CN117730578A

CN117730578A - Signaling support for different timing situations in an IAB node

Info

Publication number: CN117730578A
Application number: CN202280049388.7A
Authority: CN
Inventors: N·阿贝迪尼; L·布莱森特; J·罗
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2021-08-24
Filing date: 2022-07-29
Publication date: 2024-03-19

Abstract

An Integrated Access and Backhaul (IAB) node receives a time difference parameter from a parent IAB node for over-the-air (OTA) synchronization in an IAB network. The IAB node adjusts the sending or receiving of the IAB node based on a time difference parameter for one of the multiple types of IAB node alignments.

Description

Signaling support for different timing situations in an IAB node

Cross Reference to Related Applications

This application claims the benefit and priority of the following applications: U.S. provisional patent application Ser. No. 63/236,663, entitled "Signaling Support for Different Timing Cases in IAB Nodes," filed 8/24 at 2021; and U.S. non-provisional patent application Ser. No. 17/811,005, entitled "SIGNALING SUPPORT FOR DIFFERENT TIMING CASES IN IAB NODES," filed on 7/6 of 2022, the entire contents of which are expressly incorporated herein by reference.

Technical Field

The present disclosure relates generally to communication systems, and more particularly to communication in an Integrated Access and Backhaul (IAB) network.

Background

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcast. A typical wireless communication system may employ multiple-access techniques capable of supporting communication with multiple users by sharing the available system resources. Examples of such multiple-access techniques 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.

These multiple access techniques have been employed in various telecommunications standards to provide a common protocol that enables different wireless devices to communicate at the urban, national, regional, and even global levels. An example telecommunications standard is 5G New Radio (NR). The 5G NR is part of the continuous mobile broadband evolution promulgated by the third generation partnership project (3 GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the internet of things (IoT)), and other requirements. The 5G NR includes services associated with enhanced mobile broadband (emmbb), large-scale machine type communication (emtc), and ultra-reliable low latency communication (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There is a need for further improvements in 5G NR technology. These improvements may also be applicable to other multiple access techniques and telecommunication standards employing these techniques.

Disclosure of Invention

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. This summary does not identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In one aspect of the disclosure, a method, computer-readable medium, and apparatus at an Integrated Access and Backhaul (IAB) node are provided. The apparatus receives a time difference parameter from a parent IAB node for over-the-air (OTA) synchronization in an IAB network and adjusts transmission or reception of the IAB node based on the time difference parameter for one of a plurality of types of IAB node alignments.

In one aspect of the disclosure, a method, computer-readable medium, and apparatus at a parent IAB node are provided. The apparatus transmits or receives communications with an IAB node that is a child node of a parent IAB node and transmits a time difference parameter for over-the-air synchronization in the IAB network that is applicable to one of a plurality of types of IAB node alignments.

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

Drawings

Fig. 1 is a diagram illustrating an example of a wireless communication system and an access network in accordance with various aspects of the present disclosure.

Fig. 2A is a diagram illustrating an example of a first frame in accordance with aspects of the present disclosure.

Fig. 2B is a diagram illustrating an example of DL channels within a subframe according to aspects of the present disclosure.

Fig. 2C is a diagram illustrating an example of a second frame in accordance with aspects of the present disclosure.

Fig. 2D is a diagram illustrating an example of UL channels within a subframe in accordance with various aspects of the present disclosure.

Fig. 3 is a diagram illustrating an example of an IAB node and a User Equipment (UE) in a network in accordance with aspects of the present disclosure.

Fig. 4 is a diagram illustrating an example IAB network in accordance with aspects of the present disclosure.

Fig. 5 is a diagram illustrating an example IAB network and its components in accordance with aspects of the present disclosure.

Fig. 6 is a diagram illustrating an example connection for an IAB network in accordance with aspects of the present disclosure.

Fig. 7A, 7B, and 7C illustrate various examples of different types of timing alignment for an IAB node according to aspects of the present disclosure.

Fig. 8 illustrates a timing diagram for communication with a parent IAB node and a child IAB node in accordance with aspects of the present disclosure.

Fig. 9 is a communication flow diagram illustrating example aspects of timing alignment based on time difference parameters indicated by a parent IAB node according to aspects of the present disclosure.

Fig. 10 is a communication flow diagram illustrating example aspects of timing alignment based on a time difference parameter indicated by a parent IAB node according to aspects of the present disclosure.

Fig. 11 is a communication flow diagram illustrating example aspects of timing alignment based on a time difference parameter indicated by a parent IAB node in accordance with aspects of the present disclosure.

Fig. 12 is a flow chart of a method of wireless communication including timing adjustment based on a time difference parameter from a parent IAB node in accordance with aspects of the present disclosure.

Fig. 13 is a flow chart of a method of wireless communication including indicating a time difference parameter to a child IAB node in accordance with aspects of the present disclosure.

Fig. 14 is a diagram illustrating an example of a hardware implementation of an apparatus employing a processing system that may be configured to transmit and/or receive time difference parameters associated with one of a plurality of types of timing alignment.

Fig. 15 shows a diagram illustrating an example split base station architecture.

Detailed Description

The method may enable the IAB node to apply a time difference parameter for over-the-air synchronization in multiple alignment types, e.g., T _delta And/or N _delta . For example, a time difference parameter for Over The Air (OTA) synchronization in an IAB network may be received from a parent IAB node, and an IAB node receiving the time difference parameter may adjust transmission or reception of the IAB node based on the time difference parameter for one of a plurality of types of alignment at the IAB node and/or the parent IAB node. The IAB node may apply a time difference parameter for one of a number of potential types of alignment at the IAB. The first type of alignment (which may be referred to as case 1 alignment, for example) may include downlink transmission timing alignment across each IAB node of the IAB network. A second type of alignment, which may be referred to as a case 6 alignment, for example, may be between an uplink transmission at an IAB mobile terminal (IAB-MT) of a child IAB node and a downlink transmission at an IAB distributed unit (IAB-DU) of the child IAB node. A third type of alignment (which may be referred to as a case 7 alignment, for example) may be between downlink reception at the IAB-MT of the sub-IAB node and uplink reception at the IAB-DU of the sub-IAB node.

The various configurations are described below in connection with the detailed description set forth in the drawings, and are 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, the concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Aspects of a telecommunications system are presented with reference to various apparatus and methods. These apparatus and methods are described in the following detailed description 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 upon the particular application and design constraints imposed on the overall system.

For example, an element, or any portion of an element, or any combination of elements, may be implemented as a "processing system" that includes 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, system on a chip (SoC), baseband processors, field Programmable Gate Arrays (FPGAs), programmable Logic Devices (PLDs), state machines, gating logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors in the processing system may execute the software. Software should be construed broadly to mean instructions, instruction sets, code segments, program code, programs, subroutines, software components, applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Accordingly, in one or more example embodiments, the described functionality may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored or encoded on a computer-readable medium as one or more instructions or code. Computer readable media includes computer storage media. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can 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 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.

Although aspects, implementations, and/or use cases have been described herein by way of illustration of some examples, additional or different aspects, implementations, and/or use cases may occur in many different arrangements and scenarios. Aspects, implementations, and/or use cases described herein may be implemented across many different platform types, devices, systems, shapes, sizes, package arrangements. For example, aspects, implementations, and/or use cases may result from integrated chip implementations and other non-module component based devices (e.g., end user equipment, vehicles, communication devices, computing devices, industrial devices, retail/purchase devices, medical devices, artificial Intelligence (AI) enabled devices, etc.). While some examples may or may not be specific to use cases or applications, there may be a wide range of applicability of the described examples. Aspects, implementations, and/or use cases may range from chip-level or modular components to non-modular, non-chip-level implementations, and further to an aggregate, distributed, or Original Equipment Manufacturer (OEM) device or system incorporating one or more techniques herein. In some practical arrangements, devices incorporating the described aspects and features may also include additional components and features for implementation and implementation of the claimed and described aspects. For example, the transmission and reception of wireless signals necessarily includes a plurality of components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders/adders, etc.). The techniques described herein may be implemented in various devices, chip-level components, systems, distributed arrangements, aggregated or disassembled components, end-user devices, and the like having different sizes, shapes, and configurations.

Fig. 1 is a diagram illustrating an example of a wireless communication system and an access network 100. The wireless communication system and access network 100 may include an Integrated Access and Backhaul (IAB) network including a plurality of cells that communicate with one another to provide the access network and backhaul network to a core network such as core network 190 or Evolved Packet Core (EPC) 160. The core network 190 may be a 5G core (5 GC) core network that supports New Radio (NR) communications or another type of core network. The IAB network may include one or more IAB nodes 103. The IAB node may exchange communications with other IAB nodes 103, with base stations 102 or 180, and/or with UEs 104.

In some aspects, the IAB node 103 may include a time increment component 198 and/or a time increment indication component 199. The time increment component 198 may be configured to receive a time difference parameter from a parent IAB node for over-the-air (OTA) synchronization in an IAB network and adjust the sending or receiving of the IAB node based on the time difference parameter for one of a plurality of types of alignment at the IAB node and/or the parent IAB node. The time increment indication component may be configured to, for example, send to the child IAB node a time difference parameter for OTA synchronization in the IAB network that is applicable to the child IAB node and/or one of a plurality of types of alignment at the IAB node. The first type of alignment (which may be referred to as case 1 alignment, for example) may include downlink transmission timing alignment across each IAB node of the IAB network. A second type of alignment, which may be referred to as a case 6 alignment, for example, may be between an uplink transmission at an IAB mobile terminal (IAB-MT) of a child IAB node and a downlink transmission at an IAB distributed unit (IAB-DU) of the child IAB node. A third type of alignment (which may be referred to as a case 7 alignment, for example) may be between downlink reception at the IAB-MT of the sub-IAB node and uplink reception at the IAB-DU of the sub-IAB node. In some aspects, the IAB node may include both a time increment component 198 and/or a time increment indication component 199 in that the IAB node may perform some aspects of wireless communication as a parent IAB node and may perform other aspects as a child IAB node, e.g., the IAB node may have a parent IAB node and a child IAB node. Although examples in the following description may focus on 5G NR, the concepts described herein may be applicable to other similar fields, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

Wireless communication systems (also known as Wireless Wide Area Networks (WWANs)). The base station 102 shown in fig. 1 may support macro cells (high power cellular base stations) and/or small cells (low power cellular base stations). The macrocell includes a base station. Small cells include femto cells, pico cells, and micro cells.

A base station 102 configured for 4G LTE, commonly referred to as evolved Universal Mobile Telecommunications System (UMTS) terrestrial radio access network (E-UTRAN), may interface with the EPC 160 over a first backhaul link 132 (e.g., an S1 interface). A base station 102 configured for 5G NR, collectively referred to as a next generation RAN (NG-RAN), may interface with a core network 190 over a second backhaul link 184. Base station 102 may perform, among other functions, one or more of the following functions: transmission of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio Access Network (RAN) sharing, multimedia Broadcast Multicast Services (MBMS), user and device tracking, RAN Information Management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (e.g., through the EPC 160 or the core network 190) through a third backhaul link 134 (e.g., an X2 interface). The first backhaul link 132, the second backhaul link 184 (e.g., an Xn interface), and the third backhaul link 134 may be wired or wireless.

In some aspects, the base station 102 or 180 may be referred to as a RAN and may include an aggregated or disassembled component. As an example of a split RAN, a base station may include a Central Unit (CU) 111, one or more Distributed Units (DUs) 105, and/or one or more Remote Units (RUs) 109, as shown in fig. 1. The RAN may depolymerize with the split between RU 109 and the aggregated CU/DUs. The RAN may depolymerize with the split between CU 111, DU 105 and RU 109. The RAN may depolymerize with the split between CU 111 and the aggregated DU/RU. CU 111 and one or more DUs 105 may be connected via an F1 interface. The DU 105 and RU 109 may be connected via a forward interface. The connection between CU 111 and DU 105 may be referred to as mid-range, and the connection between DU 105 and RU 109 may be referred to as forward range. The connection between CU 111 and the core network may be referred to as backhaul. The RAN may be based on a functional split between various components of the RAN (e.g., between CUs 111, DUs 105, or RUs 109). CU 111 may be configured to perform one or more aspects of the wireless communication protocol, e.g., to process one or more layers of the protocol stack, and DU may be configured to process other aspects of the wireless communication protocol, e.g., other layers of the protocol stack. In different implementations, the splitting between the layers handled by CU 111 and the layers handled by DUs may occur at different layers of the protocol stack. As one non-limiting example, the DU 105 may provide a logical node to host at least a portion of a Radio Link Control (RLC), medium Access Control (MAC), and Physical (PHY) layers based on a functional split. An RU may provide a logical node configured to host at least a portion of a PHY layer and Radio Frequency (RF) processing. CU 111 may host higher layer functions, e.g., above the RLC layer, such as a Service Data Adaptation Protocol (SDAP) layer, a Packet Data Convergence Protocol (PDCP) layer. In other implementations, the split between layer functions provided by a CU, DU, or RU may be different.

The access network may include one or more Integrated Access and Backhaul (IAB) nodes 103 that exchange wireless communications with UEs 104 or other IAB nodes 103 to provide access and backhaul to the core network, e.g., as described in more detail in connection with fig. 4-6. In an IAB network of multiple IAB nodes, an anchor node may be referred to as an IAB donor. The IAB donor may be a base station 102 or 180 that provides access to the core network 190 or EPC 160 and/or control of one or more IAB nodes 103. The IAB donor may include CU 111 and DU 105. The IAB node 103 may include a DU 105 and a Mobile Terminal (MT). The DU 105 of the IAB node 103 may operate as a parent node and the MT may operate as a child node.

The base station 102 may communicate wirelessly with the UE 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, the 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 comprising both small cells and macro cells may be referred to as a heterogeneous network. The heterogeneous network may also include home evolved node B (eNB) (HeNB) and the HeNB may provide services to a restricted group called 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 a reverse link) transmissions from the UE 104 to the base station 102 and/or Downlink (DL) (also referred to as a forward link) transmissions from the base station 102 to the UE 104. Communication link 120 may use multiple-input multiple-output (MIMO) antenna techniques including spatial multiplexing, beamforming, and/or transmit diversity. The communication link may be through one or more carriers. The base station 102/UE 104 may use a spectrum of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc.) bandwidth per carrier allocated in carrier aggregation for up to yxmhz (x component carriers) total for transmission in each direction. The carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than 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).

Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL WWAN spectrum. The D2D communication link 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). D2D communication may be through a variety of wireless D2D communication systems such as, for example, wiMedia, bluetooth, zigBee, wi-Fi, LTE, or NR based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard.

Some examples of side-link communications may include vehicle-based communication devices that may communicate from and/or with vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I) (e.g., from vehicle-based communication devices to road infrastructure nodes, such as roadside units (RSUs)), vehicle-to-network (V2N) (e.g., from vehicle-based communication devices to one or more network nodes, such as base stations), vehicle-to-pedestrians (V2P), cellular vehicle-to-everything (C-V2X), and/or combinations thereof, which may be collectively referred to as vehicle-to-everything (V2X) communications. The side-link communication may be based on V2X or other D2D communication, such as proximity services (Pro Se), etc. In addition to the UE, the side-uplink communications may also be transmitted and received by other transmitting and receiving devices, such as a roadside unit (RSU) 107, and the like.

The wireless communication system may also include a Wi-Fi Access Point (AP) 150 that communicates with Wi-Fi Stations (STAs) 152 via a communication link 154 in, for example, a 5GHz unlicensed spectrum or the like. When communicating in the unlicensed spectrum, STA 152/AP 150 may perform Clear Channel Assessment (CCA) prior to communication to determine whether a channel is available.

The small cell 102' may operate in licensed and/or unlicensed spectrum. When operating in unlicensed spectrum, the small cell 102' may employ NR and use the same unlicensed spectrum (e.g., 5GHz, etc.) as used by the Wi-Fi AP 150. Small cells 102' employing NRs in unlicensed spectrum may improve access network coverage and/or increase access network capacity.

The electromagnetic spectrum is generally subdivided into various categories, bands, channels, etc., based on frequency/wavelength. In 5G NR, two initial operating bands have been identified as frequency range names FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). Although a portion of FR1 is greater than 6GHz, FR1 is often (interchangeably) referred to as the "below 6GHz" band in various documents and articles. Similar naming problems sometimes occur with respect to FR2, which is commonly (interchangeably) referred to in documents and articles as the "millimeter wave" band, although it is different from the Extremely High Frequency (EHF) band (30 GHz-300 GHz) identified by the International Telecommunications Union (ITU) as the "millimeter wave" band.

The frequency between FR1 and FR2 is commonly referred to as the mid-band frequency. Recent 5G NR studies have identified the operating band of these mid-band frequencies as frequency range designation FR3 (7.125 GHz-24.25 GHz). The frequency band falling within FR3 may inherit FR1 characteristics and/or FR2 characteristics, and thus may effectively extend the characteristics of FR1 and/or FR2 to mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operation above 52.6 GHz. For example, three higher operating bands have been identified as frequency range names FR4a or FR4-1 (52.6 GHz-71 GHz), FR4 (52.6 GHz-114.25 GHz) and FR5 (114.25 GHz-300 GHz). Each of these higher frequency bands falls within the EHF frequency band.

In view of the above, unless specifically stated otherwise, it should be understood that if the term is used herein, "below 6GHz" or the like may broadly represent frequencies that may be less than 6GHz, frequencies that may be within FR1, or may include mid-band frequencies. Furthermore, unless specifically stated otherwise, it should be understood that the term "millimeter wave" or the like, if used herein, may broadly represent frequencies that may include mid-band frequencies, frequencies that may be within FR2, FR4-a or FR4-1 and/or FR5, or may be within the EHF band.

Base station 102, whether small cell 102' or a large cell (e.g., macro base station), may include and/or be referred to as an eNB, a gndeb (gNB), or another type of base station. Some base stations (such as the gNB 180) may operate in the legacy below 6GHz spectrum, in mmW frequencies, and/or near mmW frequencies to communicate with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as a mmW base station. Extremely High Frequency (EHF) is a part of the RF in the electromagnetic spectrum. EHF has a range of 30GHz to 300GHz and a wavelength between 1 millimeter and 10 millimeters. The radio waves in the frequency band may be referred to as mmW waves. The near mmW may extend down to a frequency of 3GHz with a wavelength of 100 mm. The ultra-high frequency (SHF) band extends between 3GHz and 30GHz, also known as centimeter waves. Communications using the mmW/near mmW Radio Frequency (RF) band (e.g., 3GHz-300 GHz) have extremely high path loss and short distances. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for extremely high 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.

The base station 180 may transmit the beamformed signals to the UE 104 in one or more transmit directions 182'. The UE 104 may receive the beamformed signals from the base station 180 in one or more receive directions 182 ". The UE 104 may also transmit the beamformed signals in one or more transmit directions to the base station 180. The base station 180 may receive the beamformed signals from the UEs 104 in one or more directions. The base station 180/UE 104 may perform beam training to determine the best reception and transmission direction for each of the base station 180/UE 104. The transmit direction and the receive direction for the base station 180 may be the same or may be different. The transmit direction and the receive direction for the UE 104 may be the same or may be different.

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.MME 162 may communicate 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, MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are communicated through the serving gateway 166, which serving gateway 166 itself is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation as well as other functions. The PDN gateway 172 and BM-SC 170 are connected to an IP service 176.IP services 176 may include the internet, intranets, IP Multimedia Subsystem (IMS), PS streaming services, and/or other IP services. The BM-SC 170 may provide functions for MBMS user service provision and delivery. The BM-SC 170 may be used as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within a Public Land Mobile Network (PLMN), and may be used to schedule MBMS transmissions. The MBMS gateway 168 may be used to distribute MBMS traffic to base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting charging information related to eMBMS.

The core network 190 may include access and mobility management functions (AMFs) 192, other AMFs 193, session Management Functions (SMFs) 194, and User Plane Functions (UPFs) 195. The AMF 192 may communicate with a Universal data management Unit (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. In general, AMF 192 provides QoS flows and session management. All user Internet Protocol (IP) packets are transmitted through UPF 195. The UPF 195 provides UE IP address assignment as well as other functions. The UPF 195 is connected to an IP service 197.IP services 197 may include internet, intranet, IP Multimedia Subsystem (IMS), packet Switched (PS) streaming services, and/or other IP services.

A base station may include and/or be referred to as a gNB, a node B, eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a Basic Service Set (BSS), an Extended Service Set (ESS), a Transmit Receive 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 UEs 104 include a cellular telephone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop, a Personal Digital Assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electricity meter, an air pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similarly functioning device. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meters, air pumps, ovens, vehicles, cardiac monitors, 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 communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handheld device, user agent, mobile client, or some other suitable terminology. In some scenarios, the term UE may also apply to one or more companion devices, such as companion devices in a device constellation arrangement. One or more of these devices may access the network together and/or individually.

Deployment of a communication system, such as a 5G New Radio (NR) system, may be arranged in a variety of ways with various components or parts. In a 5G NR system or network, network nodes, network entities, mobile elements of a network, radio Access Network (RAN) nodes, core network nodes, network elements, or network devices, such as a Base Station (BS) or one or more units (or one or more components) performing base station functions, may be implemented in an aggregated or decomposed architecture. For example, BSs, such as Node BS (NB), evolved NB (eNB), NR BS, 5G NB, access Points (APs), transmission and Reception Points (TRP), cells, or the like, may be implemented as an aggregated base station (also referred to as a standalone BS or a monolithic BS) or a decomposed base station.

The aggregated base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. An decomposed base station may be configured to utilize a protocol stack that is physically or logically distributed between two or more units, such as one or more central or Centralized Units (CUs), one or more Distributed Units (DUs), or one or more Radio Units (RUs). In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed among one or more other RAN nodes. A DU may be implemented to communicate with one or more RUs. Each of the CUs, DUs, and RUs may also be implemented as virtual units, i.e., virtual Central Units (VCUs), virtual Distributed Units (VDUs), or Virtual Radio Units (VRUs).

Base station type operation or network design may take into account the aggregate nature of the base station functions. For example, the split base station may be utilized in an Integrated Access Backhaul (IAB) network, an open radio access network (O-RAN, such as a network configuration sponsored by the O-RAN alliance), or a virtual radio access network (vRAN, also referred to as a cloud radio access network (C-RAN)). The decomposition may include assigning functions across two or more units at various physical locations, and virtually assigning functions for at least one unit, which may enable flexibility in network design. The individual units of the split base station or the split RAN architecture may be configured for wired or wireless communication with at least one other unit.

Fig. 15 shows a diagram illustrating an example split base station 1500 architecture. The split base station 1500 architecture may include one or more Central Units (CUs) 1510 that may communicate directly with the core network 1520 via a backhaul link or indirectly with the core network 1520 through one or more split base station units, such as a near real-time (near RT) RAN Intelligent Controller (RIC) 1525 via an E2 link, or a non-real-time (non RT) RIC 1515 associated with a Service Management and Orchestration (SMO) framework 1505, or both. CU 1510 can communicate with one or more Distributed Units (DUs) 1530 via a corresponding mid-range link, such as an F1 interface. The DU 1530 may communicate with one or more Radio Units (RUs) 1540 via a corresponding forward link. RU 1540 may communicate with corresponding UEs 104 via one or more Radio Frequency (RF) access links. In some implementations, the UE 104 may be served by multiple RUs 1540 simultaneously.

Each of these units (i.e., CU 1510, DU 1530, RU 1540) and near RT RIC 1525, non-RT RIC 1515, and SMO framework 1505) may include or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively referred to as signals) via wired or wireless transmission media. Each of the units or an associated processor or controller providing instructions to a communication interface of the unit may be configured to communicate with one or more of the other units via a transmission medium. For example, a unit may include a wired interface configured to receive signals over a wired transmission medium or to transmit signals to one or more of the other units. Additionally, a unit may include a wireless interface that may include a receiver, transmitter, or transceiver (such as a Radio Frequency (RF) transceiver) configured to receive signals over a wireless transmission medium or transmit signals to one or more of the other units, or both.

In some aspects, CU 1510 may host one or more higher layer control functions. Such control functions may include Radio Resource Control (RRC), packet Data Convergence Protocol (PDCP), service Data Adaptation Protocol (SDAP), etc. Each control function may be implemented with an interface configured to communicate signals with other control functions hosted by CU 1510. CU 1510 may be configured to handle user plane functions (i.e., central unit-user plane (CU-UP)), control plane functions (i.e., central unit-control plane (CU-CP)), or a combination thereof. In some implementations, CU 1510 can be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit may communicate bi-directionally with the CU-CP unit via an interface (e.g., via an E1 interface when implemented in an O-RAN configuration). CU 1510 can be implemented to communicate with DU 1530 for network control and signaling, if necessary.

The DU 1530 may correspond to a logic unit that includes one or more base station functions to control the operation of the one or more RUs 1540. In some aspects, the DU 1530 may host one or more of the Radio Link Control (RLC) layer, medium Access Control (MAC) layer, and one or more high Physical (PHY) layers, such as modules for Forward Error Correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc., at least in part according to a functional split, such as a functional split defined by the third generation partnership project (3 GPP). In some aspects, the DU 1530 may also host one or more lower PHY layers. Each layer (or module) may be implemented with interfaces configured to communicate signals with other layers (and modules) hosted by the DU 1530 or control functions hosted by the CU 1510.

Lower layer functions may be implemented by one or more RUs 1540. In some deployments, RU 1540 controlled by DU 1530 may correspond to a logical node hosting RF processing functions or lower PHY layer functions (e.g., performing Fast Fourier Transform (FFT), inverse FFT (ift), digital beamforming, physical Random Access Channel (PRACH) extraction and filtering, etc.), or both, based at least in part on a functional split (such as a lower layer functional split). In such an architecture, RU 1540 may be implemented to handle over-the-air (OTA) communications with one or more UEs 104. In some implementations, the real-time and non-real-time aspects of control and user plane communications with RU 1540 may be controlled by the corresponding DU 230. In some scenarios, this configuration may enable the DUs 1530 and CUs 1510 to be implemented in a cloud-based RAN architecture (such as a vRAN architecture).

SMO framework 1505 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, SMO framework 1505 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operation and maintenance interface (such as an O1 interface). For virtualized network elements, SMO framework 1505 may be configured to interact with a cloud computing platform, such as an open cloud (O-enclosed) 1590, to perform network element lifecycle management (e.g., to instantiate virtualized network elements) via a cloud computing platform interface, such as an O2 interface. Such virtualized network elements may include, but are not limited to, CU 1510, DU 1530, RU 1540, and near RT RIC 1525. In some implementations, SMO framework 1505 may communicate with hardware aspects of the 4G RAN, such as open eNB (O-eNB) 1511, via an O1 interface. Additionally, in some implementations, SMO framework 1505 may communicate directly with one or more RUs 1540 via an O1 interface. SMO framework 1505 may also include a non-RT RIC 1515 configured to support the functionality of SMO framework 1505.

The non-RT RIC 1515 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence/machine learning (AI/ML) workflows (including model training and updating), or policy-based guidance of applications/features in the near-RT RIC 1525. The non-RT RIC 1515 may be coupled to or in communication with the near-RT RIC 1525 (e.g., via an A1 interface). Near RT RIC 1525 may be configured to include logic functions that enable near real-time control and optimization of RAN elements and resources via data collection and actions over interfaces (e.g., via E2 interfaces) connecting one or more CUs 1510, one or more DUs 1530, or both, and an O-eNB with near RT RIC 1525.

In some implementations, to generate the AI/ML model to be deployed in the near RT RIC 1525, the non-RT RIC 1515 may receive parameters or external rich information from an external server. Such information may be utilized by the near RT RIC 1525 and may be received at SMO framework 1505 or non-RT RIC 1515 from a non-network data source or network function. In some examples, the non-RT RIC 1515 or near-RT RIC 1525 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 1515 may monitor long-term trends and patterns of performance and employ AI/ML models to perform corrective actions through SMO framework 1505 (e.g., via reconfiguration of O1) or via creation of RAN management policies (such as A1 policies).

Fig. 2A is a diagram 200 illustrating an example of a first subframe within a 5G/NR frame structure. Fig. 2B is a diagram 230 illustrating an example of DL channels within a 5G/NR subframe. Fig. 2C is a diagram 250 illustrating an example of a second subframe within a 5G/NR frame structure. Fig. 2D is a diagram 280 illustrating an example of UL channels within a 5G/NR subframe. The 5G/NR frame structure may be Frequency Division Duplex (FDD) in which subframes within a subcarrier set are dedicated to DL or UL for a particular subcarrier set (carrier system bandwidth), or Time Division Duplex (TDD) in which subframes within a subcarrier set are dedicated to both DL and UL for a particular subcarrier set (carrier system bandwidth). In the example provided by fig. 2A, 2C, the 5G/NR frame structure is assumed to be TDD, with subframe 4 configured with slot format 28 (most of which are DL), where D is DL, U is UL, and X is flexible for use between DL/UL, and subframe 3 configured with slot format 34 (most of which are UL). Although subframes 3, 4 are shown as having slot formats 34, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. The slot formats 0, 1 are full DL, full UL, respectively. Other slot formats 2-61 include a mix of DL, UL and flexible symbols. The UE is configured with a slot format (dynamically configured by DL Control Information (DCI) or semi-statically/statically configured by Radio Resource Control (RRC) signaling) through a received Slot Format Indicator (SFI). Note that the following description also applies to the 5G/NR frame structure of TDD.

Fig. 2A-2D illustrate frame structures, and aspects of the present disclosure may be applicable to other wireless communication technologies, which may have different frame structures and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more slots. The 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. For a normal CP, each slot may include 14 symbols, and for an extended CP, each slot may include 12 symbols. The symbols on DL may be CP Orthogonal Frequency Division Multiplexing (OFDM) (CP-OFDM) symbols. The 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 known as single carrier frequency division multiple access (SC-FDMA) symbols) (for power limited scenarios; limited to single stream transmission). The number of slots within a subframe is based on CP and digital scheme (numerology). The digital scheme defines a subcarrier spacing (SCS) and in practice defines a symbol length/duration (which may be equal to 1/SCS).

μ	SCSΔf＝2 ^μ ·15[kHz]	Cyclic prefix
			0	15	General
1	30	General
			2	60	General, extension
3	120	General
			4	240	General

For a normal CP (14 symbols/slot), different digital schemes μ0 to 4 allow 1, 2, 4, 8 and 16 slots, respectively, per subframe. For extended CP, digital scheme 2 allows 4 slots per subframe. Accordingly, for the normal CP and digital scheme μ, there are 14 symbols/slot and 2 ^μ Each slot/subframe. The subcarrier spacing may be equal to 2 ^μ *15kHz, where μ is the digital schemes 0 through 4. Thus, the digital scheme μ=0 has a subcarrier spacing of 15kHz, and the digital scheme μ=4 has a subcarrier spacing of 240 kHz. The symbol length/duration is inversely related to the subcarrier spacing. Fig. 2A-2D provide examples of a normal CP (with 14 symbols per slot) and a digital scheme μ=2 (with 4 slots per subframe). The slot duration is 0.25ms, the subcarrier spacing is 60kHz and the symbol duration is approximately 16.67 mus. Within the frame set, there may be one or more different bandwidth portions (BWP) of the frequency division multiplexing (see fig. 2B). Each BWP may have a specific digital scheme and CP (normal or extended).

The resource grid may be used to represent a frame structure. Each slot includes Resource Blocks (RBs) (also referred to as Physical RBs (PRBs)), which include 12 consecutive subcarriers. The resource grid is divided into a plurality of Resource Elements (REs). The number of bits carried by each RE depends on the modulation scheme.

As shown in fig. 2A, some of the REs carry a reference (pilot) signal (RS) for the UE. The RSs may include demodulation RSs (DM-RSs) for channel estimation at the UE (indicated as R for one particular configuration, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RSs). The RSs may also include beam measurement RSs (BRSs), beam Refinement RSs (BRRSs), and phase tracking RSs (PT-RSs).

Fig. 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), each CCE including six RE groups (REGs), each REG including 12 consecutive REs in one OFDM symbol of an RB. The PDCCH within one BWP may be referred to as a control resource set (CORESET). The UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., common search space, UE-specific search space) during a PDCCH monitoring occasion on CORESET, wherein the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWP may be located at a larger and/or lower frequency across the channel bandwidth. The Primary Synchronization Signal (PSS) may be within symbol 2 of a particular subframe of a frame. 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. SSS is used by the UE to determine the physical layer cell identification group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE may determine a Physical Cell Identifier (PCI). Based on the PCI, the UE can determine the location of the DM-RS. A Physical Broadcast Channel (PBCH) carrying a Master Information Block (MIB) may be logically grouped with PSS and SSS to form a Synchronization Signal (SS)/PBCH block (also referred to as an SS block (SSB)). The MIB provides the number of RBs in the system bandwidth and a System Frame Number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information such as System Information Blocks (SIBs) that are not transmitted over the PBCH, and paging messages.

As shown in fig. 2C, some of the REs carry DM-RS for channel estimation at the base station (indicated as R for one particular configuration, but other DM-RS configurations are possible). The UE may transmit DM-RS for a Physical Uplink Control Channel (PUCCH) and DM-RS for a Physical Uplink Shared Channel (PUSCH). PUSCH DM-RS may be transmitted in the previous or two symbols of PUSCH. The PUCCH DM-RS may be transmitted in different configurations according to whether a short PUCCH or a long PUCCH is transmitted and according to a specific PUCCH format used. The UE may transmit a Sounding Reference Signal (SRS). The SRS may be transmitted in the last symbol of the subframe. The SRS may have a comb structure, and the UE may transmit the SRS on 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.

Fig. 2D shows examples of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries Uplink Control Information (UCI) such as a scheduling request, a Channel Quality Indicator (CQI), a Precoding Matrix Indicator (PMI), a Rank Indicator (RI), and hybrid automatic repeat request (HARQ) Acknowledgement (ACK) (HARQ-ACK) feedback (i.e., one or more HARQ ACK bits indicating one or more ACKs and/or Negative ACKs (NACKs)). PUSCH carries data and may additionally be used to carry Buffer Status Reports (BSR), power Headroom Reports (PHR), and/or UCI.

Fig. 3 is a block diagram of an IAB node 310 in an access network in communication with a UE 350. In DL, IP packets from EPC 160 or core network 190 may be provided to controller/processor 375. Controller/processor 375 implements layer 3 and/or layer 2 functionality. Layer 3 includes a Radio Resource Control (RRC) layer and may be performed if the IAB node is a donor IAB node. Layer 2 includes a Service Data Adaptation Protocol (SDAP) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, and a Medium Access Control (MAC) layer. Controller/processor 375 provides: RRC layer functions associated with: broadcast of system information (e.g., MIB, SIB), 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 associated with: header compression/decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with: transmission of upper layer Packet Data Units (PDUs), error correction by ARQ, concatenation of RLC Service Data Units (SDUs), segmentation and reassembly, re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functions associated with: 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 by HARQ, priority handling, and logical channel prioritization.

The Transmit (TX) processor 316 and the Receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1, which includes a Physical (PHY) layer, may include error detection of a transmission channel, forward Error Correction (FEC) encoding/decoding of the transmission channel, interleaving, rate matching, mapping onto a physical channel, modulation/demodulation of the physical channel, and MIMO antenna processing. TX processor 316 processes the 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 encoded and modulated symbols may then be split 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 domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying the time domain OFDM symbol stream. The OFDM streams are spatially precoded to produce a plurality of spatial streams. The channel estimates from the channel estimator 374 may be used to determine the coding and modulation scheme and for spatial processing. The channel estimate may be derived from reference signals and/or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318 TX. Each transmitter 318TX may modulate an RF carrier with a respective spatial stream for transmission.

At the UE 350, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to a Receive (RX) processor 356.TX processor 368 and RX processor 356 implement layer 1 functions associated with various signal processing functions. RX processor 356 can perform spatial processing on the information to recover any spatial streams destined for UE 350. If multiple spatial streams are destined for the UE 350, they may be combined into a single OFDM symbol stream by the RX processor 356. 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, as well as the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the IAB node 310. These soft decisions may be based on channel estimates computed by channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the IAB node 310 on the physical channel. The data and control signals are then provided to a controller/processor 359 that implements layer 3 and layer 2 functions.

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

Similar to the functionality described in connection with DL transmissions by the IAB node 310, the controller/processor 359 provides: RRC layer functions associated with: system information (e.g., MIB, SIB) acquisition, RRC connection and measurement report; PDCP layer functions associated with: header compression/decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with: transmission of upper layer PDUs, error correction by ARQ, concatenation of RLC SDUs, segmentation and reassembly, re-segmentation of RLC data PDUs and re-ordering of RLC data PDUs; and MAC layer functions associated with: mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction by HARQ, priority handling and logical channel prioritization.

Channel estimates derived by channel estimator 358 from reference signals or feedback transmitted by IAB node 310 may be used by TX processor 368 to select appropriate coding and modulation schemes, as well as to facilitate spatial processing. The spatial streams generated by Tx processor 368 may be provided to different antenna 352 via separate transmitters 354 Tx. Each transmitter 354Tx may modulate an RF carrier with a corresponding spatial stream for transmission.

UL transmissions are handled at the IAB node 310 in a similar manner as described in connection with the receiver functionality at the UE 350. Each receiver 318Rx receives a signal through its corresponding antenna 320. Each receiver 318Rx recovers information modulated onto an RF carrier and provides the information to the Rx processor 370.

The controller/processor 375 may be associated with a memory 376 that stores program codes and data. Memory 376 may be referred to as a computer-readable medium. In the UL, controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from UE 350. If the IAB node is not a donor IAB node, the IP packets from the controller/processor 375 may be provided to the EPC 160 or the core network 190, e.g., via the donor IAB node. Controller/processor 375 is also responsible for error detection using ACK and/or NACK protocols to support HARQ operations.

At least one of TX processor 368, RX processor 356, and controller/processor 359 may be configured to perform aspects in conjunction with time increment component 198 and/or time increment indication component 199, e.g., as described in conjunction with fig. 1.

At least one of TX processor 316, RX processor 370, and controller/processor 375 may be configured to perform aspects in conjunction with time increment component 198 and/or time increment indication component 199, e.g., as described in conjunction with fig. 1.

Fig. 4 is a diagram illustrating an IAB network 400. The IAB network provides access network functions between AN Access Node (AN) and other ANs/UEs and backhaul network functions between ANs. The AN includes AN IAB-donor (which has a wired connection to the core network) and AN IAB node (which operates wirelessly and relays traffic to/from the IAB-donor through one or more AN hops). The IAB AN shares resources between access and backhaul. That is, resources used for access communication between the AN and the AN/UE are also used for backhaul communication between the ANs.

The IAB network 400 may include an anchor node (which may be referred to herein as an "IAB donor") 410 and an access node (which may be referred to herein as an "IAB node") 420. The IAB donor 410 may be a base station such as a gNB or an eNB and may perform functions for controlling the IAB network 400. The IAB node 420 may include an L2 relay node or the like. The IAB donor 410 and the IAB node 420 together share resources to provide an access network and a backhaul network to the core network 490. For example, resources may be shared between an access link and a backhaul link in an IAB network.

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

Each IAB node (e.g., including IAB donor 410 and each IAB node 420) may use the PCI value. The PCI value may be used as an identifier for the IAB donor 410 or IAB node 420. The PCI value may be used to determine a scrambling sequence to be applied to the physical signals and/or channels transmitted by a particular IAB node. For example, PSS and/or SSS transmitted by the respective IAB donor 410 or IAB node 420 may be scrambled using a scrambling sequence based on the PCI used by the respective IAB node.

Fig. 5 shows a second diagram illustrating an IAB network 500 and its components. The IAB network 500 includes an IAB donor 510 and IAB nodes 520a and 520b. The IAB node and IAB donor may provide a radio access link to the UEs 530a, 530b, 530 c.

The IAB donor 510 may be considered a 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 comprise, for example, a wired optical fiber. The IAB donor node 510 may provide connectivity to one or more IAB nodes 520 a. The IAB nodes 520a may each be referred to as child nodes of the IAB donor node 510. The IAB donor node 510 may also provide connectivity to one or more UEs 530a, which UEs 530a may be referred to as sub-UEs of the IAB donor 510. The IAB donor 510 may be connected to its child IAB node 520a via a backhaul link 560 and may be connected to the child UE 530a via an access link 570. The IAB node 520a, which is a child of the IAB node 510, may also have an IAB node 520b and/or a UE 530b, which are children. For example, the IAB node 520b may also be connected to a child node and/or a child UE. Fig. 5 shows that the IAB nodes 520b provide access links to UEs 530c, respectively.

The IAB donor 510 may include a Central Unit (CU) and a Distributed Unit (DU). The central unit CU may provide control for the IAB nodes 520a, 520b in the IAB network 500. For example, a CU may control the IAB network 500 through configuration. The CU may perform RRC/PDCP layer functions. The IAB donor 510 also includes a DU to perform scheduling. For example, the DU may schedule resources for communication by the sub-IAB node 520a and/or UE 530a of the IAB donor 510. The DUs hold Radio Link Control (RLC), medium Access Control (MAC), physical (PHY) layer functions.

The IAB nodes 520a, 520b may include Mobile Terminals (MT) and DUs. The IAB node is an L2 relay node. The MT of the IAB node 520a may operate as a scheduled node, similar to the DU scheduling UE 530a of a parent node (e.g., IAB donor 510). The MT of the IAB node 520b may operate as a scheduled node of the parent node 520 a. The DU may schedule the sub-IAB node 520b and the UE 530b of the IAB node 520 a. Since an IAB node may provide a connection to an IAB node, the IAB node in turn provides a connection for another IAB node. The mode of the parent IAB node including the DUs of the scheduled child IAB node/child UE may continue to more connections shown in fig. 5.

Fig. 6 is a diagram 600 illustrating RLC channels in an IAB network. As described above, the IAB network provides both access network functions and backhaul network functions. Depending on the access network functionality, the IAB network includes AN IAB donor with a CU 602 and a DU 604, and the IAB ANs 606a, 606b and 606c may communicate with other UEs 608a and 608b and/or MTs of other IAB ANs over AN access RLC channel. The IAB ANs 606a, 606b, and 606c may route traffic to other ANs (e.g., 606a, 606b, and 606 c) over a backhaul RLC channel according to backhaul network functions. The access RLC channel includes UE-to-DU/DU-to-UE carrying PDCP for RRC or Data Radio Bearers (DRBs) and MT-to-DU/DU-to-MT carrying PDCP for RRC (or DRBs). The backhaul RLC channel includes MT to DU/DU to MT carrying Backhaul Adaptation Protocol (BAP) messages for backhaul access traffic.

Fig. 7A, 7B, and 7C illustrate example aspects of different timing patterns for IAB communications. Fig. 7A illustrates a timing example 700 of downlink transmission timing alignment across IAB nodes 702 and 704. In some aspects, downlink transmission timing may be aligned across each IAB node in an IAB network. The downlink timing transmission alignment may be referred to as a "case 1" alignment or may be referred to by another name. Fig. 7A shows DL transmission 708 of a DU from an IAB node 702 aligned in time with DL transmission 706 of a DU from an IAB node 704. An uplink timing adjustment framework may be applied in which a child IAB node (e.g., IAB node 704) receives an uplink timing adjustment from a parent IAB node to apply to an uplink transmission to the parent IAB node (e.g., IAB node 702). Fig. 7B and 7C illustrate time diagrams 725 and 750, respectively, with time diagrams 725 and 750 illustrating aspects of additional timing modes that may be used, for example, to provide or improve duplex capability between an IAB-MT and an IAB DU of an IAB node. The additional timing modes may provide improved timing alignment between MTs and DUs for space division multiplexed IAB nodes, e.g., when the IAB nodes perform simultaneous (e.g., overlapping at least in part in time and/or frequency) IAB-MT downlink reception in one direction and IAB-DU uplink reception in the other direction and/or perform IAB-MT uplink transmission in one direction and IAB-DU downlink reception in the other direction.

Fig. 7B illustrates an example timing diagram 725 that illustrates a pattern or type of timing alignment of an uplink transmission timing of an IAB-MT of an IAB node (e.g., IAB node 704) with a downlink transmission timing of an IAB-DU of the IAB node, e.g., that facilitates simultaneous (e.g., at least partially overlapping in time) transmission by the IAB-MT (e.g., UL transmission 710) and the IAB-DU (e.g., DL transmission 706) at the IAB node (e.g., IAB node 704). The alignment pattern of transmission alignment between MT and DU with IAB node in fig. 7B may be referred to as "case 6" pair Ji Huoke to be referred to by another name. As shown in fig. 7B, the timing alignment may also include downlink transmission timing alignment (e.g., case 1 alignment) across the IAB nodes, as described in connection with fig. 7A.

Fig. 7C illustrates an example timing diagram 750 that illustrates a pattern or type of timing alignment of downlink receive timing of an IAB-MT of an IAB node (e.g., IAB node 704) with uplink receive timing alignment of an IAB-DU of an IAB node, e.g., that facilitates simultaneous (e.g., at least partially overlapping in time) reception by an IAB-MT (e.g., DL reception 716) and an IAB-DU (e.g., UL reception 714) at an IAB node (e.g., IAB node 704). The alignment pattern of the reception alignment between MT and DU with IAB node in fig. 7C may be referred to as "case 7" alignment or may be referred to as another name. As shown in fig. 7C, the timing alignment may also include downlink transmission timing alignment (e.g., case 1 alignment) across the IAB nodes, as described in connection with fig. 7A.

For an alignment mode (e.g., case 6) that aligns transmissions of MTs and DUs of an IAB node, the timing at a given IAB node may include the IAB node setting the IAB-MT transmission timing to the timing obtained for the downlink transmission of the node. For an alignment mode (e.g., case 7) that aligns reception of MTs and DUs of an IAB node, timing at a parent IAB node (e.g., as compared to a given IAB node used to transmit the alignment mode) may include obtaining an IAB-MT transmission timing based on a timing advance loop plus an offset from the parent IAB node. Aspects presented herein provide for timing alignment that also supports OTA synchronization between IAB nodes.

OTA synchronization provides a mechanism for an IAB node to set its downlink transmission timing based on OTA signals received from one or more parent IAB nodes. OTA synchronization enables the IAB nodes of the IAB network to synchronize with each other, e.g., to provide DL transmission alignment across the IAB nodes described in connection with fig. 7A, separate from independent synchronization sources such as Global Navigation Satellite Systems (GNSS). OTA synchronization is based on Timing Advance (TA) control for uplink transmissions and an additional offset (T) indicated by the parent IAB node _delta ) A kind of electronic device. In some examples, the parent IAB node may be in the MAC-CE Indicating TA and T to the child IAB node (e.g., to MT of the child IAB node) _delta 。

Fig. 8 illustrates an example timing diagram 800 that illustrates timing differences between uplink transmissions at a child IAB node 804 and uplink receptions at a parent IAB node relative to downlink transmission timing at the parent IAB node. The difference between the uplink reception and the downlink transmission corresponds to an increment (delta). Since the parent IAB node 802 and the child IAB node 804 operate in timing alignment between downlink transmissions of DUs from each IAB node, the transmission times are aligned, where Tx _D ＝Tx ^P _D Wherein the transmission time of the DU of IAB node 804 is Tx _D And the transmission time of DU of parent IAB node is Tx ^P _D . The timing advance may correspond to ta=2tp+Δ and Δ=ta-2 Tp, where Tp corresponds to the propagation time between the parent IAB node 802 and the child IAB node 804, as shown by the difference between the time for the DL TX 806 to end and the time for the receiving DL RX 808 at the IAB node 804 to end for the corresponding transmission from the parent IAB node 802. The same propagation time is shown between the end of an uplink transmission 810 from an IAB node 804 and the end of the reception 812 of the corresponding uplink transmission at the parent IAB node 802. In this example, tx _D ＝Rx _D -Tp＝Rx _D - (TA-delta)/2, wherein Rx _D Corresponding to downlink reception at the DU of the IAB node 804. Also tp=ta/2+t _delta So that T is _delta ＝-Δ/2＝(Rx ^P _U -Tx ^P _D ) 2, wherein Rx ^P _U Corresponding to the uplink receive time (e.g., 812) at the parent IAB node 802.

Also, if the IAB node is provided with an index T in the timing increment MAC CE from the serving cell _delta Then when N _TA /2+N _delta +T _delta ·G _step >At 0, the IAB node may assume (N _TA /2+N _delta +T _delta ·G _step )·T _c Is the time difference between the transmission of the DU of the signal from the serving cell and the reception of the signal by the IAB-MT. N may be obtained in a similar manner as UE in TAG containing serving cell _TA 。N _delta And G _step Can be determined as:

if the serving cell providing the timing increment MAC CE is operating in FR1, N _delta = -70528 and G _step ＝64，

If the serving cell providing the timing increment MAC CE is operating in FR2, N _delta = -17664 and G _step ＝32。

The IAB node may use the time difference to determine the DU transmission time.

If the IAB node operates based on the transmission timing alignment between the MT of the IAB node and the DU, e.g., as described in connection with fig. 7B (e.g., case 6), the IAB-MT sets its own uplink transmission timing to be aligned with the downlink transmission timing of the DU of the IAB node (e.g., which may be referred to as a co-located DU co-located with the MT of the IAB node). In this example, there is no uplink timing advance because the parent IAB node does not control the uplink transmission timing of the child IAB-MT and does not send a TA command. Without closed loop feedback in the TA command from the parent IAB node, the child IAB node may not reliably synchronize its IAB-DU downlink transmission timing (e.g., synchronize downlink transmission timing for all DUs in the IAB network as described in connection with fig. 7A) and the synchronization of the IAB node with other IAB nodes may experience drift.

In some aspects, the IAB node may use T _delta To assist in OTA synchronization and transmission timing alignment at the IAB node (e.g., as in fig. 7B) and/or reception timing alignment at the IAB node (e.g., as in fig. 7C). T (T) _delta Is a function of the offset (e.g., delta or difference) between the uplink receive timing and the downlink transmit timing at the parent node and captures the offset. When an IAB node operates in a mode of transmission timing alignment at the IAB node (e.g., alignment described in case 6 or fig. 7B), a parent IAB node may track the reception timing from the IAB node and its offset from the downlink transmission timing of the parent IAB node. The offset may be equal to the one-way propagation delay from the IAB node to the parent IAB node (e.g., because of the uplink transmission timing of the IAB node and the downlink of the IAB node in case 6)The path transmission timing is the same as shown for 710 and 706 in fig. 7B, which is also aligned with the downlink transmission timing of the parent IAB node based on the downlink transmission timing as shown for 706 and 708 in fig. 7A and 7B). The parent IAB node may send updated T to the child IAB node _delta The value, for example, if the parent IAB node determines that the timing offset between DL transmission and UL reception (UL reception based on signals from the child IAB node) changes by more than a threshold amount of time. sub-IAB node receives updated T _delta Value, and may adjust its downlink transmission timing to account for possible synchronization drift between the parent and child IAB nodes.

In some aspects, the IAB node may change between timing alignment modes, e.g., between a downlink transmission alignment of DUs across the IAB network (e.g., case 1) and a transmission timing alignment at a given IAB node (e.g., case 6) and/or a reception timing alignment at the IAB node (e.g., case 7). Since the IAB node may change between these three different timing alignment modes and possibly other timing alignment modes, for T from the parent IAB node _delta The indication and/or interpretation of the values may be different.

As an example, if the IAB-MT follows a downlink transmission timing alignment between DUs (e.g., case 1 alignment) without transmission alignment or reception alignment at the IAB node, the uplink signal of the IAB node will arrive at a first time reference with a first offset from the downlink transmission timing of the parent node. The first offset is configured or determined by the parent IAB node, e.g., based on its implementation choice. Conversely, if the IAB-MT is operating based on the transmission timing alignment at a given IAB node (e.g., case 6) and selects its own uplink transmission timing to align with its downlink transmission timing, then the IAB node's uplink signal will arrive at a second time reference with a second offset from the parent IAB node's downlink transmission timing. For example, the second offset is a function of the one-way propagation delay between the IAB node and the parent node. If the IAB node is operating based on the receive timing alignment at the IAB node (e.g., case 7), where the IAB-MT transmission timing of the node is obtained from the parent IAB node by the TA instructing the IAB-MT to adjust its uplink transmission timing, the uplink signal of the IAB node will arrive at the parent node at a third time with a third offset from the downlink transmission timing of the parent IAB node. The third offset is a function of the one-way propagation delay between the parent IAB node and its own parent node.

Aspects presented herein enable an IAB node to apply or maintain OTA synchronization when the IAB node applies one of a number of different types of timing alignment, such as case 1, case 6, or case 7.

In some aspects, there may be no T from sub-IAB node to sub-IAB node for modes involving transmission timing alignment at sub-IAB node (e.g., case 6) and/or modes involving reception timing alignment at sub-IAB node (e.g., case 7) _delta Is an indication of (a). If the IAB node receives T from the parent IAB node _delta The child IAB node may determine T _delta Associated with the downlink transmission timing across DUs (e.g., case 1) and corresponding to the first offset in the example above. IAB node can apply T _delta To synchronize its downlink transmission timing with the parent IAB node according to case 1, and not to synchronize T _delta Applied to alignment for case 6 or case 7.

Fig. 9 illustrates an example 900 communication flow between an IAB node 902 and a parent IAB node 904. At 906, the IAB node 902 operates based on one of a plurality of different timing alignment modes. For example, the IAB node 902 may operate based on any of a case 1 timing alignment of downlink transmissions between DUs (such as in fig. 7A), a case 6 timing alignment of transmissions at the IAB node (such as in fig. 7B, for example), and/or a case 7 timing alignment of reception at the IAB node (such as in fig. 7C, for example). At 908, IAB node 902 receives a time difference parameter T from parent IAB node 904 _delta . IAB node 902 determines T _delta Case 1 timing alignment for downlink transmission between DUs. At 912, IAB node 902 aligns application T for case 1 timing _delta To adjust downlink transmission timing of DUs of IAB node to be in communication with parent IAB node 904DU alignment. The IAB node 902 then sends a message with T-based _delta The timed downlink transmission 914 is adjusted to synchronize the alignment to the parent IAB node's downlink transmission 916. As a further aspect, if the IAB node is configured to operate based on case 1 timing alignment on a set of frequent resources, the IAB node may avoid drift and perform OTA synchronization, which may provide feedback from the parent IAB node to the IAB node to set and/or constrain the timing of the IAB node. As one example, the IAB node may be configured to operate based on a case 1 timing of at least every 100 ms. In other examples, the IAB node may be configured to operate based on a case 1 timing with a shorter frequency or with a longer frequency than 100ms (such as every 200ms, 300ms, 400ms, 500ms, 600ms, or 640 ms).

In some aspects, the IAB-MT transmission timing of an IAB node may be obtained from a TA command from a parent IAB node plus an offset from the parent node. The IAB node operating in the timing alignment according to case 7 can determine T _delta (for application in case 7 timing alignment) =t _delta (associated with case 1 alignment) +indicated offset.

In some aspects, T _delta May be indicated for various types of timing alignment at the IAB node. The parent IAB node may provide the T indicated by the indication to the child IAB node _delta Information of the association between the associated timing alignment type. For example, the indication may indicate whether T was measured when the parent node was operating in case 1 and the child node was not operating in case 6 _delta . The indication may indicate whether T is measured when the parent node is operating in case 7 and the child node is not operating in case 6 _delta . The indication may indicate whether T is measured while the child node is operating in case 6 _delta . The indication may help the IAB node determine to which T the IAB node should apply the received T _delta Is used for the timing alignment of the device.

In some aspects, a parent IAB node may provide a new T associated with transmission timing alignment (e.g., case 6) between MT and DU at the IAB node _delta And/or N _delta . FIG. 10 shows an exampleCommunication flow 1000 illustrates parent IAB node 1004 providing additional T to IAB node 1002 (e.g., which is a child of parent IAB node 1004) _delta And/or N _delta 1009, example. In some aspects, except for the first T applicable to case 1 _delta And/or N _delta 1008, may also configure and/or indicate additional T' s _delta And/or N _delta 1009. Additional T may be incorporated in MAC-CE and/or DCI _delta And/or N _delta 1009 signals the IAB node 1002. T alignable with case 1 _delta And/or N _delta 1008 separately indicate to the IAB node an additional T for case 6 timing alignment _delta And/or N _delta For example in a separate message. In other aspects, additional T's may be added _delta And/or N _delta 1009 with T aligned with the timing for case 1 _delta And/or N _delta 1008 together signal the IAB node 1002, e.g., in the same message.

In some aspects, the parent IAB node 1004 may indicate a T aligned relative to case 1 _delta And/or N _delta 1008, an additional offset value 1010. The additional offset 1010 may be configured other than to be aligned for the case T _delta And/or N _delta 1008, and may be an offset parameter associated with case 6 timing alignment. Relative to T _delta And/or N _delta 1008, which can be aligned with T for case 1 _delta And/or N _delta 1008 separately indicate to the IAB node 1002 an additional offset 1010 for case 6 timing alignment, e.g., in a separate message. In other aspects, the additional offset 1010 may be aligned with T for case 1 timing _delta And/or N _delta 1008 together signal the IAB node 1002, e.g., in the same message. An offset 1010 for case 6 timing alignment may be signaled to the IAB node 1002 in the MAC-CE and/or DCI.

At 1012, IAB node 1002 applies additional T _delta And/or N _delta 1009 or an offset 1010 for case 6 timing alignment to adjust the transmission timing of the MT/DU of the IAB node. Then IABNode 1002 sends a message with T-based _delta And/or N _delta 1009 or offset 1010 the timing of the adjusted downlink transmission 1014. In some aspects, at 1010, the IAB node 1002 may interpret the pair T _delta And/or N _delta 1009 or offset 1010 to indicate a switch from a different timing alignment mode to case 6 timing alignment. For example, at 1006, the IAB node 1002 may operate/perform case 1 or case 7 timing alignment in case 1 or case 7 timing alignment, and the IAB node 1002 may respond to the T-pair _delta And/or N _delta 1009 or reception of offset 1010 to switch to perform case 6 timing alignment. Although this example is described for case 6, in some aspects, additional T _delta And/or N _delta 1009 or offset 1010 may be associated with case 7 timing alignment. Thus, at 1014 and 1016, the IAB node 1002 may adjust the transmit or receive timing according to case 6 or case 7 timing alignment.

In some aspects, the same T may be used in different types of timing alignment _delta And/or N _delta Parameters. When the father IAB node indicates T _delta And/or N _delta The parent node may also indicate the type of timing alignment that the parameters apply. FIG. 11 illustrates an example communication flow 1100 that shows a parent IAB node 1104 providing T to an IAB node 1102 (e.g., that is a child node of the parent IAB node 1104) _delta And/or N _delta 1108, an example of a metal mold. Indication T _delta And/or N _delta The transmission of 1108 may also indicate a type of timing alignment associated with the indicated parameter, e.g., a type of timing alignment upon which the parameter is based and/or a type of timing alignment the parameter is intended to be applied. T may be signaled to IAB node 1102 in MAC-CE and/or DCI _delta And/or N _delta 1108. In some aspects, the flag (e.g., carrying T _delta And/or N _delta One or more bit flags in the message of 1108) may indicate one of different types of timing alignment (e.g., case 1, case 6, and/or case 7). The inclusion of the tag itself and/or a particular value of the tag may indicate, for example, T _delta And/or N _delta 1108 and giveCase 6 transmission timing alignment at the fixed IAB node is associated. Similarly, the inclusion of the tag itself and/or a particular value of the tag may indicate, for example, T _delta And/or N _delta 1108 is associated with case 7 receive timing alignment at the IAB node. If the flag indicates between case 1 and case 6, the flag may comprise a single bit. As an example, "1" may indicate case 6 and "0" may indicate case 1, or conversely, "0" indicates case 6 and "1" indicates case 1. If the flag indicates between case 1, case 6, and case 7 or other timing alignment cases, the criteria may include two or more bits.

In some aspects, the resource on which the indication is sent may indicate an associated timing alignment type. The IAB node 1102 may infer or otherwise determine the information associated with T based on the resources of the message carrying the parameters _delta And/or N _delta 1108 associated timing alignment type. As an example, if the IAB node 1102 receives T on a time resource within a time offset before or after the resource in which case 1 or case 6 is employed _delta And/or N _delta 1108, T _delta And/or N _delta The time resources of 1108 may indicate an association with case 1 timing alignment or case 6 timing alignment, respectively. As another example, case 1 and case 6 timing alignment may be associated with separate spatial resources. The IAB-MT may use beam 1 when operating with case 1 (which may be associated with a multiplexing scenario such as TDM only) and with case 6 (which may be associated with a multiplexing scenario such as SDM-TX or (MT-TX) &Association of multiplexing scenario for DU-TX), beam 2 is used in operation, in which case if the IAB node 1102 (e.g., MT) receives T on a given beam _delta And/or N _delta 1108, the IAB node may associate it with the corresponding timing situation.

At 1112, the IAB node 1102 applies the received T for the indicated timing alignment type _delta And/or N _delta 1008 to adjust the transmit/receive timing of MT/DUs of the IAB node 1102, as shown at 1114 and 1116. In some aspects, at 1110, the IAB node 1102 may pair T _delta And/or N _delta The receipt of 1108 and the particular type of indication of timing alignment is interpreted as an indication of switching to perform the indicated type of timing alignment. For example, at 1106, the IAB node 1102 may operate/perform a first type of timing alignment in the first type of timing alignment and may switch to be aligned with T at 1110 _delta And/or N _delta 1108 are associated with different types of timing alignment.

Fig. 12 is a flow chart 1200 of a method of wireless communication. The method may be performed by an IAB node (e.g., IAB node 103, 310, 410, 420, 510, 520a, 520b, 704, 902, 1002, 1102; apparatus 1402; baseband unit 1404, which may include memory 376 and may be the entire IAB node 310 or a component of IAB node 310 such as TX processor 316, RX processor 370, and/or controller/processor 375). The method may enable the IAB node to apply a time difference parameter for over-the-air synchronization in multiple alignment types, e.g., T _delta And/or N _delta 。

At 1202, an IAB node receives a time difference parameter from a parent IAB node for over-the-air synchronization in an IAB network. Fig. 9, 10 and 11 illustrate examples of an IAB node receiving a time difference parameter from a parent IAB node. For example, the time difference parameter may include T _delta And/or N _delta For example as described in connection with fig. 9 or 11. For example T _delta May be based on the time difference between the uplink receive time and the downlink transmit time at the parent IAB node, as described in connection with fig. 8. The time difference parameter may correspond to an additional T _delta And/or N _delta 1009 or with T _delta And/or N _delta For example, as described in connection with fig. 10. In some aspects, the reception of the time difference parameter may be performed by the time difference parameter receiving component 1440 via the receiving component 1430 and/or the RF transceiver 1422 of the apparatus 1402 in fig. 14.

At 1204, the IAB adjusts the sending or receiving of the IAB nodes based on the time difference parameter for one of the plurality of types of IAB node alignment, e.g., to be between IAB nodes (as in case 1), at IAB nodes (as in case 6), andor alignment is provided at the parent IAB node (as in case 7). Various types of timing alignment may include: a first type of alignment (e.g., case 1) that includes downlink transmission timing alignment across each IAB node of an IAB network; a second type of alignment (e.g., case 6) between an uplink transmission at an IAB-MT of an IAB node and a downlink transmission at an IAB-DU of the IAB node; and a third type of alignment (e.g., case 7) between downlink reception at the IAB-MT of the IAB node and uplink reception at the IAB-DU of the IAB node. Adjustment of transmission or reception may be performed by timing alignment component 1442 of apparatus 1402 in fig. 14. For example, the IAB node may be based on a time difference parameter T _delta The downlink transmission timing is adjusted to align with the downlink transmission timing of other IAB nodes according to case 1. In other examples, the IAB node may adjust uplink transmission timing and/or DL transmission timing at the IAB node according to the case 6 alignment to provide alignment between UL and DL transmissions at the IAB node. In other examples, the IAB node may adjust the uplink or downlink receive timing to provide alignment between UL and DL reception according to the case 7 alignment.

In some aspects, the time difference parameter may correspond to T _delta And the IAB node may be T-based according to the first type of alignment _delta To adjust the downlink transmission time of the IAB node. For example, at 1202, for T _delta May indicate to the IAB node to apply the first type of alignment. FIG. 9 shows a method in which T _delta Examples associated with case 1 timing alignment.

In some aspects, the time difference parameter may correspond to an offset parameter indicated with a timing advance command for a third type of alignment, and the IAB node may calculate T from the offset parameter (e.g., and TA command) _delta And may adjust the calculated T based on a third type of alignment (e.g., case 7) _delta Is transmitted or received by the IAB node.

In some aspects, the indication of the time difference parameter received from the parent IAB node may be indicative of multiple typesAn association of one of the alignments of (a). For example, a first time difference parameter (T _delta And/or N _delta ) Can be aligned with the first type and a second time difference parameter (additional T _delta And/or N _delta 1009 or time offset 1010 to T _delta And/or N _delta ) And (5) associating. The IAB node may receive both the first time difference parameter and the second time difference parameter from the parent IAB node, e.g., as described in connection with the example in fig. 10. The IAB node may receive the first time difference parameter and the second time difference parameter in separate messages from the parent IAB node. The IAB node may receive the first time difference parameter and the second time difference parameter in the same message from the parent IAB node. A first time difference parameter (e.g., T _delta And/or N _delta 1008 A) may be associated with a first type of alignment and the second time difference parameter may be a time offset (from T) associated with a second type of alignment _delta And/or N _delta The offset 1010) of (2) is relative to the first time difference parameter. The IAB node may receive both the first time difference parameter and the second time difference parameter from the parent IAB node. The IAB node may receive the first time difference parameter and the second time difference parameter in separate messages from the parent IAB node. The IAB node may receive the first time difference parameter and the second time difference parameter in the same message from the parent IAB node.

In some aspects, the indication of the time difference parameter may include a flag corresponding to the type of alignment associated with the time difference parameter, e.g., as described in connection with the example in fig. 11. In some aspects, the resource in which the indication of the time difference parameter is received may indicate a type of alignment associated with the time difference parameter, e.g., as described in connection with the example in fig. 11.

Fig. 13 is a flow chart 1300 of a method of wireless communication. The method may be performed by a parent IAB node (e.g., IAB node 103, 310, 410, 420, 510, 520a, 520b, 702, 904, 1004, 1104; apparatus 1402; baseband unit 1404, which may include memory 376 and may be the entire IAB node 310 or a component of IAB node 310, such as TX processor 316, RX processor 370, and/or controller/processor 375)And (3) row. The method may enable the IAB node to apply a time difference parameter for over-the-air synchronization in multiple alignment types, e.g., T _delta And/or N _delta 。

At 1302, a parent IAB node transmits or receives communications with a child IAB node. The communication may be based on any of the aspects described in connection with fig. 4, 5, 6, 7, 9, 10, or 11. The communication may be based on one of a plurality of types of timing alignment. In some aspects, transmitting and receiving may be performed, for example, by the receiving component 1430 and the transmitting component 1434 of the apparatus 1402 in fig. 10.

At 1304, the parent IAB node transmits a time difference parameter for over-the-air synchronization in the IAB network that is applicable to one of a plurality of types of IAB node alignment, e.g., to provide alignment between IAB nodes (as in case 1), at an IAB node (as in case 6), and/or at the parent IAB node (as in case 7). Fig. 9, 10 and 11 show examples of a parent IAB node transmitting a time difference parameter from the parent IAB node. For example, the time difference parameter may include T _delta And/or N _delta For example as described in connection with fig. 9 or 11. For example T _delta May be based on the time difference between the uplink receive time and the downlink transmit time at the parent IAB node, as described in connection with fig. 8. The time difference parameter may correspond to an additional T _delta And/or N _delta 1009 or with T _delta And/or N _delta For example, as described in connection with fig. 10. In some aspects, the transmission of the time difference parameter may be performed by the time difference parameter indicator component 1444 via the transmit component 1434 and/or the RF transceiver 1422 of the apparatus 1402 in fig. 14.

Various types of timing alignment may include: a first type of alignment (e.g., case 1) that includes downlink transmission timing alignment across each IAB node of an IAB network; a second type of alignment (e.g., case 6) between an uplink transmission at an IAB-MT of an IAB node and a downlink transmission at an IAB-DU of the IAB node; and a third type of alignment (e.g., case 7) between downlink reception at the IAB-MT of the IAB node and uplink reception at the IAB-DU of the IAB node.

In some aspects, the time difference parameter may correspond to T _delta And may be associated with a first type of alignment. For example, at 1202, T _delta May indicate to the child IAB node to apply the first type of alignment. FIG. 9 shows a method in which T _delta Examples associated with case 1 timing alignment.

In some aspects, the time difference parameter may correspond to an offset parameter indicated with a timing advance command for a third type of alignment and used to calculate T from the offset parameter (e.g., and TA command) _delta And may adjust the T with the calculation based on a third type of alignment (e.g., case 7) _delta Associated with transmission or reception of IAB nodes.

In some aspects, the indication of the time difference parameter sent from the parent IAB node may indicate an association with one of a plurality of types of alignment. For example, a first time difference parameter (T _delta And/or N _delta ) May be associated with a first type of alignment and a second time difference parameter (additional T _delta And/or N _delta 1009 or with T _delta And/or N _delta The offset 1010) of (a) may be associated with a second type of alignment. The parent IAB node may send both the first time difference parameter and the second time difference parameter to the child IAB node, e.g., as described in connection with the example in fig. 10. The parent IAB node may receive the first time difference parameter and the second time difference parameter in separate messages to the child IAB nodes. The parent IAB node may send the first time difference parameter and the second time difference parameter in the same message to the child IAB node. A first time difference parameter (e.g., T _delta And/or N _delta 1008 A) may be associated with a first type of alignment and the second time difference parameter may be a time offset (from T) associated with a second type of alignment _delta And/or N _delta The offset 1010) of (a) is relative to the first time difference parameter. The parent IAB node may send both the first time difference parameter and the second time difference parameter to the child IAB node. Father IABThe node may send the first time difference parameter and the second time difference parameter to the child IAB node in separate messages. The parent IAB node may send the first time difference parameter and the second time difference parameter to the child IAB node in the same message.

In some aspects, the indication of the time difference parameter may include a flag corresponding to the type of alignment associated with the time difference parameter, e.g., as described in connection with the example in fig. 11. In some aspects, the resource in which the indication of the time difference parameter is transmitted may indicate a type of alignment associated with the time difference parameter, e.g., as described in connection with the example in fig. 11.

Fig. 14 is a diagram 1400 illustrating an example of a hardware implementation for the apparatus 1402. The apparatus 1402 may be an IAB node, a component of an IAB node, or may implement an IAB node functionality. The apparatus 1402 may correspond to an IAB node 103, 310, 420, 520a-b, 606a, 606b, 702, 704, 802, 804, 902, 904, 1002, 1004, 1102, or 1104. In some aspects, the apparatus may include a baseband unit 1404. The baseband unit 1404 may communicate with one or more UEs 104 via a cellular RF transceiver. The baseband unit 1404 may also communicate with one or more IAB nodes 103 via a cellular RF transceiver. The IAB node 103 may be a parent node of the device or may be a child node of the device. The baseband unit 1404 may include a computer readable medium/memory. The baseband unit 1404 is responsible for general processing, including the execution of software stored on a computer-readable medium/memory. The software, when executed by the baseband unit 1404, causes the baseband unit 1404 to perform the various functions described supra. The computer readable medium/memory can also be used for storing data that is manipulated by the baseband unit 1404 when executing software. The baseband unit 1404 further includes a receive component 1430, a communication manager 1432, and a transmit component 1434. The communications manager 1432 includes one or more illustrated components. The components within the communication manager 1432 may be stored in a computer-readable medium/memory and/or configured as hardware within the baseband unit 1404. The baseband unit 1404 may be a component of the IAB node 310 and may include a memory 376 and/or at least one of a TX processor 316, an RX processor 370, and a controller/processor 375.

The communication manager 1432 includes a time difference parameter receiving component 1440 configured to receive time difference parameters from a parent IAB node for over-the-air synchronization in an IAB network, e.g., as described in connection with 1202 in fig. 14. The communication manager 1432 includes a time difference parameter indicator component 1444 configured to indicate to the child IAB nodes time difference parameters for over-the-air synchronization in an IAB network, e.g., as described in connection with 1304 in fig. 13. The communication manager 1432 further includes a timing alignment component 1442 configured to adjust the sending or receiving of an IAB node based on a time difference parameter for one of a plurality of types of alignment at the IAB node and/or a parent IAB node, e.g., as described in connection with 1204 in fig. 14. The apparatus 1402 further comprises a receiving component 1430 and a transmitting component 1434 configured to transmit and receive communications with the child IAB node, e.g., as described in connection with 1302 in fig. 13.

The apparatus may include additional components to perform each of the blocks of the algorithm in the flowcharts of fig. 12 or 13 and/or aspects performed by the IAB node in any of fig. 9, 10, or 11. Accordingly, each block in the flow diagrams of fig. 12 or 13 and/or aspects performed by the IAB node in any of fig. 9, 10, or 11 may be performed by components, and the apparatus may include one or more of those components. A component may be one or more hardware components specifically configured to perform the process/algorithm, implemented by a processor configured to perform the process/algorithm, stored within a computer readable medium for implementation by a processor, or some combination thereof.

As shown, the apparatus 1402 may include various components configured for various functions. In one configuration, the apparatus 1402 (specifically, the baseband unit 1404) may include: means for receiving a time difference parameter from a parent IAB node for OTA synchronization in an IAB network; and means for adjusting transmission or reception of the IAB node based on the time difference parameter for one of the multiple types of alignment at the IAB node and/or the parent IAB node. The apparatus 1402 may further include: a unit for transmitting or receiving communications with the child IAB node; and means for transmitting a time difference parameter for over-the-air synchronization in the IAB network, the time difference parameter being for an application of one of a plurality of types of alignment at the sub-IAB node. In some aspects, apparatus 1402 may include means for performing the aspects of fig. 12 and 13, as apparatus 1402 may operate as a parent node of one or more child nodes and may operate as a child node of the parent node. These units may be one or more components of apparatus 1402 configured to perform the functions recited by these units. As described above, apparatus 1402 may include TX processor 316, RX processor 370, and controller/processor 375. Thus, in one configuration, the elements may be TX processor 316, RX processor 370, and controller/processor 375 configured to perform the functions recited by the elements.

It should be understood that the specific order or hierarchy of blocks in the processes/flowcharts disclosed is an illustration of example approaches. It should be appreciated that the particular order or hierarchy of blocks in the process/flow diagram may be rearranged based on design preferences. Furthermore, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

The previous 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 generic principles defined herein may be applied to other aspects. Thus, the claims are not to be limited to the aspects described herein, but are to be accorded the full scope consistent with the language claims. Unless explicitly stated to the contrary, reference to a singular element does not mean "one and only one" but "one or more". Terms such as "if", "when … …" and "at … …" do not mean an immediate time relationship or reaction. That is, these phrases (e.g., "when … …") do not mean that an action occurs in response to or immediately during the occurrence of the action, but rather only that an action will occur if a condition is met, but do not require specific or immediate time constraints 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. The term "some" refers to one or more unless specifically stated otherwise. 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", and "A, B, C or any combination thereof" include any combination of A, B and/or C, and may include multiple a, multiple B, or multiple C. Specifically, combinations such as "at least one of A, B or C", "A, B, or one or more of C", "at least one of A, B and C", "one or more of A, B and C", and "A, B, C or any combination thereof" may be a alone, B alone, C, A and B, A and C, B and C, or a and B and C, wherein any such combination may comprise one or more members of A, B or C. A collection should be interpreted as a collection of elements, where the number of elements is one or more. Thus, for a group of X, X will include one or more elements. If a first device receives data from or transmits data to a second device, the data may be received/transmitted directly between the first device and the second device or indirectly between the first device and the second device through a set of devices. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known to those of ordinary skill in the art or that are later come to be known are expressly incorporated herein by reference and are intended to be encompassed by the claims. Furthermore, the disclosures herein are not intended to be dedicated to the public, regardless of whether such disclosures are explicitly recited in the claims. The words "module," mechanism, "" element, "" device, "and the like may not be a substitute for the word" unit. Thus, no claim element is to be construed as a functional module unless the element is explicitly recited using the phrase "means for … …".

As used herein, the phrase "based on" should not be construed as a reference to a closed information set, one or more conditions, one or more factors, etc. In other words, unless specifically stated differently, the phrase "based on a" (where "a" may be information, conditions, factors, etc.) should be construed as "based at least on a".

The following aspects are merely illustrative and may be combined with other aspects or teachings described herein without limitation.

Aspect 1 is a method of wireless communication at an IAB node, comprising: receiving a time difference parameter from a parent IAB node for over-the-air synchronization in an IAB network; and adjusting transmission or reception of the IAB node based on the time difference parameter for one of a plurality of types of IAB node alignments.

In aspect 2, the method according to aspect 1, further comprising: the plurality of types of IAB node alignments include: including a first type of alignment of downlink transmission timing alignment across each IAB node of the IAB network, a second type of alignment between uplink transmissions at an IAB-MT of the IAB node and downlink transmissions at an IAB-DU of the IAB node, and a third type of alignment between downlink reception at the IAB-MT of the IAB node and uplink reception at the IAB-DU of the IAB node.

In aspect 3, the method according to aspect 1 or aspect 2, further comprising: the time difference parameter is associated with the first type of alignment and the third type of alignment.

In aspect 4, the method according to aspect 1 or aspect 2, further comprising: the time difference parameter corresponds to T based on a time difference between an uplink reception time and a downlink transmission time at the parent IAB node _delta And the IAB node is T-based according to the first type of alignment _delta To adjust the downlink transmission time of the IAB node.

In aspect 5, the method according to aspect 4, further comprising: for said T _delta Indicates to the IAB node to apply theA first type of alignment.

In aspect 6, the method according to aspect 1 or aspect 2, further comprising: the time difference parameter corresponds to an offset parameter indicated with a timing advance command for the third type of alignment, the method further comprising: calculating T from the offset parameter _delta And utilizing the T based on the third type of alignment _delta To adjust the sending or the receiving of the IAB node.

In aspect 7, the method according to any one of aspects 1 to 3, further comprising: the indication of the time difference parameter received from the parent IAB node indicates an association with one of the multiple types of IAB node alignments.

In aspect 8, the method of aspect 1 or aspect 7, further comprising: a first time difference parameter is associated with the first type of alignment and a second time difference parameter is associated with the second type of alignment.

In aspect 9, the method of aspect 8, further comprising: the IAB node receives both the first time difference parameter and the second time difference parameter from the parent IAB node.

In aspect 10, the method according to aspect 9, further comprising: the IAB node receives the first time difference parameter and the second time difference parameter in separate messages from the parent IAB node.

In aspect 11, the method according to aspect 9, further comprising: the IAB node receives the first time difference parameter and the second time difference parameter in the same message from the parent IAB node.

In aspect 12, the method of aspect 8, further comprising: the first time difference parameter is associated with the first type of alignment and the second time difference parameter is a time offset associated with the second type of alignment, the time offset being relative to the first time difference parameter.

In aspect 13, the method of aspect 8, further comprising: the IAB node receives both the first time difference parameter and the second time difference parameter from the parent IAB node.

In aspect 14, the method of aspect 13, further comprising: the IAB node receives the first time difference parameter and the second time difference parameter in separate messages from the parent IAB node.

In aspect 15, the method of aspect 13, further comprising: the IAB node receives the first time difference parameter and the second time difference parameter in the same message from the parent IAB node.

In aspect 16, the method according to any one of aspects 7-15, further comprising: the indication of the time difference parameter includes a flag corresponding to a type of alignment associated with the time difference parameter.

In aspect 17, the method of any one of aspects 7-16, further comprising: the resource in which the indication of the time difference parameter is received indicates a type of alignment associated with the time difference parameter.

Aspect 18 is an apparatus for wireless communication, comprising: a unit for performing the method according to any one of aspects 1-17.

In aspect 19, the apparatus of aspect 18, further comprising at least one antenna and a transceiver coupled to the at least one antenna.

Aspect 20 is an apparatus for wireless communication, comprising: a memory; and at least one processor coupled to the memory and configured to perform the method of any one of aspects 1-17 based at least in part on information stored in the memory.

In aspect 21, the apparatus of aspect 20, further comprising at least one of an antenna or a transceiver coupled to the at least one antenna and the at least one processor.

Aspect 22 is a non-transitory computer-readable medium storing computer-executable code, which when executed by a processor, causes the processor to perform the method according to any one of aspects 1-17.

Aspect 23 is a method of wireless communication at an IAB parent node, comprising: transmitting or receiving communication with an IAB node that is a child node of the parent IAB node; and sending a time difference parameter for over-the-air synchronization in the IAB network, the time difference parameter being applicable to one of a plurality of types of IAB node alignment.

In aspect 24, the method of aspect 23, further comprising: the plurality of types of IAB node alignments include: including a first type of alignment of downlink transmission timing alignment across each IAB node of the IAB network, a second type of alignment between uplink transmissions at an IAB-MT of the IAB node and downlink transmissions at an IAB-DU of the IAB node, and a third type of alignment between downlink reception at the IAB-MT of the IAB node and uplink reception at the IAB-DU of the IAB node.

In aspect 25, the method of aspect 23 or aspect 24, further comprising: the time difference parameter corresponds to T associated with the first type of alignment _delta The T is _delta Is based on a time difference between an uplink reception time and a downlink transmission time at the parent IAB node.

In aspect 26, the method of aspect 25, further comprising: for said T _delta Indicates to the IAB node to apply the first type of alignment.

In aspect 27, the method of aspect 23 or aspect 24, further comprising: an indication of the time difference parameter from the parent IAB node indicates an association with one of the multiple types of IAB node alignments.

In aspect 28, the method of aspects 23, 24 or 27, further comprising: a first time difference parameter is associated with the first type of alignment and a second time difference parameter is associated with the second type of alignment.

In aspect 29, the method of aspects 23, 24, 27 or 28, further comprising: the parent IAB node sends both the first time difference parameter and the second time difference parameter to the IAB node.

In aspect 30, the method of aspect 29, further comprising: the parent IAB node sends the first time difference parameter and the second time difference parameter to the IAB node in separate messages.

In aspect 31, the method of aspect 29, further comprising: the parent IAB node sends the first time difference parameter and the second time difference parameter to the IAB node in the same message.

In aspect 32, the method of aspects 23, 24 or 27, further comprising: the first time difference parameter is associated with the first type of alignment and the second time difference parameter is a time offset associated with the second type of alignment, the time offset being relative to the first time difference parameter.

In aspect 33, the method of aspect 32, further comprising: the parent IAB node sends both the first time difference parameter and the second time difference parameter to the IAB node.

In aspect 34, the method of aspect 33, further comprising: the parent IAB node sends the first time difference parameter and the second time difference parameter to the IAB node in separate messages.

In aspect 35, the method of aspect 33, further comprising: the parent IAB node sends the first time difference parameter and the second time difference parameter to the IAB node in the same message.

In aspect 36, the method according to any one of aspects 27-35, comprising: the indication of the time difference parameter further includes a flag corresponding to a type of alignment associated with the time difference parameter.

In aspect 37, the method of any one of aspects 27-36, further comprising: the resource in which the indication of the time difference parameter is sent also indicates a type of alignment associated with the time difference parameter.

Aspect 38 is an apparatus for wireless communication, comprising: means for performing the method of any one of aspects 23-37.

In aspect 39, the apparatus of aspect 38, further comprising at least one of an antenna or a transceiver coupled to the at least one antenna.

Aspect 40 is an apparatus for wireless communication, comprising: a memory; and at least one processor coupled to the memory and configured to perform the method according to any one of aspects 23-37 based at least in part on information stored in the memory.

In aspect 41, the apparatus of aspect 40, further comprising at least one of an antenna or a transceiver coupled to the at least one antenna and the at least one processor.

Aspect 42 is a non-transitory computer-readable medium storing computer-executable code, which when executed by a processor, causes the processor to perform the method according to any one of aspects 23-37.

Claims

1. An apparatus for wireless communication at an Integrated Access and Backhaul (IAB) node, comprising:

a memory; and

at least one processor coupled to the memory and configured to, based at least in part on information stored in the memory:

receiving a time difference parameter from a parent IAB node for over-the-air synchronization in an IAB network; and

the transmit or receive timing at the IAB node is adjusted based on the time difference parameter for one of a plurality of types of IAB node alignments.

2. The apparatus of claim 1, further comprising:

at least one transceiver coupled to the at least one processor and configured to receive the time difference parameter, wherein the plurality of types of the IAB node alignments comprise:

a first type of alignment comprising downlink transmit timing alignment across each IAB node of the IAB network,

alignment of a second type between uplink transmissions at an IAB mobile terminal (IAB-MT) of the IAB node and downlink transmissions at an IAB distributed unit (IAB-DU) of the IAB node, and

a third type of alignment between downlink reception at the IAB-MT of the IAB node and uplink reception at the IAB-DU of the IAB node.

3. The apparatus of claim 2, wherein the time difference parameter is associated with the first type of alignment and the third type of alignment.

4. The apparatus of claim 2, wherein the time difference parameter corresponds to a timing increment (T _delta ) And the IAB node is based on the T according to the first type of alignment from the plurality of types of the IAB node alignments _delta To adjust the downlink transmission time of the IAB node.

5. The apparatus of claim 4, wherein for the T _delta Indicates to the IAB node to apply the first type of alignment.

6. The apparatus of claim 2, wherein the time difference parameter corresponds to an offset parameter indicated with a timing advance command for the third type of alignment, wherein the at least one processor is further configured to:

calculating T from the offset parameter _delta And utilizing the T based on the third type of alignment _delta To adjust the sending or the receiving of the IAB node.

7. The apparatus of claim 2, wherein a first time difference parameter is associated with the first type of alignment and a second time difference parameter is associated with the second type of alignment.

8. The apparatus of claim 7, wherein the at least one processor is configured to: both the first time difference parameter and the second time difference parameter are received from the parent IAB node.

9. The apparatus of claim 8, wherein the at least one processor is configured to: the first time difference parameter and the second time difference parameter are received in separate messages from the parent IAB node or in the same message from the parent IAB node.

10. The apparatus of claim 7, wherein the first time difference parameter is associated with the first type of alignment and the second time difference parameter is a time offset associated with the second type of alignment, the time offset being relative to the first time difference parameter.

11. The apparatus of claim 10, wherein the at least one processor is configured to: both the first time difference parameter and the second time difference parameter are received from the parent IAB node.

12. The apparatus of claim 11, wherein the at least one processor is configured to: the first time difference parameter and the second time difference parameter are received in separate messages from the parent IAB node.

13. The apparatus of claim 11, wherein the at least one processor is configured to: the first time difference parameter and the second time difference parameter are received in the same message from the parent IAB node.

14. The apparatus of claim 2, wherein the indication of the time difference parameter received from the parent IAB node is to indicate an association with one of the multiple types of the IAB node alignments.

15. The apparatus of claim 14, wherein the indication of the time difference parameter comprises a flag corresponding to a type of alignment associated with the time difference parameter.

16. The apparatus of claim 14, wherein a resource in which the indication of the time difference parameter is received indicates a type of alignment associated with the time difference parameter.

17. An apparatus for wireless communication at a parent Integrated Access and Backhaul (IAB) node, comprising:

a memory; and

transmitting or receiving communication with an IAB node that is a child node of the parent IAB node; and

A time difference parameter is sent for over-the-air synchronization in an IAB network, the time difference parameter being applicable to one of a plurality of types of IAB node alignment.

18. The apparatus of claim 17, further comprising:

at least one transceiver coupled to the at least one processor, wherein the plurality of types of the IAB node alignments comprise:

19. The apparatus of claim 18, wherein the time difference parameter corresponds to a timing increment (T _delta ) The T is _delta Is based on a time difference between an uplink reception time and a downlink transmission time at the parent IAB node.

20. The apparatus of claim 19, wherein for the T _delta Indicates to the IAB node to apply the first type of alignment.

21. The apparatus of claim 18, wherein the indication of the time difference parameter from the parent IAB node is used to indicate an association with one of the multiple types of IAB node alignment.

22. The apparatus of claim 21, wherein a first time difference parameter is associated with the first type of alignment and a second time difference parameter is associated with the second type of alignment.

23. The apparatus of claim 22, wherein the at least one processor is configured to: transmitting both the first time difference parameter and the second time difference parameter to the IAB node, and wherein the at least one processor is configured to:

transmitting the first time difference parameter and the second time difference parameter to the IAB node in separate messages, or

And transmitting the first time difference parameter and the second time difference parameter to the IAB node in the same message.

24. The apparatus of claim 22, wherein the first time difference parameter is associated with the first type of alignment and the second time difference parameter is a time offset associated with the second type of alignment, the time offset being relative to the first time difference parameter, wherein the at least one processor is configured to:

25. The apparatus of claim 21, wherein the indication of the time difference parameter comprises a flag corresponding to a type of alignment associated with the time difference parameter.

26. A method of wireless communication at an Integrated Access and Backhaul (IAB) node, comprising:

27. The method of claim 26, wherein the plurality of types of the IAB node alignments comprise:

28. The method of claim 27, wherein the time difference parameter corresponds to a timing increment (T _delta )。

29. A method of wireless communication at a parent Integrated Access and Backhaul (IAB) node, comprising:

30. The method of claim 29, wherein the plurality of types of the IAB node alignments comprise: