Patent Publication Number: US-2023136275-A1

Title: Sidelink bandwidth part timer based on active state

Description:
FIELD OF THE DISCLOSURE 
     Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for using a sidelink bandwidth part timer that is based on an active state. 
     BACKGROUND 
     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 first user equipment (UE). The method may include starting a sidelink bandwidth part (BWP) timer with a duration that is based at least in part on a timing of a sidelink discontinuous reception (DRX) active state of the first UE. The method may include switching to a first sidelink BWP for the duration of the sidelink BWP timer. 
     Some aspects described herein relate to a first UE for wireless communication. The first UE may include a memory and one or more processors coupled to the memory. The one or more processors may be configured to start a sidelink BWP timer with a duration that is based at least in part on a timing of a sidelink DRX active state of the first UE. The one or more processors may be configured to switch to a first sidelink BWP for the duration of the sidelink BWP timer. 
     Some aspects described herein relate to a non-transitory computer-readable medium that stores a set of instructions for wireless communication by a first UE. The set of instructions, when executed by one or more processors of the first UE, may cause the first UE to start a sidelink BWP timer with a duration that is based at least in part on a timing of a sidelink DRX active state of the first UE. The set of instructions, when executed by one or more processors of the UE, may cause the first UE to switch to a first sidelink BWP for the duration of the sidelink BWP timer. 
     Some aspects described herein relate to an apparatus for wireless communication. The apparatus may include means for starting a sidelink BWP timer with a duration that is based at least in part on a timing of a sidelink DRX active state of the apparatus. The apparatus may include means for switching to a first sidelink BWP for the duration of the sidelink BWP timer. 
     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 herein 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 purposes of illustration and description, and not as a definition of the limits of the claims. 
     While aspects are described in the present disclosure by illustration to some examples, those skilled in the art will understand that such aspects may be implemented in many different arrangements and scenarios. Techniques described herein may be implemented using different platform types, devices, systems, shapes, sizes, and/or packaging arrangements. For example, some aspects may be implemented via integrated chip embodiments or other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, and/or artificial intelligence devices). Aspects may be implemented in chip-level components, modular components, non-modular components, non-chip-level components, device-level components, and/or system-level components. Devices incorporating described aspects and features may include additional components and features for implementation and practice of claimed and described aspects. For example, transmission and reception of wireless signals may include one or more components for analog and digital purposes (e.g., hardware components including antennas, radio frequency (RF) chains, power amplifiers, modulators, buffers, processors, interleavers, adders, and/or summers). It is intended that aspects described herein may be practiced in a wide variety of devices, components, systems, distributed arrangements, and/or end-user devices of varying size, shape, and constitution. 
    
    
     
       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. 
         FIG.  3    is a diagram illustrating an example of sidelink communications, in accordance with the present disclosure. 
         FIG.  4    is a diagram illustrating an example of sidelink communications and access link communications, in accordance with the present disclosure. 
         FIG.  5    is a diagram illustrating an example of sidelink bandwidth parts (BWPs), in accordance with the present disclosure. 
         FIG.  6    is a diagram illustrating an example of a timeline for sidelink discontinuous reception, in accordance with the present disclosure. 
         FIG.  7    is a diagram illustrating an example of using a sidelink BWP timer, in accordance with the present disclosure. 
         FIG.  8    is a diagram illustrating an example of ending timers and an active state, in accordance with the present disclosure. 
         FIG.  9    is a diagram illustrating an example of a call flow for switching BWPs, in accordance with the present disclosure. 
         FIG.  10    is a diagram illustrating an example process performed, for example, by a first UE, in accordance with the present disclosure. 
         FIG.  11    is a diagram of an example apparatus for wireless communication, in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     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 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 . 
     Devices of the wireless network  100  may communicate using the electromagnetic spectrum, which may be subdivided by frequency or wavelength into various classes, bands, channels, or the like. For example, devices of the wireless network  100  may communicate using one or more operating bands. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). 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 start a sidelink bandwidth part (BWP) timer with a duration that is based at least in part on a timing of a sidelink discontinuous reception (DRX) active state of the first UE. The communication manager  140  may switch to a first sidelink BWP for the duration of the sidelink BWP timer. 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 (e.g., with reference to  FIGS.  5 - 11   ). 
     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 (e.g., with reference to  FIGS.  5 - 11   ). 
     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 using a sidelink BWP timer that is based on an active state of the UE  120 , 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  1000  of  FIG.  10   , 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  1000  of  FIG.  10   , 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. 
     In some aspects, a first UE (e.g., UE  120 ) includes means for starting a sidelink BWP timer with a duration that is based at least in part on a timing of a sidelink DRX active state of the first UE; and/or means for switching to a first sidelink BWP for the duration of the sidelink BWP timer. The means for the first UE to perform operations described herein may include, for example, one or more of communication manager  140 , antenna  252 , modem  254 , MIMO detector  256 , receive processor  258 , transmit processor  264 , TX MIMO processor  266 , controller/processor  280 , or memory  282 . 
     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   . 
       FIG.  3    is a diagram illustrating an example  300  of sidelink communications, in accordance with the present disclosure. 
     As shown in  FIG.  3   , a first UE  305 - 1  may communicate with a second UE  305 - 2  (and one or more other UEs  305 ) via one or more sidelink channels  310 . The UEs  305 - 1  and  305 - 2  may communicate using the one or more sidelink channels  310  for P2P communications, D2D communications, V2X communications (e.g., which may include V2V communications, V2I communications, and/or V2P communications) and/or mesh networking. In some aspects, the UEs  305  (e.g., UE  305 - 1  and/or UE  305 - 2 ) may correspond to one or more other UEs described elsewhere herein, such as UE  120 . In some aspects, the one or more sidelink channels  310  may use a PC5 interface and/or may operate in a high frequency band (e.g., the 5.9 GHz band). Additionally, or alternatively, the UEs  305  may synchronize timing of transmission time intervals (TTIs) (e.g., frames, subframes, slots, or symbols) using global navigation satellite system (GNSS) timing. 
     As further shown in  FIG.  3   , the one or more sidelink channels  310  may include a physical sidelink control channel (PSCCH)  315 , a physical sidelink shared channel (PSSCH)  320 , and/or a physical sidelink feedback channel (PSFCH)  325 . The PSCCH  315  may be used to communicate control information, similar to a physical downlink control channel (PDCCH) and/or a physical uplink control channel (PUCCH) used for cellular communications with a base station  110  via an access link or an access channel. The PSSCH  320  may be used to communicate data, similar to a physical downlink shared channel (PDSCH) and/or a physical uplink shared channel (PUSCH) used for cellular communications with a base station  110  via an access link or an access channel. For example, the PSCCH  315  may carry sidelink control information (SCI)  330 , which may indicate various control information used for sidelink communications, such as one or more resources (e.g., time resources, frequency resources, and/or spatial resources) where a transport block (TB)  335  may be carried on the PSSCH  320 . The TB  335  may include data. The PSFCH  325  may be used to communicate sidelink feedback  340 , such as hybrid automatic repeat request (HARD) feedback (e.g., acknowledgement or negative acknowledgement (ACK/NACK) information), transmit power control (TPC), and/or a scheduling request (SR). 
     Although shown on the PSCCH  315 , in some aspects, the SCI  330  may include multiple communications in different stages, such as a first stage SCI (SCI-1) and a second stage SCI (SCI-2). The SCI-1 may be transmitted on the PSCCH  315 . The SCI-2 may be transmitted on the PSSCH  320 . The SCI-1 may include, for example, an indication of one or more resources (e.g., time resources, frequency resources, and/or spatial resources) on the PSSCH  320 , information for decoding sidelink communications on the PSSCH, a quality of service (QoS) priority value, a resource reservation period, a PSSCH demodulation reference signal (DMRS) pattern, an SCI format for the SCI-2, a beta offset for the SCI-2, a quantity of PSSCH DMRS ports, and/or a modulation and coding scheme (MCS). The SCI-2 may include information associated with data transmissions on the PSSCH  320 , such as a hybrid automatic repeat request (HARM) process identifier (ID), a new data indicator (NDI), a source identifier, a destination identifier, and/or a channel state information (CSI) report trigger. 
     In some aspects, the one or more sidelink channels  310  may use resource pools. For example, a scheduling assignment (e.g., included in SCI  330 ) may be transmitted in sub-channels using specific resource blocks (RBs) across time. In some aspects, data transmissions (e.g., on the PSSCH  320 ) associated with a scheduling assignment may occupy adjacent RBs in the same subframe as the scheduling assignment (e.g., using frequency division multiplexing). In some aspects, a scheduling assignment and associated data transmissions are not transmitted on adjacent RBs. 
     In some aspects, a UE  305  may operate using a sidelink transmission mode (e.g., Mode 1) where resource selection and/or scheduling is performed by a base station  110 . For example, the UE  305  may receive a grant (e.g., in downlink control information (DCI) or in a radio resource control (RRC) message, such as for configured grants) from the base station  110  for sidelink channel access and/or scheduling. In some aspects, a UE  305  may operate using a transmission mode (e.g., Mode 2) where resource selection and/or scheduling is performed by the UE  305  (e.g., rather than a base station  110 ). In some aspects, the UE  305  may perform resource selection and/or scheduling by sensing channel availability for transmissions. For example, the UE  305  may measure an RSSI parameter (e.g., a sidelink-RSSI (S-RSSI) parameter) associated with various sidelink channels, may measure an RSRP parameter (e.g., a PSSCH-RSRP parameter) associated with various sidelink channels, and/or may measure an RSRQ parameter (e.g., a PSSCH-RSRQ parameter) associated with various sidelink channels, and may select a channel for transmission of a sidelink communication based at least in part on the measurement(s). 
     Additionally, or alternatively, the UE  305  may perform resource selection and/or scheduling using SCI  330  received in the PSCCH  315 , which may indicate occupied resources and/or channel parameters. Additionally, or alternatively, the UE  305  may perform resource selection and/or scheduling by determining a channel busy rate (CBR) associated with various sidelink channels, which may be used for rate control (e.g., by indicating a maximum number of resource blocks that the UE  305  can use for a particular set of subframes). 
     In the transmission mode where resource selection and/or scheduling is performed by a UE  305 , the UE  305  may generate sidelink grants, and may transmit the grants in SCI  330 . A sidelink grant may indicate, for example, one or more parameters (e.g., transmission parameters) to be used for an upcoming sidelink transmission, such as one or more resource blocks to be used for the upcoming sidelink transmission on the PSSCH  320  (e.g., for TBs  335 ), one or more subframes to be used for the upcoming sidelink transmission, and/or a modulation and coding scheme (MCS) to be used for the upcoming sidelink transmission. In some aspects, a UE  305  may generate a sidelink grant that indicates one or more parameters for semi-persistent scheduling (SPS), such as a periodicity of a sidelink transmission. Additionally, or alternatively, the UE  305  may generate a sidelink grant for event-driven scheduling, such as for an on-demand sidelink message. 
     As indicated above,  FIG.  3    is provided as an example. Other examples may differ from what is described with respect to  FIG.  3   . 
       FIG.  4    is a diagram illustrating an example  400  of sidelink communications and access link communications, in accordance with the present disclosure. 
     As shown in  FIG.  4   , a transmitter (Tx)/receiver (Rx) UE  405  and an Rx/Tx UE  410  may communicate with one another via a sidelink, as described above in connection with  FIG.  3   . As further shown, in some sidelink modes, a base station  110  may communicate with the Tx/Rx UE  405  via a first access link. Additionally, or alternatively, in some sidelink modes, the base station  110  may communicate with the Rx/Tx UE  410  via a second access link. The Tx/Rx UE  405  and/or the Rx/Tx UE  410  may correspond to one or more UEs described elsewhere herein, such as the UE  120  of  FIG.  1   . Thus, a direct link between UEs  120  (e.g., via a PC5 interface) may be referred to as a sidelink, and a direct link between a base station  110  and a UE  120  (e.g., via a Uu interface) may be referred to as an access link. Sidelink communications may be transmitted via the sidelink, and access link communications may be transmitted via the access link. An access link communication may be either a downlink communication (from a base station  110  to a UE  120 ) or an uplink communication (from a UE  120  to a base station  110 ). 
     As indicated above,  FIG.  4    is provided as an example. Other examples may differ from what is described with respect to  FIG.  4   . 
       FIG.  5    is a diagram illustrating an example  500  of sidelink BWPs, in accordance with the present disclosure. 
     A UE may use a BWP as a part of available bandwidth to save power. The UE may be configured with multiple BWPs (e.g., maximum 4 BWPs per carrier for downlink and uplink, respectively), but only one BWP is active for downlink and only one BWP is active for uplink per carrier at a specific time. When a base station, such as a gNB, configures a BWP for the UE, the gNB may include parameters such as a BWP numerology (subcarrier spacing (SCS) and cyclic prefix type), a BWP bandwidth size, a frequency location, and a control resource set (CORESET). UEs are expected to receive and transmit only within the frequency range configured for the active BWPs, with the associated numerologies. However, there are exceptions. For example, the UE may perform radio resource management (RRM) measurements or transmit a sounding reference signal (SRS) in a measurement gap that is outside of the active BWP. 
     A gNB may activate, deactivate, or switch to a BWP with dedicated radio resource control (RRC) signaling (e.g., via RRC reconfiguration with different BWP(s)), a medium access control control element (MAC CE) (e.g., a MAC CE containing a BWP ID, a DCI 0_1 for uplink (e.g., a scheduling DCI indicating a BWP indicator), or a DCI 1_0 for downlink. The UE may also switch to a BWP based on a BWP inactivity timer (bwp-inactivityTimer). For example, the UE may switch to a default BWP when the BWP inactivity timer expires. 
     BWPs may also be used for sidelink (SL). However, only one BWP is configured and activated for all UEs on a sidelink carrier. Only one carrier is supported on sidelink for NR V2X (i.e., no multi-carrier support on sidelink). 
     In addition to sidelink BWPs, a UE may be configured for sidelink DRX. Sidelink DRX involves the UE sleeping (inactive state for off-duration) and waking (active state for on-duration) during a sidelink DRX cycle. A sidelink DRX configuration may be negotiated between paired UEs and configured per communication direction between the paired UEs using unicast. The sidelink DRX configuration may be determined by a transmitting UE for the traffic direction from the transmitting UE, with assistance information from a receiving UE. For unicast, the UE may support an on-duration timer, an inactivity timer, a HARQ round trip time (RTT) timer, and/or a HARQ retransmission timer. 
     Sidelink DRX may also be used for groupcast and configured per QoS and Layer 2 (L2) destination ID. For example, there may be a sidelink DRX cycle per QoS and a sidelink DRX offset per L2 destination ID. The on-duration timer, the inactivity timer, and the HARQ timers may be supported for groupcast. 
     Sidelink DRX may be used for broadcast. Sidelink DRX for broadcast may be configured per QoS and per L2 Destination ID (e.g., sidelink DRX cycle per QoS, sidelink DRX offset per L2 Destination ID). The on-duration timer may be supported. 
     Example  500  shows that a UE may be configured with multiple sidelink BWPs and multiple sidelink DRXs for multiple communications (e.g., unicast, groupcast or broadcast) of different services. For example, in scenarios  502 ,  504 ,  506 , and  508  in example  500 , SL BWP1 and SL DRX1 are for communication 1 of service 1, and SL BWP2 and SL DRX2 are for communication 2 of service 2. 
     If there is no overlapping between the active states of SL DRX1 and SL DRX2 (such as in scenarios  502  and  504 ), both the transmitting UE and the receiving UE are to switch their active sidelink BWPs in frequency according to the active states in time. If there is overlapping between the two active states in time (scenarios  506  and  508 ), both the transmitting UE and the receiving UE are to determine whether to switch their active sidelink BWPs during the overlapped active states, since the UEs can operate with only one active sidelink BWP at a time. Note that for sidelink, the scheduling SCI (e.g., SCI 1) is transmitted together with a data packet, which prohibits using scheduling SCI to dynamically indicate sidelink BWP switching. That is, if UEs are operating with multiple sidelink BWPs and sidelink DRXs for different services or communications, without cooperation, sidelink BWPs may overlap during active states and cause interference or other signal degradation, which wastes processing resources and signaling resources of the UEs. 
     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 a timeline for sidelink DRX, in accordance with the present disclosure. Example  600  shows different sidelink BWPs (e.g., SL BWP1 and SL BWP2) and different sidelink DRXs (e.g., SL DRX1 and SL DRX2) that are formed for communications (e.g., broadcasts, groupcasts or unicast) associated with various services on a sidelink carrier. 
     As shown in example  600 , a UE may switch to an active sidelink BWP in frequency (sl-bwp1) to enter a sidelink DRX active state in time (active1) for an on-duration duration (SL-DRX On1) for sidelink communications of a service. The UE may stay in the active state (active1), which may be extended by a sidelink DRX inactivity timer (inactivity1) and/or a HARQ retransmission timer (HARQretran1). The UE may stay with its active sidelink BWP (sl-bwp1) even through its inactive state (sleep1) until switching to another active state (active2) in another sidelink BWP (sl-bwp2) for another sidelink DRX on-duration (SL-DRX On2) for sidelink communications of another service. However, maintaining an active sidelink BWP during an inactive state may unnecessarily consume extra power, especially when the active sidelink BWP is a wide frequency band. 
     As indicated above,  FIG.  6    is provided as an example. Other examples may differ from what is described with regard to  FIG.  6   . 
       FIG.  7    is a diagram illustrating an example  700  of using a sidelink BWP timer, in accordance with the present disclosure. 
     According to various aspects described herein, a UE (e.g., a UE  120 , UE  405 ) may save power during an inactive state by switching an active sidelink BWP based at least in part on an active state of the UE. For example, the UE may start a sidelink BWP timer with a duration that is based at least in part on a timing of a sidelink DRX active state of the UE. The timing may include an on-duration for the sidelink DRX active state. In some aspects, the sidelink BWP timer may be equal to or similar to the on-duration for the sidelink DRX active state. 
     The sidelink BWP timer may be based at least in part on information about a configuration of the sidelink BWP and a configuration of the sidelink DRX cycle. The UE may switch to a first sidelink BWP and remain in the first sidelink BWP during the time when sidelink BWP timer is running. When the sidelink BWP timer expires, the UE may leave the first sidelink BWP. The UE may switch to a second sidelink BWP, which may be a default BWP. 
     Example  700  shows a UE that may operate with two non-overlapping active states in time (e.g., active state of SL DRX 1 and active state of SL DRX2) with two different active sidelink BWPs in frequency, respectively. The UE may set its active sidelink BWP based at least in part on a timing of the sidelink DRX active state. That is, the UE may operate in a first sidelink BWP while in the active state (e.g., an active sidelink BWP for active state) and then switch to a second sidelink BWP (e.g., a sidelink BWP for inactive state), such as a default sidelink BWP (SL-BWP-default) with a narrow bandwidth or a sleep sidelink BWP (SL-BWP-sleep) with zero bandwidth. 
     For example, as shown by reference number  702 , the UE may switch to a first sidelink BWP (e.g., sl-bwp1 for a first active state). As shown by reference number  704 , the UE may start a sidelink BWP timer (sl-bwp-timer), where the sidelink BWP timer is set with a duration that is based on the sidelink DRX on-duration (SL-DRX On1) (e.g., equal or larger than the on-duration). The UE may extend the active state based at least in part on the inactivity timer or the HARQ retransmission timer. That is, the UE may extend the duration of the sidelink BWP timer when extending the active state in time. For example, the UE may extend a length of the duration of the sidelink BWP timer when the active state is extended via a sidelink DRX inactivity timer (inactivity1) or a HARQ retransmission timer (HARQretran1) (e.g., extend the sidelink BWP timer to an end of the sidelink DRX inactivity timer or an end of the HARQ retransmission timer), staying with the active sidelink BWP throughout the active state. 
     Upon expiration of the sidelink BWP timer, as shown by reference number  706 , the UE may switch to a second sidelink BWP, such as a default sidelink BWP (sl-bwp-default), an initial sidelink BWP, or a common sidelink BWP with a narrow bandwidth (e.g., narrower than the bandwidth of the sidelink BWP for an active state). The second sidelink BWP may also be a “sleep” sidelink BWP with zero bandwidth. Switching to the second sidelink BWP may save the UE power during the inactive state (e.g., a narrow bandwidth sidelink BWP or a zero bandwidth sidelink BWP). By tying the duration of a sidelink BWP timer to the duration of the sidelink DRX active state, the UE may switch to a narrow bandwidth or zero bandwidth sidelink BWP sooner and conserve more power. 
     As shown by reference number  708 , the UE may switch to another active BWP (sl-bwp2 for a second active state) when the sidelink BWP timer expires. As shown by reference number  710 , the UE may start the sidelink BWP timer, where the duration of the sidelink BWP timer is set based on the other sidelink DRX on-duration (SL-DRX On2). 
     As indicated above,  FIG.  7    is provided as an example. Other examples may differ from what is described with regard to  FIG.  7   . 
       FIG.  8    is a diagram illustrating an example  800  of ending timers and an active state, in accordance with the present disclosure. Example  800  shows a first UE (e.g., a UE  120 , UE  405 ) that operates with two active states, such as an active state of SL DRX 1 (active1) and an active state of SL DRX2 (active2), that could overlap in different active sidelink BWPs. 
     As described in connection with  FIG.  7   , the first UE may extend the sidelink DRX active state based at least in part on the inactivity timer and/or the HARQ retransmission timer. The first UE may determine if the extended sidelink DRX active state is to overlap with the active state of another sidelink DRX. To avoid the overlap of the active states, the first UE may end its active state earlier than the expiration of the sidelink DRX timer and end its active sidelink BWP accordingly, as shown by reference number  802 . The first UE may transmit an indication (e.g., a PC5 RRC message, a MAC CE command or an SCI) to a second UE (e.g., a UE  120 , UE  410 ) that indicates that the second UE is to end all sidelink BWP and DRX timers and end the active state of the second UE. 
     In some aspects, the first UE may end the active state and the timers even earlier, as shown by reference number  804 . For example, the first UE may end the active state during an inactivity timer running duration or at the end of an inactivity timer running duration and before the end of a HARQ retransmission timer running duration, even though the sidelink BWP timer was extended to the end of the HARQ retransmission timer. In some aspects, the first UE may end the active state early, as shown by reference number  806  (e.g., during the on-duration). By ending earlier, depending upon traffic conditions (e.g., transmitting no more data, or dropping or delaying lower priority, long latency or low reliability data transmissions with a congested channel) and a UE status (e.g., type of UE, power consumption of the UE, battery status of the UE), the first UE may conserve power and avoid overlap with another sidelink DRX active state in another sidelink BWP that could degrade communications. Avoiding degraded communications conserves processing resources and signaling resources. 
     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 a call flow for switching BWPs, in accordance with the present disclosure. Example  900  shows UEs that may communicate with each other on a sidelink, including UE  910 , UE  920 , UE  930 , and UEs  940 . 
     As shown by reference number  942 , the UEs may be configured (or preconfigured) with multiple sidelink BWPs (e.g., SL BWP1 and SL BWP2 shown in  FIGS.  7  and  8   ) and sidelink DRXs (e.g., SL DRX1 and SL DRX2 shown in  FIGS.  7  and  8   ) for multiple services (e.g., Service1, Service2), respectively. 
     As shown by reference number  944 , UE  910  may switch to a first active sidelink BWP (e.g., SL BWP1 shown in  FIGS.  7  and  8   ) for a first sidelink DRX (e.g., SL DRX1 shown in  FIGS.  7  and  8   ) of a first service (Service1). UE  910  may start a sidelink BWP timer (e.g., sl-bwp-timer) that is set based at least in part on the on-duration (e.g., SL-DRX On1) of the SL DRX1 active state. As shown by reference number  946 , UE  920  may likewise switch to the first active sidelink BWP1 for the first sidelink DRX and start the sidelink BWP timer that is set based at least in part on the on-duration of the SL DRX1 active state. As shown by reference number  948 , UE  910  may transmit and receive sidelink communications with UE  920  during the active state with the sidelink BWP timer running. 
     As shown by reference numbers  950  and  952 , UE  910  and UE  920  may extend the sidelink BWP timer based on a sidelink DRX inactivity timer (e.g., inactivity1 shown in  FIGS.  7  and  8   ) and/or a HARQ retransmission timer (e.g., HARQretran1 shown in  FIGS.  7  and  8   ), and operate with the active sidelink BWP during the extended first active state. As shown by reference number  954 , UE  910  may determine if the extended first active state (e.g., active1 shown in  FIGS.  7  and  8   ) overlaps with a second active state of a second SL DRX (e.g., active2). As shown by reference number  956 , UE  910  may determine to end the extended first active state before the expiration of the sidelink DRX and BWP timers to avoid the overlapping of two active states with two active sidelink BWPs (e.g., overlapping of sl-bwp1 and sl-bwp2, shown in  FIGS.  7  and  8   ). As shown by reference number  958 , UE  910  may transmit an indication (e.g., a MAC CE command) to UE  920  to indicate the forced ending of the first active state and the ending of all running timers. UE  920  may end its timers and active state early based on the received indication. 
     As shown by reference numbers  960  and  962 , UE  910  and UE  930  may switch to a second active sidelink BWP (e.g., sl-bwp2 shown in  FIGS.  7  and  8   ) for a second sidelink DRX active state of a second service and start the sidelink BWP timer that is set based at least in part on the on-duration of the second sidelink DRX active state. As shown by reference number  964 , UE  920  may switch to another sidelink BWP, such as default sidelink BWP (e.g., sl-bwp-default as shown in  FIG.  3   ) or a sleep sidelink BWP for the inactive state to save power. As shown by reference number  966 , UE  910  and UE  930  may communicate for the second service during the active state with the sidelink BWP timer running. 
     As shown by reference numbers  968  and  970 , UE  920  and UEs  940  may switch to a third active sidelink BWP for a third sidelink DRX active state of a third service and start the sidelink BWP timer that is set based at least in part on the on-duration of the third sidelink DRX active state. As shown by reference number  972 , UE  920  and UE  940  s may communicate for the third service during the active state with the sidelink BWP timer running. The third service may involve a groupcast or broadcast for a service with the UEs  940 . 
     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 process  1000  performed, for example, by a first UE, in accordance with the present disclosure. Example process  1000  is an example where the first UE (e.g., a UE  120 , UE  405 ) performs operations associated with a sidelink BWP timer that is based on an active state of the first UE. 
     As shown in  FIG.  10   , in some aspects, process  1000  may include starting a sidelink BWP timer with a duration that is based at least in part on a timing of a sidelink DRX active state of the first UE (block  1010 ). For example, the first UE (e.g., using communication manager  140  and/or timer component  1108  depicted in  FIG.  11   ) may start a sidelink BWP timer with a duration that is based at least in part on a timing of a sidelink DRX active state of the first UE, as described above. 
     As further shown in  FIG.  10   , in some aspects, process  1000  may include switching to a first sidelink BWP for the duration of the sidelink BWP timer (block  1020 ). For example, the first UE (e.g., using communication manager  140  and/or BWP component  1110  depicted in  FIG.  11   ) may switch to a first sidelink BWP for the duration of the sidelink BWP timer, as described above. 
     Process  1000  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  1000  includes receiving information associated with a sidelink BWP configuration and a sidelink DRX configuration, where starting the timer includes starting the timer based at least in part on the information. 
     In a second aspect, alone or in combination with the first aspect, process  1000  includes setting the duration of the sidelink BWP timer based at least in part on an on-duration for the sidelink DRX active state. In a third aspect, alone or in combination with one or more of the first and second aspects, process  1000  includes extending the duration of the sidelink BWP timer based at least in part on one or more of a duration of a sidelink DRX inactivity timer or a duration of a HARQ retransmission timer. 
     In a fourth aspect, alone or in combination with one or more of the first through third aspects, process  1000  includes extending the sidelink DRX active state (or the on-duration for the sidelink DRX active state) based at least in part on one or more of the duration of the sidelink DRX inactivity timer or the duration of the HARQ retransmission timer. 
     In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, process  1000  includes switching to a second sidelink BWP (e.g., default BWP) upon expiration of the sidelink BWP timer. In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the second sidelink BWP includes a bandwidth that is narrower than bandwidths of available sidelink BWPs. In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the second sidelink BWP includes a sleep sidelink BWP with zero bandwidth. 
     In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, process  1000  includes ending the sidelink BWP timer before the sidelink BWP timer expires, and transmitting, to a second UE, an indication (e.g., MAC CE) that indicates that a sidelink BWP timer of the second UE is to end before the sidelink BWP timer of the second UE expires. 
     In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, process  1000  includes ending the sidelink DRX active state of the first UE before a scheduled end of the sidelink DRX active state (e.g., based at least in part on one or more of an on duration timer, an inactivity timer, or a hybrid automatic repeat request retransmission timer), where the indication indicates that a sidelink DRX active state of the second UE is to end before a scheduled end (end of configured on-duration) of the sidelink DRX active state of the second UE. 
     In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, process  1000  includes receiving, from a second UE, an indication (e.g., MAC CE) that indicates that the sidelink BWP timer is to end before the sidelink BWP timer expires, and ending the sidelink BWP timer before the sidelink BWP timer expires. In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, the indication indicates that the sidelink DRX active state of the first UE is to end before a scheduled end (end of configured on-duration) of the sidelink DRX active state of the first UE based at least in part on one or more of an on duration timer, an inactivity timer, or a hybrid automatic repeat request retransmission timer, and process  1000  includes ending the sidelink DRX active state of the first UE before the scheduled end of the sidelink DRX active state of the first UE. 
     In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, the sidelink BWP timer is associated with a groupcast or broadcast sidelink service. 
     Although  FIG.  10    shows example blocks of process  1000 , in some aspects, process  1000  may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in  FIG.  10   . Additionally, or alternatively, two or more of the blocks of process  1000  may be performed in parallel. 
       FIG.  11    is a diagram of an example apparatus  1100  for wireless communication. The apparatus  1100  may be a first UE (e.g., UE  120 ), or a first UE may include the apparatus  1100 . In some aspects, the apparatus  1100  includes a reception component  1102  and a transmission component  1104 , 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  1100  may communicate with another apparatus  1106  (such as a UE, a base station, or another wireless communication device) using the reception component  1102  and the transmission component  1104 . As further shown, the apparatus  1100  may include the communication manager  140 . The communication manager  140  may include a timer component  1108 , a BWP component  1110 , and/or a DRX component  1112 , among other examples. 
     In some aspects, the apparatus  1100  may be configured to perform one or more operations described herein in connection with  FIGS.  1 - 9   . Additionally, or alternatively, the apparatus  1100  may be configured to perform one or more processes described herein, such as process  1000  of  FIG.  10   . In some aspects, the apparatus  1100  and/or one or more components shown in  FIG.  11    may include one or more components of the first UE described in connection with  FIG.  2   . Additionally, or alternatively, one or more components shown in  FIG.  11    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  1102  may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus  1106 . The reception component  1102  may provide received communications to one or more other components of the apparatus  1100 . In some aspects, the reception component  1102  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  1100 . In some aspects, the reception component  1102  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 first UE described in connection with  FIG.  2   . 
     The transmission component  1104  may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus  1106 . In some aspects, one or more other components of the apparatus  1100  may generate communications and may provide the generated communications to the transmission component  1104  for transmission to the apparatus  1106 . In some aspects, the transmission component  1104  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  1106 . In some aspects, the transmission component  1104  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 first UE described in connection with  FIG.  2   . In some aspects, the transmission component  1104  may be co-located with the reception component  1102  in a transceiver. 
     The timer component  1108  may start a sidelink BWP timer with a duration that is based at least in part on a timing of a sidelink DRX active state of the first UE. The BWP component  1110  may switch to a first sidelink BWP for the duration of the sidelink BWP timer. The reception component  1102  may receive information associated with a sidelink BWP configuration and a sidelink DRX configuration, where starting the timer includes starting the timer based at least in part on the information. 
     The timer component  1108  may set the duration of the sidelink BWP timer based at least in part on an on-duration for the sidelink DRX active state. The timer component  1108  may extend the duration of the sidelink BWP timer based at least in part on one or more of a duration of a sidelink DRX inactivity timer or a duration of a HARQ retransmission timer. The timer component  1108  may extend the on-duration for the sidelink DRX active state based at least in part on one or more of the duration of the sidelink DRX inactivity timer or the duration of the HARQ retransmission timer. The BWP component  1110  may switch to a default BWP upon expiration of the sidelink BWP timer. 
     The timer component  1108  may end the sidelink BWP timer before the sidelink BWP timer expires. The transmission component  1104  may transmit, to a second UE, an indication (e.g., MAC CE) that indicates that a sidelink BWP timer of the second UE is to end before the sidelink BWP timer of the second UE expires. 
     The DRX component  1112  may end the sidelink DRX active state of the first UE before a scheduled end (end of configured on-duration) for the sidelink DRX active state, where the indication indicates that a sidelink DRX active state of the second UE is to end before a scheduled end (end of configured on-duration) for the sidelink DRX active state of the second UE. 
     The reception component  1102  may receive, from a second UE, a MAC CE that indicates that the sidelink BWP timer is to end before the sidelink BWP timer expires. The timer component  1108  may end the sidelink BWP timer before the sidelink BWP timer expires. 
     The number and arrangement of components shown in  FIG.  11    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.  11   . Furthermore, two or more components shown in  FIG.  11    may be implemented within a single component, or a single component shown in  FIG.  11    may be implemented as multiple, distributed components. Additionally, or alternatively, a set of (one or more) components shown in  FIG.  11    may perform one or more functions described as being performed by another set of components shown in  FIG.  11   . 
     The following provides an overview of some Aspects of the present disclosure: 
     Aspect 1: A method of wireless communication performed by a first user equipment (UE), comprising: starting a sidelink bandwidth part (BWP) timer with a duration that is based at least in part on a timing of a sidelink discontinuous reception (DRX) active state of the first UE; and switching to a first sidelink BWP for the duration of the sidelink BWP timer. 
     Aspect 2: The method of Aspect 1, further comprising receiving information associated with a sidelink BWP configuration and a sidelink DRX configuration, wherein starting the timer includes starting the timer based at least in part on the information. 
     Aspect 3: The method of Aspect 1 or 2, further comprising setting the duration of the sidelink BWP timer based at least in part on an on duration for the sidelink DRX active state. 
     Aspect 4: The method of Aspect 3, further comprising extending the duration of the sidelink BWP timer based at least in part on one or more of a duration of a sidelink DRX inactivity timer or a duration of a hybrid automatic repeat request (HARQ) retransmission timer. 
     Aspect 5: The method of Aspect 4, further comprising extending the sidelink DRX active state based at least in part on one or more of the duration of the sidelink DRX inactivity timer or the duration of the HARQ retransmission timer. 
     Aspect 6: The method of any of Aspects 1-5, further comprising switching to a second sidelink BWP upon expiration of the sidelink BWP timer. 
     Aspect 7: The method of Aspect 6, wherein the second sidelink BWP includes a bandwidth that is narrower than bandwidths of available sidelink BWPs. 
     Aspect 8: The method of Aspect 6, wherein the second sidelink BWP includes a sleep sidelink BWP with zero bandwidth. 
     Aspect 9: The method of any of Aspects 1-8, further comprising: ending the sidelink BWP timer before the sidelink BWP timer expires; and transmitting, to a second UE, an indication that indicates that a sidelink BWP timer of the second UE is to end before the sidelink BWP timer of the second UE expires. 
     Aspect 10: The method of Aspect 9, further comprising ending the sidelink DRX active state of the first UE before a scheduled end of the sidelink DRX active state based at least in part on one or more of an on duration timer, an inactivity timer, or a hybrid automatic repeat request retransmission timer, wherein the indication indicates that a sidelink DRX active state of the second UE is to end before a scheduled end of the sidelink DRX active state of the second UE. 
     Aspect 11: The method of Aspect 9, wherein the indication includes a medium access control control element (MAC CE). 
     Aspect 12: The method of any of Aspects 1-11, further comprising: receiving, from a second UE, an indication that indicates that the sidelink BWP timer is to end before the sidelink BWP timer expires; and ending the sidelink BWP timer before the sidelink BWP timer expires. 
     Aspect 13: The method of Aspect 12, wherein the indication indicates that the sidelink DRX active state of the first UE is to end before a scheduled end of the sidelink DRX active state of the first UE based at least in part on one or more of an on duration timer, an inactivity timer, or a hybrid automatic repeat request retransmission timer, and wherein the method further comprises ending the sidelink DRX active state of the first UE before the scheduled end of the sidelink DRX active state of the first UE. 
     Aspect 14: The method of any of Aspects 1-13, wherein the sidelink BWP timer is associated with a groupcast or broadcast sidelink service. 
     Aspect 15: 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 1-14. 
     Aspect 16: 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 1-14. 
     Aspect 17: An apparatus for wireless communication, comprising at least one means for performing the method of one or more of Aspects 1-14. 
     Aspect 18: 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 1-14. 
     Aspect 19: 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 1-14. 
     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”).