WO2023227991A1

WO2023227991A1 - Power control for sidelink transmission

Info

Publication number: WO2023227991A1
Application number: PCT/IB2023/054892
Authority: WO
Inventors: Joachim Löhr; Karthikeyan Ganesan; Prateek Basu Mallick; Ravi Kuchibhotla
Original assignee: Lenovo (Singapore) Pte. Ltd.
Priority date: 2022-05-24
Filing date: 2023-05-11
Publication date: 2023-11-30

Abstract

Various aspects of the present disclosure relate to a UE that adapts sidelink transmissions to UE power constraints. For instance, power scaling is described which utilizes transmission parameters such as sidelink transmission priority and/or QoS parameters for configuring sidelink transmissions. Further, UE information reporting mechanisms are provided for reporting sidelink-related information.

Description

POWER CONTROL FOR SIDELINK TRANSMISSION RELATED APPLICATION [0001] This application claims priority to U.S. Patent Application Serial No.63/345,351 filed 24 May 2022 entitled “POWER CONTROL FOR SIDELINK TRANSMISSION,” the disclosure of which is incorporated by reference herein in its entirety. TECHNICAL FIELD ^[0002] The present disclosure relates to wireless communications, and more specifically to power control in wireless communications. BACKGROUND [0003] A wireless communications system may include one or multiple network communication devices, such as base stations, which may be otherwise known as an eNodeB (eNB), a next-generation NodeB (gNB), or other suitable terminology. Each network communication device, such as a base station, may support wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (UE), or other suitable terminology. The wireless communications system may support wireless communications with one or multiple user communication devices by utilizing resources of the wireless communication system, such as time resources (e.g., symbols, slots, subslots, mini-slots, aggregated slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers). Additionally, the wireless communications system may support wireless communications across various radio access technologies (RATs) including third generation (3G) RAT, fourth generation (4G) RAT, fifth generation (5G) RAT, and other suitable RATs beyond 5G. In some cases, a wireless communications system may be a non- terrestrial network (NTN), which may support various communication devices for wireless communications in the NTN. For example, an NTN may include network entities onboard non-terrestrial vehicles such as satellites, unmanned aerial vehicles (UAV), and high-altitude platforms systems (HAPS), as well as network entities on the ground, such as gateway entities capable of transmitting and receiving over long distances. [0004] UEs can be subject to limitations on transmit power, such as based on UE-specific power specifications and/or safety-related power limitations, e.g., specific absorption rate (SAR) and maximum permissible exposure (MPE) limits. Such power limitations can affect a UEs ability to meet certain transmission specifications such as quality of service (QoS) specifications for certain types of transmissions. SUMMARY ^[0005] The present disclosure relates to methods, apparatuses, and systems that support power control for sidelink transmission. By utilizing the described techniques, a UE can adapt sidelink transmissions to UE power constraints. For instance, power scaling is described which observes transmission parameters such as sidelink transmission priority and/or QoS parameters for sidelink transmissions. Further, UE information reporting mechanisms are provided for reporting sidelink-related information. For instance, a UE can report sidelink- related path loss information and/or power headroom information to a network (e.g., a gNB), such as to enable the network to avoid scheduling sidelink resources for the UE that may exceed available power resources of the UE. [0006] Some implementations of the methods and apparatuses described herein may include wireless communication at an apparatus (e.g., a UE), and the apparatus determines that a total transmit power for a set of sidelink transmissions on a group of sidelink carriers exceeds a maximum transmit power of the UE; orders sidelink transmissions of the set of sidelink transmissions into a priority order based at least in part on at least one criteria; and adjusts a transmit power of at least a first sidelink transmission of the set of sidelink transmissions based on the priority order such that a total transmit power for the set of sidelink transmissions is equal to or smaller than the maximum transmit power. ^[0007] In some implementations of the methods and apparatuses described herein, the apparatus groups the sidelink transmissions of the set of sidelink transmissions into sidelink channel groups, and to order the sidelink transmissions includes to order the sidelink channel groups based at least in part on the at least one criteria; a first group of the sidelink channel groups includes at least one physical sidelink feedback channel (PSFCH); the first group of the sidelink channel groups including the at least one PSFCH has a highest transmission priority of the group of sidelink channels; a first group of the sidelink channel groups includes at least one physical sidelink control channel (PSCCH); a first group of the sidelink channel group includes at least one physical sidelink shared channel (PSSCH); to adjust the transmit power of the at least first sidelink transmission, the apparatus causes the UE to first adjust the transmit power of at least one PSSCH that does not include a sidelink media access control (MAC) control element (CE). ^[0008] In some implementations of the methods and apparatuses described herein, a first group of the sidelink channel group includes at least one PSSCH that includes sidelink control information; the sidelink control information is signaled within a MAC CE; to adjust the transmit power of the at least first sidelink transmission of the set of sidelink transmissions, the apparatus scales the transmit power of the at least first sidelink transmission to zero before a transmit power of a second sidelink transmission of a higher priority than the first sidelink transmission is reduced; to adjust the transmit power of the at least first sidelink transmission of the set of sidelink transmissions, the apparatus scales the transmit power of the at least first sidelink transmission to a minimum transmit power for the at least firm sidelink transmission before a transmit power of a second sidelink transmission of a higher priority than the first sidelink transmission is reduced; to order the sidelink transmissions, the apparatus prioritizes a second sidelink transmission over the at least first sidelink transmission based at least in part on the second sidelink transmission having a higher priority than the at least first sidelink transmission; and to adjust the transmit power of the at least first sidelink transmission, the apparatus reduces the transmit power of the at least first sidelink transmission based at least in part on the at least first sidelink transmission having a lower priority than the second sidelink transmission. [0009] In some implementations of the methods and apparatuses described herein, the total transmit power for the set of sidelink transmissions on the group of sidelink carriers includes a sum of individual sidelink transmissions of the set of sidelink transmissions; the apparatus compares the adjusted transmit power of the at least first sidelink transmission to a predefined power threshold; the apparatus does not perform the at least first sidelink transmission when the adjusted transmit power of the at least first sidelink transmission is below the predefined power threshold; when the UE does not perform the at least first sidelink transmission, the apparatus transmits, to a network device, an indication that the at least first sidelink transmission was not performed based at least in part on the adjusted transmit power of the at least first sidelink transmission being below the predefined power threshold; when the UE does not perform the at least first sidelink transmission, the apparatus triggers a reselection of at least one sidelink resource for the at least first sidelink transmission by the UE; the at least one criteria includes a prioritization of transmissions by the UE, and the prioritization includes, from highest priority and descending in priority: PSFCH transmission, PSCCH transmission with sidelink control information (SCI), PSSCH transmission with sidelink MAC CE transmission, and PSCCH transmissions without MAC CE. ^[0010] In some implementations of the methods and apparatuses described herein, the at least one criteria includes a minimum communication range (MCR), a second sidelink transmission of the set of sidelink transmissions includes an MCR value, and to order sidelink transmissions, the apparatus prioritizes the second sidelink transmission over the at least first sidelink transmission based at least in part on the at least first sidelink transmission having a lower MCR value than the second sidelink transmission, or the at least first sidelink transmission having no MCR value; the at least one criteria includes transmission cast type, a second sidelink transmission of the set of sidelink transmissions includes a unicast transmission, and to order sidelink transmissions, the apparatus prioritizes the second sidelink transmission over the at least first sidelink transmission based at least in part on the at least first sidelink transmission having a cast type other than unicast; the at least one criteria includes transmission destination priority, and to order sidelink transmissions, the apparatus prioritizes a second sidelink transmission over the at least first sidelink transmission based at least in part on the second sidelink transmission having a higher priority transmission destination than the at least first sidelink transmission; the at least one criteria includes transmission resource pool priority, and to order sidelink transmissions, the apparatus prioritizes a second sidelink transmission over the at least first sidelink transmission based at least in part on the second sidelink transmission being performed in a higher priority transmission resource pool than the at least first sidelink transmission. [0011] In some implementations of the methods and apparatuses described herein, the at least one criteria includes a transmission resource allocation mode, and to order sidelink transmissions, the apparatus prioritizes a second sidelink transmission over the at least first sidelink transmission based at least in part on the second sidelink transmission including a network allocated sidelink transmission and the at least first sidelink transmission including a UE allocated sidelink transmission; the at least first sidelink transmission is associated with a sidelink carrier of the group of sidelink carriers, the sidelink carrier is associated with a maximum carrier transmit power, and to adjust the transmit power of the at least first sidelink transmission, the apparatus reduces the transmit power of the at least first sidelink transmission until the transmit power of the at least first sidelink transmission is equal to or lesser than the maximum carrier transmit power. [0012] Some implementations of the methods and apparatuses described herein may include wireless communication at an apparatus (e.g., a UE), and the apparatus configures a path loss reference for at least one sidelink carrier of a set of sidelink carriers for carrier aggregation (CA) by the UE; determines, based at least in part on the path loss reference, a transmit power for transmission over the at least one sidelink carrier of the set of sidelink carriers; and transmits over the at least one sidelink carrier using the determined transmit power. [0013] In some implementations of the methods and apparatuses described herein, each sidelink carrier includes a respective path loss reference, and the path loss reference for the at least one sidelink carrier is configured individually for the at least one sidelink carrier; the path loss reference is configured as a common path loss reference for the set of sidelink carriers as a group; the path loss reference includes a downlink path loss reference; the path loss reference includes a sidelink path loss reference; the path loss reference is based on both a downlink path loss reference and a sidelink path loss reference. [0014] Some implementations of the methods and apparatuses described herein may include wireless communication at an apparatus (e.g., a UE), and the apparatus generates a power indication identifying a sidelink power headroom of the UE; transmits, to a network device, the power indication; and receives, from the network device, a sidelink resource allocation for sidelink transmission by the UE. [0015] In some implementations of the methods and apparatuses described herein, the power indication includes reference timing information that identifies sidelink resources used to calculate the sidelink power headroom; the power indication includes sidelink path loss information for sidelink path loss between the UE and a receiving UE; the apparatus generates the power indication based at least in part on CA operation of the UE; the apparatus generates the power indication based at least in part on a sidelink power reporting trigger; the sidelink power reporting trigger includes an indication of at least one of that a sidelink path loss changes more than a threshold, or that a downlink path loss changes more than a threshold; the apparatus transmits the power indication to the network device via a MAC CE. ^[0016] Some implementations of the methods and apparatuses described herein may include wireless communication at an apparatus (e.g., a network device such as a base station), and the apparatus generates a criteria indication indicating at least one criteria for ordering sidelink transmission by a UE; and transmits the criteria indication to the UE. [0017] In some implementations of the methods and apparatuses described herein, the criteria indication identifies transmission priorities for different types of sidelink transmissions; the at least one criteria includes a prioritization of transmissions by the UE, and the prioritization includes, from highest priority and descending in priority: PSFCH transmission, PSCCH transmission with SCI, PSCCH transmission with sidelink MAC CE transmission, and PSCCH transmissions with priority indicators; the at least one criteria includes an indication that a first sidelink transmission with a higher MCR value is to be prioritized over a second sidelink transmission with a lower MCR value or no MCR value; the at least one criteria includes one or more of: a transmission prioritization indication based on cast type; a transmission prioritization indication based on transmission destination priority; a transmission prioritization indication based on transmission resource pool priority; or a transmission prioritization indication based on transmission resource allocation mode; the apparatus receives, from the UE, an indication that a sidelink transmission was not performed based at least in part on an adjusted transmit power of the sidelink transmission being below a predefined power threshold; generates, based at least in part on the indication that the sidelink transmission was not performed, a resource indication including sidelink resources reselected for the UE; and transmits, to the UE, the resource indication. [0018] Some implementations of the methods and apparatuses described herein may include wireless communication at an apparatus (e.g., a network device such as a base station), and the apparatus receives, from a UE, a power indication indicating a sidelink power headroom of the UE; generates, based at least in part on the power indication, a sidelink resource allocation for the UE; and transmits the sidelink resource allocation to the UE. ^[0019] In some implementations of the methods and apparatuses described herein, the power indication includes reference timing information that identifies sidelink resources used to calculate the sidelink power headroom; the power indication includes sidelink path loss information for sidelink path loss between the UE and a different UE; the power indication is received via a MAC CE. BRIEF DESCRIPTION OF THE DRAWINGS [0020] Various aspects of the present disclosure for power control for sidelink transmission are described with reference to the following Figures. The same numbers may be used throughout to reference like features and components shown in the Figures. [0021] FIG. 1 illustrates an example of a wireless communications system that supports power control for sidelink transmission in accordance with aspects of the present disclosure. [0022] FIG. 2 illustrates an example block diagram of components of a device (e.g., a UE) that supports power control for sidelink transmission in accordance with aspects of the present disclosure. [0023] FIG. 3 illustrates an example block diagram of components of a device (e.g., a base station and/or other network device) that supports power control for sidelink transmission in accordance with aspects of the present disclosure. ^[0024] FIGs.4-10 illustrate flowcharts of methods that support power control for sidelink transmission in accordance with aspects of the present disclosure. DETAILED DESCRIPTION [0025] Implementations of power control for sidelink transmission are described, such as related to enabling a UE to adapt sidelink transmissions to UE power constraints. For instance, power scaling is described which utilizes transmission parameters such as sidelink transmission priority and/or QoS parameters for sidelink transmissions. Further, UE information reporting mechanisms are provided for reporting sidelink-related information. For instance, a UE can report sidelink-related path loss information and/or power headroom information to a network (e.g., gNB), such as to enable the network to avoid scheduling sidelink resources for the UE that exceed available power resources of the UE. [0026] In some wireless communications systems, when a UE is configured with sidelink CA and performing multiple sidelink transmissions on several sidelink carriers, the UE may exceed a maximum allowed transmit power. Further, when scaling down the transmit power of the individual sidelink transmissions, a UE may have difficulty complying with QoS parameters of some of the sidelink transmissions. Furthermore, some wireless communications systems do not provide power headroom reporting and/or path loss reporting for sidelink transmissions, which may result in situations where a sidelink resource scheduler doesn’t efficiently schedule sidelink resources for a transmit UE causing reduction in transmit signal quality and/or UE power limitations. [0027] Aspects of the disclosure include ways for enabling a UE to adapt sidelink transmissions to UE power constraints. For instance, power scaling is described which provides transmission parameters such as sidelink transmission priority and/or QoS parameters for sidelink transmissions. In implementations, some types of sidelink transmissions are prioritized over other types for purposes of power reduction. For instance, when a UE is to implement power reduction to enable compliance with power constraints, transmission power of lower priority sidelink transmissions can be reduced before other, higher priority sidelink transmissions. Further, UE power information reporting mechanisms are provided for reporting sidelink-related information. For instance, a UE can report sidelink path loss information and/or sidelink power headroom information to a network (e.g., gNB). Further, a UE can identify sidelink resources for which path loss and/or power headroom information was calculated. Based on the reported path loss information and/or power headroom information, a network can appropriately schedule sidelink resources to a UE. [0028] Accordingly, by enabling a UE to prioritize certain sidelink transmissions when subject to power constraints, signal quality (e.g., for QoS) of higher priority sidelink transmissions can be improved. Further, by providing sidelink-related power information for a UE to a network, the network can provide sidelink resources to the UE that correspond to available power resources of the UE. For instance, by providing sidelink-related power information for a UE, a network can avoid scheduling sidelink resources for the UE that exceed available power resources of the UE. ^[0029] Aspects of the present disclosure are described in the context of a wireless communications system. Aspects of the present disclosure are further illustrated and described with reference to device diagrams and flowcharts that relate to power control for sidelink transmission. [0030] FIG. 1 illustrates an example of a wireless communications system 100 that supports power control for sidelink transmission in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more base stations 102, one or more UEs 104, and a core network 106. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as an LTE network or an LTE- Advanced (LTE-A) network. In some other implementations, the wireless communications system 100 may be a 5G network, such as a NR network. In other implementations, the wireless communications system 100 may be a combination of a 4G network and a 5G network. The wireless communications system 100 may support radio access technologies beyond 5G. Additionally, the wireless communications system 100 may support technologies, such as time division multiple access (TDMA), frequency division multiple access (FDMA), or code division multiple access (CDMA), etc. ^[0031] The one or more base stations 102 may be dispersed throughout a geographic region to form the wireless communications system 100. One or more of the base stations 102 described herein may be, or include, or may be referred to as a base transceiver station, an access point, a NodeB, an eNodeB (eNB), a next-generation NodeB (gNB), a Radio Head (RH), a relay node, an integrated access and backhaul (IAB) node, or other suitable terminology. A base station 102 and a UE 104 may communicate via a communication link 108, which may be a wireless or wired connection. For example, a base station 102 and a UE 104 may perform wireless communication over a NR-Uu interface. [0032] A base station 102 may provide a geographic coverage area 110 for which the base station 102 may support services (e.g., voice, video, packet data, messaging, broadcast, etc.) for one or more UEs 104 within the geographic coverage area. For example, a base station 102 and a UE 104 may support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcast, etc.) according to one or multiple radio access technologies. In some implementations, a base station 102 may be moveable, such as when implemented as a gNB onboard a satellite or other non-terrestrial station (NTS) associated with a non-terrestrial network (NTN). In some implementations, different geographic coverage areas 110 associated with the same or different radio access technologies may overlap, and different geographic coverage areas 110 may be associated with different base stations 102. Information and signals described herein 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 description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. [0033] The one or more UEs 104 may be dispersed throughout a geographic region or coverage area 110 of the wireless communications system 100. A UE 104 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, a customer premise equipment (CPE), a subscriber device, or as some other suitable terminology. In some implementations, the UE 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, a UE 104 may be referred to as an Internet-of-Things (IoT) device, an Internet-of-Everything (IoE) device, or as a machine-type communication (MTC) device, among other examples. In some implementations, a UE 104 may be stationary in the wireless communications system 100. In other implementations, a UE 104 may be mobile in the wireless communications system 100, such as an earth station in motion (ESIM). [0034] The one or more UEs 104 may be devices in different forms or having different capabilities. Some examples of UEs 104 are illustrated in FIG. 1. A UE 104 may be capable of communicating with various types of devices, such as the base stations 102, other UEs 104, or network equipment (e.g., the core network 106, a relay device, a gateway device, an integrated access and backhaul (IAB) node, a location server that implements the location management function (LMF), or other network equipment). Additionally, or alternatively, a UE 104 may support communication with other base stations 102 or UEs 104, which may act as relays in the wireless communications system 100. [0035] A UE 104 may also support wireless communication directly with other UEs 104 over a communication link 112. For example, a UE 104 may support wireless communication directly with another UE 104 over a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular-V2X deployments, the communication link 112 may be referred to as a sidelink. For example, a UE 104 may support wireless communication directly with another UE 104 over a PC5 interface. [0036] A base station 102 may support communications with the core network 106, or with another base station 102, or both. For example, a base station 102 may interface with the core network 106 through one or more backhaul links 114 (e.g., via an S1, N2, or other network interface). The base stations 102 may communicate with each other over the backhaul links 114 (e.g., via an X2, Xn, or another network interface). In some implementations, the base stations 102 may communicate with each other directly (e.g., between the base stations 102). In some other implementations, the base stations 102 may communicate with each other indirectly (e.g., via the core network 106). In some implementations, one or more base stations 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC). The ANC may communicate with the one or more UEs 104 through one or more other access network transmission entities, which may be referred to as remote radio heads, smart radio heads, gateways, transmission-reception points (TRPs), and other network nodes and/or entities. [0037] The core network 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The core network 106 may be an evolved packet core (EPC), or a 5G core (5GC), which may include a control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management functions (AMF)), and a user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a Packet Data Network (PDN) gateway (P-GW), or a user plane function (UPF)). In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management for the one or more UEs 104 served by the one or more base stations 102 associated with the core network 106. [0038] According to implementations, one or more of the UEs 104 are operable to implement various aspects of power control for sidelink transmission as described herein. For instance, a UE 104a can implement power adjustment 116 operations to adjust power attributes of operation of the UE 104a, examples of which are detailed throughout this disclosure. The power adjustment 116, for example, adjusts power applied by the UE 104a as part of sidelink transmissions 118 to other UEs 104. In implementations, the sidelink transmissions 118 to UEs 104 can include sidelink transmission that implement CA. The power adjustment 116, for example, is based on a priority order of the sidelink transmissions 118. [0039] Further, the UE 104a and a base station 102 can transmit power notifications 120 to one another, such as further to aspects of power control for sidelink transmission. In implementations, for instance, a power notification 120 from the UE 104a to the base station 102 can include a sidelink power headroom report (PHR) of the UE 104a. Based on the PHR, the base station 102 can transmit a power notification 120 to the UE 104a including a sidelink resource allocation for sidelink transmission by the UE 104a. The base station 102 can also transmit power notifications 120 to the UE 104a that indicate sidelink ordering criteria for the UE 104a to order (e.g., prioritize) sidelink transmissions. [0040] In some wireless communications systems, sidelink communication was developed in radio access network (RAN) to support advanced V2X applications, such as for proximity-based service including public safety and commercial-related service. Further, power saving solutions (e.g., partial sensing, diversity receive (DRX)) and inter-UE coordination have been developed to improve power consumption for battery limited terminals and reliability of sidelink transmissions. Although NR sidelink was initially developed for V2X applications, there is growing interest in the industry to expand the applicability of NR sidelink to commercial use cases. For commercial sidelink applications, two key parameters have been identified: - Increased sidelink data rate - Support of new carrier frequencies for sidelink [0041] Increased sidelink data rate is motivated by applications such as sensor information (e.g., video) sharing between vehicles with high degree of driving automation. Commercial use cases could utilize data rates in excess of what is currently in use. Increased data rate can be achieved with the support of sidelink CA and sidelink over unlicensed spectrum. Furthermore, by enhancing the FR2 sidelink operation, increased data rate can be more efficiently supported on FR2. While the support of new carrier frequencies and larger bandwidths may allow improvement in data rate, this may also make sidelink more applicable for a wider range of applications. More specifically, with the support of unlicensed spectrum and the enhancement in FR2, sidelink may be in a better position to be implemented in commercial devices. [0042] Carrier aggregation can be a candidate solution for achieving higher data rate for sidelink application such as sensor information sharing between UEs (e.g., vehicles) with a high degree of driving automation. Carrier aggregation is a technique wherein multiple frequency portions (component carriers) are assigned to a same UE. A maximum available data rate per user is increased by increasing the number of component carriers available to a UE. A system data rate of a cell increases as well because of increased resource utilization. ^[0043] In NR V2X, sidelink power control is supported for PSCCH, PSSCH, PSFCH and sidelink synchronization signal block (S-SSB) transmissions. As transmission power control (TPC) commands may not be supported for NR V2X sidelink, the sidelink power control scheme may be open loop. For the sidelink power control, a maximum transmit power P_MAX can be configured at a transmit UE. Further, sidelink power control can be supported for unicast and groupcast transmissions in NR V2X. ^[0044] For unicast transmissions, the PSSCH power control can be configured to use the downlink path loss PL_DL (between the gNB and transmit UE) only, the sidelink path loss PLSL (between transmit UE and receive UE) only, or both downlink path loss PLDL and sidelink path loss PLSL. ^ The PSSCH power control can be based on the downlink path loss PL_DL when the transmit UE is in network coverage. This allows mitigating interference at the gNB. If the PSSCH power control is based on the downlink path loss only, transmit UEs near the gNB may transmit PSSCH at a lower power than transmit UEs farther away from the gNB. ^ The downlink path loss-based PSSCH power control can be enabled or disabled by the gNB. The downlink path loss can be derived at the transmit UE based on measurements of reference signals (e.g., channel state information reference signal (CSI-RS) or synchronization signal block (SSB)) sent by the gNB. ^ For unicast, the PSSCH power control can also be based on the sidelink path loss PLSL between the transmit UE and the receive UE. This allows compensating the attenuation in the sidelink channel. For instance, a transmit UE that is far away from the gNB may transmit PSSCH at a larger power than necessary when the PSSCH power control is configured to use downlink path loss only. o However, if the PSSCH power control takes the sidelink path loss also into account, this may avoid that a transmit UE transmits at a large power. The sidelink path loss-based PSSCH power control can be used when the transmit UE is in or out of network coverage. The sidelink path loss-based PSSCH power control can be enabled or disabled via (pre-)configuration. [0045] For this power control scheme, the transmit UE may need an estimate of the sidelink path loss that can be obtained from feedback of the receive UE. Based on PSSCH demodulation reference signal (DMRS) transmitted by the transmit UE, the receive UE can obtain an average reference signal receive power (RSRP) over several RSRP measurements to mitigate fluctuations on the received power [0046] Sidelink CA may not be efficient in all scenarios, e.g., where the data rate demand is low, when the UE capability does not allow sidelink-CA, or when the deployment and/or authorization does not allow sidelink CA to be used. Additionally, unlike Uu where the network knows the UE’s capability, in sidelink operation UEs may not know each other’s aggregation capabilities especially for groupcast and broadcast-based sidelink communication. For unicast sidelink communication, the capabilities may be shared when a PC5 radio resource control (RRC) Connection has been established between the peer UEs. [0047] In some wireless communications systems, a UE may equally scale down each of the multiple sidelink transmission for scenarios where the UE is power under a power constraint and configured with sidelink CA. This may lead to situations where the QoS parameters of individual sidelink transmission cannot be fulfilled. Furthermore, there is no power headroom reporting adopted in standards so far for sidelink transmissions, which may also result in situation where the sidelink scheduler doesn’t efficiently schedule a sidelink transmit UE, which may cause power limitations at a UE. [0048] For PSSCH, a UE can determine a power ^_PSSCH,^,^(^) for a PSSCH transmission on a resource pool in symbols where a corresponding PSCCH is not transmitted in PSCCH- PSSCH transmission occasion ^ on active sidelink bandwidth part (BWP) ^ of carrier ^ of serving cell ^ as:

where - is defined in [8-1, 3GPP technical specification (TS) 38.101-1]

- is determined by a value of sl-MaxTransPower based on a priority

level of the PSSCH transmission and a channel busy ratio (CBR) range that includes a CBR measured in slot i − N [6, TS 38.214]; if sl-MaxTransPower-r16 is not provided, then ;

-

- else -

where - - -

- the RS resource is the one the UE uses for determining a power of a physical uplink shared channel (PUSCH) transmission scheduled by a downlink control information (DCI) format 0_0 in serving cell ^ when the UE is configured to monitor a physical downlink control channel (PDCCH) for detection of DCI format 0_0 in serving cell ^ - the RS resource is the one corresponding to the synchronization signal physical broadcast channel (SS/PBCH) block the UE uses to obtain master information block (MIB) when the UE is not configured to monitor PDCCH for detection of DCI format 0_0 in serving cell ^ - is a number of resource blocks for the PSSCH transmission

occasion ^ and 5 is a subcarrier spacing (SCS) configuration - if sl-P0-PSSCH-PSCCH is provided and if a SCI format scheduling the PSSCH transmission includes a cast type indicator field indicating unicast -

- else -

where - - -

-

is obtained from a PSSCH transmit power per resource element (RE) summed over the antenna ports of the UE, higher layer filtered across PSSCH transmission occasions using a filter configuration provided by s , and

- , as defined in [7, TS 38.215], that

is reported to the UE from a UE receiving the PSCCH-PSSCH transmission and is obtained from a PSSCH DMRS using a filter configuration provided by sl- filterCoefficient - is a number of resource blocks for PSCCH-PSSCH transmission

occasion i and 5 is a SCS configuration [0049] A UE can split the power equally across the antenna ports on which the

UE transmits the PSSCH with non-zero power. A UE can determine a power

for a PSSCH transmission on a resource pool in the symbols where a corresponding PSCCH is transmitted in PSCCH-PSSCH transmission occasion ^ on active sidelink BWP b of carrier f of serving cell c as

where is a number of resource blocks for the corresponding PSCCH

transmission in PSCCH-PSSCH transmission occasion i. [^0050] The UE can split the power equally across the antenna ports on which

the UE transmits the PSSCH with non-zero power. [0051] For PSCCH, a UE can determine a power for a PSCCH transmission

on a resource pool in PSCCH-PSSCH transmission occasion ^ as

where -

- is a number of resource blocks for the PSCCH transmission in

PSCCH-PSSCH transmission occasion i - ) is a number of resource blocks for PSCCH-PSSCH transmission

occasion i [0052] For PSFCH, a UE with

scheduled PSFCH transmissions, and capable of transmitting a maximum of

can determine a number of simultaneous PSFCH transmissions and a power for a PSFCH

transmission on a resource pool in PSFCH transmission occasion i on

active sidelink BWP ^ of carrier f of serving cell c as -

is provided,

where - - -

- the RS resource is the one the UE uses for determining a power of a PUSCH transmission scheduled by a DCI format 0_0 in serving cell ^ when the UE is configured to monitor PDCCH for detection of DCI format 0_0 in serving cell i - the RS resource is the one corresponding to the SS/PBCH block the UE uses to obtain MIB when the UE is not configured to monitor PDCCH for detection of DCI format 0_0 in serving cell c

- the UE autonomously selects

PSFCH transmissions in ascending order of corresponding priority field values as described in clause 16.2.4.2 such that is a number of PSFCHs with priority value

^ and l is defined as - the largest value satisfying

is determined according to [8-1, TS 38.101-1] for transmission

of all PSFCHs assigned with priority values 1, 2, …, l, if any - zero, otherwise and

where is determined for the simultaneous PSFCH transmissions

according to [8-1, TS 38.101-1] - else

where the UE autonomously determines PSFCH transmissions with

ascending priority order as described in clause 16.2.4.2 such that

and where ^_CMAX is determined for the PSFCH transmissions according to [8-1, TS 38.101-

1] [0053] Accordingly, in some wireless communications systems, for scenarios where a UE is configured with sidelink CA and performing multiple sidelink transmissions on several sidelink carriers, a UE may exceed a maximum allowed transmit power, e.g., when the UE is under a transmit power constraint. For example, when scaling down the transmit power of individual sidelink transmissions, QoS parameters of some sidelink transmissions may not be met. Thus, this disclosure provides ways for providing an efficient UE behavior for scenarios where a UE is power constrained thereby considering QoS requirements of sidelink transmissions. [0054] In implementations, a transmit UE configured with multiple sidelink carriers and/or cells applies power reduction for the transmission of sidelink channels according to a predefined priority order, such as for scenarios where the UE is under a power constraint. For instance, for sidelink operation with CA, if a total UE transmit power for PSCCH or PSSCH or PSFCH transmissions on sidelink carriers and/or serving cells in a respective transmission occasion or slot i would exceed the maximum total transmit power of the UE, the UE allocates power to PSCCH, PSSCH, and/or PSFCH transmissions according to a priority order (e.g., in descending order) so that the total UE transmit power for transmissions on sidelink carriers and/or serving cells is smaller than or equal to maximum total transmit power (e.g. PSL-max) in each sidelink slot and/or symbol of a transmission occasion. ^[0055] A total UE transmit power in a symbol of a sidelink slot can be defined as the sum of the linear values of UE transmit powers for PSCCH, PSSCH, and/or PSFCH in the symbol of the slot. According to implementations, a priority order (in decreasing order staring with the highest priority) can be given as: - PSFCH transmission - PSCCH (SCI) - PSSCH transmissions which contain sidelink MAC CEs, e.g., CSI MAC CE, interconnect usage charge (IUC) report/request MAC CE, etc. - PSSCH transmission according to their priority, e.g., highest logical channel priority of multiplexed data or priority as indicated in the corresponding SCI [0056] In implementations, an MCR value associated with a PSCCH and/or PSSCH transmission on a sidelink carrier and/or cell is considered for the prioritization and power reduction rules when a UE is under a power constraint. MCR, for instance, is a QoS parameter introduced for 5G V2X which denotes that the QoS attributes like ultra-low latency and very high reliability requirement are to be fulfilled within a given MCR. In at least some example implementations, PSCCH and/or PSSCH transmission with a larger associated MCR value are prioritized over PSCCH and/or PSSCH transmission with a smaller or no associated MCR value. [0057] In implementations, transmission prioritization can be based on cast type. For instance, a transmit UE can transmit transport blocks on different carriers simultaneously which are carrying data of a different cast type, e.g., unicast, groupcast, and/or broadcast. According to implementations a UE can prioritize unicast traffic (e.g., PSSCH and/or PSCCH) over other cast type transmissions when the UE is under a power constraint. The UE, for example, first reduces transmission power of lower priority cast transmissions. ^[0058] In additional implementations a UE prioritizes PSSCH and/or PSCCH transmissions based on the corresponding destinations. The UE, for instance, first reduces the transmission power of sidelink transmissions which are dedicated to lower priority destinations. Further, a UE can perform power scaling when under a power constraint by considering a priority of a resource pool (e.g., a transmit pool) of a corresponding sidelink transmission on a carrier. A UE may also utilize a resource allocation mode for determining a priority of sidelink transmission. For instance, sidelink transmissions scheduled by gNB (e.g., mode1) can be prioritized over sidelink transmissions schedule by the UE, e.g., mode2 sidelink transmissions. Further, a UE may perform different registration area (RA) modes on different carriers. ^[0059] In implementations, a UE can calculate a transmission power for each sidelink carrier and/or cell for scenarios where the UE is configured with multiple sidelink carriers and/or cells. The UE, for example, adds up transmit powers (Tx power) for sidelink carriers and/or cells on which a sidelink transmission occurs in order to determine a total UE transmit power. If a total UE transmit power exceeds a maximum permitted UE transmit power, the UE can perform power scaling (e.g., power reduction) according to prioritization rules, e.g., the UE reduces transmission power for one or more sidelink transmissions. In at least one example a UE first reduces a transmission power of a sidelink transmission with a lowest priority. For scenarios where there are multiple sidelink transmissions with equal priority, UE implementation may specify how to perform transmit power reduction, e.g., in which order to perform the power reduction for sidelink transmissions of equivalent priority. [0060] According to one or more implementations, a maximum allowed transmit power is configured for a sidelink carrier and/or cell. For instance, utilizing a carrier-specific maximum allowed transmission power can accommodate factors like CBR (e.g., congestion level) of a sidelink carrier and/or cell. Further, different sidelink carriers may have a different coverage (e.g., based on a carrier frequency and/or serve traffic of different QoS requirements), which may result in configuration of a carrier-specific maximum transmit power. [0061] In scenarios where a network configures a maximum (e.g., allowed) transmit power for a sidelink carrier and/or cell, a UE may ensure that a transmit power for a sidelink transmission doesn’t exceed the maximum transmit power of the corresponding sidelink carrier and/or cell. For instance, in scenarios where a computed transmit power for a sidelink transmission on a sidelink carrier and/or cell exceeds a maximum allowed transmit power, a UE can scale down (e.g., reduce) a transmit power for the sidelink transmission such that it is equal to or smaller than the maximum allowed transmit power. [0062] In implementations, a minimum transmission power is configured (e.g., defined) for a sidelink transmission. A UE, for instance, is not to perform a sidelink transmission with less than the configured minimum transmission power for the sidelink transmission. A minimum transmit power associated with a sidelink transmission, for example, can ensure that a QoS requirement is met for the sidelink transmission. The minimum transmission power, for instance, is related to a priority and/or PC5 quality indicator (PQI) of the data of the sidelink transmission, e.g., a transmission with highest priority data multiplexed in a PSSCH transmission. In at least one implementation a UE determines a minimum transmission power of a sidelink transmission based on a configuration that specifies minimum transmission power. [0063] In implementations a network specifies transmission priority for different sidelink transmissions. For instance, a network configures for each transmission priority (e.g., priority of a PSSCH transmission as indicated in the corresponding SCI or logical channel priority) an associated minimum transmission power. Further, a network may also configure a minimum sidelink transmission power for a PSFCH transmission. ^[0064] According to one or more implementations a minimum transmission power for a PSFCH transmission may be based on a priority of data for which a hybrid automatic repeat request (HARQ) acknowledgement (ACK) and/or negative acknowledgement (NACK) is transmitted. Further, a minimum transmission power of a PSSCH transmission may also be based on whether control signaling (e.g., a MAC CE) is included in a transport block, e.g., a CSI MAC CE and/or IUC-related MAC CE. PSSCH transmissions including control signaling (e.g., a MAC CE) may have a higher minimum transmission power compared to a PSSCH transmission without control signaling. [0065] In implementations a UE skips a sidelink transmission for scenarios where an estimated transmission power for the sidelink transmission is less than the corresponding minimum transmission power. For example, in scenarios where UE is under a transmission power constraint and is to scale down (e.g., reduce) a transmission power of a sidelink transmission, it may occur that the resulting estimated transmission power after power scaling is less than a minimum transmission power. In such scenarios the UE may not perform the sidelink transmission and may skip the transmission and postpone the sidelink transmission to a subsequent transmission opportunity. Further, a UE may notify a network when it skips a sidelink transmission due to the lack of available transmission power, e.g., when an estimated sidelink transmission power is less than the associated minimum transmission power for a sidelink transmission. According to implementations, control signaling is introduced which indicates the skipping of a sidelink transmission due to insufficient available transmission power. This control signaling may be in one or more examples transmitted on a physical uplink control channel (PUCCH) and/or is multiplexed with other uplink control information (UCI). [0066] In other implementations a UE reduces the transmission power of a sidelink transmission up to a configured minimum transmission power for the sidelink transmission for cases that the UE is under a power constraint (e.g., is power limited) and further reduces the transmission power of the next higher priority sidelink transmission if the total transmission power after power scaling is still exceeding the maximum total allowed transmission power. According to this specific implementation a UE may not reduce the transmit power of a sidelink transmission below the minimum transmission power for the sidelink transmission or even to zero (e.g., skipping the sidelink transmission) but only up to the configured minimum transmission power. The UE, for instance, scales the transmit power of a first sidelink transmission to the configured minimum transmission power for the sidelink transmission before a transmit power of a second sidelink transmission of a higher priority than the first sidelink transmission is reduced. [0067] In at least some implementations a UE may signal an ACK on PUCCH in response to skipping a sidelink transmission due to the lack of transmission power on sidelink resources scheduled by gNB, e.g., according to mode1. Further, a UE may signal a NACK on PUCCH resources for scenarios where a scheduled sidelink transmission was not performed due to the power limitation to request sidelink resources for a retransmission of the skipped sidelink transmission. For instance, a UE triggers re-selection of sidelink resources for scenarios where a sidelink transmission is not performed due to the lack of transmit power, e.g., where available transmit power is less than the associated minimum transmit power for a particular sidelink transmission. For instance, a trigger is implemented for sidelink resource selection and/or reselection for scenarios where sidelink resources are selected autonomously by the transmit UE, e.g., mode2 resource allocation mode. ^[0068] Implementations also enable path loss reference to be considered for sidelink transmissions. For instance, one path loss reference can be configured for each sidelink carrier and/or cell when a UE is operating in CA mode, e.g., sidelink CA. Each sidelink carrier, for example, has an associated path loss reference which is used for the power control mechanism, e.g., for use in estimating the sidelink transmission power for a sidelink transmission, e.g., PSSCH, PSCCH, PSFCH, etc. Further, a path loss reference can be configured for a group of sidelink carriers and/or cells. In such scenarios there can be one common path loss reference for a group of sidelink carriers and/or cells. [0069] For unicast transmissions, the PSSCH power control can be configured to use the downlink path loss (PLDL) (e.g., between a gNB and transmit UE) only, a sidelink path loss (PLSL) (e.g., between a transmit UE and a receive UE) only, or both downlink path loss PLDL and sidelink path loss PL_SL. For instance, when a UE is configured with sidelink CA (e.g., with multiple sidelink carriers), the UE may not have a corresponding Uu carrier for each sidelink carrier which could be used as a path loss reference, e.g., PLDL. Therefore, and according to at least one implementation, the UE can use only a sidelink path loss PL_SL for scenarios where the UE is configured with sidelink CA. [0070] Implementations may also utilize PHR to provide power headroom information for UEs. For instance, utilizing PHR, a transmit UE can provide sidelink power headroom information to a gNB such as when the UE is configured with mode1 resource allocation mode. Power headroom information, for example, includes reference timing information which indicates for which sidelink resources sidelink power headroom was calculated. In some scenarios, such as for NR Uu, PHR is computed for a PUSCH transmission which includes the PHR MAC CE for PHR. For sidelink PHR, however, since a sidelink PHR may be computed for a different interface according to allocated sidelink resources (e.g., PC5 interface), a gNB may not be aware of, when receiving a sidelink PHR on the Uu interface, for which of the sidelink resource allocations the sidelink PHR was computed. Accordingly, implementations provide a sidelink PHR which includes information indicating for which sidelink transmission (e.g., sidelink grant) a PHR was computed. [0071] For instance, for scenarios where a UE is configured with sidelink CA, it is beneficial to provide sidelink PHR to a gNB scheduler, such as to avoid power limitations in the UE based on scheduled sidelink resources. Furthermore, since a sidelink transmission power (e.g., for PSSCH) may be determined based on a PLDL and/or PLSL, and a gNB may not be aware of the PLSL between a transmit UE and a receiver UE, the transmit UE can provide PHR-related information to the gNB. In implementations, a transmit UE reports PL_SL information to a gNB, e.g., sidelink path loss between the transmit UE and a receiver UE. Further, PLSL information can be reported per destination source pair. [0072] According to implementations, triggers for sidelink PHR and/or path loss information reporting are disclosed. For instance, for scenarios where a PL_DL and/or PL_SL change more than a threshold (e.g., a configured threshold such as specified in decibels (dB)), a UE can trigger the transmission of a sidelink PHR and/or path loss information to a gNB. If the transmission power for a sidelink transmission is calculated based on both PL_DL and PLSL, a UE can provide fresh power headroom information and/or path loss information to a gNB. In at least one example the path loss information includes PLSL between a transmit UE and a receiver UE and/or PLDL information. In implementations, sidelink PHR is conveyed in a MAC CE. Further, a transmit UE can transmit a sidelink PHR to a gNB based on predefined trigger conditions. In at least one example a UE triggers the transmission of a buffer status report (BSR) scheduling request (SR) in scenarios where a sidelink PHR is triggered and a UE has no available PUSCH resources for the transmission of the sidelink PHR MAC CE. At least one SR configuration, for example, is associated with the sidelink PHR MAC CE. [0073] FIG.2 illustrates an example of a block diagram 200 of a device 202 that supports power control for sidelink transmission in accordance with aspects of the present disclosure. The device 202 may be an example of a UE 104 as described herein. The device 202 may support wireless communication and/or network signaling with one or more base stations 102, other UEs 104, network entities and devices, or any combination thereof. The device 202 may include components for bi-directional communications including components for transmitting and receiving communications, such as a communications manager 204, a processor 206, a memory 208, a receiver 210, a transmitter 212, and an I/O controller 214. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses). [0074] The communications manager 204, the receiver 210, the transmitter 212, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. For example, the communications manager 204, the receiver 210, the transmitter 212, or various combinations or components thereof may support a method for performing one or more of the functions described herein. [0075] In some implementations, the communications manager 204, the receiver 210, the transmitter 212, or various combinations or components thereof may be implemented in hardware (e.g., in communications management circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure. In some implementations, the processor 206 and the memory 208 coupled with the processor 206 may be configured to perform one or more of the functions described herein (e.g., by executing, by the processor 206, instructions stored in the memory 208). [0076] Additionally or alternatively, in some implementations, the communications manager 204, the receiver 210, the transmitter 212, or various combinations or components thereof may be implemented in code (e.g., as communications management software or firmware) executed by the processor 206. If implemented in code executed by the processor 206, the functions of the communications manager 204, the receiver 210, the transmitter 212, or various combinations or components thereof may be performed by a general-purpose processor, a DSP, a central processing unit (CPU), an ASIC, an FPGA, or any combination of these or other programmable logic devices (e.g., configured as or otherwise supporting a means for performing the functions described in the present disclosure). [0077] In some implementations, the communications manager 204 may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the receiver 210, the transmitter 212, or both. For example, the communications manager 204 may receive information from the receiver 210, send information to the transmitter 212, or be integrated in combination with the receiver 210, the transmitter 212, or both to receive information, transmit information, or perform various other operations as described herein. Although the communications manager 204 is illustrated as a separate component, in some implementations, one or more functions described with reference to the communications manager 204 may be supported by or performed by the processor 206, the memory 208, or any combination thereof. For example, the memory 208 may store code, which may include instructions executable by the processor 206 to cause the device 202 to perform various aspects of the present disclosure as described herein, or the processor 206 and the memory 208 may be otherwise configured to perform or support such operations. [0078] For example, the communications manager 204 may support wireless communication and/or network signaling at a device (e.g., the device 202, a UE) in accordance with examples as disclosed herein. The communications manager 204 and/or other device components may be configured as or otherwise support an apparatus, such as a UE, including a transceiver; a processor coupled to the transceiver, the processor and the transceiver configured to cause the apparatus to: determine that a total transmit power for a set of sidelink transmissions on a group of sidelink carriers exceeds a maximum transmit power of the UE; order sidelink transmissions of the set of sidelink transmissions into a priority order based at least in part on at least one criteria; and adjust a transmit power of at least a first sidelink transmission of the set of sidelink transmissions based on the priority order such that a total transmit power for the set of sidelink transmissions is equal to or smaller than the maximum transmit power. [0079] Additionally, the apparatus (e.g., a UE) includes any one or combination of: where the apparatus groups the sidelink transmissions of the set of sidelink transmissions into sidelink channel groups, and where to order the sidelink transmissions includes to order the sidelink channel groups based at least in part on the at least one criteria; where a first group of the sidelink channel groups includes at least one PSFCH; where the first group of the sidelink channel groups including the at least one PSFCH has a highest transmission priority of the group of sidelink channels; where a first group of the sidelink channel groups includes at least one PSCCH; where a first group of the sidelink channel group includes at least one PSSCH. ^[0080] Additionally, the apparatus (e.g., a UE) includes any one or combination of: where to adjust the transmit power of the at least first sidelink transmission, the apparatus causes the UE to first adjust the transmit power of at least one PSSCH that does not include a sidelink MAC CE; where a first group of the sidelink channel group includes at least one PSSCH that includes sidelink control information; where the sidelink control information is signaled within a MAC CE; where to adjust the transmit power of the at least first sidelink transmission of the set of sidelink transmissions, the apparatus scales the transmit power of the at least first sidelink transmission to zero before a transmit power of a second sidelink transmission of a higher priority than the first sidelink transmission is reduced; the apparatus scales the transmit power of the at least first sidelink transmission to a minimum transmit power for the at least firm sidelink transmission before a transmit power of a second sidelink transmission of a higher priority than the first sidelink transmission is reduced; where: to order the sidelink transmissions, the apparatus prioritizes a second sidelink transmission over the at least first sidelink transmission based at least in part on the second sidelink transmission having a higher priority than the at least first sidelink transmission; and to adjust the transmit power of the at least first sidelink transmission, the apparatus reduces the transmit power of the at least first sidelink transmission based at least in part on the at least first sidelink transmission having a lower priority than the second sidelink transmission. [0081] Additionally, the apparatus (e.g., a UE) includes any one or combination of: where the total transmit power for the set of sidelink transmissions on the group of sidelink carriers includes a sum of individual sidelink transmissions of the set of sidelink transmissions; where the apparatus compares the adjusted transmit power of the at least first sidelink transmission to a predefined power threshold; where the apparatus does not perform the at least first sidelink transmission when the adjusted transmit power of the at least first sidelink transmission is below the predefined power threshold; where when the UE does not perform the at least first sidelink transmission, the apparatus transmits, to a network device, an indication that the at least first sidelink transmission was not performed based at least in part on the adjusted transmit power of the at least first sidelink transmission being below the predefined power threshold; where when the UE does not perform the at least first sidelink transmission, the apparatus triggers a reselection of at least one sidelink resource for the at least first sidelink transmission by the UE; where the at least one criteria includes a prioritization of transmissions by the UE, and where the prioritization includes, from highest priority and descending in priority: PSFCH transmission, PSCCH transmission with SCI, PSSCH transmission with sidelink MAC CE transmission, and PSCCH transmissions without MAC CE. [0082] Additionally, the apparatus (e.g., a UE) includes any one or combination of: where the at least one criteria includes a MCR, a second sidelink transmission of the set of sidelink transmissions includes an MCR value, and where to order sidelink transmissions, the apparatus prioritizes the second sidelink transmission over the at least first sidelink transmission based at least in part on the at least first sidelink transmission having a lower MCR value than the second sidelink transmission, or the at least first sidelink transmission having no MCR value; where the at least one criteria includes transmission cast type, a second sidelink transmission of the set of sidelink transmissions includes a unicast transmission, and where to order sidelink transmissions, the apparatus prioritizes the second sidelink transmission over the at least first sidelink transmission based at least in part on the at least first sidelink transmission having a cast type other than unicast; where the at least one criteria includes transmission destination priority, and where to order sidelink transmissions, the apparatus prioritizes a second sidelink transmission over the at least first sidelink transmission based at least in part on the second sidelink transmission having a higher priority transmission destination than the at least first sidelink transmission. ^[0083] Additionally, the apparatus (e.g., a UE) includes any one or combination of: where the at least one criteria includes transmission resource pool priority, and where to order sidelink transmissions, the apparatus prioritizes a second sidelink transmission over the at least first sidelink transmission based at least in part on the second sidelink transmission being performed in a higher priority transmission resource pool than the at least first sidelink transmission; where the at least one criteria includes a transmission resource allocation mode, and where to order sidelink transmissions, the apparatus prioritizes a second sidelink transmission over the at least first sidelink transmission based at least in part on the second sidelink transmission including a network allocated sidelink transmission and the at least first sidelink transmission including a UE allocated sidelink transmission; where the at least first sidelink transmission is associated with a sidelink carrier of the group of sidelink carriers, the sidelink carrier is associated with a maximum carrier transmit power, and where to adjust the transmit power of the at least first sidelink transmission, the apparatus reduces the transmit power of the at least first sidelink transmission until the transmit power of the at least first sidelink transmission is equal to or lesser than the maximum carrier transmit power. [0084] The communications manager 204 and/or other device components may be configured as or otherwise support a means for wireless communication and/or network signaling at a UE, including determining that a total transmit power for a set of sidelink transmissions on a group of sidelink carriers exceeds a maximum transmit power of a UE; ordering sidelink transmissions of the set of sidelink transmissions into a priority order based at least in part on at least one criteria; and adjusting a transmit power of at least a first sidelink transmission of the set of sidelink transmissions based on the priority order such that a total transmit power for the set of sidelink transmissions is equal to or smaller than the maximum transmit power. [0085] Additionally, wireless communication and/or network signaling at the UE includes any one or combination of: grouping the sidelink transmissions of the set of sidelink transmissions into sidelink channel groups, and where ordering the sidelink transmissions includes ordering the sidelink channel groups based at least in part on the at least one criteria; where a first group of the sidelink channel groups includes at least one PSFCH; where the first group of the sidelink channel groups including the at least one PSFCH has a highest transmission priority of the group of sidelink channels; where a first group of the sidelink channel groups includes at least one PSCCH; where a first group of the sidelink channel group includes at least one PSSCH; where adjusting the transmit power of the at least first sidelink transmission includes first adjusting the transmit power of at least one PSSCH that does not include a sidelink MAC CE; where a first group of the sidelink channel group includes at least one PSSCH that includes sidelink control information; where the sidelink control information is signaled within a MAC CE. ^[0086] Additionally, wireless communication and/or network signaling at the UE includes any one or combination of: where adjusting the transmit power of the at least first sidelink transmission of the set of sidelink transmissions includes scaling the transmit power of the at least first sidelink transmission to zero before a transmit power of a second sidelink transmission of a higher priority than the first sidelink transmission is reduced; where adjusting the transmit power of the at least first sidelink transmission of the set of sidelink transmissions includes scaling the transmit power of the at least first sidelink transmission to a minimum transmit power for the at least first sidelink transmission before a transmit power of a second sidelink transmission of a higher priority than the first sidelink transmission is reduced; where: ordering the sidelink transmissions includes prioritizing a second sidelink transmission over the at least first sidelink transmission based at least in part on the second sidelink transmission having a higher priority than the at least first sidelink transmission; and adjusting the transmit power of the at least first sidelink transmission includes reducing the transmit power of the at least first sidelink transmission based at least in part on the at least first sidelink transmission having a lower priority than the second sidelink transmission; where the total transmit power for the set of sidelink transmissions on the group of sidelink carriers includes a sum of individual sidelink transmissions of the set of sidelink transmissions; further including comparing the adjusted transmit power of the at least first sidelink transmission to a predefined power threshold; further including not performing the at least first sidelink transmission when the adjusted transmit power of the at least first sidelink transmission is below the predefined power threshold. ^[0087] Additionally, wireless communication and/or network signaling at the UE includes any one or combination of: where when the at least first sidelink transmission is not performed, the method further includes transmitting, to a network device, an indication that the at least first sidelink transmission was not performed based at least in part on the adjusted transmit power of the at least first sidelink transmission being below the predefined power threshold; where when the at least first sidelink transmission is not performed, the UE triggers a reselection of at least one sidelink resource for the at least first sidelink transmission by the UE; where the at least one criteria includes a prioritization of transmissions by the UE, and where the prioritization includes, from highest priority and descending in priority: PSFCH transmission, PSCCH transmission with SCI, PSSCH transmission with sidelink MAC CE transmission, and PSCCH transmissions without MAC CE; where the at least one criteria includes a MCR, a second sidelink transmission of the set of sidelink transmissions includes an MCR value, and where ordering sidelink transmissions includes prioritizing the second sidelink transmission over the at least first sidelink transmission based at least in part on the at least first sidelink transmission having a lower MCR value than the second sidelink transmission, or the at least first sidelink transmission having no MCR value. [0088] Additionally, wireless communication and/or network signaling at the UE includes any one or combination of: where the at least one criteria includes transmission cast type, a second sidelink transmission of the set of sidelink transmissions includes a unicast transmission, and where ordering sidelink transmissions includes prioritizing the second sidelink transmission over the at least first sidelink transmission based at least in part on the at least first sidelink transmission having a cast type other than unicast; where the at least one criteria includes transmission destination priority, and where ordering sidelink transmissions includes prioritizing a second sidelink transmission over the at least first sidelink transmission based at least in part on the second sidelink transmission having a higher priority transmission destination than the at least first sidelink transmission; where the at least one criteria includes transmission resource pool priority, and where ordering sidelink transmissions includes prioritizing a second sidelink transmission over the at least first sidelink transmission based at least in part on the second sidelink transmission being performed in a higher priority transmission resource pool than the at least first sidelink transmission. [0089] Additionally, wireless communication and/or network signaling at the UE includes any one or combination of: where the at least one criteria includes a transmission resource allocation mode, and where ordering sidelink transmissions includes prioritizing a second sidelink transmission over the at least first sidelink transmission based at least in part on the second sidelink transmission including a network allocated sidelink transmission and the at least first sidelink transmission including a UE allocated sidelink transmission; where the at least first sidelink transmission is associated with a sidelink carrier of the group of sidelink carriers, the sidelink carrier is associated with a maximum carrier transmit power, and where adjusting the transmit power of the at least first sidelink transmission includes reducing the transmit power of the at least first sidelink transmission until the transmit power of the at least first sidelink transmission is equal to or lesser than the maximum carrier transmit power. ^[0090] The communications manager 204 and/or other device components may be configured as or otherwise support an apparatus, such as a UE, including a transceiver; a processor coupled to the transceiver, the processor and the transceiver configured to cause the apparatus to: configure a path loss reference for at least one sidelink carrier of a set of sidelink carriers for CA by the UE; determine, based at least in part on the path loss reference, a transmit power for transmission over the at least one sidelink carrier of the set of sidelink carriers; and transmit over the at least one sidelink carrier using the determined transmit power. [0091] Additionally, the apparatus (e.g., a UE) includes any one or combination of: where each sidelink carrier includes a respective path loss reference, and where the path loss reference for the at least one sidelink carrier is configured individually for the at least one sidelink carrier; where the path loss reference is configured as a common path loss reference for the set of sidelink carriers as a group; where the path loss reference includes a downlink path loss reference; where the path loss reference includes a sidelink path loss reference; where the path loss reference is based on both a downlink path loss reference and a sidelink path loss reference; [0092] The communications manager 204 and/or other device components may be configured as or otherwise support a means for wireless communication and/or network signaling at a UE, including configuring a path loss reference for at least one sidelink carrier of a set of sidelink carriers for CA by a UE; determining, based at least in part on the path loss reference, a transmit power for transmission over the at least one sidelink carrier of the set of sidelink carriers; and transmitting over the at least one sidelink carrier using the determined transmit power. [0093] Additionally, wireless communication and/or network signaling at the UE includes any one or combination of: where each sidelink carrier includes a respective path loss reference, and where the path loss reference for the at least one sidelink carrier is configured individually for the at least one sidelink carrier; where the path loss reference is configured as a common path loss reference for the set of sidelink carriers as a group; where the path loss reference includes a downlink path loss reference; where the path loss reference includes a sidelink path loss reference; where the path loss reference is based on both a downlink path loss reference and a sidelink path loss reference. [0094] The communications manager 204 and/or other device components may be configured as or otherwise support an apparatus, such as a UE, including a transceiver; a processor coupled to the transceiver, the processor and the transceiver configured to cause the apparatus to: generate a power indication identifying a sidelink power headroom of the UE; transmit, to a network device, the power indication; and receive, from the network device, a sidelink resource allocation for sidelink transmission by the UE. ^[0095] Additionally, the apparatus (e.g., a UE) includes any one or combination of: where the power indication includes reference timing information that identifies sidelink resources used to calculate the sidelink power headroom; where the power indication includes sidelink path loss information for sidelink path loss between the UE and a receiving UE; where the apparatus generates the power indication based at least in part on CA operation of the UE; where the apparatus generates the power indication based at least in part on a sidelink power reporting trigger; where the sidelink power reporting trigger includes an indication of at least one of that a sidelink path loss changes more than a threshold, or that a downlink path loss changes more than a threshold; where the apparatus transmits the power indication to the network device via a MAC CE. [0096] The communications manager 204 and/or other device components may be configured as or otherwise support a means for wireless communication and/or network signaling at a UE, including generating a power indication identifying a sidelink power headroom of a UE; transmitting, to a network device, the power indication; and receiving, from the network device, a sidelink resource allocation for sidelink transmission by the UE. [0097] Additionally, wireless communication and/or network signaling at the UE includes any one or combination of: where the power indication includes reference timing information that identifies sidelink resources used to calculate the sidelink power headroom; where the power indication includes sidelink path loss information for sidelink path loss between the UE and a receiving UE; further including generating the power indication based at least in part on CA operation of the UE; further including generating the power indication based at least in part on a sidelink power reporting trigger; where the sidelink power reporting trigger includes an indication of at least one of that a sidelink path loss changes more than a threshold, or that a downlink path loss changes more than a threshold; further including transmitting the power indication to the network device via a MAC CE. ^[0098] The processor 206 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some implementations, the processor 206 may be configured to operate a memory array using a memory controller. In some other implementations, a memory controller may be integrated into the processor 206. The processor 206 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 208) to cause the device 202 to perform various functions of the present disclosure. [0099] The memory 208 may include random access memory (RAM) and read-only memory (ROM). The memory 208 may store computer-readable, computer-executable code including instructions that, when executed by the processor 206 cause the device 202 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some implementations, the code may not be directly executable by the processor 206 but may cause a computer (e.g., when compiled and executed) to perform functions described herein. In some implementations, the memory 208 may include, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices. ^[0100] The I/O controller 214 may manage input and output signals for the device 202. The I/O controller 214 may also manage peripherals not integrated into the device 202. In some implementations, the I/O controller 214 may represent a physical connection or port to an external peripheral. In some implementations, the I/O controller 214 may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In some implementations, the I/O controller 214 may be implemented as part of a processor, such as the processor 206. In some implementations, a user may interact with the device 202 via the I/O controller 214 or via hardware components controlled by the I/O controller 214. [0101] In some implementations, the device 202 may include a single antenna 216. However, in some other implementations, the device 202 may have more than one antenna 216, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The receiver 210 and the transmitter 212 may communicate bi-directionally, via the one or more antennas 216, wired, or wireless links as described herein. For example, the receiver 210 and the transmitter 212 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver may also include a modem to modulate the packets, to provide the modulated packets to one or more antennas 216 for transmission, and to demodulate packets received from the one or more antennas 216. [0102] FIG.3 illustrates an example of a block diagram 300 of a device 302 that supports power control for sidelink transmission in accordance with aspects of the present disclosure. The device 302 may be an example of a base station 102, such as a gNB as described herein. The device 302 may support wireless communication and/or network signaling with one or more base stations 102, other UEs 104, core network devices and functions (e.g., core network 106), or any combination thereof. The device 302 may include components for bi-directional communications including components for transmitting and receiving communications, such as a communications manager 304, a processor 306, a memory 308, a receiver 310, a transmitter 312, and an I/O controller 314. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses). [0103] The communications manager 304, the receiver 310, the transmitter 312, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. For example, the communications manager 304, the receiver 310, the transmitter 312, or various combinations or components thereof may support a method for performing one or more of the functions described herein. [0104] In some implementations, the communications manager 304, the receiver 310, the transmitter 312, or various combinations or components thereof may be implemented in hardware (e.g., in communications management circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure. In some implementations, the processor 306 and the memory 308 coupled with the processor 306 may be configured to perform one or more of the functions described herein (e.g., by executing, by the processor 306, instructions stored in the memory 308). [0105] Additionally or alternatively, in some implementations, the communications manager 304, the receiver 310, the transmitter 312, or various combinations or components thereof may be implemented in code (e.g., as communications management software or firmware) executed by the processor 306. If implemented in code executed by the processor 306, the functions of the communications manager 304, the receiver 310, the transmitter 312, or various combinations or components thereof may be performed by a general-purpose processor, a DSP, a central processing unit (CPU), an ASIC, an FPGA, or any combination of these or other programmable logic devices (e.g., configured as or otherwise supporting a means for performing the functions described in the present disclosure). ^[0106] In some implementations, the communications manager 304 may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the receiver 310, the transmitter 312, or both. For example, the communications manager 304 may receive information from the receiver 310, send information to the transmitter 312, or be integrated in combination with the receiver 310, the transmitter 312, or both to receive information, transmit information, or perform various other operations as described herein. Although the communications manager 304 is illustrated as a separate component, in some implementations, one or more functions described with reference to the communications manager 304 may be supported by or performed by the processor 306, the memory 308, or any combination thereof. For example, the memory 308 may store code, which may include instructions executable by the processor 306 to cause the device 302 to perform various aspects of the present disclosure as described herein, or the processor 306 and the memory 308 may be otherwise configured to perform or support such operations. [0107] For example, the communications manager 304 may support wireless communication and/or network signaling at a device (e.g., the device 302, such as a base station) in accordance with examples as disclosed herein. ^[0108] The communications manager 304 and/or other device components may be configured as or otherwise support an apparatus, such as a base station and/or other network device, including a transceiver; a processor coupled to the transceiver, the processor and the transceiver configured to cause the apparatus to: generate a criteria indication indicating at least one criteria for ordering sidelink transmission by a UE; and transmit the criteria indication to the UE. [0109] Additionally, the apparatus (e.g., a base station) includes any one or combination of: where the criteria indication identifies transmission priorities for different types of sidelink transmissions; where the at least one criteria includes a prioritization of transmissions by the UE, and where the prioritization includes, from highest priority and descending in priority: PSFCH transmission, PSCCH transmission with SCI, PSCCH transmission with sidelink MAC CE transmission, and PSCCH transmissions with priority indicators; where the at least one criteria includes an indication that a first sidelink transmission with a higher MCR value is to be prioritized over a second sidelink transmission with a lower MCR value or no MCR value; where the at least one criteria includes one or more of: a transmission prioritization indication based on cast type; a transmission prioritization indication based on transmission destination priority; a transmission prioritization indication based on transmission resource pool priority; or a transmission prioritization indication based on transmission resource allocation mode; where the apparatus receives, from the UE, an indication that a sidelink transmission was not performed based at least in part on an adjusted transmit power of the sidelink transmission being below a predefined power threshold; generates, based at least in part on the indication that the sidelink transmission was not performed, a resource indication including sidelink resources reselected for the UE; and transmits, to the UE, the resource indication. [0110] The communications manager 304 and/or other device components may be configured as or otherwise support a means for wireless communication and/or network signaling at a base station and/or other network device, including generating a criteria indication indicating at least one criteria for ordering sidelink transmission by a UE; and transmitting the criteria indication to the UE. ^[0111] Additionally, wireless communication at the base station and/or other network device includes any one or combination of: where the criteria indication identifies transmission priorities for different types of sidelink transmissions; where the at least one criteria includes a prioritization of transmissions by the UE, and where the prioritization includes, from highest priority and descending in priority: PSFCH transmission, PSCCH transmission with SCI, PSCCH transmission with sidelink MAC CE transmission, and PSCCH transmissions with priority indicators; where the at least one criteria includes an indication that a first sidelink transmission with a higher MCR value is to be prioritized over a second sidelink transmission with a lower MCR value or no MCR value; where the at least one criteria includes one or more of: a transmission prioritization indication based on cast type; a transmission prioritization indication based on transmission destination priority; a transmission prioritization indication based on transmission resource pool priority; or a transmission prioritization indication based on transmission resource allocation mode; further including: receiving, from the UE, an indication that a sidelink transmission was not performed based at least in part on an adjusted transmit power of the sidelink transmission being below a predefined power threshold; generating, based at least in part on the indication that the sidelink transmission was not performed, a resource indication including sidelink resources reselected for the UE; and transmitting, to the UE, the resource indication. [0112] The communications manager 304 and/or other device components may be configured as or otherwise support an apparatus, such as a base station and/or other network device, including a transceiver; a processor coupled to the transceiver, the processor and the transceiver configured to cause the apparatus to: receive, from a UE, a power indication indicating a sidelink power headroom of the UE; generate, based at least in part on the power indication, a sidelink resource allocation for the UE; and transmit the sidelink resource allocation to the UE. [0113] Additionally, the apparatus (e.g., a base station) includes any one or combination of: where the power indication includes reference timing information that identifies sidelink resources used to calculate the sidelink power headroom; where the power indication includes sidelink path loss information for sidelink path loss between the UE and a different UE; where the power indication is received via a MAC CE. ^[0114] The communications manager 304 and/or other device components may be configured as or otherwise support a means for wireless communication and/or network signaling at a base station and/or other network device, including receiving, from a UE, a power indication indicating a sidelink power headroom of the UE; generating, based at least in part on the power indication, a sidelink resource allocation for the UE; and transmitting the sidelink resource allocation to the UE. [0115] Additionally, wireless communication at the base station and/or other network device includes any one or combination of: where the power indication includes reference timing information that identifies sidelink resources used to calculate the sidelink power headroom; where the power indication includes sidelink path loss information for sidelink path loss between the UE and a different UE; where the power indication is received via a MAC CE. ^[0116] The processor 306 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some implementations, the processor 306 may be configured to operate a memory array using a memory controller. In some other implementations, a memory controller may be integrated into the processor 306. The processor 306 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 308) to cause the device 302 to perform various functions of the present disclosure. [0117] The memory 308 may include random access memory (RAM) and read-only memory (ROM). The memory 308 may store computer-readable, computer-executable code including instructions that, when executed by the processor 306 cause the device 302 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some implementations, the code may not be directly executable by the processor 306 but may cause a computer (e.g., when compiled and executed) to perform functions described herein. In some implementations, the memory 308 may include, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices. [0118] The I/O controller 314 may manage input and output signals for the device 302. The I/O controller 314 may also manage peripherals not integrated into the device 302. In some implementations, the I/O controller 314 may represent a physical connection or port to an external peripheral. In some implementations, the I/O controller 314 may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In some implementations, the I/O controller 314 may be implemented as part of a processor, such as the processor 306. In some implementations, a user may interact with the device 302 via the I/O controller 314 or via hardware components controlled by the I/O controller 314. [0119] In some implementations, the device 302 may include a single antenna 316. However, in some other implementations, the device 302 may have more than one antenna 316, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The receiver 310 and the transmitter 312 may communicate bi-directionally, via the one or more antennas 316, wired, or wireless links as described herein. For example, the receiver 310 and the transmitter 312 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver may also include a modem to modulate the packets, to provide the modulated packets to one or more antennas 316 for transmission, and to demodulate packets received from the one or more antennas 316. [0120] FIG. 4 illustrates a flowchart of a method 400 that supports power control for sidelink transmission in accordance with aspects of the present disclosure. The operations of the method 400 may be implemented and performed by a device or its components, such as a UE 104 as described with reference to FIGs.1 and 2. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware. [0121] At 402, the method may include determining that a total transmit power for a set of sidelink transmissions on a group of sidelink carriers exceeds a maximum transmit power of the UE. The operations of 402 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 402 may be performed by a device as described with reference to FIG.1. ^[0122] At 404, the method may include ordering sidelink transmissions of the set of sidelink transmissions into a priority order based at least in part on at least one criteria. The operations of 404 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 404 may be performed by a device as described with reference to FIG.1. [0123] At 406, the method may include adjusting a transmit power of at least a first sidelink transmission of the set of sidelink transmissions based on the priority order such that a total transmit power for the set of sidelink transmissions is equal to or smaller than the maximum transmit power. The operations of 406 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 406 may be performed by a device as described with reference to FIG.1. [0124] FIG. 5 illustrates a flowchart of a method 500 that supports power control for sidelink transmission in accordance with aspects of the present disclosure. The operations of the method 500 may be implemented and performed by a device or its components, such as a UE 104 as described with reference to FIGs.1 and 2. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware. [0125] At 502, the method may include comparing an adjusted transmit power of a first sidelink transmission to a predefined power threshold. The operations of 502 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 502 may be performed by a device as described with reference to FIG. 1. ^[0126] At 504, the method may include determining whether the adjusted transmit power is below predefined threshold. The operations of 504 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 504 may be performed by a device as described with reference to FIG.1. [0127] At 506, the method may include, if the adjusted transmit power is not below predefined threshold (“No”), performing the first sidelink transmission. The operations of 506 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 506 may be performed by a device as described with reference to FIG.1. [0128] At 508, the method may include if the adjusted transmit power is below predefined threshold (“Yes”), not performing the first sidelink transmission The operations of 508 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 508 may be performed by a device as described with reference to FIG.1. [0129] At 510, the method may include transmitting, to a network device, an indication that the first sidelink transmission was not performed based at least in part on the adjusted transmit power of the first sidelink transmission being below the predefined power threshold. The operations of 510 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 510 may be performed by a device as described with reference to FIG.1. [0130] At 512, the method may include receiving, from the network device, a sidelink resource allocation for retransmission of the first sidelink transmission. The operations of 512 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 512 may be performed by a device as described with reference to FIG.1. ^[0131] FIG. 6 illustrates a flowchart of a method 600 that supports power control for sidelink transmission in accordance with aspects of the present disclosure. The operations of the method 600 may be implemented and performed by a device or its components, such as a UE 104 as described with reference to FIGs.1 and 2. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware. ^[0132] At 602, the method may include configuring a path loss reference for at least one sidelink carrier of a set of sidelink carriers for CA by a UE. The operations of 602 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 602 may be performed by a device as described with reference to FIG. 1. [0133] At 604, the method may include determining, based at least in part on the path loss reference, a transmit power for transmission over the at least one sidelink carrier of the set of sidelink carriers. The operations of 604 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 604 may be performed by a device as described with reference to FIG.1. [0134] At 606, the method may include transmitting over the at least one sidelink carrier using the determined transmit power. The operations of 606 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 606 may be performed by a device as described with reference to FIG.1. [0135] FIG. 7 illustrates a flowchart of a method 700 that supports power control for sidelink transmission in accordance with aspects of the present disclosure. The operations of the method 700 may be implemented and performed by a device or its components, such as a UE 104 as described with reference to FIGs.1 and 2. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware. ^[0136] At 702, the method may include generating a power indication identifying a sidelink power headroom of a UE. The operations of 702 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 702 may be performed by a device as described with reference to FIG.1. ^[0137] At 704, the method may include transmitting, to a network device, the power indication. The operations of 704 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 704 may be performed by a device as described with reference to FIG.1. [0138] At 706, the method may include receiving, from the network device, a sidelink resource allocation for sidelink transmission by the UE. The operations of 706 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 706 may be performed by a device as described with reference to FIG. 1. [0139] FIG. 8 illustrates a flowchart of a method 800 that supports power control for sidelink transmission in accordance with aspects of the present disclosure. The operations of the method 800 may be implemented and performed by a device or its components, such as a base station 102, e.g., gNB, as described with reference to FIGs. 1 through 3. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware. [0140] At 802, the method may include generating a criteria indication indicating at least one criteria for ordering sidelink transmission by a UE. The operations of 802 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 802 may be performed by a device as described with reference to FIG. 1. [0141] At 804, the method may include transmitting the criteria indication to the UE. The operations of 804 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 804 may be performed by a device as described with reference to FIG.1. ^[0142] FIG. 9 illustrates a flowchart of a method 900 that supports power control for sidelink transmission in accordance with aspects of the present disclosure. The operations of the method 900 may be implemented and performed by a device or its components, such as a base station 102, e.g., gNB, as described with reference to FIGs. 1 through 3. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware. ^[0143] At 902, the method may include receiving, from a UE, an indication that a sidelink transmission was not performed based at least in part on an adjusted transmit power of the sidelink transmission being below a predefined power threshold. The operations of 902 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 902 may be performed by a device as described with reference to FIG. 1. [0144] At 904, the method may include generating, based at least in part on the indication that the sidelink transmission was not performed, a resource indication including sidelink resources reselected for the UE. The operations of 904 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 904 may be performed by a device as described with reference to FIG.1. [0145] At 906, the method may include transmitting, to the UE, the resource indication. The operations of 906 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 906 may be performed by a device as described with reference to FIG.1. [0146] FIG. 10 illustrates a flowchart of a method 1000 that supports power control for sidelink transmission in accordance with aspects of the present disclosure. The operations of the method 1000 may be implemented and performed by a device or its components, such as a base station 102, e.g., gNB, as described with reference to FIGs. 1 through 3. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware. ^[0147] At 1002, the method may include receiving, from a UE, a power indication indicating a sidelink power headroom of the UE. The operations of 1002 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1002 may be performed by a device as described with reference to FIG.1. ^[0148] At 1004, the method may include generating, based at least in part on the power indication, a sidelink resource allocation for the UE. The operations of 1004 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1004 may be performed by a device as described with reference to FIG. 1. [0149] At 1006, the method may include transmitting the sidelink resource allocation to the UE. The operations of 1006 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1006 may be performed by a device as described with reference to FIG.1. [0150] It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined. The order in which the methods are described is not intended to be construed as a limitation, and any number or combination of the described method operations may be performed in any order to perform a method, or an alternate method. ^[0151] The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A 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. ^[0152] 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 computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a 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. [0153] Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory 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, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory 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. ^[0154] Any connection may be 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 computer-readable medium. Disk and disc, as used herein, include 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. ^[0155] As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of”) indicates an inclusive 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). Similarly, a list of one or more 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). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. Further, as used herein, including in the claims, a “set” may include one or more elements. [0156] The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described example. ^[0157] The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

CLAIMS What is claimed is: 1. A user equipment (UE) comprising: a transceiver; and a processor coupled to the transceiver, the processor and the transceiver configured to cause the UE to: determine that a total transmit power for a set of sidelink transmissions on a group of sidelink carriers exceeds a maximum transmit power of the UE; order sidelink transmissions of the set of sidelink transmissions into a priority order based at least in part on at least one criteria; and adjust a transmit power of at least a first sidelink transmission of the set of sidelink transmissions based on the priority order such that a total transmit power for the set of sidelink transmissions is equal to or smaller than the maximum transmit power.

2. The UE of claim 1, wherein the processor and the transceiver are configured to cause the UE to group the sidelink transmissions of the set of sidelink transmissions into sidelink channel groups, and wherein to order the sidelink transmissions comprises to order the sidelink channel groups based at least in part on the at least one criteria.

3. The UE of claim 2, wherein a first group of the sidelink channel groups comprises at least one physical sidelink feedback channel (PSFCH).

4. The UE of claim 3, wherein the first group of the sidelink channel groups comprising the at least one PSFCH has a highest transmission priority of the group of sidelink channels.

5. The UE of claim 2, wherein a first group of the sidelink channel groups comprises at least one physical sidelink control channel (PSCCH).

6. The UE of claim 2, wherein a first group of the sidelink channel group comprises at least one physical sidelink shared channel (PSSCH).

7. The UE of claim 6, wherein to adjust the transmit power of the at least first sidelink transmission, the processor and the transceiver are configured to cause the UE to first adjust the transmit power of at least one PSSCH that does not include a sidelink media access control (MAC) control element (CE).

8. The UE of claim 2, wherein a first group of the sidelink channel group comprises at least one physical sidelink shared channel (PSSCH) that comprises sidelink control information.

9. The UE of claim 8, wherein the sidelink control information is signaled within a media access control (MAC) control element (CE).

10. The UE of claim 1, wherein to adjust the transmit power of the at least first sidelink transmission of the set of sidelink transmissions, the processor and the transceiver are configured to cause the UE to scale the transmit power of the at least first sidelink transmission to zero before a transmit power of a second sidelink transmission of a higher priority than the first sidelink transmission is reduced.

11. The UE of claim 1, wherein the total transmit power for the set of sidelink transmissions on the group of sidelink carriers comprises a sum of individual sidelink transmissions of the set of sidelink transmissions.

12. The UE of claim 1, wherein the processor and the transceiver are configured to cause the UE to compare the adjusted transmit power of the at least first sidelink transmission to a predefined power threshold.

13. The UE of claim 12, wherein the processor and the transceiver are configured to cause the UE to not perform the at least first sidelink transmission when the adjusted transmit power of the at least first sidelink transmission is below the predefined power threshold.

14. A user equipment (UE) comprising: a transceiver; and a processor coupled to the transceiver, the processor and the transceiver configured to cause the UE to: configure a path loss reference for at least one sidelink carrier of a set of sidelink carriers for CA by the UE; determine, based at least in part on the path loss reference, a transmit power for transmission over the at least one sidelink carrier of the set of sidelink carriers; and transmit over the at least one sidelink carrier using the determined transmit power.

15. The UE of claim 14, wherein each sidelink carrier comprises a respective path loss reference, and wherein the path loss reference for the at least one sidelink carrier is configured individually for the at least one sidelink carrier.

16. The UE of claim 14, wherein the path loss reference is configured as a common path loss reference for the set of sidelink carriers as a group.

17. The UE of claim 14, wherein the path loss reference comprises a downlink path loss reference.

18. The UE of claim 14, wherein the path loss reference comprises a sidelink path loss reference.

19. The UE of claim 14, wherein the path loss reference is based on both a downlink path loss reference and a sidelink path loss reference.

20. A user equipment (UE) comprising: a transceiver; and a processor coupled to the transceiver, the processor and the transceiver configured to cause the UE to: generate a power indication identifying a sidelink power headroom of the UE; transmit, to a network device, the power indication; and receive, from the network device, a sidelink resource allocation for sidelink transmission by the UE.