Coordinated reservation of sidelink resource pool for positioning

Abstract

Techniques for wireless communications are disclosed. In one aspect, a first user equipment (UE) may determine that an RPP from predefined multiple resource pools for positioning (RPP) should be reserved and may transmit a reservation message to at least one other UE indicating reservation of the RPP from the predefined multiple RPP. The RPP may be reserved for use by the first UE or, if the first UE is a relay UE, for use by a remote UE served by the relay UE. The reservation message may be broadcast, groupcast, multicast, etc. In response to receiving the reservation message indicating reservation of the RPP from the predefined multiple RPP, the at least one other UE may modify an intended transmission to reduce interference during the reserved RPP.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims the benefit of Greek Application No. 20210100148, entitled "COORDINATED RESERVATION OF SIDELINK RESOURCE POOLS FOR POSITIONING," filed March 11, 2021, which is assigned to the assignee of the present application and is expressly incorporated herein by reference in its entirety.

[0002] Aspects of the present disclosure relate generally to wireless communications. [Background technology]

[0003] Wireless communication systems have evolved through various generations, including first-generation analog wireless telephone service (1G), second-generation (2G) digital wireless telephone service (including interim 2.5G and 2.75G networks), third-generation (3G) high-speed data, Internet-enabled wireless service, and fourth-generation (4G) service (e.g., Long Term Evolution (LTE) or WiMax). Currently, there are many different types of wireless communication systems in use, including cellular systems and personal communications services (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), Global System for Mobile Communications (GSM), etc.

[0004] The fifth-generation (5G) wireless standard, known as New Radio (NR), promises higher data rates, more connections, and better coverage, among other improvements. According to the Next Generation Mobile Network Alliance, the 5G standard is designed to provide data rates of tens of megabits per second to each of tens of thousands of users, delivering 1 gigabit per second to dozens of workers on an office floor. To support large-scale sensor deployments, hundreds of thousands of simultaneous connections should be supported. Therefore, the spectral efficiency of 5G mobile communications should be significantly enhanced compared to the current 4G standard. Furthermore, signaling efficiency should be enhanced and latency significantly reduced compared to current standards.

[0005] In particular, vehicle-to-everything (V2X) communication technologies are being implemented to leverage 5G's increased data rates and reduced latency to support autonomous driving applications, such as wireless communications between vehicles, between vehicles and roadside infrastructure, and between vehicles and pedestrians. Summary of the Invention [Means for solving the problem]

[0006] Techniques for coordinated reservation of sidelink (SL) resource pools for positioning (RPP) are disclosed. In one aspect, a first user equipment (UE) may determine that an RPP from a predetermined plurality of RPPs should be reserved and may transmit a reservation message to at least one other UE indicating the reservation of the RPP from the predetermined plurality of RPPs. The RPP may be reserved for use by the first UE or, if the first UE is a relay UE, for use by a remote UE served by the relay UE. The reservation message may be broadcast, groupcast, multicast, etc. In response to receiving the reservation message indicating the reservation of the RPP from the predetermined plurality of RPPs, the at least one other UE may modify its intended transmission to reduce interference among the reserved RPPs.

[0007] The following presents a simplified summary related to one or more aspects disclosed herein. As such, the following summary is not intended to be an extensive overview related to all contemplated aspects, nor is it intended to identify key or critical elements related to all contemplated aspects or to delineate the scope related to any particular aspect. As such, the following summary has the sole purpose of presenting some concepts related to one or more aspects related to the mechanisms disclosed herein in a simplified form prior to the detailed description presented below.

[0008] In one aspect, a method of wireless communication performed by a UE includes determining that an RPP from a predetermined plurality of RPPs is to be reserved and transmitting a reservation message to at least one other UE indicating the reservation of the RPP from the predetermined plurality of RPPs.

[0009] In one aspect, a method of wireless communication performed by a UE includes receiving a reservation message indicating a reservation of an RPP from a predetermined plurality of RPPs for use by a second UE, and modifying an intended transmission to reduce interference with the second UE during the reserved RPP.

[0010] In one aspect, a UE includes a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, wherein the at least one processor is configured to determine that an RPP from a predetermined plurality of RPPs should be reserved and cause the at least one transceiver to transmit a reservation message to at least one other UE indicating the reservation of the RPP from the predetermined plurality of RPPs.

[0011] In one aspect, the UE includes a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, wherein the at least one processor is configured to receive a reservation message indicating a reservation of an RPP from a predetermined plurality of RPPs for use by a second UE, and to modify an intended transmission during the reserved RPP to reduce interference with the second UE.

[0012] Other objects and advantages associated with the embodiments disclosed herein will become apparent to those skilled in the art based on the accompanying drawings and detailed description.

[0013] The accompanying drawings are presented to aid in the explanation of various aspects of the present disclosure and are provided solely for the purpose of illustrating the aspects and not for the purpose of limiting the aspects. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 illustrates an exemplary wireless communication system according to aspects of the present disclosure. [Figure 2A] FIG. 1 illustrates an exemplary wireless network structure according to aspects of the present disclosure. [Figure 2B] FIG. 1 illustrates an exemplary wireless network structure according to aspects of the present disclosure. [Figure 3] FIG. 1 illustrates an example of a wireless communication system supporting unicast sidelink establishment according to an aspect of the present disclosure. [Figure 4] FIG. 1 illustrates time and frequency resources used for sidelink communication. [Figure 5A] 1 is a simplified block diagram of several sample aspects of components that may be employed in a user equipment (UE) and configured to support communication as taught herein; [Figure 5B] 1 is a simplified block diagram of several sample aspects of components that may be employed in a base station and configured to support communication as taught herein; [Figure 5C] 1 is a simplified block diagram of several sample aspects of components that may be employed in a network entity and configured to support communications as taught herein; [Figure 6A] 1 illustrates two methods for single-cell UE positioning that may be implemented when a cell includes multiple UEs engaged in SL communications. [Figure 6B] 1 illustrates two methods for single-cell UE positioning that may be implemented when a cell includes multiple UEs engaged in SL communications. [Figure 7] FIG. 1 illustrates a conventional sidelink positioning scenario involving a relay UE serving multiple remote UEs without the involvement of a base station. [Figure 8] 1 illustrates some of the technical drawbacks suffered by conventional methods. [Figure 9] FIG. 1 illustrates an exemplary method of wireless communication according to an aspect of the present disclosure. [Figure 10] FIG. 1 illustrates an exemplary method of wireless communication according to an aspect of the present disclosure. [Figure 11] FIG. 1 illustrates an exemplary method of wireless communication according to an aspect of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] Aspects of the present disclosure are provided in the following description and related drawings, directed to various examples provided for illustrative purposes. Alternative aspects may be devised without departing from the scope of the present disclosure. Additionally, well-known elements of the present disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of the present disclosure.

[0016] 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 present disclosure" does not require that all aspects of the present disclosure include the discussed feature, advantage or mode of operation.

[0017] Those skilled 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 following description 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.

[0018] 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 the various actions described herein may be performed by specific circuitry (e.g., an application-specific integrated circuit (ASIC)), by program instructions executed by one or more processors, or a combination of both. Additionally, the sequences of actions described herein may be considered to be embodied entirely in any form of non-transitory computer-readable storage medium storing a corresponding set of computer instructions that, when executed, cause or instruct the associated processor(s) of the device to perform the functionality described herein. Accordingly, various aspects of the present disclosure may be embodied in a number of different forms, all of which are contemplated to be within the scope of the claimed subject matter. Additionally, for each aspect described herein, the corresponding form of any such aspect may be described herein, for example, as “logic configured to” perform the described actions.

[0019] 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 to or otherwise limited to any particular radio access technology (RAT) unless otherwise specified. In general, a UE may be any wireless communication device (e.g., a vehicle-mounted computer, a vehicle navigation device, a mobile phone, a router, a tablet computer, a laptop computer, a tracking device, a wearable (e.g., a smart watch, smart glasses, an augmented reality (AR) / virtual reality (VR) headset, etc.), a vehicle (e.g., an automobile, a motorcycle, a bicycle, etc.), an Internet of Things (IoT) device, etc.) used by a user to communicate over a wireless communication network. A UE may be mobile or may be stationary (e.g., at some times) and may communicate with a radio access network (RAN). As used herein, the term "UE" may be referred to interchangeably as a "mobile device," "access terminal" or "AT," "client device," "wireless device," "subscriber device," "subscriber terminal," "subscriber station," "user terminal" or UT, "mobile terminal," "mobile station," or variations thereof.

[0020] 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 head-up display (HUD), an on-board computer, etc. Alternatively, a V-UE may be a portable wireless communication device (e.g., a cell phone, a tablet computer, etc.) carried by the driver of the vehicle or a passenger in the vehicle. The term "V-UE" may refer to an 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 carried by a pedestrian (i.e., a user not driving or riding in the vehicle). In general, a UE can communicate with a core network via a RAN, through which the UE can be connected to external networks such as the Internet and other UEs. Of course, other mechanisms for connecting to the core network and / or the Internet are also possible for a UE, such as via a wired access network, a wireless local area network (WLAN) network (e.g., based on IEEE 802.11, etc.), etc.

[0021] A base station may operate according to one of several RATs with which it communicates with the UE, depending on the network in which the UE is deployed, and may alternatively be referred to as an access point (AP), network node, Node B, evolved Node B (eNB), next-generation eNB (ng-eNB), New Radio (NR) Node B (also referred to as gNB or gNode B), etc. Base stations may be used primarily to support wireless access by UEs, including supporting data, voice, and / or signaling connections for supported UEs. In some systems, base stations may provide purely edge node signaling functionality, while in other systems, base stations may provide additional control and / or network management functions. A communication link through which a UE 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 a base station can send signals to a UE is called a downlink (DL) channel or a 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 traffic channel or a DL / forward traffic channel.

[0022] The term "base station" can refer to a single physical transmit / receive point (TRP) or multiple physical TRPs, which may or may not be collocated. For example, when the term "base station" refers to a single physical TRP, the physical TRP may be an antenna of the base station corresponding to the base station's cell (or several cell sectors). When the term "base station" refers to multiple collocated physical TRPs, the physical TRPs may be an array of antennas of the base station (e.g., as in a multiple-input multiple-output (MIMO) system or when the base station employs beamforming). When the term "base station" refers to multiple non-collocated 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, a non-collocated physical TRP may be a serving base station that receives measurement reports from the UE and neighboring base stations whose reference RF signals the UE is measuring. A TRP is a point from which a base station transmits and receives wireless signals, and therefore, as used herein, references to transmission from or reception at a base station should be understood as references to the particular TRP of the base station.

[0023] In some implementations that support UE positioning, a base station may not support wireless access by the UE (e.g., may not support a data connection, a voice connection, and / or a signaling connection for the UE), but instead may transmit reference RF signals to the UE to be measured by the UE and / or may receive and measure signals transmitted by the UE. Such a base station may be referred to as a positioning beacon (e.g., when transmitting RF signals to the UE) and / or a location measurement unit (e.g., when receiving and measuring RF signals from the UE).

[0024] An "RF signal" comprises electromagnetic waves of a given frequency that transport information through 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, due to the propagation characteristics of RF signals through a multipath channel, the receiver may receive multiple "RF signals" corresponding to each transmitted RF signal. The same RF signal transmitted over different paths between a transmitter and a 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" when it is clear from the context that the term "signal" refers to a wireless signal or an RF signal.

[0025] 1 illustrates an exemplary wireless communication system 100 according to an aspect of the present disclosure. The wireless communication system 100 (sometimes referred to as a wireless wide area network (WWAN)) may include various base stations 102 (labeled “BS”) and various UEs 104. The base stations 102 may include macrocell base stations (high-power cellular base stations) and / or small cell base stations (low-power cellular base stations). In one aspect, the macrocell base stations 102 may include eNBs and / or ng-eNBs, where the wireless communication system 100 corresponds to an LTE network, or gNBs, where the wireless communication system 100 corresponds to an NR network, or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, etc.

[0026] The base stations 102 may collectively form a RAN and may interface with a core network 174 (e.g., Evolved Packet Core (EPC) or 5G Core (5GC)) through backhaul links 122 and to one or more location servers 172 (e.g., a Location Management Function (LMF) or a Secure User Plane Localization (SUPL) Location Platform (SLP)) through the core network 174. The location servers 172 may be part of the core network 174 or may be external to the core network 174. In addition to other functions, the base stations 102 may perform functions related to one or more of the following: forwarding user data, radio channel encryption and decryption, 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 tracing, RAN Information Management (RIM), paging, positioning, and distribution of alert messages. The base stations 102 may communicate with each other directly or indirectly (e.g., through EPC / 5GC) via backhaul links 134, which may be wired or wireless.

[0027] 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 the base stations 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 resources referred to as a carrier frequency, component carrier, carrier, band, etc.) and may be associated with an identifier (e.g., physical cell identifier (PCI), enhanced cell identifier (ECI), virtual cell identifier (VCI), cell global identifier (CGI), etc.) to distinguish between cells operating over the same or different carrier frequencies. In some cases, different cells may be configured according to different protocol types (e.g., machine type communication (MTC), narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB), or others) that may provide access to different types of UEs. Because a cell is supported by a particular base station, the term "cell" can refer to a logical communication entity and one or both base stations that support it, depending on the context. In some cases, the term "cell" can also refer to the geographic coverage area (e.g., sector) of a base station, so long as a carrier frequency can be detected and used for communication within some portion of the geographic coverage area 110.

[0028] While adjacent to macrocell base stations 102, the geographic coverage areas 110 may partially overlap (e.g., within handover regions), and some of the geographic coverage areas 110 may be significantly overlapped by larger geographic coverage areas 110. For example, a small cell base station 102' (labeled "SC" instead of "small cell") may have a geographic coverage area 110' that significantly overlaps with the geographic coverage area 110 of one or more macrocell base stations 102. A network including both small cell base stations and macrocell base stations may be referred to as a heterogeneous network. A heterogeneous network may also include Home eNBs (HeNBs) that may serve restricted groups called closed subscriber groups (CSGs).

[0029] The communication link 120 between the base station 102 and the UE 104 may include uplink (also called reverse link) transmissions from the UE 104 to the base station 102, and / or downlink (DL) (also called forward link) transmissions from the base station 102 to the UE 104. The communication link 120 may use MIMO antenna techniques, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link 120 may be over one or more carrier frequencies. The allocation of carriers may be asymmetric for the downlink and uplink (e.g., more or fewer carriers may be allocated for the downlink than for the uplink).

[0030] The wireless communication system 100 may further include a wireless local area network (WLAN) access point (AP) 150 communicating with a WLAN station (STA) 152 via a communication link 154 in an unlicensed frequency spectrum (e.g., 5 GHz). When communicating in the unlicensed frequency spectrum, the WLAN STA 152 and / or the WLAN AP 150 may perform a clear channel assessment (CCA) or listen-before-talk (LBT) procedure before communicating to determine whether a channel is available.

[0031] The small cell base station 102' may operate in a licensed and / or unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell base station 102' may employ LTE or NR technology and may use the same 5 GHz unlicensed frequency spectrum used by the WLAN AP 150. A small cell base station 102' employing LTE / 5G in an unlicensed frequency spectrum may extend coverage to and / or increase the capacity of an access network. NR in an 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 MultiFire.

[0032] The wireless communication system 100 may further include an mmW base station 180 in communication with the UE 182 and capable of operating within mmW and / or quasi-mmW frequencies. Extremely high frequency (EHF) is the RF portion of the electromagnetic spectrum. EHF ranges from 30 GHz to 300 GHz and has wavelengths between 1 and 10 millimeters. Radio waves in this band are sometimes referred to as millimeter waves. Sub-mmW may extend down to frequencies of 3 GHz, with wavelengths of 100 millimeters. The very high frequency (SHF) band extends between 3 GHz and 30 GHz, also known as centimeter waves. Communications using the mmW / quasi-mmW radio frequency bands have high path loss and relatively short distances. The mmW base station 180 and the UE 182 may utilize beamforming (transmit and / or receive) over the mmW communication link 184 to compensate for the significant path loss and short distances. It will be appreciated that in alternative configurations, one or more base stations 102 may also transmit using mmW or quasi-mmW and beamforming. Therefore, it will be appreciated that the above illustrations are merely exemplary and should not be construed as limiting the various aspects disclosed herein.

[0033] Transmit beamforming is a technique for focusing an RF signal in a particular direction. Traditionally, when a network node (e.g., a base station) broadcasts an RF signal, it broadcasts the signal in all directions (omnidirectionally). 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 particular direction, thereby resulting in a faster and more powerful RF signal (in terms of data rate) to the receiving device. To change the directionality of the RF signal when transmitting, the network node can control the phase and relative amplitude of the RF signal at each of one or more transmitters broadcasting the RF signal. For example, the network node may use an array of antennas (called a “phased array” or “antenna array”) that creates a beam of RF waves that can be “steered” to points in different directions without actually moving the antennas. Specifically, RF currents from the transmitter are fed to individual antennas with the appropriate phase relationship so that the radio waves from the separate antennas add together to enhance radiation in desired directions while suppressing or eliminating radiation in undesired directions.

[0034] A transmit beam may be quasi-colocated, meaning that the transmit beam appears to a receiver (e.g., a UE) to have the same parameters regardless of whether the network node's own transmit antennas are physically colocated. In NR, there are four types of quasi-colocation (QCL) relationships. In particular, a QCL relationship of a given type means that some parameters for 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, mean delay, and delay spread of the 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 the 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 spatial reception parameters of a second reference RF signal transmitted on the same channel.

[0035] In receive beamforming, a receiver uses receive beams 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 antenna array in a particular direction to amplify (e.g., increase the gain level of) RF signals received from that direction. Thus, when a receiver is said to beamform in a direction, it means that the beam gain in that direction is greater than the beam gains along other directions, or that the beam gain in that direction is greatest compared to the beam gains 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 RF signals received from that direction.

[0036] The transmit and receive beams may be spatially related. Spatial relationship means that parameters for a second beam (e.g., a transmit beam or a receive beam) for a second reference signal may 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., a synchronization signal block (SSB)) from a base station. The UE can then form a transmit beam for sending an uplink reference signal (e.g., a sounding reference signal (SRS)) to that base station based on the parameters of the receive beam.

[0037] Note that a "downlink" beam may be either a transmit beam or a receive beam, depending on the entity that forms it. For example, if a base station forms a downlink beam to transmit a reference signal to a UE, the downlink beam is a transmit beam. However, if the UE forms a downlink beam, the downlink beam is a receive beam for receiving a downlink reference signal. Similarly, an "uplink" beam may be either a transmit beam or a receive beam, depending on the entity that forms it. For example, if a base station forms an uplink beam, the uplink beam is an uplink receive beam, and if the UE forms an uplink beam, the uplink beam is an uplink transmit beam.

[0038] In 5G, the frequency spectrum in which wireless nodes (e.g., base stations 102 / 180, UEs 104 / 182) operate is divided into multiple frequency ranges: FR1 (450 MHz to 6000 MHz), FR2 (24250 MHz to 52600 MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). The mmW frequency band generally includes the FR2, FR3, and FR4 frequency ranges. Thus, the terms “mmW” and “FR2” or “FR3” or “FR4” may generally be used interchangeably.

[0039] 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 the UE 104 / 182 and the cell on which the UE 104 / 182 either performs an initial radio resource control (RRC) connection establishment procedure or initiates an RRC connection re-establishment procedure. The primary carrier carries all common control channels and UE-specific control channels and may be a carrier among licensed frequencies (although this is not always the case). The secondary carrier is a carrier operating on a second frequency (e.g., FR2) that may be configured once an RRC connection is established between the UE 104 and the anchor carrier and may be used to provide additional radio resources. In some cases, the secondary carrier may be a carrier among unlicensed frequencies. Because both the primary uplink carrier and the primary downlink carrier are typically UE-specific, the secondary carrier may contain only the necessary signaling information and signals; e.g., UE-specific signaling information and signals may not be present in the secondary carrier. This means that different UEs 104 / 182 in a cell may have different downlink primary carriers. The same applies for the uplink primary carrier. The network may 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 PCell or SCell) corresponds to a carrier frequency / component carrier over which several base stations are communicating, terms such as "cell," "serving cell," "component carrier," and "carrier frequency" may be used interchangeably.

[0040] For example, still referring to FIG. 1 , one of the frequencies utilized by the macrocell base station 102 may be an anchor carrier (i.e., “PCell”), and other frequencies utilized by the macrocell base station 102 and / or the mmW base station 180 may be secondary carriers (“SCells”). Simultaneous transmission and / or reception of multiple carriers allows the UE 104 / 182 to significantly increase its data transmission and / or data reception rates. For example, two aggregated 20 MHz carriers in a multi-carrier system would theoretically lead to a two-fold increase in data rate (i.e., 40 MHz) compared to that achieved with a single 20 MHz carrier.

[0041] In the example of FIG. 1 , one or more Earth-orbiting satellite positioning system (SPS) space vehicles (SVs) 112 (e.g., satellites) may be used as independent sources of location information for any of the illustrated UEs (shown in FIG. 1 as a single UE 104 for simplicity). The UE 104 may include one or more dedicated SPS receivers specifically designed to receive SPS signals 124 to derive geolocation information from the SVs 112. An SPS 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 signals received from the transmitters (e.g., SPS signals 124). Such transmitters typically transmit signals marked with a repeating pseudorandom noise (PN) code of a set number of chips. While typically located within the SVs 112, transmitters may sometimes be located on ground-based control stations, base stations 102, and / or other UEs 104.

[0042] Use of SPS signals 124 may 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, SBAS may include augmentation systems that provide integrity information, differential corrections, and the like, such as the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay Service (EGNOS), the Multifunction Satellite Augmentation System (MSAS), the Global Positioning System (GPS)-Aided Geo-Augmented Navigation, or the GPS and Geo-Augmented Navigation System (GAGAN). Thus, as used herein, SPS may include any combination of one or more global and / or regional navigation satellite systems and / or augmentation systems, and SPS signals 124 may include SPS, SPS-like signals, and / or other signals associated with such one or more SPSs.

[0043] In particular, Vehicle-to-Everything (V2X) communication technology is being implemented to leverage NR's increased data rates and reduced latency to support Intelligent Transport Systems (ITS) applications, such as wireless communications between vehicles (Vehicle-to-Vehicle (V2V)), between vehicles and 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 vehicular communications enable safety, mobility, and environmental improvements that current technologies cannot provide. When fully implemented, this technology is expected to reduce unimpaired vehicle collisions by 80%.

[0044] Still referring to FIG. 1 , the wireless communication system 100 may include multiple V-UEs 160, which may communicate with the base station 102 via communication link 120 (e.g., using the Uu interface). The V-UEs 160 may also communicate directly with each other via wireless sidelink 162, with roadside access points 164 (also referred to as “roadside units”) via wireless sidelink 166, or with the UE 104 via wireless sidelink 168. Wireless sidelink (or simply “sidelink”) is an adaptation of the core cellular (e.g., LTE, NR) standard that enables direct communication between two or more UEs without the communication having to go through a base station. Sidelink communication may be unicast or multicast and may be used for D2D medium sharing, V2V communication, V2X communication (e.g., cellular V2X (cV2X) communication, enhanced V2X (eV2X) communication, etc.), emergency response applications, etc. One or more of a group of V-UEs 160 utilizing sidelink communications may be within the geographic coverage area 110 of the base station 102. Other V-UEs 160 in such a group may be outside the geographic coverage area 110 of the base station 102 or may not otherwise be able to receive transmissions from the base station 102. In some cases, a group 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, the base station 102 facilitates scheduling of resources for sidelink communications. In other cases, sidelink communications are performed between V-UEs 160 without the involvement of the base station 102.

[0045] In one aspect, the sidelinks 162, 166, 168 may operate over a target wireless communication medium, which may be shared with other vehicular and / or infrastructure access points, as well as other wireless communications between other RATs. The “medium” may consist of one or more time, frequency, and / or spatial communication resources (e.g., encompassing one or more channels across one or more carriers) associated with wireless communications between one or more transmitter / receiver pairs.

[0046] In one aspect, the sidelinks 162, 166, 168 may be cV2X links. The 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 communication. In the United States and Europe, cV2X is expected to operate within licensed ITS bands in the sub-6 GHz range. Other countries may allocate other bands. Thus, as a specific example, the target medium utilized by the sidelinks 162, 166, 168 may correspond to at least a portion of the sub-6 GHz licensed ITS frequency band. However, the present disclosure is not limited to this frequency band or cellular technology.

[0047] In one aspect, the sidelinks 162, 166, 168 may be dedicated short-range communications (DSRC) links. DSRC is a one-way or two-way, short- to medium-range wireless communication protocol using the wireless access for vehicular environments (WAVE) protocol, also known as IEEE 802.11p, for V2V, V2I, and V2P communications. IEEE 802.11p is an approved amendment to the IEEE 802.11 standard and operates in the licensed ITS band at 5.9 GHz (5.85-5.925 GHz) in the United States. In Europe, IEEE 802.11p 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 over the Safety Channel, a 10 MHz channel typically dedicated to safety purposes in the United States. The remainder of the DSRC band (75 MHz total bandwidth) is dedicated to other driver-facing services, such as road enforcement, toll collection, and automated parking. Thus, as a specific example, the target medium utilized by sidelinks 162, 166, 168 may correspond to at least a portion of the 5.9 GHz licensed ITS frequency band.

[0048] Alternatively, the medium of interest may correspond to at least a portion of an unlicensed frequency band shared among various RATs. While different licensed frequency bands have been reserved for some communication systems (e.g., by government agencies such as the Federal Communications Commission (FCC) in the United States), these systems, particularly those employing small cell access points, have recently extended operation to unlicensed frequency bands such as the Unlicensed National Information Infrastructure (U-NII) bands used by Wireless Local Area Network (WLAN) technologies, most notably the IEEE 802.11x WLAN technology commonly referred to as "Wi-Fi." Exemplary systems of this type include various variants of CDMA systems, TDMA systems, FDMA systems, Orthogonal FDMA (OFDMA) systems, Single-Carrier FDMA (SC-FDMA) systems, etc.

[0049] Communication between V-UEs 160 is referred to as V2V communication, communication between V-UEs 160 and one or more roadside access points 164 is referred to as V2I communication, and communication between V-UEs 160 and one or more UEs 104 (where UEs 104 are P-UEs) is referred to as V2P communication. V2V communication between V-UEs 160 may include, for example, information about the position, speed, acceleration, heading, and other vehicle data of V-UEs 160. V2I information received at V-UEs 160 from one or more roadside access points 164 may include, for example, road regulations, parking automation information, etc. V2P communication between V-UEs 160 and UEs 104 may include, for example, information about the position, speed, acceleration, and heading of V-UEs 160, as well as the position, speed (e.g., if UE 104 is carried by a user on a bicycle), and heading of UEs 104.

[0050] Note that while FIG. 1 illustrates only two of the UEs as V-UEs (V-UE 160), any of the illustrated UEs (e.g., UEs 104, 152, 182, 190) may be V-UEs. Additionally, while only V-UE 160 and a single UE 104 are illustrated as connected via a sidelink, any of the UEs illustrated in FIG. 1, whether V-UEs, P-UEs, etc., may be capable of sidelink communication. Furthermore, although only UE 182 is described as being capable of beamforming, any of the illustrated UEs, including V-UE 160, may be capable of beamforming. If V-UE 160 is capable of beamforming, V-UE 160 may beamform toward each other (i.e., toward other V-UEs 160), toward roadside access point 164, toward other UEs (e.g., UEs 104, 152, 182, 190), etc. Thus, in some cases, the V-UE 160 may utilize beamforming on the sidelinks 162, 166, and 168.

[0051] The wireless communication system 100 may further include one or more UEs, such as a UE 190, that indirectly connect 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, the 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 the UE 190 may indirectly obtain cellular connectivity) and a D2D P2P link 194 with a WLAN STA 152 connected to a WLAN AP 150 (through which the UE 190 may indirectly obtain WLAN-based Internet connectivity). In one example, the D2D P2P links 192 and 194 may be supported using any well-known D2D RAT, such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth®, etc. As another example, the D2D P2P links 192 and 194 may be sidelinks such as those described above with respect to the sidelinks 162, 166, and 168.

[0052] 2A shows 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 a control plane function (C-plane) 214 (e.g., UE registration, authentication, network access, gateway selection, etc.) and a user plane function (U-plane) 212 (e.g., UE gateway function, access to data network, IP routing, etc.), which operate cooperatively to form a core network. A user plane interface (NG-U) 213 and a control plane interface (NG-C) 215 connect a gNB 222 to the 5GC 210, specifically to the user plane function 212 and the control plane function 214, respectively. In an additional configuration, an ng-eNB 224 may also be connected to the 5GC 210 via the NG-C 215 to the control plane function 214 and the NG-U 213 to the user plane function 212. Additionally, the ng-eNB 224 may communicate directly with the gNB 222 via a backhaul connection 223. In some configurations, the next generation RAN (NG-RAN) 220 may have only one or more gNBs 222, while other configurations include one or more of both ng-eNBs 224 and gNBs 222. Either the gNBs 222 or the ng-eNBs 224 (or both) may communicate with the UEs 204 (e.g., any of the UEs described herein). In one aspect, two or more UEs 204 may communicate with each other via a wireless sidelink 242, which may correspond to the wireless sidelink 162 in FIG. 1.

[0053] Another optional aspect may include a location server 230 that may be in communication with the 5GC 210 to provide location assistance to the UE 204. The location servers 230 may be implemented as multiple separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternatively, each may correspond to a single server. The location server 230 may 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 shown). Furthermore, the location server 230 may be integrated into a component of the core network or alternatively, may be external to the core network.

[0054] 2B shows another exemplary wireless network structure 250. The 5GC 260 (which may correspond to the 5GC 210 in FIG. 2A ) may be viewed functionally as a control plane function provided by an access and mobility management function (AMF) 264 and a user plane function provided by a user plane function (UPF) 262, which operate cooperatively to form a core network (i.e., the 5GC 260). A user plane interface 263 and a control plane interface 265 connect the ng-eNB 224 to the 5GC 260, specifically to the UPF 262 and the AMF 264, respectively. In an additional configuration, the gNB 222 may also be connected to the 5GC 260 via the control plane interface 265 to the AMF 264 and the user plane interface 263 to the UPF 262. Furthermore, the ng-eNB 224 may communicate directly with the gNB 222 via the backhaul connection 223, with or without gNB direct connectivity to the 5GC 260. In some configurations, the NG-RAN 220 may have only one or more gNBs 222, while other configurations include one or more of both the ng-eNB 224 and the gNB 222. The base stations of the NG-RAN 220 communicate with the AMF 264 via an N2 interface and with the UPF 262 via an N3 interface. Either the gNB 222 or the ng-eNB 224 (or both) may communicate with a UE 204 (e.g., any of the UEs described herein). In one aspect, two or more UEs 204 may communicate with each other via a sidelink 242, which may correspond to the sidelink 162 in FIG. 1.

[0055] The AMF 264 functions include registration management, connection management, reachability management, mobility management, lawful intercept, transport for session management (SM) messages between the UE 204 and a session management function (SMF) 266, a transparent proxy service for routing SM messages, access authentication and access authorization, transport for short message service (SMS) messages between the UE 204 and a short message service function (SMSF) (not shown), and a security anchor functionality (SEAF). The AMF 264 also interacts with an authentication server function (AUSF) (not shown) and the UE 204 to receive intermediate keys established as a result of the UE 204 authentication process. In the case of UMTS (Universal Mobile Telecommunications System) subscriber identity module (USIM)-based authentication, the AMF 264 retrieves security material from the AUSF. The AMF 264 functions also include security context management (SCM). The SCM receives keys from the SEAF that the SCM uses to derive access network-specific keys. The functionality of the AMF 264 also includes location service management for regulated services, transport for location service messages between the UE 204 and the LMF 270 acting as the location server 230, transport for location service messages between the NG-RAN 220 and the LMF 270, Evolved Packet System (EPS) bearer identifier allocation for interworking with EPS, and UE 204 mobility event notification. In addition, the AMF 264 also supports functionality for non-3GPP access networks.

[0056] The functions of the UPF 262 include acting as an anchor point for intra- / inter-RAT mobility (when applicable), acting as an outer protocol data unit (PDU) session point for interconnection to a data network (not shown), routing and forwarding packets, 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) processing for the user plane (e.g., uplink / downlink rate enforcement, reflective QoS marking in the downlink), uplink traffic validation (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 one or more "end markers" to the source RAN node. The UPF 262 may also support the transfer of location service messages over the user plane between the UE 204 and a location server such as the SLP 272.

[0057] 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 in the UPF 262 to route traffic to the appropriate destination, control of policy enforcement and part of QoS, and downlink data notification. The interface through which the SMF 266 communicates with the AMF 264 is called the N11 interface.

[0058] Another optional aspect may include an LMF 270, which may be in communication with the 5GC 260 to provide location assistance to the UE 204. The LMF 270 may be implemented as multiple separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternatively, each may correspond to a single server. The LMF 270 may 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 shown). The SLP 272 may support similar functions as the LMF 270, while the LMF 270 may communicate with the AMF 264, the NG-RAN 220, and the UE 204 via the control plane (e.g., using interfaces and protocols intended to convey signaling messages rather than voice or data), and the SLP 272 may communicate with the UE 204 and external clients (not shown in FIG. 2B) via the user plane (e.g., using protocols intended to carry voice and / or data, such as Transmission Control Protocol (TCP) and / or IP).

[0059] 3 illustrates an example of a wireless communication system 300 supporting wireless unicast sidelink establishment according to aspects of the present disclosure. In some examples, the wireless communication system 300 may implement aspects of the wireless communication systems 100, 200, and 250. The wireless communication system 300 may include a first UE 302 and a second UE 304, which may be examples of any of the UEs described herein. As specific examples, the UEs 302 and 304 may correspond to the V-UE 160 in FIG. 1, the UE 190 and UE 104 in FIG. 1 connected via the sidelink 192, or the UE 204 in FIG. 2A and 2B.

[0060] In the example of FIG. 3, the UE 302 may attempt to establish a unicast connection with the UE 304 via a sidelink, which may be a V2X sidelink between the UE 302 and the UE 304. As a specific example, the established sidelink connection may correspond to sidelink 162 and / or 168 in FIG. 1 or sidelink 242 in FIGS. 2A and 2B. The sidelink connection may be established in an omnidirectional frequency range (e.g., FR1) and / or an mmW frequency range (e.g., FR2). In some cases, the UE 302 may be referred to as an initiating UE that initiates the sidelink connection procedure, and the UE 304 may be referred to as a target UE that is targeted for the sidelink connection procedure by the initiating UE.

[0061] To establish a unicast connection, Access Stratum (AS) (a functional layer in the UMTS and LTE protocol stacks, and part of Layer 2, between the RAN and the UE responsible for transporting data over the wireless link and managing radio resources) parameters may be configured and negotiated between the UE 302 and the UE 304. For example, transmit and receive capability matching may be negotiated between the UE 302 and the UE 304. Each UE may have different capabilities (e.g., transmit and receive, 64-quadrature amplitude modulation (QAM), transmit diversity, carrier aggregation (CA), supported communication frequency bands, etc.). In some cases, different services may be supported at higher layers of the corresponding protocol stacks for the UE 302 and the UE 304. Additionally, a security association may be established between the UE 302 and the UE 304 for the unicast connection. Unicast traffic may benefit from security protection (e.g., integrity protection) at the link level. Security requirements may differ for different wireless communication systems. For example, V2X and Uu systems may have different security requirements (e.g., Uu security does not include confidentiality protection). Additionally, IP configurations (e.g., IP version, addresses, etc.) may be negotiated for unicast connections between UE 302 and UE 304.

[0062] In some cases, the UE 304 may create a service announcement (e.g., a service capability message) for transmission over a cellular network (e.g., cV2X) to assist in sidelink connection establishment. Traditionally, the UE 302 may identify and locate candidates for sidelink communication based on a broadcasted basic service message (BSM), which is decrypted by nearby UEs (e.g., the UE 304). The BSM may include location information, security and identification information, and vehicle information (e.g., speed, operation, size, etc.) for the corresponding UE. However, in the case of different wireless communication systems (e.g., D2D or V2X communications), the discovery channel may not be configured to allow the UE 302 to detect the BSM. Therefore, the service announcement (e.g., a discovery signal) transmitted by the UE 304 and other nearby UEs may be a higher layer signal and may be broadcast (e.g., in an NR sidelink broadcast). In some cases, the UE 304 may include one or more parameters for itself, including connection parameters and / or capabilities it possesses, in the service announcement. The UE 302 may then monitor for and receive the broadcasted service announcements to identify possible UEs for the corresponding sidelink connection. In some cases, the UE 302 may identify possible UEs based on the capabilities that each UE indicates in its respective service announcement.

[0063] The service announcement may include information to assist the UE 302 (e.g., or any initiating UE) in identifying the UE sending the service announcement (UE 304 in the example of FIG. 3). For example, the service announcement may include channel information over which the direct communication request may be sent. In some cases, the channel information may be RAT-specific (e.g., specific to LTE or NR) and may include a resource pool within which the UE 302 sends the communication request. Additionally, the service announcement may include a specific destination address (e.g., a Layer 2 destination address) for the UE if the destination address is different from the current address (e.g., the address of the streaming provider or the UE sending the service announcement). The service announcement may also include a network layer or transport layer for the UE 302 to send the communication request. For example, the network layer (also referred to as "Layer 3" or "L3") or transport layer (also referred to as "Layer 4" or "L4") may indicate a port number of the application for the UE sending the service announcement. In some cases, IP addressing may not be required if the signaling (e.g., PC5 signaling) directly carries a protocol (e.g., Real-time Transport Protocol (RTP)) or provides a locally generated random protocol. Additionally, the service announcement may include the type of protocol for certificate establishment and QoS-related parameters.

[0064] After identifying a possible sidelink connection target (UE 304 in the example of FIG. 3 ), the initiating UE (UE 302 in the example of FIG. 3 ) may send a connection request 315 to the identified target UE 304. In some cases, the connection request 315 may be a first RRC message (e.g., an "RRCDirectConnectionSetupRequest" message) sent by the UE 302 to request a unicast connection with the UE 304. For example, the unicast connection may utilize a PC5 interface for the sidelink, and the connection request 315 may be an RRC Connection Setup Request message. Additionally, the UE 302 may use a sidelink signaling radio bearer 305 to transport the connection request 315.

[0065] After receiving the connection request 315, the UE 304 may determine whether to accept or reject the connection request 315. The UE 304 may base this decision on transmit / receive capabilities, the ability to accommodate a unicast connection over the sidelink, the particular service indicated for the unicast connection, the content to be transmitted over the unicast connection, or a combination thereof. For example, if the UE 302 desires to use a first RAT to transmit or receive data but the UE 304 does not support the first RAT, the UE 304 may reject the connection request 315. Additionally or alternatively, the UE 304 may reject the connection request 315 based on an inability to accommodate a unicast connection over the sidelink due to limited radio resources, scheduling issues, etc. In response, the UE 304 may transmit an indication of whether the request is accepted or rejected in the connection response 320. Similar to the UE 302 and the connection request 315, the UE 304 may use the sidelink signaling radio bearer 310 to transport the connection response 320. Additionally, the connection response 320 may be a second RRC message sent by the UE 304 in response to the connection request 315 (e.g., an "RRCDirectConnectionResponse" message).

[0066] In some cases, the sidelink signaling radio bearers 305 and 310 may be the same sidelink signaling radio bearer or may be separate sidelink signaling radio bearers. Therefore, the radio link control (RLC) layer acknowledged mode (AM) may be used for the sidelink signaling radio bearers 305 and 310. UEs supporting unicast connections may listen on logical channels associated with the sidelink signaling radio bearers. In some cases, the AS layer (i.e., Layer 2) may pass information directly through RRC signaling (e.g., control plane) rather than through the V2X layer (e.g., data plane).

[0067] If the connection response 320 indicates that the UE 304 accepted the connection request 315, the UE 302 may then send a connection establishment 325 message on the sidelink signaling radio bearer 305 to indicate that the unicast connection setup is complete. In some cases, the connection establishment 325 may be a third RRC message (e.g., an "RRCDirectConnectionSetupComplete" message). Each of the connection request 315, connection response 320, and connection establishment 325 may use basic capabilities when in transport from one UE to another to enable each UE to receive and decode the corresponding transmission (e.g., an RRC message).

[0068] Additionally, an identifier may be used for each of the connection request 315, connection response 320, and connection establishment 325. For example, the identifier may indicate which UE 302 / 304 is sending which message and / or which UE 302 / 304 the message is intended for. For physical (PHY) layer channels, RRC signaling and any subsequent data transmissions may use the same identifier (e.g., Layer 2 ID). However, for logical channels, the identifiers may be separate for RRC signaling and for data transmissions. For example, on logical channels, RRC signaling and data transmissions may be treated differently and may have different acknowledgement (ACK) feedback messaging. In some cases, for RRC messaging, a physical layer ACK may be used to ensure that corresponding messages are transmitted and received correctly.

[0069] One or more information elements may be included in the connection request 315 and / or connection response 320 for the UE 302 and / or UE 304, respectively, to enable negotiation of corresponding AS layer parameters for the unicast connection. For example, the UE 302 and / or UE 304 may include Packet Data Convergence Protocol (PDCP) parameters in the corresponding unicast connection setup message to set up a PDCP context for the unicast connection. In some cases, the PDCP context may indicate whether PDCP replication is utilized for the unicast connection. Additionally, the UE 302 and / or UE 304 may include RLC parameters when establishing the unicast connection to set up an RLC context for the unicast connection. For example, the RLC context may indicate whether AM (e.g., reordering timer (t-reordering) is used) or unacknowledged mode (UM) is used for the RLC layer of the unicast communication.

[0070] Additionally, the UE 302 and / or UE 304 may include medium access control (MAC) parameters to configure a MAC context for a unicast connection. In some cases, the MAC context may enable a resource selection algorithm, a hybrid automatic repeat request (HARQ) feedback scheme (e.g., ACK or negative ACK (NACK) feedback), parameters for the HARQ feedback scheme, carrier aggregation, or a combination thereof for the unicast connection. Additionally, the UE 302 and / or UE 304 may include PHY layer parameters when establishing a unicast connection to configure a PHY layer context for the unicast connection. For example, the PHY layer context may indicate a transmission format (unless a transmission profile is included per UE 302 / 304) and a radio resource configuration (e.g., bandwidth portion (BWP), numerology, etc.) for the unicast connection. These information elements may be supported for different frequency range configurations (e.g., FR1 and FR2).

[0071] In some cases, a security context may also be set for the unicast connection (e.g., after the connection establishment 325 message is sent). Before a security association (e.g., a security context) is established between the UE 302 and the UE 304, the sidelink signaling radio bearers 305 and 310 may not be protected. After the security association is established, the sidelink signaling radio bearers 305 and 310 may be protected. Thus, the security context may enable secure data transmission over the unicast connection as well as the sidelink signaling radio bearers 305 and 310. Additionally, IP layer parameters (e.g., link-local IPv4 or IPv6 addresses) may also be negotiated. In some cases, the IP layer parameters may be negotiated by a higher layer control protocol operating after the RRC signaling is established (e.g., the unicast connection is established). As mentioned above, the UE 304 may base its decision whether to accept or reject the connection request 315 for a particular service indicated for the unicast connection and / or the content (e.g., higher layer information) to be transmitted over the unicast connection. The particular service and / or content may also be indicated by a higher layer control protocol operating after RRC signaling is established.

[0072] After the unicast connection is established, the UE 302 and the UE 304 may communicate using the unicast connection over the sidelink 330, where sidelink data 335 is transmitted between the two UEs 302 and 304. The sidelink 330 may correspond to the sidelinks 162 and / or 168 in FIG. 1 and / or the sidelink 242 in FIG. 2A and 2B. In some cases, the sidelink data 335 may include RRC messages transmitted between the two UEs 302 and 304. To maintain this unicast connection over the sidelink 330, the UE 302 and / or the UE 304 may transmit keep-alive messages (e.g., "RRC Direct Link Alive" messages, fourth RRC messages, etc.). In some cases, the keep-alive messages may be triggered periodically or on-demand (e.g., event-triggered). Thus, the triggering and transmission of keep-alive messages may be invoked by the UE 302 or by both the UE 302 and the UE 304. Additionally or alternatively, a MAC Control Element (CE) (e.g., defined over the sidelink 330) may be used to monitor the status of the unicast connection on the sidelink 330 and maintain the connection. When the unicast connection is no longer needed (e.g., when the UE 302 travels far enough away from the UE 304), either the UE 302 and / or the UE 304 may initiate a release procedure to delete the unicast connection over the sidelink 330. Thus, subsequent RRC messages may not be transmitted between the UE 302 and the UE 304 over the unicast connection.

[0073] Figure 4 illustrates time and frequency resources used for sidelink communication. A time-frequency grid 400 is divided into subchannels in the frequency domain and into time slots in the time domain. Each subchannel comprises a number (e.g., 10, 15, 20, 25, 50, 75, or 100) of physical resource blocks (PRBs), and each slot includes a number (e.g., 14) of OFDM symbols. Sidelink communication can be (pre)configured to occupy fewer than 14 symbols in a slot. For automatic gain control (AGC) settling, the first symbol of a slot is repeated on the preceding symbol. The exemplary slot shown in Figure 4 includes a physical sidelink control channel (PSCCH) portion and a physical sidelink shared channel (PSSCH) portion, with the PSCCH followed by a gap symbol. The PSCCH and PSSCH are transmitted in the same slot.

[0074] Sidelink communication occurs within a transmit or receive resource pool. Sidelink communication occupies one slot and one or more subchannels. Some slots are unavailable for sidelink and some slots contain feedback resources. Sidelink communication can be preconfigured (e.g., preloaded on the UE) or configured (e.g., by the base station via RRC).

[0075] 5A, 5B, and 5C illustrate several example components (represented by corresponding blocks) that may be incorporated within a UE 502 (which may correspond to any of the UEs described herein, including V-UE 160 in FIG. 1), a base station 504 (which may correspond to any of the base stations described herein), and a network entity 506 (which may correspond to or embody any of the network functions described herein, including location server 230 and LMF 270) to support file transmission operations as taught herein. It will be appreciated that these components may be implemented in different types of devices in different implementations (e.g., in an ASIC, in a system-on-chip (SoC), etc.). The illustrated components may also be incorporated into other devices in a communication system. For example, other devices in the system may include components similar to the illustrated components to provide similar functionality. Also, a given device may include one or more of the components. For example, a device may include multiple transceiver components that enable the device to operate on multiple carriers and / or communicate via different technologies.

[0076] The UE 502 and base station 504 each include a wireless wide area network (WWAN) transceiver 510 and 550, respectively, that provides means for communicating (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for refraining from transmitting, etc.) over one or more wireless communications networks (not shown), such as an NR network, an LTE network, a GSM network, etc. The WWAN transceivers 510 and 550 may be connected to one or more antennas 516 and 556, 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 communications medium of interest (e.g., some set of time / frequency resources within a particular frequency spectrum). The WWAN transceivers 510 and 550 may be variously configured to transmit and encode signals 518 and 558 (e.g., messages, indications, information, etc.), respectively, and conversely, to receive and decode signals 518 and 558 (e.g., messages, indications, information, pilots, etc.), respectively, in accordance with a designated RAT. In particular, the WWAN transceivers 510 and 550 include one or more transmitters 514 and 554, respectively, for transmitting and encoding signals 518 and 558, respectively, and one or more receivers 512 and 552, respectively, for receiving and decoding signals 518 and 558, respectively.

[0077] The UE 502 and base station 504 also, at least in some cases, include one or more short-range wireless transceivers 520 and 560, respectively. The short-range wireless transceivers 520 and 560 may be connected to one or more antennas 526 and 566, respectively, and may 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 Communications (NFC), etc.) over a target wireless communications medium. The short-range wireless transceivers 520 and 560 may be variously configured to transmit and encode signals 528 and 568 (e.g., messages, indications, information, etc.), respectively, and conversely, to receive and decode signals 528 and 568 (e.g., messages, indications, information, pilots, etc.), respectively, in accordance with a designated RAT. In particular, the short-range wireless transceivers 520 and 560 include one or more transmitters 524 and 564, respectively, for transmitting and encoding signals 528 and 568, respectively, and one or more receivers 522 and 562, respectively, for receiving and decoding signals 528 and 568, respectively. As specific examples, the short-range wireless transceivers 520 and 560 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.

[0078] Transceiver circuitry including at least one transmitter and at least one receiver may in some implementations comprise an integrated device (e.g., embodied as transmitter and receiver circuitry in a single communications device), in some implementations comprise separate transmitter and receiver devices, or in other implementations may be embodied in other ways. In one aspect, a transmitter may include or be coupled to multiple antennas (e.g., antennas 516, 526, 556, 566), such as an antenna array that enables each device to perform transmit “beamforming” as described herein. Similarly, a receiver may include or be coupled to multiple antennas (e.g., antennas 516, 526, 556, 566), such as an antenna array that enables each device to perform receive beamforming as described herein. In one aspect, transmitters and receivers may share multiple identical antennas (e.g., antennas 516, 526, 556, 566), such that each device can only receive or transmit at a given time, but not both at the same time. The wireless communication device of the UE 502 and / or base station 504 (e.g., one or both of the transceivers 510 and 520 and / or 550 and 560) may also include a network listen module (NLM) or the like for performing various measurements.

[0079] The UE 502 and base station 504 also, at least in some cases, include satellite positioning system (SPS) receivers 530 and 570. The SPS receivers 530 and 570 may be connected to one or more antennas 536 and 576, respectively, and may provide a means for receiving and / or measuring SPS signals 538 and 578, respectively, such as Global Positioning System (GPS) signals, Global Navigation Satellite System (GLONASS) signals, Galileo signals, Beidou signals, Navigation Satellite System of India (NAVIC), Quasi-Zenith Satellite System (QZSS), etc. The SPS receivers 530 and 570 may comprise any suitable hardware and / or software for receiving and processing the SPS signals 538 and 578, respectively. The SPS receivers 530 and 570 request information and actions from other systems as appropriate, and perform the calculations necessary to determine the position of the UE 502 and base station 504 using the obtained measurements, via any suitable SPS algorithms.

[0080] The base station 504 and the network entity 506 each include at least one network interface 580 and 590, respectively, that provide means for communicating (e.g., means for transmitting, means for receiving, etc.) with other network entities. For example, the network interfaces 580 and 590 (e.g., one or more network access ports) may be configured to communicate with one or more network entities via a wire-based or wireless backhaul connection. In some aspects, the network interfaces 580 and 590 may be implemented as transceivers configured to support wire-based or wireless signal communication. This communication may involve, for example, sending and receiving messages, parameters, and / or other types of information.

[0081] In one aspect, the WWAN transceiver 510 and / or the short-range wireless transceiver 520 may form a (wireless) communication interface of the UE 502. Similarly, the WWAN transceiver 550, the short-range wireless transceiver 560, and / or the network interface 580 may form a (wireless) communication interface of the base station 504. Similarly, the network interface 590 may form a (wireless) communication interface of the network entity 506.

[0082] The UE 502, base station 504, and network entity 506 also include other components that may be used in conjunction with operations as disclosed herein. The UE 502 includes processor circuitry implementing a processing system 532, e.g., for providing functionality related to wireless positioning and for providing other processing functionality. The base station 504 includes a processing system 584, e.g., for providing functionality related to wireless positioning and for providing other processing functionality. The network entity 506 includes a processing system 594, e.g., for providing functionality related to wireless positioning and for providing other processing functionality. Thus, the processing systems 532, 584, and 594 may provide means for processing, such as means for determining, means for calculating, means for receiving, means for transmitting, means for indicating, etc. In one aspect, the processing systems 532, 584, and 594 may include one or more processors, such as, for example, one or more general-purpose processors, multi-core processors, ASICs, digital signal processors (DSPs), field programmable gate arrays (FPGAs), other programmable logic devices or processing circuitry, or various combinations thereof.

[0083] The UE 502, the base station 504, and the network entity 506 include memory circuitry implementing memory components 540, 586, and 596, respectively (e.g., each including a memory device) for maintaining information (e.g., information indicative of reserved resources, thresholds, parameters, etc.). The memory components 540, 586, and 596 may thus provide means for storing, retrieving, retaining, etc. In some cases, the UE 502, the base station 504, and the network entity 506 may include sidelink managers 542, 588, and 598, respectively. The sidelink managers 542, 588, and 598 may be hardware circuits that are part of or coupled to the processing systems 532, 584, and 594, respectively, that, when executed, cause the UE 502, the base station 504, and the network entity 506 to perform the functionality described herein. In other aspects, the sidelink managers 542, 588, and 598 may be external to the processing systems 532, 584, and 594 (e.g., may be part of a modem processing system, may be integrated with another processing system, etc.). Alternatively, the sidelink managers 542, 588, and 598 may be memory modules stored in the memory components 540, 586, and 596, respectively, that, when executed by the processing systems 532, 584, and 594 (or the modem processing system, another processing system, etc.), cause the UE 502, the base station 504, and the network entity 506 to perform the functionality described herein. FIG. 5A shows possible locations for the sidelink manager 542, which may be part of the WWAN transceiver 510, the memory component 540, the processing system 532, or any combination thereof, or may be a standalone component. FIG. 5B shows possible locations for the sidelink manager 588, which may be part of the WWAN transceiver 550, memory component 586, processing system 584, or any combination thereof, or may be a stand-alone component.FIG. 5C shows possible locations for a sidelink manager 598, which may be part of the network interface 590, memory component 596, processing system 594, or any combination thereof, or may be a stand-alone component.

[0084] The UE 502 may include one or more sensors 544 coupled to the processing system 532 to provide a means for sensing or detecting motion and / or orientation information that is independent of motion data derived from signals received by the WWAN transceiver 510, the short-range wireless transceiver 520, and / or the SPS receiver 530. By way of example, the sensors 544 may include an accelerometer (e.g., a microelectromechanical system (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometric altimeter), and / or any other type of motion detection sensor. Moreover, the sensors 544 may include multiple different types of devices and combine their outputs to provide motion information. For example, the sensors 544 may use a combination of a multi-axis accelerometer and an orientation sensor to provide the ability to calculate a position in a 2D and / or 3D coordinate system.

[0085] Additionally, the UE 502 includes a user interface 546 that provides a means for providing an indication to a user (e.g., an audio and / or visual indication) and / or receiving user input (e.g., upon user actuation of a sensing device such as a keypad, touch screen, microphone, etc.). Although not shown, the base station 504 and the network entity 506 may also include user interfaces.

[0086] Referring more particularly to the processing system 584, on the downlink, IP packets from the network entity 506 may be provided to the processing system 584. The processing system 584 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 processing system 584 may provide RRC layer functionality related to broadcasting of system information (e.g., Master Information Block (MIB), System Information Block (SIB)), 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 related to header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality related to transfer of upper layer PDUs, error correction through automatic repeat request (ARQ), concatenation, segmentation, and reassembly of RLC service data units (SDUs), resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality related to mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization.

[0087] The transmitter 554 and receiver 552 may implement Layer 1 (L1) functionality related to various signal processing functions. Layer 1, which includes the physical (PHY) layer, may include error detection on transport channels, forward error correction (FEC) coding / decoding of transport channels, interleaving, rate matching, mapping onto physical channels, modulation / demodulation of physical channels, and MIMO antenna processing. The transmitter 554 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-ary 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., a pilot) in the time and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain OFDM symbol stream. The OFDM symbol stream is spatially precoded to generate multiple spatial streams. Channel estimates from a channel estimator may be used to determine coding and modulation schemes and for spatial processing. The channel estimates may be derived from a reference signal and / or channel condition feedback transmitted by the UE 502. Each spatial stream may then be provided to one or more different antennas 556. The transmitter 554 may modulate an RF carrier with the respective spatial stream for transmission.

[0088] At the UE 502, the receiver 512 receives signals through its respective antenna 516. The receiver 512 recovers the information modulated onto the RF carriers and provides the information to the processing system 532. The transmitter 514 and receiver 512 perform Layer 1 functionality related to various signal processing functions. The receiver 512 may perform spatial processing on the information to recover any spatial streams destined for the UE 502. Multiple spatial streams may be combined into a single OFDM symbol stream by the receiver 512 if destined for the UE 502. The receiver 512 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, as well as the reference signal, are recovered and demodulated by determining the signal constellation point that was most likely transmitted by the base station 504. These soft decisions may be based on channel estimates calculated by a channel estimator. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted on the physical channel by the base station 504. The data and control signals are then provided to a processing system 532 that performs Layer 3 (L3) and Layer 2 (L2) functionality.

[0089] In the uplink, the processing system 532 performs demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the core network. The processing system 532 is also responsible for error detection.

[0090] Similar to the functionality described with respect to downlink transmissions by the base station 504, the processing system 532 provides RRC layer functionality related to system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality related to header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality related to transfer of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality related to 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 via hybrid automatic repeat request (HARQ), priority handling, and logical channel prioritization.

[0091] Channel estimates derived by the channel estimator from a reference signal or feedback transmitted by the base station 504 may be used by the transmitter 514 to select an appropriate coding and modulation scheme and to facilitate spatial processing. The spatial streams generated by the transmitter 514 may be provided to different antennas 516. The transmitter 514 may modulate an RF carrier with each spatial stream for transmission.

[0092] Uplink transmissions are processed at the base station 504 in a manner similar to that described with respect to the receiver function at the UE 502. The receiver 552 receives the signal through its respective antenna 556. The receiver 552 recovers the information modulated onto the RF carrier and provides the information to the processing system 584.

[0093] In the uplink, the processing system 584 performs demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the UE 502. The IP packets from the processing system 584 may be provided to the core network. The processing system 584 is also responsible for error detection.

[0094] For convenience, the UE 502, the base station 504, and / or the network entity 506 are illustrated in Figures 5A-5C as including various components that may be configured in accordance with various examples described herein. However, it will be appreciated that the illustrated blocks may have different functionality in different designs.

[0095] The various components of the UE 502, the base station 504, and the network entity 506 may communicate with one another via data buses 534, 582, and 592, respectively. In an aspect, the data buses 534, 582, and 592 may form or be part of a communication interface of the UE 502, the base station 504, and the network entity 506, respectively. For example, when various logical entities are embodied within the same device (e.g., gNB and location server functionality incorporated within the same base station 504), the data buses 534, 582, and 592 may provide communication therebetween.

[0096] The components of Figures 5A-5C may be implemented in various ways. In some implementations, the components of Figures 5A-5C 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), where each circuit may use and / or incorporate at least one memory component for storing information or executable code used by the circuit to provide its functionality. For example, some or all of the functionality represented by blocks 510-546 may be performed by the processor and memory components of the UE 502 (e.g., by execution of appropriate code and / or by appropriate configuration of the processor components). Similarly, some or all of the functionality represented by blocks 550-588 may be performed by the processor and memory components of the base station 504 (e.g., by execution of appropriate code and / or by appropriate configuration of the processor components). Additionally, some or all of the functionality represented by blocks 590-598 may be implemented by the processor and memory components of the network entity 506 (e.g., by execution of appropriate code and / or by appropriate configuration of the processor components). For simplicity, various operations, acts, and / or functions are described herein as being performed "by the UE," "by the base station," "by the network entity," etc. However, it will be appreciated that such operations, acts, and / or functions may actually be performed by particular components or combinations of components, such as the UE 502, the base station 504, the network entity 506, the processing systems 532, 584, 594, the transceivers 510, 520, 550, and 560, the memory components 540, 586, and 596, the sidelink managers 542, 588, and 598, etc.

[0097] Figures 6A and 6B show two methods for single-cell UE positioning that may be implemented when a cell includes multiple UEs engaged in SL communications. In Figures 6A and 6B, a UE transmitting an SL-PRS may be referred to as a "TxUE," and a UE receiving an SL-PRS may be referred to as an "RxUE." The methods shown in Figures 6A and 6B have the technical advantage that they do not require any uplink transmission, which can save power.

[0098] In Figure 6A, a relay UE 600 (whose location is known) participates in position estimation of a remote UE 602 without having to perform any UL PRS transmissions to a base station 604 (e.g., a gNB). As shown in Figure 6A, the remote UE 602 receives a DL-PRS from a BS 604 and transmits an SL-PRS to the relay UE 600. Because the SL-PRS transmission from the remote UE 602 does not need to reach the BS 604, but only the nearby relay UE 600, this SL-PRS transmission can be low power.

[0099] In Figure 6B, multiple relay UEs, including relay UE 600 acting as a first relay UE and relay UE 606 acting as a second relay UE, transmit SL-PRS signals (SL-PRS1 and SL-PRS2, respectively) to remote UE 602. In contrast to the method shown in Figure 6A, where remote UE 602 was a TxUE and relay UE 600 was an RxUE, in Figure 6B, the roles are reversed, with relay UE 600 and relay UE 606 being TxUEs and remote UE 602 being an RxUE. In this scenario, too, the SL-PRS signals transmitted by the TxUEs may be low power and no UL communication is required.

[0100] FIG. 7 illustrates a conventional sidelink positioning scenario 700 involving a relay UE 600 serving multiple remote UEs 602 without base station involvement. The relay UE 600 and remote UEs 602 are (pre-)configured with a set of positioning resource pools (RPPs). In this scenario, each remote UE 602 can send a positioning request to the relay UE 600, which may respond to each positioning request by sending a configuration message to the remote UE 602 that assigns an RPP to each remote UE 602 for use by that remote UE. The positioning request may specify a particular RPP that the requesting remote UE 704 wants to use, or it may be a general request for any available RPP, in which case the relay UE 600 selects an RPP from the set of RPPs. The configuration message may assign the requested RPP (if an RPP is requested), or the relay UE 600 may choose another RPP from the set of RPPs.

[0101] Figure 8 illustrates some of the technical drawbacks posed by the conventional method shown in Figure 7. In Figure 8, multiple relay UEs 600 and their corresponding remote UEs 602 are in close proximity to each other, and each relay UE 600 may assign an RPP to one of its remote UEs 602 without considering which neighboring relay UEs 600 have assigned an RPP to their respective remote UEs 602. As a result, two remote UEs 602 may attempt to use the same RPP at the same time, thus interfering with each other. Current standards do not specify a mechanism by which such interference may be avoided in advance. To address these technical drawbacks, a technique for coordinated reservation of SL RPPs is presented.

[0102] FIG. 9 illustrates a method 900 for coordinated reservation of SL RPPs according to an aspect of the present disclosure. In FIG. 9, a first relay UE 600A serves remote UEs 602A and 602B, and a second relay UE 600B serves remote UEs 602C and 602D. The number of relay UEs and the number of remote UEs served by each relay UE may vary; these numbers are exemplary and not limiting. Each UE is configured with a default set of RPPs. The default RPPs may be preloaded on the UE or may be configured by the serving base station, for example, via the RCC.

[0103] In method 900, the UE determines that an RPP from a predetermined plurality of RPPs should be reserved. In the example shown in FIG. 9, the relay UE 600 receives a request from a remote UE 602A for an RPP from a predetermined plurality of RPPs. The remote UE 602A may issue a general request for any available RPP, in which case the relay UE 600 may select one of the RPPs from the predetermined set of RPPs. Alternatively, the remote UE 602A may request a specific RPP, in which case the relay UE 600 may select the specific RPP, or the relay UE 600 may select a different RPP, for example, when the requested RPP is unavailable due to being reserved by another remote UE or for some other reason.

[0104] In response, the relay UE 600A transmits a reservation message to reserve the specified RPP. The reservation message may be transmitted via a broadcast message, a groupcast message, or a multicast message. The reservation message may be transmitted via a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), or a combination thereof. In one aspect, the reservation message is transmitted to the remote UE 602B and the relay UE 600B, and the relay UE 600B relays the message to the remote UE 602C and the remote UE 602D. Alternatively, the reservation message is transmitted to the relay UE 600B, the remote UE 602B, the remote UE 602C, and the remote UE 602D simultaneously. Alternatively, the relay UE 600A may send a set of unicast messages to neighboring UEs.

[0105] The reservation message may include additional information such as, but not limited to, the following: The reservation message may indicate that the Sidelink Positioning Reference Signal (SL-PRS) will be transmitted using the reserved RPP. The reservation message may specify the specific SL-PRS resources within the RPP to be used. The reservation message may identify the remote UEs that will use the reserved RPP. The reservation message may include an RPP identifier. The reservation message may include a zone identifier that specifies one or more geographical zones to which the reservation applies.

[0106] The reservation message may include a priority indication that specifies the relative priority of the positioning operation with respect to other types of operations that may also use the resources of the RPP. For example, if the priority of the positioning operation is higher than the priority of data or reference signal transmissions by neighboring UEs, the neighboring UEs are expected to avoid scheduling; otherwise, the neighboring UEs can still be scheduled.

[0107] A reservation request may include or imply a request that the UEs receiving the reservation request (and that are within the specified zone, if applicable) reduce interference during the reserved RPP, e.g., by rate-matching, muting, puncturing, reducing transmit power, or a combination thereof, during the reserved RPP and, if applicable, within the specified SL-PRS resources. In the example shown in FIG. 9, relay UE 600B, remote UE 602B, remote UE 602C, and remote UE 602D may respond to the reservation request by, e.g., modifying their intended transmissions to reduce interference with remote UE 602B during the reserved RPP.

[0108] In some aspects, the reservation message may include timing information associated with the reservation, such as, but not limited to, the timing information associated with the reservation comprising a start time of the RPP, an end time of the RPP, a time offset of the RPP, a periodicity of the RPP, an indicator that the RPP does not repeat (e.g., this is a one-off request), or combinations thereof.

[0109] 9, the relay UE 600A then sends a configuration message to the remote UE 602A. The configuration message identifies the RPP to be used by the remote UE 602A and may also specify a subset of SL-PRS resources within the RPP to be used by the remote UE 602A. In some aspects, the SL-PRS resources within the reserved RPP may be identified by an index. If a time domain index is used, the time domain index may be relative to the RPP. The SL-PRS resources to be used by the remote UE 602A may include all or a portion of the SL-PRS resources within the reserved RPP.

[0110] In the example shown in FIG. 9, the relay UE 600A sends the reservation message, but alternatively, the remote UE 602A may send the reservation message.

[0111] 10 is a flowchart of an example process 1000 related to coordinated reservation of a sidelink resource pool for positioning. In some implementations, one or more process blocks of FIG. 10 may be performed by a UE (e.g., UE 500, UE 600, UE 602). In some implementations, one or more process blocks of FIG. 10 may be performed by another device or a group of devices that are separate from or include the UE. Additionally or alternatively, one or more process blocks of FIG. 10 may be performed by one or more components of the device 500, such as the processing system 510, the memory 514, the transceiver 504, the SPS receiver 506, the sidelink manager 570, and the user interface 550, any or all of which may be considered means for performing this operation.

[0112] 10 , process 1000 may include determining that an RPP from a plurality of predefined positioning resource pools (RPPs) is to be reserved (block 1010). Means for performing the operations in block 1010 may include the processing system 554 of the UE 502. For example, the UE 502 may determine that an RPP from a plurality of predefined positioning resource pools (RPPs) is to be reserved using the processing system 552, as described above. In some aspects, the predefined plurality of RPPs is preloaded on the UE. In some aspects, the predefined plurality of RPPs is configured by a serving base station. In some aspects, determining that an RPP from the predefined plurality of RPPs is to be reserved comprises selecting an RPP from the predefined plurality of RPPs.

[0113] In some aspects, the operations at block 1010 may be performed by the relay UE in response to receiving a request for an RPP from a predetermined plurality of RPPs from a remote UE served by the relay UE (block 1005). Means for performing the operations at block 1005 may include the WWAN transceiver 510 and the processing system 554 of the UE 502. For example, the UE 502 may receive the request from the remote UE via the receiver 512, as described above. In some aspects, the request identifies a particular RPP from the predetermined plurality of RPPs. In some aspects, the reservation message indicates a reservation of the particular RPP identified in the request. In some aspects, the reservation message indicates a reservation of an RPP different from the particular RPP identified in the request.

[0114] 10, process 1000 may include transmitting a reservation message to at least one other UE indicating reservation of an RPP from the predetermined plurality of RPPs (block 1020). Means for performing the operations in block 1020 may include the WWAN transceiver 510 and the processing system 552 of the UE 502. For example, the UE 502 may transmit the reservation message indicating reservation of an RPP from the predetermined plurality of RPPs via the transmitter 514, as described above.

[0115] In some aspects, the reservation message is transmitted via a broadcast message, a groupcast message, or a multicast message. In some aspects, the reservation message is transmitted via a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), or a combination thereof. In some aspects, the reservation message indicates that a sidelink positioning reference signal (SL-PRS) is transmitted using the reserved RPP. In some aspects, the reservation message identifies a remote UE using the reserved RPP. In some aspects, the reservation message comprises an RPP identifier. In some aspects, the reservation message comprises a zone identifier. In some aspects, the reservation message comprises a priority indication. In some aspects, the reservation message comprises timing information related to the reservation. In some aspects, the timing information related to the reservation comprises a start time of the RPP, an end time of the RPP, a time offset of the RPP, a periodicity of the RPP, an indicator that the RPP does not repeat, or a combination thereof. In some aspects, the reservation message comprises a request that at least one other UE reduce interference during the reserved RPP. In some aspects, reducing interference comprises rate matching, muting, puncturing, reducing transmit power, or a combination thereof.

[0116] 10 , process 1000 may include, for example, when process 1000 is being performed by a relay UE, transmitting an RPP configuration identifying the reserved RPP to a remote UE (block 1030). Means for performing the operations at block 1030 may include the WWAN transceiver 510 and the processing system 552 of the UE 502. For example, the UE 502 may transmit the RPP configuration identifying the reserved RPP via the transmitter 514, as described above. In some aspects, the RPP configuration may identify specific SL-PRS resources within the reserved RPP to be used by the remote UE. In some aspects, the SL-PRS resources within the reserved RPP are identified by an index. In some aspects, the identified SL-PRS resources comprise all or a portion of the SL-PRS resources in the reserved RPP.

[0117] Process 1000 may include additional implementations, such as any single implementation or any combination of implementations described below and / or with respect to one or more other processes described elsewhere herein.

[0118] 10 illustrates example blocks of process 1000, in some implementations, process 1000 may include additional, fewer, different, or differently configured blocks than those illustrated in FIG 10. Additionally or alternatively, two or more of the blocks of process 1000 may be performed in parallel.

[0119] 11 is a flowchart of an example process 1100 related to coordinated reservation of a sidelink resource pool for positioning. In some implementations, one or more process blocks of FIG. 11 may be performed by a UE (e.g., UE 500, UE 600, UE 602). In some implementations, one or more process blocks of FIG. 11 may be performed by another device or a group of devices that are separate from or include the user equipment (UE). Additionally or alternatively, one or more process blocks of FIG. 11 may be performed by one or more components of the device 500, such as the processing system 510, the memory 514, the transceiver 504, the SPS receiver 506, the sidelink manager 570, and the user interface 550, any or all of which may be considered means for performing this operation.

[0120] 11, process 1100 may include receiving a reservation message indicating a reservation of an RPP from a predetermined plurality of RPPs for use by the second UE (block 1110). Means for performing the operations in block 1110 may include the WWAN transceiver 512 and the processing system 552 of the UE 502. For example, the UE 502 may receive the reservation message via the receiver 512 indicating a reservation of an RPP from a predetermined plurality of RPPs for use by the second UE, as described above.

[0121] In some aspects, the pre-defined multiple RPPs are pre-loaded. In some aspects, the pre-defined multiple RPPs are configured by the serving base station. In some aspects, the reservation message is received via a broadcast message, a groupcast message, or a multicast message. In some aspects, the reservation message is received via a PSCCH, a PSSCH, or a combination thereof. In some aspects, the reservation message indicates that a SL-PRS will be transmitted using the reserved RPP. In some aspects, the reservation message identifies a second UE using the reserved RPP. In some aspects, the reservation message comprises an RPP identifier. In some aspects, the reservation message comprises a zone identifier. In some aspects, the reservation message comprises a priority indication. In some aspects, the reservation message comprises timing information associated with the reservation. In some aspects, the timing information associated with the reservation comprises a start time of the RPP, an end time of the RPP, a time offset of the RPP, a periodicity of the RPP, an indicator that the RPP does not repeat, or a combination thereof. In some aspects, the reservation message identifies sidelink positioning reference signal (SL-PRS) resources within the reserved RPP. In some aspects, the SL-PRS resources in the reserved RPP are identified by an index, hi some aspects, the identified SL-PRS resources comprise all or a portion of the SL-PRS resources in the reserved RPP.

[0122] 11, the process 1100 may include modifying an intended transmission to reduce interference with the second UE during the reserved RPP (block 1120). Means for performing the operations in block 1120 may include the WWAN transceiver 512 and the processing system 552 of the UE 502. For example, the processing system 552 of the UE 502 may modify an intended transmission by the transmitter 514 to reduce interference with the second UE during the reserved RPP, as described above. In some aspects, modifying the intended transmission comprises rate matching, muting, puncturing, reducing transmit power, or a combination thereof.

[0123] Process 1100 may include additional implementations, such as any single implementation or any combination of implementations described below and / or with respect to one or more other processes described elsewhere herein.

[0124] 11 illustrates example blocks of process 1100, in some implementations, process 1100 may include additional, fewer, different, or differently configured blocks than those illustrated in FIG 11. Additionally or alternatively, two or more of the blocks of process 1100 may be performed in parallel.

[0125] In the above detailed description, it can be seen that various features are grouped together in the examples. This manner of disclosure should not be understood as an intention that the example clauses have more features than are expressly recited in each clause. Rather, various aspects of the present disclosure may include fewer than all features of each example clause disclosed. Accordingly, the following clauses are hereby considered to be incorporated into this description, and each clause may stand alone as a separate example. Although each dependent clause may refer to a specific combination with one of the other clauses within that clause, the aspects of that dependent clause are not limited to that specific combination. It will be appreciated that other example clauses can also include combinations of aspects of that dependent clause with the subject matter of any other dependent clause or independent clause, or combinations of any features with other dependent clauses and independent clauses. The various aspects disclosed herein expressly include combinations of these combinations unless a particular combination is expressly expressed or can be readily inferred (e.g., contradictory aspects, such as defining an element as both an insulator and a conductor). It is further contemplated that aspects of a clause may be included within any other independent clause, even if the clause is not directly dependent on the independent clause.

[0126] Exemplary aspects are described in the following numbered clauses.

[0127] Clause 1. A method of wireless communications performed by a user equipment (UE), the method comprising: determining that an RPP from a plurality of predefined positioning resource pools (RPPs) should be reserved; and transmitting a reservation message to at least one other UE indicating reservation of the RPP from the plurality of predefined RPPs.

[0128] Clause 2. The method of clause 1, wherein the predetermined plurality of RPPs are preloaded.

[0129] Clause 3. The method of any of clauses 1-2, wherein the predetermined plurality of RPPs are configured by the serving base station.

[0130] Clause 4. The method of any of clauses 1-3, wherein determining that an RPP from a predetermined plurality of RPPs should be reserved comprises selecting an RPP from the predetermined plurality of RPPs.

[0131] Clause 5. The method of any one of clauses 1 to 4, wherein the reservation message is transmitted via a broadcast message, a groupcast message, or a multicast message.

[0132] Clause 6. The method of any of clauses 1 to 5, wherein the reservation message is transmitted via a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), or a combination thereof.

[0133] Clause 7. The method of any of clauses 1 to 6, wherein the reservation message indicates that the sidelink positioning reference signal (SL-PRS) is to be transmitted using the reserved RPP.

[0134] Clause 8. The method of any of clauses 1 to 7, wherein the reservation message identifies a remote UE that uses the reserved RPP.

[0135] Clause 9. The method of any of clauses 1 to 8, wherein the reservation message comprises an RPP identifier.

[0136] Clause 10. The method of any of clauses 1 to 9, wherein the reservation message comprises a zone identifier.

[0137] Clause 11. The method of any of clauses 1 to 10, wherein the reservation message comprises a priority indication.

[0138] Clause 12. The method of any of clauses 1 to 11, wherein the reservation message comprises timing information associated with the reservation.

[0139] Clause 13. The method of clause 12, wherein the timing information associated with the reservation comprises a start time of the RPP, an end time of the RPP, a time offset of the RPP, a periodicity of the RPP, an indicator that the RPP does not repeat, or a combination thereof.

[0140] Clause 14. The method of any of clauses 1 to 13, wherein the reservation message comprises a request that at least one other UE reduce interference during the reserved RPP.

[0141] Clause 15. The method of clause 14, wherein reducing interference comprises rate matching, muting, puncturing, reducing transmit power, or a combination thereof.

[0142] Clause 16. The method of any of clauses 1 to 15, wherein the UE comprises a relay UE associated with the remote UE.

[0143] Clause 17. The method of clause 16, further comprising receiving a request from a remote UE for an RPP from the predetermined plurality of RPPs, wherein determining the RPP from the predetermined plurality of RPPs is based on receiving the request.

[0144] Clause 18. The method of clause 17, wherein the request identifies a particular RPP from a predetermined plurality of RPPs.

[0145] Clause 19. The method of clause 18, wherein the reservation message indicates a reservation for a particular RPP identified in the request.

[0146] Clause 20. The method of any of clauses 18-19, wherein the reservation message indicates a reservation for an RPP different from the particular RPP identified in the request.

[0147] Clause 21. The method of any of clauses 16 to 20, further comprising transmitting an RPP configuration to the remote UE that identifies a reserved RPP to be used by the remote UE.

[0148] Clause 22. The method of clause 21, wherein the RPP configuration identifies sidelink positioning reference signal (SL-PRS) resources within the reserved RPP.

[0149] Clause 23. The method of clause 22, wherein the SL-PRS resource within the reserved RPP is identified by an index.

[0150] Clause 24. The method of any of clauses 22-23, wherein the identified SL-PRS resources comprise all or part of the SL-PRS resources in the reserved RPP.

[0151] Clause 25. A method of wireless communications performed by a user equipment (UE), the method comprising: receiving a reservation message indicating a reservation of an RPP from a predetermined plurality of RPPs for use by a second UE; and modifying an intended transmission during the reserved RPP to reduce interference with the second UE.

[0152] Clause 26. The method of clause 25, wherein modifying the intended transmission comprises rate matching, muting, puncturing, reducing transmit power, or a combination thereof.

[0153] Clause 27. The method of any of clauses 25-26, wherein the predetermined plurality of RPPs is preloaded.

[0154] Clause 28. The method of any of clauses 25-27, wherein the predetermined plurality of RPPs is configured by the serving base station.

[0155] Clause 29. The method of any of clauses 25 to 28, wherein the reservation message is received via a broadcast message, a groupcast message, or a multicast message.

[0156] Clause 30. The method of any of clauses 25 to 29, wherein the reservation message is received via a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), or a combination thereof.

[0157] Clause 31. The method of any of clauses 25 to 30, wherein the reservation message indicates that the sidelink positioning reference signal (SL-PRS) is to be transmitted using the reserved RPP.

[0158] Clause 32. The method of any of clauses 25 to 31, wherein the reservation message identifies a second UE that uses the reserved RPP.

[0159] Clause 33. The method of any of clauses 25 to 32, wherein the reservation message comprises an RPP identifier.

[0160] Clause 34. The method of any of clauses 25 to 33, wherein the reservation message comprises a zone identifier.

[0161] Clause 35. The method of any of clauses 25 to 34, wherein the reservation message comprises a priority indication.

[0162] Clause 36. The method of any of clauses 25 to 35, wherein the reservation message comprises timing information associated with the reservation.

[0163] Clause 37. The method of clause 36, wherein the timing information associated with the reservation comprises a start time of the RPP, an end time of the RPP, a time offset of the RPP, a periodicity of the RPP, an indicator that the RPP does not repeat, or a combination thereof.

[0164] Clause 38. The method of any of clauses 25 to 37, wherein the reservation message identifies sidelink positioning reference signal (SL-PRS) resources within the reserved RPP.

[0165] Clause 39. The method of clause 38, wherein the SL-PRS resource within the reserved RPP is identified by an index.

[0166] Clause 40. The method of any of clauses 38-39, wherein the identified SL-PRS resources comprise all or part of the SL-PRS resources in the reserved RPP.

[0167] Clause 41. 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, wherein the at least one processor is configured to: determine that an RPP from a plurality of predefined positioning resource pools (RPPs) should be reserved; and cause the at least one transceiver to transmit a reservation message to at least one other UE indicating the reservation of the RPP from the plurality of predefined RPPs.

[0168] Clause 42. The UE of clause 41, wherein a predetermined plurality of RPPs are preloaded.

[0169] Clause 43. For a UE according to any one of clauses 41 to 42, the predetermined plurality of RPPs are configured by a serving base station.

[0170] Clause 44. In a UE of any of clauses 41 to 43, to determine that an RPP from a predefined plurality of RPPs should be reserved, the processor is configured to select an RPP from the predefined plurality of RPPs.

[0171] Clause 45. The UE of any one of clauses 41 to 44, wherein the reservation message is transmitted via a broadcast message, a groupcast message, or a multicast message.

[0172] Clause 46. The UE of any of clauses 41 to 45, wherein the reservation message is transmitted via a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), or a combination thereof.

[0173] Clause 47. The UE of any of clauses 41 to 46, wherein the reservation message indicates that a sidelink positioning reference signal (SL-PRS) is to be transmitted using the reserved RPP.

[0174] Clause 48. The UE of any of clauses 41 to 47, wherein the reservation message identifies a remote UE that uses the reserved RPP.

[0175] Clause 49. The UE of any one of clauses 41 to 48, wherein the reservation message comprises an RPP identifier.

[0176] Clause 50. The UE of any one of clauses 41 to 49, wherein the reservation message comprises a zone identifier.

[0177] Clause 51. The UE of any one of clauses 41 to 50, wherein the reservation message comprises a priority indication.

[0178] Clause 52. The UE of any of clauses 41 to 51, wherein the reservation message comprises timing information related to the reservation of the RPP.

[0179] Clause 53. The UE of clause 52, wherein the timing information relating to the reservation of the RPP comprises a start time of the RPP, an end time of the RPP, a time offset of the RPP, a periodicity of the RPP, an indicator that the RPP does not repeat, or a combination thereof.

[0180] Clause 54. The UE of any of clauses 41 to 53, wherein the reservation message comprises a request that at least one other UE reduce interference during the reserved RPP.

[0181] Clause 55. The UE of Clause 54, wherein the at least one processor configured to reduce interference comprises the at least one processor configured to perform rate matching, muting, puncturing, reducing transmit power, or a combination thereof.

[0182] Clause 56. The UE of any one of clauses 41 to 55, wherein the UE comprises a relay UE associated with a remote UE.

[0183] Clause 57. The UE of clause 56, wherein the at least one processor is further configured to receive a request from a remote UE for an RPP from the predetermined plurality of RPPs, and determining that an RPP from the predetermined plurality of RPPs should be reserved is based on receiving the request.

[0184] Clause 58. The UE of clause 57, wherein the request identifies a particular RPP from a predetermined plurality of RPPs.

[0185] Clause 59. The UE of clause 58, wherein the reservation message indicates a reservation for a particular RPP identified in the request.

[0186] Clause 60. The UE of any of clauses 58-59, wherein the reservation message indicates a reservation for an RPP different from the particular RPP identified in the request.

[0187] Clause 61. The UE of any of clauses 56-60, wherein the at least one processor is further configured to cause the at least one transceiver to transmit to the remote UE an RPP configuration identifying a reserved RPP to be used by the remote UE.

[0188] Clause 62. The UE of clause 61, wherein the RPP configuration identifies sidelink positioning reference signal (SL-PRS) resources within the reserved RPP.

[0189] Clause 63. The UE of clause 62, wherein the SL-PRS resource in the reserved RPP is identified by an index.

[0190] Clause 64. The UE of any of clauses 62-63, wherein the identified SL-PRS resources comprise all or part of the SL-PRS resources in the reserved RPP.

[0191] Clause 65. 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, wherein the at least one processor is configured to receive a reservation message indicating a reservation of an RPP from a predetermined plurality of RPPs for use by a second UE, and to modify an intended transmission during the reserved RPP to reduce interference with the second UE.

[0192] Clause 66. The UE of Clause 65, wherein the at least one processor configured to modify the intended transmission comprises the at least one processor configured to perform rate matching, muting, puncturing, reducing transmit power, or a combination thereof.

[0193] Clause 67. The UE of any one of clauses 65 to 66, wherein the predetermined plurality of RPPs are preloaded.

[0194] Clause 68. The UE of any one of clauses 65 to 67, wherein the predetermined plurality of RPPs are configured by the serving base station.

[0195] Clause 69. The UE of any of clauses 65 to 68, wherein the reservation message is received via a broadcast message, a groupcast message, or a multicast message.

[0196] Clause 70. The UE of any of clauses 65 to 69, wherein the reservation message is received via a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), or a combination thereof.

[0197] Clause 71. The UE of any of clauses 65 to 70, wherein the reservation message indicates that a sidelink positioning reference signal (SL-PRS) is to be transmitted using the reserved RPP.

[0198] Clause 72. The UE of any of clauses 65 to 71, wherein the reservation message identifies a second UE that uses the reserved RPP.

[0199] Clause 73. The UE of any one of clauses 65 to 72, wherein the reservation message comprises an RPP identifier.

[0200] Clause 74. The UE of any one of clauses 65 to 73, wherein the reservation message comprises a zone identifier.

[0201] Clause 75. The UE of any of clauses 65 to 74, wherein the reservation message comprises a priority indication.

[0202] Clause 76. The UE of any of clauses 65 to 75, wherein the reservation message comprises timing information related to the reservation of the RPP.

[0203] Clause 77. The UE of clause 76, wherein the timing information relating to the reservation of the RPP comprises a start time of the RPP, an end time of the RPP, a time offset of the RPP, a periodicity of the RPP, an indicator that the RPP does not repeat, or a combination thereof.

[0204] Clause 78. The UE of any of clauses 65 to 77, wherein the reservation message identifies sidelink positioning reference signal (SL-PRS) resources within the reserved RPP.

[0205] Clause 79. The UE of clause 78, wherein the SL-PRS resource in the reserved RPP is identified by an index.

[0206] Clause 80. The UE of any of clauses 78-79, wherein the identified SL-PRS resources comprise all or part of the SL-PRS resources in the reserved RPP.

[0207] Clause 81. An apparatus comprising a memory and at least one processor communicatively coupled to the memory, wherein the memory and the at least one processor are configured to perform a method according to any of clauses 1 to 80.

[0208] Clause 82. Apparatus comprising means for carrying out the method according to any of clauses 1 to 80.

[0209] Clause 83. A non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions comprising at least one instruction for causing a computer or processor to perform a method according to any of clauses 1 to 80.

[0210] Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, the 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.

[0211] Furthermore, those skilled 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 a combination 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 on the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in various ways for each particular application, but such aspect decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0212] The various example logic blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed using a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0213] The methods, sequences, and / or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in software modules executed by a processor, or in a combination of the two. The software modules 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, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. Alternatively, 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). Alternatively, the processor and the storage medium may reside as discrete components in the user terminal.

[0214] In one or more exemplary 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. Storage media may be any available medium that can be accessed by a computer. By way of example, and not limitation, such computer-readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that 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 software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of medium. Disk and disc, as used herein, include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks typically reproduce data magnetically and discs reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0215] While the above disclosure illustrates exemplary aspects of the present disclosure, it should be noted that various changes and modifications can be made herein without departing from the scope of the present disclosure as defined by the appended claims. The functions, steps, and / or actions of the method claims in accordance with the aspects of the present disclosure described herein need not be performed in any particular order. Furthermore, although elements of the present disclosure may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. [Explanation of symbols]

[0216] 100 Wireless Communication System 102 Base station 104 User Equipment (UE) 110 Geographic Coverage Areas 112 Space Vehicle (SV) 120 Communication Links 122 backhaul links 124 SPS communication links 134 backhaul links 150 Wireless Local Area Network (WLAN) Access Points (APs) 152 Wireless Local Area Network (WLAN) Station (STA), User Equipment (UE) 154 communication links 160V-UE 162 Wireless Sidelink 164 Roadside Access Points 166 Wireless Sidelink 168 Wireless Sidelink 172 Location Server 174 Core Network 180 mmW base station 182 User Equipment (UE) 184 mmW communication link 190 User Equipment (UE) 192, 194 D2D P2P links 200 Wireless Network Structure 204 User Equipment (UE) 210 5GC 212 User Plane Functions 213 User Plane Interface (NG-U) 214 Control Plane Functions 215 Control Plane Interface (NG-C) 220 Next Generation RAN (NG-RAN) 222 gNB 223 Backhaul Connection 224 ng-eNB 230 Location Server 242 Wireless Sidelink 250 Wireless Network Structure 260 5GC 262 User Plane Function (UPF) 263 User Plane Interface 264 Access and Mobility Management Function (AMF) 265 Control Plane Interface 266 Session Management Facility (SMF) 270 LMF 272 SLP 300 Wireless Communication System 302 First UE 304 Second UE 305 Sidelink Signaling Radio Bearer 310 Sidelink Signaling Radio Bearer 315 Connection Request 320 Connect 325 Connection Established 330 Side Link 335 Sidelink Data 502 User Equipment (UE) 504 base station 506 Network Entity 510 Wireless Wide Area Network (WWAN) Transceiver 512 receiver 514 Transmitter 516 Antenna 518 Signal 520 Short Range Wireless Transceiver 522 receiver 524 Transmitter 526 Antenna 528 signal 530 Satellite Positioning System (SPS) Receiver 532 Processing System 534 Data Bus 536 Antenna 538 SPS signal 540 Memory Components 542 Sidelink Manager 544 Sensors 546 User Interface 550 Wireless Wide Area Network (WWAN) Transceiver 552 receiver 554 Transmitter 556 Antenna 558 Signal 560 Short-Range Wireless Transceiver 562 receiver 566 Antenna 568 signal 570 Satellite Positioning System (SPS) Receiver 576 Antenna 578 SPS signal 580 network interface 582 Data Bus 584 Processing System 586 Memory Components 588 Sidelink Manager 590 Network Interface 592 Data Bus 594 Processing System 596 Memory Components 598 Sidelink Manager 600 relay UE 602 Remote UE 604 Base Station 606 Relay UE

Claims

1. 1. A method of wireless communication performed by a user equipment (UE), comprising: determining that a positioning resource pool (RPP) from a plurality of predefined RPPs should be reserved; sending a reservation message to at least one other UE indicating a reservation of an RPP from the predetermined plurality of RPPs; A method for providing

2. The method of claim 1 , wherein the predetermined plurality of RPPs are preloaded or configured by a serving base station.

3. 2. The method of claim 1, wherein determining that an RPP from the predetermined plurality of RPPs should be reserved comprises selecting an RPP from the predetermined plurality of RPPs.

4. The reservation message is transmitted via a broadcast, groupcast, or multicast message; and / or 2. The method of claim 1, wherein the reservation message is transmitted via a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), or a combination thereof.

5. the reservation message indicates that a Sidelink Positioning Reference Signal (SL-PRS) will be transmitted using the reserved RPP; and / or The method of claim 1 , wherein the reservation message identifies a remote UE that uses the reserved RPP.

6. The method of claim 1 , wherein the reservation message comprises one or more of an RPP identifier, a zone identifier, and a priority indication.

7. the reservation message comprises timing information associated with the reservation; 2. The method of claim 1, wherein the timing information associated with the reservation comprises a start time of the RPP, an end time of the RPP, a time offset of the RPP, a periodicity of the RPP, an indicator that the RPP does not repeat, or a combination thereof.

8. the reservation message comprises a request that the at least one other UE reduce interference during the reserved RPP; 10. The method of claim 1, wherein reducing interference comprises rate matching, muting, puncturing, reducing transmit power, or a combination thereof.

9. The method of claim 1 , wherein the UE comprises a relay UE associated with a remote UE.

10. receiving a request from the remote UE for an RPP from the predetermined plurality of RPPs; determining an RPP from the predetermined plurality of RPPs based on receiving the request; the request identifies a particular RPP from the predetermined plurality of RPPs; 10. The method of claim 9, wherein the reservation message indicates a reservation for the particular RPP identified in the request, or wherein the reservation message indicates a reservation for an RPP different from the particular RPP identified in the request.

11. sending an RPP configuration to the remote UE identifying the reserved RPP to be used by the remote UE; the RPP configuration identifies sidelink positioning reference signal (SL-PRS) resources within the reserved RPP; 10. The method of claim 9, wherein the SL-PRS resources in the reserved RPP are identified by an index and / or the identified SL-PRS resources comprise all or a portion of the SL-PRS resources in the reserved RPP.

12. 1. A method of wireless communication performed by a user equipment (UE), comprising: receiving a reservation message indicating a reservation of an RPP from a predetermined plurality of RPPs for use by a second UE; modifying an intended transmission to reduce interference with the second UE during the reserved RPP; A method for providing

13. A user equipment (UE), Memory and 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: determining that a positioning resource pool (RPP) from a plurality of predetermined RPPs should be reserved; causing the at least one transceiver to transmit a reservation message to at least one other UE indicating a reservation of an RPP from the predetermined plurality of RPPs. A user equipment (UE) configured to:

14. A user equipment (UE), Memory and 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: receiving a reservation message indicating a reservation of an RPP from a predetermined plurality of RPPs for use by a second UE; Modifying an intended transmission to reduce interference with the second UE during the reserved RPP. A user equipment (UE) configured to:

15. A computer program product for causing a computer or processor to carry out the method of any one of claims 1 to 11.

16. A computer program product for causing a computer or processor to carry out the method of claim 12.

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