter 308. The receiver 306 can include hardware, firmware, and / or software codes executable by a processor for receiving data, the codes including instructions and being stored in a memory (e.g., computer-readable medium). The receiver 306 can be, for example, a radio frequency (RF) receiver. In an aspect, the receiver 306 can receive signals transmitted by an upstream node, a downstream node, etc. Further, the receiver 306 can process such received signals, and also can obtain measurements of the signals, such as, but not limited to, Ec / Io, SNR, RSRP, RSSI, etc. The transmitter 308 can include hardware, firmware, and / or software codes executable by a processor for transmitting data, the codes including instructions and being stored in a memory (e.g., computer-readable medium). A suitable example of the transmitter 308 can including, but not limited to, an RF transmitter.

[0047] Further, in one aspect, the IAB node 204 can include a RF front end 388 that can operate in communication with the one or more antennas 365 and the transceiver 302 to receive and transmit radio transmissions, such as wireless communications transmitted by the at least one base station 102 or wireless transmissions transmitted by the IAB node 204. The RF front end 388 can be connected to the one or more antennas 365 and can include one or more low-noise amplifiers (LNAs) 390, one or more switches 392, one or more power amplifiers (PAs) 398, and one or more filters 396 for transmitting and receiving RF signals.

[0048] In an aspect, LNA 390 can amplify a received signal at a desired output level. In an aspect, each LNA 390 can have a specified minimum and maximum gain values. In an aspect, RF front end 388 can use one or more switches 392 to select a particular LNA 390 and its specified gain value based on a desired gain value for a particular application.

[0049] Further, for example, RF front end 388 can use one or more PA(s) 398 to amplify a signal for an RF output at a desired output power level. In an aspect, each PA 398 can have a specified minimum and maximum gain values. In an aspect, RF front end 388 can use one or more switches 392 to select a particular PA 398 and its specified gain value based on a desired gain value for a particular application.

[0050] Further, for example, RF front end 396 can use one or more filters 396 to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, a respective filter 396 can be used to filter an output from a respective PA 398 to produce an output signal for transmission. In an aspect, each filter 396 can be connected to a particular LNA 390 and / or PA 398. In an aspect, RF front end 388 can use one or more switches 392 to select a transmission or reception path using a specified filter 396, LNA 390, and / or PA 398 based on a configuration as specified by transceiver 302 and / or processor 312.

[0051] As such, transceiver 302 can be configured to transmit and receive wireless signals through one or more antennas 365 via RF front end 388. In an aspect, transceiver 302 can be tuned to operate at specified frequencies such that IAB node 204 can communicate with, for example, one or more upstream nodes, or one or more cells associated with one or more upstream nodes, one or more DUs, etc. In an aspect, for example, modem 340 can configure transceiver 302 to operate at a specified frequency and power level based on a configuration of IAB node 204 and a communication protocol used by modem 340.

[0052] In an aspect, modem 340 can be a multi-band, multi-mode modem that can process digital signals and communicate with transceiver 302 such that digital data is transmitted and received using transceiver 302. In an aspect, modem 340 can be multi-band and can be configured to support multiple frequency bands for a particular communication protocol. In an aspect, modem 340 can be multi-mode and configured to support multiple operating networks and communication protocols. In an aspect, modem 340 can control one or more components of IAB node 204 (e.g., RF front end 388, transceiver 302) based on a specified modem configuration to enable transmission and / or reception of signals from a network. In an aspect, the modem configuration can be based on a mode of the modem and a frequency band in use. In another aspect, the modem configuration can be based on configuration information associated with IAB node 204 as provided by the network during cell selection and / or cell reselection or initial access.

[0053] In an aspect, processor 312 can correspond to one or more processors described in connection with base stations and / or UEs in Figure 5 to provide MT functionality 360 or DU functionality 362 / 364, as described. Similarly, memory 316 can correspond to a memory described in connection with base stations and / or UEs in Figure 5 to provide MT functionality 360 or DU functionality 362 / 364, as described. Further, for example, transceiver 302 can include various transmission and / or reception hardware described in connection with base stations and / or UEs in Figure 5 to provide MT functionality 360 or DU functionality 362 / 364, as described. Additionally, for example, modem 340 can include a transmission or reception modem described in connection with base stations and / or UEs in Figure 5 to provide MT functionality 360 or DU functionality 362 / 364, as described. Further, in an example, antenna 365 can include a transmission or reception antenna described in connection with base stations and / or UEs in Figure 5 to provide MT functionality 360 or DU functionality 362 / 364, as described. Further, in an example, antenna 365 can include a transmission or reception antenna described in connection with base stations and / or UEs in

[0054] Additionally, for example, the node association component 342 can include an MT management component 352 to manage one or more MT functions (e.g., MT function 360) of the IAB node 204 to communicate with one or more parent DUs (e.g., parent DUs 366 and / or 368, which can be part of an upstream IAB node and / or an IAB donor node), a DU management component 354 to manage one or more DU functions (e.g., DU functions 362 and / or 364) of the IAB node, and / or a child node management component 356 to manage one or more child or downstream nodes (e.g., another IAB node, UE 206, etc.) of the IAB node 204. In an example, the IAB node 204 can communicate with the parent DU 366 via the MT function 360, where the parent DU 366 can communicate with the IAB donor CU 370 through zero or more additional IAB nodes. In another example, the IAB node 204 can additionally or alternatively communicate with the parent DU 368 via the MT function 360, where the parent DU 368 can communicate with the IAB donor CU 372, which is different from the IAB donor CU 370. Further, in examples as described further herein, the IAB node 204 can provide the DU function 362 to facilitate access to the IAB donor CU 370 by one or more downstream nodes, and / or can provide the DU function 364 to facilitate access to the IAB donor CU 372 by one or more downstream nodes.

[0055] As described, for example, the IAB donor CUs 370, 372 can be part of different IAB donor nodes, where the different IAB donor nodes can be associated with different cell groups. For example, each IAB donor node (or CU 370, 372) can provide a cell group via a base station (or DU) associated with the IAB donor node.

[0056] Figure 4 A flow diagram illustrating an example of a method 400 for associating an IAB node with different IAB donor nodes, in accordance with aspects described herein, is shown. In an example, the IAB node 204 can perform the functions described in the method 400 using one or more of the components described in Figure 2 and 3

[0057] ​In the method 400, at block 402, the MT functionality can receive a first indication to migrate from a first IAB-donor node associated with a first cell group to a second IAB-donor node associated with a second cell group. In one aspect, the MT management component 352, e.g., in conjunction with processor(s) 312, memory 316, transceiver 302, mode association component 342, etc., can receive, by the MT functionality 360, a first indication to migrate from a first IAB-donor node (or associated IAB-donor CU) associated with a first cell group to a second IAB-donor node (or associated IAB-donor CU) associated with a second cell group. For example, the MT functionality 360 can receive the first indication from the IAB-donor node via the parent (or upstream) DU 366 (e.g., via RRC signaling). For example, the parent DU functionality 366 can receive the first indication from the IAB-donor node (e.g., via Fl-C signaling), etc.

[0058] In one example, the first indication can indicate a handover from a first IAB-donor node associated with the IAB-donor CU 370 to a second IAB-donor node associated with the IAB-donor CU 372. In another example, the first indication can indicate an addition of a cell group served by the parent DU 368 and / or the second IAB-donor node associated with the IAB-donor CU 372 as a secondary cell group (e.g., in multi-connectivity or dual connectivity). In this example, a first cell group served by the parent DU 366 and / or the first IAB-donor node associated with the IAB-donor CU 372 can be a primary cell group.

[0059] In another example, the first indication can indicate an addition of a cell group served by the parent DU 368 and / or the second IAB-donor node associated with the IAB-donor CU 372 as a secondary cell group (e.g., in multi-connectivity or dual connectivity). In this example, a first cell group served by the parent DU 366 and / or the first IAB-donor node associated with the IAB-donor CU 372 is also a secondary cell group. Additionally, in this example, the first indication can indicate a release of the first cell group served by the parent DU 366 and / or the first IAB-donor node associated with the IAB-donor CU 370 as a secondary cell group.

[0060] In yet another example, the first indication can indicate a handover of a cell group served by the parent DU 368 and / or by the second IAB-donor node associated with the IAB-donor CU 372 to a primary cell group and a handover of a first cell group served by the parent DU 366 and / or by the first IAB-donor node associated with the IAB-donor CU 370 to a secondary cell group.

[0061] In the method 400, at block 404, based on receiving the first indication, a first random access procedure can be performed to connect to a second cell group associated with a second IAB donor node. In an aspect, the MT management component 352, e.g., in conjunction with the processor 312, the memory 316, the transceiver 302, the mode association component 342, etc., can perform a first random access procedure, based on receiving the first indication, to connect with a second cell group associated with a second IAB donor node. For example, the MT management component 352 can perform a first random access procedure with a second cell group and / or a second IAB donor node (associated with the IAB donor CU 372) based on the first indication received from the parent DU 366 or the first IAB donor node (associated with the IAB donor CU 370). In one example, performing the random access procedure with the second cell group and / or the second IAB donor node can be similar to a regular handover to the second cell group, or similar to adding the second cell group as a secondary cell group, switching the second cell group to a primary cell group, etc., as described, which can be based on, specified by, etc., the first indication.

[0062] For example, at block 404, when performing the first random access procedure, optionally at block 406, the first random access procedure can be performed to handover from the first cell group to the second cell group. In an aspect, the MT management component 352, e.g., in conjunction with the processor 312, the memory 316, the transceiver 302, the mode association component 342, etc., can perform the first random access procedure to handover from the first cell group to the second cell group. For example, the MT management component 352 can perform a four-step random access procedure or a two-step random access procedure, either of which can be contention-based or contention-free. Additionally, the MT management component 352 can perform the random access procedure as part of a handover, adding a cell group as a secondary cell group, switching a secondary cell group to a primary cell group, etc.

[0063] For example, a conventional handover can include the source gNB initiating the handover and sending a handover request to the target gNB over an Xn interface, where the target gNB can perform admission control and provide a new RRC configuration to the source gNB as part of a handover request acknowledgement. The source gNB can provide the RRC configuration to the UE by forwarding the RRCReconfiguration message received in the handover request acknowledgement. In this example, the UE can move the RRC connection to the target gNB (e.g., by performing a random access procedure with it) and can reply with an RRCReconfigurationComplete. The target gNB can send a UE context release to inform the source gNB that the handover was successful. In a particular example, the MT management component 352 can perform a random access procedure (e.g., at block 404) as part of a handover procedure similar to a conventional handover. For example, the first cell group or first IAB donor node (associated with the IAB donor CU 370) can perform similar functionality to the source gNB described above, the second cell group or second IAB donor node (associated with the IAB donor CU 372) can perform similar functionality to the target gNB described above, and / or the IAB node 204 (e.g., via the MT functionality 360) can perform similar functionality to the UE described above, performing the random access procedure as part of the handover.

[0064] In another example, the first random access procedure can be performed to activate or add the second cell group as a secondary cell group, optionally at block 408 when performing the first random access procedure at block 404. In an aspect, the MT management component 352, e.g., in conjunction with the processor(s) 312, memory 316, transceiver 302, mode association component 342, etc., can perform the first random access procedure to activate or add the second cell group as a secondary cell group. In one example, the MT management component 352 can be in communication with the first cell group as a primary cell group in a multi-connectivity (or dual connectivity), and can perform the random access procedure to add the second cell group as a secondary cell group. In another example, the MT management component 352 can be in communication with the first cell group as a secondary cell group in a multi-connectivity (or dual connectivity), and can perform the random access procedure to add the second cell group as an additional secondary cell group and / or to activate the second cell group as a secondary cell group instead of the first cell group (e.g., and / or can release the first cell group as a secondary cell group).

[0065] In another example, the first random access procedure can be performed to switch the second cell group as the master cell group, optionally at block 410, when performing the first random access procedure at block 404. In an aspect, the MT management component 352, e.g., in conjunction with the processor 312, memory 316, transceiver 302, mode association component 342, etc., can perform the first random access procedure to switch the second cell group as the master cell group (e.g., in multi-connectivity or dual connectivity). In this example, the MT management component 352 can also switch the first cell group as the secondary cell group.

[0066] In the method 400, at block 412, a second DU function to serve a fourth cell group can be established based on performing the first random access procedure in addition to the first DU function to serve the third cell group. In an aspect, the DU management component 354, e.g., in conjunction with the processor 312, memory 316, transceiver 302, mode association component 342, etc., can establish a second DU function (e.g., DU function 364) to serve a fourth cell group based on the MT function 360 performing the first random access procedure in addition to the first DU function (e.g., DU function 362) to serve the third cell group. The DU management component 354 can establish the second DU function 364 served by the second cell group and / or a second IAB donor node (associated with the IAB donor CU 372). The DU management component 354 can establish the second DU function 364 because parameters of the DU function can change based on being associated with or served by the second cell group and / or the second IAB donor node (associated with the IAB donor CU 372). For example, the second cell group can have or be associated with a different identifier (e.g., gNB identifier) than the first cell group, and thus the second DU function 364 can be established to advertise a different DU identifier (e.g., different NCGI including a different gNB identifier) associated with the second cell group. In another example, the second DU function 364 can also be established with a different PCI than the first DU function 362 to differentiate signaling with the DU functions 362, 364 (e.g., to avoid PCI collision in a mobile IAB node scenario). In any case, establishing the second DU function can allow one or more child nodes to establish a connection with the second DU function, whether a new connection or a connection moved from the first DU function, etc.

[0067] As described, DU functionality can include backhaul connections for IAB nodes that provide DU functionality to an IAB donor CU as well as over-the-air broadcast or access network connections to downstream nodes. In one example, as described herein, the DU management component 354 can instantiate multiple DU functionalities by having an IAB node have multiple Fl connections with different CUs (e.g., one Fl connection with the IAB donor CU 370 and a different Fl connection with the IAB donor CU 372), where each DU functionality can be associated with one of the Fl connections. In this example, the DU management component 354 can or can not broadcast cell identifiers for each DU functionality. In one example, based on establishing the second DU functionality 364, the IAB node 204 can remove the first DU functionality 362 (e.g., in the case of a handover). This can include the DU management component 354 broadcasting only the cell identifiers for the cells or cell groups of the second DU functionality 364. In another example, the IAB node 204 can maintain the first DU functionality 362 and the second DU functionality 364 at least for a period of time (e.g., in the case or example of multiple connections described above). This can include the DU management component 354 broadcasting the cell identifiers for the cells (or cell groups) of the first DU functionality 362 and the second DU functionality 364. In one example, the IAB node 204 can maintain the first DU functionality 362 until all child nodes have been moved (e.g., handed over) to the second DU functionality 364.

[0068] In method 400, at block 414, a second random access procedure can be triggered for a child node based on establishing the second DU function. In an aspect, child node management component 356, e.g., in conjunction with processor(s) 312, memory 316, transceiver 302, mode association component 342, etc., can trigger a second random access procedure for a child node based on establishing the second DU function. For example, the child node can comprise a UE 206, one or more downstream IAB nodes, etc. In an example, child node management component 356 can trigger the second random access procedure for the child node to cause the child node to establish a connection with the second DU function 364. As described above with respect to the first random access procedure, the second random access procedure triggered for the child node can similarly be part of a handover from a third cell group associated with the first DU function 362 to a fourth cell group associated with the second DU function 364, activating or adding the fourth cell group associated with the second DU function 364 as part of a secondary cell group, switching the fourth cell group associated with the second DU function 364 as a primary cell group (and / or switching the third cell group associated with the first DU function 362 as a secondary cell group), etc. In one example, upon triggering the second random access procedure, child node management component 356 can indicate an identifier (e.g., NCGI, PCI, etc.) of the second DU function 364 to the child node, which the child node can use in performing the second random access procedure (e.g., to identify the second DU function 364).

[0069] In method 400, optionally at block 416, the MT function can additionally receive a second indication to migrate the child node from the first IAB donor node to the second IAB donor. In an aspect, MT management component 352, e.g., in conjunction with processor(s) 312, memory 316, transceiver 302, mode association component 342, etc., can receive, by the MT function 360, a second indication to migrate a child node (e.g., one or more UEs 206 or downstream IAB nodes) from a first IAB donor node (or associated IAB donor CU) associated with a first cell group to a second IAB donor node (or associated IAB donor CU) associated with a second cell group. For example, MT management component 352 can receive the second indication from the first IAB donor node (or associated IAB donor CU), the second IAB donor node (or associated IAB donor CU), etc. In an example, MT management component 352 can additionally perform the first random access procedure based on receiving the second indication, DU management component 354 can additionally establish the second DU function based on receiving the second indication, etc.

[0070] Further, for example, triggering the second random access procedure for the child node at block 414 can optionally include forwarding the second indication to the child node at block 418. In an aspect, the DU management component 354, e.g., in conjunction with the processor 312, the memory 316, the transceiver 302, the mode association component 342, etc., can forward the second indication to the child node. For example, the DU management component 354 can transmit the second indication to the child node in RRC signaling. The first indication and / or the second indication can be a conditional indication indicating one or more conditions for determining to establish the second DU and / or to migrate the UE to the second DU, etc.

[0071] In the method 400, optionally at block 420, a cell identifier of the second DU functionality can be broadcasted. In an aspect, the DU management component 354, e.g., in conjunction with the processor 312, the memory 316, the transceiver 302, the mode association component 342, etc., can broadcast the cell identifier of the second DU functionality. For example, the DU management component 354 can broadcast the NCGI and / or PCI of the second DU functionality 364 and / or the first DU functionality 362. For example, the DU management component 354 can broadcast the NCGI and / or PCI in the first cell or the second cell in broadcast signaling, on a broadcast channel, in system information, etc. This can allow the child node (e.g., the UE 206) to identify the second DU functionality 364 to migrate to. For example, the DU management component 354 can use the PCI when transmitting PSS / SSS in SSB, for scrambling PBCH, PDCCH, CORESET 0, cell-specific PDSCH transmissions, etc.

[0072] In the method 400, optionally at block 422, based on performing the handover from the first cell group to the second cell group, a connection with the first cell group can be released or the first cell group can be deactivated. In an aspect, the DU management component 354, e.g., in conjunction with the processor 312, the memory 316, the transceiver 302, the mode association component 342, etc., can release a connection with the first cell group or deactivate the first cell group based on performing the handover from the first cell group to the second cell group.

[0073] According to examples described herein, an IAB node can have a first signaling connection to a first donor CU and can be served by a first cell group comprising a first cell and associated with a first IAB donor. A first child node of the IAB node can be served by a second cell group at the IAB node DU, the second cell group comprising a second cell and associated with the first IAB donor. The IAB node can receive a first message for the IAB node MT and a second message for the first child node to migrate to a second IAB donor. The IAB node can perform a first random access procedure and connect to a third cell group comprising a third cell and associated with the second IAB donor based on the first message. The IAB node can switch a first functionality of the IAB node DU after successfully completing the first random access procedure, based on which the IAB node DU can serve a fourth cell group comprising a fourth cell and associated with the second IAB donor. The IAB node can trigger or complete a second random access procedure for the first child node based on a second reconfiguration message, based on which the first child node can be served by at least a fourth cell of the fourth cell group.

[0074] Further, in one example, the first signaling connection can be Fl-C or RRC. The first child node can be a second IAB node comprising a MT or a UE. The first message or the second message can be an RRC reconfiguration message or an RRC connection reconfiguration message. The first cell group and the third cell group can be a source cell group and a target cell group, respectively, where the IAB node MT can perform a handover from a source gNB comprising the first IAB donor to a target gNB comprising the second IAB donor based on the first message, and / or can release the first cell group. The first cell group and the third cell group can be a source secondary cell group and a target secondary cell group, respectively, where the IAB node MT can perform a secondary node change from a source secondary node (SN)-gNB comprising the first IAB donor to a target SN-gNB comprising the second IAB donor based on the first message that can be received from a MN, and / or can release the first cell group. The first cell group can be a primary cell group, and the third cell group can be a secondary cell group, where the IAB node MT can perform a secondary node addition to a SN-gNB comprising the second IAB donor based on the first message, in which case a first gNB comprising the first IAB donor can be a master node (MN)-gNB, and the IAB node MT can not release at least a first cell in the first cell group when adding the third cell group. The IAB node MT can perform a MN / SN handover, where the third cell group and the first cell group can become a primary cell group and a secondary cell group, respectively (and where the third gNB and the first gNB can become a MN-gNB or a SN-gNB, respectively).

[0075] Further, for example, the first and third cell groups can be first and second secondary cell groups, respectively, where the IAB node MT can perform a secondary node addition of a second SN-gNB including a second IAB donor based on the first message, in which case the first gNB including the first IAB donor can be the first SN-gNB, and the IAB node MT can not release at least the first cell of the first cell group when adding the third cell group. The first and third cell groups can be first and second secondary cell groups, respectively, where the IAB node MT can activate at least a third cell of the third cell group based on the first message, which can be received from the MN. The first node can set a status of at least the first cell of the first cell group to deactivated or dormant. The IAB node can include at least two MTs, and the first message can be for a first MT of the IAB node. The first message can carry a conditional configuration (e.g., conditional handover command, conditional SN change, etc.), where the condition can be defined on at least one of the third cell of the third cell group or the first cell of the first cell group. The first function of switching can include broadcasting a new PCI of the fourth cell, where the second cell maintains an old PCI. The first function of switching can include broadcasting a new NCGI or NCI or gNB-ID of the fourth cell, where the second cell maintains an old NCGI or NCI or gNB-ID. The IAB node DU can continue to broadcast the identifier of the second cell after the first function of switching. As noted above, the IAB node can include two logical DUs. The first function of switching can be triggered by a MN / SN handover of the IAB node MT.

[0076] Further, for example, the second and fourth cell groups can be source and target cell groups, respectively, where the child node can perform a handover from a source gNB including a first IAB donor to a target gNB including a second IAB donor based on the second message, and / or can release the second cell group. The second and fourth cell groups can be source and target secondary cell groups, respectively, where the child node can perform a secondary node change from a source SN-gNB including the first IAB donor to a target SN-gNB including the second IAB donor based on the second message, and / or can release the second cell group. The child node can receive the second message from a MN-gNB. The second message can carry a conditional configuration (e.g., conditional handover command, conditional SN change), where the condition can be defined on at least one of a fourth cell of the fourth cell group or a second cell of the second cell group. The child node can be a second IAB node, and can switch a second function of the node DU upon successful completion of a second random access procedure.

[0077] Figure 5is a block diagram of a MIMO communication system 500 including a base station 102 (or a DU functionality of an upstream node upstream of the IAB node 204) and a UE 104 (or a MT functionality of the IAB node 204). The MIMO communication system 500 can illustrate the references Figure 1 described wireless communication access network 100. The base station 102 can be an example of aspects described with reference to the base station 102 Figure 1 described base station 102. The base station 102 can be equipped with antennas 534 and 535, and the UE 104 can be equipped with antennas 552 and 553. In the MIMO communication system 500, the base station 102 can be able to send data over multiple communication links simultaneously. Each communication link can be called a “layer” and the “rank” of the communication link can indicate the number of layers used for communication. For example, in a 2x2 MIMO communication system where base station 102 transmits two “layers,” the rank of the communication link between the base station 102 and the UE 104 is two.

[0078] At the base station 102, a transmit (Tx) processor 520 can receive data from a data source. The transmit processor 520 can process the data. The transmit processor 520 can also generate control symbols or reference symbols. A transmit MIMO processor 530 can perform spatial processing (e.g., precoding) on data symbols, control symbols, or reference symbols, if applicable, and can provide output symbol streams to the transmit modulator / demodulators 532 and 533. Each modulator / demodulator 532 to 533 can process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator / demodulator 532 to 533 can further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a DL signal. In one example, DL signals from modulator / demodulators 532 and 533 can be transmitted via the antennas 534 and 535, respectively.

[0079] The UE 104 can be an example of aspects described with reference to the UE 104 Figures 1-2Examples of aspects of the described UE 104, MT functionality of the IAB node 204, etc. At the UE 104, the UE antennas 552 and 553 can receive DL signals from the base station 102 and can provide the received signals to the modulator / demodulators 554 and 555, respectively. Each modulator / demodulator 554 to 555 can condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each modulator / demodulator 554 to 555 can further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 556 can obtain received symbols from the modulator / demodulators 554 and 555, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive (Rx) processor 558 can process (e.g., demodulate, deinterleave, and decode) the detected symbols, providing decoded data for the UE 104 to a data output, and provide decoded control information to a processor 580, or memory 582.

[0080] In some cases, the processor 580 can execute stored instructions to instantiate a node association component 342 (see, e.g., FIG. 6) for communicating with the base station 102 or other upstream node and / or communicating with one or more DUs or other downstream nodes. Figure 2 and Figure 3 In some cases, the processor 580 can execute stored instructions to instantiate a node association component 342 (see, e.g., FIG. 6) for communicating with the base station 102 or other upstream node and / or communicating with one or more DUs or other downstream nodes.

[0081] On the uplink (UL), at the UE 104, a transmit processor 564 can receive and process data from a data source. The transmit processor 564 can also generate reference symbols for a reference signal. The symbols from the transmit processor 564 can be precoded by a transmit MIMO processor 566 if applicable, further processed by the modulator / demodulators 554 and 555 (e.g., for SC-FDMA, etc.), and be transmitted to the base station 102 in accordance with the communication parameters received from the base station 102. At the base station 102, the UL signals from the UE 104 can be received by the antennas 534 and 535, processed by the modulator / demodulators 532 and 533, detected by a MIMO detector 536 if applicable, and further processed by a receive processor 538. The receive processor 538 can provide decoded data to a data output and to the processor 540 or memory 542.

[0082] In some cases, the processor 540 can execute stored instructions to instantiate a node association component 342 (see, e.g., FIG. 6) for communicating with the base station 102 or other upstream node and / or communicating with one or more DUs or other downstream nodes. Figure 2 and Figure 3 In some cases, the processor 540 can execute stored instructions to instantiate a node association component 342 (see, e.g., FIG. 6) for communicating with the base station 102 or other upstream node and / or communicating with one or more DUs or other downstream nodes.

[0083] The components of the UE 104 may be implemented individually or collectively using one or more ASICs adapted to perform some or all applicable functions in hardware. Each of the modules may be a means for performing one or more functions associated with the operation of the MIMO communication system 500. Similarly, the components of the base station 102 may be implemented individually or collectively using one or more ASICs adapted to perform some or all applicable functions in hardware. Each of the components may be a means for performing one or more functions associated with the operation of the MIMO communication system 500.

[0084] The following aspects are merely illustrative, and aspects thereof may be combined with aspects of other embodiments or teachings described herein, but are not limited thereto.

[0085] Aspect 1 is a method for wireless communication, comprising: receiving, through the MT function of the IAB node, a first indication for migrating from a first IAB donor node associated with a first cell group and a first CU to a second IAB donor node associated with a second cell group and a second CU; performing, through the IAB node and at least partially based on receiving the first indication, a first random access process to connect to the second cell group associated with the second IAB donor node; establishing, through the IAB node and based on performing the first random access process, a second DU function serving a fourth cell group in addition to the first DU function of the IAB node serving a third cell group; and triggering, based on establishing the second DU function, a second random access process for a subnode to migrate from the third cell group associated with the first DU function to the fourth cell group associated with the second DU function.

[0086] In aspect 2, the method according to aspect 1 includes at least one of the following: communicating with the first CU using an RRC connection through the MT function of the IAB node, or communicating with the first CU using an F1-C connection through the first DU function of the IAB node.

[0087] In aspect 3, the method according to any one of aspects 1 or 2 includes: wherein the child node is an MT function of the second IAB node or a UE.

[0088] In aspect 4, the method according to any one of aspects 1 to 3 includes: wherein the first indication is part of an RRC reconfiguration message or an RRC connection reconfiguration message received from the first IAB donor node.

[0089] In Aspect 5, the method of any of Aspects 1-4 includes wherein the first cell group is a source cell group and the second cell group is a target cell group for a handover, wherein performing the first random access procedure is part of performing a handover from the first cell group to the second cell group, and the method further comprises releasing a connection with the first cell group based on performing the handover from the first cell group to the second cell group.

[0090] In Aspect 6, the method of Aspect 5 includes communicating, by the IAB node, with a master cell group, wherein the first cell group and the second cell group are secondary cell groups.

[0091] In Aspect 7, the method of Aspect 6 includes receiving, from the master cell group, the first indication to migrate from the first IAB donor node to the second IAB donor node.

[0092] In Aspect 8, the method of any of Aspects 1-7 includes wherein the first cell group is a master cell group and the second cell group is a secondary cell group, wherein performing the first random access procedure is part of at least one of: performing a secondary cell addition to add the second cell group as the secondary cell group, or performing a handover of the first cell group to the secondary cell group and a handover of the second cell group to the master cell group.

[0093] In Aspect 9, the method of any of Aspects 1-8 includes communicating, by the IAB node, with a master cell group, wherein the first cell group and the second cell group are secondary cell groups, and wherein performing the first random access procedure is part of performing a secondary cell addition to add the second cell group as an additional secondary cell group.

[0094] In Aspect 10, the method of any of Aspects 1-9 includes communicating, by the IAB node, with a master cell group, wherein the first cell group and the second cell group are secondary cell groups, and wherein performing the first random access procedure is part of activating the second cell group as a single active secondary cell group, and the method further comprises deactivating the first cell group as the single active secondary cell group.

[0095] In Aspect 11, the method of Aspect 10 includes receiving, from the master cell group, the first indication to activate the second cell group as the single active secondary cell group.

[0096] In Aspect 12, the method of any of Aspects 1-11 includes wherein the IAB node comprises one or more additional MT functions.

[0097] In aspect 13, the method of any of aspects 1-12 includes wherein the first indication indicates one or more conditions for migrating from the first IAB-donor node to the second IAB-donor node.

[0098] In aspect 14, the method of aspect 13 includes wherein the one or more conditions are based on a measured signal quality of one or more of the first group of cells or the second group of cells.

[0099] In aspect 15, the method of any of aspects 1-14 includes wherein switching from the first DU function to the second DU function comprises broadcasting, by the IAB node, a second PCI of the fourth group of cells associated with the second DU function, the second PCI being different from a first PCI of the third group of cells associated with the first DU function.

[0100] In aspect 16, the method of any of aspects 1-15 includes wherein switching from the first DU function to the second DU function comprises broadcasting, by the IAB node, a second cell global identity associated with a first cell of the fourth group of cells, the second cell global identity being different from a first cell global identity associated with a second cell of the third group of cells.

[0101] In aspect 17, the method of aspect 16 includes wherein the second cell global identity comprises an NR cell identifier, a gNB identifier, a local cell identifier, or a PLMN identifier associated with the second IAB-donor node.

[0102] In aspect 18, the method of any of aspects 1-17 includes broadcasting, by the IAB node, a first identifier of the first group of cells and a second identifier of the second group of cells after switching from the first DU function to the second DU function.

[0103] In aspect 19, the method of any of aspects 1-18 includes wherein switching from the first DU function to the second DU function is based at least in part on a master node to secondary node switch of the MT function of the IAB node.

[0104] In aspect 20, the method of any of aspects 1-19 includes receiving, by the IAB node from the first IAB-donor node or the second IAB-donor node, a second indication to switch from the first DU function to the second DU function, wherein the one or more processors are configured to execute the instructions to cause the apparatus to switch from the first DU function to the second DU function, and trigger the child node to migrate from the third cell group associated with the first DU function to the fourth cell group associated with the second DU function based at least in part on the second indication.

[0105] In aspect 21, the method of aspect 20 includes wherein triggering the child node to migrate from the third cell group to the fourth cell group comprises triggering the child node to switch the third cell group to the fourth cell group.

[0106] In aspect 22, the method of aspect 21 includes wherein the third cell group and the fourth cell group are secondary cell groups configured for the child node, and the method further includes receiving an indication for the child node to release the third cell group.

[0107] In aspect 23, the method of any of aspects 20-22 includes forwarding the second indication to the child node, wherein the second indication indicates one or more conditions for migrating the child node from the first IAB-donor node to the second IAB-donor node.

[0108] In aspect 24, the method of aspect 23 includes wherein the one or more conditions are based on a measured signal quality of one or more of the third cell group or the fourth cell group.

[0109] Aspect 25 is an apparatus for wireless communication including a transceiver, a memory configured to store instructions, and one or more processors communicatively coupled with the memory and the transceiver, wherein the one or more processors are configured to execute the instructions to cause the apparatus to perform one or more of the methods of any of aspects 1-24.

[0110] Aspect 26 is an apparatus for wireless communication including means for performing one or more of the methods of any of aspects 1-24.

[0111] Aspect 27 is a computer-readable medium including code executable by one or more processors for wireless communication, the code comprising code for performing one or more of the methods of any of aspects 1-24.

[0112] The detailed description set forth above describes examples and does not represent the only examples that can be implemented or that are within the scope of the claims. The term "example" is used herein to mean "serving as an example, instance, or illustration," and not "preferred" or "advantageous over other examples." The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

[0113] Information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that can be referenced throughout the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, computer-executable code or instructions stored on computer-readable media, or any combination thereof.

[0114] The various illustrative blocks and components described in connection with the disclosure herein can be implemented or performed with a specially-programmed apparatus, such as but not limited to a processor, a digital signal processor (DSP), an ASIC, a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A specially-programmed processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, microcontroller, or state machine. A specially-programmed processor can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core or any other such configuration.

[0115] The functions described herein can be implemented in hardware, software executed by a processor, or any combination thereof. If implemented in software executed by a processor, the functions can be stored on or transmitted over as one or more instructions or code on a non-transitory computer-readable medium. Other examples and implementations are within the scope and spirit of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a specially programmed processor, hardware, hardwiring, or combinations of any of these. Features implementing functions can also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Also, as used herein, including in the claims, "or" as used in a list of items prefaced by "at least one of indicates a disjunctive list such that, for example, a list of "at least one of A, B, or C" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0116] Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media can be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0117] The foregoing description of the present disclosure has been presented for the purposes of concurrency and illustration so that those skilled in the art can make and use the present disclosure. Modifications to, and variations of, the various implementations of the present disclosure will be apparent to those skilled in the art, and, therefore, it is intended that the present disclosure be taken as including all possible modifications and variations to the aspects and concepts disclosed herein. Additionally, though the elements of which an aspect and / or embodiment has been described or claimed in singular form, the plural is contemplated unless expressly limited to only singular. Additionally, any aspect and / or embodiment of the present disclosure can be utilized in combination with any and all other aspects and / or embodiments, unless otherwise stated. The elements of which an aspect and / or embodiment has been described or claimed in singular form, the plural is contemplated unless expressly limited to only singular. Therefore, the present disclosure is not intended to be limited to the examples described herein and the conclusions drawn from the exemplary designs and implementations disclosed herein are intended to be within the scope of the present disclosure.

Claims

1. An apparatus for wireless communication, comprising: transceiver; a memory configured to store instructions; as well as one or more processors communicatively coupled to the memory and the transceiver, wherein the one or more processors are configured to execute the instructions to cause the apparatus to: receiving, by a mobile terminal (MT) function, a first indication for migration from a first integrated access and backhaul (IAB) donor node provided by a first central unit (CU) and serving the device via a first group of cells to a second IAB donor node provided by a second CU and serving the device via a second group of cells; performing a first random access procedure based at least in part on receiving the first indication to connect to the second group of cells associated with the second IAB donor node; In addition to the first distributed unit (DU) function of the apparatus providing a third cell group for serving one or more sub-nodes, establishing a second DU function of providing a fourth cell group for serving the one or more sub-nodes based on performing the first random access procedure; and Based on establishing the second DU function, a second random access procedure is triggered for the subnode to migrate from the third cell group provided by the first DU function to the fourth cell group provided by the second DU function.

2. The device according to claim 1, wherein The one or more processors are further configured to execute the instructions to cause the apparatus to perform at least one of: communicating with the first CU using a radio resource control (RRC) connection through the MT function of the IAB node, or communicating with the first CU using an F1-C connection through the first DU function.

3. The device according to claim 1, wherein The child node is an MT function of a second IAB node or a user equipment (UE).

4. The device according to claim 1, wherein The first indication is part of a radio resource control (RRC) reconfiguration message or an RRC connection reconfiguration message received from the first IAB donor node.

5. The device according to claim 1, wherein The first cell group is a source cell group and the second cell group is a target cell group for switching, wherein the one or more processors are configured to execute the instructions so that the device performs the following operations: performs the first random access procedure as part of performing switching from the first cell group to the second cell group, and wherein the one or more processors are further configured to execute the instructions so that the device performs the following operations: releases the connection with the first cell group based on performing switching from the first cell group to the second cell group.

6. The device according to claim 5, wherein The one or more processors are further configured to execute the instructions to cause the apparatus to perform the following operations: communicate with a primary cell group, wherein the first cell group and the second cell group are secondary cell groups.

7. The device according to claim 6, wherein The one or more processors are further configured to execute the instructions to cause the apparatus to receive, from the primary cell group, the first indication for migration from the first IAB donor node to the second IAB donor node.

8. The device according to claim 1, wherein The first cell group is a primary cell group and the second cell group is a secondary cell group, wherein the one or more processors are configured to execute the instructions so that the device performs the first random access procedure as part of at least one of the following: performing a secondary cell addition to add the second cell group as the secondary cell group, or performing a handover of the first cell group to the secondary cell group and a handover of the second cell group to the primary cell group.

9. The device according to claim 1, wherein The one or more processors are further configured to execute the instructions so that the apparatus performs the following operations: communicates with a primary cell group, wherein the first cell group and the second cell group are secondary cell groups, and wherein the one or more processors are configured to execute the instructions so that the apparatus performs the following operations: performs the first random access procedure as part of performing a secondary cell addition to add the second cell group as an additional secondary cell group.

10. The device according to claim 1, wherein The one or more processors are also configured to execute the instructions so that the apparatus performs the following operations: communicates with a primary cell group, wherein the first cell group and the second cell group are secondary cell groups, and wherein the one or more processors are configured to execute the instructions so that the apparatus performs the following operations: performs the first random access procedure as part of activating the second cell group as a single active secondary cell group, and also includes: deactivating the first cell group as the single active secondary cell group.

11. The device according to claim 10, wherein The one or more processors are further configured to execute the instructions to cause the apparatus to perform the following operations: receive the first indication for activating the second cell group as the single active secondary cell group from the primary cell group.

12. The device according to claim 1, wherein The apparatus comprises one or more additional MT functions.

13. The device according to claim 1, wherein The first indication indicates one or more conditions for migrating from the first IAB donor node to the second IAB donor node.

14. The device according to claim 13, wherein The one or more conditions are based on measured signal quality of one or more of the first group of cells or the second group of cells.

15. The device according to claim 1, wherein The one or more processors are configured to execute the instructions so that the device performs the following operations: switching from the first DU function to the second DU function at least in part by broadcasting a second physical cell identifier (PCI) of the fourth cell group associated with the second DU function, the second PCI being different from the first PCI of the third cell group associated with the first DU function.

16. The device according to claim 1, wherein The one or more processors are configured to execute the instructions to cause the apparatus to perform the following operations: switching from the first DU function to the second DU function at least in part by broadcasting a second cell global identifier associated with the first cell of the fourth cell group, the second cell global identifier being different from the first cell global identifier associated with the second cell of the third cell group.

17. The device according to claim 16, wherein The second cell global identity includes an NR cell identifier, a gNB identifier, a local cell identifier, or a public land mobile network (PLMN) identifier associated with the second IAB donor node.

18. The device according to claim 1, wherein The one or more processors are further configured to execute the instructions to cause the apparatus to perform the following operations: after switching from the first DU function to the second DU function, broadcast a first identifier of a cell of the third cell group and a second identifier of a cell of the fourth cell group.

19. The device according to claim 1, wherein The one or more processors are configured to execute the instructions to cause the apparatus to switch from the first DU functionality to the second DU functionality based at least in part on a primary node to secondary node switch of the MT functionality of the IAB node.

20. The device according to claim 1, wherein The one or more processors are also configured to execute the instructions so that the device performs the following operations: receives a second indication for switching from the first DU function to the second DU function from the first IAB donor node or the second IAB donor node, wherein the one or more processors are configured to execute the instructions so that the device performs the following operations: switches from the first DU function to the second DU function; and also triggers the subnode to migrate from the third cell group associated with the first DU function to the fourth cell group associated with the second DU function based at least in part on the second indication.

21. The device according to claim 20, wherein The one or more processors are configured to execute the instructions to cause the apparatus to perform the following operations: triggering the migration of the sub-node from the third cell group to the fourth cell group at least in part by triggering the sub-node to switch from the third cell group to the fourth cell group.

22. The device according to claim 21, wherein The third cell group and the fourth cell group are secondary cell groups configured for the child node, and wherein the one or more processors are further configured to execute the instructions to cause the apparatus to perform the following operations: receive an indication for releasing the third cell group for the child node.

23. The apparatus according to claim 20, wherein The one or more processors are further configured to execute the instructions to cause the apparatus to perform the following operations: forward a third indication to the child node, wherein the third indication instructs the child node to migrate to a cell of the fourth cell group associated with the second DU function.

24. The device according to claim 23, wherein The third indication is based on one or more conditions related to measured signal quality of one or more of the third cell group or the fourth cell group.

25. A method of wireless communication, comprising: Receiving, by a mobile terminal (MT) function of an integrated access and backhaul (IAB) node, a first indication for migration from a first IAB donor node provided by a first central unit (CU) and serving the IAB node via a first group of cells to a second IAB donor node provided by a second CU and serving the IAB node via a second group of cells; performing, by the IAB node and based at least in part on receiving the first indication, a first random access procedure to connect to the second group of cells associated with the second IAB donor node; In addition to a first distributed unit (DU) function of the IAB node providing a third cell group for serving one or more sub-nodes, establishing, by the IAB node and based on performing the first random access procedure, a second DU function of providing a fourth cell group for serving one or more sub-nodes; as well as Based on establishing the second DU function, a second random access procedure is triggered for the subnode to migrate from the third cell group provided by the first DU function to the fourth cell group provided by the second DU function.

26. The method of claim 25, further comprising at least one of: communicating with the first CU using a radio resource control (RRC) connection through the MT function of the IAB node, or communicating with the first CU using an F1-C connection through the first DU function of the IAB node.

27. The method according to claim 25, wherein The first cell group is a source cell group and the second cell group is a target cell group for switching, wherein the method further includes: performing the first random access procedure as part of performing switching from the first cell group to the second cell group, and wherein the method further includes: releasing the connection with the first cell group based on performing switching from the first cell group to the second cell group.

28. The method according to claim 27, wherein The method further includes communicating with a primary cell group, wherein the first cell group and the second cell group are secondary cell groups.

29. The method according to claim 28, wherein The method further includes receiving, from the primary cell group, the first indication for migration from the first IAB donor node to the second IAB donor node.

30. The method of claim 25, wherein: The first cell group is a primary cell group and the second cell group is a secondary cell group, wherein the method further comprises: performing the first random access procedure as part of at least one of: performing a secondary cell addition to add the second cell group as the secondary cell group, or performing a handover of the first cell group to the secondary cell group and a handover of the second cell group to the primary cell group.

31. The method of claim 25, wherein: The method further includes communicating with a primary cell group, wherein the first cell group and the second cell group are secondary cell groups, and wherein the method further includes performing the first random access procedure as part of performing a secondary cell addition to add the second cell group as an additional secondary cell group.

32. The method of claim 25, wherein: The method also includes: communicating with a primary cell group, wherein the first cell group and the second cell group are secondary cell groups, and wherein the method also includes: performing the first random access procedure as part of activating the second cell group as a single active secondary cell group, and further includes: deactivating the first cell group as the single active secondary cell group.

33. The method according to claim 32, wherein The method further includes receiving, from the primary cell group, the first indication for activating the second cell group as the single active secondary cell group.

34. The method of claim 25, wherein: The method also includes switching from the first DU function to the second DU function at least in part by broadcasting a second physical cell identifier (PCI) of the fourth cell group associated with the second DU function, the second PCI being different from a first PCI of the third cell group associated with the first DU function.

35. The method of claim 25, wherein: The method also includes switching from the first DU functionality to the second DU functionality at least in part by broadcasting a second cell global identifier associated with a first cell of the fourth cell group, the second cell global identifier being different from a first cell global identifier associated with a second cell of the third cell group.

36. The method of claim 25, wherein: The method further includes broadcasting first identifiers of cells of the third cell group and second identifiers of cells of the fourth cell group after switching from the first DU function to the second DU function.

37. The method of claim 25, wherein: The method also includes switching from the first DU functionality to the second DU functionality based at least in part on a primary node to secondary node switching of the MT functionality of the IAB node.

38. The method of claim 25, wherein: The method also includes: receiving a second indication for switching from the first DU function to the second DU function from the first IAB donor node or the second IAB donor node, wherein the method also includes: switching from the first DU function to the second DU function; and also triggering the subnode to migrate from the third cell group associated with the first DU function to the fourth cell group associated with the second DU function based at least in part on the second indication.

39. The method according to claim 38, wherein The method further includes triggering migration of the sub-node from the third cell group to the fourth cell group at least in part by triggering handover of the sub-node from the third cell group to the fourth cell group.

40. The method of claim 39, wherein The third cell group and the fourth cell group are secondary cell groups configured for the child node, and the method further includes: receiving an indication for releasing the third cell group for the child node.

41. The method of claim 38, wherein The method further includes forwarding a third indication to the child node, wherein the third indication indicates to the child node to migrate to a cell of the fourth cell group associated with the second DU function.

42. An apparatus for wireless communication, comprising: means for receiving, by a mobile terminal (MT) function, a first indication for migration from a first integrated access and backhaul (IAB) donor node provided by a first central unit (CU) and serving the apparatus via a first group of cells to a second IAB donor node provided by a second CU and serving the apparatus via a second group of cells; means for performing a first random access procedure to connect to the second group of cells associated with the second IAB donor node based at least in part on receiving the first indication; means for establishing, based on performing the first random access procedure, a second distributed unit (DU) function of providing a fourth cell group for serving the one or more sub-nodes in addition to the first distributed unit (DU) function of the apparatus providing a third cell group for serving the one or more sub-nodes; as well as The device is configured to trigger, based on establishing the second DU function, a second random access procedure for a subnode to migrate from the third cell group associated with the first DU function to the fourth cell group served by the second DU function.

43. The apparatus of claim 42, further comprising means for at least one of communicating with the first CU using a radio resource control (RRC) connection through the MT function of the IAB node, or communicating with the first CU using an F1-C connection through the first DU function.

44. The apparatus of claim 42, wherein: The first cell group is a source cell group and the second cell group is a target cell group for switching, wherein the device further includes: a unit for performing the first random access procedure as part of performing switching from the first cell group to the second cell group, and wherein the device further includes: a unit for releasing the connection with the first cell group based on performing switching from the first cell group to the second cell group.

45. The apparatus of claim 44, wherein: The apparatus further includes means for communicating with a primary cell group, wherein the first cell group and the second cell group are secondary cell groups.

46. ​​The apparatus of claim 45, wherein The apparatus further includes means for receiving, from the primary cell group, the first indication for migration from the first IAB donor node to the second IAB donor node.

47. The apparatus of claim 42, wherein: The first cell group is a primary cell group and the second cell group is a secondary cell group, wherein the apparatus further comprises: a unit for performing the first random access procedure as part of at least one of: performing a secondary cell addition to add the second cell group as the secondary cell group, or performing a handover of the first cell group to the secondary cell group and a handover of the second cell group to the primary cell group.

48. The apparatus of claim 42, wherein: The apparatus further comprises means for communicating with a primary cell group, wherein the first cell group and the second cell group are secondary cell groups, and wherein the apparatus further comprises means for performing the first random access procedure as a means for performing a secondary cell addition to add the second cell group as part of an additional secondary cell group.

49. The apparatus of claim 42, wherein: The apparatus further comprises means for communicating with a primary cell group, wherein the first cell group and the second cell group are secondary cell groups, and wherein the apparatus further comprises means for performing the first random access procedure as part of activating the second cell group as a single active secondary cell group, and further comprises means for deactivating the first cell group as the single active secondary cell group.

50. The apparatus of claim 49, wherein The apparatus further includes means for receiving, from the primary cell group, the first indication for activating the second cell group as the single active secondary cell group.

51. The apparatus of claim 42, wherein: The apparatus also includes a unit for switching from the first DU function to the second DU function at least in part by broadcasting a second physical cell identifier (PCI) of the fourth cell group associated with the second DU function, the second PCI being different from a first PCI of the third cell group associated with the first DU function.

52. The apparatus of claim 42, wherein: The apparatus also includes means for switching from the first DU functionality to the second DU functionality at least in part by broadcasting a second cell global identifier associated with a first cell of the fourth cell group, the second cell global identifier being different from a first cell global identifier associated with a second cell of the third cell group.

53. The apparatus of claim 42, wherein: The apparatus further includes means for broadcasting first identifiers of cells of the third cell group and second identifiers of cells of the fourth cell group after switching from the first DU functionality to the second DU functionality.

54. The apparatus of claim 42, wherein: The apparatus further includes means for switching from the first DU functionality to the second DU functionality based at least in part on a primary node to secondary node switching of the MT functionality of the IAB node.

55. The apparatus of claim 42, wherein The device also includes: a unit for receiving a second indication for switching from the first DU function to the second DU function from the first IAB donor node or the second IAB donor node, wherein the device also includes: a unit for switching from the first DU function to the second DU function; and a unit for triggering the subnode to migrate from the third cell group associated with the first DU function to the fourth cell group associated with the second DU function based at least in part on the second indication.

56. The apparatus of claim 55, wherein: The apparatus further includes means for triggering migration of the sub-node from the third cell group to the fourth cell group at least in part by triggering handover of the sub-node from the third cell group to the fourth cell group.

57. The apparatus of claim 56, wherein: The third cell group and the fourth cell group are secondary cell groups configured for the sub-node, and the apparatus further comprises: a unit for receiving an indication for releasing the third cell group for the sub-node.

58. The apparatus of claim 55, wherein The apparatus further includes means for forwarding a third indication to the child node, wherein the third indication indicates to the child node to migrate to a cell of the fourth cell group associated with the second DU function.

59. A computer-readable medium comprising code executable by one or more processors for wireless communication, the code comprising code for: Receiving, by a mobile terminal (MT) function of an integrated access and backhaul (IAB) node, a first indication for migration from a first IAB donor node provided by a first central unit (CU) and serving the IAB node via a first group of cells to a second IAB donor node provided by a second CU and serving the IAB node via a second group of cells; performing, by the IAB node and based at least in part on receiving the first indication, a first random access procedure to connect to the second group of cells associated with the second IAB donor node; In addition to providing a first distributed unit (DU) function of the IAB node for serving one or more sub-nodes in a third cell group, establishing, by the IAB node and based on performing the first random access procedure, a second DU function serving a fourth cell group for serving the one or more sub-nodes; as well as Based on establishing the second DU function, a second random access procedure is triggered for the subnode to migrate from the third cell group provided by the first DU function to the fourth cell group provided by the second DU function.

60. The computer-readable medium of claim 59, further comprising code for at least one of communicating with the first CU using a radio resource control (RRC) connection through the MT function of the IAB node, or communicating with the first CU using an F1-C connection through the first DU function of the IAB node.

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