Patent Publication Number: US-2023156751-A1

Title: Sidelink repeater capability signaling

Description:
TECHNICAL FIELD 
     This application relates to wireless communication systems, and more particularly to sidelink communication systems and networks including wireless repeaters or relay devices. 
     INTRODUCTION 
     Wireless communications 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 capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). A wireless multiple-access communications system may include a number of base stations (BSs), each simultaneously supporting communications for multiple communication devices, which may be otherwise known as user equipment (UE). 
     To meet the growing demands for expanded mobile broadband connectivity, wireless communication technologies are advancing from the long term evolution (LTE) technology to a next generation new radio (NR) technology, which may be referred to as 5 th  Generation (5G). For example, NR is designed to provide a lower latency, a higher bandwidth or a higher throughput, and a higher reliability than LTE. NR is designed to operate over a wide array of spectrum bands, for example, from low-frequency bands below about 1 gigahertz (GHz) and mid-frequency bands from about 1 GHz to about 6 GHz, to high-frequency bands such as millimeter wave (mmWave) bands. NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed and shared spectrum. Spectrum sharing enables operators to opportunistically aggregate spectrums to dynamically support high-bandwidth services. Spectrum sharing can extend the benefit of NR technologies to operating entities that may not have access to a licensed spectrum. 
     In a wireless communication network, a BS may communicate with a UE in an uplink direction and a downlink direction. Sidelink was introduced in LTE to allow a UE to send data to another UE without tunneling through the BS and/or an associated core network. The LTE sidelink technology had been extended to provision for device-to-device (D2D) communications, vehicle-to-everything (V2X) communications, and/or cellular vehicle-to-everything (C-V2X) communications. Similarly, NR may be extended to support sidelink communications, D2D communications, V2X communications, and/or C-V2X over licensed bands and/or unlicensed bands. Sidelink communications may be used in industrial internet-of-things (IIOT) scenarios, for example. 
     BRIEF SUMMARY OF SOME EXAMPLES 
     The following summarizes some aspects of the present disclosure to provide a basic understanding of the discussed technology. This summary is not an extensive overview of all contemplated features of the disclosure and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in summary form as a prelude to the more detailed description that is presented later. 
     According to one aspect of the present disclosure, a method of wireless communication performed by a first wireless communication device includes: initiating a registration protocol for performing repeater operations for sidelink communications; transmitting, to a second wireless communication device, a sidelink capability report indicating sidelink repeating capabilities of the first wireless communication device; receiving a sidelink repeating configuration based on the sidelink capability report; and communicating a first signal based on the sidelink repeating configuration. 
     According to another aspect of the present disclosure, a method of wireless communication performed by a first wireless communication device includes: receiving, from a second wireless communication device, a connection request; receiving, from the second wireless communication device, a sidelink capability report indicating sidelink repeating capabilities of the second wireless communication device; and transmitting, based on the sidelink capability report, a sidelink repeating configuration. 
     According to another aspect of the present disclosure, a first wireless communication device includes: a processor and a transceiver in communication with the processor, wherein the processor and the transceiver are configured to: initiate a registration protocol for performing repeater operations for sidelink communications; transmit, to a second wireless communication device, a sidelink capability report indicating sidelink repeating capabilities of the first wireless communication device; receive a sidelink repeating configuration based on the sidelink capability report; and communicate a first signal based on the sidelink repeating configuration. 
     According to another aspect of the present disclosure, a first wireless communication device includes: a processor and a transceiver in communication with the processor, wherein the processor and the transceiver are configured to: receive, from a second wireless communication device, a connection request; receive, from the second wireless communication device, a sidelink capability report indicating sidelink repeating capabilities of the second wireless communication device; and transmit, based on the sidelink capability report, a sidelink repeating configuration. 
     According to another aspect of the present disclosure, a non-transitory computer-readable medium comprises program code recorded thereon. The program code comprises instructions executable by a processor to cause a first wireless communication device to: initiate a registration protocol for performing repeater operations for sidelink communications; transmit, to a second wireless communication device, a sidelink capability report indicating sidelink repeating capabilities of the first wireless communication device; receive a sidelink repeating configuration based on the sidelink capability report; and communicate a first signal based on the sidelink repeating configuration. 
     According to another aspect of the present disclosure, a non-transitory computer-readable medium comprises program code recorded thereon. The program code comprises instructions executable by a processor to cause a first wireless communication device to: receive, from a second wireless communication device, a connection request; receive, from the second wireless communication device, a sidelink capability report indicating sidelink repeating capabilities of the second wireless communication device; and transmit, based on the sidelink capability report, a sidelink repeating configuration. 
     Other aspects, features, and embodiments of the present invention will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary embodiments of the present invention in conjunction with the accompanying figures. While features of the present invention may be discussed relative to certain embodiments and figures below, all embodiments of the present invention can include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments of the invention discussed herein. In similar fashion, while exemplary embodiments may be discussed below as device, system, or method embodiments it should be understood that such exemplary embodiments can be implemented in various devices, systems, and methods. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates a wireless communication network according to some aspects of the present disclosure. 
         FIG.  2 A  illustrates a wireless communication network that provisions for sidelink communications according to some aspects of the present disclosure. 
         FIG.  2 B  illustrates a wireless communication network that provisions for sidelink communications using a wireless repeater according to some aspects of the present disclosure. 
         FIG.  2 C  illustrates a wireless communication network that provisions for sidelink communications using a wireless repeater according to some aspects of the present disclosure. 
         FIG.  3    is a signaling diagram illustrating a sidelink relay method according to some aspects of the present disclosure. 
         FIG.  4    is a signaling diagram illustrating a sidelink relay method according to some aspects of the present disclosure. 
         FIG.  5    is a block diagram of a wireless repeater device according to some aspects of the present disclosure. 
         FIG.  6    is a block diagram of a user equipment (UE) according to some aspects of the present disclosure. 
         FIG.  7    is a block diagram of an exemplary base station (BS) according to some aspects of the present disclosure. 
         FIG.  8    is a flow diagram of a sidelink communication method according to some aspects of the present disclosure. 
         FIG.  9    is a flow diagram of a sidelink communication method according to some aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below, in connection with the appended drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts. 
     This disclosure relates generally to wireless communications systems, also referred to as wireless communications networks. In various embodiments, the techniques and apparatus may be used for wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks, Global System for Mobile Communications (GSM) networks, 5 th  Generation (5G) or new radio (NR) networks, as well as other communications networks. As described herein, the terms “networks” and “systems” may be used interchangeably. 
     An OFDMA network may implement a radio technology such as evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and the like. UTRA, E-UTRA, and GSM are part of universal mobile telecommunication system (UMTS). In particular, long term evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided from an organization named “3rd Generation Partnership Project” (3GPP), and cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). These various radio technologies and standards are known or are being developed. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications associations that aims to define a globally applicable third generation (3G) mobile phone specification. 3GPP long term evolution (LTE) is a 3GPP project which was aimed at improving the UMTS mobile phone standard. The 3GPP may define specifications for the next generation of mobile networks, mobile systems, and mobile devices. The present disclosure is concerned with the evolution of wireless technologies from LTE, 4G, 5G, NR, and beyond with shared access to wireless spectrum between networks using a collection of new and different radio access technologies or radio air interfaces. 
     In particular, 5G networks contemplate diverse deployments, diverse spectrum, and diverse services and devices that may be implemented using an OFDM-based unified, air interface. In order to achieve these goals, further enhancements to LTE and LTE-A are considered in addition to development of the new radio technology for 5G NR networks. The 5G NR will be capable of scaling to provide coverage (1) to a massive Internet of things (IoTs) with a Ultra-high density (e.g., ˜1M nodes/km 2 ), ultra-low complexity (e.g., ˜10s of bits/sec), ultra-low energy (e.g., ˜10+ years of battery life), and deep coverage with the capability to reach challenging locations; (2) including mission-critical control with strong security to safeguard sensitive personal, financial, or classified information, ultra-high reliability (e.g., ˜99.9999% reliability), ultra-low latency (e.g., ˜1 ms), and users with wide ranges of mobility or lack thereof; and (3) with enhanced mobile broadband including extreme high capacity (e.g., ˜10 Tbps/km 2 ), extreme data rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates), and deep awareness with advanced discovery and optimizations. 
     The 5G NR may be implemented to use optimized OFDM-based waveforms with scalable numerology and transmission time interval (TTI); having a common, flexible framework to efficiently multiplex services and features with a dynamic, low-latency time division duplex (TDD)/frequency division duplex (FDD) design; and with advanced wireless technologies, such as massive multiple input, multiple output (MIMO), robust millimeter wave (mmWave) transmissions, advanced channel coding, and device-centric mobility. Scalability of the numerology in 5G NR, with scaling of subcarrier spacing, may efficiently address operating diverse services across diverse spectrum and diverse deployments. For example, in various outdoor and macro coverage deployments of less than 3 GHz FDD/TDD implementations, subcarrier spacing may occur with 15 kHz, for example over 5, 10, 20 MHz, and the like bandwidth (BW). For other various outdoor and small cell coverage deployments of TDD greater than 3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHz BW. For other various indoor wideband implementations, using a TDD over the unlicensed portion of the 5 GHz band, the subcarrier spacing may occur with 60 kHz over a 160 MHz BW. Finally, for various deployments transmitting with mmWave components at a TDD of 28 GHz, subcarrier spacing may occur with 120 kHz over a 500 MHz BW. 
     The scalable numerology of the 5G NR facilitates scalable TTI for diverse latency and quality of service (QoS) requirements. For example, shorter TTI may be used for low latency and high reliability, while longer TTI may be used for higher spectral efficiency. The efficient multiplexing of long and short TTIs to allow transmissions to start on symbol boundaries. 5G NR also contemplates a self-contained integrated subframe design with UL/downlink scheduling information, data, and acknowledgement in the same subframe. The self-contained integrated subframe supports communications in unlicensed or contention-based shared spectrum, adaptive UL/downlink that may be flexibly configured on a per-cell basis to dynamically switch between UL and downlink to meet the current traffic needs. 
     Various other aspects and features of the disclosure are further described below. It should be apparent that the teachings herein may be embodied in a wide variety of forms and that any specific structure, function, or both being disclosed herein is merely representative and not limiting. Based on the teachings herein one of an ordinary level of skill in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein. For example, a method may be implemented as part of a system, device, apparatus, and/or as instructions stored on a computer readable medium for execution on a processor or computer. Furthermore, an aspect may comprise at least one element of a claim. 
     A 5G NR network may allow for sidelink communication between one or more user equipments (UEs). For example, sidelink communication may be used in a vehicle-to-everything (V2X) communication scenario in which multiple vehicles are communicating information regarding speed, position, route, emergency status, and/or any other suitable information. In another aspect, sidelink communication may be used in an industrial internet of things (HOT) communication scenario in which sidelink communication devices (e.g., UEs) are communicating sensor, status, and/or other data to each other and/or to a controlling node, such as a programmable logic controller (PLC). In some of these use cases, it may be beneficial to support ultra-reliable low latency communications (URLLC) between the sidelink nodes. 
     A sidelink network may operate based on different architectures. For example, a sidelink network may operate in a mode 1 or a mode 2. In mode 1, a BS may control the sidelink communication by, for example, allocating sidelink time and frequency resources to each of the sidelink communication nodes. In some aspects, the BS operating in mode 1 may have more relaxed control of the sidelink communication. For example, the BS may delegate local scheduling for sidelink communications to a sidelink controlling node. In another example, a sidelink network may operate without a BS. Sidelink communication systems that operate without a BS may be referred to as mode 2 sidelink networks. In mode 2 sidelink communication, a controlling sidelink UE or node may schedule sidelink communications to, from, and/or between the other sidelink UEs in the network. 
     In some aspects, a sidelink communication link may be referred to as a “PC5” interface, whereas a communication link between a BS and a UE may be referred to as a “Uu” interface. In some aspects, a wireless communication device may be configured to communicate wirelessly with other wireless communication devices using a Uu interface, a PC5 interface, or both. For example, a wireless communication device may be configured with a first set of time/frequency resources for communicating over the Uu link, and a second set of time/frequency resources for communicating over the PC5 link. 
     A challenge for some sidelink communication scenarios may be obstructions or blockages in the communication path between sidelink nodes. For example, in an IIOT manufacturing scenario, one or more of the sidelink UEs may be mobile, and may be occasionally positioned so as to be physically blocked or obstructed from receiving and/or transmitting communications from or to a controlling sidelink node and/or other sidelink node. These blockages may increase the error rate of communications and/or increase latency, which may degrade URLLC performance. One approach to increasing the reliability of sidelink communications may be using relay devices or repeaters, such as smart repeaters or reflective intelligence surfaces (RIS). These repeaters may offer a relatively inexpensive solution to sub optimal sidelink communications by providing one or more secondary paths between the sidelink nodes. 
     Different types of repeaters or relay devices may have different capabilities or configurations. For example, some repeaters may support only amplify-and-forward (AF) operation with no signal decoding. Other repeaters may be configured to decode received signals (e.g., control information and/or data) before forwarding the received signals to other wireless communication devices. The role the repeater plays in a sidelink communication scenario may depend on its capabilities and configurations. For example, a wireless repeater may be configured with AF-only operation for sidelink communications, but may also be configured to decode and forward Uu signals (e.g., between a BS and a UE). In some aspects, a wireless repeater&#39;s capabilities may be more suitable for a BS-controlled sidelink communication architecture (e.g., mode 1 and/or mode 3). In another example, a wireless repeater&#39;s capabilities may be better exploited in a less BS-dependent sidelink communication architecture (e.g., mode 2 and/or mode 4). If a wireless repeater having a first set of capabilities is deployed in a sidelink communication scenario ill-suited for the wireless repeater, potential benefits and utilities of the repeater may not be fully exploited. Accordingly, sidelink communication performance may be negatively affected. For example, the reliability, latency, and/or throughput of the sidelink communications may not be significantly improved by the wireless repeater. 
     The present application describes mechanisms for indicating the sidelink repeating capabilities of a wireless repeater or relay device to one or more other wireless communication devices in a sidelink communication scenario, and for configuring the wireless repeater for sidelink repeating based on the repeating capabilities. For example, a sidelink communication scheme may include a wireless repeater transmitting, to a wireless communication device (e.g., BS, controlling sidelink UE), a sidelink capability report indicating repeating capabilities of the wireless repeater in a sidelink communication scenario. The communication scheme may further include the wireless communication device transmitting, to the wireless repeater based on the sidelink capability report, a sidelink repeater configuration. The sidelink repeater configuration may indicate one or more operating parameters for the wireless repeater, such as time and/or frequency resources for sidelink and/or Uu repeating, beam direction configurations, and/or transmit power configurations. 
     The sidelink capability report may be transmitted by the wireless repeater to a base station (BS), to a sidelink controlling node, and/or to one or more sidelink UEs. The operations of the wireless repeater may be controlled by the BS and/or the sidelink controlling node. The sidelink capability report may indicate, for example, the wireless repeater&#39;s decoding capabilities, beam capabilities, frequency granularity, carrier aggregation and switching capabilities, channel sensing capabilities, and/or any other suitable sidelink or repeater capability. 
     Aspects of the present disclosure may provide several benefits. For example, the repeater capability signaling schemes and mechanisms described in the present disclosure advantageously allow a wireless repeater to be configured and used in a sidelink communication scenario consistent with its capabilities. Thus, the repeater may be used in a mode of operation that more effectively uses the repeater in the sidelink communication scheme. Accordingly, the reliability, latency, throughput of the sidelink communications, power savings, and/or user experience can be more greatly improved by the repeater. 
       FIG.  1    illustrates a wireless communication network  100  according to some aspects of the present disclosure. The network  100  may be a 5G network. The network  100  includes a number of base stations (BSs)  105  (individually labeled as  105   a ,  105   b ,  105   c ,  105   d , and  105   e ) and other network entities. A BS  105  may be a station that communicates with UEs  115  and may also be referred to as an evolved node B (eNB), a next generation eNB (gNB), an access point, and the like. Each BS  105  may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to this particular geographic coverage area of a BS  105  and/or a BS subsystem serving the coverage area, depending on the context in which the term is used. A repeater  110  is also present in the network  100 . The repeater  110  may be configured to relay communications between wireless communication devices in the network  100 . For example, the repeater  110  may extend the coverage area of the network to areas that would otherwise be unavailable for communications. In dense settings with physical obstructions, the repeater  110  may improve reliability and network performance. 
     A BS  105  may provide communication coverage for a macro cell or a small cell, such as a pico cell or a femto cell, and/or other types of cell. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a pico cell, would generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a femto cell, would also generally cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). A BS for a macro cell may be referred to as a macro BS. A BS for a small cell may be referred to as a small cell BS, a pico BS, a femto BS or a home BS. In the example shown in  FIG.  1   , the BSs  105   d  and  105   e  may be regular macro BSs, while the BSs  105   a - 105   c  may be macro BSs enabled with one of three dimension (3D), full dimension (FD), or massive MIMO. The BSs  105   a - 105   c  may take advantage of their higher dimension MIMO capabilities to exploit 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. A BS  105  may support one or multiple (e.g., two, three, four, and the like) cells. 
     The network  100  may support synchronous or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time. 
     The UEs  115  are dispersed throughout the wireless network  100 , and each UE  115  may be stationary or mobile. A UE  115  may also be referred to as a terminal, a mobile station, a subscriber unit, a station, or the like. A UE  115  may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or the like. In one aspect, a UE  115  may be a device that includes a Universal Integrated Circuit Card (UICC). In another aspect, a UE may be a device that does not include a UICC. In some aspects, the UEs  115  that do not include UICCs may also be referred to as IoT devices or internet of everything (IoE) devices. The UEs  115   a - 115   d  are examples of mobile smart phone-type devices accessing network  100 . A UE  115  may also be a machine specifically configured for connected communication, including machine type communication (MTC), enhanced MTC (eMTC), narrowband IoT (NB-IoT) and the like. The UEs  115   e - 115   h  are examples of various machines configured for communication that access the network  100 . The UEs  115   i - 115   k  are examples of vehicles equipped with wireless communication devices configured for communication that access the network  100 . A UE  115  may be able to communicate with any type of the BSs, whether macro BS, small cell, or the like. In  FIG.  1   , a lightning bolt (e.g., communication links) indicates wireless transmissions between a UE  115  and a serving BS  105 , which is a BS designated to serve the UE  115  on the downlink (DL) and/or uplink (UL), desired transmission between BSs  105 , backhaul transmissions between BSs, or sidelink transmissions between UEs  115 . 
     In operation, the BSs  105   a - 105   c  may serve the UEs  115   a  and  115   b  using 3D beamforming and coordinated spatial techniques, such as coordinated multipoint (CoMP) or multi-connectivity. The macro BS  105   d  may perform backhaul communications with the BSs  105   a - 105   c , as well as small cell, and the repeater  110 . The macro BS  105   d  may also transmits multicast services which are subscribed to and received by the UEs  115   c  and  115   d . Such multicast services may include mobile television or stream video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or gray alerts. 
     The BSs  105  may also communicate with a core network. The core network may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of the BSs  105  (e.g., which may be an example of a gNB or an access node controller (ANC)) may interface with the core network through backhaul links (e.g., NG-C, NG-U, etc.) and may perform radio configuration and scheduling for communication with the UEs  115 . In various examples, the BSs  105  may communicate, either directly or indirectly (e.g., through core network), with each other over backhaul links (e.g., X1, X2, etc.), which may be wired or wireless communication links. 
     The network  100  may also support mission critical communications with ultra-reliable and redundant links for mission critical devices, such as the UE  115   e , which may be a drone. Redundant communication links with the UE  115   e  may include links from the macro BSs  105   d  and  105   e . Other machine type devices, such as the UE  115   f  (e.g., a thermometer), the UE  115   g  (e.g., smart meter), and UE  115   h  (e.g., wearable device) may communicate through the network  100  either directly with BSs, such as the macro BS  105   e , or in multi-step-size configurations by communicating with another user device (e.g., repeater  110 ), which relays its information to the network, such as the UE  115   f  communicating temperature measurement information to the smart meter, the UE  115   g , which is then reported to the network through the repeater  110  and the BS  105   d . The network  100  may also provide additional network efficiency through dynamic, low-latency TDD/FDD communications, such as V2V, V2X, C-V2X communications between a UE  115   i ,  115   j , or  115   k  and other UEs  115 , and/or vehicle-to-infrastructure (V2I) communications between a UE  115   i ,  115   j , or  115   k  and a BS  105 . In some aspects, the repeater  110  may be configured to amplify-and-forward sidelink communications from one UE  115  to another UE  115 , and/or between a UE  115  and a BS  105 . 
     In some implementations, the network  100  utilizes OFDM-based waveforms for communications. An OFDM-based system may partition the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, bins, or the like. Each subcarrier may be modulated with data. In some instances, the subcarrier spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system BW. The system BW may also be partitioned into subbands. In other instances, the subcarrier spacing and/or the duration of TTIs may be scalable. 
     In some aspects, the BSs  105  can assign or schedule transmission resources (e.g., in the form of time-frequency resource blocks (RB)) for downlink (DL) and uplink (UL) transmissions in the network  100 . DL refers to the transmission direction from a BS  105  to a UE  115 , whereas UL refers to the transmission direction from a UE  115  to a BS  105 . The communication can be in the form of radio frames. A radio frame may be divided into a plurality of subframes or slots, for example, about 10. Each slot may be further divided into mini-slots. In a FDD mode, simultaneous UL and DL transmissions may occur in different frequency bands. For example, each subframe includes a UL subframe in a UL frequency band and a DL subframe in a DL frequency band. In a TDD mode, UL and DL transmissions occur at different time periods using the same frequency band. For example, a subset of the subframes (e.g., DL subframes) in a radio frame may be used for DL transmissions and another subset of the subframes (e.g., UL subframes) in the radio frame may be used for UL transmissions. 
     The DL subframes and the UL subframes can be further divided into several regions. For example, each DL or UL subframe may have pre-defined regions for transmissions of reference signals, control information, and data. Reference signals are predetermined signals that facilitate the communications between the BSs  105  and the UEs  115 . For example, a reference signal can have a particular pilot pattern or structure, where pilot tones may span across an operational BW or frequency band, each positioned at a pre-defined time and a pre-defined frequency. For example, a BS  105  may transmit cell specific reference signals (CRSs) and/or channel state information—reference signals (CSI-RSs) to enable a UE  115  to estimate a DL channel. Similarly, a UE  115  may transmit sounding reference signals (SRSs) to enable a BS  105  to estimate a UL channel Control information may include resource assignments and protocol controls. Data may include protocol data and/or operational data. In some aspects, the BSs  105  and the UEs  115  may communicate using self-contained subframes. A self-contained subframe may include a portion for DL communication and a portion for UL communication. A self-contained subframe can be DL-centric or UL-centric. A DL-centric subframe may include a longer duration for DL communication than for UL communication. A UL-centric subframe may include a longer duration for UL communication than for UL communication. 
     In some aspects, the network  100  may be an NR network deployed over a licensed spectrum. The BSs  105  can transmit synchronization signals (e.g., including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS)) in the network  100  to facilitate synchronization. The BSs  105  can broadcast system information associated with the network  100  (e.g., including a master information block (MIB), remaining system information (RMSI), and other system information (OSI)) to facilitate initial network access. In some instances, the BSs  105  may broadcast the PSS, the SSS, and/or the MIB in the form of synchronization signal block (SSBs) over a physical broadcast channel (PBCH) and may broadcast the RMSI and/or the OSI over a physical downlink shared channel (PDSCH). 
     In some aspects, a UE  115  attempting to access the network  100  may perform an initial cell search by detecting a PSS from a BS  105 . The PSS may enable synchronization of period timing and may indicate a physical layer identity value. The UE  115  may then receive a SSS. The SSS may enable radio frame synchronization, and may provide a cell identity value, which may be combined with the physical layer identity value to identify the cell. The PSS and the SSS may be located in a central portion of a carrier or any suitable frequencies within the carrier. 
     After receiving the PSS and SSS, the UE  115  may receive a MIB. The MIB may include system information for initial network access and scheduling information for RMSI and/or OSI. After decoding the MIB, the UE  115  may receive RMSI and/or OSI. The RMSI and/or OSI may include radio resource control (RRC) information related to random access channel (RACH) procedures, paging, control resource set (CORESET) for physical downlink control channel (PDCCH) monitoring, physical UL control channel (PUCCH), physical UL shared channel (PUSCH), power control, and SRS. 
     After obtaining the MIB, the RMSI and/or the OSI, the UE  115  can perform a random access procedure to establish a connection with the BS  105 . In some examples, the random access procedure may be a four-step random access procedure. For example, the UE  115  may transmit a random access preamble and the BS  105  may respond with a random access response. The random access response (RAR) may include a detected random access preamble identifier (ID) corresponding to the random access preamble, timing advance (TA) information, a UL grant, a temporary cell-radio network temporary identifier (C-RNTI), and/or a backoff indicator. Upon receiving the random access response, the UE  115  may transmit a connection request to the BS  105  and the BS  105  may respond with a connection response. The connection response may indicate a contention resolution. In some examples, the random access preamble, the RAR, the connection request, and the connection response can be referred to as message 1 (MSG1), message 2 (MSG2), message 3 (MSG3), and message 4 (MSG4), respectively. In some examples, the random access procedure may be a two-step random access procedure, where the UE  115  may transmit a random access preamble and a connection request in a single transmission and the BS  105  may respond by transmitting a random access response and a connection response in a single transmission. 
     After establishing a connection, the UE  115  and the BS  105  can enter a normal operation stage, where operational data may be exchanged. For example, the BS  105  may schedule the UE  115  for UL and/or DL communications. The BS  105  may transmit UL and/or DL scheduling grants to the UE  115  via a PDCCH. The scheduling grants may be transmitted in the form of DL control information (DCI). The BS  105  may transmit a DL communication signal (e.g., carrying data) to the UE  115  via a PDSCH according to a DL scheduling grant. The UE  115  may transmit a UL communication signal to the BS  105  via a PUSCH and/or PUCCH according to a UL scheduling grant. 
     In some aspects, the BS  105  may communicate with a UE  115  using HARQ techniques to improve communication reliability, for example, to provide a URLLC service. The BS  105  may schedule a UE  115  for a PDSCH communication by transmitting a DL grant in a PDCCH. The BS  105  may transmit a DL data packet to the UE  115  according to the schedule in the PDSCH. The DL data packet may be transmitted in the form of a transport block (TB). If the UE  115  receives the DL data packet successfully, the UE  115  may transmit a HARQ ACK to the BS  105 . Conversely, if the UE  115  fails to receive the DL transmission successfully, the UE  115  may transmit a HARQ NACK to the BS  105 . Upon receiving a HARQ NACK from the UE  115 , the BS  105  may retransmit the DL data packet to the UE  115 . The retransmission may include the same coded version of DL data as the initial transmission. Alternatively, the retransmission may include a different coded version of the DL data than the initial transmission. The UE  115  may apply soft-combining to combine the encoded data received from the initial transmission and the retransmission for decoding. The BS  105  and the UE  115  may also apply HARQ for UL communications using substantially similar mechanisms as the DL HARQ. 
     In some aspects, the network  100  may operate over a system BW or a component carrier (CC) BW. The network  100  may partition the system BW into multiple BWPs (e.g., portions). A BS  105  may dynamically assign a UE  115  to operate over a certain BWP (e.g., a certain portion of the system BW). The assigned BWP may be referred to as the active BWP. The UE  115  may monitor the active BWP for signaling information from the BS  105 . The BS  105  may schedule the UE  115  for UL or DL communications in the active BWP. In some aspects, a BS  105  may assign a pair of BWPs within the CC to a UE  115  for UL and DL communications. For example, the BWP pair may include one BWP for UL communications and one BWP for DL communications. 
     In some aspects, the network  100  may operate over a shared channel, which may include shared frequency bands or unlicensed frequency bands. For example, the network  100  may be an NR-unlicensed (NR-U) network operating over an unlicensed frequency band. In such an aspect, the BSs  105  and the UEs  115  may be operated by multiple network operating entities. To avoid collisions, the BSs  105  and the UEs  115  may employ a listen-before-talk (LBT) procedure to monitor for transmission opportunities (TXOPs) in the shared channel. For example, a transmitting node (e.g., a BS  105  or a UE  115 ) may perform an LBT prior to transmitting in the channel. When the LBT passes, the transmitting node may proceed with the transmission. When the LBT fails, the transmitting node may refrain from transmitting in the channel. In an example, the LBT may be based on energy detection. For example, the LBT results in a pass when signal energy measured from the channel is below a threshold. Conversely, the LBT results in a failure when signal energy measured from the channel exceeds the threshold. In another example, the LBT may be based on signal detection. For example, the LBT results in a pass when a channel reservation signal (e.g., a predetermined preamble signal) is not detected in the channel A TXOP may also be referred to as channel occupancy time (COT). 
     In some aspects, the network  100  may provision for sidelink communications to allow a UE  115  to communicate with another UE  115  without tunneling through a BS  105  and/or the core network. The BS  105  may configure certain resources in a licensed band and/or an unlicensed band for sidelink communications between the UE  115  and the other UE  115 . For example, as described above, to improve coverage and/or otherwise improve performance for URLLC applications, the network  100  may include the relay device or repeater  110 . For example, the repeater  110  may include a smart repeater or reflective intelligent surface (RIS) to provide for additional communication paths and/or wider coverage area for UEs  115  communicating via sidelink. The repeater  110  may be used in different modes to provide different sidelink services. The present disclosure describes mechanisms for signaling a repeater&#39;s sidelink repeating capabilities, and for configuring the repeater based on the capability signaling. 
       FIG.  2 A  illustrates an example of a wireless communication network  200   a  that provisions for sidelink communications according to embodiments of the present disclosure. The network  200   a  may be similar to the network  100 .  FIG.  2 A  illustrates one BS  205  and four UEs  215  for purposes of simplicity of discussion, though it will be recognized that embodiments of the present disclosure may scale to any suitable number of UEs  215  and/or BSs  205  (e.g., the about 2, 3, 6, 7, 8, or more). The BS  205  and the UEs  215  may be similar to the BSs  105  and the UEs  115 , respectively. The BSs  205  and the UEs  215  may communicate over the same spectrum. 
     In the network  200   a , some of the UEs  215  may communicate with each other in peer-to-peer communications. For example, the UE  215   a  may communicate with the UE  215   b  over a sidelink  251 , and the UE  215   c  may communicate with the UE  215   d  over another sidelink  252 . In some instances, the sidelinks  251  and  252  are unicast bidirectional links, each between a pair of UEs  215 . In some other instances, the sidelinks  251  and  252  can be multicast links supporting multicast sidelink services among the UEs  215 . For instance, the UE  215   c  may transmit multicast data to the UE  215   d  and the UE  215   b  over sidelinks. Some of the UEs  215  may also communicate with the BS  205  in a UL direction and/or a DL direction via communication links  253 . For instance, the UE  215   a ,  215   b , and  215   c  are within a coverage area  210  of the BS  205 , and thus may be in communication with the BS  205 . The UE  215   d  is outside the coverage area  210 , and thus may not be in direct communication with the BS  205 . In some instances, the UE  215   c  may operate as a relay for the UE  215   d  to reach the BS  205 . In some aspects, some of the UEs  215  are associated with vehicles (e.g., similar to the UEs  115   i - k ) and the communications over the sidelinks  251  and/or  252  may be C-V2X communications or IIOT communications. 
     In some aspects, the network  200   a  may be a LTE network or a 5G NR. The transmissions by the UE  215   a  and the UE  215   b  over the sidelink  251  and/or the transmissions by the UE  215   c  and the UE  215   d  over the sidelink  252  may use a LTE PUSCH waveform, which is a discrete Fourier transform-spreading (DFT-s) based waveform. In some aspects, the network  200   a  may be an NR network. The transmissions by the UEs  215  over the sidelinks  251  and/or  252  may use a cyclic-prefix-OFDM (CP-OFDM) waveform. 
       FIGS.  2 B and  2 C  illustrate wireless communication networks  200   b ,  200   c  that provision for sidelink communication in which a sidelink controlling node  207  and a repeater  209  are deployed. For the purposes of the present disclosure, the repeater  209  may be referred to as an assisting node (AN) or a relay device. The repeater  209  may include a reflective intelligent surface (RIS), smart repeater, or any other suitable type of relay device. The controlling node  207  may include a sidelink UE, for example. In some aspects, the controlling node  207  may have more sidelink capabilities than the UEs  215 . For example, the controlling node  207  may be configured for local scheduling of sidelink resources for communications with the sidelink UEs  215 . In other aspects, the controlling node  207  may have more advanced beam capabilities than the UEs  215 , greater coverage area, and/or greater bandwidth compared to the UEs  215 . Each of  FIGS.  2 B and  2 C  illustrates a different control node and repeater deployment scheme for the sidelink communications. In this regard,  FIG.  2 B  illustrates a first mode or sidelink architecture in which the repeater  209  is configured and controlled by the BS  205 . The repeater  209  may be configured to amplify and forward communications between the BS  205  and the controlling node  207 , and/or between the BS  205  and one or more of the UEs  215 . In another example, the repeater  209  may be configured to amplify and forward communications between the controlling node  207  and one or more UEs  215 . In another example, the repeater  209  may be configured to amplify and forward communications between two or more sidelink UEs  215 . In another example, the repeater  209  may be configured to decode and forward communications between the BS  205  and the controlling node  207 , and/or between the BS  205  and the one or more of the UEs  215 . In another example, the repeater  209  may be configured to decode and forward communications between the controlling node  207  and one or more UEs  215 . In another example, the repeater  209  may be configured to decode and forward communications between two or more sidelink UEs  215 . Further, it will be understood that the repeater  209  may be configured to perform repeating operations in a combination of the scenarios presented above. For example, the repeater  209  may be configured to amplify and forward, and/or decode and forward, communications between the BS  205  and the controlling node  207 , between the controlling node  207  and one or more UEs  215 , between the BS  205  and one or more UEs  215 , and/or between individual UEs  215 . 
     In some aspects, the repeater  209  may be configured to decode one or more of a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), a physical sidelink feedback channel (PSFCH), a physical broadcast channel (PBCH), and/or a physical sidelink discovery channel (PSDCH). The decoding capability may allow for an improved signal-to-noise ratio (SNR) in the communications between the BS  205 , the controlling node  207 , and/or the sidelink UEs  215 . In some aspects, the scheme shown in  FIG.  2 B  may be referred to as mode 1 sidelink communication. 
     In mode 1 sidelink communication, the BS  205  communicates with the controlling node  207  via a first link  250 . The first link  250  may be a Uu interface. In another example, the first link  250  may be a sidelink interface. The BS  205  also communicates directly to at least one of the UEs  215   a  via a communication link  253 . In some aspects, the BS  205  may communicate control information (e.g., DCI, RRC configurations) to the controlling node  207  via the first link  250 . In some aspects, the BS  205  may receive control information and/or sidelink data from the controlling node  207  via the first link  250 . In some aspects, the BS  205  may allocate sidelink resources or resource pools directly to the UEs  215  via communication links  253 . Further, the BS  205  may communicate control information to and/or from the UEs  215  via the communication link  253 . The UEs  215  may communicate sidelink data to the controlling node  207  via sidelinks  251 . For example, the network  200   b  may be deployed in an industrial Internet of things (HOT) scenario in a factory or other industrial environment. The UEs  215  may be in communication with sensors, machinery, and/or other industrial components. The UEs  215  may be configured to communicate the data to the controlling node  207 . The controlling node  207  may be in communication with a processing system or controller for the industrial equipment. For example, the controlling node  207  may be in communication with a programmable logic controller (PLC) configured to receive the sensor data and control machinery based on the sensor data. 
     The repeater  209  is deployed in the network  200   b  and is configured to communicate with the BS  205  via a second link  254 . The repeater  209  is also configured to communicate with at least the controlling node  207  via a third link  255 . In some aspects, the second link  254  may be a Uu link, or a sidelink. In some aspects, the third link  255  may be a Uu link or a sidelink. In some aspects, the second link  254  and the third link  255  may provide alternative links or communication paths between the BS  205  and the controlling node  207 . In other aspects, the first link  254  and the third link  255  may be a primary communication path between the BS  205  and the controlling node  207 . For example, the BS  205  may perform the same functions described above with respect to the first link  250  using the second link  254  and the third link  255 . 
     In some aspects, the repeater  209  may be further configured to communicate directly to one or more of the UEs  215 . For example, the repeater  209  may provide a communication path between the controlling node  207  and the one or more UEs  215 . The repeater  209  may receive control information and/or commands via a Uu link  254  for sidelink repeating operations between the repeater  209  and the controlling node  207 . The repeater  209 , based on the control information, may also repeat sidelink communications between the sidelink UE  215   b  and the controlling node  207  using links  255  and  257 . In another example, the repeater  209  may provide a communication path between the BS  205  and the one or more UEs  215 . 
       FIG.  2 C  illustrates a network  200   c  in which the controlling node  207  and the repeater  209  are deployed according to a different architecture or mode. For example, the scenario illustrated in  FIG.  2 C  may be a mode 2 sidelink operation in which the controlling node  207  may autonomously or semi-autonomously schedule sidelink communications and allocate sidelink resources. In this regard, the BS  205  may communicate with the controlling node  207  via the first communication link  250 , but may not communicate directly with the UEs  215 . In the example shown in  FIG.  2 C , the controlling node  207  communicates with the UEs  215  via sidelinks  251 . Although the BS  205  is shown in the network  200   c , in some aspects, the BS  205  may not be present in the network  200   c . For example, the controlling node  207  may operate autonomously without communicating with the BS  205 . 
     In some aspects, the controlling node  207  may also control or configure the repeater  209 . For example, the controlling node  207  may allocate sidelink resources or resource pools, schedule on/off times for the repeater  209 , transmit beam configurations, power configurations, and/or any other suitable communication configuration. In some instances, an obstacle  50  may be present that blocks sidelink communications between the controlling node  207  and at least one of the UEs (e.g.,  215   b ). Accordingly, the controlling node  207  may communicate with the blocked UE  215   b  via the repeater  209 . In particular, the controlling node  207  may transmit and receive sidelink communications from the UE  215   b  via a second link  254  and a third link  255 , as shown. 
     Referring generally to  FIGS.  2 B and  2 C , the operation of the repeater  209  may be based on the repeater&#39;s capabilities. For example, in some aspects, the repeater  209  may be more suitable for one sidelink communication mode (e.g., mode A), and less suitable for a different sidelink communication mode (e.g., mode B, mode 2). In some instances, a repeater  209  may have more capabilities (e.g., decoding and forwarding, beamforming), such that the use of the repeater  209  may be more advantageous in certain configurations. The present disclosure describes schemes and mechanisms for signaling sidelink repeater capabilities, and for configuring a repeater for sidelink communications based on the signaled sidelink repeater capability. 
       FIG.  3    is a signaling diagram of a method  300  for reporting sidelink repeater capabilities, according to an aspect of the present disclosure. The method  300  may be performed by a BS  105 , a repeater  110 , and a sidelink UE  115 . The BS  105  may be one of the BSs  105  in the network  100 , and/or one of the BSs  205  in one of the networks  200   a - 200   c . The sidelink UE  115  may be one of the UEs  115  in the network  100 , one of the UEs  215  in the networks  200   a - 200   c , or the controlling node  207  in the networks  200   b ,  200   c . The repeater  110  may be one of the UEs  115  in the network  100 , or one of the repeaters  209  in the networks  200   b ,  200   c . According to the method  300 , the repeater  110  may signal its repeating and/or sidelink communication capabilities to the network via the BS  105 , and may receive a sidelink repeating configuration based on the signaled capabilities. 
     At action  302 , the repeater  110  transmits, and the BS  105  receives, a registration request. In some aspects, the registration request indicates a request for the repeater  110  to perform repeater operations in a sidelink network. In some aspects, action  302  may be part of a cell search and/or initial access procedure. In some aspects, action  302  may include performing a random access procedure and establishing a radio resource control (RRC) connection status. For example, in some aspects, the BS  105  may transmit system information to the second wireless communication device (e.g., MIB, SIB1), receive a RACH preamble, transmit a RACH response, receive a RRC Setup Request message, transmit a RRC Setup message, receive a RRC Setup Complete message, and receiving a non-access stratum (NAS) Registration indication. Action  302  may further include additional NAS registration, UE capability signaling, and/or registration completion acknowledgement procedures. 
     In some aspects, action  302  may further include the repeater  110  transmitting, and the BS  105  receiving, one or more repeater configurations and/or capabilities. For example, the BS  105  may receive, from the repeater  110 , a signal indicating that the repeater  110  supports repeating for sidelink (PC5) and/or Uu communication links. In other aspects, action  302  may be omitted from the method  300 . For example, the repeater  110  may be configured to perform repeating operations in the network without being registered to the network. 
     At action  304 , the BS  105  transmits, to the repeater  110 , a signal authorizing the second wireless communication device to perform sidelink repeating operations during the registration protocol. Accordingly, while the BS  105  communicates with higher layers of the protocol stack (e.g., NAS), the repeater  110  may be configured to perform at least some repeating operations in the sidelink network. In some aspects, action  304  includes the BS  105  transmitting an RRC message indicating a connection confirmation. In some aspects the RRC communication may be transmitted in a PDSCH, PSSCH, and/or any other suitable channel. In other aspects, the authorization signal may include transmitting a MAC-CE and/or MAC-PDU. In other aspects, transmitting the authorization signal may include transmitting the signal in a PSCCH, PDCCH, and/or any other suitable communication channel. 
     At action  306 , the BS  105  transmits, and the repeater  110  receives, a registration confirmation message. In some aspects, the registration confirmation message may include a RRC message indicating that the repeater  110  has successfully registered on the network. In some aspects, the message may include or indicate authorization for communicating in the network from one or more higher layers in the network (e.g., distributed unit (DU), centralized unit (CU), core network (CN). In some aspects, actions  304  and  306  may be accomplished in a same step. For example, action  304  and  306  may include transmitting a registration confirmation message that authorizes the second wireless communication device to perform sidelink repeating operations. 
     At action  308 , the repeater  110  transmits, to the BS  105 , a sidelink capability report. The sidelink capability report may indicate sidelink repeating capabilities of the repeater  110 . In some aspects, action  308  includes transmitting, to the BS  105 , a RRC message, a MAC-CE, MAC-PDU, UCI, SCI, and/or any other suitable type of communication. For example, action  308  may include the repeater  110  transmitting a RepeaterCapabilitySidelink RRC message. In some aspects, the repeater  110  transmits the sidelink capability report in response to being registered to the network associated with the BS  105 . 
     The sidelink capability report may include or indicate one or more capabilities of the repeater  110  associated with repeating operations and/or sidelink communications. For example, the sidelink capability report may include or indicate a sidelink synchronization signal block (S-SSB) capability. The S-SSB capability may include or indicate the repeater&#39;s  110  ability to transmit and/or receive a S-SSB. In some aspects, the S-SSB capability may include or indicate the repeater&#39;s  110  ability to decode and/or amplify and forward a S-SSB. For example, the sidelink capability report may indicate that the repeater  110  is configured to receive, but not transmit, a S-SSB. In another example, the sidelink capability report may indicate that the repeater  110  is configured to receive, decode, and transmit a S-SSB. In other examples, the sidelink capability report may indicate that the repeater  110  is configured only to amplify-and-forward (AF) an S-SSB. Other SSB Tx/Rx capabilities may also be included in the sidelink capability report. For example, the sidelink capability report may indicate a supported tx/rx periodicity of the S-SSB. For example, the sidelink capability report may indicate that the repeater  110  is configured to transmit and/or receive up to 20 S-SSB within 160 ms, up to 40 S-SSB within 160 ms, up to 60 S-SSB within 160 ms, and/or any other suitable S-SSB periodicity configuration. 
     In another aspect, the sidelink capability report may include or indicate the repeater&#39;s  110  ability for physical sidelink control channel (PSCCH) decoding. For example, the sidelink capability report may indicate whether the repeater  110  is configured to decode a PSCCH, or is only configured for AF of the PSCCH. In another aspect, the sidelink capability report may indicate how many PSCCH decodings and/or transmissions the repeater  110  can perform within a time period (e.g., frame, slot, sub-slot, etc.). In another aspect, the sidelink capability report may include or indicate the repeater&#39;s  110  capability for physical sidelink shared channel (PSSCH) decoding. For example, the sidelink capability report may indicate whether the repeater  110  is configured to decode a PSSCH, or is only configured for AF of the PSSCH. In another aspect, the sidelink capability report may indicate how many PSSCH decodings and/or transmissions the repeater  110  can perform within a time period (e.g., frame, slot, sub-slot, etc.). In another aspect, the sidelink capability report may indicate a number of SCI-2 the repeater  110  can transmit and/or receive in a time period (e.g., frame, slot, sub-slot, etc.). In another aspect, the sidelink capability report may indicate whether the repeater  110  is configured to decode SCI. In another aspect, the sidelink capability report may include or indicate the repeater&#39;s  110  ability for physical sidelink feedback channel (PSFCH) decoding. For example, the sidelink capability report may indicate whether the repeater  110  is configured to decode a PSFCH, or is only configured for AF of the PSFCH. In another aspect, the sidelink capability report may indicate the number of PSFCH the repeater  110  can simultaneously receive and/or decode. In some aspects, the sidelink capability report may indicate that the repeater  110  is configured to simultaneously transmit M PSFCH communications. In another aspect, the sidelink capability report may indicate that the repeater  110  is configured to simultaneously receive N PSFCH communications. 
     In another aspect, the sidelink capability report may include or indicate beam capabilities of the repeater  110 . For example, the sidelink capability report may indicate a number of radiofrequency Tx/Rx panels or antennas that can be used for sidelink communications. In another aspect, the sidelink capability report may indicate a number of simultaneous transmit/receive beams that can be used for sidelink communications and/or Uu communications with a BS and/or UE. In another aspect, the sidelink capability report may indicate a power class associated with the repeater  110 . For example, the sidelink communication report may indicate a transmit power class of the repeater  110 . In another aspect, the sidelink capability report may indicate a frequency granularity of the repeater  110 . In some aspects, the frequency granularity may include a subcarrier spacing (SCS), supported bandwidth, and/or tunable frequency granularity and its associated delay. In one example, the indicated frequency granularity may include a maximum supported bandwidth and/or one bandwidth of a few pre-configured bandwidths, such as 5 MHz, 20 MHz, 40 MHz, 100 MHz, and/or any other suitable bandwidth. In another example, the frequency granularity indicated in the sidelink capability report may indicate that the repeater  110  may support bandwidths that are integer multiples of a bandwidth B up to a maximum of Bmax. In some aspects, B can be indicated in kHz or MHz. In some aspects, the sidelink capability report may indicate a frequency-selective amplify-and-forward granularity. In another aspect, the sidelink capability report may indicate AF decoding/processing capabilities for each carrier and/or for each bandwidth part (BWP). In another aspect, the sidelink capability report may indicate AF decoding/processing capabilities for one or more carriers, including a combination or set of carriers. In another aspect, the sidelink capability report may indicate a carrier capability of the repeater  110 . For example, the sidelink capability report may indicate whether the repeater  110  is configured for simultaneous operation on Uu and PC5 communication links. Further, the sidelink capability report may indicate whether the repeater  110  is configured to switch between carriers. The sidelink capability report may indicate a switching delay associated with the repeater  110  switching between the carriers. In some aspects, the sidelink capability report may indicate a sensing or measuring capability of the repeater  110 . For example, the sidelink capability report may indicate whether the repeater  110  is configured for spectrum sensing or energy detection for autonomous PC5 operation. In another aspect, the sidelink capability report may indicate whether the repeater  110  is configured to measure reference signal reserve power (RSRP), received signal strength indicator (RSSI), and/or channel busy ratio (CBR) of sidelink signals and channels. In another aspect, the sidelink capability report may indicate the repeater&#39;s  110  capability for SL-CSI-RS transmission and/or reception. 
     In some aspects, the sidelink capability report may indicate a class or category of repeater. Each class or category of repeater may be associated with one or more of the capabilities described above. For example, the sidelink capability report may indicate a first repeater class associated with a first S-SSB capability, a first decoding (e.g., PSCCH, PSSCH, and/or PSFCH) capability, a first beam capability, a first power class, a first frequency capability, a first frequency granularity, and/or a first sensing measurement capability. In some aspects, the first repeater class may indicate, for example, that AF operation is used for all sidelink channels. In another example, the repeater class may indicate that the repeater  110  is configured to simultaneously receive and decode M PSFCH, and simultaneously transmit N PSFCH. For example, the BS  105  receiving the sidelink capability report may be configured with a table indicating the sidelink capabilities associated with a signaled repeater class. Accordingly, the BS  105  may be configured to identify or determine the capabilities of the repeater  110  based on the indicated repeater class. 
     At action  310 , the BS  105  determines, based on the sidelink capability report, a sidelink repeater configuration for the repeater  110 . In some aspects, the sidelink repeating configuration may indicate parameters or configurations for PC5 repeating operation, Uu repeating operation, or both PC5 and Uu repeating operation. In some aspects, the sidelink repeating configuration may indicate on and/or off time periods for repeating operations. For example, the sidelink repeating configuration may indicate semi-static time resources (e.g., frames, slots, sub-slots, symbols, etc.) at which the repeater  110  will be “on” and performing sidelink repeating operations. In another aspect, the sidelink repeating configuration may indicate frequency carriers, BWPs, and/or other frequency resources for sidelink communication, Uu communication, and/or both sidelink communication and Uu communication. In some aspects, the sidelink repeating configuration may indicate one or more beam directions for receiving Uu communications (e.g., from the BS). In another aspect, the sidelink repeating configuration may indicate one or more beam directions for receiving sidelink signals. In another aspect, the sidelink repeating configuration may indicate one or more beam directions for transmitting Uu and/or sidelink communications. In another aspect, the sidelink repeating configuration may indicate a transmit power configuration for the repeater  110 . For example, the sidelink repeating configuration may indicate a maximum power and/or a power split for each of a plurality of carriers (e.g., a maximum power for each of the plurality of carriers and/or an aggregate maximum power across the plurality of carriers). The transmit power may be specific to sidelink communications or Uu communications, or may be common for Uu and sidelink communications. 
     At action  312 , the BS  105  transmits, and the repeater  110  receives, the sidelink repeater configuration. In some aspects, transmitting the sidelink repeater configuration comprises transmitting a RRC message indicating the configuration. In other aspects, transmitting the sidelink repeater configuration comprises transmitting a media access control-control element (MAC-CE) and/or a MAC protocol data unit (PDU) indicating the configuration. In some aspects, the BS  105  may transmit the sidelink repeater configuration in a shared channel. For example, the BS  105  may transmit the configuration in a PDSCH, a PSSCH, and/or any other suitable channel. 
     At action  314 , the BS  105  transmits a communication. The communication may include control information, data, reference signals, and/or any other suitable type of communication. In some aspects, action  314  includes transmitting in a control channel, shared channel or data channel, sidelink channel, broadcast channel, feedback channel, and/or any other suitable type of channel. For example, action  314  may include transmitting the communication in a PDSCH, PDCCH, PSSCH, PSCCH, PSFCH, PBCH, and/or any other channel. 
     At action  316 , the repeater  110  forwards the communication to a sidelink UE  115 . In some aspects, action  316  includes performing an amplify-and-forward (AF) operation. In some aspects, the repeater  110  decodes and forwards the communication to the sidelink UE  115 . In the illustrated example, the communication originates at the BS  105 . For example, the repeater  110  may receive the communication from the BS  105 , and forward the communication to the sidelink UE  115 . In other aspects, the communication originates at a different wireless communication device. For example, the communication may originate at a different sidelink UE. In some aspects, the sidelink UE  115  may include a controlling sidelink UE or node. In this regard, the communication may include or indicate control information intended for the sidelink UE  115 . In some aspects, the control information may indicate sidelink resources and/or configurations for performing sidelink communications in the sidelink network. In other aspects, the communication may originate at a different sidelink UE in the sidelink network. For example, the repeater  110  may receive sidelink data from a different sidelink UE, and forward the sidelink communication to the sidelink UE  115 . 
       FIG.  4    is a signaling diagram of a method  400  for reporting sidelink repeater capabilities, according to an aspect of the present disclosure. The method  400  may be performed by a BS  105 , a repeater  110 , and a sidelink UE  115 . The BS  105  may be one of the BSs  105  in the network  100 , on one of the BSs  205  in one of the networks  200   a - 200   c . The sidelink UE  115  may be on one of the UEs  115  in the network  100 , one of the UEs  215  in the networks  200   a - 200   c , or the controlling node  207  in the networks  200   b ,  200   c . The repeater  110  may be one of the UEs  115  in the network  100 , or one of the repeaters  209  in the networks  200   b ,  200   c . According to the method  400 , the repeater  110  may signal its repeating and/or sidelink communication capabilities to the sidelink UE  115 , and may receive a sidelink repeating configuration based on the signaled capabilities from the sidelink UE  115 . In an exemplary aspect, the sidelink UE  115  may be a controlling sidelink UE or controlling node. For example, the sidelink UE  115  may be coupled with a programmable logic controller (PLC). 
     At action  402 , the repeater is registered to the network via the BS  105 . In some aspects, action  402  may include performing a random access procedure and establishing a radio resource control (RRC) connection status. For example, in some aspects, the BS  105  may transmit system information to the second wireless communication device (e.g., MIB, SIB1), receive a RACH preamble, transmit a RACH response, receive a RRC Setup Request message, transmit a RRC Setup message, receive a RRC Setup Complete message, and receiving NAS Registration indication. Action  402  may further include additional NAS registration, UE capability signaling, and/or registration completion acknowledgement procedures. In some aspects, action  402  may be omitted from the method  400 . For example, the repeater  110  may be configured to perform repeating operations without first being registered to the network. 
     At action  404 , the repeater  110  and the sidelink UE  115  perform a sidelink discovery procedure. For example, the repeater  110  may signal its presence to a sidelink UE  115 , and the sidelink UE  115  may signal its presence to the repeater  110 . The sidelink discovery procedure may further include transmitting and/or receiving sidelink control information (SCI) to or from the sidelink UE  115 . The sidelink discovery procedure may include communicating in a physical sidelink discovery channel (PSDCH), for example. In some aspects, the sidelink discovery procedure may further include transmitting or signaling an identity of the repeater  110 , and/or receiving a signal indicating an identity of another sidelink UE. In some aspects, action  404  may be omitted from the method  400 . For example, the repeater  110  may be configured to perform repeating operations without first performing the sidelink discovery procedure. 
     In some aspects, action  404  may further include the repeater  110  transmitting, to a sidelink UE  115 , one or more repeater configurations and/or capabilities. For example, the repeater  110  may transmit, to a base station, a signal indicating that the repeater  110  supports repeating for sidelink (PC5) and/or Uu communication links. In some aspects, action  404  may further include the repeater  110  receiving a signal authorizing the repeater  110  to perform sidelink repeating operations during the registration protocol. In some aspects, the repeater  110  is configured to share the sidelink configurations or capabilities described above in response to receiving a request from a network, for example via a BS. 
     In some aspects, action  404  may further include the repeater  110  transmitting, and the sidelink UE  115  receiving, one or more repeater configurations and/or capabilities. For example, the sidelink UE  115  may receive, from the repeater  110 , a signal indicating that the repeater  110  supports repeating for sidelink (PC5) and/or Uu communication links. 
     At action  406 , the repeater  110  transmits, to the sidelink UE  115 , a sidelink capability report. The sidelink capability report may indicate sidelink repeating capabilities of the repeater  110 . In some aspects, action  408  includes transmitting, to the sidelink UE  115 , a RRC message. For example, action  408  may include the repeater  110  transmitting a PC5RepeaterCapabilitySidelink RRC message. In some aspects, the repeater  110  transmits the sidelink capability report in response to being authorized by the higher layers of the network&#39;s protocol stack. For example, the sidelink UE  115  and the BS  105  may communicate signals to authorize the repeater  110  for communicating in the network. 
     The sidelink capability report may include or indicate one or more capabilities of the repeater  110  associated with repeating operations and/or sidelink communications. For example, the sidelink capability report may include or indicate a sidelink synchronization signal block (S-SSB) capability. The S-SSB capability may include or indicate the repeater&#39;s  110  ability to transmit and/or receive a S-SSB. In some aspects, the S-SSB capability may include or indicate the repeater&#39;s  110  ability to decode and/or amplify and forward a S-SSB. For example, the sidelink capability report may indicate that the repeater  110  is configured to receive, but not transmit, a S-SSB. In another example, the sidelink capability report may indicate that the repeater  110  is configured to receive, decode, and transmit a S-SSB. In other examples, the sidelink capability report may indicate that the repeater  110  is configured only to amplify-and-forward (AF) an S-SSB. Other SSB Tx/Rx capabilities may also be included in the sidelink capability report. 
     In another aspect, the sidelink capability report may include or indicate the repeater&#39;s  110  ability for physical sidelink control channel (PSCCH) decoding. For example, the sidelink capability report may indicate whether the repeater  110  is configured to decode a PSCCH, or is only configured for AF of the PSCCH. In another aspect, the sidelink capability report may indicate how many PSCCH decodings and/or transmissions the repeater  110  can perform within a slot. In another aspect, the sidelink capability report may include or indicate the repeater&#39;s  110  capability for decoding a sidelink data channel, such as physical sidelink shared channel (PSSCH) decoding. For example, the sidelink capability report may indicate whether the repeater  110  is configured to decode a PSSCH, or is only configured for AF of the PSSCH. In another aspect, the sidelink capability report may indicate how many PSSCH decodings and/or transmissions the repeater  110  can perform within a slot. In another aspect, the sidelink capability report may indicate a number of SCI-2 the repeater  110  can transmit and/or receive in a slot. In another aspect, the sidelink capability report may indicate whether the repeater  110  is configured to decode SCI. In another aspect, the sidelink capability report may include or indicate the repeater&#39;s  110  ability for physical sidelink feedback channel (PSFCH) decoding. For example, the sidelink capability report may indicate whether the repeater  110  is configured to decode a PSFCH, or is only configured for AF of the PSFCH. In another aspect, the sidelink capability report may indicate the number of PSFCH the repeater  110  can simultaneously receive and/or decode. In some aspects, the sidelink capability report may indicate that the repeater  110  is configured to simultaneously transmit M PSFCH communications. In another aspect, the sidelink capability report may indicate that the repeater  110  is configured to simultaneously receive N PSFCH communications. 
     In another aspect, the sidelink capability report may include or indicate beam capabilities of the repeater  110 . For example, the sidelink capability report may indicate a number of radiofrequency Tx/Rx panels or antennas that can be used for sidelink transmission. In another aspect, the sidelink capability report may indicate a number of simultaneous transmit/receive beams that can be used for sidelink communication and/or Uu communication with a BS and/or UE. In another aspect, the sidelink capability report may indicate a power class associated with the repeater  110 . For example, the sidelink communication report may indicate a transmit power class of the repeater  110 . In another aspect, the sidelink capability report may indicate a frequency granularity of the repeater  110 . For example, the sidelink capability report may indicate a frequency-selective amplify-and-forward granularity. In another aspect, the sidelink capability report may indicate AF operation for each carrier and/or for each bandwidth part (BWP). In another aspect, the sidelink capability report may indicate AF decoding/processing capabilities for one or more carriers, including a combination or set of carriers. In another aspect, the sidelink capability report may indicate a carrier capability of the repeater  110 . For example, the sidelink capability report may indicate whether the repeater  110  is configured for simultaneous operation on Uu and PC5 communication links. Further, the sidelink capability report may indicate whether the repeater  110  is configured to switch between carriers. The sidelink capability report may indicate a switching delay associated with switching between the carriers. In some aspects, the sidelink capability report may indicate a sensing or measuring capability of the repeater  110 . For example, the sidelink capability report may indicate whether the repeater  110  is configured for spectrum sensing or energy detection for autonomous PC5 operation. In another aspect, the sidelink capability report may indicate whether the repeater  110  is configured to measure reference signal reserve power (RSRP), received signal strength indicator (RSSI), and/or channel busy ratio (CBR) of sidelink signals and channels. In another aspect, the sidelink capability report may indicate the repeater&#39;s  110  capability for SL-CSI-RS transmission and/or reception. 
     In some aspects, the sidelink capability report may indicate a class or category of repeater. Each class or category of repeater may be associated with one or more of the capabilities described above. For example, the sidelink capability report may indicate a first repeater class associated with a first S-SSB capability, a first decoding (e.g., PSCCH, PSSCH, and/or PSFCH) capability, a first beam capability, a first power class, a first frequency capability, a first frequency granularity, and/or a first sensing measurement capability. In some aspects, the first repeater class may indicate, for example, that AF operation is used for all sidelink channels. In another example, the repeater class may indicate that the repeater  110  is configured to simultaneously receive and decode M PSFCH, and simultaneously transmit N PSFCH. For example, the sidelink UE  115  receiving the sidelink capability report may be configured with a table indicating the sidelink capabilities associated with a signaled repeater class. Accordingly, the sidelink UE  115  may be configured to identify or determine the capabilities of the repeater  110  based on the indicated repeater class. 
     In some aspects, the sidelink capability report may include or indicate a subset of the capabilities described above with respect to  FIG.  3   . For example, the sidelink capability report may include or indicate capabilities related to sidelink communication (PC5), but may include fewer capabilities, or no capabilities, for Uu communications. In some aspects, the capability report may be based on a Uu connection status with the BS  105  and the network. For example, if the repeater  110  is connected and registered with the network, the capability report may include or indicate the repeater&#39;s  110  Uu repeating capabilities and/or Uu communication capabilities with the network. For example, if the repeater  110  is still connected to the network, the capability report may indicate a capability for relaying data traffic to the BS  105  and the network. If the repeater  110  is in idle mode, or no longer connected to the network, the capability report may indicate only sidelink repeating capabilities, and may not indicate Uu communication capabilities. 
     In some aspects, the transmission of the sidelink capability report in action  406  may be triggered by, or based on, receiving authentication or verification from the network and/or from the sidelink UE  115 . For example, the transmission of the sidelink capability report may be based on receiving authentication from the higher layers of the protocol stack (e.g., DU, CU, CN) of the network, or the higher layers (e.g., NAS) of the sidelink UE  115 . 
     At action  408 , the sidelink UE  115  determines, based on the sidelink capability report, a sidelink repeater configuration for the repeater  110 . In some aspects, the sidelink repeating configuration may indicate parameters or configurations for PC5 repeating operation. In some aspects, the sidelink repeating configuration may indicate on and/or off time periods for repeating operations. For example, the sidelink repeating configuration may indicate semi-static time resources (e.g., frames, slots, sub-slots, symbols, etc.) at which the repeater  110  will be “on” and performing sidelink repeating operations. In another aspect, the sidelink repeating configuration may indicate frequency carriers, BWPs, and/or other frequency resources for sidelink communication, Uu communication, and/or both sidelink communication and Uu communication. In some aspects, the sidelink repeating configuration may one or more beam directions for receiving sidelink signals from the sidelink UE  115  and/or from other sidelink UEs. In another aspect, the sidelink repeating configuration may indicate one or more beam directions for transmitting Uu and/or sidelink communications. In another aspect, the sidelink repeating configuration may indicate a transmit power configuration for the repeater  110 . For example, the sidelink repeating configuration may indicate a maximum power and/or a power split for each of a plurality of carriers (e.g., a maximum power for each of the plurality of carriers and/or an aggregate maximum power across the plurality of carriers). The transmit power may be specific to sidelink communications or Uu communications, or may be common for Uu and sidelink communications. 
     At action  410 , the sidelink UE  115  transmits, and the repeater  110  receives, the sidelink repeater configuration. In some aspects, transmitting the sidelink repeater configuration comprises transmitting a RRC message indicating the configuration. In other aspects, transmitting the sidelink repeater configuration comprises transmitting a media access control-control element (MAC-CE) and/or a MAC protocol data unit (PDU) indicating the configuration. In some aspects, the sidelink UE  115  may transmit the sidelink repeater configuration in a shared channel. For example, the sidelink UE  115  may transmit the configuration in a PSSCH, PSCCH, and/or any other suitable channel. 
     At action  412 , the repeater  110  forwards a communication to the sidelink UE  115 . In some aspects, action  412  includes performing an amplify-and-forward (AF) operation. In some aspects, the repeater  110  decodes and forwards the communication to the sidelink UE  115 . In some aspects, the communication  414  may include or indicate sidelink data and/or control information intended for the sidelink UE  115 . In some aspects, the repeater  110  may receive sidelink data from a different sidelink UE, and forward the sidelink communication to the sidelink UE  115 . 
       FIG.  5    is a block diagram of an exemplary UE  500  according to some aspects of the present disclosure. The UE  500  may be a UE  115  discussed above in  FIG.  1   . In some aspects, the UE  500  is configured for sidelink communication, such as one of the UEs  215  discussed above in  FIGS.  2 A- 2 C . In another aspect, the UE  500  may be a controlling sidelink node, such as the node  207  discussed above in  FIGS.  2 B   2 C, and/or the sidelink UE  115  described with respect to  FIG.  4   . As shown, the UE  500  may include a processor  502 , a memory  504 , an sidelink communication module  508 , a transceiver  510  including a modem subsystem  512  and a radio frequency (RF) unit  514 , and one or more antennas  516 . These elements may be in direct or indirect communication with each other, for example via one or more buses. 
     The processor  502  may include a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor  502  may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     The memory  504  may include a cache memory (e.g., a cache memory of the processor  502 ), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, solid state memory device, hard disk drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In an aspect, the memory  504  includes a non-transitory computer-readable medium. The memory  504  may store, or have recorded thereon, instructions  506 . The instructions  506  may include instructions that, when executed by the processor  502 , cause the processor  502  to perform the operations described herein with reference to the UEs  115  in connection with aspects of the present disclosure, for example, aspects of  FIGS.  6 - 13   . Instructions  506  may also be referred to as program code. The program code may be for causing a wireless communication device to perform these operations, for example by causing one or more processors (such as processor  502 ) to control or command the wireless communication device to do so. The terms “instructions” and “code” should be interpreted broadly to include any type of computer-readable statement(s). For example, the terms “instructions” and “code” may refer to one or more programs, routines, sub-routines, functions, procedures, etc. “Instructions” and “code” may include a single computer-readable statement or many computer-readable statements. 
     The sidelink communication module  508  may be implemented via hardware, software, or combinations thereof. For example, the sidelink communication module  508  may be implemented as a processor, circuit, and/or instructions  506  stored in the memory  504  and executed by the processor  502 . In some instances, the sidelink communication module  508  can be integrated within the modem subsystem  512 . For example, the sidelink communication module  508  can be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem  512 . 
     The sidelink communication module  508  may be used for various aspects of the present disclosure, for example, aspects of  FIGS.  2 A- 4   . The sidelink communication module  508  is configured to transmit a sidelink repeating configuration to a repeater, relay device, or assisting node (AN) based on a signaled sidelink capability report from the repeater. For example, in some aspects, the sidelink communication module  508  is configured to receive, from the repeater, a connection request. The connection request may be received as part of a sidelink discovery procedure, in some aspects. The sidelink communication module  508  may be further configured to receive, from the repeater, a sidelink capability report indicating sidelink repeating capabilities of the repeater. For example, the sidelink capability report may indicate the ability of the repeater to receive, forward, and/or decode communications between sidelink UEs, (PC5 communication link) and/or between a UE and the network (Uu communication link). The sidelink capability report may further indicate one or more beam capabilities or configurations for the repeater. In some aspects, the report indicates how many channels (e.g., PSFCH, PSCCH) the repeater can simultaneously decode, receive, and/or transmit. 
     In another aspect, the sidelink communication module  508  is configured to transmit a sidelink repeating configuration to the repeater. The sidelink repeating configuration may be based on the sidelink capability report from the repeater. In this regard, the sidelink repeating configuration may facilitate operation of the repeater in a way that takes advantage of the repeater&#39;s capabilities in the sidelink network. 
     As shown, the transceiver  510  may include the modem subsystem  512  and the RF unit  514 . The transceiver  510  can be configured to communicate bi-directionally with other devices, such as the BSs  105 . The modem subsystem  512  may be configured to modulate and/or encode the data from the memory  504  and/or the sidelink communication module  508  according to a modulation and coding scheme (MCS), e.g., a low-density parity check (LDPC) coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit  514  may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data (e.g., PSSCH data and/or PSCCH control information, COT sharing SCI, HARQ ACK/NACK) from the modem subsystem  512  (on outbound transmissions) or of transmissions originating from another source such as a UE  115  or a BS  105 . The RF unit  514  may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver  510 , the modem subsystem  512  and the RF unit  514  may be separate devices that are coupled together at the UE  115  to enable the UE  115  to communicate with other devices. 
     The RF unit  514  may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas  516  for transmission to one or more other devices. The antennas  516  may further receive data messages transmitted from other devices. The antennas  516  may provide the received data messages for processing and/or demodulation at the transceiver  510 . The transceiver  510  may provide the demodulated and decoded data (e.g., PSSCH data and/or PSCCH control information, PSFCH feedback information, SCI, HARQ ACK/NACK) to the sidelink communication module  508  for processing. The antennas  516  may include multiple antennas of similar or different designs in order to sustain multiple transmission links. The RF unit  514  may configure the antennas  516 . 
     In an example, the transceiver  510  is configured to transmit PSSCH data, PSCCH SCI, sidelink COT sharing SCI, sidelink scheduling SCI, and/or physical sidelink feedback channel (PSFCH) ACK/NACK feedbacks to another UE and/or receive PSSCH data, PSCCH SCI, sidelink COT sharing SCI, sidelink scheduling SCI, and/or PSFCH ACK/NACK feedbacks from another UE, for example, by coordinating with the sidelink communication module  508 . 
     In an aspect, the UE  500  can include multiple transceivers  510  implementing different RATs (e.g., NR and LTE). In an aspect, the UE  500  can include a single transceiver  510  implementing multiple RATs (e.g., NR and LTE). In an aspect, the transceiver  510  can include various components, where different combinations of components can implement different RATs. 
       FIG.  6    is a block diagram of an exemplary BS  600  according to some aspects of the present disclosure. The BS  600  may be a BS  105  in the network  100  as discussed above in  FIG.  1   . As shown, the BS  600  may include a processor  602 , a memory  604 , an sidelink configuration module  608 , a transceiver  610  including a modem subsystem  612  and a RF unit  614 , and one or more antennas  616 . These elements may be in direct or indirect communication with each other, for example via one or more buses. 
     The processor  602  may have various features as a specific-type processor. For example, these may include a CPU, a DSP, an ASIC, a controller, a FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor  602  may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     The memory  604  may include a cache memory (e.g., a cache memory of the processor  602 ), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, a solid state memory device, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some aspects, the memory  604  may include a non-transitory computer-readable medium. The memory  604  may store instructions  606 . The instructions  606  may include instructions that, when executed by the processor  602 , cause the processor  602  to perform operations described herein, for example, aspects of  FIGS.  6 - 10   . Instructions  606  may also be referred to as code, which may be interpreted broadly to include any type of computer-readable statement(s) as discussed above with respect to  FIG.  4   . 
     The sidelink configuration module  608  may be implemented via hardware, software, or combinations thereof. For example, the sidelink configuration module  608  may be implemented as a processor, circuit, and/or instructions  606  stored in the memory  604  and executed by the processor  602 . In some instances, the sidelink configuration module  608  can be integrated within the modem subsystem  612 . For example, the sidelink configuration module  608  can be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem  612 . 
     The sidelink configuration module  608  may be used for various aspects of the present disclosure, for example, aspects of  FIGS.  2 A- 4   . The sidelink configuration module  608  is configured to transmit a sidelink repeating configuration to a repeater, relay device, or assisting node (AN) based on a signaled sidelink capability report from the repeater. For example, in some aspects, the sidelink configuration module  608  is configured to receive, from the repeater, a connection request. The connection request may be received as part of a sidelink discovery procedure, in some aspects. The sidelink configuration module  608  may be further configured to receive, from the repeater, a sidelink capability report indicating sidelink repeating capabilities of the repeater. For example, the sidelink capability report may indicate the ability of the repeater to receive, forward, and/or decode communications between sidelink UEs, (PC5 communication link) and/or between a UE and the network (Uu communication link). The sidelink capability report may further indicate one or more beam capabilities or configurations for the repeater. In some aspects, the report indicates how many channels (e.g., PSFCH, PSCCH) the repeater can simultaneously decode, receive, and/or transmit. 
     In another aspect, the sidelink configuration module  608  is configured to transmit a sidelink repeating configuration to the repeater. The sidelink repeating configuration may be based on the sidelink capability report from the repeater. In this regard, the sidelink repeating configuration may facilitate operation of the repeater in a way that takes advantage of the repeater&#39;s capabilities in the sidelink network. 
     As shown, the transceiver  610  may include the modem subsystem  612  and the RF unit  614 . The transceiver  610  can be configured to communicate bi-directionally with other devices, such as the UEs  115  and/or  500  and/or another core network element. The modem subsystem  612  may be configured to modulate and/or encode data according to a MCS, e.g., a LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit  614  may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data (e.g., a sidelink resource configuration, sidelink COT sharing configuration) from the modem subsystem  612  (on outbound transmissions) or of transmissions originating from another source such as a UE  115  and/or UE  500 . The RF unit  614  may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver  610 , the modem subsystem  612  and/or the RF unit  614  may be separate devices that are coupled together at the BS  105  to enable the BS  105  to communicate with other devices. 
     The RF unit  614  may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas  616  for transmission to one or more other devices. This may include, for example, transmission of information to complete attachment to a network and communication with a camped UE  115  or  500  according to some aspects of the present disclosure. The antennas  616  may further receive data messages transmitted from other devices and provide the received data messages for processing and/or demodulation at the transceiver  610 . The transceiver  610  may provide the demodulated and decoded data (e.g., a sidelink resource configuration request, a sidelink COT sharing request) to the sidelink configuration module  608  for processing. The antennas  616  may include multiple antennas of similar or different designs in order to sustain multiple transmission links. 
     In an example, the transceiver  610  is configured to transmit a resource configuration to a UE (e.g., the UEs  115  and  400 ) indicating a frequency interlace and receive a UL control channel signal (e.g., a PUCCH signal) modulated by HARQ ACK/NACK and SR from the UE in the frequency interlace, for example, by coordinating with the sidelink configuration module  608 . 
     In an aspect, the BS  600  can include multiple transceivers  610  implementing different RATs (e.g., NR and LTE). In an aspect, the BS  600  can include a single transceiver  610  implementing multiple RATs (e.g., NR and LTE). In an aspect, the transceiver  610  can include various components, where different combinations of components can implement different RATs. 
       FIG.  7    is a block diagram of an exemplary repeater  700  according to some aspects of the present disclosure. The repeater  700  may be a repeater  110  in the network  100  as discussed above in  FIG.  1   . A shown, the repeater  700  may include a processor  702 , a memory  704 , an sidelink communication module  708 , a transceiver  710  including a modem subsystem  712  and a RF unit  714 , and one or more antennas  716 . These elements may be in direct or indirect communication with each other, for example via one or more buses. 
     The processor  702  may have various features as a specific-type processor. For example, these may include a CPU, a DSP, an ASIC, a controller, a FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor  702  may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     The memory  704  may include a cache memory (e.g., a cache memory of the processor  702 ), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, a solid state memory device, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some aspects, the memory  704  may include a non-transitory computer-readable medium. The memory  704  may store instructions  706 . The instructions  706  may include instructions that, when executed by the processor  702 , cause the processor  702  to perform operations described herein, for example, aspects of  FIGS.  7 - 10   . Instructions  706  may also be referred to as code, which may be interpreted broadly to include any type of computer-readable statement(s) as discussed above with respect to  FIG.  4   . 
     The sidelink communication module  708  may be implemented via hardware, software, or combinations thereof. For example, the sidelink communication module  708  may be implemented as a processor, circuit, and/or instructions  706  stored in the memory  704  and executed by the processor  702 . In some instances, the sidelink communication module  708  can be integrated within the modem subsystem  712 . For example, the sidelink communication module  708  can be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem  712 . 
     The sidelink communication module  708  may be used for various aspects of the present disclosure, for example, aspects of  FIGS.  2 A- 4   . The sidelink communication module  708  is configured to signal a sidelink repeating capability to a second wireless communication device, such as the BS  600  and/or the UE  500 , and to receive a sidelink repeating capability based on the report. For example, the sidelink communication module  708  may be configured to initiate a registration protocol for performing repeater operations in a sidelink network. In some aspects, initiating the registration protocol includes performing a RACH protocol to connect to the network. In other aspects, initiating the registration protocol includes performing a sidelink discovery procedure. The sidelink communication module  708  may also be configured to transmit, to the second wireless communication device, a sidelink capability report indicating sidelink repeating capabilities of the first wireless communication device. For example, the sidelink capability report may indicate the ability of the repeater  700  to receive, forward, and/or decode communications between sidelink UEs, (PC5 communication link) and/or between a UE and the network (Uu communication link). The sidelink capability report may further indicate one or more beam capabilities or configurations for the repeater  700 . In some aspects, the report indicates how many channels (e.g., PSFCH, PSCCH) the repeater  700  can simultaneously decode, receive, and/or transmit. 
     In another aspect, the sidelink communication module  708  is configured to receive a sidelink repeating configuration from the second wireless communication device. The sidelink repeating configuration may be based on the sidelink capability report. In this regard, the sidelink repeating configuration may facilitate operation of the repeater  700  in a way that takes advantage of the repeater&#39;s capabilities in the sidelink network. In another aspect, the sidelink communication module  708  is configured to communicate a first signal based on the sidelink repeating configuration. In some aspects, the sidelink communication module  708  is configured to receive and/or transmit the first signal from or to another wireless communication device, such as the second wireless communication device. For example, the sidelink communication module  708  may be configured to receive, from a third wireless communication device, a first sidelink signal, and forward the first sidelink signal to the second wireless communication device. In another example, the sidelink communication module  708  may be configured to receive, from the second wireless communication device, a first signal, and forward the received first signal to a BS. In some aspects, the sidelink communication module  708  may be configured to amplify-and-forward the first signal with no signal decoding. In other aspects, the sidelink communication module  708  may be configured to receive and decode the first signal, and transmit the decoded first signal to another wireless communication device. In some aspects, the first signal may include control information (e.g., SCI-1, SCI-2). In other aspects, the first signal may include sidelink data. For example, the first signal may be carried in a PSSCH. 
     As shown, the transceiver  710  may include the modem subsystem  712  and the RF unit  714 . The transceiver  710  can be configured to communicate bi-directionally with other devices, such as the UEs  115  and/or  400  and/or another core network element. The modem subsystem  712  may be configured to modulate and/or encode data according to a MCS, e.g., a LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit  714  may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data (e.g., a sidelink resource configuration, sidelink COT sharing configuration) from the modem subsystem  712  (on outbound transmissions) or of transmissions originating from another source such as a UE  115  and/or UE  400 . The RF unit  714  may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver  710 , the modem subsystem  712  and/or the RF unit  714  may be separate devices that are coupled together at the repeater  105  to enable the repeater  105  to communicate with other devices. 
     The RF unit  714  may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas  716  for transmission to one or more other devices. This may include, for example, transmission of information to complete attachment to a network and communication with a camped UE  115  or  400  according to some aspects of the present disclosure. The antennas  716  may further receive data messages transmitted from other devices and provide the received data messages for processing and/or demodulation at the transceiver  710 . The transceiver  710  may provide the demodulated and decoded data (e.g., a sidelink resource configuration request, a sidelink COT sharing request) to the sidelink communication module  708  for processing. The antennas  716  may include multiple antennas of similar or different designs in order to sustain multiple transmission links. 
     In an aspect, the repeater  700  can include multiple transceivers  710  implementing different RATs (e.g., NR and LTE). In an aspect, the repeater  700  can include a single transceiver  710  implementing multiple RATs (e.g., NR and LTE). In an aspect, the transceiver  710  can include various components, where different combinations of components can implement different RATs. 
       FIG.  8    is a flow diagram of a sidelink communication method  800  according to some aspects of the present disclosure. Steps of the method  800  can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the steps. For example, a wireless communication device, such as a relay device or repeater, may be configured to perform the steps of the method  800 . In some aspects, the repeater may include one of the repeaters  209  in the networks  200   b ,  200   c , or the repeater  700 . Other aspects of the method  800  may be performed by a UE, such as one of the UEs  115 ,  215 ,  500 , described above. In one example, the repeater  700 , may utilize one or more components, such as the processor  502 , the memory  504 , the sidelink communication module  508 , the transceiver  510 , the modem  512 , and the one or more antennas  516 , to execute the steps of method  800 . The method  800  may employ similar mechanisms as in the methods  300 ,  400  described above with respect to  FIGS.  3  and  4   , respectively. As illustrated, the method  800  includes a number of enumerated steps, but aspects of the method  800  may include additional steps before, after, and in between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order. 
     At step  810 , the method  800  includes a first wireless communication device initiating a registration protocol for performing repeater operations in a sidelink network. In some aspects, initiating the registration protocol may include performing a cell search and/or initial access procedure for example. In some aspects, initiating the registration protocol may include performing a random access procedure and establishing a radio resource control (RRC) connection status with a base station (BS) or other wireless communication device. For example, step  810  may include receiving system information from the BS (e.g., MIB, SIB1), transmitting a RACH preamble, receiving a RACH response, transmitting a RRC Setup Request message, receiving a RRC Setup message, transmitting a RRC Setup Complete message, and requesting NAS Registration. In some aspects step  810  may include transmitting the message in a PUCCH, PUSCH, PSSCH, PSCCH, and/or any other suitable channel Step  810  may further include additional NAS registration, UE capability signaling, and/or registration completion acknowledgement procedures. 
     In other aspects, initiating the registration protocol for performing repeater operations may include performing a sidelink discovery procedure. For example, the first wireless communication device may signal its presence to a second wireless communication device, and the second wireless communication device may signal its presence to the first wireless communication device. The sidelink discovery procedure may further include transmitting and/or receiving sidelink control information (SCI) to or from the second wireless communication device. The sidelink discovery procedure may include communicating in a physical sidelink discovery channel (PSDCH), for example. In other aspects, the discovery procedure may include communicating in a sidelink shared channel (PSSCH), a sidelink control channel (PSCCH), and/or any other suitable channel. In some aspects, the sidelink discovery procedure may further include transmitting or signaling an identity of the first wireless communication device, and/or receiving a signal indicating an identity of another sidelink UE. 
     In some aspects, step  810  may further include the first wireless communication device transmitting, to a second wireless communication device, one or more repeater configurations and/or capabilities. For example, the first wireless communication device may transmit, to a base station, a signal indicating that the first wireless communication device supports repeating for sidelink (PC5) and/or Uu communication links. In some aspects, the method  800  may further include the first wireless communication device receiving a signal authorizing the first wireless communication device to perform sidelink repeating operations during the registration protocol. In some aspects, the first wireless communication device is configured to share the sidelink configurations or capabilities described above in response to receiving a request from a network, for example via a BS. 
     The registration protocol may include messages communicated between the second wireless communication device and various protocol stacks of the network and their associated components and equipment, including distributed units (DU), central units (CU), and/or the core network (CN). 
     At step  820 , the first wireless communication device transmits, to a second wireless communication device, a sidelink capability report. The sidelink capability report may indicate sidelink repeating capabilities of the first wireless communication device. In some aspects, step  820  includes transmitting, to the second wireless communication device, a RRC message. For example, step  820  may include the first wireless communication device transmitting a RepeaterCapabilitySidelink RRC message. In another example, if the second wireless communication device is a sidelink communication device (e.g., sidelink UE), step  820  may include transmitting a PC5RepeaterCapabilitySidelink message. In some aspects, the first wireless communication device transmits the sidelink capability report in response to being registered to the second wireless communication device, or to a network associated with the second wireless communication device. 
     The sidelink capability report may include or indicate one or more capabilities of the first wireless communication device associated with repeating operations and/or sidelink communications. For example, the sidelink capability report may include or indicate a sidelink synchronization signal block (S-SSB) capability. The S-SSB capability may include or indicate the first wireless communication device&#39;s capability to transmit and/or receive a S-SSB. In some aspects, the S-SSB capability may include or indicate the first wireless communication device&#39;s capability to decode and/or amplify and forward a S-SSB. For example, the sidelink capability report may indicate that the first wireless communication device is configured to receive, but not transmit, a S-SSB. In another example, the sidelink capability report may indicate that the first wireless communication device is configured to receive, decode, and transmit a S-SSB. In other examples, the sidelink capability report may indicate that the first wireless communication device is configured only to amplify-and-forward (AF) an S-SSB. Other SSB Tx/Rx capabilities may also be included in the sidelink capability report. 
     In another aspect, the sidelink capability report may include or indicate the first wireless communication device&#39;s capability for physical sidelink control channel (PSCCH) decoding. For example, the sidelink capability report may indicate whether the first wireless communication device is configured to decode a PSCCH, or is only configured for AF of the PSCCH. In another aspect, the sidelink capability report may indicate how many PSCCH decodings and/or transmissions the first wireless communication device can perform within a slot. In another aspect, the sidelink capability report may include or indicate the first wireless communication device&#39;s capability for physical sidelink shared channel (PSSCH) decoding. For example, the sidelink capability report may indicate whether the first wireless communication device is configured to decode a PSSCH, or is only configured for AF of the PSSCH. In another aspect, the sidelink capability report may indicate how many PSSCH decodings and/or transmissions the first wireless communication device can perform within a slot. In another aspect, the sidelink capability report may indicate a number of SCI-2 the first wireless communication device can transmit and/or receive in a slot. In another aspect, the sidelink capability report may indicate whether the first wireless communication device is configured to decode SCI. In another aspect, the sidelink capability report may include or indicate the first wireless communication device&#39;s capability for physical sidelink feedback channel (PSFCH) decoding. For example, the sidelink capability report may indicate whether the first wireless communication device is configured to decode a PSFCH, or is only configured for AF of the PSFCH. In another aspect, the sidelink capability report may indicate the number of PSFCH the first wireless communication device can simultaneously receive and/or decode. In some aspects, the sidelink capability report may indicate that the first wireless communication device is configured to simultaneously transmit M PSFCH communications. In another aspect, the sidelink capability report may indicate that the first wireless communication device is configured to simultaneously receive N PSFCH communications. 
     In another aspect, the sidelink capability report may include or indicate beam capabilities of the first wireless communication device. For example, the sidelink capability report may indicate a number of radiofrequency Tx/Rx panels or antennas that can be used for sidelink transmission. In another aspect, the sidelink capability report may indicate a number of simultaneous transmit/receive beams that can be used for sidelink communication and/or Uu communication with a BS and/or UE. In another aspect, the sidelink capability report may indicate a power class associated with the first wireless communication device. For example, the sidelink communication report may indicate a transmit power class of the first wireless communication device. In another aspect, the sidelink capability report may indicate a frequency granularity of the first wireless communication device. For example, the sidelink capability report may indicate a frequency-selective amplify-and-forward granularity. In another aspect, the sidelink capability report may indicate AF operation for each carrier and/or for each bandwidth part (BWP). In another aspect, the sidelink capability report may indicate AF decoding/processing capabilities for one or more carriers, including a combination or set of carriers. In another aspect, the sidelink capability report may indicate a carrier capability of the first wireless communication device. For example, the sidelink capability report may indicate whether the first wireless communication device is configured for simultaneous operation on Uu and PC5 communication links. Further, the sidelink capability report may indicate whether the first wireless communication device is configured to switch between carriers. The sidelink capability report may indicate a switching delay associated with switching between the carriers. In some aspects, the sidelink capability report may indicate a sensing or measuring capability of the first wireless communication device. For example, the sidelink capability report may indicate whether the first wireless communication device is configured for spectrum sensing or energy detection for autonomous PC5 operation. In another aspect, the sidelink capability report may indicate whether the first wireless communication device is configured to measure reference signal reserve power (RSRP), received signal strength indicator (RSSI), and/or channel busy ratio (CBR) of sidelink signals and channels. In another aspect, the sidelink capability report may indicate the first wireless communication device&#39;s capability for SL-CSI-RS transmission and/or reception. 
     In some aspects, the sidelink capability report may indicate a class or category of repeater. Each class or category of repeater may be associated with one or more of the capabilities described above. For example, the sidelink capability report may indicate a first repeater class associated with a first S-SSB capability, a first decoding (e.g., PSCCH, PSSCH, and/or PSFCH) capability, a first beam capability, a first power class, a first frequency capability, a first frequency granularity, and/or a first sensing measurement capability. In some aspects, the first repeater class may indicate, for example, that AF operation is used for all sidelink channels. In another example, the repeater class may indicate that the first wireless communication device is configured to simultaneously receive and decode M PSFCH, and simultaneously transmit N PSFCH. For example, the second wireless communication device receiving the sidelink capability report may be configured with a table indicating the sidelink capabilities associated with a signaled repeater class. Accordingly, the second wireless communication device may be configured to identify or determine the capabilities of the first wireless communication device based on the indicated repeater class. 
     At step  830 , the first wireless communication device receives a sidelink repeating configuration. The sidelink repeating configuration may be based on the sidelink capability report transmitted at step  820 . In some aspects, the sidelink repeating configuration may indicate parameters or configurations for PC5 repeating operation. In some aspects, the sidelink repeating configuration may indicate on and/or off time periods for repeating operations. For example, the sidelink repeating configuration may indicate semi-static time resources (e.g., frames, slots, sub-slots, symbols, etc.) at which the first wireless communication device will be “on” and performing sidelink repeating operations. In another aspect, the sidelink repeating configuration may indicate frequency carriers, BWPs, and/or other frequency resources for sidelink communication, Uu communication, and/or both sidelink communication and Uu communication. In some aspects, the sidelink repeating configuration may indicate one or more beam directions for receiving Uu communications (e.g., from the BS). In another aspect, the sidelink repeating configuration may indicate one or more beam directions for receiving sidelink signals. In another aspect, the sidelink repeating configuration may indicate one or more beam directions for transmitting Uu and/or sidelink communications. In another aspect, the sidelink repeating configuration may indicate a transmit power configuration for the first wireless communication device. For example, the sidelink repeating configuration may indicate a maximum power and/or a power split for each of a plurality of carriers (e.g., a maximum power for each of the plurality of carriers and/or an aggregate maximum power across the plurality of carriers). The transmit power may be specific to sidelink communications or Uu communications, or may be common for Uu and sidelink communications. 
     At step  840 , the first wireless communication device communicates a first signal based on the sidelink repeating configuration received at step  830 . In some aspects, step  840  may include receiving and/or transmitting the first signal from or to another wireless communication device, such as the second wireless communication device. For example, step  840  may include receiving, from a third wireless communication device, a first sidelink signal, and forwarding the first sidelink signal to the second wireless communication device. In another example, step  840  may include receiving, from the second wireless communication device, a first signal, and forwarding the received first signal to a BS. In some aspects, step  840  may include an amplify-and-forward communication with no signal decoding. In other aspects, step  840  may include receiving and decoding the first signal, and transmitting the decoded first signal to another wireless communication device. As explained above, the first wireless communication device may be used according to different sidelink architectures or modes, for example in an HOT scenario. In this regard, the first wireless communication device may be configured as a repeater or assisting node for relaying communications between a base station and a controlling sidelink node. In other aspects, the first wireless communication device may be configured to relay communications between one or more sidelink UEs and the sidelink controlling UE. In some aspects, the first signal may include control information (e.g., SCI-1, SCI-2). The first signal may include information carried in a PSCCH, for example. In other aspects, the first signal may include sidelink data. For example, the first signal may be carried in a PSSCH. 
     According to the method  800  described above, the first wireless communication device may communicate the first signal with a configuration that accommodates the capabilities of the first wireless communication device. In some aspects, the method  800  described above may allow for a more beneficial use of the first wireless communication device as a repeater or assisting node. By making known to the sidelink controlling node, and/or to the network, the capabilities of the repeater, the architecture and operational mode of the first wireless communication device may be configured and established to obtain more optimal benefits from first wireless communication device. 
       FIG.  9    is a flow diagram of a sidelink method  900  according to some aspects of the present disclosure. Steps of the method  900  can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the steps. In one aspect, a wireless communication device, such as a sidelink UE  115 ,  215 , or  500 , may utilize one or more components, such as the processor  602 , the memory  604 , the sidelink configuration module  608 , the transceiver  610 , the modem  612 , and the one or more antennas  616 , to execute the steps of method  900 . For example, one or more steps of the method  900  may be performed by a controlling sidelink UE or sidelink node, such as the node  207 . In another aspect, a BS, such as one of the BSs  105 ,  205 , or  600  may utilize one or more components, such as the processor  702 , the memory  704 , the sidelink communication module  708 , the transceiver  710 , the modem  712 , and the one or more antennas  716 , to execute the steps of method  900 . The method  900  may employ similar mechanisms as in the methods  300 , and/or  400  described above with respect to  FIGS.  2 A,  2 B,  2 C,  3   , and/or  4 . As illustrated, the method  900  includes a number of enumerated steps, but aspects of the method  900  may include additional steps before, after, and in between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order. 
     At step  910 , the method  900  includes a first wireless communication device receiving, from a second wireless communication device, a connection request. In some aspects, the connection request indicates a request for the second wireless communication device to perform repeater operations in a sidelink network. In some aspects, receiving the connection request may be part of a cell search and/or initial access procedure. In some aspects, step  910  may include performing a random access procedure and establishing a radio resource control (RRC) connection status with a UE or other wireless communication device. For example, in some aspects, the first wireless communication device may transmit system information to the second wireless communication device (e.g., MIB, SIB1), receive a RACH preamble, transmit a RACH response, receive a RRC Setup Request message, transmit a RRC Setup message, receive a RRC Setup Complete message, and receiving NAS Registration indication. Step  910  may further include additional NAS registration, UE capability signaling, and/or registration completion acknowledgement procedures. 
     In other aspects, step  910  may include performing a sidelink discovery procedure. For example, the first wireless communication device may signal its presence to a second wireless communication device, and the second wireless communication device may signal its presence to the first wireless communication device. The sidelink discovery procedure may further include transmitting and/or receiving sidelink control information (SCI) to or from the second wireless communication device. The sidelink discovery procedure may include communicating in a physical sidelink discovery channel (PSDCH), for example. In some aspects, the sidelink discovery procedure may further include transmitting or signaling an identity of the first wireless communication device, and/or receiving a signal indicating an identity of the second wireless communication device. 
     In some aspects, step  910  may further include the first wireless communication device receiving, from the second wireless communication device, one or more repeater configurations and/or capabilities. For example, the first wireless communication device may receive, from the second wireless communication device, a signal indicating that the second wireless communication device supports repeating for sidelink (PC5) and/or Uu communication links. In some aspects, the method  900  may further include the first wireless communication device transmitting a signal authorizing the second wireless communication device to perform sidelink repeating operations during the registration protocol. 
     The registration protocol may include messages communicated between the first wireless communication device and various protocol stacks of the network and their associated components and equipment, including distributed units (DU), central units (CU), and/or the core network (CN). 
     At step  920 , the first wireless communication device receives, from the second wireless communication device, a sidelink capability report. The sidelink capability report may indicate sidelink repeating capabilities of the second wireless communication device. In some aspects, step  920  includes receiving, from the second wireless communication device, a RRC message. For example, step  920  may include the first wireless communication device receiving a RepeaterCapabilitySidelink RRC message. In another example, if the first wireless communication device is a sidelink communication device (e.g., sidelink UE), step  920  may include receiving a PC5RepeaterCapabilitySidelink message. In some aspects, the first wireless communication device receives the sidelink capability report in response to the second wireless communication device being registered to the first wireless communication device, or to a network associated with the first wireless communication device. 
     The sidelink capability report may include or indicate one or more capabilities of the second wireless communication device associated with repeating operations and/or sidelink communications. For example, the sidelink capability report may include or indicate a sidelink synchronization signal block (S-SSB) capability. The S-SSB capability may include or indicate the second wireless communication device&#39;s capability to transmit and/or receive a S-SSB. In some aspects, the S-SSB capability may include or indicate the second wireless communication device&#39;s capability to decode and/or amplify and forward a S-SSB. For example, the sidelink capability report may indicate that the second wireless communication device is configured to receive, but not transmit, a S-SSB. In another example, the sidelink capability report may indicate that the second wireless communication device is configured to receive, decode, and transmit a S-SSB. In other examples, the sidelink capability report may indicate that the second wireless communication device is configured only to amplify-and-forward (AF) an S-SSB. Other SSB Tx/Rx capabilities may also be included in the sidelink capability report. 
     In another aspect, the sidelink capability report may include or indicate the second wireless communication device&#39;s capability for physical sidelink control channel (PSCCH) decoding. For example, the sidelink capability report may indicate whether the second wireless communication device is configured to decode a PSCCH, or is only configured for AF of the PSCCH. In another aspect, the sidelink capability report may indicate how many PSCCH decodings and/or transmissions the second wireless communication device can perform within a slot. In another aspect, the sidelink capability report may include or indicate the second wireless communication device&#39;s capability for physical sidelink shared channel (PSSCH) decoding. For example, the sidelink capability report may indicate whether the second wireless communication device is configured to decode a PSSCH, or is only configured for AF of the PSSCH. In another aspect, the sidelink capability report may indicate how many PSSCH decodings and/or transmissions the second wireless communication device can perform within a slot. In another aspect, the sidelink capability report may indicate a number of SCI-2 the second wireless communication device can transmit and/or receive in a slot. In another aspect, the sidelink capability report may indicate whether the second wireless communication device is configured to decode SCI. In another aspect, the sidelink capability report may include or indicate the second wireless communication device&#39;s capability for physical sidelink feedback channel (PSFCH) decoding. For example, the sidelink capability report may indicate whether the second wireless communication device is configured to decode a PSFCH, or is only configured for AF of the PSFCH. In another aspect, the sidelink capability report may indicate the number of PSFCH the second wireless communication device can simultaneously receive and/or decode. In some aspects, the sidelink capability report may indicate that the second wireless communication device is configured to simultaneously transmit M PSFCH communications. In another aspect, the sidelink capability report may indicate that the second wireless communication device is configured to simultaneously receive N PSFCH communications. 
     In another aspect, the sidelink capability report may include or indicate beam capabilities of the second wireless communication device. For example, the sidelink capability report may indicate a number of radiofrequency Tx/Rx panels or antennas that can be used for sidelink transmission. In another aspect, the sidelink capability report may indicate a number of simultaneous transmit/receive beams that can be used for sidelink communication and/or Uu communication with a BS and/or a UE. In another aspect, the sidelink capability report may indicate a power class associated with the second wireless communication device. For example, the sidelink communication report may indicate a transmit power class of the second wireless communication device. In another aspect, the sidelink capability report may indicate a frequency granularity of the second wireless communication device. For example, the sidelink capability report may indicate a frequency-selective amplify-and-forward granularity. In another aspect, the sidelink capability report may indicate AF operation for each carrier and/or for each bandwidth part (BWP). In another aspect, the sidelink capability report may indicate AF decoding/processing capabilities for one or more carriers, including a combination or set of carriers. In another aspect, the sidelink capability report may indicate a carrier capability of the second wireless communication device. For example, the sidelink capability report may indicate whether the second wireless communication device is configured for simultaneous operation on Uu and PC5 communication links. Further, the sidelink capability report may indicate whether the second wireless communication device is configured to switch between carriers. The sidelink capability report may indicate a switching delay associated with switching between the carriers. In some aspects, the sidelink capability report may indicate a sensing or measuring capability of the second wireless communication device. For example, the sidelink capability report may indicate whether the second wireless communication device is configured for spectrum sensing or energy detection for autonomous PC5 operation. In another aspect, the sidelink capability report may indicate whether the second wireless communication device is configured to measure reference signal reserve power (RSRP), received signal strength indicator (RSSI), and/or channel busy ratio (CBR) of sidelink signals and channels. In another aspect, the sidelink capability report may indicate the second wireless communication device&#39;s capability for SL-CSI-RS transmission and/or reception. 
     In some aspects, the sidelink capability report may indicate a class or category of repeater. Each class or category of repeater may be associated with one or more of the capabilities described above. For example, the sidelink capability report may indicate a first repeater class associated with a first S-SSB capability, a first decoding (e.g., PSCCH, PSSCH, and/or PSFCH) capability, a first beam capability, a first power class, a first frequency capability, a first frequency granularity, and/or a first sensing measurement capability. In some aspects, the first repeater class may indicate, for example, that AF operation is used for all sidelink channels. In another example, the repeater class may indicate that the second wireless communication device is configured to simultaneously receive and decode M PSFCH, and simultaneously transmit N PSFCH. For example, the first wireless communication device receiving the sidelink capability report may be configured with a table indicating the sidelink capabilities associated with a signaled repeater class. Accordingly, the first wireless communication device may be configured to identify or determine the capabilities of the second wireless communication device based on the indicated repeater class. 
     Step  930 , the first wireless communication device transmits a sidelink repeating configuration. The sidelink repeating configuration may be based on the sidelink capability report received at step  920 . In some aspects, the sidelink repeating configuration may indicate parameters or configurations for PC5 repeating operation. In some aspects, the sidelink repeating configuration may indicate on and/or off time periods for repeating operations. For example, the sidelink repeating configuration may indicate semi-static time resources (e.g., frames, slots, sub-slots, symbols, etc.) at which the second wireless communication device will be “on” and performing sidelink repeating operations. In another aspect, the sidelink repeating configuration may indicate frequency carriers, BWPs, and/or other frequency resources for sidelink communication, Uu communication, and/or both sidelink communication and Uu communication. In some aspects, the sidelink repeating configuration may indicate one or more beam directions for receiving Uu communications (e.g., from the BS). In another aspect, the sidelink repeating configuration may indicate one or more beam directions for receiving sidelink signals. In another aspect, the sidelink repeating configuration may indicate one or more beam directions for transmitting Uu and/or sidelink communications. In another aspect, the sidelink repeating configuration may indicate a transmit power configuration for the second wireless communication device. For example, the sidelink repeating configuration may indicate a maximum power and/or a power split for each of a plurality of carriers (e.g., a maximum power for each of the plurality of carriers and/or an aggregate maximum power across the plurality of carriers). The transmit power may be specific to sidelink communications or Uu communications, or may be common for Uu and sidelink communications. 
     In some aspects, the method  900  further includes the first wireless communication device receiving, from the second wireless communication device, a first signal based on the sidelink repeating configuration transmitted at step  930 . In some aspects, the first wireless communication device may receive the first signal from another wireless communication device via the second wireless communication device. For example, the second wireless communication device may include a repeater. The first wireless communication device may receive, from a third wireless communication device via the repeater, a first sidelink. In another example, the method  900  may include transmitting, to a third wireless communication device via the second wireless communication device, a first signal. 
     As explained above, the first wireless communication device may be used according to different sidelink architectures or modes, for example in an IIOT scenario. In this regard, the first wireless communication device may be configured as a controlling sidelink UE. In other aspects, the second wireless communication device may be configured to relay communications between one or more sidelink UEs and the sidelink controlling UE. In some aspects, the first signal may include control information (e.g., SCI-1, SCI-2). In other aspects, the first signal may include sidelink data. For example, the first signal may be carried in a PSSCH. 
     Example Aspects of the Present Disclosure 
     Aspect 1. A method of wireless communication performed by a first wireless communication device, comprising: initiating a registration protocol for performing repeater operations for sidelink communications; transmitting, to a second wireless communication device, a sidelink capability report indicating sidelink repeating capabilities of the first wireless communication device; receiving a sidelink repeating configuration based on the sidelink capability report; and communicating a first signal based on the sidelink repeating configuration. 
     Aspect 2. The method of aspect 1, wherein the second wireless communication device comprises a base station (BS), and wherein the initiating the registration protocol comprises transmitting a registration request to the BS. 
     Aspect 3. The method of aspect 2, wherein the receiving the sidelink repeating configuration comprises receiving the sidelink repeating configuration from the BS. 
     Aspect 4. The method of aspect 2, wherein the receiving the sidelink repeating configuration comprises receiving the sidelink repeating configuration from a sidelink user equipment (UE). 
     Aspect 5. The method of any of aspects 2-4, wherein the sidelink capability report indicates at least one of: a sidelink synchronization signal block decoding capability; a sidelink channel decoding capability; a sidelink beam capability; a power class; a frequency granularity; a simultaneous sidelink and Uu communication capability; a channel sensing capability; or a repeater type index. 
     Aspect 6. The method of aspect 5, wherein the sidelink capability report indicates at least the sidelink channel decoding capability and the sidelink transmission capability, the sidelink channel decoding capability including one or more of: a sidelink control channel decoding capability; a sidelink data channel decoding capability; a sidelink feedback channel decoding capability; a number of simultaneous decodings for one or more sidelink channels; or a number of simultaneous transmissions for one or more sidelink channels. 
     Aspect 7. The method of aspect 1, wherein the second wireless communication device comprises a sidelink user equipment (UE), and wherein the initiating the registration protocol comprises initiating a sidelink discovery protocol. 
     Aspect 8. The method of aspect 7, wherein: the initiating the registration protocol comprises transmitting, to the sidelink UE, an indication of a repeater type of the first wireless communication device; and the method further comprises: receiving, from the sidelink UE, a sidelink capability report request based on the repeater type; and the transmitting the sidelink capability report is based on the sidelink capability report request. 
     Aspect 9. The method of any of aspects 7 or 8, wherein the sidelink capability report indicates at least one of: a sidelink synchronization signal block decoding capability; a sidelink channel decoding capability; a sidelink beam capability; a power class; a frequency granularity; a simultaneous sidelink and Uu communication capability; a channel sensing capability; or a repeater type index. 
     Aspect 10. The method of any of aspects 7-9, wherein the sidelink capability report is based on at least a Uu connection status of the first wireless communication device with a base station (BS). 
     Aspect 11. The method of any of aspects 7-11, wherein the transmitting the sidelink capability report is based on the sidelink UE being authorized by one or more higher layers of a protocol stack. 
     Aspect 12. The method of aspect 1, wherein the sidelink repeating configuration indicates one or more of: configured time resources for sidelink repeating; frequency resources associated with sidelink communications; frequency resources associated with Uu communications; receive beam directions; transmit beam directions; or transmit power. 
     Aspect 13. A method of wireless communication performed by a first wireless communication device, comprising: receiving, from a second wireless communication device, a connection request; receiving, from the second wireless communication device, a sidelink capability report indicating sidelink repeating capabilities of the second wireless communication device; and transmitting, based on the sidelink capability report, a sidelink repeating configuration. 
     Aspect 14. The method of aspect 13, wherein the sidelink capability report indicates at least one of: a sidelink synchronization signal block decoding capability; a sidelink channel decoding capability; a sidelink beam capability; a power class; a frequency granularity; a simultaneous sidelink and Uu communication capability; a channel sensing capability; or a repeater type index. 
     Aspect 15. The method of aspect 14, wherein the sidelink capability report indicates at least the sidelink channel decoding capability and the sidelink transmission capability, and wherein the sidelink channel decoding capability includes one or more of: a sidelink control channel decoding capability; a sidelink data channel decoding capability; a sidelink feedback channel decoding capability; a number of simultaneous decodings for one or more sidelink channels; or a number of simultaneous transmissions for one or more sidelink channels. 
     Aspect 16. The method of any of aspects 13-15, wherein: the first wireless communication device comprises a sidelink user equipment (UE); the method further comprises performing a sidelink discovery protocol; the sidelink discovery protocol comprises the receiving the connection request; the performing the sidelink discovery protocol comprises receiving, from the second wireless communication device, a signal indicating a repeater type of the second wireless communication device; and the method further comprises transmitting, to the second wireless communication device, a sidelink capability report request based on the repeater type. 
     Aspect 17. The method of any of aspects 13-16, wherein the sidelink repeating configuration indicates one or more of: configured time resources for sidelink repeating; frequency resources associated with sidelink communications; frequency resources associated with Uu communications; receive beam directions; transmit beam directions; or transmit power. 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, or any combination thereof. 
     Aspect 18. A first wireless communication device comprising a processor and a transceiver, wherein the processor and the transceiver are configured to perform the actions of any of aspects 1-12. 
     Aspect 19. A first wireless communication device comprising a processor and a transceiver, wherein the processor and the transceiver are configured to perform the actions of any of aspects 13-17. 
     Aspect 20. A non-transitory computer-readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor to cause a first wireless communication device to: initiate a registration protocol for performing repeater operations for sidelink communications; transmit, to a second wireless communication device, a sidelink capability report indicating sidelink repeating capabilities of the first wireless communication device; receive a sidelink repeating configuration based on the sidelink capability report; and communicate a first signal based on the sidelink repeating configuration. 
     Aspect 21. A non-transitory computer-readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor to cause a first wireless communication device to: receive, from a second wireless communication device, a connection request; receive, from the second wireless communication device, a sidelink capability report indicating sidelink repeating capabilities of the second wireless communication device; and transmit, based on the sidelink capability report, a sidelink repeating configuration. 
     Aspect 22. A first wireless communication device comprises means for performing the actions of any of claims  1 - 12 . 
     Aspect 23. A first wireless communication device comprises means for performing the actions of any of claims  13 - 17 . 
     The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A 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 executed by a processor, firmware, 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 computer-readable medium. Other examples and implementations are within the scope 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 processor, hardware, firmware, 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. Also, as used herein, including in the claims, “or” as used in a list of items (for example, a list of items prefaced by a phrase such as “at least one of” or “one or more of”) indicates an inclusive list such that, for example, a list of [at least one of A, B, or C] means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). 
     As those of some skill in this art will by now appreciate and depending on the particular application at hand, many modifications, substitutions and variations can be made in and to the materials, apparatus, configurations and methods of use of the devices of the present disclosure without departing from the spirit and scope thereof. In light of this, the scope of the present disclosure should not be limited to that of the particular embodiments illustrated and described herein, as they are merely by way of some examples thereof, but rather, should be fully commensurate with that of the claims appended hereafter and their functional equivalents.