Sidelink assist indication of beam failure

Abstract

Methods, systems, and devices are described for wireless communication at a user equipment (UE). A UE may identify a beam failure for at least one communication beam at the UE. The UE may determine a cause of the beam failure, and may include the cause in a beam failure recovery (BFR) request. The UE may identify a sidelink relay UE to communicate via a sidelink channel and send the BFR request to a network entity. The network entity may receive the BFR request from the sidelink relay UE and identify beam switching parameters based on the type of interference causing the beam failure. The network entity may include the beam switching parameter in a BFR response to the UE. The UE may receive the BFR response and switch to another candidate beam to enable communication with the network entity.

Description

[0001] Cross-reference

[0002] This patent application claims priority to U.S. Patent Application No. 18 / 054,536, entitled "SIDELINK ASSISTED INDICATION OF BEAM FAILURE," filed on November 10, 2022, by Saggar et al., which is assigned to the assignee of the present application and is hereby incorporated by reference in its entirety. Technical Field

[0003] The following relates to wireless communication, including sidelink-assisted indication of beam failure. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasting, and so on. These systems may be capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multi-access systems include fourth-generation (4G) systems (such as Long-Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems) and fifth-generation (5G) systems (which may be referred to as New Radio (NR) systems). These systems may employ techniques such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), or Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing (DFT-S-OFDM).

[0005] A wireless multi-access communication system may include one or more base stations, each supporting wireless communication for communication devices, which may be referred to as User Equipment (UE). In some wireless communication systems, network devices (such as one or more UEs and network entities) may operate in different modes. For example, network devices may operate in full-duplex (FD) mode, half-duplex (HD) mode, and Time Division Duplex (TDD) mode. In some cases, network devices operating in multiple modes may experience multiple types of beam failures. Summary of the Invention

[0006] The described techniques relate to improved methods, systems, devices, and apparatuses for supporting sidelink-assisted indication of beam failures. For example, the described techniques provide for a user equipment (UE) to send a beam failure indication to another UE via a sidelink and an uplink to a network entity. In some wireless communication systems, a UE may identify a beam failure at one or more communication beams at the UE. In some examples, the cause of the beam failure may be due to interference such as self-interference (SI) or cross-link interference (CLI). The UE may use a sidelink with another UE to send a beam failure recovery (BFR) request to the network entity. In some cases, the network entity may receive a BFR request that includes the cause of the beam failure. The network entity may identify one or more beam switching parameters in response to the BFR request and may send a BFR response indicating the beam switching parameters to the UE.

[0007] A method for wireless communication at a UE is described. The method may include: identifying a beam failure of at least one communication beam at the UE; sending, via a sidelink channel, a BFR request to a network entity that includes an indication of whether the beam failure is associated with SI or CLI; and receiving, based on the BFR request, a BFR response indicating one or more beam switching parameters, the BFR request including an indication of whether the beam failure is associated with SI or CLI.

[0008] An apparatus for wireless communication at a UE is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to: identify a beam failure of at least one communication beam at the UE; send, via a sidelink channel, a BFR request to a network entity that includes an indication of whether the beam failure is associated with SI or CLI; and receive, based on the BFR request, a BFR response indicating one or more beam switching parameters, the BFR request including an indication of whether the beam failure is associated with SI or CLI.

[0009] Another apparatus for wireless communication at a UE is described. The apparatus may include: means for identifying a beam failure of at least one communication beam at the UE; means for sending, via a sidelink channel, a BFR request to a network entity that includes an indication of whether the beam failure is associated with SI or CLI; and means for receiving, based on the BFR request, a BFR response indicating one or more beam switching parameters, the BFR request including an indication of whether the beam failure is associated with SI or CLI.

[0010] A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to perform the following operations: identify a beam failure of at least one communication beam at the UE; send a BFR request via a sidelink channel to a network entity, the BFR request including an indication of whether the beam failure is associated with SI or CLI; and receive a BFR response indicating one or more beam switching parameters based on the BFR request, the BFR request including an indication of whether the beam failure is associated with SI or CLI.

[0011] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for the following actions: receive an indication of one or more resources associated with a set of multiple beam failure detection reference signals from a network entity; and periodically obtain at least one of a reference signal received power measurement, an SI measurement, and a CLI measurement based on the one or more resources.

[0012] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, sending the BFR request may include operations, features, components, or instructions for sending control signaling that includes at least one of the following: an indication of increased SI, an indication of increased CLI, an identifier of SI that caused the beam failure, an identifier of CLI that caused the beam failure, a CLI beam indication that caused the CLI, an uplink beam identifier that caused the SI, a transmit-receive point identifier associated with the beam failure, a UE identifier, a cell identifier, an indication of a set of preferred beams for downlink or uplink or both, or a combination thereof.

[0013] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for the following actions: identify a set of multiple sidelink relay UEs for sending the BFR request; and select a sidelink relay UE from the set of multiple sidelink relay UEs for sending the BFR request based on determining that the UE may be able to connect to the sidelink relay UE using a latency value that meets a threshold latency value.

[0014] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for identifying a set of sidelink relay UEs for transmitting a BFR request based on each sidelink relay UE among a plurality of sidelink relay UEs being associated with at least one of the following: a threshold sidelink latency, a threshold uplink latency, a threshold sidelink link quality, a threshold uplink link quality, a sidelink relay mode setting parameter, the connectivity between each sidelink relay UE and a network entity, the connectivity between each sidelink relay UE and a second network entity, or a combination thereof.

[0015] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, transmitting a BFR request may include operations, features, components, or instructions for the following actions: transmitting a BFR request to a sidelink relay UE in a set of a plurality of sidelink relay UEs based on one or more conditions.

[0016] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for the following actions: receiving an indication of a threshold latency value from a network entity, where the threshold latency value may be periodic based on a random access channel configuration.

[0017] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, a UE may be able to connect to a sidelink relay UE using a sidelink grant or a sensed sidelink resource.

[0018] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for receiving an indication from a sidelink relay UE of at least one of the following: the availability of an uplink grant at the sidelink relay UE, the periodicity associated with the uplink grant, the offset associated with the uplink grant, the delay between two uplink grants, the time and frequency resources per occasion, the physical layer uplink priority, or a combination thereof, where the uplink grant availability may be based on scheduling request information, configured grant information, dynamic grant information.

[0019] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for the following actions: receiving from a sidelink relay UE signaling indicating the downlink quality or the estimated uplink quality or both for each cell identifier or network entity identifier associated with the sidelink relay UE, where the signaling includes broadcast signaling or unicast signaling.

[0020] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for the following actions: receiving, from a sidelink relay UE, an indicator indicating the relay capability of the sidelink relay UE, where the indicator may be received periodically or cyclically.

[0021] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for the following actions: receiving, from a sidelink relay UE, at least one of a distributed unit identifier, a transmit receive point identifier, a cell identifier, a network entity identifier, or a combination thereof.

[0022] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, receiving a BFR response may include operations, features, components, or instructions for receiving a BFR response that indicates a change in an uplink beam or a downlink beam for a UE based on whether the beam failure is associated with SI or may be associated with CLI.

[0023] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, receiving a BFR response may include operations, features, components, or instructions for receiving a BFR response that includes a request for the UE to switch from a full-duplex (FD) mode to a half-duplex (HD) mode.

[0024] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, receiving a BFR response may include operations, features, components, or instructions for receiving a BFR response that initiates a beam training process using at least one of a reference signal received power measurement resource, an SI measurement resource, and a CLI measurement resource, and performing the beam training process to establish a second communication beam.

[0025] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, receiving a BFR response may include operations, features, components, or instructions for receiving a BFR response that includes a command to reduce the power associated with an uplink beam at the UE, where the BFR response may be based on the beam failure being associated with SI.

[0026] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, receiving a BFR response may include operations, features, components, or instructions for receiving a BFR response that includes a command for the UE to switch a first uplink beam to a second uplink beam, where the first uplink beam may have a greater signal interference with at least one communication beam than the second uplink beam, and where the BFR response may be based on the beam failure being associated with SI.

[0027] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for the following actions: determining that the signal interference between a second uplink beam and at least one communication beam may be greater than a threshold; and switching from the FD mode to the HD mode or canceling the uplink transmission based on the signal interference being greater than the threshold.

[0028] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, receiving a BFR response may include operations, features, components, or instructions for receiving a BFR response that includes a trigger to initiate a process for uplink beam selection with signal interference measurement, where the BFR response may be associated with a beam failure and the CLI.

[0029] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for the following actions: sending a set of intermediate CLI reports to a second UE associated with the CLI based on identifying a beam failure; identifying a set of beams that meet the CLI threshold based on sending the set of intermediate CLI reports; and sending an indication of the set of beams that meet the CLI threshold.

[0030] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the indication of the set of beams that meet the CLI threshold may be sent from the UE to a network entity or sent to the network entity via a second UE.

[0031] A method for wireless communication at a network entity is described. The method may include: receiving a BFR request from a first UE, the BFR request including an indication of whether a beam failure at a second UE is associated with SI or the CLI; identifying one or more beam switching parameters based on the BFR request including the indication of whether the beam failure is associated with SI or the CLI; and sending a BFR response indicating the one or more beam switching parameters.

[0032] An apparatus for wireless communication at a network entity is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to: receive a BFR request from a first UE, the BFR request including an indication of whether a beam failure at a second UE is associated with SI or the CLI; identify one or more beam switching parameters based on the BFR request including the indication of whether the beam failure is associated with SI or the CLI; and send a BFR response indicating the one or more beam switching parameters.

[0033] Describes another apparatus for wireless communication at a network entity. The apparatus may include: means for receiving a BFR request from a first UE, the BFR request including an indication of whether a beam failure at a second UE is associated with SI or CLI; means for identifying one or more beam switching parameters based on the BFR request including an indication of whether the beam failure is associated with SI or CLI; and means for transmitting a BFR response indicating the one or more beam switching parameters.

[0034] Describes a non-transitory computer-readable medium storing code for wireless communication at a network entity. The code may include instructions executable by a processor to: receive a BFR request from a first UE, the BFR request including an indication of whether a beam failure at a second UE is associated with SI or CLI; identify one or more beam switching parameters based on the BFR request including an indication of whether the beam failure is associated with SI or CLI; and transmit a BFR response indicating the one or more beam switching parameters.

[0035] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, transmitting the BFR response may include operations, features, means, or instructions for transmitting a BFR response that indicates a change in an uplink beam or a downlink beam for a second UE based on whether the beam failure is associable with SI or CLI.

[0036] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, transmitting the BFR response may include operations, features, means, or instructions for transmitting a BFR response that includes a request for the second UE to switch from an FD mode to an HD mode.

[0037] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, transmitting the BFR response may include operations, features, means, or instructions for transmitting a BFR response that initiates a beam training process using at least one of a reference signal received power measurement resource, an SI measurement resource, and a CLI measurement resource.

[0038] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, transmitting the BFR response may include operations, features, means, or instructions for transmitting a BFR response that includes a command to reduce the power associated with an uplink beam at a second UE, where the BFR response may be based on the beam failure being associated with SI.

[0039] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, sending a BFR response may include operations, features, components, or instructions for sending the BFR response, the BFR response including a command for a second UE to switch a first uplink beam to a second uplink beam, where the first uplink beam may have a greater signal interference with a downlink beam than the second uplink beam, and where the BFR response may be associated with SI based on a beam failure.

[0040] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, sending a BFR response may include operations, features, components, or instructions for sending the BFR response, the BFR response including a trigger to initiate a process for uplink beam selection with signal interference measurement, where the BFR response may be associated with CLI based on a beam failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Examples of wireless communication systems supporting sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure are illustrated.

[0042] Figure 2 Examples of wireless communication systems supporting sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure are illustrated.

[0043] Figure 3 Examples of process flows supporting sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure are illustrated.

[0044] Figure 4 Examples of wireless communication systems supporting sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure are illustrated.

[0045] Figure 5 Examples of process flows supporting sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure are illustrated.

[0046] Figure 6 and Figure 7 Block diagrams of devices supporting sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure are shown.

[0047] Figure 8 Block diagrams of communication managers supporting sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure are shown.

[0048] Figure 9 Diagrams of systems including devices supporting sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure are shown.

[0049] Figure 10 and Figure 11 shows a block diagram of a device supporting sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure.

[0050] Figure 12 shows a block diagram of a communication manager supporting sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure.

[0051] Figure 13 shows a diagram of a system including a device supporting sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure.

[0052] Figures 14 to 20 shows a flowchart illustrating a method supporting sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure. DETAILED DESCRIPTION

[0053] A wireless communication system may support one or more wireless devices (e.g., user equipment (UE), network entities) operating in different modes. For example, a UE may operate in a full-duplex (FD) mode, a network entity may operate in an FD mode, or a network entity and a UE may operate in a flexible time-division duplex (TDD) mode. In some cases, wireless devices operating in multiple modes may experience beam failure due to different types of interference. For example, self-interference (SI) may occur when a signal leaks from a transmitter of a first device to a receiver of the first device. In other examples, cross-link interference (CLI) may occur when multiple network entities and corresponding UEs transmit and receive simultaneously and in the same, overlapping, or non-overlapping frequency bands. In some wireless communication systems, a beam failure recovery (BFR) process may be implemented to enable a network entity to switch from a failed downlink beam of a UE to a new operating downlink beam of the UE. Additionally or alternatively, the one or more UEs may indicate to the network entity that the beam failure is due to SI or CLI. In some cases, the network entity may receive an indication of the type of beam failure and may switch the downlink beam or uplink beam of the UE, or manage interference through joint optimization. In some examples, a UE indicates a BFR request (e.g., a BFR indication) via a physical random access channel (PRACH) to identify candidate beams for the UE to transmit on. However, in some wireless communication systems, a random access channel (RACH) sequence or timing may include mapping additional bits to separate one or more RACH sequences or timings to convey the beam failure reason, and may increase latency and power consumption.

[0054] The described technology relates to improved methods, systems, devices, or apparatuses that support sidelink-assisted indication of beam failures. In some wireless communication systems, when a beam failure has occurred at a network entity, a BFR request from a UE may be sent using a sidelink channel. In some examples, the BFR request includes an indication of whether the beam failure is due to SI or CLI. In some cases, the UE may determine the type of beam failure, such as an increase in SI or CLI or a decrease in downlink reference signal received power (RSRP). In some examples, the UE may check interference measurements against a type of threshold and may indicate that SI or CLI has caused the beam failure. In some examples, the UE may indicate that the beam failure is the result of SI or CLI, and the downlink RSRP may still support communication in a half-duplex (HD) mode.

[0055] In some embodiments, the wireless communication system may support solutions that enable a UE to convey an indication of a beam failure caused by SI or CLI to a network entity via a sidelink or an uplink RACH. In some examples, the UE may detect the beam failure and the cause of the beam failure. The UE may include the detection and cause of the beam failure in a BFR request via a sidelink to another UE. In some cases, this other UE may send the BFR request on the uplink to the network entity, where the network entity receives the request and identifies one or more beam switching parameters. The network entity may indicate candidate beams for the UE to use in a BFR response sent to the UE via a sidelink or a downlink.

[0056] In some aspects, the UE may determine the conditions for using a sidelink and whether another UE in the wireless communication system may send a BFR request. In some examples, the BFR request may include a BFR medium access control (MAC) control element (CE). In some examples, the UE may determine whether a sidelink relay UE may relay a BFR request based on some conditions. In some cases, the network entity may construct a BFR response (e.g., a BFR MAC-CE response) for multiple types of beam failures and may determine the UE response for each type of beam failure. Additionally or alternatively, the BFR response may include a response to a beam failure caused by SI or CLI. In some cases, the BFR response may include the behavior for each type of response at the UE, and wherein the network entity may send the BFR response.

[0057] Certain aspects of the subject matter described herein may be implemented to achieve one or more potential advantages. The described techniques may provide reduced latency, as sidelink transmission speeds may exceed those of the BFR RACH procedure. In some cases, the RACH latency (e.g., RACH configuration periodicity) is large (e.g., 40 milliseconds (ms)), and sidelink transmissions occur more frequently. Additionally, the wireless communication system may create an alternative path for BFR information. In some cases, the downlink and uplink beams may be blocked, and transmitting via the sidelink may provide an alternative path from the UE to the network entity. In some aspects, the wireless communication system may transmit less frequently and reduce the power overhead via the sidelink compared to using the PRACH procedure. In some cases, the sidelink currently used to relay BFR information may be established for multi-link connectivity purposes, where using the same sidelink may reduce latency and signaling overhead. Thus, the wireless communication system may use the sidelink to reduce resource contention and improve the BFR procedure.

[0058] Aspects of the present disclosure are first described in the context of a wireless communication system and a process flow. Aspects of the present disclosure are further illustrated and described by way of apparatus diagrams, system diagrams, and flowcharts related to sidelink-assisted indication of beam failure.

[0059] Figure 1 An example of a wireless communication system 100 that supports sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure is illustrated. The wireless communication system 100 may include one or more network entities 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, a New Radio (NR) network, or a network operating in accordance with other systems and radio technologies, including future systems and radio technologies not explicitly mentioned herein.

[0060] The network entity 105 can be dispersed throughout a geographic area to form a wireless communication system 100 and can include devices in different forms or with different capabilities. In various examples, the network entity 105 can be referred to as a network element, a mobility element, a radio access network (RAN) node, or network equipment, among other designations. In some examples, the network entity 105 and the UE 115 can communicate wirelessly via one or more communication links 125 (e.g., radio frequency (RF) access links). For example, the network entity 105 can support a coverage area 110 (e.g., a geographic coverage area) within which the UE 115 and the network entity 105 can establish one or more communication links 125. The coverage area 110 can be an example of a geographic area within which the network entity 105 and the UE 115 can support signal communication according to one or more radio access technologies (RATs).

[0061] The UEs 115 can be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 can be stationary or mobile or stationary and mobile at different times. The UEs 115 can be devices in different forms or with different capabilities. Figure 1 Some example UEs 115 are illustrated herein. The UEs 115 described herein can be capable of supporting communication with various types of devices (such as other UEs 115 or network entities 105 as Figure 1 shown).

[0062] As described herein, a node of the wireless communication system 100 (which may be referred to as a network node or a wireless node) may be a network entity 105 (e.g., any network entity described herein), a UE 115 (e.g., any UE described herein), a network controller, a device, an apparatus, a computing system, one or more components, or another suitable processing entity configured to perform any of the techniques described herein. For example, the node may be a UE 115. As another example, the node may be a network entity 105. As yet another example, a first node may be configured to communicate with a second node or a third node. In one aspect of this example, the first node may be a UE 115, the second node may be a network entity 105, and the third node may be a UE 115. In another aspect of this example, the first node may be a UE 115, the second node may be a network entity 105, and the third node may be a network entity 105. In other aspects of this example, the first node, the second node, and the third node may be different from these examples. Similarly, references to UE 115, network entity 105, device, apparatus, computing system, etc. may include the disclosure of UE 115, network entity 105, device, apparatus, computing system, etc. as nodes. For example, the disclosure that UE 115 is configured to receive information from network entity 105 also discloses that a first node is configured to receive information from a second node.

[0063] In some examples, network entity 105 may communicate with core network 130 or with each other or both. For example, network entity 105 may communicate with core network 130 via one or more backhaul communication links 120 (e.g., according to S1, N2, N3, or other interface protocols). In some examples, network entity 105 may communicate with each other directly (e.g., directly between network entities 105) or indirectly (e.g., via core network 130) via backhaul communication links 120 (e.g., according to X2, Xn, or other interface protocols). In some examples, network entity 105 may communicate with each other via midhaul communication link 162 (e.g., according to midhaul interface protocol) or fronthaul communication link 168 (e.g., according to fronthaul interface protocol) or any combination thereof. Backhaul communication link 120, midhaul communication link 162, or fronthaul communication link 168 may be or include one or more wired links (e.g., electrical link, optical fiber link), one or more wireless links (e.g., radio link, wireless optical link), etc. or various combinations thereof. UE 115 may communicate with core network 130 via communication link 155.

[0064] One or more of the network entities 105 described herein may include or may be referred to as a base station 140 (e.g., transceiver base station, radio base station, NR base station, access point, radio transceiver, Node B, evolved Node B (eNB), next-generation Node B or giga Node B (either of which may be referred to as gNB), 5G NB, next-generation eNB (ng-eNB), home Node B, home evolved Node B or other suitable terms). In some examples, the network entity 105 (e.g., base station 140) may be implemented in an integrated (e.g., monolithic, stand-alone) base station architecture that may be configured to utilize a protocol stack physically or logically integrated within a single network entity 105 (e.g., a single RAN node, such as base station 140).

[0065] In some examples, the network entity 105 may be implemented in a disaggregated architecture (e.g., disaggregated base station architecture, disaggregated RAN architecture) that may be configured to utilize a protocol stack physically or logically distributed between two or more network entities 105 (such as an integrated access backhaul (IAB) network, open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance) or virtualized RAN (vRAN) (e.g., cloud RAN (C-RAN)). For example, the network entity 105 may include one or more of the following: a central unit (CU) 160, a distributed unit (DU) 165, a radio unit (RU) 170, a RAN intelligent controller (RIC) 175 (e.g., near-real-time RIC (near-RT RIC), non-real-time RIC (non-RT RIC)), a service management and orchestration (SMO) 180 system or any combination thereof. The RU 170 may also be referred to as a radio head, intelligent radio head, remote radio head (RRH), remote radio unit (RRU) or transmit receive point (TRP). One or more components of the network entity 105 in a disaggregated RAN architecture may be co-located, or one or more components of the network entity 105 may be located in distributed locations (e.g., separate physical locations). In some examples, one or more network entities 105 of the disaggregated RAN architecture may be implemented as virtual units (e.g., virtual CU (VCU), virtual DU (VDU), virtual RU (VRU)).

[0066] The functional split between the CU 160, DU 165, and RU 170 is flexible and can support different functions, depending on which functions are performed at the CU 160, DU 165, or RU 170 (e.g., network layer functions, protocol layer functions, baseband functions, RF functions, and any combination thereof). For example, a functional split of the protocol stack can be adopted between the CU 160 and DU 165 such that the CU 160 can support one or more layers of the protocol stack and the DU 165 can support one or more different layers of the protocol stack. In some examples, the CU 160 can host higher protocol layer (e.g., layer 3 (L3), layer 2 (L2)) functions and signaling (e.g., radio resource control (RRC), service data adaptation protocol (SDAP), packet data convergence protocol (PDCP)). The CU 160 can be connected to one or more DU 165s or RU 170s, and one or more DU 165s or RU 170s can host lower protocol layers, such as layer 1 (L1) (e.g., physical (PHY) layer) or L2 (e.g., radio link control (RLC) layer, medium access control (MAC) layer) functions and signaling, and can each be at least partially controlled by the CU 160. Additionally or alternatively, a functional split of the protocol stack can be adopted between the DU 165 and RU 170 such that the DU 165 can support one or more layers of the protocol stack and the RU 170 can support one or more different layers of the protocol stack. The DU 165 can support one or more different cells (e.g., via one or more RU 170s). In some cases, the functional split between the CU 160 and DU 165 or between the DU 165 and RU 170 can be within a protocol layer (e.g., some functions of a protocol layer can be performed by one of the CU 160, DU 165, or RU 170, while other functions of that protocol layer are performed by a different one of the CU 160, DU 165, or RU 170). The CU 160 can be further functionally split into a CU control plane (CU-CP) and a CU user plane (CU-UP) function. The CU 160 can be connected to one or more DU 165s via an intermediate transport communication link 162 (e.g., F1, F1-c, F1-u), and the DU 165 can be connected to one or more RU 170s via a fronthaul communication link 168 (e.g., open fronthaul (FH) interface). In some examples, the intermediate transport communication link 162 or the fronthaul communication link 168 can be implemented according to the interfaces (e.g., channels) between the layers of the protocol stack, which are supported by the respective network entities 105 communicating via such communication links.

[0067] In a wireless communication system (e.g., wireless communication system 100), the infrastructure and spectrum resources for radio access may support wireless backhaul link capabilities to supplement wired backhaul connections, thereby providing an IAB network architecture (e.g., to core network 130). In some cases, in an IAB network, one or more network entities 105 (e.g., IAB node 104) may be partially controlled by each other. One or more IAB nodes 104 may be referred to as donor entities or IAB donors. One or more DUs 165 or one or more RUs 170 may be partially controlled by one or more CUs 160 associated with a donor network entity 105 (e.g., donor base station 140). One or more donor network entities 105 (e.g., IAB donors) may communicate with one or more additional network entities 105 (e.g., IAB nodes 104) via the supported access and backhaul links (e.g., backhaul communication link 120). An IAB node 104 may include an IAB mobile terminal (IAB-MT) controlled (e.g., scheduled) by a DU 165 of a coupled IAB donor. The IAB-MT may include a separate antenna set for relaying communication with a UE 115 or may share the same antenna (e.g., of an RU 170 of the IAB node 104) for access via the DU 165 of the IAB node 104 (e.g., referred to as a virtual IAB-MT (vIAB-MT)). In some examples, the IAB node 104 may include a DU 165 that supports communication links with additional entities (e.g., IAB nodes 104, UEs 115) within a relay chain or configuration (e.g., downstream) of the access network. In such cases, one or more components of the split RAN architecture (e.g., one or more IAB nodes 104 or components of the IAB node 104) may be configured to operate according to the techniques described herein.

[0068] For example, the access network (AN) or RAN may include communication between an access node (e.g., an IAB donor), an IAB node 104, and one or more UEs 115. The IAB donor may facilitate the connection between the core network 130 and the AN (e.g., via a wired or wireless connection to the core network 130). That is, the IAB donor may refer to a RAN node having a wired or wireless connection to the core network 130. The IAB donor may include a CU 160 and at least one DU 165 (e.g., and an RU 170), where the CU 160 may communicate with the core network 130 via an interface (e.g., a fronthaul link). The IAB donor and the IAB node 104 may communicate via an F1 interface according to a protocol that defines signaling messages (e.g., the F1 AP protocol). Additionally or alternatively, the CU 160 may communicate with the core network via an interface (which may be an example of a part of the fronthaul link) and may communicate with other CUs 160 (e.g., CUs 160 associated with alternative IAB donors) via an Xn-C interface (which may be an example of a part of the fronthaul link).

[0069] The IAB node 104 may refer to a RAN node that provides IAB functionality (e.g., access for UEs 115, wireless self-backhaul capabilities, etc.). The DU 165 may act as a distributed scheduling node towards the child nodes associated with the IAB node 104, and the IAB-MT may act as a scheduled node towards the parent node associated with the IAB node 104. That is, the IAB donor may be referred to as a parent node that communicates with one or more child nodes (e.g., the IAB donor may relay transmissions for UEs through one or more other IAB nodes 104). Additionally or alternatively, depending on the relay chain or configuration of the AN, the IAB node 104 may also be referred to as a parent node or a child node of other IAB nodes 104. Thus, the IAB-MT entity of the IAB node 104 may provide a Uu interface for a child IAB node 104 to receive signaling from the parent IAB node 104, and a DU interface (e.g., the DU 165) may provide a Uu interface for the parent IAB node 104 to signal to the child IAB node 104 or the UE 115.

[0070] For example, the IAB node 104 can be referred to as a parent node supporting communication for a child IAB node or as a child IAB node associated with an IAB donor, or both. The IAB donor can include a CU 160 having a wired or wireless connection to the core network 130 (e.g., a fronthaul communication link 120), and can act as the parent node of the IAB node 104. For example, the DU 165 of the IAB donor can relay transmissions to the UE 115 via the IAB node 104, or can signal transmissions directly to the UE 115, or both. The CU 160 of the IAB donor can signal communication link establishment to the IAB node 104 via the F1 interface, and the IAB node 104 can schedule transmissions (e.g., transmissions relayed from the IAB donor to the UE 115) via the DU 165. That is, data can be relayed to and from the IAB node 104 via signaling over the NR Uu interface to the MT of the IAB node 104. Communication with the IAB node 104 can be scheduled by the DU 165 of the IAB donor, and communication with the IAB node 104 can be scheduled by the DU 165 of the IAB node 104.

[0071] In the case where the techniques described herein are applied in the context of a split RAN architecture, one or more components of the split RAN architecture can be configured to support sidelink-assisted indication of beam failures as described herein. For example, some operations described as being performed by the UE 115 or a network entity 105 (e.g., a base station 140) can additionally or alternatively be performed by one or more components of the split RAN architecture (e.g., the IAB node 104, the DU 165, the CU 160, the RU 170, the RIC 175, the SMO 180).

[0072] The UE 115 can include or can be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable term, where "device" can also be referred to as a unit, a station, a terminal, or a client, etc. The UE 115 can also include or can be referred to as a personal electronic device, such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, the UE 115 can include or can be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communication (MTC) device, etc., which can be implemented in various objects such as appliances or vehicles, meters, etc.

[0073] The UE 115 described herein can be capable of communicating with various types of devices such as other UEs 115 that can sometimes act as relays, as well as network entities 105 and network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, etc., as Figure 1as shown

[0074] UE 115 and network entity 105 may wirelessly communicate with each other via one or more communication links 125 (e.g., access links) using resources associated with one or more carriers. The term "carrier" may refer to a set of RF spectrum resources having a defined physical layer structure for supporting communication link 125. For example, a carrier for communication link 125 may include a portion (e.g., bandwidth part (BWP)) of an RF spectrum band operating according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling for coordinating carrier operation, user data, or other signaling. Wireless communication system 100 may support communication with UE 115 using carrier aggregation or multi-carrier operation. According to a carrier aggregation configuration, UE 115 may be configured to have multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation may be used for both frequency division duplex (FDD) and time division duplex (TDD) component carriers. Communication between network entity 105 and other devices may refer to communication between these devices and any part (e.g., entity, sub-entity) of network entity 105. For example, the terms "transmit", "receive", or "communicate" when referring to network entity 105 may refer to any part of network entity 105 of the RAN (e.g., base station 140, CU 160, DU 165, RU 170) communicating with another device (e.g., directly or via one or more other network entities 105).

[0075] In some examples, such as in a carrier aggregation configuration, a carrier may also have acquisition signaling or control signaling for coordinating the operation of other carriers. A carrier may be associated with a frequency channel (e.g., evolved universal mobile telecommunications system terrestrial radio access (E-UTRA) absolute RF channel number (EARFCN)) and may be identified according to a channel raster for discovery by UE 115. A carrier may operate in stand-alone mode, in which case initial acquisition and connection may be performed by UE 115 via the carrier, or the carrier may operate in non-stand-alone mode, in which case the connection is anchored using a different carrier (e.g., different carriers of the same or different radio access technologies).

[0076] The communication link 125 shown in the wireless communication system 100 may include a downlink transmission (e.g., forward link transmission) from the network entity 105 to the UE 115, an uplink transmission (e.g., reverse link transmission) from the UE 115 to the network entity 105, or other transmission configurations such as both. A carrier may carry downlink communication or uplink communication (e.g., in FDD mode), or may be configured to carry both downlink communication and uplink communication (e.g., in TDD mode).

[0077] The signal waveform transmitted via a carrier may include multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element may refer to the resource of one symbol period (e.g., the duration of one modulation symbol) and one subcarrier. In this case, the symbol period and the subcarrier spacing may be inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the decoding rate of the modulation scheme, or both), such that a relatively large number of resource elements (e.g., during the transmission duration) and a relatively high-order modulation scheme may correspond to a relatively high communication rate. Wireless communication resources may refer to a combination of RF spectrum resources, time resources, and space resources (e.g., spatial layers or beams), and the use of multiple space resources may increase the data rate or data integrity for communication with the UE 115.

[0078] The time intervals for the network entity 105 or the UE 115 can be expressed as multiples of a basic time unit, which may refer to, for example, the sampling period T s =1 / (Δf max ·N f ) seconds, where Δf max may represent the supported subcarrier spacing, and N f may represent the supported discrete Fourier transform (DFT) size. The time intervals of the communication resources may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0079] Each frame may include a plurality of consecutively numbered sub - frames or time slots, and each sub - frame or time slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into sub - frames, and each sub - frame may be further divided into a certain number of time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the sub - carrier spacing. Each time slot may include a certain number of symbol periods (e.g., depending on the length of the cyclic prefix appended to each symbol period). In some wireless communication systems 100, a time slot may be further divided into a plurality of mini - time slots associated with one or more symbols. Excluding the cyclic prefix, each symbol period may be associated with one or more (e.g., N f

[0080]

[0081]

[0082] sub - frames, time slots, mini - time slots, or symbols may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in a burst of shortened TTIs (sTTIs)).According to various techniques, carriers can be used to multiplex physical channels for communication. For example, one or more of time - division multiplexing (TDM) techniques, frequency - division multiplexing (FDM) techniques, or hybrid TDM - FDM techniques can be used to multiplex physical control channels and physical data channels for signaling via a downlink carrier. The control region of a physical control channel (e.g., a control resource set (CORESET)) may be defined by a set of symbol periods and may extend across the system bandwidth of a carrier or a subset of that system bandwidth. One or more control regions (e.g., CORESETs) may be configured for a set of UEs 115. For example, one or more of the UEs 115 may monitor or search a control region for control information according to one or more search space sets, and each search space set may include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. The aggregation level of a control channel candidate may refer to the amount of control channel resources (e.g., control channel elements (CCEs)) associated with the coded information for a control information format with a given payload size. The search space set may include: a common search space set configured to transmit control information to a plurality of UEs 115, and a UE - specific search space set for transmitting control information to a specific UE 115.​The network entity 105 may provide communication coverage via one or more cells (e.g., macro cells, small cells, hotspots, or other types of cells, or any combination thereof). The term "cell" may refer to a logical communication entity for communicating with the network entity 105 (e.g., using a carrier), and may be associated with an identifier for distinguishing adjacent cells (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or other cell identifier). In some examples, a cell may also refer to a coverage area 110 or a portion of the coverage area 110 (e.g., a sector) over which the logical communication entity operates. Depending on various factors such as the capabilities of the network entity 105, the scope of such cells can range from a smaller area (e.g., a structure, a subset of a structure) to a larger area. For example, a cell may be or may include a building, a subset of a building, or an external space between or overlapping the coverage areas 110, etc.

[0083] Macro cells generally cover a relatively large geographical area (e.g., with a radius of several kilometers) and may allow unrestricted access to UEs 115 having a service subscription with the network provider supporting the macro cell. Compared with macro cells, small cells may be associated with a lower power network entity 105 (e.g., a lower power base station 140), and small cells may operate using the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to UEs 115 having a service subscription with the network provider, or may provide restricted access to UEs 115 associated with the small cell (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 associated with users in a home or office). The network entity 105 may support one or more cells and may also use one or more component carriers to support communication via one or more cells.

[0084] In some examples, a carrier may support multiple cells and may be configured with different cell types according to different protocol types that may provide access for different types of devices (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB)).

[0085] In some examples, network entity 105 (e.g., base station 140, RU 170) can be movable and thus provide communication coverage for a moving coverage area 110. In some examples, different coverage areas 110 associated with different technologies can overlap, but different coverage areas 110 can be supported by the same network entity 105. In some other examples, overlapping coverage areas 110 associated with different technologies can be supported by different network entities 105. The wireless communication system 100 can include, for example, a heterogeneous network in which different types of network entities 105 use the same or different radio access technologies to provide coverage for various coverage areas 110.

[0086] Some UEs 115 can be configured to operate in power consumption reduction modes, such as half-duplex communication (e.g., a mode that supports one-way communication via transmission or reception but not concurrent transmission and reception). In some examples, half-duplex communication can be performed at reduced peak rates. Other energy-saving techniques for UEs 115 include: entering a power-saving deep sleep mode when not participating in active communication, operating using limited bandwidth (e.g., according to narrowband communication), or a combination of these techniques. For example, some UEs 115 can be configured to operate using a narrowband protocol type associated with a defined portion or range (e.g., a set of subcarriers or resource blocks (RBs)) within a carrier, within a guard band of the carrier, or outside the carrier.

[0087] The wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC). UEs 115 can be designed to support ultra-reliable or low-latency or critical functions. Ultra-reliable communication can include private communication or group communication and can be supported by one or more services (such as push-to-talk, video, or data). Support for ultra-reliable, low-latency functions can include prioritization of services, and such services can be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, and ultra-reliable low-latency can be used interchangeably herein.

[0088] In some examples, UE 115 may be configured to support direct communication with other UEs 115 via a device-to-device (D2D) communication link 135 (e.g., according to a peer-to-peer (P2P), D2D, or sidelink protocol). In some examples, one or more UEs 115 performing D2D communication in a group may be within the coverage area 110 of a network entity 105 (e.g., base station 140, RU 170), and this network entity may support aspects of such D2D communication configured (e.g., scheduled) by the network entity 105. In some examples, one or more UEs 115 in such a group may be outside the coverage area 110 of the network entity 105, or may otherwise be unable or not configured to receive transmissions from the network entity 105. In some examples, a group of UEs 115 communicating via D2D communication may support a one-to-many (1:M) system, where each UE 115 sends to each of the other UEs 115 in the group. In some examples, the network entity 105 may facilitate the scheduling of resources for D2D communication. In some other examples, D2D communication may be performed between UEs 115 without involving the network entity 105.

[0089] In some systems, the D2D communication link 135 may be an example of a communication channel (such as a sidelink communication channel) between vehicles (e.g., UE 115). In some examples, vehicles may communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these. Vehicles may signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information related to the V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure (such as roadside units), or communicate with the network via one or more network nodes (e.g., network entity 105, base station 140, RU 170) using vehicle-to-network (V2N) communication, or both.

[0090] The core network 130 can provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 can be an evolved packet core (EPC) or a 5G core (5GC), which can include at least one control plane entity for managing access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) and at least one user plane entity for routing packets or interconnecting to an external network (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity can manage non-access stratum (NAS) functions, such as the mobility, authentication, and bearer management of a UE 115 served by a network entity 105 (e.g., a base station 140) associated with the core network 130. User IP packets can be passed through the user plane entity, which can provide IP address allocation and other functions. The user plane entity can be connected to the IP services 150 of one or more network operators. The IP services 150 can include access to the Internet, an intranet, an IP multimedia subsystem (IMS), or packet switched streaming services.

[0091] The wireless communication system 100 can operate using one or more frequency bands in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or the decimeter band because, in terms of length, the wavelength range is from approximately one decimeter to one meter. UHF waves can be blocked or redirected by buildings and environmental features (which can be referred to as clutter), but these waves can be sufficient to penetrate structures so that macrocells can serve UEs 115 located indoors. Compared to communication using smaller frequencies and longer wavelengths in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz, communication using UHF waves can be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers).

[0092] The wireless communication system 100 may also operate using the super high frequency (SHF) region (also known as the centimeter band) in the range of 3 GHz to 30 GHz or using the extremely high frequency (EHF) region of the spectrum (e.g., 30 GHz to 300 GHz) (also known as the millimeter band). In some examples, the wireless communication system 100 may support millimeter wave (mmW) communication between the UE 115 and the network entity 105 (e.g., the base station 140, the RU 170), and the EHF antennas of the corresponding devices may be smaller and closer spaced than UHF antennas. In some examples, such techniques may facilitate the use of antenna arrays within the device. However, the propagation of EHF transmissions may be affected by greater attenuation and shorter range than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions using one or more different frequency regions, and the use of frequency bands designated across these frequency regions may vary by country or regulatory body.

[0093] The wireless communication system 100 may utilize licensed and unlicensed RF spectrum bands. For example, the wireless communication system 100 may use an unlicensed band (such as the 5 GHz industrial, scientific, and medical (ISM) band) to employ licensed-assisted access (LAA), long term evolution unlicensed (LTE-U) radio access technology, or NR technology. When operating using an unlicensed RF spectrum band, devices such as the network entity 105 and the UE 115 may employ carrier sensing for collision detection and avoidance. In some examples, operation using an unlicensed band may be based on a carrier aggregation configuration (e.g., LAA) in combination with operation using a licensed band component carrier. Operation using unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer (P2P) transmissions, device-to-device (D2D) transmissions, and so on.

[0094] The network entity 105 (e.g., the base station 140, the RU 170) or the UE 115 may be equipped with multiple antennas that may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. The antennas of the network entity 105 or the UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operation or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, the antennas or antenna arrays associated with the network entity 105 may be located at different geographical locations. The network entity 105 may include an antenna array having a set of antenna ports in multiple rows and columns that the network entity 105 may use to support beamforming for communication with the UE 115. Similarly, the UE 115 may include one or more antenna arrays, which may support various MIMO or beamforming operations. Additionally or alternatively, an antenna panel may support RF beamforming for signals transmitted via the antenna ports.

[0095] Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that can be used at a transmitting device or a receiving device (e.g., network entity 105, UE 115) to shape or direct an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming can be achieved by combining signals communicated via the antenna elements of an antenna array such that some signals propagating along a particular direction relative to the antenna array experience constructive interference while other signals experience destructive interference. The adjustment of the signals communicated via the antenna elements can include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to the signals carried via the antenna elements associated with the device. The adjustment associated with each of these antenna elements can be defined by a set of beamforming weights associated with a particular direction (e.g., relative to the antenna array of the transmitting device or the receiving device or relative to some other direction).

[0096] Network entity 105 or UE 115 can use beam scanning techniques as part of beamforming operations. For example, network entity 105 (e.g., base station 140, RU 170) can use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) can be sent by network entity 105 multiple times in different directions. For example, network entity 105 can send signals according to different sets of beamforming weights associated with different transmission directions. Transmission along different beam directions can be used to identify (e.g., by the transmitting device such as network entity 105, or by the receiving device such as UE 115) the beam direction for later transmission or reception by network entity 105.

[0097] Some signals (such as data signals associated with a particular receiving device) can be sent by a transmitting device (e.g., transmitting network entity 105, transmitting UE 115) along a single beam direction (e.g., a direction associated with the receiving device such as receiving network entity 105 or receiving UE 115). In some examples, the beam direction associated with transmission along a single beam direction can be determined based on signals transmitted along one or more beam directions. For example, UE 115 can receive one or more of the signals sent by network entity 105 in different directions and can report to network entity 105 an indication of the signal that UE 115 receives with the highest signal quality or other acceptable signal quality.

[0098] In some examples, transmissions performed by a device (e.g., by network entity 105 or UE 115) may be carried out using multiple beam directions, and the device may use a combination of digital precoding or beamforming to generate a combined beam for transmission (e.g., from network entity 105 to UE 115). UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to a configured set of beams across the system bandwidth or one or more sub-bands. Network entity 105 may transmit reference signals (e.g., cell-specific reference signal (CRS), channel state information reference signal (CSI-RS)), which may or may not be precoded. UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., multi-panel type codebook, linear combination type codebook, port selection type codebook). Although these techniques are described with reference to signals transmitted by network entity 105 (e.g., base station 140, RU 170) in one or more directions, UE 115 may use similar techniques for transmitting signals multiple times in different directions (e.g., for identifying beam directions used by UE 115 for subsequent transmission or reception), or for transmitting signals in a single direction (e.g., for transmitting data to a receiving device).

[0099] A receiving device (e.g., UE 115) may perform receiving operations according to multiple receiving configurations (e.g., directional listening) when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from a receiving device (e.g., network entity 105). For example, the receiving device may perform receiving according to multiple receiving directions by: receiving via different antenna sub-arrays, processing the received signals according to different antenna sub-arrays, receiving according to different sets of receive beamforming weights (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or processing the received signals according to different sets of receive beamforming weights applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as "listening" according to different receiving configurations or receiving directions. In some examples, the receiving device may use a single receiving configuration to receive along a single beam direction (e.g., when receiving a data signal). The single receiving configuration may be aligned along a beam direction determined based on listening according to different receiving configuration directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio (SNR), or other acceptable signal quality based on listening according to multiple beam directions).

[0100] The wireless communication system 100 can be a packet-based network that operates according to a hierarchical protocol stack. In the user plane, the communication at the bearer or PDCP layer can be IP-based. The RLC layer can perform packet segmentation and reassembly for conveyance via logical channels. The MAC layer can perform priority handling and multiplexing from logical channels into transport channels. The MAC layer can also implement error detection techniques, error correction techniques, or both to support retransmission to improve link efficiency. In the control plane, the RRC layer can provide the establishment, configuration, and maintenance of the RRC connection that supports the radio bearers for user plane data between the UE 115 and the network entity 105 or the core network 130. The PHY layer can map the transport channels to physical channels.

[0101] The UE 115 and the network entity 105 can support the retransmission of data to increase the likelihood that the data is successfully received. Hybrid automatic repeat request (HARQ) feedback is a technique for increasing the likelihood of correctly receiving data via a communication link (e.g., communication link 125, D2D communication link 135). HARQ can include a combination of error detection (e.g., using cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve the throughput at the MAC layer under poor radio conditions (e.g., low signal-to-noise ratio conditions). In some examples, the device can support same-slot HARQ feedback, in which case the device can provide HARQ feedback for the data received in the previous symbols in a particular slot via that slot. In some other examples, the device can provide HARQ feedback in a subsequent slot or according to some other time interval.

[0102] In some wireless communication systems 100, multiple UEs 115 and network entities 105 may operate in different modes. For example, a UE 115 may operate in the FD mode, a network entity 105 may operate in the FD mode, or a network entity 105 and a UE 115 may operate in the TDD mode. In some cases, a wireless device operating in multiple modes may experience beam failures due to different types of interference. For example, SI may occur when a signal leaks from a transmitter of a UE 115 to a receiver of the UE 115. In other examples, CLI may occur when multiple network entities 105 and corresponding UEs 115 transmit and receive in the same frequency band. In some wireless communication systems 100, a BFR process may be implemented to enable a network entity 105 to switch from a failed uplink beam of a UE 115 to a downlink beam of the UE 115. Additionally or alternatively, one or more UEs 115 may indicate to the network entity 105 that the beam failure is due to SI or CLI. In some cases, the network entity 105 may receive an indication of the type of beam failure and may switch the downlink beam or uplink beam of the UE 115, or jointly manage interference. In some examples, a UE 115 indicates a BFR request via a PRACH to identify candidate beams for the UE 115 to transmit. However, in some wireless communication systems, an RACH sequence or timing may include mapping additional bits to separate one or more RACH sequences or timings, and may increase latency and power consumption.

[0103] In some embodiments, the wireless communication system 100 may support a solution that enables a UE 115 to convey an indication of a beam failure caused by SI or CLI to a network entity 105 via a sidelink or uplink RACH. In some examples, a UE 115 may detect a beam failure and the cause of the beam failure. The UE 115 may include the detection and cause of the beam failure in a BFR request via a sidelink to another UE 115. In some cases, this other UE 115 may send a BFR request to the network entity 105 on the uplink, where the network entity 105 receives the request and identifies one or more beam switching parameters. The network entity 105 may indicate candidate beams for the UE 115 to use in a BFR response sent to the UE 115 via a sidelink or downlink transmission.

[0104] As described herein, UE 115 may determine the conditions for sidelink and whether another UE 115 in the wireless communication system 100 may send a BFR request. In some cases, the BFR request may include a BFR MAC-CE. In some examples, UE 115 may determine whether the sidelink relay UE 115 may relay the BFR request based on some conditions. In some cases, the network entity 105 may construct BFR responses for multiple types of beam failures and may determine how UE 115 responds to each type of beam failure. Additionally or alternatively, the BFR response may include a response to a beam failure due to SI or CLI. In some cases, the BFR response may include the behavior for each type of response at UE 115, and the network entity 105 may send the BFR response.

[0105] Figure 2 An example of a wireless communication system 200 that supports sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure is illustrated. In some examples, the wireless communication system 200 may implement aspects of the wireless communication system 100. The wireless communication system 200 may include UE 115-a, UE 115-b, and UE 115-c, and a network entity 105-a, which may be examples of corresponding devices as described herein (including reference Figure 1 description).

[0106] In some implementations, the wireless communication system 200 may support wireless devices operating in different modes, such as UE 115-a, UE 115-b, and UE 115-c, and the network entity 105-a. For example, one or more UEs 115 may operate in the FD mode such that the UE 115 can transmit and receive simultaneously using corresponding transmit and receive analog beams. In other cases, the network entity 105-a may operate in the FD mode such that the network entity 105-a can transmit and receive simultaneously using transmit and receive analog beams. In some examples, the network entity 105-a and the UE 115 may operate in the TDD mode such that one or more HD network entities 105-a in adjacent cells simultaneously adopt different traffic directions (e.g., downlink in one cell and uplink in another cell).

[0107] In some aspects, a wireless device operating in multiple modes may experience beam failures due to different types of interference. For example, network entity 105-a and UE 115-a may operate in FD mode while communicating using one or more beams. In some cases, a beam failure may occur when network entity 105-a is unable to send a message to UE 115-a via downlink beam 215 due to possible blockage in the path, or if UE 115-a is unable to receive a message from network entity 105-a due to possible blockage. In other examples, UE 115-a operating in multiple modes may suffer from SI or CLI in some beam failure scenarios. For example, SI may occur when a signal leaks from the transmitter of UE 115-a to the receiver of UE 115-a. That is, UE 115-a may send a message via uplink beam 210, which may leak and cause interference 220 to the reception via downlink beam 215, and an alternative communication beam may be required. In other examples, CLI may occur when other wireless devices from neighboring cells are transmitting and receiving simultaneously in the same, overlapping, or adjacent frequency bands. For example, nearby UE 115-b may send communication to network entity 105-a via uplink beam 205, which may interfere with the reception via downlink beam 215 at UE 115-a. In other examples, UE 115-b may send communication to an adjacent network entity via uplink beam 205, which may interfere with the reception via downlink beam 215 at UE 115-a. Knowing that the beam failure is caused by increased SI or CLI may contribute to enhanced BFR.

[0108] According to one or more aspects depicted herein, wireless communication system 200 may implement a BFR process to enable network entity 105-a to switch to other possible beams. For example, network entity 105-a may identify that uplink beam 210 may be interfering with downlink beam 215 and may switch downlink beam 215 to a possible downlink beam 250 or switch uplink beam 210 to a possible uplink beam 255. Additionally or alternatively, wireless communication system 200 may indicate to network entity 105-a that the beam failure is due to SI or CLI. In some cases, an indication of the type of beam failure may allow network entity 105-a to switch downlink beam 215 or uplink beam 210 at UE 115-a, or to jointly manage the interference.

[0109] In some examples, SI may cause a beam failure at UE 115-a. In some cases, the downlink beam 215 at UE 115-a may fail, and UE 115-a may initiate a BFR procedure by sending a BFR request to network entity 105-a. In some examples, the BFR request may include a BFR MAC-CE. In some examples, UE 115-a may send the BFR request to network entity 105-a via an existing uplink allocation. In some cases, UE 115-a may have an uplink grant (e.g., dynamic grant, configured grant) that can be allocated to transmit the BFR request via an uplink grant. UE 115-a may receive a response from network entity 105-a via DCI on a new candidate beam. In some cases, SI may affect the DCI that sends the response. In such cases, the DCI that sends the BFR response is formatted for the HD or BFR search space (SS) and may not have uplink transmission capabilities. In some examples, UE 115-a may send a BFR request and network entity 105-a may miss the uplink transmission. In some cases, network entity 105-a may attempt to schedule a retransmission via the Uu (e.g., access) link SS and may fail due to SI (e.g., deadlock). In such cases, UE 115-a may wait for a period of time (e.g., X milliseconds after sending the BFR MAC-CE) to receive the DCI that schedules the uplink retransmission and the BFR response, and may consider another fallback option for BFR request transmission when the time expires and no response is received. In some examples, UE 115-a may send the BFR request via an existing uplink allocation without using an additional uplink or sidelink grant. In some cases, it may be unrealistic to assume the existence of an uplink grant when the downlink fails. In such cases, UE 115-a may switch to the HD mode when the uplink traffic is not urgent.

[0110] In other examples, UE 115-a may send an uplink special scheduling request (SR) to network entity 105-a to request resources for sending a BFR request. In some cases, network entity 105-a may respond to the SR by providing an uplink grant. In some cases, network entity 105-a may provide the uplink grant via the Uu link in HD mode, via a sidelink, or via a non-faulty downlink (e.g., multiple transmit receive points (mTRP)) to avoid SI. In some cases, UE 115-a may use the provided uplink grant instead of using sidelink resources to transmit the BFR request. In such a case, the latency may be greater than transmitting the BFR via an existing uplink allocation, and the response may be transmitted via a sidelink (with setup) or via the Uu link when switching to HD mode (which may interrupt any ongoing emergency uplink traffic).

[0111] In some embodiments, UE 115-a may send a PRACH (e.g., message 1) on a new candidate FD downlink beam. In some cases, the FD downlink beam exceeds a signal-to-interference-plus-noise ratio (SINR) threshold. In some examples, in both a contention-based random access (CBRA) process and a contention-free random access (CFRA) process, UE 115-a may receive an uplink allocation (e.g., message 2) to send a BFR request. UE 115-a may send a BFR request (e.g., message 3) to network entity 105-a. In some cases, UE 115-a may determine that a candidate FD downlink beam is unavailable and may transmit a RACH that exceeds an RSRP threshold on a downlink beam (e.g., the current downlink beam) in HD mode. In such examples, UE 115-a may transmit the RACH on the downlink beam using different modes, such as FD RACH and HD RACH, so that network entity 105-a can distinguish between the two types of RACH on the same downlink beam. In some cases, UE 115-a may send different random access opportunities (ROs) or RACH sequences for FD or HD mode. In other cases, UE 115-a may send the same RO and RACH sequence, where the FD and HD modes are indicated in a BFR MAC-CE. In such cases, if UE115-a is to use the same RO and RACH sequence, it may receive an uplink allocation message (e.g., message 2) in HD mode to avoid SI. In some examples, UE 115-a may send a BFR request via the RACH to reduce specification changes to wireless communication system 200. In some cases, network entity 105-a and UE 115-a may reconsider latency when transmitting RACH messages.

[0112] In some specific implementations, UE 115-a may send a BFR indication via sidelink relay UE 115-c. In this example, sidelink relay UE 115-c may use sidelink channel 230 to connect to UE 115-a. In some cases, UE 115-a may wait for a period of time to receive a BFR response and may retransmit the BFR request via sidelink channel 230 if no BFR response is received. In some examples, compared with techniques for similar RACH-based indications of beam failure and other RACH BFR procedures, UE 115-a may use sidelink-assisted BFR request and response indications to reduce latency.

[0113] In some specific implementations, UE 115-a may combine RACH and sidelink methods to indicate a BFR request to network entity 105-a, thereby increasing robustness and reducing latency. In some examples, when the uplink has ultra-reliable low-latency communication (URLLC) traffic and sidelink and RACH transmissions are allowed to stay in the FD mode without switching to the HD mode (e.g., sending a BFR request via RACH and receiving a response via sidelink), using a combination of RACH and sidelink methods may be useful.

[0114] In other aspects, UE 115-a may send a BFR request during an HD uplink time slot. In some cases, UE 115-a may be expected to be configured with a mix of FD and HD time slots (e.g., not all time slots are FD) such that a BFR request can be sent in an upcoming uplink HD time slot. In other aspects, the BFR response from network entity 105-a may be sent on an HD downlink time slot. In some cases, the decision on which time slots to use may be based on the availability or opportunity to transmit a BFR request using the uplink, RACH, HD uplink, or sidelink.

[0115] As described herein, UE 115-a may send a BFR request to sidelink relay UE 115-c via sidelink channel 230 when a beam failure occurs. In some examples, the BFR request may include an indication of whether the beam failure is due to CLI or SI. In some cases, UE 115-a may determine the type of beam failure based on an increase in SI or CLI or a decrease in downlink reference signal received power (RSRP). In some examples, UE 115-a may detect a beam failure and may check an interference value against a threshold to determine the type of beam failure. The threshold may represent a tolerable level of a particular type of interference at the receiver. For example, UE 115-a may check whether the SINR meets the thresholds of downlink RSRP, SI, and CLI measurements and may measure each measurement against one or more maximum thresholds. In some cases, the maximum SI threshold may be defined as being a certain decibel (dB) lower (e.g., -80 dB) than the uplink transmit power or downlink receive power of UE 115-a or a certain dB higher than the background noise level. In some cases, the maximum CLI threshold may be defined as being a certain decibel (dB) lower (e.g., -80 dB) than the reference power or downlink receive power of UE 115-a or a certain dB higher than the background noise level.

[0116] In some specific implementations, UE 115-a may calculate the SINR by dividing the downlink RSRP by the interference (e.g., downlink RSRP / (SI + CLI + noise)), which can be used to indicate a beam failure when the SINR drops below an outage threshold. In some cases, the SINR is less than the outage threshold and UE 115-a may enable a set of checks for each type of interference. In some cases, UE 115-a may determine that the downlink RSRP divided by the maximum SI threshold plus the maximum CLI threshold plus the noise may be less than the outage threshold (e.g., downlink RSRP / (max_SI threshold + max_CLI threshold + N) < outage threshold) and may be declared as a beam failure based on the downlink RSRP. In other cases, UE 115-a may not determine a beam failure based on the downlink RSRP, but rather determine that the SI measurement may be greater than the maximum SI threshold and the CLI measurement may be greater than the maximum CLI threshold (e.g., SI > max_SI threshold and CLI > max_CLI threshold) and may be declared as a beam failure based on SI and CLI. Additionally or alternatively, UE 115-a may determine that the SI measurement may be greater than the maximum SI threshold and the CLI measurement may be less than the maximum CLI threshold (e.g., SI > max_SI threshold and CLI < max_CLI threshold) and may be declared as a beam failure based on SI. In other examples, UE 115-a may determine that the SI measurement is less than the maximum SI threshold and the CLI measurement may be greater than the maximum CLI threshold (e.g., SI < max_SI threshold and CLI > max_CLI threshold) and may be declared as a beam failure based on CLI. In some examples, the beam failure based on SI and CLI, the beam failure based on SI, and the beam failure based on CLI may indicate a new mode of beam failure of network entity 105-a. In some examples, UE 115-a may determine that the beam failure is the result of SI or CLI, and the downlink RSRP may support communication in the HD mode.

[0117] In some specific implementations, UE 115-a may transmit a BFR request to network entity 105-a via sidelink channel 230. In some cases, UE 115-a may detect a beam failure due to SI or CLI and may initiate a BFR request to network entity 105-a. In some examples, UE 115-a may construct a BFR request that may include a BFR MAC-CE, information about the SI or CLI that caused the beam failure, and other routing information. UE 115-a may send the BFR request to network entity 105-a via an appropriate path (e.g., link) selected based on some conditions (e.g., priority rules). In some cases, the path may include sidelink channel 230 that allows sidelink relay UE 115-c to receive the BFR request and Uu link 235 that sends the BFR request to network entity 105-a. In some cases, UE 115-a may monitor the BFR response from network entity 105-a using specific resources and / or links based on a set of rules. UE 115-a may receive the BFR response from network entity 105-a and switch the beam for transmission or undergo further beam management.

[0118] In some examples, UE 115-a may construct a BFR request that includes information about the beam failure caused by SI or CLI and additional routing information. In some cases, UE 115-a may request newly configured measurement resources to monitor SI and CLI for continuous SI or CLI measurements. In some cases, network entity 105-a may configure resources within a beam failure detection reference signal (BFD-RS) to obtain periodic RSRP, SI, and CLI measurements. For example, uplink RS may be configured as an SI interference measurement resource (IMR) (e.g., demodulation reference signal (DMRS), sounding reference signal (SRS)) for UE 115-a to measure SI. In some cases, the resources may be configured to measure SI due to different uplink transmission beams. In other examples, one or more SRS-RSRP or CLI received signal strength indicator (RSSI) resources may be configured as CLI-IMRs to measure CLI at UE 115-a. In some examples, network entity 105-a may configure multiple CLI-IMRs to measure CLI due to different neighboring UEs. Additionally or alternatively, network entity 105-a may configure resources to measure a single CLI-IMR and may measure the total CLI from multiple neighboring UEs. In some cases, periodic CLI-IMRs may be used to measure CLI, which may not consider the interference UE transmission scheduling and may avoid degraded CLI.

[0119] In some aspects, UE 115-a may construct the content of a BFR request to include various types of information that may be beneficial to network entity 105-a. In some examples, the BFR request may include SI or CLI indications. In some cases, the MAC layer may use one or more bits to indicate to network entity 105-a via sidelink relay UE 115-c that the beam failure is caused by increased SI, CLI, or both types of interference. In some cases, UE 115-a may send control signaling including a beam failure indication and a corresponding beam failure cause based on measurements associated with the physical layer. In some cases, UE 115-a may send the corresponding identifier of the SI that caused the beam failure, the identifier of the CLI that caused the beam failure, the uplink beam identifier that caused the SI, the uplink beam identifier that caused the CLI, the TRP identifier associated with the beam failure, the UE identifier, the cell identifier, an indication of a set of preferred beams for preferred beams used for uplink and / or downlink transmission, or a combination of the listed identifiers. In some examples, UE 115-a may measure the downlink RSRP, background interference (e.g., noise), SI, and CLI at each measurement occasion and may determine that the beam failure indication at the physical layer of UE 115-a is satisfied and pass the information to the MAC layer. In some cases, the cause of the beam failure may include a reduced downlink RSRP, increased SI, or increased CLI measurements. Additionally or alternatively, the physical layer may pass the raw measurements to the MAC layer and may determine the cause of the beam failure. In some examples, UE 115-a may determine that all control beams across all transmit receive points (TRP) have failed and may indicate a total beam failure. In other cases, UE 115-a may determine that all control beams on a single TRP have failed and may indicate a per-TRP beam failure.

[0120] In other aspects, UE 115-a may construct the content of the BFR request to include information about interfering beams. In some cases, UE 115-a may report the identity (ID) of the SI-IMR or CLI-IMR that caused the beam failure of network entity 105-a and may identify the interfering uplink beam or the adjacent UE beam. In some examples, network entity 105-a may identify the uplink beam or the adjacent UE beam and undergo a calibration process. In some cases, when UE 115-a has multiple uplink beams (e.g., mTRP uplink beams), UE 115-a may report the SI-IMR. Additionally or alternatively, when the SI-IMR is not configured, UE 115-a may report the uplink beam identity that caused the SI (e.g., the SI is measured on data that may use different uplink transmission beams). In some cases, UE 115-a may report the failed TRP ID for each TRP beam failure, where a single beam has failed between multiple downlink beams. In other cases, UE 115-a may report the failed CLI-IMR for each interfering CLI beam. In some cases, the CLI-IMR may be unconfigured and UE 115-a may reuse the RSRP and SI measurement opportunity (MO) to measure the RSSI of the CLI and report the total CLI level to network entity 105-a. In some cases, network entity 105-a may identify that the beam failure is caused by the CLI, and the interfering UE may not be aware of the CLI. Additionally or alternatively, if the CLI-IMR is unconfigured, in addition to CLI detection, UE 115-a may also report the aggregated CLI to assist network entity 105-a in determining one or more interfering UEs. In other examples, when the CLI-IMR is unconfigured, UE 115-a may report some characteristics of the observed CLI that assist network entity 105-a in finding the interfering UE (e.g., the resource block (RB) range facing the increasing CLI, the root of the detected DMRS / SRS sequence, the detected MCS, etc.).

[0121] In other embodiments, UE 115-a may construct the content of the BFR request to include the increased values of SI or CLI. In some cases, these values may be in absolute units of decibel-milliwatts (dBm), relative units of dB, or quantization units (e.g., low, medium, high), etc. In some cases, UE 115-a may send the increased values of SI or CLI to assist network entity 105-a in adjusting the uplink power and reducing interference.

[0122] In some examples, UE 115-a may construct the content of a BFR request to include information for forwarding to network entity 105-a and a UE identifier. In some cases, UE 115-a may pass a cell ID (e.g., a physical cell ID (PCI)), a serving cell ID, and a UE ID (e.g., a cell radio network temporary identifier (C-RNTI)) in a BFR MAC-CE. In some examples, UE 115-a may pass the cell ID to allow sidelink relay UE 115-c and wireless communication system 200 to pass the BFR request to an appropriate (e.g., destination) network entity. In some cases, for a sidelink relay UE 115-c connected to the same network entity or cell as the UE 115-a that sends the BFR request, the cell ID may not be sent. In other cases, sidelink relay UE 115-c may pass the BFR request to its own network entity 105-a, and network entity 105-a will forward the BFR request to an appropriate network entity via the core network based on the cell ID. In some aspects, if UE 115-a indicates a BFR request via uplink beam 210, UE 115-a may skip reporting the ID of UE 115-a and / or the cell ID of UE 115-a.

[0123] In some examples, sidelink relay UE 115-c may receive a BFR request via sidelink channel 230 and may automatically trigger forwarding the BFR request to network entity 105-a. In some cases, when forwarding the request to an appropriate network entity to track the sidelink path of a BFR response, a first forwarding network entity (e.g., network entity 105-a of sidelink relay UE 115-c) may append the ID of the first forwarding network entity to the BFR request. In other examples, network entity 105-a of sidelink relay UE 115-c may identify that UE 115-a can reach via sidelink relay UE 115-c when delivering a response back to the correct UE 115-a. In some cases, an appropriate network entity may use a routing table to route the response to the first forwarding network entity 105-a, which may then forward the response to sidelink relay UE 115-c and continue to forward it to UE 115-a. In some examples, the design for relaying BFR MAC-CE requests and responses may reuse a design similar to that used for buffer status report (BSR) MAC-CE forwarding in a multi-hop network.

[0124] In some aspects, UE 115-a may construct the requested content to indicate a preferred new beam for downlink, uplink, or both in a BFR request. In some cases, the indication of the new beam may depend on the intelligence of the measurement capabilities of UE 115-a. In some examples, a new candidate downlink beam may be selected based on SINR measurements and a SINR threshold configured by the network. In some cases, UE 115-a may compare different (e.g., measured) metrics with new beam selection thresholds (e.g., RSSI for downlink beam blockage, SINR for SI- or CLI-based BFR) in conjunction with the reason for beam failure. In some cases, UE 115-a may select one or more possible downlink beams that can meet the SINR threshold configured by the network (e.g., a measurement threshold greater than the SINR threshold). In some examples, one or more downlink beams may be designated as one or more preferred beams. Additionally or alternatively, UE 115-a may select one or more downlink beams that maximize a measured metric (e.g., SINR) to select one or more preferred beams. In some examples, the SINR of a new candidate downlink beam may be measured using an ongoing downlink synchronization signal block (SSB), channel state information (CSI) RS, DMRS, uplink SRS or DMRS for SI measurements that may be triggered by BFR, and uplink SRS or DMRS from other UEs for CLI measurements. In some cases, a new candidate uplink beam may be identified by making measurements on the new candidate downlink beam and assuming channel reciprocity. In other cases, a new candidate uplink beam may be identified by measurements of different metrics at the uplink transmission from UE 115-a and at network entity 105-a. Additionally or alternatively, UE 115-a may identify candidate downlink and uplink beams based on UE 115-a storing past measurements and stored fallback pairs.

[0125] In some aspects, UE 115-a can construct the content of a BFR request in a variety of ways to indicate a preferred new beam for downlink, uplink, or both in the BFR request. For example, if a new candidate FD downlink beam is found, UE 115-a can send the new beam ID in the BFR request. In other examples, when the FD downlink beam is not available, UE 115-a can send a beam with an available RSRP that can be recovered in the FD mode by reducing the uplink transmission power and indicating the beam ID (e.g., if beam 0 has an RSRP greater than 30 dB, but the SINR is limited to 20 dB due to SI, while the required SINR = 23 dB, and the beam 0 ID with a 3 dB reduction in UL Tx power can be indicated). In other cases, UE 115-a can indicate the downlink beam ID with good RSRP while ignoring the SINR due to the lack of an FD downlink beam that meets the FD constraints. In such cases, UE 115-a may expect to switch to the HD mode for a temporary duration. In some cases, UE 115-a can reduce the power or stop the uplink transmission within the BFR search space until a BFR response from network entity 105-a is received. In some cases, UE 115-a can recommend to network entity 105-a to reduce the uplink transmission power (e.g., reduce by θ dB) to avoid beam failure.

[0126] In some examples, UE 115-a can construct the content of a BFR request to indicate a list of available sidelink UEs at the time when the BFR request is sent and can be received via the sidelink. In some cases, UE 115-a can determine that the uplink and sidelink communications are working, and can send a request via the uplink, and can receive a response from network entity 105-a via the sidelink channel 230. In such cases, UE 115-a can include the ID of one or more nearby (e.g., connected) sidelink relay UEs in the BFR request. In some examples, the format of the ID for the sidelink relay UE ID can include any UE ID, C-RNTI, or an ID provided by another network entity 105-a. In some cases, in addition to transmitting the response via the downlink beam 215, network entity 105-a can also select one sidelink relay UE from the list of sidelink relay UEs to transmit the response. UE 115-a can monitor one or more sidelink relay UEs from the list for a response from network entity 105-a.

[0127] In some cases, UE 115-a may construct the content of the BFR request to monitor the response from network entity 105-a. In some examples, the response from network entity 105-a may include a BFR response to UE 115-a. In some cases, UE 115-a may recommend to network entity 105-a to send the BFR response via a sidelink or the Uu link. In some examples, UE 115-a may be pre-configured to monitor the Uu link, the sidelink, or both for the BFR response from network entity 105-a based on link latency, the priority of uplink or downlink traffic, or based on preferences requested by UE 115-a. In some examples, UE 115-a may monitor the BFR response from network entity 105-a on the Uu link in multiple ways. In some cases, when a new candidate FD downlink beam is indicated, UE 115-a may monitor DCI on the Uu link on the new candidate FD downlink beam. In other cases, UE 115-a may monitor DCI on the Uu link on the indicated FD downlink beam and may reduce the uplink transmission power by a recommended amount (e.g., reduce by θ dB). In other examples, UE 115-a may monitor DCI on the Uu link on the indicated HD downlink beam and may stop uplink transmission (e.g., stop uplink transmission in the BFR search space). In some aspects, UE 115-a may monitor the BFR response via the sidelink (if configured to do so). In some cases, the sidelink relay UE 115-c may send the BFR response via the sidelink path that conveys the BFR request.

[0128] According to one or more aspects of the present disclosure, the UE 115-a may determine candidate sidelink relay UEs to use based on finding (e.g., discovering) a set of available sidelink relay UEs. In some examples, the network entity 105-a may pre-configure the UE 115-a with a list of available sidelink relay UEs for relaying BFR requests that include BFR MAC-CEs, or the UE 115-a may use a sidelink discovery mode to find available sidelink relay UEs. In both cases, the UE 115-a may query among the available sidelink UEs to determine which sidelink relay has an active uplink and may select one of those UEs for sidelink relay. In some examples, the UE 115-a may determine the reliability of the sidelink relay UE by broadcasting or multicasting a BFR request on the sidelink. The UE 115-a may expect multiple UEs to receive the request and forward the request to additional network entities to prove reliability. In some cases, the UE 115-a may determine whether an existing sidelink relay UE 115-c can be a candidate for sidelink transmission. In some examples, the sidelink relay UEs available for sending BFR requests may meet minimum conditions as described herein.

[0129] In some aspects, UE 115-a may determine whether side-link transmission of a BFR request is superior to other modes. For example, UE 115-a may decide to use the side link for BFR requests as compared to the uplink, SR, RACH, and HD uplink opportunities based on latency, priority of uplink and downlink traffic, and link quality. In some examples, the duration for BFR indication varies for each method. For example, the latency via the side link may include the transmission from UE 115-a to side-link relay UE 115-c via the side link and the uplink transmission to network entity 105-a. In some examples, the latency via SR may include the latency to transmit the SR, the latency to receive DCI in response to the SR with a future uplink allocation, and the latency to transmit the BFR request on that uplink allocation. In other examples, the latency via the uplink may include the uplink transmission from UE 115-a to network entity 105-a. In other cases, the latency via RACH may include the latency to transmit or receive Message 1, Message 2, Message 3, and Message 4. In other examples, the latency via the HD uplink opportunity may include the time to the next available HD uplink opportunity or the periodicity of the configured HD uplink grant. Thus, a comparison of the latency of BFR indication across different modes may show that when uplink beam 210 is operating and an uplink allocation is available, UE 115-a may use the existing uplink allocation to transmit the BFR request. However, in other cases, such as if the uplink is operating but the allocation is not available, or if no uplink allocation is available, then UE 115-a may decide on a BFR request method among different available indication methods based on their indicated latency, link quality, and any impact on ongoing uplink and downlink traffic (e.g., UE 115-a may have to switch to the HD mode while waiting for a response from the network entity, thus interrupting the priority uplink traffic).

[0130] In some examples, when the uplink of UE 115-a is unavailable, UE 115-a may determine whether side-link transmission of a BFR request is superior to RACH or the uplink. In some cases, UE 115-a may use the side link when the RACH latency is high, the RACH fails one or more times, a new PRACH beam is unavailable, or the RACH procedure uses more power or resources than side-link transmission. In other examples, where the uplink is operational and allocated for UE 115-a, the uplink may be superior to other transmission modes. In some cases, a side link may be additionally implemented to provide robustness for BFR requests or a new path for transmitting BFR responses. Additionally or alternatively, if the side-link quality exceeds the uplink quality, UE 115-a may use the side link. In some examples, rules for using a side link to relay a UE instead of RACH to transmit a BFR request are compared when the uplink is unavailable. In some cases, if side-link relay UE 115-c has exceeded certain conditions and can be a candidate side-link relay UE, UE 115-a may utilize side-link relay UE 115-c. In some examples, if the latency or periodicity of the next available side-link-assisted BFR indication is less than the latency or periodicity of the next available RACH opportunity, UE 115-a may use the side link on RACH after beam failure detection. In some cases, the indicated latency (e.g., the latency to transmit a BFR request from UE 115-a to network entity 105-a, and not considering the latency to receive a response) may simply be compared between RACH and side-link-assisted BFR, and it may be determined which method to use to transmit the BFR request. In some cases, the response latency of side-link-assisted BFR (the latency to transmit a BFR response from network entity 105-a to UE 115-a) may be less than the response latency of RACH-assisted BFR, and UE 115-a may monitor the side link for the BFR response. In other cases, the RACH-based BFR procedure may have failed multiple times (e.g., X times, where X can be configured by the network or fixed by a standard). In some examples, RACH failures may occur multiple times due to UE 115-a's inability to decode message 2 DCI when the selected downlink beam suffers a large amount of CLI. In such cases where UE 115-a experiences multiple RACH failures, UE 115-a may indicate BFR via the side link and wait for a BFR response with instructions regarding beam recovery (e.g., switching to a different cell).

[0131] In some examples, when a candidate downlink beam is unavailable (e.g., no SSB beam has an SINR greater than a threshold, but at least one SSB beam has an RSRP greater than a threshold) and thus a PRACH opportunity cannot be determined, UE 115-a may use the sidelink on the RACH after beam failure detection. In such cases, the sidelink can be used to send a BFR request and monitor for a BFR response. In other examples, UE 115-a may use the sidelink on the RACH after beam failure detection because the RACH uses more time, frequency, and power resources compared to sidelink transmissions. In some cases, UE 115-a may seek to conserve power resources due to maximum permissible exposure (MPE), low battery, or UE 115-a may be a low-power UE (e.g., industrial Internet of Things (IIoT)). In some examples, a PRACH sequence can span 6 to 12 symbols and up to 144 resource elements (REs) in FR2 and can exceed the resources required for a BFR request. In such cases, transmitting a BFR request on the sidelink can use fewer time or frequency resources. Additionally or alternatively, UE 115-a may use the sidelink on the RACH due to an increase in the robustness or reliability of the BFR. In some examples, UE 115-a may send critical data that a RACH procedure may not provide (e.g., a video frame and may preferably use both links for BFR to quickly reach network entity 105-a). In some cases, when the RACH selects a new candidate downlink beam with a low SINR (e.g., due to CLI) that has an SINR higher than a threshold, UE 115-a may choose to use the sidelink. In such cases, the sidelink can be additionally used to send a BFR request and indicate the availability of an alternative path (via the sidelink) to receive the BFR response. In some cases, if UE 115-a is connected to a good sidelink relay UE 115-c, the sidelink can be considered available for BFR purposes. In other cases, if UE 115-a can find a candidate sidelink relay UE within a short duration (e.g., Y milliseconds, where Y can be configured by the network or fixed by the standard) through discovery mode or an existing future sidelink grant from network entity 105-a, the sidelink can be considered available for BFR purposes.

[0132] In some aspects, UE 115-a may determine that uplink communication is working and there is an allocation for the uplink, and may use the sidelink, the uplink, or both to transmit a BFR request. In some examples, UE 115-a may determine whether the uplink is working by using periodic spatial RS or downlink path loss RS, and if the uplink is working and is allocated, may send a BFR request on the uplink. In some cases, in addition to transmitting the request via the uplink, UE 115-a may also use the sidelink to relay the BFR request to increase robustness. In some examples, UE 115-a may send an indication (e.g., a minimal indication) via the sidelink to indicate to network entity 105-a that there is an additional sidelink path for receiving a BFR response. In some examples, when it is possible to switch to the FD mode, network entity 105-a may use the sidelink path to transmit additional commands other than DCI on the Uu link (e.g., network entity 105-a may use the sidelink to provide IMR for SI or CLI measurements with uplink beam scanning while signaling a handover to a new candidate downlink beam via the Uu link). In other examples, when UE 115-a only indicates beams with HD capabilities in the BFR request, network entity 105-a may use the sidelink path to configure SI or CLI measurement resources to resume the FD mode. In some cases, network entity 105-a may use the sidelink path to continue emergency downlink data transmission via sidelink relay, which may be useful in an extended reality (XR) gaming scenario. Additionally or alternatively, when the estimated uplink link quality is below a threshold or less than the sidelink relay link quality, UE 115-a may send the BFR via the sidelink. In some cases, the uplink link quality may be measured with multiple metrics (e.g., bandwidth (BW), SINR, priority, latency, etc.). In some examples, the sidelink relay link quality may include the combined link quality of the sidelink and the uplink (e.g., the uplink link between sidelink relay UE 115-c and network entity 105-a). In some cases, the link quality may be measured as the minimum of (SINR1, SINR 2) or the maximum of (latency1, latency2). In some examples, UE 115-a may compare the metrics between the uplink and the sidelink relay paths and determine the best path for sending a BFR request to network entity 105-a.

[0133] In some specific implementations of the present disclosure, UE 115-a may select a suitable sidelink relay UE from a set of sidelink relay UEs for a sidelink-assisted BFR request. In some examples, the selected sidelink relay UE may be connected to UE 115-a. For example, UE 115-a is connected to sidelink relay UE 115-c, and sidelink relay UE 115-c may meet the conditions for being a suitable sidelink relay UE to carry the BFR request. Therefore, sidelink relay UE 115-c may be used preferentially over unconnected suitable sidelink relay UEs.

[0134] As described herein, UE 115-a may check sidelink relay UEs available for carrying the BFR request to network entity 105-a. Network entity 105-a may establish periodic sidelink transmission resources to establish sidelink communication. In some examples, the network may pre-configure resources designated for the sidelink. In some cases, UE 115-a is in a first mode (e.g., network control mode) and network entity 105-a may periodically update the list of provided sidelink relay UEs and resource pool allocations. In other cases, UE 115-a is in a second mode (e.g., sensing mode) and UE 115-a may determine transmission parameters without assistance from network entity 105-a. Accordingly, UE 115-a uses the available resources to send a BFR request to sidelink relay UE 115-c on sidelink channel 230.

[0135] In some specific implementations, sidelink relay UE 115-c receives the BFR MAC-CE and may relay the BFR MAC-CE to network entity 105-a. In some cases, new resources may be available for uplink transmission from UE 115-c to network entity 105-a. In some examples, UE 115-c may send a special physical uplink control channel (PUCCH) BFR SR in uplink Uu link 235 to obtain an uplink grant for relaying the BFR MAC-CE. In some examples, the SR may reuse an existing BFR SR for Uu link 235 to request uplink resources for relaying the BFR MAC-CE from UE 115-a. In other examples, a new type of SR may relay the BFR request via uplink Uu link 235 of UE 115-c to notify network entity 105-a.

[0136] In some examples, UE 115-c may relay BFR MAC-CE and emergency uplink or downlink data transmissions from UE 115-a. In some cases, UE 115-a may request to resume an uplink or downlink data connection to UE 115-c. UE 115-c may send this request to network entity 105-a together with the BFR MAC-CE. In some examples, UE 115-c may indicate to UE 115-a, based on its own determination or based on a response from network entity UE 105-a, that there is sufficient power and resources to support downlink data for UE 115-a. In such cases, if sufficient resources are available, UE 115-c may send an additional indication to UE 115-a that sidelink channel 230 and Uu link 235 may support downlink data from network entity 105-a. Additionally or alternatively, UE 115-a may detect an uplink beam failure and a request to send emergency uplink data. In some cases, UE 115-a may ask UE 115-c whether there are sufficient resources to support the transmission of emergency uplink traffic and BFR MAC-CE. UE 115-c may send this request to network entity 105-a together with the BFR MAC-CE. In such cases, if sufficient resources are available, UE 115-c may send an additional indication to UE 115-a that sidelink channel 230 and Uu link 235 may support downlink data from UE 115-a to network entity 105-a. Thus, if sufficient resources are available, UE 115-c may relay emergency uplink traffic from UE 115-a to network entity 105-a. In some aspects, when the corresponding link is restored, UE 115-a may switch from sending and receiving relayed data to its uplink beam 210 and downlink beam 215, respectively. Thus, even when the wireless communication system 200 experiences a beam failure scenario, these methods for restoring uplink and downlink data connections may maintain the quality of service (QoS) at a high level.

[0137] In some specific implementations of the present disclosure, UE 115-a may successfully send a BFR request to network entity 105-a. In some aspects, network entity 105-a may receive an indication of a beam failure that occurs at UE 115-a due to SI or CLI, and may send a BFR response indicating a beam switching action or training to measure RSRP, CLI, and SI. In some examples, network entity 105-a may send the BFR response via sidelink relay UE 115-c, via new downlink beam 240, or via fallback downlink beam. In some cases, network entity 105-a may indicate that downlink beam 215 and downlink beam 240 have failed (e.g., as a group failure), and UE 115-a may switch to possible downlink receive beam 250, and network entity 105-a may switch to possible downlink transmit beam 245. In some examples, network entity 105-a may send the BFR response directly to UE 115-a via an active downlink (e.g., another active beam, a failed downlink beam in HD mode) or sidelink relay UE 115-c that conveys the BFR request.

[0138] In some cases, the BFR response may be sent via the same sidelink path used to send the BFR request, where the BFR response is sent on communication link 235 to sidelink relay UE 115-c and then on sidelink channel 230 to UE 115-a. In some cases, when the latency of the response via sidelink is less than the latency of the response via DCI on a possible downlink beam or an existing working downlink beam, network entity 105-a may choose to use sidelink relay UE 115-c to send the BFR response. Additionally or alternatively, when there are no candidate downlink beams available to carry message 2 on DCI, network entity 105-a may send the BFR response via sidelink. In other examples, network entity 105-a may determine the likelihood of failure to receive message 2 on DCI (e.g., high SI, candidate downlink beams may fail). In some aspects, network entity 105-a may use sidelink to signal useful actions, such as reducing uplink transmit power or switching to a different uplink transmit beam to assist in receiving message 2. In some cases, for reliability, network entity 105-a may indicate to use sidelink in addition to message 2 on DCI on a candidate downlink beam or a second downlink beam. In some examples, network entity 105-a may indicate to UE 115-a a beam management process (e.g., switching process, scanning process) triggered upon receiving the BFR response via sidelink.

[0139] In other aspects, network entity 105-a may send a BFR response via the sidelink relay UE 115-c that forwards the BFR request. In some cases, network entity 105-a may allocate resource and routing information for the sidelink-assisted BFR response. In some examples, network entity 105-a may configure appropriate downlink and sidelink resources for the sidelink relay UE 115-c. In other examples, network entity 105-a may use a specified sidelink DCI or MAC-CE to deliver the response to the serving cell of the sidelink relay UE 115-c, which may relay the response to the sidelink relay UE 115-c and then to UE 115-a. In some cases, network entity 105-a may send information for UE 115-a (e.g., a new downlink grant on a new or indicated downlink beam, a TCI state update, a new sidelink grant) in the BFR response to be delivered via the sidelink relay UE 115-c. In some aspects, the BFR response may carry a UE ID or a BFR request ID to identify which BFR request network entity 105-a is responding to. In some examples, the identification in the BFR response may be the ID of the uplink grant or sidelink grant that carries the BFR request MAC-CE.

[0140] In some embodiments, network entity 105-a may choose to use a new candidate downlink beam to send the BFR response. In some examples, network entity 105-a may send message 2 (e.g., message 4 for CBRA RACH) on the DCI on the indicated downlink beam, regardless of whether the BFR request is received via the sidelink. In some examples, the DCI may be sent on a special SS (e.g., BFR SS, any SS). In some cases, UE 115-a may send a BFR MAC-CE to the sidelink relay UE 115-c and may reset the receive beam to a new candidate downlink beam for monitoring the SS for the BFR response. Additionally or alternatively, network entity 105-a may use a second downlink beam of UE 115-a. In some examples, network entity 105-a may send the BFR response on the downlink beam of UE 115-a via another active downlink beam (e.g., mTRP scenario), a fallback beam (e.g., a wide beam), or on a failed downlink beam in HD mode. In some cases, the method for sending the BFR response on the downlink beam of UE 115-a may include: using the failed downlink beam but transmitting with additional decoding, or transmitting with the failed downlink beam using a low modulation and coding scheme (MCS). In some aspects, to obtain additional reliability, network entity 105-a may combine different methods for sending the BFR response on the downlink beam.

[0141] In some specific implementations, when UE 115-a has received a BFR response, once the allocated time (e.g., X milliseconds) has passed, UE 115-a may switch the uplink or downlink beam. The beam to be switched can be determined based on the received BFR response. In some examples, UE 115-a may receive a BFR response from network entity 105-a and may switch the uplink or downlink beam on the Uu link to the newly indicated beam after a plurality (e.g., X) of time slots. In some examples, the number of time slots may be pre-configured by a standard specification or indicated in the BFR response. In some cases, once the BFR response is received, UE 115-a may start measuring the elapsed time (e.g., X milliseconds may be pre-configured on the indicated BFR response). In other examples, once the BFR request is sent, UE 115-a may start measuring the elapsed time (e.g., X milliseconds may be pre-configured). In some examples, the uplink and downlink beam switches may be indicated, and the same allocated time may apply to both beam switches.

[0142] Figure 3 An example of a process flow 300 that supports sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure is illustrated. In some examples, process flow 300 may be implemented into wireless communication systems 100 and 200. Process flow 300 may be implemented into a UE and a network entity, and the UE and the network entity may be examples of corresponding devices as described herein (including reference Figure 1 as described).

[0143] In some examples, a UE may send a BFR request to a network entity via a sidelink. In some cases, the UE may expect a sidelink relay UE to send the BFR request to the network entity. In some examples, the UE may search for candidate sidelink relay UEs that meet a minimum set of conditions 315 that will be able to send the BFR request. In some cases, a candidate sidelink relay UE may be accepted when it is part of a list of acceptable sidelink relay UEs, which is constructed by the UE sending the BFRE request or by the network, or that meets the conditions to be marked as an acceptable sidelink relay UE. For example, the UE sending the BFR request may take a set of possible sidelink relay UEs and determine whether each sidelink relay UE meets such conditions as an acceptable sidelink and uplink latency condition 315-a, an acceptable sidelink and uplink link quality condition 315-b, an established sidelink relay mode condition 315-c, and a condition 315-d of being able to reach the serving network entity for the UE sending the BFR request. In some examples, these conditions may apply to the sidelink relay UE when the UE sending the BFR is selecting possible sidelink relay UEs. Additionally or alternatively, the network entity may pre-configure a list of possible sidelink relay UEs.

[0144] In some examples, condition 315-a may check whether the sidelink relay UE meets acceptable sidelink and uplink latency. In some cases, the sidelink relay UE may pass the acceptable sidelink condition if there is access to sidelink and uplink grants with reasonable latency (e.g., relative to another granted latency) or periodicity (e.g., periodicity of a configured grant). In some cases, the latency of the sidelink grant may be less than a threshold of the maximum sidelink latency (e.g., SL < T max-SL ) and the latency of the uplink grant may be less than a threshold of the maximum uplink latency (e.g., UL < T max-UL ), or the sidelink and uplink grant latencies must be less than a total threshold of the maximum sidelink and uplink grant latencies of the sidelink grant and the uplink grant (e.g., SL + UL < T max-SL+UL)To meet acceptable quality. Additionally or alternatively, the sidelink relay UE may notify the UE that sent the BFR request of sidelink and uplink grant availability information for the purpose of latency calculation. The grant availability information may include a portion of sidelink grant configuration information, SR configuration information, CG configuration information, or DG configuration information, where the information applies to both periodic and latency-based criteria. In some examples, the grant availability information may include the periodicity associated with the uplink grant, the slot offset associated with the uplink grant, the latency between two uplink grants (e.g., the latency to the next grant), the time and frequency resources per grant occasion, the physical layer uplink priority of the data to be transmitted in the uplink grant (e.g., high, low). In some cases, the arrival time of the next available SR or uplink grant occasion for the sidelink relay UE is signaled, and the arrival time may be less than a specific threshold for latency-based decisions. In some examples, the threshold may be related to the RACH periodicity of the UE that sent the BFR request. In some cases, the threshold is important for ensuring that the BFR indication is transmitted via the sidelink faster than using the RACH procedure.

[0145] In some specific implementations of the present disclosure, condition 315-a may check whether the sidelink relay UE meets acceptable sidelink and uplink latency. In some cases, the sidelink relay UE may convey acceptable latency conditions to be accepted as a sidelink relay UE capable of carrying a BFR request. In some aspects, the latency value may be approximate or exact. In some cases, an approximate latency may be calculated based on the SR periodicity of the BFR UE. In such cases, the SR periodicity may be shared across multiple UEs. In other examples, an exact latency may be allocated after communicating with the sidelink relay UE or listening to broadcast messages on the sidelink channel. In some examples, the sidelink relay UE may indicate that some SRs or uplink grants are not available for sending BFR requests (e.g., due to emergency uplink traffic at the sidelink relay UE). In some examples, the sidelink relay UE may suppress sending the BFR indication because of a lack of processing time to relay the indication, and the sidelink relay UE may be set to wait for a certain amount of time (e.g., X milliseconds) before transmitting the next available sidelink grant. In other examples, some SRs and uplink grants available at the sidelink relay UE may not be available for sending BFR indications. Additionally or alternatively, some SRs and uplink grants may not be able to send BFR indications due to priority reasons, where lower-priority SRs or uplink grants may be cancelled by the sidelink relay UE.

[0146] In some aspects, condition 315-b may check whether the sidelink relay UE meets acceptable sidelink and uplink link quality. In some examples, the uplink quality of the sidelink relay UE may meet the acceptable link quality (e.g., X dB SINR, X megabits per second (Mbps) throughput, etc.), and the sidelink of the sidelink relay UE may have acceptable link quality. In some cases, the sidelink relay UE may broadcast or unicast the downlink quality or the estimated uplink quality for each cell ID or network entity ID. In some examples, the RSRP of the sidelink RS may be used by the UE that sends the BFR request to evaluate the sidelink quality of the sidelink relay UE. In some examples, the basis for the acceptable link quality may use a threshold defined for the UE or by the UE that sends the BFR request.

[0147] In other cases, condition 315-c may check whether the sidelink relay UE is established in the relay mode. In some cases, the sidelink UE may be established in the relay mode. In some examples, the sidelink relay UE may declare the sidelink relay capability by periodically sending an indicator (e.g., within the discovery message) on a periodic channel or by a message (e.g., L1, L2, or L3 message) transmitted via a common broadcast channel or a dedicated channel as a one-time indicator. In some cases, the sidelink UE may also declare in the sent indicator whether it can relay data, MAC-CE, or both.

[0148] In some aspects, condition 315-d may check whether the sidelink relay UE can reach the expected network entity to which the UE sends the BFR request. In some examples, the sidelink relay UE may use the UE that sends the BFR request to send the identifiers of the possible nodes to communicate with. In some cases, the sidelink relay UE may list the IDs for at least one distributed unit (DU) ID, TRP ID (e.g., coresetPool index), cell ID (e.g., physical cell ID (PCI)), or network entity ID (e.g., gNB ID).

[0149] Additionally or alternatively, candidate sidelink relay UEs that can send BFR requests to the network entity may be evaluated for some additional conditions. For example, the sidelink relay UE may establish sidelink BFR MAC-CE logical channel priorities for the sidelink and the Uu uplink. In some cases, the channel priorities may determine how the uplink logical channels available for the sidelink relay UE handle the BFR requests. In some examples, the priorities of the BFR MAC-CE may be defined by the standard, or the sidelink relay UE may indicate the priorities.

[0150] In other cases, candidate sidelink relay UEs for sending a BFR request to a network entity can be evaluated against a set of conditions for receiving a BFR response from the network entity. In some examples, when a BFR response is sent via the sidelink of the UE that sends the BFR request, the conditions described herein for sending a BFR request via the sidelink can still apply to the candidate sidelink relay UE. However, in some cases, the candidate sidelink relay UE may miss some of the conditions for sending the BFR response. In some aspects, the network entity can be flexible and can provide a downlink or sidelink allocation to meet these conditions. In some examples, the network entity can use the same sidelink as the UE that sends the BFR request to indicate the BFR response, or can provide the downlink or sidelink configuration required to communicate with the UE that sends the BFR. In other examples, the network entity can configure an additional (e.g., new) sidelink relay UE or use an existing downlink connection to send the BFR response.

[0151] In some aspects, the UE that sends the BFR request can be based on a connection to a sidelink UE with an acceptable latency (e.g., a latency that meets a threshold). In some cases, in a first mode, the UE that sends the BFR request can access a sidelink grant configured by network entity 105-a. In other cases, in a second mode, the UE that sends the BFR request can have the ability to sense and allocate sidelink resources without the assistance of network entity 105-a. In some cases, if the UE that sends the BFR request has a sidelink grant with a period less than T max (in milliseconds), it can send the BFR request via the sidelink (e.g., the UE can connect to the sidelink when the latency value < T max . In some examples, T max is network-configured and can depend on (e.g., be equal to) the RACH configuration period. Additionally or alternatively, the UE that sends the BFR request may not have a sidelink grant with a period less than T max (in milliseconds), and the sidelink may not be considered available for BFR purposes, and the UE sends the BFR request via other methods such as RACH, SR, an existing uplink allocation, or an HD uplink opportunity. Additionally or alternatively, the network can change the latency rule to determine the availability of the sidelink and can instead delay in milliseconds to the next sidelink opportunity less than T max (e.g., the UE should be able to connect to the sidelink UE at the next sidelink opportunity < T max to make the latency condition more specific.

[0152] In some aspects of the present disclosure, a UE may determine to send a BFR request via a sidelink based on certain conditions. For example, the UE sending the BFR request may evaluate a set of multiple candidate sidelink relays under certain conditions. For example, condition 305 may determine whether one of the set of multiple candidate sidelink relays can be connected to the sidelink with a latency less than a threshold. Additionally or alternatively, condition 310 may determine whether one of the set of multiple candidate sidelink relays meets a minimum condition 315 and is acceptable for relaying the BFR request. In some cases, a candidate sidelink relay UE may pass both condition 305 (at 320) and condition 310, and an approval 325 may indicate that the candidate sidelink relay UE can be used to send the BFR request to a network entity. In other cases, the candidate sidelink relay UE may not pass both condition 305 and condition 310, and a non-approval 330 may indicate that the candidate sidelink relay UE cannot be used to send the BFR request to a network entity.

[0153] Figure 4 An example of a wireless communication system 400 that supports sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure is illustrated. In some examples, the wireless communication system 400 may implement aspects of the wireless communication systems 100 and 200. The wireless communication system 400 may include a UE 115-d, a network entity 105-b, and a network entity 105-c, which may be examples of corresponding devices as described herein (including with reference to Figure 1 and Figure 2 described). In some examples, the network entity 105-b may use a downlink channel 405 for one or more downlink beams to the UE 115-d, and may use an uplink channel 430 for one or more uplink beams to the network entity 105-c.

[0154] In some aspects, a network entity may send a BFR response to a UE that includes an indication to change a downlink beam to avoid high SI or CLI situations in a particular direction. In some examples, network entity 105-a may switch to the HD mode, maintain high-priority traffic, and discard other traffic, or reduce the uplink transmission power in cases where a high SI response may be experienced. In some cases, network entity 105-a may indicate a change of the uplink transmission beam to a fallback uplink beam 425 with low SI, or trigger a new uplink transmission beam selection with SI measurement. In other examples, network entity 105-a may reduce the uplink transmission power that interferes with the UE, switch to a fallback uplink beam that interferes with the UE, trigger a new uplink beam selection for the interfering UE with CLI measurement, or trigger a sidelink-assisted low-overhead beam selection for the UE that sent the BFR request and for the interfering UE. In some examples, the UE that sent the BFR request may decide on a sidelink-assisted low-overhead beam selection for the interfering UE based on sidelink discovery.

[0155] In some specific implementations of the present disclosure, the BFR response from a network entity may depend on the cause of the beam failure. In some examples, the BFR response from a network entity may indicate a change of the downlink beam at the UE that sent the BFR request to avoid high SI or CLI directions. In some cases, the downlink beam may be changed for any reason of the beam failure, such as downlink blockage, SI, or CLI. In some examples, the UE may receive an indication of a new downlink beam, which may be the preferred downlink beam of the UE indicated in its BFR request or a different downlink beam.

[0156] In wireless communication system 400, UE 115-d may indicate in its BFR request that the beam failure is caused by SI. In some examples, network entity 105-b may command UE 115-d to switch to the HD mode. In some cases, the HD mode may be duplex in time or frequency (e.g., full, partial, or non-overlapping). In such cases, UE 115-d may use some fallback resource allocation for the HD mode, or may be provided with resource allocation from network entity 105-b for the HD mode. In some examples, one or more uplink and downlink transmissions at UE 115-d may be discarded based on priority traffic (e.g., URLLC is prioritized over eMBB traffic).

[0157] In some examples, the beam failure at UE 115-d can be caused by SI 420. In some examples, network entity 105-b can command UE 115-d to reduce the power in uplink beam 410 that may cause interference 420 to downlink beam 415. In some examples, UE 115-d can request how much uplink transmit power reduction is needed for downlink beam 415 and uplink beam 410 to function under FD. In some cases, UE 115-d can receive a BFR response from network entity 105-b via the downlink, and the BFR response indicates a fallback uplink beam 425 that has low SI relative to the failed downlink beam 415 and is switched from uplink beam 410. In some cases, even with the fallback beam 425, UE 115-d may measure high SI and may fallback to the HD mode or cancel the uplink transmission. In some examples, UE 115-d can receive an indication of a new uplink beam and can change its uplink beam to the indicated uplink beam. The indicated uplink beam in this case can be the preferred uplink beam indicated by UE 115-d in its BFR request or a different uplink beam.

[0158] In some aspects, the beam failure at UE 115-d can be caused by SI 420. In some examples, network entity 105-d can trigger an SI measurement process at UE 115-d, and the SI measurement process can scan the uplink, downlink, or both beams. In some cases, a report of the number (e.g., K) of beams or beam pairs with interference below the interference threshold can be transmitted to UE 115-d via the uplink or sidelink. In some cases, network entity 105-c can also select a beam or beam pair from the beams or beam pairs reported by UE to optimize the downlink or uplink SINR. In some cases, the optimization is performed, and UE 115-d can be indicated of the selected uplink or the selected uplink and downlink pair.

[0159] In some examples, UE 115-d may indicate a beam failure of an uplink beam that may have been caused by CLI. In some cases, a network entity may communicate with the interfering UE (e.g., the source of the CLI) and request to reduce the power in its interfering uplink beam or switch the interfering uplink beam to a different or fallback uplink beam with low CLI. In some cases, the interfering UE may switch to a more favorable uplink beam, and UE 115-d may retry the uplink transmission with the failed downlink beam. In some examples, even after the network entity signals that it has responded to the beam failure request, UE 115-d may measure high CLI. In such cases, UE 115-d may fallback to the HD mode or cancel the uplink transmission. In some cases, the method may be applicable to the flexible TDD mode, where neighboring cells have different communication directions simultaneously (e.g., downlink in the first cell and uplink in the second cell).

[0160] In some embodiments, UE 115-d may indicate a beam failure of an uplink beam that may have been caused by CLI. In some cases, the network entity may indicate a CLI measurement routine, where the interfering UE may transmit an uplink RS and scan the uplink beam. In some cases, UE 115-d may measure CLI on the configured CLI measurement resources. In some examples, the network entity may perform a beam scan for UE 115-d to make measurements on multiple downlink beams. In some cases, UE 115-d may collect a report including the number (e.g., K) of beams or beam pairs that may satisfy the CLI threshold at UE 115-d, and may send the report to the network entity via the uplink or sidelink. In some examples, the interfering UE may measure the SINR on one or more downlink beams during its uplink RS transmission. In some cases, the interfering UE may collect a report including the number (e.g., M) of beams or beam pairs that may satisfy the SINR threshold. In some examples, the network entity may also select a beam or beam pair from the reported beams or beam pairs to optimize the downlink beam that has failed at the UE or the uplink of the interfering UE. In some cases, the network entity signals the selected uplink beam or the downlink and uplink beam pair to the interfering UE via the downlink. Additionally or alternatively, the network entity may signal a new uplink beam or the downlink and uplink beam pair to UE 115-d. In some cases, the method is applicable to the flexible TDD mode where neighboring cells have different communication directions simultaneously (e.g., downlink in the first cell and uplink in the second cell).

[0161] In some examples, the network entity may identify that UE 115-d and the interfering UE are in the same cell, or the interfering UE is a sidelink relay UE. In some cases, UE 115-d may communicate with the interfering UE via the sidelink. In some examples, the network entity may configure the two UEs to perform sidelink-assisted low-overhead beam selection. In some cases, the interfering UE may scan a set of uplink beams, and UE 115-d may send a report of the measured CLI to the interfering UE via the sidelink, as a set of the measured CLI, the measured SINR, or (e.g., K) the best measured beams. Additionally or alternatively, UE 115-d may scan downlink beams to measure the CLI. In some cases, an intelligent beam scanning algorithm may be implemented between the interfering UE and UE 115-d, which may achieve faster beam selection via an iterative process of updating uplink and downlink beams using sidelink-based signaling. In some examples, the intelligent beam scanning algorithm may be machine learning-based or include beams based on sparse reconstruction. In some examples, a report of the number of uplink beams of the interfering UE (e.g., K), or the number of downlink beams of UE 115-d (e.g., K), or the number of beam pairs of uplink and downlink beams that may satisfy a CLI threshold (e.g., K) is sent to the network entity via the uplink of UE 115-d or the uplink of the interfering UE. In some aspects, the network entity signals the appropriate uplink and downlink beam pairs for the two UEs based on the optimization of the joint uplink SINR and downlink SINR at the two UEs. In some cases, the method is applicable to the flexible TDD mode.

[0162] Figure 5 An example of a process flow 500 that supports sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure is illustrated. In some examples, process flow 500 may implement aspects of wireless communication systems 100, 200, and 400. Process flow 500 may include UE 115-e and network entity 105-d, which may be examples of corresponding devices as described herein (including reference Figures 1 to 4 as described).

[0163] At 505, network entity 105-d may send an indication of one or more resources associated with a set of multiple BFD-RSs. In some examples, network entity 105-d may indicate the configured resources within the BFD-RS to UE 115-e. At 510, network entity 105-d may periodically send RSRP measurements, SI measurements, and CLI measurements based on the resources associated with the multiple BFD-RSs.

[0164] At 515, UE 115-e may identify a beam failure of one or more communication beams at UE 115-e. In some examples, the beam failure is associated with an interference type such as RSRP, SI, or CLI, and the beam failure of the uplink beam or the downlink beam may be identified for UE 115-e.

[0165] At 520, UE 115-e may send a BFR request to network entity 105-d. In some cases, UE 115-e may determine to send the BFR request using an available sidelink relay UE based on the sidelink relay UE satisfying a threshold. The sidelink relay UE may be approved for relaying the BFR request, and UE 115-e may send the BFR request to network entity 105-d via a sidelink channel. In some cases, the BFR request includes transmission control signaling, which includes: an indication of increased SI, an indication of increased CLI, an identifier of SI that causes the beam failure, an identifier of CLI that causes the beam failure, an uplink beam identifier of SI, a TRP identifier associated with the beam failure, a UE identifier, a cell identifier, an indication of a set of preferred beams for the downlink or uplink or both, or a combination of indicators.

[0166] At 525, network entity 105-d receives the BFR request including whether the beam failure at UE 115-e is associated with SI or CLI, and identifies possible beam switching parameters based on the BFR request. In some cases, the beam switching parameters may identify possible candidate beams for communication between UE 115-e and network entity 105-d.

[0167] At 530, network entity 105-d may send a BFR response including one or more beam switching parameters based on the BFR request. In some examples, the BFR response may indicate a change in the uplink beam or the downlink beam of UE 115-e based on the type of beam failure. In some cases, the BFR response may include a request for UE 115-e to switch from the FD mode to the HD mode. UE 115-e may receive the BFR response and initiate a beam training process using RSRP measurement resources, SI measurement resources, and CLI measurement resources to establish a second communication beam to network entity 105-d.

[0168] Figure 6FIG. 600 is a block diagram of a device 605 that supports sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure. The device 605 may be an example of aspects of the UE 115 as described herein. The device 605 may include a receiver 610, a transmitter 615, and a communication manager 620. The device 605 may also include a processor. Each of these components may communicate with one another (e.g., via one or more buses).

[0169] The receiver 610 may provide components for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to sidelink-assisted indication of beam failure). The information may be passed to other components of the device 605. The receiver 610 may utilize a single antenna or an array of multiple antennas.

[0170] The transmitter 615 may provide components for transmitting signals generated by other components of the device 605. For example, the transmitter 615 may transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to sidelink-assisted indication of beam failure). In some examples, the transmitter 615 may be co-located with the receiver 610 in a transceiver module. The transmitter 615 may utilize a single antenna or an array of multiple antennas.

[0171] The communication manager 620, the receiver 610, the transmitter 615, or various combinations thereof or their various components may be examples of components for performing various aspects of sidelink-assisted indication of beam failure as described herein. For example, the communication manager 620, the receiver 610, the transmitter 615, or various combinations thereof or components may support methods for performing one or more of the functions described herein.

[0172] In some examples, the communication manager 620, the receiver 610, the transmitter 615, or various combinations thereof or components may be implemented in hardware (e.g., in a communication management circuit). The hardware may include a processor, a digital signal processor (DSP), a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, a microcontroller, discrete gate or transistor logic, discrete hardware components, or any combination thereof configured to or otherwise supporting components for performing the functions described in the present disclosure. In some examples, the processor and the memory coupled to the processor may be configured to perform one or more of the functions described herein (e.g., by the processor executing instructions stored in the memory).

[0173] Additionally or alternatively, in some examples, the communication manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof may be implemented in code executed by a processor (e.g., implemented as communication management software or firmware). If implemented in code executed by a processor, the functions of the communication manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof may be performed by a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, a microcontroller, or any combination of these or other programmable logic devices (e.g., components configured or otherwise supporting the performance of the functions described in this disclosure).

[0174] In some examples, the communication manager 620 may be configured to perform various operations (e.g., receive, obtain, monitor, output, transmit) using or otherwise in cooperation with the receiver 610, the transmitter 615, or both. For example, the communication manager 620 may receive information from the receiver 610, convey information to the transmitter 615, or integrate in combination with the receiver 610, the transmitter 615, or both to obtain information, output information, or perform various other operations as described herein.

[0175] According to examples disclosed herein, the communication manager 620 may support wireless communication at the UE. For example, the communication manager 620 may be configured or otherwise support components for identifying a beam failure of at least one communication beam at the UE. The communication manager 620 may be configured or otherwise support components for transmitting a beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference to a network entity via a sidelink channel. The communication manager 620 may be configured or otherwise support components for receiving a beam failure recovery response indicating one or more beam switching parameters based on the beam failure recovery request, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference.

[0176] By including or configuring a communication manager 620 according to examples described herein, the device 605 (e.g., a processor controlling the receiver 610, the transmitter 615, the communication manager 620, or combinations thereof or otherwise coupled thereto) may support techniques for reducing processing, reducing power consumption, and more efficiently utilizing communication resources.

[0177] Figure 7FIG. 700 is a block diagram of a device 705 that supports side - link assisted indication of beam failure in accordance with one or more aspects of the present disclosure. The device 705 may be an example of aspects of device 605 or UE 115 as described herein. The device 705 may include a receiver 710, a transmitter 715, and a communication manager 720. The device 705 may also include a processor. Each of these components may communicate with one another (e.g., via one or more buses).

[0178] The receiver 710 may provide components for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to side - link assisted indication of beam failure). The information may be passed to other components of the device 705. The receiver 710 may utilize a single antenna or an array of multiple antennas.

[0179] The transmitter 715 may provide components for transmitting signals generated by other components of the device 705. For example, the transmitter 715 may transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to side - link assisted indication of beam failure). In some examples, the transmitter 715 may be co - located with the receiver 710 in a transceiver module. The transmitter 715 may utilize a single antenna or an array of multiple antennas.

[0180] The device 705 or its various components may be examples of components for performing various aspects of side - link assisted indication of beam failure as described herein. For example, the communication manager 720 may include a beam failure component 725, a BFR request component 730, a BFR response component 735, or any combination thereof. The communication manager 720 may be an example of aspects of the communication manager 620 as described herein. In some examples, the communication manager 720 or its various components may be configured to use or otherwise cooperate with the receiver 710, the transmitter 715, or both to perform various operations (e.g., receive, obtain, monitor, output, transmit). For example, the communication manager 720 may receive information from the receiver 710, convey information to the transmitter 715, or integrate with the receiver 710, the transmitter 715, or both to obtain information, output information, or perform various other operations as described herein.

[0181] According to examples as disclosed herein, communication manager 720 may support wireless communication at a UE. A beam failure component 725 may be configured to or otherwise support components for identifying a beam failure of at least one communication beam at the UE. A BFR request component 730 may be configured to or otherwise support components for sending, via a sidelink channel, a beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference to a network entity. A BFR response component 735 may be configured to or otherwise support components for receiving, based on the beam failure recovery request, a beam failure recovery response indicating one or more beam switching parameters, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference.

[0182] Figure 8 Block diagram 800 illustrates a communication manager 820 supporting sidelink-assisted indication of a beam failure, in accordance with one or more aspects of the present disclosure. Communication manager 820 may be an example of aspects of communication manager 620, communication manager 720, or both as described herein. Communication manager 820 or its various components may be examples of components for performing various aspects of the sidelink-assisted indication of a beam failure as described herein. For example, communication manager 820 may include a beam failure component 825, a BFR request component 830, a BFR response component 835, a resource indication component 840, a measurement component 845, a UE identification component 850, a UE selection component 855, a UE indication component 860, a UE signaling component 865, a UE capability component 870, a UE identifier component 875, a beam training component 880, a beam identification component 885, a beam indication component 890, a threshold component 895, a RACH configuration component 8100, a signal interference component 8105, a mode switching component 8110, or any combination thereof. Each of these components may communicate directly or indirectly with each other (e.g., via one or more buses).

[0183] According to examples as disclosed herein, communication manager 820 may support wireless communication at a UE. A beam failure component 825 may be configured to or otherwise support components for identifying a beam failure of at least one communication beam at the UE. A BFR request component 830 may be configured to or otherwise support components for sending, via a sidelink channel, a beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference to a network entity. A BFR response component 835 may be configured to or otherwise support components for receiving, based on the beam failure recovery request, a beam failure recovery response indicating one or more beam switching parameters, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference.

[0184] In some examples, the resource indication component 840 may be configured to or otherwise support a component for receiving an indication of one or more resources associated with a set of multiple beam failure detection reference signals from a network entity. In some examples, the measurement component 845 may be configured to or otherwise support a component for periodically obtaining at least one of a reference signal received power measurement, a self-interference measurement, and a cross-link interference measurement based on one or more resources.

[0185] In some examples, to support sending a beam failure recovery request, the BFR request component 830 may be configured to or otherwise support a component for sending control signaling that includes at least one of the following: an indication of increased self-interference, an indication of increased cross-link interference, an identifier of self-interference that causes a beam failure, an identifier of cross-link interference that causes a beam failure, a cross-link interference beam indication that causes cross-link interference, an uplink beam identifier that causes self-interference, a transmit-receive point identifier associated with the beam failure, a UE identifier, a cell identifier, an indication of a set of preferred beams for downlink or uplink or both, or a combination thereof.

[0186] In some examples, the UE identification component 850 may be configured to or otherwise support a component for identifying a set of multiple sidelink relay UEs for sending a beam failure recovery request. In some examples, the UE selection component 855 may be configured to or otherwise support a component for selecting a sidelink relay UE from the set of multiple sidelink relay UEs for sending a beam failure recovery request based on the following: determining that the UE can connect to the sidelink relay UE using a latency value that meets a threshold latency value.

[0187] In some examples, the threshold component 895 may be configured to or otherwise support a component for identifying a set of multiple sidelink relay UEs for sending a beam failure recovery request based on each sidelink relay UE among the multiple sidelink relay UEs being associated with at least one of the following: a threshold sidelink latency, a threshold uplink latency, a threshold sidelink link quality, a threshold uplink link quality, a sidelink relay mode setting parameter, the connectivity between each sidelink relay UE and a network entity, the connectivity between each sidelink relay UE and a second network entity, or a combination thereof.

[0188] In some examples, to support sending a beam failure recovery request, the BFR request component 830 may be configured to or otherwise support a component for sending a beam failure recovery request to a sidelink relay UE in a set of multiple sidelink relay UEs based on one or more conditions.

[0189] In some examples, the RACH configuration component 8100 may be configured to or otherwise support a component for receiving an indication of a threshold latency value from a network entity, where the threshold latency value is based on the random access channel configuration periodicity.

[0190] In some examples, the UE is capable of connecting to a sidelink relay UE using a sidelink grant or sensed sidelink resources.

[0191] In some examples, the UE indication component 860 may be configured to or otherwise support a component for receiving an indication of at least one of the following from a sidelink relay UE: uplink grant availability at the sidelink relay UE, periodicity associated with the uplink grant, offset associated with the uplink grant, latency between two uplink grants, time and frequency resources per occasion, physical layer uplink priority, or a combination thereof, where the uplink grant availability is based on scheduling request information, configured grant information, dynamic grant information.

[0192] In some examples, the UE signaling component 865 may be configured to or otherwise support a component for the following actions: receiving signaling from a sidelink relay UE indicating the downlink quality or estimated uplink quality or both associated with each cell identifier or network entity identifier associated with the sidelink relay UE, where the signaling includes broadcast signaling or unicast signaling.

[0193] In some examples, the UE capability component 870 may be configured to or otherwise support a component for the following actions: receiving an indicator from a sidelink relay UE indicating the relay capability of the sidelink relay UE, where the indicator is received periodically or periodically.

[0194] In some examples, the UE identifier component 875 may be configured to or otherwise support a component for the following actions: receiving at least one of a distributed unit identifier, a transmit receive point identifier, a cell identifier, a network entity identifier, or a combination thereof from a sidelink relay UE.

[0195] In some examples, to support receiving a beam failure recovery response, the BFR response component 835 may be configured to or otherwise support a component for the following actions: receiving a beam failure recovery response that indicates a change in the UE's uplink beam or downlink beam based on whether the beam failure is associated with self-interference or cross-link interference.

[0196] In some examples, to support receiving a beam failure recovery response, the BFR response component 835 may be configured to or otherwise support components for the following actions: receiving a beam failure recovery response that includes a request for the UE to switch from a full-duplex mode to a half-duplex mode.

[0197] In some examples, to support receiving a beam failure recovery response, the BFR response component 835 may be configured to or otherwise support components for the following actions: receiving a beam failure recovery response that initiates a beam training process using at least one of a reference signal received power measurement resource, a self-interference measurement resource, and a cross-link interference measurement resource. In some examples, to support receiving a beam failure recovery response, the beam training component 880 may be configured to or otherwise support components for the following actions: performing a beam training process to establish a second communication beam.

[0198] In some examples, to support receiving a beam failure recovery response, the BFR response component 835 may be configured to or otherwise support components for the following actions: receiving a beam failure recovery response that includes a command to reduce the power associated with an uplink beam at the UE, where the beam failure recovery response is based on the beam failure being associated with self-interference.

[0199] In some examples, to support receiving a beam failure recovery response, the BFR response component 835 may be configured to or otherwise support components for the following actions: receiving a beam failure recovery response that includes a command for the UE to switch a first uplink beam to a second uplink beam, where the first uplink beam has greater signal interference with at least one communication beam than the second uplink beam, and where the beam failure recovery response is based on the beam failure being associated with self-interference.

[0200] In some examples, the signal interference component 8105 may be configured to or otherwise support components for the following actions: determining that the signal interference between a second uplink beam and at least one communication beam is greater than a threshold. In some examples, the mode switching component 8110 may be configured to or otherwise support components for the following actions: switching from a full-duplex mode to a half-duplex mode or canceling an uplink transmission based on the signal interference being greater than the threshold.

[0201] In some examples, to support receiving a beam failure recovery response, the BFR response component 835 may be configured to or otherwise support components for the following actions: receiving a beam failure recovery response that includes a trigger to initiate a process of uplink beam selection with signal interference measurement, where the beam failure recovery response is based on the beam failure being associated with cross-link interference.

[0202] In some examples, the BFR request component 830 may be configured to or otherwise support components for the following actions: sending a set of intermediate cross-link interference reports to a second UE associated with cross-link interference based on identifying a beam failure. In some examples, the beam identification component 885 may be configured to or otherwise support components for the following actions: identifying a set of beams that meet a cross-link interference threshold based on sending the set of intermediate cross-link interference reports. In some examples, the beam indication component 890 may be configured to or otherwise support components for the following actions: sending an indication of the set of beams that meet the cross-link interference threshold.

[0203] In some examples, the indication of the set of beams that meet the cross-link interference threshold is sent from the UE to a network entity or via a second UE to a network entity.

[0204] Figure 9 A diagram of a system 900 including a device 905 that supports sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure is shown. The device 905 may be an example of the device 605, the device 705, or the UE 115 as described herein, or include components thereof. The device 905 may communicate with one or more network entities 105, one or more UEs 115, or any combination thereof (e.g., wirelessly). The device 905 may include components for two-way voice and data communication, which include components for sending and receiving communications, such as a communication manager 920, an input / output (I / O) controller 910, a transceiver 915, an antenna 925, a memory 930, code 935, and a processor 940. These components may be electronically communicated or otherwise (e.g., operatively, communicatively, functionally, electronically, electrically) coupled via one or more buses (e.g., bus 945).

[0205] The I / O controller 910 may manage input signals and output signals of the device 905. The I / O controller 910 may also manage peripheral devices not integrated into the device 905. In some cases, the I / O controller 910 may represent a physical connection or port to an external peripheral device. In some cases, the I / O controller 910 may utilize an operating system, such as or another known operating system. Additionally or alternatively, I / O controller 910 may represent, or interact with, a modem, keyboard, mouse, touch screen, or similar device. In some cases, I / O controller 910 may be implemented as part of a processor (such as processor 940). In some cases, a user may interact with device 905 via I / O controller 910 or via a hardware component controlled by I / O controller 910.

[0206] In some cases, device 905 may include a single antenna 925. However, in some other cases, device 905 may have more than one antenna 925, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. Transceiver 915 may communicate bidirectionally via one or more antennas 925, wired or wireless links as described herein. For example, transceiver 915 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. Transceiver 915 may also include a modem that is configured to: modulate a packet; provide the modulated packet to one or more antennas 925 for transmission; and demodulate a packet received from one or more antennas 925. Transceiver 915, or transceiver 915 and one or more antennas 925, may be examples of transmitter 615, transmitter 715, receiver 610, receiver 710, or any combination thereof or their components as described herein.

[0207] Memory 930 may include random access memory (RAM) and read only memory (ROM). Memory 930 may store computer-readable, computer-executable code 935 that includes instructions that, when executed by processor 940, cause device 905 to perform the various functions described herein. Code 935 may be stored on a non-transitory computer-readable medium (such as system memory or another type of memory). In some cases, code 935 may not be directly executable by processor 940 but may (e.g., when compiled and executed) cause a computer to perform the functions described herein. In some cases, memory 930 may specifically include a basic input / output system (BIOS) that may control basic hardware or software operations, such as interactions with peripheral components or devices.

[0208] Processor 940 may include intelligent hardware devices (e.g., general-purpose processor, DSP, CPU, microcontroller, ASIC, FPGA, programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, processor 940 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into processor 940. Processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 930) to cause device 905 to perform various functions (e.g., functions or tasks supporting sidelink-assisted indication of beam failure). For example, device 905 or components of device 905 may include processor 940 and memory 930 coupled to or coupled with processor 940, and processor 940 and memory 930 are configured to perform the various functions described herein.

[0209] According to an example as disclosed herein, communication manager 920 may support wireless communication at a UE. For example, communication manager 920 may be configured to or otherwise support components for identifying a beam failure of at least one communication beam at the UE. Communication manager 920 may be configured to or otherwise support components for sending a beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference to a network entity via a sidelink channel. Communication manager 920 may be configured to or otherwise support components for receiving a beam failure recovery response indicating one or more beam switching parameters based on the beam failure recovery request, where the beam failure recovery request includes an indication of whether the beam failure is associated with self-interference or cross-link interference.

[0210] By including or configuring communication manager 920 according to an example as described herein, device 905 may support techniques for improving communication reliability, reducing latency, improving the user experience associated with reduced processing, reducing power consumption, more efficiently utilizing communication resources, and improving coordination between devices.

[0211] In some examples, the communication manager 920 may be configured to perform various operations (e.g., receive, monitor, transmit) using or otherwise in cooperation with the transceiver 915, one or more antennas 925, or any combination thereof. Although the communication manager 920 is illustrated as a separate component, in some examples, one or more of the functions described with reference to the communication manager 920 may be supported or performed by the processor 940, the memory 930, the code 935, or any combination thereof. For example, the code 935 may include instructions executable by the processor 940 to cause the device 905 to perform various aspects of the sidelink-assisted indication of beam failure as described herein, or the processor 940 and the memory 930 may otherwise be configured to perform or support such operations.

[0212] Figure 10 Block diagram 1000 of a device 1005 supporting sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure is shown. The device 1005 may be an example of aspects of the network entity 105 as described herein. The device 1005 may include a receiver 1010, a transmitter 1015, and a communication manager 1020. The device 1005 may also include a processor. Each of these components may communicate with one another (e.g., via one or more buses).

[0213] The receiver 1010 may provide components for obtaining (e.g., receiving, determining, identifying) information associated with various channels (e.g., control channels, data channels, information channels, channels associated with a protocol stack) such as user data, control information, or any combination thereof (e.g., I / Q samples, symbols, packets, protocol data units, service data units). The information may be passed to other components of the device 1005. In some examples, the receiver 1010 may support obtaining information by receiving signals via one or more antennas. Additionally or alternatively, the receiver 1010 may support obtaining information by receiving signals via one or more wired (e.g., electrical, fiber optic) interfaces, wireless interfaces, or any combination thereof.

[0214] The transmitter 1015 may provide a component for outputting (e.g., transmitting, providing, conveying, delivering) information generated by other components of the device 1005. For example, the transmitter 1015 may output information associated with various channels (e.g., control channels, data channels, information channels, channels associated with a protocol stack), such as user data, control information, or any combination thereof (e.g., I / Q samples, symbols, packets, protocol data units, service data units). In some examples, the transmitter 1015 may support outputting information by transmitting signals via one or more antennas. Additionally or alternatively, the transmitter 1015 may support outputting information by transmitting signals via one or more wired (e.g., electrical, optical fiber) interfaces, wireless interfaces, or any combination thereof. In some examples, the transmitter 1015 and the receiver 1010 may be co-located in a transceiver, which may include a modem or be coupled to a modem.

[0215] The communication manager 1020, the receiver 1010, the transmitter 1015, or various combinations or various components thereof may be examples of components for performing various aspects of the sidelink-assisted indication of beam failure as described herein. For example, the communication manager 1020, the receiver 1010, the transmitter 1015, or various combinations or components thereof may support methods for performing one or more of the functions described herein.

[0216] In some examples, the communication manager 1020, the receiver 1010, the transmitter 1015, or various combinations or components thereof may be implemented in hardware (e.g., in a communication management circuit). The hardware may include a processor, a DSP, a CPU, an ASIC, an FPGA, or other programmable logic device, a microcontroller, discrete gate or transistor logic, discrete hardware components, or any combination thereof configured to or otherwise supporting components for performing the functions described in this disclosure. In some examples, a processor and a memory coupled to the processor may be configured to perform one or more of the functions described herein (e.g., by the processor executing instructions stored in the memory).

[0217] Additionally or alternatively, in some examples, the communication manager 1020, the receiver 1010, the transmitter 1015, or various combinations or components thereof may be implemented in code executed by a processor (e.g., implemented as communication management software or firmware). If implemented in code executed by a processor, the functions of the communication manager 1020, the receiver 1010, the transmitter 1015, or various combinations or components thereof may be performed by a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, a microcontroller, or any combination of these or other programmable logic devices configured to or otherwise supporting components for performing the functions described in this disclosure.

[0218] In some examples, the communication manager 1020 may be configured to perform various operations (e.g., receive, obtain, monitor, output, transmit) using or otherwise in cooperation with the receiver 1010, the transmitter 1015, or both. For example, the communication manager 1020 may receive information from the receiver 1010, convey information to the transmitter 1015, or integrate in combination with the receiver 1010, the transmitter 1015, or both to obtain information, output information, or perform various other operations as described herein.

[0219] According to examples disclosed herein, the communication manager 1020 may support wireless communication at a network entity. For example, the communication manager 1020 may be configured to or otherwise support components for the following actions: receive a beam failure recovery request from a first UE, the beam failure recovery request including an indication of whether a beam failure at a second UE is associated with self-interference or cross-link interference. The communication manager 1020 may be configured to or otherwise support components for the following actions: identify one or more beam switching parameters based on the beam failure recovery request, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference. The communication manager 1020 may be configured to or otherwise support components for the following actions: transmit a beam failure recovery response indicating the one or more beam switching parameters.

[0220] By including or configuring a communication manager 1020 according to examples described herein, a device 1005 (e.g., a processor that controls the receiver 1010, the transmitter 1015, the communication manager 1020, or a combination thereof or is otherwise coupled thereto) may support techniques for reducing processing, reducing power consumption, and more efficiently utilizing communication resources.

[0221] Figure 11 Block diagram 1100 illustrates a device 1105 that supports a sidelink assisted indication of a beam failure in accordance with one or more aspects of the present disclosure. The device 1105 may be an example of aspects of the device 1005 or the network entity 105 described herein. The device 1105 may include a receiver 1110, a transmitter 1115, and a communication manager 1120. The device 1105 may also include a processor. Each of these components may communicate with one another (e.g., via one or more buses).

[0222] The receiver 1110 may provide components for obtaining (e.g., receiving, determining, identifying) information associated with various channels (e.g., control channels, data channels, information channels, channels associated with a protocol stack), such as user data, control information, or any combination thereof (e.g., I / Q samples, symbols, packets, protocol data units, service data units). The information may be passed to other components of the device 1105. In some examples, the receiver 1110 may support obtaining information by receiving signals via one or more antennas. Additionally or alternatively, the receiver 1110 may support obtaining information by receiving signals via one or more wired (e.g., electrical, fiber optic) interfaces, wireless interfaces, or any combination thereof.

[0223] The transmitter 1115 may provide components for outputting (e.g., transmitting, providing, conveying, delivering) information generated by other components of the device 1105. For example, the transmitter 1115 may output information associated with various channels (e.g., control channels, data channels, information channels, channels associated with a protocol stack), such as user data, control information, or any combination thereof (e.g., I / Q samples, symbols, packets, protocol data units, service data units). In some examples, the transmitter 1115 may support outputting information by transmitting signals via one or more antennas. Additionally or alternatively, the transmitter 1115 may support outputting information by transmitting signals via one or more wired (e.g., electrical, fiber optic) interfaces, wireless interfaces, or any combination thereof. In some examples, the transmitter 1115 and the receiver 1110 may be co-located in a transceiver that may include a modem or be coupled to a modem.

[0224] The device 1105 or its various components may be examples of components for performing various aspects of the sidelink-assisted indication of beam failure as described herein. For example, the communication manager 1120 may include a BFR request component 1125, a beam switching component 1130, a BFR response component 1135, or any combination thereof. The communication manager 1120 may be an example of aspects of the communication manager 1020 as described herein. In some examples, the communication manager 1120 or its various components may be configured to perform various operations (e.g., receive, obtain, monitor, output, transmit) using or otherwise in cooperation with the receiver 1110, the transmitter 1115, or both. For example, the communication manager 1120 may receive information from the receiver 1110, convey information to the transmitter 1115, or integrate in combination with the receiver 1110, the transmitter 1115, or both to obtain information, output information, or perform various other operations as described herein.

[0225] According to an example as disclosed herein, the communication manager 1120 may support wireless communication at a network entity. The BFR request component 1125 may be configured to or otherwise support components for the following actions: receiving a beam failure recovery request from a first UE, the beam failure recovery request including an indication of whether a beam failure at a second UE is associated with self-interference or cross-link interference. The beam switching component 1130 may be configured to or otherwise support components for the following actions: identifying one or more beam switching parameters based on the beam failure recovery request, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference. The BFR response component 1135 may be configured to or otherwise support components for the following actions: sending a beam failure recovery response indicating the one or more beam switching parameters.

[0226] Figure 12 FIG. 1200 is a block diagram showing a communication manager 1220 that supports sidelink-assisted indication of beam failures, according to one or more aspects of the present disclosure. The communication manager 1220 may be an example of aspects of the communication manager 1020, the communication manager 1120, or both as described herein. The communication manager 1220 or its various components may be examples of components for performing various aspects of the sidelink-assisted indication of beam failures as described herein. For example, the communication manager 1220 may include a BFR request component 1225, a beam switching component 1230, a BFR response component 1235, or any combination thereof. Each of these components may communicate directly or indirectly with each other (e.g., via one or more buses), which communication may include communication within a protocol layer of a protocol stack, communication associated with a logical channel of the protocol stack (e.g., between protocol layers of the protocol stack, within a device, component, or virtualized component associated with the network entity 105, between devices, components, or virtualized components associated with the network entity 105), or any combination thereof.

[0227] According to examples disclosed herein, communication manager 1220 may support wireless communication at a network entity. The BFR request component 1225 may be configured to or otherwise support components for the following actions: receiving a beam failure recovery request from a first UE, the beam failure recovery request including an indication of whether a beam failure at a second UE is associated with self-interference or cross-link interference. The beam switching component 1230 may be configured to or otherwise support components for the following actions: identifying one or more beam switching parameters based on the beam failure recovery request, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference. The BFR response component 1235 may be configured to or otherwise support components for the following actions: sending a beam failure recovery response indicating one or more beam switching parameters.

[0228] In some examples, to support sending the beam failure recovery response, the BFR response component 1235 may be configured to or otherwise support components for the following actions: sending a beam failure recovery response that indicates a change in the uplink beam or downlink beam of the second UE based on whether the beam failure is associated with self-interference or cross-link interference.

[0229] In some examples, to support sending the beam failure recovery response, the BFR response component 1235 may be configured to or otherwise support components for the following actions: sending a beam failure recovery response that includes a request for the second UE to switch from a full-duplex mode to a half-duplex mode.

[0230] In some examples, to support sending the beam failure recovery response, the BFR response component 1235 may be configured to or otherwise support components for the following actions: sending a beam failure recovery response that initiates a beam training process using at least one of a reference signal received power measurement resource, a self-interference measurement resource, and a cross-link interference measurement resource.

[0231] In some examples, to support sending the beam failure recovery response, the BFR response component 1235 may be configured to or otherwise support components for the following actions: sending a beam failure recovery response that includes a command to reduce the power associated with the uplink beam at the second UE, wherein the beam failure recovery response is based on the beam failure being associated with self-interference.

[0232] In some examples, to support sending a beam failure recovery response, the BFR response component 1235 may be configured to or otherwise support components for the following actions: sending a beam failure recovery response that includes a command for a second UE to switch a first uplink beam to a second uplink beam, where the first uplink beam has greater signal interference with a downlink beam than the second uplink beam, and where the beam failure recovery response is based on a beam failure associated with self-interference.

[0233] In some examples, to support sending a beam failure recovery response, the BFR response component 1235 may be configured to or otherwise support components for the following actions: sending a beam failure recovery response that includes a trigger to initiate a process of uplink beam selection with signal interference measurement, where the beam failure recovery response is based on a beam failure associated with cross-link interference.

[0234] Figure 13 A diagram of a system 1300 including a device 1305 that supports sidelink-assisted indication of a beam failure is shown, in accordance with one or more aspects of the present disclosure. The device 1305 may be an example of the device 1005, the device 1105, or the network entity 105 as described herein, or include components thereof. The device 1305 may communicate with one or more network entities 105, one or more UEs 115, or any combination thereof, and the communication may include communication via one or more wired interfaces, via one or more wireless interfaces, or any combination thereof. The device 1305 may include components that support outputting and obtaining communication, such as a communication manager 1320, a transceiver 1310, an antenna 1315, a memory 1325, code 1330, and a processor 1335. These components may be electronically communicated or otherwise (e.g., operatively, communicatively, functionally, electronically, electrically) coupled via one or more buses (e.g., bus 1340).

[0235] The transceiver 1310 may support bidirectional communication via a wired link, a wireless link, or both as described herein. In some examples, the transceiver 1310 may include a wired transceiver and may communicate bidirectionally with another wired transceiver. Additionally or alternatively, in some examples, the transceiver 1310 may include a wireless transceiver and may communicate bidirectionally with another wireless transceiver. In some examples, the device 1305 may include one or more antennas 1315, which may be capable of (e.g., concurrently) sending or receiving wireless transmissions. The transceiver 1310 may also include a modem for: modulating a signal; providing the modulated signal for transmission (e.g., via one or more antennas 1315, via a wired transmitter); receiving the modulated signal (e.g., from one or more antennas 1315, from a wired receiver); and demodulating the signal. In some implementations, the transceiver 1310 may include one or more interfaces, such as one or more interfaces coupled to one or more antennas 1315 configured to support various receiving or obtaining operations, or one or more interfaces coupled to one or more antennas 1315 configured to support various sending or outputting operations, or a combination thereof. In some implementations, the transceiver 1310 may include or be configured to be coupled to one or more processors or memory components, which may be operable to perform or support operations based on received or obtained information or signals, or to generate information or other signals for transmission or other output, or any combination of the above. In some implementations, the transceiver 1310, or the transceiver 1310 and one or more antennas 1315, or the transceiver 1310 and one or more antennas 1315 and one or more processors or memory components (e.g., processor 1335 or memory 1325 or both) may be included in a chip or chip assembly installed in the device 1305. In some examples, the transceiver may be operable to support communications via one or more communication links (eg, communication link 125, backhaul communication link 120, midhaul communication link 162, fronthaul communication link 168).

[0236] The memory 1325 may include RAM and ROM. The memory 1325 may store computer-readable, computer-executable code 1330 including instructions that, when executed by the processor 1335, cause the device 1305 to perform the various functions described herein. The code 1330 may be stored in a non-transitory computer-readable medium (such as system memory or another type of memory). In some cases, the code 1330 may not be directly executable by the processor 1335 but may (e.g., when compiled and executed) cause the computer to perform the functions described herein. In some cases, the memory 1325 may particularly include BIOS, which may control basic hardware or software operations, such as interactions with peripheral components or devices.

[0237] The processor 1335 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, ASICs, CPUs, FPGAs, microcontrollers, programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof). In some cases, the processor 1335 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into the processor 1335. The processor 1335 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1325) to cause the device 1305 to perform various functions (e.g., functions or tasks supporting sidelink-assisted indication of beam failure). For example, the device 1305 or components of the device 1305 may include the processor 1335 and the memory 1325 coupled to the processor 1335, and the processor 1335 and the memory 1325 are configured to perform the various functions described herein. The processor 1335 may be an example of a cloud computing platform (e.g., one or more physical nodes and supporting software such as an operating system, virtual machine, or container instance) that may host functions (e.g., by executing code 1330) to perform the functions of the device 1305. The processor 1335 may be any one or more suitable processors capable of executing scripts or instructions of one or more software programs stored in the device 1305 (such as within the memory 1325). In some specific implementations, the processor 1335 may be a component of a processing system. A processing system generally may refer to a system or series of machines or components that receive inputs and process those inputs to produce a set of outputs (which may be passed to other systems or components of, for example, the device 1305). For example, the processing system of the device 1305 may refer to a system including various other components or sub-components of the device 1305, such as the processor 1335, or the transceiver 1310, or the communication manager 1320, or a combination of other components or components of the device 1305. The processing system of the device 1305 may interface with other components of the device 1305 and may process information (such as inputs or signals) received from other components or output information to other components. For example, a chip or modem of the device 1305 may include a processing system and one or more interfaces for outputting information or for obtaining information or both. One or more interfaces may be implemented as or otherwise include a first interface configured to output information and a second interface configured to obtain information or the same interface configured to output information and obtain information, and other specific implementations. In some specific implementations, one or more interfaces may refer to an interface between the processing system of a chip or modem and a transmitter such that the device 1305 may transmit information output from the chip or modem. Additionally or alternatively, in some specific implementations, one or more interfaces may refer to an interface between the processing system of a chip or modem and a receiver such that the device 1305 may obtain information or signal inputs, and the information may be passed to the processing system.One of ordinary skill in the art will readily recognize that the first interface may also receive information or signal inputs, and the second interface may also output information or signal outputs.

[0238] In some examples, bus 1340 may support communication at the protocol layer (e.g., within the protocol layer) of a protocol stack. In some examples, bus 1340 may support communication associated with a logical channel of a protocol stack (e.g., between protocol layers of the protocol stack), which may include communication performed within components of device 1305, or communication performed between different components of device 1305 that may be co-located or at different locations (e.g., where device 1305 may refer to a system in which one or more of communication manager 1320, transceiver 1310, memory 1325, code 1330, and processor 1335 may be located in one component or divided among different components).

[0239] In some examples, communication manager 1320 may manage (e.g., via one or more wired or wireless backhaul links) aspects of communication with core network 130. For example, communication manager 1320 may manage the delivery of data communication for client devices such as one or more UEs 115. In some examples, communication manager 1320 may manage communication with other network entities 105 and may include a controller or scheduler for coordinating with other network entities 105 to control communication with UEs 115. In some examples, communication manager 1320 may support the X2 interface within LTE / LTE-A wireless communication network technologies to provide communication between network entities 105.

[0240] According to examples disclosed herein, communication manager 1320 may support wireless communication at a network entity. For example, communication manager 1320 may be configured or otherwise support components for the following actions: receiving, from a first UE, a beam failure recovery request that includes an indication of whether a beam failure at a second UE is associated with self-interference or cross-link interference. Communication manager 1320 may be configured or otherwise support components for the following actions: identifying, based on the beam failure recovery request, one or more beam switching parameters, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference. Communication manager 1320 may be configured or otherwise support components for the following actions: transmitting a beam failure recovery response indicating the one or more beam switching parameters.

[0241] By including or configuring a communication manager 1320 according to the examples described herein, device 1305 may support techniques for improving communication reliability, reducing latency, improving the user experience associated with reduced processing, reducing power consumption, more efficiently utilizing communication resources, and improving coordination between devices.

[0242] In some examples, communication manager 1320 may be configured to perform various operations (e.g., receive, obtain, monitor, output, transmit) using or otherwise in conjunction with transceiver 1310, one or more antennas 1315 (e.g., where applicable), or any combination thereof. Although communication manager 1320 is illustrated as a separate component, in some examples, one or more of the functions described with reference to communication manager 1320 may be supported or performed by transceiver 1310, processor 1335, memory 1325, code 1330, or any combination thereof. For example, code 1330 may include instructions executable by processor 1335 to cause device 1305 to perform various aspects of sidelink-assisted indication of beam failure as described herein, or processor 1335 and memory 1325 may otherwise be configured to perform or support such operations.

[0243] Figure 14 A flowchart illustrating a method 1400 for supporting sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure is shown. The operations of method 1400 may be implemented by a UE or its components as described herein. For example, the operations of method 1400 may be performed by a UE 115 as described with reference to Figures 1 to 9 the UE 115 described above. In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functions.

[0244] At 1405, the method may include identifying a beam failure of at least one communication beam at the UE. The operation of 1405 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operation of 1405 may be performed by a beam failure component 825 as described with reference to Figure 8 the beam failure component 825 described above.

[0245] At 1410, the method may include: transmitting, via a sidelink channel, a beam failure recovery request to a network entity that includes an indication of whether the beam failure is associated with self-interference or cross-link interference. The operation of 1410 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operation of 1410 may be performed by a BFR request component 830 as described with reference to Figure 8 the BFR request component 830 described above.

[0246] At 1415, the method may include: receiving a beam failure recovery response indicating one or more beam switching parameters based on a beam failure recovery request, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference. The operations at 1415 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1415 may be performed by a BFR response component 835 as described with reference to Figure 8 described.

[0247] Figure 15 FIG. shows a flow chart of a method 1500 that illustrates support for sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure. The operations of method 1500 may be implemented by a UE or its components as described herein. For example, the operations of method 1500 may be performed by a UE 115 as described with reference to Figures 1 to 9 described. In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functions.

[0248] At 1505, the method may include: receiving an indication of one or more resources associated with a set of multiple beam failure detection reference signals from a network entity. The operations at 1505 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1505 may be performed by a resource indication component 840 as described with reference to Figure 8 described.

[0249] At 1510, the method may include: periodically obtaining at least one of reference signal received power measurements, self-interference measurements, and cross-link interference measurements based on the one or more resources. The operations at 1510 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1510 may be performed by a measurement component 845 as described with reference to Figure 8 described.

[0250] At 1515, the method may include identifying a beam failure of at least one communication beam at the UE. The operations at 1515 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1515 may be performed by a beam failure component 825 as described with reference to Figure 8 described.

[0251] At 1520, the method may include: transmitting, via a sidelink channel, a beam failure recovery request to the network entity that includes an indication of whether the beam failure is associated with self-interference or cross-link interference. The operations at 1520 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1520 may be performed by a component as described with reference to Figure 8performed by the described BFR request component 830.

[0252] At 1525, the method may include: receiving, based on a beam failure recovery request, a beam failure recovery response indicating one or more beam switching parameters, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference. The operation at 1525 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operation at 1525 may be performed by the BFR response component 835 as described with reference to Figure 8 the described BFR response component 835.

[0253] Figure 16 FIG. shows a flowchart of a method 1600 that illustrates support for sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure. The operations of method 1600 may be implemented by a UE or its components as described herein. For example, the operations of method 1600 may be performed by the UE 115 as described with reference to Figures 1 to 9 the described UE 115. In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functions.

[0254] At 1605, the method may include identifying a beam failure of at least one communication beam at the UE. The operation at 1605 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operation at 1605 may be performed by the beam failure component 825 as described with reference to Figure 8 the described beam failure component 825.

[0255] At 1610, the method may include: transmitting, via a sidelink channel, a beam failure recovery request to a network entity that includes an indication of whether the beam failure is associated with self-interference or cross-link interference. The operation at 1610 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operation at 1610 may be performed by the BFR request component 830 as described with reference to Figure 8 the described BFR request component 830.

[0256] At 1615, the method may include transmitting control signaling that includes at least one of the following: an indication of increased self-interference, an indication of increased cross-link interference, an identifier of self-interference that causes a beam failure, an identifier of cross-link interference that causes a beam failure, a cross-link interference beam indication that causes cross-link interference, an uplink beam identifier that causes self-interference, a transmit-receive point identifier associated with a beam failure, a UE identifier, a cell identifier, an indication of a set of preferred beams for downlink or uplink or both, or a combination thereof. The operations at 1615 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1615 may be performed by a BFR request component 830 as described with reference to Figure 8 the BFR request component 830 described in

[0257] At 1620, the method may include: receiving, based on a beam failure recovery request, a beam failure recovery response that indicates one or more beam switching parameters, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference. The operations at 1620 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1620 may be performed by a BFR response component 835 as described with reference to Figure 8 the BFR response component 835 described in

[0258] Figure 17 FIG. shows a flow chart of a method 1700 that illustrates side-link assisted indication of a beam failure in accordance with one or more aspects of the present disclosure. The operations of method 1700 may be implemented by a UE or its components as described herein. For example, the operations of method 1700 may be performed by a UE 115 as described with reference to Figures 1 to 9 the UE 115 described in

[0259] At 1705, the method may include identifying a beam failure of at least one communication beam at the UE. The operations at 1705 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1705 may be performed by a beam failure component 825 as described with reference to Figure 8 the beam failure component 825 described in

[0260] At 1710, the method may include: identifying a set of multiple sidelink relay UEs for transmitting a beam failure recovery request. The operations at 1710 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1710 may be performed by a UE identification component 850 as described with reference to Figure 8 the UE identification component 850 described in

[0261] At 1715, the method may include selecting a sidelink relay UE for sending a beam failure recovery request from a set of multiple sidelink relay UEs based on: determining that the UE is capable of connecting to the sidelink relay UE using a latency value that meets a threshold latency value. The operation at 1715 may be performed according to the examples disclosed herein. In some examples, aspects of the operation at 1715 may be performed by a UE selection component 855 as described with reference to Figure 8 as described.

[0262] At 1720, the method may include: sending, via a sidelink channel, a beam failure recovery request to a network entity, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference. The operation at 1720 may be performed according to the examples disclosed herein. In some examples, aspects of the operation at 1720 may be performed by a BFR request component 830 as described with reference to Figure 8 as described.

[0263] At 1725, the method may include: receiving, based on the beam failure recovery request, a beam failure recovery response indicating one or more beam switching parameters, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference. The operation at 1725 may be performed according to the examples disclosed herein. In some examples, aspects of the operation at 1725 may be performed by a BFR response component 835 as described with reference to Figure 8 as described.

[0264] Figure 18 FIG. shows a flow diagram of a method 1800 for supporting sidelink-assisted indication of beam failure in accordance with one or more aspects of the present disclosure. The operations of method 1800 may be implemented by a network entity or its components as described herein. For example, the operations of method 1800 may be performed by a network entity as described with reference to Figures 1 to 5 and Figures 10 to 13 as described. In some examples, the network entity may execute an instruction set to control functional elements of the network entity to perform the described functions. Additionally or alternatively, the network entity may use dedicated hardware to perform aspects of the described functions.

[0265] At 1805, the method may include: receiving, from a first UE, a beam failure recovery request, the beam failure recovery request including an indication of whether a beam failure at a second UE is associated with self-interference or cross-link interference. The operation at 1805 may be performed according to the examples disclosed herein. In some examples, aspects of the operation at 1805 may be performed by a BFR request component 1225 as described with reference to Figure 12 as described.

[0266] At 1810, the method may include: identifying one or more beam switching parameters based on a beam failure recovery request that includes an indication of whether the beam failure is associated with self-interference or cross-link interference. The operations at 1810 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1810 may be performed by a beam switching component 1230 as described with reference to Figure 12 as described.

[0267] At 1815, the method may include: transmitting a beam failure recovery response indicating one or more beam switching parameters. The operations at 1815 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1815 may be performed by a BFR response component 1235 as described with reference to Figure 12 described.

[0268] Figure 19 FIG. shows a flow diagram of a method 1900 that illustrates support for sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure. The operations of method 1900 may be implemented by a network entity or its components as described herein. For example, the operations of method 1900 may be performed by a network entity as described with reference to Figures 1 to 5 and Figures 10 to 13 described. In some examples, the network entity may execute an instruction set to control functional elements of the network entity to perform the described functions. Additionally or alternatively, the network entity may use dedicated hardware to perform aspects of the described functions.

[0269] At 1905, the method may include: receiving, from a first UE, a beam failure recovery request that includes an indication of whether the beam failure at a second UE is associated with self-interference or cross-link interference. The operations at 1905 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1905 may be performed by a BFR request component 1225 as described with reference to Figure 12 described.

[0270] At 1910, the method may include: identifying one or more beam switching parameters based on a beam failure recovery request that includes an indication of whether the beam failure is associated with self-interference or cross-link interference. The operations at 1910 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1910 may be performed by a beam switching component 1230 as described with reference to Figure 12 described.

[0271] At 1915, the method may include: sending a beam failure recovery response indicating one or more beam switching parameters. The operations at 1915 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1915 may be performed by a BFR response component 1235 as described with reference to Figure 12 described.

[0272] At 1920, the method may include: sending a beam failure recovery response that indicates a change in an uplink beam or a downlink beam of a second UE based on whether the beam failure is associated with self-interference or cross-link interference. The operations at 1920 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 1920 may be performed by a BFR response component 1235 as described with reference to Figure 12 described.

[0273] Figure 20 FIG. shows a flowchart of a method 2000 that illustrates support for sidelink-assisted indication of beam failures in accordance with one or more aspects of the present disclosure. The operations of method 2000 may be implemented by a network entity or its components as described herein. For example, the operations of method 2000 may be performed by a network entity as described with reference to Figures 1 to 5 and Figures 10 to 13 described. In some examples, the network entity may execute an instruction set to control functional elements of the network entity to perform the described functions. Additionally or alternatively, the network entity may use dedicated hardware to perform aspects of the described functions.

[0274] At 2005, the method may include: receiving, from a first UE, a beam failure recovery request that includes an indication of whether a beam failure at a second UE is associated with self-interference or cross-link interference. The operations at 2005 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 2005 may be performed by a BFR request component 1225 as described with reference to Figure 12 described.

[0275] At 2010, the method may include: identifying one or more beam switching parameters based on the beam failure recovery request, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference. The operations at 2010 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 2010 may be performed by a beam switching component 1230 as described with reference to Figure 12 described.

[0276] At 2015, the method may include: sending a beam failure recovery response indicating one or more beam switching parameters. The operations at 2015 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 2015 may be performed by a BFR response component 1235 as described with reference to Figure 12 the BFR response component 1235 described.

[0277] At 2020, the method may include: sending a beam failure recovery response that includes a request for a second UE to switch from a full-duplex mode to a half-duplex mode. The operations at 2020 may be performed in accordance with the examples disclosed herein. In some examples, aspects of the operations at 2020 may be performed by a BFR response component 1235 as described with reference to Figure 12 the BFR response component 1235 described.

[0278] An overview of aspects of the present disclosure is provided below:

[0279] Aspect 1: A method for wireless communication at a UE, the method including: identifying a beam failure of at least one communication beam at the UE; sending, via a sidelink channel, a beam failure recovery request to a network entity that includes an indication of whether the beam failure is associated with self-interference or cross-link interference; and receiving, at least in part based on the beam failure recovery request, a beam failure recovery response indicating one or more beam switching parameters, the beam failure recovery request including the indication of whether the beam failure is associated with the self-interference or the cross-link interference.

[0280] Aspect 2: The method according to aspect 1, the method further including: receiving, from the network entity, an indication of one or more resources associated with a plurality of beam failure detection reference signals; and periodically obtaining at least one of a reference signal received power measurement, a self-interference measurement, and a cross-link interference measurement, at least in part based on the one or more resources.

[0281] Aspect 3: The method according to any one of aspects 1 to 2, wherein sending the beam failure recovery request includes: sending control signaling that includes at least one of the following: an indication of increased self-interference, an indication of increased cross-link interference, an identifier of the self-interference that caused the beam failure, an identifier of the cross-link interference that caused the beam failure, a cross-link interference beam indication that caused cross-link interference, an uplink beam identifier that caused the self-interference, a transmit-receive point identifier associated with the beam failure, a UE identifier, a cell identifier, an indication of a set of preferred beams for downlink or uplink or both, or a combination thereof.

[0282] Aspect 4: The method according to any one of Aspects 1 to 3, the method further comprising: identifying a plurality of sidelink relay UEs for transmitting the beam failure recovery request; and selecting, at least in part based on the following aspects, a sidelink relay UE from the plurality of sidelink relay UEs for transmitting the beam failure recovery request: determining that the UE can connect to the sidelink relay UE using a latency value that meets a threshold latency value.

[0283] Aspect 5: The method according to Aspect 4, the method further comprising: identifying the plurality of sidelink relay UEs for transmitting the beam failure recovery request, at least in part based on each sidelink relay UE in the plurality of sidelink relay UEs being associated with at least one of the following: a threshold sidelink latency, a threshold uplink latency, a threshold sidelink link quality, a threshold uplink link quality, a sidelink relay mode setting parameter, the connectivity between each sidelink relay UE and the network entity, the connectivity between each sidelink relay UE and a second network entity, or a combination thereof.

[0284] Aspect 6: The method according to any one of Aspects 4 to 5, wherein transmitting the beam failure recovery request further comprises: transmitting the beam failure recovery request to the sidelink relay UE in the plurality of sidelink relay UEs, at least in part based on one or more conditions.

[0285] Aspect 7: The method according to any one of Aspects 4 to 6, the method further comprising: receiving an indication of the threshold latency value from the network entity, wherein the threshold latency value is at least in part based on the random access channel configuration periodicity.

[0286] Aspect 8: The method according to any one of Aspects 4 to 7, wherein the UE can connect to the sidelink relay UE using a sidelink grant or sensed sidelink resources.

[0287] Aspect 9: The method according to any one of Aspects 1 to 8, the method further comprising: receiving, from a sidelink relay UE, an indication of at least one of the following: the availability of an uplink grant at the sidelink relay UE, the periodicity associated with the uplink grant, the offset associated with the uplink grant, the delay between two uplink grants, the time and frequency resources per occasion, the physical layer uplink priority, or a combination thereof, wherein the availability of the uplink grant is at least in part based on scheduling request information, configured grant information, dynamic grant information.

[0288] Aspect 10: The method according to any one of Aspects 1 to 9, the method further comprising: receiving, from a sidelink relay UE, signaling indicating the downlink quality or the estimated uplink quality or both of each cell identifier or network entity identifier associated with the sidelink relay UE, wherein the signaling comprises broadcast signaling or unicast signaling.

[0289] Aspect 11: The method according to any one of Aspects 1 to 10, the method further comprising: receiving, from a sidelink relay UE, an indicator indicating the relay capability of the sidelink relay UE, wherein the indicator is received periodically or cyclically.

[0290] Aspect 12: The method according to any one of Aspects 1 to 11, the method further comprising: receiving, from a sidelink relay UE, at least one of a distributed unit identifier, a transmit-receive point identifier, a cell identifier, a network entity identifier, or a combination thereof.

[0291] Aspect 13: The method according to any one of Aspects 1 to 12, wherein receiving the beam failure recovery response comprises: receiving the beam failure recovery response, the beam failure recovery response indicating a change in the uplink beam or downlink beam of the UE at least in part based on whether the beam failure is associated with the self-interference or the cross-link interference.

[0292] Aspect 14: The method according to any one of Aspects 1 to 13, wherein receiving the beam failure recovery response comprises: receiving the beam failure recovery response, the beam failure recovery response comprising a request for the UE to switch from a full-duplex mode to a half-duplex mode.

[0293] Aspect 15: The method according to any one of Aspects 1 to 14, wherein receiving the beam failure recovery response comprises: receiving the beam failure recovery response, the beam failure recovery response initiating a beam training process using at least one of a reference signal received power measurement resource, a self-interference measurement resource, and a cross-link interference measurement resource; and performing the beam training process to establish a second communication beam.

[0294] Aspect 16: The method according to any one of Aspects 1 to 15, wherein receiving the beam failure recovery response comprises: receiving the beam failure recovery response, the beam failure recovery response comprising a command to reduce the power associated with the uplink beam at the UE, wherein the beam failure recovery response is at least in part based on the beam failure being associated with the self-interference.

[0295] Aspect 17: The method according to any one of aspects 1 to 16, wherein receiving the beam failure recovery response includes: receiving the beam failure recovery response, the beam failure recovery response including a command for the UE to switch a first uplink beam to a second uplink beam, wherein the first uplink beam has a greater signal interference with the at least one communication beam than the second uplink beam, and wherein the beam failure recovery response is at least partially based on the beam failure being associated with the self-interference.

[0296] Aspect 18: The method according to aspect 17, the method further comprising: determining that the signal interference between the second uplink beam and the at least one communication beam is greater than a threshold; and switching from a full-duplex mode to a half-duplex mode or canceling uplink transmission at least partially based on the signal interference being greater than the threshold.

[0297] Aspect 19: The method according to any one of aspects 1 to 18, wherein receiving the beam failure recovery response includes: receiving the beam failure recovery response, the beam failure recovery response including a trigger for initiating a process of uplink beam selection with signal interference measurement, wherein the beam failure recovery response is at least partially based on the beam failure being associated with the cross-link interference.

[0298] Aspect 20: The method according to any one of aspects 1 to 19, the method further comprising: sending a set of intermediate cross-link interference reports to a second UE associated with the cross-link interference at least partially based on identifying the beam failure; identifying a set of beams that meet a cross-link interference threshold at least partially based on sending the set of intermediate cross-link interference reports; and sending an indication of the set of beams that meet the cross-link interference threshold.

[0299] Aspect 21: The method according to aspect 20, wherein the indication of the set of beams that meet the cross-link interference threshold is sent from the UE to the network entity or sent to the network entity via the second UE.

[0300] Aspect 22: A method for wireless communication at a network entity, the method comprising: receiving a beam failure recovery request from a first UE, the beam failure recovery request including an indication of whether a beam failure at a second UE is associated with self-interference or cross-link interference; identifying one or more beam switching parameters at least partially based on the beam failure recovery request, the beam failure recovery request including the indication of whether the beam failure is associated with the self-interference or the cross-link interference; and sending a beam failure recovery response indicating the one or more beam switching parameters.

[0301] Aspect 23: The method according to aspect 22, wherein transmitting the beam failure recovery response includes: transmitting the beam failure recovery response, the beam failure recovery response indicating a change in the uplink beam or downlink beam of the second UE at least in part based on whether the beam failure is associated with the self-interference or the cross-link interference.

[0302] Aspect 24: The method according to any one of aspects 22 to 23, wherein transmitting the beam failure recovery response includes: transmitting the beam failure recovery response, the beam failure recovery response including a request for the second UE to switch from the full-duplex mode to the half-duplex mode.

[0303] Aspect 25: The method according to any one of aspects 22 to 24, wherein transmitting the beam failure recovery response includes: transmitting the beam failure recovery response, the beam failure recovery response initiating a beam training process using at least one of a reference signal received power measurement resource, a self-interference measurement resource, and a cross-link interference measurement resource.

[0304] Aspect 26: The method according to any one of aspects 22 to 25, wherein transmitting the beam failure recovery response includes: transmitting the beam failure recovery response, the beam failure recovery response including a command to reduce the power associated with the uplink beam at the second UE, wherein the beam failure recovery response is at least in part based on the beam failure being associated with the self-interference.

[0305] Aspect 27: The method according to any one of aspects 22 to 26, wherein transmitting the beam failure recovery response includes: transmitting the beam failure recovery response, the beam failure recovery response including a command for the second UE to switch a first uplink beam to a second uplink beam, wherein the first uplink beam has a greater signal interference with the downlink beam than the second uplink beam, and wherein the beam failure recovery response is at least in part based on the beam failure being associated with the self-interference.

[0306] Aspect 28: The method according to any one of aspects 22 to 27, wherein transmitting the beam failure recovery response includes: transmitting the beam failure recovery response, the beam failure recovery response including a trigger to initiate a process of uplink beam selection with signal interference measurement, wherein the beam failure recovery response is at least in part based on the beam failure being associated with the cross-link interference.

[0307] Aspect 29: An apparatus for wireless communication at a UE, the apparatus 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 according to any one of Aspects 1 to 21.

[0308] Aspect 30: An apparatus for wireless communication at a UE, the apparatus comprising: at least one component for performing the method according to any one of Aspects 1 to 21.

[0309] Aspect 31: A non-transitory computer-readable medium storing code for wireless communication at a UE, the code comprising instructions executable by a processor to perform the method according to any one of Aspects 1 to 21.

[0310] Aspect 32: An apparatus for wireless communication at a network entity, the apparatus 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 according to any one of Aspects 22 to 28.

[0311] Aspect 33: An apparatus for wireless communication at a network entity, the apparatus comprising: at least one component for performing the method according to any one of Aspects 22 to 28.

[0312] Aspect 34: A non-transitory computer-readable medium storing code for wireless communication at a network entity, the code comprising instructions executable by a processor to perform the method according to any one of Aspects 22 to 28.

[0313] It should be noted that the methods described herein describe possible specific implementations, and the operations and steps can be rearranged or otherwise modified and other specific implementations are also possible. In addition, aspects from two or more methods can be combined.

[0314] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for example purposes and the terms LTE, LTE-A, LTE-A Pro, or NR may be used in much of the description, the techniques described herein may also apply to networks other than LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may apply to various other wireless communication systems such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0315] The information and signals described herein may be represented using any of a variety of different technologies and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips referred to throughout the specification may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0316] The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed using a general purpose processor, DSP, ASIC, CPU, FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0317] The functions described herein may be implemented using hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions may be stored as one or more instructions or code on a computer-readable medium or transmitted using one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination of these items. The features implementing the functions may also be physically located at different positions, including being distributed such that portions of the functions are implemented at different physical locations.

[0318] A computer-readable medium includes both a non-transitory computer storage medium and a communication medium including any medium that facilitates transfer of a computer program from one location to another. A non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media can include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disc read only memory (CD-ROM) or other optical disc storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code components in the form of instructions or data structures and that can be accessed by a general purpose or special purpose computer or a general purpose or special purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. As used herein, disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc. Disk may reproduce data magnetically, while disc may reproduce data optically using lasers. Combinations of the above are also included within the scope of computer-readable medium.

[0319] As used herein, including in the claims, the "or" used in a list of items (e.g., a list of items accompanied by a phrase such as "at least one of" or "one or more of") indicates an inclusive listing such that, for example, the listing of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Additionally, as used herein, the phrase "based on" should not be construed as a reference to a closed set of conditions. For example, an example step described as "based on condition A" may be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "at least partially based on".

[0320] The term "determine" encompasses a variety of actions, and thus, "determine" can include operations, calculations, processing, derivations, inquiries, lookups (such as looking up in a table, database, or other data structure), ascertaining, and the like. Additionally, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data stored in a memory), etc. Further, "determine" can include parsing, obtaining, selecting, choosing, establishing, and other such similar actions.

[0321] In the accompanying drawings, like components or features may have the same reference numerals. Additionally, various components of the same type can be distinguished by adding a dash and a second numeral used to differentiate between like components after the reference numeral. If only the first reference numeral is used in the specification, the description can apply to any one of the like components having the same first reference numeral, regardless of the second reference numeral or any other subsequent reference numerals.

[0322] The description set forth herein in conjunction with the accompanying drawings describes example configurations and does not represent all examples that may be implemented or that are within the scope of the claims. The term "example" as used herein means "serving as an example, instance, or illustration" and not "preferred" or "advantageous over other examples". The detailed description includes specific details for providing an understanding of the described techniques. However, the techniques may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0323] The present description is provided to enable a person of ordinary skill in the art to make or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein and is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: Processor; Memory coupled to the processor; And Instructions stored in the memory and executable by the processor to cause the device to: Identify a beam failure of at least one communication beam at the UE; Send, via a sidelink channel, a beam failure recovery request to a network entity, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference; And Receive, at least in part based on the beam failure recovery request, a beam failure recovery response indicating one or more beam switching parameters, the beam failure recovery request including the indication of whether the beam failure is associated with the self-interference or the cross-link interference.

2. The apparatus according to claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: Receive an indication of one or more resources associated with a plurality of beam failure detection reference signals from the network entity; and Periodically obtain at least one of a reference signal received power measurement, a self-interference measurement, and a cross-link interference measurement at least partially based on the one or more resources.

3. The apparatus according to claim 1, wherein the instructions for sending the beam failure recovery request are executable by the processor to cause the apparatus to: Send control signaling comprising at least one of: an indication of increased self-interference, an indication of increased cross-link interference, an identifier of the self-interference that caused the beam failure, an identifier of the cross-link interference that caused the beam failure, a cross-link interference beam indication that caused cross-link interference, an uplink beam identifier that caused the self-interference, a transmit-receive point identifier associated with the beam failure, a UE identifier, a cell identifier, an indication of a set of preferred beams for downlink or uplink or both, or a combination thereof.

4. The apparatus according to claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: Identify a plurality of sidelink relay UEs for sending the beam failure recovery request; and Select a sidelink relay UE from the plurality of sidelink relay UEs for sending the beam failure recovery request at least partially based on: determining that the UE can connect to the sidelink relay UE using a delay value that meets a threshold delay value.

5. The apparatus according to claim 4, wherein the instructions are further executable by the processor to cause the apparatus to: Identify the plurality of sidelink relay UEs for transmitting the beam failure recovery request at least in part based on each sidelink relay UE among the plurality of sidelink relay UEs being associated with at least one of: a threshold sidelink delay, a threshold uplink delay, a threshold sidelink link quality, a threshold uplink link quality, a sidelink relay mode setting parameter, the connectivity between each sidelink relay UE and the network entity, the connectivity between each sidelink relay UE and a second network entity, or a combination thereof.

6. The apparatus according to claim 4, wherein the instructions for transmitting the beam failure recovery request can be further executed by the processor to cause the apparatus to: Transmit the beam failure recovery request to the sidelink relay UE among the plurality of sidelink relay UEs at least in part based on one or more conditions.

7. The apparatus according to claim 4, wherein the instructions can be further executed by the processor to cause the apparatus to: Receive an indication of the threshold delay value from the network entity, wherein the threshold delay value is at least in part based on the random access channel configuration periodicity.

8. The apparatus according to claim 4, wherein the UE can connect to the sidelink relay UE using a sidelink grant or sensed sidelink resources.

9. The apparatus according to claim 1, wherein the instructions can be further executed by the processor to cause the apparatus to: Receive an indication from a sidelink relay UE of at least one of: the availability of an uplink grant at the sidelink relay UE, the periodicity associated with the uplink grant, the offset associated with the uplink grant, the delay between two uplink grants, the time and frequency resources per occasion, the physical layer uplink priority, or a combination thereof, wherein the uplink grant availability is at least in part based on scheduling request information, configured grant information, dynamic grant information.

10. The apparatus according to claim 1, wherein the instructions can be further executed by the processor to cause the apparatus to: Receive signaling from a sidelink relay UE indicating the downlink quality or the estimated uplink quality or both of each cell identifier or network entity identifier associated with the sidelink relay UE, wherein the signaling includes broadcast signaling or unicast signaling.

11. The apparatus according to claim 1, wherein the instructions can be further executed by the processor to cause the apparatus to: Receive an indicator from a sidelink relay UE indicating the relay capability of the sidelink relay UE, wherein the indicator is received periodically or at regular intervals.

12. The apparatus according to claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: Receive at least one of a distributed unit identifier, a transmit - receive point identifier, a cell identifier, a network entity identifier, or a combination thereof from a side - link relay UE.

13. The apparatus according to claim 1, wherein the instructions for receiving the beam failure recovery response are executable by the processor to cause the apparatus to: Receive the beam failure recovery response, the beam failure recovery response indicating a change in an uplink beam or a downlink beam of the UE at least partially based on whether the beam failure is associated with the self - interference or the cross - link interference.

14. The apparatus according to claim 1, wherein the instructions for receiving the beam failure recovery response are executable by the processor to cause the apparatus to: Receive the beam failure recovery response, the beam failure recovery response including a request for the UE to switch from a full - duplex mode to a half - duplex mode.

15. The apparatus according to claim 1, wherein the instructions for receiving the beam failure recovery response are executable by the processor to cause the apparatus to: Receive the beam failure recovery response, the beam failure recovery response initiating a beam training process using at least one of a reference signal received power measurement resource, a self - interference measurement resource, and a cross - link interference measurement resource; and Execute the beam training process to establish a second communication beam.

16. The apparatus according to claim 1, wherein the instructions for receiving the beam failure recovery response are executable by the processor to cause the apparatus to: Receive the beam failure recovery response, the beam failure recovery response including a command to reduce the power associated with an uplink beam at the UE, wherein the beam failure recovery response is at least partially based on the beam failure being associated with the self - interference.

17. The apparatus according to claim 1, wherein the instructions for receiving the beam failure recovery response are executable by the processor to cause the apparatus to: Receive the beam failure recovery response, the beam failure recovery response including a command for the UE to switch a first uplink beam to a second uplink beam, wherein the first uplink beam has a greater signal interference with the at least one communication beam than the second uplink beam, and wherein the beam failure recovery response is at least partially based on the beam failure being associated with the self - interference.

18. The apparatus according to claim 17, wherein the instructions are further executable by the processor to cause the apparatus to: determine that the signal interference between the second uplink beam and the at least one communication beam is greater than a threshold; and switch from a full-duplex mode to a half-duplex mode or cancel an uplink transmission at least partially based on the signal interference being greater than the threshold.

19. The apparatus according to claim 1, wherein the instructions for receiving the beam failure recovery response are executable by the processor to cause the apparatus to: receive the beam failure recovery response, the beam failure recovery response including a trigger to initiate a process of uplink beam selection with signal interference measurement, wherein the beam failure recovery response is at least partially based on the beam failure being associated with the cross-link interference.

20. The apparatus according to claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: send a set of intermediate cross-link interference reports to a second UE associated with the cross-link interference at least partially based on identifying the beam failure; identify a set of beams that meet a cross-link interference threshold at least partially based on sending the set of intermediate cross-link interference reports; and send an indication of the set of beams that meet the cross-link interference threshold.

21. The apparatus according to claim 20, wherein the indication of the set of beams that meet the cross-link interference threshold is sent from the UE to the network entity or sent to the network entity via the second UE.

22. An apparatus for wireless communication at a network entity, the apparatus comprising: Processor; Memory coupled to the processor; And Instructions stored in the memory and executable by the processor to cause the device to: Receive a beam failure recovery request from a first user equipment (UE), the beam failure recovery request including an indication of whether a beam failure at a second UE is associated with self-interference or cross-link interference; Identify, at least in part based on the beam failure recovery request, one or more beam switching parameters, the beam failure recovery request including the indication of whether the beam failure is associated with the self-interference or the cross-link interference; and Send a beam failure recovery response indicating the one or more beam switching parameters.

23. The apparatus according to claim 22, wherein the instructions for sending the beam failure recovery response are executable by the processor to cause the apparatus to: Transmit the beam failure recovery response, the beam failure recovery response indicating a change in the uplink beam or downlink beam of the second UE based at least in part on whether the beam failure is associated with the self-interference or the cross-link interference.

24. The apparatus according to claim 22, wherein the instructions for transmitting the beam failure recovery response are executable by the processor to cause the apparatus to: Transmit the beam failure recovery response, the beam failure recovery response including a request for the second UE to switch from the full-duplex mode to the half-duplex mode.

25. The apparatus according to claim 22, wherein the instructions for transmitting the beam failure recovery response are executable by the processor to cause the apparatus to: Transmit the beam failure recovery response, the beam failure recovery response initiating a beam training process using at least one of a reference signal received power measurement resource, a self-interference measurement resource, and a cross-link interference measurement resource.

26. The apparatus according to claim 22, wherein the instructions for transmitting the beam failure recovery response are executable by the processor to cause the apparatus to: Transmit the beam failure recovery response, the beam failure recovery response including a command to reduce the power associated with the uplink beam at the second UE, wherein the beam failure recovery response is based at least in part on the beam failure being associated with the self-interference.

27. The apparatus according to claim 22, wherein the instructions for transmitting the beam failure recovery response are executable by the processor to cause the apparatus to: Transmit the beam failure recovery response, the beam failure recovery response including a command for the second UE to switch a first uplink beam to a second uplink beam, wherein the first uplink beam has a greater signal interference with the downlink beam than the second uplink beam, and wherein the beam failure recovery response is based at least in part on the beam failure being associated with the self-interference.

28. The apparatus according to claim 22, wherein the instructions for transmitting the beam failure recovery response are executable by the processor to cause the apparatus to: Transmit the beam failure recovery response, the beam failure recovery response including a trigger for initiating a process of uplink beam selection with signal interference measurement, wherein the beam failure recovery response is based at least in part on the beam failure being associated with the cross-link interference.

29. A method for wireless communication at a user equipment (UE), the method comprising: Identify a beam failure of at least one communication beam at the UE; Send, via a sidelink channel, a beam failure recovery request to a network entity, the beam failure recovery request including an indication of whether the beam failure is associated with self-interference or cross-link interference; And Receive, at least in part based on the beam failure recovery request, a beam failure recovery response indicating one or more beam switching parameters, the beam failure recovery request including the indication of whether the beam failure is associated with the self-interference or the cross-link interference.

30. A method for wireless communication at a network entity, the method comprising: Receive a beam failure recovery request from a first user equipment (UE), the beam failure recovery request including an indication of whether a beam failure at a second UE is associated with self-interference or cross-link interference; Identify, at least in part based on the beam failure recovery request, one or more beam switching parameters, the beam failure recovery request including the indication of whether the beam failure is associated with the self-interference or the cross-link interference; and Send a beam failure recovery response indicating the one or more beam switching parameters.

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