Sidelink positioning status determination and reporting

Abstract

Techniques for wireless communications are disclosed. In one aspect, a user equipment (UE) receives a configuration of a first set of sidelink positioning reference signal (SL-PRS) resources configured for transmission by a first set of sidelink UEs including the UE, and determines a sidelink transmission status of a first subset of SL-PRS resources of the first set of SL-PRS resources based on signal strength measurements of the first set of SL-PRS resources, availability information for the first set of SL-PRS resources, or both. The sidelink transmission status of a given UE may also be inferred from configuration information associated with the given UE and received at the UE.

Description

[Technical field]

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

[0002] 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, many different types of wireless communication systems are in use, including cellular systems and personal communications service (PCS) systems. Examples of known cellular systems include the cellular analog advanced mobile phone system (AMPS), and digital cellular systems based on code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), Global System for Mobile communications (GSM), and the like.

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

[0004] In particular, taking advantage of 5G's increased data rates and reduced latency, device-to-device communication technologies are being implemented to support wireless communications between vehicles, between vehicles and roadside infrastructure, between vehicles and pedestrians, between personal devices, etc. Summary of the Invention

[0005] The following presents a simplified summary of one or more aspects disclosed herein. As such, the following summary is not intended to be an extensive overview of all contemplated aspects, nor is it intended to identify key or critical elements of all contemplated aspects or to delineate the scope of any particular aspect. Thus, the sole purpose of the following summary is to present certain concepts of one or more aspects of the mechanisms disclosed herein in a simplified form prior to the detailed description presented below.

[0006] In one aspect, a method of wireless communication performed by a user equipment (UE) includes receiving a configuration of a first set of sidelink positioning reference signal (SL-PRS) resources configured for transmission by a first set of sidelink UEs including the UE, and determining a sidelink transmission status of a first subset of SL-PRS resources of the first set of SL-PRS resources based on signal strength measurements of the first set of SL-PRS resources, availability information for the first set of SL-PRS resources, or both.

[0007] In one aspect, a method of wireless communication performed by a user equipment (UE) includes receiving configuration information associated with a location-based discontinuous reception (DRX) mode, acquiring a location of the UE, and transmitting a sidelink positioning reference signal (SL-PRS) based on the location while in an inactive state of the location-based DRX mode.

[0008] In one aspect, a method of wireless communication performed by a user equipment (UE) includes receiving a request to transmit an on-demand sidelink position reference signal (SL-PRS) along with a time period during which the UE is requested to transmit the on-demand SL-PRS, refraining from transmitting, receiving, or both over a transmission channel, a reception channel, or both that conflicts with the requested on-demand SL-PRS, and transmitting the requested on-demand SL-PRS.

[0009] In one aspect, a user equipment (UE) includes a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, wherein the at least one processor is configured to receive via the at least one transceiver a configuration of a first set of sidelink positioning reference signal (SL-PRS) resources configured for transmission by a first set of sidelink UEs, and to determine a sidelink transmission status of a first subset of the SL-PRS resources of the first set of SL-PRS resources based on signal strength measurements of the first set of SL-PRS resources, availability information of the first set of SL-PRS resources, or both.

[0010] In one aspect, a user equipment (UE) includes a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, wherein the at least one processor is configured to receive, via the at least one transceiver, configuration information associated with a location-based discontinuous reception (DRX) mode, obtain a location of the UE, and transmit, via the at least one transceiver, a sidelink positioning reference signal (SL-PRS) based on the location while in an inactive state of the location-based DRX mode.

[0011] In one aspect, a user equipment (UE) includes a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, where the at least one processor is configured to receive a request to transmit an on-demand sidelink position reference signal (SL-PRS) via the at least one transceiver along with a time period during which the UE is requested to transmit the SL-PRS, refrain from transmitting, receiving, or both via a transmission channel, a reception channel, or both that conflicts with the requested on-demand SL-PRS, and transmit the requested SL-PRS via the at least one transceiver.

[0012] In one aspect, a user equipment (UE) includes means for receiving a configuration of a first set of sidelink positioning reference signal (SL-PRS) resources configured for transmission by a first set of sidelink UEs, and means for determining a sidelink transmission status of a first subset of the SL-PRS resources based on signal strength measurements of the first set of SL-PRS resources, availability information of the first set of SL-PRS resources, or both.

[0013] In one aspect, a user equipment (UE) includes means for receiving configuration information associated with a location-based discontinuous reception (DRX) mode, means for obtaining a location of the UE, and means for transmitting a sidelink positioning reference signal (SL-PRS) based on the location while in an inactive state of the location-based DRX mode.

[0014] In one aspect, a user equipment (UE) includes means for receiving a request to transmit an on-demand sidelink position reference signal (SL-PRS) along with a time period during which the UE is requested to transmit the SL-PRS, means for refraining from transmitting, receiving, or both over a transmission channel, a reception channel, or both that conflicts with the requested on-demand SL-PRS, and means for transmitting the requested on-demand SL-PRS.

[0015] In one aspect, a non-transitory computer-readable medium stores computer-executable instructions that, when executed by a user equipment (UE), cause the UE to receive a configuration of a first set of Sidelink Positioning Reference Signal (SL-PRS) resources configured for transmission by a first set of sidelink UEs and determine a sidelink transmission status of a first subset of the SL-PRS resources based on signal strength measurements of the first set of SL-PRS resources, availability information for the first set of SL-PRS resources, or both.

[0016] In an aspect, a non-transitory computer-readable medium stores computer-executable instructions that, when executed by a user equipment (UE), cause the UE to receive configuration information associated with a location-based discontinuous reception (DRX) mode, obtain a location of the UE, and transmit a sidelink positioning reference signal (SL-PRS) based on the location while in an inactive state of the location-based DRX mode.

[0017] In one aspect, a non-transitory computer-readable medium stores computer-executable instructions that, when executed by a user equipment (UE), cause the UE to receive a request to transmit an on-demand sidelink position reference signal (SL-PRS) along with a time period during which the UE is requested to transmit the on-demand SL-PRS, refrain from transmitting, receiving, or both over a transmit channel, receive channel, or both that conflicts with the requested on-demand SL-PRS, and transmit the requested on-demand SL-PRS.

[0018] 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.

[0019] The accompanying drawings are presented to aid in the description of various aspects of the present disclosure and are provided only to illustrate, not limit, the aspects. [Brief description of the drawings]

[0020] [Figure 1] 1 illustrates an example wireless communication system according to an aspect of the present disclosure. [Figure 2A] 1 illustrates an exemplary wireless network structure in accordance with an aspect of the present disclosure. [Figure 2B] 1 illustrates an exemplary wireless network structure in accordance with an aspect of the present disclosure. [Figure 2C] 1 illustrates an exemplary wireless network structure in accordance with an aspect of the present disclosure. [Figure 3A]1 is a simplified block diagram of several sample aspects of components that may be employed in a user equipment (UE), a base station, and a network entity, respectively, and configured to support communications as taught herein. [Figure 3B] 1 is a simplified block diagram of several sample aspects of components that may be employed in a user equipment (UE), a base station, and a network entity, respectively, and configured to support communications as taught herein. [Figure 3C] 1 is a simplified block diagram of several sample aspects of components that may be employed in a user equipment (UE), a base station, and a network entity, respectively, and configured to support communications as taught herein. [Figure 4] 1 illustrates an example wireless communication system in which a vehicle user equipment (V-UE) is exchanging ranging signals with a roadside unit (RSU) and another V-UE, in accordance with an aspect of the present disclosure. [Diagram 5] 1 illustrates examples of various positioning methods supported in New Radio (NR) according to an embodiment of the present disclosure. [Figure 6A] 1 illustrates various scenarios of interest for sidelink-only or joint Uu and sidelink positioning, in accordance with aspects of the present disclosure. [Figure 6B] 1 illustrates various scenarios of interest for sidelink-only or joint Uu and sidelink positioning, in accordance with aspects of the present disclosure. [Figure 7] FIG. 2 illustrates an example frame structure according to an aspect of the present disclosure. [Figure 8A] FIG. 1 is a diagram of an example sidelink slot structure with and without feedback resources in accordance with an aspect of the disclosure. [Figure 8B] FIG. 1 is a diagram of an example sidelink slot structure with and without feedback resources in accordance with an aspect of the disclosure. [Figure 9]FIG. 1 illustrates an example resource pool for positioning within a sidelink resource pool, according to an aspect of the present disclosure. [Figure 10] FIG. 1 illustrates an example process for scheduling sidelink resources according to an aspect of the present disclosure. [Figure 11] 1 illustrates an example scenario for sidelink activity, in accordance with an aspect of the present disclosure. [Figure 12A] 1 illustrates an example discontinuous reception (DRX) configuration in accordance with an aspect of the present disclosure. [Figure 12B] 1 illustrates an example discontinuous reception (DRX) configuration in accordance with an aspect of the present disclosure. [Figure 12C] 1 illustrates an example discontinuous reception (DRX) configuration in accordance with an aspect of the present disclosure. [Figure 13] FIG. 1 illustrates an example of a positioning method using DRX according to an embodiment of the present disclosure. [Figure 14] 1 is a diagram of an example connection scenario of devices near a wireless unit, according to an aspect of the present disclosure. [Figure 15] 1 illustrates an example method of wireless communication according to an aspect of the present disclosure. [Figure 16] 1 illustrates an example method of wireless communication according to an aspect of the present disclosure. [Figure 17] 1 illustrates an example method of wireless communication according to an aspect of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Aspects of the present disclosure are provided in the following description and associated 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 specifically described or will be omitted so as not to obscure the relevant details of the present disclosure.

[0022] 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.

[0023] 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, desired design, corresponding technology, etc.

[0024] 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 appreciated that various actions described herein can be performed by specific circuitry (e.g., application specific integrated circuits (ASICs)), by program instructions executed by one or more processors, or by a combination of both. In addition, the sequence or sequences of actions described herein can be considered to be fully embodied in any form of non-transitory computer-readable storage medium storing a corresponding set of computer instructions that, when executed, cause or instruct an associated processor of a device to perform the functionality described herein. Thus, 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. In addition, for each of the aspects described herein, the corresponding form of any such aspect may be described herein, for example, as "logic configured to" perform the described actions.

[0025] The terms "user equipment" (UE), "vehicle UE" (V-UE), "pedestrian UE" (P-UE), and "base station" as used herein are not intended to be specific 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 computer installed in a vehicle, a vehicle navigation device, a mobile phone, a router, a tablet computer, a laptop computer, an asset positioning device, a wearable (e.g., a smart watch, a smart glass, an augmented reality (AR) / virtual reality (VR) headset, etc.), a vehicle (e.g., a car, 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 a certain time) 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.

[0026] A V-UE is a type of UE and may be any in-vehicle wireless communication device, such as a navigation system, a warning system, a heads-up display (HUD), an on-board computer, an in-vehicle infotainment system, an automated driving system (ADS), an advanced driver assistance system (ADAS), etc. Alternatively, a V-UE may be a portable wireless communication device (e.g., a mobile 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 may communicate with a core network via a RAN, through which the UE may be connected to external networks such as the Internet and to other UEs. Of course, other mechanisms for a UE to connect to the core network and / or the Internet are possible, such as via a wired access network, a wireless local area network (WLAN) network (e.g., based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11, etc.), etc.

[0027] Depending on the network in which the base station is deployed, the base station may operate according to one of several RATs in communication with the UE 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. The base station may be used primarily to support wireless access by the UE, including supporting data, voice, and / or signaling connections for supported UEs. In some systems, the base station may provide only edge node signaling functions, while in other systems the base station may provide additional control and / or network management functions. The communication link through which the UE can send signals to the base station is referred to as an uplink (UL) channel (e.g., reverse traffic channel, reverse control channel, access channel, etc.). The communication links through which a base station may transmit signals to a UE are called downlink (DL) or forward link channels (e.g., paging, control, broadcast, forward traffic, etc.). As used herein, the term traffic channel (TCH) can refer to either a UL / reverse traffic channel or a DL / forward traffic channel.

[0028] The term "base station" may refer to a single physical transmission-reception point (TRP) or multiple physical TRPs that 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 that corresponds to a cell (or several cell sectors) of the base station. When the term "base station" refers to multiple collocated physical TRPs, the physical TRP 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 TRP 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, non-co-located physical TRPs may be serving base stations that receive measurement reports from the UE and neighboring base stations whose reference radio frequency (RF) signals the UE is measuring. Since a TRP is a point from which a base station transmits and receives wireless signals, as used herein, references to transmission from or reception at a base station should be understood as referring to a particular TRP of the base station.

[0029] In some implementations that support positioning of UEs, a base station may not support wireless access by the UE (e.g., may not support data, voice, and / or signaling connections 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 it transmits RF signals to the UE) and / or a location measurement unit (e.g., when it receives and measures RF signals from the UE).

[0030] An "RF signal" includes electromagnetic waves of a given frequency that propagate 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, the receiver may receive multiple "RF signals" corresponding to each transmitted RF signal due to the propagation characteristics of RF signals through multipath channels. The same 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.

[0031] 1 illustrates an example wireless communication system 100 according to an aspect of the disclosure. The wireless communication system 100 (sometimes referred to as a wireless wide area network (WWAN)) may include various base stations 102 (labeled as "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 an aspect, the macrocell base stations 102 may include eNBs and / or ng-eNBs where the wireless communication system 100 supports an LTE network, or gNBs where the wireless communication system 100 supports an NR network, or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, etc.

[0032] The base stations 102 collectively form the RAN and may interface to a core network 170 (e.g., evolved packet core (EPC) or 5G core (5GC)) via backhaul links 122, and to one or more location servers 172 (e.g., location management function (LMF) or secure user plane location (SUPL) location platform (SLP)) via the core network 170. The location server(s) 172 may be part of the core network 170 or may be external to the core network 170. The location server 172 may be integrated with the base station 102. The UE 104 may communicate with the location server 172 directly or indirectly. For example, the UE 104 may communicate with the location server 172 via the base station 102 currently serving the UE 104. The UE 104 may also communicate with the location server 172 through another path, such as through an application server (not shown), through another network, such as through a wireless local area network (WLAN) access point (AP) (e.g., AP 150 described below), etc. For purposes of signaling, communication between the UE 104 and the location server 172 may be represented as an indirect connection (e.g., through the core network 170), or a direct connection (e.g., as shown via direct connection 128), with intervening nodes (if any) omitted from the signaling diagrams for clarity.

[0033] 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, non-access stratum (NAS) message delivery, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracing, RAN information management (RIM), paging, positioning, and alert message delivery. 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.

[0034] 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., a physical cell identifier (PCI), an enhanced cell identifier (ECI), a virtual cell identifier (VCI), a cell global identifier (CGI), etc.) to distinguish 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 cells are supported by a particular base station, the term "cell" may refer to either or both of the logical communication entity supporting the cell and the base station, depending on the context. In some cases, the term "cell" may also refer to the geographic coverage area (e.g., sector) of a base station, so long as the carrier frequency can be detected and used for communication within a portion of the geographic coverage area 110.

[0035] The geographic coverage areas 110 of neighboring macrocell base stations 102 may overlap partially (e.g., in 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 known as a heterogeneous network. A heterogeneous network may also include home eNBs (HeNBs), which may serve closed groups known as closed subscriber groups (CSGs).

[0036] The communication link 120 between the base station 102 and the UE 104 may include uplink (also referred to as reverse link) transmissions from the UE 104 to the base station 102, and / or downlink (DL) (also referred to as 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 with respect to the downlink and uplink (e.g., more or fewer carriers may be allocated for the downlink than for the uplink).

[0037] The wireless communication system 100 may further include a wireless local area network (WLAN) access point (AP) 150 in communication with wireless local area network (WLAN) stations (STAs) 152 over a communication link 154 in an unlicensed frequency spectrum (e.g., 5 GHz). When communicating in the unlicensed frequency spectrum, the WLAN STAs 152 and / or the WLAN AP 150 may perform a clear channel assessment (CCA) or listen before talk (LBT) procedure before communicating to determine if a channel is available.

[0038] 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 utilize LTE or NR technology and employ 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 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 MulteFire.

[0039] The wireless communication system 100 may further include a mmW base station 180 that may operate at millimeter wave (mmW) and / or sub-mmW frequencies while communicating with the UE 182. Extremely high frequency (EHF) is a portion of RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength of 1 millimeter to 10 millimeters. Radio waves in this band may be referred to as millimeter waves. Sub-mmW may go down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band ranges from 3 GHz to 30 GHz and is also referred to as centimeter wave. Communications using the mmW / sub-mmW radio frequency bands have high path loss and relatively short range. 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 extremely high path loss and short range. It will be further understood that in alternative configurations, one or more base stations 102 may also transmit using mmW or quasi-mmW and beamforming. Accordingly, it will be understood that the above illustrations are merely examples and should not be construed as limiting various aspects disclosed herein.

[0040] Transmit beamforming is a technique for concentrating an RF signal in a particular direction. Traditionally, when a network node (e.g., a base station) broadcasts an RF signal, it broadcasts it in all directions (omnidirectional). With transmit beamforming, the network node determines where a given target device (e.g., UE) is located (relative to the transmitting network node) and launches a stronger downlink RF signal in that particular direction, thereby providing a faster and more powerful RF signal (in terms of data rate) to the receiving device(s). 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 the one or more transmitters broadcasting the RF signal. For example, the network node may use an array of antennas (also called a "phased array" or "antenna array") that creates beams of RF waves that can be "steered" to point in different directions without actually moving the antennas. Specifically, RF currents from the transmitters are fed to the individual antennas with the proper phase relationship so that the radio waves from the separate antennas are combined to cancel and suppress radiation in undesired directions while simultaneously enhancing radiation in desired directions.

[0041] A transmit beam may be quasi-co-located, meaning that the transmit beam appears to a receiver (e.g., UE) to have the same parameters regardless of whether the network node's own transmit antenna is physically co-located or not. In NR, there are four types of quasi-co-location (QCL) relationships. Specifically, 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, average 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.

[0042] 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 array of antennas in a particular direction to amplify (e.g., increase its gain level) an RF signal 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 higher than the beam gains along other directions, or that the beam gain in that direction is the highest 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 the RF signal received from that direction.

[0043] The transmit beam and the receive beam may be spatially related. The spatial relationship means that the parameters for the second beam (e.g., transmit beam or receive beam) for the second reference signal may be derived from information about the first beam (e.g., receive beam or transmit beam) for the first reference signal. For example, the UE may use a particular receive beam to receive a reference downlink reference signal (e.g., synchronization signal block (SSB)) from a base station. The UE may then form a transmit beam for sending an uplink reference signal (e.g., sounding reference signal (SRS)) to that base station based on the parameters of the receive beam.

[0044] Note that a "downlink" beam can be either a transmit beam or a receive beam, depending on the entity that forms it. For example, if the base station forms a downlink beam to transmit a reference signal to the UE, then the downlink beam is a transmit beam. However, if the UE forms a downlink beam, then it is a receive beam to receive a downlink reference signal. Similarly, an "uplink" beam can be either a transmit beam or a receive beam, depending on the entity that forms it. For example, if the base station forms an uplink beam, then it is an uplink receive beam, and if the UE forms an uplink beam, then it is an uplink transmit beam.

[0045] The electromagnetic spectrum is often subdivided into various classes, bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). It should be understood that FR1 is often referred to (interchangeably) as the "sub-6 GHz" band in various documents and papers, although a portion of FR1 is above 6 GHz. A similar nomenclature issue may arise with respect to FR2, which is often referred to (interchangeably) as the "millimeter wave" band in documents and papers, even though it is different from the extremely high frequency (EHF) band (30 GHz-300 GHz) identified as the "millimeter wave" band by the International Telecommunications Union (ITU).

[0046] Frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Recent 5G NR studies have identified operating bands for these mid-band frequencies as frequency range designation FR3 (7.125 GHz to 24.25 GHz). Frequency bands included within FR3 may inherit FR1 and / or FR2 characteristics, and thus may in effect extend the features of FR1 and / or FR2 to the mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operation beyond 52.6 GHz. For example, three higher operating bands have been identified as frequency range designations FR4a or FR4-1 (52.6 GHz to 71 GHz), FR4 (52.6 GHz to 114.25 GHz), and FR5 (114.25 GHz to 300 GHz). Each of these higher frequency bands is included within the EHF band.

[0047] With the above aspects in mind, it should be understood that unless specifically stated otherwise, terms such as "sub-6 GHz" as used herein may broadly refer to frequencies that may be below 6 GHz, may be within FR1, or may include mid-band frequencies. Furthermore, unless specifically stated otherwise, it should be understood that terms such as "mmWave" as used herein may broadly refer to frequencies that may include mid-band frequencies, may be within the ranges of FR2, FR4, FR4-a or FR4-1, and / or FR5, or may be within the EHF band.

[0048] In a multi-carrier system such as 5G, one of the carrier frequencies is called the "primary carrier" or "anchor carrier" or "primary serving cell" or "PCell", and the remaining carrier frequencies are called the "secondary carrier" or "secondary serving cell" or "SCell". In carrier aggregation, the anchor carrier is a carrier operating on a primary frequency (e.g., FR1) utilized by the UE 104 / 182 and the cell where the UE 104 / 182 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 (but is not always) be a carrier among licensed frequencies. 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. Since both the primary uplink carrier and the primary downlink carrier are typically UE specific, the secondary carrier shall contain only the necessary signaling information and signals, e.g., there should be no UE specific signaling information and signals in the secondary carrier. This means that different UEs 104 / 182 in a cell may have different downlink primary carriers. The same applies to 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. Since 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", "carrier frequency" and the like may be used interchangeably.

[0049] For example, still referring to FIG. 1, one of the frequencies utilized by the macrocell base station 102 may be an anchor carrier (or "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 reception rates. For example, two 20 MHz carriers aggregated in a multi-carrier system would theoretically provide a two-fold increase in data rate (i.e., 40 MHz) compared to the data rate achieved by a single 20 MHz carrier.

[0050] In the example of FIG. 1, any of the illustrated UEs (shown in FIG. 1 as a single UE 104 for simplicity) may receive signals 124 from one or more Earth-orbiting space vehicles (SVs) 112 (e.g., satellites). In one aspect, the SVs 112 may be part of a satellite positioning system that the UE 104 may use as an independent source of location information. A satellite positioning system typically includes a system of transmitters (e.g., SVs 112) positioned to enable receivers (e.g., UEs 104) to determine their location on or above the Earth based at least in part on positioning signals (e.g., signals 124) received from the transmitters. Such transmitters typically transmit signals marked with a repeating pseudo-random noise (PN) code of a set number of chips. Although typically located within the SVs 112, transmitters may sometimes be located on ground-based control stations, base stations 102, and / or other UEs 104. The UE 104 may include one or more dedicated receivers specifically designed to receive the signals 124 from the SV 112 to derive geolocation information.

[0051] In a satellite positioning system, the use of the 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, the SBAS may include augmentation systems that provide integrity information, error correction, and the like, such as the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay Service (EGNOS), the Multi-functional 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, a satellite positioning system may include any combination of one or more global and / or regional navigation satellites associated with such one or more satellite positioning systems.

[0052] In one aspect, the SV 112 may additionally or alternatively be part of one or more non-terrestrial networks (NTNs). In an NTN, the SV 112 is connected to an earth station (also called a ground station, NTN gateway, or gateway), which in turn is connected to an element in a 5G network, such as a modified base station 102 (without a terrestrial antenna) or a network node in a 5G network. This element will then provide access to other elements in the 5G network and ultimately to entities outside the 5G network, such as Internet web servers and other user devices. In that way, the UE 104 may receive communication signals (e.g., signal 124) from the SV 112 instead of or in addition to communication signals from the terrestrial base station 102.

[0053] In particular, vehicle-to-everything (V2X) communication technology is being implemented to leverage NR’s increased data rates and reduced latency to support intelligent transportation 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 will enable safety, mobility, and environmental improvements that current technologies cannot provide. When fully implemented, the technology is expected to reduce unimpeded vehicle collisions by 80%.

[0054] 1, the wireless communication system 100 may include multiple V-UEs 160 that may communicate with the base station 102 over the communication link 120 using the Uu interface (i.e., the air interface between the UE and the base station). The V-UEs 160 may also communicate with each other directly over a wireless sidelink 162, with a roadside unit (RSU) 164 (a roadside access point) over a wireless sidelink 166, or with a sidelink-enabled UE 104 over a wireless sidelink 168 using a PC5 interface (i.e., the air interface between sidelink-enabled UEs). The wireless sidelink (or simply "sidelink") is an adaptation of the core cellular (e.g., LTE, NR) standard that allows direct communication between two or more UEs without the communication having to go through a base station. Sidelink communications may be unicast or multicast and may be used for device-to-device (D2D) medium sharing, V2V communications, V2X communications (e.g., cellular V2X (cV2X) communications, enhanced V2X (eV2X) communications, etc.), emergency rescue applications, etc. One or more of the groups 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 all other V-UEs 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.

[0055] In one aspect, the sidelinks 162, 166, 168 may operate over a subject wireless communications medium, which may be shared with other vehicles and / or infrastructure access points, as well as other wireless communications between other RATs. The "medium" may be comprised of one or more time, frequency, and / or spatial communications resources (e.g., encompassing one or more channels across one or more carriers) associated with wireless communications between one or more transmitter / receiver pairs.

[0056] In one aspect, the sidelinks 162, 166, 168 may be cV2X links. First generation cV2X is 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 in licensed ITS bands in the sub-6 GHz. 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.

[0057] 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 communications protocol using the wireless access for vehicular environments (WAVE) protocol, also referred to as IEEE 802.11p, for V2V, V2I, and V2P communications. IEEE 802.11p is an approved amendment to the IEEE 802.11 standard, which 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 countries may allocate other bands. The V2V communications briefly described above are typically conducted on the Safety Channel, a 10 MHz channel dedicated for safety purposes in the United States. The remainder of the DSRC band (total bandwidth of 75 MHz) is intended for other services targeted to drivers, such as road enforcement, toll collection, automated parking, etc. Thus, as a specific example, the medium of interest utilized by the sidelinks 162, 166, 168 may correspond to at least a portion of the 5.9 GHz licensed ITS frequency band.

[0058] Alternatively, the medium of interest may correspond to at least a portion of an unlicensed frequency band shared among various RATs. Although different licensed frequency bands have been reserved for several 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 their 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 CDMA systems, TDMA systems, FDMA systems, orthogonal FDMA (OFDMA) systems, single-carrier FDMA (SC-FDMA) systems, and various variants thereof.

[0059] The communication between V-UEs 160 is referred to as V2V communication, the communication between V-UEs 160 and one or more RSUs 164 is referred to as V2I communication, and the communication between V-UEs 160 and one or more UEs 104 (where UEs 104 are P-UEs) is referred to as V2P communication. The V2V communication between V-UEs 160 may include, for example, information about the position, speed, acceleration, heading, and other vehicle data of the V-UEs 160. The V2I information received at the V-UEs 160 from one or more RSUs 164 may include, for example, road regulations, parking automation information, and the like. The V2P communication between V-UEs 160 and UEs 104 may include, for example, information about the position, speed, acceleration, and heading of the V-UEs 160, and the position, speed (e.g., when the UEs 104 are carried by a user on a bicycle), and heading of the UEs 104.

[0060] It should be noted 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 being connected via a sidelink, any of the UEs illustrated in FIG. 1, whether V-UE, P-UE, etc., may be capable of sidelink communication. Additionally, although only UE 182 was described as being capable of beamforming, any of the illustrated UEs, including V-UE 160, may be capable of beamforming. If V-UEs 160 are capable of beamforming, they may beamform toward each other (i.e., toward other V-UEs 160), toward RSU 164, toward other UEs (e.g., UEs 104, 152, 182, 190), etc. Thus, in some cases, V-UE 160 may utilize beamforming on sidelinks 162, 166, and 168.

[0061] 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 (e.g., through which the UE 190 may indirectly obtain cellular connectivity) with one of the UEs 104 connected to one of the base stations 102, and a D2D P2P link 194 (through which the UE 190 may indirectly obtain WLAN-based Internet connectivity) with a WLAN STA 152 connected to a WLAN AP 150. 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 as described above with respect to the sidelinks 162, 166, and 168.

[0062] 2A illustrates an exemplary wireless network structure 200. For example, the 5GC 210 (also referred to as Next Generation Core (NGC)) may be functionally viewed as control plane (C-plane) functions 214 (e.g., UE registration, authentication, network access, gateway selection, etc.) and user plane (U-plane) functions 212 (e.g., UE gateway functions, access to data networks, IP routing, etc.) that operate cooperatively to form a core network. A user plane interface (NG-U) 213 and a control plane interface (NG-C) 215 connect the gNB 222 to the 5GC 210, specifically to the user plane function 212 and the control plane function 214, respectively. In an additional configuration, the 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 one or more gNBs 222, while other configurations include one or more of both the ng-eNB 224 and the gNB 222. Either the gNB 222 or the ng-eNB 224 (or both) may communicate with one or more UEs 204 (e.g., any of the UEs described herein).

[0063] Another optional aspect may include a location server 230, which may be in communication with the 5GC 210 to provide location assistance to the UE(s) 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 across multiple physical servers, etc.), or alternatively, each may correspond to a single server. The location servers 230 may be configured to support one or more location services for UEs 204 that may connect to the location server 230 via the core network, the 5GC 210, and / or via the Internet (not shown). Furthermore, the location server 230 may be integrated into components of the core network, or alternatively, may be external to the core network (e.g., a third-party server, such as an original equipment manufacturer (OEM) server or a service server).

[0064] 2B illustrates another exemplary wireless network structure 240. The 5GC 260 (which may correspond to the 5GC 210 of FIG. 2A) may be considered functionally as control plane functions provided by an access and mobility management function (AMF) 264 and user plane functions provided by a user plane function (UPF) 262, which operate cooperatively to form a core network (i.e., the 5GC 260). The functions of the AMF 264 include registration management, connection management, reachability management, mobility management, lawful interception, transport for session management (SM) messages between one or more UEs 204 (e.g., any of the UEs described herein) and a session management function (SMF) 266, transparent proxy services for routing SM messages, access authentication and access authorization, transport for short message service (SMS) messages between the UE 204 and a short message service function (SMSF) (not shown), and security anchor functionality (SEAF). The AMF 264 also interacts with an authentication server function (AUSF) (not shown) and the UE 204 to receive intermediate keys established as a result of the UE 204 authentication process. In case of universal mobile telecommunications system (UMTS) subscriber identity module (USIM) based authentication, the AMF 264 retrieves security material from the AUSF. The AMF 264 functionality also includes 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 Location Management Function (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 functions for non-3GPP (Third Generation Partnership Project) access networks.

[0065] The functions of the UPF 262 include acting as an anchor point for intra / inter-RAT mobility (when applicable), acting as an external protocol data unit (PDU) session point for interconnection to a data network (not shown), routing and forwarding of 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) handling 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 forwarding of location service messages on the user plane between the UE 204 and a location server such as the SLP 272.

[0066] 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, some control of policy enforcement and QoS, and downlink data notification. The interface through which the SMF 266 communicates with the AMF 264 is called the N11 interface.

[0067] 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 across multiple physical servers, etc.), or alternatively, each may represent a single server. The LMF 270 may be configured to support one or more location services for UEs 204 that may connect to the LMF 270 via a core network, the 5GC 260, and / or via the Internet (not shown). The SLP 272 may support similar functions as the LMF 270, except that the LMF 270 may communicate with the AMF 264, the NG-RAN 220, and the UE 204 via a control plane (e.g., using interfaces and protocols intended to carry signaling messages rather than voice or data), and the SLP 272 may communicate with the UE 204 and external clients (e.g., third-party servers 274) via a user plane (e.g., using protocols intended to carry voice and / or data, such as transmission control protocol (TCP) and / or IP).

[0068] Yet another optional aspect may include a third party server 274, which may be in communication with the LMF 270, the SLP 272, the 5GC 260 (e.g., via the AMF 264 and / or the UPF 262), the NG-RAN 220, and / or the UE 204 to obtain location information (e.g., a location estimate) for the UE 204. Thus, in some cases, the third party server 274 may be referred to as a location services (LCS) client or an external client. The third party servers 274 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.

[0069] The user plane interface 263 and the control plane interface 265 connect the 5GC 260, specifically the UPF 262 and the AMF 264, respectively, to one or more gNBs 222 and / or ng-eNBs 224 in the NG-RAN 220. The interface between the gNB(s) 222 and / or ng-eNB(s) 224 and the AMF 264 is referred to as the “N2” interface, and the interface between the gNB(s) 222 and / or ng-eNB(s) 224 and the UPF 262 is referred to as the “N3” interface. The gNB(s) 222 and / or ng-eNB(s) 224 of the NG-RAN 220 may communicate directly with each other via a backhaul connection 223 referred to as the “Xn-C” interface. One or more of the gNBs 222 and / or ng-eNBs 224 may communicate with one or more UEs 204 via a wireless interface referred to as a “Uu” interface.

[0070] The functionality of the gNB 222 may be divided between a gNB Central Unit (gNB-CU) 226, one or more gNB Distributed Units (gNB-DUs) 228, and one or more gNB Radio Units (gNB-RUs) 229. The gNB-CU 226 is a logical node that includes base station functions such as forwarding user data, mobility control, radio access network sharing, positioning, session management, etc., except for those functions exclusively allocated to the gNB-DU(s) 228. More specifically, the gNB-CU 226 typically hosts the Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP) protocols of the gNB 222. The gNB-DU 228 is a logical node that typically hosts the Radio Link Control (RLC), Medium Access Control (MAC) layers of the gNB 222. Its operation is controlled by the gNB-CU 226. One gNB-DU 228 can support one or multiple cells, and one cell is supported by only one gNB-DU 228. The interface 232 between the gNB-CU 226 and one or more gNB-DUs 228 is referred to as the "F1" interface. The physical (PHY) layer functionality of the gNB 222 is generally hosted by one or more standalone gNB-RUs 229, which perform functions such as power amplification and signal transmission / reception. The interface between the gNB-DU 228 and the gNB-RU 229 is referred to as the "Fx" interface. Thus, the UE 204 communicates with the gNB-CU 226 via the RRC, SDAP, and PDCP layers, with the gNB-DU 228 via the RLC and MAC layers, and with the gNB-RU 229 via the PHY layer.

[0071] The deployment of a communication system such as a 5G NR system can be configured in multiple ways with various components or components. In a 5G NR system or network, network equipment such as a network node, network entity, mobility element of the network, RAN node, core network node, network element, or base station, or one or more units (or one or more components) performing base station functionality, can be implemented in an aggregated or separated architecture. For example, a base station (such as a Node B (NB), evolved NB (eNB), NR base station, 5G NB, access point (AP), transmit receive point (TRP), or cell) can be implemented as an aggregated base station (also known as a standalone base station or monolithic base station) or a separated base station.

[0072] An aggregated base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A separated base station may be configured to utilize a protocol stack that is physically or logically distributed among two or more units, such as one or more centralized or centralized units (CUs), one or more distributed units (DUs), or one or more radio units (RUs). In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU or alternatively distributed geographically or virtually across one or more other RAN nodes. A DU may be implemented to communicate with one or more RUs. Each of the CU, DU, and RU may also be implemented as a virtual unit, i.e., a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0073] The operation of a base station type or network design may take into account the aggregated nature of the base station functions. For example, a separated base station may be utilized in an integrated access backhaul (IAB) network, an open radio access network (O-RAN, such as a network configuration supported by the O-RAN alliance), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Disaggregation may include distributing functions across two or more units in different physical locations, as well as distributing functions virtually for at least one unit, which may allow flexibility in network design. Various units of a separated base station, or a separated RAN architecture, may be configured for wired or wireless communication with at least one other unit.

[0074] 2C illustrates an exemplary split base station architecture according to an aspect of the disclosure. The split base station architecture 250 may include one or more central units (CUs) 280 (e.g., gNB-CU 226) that may communicate directly with a core network 267 (e.g., 5GC 210, 5GC 260) via a backhaul link or indirectly with the core network 267 through one or more split base station units (e.g., a near real-time (near RT) RAN intelligent controller (RIC) 259 via an E2 link, or a non-real-time (non-RT) RIC 257 associated with a Service Management and Orchestration (SMO) framework 255, or both). The CU 280 may communicate with one or more distributed units (DUs) 285 (e.g., gNB-DU 228) via respective midhaul links, such as an F1 interface. The DU 285 may communicate with one or more radio units (RUs) 287 (e.g., gNB-RU 229) via respective fronthaul links. The RUs 287 may communicate with respective UEs 204 via one or more radio frequency (RF) access links. In some implementations, a UE 204 may be served by multiple RUs 287 simultaneously.

[0075] Each of the units, i.e., CU 280, DU 285, RU 287, quasi-RT RIC 259, non-RT RIC 257, and SMO framework 255, may include or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) over a wired or wireless transmission medium. Each of the units, or an associated processor or controller that provides instructions to the unit's communication interface, may be configured to communicate with one or more of the other units over a transmission medium. For example, the units may include a wired interface configured to receive or transmit signals to one or more of the other units over a wired transmission medium. Furthermore, the units may include a wireless interface, which may include a receiver, transmitter, or transceiver (such as a radio frequency (RF) transceiver) configured to receive or transmit or transmit signals over a wireless transmission medium to one or more of the other units.

[0076] In some aspects, the CU280 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented with an interface configured to communicate signals with other control functions hosted by the CU280. The CU280 may be configured to handle user plane functions (i.e., central unit-user plane (CU-User Plane, CU-UP)), control plane functions (i.e., central unit-control plane (CU-Control Plane, CU-CP)), or a combination thereof. In some implementations, the CU280 may be logically divided into one or more CU-UP units and one or more CU-CP units. The CU-UP unit, when implemented in an O-RAN configuration, may communicate bidirectionally with the CU-CP unit via an interface, such as an E1 interface. The CU 280 may be implemented to communicate with the DU 285, as necessary, for network control and signaling.

[0077] The DU 285 may correspond to a logical unit including one or more base station functions for controlling the operation of one or more RUs 287. In some aspects, the DU 285 may host one or more of a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and one or more upper physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.), at least in part according to a functional division such as that defined by the 3rd Generation Partnership Project (3GPP). In some aspects, the DU 285 may further host one or more lower PHY layers. Each layer (or module) may be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 285 or with a control function hosted by the CU 280.

[0078] The lower layer functions may be implemented by one or more RUs 287. In some deployments, the RUs 287 controlled by the DUs 285 may correspond to logical nodes hosting RF processing functions, or lower PHY layer functions (such as performing fast Fourier transforms (FFTs), inverse FFTs (iFFTs), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc.), or both, based at least in part on a functional division such as a lower layer functional division. In such an architecture, the RU(s) 287 may be implemented to handle over the air (OTA) communications with one or more UEs 204. In some implementations, real-time and non-real-time aspects of control plane and user plane communications with the RU(s) 287 may be controlled by the corresponding DUs 285. In some scenarios, this configuration may enable the DU(s) 285 and the CU 280 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

[0079] The SMO framework 255 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO framework 255 may be configured to support deployment of dedicated physical resources for RAN coverage requirements that may be managed via an operation and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO framework 255 may be configured to interact with a cloud computing platform (such as an open cloud (O-cloud) 269) to perform network element lifecycle management (such as instantiating virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, the CU 280, the DU 285, the RU 287, and the quasi-RT RIC 259. In some implementations, the SMO framework 255 may communicate with hardware aspects of a 4G RAN, such as an open eNB (O-eNB) 261, via an O1 interface. Additionally, in some implementations, the SMO framework 255 can communicate directly with one or more RUs 287 via an O1 interface. The SMO framework 255 may also include a non-RT RIC 257 configured to support the functionality of the SMO framework 255.

[0080] The non-RT RIC 257 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, Artificial Intelligence / Machine Learning (AI / ML) workflows including model training and updates, or policy-based guidance of applications / features in the quasi-RT RIC 259. The non-RT RIC 257 may be coupled to or in communication with the quasi-RT RIC 259 (e.g., via an A1 interface). The quasi-RT RIC 259 may be configured to include logic functions that enable near real-time control and optimization of RAN elements and resources by data collection and action over interfaces (e.g., via an E2 interface) that connect one or more CUs 280, one or more DUs 285, or both, and the O-eNB to the quasi-RT RIC 259.

[0081] In some implementations, the non-RT RIC 257 may receive parameters or external enrichment information from an external server to generate an AI / ML model to be deployed to the quasi-RT RIC 259. Such information may be utilized by the quasi-RT RIC 259 or may be received from a non-network data source or from a network function in the SMO framework 255 or the non-RT RIC 257. In some embodiments, the non-RT RIC 257 or the quasi-RT RIC 259 may be configured to adjust RAN behavior or performance. For example, the non-RT RIC 257 may employ the AI / ML model to monitor long-term trends and patterns in performance and implement corrective actions through the SMO framework 255 (e.g., reconfiguration via O1) or through the creation of RAN management policies (e.g., A1 policies).

[0082] 3A, 3B, and 3C illustrate several example components (represented by corresponding blocks) that may be incorporated in a UE 302 (which may correspond to any of the UEs described herein), a base station 304 (which may correspond to any of the base stations described herein), and a network entity 306 (which may correspond to or embody any of the network functions described herein, including a location server 230 and an LMF 270, or alternatively may be independent of the NG-RAN 220 and / or 5GC 210 / 260 infrastructure shown in FIGS. 2A and 2B, such as a private network) to support the operations described herein. It will be understood 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 in other devices in a communication system. For example, other devices in the system may include components similar to the described components to provide similar functionality. Also, a given device may include one or more of the components. For example, a device may contain multiple transceiver components that enable the device to operate on multiple carriers and / or communicate via different technologies.

[0083] The UE 302 and base station 304 each include one or more wireless wide area network (WWAN) transceivers 310 and 350, respectively, providing means for communicating (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for refraining from transmitting, etc.) over one or more wireless communications networks (not shown), such as an NR network, an LTE network, a GSM network, etc. The WWAN transceivers 310 and 350 may each be connected to one or more antennas 316 and 356, respectively, for communicating with other network nodes, such as other UEs, access points, base stations (e.g., eNBs, gNBs), etc., over 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 in a particular frequency spectrum). The WWAN transceivers 310 and 350 may be variously configured for transmitting and encoding signals 318 and 358, respectively (e.g., messages, instructions, information, etc.), and conversely, for receiving and decoding signals 318 and 358, respectively (e.g., messages, instructions, information, pilots, etc.), in accordance with a designated RAT. Specifically, the WWAN transceivers 310 and 350 include one or more transmitters 314 and 354, respectively, for transmitting and encoding signals 318 and 358, respectively, and include one or more receivers 312 and 352, respectively, for receiving and decoding signals 318 and 358, respectively.

[0084] The UE 302 and base station 304 also each, at least in some cases, include one or more short-range wireless transceivers 320 and 360, respectively. The short-range wireless transceivers 320 and 360 may be connected to one or more antennas 326 and 366, respectively, and 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 communication (NFC), etc.) over the wireless communication medium. The short-range wireless transceivers 320 and 360 may be variously configured for transmitting and encoding signals 328 and 368, respectively (e.g., messages, instructions, information, etc.), and conversely, for receiving and decoding signals 328 and 368, respectively (e.g., messages, instructions, information, pilots, etc.), in accordance with a specified RAT. Specifically, the short-range wireless transceivers 320 and 360 include one or more transmitters 324 and 364, respectively, for transmitting and encoding signals 328 and 368, respectively, and include one or more receivers 322 and 362, respectively, for receiving and decoding signals 328 and 368, respectively. As specific examples, the short-range wireless transceivers 320 and 360 may be WiFi transceivers, Bluetooth® transceivers, Zigbee® and / or Z-Wave® transceivers, NFC transceivers, or vehicle-to-vehicle (V2V) and / or vehicle-to-everything (V2X) transceivers.

[0085] The UE 302 and the base station 304 also, at least in some cases, include satellite signal receivers 330 and 370. The satellite signal receivers 330 and 370 may be connected to one or more antennas 336 and 376, respectively, and may provide a means for receiving and / or measuring satellite positioning / communication signals 338 and 378, respectively. If the satellite signal receivers 330 and 370 are satellite positioning system receivers, the satellite positioning / communication signals 338 and 378 may be Global Positioning System (GPS) signals, Global Navigation Satellite System (GLONASS) signals, Galileo signals, Beidou signals, Navigation Satellite System of India (NAVIC), Quasi-Zenith Satellite System (QZSS), etc. If the satellite signal receivers 330 and 370 are non-terrestrial network (NTN) receivers, the satellite positioning / communication signals 338 and 378 may be communication signals (e.g., carrying control and / or user data) originating from a 5G network. Satellite signal receivers 330 and 370 may comprise any suitable hardware and / or software for receiving and processing satellite positioning / communications signals 338 and 378, respectively. Satellite signal receivers 330 and 370 may request information and action from other systems as appropriate and, at least in some cases, perform calculations using the acquired measurements to determine the locations of UE 302 and base station 304, respectively, according to any suitable satellite positioning system algorithms.

[0086] The base station 304 and the network entity 306 each include one or more network transceivers 380 and 390, respectively, that provide a means for communicating (e.g., a means for transmitting, a means for receiving, etc.) with other network entities (e.g., other base stations 304, other network entities 306). For example, the base station 304 may employ one or more network transceivers 380 to communicate with other base stations 304 or network entities 306 over one or more wired or wireless backhaul links. As another example, the network entity 306 may employ one or more network transceivers 390 to communicate with one or more base stations 304 over one or more wired or wireless backhaul links or with other network entities 306 over one or more wired or wireless core network interfaces.

[0087] The transceiver may be configured to communicate over a wired link or a wireless link. The transceiver (whether a wired transceiver or a wireless transceiver) includes transmitter circuitry (e.g., transmitters 314, 324, 354, 364) and receiver circuitry (e.g., receivers 312, 322, 352, 362). The transceiver may be an integrated device (e.g., embodying transmitter and receiver circuitry in a single device) in some implementations, may comprise separate transmitter circuitry and separate receiver circuitry in some implementations, or may be embodied in other ways in other implementations. The transmitter and receiver circuitry of a wired transceiver (e.g., network transceivers 380 and 390 in some implementations) may be coupled to one or more wired network interface ports. The wireless transmitter circuitry (e.g., transmitters 314, 324, 354, 364) may include or be coupled to multiple antennas (e.g., antennas 316, 326, 356, 366), such as an antenna array that enables the respective device (e.g., UE 302, base station 304) to perform transmit "beamforming," as described herein. Similarly, the wireless receiver circuitry (e.g., receivers 312, 322, 352, 362) may include or be coupled to multiple antennas (e.g., antennas 316, 326, 356, 366), such as an antenna array that enables the respective device (e.g., UE 302, base station 304) to perform receive beamforming, as described herein. In one aspect, the transmitter circuitry and the receiver circuitry may share multiple identical antennas (e.g., antennas 316, 326, 356, 366), such that the respective device can only receive or transmit at a given time, but not both at the same time. The wireless transceivers (eg, WWAN transceivers 310 and 350, short range wireless transceivers 320 and 360) may also include network listen modules (NLMs) and the like for performing various measurements.

[0088] As used herein, various wireless transceivers (e.g., transceivers 310, 320, 350, and 360, and network transceivers 380 and 390, in some implementations) and wired transceivers (e.g., network transceivers 380 and 390, in some implementations) may be generally characterized as a "transceiver," "at least one transceiver," or "one or more transceivers." Thus, whether a particular transceiver is a wired or wireless transceiver may be inferred from the type of communication being implemented. For example, backhaul communications between network devices or servers generally involve signaling via wired transceivers, while wireless communications between a UE (e.g., UE 302) and a base station (e.g., base station 304) generally involve signaling via wireless transceivers.

[0089] The UE 302, base station 304, and network entity 306 also include other components that may be used in conjunction with operations as disclosed herein. The UE 302, base station 304, and network entity 306 each include one or more processors 332, 384, and 394, for example, to provide functionality related to wireless communications and to provide other processing functionality. Thus, the processors 332, 384, and 394 may comprise processing means, such as determining means, calculating means, receiving means, transmitting means, and directing means. In one aspect, the processors 332, 384, and 394 may include, for example, one or more general-purpose processors, multi-core processors, central processing units (CPUs), ASICs, digital signal processors (DSPs), field programmable gate arrays (FPGAs), other programmable logic devices or processing circuits, or various combinations thereof.

[0090] The UE 302, base station 304, and network entity 306 include memory circuitry implementing memories 340, 386, and 396, respectively (e.g., each including a memory device) for maintaining information (e.g., information indicating reserved resources, thresholds, parameters, etc.). Thus, the memories 340, 386, and 396 may comprise means for storing, means for retrieving, means for maintaining, etc. In some cases, the UE 302, base station 304, and network entity 306 may include positioning components 342, 388, and 398, respectively. The positioning components 342, 388, and 398 may be hardware circuits that are part of or coupled to the processors 332, 384, and 394, respectively, that, when executed, cause the UE 302, base station 304, and network entity 306 to perform the functions described herein. In other aspects, the positioning components 342, 388, and 398 may be external to the processors 332, 384, and 394 (e.g., part of a modem processing system, integrated with another processing system, etc.). Alternatively, the positioning components 342, 388, and 398 may be memory modules stored in the memories 340, 386, and 396, respectively, that when executed by the processors 332, 384, and 394 (or a modem processing system, another processing system, etc.), cause the UE 302, the base station 304, and the network entity 306 to perform the functions described herein. FIG. 3A illustrates possible locations of the positioning component 342, which may be part of, for example, one or more WWAN transceivers 310, the memory 340, the one or more processors 332, or any combination thereof, or may be a stand-alone component. FIG. 3B shows possible locations of a positioning component 388, which may be, for example, part of one or more WWAN transceivers 350, memory 386, one or more processors 384, or any combination thereof, or may be a stand-alone component.FIG. 3C illustrates possible locations of a positioning component 398, which may be, for example, part of one or more network transceivers 390, memory 396, one or more processors 394, or any combination thereof, or may be a stand-alone component.

[0091] The UE 302 may include one or more sensors 344 coupled to the one or more processors 332 to provide a means of sensing or detecting movement and / or orientation information that is independent of movement data derived from signals received by the one or more WWAN transceivers 310, the one or more short-range wireless transceivers 320, and / or the satellite signal receiver 330. By way of example, the sensor(s) 344 may include an accelerometer (e.g., a micro-electrical mechanical systems (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometric altimeter), and / or any other type of movement detection sensor. Additionally, the sensor(s) 344 may include multiple different types of devices and combine their outputs to provide movement information. For example, the sensor(s) 344 may use a combination of a multi-axis accelerometer and an orientation sensor to provide the ability to calculate position in a two-dimensional (2D) and / or three-dimensional (3D) coordinate system.

[0092] Additionally, the UE 302 includes a user interface 346 that provides a means for providing indications to a user (e.g., audio and / or visual indications) 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 304 and the network entity 306 may also include user interfaces.

[0093] Referring more particularly to the one or more processors 384, on the downlink, IP packets from the network entity 306 may be provided to the processor 384. The one or more processors 384 may implement functionality for an RRC layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, and a Medium Access Control (MAC) layer. The one or more processors 384 may provide RRC layer functions associated with broadcasting system information (e.g., master information blocks (MIBs), system information blocks (SIBs)), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-RAT mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with forwarding of higher layer PDUs, error correction with 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 functions associated with mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization.

[0094] The transmitter 354 and receiver 352 may implement Layer-1 (L1) functions associated with various signal processing functions. Layer-1, including the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) coding / decoding of the transport channel, interleaving, rate matching, mapping onto the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The transmitter 354 handles mapping onto signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to orthogonal frequency division multiplexing (OFDM) subcarriers, multiplexed with a reference signal (e.g., pilot) in the time and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain OFDM symbol stream. The OFDM symbol streams are spatially precoded to generate multiple spatial streams. Channel estimates from a channel estimator may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimates may be derived from a reference signal and / or channel condition feedback transmitted by the UE 302. Each spatial stream may then be provided to one or more different antennas 356. The transmitter 354 may modulate an RF carrier with the individual spatial streams for transmission.

[0095] At the UE 302, the receiver 312 receives signals through its respective antenna(s) 316. The receiver 312 recovers the information modulated onto the RF carriers and provides the information to one or more processors 332. The transmitter 314 and the receiver 312 perform layer 1 functions associated with various signal processing functions. The receiver 312 may perform spatial processing on the information to recover any spatial streams destined for the UE 302. If multiple spatial streams are destined for the UE 302, they may be combined by the receiver 312 into a single OFDM symbol stream. The receiver 312 then converts the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal includes 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 most likely signal constellation points transmitted by the base station 304. 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 304. The data and control signals are then provided to one or more processors 332 that implement Layer 3 (L3) and Layer 2 (L2) functions.

[0096] In the uplink, one or more processors 332 provide demultiplexing between transport and logical channels, packet reassembly, decryption, header recovery, and control signal processing to recover IP packets from the core network. The one or more processors 332 are also responsible for error detection.

[0097] Similar to the functionality described in connection with downlink transmissions by the base station 304, the one or more processors 332 provide RRC layer functionality related to system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with forwarding 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 associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via hybrid automatic repeat request (HARQ), priority handling, and logical channel prioritization.

[0098] Channel estimates derived by the channel estimator from a reference signal or feedback transmitted by the base station 304 may be used by the transmitter 314 to select an appropriate coding and modulation scheme and to facilitate spatial processing. The spatial streams generated by the transmitter 314 may be provided to different antenna(s) 316. The transmitter 314 may modulate an RF carrier with the individual spatial streams for transmission.

[0099] Uplink transmissions are processed at the base station 304 in a manner similar to that described with respect to the receiver function at the UE 302. The receiver 352 receives signals via its respective antenna(s) 356. The receiver 352 recovers information modulated onto an RF carrier and provides the information to one or more processors 384.

[0100] In the uplink, the one or more processors 384 provide demultiplexing between transport and logical channels, packet reassembly, decryption, header recovery, and control signal processing to recover IP packets from the UE 302. The IP packets from the one or more processors 384 may be provided to a core network. The one or more processors 384 are also responsible for error detection.

[0101] For convenience, the UE 302, base station 304, and / or network entity 306 are illustrated in Figures 3A, 3B, and 3C as including various components that may be configured according to various examples described herein. However, it will be understood that the illustrated components may have different functions in different designs. In particular, various components in Figures 3A-3C are optional in alternative configurations, and various aspects include configurations that may vary due to design choice, cost, device use, or other considerations. For example, in the case of Figure 3A, a particular implementation of the UE 302 may omit the WWAN transceiver(s) 310 (e.g., a wearable device or tablet computer or PC or laptop may have Wi-Fi and / or Bluetooth capabilities without cellular capabilities), or may omit the short-range wireless transceiver(s) 320 (e.g., cellular only, etc.), or may omit the satellite signal receiver 330, or may omit the sensor(s) 344, etc. 3B, a particular implementation of base station 304 may omit WWAN transceiver(s) 350 (e.g., a Wi-Fi “hotspot” access point without cellular capability), or may omit short-range wireless transceiver(s) 360 (e.g., cellular only), or may omit satellite receiver 370, etc. For brevity, examples of various alternative configurations are not provided herein, but should be readily apparent to one of ordinary skill in the art.

[0102] The various components of the UE 302, base station 304, and network entity 306 may be communicatively coupled to one another via data buses 334, 382, ​​and 392, respectively. In an aspect, the data buses 334, 382, ​​and 392 may form or be part of communication interfaces of the UE 302, base station 304, and network entity 306, respectively. For example, when different logical entities are embodied within the same device (e.g., gNB and location server functionality integrated within the same base station 304), the data buses 334, 382, ​​and 392 may provide communication between them.

[0103] The components of Figures 3A, 3B, and 3C may be implemented in a variety of ways. In some implementations, the components of Figures 3A, 3B, and 3C may be implemented in one or more circuits, such as, for example, one or more processors and / or one or more ASICs (which may include one or more processors), 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 this functionality. For example, some or all of the functionality represented by blocks 310-346 may be implemented by the processor and memory component(s) of the UE 302 (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 350-388 may be implemented by the processor and memory component(s) of the base station 304 (e.g., by execution of appropriate code and / or by appropriate configuration of the processor components). Also, some or all of the functionality represented by blocks 390-398 may be implemented by the processor and memory component(s) of the network entity 306 (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 of the UE 302, base station 304, network entity 306, etc., such as the processors 332, 384, 394, transceivers 310, 320, 350, and 360, memories 340, 386, and 396, positioning components 342, 388, and 398, etc.

[0104] In some designs, the network entity 306 may be implemented as a core network component. In other designs, the network entity 306 may be separate from the network operator or operation of the cellular network infrastructure (e.g., the NG RAN 220 and / or the 5GC 210 / 260). For example, the network entity 306 may be a component of a private network that may be configured to communicate with the UE 302 via the base station 304 or independently of the base station 304 (e.g., via a non-cellular communication link such as WiFi).

[0105] FIG. 4 illustrates an example wireless communication system 400 in which a V-UE 404 is exchanging ranging signals with an RSU 410 and another V-UE 406 according to an aspect of the disclosure. As illustrated in FIG. 6, wideband (e.g., FR1) ranging signals (e.g., Zadoff Chu sequence) are transmitted by both endpoints (e.g., V-UE 404 and RSU 410, and V-UE 404 and V-UE 406). In an aspect, the ranging signals may be sidelink positioning reference signals (SL-PRS) transmitted by the participating V-UEs 404 and 406 on uplink resources. Upon receiving the ranging signal from a transmitter (e.g., V-UE 404), a receiver (e.g., RSU 410 and / or V-UE 406) responds by sending a ranging signal that includes a measurement of the difference between the reception time of the ranging signal and the transmission time of the response ranging signal, referred to as the receiver receive-transmit (Rx-Tx) time difference measurement.

[0106] Upon receiving the reply ranging signal, the transmitter (or other positioning entity) can calculate the RTT between the transmitter and the receiver based on the receiver's Rx-Tx time difference measurement and a measurement of the difference between the transmission time of the first ranging signal and the reception time of the reply ranging signal (referred to as the transmitter's transmit-receive (Tx-Rx) time difference measurement). The transmitter (or other positioning entity) uses the RTT and the speed of light to estimate the distance between the transmitter and the receiver. If one or both of the transmitter and the receiver are beamforming capable, it may also be possible to determine the angle between the V-UE 604 and the V-UE 606. Additionally, if the receiver provides its Global Positioning System (GPS) location in the reply ranging signal, the transmitter (or other positioning entity) may be able to determine the absolute location of the transmitter as opposed to the relative location of the transmitter with respect to the receiver.

[0107] As can be seen, the ranging accuracy improves with the bandwidth of the ranging signal. Specifically, a higher bandwidth can better separate different multipaths of the ranging signal.

[0108] Note that this positioning procedure assumes that the V-UEs involved are time synchronized (i.e., their system frame time is the same as the other V-UE(s) or has a known offset relative to the other V-UE(s). Furthermore, while Figure 4 shows two V-UEs, it will be appreciated that they do not have to be V-UEs, but instead may be any other type of UE capable of sidelink communication.

[0109] NR supports several cellular network-based positioning techniques, including downlink-based positioning methods, uplink-based positioning methods, and downlink- and uplink-based positioning methods. Downlink-based positioning methods include observed time difference of arrival (OTDOA) in LTE, downlink time difference of arrival (DL-TDOA) in NR, and downlink angle-of-departure (DL-AoD) in NR. FIG. 5 illustrates examples of various positioning methods according to aspects of the present disclosure. In an OTDOA or DL-TDOA positioning procedure illustrated by scenario 510, a UE measures the difference between times of arrival (ToAs) of reference signals (e.g., positioning reference signals (PRS)) received from pairs of base stations, called reference signal time difference (RSTD) measurements or time difference of arrival (TDOA) measurements, and reports them to a positioning entity. More specifically, the UE receives identifiers (IDs) of a reference base station (e.g., a serving base station) and multiple non-reference base stations in the assistance data. The UE then measures the RSTD between the reference base station and each of the non-reference base stations. Based on the known locations of the involved base stations and the RSTD measurements, a positioning entity (e.g., the UE in case of UE-based positioning or a location server in case of UE-assisted positioning) can estimate the location of the UE.

[0110] For DL-AoD positioning illustrated by scenario 520, the positioning entity uses measurement reports from the UE of received signal strength measurements of multiple downlink transmit beams to determine the angle(s) between the UE and the transmitting base station(s). The positioning entity can then estimate the location of the UE based on the determined angle(s) and the known location(s) of the transmitting base station.

[0111] Uplink-based positioning methods include uplink time difference of arrival (UL-TDOA) and uplink angle-of-arrival (UL-AoA). UL-TDOA is similar to DL-TDOA, but is based on an uplink reference signal (e.g., Sounding Reference Signal (SRS)) transmitted by the UE to multiple base stations. Specifically, the UE transmits one or more uplink reference signals that are measured by the reference base station and multiple non-reference base stations. Each base station then reports the time of reception of the reference signal (called the relative time of arrival (RTOA)) to a positioning entity (e.g., a location server), which knows the locations and relative timing of the participating base stations. Based on the reception-to-reception (Rx-Rx) time difference between the reported RTOA of the reference base station and that of each non-reference base station, the known locations of the base stations, and their known timing offsets, the positioning entity can estimate the location of the UE using TDOA.

[0112] For UL-AoA positioning, one or more base stations measure the received signal strength of one or more uplink reference signals (e.g., SRS) received from the UE on one or more uplink receive beams. The positioning entity uses the signal strength measurements and the angle(s) of the receive beam(s) to determine the angle(s) between the UE and the base station(s). Based on the determined angle(s) and the known location(s) of the base station(s), the positioning entity can then estimate the location of the UE.

[0113] Downlink and uplink based positioning methods include Extended Cell ID (E-CID) positioning, and Multiple Round Trip Time (RTT) positioning (also called "Multi-cell RTT" and "Multi-RTT"). In an RTT procedure, a first entity (e.g., a base station or a UE) transmits a first RTT-related signal (e.g., a PRS or an SRS) to a second entity (e.g., a UE or a base station), and the second entity transmits a second RTT-related signal (e.g., an SRS or a PRS) back to the first entity. Each entity measures the time difference between the time of arrival (ToA) of the received RTT-related signal and the transmission time of the transmitted RTT-related signal. This time difference is called the reception-to-transmission (Rx-Tx) time difference. The Rx-Tx time difference measurement may be made or adjusted to include only the time difference between the nearest slot boundaries for the received and transmitted signals. Both entities may then send their Rx-Tx time difference measurements to a location server (e.g., LMF 270), which calculates the round trip propagation time (i.e., RTT) between the two entities from the two Rx-Tx time difference measurements (e.g., as the sum of the two Rx-Tx time difference measurements). Alternatively, one entity may send its Rx-Tx time difference measurements to the other entity, which then calculates the RTT. The distance between the two entities may be determined from the RTT and a known signal speed (e.g., the speed of light). In the case of multi-RTT positioning illustrated by scenario 530, a first entity (e.g., a UE or a base station) performs an RTT positioning procedure with multiple second entities (e.g., multiple base stations or UEs) to enable the location of the first entity to be determined based on the distance to the second entity and the known location of the second entity (e.g., using multilateration). As illustrated by scenario 540, RTT and multi-RTT methods can be combined with other positioning techniques such as UL-AoA and DL-AoD to improve location accuracy.

[0114] The E-CID positioning method is based on Radio Resource Management (RRM) measurements. In E-CID, the UE reports the serving cell ID, timing advance (TA), and identities, estimated timing, and signal strength of detected neighboring base stations. The location of the UE is then estimated based on this information and the known locations of the base stations.

[0115] To assist the positioning operation, a location server (e.g., location server 230, LMF 270, SLP 272) may provide assistance data to the UE. For example, the assistance data may include an identifier of a base station (or a cell / TRP of a base station) from which to measure a reference signal, reference signal configuration parameters (e.g., the number of consecutive slots containing a PRS, the periodicity of consecutive slots containing a PRS, a muting sequence, a frequency hopping sequence, a reference signal identifier, a reference signal bandwidth, etc.), and / or other parameters applicable to a particular positioning method. Alternatively, the assistance data may be obtained directly from the base station itself (e.g., in periodically broadcasted overhead messages, etc.). In some cases, the UE may be able to detect neighboring network nodes itself without using the assistance data.

[0116] In the case of OTDOA or DL-TDOA positioning procedures, the assistance data may further include an expected RSTD value and an associated uncertainty around the expected RSTD, i.e., a search window. In some cases, the value range for the expected RSTD may be + / - 500 microseconds (μs). In some cases, the value range for the expected RSTD uncertainty may be + / - 32 μs when any of the resources used for positioning measurements are in FR1. In other cases, the value range for the expected RSTD uncertainty may be + / - 8 μs when all of the resources used for positioning measurements are in FR2.

[0117] A location estimate may be referred to by other names, such as a position estimate, location, position, position fix, fix, etc. A location estimate may be geodetic and comprise coordinates (e.g., latitude, longitude, and possibly altitude), or urban and comprise a street address, postal address, or some other linguistic description of the location. A location estimate may also be defined relative to some other known location, or defined absolutely (e.g., using latitude, longitude, and possibly altitude). A location estimate may include an expected error or uncertainty (e.g., by including an area or volume within which the location is expected to be contained with some specified or default level of confidence).

[0118] NR supports or enables various sidelink positioning techniques. FIG. 6A illustrates various scenarios of interest for sidelink-only or joint Uu and sidelink positioning according to aspects of the disclosure. In scenario 610, at least one peer UE with a known location can improve the Uu-based positioning (e.g., multi-cell round trip time (RTT), downlink time difference of arrival (DL-TDOA), etc.) of the target UE by providing an additional anchor (e.g., using sidelink RTT (SL-RTT)). In scenario 620, a low-end (e.g., reduced capacity, or "RedCap") target UE may obtain the assistance of a premium UE to determine its location, e.g., using a sidelink positioning and ranging procedure with the premium UE. Compared to a low-end UE, the premium UE may have more capabilities, such as more sensors, faster processors, more memory, more antenna elements, higher transmit power capabilities, access to additional frequency bands, or any combination thereof. In scenario 630, a relay UE (e.g., with a known location) participates in the positioning estimation of a remote UE without performing uplink positioning reference signal (PRS) transmission over the Uu interface. Scenario 840 illustrates joint positioning of multiple UEs. Specifically, in scenario 640, two UEs with unknown positions can be located together in non-line-of-sight (NLOS) conditions by utilizing constraints from nearby UEs.

[0119] 6B illustrates additional scenarios of interest for sidelink-only or joint Uu and sidelink positioning according to aspects of the disclosure. In scenario 650, UEs used for public safety (e.g., by police, firefighters, etc.) may perform peer-to-peer (P2P) positioning and ranging for public safety and other uses. For example, in scenario 650, the public safety UEs are out of coverage of the network and may use sidelink positioning techniques to determine locations or relative distances and relative positions between the public safety UEs. Similarly, scenario 660 illustrates multiple UEs that are out of coverage and use sidelink positioning techniques such as SL-RTT to determine locations or relative distances and relative positions.

[0120] Various frame structures may be used to support downlink and uplink transmissions between network nodes (e.g., base stations and UEs). Figure 7 is a diagram 700 illustrating example frame structures according to aspects of the disclosure. The frame structure may be a downlink or uplink frame structure. Other wireless communication technologies may have different frame structures and / or different channels.

[0121] LTE, and possibly NR, employs orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. However, unlike LTE, NR also has the option of using OFDM on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. Generally, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, or the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the subcarrier spacing may be 15 kilohertz (kHz), and the minimum resource allocation (resource block) may be 12 subcarriers (i.e., 180 kHz). Thus, the nominal fast Fourier transform (FFT) size may be equal to 128, 256, 512, 1024, or 2048 for a system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (i.e., 6 resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for a system bandwidth of 1.25, 2.5, 5, 10, or 20 MHz, respectively.

[0122] LTE supports a single numerology (subcarrier spacing (SCS), symbol length, etc.). In contrast, NR may support multiple numerologies (μ), e.g., subcarrier spacings of 15 kHz (μ=0), 30 kHz (μ=1), 60 kHz (μ=2), 120 kHz (μ=3), and 240 kHz (μ=4) or more may be available. At each subcarrier spacing, there are 14 symbols per slot. For a 15 kHz SCS (μ=0), there is one slot per subframe, i.e., 10 slots per frame, the slot duration is 1 millisecond (ms), the symbol duration is 66.7 microseconds (μs), and the maximum nominal system bandwidth (in MHz) with an FFT size of 4K is 50. For a 30 kHz SCS (μ=1), there are two slots per subframe, i.e., 20 slots per frame, the slot duration is 0.5 ms, the symbol duration is 33.3 μs, and the maximum nominal system bandwidth (in MHz) for a 4K FFT size is 100. For a 60 kHz SCS (μ=2), there are four slots per subframe, i.e., 40 slots per frame, the slot duration is 0.25 ms, the symbol duration is 16.7 μs, and the maximum nominal system bandwidth (in MHz) for a 4K FFT size is 200. For a 120 kHz SCS (μ=3), there are eight slots per subframe, i.e., 80 slots per frame, the slot duration is 0.125 ms, the symbol duration is 8.33 μs, and the maximum nominal system bandwidth (in MHz) for a 4K FFT size is 400. For a 240 kHz SCS (μ=4), there are 16 slots per subframe, i.e., 160 slots per frame, the slot duration is 0.0625 ms, the symbol duration is 4.17 μs, and the maximum nominal system bandwidth (in MHz) with an FFT size of 4K is 800.

[0123] In the example of Figure 7, a numerology of 15 kHz is used. Thus, in the time domain, a 10 ms frame is divided into 10 equally sized subframes of 1 ms each, with each subframe containing one time slot. In Figure 7, time is represented horizontally (on the X-axis), with time increasing from left to right, and frequency is represented vertically (on the Y-axis), with frequency increasing (or decreasing) from bottom to top.

[0124] A resource grid may be used to represent a time slot, with each time slot including one or more time-parallel resource blocks (RBs) (also called physical RBs (PRBs)) in the frequency domain. The resource grid is further divided into multiple resource elements (REs). An RE may correspond to one symbol length in the time domain and one subcarrier in the frequency domain. In the numerology of FIG. 7, in the case of a normal cyclic prefix, an RB may include 12 consecutive subcarriers in the frequency domain and 7 consecutive symbols in the time domain for a total of 84 REs. In the case of an extended cyclic prefix, an RB may include 12 consecutive subcarriers in the frequency domain and 6 consecutive symbols in the time domain to obtain a total of 72 REs. The number of bits carried by each RE depends on the modulation scheme.

[0125] Some of the REs may carry reference (pilot) signals (RS). The reference signals may include positioning reference signals (PRS), tracking reference signals (TRS), phase tracking reference signals (PTRS), cell-specific reference signals (CRS), channel state information reference signals (CSI-RS), demodulation reference signals (DMRS), primary synchronization signals (PSS), secondary synchronization signals (SSS), synchronization signal blocks (SSBs), sounding reference signals (SRS), etc., depending on whether the illustrated frame structure is used for uplink or downlink communications. Figure 7 shows example locations of REs carrying reference signals (labeled "R").

[0126] In addition to downlink-based, uplink-based, and downlink-and-uplink-based positioning methods, NR supports various sidelink positioning techniques. For example, link-level ranging signals can be used to estimate the distance between a pair of V-UEs or between a V-UE and a roadside unit (RSU), similar to the round-trip-time (RTT) positioning procedure.

[0127] Sidelink communication takes place within a transmit or receive resource pool. In the frequency domain, the smallest resource allocation unit is a subchannel (e.g., a set of contiguous PRBs in the frequency domain). In the time domain, the resource allocation is one slot apart. However, some slots are not available for the sidelink and some slots contain feedback resources. In addition, sidelink resources may be (pre-)configured to occupy fewer than 14 symbols of a slot.

[0128] Sidelink resources are configured in the Radio Resource Control (RRC) layer. The RRC configuration can be pre-configured (e.g., preloaded on the UE) or by configuration (e.g., from the serving base station).

[0129] NR sidelinks support Hybrid Automatic Repeat Request (HARQ) retransmissions. FIG. 8A is a diagram 900 of an example slot structure without feedback resources according to an aspect of the disclosure. In the example of FIG. 8A, time is represented horizontally and frequency is represented vertically. In the time domain, the length of each block is one Orthogonal Frequency Division Multiplexing (OFDM) symbol, and 14 symbols make up a slot. In the frequency domain, the height of each block is one subchannel. Currently, the (pre)configured subchannel size can be selected from a set of {10, 15, 20, 25, 50, 75, 100} physical resource blocks (PRBs).

[0130] For a sidelink slot, the first symbol is a repetition of the previous symbol and is used for automatic gain control (AGC) setting. This is indicated by vertical and horizontal hashing in Fig. 8A. As shown in Fig. 8A, for the sidelink, the Physical Sidelink Control Channel (PSCCH) and the Physical Sidelink Shared Channel (PSSCH) are transmitted in the same slot. Similar to the Physical Downlink Control Channel (PDCCH), the PSCCH carries control information regarding sidelink resource allocation and a description of the sidelink data to be transmitted to the UE. Similarly, similar to the Physical Downlink Shared Channel (PDSCH), the PSSCH carries user data for the UE. In the example of Fig. 8A, the PSCCH occupies half the bandwidth of the subchannel and only occupies three symbols. Finally, there is a gap symbol after the PSSCH.

[0131] 8B is a diagram 950 of an example slot structure with feedback resources according to an aspect of the disclosure. In the example of FIG. 8B, time is represented horizontally and frequency is represented vertically. In the time domain, the length of each block is one OFDM symbol, and 14 symbols make up a slot. In the frequency domain, the height of each block is one subchannel.

[0132] The slot structure shown in Figure 8B is similar to the slot structure shown in Figure 8A, except that the slot structure shown in Figure 8B includes feedback resources. Specifically, the last two symbols of the slot were dedicated to the physical sidelink feedback channel (PSFCH). The first PSFCH symbol is a repetition of the second PSFCH symbol for AGC configuration. In addition to the gap symbol after the PSSCH, there is a gap symbol after the two PSFCH symbols. Currently, the resources for the PSFCH may be configured with a periodicity selected from the set of {0, 1, 2, 4} slots.

[0133] Another aspect of sidelink positioning is the configuration of sidelink resource pools for positioning (RP-Ps). The 12 symbols between the first symbol (for AGC) and the last symbol (gap) of a sidelink slot in the time domain and the assigned subchannel(s) in the frequency domain form a resource pool for sidelink transmission and / or reception. RP-Ps may be configured within the resource pool specifically for positioning purposes. Each RP-P includes an offset, a periodicity, a number of consecutive symbols in a slot (e.g., only one symbol), and / or a bandwidth within a component carrier (or a bandwidth across multiple component carriers). Furthermore, each RP-P may be associated to a zone or a distance from a reference location.

[0134] A base station (or UE) can assign one or more resource configurations from an RP-P to another UE. Additionally or alternatively, a UE (e.g., a relay or remote UE) can request one or more RP-P configurations, which can include in the request one or more of: (1) its location information (or zone identifier), (2) periodicity, (3) bandwidth, (4) offset, (5) number of symbols, and (6) whether a configuration with "low interference" is required (which may be determined via an assigned quality of service (QoS) or priority).

[0135] The base station or UE may configure / assign rate-matching resources or RP-Ps for rate-matching and / or muting to the sidelink UE such that when there is a collision between the assigned resources and another resource pool containing data (PSSCH) and / or control (PSCCH), the sidelink UE is expected to rate-match, mute, and / or puncture data, DMRS, and / or CSI-RS in the conflicting resources. This allows orthogonalization between positioning and data transmission for increased coverage of PRS signals.

[0136] 9 is a diagram 900 illustrating an example of a resource pool for positioning in a sidelink resource pool according to an aspect of the disclosure. In the example of FIG. 9, time is represented horizontally and frequency is represented vertically. In the time domain, the length of each block is an Orthogonal Frequency Division Multiplexing (OFDM) symbol, and 14 symbols make up a slot. In the frequency domain, the height of each block is a subchannel.

[0137] In the example of Fig. 9, the entire slot (except the first and last symbols) may be the resource pool for sidelink transmission and / or reception. That is, any symbol other than the first and last may be assigned for transmission and / or reception. However, the RP-P for sidelink transmission / reception is assigned to the last four pre-gap symbols of the slot. Therefore, non-sidelink positioning data such as user data, CSI-RS, and control information may only be transmitted in the first eight post-AGC symbols and not in the last four pre-gap symbols to prevent collision with the configured RP-P. Non-sidelink positioning data that would otherwise be transmitted in the last four pre-gap symbols may be punctured or muted, or non-sidelink data that would normally span more than eight post-AGC symbols may be rate-matched to fit into the eight post-AGC symbols.

[0138] Sidelink positioning reference signals (SL-PRS) have been defined to enable sidelink positioning procedures between UEs. SL-PRS resources, similar to downlink PRS (DL-PRS), consist of one or more resource elements (i.e., one OFDM symbol in the time domain, one subcarrier in the frequency domain). SL-PRS resources have been designed with comb-based patterns to enable Fast Fourier Transform (FFT)-based processing at the receiver. SL-PRS resources consist of non-staggered or only partially staggered resource elements in the frequency domain to give small time of arrival (TOA) uncertainties and reduced overhead for each SL-PRS resource. SL-PRS may also be associated with a specific RP-P (e.g., several SL-PRS may be allocated in several RP-Ps). SL-PRS have also been defined with intra-slot repetition (not shown in FIG. 9) to enable combining gains (if necessary). There may also be inter-UE coordination of RP-P to provide dynamic SL-PRS and data multiplexing while minimizing SL-PRS collisions.

[0139] FIG. 10 illustrates a resource pool for different positioning (RP-P) allocation procedure according to an aspect of the present disclosure. Specifically, FIG. 1000 illustrates a reservation-based approach between two relay UEs to minimize overhead / collisions caused by their associated target UEs that used the same RP-P. FIG. 1050 illustrates a two-step allocation procedure with a serving base station. In the first stage, the base station can allocate orthogonal RP-Ps. In the second stage, each relay UE determines which resources in the allocated RP-P should be allocated to the target UE.

[0140] There are two types of resource allocation for sidelink communication, called "Mode 1" and "Mode 2". For Mode 1 resource allocation, the base station assigns resources for sidelink communication between UEs. For Mode 2 resource allocation, the involved UEs autonomously select the sidelink resources. A congestion control mechanism is applied in NR-V2X for Mode 2 resource allocation and is similar to that in LTE-V2X. The UE may use two types of measurements to detect and mitigate the effects of congestion when Mode 2 resource allocation is applied: channel busy ratio (CBR) and channel occupancy ratio (CR). The CBR is calculated in each subframe as a fraction of busy resources in the resource pool in the last 100 milliseconds (ms). A resource (e.g., a set of resource elements, one or more symbols, one or more slots, etc.) is considered busy if the received energy level in the resource is higher than a given threshold. The CBR measurement result reflects the congestion on the medium. CR reflects the occupancy of resources by a UE: CR is the number of subchannels that a UE occupies in a 1000 ms time window.

[0141] With further reference to congestion control, packet priority is defined by higher layers and passed to the physical layer as shown in SCI-1. The CR and transmission parameters are adapted based on the relative priority of the UE's traffic and CBR. To react to fast fluctuations in resource congestion, NR-V2X defines a shorter interval for the calculation of CBR and CR. Currently, the interval is 1 or 2 ms in NR-V2X compared to 4 ms in LTE-V2X.

[0142] The NR sidelink supports CBR as a metric for congestion control. Sidelink received signal strength indication (RSSI) measurements are used for CBR estimation. Alternatively, RSRP measurements may be used. Congestion control can limit the following transmission parameters: (1) modulation and coding scheme (MCS) index and MCS table, (2) number of subchannels per transmission, (3) number of retransmissions, and (4) transmit power. For example, the more congestion on the medium, the lower the MCS and the lower the data rate. Similarly, the more congestion, the lower the transmit power to reduce interference. Absolute UE speed can also limit the transmission parameters.

[0143] FIG. 11 is a diagram 1100 illustrating an urban setting in which various UEs may be ON or actively transmitting sidelink SL-PRS and various other UEs may be OFF or not actively transmitting SL-PRS. For example, in a power saving mode or other setting, some UEs may not be transmitting SL-PRS despite being configured for sidelink communications. As shown, pedestrian UEs (e.g., vulnerable road users (VRUs)) may be ON and actively transmitting SL-PRS so that nearby UEs can measure the pedestrian UEs' SL-PRS. Various UE devices that are OFF and not actively transmitting SL-PRS signals may be configured for sidelink communications and may be receiving signals from nearby UEs that are ON and actively transmitting SL-PRS. Thus, UEs may be powered up and not actively transmitting some sidelink communications (e.g., SL-PRS reception and / or transmission is disabled) based on the UEs' configuration.

[0144] As mentioned, a vulnerable road user (VRU) may be an NR UE for vehicle-to-VRU or VRU-to-vehicle communications. For example, a hearing impaired person may receive a vibration from a wearable (VRU) when a vehicle is approaching based on a signal from the vehicle. Similarly, the wearable may transmit its location to the vehicle, and such location may be used by its driving assistance functions. In some circumstances, the UE may be configured to turn off, disable, or disconnect transmission and / or reception capabilities for sidelink communications. For example, the decision to wake up or "sleep" may be based on the discontinuous reception (DRX) period of the UE. These DRX periods are described in more detail below with respect to Figures 12A-C.

[0145] A UE may have configurations for sleep, wake-up, activation, deactivation, or discontinuous operation of transmission (Tx) or reception (Rx) of sidelink position reference signals (SL-PRS). Aspects of the present disclosure contemplate localized activation of these modes or configurations based on location data, network priority status, requests from other UEs, and UE priority. Because these and other features may reduce the UE's reliability for providing SL-PRS and may waste sidelink resources in the resource pool, various processes are disclosed below that may make the reduced reliability or puncturability of SL-PRS for a UE more predictable. That is, based on information shared between devices, assistance data, and previous history of transmissions, a UE may predict when and where another UE will deactivate one or more SL-PRS features. For example, various settings or configurations of the UE, specifically Tx / Rx capabilities, may provide at least a partial override of the UE's DRX mode. In short, a balance may be achieved between power savings via DRX mode and location monitoring / transmission via SL-PRS.

[0146] The UE is expected to monitor every downlink subframe on the Physical Downlink Control Channel (PDCCH) even when there is no traffic being sent from the network to the UE. This means that the UE must be "on" or active all the time, even when there is no traffic, because the UE does not know exactly when the network will be sending data for the UE. However, being active all the time is a significant power drain for the UE.

[0147] To address this issue, the UE may implement discontinuous reception (DRX) and / or connected mode discontinuous reception (CDRX) techniques. DRX and CDRX are mechanisms where the UE goes into a "sleep" mode during scheduled time periods and "wakes up" during other time periods. During the wake or active periods, the UE checks whether there is any data coming from the network, and if not, goes back to sleep mode.

[0148] To implement DRX and CDRX, the UE and the network need to be synchronized. In a worst case scenario, the network may try to send some data to the UE while the UE is in sleep mode, and the UE may wake up when there is no data to be received. To prevent such a scenario, the UE and the network should have a well-defined agreement on when the UE can be in sleep mode and when the UE should be awake / active. This agreement is standardized in various technical specifications. Note that unless otherwise specified, DRX includes CDRX, and therefore any reference to DRX refers to both DRX and CDRX.

[0149] The network (e.g., serving cell) can configure the UE with DRX / CDRX timing using the RRC Connection Reconfiguration message (for CDRX) or the RRC Connection Setup message (for DRX). The network can signal the following DRX configuration parameters to the UE: (1) DRX Period: duration of one "ON time" plus one "OFF time". This value is not explicitly specified in the RRC message, but rather is calculated by the subframe / slot time and the "Long DRX Period Start Offset". (2) ON Duration Timer: duration of the ON time in one DRX period. (3) DRX Inactivity Timer: how long the UE should stay "ON" after receiving a PDCCH (e.g., number of expected transmission instances). When this timer is ON, the UE stays in "ON state", which may extend the ON period to what would otherwise be an "OFF" period. (4) DRX retransmission timer: The maximum number of consecutive PDCCH subframes / slots that the UE should remain active for waiting for an incoming retransmission after the first available retransmission time. (5) Short DRX cycle: A DRX cycle that may be implemented within the "OFF" period of a long DRX cycle. (6) DRX short cycle timer: The consecutive number of subframes / slots that follow the short DRX cycle after the DRX inactivity timer expires.

[0150] 12A-12C illustrate example DRX configurations according to aspects of the disclosure. FIG. 12A illustrates an example DRX configuration 1200A in which a long DRX period (time from the start of one ON duration to the start of the next ON duration) is configured and PDCCH is not received during that period. FIG. 12B illustrates an example DRX configuration 1200B in which a long DRX period is configured and PDCCH is received during the ON duration 1210 of the illustrated second DRX period. Note that the ON duration 1210 ends at time 1212. However, the time that the UE is awake / active ("active time") is extended to time 1214 based on the length of the DRX inactivity timer and the time that the PDCCH is received. In particular, when the PDCCH is received, the UE starts the DRX inactivity timer and stays in the active state until expiration of that timer (which is reset every time a PDCCH is received during the active time).

[0151] Figure 12C illustrates an example DRX configuration 1200C in which a long DRX cycle is configured and a PDCCH and a DRX command MAC control element (MAC-CE) are received during the ON duration 1220 of the illustrated second DRX cycle. Note that the active time that begins during the ON duration 1220 would normally end at time 1224 due to the reception of a PDCCH at time 1222 and the subsequent expiration of a DRX inactivity timer at time 1224, as described above with reference to Figure 12B. However, in the example of Figure 12C, the active time is shortened to time 1226 based on the time at which a DRX command MAC-CE is received instructing the UE to end the DRX inactivity timer and the ON duration timer.

[0152] More specifically, the active time of a DRX cycle is the time during which the UE is considered to be monitoring the PDCCH. The active time may include the time during which the ON duration timer is running, the time during which the DRX inactivity timer is running, the time during which the DRX retransmission timer is running, the time during which the MAC contention resolution timer is running, the time during which a scheduling request is sent on the PUCCH and is pending, the time during which an uplink grant for a pending HARQ retransmission can occur and there is data in the corresponding HARQ buffer, or the time during which a PDCCH indicating a new transmission addressed to the UE's Cell Radio Network Temporary Identifier (C-RNTI) is not received after successful reception of a Random Access Response (RAR) for a preamble not selected by the UE. Also, in non-contention based random access, after receiving the RAR, the UE should be in the active state until a PDCCH indicating a new transmission addressed to the UE's C-RNTI is received.

[0153] According to one aspect of the disclosure, the DRX cycle may be configured based on other aspects of the UE's environment. That is, the duration of the active time, the period of inactivity required for sleep mode or OFF state, and the transition from a long DRX cycle to a short DRX cycle may be configured to depend on environmental and measured variables. For example, the UE may have location-based power saving features (e.g., DRX mode or state). A defined configuration for the DRX active time allows the UE's behavior to be more predictable with respect to its peers, as shown in FIG. 13.

[0154] The configuration or setting for determining when the UE's SL-PRS signal may be ON or OFF may be based on the device's location (e.g., indoors), the device's activity (e.g., moving, charging, etc.), remaining available power (e.g., power saving mode), distance from other UEs, operation mode (e.g., mode 1 or mode 2), or other settings. For example, a public safety UE may only be active when in an emergency location or outside a station boundary. As shown in FIG. 11, UEs that are not associated with a vulnerable situation (e.g., not a roadside pedestrian) have their SL-PRS signaling OFF. One or more regions or locations may be pre-configured or auto-configured in the UE such that the UE's SL-PRS transmission is switched to OFF mode in that location or region. Despite the UE's SL-PRS communication being OFF (e.g., Tx and Rx), the UE itself may be ON and may communicate to radio units (RUs) over an access link.

[0155] To save power or reduce interference, the UE may switch ON / OFF transmission and reception over a radio link with the radio unit. That is, the transmit (Tx) and receive (Rx) channels may be separately switchable ON / OFF such that the transmit channels to the radio unit are controlled independently from the receive channels. The DRX cycle or DRX mode may control the reception of a downlink control channel (e.g., PDCCH) from the radio unit. Similarly, the UE may switch ON / OFF transmission and reception of sidelink signals, in particular positioning reference signals (PRS). The aforementioned DRX cycle or DRX mode may be adapted to control the reception (Rx) of sidelink signals. This capability or extension of the DRX mode may be referred to as SL-DRX. With the SL-DRX feature, the UE may apply one or more of the DRX features described above with respect to Figures 12A-12C to the physical sidelink control channel (PSCCH) or the sidelink position reference signal (SL-PRS).

[0156] For example, in an active time or active state for SL-DRX, the UE may power up an antenna or receiver to receive (listen to) PSCCH and SL-PRS signals. In an inactive time or inactive state for SL-DRX, the UE may power down or switch off the antenna or receiver so that the UE cannot receive PSCCH or SL-PRS. When the UE switches off its sidelink receiver, the UE may be excluded from the resource pool or removed from assistance data (AD) that supports sidelink management. Similarly, when the SL-DRX function is in connected mode, there may be various sidelink capabilities remaining, but when the SL-DRX function is in idle mode, there may be few sidelink capabilities remaining. Thus, when a UE has SL-DRX capability, the network may not consider the UE to be an always-on resource or a reliable resource.

[0157] In DL-DRX OFF state, the UE may receive Positioning Reference Signals (PRS) from nearby UEs even though it does not monitor the PDCCH or other control channels. Based on the received PRS, the UE may keep or maintain a list of nearby UEs. When the UE's downlink is turned ON or reactivated, the UE may have accurate location information (e.g., from RTT) and may know the surrounding UEs for resource pool coordination. Similarly, in SL-DRX OFF state, an active UE (i.e., DL ON) may know nearby UEs and may receive or calculate location information based on RTT. This information about nearby UEs may be based on non-sidelink signals from the RU or network information. A PRS active UE may keep a list of nearby UEs and may also record their PRS status (ON / OFF). That is, DL-DRX and SL-DRX may have different DRX periods and may be activated / deactivated separately. This stored information related to nearby UEs, which may be received from the radio unit as assistance data or from UE-to-UE coordination, may enable the UEs to more quickly coordinate access to the resource pool upon wake-up. In Mode 1 or Mode 2, the UE may keep or maintain these lists of local UEs and may store additional information, such as configuration information, to aid in sidelink coordination.

[0158] FIG. 13 shows two peer UEs 1310 and 1320 with active access links 1302 and 1304, respectively. The UE 1310 may be OFF and may not be transmitting PRS signals to the peer UE 1320. The UE 1320 may transmit SL-PRS 1306 to the UE 1310 even though no signal has been received from the UE 1310 during a defined period. Another sidelink extension is the support of inter-UE cooperation. With inter-UE cooperation, the UE 1320 may assist the UE 1310 in its resource selection. There are two types of inter-UE cooperation, Type A and Type B. Regardless of whether the UE 1310's SL-PRS is ON or OFF, the UE 1320 may directly restrict the use of some resources by the assisted UE 1310 (Type A). The UE 1320 may instruct the UE 1310 to restrict the use of some resources or to recommend which resources should be used (Type B). After receiving the Type B, the UE 1310 may determine whether to use or follow the recommended, restricted, or X resource set sent by the UE 1320. The UE 1320 may also unilaterally restrict the use of its resources for one or more UEs, including the UE 1310, and inform the UE of such restrictions. Sidelink resource information, including DRX configuration information for the UEs, may be received from the access links 1302 and 1304 as well as from peer UEs (e.g., 1310 and 1320).

[0159] FIG. 14 illustrates various sidelink connections between a first UE (labeled “UE1”) and several other UEs (labeled “UE2-7”) utilizing mode 1 resource allocation according to aspects of the disclosure. The connections may be allocated in a sidelink resource pool (RP) provided by a gNB or base station. In the illustrated configuration 1400, UE1 may be involved in a positioning session to determine an estimate of its location, and UE2, UE3, UE4, UE5, UE6, and UE7 may be available or within range to assist UE1. The gNB or other network entity may provide assistance data (AD) to UE1 indicating the SL-PRS configurations of UE2-7 in the configuration 1400. The AD configurations may include SL-DRX configurations for each of UE1-7. There are several UEs with location-based power saving features enabled. For example, UE3 and UE6 may be configured to be in a power saving mode for SL-PRS transmissions (e.g., in a DRX off state) and therefore may not be utilized for positioning. UEs in power saving mode for sidelink (UE3 and UE6) may remain connected to the gNB such that power saving or SL-DRX is applied to sidelink Rx and not to radio unit (DL) signals.

[0160] A location server (e.g., LMF 270) for the gNB in ​​Figure 14 may not be aware of the SL transmission status for each UE, or the power optimization each UE is employing when providing assistance data for a positioning session. Thus, to determine which UEs are transmitting SL-PRS, UE1 may attempt to measure the SL-PRS from each of the other UEs 2-7. However, this may be inefficient and may waste resources of UE1, as not all of UE2-UE7 may be transmitting SL-PRS.

[0161] Thus, the present disclosure provides power saving techniques for sidelink operation. Power saving at the UE may be enabled by determining and reporting SL-PRS status using UE-to-UE positioning coordination signaling. In one implementation, the LMF may provide assistance data including a list of UEs that may be available for positioning. The LMF may maintain and provide configuration information for the UEs along with the assistance data. At any given time, some of the UEs may not be transmitting due to their power saving capabilities. Thus, the LMF's list of UEs ready to assist may not be up to date at any given time. The LMF's list may only indicate that the UEs are configured to provide SL-PRS, and may not indicate that such UEs are actively doing so or are currently capable (enabled) of doing so.

[0162] In one implementation, a UE in Mode 1 resource allocation (e.g., UE1) may maintain transmission / detection status reports for sidelink PRS from nearby UEs. Each of UE1-7 (e.g., UE1 in FIG. 14) may have a process for periodically checking whether the configured SL-PRS / RP-P is detectable. The positioning session configuration received at UE1 may assist UE1 in determining parameters and processes for periodically checking nearby UEs. The LMF may assist UE1 in determining parameters and processes for periodically checking nearby UEs (e.g., UEs on the LMF's list as being SL-PRS configured). For example, the LMF may provide the UE with a positioning session configuration that defines one or more conditions that the UE's measurement of the SL-PRS should meet to confirm that the SL-PRS of another UE is OFF or inactive. The applicable wireless standard may define one or more conditions that the UE's measurement of the SL-PRS should meet to confirm that the SL-PRS of another UE is OFF or inactive. That is, the UE may have (or may be provided via) one or more conditions for determining whether nearby UEs have their SL-PRS OFF (e.g., in inactive SL-DRX mode) despite being configured for SL-PRS or listed in the location server's AD. In this way, UE1 may determine that UE3 and UE6 are not available for SL-PRS support despite being configured for SL-PRS or listed as such. The detecting UE may record a list of UEs that are inactive or undetectable and share the list with other UEs.

[0163] The conditions for determining that the SL-PRS resource is inactive may correspond to several measurements, including Reference Signal Received Power (RSRP) (power level), Signal to Interference and Noise Ratio (SINR) (interference level), and / or Signal to Noise Ratio (SNR) (noise level). The ON / OFF or active / inactive decision may be determined by one or more thresholds corresponding to these or other measurements and may be averaged over a period of time. The AD may include pre-specified conditions that the measurements should satisfy in order to determine or record that the SL-PRS is OFF or inactive. This decision may be stored on the measuring UE to improve the efficiency of that UE. For example, UE1 may stop attempting to measure the SL-PRS from UE3 after determining that UE3 is OFF via one or more of the above conditions. The detecting UE may transmit these conditions for the decision along with the list of inactive UEs.

[0164] Still referring to FIG. 14, UE1, which requires location assistance, may determine that UE3 and UE6 are inactive after some conditions are met as described above. These conditions may be specified by the UE itself, or by the LMF or gNB. In implementation, UE1 may inform the LMF which UEs in the AD have been measured and determined to be OFF. In addition, UE3 or UE6 may inform the LMF and / or peer UEs (e.g., UE1, UE7) that, for example, their device type or configuration may disable SL-PRS without warning. That is, UEs that cannot reliably transmit SL-PRS (e.g., due to SL-DRX) or low-end UEs may inform the LMF and / or their peers that they may deactivate SL-PRS at any time (e.g., puncturable / discontinuous). This puncturability, reliability, and availability information may be determined by the LMF based on configuration information from the UEs, including DRX capabilities, location-based power saving modes, and priority status. Thus, the LMF may store two AD lists: a first list (set) of reliable UEs (and non-puncturable) that may be assumed to be ON if configured for SL-PRS, and a second list (set) of unreliable UEs (puncturable / discontinuous) that may or may not be ON (e.g., conditionally ON). UEs receiving these AD lists may decide by themselves which UEs to contact for positioning assistance or may be instructed to use only the first list (non-puncturable or available UEs).

[0165] UE1 or the LMF may employ implicit rules (conditions) to determine which SL-PRS / RP-Ps may be assumed to be ON and / or which SL-PRS / RP-Ps may be potentially OFF / potentially puncturable. The relevant wireless standard may define rules or conditions to determine which SL-PRS / RP-Ps may be assumed to be ON and / or which SL-PRS / RP-Ps may be potentially OFF / potentially puncturable. For example, low priority SL-PRSs may be assumed to be potentially inactive. The UE and the LMF may determine the UE location assistance reliability by inference from UE configuration data (e.g., presence of DRX configuration), by explicit information from the UE, or by determined status recorded by the UE wanting assistance or other UEs on the network, or by a combination thereof. The assistance data (AD) from the LMF may include transmission certainty data or reliability (puncturability / discontinuity) for each SL-PRS. This certainty data may be used by UEs needing assistance to set signal gain and determine whether to allocate resources to detecting SL-PRS. This certainty data may assist the UE in distinguishing between low signals from the UE and inactive UEs (e.g., with SL-DRX in an inactive state) and reduce power consumed to search for inactive devices.

[0166] UE-to-UE coordination for positioning may include determining that one or more SL-PRS provided by the AD information are actually OFF. If a UE (e.g., UE 7) receives information that some SL-PRS / RP-Ps may potentially be OFF / punctured / inactive, the positioning UE may apply this additional information along with the AD configuration for any measurements. If the UE determines that one or more conditions of the AD configuration are met by the measurements, the UE may stop measuring the SL-PRSs determined to be not transmitted for a period of time. The UE may inform the LMF whether the measured SL-PRS resources are ON or may potentially be OFF in the future. The UE may inform nearby UEs (e.g., in the RP) that it has determined that these SL-PRS resources are considered to be OFF, along with thresholds for the decision, associated measurements, specifications, or other decision factors. That is, different UEs may have different conditions for determining that SL-PRS / RP-Ps are OFF, for example, based on their respective hardware capabilities.

[0167] Continuing to refer to FIG. 14, in Mode 2 resource allocation, UE-to-UE coordination for positioning may be used to determine one or more SL-PRS are OFF or inactive. At any given time, some of the UEs (e.g., UE3) may not be transmitting SL-PRS (e.g., due to power saving function or DRX period). One UE (primary UE) may maintain a record of active / inactive status of SL-PRS transmission by nearby UEs by signal measurement or UE-to-UE coordination signaling. This UE in Mode 2 may report the measured SL-PRS status of other UEs to nearby UEs along with a timestamp, a set of timestamps, measurement conditions, and / or other information that forms the status determination. Each UE may have a threshold for determining the status of other UEs. For example, if a SL-PRS / RP-P resource is determined to be OFF for longer than X milliseconds or for at least Y instances (where X and Y may be integers), the UE is not expected to include that SL-PRS resource in UE-to-UE coordination signaling. In other words, the UE may have a reliability metric that must be met to determine that a particular SL-PRS / RP-P resource has been turned OFF.

[0168] A UE may request the SL-PRS transmission status of nearby UEs via UE-to-UE coordinated signaling. Similarly, broadcast, groupcast, or unicast signaling may be used to inform nearby UEs about the status of SL-PRS. The anchor UE, which manages the resource pool, may perform a positioning resource reallocation procedure after obtaining the transmission status for SL UEs in its area (i.e., in the RP-P or on the AD list). The anchor UE may perform the detection and determination of the transmission / activity status (e.g., ON / OFF) by itself before the positioning resource reallocation procedure. The anchor UE may perform any of the notification features performed by the LMF described earlier (e.g., AD broadcast).

[0169] A UE (e.g., UE3) may be configured to enable or activate SL PRS resource transmission based on location. That is, the DRX mode may be location-based DRX as shown in FIG. 12, where some UEs are in DRX inactive state based on their location (e.g., indoors). Similarly, the DRX mode may be a motion-based or motion-activated power saving feature (e.g., a wearable that sleeps in DRX inactive until moved). The location may be associated with the proximity to other UEs (e.g., in a workplace). Even if the UE is configured for DRX, the transmission condition of the UE may be predictable, for example, by the LMF. That is, the LMF may be adapted to predict when the UE will enter a DRX off state based on a location criterion and may include the UE in its AD list unless the location criterion is met. If the UE is in a particular zone or has not moved from an initial zone where it provided SL-PRS, the UE is expected to transmit SL-PRS, regardless of the SL-DRX configuration. If the LMF or anchor UE detects that a SL-DRX configured device is moving towards a deactivation zone (where DRX becomes inactive), the LMF may remove the UE from the AD list.

[0170] A UE may be allowed (or determined) to transmit SL-PRS in the DRX off state based on the UE's decision. For example, if the SL-PRS resource is associated with a high priority status, this status may override the DRX off state and the SL-PRS is transmitted despite the UE being in the DRX off state. The UE may report that even if it is configured for DRX, if the UE has a high priority status or is in a high priority RP, the UE may inform other UEs or the LMF that its DRX period is overridden. The SL-PRS for the UE may be transmitted even during the DRX off period when it is high priority. The UE may include an override configuration that allows positioning resource transmission during location-based DRX off periods. As a result, the UE may be used as a positioning reference during the DRX period.

[0171] The UE may request on-demand SL-PRS resources or high priority status based on its configuration in Mode 1 or Mode 2, so that the requesting UE is provided with only SL-PRS resources that are expected to be ON / not puncturable. That is, the UE may request that the AD list includes only reliable UEs for position assistance. The base station / radio unit (in Mode 1) or anchor UE (in Mode 2) may interpret the request for high priority positioning as a request for on-demand SL-PRS resources that are not puncturable or discontinuously OFF. The request may include minimum time period or time window information during which the SL-PRS resources are expected to be ON. The request is received by the LMF and / or other SL UEs. One or more of the UEs receiving the request may switch to transmit-only mode to grant the requesting UE on-demand SL-PRS resources.

[0172] A UE designated to transmit such a SL-PRS to the requesting peer UE is expected to drop other conflicting Tx channels and other conflicting Rx channels. For example, a SL UE may not switch to Rx mode as it normally would, but instead remain on dedicated or on-demand SL-PRS transmission resources for a defined period of time. Overriding the Rx mode of the SL transceiver ensures that an on-demand UE transmits the SL-PRS and that the SL-PRS is not queued or delayed by other transmissions. For longer periods of requested on-demand SL-PRS resources, the LMF or anchor UE may cycle or periodically forward on-demand duty. For example, emergency responder UEs may request high priority or on-demand resources as long as they are on-site or responding.

[0173] FIG. 15 illustrates an example method 1500 of wireless communication according to an aspect of the disclosure. In one aspect, the method 1500 may be performed by a UE (e.g., any of the UEs described herein). At 1502, the UE may receive a configuration of a first set of sidelink positioning reference signal (SL-PRS) resources configured for transmission by a first set of sidelink UEs including the UE. In one aspect, the operation 1502 may be performed by one or more transceivers 310-320, one or more processors 332, memory 340, and / or positioning component 342, any or all of which may be considered as a means for performing this operation.

[0174] At 1504, the UE may determine a sidelink transmission status for a first subset of the SL-PRS resources of the first set of SL-PRS resources based on signal strength measurements of the first set of SL-PRS resources, availability information for the first set of SL-PRS resources, or both. In one aspect, operation 1504 may be performed by one or more transceivers 310-320, one or more processors 332, memory 340, and / or positioning component 342, any or all of which may be considered as a means for performing this operation.

[0175] As can be appreciated, a technical advantage of method 1500 is power conservation.

[0176] The determination of method 1500 may include determining a sidelink transmission status of a first subset of SL-PRS resources to be inactive based on a signal strength measurement for the first subset of SL-PRS resources being below a threshold, and determining a sidelink transmission status of a second subset of SL-PRS resources to be active based on a signal strength measurement for the second subset of SL-PRS resources being above a threshold. The signal strength measurement may include a power level, a noise level, or an interference level, or any combination thereof. The threshold may be received from a location server or a base station. Method 1500 may report the sidelink transmission status of the first subset of SL-PRS resources to at least one additional UE that shares the first set of SL-PRS resources. The availability information for the first set of SL-PRS resources indicates available SL-PRS resources and conditionally available SL-PRS resources. Available SL-PRS resources are configured to be transmitted, and conditionally available SL-PRS resources are non-contiguous, puncturable, or conditionally active.

[0177] At least a portion of the availability information for the first set of SL-PRS resources may be received in a configuration. Some availability information may be high level (e.g., the device has DRX mode capability) and included in the configuration from the AD or the network node. Other availability information may be sourced from other UEs, such as "DRX mode is enabled" or "what location trigger switches the device to DRX off mode". The availability information for the first set of SL-PRS resources may be received from a first UE of the first set of sidelink UEs or from a network node. The availability information for the first set of SL-PRS resources indicates a discontinuous reception (DRX) mode or a power saving mode of a second UE of the first set of sidelink UEs. The availability information for the first set of SL-PRS resources may include configuration information related to location-based triggers for the DRX mode or the power saving mode. The availability information for the first set of SL-PRS resources may be received from a location server or a network node and may include criteria for determining a time period during which the SL-PRS is configured to be transmitted by at least one other UE of the first set of sidelink UEs, the criteria including a DRX mode configuration of the at least one other UE.

[0178] The determination of method 1500 may include determining a sidelink transmission status of a first subset of SL-PRS resources as active or inactive after a defined time period based on a signal strength measurement detected at the UE. The sidelink transmission status of the first subset of SL-PRS resources is recorded with a timestamp. The determination of method 1500 may include determining a sidelink transmission status of the first subset of SL-PRS resources based on the presence or absence of an associated SL-PRS within a defined time period or for a given number of expected transmission instances. Method 1500 may include transmitting to the first set of sidelink UEs a first sidelink transmission status of the UE as active or inactive via inter-UE coordination. Method 1500 may include allocating, by the UE, a resource pool of the first set of SL-PRS resources based on the sidelink transmission status of the first subset of SL-PRS resources. The method 1500 may include receiving, at the UE, configuration information associated with an additional UE in a first set of sidelink UEs, predicting, at the UE, SL-PRS availability for the additional UE based on the configuration information, and transmitting assistance data (AD), where the AD is based on the predicted SL-PRS availability. Predicting the SL-PRS availability for the additional UE may be based on the configuration information and a location of the additional UE.

[0179] The further UEs of the first set of sidelink UEs may be configured in a discontinuous reception (DRX) mode, and the UE predicts that the DRX mode is disabled for the further UEs at the location based on a previous SL-PRS transmission from the further UE at the location. Receiving configuration information may be associated with the further UEs of the first set of sidelink UEs, and reserving SL-PRS resources of the resource pool for the further UEs may be based on the configuration information and a priority status of the further UE. The further UEs may be in an inactive time of the DRX mode.

[0180] FIG. 16 illustrates an example method 1600 of wireless communication according to aspects of the disclosure. In one aspect, the method 1600 may be performed by a UE (e.g., any of the UEs described herein). At 1602, the UE may receive configuration information associated with a location-based discontinuous reception (DRX) mode. In one aspect, the operation 1602 may be performed by one or more transceivers 310-320, one or more processors 332, memory 340, and / or a positioning component 342, any or all of which may be considered as means for performing this operation. At 1604, the UE may obtain a location of the UE. In one aspect, the operation 1604 may be performed by one or more transceivers 310-320, one or more processors 332, memory 340, and / or a positioning component 342, any or all of which may be considered as means for performing this operation.

[0181] At 1606, the UE may transmit a sidelink positioning reference signal (SL-PRS) based on the location while in an inactive state of a location-based discontinuous reception (DRX) mode. The DRX mode may be associated with a downlink signal or a PDCCH signal. In an aspect, the operation 1606 may be performed by one or more transceivers 310-320, one or more processors 332, memory 340, and / or positioning component 342, any or all of which may be considered as a means for performing this operation.

[0182] As can be appreciated, the technical advantages of method 1600 include power conservation and improved location awareness.

[0183] The location of the UE is based on satellite signals, cellular signals, Wi-Fi signals, sensor information, or any combination thereof. Transmitting the SL-PRS at 1606 may be associated with a priority status or an on-demand request, and the SL-PRS monitoring capability is discontinuous in the DRX mode.

[0184] 17 illustrates an example method 1700 of wireless communication according to an aspect of the disclosure. In one aspect, the method 1700 may be performed by a UE (e.g., any of the UEs described herein).

[0185] At 1702, a UE may receive a request to transmit an on-demand sidelink position reference signal (SL-PRS) along with a time period during which the UE is requested to transmit the SL-PRS. In an aspect, operation 1702 may be performed by one or more transceivers 310-320, one or more processors 332, memory 340, and / or positioning component 342, any or all of which may be considered a means for performing this operation.

[0186] At 1704, the UE may refrain from transmitting, receiving, or both over transmit channels, receive channels, or both that conflict with the requested on-demand SL-PRS. In one aspect, operation 1704 may be performed by one or more transceivers 310-320, one or more processors 332, memory 340, and / or positioning component 342, any or all of which may be considered a means for performing this operation.

[0187] At 1706, the UE may transmit the requested on-demand SL-PRS. The request for on-demand SL-PRS may override the DRX mode or power save mode for the time period based on the request. The request is received from a location server, a network node, or the second UE. In an aspect, operation 1706 may be performed by one or more transceivers 310-320, one or more processors 332, memory 340, and / or positioning component 342, any or all of which may be considered as a means for performing this operation.

[0188] As can be appreciated, technical advantages of method 1700 include power conservation and improved location awareness.

[0189] In the above detailed description, it can be seen that in each example, various features are grouped together. This manner of disclosure should not be understood as an intention that the exemplary clauses have more features than are expressly stated in each clause. Rather, various aspects of the disclosure may include fewer features than all features of each disclosed exemplary clause. Thus, the following clauses should be considered to be incorporated in the 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 in the clause, the aspect(s) of the dependent clause are not limited to that specific combination. It will be understood that other exemplary clauses may also include combinations of the aspect(s) of the dependent clause with the subject matter of any other dependent clause or independent clause, or any combination of features with other dependent clauses and independent clauses. Various aspects disclosed herein expressly include these combinations, unless it is expressly expressed or can be easily inferred that a particular combination is not intended (e.g., inconsistent aspects, such as defining an element as both an electrical insulator and an electrical conductor). It is further contemplated that aspects of a clause may be included in any other independent clause, even if the clause is not directly dependent on the independent clause.

[0190] The following numbered clauses describe example implementations.

[0191] Clause 1. A method of wireless communications performed by a user equipment (UE), the method comprising: receiving a configuration of a first set of sidelink positioning reference signal (SL-PRS) resources configured for transmission by a first set of sidelink UEs including the UE; and determining a sidelink transmission status of a first subset of SL-PRS resources of the first set of SL-PRS resources based on signal strength measurements of the first set of SL-PRS resources, availability information for the first set of SL-PRS resources, or both.

[0192] Clause 2. The method of clause 1, wherein the determining further includes determining a sidelink transmission status of a first subset of SL-PRS resources to be inactive based on a signal strength measurement for the first subset of SL-PRS resources being below a threshold, and determining a sidelink transmission status of a second subset of SL-PRS resources to be active based on a signal strength measurement for the second subset of SL-PRS resources being above a threshold, the signal strength measurement including a power level, a noise level, or an interference level, or any combination thereof.

[0193] Clause 3. The method of clause 2, wherein the threshold value is received from a location server or a base station.

[0194] Clause 4. The method of any of clauses 1 to 3, further comprising reporting a sidelink transmission status of the first subset of SL-PRS resources to at least one additional UE sharing the first set of SL-PRS resources.

[0195] Clause 5. The method of any of clauses 1 to 4, wherein the availability information for the first set of SL-PRS resources indicates available SL-PRS resources and conditionally available SL-PRS resources, the available SL-PRS resources being configured to be transmitted, and the conditionally available SL-PRS resources being non-contiguous, puncturable, or conditionally active.

[0196] Clause 6. A method according to any of clauses 1 to 5, wherein at least a portion of the availability information for the first set of SL-PRS resources is received in a configuration.

[0197] Clause 7. The method of any of clauses 1 to 6, wherein availability information for a first set of SL-PRS resources is received from a first UE of the first set of sidelink UEs or a network node, and the availability information for the first set of SL-PRS resources indicates a discontinuous reception (DRX) mode or a power saving mode of a second UE of the first set of sidelink UEs.

[0198] Clause 8. The method of clause 7, wherein the availability information for the first set of SL-PRS resources includes configuration information related to location-based triggers for a DRX mode or a power saving mode.

[0199] Clause 9. A method according to any of clauses 1 to 8, wherein the availability information for the first set of SL-PRS resources is received from a location server or a network node and includes criteria for determining a time period during which the SL-PRS is configured to be transmitted by at least one other UE of the first set of sidelink UEs, the criteria including a DRX mode configuration of the at least one other UE.

[0200] Clause 10. The method of any of clauses 1 to 9, wherein determining further comprises determining a sidelink transmission status of a first subset of SL-PRS resources as active or inactive after a defined period of time based on signal strength measurements detected at the UE.

[0201] Clause 11. The method of any of clauses 1 to 10, wherein the sidelink transmission status of the first subset of SL-PRS resources is recorded together with a timestamp.

[0202] Clause 12. The method of any of clauses 1 to 11, wherein determining further comprises determining the sidelink transmission status of a first subset of SL-PRS resources based on the presence or absence of an associated SL-PRS within a defined time period or for a given number of expected transmission instances.

[0203] Clause 13. The method of any of clauses 1 to 12, further comprising transmitting, to a first set of sidelink UEs, via inter-UE coordination, a first sidelink transmission status of the UE as active or inactive.

[0204] Clause 14. The method of any of clauses 1 to 13, further comprising allocating, by the UE, a resource pool of the first set of SL-PRS resources based on a sidelink transmission status of the first subset of the SL-PRS resources.

[0205] Clause 15. A method according to any of clauses 1 to 14, further comprising receiving, in the UE, configuration information associated with a further UE in the first set of sidelink UEs, predicting, in the UE, SL-PRS availability for the further UE based on the configuration information, and transmitting assistance data (AD), the AD being based on the predicted SL-PRS availability.

[0206] Clause 16. The method of clause 15, wherein predicting SL-PRS availability for the further UE is based on configuration information and a location of the further UE.

[0207] Clause 17. The method of any of clauses 1 to 16, wherein a further UE of the first set of sidelink UEs is configured in discontinuous reception (DRX) mode, and the UE predicts that DRX mode will be disabled for the further UE at the location based on a previous SL-PRS transmission from the further UE at the location.

[0208] Clause 18. The method of any of clauses 1 to 17, further comprising receiving configuration information associated with a further UE of the first set of sidelink UEs and reserving SL-PRS resources of the resource pool for the further UE based on the configuration information and a priority status of the further UE, wherein the further UE is in an inactive time of the DRX mode.

[0209] Clause 19. A method of wireless communication performed by a user equipment (UE), comprising: receiving configuration information associated with a location-based discontinuous reception (DRX) mode; obtaining a location of the UE; and transmitting a sidelink positioning reference signal (SL-PRS) based on the location while in an inactive state of the location-based DRX mode.

[0210] Clause 20. The method of clause 19, wherein the location of the UE is based on satellite signals, cellular signals, Wi-Fi signals, sensor information, or any combination thereof.

[0211] Clause 21. The method according to clause 19 or 20, wherein transmitting the SL-PRS is associated with a priority status or an on-demand request, and the SL-PRS monitoring capability is discontinuous in DRX mode.

[0212] Clause 22. A method of wireless communications performed by a user equipment (UE), comprising: receiving a request to transmit an on-demand sidelink position reference signal (SL-PRS) together with a time period during which the UE is requested to transmit the SL-PRS; refraining from transmitting, receiving, or both over a transmission channel, a reception channel, or both that conflicts with the requested on-demand SL-PRS; and transmitting the requested on-demand SL-PRS.

[0213] Clause 23. The method of clause 22, wherein the request is received from a location server, a network node, or a second UE.

[0214] Clause 24. The method of clause 22 or 23, further comprising overriding the DRX off period for a period of time upon request.

[0215] Clause 25. A user equipment (UE), comprising: a memory; at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, wherein the at least one processor is configured to receive, via the at least one transceiver, a configuration of a first set of sidelink positioning reference signal (SL-PRS) resources configured for transmission by a first set of sidelink UEs, and to determine a sidelink transmission status of a first subset of the SL-PRS resources of the first set of SL-PRS resources based on signal strength measurements of the first set of SL-PRS resources, availability information of the first set of SL-PRS resources, or both.

[0216] Clause 26. The UE of Clause 25, wherein the at least one processor configured to determine includes at least one processor configured to determine a sidelink transmission status of a first subset of SL-PRS resources to be inactive based on a signal strength measurement for the first subset of SL-PRS resources being below a threshold, and to determine a sidelink transmission status of a second subset of SL-PRS resources to be active based on a signal strength measurement for the second subset of SL-PRS resources being above a threshold, wherein the signal strength measurement includes a power level, a noise level, or an interference level, or any combination thereof.

[0217] Clause 27. The UE of clause 26, wherein the threshold value is received from a location server.

[0218] Clause 28. The UE of any of clauses 25 to 27, wherein the at least one processor is further configured to report, via the at least one transceiver, a sidelink transmission status of the first subset of SL-PRS resources to at least one additional UE that shares the first set of SL-PRS resources.

[0219] Clause 29. A UE as described in any of clauses 25 to 28, wherein the availability information for the first set of SL-PRS resources indicates available SL-PRS resources and conditionally available SL-PRS resources, the available SL-PRS resources being configured to be transmitted, and the conditionally available SL-PRS resources being non-contiguous, puncturable or conditionally active.

[0220] Clause 30. A UE according to any of clauses 25 to 29, wherein at least a portion of the availability information for the first set of SL-PRS resources is received in configuration.

[0221] Clause 31. A UE as described in any of clauses 25 to 30, wherein availability information for a first set of SL-PRS resources is received from a first UE of the first set of sidelink UEs or a network node, and the availability information for the first set of SL-PRS resources indicates a discontinuous reception (DRX) mode or a power saving mode of a second UE of the first set of sidelink UEs.

[0222] Clause 32. The UE of clause 31, wherein the availability information for the first set of SL-PRS resources includes configuration information related to location-based triggers for a DRX mode or a power saving mode.

[0223] Clause 33. A UE as described in any of clauses 25 to 32, wherein the availability information for the first set of SL-PRS resources is received from a location server or a network node and includes criteria for determining a time period during which the SL-PRS is configured to be transmitted by at least one other UE of the first set of sidelink UEs, the criteria including a DRX mode configuration of the at least one other UE.

[0224] Clause 34. A UE as described in any of clauses 25 to 33, wherein the at least one processor configured to determine comprises at least one processor configured to determine, after a defined period of time, a sidelink transmission status of a first subset of SL-PRS resources as active or inactive based on signal strength measurements detected at the UE.

[0225] Clause 35. The UE of any of clauses 25 to 34, wherein the sidelink transmission status of the first subset of SL-PRS resources is recorded together with a timestamp.

[0226] Clause 36. The UE of any of clauses 25 to 35, wherein the at least one processor configured to determine comprises at least one processor configured to determine the sidelink transmission status of a first subset of SL-PRS resources based on the presence or absence of an associated SL-PRS within a defined time period or for a given number of expected transmission instances.

[0227] Clause 37. The UE of any of clauses 25 to 36, further comprising transmitting, via inter-UE coordination, to a first set of sidelink UEs, a first sidelink transmission status of the UE as active or inactive.

[0228] Clause 38. The UE of any of clauses 25 to 37, wherein the at least one processor is further configured to allocate a resource pool of the first set of SL-PRS resources based on a sidelink transmission status of the first subset of the SL-PRS resources.

[0229] Clause 39. A UE as described in any of clauses 25 to 38, wherein the at least one processor is further configured to receive, in the UE via the at least one transceiver, configuration information associated with a further UE in the first set of sidelink UEs, and in the UE, predict SL-PRS availability for the further UE based on the configuration information, and transmit, in the UE, assistance data (AD) via the at least one transceiver, the AD being based on the predicted SL-PRS availability.

[0230] Clause 40. A UE as claimed in clause 39, wherein the UE predicts SL-PRS availability for the further UE based on the configuration information and the location of the further UE.

[0231] Clause 41. A UE as described in any of clauses 25 to 40, wherein a further UE of the first set of sidelink UEs is configured in discontinuous reception (DRX) mode, and the UE predicts that DRX mode will be disabled for the further UE at the location based on a previous SL-PRS transmission from the further UE at the location.

[0232] Clause 42. A UE according to any of clauses 25 to 41, wherein the at least one processor is further configured to receive, via the at least one transceiver, configuration information associated with a further UE of the first set of sidelink UEs, and to reserve SL-PRS resources of the resource pool for the further UE based on the configuration information and a priority status of the further UE, the further UE being in an inactive time of the DRX mode.

[0233] Clause 43. 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, via the at least one transceiver, configuration information associated with a location-based discontinuous reception (DRX) mode, obtain a location of the UE, and transmit, via the at least one transceiver, a sidelink positioning reference signal (SL-PRS) based on the location while in an inactive state of the location-based DRX mode.

[0234] Clause 44. The UE of clause 43, wherein the location of the UE is based on satellite signals, cellular signals, Wi-Fi signals, sensor information, or any combination thereof.

[0235] Clause 45. The UE of clause 43 or 44, wherein the UE transmitting the SL-PRS is associated with a priority status or an on-demand request, and the SL-PRS monitoring capability is discontinuous in DRX mode.

[0236] Clause 46. 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 request to transmit an on-demand sidelink position reference signal (SL-PRS) via the at least one transceiver along with a time period during which the UE is requested to transmit the SL-PRS; refrain from transmitting, receiving, or both via a transmit channel, a receive channel, or both that conflicts with the requested on-demand SL-PRS; and transmit the requested SL-PRS via the at least one transceiver.

[0237] Clause 47. The UE of clause 46, wherein the request is received from a location server, a network node, or a second UE.

[0238] Clause 48. The UE of clause 46 or 47, wherein the at least one processor is further configured to override the DRX off period for a period of time based on the request.

[0239] Clause 49. A user equipment (UE), comprising: means for receiving a configuration of a first set of sidelink positioning reference signal (SL-PRS) resources configured for transmission by a first set of sidelink UEs including the UE; and means for determining a sidelink transmission status of a first subset of SL-PRS resources of the first set of SL-PRS resources based on signal strength measurements of the first set of SL-PRS resources, availability information for the first set of SL-PRS resources, or both.

[0240] Clause 50. The UE of clause 49, wherein the determining further comprises means for determining that a sidelink transmission status of a first subset of SL-PRS resources is inactive based on a signal strength measurement for the first subset of SL-PRS resources being below a threshold, and means for determining that a sidelink transmission status of a second subset of SL-PRS resources is active based on a signal strength measurement for the second subset of SL-PRS resources being above a threshold, the signal strength measurement comprising a power level, a noise level, or an interference level, or any combination thereof.

[0241] Clause 51. The UE of clause 50, wherein the threshold is received from a location server or a base station.

[0242] Clause 52. The UE of any of clauses 49 to 51, further comprising means for reporting sidelink transmission status of the first subset of SL-PRS resources to at least one further UE sharing the first set of SL-PRS resources.

[0243] Clause 53. A UE as described in any of clauses 49 to 52, wherein the availability information for the first set of SL-PRS resources indicates available SL-PRS resources and conditionally available SL-PRS resources, the available SL-PRS resources being configured to be transmitted, and the conditionally available SL-PRS resources being non-contiguous, puncturable or conditionally active.

[0244] Clause 54. A UE according to any of clauses 49 to 53, wherein at least a portion of the availability information for the first set of SL-PRS resources is received in configuration.

[0245] Clause 55. A UE as described in any of clauses 49 to 54, wherein availability information for the first set of SL-PRS resources is received from a first UE of the first set of sidelink UEs or a network node, and the availability information for the first set of SL-PRS resources indicates a discontinuous reception (DRX) mode or a power saving mode of a second UE of the first set of sidelink UEs.

[0246] Clause 56. The UE of clause 55, wherein the availability information for the first set of SL-PRS resources includes configuration information related to location-based triggers for a DRX mode or a power saving mode.

[0247] Clause 57. A UE as described in any of clauses 49 to 56, wherein the availability information for the first set of SL-PRS resources is received from a location server or a network node and includes criteria for determining a time period during which the SL-PRS is configured to be transmitted by at least one other UE of the first set of sidelink UEs, the criteria including a DRX mode configuration of the at least one other UE.

[0248] Clause 58. A UE as described in any of clauses 49 to 57, wherein determining further comprises means for determining a sidelink transmission status of a first subset of SL-PRS resources as active or inactive after a defined period of time based on signal strength measurements detected at the UE.

[0249] Clause 59. The UE of any of clauses 49 to 58, wherein the sidelink transmission status of the first subset of SL-PRS resources is recorded together with a timestamp.

[0250] Clause 60. The UE of any of clauses 49 to 59, wherein determining further comprises means for determining a sidelink transmission status of a first subset of SL-PRS resources based on the presence or absence of an associated SL-PRS within a defined time period or for a given number of expected transmission instances.

[0251] Clause 61. The UE of any of clauses 49 to 60, further comprising means for transmitting, via inter-UE coordination, to a first set of sidelink UEs, a first sidelink transmission status of the UE as active or inactive.

[0252] Clause 62. The UE of any of clauses 49 to 61, further comprising means for allocating a resource pool of the first set of SL-PRS resources based on a sidelink transmission status of the first subset of the SL-PRS resources.

[0253] Clause 63. A UE as described in any of clauses 49 to 62, further comprising: means, in the UE, for receiving configuration information associated with a further UE in the first set of sidelink UEs; means, in the UE, for predicting SL-PRS availability for the further UE based on the configuration information; and means for transmitting assistance data (AD), the AD being based on the predicted SL-PRS availability.

[0254] Clause 64. The UE of clause 63, wherein predicting SL-PRS availability for the further UE is based on configuration information and a location of the further UE.

[0255] Clause 65. A UE as described in any of clauses 49 to 64, wherein a further UE of the first set of sidelink UEs is configured in discontinuous reception (DRX) mode, and the UE predicts that DRX mode will be disabled for the further UE at the location based on a previous SL-PRS transmission from the further UE at the location.

[0256] Clause 66. The UE of any of clauses 49 to 65, further comprising receiving configuration information associated with a further UE of the first set of sidelink UEs and reserving SL-PRS resources of the resource pool for the further UE based on the configuration information and the priority status of the further UE, the further UE being in an inactive time of the DRX mode.

[0257] Clause 67. A UE, comprising: means for receiving configuration information associated with a location-based discontinuous reception (DRX) mode; means for acquiring a location of the UE; and means for transmitting a sidelink positioning reference signal (SL-PRS) based on the location while in an inactive state of the location-based DRX mode.

[0258] Clause 68. The UE of clause 67, wherein the location of the UE is based on satellite signals, cellular signals, Wi-Fi signals, sensor information, or any combination thereof.

[0259] Clause 69. The UE of clause 67 or 68, wherein transmitting the SL-PRS is associated with a priority status or an on-demand request, and the SL-PRS monitoring capability is discontinuous in the DRX mode.

[0260] Clause 70. A UE comprising: means for receiving a request to transmit an on-demand sidelink position reference signal (SL-PRS) together with a time period during which the UE is requested to transmit the SL-PRS; means for refraining from transmitting, receiving, or both over a transmission channel, a reception channel, or both that conflicts with the requested on-demand SL-PRS; and means for transmitting the requested on-demand SL-PRS.

[0261] Clause 71. The UE of clause 70, wherein the request is received from a location server, a network node, or a second UE.

[0262] Clause 72. The UE of clause 70 or 71, further comprising means for overriding the DRX off period for a period of time upon request.

[0263] Clause 73. A non-transitory computer-readable medium having stored thereon computer-executable instructions that, when executed by a user equipment (UE), cause the UE to receive a configuration of a first set of Sidelink Positioning Reference Signal (SL-PRS) resources configured for transmission by a first set of sidelink UEs that include the UE, and determine a sidelink transmission status of a first subset of the SL-PRS resources of the first set of SL-PRS resources based on signal strength measurements of the first set of SL-PRS resources, availability information for the first set of SL-PRS resources, or both.

[0264] Clause 74. The non-transitory computer-readable medium of clause 73, wherein determining further includes determining a sidelink transmission status of a first subset of SL-PRS resources to be inactive based on a signal strength measurement for the first subset of SL-PRS resources being below a threshold, and determining a sidelink transmission status of a second subset of SL-PRS resources to be active based on a signal strength measurement for the second subset of SL-PRS resources being above a threshold, the signal strength measurement including a power level, a noise level, or an interference level, or any combination thereof.

[0265] Clause 75. The non-transitory computer-readable medium of clause 74, wherein the threshold is received from a location server or a base station.

[0266] Clause 76. A non-transitory computer-readable medium according to any of clauses 73 to 75, further comprising computer-executable instructions that, when executed by a UE, cause the UE to report a sidelink transmission status of a first subset of the SL-PRS resources to at least one additional UE that shares the first set of SL-PRS resources.

[0267] Clause 77. A non-transitory computer-readable medium as described in any of clauses 73 to 76, wherein the availability information for the first set of SL-PRS resources indicates available SL-PRS resources and conditionally available SL-PRS resources, the available SL-PRS resources being configured to be transmitted, and the conditionally available SL-PRS resources being non-contiguous, puncturable, or conditionally active.

[0268] Clause 78. The non-transitory computer-readable medium of any of clauses 73 to 77, wherein at least a portion of the availability information for the first set of SL-PRS resources is received in a configuration.

[0269] Clause 79. A non-transitory computer-readable medium according to any of clauses 73 to 78, wherein availability information for a first set of SL-PRS resources is received from a first UE of the first set of sidelink UEs or a network node, and the availability information for the first set of SL-PRS resources indicates a discontinuous reception (DRX) mode or a power saving mode of a second UE of the first set of sidelink UEs.

[0270] Clause 80. The non-transitory computer-readable medium of clause 79, wherein the availability information for the first set of SL-PRS resources includes configuration information related to a location-based trigger for a DRX mode or a power saving mode.

[0271] Clause 81. A non-transitory computer-readable medium according to any of clauses 73 to 80, wherein the availability information for the first set of SL-PRS resources is received from a location server or a network node and includes criteria for determining a time period during which the SL-PRS is configured to be transmitted by at least one other UE of the first set of sidelink UEs, the criteria including a DRX mode configuration of the at least one other UE.

[0272] Clause 82. The non-transitory computer-readable medium of any of clauses 73 to 81, wherein determining further comprises determining a sidelink transmission status of a first subset of SL-PRS resources as active or inactive after a defined period of time based on signal strength measurements detected at the UE.

[0273] Clause 83. The non-transitory computer-readable medium of any of clauses 73 to 82, wherein the sidelink transmission status of the first subset of SL-PRS resources is recorded together with a timestamp.

[0274] Clause 84. The non-transitory computer-readable medium of any of clauses 73 to 83, wherein determining further comprises determining a sidelink transmission status of a first subset of SL-PRS resources based on the presence or absence of an associated SL-PRS within a defined time period or for a given number of expected transmission instances.

[0275] Clause 85. A non-transitory computer-readable medium according to any of clauses 73 to 84, further comprising computer-executable instructions that, when executed by a UE, cause the UE to transmit, via inter-UE coordination, a first sidelink transmission status of the UE as active or inactive to a first set of sidelink UEs.

[0276] Clause 86. A non-transitory computer-readable medium according to any of clauses 73 to 85, further comprising computer-executable instructions that, when executed by a UE, cause the UE to allocate a resource pool of a first set of SL-PRS resources based on a sidelink transmission status of the first subset of the SL-PRS resources.

[0277] Clause 87. A non-transitory computer-readable medium according to any of clauses 73 to 86, further comprising computer-executable instructions which, when executed by the UE, cause the UE to receive configuration information associated with further UEs in a first set of sidelink UEs, and, based on the configuration information, cause the UE to predict SL-PRS availability for the further UE, and transmit assistance data (AD), wherein the AD is based on the predicted SL-PRS availability.

[0278] Clause 88. The non-transitory computer-readable medium of clause 87, wherein predicting SL-PRS availability for the further UE is based on the configuration information and a location of the further UE.

[0279] Clause 89. A non-transitory computer-readable medium according to any of clauses 73 to 88, wherein a further UE of the first set of sidelink UEs is configured in discontinuous reception (DRX) mode, and the UE predicts that DRX mode will be disabled for the further UE at the location based on a previous SL-PRS transmission from the further UE at the location.

[0280] Clause 90. A non-transitory computer-readable medium according to any of clauses 73 to 89, further comprising computer-executable instructions which, when executed by the UE, cause the UE to receive configuration information associated with a further UE of a first set of sidelink UEs and to reserve SL-PRS resources of the resource pool for the further UE based on the configuration information and a priority status of the further UE, the further UE being in an inactive time of a DRX mode.

[0281] Clause 91. A non-transitory computer-readable medium having stored thereon computer-executable instructions that, when executed by a UE, cause the UE to receive configuration information associated with a location-based discontinuous reception (DRX) mode, obtain a location of the UE, and transmit a sidelink positioning reference signal (SL-PRS) based on the location while in an inactive state of the location-based DRX mode.

[0282] Clause 92. The non-transitory computer-readable medium of clause 91, wherein the location of the UE is based on satellite signals, cellular signals, Wi-Fi signals, sensor information, or any combination thereof.

[0283] Clause 93. The non-transitory computer-readable medium of clause 91 or 92, wherein transmitting the SL-PRS is associated with a priority status or an on-demand request, and the SL-PRS monitoring capability is discontinuous in DRX mode.

[0284] Clause 94. A non-transitory computer-readable medium having stored thereon computer-executable instructions that, when executed by a UE, cause the UE to receive a request to transmit an on-demand sidelink position reference signal (SL-PRS) along with a time period during which the UE is requested to transmit the SL-PRS, refrain from transmitting, receiving, or both over a transmit channel, receive channel, or both that conflicts with the requested on-demand SL-PRS, and transmit the requested on-demand SL-PRS.

[0285] Clause 95. The non-transitory computer-readable medium of clause 94, wherein the request is received from a location server, a network node, or a second UE.

[0286] Clause 96. The non-transitory computer-readable medium of clause 94 or 95, further comprising computer-executable instructions that, when executed by a UE, cause the UE to override the DRX off period for a period of time upon request.

[0287] 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 referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0288] Moreover, those skilled in the art will appreciate that the various exemplary logic 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 exemplary 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 realize the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0289] 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 digital signal processor (DSP), an ASIC, a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but 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.

[0290] The methods, sequences, and / or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in a random access memory (RAM), a flash memory, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a register, a hard disk, a removable disk, a 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 a user terminal.

[0291] 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 via a computer-readable medium as one or more instructions or code. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage medium may be any available medium that 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 the 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 media. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks typically reproduce data magnetically and discs reproduce data optically using lasers. Combinations of the above are also intended to be included within the scope of computer-readable media.

[0292] Although the above disclosure illustrates exemplary aspects of the disclosure, it should be noted that various changes and modifications may be made herein without departing from the scope of the disclosure as defined by the appended claims. The functions, steps, and / or actions of the method claims in accordance with the aspects of the disclosure described herein need not be performed in any particular order. Further, although elements of the disclosure may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.

Claims

1. 1. A method of wireless communication performed by a user equipment (UE), comprising: receiving configuration information associated with a location-based discontinuous reception (DRX) mode; obtaining a location of the UE; transmitting a sidelink positioning reference signal (SL-PRS) based on the location while in an inactive state of the location-based DRX mode.

2. The method of claim 1 , wherein the location of the UE is based on satellite signals, cellular signals, Wi-Fi signals, sensor information, or any combination thereof.

3. The method of claim 1 , wherein the transmitting the SL-PRS is associated with a priority status or an on-demand request, and the SL-PRS monitoring capability is discontinuous in a DRX mode.

4. A user equipment (UE), Memory and at least one transceiver; at least one processor communicatively coupled to the memory and the at least one transceiver; wherein the at least one processor receiving, via the at least one transceiver, configuration information associated with a location-based discontinuous reception (DRX) mode; obtaining a geographical location of the UE; a user equipment (UE) configured to transmit, via the at least one transceiver, a sidelink positioning reference signal (SL-PRS) based on the location while in an inactive state of the location-based DRX mode;

5. The UE of claim 4 , wherein the location of the UE is based on satellite signals, cellular signals, Wi-Fi signals, sensor information, or any combination thereof.

6. The UE of claim 4 , wherein the UE transmitting the SL-PRS is associated with a priority status or an on-demand request, and the SL-PRS monitoring capability is discontinuous in DRX mode.

7. A non-transitory computer-readable medium having stored thereon computer-executable instructions that, when executed by a user equipment (UE), cause the UE to: receiving configuration information associated with a location-based discontinuous reception (DRX) mode; obtaining the location of the UE; 12. A non-transitory computer-readable medium for causing transmission of a sidelink positioning reference signal (SL-PRS) based on the location while in an inactive state of the location-based DRX mode.

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