Patent Publication Number: US-2022225375-A1

Title: Methods and apparatus for transmitting sidelink control messages

Description:
BACKGROUND 
     Aspects of the present disclosure relate generally to wireless communications, and more particularly, to apparatuses and methods for transmitting sidelink control messages. 
     Wireless communication networks are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems 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, and single-carrier frequency division multiple access (SC-FDMA) systems. 
     These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. For example, a fifth generation (5G) wireless communications technology (which may be referred to as new radio (NR)) is envisaged to expand and support diverse usage scenarios and applications with respect to current mobile network generations. In an aspect, 5G communications technology may include: enhanced mobile broadband addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable-low latency communications (URLLC) with certain specifications for latency and reliability; and massive machine type communications, which may allow a very large number of connected devices and transmission of a relatively low volume of non-delay-sensitive information. As the demand for mobile broadband access continues to increase, however, further improvements in NR communications technology and beyond may be desired. 
     In a wireless communication network, sidelink communications between wireless devices, such as a programmable logical controller (PLC) and a sensor/actuator (SA), may require the exchange of sidelink control information (SCI), such as inter-user equipment (UE) coordination (e.g., resource selection, collision detection, etc.), channel state information (CSI) report, hybrid automatic repeat request (HARQ), scheduling request, etc. The types of SCI may include control messages from SA (or client) to PLC (or anchor), also known as sidelink uplink control information (S-UCI), and control messages from PLC to SA, also known as sidelink downlink control information (S-DCI). In conventional networks, SCI transmission may be appended to physical sidelink control channel (PSCCH) or physical sidelink shared channel (PSSCH). In particular, SCI transmissions may not be possible if no data is transmitted in PSSCH, or the SCI may occupy the entire slot. However, allotting an entire slot for transmitting SCI when no data is transmitted may be inefficient. Therefore, improvements may be desirable. 
     SUMMARY 
     The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later. 
     Aspects of the present disclosure include methods by a user equipment (UE) for receiving first scheduling information indicating a sidelink uplink control information (S-UCI) resource, receiving second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and transmitting control information via at least one of the S-UCI resource or the one or more PSFCH resources. 
     Other aspects of the present disclosure include a user equipment (UE) having a memory comprising instructions, a transceiver, and one or more processors operatively coupled with the memory and the transceiver, the one or more processors configured to execute instructions in the memory to receive, via the transceiver, first scheduling information indicating a sidelink uplink control information (S-UCI) resource, receive, via the transceiver, second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and transmit, via the transceiver, control information via at least one of the S-UCI resource or the one or more PSFCH resources. 
     An aspect of the present disclosure includes a user equipment (UE) including means for receiving first scheduling information indicating a sidelink uplink control information (S-UCI) resource, means for receiving second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and means for transmitting control information via at least one of the S-UCI resource or the one or more PSFCH resources. 
     Some aspects of the present disclosure include non-transitory computer readable media having instructions stored therein that, when executed by one or more processors of a user equipment (UE), cause the one or more processors to receive first scheduling information indicating a sidelink uplink control information (S-UCI) resource, receive second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and transmit control information via at least one of the S-UCI resource or the one or more PSFCH resources. 
     Aspects of the present disclosure include methods by a user equipment (UE) for identifying first scheduling information indicating a sidelink downlink control information (S-DCI) resource, identifying second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and transmitting control information via at least one of the S-DCI resource or the one or more PSFCH resources. 
     Other aspects of the present disclosure include a user equipment (UE) having a memory comprising instructions, a transceiver, and one or more processors operatively coupled with the memory and the transceiver, the one or more processors configured to execute instructions in the memory to identify first scheduling information indicating a sidelink downlink control information (S-DCI) resource, identify second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and transmit, via the transceiver, control information via at least one of the S-DCI resource or the one or more PSFCH resources. 
     An aspect of the present disclosure includes a user equipment (UE) including means for identifying first scheduling information indicating a sidelink downlink control information (S-DCI) resource, means for identifying second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and means for transmitting control information via at least one of the S-DCI resource or the one or more PSFCH resources. 
     Some aspects of the present disclosure include non-transitory computer readable media having instructions stored therein that, when executed by one or more processors of a user equipment (UE), cause the one or more processors to identify first scheduling information indicating a sidelink downlink control information (S-DCI) resource, identify second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and transmit control information via at least one of the S-DCI resource or the one or more PSFCH resources. 
     Aspects of the present disclosure include methods by a user equipment (UE) for transmitting first-stage sidelink control information (SCI- 1 ) in a first resource and transmitting second-stage sidelink control information (SCI- 2 ), after transmitting the SCI- 1 , in a second resource, wherein the SCI- 2  includes a new data indicator (NDI) value indicating that the SCI- 2  is a retransmission of the SCI- 1 . 
     Other aspects of the present disclosure include a user equipment (UE) having a memory comprising instructions, a transceiver, and one or more processors operatively coupled with the memory and the transceiver, the one or more processors configured to execute instructions in the memory to transmit, via the transceiver, first-stage sidelink control information (SCI- 1 ) in a first resource and transmit, via the transceiver, second-stage sidelink control information (SCI- 2 ), after transmitting the SCI- 1 , in a second resource, wherein the SCI- 2  includes a new data indicator (NDI) value indicating that the SCI- 2  is a retransmission of the SCI- 1 . 
     An aspect of the present disclosure includes a user equipment (UE) including means for transmitting first-stage sidelink control information (SCI- 1 ) in a first resource and means for transmitting second-stage sidelink control information (SCI- 2 ), after transmitting the SCI- 1 , in a second resource, wherein the SCI- 2  includes a new data indicator (NDI) value indicating that the SCI- 2  is a retransmission of the SCI- 1 . 
     Some aspects of the present disclosure include non-transitory computer readable media having instructions stored therein that, when executed by one or more processors of a user equipment (UE), cause the one or more processors to transmit first-stage sidelink control information (SCI- 1 ) in a first resource and transmit second-stage sidelink control information (SCI- 2 ), after transmitting the SCI- 1 , in a second resource, wherein the SCI- 2  includes a new data indicator (NDI) value indicating that the SCI- 2  is a retransmission of the SCI- 1 . 
     To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements, and in which: 
         FIG. 1  is a diagram illustrating an example of a wireless communications system and an access network according to aspects of the present disclosure; 
         FIG. 2  is a schematic diagram of an example of a user equipment according to aspects of the present disclosure; 
         FIG. 3  is a schematic diagram of an example of a base station according to aspects of the present disclosure; 
         FIG. 4  illustrates an example of an environment  400  of wireless communication between devices based on V2X/V2V/D2D communication according to aspects of the present disclosure; 
         FIG. 5  illustrates example aspects of a sidelink physical layer structure according to aspects of the present disclosure; 
         FIG. 6  illustrates an example of resources used for sidelink communication according to aspects of the present disclosure; 
         FIG. 7  illustrates an example of overlapping S-UCI and PSFCH resources according to aspects of the present disclosure; 
         FIG. 8  illustrates an example of overlapping S-DCI and PSFCH resources according to aspects of the present disclosure; 
         FIG. 9  is an example of a method for transmitting uplink sidelink control information according to aspects of the present disclosure; 
         FIG. 10  is an example of a method for transmitting downlink sidelink control information according to aspects of the present disclosure; and 
         FIG. 11  is an example of a method for transmitting sidelink control information according to aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts. 
     Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. 
     By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on a chip (SoC), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. 
     Accordingly, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that may be accessed by a computer. By way of example, and not limitation, such computer-readable media may comprise a random-access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that may be used to store computer executable code in the form of instructions or data structures that may be accessed by a computer. 
     In one implementation, user equipments (UEs) may communicate with each other directly via sidelink communication protocols, with or without involving a base station. Examples of UEs may include programmable logical controllers (PLCs) and sensors/actuators (SAs). In an example, a PLC may communicate directly with one or more SAs (i.e., sidelink communication). The control information for supporting the sidelink communication may be transmitted by the PLC to the one or more SAs (i.e., sidelink downlink control information, or S-DCI), and/or from the one or more SAs to the PLC (i.e., sidelink uplink control information, or S-UCI). 
     In one aspect of the present disclosure, a base station (BS) or the PLC may schedule S-UCI resources and physical sidelink feedback channel (PSFCH) resources for the uplink transmission of control information by the one or more SAs. In a first implementation, the one or more SAs may transmit the control information in both the S-UCI resources and the PSFCH resources. In a second implementation, the one or more SAs may choose the earliest resources (of the S-UCI resources and the PSFCH resources) to transmit the control information. In a third implementation, the one or more SAs may transmit the control information via the S-UCI resources without transmitting via the PSFCH resources. In a fourth implementation, the one or more SAs may receiving a configuration message indicating the resources (the S-UCI resources or the PSFCH resources) for transmitting the control information. In a fifth implementation, the one or more SAs may transmit the control information via the PSFCH resources. 
     In some aspects of the present disclosure, the BS or the PLC may schedule S-DCI resources and PSFCH resources for the downlink transmission of control information by the PLC. In a first implementation, the PLC may transmit the control information to the one or more SAs via the PSFCH resources if the one or more SAs are legacy sidelink devices. In a second implementation, the PLC may transmit the control information via the S-DCI resources and the PSFCH resources. In a third implementation, the PLC may choose the earliest resources (of the S-DCI resources and the PSFCH resources) to transmit the control information. In a fourth implementation, the PLC may transmit the control information via the S-DCI resources without transmitting via the PSFCH resources. 
     In certain aspects of the present disclosure, the PLC may ignore PSFCH and return HARQ via second-stage sidelink control information (SCI- 2 ). The PLC may toggle a new data indicator of the SCI- 2  to indicate retransmission in the same slot. 
     An example of sidelink communication may include cellular vehicle to everything (CV2X) applications. To receive sidelink packets, the receiver (RX) may perform blind decoding in some or all sub-channels. The number of sub-channels may range from, e.g., 1-27 channels. Physical sidelink control channel (PSCCH) and physical sidelink shared channel (PSSCH) may be transmitted within a same slot. PSSCH may occupy up to N subchannel   SL  contiguous sub-channels. PSCCH may occupy one sub-channel with the lowest sub-channel index. The first-stage SCI (SCI- 1 ) may be transmitted in PSCCH containing information about PSSCH bandwidth and resource reservation in future slots. The second-stage SCI (SCI- 2 ) may be found and decoded after decoding PSCCH. The source identification (ID) and/or destination ID may be used to identify the transmitting UE and the receiving UE of the packet, respectively. The size of the sub-channels in vehicle to everything (V2X) may be 10 or more resource blocks (RBs). In CV2X, the UEs may decode all transmissions and blind decode all sub-channels. 
     The SCI  1 _ 0  in PSCCH, the frequency domain resource allocation (FDRA) may allocate 
     
       
         
           
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     bits for 3 reservations. The time domain allocation (TDRA) may allocate 5 bits for 2 reservations and 9 bits for 3 reservations. 
     In some implementations, PSCCH may be configured or preconfigured to occupy, 10, 12, 15, 20, 25 or other number of RBs, which may be limited to a single sub-channel. PSCCH duration may be configured or preconfigured to 2 or 3 symbols. A sub-channel may occupy 10, 12, 15, 20, 25 or other number of RBs. The number of sub-channels may be 1-27, for example, in a resource pool (RP). PSCCH size may be fixed for a resource pool, such as 10% to 100% of a sub-channel (first 2 or 3 symbols), depending on the configuration. PSSCH may occupy at least 1 sub-channel and/or contain SCI- 2 . 
     In CV2X, there may be two methods of resource allocation. In mode 1, the BS (such as a gNB) assigns transmit (TX) resources for sidelink communications through downlink control information, such as DCI 3_0. In mode 2, the transmitting UE may autonomously determine the resources for sidelink communications. The receiving device may behave similarly in mode 1 and mode 2. 
     In some implementations, mode 1 may support dynamic grants (DG), configured grants (CG) type 1, and CG type 2. CG type 1 may be activated via radio resource control (RRC) signaling from the BS. DCI 3_0 may be transmitted by the BS to allocate time and frequency resources and indicate transmission timing. The modulation and coding scheme (MCS) may be up to the UE within a limit set by the BS. 
     In an implementation, during mode 2, the transmitting UE may perform channel sensing by blindly decoding some or all PSCCH channels and identify reserved resources by other sidelink transmissions (if any). The transmitting UE may report available resources to upper layer and the upper layer may decide resource usage. 
     In some instances of industrial internet of things (IoT), sidelink may enable direct programmable logical controller and sensor/actuator communications. A wireless PLC may be flexible and allow for simple deployment. Each PLC may control a number of SAs, such as 20-50 SAs as an example. Such a scheme may satisfy a tight latency (e.g., 1-2 milliseconds (ms)) and ultra-reliability requirement (e.g., 10 −6  error rate). Communication through one or more BSs may require multiple over the air (OTAs) transmissions, which may negatively impact latency and/or reliability. 
     Some example traffic characteristics of industrial IoT may be as follows: IoT traffic may typically be deterministic and/or with small packet size (e.g., 32-256 bytes). Since the required bandwidth is low, 2 RBs may be sufficient in some cases. The SAs may have constraints on UE capabilities in terms of bandwidth and processing power. The overall bandwidth may be large (e.g., 100 Megahertz or above) for IoT with dedicated frequency bands and/or unlicensed bands. The SAs may not need to detect and/or monitor all transmissions. PSCCH may be required to meet stringent IoT requirements. The radio frequency (RF) environment may include blockage and/or interference. 
     In some aspects of the present disclosure, SCI- 1  in sidelink (e.g., SCI  1 -A in PSSCH) may include bits for various fields, such as priority, frequency resource assignment, time resource assignment, resource reservation, reference signals/patterns, SCI- 2  format, reference signal port, MCS, and/or reserved bits. For example, the SCI- 1  may include 3 bits for priority. For frequency resource assignment, the number of bits may depend on the number of slot reservations and/or the number of sub-channels. For time resource assignment, 5 bits may be allocated for 2 reservations and 9 bits may be allocated for 3 reservations. During the resource reservation period, the number of bits may depend on the number of allowed periods. For the demodulation reference signal (DMRS) pattern, the number of bits may depend on the number of configured patterns. For SCI- 2  format, 2 bits may be allocated. The beta offset for SCI- 2  rate matching may include 2 bits. For DMRS port, a 1-bit field may indicate one or two data layers. For MCS, 5 bits may be used. For additional MCS table, 0-2 bits may be used. PSFCH overhead indicator may include 0 or 1 bit. Additional reserved bits may also be implemented for the upper layer. SCI- 1  may be decoded by the intended receiving device and/or other sidelink UEs (e.g., in mode 2) to allow channel sensing and avoid resource collision. 
     In some aspects of the present disclosure, SCI- 2  in sidelink (e.g., in PSSCH) may be front-loaded. The SCI- 2  may include bits for various fields such as NDI, HARQ ID, source ID, destination ID, HARQ enable/disable, redundancy version, cast type, channel state information/request, zone ID, and/or communication range. The number of bits for HARQ ID may depend on the number of HARQ processes. The SCI- 2  may include 1 bit for NDI. The SCI- 2  may include 2 bits for the redundancy version identifier (RV-ID). The SCI- 2  may include 8 bits for the source ID. The SCI- 2  may include 16 bits for the destination ID. The SCI- 2  may include 1 bit to indicate HARQ enable/disable. In some implementations, SCI  2 -A may include 2 bits to indicate cast type (e.g., broadcast, groupcast, unicast, etc.). The SCI  2 -A may include 1 bit for channel state information (CSI) request. In some implementations, SCI  2 -B may include 12 bits for the zone ID. The SCI  2 -B may include 4 bits for the communication range. In an implementation, the SCI- 2  may be intended for the receiving UE to decode PSSCH. 
       FIG. 1  is a diagram illustrating an example of a wireless communications system and an access network  100 . The wireless communications system (also referred to as a wireless wide area network (WWAN)) includes at least one BS  105 , UEs  110 , an Evolved Packet Core (EPC)  160 , and a 5G Core (5GC)  190 . The BS  105  may include macro cells (high power cellular base station) and/or small cells (low power cellular base station). The macro cells include base stations. The small cells include femtocells, picocells, and microcells. In one implementation, the UE  110  may include a communication component  222  configured to communicate with other UEs  110  via a sidelink communication network, a cellular network, a Wi-Fi network, or other wireless and wired networks. The UE  110  may include a scheduling component  224  for determining and/or identifying resources. The UE  110  may include a determination component  226  that determines the times of resources allocated (which resource is earlier). In some implementations, the communication component  222 , the scheduling component  224 , and/or the determination component  226  may be implemented using hardware, software, or a combination of hardware and software. In some implementations, the BS  105  may include a communication component  322  configured to communicate with the UE  110 . The BS  105  may include a scheduling component  324  configured to allocate resources to UEs  110  for sidelink communication during mode 1. In some implementations, the communication component  322  and/or the scheduling component  324  may be implemented using hardware, software, or a combination of hardware and software. 
     A BS  105  configured for 4G Long-Term Evolution (LTE) (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC  160  through backhaul links interfaces  132  (e.g., S1, X2, Internet Protocol (IP), or flex interfaces). A BS  105  configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN)) may interface with 5GC  190  through backhaul links interfaces  134  (e.g., S1, X2, Internet Protocol (IP), or flex interface). In addition to other functions, the BS  105  may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The BS  105  may communicate directly or indirectly (e.g., through the EPC  160  or 5GC  190 ) with each other over the backhaul links interfaces  134 . The backhaul links  132 ,  134  may be wired or wireless. 
     The BS  105  may wirelessly communicate with the UEs  110 . Each of the BS  105  may provide communication coverage for a respective geographic coverage area  130 . There may be overlapping geographic coverage areas  130 . For example, the small cell  105 ′ may have a coverage area  130 ′ that overlaps the coverage area  130  of one or more macro BS  105 . A network that includes both small cell and macro cells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs), which may provide service to a restricted group known as a closed subscriber group (CSG). The communication links  120  between the BS  105  and the UEs  110  may include uplink (UL) (also referred to as reverse link) transmissions from a UE  110  to a BS  105  and/or downlink (DL) (also referred to as forward link) transmissions from a BS  105  to a UE  110 . The communication links  120  may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The BS  105 /UEs  110  may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Y x  MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL). The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell). 
     Certain UEs  110  may communicate with each other using device-to-device (D2D) communication link  158 . The D2D communication link  158  may use the DL/UL WWAN spectrum. The D2D communication link  158  may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR. 
     The wireless communications system may further include a Wi-Fi access point (AP)  150  in communication with Wi-Fi stations (STAs)  152  via communication links  154  in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs  152 /AP  150  may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available. 
     The small cell  105 ′ may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell  105 ′ may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP  150 . The small cell  105 ′, employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network. 
     A BS  105 , whether a small cell  105 ′ or a large cell (e.g., macro base station), may include an eNB, gNodeB (gNB), or other type of base station. Some base stations, such as gNB  180  may operate in one or more frequency bands within the electromagnetic spectrum. The electromagnetic spectrum is often subdivided, based on frequency/wavelength, into various classes, bands, channels, etc. In 5G NR two initial operating bands have been identified as frequency range designations FR 1  (410 MHz-7.125 GHz) and FR 2  (24.25 GHz-52.6 GHz). The frequencies between FR 1  and FR 2  are often referred to as mid-band frequencies. Although a portion of FR 1  is greater than 6 GHz, FR 1  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 FR 2 , which is often referred to (interchangeably) as a “millimeter wave” (mmW) 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. 
     With the above aspects 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 FR 1 , 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 FR 2 , or may be within the EHF band. Communications using the mmW/near mmW radio frequency band has extremely high path loss and a short range. The mmW base station  180  may utilize beamforming  182  with the UE  110  to compensate for the path loss and short range. 
     The EPC  160  may include a Mobility Management Entity (MME)  162 , other MMEs  164 , a Serving Gateway  166 , a Multimedia Broadcast Multicast Service (MBMS) Gateway  168 , a Broadcast Multicast Service Center (BM-SC)  170 , and a Packet Data Network (PDN) Gateway  172 . The MME  162  may be in communication with a Home Subscriber Server (HSS)  174 . The MME  162  is the control node that processes the signaling between the UEs  110  and the EPC  160 . Generally, the MME  162  provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway  166 , which itself is connected to the PDN Gateway  172 . The PDN Gateway  172  provides UE IP address allocation as well as other functions. The PDN Gateway  172  and the BM-SC  170  are connected to the IP Services  176 . The IP Services  176  may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a packet switched (PS) Streaming Service, and/or other IP services. The BM-SC  170  may provide functions for MBMS user service provisioning and delivery. The BM-SC  170  may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS Gateway  168  may be used to distribute MBMS traffic to the BS  105  belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information. 
     The 5GC  190  may include a Access and Mobility Management Function (AMF)  192 , other AMFs  193 , a Session Management Function (SMF)  194 , and a User Plane Function (UPF)  195 . The AMF  192  may be in communication with a Unified Data Management (UDM)  196 . The AMF  192  is the control node that processes the signaling between the UEs  110  and the 5GC  190 . Generally, the AMF  192  provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF  195 . The UPF  195  provides UE IP address allocation as well as other functions. The UPF  195  is connected to the IP Services  197 . The IP Services  197  may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, and/or other IP services. 
     The BS  105  may also be referred to as a gNB, Node B, evolved Node B (eNB), an access point, a base transceiver station, a radio base station, an access point, an access node, a radio transceiver, a NodeB, eNodeB (eNB), gNB, Home NodeB, a Home eNodeB, a relay, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit reception point (TRP), or some other suitable terminology. The BS  105  provides an access point to the EPC  160  or 5GC  190  for a UE  110 . Examples of UEs  110  include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs  110  may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc.). The UE  110  may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. 
     Referring to  FIG. 2 , one example of an implementation of the UE  110  may include a modem  220  having the communication component  222 , the scheduling component  224 , and/or the determination component  226 . In one implementation, the UE  110  may include a communication component  222  configured to communicate with other UEs  110  via a sidelink communication network, a cellular network, a Wi-Fi network, or other wireless and wired networks. The UE  110  may include a scheduling component  224  for determining and/or identifying resources. The UE  110  may include a determination component  226  that determines the times of resources allocated (which resource is earlier). 
     In some implementations, the UE  110  may include a variety of components, including components such as one or more processors  212  and memory  216  and transceiver  202  in communication via one or more buses  244 , which may operate in conjunction with the modem  220  and the communication component  222  to enable one or more of the functions described herein related to communicating with the BS  105 . Further, the one or more processors  212 , modem  220 , memory  216 , transceiver  202 , RF front end  288  and one or more antennas  265 , may be configured to support voice and/or data calls (simultaneously or non-simultaneously) in one or more radio access technologies. The one or more antennas  265  may include one or more antennas, antenna elements and/or antenna arrays. 
     In an aspect, the one or more processors  212  may include the modem  220  that uses one or more modem processors. The various functions related to the communication component  222 , the scheduling component  224 , and/or the determination component  226  may be included in the modem  220  and/or processors  212  and, in an aspect, may be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors  212  may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiving device processor, or a transceiver processor associated with transceiver  202 . Additionally, the modem  220  may configure the UE  110  along with the processors  212 . In other aspects, some of the features of the one or more processors  212  and/or the modem  220  associated with the communication component  222  may be performed by transceiver  202 . 
     The memory  216  may be configured to store data used and/or local versions of application  275 . Also, the memory  216  may be configured to store data used herein and/or local versions of the communication component  222 , the scheduling component  224 , and/or the determination component  226 , and/or one or more of the subcomponents being executed by at least one processor  212 . Memory  216  may include any type of computer-readable medium usable by a computer or at least one processor  212 , such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory  216  may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining the communication component  222 , the scheduling component  224 , and/or the determination component  226 , and/or one or more of the subcomponents, and/or data associated therewith, when UE  110  is operating at least one processor  212  to execute the communication component  222 , the scheduling component  224 , and/or the determination component  226 , and/or one or more of the subcomponents. 
     Transceiver  202  may include at least one receiver  206  and at least one transmitter  208 . Receiver  206  may include hardware, firmware, and/or software code executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). Receiver  206  may be, for example, a RF receiving device. In an aspect, the receiver  206  may receive signals transmitted by at least one BS  105 . Transmitter  208  may include hardware, firmware, and/or software code executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). A suitable example of transmitter  208  may including, but is not limited to, an RF transmitter. 
     Moreover, in an aspect, UE  110  may include RF front end  288 , which may operate in communication with one or more antennas  265  and transceiver  202  for receiving and transmitting radio transmissions, for example, wireless communications transmitted by at least one BS  105  or wireless transmissions transmitted by UE  110 . RF front end  288  may be coupled with one or more antennas  265  and may include one or more low-noise amplifiers (LNAs)  290 , one or more switches  292 , one or more power amplifiers (PAs)  298 , and one or more filters  296  for transmitting and receiving RF signals. 
     In an aspect, LNA  290  may amplify a received signal at a desired output level. In an aspect, each LNA  290  may have a specified minimum and maximum gain values. In an aspect, RF front end  288  may use one or more switches  292  to select a particular LNA  290  and the specified gain value based on a desired gain value for a particular application. 
     Further, for example, one or more PA(s)  298  may be used by RF front end  288  to amplify a signal for an RF output at a desired output power level. In an aspect, each PA  298  may have specified minimum and maximum gain values. In an aspect, RF front end  288  may use one or more switches  292  to select a particular PA  298  and the specified gain value based on a desired gain value for a particular application. 
     Also, for example, one or more filters  296  may be used by RF front end  288  to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, a respective filter  296  may be used to filter an output from a respective PA  298  to produce an output signal for transmission. In an aspect, each filter  296  may be coupled with a specific LNA  290  and/or PA  298 . In an aspect, RF front end  288  may use one or more switches  292  to select a transmit or receive path using a specified filter  296 , LNA  290 , and/or PA  298 , based on a configuration as specified by transceiver  202  and/or processor  212 . 
     As such, transceiver  202  may be configured to transmit and receive wireless signals through one or more antennas  265  via RF front end  288 . In an aspect, transceiver may be tuned to operate at specified frequencies such that UE  110  may communicate with, for example, one or more BS  105  or one or more cells associated with one or more BS  105 . In an aspect, for example, the modem  220  may configure transceiver  202  to operate at a specified frequency and power level based on the UE configuration of the UE  110  and the communication protocol used by the modem  220 . 
     In an aspect, the modem  220  may be a multiband-multimode modem, which may process digital data and communicate with transceiver  202  such that the digital data is sent and received using transceiver  202 . In an aspect, the modem  220  may be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, the modem  220  may be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, the modem  220  may control one or more components of UE  110  (e.g., RF front end  288 , transceiver  202 ) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In an aspect, the modem configuration may be based on the mode of the modem and the frequency band in use. In another aspect, the modem configuration may be based on UE configuration information associated with UE  110  as provided by the network. 
     Referring to  FIG. 3 , one example of an implementation of the BS  105  may include a modem  320  having the communication component  322  and/or the scheduling component  324 . In some implementations, the BS  105  may include a communication component  322  configured to communicate with the UE  110 . The BS  105  may include a scheduling component  324  configured to allocate resources to UEs  110  for sidelink communication during mode 1. 
     In some implementations, the BS  105  may include a variety of components, including components such as one or more processors  312  and memory  316  and transceiver  302  in communication via one or more buses  344 , which may operate in conjunction with the modem  320  and the communication component  322  to enable one or more of the functions described herein related to communicating with the UE  110 . Further, the one or more processors  312 , modem  320 , memory  316 , transceiver  302 , RF front end  388  and one or more antennas  365 , may be configured to support voice and/or data calls (simultaneously or non-simultaneously) in one or more radio access technologies. 
     In an aspect, the one or more processors  312  may include the modem  320  that uses one or more modem processors. The various functions related to the communication component  322  and/or the scheduling component  324  may be included in the modem  320  and/or processors  312  and, in an aspect, may be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors  312  may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiving device processor, or a transceiver processor associated with transceiver  302 . Additionally, the modem  320  may configure the BS  105  and processors  312 . In other aspects, some of the features of the one or more processors  312  and/or the modem  320  associated with the communication component  322  may be performed by transceiver  302 . 
     The memory  316  may be configured to store data used herein and/or local versions of applications  375 . Also, the memory  316  may be configured to store data used herein and/or local versions of the communication component  322  and/or the scheduling component  324 , and/or one or more of the subcomponents being executed by at least one processor  312 . Memory  316  may include any type of computer-readable medium usable by a computer or at least one processor  312 , such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory  316  may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining the communication component  322  and/or the scheduling component  324 , and/or one or more of the subcomponents, and/or data associated therewith, when the BS  105  is operating at least one processor  312  to execute the communication component  322  and/or the scheduling component  324 , and/or one or more of the subcomponents. 
     Transceiver  302  may include at least one receiver  306  and at least one transmitter  308 . The at least one receiver  306  may include hardware, firmware, and/or software code executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). The receiver  306  may be, for example, a RF receiving device. In an aspect, receiver  306  may receive signals transmitted by the UE  110 . Transmitter  308  may include hardware, firmware, and/or software code executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). A suitable example of transmitter  308  may including, but is not limited to, an RF transmitter. 
     Moreover, in an aspect, the BS  105  may include RF front end  388 , which may operate in communication with one or more antennas  365  and transceiver  302  for receiving and transmitting radio transmissions, for example, wireless communications transmitted by other BS  105  or wireless transmissions transmitted by UE  110 . RF front end  388  may be coupled with one or more antennas  365  and may include one or more low-noise amplifiers (LNAs)  390 , one or more switches  392 , one or more power amplifiers (PAs)  398 , and one or more filters  396  for transmitting and receiving RF signals. 
     In an aspect, LNA  390  may amplify a received signal at a desired output level. In an aspect, each LNA  390  may have a specified minimum and maximum gain values. In an aspect, RF front end  388  may use one or more switches  392  to select a particular LNA  390  and the specified gain value based on a desired gain value for a particular application. 
     Further, for example, one or more PA(s)  398  may be used by RF front end  388  to amplify a signal for an RF output at a desired output power level. In an aspect, each PA  398  may have specified minimum and maximum gain values. In an aspect, RF front end  388  may use one or more switches  392  to select a particular PA  398  and the specified gain value based on a desired gain value for a particular application. 
     Also, for example, one or more filters  396  may be used by RF front end  388  to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, a respective filter  396  may be used to filter an output from a respective PA  398  to produce an output signal for transmission. In an aspect, each filter  396  may be coupled with a specific LNA  390  and/or PA  398 . In an aspect, RF front end  388  may use one or more switches  392  to select a transmit or receive path using a specified filter  396 , LNA  390 , and/or PA  398 , based on a configuration as specified by transceiver  302  and/or processor  312 . 
     As such, transceiver  302  may be configured to transmit and receive wireless signals through one or more antennas  365  via RF front end  388 . In an aspect, transceiver may be tuned to operate at specified frequencies such that BS  105  may communicate with, for example, the UE  110  or one or more cells associated with one or more BS  105 . In an aspect, for example, the modem  320  may configure transceiver  302  to operate at a specified frequency and power level based on the base station configuration of the BS  105  and the communication protocol used by the modem  320 . 
     In an aspect, the modem  320  may be a multiband-multimode modem, which may process digital data and communicate with transceiver  302  such that the digital data is sent and received using transceiver  302 . In an aspect, the modem  320  may be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, the modem  320  may be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, the modem  320  may control one or more components of the BS  105  (e.g., RF front end  388 , transceiver  302 ) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In an aspect, the modem configuration may be based on the mode of the modem and the frequency band in use. In another aspect, the modem configuration may be based on base station configuration associated with the BS  105 . 
       FIG. 4  illustrates an example of an environment  400  of wireless communication between devices based on sidelink communications, such as V2X/V2V/D2D communications. For example, PLC  402  (also known as an anchor) may transmit a transmission  414 , e.g., comprising a control channel and/or a corresponding data channel, that may be received by SAs  404 ,  406 ,  408  (also known as clients). A control channel may include information for decoding a data channel and may also be used by a receiving device to avoid interference by refraining from transmitting on the occupied resources during a data transmission. The number of transmission time intervals (TTIs), as well as the RBs that will be occupied by the data transmission, may be indicated in a control message from the transmitting device. The PLC  402  and/or the SAs  404 ,  406 ,  408  may each be capable of operating as a transmitting device in addition to operating as a receiving device. Thus, SAs  406 ,  408  are illustrated as transmitting transmissions  416 ,  420 . The transmissions  414 ,  416 ,  420  may be broadcasted or multicasted to nearby devices. For example, PLC  402  may transmit communication intended for receipt by other UEs within a range  401  of PLC  402 . Additionally/alternatively, a roadside unit (RSU)  407  may receive communication from and/or transmit communication to the PLC  402  and/or the SAs  404 ,  406 ,  408 . 
     The PLC  402 , the SAs  404 ,  406 ,  408 , and/or RSU  407  may include one or more of the communication component  222 , the scheduling component  224 , and/or the determination component  226 . 
       FIG. 5  illustrates an example diagram of NR sidelink physical layer structure  500 . In NR sidelink design, PSCCH carries sidelink control information (SCI) among wireless devices. The associated PSSCH carries data information. In NR, PSCCH and PSSCH may be time domain multiplexed. The first symbol in the slot is the automatic gain control (AGC)  510  for pre-process the control and/or data information and/or to normalize the incoming signal power. The last symbol is the gap symbol  520  (guard symbol). 
       FIG. 6  illustrates an example of resources used for sidelink communication. In an implementation, resources  600  for sidelink communication may include PSCCH  610  allocated for the exchange of control information between UEs  110  during sidelink communication. The resources  600  may include PSSCH  620  allocated for data information. The resources  600  may include a gap  630  delimiting the resources  600  from neighboring resources. 
       FIG. 7  illustrates an example of overlapping S-UCI and PSFCH resources. In certain implementations, and referencing  FIG. 4 , resources  700  for transmitting sidelink control information (SCI) may include a first slot  710  and a second slot  720 . The resources  700  may be allocated by the BS  105  (e.g., via the scheduling component  324 ) and/or the PLC  402  (e.g., via the scheduling component  224 ), depending on the mode. The first slot  710  may be allocated for downlink transmission. The PLC  402  may transmit downlink information (control and/or data) to one or more of the SAs  404 ,  406 ,  408  via resources in the first slot  710 , such as the SA  406 . The SA  406  may “listen” for downlink information in the first slot. The second slot  720  may be allocated for uplink transmission. The SA  406  may transmit uplink information (control and/or data) to the PLC  402  or other SAs via resources in the second slot  720 . Examples of control information may include one or more of a resource selection, a collision detection, a channel state information (CSI) report, a HARQ acknowledgement, a HARQ negative acknowledgement, or a scheduling request (SR). 
     In some instances, the resources  700  may include a PSSCH+SCI portion  730  that includes resources (e.g., resource blocks) for PSSCH. The PSSCH+SCI portion  730  may include first-stage SCI (SCI- 1 )  740  and second-stage SCI (SCI- 2 )  750 . As discussed above, the SCI- 1   740  may include one or more bits for indicating priority, frequency resource assignment, time resource assignment, resource reservation period, DMRS pattern, SCI- 2  format, beta offset, DMRS port, MCS, PSFCH overhead, and/or reserved. The SCI- 2   750  may include one or more bits for indicating HARQ ID, NDI, RVID, source ID, destination ID, HARQ enable/disable, cast type, CSI request, zone ID, and/or communication range. 
     In some implementations, the resources  700  may be allocated for sidelink downlink control information (S-DCI)  760 . The resources  700  may be allocated for sidelink uplink control information (S-UCI)  770 . The resources  700  may be allocated for PSFCH  780 . The resources for the S-UCI  770  may overlap with the resources for the PSFCH  780  because they are being allocated in the same slot, namely the second slot  720 , and/or the same symbol. The BS  105  and/or the PLC  402  may allocate the resources for the S-UCI  770  and/or the PSFCH  780  for uplink transmission of control information by the SA  406 . The SA  406  may receive scheduling information indicating the resources for the S-UCI  770  and the PSFCH  780  allocated by the BS  105 . The SA  406  may transmit the uplink control information via at least one of the S-UCI  770  and/or the PSFCH  780 . 
     In a first aspect of the present disclosure, the SA  406  may transmit the uplink control information via the S-UCI  770  and the PSFCH  780 . The PSFCH  780  may offer an additional opportunity for the PLC  402  to receive and/or decode the control information. The PLC  402  may monitor one or both of the S-UCI  770  and the PSFCH  780 . By transmitting the uplink control information via the S-UCI  770  and the PSFCH  780 , diversity gain may be achieved (e.g., for HARQ report). 
     In a second aspect of the present disclosure, the SA  406  may determine (e.g., via the determination component  226 ) an earliest resource among the S-UCI  770  and the PSFCH  780 . The SA  406  may transmit the uplink control information via the earliest resource to reduce latency. The SA  406  may refrain from transmitting the uplink control information via later resources. For example, the SA  406  may determine that a first S-UCI resource  771  is the earliest resource. The first S-UCI resource  771  may be temporally allocated earlier than a second S-UCI resource  772  and the PSFCH  780 . As a result, the SA  406  may transmit the uplink control information in the first S-UCI resource  771  only, and refrain from transmitting the uplink control information in the second S-UCI resource  772  and/or the PSFCH  780 . 
     In a third aspect of the present disclosure, the SA  406  may transmit the uplink control information via the S-UCI  770  and refrain from transmitting the control information via the PSFCH  780 . The SA  406  may multiplex the uplink control information. The SA  406  may transmit the uplink control information via the S-UCI  770  to receivers (i.e., PLC  402 ) configured to receive control information via S-UCI resources. 
     In a fourth aspect of the present disclosure, the PLC  402  may transmit (e.g., via the communication component  222 ) an indicator indicating to the SA  406  which resource(s) to use for the uplink control information. The indication may indicate to the SA  406  to transmit the uplink control information via the S-UCI  770 , the PSFCH  780 , or both. The indication may be transmitted in S-DCI or an upper layer signaling. The PLC  402  may determine resource(s) for the transmission of the control information based on the sidelink communication channel latency and/or the priority requirement of the traffic/control information. 
     In a fifth aspect of present disclosure, the PLC  402  may schedule the PSFCH  780  along with the S-UCI  770 . The PLC  402  may schedule the SA  404  to use the PSFCH for transmitting the uplink control information. The PSFCH  780  may be an extension of the S-UCI  770 . 
       FIG. 8  illustrates an example of overlapping S-DCI and PSFCH resources. In certain implementations, and referencing  FIG. 4 , resources  800  for transmitting SCI may include a first slot  810  and a second slot  820 . The resources  800  may be allocated by the BS  105  (e.g., via the scheduling component  324 ) and/or the PLC  402  (e.g., via the scheduling component  224 ), depending on the mode. The first slot  810  may be allocated for downlink transmission. The PLC  402  may transmit downlink information (control and/or data) to one or more of the SAs  404 ,  406 ,  408  via resources in the first slot  810 , such as the SA  406 . The SA  406  may “listen” for downlink information in the resources  800 . The second slot  820  may be allocated for uplink transmission. The SA  406  may transmit uplink information (control and/or data) to the PLC  402  or other SAs via resources in the second slot  820 . Examples of control information may include one or more of a resource selection, a collision detection, a channel state information (CSI) report, a HARQ acknowledgement, a HARQ negative acknowledgement, or a scheduling request (SR). 
     In some instances, the resources  800  may include a PSSCH+SCI portion  830  that includes resources (e.g., resource blocks) for PSSCH. The PSSCH+SCI portion  830  may include first-stage SCI (SCI- 1 )  840  and second-stage SCI (SCI- 2 )  850 . As discussed above, the SCI- 1   840  may include one or more bits for indicating priority, frequency resource assignment, time resource assignment, resource reservation period, DMRS pattern, SCI- 2  format, beta offset, DMRS port, MCS, PSFCH overhead, and/or reserved. The SCI- 2   850  may include one or more bits for indicating HARQ ID, NDI, RVID, source ID, destination ID, HARQ enable/disable, cast type, CSI request, zone ID, and/or communication range. 
     In some implementations, the resources  800  may include sidelink downlink control information (S-DCI)  860 . The resources  800  may include sidelink uplink control information (S-UCI)  870 . The resources  800  may include PSFCH  880 . The resources for the S-DCI  860  may overlap with the resources for the PSFCH  880  because they are being allocated in the same slot, namely the first slot  810 , and/or the same symbol. The BS  105  and/or the PLC  402  may allocate the resources for the S-DCI  860  and/or the PSFCH  880  for downlink transmission of control information by the PLC  402 . The PLC  402  may receive scheduling information indicating the resources for the S-DCI  860  and the PSFCH  880  allocated by the BS  105 . The PLC  402  may transmit the downlink control information via at least one of the S-DCI  860  and/or the PSFCH  880 . 
     In a first aspect of the present disclosure, the PLC  402  may transmit the downlink control information via the PSFCH  880 . This scheme may be suitable for legacy SAs unable to receive and/or decode S-DCI. 
     In a second aspect of the present disclosure, the PLC  402  may transmit the downlink control information via the S-DCI  860  and the PSFCH  880 . The PSFCH  880  may offer an additional opportunity for the SA  406  to receive and/or decode the control information. The SA  406  may monitor one or both of the S-UCI resources  870  and the PSFCH  880 . By transmitting the uplink control information via the S-DCI  860  and the PSFCH  880 , diversity gain may be achieved (e.g., for HARQ report). 
     In a third aspect of the present disclosure, the PLC  402  may determine (e.g., via the determination component  226 ) an earliest resource among the S-DCI  860  and the PSFCH  880 . The PLC  402  may transmit the downlink control information via the earliest resource to reduce latency. The SA  406  may refrain from transmitting the downlink control information via later resources. For example, the PLC  402  may determine that a first S-DCI resource  861  and/or a second S-DCI resource  862  are the earliest resources. The first S-DCI resource  861  and the second S-DCI resource  862  may be temporally allocated earlier than the remaining resources of the S-DCI  860  and the PSFCH  880 . As a result, the PLC  402  may transmit the downlink control information in the first S-DCI resource  861  and/or the second S-DCI only, and refrain from transmitting the downlink control information in the remaining resources of the S-DCI  860  and/or the PSFCH  880 . 
     In a fourth aspect of the present disclosure, the PLC  402  may transmit the downlink control information via the S-DCI  860  and refrain from transmitting the control information via the PSFCH  880 . The PLC  402  may multiplex the downlink control information. The PLC  402  may transmit the uplink control information via the S-DCI  860  to receivers (e.g., SAs  404 ,  406 ,  408 ) configured to receive control information via S-DCI  860 . The S-DCI  860  may include more advanced coding. The S-DCI  860  may include error correction. 
     In a fifth aspect of the present disclosure, the PLC  402  may refrain from transmitting the control information via the S-DCI  860  or the PSFCH  880 . The PLC  402  may return HARQ via SCI- 2  NDI for the same HARQ-ID. The PLC  402  may toggle the NDI for the HARQ-ID if the SCI- 2   850  transmission occurs (if the PLC  402  has traffic to the SA  406  in the first slot  810 ). For example, the PLC  402  may transmit the SCI- 1   840  in the first slot  810 . Next, the PLC  402  may transmit the SCI- 2   850  in the same slot (i.e., the first slot  810 ). The SCI- 2   850  may include a NDI value (e.g., not toggled) indicating the retransmission of a previous PSSCH. The current aspect may be used for Uu transmission interface. 
       FIG. 9  is an example of a method for transmitting uplink sidelink control information. For example, a method  900  may be performed by the one or more of the processor  212 , the memory  216 , the applications  275 , the modem  220 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the communication component  222 , the scheduling component  224 , and/or the determination component  226 , and/or one or more other components of the UE  110  in the wireless communication network  100 . 
     At block  905 , the method  900  may receive first scheduling information indicating a sidelink uplink control information (S-UCI) resource. For example, the communication component  222 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the subcomponents of the RF front end  288 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  of the UE  110  may receive first scheduling information indicating a sidelink uplink control information (S-UCI) resource as described above. The RF front end  288  may receive the electrical signals converted from electro-magnetic signals. The RF front end  288  may filter and/or amplify the electrical signals. The transceiver  202  or the receiver  206  may convert the electrical signals to digital signals, and send the digital signals to the communication component  222 . 
     In certain implementations, the communication component  222 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the subcomponents of the RF front end  288 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  may be configured to and/or may define means for receiving first scheduling information indicating a sidelink uplink control information (S-UCI) resource. 
     At block  910 , the method  900  may receive second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource. For example, the communication component  222 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the subcomponents of the RF front end  288 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  of the UE  110  may receive second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource as described above. The RF front end  288  may receive the electrical signals converted from electro-magnetic signals. The RF front end  288  may filter and/or amplify the electrical signals. The transceiver  202  or the receiver  206  may convert the electrical signals to digital signals, and send the digital signals to the communication component  222 . 
     In certain implementations, the communication component  222 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the subcomponents of the RF front end  288 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  may be configured to and/or may define means for receiving second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource. 
     At block  915 , the method  900  may transmit control information via at least one of the S-UCI resource or the one or more PSFCH resources. For example, the communication component  222 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the subcomponents of the RF front end  288 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  of the UE  110  may transmit control information via at least one of the S-UCI resource or the one or more PSFCH resources. The communication component  222  may send the digital signals to the transceiver  202  or the transmitter  208 . The transceiver  202  or the transmitter  208  may convert the digital signals to electrical signals and send to the RF front end  288 . The RF front end  288  may filter and/or amplify the electrical signals. The RF front end  288  may send the electrical signals as electro-magnetic signals via the one or more antennas  265 . 
     In certain implementations, the communication component  222 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the subcomponents of the RF front end  288 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  may be configured to and/or may define means for transmitting control information via at least one of the S-UCI resource or the one or more PSFCH resources. 
     Alternatively or additionally, the method  900  may further include any of the methods above, wherein transmitting the control information comprises transmitting the control information via the S-UCI resource and the one or more PSFCH resources. 
     Alternatively or additionally, the method  900  may further include any of the methods above, further comprising determining an earlier resource of the S-UCI resource and the one or more PSFCH resources, and wherein transmitting the control information comprises: transmitting the control information via the earlier resource, and refraining from transmitting the control information in the other resource. 
     Alternatively or additionally, the method  900  may further include any of the methods above, wherein transmitting the control information comprises transmitting the control information via the S-UCI resource, wherein the control information includes S-UCI bits and PSFCH bits, and refraining from transmitting the control information in the one or more PSFCH resources. 
     Alternatively or additionally, the method  900  may further include any of the methods above, further comprising receiving, prior to transmitting the control information, an indication indicating transmission of the control information via the S-UCI resource or the one or more PSFCH resources, and wherein transmitting the control information comprises transmitting the control information based on the indication. 
     Alternatively or additionally, the method  900  may further include any of the methods above, further comprising receiving an indication indicating transmission of the control information via a PSFCH resource of the one or more PSFCH resources, and wherein transmitting the control information comprises transmitting the control information via the PSFCH resource. 
     Alternatively or additionally, the method  900  may further include any of the methods above, wherein the control information includes at least one of a resource selection, a collision detection, a channel state information (CSI) report, a hybrid automatic repeat request (HARQ) acknowledgement, a HARQ negative acknowledgement, or a scheduling request. 
       FIG. 10  is an example of a method for transmitting downlink sidelink control information. For example, a method  1000  may be performed by the one or more of the processor  212 , the memory  216 , the applications  275 , the modem  220 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the communication component  222 , the scheduling component  224 , and/or the determination component  226 , and/or one or more other components of the UE  110  in the wireless communication network  100 . 
     At block  1005 , the method  1000  may identify first scheduling information indicating a sidelink downlink control information (S-DCI) resource. For example, the scheduling component  224 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  of the UE  110  may identify first scheduling information indicating a sidelink downlink control information (S-DCI) resource as described above. 
     In certain implementations, the scheduling component  224 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  may be configured to and/or may define means for identifying first scheduling information indicating a sidelink downlink control information (S-DCI) resource. 
     At block  1010 , the method  1000  may identify second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource. For example, the scheduling component  224 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  of the UE  110  may identify second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource as described above. 
     In certain implementations, the scheduling component  224 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  may be configured to and/or may define means for identifying second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource. 
     At block  1015 , the method  1000  may transmit control information via at least one of the S-DCI resource or the one or more PSFCH resources. For example, the communication component  222 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the subcomponents of the RF front end  288 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  of the UE  110  may transmit control information via at least one of the S-DCI resource or the one or more PSFCH resources. The communication component  222  may send the digital signals to the transceiver  202  or the transmitter  204 . The transceiver  202  or the transmitter  204  may convert the digital signals to electrical signals and send to the RF front end  288 . The RF front end  288  may filter and/or amplify the electrical signals. The RF front end  288  may send the electrical signals as electro-magnetic signals via the one or more antennas  265 . 
     In certain implementations, the communication component  222 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the subcomponents of the RF front end  288 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  may be configured to and/or may define means for transmitting control information via at least one of the S-DCI resource or the one or more PSFCH resources. 
     Alternatively or additionally, the method  1000  may further include any of the methods above, wherein transmitting the control information comprises transmitting the control information to a sidelink device via the one or more PSFCH resources. 
     Alternatively or additionally, the method  1000  may further include any of the methods above, wherein transmitting the control information comprises transmitting the control information to a sidelink device via the S-DCI resource and the one or more PSFCH resources. 
     Alternatively or additionally, the method  1000  may further include any of the methods above, further comprising determining an earlier resource of the S-DCI resource and the one or more PSFCH resources, and wherein transmitting the control information comprises: transmitting the control information via the earlier resource, and refraining from transmitting the control information in the other resource. 
     Alternatively or additionally, the method  1000  may further include any of the methods above, wherein transmitting the control information comprises transmitting the control information via the S-DCI resource, wherein the control information includes S-DCI bits and PSFCH bits, and refraining from transmitting the control information in the one or more PSFCH resources. 
     Alternatively or additionally, the method  1000  may further include any of the methods above, wherein the control information includes at least one of a resource selection, a collision detection, a channel state information (CSI) report, a hybrid automatic repeat request (HARQ) acknowledgement, a HARQ negative acknowledgement, or a scheduling request. 
       FIG. 11  is an example of a method for transmitting sidelink control information. For example, a method  1100  may be performed by the one or more of the processor  212 , the memory  216 , the applications  275 , the modem  220 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the communication component  222 , the scheduling component  224 , and/or the determination component  226 , and/or one or more other components of the UE  110  in the wireless communication network  100 . 
     At block  1105 , the method  1100  may transmit first-stage sidelink control information (SCI- 1 ) in a first resource. For example, the communication component  222 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the subcomponents of the RF front end  288 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  of the UE  110  may transmit first-stage sidelink control information (SCI- 1 ) in a first resource. The communication component  222  may send the digital signals to the transceiver  202  or the transmitter  204 . The transceiver  202  or the transmitter  204  may convert the digital signals to electrical signals and send to the RF front end  288 . The RF front end  288  may filter and/or amplify the electrical signals. The RF front end  288  may send the electrical signals as electro-magnetic signals via the one or more antennas  265 . 
     In certain implementations, the communication component  222 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the subcomponents of the RF front end  288 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  may be configured to and/or may define means for transmitting first-stage sidelink control information (SCI- 1 ) in a first resource. 
     At block  1110 , the method  1100  may transmit second-stage sidelink control information (SCI- 2 ), after transmitting the SCI- 1 , in a second resource, wherein the SCI- 2  includes a new data indicator (NDI) value indicating a retransmission of a previous physical sidelink shared channel (PSSCH). For example, the communication component  222 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the subcomponents of the RF front end  288 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  of the UE  110  may transmit second-stage sidelink control information (SCI- 2 ), after transmitting the SCI- 1 , in a second resource, wherein the SCI- 2  includes a new data indicator (NDI) value indicating a retransmission of a previous physical sidelink shared channel (PSSCH). The communication component  222  may send the digital signals to the transceiver  202  or the transmitter  204 . The transceiver  202  or the transmitter  204  may convert the digital signals to electrical signals and send to the RF front end  288 . The RF front end  288  may filter and/or amplify the electrical signals. The RF front end  288  may send the electrical signals as electro-magnetic signals via the one or more antennas  265 . 
     In certain implementations, the communication component  222 , the transceiver  202 , the receiver  206 , the transmitter  208 , the RF front end  288 , the subcomponents of the RF front end  288 , the processor  212 , the memory  216 , the modem  220 , and/or the applications  275  may be configured to and/or may define means for transmitting second-stage sidelink control information (SCI- 2 ), after transmitting the SCI- 1 , in a second resource, wherein the SCI- 2  includes a new data indicator (NDI) value indicating a retransmission of a previous physical sidelink shared channel (PSSCH). 
     Additional Implementations 
     Aspects of the present disclosure include methods by a user equipment (UE) for receiving first scheduling information indicating a sidelink uplink control information (S-UCI) resource, receiving second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and transmitting control information via at least one of the S-UCI resource or the one or more PSFCH resources. 
     Any of the methods above, wherein transmitting the control information comprises transmitting the control information via the S-UCI resource and the one or more PSFCH resources. 
     Any of the methods above, further comprising determining an earlier resource of the S-UCI resource and the one or more PSFCH resources, and wherein transmitting the control information comprises: transmitting the control information via the earlier resource, and refraining from transmitting the control information in the other resource. 
     Any of the methods above, wherein transmitting the control information comprises transmitting the control information via the S-UCI resource, wherein the control information includes S-UCI bits and PSFCH bits, and refraining from transmitting the control information in the one or more PSFCH resources. 
     Any of the methods above, further comprising receiving, prior to transmitting the control information, an indication indicating transmission of the control information via the S-UCI resource or the one or more PSFCH resources, and wherein transmitting the control information comprises transmitting the control information based on the indication. 
     Any of the methods above, further comprising receiving an indication indicating transmission of the control information via a PSFCH resource of the one or more PSFCH resources, and wherein transmitting the control information comprises transmitting the control information via the PSFCH resource. 
     Any of the methods above, wherein the control information includes at least one of a resource selection, a collision detection, a channel state information (CSI) report, a hybrid automatic repeat request (HARQ) acknowledgement, a HARQ negative acknowledgement, or a scheduling request. 
     Other aspects of the present disclosure include a user equipment (UE) having a memory comprising instructions, a transceiver, and one or more processors operatively coupled with the memory and the transceiver, the one or more processors configured to execute instructions in the memory to receive, via the transceiver, first scheduling information indicating a sidelink uplink control information (S-UCI) resource, receive, via the transceiver, second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and transmit, via the transceiver, control information via at least one of the S-UCI resource or the one or more PSFCH resources. 
     Any of the UEs above, wherein transmitting the control information comprises transmitting, via the transceiver, the control information via the S-UCI resource and the one or more PSFCH resources. 
     Any of the UEs above, wherein the one or more processors are further configured to determine an earlier resource of the S-UCI resource and the one or more PSFCH resources, and wherein transmitting the control information comprises: transmitting, via the transceiver, the control information via the earlier resource, and refraining from transmitting the control information in the other resource. 
     Any of the UEs above, wherein transmitting the control information comprises transmitting, via the transceiver, the control information via the S-UCI resource, wherein the control information includes S-UCI bits and PSFCH bits, and refraining from transmitting the control information in the one or more PSFCH resources. 
     Any of the UEs above, wherein the one or more processors are further configured to receive, via the transceiver, prior to transmitting the control information, an indication indicating transmission of the control information via the S-UCI resource or the one or more PSFCH resources, and wherein transmitting the control information comprises transmitting the control information based on the indication. 
     Any of the UEs above, wherein the one or more processors are further configured to receive, via the transceiver, an indication indicating transmission of the control information via a PSFCH resource of the one or more PSFCH resources, and wherein transmitting the control information comprises transmitting, via the transceiver, the control information via the PSFCH resource. 
     Any of the UEs above, wherein the control information includes at least one of a resource selection, a collision detection, a channel state information (CSI) report, a hybrid automatic repeat request (HARQ) acknowledgement, a HARQ negative acknowledgement, or a scheduling request. 
     An aspect of the present disclosure includes a user equipment (UE) including means for receiving first scheduling information indicating a sidelink uplink control information (S-UCI) resource, means for receiving second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and means for transmitting control information via at least one of the S-UCI resource or the one or more PSFCH resources. 
     Any of the UEs above, wherein means for transmitting the control information comprises means for transmitting the control information via the S-UCI resource and the one or more PSFCH resources. 
     Any of the UEs above, wherein means for transmitting the control information comprises means for determining an earlier resource of the S-UCI resource and the one or more PSFCH resources, and wherein means for transmitting the control information comprises: means for transmitting the control information via the earlier resource, and means for refraining from transmitting the control information in the other resource. 
     Any of the UEs above, wherein means for transmitting the control information comprises means for transmitting the control information via the S-UCI resource, wherein the control information includes S-UCI bits and PSFCH bits, and means for refraining from transmitting the control information in the one or more PSFCH resources. 
     Any of the UEs above, further comprising means for receiving, prior to transmitting the control information, an indication indicating transmission of the control information via the S-UCI resource or the one or more PSFCH resources, and wherein means for transmitting the control information comprises means for transmitting the control information based on the indication. 
     Any of the UEs above, further comprising means for receiving an indication indicating transmission of the control information via a PSFCH resource of the one or more PSFCH resources, and wherein means for transmitting the control information comprises means for transmitting the control information via the PSFCH resource. 
     Any of the UEs above, wherein the control information includes at least one of a resource selection, a collision detection, a channel state information (CSI) report, a hybrid automatic repeat request (HARQ) acknowledgement, a HARQ negative acknowledgement, or a scheduling request. 
     Some aspects of the present disclosure include non-transitory computer readable media having instructions stored therein that, when executed by one or more processors of a user equipment (UE), cause the one or more processors to receive first scheduling information indicating a sidelink uplink control information (S-UCI) resource, receive second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and transmit control information via at least one of the S-UCI resource or the one or more PSFCH resources. 
     Any of the non-transitory computer readable media above, wherein the instructions for transmitting the control information further comprising instructions for transmitting the control information via the S-UCI resource and the one or more PSFCH resources. 
     Any of the non-transitory computer readable media above, further comprising instructions, when executed by the one or more processors, cause the one or more processors to determine an earlier resource of the S-UCI resource and the one or more PSFCH resources, and wherein transmitting the control information comprises: transmitting the control information via the earlier resource, and refraining from transmitting the control information in the other resource 
     Any of the non-transitory computer readable media above, wherein the instructions for transmitting the control information further comprising instructions for transmitting the control information via the S-UCI resource, wherein the control information includes S-UCI bits and PSFCH bits, and refraining from transmitting the control information in the one or more PSFCH resources. 
     Any of the non-transitory computer readable media above, further comprising instructions, when executed by the one or more processors, cause the one or more processors to receive, prior to transmitting the control information, an indication indicating transmission of the control information via the S-UCI resource or the one or more PSFCH resources, and wherein transmitting the control information comprises transmitting the control information based on the indication. 
     Any of the non-transitory computer readable media above, further comprising instructions, when executed by the one or more processors, cause the one or more processors to receive an indication indicating transmission of the control information via a PSFCH resource of the one or more PSFCH resources, and wherein transmitting the control information comprises transmitting the control information via the PSFCH resource. 
     Any of the non-transitory computer readable media above, wherein the control information includes at least one of a resource selection, a collision detection, a channel state information (CSI) report, a hybrid automatic repeat request (HARQ) acknowledgement, a HARQ negative acknowledgement, or a scheduling request. 
     Aspects of the present disclosure include methods by a user equipment (UE) for identifying first scheduling information indicating a sidelink downlink control information (S-DCI) resource, identifying second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and transmitting control information via at least one of the S-DCI resource or the one or more PSFCH resources. 
     Any of the methods above, wherein transmitting the control information comprises transmitting the control information to a sidelink device via the one or more PSFCH resources. 
     Any of the methods above, wherein transmitting the control information comprises transmitting the control information to a sidelink device via the S-DCI resource and the one or more PSFCH resources. 
     Any of the methods above, further comprising determining an earlier resource of the S-DCI resource and the one or more PSFCH resources, and wherein transmitting the control information comprises: transmitting the control information via the earlier resource, refraining from transmitting the control information in the other resource. 
     Any of the methods above, wherein transmitting the control information comprises transmitting the control information via the S-DCI resource, wherein the control information includes S-DCI bits and PSFCH bits, and refraining from transmitting the control information in the one or more PSFCH resources. 
     Any of the methods above, wherein the control information includes at least one of a resource selection, a collision detection, a channel state information (CSI) report, a hybrid automatic repeat request (HARQ) acknowledgement, a HARQ negative acknowledgement, or a scheduling request. 
     Other aspects of the present disclosure include a user equipment (UE) having a memory comprising instructions, a transceiver, and one or more processors operatively coupled with the memory and the transceiver, the one or more processors configured to execute instructions in the memory to identify first scheduling information indicating a sidelink downlink control information (S-DCI) resource, identify second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and transmit, via the transceiver, control information via at least one of the S-DCI resource or the one or more PSFCH resources. 
     Any of the UEs above, wherein transmitting the control information comprises transmitting, via the transceiver, the control information to a sidelink device via the one or more PSFCH resources. 
     Any of the UEs above, wherein transmitting the control information comprises transmitting, via the transceiver, the control information to a sidelink device via the S-DCI resource and the one or more PSFCH resources. 
     Any of the UEs above, wherein the one or more processors are further configured to determine an earlier resource of the S-DCI resource and the one or more PSFCH resources, and wherein transmitting the control information comprises: transmitting, via the transceiver, the control information via the earlier resource, and refraining from transmitting the control information in the other resource. 
     Any of the UEs above, wherein transmitting the control information comprises transmitting, via the transceiver, the control information via the S-DCI resource, wherein the control information includes S-DCI bits and PSFCH bits, and refraining from transmitting the control information in the one or more PSFCH resources. 
     Any of the UEs above, wherein the control information includes at least one of a resource selection, a collision detection, a channel state information (CSI) report, a hybrid automatic repeat request (HARQ) acknowledgement, a HARQ negative acknowledgement, or a scheduling request. 
     An aspect of the present disclosure includes a user equipment (UE) including means for identifying first scheduling information indicating a sidelink downlink control information (S-DCI) resource, means for identifying second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and means for transmitting control information via at least one of the S-DCI resource or the one or more PSFCH resources. 
     Any of the UEs above, wherein means for transmitting the control information comprises means for transmitting the control information to a sidelink device via the one or more PSFCH resources. 
     Any of the UEs above, wherein means for transmitting the control information comprises means for transmitting the control information to a sidelink device via the S-DCI resource and the one or more PSFCH resources. 
     Any of the UEs above, further comprising means for determining an earlier resource of the S-DCI resource and the one or more PSFCH resources, and wherein means for transmitting the control information comprises: means for transmitting the control information via the earlier resource, and means for refraining from transmitting the control information in the other resource. 
     Any of the UEs above, wherein means for transmitting the control information comprises means for transmitting the control information via the S-DCI resource, wherein the control information includes S-DCI bits and PSFCH bits, and means for refraining from transmitting the control information in the one or more PSFCH resources. 
     Any of the UEs above, wherein the control information includes at least one of a resource selection, a collision detection, a channel state information (CSI) report, a hybrid automatic repeat request (HARQ) acknowledgement, a HARQ negative acknowledgement, or a scheduling request. 
     Some aspects of the present disclosure include non-transitory computer readable media having instructions stored therein that, when executed by one or more processors of a user equipment (UE), cause the one or more processors to identify first scheduling information indicating a sidelink downlink control information (S-DCI) resource, identify second scheduling information indicating one or more physical sidelink feedback channel (PSFCH) resource, and transmit control information via at least one of the S-DCI resource or the one or more PSFCH resources. 
     Any of the non-transitory computer readable media above, wherein the instructions for transmitting the control information further comprising instructions for transmitting the control information to a sidelink device via the one or more PSFCH resources. 
     Any of the non-transitory computer readable media above, wherein the instructions for transmitting the control information further comprising instructions for transmitting the control information to a sidelink device via the S-DCI resource and the one or more PSFCH resources. 
     Any of the non-transitory computer readable media above, further comprising instructions, when executed by the one or more processors, cause the one or more processors to determine an earlier resource of the S-DCI resource and the one or more PSFCH resources, and wherein transmitting the control information comprises: transmitting the control information via the earlier resource, and refraining from transmitting the control information in the other resource. 
     Any of the non-transitory computer readable media above, wherein the instructions for transmitting the control information further comprising instructions for transmitting the control information via the S-DCI resource, wherein the control information includes S-DCI bits and PSFCH bits, and refraining from transmitting the control information in the one or more PSFCH resources. 
     Any of the non-transitory computer readable media above, wherein the control information includes at least one of a resource selection, a collision detection, a channel state information (CSI) report, a hybrid automatic repeat request (HARQ) acknowledgement, a HARQ negative acknowledgement, or a scheduling request. 
     Aspects of the present disclosure include methods by a user equipment (UE) for transmitting first-stage sidelink control information (SCI- 1 ) in a first resource and transmitting second-stage sidelink control information (SCI- 2 ), after transmitting the SCI- 1 , in a second resource, wherein the SCI- 2  includes a new data indicator (NDI) value indicating that the SCI- 2  is a retransmission of the SCI- 1 . 
     Other aspects of the present disclosure include a user equipment (UE) having a memory comprising instructions, a transceiver, and one or more processors operatively coupled with the memory and the transceiver, the one or more processors configured to execute instructions in the memory to transmit, via the transceiver, first-stage sidelink control information (SCI- 1 ) in a first resource and transmit, via the transceiver, second-stage sidelink control information (SCI- 2 ), after transmitting the SCI- 1 , in a second resource, wherein the SCI- 2  includes a new data indicator (NDI) value indicating that the SCI- 2  is a retransmission of the SCI- 1 . 
     An aspect of the present disclosure includes a user equipment (UE) including means for transmitting first-stage sidelink control information (SCI- 1 ) in a first resource and means for transmitting second-stage sidelink control information (SCI- 2 ), after transmitting the SCI- 1 , in a second resource, wherein the SCI- 2  includes a new data indicator (NDI) value indicating that the SCI- 2  is a retransmission of the SCI- 1 . 
     Some aspects of the present disclosure include non-transitory computer readable media having instructions stored therein that, when executed by one or more processors of a user equipment (UE), cause the one or more processors to transmit first-stage sidelink control information (SCI- 1 ) in a first resource and transmit second-stage sidelink control information (SCI- 2 ), after transmitting the SCI- 1 , in a second resource, wherein the SCI- 2  includes a new data indicator (NDI) value indicating that the SCI- 2  is a retransmission of the SCI- 1 . 
     The above detailed description set forth above in connection with the appended drawings describes examples and does not represent the only examples that may be implemented or that are within the scope of the claims. The term “example,” when used in this description, means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. For example, changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Also, various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in other examples. In some instances, well-known structures and apparatuses are shown in block diagram form in order to avoid obscuring the concepts of the described examples. 
     It should be noted that the techniques described herein may be used for various wireless communication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms “system” and “network” are often used interchangeably. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0 and A are commonly referred to as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1×EV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM™, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP LTE and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies, including cellular (e.g., LTE) communications over a shared radio frequency spectrum band. The description herein, however, describes an LTE/LTE-A system or 5G system for purposes of example, and LTE terminology is used in much of the description below, although the techniques may be applicable other next generation communication systems. 
     Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, computer-executable code or instructions stored on a computer-readable medium, or any combination thereof. 
     The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a specially-programmed device, such as but not limited to a processor, a digital signal processor (DSP), an ASIC, a FPGA or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination thereof designed to perform the functions described herein. A specially-programmed processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A specially-programmed processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a non-transitory computer-readable medium. Other examples and implementations are within the scope and spirit of the disclosure and appended claims. For example, due to the nature of software, functions described above may be implemented using software executed by a specially programmed processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Also, as used herein, including in the claims, “or” as used in a list of items prefaced by “at least one of” indicates a disjunctive list such that, for example, a list of “at least one of A, B, or C” means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). 
     Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage medium may be any available medium that may be accessed by a general purpose or special purpose computer. By way of example, and not limitation, computer-readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media. 
     The previous description of the disclosure is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the common principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Furthermore, although elements of the described aspects may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. Additionally, all or a portion of any aspect may be utilized with all or a portion of any other aspect, unless stated otherwise. Thus, the disclosure is not to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.