Concurrent connectivity modes in integrated access and backhaul

Abstract

The first base station may establish a first connection with the IAB node and send a request to the second base station for the second base station to establish a second connection with the IAB node. The first base station may indicate to the second base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node based on the second connection being established with the IAB node. The second base station may accept or reject the indication received from the first base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Provisional Application No. 63 / 137,699, filed January 14, 2021, entitled "Modes of Simultaneous Connectivity in Integrated Access and Backhaul," and U.S. Patent Application No. 17 / 645,625, filed December 22, 2021, entitled "MODES OF SIMULTANEOUS CONNECTIVITY IN INTEGRATED ACCESS AND BACKHAUL," which are hereby expressly incorporated by reference in their entireties.

[0002] The present disclosure relates generally to communication systems, and more particularly to modes of concurrent connectivity for integrated access and backhaul (IAB) networks. [Background technology]

[0003] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. A typical wireless communication system may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies 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, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0004] These multiple access technologies have been adopted in various telecommunications standards to provide common protocols that enable different wireless devices to communicate on a city, national, regional, or even global scale. An exemplary telecommunications standard is 5G New Radio (NR). 5G NR is part of the ongoing mobile broadband evolution promulgated by the 3rd Generation Partnership Project (3GPP®) to meet new requirements related to latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)), and other requirements. 5G NR includes services related to enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Further improvements are needed in 5G NR technology. These improvements may also be applicable to other multiple access technologies and telecommunications standards utilizing these technologies. Summary of the Invention [Means for solving the problem]

[0005] 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, nor is it intended to identify key or critical elements of all aspects or to 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.

[0006] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be associated with a first base station and configured to: establish a first connection with an integrated access and backhaul (IAB) node; send a request to the second base station to establish a second connection with the IAB node; and indicate to the second base station, based on the second connection being established with the IAB node, that at least one of the first base station or the second base station should function as an IAB donor for the IAB node.

[0007] In one aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be configured to: receive, from a first base station associated with a second base station and having a first connection with the IAB node, a request for the second base station to establish a second connection with the IAB node; receive from the first base station an indication that at least one of the first base station or the second base station should function as an IAB donor for the IAB node based on the second connection being established with the IAB node; and accept or reject the indication received from the first base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node.

[0008] In one aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be associated with an IAB node and configured to establish a first connection with a first base station, establish a second connection with a second base station, and receive an indication from the first base station indicating that at least one of the first base station or the second base station should function as an IAB donor for the IAB node.

[0009] 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 the various aspects may be employed, and the description is intended to include all such aspects and their equivalents. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 illustrates an example of a wireless communication system and access network. [Figure 2A] FIG. 2 illustrates an example of a first frame, according to various aspects of the present disclosure. [Figure 2B] FIG. 1 illustrates an example of a DL channel within a subframe, in accordance with various aspects of the present disclosure. [Figure 2C] FIG. 10 illustrates an example of a second frame, according to various aspects of the present disclosure. [Figure 2D] FIG. 1 illustrates an example of an UL channel within a subframe, in accordance with various aspects of the present disclosure. [Figure 3] FIG. 1 illustrates an example of a base station and user equipment (UE) in an access network. [Figure 4] FIG. 1 illustrates an integrated access and backhaul (IAB) network. [Figure 5] FIG. 1 illustrates an IAB network and its components. [Figure 6] FIG. 1 illustrates a radio link control (RLC) channel in an IAB network. [Figure 7A] FIG. 1 is a diagram regarding control plane / user plane (CP-UP) separation. [Figure 7B] FIG. 1 is a diagram regarding control plane / user plane (CP-UP) separation. [Figure 8A]FIG. 1 is a diagram of inter-donor topological redundancy. [Figure 8B] FIG. 1 is a diagram regarding inter-donor topology redundancy. [Figure 9A] FIG. 1 illustrates a mode of dual connectivity for an IAB node. [Figure 9B] FIG. 1 illustrates a mode of dual connectivity for an IAB node. [Figure 9C] FIG. 1 illustrates a mode of dual connectivity for an IAB node. [Figure 10] 1 is a call flow illustrating communication between a first base station, a second base station, and an IAB node. [Figure 11] 4 is a flowchart of a wireless communication method of a first base station. [Figure 12] 4 is a flowchart of a wireless communication method of a first base station. [Figure 13] 10 is a flowchart of a wireless communication method of a second base station. [Figure 14] 10 is a flowchart of a wireless communication method of a second base station. [Figure 15] 1 is a flowchart of a method for wireless communication of IAB nodes. [Figure 16] 1 is a flowchart of a method for wireless communication of IAB nodes. [Figure 17] FIG. 1 illustrates an example of a hardware implementation for an exemplary device. [Figure 18] FIG. 1 illustrates an example of a hardware implementation for an exemplary device. [Figure 19] FIG. 1 illustrates an example of a hardware implementation for an exemplary device. DETAILED DESCRIPTION OF THE INVENTION

[0011] The detailed description set forth below with reference to the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0012] Several aspects of telecommunications systems are presented below with reference to various apparatus and methods. These apparatus and methods are described in the detailed description that follows and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the particular application and design constraints imposed on the overall system.

[0013] As an example, an element or any portion of an element or any combination of elements may be implemented as a "processing system" including one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems-on-chips (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gate logic, discrete hardware circuits, and other suitable hardware configured to perform various functions described throughout this disclosure. One or more processors in a processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0014] Thus, in one or more exemplary embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media. A storage medium may be any available medium that can be accessed by a computer. By way of example, and not limitation, such computer-readable media may comprise random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the above types of computer-readable media, or any other medium that can be used to store computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[0015] Although aspects and implementations are described in this application by illustrating several examples, those skilled in the art will understand that additional implementations and use cases may arise in many different configurations and scenarios. The aspects described herein may be implemented across many different platform types, devices, systems, shapes, sizes, and packaging configurations. For example, implementations and / or applications may arise with integrated chip implementations and other non-modular component-based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchasing devices, medical devices, artificial intelligence (AI)-enabled devices, etc.). Some examples may or may not be specifically targeted to a use case or application, but a wide variety of applicability of the described aspects may arise. Implementations may range from chip-level or modular components to non-modular, non-chip-level implementations, and even to aggregated, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more aspects of the described aspects. In some practical settings, devices incorporating the described aspects and features may also include additional components and features for implementing and practicing the claimed and described aspects. For example, transmitting and receiving wireless signals necessarily includes several components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders / summers, etc.). It is contemplated that the aspects described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed configurations, aggregated or non-aggregated components, end-user devices, etc., of various sizes, shapes, and configurations.

[0016] 1 illustrates an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a UE 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., 5G core (5GC)). The base station 102 may include a macrocell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macrocell includes a base station. A small cell includes a femtocell, a picocell, and a microcell.

[0017] A base station 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC 160 through a first backhaul link 132 (e.g., an S1 interface). A base station 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN)) may interface with the core network 190 through a second backhaul link 184. In addition to other functions, the base stations 102 may perform one or more of the following functions: forwarding user data, encryption and decryption of radio channels, 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 tracking, RAN information management (RIM), paging, positioning, and delivery of alert messages. The base stations 102 may communicate with each other directly or indirectly (e.g., through the EPC 160 or the core network 190) via a third backhaul link 134 (e.g., an X2 interface). The first backhaul link 132, the second backhaul link 184, and the third backhaul link 134 may be wired or wireless.

[0018] The base stations 102 may communicate wirelessly with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, a small cell 102' may have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network including both small cells and macro cells may be referred to as a heterogeneous network. A heterogeneous network may also include a Home evolved Node B (eNB) (HeNB) that may serve a restricted group called a Closed Subscriber Group (CSG). The communication link 120 between the base station 102 and the UE 104 may include uplink (UL) (also referred to as reverse link) transmissions from the UE 104 to the base station 102 and / or downlink (DL) (also referred to as forward link) transmissions from the base station 102 to the UE 104. The communication link 120 may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may be over one or more carriers. The base station 102 / UE 104 may use spectrum with a bandwidth of up to Y MHz per carrier (e.g., 5, 10, 15, 20, 100, 400 MHz, etc.) allocated in carrier aggregation with up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. The carrier allocation may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​than for UL). The component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell), and the secondary component carrier may be referred to as a secondary cell (SCell).

[0019] Several UEs 104 may communicate with each other using device-to-device (D2D) communication links 158. The D2D communication links 158 may use DL / UL WWAN spectrum. The D2D communication links 158 may 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). The D2D communication may be through various wireless D2D communication systems, such as WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0020] The wireless communication system may further include a Wi-Fi access point (AP) 150 communicating with a Wi-Fi station (STA) 152, such as in the 5 GHz unlicensed frequency spectrum, via a communication link 154. When communicating in the unlicensed frequency spectrum, the STA 152 / AP 150 may perform clear channel assessment (CCA) before communicating to determine whether a channel is available.

[0021] The small cell 102' may operate in licensed and / or unlicensed frequency spectrum. When operating in the unlicensed frequency spectrum, the small cell 102' may utilize NR and may use the same unlicensed frequency spectrum (e.g., 5 GHz, etc.) used by the Wi-Fi AP 150. A small cell 102' utilizing NR in the unlicensed frequency spectrum may enhance coverage to and / or increase capacity of the access network.

[0022] The electromagnetic spectrum is often subdivided into various classes, bands, channels, etc. based on frequency / wavelength. For 5G NR, two initial operating bands have been identified, designated by the frequency ranges FR1 (410 MHz to 7.125 GHz) and FR2 (24.25 GHz to 52.6 GHz). Frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Although portions of FR1 are above 6 GHz, FR1 is often referred to (interchangeably) as the "sub-6 GHz" band in various documents and papers. Similar nomenclature issues arise with FR2, which is often referred to (interchangeably) as the "mmWave" band in documents and papers, even though it differs from the extremely high frequency (EHF) band (30 GHz to 300 GHz) identified as the "mmWave" band by the International Telecommunications Union (ITU).

[0023] With the above aspects in mind, it should be understood that unless otherwise specified, terms such as "sub-6 GHz," when used herein, may broadly refer to frequencies that may be below 6 GHz, may be within FR1, or may include mid-band frequencies. Additionally, it should be understood that unless otherwise specified, terms such as "mm-wave," when used herein, may broadly refer to frequencies that may include mid-band frequencies, may be within FR2, or may be within the EHF band.

[0024] The base station 102, whether a small cell 102′ or a large cell (e.g., a macro base station), may include and / or be referred to as an eNB, gNodeB (gNB), or another type of base station. Some base stations, such as gNBs, communicate with the UE 104 and may operate in conventional sub-6 GHz spectrum, mmWave frequencies, and / or quasi-mmWave frequencies. When a gNB operates in mmWave frequencies or quasi-mmWave frequencies, the gNB may be referred to as a mmWave base station. The mmWave base station 180 may use beamforming 182 with the UE 104 to compensate for path loss and short distances. The base station 180 and the UE 104 may each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays, to facilitate beamforming.

[0025] The base station 180 may transmit beamformed signals to the UE 104 in one or more transmit directions 182′. The UE 104 may receive beamformed signals from the base station 180 in one or more receive directions 182″. The UE 104 may also transmit beamformed signals to the base station 180 in one or more transmit directions. The base station 180 may receive beamformed signals from the UE 104 in one or more receive directions. The base station 180 / UE 104 may perform beam training to determine the best receive direction and transmit direction for each of the base station 180 / UE 104. The transmit direction and receive direction for the base station 180 may or may not be the same. The transmit direction and receive direction for the UE 104 may or may not be the same.

[0026] The EPC 160 may 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 may be in communication with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. Generally, the MME 162 handles bearer and connection management. All user Internet Protocol (IP) packets are forwarded through the serving gateway 166, which is itself connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation and other functions. The PDN gateway 172 and the BM-SC 170 are connected to an IP service 176. The IP services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), PS streaming services, and / or other IP services. The BM-SC 170 may provide functionality for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within the public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS gateway 168 may be used to deliver MBMS traffic to base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area that broadcasts a particular service, and may be responsible for session management (start / stop) and collecting eMBMS-related charging information.

[0027] The core network 190 may 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 may be in communication with a unified data management (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are forwarded through the UPF 195. The UPF 195 provides IP address allocation for the UE as well as other functions. The UPF 195 is connected to IP services 197. The IP services 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), packet-switched (PS) streaming (PSS) services, and / or other IP services.

[0028] A base station may include and / or be referred to as a gNB, Node B, eNB, access point, base transceiver station, radio base station, radio transceiver, transceiver function, basic service set (BSS), extended service set (ESS), transmit reception point (TRP), or some other suitable terminology. The base station 102 provides an access point to the EPC 160 or core network 190 for the UE 104. Examples of the UE 104 include a mobile phone, smartphone, session initiation protocol (SIP) phone, laptop, personal digital assistant (PDA), satellite radio, global positioning system, multimedia device, video device, digital audio player (e.g., MP3 player), camera, game console, tablet, smart device, wearable device, vehicle, electricity meter, gas pump, large or small cooking appliance, health management device, implant, sensor / actuator, display, or any other similar function device. Some of the UE 104 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicle, heart monitor, etc.). The UE 104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0029] Referring again to FIG. 1 , in some aspects, the first base station 102 or 180 may include an integrated access and backhaul (IAB) donor designation component 198 configured to establish a first connection with the IAB node 103, send a request to the second base station to establish a second connection with the IAB node 103, and indicate to the second base station that at least one of the first base station or the second base station should function as an IAB node for the IAB node 103 based on the second connection being established with the IAB node 103. In some aspects, the second base station 102 or 180 may include an IAB donor acceptance-rejection component 199 configured to receive, from a first base station 102 or 180 having a first connection with the IAB node 103, a request for the second base station 102 or 180 to establish a second connection with the IAB node 103, receive an indication from the first base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node 103 based on the second connection being established with the IAB node 103, and accept or reject the indication received from the first base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node 103. In some aspects, the IAB node 103 may include an IAB donor determination component 191 configured to establish a first connection with a first base station 102 or 180, establish a second connection with a second base station 102 or 180, and receive an indication from the first base station indicating that at least one of the first base station or the second base station should function as an IAB donor for the IAB node 103. While the following description may focus on 5G NR, the concepts described herein may be applicable to other similar domains, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0030] Figure 2A is a diagram 200 illustrating an example of a first subframe in a 5G NR frame structure. Figure 2B is a diagram 230 illustrating an example of a DL channel in a 5G NR subframe. Figure 2C is a diagram 250 illustrating an example of a second subframe in a 5G NR frame structure. Figure 2D is a diagram 280 illustrating an example of a UL channel in a 5G NR subframe. The 5G NR frame structure may be frequency division duplex (FDD) where, for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated to either DL or UL, or time division duplex (TDD) where, for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated to both DL and UL. In the examples given by Figures 2A and 2C, the 5G NR frame structure is assumed to be TDD, subframe 4 is configured using slot format 28 (with mostly DL), where D is DL, U is UL, and F is flexible for use between DL / UL, and subframe 3 is configured using slot format 1 (with all UL). Subframes 3 and 4 are shown using slot formats 1 and 28, respectively, but any particular subframe may be configured using any of the various available slot formats 0 through 61. Slot formats 0 and 1 are all DL and UL, respectively. The other slot formats 2 through 61 contain a mix of DL, UL, and flexible symbols. The UE is configured with the slot format (dynamically through DL control information (DCI) or semi-statically / statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI). Note that the following description also applies to a TDD 5G NR frame structure.

[0031] While Figures 2A-2D illustrate frame structures, aspects of the present disclosure may be applicable to other wireless communication techniques that may have different frame structures and / or different channels. A frame (10 ms) may be divided into 10 equal-sized subframes (1 ms). Each subframe may include one or more time slots. A subframe may also include a minislot, which may include 7, 4, or 2 symbols. Each slot may include 14 or 12 symbols depending on whether the cyclic prefix (CP) is normal or extended. With a normal CP, each slot may include 14 symbols, and with an extended CP, each slot may include 12 symbols. Symbols on the DL may be CP orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. Symbols on the UL may be CP-OFDM symbols (for high-throughput scenarios) or Discrete Fourier Transform (DFT) Spread OFDM (DFT-s-OFDM) symbols (also called Single-Carrier Frequency Division Multiple Access (SC-FDMA) symbols) (for power-limited scenarios, limited to single stream transmission). The number of slots in a subframe is based on the CP and numerology. The numerology defines the subcarrier spacing (SCS), which effectively defines the symbol length / duration, which is equal to 1 / SCS.

[0032] [Table 1]

[0033] For normal CP (14 symbols / slot), the different numerologies μ 0-4 allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For extended CP, numerology 2 allows 4 slots per subframe. Therefore, for normal CP and numerology μ, 14 symbols / slot and 2 μ There are slots / subframes. The subcarrier spacing is 2 μ* may be equal to 15 kHz, where μ is a numerology between 0 and 4. Thus, numerology μ=0 has a subcarrier spacing of 15 kHz, and numerology μ=4 has a subcarrier spacing of 240 kHz. The symbol length / duration is inversely proportional to the subcarrier spacing. Figures 2A-2D provide an example of a normal CP with 14 symbols per slot and a numerology μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within a set of frames, there may be one or more different bandwidth portions (BWPs) (see Figure 2B) that are frequency-division multiplexed. Each BWP may have a specific numerology and CP (normal or extended).

[0034] A resource grid can be used to represent the frame structure. Each time slot contains a resource block (RB) (also called a physical RB (PRB)) that spans 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (RE). The number of bits carried by each RE depends on the modulation scheme.

[0035] As shown in Figure 2A, some of the REs carry reference (pilot) signals (RSs) for the UE. The RSs may include demodulation RSs (DM-RSs) (denoted as R for one specific configuration, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RSs) for channel estimation at the UE. The RSs may also include beam measurement RSs (BRSs), beam improvement RSs (BRRSs), and phase tracking RSs (PT-RSs).

[0036] Figure 2B shows an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) (e.g., 1, 2, 4, 8, or 16 CCEs), where each CCE includes six RE groups (REGs), and each REG includes 12 consecutive REs within an OFDM symbol of an RB. The PDCCHs within one BWP may be referred to as a control resource set (CORESET). A UE is configured to monitor PDCCH candidates within a PDCCH search space (e.g., a common search space, a UE-specific search space) during PDCCH monitoring opportunities in the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be at higher and / or lower frequencies across the channel bandwidth. A primary synchronization signal (PSS) may be within symbol 2 of a specific subframe of the frame. The PSS is used by the UE 104 to determine subframe / symbol timing and physical layer identity. The secondary synchronization signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the DM-RS mentioned above. The physical broadcast channel (PBCH), which carries the master information block (MIB), may be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block (also called an SS block (SSB)). The MIB provides the number of RBs in the system bandwidth and the system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted over the PBCH, such as system information blocks (SIBs), and paging messages.

[0037] As shown in FIG. 2C, some of the REs carry DM-RS (denoted as R for one particular configuration, although other DM-RS configurations are possible) for channel estimation at the base station. The UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH). The PUSCH DM-RS may be transmitted in the first one or two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether a short or long PUCCH is transmitted and the particular PUCCH format used. The UE may transmit a sounding reference signal (SRS). The SRS may be transmitted in the last symbol of a subframe. The SRS may have a comb structure, and the UE may transmit the SRS in one of the combs. The SRS may be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0038] 2D shows an example of various UL channels within a subframe of a frame. In one configuration, the PUCCH may be located as shown. The PUCCH carries uplink control information (UCI) such as scheduling requests, channel quality indicators (CQIs), precoding matrix indicators (PMIs), rank indicators (RIs), and hybrid automatic repeat request (HARQ) acknowledgment (ACK) (HARQ-ACK) information (ACK / negative ACK (NACK)) feedback. The PUSCH carries data and may be further used to carry buffer status reports (BSRs), power headroom reports (PHRs), and / or UCI.

[0039] 3 is a block diagram of a first wireless device 310 communicating with a second wireless device 350 in an access network. In some examples, the first wireless communication device may be a base station and the second wireless communication device may be a UE. In other examples, the first wireless device 310 may be a base station and the second wireless device 350 may be a second base station. In some examples, the first wireless communication device 310 may be a base station and the second wireless communication device may be an IAB node. In some examples, the first wireless communication device 310 may be an IAB node and the second wireless communication device 350 may be a UE.

[0040] In the DL, IP packets from the EPC 160 may be provided to the controller / processor 375. The controller / processor 375 implements Layer 3 and Layer 2 functions. Layer 3 includes the Radio Resource Control (RRC) layer, and Layer 2 includes the Service Data Adaptation Protocol (SDAP) layer, the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer, and the Medium Access Control (MAC) layer. The controller / processor 375 provides RRC layer functions related to broadcasting of system information (e.g., MIBs, SIBs), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-Radio Access Technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions related to header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions related to transfer of upper layer packet data units (PDUs), error correction via ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions related to mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0041] The transmit (TX) processor 316 and receive (RX) processor 370 implement Layer 1 functions related to various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection on transport channels, forward error correction (FEC) coding / decoding of transport channels, interleaving, rate matching, mapping onto physical channels, modulation / demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be separated into parallel streams. Each stream may then be mapped to OFDM subcarriers, multiplexed with reference signals (e.g., pilots) in the time and / or frequency domains, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is spatially precoded to generate multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme and for spatial processing. The channel estimates may be derived from a reference signal and / or channel condition feedback transmitted by the second wireless device 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter TX 318. Each transmitter TX 318 may modulate an RF carrier with the respective spatial stream for transmission.

[0042] In the second wireless device 350, each receiver RX 354 receives a signal through its respective antenna 352. Each receiver RX 354 recovers information modulated onto an RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement Layer 1 functionality related to various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the second wireless device 350. If multiple spatial streams are destined for the second wireless device 350, the spatial streams may be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then converts the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation point transmitted by the first wireless device 310. These soft decisions may be based on channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted by the first wireless device 310 on the physical channel. The data and control signals are then provided to a controller / processor 359, which performs Layer 3 and Layer 2 functions.

[0043] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 performs demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0044] Similar to the functionality described with respect to DL transmission by the first wireless device 310, the controller / processor 359 provides RRC layer functions related to system information (e.g., MIBs, SIBs) collection, RRC connection, and measurement reporting; PDCP layer functions related to header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions related to transfer of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions related to mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0045] Channel estimates derived by the channel estimator 358 from a reference signal or feedback transmitted by the first wireless device 310 may be used by the TX processor 368 to select an appropriate coding and modulation scheme as well as to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters TX 354. Each transmitter TX 354 may modulate an RF carrier with a respective spatial stream for transmission.

[0046] UE transmissions are processed at the first wireless device 310 in a manner similar to that described with respect to the receiver functions at the second wireless device 350. Each receiver RX 318 receives signals through its respective antenna 320. Each receiver RX 318 recovers information modulated onto an RF carrier and provides the information to the RX processor 370.

[0047] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 performs demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the second wireless device 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0048] At least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform aspects associated with the IAB donor designation component 198 of FIG.

[0049] At least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform aspects associated with the IAB donor acceptance-rejection component 199 of FIG.

[0050] At least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform aspects associated with the IAB donor determination component 191 of FIG.

[0051] Wireless communication systems may be configured to provide various telecommunication services (e.g., telephony, video, data, messaging, broadcast, etc.) based on CDMA systems, TDMA systems, FDMA systems, OFDMA systems, SC-FDMA systems, TD-SCDMA systems, etc., which share available system resources and support communication with multiple users. Common protocols that facilitate communication with wireless devices are often adopted in various telecommunication standards. For example, communication methods related to eMBB, mMTC, and URLLC may be incorporated into the 5G NR telecommunication standard, and other aspects may be incorporated into the 4G LTE standard. Because mobile broadband technology is part of a continuous evolution, further improvements in mobile broadband will continue to be useful to continue the advancement of such technology.

[0052] Figure 4 illustrates an IAB network 400. The IAB network provides access network functionality between access nodes (ANs) and other ANs / UEs, and backhaul network functionality between ANs. The ANs include IAB donors with wireline connections to the core network 490 and IAB nodes that operate wirelessly and relay traffic to and from the IAB donors through one or more AN hops. The IAB ANs share resources between access and backhaul; that is, resources used for access communications between the ANs and ANs / UEs are also used for backhaul communications between ANs.

[0053] The IAB network 400 may include an anchor node, sometimes referred to herein as an “IAB donor” 410, and an access node, sometimes referred to herein as an “IAB node” 420. The IAB donor 410 may be a base station, such as a gNB or eNB, and may perform functions for controlling the IAB network 400. The IAB node 420 may comprise an L2 relay node, or the like. Together, the IAB donor 410 and the IAB node 420 share resources to provide an access network and a backhaul network to the core network 490. For example, resources may be shared between access links and backhaul links within the IAB network.

[0054] The UE 430 interfaces with the IAB node 420 or the IAB donor 410 through an access link 470. The IAB nodes 420 communicate with each other and with the IAB donor 410 through a backhaul link 460. The IAB donor 410 is connected to the core network 490 via a wireline backhaul link 450. The UE 430 communicates with the core network 490 by relaying messages to the IAB network 400 through their respective access links 470, which may then relay messages to the IAB donor 410 through the backhaul link 460 for communication to the core network 490 through the wireline backhaul link 450. Similarly, the core network 490 may communicate with the UE 430 by sending messages to the IAB donor 410 through the wireline backhaul link 450. The IAB donor 410 sends the message through the IAB network 400 via a backhaul link 460 to an IAB node 420 connected to the UE 430, and the IAB node 420 sends the message to the UE 430 via an access link 470.

[0055] For example, each IAB node, including the IAB donor 410 and each IAB node 420, may use a PCI value. The PCI value may serve as an identifier for the IAB donor 410 or IAB node 420. The PCI value may be used to determine a scrambling sequence that may be applied to a physical signal and / or channel transmitted by a particular IAB node. For example, the PSS and / or SSS transmitted by each IAB donor 410 or IAB node 420 may be scrambled using a scrambling sequence that may be based on the PCI used by the respective IAB node.

[0056] 5 is a diagram illustrating an IAB network 500 and its components. The IAB network 500 includes an IAB donor node 510 and IAB nodes 520a-520b. The IAB nodes 520a-520b, as well as the IAB donor node 510, may provide wireless access links to UEs 530a-530c.

[0057] The IAB donor node 510 may be considered the root node of the tree structure of the IAB network 500. The IAB donor node 510 may be connected to the core network 590 via a wired connection 591. The wired connection may include, for example, wireline fiber. The IAB donor node 510 may provide a connection to one or more IAB nodes 520a. Each of the IAB nodes 520a may be referred to as a child node of the IAB donor node 510. The IAB donor node 510 may also provide a connection to one or more UEs 530a, which may be referred to as child UEs of the IAB donor node 510. The IAB donor node 510 may be connected to its child IAB node 520a via a backhaul link 560 and to a child UE 530a via an access link 570. An IAB node 520a, which is a child node of the IAB node 510, may also have an IAB node 520b and / or a UE 530b as a child. For example, IAB node 520b may further connect to child nodes and / or child UEs. Figure 5 shows IAB node 520b providing an access link to each of UEs 530c.

[0058] The IAB donor node 510 may include a aggregation unit (CU) and a distribution unit (DU). The CU may provide control for the IAB nodes 520a, 520b within the IAB network 500. For example, the CU may control the IAB network 500 through configuration. The CU may perform RRC / PDCP layer functions. The IAB donor node 510 further includes a DU that may perform scheduling. For example, the DU may schedule resources for communication by the IAB donor node 510's child IAB node 520a and / or UE 530a. The DU is associated with radio link control (RLC), medium access control (MAC), and physical (PHY) layer functions.

[0059] IAB nodes 520a, 520b may include a mobile termination (MT) and a DU. The IAB nodes may be L2 relay nodes. The MT of IAB node 520a may act as a scheduled node that can be scheduled similarly to UE 530a by a DU of a parent node, e.g., IAB donor node 510. The MT of IAB node 520b may act as a scheduled node of parent node 520a. The DU may schedule child IAB node 520b and UE 530b of IAB node 520a. An IAB node can provide a connection to an IAB node, and the IAB node can provide another connection to another IAB node. The pattern of parent IAB node with DUs scheduling child IAB nodes / child UEs can continue for more connections.

[0060] FIG. 6 is a diagram 600 illustrating RLC channels in an IAB network. As discussed above, the IAB network provides both access and backhaul network functions. The IAB network includes an IAB donor with a CU 602 and a DU 604. To provide access network functions, the IAB nodes 606a, 606b, and 606c may communicate with other UEs 608a and 608b and / or MTs of other IAB ANs through access RLC channels. Thus, the IAB nodes 606a, 606b, and 606c operate as access IAB nodes for their child nodes or UEs. To provide backhaul network functions, the IAB nodes 606a, 606b, and 606c may route traffic to other IAB nodes (e.g., 606a, 606b, and 606c) through backhaul RLC channels (BH RLC CHs). Thus, IAB nodes 606a, 606b, and 606c may act as intermediate IAB nodes when backhauling traffic for other IAB nodes. The access RLC channel includes UE-to-DU / DU-to-UE, which carries PDCP for RRC or data radio bearer (DRB), and MT-to-DU / DU-to-MT, which carries PDCP for RRC (or DRB). The BH RLC CH includes MT-to-DU / DU-to-MT, which carries Backhaul Adaptation Protocol (BAP) messages for backhauling access traffic.

[0061] 7A-7B include diagrams 700-750 illustrating control plane / user plane (CP-IP) separation based on dual connectivity. In diagram 700, the F1 control plane (F1-C) interface between IAB Node 2 702a and IAB donor CU 708a may be based on an access link via a primary RAN node (e.g., a non-donor node). The primary RAN node may be referred to as a Master NG-RAN (M-NG-RAN) node 710. The F1 user plane (F1-U) interface between IAB Node 2 702a and IAB donor CU 708a may be based on a backhaul link via IAB Node 1 704a and IAB donor DU 706a. More specifically, IAB Node 2 702a may be dual-connected based on connections to the M-NG-RAN 710 and IAB Node 1 704a. Because IAB nodes may have UE capabilities, IAB node 2 702a may be RRC connected to both the M-NG-RAN node 710 and the IAB donor CU 708a. Dual connectivity may be based on a single physical link or multiple physical links. For example, IAB node 2 702a may communicate to a second node (e.g., IAB donor CU 708a) via a master node (e.g., M-NG-RAN 710) without a physical link between IAB node 2 and the master node, or IAB node 2 702a may be connected to the master node and the second node based on a physical link between each of the nodes.

[0062] Different connections between nodes via the F1 interface may provide different levels of coverage robustness for the control plane (c-plane) or different levels of capacity for the user plane (u-plane). Robust coverage may be associated with sub-6 GHz frequency bands because such signals may be less susceptible to attenuation than signals based on millimeter wave (mmW) frequency bands. For example, the M-NG-RAN node 710 may be a base station serving one or more child nodes via sub-6 GHz signals, which may have robust coverage that allows the M-NG-RAN node 710 to communicate with the child nodes in a single hop. In contrast, mmW signals, which may be susceptible to attenuation, may not be used to communicate over physical distances as large as sub-6 GHz signals. Thus, for example, multiple hops may be performed between IAB node 2 702a and IAB donor CU 708a via IAB node 1 704a and IAB donor DU 706a. However, mmW may be associated with large frequency bands, which may be utilized to provide increased capacity via sub-6 GHz signals.

[0063] In a configuration, IAB node 2 702 may be connected to a first base station via sub-6 GHz signaling and to a second base station via mmW signaling. For example, F1 signaling may be split at IAB node 2 702a so that the access link is usable for the c-plane and the backhaul link is usable for the u-plane. The distance between a base station (e.g., M-NG-RAN 710) and an IAB donor (e.g., IAB donor CU 708a) may be such that the IAB donor is a base station configured to support IAB functionality. If the M-NG-RAN node 710 is a base station that does not support / assert IAB functionality, the F1-U connection to the DU of IAB node 2 702a may utilize multiple hops on the backhaul link via mmW signaling, while the F1-C connection may utilize the RRC connection of the MT of IAB node 2 702a to transmit the container to the IAB donor CU 708a via the M-NG-RAN 710.

[0064] In diagram 750, the F1-C interface between IAB node 2 702b and IAB donor CU 708b may be based on an access link via a secondary NG-RAN (S-NG-RAN) node 712 (e.g., a non-donor node), and the F1-U interface between IAB node 2 702b and IAB donor CU 708b may be based on a backhaul link via IAB node 1 704b and IAB donor DU 706b. For example, IAB donor CU 708b may be a master node that may receive containers over the F1-C interface in a single hop via the S-NG-RAN node 712. The single hop of the F1-C interface may provide robust coverage, while the F1-U interface may be associated with multiple hops but may provide increased capacity.

[0065] Thus, in diagram 700, the F1-C interface may be based on the use of an access link to communicate with the second node, and the F1-U interface may be based on the use of a backhaul link to communicate with the second node, in which case the master node (e.g., M-NG-RAN 710) may be a non-donor node and the second node (e.g., IAB donor CU 708a) may be a donor node. Alternatively, in diagram 750, the F1-C interface may be based on the use of a backhaul link to communicate with the master node, and the F1-U interface may be based on the use of an access link to communicate with the master node, in which case the second node (e.g., S-NG-RAN 712) may be a non-donor node and the master node (e.g., IAB donor CU 708b) may be a donor node. In either case, the access link and / or backhaul link may be based on either mmW signaling and / or sub-6 GHz signaling. Furthermore, the access link and / or backhaul link may be based on a single-hop or multi-hop configuration. The difference between utilizing the access link and the backhaul link for communication is that the access link traffic may be carried on an access RLC channel, and the backhaul link traffic may be carried on a BAP via a backhaul RLC channel. In Figures 700-750, the F1-C connection is routed via the RRC of the access link, and the F1-U connection is routed via the backhaul BAP / IP layer.

[0066] 8A-8B include diagrams 800-850 illustrating inter-donor topology redundancy. When an IAB node (e.g., IAB3 node 802-803) is dual-connected to two donor nodes (e.g., Donor1-DU 806 and Donor2-DU 812), the backhaul link may include a first leg and a second leg. The first leg may include the IAB3 nodes 802-803 with IAB3-MT 803 and IAB3-DU 802, the IAB1 node 804 with IAB1-MT and IAB1-DU, Donor1-DU 806, and Donor1-CU 808. The second leg may include the IAB3 nodes 802-803, the IAB2 node 810 with IAB2-MT and IAB2-DU, Donor2-DU 812, and Donor1-CU 808.

[0067] Thus, backhaul information may be transmitted over two paths to provide robustness and load balancing. Inter-donor topology redundancy may be based on IAB-DU 802 having an F1 interface with a single donor CU. IAB3-DU 802 may be connected to Donor 1-CU 808 via an F1 interface, which may be split into an F1-C interface and an F1-U interface. Thus, IAB3-DU 802 may have an F1 interface that includes two parts. For robustness, the F1-C portion of the F1 interface between IAB3-DU 802 and Donor 1-CU 808 may utilize a different path to transmit F1-C traffic between IAB3-DU 802 and Donor 1-CU 808 in a more reliable manner. For load balancing, the F1-U portion of the F1 interface may be utilized to reduce traffic transmitted over the first topology associated with Donor 1-CU 808 by transmitting some of the traffic over the second topology associated with Donor 2-CU 814. For example, if the IAB3 nodes 802-803 serving the first UE 816a and the second UE 818a initially overload the first topology by sending all of the traffic to the first UE 816a and the second UE 818a via the first topology, the IAB3 nodes 802-803 may perform load balancing by sending additional traffic to the second UE 818a via the second topology and continuing to send traffic to the first UE 816a via the first topology.

[0068] In diagram 800, IAB3 nodes 802-803 may be access IAB nodes serving a first UE 816a and a second UE 818a. In diagram 850, IAB3 nodes 802-803 may be one or more hops away from a first UE 816b and a second UE 818b, which may be served by an IAB4 node 820. The IAB4 node 820 may forward traffic for the first UE 816b and the second UE 818b to the IAB3 nodes 802-803 to perform load balancing based on topology redundancy. Thus, the first and second legs of the backhaul link may be expanded to further include the IAB4 node 820. Thus, a first configuration associated with diagram 800 may include IAB3 nodes 802-803 that are dual-connected with two donor nodes, and a second configuration associated with diagram 850 may include IAB3 nodes 802-803 that are parent / ancestor nodes of IAB4 node 820 and are also dual-connected with two donor nodes. Both CP-UP isolation and topology redundancy may be performed for dual-connected IAB nodes and ancestor / descendant IAB nodes of the dual-connected IAB nodes.

[0069] In one example, the F1-C interface may include multiple hops, and the F1-U interface may include a single hop. However, neither the access link nor the backhaul link is limited to a single-hop or multi-hop configuration. To perform CP-UP separation over multiple topologies, IAB3-MT 803 can connect to Donor 1-CU 808 over an access link of a first topology (e.g., communicating F1-C traffic using the access RLC channel of the link between IAB3-MT 803 and IAB1 804), and IAB3-MT 803 can connect to Donor 2-CU 814 over a backhaul link of a second topology (e.g., communicating F1-U traffic using the backhaul RLC channel of the link between IAB3-MT 803 and IAB2 810). Given that both CP-UP isolation (e.g., as described with respect to Figures 700-750) and topology redundancy techniques (e.g., as described with respect to Figures 800-850) may be implemented after IAB3 nodes 802-803 are dual-connected, IAB3 nodes 802-803 may have to decide which technique to use.

[0070] 9A-9C illustrate exemplary modes of multi-connectivity including dual connections 900, 920, and 940 for an IAB node 902. For example, CP-UP separation via a first mode of dual connection 900 for an IAB node 902 may be performed based on a first base station 904 (e.g., a primary node) being a non-donor node and a donor CU2 914 (e.g., a secondary node) being a donor node. CP-UP separation via a secondary mode of dual connection 920 for an IAB node 902 may be performed based on a donor CU1 912 (e.g., a primary node) being a donor node and a second base station 906 (e.g., a secondary node) being a non-donor node. Topology redundancy via a third mode of dual connection 940 for an IAB node 902 may be performed based on a donor CU1 912 (e.g., a primary node) and a donor CU2 914 (e.g., a secondary node), both being donor nodes.

[0071] If a base station is not configured to support IAB functionality, the base station cannot be a donor node. If a base station is configured to support IAB functionality but determines to serve the MT of the IAB node 902 as a base station that does not assert IAB functionality for the IAB node 902, the base station similarly cannot be a donor node. However, if the base station asserts IAB functionality for the IAB node 902, the base station can become a donor node. In some configurations, the same base station can be a donor node for a first IAB node and a non-donor node for a second IAB node (e.g., the base station can terminate the RRC connection with the MT of the second IAB node). The backhaul link including the BH RLC CH can be based on a single hop or multiple hops.

[0072] Because either donor CU1 912, donor CU2 914, or both may be base stations that may assert donor functionality for the IAB node 902, CP-UP separation and topology redundancy may need to be coordinated between the nodes. The IAB node 902 may initially connect to one of the second base station 906 or donor CU1 912 (e.g., via parent DU1 908), or may connect to the first base station 904 or donor CU2 914 (e.g., via parent DU2 910) at a first time, and the IAB node 902 may subsequently connect to the other of the second base station 906 / donor CU1 912 or first base station 904 / donor CU2 914 at a second time to provide dual connectivity. The first node initially connected to the IAB node 902 may determine whether CP-UP separation or topology redundancy should be performed for the IAB node 902.

[0073] The first base station 904 may decide whether to become a donor node (e.g., donor CU1 912) for the IAB node 902 or to operate as a non-donor node (e.g., the first base station 904). When the IAB node 902 connects to the second base station 906 / donor CU2 914 via the second link, the first base station 904 may indicate to the second base station 906 / donor CU2 914 whether the first base station 904 intends to operate as a donor node (e.g., donor CU1 912) or as a non-donor node (e.g., the first base station 904). If the initial base station connecting to the IAB node 902 determines not to perform the decision-making procedure, the originally connected base station may hand over the decision to another base station (e.g., the second base station 906) that can accept the decision-making task. Such a procedure may occur when both the first base station 904 and the second base station 906 are capable of providing donor functionality for the IAB node 902 .

[0074] The first base station 904 / donor CU1 912 may establish a first signaling connection with the IAB node 902 and may thereafter send a request to the second base station 906 / donor CU2 914 to establish a second signaling connection between the IAB node 902 and the second base station 906 / donor CU2 914, where the second signaling connection may be maintained concurrently with the first signaling connection. The second base station 906 / donor CU2 914 may receive a request to establish a second signaling connection between the IAB node 902 and the second base station 906 / donor CU2 914 from the first base station 904 / donor CU1 912, which established the first signaling connection with the IAB node 902. Based on the simultaneous connection, the IAB node 902 may be dual-connected such that the first base station 904 / donor CU1 912 and the second base station 906 / donor CU2 914 may coordinate with each other to determine whether the first base station 904 / donor CU1 912 and / or the second base station 906 / donor CU2 914 assert donor functionality for the IAB node 902.

[0075] The first signaling connection may be an RRC connection or an F1-C connection. The second signaling connection may also be an RRC connection or an F1-C connection. More specifically, the IAB node 902 may include a MT for the RRC connection and a DU for the F1-C connection. When the IAB node 902 has an F1-C connection with both the first base station 904 and the second base station 906, multiple logical IAB-DUs may be provided in the IAB node 902 associated with different CUs of the first base station 904 and the second base station 906. When one of the first base station 904 or the second base station 906 configures a BH RLC CH in the IAB-MT of the IAB node 902, the first base station 904 or the second base station 906 may be inferred as an IAB donor for the IAB node 902.

[0076] The simultaneous connection of the first base station 904 / donor CU1 912 and the second base station 906 / donor CU2 914 with the IAB node 902 may be based on NR dual connectivity (NR-DC), multiple radio dual connectivity (MR-DC), dual active protocol stack (DAPS), or multi-MT connectivity. DAPS may be utilized when a UE is handed over from the first base station 904 to another base station to reduce interference time for the UE. However, the UE may still continue to receive from both the first base station and another base station (e.g., a source base station and a target base station) simultaneously, such that a master node and a secondary node cannot be designated. Multi-MT connectivity is available when the IAB node 902 includes two MTs, which may allow two UEs to independently connect to different locations, as opposed to an IAB node including one MT. In an aspect, a second signaling connection with the IAB node 902 may be initiated by the IAB node 902, in which case the first base station 904 and / or the second base station 906 may function as an IAB donor (e.g., donor CU1 912 and / or donor CU2 914). That is, the first base station 904 and the second base station 906 may support IAB functionality and may or may not become an IAB donor depending on whether the first base station 904 or the second base station 906 asserts IAB donor functionality toward the IAB node 902. As described herein, such a decision may be coordinated between the first base station 904 and the second base station 906.

[0077] In a first aspect, asserting IAB donor capability may include terminating F1 connectivity with the IAB node 902. In a second aspect, asserting IAB donor capability may include establishing a BH RLC CH at the IAB node 902 because the BH RLC CH may be used for the IAB node 902 to relay traffic between a child node and a parent node (e.g., parent DU1 908 and parent DU2 910). The IAB donor may configure a BH RLC CH for the parent node in the MT of the IAB node (e.g., based on RRC connectivity between the IAB-MT and the IAB donor CU). The IAB donor may also configure a BH RLC CH for the child node in the DU of the IAB node or in the IAB donor DU (e.g., based on F1-C connectivity between the IAB-DU / IAB donor DU and the IAB donor CU). In a third aspect, asserting IAB donor capability may include providing a BAP configuration to the IAB node 902. When the IAB node 902 is dual-connected, quality of service (QoS) support as well as routing functionality for communicating with the donor node over the connection may be associated with the BAP layer. The IAB donor may configure the BAP layer. In a fourth aspect, asserting IAB donor functionality may include providing a base station DU cell resource configuration to the IAB node 902. Because transmissions in the DU may cause self-interference in the MT, the CU may provide the cell resource configuration for the IAB node 902 based on the half-duplex (HD) constraints of the IAB node 902. In a fifth aspect, asserting IAB donor functionality may include providing an IP configuration to the IAB node 902, which may include one or more IP addresses or IP prefixes. For the IAB node 902 to be reachable from the IP network, the IP address may be selected so that the IP network can receive the IP address when the IAB node 902 connects with the CU through the first donor DU. When the IAB node 902 communicates with the CU through the second DU, the IP network may receive a different IP address.

[0078] To coordinate assertion of IAB donor capabilities, the first base station 904 / donor CU1 912 may indicate to the second base station 906 / donor CU2 914 whether the second base station 906 / donor CU2 914 should assert IAB donor capabilities for the IAB node 902. Additionally or alternatively, the first base station 904 / donor CU1 912 may indicate to the second base station 906 / donor CU2 914 whether the first base station 904 / donor CU1 912 should assert IAB donor capabilities for the IAB node 902. In some configurations, both the first base station 904 and the second base station 906 may be IAB donors that assert IAB capabilities. For example, a first base station 904 / donor CU1 912 may indicate to a second base station 906 / donor CU2 914 that the first base station 904 and the second base station 906 should both assert IAB donor capabilities toward the IAB node 902. In an aspect, the first base station 904 / donor CU1 912 may indicate to a second base station 906 / donor CU2 914 that the first base station and / or the second base station should assert a subset of IAB donor capabilities toward the IAB node 902. When the IAB node 902 is connected to two donors, the first donor (e.g., donor CU1 912) may be for HD constraints and the second donor (e.g., donor CU2 914) may be for QoS support. Thus, a first IAB node may provide resource configuration for all IAB nodes in the topology, while a second IAB node may configure all BH RLC CHs and also provide the corresponding BAP configuration.

[0079] The first base station 904 / donor CU1 912 may indicate to the second base station 906 / donor CU2 914 that it may obtain c-plane connectivity or u-plane connectivity with the IAB node 902 via the first base station 904 / donor CU1 912 to the second base station 906 / donor CU2 914 to assert IAB donor functionality to the IAB node 902. In a further configuration, the first base station 904 / donor CU1 912 may indicate to the second base station 906 / donor CU2 914 that the first base station 904 / donor CU1 912 should obtain c-plane connectivity or u-plane connectivity with the IAB node 902 via the second base station 906 / donor CU2 914 to the first base station 904 / donor CU1 912 to assert IAB donor capabilities to the IAB node 902. The second base station 906 / donor CU2 914 can accept or reject the first base station 904 / donor CU1 912's request.

[0080] 10 is a communication flow diagram 1000 illustrating communication between a first base station 1002, a second base station 1004, and an IAB node 1006. At 1008, the first base station 1002 may establish a first connection with the IAB node 1006. The first connection established at 1008 may correspond to a first RRC connection or a first F1-C interface. At 1010, the first base station 1002 may send a request to the second base station 1004 for the second base station 1004 to establish a second connection with the IAB node 1006. At 1012, the second base station 1004 may establish a second connection with the IAB node 1006 based on the request received from the first base station 1002 at 1010. The second connection established at 1012 may correspond to a second RRC connection or a second F1-C interface. At 1014 , the second base station 1004 may send an acknowledgment / acceptance to the first base station 1002 indicating that the second base station 1004 has established a second connection with the IAB node 1006 .

[0081] At 1016, the first base station 1002 may transmit an IAB donor status indication to the second base station 1004 indicating whether the first base station 1002 and / or the second base station 1004 should function as an IAB donor for the IAB node 1006. In an aspect, the indication transmitted at 1016 may indicate whether the second base station 1004 should establish a c-plane connection or a u-plane connection with the IAB node 1006. At 1018, the second base station 1004 can accept or reject the IAB donor status indication received from the first base station 1002 at 1016.

[0082] At 1020, the first base station 1002 may send an IAB donor indication to the IAB node 1006 indicating whether the first base station 1002 and / or the second base station 1004 should function as an IAB donor for the IAB node 1006 based on the acceptance or rejection received from the second base station 1004 at 1018. At 1022a, the second base station 1004 may assert IAB donor functionality for the IAB node 1006 if the second base station 1004 should function as an IAB donor for the IAB node 1006. Additionally or alternatively, at 1022b, the first base station 1002 may assert IAB donor functionality for the IAB node 1006 if the first base station 1002 should function as an IAB donor for the IAB node 1006. At 1024, to function as an IAB donor / assert IAB donor functionality for the IAB node 1006, the first base station 1002 and / or the second base station 1004 may establish a backhaul RLC channel with the IAB node (e.g., based on 1024(1)), send a BAP configuration to the IAB node (e.g., based on 1024(2)), send a cell resource configuration for the DU to the IAB node (e.g., based on 1024(3)), send an IP configuration to the IAB node (e.g., based on 1024(4)), and / or terminate F1 connectivity with the IAB node (e.g., based on 1024(5)).

[0083] 11 is a flowchart 1100 of a method of wireless communication. The method may be performed by a base station, e.g., the first base station 1002, which may include the memory 376 and may be the entire first base station 1002 or a component of the first base station 1002, such as the TX processor 316, the RX processor 370, and / or the controller / processor 375. The method may enable the base station to coordinate donor functionality for IAB nodes with a second base station.

[0084] A first base station may establish a first connection with an IAB node at 1102. For example, with reference to Figure 10, a first base station 1002 may establish a first connection with an IAB node 1006 at 1008. The first connection may be established by, for example, an establishing component 1740 of the apparatus 1702.

[0085] At 1104, the first base station may send a request to the second base station for the second base station to establish a second connection with the IAB node. For example, referring to FIG. 10, the first base station 1002 may send a request to the second base station 1004 to establish a second connection with the IAB node 1006 at 1010. The first connection (e.g., established at 1008) may be based on at least one of a first RRC connection or a first F1-C interface, and the second connection (e.g., established at 1012) may be based on at least one of a second RRC connection or a second F1-C interface. The first connection (e.g., established at 1008) and the second connection (e.g., established at 1012) may provide DC to the IAB node 1006. The DC may be associated with at least one of NR-DC, MR-DC, DAPS, or multi-MT connectivity. The request may be transmitted, for example, by the transmitting component 1734 of the device 1702 .

[0086] At 1106, the first base station may indicate to the second base station that at least one of the first base station or the second base station should function as an IAB donor to the IAB node based on the second connection being established with the IAB node. For example, with reference to FIG. 10 , the first base station 1002 may receive at 1014 an acknowledgment of the second connection established at 1012 by the second base station 1004 and may transmit at 1016 an IAB donor status indication for the first base station 1002 and / or the second base station 1004 to the second base station 1004 based on the received acknowledgment. The second connection may be indicated, for example, by the indication component 1742 of the apparatus 1702.

[0087] 12 is a flowchart 1200 of a method of wireless communication. The method may be performed by a base station, e.g., the first base station 1002, which may include the memory 376 and may be the entire first base station 1002 or a component of the first base station 1002, such as the TX processor 316, the RX processor 370, and / or the controller / processor 375. The method may enable the base station to coordinate donor functionality for IAB nodes with a second base station.

[0088] A first base station may establish a first connection with an IAB node at 1202. For example, with reference to Figure 10, a first base station 1002 may establish a first connection with an IAB node 1006 at 1008. The first connection may be established by, for example, an establishing component 1740 of the apparatus 1702.

[0089] At 1204, the first base station may send a request to the second base station for the second base station to establish a second connection with the IAB node. For example, referring to FIG. 10, the first base station 1002 may send a request to the second base station 1004 to establish a second connection with the IAB node 1006 at 1010. The first connection (e.g., established at 1008) may be based on at least one of a first RRC connection or a first F1-C interface, and the second connection (e.g., established at 1012) may be based on at least one of a second RRC connection or a second F1-C interface. The first connection (e.g., established at 1008) and the second connection (e.g., established at 1012) may provide DC to the IAB node 1006. The DC may be associated with at least one of NR-DC, MR-DC, DAPS, or multi-MT connectivity. The request may be transmitted, for example, by the transmitting component 1734 of the device 1702 .

[0090] At 1206, the first base station may explicitly or implicitly indicate to the second base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node based on the second connection being connected with the IAB node. For example, referring to FIG. 10 , the first base station 1002 may receive at 1014 an acknowledgment of the second connection established at 1012 by the second base station 1004 and may transmit at 1016 an IAB donor status indication for the first base station 1002 and / or the second base station 1004 to the second base station 1004 based on the received acknowledgment. The second connection may be indicated, for example, by the indication component 1742 of the apparatus 1702.

[0091] When a first base station (e.g., a master node) determines that a second base station (e.g., a secondary node) is an F1 termination donor node for the IAB node, the first base station may explicitly signal a corresponding request / instruction to the second base station. For example, the first base station may request the second base station to locate an IP address and establish an F1 connection with the IAB node. Alternatively, when the first base station determines to be an F1 termination donor node for the IAB node, the first base station may not explicitly signal such information to the second base station. Instead, the first base station may send an instruction to the second base station to offload traffic to the second base station (e.g., based on topology redundancy) or to use the communication path between the IAB node and the second base station as an access link (e.g., based on CP-UP separation), in which case the instruction may implicitly indicate to the second base station that the first base station has determined to be an F1 termination donor node for the IAB node.

[0092] The first base station 1002 may indicate to the second base station 1004 at 1016 that the second base station 1004 should function as an IAB donor for the IAB node 1006. In some configurations, the first base station 1002 may indicate to the second base station 1004 that the second base station 1004 should provide a subset of IAB donor functionality to the IAB node 1006. The indication to the second base station 1004 at 1016 may further indicate that the second base station 1004 should establish at least one of a c-plane connection or a u-plane connection with the IAB node 1006 via the first base station 1002 to function as an IAB donor for the IAB node 1006, where the c-plane connection is established in connection with a CP-UP separation procedure and the u-plane connection is established in connection with a topology redundancy procedure. Alternatively, the first base station 1002 may indicate to the second base station 1004 at 1016 that the first base station 1002 should function as an IAB donor for the IAB node 1006. The indication to the second base station 1004 at 1016 may further indicate that the first base station 1002 should establish at least one of a c-plane connection or a u-plane connection with the IAB node 1006 via the second base station 1004 to function as an IAB donor for the IAB node 1006. In a further aspect, the first base station 1002 may indicate to the second base station 1004 at 1016 that the first base station 1002 and the second base station 1004 should function as IAB donors for the IAB node 1006.

[0093] At 1208, when a first base station indicates to a second base station that the first base station will function as an IAB donor for the IAB node, the first base station may indicate IAB donor capabilities to the IAB node. For example, referring to FIG. 10 , the first base station 1002 may indicate IAB donor capabilities assertion to the IAB node 1006 at 1022b when the IAB donor status indication sent at 1016 indicates that the second base station 1004 should function as an IAB donor for the IAB node 1006. The IAB donor capabilities may be indicated, for example, by the indication component 1742 of the apparatus 1702.

[0094] At 1210, to function as an IAB donor for the IAB node, the first base station may at least one of establish a backhaul RLC channel with the IAB node, send a BAP configuration to the IAB node, send a cell resource configuration for the DU to the IAB node, send an IP configuration to the IAB node, or terminate F1 connectivity with the IAB node. For example, with reference to FIG. 10, to indicate IAB donor functionality / function as an IAB donor for IAB node 1006, the first base station 1002 may, at 1024, (1) establish a backhaul RLC channel with the IAB node, (2) send a BAP configuration to the IAB node, (3) send a cell resource configuration for the DU to the IAB node, (4) send an IP configuration to the IAB node, and / or (5) terminate F1 connectivity with the IAB node. Acting as an IAB donor may be performed, for example, by the establishing component 1740, the terminating component 1744, and / or the transmitting component 1734 of the device 1702.

[0095] At 1212, the first base station may receive a response from the second base station indicating whether at least one of the first base station or the second base station should function as an IAB donor for the IAB node. For example, with reference to FIG. 10 , the first base station 1002 may receive an acceptance or rejection to the IAB donor status indication from the second base station 1004 at 1018. The response may be received, for example, by the receiving component 1730 of the apparatus 1702.

[0096] 13 is a flowchart 1300 of a method of wireless communication. The method may be performed by a base station, e.g., the second base station 1004, which may include the memory 376 and may be the entire second base station 1004 or a component of the second base station 1004, such as the TX processor 316, the RX processor 370, and / or the controller / processor 375. The method may enable the base station to coordinate donor functionality for IAB nodes with the second base station.

[0097] At 1302, a second base station may receive, from a first base station having a first connection with the IAB node, a request for the second base station to establish a second connection with the IAB node. For example, with reference to FIG. 10 , the second base station 1004 may receive, at 1010, a request from the first base station 1002 including the first connection established with the IAB node 1006 at 1008, the request for the second base station 1004 to establish a second connection with the IAB node 1006. The first connection (e.g., established at 1008) may be based on at least one of a first RRC connection or a first F1-C interface, and the second connection (e.g., established at 1012) may be based on at least one of a second RRC connection or a second F1-C interface. The first connection (e.g., established at 1008) and the second connection (e.g., established at 1012) may provide DC to the IAB node 1006, where the DC is associated with at least one of NR-DC, MR-DC, DAPS, or multi-MT connectivity. The request may be received, for example, by a receiving component 1830 of the device 1802.

[0098] At 1304, the second base station may receive an indication from the first base station that at least one of the first base station or the second base station should function as an IAB donor to the IAB node based on the second connection being established with the IAB node. For example, with reference to FIG. 10 , the second base station 1004 may receive at 1016 an IAB donor status indication for the first base station 1002 and / or the second base station 1004 based on the acknowledgment of the second connection sent from the second base station 1004 to the first base station 1002 at 1014. The indication may be received, for example, by the receiving component 1830 of the apparatus 1802.

[0099] At 1306, the second base station may accept or reject the indication received from the first base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node. For example, with reference to FIG. 10 , the second base station 1004 may transmit at 1018 an acceptance or rejection of the IAB donor status indication received from the first base station 1002 in 1016 indicating that the first base station 1002 and / or the second base station 1004 should function as an IAB donor for the IAB node 1006. The indication may be accepted or rejected, for example, by an accept-reject component 1840 of the apparatus 1802.

[0100] 14 is a flowchart 1400 of a method of wireless communication. The method may be performed by a base station, e.g., the second base station 1004, which may include the memory 376 and may be the entire second base station 1004 or a component of the second base station 1004, such as the TX processor 316, the RX processor 370, and / or the controller / processor 375. The method may enable the base station to coordinate donor functionality for IAB nodes with the second base station.

[0101] At 1402, a second base station may receive, from a first base station having a first connection with the IAB node, a request for the second base station to establish a second connection with the IAB node. For example, with reference to FIG. 10 , the second base station 1004 may receive, at 1010, a request from the first base station 1002 including the first connection established with the IAB node 1006 at 1008, the request for the second base station 1004 to establish a second connection with the IAB node 1006. The first connection (e.g., established at 1008) may be based on at least one of a first RRC connection or a first F1-C interface, and the second connection (e.g., established at 1012) may be based on at least one of a second RRC connection or a second F1-C interface. The first connection (e.g., established at 1008) and the second connection (e.g., established at 1012) may provide DC to the IAB node 1006, where the DC is associated with at least one of NR-DC, MR-DC, DAPS, or multi-MT connectivity. The request may be received, for example, by a receiving component 1830 of the device 1802.

[0102] At 1404, the second base station may explicitly or implicitly receive an indication from the first base station that at least one of the first base station or the second base station should function as an IAB donor to the IAB node based on the second connection being established with the IAB node. For example, with reference to FIG. 10 , the second base station 1004 may receive at 1016 an IAB donor status indication for the first base station 1002 and / or the second base station 1004 based on the acknowledgment of the second connection sent from the second base station 1004 to the first base station 1002 at 1014. The indication may be received, for example, by the receiving component 1830 of the apparatus 1802.

[0103] When a first base station (e.g., a master node) determines that a second base station (e.g., a secondary node) is an F1 termination donor node for the IAB node, the first base station may explicitly signal a corresponding request / instruction to the second base station. For example, the first base station may request the second base station to locate an IP address and establish F1 connectivity with the IAB node. Alternatively, when the first base station determines to be an F1 termination donor node for the IAB node, the first base station may not explicitly signal such information to the second base station. Instead, the first base station may send an instruction to the second base station to offload traffic to the second base station (e.g., based on topology redundancy) or to use the communication path between the IAB node and the second base station as an access link (e.g., based on CP-UP separation), in which case the instruction may implicitly indicate to the second base station that the first base station has determined to be an F1 termination donor node for the IAB node.

[0104] The second base station 1004 may receive 1016 an indication that the second base station 1004 should function as an IAB donor for the IAB node 1006. In some configurations, the indication received at 1016 from the first base station 1002 may indicate that the second base station 1004 should provide a subset of IAB donor functionality to the IAB node 1006. The indication received at 1016 from the first base station 1002 may further indicate an indication to the second base station 1004 that the second base station 1004 should establish at least one of a c-plane connection or a u-plane connection with the IAB node 1006 via the first base station 1002 to function as an IAB donor for the IAB node 1006, where the c-plane connection is established in connection with a CP-UP separation procedure and the u-plane connection is established in connection with a topology redundancy procedure. Alternatively, the second base station 1004 may receive 1016 an indication from the first base station 1002 indicating that the first base station 1002 should function as an IAB donor for the IAB node 1006. The indication received from the first base station 1002 at 1016 may further indicate that the first base station 1002 should establish at least one of a c-plane connection or a u-plane connection with the IAB node 1006 via the second base station 1004 to function as an IAB donor for the IAB node 1006. In a further aspect, the indication received from the first base station 1002 at 1016 may indicate that the first base station 1002 and the second base station 1004 should function as IAB donors for the IAB node 1006.

[0105] At 1406, the second base station may indicate IAB donor capability to the IAB node when receiving an indication that the second base station should function as an IAB donor for the IAB node. For example, referring to FIG. 10 , the second base station 1004 may indicate IAB donor capability assertion to the IAB node 1006 at 1022a when the IAB donor status indication received at 1016 indicates that the second base station 1004 should function as an IAB donor for the IAB node 1006. The IAB donor capability may be indicated, for example, by the indication component 1844 of the apparatus 1802.

[0106] At 1408, to function as an IAB donor for the IAB node, the second base station may perform at least one of establishing a backhaul RLC channel with the IAB node, transmitting a BAP configuration to the IAB node, transmitting a cell resource configuration for the DU to the IAB node, transmitting an IP configuration to the IAB node, or terminating F1 connectivity with the IAB node. For example, referring to FIG. 10 , to indicate IAB donor functionality / function as an IAB donor for IAB node 1006, the second base station 1004 may (1) establish a backhaul RLC channel with the IAB node, (2) transmit a BAP configuration to the IAB node, (3) transmit a cell resource configuration for the DU to the IAB node, (4) transmit an IP configuration to the IAB node, and / or (5) terminate F1 connectivity with the IAB node at 1024. Functioning as an IAB donor may be performed, for example, by the establishing component 1842, the terminating component 1846, and / or the transmitting component 1834 of the apparatus 1802.

[0107] At 1410, the second base station may accept or reject the indication received from the first base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node. For example, with reference to FIG. 10 , the second base station 1004 may transmit at 1018 an acceptance or rejection of the IAB donor status indication received from the first base station 1002 at 1016 indicating that the first base station 1002 and / or the second base station 1004 should function as an IAB donor for the IAB node 1006. The indication may be accepted or rejected, for example, by an accept-reject component 1840 of the apparatus 1802.

[0108] At 1412, to accept or reject the indication, the second base station may transmit a response to the first base station indicating whether the second base station will establish at least one of a c-plane connection or a u-plane connection with the IAB node via the first base station to function as an IAB donor for the IAB node. For example, with reference to FIG. 10 , at 1018, to accept or reject the IAB donor status indication received at 1016, the second base station 1004 can include in the acceptance / rejection an indication of whether the second base station 1004 will establish a c-plane connection or a u-plane connection with the IAB node 1006. The response may be transmitted, for example, by the transmitting component 1834 and / or the accept-reject component 1840 of the apparatus 1802.

[0109] At 1414, the second base station may establish a second connection with the IAB node based on the request. For example, referring to FIG. 10 , the second base station 1004 may establish 1012 a second connection with the IAB node 1006 based on the request received at 1010 for the second base station 1004 to establish a second connection with the IAB node 1006. The second connection may be established by, for example, the establishing component 1842 of the apparatus 1802.

[0110] 15 is a flowchart 1500 of a method of wireless communication. The method may be performed by a base station / IAB node, e.g., an IAB node 1006, which may include memory 376 and may be the entire IAB node 1006 or a component of the IAB node 1006, such as the TX processor 316, the RX processor 370, and / or the controller / processor 375. The method improves multi-connectivity for the IAB node.

[0111] An IAB node may establish a first connection with a first base station at 1502. For example, referring to Figure 10, an IAB node 1006 may establish a first connection with a first base station 1002 at 1008. The first connection may be established by, for example, a first connection component 1940 of the device 1902.

[0112] At 1504, the IAB node may establish a second connection with a second base station. For example, referring to FIG. 10, the IAB node 1006 may establish a second connection with the second base station 1004 at 1012. The first connection (e.g., established at 1008) may be based on at least one of a first RRC connection or a first F1-C interface, and the second connection (e.g., established at 1012) may be based on at least one of a second RRC connection or a second F1-C interface. The first connection (e.g., established at 1008) and the second connection (e.g., established at 1012) may provide DC to the IAB node 1006, where the DC is associated with at least one of NR-DC, MR-DC, DAPS, or multi-MT connectivity. The second connection may be established, for example, by a second connection component 1942 of the device 1902.

[0113] At 1506, the IAB node may receive an indication from the first base station or the second base station indicating that at least one of the first base station or the second base station should function as an IAB donor for the IAB node. For example, with reference to FIG. 10 , the IAB node 1006 may receive an IAB donor indication for the first base station 1002 and / or the second base station 1004 at 1020. In some configurations, the IAB node 1006 may receive an indication at 1020 that the second base station 1004 should provide a subset of IAB donor functionality to the IAB node 1006. The IAB node 1006 may be served by an IAB donor based on at least one of a backhaul RLC channel established with the IAB node 1006, a BAP configuration sent to the IAB node 1006, a cell resource configuration for a DU sent to the IAB node 1006, an IP configuration sent to the IAB node 1006, and / or terminated F1 connectivity with the IAB node 1006. The IAB node 1006 may receive 1020 an indication that the second base station 1004 should function as an IAB donor for the IAB node 1006. Alternatively, the IAB node 1006 may receive 1020 an indication that the first base station 1002 should function as an IAB donor for the IAB node 1006. In a further aspect, the IAB node 1006 may receive 1020 an indication that the first base station 1002 and the second base station 1004 should function as IAB donors for the IAB node 1006. The indication may be received by, for example, receiving component 1930 and / or indication component 1944 of device 1902 .

[0114] 16 is a flowchart 1600 of a method of wireless communication. The method may be performed by a base station / IAB node, e.g., an IAB node 1006, which may include memory 376 and may be the entire IAB node 1006 or a component of the IAB node 1006, such as the TX processor 316, the RX processor 370, and / or the controller / processor 375. The method improves multi-connectivity for the IAB node.

[0115] An IAB node may establish a first connection with a first base station at 1602. For example, referring to Figure 10, an IAB node 1006 may establish a first connection with a first base station 1002 at 1008. The first connection may be established by, for example, a first connection component 1940 of the device 1902.

[0116] At 1604, the IAB node may establish a second connection with a second base station. For example, referring to FIG. 10, the IAB node 1006 may establish a second connection with the second base station 1004 at 1012. The first connection (e.g., established at 1008) may be based on at least one of a first RRC connection or a first F1-C interface, and the second connection (e.g., established at 1012) may be based on at least one of a second RRC connection or a second F1-C interface. The first connection (e.g., established at 1008) and the second connection (e.g., established at 1012) may provide DC to the IAB node 1006, where the DC is associated with at least one of NR-DC, MR-DC, DAPS, or multi-MT connectivity. The second connection may be established, for example, by a second connection component 1942 of the device 1902.

[0117] At 1606, the IAB node may receive an indication from the first base station or the second base station implicitly indicating that at least one of the first base station or the second base station should function as an IAB donor for the IAB node. For example, with reference to FIG. 10, the IAB node 1006 may receive an IAB donor indication for the first base station 1002 and / or the second base station 1004 at 1020. If the IAB node establishes NR-DC with the first base station (e.g., master node) and the second base station (e.g., secondary node) before F1 connectivity is established with the IAB node, the IAB node may determine whether the first base station or the second base station is acting as the F1-termination donor node based on which of the first base station or the second base station provides a BAP configuration and / or an IP address to the IAB node. That is, receiving a BAP configuration and / or IP address from a particular base station may implicitly indicate to the IAB node that that particular base station is acting as an F1 termination donor node.

[0118] In some configurations, the IAB node 1006 may receive 1020 an indication that the second base station 1004 should provide a subset of IAB donor functionality to the IAB node 1006. The IAB node 1006 may be served by an IAB donor based on at least one of a backhaul RLC channel established with the IAB node 1006, a BAP configuration sent to the IAB node 1006, a cell resource configuration for DUs sent to the IAB node 1006, an IP configuration sent to the IAB node 1006, and / or terminated F1 connectivity with the IAB node 1006. The IAB node 1006 may receive 1020 an indication that the second base station 1004 should function as an IAB donor for the IAB node 1006. Alternatively, the IAB node 1006 may receive 1020 an indication that the first base station 1002 should function as an IAB donor for the IAB node 1006. In a further aspect, the IAB node 1006 may receive 1020 an indication that the first base station 1002 and the second base station 1004 should function as IAB donors for the IAB node 1006. The indication may be received, for example, by the receiving component 1930 and / or the indicating component 1944 of the apparatus 1902.

[0119] At 1608, the IAB node may receive an assertion for at least a subset of the IAB donor capabilities from the first base station or the second base station. For example, with reference to FIG. 10 , the IAB node 1006 may receive a first IAB donor capabilities assertion from the second base station 1004 at 1022a, and / or the IAB node 1006 may receive a second IAB donor capabilities assertion from the first base station 1002 at 1022b. The assertion may be received, for example, by a receiving component 1930 of the apparatus 1902.

[0120] FIG. 17 is a diagram 1700 illustrating an example of a hardware implementation of an apparatus 1702. The apparatus 1702 is a BS and includes a baseband unit 1704. The baseband unit 1704 may communicate with the IAB node 103, the second base station 102 / 180, and / or the UE 104 via a cellular RF transceiver 1722. The baseband unit 1704 may include a computer-readable medium / memory. The baseband unit 1704 is responsible for general processing, including the execution of software stored on the computer-readable medium / memory. The software, when executed by the baseband unit 1704, causes the baseband unit 1704 to perform the various functions described above. The computer-readable medium / memory may be used to store data manipulated by the baseband unit 1704 when executing the software. The baseband unit 1704 further includes a receiving component 1730, a communications manager 1732, and a transmitting component 1734. The communications manager 1732 includes one or more of the illustrated components. The components in the communications manager 1732 may be stored in a computer-readable medium / memory and / or configured as hardware in the baseband unit 1704. The baseband unit 1704 may be a component of the first wireless device 310 and may include the memory 376 and / or at least one of the TX processor 316, the RX processor 370, and the controller / processor 375.

[0121] The communications manager 1732 includes an establishing component 1740 configured to establish a first connection with the IAB node 103 and establish a backhaul RLC channel with the IAB node 103, e.g., as described with respect to 1102, 1202, and 1210. The communications manager 1732 further includes an indicating component 1742 configured to indicate (e.g., explicitly or implicitly) to the second base station 102 / 180 that at least one of the first base station (e.g., device 1702) or the second base station should function as an IAB donor for the IAB node based on the second connection being established with the IAB node 103, e.g., as described with respect to 1106, 1206, and 1208, and to indicate IAB donor functionality to the IAB node when the device 1702 indicates to the second base station that the first base station will function as an IAB donor for the IAB node. The communications manager 1732 further includes a termination component 1744 configured to terminate F1 connectivity with the IAB node 103, for example, as described with respect to 1210.

[0122] The receiving component 1730 may be configured to receive a response from the second base station 102 / 180 indicating whether at least one of the first base station (e.g., apparatus 1702) or the second base station should function as an IAB donor to the IAB node, e.g., as described with respect to 1212. The transmitting component 1734 may be configured to send a request to the second base station for the second base station to establish a second connection with the IAB node, send a BAP configuration to the IAB node, send a cell resource configuration for the DU to the IAB node, and send an IP configuration to the IAB node, e.g., as described with respect to 1104, 1204, and 1210.

[0123] The apparatus may include additional components that perform each of the blocks of the algorithms in the above-described flowcharts of Figures 11-12. Thus, each block in the above-described flowcharts of Figures 11-12 may be performed by a component, and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to perform the described process / algorithm, implemented by a processor configured to execute the described process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0124] In one configuration, the apparatus 1702, particularly the baseband unit 1704, includes means for establishing a first connection with the IAB node, means for transmitting a request to the second base station for the second base station to establish a second connection with the IAB node, and means for indicating to the second base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node based on the second connection being established with the IAB node. The apparatus 1702 further includes means for indicating IAB donor functionality to the IAB node. The apparatus 1702 further includes means for establishing a backhaul RLC channel with the IAB node, means for transmitting a BAP configuration to the IAB node, means for transmitting a cell resource configuration for the DU to the IAB node, means for transmitting an IP configuration to the IAB node, and means for terminating F1 connectivity with the IAB node. The apparatus 1702 further includes means for receiving a response from the second base station indicating whether at least one of the first base station or the second base station should function as an IAB donor for the IAB node. The aforementioned means may be one or more of the aforementioned components of the apparatus 1702 configured to perform the functions recited by the aforementioned means. As described above, the apparatus 1702 may include the TX processor 316, the RX processor 370, and the controller / processor 375. Thus, in one configuration, the aforementioned means may be the TX processor 316, the RX processor 370, and the controller / processor 375 configured to perform the functions recited by the aforementioned means.

[0125] FIG. 18 is a diagram 1800 illustrating an example of a hardware implementation of an apparatus 1802. The apparatus 1802 is a BS and includes a baseband unit 1804. The baseband unit 1804 may communicate with a base station 102 / 180, an IAB node 103, and / or a UE 104 via a cellular RF transceiver 1822. The baseband unit 1804 may include a computer-readable medium / memory. The baseband unit 1804 is responsible for general processing, including the execution of software stored on the computer-readable medium / memory. The software, when executed by the baseband unit 1804, causes the baseband unit 1804 to perform the various functions described above. The computer-readable medium / memory may be used to store data manipulated by the baseband unit 1804 when executing the software. The baseband unit 1804 further includes a receiving component 1830, a communications manager 1832, and a transmitting component 1834. The communications manager 1832 includes one or more of the illustrated components. The components in the communications manager 1832 may be stored in a computer-readable medium / memory and / or configured as hardware in the baseband unit 1804. The baseband unit 1804 may be a component of the first wireless device 310 and may include the memory 376 and / or at least one of the TX processor 316, the RX processor 370, and the controller / processor 375.

[0126] The communications manager 1832 includes an accept-reject component 1840 configured to accept or reject an indication received from a first base station that at least one of the first base station or the second base station (e.g., device 1802) should function as an IAB donor for the IAB node 103, e.g., as described with respect to 1306 and 1410. The communications manager 1832 further includes an establishing component 1842 configured to establish a second connection with the IAB node 103 and establish a backhaul RLC channel with the IAB node 103 based on the request, e.g., as described with respect to 1414 and 1408. The communications manager 1832 further includes an indicating component 1844 configured to indicate IAB donor functionality to the IAB node when the second base station (e.g., device 1802) receives an indication that the second base station should function as an IAB donor for the IAB node, e.g., as described with respect to 1406. The communications manager 1832 further includes a termination component 1846 configured to terminate F1 connectivity with the IAB node, for example, as described with respect to 1408 .

[0127] The receiving component 1830 is configured to receive, for example, as described with respect to 1302, 1304, 1402, and 1404, a request from a first base station having a first connection with the IAB node to a second base station (e.g., device 1802) to establish a second connection with the IAB node, and to receive (e.g., explicitly or implicitly) an indication from the first base station that at least one of the first base station or the second base station (e.g., device 1802) should function as an IAB donor for the IAB node 103 based on the second connection being established with the IAB node 103. The transmitting component 1834 is configured to, for example, transmit a BAP configuration to the IAB node 103, transmit a cell resource configuration for the DU to the IAB node 103, transmit an IP configuration to the IAB node 103, and transmit a response to the first base station indicating whether the second base station (e.g., device 1802) will establish at least one of a c-plane connection or a u-plane connection with the IAB node 103 via the first base station to function as an IAB donor for the IAB node 103, as described with respect to 1408 and 1412.

[0128] The apparatus may include additional components that perform each of the blocks of the algorithms in the above-described flowcharts of Figures 13-14. Thus, each block in the above-described flowcharts of Figures 13-14 may be performed by a component, and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to perform the described process / algorithm, implemented by a processor configured to execute the described process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0129] In one configuration, the apparatus 1802, particularly the baseband unit 1804, includes: means for receiving, from a first base station having a first connection with the IAB node, a request for a second base station to establish a second connection with the IAB node; means for receiving, based on the second connection being established with the IAB node, an indication from the first base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node; and means for accepting or rejecting the indication received from the first base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node. The means for accepting or rejecting the indication is further configured to transmit a response to the first base station indicating whether the second base station will establish at least one of a c-plane connection or a u-plane connection with the IAB node via the first base station to function as an IAB donor for the IAB node. The apparatus 1802 further includes means for establishing the second connection with the IAB node based on the request. The apparatus 1802 further includes means for indicating IAB donor functionality to the IAB node when the second base station should function as an IAB donor for the IAB node. The apparatus 1802 further includes means for establishing a backhaul RLC channel with the IAB node, means for transmitting a BAP configuration to the IAB node, means for transmitting a cell resource configuration for the DU to the IAB node, means for transmitting an IP configuration to the IAB node, and means for terminating F1 connectivity with the IAB node.

[0130] The aforementioned means may be one or more of the aforementioned components of the apparatus 1802 configured to perform the functions recited by the aforementioned means. As described above, the apparatus 1802 may include the TX processor 316, the RX processor 370, and the controller / processor 375. Thus, in one configuration, the aforementioned means may be the TX processor 316, the RX processor 370, and the controller / processor 375 configured to perform the functions recited by the aforementioned means.

[0131] FIG. 19 is a diagram 1900 illustrating an example of a hardware implementation of an apparatus 1902. The apparatus 1902 is an IAB and includes a baseband unit 1904. The baseband unit 1904 may communicate with the first and second base stations 102 / 180, another IAB node 103, and / or the UE 104 via a cellular RF transceiver 1922. The baseband unit 1904 may include a computer-readable medium / memory. The baseband unit 1904 is responsible for general processing, including the execution of software stored on the computer-readable medium / memory. The software, when executed by the baseband unit 1904, causes the baseband unit 1904 to perform the various functions described above. The computer-readable medium / memory may be used to store data manipulated by the baseband unit 1904 when executing the software. The baseband unit 1904 further includes a receiving component 1930, a communications manager 1932, and a transmitting component 1934. The communications manager 1932 includes one or more of the illustrated components. The components in the communications manager 1932 may be stored in a computer-readable medium / memory and / or configured as hardware in the baseband unit 1904. The baseband unit 1904 may be a component of the first wireless device 310 or the second wireless device 350 and may include a memory 360 or 376 and / or at least one of the TX processor 316 or 368, the RX processor 356 or 370, and the controller / processor 359 or 375.

[0132] Communications manager 1932 includes a first connection component 1940 configured to establish a first connection with a first base station, e.g., as described with respect to 1502 and 1602, and a second connection component 1942 configured to establish a second connection with a second base station, e.g., as described with respect to 1504 and 1604. Communications manager 1932 includes an indication component 1944 configured to receive, via receiving component 1930, an indication from the first base station or the second base station indicating (e.g., implicitly) that at least one of the first base station or the second base station should function as an IAB donor for the IAB node, and to receive an assertion for at least a subset of IAB donor capabilities from the first base station or the second base station, e.g., as described with respect to 1506, 1606, and 1608.

[0133] The apparatus may include additional components that perform each of the blocks of the algorithms in the above-described flowcharts of Figures 15-16. Thus, each block in the above-described flowcharts of Figures 15-16 may be performed by a component, and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to perform the described process / algorithm, implemented by a processor configured to execute the described process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0134] In one configuration, the apparatus 1902, particularly the baseband unit 1904, includes means for establishing a first connection with a first base station, means for establishing a second connection with a second base station, and means for receiving an indication from the first base station indicating that at least one of the first base station or the second base station should function as an IAB donor for the IAB node. The apparatus 1902 further includes means for receiving an assertion for at least a subset of IAB donor capabilities from the first base station or the second base station.

[0135] The aforementioned means may be one or more of the aforementioned components of the apparatus 1902 configured to perform the functions recited by the aforementioned means. As explained above, the apparatus 1902 may include the TX processor 316, the RX processor 370, and the controller / processor 375. Thus, in one configuration, the aforementioned means may be the TX processor 316, the RX processor 370, and the controller / processor 375 configured to perform the functions recited by the aforementioned means.

[0136] It is understood that the specific order or hierarchy of blocks in the disclosed processes / flowcharts is illustrative of example approaches. Based on design preferences, it is understood that the specific order or hierarchy of blocks in the processes / flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in an example order and are not limited to the specific order or hierarchy presented.

[0137] The above description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Accordingly, the claims are not intended to be limited to the aspects set forth herein but are to be accorded the widest scope consistent with the claim language, and references to elements in the singular do not mean "one and only one," but rather "one or more," unless so expressly stated. Terms such as "if," "when," and "while" should be construed to mean "under the condition that," rather than implying an immediate time relationship or reaction. That is, these phrases, such as "when," do not imply immediate action in response to or during the occurrence of an action, but merely imply that an action occurs when a condition is met, but without requiring any specific or immediate time constraint for the action to occur. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects. Unless expressly stated otherwise, the term "some" refers to one or more. Combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," "A, B, C, or any combination thereof," include any combination of A, B, and / or C, and may include multiple As, multiple Bs, or multiple Cs.Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," "A, B, C, or any combination thereof" may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, and any such combination may include one or more members of A, B, or C. All structural and functional equivalents to the elements of the various embodiments described throughout this disclosure that are known or later become known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is made public, regardless of whether such disclosure is expressly recited in the claims. Words such as "module," "mechanism," "element," "device," and the like may not be substitutes for the word "means." Thus, no claim element should be construed as a means-plus-function unless the element is expressly recited using the phrase "means for."

[0138] The following aspects are exemplary only and may be combined with other aspects or teachings described herein without limitation.

[0139] Aspect 1 is a method of wireless communication at a first base station, including: establishing a first connection with an IAB node; transmitting a request to the second base station for the second base station to establish a second connection with the IAB node; and indicating to the second base station, based on the second connection being established with the IAB node, that at least one of the first base station or the second base station should function as an IAB donor for the IAB node.

[0140] Aspect 2 may be combined with aspect 1 and includes the first connection being based on at least one of a first RRC connection or a first F1-C interface, and the second connection being based on at least one of a second RRC connection or a second F1-C interface.

[0141] Embodiment 3 may be combined with any of embodiments 1 to 2, and includes the first connection and the second connection providing DC to the IAB node, and the DC being associated with at least one of NR-DC, MR-DC, DAPS, or multi-MT connectivity.

[0142] Aspect 4 may be combined with any of aspects 1 to 3 and includes a first base station indicating to a second base station that the first base station will function as an IAB donor to the IAB node, and this aspect further includes indicating the IAB donor functionality to the IAB node.

[0143] Aspect 5 may be combined with any of aspects 1 to 4, and includes wherein acting as an IAB donor to the IAB node includes at least one of establishing a backhaul RLC channel with the IAB node, sending a BAP configuration to the IAB node, sending a cell resource configuration for the DU to the IAB node, sending an IP configuration to the IAB node, or terminating F1 connectivity with the IAB node.

[0144] Aspect 6 may be combined with any of aspects 1 to 5 and includes the first base station indicating to the second base station that the second base station should function as an IAB donor for the IAB node.

[0145] Aspect 7 may be combined with any of aspects 1 to 6, wherein the instruction to the second base station further indicates that the second base station should establish at least one of a c-plane connection or a u-plane connection with the IAB node via the first base station to function as an IAB donor for the IAB node.

[0146] Example 8 may be combined with any of Examples 1 to 5 and includes a first base station indicating to a second base station that the first base station should function as an IAB donor for the IAB node.

[0147] Aspect 9 may be combined with any of aspects 1 to 5 or 8, and the instruction to the second base station further indicates that the first base station should establish at least one of a c-plane connection or a u-plane connection with the IAB node via the second base station to function as an IAB donor for the IAB node, wherein the c-plane connection is established in connection with a control plane-user plane (CP-UP) separation procedure, and the u-plane connection is established in connection with a topology redundancy procedure.

[0148] Example 10 may be combined with any of Examples 1 to 9 and further includes receiving a response from the second base station indicating whether at least one of the first base station or the second base station should function as an IAB donor for the IAB node.

[0149] Example 11 may be combined with any of Examples 1 to 10 and includes a first base station indicating to a second base station that the first base station and the second base station should function as IAB donors to an IAB node.

[0150] Example 12 may be combined with any of Examples 1 to 3 or 5 to 11 and includes the first base station indicating to the second base station that the second base station should provide a subset of IAB donor functionality to the IAB node.

[0151] Aspect 13 is a method of wireless communication at a second base station, including: receiving a request from a first base station having a first connection with an IAB node to a second base station to establish a second connection with the IAB node; receiving an indication from the first base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node based on the second connection being established with the IAB node; and accepting or rejecting the indication received from the first base station that at least one of the first base station or the second base station should function as an IAB donor for the IAB node.

[0152] Aspect 14 may be combined with aspect 13 and further includes establishing a second connection with the IAB node based on the request.

[0153] Example 15 may be combined with any of Examples 13 to 14, and includes the first connection being based on at least one of a first RRC connection or a first F1-C interface, and the second connection being based on at least one of a second RRC connection or a second F1-C interface.

[0154] Example 16 may be combined with any of Examples 13 to 15 and includes the first connection and the second connection providing DC to the IAB node, and the DC being associated with at least one of NR-DC, MR-DC, DAPS, or multi-MT connectivity.

[0155] Aspect 17 may be combined with any of aspects 13 to 16 and includes the second base station receiving an indication that the second base station should function as an IAB donor for the IAB node, and the aspect further includes indicating the IAB donor functionality to the IAB node when the second base station should function as an IAB donor for the IAB node.

[0156] Example 18 may be combined with any of Examples 13 to 17, and includes wherein acting as an IAB donor to the IAB node includes at least one of establishing a backhaul RLC channel with the IAB node, sending a BAP configuration to the IAB node, sending a cell resource configuration for the DU to the IAB node, sending an IP configuration to the IAB node, or terminating F1 connectivity with the IAB node.

[0157] Aspect 19 may be combined with any of aspects 13 to 18 and includes the second base station receiving an indication that the second base station should function as an IAB donor for the IAB node.

[0158] Example 20 may be combined with any of Examples 13 to 19, and includes the instruction received from the first base station further indicating to the second base station that the second base station should establish at least one of a c-plane connection or a u-plane connection with the IAB node via the first base station to function as an IAB donor for the IAB node.

[0159] Example 21 may be combined with any of Examples 13 to 18 and includes the second base station receiving an indication from the first base station indicating that the first base station should function as an IAB donor for the IAB node.

[0160] Example 22 may be combined with any of Examples 13 to 18 or 21, and includes the instruction received from the first base station further indicating that the first base station should establish at least one of a c-plane connection or a u-plane connection with the IAB node via the second base station to function as an IAB donor for the IAB node, wherein the c-plane connection is established in connection with a control plane-user plane (CP-UP) separation procedure and the u-plane connection is established in connection with a topology redundancy procedure.

[0161] Aspect 23 may be combined with any of aspects 13 to 22, and further includes transmitting a response to the first base station indicating whether the step of accepting or rejecting the instruction results in the second base station establishing at least one of a c-plane connection or a u-plane connection with the IAB node via the first base station to function as an IAB donor for the IAB node.

[0162] Example 24 may be combined with any of Examples 13 to 23 and includes the indication received from the first base station indicating that the first base station and the second base station should function as IAB donors to the IAB node.

[0163] Example 25 may be combined with any of Examples 13 to 16 or 18 to 24, and includes the indication received from the first base station indicating that the second base station should provide a subset of the IAB donor functionality to the IAB node.

[0164] Aspect 26 is a method of wireless communication in an IAB node, including: establishing a first connection with a first base station; establishing a second connection with a second base station; and receiving an indication from the first base station or the second base station indicating that at least one of the first base station or the second base station is to function as an IAB donor for the IAB node.

[0165] Aspect 27 may be combined with aspect 26 and includes the first connection being based on at least one of a first RRC connection or a first F1-C interface, and the second connection being based on at least one of a second RRC connection or a second F1-C interface.

[0166] Example 28 may be combined with any of Examples 26 to 27 and includes the first connection and the second connection providing DC to the IAB node, and the DC being associated with at least one of NR-DC, MR-DC, DAPS, or multi-MT connectivity.

[0167] Example 29 may be combined with any of Examples 26 to 28 and further includes receiving an assertion for at least a subset of the IAB donor capabilities from the first base station or the second base station.

[0168] Example 30 may be combined with any of examples 26 to 29, and includes wherein acting as an IAB donor to the IAB node includes at least one of establishing a backhaul RLC channel with the IAB node, sending a BAP configuration to the IAB node, sending a cell resource configuration for the DU to the IAB node, sending an IP configuration to the IAB node, or terminating F1 connectivity with the IAB node.

[0169] Example 31 may be combined with any of Examples 26 to 30 and includes the IAB node receiving an indication that the second base station is to function as an IAB donor for the IAB node.

[0170] Example 32 may be combined with any of Examples 26 to 30 and includes the IAB node receiving an indication that the first base station is to function as an IAB donor for the IAB node.

[0171] Example 33 may be combined with any of Examples 26 to 32 and includes the IAB node receiving an indication that the first base station and the second base station should function as IAB donors to the IAB node.

[0172] Example 34 may be combined with any of examples 26 to 33 and includes the IAB node receiving an indication that the second base station should provide a subset of IAB donor functionality to the IAB node.

[0173] Aspect 35 is an apparatus for wireless communication in a first base station, including at least one processor, coupled to a memory, configured to implement a method according to any of aspects 1 to 12.

[0174] Aspect 36 is an apparatus for wireless communication in a second base station, including at least one processor, coupled to a memory, configured to implement a method according to any of aspects 13 to 25.

[0175] Example 37 is an apparatus for wireless communication in an IAB node, including at least one processor, coupled to a memory, configured to implement a method described in any of Examples 26 to 34.

[0176] Example 38 is an apparatus for wireless communication in a first base station, comprising means for implementing the method of any of Examples 1 to 12.

[0177] Example 39 is an apparatus for wireless communication in a second base station, comprising means for implementing the method of any of Examples 14 to 25.

[0178] Example 40 is an apparatus for wireless communication in an IAB node, comprising means for implementing the method of any of Examples 27 to 34.

[0179] Aspect 41 is a computer-readable medium storing computer-executable code that, when executed by a processor, causes the processor to implement a method according to any of aspects 1-12.

[0180] Aspect 42 is a computer-readable medium storing computer-executable code that, when executed by a processor, causes the processor to implement a method according to any of aspects 14 to 25.

[0181] Aspect 43 is a computer-readable medium storing computer-executable code that, when executed by a processor, causes the processor to implement a method according to any of aspects 27 to 34. [Explanation of symbols]

[0182] 100 Wireless Communication Systems and Access Networks 102 base station, macro base station, first base station 102' Small Cell 103 IAB nodes 104UE 110 Coverage Area 110' coverage area 120 Communication Links 132 First Backhaul Link 134 Third Backhaul Link 150 Wi-Fi access points (APs) 152 Wi-Fi stations (STA) 154 communication links 158 Device-to-Device (D2D) Communication Links 160 Evolved Packet Core (EPC) 162 Mobility Management Entity (MME) 164 MME 166 Serving Gateway 168 Multimedia Broadcast Multicast Service (MBMS) Gateway 170 Broadcast Multicast Service Center (BM-SC) 172 Packet Data Network (PDN) Gateway 174 Home Subscriber Server (HSS) 176 IP Services 180 mm-wave base station, base station, first base station 182 Beamforming 182' Sending direction 182'' receiving direction 184 Second Backhaul Link 190 Core Network 191 IAB Donor Decision Components 192 Access and Mobility Management Function (AMF) 193 AMF 194 Session Management Facility (SMF) 195 User Plane Function (UPF) 196 Integrated Data Management (UDM) 197 IP Services 198 Integrated Access and Backhaul (IAB) Donor Designated Components 199 IAB Donor Acceptance-Rejection Components 200 Figures 230 Figures 250 Figures 280 Figures 310 First Wireless Device 316 Transmit (TX) Processor 318 Transmitter TX, Receiver RX 320 Antenna 350 Second Wireless Device, UE 352 Antenna 354 Receiver RX, Transmitter TX 356 Receive (RX) Processor 358 Channel Estimator 359 Controller / Processor 360 memory 368 TX Processor 370 Receive (RX) Processor 375 Controller / Processor 376 memory 400 IAB Network 410 IAB donors 420 IAB nodes 430 UE 450 Wireline Backhaul Link 460 backhaul links 470 Access Link 490 Core Network 500 IAB Network 510 IAB Donor Nodes 520a IAB node, child IAB node, parent node 520b IAB node, child IAB node 530a~530c UE 560 Backhaul Link 570 Access Link 590 Core Network 591 Wired Connection 600 Figures 602 CU 604 DU 606a IAB node 606b IAB node 606c IAB node 608a UE 608b UE 700 Figures 702a IAB Node 2 704a IAB Node 1 704b IAB Node 1 706a IAB Donor DU 706b IA Donor DU 708a IAB Donor CU 708b IAB Donor CU 710 Master NG-RAN (M-NG-RAN) Node 712 Secondary NG-RAN (S-NG-RAN) Node 750 Figures 800 Figures 802 IAB3 node, IAB3-DU 803 IAB3 node, IAB3-MT 804 IAB1 node 806 Donor 1-DU 808 Donor 1-CU 810 IAB2 nodes 812 Donor 2-DU 814 Donor 2-CU 816a First UE 816b First UE 818a Second UE 818b Second UE 820 IAB4 nodes 850 Figures 900 Dual Connection 902 IAB nodes 904 First Base Station 906 Second Base Station 908 Parent DU1 910 Parent DU2 912 Donor CU1 914 Donor CU2 920 Dual Connection 940 Dual Connection 1002 first base station 1004 second base station 1006 IAB nodes 1100 Flowchart 1200 Flowchart 1300 Flowchart 1400 Flowchart 1500 Flowchart 1600 Flowchart 1700 Figures 1702 Equipment 1704 Baseband Unit 1722 Cellular RF Transceiver 1730 Receiving Component 1732 Communications Manager 1734 Transmission Components 1740 Establishment Components 1742 Instruction component 1744 End Component 1800 Figures 1802 equipment 1804 Baseband Unit 1822 Cellular RF Transceiver 1830 Receiving Component 1832 Communications Manager 1834 Transmission Components 1840 Acceptance-Rejection Components 1842 Establishment Components 1844 Instruction component 1846 End Component 1900 Figure 1902 equipment 1904 Baseband Unit 1922 Cellular RF Transceiver 1930 Receiving Component 1932 Communications Manager 1934 Transmission Components 1940 First connection component 1942 Second connecting component 1944 Instruction Component

Claims

1. 1. An apparatus for wireless communication at a first base station, comprising: a memory configured to store instructions; at least one processor configured to be communicatively coupled to the memory; wherein the at least one processor is configured to execute the instructions, which when executed, establishing a first connection with an integrated access and backhaul (IAB) node; sending a request to a second base station to establish a second connection with the IAB node; transmitting an IAB donor status indication to the second base station based on the second connection being established with the IAB node, that at least one of the first base station or the second base station should function as an IAB donor to the IAB node, the IAB donor status indication indicating that the second base station should establish a control plane (c-plane) connection or a user plane (u-plane) connection with the IAB node; receiving a response from the second base station indicating acceptance or rejection of the IAB donor status indication; configured to cause the device to Device.

2. 2. The apparatus of claim 1, wherein the first connection is based on at least one of a first radio resource control (RRC) connection or a first F1-control (F1-C) interface, and the second connection is based on at least one of a second RRC connection or a second F1-C interface.

3. 2. The apparatus of claim 1, wherein the first connection and the second connection provide dual connectivity (DC) to the IAB node, the DC being associated with at least one of New Radio DC (NR-DC), Multi-Radio DC (MR-DC), Dual Active Protocol Stack (DAPS), or Multi-Mobile Termination (Multi-MT) connectivity.

4. to indicate to the second base station that the first base station will function as the IAB donor for the IAB node, the at least one processor: IAB donor function is indicated to the IAB node. The apparatus of claim 1 , further configured to:

5. To function as the IAB donor for the IAB node, the at least one processor: establishing a backhaul radio link control (RLC) channel with the IAB node; sending a backhaul adaptation protocol (BAP) configuration to the IAB node; transmitting a cell resource configuration for a distributed unit (DU) to the IAB node; sending an Internet Protocol (IP) configuration to said IAB node; or Terminating F1 connectivity with said IAB node The apparatus of claim 1 , configured to perform at least one of:

6. 10. The apparatus of claim 1, wherein the at least one processor is configured to indicate to the second base station that the second base station should function as the IAB donor for the IAB node.

7. 10. The apparatus of claim 1, wherein the at least one processor is further configured to indicate to the second base station that the first base station should function as the IAB donor for the IAB node.

8. 8. The apparatus of claim 7, wherein the at least one processor is further configured to indicate to the second base station that the first base station should establish at least one of a c-plane connection or a u-plane connection with the IAB node via the second base station to function as the IAB donor for the IAB node, wherein the c-plane connection is established in connection with a control plane-user plane (CP-UP) separation procedure and the u-plane connection is established in connection with a topology redundancy procedure.

9. 10. The apparatus of claim 1, wherein the at least one processor is further configured to receive a response from the second base station indicating whether the at least one of the first base station or the second base station should function as the IAB donor for the IAB node.

10. the first base station indicates to the second base station that the first base station and the second base station should function as an IAB donor for the IAB node; or 10. The apparatus of claim 1, wherein the first base station indicates to the second base station that the second base station should provide a subset of IAB donor capabilities to the IAB node.

11. 1. An apparatus for wireless communication at a second base station, comprising: a memory configured to store instructions; at least one processor configured to be communicatively coupled to the memory; wherein the at least one processor is configured to execute the instructions, which when executed, receiving, from a first base station having a first connection with an integrated access and backhaul (IAB) node, a request for the second base station to establish a second connection with the IAB node; receiving an IAB donor status indication from the first base station that at least one of the first base station or the second base station should function as an IAB donor to the IAB node based on the second connection being established with the IAB node, the IAB donor status indication indicating that the second base station should establish a control plane (c-plane) connection or a user plane (u-plane) connection with the IAB node; accepting or rejecting the IAB donor status indication received from the first base station that the at least one of the first base station or the second base station should function as the IAB donor for the IAB node; transmitting a response to the first base station indicating acceptance or rejection of the IAB donor status indication; configured to cause the device to Device.

12. 1. An apparatus for wireless communication in an integrated access and backhaul (IAB) node, comprising: a memory configured to store instructions; at least one processor configured to be communicatively coupled to the memory; wherein the at least one processor is configured to execute the instructions, which when executed, establishing a first connection with a first base station; establishing a second connection with a second base station; receiving an indication from the first base station or the second base station indicating that at least one of the first base station or the second base station should function as an IAB donor for the IAB node; An apparatus configured to: and a device according to any one of claims 1 to 10 or a device according to claim 11. system.

13. 1. A method of wireless communication in a first base station, comprising: establishing a first connection with an integrated access and backhaul (IAB) node; sending a request to a second base station to establish a second connection with the IAB node; transmitting an IAB donor status indication to the second base station based on the second connection being established with the IAB node, that at least one of the first base station or the second base station should function as an IAB donor to the IAB node, the IAB donor status indication indicating that the second base station should establish a control plane (c-plane) connection or a user plane (u-plane) connection with the IAB node; receiving a response from the second base station indicating acceptance or rejection of the IAB donor status indication; A method comprising:

14. 1. A method of wireless communication in a second base station, comprising: receiving, from a first base station having a first connection with an integrated access and backhaul (IAB) node, a request for the second base station to establish a second connection with the IAB node; receiving an IAB donor status indication from the first base station that at least one of the first base station or the second base station should function as an IAB donor to the IAB node based on the second connection being established with the IAB node, the IAB donor status indication indicating that the second base station should establish a control plane (c-plane) connection or a user plane (u-plane) connection with the IAB node; accepting or rejecting the IAB donor status indication received from the first base station that the at least one of the first base station or the second base station should function as the IAB donor for the IAB node; and transmitting a response to the first base station indicating acceptance or rejection of the IAB donor status indication. method.

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