Patent Publication Number: US-2021194657-A1

Title: Techniques for quasi co-location (qcl) indication in an integrated access and backhaul (iab) system

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of U.S. Provisional Application Ser. No. 62/951,917, entitled “TECHNIQUES FOR QUASI CO-LOCATION (QCL) INDICATION IN AN INTEGRATED ACCESS AND BACKHAUL (IAB) SYSTEM” and filed on Dec. 20, 2019, which is expressly incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to bi-direction preemption indication transmissions. 
     Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems, and single-carrier frequency division multiple access (SC-FDMA) systems. 
     These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. For example, a fifth generation (5G) wireless communications technology (which can be referred to as NR) is envisaged to expand and support diverse usage scenarios and applications with respect to current mobile network generations. In an aspect, 5G communications technology can include: enhanced mobile broadband addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable-low latency communications (URLLC) with certain specifications for latency and reliability; and massive machine type communications, which can allow a very large number of connected devices and transmission of a relatively low volume of non-delay-sensitive information. 
     For example, for various communications technology such as, but not limited to NR, full duplex communication with respect to integrated access and backhaul (IAB) implementations may increase transmission speed and flexibility but also transmission complexity. Thus, improvements in wireless communication operations may be desired. 
     SUMMARY 
     The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later. 
     According to an example, a method of wireless communication at an integrated access and backhaul (IAB) node is provided. The method may include determining a spatial relation between a first communication of a distributed unit (DU) entity and a second communication of one of the DU entity or a co-located mobile termination (MT) entity, configuring a beam of at least one of the MT or the DU based on the determined spatial relation, and communicating using the beam with at least one entity. 
     A further example implementation includes an apparatus for wireless communications comprising a memory and at least one processor in communication with the memory. The at least one processor may be configured to determine a spatial relation between a first communication of a DU entity and a second communication of one of the DU entity or a co-located MT entity. The at least one processor may further be configured to configure a beam of at least one of the MT or the DU based on the determined spatial relation. The at least one processor may be configured to communicate using the beam with at least one entity. 
     An additional example implementation includes an apparatus for wireless communications. The apparatus may include means for determining a spatial relation between a first communication of a DU entity and a second communication of one of the DU entity or a co-located MT entity. The apparatus may further include means for configuring a beam of at least one of the MT or the DU based on the determined spatial relation. The apparatus may further include means for communicating using the beam with at least one entity. 
     A further example implementation includes computer-readable medium storing computer code executable by a processor for wireless communications at a network entity comprising code for determining a spatial relation between a first communication of a DU entity and a second communication of one of the DU entity or a co-located MT entity, configuring a beam of at least one of the MT or the DU based on the determined spatial relation, and communicating using the beam with at least one entity. 
     For example, determining the spatial relation may include determining that an uplink transmission of the MT entity is spatially related to a downlink transmission of the DU entity. In some aspects, configuring the beam includes configuring the uplink transmission of the MT entity with a spatial relation information indication including at least one of a synchronization signal block (SSB) index associated with the DU entity, or a channel state information reference signal (CSI-RS) index associated with the DU entity. 
     In some aspects, at least one of the SSB index or the CSI-RS index may be associated with different transmission reception points (TRPs) of the DU entity. 
     In some aspects, the spatial relation information indication further includes an index of an SSB transmitted by the DU entity within an SSB transmission configuration (STC) window. 
     In some aspects, the index of the SSB corresponds to at least one of a first SSB index with a center frequency or a second SSB index with an STC configuration window. 
     For example, determining the spatial relation may include determining that a downlink reception of the MT entity is spatially related to a downlink transmission of the DU entity. In some aspects, configuring the beam includes configuring the downlink transmission of the MT entity with a spatial relation information indication including at least one of a SSB index associated with the DU entity, or a CSI-RS index associated with the DU entity. 
     In some aspects, at least one of the SSB index or the CSI-RS index may be associated with different TRPs of the DU entity. 
     In some aspects, the spatial relation information indication further includes an index of an SSB transmitted by the DU entity within an SSB transmission configuration (STC) window. 
     For example, determining the spatial relation may include determining that a first downlink transmission of the DU entity is spatially related to a second downlink transmission of the DU entity or an uplink transmission of the MT entity. In some aspects, configuring the beam includes configuring the first downlink transmission of the DU entity with a spatial relation information indication including at least one of a SSB index associated with the DU entity, or a CSI-RS index associated with the DU entity. 
     In some aspects, the spatial relation includes receiving a beam configuration indication from a central unit (CU) or a parent IAB entity. 
     In some aspects, at least one of the SSB index or the CSI-RS index are associated with different TRPs of the DU entity. 
     In some aspects, the spatial relation information indication further includes at least one of an index of an SSB transmitted by the DU entity within an STC window 
     In some aspects, configuring the beam may include configuring the downlink transmission of the DU entity with a spatial relation information indication including a sounding reference signal (SRS) index of the MT entity. 
     For example, determining the spatial relation may include determining that an uplink reception of the DU entity is spatially related to a downlink transmission of the DU entity or an uplink transmission of the MT entity. In some aspects, configuring the beam includes configuring the uplink reception of the DU entity with a spatial relation information indication including at least one of a SSB index associated with the DU entity, or a CSI-RS index associated with the DU entity. 
     In some aspects, determining the spatial relation may include receiving a beam configuration indication from a CU or a parent IAB entity. 
     In some aspects, at least one of the SSB index or the CSI-RS index may be associated with different TRPs of the DU entity. 
     In some aspects, the spatial relation information indication further includes at least one of an index of an SSB transmitted by the DU entity within an STC window. 
     In some aspects, configuring the beam may include configuring the downlink transmission of the DU entity with a spatial relation information indication including a sounding reference signal (SRS) index of the MT entity. 
     In some aspects, the spatial relation may correspond to a quasi-co-location of the MT entity and the DU entity. 
     In some aspects, communicating using the beam with at least one entity comprises at least one of the following an uplink transmission by the MT entity, a downlink reception by the MT entity, a downlink transmission by the DU entity, an uplink reception by the DU entity, or measuring one or more signals by one of the MT or DU entities. 
     To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements, and in which: 
         FIG. 1  illustrates an example of a wireless communication system, in accordance with various aspects of the present disclosure; 
         FIG. 2  is a block diagram illustrating an example of a network entity (also referred to as a base station), in accordance with various aspects of the present disclosure; 
         FIG. 3  is a block diagram illustrating an example of a user equipment (UE), in accordance with various aspects of the present disclosure; 
         FIG. 4  is a diagram of an example integrated access and backhaul (IAB) system, in accordance with various aspects of the present disclosure; 
         FIG. 5  is a flow chart illustrating an example of a method for wireless communications at a node such as an IAB node in accordance with various aspects of the present disclosure; 
         FIG. 6  is a flow chart illustrating an example of a method for wireless communications at a node such as an IAB node in accordance with various aspects of the present disclosure; and 
         FIG. 7  is a block diagram illustrating an example of a MIMO communication system including a base station and a UE, in accordance with various aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Various aspects are now described with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. It may be evident, however, that such aspect(s) may be practiced without these specific details. 
     The described features generally relate to quasi co-location (QCL) indications in an integrated access and backhaul (IAB) system. Specifically, base stations may include a backhaul interface for communication with a backhaul portion of the network. The backhaul may provide a link between a base station and a core network, and in some examples, the backhaul may provide interconnection between the respective base stations. The core network is a part of a wireless communication system that is generally independent of the radio access technology used in the radio access network. Various types of backhaul interfaces may be employed, such as a direct physical connection, a virtual network, or the like using any suitable transport network. Some base stations may be configured as IAB nodes, where the wireless spectrum may be used both for access links (i.e., wireless links with user equipments (UEs)), and for backhaul links, which may be referred to as wireless self-backhauling. By using wireless self-backhauling, rather than requiring each new base station deployment to be outfitted with its own hard-wired backhaul connection, the wireless spectrum utilized for communication between the base station and UE may be leveraged for backhaul communication, enabling fast and easy deployment of highly dense small cell networks. 
     With respect to QCL, two antenna ports may be considered QCLed if properties of the channel over which a symbol on one antenna port is conveyed can be inferred from the channel over which a symbol on the other antenna port is conveyed. That is, in some aspects, transmissions or receptions from two channels may share similar channel conditions. Accordingly, channel information estimated to detect one channel may assist with detecting the other spatially related channel. As such, it would be desirable to implement such techniques to an JAB system. Specifically, an IAB-node may have one or more mobile terminations (MTs), and one or more distributed units (DUs) (e.g., and each DU has one or more cells/sectors). Each entity (MT and/or cell) may also have one or more transmission/reception points (TRPs). The signals that are transmitted by/received by different entities (e.g., or their TRPs) may be quasi co-located and/or spatially related. 
     In one implementation, an IAB node may determine a spatial relation between a first communication of a DU entity and a second communication of one of the DU entity or a co-located MT entity. The IAB node may further configure a beam of at least one of the MT or the DU based on the determined spatial relation. The JAB node may further communicate using the beam with at least one entity. 
     The described features will be presented in more detail below with reference to  FIGS. 1-7 . 
     As used in this application, the terms “component,” “module,” “system” and the like are intended to include a computer-related entity, such as but not limited to hardware, software, a combination of hardware and software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component can be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components can communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets, such as data from one component interacting with another component in a local system, distributed system, and/or across a network such as the Internet with other systems by way of the signal. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. 
     Techniques described herein may be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms “system” and “network” may often be used interchangeably. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0 and A are commonly referred to as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1×EV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM™, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies, including cellular (e.g., LTE) communications over a shared radio frequency spectrum band. The description below, however, describes an LTE/LTE-A system for purposes of example, and LTE terminology is used in much of the description below, although the techniques are applicable beyond LTE/LTE-A applications (e.g., to fifth generation (5G) NR networks or other next generation communication systems). 
     The following description provides examples, and is not limiting of the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in other examples. 
     Various aspects or features will be presented in terms of systems that can include a number of devices, components, modules, and the like. It is to be understood and appreciated that the various systems can include additional devices, components, modules, etc. and/or may not include all of the devices, components, modules etc. discussed in connection with the figures. A combination of these approaches can also be used. 
       FIG. 1  is a diagram illustrating an example of a wireless communications system and an access network  100 . The wireless communications system (also referred to as a wireless wide area network (WWAN)) can include base stations  102 , UEs  104 , an Evolved Packet Core (EPC)  160 , and/or a 5G Core (5GC)  190 . The base stations  102 , which may also be referred to as network entities, may include macro cells (high power cellular base station) and/or small cells (low power cellular base station). The macro cells can include base stations. The small cells can include femtocells, picocells, and microcells. In an example, the base stations  102  may also include gNBs  180 , as described further herein. 
     In one example, some nodes acting as an IAB node, such as base station  102 /gNB  180 , may have a modem  240  and communicating component  242  for configuring one or more beams based on QCL indications, as described herein. Though a base station  102 /gNB  180  is shown as having the modem  240  and communicating component  242 , this is one illustrative example, and substantially any node or type of node acting as an IAB node may include a modem  240  and communicating component  242  for providing corresponding functionalities described herein. 
     The base stations  102  configured for 4G LTE (which can collectively be referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC  160  through backhaul links  132  (e.g., using an Sl interface). The base stations  102  configured for 5G NR (which can collectively be referred to as Next Generation RAN (NG-RAN)) may interface with 5GC  190  through backhaul links  184 . In addition to other functions, the base stations  102  may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations  102  may communicate directly or indirectly (e.g., through the EPC  160  or 5GC  190 ) with each other over backhaul links  134  (e.g., using an X2 interface). The backhaul links  132 ,  134  and/or  184  may be wired or wireless. 
     The base stations  102  may wirelessly communicate with one or more UEs  104 . Each of the base stations  102  may provide communication coverage for a respective geographic coverage area  110 . There may be overlapping geographic coverage areas  110 . For example, the small cell  102 ′ may have a coverage area  110 ′ that overlaps the coverage area  110  of one or more macro base stations  102 . A network that includes both small cell and macro cells may be referred to as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs), which may provide service to a restricted group, which can be referred to as a closed subscriber group (CSG). The communication links  120  between the base stations  102  and the UEs  104  may include uplink (UL) (also referred to as reverse link) transmissions from a UE  104  to a base station  102  and/or downlink (DL) (also referred to as forward link) transmissions from a base station  102  to a UE  104 . The communication links  120  may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base stations  102 /UEs  104  may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (e.g., for x component carriers) used for transmission in the DL and/or the UL direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL). The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell). 
     In another example, certain UEs  104  may communicate with each other using 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 communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR. 
     The wireless communications system may further include a Wi-Fi access point (AP)  150  in communication with Wi-Fi stations (STAs)  152  via communication links  154  in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs  152 /AP  150  may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available. 
     The small cell  102 ′ may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell  102 ′ may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP  150 . The small cell  102 ′, employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network. 
     A base station  102 , whether a small cell  102 ′ or a large cell (e.g., macro base station), may include an eNB, gNodeB (gNB), or other type of base station. Some base stations, such as gNB  180  may operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and/or near mmW frequencies in communication with the UE  104 . When the gNB  180  operates in mmW or near mmW frequencies, the gNB  180  may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW/near mmW radio frequency band has extremely high path loss and a short range. The mmW base station  180  may utilize beamforming  182  with the UE  104  to compensate for the extremely high path loss and short range. A base station  102  referred to herein can include a gNB  180 . 
     The EPC  160  may include a Mobility Management Entity (MME)  162 , other MMEs  164 , a Serving Gateway  166 , a Multimedia Broadcast Multicast Service (MBMS) Gateway  168 , a Broadcast Multicast Service Center (BM-SC)  170 , and a Packet Data Network (PDN) Gateway  172 . The MME  162  may be in communication with a Home Subscriber Server (HSS)  174 . The MME  162  is the control node that processes the signaling between the UEs  104  and the EPC  160 . Generally, the MME  162  provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway  166 , which itself is connected to the PDN Gateway  172 . The PDN Gateway  172  provides UE IP address allocation as well as other functions. The PDN Gateway  172  and the BM-SC  170  are connected to the IP Services  176 . The IP Services  176  may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, and/or other IP services. The BM-SC  170  may provide functions for MBMS user service provisioning and delivery. The BM-SC  170  may serve as an entry point for content provider MBMS transmission, 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 the 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 eMBMS related charging information. 
     The 5GC  190  may include a Access and Mobility Management Function (AMF)  192 , other AMFs  193 , a Session Management Function (SMF)  194 , and a User Plane Function (UPF)  195 . The AMF  192  may be in communication with a Unified Data Management (UDM)  196 . The AMF  192  can be a control node that processes the signaling between the UEs  104  and the 5GC  190 . Generally, the AMF  192  can provide QoS flow and session management. User Internet protocol (IP) packets (e.g., from one or more UEs  104 ) can be transferred through the UPF  195 . The UPF  195  can provide UE IP address allocation for one or more UEs, as well as other functions. The UPF  195  is connected to the IP Services  197 . The IP Services  197  may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, and/or other IP services. 
     The base station may also be referred to as a gNB, Node B, evolved Node B (eNB), an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit reception point (TRP), or some other suitable terminology. The base station  102  provides an access point to the EPC  160  or 5GC  190  for a UE  104 . Examples of UEs  104  include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a positioning system (e.g., satellite, terrestrial), a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, a smart device, robots, drones, an industrial/manufacturing device, a wearable device (e.g., a smart watch, smart clothing, smart glasses, virtual reality goggles, a smart wristband, smart jewelry (e.g., a smart ring, a smart bracelet)), a vehicle/a vehicular device, a meter (e.g., parking meter, electric meter, gas meter, water meter, flow meter), a gas pump, a large or small kitchen appliance, a medical/healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs  104  may be referred to as IoT devices (e.g., meters, pumps, monitors, cameras, industrial/manufacturing devices, appliances, vehicles, robots, drones, etc.). IoT UEs may include MTC/enhanced MTC (eMTC, also referred to as CAT-M, Cat M1) UEs, NB-IoT (also referred to as CAT NB1) UEs, as well as other types of UEs. In the present disclosure, eMTC and NB-IoT may refer to future technologies that may evolve from or may be based on these technologies. For example, eMTC may include FeMTC (further eMTC), eFeMTC (enhanced further eMTC), mMTC (massive MTC), etc., and NB-IoT may include eNB-IoT (enhanced NB-IoT), FeNB-IoT (further enhanced NB-IoT), etc. The UE  104  may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. 
     Turning now to  FIGS. 2-5 , aspects are depicted with reference to one or more components and one or more methods that may perform the actions or operations described herein, where aspects in dashed line may be optional. Although the operations described below in  FIGS. 4 and 5  are presented in a particular order and/or as being performed by an example component, it should be understood that the ordering of the actions and the components performing the actions may be varied, depending on the implementation. Moreover, it should be understood that the following actions, functions, and/or described components may be performed by a specially-programmed processor, a processor executing specially-programmed software or computer-readable media, or by any other combination of a hardware component and/or a software component capable of performing the described actions or functions. 
     Referring to  FIG. 2 , one example of an implementation of a node acting as an IAB node, such as base station  102  (e.g., a base station  102  and/or gNB  180 , as described above) may include a variety of components, some of which have already been described above and are described further herein, including components such as one or more processors  212  and memory  216  and transceiver  202  in communication via one or more buses  244 , which may operate in conjunction with modem  240  and/or communicating component  242  for beam configurations based on QCL indications. 
     In an aspect, the one or more processors  212  can include a modem  240  and/or can be part of the modem  240  that uses one or more modem processors. Thus, the various functions related to communicating component  242  may be included in modem  240  and/or processors  212  and, in an aspect, can be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors  212  may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiver processor, or a transceiver processor associated with transceiver  202 . In other aspects, some of the features of the one or more processors  212  and/or modem  240  associated with communicating component  242  may be performed by transceiver  202 . 
     Also, memory  216  may be configured to store data used herein and/or local versions of applications  275  or communicating component  242  and/or one or more of its subcomponents being executed by at least one processor  212 . Memory  216  can include any type of computer-readable medium usable by a computer or at least one processor  212 , such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory  216  may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining communicating component  242  and/or one or more of its subcomponents, and/or data associated therewith, when base station  102  is operating at least one processor  212  to execute communicating component  242  and/or one or more of its subcomponents. 
     Transceiver  202  may include at least one receiver  206  and at least one transmitter  208 . Receiver  206  may include hardware and/or software executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). Receiver  206  may be, for example, a radio frequency (RF) receiver. In an aspect, receiver  206  may receive signals transmitted by at least one base station  102 . Additionally, receiver  206  may process such received signals, and also may obtain measurements of the signals, such as, but not limited to, Ec/Io, signal-to-noise ratio (SNR), reference signal received power (RSRP), received signal strength indicator (RSSI), etc. Transmitter  208  may include hardware and/or software executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). A suitable example of transmitter  208  may including, but is not limited to, an RF transmitter. 
     Moreover, in an aspect, base station  102  may include RF front end  288 , which may operate in communication with one or more antennas  265  and transceiver  202  for receiving and transmitting radio transmissions, for example, wireless communications transmitted by at least one base station  102  or wireless transmissions transmitted by UE  104 . RF front end  288  may be connected to one or more antennas  265  and can include one or more low-noise amplifiers (LNAs)  290 , one or more switches  292 , one or more power amplifiers (PAs)  298 , and one or more filters  296  for transmitting and receiving RF signals. The antennas  265  may include one or more antennas, antenna elements, and/or antenna arrays. 
     In an aspect, LNA  290  can amplify a received signal at a desired output level. In an aspect, each LNA  290  may have a specified minimum and maximum gain values. In an aspect, RF front end  288  may use one or more switches  292  to select a particular LNA  290  and its specified gain value based on a desired gain value for a particular application. 
     Further, for example, one or more PA(s)  298  may be used by RF front end  288  to amplify a signal for an RF output at a desired output power level. In an aspect, each PA  298  may have specified minimum and maximum gain values. In an aspect, RF front end  288  may use one or more switches  292  to select a particular PA  298  and its specified gain value based on a desired gain value for a particular application. 
     Also, for example, one or more filters  296  can be used by RF front end  288  to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, a respective filter  296  can be used to filter an output from a respective PA  298  to produce an output signal for transmission. In an aspect, each filter  296  can be connected to a specific LNA  290  and/or PA  298 . In an aspect, RF front end  288  can use one or more switches  292  to select a transmit or receive path using a specified filter  296 , LNA  290 , and/or PA  298 , based on a configuration as specified by transceiver  202  and/or processor  212 . 
     As such, transceiver  202  may be configured to transmit and receive wireless signals through one or more antennas  265  via RF front end  288 . In an aspect, transceiver may be tuned to operate at specified frequencies such that UE  104  can communicate with, for example, one or more base stations  102  or one or more cells associated with one or more base stations  102 . In an aspect, for example, modem  240  can configure transceiver  202  to operate at a specified frequency and power level based on the UE configuration of the UE  104  and the communication protocol used by modem  240 . 
     In an aspect, modem  240  can be a multiband-multimode modem, which can process digital data and communicate with transceiver  202  such that the digital data is sent and received using transceiver  202 . In an aspect, modem  240  can be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, modem  240  can be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, modem  240  can control one or more components of UE  104  (e.g., RF front end  288 , transceiver  202 ) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In an aspect, the modem configuration can be based on the mode of the modem and the frequency band in use. In another aspect, the modem configuration can be based on UE configuration information associated with UE  104  as provided by the network during cell selection and/or cell reselection. 
     In an aspect, the processor(s)  212  may correspond to one or more of the processors described in connection with the UE in  FIG. 7 . Similarly, the memory  216  may correspond to the memory described in connection with the UE in  FIG. 7 . 
     Referring to  FIG. 3 , one example of an implementation of UE  104  may include a variety of components, some of which have already been described above and are described further herein, including components such as one or more processors  312  and memory  316  and transceiver  302  in communication via one or more buses  344 , which may operate in conjunction with modem  340 . 
     The transceiver  302 , receiver  306 , transmitter  308 , one or more processors  312 , memory  316 , applications  375 , buses  344 , RF front end  388 , LNAs  390 , switches  392 , filters  396 , PAs  398 , and one or more antennas  365  may be the same as or similar to the corresponding components of base station  102 , as described above, but configured or otherwise programmed for base station operations as opposed to base station operations. 
     In an aspect, the processor(s)  312  may correspond to one or more of the processors described in connection with the base station in  FIG. 7 . Similarly, the memory  316  may correspond to the memory described in connection with the base station in  FIG. 7 . 
     Further,  FIG. 4  is a diagram of an uplink and downlink communication scheme in an IAB system  400 , as described herein. In one example, the IAB system  400  may include an IAB node  404 , which may be similar to or the same as the base station  102 . The IAB system  400  may further include a parent node  402 , a child node  406 , and a UE  104 . For example, in an IAB system, an IAB node  404  can transmit uplink data towards the parent-node  402 , and receive the uplink data from the UE  104  and/or child node  406 . The IAB node  404  may also transmit downlink data towards the child node  406 , and receive the downlink data from the parent node  402 . 
     In some aspects, the IAB node  404  may host two NR functions: (i) a MT  408 , used to maintain the wireless backhaul connection towards an upstream IAB-node or IAB-donor, and (ii) a DU  410  to provide access connection to the UEs or the downstream MTs of other IAB-nodes. The DU  410  may connect to a CU hosted by the IAB-donor by means of the NR F1 interface running over the wireless backhaul link. Therefore, in the access of IAB nodes and donors there may be a coexistence of two interfaces, i.e., the Uu interface (e.g., between the UEs and the DU of the gNBs) and the aforementioned F1 interface. 
     The IAB node  404  may include the communicating component  242 , which may be configured to determine a spatial relation between a first communication of a DU  410  entity and a second communication of one of the DU entity or a co-located MT  408  entity. The IAB node  404  may further configure a beam of at least one of the MT  408  or the DU  410  based on the determined spatial relation, and communicate using the beam with at least one entity. 
     The various nodes may communicate using a number of communication channels. For example, for a physical downlink control channel (PDCCH), a QCL may be configured for each control resource set (CORESET). In one aspect, QCL may be configured via a transmission configuration indicator (TCI) state such as when a radio resource control (RRC) configures multiple TCI states for each CORESET, such that a media access control (MAC) indicates which TCI state is activated. In another aspect, if no QCL is configured, the CORESET may be determined to be QCLed with a synchronization signal block (SSB). 
     In another example, for a physical downlink shared channel (PDSCH), a demodulation reference signal (DMRS) for PDSCH, and for PDSCH using the same precoding may be implemented. The downlink control information (DCI) may be indicate TCI state (i.e., one out of ‘M’ configured states). TCI may indicate QCL relation between DMRS of PDSCH (i.e., DMRS port groups) and channel state information reference signal (CSI-RS) or SSB. If the TCI does not indicate the QCL relation or if a scheduling offset (i.e., between PDCCH and PDSCH) is less than ‘N’ slots, then the same TCI state as the DCI may be determined. 
     In a further example, for a physical uplink control channel, an indicator such as spatialRelatoinInfo, which may be QCLed with SSB, CSI-RS or SRS may be provided. In another example, for a physical uplink shared channel, a DMRS for PUSCH and PUSCH using the same precoding may be implemented. Additionally, PUSCH may be provided with codebook-based precoding such that a DCI provides precoding information and antenna ports (i.e., antenna port of a configured SRS) via scheduling request indicator (SRI). For non-codebook-based implementations, the same precoding device may be used for a configured SRS (i.e., indicated via SRI). 
     A sounding reference signal (SRS) may be transmitted on the uplink. For instance, a spatialRelationInfo may be a reference signal corresponding to an SSB, CSI-RS, or SRS. If the SRS is periodic, the reference CSI-RS may be periodic or semi-persistent. In this case, the reference SRS may be periodic. If the SRS is semi-persistent, the CSI-RS may be periodic or semi-persistent. In this case, the reference SRS may be periodic or semi-persistent. If the SRS is aperiodic, the CSI-RS may be periodic or semi-persistent. In this case, the reference SRS may be periodic, semi-persistent, or aperiodic. If no spatialRelationInfo is provided, then the UE may sweep multiple uplink beam directions. 
     The present aspects provide implementations for QCL indications in IAB systems. Specifically, an IAB-node may have one or more MTs, and one or more DUs, where each DU may have one or more cells/sectors. Each entity (i.e., MT and/or cell) may also have one or more TRPs. The signals that are transmitted by or received by different entities (i.e., or their TRPs) may be QCLed and/or spatially related. 
     In some aspects, a number of QCL indications may be provided. For example, QCL Type-A may indicate a Doppler shift, Doppler spread, average delay, and a delay spread. QCL Type-B may indicate a Doppler shift and Doppler spread. QCL Type-C may indicate a Doppler shift and average delay. QCL Type-D may indicate a spatial reception parameter. 
     In one example, a transmission (i.e., uplink) of an IAB-node MT may be spatially related to transmissions (i.e., downlink) of a collocated IAB-node DU cell. An uplink transmission may be configured with a spatialRelationInfo that provides an SSB-index and a CSI-RS-index of a collocated IAB-node DU cell. In some aspects, the configuration may be extendable to different TRPs of the cell (e.g., TRP index may be indicated in this case). An uplink transmission may further be configured with an spatialRelationInfo that provides an index of an SSB transmitted by a collocated IAB-node DU cell within an SSB transmission configuration (STC) window, which may be indicated based on an SSB index along with a center frequency or an SSB index along with an STC configuration index. 
     In a further example, a reception (i.e., downlink) of an IAB-node MT may be spatially related, or QCLed, to transmissions of a collocated IAB-node DU cell. An MT may be configured to receive a downlink signal or perform a measurement using a beam/precoding that may be used for transmission/reception of other communications. In some aspects, an SSB-index and CSI-RS-index of a collocated IAB-node DU cell may be indicated, and may be extendable to different TRPs of cell (e.g., TRP index may be indicated in this case). Further, an index of an SSB transmitted by a collocated IAB-node DU cell within an STC window may be provided. 
     In another example, a DU cell may be configured (e.g., by a CU or a parent-node) to transmit a downlink signal using a beam/precoding that may be used for transmission/reception of other communications. In some aspects, an SSB-index and CSI-RS-index of the DU cell may be provided, and may be extendable to different TRPs of cell (i.e., TRP index may be indicated). An index of an SSB transmitted by the cell within an STC window may also be implemented. Further, an SRS-index of a collocated MT may be provided and may be extendable to different TRPs of the MT. 
     In a further example, a DU cell may be configured (e.g., by a CU or a parent-node) to receive an uplink signal or perform a measurement using a beam/precoding that may be used for transmission/reception of other communications. In some aspects, an SSB-index, CSI-RS-index of the DU cell may be determined and extendable to different TRPs of cell (TRP index indicated). Additionally, an index of an SSB transmitted by the cell within an STC window may be determined, as well as an SRS-index of a collocated MT. 
     Turning now to  FIGS. 5 and 6 , aspects are depicted with reference to one or more components and one or more methods that may perform the actions or operations described herein, where aspects in dashed line may be optional. Although the operations described below in  FIGS. 5 and 6  are presented in a particular order and/or as being performed by an example component, it should be understood that the ordering of the actions and the components performing the actions may be varied, depending on the implementation. Moreover, it should be understood that the following actions, functions, and/or described components may be performed by reference to one or more components of  FIGS. 1, 2, 4 and/or 7 , as described herein, a specially-programmed processor, a processor executing specially-programmed software or computer-readable media, or by any other combination of a hardware component and/or a software component capable of performing the described actions or functions. 
       FIGS. 5 and 6  illustrate a flow chart of an example of a method  500  for wireless communication at a node, which may be an IAB node. In an example, a base station  102  can perform the functions described in method  500  using one or more of the components described in  FIGS. 1, 2, 4, and 7 . 
     At block  502 , the method  500  may determine a spatial relation between a first communication of a DU entity and a second communication of one of the DU entity or a co-located MT entity. In an aspect, the communicating component  242 , e.g., in conjunction with processor(s)  212 , memory  216 , and/or transceiver  202 , may be configured to determine a spatial relation between a first communication of a DU entity and a second communication of one of the DU entity or a co-located MT entity. In one example, the data can be associated with a priority level. Thus, the base station  102 , the processor(s)  212 , the communicating component  242  or one of its subcomponents may define the means for determining a spatial relation between a first communication of a DU entity and a second communication of one of the DU entity or a co-located MT entity. In some aspects, as further described below, block  402  may continue to block  602  ( FIG. 6 ). 
     At block  504 , the method  500  may configure a beam of at least one of the MT or the DU based on the determined spatial relation. In an aspect, the communicating component  242 , e.g., in conjunction with processor(s)  212 , memory  216 , and/or transceiver  202 , may be configured to configure a beam of at least one of the MT or the DU based on the determined spatial relation. Thus, the base station  102 , the processor(s)  212 , the communicating component  242  or one of its subcomponents may define the means for configuring a beam of at least one of the MT or the DU based on the determined spatial relation. 
     At block  506 , the method  500  may communicate using the beam with at least one entity. In an aspect, the communicating component  242 , e.g., in conjunction with processor(s)  212 , memory  216 , and/or transceiver  202 , may be configured to communicate using the beam with at least one entity. Thus, the base station  102 , the processor(s)  212 , the communicating component  242  or one of its subcomponents may define the means for communicating using the beam with at least one entity. 
     At block  602 , determination of the spatial relation may correspond to any one of blocks  604 ,  606 ,  608 , or  610 . 
     For example, at block  604 , determining the spatial relation may include determining that an uplink transmission of the MT entity is spatially related to a downlink transmission of the DU entity. In some aspects, configuring the beam includes configuring the uplink transmission of the MT entity with a spatial relation information indication including at least one of a synchronization signal block (SSB) index associated with the DU entity, or a channel state information reference signal (CSI-RS) index associated with the DU entity. 
     In some aspects, at least one of the SSB index or the CSI-RS index may be associated with different transmission reception points (TRPs) of the DU entity. 
     In some aspects, the spatial relation information indication further includes an index of an SSB transmitted by the DU entity within an SSB transmission configuration (STC) window. 
     In some aspects, the index of the SSB corresponds to at least one of a first SSB index with a center frequency or a second SSB index with an STC configuration window. 
     For example, at block  606 , determining the spatial relation may include determining that a downlink reception of the MT entity is spatially related to a downlink transmission of the DU entity. In some aspects, configuring the beam includes configuring the downlink transmission of the MT entity with a spatial relation information indication including at least one of a SSB index associated with the DU entity, or a CSI-RS index associated with the DU entity. 
     In some aspects, at least one of the SSB index or the CSI-RS index may be associated with different TRPs of the DU entity. 
     In some aspects, the spatial relation information indication further includes an index of an SSB transmitted by the DU entity within an SSB transmission configuration (STC) window. 
     For example, at block  608 , determining the spatial relation may include determining that a first downlink transmission of the DU entity is spatially related to a second downlink transmission of the DU entity or an uplink transmission of the MT entity. In some aspects, configuring the beam includes configuring the first downlink transmission of the DU entity with a spatial relation information indication including at least one of a SSB index associated with the DU entity, or a CSI-RS index associated with the DU entity. 
     In some aspects, the spatial relation includes receiving a beam configuration indication from a central unit (CU) or a parent IAB entity. 
     In some aspects, at least one of the SSB index or the CSI-RS index are associated with different TRPs of the DU entity. 
     In some aspects, the spatial relation information indication further includes at least one of an index of an SSB transmitted by the DU entity within an STC window 
     In some aspects, configuring the beam may include configuring the downlink transmission of the DU entity with a spatial relation information indication including a sounding reference signal (SRS) index of the MT entity. 
     For example, at block  610 , determining the spatial relation may include determining that an uplink reception of the DU entity is spatially related to a downlink transmission of the DU entity or an uplink transmission of the MT entity. In some aspects, configuring the beam includes configuring the uplink reception of the DU entity with a spatial relation information indication including at least one of a SSB index associated with the DU entity, or a CSI-RS index associated with the DU entity. 
     In some aspects, determining the spatial relation may include receiving a beam configuration indication from a CU or a parent IAB entity. 
     In some aspects, at least one of the SSB index or the CSI-RS index may be associated with different TRPs of the DU entity. 
     In some aspects, the spatial relation information indication further includes at least one of an index of an SSB transmitted by the DU entity within an STC window. 
     In some aspects, configuring the beam may include configuring the downlink transmission of the DU entity with a spatial relation information indication including a sounding reference signal (SRS) index of the MT entity. 
     In some aspects, the spatial relation may correspond to a quasi-co-location of the MT entity and the DU entity. 
     In some aspects, communicating using the beam with at least one entity comprises at least one of the following an uplink transmission by the MT entity, a downlink reception by the MT entity, a downlink transmission by the DU entity, an uplink reception by the DU entity, or measuring one or more signals by one of the MT or DU entities. 
       FIG. 7  is a block diagram of a MIO communication system  700  including a base station  102 , which may be acting as an IAB node or a parent node, and a UE  104 . The MIMO communication system  900  may illustrate aspects of the wireless communication access network  100  described with reference to  FIG. 1 . The base station  102  may be an example of aspects of the base station  102  described with reference to  FIG. 1 . The base station  102  may be equipped with antennas  734  and  735 , and the UE  104  may be equipped with antennas  752  and  753 . In the MIMO communication system  700 , the base station  102  may be able to send data over multiple communication links at the same time. Each communication link may be called a “layer” and the “rank” of the communication link may indicate the number of layers used for communication. For example, in a 2×2 MIMO communication system where base station  102  transmits two “layers,” the rank of the communication link between the base station  102  and the UE  104  is two. 
     At the base station  102 , a transmit (Tx) processor  720  may receive data from a data source. The transmit processor  720  may process the data. The transmit processor  720  may also generate control symbols or reference symbols. A transmit MIMO processor  730  may perform spatial processing (e.g., precoding) on data symbols, control symbols, or reference symbols, if applicable, and may provide output symbol streams to the transmit modulator/demodulators  732  and  733 . Each modulator/demodulator  732  through  733  may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator/demodulator  732  through  733  may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a DL signal. In one example, DL signals from modulator/demodulators  732  and  733  may be transmitted via the antennas  734  and  735 , respectively. 
     The UE  104  may be an example of aspects of the UEs  104  described with reference to  FIGS. 1 and 2 . At the UE  104 , the UE antennas  752  and  753  may receive the DL signals from the base station  102  and may provide the received signals to the modulator/demodulators  754  and  755 , respectively. Each modulator/demodulator  754  through  755  may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each modulator/demodulator  754  through  755  may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector  756  may obtain received symbols from the modulator/demodulators  754  and  755 , perform MIMO detection on the received symbols, if applicable, and provide detected symbols. A receive (Rx) processor  758  may process (e.g., demodulate, deinterleave, and decode) the detected symbols, providing decoded data for the UE  104  to a data output, and provide decoded control information to a processor  980 , or memory  982 . 
     The processor  780  may in some cases execute stored instructions to instantiate a communicating component  242  (see e.g.,  FIGS. 1 and 2 ). 
     On the uplink (UL), at the UE  104 , a transmit processor  764  may receive and process data from a data source. The transmit processor  764  may also generate reference symbols for a reference signal. The symbols from the transmit processor  764  may be precoded by a transmit MIMO processor  766  if applicable, further processed by the modulator/demodulators  754  and  755  (e.g., for SC-FDMA, etc.), and be transmitted to the base station  102  in accordance with the communication parameters received from the base station  102 . At the base station  102 , the UL signals from the UE  104  may be received by the antennas  734  and  735 , processed by the modulator/demodulators  732  and  733 , detected by a MIMO detector  736  if applicable, and further processed by a receive processor  738 . The receive processor  738  may provide decoded data to a data output and to the processor  740  or memory  742 . 
     The components of the UE  104  may, individually or collectively, be implemented with one or more ASICs adapted to perform some or all of the applicable functions in hardware. Each of the noted modules may be a means for performing one or more functions related to operation of the MIMO communication system  900 . Similarly, the components of the base station  102  may, individually or collectively, be implemented with one or more ASICs adapted to perform some or all of the applicable functions in hardware. Each of the noted components may be a means for performing one or more functions related to operation of the MIMO communication system  900 . 
     SOME ADDITIONAL EXAMPLES 
     The aspects described herein additionally include one or more of the following implementation examples described in the following numbered clauses. 
     1. A method of wireless communications at an integrated access and backhaul (IAB) node, comprising: 
     determining a spatial relation between a first communication of a distributed unit (DU) entity and a second communication of one of the DU entity or a co-located mobile termination (MT) entity; 
     configuring a beam of at least one of the MT or the DU based on the determined spatial relation; and 
     communicating using the beam with at least one entity. 
     2. The method of clause  1 , wherein determining the spatial relation includes determining that an uplink transmission of the MT entity is spatially related to a downlink transmission of the DU entity, and 
     wherein configuring the beam includes configuring the uplink transmission of the MT entity with a spatial relation information indication including at least one of:
         a synchronization signal block (SSB) index associated with the DU entity, or   a channel state information reference signal (CSI-RS) index associated with the DU entity.       

     3. The method of any preceding clause, wherein at least one of the SSB index or the CSI-RS index are associated with different transmission reception points (TRPs) of the DU entity. 
     4. The method of any preceding clause, wherein the spatial relation information indication further includes an index of an SSB transmitted by the DU entity within an SSB transmission configuration (STC) window. 
     5. The method of any preceding clause, wherein the index of the SSB corresponds to at least one of a first SSB index with a center frequency or a second SSB index with an STC configuration window. 
     6. The method of any preceding clause, wherein determining the spatial relation includes determining that a downlink reception of the MT entity is spatially related to a downlink transmission of the DU entity, and 
     wherein configuring the beam includes configuring the downlink transmission of the MT entity with a spatial relation information indication including at least one of:
         a synchronization signal block (SSB) index associated with the DU entity, or   a channel state information reference signal (CSI-RS) index associated with the DU entity.       

     7. The method of any preceding clause, wherein at least one of the SSB index or the CSI-RS index are associated with different transmission reception points (TRPs) of the DU entity. 
     8. The method of any preceding clause, wherein the spatial relation information indication further includes an index of an SSB transmitted by the DU entity within an SSB transmission configuration (STC) window. 
     9. The method of any preceding clause, wherein determining the spatial relation includes determining that a first downlink transmission of the DU entity is spatially related to a second downlink transmission of the DU entity, and 
     wherein configuring the beam includes configuring the first downlink transmission of the DU entity with a spatial relation information indication including at least one of:
         a synchronization signal block (SSB) index associated with the DU entity, or   a channel state information reference signal (CSI-RS) index associated with the DU entity.       

     10. The method of any preceding clause, wherein determining the spatial relation includes receiving a beam configuration indication from a central unit (CU) or a parent IAB entity. 
     11. The method of any preceding clause, wherein at least one of the SSB index or the CSI-RS index are associated with different transmission reception points (TRPs) of the DU entity. 
     12. The method of any preceding clause, wherein the spatial relation information indication further includes at least one of: an index of an SSB transmitted by the DU entity within an SSB transmission configuration (STC) window. 
     13. The method of any preceding clause, wherein determining the spatial relation includes determining that a downlink transmission of the DU entity is spatially related to an uplink transmission of the MT entity. 
     14. The method of any preceding clause, wherein configuring the beam includes configuring the downlink transmission of the DU entity with a spatial relation information indication including a sounding reference signal (SRS) index of the MT entity. 
     15. The method of any preceding clause, wherein determining the spatial relation includes determining that an uplink reception of the DU entity is spatially related to a downlink transmission of the DU entity, and 
     wherein configuring the beam includes configuring the uplink reception of the DU entity with a spatial relation information indication including at least one of:
         a synchronization signal block (SSB) index associated with the DU entity, or   a channel state information reference signal (CSI-RS) index associated with the DU entity.       

     16. The method of any preceding clause, wherein determining the spatial relation includes receiving a beam configuration indication from a central unit (CU) or a parent IAB entity. 
     17. The method of any preceding clause, wherein at least one of the SSB index or the CSI-RS index are associated with different transmission reception points (TRPs) of the DU entity. 
     18. The method of any preceding clause, wherein the spatial relation information indication further includes at least one of: an index of an SSB transmitted by the DU entity within an SSB transmission configuration (STC) window. 
     19. The method of any preceding clause, wherein determining the spatial relation includes determining that an uplink reception of the DU entity is spatially related to an uplink transmission of the MT entity. 
     20. The method of any preceding clause, wherein configuring the beam includes configuring the uplink reception of the DU entity with a spatial relation information indication including a sounding reference signal (SRS) index of the MT entity. 
     21. The method of any preceding clause wherein the spatial relation corresponds to a quasi-co-location of the MT entity and the DU entity. 
     22. The method of any preceding clause, wherein communicating using the beam with at least one entity comprises at least one of: 
     an uplink transmission by the MT entity, 
     a downlink reception by the MT entity, 
     a downlink transmission by the DU entity, 
     an uplink reception by the DU entity, or 
     measuring one or more signals by one of the MT or DU entities. 
     23. An apparatus corresponding to an integrated access and backhaul (IAB) node for wireless communication, comprising: 
     a transceiver; 
     a memory configured to store instructions; and 
     at least one processor communicatively coupled with the transceiver and the memory, wherein the at least one processor is configured to:
         determine a spatial relation between a first communication of a distributed unit (DU) entity and a second communication of one of the DU entity or a co-located mobile termination (MT) entity;   configure a beam of at least one of the MT or the DU based on the determined spatial relation; and   communicate using the beam with at least one entity.       

     24. The apparatus of claim  23 , wherein to determine the spatial relation, the at least one processor is further configured to determine that an uplink transmission of the MT entity is spatially related to a downlink transmission of the DU entity, and 
     wherein to configure the beam, the at least one processor is further configured to configure the uplink transmission of the MT entity with a spatial relation information indication including at least one of:
         a synchronization signal block (SSB) index associated with the DU entity, or   a channel state information reference signal (CSI-RS) index associated with the DU entity.       

     25. The apparatus of any preceding clause, wherein to determine the spatial relation, the at least one processor is further configured to determine that a downlink reception of the MT entity is spatially related to a downlink transmission of the DU entity, and 
     wherein to configure the beam, the at least one processor is further configured to configure the downlink transmission of the MT entity with a spatial relation information indication including at least one of:
         a synchronization signal block (SSB) index associated with the DU entity, or   a channel state information reference signal (CSI-RS) index associated with the DU entity.       

     26. The apparatus of any preceding clause, wherein to determine the spatial relation, the at least one processor is further configured to determine that a first downlink transmission of the DU entity is spatially related to a second downlink transmission of the DU entity, and 
     wherein to configure the beam, the at least one processor is further configured to configure the first downlink transmission of the DU entity with a spatial relation information indication including at least one of:
         a synchronization signal block (SSB) index associated with the DU entity, or   a channel state information reference signal (CSI-RS) index associated with the DU entity.       

     27. The apparatus of any preceding clause, wherein to determine the spatial relation, the at least one processor is further configured to determine that a downlink transmission of the DU entity is spatially related to an uplink transmission of the MT entity. 
     28. The apparatus of any preceding clause, wherein to determine the spatial relation, the at least one processor is further configured to determine that an uplink reception of the DU entity is spatially related to a downlink transmission of the DU entity, and 
     wherein to configure the beam, the at least one processor is further configured to configure the uplink reception of the DU entity with a spatial relation information indication including at least one of:
         a synchronization signal block (SSB) index associated with the DU entity, or   a channel state information reference signal (CSI-RS) index associated with the DU entity.       

     29. An apparatus corresponding to an integrated access and backhaul (IAB) node for wireless communication, comprising: 
     means for determining a spatial relation between a first communication of a distributed unit (DU) entity and a second communication of one of the DU entity or a co-located mobile termination (MT) entity; 
     means for configuring a beam of at least one of the MT or the DU based on the determined spatial relation; and 
     means for communicating using the beam with at least one entity. 
     30. A non-transitory computer-readable medium storing computer code executable by a processor for wireless communications at a network entity comprising code for: 
     determining a spatial relation between a first communication of a distributed unit (DU) entity and a second communication of one of the DU entity or a co-located mobile termination (MT) entity; 
     configuring a beam of at least one of the MT or the DU based on the determined spatial relation; and 
     communicating using the beam with at least one entity. 
     The above detailed description set forth above in connection with the appended drawings describes examples and does not represent the only examples that may be implemented or that are within the scope of the claims. The term “example,” when used in this description, means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and apparatuses are shown in block diagram form in order to avoid obscuring the concepts of the described examples. 
     Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, computer-executable code or instructions stored on a computer-readable medium, or any combination thereof. 
     The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a specially-programmed device, such as but not limited to a processor, a digital signal processor (DSP), an ASIC, a FPGA or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination thereof designed to perform the functions described herein. A specially-programmed processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A specially-programmed processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     The functions described herein may be implemented in hardware, software, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a non-transitory computer-readable medium. Other examples and implementations are within the scope and spirit of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a specially programmed processor, hardware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Moreover, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from the context, the phrase, for example, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, for example the phrase “X employs A or B” is satisfied by any of the following instances: X employs A; X employs B; or X employs both A and B. Also, as used herein, including in the claims, “or” as used in a list of items prefaced by “at least one of” indicates a disjunctive list such that, for example, a list of “at least one of A, B, or C” means A or B or C or AB or AC or BC or ABC (A and B and C). 
     Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media. 
     The previous description of the disclosure is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the common principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Furthermore, although elements of the described aspects and/or embodiments may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. Additionally, all or a portion of any aspect and/or embodiment may be utilized with all or a portion of any other aspect and/or embodiment, unless stated otherwise. Thus, the disclosure is not to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.