Applying a timing advance command of an access channel message to a timing advance group of a plurality of timing advance groups

Abstract

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a UE can receive an indication of a first TAG associated with a first wireless link of a serving cell and a second TAG associated with a second wireless link of the serving cell. The UE can transmit a first RACH message based at least in part on a failure of a BFR procedure associated with at least one of a first set of BFD-RSs associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link. The UE can receive a second RACH message indicating a TAC for the serving cell based at least in part on transmitting the first RACH message. The UE can communicate with the serving cell based at least in part on an application of the TAC to the first TAG or the second TAG.

Description

TECHNICAL FIELD

[0001] Aspects of the present disclosure generally relate to wireless communication, and more particularly to techniques and apparatuses for applying a timing advance command of an access channel message to a timing advance group (TAG) of a plurality of TAGs. BACKGROUND

[0002] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems can employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and long term evolution (LTE). LTE / LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3 GPP).

[0003] The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless communication devices to communicate on a municipal, national, regional, and even global level. New Radio (NR), which can be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP). NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) (CP-OFDM) on the downlink, support for

[0004] In some networks, a UE can communicate with a network node via multiple transmission reception points (TRPs). For example, the UE can communicate with the network node via a first wireless link with a first TRP and a second wireless link with a second TRP. The first TRP can be associated with a first timing advance group (TAG) and the second TRP can be associated with a second TAG (e.g., based at least in part on the first TRP and the first TAG being associated with a first control resource set (CORESET) pool index and the second TRP and the second TAG being associated with a second CORESET pool index). A timing advance (TA) of a TAG can be a candidate to select for use in communications between the UE and the network node. For example, a TA of the first TAG can indicate an amount of time to change (e.g., change earlier) uplink communications relative to a timing event associated with downlink communications. In the case of selecting a TA, the UE can use the TA to transmit uplink communications. In this way, the UE can change the timing of communications to account for a propagation delay of signals traveling between the UE and the network node.

[0005] The UE can identify a beam failure of one or more of the first wireless link or the second wireless link (e.g., based on identifying a beam failure detection (BFD) event). Based at least in part on the beam failure, the UE can trigger a per-TRP beam failure recovery (BFR) procedure to reestablish the first wireless link or the second wireless link. If the BFR procedure fails, the UE can initiate a random access procedure.

[0006] In examples employing a per-TRP BFR procedure, a respective set of BFD reference signals (RSs), a respective set of new beam identification RSs (NBI-RSs), and a respective BFD count and a respective timer are associated with a respective one of the first TRP and the second TRP. In examples in which a serving cell (e.g., a special cell (SpCell)) is configured with two sets of BFD-RSs and in the case that all sets of BFD-RSs fail in the serving cell, the UE can trigger a contention-based random access (CBRA) procedure. Additionally, in the case that at least one of the sets of BFD-RSs fails, a physical uplink control channel (PUCCH) scheduling request (SR) is not configured, and no uplink grant is available, the UE can trigger a CBRA. During a random access procedure associated with the CBRA, the network node can transmit an indication of a timing advance command (TAC) to indicate a TA to use during or after the random access procedure. SUMMARY

[0007] Some aspects described herein relate to a method of wireless communication performed by a user equipment (UE). The method can include receiving an indication of a first timing advance group (TAG) associated with a first wireless link of a serving cell and a second TAG associated with a second wireless link of the serving cell. The method can include transmitting a first random access channel (RACH) message on the serving cell based at least in part on a failure of a beam failure recovery (BFR) procedure associated with at least one of a first set of beam failure detection (BFD) reference signals (RSs) associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link. The method can include receiving a second RACH message indicating a timing advance command (TAC) for the serving cell based at least in part on transmitting the first RACH message. The method can include communicating with the serving cell based at least in part on an application of the TAC to the first TAG or the second TAG based at least in part on one or more of: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to the transmission of the first RACH message; a set of BFD-RSs of the first set of BFD-RSs or the second set of BFD-RSs that is not the at least one set of BFD-RSs for which a BFR procedure was not triggered; or a synchronization signal block (SSB) associated with the first RACH message.

[0008] Some aspects described herein relate to a UE for wireless communication. The user equipment can include at least one processor and at least one memory storing processor-readable code, the at least one memory communicatively coupled with the at least one processor. The processor-readable code, when executed by the at least one processor, can be configured to cause the user equipment to receive an indication of a first TAG associated with a first wireless link of a serving cell and a second TAG associated with a second wireless link of the serving cell. The processor-readable code, when executed by the at least one processor, can be configured to cause the user equipment to transmit a first RACH message on the serving cell based at least in part on a failure of a BFR procedure associated with at least one of a first set of BFD-RSs associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link. The processor-readable code, when executed by the at least one processor, can be configured to cause the user equipment to receive a second RACH message indicating a TAC for the serving cell based at least in part on transmitting the first RACH message. The processor-readable code, when executed by the at least one processor, can be configured to cause the user equipment to communicate with the serving cell based at least in part on an application of the TAC to the first TAG or the second TAG based at least in part on one or more of: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to transmission of the first RACH message; a set of BFD-RSs of the first set of BFD-RSs or the second set of BFD-RSs that is not the at least one set of BFD-RSs for which a BFR procedure was not triggered; or a SSB associated with the first RACH message.

[0009] Some aspects described herein relate to a non-transitory computer-readable medium storing a set of instructions for wireless communication by a UE. The set of instructions, when executed by one or more processors of the UE, can cause the UE to receive an indication of a first TAG associated with a first wireless link of a serving cell and a second TAG associated with a second wireless link of the serving cell. The set of instructions, when executed by the one or more processors of the UE, can cause the UE to transmit a first RACH message on the serving cell based at least in part on a failure of a BFR procedure associated with at least one of a first set of BFD-RSs associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link. The set of instructions, when executed by the one or more processors of the UE, can cause the UE to receive a second RACH message indicating a TAC for the serving cell based at least in part on transmitting the first RACH message. The set of instructions, when executed by the one or more processors of the UE, can cause the UE to communicate with the serving cell based at least in part on an application of the TAC to the first TAG or the second TAG based at least in part on one or more of: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to transmission of the first RACH message; a set of BFD-RSs of the first set of BFD-RSs or the second set of BFD-RSs that is not the at least one set of BFD-RSs for which a BFR procedure was not triggered; or an SSB associated with the first RACH message.

[0010] Some aspects described herein relate to an apparatus for wireless communication. The apparatus can include means for receiving an indication of a first TAG associated with a first wireless link of a serving cell and a second TAG associated with a second wireless link of the serving cell. The apparatus can include means for transmitting a first RACH message on the serving cell based at least in part on a failure of a BFR procedure associated with at least one of a first set of BFD-RSs associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link. The apparatus can include means for receiving a second RACH message indicating a TAC for the serving cell based at least in part on transmitting the first RACH message. The apparatus can include means for communicating with the serving cell based at least in part on an application of the TAC to the first TAG or the second TAG based at least in part on one or more of: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to transmission of the first RACH message; a set of BFD-RSs of the first set of BFD-RSs or the second set of BFD-RSs other than the at least one set of BFD-RSs for which a BFR procedure was not triggered; or an SSB associated with the first RACH message.

[0011] Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, network node, network entity, wireless communication device, or processing system as substantially described with reference to and as illustrated by the drawings and specification.

[0012] The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows can be better understood. Additional features and advantages will be described hereinafter which form the subject of the claims of the disclosure. The disclosed conception and specific examples can be readily utilized as bases upon which the other BRIEF DESCRIPTION OF DRAWINGS

[0013] So that the above-recited features and advantages of the present disclosure can be understood in detail, a more particular description, briefly summarized above, can be had by reference to various aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description can admit to other equally effective aspects. Like reference numerals in the various drawings can designate the same or similar elements.

[0014] Figure 1 is a diagram illustrating an example of a wireless network, in accordance with the present disclosure.

[0015] Figure 2 is a diagram illustrating an example network node in communication with a user equipment (UE) in a wireless network, in accordance with the present disclosure.

[0016] Figure 3 is a diagram illustrating an example disaggregated base station architecture, in accordance with the present disclosure.

[0017] Figure 4 is a diagram illustrating an example of a beam failure recovery procedure, in accordance with the present disclosure.

[0018] Figure 5 is a diagram illustrating an example of a four-step random access procedure, in accordance with the present disclosure.

[0019] Figure 6 is a diagram associated with an example of applying a timing advance command (TAC) for an access channel message to a timing advance group (TAG) of multiple TAGs, in accordance with the present disclosure.

[0020] Figure 7 is a diagram illustrating an example of a four-step random access procedure, in accordance with the present disclosure.

[0021] Figure 8 is a diagram illustrating an example of a four-step random access procedure, in accordance with the present disclosure.

[0022] Figure 9 is a diagram illustrating an example of a four-step random access procedure, in accordance with the present disclosure.

[0023] Figure 10 is a diagram illustrating an example of a four-step random access procedure, in accordance with the present disclosure.

[0024] Figure 11 is a diagram illustrating an example of a four-step random access procedure, in accordance with the present disclosure.

[0025] Figure 12 is a flow diagram illustrating an example procedure performed, for example, by a UE supporting selection of a TAG in a multi-TAG communication scheme, applying a TAC received during a random access procedure to the TAG, in accordance with the present disclosure.

[0026] Figure 13 is a diagram of an example apparatus for wireless communication, in accordance with the present disclosure. DETAILED DESCRIPTION

[0027] Various aspects of the present disclosure are more fully described below with reference to the figures. The present disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. One skilled in the art can appreciate that the scope of the present disclosure is intended to cover any aspect of the present disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the present disclosure. For example, an apparatus can be implemented or a method can be practiced using any quantity of the aspects described herein. In addition, the scope of the present disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the present disclosure set forth herein. Any aspect of the present disclosure disclosed herein can be embodied by one or more elements of a claim.

[0028] Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, or algorithms, collectively referred to as "elements". These elements can be implemented using hardware, software, or combinations thereof. Whether such elements are implemented as hardware or software depends on the particular application and design constraints imposed on the overall system.

[0029] Various aspects generally relate to applying a timing advance command (TAC) indicated during a random access procedure to a first timing advance group (TAG) or a second TAG. Some aspects more specifically relate to communicating based at least in part on application of the TAC to the first TAG or the second TAG in a multi-transmit receive point (TRP) scenario. In some aspects, a user equipment (UE) can initiate a random access procedure after a beam failure recovery (BFR) procedure fails.

[0030] In some examples, the UE can apply the TAC to the first TAG based at least in part on failing to identify any new candidate beams for any new beam identification (NBI) reference signal (RS) set when transmitting the first random access message. For example, the UE can apply the TAC to the first TAG based at least in part on the first TAG being associated with a first TAG that is associated with a first TAG index, a lowest TAG identity relative to a second TAG identity associated with a second TAG, or being associated with a default control resource set (CORESET) pool index, among other examples.

[0031] In some other examples, the UE can apply the TAC to the first TAG based at least in part on identifying a new candidate beam in the set of NBI-RS when transmitting the first random access message. For example, the UE can apply the TAC to the first TAG based at least in part on the first TAG being associated with the set of NBI-RS in which the UE identified the new candidate beam.

[0032] In some other examples, the UE can apply the TAC to the first TAG based at least in part on the UE selecting a synchronization signal block (SSB) from the set of NBI-RS associated with the first TAG.

[0033] In some aspects, the UE can identify a first new candidate beam in a first set of NBI-RS associated with a first TAG and a second new candidate beam in a second set of NBI-RS associated with a second TAG when transmitting the first random access message. For example, the UE can apply the TAC to the first TAG based at least in part on the first TAG being associated with the set of NBI-RS to which the selected SSB belongs. The SSB can belong to the set of NBI-RS based at least in part on being received on a beam within the set of NBI-RS.

[0034] In some other examples, the UE can apply the TAC to the first TAG based at least in part on not triggering a BFR procedure for a set of BFD-RS associated with the first TAG. For example, the UE can apply the TAC to the first TAG based at least in part on triggering a BFR procedure for a set of BFD-RS associated with the second TAG.

[0035] In some other examples, the UE can apply the TAC to the first TAG based at least in part on a same CORESET pool index being associated with the first TAG and a SSB associated with the first random access message or the first TAG being associated with a SSB associated with the first random access message.

[0036] Particular aspects of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. In some examples, the described techniques can be used to synchronize application of a TAC to one of multiple TAGs between a UE and a network node, where the TAGs are associated with different TRPs or wireless links of a serving cell. In this way, the UE can apply the TAC to an intended TAG (e.g., intended by the network node) for configuring timing of communications using the intended TAG and associated communication link or beam. Based at least in part on applying the TAC to the intended TAG, the UE and the network node can have improved timing synchronization, reduced error rates, and improved spectral efficiency. In this way, the UE and the network node can conserve power, computational, network, and communication resources that would otherwise be used to detect and correct errors associated with applying the TAC to a non-intended TAG.

[0037] Figure 1 is a diagram illustrating an example of a wireless network in accordance with the present disclosure. The wireless network 100 can be or include elements of a 5G (e.g., NR) network or a 4G (e.g., Long Term Evolution (LTE)) network or a future generation network, among other examples. The wireless network 100 can include one or more network nodes 110 (shown as network node (NN) 110a, network node 110b, network node 110c, and network node 110d), one UE 120, or multiple UEs 120 (shown as UE 120a, UE 120b, UE 120c, UE 120d, and UE 120e), and / or other network entities. A network node 110 is an entity that communicates with UEs 120. As illustrated, the network node 110 can include one or more network nodes. For example, the network node 110 can be an aggregated network node, meaning that the aggregated network node is configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node (e.g., within a single device or unit). As another example, the network node 110 can be a disaggregated network node (sometimes referred to as a disaggregated base station), meaning that the network node 110 is configured to utilize a protocol stack that is physically or logically distributed among two or more nodes, such as one or more central units (CUs), one or more distributed units (DUs), or one or more radio units (RUs).

[0038] In some examples, the network nodes 110 are or include network nodes that communicate with UEs 120 via radio access links, such as RUs. In some examples, the network nodes 110 are or include network nodes that communicate with other network nodes 110 via a front-haul link or a mid-haul link, such as DUs. In some examples, the network nodes 110 are or include network nodes that communicate with other network nodes 110 via a mid-haul link or with a core network via a backhaul link, such as CUs. In some examples, a network node 110 (such as an aggregated network node 110 or a disaggregated network node 110) can include multiple network nodes, such as one or more RUs, one or more CUs, or one or more DUs. The network nodes 110 can include, for example, NR network nodes, LTE network nodes, Node Bs, eNBs (e.g., in 4G), gNBs (e.g., in 5G), access points, transmission reception points (TRPs), DUs, RUs, CUs, mobility elements of a network, core network nodes, network elements, network equipment, or RAN nodes. In some examples, the network nodes 110 can interconnect with one another or to one or more other network nodes 110 in the wireless network 100 using any suitable transport network, through various types of front-haul interfaces, mid-haul interfaces, or backhaul interfaces, such as direct physical connections, over-the-air connections, or virtual networks.

[0039] Each network node 110 can provide communication coverage for a particular geographic area. In Third Generation Partnership Project (3GPP) terminology, the term "cell" can refer to a coverage area of a network node 110 or a subsystem of a network node 110 serving the coverage area, depending on the context in which the term is used.

[0040] The network nodes 110 can provide communication coverage for a macro cell, a pico cell, a femto cell, or another type of cell. A macro cell can cover a relatively large geographic area (e.g., several kilometers in radius) and can allow unrestricted access by UEs 120 with service subscriptions. A pico cell can cover a relatively small geographic area and can allow unrestricted access by UEs 120 with service subscriptions. A femto cell can cover a relatively small geographic area (e.g., a home) and can allow restricted access by UEs 120 with

[0041] Wireless network 100 can be a heterogeneous network that includes network nodes 110 of different types, such as macro network nodes, pico network nodes, femto network nodes, or relay network nodes. These different types of network nodes 110 can have different transmit power levels, different coverage areas, or different impacts on interference in wireless network 100. For example, macro network nodes can have a high transmit power level (e.g., 5 to 40 watts) whereas pico network nodes, femto network nodes, and relay network nodes can have a lower transmit power level (e.g., 0.1 to 2 watts). In Figure 1 In the example shown in FIG. 1, network node 110a can be a macro network node for a macro cell 102a, network node 110b can be a pico network node for a pico cell 102b, and network node 110c can be a femto network node for a femto cell 102c. A network node can support one or more (e.g., three) cells. In some examples, cells can not necessarily be stationary, and the geographic area of a cell can move according to the location of a mobile network node 110 (e.g., a mobile network node).

[0042] In some aspects, the term “base station” or “network node” can refer to a disaggregated base station, an integrated access and backhaul (IAB) node, a relay node, or one or more components thereof. For example, in some aspects, a “base station” or “network node” can refer to a CU, a DU, a RU, a near real-time (near-RT) RAN intelligent controller (RIC), or a non-RT RIC. In some aspects, the term “base station” or “network node” can refer to one device configured to perform one or more functions, such as those described herein in connection with network node 110. In some aspects, the term “base station” or “network node” can refer to multiple devices configured to perform one or more functions. For example, in some distributed systems, each of a number of different devices (which can be located at the same geographic location or at different geographic locations) can be configured to perform at least a portion of a function, or repeat performance of at least a portion of the function, and the term “base station” or “network node” can refer to any one or more of these different devices. In some aspects, the term “base station” or “network node” can refer to one or more virtual base stations or one or more virtual base station functions. For example, in some aspects, two or more base station functions can be instantiated on a single device. In some aspects, the term “base station” or “network node” can refer to one base station function as opposed to another base station function. In this way, a single device can include more than one base station.

[0043] A network controller 130 can couple to a set of network nodes 110 and can provide coordination and control for the network nodes 110. The network controller 130 can communicate with the network nodes 110 via a backhaul communication link. The network nodes 110 can also communicate with one another directly, via wireless backhaul communication links, or via wired backhaul communication links. In some aspects, the network controller 130 can be a CU or a core network device, or the network controller 130 can include a CU or a core network device.

[0044] In some examples, a cell can not necessarily be stationary, and the geographic area of the cell can move according to the location of a mobile network node 110 (e.g., a mobile network node). In some examples, network nodes 110 can be interconnected to one another or to one or more other network nodes (not shown) in wireless network 100 through various types of backhaul interfaces, such as a direct physical connection or a virtual network, using any suitable transport network.

[0045] Wireless network 100 can include one or more relay stations. A relay station is an entity that can receive a transmission of data from an upstream station (e.g., a network node 110 or a UE 120) and send a transmission of the data to a downstream station (e.g., a UE 120 or a network node 110). A relay station can be a UE 120 that can relay transmissions for other UEs 120. In Figure 1 In the example shown in FIG. 1, network node 110d (e.g., a relay network node) can communicate with network node 110a (e.g., a macro network node) and UE 120d in order to facilitate communication between network node 110a and UE 120d. A network node 110 that relays

[0046] UEs 120 can be dispersed throughout wireless network 100, and each UE 120 can be stationary or mobile. A UE 120 can include, for example, an access terminal, a terminal, a mobile station or a subscriber unit. A UE 120 can be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device, a biometric device, a wearable device (e.g., a smart watch, smart clothing, smart glasses, a smart wristband, smart jewelry (e.g., a smart ring or a smart bracelet)), an entertainment device (e.g., a music device, a video device, or a satellite radio), a vehicle component or sensor, a smart meter / sensor, industrial manufacturing equipment, a global positioning system device, a UE function of a network node, or any other suitable device that is configured to communicate via a wireless medium.

[0047] Some UEs 120 can be considered machine-type communication (MTC) or evolved or enhanced machine-type communication (eMTC) UEs. MTC or eMTC UEs can include, for example, robots, drones, remote devices, sensors, meters, monitors, or location tags, that can communicate with a network node, another device (e.g., remote device), or some other entity. A some UEs 120 can be considered Intemet-of-Things (IoT) devices, or can be implemented as NB-IoT (narrowband IoT) devices. Some UEs 120 can be considered client premises equipment. A UE 120 can be included in a housing that houses components of the UE 120, such as processor components or memory components. In some examples, the processor components and the memory components can be coupled together. For example, the processor components (e.g., one or more processors) and the memory components (e.g., memory) can be operatively coupled, communicatively coupled, electronically coupled, or electrically coupled.

[0048] In general, any quantity of wireless networks 100 can be deployed in a given geographic area. Each wireless network 100 can support a particular RAT and can operate on one or more frequencies. A RAT can also be referred to as a radio technology, or an air interface. Frequencies can also be referred to as carriers or frequency channels. In some cases, a NR or 5G RAT network can be deployed.

[0049] In some examples, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) can communicate directly using one or more sidelink channels (e.g., without using network node 110 as an intermediary to communicate with one another). For example, UEs 120 can communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, vehicle-to-everything (V2X) protocols (which can include vehicle-to-vehicle (V2V) protocols, vehicle-to-infrastructure (V2I) protocols, or vehicle-to-pedestrian (V2P) protocols), or a mesh network. In such examples, a UE 120 can perform scheduling operations, resource selection operations, or other operations described elsewhere herein as being performed by network node 110.

[0050] Devices of wireless network 100 can communicate using the electromagnetic spectrum, which can be subdivided into various classes, bands, or channels, depending on frequency or wavelength. For example, devices of wireless network 100 can communicate using one or more operating bands. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz - 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as a “sub-6 GHz” band in various documents and articles. A similar nomenclature issue sometimes occurs in connection with FR2, which is often referred to (interchangeably) as a “millimeter wave” band, despite being different from the extremely high frequency (EHF) band (30 GHz - 300 GHz) which is designated as a “millimeter wave” band by the International Telecommunications Union (ITU).

[0051] The frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Recent 5G NR studies have identified operating bands for these mid-band frequencies as frequency range designation FR3 (7.125 GHz - 24.25 GHz). Bands falling within FR3 can inherit FR1 characteristics or FR2 characteristics, and as such can effectively extend the characteristics of FR1 or FR2 into mid-band frequencies. Moreover, higher frequency bands are currently being explored to extend 5G NR operations beyond 52.6 GHz. For example, three higher operating bands have been identified as frequency range designations FR4-a or FR4-1 (52.6 GHz - 71 GHz), FR4 (52.6 GHz - 114.25 GHz), and FR5 (114.25 GHz - 300 GHz). Each of these higher bands falls within the EHF band.

[0052] With the above examples in mind, unless specifically stated otherwise, if the term “sub-6 GHz” is used herein, it can broadly represent frequencies that can be less than 6 GHz, can be within FR1, or can include mid-band frequencies. Moreover, unless specifically stated otherwise, if the term “millimeter wave” is used herein, it can broadly represent frequencies that can include mid-band frequencies, can be within FR2, FR4, FR4-a, or FR4-1, or FR5, or can be within the EHF band. It is contemplated that the frequencies included in these operating bands (e.g., FR1, FR2, FR3, FR4, FR4-a, FR4-1, or FR5) can be modified, and the techniques described herein are applicable to those modified frequency ranges.

[0053] In some respects, UE 120 may include a communication manager 140. As described in more detail elsewhere herein, the communication manager 140 may receive indications of a first TAG associated with a first radio link of the serving cell and a second TAG associated with a second radio link of the serving cell; transmit a first random access channel (RACH) message on the serving cell based at least in part on the failure of a BFR process associated with at least one of the first beam fault detection (BFD) RS sets associated with the first radio link or the second BFD-RS set associated with the second radio link; receive a second RACH message indicating a TAC for the serving cell based at least in part on the transmission of the first RACH message; and communicate with the serving cell based at least in part on the application of the TAC to the first TAG or the second TAG, the application of the TAC to the first TAG or the second TAG being based at least in part on one or more of the following: whether a new candidate beam associated with the first radio link or the second radio link was identified prior to the transmission of the first RACH message; a BFD-RS set in the first BFD-RS set or the second BFD-RS set that is not the at least one BFD-RS set for which a BFR process was not triggered; or an SSB associated with the first RACH message. Additionally or alternatively, the communication manager 140 may perform one or more other operations described herein.

[0054] Figure 2 This is a diagram illustrating communication between an example network node and a UE in a wireless network according to this disclosure. The network node may correspond to... Figure 1 Network node 110. Similarly, the UE can correspond to Figure 1 UE 120. Network node 110 may be equipped with a set of antennas 234a to 234t, such as T antennas (T≥1). UE 120 may be equipped with a set of antennas 252a to 252r, such as R antennas (R≥1). Figure 2 The network node 110 depicted includes one or more radio frequency components, such as antenna 234 and modem 254. In some examples, network node 110 may include an interface, communication components, or another component facilitating communication with UE 120 or another network node. Some network nodes 110 may not include radio frequency components facilitating direct communication with UE 120, such as one or more CUs or one or more DUs.

[0055] At the network node 110, a transmit processor 220 can receive data, from a data source 212, intended for the UE 120 (or a set of UEs 120). The transmit processor 220 can select one or more modulation and coding schemes (MCSs) for the UE 120 based at least in part on one or more channel quality indicators (CQIs) received from the UE 120. The network node 110 can process (e.g., encode and modulate) the data for the UE 120 based at least in part on the MCSs selected for the UE 120 and can provide data symbols for the UE 120. The transmit processor 220 can process system information (e.g., for semi-static resource partitioning information (SRPI)) and control information (e.g., CQI requests, grants, or upper layer signaling) and provide overhead symbols and control symbols. The transmit processor 220 can generate reference symbols for reference signals (e.g., a cell-specific reference signal (CRS) or a demodulation reference signal (DMRS)) and synchronization signals (e.g., a primary synchronization signal (PSS) or a secondary synchronization signal (SSS)). A transmit (TX) multiple-input multiple-output (MIMO) processor 230 can perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, or the reference symbols, if applicable, and can provide output symbol streams (e.g., T output symbol streams) to corresponding modems 232 (e.g., T modems), shown as modems 232a through 232t. Each output symbol stream can be provided to a modulator component (shown as MOD) of the modems 232, for example. Each modem 232 can use a respective modulator component to process a respective output symbol stream (e.g., for OFDM) to obtain an output sample stream. Each modem 232 can also use a respective modulator component to process (e.g., convert to analog, amplify, filter, or upconvert) the output sample stream to obtain a downlink signal. The modems 232a through 232t can transmit the downlink signals (e.g., T downlink signals) via corresponding sets of antennas (e.g., T antennas), shown as antennas 234a through 234t.

[0056] At the UE 120, a set of antennas 252 (shown as antennas 252a through 252r) can receive the downlink signals from network node 110 or other network nodes 110 and can provide a set of received signals (e.g., R received signals) to a set of modems 254 (e.g., R modems), shown as modems 254a through 254r. For example, each received signal can be provided to a demodulator component (shown as DEMOD) of a modem 254. Each modem 254 can condition (e.g., filter, amplify, downconvert, or digitize) a received signal to obtain input samples using a respective demodulator component. Each modem 254 can further process the input samples (e.g., for OFDM) to obtain received symbols using a demodulator component. A MIMO detector 256 can obtain received symbols from modems 254, can perform MIMO detection on the received symbols if applicable, and can provide detected symbols. A receive processor 258 can process (e.g., demodulate and decode) the detected symbols, can provide decoded data for the UE 120 to a data sink 260, and can provide decoded control information and system information to a controller / processor 280. The term “controller / processor” can refer to one or more controllers or one or more processors. The channel processor can determine a reference signal received power (RSRP) parameter, a received signal strength indicator (RSSI) parameter, a reference signal receiving quality (RSRQ) parameter, or a CQI parameter, among other examples. In some examples, one or more components of the UE 120 can be included in a housing.

[0057] Network controller 130 can include communication unit 294, controller / processor 290, and memory 292. Network controller 130 can include, for example, one or more devices in a core network. Network controller 130 can communicate with network node 110 via communication unit 294.

[0058] One or more antennas (e.g., antennas 234a through 234t or antennas 252a through 252r) can include or be included within one or more antenna panels, one or more antenna groups, one or more sets of antenna elements, or one or more antenna arrays, among other examples. An antenna panel, antenna group, set of antenna elements, or antenna array can include one or more antenna elements (within a single housing or multiple housings), a set of co-planar antenna elements, a set of non-co-planar antenna elements, or one or more antenna elements coupled to one or more transmit or receive components (such as one or more components of a transceiver 230 or a modem 254) within a housing. Figure 2 One or more components of a transceiver 230 or a modem 254 can be included in a housing.

[0059] On the uplink, at UE 120, a transmit processor 264 can receive and process data from a data source 262 and control information (e.g., for reports comprising RSRP, RSSI, RSRQ, or CQI) from controller / processor 280. Transmit processor 264 can generate reference symbols for one or more reference signals. The symbols from transmit processor 264 can be precoded by a TX MIMO processor 266 if applicable, further processed by modems 254 (e.g., for DFT-s-OFDM or CP-OFDM), and transmitted to network node 110. In some examples, modems 254 of UE 120 can include modulators and demodulators. In some examples, UE 120 includes a transceiver. The transceiver can include any combination of antenna(s) 252, modems 254, MIMO detector 256, receive processor 258, transmit processor 264, or TX MIMO processor 266. The transceiver can be used by a processor (e.g., controller / processor 280) and memory 282 to perform aspects of any of the methods described herein.

[0060] At network node 110, the uplink signals from UE 120 or other UEs can be received by antennas 234, processed by modems 232 (e.g., demodulator component of modems 232, shown as DEMOD), detected by MIMO detector 236 if applicable, and further processed by receive processor 238 to obtain decoded data and control information transmitted by UE 120. Receive processor 238 can provide the decoded data to data sink 239 and the decoded control information to controller / processor 240. Network node 110 can include communication unit 244 and can communicate with network controller 130 via communication unit 244. Network node 110 can include scheduler 246 to schedule one or more UEs 120 for downlink or uplink communications. In some examples, modems 232 of network node 110 can include modulators and demodulators. In some examples, network node 110 includes a transceiver. The transceiver can include any combination of antenna(s) 234, modems 232, MIMO detector 236, receive processor 238, transmit processor 220, or TX MIMO processor 230. The transceiver can be used by a processor (e.g., controller / processor 240) and memory 242 to perform aspects of any of the methods described herein.

[0061] Controller / processor 240 of network node 110, controller / processor 280 of UE 120, or Figure 2Any other component may perform one or more techniques associated with applying the TAC of the access channel message to a TAG among multiple TAGs, as described in more detail elsewhere herein. For example, the controller / processor 240 of network node 110, the controller / processor 280 of UE 120, or... Figure 2 Any other component can execute or direct, for example Figure 12 The operation of process 1200 or other processes as described herein. Memory 242 and memory 282 may store data and program code for network node 110 and UE 120, respectively. In some examples, memory 242 or memory 282 may include a non-transitory computer-readable medium storing one or more instructions (e.g., code or program code) for wireless communication. For example, one or more instructions may cause one or more processors, UE 120, or network node 110 to perform or direct, for example, when executed by one or more processors of network node 110 or UE 120 (e.g., directly, or after compilation, transformation, or interpretation). Figure 12 The operation of process 1200 or other processes as described herein. In some examples, the execution instructions may include run instructions, transform instructions, compile instructions, or interpret instructions, etc.

[0062] In some aspects, the UE includes components for receiving indications of a first TAG associated with a first radio link of the serving cell and a second TAG associated with a second radio link of the serving cell; components for transmitting a first random access channel (RACH) message on the serving cell based at least in part on the failure of a BFR procedure associated with at least one of a first BFD-RS set associated with the first radio link or a second BFD-RS set associated with the second radio link; components for receiving a second RACH message indicating a TAC for the serving cell based at least in part on transmitting the first RACH message; or components for communicating with the serving cell based at least in part on the application of the TAC to the first TAG or the second TAG, the application of the TAC to the first TAG or the second TAG being based at least in part on one or more of the following: whether a new candidate beam associated with the first radio link or the second radio link was identified prior to the transmission of the first RACH message; a BFD-RS set in the first BFD-RS set or the second BFD-RS set that is not the at least one BFD-RS set for which a BFR procedure was not triggered; or an SSB associated with the first RACH message. Components that enable the UE to perform the operations described herein may include one or more of the following: communication manager 140, antenna 252, modem 254, MIMO detector 256, receive processor 258, transmit processor 264, TX MIMO processor 266, controller / processor 280, or memory 282.

[0063] Deployments of communication systems, such as 5G NR systems, can be arranged in various ways with various components or constituent parts. In a 5G NR system or network, a network node, network entity, mobility element of a network, RAN node, core network node, network element, base station, or network equipment of a network can be implemented in an aggregated or disaggregated architecture. For example, a base station, such as a Node B (NB), an evolved NB (eNB), an NR BS, a 5G NB, an access point (AP), a TRP, or a cell, and so forth, or one or more units (or one or more components) that perform base station functionality can be implemented as an aggregated base station (also referred to as a standalone base station or a monolithic base station) or a disaggregated base station. A “network entity” or “network node” can refer to a disaggregated base station or one or more units of a disaggregated base station, such as one or more CUs, one or more DUs, or one or more RUs.

[0064] An aggregated base station (e.g., an aggregated network node) can be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node (e.g., within a single device or unit). A disaggregated base station (e.g., a disaggregated network node) can be configured to utilize a protocol stack that is physically or logically distributed between two or more units, such as one or more CUs, one or more DUs, or one or more RUs. In some examples, a CU can be implemented within a network node, and one or more DUs can be co-located with the CU or, alternatively, can be geographically or virtually spread throughout one or more other network nodes. The DUs can be implemented to communicate with one or more RUs. Each of the CUs, DUs, and RUs can also be implemented as virtual units, such as a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU), and so forth.

[0065] Base station type operations or network designs can take into account the aggregated nature of base station functionality. For example, a disaggregated base station can be utilized in an IAB network, an open radio access network (O-RAN (such as a network configuration initiated by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also referred to as a cloud radio access network (C-RAN)) to facilitate scaling of a communication system by separating base station functionality into one or more units that can be deployed individually. A disaggregated base station can include functionality implemented across two or more units at various physical locations, as well as functionality implemented virtually for at least one unit, which can enable flexibility in network design. The various units of a disaggregated base station can be configured for wired or wireless communication with at least one other unit of the disaggregated base station.

[0066] Figure 3is a diagram illustrating an example disaggregated base station architecture 300 according to the present disclosure. The disaggregated base station architecture 300 can include a CU 310, which can communicate directly with a core network 320 via a backhaul link, or indirectly through one or more disaggregated control units, such as a near-RT RIC 325 via an E2 link, or a non-RT RIC 315 associated with a service management and orchestration (SMO) framework 305, or both. The CU 310 can communicate with one or more DUs 330 via respective fronthaul links, such as over an Fl interface. Each of the DUs 330 can communicate with one or more RUs 340 via respective front-haul links. Each of the RUs 340 can communicate with one or more UEs 120 via respective radio frequency (RF) access links. In some implementations, a UE 120 can be served by multiple RUs 340 simultaneously.

[0067] Each of the units, including the CU 310, the DUs 330, the RUs 340, as well as the near-RT RIC 325, the non-RT RIC 315, and the SMO framework 305, can include or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via wired or wireless transmission media. Each of the units, or an associated processor or controller providing instructions to one or more communication interfaces of the respective unit, can be configured to communicate with one or more of the other units via the transmission media. In some examples, each of the units can include a wired interface configured to receive or transmit signals to one or more of the other units through a wired transmission medium, and a wireless interface, which can include a receiver, a transmitter, or a transceiver, such as a RF transceiver, configured to receive or transmit signals to one or more of the other units through a wireless transmission medium, or both.

[0068] In some aspects, the CU 310 can host one or more higher layer control functions. Such control functions can include RRC functions, packet data convergence protocol (PDCP) functions, or service data adaptation protocol (SDAP) functions, among other examples. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 310. The CU 310 can be configured to handle user plane functionality (e.g., central unit-user plane (CU-UP) functionality) or control plane functionality (e.g., central unit-control plane (CU-CP) functionality). In some implementations, the CU 310 can be logically divided into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP units can communicate bi-directionally with the CU-CP units via an interface, such as an El interface. The CU 310 can be implemented to communicate with the DUs 330 as needed for network control and signaling.

[0069] Each DU 330 can correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 340. In some aspects, the DU 330 can host one or more of a radio link control (RLC) layer, a MAC layer, and one or more high physical (PHY) layers, at least in part according to a functional split, such as defined by 3GPP. In some aspects, the one or more high PHY layers can be implemented by one or more modules for forward error correction (FEC) encoding and decoding, scrambling, and modulation and demodulation, among other examples. In some aspects, the DU 330 can also host one or more low PHY layers, such as implemented by one or more modules for fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, or physical random access channel (PRACH) extraction and filtering, among other examples. Each layer (which can also be referred to as a module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 330 or with control functions hosted by the CU 310.

[0070] Each RU 340 can implement lower layer functionality. In some deployments, the RUs 340 controlled by the DUs 330 can correspond to logical nodes that host RF processing functions or low PHY layer functions based on a functional split (e.g., a functional split defined by 3GPP), such as a lower layer functional split, such as performing FFT, performing iFFT, digital beamforming, or PRACH extraction and filtering, among other examples. In such an architecture, each RU 340 can be operated to handle over-the-air (OTA) communications with one or more UEs 120. In some implementations, real-time and non-real-time aspects of control plane and user plane communications with the RUs 340 can be controlled by the corresponding DUs 330. In some scenarios, this configuration can enable each DU 330 and CU 310 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

[0071] The SMO framework 305 can be configured to support RAN deployment and provisioning of non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 305 can be configured to support deployment of dedicated physical resources for RAN coverage requirements, which can be managed via an operations and maintenance interface, such as an Ol interface. For virtualized network elements, the SMO framework 305 can be configured to interact with a cloud computing platform, such as an open cloud (O-Cloud) platform 390, to perform network element lifecycle management, such as instantiating virtualized network elements, via a cloud computing platform interface, such as an 02 interface. Such virtualized network elements can include, but are not limited to, the CU 310, the DUs 330, the RUs 340, the non-RT RIC 315, and the near-RT RIC 325. In some implementations, the SMO framework 305 can communicate with hardware aspects of a 4G RAN, such as an open eNB (O-eNB) 311, via an Ol interface. Additionally, in some implementations, the SMO framework 305 can directly communicate with each of the one or more RUs 340 via a respective Ol interface. The SMO framework 305 can also include the non-RT RIC 315, which is configured to support functionality of the SMO framework 305.

[0072] The non-RT RIC 315 can be configured to include logical functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updating, or policy-based steering of applications / features in the near-RT RIC 325. The non-RT RIC 315 can be coupled to, or in communication with, the near-RT RIC 325, such as via an Al interface. The near-RT RIC 325 can be configured to include logical functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface, such as via an E2 interface, that connects one or more CUs 310, one or more DUs 330, or both, and the near-RT RIC 325.

[0073] In some implementations, to generate AI / ML models to be deployed in the near-RT RIC 325, the non-RT RIC 315 can receive parameters or external enrichment information from an external server. Such information can be utilized by the near-RT RIC 325 and can be received at the SMO framework 305 or the non-RT RIC 315 from non-network data sources or from network functions. In some examples, the non-RT RIC 315 or the near-RT RIC 325 can be configured to tune RAN behavior or performance. For example, the non-RT RIC 315 can monitor long-term trends and patterns of performance and employ AI / ML models to perform corrective actions through the SMO framework 305, such as reconfiguration via an Ol interface, or through creation of RAN management policies, such as Al interface policies.

[0074] Figure 4 is a diagram illustrating an example 400 of a beam failure recovery procedure in accordance with the present disclosure. As shown, a UE can be in communication with a network node (e.g., associated with a primary cell), a first TRP associated with a first wireless link to a serving cell, and a second TRP associated with a second wireless link to the serving cell. Figure 4

[0075] As shown in a first operation 405, the UE can detect a beam failure associated with the first TRP and the first wireless link. The BFD can be a per-TRP operation. The associated set of BFD-RSs, set of NBI-RSs, BFD count, and BFD timer can also be per-TPR (e.g., TRP-specific).

[0076] ​In some examples, the UE can identify an implicit BFD-RS set for a multi-DCI communication scheme. For example, the BFD-RS set k (k = 0, 1) can be derived based at least in part on the X TCI of the CORESET, where CORESETPoolIndex = k. If the number of CORESET TCI states per TRP exceeds the UE capability of the maximum number of BFD-RS resources per set, the UE can reuse radio link monitoring (RLM) RS selection rules.

[0077] In some examples, the UE can identify an explicit BFD-RS set for a multi-DCI communication scheme. For example, the explicit BFD-RS set can be configured using radio resource control (RRC) signaling.

[0078] As shown in a second operation 410, the UE can transmit and the network node can receive a physical uplink control channel (PUCCH)-BFR indication associated with the first TRP (BFR_0). In some networks, the UE can select a PUCCH-BFR resource for transmitting the indication. For example, each PUCCH group can be configured with two PUCCH-BFR resources. The UE can select the PUCCH-BFR resource associated with the first TRP (e.g., the TRP associated with the BFD).

[0079] As shown in a third operation 415, the UE can receive and the network node can transmit an uplink grant. The uplink grant can provide the UE with resources for transmitting additional information in a medium access control (MAC) control element (CE).

[0080] As shown in a fourth operation 420, the UE can transmit a BFR MAC CE. The BFR MAC CE can carry a BFR request (BFRQ) for all TRPs in all component carriers in the cell group. The BFRQ can include an index of the failed BFD-RS set (e.g., as an indication of the failed TRP link), an index of the component carrier containing the failed TRP link (e.g., the TRP link for which the beam failure was detected), an indication of whether a new candidate beam is identified in the NBI-RS set associated with the failed BFD-RS set or a resource indicator associated with the new candidate beam (e.g., if identified).

[0081] As shown in a fifth operation 425, the UE can receive and the network node can transmit a BFR response. The BFR response can include an uplink grant that schedules a subsequent transmission of the same hybrid automatic repeat request (HARQ) identifier as the BFR MAC CE.

[0082] As shown in a sixth operation 430, the UE can reset the new beam. For example, the UE and the first TRP can reset the new beam for CORESETs with a CORESETPoolIndex associated with the first TRP. In some networks, after 28 symbols from receiving the BFR response, the beam for all CORESETs associated with the CORESETPoolIndex associated with the first TRP (e.g., the failed TRP) is reset to the reported corresponding new candidate beam.

[0083] As shown in a seventh operation 435, the UE can detect a beam failure associated with the second TRP and the second wireless link. The BFD can be a per-TRP operation. The associated BFD-RS set, NBI-RS set, BFD count, and BFD timer can also be per-TRP (e.g., TRP-specific).

[0084] In some examples, the UE can identify an implicit BFD-RS set for a multi-DCI communication scheme. For example, the BFD-RS set k (k = 0, 1) can be derived based at least in part on the X TCI of the CORESET, where CORESETPoolIndex = k. If the number of CORESET TCI states per TRP exceeds the UE capability of the maximum number of BFD-RS resources per set, the UE can reuse radio link monitoring (RLM) RS selection rules.

[0085] In some examples, the UE can identify an explicit BFD-RS set for a multi-DCI communication scheme. For example, the explicit BFD-RS set can be configured using RRC signaling.

[0086] As shown in an eighth operation 440, the UE can transmit and the network node can receive a PUCCH-BFR indication associated with the second TRP (BFR l). In some networks, the UE can select a PUCCH-BFR resource for transmitting the indication. For example, two PUCCH_BFR resources can be configured per PUCCH group. The UE can select the PUCCH-BFR resource associated with the second TRP (e.g., the TRP associated with the BFD).

[0087] As shown in a ninth operation 445, the UE can receive and the network node can transmit an uplink grant. The uplink grant can provide the UE with resources for transmitting additional information in a MAC CE.

[0088] As shown in a tenth operation 450, the UE can transmit a BFR MAC CE. The BFR MAC CE can carry a BFRQ for all TRPs in all component carriers in the cell group. The BFRQ can include an index of a set of failure BFD-RSs (e.g., as an indication of a failure TRP link), an index of a component carrier containing the failure TRP link (e.g., the TRP link for which beam failure was detected), an indication of whether a new candidate beam is identified in the set of NBI-RSs associated with the set of failure BFD-RSs or a resource indicator associated with the new candidate beam (e.g., if identified).

[0089] As shown in an eleventh operation 455, the UE can receive and the network node can transmit a BFR response. The BFR response can include an uplink grant that schedules a subsequent transmission of the same hybrid automatic repeat request (HARQ) identifier as the BFR MAC CE.

[0090] As shown in a twelfth operation 460, the UE can reset the new beam. For example, the UE and the second TRP can reset the new beam for CORESETs of a CORESET pool index associated with the second TRP. In some networks, after 28 symbols from receiving the BFR response, the beams of all CORESETs associated with the CORESETPoolIndex associated with the second TRP (e.g., the failure TRP) are reset to the reported corresponding new candidate beam.

[0091] In some networks, if a serving cell is configured with two sets of BFD-RSs, if the BFR procedure is triggered for both sets of BFD-RSs for the serving cell (e.g., SpCell), and the BFR procedure is not successfully completed for any set of BFD-RSs, the UE can initiate a random access procedure on the serving cell. Additionally or alternatively, the MAC entity of the UE can initiate a random access procedure on the SpCell and cancel the pending SR, if the MAC entity does not have a valid PUCCH resource configured for the pending SR, for each pending scheduling request as long as at least one SR is pending.

[0092] Figure 5 is a diagram illustrating an example 500 of a four-step random access procedure in accordance with the present disclosure. As shown in Figure 5 the network node 110 and the UE 120 can communicate with each other to perform a four-step random access procedure.

[0093] As shown in first operation 505, network node 110 can transmit and UE 120 can receive one or more SSBs and random access configuration information. In some aspects, the random access configuration information can be transmitted in or indicated by system information (e.g., in one or more system information blocks (SIBs)) or SSBs, such as for contention-based random access. Additionally or alternatively, the random access configuration information can be transmitted in an RRC message or a physical downlink control channel (PDCCH) command message that triggers a RACH procedure, such as for contention-free random access. The random access configuration information can include one or more parameters to be used in a random access procedure, such as one or more parameters for transmitting a RAM or one or more parameters for receiving a RAR.

[0094] As shown in second operation 510, UE 120 can transmit a RAM, which can include a preamble (sometimes referred to as a random access preamble, PRACH preamble, or RAM preamble). The message including the preamble can be referred to as a message 1, msgl, MSG1, first message, or initial message in a four-step random access procedure. The random access message can include a random access preamble identifier.

[0095] As shown in third operation 515, network node 110 can transmit a RAR as a reply to the preamble. The message including the RAR can be referred to as a message 2, msg2, MSG2, or second message in a four-step random access procedure. In some aspects, the RAR can indicate a detected random access preamble identifier (e.g., received from UE 120 in msgl). Additionally or alternatively, the RAR can indicate a resource allocation to be used by UE 120 to transmit a message 3 (msg3).

[0096] In some aspects, as part of a second step of a four-step random access procedure, network node 110 can transmit a PDCCH communication for a RAR. The PDCCH communication can schedule a PDSCH communication including the RAR. For example, the PDCCH communication can indicate a resource allocation for the PDSCH communication. Also as part of the second step of the four-step random access procedure, network node 110 can transmit the PDSCH communication for the RAR as scheduled by the PDCCH communication. The RAR can be included in a MAC PDU of the PDSCH communication. The RAR can include an indication of a TAC for a subsequent communication.

[0097] As shown in fourth operation 520, the UE 120 can transmit a RRC connection request message. The RRC connection request message can be referred to as message 3, msg3, MSG3, or a third message of the four-step random access procedure. In some aspects, the RRC connection request can include a UE identifier, UCI, or a PUSCH communication (e.g., a RRC connection request). The RRC connection request can include an index of a component carrier that includes the failed TRP link. In some examples, the RRC connection request can indicate a failed BFR set identifier, an NBI presence, or an NBI for each TRP (e.g., the first TRP and the second TRP).

[0098] As shown in fifth operation 525, the network node 110 can transmit a RRC connection setup message. The RRC connection setup message can be referred to as message 4, msg4, MSG4, or a fourth message of the four-step random access procedure. In some aspects, the RRC connection setup message can include a detected UE identifier, a timing advance value, or contention resolution information. As shown in sixth operation 530, if the UE 120 successfully receives the RRC connection setup message, the UE 120 can transmit a HARQ ACK.

[0099] Based at least in part on the UE receiving the TAC in msg2 and no indication of which TAG the UE is to apply the TAC to, the UE and the network node can be out of sync. This can result in the UE applying the TAC to an unintended TAG, which can result in the UE and the network node communicating with reduced timing synchronization, increased error rates, and reduced spectral efficiency. Additionally or alternatively, the UE and the network node can consume power, computation, network, and communication resources to detect and correct errors associated with applying the TAC to an unintended TAG.

[0100] Various aspects generally relate to applying a timing advance command (TAC) indicated during a random access procedure to a first TAG or a second TAG. Some aspects more specifically relate to communicating based at least in part on application of the TAC to the first TAG or the second TAG in a multi-transmission reception point (TRP) scenario. In some aspects, a UE can initiate the random access procedure after a beam failure recovery (BFR) procedure fails.

[0101] In some aspects, the UE can apply the TAC to the first TAG based at least in part on failing to identify any new candidate beams for any NBI RS set when transmitting the first random access message. For example, the UE can apply the TAC to the first TAG based at least in part on the first TAG being associated with a first TAG index, a lowest TAG identity relative to a second TAG identity associated with the second TAG, a default CORESET pool index, and / or the like.

[0102] In some aspects, the UE can apply the TAC to the first TAG based at least in part on identifying a new candidate beam in the set of NBI-RS when transmitting the first random access message. For example, the UE can apply the TAC to the first TAG based at least in part on the first TAG being associated with the set of NBI-RS in which the UE identified the new candidate beam.

[0103] In some aspects, the UE can apply the TAC to the first TAG based at least in part on the UE selecting the SSB from the set of NBI-RS associated with the first TAG. In some aspects, the UE can identify a first new candidate beam in a first set of NBI-RS associated with the first TAG and a second new candidate beam in a second set of NBI-RS associated with the second TAG when transmitting the first random access message.

[0104] For example, the UE can apply the TAC to the first TAG based at least in part on the first TAG being associated with the set of NBI-RS to which the selected SSB belongs. The SSB can belong to the set of NBI-RS based at least in part on being received on a beam within the set of NBI-RS.

[0105] In some aspects, the UE can apply the TAC to the first TAG based at least in part on not triggering a BFR procedure for a set of BFD-RS associated with the first TAG. For example, the UE can apply the TAC to the first TAG based at least in part on triggering a BFR procedure for a set of BFD-RS associated with the second TAG.

[0106] In some aspects, the UE can apply the TAC to the first TAG based at least in part on a same CORESET pool index being associated with the first TAG and the SSB associated with the first random access message or the first TAG being associated with the SSB associated with the first random access message.

[0107] Particular aspects of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. In some examples, the described techniques can be used to synchronize application of a TAC to one of multiple TAGs between a UE and a network node, where the TAGs are associated with different TRPs or wireless links of a serving cell. In this way, the UE can apply the TAC to an intended TAG (e.g., intended by the network node) for configuring timing of communications using the intended TAG and associated communication link or beam. Based at least in part on applying the TAC to the intended TAG, the UE and the network node can have improved timing synchronization, reduced error rates, and improved spectral efficiency. In this way, the UE and the network node can conserve power, computation, network, and communication resources that would otherwise be used to detect and correct errors associated with applying the TAC to a non-intended TAG.

[0108] Figure 6 is a diagram illustrating example 600 associated with applying a TAC of an access channel message to a TAG of multiple TAGs according to the present disclosure. As shown, a network node (e.g., network node 110, a CU, a DU, or an RU) can communicate with a UE (e.g., UE 120). In some aspects, the network node and the UE can be part of a wireless network (e.g., wireless network 100). The UE and the network node can have established a wireless connection prior to the operations shown. Figure 6 Figure 6

[0109] As shown in a first operation 605, the network node can transmit, and the UE can receive, configuration information. In some aspects, the UE can receive the configuration information via one or more of RRC signaling, one or more MAC CEs, or downlink control information (DCI), among other examples. In some aspects, the configuration information can include an indication of one or more configuration parameters for the UE to use for selection (e.g., known to the UE or previously indicated by the network node or other network device), explicit configuration information for the UE to use for configuration, or the like.

[0110] In some aspects, the configuration information can indicate an indication of a capability of the UE to transmit a selection of a TAG to which the UE is to apply a TAC received during a random access procedure in a multi-TAG communication scheme. In some aspects, the configuration information can indicate one or more operations or rules for the UE to select a TAG to which the UE is to apply a TAC received during a random access procedure.

[0111] The UE can configure itself based at least in part on the configuration information. In some aspects, the UE can be configured to perform one or more operations described herein based at least in part on the configuration information.

[0112] As shown in a second operation 610, the UE can transmit, and the network node can receive, a capability report. In some aspects, the capability report can indicate that the UE supports selection of a TAG to which the UE is to apply a TAC received during a random access procedure in a multi-TAG communication scheme.

[0113] As shown in a third operation 615, the UE can receive, and the network node can transmit, an RS. The RS can be associated with time synchronization. For example, the RS can include a channel state information reference signal (CSI-RS) or a tracking reference signal (TRS) that the UE can measure to determine timing information. For example, the timing information can include information associated with a propagation delay or a timing advance (TA).

[0114] ​​As shown in a fifth operation 620, the UE can receive and the network node can transmit an indication of a first TAG for a first wireless link and a second TAG for a second wireless link. The first wireless link can be associated with a first TRP and a first CORESET. The second wireless link can be associated with a second TRP and a second CORESET. The first TAG and the second TAG can be nodes of a serving cell.

[0115] In some aspects, the first TAG can be associated with a first set of NBI-RSs or a first set of BFD-RSs, and the second TAG can be associated with a second set of NBI-RSs or a second set of BFD-RSs. In some aspects, the association of a TAG with a set of NBI-RSs or a set of BFD-RSs can be based at least in part on the TAG and the set of NBI-RSs or the set of BFD-RSs being associated with a same CORESET pool index value. In some aspects, the association of a TAG with a set of NBI-RSs or a set of BFD-RSs can be based at least in part on a mapping rule (e.g., in a communication protocol or RRC configuration, among other examples), or the first TAG being configured for the first set of NBI-RSs or the first set of BFD-RSs.

[0116] In some aspects, the first TAG can be configured for the first set of NBI-RSs or in the first set of BFD-RSs based at least in part on the TAG identification of the first TAG to the first set of NBI-RSs or the first set of BFD-RSs or to each RS of the first set of NBI-RSs or the first set of BFD-RSs.

[0117] As shown in a sixth operation 625, the UE can identify a beam failure. For example, the UE can identify a beam failure for the first wireless link, the first TRP, and the first CORESET pool index. Additionally or alternatively, the UE can identify a beam failure for the second wireless link, the second TRP, and the second CORESET pool index.

[0118] As shown in a seventh operation 630, the UE can attempt a BFR procedure associated with at least one set of BFD-RSs from the first set of BFD-RSs associated with the first wireless link or the second set of BFD-RSs associated with the second wireless link. For example, the UE can trigger a BFR procedure and determine whether a resource allows the UE to transmit a PUCCH_BFR0 as described in connection with Figure 4 FIG. 6.

[0119] In some aspects, the BFR procedure can be associated with at least one set of BFD-RSs from the first set of BFD-RSs associated with the first wireless link or the second set of BFD-RSs associated with the second wireless link.

[0120] As shown in the eighth operation 635, the UE can identify or fail to identify one or more new candidate beams. For example, the UE can identify one or more new candidate beams for one BFD-RS set, two BFD-RS sets, or fail to identify one or more new candidate beams for the two BFD-RS sets.

[0121] As shown in the ninth operation 640, the UE can transmit and the network node can receive the first RACH message. In some aspects, the UE can transmit the first RACH message on the serving cell based at least in part on the failure of the BFR procedure.

[0122] As shown in the tenth operation 645, the UE can receive and the network node can transmit the second RACH message indicating the TAC. The TAC can be associated with the serving cell, which is associated with the first TRP and the second TRP.

[0123] As shown in the eleventh operation 650, the UE can apply the TAC to the first TAG or the second TAG.

[0124] In some aspects (e.g., in a case that the UE fails to identify any new candidate beams prior to transmission of the first RACH message), the UE can apply the TAC to the first TAG based at least in part on failing to identify a new candidate beam for any NBI-RS set prior to transmission of the first RACH message and based at least in part on the first TAG being a default TAG. In some aspects, the first TAG can be the default TAG based at least in part on the first TAG being associated with a first TAG index, a lowest TAG identity relative to a second TAG identity associated with a second TAG, or associated with a default CORESET pool index, among other examples.

[0125] In some aspects (e.g., in a case that the UE identifies a new candidate beam for an NBI-RS set prior to transmission of the first RACH message), the UE can apply the TAC to the first TAG based at least in part on the first TAG being associated with the NBI-RS set.

[0126] In some aspects (e.g., in a case that the UE identifies a first new candidate beam for a first NBI-RS set and a second new candidate beam for a second NBI-RS set prior to transmission of the first RACH message), the UE can apply the TAC to the first TAG based at least in part on selecting an SSB associated with a first set of new candidate beams (e.g., a single first new candidate beam) and the first TAG being associated with the first NBI-RS set. In some aspects, the UE can signal the selection of the SSB to the network node (e.g., within the first RACH message).

[0127] In some aspects (e.g., in a case where the application of the TAC to the first TAG or the second TAG is based at least in part on the SSB associated with the first RACH message), the UE can apply the TAC to the first TAG based at least in part on both the first TAG and the SSB associated with the first RACH being associated with a same CORESET pool index or the first TAG being associated with the SSB associated with the first random access message. The CORESET pool index can also be associated with the first TRP and the first wireless link.

[0128] In some aspects (e.g., in a case where the application of the TAC to the first TAG or the second TAG is based at least in part on the SSB associated with the first RACH message), the UE can apply the TAC to the first TAG based at least in part on both the first TAG and the SSB associated with the first RACH being associated with a same CORESET pool index or the first TAG being associated with the SSB associated with the first random access message. The CORESET pool index can also be associated with the first TRP and the first wireless link.

[0129] As shown in twelfth operation 655, the UE and the network node can communicate using the TAC. For example, the UE can communicate with a serving cell associated with the network node based at least in part on the application of the TAC to the first TAG or the second TAG. The application of the TAC to the first TAG or the second TAG can be based at least in part on: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to transmission of the first RACH message; a BFD-RS set of the first BFD-RS set or the second BFD-RS set that is not the at least one BFD-RS set for which a BFR procedure was not triggered; or an SSB associated with the first RACH message, among other examples.

[0130] Based at least in part on applying the TAC to the intended TAG, the UE and the network node can have improved timing synchronization, reduced error rates, and improved spectral efficiency. In this way, the UE and the network node can conserve power, computational, network, and communication resources that would otherwise be used to detect and correct errors associated with applying the TAC to a non-intended TAG.

[0131] Figure 7 is a diagram illustrating an example 700 of a four-step random access procedure in accordance with the present disclosure. As shown in Figure 7 the network node 110 and the UE 120 can communicate with one another to perform a four-step random access procedure.

[0132] As shown in first operation 705, the UE 120 can fail to identify a new candidate beam prior to transmitting a first random access message.

[0133] As shown in a second operation 710, the UE 120 can transmit a RAM, which can include a preamble (sometimes referred to as a random access preamble, a PRACH preamble, or a RAM preamble). The message including the preamble can be referred to as a message 1, msgl, MSG1, first message, or initial message in a four-step random access procedure. The random access message can include a random access preamble identifier.

[0134] As shown in a third operation 715, the network node 110 can transmit a RAR as a reply to the preamble. The message including the RAR can be referred to as a message 2, msg2, MSG2, or second message in a four-step random access procedure. In some aspects, the RAR can indicate a detected random access preamble identifier (e.g., received from the UE 120 in msgl). Additionally or alternatively, the RAR can indicate a resource allocation to be used by the UE 120 to transmit a message 3 (msg3).

[0135] In some aspects, as part of the second step of the four-step random access procedure, the network node 110 can transmit a PDCCH communication for the RAR. The PDCCH communication can schedule a PDSCH communication including the RAR. For example, the PDCCH communication can indicate a resource allocation for the PDSCH communication. Also as part of the second step of the four-step random access procedure, the network node 110 can transmit the PDSCH communication for the RAR as scheduled by the PDCCH communication. The RAR can be included in a MAC PDU of the PDSCH communication. The RAR can include an indication of a TAC for a subsequent communication.

[0136] As shown in a fourth operation 720, the UE 120 can identify a new candidate beam after receiving the RAR. In some aspects, based at least in part on not identifying any new candidate beams for any NBI-RS set when msgl was transmitted, the TAC in the RAR can correspond to a fixed or configured TAG. For example, the TAC can apply to a first TAG of a serving cell (e.g., SpCell), a lowest TAG identifier of a serving cell, or a TAG associated with a CORESETPoolIndex 0.

[0137] As shown in a fifth operation 725, the UE 120 can transmit a RRC connection request message. The RRC connection request message can be referred to as message 3, msg3, MSG3, or a third message of the four-step random access procedure. In some aspects, the RRC connection request can include a UE identifier, UCI, or a PUSCH communication (e.g., a RRC connection request). The RRC connection request can include an index of a component carrier that includes the failed TRP link. In some examples, the RRC connection request can indicate a failed BFR set identifier, an NBI presence, or an NBI for each TRP (e.g., the first TRP and the second TRP).

[0138] As shown in a sixth operation 730, the network node 110 can transmit a RRC connection setup message. The RRC connection setup message can be referred to as message 4, msg4, MSG4, or a fourth message of the four-step random access procedure. In some aspects, the RRC connection setup message can include a detected UE identifier, a timing advance value, or contention resolution information. As shown in a seventh operation 735, if the UE 120 successfully receives the RRC connection setup message, the UE 120 can transmit a HARQ ACK.

[0139] Figure 8 is a diagram illustrating an example 800 of a four-step random access procedure in accordance with the present disclosure. As shown in Figure 8 the network node 110 and the UE 120 can communicate with one another to perform a four-step random access procedure.

[0140] As shown in a first operation 805, the UE 120 can identify a new candidate beam for a first NBI-RS set prior to transmitting a first random access message.

[0141] As shown in a second operation 810, the UE 120 can transmit a RAM, which can include a preamble (sometimes referred to as a random access preamble, a PRACH preamble, or a RAM preamble). The message including the preamble can be referred to as message 1, msgl, MSG1, a first message, or an initial message in the four-step random access procedure. The random access message can include a random access preamble identifier.

[0142] As shown in a third operation 815, the network node 110 can transmit a RAR as a reply to the preamble. The message including the RAR can be referred to as message 2, msg2, MSG2, or a second message in the four-step random access procedure. In some aspects, the RAR can indicate a detected random access preamble identifier (e.g., received from the UE 120 in msgl). Additionally or alternatively, the RAR can indicate a resource allocation to be used by the UE 120 to transmit a message 3 (msg3).

[0143] In some aspects, as part of the second step of the four-step random access procedure, the network node 110 can transmit a PDCCH communication for the RAR. The PDCCH communication can schedule a PDSCH communication that includes the RAR. For example, the PDCCH communication can indicate a resource allocation for the PDSCH communication. Also as part of the second step of the four-step random access procedure, the network node 110 can transmit the PDSCH communication for the RAR as scheduled by the PDCCH communication. The RAR can be included in a MAC PDU of the PDSCH communication. The RAR can include an indication of a TAC for a subsequent communication.

[0144] As shown in fourth operation 820, the UE 120 can identify a new candidate beam for the set of NBI-RSs 2 after receiving the RAR. In some aspects, based at least in part on identifying the new candidate beam for the first set of NBI-RSs before the msgl is transmitted, the TAC in the RAR can correspond to the TAG associated with the first set of NBI-RSs.

[0145] In some aspects, the first TAG can be associated with the first set of NBI-RSs based at least in part on a CORESET pool index (e.g., a CORESETPoolIndex value). For example, the first TAG can be associated with the first set of NBI-RSs based at least in part on the first TAG and the first NBI-RSs being associated with a first CORESET pool index value (e.g., CORESETPoolIndex_0) or the second TAG and the second NBI-RSs being associated with a second CORESET pool index value (e.g., CORESETPoolIndex_l).

[0146] In some aspects, the first TAG can be associated with the first set of NBI-RSs based at least in part on a rule. For example, based at least in part on a rule in a communication protocol or RRC configuration, the first TAG can be associated with the first set of NBI-RSs and the second TAG can be associated with the second set of NBI-RSs. In some aspects, a TAG identifier can be configured for each set of NBI-RSs, or a TAG identifier can be configured for each RS in a set of NBI-RSs. For example, a set of NBI-RSs can be associated with a TAG ID that is associated with the RSs in the set of NBI-RSs.

[0147] As shown in a fifth operation 825, the UE 120 can transmit a RRC connection request message. The RRC connection request message can be referred to as a message 3, msg3, MSG3, or third message of the four-step random access procedure. In some aspects, the RRC connection request can include a UE identifier, UCI, or a PUSCH communication (e.g., RRC connection request). The RRC connection request can include an index of a component carrier that includes the failed TRP link. In some examples, the RRC connection request can indicate a failed BFR set identifier, NBI presence, or NBI for each TRP (e.g., first TRP and second TRP).

[0148] As shown in a sixth operation 830, the network node 110 can transmit a RRC connection setup message. The RRC connection setup message can be referred to as a message 4, msg4, MSG4, or fourth message of the four-step random access procedure. In some aspects, the RRC connection setup message can include a detected UE identifier, a timing advance value, or contention resolution information. As shown in a seventh operation 835, if the UE 120 successfully receives the RRC connection setup message, the UE 120 can transmit a HARQ ACK.

[0149] Figure 9 is a diagram illustrating an example 900 of a four-step random access procedure in accordance with the present disclosure. As shown in Figure 9 the network node 110 and the UE 120 can communicate with each other to perform a four-step random access procedure.

[0150] As shown in a first operation 905, the UE 120 can identify a new candidate beam for a first NBI-RS set and a new candidate beam for a second NBI-RS set prior to transmitting a first random access message.

[0151] As shown in a second operation 910, the UE can select an SSB among the new candidate beams. In some aspects, the new candidate beams are associated with SSBs that satisfy an RSRP threshold (e.g., rsrp-ThresholdSSB), the SSBs associated with the new candidate beams can have a higher RSRP than SSBs outside of the new candidate beams. In some aspects, a TAC in the RAR corresponds to a TAG associated with the first NBI-RS set or the second NBI-RS set to which the selected SSB belongs. In some aspects, the TAG can be associated with the NBI-RS set based at least in part on, for example, one or more foundations described herein.

[0152] As shown in third operation 915, the UE 120 can transmit a RAM, which can include a preamble (sometimes referred to as a random access preamble, a PRACH preamble, or a RAM preamble). The message including the preamble can be referred to as a message 1, msgl, MSG1, first message, or initial message in a four-step random access procedure. The random access message can include a random access preamble identifier.

[0153] As shown in fourth operation 920, the network node 110 can transmit a RAR as a reply to the preamble. The message including the RAR can be referred to as a message 2, msg2, MSG2, or second message in a four-step random access procedure. In some aspects, the RAR can indicate a detected random access preamble identifier (e.g., received from the UE 120 in msgl). Additionally or alternatively, the RAR can indicate a resource allocation to be used by the UE 120 to transmit a message 3 (msg3).

[0154] In some aspects, as part of the second step of the four-step random access procedure, the network node 110 can transmit a PDCCH communication for the RAR. The PDCCH communication can schedule a PDSCH communication including the RAR. For example, the PDCCH communication can indicate a resource allocation for the PDSCH communication. Also as part of the second step of the four-step random access procedure, the network node 110 can transmit the PDSCH communication for the RAR as scheduled by the PDCCH communication. The RAR can be included in a MAC PDU of the PDSCH communication. The RAR can include an indication of a TAC for a subsequent communication.

[0155] As shown in fifth operation 925, the UE 120 can transmit an RRC connection request message. The RRC connection request message can be referred to as a message 3, msg3, MSG3, or third message of the four-step random access procedure. In some aspects, the RRC connection request can include a UE identifier, UCI, or a PUSCH communication (e.g., the RRC connection request). The RRC connection request can include an index of a component carrier that includes the failed TRP link. In some examples, the RRC connection request can indicate, for each TRP (e.g., the first TRP and the second TRP), a failed BFR set identifier, an NBI presence, or an NBI.

[0156] As shown in sixth operation 930, the network node 110 can transmit an RRC connection setup message. The RRC connection setup message can be referred to as a message 4, msg4, MSG4, or fourth message of the four-step random access procedure. In some aspects, the RRC connection setup message can include a detected UE identifier, a timing advance value, or contention resolution information. As shown in seventh operation 935, if the UE 120 successfully receives the RRC connection setup message, the UE 120 can transmit a HARQ ACK.

[0157] Figure 10 is a diagram illustrating an example 1000 of a four-step random access procedure according to the present disclosure. As shown, network node 110 and UE 120 can communicate with one another to perform a four-step random access procedure. Figure 10

[0158] As shown in first operation 1005, UE 120 can trigger a BFR procedure for a first set of BFD-RSs. For example, the UE can trigger a CBRA and can trigger a BFR procedure for one set of BFD-RSs of a serving cell. In this case, the TAC in the RAR can correspond to a TAG associated with the set of faultless BFD-RSs. For example, the UE can trigger a BFR procedure for a second wireless link associated with a second TAG. In this case, the TAC can apply to a first TAG associated with a first wireless link for which the BFR procedure is not triggered.

[0159] In some aspects, the association between a TAG and a set of BFD-RSs can be determined based on an association between the TAG and a set of NBI-RSs and an association between the set of BFD-RSs and the set of NBI-RSs. In some aspects, the association between a TAG and a set of BFD-RSs can be defined based at least in part on a rule or configuration. In some aspects, a first TAG can be associated with a first set of BFD-RSs based at least in part on a CORESET pool index (e.g., a CORESETPoolIndex value). For example, the first TAG can be associated with the first set of BFD-RSs based at least in part on the first TAG and the first BFD-RS being associated with a first CORESET pool index value (e.g., CORESETPoolIndex_0) or the second TAG and the second BFD-RS being associated with a second CORESET pool index value (e.g., CORESETPoolIndex_1).

[0160] For example, a first TAG can be associated with a first set of BFD-RSs based at least in part on a rule. For example, based at least in part on a rule in a communication protocol or RRC configuration, a first TAG can be associated with a first set of BFD-RSs and a second TAG can be associated with a second set of BFD-RSs. In some aspects, a TAG identifier can be configured for each set of BFD-RSs or a TAG identifier can be configured for each RS in a set of BFD-RSs. For example, a set of BFD-RSs can be associated with a TAG ID that is associated with a RS in the set of BFD-RSs.

[0161] ​As shown in a second operation 1010, the UE 120 can transmit a RAM, which can include a preamble (sometimes referred to as a random access preamble, a PRACH preamble, or a RAM preamble). The message including the preamble can be referred to as a message 1, msgl, MSG1, first message, or initial message in a four-step random access procedure. The random access message can include a random access preamble identifier.

[0162] As shown in a third operation 1015, the network node 110 can transmit a RAR as a reply to the preamble. The message including the RAR can be referred to as a message 2, msg2, MSG2, or second message in a four-step random access procedure. In some aspects, the RAR can indicate a detected random access preamble identifier (e.g., received from the UE 120 in msgl). Additionally or alternatively, the RAR can indicate a resource allocation to be used by the UE 120 to transmit a message 3 (msg3).

[0163] In some aspects, as part of the second step of the four-step random access procedure, the network node 110 can transmit a PDCCH communication for the RAR. The PDCCH communication can schedule a PDSCH communication including the RAR. For example, the PDCCH communication can indicate a resource allocation for the PDSCH communication. Also as part of the second step of the four-step random access procedure, the network node 110 can transmit the PDSCH communication for the RAR as scheduled by the PDCCH communication. The RAR can be included in a MAC PDU of the PDSCH communication. The RAR can include an indication of a TAC for a subsequent communication.

[0164] As shown in a fourth operation 1020, the UE 120 can transmit an RRC connection request message. The RRC connection request message can be referred to as a message 3, msg3, MSG3, or third message in a four-step random access procedure. In some aspects, the RRC connection request can include a UE identifier, UCI, or a PUSCH communication (e.g., the RRC connection request). The RRC connection request can include an index of a component carrier that includes the failed TRP link. In some examples, the RRC connection request can indicate a failed BFR set identifier, an NBI presence, or an NBI for each TRP (e.g., the first TRP and the second TRP).

[0165] As shown in a fifth operation 1025, the network node 110 can transmit an RRC connection setup message. The RRC connection setup message can be referred to as message 4, msg4, MSG4, or a fourth message of the four-step random access procedure. In some aspects, the RRC connection setup message can include the detected UE identifier, the timing advance value, or the contention resolution information. As shown in a sixth operation 1030, if the UE 120 successfully receives the RRC connection setup message, the UE 120 can transmit a HARQ ACK.

[0166] Figure 11 is a diagram illustrating an example 1100 of a four-step random access procedure in accordance with the present disclosure. As shown in Figure 11 the network node 110 and the UE 120 can communicate with one another to perform the four-step random access procedure.

[0167] As shown in a first operation 1105, the UE 120 can select an SSB for the random access procedure. The UE can trigger the random access procedure based at least in part on a failure of a BFR procedure or an expiration of a time alignment timer, among other examples. In some aspects, a TAC in the RAR can correspond to the first TAG based at least in part on the first TAG being associated with the SSB selected for the random access procedure.

[0168] For example, the TAC in the RAR can correspond to the first TAG based at least in part on being associated with a same CORESET pool index as the selected SSB for CBRA. In some aspects, the TAC in the RAR corresponds to the first TAG based at least in part on being associated with the selected SSB (e.g., if a TAG ID is associated or configured for each SSB).

[0169] As shown in a second operation 1110, the UE 120 can transmit a RAM, which can include a preamble (sometimes referred to as a random access preamble, a PRACH preamble, or a RAM preamble). The message including the preamble can be referred to as message 1, msgl, MSG1, a first message, or an initial message in the four-step random access procedure. The random access message can include a random access preamble identifier.

[0170] As shown in a third operation 1115, the network node 110 can transmit a RAR as a reply to the preamble. The message including the RAR can be referred to as message 2, msg2, MSG2, or a second message in the four-step random access procedure. In some aspects, the RAR can indicate the detected random access preamble identifier (e.g., received from the UE 120 in msgl). Additionally or alternatively, the RAR can indicate a resource allocation to be used by the UE 120 to transmit a message 3 (msg3).

[0171] In some respects, as part of the second step of the four-step random access procedure, network node 110 may send PDCCH communication for the RAR. This PDCCH communication may schedule PDSCH communication including the RAR. For example, the PDCCH communication may indicate resource allocation for the PDSCH communication. Also as part of the second step of the four-step random access procedure, network node 110 may send PDSCH communication for the RAR, as scheduled by the PDCCH communication. The RAR may be included in the MAC PDU of the PDSCH communication. The RAR may include an indication of a TAC for subsequent communication.

[0172] As shown in operation 1120, UE 120 may send an RRC connection request message. The RRC connection request message may be referred to as message 3, msg3, MSG3, or the third message of the four-step random access procedure. In some aspects, the RRC connection request may include a UE identifier, UCI, or PUSCH communication (e.g., RRC connection request). The RRC connection request may include an index of a component carrier that includes a faulty TRP link. In some examples, the RRC connection request may indicate a faulty BFR set identifier, NBI presence, or NBI for each TRP (e.g., the first TRP and the second TRP).

[0173] As shown in the fifth operation 1125, network node 110 may send an RRC connection establishment message. The RRC connection establishment message may be referred to as message 4, msg4, MSG4, or the fourth message in the four-step random access procedure. In some aspects, the RRC connection establishment message may include the detected UE identifier, timing advance value, or contention resolution information. As shown in the sixth operation 1130, if UE 120 successfully receives the RRC connection establishment message, UE 120 may send a HARQ ACK.

[0174] Figure 12 This is a flowchart illustrating an example procedure 1200 performed by a UE that supports selecting a TAG in a multi-TAG communication scheme, according to this disclosure, in which the UE applies a TAC received during a random access procedure to that TAG. Example procedure 1200 is an example in which a UE (e.g., UE 120) performs an operation associated with applying a TAC of an access channel message to one of a plurality of TAGs.

[0175] like Figure 12 As shown, in some aspects, process 1200 may include receiving indications of a first TAG associated with a first radio link of the serving cell and a second TAG associated with a second radio link of the serving cell (block 1210). For example, a UE (such as by using...) Figure 13The communication manager 140 or the reception component 1302 depicted in FIG. 13 can receive an indication of a first TAG associated with a first wireless link of a serving cell and a second TAG associated with a second wireless link, as described above.

[0176] As Figure 12 Further as shown, in some aspects, process 1200 can include transmitting a first random access channel (RACH) message on the serving cell based at least in part on a failure of a BFR procedure associated with at least one of a first set of BFD-RSs associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link (block 1220). For example, the UE, such as by using Figure 13 The communication manager 140 or the transmission component 1304 depicted in FIG. 13 can transmit a first random access channel (RACH) message on the serving cell based at least in part on a failure of a BFR procedure associated with at least one of a first set of BFD-RSs associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link, as described above.

[0177] As Figure 12 Further as shown, in some aspects, process 1200 can include receiving a second RACH message indicating a TAC for the serving cell based at least in part on transmitting the first RACH message (block 1230). For example, the UE, such as by using Figure 13 The communication manager 140 or the reception component 1302 depicted in FIG. 13 can receive a second RACH message indicating a TAC for the serving cell based at least in part on transmitting the first RACH message, as described above.

[0178] As Figure 12 Further as shown, in some aspects, process 1200 can include communicating with the serving cell based at least in part on an application of the TAC to the first TAG or the second TAG based at least in part on one or more of: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to transmission of the first RACH message; a set of BFD-RSs of the first set of BFD-RSs or the second set of BFD-RSs that is not the at least one set of BFD-RSs for which a BFR procedure was not triggered; or an SSB associated with the first RACH message (block 1240). For example, the UE, such as by using Figure 13The communication manager 140, reception component 1302, or transmission component 1304 (as depicted in the example of FIG. 13) can include communicating with the serving cell based at least in part on the application of the TAC to the first TAG or the second TAG based at least in part on one or more of: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to transmission of the first RACH message; a set of BFD-RSs in the first set of BFD-RSs or the second set of BFD-RSs that is not the set of BFD-RSs for which a BFR procedure is triggered; or a SSB associated with the first RACH message, as described above.

[0179] Process 1200 can include additional aspects, such as any single aspect or any combination of aspects described below or in connection with one or more other processes described elsewhere herein.

[0180] In a first additional aspect, the first TAG is associated with a set of new beam identification RSs (NBI-RSs) or the first set of BFD-RSs based at least in part on one or more of: at least one of the set of NBI-RSs or the first set of BFD-RSs and the first TAG being associated with a same CORESET pool index value; a mapping rule, or the first TAG being configured for the set of NBI-RSs or the first set of BFD-RSs.

[0181] In a second additional aspect, alone or in combination with the first aspect, the first TAG is configured for the first set of NBI-RSs or in the first set of BFD-RSs based at least in part on a TAG identification of the first TAG to the first set of NBI-RSs or the first set of BFD-RSs or to a configuration of each RS in the first set of NBI-RSs or the first set of BFD-RSs.

[0182] In a third additional aspect, alone or in combination with one or more of the first and second aspects, process 1200 includes failing to identify a new candidate beam for any set of NBI-RSs prior to transmission of the first RACH message, where the application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beam was identified prior to transmission of the first RACH message, and where the application of the TAC to the first TAG is based at least in part on the first TAG being a default TAG.

[0183] In a fourth additional aspect, alone or in combination with one or more of the first through third aspects, the first TAG is a default TAG based at least in part on the first TAG being associated with a first TAG index associated with the first TAG, a lowest TAG identity relative to a second TAG identity associated with a second TAG, or a default CORESET pool index.

[0184] In a fifth additional aspect, alone or in combination with one or more of the first through fourth aspects, the process 1200 includes identifying a new candidate beam for the set of NBI-RSs prior to transmission of the first RACH message, where application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beam is identified prior to transmission of the first RACH message, and where the TAC is applied to the first TAG based at least in part on the first TAG being associated with the set of NBI-RSs.

[0185] In a sixth additional aspect, alone or in combination with one or more of the first through fifth aspects, the process 1200 includes identifying a first set of new candidate beams for the first set of NBI-RSs and a second set of new candidate beams for the second set of NBI-RSs prior to transmission of the first RACH message, and selecting an SSB associated with the first set of new candidate beams or the second set of new candidate beams, where application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beams are identified prior to transmission of the first RACH message, and where the TAC is applied to the first TAG based at least in part on the selected SSB being within the first set of candidate beams and the first TAG being associated with the first set of NBI-RSs.

[0186] In a seventh additional aspect, alone or in combination with one or more of the first through sixth aspects, application of the TAC to the first TAG or the second TAG is based at least in part on a BFD-RS set of the first set of BFD-RSs or the second set of BFD-RSs that is not the at least one BFD-RS set for which a BFR procedure is not triggered, where the at least one BFD-RS set is associated with the first TAG and the BFD-RS set that is not the at least one BFD-RS set is associated with the second TAG, and where the TAC is applied to the second TAG based at least in part on the BFD-RS set being associated with the second TAG.

[0187] In an eighth additional aspect, alone or in combination with one or more of the first through seventh aspects, application of the TAC to the first TAG or the second TAG is based at least in part on an SSB associated with the first RACH message, where the SSB and the first TAG are associated with a same CORESET pool index, and where the TAC is applied to the first TAG based at least in part on the SSB and the first TAG being associated with the same CORESET pool index.

[0188] In the ninth additional aspect, either alone or in combination with one or more of the first to eighth aspects, the application of TAC to the first TAG or the second TAG is based at least in part on the SSB associated with the first RACH message, wherein the first TAG is associated with the SSB, and wherein the TAC is applied to the first TAG based at least in part on the first TAG being associated with the SSB.

[0189] In the tenth additional aspect, either alone or in combination with one or more of the first to ninth aspects, the first TAG is associated with communication with the first network node, and wherein the second TAG is associated with communication with the second network node.

[0190] In the eleventh additional aspect, alone or in combination with one or more of the first to tenth aspects, process 1200 includes identifying beam faults for at least one BFD-RS set that triggers the transmission of the first RACH message.

[0191] Although Figure 12 The example box for process 1200 is shown, but in some respects, it differs from... Figure 12 Compared to those depicted, process 1200 may include additional boxes, fewer boxes, different boxes, or boxes arranged differently. Additionally or alternatively, two or more boxes in process 1200 may be executed in parallel.

[0192] Figure 13 This is a diagram of an example device 1300 for wireless communication according to the present disclosure. Device 1300 may be a UE, or a UE may include device 1300. In some aspects, device 1300 includes a receiving component 1302 and a transmitting component 1304 that can communicate with each other (e.g., via one or more buses or one or more other components). As shown, device 1300 can use the receiving component 1302 and the transmitting component 1304 to communicate with another device 1306 (such as a UE, a base station, or another wireless communication device). As further shown, device 1300 may include a communication manager (e.g., communication manager 140).

[0193] In some respects, device 1300 can be configured to perform the actions described herein. Figures 6 to 11 One or more operations described herein. Additionally or alternatively, the apparatus 1300 may be configured to perform one or more processes described herein, such as Figure 12 The process 1200. In some respects, the apparatus 1300 or Figure 13 One or more components shown may include combinations Figure 2 One or more components of the UE described. Additionally or alternatively, Figure 13 One or more components shown can be combined Figure 2implementation within one or more components. Additionally or alternatively, one or more components of a collection of components can be implemented at least partially as software stored in a memory. For example, a component (or a portion of a component) can be implemented as instructions or code stored in a non-transitory computer-readable medium and executable by a controller or a processor to perform the functions or operations of that component.

[0194] The reception component 1302 can receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus 1306. The reception component 1302 can provide received communications to one or more other components of the apparatus 1300. In some aspects, the reception component 1302 can perform signal processing on the received communications (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, de-mapping, equalization, interference cancellation, or decoding, among other examples), and can provide the processed signals to the one or more other components of the apparatus 1300. In some aspects, the reception component 1302 can include one or more antennas, a modem, a MIMO detector, a receive processor, a controller / processor, a memory, or a combination thereof, of the UE described above. Figure 2 The described UE one or more antennas, a modem, a demodulator, a MIMO detector, a receive processor, a controller / processor, a memory, or a combination thereof.

[0195] The transmission component 1304 can transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus 1306. In some aspects, one or more other components of the apparatus 1300 can generate communications and can provide the generated communications to the transmission component 1304 for transmission to the apparatus 1306. In some aspects, the transmission component 1304 can perform signal processing on the generated communications (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding, among other examples), and can transmit the processed signals to the apparatus 1306. In some aspects, the transmission component 1304 can include one or more antennas, a modem, a transmit MIMO processor, a transmit processor, a controller / processor, a memory, or a combination thereof, of the UE described above. In some aspects, the transmission component 1304 can be co-located with the reception component 1302 in a transceiver. Figure 2 The described UE one or more antennas, a modem, a demodulator, a MIMO detector, a receive processor, a controller / processor, a memory, or a combination thereof.

[0196] The reception component 1302 can receive an indication of a first TAG associated with a first wireless link of a serving cell and a second TAG associated with a second wireless link of the serving cell. The transmission component 1304 can transmit, on the serving cell, a first random access channel (RACH) message based at least in part on a failure of a BFR procedure associated with at least one of a first set of BFD-RSs associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link. The reception component 1302 can receive, based at least in part on transmitting the first RACH message, a second RACH message indicating a TAC for the serving cell. The reception component 1302 or the transmission component 1304 can communicate with the serving cell based at least in part on application of the TAC to the first TAG or the second TAG based at least in part on one or more of: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to transmission of the first RACH message; a set of BFD-RSs of the first set of BFD-RSs or the second set of BFD-RSs that is not the at least one set of BFD-RSs for which a BFR procedure was not triggered; or an SSB associated with the first RACH message.

[0197] The communication manager 1308 can fail to identify a new candidate beam for any set of NBI-RSs prior to transmission of the first RACH message, where the application of the TAC to the first TAG or the second TAG is based at least in part on whether a new candidate beam was identified prior to transmission of the first RACH message, and where the application of the TAC to the first TAG is based at least in part on the first TAG being a default TAG.

[0198] The communication manager 1308 can identify a new candidate beam for a set of NBI-RSs prior to transmission of the first RACH message, where the application of the TAC to the first TAG or the second TAG is based at least in part on whether a new candidate beam was identified prior to transmission of the first RACH message, and where the TAC is applied to the first TAG based at least in part on the first TAG being associated with the set of NBI-RSs.

[0199] The communication manager 1308 can identify a first set of new candidate beams for a first set of NBI-RSs and a second set of new candidate beams for a second set of NBI-RSs prior to transmission of the first RACH message.

[0200] The communications manager 1308 can select an SSB associated with the first set of new candidate beams or the second set of new candidate beams, where application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beams were identified prior to transmitting the first RACH message, and where the TAC is applied to the first TAG based at least in part on the selected SSB being within the first set of candidate beams and the first TAG being associated with the first set of NBI-RSs.

[0201] The communications manager 1308 can identify a beam failure for the at least one set of BFD-RSs that triggered transmission of the first RACH message.

[0202] Figure 13 The number and arrangement of components shown is provided as an example. In practice, there can be additional components, fewer components, different components, or differently arranged components than those shown. Figure 13 Additionally, or alternatively, Figure 13 Two or more components shown can be implemented within a single component, or Figure 13 A single component shown can be implemented as multiple, distributed components. Additionally or alternatively, Figure 13 A set of one or more components shown can perform one or more functions described as being performed by Figure 13 Another set of components.

[0203] An overview of some aspects of the disclosure is provided below:

[0204] Aspect 1 : A method of wireless communication performed by a user equipment (UE), the method comprising: receiving an indication of a first timing advance group (TAG) associated with a first wireless link of a serving cell and a second TAG associated with a second wireless link of the serving cell; transmitting, on the serving cell, a first random access channel (RACH) message based at least in part on a failure of a beam failure recovery (BFR) procedure associated with at least one of a first set of beam failure detection (BFD) reference signals (RSs) associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link; receiving a second RACH message indicating a timing advance command (TAC) for the serving cell based at least in part on transmitting the first RACH message; and communicating with the serving cell based at least in part on an application of the TAC to the first TAG or the second TAG, the application of the TAC to the first TAG or the second TAG based at least in part on one or more of: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to the transmission of the first RACH message; a set of BFD-RSs of the first set of BFD-RSs or the second set of BFD-RSs that is not the at least one set of BFD-RSs for which the BFR procedure was triggered; or a synchronization signal block (SSB) associated with the first RACH message.

[0205] Aspect 2: The method of aspect 1, wherein the first TAG is associated with a new beam identification RS (NBI-RS) set or the first set of BFD-RSs based at least in part on one or more of: at least one of the NBI-RS set or the first set of BFD-RSs and the first TAG being associated with a same control resource set (CORESET) pool index value; a mapping rule; or the first TAG being configured for the NBI-RS set or the first set of BFD-RSs.

[0206] Aspect 3: The method of aspect 2, wherein the first TAG is configured for the first NBI-RS set or in the first set of BFD-RSs based at least in part on a configuration of a TAG identification of the first TAG to: the first NBI-RS set or the first set of BFD-RSs, or each RS of the first NBI-RS set or the first set of BFD-RSs.

[0207] Aspect 4: The method of any of aspects 1 through 3, further comprising failing to identify the new candidate beam for any new beam identification RS (NBI-RS) set prior to the transmission of the first RACH message, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beam was identified prior to the transmission of the first RACH message, and wherein the application of the TAC to the first TAG is based at least in part on the first TAG being a default TAG.

[0208] Aspect 5: The method of aspect 4, wherein the first TAG is a default TAG based at least in part on the first TAG being associated with: a first TAG index associated with a first TAG; a lowest TAG identity relative to a second TAG identity associated with the second TAG; or a default control resource set (CORESET) pool index.

[0209] Aspect 6: The method of any of aspects 1 through 5, further comprising identifying the new candidate beam for a new beam identification RS (NBI-RS) set prior to the transmission of the first RACH message, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beam was identified prior to the transmission of the first RACH message, and wherein the TAC is applied to the first TAG based at least in part on the first TAG being associated with the NBI-RS set.

[0210] Aspect 7: The method of any of aspects 1 through 6, further comprising: identifying a first set of new candidate beams for a first new beam identification RS (NBI-RS) set and a second set of new candidate beams for a second NBI-RS set prior to the transmission of the first RACH message; and selecting a synchronization signal block (SSB) associated with the first set of new candidate beams or the second set of new candidate beams, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beam was identified prior to transmitting the first RACH message, and wherein the TAC is applied to the first TAG based at least in part on the selected SSB being within the first set of candidate beams and the first TAG being associated with the first NBI-RS set.

[0211] Aspect 8: The method of any of aspects 1 through 7, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on a set of BFD-RSs of the first set of BFD-RSs or the second set of BFD-RSs for which the BFR procedure is not triggered, wherein the at least one set of BFD-RSs is associated with the first TAG and the set of BFD-RSs that is not the at least one set of BFD-RSs is associated with the second TAG, and wherein the TAC is applied to the second TAG based at least in part on the set of BFD-RSs being associated with the second TAG.

[0212] Aspect 9: The method of any of aspects 1 through 8, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on the SSB associated with the first RACH message, wherein the SSB and the first TAG are associated with a same control resource set (CORESET) pool index, and wherein the TAC is applied to the first TAG based at least in part on the SSB and the first TAG being associated with the same CORESET pool index.

[0213] Aspect 10: The method of any of aspects 1 through 9, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on the SSB associated with the first RACH message, wherein the first TAG is associated with the SSB, and wherein the TAC is applied to the first TAG based at least in part on the first TAG being associated with the SSB.

[0214] Aspect 11: The method of any of aspects 1 through 10, wherein the first TAG is associated with communications with a first network node, and wherein the second TAG is associated with communications with a second network node.

[0215] Aspect 12: The method of any of aspects 1 through 11, further comprising identifying a beam failure for the at least one set of BFD-RSs that triggered the transmission of the first RACH message.

[0216] Aspect 13: An apparatus for wireless communication at a device, the apparatus comprising: a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any of aspects 1 through 12.

[0217] Aspect 14: An apparatus for wireless communication, comprising a memory and one or more processors coupled to the memory, the one or more processors configured to perform the method of any of aspects 1 through 12.

[0218] Aspect 15: An apparatus for wireless communication, comprising at least one means for performing the method of any of aspects 1 through 12.

[0219] Aspect 16: A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform the method of any of aspects 1 through 12.

[0220] Aspect 17: A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising one or more instructions that, when executed by one or more processors of an apparatus, cause the apparatus to perform the method of any of aspects 1 through 12.

[0221] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations can be made in light of the above disclosure or can be acquired from practice of the aspects.

[0222] As used herein, the term “component” is intended to be broadly interpreted to encompass hardware or a combination of hardware and software. “Software” shall be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, or functions, among other examples, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. As used herein, a “processor” is implemented in hardware or a combination of hardware and software. The systems or methods described herein can be implemented in various forms and the particular form chosen to implement the systems or methods will be evident from the description given herein. The actual specialized control hardware or software code used to implement the systems or methods is not limiting of the aspects. Thus, the operation and behavior of the systems or methods are described herein without reference to the specific software code— it being understood that software and hardware can be designed to implement the systems or methods based, at least in part, on the description herein.

[0223] As used herein, depending on the context, “satisfy a threshold” can refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, and the like.

[0224] Although features of a combination can be expressed or disclosed in the specification or claims in a particular combination, those combinations are not intended to be limiting, and features of one combination can be used in combination with features of another combination. The disclosure of a feature or aspect under an embodiment with the phrase “at least one” does not foreclose the existence of “only one” of that feature or aspect. The disclosure of features or aspects in the specification or claims can also include features or aspects that are not explicitly stated or otherwise explicitly disclosed. The disclosure of a class of features or aspects under an embodiment is a disclosure of each member of the class and all combinations of the members. The disclosure of features or aspects in the specification and claims can also include features or aspects that are neither parallel nor mutually exclusive, overlapping or separate.

[0225] No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items, and can be used interchangeably with “one or more.” Furthermore, as used herein, the article “the” is intended to include one or more items, and can be used interchangeably with “the one or more.” Also, as used herein, the term “set” and “group” is intended to include one or more items, and can be used interchangeably with “one or more.” If only one item is intended, the phrase “only one” or similar language will be used. Also, as used herein, the term “has,” and its variants are intended to be an open-ended term, and does not exclude the presence of more than one item. Also, as used herein, the phrase “based on” is intended to be open-ended, and specifically does not exclude the presence of more than one item in the item being based on. Also, as used herein, the term “or” when used in a list of two or more items, is intended to be inclusive, and specifically the list is intended to be interpreted as “one or more” of the elements.

Claims

1. A user equipment (UE) for wireless communication, the user equipment (UE) comprising: a memory; and one or more processors coupled to the memory, the one or more processors configured to: receive an indication of a first timing advance group (TAG) associated with a first wireless link of a serving cell and a second TAG associated with a second wireless link of the serving cell; transmit, on the serving cell, a first random access channel (RACH) message based at least in part on a failure of a beam failure recovery (BFR) procedure associated with at least one of a first set of beam failure detection (BFD) reference signals (RSs) associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link; receive, based at least in part on transmitting the first RACH message, a second RACH message indicating a timing advance command (TAC) for the serving cell; and communicate with the serving cell based at least in part on an application of the TAC to the first TAG or the second TAG, the application of the TAC to the first TAG or the second TAG based at least in part on one or more of: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to the transmission of the first RACH message, a set of BFD-RSs of the first set of BFD-RSs or the second set of BFD-RSs that is not the at least one set of BFD-RSs for which the BFR procedure was triggered, or a synchronization signal block (SSB) associated with the first RACH message.

2. The UE of claim 1, wherein the first TAG is associated with a new beam identification RS (NBI-RS) set or the first set of BFD-RSs based at least in part on one or more of: at least one of the NBI-RS set or the first set of BFD-RSs and the first TAG being associated with a same control resource set (CORESET) pool index value, a mapping rule, or the first TAG being configured for the NBI-RS set or the first set of BFD-RSs.

3. The UE of claim 2, wherein the first TAG is configured for the NBI-RS set or in the first set of BFD-RSs based at least in part on a configuration of a TAG identification of the first TAG to: the NBI-RS set or the first set of BFD-RSs, or each RS of the NBI-RS set or the first set of BFD-RSs.

4. The UE of claim 1, wherein the one or more processors are further configured to fail to identify the new candidate beam for any new beam identification RS (NBI-RS) set prior to the transmission of the first RACH message, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beam is identified prior to the transmission of the first RACH message, and wherein the application of the TAC to the first TAG is based at least in part on the first TAG being a default TAG.

5. The UE of claim 4, wherein the first TAG is a default TAG based at least in part on the first TAG being associated with: a first TAG index, a lowest TAG identity relative to a second TAG identity associated with the second TAG, or a default control resource set (CORESET) pool index.

6. The UE of claim 1, wherein the one or more processors are further configured to identify the new candidate beam for a set of new beam identification RSs (NBI-RSs) prior to the transmission of the first RACH message, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beam is identified prior to the transmission of the first RACH message, and wherein the TAC is applied to the first TAG based at least in part on the first TAG being associated with the set of NBI-RSs.

7. The UE of claim 1, wherein the one or more processors are further configured to: identify, prior to the transmission of the first RACH message, a first set of new candidate beams for a first set of new beam identification RSs (NBI-RSs) and a second set of new candidate beams for a second set of NBI-RSs; and select a synchronization signal block (SSB) associated with the first set of new candidate beams or the second set of new candidate beams, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beam is identified prior to transmitting the first RACH message, and wherein the TAC is applied to the first TAG based at least in part on the selected SSB being within the first set of candidate beams and the first TAG being associated with the first set of NBI-RSs.

8. The UE of claim 1, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on a BFD-RS set of the first BFD-RS set or the second BFD-RS set for which the BFR procedure is not triggered, wherein the at least one BFD-RS set is associated with the first TAG and the BFD-RS set that is not the at least one BFD-RS set is associated with the second TAG, and wherein the TAC is applied to the second TAG based at least in part on the BFD-RS set being associated with the second TAG.

9. The UE of claim 1, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on the SSB associated with the first RACH message, wherein the SSB and the first TAG are associated with a same control resource set (CORESET) pool index, and wherein the TAC is applied to the first TAG based at least in part on the SSB and the first TAG being associated with the same CORESET pool index.

10. The UE of claim 1, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on the SSB associated with the first RACH message, wherein the first TAG is associated with the SSB, and wherein the TAC is applied to the first TAG based at least in part on the first TAG being associated with the SSB.

11. The UE of claim 1, wherein the first TAG is associated with communications with a first network node, and wherein the second TAG is associated with communications with a second network node.

12. The UE of claim 1, wherein the one or more processors are further configured to identify a beam failure with respect to the at least one set of BFD-RSs that triggered the transmission of the first RACH message.

13. A method of wireless communication performed by a user equipment (UE), the method comprising: receiving an indication of a first timing advance group (TAG) associated with a first wireless link of a serving cell and a second TAG associated with a second wireless link of the serving cell; transmitting, on the serving cell, a first random access channel (RACH) message based at least in part on a failure of a beam failure recovery (BFR) procedure associated with a beam failure associated with at least one set of BFD-RSs from a first set of beam failure detection (BFD) reference signals (RSs) associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link; receiving, based at least in part on transmitting the first RACH message, a second RACH message indicating a timing advance command (TAC) for the serving cell; and communicating with the serving cell based at least in part on an application of the TAC to the first TAG or the second TAG, the application of the TAC to the first TAG or the second TAG based at least in part on one or more of: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to the transmission of the first RACH message, a set of BFD-RSs of the first set of BFD-RSs or the second set of BFD-RSs for which the BFR procedure was not triggered, or a synchronization signal block (SSB) associated with the first RACH message.

14. The method of claim 13, wherein the first TAG is associated with a set of new beam identification RSs (NBI-RSs) or the first set of BFD-RSs based at least in part on one or more of: at least one of the set of NBI-RSs or the first set of BFD-RSs and the first TAG being associated with a same control resource set (CORESET) pool index value, a mapping rule, or the first TAG being configured for the set of NBI-RSs or the first set of BFD-RSs.

15. The method of claim 14, wherein the first TAG is configured for the set of NBI-RSs or configured in the first set of BFD-RSs based at least in part on a configuration of a TAG identity of the first TAG to: the set of NBI-RSs or the first set of BFD-RSs, or each RS in the set of NBI-RSs or the first set of BFD-RSs.

16. The method of claim 13, further comprising failing to identify the new candidate beam for any set of new beam identification RSs (NBI-RSs) prior to the transmission of the first RACH message, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beam is identified prior to the transmission of the first RACH message, and wherein the application of the TAC to the first TAG is based at least in part on the first TAG being a default TAG.

17. The method of claim 16, wherein the first TAG is a default TAG based at least in part on the first TAG being associated with: a first TAG index, a lowest TAG identity relative to a second TAG identity associated with the second TAG, or a default control resource set (CORESET) pool index.

18. The method of claim 13, further comprising identifying the new candidate beam for a set of new beam identification RSs (NBI-RSs) prior to the transmission of the first RACH message, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beam is identified prior to the transmission of the first RACH message, and wherein the TAC is applied to the first TAG based at least in part on the first TAG being associated with the set of NBI-RSs.

19. The method of claim 13, further comprising: identifying a first set of new candidate beams for a first set of new beam identification RSs (NBI-RSs) and a second set of new candidate beams for a second set of NBI-RSs prior to the transmission of the first RACH message; and selecting a synchronization signal block (SSB) associated with the first set of new candidate beams or the second set of new candidate beams, ​ wherein the application of the TAC to the first TAG or the second TAG is based at least in part on whether the new candidate beam was identified prior to transmission of the first RACH message, and wherein the TAC is applied to the first TAG based at least in part on the selected SSB being within the first set of candidate beams and the first TAG being associated with the first set of NBI-RSs.

20. The method of claim 13, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on a BFD-RS set, of the first BFD-RS set or the second BFD-RS set, that is not the at least one BFD-RS set for which the BFR procedure is not triggered, wherein the at least one BFD-RS set is associated with the first TAG and the BFD-RS set that is not the at least one BFD-RS set is associated with the second TAG, and wherein the TAC is applied to the second TAG based at least in part on the BFD-RS set being associated with the second TAG.

21. The method of claim 13, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on the SSB associated with the first RACH message, wherein the SSB and the first TAG are associated with a same control resource set (CORESET) pool index, and wherein the TAC is applied to the first TAG based at least in part on the SSB and the first TAG being associated with the same CORESET pool index.

22. The method of claim 13, wherein the application of the TAC to the first TAG or the second TAG is based at least in part on the SSB associated with the first RACH message, wherein the first TAG is associated with the SSB, and wherein the TAC is applied to the first TAG based at least in part on the first TAG being associated with the SSB.

23. The method of claim 13, wherein the first TAG is associated with communications with a first network node, and wherein the second TAG is associated with communications with a second network node.

24. The method of claim 13, further comprising identifying a beam failure for the at least one BFD-RS set that triggered the transmission of the first RACH message.

25. A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising: one or more instructions that, when executed by one or more processors of a user equipment (UE), cause the UE to: receive an indication of a first timing advance group (TAG) associated with a first wireless link of a serving cell and a second TAG associated with a second wireless link of the serving cell; transmit a first random access channel (RACH) message on the serving cell based at least in part on a failure of a beam failure recovery (BFR) procedure associated with at least one of a first set of beam failure detection (BFD) reference signals (RSs) associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link; receive a second RACH message indicating a timing advance command (TAC) for the serving cell based at least in part on transmitting the first RACH message; and communicate with the serving cell based at least in part on an application of the TAC to the first TAG or the second TAG, the application of the TAC to the first TAG or the second TAG based at least in part on one or more of: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to the transmission of the first RACH message, a set of BFD-RSs of the first set of BFD-RSs or the second set of BFD-RSs that is not the at least one set of BFD-RSs for which the BFR procedure was triggered, or a synchronization signal block (SSB) associated with the first RACH message.

26. The non-transitory computer-readable medium of claim 25, wherein the first TAG is associated with a set of new beam identification RSs (NBI-RSs) or the first set of BFD-RSs based at least in part on one or more of: at least one of the set of NBI-RSs or the first set of BFD-RSs and the first TAG being associated with a same control resource set (CORESET) pool index value, a mapping rule, or the first TAG being configured for the set of NBI-RSs or the first set of BFD-RSs.

27. The non-transitory computer-readable medium of claim 26, wherein the first TAG is configured for the set of NBI-RSs or in the first set of BFD-RSs based at least in part on a configuration of a TAG identification of the first TAG to: the set of NBI-RSs or the first set of BFD-RSs, or each RS of the set of NBI-RSs or the first set of BFD-RSs.

28. An apparatus for wireless communication, the apparatus comprising: means for receiving an indication of a first timing advance group (TAG) associated with a first wireless link of a serving cell and a second TAG associated with a second wireless link of the serving cell; means for transmitting a first random access channel (RACH) message on the serving cell based at least in part on a failure of a beam failure recovery (BFR) procedure associated with at least one of a first set of beam failure detection (BFD) reference signals (RSs) associated with the first wireless link or a second set of BFD-RSs associated with the second wireless link; a component for receiving a second RACH message indicating a timing advance command (TAC) for the serving cell based at least in part on the transmission of the first RACH message; and a component for communicating with the serving cell based at least in part on an application of the TAC to the first TAG or the second TAG, the application of the TAC to the first TAG or the second TAG based at least in part on one or more of: whether a new candidate beam associated with the first wireless link or the second wireless link was identified prior to the transmission of the first RACH message, a set of BFD-RSs in the first set of BFD-RSs or the second set of BFD-RSs for which the BFR procedure is not triggered, or a synchronization signal block (SSB) associated with the first RACH message.

29. The apparatus of claim 28, wherein the first TAG is associated with a set of new beam identification RSs (NBI-RSs) or the first set of BFD-RSs based at least in part on one or more of: at least one of the set of NBI-RSs or the first set of BFD-RSs and the first TAG being associated with a same control resource set (CORESET) pool index value, a mapping rule, or the first TAG being configured for the set of NBI-RSs or the first set of BFD-RSs.

30. The apparatus of claim 29, wherein the first TAG is configured for the set of NBI-RSs or in the first set of BFD-RSs based at least in part on a configuration of a TAG identification of the first TAG to: the set of NBI-RSs or the first set of BFD-RSs, or each RS in the set of NBI-RSs or the first set of BFD-RSs.

Images