Coordinated distributed ranging session including common devices

Abstract

Independent ranging sessions initiated by multiple initiating user equipments (UEs) are detected and combined into a single combined ranging session to reduce overhead. When the UE detects multiple ranging cycles within a predefined time, the independent ranging sessions can be determined to be close and simultaneous. The UE can send a message to each initiating UE indicating that the ranging sessions should be combined, and the initiating UE terminates the initiation of any further ranging sessions. The combined ranging session can be initiated by the UE and can include all participating UEs from the independent ranging sessions. The combined ranging session continues until it is determined that one or more UEs in the combined ranging session are not receiving ranging signals from other UEs.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the priority and benefit of U.S. Non - Provisional Application No. 17 / 184,403, filed on February 24, 2021, entitled "COMBINED DISTRIBUTED RANGING SESSIONS INCLUDING COMMON DEVICES", which was assigned to the assignee of this application and is hereby incorporated by reference in its entirety.

[0002] The subject matter disclosed herein relates to wireless communication systems, and more particularly, to methods and apparatus for ranging or positioning user equipment within a distributed wireless communication system.

Background Art

[0003] Obtaining accurate location information of user equipment such as cellular phones or other wireless communication devices is becoming common in the communication industry. For example, obtaining a very accurate location of a vehicle or pedestrian is essential for applications such as autonomous vehicle driving and pedestrian safety.

[0004] A common means for determining the location of a device is to use a satellite positioning system (SPS) such as the well - known Global Positioning System (GPS) or Global Navigation Satellite System (GNSS) that uses several satellites in earth - orbiting orbits. However, in some scenarios, for example, in adverse weather conditions or in areas with poor satellite signal reception such as tunnels or multi - level parking lots, the location - determination signals from the SPS may be unreliable or unavailable, and also, the location information generated using the SPS is likely to be inaccurate. For example, off - the - shelf GPS positioning devices have an accuracy of several meters, which is not optimal for ensuring safe autonomous driving and navigation.

[0005] Cooperative or autonomous driving requires communication between vehicles, which may be direct or indirect, for example, via infrastructure components such as roadside units (RSUs). For vehicle safety applications, both positioning and ranging are important. For example, a vehicle user device (UE) can perform positioning and ranging using side-link signaling, such as broadcasting ranging signals from other vehicle UEs or pedestrian UEs to determine the relative location of the transmitter. Knowing the relative location or distance to nearby vehicles accurately and in a timely manner allows autonomous vehicles to maneuver safely and navigate traffic conditions effectively. Round-trip time (RTT) is a technique commonly used, for example, to determine the distance between transmitters. RTT is a bidirectional messaging technique in which the time (minus processing delay) between sending a ranging signal from a first device and receiving an acknowledgment (e.g., in the form of a return ranging signal) from a second device corresponds to the distance (or range) between the two devices. [Overview of the project] [Means for solving the problem]

[0006] Independent ranging sessions initiated by multiple initiating user devices (UEs) are detected and combined into a single combined ranging session to reduce overhead. When a UE detects multiple ranging cycles within a given time, the independent ranging sessions can be determined to be close together and simultaneous. The UE can send a message to each initiating UE indicating that the ranging sessions should be combined, and the initiating UE will terminate the initiation of any further ranging sessions. A combined ranging session can be initiated by a UE and may include all participating UEs from the independent ranging sessions. A combined ranging session continues until it is determined that one or more UEs within the combined ranging session are not receiving ranging signals from other UEs.

[0007] In one embodiment, a method for measuring distance between UEs performed by a first user device (UE) includes the steps of: receiving start messages from multiple UEs to start separate distance measurement sessions; sending messages to the multiple UEs indicating that the first UE will start a combined distance measurement session in order to combine the separate distance measurement sessions; and having the multiple UEs perform the combined distance measurement session.

[0008] In one embodiment, a first UE configured to measure distance between user devices (UEs) comprises a wireless transceiver configured to wirelessly communicate with entities in a wireless network, at least one memory, and at least one processor coupled to the wireless transceiver and the at least one memory, wherein the at least one processor is configured to receive start messages from multiple UEs to start separate distance measurement sessions, send messages to the multiple UEs indicating that the first UE will start a combined distance measurement session in order to combine the separate distance measurement sessions, and have the multiple UEs perform the combined distance measurement session.

[0009] In one embodiment, a first UE configured to measure distance between user devices (UEs) includes means for receiving start messages from a plurality of UEs to start separate distance measurement sessions, means for sending messages to the plurality of UEs indicating that the first UE will start a combined distance measurement session in order to combine the separate distance measurement sessions, and means for the plurality of UEs to carry out the combined distance measurement session.

[0010] In one embodiment, a non-temporary storage medium including program code stored thereon, wherein the program code is operable to constitute at least one processor in a first UE for measuring distance between user devices (UEs), and the program code includes instructions for receiving start messages to start separate distance-measuring sessions from multiple UEs, sending messages to the multiple UEs indicating that the first UE will start a combined distance-measuring session in order to combine the separate distance-measuring sessions, and having the multiple UEs perform the combined distance-measuring session.

[0011] In one embodiment, a method for measuring distance between UEs performed by a first user device (UE) includes the steps of: sending a start message to a second UE to start a first distance measuring session; receiving a message from the second UE indicating that the second UE will start a combined distance measuring session in order to combine the first distance measuring session with a second distance measuring session started by a third UE; and having the second UE perform the combined distance measuring session.

[0012] In one embodiment, a first UE configured to measure distance between user devices (UEs) comprises a wireless transceiver configured to wirelessly communicate with entities in a wireless network, at least one memory, and at least one processor coupled to the wireless transceiver and the at least one memory, wherein the at least one processor is configured to send a start message to a second UE to start a first distance measurement session, receive a message from the second UE indicating that the second UE will start a combined distance measurement session in order to combine the first distance measurement session with a second distance measurement session started by a third UE, and have the second UE perform the combined distance measurement session.

[0013] In one embodiment, a first UE configured to measure distance between user devices (UEs) includes means for sending a start message to a second UE to start a first distance measurement session, means for receiving a message from the second UE indicating that the second UE will start a combined distance measurement session in order to combine the first distance measurement session with a second distance measurement session started by a third UE, and means for the second UE to carry out the combined distance measurement session.

[0014] In one embodiment, a non-temporary storage medium including program code stored thereon, wherein the program code is operable to constitute at least one processor in a first UE for measuring distance between user devices (UEs), and the program code includes instructions for sending a start message to a second UE to start a first measuring session, receiving a message from the second UE indicating that the second UE will start a combined measuring session in order to combine the first measuring session with a second measuring session started by a third UE, and having the second UE perform the combined measuring session.

[0015] The following diagrams describe non-exclusive and non-exclusive aspects, and unless otherwise specified, the same reference numbers refer to the same parts throughout the various diagrams. [Brief explanation of the drawing]

[0016] [Figure 1] This figure shows a wireless communication system exhibiting distributed communication, including ranging signaling to support multiple ranging sessions and / or positioning. [Figure 2] This figure shows a signaling graph illustrating the timing and frequencies of various messages that can be sent and received by the initiating UE and three response UEs for a ranging or positioning session. [Figure 3A] This diagram shows a system including multiple UEs participating in two independently initiated ranging sessions. [Figure 3B] This diagram is similar to Figure 3A, but shows a system in which independent ranging sessions are combined into a single combined ranging session. [Figure 4] This figure shows a visibility map that can be generated to determine the number of distance measurement signals lost during a combined distance measurement session. [Figure 5] This diagram shows the signaling flow for combining independent distance measurement sessions into a single distance measurement session. [Figure 6] This schematic block diagram illustrates specific exemplary features of a UE configured to combine independent ranging sessions into a single ranging session. [Figure 7] This is a flowchart showing the method for measuring the distance between UEs. [Figure 8] This is a flowchart showing the method for measuring the distance between UEs. [Modes for carrying out the invention]

[0017] Distributed methods can be used for ranging and positioning of vehicles, roadside units (RSUs), and pedestrians, avoiding the need for a central base station to coordinate and relay communications. Such communications can be used, for example, for autonomous driving and vehicle safety applications. Communications used in distributed methods can be, for example, directly between vehicles, or between vehicles and RSUs or pedestrians. These communications may include messages and information elements (IEs) that thereby provide vehicles with information necessary for autonomous driving.

[0018] For example, for the safe operation of an autonomous vehicle, it is necessary to determine the relative location or distance to other vehicles. Various techniques can be used to derive the relative position between vehicles. For example, the relative position of vehicles can be derived using ranging signaling. The ranging signal may be referred to as a physical ranging signal, a positioning ranging signal, a positioning reference signal, or a physical reference signal, and may be collectively referred to as a PRS signal herein. The PRS signal can be broadcast by a user equipment (UE) in a vehicle, sometimes referred to as a V-UE, using a direct communication system such as dedicated short-range communication (DSRC), cellular vehicle-to-everything (C-V2X) communication, and even 5G new radio (NR) communication, and can be received by other V-UEs and / or infrastructure such as a roadside unit (RSU) or a UE held by a pedestrian. The PRS signal is used to determine the distance to the broadcasting source vehicle using, for example, one-way ranging, round-trip time (RTT) positioning calculations, or other standard positioning calculations such as time of arrival (TOA), time difference of arrival (TDOA), or observed time difference of arrival (OTDOA).

[0019] In a distributed system, individual UEs can measure distance to other nearby UEs using messages and positioning signals directly transmitted to other UEs. For example, in an RTT-based ranging session, multiple messages and signals are sent and received by each UE. For instance, an initial set of pre-PRS messages is sent and received to request and approve the ranging session, followed by the broadcast of the ranging signal (PRS signal) for measurement, and then a set of post-PRS messages is broadcast to exchange the measurement payload. For example, for RTT-based ranging and positioning, the arrival time (TOA) and departure time (TOD) measurements of the transmitted and received PRS signals may be provided in the post-PRS messages and can be used by each pair of UEs to determine the distance between them. Pre-PRS and post-PRS messages may be sent over authorized spectra to ensure reliability, while PRS signals may be broadcast over unauthorized spectra (for example, to enjoy greater available bandwidth in the UNI-III spectrum). In a distributed system, a ranging session without infrastructure support for coordinating messaging can result in multiple simultaneous ranging sessions, which may include overlapping sets of participating UEs. Each ranging session may contain multiple messages and ranging signals exchanged between participating UEs, and each ranging session may contain multiple participating UEs. Therefore, when multiple ranging sessions occur simultaneously, the signaling overhead can become excessively large, potentially impairing ranging and positioning of the UEs.

[0020] The ranging mechanism guarantees minimizing overhead, but multiple neighboring UEs may start separate ranging sessions independently of each other. For example, without overhead communication for controlling the ranging session, two UEs may broadcast their own pre-PRS signals separately to the same set of response UEs, resulting in two independent ranging sessions that occur simultaneously and include the same response UEs. The number of messages exchanged within each separate ranging session can be large, especially when there are multiple response UEs. Additionally, some signaling, such as the PRS signal, may be broadcast via the unlicensed spectrum, which may cause transmission delays due to the listen-before-transmit (LBT) procedure used with the unlicensed spectrum. Therefore, when there are multiple overlapping ranging sessions, significant overhead may exist. The overhead may impair ranging and positioning in the session, for example, due to additional delays in received signaling.

[0021] Thus, in one embodiment, as discussed herein, independent ranging sessions can be combined into a single ranging session, thereby reducing the amount of signaling that must be exchanged between UEs. For example, a response UE that receives multiple pre-PRS messages from multiple initiating UEs for separate ranging sessions can send a message to the initiating UEs indicating that the separate ranging sessions should be combined and that the response UE will initiate the combined ranging session. The response UE then becomes the initiating UE by sending a pre-PRS message to start the combined ranging session. Upon receiving a message from the response UE that the ranging sessions are combined, the original initiating UE aborts the start of the ranging session and becomes the response UE for the combined ranging session.

[0022] Figure 1 shows a wireless communication system 100 demonstrating distributed communication, including ranging signaling to support multiple ranging sessions and / or positioning, as described herein. The wireless communication system 100 shows a first vehicle 102 having a first wireless device, such as a V-UE 102, which wirelessly communicates with another V-UE 104, shown as a second vehicle. V-UE 102 and V-UE 104 may include, but are not limited to, on-board units (OBUs), vehicles or subsystems thereof, or various other communication devices. V-UE 102 and 104 function and provide communication on behalf of their associated vehicles and may therefore be simply referred to herein as vehicles 102 and 104 or UE 102 and 104. The first UE 102 and the second UE 104 may be, for example, two vehicles traveling on a road together with other vehicles not shown.

[0023] The wireless communication system 100 may use, for example, a vehicle-to-everything (V2X) communication standard, in which information is passed between a vehicle and other entities within a wireless communication network. V2X services include, for example, vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P), vehicle-to-infrastructure (V2I), and vehicle-to-network (V2N) services. The V2X standard aims to develop autonomous or semi-autonomous driving systems, such as advanced driver-assistance systems (ADAS), which can be used to assist drivers in important decisions such as lane changes, speed changes, overtaking speeds, and to assist with parking, as discussed herein. Low-latency communication is used in V2X and is therefore suitable for precise relative positioning using ranging signals such as one-way ranging, RTT, TDOA, etc.

[0024] Generally, there are two operating modes for V2X services, as defined in the Third Generation Partnership Project (3GPP®) TS23.285. One operating mode uses direct wireless communication between V2X entities, which may be referred to as sidelink communication. The other operating mode uses network-based wireless communication between entities. The two operating modes may be combined, or other operating modes may be used, as desired.

[0025] The wireless communication system 100 can operate using direct or indirect wireless communication between UE 102 and UE 104. For example, wireless communication may be via a proximity-based services (ProSe) direct communication (PC5) reference point as defined in 3GPP® TS23.303, using wireless communication on the 5.9 GHz ITS band under IEEE 1609, Wireless Access in Vehicular Environments (WAVE), Intelligent Transport Systems (ITS), and IEEE 802.11p, or using other wireless connections directly between entities. Thus, as shown in the figure, UE 102 and UE 104 can communicate directly using vehicle-to-vehicle (V2V) communication link 103. Similarly, UE 102 and UE 104 can communicate directly with roadside units (RSUs) 110 via vehicle-to-roadway (V2I) communication links 107 and 109, respectively. RSU110 may include a backhaul connection to the network, indicated by a wired connection 111, which may also be via a wireless Uu interface to the base station. RSU110 may be a fixed infrastructure entity that supports, for example, V2X applications and can exchange messages with other entities that support V2X applications. RSU may be a logical entity that can combine V2X application logic with base station functions in the RAN, such as an eNB, ng-eNB, or eLTE (referred to as an eNB-type RSU) or gNB, or UE (referred to as a UE-type RSU). RSU110 can be used for ranging with UE102, 104 or other UEs, and since the location of RSU110 is precisely known, RSU110 can be used as an anchor UE that can thereby determine the location of UE102, 104 or other UEs. RSU110 may be referred to as UE110 in this specification.UE102, 104, and UE110 can communicate with additional entities such as additional vehicles, RSUs, or UE112 held by pedestrian 114 using direct communication links. For example, UE102 can communicate with UE112 via V2V communication link 113, UE104 can communicate with UE112 via V2V communication link 115, and UE110 can communicate with UE112 via V2I communication link 117.

[0026] During direct communication with one or more entities within the V2X wireless communication system 100, each entity may provide V2X information, such as an identifier for the V2X entity, as well as other information in messages, such as Common Awareness Messages (CAMs) and Distributed Notification Messages (DENMs) or Basic Safety Messages (BSMs), which can be used for ADAS or safety use cases.

[0027] In other embodiments, UE102 and UE104 can communicate indirectly with each other, for example, through RSU110 via V2I communication links 107 and 109, respectively, or through other network infrastructure (not shown) using, for example, cellular vehicle-to-everything (CV2X). For example, vehicles can communicate via base stations in a radio access network (RAN), such as advanced node B (eNB) or next-generation advanced node B (ng-eNB) in LTE wireless access and / or advanced LTE (eLTE) wireless access or NR node B (gNB) in fifth-generation (5G) wireless access.

[0028] UE102 and 104 can initiate and conduct a ranging / positioning session, including sending a pre-PRS message, broadcasting a PRS, and sending a post-PRS message over links 103, 107, 109, 113, or 115, which can determine the distance or relative position between UE102 and 104. The PRS broadcast by UE102 and 104 may be any signal suitable for ranging, such as those defined for DSRC or C-V2X. The PRS may be broadcast over licensed or unlicensed spectrum. For example, in some embodiments, the PRS may be broadcast over one or more unlicensed National Information Infrastructure (UNII) radio bands, including, for example, one or more of the UNII-1, UNII-2A, UNII-2B, or UNII-3 radio bands. When broadcasting over unlicensed spectrum, a Transmit Before Listen (LBT) protocol may be used.

[0029] When UE102 and 104 broadcast PRS on V2V link 103, the distance or relative position between UE102 and 104 can be directly determined. When UE102 and 104 broadcast PRS on V2I links 107 and 109 or via links 113 and 115, the distance and relative position between UE102 and UE110 or UE112, and between UE104 and UE110 or UE112, can be directly determined.

[0030] Direct wireless communication between UE102 and UE104, and between UE110 and UE112, requires no network infrastructure and enables low-latency communication, which is advantageous for precise ranging or positioning. Therefore, such direct wireless communication may be desirable, for example, for ranging over short distances to nearby vehicles or infrastructure.

[0031] For example, any of the UEs shown in Figure 1, such as V-UE102, V-UE104, RSU110, and UE112, can be configured to perform ranging and / or positioning operations, such as RTT-based ranging.

[0032] Figure 2 shows a signaling graph 200, as an example, illustrating the timing and frequencies of various messages that can be sent and received by an initiating UE (UEX) and three response UEs (UEA, UEB, and UEC) for a ranging or positioning session. For example, Figure 2 shows a possible message 201 and an RTT-based ranging session 202, during which several messages are sent between the initiating UE and the response UE, including a pre-PRS message 204 for requesting and acknowledging the ranging session, a PRS signal 206 for measurement, and a post-PRS message 208 for exchanging the measurement payload. Each set of pre-PRS 204, PRS 206, and post-PRS 208 can be considered a single unit or PRS cycle. Each PRS cycle includes a pre-PRS message 204, a PRS signal 206, and a post-PRS message 208, and may therefore be referred to herein as ranging session 202. The distance measurement session (PRS cycle) may be periodic with period T_r, and the possibility message may be periodic with period T_c, where T_r > T_c. In Figure 2, the signaling from the initiator UEX is shown by a white box labeled "X", the signaling from the first responder UEA is shown by a gray box labeled "A", the signaling from the second responder UEB is shown by a shaded box labeled "B", and the signaling from the third responder UEC is shown by a black box labeled "C". The signaling from the initiator UEX is the first box in each of the pre-PRS message 204, PRS signal 206, and post-PRS message 208, followed by the responding UEs (UEA, UEB, and UEC).

[0033] As shown in the figure, a UE including the initiating UE and the responding UE may broadcast a possibility message 201. Although the possibility message is not part of the ranging session, it may contain information that can be used by the initiating UE to initiate a ranging session with the selected UE. For example, the possibility message may be on the ITS spectrum and may include the UE ID, the ranging capability of the UE, the channel the UE is configured to use, MIMO (multi-input multiple-output) capability, etc. The possibility message may additionally indicate whether the UE needs to determine its location, or, if its location is known, whether it can act as an anchor UE for locating other UEs. The possibility message may additionally indicate whether the UE is capable of joining ranging sessions, or whether it is capable of allowing an initiated ranging session to be joined with another ranging session. Figure 2 shows the possibility message 201 as having the same order as the messages in ranging session 202, but it should be understood that the order may actually be different.

[0034] A pre-PRS message 204 (e.g., a pre-distance message) is used by the UE to request and acknowledge a distance measurement session. As shown in the figure, the pre-PRS message 204 may be transmitted over the authorization spectrum to ensure reliability. The pre-PRS message 204 may be broadcast or unicast, for example, by a Radio Resource Control (RRC) connection. The initiating UEX initiates a distance measurement session between the initiating UE and the responding UE and broadcasts an initial pre-PRS message 204 (pre-PRS request) (indicated by a white box labeled X) to provide information for the distance measurement session. For example, the pre-PRS message 204 from the initiating UE may include the IDs of the participating UEs, i.e., the initiating and responding IDs. The pre-PRS request message may include the distance measurement session ID, the PRS channel broadcast by the initiating UEX and responding UE, the PRS broadcast time, the maximum pre-transmit listen (LBT) time, etc. The pre-PRS request message from the initiating UEX may include, for example, the PRS ID to be used by the initiating UE, and, in some embodiments, the PRS ID to be used by the responding UE. If the PRS ID is fixed across multiple PRS exchanges (for example, for multiple units within a ranging session 202), the initiating UE may include an ID associated with the current PRS exchange, such as, for example, a session ID. The initiating UE can determine when the PRS signal 206 will be transmitted, which may consist of, for example, an upper layer within the initiating UE. The initiating UE may indicate the timing of the PRS by sending a time slot number close to the desired PRS transmission time. In some embodiments, the time slot may be subject to local clock error. The initiating UE may further provide the timing at which the PRS will be sent by the responding UE, and the maximum LBT time or other maximum predetermined delay for broadcasting the PRS. The initiating UE may further indicate the frequency that will be used by the initiating UE and the responding UE to broadcast the PRS signal 206.For example, the PRS frequency may be selected from an available set of total bandwidths, or the PRS frequency may be selected by selecting one or more channels that detect interference and whose average interference reference signal received power (RSRP) is below a threshold. The starting UE may indicate the number of PRS cycles to be performed during ranging session 202. The number of PRS cycles may be structured in upper layers. For example, the pre-PRS message for each PRS cycle may indicate the current PRS cycle relative to the requested total PRS cycles, where the number of current cycles increments after each cycle is completed.

[0035] An initial pre-PRS request message from the initiating UE is received and decoded by a responding UE identified within the initial pre-PRS message. The responding UE may respond by sending a pre-PRS message 204 (indicated by gray, shaded, and black boxes labeled A, B, and C respectively) that acknowledges the pre-PRS request message, which may additionally provide information about the ranging session. For example, each responding UE may determine the timing of its PRS signal 208 based on timing that takes into account, for example, the initiating UE's PRS timing plus delays that may occur based on hardware constraints and interference levels, as well as the number and order of responding UEs. For example, the delay may be relatively low when the PRS processing time is small and ambient interference is low, and relatively high when the PRS processing time is large and ambient interference is high. The responding UE may indicate the determined time of its PRS by sending a time slot number that is close to the determined PRS transmission time. In some embodiments, the time slot may be subject to local clock errors. Each responding UE may indicate the PRS ID it will use, or it may indicate that it will use the PRS ID indicated in the initial pre-PRS message. If the PRS ID is fixed across multiple PRS exchanges (for example, for multiple PRS cycles within a ranging session 202), the responding UE may include an ID associated with the current PRS exchange, such as a session ID, received in the initial pre-PRS message from the initiating UE. The responding UE can broadcast a pre-PRS message 204 that can be received by the initiating UE (and other responding UEs). In some embodiments, each responding UE can send a pre-PRS message 204 using unicast over an RRC connection to the initiating UE.

[0036] The PRS signal 206 is exchanged by the participating UEs. The initiating UE and responding UE know the predicted timing and frequency of the PRS signal and the PRS ID (and any session ID used by the exchanged signal) to broadcast the PRS signal 206. The PRS signal 206 may be, for example, a four-phase-shift keying (QPSK) modulated pseudo-noise (PN) sequence and may include a ranging session ID. The PRS signal 206 may be broadcast on an unlicensed spectrum which may be subject to LBT constraints. In some embodiments, when using an unlicensed spectrum, the initiating UEX may reserve the transmission of the responding UEs UEA, UEB, and UEC, thereby eliminating the need for the responding UEs to perform LBT. For example, the initiating UEX broadcasts its PRS signal 206 (a white box labeled X) at a determined time indicated in the initial pre-PRS message 204. In some embodiments, the initiating UE broadcasts the PRS signal at a time determined to account for random waiting times due to LBT constraints when the PRS signal is deployed in the unlicensed spectrum. In some embodiments, the LBT may be a Category 2 LBT with a fixed-window free channel evaluation (CCA) or a Category 4 LBT with a variable-window CCA. The initiating UE uses the PRS signal corresponding to the PRS ID and the frequency resources indicated in its initial pre-PRS message 204. The initiating UE stores the time the PRS signal was broadcast, and the responding UE stores the time the PRS signal was received. In some embodiments, the times may be subject to local clock errors.

[0037] Similar to the initiating UE, each responding UE broadcasts its PRS signal 206 (indicated by gray, shaded, and black boxes labeled A, B, and C, respectively) at the time and frequency allocated by the initiating UE in the initial pre-PRS message 204. In some embodiments, each responding UE may broadcast its PRS signal at a time determined, plus a time that accounts for random waiting times due to LBT constraints when the PRS signal unfolds in the unlicensed spectrum. In some embodiments, the LBT may be a Category 2 LBT with a fixed window CCA or a Category 4 LBT with a variable window CCA. Each responding UE uses a PRS signal corresponding to the PRS ID indicated in its pre-PRS message 204. Each responding UE stores the time its PRS signal was broadcast, and the initiating UE (and optionally other responding UEs) stores the time the PRS signal from each responding UE was received. In some embodiments, the times may be subject to local clock errors.

[0038] Thus, each UE records the departure time (ToD) of its broadcast PRS and measures the arrival time (ToA) of PRS signals received from other UEs. The PRS signal may be any signal suitable for ranging, such as a QPSK modulated PN sequence, as defined for DSRC or C-V2X. The ToA and ToD resolution of the PRS signal increases with increasing frequency bandwidth. In some embodiments, the departure angle (AoD) and arrival angle (AoA) of the broadcast and received PRS signals may also be measured. Broadcasting over the unlicensed spectrum is advantageous because a wider frequency bandwidth is available. For example, in some embodiments, the PRS may be broadcast over one or more UNII radio bands, including, for example, one or more of the UNII-1 radio band, UNII-2A radio band, UNII-2B radio band, or UNII-3 radio band.

[0039] To exchange measurement payloads, each UE sends a post-PRS message 208. As shown in the figure, the post-PRS message 208 may be transmitted over the authorization spectrum to ensure reliability. In some embodiments, the post-PRS message 208 may be broadcast or unicast by the RRC connection. The initiating UEX sends its post-PRS message 208 (shown as a white box labeled X) indicating when it broadcasts the PRS signal 206 (ToD) and when it receives the PRS signal from the responding UE (ToA). In some embodiments, ToA may be calculated as the relative time of the broadcast PRS signal to ToD, and the relative time may be provided. In some embodiments, the relative time may be approximated to the nearest multiple of the time scale shared by the initiating UE and the responding UE. In some embodiments, the initiating UE may provide an indication of its location in the post-PRS message 208, if known. For example, the initiating UE's location may be a location at a specific time, such as the broadcast time of its PRS signal or the arrival time of the PRS signal from the responding UE. The post-PRS message 208 may further include the AoD of the PRS signal 206 and the AoA of the PRS signal 206 received from the responding UE, the azimuth of the initiating UE, the broadcast index of the PRS signal 206, the received index of the PRS from the responding UE, and other relevant measurements such as map information and the location of reflectors relative to the UE.

[0040] Similar to the initiating UE, each responding UE sends its post-PRS message 208 (indicated by gray, shaded, and black boxes labeled A, B, and C, respectively) to provide a measurement payload. Each responding UE may indicate whether or not it has received a PRS signal from the initiating UE, and may indicate when it broadcast the PRS signal 206 (ToD) and when it received the PRS signal from the initiating UE (and optionally from other responding UEs) (ToA). In some embodiments, ToD may be calculated as the relative time of the PRS signal from the initiating UE to ToA (and optionally the PRS from other responding UEs to ToA). In some embodiments, the relative time may be approximated to the nearest multiple of the time scale shared by the initiating UE and the responding UEs. In some embodiments, if known, the responding UE may provide an indication of its location in the post-PRS message 208. For example, the location of the responding UE provided may be a location at a specific time, such as the time the PRS signal from the initiating UE arrives, or the time its broadcast PRS signal departs. The post-PRS message 208 may further include the AoD of the PRS signal 206, the AoA of the PRS signal 206 received from the initiator UEX (and optionally from other responding UEs), the azimuth of the initiator UE, the broadcast index of the PRS signal 206, the received index of the PRS from the responding UE, and other relevant measurements such as map information and the location of reflectors relative to the UE.

[0041] After receiving the post-PRS message, the initiating UE can, for example, use a Kalman filter to calculate its distance (and, in some embodiments, its location), and then send the next cycle of pre-PRS messages at a time indicated by the upper layer or determined autonomously by the initiating UE.

[0042] The time between the first pre-PRS message 204 and the last post-PRS message 208 may be the duration of the ranging session, for example, 100 milliseconds. The duration of each broadcast 206 signal 206 may be, for example, 47 microseconds. Depending on the embodiment, multiple PRS cycles, such as multiple instances of the pre-PRS message 204, PRS 206, and post-PRS message 208, can be used together to provide higher accuracy.

[0043] Both the initiating UE and the responding UE can determine the distance between themselves and each other UE in the ranging session based on the ToD and ToA of the broadcast PRS signal. For example, the RTT between any pair of UEs (which may be any pair of initiating UE and responding UE) can be calculated, for example, as follows: i Signal ToD i and ToA i Based on (i=1 of the PRS broadcast from the first UE and i=2 of the PRS broadcast from the second UE), it can be determined as the difference between ToD1 and ToA2 minus the difference between ToA1 and ToD2. RTT = (ToD1 - ToA2) - (ToA1 - ToD2) Equation 1

[0044] The RTT value is the round-trip time of a signal, and therefore the distance (range or distance) between UE1 and UE2 can be determined as RTT / 2c, where c is the speed of light.

[0045] If the locations of one or more response UEs are known, the distance between the starting UE and the response UEs can be used, along with the known location of one response UE, to determine the locations of the other UEs, thus enabling a ranging session to become a positioning session. A known response UE that can be used for positioning may be referred to herein as an anchor UE. The location of an anchor UE can be provided to other UEs through messaging, for example, in a pre-PRS message or post-PRS message. If the distances to multiple anchor UEs are determined, the locations of multiple anchor UEs can be used in multilateration to determine the location of the starting UE (or other response UEs).

[0046] For example, angular measurements such as AoD and AoA can be used, for example, to aid in positioning. As an example, the relative positions of two UEs can be determined based on the distance between them and the measured AoA. Once the relative positions of the UEs are determined, the actual position of one UE can be determined if its actual position is known (for example, provided in a pre-PRS message 204 or post-PRS message 208). If the positions of two UEs are known by a third UE, the distance between the third UE and each of the other two UEs will generate two possible positions for the third UE, which can be resolved based on AoD / AoA information. AoD may be useful, for example, when the resolution of AoA is unsatisfactory or inaccurate. AoD may be measured, for example, based on the known azimuth of the UE (for example, determined by a magnetometer) and the direction of the transmitted signal relative to the UE (for example, relative to the antenna array of the UE used for beamforming). AoA may be measured based on the phase difference of the received signals at different antenna elements of the antenna array and the known orientation of the UE (e.g., determined by a magnetometer). Additionally, geographical constraints can be used to assist positioning, for example, by constraining the possible positions of the vehicle based on locations accessible to the vehicle, such as roads.

[0047] As described above, due to the distributed mechanism for ranging, it is possible for multiple UEs to initiate independent ranging sessions, each containing at least a portion of the same response UEs, almost simultaneously. For example, two initiating UEs may separately broadcast their own pre-PRS signals to the same set of response UEs, resulting in two independent ranging sessions occurring simultaneously, each containing the same response UEs.

[0048] Figure 3A shows a system 300 including multiple UEs participating in two independent ranging sessions, which may be initiated separately by UE1 302 and UE2 304, which may be pedestrian UEs, vehicle UEs, etc. For example, initiating UE1 302 and initiating UE2 304 can initiate a ranging session by sending pre-PRS messages (indicated by arrows 303 and 305, respectively) to responding UEs, which may be collectively referred to as UE310, including UEA 310A, UEB 310B, and UEC 310C, which may not be able to detect each other due to distance, for example, and may be RSUs, pedestrian UEs, vehicle UEs, etc. The pre-PRS messages 303 and 305 may be broadcast or unicast messages.

[0049] As shown in Figure 3A, two simultaneous ranging sessions involving the same set of responding UEs result in significant overhead. For example, each PRS cycle in the ranging session initiated by UE1 302 includes a UE1 PRS pre-message, a UEA / UEB / UECPRS pre-message, a UE1 PRS signal, a UEA / UEB / UEC PRS signal, a UE1 PRS post-message, and a UEA / UEB / UECPRS post-message, while each PRS cycle in the other ranging session initiated by UE2 304 includes a UE2 PRS pre-message, a UEA / UEB / UECPRS pre-message, a UE2 PRS signal, a UEA / UEB / UEC PRS signal, a UE2 PRS post-message, and a UEA / UEB / UECPRS post-message. For example, since the PRS signals are constrained by the LBT procedure, the resulting large signaling overhead will impair ranging and positioning for the initiating UEs, UE1 and UE2.

[0050] Therefore, it is desirable to combine two ranging sessions by, for example, changing the starting UE from, for example, two starting UEs (UE1 302 and UE2 304) to a single starting UE, for example, UEA 310A.

[0051] Figure 3B shows, as an example, a system 350 in which independent ranging sessions, such as those shown in Figure 3A, are combined into a single ranging session. System 350 is similar to system 300 shown in Figure 3A, and the same designation elements are the same.

[0052] In Figure 3B, after confirming the existence of multiple proximity ranging sessions, such as the ranging session initiated by UE1 302 and UE2 304 in Figure 3A, the UEA 310A can combine the two ranging sessions into a single ranging session that includes both the initiating UEs, such as UE1 302 and UE2 304, and the responding UE 310. As shown in Figure 3B, the UEA 310A, which was the responding UE in both ranging sessions initiated by UE1 302 and UE2 304 in Figure 3A, can act as the initiating UE for the combined ranging session in Figure 3B. The responding UE (e.g., UEA 310A) can initiate a new combined ranging session that includes participants (shown in Figure 3A) from a separate ranging session. For example, as shown in Figure 3B, UEA 310A may send a pre-PRS message (indicated by arrows 353-1, 353-3, 353-B, and 353-C (sometimes collectively referred to as pre-PRS message 353)) to the response UEs of a new coupled ranging session, such as UE1 302, UE2 304, UEB 310B, and UEC 310C. The pre-PRS message 353 may be a broadcast or unicast message.

[0053] The coupled ranging session may then proceed with UEA-310A acting as the starting UE and UE1 302, UE2 304, UEB 310B, and UEC 310C acting as response UEs. The coupled ranging session may include pre-PRS messages, PRS signals, and post-PRS messages as described above. The post-PRS messages in the coupled ranging session are broadcast to the original starting UEs (UE1 302 and UE2 304), who, while acting as response UEs in the coupled ranging session, receive PRS measurement information from each response UE to determine their distance to other new starting UEs (UEA-310A) and other response UEs, UEB 310B and UEC 310C, and, depending on the embodiment, their positions.

[0054] The initiating UE of a coupled ranging session (e.g., UEA 310A) can continue to initiate the coupled ranging session for a predetermined period of time, or until the participants of the coupled ranging session are no longer visible to the other participants. For example, in a coupled ranging session, the PRS signals from each participant (e.g., from initiating UEA-310A and response UE1 302, UE2 304, UEB 310B, and UEC 310C) should be visible to each of the other participants. If the PRS signals from the participants of the coupled ranging session become invisible to other group members more than, for example, N times, the coupled ranging session may end, and the original initiating UEs 302 and 304 may then initiate separate ranging sessions again. For example, the start UEA 310A of a coupled ranging session may send a message (e.g., a V2X message) to the original start UEs 302 and 304 indicating that the coupled ranging session should be separated, and the UEA 310A may stop the start of a new coupled ranging session, and the original start UEs 302 and 304 may start a separate ranging session with appropriate response UEs, which may be a different set of response UEs than those included in the coupled ranging session.

[0055] For example, in one embodiment, the initiating UE of a coupled ranging session (e.g., UEA 310A) can monitor which PRS signals from other participants are visible (or lost) in each coupled ranging session. Figure 4 shows, as an example, a visibility map 400 that can be generated to determine the number of lost PRS signals during each coupled ranging session. As shown, each participating UE in a coupled ranging session may be included in the visibility map 400, although in some embodiments, only the original initiating UE and initiating UEA, such as UE1 and UE2, may be considered. Along each row, the visibility map 400 indicates whether a UE receives a PRS signal from another participating UE. For example, in row 402, initiating UEA 310A is shown as receiving PRS signals from UE1, UE2, and UEC, but not from UEB. Ideally, the visibility of PRS signals should be symmetrical; that is, if a PRS signal from UEB 310B is visible to UEA 310A, then a PRS signal from UEA 310A should be visible to UEB 310B.

[0056] The initiating UEA 310A can monitor multiple instances of a combined ranging session, and if the number of PRS signals lost from other participants in the combined ranging session exceeds a predetermined threshold N, the combined ranging session may be separated. In some embodiments, the threshold N may be used for all combined ranging sessions, or it may be used for a conservative number of preceding combined ranging sessions, such as N of the last 10 combined ranging sessions. In some embodiments, the initiating UEA 310A may additionally or alternatively monitor post-PRS messages from each responding UE to determine the number of PRS signals lost by each responding UE, and if the responding UE loses more than the threshold number of PRS signals, the combined ranging session may be separated. In particular, the initiating UEA 310A may consider the number of PRS signals lost by the original initiating UE, such as UE1 and UE2, while the number of PRS signals lost by other responding UEs, such as UEB and UEC, may be irrelevant to whether the combined ranging session should be separated. In another embodiment, each response UE, in particular the original initiating UEs such as UE1 and UE2, can independently monitor the number of lost PRS signals and send a message to the initiating UEA 310A indicating when more than a threshold number of PRS signals have been lost. It should be noted that PRS signals from the original initiating UEs 302 and 304 may not be visible to each other, and therefore it may not be desirable to consider lost PRS signals between the original initiating UEs when determining whether a threshold number of PRS signals have been lost.

[0057] The initiating UEA 310A can determine, based on their post-PRS messages or other messages provided by other UEs, whether other participating UEs, and in particular the original initiating UEs such as UE1 and UE2, have received PRS signals from other UEs. Multiple visibility maps can be combined to determine whether the total number of PRS signals for all combined ranging sessions (or a conservative number of preceding combined ranging sessions) is greater than a threshold. For example, the initiating UEA 310A may monitor only the number of PRS signals it itself has lost sight of, or only the number of PRS signals lost by a combination of participating UEs, such as the original initiating UEs, UE1 and UE2, for example. In some embodiments, the initiating UEA 310A may consider only the PRS signals lost by the original initiating UE1 and UE2.

[0058] Figure 5 shows an example of a signaling flow 500 for combining independent ranging sessions into a single combined ranging session. For example, UE entities 302, 304, 310A, 310B, and 310C may be V-UEs, RSUs, and / or pedestrian UEs, such as UE102, 104, 110, or 112, as shown in Figure 1 and discussed in Figures 3A and 3B and Figure 4. The original initiating UEs may be UE1 302 and UE2 304, and the original responding UEs may be UEA 310A, UEB 310B, and UEC 310C. It should be understood that there may be additional (or fewer) responding UEs with additional (or fewer) communications similar to those shown in Figure 5. As illustrated, the communication between UEs in Figure 6 may be direct communication between entities and may not involve infrastructure devices such as base stations to transfer messages between entities. It should be further understood that Figure 5 shows signaling for joining independent ranging sessions, and that additional or other communications may be transmitted between one or more of the UEs shown in Figure 5 via broadcast, unicast, multicast, or other sidelink signaling, or through one or more infrastructure devices such as the RSU110 or base stations.

[0059] In stage 1A, one or more ranging and / or positioning sessions are conducted by UE1 302, which acts as the initiating UE, and UEA 310A, UEB 310B, and UEC 310C, which act as the responding UEs. Participating UEs in the ranging session in stage 1A can be identified / selected based on possibility messages, such as message 201 shown in Figure 2, in which the UEs provide their identifiers, ranging feasibility, configured channels, etc. For example, possibility messages from responding UEs such as UEA 310A, UEB 310B, and UEC 310C may further indicate whether the UEs are capable of joining ranging sessions, while possibility messages from initiating UE1 302 may indicate whether the ranging session being initiated can be joined with another ranging session. The ranging session in stage 1A does not necessarily include UE2 304. For example, as discussed in Figure 2, each distance measurement session may include, for example, an initial pre-distance message from the starting UE (e.g., a pre-PRS message) and a response pre-distance message from the response UE (e.g., a pre-PRS message). Each distance measurement session may further include distance measurement signals (PRS signals) from the starting UE and response UE, as discussed in Figure 2, and post-distance measurement signals (post-PRS messages) from the starting UE and response UE that carry measurement information for the distance measurement signals. The starting UE can use the measurement information to determine the distance to each response UE. The response UE can similarly determine distance or timing information to the starting UE and other response UEs, which can be used for clock synchronization. Post-distance measurement messages from the anchor UE may include location information, which in turn allows the position of the UE to be determined based on location information and the determined distance to the anchor UE.

[0060] In stage 1B, similar to stage 1A, one or more ranging and / or positioning sessions are conducted by UE2 304, which acts as the initiating UE, and UEA 310A, UEB 310B, and UEC 310C, which act as the responding UEs. Participating UEs in a ranging session in stage 1B can be identified / selected based on possibility messages, such as message 201 shown in Figure 2, in which the UEs provide their identifiers, ranging feasibility, configured channels, etc. For example, possibility messages from responding UEs such as UEA 310A, UEB 310B, and UEC 310C may further indicate whether the UEs are capable of joining ranging sessions, while possibility messages from initiating UE2 304 may indicate whether the ranging session being initiated can be joined with another ranging session. A ranging session in stage 1B does not necessarily include UE1 302. The ranging and / or positioning session initiated by UE2 304 may be adjacent to and concurrent with the ranging and / or positioning session of stage 1A.

[0061] In stage 2A, UEA 310A decides to combine the simultaneous ranging sessions initiated by UE302 and 304. UEA 310A can decide whether to combine simultaneous ranging sessions if, for example, possible messages from initiating UE1 302 and UE2 304 (e.g., message 201 in Figure 2) indicate that the ranging sessions initiated by them can be combined with other ranging sessions. For example, UEA 310A can confirm the existence of multiple simultaneous ranging sessions by receiving pre-PRS messages from initiating UE302 and 304 in the ranging sessions of stages 1A and 1B. UEA 310A can confirm the existence of multiple independent ranging sessions based on pre-PRS messages in each ranging session, which may enumerate all participating UEs (including initiating UE302 and 304 and responding UE310, respectively). For example, in some embodiments where pre-PRS messages 303 and 305 are unicast, the UEA 310A can detect the presence of multiple adjacent ranging sessions by sending multiple PRS cycles in both the Stage 1A and Stage 1B ranging sessions within a certain time period. For example, the UEA 310A can detect whether the number of PRS signals received from the starting UEs 302 and 304 exceeds a predetermined number (X) within a certain time period, such as every second (where X is any value from 0 to 10, given that the PRS period is 100 milliseconds, i.e., 100 milliseconds = 1 second / 10 PRS). In some embodiments, the UEA 310A can detect the number of pre-PRS messages and / or post-PRS messages received from the starting UEs 302 and 304 in the Stage 1A and Stage 1B ranging sessions within a certain time period. The post-PRS message may include, for example, the departure time (ToD) of the broadcast PRS signal and can be used to assist in determining the number of PRS cycles from each starting UE.Depending on the embodiment, the UEA 310A may further detect the number of PRSs broadcast from response UEs, such as UEB 310B and UEC 310C, within that time period. If the UEA 310A detects multiple PRS cycles from multiple ranging sessions within that time period, the UEA 310A may determine that the independent ranging sessions from stages 1A and 1B are simultaneous and should be combined.

[0062] In stage 2B, it can be determined that one or more other response UEs, indicated as UEB 310B, should also be combined with the ranging sessions from stages 1A and 1B as described in stage 2A.

[0063] In stage 3A, UEA 310A can send a coupling message (e.g., a V2X message) to each of the initiating UEs 302 and 304 indicating that the ranging sessions will be coupled. UEA 310A can indicate whether it can act as a positioning anchor for the positioning of UEs 302 and 304 (i.e., whether the location of UEA 310A is precisely known). UEA 310A can further measure one or more power characteristics of the PRS signals broadcast by each of the initiating UEs 302 and 304 during the ranging sessions in stages 1A and 1B, and can provide indications of the power characteristics of the PRS signals from initiating UEs 302 and 304 in the coupling message in stage 3A. For example, UEA 310A can measure the RSRP of the PRS signals from both UE1 302 and UE2 304 and determine the average RSRP of the PRS signals. The UEA 310A can include the average RSRP of the PRS signals from UE1 302 and UE2 304 in the combined message.

[0064] In stage 3B, if UEB 310B has decided in stage 2B to combine the ranging sessions, UEB 310B may also send a combine message (e.g., a V2X message) to each of the initiating UE302 and 304 indicating that the ranging sessions are combined, providing an indication of whether UEB 310B can act as a positioning anchor, as well as an indication of the measured power characteristics of the PRS signals, such as the average RSRP of the PRS signals from UE1 302 and UE2 304 measured by UEB 310B.

[0065] In stages 4A and 4B, start UE1 302 and start UE304 can each select a start UE for a combined ranging session and stop starting independent ranging sessions. Therefore, when a message to combine ranging sessions is received from UEA 310A, two start UEs, such as UE1 302 and UE2 304, will stop starting a new ranging session, i.e., any subsequent starts of ranging sessions by two start UEs, such as UE1 302 and UE2 304, will be observed. Start UE302 and 304 wait to become the response UEs for the combined ranging session and select a start UE for the combined ranging session. For example, if only one response UE (e.g., UEA 310A) sends a combine message, UE302 and 304 may select that single response UE. If initiating UEs 302 and 304 receive coupling messages from two or more response UEs indicating that their ranging sessions will be combined, for example, in stages 3A and 3B, initiating UEs 302 and 304 can determine which response UE will act as the new initiating UE in the combined ranging session, based on criteria such as anchor status and power characteristics provided in the coupling message from each response UE. For example, a response UE capable of acting as an anchor point for positioning may be preferred over a response UE that cannot act as an anchor point, and / or a response UE with a high average RSRP may be preferred over a response UE with a low average RSRP. Depending on the embodiment, initiating UEs 302 and 304 may determine which response UE will be the new initiating UE based on a combination of ordered criteria, such as anchors with high average RSRP > anchors with low average RSRP > non-anchors with high average RSRP > non-anchors with low average RSRP. Other criteria, combinations of criteria, or orders may be used as desired.

[0066] In stage 5, each initiating UE 302 and 304 provides a response coupling message (e.g., a V2X message) to the selected response UE (e.g., UEA 310A in Figure 5) indicating that it is a response UE, and provides instructions that the response UE should start a coupled ranging session. The response UE that sent the coupling message to the initiating UEs 302 and 304 can start a coupled ranging or positioning session if it receives a response message from the initiating UEs 302 and 304.

[0067] In stage 6, UEA 310A initiates one or more coupled ranging or positioning sessions, including the original starting UEs, namely UE1 302 and UE2 304, as response UEs along with UEB 310B and UEC 310C. The coupled ranging sessions may be similar to the independent ranging sessions in stages 1A and 1B, but UEA 310A initiates the ranging session, and the previous starting UEs (UE1 302 and UE2 304) act as response UEs. For example, as discussed in Figure 2, each ranging session may include, for example, an initial pre-ranging message from the starting UE (e.g., a pre-PRS message) and a response pre-ranging message from the response UE (e.g., a pre-PRS message). Each ranging session may further include ranging signals (PRS signals) from the starting UE and response UE, as well as post-ranging signals (post-PRS messages) from the starting UE and response UE that carry measurement information for the ranging signals. Post-measurement messages from the anchor UE may include location information that allows the position of the UE to be determined based on the determined distance to the anchor UE and the location information. Post-PRS messages in a coupled ranging session are broadcast to receive PRS measurement information from each responding UE to determine their distance to other new starting UEs (UEA-310A) and other responding UEs, UEB 310B and UEC 310C, as well as their positions, as discussed above, while the previous starting UEs (UE1 302 and UE2 304) act as responding UEs in the coupled ranging session. UEA 310A, UEB 310B, and UEC 310C can similarly determine distance or timing information to participating UEs that can be used for clock synchronization.

[0068] In stage 7A, the initiating UEA 310A can decide whether or not to separate the coupled ranging session from stage 6. In some embodiments, as shown by the optional stage 7B, another UE may decide whether or not to separate the coupled ranging session from stage 6. Although Figure 5 shows stages 7A and 7B as occurring after stage 6, it should be understood that in practice, stages 7A and 7B occur concurrently with the coupled ranging session from stage 6. In stage 7A, for example, the initiating UEA 310A of a coupled ranging session can continue to run the coupled ranging session for a predetermined period of time, or until participants in the coupled ranging session are no longer visible to other participants. For example, the initiating UEA 310A can monitor which PRS signals from other participants are visible (or lost) in each coupled ranging session, as described above with reference to Figure 4, for example. The initiating UEA 310A can monitor multiple coupled ranging sessions, and if the number of PRS signals from other participants in a coupled ranging session exceeds a predetermined threshold N, the coupled ranging session may be separated. In some embodiments, the threshold N may be used for all coupled ranging sessions, or it may be used for a conservative number of preceding coupled ranging sessions, such as N of the last 10 coupled ranging sessions. In some embodiments, the initiating UEA 310A may additionally or alternatively monitor post-PRS messages from each responding UE to determine the number of PRS signals that each responding UE has lost track of, and may isolate the coupled ranging session if more than a threshold number of PRS signals have been lost by the responding UE. In another embodiment, each responding UE may independently monitor the number of PRS signals it has lost track of (for example, as shown by stage 7B), and may send a message to the initiating UEA 310A indicating that more than a threshold number of PRS signals have been lost. The initiating UEA 310A may determine whether other participating UEs have received PRS signals based on their post-PRS messages or other messages provided by other UEs.The start UEA 310A may monitor, for example, only the number of PRS signals it itself has lost, or the number of PRS signals lost by a combination of participating UEs (which may or may not include the original start UE1 and UE2). In some embodiments, the start UEA 310A may consider only the PRS signals lost by the original start UE1 and UE2.

[0069] In stage 8, if UEA 310A determines that the coupled ranging session should be separated, UEA 310A sends a separation message (e.g., a V2X message) to the original initiating UE302 and 304 indicating that the coupled ranging session should be separated, and stops the initiation of the coupled ranging session.

[0070] In stages 9A and 9B, the original start UEs 302 and 304 initiate a separate ranging session with appropriate response UEs, which may be the same or a different set of response UEs as those included in the combined ranging session.

[0071] Therefore, decisions to merge and separate ranging sessions can be made autonomously and without the assistance of a central network. Multiple adjacent ranging sessions can be merged to reduce signaling overhead, thereby increasing the accuracy of ranging between UEs across groups, and can be separated when the benefits of the merged ranging sessions are reduced or lost.

[0072] Figure 6 is a schematic block diagram showing specific exemplary features of UE600, which may be a user device (UE) 600 in a vehicle 102 or 104 as shown in Figure 1, an RSU 110, or a UE 112 held by a pedestrian 114, or any UE shown in Figures 3A, 3B, 4, or 5. UE600 can be configured to act, for example, as a response UE such as response UEA 310A, or as a start UE such as start UE1 302, where multiple independent simultaneous ranging sessions are combined into a single combined ranging session, as discussed herein. If UE600 is a V-UE, it can be configured to control the autonomous driving of a vehicle, for example, vehicle 102. For example, UE600 may include a vehicle interface 605, through which commands for autonomous driving are provided to the vehicle, and sensory inputs, including speed and acceleration, may be provided from the vehicle to UE600. The UE600 may include, for example, one or more processors 602, memory 604, an inertial measuring unit (IMU) 607 which may include, for example, an accelerometer, gyroscope, magnetometer, etc., that can be used to detect the vehicle's orientation to a global or local reference coordinate system and motion, or one or more motion characteristics, a satellite positioning system (SPS) receiver 609 for determining GPS position, etc., and an external interface which may include, for example, a wireless wide area network (WWAN) transceiver 610 and a wireless local area network (WLAN) transceiver 614, which can be operably coupled to a non-temporary computer-readable medium 620 and memory 604 by one or more connections 606 (for example, a bus, line, fiber, link, etc.). The UE600 may further include additional items not shown, such as a user interface which may include, for example, a display, a keypad, or other input devices such as a virtual keypad on the display through which the user can interface with a user device. In some exemplary embodiments, all or part of the UE600 may be in the form of a chipset or the like.

[0073] Transceiver 610 may be a cellular transceiver, for example, configured to send and receive communications directly within a wireless network, as shown in Figure 1. Transceiver 610 may include a transmitter 611 capable of transmitting one or more signals over one or more types of wireless communication networks, and a receiver 612 for receiving one or more signals transmitted over one or more types of wireless communication networks. Transceiver 614 may be a short-range transceiver, for example, and may be configured to send and receive communications directly within a wireless network, as shown in Figure 1. Transceiver 614 may include a transmitter 615 capable of transmitting one or more signals including a distance measurement signal (PRS signal) and pre-PRS and post-PRS messages, and for combining and separating messages over one or more types of wireless communication networks, and a receiver 616 for receiving one or more signals including PRS and pre-PRS and post-PRS messages, and for combining and separating messages transmitted over one or more types of wireless communication networks. Transceivers 610 and 614 enable the UE600 to communicate with transport entities using D2D communication links such as DSRC, C-V2X, or 5G NR.

[0074] In some embodiments, the UE600 may include an antenna 609, which may be internal or external. The antenna 609 may be used to transmit and / or receive signals processed by transceivers 610 and / or transceivers 614. In some embodiments, the antenna 609 may be coupled to transceivers 610 and / or transceivers 614. In some embodiments, the measurement of the signal received (transmitted) by the UE600 may be performed at the connection point of the antenna 609 and transceivers 610 and / or transceivers 614. For example, the reference point for the measurement of the received (transmitted) RF signal may be the input (output) terminals of receivers 612, 616 (transmitters 611, 615) and the output (input) terminals of antenna 609. In a UE600 with multiple antennas 609 or antenna arrays, the antenna connector may be considered a virtual point representing the aggregated output (input) of the multiple antennas. The phase difference of the received signals across multiple antennas or antenna arrays can be used to determine the AoA of the signal relative to the antenna array, which can then be transformed to a global or local reference coordinate system based on the known orientation of the UE600, for example, based on the orientation of the UE600 relative to a global or local reference coordinate system as measured by the IMU607.

[0075] One or more processors 602 may be implemented using a combination of hardware, firmware, and software. For example, one or more processors 602 may be configured to perform the functions described herein by implementing one or more instructions or program code 608 on a non-temporary computer-readable medium such as medium 620 and / or memory 604. In some embodiments, one or more processors 602 may represent one or more circuits that can be configured to perform at least a portion of a data signal calculation procedure or process relating to the operation of UE600.

[0076] The medium 620 and / or memory 604 may store instructions or program code 608, which, when executed by one or more processors 602, cause one or more processors 602 to operate as a dedicated computer programmed to perform the techniques disclosed herein. As shown in UE600, the medium 620 and / or memory 604 may include one or more components or modules that can be implemented by one or more processors 602 to perform the methods described herein. Although the components or modules are shown as software in the medium 620 that can be executed by one or more processors 602, it should be understood that the components or modules may be stored in memory 604 or may be dedicated hardware located either in or outside of one or more processors 602.

[0077] Several software modules and data tables may reside in the medium 620 and / or memory 604 and may be utilized by one or more processors 602 to manage both the communications and functions described herein. It should be understood that the organization of the contents of the medium 620 and / or memory 604 as shown in UE600 is illustrative, and the functions of the modules and / or data structures may be combined, separated, and / or constructed in various ways depending on the embodiment of UE600.

[0078] The medium 620 and / or memory 604, when implemented by one or more processors 602, may include a pre-PRS message module 622 that configures one or more processors 602 to generate and transmit or receive pre-PRS messages, such as pre-PRS messages, via a transceiver 614, for example, to initiate or accredit a ranging session. Pre-PRS messages may be broadcast, multicast, or unicast (by an RRC connection). In some embodiments, PRS messages may be transmitted and received over the authorization spectrum. A pre-PRS message may be an initiating pre-PRS message to initiate a ranging session or a response pre-PRS message to acknowledge an initiating pre-PRS message. A pre-PRS message may include identifiers for the initiating UE and one or more response UEs. Participating UEs can be determined, for example, from potential messages received by UE 600, or by monitoring multiple simultaneous ranging sessions and identifying participating UEs from simultaneous ranging sessions. A pre-PRS message may further include ranging signal characteristics used in the ranging session and may include location information of UE 600. For example, the pre-PRS message may include an identifier for the ranging signal, timing information for the ranging signal (e.g., time slot number), and the frequency to be used to broadcast the ranging signal. For example, the frequency can be selected from an available bandwidth set and by detecting interference and selecting a channel with an average interference RSRP below a threshold. Depending on the embodiment, the start pre-PRS message may include an indication of the number of PRS cycles requested and the current PRS cycle.

[0079] The medium 620 and / or memory 604, when implemented by one or more processors 602, may include a PRS module 624 that configures one or more processors 602 to broadcast and receive ranging signals to other UEs in a ranging session via a transceiver 614, as discussed herein. The ranging signal may be, for example, a PRS signal as discussed herein. The ranging signal may be broadcast at a frequency indicated via a pre-PRS message, along with an identifier, at a determined time. The ranging signal may be broadcast and received via an unlicensed spectrum and may be broadcast in accordance with Category 2 or Category 4 LBT constraints. For example, one or more processors 602 may be configured to measure the ToD of a broadcast ranging signal and the ToA of a received ranging signal, and may be configured to measure the AoD of a broadcast ranging signal and the AoA of a received ranging signal.

[0080] The medium 620 and / or memory 604, when implemented by one or more processors 602, may include a post-PRS message module 626 that configures one or more processors 602 to send and receive post-PRS messages to and from other UEs in the ranging session via transceiver 614, as discussed herein. The post-PRS message may include, for example, an indication of the ToD of the broadcast ranging signal and, in an embodiment, an AoD, as well as an indication of the ToA of the received ranging signal and, in an embodiment, an AoA. In an embodiment, the indications of ToD and ToA may be the difference between ToD and ToA. In an embodiment, the post-PRS message may include an indication of the location of the UE.

[0081] The medium 620 and / or memory 604 may include a ranging / positioning module 628, which, when implemented by one or more processors 602, configures one or more processors 602 to determine the distance to another UE based on the ToD and ToA of broadcast and received ranging signals, as measured by UE 600 and received in a post-PRS message from another UE. The processors 602 may be further configured to determine the position of UE 600 based, for example, on the distance to one or more broadcasting UEs and their location information, using multilateration or other suitable techniques discussed herein. For example, one or more processors 602 may implement a Kalman filter or an extended Kalman filter to determine the distance to other UEs and / or the position of UE 600.

[0082] The medium 620 and / or memory 604 may include a session coupling module 630, which, when implemented by one or more processors 602, configures one or more processors 602 to check for the existence of independent, concurrent ranging sessions initiated by different starting UEs. One or more processors 602 may be configured to determine the existence of independent, concurrent ranging sessions based on pre-PRS messages of each ranging session, which can enumerate all participating UEs, including different starting UEs. In some embodiments, one or more processors 602 may be configured to determine the existence of independent, concurrent ranging sessions by detecting whether the number of PRS cycles in both ranging sessions exceeds a threshold within a certain time period. The number of PRS cycles can be determined by monitoring the number of PRS signal broadcasts or post-PRS messages, etc. If the number of PRS cycles from multiple ranging sessions exceeds the threshold within the time period, the independent ranging sessions can be considered concurrent and determined to be coupled. One or more processors 602 may be configured to send a coupling message via transceiver 614 to the initiating UE in each ranging session, indicating that the ranging sessions should be coupled and that UE 600 may initiate a coupled ranging session, or, if UE 600 is the initiating UE, to receive a coupling message from another UE. The coupling message may include an indication of whether the location of the UE is known, so that the UE can act as a positioning anchor. One or more processors 602 may be further configured to measure one or more power characteristics of the ranging signal broadcast by the initiating UE in each ranging session, such as signal strength characteristics such as RSPR. The signal strength characteristics determined by one or more processors 602 may be the average or other combination of the measured power characteristics of multiple ranging sessions. The coupling message may provide an indication of the signal strength characteristics of the ranging signal from the initiating UE.One or more processors 602 may be further configured to receive a response message from the initiating UE via transceiver 614 indicating that the initiating UE approves of joining the ranging session and that UE 600 will initiate the combined ranging session. One or more processors 602 may be configured to initiate a combined ranging session, for example, by sending an initial pre-PRS message including all participating UEs from the independent ranging session. One or more processors 602 may be further configured to select the initiating UE of a combined ranging session if multiple UEs send joining messages to UE 600, the selection may be based on whether or not it can serve as an anchor point for positioning and on signal strength characteristics. One or more processors 602 may be further configured to send a response message via transceiver 614 to other UEs indicating that UE 600 approves of joining the ranging session and that the other UEs are selected to initiate the combined ranging session. One or more processors 602 may be further configured to send or receive indications of the availability of a coupled ranging session via transceiver 614 in possibility messages (such as message 201 in Figure 2).

[0083] The medium 620 and / or memory 604, when implemented by one or more processors 602, may include a session isolation module 632 that configures one or more processors 602 to determine whether a combined ranging session should be isolated. One or more processors 602 can be configured to determine the number of ranging signals broadcast by one or more UEs that are not received by one or more UEs in a combined ranging session, and whether that number is greater than a threshold. One or more processors 602 can be configured to send an isolation message via transceiver 614 to the previously initiating UEs indicating that the combined ranging session is ending and that the UE should start an independent ranging session. If UE 600 is one of the original initiating UEs, one or more processors 602 can be further configured to receive a message via transceiver 614 indicating that the combined ranging session is ending and that UE 600 should start an independent ranging session.

[0084] The methods described herein can be implemented by various means depending on the application. For example, these methods can be implemented in hardware, firmware, software, or any combination thereof. In the case of hardware embodiments, one or more processors 602 may be implemented as one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, electronic devices, other electronic units designed to perform the functions described herein, or a combination thereof. One or more processors 602 may be a general-purpose computer operating as a dedicated computer programmed to perform the techniques disclosed herein, when programmed to perform specific operations in accordance with instructions from program software as described herein.

[0085] In the case of implementation by firmware and / or software, the method may be implemented using modules (e.g., procedures, functions, etc.) that perform the functions described herein. Any machine-readable medium that tangibly embodies instructions may be used when implementing the method described herein. For example, software code may be stored in a non-temporary computer-readable medium 620 or memory 604 connected to one or more processors 602, and may be executed by one or more processors 602. Memory may be implemented within one or more processors, or outside of one or more processors. As used herein, the term “memory” means any type of long-term memory, short-term memory, volatile memory, non-volatile memory, or other memory, and should not be limited to any particular type of memory or any particular number of memories, or any particular type of medium in which memory is stored.

[0086] When implemented in firmware and / or software, the functionality may be stored as one or more instructions or program code 608 in a non-temporary computer-readable medium such as medium 620 and / or memory 604. Examples include computer-readable medium encoded using data structures and computer-readable medium encoded using computer program 608. For example, the non-temporary computer-readable medium storing program code 608 may contain program code 608 for assisting in the joining of multiple independent ranging sessions into a single combined ranging session in a manner compatible with the disclosed embodiments. The non-temporary computer-readable medium 620 includes a physical computer storage medium. The storage medium may be any available medium that can be accessed by a computer. Such non-temporary computer-readable media may include, but are not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other media that can be used to store desired program code 608 in the form of instructions or data structures and that can be accessed by a computer. As used herein, disks and discs include compact discs (CDs), laser discs, optical discs, digital multipurpose discs (DVDs), floppy disks, and Blu-ray® discs, where a disk typically reproduces data magnetically and a disc optically reproduces data using a laser. Any combination of the above should also be included within the scope of computer-readable media.

[0087] In addition to storage on the computer-readable medium 620, instructions and / or data may be provided as signals on a transmission medium included in a communication device. For example, the communication device may include a transceiver 610 having signals indicating instructions and data. The instructions and data are configured to cause one or more processors to implement the functions outlined in the claims. That is, the communication device includes a transmission medium having signals indicating information for performing the disclosed functions.

[0088] Memory 604 may represent any data storage mechanism. Memory 604 may include, for example, primary memory and / or secondary memory. Primary memory may include, for example, random access memory, read-only memory, etc. In this example, it is shown as separate from one or more processors 602, but it should be understood that all or part of the primary memory may be provided within one or more processors 602, or may be in the same location as / combined with them in some other way. Secondary memory may include, for example, memory of the same or similar type as primary memory, and / or one or more data storage devices or systems, such as disk drives, optical disk drives, tape drives, solid-state memory drives, etc.

[0089] In some embodiments, the secondary memory may be operationally receptive to a non-temporary computer-readable medium 620, or may be configured to otherwise bind to the non-temporary computer-readable medium 620. Thus, in some exemplary embodiments, the methods and / or apparatus presented herein may take the form of a computer-readable medium 620, in whole or in part, which may store computer-implementable code 608, and which, when executed by one or more processors 602, may be effectively enabled to perform all or part of the exemplary operations described herein. The computer-readable medium 620 may be part of the memory 604.

[0090] Figure 7 is a flowchart 700 illustrating a method for measuring the distance between UEs, which is performed by a first UE such as UEA 310A.

[0091] In block 702, the first UE receives an initial message from multiple UEs to initiate separate ranging sessions, as discussed in stages 1A and 1B of Figure 5. Means for receiving the initial message from multiple UEs to initiate separate ranging sessions may include, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a pre-PRS message module 622.

[0092] In block 704, the first UE sends a message to multiple UEs to combine separate ranging sessions, indicating that the first UE will initiate a combined ranging session, as discussed in step 3A of Figure 5. The first UE and the multiple UEs may each be, for example, a vehicle-based UE, a pedestrian-based UE, or a roadside unit. Means for sending a message to multiple UEs to combine separate ranging sessions, indicating that the first UE will initiate a combined ranging session, may include, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a session combining module 630.

[0093] In block 706, the first UE conducts a coupled ranging session with multiple UEs, as discussed in step 6 of Figure 5. Means for conducting a coupled ranging session with multiple UEs may include, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a pre-PRS message module 622, a PRS module 624, a post-PRS message module 626, and a ranging / positioning module 628.

[0094] In one embodiment, the first UE can determine that separate ranging sessions are simultaneous before sending a message to multiple UEs to combine the separate ranging sessions, as discussed in step 2A of Figure 5, for example. Means for determining that separate ranging sessions are simultaneous before sending a message to multiple UEs to combine the separate ranging sessions may include, for example, a transceiver 614 and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a session combining module 630.

[0095] In one embodiment, the first UE may determine that a plurality of UEs have started separate ranging sessions more than a predetermined number of times before sending a message to the plurality of UEs to combine separate ranging sessions, as discussed in step 2A of Figure 5, for example. Means for determining that a plurality of UEs have started separate ranging sessions more than a predetermined number of times before sending a message to the plurality of UEs to combine separate ranging sessions may include, for example, a transceiver 614 and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a session combining module 630.

[0096] In one embodiment, the first UE can send an initial message to the multiple UEs to initiate a coupled ranging session, for example, as discussed in step 6 of Figure 5. Means for sending an initial message to the multiple UEs to initiate a coupled ranging session may include, for example, a transceiver 614 and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a pre-PRS message module 622. For example, before sending an initial message to the multiple UEs to initiate a coupled ranging session, the first UE can receive response messages from the multiple UEs indicating that each of the multiple UEs acknowledges that the first UE will initiate a coupled ranging session, for example, as discussed in step 5 of Figure 5. Means for receiving response messages from multiple UEs indicating that each of the multiple UEs acknowledges that the first UE will initiate a coupled ranging session before sending an initial message to the multiple UEs to initiate a coupled ranging session may include, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a session coupling module 630.

[0097] In another embodiment, the first UE can conduct a coupled ranging session with multiple UEs, including multiple UEs and a second UE, by receiving an initial message from the second UE to initiate a coupled ranging session with multiple UEs, including multiple UEs and a second UE, as discussed in steps 3A, 3B, 4A, 4B, 5, and 6 of Figure 5. The means for receiving the initial message from the second UE to initiate a coupled ranging session with multiple UEs, including multiple UEs and a second UE, may be, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a pre-PRS message module 622.

[0098] In one embodiment, a message to multiple UEs for combining separate ranging sessions, indicating that the first UE will initiate a combined ranging session, further indicates that the first UE will become a positioning anchor, as discussed in stages 3A and 6 of Figure 5, for example, and the combined ranging session with multiple UEs includes a combined positioning session that uses the first UE as a positioning anchor.

[0099] In one embodiment, the first UE can determine the signal strength characteristics of the ranging signal in separate ranging sessions initiated by multiple UEs, as discussed in stages 2A and 3A of Figure 5, and messages to multiple UEs for combining the separate ranging sessions further indicate the signal strength characteristics of the ranging signal in the separate ranging sessions. Means for determining the signal strength characteristics of the ranging signal in separate ranging sessions initiated by multiple UEs may be, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a session combining module 630.

[0100] A combined ranging session includes all UEs participating in separate ranging sessions, including a first UE, a plurality of UEs, and a plurality of response UEs, as discussed in step 6, for example. In some embodiments, the first UE can determine, for example, as discussed in step 7A of Figure 5, that ranging signals broadcast in a plurality of combined ranging sessions are not received by another UE more than a predetermined threshold number of times. The first UE can send a second message to the plurality of UEs to separate the combined ranging session, indicating that the plurality of UEs will initiate separate ranging sessions, as discussed in step 8 of Figure 5. Means for determining that a distance measurement signal broadcast in multiple combined distance measurement sessions is not received by another UE beyond a predetermined threshold number of times, and means for sending a second message to multiple UEs to isolate the combined distance measurement session, indicating that the multiple UEs will start separate distance measurement sessions, may be, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a session isolation module 632.

[0101] In one embodiment, the first UE can receive potential messages from multiple UEs indicating the availability of joining ranging sessions, as discussed, for example, by message 201 in Figure 2 and step 2A in Figure 5, and messages sent to multiple UEs to join separate ranging sessions respond, at least partially, to potential messages indicating the availability of joining ranging sessions. Means for receiving potential messages indicating the availability of joining ranging sessions from multiple UEs, messages sent to multiple UEs to join separate ranging sessions respond, at least partially, to potential messages indicating the availability of joining ranging sessions, may include, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a session joining module 630.

[0102] Figure 8 is a flowchart 800 illustrating a method for measuring the distance between UEs, which is performed by a first UE such as UE1 302.

[0103] In block 802, the first UE sends an initial message to the second UE to initiate a first ranging session, as discussed in step 1A of Figure 5. Means for sending the initial message to initiate the first ranging session to the second UE may include, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a pre-PRS message module 622.

[0104] In block 804, the first UE receives a message from the second UE to combine the first ranging session with a second ranging session initiated by the third UE, indicating that the second UE will initiate a combined ranging session, as discussed in step 3A of Figure 5. The first UE, the second UE, and the third UE may each be, for example, a vehicle-based UE, a pedestrian-based UE, or a roadside unit. Means for receiving a message from the second UE to combine the first ranging session with a second ranging session initiated by the third UE, indicating that the second UE will initiate a combined ranging session, may include, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a session combining module 630.

[0105] In block 806, the first UE conducts a coupled ranging session with the second UE, as discussed in step 6 of Figure 5. Means for conducting the coupled ranging session with the second UE may include, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a pre-PRS message module 622, a PRS module 624, a post-PRS message module 626, and a ranging / positioning module 628.

[0106] In one embodiment, the second UE can determine that the first and second ranging sessions are simultaneous before sending a message to combine the first and second ranging sessions, for example, as discussed in step 2A of Figure 5. In another embodiment, the second UE can determine that the first and third UEs have started separate ranging sessions more than a predetermined number of times before sending a message to combine the first and second ranging sessions, for example, as discussed in step 2A of Figure 5.

[0107] In one embodiment, the first UE may receive an initial message from the second UE to initiate a coupled ranging session, for example, as discussed in step 6 of Figure 5. Means for receiving the initial message from the second UE to initiate a coupled ranging session may include, for example, a transceiver 614 and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in the memory 604 and / or medium 620, such as a pre-PRS message module 622. For example, the first UE may send a response message to the second UE indicating that the second UE is initiating a coupled ranging session, for example, as discussed in step 5 of Figure 5. Means for sending a response message to the second UE indicating that the second UE is initiating a coupled ranging session may include, for example, a transceiver 614 and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in the memory 604 and / or medium 620, such as a session coupling module 630. For example, an initial message can be sent by broadcasting an initial message to the second and fourth UEs to initiate the first ranging session, and the first UE can receive a second message from the fourth UE to combine the first ranging session with the second ranging session initiated by the third UE, indicating that the fourth UE will initiate a combined ranging session, as discussed in step 3B of Figure 5, for example. The first UE can send a response message to the second UE indicating that the second UE will initiate a combined ranging session, as discussed in step 5 of Figure 5, for example. The first UE can receive an initial message from the second UE to initiate a combined ranging session including the second, third, and fourth UEs, as discussed in step 6 of Figure 5, for example.Means for receiving a second message from the fourth UE to combine the first ranging session with a second ranging session initiated by the third UE, indicating that the fourth UE will initiate a combined ranging session, may include, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a session combining module 630. Means for receiving an initial message from the second UE to initiate a combined ranging session including the second UE, the third UE, and the fourth UE may include, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a pre-PRS message module 622. In one example, a message from the second UE may indicate that the second UE will be the positioning anchor, and a second message from the fourth UE may not indicate that the fourth UE will be the positioning anchor, and a response message to the second UE indicating that the second UE will initiate a coupled ranging session is sent in response to the second UE indicating that it will be the positioning anchor, and the coupled ranging session includes a coupled positioning session using the second UE as the positioning anchor, as discussed in step 4A of Figure 5, for example. In another example, a message from the second UE may further indicate a first value of the signal intensity characteristics of the distance measurement signals in the first and second distance measurement sessions as measured by the second UE, a second message from the fourth UE may indicate a second value of the signal intensity characteristics of the distance measurement signals in the first and second distance measurement sessions as measured by the fourth UE, and a response message to the second UE indicating that the second UE will initiate a combined distance measurement session is sent in response to the first value of the signal intensity characteristics being greater than the second value of the signal intensity characteristics, as discussed in step 4A of Figure 5, for example.

[0108] A combined ranging session includes all UEs participating in the first ranging session and the second ranging session, including a first UE, a second UE, a third UE, and a plurality of response UEs, as discussed in step 6, for example. In some embodiments, the first UE may receive a second message from the second UE to isolate the combined ranging session, indicating that the first UE will initiate a ranging session in response to the second UE determining that the ranging signal broadcast in the plurality of combined ranging sessions has not been received by another UE more than a predetermined threshold number of times, as discussed in step 7A of Figure 5, for example. Means for receiving a second message from the second UE to isolate a coupled ranging session, indicating that the first UE will start a ranging session in response to the second UE determining that the ranging signal broadcast in multiple coupled ranging sessions has not been received by another UE more than a predetermined threshold number of times, may include, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a session isolation module 632.

[0109] In one embodiment, the first UE may send a possibility message indicating the availability of joining a ranging session, as shown, for example, by message 201 in Figure 2 and discussed in step 2A of Figure 5. Means for sending a possibility message indicating the availability of joining a ranging session may be, for example, a transceiver 614, and one or more processors 602 that have dedicated hardware or implement executable code or software instructions in memory 604 and / or medium 620, such as a session joining module 630.

[0110] Throughout this specification, any reference to “an example,” “a certain example,” “some examples,” or “exemplary embodiments” means that any particular feature, structure, or characteristic described in relation to a feature and / or example may be included in at least one feature and / or example of the claimed subject matter. Therefore, occurrences of phrases such as “in an example,” “a certain example,” “in a particular example,” or “in some embodiments” or other similar phrases in various places throughout this specification do not necessarily all refer to the same feature, example, and / or limitation. Furthermore, any particular feature, structure, or characteristic may be combined in one or more examples and / or features.

[0111] Some portions of the detailed descriptions contained herein are presented with respect to algorithms or symbolic representations of operations for binary digital signals stored in the memory of a particular apparatus or dedicated computing device or platform. In the context of this particular specification, the term "particular apparatus, etc." includes a general-purpose computer after it has been programmed to perform a particular operation in accordance with instructions from program software. The description or symbolic representation of an algorithm is an example of a technique used by a person skilled in the art of signal processing or related technology to communicate the nature of their work to others skilled in the art. In this specification, an algorithm is also generally considered to be a self-consistent set of operations or similar signal operations that produce a desired result. In this context, operations or operations involve the physical handling of a physical quantity. Typically, but not always, such quantities may take the form of electrical or magnetic signals that can be stored, transferred, combined, compared, or otherwise manipulated. It has been found that it is sometimes convenient to refer to such signals as bits, data, values, elements, symbols, characters, terms, digits, numerical values, etc., mainly because they are common usage. However, it should be understood that all of these terms or similar terms should be associated with the appropriate physical quantities and are merely convenient designations. Unless otherwise specified, as will be apparent from the descriptions herein, any use of terms such as “processing,” “calculating,” “calculating,” and “determining” throughout this specification should be understood to refer to actions or processes of specific devices, such as a dedicated computer, dedicated computing device, or similar dedicated electronic computing device. Therefore, in the context of this specification, a dedicated computer or similar dedicated electronic computing device is capable of manipulating or converting signals that are typically represented as physical electronic or magnetic quantities within the memory, registers, or other information storage devices, transmitting devices, or display devices of the dedicated computer or similar dedicated electronic computing device.

[0112] The detailed description above includes numerous specific details to give a complete understanding of the claimed subject matter. However, it will be understood by those skilled in the art that the claimed subject matter can be practiced without these specific details. In other cases, methods and apparatus that would be known to those skilled in the art are not described in detail so as not to obscure the claimed subject matter.

[0113] As used herein, the terms “and,” “or,” and “and / or” may have a variety of meanings, which are also expected to depend at least partially on the context in which such terms are used. Typically, when “or” is used to relate an enumeration such as A, B, or C, it is intended to mean A, B, and C in an inclusive sense, as well as A, B, or C in an exclusive sense. In addition, as used herein, the term “one or more” may be used to describe any singular feature, structure, or characteristic, or to describe multiple features, structures, or characteristics, or any other combination of features, structures, or characteristics. However, it should be noted that this is merely an illustrative example, and the claimed subject matter is not limited to this example.

[0114] While exemplary features and those currently considered to be exemplary are illustrated and described, it will be understood by those skilled in the art that various other modifications may be made and equivalents may be substituted without departing from the claimed subject matter. In addition, many modifications may be made to adapt specific situations to the teachings of the claimed subject matter without departing from the central concepts described herein.

[0115] Implementation examples are described in the following numbered sections.

[0116] 1. A method for measuring the distance between UEs performed by a first user device (UE), The steps include receiving initial messages from multiple UEs to start separate distance measurement sessions, The process involves sending a message to multiple UEs to merge separate ranging sessions, indicating that the first UE will initiate a combined ranging session, The steps include conducting a combined distance measurement session with multiple UEs and Methods that include...

[0117] 2. The method according to item 1, further comprising the step of determining that separate ranging sessions are simultaneous before sending a message to multiple UEs to combine separate ranging sessions.

[0118] 3. The method according to item 1 or 2, further comprising the step of determining whether multiple UEs have initiated separate ranging sessions more than a predetermined number of times before sending a message to multiple UEs to combine separate ranging sessions.

[0119] 4. The method according to any one of items 1 to 3, further comprising the step of sending an initial message to multiple UEs to initiate a combined ranging session.

[0120] 5. The method of Section 4, further comprising the step of receiving response messages from the multiple UEs indicating that each of the multiple UEs acknowledges that the first UE will initiate a combined ranging session, before sending an initial message to the multiple UEs to initiate a combined ranging session.

[0121] 6. The step of conducting a combined distance measurement session with multiple UEs is: The method according to any one of items 1 to 5, comprising the step of receiving an initial message from the second UE to initiate a coupled ranging session with multiple UEs, including multiple UEs and a second UE.

[0122] 7. The method according to any one of items 1 to 6, wherein a message to multiple UEs for combining separate ranging sessions indicates that the first UE will initiate a combined ranging session, further indicating that the first UE will become a positioning anchor, and the combined ranging session with multiple UEs includes a combined positioning session that uses the first UE as a positioning anchor.

[0123] 8. The process further includes the step of determining the signal intensity characteristics of the ranging signal in separate ranging sessions initiated by multiple UEs, Messages to multiple UEs for combining separate distance measurement sessions, as described in any one of items 1 to 7, further describe the signal intensity characteristics of the distance measurement signals in the separate distance measurement sessions.

[0124] 9. A combined ranging session is the method described in any one of items 1 to 8, including a first UE, multiple UEs and multiple response UEs, and all UEs participating in separate ranging sessions.

[0125] 10. The method is, The steps include determining that the distance measurement signal broadcast in multiple combined distance measurement sessions is not received by another UE more than a predetermined threshold number of times, The steps include sending a second message to multiple UEs to separate the combined ranging session, indicating that multiple UEs will start separate ranging sessions, and The method described in paragraph 9, further including the method described in paragraph 9.

[0126] 11. The method according to any one of items 1 to 10, further comprising the step of receiving potential messages from multiple UEs indicating the availability of joining ranging sessions, wherein messages sent to multiple UEs to join separate ranging sessions are at least partially in response to potential messages indicating the availability of joining ranging sessions.

[0127] 12. The method according to any one of sub-sub

[0128] 13. A first UE configured for distance measurement between user equipment (UEs), A wireless transceiver configured to communicate wirelessly with entities in a wireless network, At least one memory, It comprises a wireless transceiver and at least one processor coupled to at least one memory, wherein the at least one processor is Receiving initial messages from multiple UEs via a wireless transceiver to initiate separate ranging sessions, Sending a message to multiple UEs via a wireless transceiver to merge separate ranging sessions, indicating that the first UE will initiate a combined ranging session, Conduct a combined distance measurement session with multiple UEs. A first UE is configured to perform the following actions.

[0129] 14. The first UE as described in Section 13, further configured to determine that separate ranging sessions are concurrent before sending a message to multiple UEs for combining separate ranging sessions.

[0130] 15. The first UE as described in Section 13 or 14, further configured such that at least one processor determines whether the multiple UEs have initiated separate ranging sessions more than a predetermined number of times before sending a message to the multiple UEs for combining separate ranging sessions.

[0131] 16. The first UE described in any one of sections 13 to 15, wherein at least one processor is further configured to send an initial message to multiple UEs for initiating a coupled ranging session.

[0132] 17. The first UE as described in Section 16, further configured to receive response messages from the multiple UEs indicating that each of the multiple UEs acknowledges that the first UE will initiate a combined ranging session, before sending an initial message to the multiple UEs to initiate a combined ranging session.

[0133] 18. At least one processor, The first UE, as described in any one of sections 13 to 17, is configured to conduct a coupled ranging session with multiple UEs, including multiple UEs and a second UE, by being configured to receive an initial message from the second UE via a wireless transceiver to initiate a coupled ranging session with multiple UEs, including multiple UEs and a second UE.

[0134] 19. A message to multiple UEs for combining separate ranging sessions, indicating that the first UE will initiate a combined ranging session, further indicating that the first UE will become a positioning anchor, and the combined ranging session with multiple UEs includes a combined positioning session that uses the first UE as a positioning anchor, as described in any one of sections 13 to 18.

[0135] 20. At least one processor, It is further configured to determine the signal intensity characteristics of the ranging signal in separate ranging sessions initiated by multiple UEs, Messages to multiple UEs for combining separate distance measurement sessions are provided to the first UE as described in any one of sections 13 to 19, further indicating the signal intensity characteristics of the distance measurement signals in the separate distance measurement sessions.

[0136] 21. A combined ranging session includes the first UE, multiple UEs, and multiple response UEs, including all UEs participating in separate ranging sessions, as described in any one of sections 13 to 20.

[0137] 22. At least one processor, In multiple combined ranging sessions, it is determined that the ranging signal broadcast is not received by another UE beyond a predetermined threshold number of times, Sending a second message to multiple UEs via a wireless transceiver to separate the combined ranging session, indicating that multiple UEs will start separate ranging sessions. The first UE described in Section 21 is further configured to perform the following:

[0138] 23. At least one processor is further configured to receive potential messages from multiple UEs via a wireless transceiver indicating the availability of joining ranging sessions, and the messages sent to the multiple UEs to join separate ranging sessions are at least partially in response to potential messages indicating the availability of joining ranging sessions, as described in any one of paragraphs 13 to 22.

[0139] 24. The first UE and each of the multiple UEs are one of a vehicle-based UE, a pedestrian-based UE, or a roadside unit, as described in any one of the paragraphs 13 to 23.

[0140] 25. A first UE configured for measuring distance between user equipment (UEs), A means for receiving initial messages from multiple UEs to start separate distance measurement sessions, A means for sending a message to multiple UEs to merge separate ranging sessions, indicating that the first UE will initiate a combined ranging session, A means for conducting a combined distance measurement session with multiple UEs and A first UE equipped with [a certain feature].

[0141] 26. The first UE as described in Section 25, further comprising means for determining whether separate ranging sessions are simultaneous before sending a message to multiple UEs for combining separate ranging sessions.

[0142] 27. The first UE as described in Section 25 or 26, further comprising means for determining whether multiple UEs initiate separate ranging sessions more than a predetermined number of times before sending a message to multiple UEs for combining separate ranging sessions.

[0143] 28. The first UE described in any one of paragraphs 25 to 27, further comprising means for sending an initial message to multiple UEs for initiating a combined ranging session.

[0144] 29. The first UE as described in Section 28, further comprising means for receiving response messages from the multiple UEs indicating that each of the multiple UEs acknowledges that the first UE will initiate a combined ranging session, before sending an initial message to the multiple UEs to initiate a combined ranging session.

[0145] 30. Means for conducting a combined distance measurement session with multiple UEs are: The first UE as described in any one of paragraphs 25 to 29, including means for receiving an initial message from the second UE to initiate a coupled ranging session with multiple UEs, including multiple UEs and the second UE.

[0146] 31. A message to multiple UEs for combining separate ranging sessions, indicating that the first UE will initiate a combined ranging session, further indicating that the first UE will become a positioning anchor, and the combined ranging session with multiple UEs includes a combined positioning session that uses the first UE as a positioning anchor, as described in any one of sections 25 to 30.

[0147] 32. Further comprising means for determining the signal intensity characteristics of distance measurement signals in separate distance measurement sessions initiated by multiple UEs, Messages to multiple UEs for combining separate distance measurement sessions are provided to the first UE as described in any one of sections 25 to 31, further indicating the signal intensity characteristics of the distance measurement signals in the separate distance measurement sessions.

[0148] 33. A combined ranging session includes the first UE, multiple UEs, and multiple response UEs, including all UEs participating in separate ranging sessions, as described in any one of sections 25 to 32.

[0149] 34. Means for determining that a distance measurement signal broadcast in multiple combined distance measurement sessions is not received by another UE beyond a predetermined threshold number of times, A means for sending a second message to multiple UEs to separate the combined ranging session, indicating that multiple UEs will start separate ranging sessions, and The first UE as described in paragraph 33, further comprising:

[0150] 35. The first UE as described in any one of paragraphs 25 to 34, further comprising means for receiving potential messages from multiple UEs indicating the availability of joining ranging sessions, wherein messages sent to multiple UEs to join separate ranging sessions are at least partially in response to potential messages indicating the availability of joining ranging sessions.

[0151] 36. The first UE and each of the multiple UEs are one of a vehicle-based UE, a pedestrian-based UE, or a roadside unit, as described in any one of subsections 25 to 35.

[0152] 37. A non-temporary storage medium containing program code stored thereon, wherein the program code is operable to configure at least one processor in a first user device (UE) for distance measurement between UEs, and the program code Receiving initial messages from multiple UEs to start separate distance measurement sessions, Sending a message to multiple UEs to merge separate ranging sessions, indicating that the first UE will initiate a combined ranging session, Conduct a combined distance measurement session with multiple UEs. A non-temporary storage medium containing program code, including instructions for performing a certain action.

[0153] 38. A non-temporary storage medium containing the program code described in Section 37, further comprising program code for determining whether separate ranging sessions are simultaneous before sending a message to multiple UEs for combining separate ranging sessions.

[0154] 39. A non-temporary storage medium comprising the program code described in Section 37 or 38, further comprising program code for determining whether multiple UEs initiate separate ranging sessions more than a predetermined number of times before sending a message to multiple UEs for combining separate ranging sessions.

[0155] 40. A non-temporary storage medium containing the program code described in any one of paragraphs 37 to 39, further comprising program code for sending an initial message to multiple UEs to initiate a coupled ranging session.

[0156] 41. A non-temporary storage medium containing the program code described in Section 40, further comprising program code for receiving response messages from multiple UEs indicating that each of the multiple UEs acknowledges that the first UE will initiate a combined ranging session, before sending an initial message to the multiple UEs to initiate the combined ranging session.

[0157] 42. The program code for conducting a coupled distance measurement session with multiple UEs is: A non-temporary storage medium containing program code described in any one of paragraphs 37 to 41, including program code for receiving an initial message from a second UE to initiate a coupled ranging session with multiple UEs, including multiple UEs and a second UE.

[0158] 43. A non-temporary storage medium containing program code as described in any one of paragraphs 37 to 42, which includes a message to multiple UEs for combining separate ranging sessions, indicating that the first UE will initiate a combined ranging session, further indicating that the first UE will become a positioning anchor, and the combined ranging session with multiple UEs includes a combined positioning session that uses the first UE as a positioning anchor.

[0159] 44. Further comprising program code for determining the signal strength characteristics of distance measurement signals in separate distance measurement sessions initiated by multiple UEs, A non-temporary storage medium containing program code described in any one of sections 37 to 43, which further describes the signal intensity characteristics of the distance measurement signals in the separate distance measurement sessions, for messages to multiple UEs to combine separate distance measurement sessions.

[0160] 45. A coupled ranging session is a non-temporary storage medium containing program code as described in any one of sections 37 to 44, including a first UE, multiple UEs, and multiple response UEs, and all UEs participating in separate ranging sessions.

[0161] 46. ​​Determining that the distance measurement signals broadcast in multiple combined distance measurement sessions are not received by another UE beyond a predetermined threshold number of times, Sending a second message to multiple UEs to separate the combined ranging session, indicating that multiple UEs will start separate ranging sessions, and A non-temporary storage medium containing the program code described in paragraph 45, further comprising program code for performing the following.

[0162] 47. A non-temporary storage medium comprising program code for receiving potential messages from multiple UEs indicating the availability of joining ranging sessions, wherein messages sent to multiple UEs to join separate ranging sessions include, at least in part, the program code described in any one of paragraphs 37 to 46, in response to potential messages indicating the availability of joining ranging sessions.

[0163] 48. A non-temporary storage medium containing program code as described in any one of paragraphs 37 to 47, wherein each of the first UE and multiple UEs is one of a vehicle-based UE, a pedestrian-based UE, or a roadside unit.

[0164] 49. A method for measuring the distance between UEs performed by a first user device (UE), The steps include sending an initial message to the second UE to start the first ranging session, The steps include receiving a message from the second UE indicating that the second UE will initiate a combined ranging session, to combine the first ranging session with the second ranging session initiated by the third UE, The steps include conducting a coupled distance measurement session with the second UE and Methods that include...

[0165] 50. The method according to paragraph 49, wherein the second UE determines that the first and second ranging sessions are simultaneous before sending a message to combine the first and second ranging sessions.

[0166] 51. The method according to paragraph 49 or 50, wherein the second UE determines that the first UE and the third UE have started separate ranging sessions more than a predetermined number of times before sending a message to combine the first ranging session and the second ranging session.

[0167] 52. The method according to any one of sections 49 to 51, further comprising the step of receiving an initial message from a second UE to initiate a coupled ranging session.

[0168] 53. The method of paragraph 52, further comprising the step of sending a response message to the second UE indicating that the second UE will initiate a coupled ranging session.

[0169] 54. The step of sending an initial message includes the step of broadcasting an initial message to the second and fourth UEs to initiate the first ranging session, and the method is: The steps include receiving a second message from the fourth UE to combine the first ranging session with the second ranging session initiated by the third UE, indicating that the fourth UE will initiate a combined ranging session, The steps include sending a response message to the second UE indicating that the second UE will initiate a combined ranging session, The steps include receiving an initial message from the second UE to start the combined ranging session, and It further includes, A combined ranging session is the method described in Section 53, including a second UE, a third UE, and a fourth UE.

[0170] 55. The method of paragraph 54, wherein a message from the second UE indicates that the second UE will be the positioning anchor, and a second message from the fourth UE does not indicate that the fourth UE will be the positioning anchor, and a response message to the second UE indicating that the second UE will initiate a coupled ranging session, in response to the second UE indicating that the second UE will be the positioning anchor, and the coupled ranging session includes a coupled positioning session using the second UE as the positioning anchor.

[0171] 56. The method according to paragraph 54, wherein a message from the second UE further indicates a first value of the signal intensity characteristics of the distance measuring signals in the first and second distance measuring sessions as measured by the second UE, and a second message from the fourth UE indicates a second value of the signal intensity characteristics of the distance measuring signals in the first and second distance measuring sessions as measured by the fourth UE, and the step of sending a response message to the second UE indicating that the second UE will initiate a combined distance measuring session is in response to the first value of the signal intensity characteristics being greater than the second value of the signal intensity characteristics.

[0172] 57. The method according to any one of paragraphs 49 to 56, wherein a combined ranging session includes all UEs participating in the first ranging session and the second ranging session, including a first UE, a second UE, a third UE, and a plurality of response UEs.

[0173] 58. The method is, The method according to paragraph 57, further comprising the step of receiving a second message from the second UE for isolating a combined ranging session, indicating that the first UE will initiate a ranging session in response to the second UE determining that the ranging signals broadcast in multiple combined ranging sessions will not be received by another UE more than a predetermined threshold number of times.

[0174] 59. The method according to any one of paragraphs 49 to 58, further comprising the step of sending a possibility message indicating the availability of joining ranging sessions.

[0175] 60. The method according to any one of paragraphs 49 to 59, wherein the first UE, the second UE, and the third UE are each one of a vehicle-based UE, a pedestrian-based UE, or a roadside machine.

[0176] 61. A first UE configured for measuring distance between user equipment (UEs), A wireless transceiver configured to communicate wirelessly with entities in a wireless network, At least one memory, It comprises a wireless transceiver and at least one processor coupled to at least one memory, wherein the at least one processor is Sending an initial message to the second UE via the wireless transceiver to initiate the first ranging session, The second UE receives a message via a wireless transceiver indicating that the second UE will initiate a combined ranging session, and the first ranging session is to be combined with the second ranging session initiated by the third UE. To conduct a coupled distance measurement session with the second UE A first UE is configured to perform the following actions.

[0177] 62. The first UE as described in paragraph 61, which determines that the first and second ranging sessions are simultaneous before sending a message to combine the first and second ranging sessions.

[0178] 63. The first UE as described in paragraph 61 or 62, wherein the second UE determines that the first UE and the third UE have started separate ranging sessions more than a predetermined number of times before sending a message to combine the first ranging session and the second ranging session.

[0179] 64. The first UE as described in any one of sections 61 to 63, further configured to receive an initial message from the second UE for initiating a coupled ranging session, with at least one processor.

[0180] 65. The first UE as described in Section 64, further configured to send a response message to the second UE indicating that the second UE will initiate a coupled ranging session, with at least one processor configured to do so.

[0181] 66. At least one processor is configured to send an initial message by being configured to broadcast an initial message to the second and fourth UEs to initiate a first ranging session, and at least one processor is configured to send an initial message. The fourth UE receives a second message via a wireless transceiver to combine the first ranging session with the second ranging session initiated by the third UE, indicating that the fourth UE will initiate a combined ranging session. Sending a response message to the second UE via the wireless transceiver indicating that the second UE will initiate a coupled ranging session, The initial message to initiate the coupled ranging session is received from the second UE via the wireless transceiver. It is further configured to do the following: The combined ranging session includes the first UE as described in Section 65, which also includes the second UE, the third UE, and the fourth UE.

[0182] 67. A message from the second UE indicates that the second UE will be a positioning anchor, and a second message from the fourth UE does not indicate that the fourth UE will be a positioning anchor, and at least one processor is configured to send a response message to the second UE indicating that the second UE will initiate a coupled ranging session in response to the second UE indicating that the second UE will be a positioning anchor, the coupled ranging session includes a coupled positioning session using the second UE as a positioning anchor, as described in Section 66.

[0183] 68. The first UE as described in Section 66, wherein a message from the second UE further indicates a first value of the signal intensity characteristics of the distance measuring signals in the first and second distance measuring sessions as measured by the second UE, and a second message from the fourth UE indicates a second value of the signal intensity characteristics of the distance measuring signals in the first and second distance measuring sessions as measured by the fourth UE, and at least one processor is configured to send a response message to the second UE indicating that the second UE will initiate a coupled distance measuring session in response to the first value of the signal intensity characteristics being greater than the second value of the signal intensity characteristics.

[0184] 69. A combined ranging session includes the first UE, the second UE, the third UE, and multiple response UEs, including all UEs participating in the first ranging session and the second ranging session, as described in any one of paragraphs 61 to 68.

[0185] 70. At least one processor, The first UE as described in Section 69, further configured to receive a second message from the second UE for isolating coupled ranging sessions, indicating that the first UE will initiate a ranging session in response to the second UE determining, via a wireless transceiver, that ranging signals broadcast in multiple coupled ranging sessions will not be received by another UE more than a predetermined threshold number of times.

[0186] 71. The first UE as described in any one of the paragraphs 61 to 70, further configured to send potential messages via a wireless transceiver indicating the availability of coupling of ranging sessions.

[0187] 72. The first UE, the second UE, and the third UE are each one of a vehicle-based UE, a pedestrian-based UE, or a roadside unit, as described in any one of paragraphs 61 to 71.

[0188] 73. A first UE configured for distance measurement between user equipment (UEs), A means for sending an initial message to the second UE to initiate the first ranging session, A means for receiving a message from the second UE indicating that the second UE will initiate a combined ranging session, for combining the first ranging session with the second ranging session initiated by the third UE, Means for conducting a coupled ranging session with the second UE and A first UE equipped with [a certain feature].

[0189] 74. The first UE, as described in Section 73, determines that the first and second ranging sessions are simultaneous before sending a message to combine the first and second ranging sessions.

[0190] 75. The first UE as described in paragraph 73 or 74, which determines that the first UE and the third UE have started separate ranging sessions more than a predetermined number of times before sending a message to combine the first ranging session and the second ranging session.

[0191] 76. The first UE as described in any one of paragraphs 73 to 75, further comprising means for receiving an initial message from the second UE for initiating a coupled ranging session.

[0192] 77. The first UE as described in paragraph 76, further comprising means for sending a response message to the second UE indicating that the second UE will initiate a coupled ranging session.

[0193] 78. Means for sending an initial message include broadcasting an initial message to the second UE and the fourth UE to initiate a first ranging session, the first UE, A means for receiving a second message from the fourth UE to combine the first ranging session with the second ranging session initiated by the third UE, indicating that the fourth UE will initiate a combined ranging session, A means for sending a response message to the second UE indicating that the second UE will initiate a coupled ranging session, A means for receiving an initial message from the second UE to start a coupled ranging session, Equipped with, The combined ranging session includes the first UE as described in Section 77, which also includes the second UE, the third UE, and the fourth UE.

[0194] 79. Means for sending a response message to the second UE indicating that a message from the second UE will be a positioning anchor, and a second message from the fourth UE will not be a positioning anchor, and that the second UE will initiate a coupled ranging session, in response to the second UE indicating that it will be a positioning anchor, and the coupled ranging session includes a coupled positioning session using the second UE as a positioning anchor, as described in Section 78.

[0195] 80. The first UE as described in paragraph 78, wherein a message from the second UE further indicates a first value of the signal intensity characteristics of the distance measuring signals in the first and second distance measuring sessions as measured by the second UE, and a second message from the fourth UE indicates a second value of the signal intensity characteristics of the distance measuring signals in the first and second distance measuring sessions as measured by the fourth UE, and means for sending a response message to the second UE indicating that the second UE will initiate a combined distance measuring session, the first UE responding that the first value of the signal intensity characteristics is greater than the second value of the signal intensity characteristics.

[0196] 81. A combined ranging session includes the first UE, the second UE, the third UE, and multiple response UEs, including all UEs participating in the first ranging session and the second ranging session, as described in any one of paragraphs 73 to 80.

[0197] 82. The first UE according to paragraph 81, further comprising means for receiving from the second UE a second message for isolating a coupled ranging session, indicating that the first UE will initiate a ranging session in response to the second UE determining that ranging signals broadcast in a plurality of coupled ranging sessions will not be received by another UE more than a predetermined threshold number of times.

[0198] 83. The first UE described in any one of paragraphs 73 to 82, further comprising means for sending a potential message indicating the availability of joining ranging sessions.

[0199] 84. The first UE, the second UE, and the third UE are each one of a vehicle-based UE, a pedestrian-based UE, or a roadside unit, as described in any one of the paragraphs 73 to 83.

[0200] 85. A non-temporary storage medium containing program code stored thereon, wherein the program code is operable to configure at least one processor in a first user device (UE) for distance measurement between UEs, and the program code Sending an initial message to the second UE to start the first ranging session, The second UE receives a message from the second UE indicating that the second UE will initiate a combined ranging session, and the first ranging session is to be combined with the second ranging session initiated by the third UE. To conduct a coupled distance measurement session with the second UE A non-temporary storage medium containing program code, including instructions for performing a certain action.

[0201] 86. A non-temporary storage medium containing the program code described in Section 85, which determines that the first and second ranging sessions are simultaneous before sending a message to combine the first and second ranging sessions.

[0202] 87. A non-temporary storage medium containing program code as described in Section 85 or 86, wherein the second UE determines that the first UE and the third UE have started separate distance measurement sessions more than a predetermined number of times, before sending a message to combine the first distance measurement session and the second distance measurement session.

[0203] 88. A non-temporary storage medium comprising the program code described in any one of paragraphs 85 to 87, further comprising program code for receiving an initial message from a second UE for initiating a coupled ranging session.

[0204] 89. A non-temporary storage medium containing the program code described in Section 88, further comprising program code for sending a response message to the second UE indicating that the second UE will initiate a coupled ranging session.

[0205] 90. The program code for sending the initial message includes program code for broadcasting an initial message to the second and fourth UEs to initiate the first ranging session, and the non-temporary storage medium is, The fourth UE receives a second message from the fourth UE to combine the first ranging session with the second ranging session initiated by the third UE, indicating that the fourth UE will initiate a combined ranging session. Send a response message to the second UE indicating that the second UE will initiate a coupled ranging session, The initial message to start the combined ranging session is received from the second UE. Further, the program code to perform this task is provided. The combined ranging session is a non-temporary storage medium containing the program code described in Section 89, including the second UE, the third UE, and the fourth UE.

[0206] 91. A non-temporary storage medium containing the program code described in Section 90, wherein a message from the second UE indicates that the second UE will become a positioning anchor, and a second message from the fourth UE does not indicate that the fourth UE will become a positioning anchor, and the program code for sending a response message to the second UE indicating that the second UE will initiate a coupled ranging session, wherein the program code includes a coupled positioning session that uses the second UE as a positioning anchor.

[0207] 92. A non-temporary storage medium comprising the program code described in Section 90, wherein a message from the second UE further indicates a first value of the signal intensity characteristics of the distance measuring signals in the first and second distance measuring sessions as measured by the second UE, a second message from the fourth UE indicates a second value of the signal intensity characteristics of the distance measuring signals in the first and second distance measuring sessions as measured by the fourth UE, and program code for sending a response message to the second UE indicating that the second UE will initiate a combined distance measuring session, responding that the first value of the signal intensity characteristics is greater than the second value of the signal intensity characteristics.

[0208] 93. A non-temporary storage medium containing program code as described in any one of paragraphs 85 to 92, including a first UE, a second UE, a third UE, and multiple response UEs, and all UEs participating in the first and second ranging sessions.

[0209] 94. A non-temporary storage medium comprising the program code described in paragraph 93, further comprising program code for receiving a second message from the second UE for isolating a coupled ranging session, indicating that the first UE will initiate a ranging session in response to the second UE determining that ranging signals broadcast in multiple coupled ranging sessions will not be received by another UE more than a predetermined threshold number of times.

[0210] 95. A non-temporary storage medium containing the program code described in any one of paragraphs 85 to 94, further comprising program code for sending a possible message indicating the availability of joining ranging sessions.

[0211] 96. A non-temporary storage medium containing program code as described in any one of paragraphs 85 to 95, wherein the first UE, the second UE, and the third UE are each one of a vehicle-based UE, a pedestrian-based UE, or a roadside unit.

[0212] Therefore, it is intended that the claimed subject matter is not limited to the specific examples disclosed, but may also include all embodiments and their equivalents that fall within the scope of the attached claims. [Explanation of Symbols]

[0213] Stage 1A Stage 1B Stage 2A Stage 2B Stage 3A 3B stage Stage 4A Stage 4B 5 levels 6 levels 7A stage 7B stage 8 levels 9A stage 9B stage 100 Wireless Communication Systems 102 V-UE 103 Links 104 V-UE 107 links 109 links 110 Roadside Unit (RSU) 111 Wired connection 112 UE 113 V2V communication link 114 Pedestrians 115 V2V communication link 117 V2I communication links 200 Signaling Graph 201 Possibility Messages 202 Distance Measurement Session 204PRS Pre-Message 206 PRS signal 208 PRS post signal 300 Systems 302 UE1 303 Pre-PRS Message 304 UE2 305 PRS Pre-Message 310 UE 310A UEA 310B UEB 310C UEC 350 System 353 Pre-PRS Message 353-1 Pre-PRS Message 353-3 Pre-PRS Message 353-B Pre-PRS Message 353-C Pre-PRS Message 400 Visibility Map 402 lines 500 Signaling Flow 600 User Equipment (UE) 602 Processors 604 memory 605 Vehicle Interface 606 connections 607 Inertial measuring device 608 Instruction or program code 609 Satellite Positioning System (SPS) receiver 610 Wireless Wide Area Network (WWAN) Transmitter / Receiver 611 Transmitter 612 Receiver 614 Wireless Local Area Network (WLAN) Transmitter / Receiver 615 Transmitter 616 Receiver 620 Non-temporary computer-readable media 622 PRS Pre-Message Module 624 PRS Module 626 Post-PRS Message Module 628 Distance Measurement / Positioning Module 630 Session Binding Module 632 Session Isolation Module

Claims

1. A method for measuring the distance between UEs performed by a first user device (UE), The steps include receiving initial messages from multiple UEs to start separate distance measurement sessions, The steps include sending a message to the multiple UEs to combine the separate distance measurement sessions, indicating that the first UE will start a combined distance measurement session, After the sending step, there is a step of performing the coupled distance measurement session with the plurality of UEs. Methods that include...

2. The method according to claim 1, further comprising the step of determining that the separate distance measurement sessions are simultaneous before sending the message for combining the separate distance measurement sessions to the plurality of UEs.

3. The method according to claim 1, further comprising the step of determining whether the plurality of UEs initiate separate distance measurement sessions more than a predetermined number of times before sending the message for combining the separate distance measurement sessions to the plurality of UEs.

4. The steps include sending an initial message to the plurality of UEs to start the combined distance measurement session, The method according to claim 1, further comprising the step of receiving response messages from the plurality of UEs indicating that each of the plurality of UEs acknowledges that the first UE will initiate the coupled ranging session, before sending the initial message for initiating the coupled ranging session to the plurality of UEs.

5. The step of performing the combined distance measurement session with the plurality of UEs is: The method according to claim 1, comprising the step of receiving an initial message from the second UE for initiating the coupled ranging session with the plurality of UEs, including the plurality of UEs and the second UE.

6. The method according to claim 1, wherein the message to the plurality of UEs for combining the separate distance measurement sessions, indicating that the first UE will initiate the combined distance measurement session, further indicates that the first UE will become a positioning anchor, and the combined distance measurement session with the plurality of UEs includes a combined positioning session that uses the first UE as the positioning anchor.

7. The process further includes determining the signal intensity characteristics of the distance measurement signals in the separate distance measurement sessions initiated by the plurality of UEs, The method according to claim 1, wherein the message to the plurality of UEs for combining the separate distance measurement sessions further indicates the signal intensity characteristics of the distance measurement signals in the separate distance measurement sessions.

8. The combined distance measurement session includes all UEs participating in the separate distance measurement session, including the first UE, the plurality of UEs, and the plurality of response UEs. The aforementioned method, The steps include determining that the distance measurement signal broadcast in multiple combined distance measurement sessions is not received by another UE more than a predetermined threshold number of times, The steps include sending a second message to the multiple UEs to separate the combined ranging session, indicating that the multiple UEs will start separate ranging sessions, and The method according to claim 1, further comprising:

9. The method according to claim 1, further comprising the step of receiving possibility messages from the plurality of UEs indicating the availability of joining distance measurement sessions, wherein the messages sent to the plurality of UEs to join the separate distance measurement sessions are at least partially in response to the possibility messages indicating the availability of joining distance measurement sessions.

10. The method according to claim 1, wherein each of the first UE and the plurality of UEs is a vehicle-based UE, a pedestrian-based UE, or a roadside unit.

11. A first UE configured for distance measurement between user devices (UEs), A wireless transceiver configured to communicate wirelessly with entities in a wireless network, At least one memory, The wireless transceiver and at least one processor coupled to the at least one memory The at least one processor is provided The wireless transceiver receives initial messages from multiple UEs to initiate separate distance measurement sessions, Sending a message to the multiple UEs via the wireless transceiver indicating that the first UE will initiate a combined ranging session, for combining the separate ranging sessions, After sending the above, the coupled distance measurement session with the multiple UEs is performed. A first UE is configured to perform the following actions.

12. The first UE according to claim 11, further configured to perform the method described in any one of claims 2 to 10.

13. A method for measuring the distance between UEs performed by a first user device (UE), The steps include sending an initial message to the second UE to start the first ranging session, The steps include receiving a message from the second UE indicating that the second UE will initiate a combined ranging session, for combining the first ranging session with a second ranging session initiated by the third UE, After the receiving step, the step of performing the coupled distance measurement session with the second UE, Methods that include...

14. The steps include receiving an initial message from the second UE to start the combined distance measurement session, The method further includes sending a response message to the second UE indicating that the second UE will initiate the combined ranging session, wherein the step of sending the initial message includes broadcasting the initial message for initiating the first ranging session to the second UE and the fourth UE, and the method The steps include receiving a second message from the fourth UE to combine the first distance measurement session with the second distance measurement session initiated by the third UE, indicating that the fourth UE will initiate the combined distance measurement session, The steps include sending the response message to the second UE indicating that the second UE will start the coupled ranging session, The steps include receiving an initial message from the second UE to start the combined distance measurement session, and It further includes, The method according to claim 13, wherein the combined ranging session includes the second UE, the third UE, and the fourth UE.

15. The method of claim 14, wherein the step of sending the response message to the second UE indicating that the message from the second UE will be a positioning anchor, the second message from the fourth UE will not be a positioning anchor, and the second UE will initiate the coupled ranging session, is in response to the second UE indicating that it will be a positioning anchor, and the coupled ranging session includes a coupled positioning session using the second UE as the positioning anchor.

16. The method of claim 14, wherein the message from the second UE further indicates a first value of the signal intensity characteristics of the distance measuring signals in the first and second distance measuring sessions as measured by the second UE, the second message from the fourth UE indicates a second value of the signal intensity characteristics of the distance measuring signals in the first and second distance measuring sessions as measured by the fourth UE, and the step of sending the response message to the second UE indicating that the second UE will start the combined distance measuring session is in response to the first value of the signal intensity characteristics being greater than the second value of the signal intensity characteristics.

17. A first UE configured for distance measurement between user devices (UEs), A wireless transceiver configured to communicate wirelessly with entities in a wireless network, At least one memory, The wireless transceiver and at least one processor coupled to the at least one memory The at least one processor is provided An initial message to initiate the first distance measurement session is sent to the second UE via the aforementioned wireless transceiver, The second UE receives a message via the wireless transceiver indicating that the second UE will initiate a combined ranging session, for combining the first ranging session with a second ranging session initiated by the third UE. After receiving the aforementioned information, the coupled distance measurement session with the second UE is performed. A first UE is configured to perform the following actions.

18. The first UE according to claim 17, further configured to perform the method described in any one of claims 14 to 16.

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