Patent Publication Number: US-2023133908-A1

Title: Carrier aggregation for mixed frequency ranges

Description:
INTRODUCTION 
     Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for carrier aggregation. 
     Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, or the like). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE). LTE/LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP). 
     A wireless network may include one or more base stations that support communication for a user equipment (UE) or multiple UEs. A UE may communicate with a base station via downlink communications and uplink communications. “Downlink” (or “DL”) refers to a communication link from the base station to the UE, and “uplink” (or “UL”) refers to a communication link from the UE to the base station. 
     The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different UEs to communicate on a municipal, national, regional, and/or global level. New Radio (NR), which may be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the 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, using CP-OFDM and/or single-carrier frequency division multiplexing (SC-FDM) (also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink, as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. As the demand for mobile broadband access continues to increase, further improvements in LTE, NR, and other radio access technologies remain useful. 
     SUMMARY 
     Some aspects described herein relate to a method of wireless communication performed by a user equipment (UE). The method may include communicating on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters. The method may include detecting a radio link control (RLC) discontinuity on at least one set of carriers, of the first set of carriers or the second set of carriers. The method may include transmitting an RLC status report in accordance with an RLC timer that is based at least in part on at least one of a first hybrid automatic repeat request (HARQ) parameter associated with the first set of parameters or a second HARQ parameter associated with the second set of parameters, wherein the RLC timer based at least in part on a number of RLC duplicates received by the UE. 
     Some aspects described herein relate to a method of wireless communication performed by a user equipment (UE). The method may include transmitting a communication on one of a first set of carriers in a first frequency range (FR) or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology. The method may include receiving a radio link control (RLC) status report indicating an RLC discontinuity associated with the communication. The method may include one of, performing a retransmission of the communication on a preferred carrier associated with the preferred numerology in response to an uplink grant on the preferred carrier being received within a length of time, or performing the retransmission of the communication on a first available uplink grant when no uplink grant on the preferred carrier is received within the length of time. 
     Some aspects described herein relate to a method of wireless communication performed by a user equipment (UE). The method may include transmitting an indication to avoid Voice over New Radio (VoNR) communication in a first frequency range. The method may include generating a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet. The method may include transmitting the first TB in the first frequency range. The method may include transmitting a second TB associated with the VoNR communication in a second frequency range based at least in part on the first TB including the non-zero padding buffer status report or the voice packet. 
     Some aspects described herein relate to a user equipment (UE) for wireless communication. The user equipment may include a memory and one or more processors coupled to the memory. The one or more processors may be configured to communicate on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters. The one or more processors may be configured to detect a radio link control (RLC) discontinuity on at least one set of carriers, of the first set of carriers or the second set of carriers. The one or more processors may be configured to transmit an RLC status report in accordance with an RLC timer that is based at least in part on at least one of a first hybrid automatic repeat request (HARQ) parameter associated with the first set of parameters or a second HARQ parameter associated with the second set of parameters, wherein the RLC timer based at least in part on a number of RLC duplicates received by the UE. 
     Some aspects described herein relate to a UE for wireless communication. The UE may include a memory and one or more processors coupled to the memory. The one or more processors may be configured to transmit a communication on one of a first set of carriers in a first frequency range (FR) or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology. The one or more processors may be configured to receive a radio link control (RLC) status report indicating an RLC discontinuity associated with the communication. The one or more processors may be configured to one of. 
     Some aspects described herein relate to a UE for wireless communication. The UE may include a memory and one or more processors coupled to the memory. The one or more processors may be configured to transmit an indication to avoid Voice over New Radio (VoNR) communication in a first frequency range. The one or more processors may be configured to generate a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet. The one or more processors may be configured to transmit the first TB in the first frequency range. The one or more processors may be configured to transmit a second TB associated with the VoNR communication in a second frequency range based at least in part on the first TB including the non-zero padding buffer status report or the voice packet. 
     Some aspects described herein relate to a non-transitory computer-readable medium that stores a set of instructions for wireless communication by a user equipment (UE). The set of instructions, when executed by one or more processors of the UE, may cause the UE to communicate on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters. The set of instructions, when executed by one or more processors of the UE, may cause the UE to detect a radio link control (RLC) discontinuity on at least one set of carriers, of the first set of carriers or the second set of carriers. The set of instructions, when executed by one or more processors of the UE, may cause the UE to transmit an RLC status report in accordance with an RLC timer that is based at least in part on at least one of a first hybrid automatic repeat request (HARQ) parameter associated with the first set of parameters or a second HARQ parameter associated with the second set of parameters, wherein the RLC timer based at least in part on a number of RLC duplicates received by the UE. 
     Some aspects described herein relate to a non-transitory computer-readable medium that stores a set of instructions for wireless communication by a one or more instructions that, when executed by one or more processors of an UE. The set of instructions, when executed by one or more processors of the one or more instructions that, when executed by one or more processors of an UE, may cause the one or more instructions that, when executed by one or more processors of an UE to transmit a communication on one of a first set of carriers in a first frequency range (FR) or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology. The set of instructions, when executed by one or more processors of the one or more instructions that, when executed by one or more processors of an UE, may cause the one or more instructions that, when executed by one or more processors of an UE to receive a radio link control (RLC) status report indicating an RLC discontinuity associated with the communication. The set of instructions, when executed by one or more processors of the one or more instructions that, when executed by one or more processors of an UE, may cause the one or more instructions that, when executed by one or more processors of an UE to one of. 
     Some aspects described herein relate to a non-transitory computer-readable medium that stores a set of instructions for wireless communication by a one or more instructions that, when executed by one or more processors of an UE. The set of instructions, when executed by one or more processors of the one or more instructions that, when executed by one or more processors of an UE, may cause the one or more instructions that, when executed by one or more processors of an UE to transmit an indication to avoid Voice over New Radio (VoNR) communication in a first frequency range. The set of instructions, when executed by one or more processors of the one or more instructions that, when executed by one or more processors of an UE, may cause the one or more instructions that, when executed by one or more processors of an UE to generate a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet. The set of instructions, when executed by one or more processors of the one or more instructions that, when executed by one or more processors of an UE, may cause the one or more instructions that, when executed by one or more processors of an UE to transmit the first TB in the first frequency range. The set of instructions, when executed by one or more processors of the one or more instructions that, when executed by one or more processors of an UE, may cause the one or more instructions that, when executed by one or more processors of an UE to transmit a second TB associated with the VoNR communication in a second frequency range based at least in part on the first TB including the non-zero padding buffer status report or the voice packet. 
     Some aspects described herein relate to an apparatus for wireless communication. The apparatus may include means for communicating on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters. The apparatus may include means for detecting a radio link control (RLC) discontinuity on at least one set of carriers, of the first set of carriers or the second set of carriers. The apparatus may include means for transmitting an RLC status report in accordance with an RLC timer that is based at least in part on at least one of a first hybrid automatic repeat request (HARQ) parameter associated with the first set of parameters or a second HARQ parameter associated with the second set of parameters, wherein the RLC timer based at least in part on a number of RLC duplicates received by the UE. 
     Some aspects described herein relate to an apparatus for wireless communication. The apparatus may include means for transmitting a communication on one of a first set of carriers in a first frequency range (FR) or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology. The apparatus may include means for receiving a radio link control (RLC) status report indicating an RLC discontinuity associated with the communication. The apparatus may include one of, means for performing a retransmission of the communication on a preferred carrier associated with the preferred numerology in response to an uplink grant on the preferred carrier being received within a length of time, or means for performing the retransmission of the communication on a first available uplink grant when no uplink grant on the preferred carrier is received within the length of time. 
     Some aspects described herein relate to an apparatus for wireless communication. The apparatus may include means for transmitting an indication to avoid Voice over New Radio (VoNR) communication in a first frequency range. The apparatus may include means for generating a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet. The apparatus may include means for transmitting the first TB in the first frequency range. The apparatus may include means for transmitting a second TB associated with the VoNR communication in a second frequency range based at least in part on the first TB including the non-zero padding buffer status report or the voice packet. 
     Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and/or processing system as substantially described with reference to and as illustrated by the drawings and specification. 
     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 may be better understood. Additional features and advantages will be described hereinafter. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. Characteristics of the concepts disclosed herein, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purpose of illustration and description, and not as a definition of the limits of the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects. The same reference numbers in different drawings may identify the same or similar elements. 
         FIG.  1    is a diagram illustrating an example of a wireless network, in accordance with the present disclosure. 
         FIG.  2    is a diagram illustrating an example of a base station in communication with a user equipment (UE) in a wireless network, in accordance with the present disclosure. 
         FIGS.  3 A and  3 B  are diagrams illustrating examples of a user plane protocol stack and a control plane protocol stack for a base station and a core network in communication with a UE, in accordance with the present disclosure. 
         FIGS.  4 A- 4 C  are diagrams illustrating examples of carrier aggregation, in accordance with the present disclosure. 
         FIG.  5    is a diagram illustrating an example of radio link control (RLC) holes in two numerologies and a reassembly timer associated with the RLC holes, in accordance with the present disclosure. 
         FIG.  6    is a diagram illustrating an example of signaling associated with RLC operation for carrier aggregation with mixed numerologies, in accordance with the present disclosure. 
         FIGS.  7 A- 7 C  are diagrams illustrating examples of identifying a numerology associated with an RLC hole based at least in part on correlating timing of cyclic redundancy check errors with RLC holes, in accordance with the present disclosure. 
         FIG.  8    is a diagram illustrating an example of identifying a numerology associated with an RLC hole based at least in part on correlating a transport block size with an RLC hole, in accordance with the present disclosure. 
         FIG.  9    is a diagram illustrating an example of ambiguity associated with an RLC hole. 
         FIG.  10    is a diagram illustrating an example of identifying a numerology associated with an RLC hole based at least in part on correlating a transport block size with an RLC hole with a timing mismatch, in accordance with the present disclosure. 
         FIG.  11    is a diagram illustrating an example of independent RLC status reporting regarding a first numerology and a second numerology using reassembly timers running in parallel, in accordance with the present disclosure. 
         FIG.  12    is a diagram illustrating an example of RLC hole detection for a leading carrier and a lagging carrier. 
         FIG.  13    is a diagram illustrating an example of RLC timer modification based at least in part on a HARQ latency, in accordance with the present disclosure. 
         FIG.  14    is a diagram illustrating an example of training and using a machine learning model in connection with determining whether or how to modify an RLC timer length, in accordance with the present disclosure. 
         FIG.  15    is a diagram illustrating an example of RLC status reporting based at least in part on a HARQ latency associated with a carrier, in accordance with the present disclosure. 
         FIG.  16    is a diagram illustrating an example of transmitting a transport block with a poll bit on two or more numerologies, in accordance with the present disclosure. 
         FIG.  17    is a diagram illustrating an example of signaling associated with transport block generation based at least in part on a Voice over NR (VoNR) call in FR2, in accordance with the present disclosure. 
         FIG.  18    is a diagram illustrating an example of an O-RAN architecture, in accordance with the present disclosure. 
         FIG.  19    is a diagram illustrating an example process performed by a UE, in accordance with the present disclosure. 
         FIG.  20    is a diagram illustrating an example process performed by a UE, in accordance with the present disclosure. 
         FIG.  21    is a diagram illustrating an example process performed by a UE, in accordance with the present disclosure. 
         FIG.  22    is a diagram of an example apparatus for wireless communication, in accordance with the present disclosure. 
         FIG.  23    is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system, in accordance with the present disclosure. 
         FIG.  24    is a diagram illustrating an example implementation of code and circuitry for an apparatus, in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     A UE may have a capability to communicate in multiple frequency ranges (FRs), such as the sub-6 GHz FR (referred to as FR1) and the mmWave FR (referred to as FR2). The UE may use different numerologies when communicating in different frequency ranges. A numerology is a set of parameters that indicates a subcarrier spacing and a cyclic prefix length of a carrier. A subcarrier spacing indicates how wide subcarriers are on the carrier, and can be used to derive the length of a slot on the carrier. Different numerologies may be associated with different bandwidths and different slot lengths. As the numerology increases (leading to a wider bandwidth), the length of a slot decreases proportionately. 
     Some UEs may have a capability to perform carrier aggregation of carriers in different FRs (e.g., with different numerologies). “Carrier aggregation” refers to communicating using multiple frequency regions (referred to as carriers). For example, a UE may have a capability to simultaneously communicate on a first set of carriers in FR1 and a second set of carriers in FR2, where the first set of carriers and the second set of carriers are associated with different numerologies. 
     The radio link control (RLC) layer of a UE performs reassembly of segmented RLC protocol data units (PDUs), among numerous other functions. “Reassembly” refers to assembling RLC PDUs into an RLC service data unit (SDU) for a higher layer of a protocol stack of the UE, such as a packet data convergence protocol (PDCP) layer. If reassembly cannot be accomplished due to one or more missing transport blocks (TBs), the RLC layer may identify an RLC hole in a given slot. As used herein, an RLC hole refers to a set of missing RLC sequence numbers associated with one or more RLC PDUs. For example, the UE may identify an RLC hole at RLC sequence number X when RLC sequence number X−1 and RLC sequence number X+1 have been received and RLC sequence number X has not been received. The UE may buffer communications received after the RLC hole is identified until the RLC hole can be resolved. If the RLC hole persists until a reassembly timer has elapsed, or if the UE receives a poll PDU (that is, a message requesting an RLC status report), the UE may transmit an RLC status report that indicates the RLC hole. The operation of the RLC layer may be based at least in part on RLC parameters that may define a set of RLC timers, such as the reassembly timer and various parameters relating to poll PDU transmission. 
     Different numerologies may be associated with different RLC parameters or RLC timers, since different numerologies have different bandwidths and subcarrier spacings. However, the UE may be associated with a single RLC entity (e.g., RLC layer), so that RLC operations of the UE across all carriers are performed by the single RLC entity. This may be problematic in the case of carrier aggregation across multiple numerologies. As one example, if the UE experiences an RLC hole associated with a first numerology and an RLC hole associated with a second numerology in quick succession, the UE may have to run successive reassembly timers for the first numerology, then the second numerology. Thus, the UE may have to buffer communications for the combined length of the successive reassembly timers, which requires significant memory resources. As another example, if the UE cannot differentiate which numerology is associated with an RLC hole, the UE may have to use a more conservative set of RLC parameters or timers (e.g., a longer reassembly timer) for the RLC hole, which may be inefficient and may degrade throughput. 
     Some techniques and apparatuses described herein provide identification (or estimation) of whether an RLC hole is associated with a first numerology or a second numerology. Based at least in part on the numerology associated with the RLC hole, the UE can selectively apply different sets of RLC parameters (e.g., different reassembly timers or the like) for different RLC holes. For example, the UE may use a shorter reassembly timer for an RLC hole associated with FR2, and may use a longer reassembly timer for an RLC hole associated with FR1, thereby improving resource utilization relative to using a more conservative set of RLC parameters. Furthermore, in some techniques and apparatuses described herein, the UE may have a capability to run reassembly timers in parallel for different RLC holes associated with different numerologies, and may have a capability to report RLC holes for specific numerologies, which reduces packet delay as well as UE buffer usage. 
     Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This 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 disclosure to those skilled in the art. One skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the 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 disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim. 
     Several aspects of telecommunication systems will now be presented with reference to various apparatuses and techniques. These apparatuses and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, or the like (collectively referred to as “elements”). These elements may be implemented using hardware, software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. 
     While aspects may be described herein using terminology commonly associated with a 5G or New Radio (NR) radio access technology (RAT), aspects of the present disclosure can be applied to other RATs, such as a 3G RAT, a 4G RAT, and/or a RAT subsequent to 5G (e.g., 6G). 
       FIG.  1    is a diagram illustrating an example of a wireless network  100 , in accordance with the present disclosure. The wireless network  100  may be or may include elements of a 5G (e.g., NR) network and/or a 4G (e.g., Long Term Evolution (LTE)) network, among other examples. The wireless network  100  may include one or more base stations  110  (shown as a BS  110   a , a BS  110   b , a BS  110   c , and a BS  110   d ), a user equipment (UE)  120  or multiple UEs  120  (shown as a UE  120   a , a UE  120   b , a UE  120   c , a UE  120   d , and a UE  120   e ), and/or other network entities. A base station  110  is an entity that communicates with UEs  120 . A base station  110  (sometimes referred to as a BS) may include, for example, an NR base station, an LTE base station, a Node B, an eNB (e.g., in 4G), a gNB (e.g., in 5G), an access point, and/or a transmission reception point (TRP). Each base station  110  may provide communication coverage for a particular geographic area. In the Third Generation Partnership Project (3GPP), the term “cell” can refer to a coverage area of a base station  110  and/or a base station subsystem serving this coverage area, depending on the context in which the term is used. 
     A base station  110  may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs  120  with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs  120  with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs  120  having association with the femto cell (e.g., UEs  120  in a closed subscriber group (CSG)). A base station  110  for a macro cell may be referred to as a macro base station. A base station  110  for a pico cell may be referred to as a pico base station. A base station  110  for a femto cell may be referred to as a femto base station or an in-home base station. In the example shown in  FIG.  1   , the BS  110   a  may be a macro base station for a macro cell  102   a , the BS  110   b  may be a pico base station for a pico cell  102   b , and the BS  110   c  may be a femto base station for a femto cell  102   c . A base station may support one or multiple (e.g., three) cells. 
     In some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a base station  110  that is mobile (e.g., a mobile base station). In some examples, the base stations  110  may be interconnected to one another and/or to one or more other base stations  110  or network nodes (not shown) in the wireless network  100  through various types of backhaul interfaces, such as a direct physical connection or a virtual network, using any suitable transport network. 
     The wireless network  100  may 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 base station  110  or a UE  120 ) and send a transmission of the data to a downstream station (e.g., a UE  120  or a base station  110 ). A relay station may be a UE  120  that can relay transmissions for other UEs  120 . In the example shown in  FIG.  1   , the BS  110   d  (e.g., a relay base station) may communicate with the BS  110   a  (e.g., a macro base station) and the UE  120   d  in order to facilitate communication between the BS  110   a  and the UE  120   d . A base station  110  that relays communications may be referred to as a relay station, a relay base station, a relay, or the like. 
     The wireless network  100  may be a heterogeneous network that includes base stations  110  of different types, such as macro base stations, pico base stations, femto base stations, relay base stations, or the like. These different types of base stations  110  may have different transmit power levels, different coverage areas, and/or different impacts on interference in the wireless network  100 . For example, macro base stations may have a high transmit power level (e.g., 5 to 40 watts) whereas pico base stations, femto base stations, and relay base stations may have lower transmit power levels (e.g., 0.1 to 2 watts). 
     A network controller  130  may couple to or communicate with a set of base stations  110  and may provide coordination and control for these base stations  110 . The network controller  130  may communicate with the base stations  110  via a backhaul communication link. The base stations  110  may communicate with one another directly or indirectly via a wireless or wireline backhaul communication link. 
     The UEs  120  may be dispersed throughout the wireless network  100 , and each UE  120  may be stationary or mobile. A UE  120  may include, for example, an access terminal, a terminal, a mobile station, and/or a subscriber unit. A UE  120  may be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device, 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, and/or a satellite radio), a vehicular component or sensor, a smart meter/sensor, industrial manufacturing equipment, a global positioning system device, and/or any other suitable device that is configured to communicate via a wireless or wired medium. 
     Some UEs  120  may be considered machine-type communication (MTC) or evolved or enhanced machine-type communication (eMTC) UEs. An MTC UE and/or an eMTC UE may include, for example, a robot, a drone, a remote device, a sensor, a meter, a monitor, and/or a location tag, that may communicate with a base station, another device (e.g., a remote device), or some other entity. Some UEs  120  may be considered Internet-of-Things (IoT) devices, and/or may be implemented as NB-IoT (narrowband IoT) devices. Some UEs  120  may be considered a Customer Premises Equipment. A UE  120  may be included inside a housing that houses components of the UE  120 , such as processor components and/or memory components. In some examples, the processor components and the memory components may be coupled together. For example, the processor components (e.g., one or more processors) and the memory components (e.g., a memory) may be operatively coupled, communicatively coupled, electronically coupled, and/or electrically coupled. 
     In general, any number of wireless networks  100  may be deployed in a given geographic area. Each wireless network  100  may support a particular RAT and may operate on one or more frequencies. A RAT may be referred to as a radio technology, an air interface, or the like. A frequency may be referred to as a carrier, a frequency channel, or the like. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed. 
     In some examples, two or more UEs  120  (e.g., shown as UE  120   a  and UE  120   e ) may communicate directly using one or more sidelink channels (e.g., without using a base station  110  as an intermediary to communicate with one another). For example, the UEs  120  may communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, a vehicle-to-everything (V2X) protocol (e.g., which may include a vehicle-to-vehicle (V2V) protocol, a vehicle-to-infrastructure (V2I) protocol, or a vehicle-to-pedestrian (V2P) protocol), and/or a mesh network. In such examples, a UE  120  may perform scheduling operations, resource selection operations, and/or other operations described elsewhere herein as being performed by the base station  110 . 
     The electromagnetic spectrum is often subdivided, by frequency/wavelength, into various classes, bands, channels, etc. 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). It should be understood that 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 with regard to FR2, which is often referred to (interchangeably) as a “millimeter wave” band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHz-300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band. 
     The frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Recent 5G NR studies have identified an operating band for these mid-band frequencies as frequency range designation FR3 (7.125 GHz-24.25 GHz). Frequency bands falling within FR3 may inherit FR1 characteristics and/or FR2 characteristics, and thus may effectively extend features of FR1 and/or FR2 into mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operation beyond 52.6 GHz. For example, three higher operating bands have been identified as frequency range designations FR4a 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 frequency bands falls within the EHF band. 
     With the above examples in mind, unless specifically stated otherwise, it should be understood that the term “sub-6 GHz” or the like, if used herein, may broadly represent frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. Further, unless specifically stated otherwise, it should be understood that the term “millimeter wave” or the like, if used herein, may broadly represent frequencies that may include mid-band frequencies, may be within FR2, FR4, FR4-a or FR4-1, and/or FR5, or may 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, and/or FR5) may be modified, and techniques described herein are applicable to those modified frequency ranges. 
     In some aspects, the UE  120  may include a communication manager  140 . As described in more detail elsewhere herein, the communication manager  140  may communicate on a first set of carriers in a first frequency range (FR) and a second set of carriers in a second FR; detect a radio link control (RLC) discontinuity on at least one of the first set of carriers or the second set of carriers; identify one or more FRs, of the first FR and the second FR, in which the RLC discontinuity occurred; and transmit an RLC status report based at least in part on the identified one or more FRs. Additionally, or alternatively, the communication manager  140  may perform one or more other operations described herein. 
     In some aspects, the UE  120  may include a communication manager  140 . As described in more detail elsewhere herein, the communication manager  140  may transmit a communication on one of a first set of carriers in a first FR or a second set of carriers in a second FR, wherein the communication is associated with a numerology; receive a RLC status report indicating an RLC discontinuity associated with the communication; and perform a retransmission of the communication, wherein the retransmission is on a carrier associated with the numerology if an uplink grant on the carrier is received within a length of time, and wherein the retransmission is on a first available uplink grant otherwise. Additionally, or alternatively, the communication manager  140  may perform one or more other operations described herein. 
     In some aspects, the UE  120  may include a communication manager  140 . As described in more detail elsewhere herein, the communication manager  140  may transmit an indication to avoid Voice over New Radio (VoNR) communication in a first frequency range; generate a transport block (TB) for transmission in the first frequency range, wherein the TB includes padding such that a TB associated with the VoNR communication is transmitted in a second frequency range; and transmit the TB in the first frequency range. Additionally, or alternatively, the communication manager  140  may perform one or more other operations described herein. 
     As indicated above,  FIG.  1    is provided as an example. Other examples may differ from what is described with regard to  FIG.  1   . 
       FIG.  2    is a diagram illustrating an example  200  of a base station  110  in communication with a UE  120  in a wireless network  100 , in accordance with the present disclosure. The base station  110  may be equipped with a set of antennas  234   a  through  234   t , such as T antennas (T≥1). The UE  120  may be equipped with a set of antennas  252   a  through  252   r , such as R antennas (R≥1). 
     At the base station  110 , a transmit processor  220  may receive data, from a data source  212 , intended for the UE  120  (or a set of UEs  120 ). The transmit processor  220  may 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 that UE  120 . The base station  110  may process (e.g., encode and modulate) the data for the UE  120  based at least in part on the MCS(s) selected for the UE  120  and may provide data symbols for the UE  120 . The transmit processor  220  may process system information (e.g., for semi-static resource partitioning information (SRPI)) and control information (e.g., CQI requests, grants, and/or upper layer signaling) and provide overhead symbols and control symbols. The transmit processor  220  may 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  may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and/or the reference symbols, if applicable, and may provide a set of output symbol streams (e.g., T output symbol streams) to a corresponding set of modems  232  (e.g., T modems), shown as modems  232   a  through  232   t . For example, each output symbol stream may be provided to a modulator component (shown as MOD) of a modem  232 . Each modem  232  may 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  may further use a respective modulator component to process (e.g., convert to analog, amplify, filter, and/or upconvert) the output sample stream to obtain a downlink signal. The modems  232   a  through  232   t  may transmit a set of downlink signals (e.g., T downlink signals) via a corresponding set of antennas  234  (e.g., T antennas), shown as antennas  234   a  through  234   t.    
     At the UE  120 , a set of antennas  252  (shown as antennas  252   a  through  252   r ) may receive the downlink signals from the base station  110  and/or other base stations  110  and may provide a set of received signals (e.g., R received signals) to a set of modems  254  (e.g., R modems), shown as modems  254   a  through  254   r . For example, each received signal may be provided to a demodulator component (shown as DEMOD) of a modem  254 . Each modem  254  may use a respective demodulator component to condition (e.g., filter, amplify, downconvert, and/or digitize) a received signal to obtain input samples. Each modem  254  may use a demodulator component to further process the input samples (e.g., for OFDM) to obtain received symbols. A MIMO detector  256  may obtain received symbols from the modems  254 , may perform MIMO detection on the received symbols if applicable, and may provide detected symbols. A receive processor  258  may process (e.g., demodulate and decode) the detected symbols, may provide decoded data for the UE  120  to a data sink  260 , and may provide decoded control information and system information to a controller/processor  280 . The term “controller/processor” may refer to one or more controllers, one or more processors, or a combination thereof. A channel processor may determine a reference signal received power (RSRP) parameter, a received signal strength indicator (RSSI) parameter, a reference signal received quality (RSRQ) parameter, and/or a CQI parameter, among other examples. In some examples, one or more components of the UE  120  may be included in a housing  284 . 
     The network controller  130  may include a communication unit  294 , a controller/processor  290 , and a memory  292 . The network controller  130  may include, for example, one or more devices in a core network. The network controller  130  may communicate with the base station  110  via the communication unit  294 . 
     One or more antennas (e.g., antennas  234   a  through  234   t  and/or antennas  252   a  through  252   r ) may include, or may be included within, one or more antenna panels, one or more antenna groups, one or more sets of antenna elements, and/or one or more antenna arrays, among other examples. An antenna panel, an antenna group, a set of antenna elements, and/or an antenna array may include one or more antenna elements (within a single housing or multiple housings), a set of coplanar antenna elements, a set of non-coplanar antenna elements, and/or one or more antenna elements coupled to one or more transmission and/or reception components, such as one or more components of  FIG.  2   . 
     On the uplink, at the UE  120 , a transmit processor  264  may receive and process data from a data source  262  and control information (e.g., for reports that include RSRP, RSSI, RSRQ, and/or CQI) from the controller/processor  280 . The transmit processor  264  may generate reference symbols for one or more reference signals. The symbols from the transmit processor  264  may be precoded by a TX MIMO processor  266  if applicable, further processed by the modems  254  (e.g., for DFT-s-OFDM or CP-OFDM), and transmitted to the base station  110 . In some examples, the modem  254  of the UE  120  may include a modulator and a demodulator. In some examples, the UE  120  includes a transceiver. The transceiver may include any combination of the antenna(s)  252 , the modem(s)  254 , the MIMO detector  256 , the receive processor  258 , the transmit processor  264 , and/or the TX MIMO processor  266 . The transceiver may be used by a processor (e.g., the controller/processor  280 ) and the memory  282  to perform aspects of any of the methods described herein. 
     At the base station  110 , the uplink signals from UE  120  and/or other UEs may be received by the antennas  234 , processed by the modem  232  (e.g., a demodulator component, shown as DEMOD, of the modem  232 ), detected by a MIMO detector  236  if applicable, and further processed by a receive processor  238  to obtain decoded data and control information sent by the UE  120 . The receive processor  238  may provide the decoded data to a data sink  239  and provide the decoded control information to the controller/processor  240 . The base station  110  may include a communication unit  244  and may communicate with the network controller  130  via the communication unit  244 . The base station  110  may include a scheduler  246  to schedule one or more UEs  120  for downlink and/or uplink communications. In some examples, the modem  232  of the base station  110  may include a modulator and a demodulator. In some examples, the base station  110  includes a transceiver. The transceiver may include any combination of the antenna(s)  234 , the modem(s)  232 , the MIMO detector  236 , the receive processor  238 , the transmit processor  220 , and/or the TX MIMO processor  230 . The transceiver may be used by a processor (e.g., the controller/processor  240 ) and the memory  242  to perform aspects of any of the methods described herein. 
     The controller/processor  240  of the base station  110 , the controller/processor  280  of the UE  120 , and/or any other component(s) of  FIG.  2    may perform one or more techniques associated with mixed numerology carrier aggregation, as described in more detail elsewhere herein. For example, the controller/processor  240  of the base station  110 , the controller/processor  280  of the UE  120 , and/or any other component(s) of  FIG.  2    may perform or direct operations of, for example, process  1900  of  FIG.  19   , process  2000  of  FIG.  20   , process  2100  of  FIG.  21   , and/or other processes as described herein. The memory  242  and the memory  282  may store data and program codes for the base station  110  and the UE  120 , respectively. In some examples, the memory  242  and/or the memory  282  may include a non-transitory computer-readable medium storing one or more instructions (e.g., code and/or program code) for wireless communication. For example, the one or more instructions, when executed (e.g., directly, or after compiling, converting, and/or interpreting) by one or more processors of the base station  110  and/or the UE  120 , may cause the one or more processors, the UE  120 , and/or the base station  110  to perform or direct operations of, for example, process  1900  of  FIG.  19   , process  2000  of  FIG.  20   , process  2100  of  FIG.  21   , and/or other processes as described herein. In some examples, executing instructions may include running the instructions, converting the instructions, compiling the instructions, and/or interpreting the instructions, among other examples. 
     While blocks in  FIG.  2    are illustrated as distinct components, the functions described above with respect to the blocks may be implemented in a single hardware, software, or combination component or in various combinations of components. For example, the functions described with respect to the transmit processor  264 , the receive processor  258 , and/or the TX MIMO processor  266  may be performed by or under the control of the controller/processor  280 . 
     As indicated above,  FIG.  2    is provided as an example. Other examples may differ from what is described with regard to  FIG.  2   . 
       FIGS.  3 A and  3 B  are diagrams illustrating an example  300  of a user plane protocol stack (in  FIG.  3 A ) and a control plane protocol stack (in  FIG.  3 B ) for a base station  110  and a core network in communication with a UE  120 , in accordance with the present disclosure. 
     On the user plane, the UE  120  and the BS  110  may include respective physical (PHY) layers, medium access control (MAC) layers, radio link control (RLC) layers, packet data convergence protocol (PDCP) layers, and service data adaptation protocol (SDAP) layers. A user plane function may handle transport of user data between the UE  120  and the BS  110 . On the control plane, the UE  120  and the BS  110  may include respective radio resource control (RRC) layers. Furthermore, the UE  120  may include a non-access stratum (NAS) layer in communication with an NAS layer of an access and management mobility function (AMF). The AMF may be associated with a core network associated with the BS  110 , such as a 5G core network (5GC) or a next-generation radio access network (NG-RAN). A control plane function may handle transport of control information between the UE and the core network. Generally, a first layer is referred to as higher than a second layer if the first layer is further from the PHY layer than the second layer. For example, the PHY layer may be referred to as a lowest layer, and the SDAP/PDCP/RLC/MAC layer may be referred to as higher than the PHY layer and lower than the RRC layer. An application (APP) layer, not shown in  FIG.  3   , may be higher than the SDAP/PDCP/RLC/MAC layer. In some cases, an entity may handle the services and functions of a given layer (e.g., a PDCP entity may handle the services and functions of the PDCP layer), though the description herein refers to the layers themselves as handling the services and functions. 
     The RRC layer may handle communications related to configuring and operating the UE  120 , such as: broadcast of system information related to the access stratum (AS) and the NAS; paging initiated by the 5GC or the NG-RAN; establishment, maintenance, and release of an RRC connection between the UE and the NG-RAN, including addition, modification, and release of carrier aggregation, as well as addition, modification, and release of dual connectivity; security functions including key management; establishment, configuration, maintenance, and release of signaling radio bearers (SRBs) and data radio bearers (DRBs); mobility functions (e.g., handover and context transfer, UE cell selection and reselection and control of cell selection and reselection, inter-RAT mobility); quality of service (QoS) management functions; UE measurement reporting and control of the reporting; detection of and recovery from radio link failure; and NAS message transfer between the NAS layer and the lower layers of the UE  120 . The RRC layer is frequently referred to as Layer 3 (L3). 
     The SDAP layer, PDCP layer, RLC layer, and MAC layer may be collectively referred to as Layer 2 (L2). Thus, in some cases, the SDAP, PDCP, RLC, and MAC layers are referred to as sublayers of Layer 2. On the transmitting side (e.g., if the UE  120  is transmitting an uplink communication or the BS  110  is transmitting a downlink communication), the SDAP layer may receive a data flow in the form of a QoS flow. A QoS flow is associated with a QoS identifier, which identifies a QoS parameter associated with the QoS flow, and a QoS flow identifier (QFI), which identifies the QoS flow. Policy and charging parameters are enforced at the QoS flow granularity. A QoS flow can include one or more service data flows (SDFs), so long as each SDF of a QoS flow is associated with the same policy and charging parameters. In some aspects, the RRC/NAS layer may generate control information to be transmitted and may map the control information to one or more radio bearers for provision to the PDCP layer. 
     The SDAP layer, or the RRC/NAS layer, may map QoS flows or control information to radio bearers. Thus, the SDAP layer may be said to handle QoS flows on the transmitting side. The SDAP layer may provide the QoS flows to the PDCP layer via the corresponding radio bearers. The PDCP layer may map radio bearers to RLC channels. The PDCP layer may handle various services and functions on the user plane, including sequence numbering, header compression and decompression (if robust header compression is enabled), transfer of user data, reordering and duplicate detection (if in-order delivery to layers above the PDCP layer is required), PDCP protocol data unit (PDU) routing (in case of split bearers), retransmission of PDCP service data units (SDUs), ciphering and deciphering, PDCP SDU discard (e.g., in accordance with a timer, as described elsewhere herein), PDCP re-establishment and data recovery for RLC acknowledged mode (AM), and duplication of PDCP PDUs. The PDCP layer may handle similar services and functions on the control plane, including sequence numbering, ciphering, deciphering, integrity protection, transfer of control plane data, duplicate detection, and duplication of PDCP PDUs. 
     The PDCP layer may provide data, in the form of PDCP PDUs, to the RLC layer via RLC channels. The RLC layer may handle transfer of upper layer PDUs to the MAC and/or PHY layers, sequence numbering independent of PDCP sequence numbering, error correction via automatic repeat requests (ARQ), segmentation and re-segmentation, reassembly of an SDU, RLC SDU discard, and RLC re-establishment. 
     The RLC layer may provide data, mapped to logical channels, to the MAC layer. The services and functions of the MAC layer include mapping between logical channels and transport channels (used by the PHY layer as described below), multiplexing/demultiplexing of MAC SDUs belonging to one or different logical channels into/from transport blocks (TBs) delivered to/from the physical layer on transport channels, scheduling information reporting, error correction through hybrid ARQ (HARQ), priority handling between UEs by means of dynamic scheduling, priority handling between logical channels of one UE by means of logical channel prioritization, and padding. 
     The MAC layer may package data from logical channels into TBs, and may provide the TBs on one or more transport channels to the PHY layer. The PHY layer may handle various operations relating to transmission of a data signal, as described in more detail in connection with  FIG.  2   . The PHY layer is frequently referred to as Layer 1 (L1). 
     On the receiving side (e.g., if the UE  120  is receiving a downlink communication or the BS  110  is receiving an uplink communication), the operations may be similar to those described for the transmitting side, but reversed. For example, the PHY layer may receive TBs and may provide the TBs on one or more transport channels to the MAC layer. The MAC layer may map the transport channels to logical channels and may provide data to the RLC layer via the logical channels. The RLC layer may map the logical channels to RLC channels and may provide data to the PDCP layer via the RLC channels. The PDCP layer may map the RLC channels to radio bearers and may provide data to the SDAP layer or the RRC/NAS layer via the radio bearers. 
     Data may be passed between the layers in the form of PDUs and SDUs. An SDU is a unit of data that has been passed from a layer or sublayer to a lower layer. For example, the PDCP layer may receive a PDCP SDU. A given layer may then encapsulate the unit of data into a PDU and may pass the PDU to a lower layer. For example, the PDCP layer may encapsulate the PDCP SDU into a PDCP PDU and may pass the PDCP PDU to the RLC layer. The RLC layer may receive the PDCP PDU as an RLC SDU, may encapsulate the RLC SDU into an RLC PDU, and so on. In effect, the PDU carries the SDU as a payload. 
     The RLC layer can operate in an acknowledged mode (AM), an unacknowledged mode (UM), or a transparent mode (TM). In AM, buffering is performed at the transmitter and the receiver. Segmentation is performed at the transmitter and reassembly is performed at the receiver. A feedback mechanism (including an acknowledgment (ACK) or a negative ACK (NACK) is used for communication (such as RLC PDUs or RLC SDUs). AM may be used for certain signaling radio bearers (such as SRB1, SRB2, and SRB3) and data radio bearers. A sequence number in AM, which may be used for reassembly and recovery, can be selected from a 12-bit size or an 18-bit size. In UM, buffering is performed at the transmitter and the receiver, segmentation is performed at the transmitter, reassembly is performed at the receiver, and no feedback mechanism is used. In TM, no RLC header is used, buffering is performed at the transmitter only, no segmentation or reassembly is performed, and no feedback mechanism is used. 
     An RLC transmitter in AM may perform segmentation and concatenation of a packet. The RLC transmitter may add an RLC header to the packet. The RLC transmitter may provide an RLC PDU with the RLC header to the MAC layer. The RLC transmitter may also buffer the RLC PDU in case of a NACK from the RLC receiver. If the RLC transmitter receives a NACK within a period of time, then the RLC transmitter may trigger retransmission of the buffered RLC PDU. 
     The RLC transmitter may use a transmit window to limit the number of RLC SDUs that are transmitted while waiting for an acknowledgment from an RLC receiver. The transmit window may start at the oldest transmitted RLC SDU which has not been fully acknowledged. The oldest transmitted RLC SDU may have been partly acknowledged if it was segmented prior to transmission. The transmit window advances as acknowledgments are received. The size of the transmit window is limited by the sequence number (SN) range. The transmit window is used to prevent SN ambiguity at the RLC receiver. The length of the SN is configured using an RRC parameter. 
     The RLC transmitter can request a status report from an RLC receiver, such as based at least in part on a number of PDUs transmitted since a previous request, or a data volume since a previous request. An RLC parameter pollPDU may indicate the number of PDUs transmitted since a previous request, and an RLC parameter pollByte may indicate the data volume since the previous request. If the RLC transmitter requests and does not receive a status report after waiting a period of time defined by an RLC parameter t-PollRetransmit, the RLC transmitter may retransmit the request. The status report may identify the SNs up to which all RLC SDUs have been successfully received, with the exception of RLC SDUs specified within the remainder of the status report. The status report may indicate to retransmit a complete RLC SDU, or may indicate to retransmit one or more segments of an RLC SDU. 
     An RLC receiver in AM may buffer a received RLC PDU (referred to as an AM data (AMD) PDU) if the RLC PDU is within a receive window, perform reordering, remove the RLC header, and perform reassembly of RLC PDUs to form RLC SDUs. In AM, the RLC receiver may provide feedback regarding reception of RLC PDUs. In AM, each RLC PDU may be transmitted with an SN in ascending order. AM supports automatic repeat request (ARQ). The RLC receiver may transmit a status PDU (sometimes referred to as a status message or a status report) to indicate the status of RLC PDUs at the RLC receiver. The status PDU may indicate which RLC PDU SN(s) were not received by the RLC receiver. For example, the RLC receiver may use a reassembly timer (defined by an RLC parameter t-reassembly). The RLC receiver may start the reassembly timer when a segment of an SDU is received and more segments are pending for that SDU (e.g., if one or more SNs of the SDU are missed). Once the SDU is completely received, the RLC receiver may stop the reassembly timer. If the reassembly timer expires without having received the one or more SNs that were missed, the RLC receiver may transmit a status report indicating one or more segments of the SDU that were not received. For example, the RLC receiver may wait for the length of the reassembly timer (in the hope that a hybrid ARQ (HARQ) mechanism can provide for recovery via retransmission of the one or more SNs that were missed) before transmitting the status report to trigger RLC-layer retransmission of the one or more SNs that were missed. 
     As indicated above,  FIGS.  3 A and  3 B  are provided as one or more examples. Other examples may differ from what is described with regard to  FIGS.  3 A and  3 B . 
       FIGS.  4 A- 4 C  are diagrams illustrating examples of carrier aggregation, in accordance with the present disclosure. 
     Carrier aggregation is a technology that enables two or more component carriers (CCs, sometimes referred to as carriers) to be combined (e.g., into a single channel) for a single UE  120  to enhance data capacity. As shown, carriers can be combined in the same or different frequency bands. Additionally, or alternatively, contiguous or non-contiguous carriers can be combined. A base station  110  may configure carrier aggregation for a UE  120 , such as in a radio resource control (RRC) message, downlink control information (DCI), and/or another signaling message. 
     As shown in  FIG.  4 A , and by reference number  405 , in some aspects, carrier aggregation may be configured in an intra-band contiguous mode where the aggregated carriers are contiguous to one another and are in the same band. As shown in  FIG.  4 B , and by reference number  410 , in some aspects, carrier aggregation may be configured in an intra-band non-contiguous mode where the aggregated carriers are non-contiguous to one another and are in the same band. As shown in  FIG.  4 C , and by reference number  415 , in some aspects, carrier aggregation may be configured in an inter-band non-contiguous mode where the aggregated carriers are non-contiguous to one another and are in different bands. 
     In carrier aggregation, a UE  120  may be configured with a primary carrier or primary cell (PCell) and one or more secondary carriers or secondary cells (SCells). In some aspects, the primary carrier may carry control information (e.g., downlink control information and/or scheduling information) for scheduling data communications on one or more secondary carriers, which may be referred to as cross-carrier scheduling. In some aspects, a carrier (e.g., a primary carrier or a secondary carrier) may carry control information for scheduling data communications on the carrier, which may be referred to as self-carrier scheduling or carrier self-scheduling. 
     In some aspects, carrier aggregation may be used across multiple numerologies. A carrier may be configured with a numerology, which may be indicated by an index p. A numerology may indicate a subcarrier spacing (SCS) of the carrier in the frequency domain, as well as other parameters, such as a cyclic prefix length. The SCS may determine the frequency domain bandwidth and the time domain duration of a resource element. In some aspects, a first carrier of a carrier aggregation configuration may have a first numerology (corresponding to a first SCS) and a second carrier of the carrier aggregation configuration may have a second numerology (corresponding to a second SCS). In some aspects, different numerologies may be used in different frequency ranges (which are defined elsewhere herein). For example, FR1 may typically be associated with numerologies μ=0, 1, and 2 (which correspond to SCSs of 15 kHz, 30 kHz, and 60 kHz, respectively), while FR2 may typically be associated with numerologies μ=2, 3, and 4 (which correspond to SCSs of 60 kHz, 120 kHz, and 240 kHz, respectively). Carrier aggregation can be used for carriers in different frequency ranges, such as a first group of carriers in FR1 (associated with numerologies in the range of μ=0, 1, and 2) and a second group of carriers in FR2 (associated with numerologies in the range of μ=2, 3, and 4). 
     As indicated above,  FIGS.  4 A- 4 C  are provided as one or more examples. Other examples may differ from what is described with regard to  FIGS.  4 A- 4 C . 
       FIG.  5    is a diagram illustrating an example  500  of RLC holes in two numerologies and a reassembly timer associated with the RLC holes, in accordance with the present disclosure.  FIG.  5    is an example where a UE  120  may not differentiate which numerology is associated with an RLC hole, and may therefore run reassembly timers in sequence for RLC holes on different numerologies. 
       FIG.  5    illustrates downlink data received at an RLC layer of the UE  120 . The data is associated with two numerologies: a first numerology with a 30 kHz subcarrier spacing associated with a sub6 FR (e.g., FR1) and a second numerology with a 120 kHz subcarrier spacing associated with a mmW FR (e.g., FR2). The first numerology is associated with a longer slot length than the second numerology. Data received in a slot of the first numerology is illustrated by a longer rectangle (such as shown by reference number  505 ) and data received in a slot of the second numerology is illustrated by a shorter rectangle (such as shown by reference number  510 ). It can be seen that there are four of the shorter slots per longer slot, since there are four slots of the second numerology per slot of the first numerology in accordance with the subcarrier spacings. In example  500 , there may be one carrier of the first numerology and one carrier of the second numerology. The carrier of the second numerology may be a time division duplexing (TDD) carrier, as indicated by the uplink slots with the black fill. 
     The data may be received in the form of RLC PDUs. Each RLC PDU may be associated with a sequence number (SN). One or more RLC PDUs may be received per slot. For an example where SNs received in each slot are illustrated, refer to  FIG.  11   . 
     An RLC hole may occur on the carrier associated with the first numerology or the carrier associated with the second numerology. An RLC hole occurs when the UE  120  does not receive one or more RLC PDUs. The UE  120  may determine that an RLC hole has occurred based at least in part on SNs of the RLC PDUs. For example, an RLC hole  515  occurs, meaning that the UE  120  failed to receive one or more RLC PDUs in a slot. The UE  120  may identify the RLC hole  515  at the time shown by reference number  520 , since at that time, the UE  120  will have received one or more RLC PDUs with higher SNs than the one or more missed RLC PDUs, and can thus determine that the one or more missed RLC PDUs were missed. “RLC hole” is used interchangeably with “RLC discontinuity” herein. 
     The UE  120  may start a reassembly timer, shown by reference number  525 . As the reassembly timer runs, the UE  120  may buffer received data (e.g., on the slot shown by reference number  505 , the slot shown by reference number  510 , and so on). In some cases, the UE  120  may successfully resolve the RLC hole  515 , such as based at least in part on RLC PDUs being received out of order and subsequently reordered, or based at least in part on a HARQ mechanism. If the UE  120  resolves the RLC hole  515 , then the UE  120  may not transmit a NACK regarding the RLC hole  515 . 
     If the reassembly timer associated with the RLC hole  515  elapses and the UE  120  has not resolved the RLC hole  515 , the UE  120  may transmit a NACK regarding the RLC hole  515 , such as at a time shown by reference number  525 . For example, the UE  120  may transmit an RLC status report indicating a NACK regarding the RLC hole  515 . In example  500 , the RLC status report may indicate a most recent successfully received SN, and may indicate one or more SNs of the one or more missed RLC PDUs of the RLC hole  515 . 
     As further shown in example  500 , another RLC hole  530  may occur in the slot shown by reference number  505 . This RLC hole  530  may occur on the carrier associated with the first numerology. The UE  120  may identify the RLC hole  530  at the time shown by reference number  535 . However, in example  500 , since the UE  120  is already running a reassembly timer associated with the RLC hole  515 , the UE  120  may wait to start a reassembly timer for the RLC hole  530  until the reassembly timer associated with the RLC hole  515  has ended. Thus, the UE  120  may continue to buffer communications during both reassembly timers, which may use significant buffer resources of the UE  120 . 
     In some aspects, the UE  120  may switch to a fast NACK mode based at least in part on memory usage of the UE  120  satisfying a threshold. For example, if Layer 2 (RLC) memory usage exceeds a threshold, the UE  120  may enter a fast NACK mode. The fast NACK mode may be associated with a less aggressive mode and a more aggressive mode, as described below. In the fast NACK mode, the UE  120  may shorten the reassembly timer and a t-statusProhibit timer, such that buffering is shorter and memory usage is decreased. The fast NACK mode may use a conservative assumption to set RLC parameters (e.g., RLC timers) such as the length of the reassembly timer. For example, if the UE  120  communicates using an FR1 numerology and an FR2 numerology (as in example  500 ), the fast NACK mode may use the maximum of HARQ round-trip times (RTTs) associated with FR1 and FR2 to set the reassembly timer. Due to this, the reassembly timer may be based at least in part on a HARQ RTT for FR1, which may be too slow for FR2, leading to increased buffer usage. Furthermore, as packet data convergence protocol (PDCP) throughput is high, the UE  120  may quickly move to the more aggressive mode (e.g., within approximately 3 to 4 ms after RLC hole detection). In some examples, the reassembly timer based at least in part on FR1&#39;s HARQ RTT may be 5 to 8 ms. Another 4 ms may elapse from reassembly timer expiry until RLC retransmission is processed at the UE  120 . Thus, in the worst case, the UE  120  may buffer more than 15 MB at a 10 Gbps throughput. In some examples, RLC duplicates on FR2 may be negligible, as the 8 ms reassembly timer may allow up to 5 HARQ transmissions, and throughput loss due to RLC duplicates on FR1 may be expected to be approximately 0.3%. However, even in the more aggressive fast NACK mode, buffer occupancy may remain high (e.g., greater than 50 percent) until an RLC retransmission is transmitted, and for peak bidirectional throughput cases, overall Layer 2 memory usage may remain a concern. 
     Some techniques described herein provide adjustment of an RLC timer (such as a reassembly timer or a status prohibit timer) based at least in part on respective HARQ parameters (such as HARQ RTTs, HARQ recovery delays, or whether HARQ is ongoing for a given set of carriers) and based at least in part on a number of duplicate RLC PDUs received. Furthermore, some techniques described herein provide for the identification of a set of carriers on which an RLC hole occurs. For example, some techniques described herein provide differentiation of whether an RLC hole is associated with a first numerology (e.g., in a first FR) or a second numerology (e.g., in a second FR). In some aspects, the techniques described herein provide for the identification of whether an RLC hole is associated with a set of carriers having a first set of parameters (such as a duplexing configuration, a scheduling delay, a numerology, a frequency range, or an uplink/downlink slot allocation) or a set of carriers having a second set of parameters. By differentiating the set of carriers of the RLC hole, the UE  120  can use RLC parameters that are appropriate for the set of carriers associated with the RLC hole. For example, the UE  120  can use a shorter reassembly timer for RLC holes associated with a higher numerology (and thus a shorter slot length and shorter HARQ RTT) and a longer reassembly timer for RLC holes associated with a lower numerology (and thus a longer slot length and longer HARQ RTT). As another example, the UE  120  may perform RLC status reporting based at least in part on the numerology, such as by selectively acknowledging RLC holes based at least in part on numerologies associated with the RLC holes, as described in connection with  FIG.  6   , or by separately performing RLC status reporting for each numerology, as described in connection with  FIG.  11   . Thus, buffer usage of the UE  120  is reduced, delay associated with RLC reassembly in higher numerologies is reduced, and resource utilization of the UE  120  is improved. For example, for FR2 RLC holes, the reassembly timer may be reduced to approximately 2 to 4 ms, which leads to buffer usage of approximately 12 percent. Furthermore, the reduced memory usage of the UE  120  may mean that this memory can be repurposed for other usages, such as to relax a memory-based cap on an RLC transmit window size for uplink transmission by the UE  120 . As used herein, a lower numerology is associated with a smaller subcarrier spacing. For example, a numerology with a 15 kHz subcarrier spacing is lower than a numerology with a 30 kHz subcarrier spacing, and a numerology with a 120 kHz subcarrier spacing is higher than the numerology with the 30 kHz subcarrier spacing. 
     It should be noted that many of the techniques described herein are described with regard to a combination of carriers of two or more different numerologies. However, these techniques can be applied for combinations of carriers of two or more different sets of parameters, including different duplexing configurations, different scheduling delays, different numerologies, different frequency ranges, different uplink/downlink slot allocations, or a combination thereof. It should be understood that a technique, described herein, as being performed for carriers of two different numerologies can also be performed for carriers of two different sets of parameters, unless noted otherwise. 
     As indicated above,  FIG.  5    is provided as an example. Other examples may differ from what is described with regard to  FIG.  5   . 
       FIG.  6    is a diagram illustrating an example  600  of signaling associated with RLC operation for carrier aggregation with mixed sets of parameters, in accordance with the present disclosure. As shown, example  600  includes a UE  120  and a BS  110 . In example  600 , the BS  110  is an RLC transmitter and the UE  120  is an RLC receiver (e.g., example  600  concerns downlink communication). In some aspects (e.g., for uplink communication), the UE  120  is an RLC transmitter and the BS  110  is an RLC receiver. 
     As shown by reference number  610 , the UE  120  and the BS  110  may communicate using carrier aggregation. For example, the UE  120  and the BS  110  communicate on a first set of carriers (e.g., one or more carriers) in a first frequency range (e.g., FR1) and a second set of carriers (e.g., one or more carriers) in a second frequency range (e.g., FR2). In some aspects, the first set of carriers may be associated with a first numerology and the second set of carriers may be associated with a second numerology different than the first numerology. While the techniques described herein are described with regard to two numerologies, these techniques can be applied for combinations of carriers with any number of different numerologies, or for carriers with the same numerology. For example, the techniques described herein can be performed for combinations of carriers with two or more different sets of parameters, as described elsewhere herein. 
     As shown by reference number  620 , the UE  120  may detect one or more RLC holes. For example, the UE  120  may detect one or more RLC holes on the first set of carriers and/or one or more RLC holes on the second set of carriers. The detection of an RLC hole is described in connection with  FIG.  5   . In some aspects, the UE  120  may detect a single RLC hole. In some aspects, the UE  120  may detect multiple RLC holes. 
     As shown by reference number  630 , the UE  120  may identify whether the one or more RLC holes are in FR1 (e.g., associated with a communication received on the first set of carriers) or in FR2 (e.g., associated with a communication received on the second set of carriers). For example, the UE  120  may determine a numerology associated with each RLC hole of the one or more RLC holes. In some aspects, the UE  120  may identify whether the one or more RLC holes are in FR1 or FR2 based at least in part on correlating a timing of a cyclic redundancy check (CRC) error with an RLC hole, as described in connection with  FIGS.  7 A- 7 C . In some aspects, the UE  120  may identify whether the one or more RLC holes are in FR1 or FR2 based at least in part on correlating TB sizes with RLC holes, as described in connection with  FIGS.  8 - 10   . In some aspects, the UE  120  may identify whether the one or more RLC holes are in FR1 or FR2 based at least in part a combination of the techniques described in connection with  FIGS.  7 A- 10   . 
     As shown by reference number  640 , the UE  120  may transmit an RLC status report based at least in part on identifying whether the one or more RLC holes are in FR1 or FR2. For example, in some aspects, the UE  120  may transmit an RLC status report with a NACK up to the latest RLC hole (e.g., irrespective of whether the latest RLC hole has had sufficient time for HARQ recovery), which may avoid excessive delay for RLC recovery of RLC holes associated with higher numerologies at the cost of potential loss of data associated with RLC holes of lower numerologies. In some aspects, the UE  120  may transmit an RLC status report indicating a NACK for each RLC hole, associated with a first numerology, until a next RLC hole associated with a second numerology. For example, the UE  120  may transmit an RLC status report indicating one or more NACKs for one or more RLC holes associated with FR2 that occur before a next RLC hole associated with FR1 (e.g., based at least in part on identifying whether the one or more RLC holes are associated with FR1 or FR2), which may reduce delay associated with RLC recovery of FR2 RLC holes while allowing sufficient time for RLC recovery of FR1 RLC holes. 
     In some aspects, the UE  120  may transmit an RLC status report indicating a NACK for any RLC hole for which HARQ recovery is expected to be complete. For example, the UE  120  may determine a numerology associated with an RLC hole, as described in connection with reference number  630 . The UE  120  may use a timer associated with the numerology that indicates a length of time after which HARQ recovery is expected to be complete. For a numerology in FR1, the timer may be expressed as t FR1   harq =t-reassembly−k 1 *RTT(FR1), where k 1  is an integer that indicates a typical maximum number of HARQ retransmissions needed to recover an FR1 RLC hole. For a numerology in FR2, the timer may be expressed as t FR2   harq =t-reassembly−k 2 *RTT(FR2), where k 2  is an integer that indicates a typical maximum number of HARQ retransmissions needed to recover an FR2 RLC hole. The UE  120  may start these timers upon starting the reassembly timer associated with an RLC hole. For example, for an RLC hole on either FR1 or FR2, the UE  120  may start both t FR1   harq  and t FR2   harq . The UE  120  may mark the highest RLC hole on each numerology when the respective timer expires. Upon expiry of the reassembly timer, the UE  120  may prepare an RLC status report that indicates a NACK for each marked RLC hole, and each RLC hole that precedes each marked RLC hole. It may be expected that HARQ recovery has failed for each of these RLC holes, so the UE  120  can safely provide a NACK for each of these RLC holes. RLC holes after the marked RLC hole may still be recovered using HARQ recovery, so the UE  120  may not provide a NACK for these RLC holes. Thus, by determining the numerology associated with each RLC hole, the UE  120  can selectively indicate a NACK for each RLC hole based at least in part on a timer associated with an expected HARQ recovery, which reduces buffer usage and delay associated with recovery of higher numerologies. 
     In some aspects, the UE  120  may transmit an RLC status report without having determined a numerology associated with an RLC hole. For example, the RLC status report may be based at least in part on a reassembly timer, as described elsewhere herein. In some aspects, the reassembly timer may be determined (e.g., statically) based at least in part on the numerologies of a number of sets of carriers. For example, the reassembly timer may be expressed as t-reassembly=min(RRC t-reassembly, max(k 1 *HARQ_RTT(μ 1 ), k 2 *HARQ_RTT(μ 2 ), . . . , k n *HARQ_RTT(μ n )), where μ 1 , μ 2 , . . . , μ n  denote numerologies of n set of carriers, and k 1 , k 2 , . . . , k n  denote a maximum number of HARQ retransmissions to wait for each carrier of each numerology n before transmitting an RLC status report indicating a NACK. In some aspects, k 1 , k 2 , . . . , k n  may be determined based at least in part on a number of HARQ transmissions performed to recover an RLC hole (which may be quantified as the number of HARQ RTTs that the UE  120  will wait before sending a NACK, and which may be referred to herein as a HARQ parameter) and a number of RLC duplicates. For example, k 1 , k 2 , . . . , k n  may be determined such that a balance is achieved between the number of HARQ transmissions and the number of RLC duplicates. In this example, an RLC timer (e.g., a reassembly timer or a prohibit timer) that is relatively shorter may result in a quicker NACK transmission, but may increase the rate of RLC duplicates. An RLC timer that is relatively longer (compared to the relatively shorter RLC timer) may reduce the rate of RLC duplicates but may delay NACK. The UE  120  or the base station  110  may determine k 1 , k 2 , . . . , k n  based at least in part on the number of HARQ transmissions and the number of RLC duplicates, as described elsewhere herein. 
     In some aspects, the reassembly timer may be determined (e.g., semi-statically) based at least in part on which configured carriers (of the first set of carriers and the second set of carriers) are active for downlink scheduling. For example, the UE  120  may identify a set L of all carriers with a scheduled physical downlink shared channel (PDSCH). If all carriers of L have the same numerology, then the UE  120  may set the reassembly timer as t-reassembly=min(RRC t-reassembly, k*HARQ_RTT (μ)). If two or more carriers of L have n different numerologies (where n is greater than 1), then the UE  120  may set the reassembly timer as t-reassembly=min(RRC t-reassembly, max(k 1 *HARQ_RTT(μ 1 ), k 2 *HARQ_RTT(μ 2 ), . . . , k n *HARQ_RTT(μ n )), as described above. The UE  120  may update L semi-statically, such as based at least in part on an RRC update, a DCI update, or the like. 
     In some aspects, the BS  110  and the UE  120  may perform per-numerology RLC status reporting. For example, the BS  110  may maintain per-numerology queues for transmitted RLC PDUs and PDUs to be retransmitted. The BS  110  may maintain a common queue for incoming PDCP PDUs (e.g., incoming to the RLC layer) until the incoming PDCP PDUs are transmitted on a CC associated with a given numerology. The UE  120  may track RLC SNs per numerology. For example, the UE  120  may track RLC SNs received on a given numerology. In some aspects, the UE  120  may detect a numerology of an RLC hole, such as using the techniques described in connection with  FIGS.  7 - 8   . In some aspects, for a mixed RLC hole, the UE  120  may consider the mixed RLC hole to be associated with a lowest numerology of the numerologies associated with the mixed RLC hole. The UE  120  and the BS  110  may use numerology-specific RLC parameters (such as a reassembly timer, a t-statusProhibit timer, a pollPDU parameter, a pollBytes parameter, a t-PollRetransmit parameter, or the like), which may be specified via RRC signaling for uplink and downlink communications of the UE  120 . The UE  120  (or an RLC receiver) may transmit an RLC status report for a given numerology upon receiving a poll PDU for the given numerology or upon a reassembly timer for the given numerology expiring. In the RLC status report, the RLC receiver may indicate a highest RLC SN received on the given numerology (such that there is no ambiguity regarding whether the highest RLC SN is associated with the given numerology or another numerology. The BS  110  (or an RLC transmitter) can determine the numerology associated with the RLC status report by reference to the highest RLC SN (since the highest RLC SN was transmitted by the BS  110 ). In this way, the UE  120  may identify one or more numerologies in which an RLC hole occurred. The one or more numerologies may include a single numerology (e.g., only a single numerology) if the RLC hole is a pure RLC hole, and may include multiple numerologies if the RLC hole is a mixed RLC hole. Thus, the UE  120  and the BS  110  may implement numerology-specific RLC status reporting, which reduces buffer utilization and increases speed of RLC recovery for higher frequency ranges. 
     As indicated above,  FIG.  6    is provided as an example. Other examples may differ from what is described with regard to  FIG.  6   . 
       FIGS.  7 A- 7 C  are diagrams illustrating examples of identifying a numerology associated with an RLC hole based at least in part on correlating timing of CRC errors with RLC holes, in accordance with the present disclosure. While  FIGS.  7 A- 7 C  are primarily described with regard to a first numerology and a second numerology, the techniques described with regard to  FIGS.  7 A- 7 C  can be used to identify which configuration, of a first configuration and a second configuration, is associated with an RLC hole. The configurations are described in more detail elsewhere herein. 
       FIG.  7 A  illustrates communications on a CC0 and a CC1. Communications on CC0 are illustrated by downward solid (undashed) arrows. Communications on CC1 are illustrated by downward dashed arrows. Each communication may include a number of RLC PDUs. For example, each communication may represent one or more TBs which may be associated with a number of RLC PDUs. Thus, the UE may receive RLC PDUs. An RLC PDU may be associated with a sequence number. In some aspects, some number of the RLC PDUs may be RLC duplicates. An RLC duplicate may be caused when an RLC layer transmits a NACK for a communication that was successfully received by the UE. For example, if a shorter reassembly timer is used, the UE may determine that an RLC PDU was missed when the RLC PDU is in fact associated with a longer slot length, meaning that the RLC layer has not yet received the successfully received RLC PDU. In some aspects, the UE may receive some number of RLC duplicates. For example, the UE may receive non-duplicate RLC PDUs and duplicated RLC PDUs (i.e., RLC duplicates). The UE may identify RLC duplicates, for example, based at least in part on a sequence number of the RLC duplicate being associated with at least two received RLC PDUs (of which at least one is associated with a retransmission of an initial transmission of the RLC PDU). In some aspects, the UE  120  may adjust an RLC timer, such as a reassembly timer or a prohibit timer, based at least in part on the number of RLC duplicates, such as based at least in part on identifying a ratio of RLC duplicates to non-duplicates, a threshold number of RLC duplicates being received, or the like, as described in more detail elsewhere herein. 
     CC0 is associated with a higher numerology than CC1. For example, CC0 may belong to the second set of carriers of  FIG.  6   , and CC1 may belong to the first set of carriers of  FIG.  6   . In some aspects, CC0 may be associated with a 120 kHz subcarrier spacing and CC1 may be associated with a 30 kHz subcarrier spacing. In  FIG.  7 A , slot boundaries are aligned across component carriers. Thus, the UE  120  can perform a one-to-one mapping of RLC holes and HARQ errors. In  FIG.  7 A , RLC SNs in each TB are assumed to be contiguous. 
     Reference number  705  shows slots of CC0 and CC1. In  FIG.  7 A , the slots are aligned. As in  FIG.  5   , white fill with black dots indicates an RLC hole in CC0 (e.g., associated with the numerology and/or FR of CC0) and diagonal fill indicates an RLC hole in CC1 (e.g., associated with the numerology and/or FR of CC1). Furthermore, a black fill indicates an uplink slot of a TDD carrier. As shown, an RLC hole  710  occurs at time t 1  and an RLC hole  715  occurs at time t 7  on CC0, and an RLC hole  720  occurs at time t 4  on CC1. The UE  120  may have a capability to identify the RLC hole  710  after t 3 , the RLC hole  715  after t 8  (e.g., after a communication subsequent to t 8  is received on CC0), and the RLC hole  720  after t 8  (e.g., after a communication subsequent to t 8  is received on CC0). 
     Reference number  725  shows RLC holes as identified by the UE  120 . For example, the UE  120  may determine a set of carriers L1 that have a new HARQ transmission in a slot X. For carriers in L1, at the end of slot X, the UE  120  may identify a set of carriers L2 associated with a CRC failure. The set of carriers L2 is a set of carriers associated with an RLC hole. As shown by reference number  730 , in some aspects, the UE  120  may identify a pure RLC hole, such as the pure RLC hole in slot X. A pure RLC hole is an RLC hole (or a group of RLC holes) that is associated with a single numerology. For example, the UE  120  may determine that all carriers in L2 have the same numerology, and may thus identify a pure RLC hole. For a pure RLC hole, the UE  120  may set a reassembly timer as t-reassembly=min(RRC t-reassembly, k*HARQ_RTT(μ)), where k is an integer indicating a maximum number of HARQ retransmissions, such that RLC recovery is delayed to allow for HARQ recovery. 
     As shown by reference number  735 , in some aspects, the UE  120  may identify a mixed RLC hole. A mixed RLC hole occurs when two RLC holes at least partially overlap each other and are associated with different configurations (e.g., different numerologies). For example, the UE  120  may identify a mixed RLC hole when carriers of L2 have different configurations. The UE  120  may set the reassembly timer as t-reassembly=min(RRC t-reassembly, k*max(HARQ_RTT(μ))), where μ denotes the set of numerologies of carriers in L2. 
     In some aspects, RLC SNs in a TB may be out of order. For example, out-of-order SNs in an FR1 TB (such as the TB shown by reference number  740  of  FIG.  7 B ) may result in SN discontinuity across TBs of FR2 (such as the TBs shown by reference numbers  745  and  750 ), and may or may not result in discontinuity within a TB of FR2. If an RLC hole is detected without a HARQ error, then the UE  120  may determine that the RLC hole is due to out-of-order SN(s). If the UE  120  detects an RLC hole with a corresponding HARQ error in the slot, in some aspects, the UE  120  may wait for a length of time for out-of-order SNs to arrive before identifying the numerology associated with the RLC hole. 
       FIGS.  7 B and  7 C  illustrate identifying a numerology associated with an RLC hole with misaligned slot boundaries between carriers.  FIG.  7 B  is an example where there is less than 1 slot of timing difference between CCs, and  FIG.  7 C  is an example where there is more than 1 slot of timing difference between CCs. As shown, in  FIG.  7 B , CC1&#39;s slot boundaries are later than CC0&#39;s slot boundaries by less than the length of a slot on CC0. Thus, the starting boundary of slot 0 on CC1 is at t 0 ′, while the starting boundary of slot 0 on CC0 is at t 0 . In  FIG.  7 C , CC1&#39;s slot boundaries are later than CC0&#39;s slot boundaries by more than the length of a slot on CC0. Thus, the starting boundary of slot 0 on CC1 is at t 1 ′, while the starting boundary of slot 0 on CC0 is at to. The unaligned slot boundaries may cause out-of-order SN reception, which may lead to a false detection of an FR1 hole. For example, as shown by reference number  755  of  FIG.  7 C , the UE  120  may not receive SNs of the slot on CC1 ending at t 5 ′ until after the end of the slot on CC0 ending at t 5 , leading to false detection of an RLC hole on CC1. Furthermore, as shown by reference number  760 , the UE  120  may detect a mixed hole on CC0 and CC1 due to out-of-order SNs of CC1 being received more than one slot after SNs on CC0. 
     In some aspects, the UE  120  may wait for a time offset  6  before identifying a numerology associated with a detected RLC hole. By waiting for the time offset, the UE  120  may allow out-of-order SNs to be received before attempting to identify the numerology, which reduces the occurrence of false RLC hole detection, thereby improving RLC recovery for FR2 carriers. Furthermore, by using the time offset, performance with misaligned slot boundaries may be approximately equivalent to performance with aligned slot boundaries. 
     As indicated above,  FIGS.  7 A- 7 C  are provided as examples. Other examples may differ from what is described with regard to  FIGS.  7 A- 7 C . 
       FIG.  8    is a diagram illustrating an example  800  of identifying a numerology associated with an RLC hole based at least in part on correlating a TB size with an RLC hole, in accordance with the present disclosure.  FIG.  8    illustrates communications on a CC0, a CC1, and a CC2 of a mmW numerology (e.g., FR2), and a CC3 and a CC4 of a sub6 numerology (e.g., FR1). The mmW numerology is higher than the sub6 numerology. For example, CC0, CC1, and CC2 may belong to the second set of carriers of  FIG.  6   , and CC3 and CC4 may belong to the first set of carriers of  FIG.  6   . In some aspects, CC0 may be associated with a 30 kHz subcarrier spacing and CC1 may be associated with a 120 kHz subcarrier spacing. In example  800 , slot boundaries are aligned across component carriers. While  FIG.  8    is primarily described with regard to a first numerology and a second numerology, the techniques described with regard to  FIG.  8    can be used to identify which configuration, of a first configuration and a second configuration, is associated with an RLC hole. The configurations are described in more detail elsewhere herein. 
     Let X and Y be an estimated TB size for the mmW numerology and the sub6 numerology, respectively. In a case where the same bandwidth and modulation and coding scheme (MCS) for each CC (for simplicity of illustration), and assuming a 30 kHz subcarrier spacing for the sub6 numerology and a 120 kHz subcarrier spacing for the mmW numerology, then Y is approximately equal to 4×. For simplicity, in example  800 , the estimated TB size of a TB is equal to the sum of all RLC PDUs in the TB. In some aspects, the UE  120  may allow for an ambiguity margin of some number of bytes in case the estimated TB size of the TB is not exactly equal to the sum of all RLC PDUs in the TB. 
     Reference number  805  illustrates the estimated TB size as received at the RLC layer in each time interval corresponding to a slot on one of the CCs. For example, “3×,” at time t 0 −t 1 , indicates that three TBs of size X were received in the first slot. 
     The UE  120  may identify RLC holes in the time intervals  810 ,  815 ,  820 , and  825 . In the time interval  810 , the UE  120  identifies an estimated TB size of 2× since an RLC hole occurred on CC1. The time interval  810  does not take into account the data of CC1 because the reception of the data of CC4 is not complete until t 4 . Based at least in part on the estimated TB size of 2×, the UE  120  may determine that the RLC hole is associated with the mmW numerology, and may determine an appropriate reassembly timer accordingly. Similarly, at the time interval  815 , the UE  120  identifies an estimated TB size of 4×since an RLC hole occurred on CC3, and each of CC0, CC1, and CC2 have uplink slots ending at t 4 . Thus, the UE  120  may determine that the RLC hole is associated with the sub6 numerology, and may determine an appropriate reassembly timer accordingly. Similarly, at the time interval  820 , the UE  120  identifies an estimated TB size of X since RLC holes occurred on CC0 and CC2. Thus, the UE  120  may determine that the RLC hole is associated with the mmW numerology, and may determine an appropriate reassembly timer accordingly. Similarly, at the time interval  820 , the UE  120  identifies an estimated TB size of 3×since RLC holes occurred on CC3 and CC4. Thus, the UE  120  may determine that the RLC holes are associated with the sub6 numerology, and may determine an appropriate reassembly timer accordingly. The UE  120  may perform such determinations based at least in part on an estimated or configured TB size per CC, a set of CCs with ongoing downlink scheduling, a downlink/uplink TDD pattern for each CC (which defines whether each slot or symbol is for downlink or uplink communication), and relative slot timing of the CCs. 
     As indicated above,  FIG.  8    is provided as an example. Other examples may differ from what is described with regard to  FIG.  8   . 
       FIG.  9    is a diagram illustrating an example  900  of ambiguity associated with an RLC hole. 
     In some cases, ambiguity may occur with regard to whether an RLC hole is associated with a first numerology or a second numerology. For example, when the sum of the number of TBs associated with a first numerology is approximately equal to the sum of the number of TBs associated with a second numerology, confusion may arise. As an example, example  900  includes five CCs associated with the mmW numerology and two CCs associated with the sub6 numerology. As shown by reference number  910 , a mixed RLC hole involving an RLC hole on one of the five CCs and an RLC hole on one of the two CCs may overlap in time. In this case, the UE  120  may have difficulty identifying that there is one RLC hole associated with each numerology. For example, the TB size of 8× in this situation could correspond to all of the five CCs having an RLC hole and none of the two CCs having an RLC hole, or to one of the five CCs having an RLC hole and one of the two CCs having an RLC hole, which may lead to an inappropriate reassembly timer being used. As another example, shown by reference number  920 , a pure RLC hole on one of the two CCs can be mistaken for a mixed hole occurring on four of the five mmW CCs. For example, the TB size of 8× in this situation could correspond to four of the five CCs having an RLC hole and neither of the two CCs having an RLC hole. In this situation, in some aspects, the UE  120  may use the techniques described with regard to  FIGS.  7 A- 7 C  to resolve the ambiguity. 
     As indicated above,  FIG.  9    is provided as an example. Other examples may differ from what is described with regard to  FIG.  9   . 
       FIG.  10    is a diagram illustrating an example  1000  of identifying a numerology associated with an RLC hole based at least in part on correlating a transport block size with an RLC hole with a timing mismatch, in accordance with the present disclosure. While  FIG.  10    is primarily described with regard to a first numerology and a second numerology, the techniques described with regard to  FIG.  10    can be used to identify which configuration, of a first configuration and a second configuration, is associated with an RLC hole. The configurations are described in more detail elsewhere herein. 
     In some aspects, slot boundaries of CCs may be misaligned. For example, as shown by reference number  1010 , slot boundaries may be misaligned between CCs of a first numerology and between CCs of a second numerology. In this example, CC3 of the mmW FR is ahead of other CCs of the mmW FR, and CC0 of the sub6 FR is ahead of CC0 of the sub6 FR. The UE  120  may perform per-transmission time interval (per-TTI) processing to align CCs of a given numerology. For example, as shown, the UE  120  align each of the CCs of the mmW FR with each other, and may align each of the CCs of the sub6 FR with each other. In this case, CCs of different numerologies can still be misaligned with each other, which may lead to misidentification of an RLC hole. For example, the UE may identify an RLC hole between t 4  and t 5  associated with the two CCs of the sub6 FR. In some aspects, the UE  120  may wait for a time offset  6  before identifying a numerology associated with a detected RLC hole using the techniques of  FIG.  10   . For example, 6 may be at least as long as the misalignment between the sub6 FR&#39;s CCs and the mmW FR&#39;s CCs (in this example, at least t 5 ′−t 5 ). By waiting for the time offset, the UE  120  may allow out-of-order SNs to be received and reordered (e.g., within a numerology) before attempting to identify the numerology, which reduces the occurrence of false RLC hole detection, thereby improving RLC recovery for FR2 carriers. Here, the UE  120  may identify the RLC size of 8× after t 5 ′, and may identify the RLC size of X after t 5 . Thus, the UE may determine that there is no RLC hole in the sub6 FR&#39;s CCs and that there are three RLC holes in the mmw FR&#39;s CCs. Furthermore, by using the time offset, performance with misaligned slot boundaries may be approximately equivalent to performance with aligned slot boundaries. 
     As indicated above,  FIG.  10    is provided as an example. Other examples may differ from what is described with regard to  FIG.  10   . 
       FIG.  11    is a diagram illustrating an example  1100  of independent RLC status reporting regarding a first numerology and a second numerology using reassembly timers running in parallel, in accordance with the present disclosure. Example  1100  shows data received by a UE  120  on a first carrier, associated with a first numerology, and a second carrier associated with a second numerology. For example, the first carrier may have a numerology associated with a subcarrier spacing of 30 kHz and the second carrier may have a numerology associated with a subcarrier spacing of 120 kHz. RLC SNs of TBs received in each slot are shown as numbers included in each block. For example, in a first slot of the second carrier, the UE may receive RLC SNs 31-40. In a first slot of the first carrier (if an RLC hole  1105  did not occur), the UE may receive RLC SNs 41-80. Example  1100  illustrates how a UE  120  and a BS  110  can maintain per-numerology RLC reassembly timers and RLC status reporting. While  FIG.  11    is primarily described with regard to a first numerology and a second numerology, the techniques described with regard to  FIG.  11    can be applied for multiple configurations, which are described in more detail elsewhere herein. Example  1100  shows how a UE  120  can run, in parallel, the t-reassembly timer per numerology (e.g., per configuration) and can perform independent status reporting for each numerology. The techniques described with regard to example  1100  may involve minimal modification to a wireless communication specification. 
     As shown, the UE  120  may identify an RLC hole  1105  associated with an FR1 numerology. The UE  120  may determine that the RLC hole  1105  is associated with the FR1 numerology using one or more of the techniques described with regard to  FIGS.  7 - 10   . As shown, the RLC hole  1105  may impact RLC SNs 41-80. Accordingly, the UE  120  may start a reassembly timer  1110  after detecting the RLC hole  1105  (e.g., after a subsequent slot including RLC SNs 81-90). The reassembly timer  1110  may be associated with the FR1 numerology. For example, the reassembly timer  1110  may have a length associated with the FR1 numerology. 
     As further shown, the UE  120  may identify an RLC hole  1115  associated with an FR2 numerology. The UE  120  may determine that the RLC hole  1115  is associated with the FR2 numerology using one or more of the techniques described with regard to  FIGS.  7 - 10   . As shown, the RLC hole  1115  may impact RLC SNs 91-100. Accordingly, the UE  120  may start a reassembly timer  1120  after detecting the RLC hole  1115  (e.g., after a subsequent slot including RLC SNs 101-110). The reassembly timer  1120  may be associated with the FR2 numerology. For example, the reassembly timer  1120  may have a length associated with the FR2 numerology. Furthermore, the UE  120  may start the reassembly timer  1120  before the reassembly timer  1110  has elapsed, which reduces FR2 recovery time relative to running the reassembly timer  1110  and then the reassembly timer  1120  in sequence. As shown by reference number  1125 , the reassembly timer  1120  may elapse before the reassembly timer  1110 , such that FR2 recovery can be completed before FR1 recovery. Thus, the UE  120  may buffer only for the length of the longer reassembly timer (e.g., the reassembly timer  1110  associated with the FR1 numerology) rather than the combined length of the reassembly timers. 
     As shown by reference number  1130 , the UE  120  may transmit an RLC status report based at least in part on the reassembly timer  1120  expiring. The RLC status report may indicate an ACK for a most recently received SN (e.g., SN number  170 ), and may indicate a NACK for the FR2 RLC hole (e.g., based at least in part on the reassembly timer  1120  being associated with the FR2 numerology). Notably, the RLC status report is transmitted before the reassembly timer  1110  has elapsed, thereby expediting the recovery of the RLC hole  1115 . Thus, the worst case PDCP buffer requirement is max(t-reassembly for all μ)*total_DL_Tput. 
     As shown by reference number  1135 , the UE  120  may receive an RLC poll associated with the FR2 numerology. As shown by reference number  1140 , the UE  120  may transmit an RLC status report indicating an ACK up to a most recently received RLC SN (e.g., RLC SN 200) irrespective of the state of the reassembly timer  1110 . For example, the UE  120  may acknowledge higher RLC SNs on FR1 than a highest RLC SN before a NACK on FR1 (associated with the RLC hole  1105 ). As shown by reference number  1145 , the UE  120  may receive an RLC poll associated with the FR1 numerology. As shown by reference number  1150 , the UE  120  may transmit an RLC status report indicating an ACK up to a most recent RLC hole (e.g., the RLC hole  1115 ) (e.g., indicating an RLC SN less than 41, corresponding to whatever RLC SN was most recently received on the FR1 numerology). 
     As shown by reference number  1155 , upon expiration of the reassembly timer  1110 , the UE  120  may transmit an RLC status report associated with the FR1 numerology (since the reassembly timer  1110  is associated with the FR1 numerology). As further shown, the RLC status report may indicate an ACK for a most recently received FR1 RLC SN (e.g., RLC SN number  240 ) and a NACK for the RLC hole  1105 . 
     In some aspects, the UE  120  (or an RLC receiver) may mistake an RLC hole associated with RLC SN X in FR2 for an RLC hole in FR1. The buffer of the FR1 transmit window may grow undesirably until the reassembly timer expires, since the FR1 status for each FR1 poll PDU may have an acknowledged SN that is lower than X. It may be likely that the BS  110  (or an RLC transmitter) transmits a poll PDU on FR2 before the RLC hole in FR2 is filled by sending NACK in FR1 status when FR1 t-reassembly expires, since the reassembly timer for FR1 is longer than for FR2. Therefore, since no NACK is transmitted for the RLC hole in FR2 (since the UE  120  has mistaken this RLC hole as being associated with FR1), the BS  110  may discard data associated with the RLC hole. To avoid this data discard, the UE  120  may transmit a NACK for the RLC hole irrespective of whether a poll PDU is associated with FR1 or FR2. For example, the UE  120  may transmit a NACK for an RLC hole associated with any numerology, irrespective of the numerology associated with a poll PDU or a reassembly timer that triggers the NACK. The above technique is also applicable for an RLC hole in FR1 being mistaken for an RLC hole in FR2. 
     As indicated above,  FIG.  11    is provided as an example. Other examples may differ from what is described with regard to  FIG.  11   . 
       FIG.  12    is a diagram illustrating an example  1200  of RLC hole detection for a leading carrier and a lagging carrier. Example  1200  illustrates an RLC entity receiving traffic associated with a first carrier and a second carrier. RLC SNs received in a given slot are denoted by an upward arrow indicating the number of the slot (e.g., slot n, slot n+1, and so on), and the RLC SNs received in that slot. Solid upward arrows indicate communications received via a first carrier and dashed upward arrows indicate communications received via a second carrier. The first carrier may be associated with a first set of parameters (e.g., a first configuration) and the second carrier may be associated with a second set of parameters (e.g., a second configuration). For example, the first set of parameters and the second set of parameters may indicate at least one of a HARQ parameter (e.g., a HARQ round trip time, a HARQ recovery delay), a duplexing configuration (e.g., TDD or FDD), a scheduling delay, a numerology, a bandwidth, a frequency range, an uplink/downlink slot allocation (e.g., a TDD downlink/uplink slot configuration, a slot format indication), or a combination thereof. A rectangle within the rectangle indicating the RLC entity indicates traffic associated with a slot as received by the RLC entity. It should be noted that the traffic received by the RLC entity is not shown in order with regard to time. For example, the RLC entity may receive RLC SNs 2000-2500 at substantially the same time as receiving RLC SNs 0-20, or prior to receiving RLC SNs 21-40. 
     As shown by reference number  1205 , in a slot n, the RLC entity may receive RLC SNs 0-20 on the first carrier and SNs 2000-2500 on the second carrier. As further shown, on the first carrier, the RLC entity may receive SNs 21-40 in slot n+1, SNs 41-60 in slot n+2, and SNs 61-100 in slot n+1. For example, the first carrier and the second carrier may be associated with different sets of parameters such that the RLC entity receives a larger number of RLC PDUs on the second carrier in a given slot. As another example, the second carrier may be configured such that TBSs are received less frequently on the second carrier. Thus, the first carrier may take multiple transmission time intervals (TTIs) to reach the RLC SN of the second carrier. For example, it can be seen that the first carrier may require a large number of slots to transmit enough RLC PDUs for the RLC SNs of the first carrier (e.g., 0-20, 21-40, and so on) to reach the RLC SNs of the second carrier transmitted in slot n (e.g., 2000-2500). Thus, the first carrier may be referred to as a lagging carrier and the second carrier may be referred to as a leading carrier. This delay in the convergence may be exacerbated by a block error rate (BLER) for hybrid automatic repeat request (HARQ) feedback or retransmissions, as well as network scheduler implementation configurations. 
     As described above, from the RLC entity&#39;s perspective, the UE may receive packets with RLC SNs (or PDCP SNs) spread out considerably. For example, higher range RLC SNs (such as RLC SNs 2000-2500, shown by reference number  1210 ) will be received from the leading carrier while lower range RLC SNs (such as RLC SNs 0-100, of which RLC SNs 0-20 are shown by reference number  1215 ) are filled from the lagging carrier in the same TTI. This issue can also arise for any number of carriers and an SN gap of any value that cannot be received or recovered via HARQ within a configured RLC reassembly timer. If there is residual HARQ BLER which is common in field, HARQ recovery delay can exacerbate the issue. 
     As shown by reference number  1220 , the RLC entity may detect an RLC hole based at least in part on RLC SN 2000 being received before RLC SN 21 through 1999. Thus, the RLC entity may start a reassembly timer. Once the reassembly timer expires, as shown by reference number  1225 , the RLC entity may transmit an RLC status report reporting a NACK for a subset of RLC SNs that are not scheduled for new transmission or for which HARQ recovery is unfinished. If the gap between the RLC SNs of the second carrier (starting at RLC SN 2000) and the RLC SNs of the first carrier (starting at RLC SN 0) is sufficiently large, then the subset of RLC PDUs between RLC SN 20 and RLC SN 2000 may be lost. For example, if the reassembly timer is shorter than the time required to receive or schedule RLC SNs 21-1999, then the RLC may perform automatic repeat request (ARQ) recovery for the subset of RLC SNs 21-1999 before the subset has been transmitted to the UE, thereby introducing delay in receiving the subset. A BLER in the physical channel may exacerbate the delay since the retransmission may take additional attempts. 
     After the UE transmits the RLC status report, the UE may receive an initial transmission of RLC PDUs corresponding to the subset of RLC SNs indicated by the RLC status report. Thus, the UE may advance an RLC receive window, since an RLC hole corresponding to the subset of RLC SNs is considered filled. However, the network may respond to the RLC status report by retransmitting the RLC PDUs corresponding to the subset of RLC SNs, which the UE may drop upon receipt, since the RLC receive window has already been advanced past the subset of RLC SNs. 
     This sequence of events may use uplink bandwidth due to transmission of RLC status PDUs transmitted because of the configured reassembly timer value being unable to cover the inter-CC delay in network scheduling between the first carrier and the second carrier and/or HARQ recovery delay thereafter. Furthermore, downlink throughput may be reduced as the retransmitted packets may use bandwidth that could otherwise be used for newer packets, and may consequently be dropped at UE as duplicate packets at the expense of UE power and processor usage. 
     Furthermore, in some cases, the RLC timers (such as reassembly timers and the like) configured by the network may be applicable to all carriers, and may generally be configured to be sufficient for RLC hole recovery on either of the first carrier or the second carrier (that is, the RLC timers may be configured conservatively, as described elsewhere herein). In this case, the leading carrier, which is receiving data at a higher rate, could have a legitimate RLC hole due to BLER, and may wait for the longer period indicated by the RLC timers before sending a NACK to the network, since the RLC timers were configured by the network conservatively in view of all carrier. This can impact the latency of the recovered packets through RLC ARQ. 
     As indicated above,  FIG.  12    is provided as an example. Other examples may differ from what is described with regard to  FIG.  12   . 
       FIG.  13    is a diagram illustrating an example  1300  of RLC timer modification based at least in part on a HARQ latency, in accordance with the present disclosure. Example  1300  illustrates a first trigger condition  1310  and a second trigger condition  1320  associated with modifying an RLC timer, such as a reassembly timer. The first trigger condition  1310  and the second trigger condition  1320  provide conditions that can be used to detect an RLC discontinuity. For example, detecting an RLC discontinuity may include determining that the first trigger condition  1310  is satisfied or that the second trigger condition  1320  is satisfied. The techniques described with regard to example  1300  may be performed by an RLC receiver, such as an RLC receiver of a UE (e.g., UE  120 ). The RLC receiver may be associated with multiple carriers (e.g., two or more carriers) associated with different sets of parameters, as described in more detail in connection with  FIG.  12   . 
     The RLC receiver may track information associated with the first trigger condition  1310  or the second trigger condition  1320 . may track downlink HARQ failure metrics for the multiple carriers (e.g., a number of failed HARQ procedures). As another example, the RLC receiver may track PDCP PDU loss metrics. A PDCP PDU loss metric may indicate a number or ratio of PDCP PDUs considered lost (indicating that RLC layer recovery has failed). As yet another example, the RLC receiver may track a number of RLC PDUs retransmitted (indicating that a NACK was transmitted for the RLC PDUs via an RLC status report or a HARQ procedure). As still another example, the RLC receiver may track a number of RLC PDUs dropped due to being received outside of an RLC receive window or being a duplicate of a received RLC PDU. 
     The first trigger condition  1310  may relate to a number of downlink HARQ failures, a number of dropped retransmissions of RLC PDUs, and a rate of PDCP PDU loss. For example, if the number of downlink HARQ failures is lower than a threshold (in some examples, if there are no downlink HARQ failures), if the number of dropped retransmissions of RLC PDUs satisfies a threshold (in some examples, 90%), and if the rate of PDCP PDU loss is lower than a threshold (in some examples, if there are no PDCP PDU losses), then the RLC receiver may determine that a non-optimal RLC timer is configured. The first trigger condition  1310  may indicate that a reassembly timer (e.g., RLC timer) is not sufficiently long to take into account a difference between a leading carrier and a lagging carrier. For example, the number of downlink HARQ failures being lower than the threshold may indicate that RLC holes are unlikely to arise due to BLER in the physical layer. The number of dropped retransmissions of RLC PDUs satisfying the threshold may indicate that the RLC PDUs have already been successfully received (since an RLC status report NACK was already triggered for the RLC PDUs due to the reassembly timer), and that retransmission of the RLC PDUs was thus frivolous. The rate of PDCP PDU loss being lower than the threshold may indicate that the RLC holes associated with the lagging carrier are being successfully filled, indicating that the RLC holes are caused by the retransmission timer rather than poor channel quality. 
     The second trigger condition  1320  may relate to an inter-carrier RLC SN delay and a HARQ recovery delay. As used herein, a HARQ recovery delay refers to a length of time associated with HARQ recovery of a missed SN. The HARQ recovery delay may start at a first SN of a missed set of SNs, and may extend for a length of time. The HARQ recovery delay may take into account numerology of the carrier associated with the missed set of SNs, a configured number of HARQ retransmission attempts, a downlink/uplink configuration of the carrier associated with the missed set of SNs, or other factors. The inter-carrier RLC SN delay may indicate a time gap between convergence of RLC SNs of a first carrier and RLC SNs of a second carrier. For example, referring to  FIG.  12   , the inter-carrier RLC SN delay may indicate a delay between receiving RLC SN 2000 on the second carrier and receiving RLC SN 1999 on the first carrier. As shown, if the sum of the inter-carrier RLC SN delay and the HARQ recovery delay satisfies a threshold, then the RLC receiver may determine that a non-optimal RLC timer is configured. In some aspects, the threshold may be the length of the reassembly timer. In some other aspects, the threshold may be based at least in part on the length of the reassembly timer. In some aspects, the second trigger condition  1320  may be further based at least in part on a rate of PDCP PDU loss being lower than or equal to a threshold. In some examples, the threshold for the rate of PDCP PDU loss may be zero, such that the second trigger condition  1320  is satisfied if there is no PDCP PDU loss and if the sum of the inter-carrier RLC SN delay and the HARQ recover delay is greater than the reassembly timer. 
     In some aspects, the RLC receiver may determine that a non-optimal RLC timer is configured based at least in part on determining whether HARQ procedures are ongoing for one or more carriers, as described in more detail in connection with  FIG.  16   . 
     As shown by reference number  1330 , the RLC receiver may adjust an RLC timer (such as a reassembly timer or a status prohibit timer) based at least in part on determining that a non-optimal RLC timer is configured (such as based at least in part on the first trigger condition  1310 , the second trigger condition  1320 , or determining whether HARQ procedures are ongoing for one or more carriers). For example, the RLC receiver may perform adaptive RLC timer upscaling. The RLC receiver may determine the RLC timer based at least in part on a number of RLC duplicates (e.g., such that the number of RLC duplicates or a rate of RLC duplication is lower than a threshold). Thus, the RLC receiver may improve bandwidth utilization and reduce the rate of RLC drops. 
     In some aspects, the RLC receiver may increase the length of the RLC timer. For example, the RLC receiver may increment the length of the RLC timer by a step size (in one example, 5 ms) until a trigger condition (such as the first trigger condition  1310  or the second trigger condition  1320 ) is no longer satisfied. In some aspects, the RLC receiver may increase the configured RLC reassembly timer or RLC status prohibit timer in steps of 5 ms until the rate of retransmitted RLC PDUs is minimized (e.g., below a first threshold) while maintaining the rate of PDCP PDU loss at minimum (e.g., below a second threshold). 
     In some aspects, the RLC receiver may determine the length of the RLC timer based at least in part on a model. In some aspects, the model may be trained using a machine learning algorithm. For example, the model may be trained with a set of parameters, and may be used to determine a suitable value for an RLC timer such that RLC holes are properly recovered without erroneously declaring an RLC hole due to a difference in RLC SN arrival time between carriers. In some aspects, the model may be trained to determine a suitable RLC timer value to recover an RLC hole in time, to avoid the dropping of RLC duplicates, to increase the bandwidth utilization, and to keep the PDCP PDU loss at minimum. 
     In some aspects, the set of parameters may include, for example, a length of a configured RLC timer, a length of a configured PDCP timer, an RLC retransmitted PDU count, an RLC PDU drop count, a rate of PDCP PDU loss, downlink HARQ failure information for each carrier, a downlink HARQ recovery timeline for each carrier, a downlink BLER for each carrier, a downlink throughput of each carrier, an inter-carrier RLC SN scheduling delay among carriers, or information indicating one or more carriers that are lagging carriers. In some aspects, the set of parameters may include additional parameters to those described above or alternative parameters to those described above. The model may receive, as input, the set of parameters. In some aspects, the model may output information indicating a modified length of a configured RLC timer. In some aspects, the model may output information indicating that a length of a configured RLC timer should be modified (such as in accordance with a step size. In some aspects, the model may be trained and used at the RLC receiver. In some aspects, the model may be trained externally to the RLC receiver, and may be provided to the RLC receiver for use. 
     As indicated above,  FIG.  13    is provided as an example. Other examples may differ from what is described with regard to  FIG.  13   . 
       FIG.  14    is a diagram illustrating an example  1400  of training and using a machine learning model in connection with determining whether or how to modify an RLC timer length, in accordance with the present disclosure. The machine learning model training and usage described herein may be performed using a machine learning system. The machine learning system may include or may be included in a computing device, a server, a cloud computing environment, or the like. 
     As shown by reference number  1405 , a machine learning model may be trained using a set of observations. The set of observations may be obtained from training data (e.g., historical data), such as data gathered during one or more processes described herein. In some implementations, the machine learning system may receive the set of observations (e.g., as input) from the computing system, as described elsewhere herein. 
     As shown by reference number  1410 , the set of observations includes a feature set. The feature set may include a set of variables (sometimes referred to herein as parameters), and a variable may be referred to as a feature. A specific observation may include a set of variable values (or feature values) corresponding to the set of variables. In some implementations, the machine learning system may determine variables for a set of observations and/or variable values for a specific observation based on input received from computing system. For example, the machine learning system may identify a feature set (e.g., one or more features and/or feature values) by extracting the feature set from structured data, and/or by receiving input from an operator. 
     As an example, a feature set for a set of observations may include for example, a length of a configured RLC timer, a length of a configured PDCP timer, an RLC retransmitted PDU count, an RLC PDU drop count, a rate of PDCP PDU loss, downlink HARQ failure information for each carrier, a downlink HARQ recovery timeline for each carrier, a downlink BLER for each carrier, a downlink throughput of each carrier, an inter-carrier RLC SN scheduling delay among carriers, or information indicating one or more carriers that are lagging carriers. 
     As shown by reference number  1415 , the set of observations may be associated with a target variable. The target variable may represent a variable having a numeric value, may represent a variable having a numeric value that falls within a range of values or has some discrete possible values, may represent a variable that is selectable from one of multiple options (e.g., one of multiples classes, classifications, or labels) and/or may represent a variable having a Boolean value. A target variable may be associated with a target variable value, and a target variable value may be specific to an observation. In example  1400 , the target variable is a modification of an RLC timer or an indication to modify an RLC timer. 
     The target variable may represent a value that a machine learning model is being trained to predict, and the feature set may represent the variables that are input to a trained machine learning model to predict a value for the target variable. The set of observations may include target variable values so that the machine learning model can be trained to recognize patterns in the feature set that lead to a target variable value. A machine learning model that is trained to predict a target variable value may be referred to as a supervised learning model. 
     In some implementations, the machine learning model may be trained on a set of observations that do not include a target variable. This may be referred to as an unsupervised learning model. In this case, the machine learning model may learn patterns from the set of observations without labeling or supervision, and may provide output that indicates such patterns, such as by using clustering and/or association to identify related groups of items within the set of observations. 
     As shown by reference number  1420 , the machine learning system may train a machine learning model using the set of observations and using one or more machine learning algorithms, such as a regression algorithm, a decision tree algorithm, a neural network algorithm, a k-nearest neighbor algorithm, a support vector machine algorithm, or the like. After training, the machine learning system may store the machine learning model as a trained machine learning model  1425  to be used to analyze new observations. 
     As shown by reference number  1430 , the machine learning system may apply the trained machine learning model  1425  to a new observation, such as by receiving a new observation and inputting the new observation to the trained machine learning model  1425 . The machine learning system may apply the trained machine learning model  1425  to the new observation to generate an output (e.g., a result). The type of output may depend on the type of machine learning model and/or the type of machine learning task being performed. For example, the output may include a predicted value of a target variable, such as when supervised learning is employed. Additionally, or alternatively, the output may include information that identifies a cluster to which the new observation belongs and/or information that indicates a degree of similarity between the new observation and one or more other observations, such as when unsupervised learning is employed. 
     As an example, the trained machine learning model  1425  may predict a value for the target variable, as shown by reference number  1435 . Based on this prediction, the machine learning system may provide a first recommendation, may provide output for determination of a first recommendation, may perform a first automated action, and/or may cause a first automated action to be performed (e.g., by instructing another device to perform the automated action), among other examples. For example, the machine learning model may output a length of a modified RLC timer, or may output an indication to incrementally lengthen or shorten an RLC timer. 
     In some implementations, the trained machine learning model  1425  may classify (e.g., cluster) the new observation in a cluster, as shown by reference number  1440 . The observations within a cluster may have a threshold degree of similarity. As an example, if the machine learning system classifies the new observation in a first cluster, then the machine learning system may provide a first recommendation. Additionally, or alternatively, the machine learning system may perform a first automated action and/or may cause a first automated action to be performed (e.g., by instructing another device to perform the automated action) based on classifying the new observation in the first cluster. 
     In some implementations, the recommendation and/or the automated action associated with the new observation may be based on a target variable value having a particular label (e.g., classification or categorization), may be based on whether a target variable value satisfies one or more threshold (e.g., whether the target variable value is greater than a threshold, is less than a threshold, is equal to a threshold, falls within a range of threshold values, or the like), and/or may be based on a cluster in which the new observation is classified. 
     As indicated above,  FIG.  14    is provided as an example. Other examples may differ from what is described in connection with  FIG.  14   . 
       FIG.  15    is a diagram illustrating an example of RLC status reporting based at least in part on a HARQ recovery delay associated with a carrier, in accordance with the present disclosure.  FIG.  15    is an example of selectively reducing a reassembly timer based at least in part of respective HARQ recovery delays associated with a set of carriers.  FIG.  15    includes a carrier CC0 and a carrier CC1. A length of a configured reassembly timer is shown by reference number  1510 . In  FIG.  15   , RLC SNs 0-9, 21-39, and 61-99 of CC1 are missed. If the RLC receiver started the configured reassembly timer after detecting that RLC SNs 1-9 were missed (that is, after successfully receiving RLC SNs 10-20), then the RLC receiver may wait until an end of the reassembly timer to transmit an RLC status report regarding each RLC hole experienced up until the RLC status report is transmitted. However, waiting for the length of the reassembly timer (which may be configured conservatively according to the parameters of CC0 and CC1) may delay the recovery of the RLC holes associated with RLC SNs 0-9, 21-39, and 61-99 of CC1. 
     Techniques described herein provide per-carrier determination of a reassembly timer such that delay associated with recovery of RLC holes is reduced. For example, the RLC receiver may determine a reassembly timer for a given carrier based at least in part on a HARQ recovery delay associated with the given carrier. The HARQ recovery delay may correspond to a length of time before a HARQ timeout occurs. For example, if the HARQ recovery delay for a given RLC hole has elapsed, the RLC receiver can determine that HARQ has either succeeded or failed for the given RLC hole. Examples of HARQ recovery delays are shown by “HARQ1” (corresponding to RLC SNs 0-9), “HARQ3” (corresponding to RLC SNs 21-39), and “HARQ5” (corresponding to RLC SNs 61-99). “HARQ2” (not shown) may correspond to RLC SNs 10-20, and may be moot since RLC SNs 10-20 were successfully received. “HARQ4” (not shown) may correspond to RLC SNs 40-60, and may be moot since RLC SNs 40-60 were successfully received. 
     The RLC receiver may use a reassembly timer that is based at least in part on the HARQ recovery delay associated with a given carrier. In some aspects, the reassembly timer may be equal to an average HARQ recovery delay associated with a given carrier. In some aspects, the reassembly timer may be configured such that the RLC status report for an RLC hole is transmitted at an end of a HARQ recovery delay associated with a given carrier on which the RLC hole is observed. In some aspects, the RLC receiver may identify the given carrier on which the RLC hole is observed by querying (e.g., querying the physical layer) whether a HARQ procedure is ongoing on the given carrier. In some aspects, the RLC receiver may identify the given carrier on which the RLC hole is observed using techniques described elsewhere herein, such as in connection with  FIGS.  7 A- 10   . 
     As shown by reference number  1520 , the RLC receiver may transmit a first RLC status report in accordance with a modified reassembly timer. For example, the RLC receiver may transmit the first RLC status report after HARQ1 (corresponding to the RLC hole for RLC SNs 0-9) has elapsed. As shown, the first RLC status report may indicate a NACK up to RLC SN 20, meaning that the first RLC status report may indicate that a most recent successfully received RLC SN is RLC SN 20 and that RLC SNs 0-9 were not successfully received. As shown by reference number  1530 , the RLC receiver may transmit a second RLC status report in accordance with the modified reassembly timer. For example, the RLC receiver may transmit the second RLC status report after HARQ3 (corresponding to the RLC hole for RLC SNs 21-39) has elapsed. As shown, the second RLC status report may indicate a NACK up to RLC SN 60, meaning that the first RLC status report may indicate that a most recent successfully received RLC SN is RLC SN 60 and that RLC SNs 21-39 (that is, missed RLC SNs after a most recently acknowledged RLC SN) were not successfully received. After HARQ5 has elapsed, the UE  120  may update the status report to include NACKs for any unreceived RLC SNs, and an ACK for RLC SNs 100-200. 
     As indicated above,  FIG.  15    is provided as an example. Other examples may differ from what is described with regard to  FIG.  15   . 
       FIG.  16    is a diagram illustrating an example  1600  of transmitting a transport block with a poll bit on two or more numerologies, in accordance with the present disclosure. Example  1600  illustrates a state diagram for selecting an uplink path. Example  1600  relates to a case where the UE  120  is an RLC transmitter and the BS  110  is an RLC receiver on the uplink. While  FIG.  16    is primarily described with regard to a first numerology and a second numerology, the techniques described with regard to  FIG.  16    can be applied for multiple configurations, which are described in more detail elsewhere herein. Example  1600  describes how to retransmit a communication, such as a transport block with a poll bit, on multiple numerologies. For example, when a poll request is triggered by a higher layer of the UE  120  (such as an RLC layer), the UE  120  may replicate the poll request on an uplink transport block of each active numerology. Thus, the UE  120  may improve the likelihood of the base station successfully receiving the poll request. 
     In some scenarios, an RLC retransmission (e.g., a PDU, a transport block) on a given uplink grant may fail. More generally, a communication on the given uplink grant may fail. The communication may be associated with a numerology referred to as a preferred numerology. A preferred numerology is a numerology in which an communication was originally to be performed. A preferred carrier is a carrier associated with the preferred numerology on which the communication was originally to be performed. In some cases, the UE  120  may prefer to retransmit the communication using the preferred numerology. In some aspects, the UE  120  may select a numerology as the preferred numerology, for example, based at least in part on the numerology having a lower block error rate than another numerology, a lower latency than another numerology, or the like. 
     Failure of an RLC retransmission may lead to downlink throughput loss. Waiting for a next uplink grant associated with the same numerology as the failed communication (e.g., the preferred numerology for the RLC retransmission) to perform retransmission may increase latency associated with the retransmission. In particular, if the BS  110  stops granting on CCs associated with the preferred numerology for a length of time, the latency may be indefinite. In some aspects, the UE  120  may allow a maximum delay of t after a retransmission is prepared, to wait for a grant on the preferred numerology associated with the retransmission. If the UE  120  does not receive the grant on the preferred numerology associated with the retransmission within t, then the UE  120  may transmit the retransmission on a next available uplink grant irrespective of numerology. This may be particularly beneficial when the FR2 block error rate is not worse than the FR1 block error rate. For example, with  16  HARQ processes, the round-trip time may be 8 ms for a 30 kHz subcarrier spacing and 2 ms for a 120 kHz subcarrier spacing, so waiting for a number of slots on FR2 may not significantly impact latency. In some aspects, the UE  120  may transmit an RLC retransmission on a first available uplink grant irrespective of the numerology associated with the first available uplink grant, and may transmit another RLC retransmission on an uplink grant associated with the preferred numerology of the RLC retransmission if the UE  120  does not receive an acknowledgment associated with the first available uplink grant. In this way, the UE  120  may provide for fast retransmission of a PDU on a first available numerology and subsequent retransmission on another numerology, which may reduce latency associated with retransmission when a preferred numerology is not immediately available for retransmission. 
     In some aspects, a UE  120  may select a numerology on which to transmit an RLC PDU (e.g., a transport block) with a poll bit. The state machine of example  1600  is an example of how to select a numerology in such a case. As shown by reference number  1605 , the UE  120  may wait for a next poll trigger. As shown by reference number  1610 , if the UE  120  detects a poll trigger (e.g., a pollPDU parameter being satisfied, a pollBytes parameter being satisfied, or a t-PollRetransmit timer expiring), the UE  120  may wait for an uplink grant. As shown by reference number  1615 , if the UE  120  receives an FR2 grant, the UE  120  may transmit the PDU on FR2. As shown by reference number  1620 , if the UE  120  transmits a PDU on FR2, and the UE  120  has already transmitted a PDU on FR1, the UE  120  may wait for a next poll trigger. Similarly, if the UE  120  transmits a PDU on FR1 and has already transmitted a PDU on FR2, the UE  120  may wait for a next poll trigger. As shown by reference number  1625 , if the uplink grant is an FR1 grant, the UE  120  may transmit the PDU on FR1. Additionally, as shown by reference number  1630 , if the UE  120  receives an FR1 grant after an FR2 grant, the UE  120  may transmit the PDU on FR1. As shown by reference number  1635 , if the UE  120  receives an FR2 grant after an FR1 grant, the UE  120  may transmit the PDU on FR2. Thus, the UE  120  may make a note of a TB&#39;s numerology when a first poll PDU is sent. Upon receiving a grant on another numerology, the UE  120  may retransmit the PDU for the TB, thereby leveraging the fast polling framework. Thus, the UE  120  may transmit a transport block using a first numerology and a second numerology, which increases the likelihood of the base station  110  receiving the poll, since even if an uplink transmission on any one numerology fails due to a bad channel, the base station  110  can still receive the poll request from the transport block on another numerology. 
     In some aspects, the UE  120  may select an uplink path for a MAC communication. For example, a BS  110  may configure a physical uplink control channel scheduling request (PUCCH-SR) on a primary CC and a secondary CC, where the primary CC is a cell with a PUCCH-SR configured in a primary PUCCH group and the secondary CC is a cell with a PUCCH-SR configured in a secondary PUCCH group. The UE  120  may use an earliest SR occasion, of SR occasions on the primary CC and the secondary CC, to transmit an SR. Thus, the UE  120  may reduce delay from uplink data arrival to SR transmission. For example, if transmission of an SR on one CC fails, the UE  120  may transmit the SR on an earliest SR occasion on a second CC, hereby improving latency. 
     In some aspects, the primary CC and the secondary CC may have different numerologies and/or may be part of different connected-mode discontinuous reception (cDRX) groups. If at least one of the SR resources used to transmit the SR is associated with a sub6 numerology, then the likelihood of SR success is increased, as sub6 uplink transmissions tend to be more robust than mmW uplink transmissions. Furthermore, if the primary CC and the secondary CC are in different cDRX groups, then it is more likely that at least one CC is in a DRX ON period when the uplink data arrives. Thus, the UE  120  can skip delay associated with awakening outside of the DRX ON period. Furthermore, in some aspects, the BS  110  may configure a prescheduled grant for the SR, which eliminates a wait time for a next SR occasion and which reduces delay between the SR and a transmission of the data by the UE  120 . 
     In some aspects, the UE  120  may transmit a buffer status report (BSR) or a power headroom report (PHR). A PHR indicates an amount of additional transmit power that the UE  120  can provide. A BSR indicates an amount of data buffered for the UE  120 . For example, the UE  120  may transmit the BSR or PHR via a carrier associated with an FR1 numerology and a carrier associated with an FR2 numerology, which improves the likelihood of successful decoding of the BSR or PHR. In some aspects, the UE  120  may transmit the BSR or PHR on a first carrier associated with a first numerology at a time to. The UE  120  may receive a grant on a second carrier associated with a second numerology for a transmission at a time t 1 . The UE  120  may retransmit the BSR or PHR at the time t 1 . In some aspects, the UE  120  may merge the BSR with any new BSR triggered between t 0  and t 1 . Retransmitting the BSR or PHR at t 0  and t 1  may provide an increased number of sampling points to the base station  110 . In some aspects, the UE  120  may skip retransmission of the PHR or the BSR based at least in part on a HARQ block error rate (BLER). For example, if the HARQ BLER satisfies a threshold, the UE  120  may skip retransmission of the PHR or BSR after a transmission. 
       FIG.  17    is a diagram illustrating an example  1700  of signaling associated with TB generation based at least in part on a Voice over NR (VoNR) call in FR2, in accordance with the present disclosure. As shown,  FIG.  17    includes a UE  120  and a BS  110 . 
     As shown by reference number  1710 , the UE  120  may transmit capability information to the BS  110 . The capability information may indicate that the BS  110  is to avoid VoNR in FR2. For example, the capability information may include a voiceOverNR parameter that indicates to use logical channel prioritization (LCP) restriction to ensure that VoNR data is communicated in FR1. If the BS  110  adheres to the capability information, then the UE  120  may pack FR2 TBs with data only. However, in some cases, as shown by reference number  1720 , the BS  110  may allow the VoNR data to be communicated in FR2. As shown by reference number  1730 , the UE  120  may pack an uplink TB for FR2 with as much data as is available. If the uplink TB is not fully packed (e.g., filled), then in some aspects, the UE  120  may include a non-zero padding BSR (to account for voice data) and may pad (e.g., fill) the rest of the uplink TB, as shown by reference number  1740 . If the UE  120  includes the non-zero padding BSR and pads the uplink TB, then the UE  120  may transmit a voice packet including the uplink TB on a next available grant in FR1, as shown by reference number  1750   
     In some other aspects, the UE  120  may pack the remainder of the TB with the voice packet, and may maintain a copy of the voice packet to transmit on a next FR1 grant, as shown by reference number  1760 . The UE  120  may note an RLC SN from acknowledged mode (AM) data radio bearers (DRBs) transmitted on the uplink TB. If an RLC ACK is received for the RLC SN before a next FR1 grant, the UE  120  may determine not to transmit the voice packet on the next FR1 grant. In some aspects, the UE  120  may track HARQ success for the uplink TB in FR2, and may skip duplication of the uplink TB based at least in part on whether HARQ indicates successful transmission of the uplink TB. As shown by reference number  1770 , the UE  120  may transmit the uplink TB and/or one or more retransmissions of the voice packet. 
     As indicated above,  FIG.  17    is provided as an example. Other examples may differ from what is described with regard to  FIG.  17   . 
       FIG.  18    is a diagram illustrating an example  1800  of an O-RAN architecture, in accordance with the present disclosure. As shown in  FIG.  18   , the O-RAN architecture may include a control unit (CU)  1810  that communicates with a core network  1820  via a backhaul link. Furthermore, the CU  1810  may communicate with one or more DUs  1830  via respective midhaul links. The DUs  1830  may each communicate with one or more RUs  1840  via respective fronthaul links, and the RUs  1840  may each communicate with respective UEs  120  via radio frequency (RF) access links. The DUs  1830  and the RUs  1840  may also be referred to as O-RAN DUs (O-DUs)  1830  and O-RAN RUs (O-RUs)  1840 , respectively. 
     In some aspects, the DUs  1830  and the RUs  1840  may be implemented according to a functional split architecture in which functionality of a base station  110  (e.g., an eNB or a gNB) is provided by a DU  1830  and one or more RUs  1840  that communicate over a fronthaul link. Accordingly, as described herein, a base station  1810  may include a DU  1830  and one or more RUs  1840  that may be co-located or geographically distributed. In some aspects, the DU  1830  and the associated RU(s)  1840  may communicate via a fronthaul link to exchange real-time control plane information via a lower layer split (LLS) control plane (LLS-C) interface, to exchange non-real-time management information via an LLS management plane (LLS-M) interface, and/or to exchange user plane information via an LLS user plane (LLS-U) interface. 
     Accordingly, the DU  1830  may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs  1840 . For example, in some aspects, the DU  1830  may host a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (e.g., forward error correction (FEC) encoding and decoding, scrambling, and/or modulation and demodulation) based at least in part on a lower layer functional split. Higher layer control functions, such as a packet data convergence protocol (PDCP), radio resource control (RRC), and/or service data adaptation protocol (SDAP), may be hosted by the CU  1810 . The RU(s)  1840  controlled by a DU  1830  may correspond to logical nodes that host RF processing functions and low-PHY layer functions (e.g., fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, and/or physical random access channel (PRACH) extraction and filtering) based at least in part on the lower layer functional split. Accordingly, in an O-RAN architecture, the RU(s)  1840  handle all over the air (OTA) communication with a UE  1820 , and real-time and non-real-time aspects of control and user plane communication with the RU(s)  1840  are controlled by the corresponding DU  1830 , which enables the DU(s)  1830  and the CU  1810  to be implemented in a cloud-based RAN architecture. The techniques described with regard to  FIGS.  1 - 24    can be applied in an O-RAN architecture. 
     As indicated above,  FIG.  18    is provided as an example. Other examples may differ from what is described with regard to  FIG.  18   . 
       FIG.  19    is a diagram illustrating an example process  1900  performed, for example, by a UE, in accordance with the present disclosure. Example process  1900  is an example where the UE (e.g., UE  120 ) performs operations associated with carrier aggregation for mixed frequency ranges. For example,  FIG.  19    depicts operations of an RLC receiver, and these operations can be applied for any RLC receiver. 
     As shown in  FIG.  19   , in some aspects, process  1900  may include communicating on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters (block  1910 ). For example, the UE (e.g., using communication manager  140  and/or reception component  2202 , depicted in  FIG.  22   ) may communicate on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters, as described above. 
     As further shown in  FIG.  19   , in some aspects, process  1900  may include detecting a radio link control (RLC) discontinuity on at least one set of carriers, of the first set of carriers or the second set of carriers (block  1920 ). For example, the UE (e.g., using communication manager  140  and/or detection component  2208 , depicted in  FIG.  22   ) may detect a radio link control (RLC) discontinuity on at least one set of carriers, of the first set of carriers or the second set of carriers, as described above. 
     As further shown in  FIG.  19   , in some aspects, process  1900  may include transmitting an RLC status report in accordance with an RLC timer that is based at least in part on at least one of a first hybrid automatic repeat request (HARQ) parameter associated with the first set of parameters or a second HARQ parameter associated with the second set of parameters, wherein the RLC timer based at least in part on a number of RLC duplicates received by the UE (block  1930 ). For example, the UE (e.g., using communication manager  140  and/or transmission component  2204 , depicted in  FIG.  2   ) may transmit an RLC status report in accordance with an RLC timer that is based at least in part on at least one of a first hybrid automatic repeat request (HARQ) parameter associated with the first set of parameters or a second HARQ parameter associated with the second set of parameters, wherein the RLC timer based at least in part on a number of RLC duplicates received by the UE, as described above. 
     Process  1900  may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein. 
     In a first aspect, the first set of parameters is associated with a first numerology and the second set of parameters is associated with a second numerology. 
     In a second aspect, alone or in combination with the first aspect, process  1900  includes identifying one or more numerologies, of the first numerology or the second numerology, in which the RLC discontinuity occurred, wherein the RLC timer is determined in accordance with a numerology of the identified one or more numerologies. 
     In a third aspect, alone or in combination with one or more of the first and second aspects, identifying the one or more numerologies is based at least in part on a HARQ transmission associated with a slot associated with the RLC discontinuity and a cyclic redundancy check (CRC) error associated with the slot associated with the RLC discontinuity. 
     In a fourth aspect, alone or in combination with one or more of the first through third aspects, identifying the one or more numerologies is based at least in part on one or more estimated transport block sizes associated with the RLC discontinuity and an amount of RLC bytes received in a slot associated with the RLC discontinuity. 
     In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the one or more estimated transport block sizes include a first estimated transport block size associated with the first numerology and a second estimated transport block size associated with the second numerology. 
     In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, transmitting the RLC status report is based at least in part on receiving a poll protocol data unit associated with the identified one or more numerologies or determining that a reassembly timer for the identified one or more numerologies has expired, and wherein the identified one or more numerologies include a single numerology. 
     In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the identified one or more numerologies include only the first numerology, and wherein transmitting the RLC status report based at least in part on the identified one or more FRs further comprises transmitting, based at least in part on a poll protocol data unit or expiration of the RLC timer, a negative acknowledgment regarding the RLC discontinuity. 
     In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, the identified one or more numerologies include only the first numerology and the RLC timer is a configured RLC timer associated with the first numerology. 
     In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, the identified one or more numerologies include the first numerology and the second numerology, and wherein the RLC timer is determined as a longer RLC timer, of an RLC timer associated with the first numerology and an RLC timer associated with the second numerology. 
     In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, the RLC timer is based at least in part on a HARQ parameter associated with a carrier, of the first set of carriers or the second set of carriers, on which the RLC discontinuity is detected. 
     In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, the HARQ parameter is at least one of a HARQ round trip time or a HARQ recovery delay. 
     In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, the RLC timer is based at least in part on a combination of the first HARQ parameter and the second HARQ parameter, and based at least in part on a first numerology associated with the first set of carriers and a second numerology associated with the second set of carriers. 
     In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, the RLC discontinuity is an RLC discontinuity on a first carrier of the first set of carriers and a second carrier of the second set of carriers, and wherein the RLC timer is determined in accordance with a lower numerology of a first numerology of the first set of carriers and a second numerology of the second set of carriers. 
     In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, the RLC status report indicates an RLC status up to a most recent RLC discontinuity. 
     In a fifteenth aspect, alone or in combination with one or more of the first through fourteenth aspects, detecting the RLC discontinuity further comprises detecting a plurality of RLC discontinuities, and wherein transmitting the RLC status report further comprises transmitting the RLC status report indicating an RLC status for all RLC discontinuities, of the plurality of RLC discontinuities and associated with the second set of carriers, up to a next RLC discontinuity of the first set of carriers, wherein the second set of carriers is associated with a second numerology that is higher than a first numerology of the first set of carriers. 
     In a sixteenth aspect, alone or in combination with one or more of the first through fifteenth aspects, detecting the RLC discontinuity further comprises detecting a plurality of RLC discontinuities, and wherein transmitting the RLC status report further comprises transmitting the RLC status report indicating an RLC status for all RLC discontinuities, of the plurality of RLC discontinuities, for which the UE estimates that HARQ recovery is complete. 
     In a seventeenth aspect, alone or in combination with one or more of the first through sixteenth aspects, process  1900  includes maintaining, for the first set of parameters and the second set of parameters, separate RLC sequence number tracking. 
     In an eighteenth aspect, alone or in combination with one or more of the first through seventeenth aspects, process  1900  includes maintaining, for the first set of parameters and the second set of parameters, a separate set of RLC timers. 
     In a nineteenth aspect, alone or in combination with one or more of the first through eighteenth aspects, the RLC discontinuity is associated with only the second set of carriers, and wherein the RLC status report indicates an RLC status of one or more RLC protocol data units on the second set of carriers after an unacknowledged RLC discontinuity on the first set of carriers. 
     In a twentieth aspect, alone or in combination with one or more of the first through nineteenth aspects, an acknowledgment sequence number of the RLC status is set to a most recently received sequence number on the second set of carriers. 
     In a twenty-first aspect, alone or in combination with one or more of the first through twentieth aspects, the first set of parameters or the second set of parameters indicates at least one of a duplexing configuration, a scheduling delay, a numerology, a frequency range, or an uplink/downlink slot allocation. 
     In a twenty-second aspect, alone or in combination with one or more of the first through twenty-first aspects, the first HARQ parameter or the second HARQ parameter includes at least one of a HARQ round-trip time, or a HARQ recovery delay. 
     In a twenty-third aspect, alone or in combination with one or more of the first through twenty-second aspects, detecting the RLC discontinuity further comprises detecting that a threshold number of retransmitted RLC protocol data units are dropped and that a number of HARQ failures is lower than a threshold. 
     In a twenty-fourth aspect, alone or in combination with one or more of the first through twenty-third aspects, detecting the RLC discontinuity further comprises detecting that a sum of an inter-carrier sequence number delay between the first set of carriers and the second set of carriers, and the HARQ parameter, is greater than a configured value of the RLC timer. 
     In a twenty-fifth aspect, alone or in combination with one or more of the first through twenty-fourth aspects, process  1900  includes determining the RLC timer. 
     In a twenty-sixth aspect, alone or in combination with one or more of the first through twenty-fifth aspects, the RLC timer is equal in length to a HARQ recovery delay indicated by the HARQ parameter. 
     In a twenty-seventh aspect, alone or in combination with one or more of the first through twenty-sixth aspects, determining the RLC timer is based at least in part on a model trained using machine learning. 
     In a twenty-eighth aspect, alone or in combination with one or more of the first through twenty-seventh aspects, the number of RLC duplicates received by the UE is based at least in part on a successful HARQ transmission following transmission of one or more negative acknowledgments. 
     Although  FIG.  19    shows example blocks of process  1900 , in some aspects, process  1900  may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in  FIG.  19   . Additionally, or alternatively, two or more of the blocks of process  1900  may be performed in parallel. 
       FIG.  20    is a diagram illustrating an example process  2000  performed, for example, by an UE, in accordance with the present disclosure. Example process  2000  is an example where the UE (e.g., UE  120 ) performs operations associated with carrier aggregation for mixed frequency ranges. For example,  FIG.  20    depicts operations of an RLC transmitter, and these operations can be applied for any RLC transmitter. 
     As shown in  FIG.  20   , in some aspects, process  2000  may include transmitting a communication on one of a first set of carriers in a first frequency range (FR) or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology (block  2010 ). For example, the UE (e.g., using communication manager  140  and/or transmission component  2204 , depicted in  FIG.  22   ) may transmit a communication on one of a first set of carriers in a first frequency range (FR) or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology, as described above. 
     As further shown in  FIG.  20   , in some aspects, process  2000  may include receiving a radio link control (RLC) status report indicating an RLC discontinuity associated with the communication (block  2020 ). For example, the UE (e.g., using communication manager  140  and/or reception component  2202 , depicted in  FIG.  22   ) may receive a radio link control (RLC) status report indicating an RLC discontinuity associated with the communication, as described above. 
     As further shown in  FIG.  20   , in some aspects, process  2000  may include performing a retransmission of the communication on a preferred carrier associated with the preferred numerology in response to an uplink grant on the preferred carrier being received within a length of time (block  2030 ). For example, the UE (e.g., using communication manager  140  and/or transmission component  2204 , depicted in  FIG.  22   ) may perform a retransmission of the communication on a preferred carrier associated with the preferred numerology in response to an uplink grant on the preferred carrier being received within a length of time, as described above. 
     As further shown in  FIG.  20   , in some aspects, process  2000  may include performing the retransmission of the communication on a first available uplink grant when no uplink grant on the preferred carrier is received within the length of time (block  2030 ). For example, the UE (e.g., using communication manager  140  and/or transmission component  2204 , depicted in  FIG.  22   ) may perform the retransmission of the communication on a first available uplink grant when no uplink grant on the preferred carrier is received within the length of time, as described above. 
     Process  2000  may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein. 
     In a first aspect, the retransmission is on the first available uplink grant of the preferred numerology and the method further comprises retransmitting the retransmission on a carrier associated with another numerology if no acknowledgment of the retransmission has been received after performing the retransmission. 
     In a second aspect, alone or in combination with the first aspect, process  2000  includes transmitting a buffer status report and a power headroom report on a carrier of the first set of carriers, and transmitting the buffer status report and the power headroom report on a carrier of the second set of carriers. 
     In a third aspect, alone or in combination with one or more of the first and second aspects, the buffer status report as transmitted on the carrier of the second set of carriers is updated relative to the buffer status report as transmitted on the carrier of the first set of carriers. 
     In a fourth aspect, alone or in combination with one or more of the first through third aspects, the buffer status report as transmitted on the carrier of the second set of carriers is merged with another buffer status report triggered after transmission of the buffer status report on the carrier of the first set of carriers. 
     In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the communication is an RLC protocol data unit carrying a poll bit. 
     Although  FIG.  20    shows example blocks of process  2000 , in some aspects, process  2000  may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in  FIG.  20   . Additionally, or alternatively, two or more of the blocks of process  2000  may be performed in parallel. 
       FIG.  21    is a diagram illustrating an example process  2100  performed, for example, by a UE, in accordance with the present disclosure. Example process  2100  is an example where the UE (e.g., UE  120 ) performs operations associated with carrier aggregation for mixed frequency ranges. 
     As shown in  FIG.  21   , in some aspects, process  2100  may include transmitting an indication to avoid Voice over New Radio (VoNR) communication in a first frequency range (block  2110 ). For example, the UE (e.g., using communication manager  140  and/or transmission component  2204 , depicted in  FIG.  22   ) may transmit an indication to avoid Voice over New Radio (VoNR) communication in a first frequency range, as described above. In some aspects, the first frequency range is FR2. 
     As further shown in  FIG.  21   , in some aspects, process  2100  may include generating a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet (block  2120 ). For example, the UE (e.g., using communication manager  140  and/or generation component  2212 , depicted in  FIG.  22   ) may generate a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet, as described above. 
     As further shown in  FIG.  21   , in some aspects, process  2100  may include transmitting the first TB in the first frequency range (block  2130 ). For example, the UE (e.g., using communication manager  140  and/or transmission component  2204 , depicted in  FIG.  22   ) may transmit the first TB in the first frequency range, as described above. 
     As further shown in  FIG.  21   , in some aspects, process  2100  may optionally include transmitting a second TB associated with the VoNR communication in a second frequency range based at least in part on whether the first TB includes the non-zero padding buffer status report or the voice packet (block  2140 ). For example, the UE (e.g., using communication manager  140  and/or transmission component  2204 , depicted in  FIG.  22   ) may transmit a second TB associated with the VoNR communication in a second frequency range if the first TB includes the voice packet, as described above. In some aspects, the second frequency range is FR1. 
     Process  2100  may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein. 
     In a first aspect, process  2100  includes transmitting the voice packet in the second TB. 
     In a second aspect, alone or in combination with the first aspect, transmitting the voice packet in the second TB is based at least in part on not having received an acknowledgment of the first TB. 
     Although  FIG.  21    shows example blocks of process  2100 , in some aspects, process  2100  may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in  FIG.  21   . Additionally, or alternatively, two or more of the blocks of process  2100  may be performed in parallel. 
       FIG.  22    is a diagram of an example apparatus  2200  for wireless communication, in accordance with the present disclosure. The apparatus  2200  may be a UE, or a UE may include the apparatus  2200 . In some aspects, the apparatus  2200  includes a reception component  2202  and a transmission component  2204 , which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus  2200  may communicate with another apparatus  2206  (such as a UE, a base station, or another wireless communication device) using the reception component  2202  and the transmission component  2204 . As further shown, the apparatus  2200  may include the communication manager  140 . The communication manager  140  may include one or more of a detection component  2208 , an identification component  2210 , or a generation component  2212 , among other examples. 
     In some aspects, the apparatus  2200  may be configured to perform one or more operations described herein in connection with  FIGS.  3 - 18   . Additionally, or alternatively, the apparatus  2200  may be configured to perform one or more processes described herein, such as process  1900  of  FIG.  19   , process  2000  of  FIG.  20   , process  2100  of  FIG.  21   , or a combination thereof. In some aspects, the apparatus  2200  and/or one or more components shown in  FIG.  22    may include one or more components of the UE described in connection with  FIG.  2   . Additionally, or alternatively, one or more components shown in  FIG.  22    may be implemented within one or more components described in connection with  FIG.  2   . Additionally, or alternatively, one or more components of the set of components may be implemented at least in part as software stored in a memory. For example, a component (or a portion of a component) may 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 the component. 
     The reception component  2202  may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus  2206 . The reception component  2202  may provide received communications to one or more other components of the apparatus  2200 . In some aspects, the reception component  2202  may 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 may provide the processed signals to the one or more other components of the apparatus  2200 . In some aspects, the reception component  2202  may include one or more antennas, a modem, a demodulator, a MIMO detector, a receive processor, a controller/processor, a memory, or a combination thereof, of the UE described in connection with  FIG.  2   . 
     The transmission component  2204  may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus  2206 . In some aspects, one or more other components of the apparatus  2200  may generate communications and may provide the generated communications to the transmission component  2204  for transmission to the apparatus  2206 . In some aspects, the transmission component  2204  may 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 may transmit the processed signals to the apparatus  2206 . In some aspects, the transmission component  2204  may include one or more antennas, a modem, a modulator, a transmit MIMO processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the UE described in connection with  FIG.  2   . In some aspects, the transmission component  2204  may be co-located with the reception component  2202  in a transceiver. 
     The transmission component  2204  may communicate on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters. The detection component  2208  may detect a radio link control (RLC) discontinuity on at least one set of carriers, of the first set of carriers or the second set of carriers. The identification component  2210  may identify one or more FRs, of the first FR and the second FR, in which the RLC discontinuity occurred. The transmission component  2204  may transmitting an RLC status report in accordance with an RLC timer. 
     The transmission component  2204  may transmit a communication on one of a first set of carriers in a first frequency range (FR) or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology. The reception component  2202  may receive a radio link control (RLC) status report indicating an RLC discontinuity associated with the communication. The transmission component  2204  may perform a retransmission of the communication of the communication on a preferred carrier associated with the preferred numerology in response to an uplink grant on the preferred carrier being received within a length of time. The transmission component  2204  may perform the retransmission of the communication on a first available uplink grant when no uplink grant on the preferred carrier is received within the length of time. 
     The transmission component  2204  may transmit an indication to avoid VoNR communication in a first frequency range. The generation component  2212  may generating a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet. The transmission component  2204  may transmit the first TB in the first frequency range. The transmission component  2204  may transmit a second TB associated with the VoNR communication in a second frequency range based at least in part on the first TB including the non-zero padding buffer status report or the voice packet. 
     The number and arrangement of components shown in  FIG.  22    are provided as an example. In practice, there may be additional components, fewer components, different components, or differently arranged components than those shown in  FIG.  22   . Furthermore, two or more components shown in  FIG.  22    may be implemented within a single component, or a single component shown in  FIG.  22    may be implemented as multiple, distributed components. Additionally, or alternatively, a set of (one or more) components shown in  FIG.  22    may perform one or more functions described as being performed by another set of components shown in  FIG.  22   . 
       FIG.  23    is a diagram illustrating an example  2300  of a hardware implementation for an apparatus  2305  employing a processing system  2310 , in accordance with the present disclosure. The apparatus  2305  may be a UE. 
     The processing system  2310  may be implemented with a bus architecture, represented generally by the bus  2315 . The bus  2315  may include any number of interconnecting buses and bridges depending on the specific application of the processing system  2310  and the overall design constraints. The bus  2315  links together various circuits including one or more processors and/or hardware components, represented by the processor  2320 , the illustrated components, and the computer-readable medium/memory  2325 . The bus  2315  may also link various other circuits, such as timing sources, peripherals, voltage regulators, and/or power management circuits. 
     The processing system  2310  may be coupled to a transceiver  2330 . The transceiver  2330  is coupled to one or more antennas  2335 . The transceiver  2330  provides a means for communicating with various other apparatuses over a transmission medium. The transceiver  2330  receives a signal from the one or more antennas  2335 , extracts information from the received signal, and provides the extracted information to the processing system  2310 , specifically the reception component  1702 . In addition, the transceiver  2330  receives information from the processing system  2310 , specifically the transmission component  1704 , and generates a signal to be applied to the one or more antennas  2335  based at least in part on the received information. 
     The processing system  2310  includes a processor  2320  coupled to a computer-readable medium/memory  2325 . The processor  2320  is responsible for general processing, including the execution of software stored on the computer-readable medium/memory  2325 . The software, when executed by the processor  2320 , causes the processing system  2310  to perform the various functions described herein for any particular apparatus. The computer-readable medium/memory  2325  may also be used for storing data that is manipulated by the processor  2320  when executing software. The processing system further includes at least one of the illustrated components. The components may be software modules running in the processor  2320 , resident/stored in the computer readable medium/memory  2325 , one or more hardware modules coupled to the processor  2320 , or some combination thereof. 
     In some aspects, the processing system  2310  may be a component of the UE  120  and may include the memory  282  and/or at least one of the TX MIMO processor  266 , the RX processor  258 , and/or the controller/processor  280 . In some aspects, the apparatus  2305  for wireless communication includes means for communicating on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters; means for detecting a radio link control (RLC) discontinuity on at least one set of carriers, of the first set of carriers or the second set of carriers; and/or means for transmitting an RLC status report in accordance with an RLC timer that is based at least in part on at least one of a first hybrid automatic repeat request (HARQ) parameter associated with the first set of parameters or a second HARQ parameter associated with the second set of parameters, wherein the RLC timer based at least in part on a number of RLC duplicates received by the UE; means for transmitting a communication on one of a first set of carriers in a first frequency range (FR) or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology; means for receiving a radio link control (RLC) status report indicating an RLC discontinuity associated with the communication; and/or one of: means for performing a retransmission of the communication on a preferred carrier associated with the preferred numerology in response to an uplink grant on the preferred carrier being received within a length of time, or means for performing the retransmission of the communication on a first available uplink grant when no uplink grant on the preferred carrier is received within the length of time; means for transmitting an indication to avoid Voice over New Radio (VoNR) communication in a first frequency range; means for generating a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet; means for transmitting the first TB in the first frequency range; and/or means for transmitting a second TB associated with the VoNR communication in a second frequency range based at least in part on the first TB including the non-zero padding buffer status report or the voice packet. The aforementioned means may be one or more of the aforementioned components of the apparatus  2200  and/or the processing system  2310  of the apparatus  2305  configured to perform the functions recited by the aforementioned means. As described elsewhere herein, the processing system  2310  may include the TX MIMO processor  266 , the RX processor  258 , and/or the controller/processor  280 . In one configuration, the aforementioned means may be the TX MIMO processor  266 , the RX processor  258 , and/or the controller/processor  280  configured to perform the functions and/or operations recited herein. 
       FIG.  23    is provided as an example. Other examples may differ from what is described in connection with  FIG.  23   . 
       FIG.  24    is a diagram illustrating an example  2400  of an implementation of code and circuitry for an apparatus  2402 . The apparatus  2402  may be a UE, such as UE  120   a  among other examples. 
     As further shown in  FIG.  24   , the apparatus may include circuitry for communicating on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters (circuitry  2404 ). For example, the apparatus may include circuitry to enable the apparatus to communicate on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters. 
     As further shown in  FIG.  24   , the apparatus may include circuitry for detecting an RLC discontinuity on at least one set of carriers, of the first set of carriers or the second set of carriers (circuitry  2406 ). For example, the apparatus may include circuitry to enable the apparatus to detect an RLC discontinuity on at least one set of carriers, of the first set of carriers or the second set of carriers. 
     As further shown in  FIG.  24   , the apparatus may include circuitry for identifying one or more FRs, of the first FR and the second FR, in which the RLC discontinuity occurred (circuitry  2408 ). For example, the apparatus may include circuitry to enable the apparatus to identify one or more FRs, of the first FR and the second FR, in which the RLC discontinuity occurred. 
     As further shown in  FIG.  24   , the apparatus may include circuitry for transmitting an RLC status report in accordance with an RLC timer that is based at least in part on at least one of a first hybrid automatic repeat request (HARQ) parameter associated with the first set of parameters or a second HARQ parameter associated with the second set of parameters, wherein the RLC timer is based at least in part on a number of RLC duplicates received by the UE (circuitry  2410 ). For example, the apparatus may include circuitry to enable the apparatus to transmit an RLC status report in accordance with an RLC timer that is based at least in part on at least one of a first hybrid automatic repeat request (HARQ) parameter associated with the first set of parameters or a second HARQ parameter associated with the second set of parameters, wherein the RLC timer is based at least in part on a number of RLC duplicates received by the UE. 
     As further shown in  FIG.  24   , the apparatus may include circuitry for transmitting a communication on one of a first set of carriers in a first frequency range (FR) or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology(circuitry  2412 ). For example, the apparatus may include circuitry to enable the apparatus to transmit a communication on one of a first set of carriers in a first frequency range (FR) or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology. 
     As further shown in  FIG.  24   , the apparatus may include circuitry for receiving an RLC status report indicating an RLC discontinuity associated with the communication (circuitry  2414 ). For example, the apparatus may include circuitry to enable the apparatus to receive an RLC status report indicating an RLC discontinuity associated with the communication. 
     As further shown in  FIG.  24   , the apparatus may include circuitry for performing a retransmission of the communication (circuitry  2416 ). For example, the apparatus may include circuitry to enable the apparatus to perform a retransmission of the communication. 
     As further shown in  FIG.  24   , the apparatus may include circuitry for transmitting an indication to avoid VoNR communication in a first frequency range (circuitry  2418 ). For example, the apparatus may include circuitry to enable the apparatus to transmit an indication to avoid VoNR communication in a first frequency range. 
     As further shown in  FIG.  24   , the apparatus may include circuitry for generating a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet (circuitry  2420 ). For example, the apparatus may include circuitry to enable the apparatus to generate a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet. 
     As further shown in  FIG.  24   , the apparatus may include circuitry for transmitting the first TB in the first frequency range and a second TB in a second frequency range (circuitry  2422 ). For example, the apparatus may include circuitry to transmit the first TB in the first frequency range and a second TB in a second frequency range. 
     As further shown in  FIG.  24   , the apparatus may include, stored in computer-readable medium  2325 , code for communicating on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters (code  2424 ). For example, the apparatus may include code that, when executed by the processor  2320 , may cause the transceiver  2330  to communicate on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters. 
     As further shown in  FIG.  24   , the apparatus may include, stored in computer-readable medium  2325 , code for detecting an RLC discontinuity on at least one of the first set of carriers or the second set of carriers (code  2426 ). For example, the apparatus may include code that, when executed by the processor  2320 , may cause the transceiver  2330  to detect an RLC discontinuity on at least one of the first set of carriers or the second set of carriers. 
     As further shown in  FIG.  24   , the apparatus may include, stored in computer-readable medium  2325 , code for identifying one or more FRs, of the first FR and the second FR, in which the RLC discontinuity occurred (code  2428 ). For example, the apparatus may include code that, when executed by the processor  2320 , may cause the transceiver  2330  to identify one or more FRs, of the first FR and the second FR, in which the RLC discontinuity occurred. 
     As further shown in  FIG.  24   , the apparatus may include, stored in computer-readable medium  2325 , code for transmitting an RLC status report in accordance with an RLC timer that is based at least in part on at least one of a first hybrid automatic repeat request (HARQ) parameter associated with the first set of parameters or a second HARQ parameter associated with the second set of parameters, wherein the RLC timer is based at least in part on a number of RLC duplicates received by the UE (code  2430 ). For example, the apparatus may include code that, when executed by the processor  2320 , may cause the transceiver  2330  to transmit an RLC status report in accordance with an RLC timer that is based at least in part on at least one of a first hybrid automatic repeat request (HARQ) parameter associated with the first set of parameters or a second HARQ parameter associated with the second set of parameters, wherein the RLC timer is based at least in part on a number of RLC duplicates received by the UE. 
     As further shown in  FIG.  24   , the apparatus may include, stored in computer-readable medium  2325 , code for transmitting a communication on one of a first set of carriers in a first frequency range (FR) or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology (code  2432 ). For example, the apparatus may include code that, when executed by the processor  2320 , may cause the transceiver  2330  to transmit a communication on one of a first set of carriers in a first FR or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology. 
     As further shown in  FIG.  24   , the apparatus may include, stored in computer-readable medium  2325 , code for receiving an RLC status report indicating an RLC discontinuity associated with the communication (code  2434 ). For example, the apparatus may include code that, when executed by the processor  2320 , may cause the transceiver  2330  to receive an RLC status report indicating an RLC discontinuity associated with the communication. 
     As further shown in  FIG.  24   , the apparatus may include, stored in computer-readable medium  2325 , code for performing a retransmission of the communication (code  2436 ). For example, the apparatus may include code that, when executed by the processor  2320 , may cause the transceiver  2330  to perform a retransmission of the communication. 
     As further shown in  FIG.  24   , the apparatus may include, stored in computer-readable medium  2325 , code for transmitting an indication to avoid VoNR communication in a first frequency range (code  2438 ). For example, the apparatus may include code that, when executed by the processor  2320 , may cause the transceiver  2330  to transmit an indication to avoid VoNR communication in a first frequency range. 
     As further shown in  FIG.  24   , the apparatus may include, stored in computer-readable medium  2325 , code for generating a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet (code  2440 ). For example, the apparatus may include code that, when executed by the processor  2320 , may cause the transceiver  2330  to generate a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet. 
     As further shown in  FIG.  24   , the apparatus may include, stored in computer-readable medium  2325 , code for transmitting the first TB in the first frequency range and a second TB in a second frequency range (code  2442 ). For example, the apparatus may include code that, when executed by the processor  2320 , may cause the transceiver  2330  to transmit the first TB in the first frequency range and a second TB in a second frequency range. 
       FIG.  24    is provided as an example. Other examples may differ from what is described in connection with  FIG.  24   . 
     The following provides an overview of some Aspects of the present disclosure: 
     Aspect 1: A method of wireless communication performed by a user equipment (UE), comprising: communicating on a first set of carriers associated with a first set of parameters and a second set of carriers associated with a second set of parameters; detecting a radio link control (RLC) discontinuity on at least one set of carriers, of the first set of carriers or the second set of carriers; and transmitting an RLC status report in accordance with an RLC timer that is based at least in part on at least one of a first hybrid automatic repeat request (HARQ) parameter associated with the first set of parameters or a second HARQ parameter associated with the second set of parameters, wherein the RLC timer based at least in part on a number of RLC duplicates received by the UE. 
     Aspect 2: The method of Aspect 1, wherein the first set of parameters is associated with a first numerology and the second set of parameters is associated with a second numerology. 
     Aspect 3: The method of Aspect 2, further comprising: identifying one or more numerologies, of the first numerology or the second numerology, in which the RLC discontinuity occurred, wherein the RLC timer is determined in accordance with a numerology of the identified one or more numerologies. 
     Aspect 4: The method of Aspect 3, wherein identifying the one or more numerologies is based at least in part on a HARQ transmission associated with a slot associated with the RLC discontinuity and a cyclic redundancy check (CRC) error associated with the slot associated with the RLC discontinuity. 
     Aspect 5: The method of Aspect 3, wherein identifying the one or more numerologies is based at least in part on one or more estimated transport block sizes associated with the RLC discontinuity and an amount of RLC bytes received in a slot associated with the RLC discontinuity. 
     Aspect 6: The method of Aspect 5, wherein the one or more estimated transport block sizes include a first estimated transport block size associated with the first numerology and a second estimated transport block size associated with the second numerology. 
     Aspect 7: The method of Aspect 3, wherein transmitting the RLC status report is based at least in part on receiving a poll protocol data unit associated with the identified one or more numerologies or determining that a reassembly timer for the identified one or more numerologies has expired, and wherein the identified one or more numerologies include a single numerology. 
     Aspect 8: The method of Aspect 3, wherein the identified one or more numerologies include only the first numerology, and wherein transmitting the RLC status report based at least in part on the identified one or more FRs further comprises: transmitting, based at least in part on a poll protocol data unit or expiration of the RLC timer, a negative acknowledgment regarding the RLC discontinuity. 
     Aspect 9: The method of Aspect 3, wherein the identified one or more numerologies include only the first numerology and the RLC timer is a configured RLC timer associated with the first numerology. 
     Aspect 10: The method of Aspect 3, wherein the identified one or more numerologies include the first numerology and the second numerology, and wherein the RLC timer is determined as a longer RLC timer, of an RLC timer associated with the first numerology and an RLC timer associated with the second numerology. 
     Aspect 11: The method of any of Aspects 1-10, wherein the RLC timer is based at least in part on a HARQ parameter associated with a carrier, of the first set of carriers or the second set of carriers, on which the RLC discontinuity is detected. 
     Aspect 12: The method of Aspect 11, wherein the HARQ parameter is at least one of a HARQ round trip time or a HARQ recovery delay. 
     Aspect 13: The method of any of Aspects 1-12, wherein the RLC timer is based at least in part on a combination of the first HARQ parameter and the second HARQ parameter, and based at least in part on a first numerology associated with the first set of carriers and a second numerology associated with the second set of carriers. 
     Aspect 14: The method of any of Aspects 1-13, wherein the RLC discontinuity is an RLC discontinuity on a first carrier of the first set of carriers and a second carrier of the second set of carriers, and wherein the RLC timer is determined in accordance with a lower numerology of a first numerology of the first set of carriers and a second numerology of the second set of carriers. 
     Aspect 15: The method of any of Aspects 1-14, wherein the RLC status report indicates an RLC status up to a most recent RLC discontinuity. 
     Aspect 16: The method of any of Aspects 1-15, wherein detecting the RLC discontinuity further comprises detecting a plurality of RLC discontinuities, and wherein transmitting the RLC status report further comprises: transmitting the RLC status report indicating an RLC status for all RLC discontinuities, of the plurality of RLC discontinuities and associated with the second set of carriers, up to a next RLC discontinuity of the first set of carriers, wherein the second set of carriers is associated with a second numerology that is higher than a first numerology of the first set of carriers. 
     Aspect 17: The method of any of Aspects 1-16, wherein detecting the RLC discontinuity further comprises detecting a plurality of RLC discontinuities, and wherein transmitting the RLC status report further comprises: transmitting the RLC status report indicating an RLC status for all RLC discontinuities, of the plurality of RLC discontinuities, for which the UE estimates that HARQ recovery is complete. 
     Aspect 18: The method of Aspect 17, further comprising: maintaining, for the first set of parameters and the second set of parameters, separate RLC sequence number tracking. 
     Aspect 19: The method of Aspect 17, further comprising: maintaining, for the first set of parameters and the second set of parameters, a separate set of RLC timers. 
     Aspect 20: The method of Aspect 17, wherein the RLC discontinuity is associated with only the second set of carriers, and wherein the RLC status report indicates an RLC status of one or more RLC protocol data units on the second set of carriers after an unacknowledged RLC discontinuity on the first set of carriers. 
     Aspect 21: The method of Aspect 17, wherein an acknowledgment sequence number of the RLC status is set to a most recently received sequence number on the second set of carriers. 
     Aspect 22: The method of any of Aspects 1-21, wherein the first set of parameters or the second set of parameters indicates at least one of: a duplexing configuration, a scheduling delay, a numerology, a frequency range, or an uplink/downlink slot allocation. 
     Aspect 23: The method of any of Aspects 1-22, wherein the first HARQ parameter or the second HARQ parameter includes at least one of: a HARQ round-trip time, or a HARQ recovery delay. 
     Aspect 24: The method of any of Aspects 1-23, wherein detecting the RLC discontinuity further comprises: detecting that a threshold number of retransmitted RLC protocol data units are dropped and that a number of HARQ failures is lower than a threshold. 
     Aspect 25: The method of any of Aspects 1-24, wherein detecting the RLC discontinuity further comprises: detecting that a sum of an inter-carrier sequence number delay between the first set of carriers and the second set of carriers, and the HARQ parameter, is greater than a configured value of the RLC timer. 
     Aspect 26: The method of any of Aspects 1-25, further comprising: determining the RLC timer. 
     Aspect 27: The method of Aspect 26, wherein the RLC timer is equal in length to a HARQ recovery delay indicated by the HARQ parameter. 
     Aspect 28: The method of Aspect 26, wherein determining the RLC timer is based at least in part on a model trained using machine learning. 
     Aspect 29: The method of any of Aspects 1-28, wherein the number of RLC duplicates received by the UE is based at least in part on a successful HARQ transmission following transmission of one or more negative acknowledgments. 
     Aspect 30: A method of wireless communication performed by a user equipment (UE), comprising: transmitting a communication on one of a first set of carriers in a first frequency range (FR) or a second set of carriers in a second FR, wherein the communication is associated with a preferred numerology; receiving a radio link control (RLC) status report indicating an RLC discontinuity associated with the communication; and one of: performing a retransmission of the communication on a preferred carrier associated with the preferred numerology in response to an uplink grant on the preferred carrier being received within a length of time, or performing the retransmission of the communication on a first available uplink grant when no uplink grant on the preferred carrier is received within the length of time. 
     Aspect 31: The method of Aspect 30, wherein the retransmission is on the first available uplink grant of the preferred numerology and the method further comprises: retransmitting the retransmission on a carrier associated with another numerology if no acknowledgment of the retransmission has been received after performing the retransmission. 
     Aspect 32: The method of any of Aspects 30-31, further comprising: transmitting a buffer status report and a power headroom report on a carrier of the first set of carriers; and transmitting the buffer status report and the power headroom report on a carrier of the second set of carriers. 
     Aspect 33: The method of Aspect 32, wherein the buffer status report as transmitted on the carrier of the second set of carriers is updated relative to the buffer status report as transmitted on the carrier of the first set of carriers. 
     Aspect 34: The method of Aspect 32, wherein the buffer status report as transmitted on the carrier of the second set of carriers is merged with another buffer status report triggered after transmission of the buffer status report on the carrier of the first set of carriers. 
     Aspect 35: The method of Aspect 32, wherein the communication is an RLC protocol data unit carrying a poll bit. 
     Aspect 36: A method of wireless communication performed by a user equipment (UE), comprising: transmitting an indication to avoid Voice over New Radio (VoNR) communication in a first frequency range; generating a first transport block (TB) for transmission in the first frequency range, wherein the first TB is generated including a non-zero padding buffer status report or a voice packet; transmitting the first TB in the first frequency range; and transmitting a second TB associated with the VoNR communication in a second frequency range based at least in part on the first TB including the non-zero padding buffer status report or the voice packet. 
     Aspect 37: The method of Aspect 36, further comprising: transmitting the voice packet in the second TB. 
     Aspect 38: The method of Aspect 37, wherein transmitting the voice packet in the second TB is based at least in part on not having received an acknowledgment of the first TB. 
     Aspect 39: An apparatus for wireless communication at a device, 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 one or more of Aspects 1-38. 
     Aspect 40: A device 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 one or more of Aspects 1-38. 
     Aspect 41: An apparatus for wireless communication, comprising at least one means for performing the method of one or more of Aspects 1-38. 
     Aspect 42: A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform the method of one or more of Aspects 1-38. 
     Aspect 43: 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 device, cause the device to perform the method of one or more of Aspects 1-38. 
     The foregoing disclosure provides illustration and description but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects. 
     As used herein, the term “component” is intended to be broadly construed as hardware and/or a combination of hardware and software. “Software” shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, and/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 and/or a combination of hardware and software. It will be apparent that systems and/or methods described herein may be implemented in different forms of hardware and/or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and/or methods is not limiting of the aspects. Thus, the operation and behavior of the systems and/or methods are described herein without reference to specific software code, since those skilled in the art will understand that software and hardware can be designed to implement the systems and/or methods based, at least in part, on the description herein. 
     As used herein, “satisfying a threshold” may, depending on the context, 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, or the like. 
     Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. Many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. The disclosure of various aspects includes each dependent claim in combination with every other claim in the claim set. As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a+b, a+c, b+c, and a+b+c, as well as any combination with multiples of the same element (e.g., a+a, a+a+a, a+a+b, a+a+c, a+b+b, a+c+c, b+b, b+b+b, b+b+c, c+c, and c+c+c, or any other ordering of a, b, and c). 
     No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” are intended to include one or more items and may be used interchangeably with “one or more.” Further, as used herein, the article “the” is intended to include one or more items referenced in connection with the article “the” and may be used interchangeably with “the one or more.” Furthermore, as used herein, the terms “set” and “group” are intended to include one or more items and may be used interchangeably with “one or more.” Where only one item is intended, the phrase “only one” or similar language is used. Also, as used herein, the terms “has,” “have,” “having,” or the like are intended to be open-ended terms that do not limit an element that they modify (e.g., an element “having” A may also have B). Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Also, as used herein, the term “or” is intended to be inclusive when used in a series and may be used interchangeably with “and/or,” unless explicitly stated otherwise (e.g., if used in combination with “either” or “only one of”).