WO2022087088A1 - Iab topology-wide fairness and downlink flow control - Google Patents

Abstract

An apparatus and system to provide load balancing and congestion mitigation in IAB networks are described. QoS load balancing is used to balance traffic among BH RLC channels holding UE bearers with similar QoS. A BAP header includes hop count of the routing path and UE bearer identity for scheduling among UEs having different hop numbers. Downstream hop-by-hop flow control for long-term congestion uses feedback transmitted from the congested node to parent nodes to indicate cessation of congestion. Hop-by-hop flow control is triggered by reception of flow control feedback from a child node. A congestion indication of an intermediate node is sent to a child node. Various BAP PDU values indicate a buffer load of the IAB node for a BH RLC channel pr BAP routing ID is less than a threshold, or provides the congestion indication.

Description

IAB TOPOLOGY- WIDE FAIRNESS AND DOWNLINK FLOW CONTROL

PRIORITY CLAIM

[0001] This application claims the benefit of priority to United States Provisional Patent Application Serial No. 63/094,730, filed October 21, 2020, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] Embodiments pertain to next generation wireless communications. In particular, some embodiments relate to Integrated Access Backhaul (IAB) fairness in 5G networks.

BACKGROUND

[0003] The use and complexity of wireless systems, which include 5^th generation (5G) networks and are starting to include sixth generation (6G) networks among others, has increased due to both an increase in the types of devices user equipment (UEs) using network resources as well as the amount of data and bandwidth being used by various applications, such as video streaming, operating on these UEs. With the vast increase in number and diversity of communication devices, the corresponding network environment, including routers, switches, bridges, gateways, firewalls, and load balancers, has become increasingly complicated. As expected, a number of issues abound with the advent of any new technology.

BRIEF DESCRIPTION OF THE FIGURES

[0004] In the figures, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The figures illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document. [0005] FIG. 1 A illustrates an architecture of a network, in accordance with some aspects.

[0006] FIG. IB illustrates a non-roaming 5G system architecture in accordance with some aspects.

[0007] FIG. 1C illustrates a non-roaming 5G system architecture in accordance with some aspects.

[0008] FIG. 2 illustrates a block diagram of a communication device in accordance with some embodiments.

[0009] FIG. 3 illustrates an IAB network in accordance with some aspects.

[0010] FIG. 4 illustrates long-term congestion at an access IAB node in accordance with some aspects.

[0011] FIG. 5 illustrates long-term congestion at an intermediate IAB node in accordance with some aspects.

DETAILED DESCRIPTION

[0012] The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims.

[0013] FIG. 1 A illustrates an architecture of a network in accordance with some aspects. The network 140 A includes 3 GPP LTE/4G and NG network functions that may be extended to 6G functions. Accordingly, although 5G will be referred to, it is to be understood that this is to extend as able to 6G structures, systems, and functions. A network function can be implemented as a discrete network element on a dedicated hardware, as a software instance running on dedicated hardware, and/or as a virtualized function instantiated on an appropriate platform, e.g., dedicated hardware or a cloud infrastructure.

[0014] The network 140 A is shown to include user equipment (UE) 101 and UE 102. The UEs 101 and 102 are illustrated as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks) but may also include any mobile or non-mobile computing device, such as portable (laptop) or desktop computers, wireless handsets, drones, or any other computing device including a wired and/or wireless communications interface. The UEs 101 and 102 can be collectively referred to herein as UE 101, and UE 101 can be used to perform one or more of the techniques disclosed herein.

[0015] Any of the radio links described herein (e.g., as used in the network 140 A or any other illustrated network) may operate according to any exemplary radio communication technology and/or standard. Any spectrum management scheme including, for example, dedicated licensed spectrum, unlicensed spectrum, (licensed) shared spectrum (such as Licensed Shared Access (LSA) in 2.3-2.4 GHz, 3.4-3.6 GHz, 3.6-3.8 GHz, and other frequencies and Spectrum Access System (SAS) in 3.55-3.7 GHz and other frequencies). Different Single Carrier or Orthogonal Frequency Domain Multiplexing (OFDM) modes (CP-OFDM, SC-FDMA, SC-OFDM, filter bank-based multicarrier (FBMC), OFDMA, etc.), and in particular 3GPP NR, may be used by allocating the OFDM carrier data bit vectors to the corresponding symbol resources.

[0016] In some aspects, any of the UEs 101 and 102 can comprise an Internet-of-Things (loT) UE or a Cellular loT (CIoT) UE, which can comprise a network access layer designed for low-power loT applications utilizing shortlived UE connections. In some aspects, any of the UEs 101 and 102 can include a narrowband (NB) loT UE (e.g., such as an enhanced NB-IoT (eNB-IoT) UE and Further Enhanced (FeNB-IoT) UE). An loT UE can utilize technologies such as machine-to-machine (M2M) or machine-type communications (MTC) for exchanging data with an MTC server or device via a public land mobile network (PLMN), Proximity-Based Service (ProSe) or device-to-device (D2D) communication, sensor networks, or loT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An loT network includes interconnecting loT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived connections. The loT UEs may execute background applications (e.g., keepalive messages, status updates, etc.) to facilitate the connections of the loT network. In some aspects, any of the UEs 101 and 102 can include enhanced MTC (eMTC) UEs or further enhanced MTC (FeMTC) UEs. [0017] The UEs 101 and 102 may be configured to connect, e.g., communicatively couple, with a radio access network (RAN) 110. The RAN 110 may be, for example, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), a NextGen RAN (NG RAN), or some other type of RAN.

[0018] The UEs 101 and 102 utilize connections 103 and 104, respectively, each of which comprises a physical communications interface or layer (discussed in further detail below); in this example, the connections 103 and 104 are illustrated as an air interface to enable communicative coupling, and can be consistent with cellular communications protocols, such as a Global System for Mobile Communications (GSM) protocol, a code-division multiple access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC) protocol, a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a 5G protocol, a 6G protocol, and the like.

[0019] In an aspect, the UEs 101 and 102 may further directly exchange communication data via a ProSe interface 105. The ProSe interface 105 may alternatively be referred to as a sidelink (SL) interface comprising one or more logical channels, including but not limited to a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Discovery Channel (PSDCH), a Physical Sidelink Broadcast Channel (PSBCH), and a Physical Sidelink Feedback Channel (PSFCH).

[0020] The UE 102 is shown to be configured to access an access point (AP) 106 via connection 107. The connection 107 can comprise a local wireless connection, such as, for example, a connection consistent with any IEEE 802.11 protocol, according to which the AP 106 can comprise a wireless fidelity (WiFi®) router. In this example, the AP 106 is shown to be connected to the Internet without connecting to the core network of the wireless system (described in further detail below).

[0021] The RAN 110 can include one or more access nodes that enable the connections 103 and 104. These access nodes (ANs) can be referred to as base stations (BSs), NodeBs, evolved NodeBs (eNBs), Next Generation NodeBs (gNBs), RAN nodes, and the like, and can comprise ground stations (e.g., terrestrial access points) or satellite stations providing coverage within a geographic area (e.g., a cell). In some aspects, the communication nodes 111 and 112 can be transmission/reception points (TRPs). In instances when the communication nodes 111 and 112 are NodeBs (e.g., eNBs or gNBs), one or more TRPs can function within the communication cell of the NodeBs. The RAN 110 may include one or more RAN nodes for providing macrocells, e.g., macro RAN node 111, and one or more RAN nodes for providing femtocells or picocells (e.g., cells having smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells), e.g., low power (LP) RAN node 112. [0022] Any of the RAN nodes 111 and 112 can terminate the air interface protocol and can be the first point of contact for the UEs 101 and 102. In some aspects, any of the RAN nodes 111 and 112 can fulfill various logical functions for the RAN 110 including, but not limited to, radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management. In an example, any of the nodes 111 and/or 112 can be a gNB, an eNB, or another type of RAN node.

[0023] The RAN 110 is shown to be communicatively coupled to a core network (CN) 120 via an SI interface 113. In aspects, the CN 120 may be an evolved packet core (EPC) network, a NextGen Packet Core (NPC) network, or some other type of CN (e.g., as illustrated in reference to FIGS. 1B-1C). In this aspect, the SI interface 113 is split into two parts: the Sl-U interface 114, which carries traffic data between the RAN nodes 111 and 112 and the serving gateway (S-GW) 122, and the Sl-mobility management entity (MME) interface 115, which is a signaling interface between the RAN nodes 111 and 112 and MMEs

121.

[0024] In this aspect, the CN 120 comprises the MMEs 121, the S-GW

122, the Packet Data Network (PDN) Gateway (P-GW) 123, and a home subscriber server (HSS) 124. The MMEs 121 may be similar in function to the control plane of legacy Serving General Packet Radio Service (GPRS) Support Nodes (SGSN). The MMEs 121 may manage mobility aspects in access such as gateway selection and tracking area list management. The HSS 124 may comprise a database for network users, including subscription-related information to support the network entities' handling of communication sessions. The CN 120 may comprise one or several HSSs 124, depending on the number of mobile subscribers, on the capacity of the equipment, on the organization of the network, etc. For example, the HSS 124 can provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location dependencies, etc.

[0025] The S-GW 122 may terminate the SI interface 113 towards the RAN 110, and routes data packets between the RAN 110 and the CN 120. In addition, the S-GW 122 may be a local mobility anchor point for inter-RAN node handovers and also may provide an anchor for inter-3GPP mobility. Other responsibilities of the S-GW 122 may include a lawful intercept, charging, and some policy enforcement.

[0026] The P-GW 123 may terminate an SGi interface toward a PDN. The P-GW 123 may route data packets between the CN 120 and external networks such as a network including the application server 184 (alternatively referred to as application function (AF)) via an Internet Protocol (IP) interface 125. The P-GW 123 can also communicate data to other external networks 131 A, which can include the Internet, IP multimedia subsystem (IPS) network, and other networks. Generally, the application server 184 may be an element offering applications that use IP bearer resources with the core network (e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). In this aspect, the P-GW 123 is shown to be communicatively coupled to an application server 184 via an IP interface 125. The application server 184 can also be configured to support one or more communication services (e.g., Voice-over-Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UEs 101 and 102 via the CN 120.

[0027] The P-GW 123 may further be a node for policy enforcement and charging data collection. Policy and Charging Rules Function (PCRF) 126 is the policy and charging control element of the CN 120. In a non-roaming scenario, in some aspects, there may be a single PCRF in the Home Public Land Mobile Network (HPLMN) associated with a UE's Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with a local breakout of traffic, there may be two PCRFs associated with a UE's IP-CAN session: a Home PCRF (H-PCRF) within an HPLMN and a Visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF 126 may be communicatively coupled to the application server 184 via the P-GW 123. [0028] In some aspects, the communication network 140 A can be an loT network or a 5G or 6G network, including 5G new radio network using communications in the licensed (5G NR) and the unlicensed (5GNR-U) spectrum. One of the current enablers of loT is the narrowband-IoT (NB-IoT). Operation in the unlicensed spectrum may include dual connectivity (DC) operation and the standalone LTE system in the unlicensed spectrum, according to which LTE-based technology solely operates in unlicensed spectrum without the use of an “anchor” in the licensed spectrum, called MulteFire. Further enhanced operation of LTE systems in the licensed as well as unlicensed spectrum is expected in future releases and 5G systems. Such enhanced operations can include techniques for sidelink resource allocation and UE processing behaviors for NR sidelink V2X communications.

[0029] An NG system architecture (or 6G system architecture) can include the RAN 110 and a 5G core network (5GC) 120. The NG-RAN 110 can include a plurality of nodes, such as gNBs and NG-eNBs. The CN 120 (e.g., a 5G core network/5GC) can include an access and mobility function (AMF) and/or a user plane function (UPF). The AMF and the UPF can be communicatively coupled to the gNBs and the NG-eNBs via NG interfaces. More specifically, in some aspects, the gNBs and the NG-eNBs can be connected to the AMF by NG-C interfaces, and to the UPF by NG-U interfaces. The gNBs and the NG-eNBs can be coupled to each other via Xn interfaces. [0030] In some aspects, the NG system architecture can use reference points between various nodes. In some aspects, each of the gNBs and the NG- eNBs can be implemented as a base station, a mobile edge server, a small cell, a home eNB, and so forth. In some aspects, a gNB can be a master node (MN) and NG-eNB can be a secondary node (SN) in a 5G architecture.

[0031] FIG. IB illustrates a non-roaming 5G system architecture in accordance with some aspects. In particular, FIG. IB illustrates a 5G system architecture 140B in a reference point representation, which may be extended to a 6G system architecture. More specifically, UE 102 can be in communication with RAN 110 as well as one or more other 5GC network entities. The 5G system architecture 140B includes a plurality of network functions (NFs), such as an AMF 132, session management function (SMF) 136, policy control function (PCF) 148, application function (AF) 150, UPF 134, network slice selection function (NSSF) 142, authentication server function (AUSF) 144, and unified data management (UDM)/home subscriber server (HSS) 146.

[0032] The UPF 134 can provide a connection to a data network (DN) 152, which can include, for example, operator services, Internet access, or third- party services. The AMF 132 can be used to manage access control and mobility and can also include network slice selection functionality. The AMF 132 may provide UE-based authentication, authorization, mobility management, etc., and may be independent of the access technologies. The SMF 136 can be configured to set up and manage various sessions according to network policy. The SMF 136 may thus be responsible for session management and allocation of IP addresses to UEs. The SMF 136 may also select and control the UPF 134 for data transfer. The SMF 136 may be associated with a single session of a UE 101 or multiple sessions of the UE 101. This is to say that the UE 101 may have multiple 5G sessions. Different SMFs may be allocated to each session. The use of different SMFs may permit each session to be individually managed. As a consequence, the functionalities of each session may be independent of each other.

[0033] The UPF 134 can be deployed in one or more configurations according to the desired service type and may be connected with a data network. The PCF 148 can be configured to provide a policy framework using network slicing, mobility management, and roaming (similar to PCRF in a 4G communication system). The UDM can be configured to store subscriber profiles and data (similar to an HSS in a 4G communication system).

[0034] The AF 150 may provide information on the packet flow to the PCF 148 responsible for policy control to support a desired QoS. The PCF 148 may set mobility and session management policies for the UE 101. To this end, the PCF 148 may use the packet flow information to determine the appropriate policies for proper operation of the AMF 132 and SMF 136. The AUSF 144 may store data for UE authentication.

[0035] In some aspects, the 5G system architecture 140B includes an IP multimedia subsystem (IMS) 168B as well as a plurality of IP multimedia core network subsystem entities, such as call session control functions (CSCFs). More specifically, the IMS 168B includes a CSCF, which can act as a proxy CSCF (P-CSCF) 162BE, a serving CSCF (S-CSCF) 164B, an emergency CSCF (E-CSCF) (not illustrated in FIG. IB), or interrogating CSCF (I-CSCF) 166B. The P-CSCF 162B can be configured to be the first contact point for the UE 102 within the IM subsystem (IMS) 168B. The S-CSCF 164B can be configured to handle the session states in the network, and the E-CSCF can be configured to handle certain aspects of emergency sessions such as routing an emergency request to the correct emergency center or PSAP. The I-CSCF 166B can be configured to function as the contact point within an operator's network for all IMS connections destined to a subscriber of that network operator, or a roaming subscriber currently located within that network operator's service area. In some aspects, the I-CSCF 166B can be connected to another IP multimedia network 170E, e.g. an IMS operated by a different network operator.

[0036] In some aspects, the UDM/HSS 146 can be coupled to an application server 160E, which can include a telephony application server (TAS) or another application server (AS). The AS 160B can be coupled to the IMS 168B via the S-CSCF 164B or the I-CSCF 166B.

[0037] A reference point representation shows that interaction can exist between corresponding NF services. For example, FIG. IB illustrates the following reference points: N1 (between the UE 102 and the AMF 132), N2 (between the RAN 110 and the AMF 132), N3 (between the RAN 110 and the UPF 134), N4 (between the SMF 136 and the UPF 134), N5 (between the PCF 148 and the AF 150, not shown), N6 (between the UPF 134 and the DN 152), N7 (between the SMF 136 and the PCF 148, not shown), N8 (between the UDM 146 and the AMF 132, not shown), N9 (between two UPFs 134, not shown), N10 (between the UDM 146 and the SMF 136, not shown), Ni l (between the AMF 132 and the SMF 136, not shown), N12 (between the AUSF 144 and the AMF 132, not shown), N13 (between the AUSF 144 and the UDM 146, not shown), N14 (between two AMFs 132, not shown), N15 (between the PCF 148 and the AMF 132 in case of a non-roaming scenario, or between the PCF 148 and a visited network and AMF 132 in case of a roaming scenario, not shown), N16 (between two SMFs, not shown), and N22 (between AMF 132 and NSSF 142, not shown). Other reference point representations not shown in FIG. IB can also be used.

[0038] FIG. 1C illustrates a 5G system architecture 140C and a servicebased representation. In addition to the network entities illustrated in FIG. IB, system architecture 140C can also include a network exposure function (NEF) 154 and a network repository function (NRF) 156. In some aspects, 5G system architectures can be service-based and interaction between network functions can be represented by corresponding point-to-point reference points Ni or as service-based interfaces.

[0039] In some aspects, as illustrated in FIG. 1C, service-based representations can be used to represent network functions within the control plane that enable other authorized network functions to access their services. In this regard, 5G system architecture 140C can include the following servicebased interfaces: Namf 158H (a service-based interface exhibited by the AMF 132), Nsmf 1581 (a service-based interface exhibited by the SMF 136), Nnef 158B (a service-based interface exhibited by the NEF 154), Npcf 158D (a service-based interface exhibited by the PCF 148), a Nudm 158E (a servicebased interface exhibited by the UDM 146), Naf 158F (a service-based interface exhibited by the AF 150), Nnrf 158C (a service-based interface exhibited by the NRF 156), Nnssf 158A (a service-based interface exhibited by the NSSF 142), Nausf 158G (a service-based interface exhibited by the AUSF 144). Other service-based interfaces (e.g., Nudr, N5g-eir, and Nudsf) not shown in FIG. 1C can also be used.

[0040] NR-V2X architectures may support high-reliability low latency sidelink communications with a variety of traffic patterns, including periodic and aperiodic communications with random packet arrival time and size.

Techniques disclosed herein can be used for supporting high reliability in distributed communication systems with dynamic topologies, including sidelink NR V2X communication systems.

[0041] FIG. 2 illustrates a block diagram of a communication device in accordance with some embodiments. The communication device 200 may be a UE such as a specialized computer, a personal or laptop computer (PC), a tablet PC, or a smart phone, dedicated network equipment such as an eNB, a server running software to configure the server to operate as a network device, a virtual device, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. For example, the communication device 200 may be implemented as one or more of the devices shown in FIGS. 1 A-1C. Note that communications described herein may be encoded before transmission by the transmitting entity (e.g., UE, gNB) for reception by the receiving entity (e.g., gNB, UE) and decoded after reception by the receiving entity.

[0042] Examples, as described herein, may include, or may operate on, logic or a number of components, modules, or mechanisms. Modules and components are tangible entities (e.g., hardware) capable of performing specified operations and may be configured or arranged in a certain manner. In an example, circuits may be arranged (e.g., internally or with respect to external entities such as other circuits) in a specified manner as a module. In an example, the whole or part of one or more computer systems (e.g., a standalone, client or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, an application portion, or an application) as a module that operates to perform specified operations. In an example, the software may reside on a machine readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations.

[0043] Accordingly, the term “module” (and “component”) is understood to encompass a tangible entity, be that an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transitorily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operation described herein. Considering examples in which modules are temporarily configured, each of the modules need not be instantiated at any one moment in time. For example, where the modules comprise a general-purpose hardware processor configured using software, the general -purpose hardware processor may be configured as respective different modules at different times. Software may accordingly configure a hardware processor, for example, to constitute a particular module at one instance of time and to constitute a different module at a different instance of time.

[0044] The communication device 200 may include a hardware processor (or equivalently processing circuitry) 202 (e.g., a central processing unit (CPU), a GPU, a hardware processor core, or any combination thereof), a main memory 204 and a static memory 206, some or all of which may communicate with each other via an interlink (e.g., bus) 208. The main memory 204 may contain any or all of removable storage and non-removable storage, volatile memory or non-volatile memory. The communication device 200 may further include a display unit 210 such as a video display, an alphanumeric input device 212 (e.g., a keyboard), and a user interface (UI) navigation device 214 (e.g., a mouse). In an example, the display unit 210, input device 212 and UI navigation device 214 may be a touch screen display. The communication device 200 may additionally include a storage device (e.g., drive unit) 216, a signal generation device 218 (e.g., a speaker), a network interface device 220, and one or more sensors, such as a global positioning system (GPS) sensor, compass, accelerometer, or other sensor. The communication device 200 may further include an output controller, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.).

[0045] The storage device 216 may include a non-transitory machine readable medium 222 (hereinafter simply referred to as machine readable medium) on which is stored one or more sets of data structures or instructions 224 (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions 224 may also reside, completely or at least partially, within the main memory 204, within static memory 206, and/or within the hardware processor 202 during execution thereof by the communication device 200. While the machine readable medium 222 is illustrated as a single medium, the term "machine readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 224.

[0046] The term “machine readable medium” may include any medium that is capable of storing, encoding, or carrying instructions for execution by the communication device 200 and that cause the communication device 200 to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting machine readable medium examples may include solid-state memories, and optical and magnetic media. Specific examples of machine readable media may include: non-volatile memory, such as semiconductor memory devices (e.g., Electrically Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; Random Access Memory (RAM); and CD-ROM and DVD-ROM disks.

[0047] The instructions 224 may further be transmitted or received over a communications network using a transmission medium 226 via the network interface device 220 utilizing any one of a number of wireless local area network (WLAN) transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks. Communications over the networks may include one or more different protocols, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi, IEEE 802.16 family of standards known as WiMax, IEEE 802.15.4 family of standards, a Long Term Evolution (LTE) family of standards, a Universal Mobile Telecommunications System (UMTS) family of standards, peer-to-peer (P2P) networks, a next generation (NG)/5^th generation (5G) standards among others. In an example, the network interface device 220 may include one or more physical jacks (e.g., Ethernet, coaxial, or phonejacks) or one or more antennas to connect to the transmission medium 226.

[0048] Note that the term “circuitry” as used herein refers to, is part of, or includes hardware components such as an electronic circuit, a logic circuit, a processor (shared, dedicated, or group) and/or memory (shared, dedicated, or group), an Application Specific Integrated Circuit (ASIC), a field-programmable device (FPD) (e.g., a field-programmable gate array (FPGA), a programmable logic device (PLD), a complex PLD (CPLD), a high-capacity PLD (HCPLD), a structured ASIC, or a programmable SoC), digital signal processors (DSPs), etc., that are configured to provide the described functionality. In some embodiments, the circuitry may execute one or more software or firmware programs to provide at least some of the described functionality. The term “circuitry” may also refer to a combination of one or more hardware elements (or a combination of circuits used in an electrical or electronic system) with the program code used to carry out the functionality of that program code. In these embodiments, the combination of hardware elements and program code may be referred to as a particular type of circuitry.

[0049] The term “processor circuitry” or “processor” as used herein thus refers to, is part of, or includes circuitry capable of sequentially and automatically carrying out a sequence of arithmetic or logical operations, or recording, storing, and/or transferring digital data. The term “processor circuitry” or “processor” may refer to one or more application processors, one or more baseband processors, a physical central processing unit (CPU), a single- or multi-core processor, and/or any other device capable of executing or otherwise operating computer-executable instructions, such as program code, software modules, and/or functional processes.

[0050] Any of the radio links described herein may operate according to any one or more of the following radio communication technologies and/or standards including but not limited to: a Global System for Mobile Communications (GSM) radio communication technology, a General Packet Radio Service (GPRS) radio communication technology, an Enhanced Data Rates for GSM Evolution (EDGE) radio communication technology, and/or a Third Generation Partnership Project (3 GPP) radio communication technology, for example Universal Mobile Telecommunications System (UMTS), Freedom of Multimedia Access (FOMA), 3 GPP Long Term Evolution (LTE), 3 GPP Long Term Evolution Advanced (LTE Advanced), Code division multiple access 2000 (CDMA2000), Cellular Digital Packet Data (CDPD), Mobitex, Third Generation (3G), Circuit Switched Data (CSD), High-Speed Circuit- Switched Data (HSCSD), Universal Mobile Telecommunications System (Third Generation) (UMTS (3 G)), Wideband Code Division Multiple Access (Universal Mobile Telecommunications System) (W-CDMA (UMTS)), High Speed Packet Access (HSPA), High-Speed Downlink Packet Access (HSDPA), High-Speed Uplink Packet Access (HSUPA), High Speed Packet Access Plus (HSPA+), Universal Mobile Telecommunications System-Time-Division Duplex (UMTS-TDD), Time Division-Code Division Multiple Access (TD-CDMA), Time Division- Synchronous Code Division Multiple Access (TD-CDMA), 3rd Generation Partnership Project Release 8 (Pre-4th Generation) (3 GPP Rel. 8 (Pre-4G)), 3GPP Rel. 9 (3rd Generation Partnership Project Release 9), 3GPP Rel. 10 (3rd Generation Partnership Project Release 10) , 3GPP Rel. 11 (3rd Generation Partnership Project Release 11), 3GPP Rel. 12 (3rd Generation Partnership Project Release 12), 3GPP Rel. 13 (3rd Generation Partnership Project Release 13), 3GPP Rel. 14 (3rd Generation Partnership Project Release 14), 3GPP Rel. 15 (3rd Generation Partnership Project Release 15), 3GPP Rel. 16 (3rd Generation Partnership Project Release 16), 3GPP Rel. 17 (3rd Generation Partnership Project Release 17) and subsequent Releases (such as Rel. 18, Rel. 19, etc ), 3GPP 5G, 5G, 5G New Radio (5G NR), 3GPP 5G New Radio, 3GPP LTE Extra, LTE-Advanced Pro, LTE Licensed-Assisted Access (LAA), MuLTEfire, UMTS Terrestrial Radio Access (UTRA), Evolved UMTS Terrestrial Radio Access (E-UTRA), Long Term Evolution Advanced (4th Generation) (LTE Advanced (4G)), cdmaOne (2G), Code division multiple access 2000 (Third generation) (CDMA2000 (3G)), Evolution-Data Optimized or Evolution-Data Only (EV-DO), Advanced Mobile Phone System (1st Generation) (AMPS (1G)), Total Access Communication System/Extended Total Access Communication System (TACSZETACS), Digital AMPS (2nd Generation) (D-AMPS (2G)), Push-to-talk (PTT), Mobile Telephone System (MTS), Improved Mobile Telephone System (IMTS), Advanced Mobile Telephone System (AMTS), OLT (Norwegian for Offentlig Landmobil Telefoni, Public Land Mobile Telephony), MTD (Swedish abbreviation for Mobiltelefonisystem D, or Mobile telephony system D), Public Automated Land Mobile (Autotel/PALM), ARP (Finnish for Autoradiopuhelin, "car radio phone"), NMT (Nordic Mobile Telephony), High capacity version of NTT (Nippon Telegraph and Telephone) (Hicap), Cellular Digital Packet Data (CDPD), Mobitex, DataTAC, Integrated Digital Enhanced Network (iDEN), Personal Digital Cellular (PDC), Circuit Switched Data (CSD), Personal Handyphone System (PHS), Wideband Integrated Digital Enhanced Network (WiDEN), iBurst, Unlicensed Mobile Access (UMA), also referred to as also referred to as 3 GPP Generic Access Network, or GAN standard), Zigbee, Bluetooth(r), Wireless Gigabit Alliance (WiGig) standard, mmWave standards in general (wireless systems operating at 10-300 GHz and above such as WiGig, IEEE 802. Had, IEEE 802.1 lay, etc.), technologies operating above 300 GHz and THz bands, (3GPP/LTE based or IEEE 802.1 Ip or IEEE 802.1 Ibd and other) Vehi cl e-to- Vehicle (V2V) and Vehicle-to-X (V2X) and Vehicle-to- Infrastructure (V2I) and Infrastructure-to- Vehicle (12 V) communication technologies, 3GPP cellular V2X, DSRC (Dedicated Short Range Communications) communication systems such as Intelligent-Transport-Systems and others (typically operating in 5850 MHz to 5925 MHz or above (typically up to 5935 MHz following change proposals in CEPT Report 71)), the European ITS-G5 system (i.e. the European flavor of IEEE 802.1 Ip based DSRC, including ITS-G5A (i.e., Operation of ITS-G5 in European ITS frequency bands dedicated to ITS for safety re-lated applications in the frequency range 5,875 GHz to 5,905 GHz), ITS-G5B (i.e., Operation in European ITS frequency bands dedicated to ITS non- safety applications in the frequency range 5,855 GHz to 5,875 GHz), ITS-G5C (i.e., Operation of ITS applications in the frequency range 5,470 GHz to 5,725 GHz)), DSRC in Japan in the 700MHz band (including 715 MHz to 725 MHz), IEEE 802.1 Ibd based systems, etc.

[0051] Aspects described herein can be used in the context of any spectrum management scheme including dedicated licensed spectrum, unlicensed spectrum, license exempt spectrum, (licensed) shared spectrum (such as LSA = Licensed Shared Access in 2.3-2.4 GHz, 3.4-3.6 GHz, 3.6-3.8 GHz and further frequencies and SAS = Spectrum Access System / CBRS = Citizen Broadband Radio System in 3.55-3.7 GHz and further frequencies). Applicable spectrum bands include IMT (International Mobile Telecommunications) spectrum as well as other types of spectrum/bands, such as bands with national allocation (including 450 - 470 MHz, 902-928 MHz (note: allocated for example in US (FCC Part 15)), 863-868.6 MHz (note: allocated for example in European Union (ETSI EN 300 220)), 915.9-929.7 MHz (note: allocated for example in Japan), 917-923.5 MHz (note: allocated for example in South Korea), 755-779 MHz and 779-787 MHz (note: allocated for example in China), 790 - 960 MHz, 1710 - 2025 MHz, 2110 - 2200 MHz, 2300 - 2400 MHz, 2.4-2.4835 GHz (note: it is an ISM band with global availability and it is used by Wi-Fi technology family (1 Ib/g/n/ax) and also by Bluetooth), 2500 - 2690 MHz, 698-790 MHz, 610 - 790 MHz, 3400 - 3600 MHz, 3400 - 3800 MHz, 3800 - 4200 MHz, 3.55- 3.7 GHz (note: allocated for example in the US for Citizen Broadband Radio Service), 5.15-5.25 GHz and 5.25-5.35 GHz and 5.47-5.725 GHz and 5.725-5.85 GHz bands (note: allocated for example in the US (FCC part 15), consists four U-NII bands in total 500 MHz spectrum), 5.725-5.875 GHz (note: allocated for example in EU (ETSI EN 301 893)), 5.47-5.65 GHz (note: allocated for example in South Korea, 5925-7125 MHz and 5925-6425MHz band (note: under consideration in US and EU, respectively. Next generation Wi-Fi system is expected to include the 6 GHz spectrum as operating band but it is noted that, as of December 2017, Wi-Fi system is not yet allowed in this band. Regulation is expected to be finished in 2019-2020 time frame), IMT-advanced spectrum, IMT-2020 spectrum (expected to include 3600-3800 MHz, 3800 - 4200 MHz, 3.5 GHz bands, 700 MHz bands, bands within the 24.25-86 GHz range, etc.), spectrum made available under FCC's "Spectrum Frontier" 5G initiative (including 27.5 - 28.35 GHz, 29.1 - 29.25 GHz, 31 - 31.3 GHz, 37 - 38.6 GHz, 38.6 - 40 GHz, 42 - 42.5 GHz, 57 - 64 GHz, 71 - 76 GHz, 81 - 86 GHz and 92 - 94 GHz, etc), the ITS (Intelligent Transport Systems) band of 5.9 GHz (typically 5.85-5.925 GHz) and 63-64 GHz, bands currently allocated to WiGig such as WiGig Band 1 (57.24-59.40 GHz), WiGig Band 2 (59.40-61.56 GHz) and WiGig Band 3 (61.56-63.72 GHz) and WiGig Band 4 (63.72-65.88 GHz), 57- 64/66 GHz (note: this band has near-global designation for Multi-Gigabit Wireless Systems (MGWS)/WiGig . In US (FCC part 15) allocates total 14 GHz spectrum, while EU (ETSI EN 302 567 and ETSI EN 301 217-2 for fixed P2P) allocates total 9 GHz spectrum), the 70.2 GHz - 71 GHz band, any band between 65.88 GHz and 71 GHz, bands currently allocated to automotive radar applications such as 76-81 GHz, and future bands including 94-300 GHz and above. Furthermore, the scheme can be used on a secondary basis on bands such as the TV White Space bands (typically below 790 MHz) where in particular the 400 MHz and 700 MHz bands are promising candidates. Besides cellular applications, specific applications for vertical markets may be addressed such as PMSE (Program Making and Special Events), medical, health, surgery, automotive, low-latency, drones, etc. applications.

[0052] Aspects described herein can also implement a hierarchical application of the scheme is possible, e.g., by introducing a hierarchical prioritization of usage for different types of users (e.g., low/medium/high priority, etc.), based on a prioritized access to the spectrum e.g., with highest priority to tier-1 users, followed by tier-2, then tier-3, etc. users, etc.

[0053] Aspects described herein can also be applied to different Single Carrier or OFDM flavors (CP-OFDM, SC-FDMA, SC-OFDM, filter bank-based multicamer (FBMC), OFDMA, etc.) and in particular 3GPP NR (New Radio) by allocating the OFDM carrier data bit vectors to the corresponding symbol resources.

[0054] Some of the features in this document are defined for the network side, such as APs, eNBs, NR or gNBs - note that this term is typically used in the context of 3GPP 5G and 6G communication systems, etc. Still, a UE may take this role as well and act as an AP, eNB, or gNB; that is some or all features defined for network equipment may be implemented by a UE.

[0055] As above, 5G networks support enhanced mobile broadband (eMBB) and ultra-reliable low latency communications (URLLC) using gigahertz (GHz). However, due to the shorter wavelengths in this spectrum have a smaller signal range and are more susceptible to interference and degradation. To counter this problem, the number of antennas may be increased, which leads to an increase in backhaul bandwidth capacity among the increased number of gNBs using IAB. IAB allows for multi-hop backhauling using the same frequencies employed for UEs. The IAB Mobile Termination (MT) antenna may include independent antenna arrays or shared antennas (virtual lAB-MTs (vIAB-MT)). Integrated Access and Backhaul specifications define two antenna system types: an IAB node and an IAB donor. IAB donors terminate the backhaul traffic from distributed IAB nodes. The nodes can be backhaul endpoints or relays between the endpoints and the donor. Both IAB donors and nodes serve mobile UEs.

[0056] IAB uses a radio access network (RAN) model similar to that employed in the Open RAN (O-RAN) architecture; a distributed unit (DU) and a central unit (CU). Thus, the IAB nodes contain a DU and the IAB donors also include a CU. A single IAB system of one or more IAB nodes and the IAB donor form a gNB. The backhaul may be insolated, so routing changes or problems are not propagated into the 5G core (5GC) or other adjacent gNBs. [0057] In an IAB Network, an IAB node can connect to different nodes via different links. The IAB node can connect to its parent node (an IAB donor or another IAB node) through parent backhaul (BH) link, connect to a child UE through child access (AC) link, and connect to its child IAB node through child BH link. Note that as used herein, parent node is an immediate parent node of the IAB node, rather than a multi -generational parent node (e.g., grandparent node), and a child node is an immediate child node of the IAB node rather than a multi -generational child node (e.g., grandchild node).

[0058] In current IAB network architectures, the CU/DU split has been leveraged such that each IAB node holds a DU and has a MT function. The IAB node connects to its parent IAB node or the IAB donor via the MT function in a manner similar to communications with a UE. The IAB node communicates with its child UEs and child MTs via the DU function in a manner similar to communications with a base station. Radio Resource Control (RRC) signaling is used between the CU in the IAB donor and the UE/MT, while F1AP signaling is used between the CU and the DU in an IAB node.

[0059] One IAB enhancement is topology-wide fairness, multi-hop latency and congestion mitigation. Congestion, for example, is the inability of the IAB node to transmit data as fast as data is being received, thereby increasing the buffer load and delaying the delivery of data from the IAB node. Topology-wide fairness may be used to satisfy different quality of service (QoS) requirements and meet end-user experience expectations. For an IAB network, in general fairness ensures that performance in the IAB network is agnostic to the number of hops and amount of traffic for a particular IAB node. Several issues may cause unfair scheduling, including an unbalanced workload among BH radio link control (RLC) channels, accumulated latency from multiple hops, and an unbalanced amount of data traffic among UE radio bearers.

[0060] Congestion migration may also arise in the IAB network. Due to emerging traffic transmitted from the IAB donor to UEs via multiple IAB nodes, a child IAB node may not be aware how much downstream data will be received from its parent nodes. This may lead to congestion at one or more intermediate or access IAB nodes. Moreover, a particular IAB node may experience longterm congestion due to massive downstream traffic or ineffective adjustment of the traffic volume. Long-term congestion may lead to several issues at the access IAB node and intermediate IAB node, including that the congested IAB node keeps sending flow control feedback if its buffer size continuously exceeds the threshold. In addition, series congestion may be present at the parent node of the congested IAB node and also other ancestor nodes of the congested IAB node, packets may be dropped due to the congestion, and resources may be wasted at child IAB nodes due to lack of resource at a parent IAB node. Hence, downstream hop-by-hop now control may be considered under a long-term congestion scenario to shorten the congestion period and prevent potential packet drop at a congested IAB node. Accordingly, IAB network topology -wide fairness and downstream hop-by-hop flow control enhancement for long-term congestion are described.

[0061] FIG. 3 illustrates an IAB network in accordance with some aspects. In particular, FIG. 3 shows an example of an IAB network with multiple hops and 6 attached UEs. In FIG. 3, UE1, UE2, UE3 and UE4 have a single radio bearer with the same QoS profile. In addition, the routing paths of UE1, UE2, UE3 and UE4 follow the below table:

[0062] Accordingly, upstream fairness scheduling at two different levels are considered herein: 1) centralized fairness among BH RLC channels with similar QoS requirements, and 2) distributed fairness at an intermediate IAB- DU.

[0063] For the IAB network, load balancing may not be targeted purely to distribute traffic evenly in all paths/BH RLC channels. In the IAB network, different BH RLC channels may map to a single UE bearer or multiple UE bearers with similar QoS profiles. In this case, traffic may be balanced between BH RLC channels that have similar QoS requirements, also herein referred to as “QoS-based load balancing”. As shown in FIG. 3, BH RLC channel A and B have similar QoS requirements. Thus, by considering load balancing between the BH RLC channels, the IAB donor CU can change UE4’s routing path into “IAB node 6 <-> IAB node 4 <-> IAB node 1 <-> IAB Donor”, thus balancing traffic between channel A and B. This balancing may help to avoid possible congestion at IAB node 2, which may otherwise lead to delay and unfairness to UE1, UE3, and UE4. Load information, such as radio resource usage, a Transport Network Layer (TNL) capacity indicator, a cell capacity class value, a hardware (HW) capacity indicator, and a number of active UEs may be reported per BH RLC channel.

[0064] Moreover, to better facilitate fairness scheduling decisions by the intermediate IAB node, the hop count and amount of data of the child IAB nodes (in some cases all descendant IAB nodes) and UEs supported by these IAB nodes compared to the intermediate IAB node may be used to assist upstream traffic topology-wide fairness. For example, in FIG. 3, IAB node 5 is responsible for resource scheduling for UE3 and IAB node 6 (to which UE4 is attached). The BH RLC channel between IAB node 5 and IAB node 6 carries the radio bearer of UE4, which has same QoS requirement as UE3. Compared to UE3, UE4 has one more hop in its routing path to the IAB donor. For upstream traffic, since IAB node 5 is connected to both IAB node 6 and UE3, IAB node 5 is responsible for resource scheduling for the radio bearer used by UE3, as well as UE bearers from IAB node 6 (including UE bearers from UE4). Recalling that UE3 and UE4 have same QoS priority, to avoid longer latency (caused by an increased hop-count) to UE4 than UE3, IAB node 5 may set the UE bearers of UE4 (which come from IAB node 6) to a higher priority than those of UE3. However, IAB node 5 may not be aware of the existence of UE4 as only the Backhaul Adaptation Protocol (BAP) header is able to be decoded. Hence, the BAP header may be altered to include UE bearer identity and hop count of the routing path to enable fairness handling.

[0065] Embodiment 2: Downstream hop-by-hop flow control for long-term congestion

[0066] Long-term congestion may occur in the access IAB node and the intermediate IAB node. FIG. 4 illustrates long-term congestion at an access IAB node in accordance with some aspects. FIG. 5 illustrates long-term congestion at an intermediate IAB node in accordance with some aspects. As shown FIG. 4 (access IAB node long-term congestion) and FIG. 5 (intermediate IAB node long-term congestion), a congested IAB node may send flow control information, providing leaving feedback to the parent node and a congestion indication to the child node for following two scenarios of long-term congestion. Moreover, hop-by-hop flow control can also be triggered by receiving child node flow control feedback. [0067] Flow control leaving feedback

[0068] Flow control feedback is normally triggered due to the buffer load exceeding a predetermined level or polling received from a parent node of the IAB node. However, in long-term congestion, a congested IAB node may continue to send flow control feedback to its parent node as the buffer load may be unable to be reduced for a relatively long time. Alternatively, the parent node may incorrectly assume that the load of the child node has subsided and accordingly may attempt to increase the downlink traffic to the child node, causing another flow control feedback message to be sent from the child node to the parent node, further increasing the control traffic.

[0069] To save network resources and reduce repetitions of similar flow control feedback to the parent IAB node, flow control leaving feedback may be introduced to the congested IAB node. For example, when long-term congestion occurs in the access IAB node (e.g., the IAB node 3 in FIG. 4) or the intermediate IAB node (e.g., IAB node 2 in FIG. 5), the IAB node suffering from long-term congestion may send flow control feedback (in Release 16) to its parent nodes via a BAP control packet data unit (PDU). The flow control feedback may indicate the available buffer size per BH RLC channel or per routing ID for the congested IAB node. After sending the flow control leaving feedback, the congested IAB node may avoid sending the flow control feedback multiple times if its buffer load continues to exceed the predetermined threshold. After a predetermined time scheduling and traffic limitation, downstream traffic may be reduced at the congested IAB node, and the buffer load at the congested IAB node may be reduced to below the predetermined threshold. In response, the IAB node (e.g., IAB node 3 in FIG. 4 or IAB node 2 in FIG. 5) may send flow control leaving feedback to its parent node via a new BAP control PDU. The flow control leaving feedback may indicate that the buffer status of the (previously congested) IAB node in the list of BH RLC channel or routing ID is back to normal. The new type of BAP control PDU can be modeled in a manner similar to Figure 4 and Figure 5 in TS 38.340:

Figure 1. BAP Control PDU format for flow control leaving feedback per BH RLC Channel

Figure 2. BAP Control PDU format for flow control leaving feedback per BAP routing ID

[0070] Downstream hop-by-hop flow control triggered by receiving child node flow control feedback [0071] Series congestion to its parent nodes may occur if long-term congestion occurs at an IAB node. Thus, to save time for the parent node to react to its own congestion and avoid series congestion, the parent node of the congested IAB node may send the flow control feedback to its own parent node as soon as the feedback is received from the child node. [0072] In some embodiments, a parameter “receiving child-node flow control feedback” may be added as one of the conditions to trigger hop-by-hop flow control feedback at the congested IAB nodes. For example, in FIG. 3, after IAB node 2 receives flow control feedback from IAB node 3, IAB node 2 immediately sends flow control feedback to IAB node 1. Unlike situations in which IAB node 2 waits to send flow control feedback after its buffer load exceeds the threshold, the immediate transmission of the flow control feedback reduces the latency of flow control and can better help control the downstream traffic in the IAB node that is closer to IAB donor, the source of the downstream data.

[0073] Moreover, this series of flow control feedback can reach to the donor-DU and to the donor-CU via F1AP signalling. In this case, the donor-CU may make a decision on topology adaptation including the IAB node experiencing congestion and child IAB nodes of the congested IAB node (e.g., IAB node 3 in FIG. 4, or IAB node 2/3/4 in FIG. 5).

[0074] Congestion indication

[0075] FIG. 5 illustrates a long-term congestion scenario at intermediate IAB node 2, which may lead to packet drop. In this circumstance, both child nodes of IAB node 2, i.e., IAB node 3 and IAB node 4, may lose packets due to packet drop at IAB node 2. Meanwhile, as downstream packets are not provided to the child nodes, the resources at IAB node 3 and IAB node 4 may not be fully utilized.

[0076] Thus, a congestion indication may be sent from the parent IAB node to its child node. This can help the child IAB node to be aware of the congestion situation at its parent node, and to also be prepared to switch to another parent node via local rerouting or topology adaptation (accessing to a new parent node).

[0077] Various options exist for the child IAB to switch its parent node: [0078] Option 1 : Switching by Donor-CU

[0079] In this case, the congested IAB node directly send an Fl message to the donor-CU rather than relaying the information over BAP and via the F1AP interface between the donor DU and CU. This may permit the donor-CU to make decision on topology adaptation.

[0080] Option 2: Local rerouting at the child IAB node

[0081] In this case, if the child IAB node is configured with multiple

IAB parents, the child IAB node may perform local rerouting and switch to another parent node. That is, the child IAB node itself may make the decision to switch to the other parent node rather than relying on instructions from the donor CU.

[0082] Option 3: RRC re-establishment at the child IAB node

[0083] Similar to radio link failure (RLF), the child node can trigger

RRC re-establishment, and seek and connect to a new parent node.

[0084] Whether and when to switch to a new parent node may be decided by the child node depending on the packet loss rate, etc. The new type of BAP control PDU can be modeled as Figure 6 in TS38.340:

Figure 3. BAP Control PDU format for congestion indication

[0085] Based on above discussion, new types of BAP control PDU may be added to Table 6.3.7-1 PDU Type in TS38.340:

Table 6.3.7-1: PDU type

[0086] Accordingly, the lAB-donor CU schedules resource allocation and routes traffic fairly according to each flow’s QoS information. This permits the overall traffic to reach load balancing among different BH RLC channels.

[0087] Although an embodiment has been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader scope of the present disclosure. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof show, by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.

[0088] The subject matter may be referred to herein, individually and/or collectively, by the term “embodiment” merely for convenience and without intending to voluntarily limit the scope of this application to any single inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. [0089] In this document, the terms "a" or "an" are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of "at least one" or "one or more." In this document, the term "or" is used to refer to a nonexclusive or, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. In this document, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "including" and "comprising" are open-ended, that is, a system, UE, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0090] The Abstract of the Disclosure is provided to comply with 37 C.F.R. § 1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.

Claims

CLAIMS What is claimed is:

1. An apparatus for an Integrated Access Backhaul (IAB) node, the apparatus comprising: processing circuitry configured to: determine whether a parent IAB node is congested, a backhaul (BH) radio link control (RLC) channel to the parent IAB node having a first quality of service (QoS); encode, for transmission to a IAB donor central unit (CU) of a IAB network that contains the IAB node, a report that contains load information of the IAB node; and in response to a determination that the parent IAB node is congested and transmission of the report, reroute traffic to a new parent IAB node via a BH RLC channel that has the first QoS to load balance the IAB network; and a memory configured to store the load information.

2. The apparatus of claim 1, wherein the report includes radio resource usage, a Transport Network Layer (TNL) capacity indicator, a cell capacity class value, a hardware (HW) capacity indicator, and a number of active user equipments (UEs) served by the IAB node per BH RLC channel.

3. The apparatus of claim 1, wherein the processing circuitry is further configured to reroute the traffic to the new parent IAB node based on instructions from the IAB donor CU.

4. The apparatus of claim 1, wherein the processing circuitry is further configured to: determine a hop count and amount of data of user equipments (UEs) supported by the IAB node and descendent IAB nodes of the IAB node that have the first QoS, a Backhaul Adaptation Protocol (BAP) header of data from the descendent IAB nodes including, for each UE associated with one of the

28 descendent IAB nodes, a UE bearer identity of each UE bearer and hop count of a routing path from the UE to the IAB node; and set the UE bearers of the descendent IAB nodes to a higher priority than UE bearers of the IAB node based on the hop count in the BAP headers from the descendent IAB nodes.

5. The apparatus of claim 1, wherein the processing circuitry is further configured to: determine whether a buffer load of the IAB node has exceeded a predetermined threshold; in response to a determination that the buffer load of the IAB node has exceeded the predetermined threshold, encode a Backhaul Adaptation Protocol (BAP) packet data unit (PDU) for transmission to the parent IAB node, the BAP PDU containing flow control feedback to indicate that the buffer load of the IAB node has exceeded the predetermined threshold; after transmission of the BAP PDU containing the flow control feedback: avoid repeated transmission of the flow control feedback until the buffer load of the IAB node no longer exceeds the predetermined threshold, and in response to reception of downlink traffic, determine whether the buffer load continues to exceed the predetermined threshold; and in response to a determination that the buffer load of the IAB node does not continue to exceed the predetermined threshold, encode another BAP PDU for transmission to the parent IAB node, the other BAP PDU containing flow control leaving feedback to indicate that the buffer load of the IAB node no longer exceeds the predetermined threshold.

6. The apparatus of claim 5, wherein the BAP PDU and the other BAP PDU contains available buffer size per BH RLC channel or per BAP routing identifier (ID).

7. The apparatus of claim 1, wherein the processing circuitry is further configured to: decode, from a child IAB node, a Backhaul Adaptation Protocol (BAP) packet data unit (PDU), the BAP PDU containing flow control feedback configured to indicate that a buffer load of a descendant IAB node of the IAB node has exceeded a predetermined threshold configured by the lAB-donor CU; and in response to reception of the flow control feedback, encode receiving child-node flow control feedback for transmission to the parent IAB node, the receiving child-node flow control feedback configured to indicate that the buffer load of the descendant IAB node has exceeded the predetermined threshold.

8. The apparatus of claim 1, wherein the processing circuitry is further configured to: decode, from the parent IAB node, a Backhaul Adaptation Protocol (BAP) packet data unit (PDU), the BAP PDU containing a congestion indication that indicates a buffer load of the parent IAB node has exceeded a predetermined threshold; and in response to reception of the congestion indication, reroute the traffic to the new parent IAB node.

9. The apparatus of claim 8, wherein the processing circuitry is further configured to select the new parent node based on instructions from the IAB donor CU.

10. The apparatus of claim 8, wherein the processing circuitry is further configured to select the new parent node based on local rerouting at the IAB node.

11. The apparatus of claim 8, wherein the processing circuitry is further configured to select the other parent node through initiation of radio resource control (RRC) re-establishment to connect to the new parent node.

12. The apparatus of claim 1, wherein the processing circuitry is further configured to communicate congestion information through a Backhaul Adaptation Protocol (BAP) packet data unit (PDU), the BAP PDU having a PDU type field having a value selected from among: a first value for transmission of the BAP PDU to the parent IAB node, the first value configured to provide flow control leaving feedback per BH RLC channel to indicate that a buffer load of the IAB node for the BH RLC channel no longer exceeds a predetermined threshold, a second value for transmission of the BAP PDU to the parent IAB node, the second value configured to provide flow control leaving feedback flow control leaving feedback per BAP routing identifier (ID) to indicate that a buffer load of the IAB node for the BAP routing ID no longer exceeds the predetermined threshold, and a third value for reception of the BAP PDU from the parent node, the third value configured to provide a congestion indication that indicates congestion of the parent IAB node.

13. An apparatus for an Integrated Access Backhaul (IAB) node, the apparatus comprising: processing circuitry configured to: determine, based on a Backhaul Adaptation Protocol (BAP) packet data unit (PDU), whether at least one of a parent IAB node of the IAB node or a child IAB node of the IAB node is congested; in response to a determination that the parent IAB node is congested, select a new parent IAB node for communication to an IAB donor central unit (CU) of a IAB network that contains the IAB node, a quality of service (QoS) of a backhaul (BH) radio link control (RLC) channel to the new parent IAB node being the same as the parent IAB node; and in response to a determination that the child IAB node is congested, at least limit transmission to the child IAB node until after reception from the child IAB node of flow control leaving feedback that indicates the child IAB node is no longer congested; and a memory configured to store the BAP PDU.

14. The apparatus of claim 13, wherein the processing circuitry is further configured to: determine that the IAB node is congested; and in response to a determination that the IAB node is congested, encode an indication of congestion of the IAB node to the IAB donor CU directly through an F1AP interface via multiple hops of IAB nodes.

15. The apparatus of claim 13, wherein the processing circuitry is further configured to select the new parent node based on local rerouting at the IAB node without instructions from the IAB donor CU.

16. The apparatus of claim 13, wherein the processing circuitry is further configured to: determine a hop count and amount of data of user equipments (UEs) supported by the IAB node and descendent IAB nodes of the IAB node that have the QoS, a BAP header of data from the descendent IAB nodes including, for each UE associated with one of the descendent IAB nodes, a UE bearer identity of each UE bearer and hop count of a routing path from the UE to the IAB node; and set the UE bearers of the descendent IAB nodes to a higher priority than UE bearers of the IAB node based on the hop count in the BAP headers from the descendent IAB nodes.

17. The apparatus of claim 13, wherein the BAP PDU has a PDU type field having a value selected from among: a first value for transmission of the BAP PDU to the parent IAB node, the first value configured to provide flow control leaving feedback per BH RLC channel to indicate that a buffer load of the IAB node for the BH RLC channel no longer exceeds a predetermined threshold, a second value for transmission of the BAP PDU to the parent IAB node, the second value configured to provide flow control leaving feedback flow control leaving feedback per BAP routing identifier (ID) to indicate that a buffer

32 load of the IAB node for the BAP routing ID no longer exceeds the predetermined threshold, and a third vale for reception of the BAP PDU from the parent node, the third value configured to provide a congestion indication that indicates congestion of the parent IAB node.

18. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors of Integrated Access Backhaul (IAB) node, the one or more processors to configure the IAB node to, when the instructions are executed: determine, based on a Backhaul Adaptation Protocol (BAP) packet data unit (PDU), whether at least one of a parent IAB node of the IAB node or a child IAB node of the IAB node is congested; in response to a determination that the parent IAB node is congested, select a new parent IAB node for communication to an IAB donor central unit (CU) of a IAB network that contains the IAB node, a quality of service (QoS) of a backhaul (BH) radio link control (RLC) channel to the new parent IAB node being the same as the parent IAB node; and in response to a determination that the child IAB node is congested, at least limit transmission to the child IAB node until after reception from the child IAB node of flow control leaving feedback that indicates the child IAB node is no longer congested.

19. The medium of claim 18, wherein the instructions, when executed, further cause the one or more processors to configure the IAB node to: determine a hop count and amount of data of user equipments (UEs) supported by the IAB node and descendent IAB nodes of the IAB node that have the QoS, a BAP header of data from the descendent IAB nodes including, for each UE associated with one of the descendent IAB nodes, a UE bearer identity of each UE bearer and hop count of a routing path from the UE to the IAB node; and set the UE bearers of the descendent IAB nodes to a higher priority than UE bearers of the IAB node based on the BAP headers from the descendent IAB nodes.

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20. The medium of claim 18, wherein the BAP PDU has a PDU type field having a value selected from among: a first value for transmission of the BAP PDU to the parent IAB node, the first value configured to provide flow control leaving feedback per BH RLC channel to indicate that a buffer load of the IAB node for the BH RLC channel no longer exceeds a predetermined threshold, a second value for transmission of the BAP PDU to the parent IAB node, the second value configured to provide flow control leaving feedback flow control leaving feedback per BAP routing identifier (ID) to indicate that a buffer load of the IAB node for the BAP routing ID no longer exceeds the predetermined threshold, and a third vale for reception of the BAP PDU from the parent node, the third value configured to provide a congestion indication that indicates congestion of the parent IAB node.

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