Method and apparatus for sidelink positioning of mobile devices

Abstract

Sidelink positioning of multiple UEs can be performed using the Sidelink (SL) Positioning Protocol (SLPP) in either session mode or sessionless mode. In session mode, one UE of the multiple UEs can discover other UEs, determine a session for SLPP, indicate the session to the other UEs, and exchange multiple SLPP messages with the other UEs, where the SLPP messages are part of the session and enable sidelink positioning. In sessionless mode, the UE may not discover some or all of the other UEs of the multiple UEs and may exchange multiple SLPP messages with the other UEs, where the SLPP messages are not part of the session but enable sidelink positioning. The two modes can each be applied to SL positioning using SL PRS signals, as well as WiFi, UWB, and GNSS signals.

Description

[Technical Field]

[0001] Related Applications

[0001] This application claims the benefit of U.S. patent application Ser. No. 18 / 366,455, filed Aug. 7, 2023, entitled "SYSTEMS AND METHODS FOR MODES OF SIDELINK POSITIONING OF MOBILE DEVICES," and Ser. No. 18 / 366,455, filed Aug. 9, 2022, entitled "SYSTEMS AND METHODS FOR 5 TH This application claims the benefit of U.S. Provisional Patent Application No. 63 / 370,918, entitled "5G GENERATION (5G) SIDELINK POSITIONING," both of which are assigned to the assignee of the present application and are incorporated herein by reference in their entireties. [Background technology]

[0002] 1. Field of Disclosure

[0002] The present disclosure relates generally to the field of wireless communications, and more specifically to determining the location of one or more user equipments (UEs) using radio frequency (RF) signals transmitted between UEs based on sidelink (SL) communications.

[0003] 2. Description of Related Technology Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, positioning, and broadcasting. Typical wireless communication systems may utilize multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple-access systems include fourth-generation (4G) systems, such as Long-Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth-generation (5G) systems, sometimes referred to as New Radio (NR) systems.

[0004] In some examples, a wireless multiple-access communication system may include several base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipment (UEs). A base station may communicate with a set of UEs on a downlink channel (e.g., for transmissions from the base station to the UEs) and an uplink channel (e.g., for transmissions from the UEs to the base station). In addition, the UEs may communicate directly with each other using sidelink channels.

[0005]

[0005] The location of a UE may be useful or necessary for several applications, including emergency calls, navigation, direction finding, asset tracking, and Internet services. For example, in a cellular network, a base station may send a downlink reference signal using which positioning measurements are obtained by the UE, and / or the UE may send an uplink reference signal using which positioning measurements are obtained by the base station. The UE may calculate an estimate of its own location using the positioning measurements in UE-based positioning, or may send the positioning measurements to a network entity, e.g., a location server, which may calculate the location of the UE based on the positioning measurements in UE-assisted positioning.

[0006] There are several other applications where the location of one or more UEs may be required and where traditional UE-based and UE-assisted positioning may not be very useful. Examples of such applications include vehicle-to-everything (V2X) communication and coordination, public safety first responder scenarios, and control and coordination of automated environments such as factories and warehouses. In these applications, it may be more effective for UEs to communicate using sidelink signaling and for UEs to be located using sidelink-related positioning measurements and / or sidelink-related control signaling. Furthermore, procedures may be established to enable two or more UEs to perform positioning (including ranging) using sidelink communications. However, many aspects of these sidelink-based procedures have not yet been formalized. Summary of the Invention

[0007] Sidelink positioning of multiple UEs can be performed using the Sidelink (SL) Positioning Protocol (SLPP) in either session mode or sessionless mode. In session mode, one UE of multiple UEs can discover other UEs, determine a session for SLPP, indicate the session to the other UEs, and exchange multiple SLPP messages with the other UEs, where the SLPP messages are part of the session and enable sidelink positioning. In sessionless mode, the UE may not discover some or all of the other UEs of the multiple UEs and may exchange multiple SLPP messages with the other UEs, where the SLPP messages are not part of the session but enable sidelink positioning. The two modes can each be applied to SL positioning using SL PRS signals, as well as WiFi, UWB, and GNSS signals.

[0008]

[0008] An exemplary method performed by a user equipment (UE) for sidelink positioning of a plurality of UEs including the UE, the method including: determining a session for a sidelink positioning protocol (SLPP) for the plurality of UEs, the session being indicated to each UE among the plurality of UEs; and exchanging a plurality of SLPP messages with other UEs among the plurality of UEs, the SLPP messages being part of the session, the SLPP messages enabling sidelink positioning.

[0009]

[0009] An exemplary method performed by a user equipment (UE) for sidelink positioning of a plurality of UEs including the UE, the method including: determining to perform sidelink positioning of the plurality of UEs, where there is no discovery between the UE and at least some of the other UEs among the plurality of UEs; and exchanging, using broadcast or groupcast, a plurality of SLPP messages with the other UEs among the plurality of UEs, where the SLPP messages are not part of a session and the SLPP messages enable sidelink positioning.

[0010] An exemplary UE for sidelink positioning of a plurality of UEs including a UE comprises a transceiver, a memory, and one or more processors communicatively coupled to the transceiver and the memory. The one or more processors can be configured to: determine a Sidelink Positioning Protocol (SLPP) session for the plurality of UEs, the session indicated to each UE of the plurality of UEs; and exchange a plurality of SLPP messages with other UEs of the plurality of UEs, the SLPP messages being part of the session, the SLPP messages enabling sidelink positioning.

[0011] An exemplary UE for sidelink positioning of a plurality of UEs, including a UE, comprises a transceiver, a memory, and one or more processors communicatively coupled to the transceiver and the memory. The one or more processors may be configured to: determine to perform sidelink positioning of the plurality of UEs, where there is no discovery between the UE and at least some of the other UEs of the plurality of UEs; and exchange, using broadcast or groupcast, a plurality of SLPP messages with the other UEs of the plurality of UEs, where the SLPP messages are not part of a session, and the SLPP messages enable the sidelink positioning.

[0012]

[0012] This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used alone to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification, any or all drawings, and appropriate portions of each claim of this disclosure. The above, together with other features and examples, are described in more detail below in the following specification, claims, and accompanying drawings. [Brief explanation of the drawings]

[0013] [Figure 1]

[0013] The architecture of a communication system including several UEs, a Radio Access Network (RAN) and a 5G Core Network (5GC) is shown. [Figure 2]

[0014] 1 shows a communication system architecture for network-supported sidelink positioning. [Figure 3]

[0015] 10 is a signal flow illustrating signaling between a UE and a location server for network-supported sidelink positioning. [Figure 4A]

[0016] FIG. 1 is a block diagram illustrating an implementation of a sidelink positioning protocol (SLPP) message structure. [Figure 4B] FIG. 1 is a block diagram illustrating an implementation of a sidelink positioning protocol (SLPP) message structure. [Figure 5]

[0017] 1 is a signal flow illustrating signaling between a pair of UEs for pair-wise sidelink positioning. [Figure 6A]

[0018] 10 is a signal flow illustrating signaling between UEs for sidelink positioning capability exchange, including the exchange of capabilities, resources, and service requirements. [Figure 6B]

[0019] 1 is a signal flow illustrating signaling between UEs for positioning signal configuration and confirmation exchange. [Figure 6C]

[0020] 1 is a signal flow illustrating signaling between UEs for measurement exchange. [Figure 7]

[0021] 10 is a signal flow illustrating signaling for group operation of sidelink positioning for multiple UEs. [Figure 8]

[0022] 1 is a signal flow illustrating signaling between UEs for pairwise mode sidelink positioning according to one embodiment. [Figure 9]

[0023] 1 is a signal flow illustrating signaling between UEs for pairwise mode sidelink positioning according to one embodiment. [Figure 10]

[0024] FIG. 1 illustrates an implementation of a group mode sidelink positioning system, according to one embodiment. [Figure 11]

[0025] 1 is a signal flow illustrating signaling between UEs for group mode sidelink positioning using an SLPP session according to one embodiment. [Figure 12]

[0026] 1 is a signal flow illustrating signaling between UEs for group mode sidelink positioning using an SLPP session according to one embodiment. [Figure 13]

[0027] 10 is a signal flow illustrating signaling between UEs to initiate a session for group mode sidelink positioning, according to one embodiment. [Figure 14]

[0028] 10 is a signal flow illustrating signaling between UEs for group session operation of sidelink positioning according to one embodiment; [Figure 15]

[0029] 10 is a signal flow illustrating signaling between UEs for modifying a sidelink positioning session according to one embodiment; [Figure 16]

[0030] 1 is a signal flow illustrating the signal flow between UEs for participating in a session for group mode sidelink positioning, according to one embodiment. [Figure 17]

[0031] 10 is a signal flow illustrating signaling between UEs for leaving a session for group mode sidelink positioning, according to one embodiment. [Figure 18]

[0032] 10 is a signal flow illustrating signaling between UEs for terminating a session for group mode sidelink positioning, according to one embodiment. [Figure 19]

[0033] 1 is a signal flow illustrating signaling between UEs for session-less mode sidelink positioning according to one embodiment. [Figure 20]

[0034] FIG. 10 is a flow diagram of a method for supporting sidelink positioning for multiple UEs according to an embodiment. [Figure 21]

[0035] FIG. 10 is a flow diagram of a method for supporting sidelink positioning of multiple UEs using SLPP sessions according to an embodiment; [Figure 22]

[0036] FIG. 10 is a flow diagram of a method for supporting sidelink positioning for multiple UEs in session-less mode according to an embodiment; [Figure 23]

[0037] FIG. 1 is a block diagram of an embodiment of a UE that can be utilized in the embodiments described herein. [Figure 24]

[0038] FIG. 1 shows a schematic block diagram illustrating certain example features of a UE configured to support sidelink positioning as described herein.

[0014]

[0039] According to some example implementations, like reference numerals in various figures refer to like elements. Additionally, multiple instances of an element may be indicated by the first numeral of that element followed by a letter or hyphen and a second numeral. For example, multiple instances of element 110 may be indicated as 110-1, 110-2, 110-3, etc., or as 110a, 110b, 110c, etc. When referring to such an element using only the first numeral, it should be understood to refer to any instance of that element (e.g., element 110 in the previous example refers to elements 110-1, 110-2, and 110-3, or elements 110a, 110b, and 110c). DETAILED DESCRIPTION OF THE INVENTION

[0015]

[0040] Techniques and apparatus for supporting sidelink positioning (SL) between UEs are described herein. The Sidelink Positioning Protocol (SLPP) can be used to support sidelink positioning of UEs in pairwise positioning (referred to as pairwise mode), group operation (referred to as group mode), and network-supported SLPP.

[0016]

[0041] The description may refer to sequences of actions to be performed by, for example, elements of a computing device. The various actions described herein may be performed by specific circuitry (e.g., an application specific integrated circuit (ASIC)), by program instructions executed by one or more processors, or a combination of both. The sequences of actions described herein may be embodied in a non-transitory computer-readable medium having stored thereon a corresponding set of computer instructions that, when executed, cause an associated processor to perform the functions described herein. Accordingly, the various aspects described herein may be embodied in several different forms, all of which are within the scope of the present disclosure, including the claimed subject matter.

[0017]

[0042] The terms “user equipment” (UE) and “base station” as used herein are not specific to or otherwise limited to any particular Radio Access Technology (RAT) unless otherwise specified. Generally, such a UE may be any wireless communication device (e.g., a mobile phone, a router, a tablet computer, a laptop computer, a tracking device, an Internet of Things (IoT) device, an Industrial IoT (IIoT) device, an In-Vehicle System (IVS), etc.) used to communicate over a wireless communication network. A UE may be mobile or may be stationary (e.g., at certain times or all the time) and may communicate with a Radio Access Network (RAN). For example, as used herein, a UE may be an infrastructure node such as a roadside unit (RSU), a Positioning Reference Unit (PRU), etc. As used herein, the term "UE" may be referred to interchangeably as an "access terminal" or "AT," a "client device," a "wireless device," a "subscriber device," a "subscriber terminal," a "subscriber station," a "user terminal" or UT, a "mobile terminal," a "mobile station," a "mobile device," an RSU, a PRU, an IVS, or variations thereof. Generally, a UE can communicate with a core network via a RAN, through which the UE can be connected to external networks such as the Internet and to other UEs. Of course, other mechanisms for a UE to connect to the core network and / or the Internet are contemplated, such as via a wired access network, a Wi-Fi network (e.g., based on IEEE 802.11, etc.), etc.

[0018]

[0043] Depending on the network in which the base station is deployed, the base station may operate according to one of several RATs while communicating with UEs and may alternatively be referred to as an Access Point (AP), network node, Node B, evolved Node B (eNB), general Node B (gNodeB, gNB), etc. Additionally, in some systems, the base station may simply provide edge node signaling functionality, while in other systems the base station may provide additional control and / or network management functionality.

[0019]

[0044] A UE may be embodied by any of several types of devices, including, but not limited to, a printed circuit (PC) card, a compact flash device, an external or internal modem, a wireless or wireline phone, a smartphone, a tablet, a tracking device, an asset tag, etc. A communication link through which a UE can transmit signals to a RAN is called an uplink channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). A communication link through which a RAN can send signals to a UE is called a downlink channel or a forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). A communication link through which a UE can send signals to other UEs is called a sidelink channel. As used herein, the term traffic channel (TCH) can refer to either an uplink / reverse traffic channel or a downlink / forward or sidelink traffic channel.

[0020]

[0045] The terms "cell" or "sector" as used herein may correspond to one of multiple cells of a base station or to the base station itself, depending on the context. The term "cell" may refer to a logical communication entity used for communication with a base station (e.g., via a carrier) and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID)) to distinguish between adjacent cells operating over the same or different carriers. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., machine-type communication (MTC), narrowband Internet-of-Things (NB-IoT), enhanced mobile broadband (eMBB), or others) that may provide access to different types of devices. In some examples, the term "cell" may refer to a portion (e.g., a sector) of a geographic coverage area over which the logical entity operates.

[0021]

[0046] As used herein, an "RF signal" includes electromagnetic waves that transport information through space between a transmitter (or transmitting device) and a receiver (or receiving device). As used herein, a transmitter may transmit a single "RF signal" or multiple "RF signals" to a receiver. However, a receiver may receive multiple "RF signals" corresponding to each transmitted RF signal due to the propagation characteristics of RF signals through multiple channels or paths.

[0022]

[0047] Additionally, unless otherwise specified, references to "reference signals," "positioning reference signals," "reference signals for positioning," etc. may be used to refer to signals used for positioning of user equipment (UE) in 5G New Radio (NR) networks, 4G (LTE) networks, or future (e.g., 6G) networks. As described in more detail herein, such signals may include any of a variety of signal types, but may not necessarily be limited to positioning reference signals (PRS) as defined in the relevant wireless standards.

[0023]

[0048] Additionally, unless otherwise specified, the term "positioning" as used herein may include absolute location determination, relative location determination, ranging, or a combination thereof. Accordingly, positioning measurements described herein may include range measurements. Such positioning may include and / or be based on timing, angle, phase, or power measurements, or a combination thereof (which may include RF sensing measurements), for purposes of location or sensing services.

[0024]

[0049] As noted above, SL-based signaling between two or more UEs can potentially be used to perform positioning (including ranging) of at least one of the UEs. However, many procedural aspects of such positioning have not yet been defined or formalized. Embodiments herein address these and other issues by providing message types, transactions, procedures, and positioning modes that may be used in a protocol for SL-based positioning, referred to herein as the SL Positioning Protocol or SLPP. According to some aspects, advantages may include extending positioning range and capabilities beyond that of traditional LPP positioning of a UE, in which the UE exchanges uplink and / or downlink signals with one or more base stations.

[0025]

[0050] FIG. 1 illustrates an example of a communication system 100 including a first UE 105A, a second UE 105B, a third UE 105C, a radio access network (RAN) 135, here a fifth generation (5G) next generation (NG) RAN (NG-RAN), and a 5G core network (5GC) 140. The 5GC 140 may be, for example, a public land mobile network (PLMN). The UEs 105A, 105B, and 105C may be individually referred to herein as UEs 105 or collectively referred to as UEs 105. The UEs 105 may be, for example, IoT devices, location tracking devices, mobile phones, vehicles, on-board units (OBUs), or other similar types of devices. The UEs 105 may additionally be considered RSUs or PRUs. The 5G network may also be referred to as a New Radio (NR) network, the NG-RAN 135 may also be referred to as a 5G RAN or an NR RAN, and the 5GC 140 may also be referred to as an NG Core network (NGC). The RAN 135 may be another type of RAN, such as a 3G RAN, a 4G Long Term Evolution (LTE) RAN, etc.The communication system 100 may utilize a fleet of satellite vehicles (SVs) 190 that may support a satellite positioning system (SPS) (e.g., Global Navigation Satellite System (GNSS)), such as the Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), Galileo, or Beidou, or some other local or regional SPS, such as the Indian Regional Navigational Satellite System (IRNSS), the European Geostationary Navigation Overlay Service (EGNOS), or the Wide Area Augmentation System (WAAS). In some embodiments, the UE 105 may communicate with a RAN node (e.g., gNB 110) or a 5GC 140 node via the SV 190 and an earth station (not shown in FIG. 1 ), in which case the UE 105 may not communicate directly with the RAN node but only via the SV 190. This may be used to increase the coverage and / or capacity of the NG-RAN 135. Additional components of the communications system 100 are described below. The communications system 100 may include additional or alternative components.

[0026]

[0051] 1, the NG-RAN 135 includes NR NodeBs (gNBs) 110a, 110b, and a next generation eNodeB (ng-eNB) 114, and the 5GC 140 includes an Access and Mobility Management Function (AMF) 115, a Session Management Function (SMF) 117, a Location Management Function (LMF) 120, a Gateway Mobile Location Center (GMLC) 125, a User Plane Function (UPF) 118, and a Secure User Plane Location (SUPL) Location Platform (SLP) 119. The gNBs 110a, 110b, and the ng-eNB 114 are communicatively coupled to each other and configured to each communicate wirelessly bidirectionally with the UE 105, and are communicatively coupled to and configured to each communicate bidirectionally with the AMF 115 and the UPF 118. The gNBs 110a, 110b, and ng-eNB 114 may be referred to as base stations (BSs) or RAN nodes. The AMF 115, SMF 117, LMF 120, and GMLC 125 are communicatively coupled to each other, and the GMLC 125 is communicatively coupled to an external client 130. The AMF 115, SMF 117, UPF 118, and SLP 119 are communicatively coupled to each other, and the SLP 119 is communicatively coupled to an external client 130. According to some embodiments, the server 121, the Internet 122, and the server 123 may be communicatively coupled to the UPF 118 to facilitate SL positioning. The SMF 117 may further serve as an initial point of contact for a Service Control Function (SCF) (not shown), which creates, controls, and deletes media sessions.The base stations 110a, 110b, 114 may be macrocells (e.g., high-power cellular base stations), or small cells (e.g., low-power cellular base stations), or access points (e.g., short-range base stations configured to communicate with short-range technologies such as Wi-Fi, Wi-Fi Direct (WiFi-D), BLUETOOTH, Bluetooth-low energy (BLE), ZIGBEE, etc.). One or more of the base stations 110a, 110b, 114 may be configured to communicate with the UE 105 over multiple carriers. Each of the base stations 110a, 110b, 114 may provide communication coverage for a respective geographic area, e.g., a cell. Each cell may be partitioned into multiple sectors depending on the base station antenna.

[0027]

[0052] 1 provides a generalized illustration of various components, any or all of which may be utilized as appropriate, and each of which may be duplicated or omitted as desired. In particular, while only the UE 105 is illustrated, many UEs (e.g., hundreds, thousands, millions, etc.) may be utilized in the communications system 100. Similarly, the communications system 100 may include many more (or fewer) SVs (i.e., more or fewer than the four SVs 190 shown), gNBs 110a, 110b, ng-eNB 114, AMF 115, external clients 130, and / or other components. The connections shown connecting the various components in the communications system 100 include data and signaling connections, which may include additional (intermediate) components, direct or indirect physical and / or wireless connections, and / or additional networks. Furthermore, components may be rearranged, combined, separated, substituted, and / or omitted depending on the desired functionality.

[0028]

[0053] 1 illustrates a 5G-based network. While FIG. 1 illustrates a 5G-based network, similar network implementations and configurations may be used for other communication technologies such as 3G, Long Term Evolution (LTE), future 6G, etc. Implementations described herein (whether for 5G technology and / or for one or more other communication technologies and / or protocols) may be used to transmit (or broadcast) directional synchronization signals, receive and measure the directional signals at a UE (e.g., the UE 105) or base station 110a, 110b, 114, and / or provide location assistance to the UE 105 (via the LMF 120 or SLP 119 or other location server), and / or calculate the location of one or both of the UEs 105 at a location-enabled device such as the UE 105, base station 110a, 110b, LMF 120, or SLP 119 based on measurements received at the UE 105 or base station 110a, 110b, 114 of such directionally transmitted signals. The GMLC 125, LMF 120, AMF 115, SMF 117, UPF 118, SLP 119, ng-eNB (eNodeB) 114, and gNBs (gNodeBs) 110a, 110b are examples and may be replaced by or include various other entities, including location server functionality and / or base station functionality, in various embodiments.

[0029]

[0054] The communications system 100 is capable of wireless communications in that components of the system 100 may communicate with one another (at least sometimes using wireless connections) directly or indirectly, e.g., via the base stations 110a, 110b, 114 and / or the network 140 (and / or one or more other devices, not shown, such as one or more other base transceiver stations). In the case of indirect communications, communications may be altered during transmission from one entity to another, e.g., to alter header information of data packets, to change formatting, etc. The UE 105 may include multiple UEs and may be a mobile wireless communications device, but may communicate wirelessly and via wired connections. The UE 105 may be any of a variety of devices, e.g., a smartphone, a tablet computer, a vehicle-based device, etc., although these are merely examples and other configurations of UEs may be used, as the UE 105 is not required to be any of these configurations. Other UEs may include wearable devices (e.g., a smart watch, smart jewelry, smart glasses, or a headset, etc.). Still other UEs, whether currently existing or developed in the future, may be used. Additionally, other wireless devices (whether mobile or not) may be implemented within system 100 and may communicate with each other and / or with UE 105, base stations 110a, 110b, 114, core network 140, and / or external client 130. For example, such other devices may include IoT or IIoT devices, medical devices, home entertainment and / or automation devices, etc. Core network 140 may communicate with external client 130, server 123, or server 121 (e.g., each of which may be a computer system) to, for example, enable external client 130, server 123, or server 121 to request and / or receive location information regarding UE 105 (e.g., via GMLC 125, SLP 119, or UPF 118).

[0030]

[0055] The UE 105 or other device may be configured to communicate in different networks and / or for different purposes and / or using different technologies (e.g., 5G, Wi-Fi (also called WiFi) communications, multiple frequencies of Wi-Fi communications, satellite positioning, satellite communications, one or more types of communications (e.g., GSM (Global System for Mobile Communications), CDMA (Code Division Multiple Access), LTE (Long Term Evolution), V2X (e.g., V2P (Vehicle-to-Pedestrian), V2I (Vehicle-to-Infrastructure), V2V (Vehicle-to-Vehicle), etc.), IEEE 802.11p, etc.). V2X communications may be cellular (Cellular-V2X, C-V2X) and / or Wi-Fi (e.g., DSRC (Dedicated Short-Range Remote Control)). The system 100 may be a dedicated short-range connection. The system 100 may support operation on multiple carriers (waveform signals at different frequencies). A multi-carrier transmitter can simultaneously transmit modulated signals on multiple carriers. Each modulated signal may be a Code Division Multiple Access (CDMA) signal, a Time Division Multiple Access (TDMA) signal, an Orthogonal Frequency Division Multiple Access (OFDMA) signal, a Single-Carrier Frequency Division Multiple Access (SC-FDMA) signal, etc. Each modulated signal may be transmitted on a different carrier and may carry pilot, overhead information, data, etc.The UEs 105 may communicate with each other via UE-to-UE sidelink (SL) communication by transmitting on one or more sidelink channels, such as a physical sidelink synchronization channel (PSSCH), a physical sidelink broadcast channel (PSBCH), a physical sidelink control channel (PSCCH), a synchronization signal block (SSB), a sidelink channel state information reference signal (SL-CSIRS), a physical sidelink feedback channel (PSFCH), a sidelink positioning reference signal (SL PRS), or a sidelink sounding reference signal (SL-SRS).

[0031]

[0056] The UE 105 may include and / or be referred to as a device, a mobile device, a wireless device, a mobile terminal, a terminal, a mobile station (MS), a Secure User Plane Location (SUPL) Enabled Terminal (SET), or some other name. Generally, although not necessarily, the UE 105 may support wireless communication using one or more radio access technologies (RATs), such as Global System for Mobile communications (GSM), Code Division Multiple Access (CDMA), Wideband CDMA (WCDMA), LTE, High Rate Packet Data (HRPD), IEEE 802.11 Wi-Fi (also referred to as Wi-Fi), Bluetooth (BT), Worldwide Interoperability for Microwave Access (WiMAX), 5G New Radio (NR) (e.g., using NG-RAN 135 and 5GC 140), future 6G, etc. The UE 105 may support wireless communications using, for example, a Wireless Local Area Network (WLAN), which may connect to other networks (e.g., the Internet) using a Digital Subscriber Line (DSL) or packet cable. Use of one or more of these RATs may enable the UE 105 to communicate with external clients 130, servers 121, and / or servers 123 (e.g., via elements of the 5GC 140 and possibly the Internet 122) and / or enable external clients 130, servers 121, and / or servers 123 to receive location-related information about the UE 105 (e.g., via the GMLC 125, the SLP 119, or the UPF 118).

[0032]

[0057] Each UE 105 may comprise a single entity or may comprise multiple entities, such as in a personal area network where a user may employ audio, video, and / or data I / O (input / output) devices and / or body sensors and a separate wireline or wireless modem. An estimate of the location of a UE, e.g., UE 105, may be referred to as a location, location estimate, location fix, fix, position, position estimate, or position fix, and may be geodetic and thus provide location coordinates (e.g., latitude and longitude) of the UE that may or may not include an altitude component (e.g., height above sea level, height or depth above ground, floor level, or basement level). Alternatively, the location of the UE may be expressed as a civic location (e.g., as a postal address or as a designation of some point or small area in a building, such as a particular room or floor). The location of the UE may be expressed as an area or volume (defined either geodetically or urbanically) within which the UE is expected to be located with some probability or confidence level (e.g., 67%, 95%, etc.). The location of a UE may be expressed as a relative location comprising, for example, a distance and a direction from a known location. The relative location may be expressed as relative coordinates (e.g., X, Y (and Z) coordinates) defined relative to some origin in the known location, which may be defined, for example, geodesically, in terms of cities, or by reference to a point, area, or volume shown on a map, floor plan, or building plan. In the description contained herein, use of the term location may include any of these variations unless otherwise indicated.

[0033]

[0058] When sidelink positioning is used, an absolute (e.g., global) or relative location of the UE may not always be obtained. Instead, location results may be obtained for the UE, which may include the range or distance between the UE and each of one or more other UEs, the direction from the UE to each of the one or more other UEs, the location of the UE relative to the locations of some other UEs, the locations of one or more other UEs relative to the UE's location, the velocity of the UE, and / or the velocity of each of the one or more other UEs. The velocity of a UE may be absolute (e.g., with respect to the Earth) or relative to some other UE and may be referred to as the "relative velocity." The relative velocity of UE B with respect to another UE A may include a "radial velocity" component, which may be equal to the rate of change of range from UE A to UE B, and a "lateral velocity" component, which may be orthogonal to the radial velocity component from the perspective of UE A and may be equal to the angular rate of change of the direction from UE A to UE B multiplied by the range from UE A to UE B. In the description contained herein, the use of the term "location result(s)" for sidelink positioning of a UE or group of UEs may include any of these variations, unless otherwise indicated.

[0034]

[0059] As used herein, the term "target UE" may refer to a UE for which a location result is desired. When a group of two or more UEs participates in SL positioning, only some of the group of UEs may be target UEs, since location results may already be known or may not be needed for other UEs. However, for generality, when describing the techniques described herein for positioning a group of UEs, all of the UEs may potentially be considered target UEs, since there may be little or no difference in how the techniques described herein are used for positioning.

[0035]

[0060] The UE 105 may be configured to communicate with other entities using one or more of a variety of technologies. The UE 105 may be configured to communicate with one or more other UEs (e.g., other UEs 105) via one or more device-to-device (D2D) peer-to-peer (P2P) links. A D2D P2P link may be an example of (or may be supported by) a sidelink and may be supported using any suitable D2D radio access technology (RAT), such as LTE Direct (LTE-D), Wi-Fi Direct (Wi-Fi D), Bluetooth, etc. One or more of a group of UEs utilizing D2D communication may be within the geographic coverage area of ​​a Transmission / Reception Point (TRP), such as one or more of the gNBs 110a, 110b, and / or ng-eNB 114. Other UEs in such a group may be outside such geographic coverage area or may otherwise be unable to receive transmissions from the base station. A group of UEs communicating via D2D communication may utilize a one-to-many (1:M) system in which each UE may transmit to other UEs in the group. The TRP may facilitate scheduling of resources for D2D communication. In other cases, D2D communication may be performed between UEs without the involvement of a TRP. One or more of a group of UEs utilizing D2D communication may be within a geographic coverage area of ​​a TRP. Other UEs in such a group may be outside such geographic coverage area or may otherwise be unable to receive transmissions from a base station. A group of UEs communicating via D2D communication may utilize a one-to-many (1:M) system in which each UE may transmit to other UEs in the group. The TRP may facilitate scheduling of resources for D2D communication. In other cases, D2D communication may be performed between UEs without the involvement of a TRP.

[0036]

[0061] The base stations (BSs) in the NG-RAN 135 shown in FIG. 1 include NR Node Bs referred to as gNBs 110a and 110b. The pair of gNBs 110a, 110b in the NG-RAN 135 may be connected to each other through one or more other gNBs. Access to the 5G network is provided to the UE 105 via wireless communication between the UE and one or more of the gNBs 110a, 110b, and the gNBs 110a, 110b may provide wireless communication access to the 5G Grid Control System 140 for UEs using 5G. In FIG. 1, the serving gNB for UE 105A is assumed to be gNB 110b, while the serving gNB for UE 105B is assumed to be gNB 110a; however, another gNB may serve as the serving gNB if the UE 105 moves to another location, or may serve as a secondary gNB to provide additional throughput and bandwidth to the UE 105, and the UEs 105 may share the same serving gNB.

[0037]

[0062] 1 may include the ng-eNB 114, also referred to as a next generation evolved Node B. The ng-eNB 114 may be connected to one or more of the gNBs 110a, 110b in the NG-RAN 135, possibly via one or more other gNBs and / or one or more other ng-eNBs. The ng-eNB 114 may provide LTE wireless access and / or evolved LTE (eLTE) wireless access to the UE 105. One or more of the gNBs 110a, 110b and / or ng-eNB 114 may be configured to function as positioning-only beacons that may transmit signals to assist in determining the location of the UE 105 but may not receive signals from the UE 105 or from other UEs.

[0038]

[0063] The base stations 110a, 110b, 114 may transmit one or more downlink reference signals, including positioning reference signal (PRS) transmissions. The PRS transmissions may be configured for a particular UE 105 to measure and report one or more reporting parameters (e.g., reporting quantities) associated with positioning and location information. The PRS transmissions and reporting parameter feedback may support various location services (e.g., navigation systems, emergency communications). In some examples, the reporting parameters augment one or more additional location systems (e.g., Global Positioning System (GPS) technology) supported by the UE 105.

[0039]

[0064] The base station 110a, 110b, 114 may configure PRS transmissions on one or more PRS resources of a channel. A PRS resource may span resource elements of multiple physical resource blocks (PRBs) within one or more OFDM symbols of a slot, depending on the configured number of ports. For example, a PRS resource may span one symbol of a slot and include one port for transmission. In any OFDM symbol, a PRS resource may occupy consecutive PRBs. In some examples, PRS transmissions may be mapped to consecutive OFDM symbols of a slot. In other examples, PRS transmissions may be mapped to interspersed OFDM symbols of a slot. Additionally, PRS transmissions may support frequency hopping within a PRB of a channel.

[0040]

[0065] One or more PRS resources may span several PRS resource sets according to the PRS resource configuration of the base station 110 a, 110 b, 114. The structure of one or more PRS resources, PRS resource sets, and PRS resource configurations within a PRS transmission may be referred to as a multi-level resource configuration. For example, the multi-level PRS resource configuration of the base station 110 a, 110 b, 114 may include multiple PRS resource sets, and each PRS resource set may include a set of PRS resources (such as a set of four PRS resources).

[0041]

[0066] The UE 105 may receive a PRS transmission via one or more PRS resources of the slot. The UE 105 may determine at least one reporting parameter for some of the PRS resources included in the transmission. The reporting parameter (which may include a reporting quantity) for each PRS resource may include one or more of a time of arrival (TOA), a reference signal time difference (RSTD), a reference signal receive power (RSRP), an angle, a PRS identification number, a receive-to-transmit difference (UE Rx-Tx), a signal-to-noise ratio (SNR), or a reference signal receive quality (RSRQ).

[0042]

[0067] Similarly, the UE 105 may be configured to transmit one or more additional uplink reference signals that can be received by the base stations 110a, 110b, 114 and used for positioning. For example, the UE 105 may transmit a sounding reference signal (SRS) for positioning. The base stations 110a, 110b, 114 that receive the uplink reference signals from the UE 105 may perform positioning measurements such as one or more of a time of arrival (TOA), a difference between receive and transmit (UE Rx-Tx), etc.

[0043]

[0068] A UE's position estimate may be determined using reference signals, such as PRS or SRS for positioning signals or other reference signals from one or more base stations 110a, 110b, 114 or the UE. Positioning methods such as downlink (DL) time difference of arrival (DL-TDOA), DL angle of departure (DL AOD), and enhanced cell ID (ECID) are positioning methods that may be used to estimate a UE's position using reference signals from base stations. For example, DL-TDOA relies on measuring reference signal time differences (RSTDs) between downlink (DL) signals received from a base station for a reference cell and DL signals received from base stations for one or more neighboring cells. DL signals from which RTSDs may be obtained comprise cell-specific reference signals (CRS) and positioning reference signals (PRS).

[0044]

[0069] Other positioning methods may use reference signals transmitted by the UE, including uplink-based positioning methods and downlink- and uplink-based positioning methods. For example, uplink-based positioning methods include, for example, UL Time Difference of Arrival (UL-TDOA), UL Angle of Arrival (UL AOA), and UL Relative Time of Arrival (UL-RTOA). Downlink- and uplink-based positioning methods include, for example, multi-cell round trip time (RTT) between the UE and one or more neighboring base stations. In addition, sidelink-based positioning may be used, in which the UE transmits and / or receives sidelink positioning reference signals that are measured and used for positioning.

[0045]

[0070] As noted, while FIG. 1 illustrates nodes configured to communicate according to 5G communication protocols, nodes configured to communicate according to other communication protocols, such as, for example, the LTE protocol or the IEEE 802.11x protocol, or future 6G protocols, may also be used. For example, in an Evolved Packet System (EPS) providing LTE wireless access to the UE 105, the RAN may include an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), which may include base stations including evolved Node Bs (eNBs). The core network for the EPS may comprise an Evolved Packet Core (EPC). The EPS may include the E-UTRAN plus the EPC, where in FIG. 1, the E-UTRAN corresponds to the NG-RAN 135 and the EPC corresponds to the 5GC 140.

[0046]

[0071] The gNBs 110a, 110b, and ng-eNB 114 may communicate with the AMF 115, which in turn communicates with the LMF 120 for positioning functions. The AMF 115 may support mobility of the UE 105, including cell changes and handovers, and may be responsible for supporting signaling connections to the UE 105 and possibly data and voice bearers for the UE 105. The LMF 120 may communicate directly or indirectly with the UE 105 or with the base stations 110a, 110b, 114, for example, via wireless communication. The LMF 120 may support positioning of the UE 105 when the UE 105 accesses the NG-RAN 135 and may support positioning procedures / methods such as Assisted GNSS (A-GNSS), Time Difference of Arrival (TDOA) (e.g., downlink (DL) TDOA or uplink (UL) TDOA), Real Time Kinematic (RTK), Precise Point Positioning (PPP), Differential GNSS (DGNSS), Extended Cell ID (E-CID), Angle of Arrival (AOA), Angle of Departure (AOD), and / or other positioning methods. The LMF 120 may process location service requests for the UE 105, for example, received from the AMF 115 or from the GMLC 125. The LMF 120 may be connected to the AMF 115 and / or to the GMLC 125. A node / system running LMF 120 may additionally or alternatively run other types of location support modules, such as an Enhanced Serving Mobile Location Center (E-SMLC) or a Secure User Plane Location (SUPL) Location Platform (SLP).At least a portion of the positioning functionality (including derivation of the UE's location) may be performed in the UE (e.g., using signal measurements obtained by the UE due to signals transmitted by wireless nodes such as the gNBs 110a, 110b and / or the ng-eNB 114 and / or assistance data provided to the UE by the LMF 120, for example). At least a portion of the positioning functionality (including derivation of the UE's location) may alternatively be performed in the LMF 120 (e.g., using signal measurements obtained by the gNBs 110a, 110b and / or the ng-eNB 114). The AMF 115 may act as a control node that handles signaling between the UE 105 and the core network 140 and provides quality of service (QoS) flow and session management. The AMF 115 may support the mobility of the UE 105, including cell changes and handovers, and may be responsible for supporting signaling connections to the UE 105.

[0047]

[0072] The GMLC 125 may support location requests for the UE 105 received from the external client 130 and may forward such location requests to the AMF 115 for forwarding by the AMF 115 to the LMF 120, or may forward the location request directly to the LMF 120. A location response (e.g., including a location estimate or sidelink location result for the UE 105) from the LMF 120 may be returned to the GMLC 125 either directly or via the AMF 115, which may then return a location response (e.g., including the location estimate or sidelink location result) to the external client 130. Although the GMLC 125 is shown connected to both the AMF 115 and the LMF 120, in some implementations, only one of these connections may be supported by the 5GC 140.

[0048]

[0073] The user plane function (UPF) 118 may support voice and data bearers for the UE 105 and enable voice and data access for the UE 105 to other networks, such as the Internet 122, and servers, such as server 121 and server 123. The UPF 118 may be connected to the gNB 110 and the ng-eNB 114. The functions of the UPF 118 may include external Protocol Data Unit (PDU) session points for interconnection to data networks, packet (e.g., Internet Protocol (IP)) routing and forwarding, the user plane portion of packet inspection and policy rule enforcement, Quality of Service (QoS) handling for the user plane, downlink packet buffering, and triggering of downlink data notifications. The UPF 118 may be connected to the SLP 119 to enable support for positioning of the UE 105 using SUPL. The SLP 119 may further be connected to or accessible by the external client 130.

[0049]

[0074] As shown, a session management function (SMF) 117 connects the AMF 115 and the UPF 118. The SMF 117 may have the ability to control both the local UPF and the central UPF within a PDU session. The SMF 117 may manage the establishment, modification, and release of PDU sessions for the UE 105, perform IP address allocation and management for the UE 105, act as a Dynamic Host Configuration Protocol (DHCP) server for the UE 105, and select and control the UPF 118 for the UE 105.

[0050]

[0075] 1, the LMF 120 may communicate with the gNBs 110a, 110b, and / or the ng-eNB 114 using the New Radio Position Protocol A (NRPPa), which may be defined in 3GPP Technical Specification (TS) 38.455. NRPPa messages may be transferred between the gNB 110a (or gNB 110b) and the LMF 120 and / or between the ng-eNB 114 and the LMF 120 via the AMF 115. As further shown in FIG. 1, the LMF 120 and the UE 105 may communicate using the LTE Positioning Protocol (LPP), which may be defined in 3GPP TS 37.355. Here, LPP messages may be transferred between the UE 105 and the LMF 120 via the AMF 115 and the serving gNB 110a, 110b, or serving ng-eNB 114 for the UE 105. For example, LPP messages may be transferred between the LMF 120 and the AMF 115 using service operations based on the Hypertext Transfer Protocol (HTTP), and may be transferred between the AMF 115 and the UE 105 using 5G Non-Access Stratum (NAS) protocols.

[0051]

[0076] The LPP protocol may be used to support positioning of the UE 105 using UE-assisted and / or UE-based positioning methods, such as A-GNSS, RTK, TDOA, AOA, AOD, and / or E-CID. The NRPPa protocol may be used to support positioning of the UE 105 using network-based positioning methods, such as E-CID (e.g., when used in conjunction with measurements obtained by the gNBs 110a, 110b, or ng-eNB 114), and / or may be used by the LMF 120 to obtain location-related information from the gNBs 110a, 110b, and / or ng-eNB 114, such as parameters defining directional synchronization signal (SS) transmissions from the gNBs 110a, 110b, and / or ng-eNB 114. While the LMF 120 is shown in FIG. 1 as being located in the core network 140, it may also be outside the core network 140, e.g., in the NG-RAN. For example, the LMF120 may be co-located or integrated with the gNB, or may be located remotely from the gNB, and may be configured to communicate directly or indirectly with the gNB.

[0052]

[0077] In a UE-assisted positioning method, a UE, e.g., UE 105A or UE 105B, may obtain location measurements and send the measurements to a location server (e.g., LMF 120) for calculation of a location estimate for the UE. For example, the location measurements may include one or more of a Received Signal Strength Indication (RSSI), a Round Trip Signal Propagation Time (RTT), a Reference Signal Time Difference (RSTD), a Reference Signal Received Power (RSRP) and / or a Reference Signal Received Quality (RSRQ), an AOA, and an AOD for the gNB 110a, 110b, the ng-eNB 114, and / or a WLAN AP. The location measurements may also or instead include measurements of GNSS pseudorange, code phase, and / or carrier phase for SV 190-193.

[0053]

[0078] In a UE-based positioning method, a UE, for example, UE 105A or UE 105B, may obtain location measurements (which may, for example, be the same as or similar to location measurements for a UE-assisted positioning method) and may calculate the location of the UE (e.g., with the help of assistance data received from a location server such as LMF 120 or broadcast by gNB 110a, 110b, ng-eNB 114, or other base station or AP).

[0054]

[0079] In a network-based positioning method, one or more base stations (e.g., gNBs 110a, 110b, and / or ng-eNB 114) may obtain location measurements (e.g., RSSI, RTT, RSRP, RSRQ, AOA, AOD, or Time of Arrival (ToA) measurements for signals transmitted by a UE, e.g., UE 105A or UE 105B) and / or may receive measurements obtained by the UE. One or more base stations or APs may send the measurements to a location server (e.g., LMF 120) for calculation of a location estimate for the UE.

[0055]

[0080] As mentioned, although the communications system 100 is described with respect to 5G technology, the communications system 100 may be implemented to support other communications technologies, such as GSM, WCDMA, LTE, etc., used to support and interact with mobile devices such as the UEs 105 (e.g., to perform voice, data, positioning, and other functions). For example, in an EPS, the NG-RAN 135 may be replaced with an E-UTRAN including an eNB, and the 5GC 140 may be replaced with an EPC including a Mobility Management Entity (MME) in place of the AMF 115, an E-SMLC in place of the LMF 120, and a GMLC, which may be similar to the GMLC 125.

[0056]

[0081] Positioning for a UE in a wireless network, such as the communication system 100 shown in FIG. 1, typically uses the Uu interface, i.e., the air interface between the UE 105 and the radio access network, for DL ​​PRS and / or UL PRS. Positioning for a UE may also, or instead, use sidelink PRS (SL PRS), which may be a specific sidelink-defined reference signal for positioning, or may reuse Uu PRS, e.g., UL PRS, sometimes referred to as Sounding Reference Signals for positioning (SRSPos), or other reference signals may be transmitted in the sidelink channel. Sidelink positioning may extend UE positioning by providing additional transmitting (or receiving) nodes. A UE, such as UE 105B, with a known location may be used to support the position determination of another target UE, such as UE 105A, and UE 105B may be referred to as an anchor node.

[0057]

[0082] Using the sidelink positioning method, the UE 105A may transmit, for example, a sidelink PRS or sidelink SRS signal to be received and measured by another UE 105B. Additionally or alternatively, the UE 105B may transmit, for example, a sidelink PRS or sidelink SRS signal to be received and measured by the UE 105A. The sidelink PRS may be similar to the PRS (e.g., DL PRS) transmitted by the gNB 110, for example, as described above. The sidelink SRS may be similar to the SRS (e.g., uplink) transmitted by the UE 105 for measurement by the gNB 110, for example, as described above. The SL PRS may be transmitted over a separate, short period (e.g., approximately 1 millisecond in duration) called an "SL PRS occasion" or "SL PRS positioning occasion." Measurements of SL PRS or SL SRS signals may include reception to transmission time difference (Rx-Tx), time of arrival (TOA), reference signal received power (RSRP), reference signal received quality (RSRQ), angle of arrival (AOA), and reference signal time difference (RSTD). SL positioning methods may include SL round trip signal propagation time (RTT) (also called ranging), SL AOA, and SL AOD.

[0058]

[0083] In some scenarios, a group of UEs 105 may support SL positioning. In this case, one UE in the group (e.g., UE 105A) may transmit an SL PRS or SL SRS signal that can be measured by some or all of the other UEs 105 in the group (e.g., UEs 105B and 105C). Some or all of the other UEs 105 in the group may also each transmit an SL PRS or SL SRS signal that can be measured by some or all of the other UEs 105 in the group that are different from the UE 105 transmitting the UL PRS or ULS SRS (e.g., each UE 105 transmits the SL SRS or SL PRS at one or more times that are different from the times at which the other UEs 105 in the group transmit the SL PRS or SL SRS). Measurements made by the UE 105 that are applicable to the transmission of the SL PRS or SL SRS by the group of UEs 105 may include Rx-Tx, TOA, RSTD, AOA, RSRP, and RSRQ. Positioning methods supported by these measurements may include sidelink RTT (e.g., ranging), sidelink AOA, sidelink AOD, and sidelink TDOA (SL-TDOA). Based on the measurements and the positioning method, each UE 105 may determine a location result for itself and / or one or more other UEs 105 in the group. As mentioned above, the location result for a UE 105 may include the range or distance between the UE 105 and each of the one or more other UEs 105 in the group, the direction from the UE 105 to each of the one or more other UEs 105 in the group, the direction from each of the one or more other UEs 105 in the group to the UE 105, the location of the UE 105 relative to the locations of any other UEs 105 in the group, the location of the UE 105 relative to some other known location, the absolute location of the UE 105, the velocity of the UE 105, or the velocity of the UE 105 relative to some other UEs 105.

[0059]

[0084] Sidelink positioning can be used for positioning a UE independent of the core network (e.g., 5GC 140) or the serving PLMN. One example implementation of sidelink positioning can be found in vehicular communication systems such as V2X, which can be used for safety-related applications such as safety warnings, traffic congestion (e.g., automated traffic control), and cooperative or automated vehicle steering. One aspect of sidelink positioning that may require a standardization solution is the Sidelink Positioning Protocol (SLPP), which can be used between a UE and a location server, including between an RSU and a UE. SLPP can support sidelink positioning, for example, between a UE, an RSU, and a PRU with network access independence. SLPP can provide support for sidelink positioning for pairs of UEs (e.g., ranging), groups of UEs (V2X), and UEs that are members of multiple different groups. By way of example, SLPP may provide support for various positioning techniques currently standardized for UE-based and UE-assisted support by location servers (e.g., LMF 120), such as PRS RTT, AOA, Differential AOA (DAOA), AOD, and Differential AOD (DAOD), but may also enable support for other PRS and SRS-based positioning methods, as well as non-PRS methods such as RTK later. By allowing for the addition of new capabilities and methods later, SLPP may avoid the need to define a new positioning protocol separate and distinct from SLPP. By way of example, additional positioning methods that may later be included in SLPP may include RTK, Wi-Fi, Ultra-Wideband (UWB), and BT positioning methods.

[0060]

[0085] SLPP may initially enable direct sidelink operation (UEs communicate and coordinate positioning by exchanging SLPP messages using sidelink signaling) and may later be extended to sidelink operation via relays and network-mediated operation, where UEs may exchange SLPP messages via the network or via intermediate relay UEs. For example, this may be used to coordinate positioning of two vehicles on a collision course at a corner where direct SL signaling between the two vehicles is not possible. Therefore, SLPP may initially define support for SL PRS-based positioning in a general manner to simplify later extension to support other positioning methods. For example, SLPP may define general SLPP messages similar to the general LPP messages defined for LPP in 3GPP TS 37.355. SLPP may support distinct positioning methods (e.g., SL PRS RTT, SL PRS AOA, SL PRS AOD) using common procedures and common parameters, where feasible. SLPP may define procedures that can be reused for multiple positioning methods and is not limited to just one or a few positioning methods. SLPP may be enabled to be forwarded and used by various entities, such as UEs, RSUs, PRUs, and location servers such as LMF and SUPL SLPs. Location server (e.g., LMF and SUPL SLP) applications may forward SLPP messages within LPP messages to enable UE-assisted positioning by the LMF or SUPL SLP. Alternatively, location server (e.g., LMF and SUPL SLP) applications may forward SLPP messages that are not associated with LPP messages to enable UE-assisted positioning by the LMF or SUPL SLP. SLPP may further support relative (local) and global positioning.

[0061]

[0086] FIG. 2 illustrates, by way of example, the architecture of a communication system 200 capable of network-supported sidelink positioning. As illustrated in FIG. 2, several UEs may be combined into the same group 210 for sidelink positioning. Within the group 210, there may be various subgroups of UEs. For example, the group 210 of UEs may include a first subgroup 212 of UEs served by a first network (PLMN1 140a), a second subgroup 214 of UEs served by a second (different) network (PLMN2 140b), and a third subgroup 216 of UEs that are out of coverage and not served by either network. One or more of the UEs served by the network, e.g., the UEs in the subgroup 212 served by PLMN1 140a or the UEs in the subgroup 214 served by PLMN2 140b, may include RSUs.

[0062]

[0087] Location servers in the serving networks, e.g., LMF1 120a, SUPL SLP1 119a, or Server 1 121a in serving PLMN1 140a, LMF2 120b, SUPL SLP2 119b, or Server 2 121b in serving PLMN2 140b, and Server 3 123 (which communicates to the UEs via PLMN1 140a and / or PLMN2 140b), may support some or all UEs in a group served by the network (PLMN), e.g., subgroups 212 and 214, respectively. As shown, the location servers may support the UEs by communicating with the UEs using "LPP / SLPP," which refers to communicating using LPP, SLPP, embedding SLPP in LPP, or a combination thereof. For example, LMF1 120a and LMF2 120b may embed SLPP in the LPP while supporting UEs in subgroups 212 and 214, respectively (e.g., each SLPP message transferred between a UE and LMF1 120a or LMF2 120b may be embedded in one LPP message, and one LPP message may contain one or more embedded SLPP messages). Similarly, SUPL SLP1 119a and SUPL SLP2 119b may embed SLPP in the LPP using LPP messages embedded in SUPL User Plane Location Protocol (ULP) messages while supporting UEs in subgroups 212 and 214, respectively. Additionally or alternatively, LPP and / or SLPP messages may be used, with SLPP messages not embedded in LPP messages (although LPP or SLPP messages may still be embedded in SUPL ULP messages). Additionally, UEs in each subgroup, and UEs in different subgroups, may exchange SLPP messages with each other to support and coordinate SL positioning.

[0063]

[0088] Location server (e.g., LMF / SUPL SLP / Server1 / Server2 / Server3) support for a particular UE or UEs may not be visible to other UEs in the group. For example, location server support from PLMN1 140a for UEs in subgroup 212 may not be visible to UEs in subgroup 214, and may not be visible to out-of-coverage UEs in subgroup 216. The support provided by the location server to the UEs may include determining or verifying SL PRS configurations and calculating location results for UEs, including supported and unsupported UEs (e.g., calculating location results for UEs in the supported subgroup and, if location information for UEs in the unsupported subgroup is provided to the location server, location results for UEs in the unsupported subgroup). In some implementations, signaling between location servers in separate networks can be used to provide more complete network support. As shown, LMF-LMF or SUPL SLP-SUPL SLP signaling may be used (e.g., SLPP in FIG. 2) to enable more complete network support. ** An extension to SLPP (called

[0064]

[0089] SLPP message types may be consistent with LPP message types to allow LPP messages to include embedded SLPP messages and / or to allow SLPP procedures to be consistent with LPP procedures, which may reduce implementation and / or testing. Figure 2 shows signaling (e.g., SLPP messages or SLPP messages embedded in LPP messages) between LMF1 120a and one or more of the UEs in subgroup 212, and signaling between LMF2 120b and one or more of the UEs in subgroup 214. Figure 2 also shows LPP messages, or LPP messages including embedded SLPP messages, embedded in SUPL ULP messages exchanged between SUPL SLP1 119a and one or more of the UEs in subgroup 212, and between SUPL SLP2 119b and one or more of the UEs in subgroup 214. SLPP may include messages similar to the LPP capability request and capability provision messages, which may be referred to, for example, in SLPP as "capability and resource requests" and "capability and resource provision." Capability and resource requests / provisions in SLPP may initially be limited to NR SL PRS capabilities and resources, but may later be expanded to capabilities and resources for LTE SL PRS, RTK, Wi-Fi, BT, etc.

[0065]

[0090] In another example, the SLPP may include messages similar to the LPP Assistance Data Provide message, which may be referred to, for example, in SLPP as a "positioning signal configuration provide" (or simply as an "assistance data provide"). A positioning signal configuration provide in SLPP may include, for example, one or more of the SL PRS configurations to be transmitted by each UE and measured by other UEs, the start time and duration of transmission and the condition for the end of transmission, and the type of SL PRS measurement requested, such as Rx-Tx, AOA, RSRP, RSRD, TOA, TDOA, etc. In some implementations, the positioning signal configuration provide in SLPP may be extended to define other types of signals, such as RTK signals to be measured, Wi-Fi signals to be transmitted and measured, etc. The positioning signal configuration provide in SLPP may include additional information, for example, to assist the UE in acquiring and measuring signals (e.g., SL PRS signals) and to determine the times of transmission and measurement.

[0066]

[0091] In another example, SLPP may include messages such as "positioning signal configuration confirm" (or "assistance data confirmation provide"), which do not have an analogous LPP message. The positioning signal configuration confirm in SLPP may, for example, confirm whether the positioning signal configuration provide (or assistance data provide) is agreeable. If the positioning signal configuration provide is not (partially) agreeable, a different configuration may be provided as the positioning signal configuration provide. Since LPP does not have an analogous message, if SLPP messages are embedded in LPP messages, a new LPP message type may be added to carry the positioning signal configuration confirm SLPP message. However, such a new LPP message type may not be needed when SLPP messages are not embedded in LPP messages.

[0067]

[0092] In another example, SLPP may include messages similar to LPP Provide Location Information messages, which may be referred to as "Provide Location Information" messages in SLPP. Provide Location Information messages in SLPP may include and provide SL PRS measurements obtained by the UE for SL PRS transmitted by one or more other UEs and / or may include and provide location results obtained for the UE and / or other UEs. Provide Location Information in SLPP may be extended to include and provide other measurements, such as measurements of RTK, Wi-Fi, BT, etc.

[0068]

[0093] As shown in FIG. 2 , UEs in each subgroup and UEs in different subgroups may signal each other using SLPP (e.g., when a UE sends an SLPP message to one or more other UEs). In addition, a location server (e.g., an LMF, a SUPL SLP, or Servers 1-3) may support UEs using SLPP (as described above). As previously mentioned, according to some embodiments, SLPP may be embedded in LPP, or embedded in both LPP and SUPL, or may be transmitted without being embedded in LPP. Thus, a first UE may receive a first SLPP message from a second UE and may send the first SLPP message to a location server supporting the first UE. The first UE may receive a second SLPP message from the location server in response to the first SLPP message and may send the second SLPP message to the second UE.

[0069]

[0094] Figure 3 is a signal flow 300 illustrating signaling between UE 105A, UEs 105B, 105C, and 105D, and a location server 302 for network-supported sidelink positioning as described herein, by way of example. UEs 105A, 105B, 105C, and 105D may belong to the same group, e.g., UE 105 shown in Figure 1, or any of the UEs shown in network-supported subgroups 212 and 214 of Figure 2. Location server 302 may be LMF 120, SUPL SLP 119, server 121, or server 123 shown in Figure 1, or LMF1 120a or SUPL SLP1 119a shown in Figure 2.

[0070]

[0095] As shown in FIG. 3, at 310, the UE 105A receives a first sidelink positioning message from the UE 105B. The first sidelink positioning message may be, for example, an SLPP message as described above, or any of the message types described above. The first sidelink positioning message may be sent based on SL multicasting (also called SL groupcasting) or SL unicasting, for example, if the group includes three or more UEs, as shown in FIG. 3. In SL multicasting (also called SL groupcasting), a sidelink positioning message (e.g., an SLPP message) may be transmitted that includes a group destination address (e.g., that may be partially or completely included in a Layer 1 protocol header and / or a Layer 2 protocol header in the sidelink positioning message). A receiving UE (e.g., the UE 105A) belonging to the group with this group destination address then recognizes the group destination address in the sidelink positioning message and receives, decodes, and processes the sidelink positioning message. In SL unicast, the sidelink positioning message may be sent including a UE destination address (e.g., a Layer 2 address assigned to UE 105A) and will only be received, decoded, and processed by the UE (e.g., UE 105A) whose destination address is included.

[0071]

[0096] At 320, the UE 105A sends a first LPP / SLPP message (e.g., a first SLPP message or a first SLPP message embedded in an LPP message, as described above) to the location server 302, where the first SLPP message is based on or comprises the first sidelink positioning message.

[0072]

[0097] At 330, UE 105A receives a second LPP / SLPP message from location server 302 in response to the first LPP / SLPP message from 320. The second LPP / SLPP message may be a second SLPP message or a second SLPP message embedded in an LPP message, as described above, and may be any of the message types described above. The second LPP / SLPP message (e.g., the second SLPP message) may include a location result for at least one UE in the group (e.g., UE 105A or UE 105B). For example, the location result for at least one UE in the group may include at least one of a range between the at least one UE and another UE, a direction from the at least one UE to another UE, a location of the at least one UE relative to a location of another UE, a velocity of the at least one UE, a relative velocity of the at least one UE relative to the velocity of another UE, or some combination thereof.

[0073]

[0098] At 340, the UE 105A may send a second sidelink positioning message to one or more of the UEs 105B, 105C, and 105D in the group. The second sidelink positioning message may be an SLPP message and may be based on or include the second SLPP message received at 330. The second sidelink positioning message may be sent based on SL multicast, for example, as shown in FIG. 3, if the group includes three or more UEs.

[0074]

[0099] The sidelink positioning messages in the signal flow 300 may be any of the message types described above. For example, the first sidelink positioning message at 310 and the first LPP / SLPP message at 320 may include sidelink positioning capabilities, sidelink positioning resources, or both for at least one UE in the group, e.g., UE 105B. The first LPP / SLPP message at 320 may include an LPP capability provision message and / or an SLPP capability provision message (e.g., if the SLPP capability provision message can be embedded in the LPP capability provision message). The second LPP / SLPP message at 330 and the second sidelink positioning message at 340 may include sidelink positioning capabilities, sidelink positioning resources, or both for UE 105A. The second LPP / SLPP message at 330 may include an LPP capability provision message and / or an SLPP capability provision message.

[0075]

[0100] In another example, the first sidelink positioning message at 310 and the first LPP / SLPP message at 320 may include an SL positioning reference signal (PRS) configuration for at least one UE in the group, e.g., UE 105A and / or UE 105B. The first LPP / SLPP message at 320 may include an LPP Request Assistance Data message, an LPP Provide Assistance Data message, an SLPP Request Assistance Data message, and / or an SLPP Provide Assistance Data message (e.g., where SLPP messages may be embedded in the same type of LPP message). The second LPP / SLPP message at 330 and the second sidelink positioning message at 340 may include an SL positioning reference signal (PRS) configuration for at least one UE in the group, e.g., UE 105A or UE 105B. The second LPP / SLPP message at 330 may include an LPP Provide Assistance Data message and / or an SLPP Provide Assistance Data message (eg, where an SLPP Provide Assistance Data message may be embedded in an LPP Provide Assistance Data message).

[0076]

[0101] In another example, the first sidelink positioning message at 310 and the first LPP / SLPP message at 320 may include sidelink positioning measurements obtained by at least one UE in the group, e.g., UE 105B. The first LPP / SLPP message at 320 may include an LPP Provide Location Information message and / or an SLPP Provide Location Information message (e.g., where the SLPP Provide Location Information message may be embedded in the LPP Provide Location Information message). The second LPP / SLPP message at 330 may include location results for at least one UE in the group, and the second LPP / SLPP message may include an LPP Provide Location Information message and / or an SLPP Provide Location Information message (e.g., where the SLPP Provide Location Information message may be embedded in the LPP Provide Location Information message).

[0077]

[0102] The location server 302 may be, for example, an LMF or a SUPL SLP. If the location server 302 is a SUPL SLP, the first LPP / SLPP message is sent by the UE 105A to the location server 302 as part of a first SUPL message at 320, and the second LPP / SLPP message is received by the UE 105A from the location server 302 as part of a second SUPL message at 330. The first SUPL message and the second SUPL message may each include a SUPL POS message.

[0078]

[0103] 4A is a block diagram 400A illustrating, by way of example, one implementation of the structure of an SLPP message 410. As shown, the SLPP message 410 includes a header 412 that may include a session ID, a transaction ID, a sequence number (seq no), an acknowledgment (or acknowledgement) sequence number, etc. The SLPP message 410 allows for one or more positioning methods or positioning method types. For example, the SLPP message 410 includes entries for positioning method / type 1 414, positioning method / type 2 416, and positioning method / type M 418 (e.g., M may be equal to 3 or greater). A positioning method may use, for example, one or more specific signal types (e.g., SL NR PRS, SL LTE PRS, Wi-Fi, or GPS L1-L5) and support one method of determining location for that specific signal type (e.g., one of RTT, AOA, RSRP, or TDOA). On the other hand, a positioning method type uses one or more specific signal types and supports multiple positioning methods for the one or more signal types. For example, a positioning method type may use SL PRS signals (e.g., either SL NR PRS signals or both SL NR PRS signals and SL LTE PRS signals) and support multiple positioning methods using these SL PRS signals (e.g., support all of RTT, AOA, RSRP, and TDOA). Another positioning method type may use GNSS signals and support multiple positioning methods using GNSS signals (e.g., support GNSS code phase-based positioning and GNSS carrier phase-based positioning such as RTK).

[0079]

[0104] The SLPP message 410 may be configured to support a positioning method or positioning method type (also referred to as a positioning type), or both a positioning method and a positioning method type. As shown, each positioning method / type 414, 416, and 418 in the SLPP message 410 may include parameters for each UE in the group, shown as identified by a member ID, e.g., UE1, UE2, ...UEn. It is possible that not all UEs in a group support the same positioning method / type, which may mean that parameters for UEs that do not support positioning method / type 414, 416, or 418 may not be present for that positioning method / type in the SLPP message 410. Support for multiple positioning methods or positioning method types in the SLPP message 410 may be advantageous when UEs do not all support the same positioning method or the same positioning method type, for example, some UEs may support positioning using RTK and SL PRS, while some other UEs support only RTK. However, in some implementations, the SLPP message 410 may provide support for only one positioning method (e.g., NR SL PRS RTT) or one positioning method type (e.g., NR SL PRS). FIG. 4B is a block diagram 400B illustrating another implementation of the structure of an SLPP message 420. Similar to the block diagram 400A of FIG. 4A, the SLPP message 420 includes a header 422 that may contain information similar to the header 412 in FIG. 4A. However, here, the data may be structured so that each UE in a group of n UEs has separate message sections 424, 426, and 428 in the SLPP message 420, each containing that UE's parameters for each positioning method / type 1 through M supported by that UE.

[0080]

[0105] The SLPP messages 410 and 420 shown in Figures 4A and 4B may include other information at other protocol levels used to transmit (and transport) the SLPP messages, such as the level 2 address of the UE sending or receiving the SLPP message, and / or the level 2 group address for a group of UEs to which the SLPP message is sent by multicast (also called groupcast).

[0081]

[0106] Note that the SLPP messages shown in Figures 4A and 4B may be used for positioning a UE. SLPP messages that are not used directly for positioning a UE, but instead are used to manage an SLPP session (e.g., to initiate, modify, or terminate an SLPP session, as described below with respect to Figures 11-18), may include other parameters, such as IDs and addresses for UEs participating in the SLPP session, and may not include parameters for the SL positioning method and positioning method type as shown in Figures 4A and 4B. However, such "non-positioning" SLPP messages may still include the header 412 shown in Figures 4A and 4B.

[0082]

[0107] FIG. 5 is a signal flow 500 illustrating, by way of example, signaling between a UE 105A and a UE 105B for pair-wise sidelink positioning involving only two UEs. The UEs 105A and 105B may be, for example, the UEs shown in FIG. 1 or any two of the UEs shown in group 210 shown in FIG. 2. The sidelink positioning shown in FIG. 5 may be network-independent, and thus the UEs shown in FIG. 5 may be out-of-coverage UEs in subgroup 216. The signaling performed in signal flow 500 may be similar or identical to the SLPP signaling described above with reference to FIG. 2. Signal flow 500 illustrates a simple type of SLPP session between UE 105A and UE 105B, with or without explicit session establishment and termination.

[0083]

[0108] In stage 0 of FIG. 5, UE discovery and establishment of a sidelink communication session or a sidelink positioning session may be performed. The discovery process may be request-response or announcement-based. The discovery phase may be performed by one or both of the UEs 105A and 105B, for example, to detect other UEs available for sidelink positioning. For example, discovery messages may be exchanged between the UE 105A and / or the UE 105B to determine nearby UEs available to participate in sidelink positioning. For example, the UE 105A may broadcast a discovery-based message using sidelink signaling, and the UE 105B may receive and respond to the discovery-based message by sending a similar discovery-based response message back to the UE 105A using sidelink signaling. Additional messages may be exchanged between the UE 105A and the UE 105B to explicitly establish a sidelink communication or positioning session between the UEs 105A and 105B. For example, UE 105A may send a request (e.g., SLPP request) to UE 105B to initiate an SLPP positioning session, and UE 105B may return a response (e.g., SLPP response) to UE 105A agreeing to initiate the SLPP positioning session.

[0084]

[0109] In stage 1, the UEs 105A and 105B may exchange SLPP capabilities, resources, and service requirements, which may include quality of service (QoS), using, for example, SLPP capability and resource request messages and SLPP capability and resource provision messages, as described above. Exchanging SLPP capabilities, resources, and service requirements may include both the UE 105A and the UE 105B sending their capabilities, resources, and service requirements to the other UE, or only one of the UE 105A or the UE 105B sending its capabilities, resources, and service requirements to the other UE. The exchanged capabilities may define what each of the UEs 105A and 105B is implemented to support. The exchanged resources may define which capabilities each of the UEs 105A and 105B is authorized to support and / or which capabilities each of the UEs 105A and 105B is not authorized to support. The sidelink positioning capabilities that a UE is or is not allowed to support may include permissions or restrictions on one or more of the following: sidelink PRS transmission time, sidelink PRS measurement time, sidelink PRS transmission duration, sidelink PRS measurement duration, bandwidth of sidelink PRS that may be transmitted, bandwidth of sidelink PRS that may be measured, RF frequency of sidelink PRS that may be transmitted, RF frequency of sidelink PRS that may be measured, signal coding of sidelink PRS that may be transmitted, signal coding of sidelink PRS that may be measured, periodicity of sidelink PRS transmission, periodicity of measured sidelink PRS, transmit power for sidelink PRS transmission, transmit power for measured sidelink PRS, or any combination thereof.

[0085]

[0110] Sidelink positioning capabilities may be fixed and static (e.g., dependent on the UE implementation, never changed or infrequently changed via software upgrades to the UE). Sidelink positioning resources may depend on the spectrum available for SL PRS (e.g., whether PLMN-licensed spectrum for V2X, unlicensed spectrum, or Intelligent Transport System (ITS) spectrum is available and permitted for use) and / or on existing positioning sessions and / or procedures that the UE may already support or be part of. Existing positioning sessions and / or procedures may mean that the UE cannot transmit and / or measure SL PRS at certain times for a new SL positioning session because at these times the UE would need to be transmitting and / or measuring SL PRS for the existing positioning session and / or procedure. Similarly, certain SL PRS characteristics, such as frequencies or coding, already used for an existing positioning session may not be available for use for a new SL (or SLPP) positioning session. For example, the use of certain SL PRS characteristics for a new positioning session that are already in use for an existing positioning session may prevent the SL PRS transmissions for the new or existing positioning session from being uniquely identified by the UEs involved in the new or existing positioning session, which may then cause errors in location measurements and results. Controlling the use of SL PRS characteristics for the new positioning session by exchanging allowed and / or disallowed sidelink positioning resources may prevent such errors from occurring.

[0086]

[0111] The service requirements exchanged in stage 1 may include an indication of at least one of: immediate (e.g., single) location at the current time, deferred location (e.g., at a later time), periodic location, triggered location, one or more types of location results (e.g., relative location, global location, range, direction), QoS of the location results (e.g., location result accuracy, location result response time or latency, location periodicity, location reliability), or some combination thereof. The exchanged service requirements may define the type (e.g., single or periodic), accuracy, latency, periodicity, and reliability of location that each UE requests or expects in the sidelink positioning session.

[0087]

[0112] In stage 2, the UE 105A may send a proposed sidelink positioning signal configuration, e.g., PRS1 and PRS2 configurations, to the UE 105B, e.g., using an SLPP Provide Positioning Signal Configuration message or an SLPP Provide Assistance Data message, as described above. The PRS1 configuration (in this example) may define the SL PRS to be subsequently transmitted by the UE 105A, and the PRS2 configuration (in this example) may define the SL PRS to be subsequently transmitted by the UE 105B. The PRS1 and PRS2 configurations may be defined and proposed by the UE 105A based on the capabilities, resources, and service requirements exchanged in stage 1, which may include, e.g., the QoS of the UEs 105A and 105B. The PRS1 and PRS2 configurations may be the same as or similar to the PRS configurations defined in 3GPP TS 37.355 for LPP, except that they may refer to SL PRS transmissions on the sidelink communication channel between the UEs 105A and 105B. For example, the PRS1 and PRS2 configurations may each include specifications for the SL PRS transmission start time, SL PRS transmission duration, SL PRS bandwidth, SL PRS RF frequency (or frequencies), SL PRS signal coding, SL PRS transmission periodicity, SL PRS transmit power, SL PRS muting, and / or SL PRS frequency hopping. Rules and guidelines may be standardized to ensure that the proposed PRS configurations PRS1 and PRS2 are compatible with the capabilities, resource, and service requirements of UEs 105A and 105B, which may include the QoS of both UEs.

[0088]

[0113] In stage 3, UE 105B may send a message to UE 105A to confirm the proposed positioning signal configuration, e.g., the PRS1, PRS2 configuration, using, for example, an SLPP positioning signal configuration confirmation or an SLPP assistance data provision confirmation, as described above. In some implementations, UE 105B may instead reject the proposed positioning signal configuration in stage 3, and UE 105A may then propose a different positioning signal configuration until UE 105A confirms the positioning signal configuration. In some implementations, UE 105B may send a modified proposed positioning signal configuration to UE 105A, and UE 105A may confirm the modified positioning signal configuration or send another modified proposed positioning signal configuration to UE 105B. In some implementations, when the PRS1, PRS2 configuration sent in stage 2 is acceptable to UE 105B, stage 3 may be omitted, which may reduce signaling.

[0089]

[0114] In stage 4, UE 105A transmits SL positioning signals corresponding to the PRS1 configuration, and UE 105B measures these positioning signals (e.g., based on UE 105B's prior knowledge of the PRS1 configuration). UE 105B may measure, for example, one or more of the reception time-transmission time difference (Rx-Tx), round-trip signal propagation time (RTT), reference signal received power (RSRP), reference signal received quality (RSRQ), angle of arrival (AOA), and time of arrival (TOA) of the PRS1 transmitted by UE 105A.

[0090]

[0115] In stage 5, UE 105B transmits SL positioning signals corresponding to the PRS2 configuration, and UE 105A measures these positioning signals (e.g., based on UE 105A's prior knowledge of the PRS2 configuration). UE 105A may, for example, measure one or more of the RTT, Rx-Tx, RSRP, RSRQ, AOA, AOD, and TOA of the PRS2 transmitted by UE 105B.

[0091]

[0116] In step 6, UE 105A and UE 105B exchange measurements obtained in steps 4 and 5. The exchange of measurements may indicate a modified SL PRS configuration to be used in step 4 or step 5 for transmission of the SL PRS, for example, if there were any differences with respect to the PRS1 and / or PRS2 configurations (e.g., with respect to the exact time or duration of the SL PRS transmission), and may further provide the measurements generated in step 4 or step 5. As an example, if the SL positioning signal (SL PRS) transmitted by UE 105A in step 4, which corresponds to the PRS1 configuration transmitted by UE 105A in step 2, does not exactly match the PRS1 configuration (e.g., because UE 105A slightly delayed SL PRS transmission because some other UE was transmitting at the transmission time indicated in the PRS1 configuration), UE 105A may include the correct transmission time actually used by UE 105A in step 4 in the modified SL PRS configuration transmitted by UE 105A in step 6. UE 105B can later use UE 105A's correct transmit times received with the modified SL PRS configuration in step 6 when calculating any location results (e.g., step 7). Exchanging measurements in step 6 may involve both UE 105A and UE 105B sending their measurements and / or modified SL PRS configuration to the other UE, or only one of UE 105A or UE 105B sending its measurements and / or modified SL PRS configuration to the other UE.

[0092]

[0117] In step 7, UE 105A and UE 105B may each calculate a location result, e.g., a range and / or direction, a relative location, an absolute location, a velocity, a relative velocity, or any combination thereof, between UE 105A and UE 105B based on the measurements generated in steps 4 and 5 and received (or transmitted) in step 6, and / or the modified SL PRS configuration received (or transmitted) in step 6. For example, the UE may determine the range between UE 105A and UE 105B based on Rx-Tx measurements of the PRS signals or based on equivalent TODi and TOAi measurements for the PRSi signals (where i=1 for the PRS transmitted by UE 105A in step 4 and i=2 for the PRS transmitted by UE 105B in step 5, and c represents the speed of transmission of electromagnetic waves, e.g., the speed of light).

[0093]

number

[0094]

[0118] The location results determined in step 7 may then be exchanged in step 8. Exchanging location results in step 8 may involve both UE 105A and UE 105B sending their location results to the other UE, or only one of UE 105A or UE 105B sending its location results to the other UE. In the latter case, only the UE that sends its location result to the other UE may calculate the location result in step 7.

[0095]

[0119] As shown in step 9, steps 4-8 may be repeated as needed by UE 105A and UE 105B. For example, steps 4-8 may be repeated in step 9 to allow for periodic or triggered location results for UE 105A and UE 105B.

[0096]

[0120] 6A is a signal flow 600 illustrating signaling between UE 105A and UE 105B for sidelink positioning capability exchange, including an exchange of capability, resource, and service requirements that may include QoS, which may correspond to stage 1 of FIG. 5. As shown in signal flow 600, in stage 1, UE 105A may send a (e.g., SLPP) capability request message, an (e.g., SLPP) capability provision message, or an (e.g., SLPP) capability, resource, and service requirement provision message, which may include QoS, to UE 105B. In stage 2, in response to the capability request message, capability provision message, or capability, resource, and service requirement provision message, UE 105B may send a (e.g., SLPP) capability provision message, or an (e.g., SLPP) capability, resource, and service requirement provision message, which may include QoS, to UE 105A.

[0097]

[0121] 6B is a signal flow 620 illustrating signaling between UE 105A and UE 105B for a positioning signal configuration and confirmation exchange, which may correspond to steps 2 and 3 of FIG. 5. As shown, in step 1 of signal flow 620, UE 105A sends a proposed positioning signal configuration, e.g., PRS1, PRS2 configuration, to UE 105B, which corresponds to step 2 of FIG. 5 and may be included in an SLPP Provide Assistance Data message or an SLPP Provide Positioning Signal Configuration message. In step 2a, UE 105B may send to UE 105A a configuration confirm message, which corresponds to step 3 of FIG. 5 and may be an SLPP Provide Positioning Signal Configuration Confirm message or an SLPP Provide Assistance Data Confirm message. Alternatively, in step 2b, UE 105B may send to UE 105A a configuration reject message, which may be an SLPP Provide Positioning Signal Configuration Reject message or an SLPP Provide Assistance Data Reject message. In response to the configuration reject message from step 2b, UE 105A may prepare another positioning signal configuration, and steps 1 and 2a or 2b are repeated. In another implementation, in step 2c, UE 105B may provide UE 105A with the proposed modified PRS1 configuration, which may be included, for example, in a Provide SLPP Assistance Data message or a Provide SLPP Positioning Signal Configuration message. * , PRS2 *In response to step 2c, UE 105A may send a configuration confirmation message, which may be an SLPP positioning signal configuration confirmation message or an SLPP assistance data provision confirmation message, to UE 105B in step 3. Alternatively, UE 105A may further modify the positioning signal configuration by repeating steps 1 and 2a or 2b.

[0098]

[0122] Figure 6C is a signal flow 660 illustrating signaling between UE 105A and UE 105B for a measurement exchange, which may correspond to stage 6 of Figure 5. As shown in signal flow 660, in stage 1, UE 105A may send a measurement report to UE 105B, which may include information about the PRS transmitted by UE 105A in stage 4 of Figure 5, such as one or more precise times of transmission, and may further include measurements made by UE 105A of the PRS transmitted by UE 105B in stage 5 of Figure 5. The measurement report for stage 1 may be an SLPP Provide Location Information message.

[0099]

[0123] Similarly, in stage 2, UE 105B may send a measurement report to UE 105A, which may include information about the PRS transmitted by UE 105B in stage 5 of Figure 5, such as one or more precise times of transmission, and may further include measurements made by UE 105B of the PRS transmitted by UE 105A in stage 4 of Figure 5. The measurement report for stage 2 may be an SLPP Provide Location Information message.

[0100]

[0124] Therefore, the sidelink positioning message sent by the UE 105A may include the sidelink positioning capabilities and sidelink positioning resources of the UE 105A, as described for stage 1 of Fig. 5 and as described for stage 1 shown in Fig. 6A. The sidelink positioning message may further include the sidelink positioning service requirements of the UE 105A, as described for stage 1 of Fig. 5 and Fig. 6A.

[0101]

[0125] Additionally, the UE 105A may receive a second sidelink positioning message from the UE 105B. For example, the second sidelink positioning message received from the UE 105B may include the sidelink positioning capabilities and sidelink positioning resources of the UE 105B, as described for step 1 of FIG. 5 and step 2 of FIG. 6A. The second sidelink positioning message received from the UE 105B may further include the sidelink positioning service requirements of the UE 105B, as described for step 1 of FIG. 5 and step 2 of FIG. 6A.

[0102]

[0126] As shown for steps 2-8 of Figure 5, the UE 105A may exchange additional sidelink positioning messages with the UE 105B, which may be based on the UE 105B's sidelink positioning capabilities and sidelink positioning resources. Each of the additional sidelink positioning messages may be further based on the UE 105B's sidelink positioning service requirements. For example, as described for steps 2-8 of Figure 5 and in signal flows 620 and 660 of Figures 6B and 6C, the additional sidelink positioning messages exchanged with the UE 105B may include a proposed positioning signal configuration, a confirmation (or rejection or modification) of the proposed positioning signal configuration, a request for measurements and / or measurements on the sidelink positioning PRS, and a location result determined from the sidelink positioning PRS measurements.

[0103]

[0127] As indicated by step 7 of FIG. 5, the UE 105A may determine the location of the UE 105B based on the additional sidelink positioning message.

[0104]

[0128] The pairwise sidelink positioning illustrated in Figures 5, 6A, 6B, and 6C can be extended and expanded for group operation, e.g., with a group of UEs, as illustrated by UE group 210 in Figure 2. The group of UEs may, for example, be small enough to allow direct discovery and direct sidelink signaling between UEs in the group of UEs. The various sidelink positioning messages transmitted by UEs in the group can be transmitted using groupcast or multicast, such that each sidelink positioning message is broadcast once to all receiving UEs using sidelink signaling.

[0105]

[0129] FIG. 7 shows a signal flow 700 illustrating signaling for group operation of sidelink positioning for multiple UEs, shown as UEs 105A, 105B, 105C, ..., 105Z, sometimes collectively referred to as UEs 105, by way of example. The group of UEs 105 may include a small number of UEs (e.g., up to 20) for which direct discovery and direct SL signaling are possible. The UEs 105 may be, for example, any of the UEs shown in FIG. 1 or any of the UEs shown in group 210 shown in FIG. 2. The sidelink positioning shown in FIG. 7 is network-independent; therefore, the UEs shown in FIG. 7 may be out-of-coverage UEs in subgroup 216 of FIG. 2. The signaling performed in signal flow 700 may be similar to or the same as the SLPP signaling described above with reference to FIG. 2 and shown in signal flow 500 of FIG. 5, except that the SLPP signaling may involve a larger number of UEs. If desired, signaling can be performed directly as shown, or via relays and / or through a network. Note that the number of UEs in signal flow 700 is typically greater than two, but may be two in limiting cases (where two of the UEs shown in FIG. 7 are not present).

[0106]

[0130] Signal flow 700 illustrates a simple type of SLPP session between UEs 105, with or without explicit session establishment and termination. When signal flow 700 is performed with explicit session establishment and termination, steps 1-11 of Figure 7 can be performed as part of signal flow 1100, described below with respect to Figure 11, in which steps 1-11 of Figure 7 replace steps 9-13 of Figure 11.

[0107]

[0131] In stage 0 of FIG. 7, discovery of UEs 105s, group formation, and establishment of a multicast sidelink communication session are performed. The discovery process can be request-response or announcement-based. The discovery phase can be performed by one or more UEs 105 to detect other UEs 105 that are available for sidelink positioning and suitable to join a group. For example, discovery messages can be exchanged between UEs 105 to determine nearby UEs 105 that are available to participate in sidelink positioning. For example, UE 105A can broadcast a discovery-based message using sidelink signaling, and UEs 105B, 105C, and 105Z can each receive and respond to the discovery-based message by each transmitting a similar discovery-based response message back to UE 105A using sidelink signaling. The UEs 105 may also exchange (or pre-configure) one or more group criteria parameters for group formation, such as an approximate maximum distance between pairs of UEs (which helps ensure that the UEs 105 can communicate directly with each other), a minimum period of time that any UE 105 may be communicating with other UEs 105 (which helps ensure that the UEs 105 can communicate directly with each other for some minimum period of time), and / or a common direction and / or common velocity range of the UEs 105 (which helps ensure that the UEs 105 stay close to each other). Based on the group criteria parameters, the UEs 105 may determine whether to form a group, which UEs 105 should or should not belong to the group, or whether and when additional UEs 105 should be added to the group later and / or whether and when existing UEs 105 should be removed from the group. For example, the UEs 105 may determine a group status indication for each UE 105 indicating inclusion or exclusion from the group. In FIG. 7, for example, it is assumed that all UEs 105A, 105B, 105C, . . . 105Z meet one or more group criteria and are included in a group.Additional messages may be exchanged between UEs 105 to explicitly establish sidelink communications or positioning sessions between UEs 105. For example, UE 105A may send a request to initiate an SLPP positioning session (e.g., an SLPP request) to UEs 105B, 105C, and 105Z, and UEs 105B, 105C, and 105Z may return a response (e.g., an SLPP response) to UE 105A agreeing to initiate the SLPP positioning session.

[0108]

[0132] In stage 1, the UEs 105 may exchange SLPP capabilities, resources, and service requirements, which may include QoS, using, for example, SLPP capability and resource request messages and SLPP capability and resource provision messages, as described above. The exchange of capabilities, resources, and service requirements, which may include QoS, may be similar to the signal flow 600 shown in FIG. 6A, but involving additional UEs. For example, the UEs 105 may first exchange capabilities by each sending a single groupcast SLPP message from each UE 105 to all other UEs 105. The exchanged capabilities may define what each UE 105 is implemented to support. The exchanged resources may define which capabilities each UE 105 is authorized to support and / or is not authorized to support. The sidelink positioning capabilities that the UE 105 is or is not authorized to support may include permissions or restrictions on one or more of the following: sidelink PRS transmission time, sidelink PRS measurement time, sidelink PRS transmission duration, sidelink PRS measurement duration, bandwidth of the sidelink PRS that may be transmitted, bandwidth of the sidelink PRS that may be measured, RF frequency of the sidelink PRS that may be transmitted, RF frequency of the sidelink PRS that may be measured, signal coding of the sidelink PRS that may be transmitted, signal coding of the sidelink PRS that may be measured, periodicity of sidelink PRS transmission, periodicity of measured sidelink PRS, transmit power for sidelink PRS transmission, transmit power for measured sidelink PRS, or any combination thereof. Sidelink positioning capabilities may be fixed and static, as described for stage 1 of FIG. 5. Sidelink positioning resources may depend on the spectrum available for SL PRS and / or on existing positioning sessions and / or procedures that the UE 105 already supports or may be part of, as described for stage 1 of FIG. 5. The service requirements of each of the UEs 105 may be as described for stage 1 of FIG.

[0109]

[0133] In stage 2, UE 105A may transmit a proposed positioning signal configuration, e.g., a PRS1, PRS2, PRS3, ..., PRSn configuration, to other UEs 105, e.g., using an SLPP Provide Positioning Signal Configuration message or an SLPP Provide Assistance Data message, as described above. The PRS1 configuration (in this example) may define the SL PRS to be transmitted later by UE 105A, the PRS2 configuration (in this example) may define the SL PRS to be transmitted later by UE 105B, the PRS3 configuration (in this example) may define the SL PRS to be transmitted later by UE 105C, and the PRSn configuration (in this example) may define the SL PRS to be transmitted later by UE 105Z, where the PRS1, PRS2, PRS3, and PRSn configurations may be defined and proposed by UE 105A based on the capabilities, resources, and service requirements exchanged in stage 1, which may include, e.g., the QoS of each of the UEs 105. The PRS1, PRS2, PRS3, and PRSn configurations may be, for example, as described for PRS1 and PRS2, respectively, for stage 2 of FIG.

[0110]

[0134] In stage 3, each of UEs 105B, 105C, ... 105Z may send a message to UE 105A to confirm a proposed positioning signal configuration, e.g., a PRS1, PRS2, PRS3, ... PRSn configuration, using, for example, an SLPP positioning signal configuration confirmation or an SLPP assistance data provision confirmation, as described above. In some implementations, UE 105 (e.g., UE 105B) may instead reject the proposed positioning signal configuration in stage 3 and further indicate which PRS configuration is being rejected. UE 105A may then propose a different positioning signal configuration (or simply a different PRS configuration for the rejected PRS configuration) until each of the other UEs 105 confirms the positioning signal configuration. In some implementations, a UE 105 (e.g., UE 105B) may send a modified proposed positioning signal configuration to UE 105A and to other UEs 105 in the group, and UE 105A and the other UEs 105 may confirm the modified positioning signal configuration or send another modified proposed positioning signal configuration to the other UEs 105. In some implementations, the PRS1, PRS2, PRS3, ... PRSn configuration sent in stage 2 may be acceptable to each of UEs 105B, 105C, ... 105Z and may be omitted in stage 3, which may reduce signaling.

[0111]

[0135] In stage 4, UE 105A transmits SL positioning signals corresponding to the PRS1 configuration, and UE 105B, UE 105C, ... UE 105Z each measure these positioning signals (e.g., based on UE 105B, UE 105C, ... UE 105Z each already knowing the PRS1 configuration). UE 105B, 105C, ... UE 105Z may each measure, for example, one or more of the reference signal time difference (RSTD), RTT, Rx-Tx, RSRP, RSRQ, AOA, AOD, and TOA of the PRS1 transmitted by UE 105A.

[0112]

[0136] In step 5, UE 105B transmits positioning signal PRS2, and the remaining UEs 105 each measure positioning signal PRS2 in the same way as they measure PRS1 in step 4.

[0113]

[0137] In step 6, the UE 105C transmits the positioning signal PRS3, and the remaining UEs 105 measure the positioning signal PRS3 in the same way as they measure PRS1 in step 4.

[0114]

[0138] In step 7, the UE 105Z transmits the positioning signal PRSn, and the remaining UEs 105 measure the positioning signal PRSn in the same way as they measured PRS1 in step 4.

[0115]

[0139] In step 8, the UEs 105 exchange measurements. The measurement exchange may be similar to signal flow 660 shown in Figure 6C, but with additional UEs, and the measurements are exchanged, for example, via a single groupcast SLPP message sent by each UE 105 to all other UEs 105 in the group. The measurement exchange may, for example, indicate a modified SL PRS configuration to be used by the UE 105 for SL PRS transmission (e.g., as described for step 6 of Figure 5), and may further provide measurements obtained by the UE 105, for example, in one of steps 4, 5, 6, or 7.

[0116]

[0140] In step 9, each UE 105 may determine a location result, e.g., range and / or direction between the UE 105 and each of one or more other UEs 105 in the group, relative locations, absolute locations, velocities, relative velocities of one or more of the UEs 105, or any combination thereof, based on the measurements generated in steps 4-7 and received (or transmitted) in step 8, and / or the modified SL PRS configuration received (or transmitted) in step 8. In some embodiments, only one UE 105 (e.g., UE 105A) or a subset of the UEs 105 may determine the location result.

[0117]

[0141] The location results determined in step 9 may then be exchanged in step 10. Exchanging location results in step 10 may involve each of UEs 105A, 105B, 105C...195Z transmitting its location result to all other UEs 105 in the group, or only one UE 105 (e.g., UE 105A) or a subset of the UEs 105 transmitting its location result to the other UEs 105. In the latter case, only the UEs 105 (or subset of UEs 105) that transmit their location result to the other UEs 105 may calculate their location result in step 9.

[0118]

[0142] As shown in step 11, steps 4-10 may be repeated as necessary by UE 105. For example, steps 4-10 may be repeated in step 11 to allow periodic or triggered location results for UE 105 to be obtained.

[0119]

[0143] Thus, as shown in FIG. 7, when a UE 105, such as UE 105A, belongs to a group of UEs including two or more UEs, the UE 105A can send a sidelink positioning message to all other UEs in the group of UEs, e.g., UEs 105B, 105C, ..., 105Z, e.g., based on sidelink multicasting. The sidelink positioning message is then broadcast or multicast once to all receiving UEs using SL signaling. For example, as described for step 1 of FIG. 7 and step 1 shown in FIG. 6A, the sidelink positioning message sent by the UE 105A may include the sidelink positioning capabilities and sidelink positioning resources of the UE 105A. The sidelink positioning message may further include the sidelink positioning service requirements of the UE 105A, as described for step 1 of FIG. 7 and FIG. 6A.

[0120]

[0144] Furthermore, as further described in step 1 of Fig. 7, the UE 105A may receive, e.g., based on sidelink multicast, a second sidelink positioning message from each of the other UEs in the group of UEs, e.g., UEs 105B, 105C, ..., 105Z. For example, as described in step 1 of Fig. 7 and in step 2 shown in Fig. 6A, the second sidelink positioning message received from each of the other UEs may include the sidelink positioning capabilities and sidelink positioning resources of each UE. The second sidelink positioning message received from each UE may further include the sidelink positioning service requirements of each UE, as described in step 1 of Fig. 7 and Fig. 6A.

[0121]

[0145] As illustrated by steps 2-8 of step 7, the UE 105A may exchange additional sidelink positioning messages with at least some of the UEs in the group of UEs, e.g., UEs 105B, 105C, ... 105Z, e.g., based on sidelink multicasting. The additional sidelink positioning messages may be based, e.g., on the sidelink positioning capabilities and sidelink positioning resources of each of the at least some UEs. Each of the additional sidelink positioning messages may be further based on the sidelink positioning service requirements of each UE 105. For example, as described in steps 2-8 of FIG. 7 and in signal flows 620 and 660 of FIGS. 6B and 6C, the additional sidelink positioning messages exchanged with at least some of the UEs may include a proposed positioning signal configuration, confirm (or reject or modify) the proposed positioning signal configuration, and / or request or provide measurements of the SL PRS.

[0122]

[0146] As indicated by stage 9, UE 105A may determine location results for at least some of the UEs based on the additional sidelink positioning messages.

[0123]

[0147] For group operation of sidelink positioning as shown in Figure 7, groups of UEs should be initially determined and optionally formed, for example based on one or more criteria. Furthermore, when UEs leave or enter a group area, modification of the groups of UEs may be necessary.

[0124]

[0148] Group determination and formation for sidelink positioning may use, for example, Proximity-based Services (ProSe) or V2X services for group discovery and establishment as shown in stage 0 of Figures 5 and 7. Various criteria may be used to include UEs in the same group. For example, one criterion for inclusion in a group may be the capability for discovery via ProSe or V2X and the capability to communicate directly (via sidelink signaling) with other UEs in the group. Other criteria may include a maximum distance restriction, e.g., that excludes from the group any UE that is generally farther from other UEs in the group than a maximum distance threshold; a time restriction, e.g., that excludes from the group any UE that is communicating (or likely to be communicating) with other UEs in the group for less than a minimum duration threshold; and a direction or speed restriction, e.g., that excludes from the group any UE that is moving in a different direction than other UEs in the group or at a speed that differs from the speed of other UEs in the group by more than a maximum speed difference threshold. The criteria, e.g., thresholds for determining whether a UE meets various requirements for joining a group, may depend on the environment and application. For example, the distance, time, and direction or speed criteria used in group formation for V2X highway, V2X local road, or V2X parking lot applications may vary. Once a group is established, periodic ProSe or periodic V2X signaling may be used to determine when a UE should leave the group and when a new UE should join the group, for example, based on whether the group criteria are met. Within a group, UEs may be assigned a member ID (e.g., 1, 2, 3, etc.) for identification within the group and in SLPP messages. The group member ID may be used to determine which UE will lead, coordinate, and / or initiate an SLPP positioning session, positioning method, or positioning method type, e.g., which UE will propose a PRS configuration to other UEs, as shown in step 2 of Figures 5 and 7.A group may be restricted to only one positioning method type (e.g., SL NR PRS), while other positioning method types (e.g., SL LTE PRS or RTK) may be used by different groups. Restricting a group to one positioning method type may avoid scenarios where not all UEs in the group support the same positioning method type and may simplify procedures and messaging. Alternatively, to maximize signaling efficiency, the same group of UEs may employ multiple positioning method types and / or multiple positioning methods, and not all UEs in the group necessarily support the exact same positioning method type or the exact same positioning method.

[0125]

[0149] FIG. 8 is a signal flow 800 illustrating, by way of example, signaling between UEs for pair-wise mode sidelink positioning. UE 105A and UE 105B may be, for example, the UEs shown in FIG. 1 and any two of the UEs shown in group 210 shown in FIG. 2. The sidelink positioning shown in FIG. 8 may be network-independent; therefore, UE 105 shown in FIG. 8 may be an out-of-coverage UE in subgroup 216. The signaling performed in signal flow 800 may be similar or the same as the SLPP signaling described above with reference to FIG. 2 and shown in signal flow 500 of FIG. 5. Signal flow 800 illustrates another simple type of SLPP session between UE 105A and UE 105B, with or without explicit session establishment and termination.

[0126]

[0150] In phase 1, UE discovery and establishment of a sidelink communication connection, association, link, or session are performed. The discovery phase may be implemented by one or both of the UEs 105A and 105B, for example, to detect other UEs available for sidelink positioning (including, for example, detecting each other). For example, discovery messages indicating whether the UEs are authorized to support pairwise-mode sidelink positioning sessions may be exchanged between the UEs 105A and / or 105B to determine nearby UEs available to participate in sidelink positioning. Additional messages may optionally be exchanged to explicitly establish a sidelink positioning session between the UEs 105A and 105B. In FIG. 8, for example, it is assumed that both the UEs 105A and 105B are authorized to support pairwise-mode sidelink positioning sessions.

[0127]

[0151] In some embodiments, signal flow 800 may optionally include stage 2 in which security may be established between UEs 105A and 105B, for example, SLPP messages sent later in stages 3, 4, and 6 are encrypted.

[0128]

[0152] In stage 3, the UE 105A may transmit to the UE 105B an SL positioning reference signal (PRS1) configuration to be transmitted by the UE 105A using SL at one or more subsequent times. This may be transmitted in an SLPP Provide Assistance Data message. In some embodiments, the SL PRS configuration may be included in the UE 105B and unicast to the UE 105B. In some embodiments, the PRS1 configuration may include when and how the UE 105A may transmit SL PRS occasions. In some embodiments, the transmission time may be indicated using GNSS time or Coordinated Universal Time (UTC), or may be relative to the UE's local time. For example, when using UE local time, the UE may include a timestamp in the transmission indicating the local UE time at which any transmission (e.g., a particular portion of the transmission, such as the initial bit or initial octet) was or should have been transmitted. Each UE may then calculate real time differences (RTDs) between its own local time and the local times of the other UEs based on the difference between its own local time and the local times of the other UEs indicated in transmissions received from these other UEs, with corrections based on estimates of propagation delays between the UEs (or ignoring the propagation delays and treating them as negligible). Each UE (e.g., UE A) may then include a local time timestamp in SLPP messages sent to other UEs, which any other UE (e.g., UE B) may convert using the RTDs that it previously calculated for the UE A and B pair.

[0129]

[0153] The PRS1 configuration may be the same as or similar to the PRS configuration defined in 3GPP TS37.355 for LPP, except that the PRS1 configuration may refer to, for example, a PRS transmission on a sidelink communication channel between two UEs.

[0130]

[0154] In stage 4, and in response to receiving the PRS1 configuration in stage 3, the UE 105B may transmit a positioning reference signal (PRS2) configuration to be transmitted by the UE 105B at one or more subsequent times. This may be transmitted in a Provide SLPP Assistance Data message. In some embodiments, the PRS2 configuration may be included and unicast to the UE 105A. In some embodiments, the PRS2 configuration may include when and how the UE 105B may transmit SL PRS occasions.

[0131]

[0155] In step 5, both UE 105A and UE 105B transmit and measure SL PRSs (e.g., PRS1 and PRS2). For example, UE 105A transmits SL positioning signal PRS1, and UE 105B measures positioning signal PRS1. UE 105B may, for example, measure the RSSI, RTT, RSRP, RSRQ, AOA, AOD, and TOA of PRS1 transmitted by UE 105A. UE 105B also transmits SL positioning signal PRS2, and UE 105A measures positioning signal PRS2. UE 105A may, for example, measure the RSSI, RTT, RSRP, RSRQ, AOA, AOD, and TOA of PRS2 transmitted by UE 105B. After determining the measurements, UE 105A and UE 105B exchange measurements in step 6 by each transmitting an SLPP Measurement Report message or an SLPP Provide Location Information message comprising the measurements obtained by each UE. The exchange of measurements may also include modified PRS1 and PRS2 configurations, which may indicate, for example, the exact transmission time, AOD, signal power, etc. of the transmitted signal (PRS1 or PRS2), as well as provide the measurements obtained in step 5.

[0132]

[0156] Following step 6, the UE may determine the range between the UEs based on the measurements and / or modified PRS1 and PRS2 configurations, and / or may determine other location results based on the measurements, such as the direction between the UEs, the relative location of one UE to the other UE, the relative velocity of one UE to the other UE, or any combination thereof. For example, the range may be determined as described for step 7 of FIG. 5.

[0133]

[0157] In some embodiments, steps 5 and 6 may be repeated as necessary (eg, as shown in steps 3 and 4).

[0134]

[0158] In some embodiments, exchange of UE capabilities and resources may not be required, for example, the Sidelink Positioning Protocol (SLPP) for a pairwise mode sidelink positioning session may define a minimum core set of capabilities and / or resources that all UEs participating in the session should be allowed to support.

[0135]

[0159] Figure 9 is a signal flow 900 illustrating, by way of example, signaling between UEs for pair-wise mode sidelink positioning. UE 105A and UE 105B may be, for example, the UEs shown in Figure 1 and any two of the UEs shown in group 210 shown in Figure 2. The sidelink positioning shown in Figure 9 may be network independent, and thus the UE shown in Figure 8 may be an out-of-coverage UE in subgroup 216. In Figure 9, explicit signaling is used to establish and later terminate an SLPP positioning session between UEs 105A and 105B.

[0136]

[0160] In phase 1, UE discovery and establishment of a sidelink communication session, association, link, or connection is performed. The discovery phase may be implemented by one or both of the UEs 105A and 105B, for example, to detect other UEs available for sidelink positioning (including, for example, detecting each other). For example, discovery messages indicating whether the UEs are authorized to support pairwise-mode sidelink positioning sessions may be exchanged between the UEs 105A and / or 105B to determine nearby UEs available to participate in sidelink positioning. In FIG. 9, for example, it is assumed that both the UEs 105A and 105B are authorized to support pairwise-mode sidelink positioning sessions.

[0137]

[0161] In some embodiments, signal flow 700 may optionally include stage 2 in which security may be established between UE 105A and 105B, for example, SLPP messages sent later in stages 3, 4, 5, 6, 8, 9, and 10 are encrypted.

[0138]

[0162] In stage 3, the UE 105A (which may be referred to as the "anchor," "anchor UE," "cooperating UE," "coordinator," or "initiating UE") may request the UE 105B to participate in the pairwise mode sidelink positioning session, for example, by transmitting (send) an SLPP session request message to the UE 105B, the SLPP session request message including a session ID. In some embodiments, the SLPP session request message may include information regarding parameters for duration, number of measurement reports, QoS, successful termination of the session, etc.

[0139]

[0163] In step 4, the UE 105B may accept or reject the request, for example, by sending an SLPP session accept (step 4a) or SLPP session reject (step 4b) message. As shown in Figure 7, for example, assume that the UE 105B accepts the join request (e.g., step 4a). Following step 4a, an SLPP positioning session may be established between the UEs 105A and 105B.

[0140]

[0164] In stage 5, the UE 105B may transmit its sidelink positioning capabilities and / or resources to the UE 105A. In some embodiments, the sidelink positioning capabilities may include service requirements, which may include capabilities, resources (e.g., time available to transmit and / or measure SL PRS), and QoS. In some embodiments, the UE 105A may first transmit a capability request message to the UE 105B.

[0141]

[0165] In step 6, the UE 105A may determine and transmit a proposed SL positioning reference signal (PRS) configuration, e.g., PRS1 and PRS2 configuration, to the UE 105B, e.g., using an SLPP Provide Assistance Data message. The PRS1 and PRS2 configurations may be defined and proposed by the UE 105A, e.g., based on the capabilities, resources (and possibly service requirements) received by the UE 105A in step 5. The PRS1 and PRS2 configurations may be the same or similar to the PRS configurations defined in 3GPP TS37.355 for LPP, except that the PRS1 and PRS2 configurations may refer to PRS transmissions on a sidelink communication channel between two UEs or groups of UEs. Rules and guidelines may be standardized to ensure that the proposed SL PRS configuration is compatible with the capabilities, resources, and service requirements, which may include QoS, of both UEs. The PRS1 configuration may be indicated to be transmitted by the UE 105A, and the PRS2 configuration may be indicated to be transmitted by the UE 105B.

[0142]

[0166] In step 7, both UE 105A and 105B transmit and measure SL PRS according to the SL PRS configuration transmitted by UE 105A in step 6 (e.g., PRS1 is transmitted by UE 105A and measured by UE 105B, and PRS2 is transmitted by UE 105B and measured by UE 105B). For example, UE 105A transmits positioning signal PRS1, and UE 105B measures positioning signal PRS1. UE 105B may measure, for example, the Rx-Tx, RSSI, RTT, RSRP, RSRQ, AOA, AOD, and TOA of PRS1 transmitted by UE 105A. UE 105B also transmits positioning signal PRS2, and UE 105A measures positioning signal PRS2. UE 105A may, for example, measure the Rx-Tx, RSSI, RTT, RSRP, RSRQ, AOA, AOD, and TOA of PRS2 transmitted by UE 105B.

[0143]

[0167] In step 8, UE 105A and UE 105B may determine and exchange SLPP measurement reports (or SLPP location information provision messages) that include the measurements obtained in step 7. The exchange of measurements may also include modified PRS1 and PRS2 configurations, indicating, for example, the actual transmission time, AOD, signal power, etc., of the transmitted PRS1 and PRS2 signals. The UEs may then determine range based on the measurements and / or other location results based on the measurements, such as direction between the UEs, relative location of one UE to the other UE, relative velocity of one UE to the other UE, or any combination thereof. For example, range may be determined as described for step 7 of FIG. 5.

[0144]

[0168] In some embodiments, steps 7 and 8 may be repeated periodically as needed.

[0145]

[0169] In steps 9 and 10, UE 105A and / or UE 105B may explicitly terminate the pairwise mode sidelink positioning session if the session needs to end at a time different from (e.g., before or after) any scheduled termination, e.g., as indicated in the session request sent in step 3. For example, UE 105A and / or UE 105B may send a termination request to the other UE indicating the end of the pairwise mode sidelink positioning session and terminate the session accordingly.

[0146]

[0170] FIG. 10 is a diagram 1000 illustrating, by way of example, an implementation of a group mode sidelink positioning system, according to one embodiment. UE1, UE2, and UE3 may be, for example, UEs 105A, 105B, and 105C shown in FIG. 1 and any three of the UEs shown in group 210 shown in FIG. 2. The sidelink positioning shown in FIG. 10 may be network independent, and therefore the UEs shown in FIG. 10 may be out-of-coverage UEs in subgroup 216. The signaling performed in diagram 1000 may be similar or the same as the SLPP signaling described above with reference to FIG. 2 and may be illustrated as signal flow 700 in FIG. 7 and signal flows 1100, 1200, 1300, 1400, 1500, 1600, 1700, and 1800 described below with reference to FIGS. 11-18.

[0147]

[0171] As shown in FIG. 10 , three anchor (or “cooperative”) UEs (e.g., UE1, UE2, and UE3) may each cover and manage a corresponding control area (e.g., control areas 1010, 1020, and 1030). Within each control area, other UEs discovered by the anchor UE associated with the control area and located within the control area may be grouped by the anchor UE into a single group or several subgroups (e.g., group 1015 for UE1, comprising subgroups 1015-1 and 1015-2; group 1025 for UE2; and group 1035 for UE3). In some embodiments, the corresponding anchor UE may coordinate group mode sidelink positioning sessions for the group UEs or for each separate subgroup of UEs. In some embodiments, different control areas may overlap. For example, group 1015 could overlap with group 1025 and / or group 1035.

[0148]

[0172] In some embodiments, an anchor (or cooperating) UE may be a UE that has anchor (or cooperating) UE capability. For example, anchor capability may include having a precisely known location and greater capabilities than other UEs (e.g., GNSS capability, multiple antennas, more processing and storage resources, etc.). In some embodiments, an anchor UE may be a roadside unit (RSU) for V2X, trucks, buses, etc. In some embodiments, two or more UEs with anchor UE capability may be grouped into the same group that performs the same group mode sidelink positioning session. In that case, any one of the UEs with anchor UE capability may serve as the anchor UE for the group (e.g., through negotiation).

[0149]

[0173] Within each group or subgroup (e.g., group 1015, subgroup 1015-1, subgroup 1015-2, group 1025, and / or group 1035), the group mode sidelink positioning session may be managed entirely by the corresponding anchor UE (e.g., UE1 for group 1015 or subgroups 1015-1 and 1015-2, UE2 for group 1025, and UE3 for group 1035), and other UEs in the group may perform positioning by associating with the corresponding anchor UE (e.g., by joining the group mode sidelink positioning session). In some embodiments, the association between the anchor UE and other UEs in the group may be configured to manage the positioning of the group mode sidelink positioning session.

[0150]

[0174] In some embodiments, each group may be organized into one or more subgroups (e.g., subgroup 1015-1 and subgroup 1015-2), for example, based on the location of the UE (e.g., a control area may be divided into different subareas, each corresponding to a subgroup of group mode sidelink positioning sessions).

[0151]

[0175] FIG. 11 shows a signal flow 1100 illustrating signaling between UEs for group mode sidelink positioning of multiple UEs, shown by way of example as UEs 105A, 105B, 105C, 105D, ... 105n, sometimes collectively referred to as UEs 105. The group of UEs may include a small number of UEs (e.g., up to 20) capable of direct discovery and direct sidelink signaling. The UEs 105 may be, for example, the UEs 105 shown in FIG. 1 and any of the UEs shown in group 210 shown in FIG. 2. The sidelink positioning shown in FIG. 11 may be network-independent; therefore, the UEs shown in FIG. 11 may be out-of-coverage UEs in subgroup 216. The signaling performed in signal flow 1100 may be similar or identical to the SLPP signaling described above with reference to FIG. 2 and shown in signal flow 700 of FIG. 7. If desired, the signaling may be performed directly as shown, or via a relay and / or via the network. As mentioned above, only some of the group of UEs may be target UEs, but the signal flow 1100 shown in Figure 11 may be substantially the same whether only some of the group of UEs 105 are target UEs or whether all of the group of UEs 105 are target UEs. In particular, the number of target UEs 105 for the signal flow 1100 may be more than one.

[0152]

[0176] Signal flow 1100 involves the explicit establishment of an SLPP session between multiple UEs 105. An SLPP session may also be referred to as a session, a group session, an SLPP group session, an SLPP group mode session, a sidelink positioning session, or a group mode sidelink positioning session.

[0153]

[0177] In stage 1 of Figure 11, anchor UE 105A discovers UE1 105B, and vice versa. For example, discovery messages may be exchanged between UEs to determine nearby UEs that are available to participate in sidelink positioning. In some embodiments, the anchor UE (e.g., UE 105A) broadcasts a discovery request indicating anchor status and SLPP support and / or group mode SLPP support, and available nearby UEs (e.g., UE 105B) may send discovery responses (e.g., via unicast) indicating SLPP and / or group mode SLPP support. In Figure 11, for example, it is assumed that all UEs 105A, 105B, 105C, ... 105n can participate in a group mode sidelink positioning session.

[0154]

[0178] In phase 2, optionally, security establishment may be performed between UEs 105A and 105B. In some embodiments, in network-assisted UE mode, security may be established if the serving PLMN is configured with anchor UE security data (e.g., encryption keys). For example, for a first UE (e.g., one of UEs 105B, 105C, 105D, ... 105n) and an anchor UE (e.g., UE 105A), when both UEs are in PLMN coverage, proximity service security may be used for unicast SLPP messages to enable (i) encryption of unicast SLPP messages, (ii) authentication of the anchor UE by the first UE, and (iii) verification of multicast messages sent by the first UE or the anchor UE to the other party using digital signatures. In another example, if the first UE, but not the anchor UE, is within PLMN coverage, a trusted source (e.g., a local authority in the PLMN or an RSU accessible via the PLMN) can provide the first UE with a ciphering key ID and a corresponding ciphering key; for example, the anchor UE and the trusted source can use a common secret key to encrypt the ciphering key ID into a ciphering key that the first UE uses for anchor UE association. The ciphering key ID can be pseudo-random (e.g., 128 bits) assigned by the trusted source that is unique to the first UE (e.g., no two UEs use the same ciphering key ID). This can enable (i) encryption of unicast SLPP messages, (ii) authentication of the anchor UE by the first UE, and (iii) verification of multicast messages sent by the first UE or the anchor UE by other parties using digital signatures. In a further example, some secure UEs (e.g., for public safety and law enforcement) can be configured with security and key information for several classes of anchor UEs (e.g., RSUs) that can support security as in the above two examples.In some embodiments, the multicast message may be encrypted if the criteria set forth in any of the above examples are supported by all UEs participating in the group mode sidelink positioning session (also referred to as “group member UEs”), but may not be encrypted otherwise.

[0155]

[0179] In stage 3, UE 105B may provide one or more of its location, capabilities, and available resources to anchor UE 105A. For example, as shown in FIG. 11, UE 1 may transmit its current location (e.g., latitude and longitude) to the anchor UE (e.g., UE 105A) using V2X signaling. In some embodiments, the anchor UE may initiate a pairwise mode sidelink positioning session with UE 1 105B to obtain UE 1's location and SLPP capabilities and resources, as described above with respect to FIG. 8. In some embodiments, the resources may include a sidelink PRS configuration that UE 1 is already using (e.g., for other communications in other group mode sidelink positioning sessions). Thus, the anchor UE may verify that UE 1 is within an area controlled by the anchor UE and assign UE 1 to specific group(s) or subgroup(s) for the group mode sidelink positioning session, as shown in FIG. 10.

[0156]

[0180] In step 4, the anchor UE 105A decides to establish (or initiate) a session for the sidelink positioning protocol (SLPP) for the group of UEs 105. For example, the UE 105A may be configured at the application layer to establish an SLPP session for the group of UEs 105 when certain criteria for the group of UEs 105 are met, as described with reference to Figures 7 and 10. The group of UEs 105 may be determined by the anchor UE 105A without first notifying the other UEs 105, or all UEs 105 may participate in determining and forming the group of UEs 105. The UE 105A may also or alternatively decide to establish (or initiate) a session for SLPP based on a service request received from a network entity (e.g., the LMF 120 or the AMF 115), where the service request may indicate the group of UEs 105 to which the service request applies. The UE 105A may then send a request to UE 1 to join the group mode sidelink positioning session. In some embodiments, the request may include a common group address for the group mode sidelink positioning session (e.g., a Level 2 group address supported by the 3GPP physical layer and MAC sidelink protocol layer).

[0157]

[0181] In step 5, UE1 may respond to the request with an acceptance (eg, as shown in step 5a) or a rejection (eg, as shown in step 5b).

[0158]

[0182] In step 6, steps corresponding to steps 1-5 may be repeated for each of the other UEs 2-n (e.g., UEs 105C, 105D, ... 105n). In some embodiments, each of steps 1-5 may be performed using unicast.

[0159]

[0183] In step 7, the anchor UE 105A initiates the group mode sidelink positioning session by sending an initiation message (e.g., an SLPP Start Group Session message) to each of the UEs that accepted the request in step 5. In some embodiments, the anchor UE 105A may multicast the initiation message to all group member UEs (e.g., UE1, UE2, ...UEn) of the session based on a group address. In some embodiments, the initiation message includes the UE addresses (e.g., level 2 addresses and / or application level addresses or IDs) of each UE participating in the group mode SLPP session. In some embodiments, the anchor UE 105A may include a group encryption key for all of the UEs in the SLPP session, which may be used by the UEs to encrypt some or all SLPP messages sent later in steps 9, 11, 12, 14, and 15.

[0160]

[0184] In response, in step 8, each UE that receives the initiation message in step 7 may respond with an acknowledgment for receiving the initiation message (e.g., an SLPP Initiate Group Session Acknowledgement message), which may be unicast to UE 105A only or multicast to UE 105A and all other UEs in the SLPP session. In some embodiments, the acknowledgment may include data contained in the initiation message (e.g., addresses of group member UEs) and then multicast to all group member UEs. Thus, UEs that miss the initiation message may still receive the information in the initiation message (e.g., through receiving acknowledgments from other UEs). Step 8 is optional and may not necessarily be performed.

[0161]

[0185] In some embodiments, the UE address (e.g., transmitted in step 7) may include a level 2 address and / or an application level address of the UE. In some embodiments, the SLPP messages transmitted in the group mode sidelink positioning session (e.g., in steps 7, 8, 9, 11, 12, 14, 15) may include a local UE ID (used in the SLPP message), also referred to as an SLPP UE ID, for each of the group member UEs in the session. For example, each of the group member UEs may be indexed (e.g., from 0 to n), and the local (SLPP) UE ID may correspond to the UE's index. The initiation message transmitted in step 7 may indicate the correspondence of the SLPP UE ID for each group member UE to another address for that UE, such as a level 2 address or an application level address. The SLPP UE ID may be used in SLPP messages (e.g., in steps 9, 11, and 12) to identify specific UEs and information (in SLPP messages) for those UEs using fewer signaling bits than required for level 2 addresses or application level addresses, thus reducing SLPP signaling.

[0162]

[0186] In step 9, the anchor UE 105A may determine and transmit SL PRS configuration data (e.g., SL PRS configurations to be used for the group mode sidelink positioning session) to all group member UEs. For example, the SL PRS configuration data may include the SL PRS configurations to be transmitted one or more times by each UE (anchor UE, UE1, UE2, UE3, UEn). The SL PRS configurations to be transmitted by each UE may be distinct from the SL PRS configurations to be transmitted by any other UE, e.g., at least the transmission time and / or code may be different. For example, SL PRS configurations PRS0, PRS1, PRS2, PRS3, PRSn may be transmitted by the anchor UE, with the anchor UE transmitting PRS0, UE1 transmitting PRS1, UE2 transmitting PRS2, UE3 transmitting PRS3, and UEn transmitting PRSn. In some embodiments, if one of the group member UEs is already transmitting SL PRS with the anchor UE for another group (e.g., the UE is in more than one group / subgroup controlled by the anchor UE), the anchor UE may include the SL PRS configuration used for the other group as the SL PRS configuration data for that UE.

[0163]

[0187] In step 10, all group member UEs in the group mode sidelink positioning session may transmit and measure SL PRSs. For example, each group member UE in the group mode sidelink positioning session may transmit and measure SL PRSs according to the SL PRS configuration determined and transmitted by the anchor UE in step 9. For example, each UE may transmit its own SL PRS (e.g., anchor UE transmits PRS0, UE1 transmits PRS1, UE2 transmits PRS2, UE3 transmits PRS3, and UEn transmits PRSn), and all other UEs except the transmitting UE measure the transmitted SL PRS. In some embodiments, the measurements may include the received signal strength indicator (RSSI), round-trip signal propagation time (RTT), reference signal received power (RSRP), reference signal received quality (RSRQ), angle of arrival (AOA), angle of departure (AOD), time of arrival (TOA), received time-to-transmit time difference (Rx-Tx), and reference signal time difference (RSTD) of the transmitted PRS.

[0164]

[0188] In steps 11 and 12, each UE participating in the group mode sidelink positioning session can determine and transmit (to other UEs) an SLPP measurement report (or SLPP location information provision message) containing the measurements obtained in step 10. In some embodiments, the SLPP measurement report message transmitted by the UE 105 can include a modified SL PRS configuration that corresponds to the SL PRS actually transmitted by the UE 105 in step 10 and indicates the exact SL PRS configuration used by the UE 105 in step 10. For example, in the case of UE1 105B, UE1 105B receives from anchor UE 105A in step 9 an SL PRS configuration PRS1 indicating the SL PRS configuration intended to be used by UE1 in step 10, but UE1 105B may need to slightly modify this configuration in step 10 due to SL PRS transmissions or other interference from other UEs or other RF conditions. For example, UE1 105B may have changed the bandwidth or the exact time of PRS1 transmission. UE1 105B can then include the modified PRS1 configuration in the measurement report sent in step 12 indicating the change to the PRS1 configuration used to transmit PRS1 in step 10. Anchor UE 105A and the others, UE2-n, can do the same for each of their PES configurations, PRS0, PRS2, PRS3-PRSn. The measurement report may indicate the exact SL PRS transmit and receive times for the measurement and the modified SL PRS configuration using global time (e.g., GNSS or UTC time). In some embodiments, each UE may multicast an SLPP measurement report to all other group member UEs, indicating which other group member UEs it is able to receive measurement reports from. This may help anchor UE 105A determine group member changes.

[0165]

[0189] In step 13, one or more of the UEs participating in the group mode sidelink positioning session (referred to as participating UEs) determine location results for the participating UEs (e.g., for a participating UE that is a target UE), such as the range between the target UE and another participating UE, the direction from the target UE to the other participating UE, or the direction from the target UE to the other participating UE, respectively, the location of the target UE relative to the location of the other participating UE, the velocity of the target UE relative to the velocity of the other participating UE, the absolute location of the target UE, the absolute velocity of the target UE, or any combination thereof. The determined location results may then be transmitted to the other UEs for the SLPP session.

[0166]

[0190] Steps 10-13 may be repeated, for example, if this was indicated by the anchor UE 105A in step 4 or step 7.

[0167]

[0191] It should be noted that the SLPP messages sent in steps 7, 8, 9, 11, 12, 14, and 15 may be structured or partially structured as described with respect to Figures 4A and 4B, and may therefore each include one or more of a session ID, a transaction ID, a sequence number (seq no), and an acknowledgment (or acknowledgement) sequence number.

[0168]

[0192] In some embodiments, the anchor UE 105A may determine group membership changes during the session (e.g., moving a UE between different subgroups and / or assigning a UE to two or more subgroups). For example, if a UE participating in a group mode sidelink positioning session moves in / out of the anchor UE's control area (e.g., the control area of ​​groups 1015, 1025, and / or 1035 shown in FIG. 10), the anchor UE may adjust the UE's group status accordingly (e.g., reassign the UE to another group / subgroup and / or remove the UE from any group or subgroup controlled by the anchor UE). Thus, steps 7 and 8 may be repeated for those affected groups (e.g., groups with removed and / or added UEs), or signal flow 1500, described below with respect to FIG. 15, may be used.

[0169]

[0193] In steps 14 and 15 of FIG. 11, the anchor UE may terminate the group mode sidelink positioning session by multicasting a session termination request, and the group member UEs may accept the request to terminate the group mode sidelink positioning session.

[0170]

[0194] The messages described above for steps 1-6 of Figure 11 may be sent between UEs (e.g., anchor UE 105A and another UE 105) using unicast, where the message includes an address of a specific destination UE (e.g., a level 2 address). The messages described above for steps 7-15 of Figure 11 may be sent between UEs (e.g., anchor UE 105A and another UE 105) using multicast, where the message includes a group address applicable to all UEs 105 (e.g., a level 2 group address), which may allow each of UEs 105A, 105B, 105C, 105D, 105n that is not the sender of the message to receive the message.

[0171]

[0195] FIG. 12 is a signal flow illustrating signaling between UEs for a group mode sidelink positioning session for multiple UEs, sometimes collectively referred to as UEs 105, denoted as UEs 105A, 105B, 105C, ... 105n. The group of UEs may include a small number of UEs (e.g., up to 20) capable of direct discovery and direct sidelink signaling. The UEs 105 may be, for example, any of the UEs shown in FIG. 1 and the UEs shown in group 210 in FIG. 2. The sidelink positioning shown in FIG. 12 may be network-independent; therefore, the UEs shown in FIG. 12 may be out-of-coverage UEs in subgroup 216. If desired, signaling may be performed directly as shown, via relays, and / or via the network.

[0172]

[0196] In some embodiments, the group mode sidelink positioning as shown in FIG. 12 may be an extension of the group mode sidelink positioning as shown in FIG. 11, in which the role of the anchor UE may be changed and other UEs participating in the group mode sidelink positioning (e.g., group member UEs) may have more control over the positioning process.

[0173]

[0197] For example, as shown in FIG. 12, signal flow 1200 may include steps 1-5. In step 1 of signal flow 1200, mutual discovery of UEs and initial information transfer may be performed. In some embodiments, the operations in step 1 of signal flow 1200 may be similar to the operations in steps 1-3 and part of step 6 of signal flow 1100 shown in FIG. 11, except that one or more of the UEs (e.g., any of the UEs 105) may be anchor UEs. In some embodiments, the process may be performed based on proximity services or V2X services. In some embodiments, the discovery request and response message for the discovery request may indicate support for SLPP and / or group mode sidelink positioning and whether the UE is capable of acting as an anchor UE. In some embodiments, the message transmitted in step 1 of signal flow 1200 may also include IDs for all group mode sidelink positioning sessions to which each UE (e.g., any of the UEs 105) belongs and an anchor UE address for each group mode sidelink positioning session.

[0174]

[0198] In some embodiments, a UE that discovers many nearby UEs that belong to the same group for group mode sidelink positioning may then request to join the group, avoiding the need to initiate a separate group for group mode sidelink positioning. In some embodiments, a UE performing group mode sidelink positioning may also individually use pairwise mode sidelink positioning sessions to determine the range, orientation, and velocity of other UEs, as described above with respect to Figures 5 and 8, to help determine which UEs should be included in the group for group mode sidelink positioning. In some embodiments, security may also be optionally established, subject to similar restrictions as in stage 2 of signal flow 1100.

[0175]

[0199] In step 2 of signal flow 1200, a group mode sidelink positioning initiation session may be performed, which may be the same as or similar to steps 4-8 of FIG. 11, or as described below with respect to FIG. 13.

[0176]

[0200] Group mode sidelink positioning may be performed in stage 3 of signal flow 1200. In some embodiments, the operations in stage 3 of signal flow 1200 may be similar or identical to the operations in stages 9-13 of signal flow 1100 shown in Figure 11, or stages 1-11 of signal flow 700 shown in Figure 7, with the same or additional stages. Stage 3 is described in more detail below with respect to Figure 14.

[0177]

[0201] In step 4 of signal flow 1200, a group session modification may be performed to change group members (e.g., UEs participating in a group mode sidelink positioning session) and / or anchor UEs of the group. Step 4 is described in more detail below with respect to FIG. 15.

[0178]

[0202] In step 5 of signal flow 1200, a termination session may be performed to terminate the group mode sidelink positioning session. In some embodiments, the operations in step 5 of signal flow 1200 may be the same as or similar to the operations in steps 14-15 of signal flow 1100 shown in Figure 11. Step 5 is described in more detail below with respect to Figure 18.

[0179]

[0203] Figure 13 is a signal flow 1300 illustrating signaling between UEs for an initiation session of a group mode sidelink positioning session, according to one embodiment, and illustrates step 2 of Figure 12. Signal flow 1300 is similar to steps 4-5 and 7-8 of Figure 11, but includes some extensions for added flexibility.

[0180]

[0204] After mutual discovery and initial information transfer (e.g., step 1 of signal flow 1200), a UE with anchor capability (e.g., UE1 105A here) may decide to create a new group for performing group mode sidelink positioning and act as the anchor UE for group mode sidelink positioning.

[0181]

[0205] In step 1 of Figure 13, UE1 sends an SLPP session request unicast to each of the other UEs (UE2, UE3 through UEn). A level 2 group address is included in the SLPP session request. All UE addresses (e.g., level 2 addresses and / or application level addresses of UE2, 3 through n) may be included to allow each UE to know which other UEs are in the group.

[0182]

[0206] Each of the other UEs (UE2, UE3 through UEn) provides one of two responses in stage 2a or stage 2b. In stage 2a, the UE may send an accept indication to UEl for the SLPP group session, and may optionally include addresses of additional UEs that may be added to the group (e.g., the address of UEm that was not included in stage 1). Alternatively, in stage 2b, the UE may send a reject indication for the SLPP session to UEl, optionally indicating one or more existing group sessions in which UEl may participate. UEl may then join the other group session and / or terminate the new group session.

[0183]

[0207] In step 3, UE1 sends an SLPP session request unicast to each of any additional UEs (e.g., UEm) indicated in step 2a. Each of the additional UEs (e.g., UEm) can then indicate to UE1 its acceptance (step 4a) or rejection (step 4b) of the session, as in step 2, and can optionally include addresses of additional UEs that may be added to the group, as in step 2. To prevent additional UEs from being returned indefinitely (as in steps 2 and 4), the SLPP session request sent by UE1 can indicate whether the receiving UE is authorized to return addresses of additional UEs. UE1 can then disallow sending addresses of additional UEs (e.g., in step 3 or after step 4).

[0184]

[0208] UEs that accept the request in steps 2a and 4a may be included in the group mode sidelink positioning session. UEs that reject the group mode sidelink positioning session in steps 2b and 4b may be excluded from the group mode sidelink positioning session.

[0185]

[0209] At the end of stage 2 or stage 4 of signal flow 1300, anchor UE 1 initiates a group mode sidelink positioning session in stage 5, similar to how anchor UEs initiate a group mode sidelink positioning session for stage 7 of signal flow 1100. In response, in stage 6, which may be optional, each UE that receives the initiation message in stage 5 may respond with an acknowledgment for stage 8 of signal flow 1100.

[0186]

[0210] FIG. 14 is a signal flow 1400 illustrating signaling between UEs for group mode sidelink positioning, according to one embodiment, illustrating step 3 of FIG.

[0187]

[0211] 14, in step 1 of signal flow 1400, each UE participating in the group mode sidelink positioning session (e.g., a UE that accepts a request in step 2 or step 4 of signal flow 1300) transmits its sidelink positioning capabilities and resources to all other participating UEs, e.g., via multicast. Optionally, anchor UE1 may first multicast each UE's capability request to all other UEs in the group.

[0188]

[0212] In stage 2 of signal flow 1400, a common time reference may be established for making SL PRS measurements (as described in more detail below).

[0189]

[0213] In stage 3 of signal flow 1400, the anchor UE sends, e.g., via multicast, an SL PRS configuration for each group member UE of the group mode sidelink positioning session. Each UE receiving the SL PRS configuration may acknowledge receipt. In some embodiments, the acknowledgement may repeat / include all received SL PRS configurations. The SL PRS configurations transmitted in stage 3 may include, for each UE in the group (e.g., UE1, UE2, UE3, UEn), a separate SL PRS configuration to be transmitted by that UE at one or more subsequent times. The SL PRS configurations may thereby indicate the SL PRS configurations to be transmitted by each UE and the SL PRS configurations for other UEs in the group that each UE can measure. The anchor UE may also indicate measurements to be taken by each UE of the SL PRS configurations to be transmitted by the other UEs.

[0190]

[0214] In stage 4 of signal flow 1400, all group member UEs perform SL PRS transmissions and measurements according to the SL PRS configuration received in stage 3. For example, the measurements may include received signal strength indicator (RSSI), round trip signal propagation time (RTT), reference signal received power (RSRP), reference signal received quality (RSRQ), angle of arrival (AOA), angle of departure (AOD), time of arrival (TOA), received time-to-transmit time difference (Rx-Tx), and reference signal time difference (RSTD).

[0191]

[0215] In step 5 of signal flow 1400, each UE participating in the group mode sidelink positioning session multicasts a measurement report to all other UEs participating in the group mode sidelink positioning session, which may include the measurements obtained in step 4 and the modified PRS configuration used in step 3. In some embodiments, each measurement report may indicate from which UEs the UE transmitting the measurement report may be able to receive the measurement report. In some embodiments, the measurement report may also include a vote to select an anchor UE for the group mode sidelink positioning session. Steps 4 and 5 may be repeated, for example, periodically. Steps 3-5 of FIG. 14 may be similar to steps 1-11 of FIG. 7 and steps 9-13 of FIG. 11, both of which include additional details, actions, and signaling that may be used in FIG. 14.

[0192]

[0216] Figure 15 is a signal flow 1500 illustrating signaling between UEs to enable modification of an SLPP group session that may have been established as described with respect to Figure 11 or Figure 13. In Figure 15, UEs 1 through n (105A, 105B, 105C, 105n) are existing UEs that are already part of the SLPP group session, and UEs p and q (105p and 105q) are new UEs that are not yet part of the SLPP group session. Although Figure 15 shows two new UEs, there may be more than two new UEs, or fewer than two new UEs, with no new UEs.

[0193]

[0217] Modification of the SLPP session may be initiated by anchor UE1 105A or a new anchor UE (e.g., voted for by group member UEs for the SLPP positioning session and with anchor UE capability) to modify the membership of the group. For example, group membership may be modified by adding one or more new UEs to the group, removing one or more existing UEs from the group, and / or changing the anchor UE for the group. In some embodiments, the newly added UE may initially receive a group address from the anchor UE, e.g., as described below with respect to FIG. 16.

[0194]

[0218] 15, in step 1 of signal flow 1500, after determining the modified members of the group, anchor UE1 multicasts a group session modification request message to all other current group member UEs indicating the addresses of all group member UEs to be included in the modified group (which may include both current group member UEs and new group member UEs) and identifying the anchor UEs of the group (e.g., existing anchor UEs or newly modified anchor UEs). The group session modification request message may include the current SLPP session ID, a new SLPP session ID to be used for the modified SLPP session, and / or a new SLPP UE ID for each of the modified group member UEs to be used for the modified SLPP session.

[0195]

[0219] In stage 2, each of the other group member UEs multicasts (or unicasts) an acceptance (stage 2a) or a rejection (stage 2b) in response to receiving the group session modification request. In some embodiments, the acceptance or rejection includes the addresses of all new group member UEs and identifies the anchor UE. In some embodiments, if a rejection is sent (e.g., as shown in stage 2b of signal flow 1500) or if no response is sent, the member UE may be removed from the modified group.

[0196]

[0220] In an optional embodiment, the group session modification request is sent in stage 2 only to UEs to be included in the modified group session, and not to UEs to be excluded from the modified group session. In this embodiment, in stage 3, anchor UE1 multicasts an SLPP session termination request to all UEs to be excluded from the modified group session, or unicasts a separate SLPP session termination request to each UE to be excluded from the modified group session. Each UE to be excluded from the modified group session then returns an SLPP session termination accept to anchor UE1 105A.

[0197]

[0221] If there is at least one new UE to be added to the modified group session, in step 5, anchor UE1 unicasts an SLPP session request to each of the new UEs (UEp and UEq in the example of Figure 15). Each new UE then returns an SLPP session accept (step 6a) or session reject (step 6b) to anchor UE1. New UEs that return a session reject or do not respond are not included in the modified session. Note that for any new UEs requesting to join the group session according to signal flow 1600, described next with reference to Figure 16, steps 5 and 6 are not performed, as signal flow 1600 makes steps 5 and 6 unnecessary for such new UEs.

[0198]

[0222] In step 7, the anchor UE 1 performs an initiation session to initiate the modified SLPP group session. The initiation may be as described for steps 7 and 8 of FIG.

[0199]

[0223] Figure 16 is a signal flow 1600 illustrating signaling between UEs for joining a group mode SLPP session, according to one embodiment. As shown in Figure 16, in stage 1 of signal flow 1600, mutual discovery may be performed by new UE 105r (e.g., not currently a group member UE) and a group member UE (e.g., exemplary UE1 in Figure 16). For example, new UE 105r may discover group member UE1 (or vice versa), and group member UE1 may provide the new UE with a group session ID (e.g., an SLPP session ID) and an anchor UE address (e.g., a level 2 address and / or an application level address).

[0200]

[0224] In stage 2 of signal flow 1600, new UE 105r may perform a formal discovery procedure with the anchor UE based on the anchor UE address received in stage 1. In some embodiments, there may be some sidelink positioning session (e.g., as in FIG. 8) to allow both UEs to verify their range, heading, and velocity.

[0201]

[0225] In step 3 of the signal flow 1600, the new UE 105r unicasts a join session request to the anchor UE.

[0202]

[0226] In stage 4 of signal flow 1600, anchor UE 105A may either accept the request (e.g., respond with an accept message as shown in stage 4a) or reject it (e.g., respond with a reject message as shown in stage 4b). In some embodiments, the accept message includes details about the group mode sidelink positioning session (e.g., including the level 2 group address and possibly addresses of other group member UEs).

[0203]

[0227] In stage 5 of signal flow 1600, anchor UE 105A may perform a group session modification as shown in FIG. 15 after a predetermined period of time (e.g., after several other UEs have requested to join or leave the group) to collectively process all join and / or leave requests. Either or both of the requests and responses sent in stages 3 and 4 may include a time parameter indicating when the anchor UE is expected to perform the group session modification in stage 5. For example, this may help anchor UE 105A know when new UE 105r will join the group session and may help anchor UE 105A by indicating how long the new UE can wait to join the group session.

[0204]

[0228] Figure 17 is a signal flow 1700 illustrating signaling between UEs for leaving a group mode SLPP session, according to one embodiment. When an existing group member UE 105s, referred to as the "leaving UE," decides to leave the group session (e.g., if it is currently away from other group members), as shown in Figure 17, in stage 1 of signal flow 1700, the leaving UE 105s unicasts a session leave request to the anchor UE 105A, and may include a requested time for the session leave to take effect.

[0205]

[0229] In stage 2 of the signal flow 1700, the anchor UE 105A returns an acceptance, indicating the time at which leaving the session becomes effective, which may include a time that is the same or different from the time proposed by the leaving UE 105s in stage 1.

[0206]

[0230] In stage 3 of signal flow 1700, anchor UE 105A may perform group session modification as shown in FIG. 15 to collectively process all join and / or leave requests after a predetermined period of time (e.g., after several other UEs have requested to join or leave the group). The time at which stage 3 is performed may be included by anchor UE 105A in stage 2.

[0207]

[0231] In some embodiments, the leaving UE 105s may leave the group if an acceptance of the leave request is not received from the anchor UE 105A or if the UE 105s is unable to receive other SLPP messages for the group mode sidelink positioning session from the anchor UE 105A. The anchor UE 105A may assume that an existing group member UE has left after failing to receive SLPP measurement reports from the existing group member UE for a predetermined period of time.

[0208]

[0232] Figure 18 is a signal flow 1800 illustrating signaling between UEs for terminating a group mode sidelink positioning session, according to one embodiment, and illustrates stage 5 of Figure 12. When the anchor UE 105A decides to terminate the group mode sidelink positioning session (e.g., due to problems exchanging SLPP messages with group members), as shown in Figure 18, in stage 1 of the signal flow 1800, the anchor UE 105A may multicast a request to terminate the group mode SLPP session to all other UEs in the session.

[0209]

[0233] In stage 2 of signal flow 1800, each of the other group member UEs may multicast an accept (e.g., as shown in stage 2a of signal flow 1800) or a reject (e.g., as shown in stage 2b of signal flow 1800). For UEs that accept the request, the accepting UEs leave the group mode sidelink positioning session. For those UEs that reject the request, the rejecting UEs may remain group member UEs. In some embodiments, the rejecting UEs include a vote for the new anchor UE in the rejection. Then, if more than one UE remains a group member UE (e.g., rejected the request), the UE with the most votes performs the group session modification as shown in FIG. 15.

[0210]

[0234] It should be noted that SLPP messages transferred between UEs (e.g., in Figures 5, 7, 8, 9, and 11-18) may include a session identifier (ID) (also referred to as session identification information) to identify the SLPP session to the UEs participating in the session, which may enable these UEs to recognize SLPP messages applicable to the SLPP session. For example, the anchor UE may assign a session ID and provide the session ID to other UEs participating in the SLPP session. Some SLPP messages shown as being transferred between UEs for an SLPP session may, in some embodiments, be replaced by messages for a supplementary services protocol, such as the protocol defined in 3GPP Technical Specification (TS) 24.080. This may allow a larger number of parameters to be included, which may not be possible or suitable for a positioning protocol such as SLPP. As an example, the SLPP session request and acceptance described with respect to FIG. 9, the SLPP initiated group session and its response described with respect to FIG. 11, and the SLPP group session modification request and response described with respect to FIG. 15 may each be replaced by similar messages for the supplementary services protocol (which may also include one or more embedded SLPP messages).

[0211]

[0235] The previous descriptions (e.g., for FIGS. 11-18) assume that, to perform SL positioning for a group of UEs, a session or SLPP session is first established between all UEs in the group, or between all UEs in the group that accept the establishment of the session. SL positioning is then performed by exchanging SLPP messages between UEs in the group that belong to and are part of the session. However, establishing and later modifying and / or terminating an SLPP session requires the exchange of additional SLPP messages to establish, modify, and / or terminate SLPP sessions that are not directly used for positioning. In addition, UEs that are not part of the SLPP session will be excluded from the positioning, even if they are near UEs that belong to the session and could usefully contribute to the SL positioning. To reduce the amount of SLPP signaling required to perform SL positioning and allow all UEs that are near each other to participate in the SL positioning, an alternative session-less mode of SLPP may be used when there is no SLPP session between UEs participating in the SL positioning. The SLPP session-less mode may also avoid the need for UEs to discover each other, which further reduces the amount of signaling, allows SL positioning to be performed with reduced latency, and allows a larger number of UEs to perform SL positioning with each other compared to using an SLPP session. The SLPP session-less mode can be likened to having an SLPP session that includes all UEs and is permanently established without requiring any signaling for establishment or termination. A special reserved session ID can be included in SLPP messages sent for the SLPP session-less mode to indicate the session-less mode.

[0212]

[0236] FIG. 19 shows a signal flow 1900 illustrating SL positioning for a session-less mode of SLPP, also referred to as broadcast mode sidelink positioning or non-session-based sidelink positioning, for multiple UEs, denoted as UEs 105A, 105B, and 105C, which may be collectively referred to as UEs 105. The UEs 105 may be, for example, any of the UEs shown in FIG. 1 and the UEs shown in group 210 shown in FIG. 2. The sidelink positioning shown in FIG. 19 may be network-independent; therefore, the UEs shown in FIG. 19 may be out-of-coverage UEs in subgroup 216. The signaling performed in signal flow 1900 may be similar to or the same as the SLPP signaling described above with reference to FIG. 2. Note that although only three UEs 105 are shown in FIG. 19, the technique shown in FIG. 19 may be performed by any number of UEs greater than two, including hundreds or even thousands of UEs 105 (e.g., for SL positioning for V2X on busy highway(s)). 19, it is not necessary for the different UEs 105 to discover each other, and no SLPP session may be established between any of the UEs 105. Note also that while only some of the UEs 105 may be target UEs, it is also possible that all UEs 105 are target UEs.

[0213]

[0237] Each UE 105 shown in FIG. 19 may decide to perform SL positioning for SLPP session-less mode based on receiving an SLPP message indicating session-less mode SLPP positioning from another UE (e.g., in stages 1 and 3 of FIG. 19) or based on determining that the number of nearby UEs is too large to effectively support SLPP in session-less mode. Based on such a determination, and as shown in stage 1 of signal flow 1900, each UE 105 broadcasts an SLPP Assistance Data message. In some embodiments, the SLPP Assistance Data message transmitted by the UE includes a sidelink PRS configuration to be transmitted by the UE, an expected time of sidelink PRS transmission from the UE (according to the sidelink PRS configuration), and, optionally, sidelink PRS configuration data received from other UEs 105. The sidelink PRS configuration may indicate a frequency range or band, coding, bandwidth, duration of transmission, periodicity of transmission, and / or other parameters intended to be used by the transmitting UE 105 for the SL PRS transmitted in stage 2. In some embodiments, a UE may indicate a different transmission time and / or a different (e.g., orthogonal) code than other UEs. Different (e.g., orthogonal) codes may allow for several simultaneous transmissions by multiple UEs. In some embodiments, the SL PRS transmission time indicated in the SLPP Assistance Data message may be indicated using a common time (e.g., GNSS) or may be relative to the transmission time for the SLPP Assistance Data message. The SLPP Assistance Data message may also include a Level 2 address and / or an application level address of the transmitting UE 105. The SLPP Assistance Data message may be broadcast by the UE 105 to all other UEs 105 that are capable of receiving the message and may not be transmitted using unicast or multicast.

[0214]

[0238] In stage 2 of signal flow 1900, each UE 105 broadcasts SL PRS according to the SL PRS configuration transmitted by the UE 105 in stage 1 (e.g., using an Intelligent Transport System (ITS) spectrum, an unlicensed spectrum, or a PLMN operator spectrum) and measures the SL PRS being broadcast by other UEs. For example, the measurements may include one or more of the following: Received Signal Strength Indicator (RSSI), Round Trip Signal Propagation Time (RTT), Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), Angle of Arrival (AOA), Angle of Departure (AOD), Time of Arrival (TOA), Received Time-Transmit Time Difference (Rx-Tx), and Reference Signal Time Difference (RSTD). The measurements may be based on the sidelink PRS configuration and the expected time of the sidelink PRS transmission received from other UEs in stage 1. Each UE also records its own SL PRS transmission time and the time the SL PRS was received from other UEs as timestamps t in FIG. 19 . ij (i, j=1, 2, or 3).

[0215]

[0239] In stage 3 of signal flow 1900, each of the UEs 105 broadcasts an SLPP Measurement Report message containing measurements (e.g., Rx-Tx) obtained in stage 2 for the SL PRS received from other UEs 105 and / or containing recorded timestamps. In some embodiments, the SLPP Measurement Report message transmitted by the UE 105 may contain a modified SL PRS configuration corresponding to the SL PRS already transmitted by the UE 105 in stage 2 and indicating the exact SL PRS configuration used by the UE 105 in stage 2. For example, the UE 105 may have already transmitted an SL PRS configuration in stage 1 indicating a configuration intended to be used later in stage 2, but the UE 105 may have changed this configuration due to SL PRS transmissions from other UEs, interference, or other RF conditions. For example, the UE 105 may have changed the bandwidth or exact time of the PRS transmission.

[0216]

[0240] A UE 105 receiving and measuring an SL PRS in stage 2 may identify the SL PRS transmission and determine which UE 105 sent any SL PRS transmission by matching the received and measured SL PRS configuration with the intended SL PRS configuration received in stage 1 or (preferably) the modified SL PRS configuration received in stage 3. For example, the SL PRS frequency, bandwidth, coding, transmission duration, and transmission time may be matched. Thus, as an example, if UE1 105A receives and measures an SL PRS with a particular SL PRS configuration in stage 2, and UE2 105B (but no other UEs) indicates in stage 1 or stage 3 that the exact same SL PRS configuration is about to be transmitted or has already been transmitted by UE2 105B, respectively, UE1 105A may assume that the SL PRS it received and measured was transmitted by UE2 105B and not some other UE.

[0217]

[0241] The SL PRS transmission times may be indicated using global time, which may be a mapping from the UE local time or may be UTC or GNSS time. The SLPP Measurement Report message may include the level 2 address and / or application level address of the transmitting UE 105 and the level 2 address and / or application level address for each UE 105 for which SL PRS measurements are included in the SLPP Measurement Report message.

[0218]

[0242] In stage 4, one or more of the UEs 105 (e.g., each of the UEs 105) determine a location result for the UE 105 that is the target UE (which could be, for example, all of the UEs 105). The location result may include the RTT between the pair of UEs 105, the range between the target UE 105 and another UE 105, the direction from the target UE 105 to or from another UE 105, respectively, the location of the target UE 105 relative to the location of the other UE 105, the velocity of the target UE 105 relative to the velocity of the other UE 105, the absolute location of the target UE 105, the absolute velocity of the target UE 105, or some combination thereof. The location result may be determined in stage 4 by any UE 105 based on one or more of the measurements and modified SL PRS configurations received from the other UEs 105 in the SLPP Measurement Report message in stage 3, the SL PRS measurements obtained by the UE 105 in stage 2, and the modified SL PRS configuration for the UE 105 sent by the UE in stage 3.

[0219]

[0243] In step 5, the UE 105 may optionally transmit the location results obtained in step 4 to other UEs 105. In that case, the SLPP message transmitted in step 5 may include the level 2 address and / or application level address of the transmitting UE 105 and the level 2 address and / or application level address for each UE 105 for which the location results are included.

[0220]

[0244] Note that the SLPP messages transmitted in stages 1, 3, and 5 may be structured or partially structured as described with respect to Figures 4A and 4B and may therefore each include one or more of a session ID, a transaction ID, a sequence number (seq no), and an acknowledgment (or acknowledgement) sequence number. The session ID may be a reserved value indicating that the SLPP message is being used for SLPP session-less mode. Alternatively, the SLPP header for each SLPP message may indicate session-less mode in some other manner, for example, using a separate parameter or flag in the SLPP message header. It may be important that the SLPP messages transmitted in stages 1, 3, and 5 indicate session-less mode so that the receiving UE can associate these SLPP messages with the procedure shown in Figure 19 and know that session-less mode is being used by other UEs.

[0221]

[0245] In some embodiments for V2X support, when performing signal flow 1900, the broadcast of SLPP assistance data in stage 1, measurement report messages in stage 3, and location results in stage 5 may be transmitted over the ITS spectrum, while SL PRS signals are transmitted in the unlicensed spectrum. In some embodiments, the UE 105 may include a Level 2 address and application identity in the SLPP messages to allow location measurements and locations to be associated with specific UEs that may be tracked over a period of time. The identity of the UE 105 may correspond to the identity of the UE 105 used by these UEs 105 for other V2X communications. When there is congestion (e.g., as indicated to the UE 105 by higher interference levels and / or more detected SL PRS transmissions from other UEs), the UE 105 may reduce the frequency with which it transmits SLPP messages (e.g., in stages 1, 3, and 5) and the frequency or overall amount of SL PRS transmissions in stage 2.

[0222]

[0246] In an open environment (e.g., in the case of signal flow 1900), security establishment may not be performed. However, UEs 105 can still hide their global identity, which may only be provided to some other UEs after undergoing PLMN-controlled proximity services or VX security procedures or after authenticating another UE's status (e.g., being a registered user or UE for ITS). In signal flow 1900, for example, each UE 105 can provide a temporary (e.g., application-level) ID in the SLPP messages sent in stages 1, 3, and 5, which, in the case of V2X, can be used for the duration of a road movement by the UE 105 and then changed for any new road movement. In signal flow 1900, UEs 105 may not exchange SLPP capabilities and resources. Instead, definitions (e.g., in 3GPP TS or ITS standards) can define a minimum core set of positioning capabilities that all UEs must support to participate in session-less mode sidelink positioning.

[0223]

[0247] For example, when performing step 1 of signal flow 1900, a common time reference may be established, where UE 105 may know exactly when to transmit SL PRS and when to perform SL PRS measurements.

[0224]

[0248] In some embodiments, a common time reference may be established based on the use of UTC or GPS / GNSS time, assuming that all UEs 105 are able to obtain GNSS time from navigation signals received from a global navigation satellite system (GNSS), such as GPS, Galileo, GLONASS, or Beidou.

[0225]

[0249] In some other embodiments, the common time reference may be established based on the use of RSUs with RSU time synchronized with each other and / or aligned with UTC / GNSS (e.g., if the RSUs can obtain timing from GNSS).

[0226]

[0250] In some embodiments, the common time reference may be established based on the use of local timestamps for each UE. For example, during a transmission (e.g., in stage 1, stage 3, and / or stage 5 in signal flow 1900), a first UE may include a timestamp indicating the first UE local time at which a particular portion of any transmission from the first UE (e.g., the first bit or first octet of the transmission) was transmitted (or should have been transmitted). The second UE may then calculate the real time difference (RTD) between its own local time and the local time indicated by the first UE. The RTD may be equal to the local time indicated by the first UE plus an estimated propagation delay from the first UE to the second UE minus the local time at the second UE at which the particular portion of the transmission from the first UE is received. Alternatively, the RTD may be calculated as the negative of this addition and subtraction. In some cases, the propagation delay between pairs of UEs may be ignored (i.e., assumed to be 0) in this addition and subtraction, since the propagation delay is typically very small (e.g., less than 1 microsecond for most V2X UE pairs). Each UE can then include a timestamp and transmission time according to its own local time in the SLPP message, which any other UE can convert to its own local time (by adding or subtracting the RTD between the pair of UEs).

[0227]

[0251] In some embodiments, a common time reference can be established based on the use of a group RTT procedure. For example, one source UE (at a time) multicasts or broadcasts an SLPP RTT request message to the other UEs, including a local transmit time (stamp) for that UE. Each of the other UEs responds at a different time with an RTT response message, including a local time (for each UE) indicating the local time the SLPP RTT request message was received and a local transmit time (stamp) (for each UE) indicating the local time at which the RTT response message should have been sent. The source UE then determines the RTT and RTD to the other UEs. This can enable very accurate time synchronization and can be part of the SLPP RTT / AoA procedure for establishing range and bearing. This procedure can be extended to all UEs by having all UEs send one set of RTT requests first, followed by another set of RTT responses, each including a local transmit time (stamp) and a local receive time indicating when each of the RTT requests was received by the sending UE.

[0228]

[0252] In some embodiments, SL PRS measurements may be reported based on a common time reference. For example, each UE may maintain an accurate local time X for that UE with low time drift (e.g., may use the RSU / gNB as a clock source). The UE may also maintain a separate common time reference T (e.g., based on GNSS / UTC) with lower accuracy (e.g., on the order of 10 μs). The common time reference T may be used to schedule SL PRS transmissions and measurements and to report when the SL PRS is transmitted and when it is measured (timestamps). The UE may also report TOA measurements and times of SL PRS transmissions using the common time reference T. While the accuracy for the common reference may be low (e.g., 10 μs error), the precision and accuracy for the local UE time X may be high. For example, assume that a UE has a set of local transmit and receive times, e.g., X1, X2, X3, ..., to report. Xn, the UE can convert these times to corresponding common times T1, T2, T3, ... Tn is transmitted via some fixed conversion algorithm (e.g., T = aX + b) that maintains high accuracy of local transmit time and local receive time. Thus, the common time provides an accuracy of, for example, about 10 μs, but the difference between the common times (e.g., for RSTD or Rx-Tx) can be much more accurate than any common error in the common times T1, T2, T3, .... Tn is cancelled out and removed by using the difference between the common times. This can help other UEs determine the source UE for SL PRS measurements and enable accurate Rx-Tx and RSTD calculations. Therefore, this scheme can be used even when a UE has a high error in its common time T.

[0229]

[0253] The descriptions of sidelink and SLPP positioning up to this point have not indicated a specific SLPP positioning method or have assumed and referenced positioning based on SL PRS transmission and measurement by participating UEs. However, the procedures for SL and SLPP positioning and related architectures described herein need not employ SL PRS transmission and measurement by participating UEs; instead, other positioning methods can be used. These may, in some embodiments, be radio access technology (RAT)-independent positioning methods. These other positioning methods may include real-time kinematics (RTK), transmission and measurement by participating UEs, transmission and measurement of WiFi signals by participating UEs, and transmission and measurement of ultra-wideband (UWB) signals by participating UEs. For example, when sidelink positioning of multiple UEs is performed using RTK, each UE of the multiple UEs may measure and obtain carrier phase measurements of global navigation satellite (GNSS) signals (e.g., for GPS, Galileo, GLONASS, or Beidou). The carrier phase measurements acquired by the multiple UEs may then be provided to at least one of the multiple UEs, where the at least one UE determines a location result for the multiple UEs based on the carrier phase measurements acquired by the multiple UEs. Using RTK rather than SL PRS may have little or no effect on how SLPP sessions are established, modified, and terminated in the cases of Figures 11-18. However, it is no longer necessary to transmit the SL PRS configuration to be transmitted or measured to the other UEs; instead, other assistance data may be transmitted to the UE, such as configurations to be transmitted or measured for WiFi or UWB signals, or details of GNSS signals to be measured (but not transmitted) for RTK. Also, it is no longer necessary to transmit and measure SL PRS; instead, either WiFi or UWB signals may be transmitted and measured, or, in the case of RTK, RTK signals may be measured (but not transmitted). These changes require modifications to steps 9-13 of Figure 11, steps 3 and 4 of Figure 14, and steps 1-4 of Figure 19.With these modifications, each of the signal flows 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800 and 1900 may remain valid for these other positioning methods.

[0230]

[0254] 20 is a flow diagram of a method 2000 for supporting sidelink positioning for a plurality of UEs and performed by a UE (e.g., UE 105) of the plurality of UEs, according to one embodiment. The UE may comprise an anchor UE, a cooperating UE, or another UE, as described herein. Example components of a UE are provided below with respect to FIGS. 23 and 24.

[0231]

[0255] In block 2010, the functions include initiating or joining a sidelink positioning session, the sidelink positioning session including a session for a Sidelink Positioning Protocol (SLPP) between all of the plurality of UEs, the sidelink positioning session enabling the exchange of SLPP messages between all of the plurality of UEs. Means for performing the functions of block 2010 may include the bus 2305, the processor 2310, the DSP 2320, the wireless communication interface 2330, the memory 2360, the GNSS receiver 2380, and / or other components of the UE, as illustrated in FIG. 23 .

[0232]

[0256] In block 2020, the functions include obtaining location measurements (e.g., Rx-Tx, RSTD, RSSI, RTT, RSRP, RSRQ, AOA, AOD, or time of arrival (ToA) measurements) for signals transmitted by other UEs of the plurality of UEs or transmitted by other sources (e.g., GNSS SVs). Means for performing the functions of block 2020 may include bus 2305, processor 2310, DSP 2320, wireless communication interface 2330, memory 2360, GNSS receiver 2380, and / or other components of the UE, as illustrated in FIG. 23 .

[0233]

[0257] In block 2030, the function includes transmitting location measurements to other UEs of the plurality of UEs using a sidelink positioning session. Means for performing the function of block 2030 may include the bus 2305, the processor 2310, the DSP 2320, the wireless communication interface 2330, the memory 2360, the GNSS receiver 2380, and / or other components of the UE, as illustrated in FIG.

[0234]

[0258] In block 2040, the function includes receiving a second location measurement from another UE of the plurality of UEs using a sidelink positioning session. Means for performing the function of block 2040 may include the bus 2305, the processor 2310, the DSP 2320, the wireless communication interface 2330, the memory 2360, the GNSS receiver 2380, and / or other components of the UE as illustrated in FIG. 23 .

[0235]

[0259] In block 2050, the function includes determining location results for the plurality of UEs based in part on the location measurement and the second location measurement. Means for performing the function of block 2050 may include bus 2305, processor 2310, DSP 2320, wireless communication interface 2330, memory 2360, GNSS receiver 2380, and / or other components of the UE, as illustrated in FIG.

[0236]

[0260] In some embodiments, the location measurement and the second location measurement each comprise a radio access technology (RAT) independent location measurement, a RAT dependent location measurement, or both.

[0237]

[0261] In some embodiments, the RAT independent location measurements include at least one of GNSS carrier phase measurements, GNSS code phase measurements, sensor measurements, or some combination thereof.

[0238]

[0262] In some embodiments, the RAT dependent location measurements include measurements of a first sidelink PRS occasion transmitted by another UE of the plurality of UEs.

[0239]

[0263] In some embodiments, the method 2000 further includes transmitting a second sidelink PRS occasion. The second location measurements may comprise measurements of the second sidelink PRS occasion obtained by other UEs of the plurality of UEs.

[0240]

[0264] In some embodiments, the method 2000 further includes receiving a first sidelink PRS occasion, and wherein obtaining location measurements includes measuring the first sidelink PRS occasion.

[0241]

[0265] In some embodiments, the method 2000 further includes obtaining a PRS configuration, the PRS configuration including a PRS configuration for at least the first sidelink PRS occasion or the second sidelink PRS occasion.

[0242]

[0266] In some embodiments, the method 2000 further includes: sending a session request message to each UE of the second plurality of UEs, the second plurality of UEs including other UEs of the plurality of UEs; receiving a session response message from each UE of the second plurality of UEs, the session response message including a session accept message when the respective UE agrees to participate in the sidelink positioning session and a session reject message when the respective UE does not agree to participate in the sidelink positioning session; and including each UE of the second plurality of UEs in the sidelink positioning session when the session accept message is received from each UE.

[0243]

[0267] In some embodiments, the method 2000 further includes discovering each UE of the second plurality of UEs; receiving an indication from each UE of the second plurality of UEs that the each UE supports sidelink positioning; and, in response at least in part to receiving the indication that the each UE supports sidelink positioning, sending a session request message to each UE of the second plurality of UEs.

[0244]

[0268] In some embodiments, when method 2000 is performed for group mode sidelink positioning, the method further includes including a group address in a session request message sent to each UE of the second plurality of UEs; receiving a session accept message from each other UE of the plurality of UEs; receiving a session reject message or no session response message from all UEs of the second plurality of UEs that are not part of the plurality of UEs; and sending a group session start message using sidelink multicast to the other UEs of the plurality of UEs using the group address, the group session start message including at least one address or identification information for each of the other UEs of the plurality of UEs.

[0245]

[0269] In some embodiments, the method 2000 further includes receiving a group session start acknowledgement message from each other UE of the plurality of UEs using sidelink unicast or sidelink multicast, the group session start acknowledgement message acknowledging receipt of the group session start message.

[0246]

[0270] In some embodiments, the group session start acknowledgement message is received from each other UE of the plurality of UEs using group address-based sidelink multicast, and the group session start acknowledgement message includes at least one address or identification information for each other UE of the plurality of UEs.

[0247]

[0271] In some embodiments, when method 2000 is performed for group mode sidelink positioning, method 2000 further includes resuming the sidelink positioning session with a third plurality of UEs including the UE, where resuming the sidelink positioning session includes adding additional UEs to the sidelink positioning session, removing existing UEs from the sidelink positioning session, or both, where the third plurality of UEs includes the additional UEs when the additional UEs are added, excludes existing UEs when the existing UEs are removed, or includes multiple UEs excluding the existing UEs.

[0248]

[0272] In some embodiments, when method 2000 is performed for group mode sidelink positioning, method 2000 further includes: discovering each of the additional UEs as the additional UEs are added; receiving an indication of support for sidelink positioning from each of the additional UEs as the additional UEs are added; sending a session request message including a group address to each of the additional UEs as the additional UEs are added; receiving a session accept message from each of the additional UEs as the additional UEs are added; and sending a group session initiation message using sidelink multicast to other UEs of the third plurality of UEs using the group address, the group session initiation message including at least one address or identification information for each of the other UEs of the third plurality of UEs.

[0249]

[0273] In some embodiments, when method 2000 is performed for group mode sidelink positioning, method 2000 further includes receiving a group session start acknowledgement message from each other UE of the third plurality of UEs using sidelink unicast or multicast, the group session start acknowledgement message acknowledging receipt of the group session start message.

[0250]

[0274] In some embodiments, when method 2000 is performed for group mode sidelink positioning, a group session start acknowledgement message is received from each of the other UEs of the third plurality of UEs using group address-based sidelink multicasting, and the group session start acknowledgement message includes at least one address or identification information for each of the other UEs of the third plurality of UEs.

[0251]

[0275] In some embodiments, when method 2000 is performed for group mode sidelink positioning, the session accept message received from a UE of the second plurality of UEs includes an address of the additional UE. Method 2000 further includes: sending a session request message to at least one UE of the additional UEs based on the address of the at least one UE in the session accept message; receiving a session response message from the at least one UE, the session response message including a session accept message when the at least one UE agrees to participate in the sidelink positioning session and a session reject message when the at least one UE does not agree to participate in the sidelink positioning session; and including the at least one UE in the sidelink positioning session when the session accept message is received.

[0252]

[0276] In some embodiments, when method 2000 is performed for group mode sidelink positioning, the session reject message received from a UE of the second plurality of UEs includes an indication of at least one other sidelink positioning session, and the method further includes joining the at least one other sidelink positioning session.

[0253]

[0277] In some embodiments, when method 2000 is performed for group mode sidelink positioning, method 2000 further comprises modifying the sidelink positioning session, wherein modifying the sidelink positioning session comprises identifying additional UEs to be added to the sidelink positioning session, identifying a first UE of the plurality of UEs to be removed from the sidelink positioning session, identifying a second UE of the plurality of UEs to be retained in the sidelink positioning session, sending a group session modification request message using sidelink multicast to the second UE and optionally to the first UE of the plurality of UEs, and sending a session request message using sidelink multicast to a first subset of the additional UEs, wherein the group session modification request message includes at least one address or identification for each of the second UEs of the plurality of UEs, the first subset of the additional UEs having previously requested to participate in the sidelink positioning session and excluding the second subset of additional UEs including UEs that have been accepted for the sidelink positioning session.

[0254]

[0278] In some embodiments, when the method 2000 is performed for group mode sidelink positioning, modifying the sidelink positioning session comprises (i) receiving, from each of a second UE of the plurality of UEs, a group session modification response message, the group session modification response message including a group session modification accept message when the UE agrees to participate in the modified sidelink positioning session, and a group session modification reject message when the UE does not agree to participate in the modified sidelink positioning session; and (ii) receiving, from each of a first subset of the additional UEs, a session response message, the session response message including a session accept message when the UE agrees to participate in the modified sidelink positioning session, and a session reject message when the UE does not agree to participate in the modified sidelink positioning session. (iii) identifying a third plurality of UEs to be included in the modified sidelink positioning session, the third plurality of UEs including a second UE of the plurality of UEs from which the group session modification accept message was received, UEs in a first subset of additional UEs from which the session accept message was received, and UEs in a second subset of additional UEs; (iv) transmitting, using sidelink multicast to the third plurality of UEs using the group address, a group session start message, the group session start message including at least one address or identification information for each UE of the third plurality of UEs; and (v) receiving, using sidelink unicast or multicast, a group session start acknowledgement message from each UE of the third plurality of UEs, the group session start acknowledgement message acknowledging receipt of the group session start message.

[0255]

[0279] In some embodiments, when method 2000 is performed for group mode sidelink positioning, identifying the second subset of additional UEs to be added to the sidelink positioning session comprises receiving, from each UE in the second subset of additional UEs, a request to join the sidelink positioning session using sidelink unicast, and sending, to each UE in the second subset of additional UEs, a response indicating that each UE in the second subset of additional UEs may participate in the sidelink positioning session using sidelink unicast.

[0256]

[0280] In some embodiments, when method 2000 is performed for group mode sidelink positioning, identifying first UEs to be removed from the sidelink positioning session comprises receiving, from each of the first UEs, a request to leave the sidelink positioning session using sidelink unicast, and sending, to each of the first UEs, a response indicating that each of the first UEs may leave the sidelink positioning session using sidelink unicast.

[0257]

[0281] 21 is a flow diagram of a method 2100 for supporting sidelink positioning of a plurality of UEs (e.g., UE 105) and performed by one of the plurality of UEs, according to one embodiment. Exemplary components of the UE are provided below with respect to FIGS. 23 and 24.

[0258]

[0282] In block 2110, the function includes determining sessions for a Sidelink Positioning Protocol (SLPP) for a plurality of UEs, the sessions being indicated to each UE of the plurality of UEs, e.g., as described for steps 4-6 of FIG. 11 .

[0259]

[0283] The means for performing the functions of block 2110 may include a bus 2305, a processor 2310, a DSP 2320, a wireless communication interface 2330, a memory 2360, a GNSS receiver 2380, and / or other components of the UE, as illustrated in FIG. 23.

[0260]

[0284] In block 2120, the function includes exchanging a plurality of SLPP messages with other UEs of the plurality of UEs, the SLPP messages being part of a session, the SLPP messages enabling sidelink positioning, e.g., as described with respect to steps 7-13 of FIG. 11 .

[0261]

[0285] The means for performing the functions of block 2120 may include a bus 2305, a processor 2310, a DSP 2320, a wireless communication interface 2330, a memory 2360, a GNSS receiver 2380, and / or other components of the UE, as illustrated in FIG. 23.

[0262]

[0286] In some embodiments, the method 2100 further includes obtaining location results for at least two target UEs of the plurality of UEs, the location results including at least one of a range between each target UE and another UE of the plurality of UEs, a direction to or from each target UE, respectively, to or from another UE of the plurality of UEs, a location of each target UE relative to a location of another UE of the plurality of UEs, a velocity of each target UE relative to a velocity of another UE of the plurality of UEs, an absolute location of each target UE, an absolute velocity of each target UE, or some combination thereof.

[0263]

[0287] In some embodiments, the plurality of SLPP messages include at least one SLPP message sent by a transmitting UE to a receiving UE or receiving group of UEs, where the UE is either the transmitting UE, the receiving UE, or part of the receiving group of UEs, and the at least one SLPP message includes SLPP capabilities of the transmitting UE, a request for SLPP capabilities of the receiving UE or receiving group of UEs, SLPP assistance data to assist the receiving UE or receiving group of UEs in transmitting or measuring positioning-related signals, a request for SLPP assistance data from the receiving UE to assist the transmitting UE in transmitting or measuring positioning-related signals, a request for some or both of measurements or location results obtained by the receiving UE or receiving group of UEs, some or both of measurement results or location results obtained by the transmitting UE, or some combination thereof.

[0264]

[0288] In some embodiments, the method 2100 further includes discovering each of the other UEs of the plurality of UEs, receiving an indication from each of the other UEs of the plurality of UEs that each of the other UEs supports SLPP, and determining to initiate a session based on a service request received from a network entity or a configuration of the UE, e.g., as described for steps 1 and 4 of FIG. 11 .

[0265]

[0289] In some embodiments, the method 2100 further includes each UE sending a first SLPP message to each of the other UEs of the plurality of UEs including a request to join the session, and receiving a second SLPP message from each of the other UEs of the plurality of UEs indicating acceptance or rejection of the request, e.g., as described for steps 4 and 5 of FIG. 11 .

[0266]

[0290] In some embodiments, the method 2100 further includes including at least one of a Level 2 group address of the plurality of UEs, an SLPP session ID, or both, in the first SLPP message.

[0267]

[0291] In some embodiments, the method 2100 further includes sending a third SLPP message to each of the other UEs of the plurality of UEs, the third SLPP message initiating or resuming an SLPP session, for example, as described for step 7 of FIG. 11 .

[0268]

[0292] In some embodiments, the method 2100 further includes including in the third SLPP message at least one of an application level ID for each UE of the plurality of UEs, an SLPP UE ID for each UE of the plurality of UEs, a group encryption key for the plurality of UEs, or some combination thereof.

[0269]

[0293] In some embodiments, the method 2100 further includes transmitting a first SLPP message to at least one UE of the plurality of UEs to terminate the session at the at least one UE, for example, as described with respect to step 14 of FIG. 11 .

[0270]

[0294] In some embodiments, the method 2100 includes transmitting a first SLPP message to each UE other than the UE of a second plurality of UEs, the second plurality of UEs including the UE and at least some of the other UEs of the plurality of UEs, the first SLPP message including a request for each UE to join the modified session; and, when the third plurality of UEs includes at least one UE, transmitting a second SLPP message to each UE of the third plurality of UEs, the third plurality of UEs including UEs not among the plurality of UEs, the second SLPP message including a request for each UE to join the modified session. and receiving a third SLPP message from each UE of the second plurality of UEs indicating whether each UE accepts or rejects the request, when the third plurality of UEs includes at least one UE, receiving a fourth SLPP message from each UE of the third plurality of UEs indicating whether each UE accepts or rejects the request, and transmitting a fifth SLPP message to each UE except UEs that are not among the second plurality of UEs of the plurality of UEs indicating that the session is terminated at each UE, e.g., as described with respect to Figure 15. In these embodiments, method 2100 may further include transmitting a sixth SLPP message to each UE of the second and third plurality of UEs when each UE accepts the request for each UE to join the modified session, the sixth SLPP message initiating the modified session, e.g., as described with respect to Figure 15. In some of these embodiments, the third plurality of UEs may not include a UE.

[0271]

[0295] In some embodiments, the method 2100 further includes receiving a first SLPP message from a second UE of the plurality of UEs, the first SLPP message including a request for the UE to join, terminate, start, modify, or leave a session, or for the second UE to join a session, and when the first SLPP message includes a request for the UE to join or modify the session or a request for the second UE to join a session, sending to the second UE a second SLPP message indicating acceptance or rejection of the request, for example, as described for steps 4, 5, 7, and 8 of FIG. 11, steps 1 and 2 of FIG. 15, steps 3 and 4 of FIG. 16, steps 1 and 2 of FIG. 17, and steps 1 and 2 of FIG. 18.

[0272]

[0296] In some embodiments, each SLPP message of the plurality of SLPP messages includes at least one of an SLPP session ID, an SLPP transaction ID, a level 2 address of the UE sending the SLPP message, a level 2 address of the UE or group of UEs receiving the SLPP message, information about one or more UEs of the plurality of UEs, the information including an SLPP UE ID for each UE of the one or more UEs of the plurality of UEs, or some combination thereof, for example, as described with respect to steps 7 and 8 of Figures 4A and 4B and Figure 11.

[0273]

[0297] In some embodiments, sidelink positioning of the UEs is performed using at least one of sidelink positioning reference signal (SL PRS) transmission and measurement, real-time kinematics (RTK), WiFi signal transmission and measurement, ultra-wideband (UWB) signal transmission and measurement, or any combination thereof, e.g., as described above following the description of FIG. 19 .

[0274]

[0298] In some embodiments, the sidelink positioning of the plurality of UEs is performed using RTK, wherein each UE of the plurality of UEs acquires carrier phase measurements of Global Navigation Satellite (GNSS) signals, the carrier phase measurements acquired by the plurality of UEs are provided to at least one UE of the plurality of UEs, and the at least one UE determines a location result for the plurality of UEs based on the carrier phase measurements acquired by the plurality of UEs.

[0275]

[0299] In some embodiments, the sidelink positioning of the plurality of UEs is performed using SL PRS transmissions and measurements, and method 2100 may then further include: (i) obtaining an SL PRS transmission configuration for each UE of the plurality of UEs; (ii) obtaining SL PRS measurements for other UEs of the plurality of UEs based on the SL PRS transmission configurations for the other UEs; (iii) transmitting an SL PRS based on the SL PRS transmission configuration for the UE; and (iv) performing at least one of transmitting the obtained SL PRS measurements to at least one other UE of the plurality of UEs or receiving the obtained SL PRS measurements from the at least one other UE of the plurality of UEs, or both, where the obtained SL PRS measurements enable determination of a location result for the target UE, e.g., as described with respect to FIGS. 7 and 11 . The SL PRS measurements may include at least one of receive time-transmit time difference (Rx-Tx), reference signal time difference (RSTD), round trip signal propagation time (RTT), reference signal received power, reference signal received quality, angle of arrival, or any combination thereof.

[0276]

[0300] 22 is a flow diagram of a method 2200 performed by a UE of a plurality of UEs (e.g., UE 105) for supporting sidelink positioning of the plurality of UEs, according to one embodiment. Exemplary components of the UE are provided below with respect to FIGS. 23 and 24.

[0277]

[0301] In block 2210, the function includes determining to perform sidelink positioning of a plurality of UEs, where there is no discovery between the UE and at least some of the other UEs of the plurality of UEs, e.g., as described with respect to FIG. 19(a).

[0278]

[0302] The means for performing the functions of block 2210 may include a bus 2305, a processor 2310, a DSP 2320, a wireless communication interface 2330, a memory 2360, a GNSS receiver 2380, and / or other components of the UE, as illustrated in FIG. 23.

[0279]

[0303] In block 2220, the function includes exchanging, using broadcast or groupcast, a plurality of SLPP messages with other UEs of the plurality of UEs, where the SLPP messages are not part of a session, and the SLPP messages enable sidelink positioning, e.g., as described with respect to FIG. 19.

[0280]

[0304] The means for performing the functions of block 2220 may include a bus 2305, a processor 2310, a DSP 2320, a wireless communication interface 2330, a memory 2360, a GNSS receiver 2380, and / or other components of the UE, as illustrated in FIG. 23.

[0281]

[0305] In some embodiments, performing sidelink positioning includes obtaining location results for at least two target UEs of the plurality of UEs, the location results including at least one of: a range between each target UE and another UE of the plurality of UEs; a direction to or from each target UE to or from another UE of the plurality of UEs, respectively; a location of each target UE relative to a location of another UE of the plurality of UEs; a velocity of each target UE relative to a velocity of another UE of the plurality of UEs; an absolute location of each target UE; an absolute velocity of each target UE; or some combination thereof, e.g., as described for step 4 of FIG. 19 .

[0282]

[0306] In some embodiments, the multiple SLPP messages include at least one SLPP message transmitted by the transmitting UE to another UE among the multiple UEs, where the UE is either the transmitting UE or one of the other UEs, and the at least one SLPP message includes SLPP assistance data for assisting the other UE in transmitting or measuring positioning-related signals, a portion of measurement results or location results obtained by the transmitting UE, or both, a level 2 address of the transmitting UE, an application level address of the transmitting UE, or some combination of these, for example, as described with respect to FIG. 19.

[0283]

[0307] In some embodiments, sidelink positioning of the UEs is performed using at least one of sidelink positioning reference signal (SL PRS) transmission and measurement, real-time kinematics (RTK), WiFi signal transmission and measurement, ultra-wideband (UBW) signal transmission and measurement, or any combination thereof, e.g., as described above following the description of FIG. 19.

[0284]

[0308] In some embodiments, the sidelink positioning of the plurality of UEs is performed using RTK, wherein each UE of the plurality of UEs acquires carrier phase measurements of Global Navigation Satellite (GNSS) signals, the carrier phase measurements acquired by the plurality of UEs are provided to at least one UE of the plurality of UEs, and the at least one UE of the plurality of UEs determines location results for some of the target UEs of the plurality of UEs based on the carrier phase measurements acquired by the plurality of UEs.

[0285]

[0309] In some embodiments, sidelink positioning of the plurality of UEs is performed using transmission and measurement of an SL PRS, and method 2200 then includes receiving an SL PRS transmission configuration from another UE of the plurality of UEs; obtaining SL PRS measurements for the other UE of the plurality of UEs based on the SL PRS transmission configuration; receiving a modified SL PRS transmission configuration from the other UE of the plurality of UEs, the modified SL PRS transmission configuration corresponding to the SL PRS transmitted by the other UE; transmitting the obtained SL PRS measurements for the other UE to the other UE of the plurality of UEs; transmitting an SL PRS based on the SL PRS transmission configuration for the UE; transmitting the SL PRS transmission configuration for the UE to the other UE of the plurality of UEs prior to transmitting the SL PRS; after transmitting the SL PRS, transmitting the modified SL PRS transmission configuration for the UE to the other UE of the plurality of UEs, the modified SL PRS transmission configuration for the UE corresponding to the transmitted SL PRS; receiving PRS measurements and determining location results for some of the target UEs based on at least one of the obtained SL PRS measurements for other UEs, the modified SL PRS transmission configuration for other UEs of the plurality of UEs, the SL PRS measurements obtained by other UEs of the plurality of UEs, and the modified SL PRS transmission configuration for the UE, e.g., as described with respect to Figure 19. In some embodiments, the SL PRS measurements include at least one of a receive time-transmit time difference (Rx-Tx), a reference signal time difference (RSTD), a round-trip signal propagation time (RTT), a reference signal received power, a reference signal received quality, an angle of arrival, or some combination thereof.

[0286]

[0310] 23 is a block diagram of one embodiment of a UE 2300 that may be utilized as described above in this specification (e.g., in connection with the UE 105, receiving device / UE, target UE, cooperating UE, etc., in connection with the preceding figures). It should be noted that FIG. 23 is intended only to provide a generalized illustration of various components, any or all of which may be utilized as desired. Furthermore, the functionality of any UE (e.g., UE 105) described herein may be performed by one or more of the hardware and / or software components illustrated in FIG. 23.

[0287]

[0311] 23. UE 2300 is shown comprising hardware elements that may be electrically coupled (or may otherwise communicate, as needed) via a bus 2305. The hardware elements may include a processor 2310, which may include, but is not limited to, one or more general-purpose processors (e.g., application processors), one or more special-purpose processors (such as digital signal processor (DSP) chips, graphics acceleration processors, application-specific integrated circuits (ASICs)), and / or other processing structures or means. The processor 2310 may include one or more processing units that may be housed in a single integrated circuit (IC) or multiple ICs. As shown in FIG. 23, some embodiments may have a separate DSP 2320 depending on desired functionality. Location determination and / or other decisions based on wireless communication may be performed in the processor 2310 and / or in a wireless communication interface 2330 (described below). The UE 2300 may also include one or more input devices 2370, which may include, but are not limited to, one or more keyboards, touchscreens, touchpads, microphones, buttons, dials, switches, etc., and one or more output devices 2315, which may include, but are not limited to, one or more displays (e.g., touchscreens), light emitting diodes (LEDs), speakers, etc.

[0288]

[0312] The UE 2300 may also include a wireless communication interface 2330, which may comprise, but is not limited to, a modem, a network card, an infrared communication device, a wireless communication device, and / or a chipset (such as a Bluetooth device, an IEEE 802.11 device, an IEEE 802.15.4 device, a Wi-Fi device, a WiMAX device, a WAN device, and / or various cellular devices), which may enable the UE 2300 to communicate with other devices as described in the above embodiments. The wireless communication interface 2330 may enable data and signaling to be communicated (e.g., transmitted and received) with a TRP of a network, as described herein, for example, via an eNB, a gNB, an ng-eNB, an access point, various base stations and / or other access node types, and / or other network components, computer systems, and / or any other electronic devices communicatively coupled to the TRP. Communication may be performed via one or more wireless communication antennas 2332 that transmit and / or receive wireless signals 2334. According to some embodiments, the wireless communication antenna 2332 may include multiple individual antennas, an antenna array, or any combination thereof. The antenna 2332 may be capable of transmitting and receiving wireless signals using beams (e.g., Tx beams and Rx beams). Beamforming may be performed using digital and / or analog beamforming techniques using respective digital and / or analog circuitry. The wireless communication interface 2330 may include such circuitry.

[0289]

[0313] Depending on desired functionality, the wireless communication interface 2330 may include separate receivers and transmitters, or any combination of transceivers, transmitters, and / or receivers, for communicating with base stations (e.g., ng-eNBs and gNBs) and other terrestrial transceivers, such as wireless devices and access points. The UE 2300 may communicate with different data networks, which may comprise a variety of network types. For example, one such network type may include a wireless wide area network (WWAN), which may be a code division multiple access (CDMA) network, a time division multiple access (TDMA) network, a frequency division multiple access (FDMA) network, an orthogonal frequency division multiple access (OFDMA) network, a single-carrier frequency division multiple access (SC-FDMA) network, a WiMAX (IEEE 802.16) network, etc. A CDMA network may implement one or more radio access technologies (RATs), such as CDMA2000, wideband code division multiple access (WCDMA), etc. CDMA2000® includes the IS-95 standard, the IS-2000 standard, and / or the IS-856 standard. A TDMA network may implement Global System for Mobile Communications (GSM), Digital Advanced Mobile Phone System (D-AMPS), or some other RAT. An OFDMA network may employ Long Term Evolution (LTE), LTE Advanced, Fifth Generation (5G) New Radio (NR), etc. 5G NR, LTE, LTE Advanced, GSM, and WCDMA are described in documents from the 3rd Generation Partnership Project (3GPP). CDMA2000® is described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). 3GPP and 3GPP2 documents are publicly available.A wireless local area network (WLAN) may also be an IEEE 802.11x network, and a wireless personal area network (WPAN) may be a Bluetooth network, an IEEE 802.15x, or some other type of network. The techniques described herein may also be used for any combination of WWAN, WLAN, and / or WPAN.

[0290]

[0314] The UE 2300 may further include sensors 2340. The sensors 2340 may include, but are not limited to, one or more inertial sensors and / or other sensors (e.g., accelerometers, gyroscopes, cameras, magnetometers, altimeters, microphones, proximity sensors, light sensors, barometers, etc.), some of which may be used to obtain location-related measurements and / or other information.

[0291]

[0315] Embodiments of UE 2300 may also include a Global Navigation Satellite System (GNSS) receiver 2380 capable of receiving signals 2384 from one or more GNSS satellites using antenna 2382 (which may be the same as antenna 2332). Positioning based on GNSS signal measurements may be utilized to complement and / or incorporate the techniques described herein. GNSS receiver 2380 may use conventional techniques to extract a location of device 2300 from GNSS satellites of GNSS systems such as Global Positioning System (GPS), Galileo, GLONASS, Quasi-Zenith Satellite System (QZSS) over Japan, IRNSS over India, and Beidou Navigation Satellite System (BDS) over China. Furthermore, the GNSS receiver 2380 can be used with various augmentation systems (e.g., Satellite Based Augmentation System (SBAS)) associated with or adapted for use with one or more global and / or regional navigation satellite systems, such as, for example, the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay Service (EGNOS), the Multi-functional Satellite Augmentation System (MSAS), and the Geo Augmented Navigation system (GAGAN).

[0292]

[0316] It should be noted that while the GNSS receiver 2380 is illustrated in FIG. 23 as a separate component, embodiments are not limited to this. As used herein, the term “GNSS receiver” may include hardware and / or software components configured to acquire GNSS measurements (measurements from GNSS satellites). Thus, in some embodiments, the GNSS receiver may comprise a measurement engine executed (as software) by one or more processors, such as the processor 2310, the DSP 2320, and / or a processor in the wireless communication interface 2330 (e.g., in a modem). The GNSS receiver may also optionally include a positioning engine, which can use the GNSS measurements from the measurement engine to determine the position of the GNSS receiver using an Extended Kalman Filter (EKF), Weighted Least Squares (WLS), a Hatch filter, a particle filter, etc. The positioning engine may also be executed by one or more processors, such as the processor 2310 or the DSP 2320.

[0293]

[0317] The UE 2300 may further include and / or be in communication with memory 2360. The memory 2360 may include, but is not limited to, local and / or network-accessible storage devices, disk drives, drive arrays, optical storage devices, solid-state storage devices such as random access memory (RAM) and / or read-only memory (ROM), which may be programmable, flash-updateable, etc. Such storage devices may be configured to implement any suitable data store, including, but not limited to, various file systems, database structures, etc.

[0294]

[0318] The memory 2360 of the UE 2300 may also comprise software elements (not shown in FIG. 23 ) including other code, such as an operating system, device drivers, executable libraries, and / or one or more application programs, which may include computer programs provided by various embodiments as described herein and / or may be designed to implement methods and / or configure systems provided by other embodiments. By way of example only, one or more procedures described with respect to the methods discussed above may be implemented as code and / or instructions in the memory 2360 executable by the UE 2300 (and / or the processor 2310 or DSP 2320 within the UE 2300). In some embodiments, such code and / or instructions may then be used to configure and / or adapt a general-purpose computer (or other device) to perform one or more operations in accordance with the described methods.

[0295]

[0319] Figure 24 shows a schematic block diagram illustrating certain exemplary features of a UE 2400, which may be, for example, the UE 105 shown in Figures 1, 3, 5-9, and 11-19, and any of the UEs shown in Figures 2 and 10, supporting sidelink positioning of the UE 2400. The UE 2400 may perform, for example, signal flows 1100-1900 shown in Figures 11-19, respectively, and methods 2000-2200 shown in Figures 20-22, respectively, and accompanying techniques as described herein. The UE 2400 may include, for example, one or more processors 2402, memory 2404, an external interface such as at least one wireless transceiver (e.g., wireless network interface) shown as a Wireless Wide Area Network (WWAN) transceiver 2410, a Wireless Local Area Network (WLAN) transceiver 2411, an Ultra Wide Band (UWB) transceiver 2412, and a Bluetooth (BT) transceiver 2413, an SPS receiver 2414, and one or more sensors 2415, which may be operatively coupled to the non-transitory computer-readable medium 2420 and the memory 2404 using one or more connections 2406 (e.g., a bus, wires, fiber, link, etc.). The SPS receiver 2414 may receive and process SPS signals, for example, from the satellite vehicle 190 shown in FIG. 1. The one or more sensors 2415 may be, for example, an Inertial Measurement Unit (IMU), which may include one or more accelerometers, one or more gyroscopes, magnetometers, etc. The UE 2400 may further include additional items not shown, such as a user interface through which a user may interface with the UE 2400, which may include a display, a keypad, or other input devices such as a virtual keypad on a display. In certain example implementations, all or a portion of the UE 2400 may be in the form of a chipset or the like.

[0296]

[0320] The UE 2400 may include at least one wireless transceiver, such as a wireless transceiver 2410 for a WWAN communication system and a wireless transceiver 2411 for a WLAN communication system, a UWB transceiver 2412 for a UWB communication system, a BT transceiver 2413 for a Bluetooth communication system, or a combined transceiver for any of WWAN, WLAN, UWB, and BT. The WWAN transceiver 2410 may include a transmitter 2410t and a receiver 2410r coupled to one or more antennas 2409 to transmit (e.g., on one or more uplink channels and / or one or more sidelink channels) and / or receive (e.g., on one or more downlink channels and / or one or more sidelink channels) wireless signals and convert signals from wireless to wired (e.g., electrical and / or optical) signals and from wired (e.g., electrical and / or optical) signals to wireless signals. The WLAN transceiver 2411 may include a transmitter 2411t and a receiver 2411r coupled to one or more antennas 2409 or separate antennas to transmit (e.g., on one or more uplink channels and / or one or more sidelink channels) and / or receive (e.g., on one or more downlink channels and / or one or more sidelink channels) wireless signals and convert signals from wireless to wired (e.g., electrical and / or optical) signals and from wired (e.g., electrical and / or optical) signals to wireless signals. The UWB transceiver 2412 may include a transmitter 2412t and a receiver 2412r coupled to one or more antennas 2409 or separate antennas to transmit (e.g., on one or more uplink channels and / or one or more sidelink channels) and / or receive (e.g., on one or more downlink channels and / or one or more sidelink channels) wireless signals and convert signals from wireless to wired (e.g., electrical and / or optical) signals and from wired (e.g., electrical and / or optical) signals to wireless signals.The BT transceiver 2413 may include a transmitter 2413t and a receiver 2413r coupled to one or more antennas 2409 or separate antennas to transmit (e.g., on one or more uplink channels and / or one or more sidelink channels) and / or receive (e.g., on one or more downlink channels and / or one or more sidelink channels) wireless signals and convert signals from wireless to wired (e.g., electrical and / or optical) signals and from wired (e.g., electrical and / or optical) signals to wireless signals. The transmitters 2410t, 2411t, 2412t, and 2413t may include multiple transmitters, which may be separate components or combined / integrated components, and / or the receivers 2410r, 2411r, 2412r, and 2413r may include multiple receivers, which may be separate components or combined / integrated components. The WWAN transceiver 2410 may be configured to communicate signals (e.g., with base stations and / or one or more other UEs or other devices) in accordance with various radio access technologies (RATs), such as New Radio (NR), Global System for Mobiles (GSM), Universal Mobile Telecommunications System (UMTS), Advanced Mobile Phone System (AMPS), Code Division Multiple Access (CDMA), Wideband CDMA (WCDMA), Long-Term Evolution (LTE), LTE Direct (LTE-D), 3GPP LTE-V2X (PC5), etc. New Radio (NR) may use mmWave and / or sub-6 GHz frequencies.The WLAN transceiver 2411 may be configured to communicate signals (e.g., with access points and / or one or more other devices) according to various radio access technologies (RATs), such as 3GPP LTE-V2X (PC5), IEEE 1102.11 (including IEEE 1102.11p), Wi-Fi, Wi-Fi Direct (Wi-Fi D), Zigbee, etc. The UWB transceiver 2412 may be configured to communicate signals (e.g., with access points and / or one or more other devices) according to various radio access technologies (RATs), such as a personal area network (PAN), including IEEE 802.15.3, IEEE 802.15.4, etc. The BT transceiver 2413 may be configured to communicate signals (e.g., with access points and / or one or more other devices) according to various radio access technologies (RATs), such as a Bluetooth network. The transceivers 2410, 2411, 2412, and 2413 may be communicatively coupled, for example, by optical and / or electrical connections, to a transceiver interface that may be at least partially integrated with the transceivers 2410, 2411, 2412, and 2413.

[0297]

[0321] In some embodiments, the UE 2400 may include an antenna 2409, which may be internal or external. The UE antenna 2409 may be used to transmit and / or receive signals that are processed by the wireless transceivers 2410, 2411, 2412, and 2413. In some embodiments, the UE antenna 2409 may be coupled to the wireless transceivers 2410, 2411, 2412, and 2413. In some embodiments, measurements of signals received (transmitted) by the UE 2400 may be performed at the connection point between the UE antenna 2409 and the wireless transceivers 2410, 2411, 2412, and 2413. For example, the measurement reference points for the received (transmitted) RF signals may be the input (output) of the receiver 2410r (transmitter 2410t) and the output (input) of the UE antenna 2409. In a UE 2400 with multiple UE antennas 2409 or antenna arrays, the antenna connectors may be viewed as being virtual points representing the aggregate outputs (inputs) of the multiple UE antennas.

[0298]

[0322] The one or more processors 2402 may be implemented using a combination of hardware, firmware, and software. For example, the one or more processors 2402 may be configured to perform the functions described herein by implementing one or more instructions or program code 2408 on a non-transitory computer-readable medium, such as the medium 2420 and / or the memory 2404. In some embodiments, the one or more processors 2402 may represent one or more circuits configurable to perform at least a portion of a data signal computation procedure or process associated with the operation of the UE 2400.

[0299]

[0323] The medium 2420 and / or memory 2404 may store instructions or program code 2408, including executable code or software instructions that, when executed by the one or more processors 2402, cause the one or more processors 2402 to operate as special-purpose computers programmed to perform the techniques disclosed herein. As shown in the UE 2400, the medium 2420 and / or memory 2404 may include one or more components or modules that may be implemented by the one or more processors 2402 to perform the methods described herein. While a component or module is shown as software in the medium 2420 executable by the one or more processors 2402, it should be understood that the component or module may be stored in the memory 2404 or may be dedicated hardware residing either within or external to the one or more processors 2402.

[0300]

[0324] A number of software modules and data tables may reside in the medium 2420 and / or memory 2404 and be utilized by the one or more processors 2402 to manage both the communications and functionality described herein. It should be understood that the organization of the contents of the medium 2420 and / or memory 2404 as shown in the UE 2400 is merely exemplary, and thus the functionality of the modules and / or data structures may be combined, separated, and / or structured in different ways depending on the implementation of the UE 2400.

[0301]

[0325] The medium 2420 and / or memory 2404 may include an SLPP message module 2422 that, when implemented by the one or more processors 2402, configures the one or more processors 2402 to send and receive sidelink positioning (e.g., SLPP) messages via an external interface, including one or more of the wireless transceivers 2410, 2411, 2412, and 2413. The sidelink positioning messages may use SLPP as described herein. The one or more processors 2402 may be configured to send SLPP messages directly to one or more other UEs via the external interface or to broadcast the SLPP messages to multiple other UEs using groupcast or multicast. The one or more processors 2402 may be configured to transmit and receive SLPP messages to and from a location server (e.g., LMF) in the PLMN using SLPP messages embedded in LPP messages, embedded in both LPP messages and SUPL messages (e.g., which may include SUPL POS messages), embedded only in SUPL messages (e.g., which may include SUPL POS messages), or not embedded in LPP or SUPL messages via the external interface. The one or more processors 2402 may be configured to transmit and receive SLPP messages including, for example, an SLPP capability request or SLPP capabilities, SLPP resources, and / or SLPP service requirements for the UE via the external interface. The one or more processors 2402 may be configured to transmit and receive, for example, a proposed PRS configuration for sidelink positioning via the external interface, and may be configured to transmit and receive, for example, a confirmation, rejection, or modification of a proposed PRS configuration for sidelink positioning via the external interface. Sidelink positioning messages may use SLPP as described herein. The one or more processors 2402 may be configured to send and receive SLPP messages including measurement reports or location results, for example, via an external interface.The transmitted measurement report may include, for example, information about sidelink positioning signals transmitted by the UE and measurements performed by the UE 2400 on sidelink positioning signals transmitted by other UEs, and may include an indication of reverse link communications from each UE in the group to the UE 2400. The received measurement report may include, for example, measurements performed by other UEs, including measurements on sidelink positioning signals transmitted by the UE 2400, and may include an indication of reverse link communications from each UE in the group to each of the other UEs in the group. The location results may include range, distance, and / or direction between one or more pairs of UEs in the group, and / or relative locations, absolute locations, and / or velocities and / or relative speeds for each of one or more UEs in the group.

[0302]

[0326] The medium 2420 and / or memory 2404 may include a PRS module 2423 that, when implemented by the one or more processors 2402, configures the one or more processors 2402 to transmit a PRS for sidelink positioning (e.g., a sidelink PRS or a sidelink SRS for NR or LTE) via an external interface including one or more of the wireless transceivers 2410, 2411, 2412, and 2413. The one or more processors 2402 may be configured to transmit an SL PRS that matches a proposed SL PRS configuration transmitted to or received from another UE. The one or more processors 2402 may be further configured to receive an SL PRS from another UE via the external interface and measure the SL PRS for sidelink positioning.

[0303]

[0327] The medium 2420 and / or memory 2404 may include a location module 2424 that, when implemented by the one or more processors 2402, configures the one or more processors 2402 to determine a location result for one or more UEs relative to the UE 2400 based on SL PRS measurements performed by the UE 2400 and measurement information received in SLPP messages from other UEs. The one or more processors 2402 may be further configured to determine a velocity of the UE 2400 and / or other UEs based on the SL PRS measurements performed by the UE 2400 and measurement information received in SLPP messages from the other UEs.

[0304]

[0328] The medium 2420 and / or the memory 2404 may include a discovery module 2426 that, when implemented by the one or more processors 2402, configures the one or more processors 2402 to discover one or more other UEs available for sidelink positioning. The one or more processors 2402 may be further configured to obtain group criteria parameters for the other UEs, such as a distance restriction, a time restriction, a movement direction restriction, a speed restriction, a sidelink positioning method restriction, or a sidelink positioning method type restriction.

[0305]

[0329] The medium 2420 and / or memory 2404 may include a group management module 2428 that, when implemented by the one or more processors 2402, configures the one or more processors 2402 to determine a group status indication for one or more UEs indicating the inclusion or exclusion of the UE in the group based on group criteria parameters. The one or more processors 2402 may be further configured to determine a group status indication for one or more UEs in the group indicating the inclusion or exclusion of the UE in the group based on an indication of reverse link communication for the one or more UEs, including an indication of reverse link communication from each UE and an indication of reverse link communication from the UE 2400. The one or more processors 2402 may be further configured to cause the addition or transfer of one or more UEs from one group to another based on the relative locations and velocities of the one or more UEs and UEs in the group.

[0306]

[0330] The methods described herein may be implemented by various means, depending on the application. For example, the methods may be implemented in hardware, firmware, software, or any combination thereof. In a hardware implementation, the one or more processors 2402 may be implemented with one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, electronic devices, other electronic units designed to perform the functions described herein, or combinations thereof.

[0307]

[0331] For a firmware and / or software implementation, the methods may be implemented with modules (e.g., procedures, functions, etc.) that perform the functions described herein. Any machine-readable medium tangibly embodying instructions may be used in performing the methods described herein. For example, software code may be stored in non-transitory computer-readable medium 2420 or memory 2404 coupled to and executed by one or more processors 2402. Memory may be implemented within the one or more processors or external to the one or more processors. The term "memory," as used herein, may refer to any type of long-term, short-term, volatile, non-volatile, or other memory, and is not limited to a particular type or number of memories, or to a particular type of medium on which the memory is stored.

[0308]

[0332] If implemented in firmware and / or software, the functions may be stored as one or more instructions or program code 2408 on a non-transitory computer-readable medium, such as medium 2420 and / or memory 2404. Examples include computer-readable media encoded with data structures and computer-readable media encoded with computer program code 2408. For example, non-transitory computer-readable media having program code 2408 stored thereon may include program code 2408 for supporting sidelink positioning in a manner consistent with the disclosed embodiments. Non-transitory computer-readable media 2420 includes physical computer storage media. Storage media may be any available medium that can be accessed by a computer. By way of example, and not limitation, such non-transitory computer-readable media may include 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 store desired program code 2408 in the form of instructions or data structures and that can be accessed by a computer. As used herein, "disk" and "disc" include a compact disc (CD), a laser disc, an optical disc, a digital versatile disc (DVD), a floppy disk, and a Blu-ray disc, although a "disk" typically reproduces data magnetically and a "disc" reproduces data optically using a laser. Combinations of the above are also intended to be included within the scope of computer-readable media.

[0309]

[0333] In addition to being stored on the computer-readable medium 2420, the instructions and / or data may be provided as signals on a transmission medium contained within the communications device. For example, the communications device may include an external interface including one or more of wireless transceivers 2410, 2411, 2412, and 2413 having signals indicative of the instructions and data. The instructions and data are configured to cause one or more processors to perform the functions outlined in the claims. That is, the communications device includes a transmission medium bearing signals indicative of information to perform the disclosed functions.

[0310]

[0334] Memory 2404 may represent any data storage mechanism. Memory 2404 may include, for example, primary memory and / or secondary memory. Primary memory may include, for example, random access memory, read-only memory, etc. While shown in this example as being separate from one or more processors 2402, it should be understood that all or a portion of the primary memory may be provided within one or more processors 2402 or may otherwise be co-located / coupled with one or more processors 2402. Secondary memory may include, for example, the same or similar type of memory as the primary memory and / or one or more data storage devices or systems, such as, for example, disk drives, optical disk drives, tape drives, solid-state memory drives, etc.

[0311]

[0335] In particular implementations, the secondary memory may operably receive or otherwise be configurable to couple to a non-transitory computer-readable medium 2420. Thus, in certain example implementations, the methods and / or apparatuses presented herein may take the form, in whole or in part, of a computer-readable medium 2420 having stored thereon computer-implementable program code 2408 which, when executed by one or more processors 2402, may be operably enabled to perform all or a portion of the example operations as described herein. The computer-readable medium 2420 may be part of the memory 2404.

[0312]

[0336] It will be apparent to those skilled in the art that substantial variations may be made according to particular requirements. For example, customized hardware might also be used and / or particular elements might be implemented in hardware, software (including portable software such as applets), or both. Furthermore, connection to other computing devices, such as network input / output devices, might be utilized.

[0313]

[0337] With reference to the accompanying figures, components that may include memory may also include non-transitory machine-readable media. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any storage medium that participates in providing data that causes a machine to operate in a specific manner. In the embodiments provided above, various machine-readable media may participate in providing instructions / code to a processor and / or other device(s) for execution. Additionally or alternatively, machine-readable media may be used to store and / or transport such instructions / code. In many implementations, computer-readable media are physical and / or tangible storage media. Such media may take many forms, including, but not limited to, non-volatile media and volatile media. Common forms of computer-readable media include, for example, magnetic and / or optical media, any other physical media with a pattern of holes, RAM, programmable ROM (PROM), erasable PROM (EPROM), FLASH-EPROM, any other memory chip or cartridge, or any other medium from which a computer can read instructions and / or code.

[0314]

[0338] The methods, systems, and devices described herein are examples. Various embodiments may omit, substitute, or add various procedures or components, as appropriate. For example, features described with respect to some embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be similarly combined. Various components of the diagrams provided herein may be embodied in hardware and / or software. Also, technology evolves, and therefore, many of the elements are examples that do not limit the scope of the disclosure to those specific examples.

[0315]

[0339] It has proven convenient at times, principally for reasons of common usage, to refer to such signals as bits, information, values, elements, symbols, characters, variables, terms, numbers, numerical values, or the like. It should be understood, however, that all of these or similar terms are merely convenient labels and are to be associated with the appropriate physical quantities. Unless otherwise expressly stated, and as is clear from the above description, throughout this specification, descriptions utilizing terms such as "processing," "calculating," "calculating," "determining," "ascertaining," "identifying," "associating," "measuring," "performing," and the like, should be understood to refer to actions or processes of a particular apparatus, such as a special purpose computer or similar special purpose electronic computing device. Thus, in the context of this specification, a special purpose computer or similar special purpose electronic computing device is capable of manipulating or transforming signals that are typically represented as physical electronic, electrical, or magnetic quantities within the memories, registers, or other information storage, transmission, or display devices of the special purpose computer or similar special purpose electronic computing device.

[0316]

[0340] The terms "and" and "or" as used herein may include a variety of meanings that are expected to depend, at least in part, on the context in which such terms are used. Generally, when "or" is used to associate a list, such as A, B, or C, it is intended to mean A, B, and C, which are used herein in an inclusive sense, as well as A, B, or C, which are used herein in an exclusive sense. Additionally, as used herein, the term "one or more" may be used to refer to any feature, structure, or characteristic in the singular, or may be used to refer to any combination of features, structures, or characteristics. However, it should be noted that this is merely an illustrative example, and claimed subject matter is not limited to this example. Furthermore, the term "at least one of," when used to associate a list, such as A, B, or C, may be interpreted to mean any combination of A, B, and / or C, such as A, AB, AA, AAB, AABBCCC, etc.

[0317]

[0341] While several embodiments have been described, various modifications, alternative configurations, and equivalents may be used without departing from the scope of the present disclosure. For example, the above elements may merely be components of a larger system in which other rules may take precedence over or otherwise modify the application of the various embodiments. Also, some steps may be taken before, during, or after the above elements are considered. Therefore, the above description does not limit the scope of the present disclosure.

[0318] Clause 1. An exemplary method performed by a user equipment (UE) for sidelink positioning of a plurality of UEs including the UE, the method including: determining a session for a Sidelink Positioning Protocol (SLPP) for the plurality of UEs, the session indicated to each UE of the plurality of UEs; and exchanging a plurality of SLPP messages with other UEs of the plurality of UEs, the SLPP messages being part of the session, the SLPP messages enabling sidelink positioning.

[0319] Clause 2. The method of clause 1, wherein performing sidelink positioning includes obtaining location results for at least two target UEs of the plurality of UEs, the location results including at least one of a range between each target UE and another UE of the plurality of UEs, a direction to or from each target UE, respectively, to or from another UE of the plurality of UEs, a location of each target UE relative to a location of another UE of the plurality of UEs, a velocity of each target UE relative to a velocity of another UE of the plurality of UEs, an absolute location of each target UE, an absolute velocity of each target UE, or any combination thereof.

[0320] Clause 3. The method of clause 1 or 2, wherein the plurality of SLPP messages includes at least one SLPP message sent by the transmitting UE to the receiving UE or receiving group of UEs, the UE being either the transmitting UE, the receiving UE, or part of the receiving group of UEs, and the at least one SLPP message includes SLPP capabilities of the transmitting UE, a request for SLPP capabilities of the receiving UE or receiving group of UEs, SLPP assistance data to assist the receiving UE or receiving group of UEs in transmitting or measuring positioning-related signals, a request for SLPP assistance data from the receiving UE to assist the transmitting UE in transmitting or measuring positioning-related signals, a request for some or both of measurements or location results obtained by the receiving UE or receiving group of UEs, some or both of measurement results or location results obtained by the transmitting UE, or any combination thereof.

[0321] Clause 4. The method of any one of clauses 1 to 3, further comprising: discovering each other UE of the plurality of UEs; receiving an indication from each other UE of the plurality of UEs that each other UE supports SLPP; and determining to initiate a session based on a service request received from a network entity or a configuration of the UE.

[0322] Clause 5. The method of any one of clauses 1 to 4, further comprising each UE sending a first SLPP message to each of the other UEs of the plurality of UEs including a request to join the session, and receiving a second SLPP message from each of the other UEs of the plurality of UEs indicating acceptance or rejection of the request.

[0323] Clause 6. The method of any one of clauses 1 to 5, further comprising including in the first SLPP message at least one of a level 2 group address of the plurality of UEs, an SLPP session ID, or both.

[0324] Clause 7. A method according to any one of clauses 1 to 6, further comprising sending a third SLPP message to each of the other UEs of the plurality of UEs, the third SLPP message initiating or resuming an SLPP session.

[0325] Clause 8. The method of any one of clauses 1 to 7, further comprising including in the third SLPP message at least one of an application level ID for each UE of the plurality of UEs, an SLPP UE ID for each UE of the plurality of UEs, a group encryption key for the plurality of UEs, or any combination thereof.

[0326] Clause 9. The method of any one of clauses 1 to 8, further comprising sending a first SLPP message to at least one UE of the plurality of UEs to terminate the session at the at least one UE.

[0327] Clause 10. Sending a first SLPP message to each UE other than the UE of a second plurality of UEs, the second plurality of UEs including the UE and at least some of the other UEs of the plurality of UEs, the first SLPP message including a request for each UE to join the modified session; and when a third plurality of UEs includes at least one UE, sending a second SLPP message to each UE of the third plurality of UEs, the third plurality of UEs including UEs not among the plurality of UEs, the second SLPP message including a request for each UE to join the modified session. receiving a third SLPP message from each UE of the second plurality of UEs indicating whether each UE accepts or rejects the request; when the third plurality of UEs includes at least one UE, receiving a fourth SLPP message from each UE of the third plurality of UEs indicating whether each UE accepts or rejects the request; and sending a fifth SLPP message to each UE, except for UEs that are not among the second plurality of UEs of the plurality of UEs, indicating that the session is terminated at each UE.

[0328] Clause 11. The method of any one of clauses 1 to 10, further comprising sending a sixth SLPP message to each UE of the second plurality of UEs and the third plurality of UEs when each UE accepts a request for each UE to join the modified session, the sixth SLPP message initiating the modified session.

[0329] Clause 12. The method of any one of clauses 1 to 11, wherein the third plurality of UEs does not include any UE.

[0330] Clause 13. The method of any one of clauses 1 to 12, further comprising: receiving a first SLPP message from a second UE of the plurality of UEs, the first SLPP message including a request for the UE to join, terminate, start, modify, or leave a session, or a request for the second UE to join a session; and, when the first SLPP message includes a request for the UE to join or modify a session, or a request for the second UE to join a session, sending a second SLPP message to the second UE, the second SLPP message indicating acceptance or rejection of the request.

[0331] Clause 14. A method according to any one of clauses 1 to 13, wherein each SLPP message of the plurality of SLPP messages includes at least one of an SLPP session ID, an SLPP transaction ID, a level 2 address of a UE sending the SLPP message, a level 2 address of a UE or group of UEs receiving the SLPP message, information about one or more UEs of the plurality of UEs, the information including an SLPP UE ID for each UE of the one or more UEs of the plurality of UEs, or any combination thereof.

[0332] Clause 15. The method of any one of clauses 1 to 14, wherein the sidelink positioning of the plurality of UEs is performed using at least one of transmitting and measuring sidelink positioning reference signals (SL PRS), real-time kinematics (RTK), transmitting and measuring WiFi signals, transmitting and measuring ultra-wideband (UWB) signals, or any combination thereof.

[0333] Clause 16. The method of any one of clauses 1 to 15, wherein sidelink positioning of the plurality of UEs is performed using RTK, each UE of the plurality of UEs acquires carrier phase measurements of Global Navigation Satellite (GNSS) signals, the carrier phase measurements acquired by the plurality of UEs are provided to at least one UE of the plurality of UEs, and the at least one UE determines location results for the plurality of UEs based on the carrier phase measurements acquired by the plurality of UEs.

[0334] Clause 17. The method of any one of clauses 1 to 16, wherein sidelink positioning of the plurality of UEs is performed using SL PRS transmissions and measurements, and further comprising: obtaining an SL PRS transmission configuration for each UE of the plurality of UEs; obtaining SL PRS measurements for other UEs of the plurality of UEs based on the SL PRS transmission configurations for the other UEs; transmitting SL PRS based on the SL PRS transmission configuration for the UE; and transmitting the obtained SL PRS measurements to at least one other UE of the plurality of UEs or receiving the obtained SL PRS measurements from at least one other UE of the plurality of UEs, or both, wherein the obtained SL PRS measurements enable determination of a location result for the target UE.

[0335] Clause 18.SL The method of any one of clauses 1 to 17, wherein the PRS measurements include at least one of receive time-transmit time difference (Rx-Tx), reference signal time difference (RSTD), round trip signal propagation time (RTT), reference signal received power, reference signal received quality, angle of arrival, or any combination thereof.

[0336] Clause 19. An exemplary method performed by a user equipment (UE) for sidelink positioning of a plurality of UEs, including the UE, comprising: determining to perform sidelink positioning of the plurality of UEs, where there is no discovery between the UE and at least some of the other UEs of the plurality of UEs; and exchanging, using broadcast or groupcast, a plurality of SLPP messages with the other UEs of the plurality of UEs, where the SLPP messages are not part of a session, and the SLPP messages enable the sidelink positioning.

[0337] Clause 20. The method of clause 19, further comprising obtaining location results for at least two target UEs of the plurality of UEs, the location results including at least one of a range between each target UE and another UE of the plurality of UEs, a direction to or from each target UE, respectively, to or from another UE of the plurality of UEs, a location of each target UE relative to a location of another UE of the plurality of UEs, a velocity of each target UE relative to a velocity of another UE of the plurality of UEs, an absolute location of each target UE, an absolute velocity of each target UE, or any combination thereof.

[0338] Clause 21. A method as described in clause 19 or 20, wherein the plurality of SLPP messages includes at least one SLPP message sent by the transmitting UE to another UE among the plurality of UEs, the UE being either the transmitting UE or one of the other UEs, and the at least one SLPP message includes SLPP assistance data for assisting the other UE in transmitting or measuring positioning-related signals, a portion of a measurement result or a location result obtained by the transmitting UE, or both, a level 2 address of the transmitting UE, an application level address of the transmitting UE, or any combination thereof.

[0339] Clause 22. The method of any one of clauses 19 to 21, wherein the sidelink positioning of the plurality of UEs is performed using at least one of transmitting and measuring sidelink positioning reference signals (SL PRS), real-time kinematics (RTK), transmitting and measuring WiFi signals, transmitting and measuring ultra-wideband (UBW) signals, or any combination thereof.

[0340] Clause 23. The method of any one of clauses 19 to 22, wherein sidelink positioning of the plurality of UEs is performed using RTK, wherein each UE of the plurality of UEs acquires carrier phase measurements of Global Navigation Satellite (GNSS) signals, the carrier phase measurements acquired by the plurality of UEs are provided to at least one UE of the plurality of UEs, and the at least one UE of the plurality of UEs determines location results for some of the target UEs of the plurality of UEs based on the carrier phase measurements acquired by the plurality of UEs.

[0341] Clause 24. Sidelink positioning of a plurality of UEs is performed using transmission and measurement of SL PRS, comprising: receiving an SL PRS transmission configuration from another UE of the plurality of UEs; obtaining SL PRS measurements for another UE of the plurality of UEs based on the SL PRS transmission configuration; receiving a modified SL PRS transmission configuration from another UE of the plurality of UEs, the modified SL PRS transmission configuration corresponding to the SL PRS transmitted by the other UE; transmitting the obtained SL PRS measurements for the other UE to another UE of the plurality of UEs; transmitting an SL PRS based on the SL PRS transmission configuration for the UE; transmitting the SL PRS transmission configuration for the UE to another UE of the plurality of UEs before transmitting the SL PRS; after transmitting the SL PRS, transmitting the modified SL PRS transmission configuration for the UE to another UE of the plurality of UEs, the modified SL PRS transmission configuration for the UE corresponding to the transmitted SL PRS; receiving the obtained SL PRS measurements by the other UE of the plurality of UEs; 24. The method of any one of clauses 19 to 23, further comprising: determining location results for some of the target UEs based on at least one of the PRS measurements, a modified SL PRS transmission configuration for other UEs of the plurality of UEs, SL PRS measurements obtained by other UEs of the plurality of UEs, and the modified SL PRS transmission configuration for the UE.

[0342] Clause 25.SL The method of any one of clauses 18 to 24, wherein the PRS measurements include at least one of receive time-transmit time difference (Rx-Tx), reference signal time difference (RSTD), round trip signal propagation time (RTT), reference signal received power, reference signal received quality, angle of arrival, or any combination thereof.

[0343] An exemplary UE for sidelink positioning of a plurality of UEs, including a UE, comprises a transceiver, a memory, and one or more processors communicatively coupled to the transceiver and the memory. The one or more processors may be configured to: determine a Sidelink Positioning Protocol (SLPP) session for the plurality of UEs, the session indicated to each UE of the plurality of UEs; and exchange a plurality of SLPP messages with other UEs of the plurality of UEs, the SLPP messages being part of the session, the SLPP messages enabling sidelink positioning.

[0344] Clause 27. The UE of Clause 26, wherein the one or more processors are further configured to obtain location results for at least two target UEs of the plurality of UEs, the location results including at least one of a range between each target UE and another UE of the plurality of UEs, a direction to or from each target UE, respectively, to or from another UE of the plurality of UEs, a location of each target UE relative to a location of another UE of the plurality of UEs, a velocity of each target UE relative to a velocity of another UE of the plurality of UEs, an absolute location of each target UE, an absolute velocity of each target UE, or any combination thereof.

[0345] Clause 28. A UE as described in Clause 26 or 27, wherein the plurality of SLPP messages includes at least one SLPP message sent by a transmitting UE to a receiving UE or receiving group of UEs, the UE being either a transmitting UE, a receiving UE, or part of a receiving group of UEs, and the at least one SLPP message includes SLPP capabilities of the transmitting UE, a request for SLPP capabilities of the receiving UE or receiving group of UEs, SLPP assistance data to assist the receiving UE or receiving group of UEs in transmitting or measuring positioning-related signals, a request for SLPP assistance data from the receiving UE to assist the transmitting UE in transmitting or measuring positioning-related signals, a request for some or both of measurements or location results obtained by the receiving UE or receiving group of UEs, some or both of measurement results or location results obtained by the transmitting UE, or any combination thereof.

[0346] Clause 29. The UE of any one of clauses 26 to 28, wherein the one or more processors are further configured to: discover each other UE of the plurality of UEs; receive an indication from each other UE of the plurality of UEs that each other UE supports SLPP; and determine to initiate a session based on a service request received from a network entity or a configuration of the UE.

[0347] Clause 30. A UE as described in any one of clauses 26 to 29, wherein the one or more processors are further configured to: send a first SLPP message to each of the other UEs of the plurality of UEs, the first SLPP message including a request for each UE to join the session; and receive a second SLPP message from each of the other UEs of the plurality of UEs indicating acceptance or rejection of the request.

[0348] Clause 31. A UE as described in any one of clauses 26 to 30, wherein the one or more processors are further configured to include in the first SLPP message at least one of a level 2 group address of the plurality of UEs, an SLPP session ID, or both.

[0349] Clause 32. A UE described in any one of clauses 26 to 31, wherein the one or more processors are further configured to send a third SLPP message to each of the other UEs of the plurality of UEs, the third SLPP message initiating or resuming an SLPP session.

[0350] Clause 33. The UE of any one of clauses 26 to 32, wherein the one or more processors are further configured to include in the third SLPP message at least one of an application level ID for each UE of the plurality of UEs, an SLPP UE ID for each UE of the plurality of UEs, a group encryption key for the plurality of UEs, or any combination thereof.

[0351] Clause 34. A UE as described in any one of clauses 26 to 33, wherein the one or more processors are further configured to send a first SLPP message to at least one UE of the plurality of UEs to terminate a session in at least one UE.

[0352] Clause 35. Sending a first SLPP message to each UE of a second plurality of UEs except the UE, the second plurality of UEs comprising the UE, at least some of the other UEs of the plurality of UEs, and additional UEs not among the plurality of UEs, the first SLPP message including a request for each UE to join the modified session; and when the third plurality of UEs includes at least one UE, sending a second SLPP message to each UE of the third plurality of UEs, the third plurality of UEs including UEs not among the plurality of UEs, the second SLPP message including a request for each UE to join the modified session. the UE described in any one of clauses 26 to 34, wherein the SLPP message includes a request for each UE to join the modified session; receiving from each UE of the second plurality of UEs a third SLPP message indicating whether each UE accepts or rejects the request; if the third plurality of UEs includes at least one UE, receiving from each UE of the third plurality of UEs a fourth SLPP message indicating whether each UE accepts or rejects the request; and sending to each UE, except for UEs of the plurality of UEs that are not among the second plurality of UEs, a fifth SLPP message indicating that the session is to be terminated at each UE.

[0353] Clause 36. The UE of any one of clauses 26 to 35, wherein the one or more processors are further configured to send a sixth SLPP message to each UE of the second plurality of UEs and the third plurality of UEs when each UE accepts the request to join the modified session, the sixth SLPP message initiating the modified session.

[0354] Clause 37. The UE of any one of clauses 26 to 36, wherein the third plurality of UEs does not include a UE.

[0355] Clause 38. A UE as described in any one of clauses 26 to 37, wherein the one or more processors are further configured to: receive a first SLPP message from a second UE of the plurality of UEs, the first SLPP message including a request for the UE to join, terminate, start, modify, or leave a session, or a request for the second UE to join a session; and, when the first SLPP message includes a request for the UE to join or modify a session, or a request for the second UE to join a session, send a second SLPP message to the second UE, the second SLPP message indicating acceptance or rejection of the request.

[0356] Clause 39. A UE as described in any one of clauses 26 to 38, wherein each SLPP message of the plurality of SLPP messages includes at least one of an SLPP session ID, an SLPP transaction ID, a level 2 address of the UE sending the SLPP message, a level 2 address of the UE or group of UEs receiving the SLPP message, information about one or more UEs of the plurality of UEs, the information including an SLPP UE ID for each UE of the one or more UEs of the plurality of UEs, or any combination thereof.

[0357] Clause 40. The UE of any one of clauses 26 to 39, wherein sidelink positioning of the plurality of UEs is performed using at least one of transmitting and measuring sidelink positioning reference signals (SL PRS), real-time kinematics (RTK), transmitting and measuring WiFi signals, transmitting and measuring ultra-wideband (UWB) signals, or any combination thereof.

[0358] Clause 41. A UE as described in any one of clauses 26 to 40, wherein sidelink positioning of the plurality of UEs is performed using RTK, each UE of the plurality of UEs acquires carrier phase measurements of Global Navigation Satellite (GNSS) signals, the carrier phase measurements acquired by the plurality of UEs are provided to at least one UE of the plurality of UEs, and the at least one UE determines location results for the plurality of UEs based on the carrier phase measurements acquired by the plurality of UEs.

[0359] Clause 42. The UE of any one of clauses 26 to 41, wherein sidelink positioning of the plurality of UEs is performed using SL PRS transmission and measurement, and the one or more processors are further configured to: obtain an SL PRS transmission configuration for each UE of the plurality of UEs; obtain SL PRS measurements for other UEs of the plurality of UEs based on the SL PRS transmission configuration for the other UEs; transmit SL PRS based on the SL PRS transmission configuration for the UE; and at least one of transmitting the obtained SL PRS measurements to at least one other UE of the plurality of UEs or receiving the obtained SL PRS measurements from at least one other UE of the plurality of UEs, or both, wherein the obtained SL PRS measurements enable determination of a location result for the target UE.

[0360] Clause 43.SL The UE of any one of clauses 26 to 42, wherein the PRS measurements include at least one of receive time-transmit time difference (Rx-Tx), reference signal time difference (RSTD), round trip signal propagation time (RTT), reference signal received power, reference signal received quality, angle of arrival, or any combination thereof.

[0361] An exemplary UE for sidelink positioning of a plurality of UEs, including a UE, comprises a transceiver, a memory, and one or more processors communicatively coupled to the transceiver and the memory. The one or more processors may be configured to: determine to perform sidelink positioning of the plurality of UEs, where there is no discovery between the UE and at least some of the other UEs of the plurality of UEs; and exchange, using broadcast or groupcast, SLPP messages with the other UEs of the plurality of UEs, where the SLPP messages are not part of a session, and the SLPP messages enable the sidelink positioning.

[0362] Clause 45. The UE of clause 44, wherein the one or more processors are further configured to obtain location results for at least two target UEs of the plurality of UEs, the location results including at least one of a range between each target UE and another UE of the plurality of UEs, a direction to or from each target UE, respectively, to or from another UE of the plurality of UEs, a location of each target UE relative to a location of another UE of the plurality of UEs, a velocity of each target UE relative to a velocity of another UE of the plurality of UEs, an absolute location of each target UE, an absolute velocity of each target UE, or any combination thereof.

[0363] Clause 46. A UE as described in clause 44 or 45, wherein the plurality of SLPP messages includes at least one SLPP message sent by the transmitting UE to another UE among the plurality of UEs, the UE being either the transmitting UE or one of the other UEs, and the at least one SLPP message includes SLPP assistance data for assisting the other UE in transmitting or measuring positioning-related signals, a portion of a measurement result or location result obtained by the transmitting UE, or both, a level 2 address of the transmitting UE, an application level address of the transmitting UE, or any combination thereof.

[0364] Clause 47. The UE of any one of clauses 44 to 46, wherein sidelink positioning of the plurality of UEs is performed using at least one of transmitting and measuring sidelink positioning reference signals (SL PRS), real-time kinematics (RTK), transmitting and measuring WiFi signals, transmitting and measuring ultra-wideband (UBW) signals, or any combination thereof.

[0365] Clause 48. Sidelink positioning of a plurality of UEs is performed using transmission and measurement of SL PRS, and one or more processors receive an SL PRS transmission configuration from another UE of the plurality of UEs; obtain SL PRS measurements for the other UE of the plurality of UEs based on the SL PRS transmission configuration; receive a modified SL PRS transmission configuration from the other UE of the plurality of UEs, the modified SL PRS transmission configuration corresponding to the SL PRS transmitted by the other UE; transmit the obtained SL PRS measurements for the other UE to the other UE of the plurality of UEs; transmit an SL PRS based on the SL PRS transmission configuration for the UE; before transmitting the SL PRS, transmit the SL PRS transmission configuration for the UE to the other UE of the plurality of UEs; after transmitting the SL PRS, transmit the modified SL PRS transmission configuration for the UE to the other UE of the plurality of UEs, the modified SL PRS transmission configuration for the UE corresponding to the transmitted SL PRS; receive the SL PRS measurements obtained by the other UE of the plurality of UEs; 48. The UE of any one of clauses 44 to 47, further configured to: determine location results for some of the target UEs based on at least one of the PRS measurements, a modified SL PRS transmission configuration for other UEs of the plurality of UEs, SL PRS measurements obtained by other UEs of the plurality of UEs, and a modified SL PRS transmission configuration for the UE.

[0366] Clause 49. Sidelink positioning of a plurality of UEs is performed using transmission and measurement of SL PRS, and includes receiving an SL PRS transmission configuration from another UE of the plurality of UEs; obtaining SL PRS measurement values ​​for another UE of the plurality of UEs based on the SL PRS transmission configuration; receiving a modified SL PRS transmission configuration from another UE of the plurality of UEs, the modified SL PRS transmission configuration corresponding to the SL PRS transmitted by the other UE; transmitting the obtained SL PRS measurement values ​​for the other UE to another UE of the plurality of UEs; transmitting an SL PRS based on the SL PRS transmission configuration for the UE; transmitting the SL PRS transmission configuration for the UE to another UE of the plurality of UEs before transmitting the SL PRS; after transmitting the SL PRS, transmitting the modified SL PRS transmission configuration for the UE to another UE of the plurality of UEs, the modified SL PRS transmission configuration for the UE corresponding to the transmitted SL PRS; receiving the obtained SL PRS measurement values ​​for the other UE from another UE of the plurality of UEs; 49. The UE of any one of clauses 44 to 48, further comprising: determining location results for some of the target UEs based on at least one of the PRS measurements, a modified SL PRS transmission configuration for other UEs of the plurality of UEs, SL PRS measurements obtained by other UEs of the plurality of UEs, and a modified SL PRS transmission configuration for the UE.

[0367] Clause 50.SL The UE of any one of clauses 44 to 49, wherein the PRS measurements include at least one of receive time-transmit time difference (Rx-Tx), reference signal time difference (RSTD), round trip signal propagation time (RTT), reference signal received power, reference signal received quality, angle of arrival, or any combination thereof.

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