BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

[0001] Aspects of the disclosure relate generally to wireless communications.

2. Description of the Related Art

[0002] Wireless communication systems have developed through various generations, including a first-generation analog wireless phone service (1G), a second-generation (2G) digital wireless phone service (including interim 2.5G and 2.75G networks), a third-generation (3G) high speed data, Internet-capable wireless service and a fourth-generation (4G) service (e.g., Long Term Evolution (LTE) or WiMax). There are presently many different types of wireless communication systems in use, including cellular and personal communications service (PCS) systems. Examples of known cellular systems include the cellular analog advanced mobile phone system (AMPS), and digital cellular systems based on code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), the Global System for Mobile communications (GSM), etc.

[0003] A fifth generation (5G) wireless standard, referred to as New Radio (NR), enables higher data transfer speeds, greater numbers of connections, and better coverage, among other improvements. The 5G standard, according to the Next Generation Mobile Networks Alliance, is designed to provide higher data rates as compared to previous standards, more accurate positioning (e.g., based on reference signals for positioning (RS-P), such as downlink, uplink, or sidelink positioning reference signals (PRS)) and other technical enhancements.

[0004] Leveraging the increased data rates and decreased latency of 5G, among other things, vehicle-to-everything (V2X) communication technologies are being implemented to support autonomous driving applications, such as wireless communications between vehicles, between vehicles and the roadside infrastructure, between vehicles and pedestrians, etc. SUMMARY

[0005] The following presents a simplified summary relating to one or more aspects disclosed herein. Thus, the following summary should not be considered an extensive overview relating to all contemplated aspects, nor should the following summary be considered to identify key or critical elements relating to all contemplated aspects or to delineate the scope associated with any particular aspect. Accordingly, the following summary has the sole purpose to present certain concepts relating to one or more aspects relating to the mechanisms disclosed herein in a simplified form to precede the detailed description presented below.

[0006] In an aspect, a method of wireless communication performed by a user equipment (UE) includes detecting a conflict between a first sidelink reference signal transmission from a first reference signal sidelink UE and a second sidelink reference signal transmission from a second sidelink UE, wherein the first sidelink reference signal transmission at least partially overlaps with the second sidelink reference signal transmission in at least one time resource, at least one frequency resource, or both; and transmitting a collision report to a third sidelink UE, the collision report including at least a collision type indicator indicating whether the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier.

[0007] In an aspect, a method of wireless communication performed by a user equipment (UE) includes transmitting a reservation request to reserve a plurality of transmission occasions on a sidelink channel for transmission of a plurality of repetitions of a sidelink positioning reference signal (SL-PRS) resource; transmitting, to at least one recipient UE, a first repetition of the plurality of repetitions of the SL-PRS resource during a first transmission occasion of the plurality of transmission occasions; and transmitting or refraining from transmitting at least a second repetition of the plurality of repetitions of the SL-PRS resource during at least a second transmission occasion of the plurality of transmission occasions based on feedback or lack of feedback from the at least one recipient UE.

[0008] In an aspect, a user equipment (UE) includes a memory; at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: detect a conflict between a first sidelink reference signal transmission from a first sidelink UE and a second sidelink reference signal transmission from a second sidelink UE, wherein the first sidelink reference signal transmission at least partially overlaps with the second sidelink reference signal transmission in at least one time resource, at least one frequency resource, or both; and transmit, via the at least one transceiver, a collision report to a third sidelink UE, the collision report including at least a collision type indicator indicating whether the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier.

[0009] In an aspect, a user equipment (UE) includes a memory; at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: transmit, via the at least one transceiver, a reservation request to reserve a plurality of transmission occasions on a sidelink channel for transmission of a plurality of repetitions of a sidelink positioning reference signal (SL-PRS) resource; transmit, via the at least one transceiver, to at least one recipient UE, a first repetition of the plurality of repetitions of the SL-PRS resource during a first transmission occasion of the plurality of transmission occasions; and transmit, via the at least one transceiver, or refrain from transmitting at least a second repetition of the plurality of repetitions of the SL-PRS resource during at least a second transmission occasion of the plurality of transmission occasions based on feedback or lack of feedback from the at least one recipient UE.

[0010] In an aspect, a user equipment (UE) includes means for detecting a conflict between a first sidelink reference signal transmission from a first sidelink UE and a second sidelink reference signal transmission from a second sidelink UE, wherein the first sidelink reference signal transmission at least partially overlaps with the second sidelink reference signal transmission in at least one time resource, at least one frequency resource, or both; and means for transmitting a collision report to a third sidelink UE, the collision report including at least a collision type indicator indicating whether the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier.

[0011] In an aspect, a user equipment (UE) includes means for transmitting a reservation request to reserve a plurality of transmission occasions on a sidelink channel for transmission of a plurality of repetitions of a sidelink positioning reference signal (SL-PRS) resource; means for transmitting, to at least one recipient UE, a first repetition of the plurality of repetitions of the SL-PRS resource during a first transmission occasion of the plurality of transmission occasions; and means for transmitting or refraining from transmitting at least a second repetition of the plurality of repetitions of the SL-PRS resource during at least a second transmission occasion of the plurality of transmission occasions based on feedback or lack of feedback from the at least one recipient UE.

[0012] In an aspect, a non-transitory computer-readable medium stores computer-executable instructions that, when executed by a user equipment (UE), cause the UE to: detect a conflict between a first sidelink reference signal transmission from a first sidelink UE and a second sidelink reference signal transmission from a second sidelink UE, wherein the first sidelink reference signal transmission at least partially overlaps with the second sidelink reference signal transmission in at least one time resource, at least one frequency resource, or both; and transmit a collision report to a third sidelink UE, the collision report including at least a collision type indicator indicating whether the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier.

[0013] In an aspect, a non-transitory computer-readable medium stores computer-executable instructions that, when executed by an UE, cause the UE to: transmit a reservation request to reserve a plurality of transmission occasions on a sidelink channel for transmission of a plurality of repetitions of a sidelink positioning reference signal (SL-PRS) resource; transmit, to at least one recipient UE, a first repetition of the plurality of repetitions of the SL-PRS resource during a first transmission occasion of the plurality of transmission occasions; and transmit or refrain from transmitting at least a second repetition of the plurality of repetitions of the SL-PRS resource during at least a second transmission occasion of the plurality of transmission occasions based on feedback or lack of feedback from the at least one recipient UE.

[0014] Other objects and advantages associated with the aspects disclosed herein will be apparent to those skilled in the art based on the accompanying drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are presented to aid in the description of various aspects of the disclosure and are provided solely for illustration of the aspects and not limitation thereof.

[0016] FIG. 1 illustrates an example wireless communications system, according to aspects of the disclosure.

[0017] FIGS. 2A and 2B illustrate example wireless network structures, according to aspects of the disclosure. [0018] FIGS. 3A, 3B, and 3C are simplified block diagrams of several sample aspects of components that may be employed in a user equipment (UE), a base station, and a network entity, respectively, and configured to support communications as taught herein.

[0019] FIGS. 4A and 4B illustrate various scenarios of interest for sidelink-only or joint Uu and sidelink positioning, according to aspects of the disclosure.

[0020] FIGS. 5 A and 5B are diagrams of example sidelink slot structures with and without feedback resources, according to aspects of the disclosure.

[0021] FIG. 6 is a diagram illustrating an example resource pool for positioning within a sidelink resource pool, according to aspects of the disclosure.

[0022] FIG. 7 is a diagram illustrating additional aspects of sidelink resource pools and resource pools for positioning, according to aspects of the disclosure.

[0023] FIG. 8 is a diagram illustrating how a UE can determine a future conflict among scheduled sidelink transmission resources, according to aspects of the disclosure.

[0024] FIG. 9 is a diagram illustrating a past conflict among sidelink transmission resources, according to aspects of the disclosure.

[0025] FIG. 10 is a diagram illustrating an example scenario in which a UE has reserved three opportunities for the transmission of a specific sidelink positioning reference signal (SL- PRS) resource, according to aspects of the disclosure.

[0026] FIGS. 11 and 12 illustrate example methods of wireless communication, according to aspects of the disclosure.

DETAILED DESCRIPTION

[0027] Aspects of the disclosure are provided in the following description and related drawings directed to various examples provided for illustration purposes. Alternate aspects may be devised without departing from the scope of the disclosure. Additionally, well-known elements of the disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of the disclosure.

[0028] The words “exemplary” and/or “example” are used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” and/or “example” is not necessarily to be construed as preferred or advantageous over other aspects. Likewise, the term “aspects of the disclosure” does not require that all aspects of the disclosure include the discussed feature, advantage or mode of operation. [0029] Those of skill in the art will appreciate that the information and signals described below 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 below may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof, depending in part on the particular application, in part on the desired design, in part on the corresponding technology, etc.

[0030] Further, many aspects are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be recognized that various actions described herein can be performed by specific circuits (e.g., application specific integrated circuits (ASICs)), by program instructions being executed by one or more processors, or by a combination of both. Additionally, the sequence(s) of actions described herein can be considered to be embodied entirely within any form of non- transitory computer-readable storage medium having stored therein a corresponding set of computer instructions that, upon execution, would cause or instruct an associated processor of a device to perform the functionality described herein. Thus, the various aspects of the disclosure may be embodied in a number of different forms, all of which have been contemplated to be within the scope of the claimed subject matter. In addition, for each of the aspects described herein, the corresponding form of any such aspects may be described herein as, for example, “logic configured to” perform the described action.

[0031] As used herein, the terms “user equipment” (UE), “vehicle UE” (V-UE), “pedestrian UE” (P-UE), and “base station” are not intended to be specific or otherwise limited to any particular radio access technology (RAT), unless otherwise noted. In general, a UE may be any wireless communication device (e.g., vehicle on-board computer, vehicle navigation device, mobile phone, router, tablet computer, laptop computer, asset locating device, wearable (e.g., smartwatch, glasses, augmented reality (AR) / virtual reality (VR) headset, etc.), vehicle (e.g., automobile, motorcycle, bicycle, etc.), Internet of Things (loT) device, etc.) used by a user to communicate over a wireless communications network. A UE may be mobile or may (e.g., at certain times) be stationary, and may communicate with a radio access network (RAN). As used herein, the term “UE” may be referred to interchangeably as a “mobile device,” an “access terminal” or “AT,” a “client device,” a “wireless device,” a “subscriber device,” a “subscriber terminal,” a “subscriber station,” a “user terminal” or UT, a “mobile terminal,” a “mobile station,” or variations thereof.

[0032] A V-UE is a type of UE and may be any in-vehicle wireless communication device, such as a navigation system, a warning system, a heads-up display (HUD), an on-board computer, an in-vehicle infotainment system, an automated driving system (ADS), an advanced driver assistance system (ADAS), etc. Alternatively, a V-UE may be a portable wireless communication device (e.g., a cell phone, tablet computer, etc.) that is carried by the driver of the vehicle or a passenger in the vehicle. The term “V-UE” may refer to the in-vehicle wireless communication device or the vehicle itself, depending on the context. A P-UE is a type of UE and may be a portable wireless communication device that is carried by a pedestrian (i.e., a user that is not driving or riding in a vehicle). Generally, UEs can communicate with a core network via a RAN, and through the core network the UEs can be connected with external networks such as the Internet and with other UEs. Of course, other mechanisms of connecting to the core network and/or the Internet are also possible for the UEs, such as over wired access networks, wireless local area network (WLAN) networks (e.g., based on Institute of Electrical and Electronics Engineers (IEEE) 802.11, etc.) and so on.

[0033] A base station may operate according to one of several RATs in communication with UEs depending on the network in which it is deployed, and may be alternatively referred to as an access point (AP), a network node, a NodeB, an evolved NodeB (eNB), a next generation eNB (ng-eNB), a New Radio (NR) Node B (also referred to as a gNB or gNodeB), etc. A base station may be used primarily to support wireless access by UEs including supporting data, voice and/or signaling connections for the supported UEs. In some systems a base station may provide purely edge node signaling functions while in other systems it may provide additional control and/or network management functions. A communication link through which UEs can send signals to a base station is called an uplink (UL) channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). A communication link through which the base station can send signals to UEs is called a downlink (DL) or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). As used herein the term traffic channel (TCH) can refer to either an UL / reverse or DL / forward traffic channel.

[0034] The term “base station” may refer to a single physical transmission-reception point (TRP) or to multiple physical TRPs that may or may not be co-located. For example, where the term “base station” refers to a single physical TRP, the physical TRP may be an antenna of the base station corresponding to a cell (or several cell sectors) of the base station. Where the term “base station” refers to multiple co-located physical TRPs, the physical TRPs may be an array of antennas (e.g., as in a multiple-input multiple-output (MIMO) system or where the base station employs beamforming) of the base station. Where the term “base station” refers to multiple non-co-located physical TRPs, the physical TRPs may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transport medium) or a remote radio head (RRH) (a remote base station connected to a serving base station). Alternatively, the non-co-located physical TRPs may be the serving base station receiving the measurement report from the UE and a neighbor base station whose reference radio frequency (RF) signals the UE is measuring. Because a TRP is the point from which a base station transmits and receives wireless signals, as used herein, references to transmission from or reception at a base station are to be understood as referring to a particular TRP of the base station.

[0035] In some implementations that support positioning of UEs, a base station may not support wireless access by UEs (e.g., may not support data, voice, and/or signaling connections for UEs), but may instead transmit reference RF signals to UEs to be measured by the UEs and/or may receive and measure signals transmitted by the UEs. Such base stations may be referred to as positioning beacons (e.g., when transmitting RF signals to UEs) and/or as location measurement units (e.g., when receiving and measuring RF signals from UEs).

[0036] An “RF signal” comprises an electromagnetic wave of a given frequency that transports information through the space between a transmitter and a receiver. As used herein, a transmitter may transmit a single “RF signal” or multiple “RF signals” to a receiver. However, the receiver may receive multiple “RF signals” corresponding to each transmitted RF signal due to the propagation characteristics of RF signals through multipath channels. The same transmitted RF signal on different paths between the transmitter and receiver may be referred to as a “multipath” RF signal. As used herein, an RF signal may also be referred to as a “wireless signal” or simply a “signal” where it is clear from the context that the term “signal” refers to a wireless signal or an RF signal. [0037] FIG. 1 illustrates an example wireless communications system 100, according to aspects of the disclosure. The wireless communications system 100 (which may also be referred to as a wireless wide area network (WWAN)) may include various base stations 102 (labelled “BS”) and various UEs 104. The base stations 102 may include macro cell base stations (high power cellular base stations) and/or small cell base stations (low power cellular base stations). In an aspect, the macro cell base stations 102 may include eNBs and/or ng-eNBs where the wireless communications system 100 corresponds to an LTE network, or gNBs where the wireless communications system 100 corresponds to a NR network, or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, etc.

[0038] The base stations 102 may collectively form a RAN and interface with a core network 170 (e.g., an evolved packet core (EPC) or 5G core (5GC)) through backhaul links 122, and through the core network 170 to one or more location servers 172 (e.g., a location management function (LMF) or a secure user plane location (SUPL) location platform (SLP)). The location server(s) 172 may be part of core network 170 or may be external to core network 170. A location server 172 may be integrated with a base station 102. A UE 104 may communicate with a location server 172 directly or indirectly. For example, a UE 104 may communicate with a location server 172 via the base station 102 that is currently serving that UE 104. A UE 104 may also communicate with a location server 172 through another path, such as via an application server (not shown), via another network, such as via a wireless local area network (WLAN) access point (AP) (e.g., AP 150 described below), and so on. For signaling purposes, communication between a UE 104 and a location server 172 may be represented as an indirect connection (e.g., through the core network 170, etc.) or a direct connection (e.g., as shown via direct connection 128), with the intervening nodes (if any) omitted from a signaling diagram for clarity.

[0039] In addition to other functions, the base stations 102 may perform functions that relate to one or more of transferring user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (e.g., through the EPC / 5GC) over backhaul links 134, which may be wired or wireless. [0040] The base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. In an aspect, one or more cells may be supported by a base station 102 in each geographic coverage area 110. A “cell” is a logical communication entity used for communication with a base station (e.g., over some frequency resource, referred to as a carrier frequency, component carrier, carrier, band, or the like), and may be associated with an identifier (e.g., a physical cell identifier (PCI), an enhanced cell identifier (ECI), a virtual cell identifier (VCI), a cell global identifier (CGI), etc.) for distinguishing cells operating via the same or a different carrier frequency. In some cases, different cells may be configured according to different protocol types (e.g., machine-type communication (MTC), narrowband loT (NB-IoT), enhanced mobile broadband (eMBB), or others) that may provide access for different types of UEs. Because a cell is supported by a specific base station, the term “cell” may refer to either or both the logical communication entity and the base station that supports it, depending on the context. In some cases, the term “cell” may also refer to a geographic coverage area of abase station (e.g., a sector), insofar as a carrier frequency can be detected and used for communication within some portion of geographic coverage areas 110.

[0041] While neighboring macro cell base station 102 geographic coverage areas 110 may partially overlap (e.g., in a handover region), some of the geographic coverage areas 110 may be substantially overlapped by a larger geographic coverage area 110. For example, a small cell base station 102' (labelled “SC” for “small cell”) may have a geographic coverage area 110' that substantially overlaps with the geographic coverage area 110 of one or more macro cell base stations 102. A network that includes both small cell and macro cell base stations may be known as a heterogeneous network. A heterogeneous network may also include home eNBs (HeNBs), which may provide service to a restricted group known as a closed subscriber group (CSG).

[0042] The communication links 120 between the base stations 102 and the UEs 104 may include uplink (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use MIMO antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links 120 may be through one or more carrier frequencies. Allocation of carriers may be asymmetric with respect to downlink and uplink (e.g., more or less carriers may be allocated for downlink than for uplink).

[0043] The wireless communications system 100 may further include a wireless local area network (WLAN) access point (AP) 150 in communication with WLAN stations (STAs) 152 via communication links 154 in an unlicensed frequency spectrum (e.g., 5 GHz). When communicating in an unlicensed frequency spectrum, the WLAN STAs 152 and/or the WLAN AP 150 may perform a clear channel assessment (CCA) or listen before talk (LBT) procedure prior to communicating in order to determine whether the channel is available.

[0044] The small cell base station 102' may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell base station 102' may employ LTE or NR technology and use the same 5 GHz unlicensed frequency spectrum as used by the WLAN AP 150. The small cell base station 102', employing LTE / 5G in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network. NR in unlicensed spectrum may be referred to as NR-U. LTE in an unlicensed spectrum may be referred to as LTE-U, licensed assisted access (LAA), or MulteFire.

[0045] The wireless communications system 100 may further include a mmW base station 180 that may operate in millimeter wave (mmW) frequencies and/or near mmW frequencies in communication with a UE 182. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in this band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW/near mmW radio frequency band have high path loss and a relatively short range. The mmW base station 180 and the UE 182 may utilize beamforming (transmit and/or receive) over a mmW communication link 184 to compensate for the extremely high path loss and short range. Further, it will be appreciated that in alternative configurations, one or more base stations 102 may also transmit using mmW or near mmW and beamforming. Accordingly, it will be appreciated that the foregoing illustrations are merely examples and should not be construed to limit the various aspects disclosed herein. [0046] Transmit beamforming is a technique for focusing an RF signal in a specific direction. Traditionally, when a network node (e.g., a base station) broadcasts an RF signal, it broadcasts the signal in all directions (omni-directionally). With transmit beamforming, the network node determines where a given target device (e.g., a UE) is located (relative to the transmitting network node) and projects a stronger downlink RF signal in that specific direction, thereby providing a faster (in terms of data rate) and stronger RF signal for the receiving device(s). To change the directionality of the RF signal when transmitting, a network node can control the phase and relative amplitude of the RF signal at each of the one or more transmitters that are broadcasting the RF signal. For example, a network node may use an array of antennas (referred to as a “phased array” or an “antenna array”) that creates abeam of RF waves that can be “steered” to point in different directions, without actually moving the antennas. Specifically, the RF current from the transmitter is fed to the individual antennas with the correct phase relationship so that the radio waves from the separate antennas add together to increase the radiation in a desired direction, while cancelling to suppress radiation in undesired directions.

[0047] Transmit beams may be quasi-co-located, meaning that they appear to the receiver (e.g., a UE) as having the same parameters, regardless of whether or not the transmitting antennas of the network node themselves are physically co-located. In NR, there are four types of quasi-co-location (QCL) relations. Specifically, a QCL relation of a given type means that certain parameters about a second reference RF signal on a second beam can be derived from information about a source reference RF signal on a source beam. Thus, if the source reference RF signal is QCL Type A, the receiver can use the source reference RF signal to estimate the Doppler shift, Doppler spread, average delay, and delay spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type B, the receiver can use the source reference RF signal to estimate the Doppler shift and Doppler spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type C, the receiver can use the source reference RF signal to estimate the Doppler shift and average delay of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type D, the receiver can use the source reference RF signal to estimate the spatial receive parameter of a second reference RF signal transmitted on the same channel.

[0048] In receive beamforming, the receiver uses a receive beam to amplify RF signals detected on a given channel. For example, the receiver can increase the gain setting and/or adjust the phase setting of an array of antennas in a particular direction to amplify (e.g., to increase the gain level of) the RF signals received from that direction. Thus, when a receiver is said to beamform in a certain direction, it means the beam gain in that direction is high relative to the beam gain along other directions, or the beam gain in that direction is the highest compared to the beam gain in that direction of all other receive beams available to the receiver. This results in a stronger received signal strength (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to- interference-plus-noise ratio (SINR), etc.) of the RF signals received from that direction. [0049] Transmit and receive beams may be spatially related. A spatial relation means that parameters for a second beam (e.g., a transmit or receive beam) for a second reference signal can be derived from information about a first beam (e.g., a receive beam or a transmit beam) for a first reference signal. For example, a UE may use a particular receive beam to receive a reference downlink reference signal (e.g., synchronization signal block (SSB)) from a base station. The UE can then form a transmit beam for sending an uplink reference signal (e.g., sounding reference signal (SRS)) to that base station based on the parameters of the receive beam.

[0050] Note that a “downlink” beam may be either a transmit beam or a receive beam, depending on the entity forming it. For example, if a base station is forming the downlink beam to transmit a reference signal to a UE, the downlink beam is a transmit beam. If the UE is forming the downlink beam, however, it is a receive beam to receive the downlink reference signal. Similarly, an “uplink” beam may be either a transmit beam or a receive beam, depending on the entity forming it. For example, if a base station is forming the uplink beam, it is an uplink receive beam, and if a UE is forming the uplink beam, it is an uplink transmit beam.

[0051] The electromagnetic spectrum is often subdivided, based on frequency/wavelength, into various classes, bands, channels, etc. In 5G NR two initial operating bands have been identified as frequency range designations FR1 (410 MHz - 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). It should be understood that although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as a “Sub-6 GHz” band in various documents and articles. A similar nomenclature issue sometimes occurs with regard to FR2, which is often referred to (interchangeably) as a “millimeter wave” band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHz - 300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band.

[0052] The frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Recent 5G NR studies have identified an operating band for these mid-band frequencies as frequency range designation FR3 (7.125 GHz - 24.25 GHz). Frequency bands falling within FR3 may inherit FR1 characteristics and/or FR2 characteristics, and thus may effectively extend features of FR1 and/or FR2 into mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operation beyond 52.6 GHz. For example, three higher operating bands have been identified as frequency range designations FR4a or FR4-1 (52.6 GHz - 71 GHz), FR4 (52.6 GHz - 114.25 GHz), and FR5 (114.25 GHz - 300 GHz). Each of these higher frequency bands falls within the EHF band.

[0053] With the above aspects in mind, unless specifically stated otherwise, it should be understood that the term “sub-6 GHz” or the like if used herein may broadly represent frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. Further, unless specifically stated otherwise, it should be understood that the term “millimeter wave” or the like if used herein may broadly represent frequencies that may include mid-band frequencies, may be within FR2, FR4, FR4-a or FR4-1, and/or FR5, or may be within the EHF band.

[0054] In a multi-carrier system, such as 5G, one of the carrier frequencies is referred to as the “primary carrier” or “anchor carrier” or “primary serving cell” or “PCell,” and the remaining carrier frequencies are referred to as “secondary carriers” or “secondary serving cells” or “SCells.” In carrier aggregation, the anchor carrier is the carrier operating on the primary frequency (e.g., FR1) utilized by a UE 104/182 and the cell in which the UE 104/182 either performs the initial radio resource control (RRC) connection establishment procedure or initiates the RRC connection re-establishment procedure. The primary carrier carries all common and UE-specific control channels, and may be a carrier in a licensed frequency (however, this is not always the case). A secondary carrier is a carrier operating on a second frequency (e.g., FR2) that may be configured once the RRC connection is established between the UE 104 and the anchor carrier and that may be used to provide additional radio resources. In some cases, the secondary carrier may be a carrier in an unlicensed frequency. The secondary carrier may contain only necessary signaling information and signals, for example, those that are UE-specific may not be present in the secondary carrier, since both primary uplink and downlink carriers are typically UE-specific. This means that different UEs 104/182 in a cell may have different downlink primary carriers. The same is true for the uplink primary carriers. The network is able to change the primary carrier of any UE 104/182 at any time. This is done, for example, to balance the load on different carriers. Because a “serving cell” (whether a PCell or an SCell) corresponds to a carrier frequency / component carrier over which some base station is communicating, the term “cell,” “serving cell,” “component carrier,” “carrier frequency,” and the like can be used interchangeably.

[0055] For example, still referring to FIG. 1, one of the frequencies utilized by the macro cell base stations 102 may be an anchor carrier (or “PCell”) and other frequencies utilized by the macro cell base stations 102 and/or the mmW base station 180 may be secondary carriers (“SCells”). The simultaneous transmission and/or reception of multiple carriers enables the UE 104/182 to significantly increase its data transmission and/or reception rates. For example, two 20 MHz aggregated carriers in a multi-carrier system would theoretically lead to a two-fold increase in data rate (i.e., 40 MHz), compared to that attained by a single 20 MHz carrier.

[0056] In the example of FIG. 1, any of the illustrated UEs (shown in FIG. 1 as a single UE 104 for simplicity) may receive signals 124 from one or more Earth orbiting space vehicles (SVs) 112 (e.g., satellites). In an aspect, the SVs 112 may be part of a satellite positioning system that a UE 104 can use as an independent source of location information. A satellite positioning system typically includes a system of transmitters (e.g., SVs 112) positioned to enable receivers (e.g., UEs 104) to determine their location on or above the Earth based, at least in part, on positioning signals (e.g., signals 124) received from the transmitters. Such a transmitter typically transmits a signal marked with a repeating pseudo-random noise (PN) code of a set number of chips. While typically located in SVs 112, transmitters may sometimes be located on ground-based control stations, base stations 102, and/or other UEs 104. A UE 104 may include one or more dedicated receivers specifically designed to receive signals 124 for deriving geo location information from the SVs 112.

[0057] In a satellite positioning system, the use of signals 124 can be augmented by various satellite-based augmentation systems (SBAS) that may be associated with or otherwise enabled for use with one or more global and/or regional navigation satellite systems. For example an SBAS may include an augmentation system(s) that provides integrity information, differential corrections, etc., such as the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay Service (EGNOS), the Multifunctional Satellite Augmentation System (MSAS), the Global Positioning System (GPS) Aided Geo Augmented Navigation or GPS and Geo Augmented Navigation system (GAGAN), and/or the like. Thus, as used herein, a satellite positioning system may include any combination of one or more global and/or regional navigation satellites associated with such one or more satellite positioning systems.

[0058] In an aspect, SVs 112 may additionally or alternatively be part of one or more nonterrestrial networks (NTNs). In an NTN, an SV 112 is connected to an earth station (also referred to as a ground station, NTN gateway, or gateway), which in turn is connected to an element in a 5G network, such as a modified base station 102 (without a terrestrial antenna) or a network node in a 5GC. This element would in turn provide access to other elements in the 5G network and ultimately to entities external to the 5G network, such as Internet web servers and other user devices. In that way, a UE 104 may receive communication signals (e.g., signals 124) from an SV 112 instead of, or in addition to, communication signals from a terrestrial base station 102.

[0059] Leveraging the increased data rates and decreased latency of NR, among other things, vehicle-to-everything (V2X) communication technologies are being implemented to support intelligent transportation systems (ITS) applications, such as wireless communications between vehicles (vehicle-to-vehicle (V2V)), between vehicles and the roadside infrastructure (vehicle-to-infrastructure (V2I)), and between vehicles and pedestrians (vehicle-to-pedestrian (V2P)). The goal is for vehicles to be able to sense the environment around them and communicate that information to other vehicles, infrastructure, and personal mobile devices. Such vehicle communication will enable safety, mobility, and environmental advancements that current technologies are unable to provide. Once fully implemented, the technology is expected to reduce unimpaired vehicle crashes by 80%.

[0060] Still referring to FIG. 1, the wireless communications system 100 may include multiple V-UEs 160 that may communicate with base stations 102 over communication links 120 using the Uu interface (i.e., the air interface between a UE and a base station). V-UEs 160 may also communicate directly with each other over a wireless sidelink 162, with a roadside unit (RSU) 164 (a roadside access point) over a wireless sidelink 166, or with sidelink-capable UEs 104 over a wireless sidelink 168 using the PC5 interface (i.e., the air interface between sidelink-capable UEs). A wireless sidelink (or just “sidelink”) is an adaptation of the core cellular (e.g., LTE, NR) standard that allows direct communication between two or more UEs without the communication needing to go through a base station. Sidelink communication may be unicast or multicast, and may be used for device- to-device (D2D) media-sharing, V2V communication, V2X communication (e.g., cellular V2X (cV2X) communication, enhanced V2X (eV2X) communication, etc.), emergency rescue applications, etc. One or more of a group of V-UEs 160 utilizing sidelink communications may be within the geographic coverage area 110 of a base station 102. Other V-UEs 160 in such a group may be outside the geographic coverage area 110 of a base station 102 or be otherwise unable to receive transmissions from a base station 102. In some cases, groups of V-UEs 160 communicating via sidelink communications may utilize a one-to-many (1:M) system in which each V-UE 160 transmits to every other V- UE 160 in the group. In some cases, a base station 102 facilitates the scheduling of resources for sidelink communications. In other cases, sidelink communications are carried out between V-UEs 160 without the involvement of a base station 102.

[0061] In an aspect, the sidelinks 162, 166, 168 may operate over a wireless communication medium of interest, which may be shared with other wireless communications between other vehicles and/or infrastructure access points, as well as other RATs. A “medium” may be composed of one or more time, frequency, and/or space communication resources (e.g., encompassing one or more channels across one or more carriers) associated with wireless communication between one or more transmitter / receiver pairs.

[0062] In an aspect, the sidelinks 162, 166, 168 may be cV2X links. A first generation of cV2X has been standardized in LTE, and the next generation is expected to be defined in NR. cV2X is a cellular technology that also enables device-to-device communications. In the U.S. and Europe, cV2X is expected to operate in the licensed ITS band in sub-6GHz. Other bands may be allocated in other countries. Thus, as a particular example, the medium of interest utilized by sidelinks 162, 166, 168 may correspond to at least a portion of the licensed ITS frequency band of sub-6GHz. However, the present disclosure is not limited to this frequency band or cellular technology.

[0063] In an aspect, the sidelinks 162, 166, 168 may be dedicated short-range communications (DSRC) links. DSRC is a one-way or two-way short-range to medium-range wireless communication protocol that uses the wireless access for vehicular environments (WAVE) protocol, also known as IEEE 802. l ip, for V2V, V2I, and V2P communications. IEEE 802.1 Ip is an approved amendment to the IEEE 802.11 standard and operates in the licensed ITS band of 5.9 GHz (5.85-5.925 GHz) in the U.S. In Europe, IEEE 802.1 Ip operates in the ITS G5A band (5.875 - 5.905 MHz). Other bands may be allocated in other countries. The V2V communications briefly described above occur on the Safety Channel, which in the U.S. is typically a 10 MHz channel that is dedicated to the purpose of safety. The remainder of the DSRC band (the total bandwidth is 75 MHz) is intended for other services of interest to drivers, such as road rules, tolling, parking automation, etc. Thus, as a particular example, the mediums of interest utilized by sidelinks 162, 166, 168 may correspond to at least a portion of the licensed ITS frequency band of 5.9 GHz.

[0064] Alternatively, the medium of interest may correspond to at least a portion of an unlicensed frequency band shared among various RATs. Although different licensed frequency bands have been reserved for certain communication systems (e.g., by a government entity such as the Federal Communications Commission (FCC) in the United States), these systems, in particular those employing small cell access points, have recently extended operation into unlicensed frequency bands such as the Unlicensed National Information Infrastructure (U-NII) band used by wireless local area network (WLAN) technologies, most notably IEEE 802.1 lx WLAN technologies generally referred to as “Wi-Fi.” Example systems of this type include different variants of CDMA systems, TDMA systems, FDMA systems, orthogonal FDMA (OFDMA) systems, single-carrier FDMA (SC-FDMA) systems, and so on.

[0065] Communications between the V-UEs 160 are referred to as V2V communications, communications between the V-UEs 160 and the one or more RSUs 164 are referred to as V2I communications, and communications between the V-UEs 160 and one or more UEs 104 (where the UEs 104 are P-UEs) are referred to as V2P communications. The V2V communications between V-UEs 160 may include, for example, information about the position, speed, acceleration, heading, and other vehicle data of the V-UEs 160. The V2I information received at a V-UE 160 from the one or more RSUs 164 may include, for example, road rules, parking automation information, etc. The V2P communications between a V-UE 160 and a UE 104 may include information about, for example, the position, speed, acceleration, and heading of the V-UE 160 and the position, speed (e.g., where the UE 104 is carried by a user on a bicycle), and heading of the UE 104.

[0066] Note that although FIG. 1 only illustrates two of the UEs as V-UEs (V-UEs 160), any of the illustrated UEs (e.g., UEs 104, 152, 182, 190) may be V-UEs. In addition, while only the V-UEs 160 and a single UE 104 have been illustrated as being connected over a sidelink, any of the UEs illustrated in FIG. 1, whether V-UEs, P-UEs, etc., may be capable of sidelink communication. Further, although only UE 182 was described as being capable of beam forming, any of the illustrated UEs, including V-UEs 160, may be capable of beam forming. Where V-UEs 160 are capable of beam forming, they may beam form towards each other (i.e., towards other V-UEs 160), towards RSUs 164, towards other UEs (e.g., UEs 104, 152, 182, 190), etc. Thus, in some cases, V-UEs 160 may utilize beamforming over sidelinks 162, 166, and 168.

[0067] The wireless communications system 100 may further include one or more UEs, such as UE 190, that connects indirectly to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links. In the example of FIG. 1, UE 190 has a D2D P2P link 192 with one of the UEs 104 connected to one of the base stations 102 (e.g., through which UE 190 may indirectly obtain cellular connectivity) and a D2D P2P link 194 with WLAN STA 152 connected to the WLAN AP 150 (through which UE 190 may indirectly obtain WLAN-based Internet connectivity). In an example, the D2D P2P links 192 and 194 may be supported with any well-known D2D RAT, such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth®, and so on. As another example, the D2D P2P links 192 and 194 may be sidelinks, as described above with reference to sidelinks 162, 166, and 168.

[0068] FIG. 2A illustrates an example wireless network structure 200. For example, a 5GC 210 (also referred to as a Next Generation Core (NGC)) can be viewed functionally as control plane (C-plane) functions 214 (e.g., UE registration, authentication, network access, gateway selection, etc.) and user plane (U-plane) functions 212, (e.g., UE gateway function, access to data networks, IP routing, etc.) which operate cooperatively to form the core network. User plane interface (NG-U) 213 and control plane interface (NG-C) 215 connect the gNB 222 to the 5GC 210 and specifically to the user plane functions 212 and control plane functions 214, respectively. In an additional configuration, an ng-eNB 224 may also be connected to the 5GC 210 via NG-C 215 to the control plane functions 214 and NG-U 213 to user plane functions 212. Further, ng-eNB 224 may directly communicate with gNB 222 via a backhaul connection 223. In some configurations, a Next Generation RAN (NG-RAN) 220 may have one or more gNBs 222, while other configurations include one or more of both ng-eNBs 224 and gNBs 222. Either (or both) gNB 222 or ng-eNB 224 may communicate with one or more UEs 204 (e.g., any of the UEs described herein).

[0069] Another optional aspect may include a location server 230, which may be in communication with the 5GC 210 to provide location assistance for UE(s) 204. The location server 230 can be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternately may each correspond to a single server. The location server 230 can be configured to support one or more location services for UEs 204 that can connect to the location server 230 via the core network, 5GC 210, and/or via the Internet (not illustrated). Further, the location server 230 may be integrated into a component of the core network, or alternatively may be external to the core network (e.g., a third party server, such as an original equipment manufacturer (OEM) server or service server).

[0070] FIG. 2B illustrates another example wireless network structure 250. A 5GC 260 (which may correspond to 5GC 210 in FIG. 2A) can be viewed functionally as control plane functions, provided by an access and mobility management function (AMF) 264, and user plane functions, provided by a user plane function (UPF) 262, which operate cooperatively to form the core network (i.e., 5GC 260). The functions of the AMF 264 include registration management, connection management, reachability management, mobility management, lawful interception, transport for session management (SM) messages between one or more UEs 204 (e.g., any of the UEs described herein) and a session management function (SMF) 266, transparent proxy services for routing SM messages, access authentication and access authorization, transport for short message service (SMS) messages between the UE 204 and the short message service function (SMSF) (not shown), and security anchor functionality (SEAF). The AMF 264 also interacts with an authentication server function (AUSF) (not shown) and the UE 204, and receives the intermediate key that was established as a result of the UE 204 authentication process. In the case of authentication based on a UMTS (universal mobile telecommunications system) subscriber identity module (USIM), the AMF 264 retrieves the security material from the AUSF. The functions of the AMF 264 also include security context management (SCM). The SCM receives a key from the SEAF that it uses to derive access-network specific keys. The functionality of the AMF 264 also includes location services management for regulatory services, transport for location services messages between the UE 204 and a location management function (LMF) 270 (which acts as a location server 230), transport for location services messages between the NG-RAN 220 and the LMF 270, evolved packet system (EPS) bearer identifier allocation for interworking with the EPS, and UE 204 mobility event notification. In addition, the AMF 264 also supports functionalities for non-3GPP (Third Generation Partnership Project) access networks.

[0071] Functions of the UPF 262 include acting as an anchor point for intra-/inter-RAT mobility (when applicable), acting as an external protocol data unit (PDU) session point of interconnect to a data network (not shown), providing packet routing and forwarding, packet inspection, user plane policy rule enforcement (e.g., gating, redirection, traffic steering), lawful interception (user plane collection), traffic usage reporting, quality of service (QoS) handling for the user plane (e.g., uplink/ downlink rate enforcement, reflective QoS marking in the downlink), uplink traffic verification (service data flow (SDF) to QoS flow mapping), transport level packet marking in the uplink and downlink, downlink packet buffering and downlink data notification triggering, and sending and forwarding of one or more “end markers” to the source RAN node. The UPF 262 may also support transfer of location services messages over a user plane between the UE 204 and a location server, such as an SLP 272.

[0072] The functions of the SMF 266 include session management, UE Internet protocol (IP) address allocation and management, selection and control of user plane functions, configuration of traffic steering at the UPF 262 to route traffic to the proper destination, control of part of policy enforcement and QoS, and downlink data notification. The interface over which the SMF 266 communicates with the AMF 264 is referred to as the Nil interface.

[0073] Another optional aspect may include an LMF 270, which may be in communication with the 5GC 260 to provide location assistance for UEs 204. The LMF 270 can be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternately may each correspond to a single server. The LMF 270 can be configured to support one or more location services for UEs 204 that can connect to the LMF 270 via the core network, 5GC 260, and/or via the Internet (not illustrated). The SLP 272 may support similar functions to the LMF 270, but whereas the LMF 270 may communicate with the AMF 264, NG-RAN 220, and UEs 204 over a control plane (e.g., using interfaces and protocols intended to convey signaling messages and not voice or data), the SLP 272 may communicate with UEs 204 and external clients (e.g., third-party server 274) over a user plane (e.g., using protocols intended to carry voice and/or data like the transmission control protocol (TCP) and/or IP).

[0074] Yet another optional aspect may include a third-party server 274, which may be in communication with the LMF 270, the SLP 272, the 5GC 260 (e.g., via the AMF 264 and/or the UPF 262), the NG-RAN 220, and/or the UE 204 to obtain location information (e.g., a location estimate) for the UE 204. As such, in some cases, the third-party server 274 may be referred to as a location services (LCS) client or an external client. The third- party server 274 can be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternately may each correspond to a single server.

[0075] User plane interface 263 and control plane interface 265 connect the 5GC 260, and specifically the UPF 262 and AMF 264, respectively, to one or more gNBs 222 and/or ng-eNBs 224 in the NG-RAN 220. The interface between gNB(s) 222 and/or ng-eNB(s) 224 and the AMF 264 is referred to as the “N2” interface, and the interface between gNB(s) 222 and/or ng-eNB(s) 224 and the UPF 262 is referred to as the “N3” interface. The gNB(s) 222 and/or ng-eNB(s) 224 of the NG-RAN 220 may communicate directly with each other via backhaul connections 223, referred to as the “Xn-C” interface. One or more of gNBs 222 and/or ng-eNBs 224 may communicate with one or more UEs 204 over a wireless interface, referred to as the “Uu” interface.

[0076] The functionality of a gNB 222 may be divided between a gNB central unit (gNB-CU) 226, one or more gNB distributed units (gNB-DUs) 228, and one or more gNB radio units (gNB-RUs) 229. A gNB-CU 226 is a logical node that includes the base station functions of transferring user data, mobility control, radio access network sharing, positioning, session management, and the like, except for those functions allocated exclusively to the gNB-DU(s) 228. More specifically, the gNB-CU 226 generally host the radio resource control (RRC), service data adaptation protocol (SDAP), and packet data convergence protocol (PDCP) protocols of the gNB 222. A gNB-DU 228 is a logical node that generally hosts the radio link control (RLC) and medium access control (MAC) layer of the gNB 222. Its operation is controlled by the gNB-CU 226. One gNB-DU 228 can support one or more cells, and one cell is supported by only one gNB-DU 228. The interface 232 between the gNB-CU 226 and the one or more gNB-DUs 228 is referred to as the “Fl” interface. The physical (PHY) layer functionality of a gNB 222 is generally hosted by one or more standalone gNB-RUs 229 that perform functions such as power amplification and signal transmission/reception. The interface between a gNB-DU 228 and a gNB-RU 229 is referred to as the “Fx” interface. Thus, a UE 204 communicates with the gNB-CU 226 via the RRC, SDAP, and PDCP layers, with a gNB-DU 228 via the RLC and MAC layers, and with a gNB-RU 229 via the PHY layer.

[0077] FIGS. 3A, 3B, and 3C illustrate several example components (represented by corresponding blocks) that may be incorporated into a UE 302 (which may correspond to any of the UEs described herein), a base station 304 (which may correspond to any of the base stations described herein), and a network entity 306 (which may correspond to or embody any of the network functions described herein, including the location server 230 and the LMF 270, or alternatively may be independent from the NG-RAN 220 and/or 5GC 210/260 infrastructure depicted in FIGS. 2A and 2B, such as a private network) to support the operations described herein. It will be appreciated that these components may be implemented in different types of apparatuses in different implementations (e.g., in an ASIC, in a system-on-chip (SoC), etc.). The illustrated components may also be incorporated into other apparatuses in a communication system. For example, other apparatuses in a system may include components similar to those described to provide similar functionality. Also, a given apparatus may contain one or more of the components. For example, an apparatus may include multiple transceiver components that enable the apparatus to operate on multiple carriers and/or communicate via different technologies.

[0078] The UE 302 and the base station 304 each include one or more wireless wide area network (WWAN) transceivers 310 and 350, respectively, providing means for communicating (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for refraining from transmitting, etc.) via one or more wireless communication networks (not shown), such as an NR network, an LTE network, a GSM network, and/or the like. The WWAN transceivers 310 and 350 may each be connected to one or more antennas 316 and 356, respectively, for communicating with other network nodes, such as other UEs, access points, base stations (e.g., eNBs, gNBs), etc., via at least one designated RAT (e.g., NR, LTE, GSM, etc.) over a wireless communication medium of interest (e.g., some set of time/frequency resources in a particular frequency spectrum). The WWAN transceivers 310 and 350 may be variously configured for transmitting and encoding signals 318 and 358 (e.g., messages, indications, information, and so on), respectively, and, conversely, for receiving and decoding signals 318 and 358 (e.g., messages, indications, information, pilots, and so on), respectively, in accordance with the designated RAT. Specifically, the WWAN transceivers 310 and 350 include one or more transmitters 314 and 354, respectively, for transmitting and encoding signals 318 and 358, respectively, and one or more receivers 312 and 352, respectively, for receiving and decoding signals 318 and 358, respectively.

[0079] The UE 302 and the base station 304 each also include, at least in some cases, one or more short-range wireless transceivers 320 and 360, respectively. The short-range wireless transceivers 320 and 360 may be connected to one or more antennas 326 and 366, respectively, and provide means for communicating (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for refraining from transmitting, etc.) with other network nodes, such as other UEs, access points, base stations, etc., via at least one designated RAT (e.g., WiFi, LTE-D, Bluetooth®, Zigbee®, Z-Wave®, PC5, dedicated short-range communications (DSRC), wireless access for vehicular environments (WAVE), near-field communication (NFC), etc.) over a wireless communication medium of interest. The short-range wireless transceivers 320 and 360 may be variously configured for transmitting and encoding signals 328 and 368 (e.g., messages, indications, information, and so on), respectively, and, conversely, for receiving and decoding signals 328 and 368 (e.g., messages, indications, information, pilots, and so on), respectively, in accordance with the designated RAT. Specifically, the short-range wireless transceivers 320 and 360 include one or more transmitters 324 and 364, respectively, for transmitting and encoding signals 328 and 368, respectively, and one or more receivers 322 and 362, respectively, for receiving and decoding signals 328 and 368, respectively. As specific examples, the short-range wireless transceivers 320 and 360 may be WiFi transceivers, Bluetooth® transceivers, Zigbee® and/or Z-Wave® transceivers, NFC transceivers, or vehicle-to-vehicle (V2V) and/or vehicle-to-everything (V2X) transceivers.

[0080] The UE 302 and the base station 304 also include, at least in some cases, satellite signal receivers 330 and 370. The satellite signal receivers 330 and 370 may be connected to one or more antennas 336 and 376, respectively, and may provide means for receiving and/or measuring satellite positioning/communication signals 338 and 378, respectively. Where the satellite signal receivers 330 and 370 are satellite positioning system receivers, the satellite positioning/communication signals 338 and 378 may be global positioning system (GPS) signals, global navigation satellite system (GLONASS) signals, Galileo signals, Beidou signals, Indian Regional Navigation Satellite System (NAVIC), QuasiZenith Satellite System (QZSS), etc. Where the satellite signal receivers 330 and 370 are non-terrestrial network (NTN) receivers, the satellite positioning/communication signals 338 and 378 may be communication signals (e.g., carrying control and/or user data) originating from a 5G network. The satellite signal receivers 330 and 370 may comprise any suitable hardware and/or software for receiving and processing satellite positioning/communication signals 338 and 378, respectively. The satellite signal receivers 330 and 370 may request information and operations as appropriate from the other systems, and, at least in some cases, perform calculations to determine locations of the UE 302 and the base station 304, respectively, using measurements obtained by any suitable satellite positioning system algorithm.

[0081] The base station 304 and the network entity 306 each include one or more network transceivers 380 and 390, respectively, providing means for communicating (e.g., means for transmitting, means for receiving, etc.) with other network entities (e.g., other base stations 304, other network entities 306). For example, the base station 304 may employ the one or more network transceivers 380 to communicate with other base stations 304 or network entities 306 over one or more wired or wireless backhaul links. As another example, the network entity 306 may employ the one or more network transceivers 390 to communicate with one or more base station 304 over one or more wired or wireless backhaul links, or with other network entities 306 over one or more wired or wireless core network interfaces.

[0082] A transceiver may be configured to communicate over a wired or wireless link. A transceiver (whether a wired transceiver or a wireless transceiver) includes transmitter circuitry (e.g., transmitters 314, 324, 354, 364) and receiver circuitry (e.g., receivers 312, 322, 352, 362). A transceiver may be an integrated device (e.g., embodying transmitter circuitry and receiver circuitry in a single device) in some implementations, may comprise separate transmitter circuitry and separate receiver circuitry in some implementations, or may be embodied in other ways in other implementations. The transmitter circuitry and receiver circuitry of a wired transceiver (e.g., network transceivers 380 and 390 in some implementations) may be coupled to one or more wired network interface ports. Wireless transmitter circuitry (e.g., transmitters 314, 324, 354, 364) may include or be coupled to a plurality of antennas (e.g., antennas 316, 326, 356, 366), such as an antenna array, that permits the respective apparatus (e.g., UE 302, base station 304) to perform transmit “beamforming,” as described herein. Similarly, wireless receiver circuitry (e.g., receivers 312, 322, 352, 362) may include or be coupled to a plurality of antennas (e.g., antennas 316, 326, 356, 366), such as an antenna array, that permits the respective apparatus (e.g., UE 302, base station 304) to perform receive beamforming, as described herein. In an aspect, the transmitter circuitry and receiver circuitry may share the same plurality of antennas (e.g., antennas 316, 326, 356, 366), such that the respective apparatus can only receive or transmit at a given time, not both at the same time. A wireless transceiver (e.g., WWAN transceivers 310 and 350, short-range wireless transceivers 320 and 360) may also include a network listen module (NLM) or the like for performing various measurements.

[0083] As used herein, the various wireless transceivers (e.g., transceivers 310, 320, 350, and 360, and network transceivers 380 and 390 in some implementations) and wired transceivers (e.g., network transceivers 380 and 390 in some implementations) may generally be characterized as “a transceiver,” “at least one transceiver,” or “one or more transceivers.” As such, whether a particular transceiver is a wired or wireless transceiver may be inferred from the type of communication performed. For example, backhaul communication between network devices or servers will generally relate to signaling via a wired transceiver, whereas wireless communication between a UE (e.g., UE 302) and a base station (e.g., base station 304) will generally relate to signaling via a wireless transceiver.

[0084] The UE 302, the base station 304, and the network entity 306 also include other components that may be used in conjunction with the operations as disclosed herein. The UE 302, the base station 304, and the network entity 306 include one or more processors 332, 384, and 394, respectively, for providing functionality relating to, for example, wireless communication, and for providing other processing functionality. The processors 332, 384, and 394 may therefore provide means for processing, such as means for determining, means for calculating, means for receiving, means for transmitting, means for indicating, etc. In an aspect, the processors 332, 384, and 394 may include, for example, one or more general purpose processors, multi-core processors, central processing units (CPUs), ASICs, digital signal processors (DSPs), field programmable gate arrays (FPGAs), other programmable logic devices or processing circuitry, or various combinations thereof.

[0085] The UE 302, the base station 304, and the network entity 306 include memory circuitry implementing memories 340, 386, and 396 (e.g., each including a memory device), respectively, for maintaining information (e.g., information indicative of reserved resources, thresholds, parameters, and so on). The memories 340, 386, and 396 may therefore provide means for storing, means for retrieving, means for maintaining, etc. In some cases, the UE 302, the base station 304, and the network entity 306 may include positioning component 342, 388, and 398, respectively. The positioning component 342, 388, and 398 may be hardware circuits that are part of or coupled to the processors 332, 384, and 394, respectively, that, when executed, cause the UE 302, the base station 304, and the network entity 306 to perform the functionality described herein. In other aspects, the positioning component 342, 388, and 398 may be external to the processors 332, 384, and 394 (e.g., part of a modem processing system, integrated with another processing system, etc.). Alternatively, the positioning component 342, 388, and 398 may be memory modules stored in the memories 340, 386, and 396, respectively, that, when executed by the processors 332, 384, and 394 (or a modem processing system, another processing system, etc.), cause the UE 302, the base station 304, and the network entity 306 to perform the functionality described herein. FIG. 3A illustrates possible locations of the positioning component 342, which may be, for example, part of the one or more WWAN transceivers 310, the memory 340, the one or more processors 332, or any combination thereof, or may be a standalone component. FIG. 3B illustrates possible locations of the positioning component 388, which may be, for example, part of the one or more WWAN transceivers 350, the memory 386, the one or more processors 384, or any combination thereof, or may be a standalone component. FIG. 3C illustrates possible locations of the positioning component 398, which may be, for example, part of the one or more network transceivers 390, the memory 396, the one or more processors 394, or any combination thereof, or may be a standalone component.

[0086] The UE 302 may include one or more sensors 344 coupled to the one or more processors 332 to provide means for sensing or detecting movement and/or orientation information that is independent of motion data derived from signals received by the one or more WWAN transceivers 310, the one or more short-range wireless transceivers 320, and/or the satellite signal receiver 330. By way of example, the sensor(s) 344 may include an accelerometer (e.g., a micro-electrical mechanical systems (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometric pressure altimeter), and/or any other type of movement detection sensor. Moreover, the sensor(s) 344 may include a plurality of different types of devices and combine their outputs in order to provide motion information. For example, the sensor(s) 344 may use a combination of a multi-axis accelerometer and orientation sensors to provide the ability to compute positions in two-dimensional (2D) and/or three-dimensional (3D) coordinate systems.

[0087] In addition, the UE 302 includes a user interface 346 providing means for providing indications (e.g., audible and/or visual indications) to a user and/or for receiving user input (e.g., upon user actuation of a sensing device such a keypad, a touch screen, a microphone, and so on). Although not shown, the base station 304 and the network entity 306 may also include user interfaces.

[0088] Referring to the one or more processors 384 in more detail, in the downlink, IP packets from the network entity 306 may be provided to the processor 384. The one or more processors 384 may implement functionality for an RRC layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The one or more processors 384 may provide RRC layer functionality associated with broadcasting of system information (e.g., master information block (MIB), system information blocks (SIBs)), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-RAT mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression/decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through automatic repeat request (ARQ), concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization.

[0089] The transmitter 354 and the receiver 352 may implement Layer-1 (LI) functionality associated with various signal processing functions. Layer-1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The transmitter 354 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an orthogonal frequency division multiplexing (OFDM) subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM symbol stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 302. Each spatial stream may then be provided to one or more different antennas 356. The transmitter 354 may modulate an RF carrier with a respective spatial stream for transmission.

[0090] At the UE 302, the receiver 312 receives a signal through its respective antenna(s) 316. The receiver 312 recovers information modulated onto an RF carrier and provides the information to the one or more processors 332. The transmitter 314 and the receiver 312 implement Layer- 1 functionality associated with various signal processing functions. The receiver 312 may perform spatial processing on the information to recover any spatial streams destined for the UE 302. If multiple spatial streams are destined for the UE 302, they may be combined by the receiver 312 into a single OFDM symbol stream. The receiver 312 then converts the OFDM symbol stream from the time-domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 304. These soft decisions may be based on channel estimates computed by a channel estimator. The soft decisions are then decoded and de-interleaved to recover the data and control signals that were originally transmitted by the base station 304 on the physical channel. The data and control signals are then provided to the one or more processors 332, which implements Layer-3 (L3) and Layer-2 (L2) functionality.

[0091] In the uplink, the one or more processors 332 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the core network. The one or more processors 332 are also responsible for error detection.

[0092] Similar to the functionality described in connection with the downlink transmission by the base station 304, the one or more processors 332 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression/decompression, and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ), priority handling, and logical channel prioritization.

[0093] Channel estimates derived by the channel estimator from a reference signal or feedback transmitted by the base station 304 may be used by the transmitter 314 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the transmitter 314 may be provided to different antenna(s) 316. The transmitter 314 may modulate an RF carrier with a respective spatial stream for transmission.

[0094] The uplink transmission is processed at the base station 304 in a manner similar to that described in connection with the receiver function at the UE 302. The receiver 352 receives a signal through its respective antenna(s) 356. The receiver 352 recovers information modulated onto an RF carrier and provides the information to the one or more processors 384.

[0095] In the uplink, the one or more processors 384 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 302. IP packets from the one or more processors 384 may be provided to the core network. The one or more processors 384 are also responsible for error detection.

[0096] For convenience, the UE 302, the base station 304, and/or the network entity 306 are shown in FIGS. 3A, 3B, and 3C as including various components that may be configured according to the various examples described herein. It will be appreciated, however, that the illustrated components may have different functionality in different designs. In particular, various components in FIGS. 3A to 3C are optional in alternative configurations and the various aspects include configurations that may vary due to design choice, costs, use of the device, or other considerations. For example, in case of FIG. 3A, a particular implementation of UE 302 may omit the WWAN transceiver(s) 310 (e.g., a wearable device or tablet computer or PC or laptop may have Wi-Fi and/or Bluetooth capability without cellular capability), or may omit the short-range wireless transceiver(s) 320 (e.g., cellular-only, etc.), or may omit the satellite signal receiver 330, or may omit the sensor(s) 344, and so on. In another example, in case of FIG. 3B, a particular implementation of the base station 304 may omit the WWAN transceiver(s) 350 (e.g., a Wi-Fi “hotspot” access point without cellular capability), or may omit the short-range wireless transceiver(s) 360 (e.g., cellular-only, etc.), or may omit the satellite receiver 370, and so on. For brevity, illustration of the various alternative configurations is not provided herein, but would be readily understandable to one skilled in the art.

[0097] The various components of the UE 302, the base station 304, and the network entity 306 may be communicatively coupled to each other over data buses 334, 382, and 392, respectively. In an aspect, the data buses 334, 382, and 392 may form, or be part of, a communication interface of the UE 302, the base station 304, and the network entity 306, respectively. For example, where different logical entities are embodied in the same device (e.g., gNB and location server functionality incorporated into the same base station 304), the data buses 334, 382, and 392 may provide communication between them.

[0098] The components of FIGS. 3 A, 3B, and 3C may be implemented in various ways. In some implementations, the components of FIGS. 3 A, 3B, and 3C may be implemented in one or more circuits such as, for example, one or more processors and/or one or more ASICs (which may include one or more processors). Here, each circuit may use and/or incorporate at least one memory component for storing information or executable code used by the circuit to provide this functionality. For example, some or all of the functionality represented by blocks 310 to 346 may be implemented by processor and memory component(s) of the UE 302 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). Similarly, some or all of the functionality represented by blocks 350 to 388 may be implemented by processor and memory component(s) of the base station 304 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). Also, some or all of the functionality represented by blocks 390 to 398 may be implemented by processor and memory component(s) of the network entity 306 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). For simplicity, various operations, acts, and/or functions are described herein as being performed “by a UE,” “by a base station,” “by a network entity,” etc. However, as will be appreciated, such operations, acts, and/or functions may actually be performed by specific components or combinations of components of the UE 302, base station 304, network entity 306, etc., such as the processors 332, 384, 394, the transceivers 310, 320, 350, and 360, the memories 340, 386, and 396, the positioning component 342, 388, and 398, etc.

[0099] In some designs, the network entity 306 may be implemented as a core network component. In other designs, the network entity 306 may be distinct from a network operator or operation of the cellular network infrastructure (e.g., NG RAN 220 and/or 5GC 210/260). For example, the network entity 306 may be a component of a private network that may be configured to communicate with the UE 302 via the base station 304 or independently from the base station 304 (e.g., over a non-cellular communication link, such as WiFi).

[0100] NR supports, or enables, various sidelink positioning techniques. FIG. 4A illustrates various scenarios of interest for sidelink-only or joint Uu and sidelink positioning, according to aspects of the disclosure. In scenario 410, at least one peer UE with a known location can improve the Uu-based positioning (e.g., multi-cell round-trip-time (RTT), downlink time difference of arrival (DL-TDOA), etc.) of a target UE by providing an additional anchor (e.g., using sidelink RTT (SL-RTT)). In scenario 420, a low-end (e.g., reduced capacity, or “RedCap”) target UE may obtain the assistance of premium UEs to determine its location using, e.g., sidelink positioning and ranging procedures with the premium UEs. Compared to the low-end UE, the premium UEs may have more capabilities, such as more sensors, a faster processor, more memory, more antenna elements, higher transmit power capability, access to additional frequency bands, or any combination thereof. In scenario 430, a relay UE (e.g., with a known location) participates in the positioning estimation of a remote UE without performing uplink positioning reference signal (PRS) transmission over the Uu interface. Scenario 440 illustrates the joint positioning of multiple UEs. Specifically, in scenario 440, two UEs with unknown positions can be jointly located in non-line-of-sight (NLOS) conditions by utilizing constraints from nearby UEs.

[0101] FIG. 4B illustrates additional scenarios of interest for sidelink-only or joint Uu and sidelink positioning, according to aspects of the disclosure. In scenario 450, UEs used for public safety (e.g., by police, firefighters, and/or the like) may perform peer-to-peer (P2P) positioning and ranging for public safety and other uses. For example, in scenario 450, the public safety UEs may be out of coverage of a network and determine a location or a relative distance and a relative position among the public safety UEs using sidelink positioning techniques. Similarly, scenario 460 shows multiple UEs that are out of coverage and determine a location or a relative distance and a relative position using sidelink positioning techniques, such as SL-RTT.

[0102] Sidelink communication takes place in transmission or reception resource pools. In the frequency domain, the minimum resource allocation unit is a sub-channel (e.g., a collection of consecutive PRBs in the frequency domain). In the time domain, resource allocation is in one slot intervals. However, some slots are not available for sidelink, and some slots contain feedback resources. In addition, sidelink resources can be (pre)configured to occupy fewer than the 14 symbols of a slot.

[0103] Sidelink resources are configured at the radio resource control (RRC) layer. The RRC configuration can be by pre-configuration (e.g., preloaded on the UE) or configuration (e.g., from a serving base station).

[0104] NR sidelinks support hybrid automatic repeat request (HARQ) retransmission. FIG. 5A is a diagram 500 of an example slot structure without feedback resources, according to aspects of the disclosure. In the example of FIG. 5 A, time is represented horizontally and frequency is represented vertically. In the time domain, the length of each block is one orthogonal frequency division multiplexing (OFDM) symbol, and the 14 symbols make up a slot. In the frequency domain, the height of each block is one sub-channel. Currently, the (pre)configured sub-channel size can be selected from the set of {10, 15, 20, 25, 50, 75, 100} physical resource blocks (PRBs).

[0105] For a sidelink slot, the first symbol is a repetition of the preceding symbol and is used for automatic gain control (AGC) setting. This is illustrated in FIG. 5A by the vertical and horizontal hashing. As shown in FIG. 5A, for sidelink, the physical sidelink control channel (PSCCH) and the physical sidelink shared channel (PSSCH) are transmitted in the same slot. Similar to the physical downlink control channel (PDCCH), the PSCCH carries sidelink control information (SCI) about sidelink resource allocation and descriptions about sidelink data transmitted to the UE. Likewise, similar to the physical downlink shared channel (PDSCH), the PSSCH carries user date for the UE. In the example of FIG. 5 A, the PSCCH occupies half the bandwidth of the sub-channel and only three symbols. Finally, a gap symbol is present after the PSSCH.

[0106] FIG. 5B is a diagram 550 of an example slot structure with feedback resources, according to aspects of the disclosure. In the example of FIG. 5B, time is represented horizontally and frequency is represented vertically. In the time domain, the length of each block is one OFDM symbol, and the 14 symbols make up a slot. In the frequency domain, the height of each block is one sub-channel.

[0107] The slot structure illustrated in FIG. 5B is similar to the slot structure illustrated in FIG. 5A, except that the slot structure illustrated in FIG. 5B includes feedback resources. Specifically, two symbols at the end of the slot have been dedicated to the physical sidelink feedback channel (PSFCH). The first PSFCH symbol is a repetition of the second PSFCH symbol for AGC setting. In addition to the gap symbol after the PSSCH, there is a gap symbol after the two PSFCH symbols. Currently, resources for the PSFCH can be configured with a periodicity selected from the set of {0, 1, 2, 4} slots.

[0108] Another aspect of sidelink positioning is the configuration of sidelink resource pools for positioning (RP-Ps). The 12 symbols between the first symbol of a sidelink slot (for AGC) and the last symbol (the gap) in the time domain and the allocated subchannel(s) in the frequency domain form a resource pool for sidelink transmission and/or reception. An RP-P can be configured within a resource pool specifically for positioning purposes. Each RP-P includes an offset, periodicity, number of consecutive symbols within a slot (e.g., as few as one symbol), and/or the bandwidth within a component carrier (or the bandwidth across multiple component carriers). In addition, each RP-P can be associated with a zone or a distance from a reference location.

[0109] A base station (or a UE) can assign, to another UE, one or more resource configurations from the RP-Ps. Additionally or alternatively, a UE (e.g., a relay or a remote UE) can request one or more RP-P configurations, and it can include in the request one or more of the following: (1) its location information (or zone identifier), (2) periodicity, (3) bandwidth, (4) offset, (5) number of symbols, and (6) whether a configuration with “low interference” is needed (which can be determined through an assigned quality of service (QoS) or priority).

[0110] A base station or a UE can configure/assign rate matching resources or RP-P for rate matching and/or muting to a sidelink UE such that when a collision exists between the assigned resources and another resource pool that contains data (PSSCH) and/or control (PSCCH), the sidelink UE is expected to rate match, mute, and/or puncture the data, DMRS, and/or CSI-RS within the colliding resources. This would enable orthogonalization between positioning and data transmissions for increased coverage of PRS signals.

[0111] FIG. 6 is a diagram 600 illustrating an example of a resource pool for positioning within a sidelink resource pool, according to aspects of the disclosure. In the example of FIG. 6, time is represented horizontally and frequency is represented vertically. In the time domain, the length of each block is an orthogonal frequency division multiplexing (OFDM) symbol, and the 14 symbols make up a slot. In the frequency domain, the height of each block is a sub-channel.

[0112] In the example of FIG. 6, the entire slot (except for the first and last symbols) can be a resource pool for sidelink transmission and/or reception. That is, any of the symbols other than the first and last can be allocated for transmission and/or reception. However, an RP-P for sidelink transmission/reception is allocated in the last four pre-gap symbols of the slot. As such, non-sidelink positioning data, such as user data, CSI-RS, and control information, can only be transmitted in the first eight post-AGC symbols and not in the last four pre-gap symbols to prevent a collision with the configured RP-P. The non- sidelink positioning data that would otherwise be transmitted in the last four pre-gap symbols can be punctured or muted, or the non-sidelink data that would normally span more than the eight post-AGC symbols can be rate matched to fit into the eight post-AGC symbols.

[0113] Sidelink positioning reference signals (SL-PRS) have been defined to enable sidelink positioning procedures among UEs. Like a downlink PRS (DL-PRS), an SL-PRS resource is composed of one or more resource elements (i.e., one OFDM symbol in the time domain and one subcarrier in the frequency domain). SL-PRS resources have been designed with a comb-based pattern to enable fast Fourier transform (FFT)-based processing at the receiver. SL-PRS resources are composed of unstaggered, or only partially staggered, resource elements in the frequency domain to provide small time of arrival (TOA) uncertainty and reduced overhead of each SL-PRS resource. SL-PRS may also be associated with specific RP-Ps (e.g., certain SL-PRS may be allocated in certain RP-Ps). SL-PRS have also been defined with intra-slot repetition (not shown in FIG. 6) to allow for combining gains (if needed). There may also be inter-UE coordination of RP-Ps to provide for dynamic SL-PRS and data multiplexing while minimizing SL-PRS collisions.

[0114] FIG. 7 is a diagram 700 illustrating additional aspects of sidelink resource pools and resource pools for positioning, according to aspects of the disclosure. Specifically, diagram 700 illustrates a hierarchy of configuration parameters for sidelink communication resources that may be utilized by two or more sidelink UEs. As shown in FIG. 7, there are two resource pool configurations, a resource pool configuration for communication and a resource pool for positioning configuration (i.e., an RP-P configuration). The RP-P configuration is indicated by dashed boxes.

[0115] As shown in FIG. 7, an RP-P configuration indicates the subcarrier spacing (SCS), bandwidth (BW), and location for transmission (Tx) and reception (Rx) resource pools. The Tx resource pool(s) may be one or more Tx resource pools for Mode 1 resource allocation (where a base station allocates resources for sidelink communication) and/or Mode 2 resource allocation (where the involved UEs negotiate resource allocation for sidelink communication).

[0116] Each configured resource pool indicates the PSCCH used to reserve one or more SL-PRS configurations, the parameters of the one or more SL-PRS configurations, the channel busy ratio (CBR), the channel sensing configuration (for collision avoidance), and the transmit power control. The one or more SL-PRS configurations within the resource pool specify the number of symbols occupied by the SL-PRS, the comb type of the SL-PRS, the comb offset of the SL-PRS, the number of subchannels occupied by the SL-PRS, the subchannel size, and the starting resource block (RB).

[0117] Note that in FIG. 7, “CP” stands for “cyclic prefix,” “BWP” stands for “bandwidth part,” and “MCS” stands for “modulation and coding scheme.”

[0118] To reduce collisions (interference) among sidelink transmissions by different UEs, two inter-UE coordination schemes have been introduced. In both schemes, a first UE (referred to herein as “UE-A”) transmits coordination information to a second UE (referred to herein as “UE-B”) to assist the second UE in selecting resources for sidelink transmission. UE-A may observe channel conditions (e.g., CBR), resource allocations, control information (e.g., sidelink control information (SCI) broadcasted by other UEs), and/or the like, and then transmit coordination information to UE-B based on the observations.

[0119] For the first scheme, the coordination information may indicate preferred resources and non-preferred resources for UE-B to use for sidelink transmission. UE-B may then select transmission resources based on both its own channel sensing results and the coordination information. Alternatively, UE-B may select transmission resources based only on the coordination information. Alternatively, UE-B may select transmission resources based on its own channel sensing results, and then reselect transmission resources based on the coordination information, as needed.

[0120] For the second scheme, the coordination information may indicate a future conflict (collision). FIG. 8 is a diagram 800 illustrating how a UE can determine a future conflict among scheduled (reserved) sidelink transmission resources, according to aspects of the disclosure. Each block represents some set of time and frequency resources allocated for sidelink communication. For example, each block may represent one slot in the time domain (the horizontal axis) and one subchannel in the frequency domain (the vertical axis). As shown in FIG. 8, a first UE (labeled “UE0”) broadcasts SCI in a first block of resources and a second UE (labeled “UE1”) broadcasts SCI in a second block of resources. The SCI from both UEs indicates that both UEs intend to transmit in the same future block of resources (i.e., they are both reserving the same future block of transmission resources). By decoding the SCI from both UEs, UE-A can determine that there will be a future conflict at the indicated block of resources. UE-A can then transmit an indication of the expected/potential resource conflict to UE-B.

[0121] UE-B may be UE0, UE1, or another UE. In the example of FIG. 8, UE-B is UE1. In response to the expected conflict indication from UE-A, UE1 may determine not to transmit at the conflicting resource location (as indicated by the “X”), and instead, reselect (re-reserve) different sidelink resources for the transmission.

[0122] In an aspect, UE-A may be limited by configuration or pre-configuration to transmit the conflict indication to only the UE(s) from which UE-A intends/expects to receive a sidelink transmission. Thus, where UE-B is one of UE0 and UE1 in FIG. 8, UE-A would be the intended recipient of one of the conflicting transmissions illustrated in FIG. 8, and would transmit the conflict indication to the respective UE. [0123] There are various conditions that may indicate a potential conflict among scheduled (reserved) transmission resources. As a first condition, there are various options that may indicate whether UE-B’s resource reservation will overlap with another UE’s resource reservation (or transmission) for the same set of resources. For example, as a first option, the other UE’s reservation may have an RSRP above a threshold. As a second option, the other UE’s reservation and UE-B’s reservation may have an RSRP difference within a threshold. As a third option, the other UE and UE-B may be within a distance threshold of each other. As a fourth option, the other UE’s reservation and UE-B’s reservation may have an RSRP difference larger than a threshold. As a second condition, UE-A does not expect to receive UE-B’s reserved resource due to operating in half-duplex mode.

[0124] The present disclosure provides techniques for UE-A to provide a collision type indicator in the coordination information. In the present disclosure, SL-PRS resource conflicts may be one of two types of collisions. The first type of conflict (referred to as “Type 1”) is a partial or full overlap of the time and/or frequency resources being used (reserved) for two SL-PRS transmissions. In addition, for Type 1 conflicts, the SL-PRS use different scrambling identifiers (IDs). As such, a colliding SL-PRS will just be noise to the receiver (e g., UE-A).

[0125] The second type of conflict (referred to as “Type 2”) is a partial or full overlap of the time and/or frequency resources being used (reserved) for two SL-PRS transmissions. However, for Type 2 conflicts, the SL-PRS use the same scrambling ID. Note that both the first and second types of conflicts may each be subdivided into two sub-types. Specifically, they may be divided into a partial overlap conflict and a full overlap conflict.

[0126] For pre-collision detection (as illustrated in FIG. 8), UE-A can decode the SCIs scheduling the colliding transmissions and determine whether there is a Type 1 or Type 2 collision.

[0127] Consider the following scenario. A first UE (referred to as “UE1”) is transmitting SL- PRS with transmit power “Pl” and a second UE (referred to as “UE2”) is transmitting SL-PRS with transmit power “P2.” Both the UE1 and UE2 SL-PRS transmissions will collide at (i.e., from the perspective of) a third UE (referred to as “UE3”). UE3 will be able to decode the UE1 SL-PRS transmission if P1/(P2 + n) is greater than a threshold, where n is the noise at the receiver (i.e., UE3). UE3 will be able to decode the UE2 SL- PRS transmission if P2/(P1 + n) is greater than a threshold. [0128] In an aspect, UE-A may provide a collision metric in the coordination information. The collision metric may be a function of RSRP. For pre-collision conflict detection (as illustrated in FIG. 8), the RSRP of the SCI from different UEs can be used. For postcollision conflict detection, the signal-to-noise ratio (SNR) and RSRP of the SL-PRS can be used. UE-A will determine the difference in RSRP or RSRP and/or SNR and map it to a predefined metric table. An example table is illustrated below:

Table 1

[0129] UE-A may include in the collision report (in the coordination information) the type of collision (e.g., Type 1 or Type 2) and the collision metric (e.g., a value from 0 to 4). In an aspect, UE-A may be configured to report only collisions of a specific type (e.g., Type 2), or collisions associated with a collision metric more than a predefined/configured threshold (e.g., greater than 1 from Table 1).

[0130] FIG. 9 is a diagram 900 illustrating a past conflict among sidelink transmission resources, according to aspects of the disclosure. Each block represents some set of time and frequency resources allocated for sidelink communication. For example, each block may represent one slot in the time domain (the horizontal axis) and one subchannel in the frequency domain (the vertical axis). As shown in FIG. 9, as in FIG. 8, a first UE (labeled “UE0”) broadcasts SCI in a first block of resources and a second UE (labeled “UE1”) broadcasts SCI in a second block of resources. The SCI from both UEs indicates that both UEs will transmit in the same future block of resources (i.e., they are both reserving the same future block of transmission resources). The UEs then transmit in the indicated block of resources, resulting in a collision. After the collision, UE-A can determine that there was a collision at the indicated block of resources based on the SNR and/or RSRP of the transmissions from UE0 and UE1, as described above. UE-A can then transmit an indication of the past resource conflict to UE-B (UE0, UE1, or another UE). [0131] Collisions of SL-PRS resources between different UEs depend on the bandwidth, transmit power, and the number of UEs transmitting at the same time. Referring to additional aspects of the collision metric described above, a location server (e.g., LMF 270) can control the collision metric to define a SL-PRS collision. For example, consider a first case for 100 MHz positioning signals (e.g., SL-PRS). If one signal is very strong compared to the other signal, the weaker signal will be buried in the noise and interfere with the stronger signal. Thus, a collision may only be considered to occur if the difference in signal strength (e.g., RSRP, SNR) between the colliding positioning signals is greater than X dB. In contrast, for a second case, for 20 MHz positioning signals, a collision may only be considered to occur if the difference in signal strength (e.g., RSRP, SNR) between the colliding positioning signals is greater than Y dB.

[0132] If the location server configures a collision metric as X dB, then a UE (e.g., UE-A) will consider two transmission resources as colliding/conflicting if the difference in their signal strength metrics (e.g., RSRP, SNR) is greater than X dB. A UE will consider two transmission resources as not colliding/conflicting even if they overlap in time and/or frequency if the difference in their signal strength metrics is less than X dB.

[0133] However, a UE capable of successive interference cancellation (SlC)Zadvance processing, may be able to decode both transmission resources if the difference between their signal strength metrics (e.g., RSRP, SNR) is greater than Y dB. That is, by first decoding the highest power signal and then subtracting that decoded signal from the received signal, the UE will be able to decode the second signal.

[0134] The present disclosure further provides techniques for aperiodic SL-PRS resource conflict management. Aperiodic SL-PRS transmissions are SL-PRS transmissions that are made on-demand, or upon request, of some entity (e.g., the transmitting UE, a recipient UE, a network entity, etc.). The transmitting UE may reserve one or more SL-PRS occasions (or transmission opportunities or instances) in which to transmit one or more repetitions of the requested SL-PRS.

[0135] FIG. 10 is a diagram 1000 illustrating an example scenario in which a UE has reserved three opportunities for the transmission of a specific SL-PRS resource, according to aspects of the disclosure. For example, the three transmission opportunities (occasions) may be three slots in which the UE may transmit subsequent repetitions of the same SL- PRS resource. In the example of FIG. 10, it is assumed that there is a large enough gap between the reserved transmission opportunities that there may be other sidelink transmissions on the sidelink channel between the reserved opportunities. The number of reserved transmission opportunities (three in the example of FIG. 10) may be predetermined, configured, a UE capability, application-dependent, or configured by the location server or base station (or other network entity).

[0136] A series of reservations for an SL-PRS resource, such as the three reservations illustrated in FIG. 10, may include “hard” and “soft” reservations. A hard reservation is a reservation during which the UE will transmit an SL-PRS resource regardless of feedback from the recipient UE. A soft reservation is a reservation during which the UE may transmit a repetition of the SL-PRS resource, depending on the feedback from the recipient UE for the previous repetition of the SL-PRS resource. The first reservation illustrated in each scenario in FIG. 10 is a hard reservation, since the UE will transmit that SL-PRS repetition regardless of any feedback from the recipient UE (because there is none). The second two reservations are soft reservations because the UE transmits or refrains from transmitting the two remaining repetitions of the SL-PRS resource depending on feedback from the recipient UE.

[0137] More specifically, FIG. 10 illustrates two example retransmission request scenarios in which the UE determines whether to transmit additional repetitions of the SL-PRS resource on the remaining two soft resources. In the first scenario (labeled “Case 1”), the UE transmits an SL-PRS resource repetition in the first reserved occasion (the first reserved occasion is a hard reservation). However, because the UE does not receive a request to transmit a subsequent repetition of the SL-PRS resource, it does not transmit additional repetitions of the SL-PRS resource in the remaining reservations. In the second scenario (labeled “Case 2”), the UE transmits an SL-PRS repetition in the two remaining occasions because, after transmission of each of the first two SL-PRS repetitions, the UE receives a request to transmit a subsequent repetition of the SL-PRS resource. In an aspect, the number of hard and/or soft reservations permitted may be configurable.

[0138] After the UE transmits the SL-PRS resource in the first SL-PRS opportunity illustrated in FIG. 10, there are a number of conditions under which the recipient UE may request retransmission of the SL-PRS resource (i.e., request transmission of a subsequent repetition of the SL-PRS resource). For example, if (1) the recipient UE does not decode the SL-PRS resource, (2) the signal quality of the SL-PRS resource is worse than a signal quality threshold, (3) the SNR of the SL-PRS resource is below an SNR threshold, (4) the RSRP of the SL-PRS resource is below an RSRP threshold, (5) there are too many multipaths (e.g., above a multipath threshold) of the SL-PRS resource, (6) there is a large delay spread (e.g., above a delay spread threshold), (7) there is a low confidence in the earliest time of arrival (TOA) estimate (e.g., below a ToA confidence threshold) of the SL-PRS resource, and/or (8) there is a low confidence in the angle-of-arrival (Ao A) (e.g., below an AoA confidence threshold) of the SL-PRS resource. If any one or more of these conditions are satisfied, then the recipient UE can send a retransmission request, a negative acknowledgment (NACK), or a “same-PRS request” to the transmitting UE, and the transmitting UE will retransmit the SL-PRS resource in the next reservation opportunity. Note that if the recipient UE does decode the SL-PRS resource, it does not send a retransmission request to the transmitting UE, and therefore, after some time threshold, the transmitting UE does not transmit the remaining repetitions.

[0139] The latest that a transmitting UE may be configured to expect a retransmission request for an SL-PRS resource repetition may be defined as (1) X symbols or slots before the transmission of the first repetition of the next SL-PRS or the SCI triggering that SL-PRS, (2) Y symbols or slots after the transmission of the previous (most recent) SL-PRS occasion (i.e., the SL-PRS repetition that is expected to be acknowledged), or (3) a UE capability for such timelines.

[0140] In an aspect, the number of soft repetitions/reservations that a UE may reserve may depend on (1) the priority of the positioning session and/or SL-PRS, (2) an application layer requirement, (3) the QoS, (4) the sensing report (of the sidelink channel), and/or (5) the CBR measurement(s). For example, a higher priority positioning session, a more congested channel, or a higher CBR may necessitate, or permit, more soft reservations.

[0141] A UE may also be able to perform soft reservations for the responding SL-PRS from another UE (e.g., the response signal in an RTT positioning procedure). For example, a UE may reserve X slots subject to the following approaches. As a first approach, some number of Y less than or equal to a total of X slots (or other time domain opportunity) may be reserved for the purpose of a first UE (referred to as “UE1”) transmitting SL-PRS. The first UE should therefore transmit a minimum of one and a maximum of Y repetitions of the SL-PRS resource. Next, some number Z less than or equal to X minus Y slots (or other time domain opportunity) may be reserved for the purpose of the second UE (referred to as “UE2”) transmitting SL-PRS in response to the SL-PRS from UE1. The second UE should transmit a minimum of one and a maximum of X minus Y repetitions. [0142] As a second approach, some number of Y less than or equal to X slots (or other time domain opportunity) may be reserved for the purpose of a first UE (referred to as “UE1”) transmitting SL-PRS. The first UE should therefore transmit a minimum of one and a maximum of Y repetitions of the SL-PRS resource. Eventually, K transmissions will be consumed. Next, some number Z less than or equal to X minus K slots (or other time domain opportunity) may be reserved for the purpose of the second UE (referred to as “UE2”) transmitting SL-PRS in response to the SL-PRS from UE1. In this case, the second UE should transmit a minimum of one and a maximum of X minus K repetitions.

[0143] FIG. 11 illustrates an example method 1100 of wireless communication, according to aspects of the disclosure. In an aspect, method 1100 may be performed by a UE (e.g., any of the UEs described herein).

[0144] At 1110, the UE detects a conflict between a first sidelink reference signal transmission from a first sidelink UE and a second sidelink reference signal transmission from a second sidelink UE, wherein the first sidelink reference signal transmission at least partially overlaps with the second sidelink reference signal transmission in at least one time resource, at least one frequency resource, or both. In an aspect, operation 1110 may be performed by the one or more transceivers 310, the one or more processors 332, memory 340, and/or positioning component 342, any or all of which may be considered means for performing this operation.

[0145] At 1120, the UE transmits a collision report to a third sidelink UE, the collision report including at least a collision type indicator indicating whether the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier. In an aspect, the third UE may be the first UE, the second UE, or another UE. In addition, the UE may transmit the collision report to more than one third UE (e.g., broadcast or groupcast). In an aspect, operation 1120 may be performed by the one or more transceivers 310, the one or more processors 332, memory 340, and/or positioning component 342, any or all of which may be considered means for performing this operation.

[0146] As will be appreciated, a technical advantage of the method 1100 is enabling the UE to provide more meaningful collision information to a target UE.

[0147] FIG. 12 illustrates an example method 1200 of wireless communication, according to aspects of the disclosure. In an aspect, method 1200 may be performed by a UE (e.g., any of the UEs described herein). [0148] At 1210, the UE transmits a reservation request to reserve a plurality of transmission occasions on a sidelink channel for transmission of a plurality of repetitions of an SL- PRS resource. In an aspect, operation 1210 may be performed by the one or more transceivers 310, the one or more processors 332, memory 340, and/or positioning component 342, any or all of which may be considered means for performing this operation.

[0149] At 1220, the UE transmits, to at least one recipient UE, a first repetition of the plurality of repetitions of the SL-PRS resource during a first transmission occasion of the plurality of transmission occasions. In an aspect, operation 1220 may be performed by the one or more transceivers 310, the one or more processors 332, memory 340, and/or positioning component 342, any or all of which may be considered means for performing this operation.

[0150] At 1230, the UE transmits or refrains from transmitting at least a second repetition of the plurality of repetitions of the SL-PRS resource during at least a second transmission occasion of the plurality of transmission occasions based on feedback or lack of feedback from the at least one recipient UE. In an aspect, operation 1230 may be performed by the one or more transceivers 310, the one or more processors 332, memory 340, and/or positioning component 342, any or all of which may be considered means for performing this operation.

[0151] As will be appreciated, a technical advantage of the method 1200 is improved resource utilization and greater flexibility, insofar as not all reserved repetitions of a SL-PRS resource may need to be transmitted.

[0152] In the detailed description above it can be seen that different features are grouped together in examples. This manner of disclosure should not be understood as an intention that the example clauses have more features than are explicitly mentioned in each clause. Rather, the various aspects of the disclosure may include fewer than all features of an individual example clause disclosed. Therefore, the following clauses should hereby be deemed to be incorporated in the description, wherein each clause by itself can stand as a separate example. Although each dependent clause can refer in the clauses to a specific combination with one of the other clauses, the aspect(s) of that dependent clause are not limited to the specific combination. It will be appreciated that other example clauses can also include a combination of the dependent clause aspect(s) with the subject matter of any other dependent clause or independent clause or a combination of any feature with other dependent and independent clauses. The various aspects disclosed herein expressly include these combinations, unless it is explicitly expressed or can be readily inferred that a specific combination is not intended (e.g., contradictory aspects, such as defining an element as both an electrical insulator and an electrical conductor). Furthermore, it is also intended that aspects of a clause can be included in any other independent clause, even if the clause is not directly dependent on the independent clause.

[0153] Implementation examples are described in the following numbered clauses:

[0154] Clause 1. A method of wireless communication performed by a user equipment (UE), comprising: detecting a conflict between a first sidelink reference signal transmission from a first sidelink UE and a second sidelink reference signal transmission from a second sidelink UE, wherein the first sidelink reference signal transmission at least partially overlaps with the second sidelink reference signal transmission in at least one time resource, at least one frequency resource, or both; and transmitting a collision report to a third sidelink UE, the collision report including at least a collision type indicator indicating whether the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier.

[0155] Clause 2. The method of clause 1, wherein the collision report further includes a collision metric.

[0156] Clause 3. The method of clause 2, wherein: the conflict is detected before transmission of the first sidelink reference signal transmission and the second sidelink reference signal transmission, and the collision metric indicates an expected difference in signal strength between the first sidelink reference signal transmission and the second sidelink reference signal transmission.

[0157] Clause 4. The method of clause 3, wherein the expected difference in signal strength is based on a first signal strength of first sidelink control information (SCI) from the first sidelink UE scheduling the first sidelink reference signal transmission and a second signal strength of second SCI from the second sidelink UE scheduling the second sidelink reference signal transmission.

[0158] Clause 5. The method of clause 4, wherein: the first signal strength is a first reference signal received power (RSRP) measurement, and the second signal strength is a second RSRP measurement.

[0159] Clause 6. The method of clause 2, wherein: the conflict is detected upon reception of the first sidelink reference signal transmission and the second sidelink reference signal transmission, and the collision metric indicates a difference in signal strength between the first sidelink reference signal transmission and the second sidelink reference signal transmission.

[0160] Clause 7. The method of clause 6, wherein the difference in signal strength is based on: a first signal-to-noise ratio (SNR) of the first sidelink reference signal transmission and a second SNR of the second sidelink reference signal transmission, a first RSRP of the first sidelink reference signal transmission and a second RSRP of the second sidelink reference signal transmission, or any combination thereof.

[0161] Clause 8. The method of any of clauses 2 to 7, wherein the collision report includes the collision metric based on the collision metric indicating a signal strength difference between the first sidelink reference signal transmission and the second sidelink reference signal transmission satisfying a threshold.

[0162] Clause 9. The method of clause 8, further comprising: receiving the threshold from a location server or a serving base station.

[0163] Clause 10. The method of any of clauses 1 to 9, wherein the UE is configured to transmit the collision report based on: the collision type indicator indicating that the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier, or the collision type indicator indicating that the first sidelink reference signal transmission and the second sidelink reference signal transmission have different scrambling identifiers.

[0164] Clause 11. The method of any of clauses 1 to 10, wherein the conflict is detected before transmission of the first sidelink reference signal transmission and the second sidelink reference signal transmission.

[0165] Clause 12. The method of any of clauses 1 to 11, wherein: the third sidelink UE is the first sidelink UE, the UE is an intended recipient of the first sidelink reference signal transmission, and the collision report is transmitted to the first sidelink UE based on the UE being the intended recipient of the first sidelink reference signal transmission.

[0166] Clause 13. The method of any of clauses 1 to 12, wherein: the conflict is detected before transmission of the first sidelink reference signal transmission and the second sidelink reference signal transmission, and detecting the conflict comprises: decoding first sidelink control information (SCI) from the first sidelink UE to determine first time resources, first frequency resources, or both on which the first sidelink reference signal transmission is scheduled to be transmitted; decoding second SCI from the second UE to determine second time resources, second frequency resources, or both on which the second sidelink reference signal transmission is scheduled to be transmitted; and determining that the first sidelink reference signal transmission and the second sidelink reference signal transmission overlap in the at least one time resource, the at least one frequency resource, or both based on a comparison of the first time resources, the first frequency resources, or both and the second time resources, the second frequency resources, or both.

[0167] Clause 14. The method of any of clauses 1 to 13, wherein: the first sidelink reference signal transmission is a first sidelink positioning reference signal (SL-PRS), and the second sidelink reference signal transmission is a second SL-PRS.

[0168] Clause 15. A method of wireless communication performed by a user equipment (UE), comprising: transmitting a reservation request to reserve a plurality of transmission occasions on a sidelink channel for transmission of a plurality of repetitions of a sidelink positioning reference signal (SL-PRS) resource; transmitting, to at least one recipient UE, a first repetition of the plurality of repetitions of the SL-PRS resource during a first transmission occasion of the plurality of transmission occasions; and transmitting or refraining from transmitting at least a second repetition of the plurality of repetitions of the SL-PRS resource during at least a second transmission occasion of the plurality of transmission occasions based on feedback or lack of feedback from the at least one recipient UE.

[0169] Clause 16. The method of clause 15, wherein: the feedback comprises a negative acknowledgment, a retransmission request, or a request to transmit SL-PRS, and transmitting or refraining from transmitting at least the second repetition comprises transmitting the second repetition during the second transmission occasion.

[0170] Clause 17. The method of clause 16, wherein the feedback comprises the negative acknowledgment, the retransmission request, or the request to transmit SL-PRS based on: the first repetition of the SL-PRS resource is not successfully decoded at the at least one recipient UE, a signal quality of the first repetition of the SL-PRS resource is below a signal quality threshold, a number of multipaths of the first repetition of the SL-PRS resource is above a multipath threshold, a delay spread of the first repetition of the SL- PRS resource is above a delay spread threshold, a confidence in an earliest time of arrival (To A) of the first repetition of the SL-PRS resource is below a ToA confidence threshold, a confidence in an angle-of-arrival (AoA) of the first repetition of the SL-PRS resource is below an AoA confidence threshold, or any combination thereof. [0171] Clause 18. The method of clause 15, wherein transmitting or refraining from transmitting at least the second repetition comprises: refraining from transmitting remaining repetitions of the plurality of repetitions based on lack of feedback from at least one recipient UE within a time threshold.

[0172] Clause 19. The method of any of clauses 15 to 18, further comprising: waiting for the feedback from the at least one recipient UE up to a configured time period before the second repetition or sidelink control information (SCI) scheduling the second repetition.

[0173] Clause 20. The method of any of clauses 15 to 19, further comprising: waiting for the feedback from the at least one recipient UE for a configured time period after the first repetition.

[0174] Clause 21. The method of any of clauses 15 to 20, wherein a number of remaining repetitions of the plurality of repetitions is based on: a priority of the SL-PRS resource, an application layer requirement of the UE, a quality of service (QoS) of the SL-PRS resource, a sensing report for the sidelink channel, a channel busy ratio (CBR) of the sidelink channel, a configuration from a network entity, or any combination thereof.

[0175] Clause 22. The method of any of clauses 15 to 21, further comprising: receiving a configuration of a number of remaining repetitions of the plurality of repetitions from a network entity.

[0176] Clause 23. The method of any of clauses 15 to 22, wherein: a set of Y repetitions of the plurality of repetitions is reserved for the UE to transmit the SL-PRS resource to the at least one recipient UE, a set of Z repetitions of the plurality of repetitions is reserved for the at least one recipient UE to transmit a response SL-PRS resource to the UE, and the set of Z repetitions is less than or equal to the plurality of repetitions minus the set of Y repetitions.

[0177] Clause 24. The method of any of clauses 15 to 23, wherein: a set of Y repetitions of the plurality of repetitions is reserved for the UE to transmit the SL-PRS resource to the at least one recipient UE, the SL-PRS resource is transmitted in a set of K repetitions of the set of Y repetitions, a set of Z repetitions of the plurality of repetitions is reserved for the at least one recipient UE to transmit a response SL-PRS resource to the UE, and the set of Z repetitions is less than or equal to the plurality of repetitions minus the set of K repetitions.

[0178] Clause 25. A user equipment (UE), comprising: a memory; at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: detect a conflict between a first sidelink reference signal transmission from a first sidelink UE and a second sidelink reference signal transmission from a second sidelink UE, wherein the first sidelink reference signal transmission at least partially overlaps with the second sidelink reference signal transmission in at least one time resource, at least one frequency resource, or both; and transmit, via the at least one transceiver, a collision report to a third sidelink UE, the collision report including at least a collision type indicator indicating whether the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier.

[0179] Clause 26. The UE of clause 25, wherein the collision report further includes a collision metric.

[0180] Clause 27. The UE of clause 26, wherein: the conflict is detected before transmission of the first sidelink reference signal transmission and the second sidelink reference signal transmission, and the collision metric indicates an expected difference in signal strength between the first sidelink reference signal transmission and the second sidelink reference signal transmission.

[0181] Clause 28. The UE of clause 27, wherein the expected difference in signal strength is based on a first signal strength of first sidelink control information (SCI) from the first sidelink UE scheduling the first sidelink reference signal transmission and a second signal strength of second SCI from the second sidelink UE scheduling the second sidelink reference signal transmission.

[0182] Clause 29. The UE of clause 28, wherein: the first signal strength is a first reference signal received power (RSRP) measurement, and the second signal strength is a second RSRP measurement.

[0183] Clause 30. The UE of clause 26, wherein: the conflict is detected upon reception of the first sidelink reference signal transmission and the second sidelink reference signal transmission, and the collision metric indicates a difference in signal strength between the first sidelink reference signal transmission and the second sidelink reference signal transmission.

[0184] Clause 31. The UE of clause 30, wherein the difference in signal strength is based on: a first signal-to-noise ratio (SNR) of the first sidelink reference signal transmission and a second SNR of the second sidelink reference signal transmission, a first RSRP of the first sidelink reference signal transmission and a second RSRP of the second sidelink reference signal transmission, or any combination thereof.

[0185] Clause 32. The UE of any of clauses 26 to 31, wherein the collision report includes the collision metric based on the collision metric indicating a signal strength difference between the first sidelink reference signal transmission and the second sidelink reference signal transmission satisfying a threshold.

[0186] Clause 33. The UE of clause 32, wherein the at least one processor is further configured to: receive, via the at least one transceiver, the threshold from a location server or a serving base station.

[0187] Clause 34. The UE of any of clauses 25 to 33, wherein the UE is configured to transmit the collision report based on: the collision type indicator indicating that the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier, or the collision type indicator indicating that the first sidelink reference signal transmission and the second sidelink reference signal transmission have different scrambling identifiers.

[0188] Clause 35. The UE of any of clauses 25 to 34, wherein the conflict is detected before transmission of the first sidelink reference signal transmission and the second sidelink reference signal transmission.

[0189] Clause 36. The UE of any of clauses 25 to 35, wherein: the third sidelink UE is the first sidelink UE, the UE is an intended recipient of the first sidelink reference signal transmission, and the collision report is transmitted to the first sidelink UE based on the UE being the intended recipient of the first sidelink reference signal transmission.

[0190] Clause 37. The UE of any of clauses 25 to 36, wherein: the conflict is detected before transmission of the first sidelink reference signal transmission and the second sidelink reference signal transmission, and the at least one processor configured to detect the conflict comprises the at least one processor configured to: decode first sidelink control information (SCI) from the first sidelink UE to determine first time resources, first frequency resources, or both on which the first sidelink reference signal transmission is scheduled to be transmitted; decode second SCI from the second UE to determine second time resources, second frequency resources, or both on which the second sidelink reference signal transmission is scheduled to be transmitted; and determine that the first sidelink reference signal transmission and the second sidelink reference signal transmission overlap in the at least one time resource, the at least one frequency resource, or both based on a comparison of the first time resources, the first frequency resources, or both and the second time resources, the second frequency resources, or both.

[0191] Clause 38. The UE of any of clauses 25 to 37, wherein: the first sidelink reference signal transmission is a first sidelink positioning reference signal (SL-PRS), and the second sidelink reference signal transmission is a second SL-PRS.

[0192] Clause 39. A user equipment (UE), comprising: a memory; at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: transmit, via the at least one transceiver, a reservation request to reserve a plurality of transmission occasions on a sidelink channel for transmission of a plurality of repetitions of a sidelink positioning reference signal (SL-PRS) resource; transmit, via the at least one transceiver, to at least one recipient UE, a first repetition of the plurality of repetitions of the SL-PRS resource during a first transmission occasion of the plurality of transmission occasions; and transmit, via the at least one transceiver, or refrain from transmitting at least a second repetition of the plurality of repetitions of the SL-PRS resource during at least a second transmission occasion of the plurality of transmission occasions based on feedback or lack of feedback from the at least one recipient UE.

[0193] Clause 40. The UE of clause 39, wherein: the feedback comprises a negative acknowledgment, a retransmission request, or a request to transmit SL-PRS, and the at least one processor configured to transmit or refrain from transmitting at least the second repetition comprises the at least one processor configured to transmit, via the at least one transceiver, the second repetition during the second transmission occasion.

[0194] Clause 41. The UE of clause 40, wherein the feedback comprises the negative acknowledgment, the retransmission request, or the request to transmit SL-PRS based on: the first repetition of the SL-PRS resource is not successfully decoded at the at least one recipient UE, a signal quality of the first repetition of the SL-PRS resource is below a signal quality threshold, a number of multipaths of the first repetition of the SL-PRS resource is above a multipath threshold, a delay spread of the first repetition of the SL- PRS resource is above a delay spread threshold, a confidence in an earliest time of arrival (To A) of the first repetition of the SL-PRS resource is below a ToA confidence threshold, a confidence in an angle-of-arrival (AoA) of the first repetition of the SL-PRS resource is below an AoA confidence threshold, or any combination thereof. [0195] Clause 42. The UE of clause 39, wherein the at least one processor configured to transmit or refrain from transmitting at least the second repetition comprises the at least one processor configured to: refrain from transmitting remaining repetitions of the plurality of repetitions based on lack of feedback from at least one recipient UE within a time threshold.

[0196] Clause 43. The UE of any of clauses 39 to 42, wherein the at least one processor is further configured to: wait for the feedback from the at least one recipient UE up to a configured time period before the second repetition or sidelink control information (SCI) scheduling the second repetition.

[0197] Clause 44. The UE of any of clauses 39 to 43, wherein the at least one processor is further configured to: wait for the feedback from the at least one recipient UE for a configured time period after the first repetition.

[0198] Clause 45. The UE of any of clauses 39 to 44, wherein a number of remaining repetitions of the plurality of repetitions is based on: a priority of the SL-PRS resource, an application layer requirement of the UE, a quality of service (QoS) of the SL-PRS resource, a sensing report for the sidelink channel, a channel busy ratio (CBR) of the sidelink channel, a configuration from a network entity, or any combination thereof.

[0199] Clause 46. The UE of any of clauses 39 to 45, wherein the at least one processor is further configured to: receive, via the at least one transceiver, a configuration of a number of remaining repetitions of the plurality of repetitions from a network entity.

[0200] Clause 47. The UE of any of clauses 39 to 46, wherein: a set of Y repetitions of the plurality of repetitions is reserved for the UE to transmit the SL-PRS resource to the at least one recipient UE, a set of Z repetitions of the plurality of repetitions is reserved for the at least one recipient UE to transmit a response SL-PRS resource to the UE, and the set of Z repetitions is less than or equal to the plurality of repetitions minus the set of Y repetitions.

[0201] Clause 48. The UE of any of clauses 39 to 47, wherein: a set of Y repetitions of the plurality of repetitions is reserved for the UE to transmit the SL-PRS resource to the at least one recipient UE, the SL-PRS resource is transmitted in a set of K repetitions of the set of Y repetitions, a set of Z repetitions of the plurality of repetitions is reserved for the at least one recipient UE to transmit a response SL-PRS resource to the UE, and the set of Z repetitions is less than or equal to the plurality of repetitions minus the set of K repetitions. [0202] Clause 49. A user equipment (UE), comprising: means for detecting a conflict between a first sidelink reference signal transmission from a first sidelink UE and a second sidelink reference signal transmission from a second sidelink UE, wherein the first sidelink reference signal transmission at least partially overlaps with the second sidelink reference signal transmission in at least one time resource, at least one frequency resource, or both; and means for transmitting a collision report to a third sidelink UE, the collision report including at least a collision type indicator indicating whether the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier.

[0203] Clause 50. The UE of clause 49, wherein the collision report further includes a collision metric.

[0204] Clause 51. The UE of clause 50, wherein: the conflict is detected before transmission of the first sidelink reference signal transmission and the second sidelink reference signal transmission, and the collision metric indicates an expected difference in signal strength between the first sidelink reference signal transmission and the second sidelink reference signal transmission.

[0205] Clause 52. The UE of clause 51, wherein the expected difference in signal strength is based on a first signal strength of first sidelink control information (SCI) from the first sidelink UE scheduling the first sidelink reference signal transmission and a second signal strength of second SCI from the second sidelink UE scheduling the second sidelink reference signal transmission.

[0206] Clause 53. The UE of clause 52, wherein: the first signal strength is a first reference signal received power (RSRP) measurement, and the second signal strength is a second RSRP measurement.

[0207] Clause 54. The UE of clause 50, wherein: the conflict is detected upon reception of the first sidelink reference signal transmission and the second sidelink reference signal transmission, and the collision metric indicates a difference in signal strength between the first sidelink reference signal transmission and the second sidelink reference signal transmission.

[0208] Clause 55. The UE of clause 54, wherein the difference in signal strength is based on: a first signal-to-noise ratio (SNR) of the first sidelink reference signal transmission and a second SNR of the second sidelink reference signal transmission, a first RSRP of the first sidelink reference signal transmission and a second RSRP of the second sidelink reference signal transmission, or any combination thereof.

[0209] Clause 56. The UE of any of clauses 50 to 55, wherein the collision report includes the collision metric based on the collision metric indicating a signal strength difference between the first sidelink reference signal transmission and the second sidelink reference signal transmission satisfying a threshold.

[0210] Clause 57. The UE of clause 56, further comprising: means for receiving the threshold from a location server or a serving base station.

[0211] Clause 58. The UE of any of clauses 49 to 57, wherein the UE is configured to transmit the collision report based on: the collision type indicator indicating that the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier, or the collision type indicator indicating that the first sidelink reference signal transmission and the second sidelink reference signal transmission have different scrambling identifiers.

[0212] Clause 59. The UE of any of clauses 49 to 58, wherein the conflict is detected before transmission of the first sidelink reference signal transmission and the second sidelink reference signal transmission.

[0213] Clause 60. The UE of any of clauses 49 to 59, wherein: the third sidelink UE is the first sidelink UE, the UE is an intended recipient of the first sidelink reference signal transmission, and the collision report is transmitted to the first sidelink UE based on the UE being the intended recipient of the first sidelink reference signal transmission.

[0214] Clause 61. The UE of any of clauses 49 to 60, wherein: the conflict is detected before transmission of the first sidelink reference signal transmission and the second sidelink reference signal transmission, and the means for detecting the conflict comprises: means for decoding first sidelink control information (SCI) from the first sidelink UE to determine first time resources, first frequency resources, or both on which the first sidelink reference signal transmission is scheduled to be transmitted; means for decoding second SCI from the second UE to determine second time resources, second frequency resources, or both on which the second sidelink reference signal transmission is scheduled to be transmitted; and means for determining that the first sidelink reference signal transmission and the second sidelink reference signal transmission overlap in the at least one time resource, the at least one frequency resource, or both based on a comparison of the first time resources, the first frequency resources, or both and the second time resources, the second frequency resources, or both.

[0215] Clause 62. The UE of any of clauses 49 to 61, wherein: the first sidelink reference signal transmission is a first sidelink positioning reference signal (SL-PRS), and the second sidelink reference signal transmission is a second SL-PRS.

[0216] Clause 63. A user equipment (UE), comprising: means for transmitting a reservation request to reserve a plurality of transmission occasions on a sidelink channel for transmission of a plurality of repetitions of a sidelink positioning reference signal (SL- PRS) resource; means for transmitting, to at least one recipient UE, a first repetition of the plurality of repetitions of the SL-PRS resource during a first transmission occasion of the plurality of transmission occasions; and means for transmitting or refraining from transmitting at least a second repetition of the plurality of repetitions of the SL-PRS resource during at least a second transmission occasion of the plurality of transmission occasions based on feedback or lack of feedback from the at least one recipient UE.

[0217] Clause 64. The UE of clause 63, wherein: the feedback comprises a negative acknowledgment, a retransmission request, or a request to transmit SL-PRS, and the means for transmitting or refraining from transmitting at least the second repetition comprises means for transmitting the second repetition during the second transmission occasion.

[0218] Clause 65. The UE of clause 64, wherein the feedback comprises the negative acknowledgment, the retransmission request, or the request to transmit SL-PRS based on: the first repetition of the SL-PRS resource is not successfully decoded at the at least one recipient UE, a signal quality of the first repetition of the SL-PRS resource is below a signal quality threshold, a number of multipaths of the first repetition of the SL-PRS resource is above a multipath threshold, a delay spread of the first repetition of the SL- PRS resource is above a delay spread threshold, a confidence in an earliest time of arrival (To A) of the first repetition of the SL-PRS resource is below a ToA confidence threshold, a confidence in an angle-of-arrival (AoA) of the first repetition of the SL-PRS resource is below an AoA confidence threshold, or any combination thereof.

[0219] Clause 66. The UE of clause 63, wherein the means for transmitting or refraining from transmitting at least the second repetition comprises: means for refraining from transmitting remaining repetitions of the plurality of repetitions based on lack of feedback from at least one recipient UE within a time threshold. [0220] Clause 67. The UE of any of clauses 63 to 66, further comprising: means for waiting for the feedback from the at least one recipient UE up to a configured time period before the second repetition or sidelink control information (SCI) scheduling the second repetition.

[0221] Clause 68. The UE of any of clauses 63 to 67, further comprising: means for waiting for the feedback from the at least one recipient UE for a configured time period after the first repetition.

[0222] Clause 69. The UE of any of clauses 63 to 68, wherein a number of remaining repetitions of the plurality of repetitions is based on: a priority of the SL-PRS resource, an application layer requirement of the UE, a quality of service (QoS) of the SL-PRS resource, a sensing report for the sidelink channel, a channel busy ratio (CBR) of the sidelink channel, a configuration from a network entity, or any combination thereof.

[0223] Clause 70. The UE of any of clauses 63 to 69, further comprising: means for receiving a configuration of a number of remaining repetitions of the plurality of repetitions from a network entity.

[0224] Clause 71. The UE of any of clauses 63 to 70, wherein: a set of Y repetitions of the plurality of repetitions is reserved for the UE to transmit the SL-PRS resource to the at least one recipient UE, a set of Z repetitions of the plurality of repetitions is reserved for the at least one recipient UE to transmit a response SL-PRS resource to the UE, and the set of Z repetitions is less than or equal to the plurality of repetitions minus the set of Y repetitions.

[0225] Clause 72. The UE of any of clauses 63 to 71, wherein: a set of Y repetitions of the plurality of repetitions is reserved for the UE to transmit the SL-PRS resource to the at least one recipient UE, the SL-PRS resource is transmitted in a set of K repetitions of the set of Y repetitions, a set of Z repetitions of the plurality of repetitions is reserved for the at least one recipient UE to transmit a response SL-PRS resource to the UE, and the set of Z repetitions is less than or equal to the plurality of repetitions minus the set of K repetitions.

[0226] Clause 73. A non-transitory computer-readable medium storing computer-executable instructions that, when executed by a user equipment (UE), cause the UE to: detect a conflict between a first sidelink reference signal transmission from a first sidelink UE and a second sidelink reference signal transmission from a second sidelink UE, wherein the first sidelink reference signal transmission at least partially overlaps with the second sidelink reference signal transmission in at least one time resource, at least one frequency resource, or both; and transmit a collision report to a third sidelink UE, the collision report including at least a collision type indicator indicating whether the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier.

[0227] Clause 74. The non-transitory computer-readable medium of clause 73, wherein the collision report further includes a collision metric.

[0228] Clause 75. The non-transitory computer-readable medium of clause 74, wherein: the conflict is detected before transmission of the first sidelink reference signal transmission and the second sidelink reference signal transmission, and the collision metric indicates an expected difference in signal strength between the first sidelink reference signal transmission and the second sidelink reference signal transmission.

[0229] Clause 76. The non-transitory computer-readable medium of clause 75, wherein the expected difference in signal strength is based on a first signal strength of first sidelink control information (SCI) from the first sidelink UE scheduling the first sidelink reference signal transmission and a second signal strength of second SCI from the second sidelink UE scheduling the second sidelink reference signal transmission.

[0230] Clause 77. The non-transitory computer-readable medium of clause 76, wherein: the first signal strength is a first reference signal received power (RSRP) measurement, and the second signal strength is a second RSRP measurement.

[0231] Clause 78. The non-transitory computer-readable medium of clause 74, wherein: the conflict is detected upon reception of the first sidelink reference signal transmission and the second sidelink reference signal transmission, and the collision metric indicates a difference in signal strength between the first sidelink reference signal transmission and the second sidelink reference signal transmission.

[0232] Clause 79. The non-transitory computer-readable medium of clause 78, wherein the difference in signal strength is based on: a first signal-to-noise ratio (SNR) of the first sidelink reference signal transmission and a second SNR of the second sidelink reference signal transmission, a first RSRP of the first sidelink reference signal transmission and a second RSRP of the second sidelink reference signal transmission, or any combination thereof.

[0233] Clause 80. The non-transitory computer-readable medium of any of clauses 74 to 79, wherein the collision report includes the collision metric based on the collision metric indicating a signal strength difference between the first sidelink reference signal transmission and the second sidelink reference signal transmission satisfying a threshold.

[0234] Clause 81. The non-transitory computer-readable medium of clause 80, further comprising computer-executable instructions that, when executed by the UE, cause the UE to: receive the threshold from a location server or a serving base station.

[0235] Clause 82. The non-transitory computer-readable medium of any of clauses 73 to 81, wherein the UE is configured to transmit the collision report based on: the collision type indicator indicating that the first sidelink reference signal transmission and the second sidelink reference signal transmission have the same scrambling identifier, or the collision type indicator indicating that the first sidelink reference signal transmission and the second sidelink reference signal transmission have different scrambling identifiers.

[0236] Clause 83. The non-transitory computer-readable medium of any of clauses 73 to 82, wherein the conflict is detected before transmission of the first sidelink reference signal transmission and the second sidelink reference signal transmission.

[0237] Clause 84. The non-transitory computer-readable medium of any of clauses 73 to 83, wherein: the third sidelink UE is the first sidelink UE, the UE is an intended recipient of the first sidelink reference signal transmission, and the collision report is transmitted to the first sidelink UE based on the UE being the intended recipient of the first sidelink reference signal transmission.

[0238] Clause 85. The non-transitory computer-readable medium of any of clauses 73 to 84, wherein: the conflict is detected before transmission of the first sidelink reference signal transmission and the second sidelink reference signal transmission, and the computerexecutable instructions that, when executed by the UE, cause the UE to detect the conflict comprises computer-executable instructions that, when executed by the UE, cause the UE to: decode first sidelink control information (SCI) from the first sidelink UE to determine first time resources, first frequency resources, or both on which the first sidelink reference signal transmission is scheduled to be transmitted; decode second SCI from the second UE to determine second time resources, second frequency resources, or both on which the second sidelink reference signal transmission is scheduled to be transmitted; and determine that the first sidelink reference signal transmission and the second sidelink reference signal transmission overlap in the at least one time resource, the at least one frequency resource, or both based on a comparison of the first time resources, the first frequency resources, or both and the second time resources, the second frequency resources, or both.

[0239] Clause 86. The non-transitory computer-readable medium of any of clauses 73 to 85, wherein: the first sidelink reference signal transmission is a first sidelink positioning reference signal (SL-PRS), and the second sidelink reference signal transmission is a second SL-PRS.

[0240] Clause 87. A non-transitory computer-readable medium storing computer-executable instructions that, when executed by an UE, cause the UE to: transmit a reservation request to reserve a plurality of transmission occasions on a sidelink channel for transmission of a plurality of repetitions of a sidelink positioning reference signal (SL-PRS) resource; transmit, to at least one recipient UE, a first repetition of the plurality of repetitions of the SL-PRS resource during a first transmission occasion of the plurality of transmission occasions; and transmit or refrain from transmitting at least a second repetition of the plurality of repetitions of the SL-PRS resource during at least a second transmission occasion of the plurality of transmission occasions based on feedback or lack of feedback from the at least one recipient UE.

[0241] Clause 88. The non-transitory computer-readable medium of clause 87, wherein: the feedback comprises a negative acknowledgment, a retransmission request, or a request to transmit SL-PRS, and the computer-executable instructions that, when executed by the UE, cause the UE to transmit or refrain from transmitting at least the second repetition comprise computer-executable instructions that, when executed by the UE, cause the UE to transmit the second repetition during the second transmission occasion.

[0242] Clause 89. The non-transitory computer-readable medium of clause 88, wherein the feedback comprises the negative acknowledgment, the retransmission request, or the request to transmit SL-PRS based on: the first repetition of the SL-PRS resource is not successfully decoded at the at least one recipient UE, a signal quality of the first repetition of the SL-PRS resource is below a signal quality threshold, a number of multipaths of the first repetition of the SL-PRS resource is above a multipath threshold, a delay spread of the first repetition of the SL-PRS resource is above a delay spread threshold, a confidence in an earliest time of arrival (ToA) of the first repetition of the SL-PRS resource is below a ToA confidence threshold, a confidence in an angle-of-arrival (Ao A) of the first repetition of the SL-PRS resource is below an AoA confidence threshold, or any combination thereof. [0243] Clause 90. The non-transitory computer-readable medium of clause 87, wherein the computer-executable instructions that, when executed by the UE, cause the UE to transmit or refrain from transmitting at least the second repetition comprise computer-executable instructions that, when executed by the UE, cause the UE to: refrain from transmitting remaining repetitions of the plurality of repetitions based on lack of feedback from at least one recipient UE within a time threshold.

[0244] Clause 91. The non-transitory computer-readable medium of any of clauses 87 to 90, further comprising computer-executable instructions that, when executed by the UE, cause the UE to: wait for the feedback from the at least one recipient UE up to a configured time period before the second repetition or sidelink control information (SCI) scheduling the second repetition.

[0245] Clause 92. The non-transitory computer-readable medium of any of clauses 87 to 91, further comprising computer-executable instructions that, when executed by the UE, cause the UE to: wait for the feedback from the at least one recipient UE for a configured time period after the first repetition.

[0246] Clause 93. The non-transitory computer-readable medium of any of clauses 87 to 92, wherein a number of remaining repetitions of the plurality of repetitions is based on: a priority of the SL-PRS resource, an application layer requirement of the UE, a quality of service (QoS) of the SL-PRS resource, a sensing report for the sidelink channel, a channel busy ratio (CBR) of the sidelink channel, a configuration from a network entity, or any combination thereof.

[0247] Clause 94. The non-transitory computer-readable medium of any of clauses 87 to 93, further comprising computer-executable instructions that, when executed by the UE, cause the UE to: receive a configuration of a number of remaining repetitions of the plurality of repetitions from a network entity.

[0248] Clause 95. The non-transitory computer-readable medium of any of clauses 87 to 94, wherein: a set of Y repetitions of the plurality of repetitions is reserved for the UE to transmit the SL-PRS resource to the at least one recipient UE, a set of Z repetitions of the plurality of repetitions is reserved for the at least one recipient UE to transmit a response SL-PRS resource to the UE, and the set of Z repetitions is less than or equal to the plurality of repetitions minus the set of Y repetitions.

[0249] Clause 96. The non-transitory computer-readable medium of any of clauses 87 to 95, wherein: a set of Y repetitions of the plurality of repetitions is reserved for the UE to transmit the SL-PRS resource to the at least one recipient UE, the SL-PRS resource is transmitted in a set of K repetitions of the set of Y repetitions, a set of Z repetitions of the plurality of repetitions is reserved for the at least one recipient UE to transmit a response SL-PRS resource to the UE, and the set of Z repetitions is less than or equal to the plurality of repetitions minus the set of K repetitions.

[0250] Those of skill in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0251] Further, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0252] The various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an ASIC, a field-programable gate array (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 conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. [0253] The methods, sequences and/or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in random access memory (RAM), flash memory, read-only memory (ROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An example storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal (e.g., UE). In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

[0254] In one or more example aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. [0255] While the foregoing disclosure shows illustrative aspects of the disclosure, it should be noted that various changes and modifications could be made herein without departing from the scope of the disclosure as defined by the appended claims. The functions, steps and/or actions of the method claims in accordance with the aspects of the disclosure described herein need not be performed in any particular order. Furthermore, although elements of the disclosure may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.