Layer 2 relay unicast link establishment

Abstract

Various aspects of the present disclosure generally relate to wireless communications. In some aspects, a remote user equipment (UE) may send a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service to a relay UE; receive a message from the relay UE indicating that the relay UE accepts the layer 2 relay service associated with the relay service code; establish a radio access signaling radio bearer (SRB) for the layer 2 relay service using a remote UE radio access signaling radio bearer (SRB) configuration; and communicate via the radio access SRB. A number of other aspects are provided.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 62 / 986,329, filed on March 6, 2020, entitled “LAYER2RELAY UNICAST LINK SETUP,” and U.S. Non-Provisional Patent Application No. 17 / 176,785, filed on February 16, 2021, entitled “LAYER 2RELAY UNICAST LINK SETUP,” which are hereby expressly incorporated herein by reference. Technical Field

[0003] Aspects of the present disclosure relate generally to wireless communications and to techniques and apparatus for layer 2 relay unicast link establishment. Background Art

[0004] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple access technologies that can support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and long term evolution (LTE). LTE / LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP).

[0005] A wireless network may include multiple base stations (BSs) that can support communications for multiple user equipments (UEs). The UE may communicate with the BS via a downlink and an uplink. The downlink (or forward link) refers to a communication link from the BS to the UE, and the uplink (or reverse link) refers to a communication link from the UE to the BS. As will be described in more detail herein, the BS may be referred to as a Node B, gNB, Access Point (AP), Radio Head, Transmit Receive Point (TRP), New Radio (NR) BS, 5G Node B, etc.

[0006] The above-mentioned multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user devices to communicate at municipal, national, regional and even global levels. NR, which can also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and better integrating with other open standards using orthogonal frequency division multiplexing (OFDM) (CP-OFDM) with cyclic prefix (CP) on the downlink (DL), using CP-OFDM and / or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), and supporting beamforming, multiple-input multiple-output (MIMO) antenna technology and carrier aggregation. As the demand for mobile broadband access continues to grow, further improvements to LTE, NR and other radio access technologies remain useful. Summary of the invention

[0007] In some aspects, a wireless communication method performed by a remote user equipment (UE) may include: sending a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service to a relay UE; receiving a message from the relay UE indicating that the relay UE accepts the layer 2 relay service associated with the relay service code; establishing a radio access signaling radio bearer (SRB) for the layer 2 relay service using a remote UE radio access signaling radio bearer (SRB) configuration; and communicating via the radio access SRB.

[0008] In some aspects, a wireless communication method performed by a relay UE may include: receiving a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service from a remote UE; providing a message to the remote UE indicating whether the relay UE accepts the layer 2 relay service based at least in part on the relay service code; and when the relay UE accepts the layer 2 relay service associated with the relay service code, establishing a radio access SRB for the layer 2 relay service with the remote UE using a remote UE radio access SRB configuration.

[0009] In some aspects, a method of wireless communication performed by a base station may include: receiving an indication from a relay UE that the relay UE supports layer 2 relay services; sending a relay configuration to the relay UE based at least in part on the indication; and communicating with a remote UE via the relay UE based at least in part on the relay configuration.

[0010] In some aspects, a remote UE for wireless communication may include a memory and one or more processors operably coupled to the memory. The memory and the one or more processors may be configured to: send a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service to a relay UE; receive a message from the relay UE indicating that the relay UE accepts the layer 2 relay service associated with the relay service code; establish a radio access SRB for the layer 2 relay service using a remote UE radio access SRB configuration; and communicate via the radio access SRB.

[0011] In some aspects, a relay UE for wireless communication may include a memory and one or more processors operably coupled to the memory. The memory and the one or more processors may be configured to: receive a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service from a remote UE; provide a message indicating whether the relay UE accepts the layer 2 relay service to the remote UE based at least in part on the relay service code; and when the relay UE accepts the layer 2 relay service associated with the relay service code, establish a radio access SRB for the layer 2 relay service with the remote UE using the remote UE radio access SRB configuration.

[0012] In some aspects, a base station for wireless communication may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: receive an indication from a relay UE that the relay UE supports layer 2 relay services; send a relay configuration to the relay UE based at least in part on the indication; and communicate with a remote UE via the relay UE based at least in part on the relay configuration.

[0013] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a remote UE, may cause the one or more processors to: send a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service to a relay UE; receive a message from the relay UE indicating that the relay UE accepts the layer 2 relay service associated with the relay service code; establish a radio access SRB for the layer 2 relay service using the remote UE radio access SRB configuration; and communicate via the radio access SRB.

[0014] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a relay UE, may cause the one or more processors to: receive a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service from a remote UE; provide a message to the remote UE indicating whether the relay UE accepts the layer 2 relay service based at least in part on the relay service code; and when the relay UE accepts the layer 2 relay service associated with the relay service code, establish a radio access SRB for the layer 2 relay service with the remote UE using the remote UE radio access SRB configuration.

[0015] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a base station, may cause the one or more processors to: receive an indication from a relay UE that the relay UE supports layer 2 relay services; send a relay configuration to the relay UE based at least in part on the indication; and communicate with a remote UE via the relay UE based at least in part on the relay configuration.

[0016] In some aspects, an apparatus for wireless communication may include: a component for sending a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service to a relay UE; a component for receiving a message from the relay UE indicating that the relay UE accepts the layer 2 relay service associated with the relay service code; a component for establishing a radio access SRB for the layer 2 relay service using a remote UE radio access SRB configuration; and a component for communicating via the radio access SRB.

[0017] In some aspects, an apparatus for wireless communication may include: a component for receiving a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service from a remote UE; a component for providing a message to the remote UE indicating whether the relay UE accepts the layer 2 relay service based at least in part on the relay service code; and a component for establishing a radio access SRB for the layer 2 relay service with the remote UE using a remote UE radio access SRB configuration when the relay UE accepts the layer 2 relay service associated with the relay service code.

[0018] In some aspects, an apparatus for wireless communication may include: a component for receiving an indication from a relay UE that the relay UE supports layer 2 relay services; a component for sending a relay configuration to the relay UE based at least in part on the indication; and a component for communicating with a remote UE via the relay UE based at least in part on the relay configuration.

[0019] Aspects generally include methods, apparatus, systems, computer program products, non-transitory computer-readable media, user equipment, base stations, wireless communication devices, and processing systems as generally described herein with reference to and illustrated by the accompanying drawings and description.

[0020] The foregoing has outlined rather broadly the features and technical advantages of examples according to the present disclosure so that the following detailed description may be better understood. Additional features and advantages will be described below. The disclosed concepts and specific examples may be easily used as a basis for modifying or designing other structures for achieving the same purpose of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The features of the concepts disclosed herein, their organization and methods of operation, and related advantages may be better understood through the following description when considered in conjunction with the accompanying drawings. Each of the accompanying drawings is provided for the purpose of illustration and description and not as a definition of limitations to the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order that the above-mentioned features of the present disclosure may be understood in detail, a more specific description of the content briefly summarized above may be provided by reference to various aspects, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate certain typical aspects of the present disclosure and therefore should not be considered as limiting the scope thereof, as the description may allow for other equivalent aspects. The same reference numerals in different drawings may identify the same or similar elements.

[0022] Figure 1 is a diagram illustrating an example of a wireless network according to the present disclosure.

[0023] Figure 2 is a diagram illustrating an example of a base station communicating with a UE in a wireless network according to the present disclosure.

[0024] Figure 3 is a diagram illustrating an example of a control plane protocol architecture for layer 2 UE to network relay according to the present disclosure.

[0025] Figure 4 is a diagram illustrating an example of a user plane protocol architecture for layer 2 UE to network relay according to the present disclosure.

[0026] Figure 5 is a diagram illustrating an example of a first discovery model for a UE performing sidelink communication according to the present disclosure.

[0027] Figure 6 is a diagram illustrating an example of a second discovery model for a UE performing sidelink communication according to the present disclosure.

[0028] Figure 7is a diagram illustrating an example of registration and establishment of a sidelink connection of a UE for performing sidelink communication according to the present disclosure.

[0029] Figure 8 is a diagram illustrating an example of a configuration of a layer 2 relay service on a side link associated with a connection establishment according to the present disclosure.

[0030] Fig. 9 is a diagram illustrating an example of a configuration of a layer 2 relay service on a side link associated with a connection modification according to the present disclosure.

[0031] Fig.10 is a diagram illustrating an example process performed, for example, by a user device according to the present disclosure.

[0032] Fig.11 is a diagram illustrating an example process performed, for example, by a user device according to the present disclosure.

[0033] Fig.12 is a diagram illustrating an example process performed, for example, by a base station according to the present disclosure. DETAILED DESCRIPTION

[0034] The various aspects of the present disclosure are described more fully below with reference to the accompanying drawings. However, the present disclosure can be embodied in many different forms and should not be interpreted as being limited to any specific structure or function presented throughout the present disclosure. On the contrary, these aspects are provided so that the present disclosure will be comprehensive and complete, and the scope of the present disclosure will be fully conveyed to those skilled in the art. Based on the teachings herein, it should be understood by those skilled in the art that the scope of the present disclosure is intended to cover any aspect of the present disclosure disclosed herein, whether they are implemented independently of any other aspect of the present disclosure or implemented in combination with any other aspect of the present disclosure. For example, any number of aspects set forth herein can be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover such a device or method, that is, the device or method is practiced using other structures, functions, or structures and functions other than the various aspects of the present disclosure set forth herein or different from the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the present disclosure disclosed herein can be embodied by one or more elements of the claims.

[0035] Several aspects of telecommunication systems will now be presented with reference to various devices and techniques. These devices and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms and / or the like (collectively referred to as "elements"). These elements may be implemented using hardware, software, or a combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0036] It should be noted that although various aspects may be described herein using terminology generally associated with 5G or NR radio access technologies (RATs), various aspects of the present disclosure may be applied to other RATs, such as 3G RATs, 4G RATs, and / or RATs after 5G (e.g., 6G).

[0037] Figure 1 is a diagram illustrating an example of a wireless network 100 according to the present disclosure. The wireless network 100 may be or may include elements of a 5G (NR) network, an LTE network, etc. The wireless network 100 may include a plurality of base stations 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities. A base station (BS) is an entity that communicates with a user equipment (UE) and may also be referred to as an NR BS, a Node B, a gNB, a 5G Node B (NB), an access point, a transmit receive point (TRP), etc. Each BS may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to a coverage area of ​​a BS and / or a BS subsystem serving the coverage area, depending on the context in which the term is used.

[0038] A BS may provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access to UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access to UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access to UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG)). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In Figure 1 In the example shown, BS 110a may be a macro BS for macro cell 102a, BS 110b may be a pico BS for pico cell 102b, and BS 110c may be a femto BS for femto cell 102c. A BS may support one or more (e.g., three) cells. The terms "eNB", "base station", "NR BS", "gNB", "TRP", "AP", "Node B", "5G NB", and "cell" may be used interchangeably herein.

[0039] In some aspects, a cell may not necessarily be fixed, and the geographic area of ​​the cell may move depending on the location of the mobile BS. In some aspects, the BSs may be interconnected with each other and / or with one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces (such as direct physical connections or virtual networks) using any suitable transmission network.

[0040] The wireless network 100 may also include a relay station. A relay station is an entity that can receive transmissions of data from an upstream station (e.g., a BS or a UE) and transmit transmissions of data to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that can relay transmissions for other UEs. Figure 1 In the example shown, relay BS 110d may communicate with macro BS 110a and UE 120d to facilitate communication between BS 110a and UE 120d. A relay BS may also be referred to as a relay station, relay base station, relay, or the like.

[0041] The wireless network 100 may be a heterogeneous network including different types of BSs, such as a macro BS, a pico BS, a femto BS, a relay BS, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different effects on interference in the wireless network 100. For example, a macro BS may have a higher transmit power level (e.g., 5 watts to 40 watts), while a pico BS, a femto BS, and a relay BS may have a lower transmit power level (e.g., 0.1 watt to 2 watts).

[0042] The network controller 130 may be coupled to a set of BSs and may provide coordination and control for these BSs. The network controller 130 may communicate with the BSs via a backhaul. The BSs may also communicate with each other directly or indirectly via a wireless or wired backhaul.

[0043] UE 120 (e.g., 120a, 120b, 120c) may be dispersed throughout the wireless network 100, and each UE may be fixed or mobile. UE may also be referred to as an access terminal, terminal, mobile station, subscriber unit, station, etc. UE may be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or instrument, a biosensor / device, a wearable device (smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device, or satellite radio, etc.), a vehicle component or sensor, a smart meter / sensor, an industrial manufacturing device, a global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium.

[0044] Some UEs may be considered as machine type communication (MTC) or evolved or enhanced machine type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, and / or location tags that can communicate with a base station, another device (e.g., a remote device), or some other entity. A wireless node may provide, for example, a connection for or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered as Internet of Things (IoT) devices, and / or may be implemented as NB-IoT (narrowband Internet of Things) devices. Some UEs may be considered as customer premises equipment (CPE). UE 120 may be included inside a housing that houses components of UE 120 (such as a processor component and / or a memory component). In some aspects, a processor component and a memory component may be coupled together. For example, a processor component (e.g., one or more processors) and a memory component (e.g., a memory) may be operably coupled, communicatively coupled, electronically coupled, and / or electrically coupled.

[0045] Generally, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific RAT and can operate on one or more frequencies. RAT can also be referred to as radio technology, air interface, etc. Frequency can also be referred to as carrier, frequency channel, etc. Each frequency can support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0046] In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly (e.g., without using base station 110 as an intermediary to communicate with each other) using one or more side link channels. For example, UE 120 may communicate using peer-to-peer (P2P) communication, device-to-device (D2D) communication, vehicle-to-everything (V2X) protocol (e.g., which may include vehicle-to-vehicle (V2V) protocol or vehicle-to-infrastructure (V2I) protocol), and / or mesh network. In this case, UE 120 may perform scheduling operations, resource selection operations, and / or other operations described elsewhere herein as being performed by base station 110.

[0047] Devices of the wireless network 100 may communicate using an electromagnetic spectrum, which may be subdivided into various categories, bands, channels, etc. based on frequency or wavelength. For example, devices of the wireless network 100 may communicate using an operating band having a first frequency range (FR1), which may span from 410 MHz to 7.125 GHz, and / or may communicate using an operating band having a second frequency range (FR2), which may span from 24.25 GHz to 52.6 GHz. Frequencies between FR1 and FR2 are sometimes referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to as a "sub-6 GHz" band. Similarly, FR2 is often referred to as a "millimeter wave" band, although it is different from the extremely high frequency (EHF) band (30 GHz–300 GHz) recognized as a "millimeter wave" band by the International Telecommunication Union (ITU). Therefore, if used herein, unless otherwise expressly stated, it should be understood that the term "sub-6 GHz" and the like can broadly refer to frequencies less than 6 GHz, frequencies within FR1, and / or mid-band frequencies (e.g., greater than 7.125 GHz). Similarly, if used herein, unless otherwise expressly stated, it should be understood that the term "millimeter wave" and the like can broadly refer to frequencies within the EHF band, frequencies within FR2, and / or mid-band frequencies (e.g., less than 24.25 GHz). It is contemplated that the frequencies included in FR1 and FR2 can be modified, and the techniques described herein are applicable to those modified frequency ranges.

[0048] As pointed out above, Figure 1 are provided as examples. Other examples can be found in the Figure 1 Different than described.

[0049] Figure 2is a diagram illustrating an example 200 of a base station 110 communicating with a UE 120 in a wireless network 100 according to the present disclosure. The base station 110 may be equipped with T antennas 234a through 234t, and the UE 120 may be equipped with R antennas 252a through 252r, where in general T≥1 and R≥1.

[0050] At the base station 110, the transmit processor 220 may receive data for one or more UEs from the data source 212, select one or more modulation and coding schemes (MCS) for each UE based at least in part on a channel quality indicator (CQI) received from the UE, process (e.g., encode and modulate) data for each UE based at least in part on the (multiple) MCS selected for the UE, and provide data symbols for all UEs. The transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI)) and control information (e.g., CQI requests, grants, and / or upper layer signaling), and provide overhead symbols and control symbols. The transmit processor 220 may also generate reference symbols for reference signals (e.g., cell-specific reference signals (CRS) or demodulation reference signals (DMRS)) and synchronization signals (e.g., primary synchronization signals (PSS) or secondary synchronization signals (SSS)). If applicable, a transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols, and may provide T output symbol streams to T modulators (MOD) 232a through 232t. Each modulator 232 may process a corresponding output symbol stream (e.g., for OFDM) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. The T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 234t, respectively.

[0051] At the UE 120, antennas 252a to 252r may receive downlink signals from the base station 110 and / or other base stations, and may provide received signals to demodulators (DEMODs) 254a to 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) the received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM) to obtain received symbols. The MIMO detector 256 may obtain received symbols from all R demodulators 254a to 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. The receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for the UE 120 to the data sink 260, and provide decoded control information and system information to the controller / processor 280. The term "controller / processor" may refer to one or more controllers, one or more processors, or a combination thereof. The channel processor may determine a reference signal received power (RSRP) parameter, a received signal strength indicator (RSSI) parameter, a reference signal received quality (RSRQ) parameter, a channel quality indicator (CQI) parameter, etc. In some aspects, one or more components of UE 120 may be included in a housing.

[0052] The network controller 130 may include a communication unit 294, a controller / processor 290, and a memory 292. The network controller 130 may include, for example, one or more devices in a core network. The network controller 130 may communicate with the base station 110 via the communication unit 294.

[0053] Antennas (e.g., antennas 234a to 234t and / or antennas 252a to 252r) may include, or may be included in, one or more antenna panels, antenna groups, antenna element sets, and / or antenna arrays, etc. Antenna panels, antenna groups, antenna element sets, and / or antenna arrays may include one or more antenna elements. Antenna panels, antenna groups, antenna element sets, and / or antenna arrays may include coplanar antenna element sets and / or non-coplanar antenna element sets. Antenna panels, antenna groups, antenna element sets, and / or antenna arrays may include antenna elements within a single housing and / or antenna elements within multiple housings. Antenna panels, antenna groups, antenna element sets, and / or antenna arrays may include antenna elements coupled to one or more transmitting and / or receiving components (such as Figure 2 One or more antenna elements of one or more components).

[0054] On the uplink, at the UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information from a controller / processor 280 (e.g., for reports including RSRP, RSSI, RSRQ, and / or CQI). The transmit processor 264 may also generate reference symbols for one or more reference signals. If applicable, the symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266, further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM or CP-OFDM), and transmitted to the base station 110. In some aspects, the modulator and demodulator (e.g., MOD / DEMOD 254) of the UE 120 may be included in a modem of the UE 120. In some aspects, the UE 120 includes a transceiver. The transceiver may include any combination of antenna(s) 252, modulators and / or demodulators 254, MIMO detectors 256, receive processors 258, transmit processors 264, and / or TX MIMO processors 266. The transceiver may be used by a processor (e.g., controller / processor 280) and memory 282 to perform aspects of any of the methods described herein, for example, as described with reference to Figure 3-Figure 12 as described.

[0055] At the base station 110, uplink signals from the UE 120 and other UEs may be received by the antenna 234, processed by the demodulator 232, detected by the MIMO detector 236 (if applicable), and further processed by the receive processor 238 to obtain decoded data and control information sent by the user equipment 120. The receive processor 238 may provide the decoded data to the data sink 239 and provide the decoded control information to the controller / processor 240. The base station 110 may include a communication unit 244 and communicate with the network controller 130 via the communication unit 244. The base station 110 may include a scheduler 246 to schedule the UE 120 for downlink and / or uplink communications. In some aspects, the base station 110 includes a transceiver. The transceiver may include any combination of antenna(s) 234, modulators and / or demodulators 232, MIMO detectors 236, receive processors 238, transmit processors 220, and / or TX MIMO processors 230. The transceiver may be used by a processor (eg, controller / processor 240) and memory 242 to perform aspects of any of the methods described herein, for example, as described with reference to Figure 3-Figure 12 as described.

[0056] The controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2Any other components of the base station 110 may perform one or more techniques associated with layer 2 relay unicast link establishment, as described in more detail elsewhere herein. For example, the controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2 Any other component(s) may perform or direct e.g. Fig.10 Processing 1000, Fig.11 Processing 1100, Fig.12 1200 and / or operations of other processes as described herein. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. In some aspects, memory 242 and / or memory 282 may include a non-transitory computer-readable medium storing one or more instructions (e.g., code and / or program code) for wireless communication. For example, one or more instructions, when executed by one or more processors of base station 110 and / or UE 120 (e.g., directly, or after compilation, conversion and / or interpretation), may cause one or more processors, UE 120 and / or base station 110 to perform or direct, for example, Fig.10 Processing 1000, Fig.11 Processing 1100, Fig.12 The process 1200 and / or operations of other processes as described herein. In some aspects, executing instructions may include running instructions, converting instructions, compiling instructions, and / or interpreting instructions, etc.

[0057] In some aspects, UE 120 may include means for sending a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service to a relay UE; means for receiving a message from the relay UE indicating that the relay UE accepts the layer 2 relay service associated with the relay service code; means for establishing a radio access SRB for the layer 2 relay service using a remote UE radio access SRB configuration; means for communicating via the radio access SRB; means for receiving the remote UE radio access SRB configuration from the relay UE; means for receiving a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service from the remote UE A component for providing a message to a remote UE indicating whether the relay UE accepts the layer 2 relay service based at least in part on the relay service code; a component for establishing a radio access SRB for the layer 2 relay service with the remote UE using the remote UE radio access SRB configuration when the relay UE accepts the layer 2 relay service associated with the relay service code; a component for providing the remote UE radio access SRB configuration to the remote UE; a component for providing an indication to the base station that the relay UE supports the layer 2 relay service; a component for receiving a relay configuration from the base station based at least in part on the indication, etc. In some aspects, these components may include a combination of Figure 2 One or more components of UE 120 are depicted, such as controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, etc.

[0058] In some aspects, the base station 110 may include a component for receiving an indication from the relay UE that the relay UE supports layer 2 relay services; a component for sending a relay configuration to the relay UE based at least in part on the indication; a component for communicating with the remote UE via the relay UE based at least in part on the relay configuration, etc. In some aspects, these components may include a combination of Figure 2 One or more components of base station 110 are depicted, such as antenna 234, DEMOD 232, MIMO detector 236, receive processor 238, controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna 234, and the like.

[0059] Although Figure 2 The blocks in the 200 and 210 are illustrated as distinct components, but the functionality described above with respect to the blocks may be implemented in a single hardware, software, or combined component or in various combinations of components. For example, the functionality described with respect to the transmit processor 264, the receive processor 258, and / or the TX MIMO processor 266 may be performed by or under the control of the controller / processor 280.

[0060] As pointed out above, Figure 2 are provided as examples. Other examples can be found in the Figure 2 The difference described

[0061] Figure 3 is a diagram illustrating an example of a control plane protocol architecture 300 for a layer 2 UE to network relay according to the present disclosure. Figure 4 305 and 405, and a relay UE (e.g., UE 120) as shown in FIG. 406 .

[0062] like Figure 3As shown, in the control plane, there may be a PC5 interface (e.g., a side link interface) between the remote UE and the relay UE, a Uu interface between the relay UE and the next generation radio access network (NG-RAN, also referred to herein as 5G access network (5G-AN)), an N2 interface between the NG-RAN and the access and mobility management function (AMF) of the control plane protocol architecture 300, and an N11 interface between the AMF and the session management function (SMF).

[0063] like Figure 4 As shown, there may be an N3 interface between the NG-RAN and the user plane function (UPF) of the user plane protocol architecture 400, and there may be an N6 interface between the UPF and the core network (CNW).

[0064] As further shown, the remote UE and the relay UE can be associated with the corresponding PC5 protocol stacks 315 / 320 and 415 / 420, so that communication can be performed on the PC5 interface between the remote UE and the relay UE. The PC5 protocol stack may include a PC5 radio link control (RLC) component, a PC5 medium access control (MAC) component, a PC5 physical (PHY) component, etc. The communication between the remote UE and the relay UE using the PC5 interface may be referred to as side link communication. The corresponding PC5 protocol stack may be associated with one or more of a PC5-S entity, a PC5-radio resource control (RRC) entity, or a PC5-PDCP entity, as shown in reference numeral 325. The PC5-S entity may manage a side link signaling interface, such as a PC5-S interface. A UE including a PC5-S entity and / or a PC5-RRC entity may manipulate control signaling and configuration of a side link connection (such as a connection for relaying between a remote UE and a relay UE) with another UE. In some aspects, the PC5 protocol stack 315 / 320 and 415 / 420 may not include a PC5-S entity or a PC5-RRC entity. In this case, the NG-RAN may handle the control signaling and configuration of the side link connection. A layer 2 relay service using a UE with a PC5-S / PC5-RRC entity may be referred to as an L2' (e.g., L2-primary) relay service, while a layer 2 relay service using a UE without a PC5-S / PC5-RRC entity may be referred to as an L2 relay service.

[0065] like Figure 3 As shown in the reference numeral 330, the remote UE is associated with a non-access stratum (NAS) stack, which includes a NAS session management (NAS-SM) component, a NAS session management (NAS-SM) component, and one or more radio access components (e.g., an NR-RRC component and an NR-PDCP component). Figure 3As shown by reference numeral 335, the relay UE is associated with a radio access stack, which includes an NR-RLC component, an NR-MAC component, and an NR-PHY component. In addition, the NG-RAN is associated with a radio access interface stack shown by reference numeral 340, which includes an NR-RLC component, an NR-MAC component, an NR-PHY component, an NR-RRC entity, and an NR-PDCP entity.

[0066] The adaptation layer entity of the relay UE shown by reference numeral 345 can manipulate the relay from the remote UE to the network or from the network to the remote UE. As used herein, "network" may refer to any one or more of NG-RAN, AMF, SMF, UPF, or core network (CNW). In some aspects, the adaptation layer is referred to as an adaptation layer entity. In some aspects, the adaptation layer entity may be a separate entity between the radio link control entity and the packet data convergence entity. In some aspects, the adaptation layer entity may be logically part of the packet data convergence entity or the radio link control entity.

[0067] Communication between the stacks of the remote UE is indicated by the lines shown in the reference numeral 350. The lines between the NR-PDCP entity and the PC5-RLC entity indicate how messages (e.g., NR RRC messages generated by the radio access protocol stack) that are not encapsulated in a sidelink signaling container (such as a PC5-S container) can be transmitted from the radio access stack to the PC5 stack for transmission via the sidelink interface, or how messages that are not encapsulated in a PC5-S container can be transmitted from the PC5 stack to the radio access stack after being received via the sidelink interface. Note that the lines between the NR-PDCP entity and the PC5-RLC entity do not involve the PC5-S or PC5-PDCP entities, meaning that the PC5-S and PC5-PDCP entities do not process such messages. Similar lines are shown to indicate communication between the adaptation layer and the PC5-RLC entity, which bypasses the PC5-S and PC5-PDCP entities of the relay UE.

[0068] The line between the NR-PDCP entity and the PC5-S or PC5-RRC entity indicates how a message encapsulated in a PC5-S container (e.g., an NR RRC message generated by the radio access protocol stack) can be transferred from the radio access stack to the PC5 stack for transmission via the side link interface, or how a message encapsulated in a PC5-S container can be transferred from the PC5 stack to the radio access stack after being received via the side link interface. Note that the line between the NR-PDCP entity and the PC5-RLC entity involves the PC5-S entity, which means that the PC5-S entity can manipulate such messages.

[0069] like Figure 4As shown by reference numeral 425, the remote UE is associated with a user plane protocol stack, which may include an application (APP) component, a protocol data unit (PDU) component, an NR-SDAP component, and an NR-PDCP component. In addition, the NG-RAN is associated with a user plane component shown by reference numeral 430, which includes an NR-SDAP component and an NR-PDCP component. The NR-SDAP component and the NR-PDCP component may be referred to as a radio access entity in this document.

[0070] NR user plane traffic (indicated by the line indicated by "NR UP") may be transmitted between the NR-PDCP entity and the PC5-RLC component, as indicated by reference numeral 435. Such NR user plane traffic may be transmitted to the relay UE via one or more bearers, such as an established data radio bearer (DRB) or signaling radio bearer (SRB). As indicated by reference numeral 440, the NR user plane traffic may be provided from the PC5 stack of the relay UE to the adaptation component, and from the adaptation component to the radio access stack of the relay UE. The radio access stack of the relay UE may provide the NR user plane traffic to the NG-RAN (not shown). As indicated by reference numeral 445, sidelink communications, such as PC5 control messaging, may occur between the remote UE and the PC5-SDAP component of the relay UE.

[0071] As pointed out above, Figure 3 and Figure 4 are provided as examples. Other examples can be found in the Figure 3 and Figure 4 Different than described.

[0072] Figure 5 is a diagram of an example 500 of a first discovery model for a UE performing sidelink communication according to the present disclosure. The first discovery model may be referred to as model A. In the first discovery model, a first UE (e.g., UE-1 or an announcing UE) may send an announcement message shown by reference numeral 510. As shown by reference numeral 520, the announcement message may indicate one or more relay types (e.g., L2 relay, L2' relay, layer 3 relay, etc.) that the first UE can perform. For example, the announcement message may include a flag or field indicating one or more relay types. One or more second UEs (e.g., UE-2 to UE-5, or a monitoring UE) may monitor for the announcement message. For the purposes described herein, the announcing UE may be a relay UE, and the monitoring UE may be a remote UE.

[0073] As noted above, the figures are provided as examples. Other examples may differ from what is described with respect to the figures.

[0074] Figure 6 6 is a diagram illustrating an example 600 of a second discovery model for a UE performing sidelink communication according to the present disclosure. The second discovery model may be referred to as model B. As shown, example 600 includes a discoverer UE (e.g., UE-1) and a target UE set (e.g., UE-2 to UE-5).

[0075] As shown in reference numeral 610, the discoverer UE may send a request message. As further shown, the request message may indicate one or more relay types (e.g., L2 relay, L2' relay, layer 3 relay, etc.) that the discoverer UE can perform or expect to use. For example, the request message may include a flag or field indicating one or more relay types. As shown in reference numeral 620, the target UE that receives the request message may provide a response message indicating one or more relay types supported by the target UE. In some aspects, if the target UE receives the request message and supports the relay type indicated by the request message, the target UE may respond. For the purposes described herein, the discoverer UE may be a remote UE, and the target UE may be a potential relay UE for the remote UE.

[0076] As pointed out above, Figure 6 are provided as examples. Other examples can be found in the Figure 6 Different than described.

[0077] A UE (referred to herein as a relay user equipment or relay UE) can relay communications from another UE (referred to herein as a remote user equipment or remote UE) to a network or from a network to a remote UE. In some aspects, a relay UE can perform layer 2UE to network relay, in which an adaptation layer in a layer 2 stack of the relay UE performs forwarding of communications to the remote UE, compared to layer 3 relaying that may occur in the Internet Protocol (IP) layer. Communications between a relay UE and a remote UE may be referred to herein as sidelink communications. In some layer 2UE to network relay applications, a packet data convergence protocol (PDCP) end-to-end connection may be used to transparently transmit non-access stratum (NAS) and RRC messages between a remote UE and a network.

[0078] The ProSe sidelink (PC5) interface may provide a sidelink interface between UEs. For example, a vehicle-to-anything (V2X) communication according to NR Release 16 may be performed using a PC5 unicast control plane stack, which may include a PC5 signaling (PC5-S) interface and a PC5 access layer (AS) (PC5-AS) interface, such as a PC5-RRC interface. A UE communicating using the PC5 interface may use the PC5-S interface and the PC5-RRC interface to configure a unicast link context and exchange AS information. The UE may be associated with a PC5 user plane stack, which may include, for example, a PC5-Service Data Adaptation Protocol (SDAP) entity, a PC5-PDCP entity, etc. The L2' relay service may use the corresponding PC5-S / PC5-RRC entities of the remote UE and the relay UE to perform link establishment and AS configuration for the PC5 interface, while the L2 relay service may use the link and AS configuration configured by the NG-RAN (e.g., via the NR-RRC interface). Figure 3 and Figure 4 The user plane and control plane architecture associated with L2 and L2' relay services are described in more detail.

[0079] The configuration of a communication link between a remote UE and a relay UE for an L2' relay service may involve certain information exchanges between the relay UE and the remote UE in order to configure an SRB for the L2' relay service, such as bearer information, relay information, AS configuration, etc. However, some communication protocols for PC5 unicast link establishment and modification may not provide such information exchanges. In addition, in some cases, it may not be expected that the relay UE provides an L2' relay service. For example, the relay UE may be associated with a bandwidth-limited situation, poor coverage, low battery, etc. As another example, a user of the relay UE may have chosen to opt out of providing relay services. Therefore, providing relay services indiscriminately may be detrimental to the performance of the relay UE or the user experience of the relay UE.

[0080] Some techniques and apparatus described herein provide signaling for unicast link establishment or modification to facilitate L2' relay services. For example, some techniques and apparatus described herein provide for a remote UE to request an L2' relay service from a relay UE. The request may indicate a relay service code associated with the L2' relay service. The relay UE may selectively accept or reject the L2' relay service request based at least in part on the relay service code. In some aspects, the relay UE may indicate support for the L2' relay service to the NG-RAN, and the NG-RAN may provide a relay configuration for the L2' relay service. The relay UE may provide at least a portion of the relay configuration to the remote UE. The remote UE and the relay UE may configure SRBs and / or unicast links for the L2' relay service based on the relay configuration. In this way, configuration of SRBs on unicast links for the L2' relay service is enabled. Furthermore, the relay UE may selectively accept or reject the L2' relay service based at least in part on the relay service code, thereby improving the performance and resource utilization of the relay UE in situations where the performance or resource utilization of the relay UE would be negatively impacted by the L2' relay service.

[0081] Figure 7 700 is a diagram illustrating an example of registration and establishment of a sidelink connection of a UE for performing sidelink communication according to the present disclosure. As shown, example 700 includes a remote UE (e.g., UE 120), a relay UE (e.g., UE 120), an NG-RAN, an AMF, an SMF, and a UPF. One or more of the AMF, SMF, UPF, NG-RAN, or a base station (e.g., BS 110) may be referred to as a network entity.

[0082] As shown in reference numeral 705, the remote UE and the relay UE may perform 5G system (5GS) registration with respect to the 5G network. For example, the 5GS registration may include ProSe service authorization and policy provision for sidelink communication between the remote UE and the relay UE.

[0083] As shown in reference numeral 710, the remote UE and the relay UE may perform a discovery process to discover each other. For example, the remote UE and the relay UE may perform a combined Figure 5 and Figure 6 Thus, the remote UE and the relay UE may determine that the remote UE has requested the L2' relay service. For example, the relay UE may determine that the remote UE has requested the L2' relay service based at least in part on the combination of Figure 5 and Figure 6The announcement message or appeal message described herein determines that the remote UE has requested the L2' relay service. In some aspects, the relay UE may determine that the remote UE has requested the L2' relay service based at least in part on the reserved relay service code associated with the L2' relay. For example, the relay service code may indicate the type of L2 relay service that the remote UE expects to utilize. If the relay service code has a specific value or is within a specific range, the relay UE may determine that the L2 relay service is an L2' relay service. In some aspects, one or more bits (e.g., one or more first bits) of the relay service code may indicate which type of UE to NW relay service is supported. For example, a first bit value (e.g., 00) may indicate an L3 relay, a second bit value (e.g., 01) may indicate an L2' relay, and a third bit value (e.g., 10) may indicate both L2' and L3 relays. In some aspects, the relay service code may indicate support for L3 relays, L2' relays, or both via a field or flag value received during the policy provision of the corresponding UE.

[0084] As indicated by reference numeral 715, the remote UE and the relay UE may establish a unicast link for relaying. For example, the remote UE and the relay UE may establish a one-to-one PC5 communication session involving authorization and authentication of the remote UE. If the remote UE and the relay UE support L2' relay services, the remote UE and the relay UE may configure the session using the respective PC5-S / PC5-RRC interfaces of the remote UE and the relay UE. As further shown, the unicast link establishment may include a request for L2' relay support. This may indicate that the one-to-one PC5 communication session will be used for L2' relaying. Thus, the remote UE and the relay UE may configure a unicast link for L2' relaying, as shown in conjunction with Figure 8 and Fig. 9 Described in more detail.

[0085] As indicated by reference numeral 720, the remote UE and the relay UE may perform RRC connection / AS security context establishment with the NG-RAN and / or AMF. As indicated by reference numeral 725, the remote UE and the relay UE may perform NAS connection / NAS security context establishment with the NG-RAN and / or AMF. As indicated by reference numeral 730, the remote UE and the relay UE may perform PDU session establishment or modification for the remote UE. Thereafter, the remote UE and the relay UE may communicate the relayed services with the UPF.

[0086] As pointed out above, Figure 7 are provided as examples. Other examples can be found in the Figure 7 Different than described.

[0087] Figure 8is a diagram illustrating an example 800 of a configuration of a layer 2 relay service on a sidelink associated with a connection establishment according to the present disclosure. As shown, the example 800 includes a relay UE, a remote UE, and a NG-RAN.

[0088] like Figure 8 And as shown by reference numeral 805, the remote UE and the relay UE may perform L2 relay discovery. For example, the remote UE and the relay UE may perform Figure 5 , Figure 6 and Figure 7 One or more operations described. Thus, the remote UE may identify the relay UE as a potential relay UE for the L2' relay service. In some aspects, the remote UE may perform L2 relay discovery based at least in part on initiating an application associated with a particular service. For example, the remote UE may determine to request the L2' relay service based at least in part on the application initiation, and may perform L2 relay discovery accordingly to identify a relay UE that can provide the L2' relay service.

[0089] As shown in the figure numeral 810, the remote UE may provide a direct communication request to the relay UE. As further shown, the direct communication request may include an L2' relay request, also referred to herein as a request for a layer 2 relay service. In other words, the request for a layer 2 relay service should be understood as a request for an L2' relay service. As further shown, the direct communication request may include a relay service code. The relay service code may identify the relay type of the L2' relay service. For example, the relay service code may identify the L2' relay service as an emergency service, a gaming service, a low-latency service, or another type of service. In some aspects, the direct communication request may be included in another message (such as Figure 8 The L2' relay request and / or relay service code is provided in the direct security mode completion message shown in FIG.

[0090] As indicated by reference numeral 815, in some aspects, the relay UE may provide an indication to the NG-RAN that the relay UE supports the L2' relay service. For example, the relay UE may provide the indication in a sidelink UE information, etc. Thus, the relay UE may use a sidelink UE information message to indicate the need for L2' relay operation. In some aspects, the relay UE may provide the indication when initiating an L2' relay service announcement to obtain a relay configuration. In this case, the relay UE may store the relay configuration and may provide at least a portion of the relay configuration to one or more remote UEs connected for the L2' relay service. In some aspects, the relay UE may provide the information during unicast link establishment, such as Figure 8 For example, the relay UE may provide the information when establishing a unicast link with the remote UE, when establishing a unicast link with each remote UE, and the like.

[0091] As shown in the reference numeral 820, the relay UE may provide information indicating whether the relay UE accepts or rejects the L2' relay service to the remote UE. For example, the relay UE may determine whether to accept or reject the L2' relay service based at least in part on the relay service code associated with the L2' relay service. The relay UE may provide information indicating whether the relay UE accepts or rejects the L2' relay service in a direct communication acceptance message (indicating that the relay UE accepts the L2' relay service) or a direct communication rejection message (indicating that the relay UE rejects the L2' relay service). In some aspects, the direct communication rejection message may indicate that the relay UE rejects the L2' relay service based at least in part on a cause value. For example, the cause value may indicate that the specified L2' relay service cannot be supported or is not supported. In some aspects, after exchanging a direct security mode command message and / or a direct security mode completion message between the relay UE and the remote UE (e.g., after security establishment for a unicast link is completed), the relay UE may provide information indicating whether the relay UE accepts or rejects the L2' relay service.

[0092] In some aspects, acceptance of certain types of L2' relay services by the relay UE may be required. For example, the relay UE may not be allowed to reject emergency service L2' relay services. Thus, the likelihood of successful L2' relay service configuration for emergency services is increased.

[0093] As shown in the reference numeral 825, the NG-RAN may provide a relay configuration to the remote UE. For example, the NG-RAN may provide the relay configuration in an RRC reconfiguration message, etc. In some aspects, the relay configuration may identify a signaling radio bearer (SRB) configuration, such as a remote UE Uu SRB configuration. For example, the remote UE may communicate with the NG-RAN via the relay UE using the Uu interface SRB. The remote UE Uu SRB configuration may identify the configuration of the NR-PDCP entity of the remote UE to be used for the Uu interface SRB. In some aspects, the relay configuration may identify a PC5 AS configuration for a PC5-RLC entity of a remote UE and / or a relay UE, a PC5-MAC entity of a remote UE and / or a relay UE, a PC5-PHY entity of a remote UE and / or a relay UE, etc. In some aspects, the relay configuration may identify a Uu AS configuration for an RLC entity of a relay UE, a MAC entity of a remote UE and / or a relay UE, a PHY entity of a remote UE and / or a relay UE, etc. In some aspects, the relay configuration may identify an adaptation layer configuration for an adaptation layer of a relay UE.

[0094] In some aspects, the remote UE and / or the relay UE may be configured with a relay configuration. For example, the remote UE and / or the relay UE may be pre-configured with the relay configuration. In some aspects, the configuration may occur during pre-configuration of the remote UE and / or the relay UE. In some aspects, the relay configuration may be specified in a standard such as a wireless telecommunications standard (e.g., a 3GPP technical specification). In some aspects, a signaling radio bearer 0 (SRB0, which handles RRC signaling) and corresponding logical channels for the remote UE may be configured on the PC5 and Uu links. Additionally or alternatively, one or more other SRBs on the remote UE may be pre-configured for the L2' relay service.

[0095] In some aspects, the messages shown by reference numerals 815 and 825 may be provided simultaneously with one or more messages in the rectangle shown by reference numeral 830. For example, the messages shown by reference numerals 815 and 825 may be sent in parallel with one or more of the messages shown by reference numerals 820, 835, etc.

[0096] As shown in reference numeral 840, the relay UE may provide at least a portion of the relay configuration to the remote UE. For example, the relay UE may provide the remote UE Uu SRB configuration, PC5 AS configuration, etc. As shown, the relay UE may provide the relay configuration in an RRC reconfiguration message (such as an RRC reconfiguration sidelink message). For example, the relay UE may reconfigure the remote UE with the relay configuration. Thus, the relay UE may configure the PC5 unicast link with one or more SRBs to be used by the remote UE for the L2' relay service.

[0097] As indicated by reference numerals 845 and 850, the remote UE and the relay UE may communicate with the NG-RAN based at least in part on the relay configuration. For example, as indicated by reference numeral 845, the remote UE may provide NR Uu interface control plane data over a PC5 unicast link between the remote relay and the relay UE. The adaptation layer of the relay UE may route SRB traffic received from the remote UE to an appropriate Uu logical channel for communication with the NG-RAN based at least in part on the relay configuration and / or one or more SRBs associated with the SRB traffic. As indicated by reference numeral 850, the relay UE may relay traffic to and / or from the NG-RAN using one or more Uu relay logical channels (LCHs), which may be identified by the relay configuration or configured by the NG-RAN.

[0098] As pointed out above, Figure 8 are provided as examples. Other examples can be found in the Figure 8 Different than described.

[0099] Fig. 91 is a diagram illustrating an example 900 of a configuration of a layer 2 relay service on a side link associated with a connection modification according to the present disclosure. As shown, the example 900 includes a relay UE (e.g., UE 120), a remote UE (e.g., UE 120), and an NG-RAN. As indicated by reference numeral 905, the example 900 is a diagram in which (e.g., using Figure 7 The operation described above is a situation in which a unicast link is established between the remote UE and the relay UE and communication is ongoing between the remote UE and the relay UE on the unicast link.

[0100] As shown at 910, the remote UE and the relay UE may perform L2′ relay service discovery, such as in conjunction with Figure 5 and Figure 6 For example, the remote UE may determine that the relay UE associated with the PC5 unicast link supports L2' relay service.

[0101] As indicated by reference numeral 915, the remote UE may provide a link modification request to the relay UE. As further shown, the link modification request may include an L2' relay request and a relay service code corresponding to the L2' relay request. In some aspects, as indicated by reference numeral 920, the relay UE may provide information indicating L2' relay support to the NG-RAN, such as in conjunction with Figure 8 As shown in reference numeral 925, the NG-RAN may provide a relay configuration to the relay UE based at least in part on the information indicating L2' relay support, which is also combined with Figure 8 As shown in more detail in the figure 930, the relay UE may configure the remote UE based at least in part on the relay configuration (e.g., one or more SRBs to be used for the unicast link for the L2' relay service may be configured). As further shown, the relay UE and the remote UE may communicate via PC5 unicast, and the relay UE may communicate with the NG-RAN using one or more Uu relay logical channels. Therefore, the relay UE and the remote UE may configure an existing connection for the L2' relay service via the relay UE without removing or releasing the existing connection, thereby improving the configuration efficiency of the L2' relay service.

[0102] Fig.10 is a diagram illustrating an example process 1000 performed, for example, by a UE, according to the present disclosure. Example process 1000 is an example of a remote UE (eg, UE 120, remote UE 305, remote UE 405, etc.) performing operations associated with a layer 2 relay unicast link establishment.

[0103] like Fig.10As shown in , in some aspects, process 1000 may include sending a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service to a relay UE (block 1010). For example, a remote UE (e.g., using controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, etc.) may send a request for a layer 2 relay service (e.g., L2' relay service) and a relay service code associated with the layer 2 relay service to a relay UE as described above.

[0104] like Fig.10 As further shown in FIG. 1 , in some aspects, process 1000 may include receiving a message from the relay UE indicating that the relay UE accepts the layer 2 relay service associated with the relay service code (block 1020). For example, the UE (e.g., using antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, controller / processor 280, etc.) may receive a message from the relay UE indicating that the relay UE accepts the layer 2 relay service associated with the relay service code as described above.

[0105] like Fig.10 As further shown in FIG. 1 , in some aspects, process 1000 may include establishing a radio access SRB for a layer 2 relay service using a remote UE radio access SRB configuration (block 1030). For example, a UE (e.g., using controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, etc.) may establish a radio access SRB for a layer 2 relay service using a remote UE radio access SRB configuration as described above.

[0106] like Fig.10 As further shown in FIG. 1 , in some aspects, process 1000 may include communicating via a radio access SRB (block 1040). For example, a UE (e.g., using controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, etc.) may communicate via a radio access SRB as described above.

[0107] Process 1000 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in combination with one or more other processes described elsewhere herein.

[0108] In a first aspect, a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service are provided in a direct communication request message.

[0109] In a second aspect, alone or in combination with the first aspect, a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service are provided in a direct security mode complete message.

[0110] In a third aspect, alone or in combination with one or more of the first and second aspects, the relay service code indicates that the layer 2 relay service is associated with an emergency service.

[0111] In a fourth aspect, alone or in combination with one or more of the first to third aspects, the process 1000 includes receiving a remote UE radio access SRB configuration from a relay UE.

[0112] In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, the remote UE radio access SRB configuration is received in a sidelink radio resource control reconfiguration message.

[0113] In a sixth aspect, alone or in combination with one or more of the first to fifth aspects, a remote UE radio access SRB configuration is received together with information indicating a sidelink access layer configuration for a sidelink between the relay UE and the remote UE.

[0114] In a seventh aspect, alone or in combination with one or more of the first to sixth aspects, prior to sending a request for a layer 2 relay service, the remote UE is configured with a remote UE radio access SRB configuration and a sidelink access layer configuration.

[0115] In the eighth aspect, alone or in combination with one or more aspects of the first to seventh aspects, a link modification request message is used to provide a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service, at least in part based on the remote UE and the relay UE having a unicast side link.

[0116] In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, communication via a radio access SRB is performed without encapsulating traffic through sidelink signaling or a radio resource configuration entity.

[0117] although Fig.10 Example blocks of process 1000 are shown, but in some aspects, process 1000 may include Fig.10 Additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in the process 1000. Additionally or alternatively, two or more blocks of the blocks of process 1000 may be performed in parallel.

[0118] Fig.11FIG. 1 is a diagram illustrating an example process 1100 performed, for example, by a UE according to the present disclosure. Example process 1100 is an example in which a relay UE (eg, UE 120, relay UE 310, relay UE 410, etc.) performs operations associated with a layer 2 relay unicast link establishment.

[0119] like Fig.11 As shown, in some aspects, process 1100 may include receiving a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service from a remote UE (block 1110). For example, a relay UE (e.g., using antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, controller / processor 280, etc.) may receive a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service from a remote UE as described above.

[0120] like Fig.11 As further shown in FIG. 1 , in some aspects, process 1100 may include providing a message to the remote UE indicating whether the relay UE accepts the layer 2 relay service based at least in part on the relay service code (block 1120). For example, the relay UE (e.g., using the controller / processor 280, the transmit processor 264, the TX MIMO processor 266, the MOD 254, the antenna 252, etc.) may provide a message to the remote UE indicating whether the relay UE accepts the layer 2 relay service based at least in part on the relay service code as described above.

[0121] like Fig.11 As further shown in FIG. 1 , in some aspects, process 1100 may include establishing a radio access SRB for a layer 2 relay service with a remote UE using a remote UE radio access SRB configuration when the relay UE accepts the layer 2 relay service associated with the relay service code (block 1130). For example, the relay UE (e.g., using the controller / processor 280, the transmit processor 264, the TX MIMO processor 266, the MOD 254, the antenna 252, etc.) may establish a radio access SRB for a layer 2 relay service with a remote UE using a remote UE radio access SRB configuration when the relay UE accepts the layer 2 relay service associated with the relay service code as described above.

[0122] Process 1100 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in combination with one or more other processes described elsewhere herein.

[0123] In a first aspect, a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service are received in a direct communication request message.

[0124] In a second aspect, alone or in combination with the first aspect, a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service are received in a direct security mode complete message.

[0125] In a third aspect, alone or in combination with one or more of the first and second aspects, the layer 2 relay service cannot be denied when the relay service code indicates that the layer 2 relay service is associated with an emergency service.

[0126] In a fourth aspect, alone or in combination with one or more of the first to third aspects, the process 1100 includes providing a remote UE radio access SRB configuration to a remote UE.

[0127] In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, the remote UE radio access SRB configuration is provided in a sidelink radio resource control reconfiguration message.

[0128] In a sixth aspect, alone or in combination with one or more of the first to fifth aspects, the relay UE is pre-configured with information indicating a sidelink access stratum configuration for a sidelink between the relay UE and the remote UE.

[0129] In a seventh aspect, alone or in combination with one or more of the first to sixth aspects, the process 1100 includes providing an indication to a base station that the relay UE supports layer 2 relay services; and receiving a relay configuration from the base station based at least in part on the indication.

[0130] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, the indication is provided in a sidelink UE information message.

[0131] In the ninth aspect, alone or in combination with one or more aspects from the first to the eighth aspects, the relay configuration includes at least one of the following: a remote UE radio access SRB configuration, information indicating a sidelink access layer configuration for a sidelink between the relay UE and the remote UE, a radio access layer configuration for a radio access link between the relay UE and the base station, or an adaptation layer configuration for processing a remote UE.

[0132] In a tenth aspect, alone or in combination with one or more of the first to ninth aspects, the indication that the relay UE supports the layer 2 relay service is provided after receiving a request for the layer 2 relay service.

[0133] In an eleventh aspect, alone or in combination with one or more of the first to tenth aspects, the indication that the relay UE supports the layer 2 relay service is provided simultaneously with a message indicating whether the relay UE accepts the layer 2 relay service.

[0134] In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, the indication that the relay UE supports layer 2 relay service is provided simultaneously with the notification of the layer 2 relay service capability of the relay UE.

[0135] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, the indication that the relay UE supports layer 2 relay services is provided before the remote UE connects to the relay UE.

[0136] In a fourteenth aspect, alone or in combination with one or more of the first to thirteenth aspects, the indication that the relay UE supports layer 2 relay services is provided during unicast link establishment to the remote UE.

[0137] In the fifteenth aspect, alone or in combination with one or more aspects of the first to fourteenth aspects, a link modification request message is used to receive a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service, at least in part based on the remote UE and the relay UE having a unicast side link.

[0138] although Fig.11 Example blocks of process 1100 are shown, but in some aspects, process 1100 may include Fig.11 Additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in the process 1100. Additionally or alternatively, two or more blocks of the blocks of process 1100 can be performed in parallel.

[0139] Fig.12 1 is a diagram illustrating an example process 1200 performed, for example, by a base station according to the present disclosure. The example process 1200 is one in which a base station (e.g., Figure 3-Figure 9 An example of BS 110, NG-RAN, SMF, UPF or AMF, etc.) performing operations associated with Layer 2 relay unicast link establishment.

[0140] like Fig.12 As shown, in some aspects, process 1200 may include receiving an indication from a relay UE that the relay UE supports layer 2 relay services (block 1210). For example, a base station (e.g., using antenna 234, DEMOD 232, MIMO detector 236, receive processor 238, controller / processor 240, etc.) may receive an indication from a relay UE that the relay UE supports layer 2 relay services as described above.

[0141] like Fig.12As further shown in FIG. 1 , in some aspects, process 1200 may include sending a relay configuration to the relay UE based at least in part on the indication (block 1220). For example, the base station (e.g., using controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna 234, etc.) may send the relay configuration to the relay UE based at least in part on the indication as described above.

[0142] like Fig.12 As further shown in FIG. 1 , in some aspects, process 1200 may include communicating with a remote UE via a relay UE based at least in part on the relay configuration (block 1230). For example, a base station (e.g., using controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna 234, etc.) may communicate with a remote UE via a relay UE based at least in part on the relay configuration as described above.

[0143] Process 1200 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in combination with one or more other processes described elsewhere herein.

[0144] In a first aspect, the indication is received in a SIDELINK UE INFORMATION message.

[0145] In a second aspect, alone or in combination with the first aspect, the relay configuration comprises at least one of: a remote UE radio access SRB configuration, information indicating a side link access layer configuration for a side link between the relay UE and the remote UE, a radio access layer configuration for a radio access link between the relay UE and the base station, or an adaptation layer configuration for processing a remote UE.

[0146] In a third aspect, alone or in combination with one or more of the first and second aspects, the indication that the relay UE supports layer 2 relay service is received simultaneously with the notification of the layer 2 relay service capability of the relay UE.

[0147] In a fourth aspect, alone or in combination with one or more of the first to third aspects, the indication that the relay UE supports layer 2 relay services is received before the remote UE connects to the relay UE.

[0148] In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, the indication that the relay UE supports layer 2 relay services is received during unicast link establishment or link modification to the remote UE.

[0149] although Fig.12 Example blocks of process 1200 are shown, but in some aspects, process 1200 may include Fig.12Additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in the process 1200. Additionally or alternatively, two or more blocks of the blocks of process 1200 can be performed in parallel.

[0150] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the various aspects.

[0151] The following provides an overview of some aspects of the disclosure:

[0152] Aspect 1: A method of wireless communication performed by a remote user equipment (UE), comprising: sending a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service to a relay UE; receiving a message from the relay UE indicating that the relay UE accepts the layer 2 relay service associated with the relay service code; establishing a radio access signaling radio bearer (SRB) for the layer 2 relay service using a remote UE radio access signaling radio bearer (SRB) configuration; and communicating via the radio access SRB.

[0153] Aspect 2: The method as described in aspect 1, wherein a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service are provided in the direct communication request message.

[0154] Aspect 3: The method of aspect 1, wherein the request for the layer 2 relay service and the relay service code associated with the layer 2 relay service are provided in the direct security mode complete message.

[0155] Aspect 4: The method according to any one of aspects 1 to 3, wherein the relay service code indicates that the layer 2 relay service is associated with an emergency service.

[0156] Aspect 5: The method according to any one of aspects 1-4, further comprising: receiving a remote UE radio access SRB configuration from a relay UE.

[0157] Aspect 6: The method of aspect 5, wherein the remote UE radio access SRB configuration is received in a sidelink radio resource control reconfiguration message.

[0158] Aspect 7: The method of aspect 5, wherein the remote UE radio access SRB configuration is received together with information indicating a sidelink access layer configuration for a sidelink between the relay UE and the remote UE.

[0159] Aspect 8: The method according to any one of aspects 1-7, wherein before sending the request for the layer 2 relay service, the remote UE is configured with a remote UE radio access SRB configuration and a sidelink access layer configuration.

[0160] Aspect 9: A method as described in any one of Aspects 1-8, wherein, based at least in part on the remote UE and the relay UE having a unicast side link, a link modification request message is used to provide a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service.

[0161] Aspect 10: The method according to any one of aspects 1 to 9, wherein the communication via the radio access SRB is performed without encapsulating the traffic through sidelink signaling or a radio resource configuration entity.

[0162] Aspect 11: A method of wireless communication performed by a relay user equipment (UE), comprising: receiving a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service from a remote UE; providing a message to the remote UE indicating whether the relay UE accepts the layer 2 relay service based at least in part on the relay service code; and when the relay UE accepts the layer 2 relay service associated with the relay service code, establishing a radio access signaling radio bearer (SRB) for the layer 2 relay service with the remote UE using a remote UE radio access signaling radio bearer (SRB) configuration.

[0163] Aspect 12: The method of aspect 11, wherein when the relay service code indicates that the layer 2 relay service is associated with an emergency service, the layer 2 relay service cannot be rejected.

[0164] Aspect 13: The method according to any one of aspects 11-12 further comprises: providing a remote UE radio access SRB configuration to the remote UE.

[0165] Aspect 14: The method of aspect 13, wherein the remote UE radio access SRB configuration is provided in a sidelink radio resource control reconfiguration message.

[0166] Aspect 15: The method of aspect 13, wherein the relay UE is pre-configured with information indicating a sidelink access stratum configuration for a sidelink between the relay UE and the remote UE.

[0167] Aspect 16: The method as described in any one of aspects 11-15 also includes: providing an indication to the base station that the relay UE supports layer 2 relay service; and receiving a relay configuration from the base station based at least in part on the indication.

[0168] Aspect 17: A method as described in Aspect 16, wherein the relay configuration includes at least one of the following: a remote UE radio access SRB configuration, information indicating a side link access layer configuration for a side link between the relay UE and the remote UE, a radio access layer configuration for a radio access link between the relay UE and the base station, or an adaptation layer configuration for processing a remote UE.

[0169] Aspect 18: The method of aspect 16, wherein the indication that the relay UE supports the layer 2 relay service is provided after receiving a request for the layer 2 relay service.

[0170] Aspect 19: The method according to aspect 16, wherein the indication that the relay UE supports the layer 2 relay service is provided simultaneously with a message indicating whether the relay UE accepts the layer 2 relay service.

[0171] Aspect 20: The method according to aspect 16, wherein the indication that the relay UE supports the layer 2 relay service is provided simultaneously with the notification of the layer 2 relay service capability of the relay UE.

[0172] Aspect 21: The method of aspect 16, wherein the indication that the relay UE supports layer 2 relay service is provided before the remote UE connects to the relay UE.

[0173] Aspect 22: The method of aspect 16, wherein the indication that the relay UE supports layer 2 relay service is provided during unicast link establishment for the remote UE.

[0174] Aspect 23: A method as described in any one of Aspects 11-22, wherein, based at least in part on the remote UE and the relay UE having a unicast side link, a link modification request message is used to receive a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service.

[0175] Aspect 24: A method of wireless communication performed by a base station, comprising: receiving an indication from a relay user equipment (UE) that the relay UE supports layer 2 relay services; sending a relay configuration to the relay UE based at least in part on the indication; and communicating with a remote UE via the relay UE based at least in part on the relay configuration.

[0176] Aspect 25: A method as described in Aspect 24, wherein the indication is received in a sidelink UE information message.

[0177] Aspect 26: A method as described in any one of Aspects 24-25, wherein the relay configuration includes at least one of the following: a remote UE radio access signaling radio bearer (SRB) configuration, information indicating a side link access layer configuration for a side link between the relay UE and the remote UE, a radio access layer configuration for a radio access link between the relay UE and the base station, or an adaptation layer configuration for processing a remote UE.

[0178] Aspect 27: The method according to any one of aspects 24 to 26, wherein the indication that the relay UE supports the layer 2 relay service is received simultaneously with the notification of the layer 2 relay service capability of the relay UE.

[0179] Aspect 28: The method according to any one of aspects 24-27, wherein the indication that the relay UE supports the layer 2 relay service is received before the remote UE connects to the relay UE.

[0180] Aspect 29: The method according to any one of aspects 24-28, wherein the indication that the relay UE supports the layer 2 relay service is received during a unicast link establishment or link modification for the remote UE.

[0181] Aspect 30: An apparatus for wireless communication at a device, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method described in one or more of Aspects 1-29.

[0182] Aspect 31: A device for wireless communication, comprising a memory and one or more processors coupled to the memory, wherein the memory and the one or more processors are configured to execute the method described in one or more of Aspects 1-29.

[0183] Aspect 32: An apparatus for wireless communication, comprising at least one component for performing the method of one or more of aspects 1-29.

[0184] Aspect 33: A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform the method of one or more of aspects 1-29.

[0185] Aspect 34: A non-transitory computer-readable medium storing an instruction set for wireless communication, the instruction set comprising one or more instructions that, when executed by one or more processors of a device, cause the device to perform the method of one or more of aspects 1-29.

[0186] As used herein, the term "component" is intended to be broadly interpreted as a combination of hardware and / or hardware and software. "Software" should be broadly interpreted as meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software modules, applications, software applications, software packages, firmware, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether it is described in software, firmware, middleware, microcode, hardware description language or other terms. As used herein, the processor is implemented with hardware and / or a combination of hardware and software. It will be obvious that the system and / or method described herein can be implemented with different forms of hardware and / or a combination of hardware and software. The actual dedicated control hardware or software code for implementing these systems and / or methods does not limit these aspects. Therefore, the operation and behavior of the system and / or method are described herein without reference to specific software codes-it should be understood that software and hardware can be designed to implement the system and / or method based at least in part on the description herein.

[0187] As used herein, satisfying a threshold may refer to a value greater than a threshold, greater than or equal to a threshold, less than a threshold, less than or equal to a threshold, equal to a threshold, not equal to a threshold, etc., depending on the context.

[0188] Although the specific combination of features is described in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features can be combined in a manner that is not specifically recorded in the claims and / or not specifically disclosed in the specification. Although each dependent claim listed below can be directly subordinate to only one claim, the disclosure of various aspects includes that each dependent claim is combined with each other claim in this group of claims. As used herein, the phrase "at least one" referring to the list of items refers to any combination of those items including a single member. As an example, "at least one of a, b or c" is intended to cover a, b, c, ab, ac, bc and abc, and any combination with multiple identical elements (for example, aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc and ccc or any other sorting of a, b and c).

[0189] Unless explicitly described in this way, any element, action or instruction used herein should not be interpreted as critical or necessary. In addition, as used herein, the article "a" and "an" are intended to include one or more projects, and can be used interchangeably with "one or more". In addition, as used herein, the article "the" is intended to include one or more projects related to the article "the", and can be used interchangeably with "one or more". In addition, as used herein, the term "set" and "group" are intended to include one or more projects (for example, related projects, unrelated projects, or a combination of related projects and unrelated projects), and can be used interchangeably with "one or more". In the case of only meaning a project, the phrase "only one" or similar language is used. In addition, as used herein, the term "has", "have", "having" etc. are intended to be open terms. In addition, unless otherwise explicitly stated, the phrase "based on" is intended to represent "based at least in part". Additionally, as used herein, the term "or" when used in a serial form is intended to be inclusive and can be used interchangeably with "and / or" unless expressly stated otherwise (eg, if used in conjunction with "either" or "only one of").

Claims

1. A method of wireless communication performed by a remote user equipment UE, comprising: sending a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service to a relay UE, the relay service code identifying a relay type of the layer 2 relay service; receiving, from the relay UE, a message indicating that the relay UE accepts the layer 2 relay service associated with the relay service code; wherein, when the relay service code indicates that the layer 2 relay service is associated with an emergency service, the message instructs the relay UE to accept the layer 2 relay service, and wherein, when the relay service code indicates that the layer 2 relay service includes a type of layer 2 relay service that is not associated with the emergency service, the message instructs the relay UE to reject the layer 2 relay service; establishing a radio access SRB for the layer 2 relay service using a remote UE radio access signaling radio bearer (SRB) configuration based at least in part on a message indicating that the relay UE accepts the layer 2 relay service associated with the relay service code; wherein the radio access SRB for the layer 2 relay service is established based at least in part on the relay UE providing an indication to a base station that the relay UE supports the layer 2 relay service and receiving a relay configuration based at least in part on the indication from the base station; and The communication is performed via the radio access SRB.

2. The method of claim 1, wherein: The request for the layer 2 relay service and the relay service code associated with the layer 2 relay service are provided in a direct communication request message.

3. The method of claim 1, wherein: The request for the layer 2 relay service and the relay service code associated with the layer 2 relay service are provided in a direct security mode complete message.

4. The method of claim 1, wherein: When the layer 2 relay service is associated with an emergency service, a gaming service, or a low-latency service, the message indicates that the relay UE accepts the layer 2 relay service.

5. The method of claim 1, further comprising: The remote UE radio access SRB configuration is received from the relay UE.

6. The method of claim 5, wherein: The remote UE radio access SRB configuration is received in a sidelink radio resource control reconfiguration message.

7. The method of claim 5, wherein: The remote UE radio access SRB configuration is received together with information indicating a sidelink access layer configuration for a sidelink between the relay UE and the remote UE.

8. The method of claim 1, wherein: Prior to sending the request for the layer 2 relay service, the remote UE is configured with the remote UE radio access SRB configuration and sidelink access layer configuration.

9. The method of claim 1, wherein: Based at least in part on the remote UE and the relay UE having a unicast side link, providing the request for the layer 2 relay service and the relay service code associated with the layer 2 relay service using a link modification request message.

10. The method of claim 1, wherein: Communications via the radio access SRB are performed without encapsulating traffic via sidelink signaling or a radio resource configuration entity.

11. A method of wireless communication performed by a relay user equipment UE, comprising: receiving, from a remote UE, a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service, the relay service code identifying a relay type of the layer 2 relay service; providing a message to the remote UE indicating whether the relay UE accepts the layer 2 relay service based at least in part on the relay service code; wherein, when the relay service code indicates that the layer 2 relay service is associated with an emergency service, the message instructs the relay UE to accept the layer 2 relay service, and wherein, when the relay service code indicates that the layer 2 relay service is not associated with the emergency service, the message instructs the relay UE to reject the layer 2 relay service; providing, to a base station, an indication that the relay UE supports the layer 2 relay service based at least in part on the message indicating that the relay UE accepts the layer 2 relay service associated with the relay service code; receiving, from the base station, a relay configuration based at least in part on the indication; and When the relay UE accepts the layer 2 relay service associated with the relay service code, a radio access SRB for the layer 2 relay service is established with the remote UE using a remote UE radio access signaling radio bearer SRB configuration.

12. The method of claim 11, wherein: When the relay service code indicates that the layer 2 relay service is associated with the emergency service, the layer 2 relay service cannot be denied.

13. The method of claim 11, further comprising: The remote UE radio access SRB configuration is provided to the remote UE.

14. The method of claim 13, wherein: The remote UE radio access SRB configuration is provided in a sidelink radio resource control reconfiguration message.

15. The method of claim 13, wherein: The relay UE is pre-configured with information indicating a sidelink access stratum configuration for a sidelink between the relay UE and the remote UE.

16. The method of claim 11, wherein: The relay configuration includes at least one of the following: the remote UE radio access SRB configuration, information indicating a sidelink access stratum configuration for a sidelink between the relay UE and the remote UE, a radio access stratum configuration for a radio access link between the relay UE and the base station, or Used to process the adaptation layer configuration of the remote UE.

17. The method of claim 11, wherein: The indication that the relay UE supports the layer 2 relay service is provided after receiving the request for the layer 2 relay service.

18. The method of claim 11, wherein: The indication that the relay UE supports the layer 2 relay service is provided simultaneously with the message indicating whether the relay UE accepts the layer 2 relay service.

19. The method of claim 11, wherein: The indication that the relay UE supports the layer 2 relay service is provided simultaneously with announcing the layer 2 relay service capability of the relay UE.

20. The method of claim 11, wherein: The indication that the relay UE supports the layer 2 relay service is provided before the remote UE connects to the relay UE.

21. The method of claim 11, wherein: The indication that the relay UE supports the layer 2 relay service is provided during unicast link establishment to the remote UE.

22. The method of claim 11, wherein: Based at least in part on the remote UE and the relay UE having a unicast side link, the request for the layer 2 relay service and the relay service code associated with the layer 2 relay service are received using a link modification request message.

23. A method of wireless communication performed by a base station, comprising: receiving, from a relay user equipment UE, an indication that the relay UE supports a layer 2 relay service; sending a relay configuration to the relay UE based at least in part on the indication; as well as communicating with a remote UE via the relay UE based at least in part on the relay configuration, wherein the indication is sent by the relay UE based on a relay service code received from a remote UE, and When the relay service code indicates that the layer 2 relay service is associated with an emergency service, the indication indicates that the relay UE accepts the layer 2 relay service and is sent.

24. The method of claim 23, wherein: The indication is received in a SIDELINK UE INFORMATION message.

25. The method of claim 23, wherein: The relay configuration includes at least one of the following: Remote UE Radio Access Signalling Radio Bearer SRB configuration, information indicating a sidelink access stratum configuration for a sidelink between the relay UE and the remote UE, a radio access stratum configuration for a radio access link between the relay UE and the base station, or Used to process the adaptation layer configuration of the remote UE.

26. The method of claim 23, wherein: The indication that the relay UE supports the layer 2 relay service is received simultaneously with the announcement of the layer 2 relay service capability of the relay UE.

27. The method of claim 23, wherein: The indication that the relay UE supports the layer 2 relay service is received before the remote UE connects to the relay UE.

28. The method of claim 23, wherein: The indication that the relay UE supports the layer 2 relay service is received during a unicast link establishment or link modification for the remote UE.

29. A remote user equipment UE for wireless communication, comprising: Memory; as well as one or more processors coupled to the memory, and the one or more processors are configured to: sending a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service to a relay UE, the relay service code identifying a relay type of the layer 2 relay service; receiving, from the relay UE, a message indicating whether the relay UE accepts the layer 2 relay service associated with the relay service code; wherein, when the relay service code indicates that the layer 2 relay service is associated with an emergency service, the message instructs the relay UE to accept the layer 2 relay service, and wherein, when the relay service code indicates that the layer 2 relay service includes a type of layer 2 relay service that is not associated with the emergency service, the message instructs the relay UE to reject the layer 2 relay service; establishing a radio access signaling (SRB) radio bearer (SRB) configuration for the layer 2 relay service using a remote UE radio access signaling (SRB) radio bearer (SRB) configuration based at least in part on the message indicating that the relay UE accepts a layer 2 relay service associated with the relay service code, wherein a radio access SRB for the layer 2 relay service is established based at least in part on the relay UE providing an indication to the base station that the relay UE supports the layer 2 relay service and receiving a relay configuration based at least in part on the indication from the base station; and The communication is performed via the radio access SRB.

30. The remote UE of claim 29, wherein: Communications via the radio access SRB are performed without encapsulation of traffic by sidelink signaling or radio resource configuration entities.

31. A relay user equipment UE for wireless communication, comprising: Memory; as well as one or more processors coupled to the memory, and the one or more processors are configured to: receiving, from a remote UE, a request for a layer 2 relay service and a relay service code associated with the layer 2 relay service, the relay service code identifying a relay type of the layer 2 relay service; providing a message to the remote UE indicating whether the relay UE accepts the layer 2 relay service based at least in part on the relay service code; wherein, when the relay service code indicates that the layer 2 relay service is associated with an emergency service, the message instructs the relay UE to accept the layer 2 relay service, and wherein, when the relay service code indicates that the layer 2 relay service is not associated with the emergency service, the message instructs the relay UE to reject the layer 2 relay service; When the relay UE accepts the layer 2 relay service associated with the relay service code, a radio access SRB for the layer 2 relay service is established with the remote UE using a remote UE radio access signaling radio bearer SRB configuration.

32. The relay UE according to claim 31, wherein: When the relay service code indicates that the layer 2 relay service is associated with the emergency service, the layer 2 relay service cannot be denied.

33. The relay UE according to claim 31, wherein: The one or more processors are further configured to: The remote UE radio access SRB configuration is provided to the remote UE.

34. The relay UE according to claim 33, wherein: The remote UE radio access SRB configuration is provided in a sidelink radio resource control reconfiguration message.

35. The relay UE according to claim 33, wherein: The relay UE is pre-configured with information indicating a sidelink access stratum configuration for a sidelink between the relay UE and the remote UE.

36. The relay UE according to claim 31, wherein: The one or more processors are further configured to: receive, from a base station, a relay configuration based at least in part on an indication that the relay UE accepts the layer 2 relay service, and wherein the relay configuration comprises at least one of: the remote UE radio access SRB configuration, information indicating a sidelink access stratum configuration for a sidelink between the relay UE and the remote UE, a radio access stratum configuration for a radio access link between the relay UE and the base station, or Used to process the adaptation layer configuration of the remote UE.

37. A remote user equipment (UE) for wireless communication, comprising means for performing the method according to any one of claims 1-10.

38. A relay user equipment UE for wireless communication, comprising components for executing the method according to any one of claims 11-22.

39. A non-transitory computer readable medium having stored thereon instructions which, when executed by a processor, cause the processor to perform the method of any one of claims 1-22.

40. A program product comprising instructions which, when executed by a processor, cause the processor to perform the method of any one of claims 1-22.

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