Sidelink Positioning Protocol (SLPP) Procedures

Abstract

In some implementations, a user equipment (UE) may exchange multiple sidelink (SL) positioning protocol (SLPP) messages with other UEs of the multiple UEs, where the multiple SLPP messages are exchanged via direct wireless SL communication. At least one message of the multiple SLPP messages may include a capability request message, a capability provision message, an assistance data request message, an assistance data provision message, a location information request message, or a location information provision message. The UE may perform positioning based, at least in part, on the multiple SLPP messages. The UE may further exchange SLPP messages with a location server (e.g., an LMF) that may assist the UE in performing the positioning, and the location server may enable the location server to obtain location results for the multiple UEs. SLPP procedures may be defined to manage SL positioning.

Description

[Technical Field]

[0001] Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 370,917, filed August 9, 2022, entitled "SIDELINK POSITIONING PROTOCOL (SLPP) PROCEDURES," and U.S. Provisional Patent Application No. 63 / 377,530, filed September 28, 2022, entitled "SIDELINK POSITIONING PROTOCOL (SLPP) PROCEDURES," all of which are assigned to the same assignee and incorporated herein by reference in their entireties. [Background technology]

[0002] 1. Field of Disclosure The subject matter disclosed herein relates to wireless communication systems, and more particularly to systems, methods, and devices that support positioning.

[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 broadcasts. 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, also known as user equipment (UEs). A base station may communicate with a set of UEs over 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). Additionally, the UEs may communicate directly with each other using sidelink channels.

[0005] The location of a UE may be useful or necessary for several applications, including emergency calling, navigation, direction finding, asset tracking, and Internet services. For example, in a cellular network, a base station may send downlink reference signals using which positioning measurements are obtained by the UE and / or the UE may send uplink reference signals 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 allow two or more UEs to perform positioning (including ranging) using sidelink communications. However, many aspects of sidelink-based procedures have not yet been formalized. Summary of the Invention

[0007] A method for positioning a plurality of user equipments (UEs) using sidelink (SL) communications according to the present disclosure includes exchanging a plurality of SL Positioning Protocol (SLPP) messages, the plurality of SLPP messages being exchanged via direct wireless SL communications, at least one of the plurality of SLPP messages including a capability request message from a first UE of the plurality of UEs requesting capability to support positioning using SL communications from one or more additional UEs of the plurality of UEs, at least one of the plurality of SLPP messages including a capability provision message indicating a capability for at least one of the one or more additional UEs to support positioning using SL communications, and at least one of the plurality of SLPP messages including The method may include exchanging a plurality of SLPP messages with other UEs of the plurality of UEs, the plurality of SLPP messages including a Provide Assistance Data message including data for one or more additional UEs of the plurality of UEs, the data assisting the one or more additional UEs in performing positioning using SL communication, at least one message of the plurality of SLPP messages including a Request Location Information message by the first UE requesting location measurements for positioning using SL communication from one or more additional UEs of the plurality of UEs, and at least one message of the plurality of SLPP messages including a Provide Location Information message providing location measurements for positioning using SL communication by at least one of the one or more additional UEs. The method may also include performing positioning based, at least in part, on the plurality of positioning messages.

[0008] An exemplary method of positioning using sidelink (SL) communication at a first user equipment (UE) according to the present disclosure may include transmitting one or more capability request messages from the first UE to one or more additional UEs via direct wireless SL communication, each capability request message including a request for a SL position reference signal (SL-PRS) configuration and one or more capabilities to support SL-PRS measurements. The method may also include receiving, at the first UE from the one or more additional UEs via direct wireless SL communication, one or more capability provision messages in which the one or more additional UEs respond to the one or more capability request messages. The method may also include obtaining an SL-PRS configuration for each of the one or more additional UEs based, at least in part, on the one or more capability provision messages. The method may also include transmitting, from the first UE to the one or more additional UEs via direct wireless SL communication, one or more assistance data provision messages including the SL-PRS configuration for each of the one or more additional UEs.

[0009] An example method for enabling a first user equipment (UE) to coordinate positioning using sidelink (SL) communication according to the present disclosure may include receiving, via direct wireless SL communication, at a second UE from the first UE, a capability request message including a request for one or more capabilities to support SL position reference signals (SL-PRS) and SL-PRS measurements, where the second UE is one of one or more additional UEs other than the first UE used for positioning using SL communication. The method may also include transmitting, via direct wireless SL communication, from the second UE to the first UE, a capability provision message in response to the capability request message. The method may also include receiving, via direct wireless SL communication, at the second UE from the first UE, an assistance data provision message including an SL-PRS configuration for the second UE, where the SL-PRS configuration is based, at least in part, on the capability provision message.

[0010] An exemplary user equipment (UE) according to the present disclosure includes one or more transceivers, one or more memories, and one or more processors communicatively coupled to the one or more transceivers and the one or more memories, the one or more processors configured to exchange a plurality of Sidelink (SL) Positioning Protocol (SLPP) messages with other UEs of the plurality of UEs via the one or more transceivers, the plurality of SLPP messages being exchanged via direct wireless SL communications, at least one of the plurality of SLPP messages including a capability request message from a first UE of the plurality of UEs requesting capability to support positioning using SL communications from one or more additional UEs of the plurality of UEs, and at least one of the plurality of SLPP messages including a capability request message from a first UE of the plurality of UEs requesting capability to support positioning using SL communications from one or more additional UEs of the plurality of UEs. At least one of the plurality of SLPP messages includes a capability providing message indicating a capability to support positioning using SL communication, at least one message of the plurality of SLPP messages includes a provide assistance data message including data for one or more additional UEs of the plurality of UEs, the data assisting the one or more additional UEs in performing positioning using SL communication, at least one message of the plurality of SLPP messages includes a location information request message by the first UE to request location measurements for positioning using SL communication from one or more additional UEs of the plurality of UEs, and at least one message of the plurality of SLPP messages includes a provide location information message providing location measurements for positioning using SL communication by at least one of the one or more additional UEs. The one or more processors may also be configured to perform positioning based, at least in part, on the plurality of positioning messages.

[0011] An exemplary first UE according to the present disclosure may comprise one or more transceivers, one or more memories, and one or more processors communicatively coupled to the one or more transceivers and the one or more memories, the one or more processors configured to: send one or more capability request messages via the one or more transceivers to one or more additional UEs via direct wireless SL communication, each capability request message including a request for one or more capabilities to support an SL position reference signal (SL-PRS) configuration and SL-PRS measurements. The one or more processors may be further configured to receive one or more capability provision messages from the one or more additional UEs via the direct wireless SL communication via the one or more transceivers, in which the one or more additional UEs respond to the one or more capability request messages. The one or more processors may be further configured to obtain an SL-PRS configuration for each of the one or more additional UEs based at least in part on the one or more capability provision messages. The one or more processors may be further configured to send, via the one or more transceivers, via direct wireless SL communication to the one or more additional UEs, one or more provide assistance data messages including an SL-PRS configuration for each UE of the one or more additional UEs.

[0012] An exemplary second UE according to the present disclosure may comprise one or more transceivers, one or more memories, and one or more processors communicatively coupled to the one or more transceivers and the one or more memories, wherein the one or more processors are configured to receive a capability request message from the first UE via the one or more transceivers via direct wireless SL communication, the capability request message including a request for one or more capabilities to support SL position reference signal (SL-PRS) configuration and SL-PRS measurements, the second UE being one of one or more additional UEs other than the first UE used for positioning using SL communication. The one or more processors may be further configured to send a capability provision message in response to the capability request message to the first UE via the one or more transceivers via direct wireless SL communication. The one or more processors may be further configured to receive, via the one or more transceivers from the first UE via direct wireless SL communication, an assistance data provision message including an SL-PRS configuration for the second UE, wherein the SL-PRS configuration is based at least in part on the capability provision message.

[0013] An exemplary user equipment according to the present disclosure may include one or more transceivers, one or more memories, and one or more processors communicatively coupled to the one or more transceivers and the one or more memories and configured to perform any of the aforementioned methods.

[0014] An exemplary apparatus according to the present disclosure may comprise means for carrying out any of the aforementioned methods.

[0015] According to this disclosure, an exemplary non-transitory computer-readable medium stores instructions comprising code for performing any of the aforementioned methods.

[0016] 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]

[0017] [Figure 1] The architecture of a communication system including several UEs, a Radio Access Network (RAN), and a 5G Core Network (5GC) is shown. [Figure 2] 1 shows a communication system architecture for network-supported sidelink positioning. [Figure 3] 10 is a signal flow illustrating signaling between a UE and a location server for network-supported sidelink positioning. [Figure 4A] 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] 1 is a signal flow illustrating signaling between a pair of UEs for pair-wise sidelink positioning. [Figure 6A] 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] 1 is a signal flow illustrating signaling between UEs for positioning signal configuration and confirmation exchange. [Figure 6C]1 is a signal flow illustrating signaling between UEs for measurement exchange. [Figure 7] 10 is a signal flow illustrating signaling for group operation of sidelink positioning for multiple UEs. [Figure 8] FIG. 10 is a signal flow diagram of an embodiment of an SLPP positioning session between UEs in UE-based or “autonomous” mode. [Figure 9] FIG. 10 is a signal flow diagram of an embodiment of an SLPP positioning session between UEs in UE-based or “autonomous” mode. [Figure 10] FIG. 10 is a signal flow diagram of an embodiment of a SLPP positioning session in network-assisted mode. [Figure 11] FIG. 10 is a signal flow diagram of an embodiment of a SLPP positioning session in network-assisted mode. [Figure 12] FIG. 10 is a signal flow diagram of an embodiment of a SLPP positioning session in network-assisted mode. [Figure 13] 1 is a flow diagram of a method for positioning multiple UEs using SL communications, according to one embodiment. [Figure 14] 1 is a flow diagram of a method for positioning using SL communication in a first UE according to one embodiment. [Figure 15] 1 is a flow diagram of a method for enabling a first UE to coordinate positioning using SL communication according to one embodiment. [Figure 16] FIG. 2 is a block diagram of an embodiment of a UE. [Figure 17] FIG. 1 is a block diagram of one embodiment of a computer system. [Figure 18] FIG. 1 is a signal flow diagram of an example of acknowledgement and retransmission capabilities for SLPP messages that may be utilized in accordance with some embodiments. [Figure 19] 1 is a signal flow diagram of an example SLPP procedure that may include SLPP message redundancy that may be utilized in accordance with some embodiments. [Figure 20]1 is a signal flow diagram of an exemplary hybrid positioning method that utilizes SL positioning in conjunction with Uu positioning to provide hybrid (or "joint") Uu and SL positioning for a group of UEs, according to one embodiment.

[0018] 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

[0019] 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 pair-wise positioning, group operation, and network-supported SLPP.

[0020] 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.

[0021] 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 a particular 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," 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.

[0022] 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.

[0023] A UE may be embodied by any of several types of devices, including, but not limited to, a printed circuit (PC) card, a CompactFlash 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.

[0024] 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.

[0025] 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 distance 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.

[0026] 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, and procedures 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 those of traditional LPP positioning of UEs in which the UE exchanges uplink and / or downlink signals with one or more base stations.

[0027] 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 as UEs 105 or collectively referred to as UEs 105 herein. 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 also 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 constellation 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.

[0028] 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 bidirectionally wirelessly 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.

[0029] 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.

[0030] 1 shows a 5G-based network, similar network implementations and configurations may be used for other communication technologies such as 3G, Long Term Evolution (LTE), 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.

[0031] 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).

[0032] 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 communications, multiple frequencies of Wi-Fi communications, satellite positioning, satellite communications, one or more types of communications (e.g., Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Long Term Evolution (LTE)), V2X (e.g., V2P (vehicle-to-pedestrian), V2I (vehicle-to-infrastructure), V2V (vehicle-to-vehicle), etc.), IEEE 802.11p, etc.). V2X communications may be implemented using cellular (Cellular-V2X, C-V2X) and / or Wi-Fi (e.g., Dedicated Short-Range Radio Communication (DSRC)). 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 sent 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), or a sidelink sounding reference signal (SL-SRS).

[0033] 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 by some other name. Furthermore, the UE 105 may correspond to a cell phone, a smartphone, a laptop, a tablet, a PDA, a tracking device, a navigation device, an Internet of Things (IoT) device, an asset tracker, a health monitor, a security system, a smart city sensor, a smart meter, a wearable tracker, or some other portable or movable device. Typically, although not necessarily, the UE 105 may support wireless communications 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), etc. The UE 105 may also 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 UE 105 to communicate with external client 130, server 121, and / or server 123 (e.g., via elements of 5GC 140 and possibly the Internet 122) and / or enable external client 130, server 121, and / or server 123 to receive location-related information regarding UE 105 (e.g., via GMLC 125, SLP 119, or UPF 118).

[0034] 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 a UE, e.g., UE 105 location, may be referred to as a location, location estimate, location fix, fix, position, position estimate, or position fix, and may be geographic 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 UE location 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 UE location may be expressed as an area or volume (defined either geodesically 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.

[0035] 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.

[0036] 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 a 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 not be able 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. A 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 not be able 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. A 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.

[0037] 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.

[0038] 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, which 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.

[0039] 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.

[0040] The base station 110a, 110b, 114 may configure PRS transmissions on one or more PRS resources of the channel. The PRS resources 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, the PRS resources 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 the PRBs of the channel.

[0041] 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).

[0042] The UE 105 may receive a PRS transmission over one or more PRS resources of the slot. The UE 105 may determine reporting parameters for at least some of the PRS resources included in the transmission. The reporting parameters (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).

[0043] 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.

[0044] 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 station(s) 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).

[0045] 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), while downlink-and-uplink-based positioning methods include, for example, Round Trip Time (RTT) with one or more neighbor base stations. Furthermore, 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.

[0046] As noted, while FIG. 1 illustrates nodes configured to communicate according to a 5G communication protocol, nodes configured to communicate according to other communication protocols, such as, for example, an LTE protocol or an IEEE 802.11x protocol, 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 5G Node B 140.

[0047] The gNBs 110a, 110b, and ng-eNBs 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 for 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 involved in supporting signaling connections to the UE 105.

[0048] 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 from the LMF 120 (e.g., including a location estimate or sidelink location result for the UE 105) 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 as 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.

[0049] 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.

[0050] 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.

[0051] 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 the 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 a 5G Non-Access Stratum (NAS) protocol.

[0052] 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 of 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.

[0053] 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 SV190.

[0054] 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).

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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 SRS) transmitted by the UE 105 for measurement by the gNB 110, for example, as described above. Measurements of the SL PRS or SL SRS signal 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, SL AOD, or any combination thereof.

[0059] In some scenarios, a group of UEs (not shown in FIG. 1 ) may support SL positioning. In this case, one UE in the group may transmit an SL PRS or SL SRS signal that can be measured by some or all of the other UEs in the group. Some or all of the other UEs in the group may also transmit an SL PRS or SL SRS signal, respectively, that can be measured by some or all of the other UEs in the group differently from the UE transmitting the UL PRS or UL SRS (e.g., each UE transmits the SL SRS or SL PRS at one or more times different from the times at which other UEs in the group transmit the SL PRS or SL SRS). Measurements made by the UEs applicable to the SL PRS or SL SRS transmission by the group of UEs may include Rx-Tx, TOA, RSTD, AOA, RSRP, RSRQ, or any combination thereof. Positioning methods supported by these measurements may include sidelink RTT (e.g., ranging), sidelink AOA, sidelink AOD, sidelink TDOA (SL-TDOA), or any combination thereof. Based on the measurements and the positioning method(s), each UE may determine a location result for itself and / or one or more other UEs in the group. As mentioned above, the location result for a UE may include the range or distance between the UE and each of the one or more other UEs in the group, the direction from the UE to each of the one or more other UEs in the group, the direction from each of the one or more other UEs in the group to the UE, the location of the UE relative to the locations of any other UEs in the group, the location of the UE relative to some other known location, the absolute location of the UE, the velocity of the UE, or the velocity of the UE relative to some other UEs.

[0060] 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. For 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 and, later, non-PRS methods such as RTK. By allowing the addition of new capabilities and methods later, SLPP may avoid the need to define a new positioning protocol separate from SLPP. For example, additional positioning methods that may later be included in SLPP may include RTK, Wi-Fi, Ultra-Wideband (UWB), and Bluetooth positioning methods. 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 the 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 for 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 transferred and used by various entities, such as UEs, RSUs, PRUs, and location servers such as LMFs and SUPL SLPs. Location server (e.g., LMF and SUPL SLP) uses 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) uses 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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, for example, use one or more specific signal types (e.g., SL NR PRS, SL LTE PRS, Wi-Fi, GPS L1-L5, or any combination thereof) and support one method of determining location for the specific signal types (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] 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 the 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 the 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).

[0080] Figure 4B is a block diagram 400B illustrating another implementation of the structure of an SLPP message 420. Similar to block diagram 400A of Figure 4A, SLPP message 420 includes a header 422 that may contain information similar to header 412 in Figure 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 SLPP message 420, each containing that UE's parameters for each positioning method / type 1 through M supported by that UE.

[0081] Figure 5 is a signal flow 500 illustrating, by way of example, signaling between UE 105A and UE 105B for pair-wise sidelink positioning involving only two UEs. UE 105A and UE 105B may be, for example, the UEs shown in Figure 1 or any two of the UEs shown in group 210 shown in Figure 2. The sidelink positioning shown in Figure 5 may be network independent, and therefore the UEs shown in Figure 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 Figure 2.

[0082] In stage 0 of FIG. 5, UE discovery and establishment of a sidelink communication session or a sidelink positioning session are performed. The discovery process can be request-response or announcement-based. The discovery phase can 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 can 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 can broadcast a discovery-based message using sidelink signaling, and the UE 105B can receive the discovery-based message and respond by sending a similar discovery-based response message back to the UE 105A using sidelink signaling. Additional messages can be exchanged between the UE 105A and the UE 105B to 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.

[0083] 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.

[0084] 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.

[0085] The service requirements exchanged in stage 1 may include an indication of at least one of: an immediate (e.g., single) location at the current time, a deferred location (e.g., at a later time), a periodic location, a triggered location, one or more types of location results (e.g., relative location, global location, range, direction), a QoS of the location results (e.g., location result accuracy, location result response time or latency, location periodicity, location reliability), or any combination thereof. The exchanged service requirements may define the type(s) of location (e.g., single or periodic), accuracy, latency, periodicity, reliability, or any combination thereof, that each UE requires or expects in the sidelink positioning session.

[0086] 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.

[0087] 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.

[0088] 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 RTT, Rx-Tx, RSRP, RSRQ, AOA, AOD, or TOA of the PRS1 transmitted by UE 105A.

[0089] 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 measure, for example, one or more of the RTT, Rx-Tx, RSRP, RSRQ, AOA, AOD, or TOA of the PRS2 transmitted by UE 105B.

[0090] In step 6, UE 105A and UE 105B exchange measurements obtained in steps 4 and 5. The exchange of measurements may indicate the exact SL PRS configuration to be used in step 4 or step 5 for transmission of the SL PRS, and may further provide the measurements generated in step 4 or step 5, for example, if there were any differences to the PRS1 and / or PRS2 configurations (e.g., with respect to the exact time or duration of the SL PRS transmission). As an example, if the SL positioning signal (SL PRS) transmitted by UE 105A in step 4, which corresponds to the PRS1 configuration sent by UE 105A in step 2, does not exactly match the PRS1 configuration (e.g., because UE 105A slightly delayed its SL PRS transmission because some other UE was transmitting at the transmission time(s) indicated in the PRS1 configuration), UE 105A may include the transmission time(s) actually used by UE 105A in step 4 as part of the measurements sent by UE 105A in step 6. UE 105B may then use the correct transmit time(s) for UE 105A received in step 6 when calculating any location results later (e.g., in step 7). Exchanging measurements in step 6 may include both UE 105A and UE 105B sending their measurements to the other UE, or only one of UE 105A or UE 105B sending their measurements to the other UE.

[0091] In step 7, UE 105A and UE 105B may each calculate a location result, e.g., a distance and / or direction, a relative location, an absolute location, a velocity, a relative velocity, or any combination thereof, between UE 105A and 105B based on the measurements generated in steps 4 and 5 and received 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).

[0092]

number

[0093] The location result(s) 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 their location results to the other UE. In the latter case, only the UE that sends its location result to the other UE may calculate its location result in step 7.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] The pair-wise 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 be small enough to allow direct discovery and direct sidelink signaling between the UEs in the group. The various sidelink positioning messages transmitted by the 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.

[0104] FIG. 7 is a signal flow 700 illustrating signaling for group operation of sidelink positioning for multiple UEs, shown by way of example as UEs 105A, 105B, 105C, ..., 105Z, sometimes collectively referred to as UEs 105. The group of UEs 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).

[0105] In stage 0 of FIG. 7, UE discovery, 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 the discovery-based message and respond by each sending a similar discovery-based response message back to UE 105A using sidelink signaling. The UEs 105 may also exchange (or may 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 establish sidelink communications or positioning sessions between UEs 105. For example, UE 105A may multicast a single request (e.g., SLPP Request) to initiate an SLPP positioning session to UEs 105B, 105C, and 105Z, and UEs 105B, 105C, and 105Z may return responses (e.g., SLPP Response) to UE 105A agreeing to initiate the SLPP positioning session.

[0106] 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 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 positioning 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.

[0107] In stage 2, UE 105A may send proposed positioning signal configurations, e.g., PRS1, PRS2, PRS3, ... PRSn configurations, 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.

[0108] 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(s) are being rejected. UE 105A may then propose a different positioning signal configuration (or simply a different PRS configuration for the rejected PRS configuration(s)) 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, when the PRS1, PRS2, PRS3, ... PRSn configuration sent in stage 2 is acceptable to each of UEs 105B, 105C, ... 105Z, stage 3 may be omitted, which may reduce signaling.

[0109] 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, UE 105C, ... UE 105Z may each measure, for example, one or more of the RTT, Rx-Tx, RSRP, RSRQ, AOA, AOD, and TOA of the PRS1 transmitted by UE 105A.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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 the correct or corrected 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.

[0114] In step 9, each UE 105 determines a location result, e.g., distance 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, or any combination thereof, of one or more of the UEs 105, based on the measurements generated in steps 4-7 and received in step 8. In some embodiments, only one UE 105 (e.g., UE 105A) may determine the location result.

[0115] The location result(s) 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) transmitting its location result to the other UEs 105. In the latter case, only the UEs 105 that transmit their location result to the other UEs 105 may calculate their location result in step 9.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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. 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.

[0120] 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.

[0121] 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, modification of group UEs may be necessary when UEs move in and out of a group area.

[0122] 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 UEs that are generally farther from other UEs in the group than a maximum distance threshold; a time restriction, e.g., that excludes from the group any UEs that are 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 UEs that are 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 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, for example, 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.

[0123] FIG. 8 is a signal flow diagram illustrating four UEs (UEs A, B, C, and D) engaged in an SLPP positioning session 800 without the support of a location server such as an LMF. As with other figures provided herein, FIG. 8 is provided as a non-limiting example, and other embodiments may add, omit, and / or rearrange some of the illustrated operations. Here, a device and service discovery process may take place as shown in block 805, in which the UEs may discover each other and / or each UE may determine whether it has network service. In some embodiments, the device and service discovery process (of any of FIGS. 8-12) may be followed by a potential SLPP session establishment (not shown).

[0124] After the device and service discovery process, a sidelink positioning and ranging function (SPRF) process 807 may begin in which the initiating UE (UE B in the example of FIG. 8, which may function as a coordinating UE) may broadcast or multicast an SLPP Capability Request message, as indicated by arrow 810, to request UE positioning capabilities from UEs A, C, and D. As used in the figures herein, a double-sided arrow, such as arrow 810, may indicate a transmission to multiple receiving devices (e.g., from one UE to all other UEs), including a broadcast or multicast transmission. However, it should be noted that alternative embodiments may similarly transmit a message to each of multiple receiving devices using a unicast transmission (e.g., a separate unicast transmission for each receiving device). It should be noted that UE B may be referred to as the "initiating UE," "coordinating UE," "anchor UE," "target UE," or "server UE."

[0125] The addressed UEs may then respond by each multicasting (or possibly broadcasting or unicasting) an SLPP Provide Capability message containing their UE Positioning Capabilities, as indicated by arrow 815. Each UE's UE Positioning Capabilities may include details of the UE's supported SL-PRS configurations and supported SL-PRS measurements. Taking the received UE capabilities into account, UE B may then (in this example) determine an SL-PRS configuration that can be broadcast and measured by all UEs and multicast an SLPP Provide Assistance Data message, as indicated by arrow 820, to deliver the determined SL-PRS configuration to the UEs participating in this session. Following this, UE B may send an SLPP Location Information Request message, as indicated by arrow 825, to request specific SL-PRS measurement(s) from UEs A, C, and D. Each of the participating UEs (including the initiating UE B in FIG. 8) may then broadcast an SL-PRS according to its own SL-PRS configuration (e.g., at a different time than the SL-PRS transmitted by the other UEs) and perform the requested measurements of the SL-PRS broadcast by the other participating UEs, as shown in block 830. For example, in block 830a, UE A may transmit an SL-PRS according to its SL-PRS configuration and measure the SL-PRS transmitted by UEs B, C, and D, transmitted in blocks 830b, 830c, and 830d, respectively. (The other UEs have similar functionality in block 830.)

[0126] Once measurements are complete, all UEs (except initiator UE B) may then each multicast (or possibly broadcast or unicast) an SLPP Provide Location Information message, as indicated by arrow 835, which initiator UE B uses to determine the distance and / or position of the group of UEs, as indicated by block 840. For example, the position / distance calculation in block 840 may include obtaining location results (e.g., relative locations, directions, and / or distances) for UEs A, B, C, and D. In some instances, initiator UE B may optionally distribute the obtained UE distances / locations to other UEs in the group, as indicated by dashed arrow 845. (As used herein, dashed arrows may represent optional functionality.) The transmission of a final SLPP Provide Location Information message by UE B may not be requested by the other UEs but may still be permissible according to applicable transaction rules for SLPP.

[0127] The procedure of FIG. 8 may be referred to as centralized UE location or “UE-assisted” UE location because one UE (UE B) may obtain location or location information for other UEs and then transmit this to the other UEs.

[0128] FIG. 9 is a signal flow diagram illustrating another exemplary SLPP positioning session 900. As with the SLPP positioning session 800 of FIG. 8, UE B is the initiator, and many of the initial actions are the same. However, in FIG. 9, each UE in the group, including initiating UE B, may broadcast its SL-PRS measurements to all other UEs in the group (e.g., via multicast) using an SLPP Provide Location Information message at arrow 910. This may enable each UE in the group to perform distance or position calculations, as indicated at block 920. Each UE may then optionally transmit the distance or position calculations it determined at block 920 to the other UEs in the group, as indicated at arrow 930.

[0129] The procedure of Figure 9 may be referred to as distributed or decentralized UE location or "UE-based" UE location because each UE may obtain location and location information for both itself and other UEs and then transmit this to other UEs.

[0130] According to some embodiments, two or more UEs may use SLPP with location server support to support ranging and positioning in a network-assisted mode. For example, this may be possible when at least one UE is in network coverage and is enabled to access a PLMN via a subscription. In this mode, UEs with PLMN access may be assisted by a location server (e.g., LMF) to use SLPP or may be requested by a location server to employ SLPP to obtain a mobile terminal location request (MT-LR) location result. In some instances of this network-assisted mode, for example, when some UEs are out of coverage, not all UEs may have PLMN access and be supported or provide support for it by the location server. Therefore, location server support may be limited to only some UEs within a group of UEs participating in an SLPP positioning session. Figures 10-12, described in more detail below, illustrate how positioning in such a network-assisted mode may be performed.

[0131] FIG. 10 shows an exemplary SLPP positioning session 1000 in which a Location Server (LS) (e.g., LMF) acts as an adjunct to an initiating UE B to assist UE B in performing sidelink positioning. Similar to the sessions of FIGS. 8 and 9 , there may be a device and service discovery process, as indicated by block 1005, followed by an SPRF 1010. The SPRF 1010 may begin with the initiating UE (UE B) multicasting (or broadcasting) an SLPP Capability Request message, as indicated by arrow 1015, to request sidelink positioning capabilities from the other participating UEs, which each respond with an SLPP Capability Provide message, as indicated by arrow 1020. The initiating UE B may then request SL-PRS configuration information from the LS via an SLPP Request Assistance Data, as indicated by arrow 1025, and the LS may respond with an SLPP Provide Assistance Data message, as indicated by arrow 1035, which may include the SL-PRS configuration for all UEs. In some embodiments, to enable the LS to determine an appropriate SL-PRS configuration for all UEs, UE B may also provide the LS with the obtained SL-PRS capabilities of all UEs in the group in an SLPP Capability Provision message, indicated by optional arrow 1030. (As shown in FIG. 10, this message may precede the SLPP Request Assistance Data message of arrow 1025.)

[0132] The SLPP positioning session 1000 may then proceed in a manner similar to the SLPP positioning method 800 of FIG. 8 to deliver assistance data, perform SL-PRS measurements, and deliver location information. In particular, UE B may transmit the SL-PRS configuration received from the LS to another UE in the group in an SLPP Provide Assistance Data message, indicated by arrow 1040, followed by an SLPP Request Location Information message, indicated by arrow 1045. The transmission of the SL-PRS measurements and measurements at block 1050 and the transmission of the measurement results in an SLPP Provide Location Information message at arrow 1055 may be similar to the corresponding operations in FIG. 8 above. As indicated by dashed block 1060, UE B may perform distance / location calculations using the measurement results received from the other UEs. Alternatively, UE B may provide location measurements obtained from all UEs in the group to the LS in an SLPP Provide Location Information message, indicated by arrow 1065, for distance / location calculations performed in the LS, indicated by block 1070. In instances where the LS performs the distance / position calculation, the LS may then return the calculated distance / position to the initiating UE B in an SLPP Provide Location Information message, as indicated by arrow 1075. The SLPP transaction initiated by UE B towards the LS may be part of a location session between UE B and the LS (e.g., mimicked by a Mobile Originated Location Request (MO-LR) or new supplementary service operation).

[0133] FIG. 11 illustrates another exemplary SLPP positioning session 1100 in network-assisted mode. In this example, the LS initiates a sidelink positioning operation with a coordinating UE (UE B) to obtain a mobile-terminated location request (MT-LR) location result. In this example, the coordinating UE (UE B) is the UE that coordinates obtaining SL-PRS configurations and reporting measurement results for a group of UEs participating in the SLPP positioning session 1100. The LS may request the location of the coordinating UE and / or any UE (or all UEs) in the group. In some embodiments, the MT-LR triggering the request from the location server to the coordinating UE may be triggered by an external client or application function (AF) (e.g., external client 130 in FIG. 1 ), which may provide all the necessary information for the MT-LR to the LS (e.g., to the LMF via GMLC and AMF). The LS may first request sidelink positioning capabilities for UE B, or possibly for another UE (e.g., UE A, C, D), from UE B via an SLPP Capability Request message, indicated by arrow 1105, to which the adjusting UE may respond with an SLPP Capability Provide message, as indicated by arrow 1110. The LS may then request location results from UE B using a Supplementary Service Action Request, indicated by arrow 1115. According to some embodiments, the supplementary service action request may indicate, for example, the type of location result requested (e.g., location of one or more of the adjusting UE and / or other UEs), the identities and / or addresses of specific other UEs involved (e.g., UE A, C, D), or whether any UEs can be used, whether a single set of location results is requested (immediate location) or whether deferred (e.g., periodic or triggered) location results are requested, or any combination thereof. The supplementary service request may also include an embedded SLPP Location Information Request message indicating specific SLPP location results or measurements provided by the adjusting UE, and / or an embedded SLPP Provide Assistance Data message for providing the adjusting UE with assistance data for SLPP positioning (e.g., SL-PRS configuration).

[0134] According to some embodiments, the reason for using a supplementary service request (at arrow 1115) may be to allow for the inclusion of information such as UE address and identity and the use of immediate versus deferred location that may not be suitable for inclusion in an SLPP message. However, according to some embodiments, it is possible that an SLPP message (e.g., an SLPP Location Information Request) may be used instead. The target UE may then confirm or acknowledge the supplementary service request with a supplementary service response, indicated by arrow 1120, which may indicate whether any requested UEs are available (e.g., whether UEs A, C, and D have been discovered by target UE B). The adjusting UE may then perform SLPP positioning using operations of process 1125 to obtain measurements and location results without further LS assistance. As can be seen, the operations of process 1125 mirror the operations in SLPP positioning session 800 of FIG. 8, as described above. Alternatively, the adjusting UE may initiate a process that echoes the operations in SLPP positioning session 900 of FIG. 9, as described above. At the end of process 1125, the adjusting UE may optionally perform a position calculation (shown in block 1130), in which case the adjusting UE may then provide the calculation results in an SLPP Provide Location Information message, shown at arrow 1135. Otherwise, the adjusting UE may return measurements to the LS in an SLPP Provide Location Information message at arrow 1135, in which case the LS may then determine the location (or distance and / or bearing) for the adjusting UE and / or other UEs, as shown in block 1140. In either case, the LS may then provide the location determination to an external client or AF (not shown). For deferred (periodic or triggered) location, SLPP positioning by the adjusting UE and returning location results to the LS may be repeated.

[0135] Figure 12 illustrates an SLPP positioning session 1200 similar to Figure 11. However, in Figure 12, the LS actively assists SLPP positioning of four UEs, as in Figure 10. That is, the SLPP positioning session 1200 of Figure 12 may proceed in a manner similar to the session of Figure 11, as previously described. However, in Figure 12, process 1205 may include operations indicated by arrows 1210, 1215, and 1220, which may be similar to the operations indicated by arrows 1025, 1030, and 1035 in Figure 10, as previously described. The position calculation at block 1225, the SLPP location information provision at arrow 1230, and / or the position calculation at block 1235 may be performed in a manner similar to the corresponding steps of Figure 11, as previously described.

[0136] In some embodiments, the LS may indicate to the coordinating UE whether the LS should be used for such active assistance. For example, according to some embodiments, the LS indicates in the supplementary service request (arrow 1240) whether assistance of the LS is not preferred, as in FIG. 11, or whether assistance is preferred (or required), as in FIG.

[0137] It should be noted that although the procedures shown in Figures 8-12 are described herein as an SLPP positioning "session," embodiments are not so limited. In alternative embodiments, the procedures shown in Figures 8-12 may not necessarily occur within an SLPP positioning session (e.g., using an established session ID, etc.). Some operations of the procedures (e.g., communications between the initiating / adjusting UE and the LS) may occur outside of an SLPP positioning session, while other operations may occur within the SLPP positioning session (e.g., communications between UEs, such as operations within an SPRF).

[0138] Depending on the desired functionality, embodiments may utilize SL positioning in conjunction with Uu positioning (e.g., in conjunction with one or more base stations) to provide hybrid Uu and SL positioning. An example of such a hybrid positioning method is described with respect to Figure 20, described below.

[0139] 13 is a flow diagram of a method 1300 for positioning multiple UEs using SL communications, according to one embodiment. The functions illustrated in the blocks of method 1300 may be performed, for example, by one UE of the multiple UEs. Exemplary software and / or hardware components of a UE that may be used to perform these functions are shown in FIG. 16, described below.

[0140] In block 1310, the function includes exchanging a plurality of SLPP messages with other UEs of the plurality of UEs, the plurality of SLPP messages being exchanged via direct wireless SL communication, at least one message of the plurality of SLPP messages including a capability request message, where a first UE of the plurality of UEs requests capability to support positioning using SL communication from one or more additional UEs of the plurality of UEs, at least one message of the plurality of SLPP messages including a capability provision message, where at least one of the one or more additional UEs indicates capability to support positioning using SL communication, and at least one message of the plurality of SLPP messages including a capability provision message, where at least one of the one or more additional UEs indicates capability to support positioning using SL communication. The SLPP messages may include a Provide Assistance Data message including data for one or more additional UEs of the plurality of UEs, the data assisting the one or more additional UEs in performing positioning using SL communication; at least one message of the plurality of SLPP messages includes a Request Location Information message, in which the first UE requests location measurements for positioning using SL communication from one or more additional UEs of the plurality of UEs; and at least one message of the plurality of SLPP messages includes a Provide Location Information message, in which at least one of the one or more additional UEs provides location measurements for positioning using SL communication. Examples of how multiple SLPP messages may be exchanged, including a Request Capability message, a Provide Capability message, a Provide Assistance Data message, a Request Location Information message, and / or a Provide Location Information message, are described above with respect to Figures 8-12.

[0141] According to some embodiments, the exchange of the SLPP messages and the performance of the positioning may occur within the SLPP positioning session and / or may be part of a positioning procedure or transaction separate from the SLPP positioning session. In some embodiments of method 1300, the first UE may send a provide assistance data message to one or more additional UEs of the plurality of UEs. In such embodiments, the content of the provide assistance data may be based at least in part on configuration information received by the first UE from the server. The configuration information received by the first UE from the server may be based at least in part on capability information provided by the first UE to the server, the capability information being based at least in part on the provide capability message. According to some embodiments, prior to the exchange of the SLPP messages with other UEs of the plurality of UEs, the first UE may exchange a plurality of announcing SLPP messages with the server, and the exchange of the plurality of SLPP messages with other UEs of the plurality of UEs is based on the exchange of the plurality of announcing SLPP messages. In such embodiments, the announcing SLPP messages may include a capability request message from the server. Additionally or alternatively, the announcing SLPP messages may include a location information request message from the server. In such an embodiment, the location request may be included in the supplementary service request message.

[0142] The means for performing the functions in block 1310 may comprise a bus 1605, a processor(s) 1610, a digital signal processor (DSP) 1620, a wireless communication interface 1630 (e.g., a transceiver), a memory 1660, and / or other components of the UE 1600, as shown in FIG. 16 described below.

[0143] The functionality in block 1320 may include, at least in part, performing positioning based on the plurality of positioning messages. As described previously herein with reference to Figures 8-12, an initiating or adjusting UE may perform one or more position calculations based on measurements made during a positioning session. As described with respect to these figures, these measurements may be coordinated by such initiating or adjusting UE and provided to such initiating or adjusting UE by other UEs using the various messages described in block 1310.

[0144] The means for performing the functions in block 1320 may comprise a bus 1605, a processor(s) 1610, a DSP 1620, a wireless communication interface 1630 (e.g., a transceiver), a memory 1660, and / or other components of the UE 1600, as shown in FIG. 16 described below.

[0145] As shown in the above-described embodiments, one or more of the following features may be included based on desired functionality. According to some embodiments, the direct wireless SL communication uses user plane signaling or control plane signaling. According to some embodiments, method 1300 may include engaging in a discovery process (e.g., as shown in FIGS. 8-12) to determine one or more of the other UEs to participate in the positioning before exchanging SLPP messages. According to some embodiments of method 1300, the SLPP messages may include a unicast message sent to one UE of the plurality of UEs, a multicast message sent by one UE of the plurality of UEs to all other UEs of the plurality of UEs, a broadcast message sent to one UE of the plurality of UEs and to UEs that are not in the plurality of UEs, or any combination thereof. Additionally or alternatively, the UE (e.g., performing method 1300) may include the first UE or one of the one or more additional UEs.

[0146] 14 is a flow diagram of a method 1400 of positioning using SL communication in a first UE according to one embodiment. Here, the first UE may comprise an initiating or coordinating UE as described in the embodiments herein. The functions illustrated in the blocks of method 1400 may be performed by software and / or hardware components of the UE, such as those illustrated in FIG. 16 described below. Any direct wireless SL communication used to perform one or more of the functions of method 1400 may use user plane signaling and / or control plane signaling. Furthermore, one or more of the functions of method 1400 may be performed in an SLPP positioning session.

[0147] In block 1410, the function includes transmitting one or more capability request messages from the first UE to one or more additional UEs via direct wireless SL communication, each capability request message including a request for one or more capabilities to support SL-PRS configuration and SL-PRS measurements. As described above with reference to FIGS. 8-12, the capability request message(s) may be transmitted after device and service discovery and / or after initiation of an SLPP positioning session. Accordingly, some embodiments of method 1400 may include performing a discovery process by the first UE to identify the one or more additional UEs before transmitting the one or more capability request messages. As described above, the capability request messages may be communicated to each of the one or more additional UEs via unicast or, if the one or more additional UEs include multiple additional UEs, may be multicast (or broadcast) to the multiple additional UEs.

[0148] The means for performing the functions in block 1410 may comprise a bus 1605, a processor(s) 1610, a DSP 1620, a wireless communication interface 1630 (e.g., a transceiver), a memory 1660, and / or other components of the UE 1600, as shown in FIG. 16 described below.

[0149] In block 1420, the function includes receiving, at the first UE via direct wireless SL communication from one or more additional UEs, one or more capability provision messages in which the one or more additional UEs respond to the one or more capability request messages. Again, this capability exchange may be part of an SLPP positioning session, such as those shown in FIGS. 8-12, as previously described.

[0150] The means for performing the functions in block 1420 may comprise a bus 1605, a processor(s) 1610, a DSP 1620, a wireless communication interface 1630 (e.g., a transceiver), a memory 1660, and / or other components of the UE 1600, as shown in FIG. 16 described below.

[0151] In block 1430, the function includes obtaining an SL-PRS configuration for each of the one or more additional UEs based at least in part on the one or more capability provision messages. As described above in embodiments herein, obtaining an SL-PRS configuration for each of the one or more additional UEs may include either (i) determining, with the first UE, an SL-PRS configuration for each of the one or more additional UEs, or (ii) sending data from the one or more capability provision messages from the first UE to a location server (e.g., the LMF) and receiving, at the first UE from the location server, an SL-PRS configuration for each of the one or more additional UEs.

[0152] The means for performing the functions in block 1430 may comprise a bus 1605, a processor(s) 1610, a DSP 1620, a wireless communication interface 1630 (e.g., a transceiver), a memory 1660, and / or other components of the UE 1600, as shown in FIG. 16 described below.

[0153] In block 1440, the function includes transmitting one or more Provide Assistance Data messages from the first UE to one or more additional UEs via direct wireless SL communication, the one or more Provide Assistance Data messages including an SL-PRS configuration for each of the one or more additional UEs. As described elsewhere herein, according to some embodiments of method 1400, prior to transmitting the one or more capability request messages, the method may include exchanging multiple announcement messages between the first UE and a location server (e.g., an LMF), and transmitting the one or more capability request messages is responsive to exchanging the multiple announcement messages. In such embodiments, exchanging the multiple announcement messages may include receiving a capability request message by the first UE from the location server. Additionally or alternatively, exchanging the multiple announcement messages may include receiving a location request by the first UE from the location server. In such embodiments, the location request may be included in a supplementary service request message.

[0154] The means for performing the functions in block 1440 may comprise a bus 1605, a processor(s) 1610, a DSP 1620, a wireless communication interface 1630 (e.g., a transceiver), a memory 1660, and / or other components of the UE 1600, as shown in FIG. 16 described below.

[0155] Some embodiments of method 1400 may further include one or more additional features as described in other embodiments detailed herein. For example, some embodiments of method 1400 may further include transmitting one or more location information request messages from the first UE to one or more additional UEs via direct wireless SL communication, each location information request message including a request for positioning measurement data, and receiving, at the first UE from the one or more additional UEs via direct wireless SL communication, one or more provide location information messages in which the one or more additional UEs provide the positioning measurement data. In such embodiments, method 1400 may further include performing, with the first UE, SL-PRS measurements in accordance with an SL-PRS configuration for each of the one or more additional UEs. Additionally or alternatively, method 1400 may further include performing a position calculation and obtaining location results (e.g., relative locations, directions, and / or distances) for the first UE and one or more additional UEs based, at least in part, on the positioning measurement data of the one or more location information providing messages. In such an embodiment, method 1400 may further include transmitting one or more additional location information providing messages including the location results from the first UE to the one or more additional UEs via direct wireless SL communication. Additionally or alternatively, obtaining the position calculation may include either (i) determining the position calculation with the first UE, or (ii) transmitting positioning measurement data from the first UE to a location server (e.g., LMF) and receiving the position calculation location results at the first UE from the location server. In some embodiments, the method 1400 may further include transmitting, from the first UE to a location server (e.g., an LMF), a location information providing message including either (i) the positioning measurement data or (ii) the position calculation location result determined by the first UE.

[0156] Additional or alternative features may be included in method 1400. For example, according to some embodiments, sending one or more capability request messages, receiving one or more capability provision messages, obtaining an SL-PRS configuration for each of the one or more additional UEs, and sending one or more provide assistance data messages occurs within an SLPP positioning session. Additionally or alternatively, the one or more additional UEs includes multiple UEs. In such embodiments, the one or more capability request messages, the one or more provide capability messages, or the one or more provide assistance data messages, or any combination thereof, comprise multicast or broadcast messages.

[0157] FIG. 15 is a flow diagram of a method 1500 for enabling a first UE to coordinate positioning using SL communications, according to one embodiment. Some or all of the functions illustrated in method 1500 may be performed by a second UE (e.g., UEs A, C, and / or D in FIGS. 8-12) communicating with the first UE (e.g., an initiating or coordinating UE, such as UE B in FIGS. 8-12). The functions illustrated in the blocks of method 1500 may be performed by software and / or hardware components of the UE, such as those illustrated in FIG. 16, described below. Again, any direct wireless SL communications used to perform one or more of the functions of method 1500 may use user plane signaling and / or control plane signaling. Furthermore, one or more of the functions of method 1500 may be performed in an SLPP positioning session.

[0158] In block 1510, the functions include receiving a capability request message at a second UE via direct wireless SL communication from a first UE, the second UE being one of one or more additional UEs other than the first UE used for positioning using SL communication, the capability request message including a request for one or more capabilities to support SL-PRS configuration and SL-PRS measurements. Means for performing the functions in block 1510 may comprise a bus 1605, a processor(s) 1610, a DSP 1620, a wireless communication interface 1630 (e.g., a transceiver), a memory 1660, and / or other components of the UE 1600, as shown in FIG. 16 described below.

[0159] The functions in block 1520 include sending a capability provision message from the second UE to the first UE via direct wireless SL communication in response to the capability request message. As described in previous embodiments, the capability provision message may include capabilities related to supporting SL positioning, transmitting and / or measuring SL-PRS, etc. Means for performing the functions in block 1520 may comprise a bus 1605, a processor(s) 1610, a DSP 1620, a wireless communication interface 1630 (e.g., a transceiver), a memory 1660, and / or other components of the UE 1600, as shown in FIG. 16 described below.

[0160] At block 1530, receiving, at the second UE from the first UE via direct wireless SL communication, a provide assistance data message including an SL-PRS configuration for the second UE, the SL-PRS configuration based at least in part on the provide capability message. Means for performing the functions at block 1530 may comprise a bus 1605, a processor(s) 1610, a DSP 1620, a wireless communication interface 1630 (e.g., a transceiver), a memory 1660, and / or other components of the UE 1600, as shown in FIG. 16 described below.

[0161] Embodiments of method 1500 may include one or more additional functions depending on desired functionality. For example, some embodiments of method 1500 may include receiving a location information request message at a second UE from a first UE via direct wireless SL communication; performing one or more measurements of an SL-PRS according to an SL-PRS configuration for the second UE; and transmitting a location information provide message from the second UE to the first UE via direct wireless SL communication, the content of the location information provide message being based on the one or more measurements. In such embodiments, the location information provide message may include a multicast message or a broadcast message. Additionally or alternatively, method 1500 may include performing a position calculation based on the one or more measurements and obtaining location results (e.g., relative location, direction, and / or distance) for the first UE, the second UE, and / or other of the one or more additional UEs, the location information provide message including the location results. The location information provide message may include data indicative of the one or more measurements.

[0162] 16 is a block diagram of one embodiment of a UE 1600 that may be utilized as described above herein (e.g., in connection with the preceding figures with respect to UEs, mobile devices, etc.). It should be noted that FIG. 16 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 the UE described herein may be performed by one or more of the hardware and / or software components illustrated in FIG. 16.

[0163] 16. UE 1600 is shown comprising hardware elements that may be electrically coupled (or may communicate in other ways, as needed) via a bus 1605. The hardware elements may include processor(s) 1610, which may include, but are not limited to, one or more general-purpose processors (e.g., application processors), one or more special-purpose processors (such as DSP chips, graphics acceleration processors, application-specific integrated circuits (ASICs)), and / or other processing structures or means. Processor(s) 1610 may include one or more processing units that may be housed in a single integrated circuit (IC) or multiple ICs. As shown in FIG. 16, some embodiments may have a separate DSP 1620 depending on desired functionality. Location determination and / or other decisions based on wireless communication may be performed in processor(s) 1610 and / or in wireless communication interface 1630 (described below). The UE 1600 may also include one or more input devices 1670, 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 1615, which may include, but are not limited to, one or more displays (e.g., touchscreens), light-emitting diodes (LEDs), speakers, etc.

[0164] The UE 1600 may also include a wireless communication interface 1630, 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 1600 to communicate with other devices as described in the above embodiments. The wireless communication interface 1630 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 antenna(s) 1632 that transmit and / or receive wireless signals 1634. According to some embodiments, the wireless communication antenna(s) 1632 may include multiple individual antennas, an antenna array, or any combination thereof. The antenna(s) 1632 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 1630 may include such circuitry.

[0165] Depending on the desired functionality, the wireless communication interface 1630 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 1600 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.

[0166] The UE 1600 may further include sensor(s) 1640. The sensor(s) 1640 may include, but are not limited to, one or more inertial sensors and / or other sensors (e.g., accelerometer(s), gyroscope(s), camera(s), magnetometer(s), altimeter(s), microphone(s), proximity sensor(s), light sensor(s), barometer(s), etc.), some of which may be used to obtain location-related measurements and / or other information.

[0167] An embodiment of the UE 1600 may also include a Global Navigation Satellite System (GNSS) receiver 1680 capable of receiving signals 1684 from one or more GNSS satellites using an antenna 1682 (which may be the same as the antenna 1632). Positioning based on GNSS signal measurements may be utilized to complement and / or incorporate the techniques described herein. The GNSS receiver 1680 may use conventional techniques to extract a position of the UE 1600 from GNSS satellites of a GNSS system such as Global Positioning System (GPS), Galileo, GLONASS, the Quasi-Zenith Satellite System (QZSS) over Japan, the IRNSS over India, or the Beidou Navigation Satellite System (BDS) over China. The GNSS receiver 1680 can also 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 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).

[0168] It should be noted that while the GNSS receiver 1680 is illustrated in FIG. 16 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). In some embodiments, the GNSS receiver may therefore comprise a measurement engine executed (as software) by one or more processors, such as the processor(s) 1610, the DSP 1620, and / or a processor within the wireless communication interface 1630 (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(s) 1610 or the DSP 1620.

[0169] The UE 1600 may further include and / or communicate with memory 1660. The memory 1660 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.

[0170] The memory 1660 of the UE 1600 may also comprise software elements (not shown in FIG. 16 ) 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 method(s) discussed above may be implemented as code and / or instructions in the memory 1660 that are executable by the UE 1600 (and / or the processor(s) 1610 or DSP 1620 within the UE 1600). 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.

[0171] FIG. 17 is a block diagram of one embodiment of a computer system 1700 that may be used in whole or in part to provide the functionality of one or more components and / or devices as described in the embodiments herein (including location servers such as LMFs). This may include, for example, a computer server, a personal computer, a personal electronic device, etc. Note that FIG. 17 is intended only to provide a generalized illustration of various components, any or all of which may be utilized as desired. Thus, FIG. 17 broadly illustrates how individual system elements may be implemented in a relatively separate or relatively more integrated fashion. Additionally, note that the components illustrated in FIG. 17 may be localized in a single device and / or distributed among various networked devices that may be located in different geographic locations.

[0172] Computer system 1700 is shown including hardware elements that may be electrically coupled (or may communicate as needed) via a bus 1705. The hardware elements may include processor(s) 1710, which may include, but are not limited to, one or more general-purpose processors, one or more special-purpose processors (such as digital signal processing chips, graphics acceleration processors, etc.), and / or other processing structures that may be configured to perform one or more of the methods described herein. Computer system 1700 may also include one or more input devices 1715, which may include, but are not limited to, a mouse, keyboard, camera, microphone, etc., and one or more output devices 1720, which may include, but are not limited to, a display device, printer, etc.

[0173] Computer system 1700 may further include (and / or communicate with) one or more non-transitory storage devices 1725, which may comprise, but are not limited to, local and / or network-accessible storage, and / or may comprise, but are not limited to, 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. Such data stores may include database(s) and / or other data structures used to store and manage messages and / or other information to be sent to one or more devices via the hub, as described herein.

[0174] The computer system 1700 may also include a communications subsystem 1730, which may include wireless communications technologies managed and controlled by a wireless communications interface 1733, as well as wired technologies (such as Ethernet, coaxial communications, and universal serial bus (USB)). The wireless communications interface 1733 may include one or more wireless transceivers that may transmit and receive wireless signals 1755 (e.g., signals according to 5G NR or LTE) via wireless antenna(s) 1750. Thus, the communications subsystem 1730 may comprise a modem, a network card (wireless or wired), an infrared communications device, a wireless communications device, and / or a chipset, etc., which may enable the computer system 1700 to communicate in any or all of the communications networks described herein to any device on the respective network, including user equipment (UE), base stations, and / or other transmission / reception points (TRPs), and / or any other electronic device described herein. Thus, the communications subsystem 1730 may be used to receive and transmit data as described in the embodiments herein.

[0175] In many embodiments, computer system 1700 will further include working memory 1735, which may include a RAM device or a ROM device, as described above. Software elements shown as residing in working memory 1735 may include other code, such as an operating system 1740, device drivers, executable libraries, and / or one or more applications 1745, which may include computer programs provided by various embodiments and / or may be designed to implement methods and / or configure systems provided by other embodiments, as described herein. By way of example only, one or more procedures described with respect to the method(s) described above may be implemented as code and / or instructions executable by a computer (and / or a processor within a computer), and in one aspect, 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 method.

[0176] A set of these instructions and / or code may be stored on a non-transitory computer-readable storage medium, such as storage device(s) 1725 described above. In some cases, the storage medium may be incorporated within a computer system, such as computer system 1700. In other embodiments, the storage medium may be separate from the computer system (e.g., a removable medium such as an optical disk) and / or provided in an installation package, such that the storage medium may be used to program, configure, and / or adapt a general-purpose computer with the instructions / code stored thereon. These instructions may be in the form of executable code that can be executed by computer system 1700 and / or may be in the form of source and / or installable code that, when compiled and / or installed on computer system 1700 (e.g., using any of a variety of publicly available compilers, installation programs, compression / decompression utilities, etc.), is then in the form of executable code.

[0177] One limitation of the sidelink (PC5) user plane with broadcast and groupcast is that the automatic repeat request (ARQ) procedure may not be supported at the radio link control (RLC) level, which can lead to loss of SLPP messages, for example, when the distance between the transmitting and receiving UEs increases beyond some threshold (e.g., 1 kilometer) or if some obstacle (e.g., a building, vehicle, tree, or hill) between the transmitting and receiving UEs blocks the transmission. This can also occur in either PC5 user plane signaling (PC5-U) or PC5 control plane signaling (PC5-S) if RLC is not used in acknowledged mode (with ARQ) or if ARQ is used but lost RLC-level packets cannot be successfully retransmitted. Such potential loss of messages at the transport level is unprecedented, as LPP message loss can also occur in Uu operation when LPP messages are not successfully forwarded by the MME or AMF, resulting in LPP messages being lost when the LPP itself includes acknowledgement and retransmission capabilities. According to some embodiments, such acknowledgment and retransmission capabilities are supported by SLPP (for either PC5-U or PC5-S SLPP message transport) and can be used, for example, when a small number of UEs are communicating. In this case, if the original SLPP message is sent using broadcast or groupcast, the SLPP acknowledgment and possibly retransmissions can be sent using unicast, possibly with ARQ support at the RLC level for higher reliability. An example of such acknowledgment and retransmission capabilities for SLPP messages is shown in FIG. 18.

[0178] Figure 18 is a signal flow diagram 1800 illustrating an example of acknowledgment and retransmission capabilities for SLPP messages that may be utilized in accordance with some embodiments. In Figure 18, there are four UEs (UEs A, B, C, and D) in a scenario similar to Figures 8 and 9, with UE B being the initiator UE that sends messages to UEs A, C, and D. However, as with the other figures, Figure 18 is provided as a non-limiting example. Other scenarios may have a greater or lesser number of UEs and may implement variations on the process shown in Figure 18.

[0179] The process may begin with an operation indicated by arrow 1810 in which UE B transmits an SLPP message using unicast, broadcast, or groupcast (also called multicast). If unicast is used, UE B transmits the SLPP message separately to UEs A, C, and D, resulting in three separate transmissions of the SLPP message. If broadcast or groupcast is used, UE B transmits the SLPP message only once to UEs A, C, and D, resulting in only one transmission of the SLPP message. In this example, the SLPP message may include any SLPP messages (e.g., as described herein) transmitted by UE B to multiple other UEs to enable SLPP positioning. UE B may recognize UE B (UEs A, C, and D) for which the SLPP message is intended and may therefore know from which UEs it can expect an acknowledgment. However, as indicated by block 1812, UE A does not receive the SLPP message transmitted by UE B. Meanwhile, UEs C and D receive the SLPP message, as indicated by blocks 1814 and 1816, respectively. As a result, both UE D and UE C may provide an acknowledgement to UE B, as shown in blocks 1820 and 1830, respectively. According to some embodiments, the acknowledgement may be sent using unicast messaging, possibly with error correction (e.g., using automatic repeat request (ARQ) at the radio link control (RLC) protocol level), which can help ensure that UE B receives the acknowledgement (e.g., taking into account retransmission procedures for unicast messaging).

[0180] The remaining operations in flow diagram 1800 illustrate how retransmissions may occur, according to some embodiments. At block 1850, UE B determines that it has not received an acknowledgment (ACK) from UE A (e.g., after a timeout period). Based on this, UE B may retransmit the SLPP message transmitted at arrow 1810. In some embodiments, UE B may retransmit using broadcast or groupcast (e.g., if multiple UEs failed to provide an acknowledgment), although unicast retransmission, possibly with error correction (e.g., using ARQ at the RLC protocol level), can help ensure that the SLPP message is received by UE A. Thus, as shown, UE B performs a retransmission of the SLPP message, as indicated by arrow 1860, and UE A provides an acknowledgment of receiving the SLPP message, as indicated by arrow 1870. More broadly, in a scenario in which one or more UEs are unable to provide an acknowledgment of an SLPP message by the sender, the sender may send either a unicast retransmission of the SLPP message to each of the one or more UEs, or a broadcast or groupcast retransmission of the SLPP message to all of the one or more UEs.

[0181] For large groups of UEs, such as V2X, acknowledgments and retransmissions may not be very efficient. In these cases, the SLPP procedure can be designed to have redundancy and (e.g., optionally) tolerance to transport failures. With redundancy, a UE can send an SLPP request or information message containing SLPP information to a group of UEs, and each UE in the group of UEs then responds, e.g., to acknowledge receipt of the information or to acknowledge that it has performed or can later perform some requested action (e.g., such sidelink reference signal transmission and / or measurement). If each response also carries the original information from the SLPP request message and is returned using groupcast or broadcast, any UE that did not receive the SLPP request message but receives at least one response message can infer and reconstruct the original SLPP request, thereby overcoming the loss of the original SLPP message.

[0182] Figure 19 is a signal flow diagram 1900 illustrating an example of how an SLPP procedure may include SLPP message redundancy that may be utilized in accordance with some embodiments. The scenario of Figure 19 again uses a (non-limiting) scenario with four UEs (UEs A, B, C, and D) where UE B is the initiator UE sending messages to UEs A, C, and D. Other scenarios may have a greater or lesser number of UEs and may implement variations on the process shown in Figure 19.

[0183] The process may begin in a manner similar to the example of FIG. 18, with UE B transmitting an SLPP message using broadcast or groupcast, as indicated by arrow 1910. Again, UE A does not receive the SLPP message from UE B, as indicated by block 1912, while both UEs C and D receive the SLPP message, as indicated by blocks 1914 and 1916. However, in contrast to FIG. 18, both UE C and UE D provide SLPP responses (e.g., acknowledgments or other messages) using broadcast or groupcast. Each SLPP response may include information that overlaps with (i.e., is included in) the SLPP message (e.g., information for transmitting and / or measuring sidelink reference signals) that may enable UE A to reconstruct the SLPP message transmitted by UE B. Thus, as further shown in FIG. 19, UE A receives SLPP responses from UE C and / or UE D, as indicated by block 1940, and further reconstructs the SLPP message from UE B based on the SLPP response, as indicated by block 1950. With the reconstructed SLPP message, UE A can then send a SLPP response via broadcast / groupcast (as can UEs C and D), as indicated by arrow 1960.

[0184] As mentioned above, some embodiments may utilize such redundancy in conjunction with transport failure tolerance. With respect to transport failure tolerance, a sender of an SLPP request message to a group of UEs (e.g., using unicast, broadcast, or groupcast, and either PC5-U or PC5-S) may expect that not all UEs will receive the request message (or successfully respond), and therefore, when an SLPP response message is not received from all UEs, the sender may take appropriate action, such as retransmitting the SLPP request message later or not expecting UEs for which no response was received to take any requested action. Supporting acknowledgments with retransmissions, redundancy, and / or transport failure tolerance may add some signaling and procedural overhead that would not be required if all signaling were based on reliable unicast (e.g., using ARQ). However, the higher efficiency and lower latency (e.g., for V2X) may more than compensate for this otherwise. It should also be noted that if preferred (e.g., for a pair of UEs), the sidelink / PC5 user plane (PC5-U) can still be used with unicast motes with extra ARQ support transport reliability.

[0185] FIG. 20 is a signal flow diagram 2000 illustrating an exemplary hybrid positioning method that utilizes SL positioning in conjunction with Uu positioning (e.g., one or more base stations) to provide hybrid (or "joint") Uu and SL positioning for a group of UEs (UEs A, B, C, and D in this example). The basic SLPP transaction types (Capability Transfer, Assistance Data Transfer, Location Information Transfer) suitable for supporting in-coverage, partial coverage, and out-of-coverage sidelink positioning and ranging scenarios can also be applied to support joint sidelink-Uu positioning. This can be easily achieved by jointly executing the SLPP, LPP, and NRPPa procedures for the desired positioning method as shown in FIG. 20. In Uu positioning, the LPP and / or NRPPa may be used for UE positioning operations for UE A (e.g., for multi-RTT), but Uu positioning using the LPP and / or NRPPa can also, or instead, be used for any of UE B, UE C, and UE D if the LS in FIG. 20 has access to each of these UEs. In SL positioning, UE A in Figure 20 is the UE with which the LS in Figure 20 interacts, similar to the interaction between the LS and UE B described for example with respect to Figures 10-12. In joint Uu and SL positioning, any combination of LPP, SLPP, and NRPPa may be used depending on the desired positioning method(s) (UL, DL, SL positioning).

[0186] In some implementations, to enable supporting a positioning procedure (e.g., using SLPP and / or LPP) more accurately, more reliably, more efficiently, more securely, or with some other benefit in performance or results, it may be useful for a first UE to inform another UE, a group of UEs, or a location server (e.g., LMF) of some temporary or semi-permanent status or state of the first UE. Examples of temporary or semi-permanent status or state of a UE may include any of the following: (a) use by a UE of another relay UE to transmit signaling (e.g., SLPP or LPP messages and / or other messages) to another entity such as another UE, the network, or an LMF (e.g., when the relay UE forwards signaling from the UE to another entity and from another entity to the UE); (b) Use by a satellite (or satellite access) UE to transmit signaling (e.g., SLPP or LPP messages and / or other messages) to another entity, such as another UE, a network, or an LMF; (c) use by the UE of the WiFi access point to send signaling (e.g., SLPP or LPP messages and / or other messages) to another entity, such as another UE, a network, or an LMF; (d) high levels of interference or any other radio conditions at the UE that may interfere with signaling, location measurements, and / or reference signal transmission; and (e) No access to the network by the UE (e.g., the UE is out of network coverage or does not have a subscription to access the network).

[0187] In some embodiments, where a bit is set to (e.g.,) a binary 1 to indicate the presence of a particular status or condition and set to (e.g.,) a binary 0 to indicate the absence of a particular status or condition, one or more status items or conditions may be indicated using a bit string. An indication (e.g., a bit string) of the one or more status items or conditions may then be included in an SLPP or LPP message transmitted by the UE, such as an SLPP or LPP Capability Provision message, an SLPP or LPP Assistance Data Request message, and / or an SLPP or LPP Location Information Request message. For example, any of the SLPP and LPP messages described with respect to Figures 8-12 may include an additional status item or condition (e.g., represented by a bit string) that indicates a particular temporary or semi-permanent status or condition of the transmitting UE with respect to that SLPP or LPP message. If any of the status items or states are present when the UE sends an LPP or SLPP message, or if any of the status items or states have changed since the LPP or SLPP message was sent to one or more recipient entities that included the status item or state, the UE may initially include additional status items or states in any LPP or SLPP message sent to one or more recipient entities. The one or more recipient entities may take appropriate action based on the received status items or states. For example, if the status item or state indicates that the UE is using a satellite or a WiFi AP to send signaling to another entity, the other entity may invoke a positioning method appropriate for such signaling (e.g., GPS or GNSS for satellite access or WiFi positioning for WiFi access). If the status item or state indicates that the UE is using a relay UE to send signaling to another entity, the other entity may not invoke a positioning method that relies on a UE having direct access to the network or other entity.

[0188] 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.

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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 modify the application of 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.

[0194] In view of this description, embodiments may include different combinations of features. Example implementations are described in the following numbered clauses.

[0195] Clause 1. A method of positioning a plurality of user equipments (UEs) using sidelink (SL) communications, the method being performed by one UE of the plurality of UEs, the method comprising: exchanging a plurality of SL Positioning Protocol (SLPP) messages, the plurality of SLPP messages being exchanged via direct wireless SL communications, at least one message of the plurality of SLPP messages including a capability request message by a first UE of the plurality of UEs requesting capability to support positioning using SL communications from one or more additional UEs of the plurality of UEs; at least one message of the plurality of SLPP messages including a capability offer message indicating capability for at least one of the one or more additional UEs to support positioning using SL communications; and at least one message of the plurality of SLPP messages including a capability offer message indicating capability for at least one of the one or more additional UEs to support positioning using SL communications. E, the data including a Provide Assistance Data message that assists the one or more additional UEs in performing positioning using SL communication, at least one message of the plurality of SLPP messages including a Location Information Request message by the first UE requesting location measurements for positioning using SL communication from one or more additional UEs of the plurality of UEs, and at least one message of the plurality of SLPP messages including a Provide Location Information message by at least one of the one or more additional UEs providing location measurements for positioning using SL communication; and performing positioning based at least in part on the plurality of positioning messages.

[0196] Clause 2. The method of clause 1, wherein the direct wireless SL communication uses user plane signaling or control plane signaling.

[0197] Clause 3. The method of any one of clauses 1 to 2, further comprising, before exchanging a plurality of SLPP messages, engaging in a discovery process to determine one or more of the other UEs that should participate in the positioning.

[0198] Clause 4. The method of any one of clauses 1 to 3, wherein the exchange of multiple SLPP messages and the execution of positioning are performed within an SLPP positioning session.

[0199] Clause 5. The method of any one of clauses 1 to 4, wherein the provide assistance data message is sent from the first UE to one or more additional UEs of the plurality of UEs.

[0200] Clause 6. The method of clause 5, wherein the content of the assistance data provision is based at least in part on configuration information received by the first UE from the server.

[0201] Clause 7. The method of clause 6, wherein the configuration information received by the first UE from the server is based at least in part on capability information provided by the first UE to the server, and the capability information is based at least in part on a capability provision message.

[0202] Clause 8. A method according to any one of clauses 5 to 7, wherein a plurality of pre-announced SLPP messages are exchanged between the first UE and the server before exchanging a plurality of SLPP messages with other UEs among the plurality of UEs, and the exchange of a plurality of SLPP messages with other UEs among the plurality of UEs is based on the exchange of a plurality of pre-announced SLPP messages.

[0203] Clause 9. The method of clause 8, wherein the plurality of advance notice SLPP messages includes a capability request message from the server.

[0204] Clause 10. The method of any one of clauses 8 to 9, wherein the plurality of announced SLPP messages includes a location information request message from the server.

[0205] Clause 11. The method according to clause 10, wherein the location information request message is included in a supplementary service request message.

[0206] Clause 12. The method of any one of clauses 1 to 11, wherein the plurality of SLPP messages include a unicast message sent to one UE of the plurality of UEs, a multicast message sent by one UE of the plurality of UEs to all other UEs of the plurality of UEs, a broadcast message sent to a UE of the plurality of UEs and to a UE that is not in the plurality of UEs, or any combination thereof.

[0207] Clause 13. The method of any one of clauses 1 to 12, wherein the UE comprises a first UE.

[0208] Clause 14. The method of any one of clauses 1 to 12, wherein the UE comprises one UE of one or more additional UEs.

[0209] Clause 15. The method of any one of clauses 1 to 12, wherein at least one message of the plurality of SLPP messages includes an SLPP message sent from a first UE to two or more additional UEs of the plurality of UEs using unicast, groupcast, or broadcast messaging without lower layer error correction, and an acknowledgment to the SLPP message is received by the first UE, and an acknowledgment is sent from at least one of the two or more additional UEs using unicast messaging without lower layer error correction.

[0210] Clause 16. The method of clause 15, wherein the first UE determines whether an acknowledgment to the SLPP message was not received from a particular UE of the two or more additional UEs, and in response to determining that an acknowledgment to the SLPP message was not received from the particular UE, a retransmission of the SLPP message is sent from the first UE to the particular UE using unicast messaging without lower layer error correction.

[0211] Clause 17. A method according to any one of clauses 1 to 16, wherein at least one message of the plurality of SLPP messages comprises an SLPP message transmitted from a first UE to two or more additional UEs of the plurality of UEs using groupcast or broadcast messaging without lower layer error correction, the SLPP message having SLPP information for performing an SLPP procedure, and a response message transmitted from at least one of the two or more additional UEs is received from the first UE, the response message being transmitted using groupcast or broadcast messaging, and the response message including the SLPP information.

[0212] Clause 18. The method of clause 17, wherein a second UE of the two or more additional UEs sends a response message to the first UE in response to receiving the SLPP message sent from the first UE, and a third UE of the two or more additional UEs sends a second response message to the first UE in response to receiving the response message sent from the second UE, and the SLPP message sent from the first UE is not received by the third UE.

[0213] Clause 19. The method of any one of clauses 1 to 18, wherein at least one message of the plurality of SLPP messages includes an SLPP message transmitted from a first UE to two or more additional UEs of the plurality of UEs using unicast, groupcast, or broadcast messaging without lower layer error correction, the SLPP message is associated with performing an SLPP procedure, a set of one or more responses to the SLPP message is received by the first UE, a set of one or more responses to the SLPP message is received from each UE of a first portion of the two or more additional UEs, no response to the SLPP message is received from a second portion of the two or more additional UEs, and proceeding to perform the SLPP procedure based on the set of one or more responses to the SLPP message received from each UE of the first portion of the two or more additional UEs.

[0214] Clause 20. The method of clause 19, wherein the number of UEs in the first portion of the two or more additional UEs exceeds a minimum threshold number of UEs for performing an SLPP procedure.

[0215] Clause 21. A method of positioning using side link (SL) communication in a first user equipment (UE), the method comprising: transmitting one or more capability request messages from the first UE to one or more additional UEs via direct wireless SL communication, each capability request message comprising a request for an SL position reference signal (SL-PRS) configuration and one or more capabilities to support SL-PRS measurements; receiving at the first UE from the one or more additional UEs via direct wireless SL communication one or more capability provision messages in which the one or more additional UEs respond to the one or more capability request messages; obtaining an SL-PRS configuration for each of the one or more additional UEs based at least in part on the one or more capability provision messages; and transmitting one or more assistance data provision messages from the first UE to the one or more additional UEs via direct wireless SL communication, the SL-PRS configuration for each of the one or more additional UEs.

[0216] Clause 22. The method of clause 21, further comprising: sending one or more location information request messages from the first UE via direct wireless SL communication to one or more additional UEs, each location information request message including a request for positioning measurement data; and receiving at the first UE via direct wireless SL communication from the one or more additional UEs one or more location information provide messages in which the one or more additional UEs provide positioning measurement data.

[0217] Clause 23. The method of clause 22, further comprising: performing, with the first UE, SL-PRS measurements in accordance with an SL-PRS configuration for the first UE.

[0218] Clause 24. The method of any one of clauses 22-23, further comprising obtaining a position calculation based, at least in part, on positioning measurement data of one or more location information providing messages.

[0219] Clause 25. The method of clause 18, further comprising transmitting one or more additional location information providing messages comprising the position calculation from the first UE to one or more additional UEs via direct wireless SL communication.

[0220] Clause 26. The method of any one of clauses 24 to 25, wherein obtaining the position calculation includes either (i) determining the position calculation using the first UE, or (ii) sending positioning measurement data from the first UE to a server and receiving the position calculation at the first UE from the server.

[0221] Clause 27. The method of any one of clauses 22 to 26, further comprising sending from the first UE to the server a location information providing message including either (i) positioning measurement data, or (ii) a position calculation determined by the first UE.

[0222] Clause 28. A method according to any one of clauses 21 to 27, wherein obtaining an SL-PRS configuration for each of the one or more additional UEs includes either (i) determining an SL-PRS configuration for each of the one or more additional UEs using the first UE, or (ii) sending data from one or more capability provision messages from the first UE to a server and receiving an SL-PRS configuration for each of the one or more additional UEs from the server at the first UE.

[0223] Clause 29. A method according to any one of clauses 21 to 28, wherein the direct wireless SL communication uses user plane signalling or control plane signalling.

[0224] Clause 30. The method of any one of clauses 21 to 29, further comprising performing a discovery process with the first UE to identify one or more additional UEs before transmitting the one or more capability request messages.

[0225] Clause 31. The method of any one of clauses 21 to 30, wherein sending one or more capability request messages, receiving one or more capability provision messages, obtaining an SL-PRS configuration for each UE of the one or more additional UEs, and sending one or more assistance data provision messages are performed within an SL Positioning Protocol (SLPP) positioning session.

[0226] Clause 32. The method of any one of clauses 21 to 31, wherein the one or more additional UEs comprises a plurality of UEs.

[0227] Clause 33. The method of clause 32, wherein the one or more capability request messages, the one or more capability provision messages, or the one or more assistance data provision messages, or any combination thereof, comprise multicast or broadcast messages.

[0228] Clause 34. The method of any one of clauses 21 to 33, further comprising exchanging a plurality of advance notice messages between the first UE and the server before sending the one or more capability request messages, wherein sending the one or more capability request messages is in response to exchanging the plurality of advance notice messages.

[0229] Clause 35. The method of clause 34, wherein exchanging a plurality of announcement messages includes receiving, by the first UE, a capability request message from the server.

[0230] Clause 36. The method of any one of clauses 34-35, wherein exchanging a plurality of announcement messages includes receiving, by the first UE, a location request from the server.

[0231] Clause 37. The method of clause 36, wherein the location request is included in a supplementary service request message.

[0232] Clause 38. A method for enabling a first user equipment (UE) to coordinate positioning using sidelink (SL) communication, the method comprising: receiving a capability request message from the first UE via direct wireless SL communication to a second UE, the second UE being one of one or more additional UEs other than the first UE used for positioning using SL communication, the capability request message including a request for one or more capabilities to support SL position reference signals (SL-PRS) and SL-PRS measurements at the second UE; transmitting a capability provision message from the second UE via direct wireless SL communication to the first UE in response to the capability request message; and receiving an assistance data provision message from the first UE via direct wireless SL communication at the second UE including an SL-PRS configuration for the second UE, the SL-PRS configuration being based at least in part on the capability provision message.

[0233] Clause 39. The method of clause 38, further comprising receiving, at the second UE via direct wireless SL communication from the first UE, a location information request message, performing one or more measurements of the SL-PRS according to the SL-PRS configuration for the second UE, and sending, from the second UE via direct wireless SL communication, a location information provide message, wherein the content of the location information provide message is based on the one or more measurements.

[0234] Clause 40. The method of clause 39, wherein the location information providing message comprises a multicast message or a broadcast message.

[0235] Clause 41. The method of any one of clauses 39-40, further comprising determining a position calculation based on one or more measurements, wherein the location information providing message includes the position calculation.

[0236] Clause 42. The method of clauses 39 to 41, wherein the location information providing message includes data indicative of one or more measurement values.

[0237] Clause 43. A method according to any one of clauses 39 to 42, wherein the direct wireless SL communication uses user plane signalling or control plane signalling.

[0238] Clause 44. A user equipment (UE), comprising one or more transceivers, one or more memories, and one or more processors communicatively coupled to the one or more transceivers and the one or more memories, wherein the one or more processors exchange with other UEs of the plurality of UEs, via the one or more transceivers, a plurality of Sidelink (SL) Positioning Protocol (SLPP) messages, the plurality of SLPP messages being exchanged via direct wireless SL communications, at least one message of the plurality of SLPP messages including a capability request message from a first UE of the plurality of UEs requesting capability to support positioning using SL communications from one or more additional UEs of the plurality of UEs, and at least one message of the plurality of SLPP messages including a capability offer message indicating a capability for at least one of the one or more additional UEs to support positioning using SL communications, and one or more processors configured to: exchange a plurality of SLPP messages, wherein at least one message of the plurality of SLPP messages includes data for one or more additional UEs of the plurality of UEs, the data including a provide assistance data message that assists the one or more additional UEs in performing positioning using SL communication; at least one message of the plurality of SLPP messages includes a location information request message in which the first UE requests location measurements for positioning using SL communication from one or more additional UEs of the plurality of UEs; and perform positioning based, at least in part, on the plurality of positioning messages.

[0239] Clause 45. The UE of clause 44, wherein the one or more processors are configured to use user plane signaling or control plane signaling in direct wireless SL communication.

[0240] Clause 46. A UE as described in any one of clauses 44 to 45, wherein the one or more processors are further configured to engage in a discovery process to determine one or more of the other UEs that will participate in the positioning before exchanging multiple SLPP messages.

[0241] Clause 47. A UE according to any one of clauses 44 to 46, wherein the one or more processors are configured to exchange a plurality of SLPP messages and perform positioning within an SLPP positioning session.

[0242] Clause 48. A UE as described in any one of clauses 44 to 47, wherein the UE includes a first UE, and the one or more processors are configured to transmit an assistance data providing message to one or more additional UEs of the plurality of UEs.

[0243] Clause 49. The UE of clause 48, wherein the one or more processors are configured to base the content of the assistance data provision at least in part on configuration information received from the server via the one or more transceivers.

[0244] Clause 50. A UE as described in Clause 49, wherein the one or more processors are configured to exchange a plurality of advance SLPP messages with the server prior to exchanging a plurality of SLPP messages with other UEs among the plurality of UEs, and the exchange of a plurality of SLPP messages with other UEs among the plurality of UEs is based on the exchange of a plurality of advance SLPP messages.

[0245] Clause 51. The UE of clause 50, wherein the one or more processors are configured to receive a capability request message from the server to exchange a plurality of announced SLPP messages with the server.

[0246] Clause 52. A UE according to any one of clauses 50 to 51, wherein the one or more processors are configured to receive a location information request message from the server in order to exchange a plurality of pre-announced SLPP messages with the server.

[0247] Clause 53. The UE of clause 52, wherein the one or more processors are configured to receive a location information request message in a supplementary service request message.

[0248] Clause 54. A UE according to any one of clauses 44 to 53, wherein, to exchange a plurality of SLPP messages, the one or more processors are configured to receive a unicast message, a multicast message sent by one UE of the plurality of UEs to all other UEs of the plurality of UEs, a broadcast message sent to a UE of the plurality of UEs and to a UE that is not in the plurality of UEs, or any combination thereof.

[0249] Clause 55. The UE according to any one of clauses 44 to 54, wherein the UE comprises one UE of one or more additional UEs.

[0250] Clause 56. A UE as described in any one of clauses 44 to 54, wherein the UE includes a first UE, and to exchange a plurality of SLPP messages with a server, the one or more processors are configured to send at least one message including the SLPP message to two or more additional UEs of the plurality of UEs via one or more transceivers using unicast, groupcast, or broadcast messaging without lower layer error correction, and the one or more processors are configured to receive an acknowledgment to the SLPP message, the acknowledgment being sent from at least one of the two or more additional UEs using unicast messaging with lower layer error correction.

[0251] Clause 57. The UE of clause 56, wherein the one or more processors are further configured to: determine whether an acknowledgment to the SLPP message was not received from a particular UE of the two or more additional UEs; and, in response to determining that an acknowledgment to the SLPP message was not received from the particular UE, send a retransmission of the SLPP message to the particular UE using unicast messaging with lower layer error correction.

[0252] Clause 58. A UE as described in any one of clauses 44 to 54 or 56 to 57, wherein the UE includes a first UE, and to exchange a plurality of SLPP messages with a server, the one or more processors are configured to send at least one message including the SLPP message to two or more additional UEs of the plurality of UEs via one or more transceivers using groupcast or broadcast messaging without lower layer error correction, the SLPP message being associated with performing an SLPP procedure, the one or more processors are configured to receive a set of one or more responses to the SLPP message, the set of one or more responses to the SLPP message being received from each UE of a first portion of the two or more additional UEs, and no response to the SLPP message being received from a second portion of the two or more additional UEs, and the one or more processors proceed to perform the SLPP procedure based on the set of one or more responses to the SLPP message received from each UE of the first portion of the two or more additional UEs.

[0253] Clause 59. A first user equipment (UE) for positioning using sidelink (SL) communication, the first UE comprising one or more transceivers, one or more memories, and one or more processors communicatively coupled to the one or more transceivers and the one or more memories, the one or more processors transmitting one or more capability request messages via the one or more transceivers to one or more additional UEs via direct wireless SL communication, each capability request message including a request for one or more capabilities to support SL position reference signal (SL-PRS) configuration and SL-PRS measurements. and one or more processors configured to: receive, via direct wireless SL communication from the one or more additional UEs via the one or more transceivers, one or more capability provision messages in which the one or more additional UEs respond to the one or more capability request messages; obtain an SL-PRS configuration for each of the one or more additional UEs based at least in part on the one or more capability provision messages; and transmit, via direct wireless SL communication to the one or more additional UEs via the one or more transceivers, one or more assistance data provision messages including the SL-PRS configuration for each of the one or more additional UEs.

[0254] Clause 60. The first UE of Clause 59, wherein the one or more processors are further configured to: send one or more location information request messages via one or more transceivers to one or more additional UEs via direct wireless SL communication, each location information request message including a request for positioning measurement data; and receive one or more location information provide messages via one or more transceivers from the one or more additional UEs via direct wireless SL communication, in which the one or more additional UEs provide positioning measurement data.

[0255] Clause 61. The first UE of Clause 60, wherein the one or more processors are further configured to perform SL-PRS measurements in accordance with an SL-PRS configuration for the first UE via the one or more transceivers.

[0256] Clause 62. The first UE of any one of clauses 60-61, wherein the one or more processors are further configured to obtain a position calculation based at least in part on positioning measurement data of one or more location information providing messages.

[0257] Clause 63. The first UE of Clause 62, wherein the one or more processors are further configured to transmit one or more additional location information providing messages including the position calculation via the one or more transceivers to one or more additional UEs via direct wireless SL communication.

[0258] Clause 64. A first UE as described in any one of Clauses 62 to 63, wherein, to obtain a position calculation, the one or more processors are configured to: (i) obtain a position calculation; or (ii) transmit positioning measurement data to a server via one or more transceivers and receive a position calculation from the server via one or more transceivers.

[0259] Clause 65. A first UE as described in any one of clauses 60 to 64, wherein the one or more processors are further configured to transmit, via one or more transceivers to a server, a location information providing message including either (i) positioning measurement data, or (ii) a position calculation determined by the first UE.

[0260] Clause 66. The first UE of any one of clauses 59 to 65, wherein, to obtain an SL-PRS configuration for each of the one or more additional UEs, the one or more processors are further configured to: (i) determine an SL-PRS configuration for each of the one or more additional UEs; or (ii) send data from one or more capability provision messages to a server via one or more transceivers and receive an SL-PRS configuration for each of the one or more additional UEs from the server via the one or more transceivers.

[0261] Clause 67. The first UE of any one of clauses 59 to 66, wherein the one or more processors are configured to use user plane signaling or control plane signaling in direct wireless SL communication.

[0262] Clause 68. The first UE of any one of clauses 59 to 67, wherein the one or more processors are further configured to perform a discovery process to identify one or more additional UEs before transmitting one or more capability request messages.

[0263] Clause 69. The first UE of any one of clauses 59 to 68, wherein the one or more processors are configured to: send one or more capability request messages, receive one or more capability provision messages, obtain an SL-PRS configuration for each of the one or more additional UEs, and send one or more assistance data provision messages within an SL Positioning Protocol (SLPP) positioning session.

[0264] Clause 70. A first UE as described in any one of clauses 59 to 69, wherein the one or more processors are further configured to exchange a plurality of advance notice messages between the first UE and the server before sending the one or more capability request messages, and the one or more processors are configured to send the one or more capability request messages in response to the exchange of the plurality of advance notice messages.

[0265] Clause 71. The first UE of Clause 70, wherein the one or more processors are configured to receive a capability request message or a location request from the server via the one or more transceivers to exchange the plurality of advance notice messages.

[0266] Clause 72. The first UE of clause 71, wherein the one or more processors are configured to receive the location request in a supplementary service request message.

[0267] Clause 73. A second user equipment (UE) for enabling a first UE to coordinate positioning using side link (SL) communication, the second UE comprising one or more transceivers, one or more memories, and one or more processors communicatively coupled to the one or more transceivers and the one or more memories, the one or more processors transmitting SL position reference signals via the one or more transceivers from the first UE via direct wireless SL communication, the second UE being one of one or more additional UEs other than the first UE used for positioning using SL communication. and one or more processors configured to: receive a capability request message including a request for one or more capabilities to support (SL-PRS) configuration and SL-PRS measurements; transmit a capability provision message in response to the capability request message via the one or more transceivers to the first UE via direct wireless SL communication; and receive an assistance data provision message from the first UE via the one or more transceivers including an SL-PRS configuration for the second UE, wherein the SL-PRS configuration is based at least in part on the capability provision message.

[0268] Clause 74. The second UE of clause 73, wherein the one or more processors are further configured to receive a location information request message via the one or more transceivers from the first UE via direct wireless SL communication, perform one or more measurements of the SL-PRS according to the SL-PRS configuration for the second UE, and transmit a location information provide message via the one or more transceivers to the first UE via direct wireless SL communication, the content of the location information provide message being based on the one or more measurements.

[0269] Clause 75. The second UE of clause 74, wherein the one or more processors are further configured to determine a position calculation based on the one or more measurements, and wherein the location information provide message includes the position calculation.

[0270] Clause 76. The second UE of any one of clauses 74 to 75, wherein the one or more processors are further configured to include data indicative of the one or more measurements in the location information providing message.

[0271] Clause 77. The second UE of any one of clauses 73 to 76, wherein the one or more processors are configured to use user plane signaling or control plane signaling in the direct wireless SL communication.

[0272] Clause 78. A device comprising one or more transceivers, one or more memories, and one or more processors communicatively coupled to the one or more transceivers and the one or more memories, wherein the one or more processors are configured to perform the method of any one of clauses 1 to 43.

[0273] Clause 79. An apparatus having means for carrying out the method according to any one of clauses 1 to 43.

[0274] Clause 80. A non-transitory computer-readable medium storing instructions including code for performing the method of any one of clauses 1 to 43.

Claims

1. 1. A method for positioning a plurality of user equipments (UEs) using side link (SL) communications, the method being performed by one UE of the plurality of UEs, the method comprising: exchanging SL Positioning Protocol (SLPP) messages with other UEs of the plurality of UEs, wherein the SLPP messages are exchanged via direct wireless SL communication; At least one message of the plurality of SLPP messages includes a capability request message in which a first UE of the plurality of UEs requests capability to support positioning using SL communications from one or more additional UEs of the plurality of UEs; At least one message of the plurality of SLPP messages includes a capability provision message indicating a capability for at least one of the one or more additional UEs to support positioning using SL communication; at least one message of the plurality of SLPP messages includes a Provide Assistance Data message including data for the one or more additional UEs of the plurality of UEs, the data assisting the one or more additional UEs in performing positioning using SL communications; At least one message of the plurality of SLPP messages includes a Location Information Request message by which the first UE requests location measurements for positioning using SL communication from the one or more additional UEs of the plurality of UEs; exchanging a plurality of SLPP messages with other UEs of the plurality of UEs, wherein at least one of the plurality of SLPP messages includes a Provide Location Information message, where the at least one message of the plurality of SLPP messages provides the location measurement value for positioning using SL communication by at least one of the one or more additional UEs; performing the positioning based at least in part on the plurality of positioning messages; A method comprising:

2. The method of claim 1 , wherein the direct wireless SL communication uses user plane signaling or control plane signaling.

3. The method of claim 1 , further comprising, before exchanging the plurality of SLPP messages, engaging in a discovery process to determine one or more of the other UEs to participate in the positioning.

4. The method of claim 1 , wherein the exchange of the plurality of SLPP messages and the performance of the positioning occur within an SLPP positioning session.

5. The method of claim 1 , wherein the provide assistance data message is transmitted from the first UE to the one or more additional UEs of the plurality of UEs.

6. The method of claim 5 , wherein the content of the assistance data provision is based at least in part on configuration information received by the first UE from a server.

7. 7. The method of claim 6, wherein the configuration information received by the first UE from the server is based, at least in part, on capability information provided by the first UE to the server, the capability information being based, at least in part, on the capability provision message.

8. 7. The method of claim 6, wherein a plurality of announcement SLPP messages are exchanged between the first UE and the server before the exchange of the plurality of SLPP messages with the other UEs of the plurality of UEs, and the exchange of the plurality of SLPP messages with the other UEs of the plurality of UEs is based on the exchange of the plurality of announcement SLPP messages.

9. The method of claim 8 , wherein the plurality of announcement SLPP messages includes a capability request message from the server.

10. The method of claim 8 , wherein the plurality of announcement SLPP messages includes a location information request message from the server.

11. The method of claim 10 , wherein the location information request message is included in a supplementary service request message.

12. The plurality of SLPP messages include: a unicast message transmitted to one of the plurality of UEs; a multicast message transmitted by one UE of the plurality of UEs to all other UEs of the plurality of UEs; a broadcast message sent to UEs of the plurality of UEs and to UEs not in the plurality of UEs; or Any combination of them That is, The method of claim 1.

13. The method of claim 1 , wherein the UE comprises the first UE.

14. The method of claim 1 , wherein the UE comprises one of the one or more additional UEs.

15. at least one message of the plurality of SLPP messages comprises an SLPP message transmitted from the first UE to two or more additional UEs of the plurality of UEs using unicast, groupcast, or broadcast messaging without lower layer error correction; an acknowledgment to the SLPP message is received by the first UE, the acknowledgment being sent from at least one of the two or more additional UEs using unicast messaging without lower layer error correction; The method of claim 1.

16. the first UE determining whether an acknowledgment to the SLPP message was not received from a particular UE of the two or more additional UEs; In response to determining that an acknowledgment to the SLPP message was not received from the particular UE, a retransmission of the SLPP message is sent from the first UE to the particular UE using unicast messaging without lower layer error correction.

16. The method of claim 15.

17. at least one message of the plurality of SLPP messages comprises an SLPP message sent from the first UE to two or more additional UEs of the plurality of UEs using unicast, groupcast, or broadcast messaging without lower layer error correction, the SLPP message having SLPP information for performing an SLPP procedure; a response message sent from at least one of the two or more additional UEs is received from the first UE; the response message is transmitted using groupcast or broadcast messaging; The response message includes the SLPP information. The method of claim 1.

18. a second UE of the two or more additional UEs transmitting the response message to the first UE in response to receiving the SLPP message transmitted from the first UE; a third UE of the two or more additional UEs transmits a second response message to the first UE in response to receiving the response message transmitted from the second UE, and the SLPP message transmitted from the first UE is not received by the third UE; 18. The method of claim 17.

19. at least one message of the plurality of SLPP messages comprises an SLPP message transmitted from the first UE to two or more additional UEs of the plurality of UEs using groupcast or broadcast messaging without lower layer error correction, the SLPP message being related to performing an SLPP procedure; a set of one or more responses to the SLPP message is received by the first UE; the set of one or more responses to the SLPP message is received from each UE of a first portion of the two or more additional UEs; no response to the SLPP message is received from a second portion of the two or more additional UEs; proceeding to perform the SLPP procedure based on the set of one or more responses to the SLPP message received from each UE of the first portion of the two or more additional UEs. The method of claim 1.

20. 20. The method of claim 19, wherein a number of UEs in the first portion of the two or more additional UEs exceeds a minimum threshold number of UEs for performing the SLPP procedure.

21. 1. A method for positioning using side link (SL) communication in a first user equipment (UE), the method comprising: transmitting one or more capability request messages from the first UE to one or more additional UEs via direct wireless SL communication, each capability request message including a request for one or more capabilities to support SL-PRS configuration and SL-PRS measurements; receiving, at the first UE via the direct wireless SL communication from one or more additional UEs, one or more capability provision messages in response to the one or more capability request messages from the one or more additional UEs; obtaining an SL-PRS configuration for each UE of the one or more additional UEs based at least in part on the one or more capability provision messages; sending one or more Provide Assistance Data messages from the first UE to one or more additional UEs via the direct wireless SL communication, the Provide Assistance Data messages including the SL-PRS configuration for each UE of the one or more additional UEs; A method comprising:

22. sending one or more location information request messages from the first UE to one or more additional UEs via the direct wireless SL communication, each location information request message including a request for positioning measurement data; receiving, at the first UE from one or more additional UEs via the direct wireless SL communication, one or more provide location information messages in which the one or more additional UEs provide the positioning measurement data; 22. The method of claim 21 further comprising:

23. 23. The method of claim 22, further comprising: performing, with the first UE, SL-PRS measurements according to an SL-PRS configuration for the first UE.

24. 23. The method of claim 22, further comprising obtaining a position calculation based at least in part on positioning measurement data of the one or more location information providing messages.

25. 25. The method of claim 24, further comprising transmitting one or more additional location information providing messages including the position calculation from the first UE to one or more additional UEs via the direct wireless SL communication.

26. 25. The method of claim 24, wherein the obtaining the position calculation comprises either (i) determining the position calculation with the first UE, or (ii) sending the positioning measurement data from the first UE to a server and receiving the position calculation at the first UE from the server.

27. 23. The method of claim 22, further comprising: sending, from the first UE to a server, a Provide Location Information message including either (i) the positioning measurement data, or (ii) a position calculation determined by the first UE.

28. 22. The method of claim 21, wherein obtaining the SL-PRS configuration for each UE of the one or more additional UEs includes either (i) determining the SL-PRS configuration for each UE of the one or more additional UEs using the first UE, or (ii) transmitting the data from the one or more capability provision messages from the first UE to the server and receiving the SL-PRS configuration for each UE of the one or more additional UEs from the server at the first UE.

29. 22. The method of claim 21, wherein the direct wireless SL communication uses user plane signaling or control plane signaling.

30. 22. The method of claim 21, further comprising performing a discovery process with the first UE to identify the one or more additional UEs prior to transmitting the one or more capability request messages.

31. 22. The method of claim 21, wherein the transmitting the one or more capability request messages, the receiving the one or more capability provide messages, the obtaining the SL-PRS configuration for each UE of the one or more additional UEs, and the transmitting the one or more assistance data provide messages are performed within an SL Positioning Protocol (SLPP) positioning session.

32. The method of claim 21 , wherein the one or more additional UEs comprises a plurality of UEs.

33. 33. The method of claim 32, wherein the one or more capability request messages, the one or more capability provision messages, or the one or more assistance data provision messages, or any combination thereof, comprise multicast or broadcast messages.

34. 22. The method of claim 21, further comprising exchanging a plurality of announcement messages between the first UE and a server prior to the transmitting the one or more capability request messages, wherein transmitting the one or more capability request messages is in response to the exchanging the plurality of announcement messages.

35. 35. The method of claim 34, wherein the exchanging of the plurality of announcement messages includes receiving, by the first UE from the server, a capability request message.

36. 35. The method of claim 34, wherein the exchanging of the plurality of announcement messages includes receiving a location request by the first UE from the server.

37. 37. The method of claim 36, wherein the location request is included in a supplementary service request message.

38. 1. A method for enabling a first user equipment (UE) to coordinate positioning using side link (SL) communication, the method comprising: receiving, via direct wireless SL communication from the first UE, a capability request message including a request for one or more capabilities to support SL position reference signals (SL-PRS) and SL-PRS measurements at a second UE, the second UE being one of one or more additional UEs other than the first UE used for positioning using SL communication; sending a capability provision message from the second UE to the first UE via the direct wireless SL communication in response to the capability request message; receiving, at a second UE via direct wireless SL communication from the first UE, a provide assistance data message including an SL-PRS configuration for the second UE, wherein the SL-PRS configuration is based, at least in part, on the capability provision message.

39. receiving a location information request message at a second UE from the first UE via direct wireless SL communication; performing one or more measurements of a SL-PRS according to the SL-PRS configuration for the second UE; and 39. The method of claim 38, further comprising: sending a location information providing message from the second UE to the first UE via the direct wireless SL communication, wherein content of the location information providing message is based on the one or more measurements.

40. 40. The method of claim 39, wherein the location information providing message comprises a multicast message or a broadcast message.

41. 40. The method of claim 39, further comprising determining a position calculation based on the one or more measurements, wherein the location information providing message includes the position calculation.

42. 40. The method of claim 39, wherein the location information providing message includes data indicative of the one or more measurements.

43. 39. The method of claim 38, wherein the direct wireless SL communication uses user plane signaling or control plane signaling.

44. A user equipment (UE), one or more transceivers; one or more memories; one or more processors communicatively coupled to the one or more transceivers and the one or more memories, the one or more processors comprising: exchanging a plurality of Sidelink (SL) Positioning Protocol (SLPP) messages with other UEs of the plurality of UEs via the one or more transceivers, wherein the plurality of SLPP messages are exchanged via direct wireless SL communication; At least one message of the plurality of SLPP messages includes a capability request message in which a first UE of the plurality of UEs requests capability to support positioning using SL communications from one or more additional UEs of the plurality of UEs; At least one message of the plurality of SLPP messages includes a capability provision message indicating a capability for at least one of the one or more additional UEs to support positioning using SL communication; at least one message of the plurality of SLPP messages includes a Provide Assistance Data message including data for the one or more additional UEs of the plurality of UEs, the data assisting the one or more additional UEs in performing positioning using SL communications; At least one message of the plurality of SLPP messages includes a Location Information Request message by which the first UE requests location measurements for positioning using SL communication from the one or more additional UEs of the plurality of UEs; At least one message of the plurality of SLPP messages includes a Provide Location Information message, in which at least one of the one or more additional UEs provides the location measurements for positioning using SL communication. exchanging a plurality of SLPP messages; performing the positioning based at least in part on the plurality of positioning messages; and one or more processors configured to: A UE comprising:

45. 45. The UE of claim 44, wherein the one or more processors are configured to use user plane signaling or control plane signaling in the direct wireless SL communication.

46. 45. The UE of claim 44, wherein the one or more processors are further configured to, before exchanging the plurality of SLPP messages, engage in a discovery process to determine one or more of the other UEs that will participate in the positioning.

47. 45. The UE of claim 44, wherein the one or more processors are configured to exchange the plurality of SLPP messages and perform the positioning within an SLPP positioning session.

48. 45. The UE of claim 44, wherein the UE includes the first UE, and the one or more processors are configured to send the assistance data providing message to the one or more additional UEs of the plurality of UEs.

49. 49. The UE of claim 48, wherein the one or more processors are configured to base content of the assistance data provision, at least in part, on configuration information received from a server via the one or more transceivers.

50. 50. The UE of claim 49, wherein the one or more processors are configured to exchange a plurality of advance SLPP messages with the server before the exchange of the plurality of SLPP messages with the other UEs among the plurality of UEs, and the exchange of the plurality of SLPP messages with the other UEs among the plurality of UEs is based on the exchange of the plurality of advance SLPP messages.

51. 51. The UE of claim 50, wherein the one or more processors are configured to receive a capability request message from the server to exchange the plurality of announcement SLPP messages with the server.

52. 51. The UE of claim 50, wherein the one or more processors are configured to receive a location information request message from the server to exchange the plurality of announcement SLPP messages with the server.

53. 53. The UE of claim 52, wherein the one or more processors are configured to receive the location information request message in a supplementary service request message.

54. To exchange the plurality of SLPP messages, the one or more processors: unicast messages, a multicast message transmitted by one UE of the plurality of UEs to all other UEs of the plurality of UEs; a broadcast message sent to UEs of the plurality of UEs and to UEs not in the plurality of UEs; or Any combination of them That is, 45. The UE of claim 44.

55. 45. The UE of claim 44, wherein the UE comprises one of the one or more additional UEs.

56. the UE includes the first UE; to exchange the plurality of SLPP messages with a server, the one or more processors are configured to transmit at least one message including the SLPP message to two or more additional UEs of the plurality of UEs via the one or more transceivers using unicast, groupcast, or broadcast messaging without lower layer error correction; the one or more processors are configured to receive an acknowledgment to the SLPP message, the acknowledgment being sent from at least one of the two or more additional UEs using unicast messaging with lower layer error correction.

45. The UE of claim 44.

57. the one or more processors determining whether an acknowledgment to the SLPP message was not received from a particular UE of the two or more additional UEs; in response to determining that an acknowledgment to the SLPP message was not received from the particular UE, sending a retransmission of the SLPP message to the particular UE using unicast messaging with lower layer error correction.

57. The UE of claim 56, further configured to:

58. the UE includes the first UE; to exchange the plurality of SLPP messages with a server, the one or more processors are configured to transmit at least one message including an SLPP message to two or more additional UEs of the plurality of UEs via the one or more transceivers using groupcast or broadcast messaging without lower layer error correction, the SLPP message being related to performing an SLPP procedure; the one or more processors are configured to receive a set of one or more responses to the SLPP message; the set of one or more responses to the SLPP message is received from each UE of a first portion of the two or more additional UEs; no response to the SLPP message is received from a second portion of the two or more additional UEs; the one or more processors are configured to proceed to perform the SLPP procedure based on the set of one or more responses to the SLPP message received from each UE of the first portion of the two or more additional UEs.

45. The UE of claim 44.

59. a first user equipment (UE), one or more transceivers; one or more memories; one or more processors communicatively coupled to the one or more transceivers and the one or more memories, the one or more processors comprising: transmitting one or more capability request messages via the one or more transceivers via direct wireless sidelink (SL) communication to one or more additional UEs, each capability request message including a request for one or more capabilities to support SL-PRS configuration and SL-PRS measurements; receiving, via the one or more transceivers from one or more additional UEs via the direct wireless SL communication, one or more capability provision messages in response to the one or more capability request messages from the one or more additional UEs; obtaining an SL-PRS configuration for each UE of the one or more additional UEs based at least in part on the one or more capability provision messages; transmitting, via the one or more transceivers to one or more additional UEs via the direct wireless SL communication, one or more provide assistance data messages including the SL-PRS configuration for each UE of the one or more additional UEs; one or more processors configured to: a first UE comprising:

60. the one or more processors transmitting, via said one or more transceivers to one or more additional UEs via said direct wireless SL communication, one or more location information request messages, each location information request message including a request for positioning measurement data; receiving, via the direct wireless SL communication from one or more additional UEs via the one or more transceivers, one or more location information provide messages in which the one or more additional UEs provide the positioning measurement data; 60. The first UE of claim 59, further configured to:

61. The first UE of claim 60, wherein the one or more processors are further configured to perform SL-PRS measurements in accordance with an SL-PRS configuration for the first UE via the one or more transceivers.

62. 61. The first UE of claim 60, wherein the one or more processors are further configured to obtain a position calculation based at least in part on positioning measurement data of the one or more location information providing messages.

63. 63. The first UE of claim 62, wherein the one or more processors are further configured to transmit one or more additional location information providing messages including the position calculation via the one or more transceivers to one or more additional UEs via the direct wireless SL communication.

64. 63. The first UE of claim 62, wherein, to obtain the position calculation, the one or more processors are configured to: (i) obtain the position calculation; or (ii) transmit the positioning measurement data to a server via the one or more transceivers and receive the position calculation from the server via the one or more transceivers.

65. 61. The first UE of claim 60, wherein the one or more processors are further configured to transmit, via the one or more transceivers to a server, a location information provide message including either (i) the positioning measurement data, or (ii) a position calculation determined by the first UE.

66. 60. The first UE of claim 59, wherein, to obtain the SL-PRS configuration for each UE of the one or more additional UEs, the one or more processors are further configured to: (i) determine the SL-PRS configuration for each UE of the one or more additional UEs; or (ii) transmit the data from the one or more capability provision messages to a server via the one or more transceivers and receive the SL-PRS configuration for each UE of the one or more additional UEs from the server via the one or more transceivers.

67. 60. The first UE of claim 59, wherein the one or more processors are configured to use user plane signaling or control plane signaling in the direct wireless SL communication.

68. 60. The first UE of claim 59, wherein the one or more processors are further configured to perform a discovery process to identify the one or more additional UEs before transmitting the one or more capability request messages.

69. 60. The first UE of claim 59, wherein the one or more processors are configured to: send the one or more capability request messages, receive the one or more capability provide messages, obtain the SL-PRS configuration for each UE of the one or more additional UEs, and send the one or more assistance data provide messages within an SL Positioning Protocol (SLPP) positioning session.

70. 60. The first UE of claim 59, wherein the one or more processors are further configured to exchange a plurality of advance notice messages between the first UE and a server prior to the transmitting the one or more capability request messages, and wherein the one or more processors are configured to transmit the one or more capability request messages in response to the exchange of the plurality of advance notice messages.

71. 71. The first UE of claim 70, wherein to exchange the plurality of announcement messages, the one or more processors are configured to receive a capability request message or a location request from the server via the one or more transceivers.

72. 72. The first UE of claim 71, wherein the one or more processors are configured to receive the location request in a supplementary service request message.

73. a second user equipment (UE), one or more transceivers; one or more memories; one or more processors communicatively coupled to the one or more transceivers and the one or more memories, the one or more processors comprising: receiving, via direct wireless sidelink (SL) communication from a first UE via the one or more transceivers, a capability request message including a request for one or more capabilities to support SL position reference signals (SL-PRS) and SL-PRS measurements, wherein the second UE is one of one or more additional UEs, other than the first UE, used for positioning using SL communication; transmitting a capability provision message in response to the capability request message via the one or more transceivers to the first UE via the direct wireless SL communication; receiving a Provide Assistance Data message from the first UE via the one or more transceivers via direct wireless SL communication, the Provide Assistance Data message including an SL-PRS configuration for the second UE; one or more processors configured to: wherein the SL-PRS configuration is based at least in part on the capability provision message.

74. the one or more processors receiving a location information request message via the one or more transceivers from the first UE via direct wireless SL communication; performing one or more measurements of an SL-PRS according to the SL-PRS configuration for the second UE; and transmitting a location information providing message via the one or more transceivers to the first UE via the direct wireless SL communication, the content of the location information providing message being based on the one or more measurements. The second UE of claim 73.

75. 75. The second UE of claim 74, wherein the one or more processors are further configured to determine a position calculation based on the one or more measurements, and wherein the location information provide message includes the position calculation.

76. 75. The second UE of claim 74, wherein the one or more processors are further configured to include data indicative of the one or more measurements in the location information provide message.

77. 74. The second UE of claim 73, wherein the one or more processors are configured to use user plane signaling or control plane signaling in the direct wireless SL communication.

Images