Optimization of ranging sessions initiated by vehicle and pedestrian UEs

Abstract

In separate ranging sessions, the responding user equipment (UE) can determine whether there is a collision between ranging signals assigned to be broadcast in these separate ranging sessions. A collision in the ranging signals is detected when the ranging signals have the same frequency and broadcast time (e.g., the broadcast time of one ranging signal is within a predetermined amount of time for another ranging signal). When a collision in the ranging signals is detected, the responding UE sends a message indicating the likelihood of a collision to the initiating UE. The available time for broadcasting the ranging signal can be determined, for example, by either the responding UE or the initiating UE. The initiating UE can initiate a new ranging session based on the available time for broadcasting the ranging signal, or it can continue the ranging session if there is a possibility that the responding UE will not participate.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to U.S. nonprovisional application No. 17 / 179,548, filed February 19, 2021, entitled “OPTIMIZATION OF RANGING SESSIONSINITIATED BY VEHICLE AND PEDESTRIAN UES”, which has been assigned to the assignee of this application and is expressly incorporated herein by reference in its entirety.

[0003] background Background Technology

[0004] The subject matter disclosed herein relates to wireless communication systems, and more particularly to methods and apparatus for ranging or locating user equipment in distributed wireless communication systems.

[0005] Relevant background

[0006] Obtaining accurate location information for user equipment (such as cellular phones or other wireless communication devices) is becoming increasingly common in the communications industry. For example, obtaining highly accurate locations of vehicles or pedestrians is crucial for autonomous vehicle driving and pedestrian safety applications.

[0007] A common method for determining device location is using a satellite positioning system (SPS), such as the well-known Global Positioning Satellite (GPS) or Global Navigation Satellite System (GNSS), which employs several satellites in orbit around the Earth. However, in some scenarios, location determination signals from SPS can be unreliable or unavailable, for example, during adverse weather conditions or in areas with poor satellite signal reception (such as tunnels or parking lots). Furthermore, positioning information generated using SPS is prone to inaccuracies. For example, off-the-shelf GPS positioning devices have an accuracy of only a few meters, which is not optimal for ensuring safe autonomous driving and navigation.

[0008] Coordination or autonomous driving requires communication between vehicles, which can be direct or indirect (e.g., via infrastructure components such as roadside units (RSUs)). For vehicle safety applications, both positioning and ranging are crucial. For example, vehicle user equipment (UEs) can use sidelink signaling to perform positioning and ranging, such as broadcasting ranging signals to other vehicle UEs or pedestrian UEs to determine the relative position of the transmitter. Accurate and timely knowledge of the relative position or range relative to nearby vehicles enables autonomous vehicles to safely maneuver and negotiate traffic conditions. For example, round-trip time (RTT) is a technique commonly used to determine the range between transmitters. RTT is a two-way messaging technique where the time (minus processing delay) between the first device sending a ranging signal and the second device receiving acknowledgment (e.g., in the form of a returned ranging signal) corresponds to the distance (range) between the two devices.

[0009] In a distributed system, ranging sessions (i.e., those without infrastructure support for coordinated message passing) can lead to multiple ranging sessions occurring simultaneously, potentially involving overlapping sets of participating UEs. For example, multiple initiating UEs may initiate separate ranging sessions to the same responding UE, which could result in conflicting messages or signaling within the ranging sessions. Consequently, in situations where multiple ranging sessions can occur simultaneously in a distributed system, a lack of control or optimization over the ranging sessions may inhibit the participation of responding UEs and potentially disrupt UE ranging and positioning.

[0010] Overview

[0011] The responding user equipment (UE) included in separate ranging sessions can determine whether there is a conflict between ranging signals assigned to be broadcast in these separate ranging sessions. For example, a conflict in the ranging signals may be detected when the ranging signals have the same frequency and broadcast time (e.g., the broadcast time of one ranging signal is within a predetermined amount of time for another ranging signal). When a conflict in the ranging signals is detected, the responding UE sends a message indicating the likelihood of a conflict to the initiating UE. The responding UE may additionally determine the available time for broadcasting the ranging signal and provide the available time to the initiating UE, or the initiating UE may determine the available time. The initiating UE may reconstruct and initiate a new ranging session based on the available time for broadcasting the ranging signal, or may continue the ranging session if there is a possibility that the responding UE will not participate.

[0012] In one implementation, a method for ranging between UEs, performed by a responding user equipment (UE), includes: receiving from a first initiating UE a first ranging pre-request message to initiate a first ranging session, the first ranging pre-request message including first ranging signal resources, the first ranging signal resources including a time and frequency for the responding UE to broadcast a first ranging signal in the first ranging session; receiving from a second initiating UE a second ranging pre-request message to initiate a second ranging session, the second ranging pre-request message including second ranging signal resources, the second ranging signal resources including a time and frequency for the responding UE to broadcast a second ranging signal in the second ranging session; determining a conflict between the first ranging signal and the second ranging signal based on the first ranging signal resources and the second ranging resources; sending to the first initiating UE a first ranging pre-request message acknowledging receipt of the first ranging pre-request message; and sending to the second initiating UE a second ranging pre-request message indicating a conflict with the second ranging signal resources used for the second ranging signal.

[0013] In one implementation, a responding UE configured to perform ranging between user equipments (UEs) includes: a radio transceiver configured to wirelessly communicate with entities in a wireless network; at least one memory; and at least one processor coupled to the radio transceiver and the at least one memory, wherein the at least one processor is configured to: receive from a first initiating UE a first ranging pre-request message to initiate a first ranging session, the first ranging pre-request message including first ranging signal resources, the first ranging signal resources including a first ranging signal for the responding UE to broadcast during the first ranging session. The system receives a second ranging pre-request message from the second initiating UE to initiate a second ranging session. The second ranging pre-request message includes second ranging signal resources, which include the time and frequency for the responding UE to broadcast the second ranging signal in the second ranging session. The system determines a conflict between the first ranging signal and the second ranging signal based on the first ranging signal resources and the second ranging resources. The system sends a first ranging pre-response message to the first initiating UE acknowledging receipt of the first ranging pre-request message. The system then sends a second ranging pre-response message to the second initiating UE indicating a conflict with the second ranging signal resources used for the second ranging signal.

[0014] In one implementation, a responding UE is configured to perform ranging between user equipments (UEs). The responding UE includes: means for receiving from a first initiating UE a first ranging pre-request message to initiate a first ranging session, the first ranging pre-request message including first ranging signal resources, the first ranging signal resources including a time and frequency for the responding UE to broadcast a first ranging signal in the first ranging session; means for receiving from a second initiating UE a second ranging pre-request message to initiate a second ranging session, the second ranging pre-request message including second ranging signal resources, the second ranging signal resources including a time and frequency for the responding UE to broadcast a second ranging signal in the second ranging session; means for determining a conflict between the first ranging signal and the second ranging signal based on the first ranging signal resources and the second ranging resources; means for sending to the first initiating UE a first ranging pre-request message acknowledging receipt of the first ranging pre-request message; and means for sending to the second initiating UE a second ranging pre-request message indicating a conflict with the second ranging signal resources used for the second ranging signal.

[0015] In one implementation, a non-transient storage medium includes program code stored thereon, the program code being operable to configure at least one processor in a responding user equipment for ranging among UEs, the program code including instructions for: receiving from a first initiating UE a first ranging pre-request message to initiate a first ranging session, the first ranging pre-request message including a first ranging signal resource, the first ranging signal resource including a time and frequency for the responding UE to broadcast a first ranging signal in the first ranging session; receiving from a second initiating UE a second ranging pre-request message to initiate a second ranging session, the second ranging pre-request message including a second ranging signal resource, the second ranging signal resource including a time and frequency for the responding UE to broadcast a second ranging signal in the second ranging session; determining a conflict between the first ranging signal and the second ranging signal based on the first ranging signal resource and the second ranging resource; sending to the first initiating UE a first ranging pre-request message acknowledging receipt of the first ranging pre-request message; and sending to the second initiating UE a second ranging pre-request message indicating a conflict with the second ranging signal resource used for the second ranging signal.

[0016] In one implementation, a method for ranging between UEs performed by an initiating user equipment (UE) includes: transmitting a first ranging pre-request message to a responding UE to initiate a first ranging session, the first ranging pre-request message including a first ranging signal resource, the first ranging signal resource including a time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session; and receiving a first ranging pre-response message from the responding UE, the first ranging pre-response message indicating a conflict between the first ranging signal resource for the first ranging signal and a second ranging signal resource for a second ranging signal for a second initiating UE.

[0017] In one implementation, an initiating UE configured to perform ranging between user equipments (UEs) includes: a radio transceiver configured to wirelessly communicate with entities in a wireless network; at least one memory; and at least one processor coupled to the radio transceiver and the at least one memory, wherein the at least one processor is configured to: transmit a first ranging pre-request message to a responding UE to initiate a first ranging session, the first ranging pre-request message including first ranging signal resources, the first ranging signal resources including time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session; and receive a first ranging pre-response message from the responding UE, the first ranging pre-response message indicating a conflict between the first ranging signal resources for the first ranging signal and a second ranging signal resources for a second ranging signal for a second initiating UE.

[0018] In one implementation, an initiating UE configured to perform ranging between user equipments (UEs) includes: means for transmitting a first ranging pre-request message to a responding UE to initiate a first ranging session, the first ranging pre-request message including first ranging signal resources, the first ranging signal resources including time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session; and means for receiving a first ranging pre-response message from the responding UE, the first ranging pre-response message indicating a conflict between the first ranging signal resources for the first ranging signal and second ranging signal resources for a second ranging signal for a second initiating UE.

[0019] In one implementation, a non-transient storage medium includes program code stored thereon, the program code being operable to configure at least one processor in an initiating user equipment (UE) for ranging between UEs, the program code including instructions for: transmitting to a responding UE a first ranging pre-request message to initiate a first ranging session, the first ranging pre-request message including a first ranging signal resource, the first ranging signal resource including a time and frequency for the responding UE to broadcast a first ranging signal in the first ranging session; and receiving from the responding UE a first ranging pre-response message, the first ranging pre-response message indicating a conflict between the first ranging signal resource for the first ranging signal and a second ranging signal resource for a second ranging signal for a second initiating UE. Brief description of the attached diagram

[0021] Non-limiting and non-exhaustive aspects are described with reference to the following figures, wherein, unless otherwise specified, similar reference numerals are used throughout the figures to refer to similar parts.

[0022] Figure 1 The explanation describes a wireless communication system with distributed communication, which includes ranging signaling for supporting multiple ranging sessions and / or positioning.

[0023] Figure 2 The signaling diagram illustrates the timing and frequency of various messages that can be sent and received by the initiating UE and three responding UEs for a ranging or positioning session.

[0024] Figure 3 The illustration shows two separate ranging sessions, where collisions will occur due to PRS signals broadcast by the responder.

[0025] Figure 4 This is a diagram explaining the conflicts in PRS broadcast times and how to determine available broadcast times.

[0026] Figure 5 The signaling flow for separate ranging sessions with conflicting PRS broadcast times is explained, where the ranging sessions are rescheduled.

[0027] Figure 6 The signaling flow for separate ranging sessions with conflicting PRS broadcast times is explained, where no rescheduling of the ranging session is required.

[0028] Figure 7 A schematic block diagram illustrating some exemplary features of the UE is shown.

[0029] Figure 8 This is a flowchart explaining the method for ranging between UEs implemented by the responding UE.

[0030] Figure 9 This is a flowchart explaining the method for ranging between UEs implemented by the initiating UE.

[0031] Detailed description

[0032] Distributed approaches can be used for ranging and locating vehicles, roadside units (RSUs), and pedestrians, avoiding the need for centralized base station coordination and relay communication. This communication can be used in applications such as autonomous driving and vehicle safety. Communication used in distributed approaches can occur, for example, between vehicles or directly between vehicles and RSUs or pedestrians. These communications can include message and information elements (IEs), which vehicles can utilize to provide the information required for autonomous driving.

[0033] For example, for the safe operation of autonomous vehicles, it is necessary to determine their relative position or range to other vehicles. Various methods can be used to derive the relative positions between vehicles. For instance, ranging signaling can be used to derive the relative positions of vehicles. Ranging signals are sometimes referred to as physical ranging signals, positioning ranging signals, positioning reference signals, or physical reference signals, and are collectively referred to herein as PRS signals. PRS signals can be broadcast, for example, by the user equipment (UE) (sometimes referred to as V-UE) within the vehicle and received by other V-UEs and / or infrastructure (e.g., RSU) or pedestrian-held UEs using direct communication systems such as Dedicated Short Range Communication (DSRC), Cellular Vehicle-to-Everything (C-V2X) communication, and even 5G New Radio (NR) communication. PRS signals are used to determine the range to the broadcasting vehicle, for example, using one-way ranging, round-trip time (RTT) positioning operations, or other standard positioning operations such as Time of Arrival (TOA), Time Difference of Arrival (TDOA), or Observed Time Difference of Arrival (OTDOA) operations.

[0034] In a distributed system, individual UEs can use messages and location signals directly transmitted to other UEs to perform ranging relative to other nearby UEs. In an RTT-based ranging session, for example, each UE transmits and receives multiple messages and signals. For example, an initial set of pre-ranging signal messages (PRS messages) is transmitted and received to request and accept a ranging session, followed by broadcasting a ranging signal (PRS signal) for measurement, and then exchanging a set of post-ranging signal messages (PRS messages) with measurement payloads. For RTT-based ranging and positioning, for example, the time of arrival (TOA) and departure time (TOD) measurements of the transmitted and received PRS signals can be provided in the PRS messages and used by each UE pair to determine the range between these UEs. PRS messages and PRS messages can be transmitted on licensed spectrum to ensure reliability, while PRS signals can be broadcast on unlicensed spectrum (e.g., to enjoy greater available bandwidth in, for example, the UNI-III spectrum).

[0035] The distributed mechanism ensures minimal overhead, but multiple nearby UEs can independently initiate separate ranging sessions. Thus, multiple uncoordinated ranging sessions can be initiated autonomously by separate UEs. For example, without overhead communication to control the ranging session, multiple UEs can separately broadcast their own pre-PRS signals to the same set of responding UEs, resulting in independent ranging sessions involving the same responding UEs and occurring simultaneously. For instance, multiple V-UEs can initiate separate ranging sessions using the same set of RSUs. Furthermore, UEs held by nearby pedestrians can also initiate ranging sessions using the same set of RSUs. Therefore, multiple separate ranging sessions can be initiated simultaneously to one or more of the same responding UEs. As an example, separate ranging sessions can be initiated by the initiating UE, for example, because they are outside each other's coverage area, and thus will not include other initiating UEs in the ranging session and / or will not receive pre-PRS messages from other initiating UEs. Separate ranging sessions can be initiated by separate initiating UEs for other reasons, such as limiting the responding UE to UEs that know its location (e.g., the anchor UE) and can be used to locate the initiating UE.

[0036] A responding UE included in multiple simultaneous ranging sessions may have conflicting messages or signals in separate ranging sessions. For example, a responding UE may receive pre-PRS messages from multiple initiating UEs requesting the responding UE to broadcast a PRS signal on the same channel (e.g., CH 171) and at approximately the same time, resulting in PRS signal conflict. If the times used to broadcast the PRS signal in each ranging session are close, the responding UE may not be able to use the same channel to broadcast the PRS to two initiating UEs.

[0037] Accordingly, in one implementation, as discussed herein, a responding UE receiving multiple pre-ranging request messages, including the time and frequency for broadcasting the ranging signal, can determine whether a conflict exists between the various ranging sessions in separate ranging sessions. A conflict may be detected if the times for broadcasting the ranging signal are within a predetermined amount of time from each other and the same frequency will be used to broadcast the ranging signal. The responding UE may send an indication of a conflict in the ranging signal to at least one of the initiating UEs. For example, the responding UE may send an acknowledgment to a first initiating UE and may send the conflict indication to the other initiating UEs. In some implementations, the responding UE may determine the available time for broadcasting additional ranging signals and may provide that available time along with the conflict indication. In some implementations, an initiating UE that receives the conflict indication may continue the ranging session, and the responding UE may broadcast the ranging signal (if possible, i.e., if no conflict occurs). In another implementation, an initiating UE that receives the conflict indication may send another pre-ranging request with a different time for the responding UE to broadcast the ranging signal. Accordingly, multiple ranging sessions can continue with reduced likelihood of conflict in signal transmissions by overlapping responding UEs, thereby increasing the likelihood of successful ranging and positioning of the UE.

[0038] Figure 1 The wireless communication system 100 describes distributed communication, including ranging signaling as described herein to support multiple ranging sessions and / or positioning. The wireless communication system 100 describes a first vehicle 102 (e.g., V-UE 102) having a first wireless device, which is wirelessly communicating with another V-UE 104 (described as a second vehicle). V-UE 102 and V-UE 104 may include, but are not limited to, on-board units (OBUs), vehicles or their subsystems, or various other communication devices. V-UE 102 and 104 operate and provide communication on behalf of their associated vehicles, and therefore may sometimes 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, for example, be two vehicles traveling on a road together with other vehicles not described.

[0039] The wireless communication system 100 may use, for example, vehicle-to-everything (V2X) communication standards, in which information is transferred between vehicles and other entities within the wireless communication network. V2X services include, for example, services for vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P), vehicle-to-infrastructure (V2I), and vehicle-to-network (V2N). V2X standards are designed to develop autonomous or semi-autonomous driving systems (such as Advanced Driver Assistance Systems (ADAS)) that assist drivers in making critical decisions (such as lane changes, speed changes, and overtaking speeds) and can be used to assist parking, as described herein. Low latency communication is used in V2X and is therefore suitable for precise relative positioning, for example, using ranging signals (such as one-way ranging, RTT, TDOA, etc.).

[0040] Generally, there are two operating modes for V2X services, as defined in 3GPP TS23.285. One operating mode uses direct wireless communication between V2X entities, sometimes referred to as sidelink communication. The other operating mode uses network-based wireless communication between entities. These two operating modes can be combined, or other operating modes can be used if needed.

[0041] The wireless communication system 100 can operate using direct or indirect wireless communication between UE 102 and UE 104. For example, wireless communication can be via a proximity-based service (ProSe) direct communication (PC5) reference point as defined in 3GPP TS23.303, and can be via wireless communication according to IEEE 1609, WAVE (Wave-Aspect Radio Access), Intelligent Transportation Systems (ITS), and IEEE 802.11p, on the 5.9 GHz ITS band, or other direct wireless connections between entities. Thus, as explained, 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 unit (RSU) 110 via vehicle-to-infrastructure (V2I) communication links 107 and 109, respectively. RSU 110 may include a backhaul connection to the network as explained by wired connection 111, but may also be connected to a base station via a wireless Uu interface. RSU 110 may be, for example, a fixed infrastructure entity that supports V2X applications and can exchange messages with other entities that support V2X applications. An RSU may be a logical entity that combines V2X application logic with the functionality of a base station in the RAN, such as an eNB, ng-eNB, or eLTE (referred to as an eNB-type RSU), or a gNB, or a UE (referred to as a UE-type RSU). RSU 110 may be used in conjunction with UE 102, 104, or other UEs for ranging, and because the location of RSU 110 can be precisely known, RSU 110 can be used as an anchor UE to determine the location of UE 102, 104, or other UEs. RSU 110 may sometimes be referred to herein as UE 110. UE 102, 104, and UE 110 may communicate with additional entities (such as additional vehicles, RSUs) or with UE 112 held by pedestrian 114 using a direct communication link. For example, UE 102 can communicate with UE 112 via V2V communication link 113, UE 104 can communicate with UE 112 via V2V communication link 115, and UE 110 can communicate with UE 112 via V2I communication link 117.

[0042] During direct communication with one or more entities in the V2X wireless communication system 100, each entity may provide V2X information in messages, such as the identifier of the V2X entity and other information, such as Common Awareness Messages (CAM) and Decentralized Notification Messages (DENM) or Basic Security Messages (BSM), which may be used for, for example, ADAS or security use cases.

[0043] In other implementations, UE 102 and UE 104 may communicate indirectly with each other, for example, via V2I communication links 107 and 109 through RSU 110, or via other network infrastructure (not shown), for example, using cellular vehicle-to-everything (CV2X). For example, vehicles may communicate via base stations in a radio access network (RAN), such as evolved B-nodes (eNBs) in LTE radio access and / or evolved LTE (eLTE) radio access, or next-generation evolved B-nodes (ng-eNBs) and / or NR B-nodes (gNBs) in fifth-generation (5G) radio access.

[0044] UEs 102 and 104 can initiate and perform ranging / location sessions, including sending pre-PRS messages, broadcasting PRS, and sending post-PRS messages on links 103, 107, 109, 113, or 115. These messages can be used to determine the range or relative location between UEs 102 and 104. The PRS broadcast by UEs 102 and 104 can be any signal suitable for ranging, as defined for DSRC or C-V2X. PRS can be broadcast on licensed or unlicensed spectrum. For example, in some implementations, PRS can be broadcast on 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 on unlicensed spectrum, a Listen-Before-Broadcast (LBT) protocol can be used.

[0045] When UEs 102 and 104 broadcast a PRS on V2V link 103, the range or relative position between UEs 102 and 104 can be directly determined. When UEs 102 and 104 broadcast a PRS on V2I links 107 and 109 or via links 113 and 115, the range or relative position between UE 102 and UE 110 or UE 112, and between UE 104 and UE 110 or UE 112, can be directly determined.

[0046] Direct wireless communication between UEs 102 and 104 and UEs 110 and 112 requires no network infrastructure and enables low latency communication, which is beneficial for accurate ranging or positioning. Accordingly, such direct wireless communication may be desirable for ranging over short distances (e.g., with nearby vehicles or infrastructure).

[0047] Figure 1 The UE shown (e.g., any one of V-UE 102, V-UE 104, RSU 110, and UE 112) can be configured to perform ranging and / or positioning operations, such as RTT-based ranging.

[0048] As an example, Figure 2 Signaling diagram 200 illustrates the timing and frequency of various messages used in a ranging or positioning session that can be sent and received by the initiating UE (UEX) and three responding UEs (UEA, UEB, and UEC). For example, Figure 2 The description covers capability message 201 and RTT-based ranging session 202, during which several messages are transmitted between the initiating UE and the responding UE, including a PRS pre-session message 204 requesting and accepting the ranging session, a PRS signal 208 for measurement, and a PRS post-session message 208 for exchanging measurement payloads. Each set containing PRS pre-session 204, PRS 206, and PRS post-session 208 can be considered a single unit or PRS cycle. Each PRS cycle includes PRS pre-session message 204, PRS signal 206, and PRS post-session message 208, and is therefore referred to herein as ranging session 202. The ranging session (PRS cycle) can be periodic with a period T_r, and the capability message can be periodic with a period T_c, where T_r > T_c. Figure 2 In the diagram, signaling from the initiating UEX is explained using a white box marked "X", signaling from the first responding UEA is explained using a gray box marked "A", signaling from the second responding UEA is explained using a shaded box marked "B", and signaling from the third responding UEA is explained using a black box marked "C". The signaling from the initiating UEX is the first box in each of the PRS pre-message 204, PRS signal 206, and PRS post-message 208, followed by the responding UEs (UEA, UEA, and UEA).

[0049] As explained, this includes a UE broadcast capability message 201 for both the initiating UE and the responding UE. The capability message is not part of the ranging session, but may include information that the initiating UE can use to initiate a ranging session with a selected UE. For example, the capability message may be on the ITS spectrum and may include the UE ID, the UE's ranging capabilities, the channels the UE is configured to use, MIMO (Multiple-Input Multiple-Output) capabilities, etc. The capability message may additionally indicate whether the UE needs to determine its location, or whether its location is known and can be used as an anchor UE for locating other UEs. It should be understood that, although... Figure 2 Capability message 201 is interpreted as having the same order as messages in ranging session 202, but the order may actually be different.

[0050] The PrePRS Message 204 (e.g., a Ranging Pre-Message) is used by the UE to request and acknowledge a ranging session. As explained, the PrePRS Message 204 may be transmitted on licensed spectrum to ensure reliability. The PrePRS Message 204 may be broadcast or unicast, for example, using a Radio Resource Control (RRC) connection. The initiating UE X broadcasts an Initial PrePRS Message 204 (PrePRS Request) to initiate a ranging session between the initiating UE and the responding UE and to provide information for that ranging session (explained with a white box marked with an X). For example, the PrePRS Message 204 from the initiating UE may include IDs for the participating UEs, namely the initiating ID and the responding ID. The PrePRS Request message may include a ranging session ID, the channel for the PRS broadcast by the initiating UE X and the responding UE, the PRS broadcast time, the maximum Listen Before Transmit (LBT) time, etc. For example, the PRS pre-request message from the initiating UE may include a PRS ID to be used by the initiating UE, and in some implementations, a PRS ID to be used by the responding UE. If the PRS ID will be fixed over multiple PRS exchanges (e.g., for multiple units in ranging session 202), the initiating UE may include an ID associated with the current PRS exchange, such as a session ID. The initiating UE may determine when the PRS signal 206 will be transmitted, for example, it may be configured from an upper layer in the initiating UE. The initiating UE may indicate the timing of the PRS by sending a timeslot number close to the desired PRS transmission time. In some implementations, the timeslot may be subject to local clock errors. The initiating UE may further provide the timing of the PRS to be transmitted 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 to be used by the initiating UE and the responding UE to broadcast the PRS signal 206. For example, the PRS frequency can be selected from the available set of total bandwidth, or it can be selected by sensing interference and selecting one or more channels whose average interference reference received power (RSRP) is less than a threshold. The initiating UE can indicate the number of PRS cycles it will perform during ranging session 202. The number of PRS cycles can be configured from the upper layer. For example, the PRS pre-cycle message for each PRS cycle can indicate the current PRS cycle relative to the requested total number of PRS cycles, wherein the number of the current cycle is incremented after each cycle is completed.

[0051] The initial PRS pre-request message from the initiating UE is received and decoded by the responding UE identified in the initial PRS pre-request message. The responding UE may send a pre-PRS message 204 as a response (described by a gray box marked A, a shaded box marked B, and a black box marked C, respectively). The pre-PRS message 204 may acknowledge the pre-PRS request message, which may additionally provide information for the ranging session. Each responding UE may indicate the PRS ID it will use, or may indicate that it will use the PRS ID indicated in the initial PRS pre-request message. If the PRS ID will be fixed over multiple PRS exchanges (e.g., multiple PRS cycles in ranging session 202), the responding UE may include an ID associated with the current PRS exchange, such as a session ID, which is received in the initial PRS pre-request message from the initiating UE. The responding UE may broadcast the PRS pre-request message 204, which may be received by the initiating UE (and other responding UEs). In some implementations, each responding UE can use unicast with an RRC connection to transmit the PRS pre-message 204 to the initiating UE.

[0052] PRS signal 206 is exchanged by the participating UEs. The initiating and responding UEs are aware of the expected timing and frequency of the PRS signal, and are aware of the PRS ID (and any session IDs used with the exchanged signal) used to broadcast PRS signal 206. PRS signal 206 can be, for example, a pseudo-noise (PN) sequence modulated by Quadrature Phase Shift Keying (QPSK) and may include a ranging session ID. PRS signal 206 can be broadcast on unlicensed spectrum subject to LBT constraints. In some implementations, when using unlicensed spectrum, the initiating UE X may reserve transmissions for responding UEs UEA, UEB, and UEC, so that these responding UEs do not need to perform LBT. For example, the initiating UE X broadcasts its PRS signal 206 at a predetermined time indicated in the pre-PRS message 204 (white box marked X). In some implementations, when the PRS signal is deployed in unlicensed spectrum, due to LBT constraints, the initiating UE broadcasts its PRS signal at a predetermined time plus a random waiting time. In some implementations, the LBT can be a Category 2 LBT with a fixed-window open channel assessment (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 PRS pre-message 204. The initiating UE stores the time instance when the PRS signal was broadcast, and the responding UE stores the time instance when the PRS signal was received. In some implementations, these time instances may be subject to local clock errors.

[0053] Similar to the initiating UE, each responding UE broadcasts its PRS signal 206 at the time and frequency assigned by the initiating UE in the initial PRS pre-message 204 (described by a gray box labeled A, a shaded box labeled B, and a black box labeled C, respectively). In some implementations, when the PRS signal is deployed in unlicensed spectrum, each responding UE may broadcast its PRS signal at a determined time plus a random waiting time due to LBT constraints. In some implementations, the LBT may be a Class 2 LBT with a fixed window CCA or a Class 4 LBT with a variable window CCA. Each responding UE uses a PRS signal corresponding to the PRS ID indicated in its PRS pre-message 204. Each responding UE stores an instance of when its PRS signal is broadcast, and the initiating UE (and optionally other responding UEs) stores an instance of when the PRS signal from each responding UE is received. In some implementations, these time instances may be subject to local clock errors.

[0054] Therefore, each UE records the time of departure (ToD) of its broadcast PRS signal and measures the time of arrival (ToA) of PRS signals received from other UEs. The PRS signal can be any signal suitable for ranging, such as those defined for DSRC or C-V2X (e.g., a PN sequence modulated with QPSK). The ToA and ToD resolutions of the PRS signal increase with increasing frequency bandwidth. In some implementations, the angle of departure (AoD) and angle of arrival (AoA) of the broadcast and received PRS signals can also be measured. Broadcasting on unlicensed spectrum is advantageous because a wider bandwidth is available. For example, in some implementations, the PRS can be broadcast on one or more UNII radio bands, including, for example, one or more of the UNII-1, UNII-2A, UNII-2B, or UNII-3 radio bands.

[0055] Post-PRS message 208 is sent by each UE to exchange measurement payloads. As explained, post-PRS message 208 may be transmitted on licensed spectrum to ensure reliability. In some implementations, post-PRS message 208 may be broadcast or unicast over an RRC connection. The initiating UE X sends its post-PRS message 208 (explained as a white box marked X) and indicates when it broadcasts the PRS signal 206 (ToD) and when it receives the PRS signal from the responding UE (ToA). In some implementations, ToA may be calculated as a relative time to ToD of its broadcast PRS signal, and this relative time may be provided. In some implementations, the relative time may approximate the closest multiple of the time scale shared by the initiating and responding UEs. In some implementations, the initiating UE may provide an indication of its location in post-PRS message 208 if known. For example, the location of the initiating UE 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 PRS post-message 208 may further include the AoD of its PRS signal 206 and the AoA of the PRS signal 206 received from the responding UE, the orientation of the initiating UE, the broadcast indicator of the PRS signal 206, the reception indicator of the PRS from the responding UE, and other relevant measurements, such as map information, the position of the reflector relative to the UE, etc.

[0056] Similar to the initiating UE, each responding UE transmits its post-PRS signal 208 (described by a gray box labeled A, a shaded box labeled B, and a black box labeled C, respectively) to provide a measurement payload. Each responding UE may indicate whether it received a PRS signal from the initiating UE, and may indicate when it broadcast a PRS signal 206 (ToD) and when it received a PRS signal (ToA) from the initiating UE (and optionally from other responding UEs). In some implementations, ToD may be calculated as a relative time with respect to ToA of the PRS signal from the initiating UE (and optionally with respect to ToA of the PRS from other responding UEs). In some implementations, the relative time may approximate the closest multiple of the time scale shared by the initiating UE and the responding UEs. In some implementations, the responding UE may provide an indication of its location in the post-PRS message 208, if known. For example, the location of the responding UE provided may be a location at a specific time, such as the arrival time of the PRS signal from the initiating UE or the departure time of its broadcast PRS signal. The PRS post-message 208 may further include the AoD of its PRS signal 206 and the AoA of the PRS signal 206 received from the initiating UE (and optionally from other responding UEs), the orientation of the initiating UE, the broadcast indicator of the PRS signal 206, the reception indicator of the PRS from the responding UE, and other relevant measurements, such as map information, the position of the reflector relative to the UE, etc.

[0057] After receiving the PRS message, the initiating UE can calculate its range (and in some implementations its location) (e.g., using a Kalman filter), and then transmit the next cycle of the PRS message at a time indicated by the upper layer or at a time determined autonomously by the initiating UE.

[0058] The time between the first PRS pre-message 204 and the last PRS post-message 208 can be the duration of the ranging session, and can be, for example, 100 milliseconds. The duration of each broadcast PRS signal 206 can be, for example, 47 microseconds. In some implementations, multiple PRS cycles (e.g., multiple instances of PRS pre-message 204, PRS 206, and PRS post-message 208) can be used together to provide higher accuracy.

[0059] Both the initiating UE and the responding UE can determine the range between themselves and each other UE in a ranging session based on the ToD and ToA of the broadcast PRS signal. For example, the RTT between any pair of UEs (which can be any pair of initiating and responding UEs) can be based on the PRS. i ToD of the signal i and ToA iTo determine (where i = 1 for PRS broadcast from the first UE and i = 2 for PRS broadcast from the second UE), such as the difference between ToD1 and ToA2 minus the difference between ToA1 and ToD2, for example as follows.

[0060] RTT = (ToD1 - ToA2) - (ToA1 - ToD2 Equation 1

[0061] The RTT value is the round-trip time of the signal, and the distance between UE1 and UE2 can be determined as RTT / 2c, where c is the speed of light.

[0062] If the locations of one or more responding UEs are known, the location of another UE can be determined using the range between the initiating UE and the responding UE, as well as the known location of one of the responding UEs, and thus the ranging session can be a location session. A responding UE with a known location that can be used for location determination may sometimes be referred to herein as an anchor UE. The location of the anchor UE can be provided to other UEs, for example, through message transmission in a PRS pre-message or PRS post-message. If the ranges to multiple anchor UEs are determined, the locations of these multiple anchor UEs can be used for multilateral location determination to determine the location of the initiating UE (or other responding UEs).

[0063] Angular measurements (e.g., AoD and AoA) can be used, for example, to assist in positioning. As an example, the relative positioning of two UEs can be determined based on the range between them and the measured AoA. With the relative positioning of the UEs determined, the actual positioning of the other UE can be determined if the actual positioning of one of the UEs is known (this can be provided, for example, in PRS pre-message 204 or PRS post-message 208). If a third UE knows the positioning of the two UEs, the range between the third UE and each of the other two UEs will produce two possible positioning for the third UE, which can be resolved based on the AoD / AoA information. For example, AoD may be useful if the AoA resolution is poor or incorrect. AoD can be measured, for example, based on the known orientation of the UE (e.g., determined by a magnetometer) and the direction of the transmitted signal relative to the UE (e.g., relative to the antenna array of the UE used for beamforming). AoA can be measured based on the phase difference between the received signal at different antenna elements of the antenna array and (e.g., determined by a magnetometer) the known orientation of the UE. Additionally, geographic constraints can be used to assist in positioning, for example, by constraining the possible location of a vehicle based on its reachability (such as roads).

[0064] As discussed above, due to the distributed mechanism used for ranging, multiple UEs may initiate independent ranging sessions that include at least some of the same responding UEs at approximately the same time. For example, two initiating UEs may separately broadcast their own pre-PRS signals to the same set of responding UEs, resulting in two independent ranging sessions that include the same responding UEs and occur at the same time. To illustrate, initiating UE X may send a pre-ranging request message with ranging session ID 182 and PRS channel 171 to responding UE A, and a second initiating UE Y may send a separate pre-ranging request message with ranging session ID 183 and PRS channel 171 to the same responding UE A. Responding UE A is thus included in both ranging session IDs 182 and 183, but if the PRS broadcast times are close, responding UE A may not be able to use channel 171 to broadcast PRS in the two ranging sessions for initiating UE X and initiating UE Y.

[0065] As an example, Figure 3 The illustration shows two separate ranging sessions 302 and 312, where the PRS signals 306 and 316 of the responding UEA may conflict. The first ranging session 302, including the pre-PRS message 304, PRS signaling 306, and post-PRS message 308, is between the first initiating UEX and the responding UEA. Signaling from the initiating UEX is illustrated with a white box marked "X," and signaling from the responding UEA is illustrated with a gray box marked "A." It should be understood that ranging sessions 302 and 312 may include multiple responding UEAs, but only the responding UEA is illustrated. The second ranging session 312, including the second pre-PRS message 314, the second PRS signaling 316, and the second post-PRS message 318, is between the second initiating UEA and the same responding UEA. In ranging session 312, signaling from the initiator UEY is explained using a dark gray box marked "Y", and signaling from the responder UEA is explained using a light gray box marked "A".

[0066] The first initiator, UEX, may send a PRS pre-send message 304 to the responding UEA. As described above, the PRS pre-send message 304 may include a ranging session ID, the channel for the responding UEA to broadcast the PRS, the time for the responding UEA to broadcast the PRS, and the maximum LBT or other delay time allowed for broadcasting the PRS, etc. The second initiator, UEY, may send a second PRS pre-send message 314 to the responding UEA immediately after the first initiator, UEX, sends the PRS pre-send message 304. Similar to the first PRS pre-send message 304, the second PRS pre-send message 314 may include a ranging session ID, the channel for the responding UEA to broadcast the PRS, the time for the responding UEA to broadcast the PRS, and the maximum LBT or other delay time allowed for broadcasting the PRS, etc. The second PRS pre-message 314 may include the same channel and timing for broadcasting the PRS by the responding UEA as provided in the first PRS pre-message 304, as indicated by line 320 between the PRS signal 306 from the responding UEA in the first ranging session 302 (marked with a light gray box labeled A) and the PRS signal 316 from the responding UEA in the second ranging session 312 (marked with a light gray box labeled A).

[0067] Therefore, as in Figure 3 As can be seen, the broadcast time of the first PRS signal 306 broadcast by the responding UEA in the first ranging session 302 and the broadcast time of the second PRS signal 316 broadcast in the second ranging session 312 may be the same or nearly the same, as explained by line 320. The responding UEA cannot broadcast different PRS signals to ranging sessions 302 and 312 simultaneously, for example, because the ranging session IDs of the two ranging sessions are different, resulting in different PRS sequence IDs. Accordingly, if the first PRS 306 and the second PRS 316 are assigned the same channel and the same broadcast time, the responding UEA will be unable to broadcast the PRS signal at the time assigned to the two ranging sessions.

[0068] Accordingly, in one implementation, if the responding UEA determines a PRS conflict assigned in multiple ranging sessions, the responding UEA may send a message indicating the existence of a conflict to the second initiating UEA (e.g., a PRS pre-response message 314 explained with a gray box marked A). In some implementations, the responding UEA may further provide an indication of the available time for PRS broadcasting. The first initiating UEA may continue the first ranging session 302, and the second initiating UEA may continue the second ranging session 312, which is possible without the responding UEA, or may reconstruct the second ranging session using the new broadcast time available for the responding UEA for the second PRS and send a new PRS pre-request message with the new PRS broadcast time available for the responding UEA to the responding UEA.

[0069] Figure 4 This is a diagram 400 illustrating the conflict between the responder UEA and the PRS broadcast time, as well as the determination of the available broadcast time. Figure 4 The timeline explains the first PRS broadcast time (Btime) (as indicated by arrow 402) and the associated reserved LBT time 404 (or other predetermined delay time) and the second PRS broadcast time (Btime) (as indicated by arrow 406). In some instances, for example, the first PRS broadcast time 402 and the reserved LBT time 404 may be assigned by the first initiator UEX for the first PRS 306 (e.g., in...). Figure 3 The PRS pre-request message 304, as illustrated by the white box marked with an X, is used to explain the second PRS broadcast time 406, and the second PRS broadcast time 406 can be assigned by the second initiator UEY for the second PRS 316 (e.g., in...). Figure 3 The assignment is shown in the PRS pre-request message 314, illustrated by a dark gray box marked Y. However, in some instances, the second initiator UEY may assign a broadcast time to the second PRS 316 prior to the broadcast time assigned to the first PRS 306, in which case... Figure 4 The first PRS broadcast time 402 and the LBT retention time 404 explained herein can correspond to Figure 3 The second PRS 316 shown and the second PRS broadcast time 406 can correspond to Figure 3 The first PRS 306 is shown. Nevertheless, for ease of reference, as discussed herein (unless otherwise indicated), Figure 4 The first PRS broadcast time 402 and the reserved LBT time 404 correspond to Figure 3 The first PRS 306 in, and Figure 4 The second PRS broadcast time 406 corresponds to Figure 3 The second PRS 316 in the document.

[0070] If the frequencies assigned to PRS broadcasts for multiple ranging sessions are the same, the responding UEA can determine a PRS conflict for these ranging sessions if the second PRS broadcast time 406 is within a predetermined amount of time from the first PRS broadcast time 402. For example, Figure 4 Box 408 illustrates the predetermined time amount used to determine a conflict (sometimes referred to herein as the conflict threshold). For example, the conflict threshold 408 could be the full duration of the LBT retention time 404 (or other predetermined delay time). Because the LBT retention time is the maximum LBT time, it will be highly likely that the first PRS will be broadcast before the end of the LBT retention time 404, and accordingly, the predetermined conflict threshold 408 may be less than the LBT retention time 404 if desired.

[0071] like Figure 4 As explained, the second PRS broadcast time 406 falls within the conflict threshold 408 from the first PRS broadcast time 402, and thus the first PRS and the second PRS are determined to be in conflict. Therefore, the responder UEA sends a message to the second initiator UEY indicating that its assigned PRS is in conflict with another PRS. For example, see reference... Figure 3 The responding party UEA may send a response PRS pre-message 314 (described by a light gray box marked A) with a negative acknowledgment (NACK) message to the second initiating party UEY to indicate that the assigned PRS is in conflict with the PRS in another ranging session, but may send a response PRS pre-message 304 to the first initiating party UEX to acknowledge the ranging session.

[0072] Furthermore, the responder UEA can further determine the time available for broadcasting the second PRS and can provide the second initiator UEY with an indication of the available time available for the second PRS. For example, such as Figure 4 As explained in the diagram, the responder UEA has time available for the second PRS before the first broadcast time 402 (explained in box 410) and time available for the second PRS after the LBT retention time 404 (explained in box 412). In some implementations, the time between the conflict threshold 408 and the end of the LBT retention time 404 (if any) (e.g., indicated in box 414) may be considered by the responder UEA as available time for the second PRS, although the LBT for the first PRS may potentially extend beyond the conflict threshold 408. The responder UEA may provide the second initiator UEA with the available time for broadcasting the second PRS. For example, the responder UEA may define the available time based on the initial time and its duration in boxes 410 and 412, the start time and end time in boxes 410 and 412, or may provide the first broadcast time 402 and optionally the LBT retention time 404 (or the predetermined conflict threshold 408), according to which the initiator UEA can determine the available time for broadcasting the PRS.

[0073] In some implementations, the responder UEA may not provide available time to the initiator UEY, and the initiator UEY may determine the available time for the responder UEA to broadcast the PRS based on the second PRS broadcast time 406.

[0074] Upon receiving an indication of a PRS conflict from the responding UEA, the initiating UEY can take various actions. For example, in one implementation, the initiating UEY can simply continue the second ranging session with the responding UEA and other responding UEs. If the responding UEA is able, it will broadcast the second PRS at the assigned second PRS broadcast time 406 (e.g., there is actually no conflict with the first PRS broadcast time 402, since the first PRS was broadcast before the second PRS broadcast time 406). Alternatively, if the first PRS cannot be broadcast until after the second PRS broadcast time 406, but is broadcast before the reserved LBT time of the second PRS broadcast time, the responding UEA can still broadcast the second PRS. For example, if there are many responding UEs and the initiating UEY does not need the presence of a PRS signal from the responding UEA, it may be advantageous for the initiating UEY to continue the second ranging session, even if the responding UEA may not broadcast its PRS.

[0075] In another implementation, if the initiating UEY receives available broadcast time from the responding UEA, the initiating UEY may reconstruct the second ranging session to avoid PRS conflicts, for example, by using a different second PRS broadcast time for the responding UEA that falls within the available broadcast time. For instance, the initiating UEY may send a new PRS pre-request message for the new second ranging session to all responding UEs. The new PRS pre-request message may include the same parameters used in the original PRS pre-request message for the second ranging session, but may include a new ranging session ID and a different second PRS broadcast time for the responding UEA (e.g., the PRS broadcast time for other responding UEs may not change).

[0076] In another implementation, the responding UEA may not send available time for broadcasting, and the initiating UEY may determine the available time for the responding UEA to broadcast the PRS without assistance from the responding UEA. For example, once the initiating UEY receives an indication of a PRS conflict from the responding UA, the initiating UEY may estimate the available time for the responding UEA to broadcast the PRS based on the initial second PRS broadcast time 406 and the buffer time 414 around the second PRS broadcast time 406. For example, the buffer time 414 may be a predetermined amount of time before and after the second PRS broadcast time 406 that the initiating UEY will assume the responding UEA cannot broadcast the second PRS, and thus the initiating UEY may assume that the time outside the buffer time 414 is the available broadcast time for the responding UEA. For example, the duration of the buffer time 414 may be based on the reserved LBT time and / or conflict threshold after and before the second PRS broadcast time 406. For example, the second initiating UEY may not know the assigned second PRS 316 ( Figure 3 (As shown in the diagram) whether it is before or after other conflicting PRS, and accordingly, buffer times are used before and after the second PRS broadcast time 406.

[0077] Once the initiating UEY determines the available broadcast time for the responding UEA, the initiating UEY can reconstruct the second ranging session to avoid PRS conflicts, for example, by using a different second PRS broadcast time for the responding UEA that falls within the available broadcast time. For instance, the initiating UEY can send a new PRS pre-request message for the new second ranging session to all responding UEs. The new PRS pre-request message may include the same parameters used in the original PRS pre-request message for the second ranging session, but may include a new ranging session ID and a different second PRS broadcast time for the responding UEA (e.g., the PRS broadcast time for other responding UEs may remain unchanged).

[0078] Figure 5 An example of signaling flow 500 for a separate ranging session initiated by a first initiator UEX 502 and a second initiator UEY 504, including a responder UEA and conflicting PRS broadcast times, is described, wherein the second initiator UEY 504 reschedules the second ranging session as discussed herein. The initiator UEX 502, the initiator UEY 504, and the responder UEA 506 can be one or more of the following: vehicle-based UEs (V-UEs) 102 and 104, RSU 110, or UE 112, as... Figure 1 As described in [the document]. It should be understood that, Figure 5The signaling for multiple ranging procedures involving only one responding UE (e.g., UEA 506) has been explained, but there may be additional responding UEs, which would involve similar... Figure 5 The additional communications shown. As explained, Figure 5 Communication between UEs 502, 504, and 506 can be direct communication between entities and can be done without involving infrastructure equipment such as base stations to forward messages between entities.

[0079] In Phase 1A, the first initiating UE, UEX 502, sends a pre-Rating Message (PRS) to request a ranging session with the responding UE, UEA 506. This PRS message may be transmitted via licensed spectrum. The PRS message may indicate ranging signal attributes to be used by the responding UE, UEA 506 (as well as the initiating UE and any other responding UE) in the ranging session with the initiating UE, UEX 502, such as session ID and PRS resources, including frequency channels and timing instances, including the PRS broadcast time and reserved LBT time (or other delay time), and a PRS identifier (ID).

[0080] In Phase 1B, the second initiator UEY 504 sends a pre-PRS message to request a ranging session with the responder UEA 506. The pre-PRS message in Phase 1B follows the pre-PRS message in Phase 1A, and thus the ranging session initiated by the pre-PRS message in Phase 1A is sometimes referred to as the first ranging session, and the ranging session initiated by the pre-PRS message in Phase 1B is sometimes referred to as the second ranging session. Similar to Phase 1A, the pre-PRS message sent in Phase 1B may be transmitted via licensed spectrum and may indicate ranging signal attributes to be used by the responder UEA 506 (as well as the initiator UEY 504 and any other responder UE) in the second ranging session with the initiator UEY 504, such as session ID and PRS resources, including frequency channels and timing instances, including the PRS broadcast time and reserved LBT time (or other delay time), and the PRS identifier (ID).

[0081] In phase 2, responder UEA 506 determines whether there is a conflict between the first PRS and the second PRS assigned in the first PRS pre-message of phase 1A and the second PRS pre-message of phase 1B, respectively. For example, in... Figure 4As discussed herein, a conflict can be determined if the PRS signals of two ranging sessions are assigned to the same channel and if the second PRS broadcast time is within a predetermined amount of time (e.g., a conflict threshold) of the first PRS broadcast time. The duration of the conflict threshold can be predetermined and, in some implementations, can be based on an approximate duration of the reserved LBT time (or other delay time). For example, the conflict threshold can be a percentage of the reserved LBT time associated with the first PRS broadcast (e.g., 100%, 80%, 60%, etc.). Other considerations and factors can be used to determine the duration of the conflict threshold. In some implementations, the responder UEA 506 can further determine the available time for PRS broadcasting, such as... Figure 4 As explained in the text. For example, available time can be determined based on the time before the first PRS broadcast time and after the LBT retention time or the conflict threshold time.

[0082] In Phase 3, in response to the PRS pre-request in Phase 1A, the responding UEA 506 sends a PRS pre-request message (ranging pre-request message) acknowledging receipt of the request to the first initiating UEX 502, thereby instructing the responding UEA 506 to accept the ranging session request from the initiating UEX 502. The PRS pre-request message in Phase 4A can be transmitted on licensed spectrum.

[0083] In Phase 4, in response to the PRS pre-request in Phase 1B, responding UEA 506 sends a PRS pre-request message (ranging pre-request message) to the second initiator UEA 504. Since the second PRS assigned in the second PRS pre-request message in Phase 1B conflicts with the first PRS assigned in the first PRS pre-request message in Phase 1A, the response PRS pre-request message in Phase 4 includes an indication of the PRS conflict, for example, using a negative acknowledgment (NACK) message. In some implementations, responding UEA 506 may include an indication of the available PRS broadcast time in the PRS pre-request message in Phase 4. For example, the indication of the available PRS broadcast time may be the start and end times of the available time, the start time and duration of the available time, the first PRS broadcast time, and optionally, a reserved LBT time or a conflict threshold duration, etc. The PRS pre-request message in Phase 4 may be transmitted on licensed spectrum.

[0084] In phase 5, the initiating party UEY 504 may determine the available PRS broadcast time for the responding party UEA 506, for example, based on the available PRS broadcast time provided in the pre-PRS message of phase 4, or, if the responding party UEA 506 does not include the available PRS broadcast time provided in the pre-PRS message of phase 4, the initiating party UEY 504 may determine the available time independently. For example, as Figure 4As discussed herein, the initiating party UEY 504 may define the time during which a PRS conflict may occur for the responding party UEA 506 using the buffer time before and after the assigned second PRS broadcast time, and the time outside the buffer time may be determined as the available PRS broadcast time for the responding party UEA 506. The initiating party UEA 504 may reconstruct the second ranging session based on the available PRS broadcast time for the responding party UEA 506.

[0085] In phase 6, the second initiator UEY 504 sends another pre-PRS message to request a second ranging session with the responder UEA 506. The pre-PRS message in phase 6 may be similar to the pre-PRS message in phase 1B (including ranging signal attributes that will be used by the initiator UEY 504 and any other responder UE in the ranging session), but may include a new session ID and reconfigured PRS resources for the responder UEA 506. The reconfigured PRS resources include frequency channels and a new timing instance, which includes a new PRS broadcast time and a reserved LBT time (or other delay time), as well as a PRS identifier (ID).

[0086] In phase 7, in response to the pre-PRS request from phase 6, responding UEA 506 sends a pre-PRS message (pre-ranging message) acknowledging receipt of the request to second initiator UEX 502, thereby instructing responding UEA 506 to accept the request for a ranging session from second initiator UEY 504. The pre-PRS message from phase 4A can be transmitted on licensed spectrum.

[0087] In Phase 8A, the first initiator UEX 502 broadcasts a PRS signal using the PRS resource set identified in the PRS pre-PRS message of Phase 1A. The PRS signal may be broadcast on unlicensed spectrum to utilize wideband. The first initiator UEX 502 records the Time of Distance (ToD) of the PRS signal and, in some implementations, records the AoD of the PRS signal, while the responder UEA 506 records the Time of A (ToA) of the PRS signal and, in some implementations, measures and records the AoA of the PRS signal.

[0088] In phase 8B, in response to receiving a PRS signal in phase 8A, responding UEA 506 uses the PRS resources (including frequency channel, PRS broadcast time, and LBT retention time) assigned in the PRS pre-PRS message of phase 1A to broadcast the PRS signal. The PRS signal may be broadcast on unlicensed spectrum to utilize wideband. Responding UEA 506 records the Time of Distance (ToD) of the PRS signal and, in some implementations, records the AoD of the PRS signal, while the first initiator UEX 502 records the Time of AoA of the PRS signal and, in some implementations, measures and records the AoA of the PRS signal.

[0089] In Phase 9A, the second initiator, UEY 504, broadcasts a PRS signal using the PRS resource set identified in the PRS pre-PRS message of Phase 6. The PRS signal may be broadcast on unlicensed spectrum to utilize wideband. The second initiator, UEY 504, records the Time of Distance (ToD) of the PRS signal and, in some implementations, records the AoD of the PRS signal, while the responder, UEA 506, records the Time of A (ToA) of the PRS signal and, in some implementations, measures and records the AoA of the PRS signal.

[0090] In phase 9B, in response to receiving a PRS signal in phase 9A, respondent UEA 606 broadcasts the PRS signal using the PRS resources (including frequency channels, revised PRS broadcast time, and reserved LBT time) assigned in the PRS pre-PRS message of phase 6. Because the PRS signal in phase 9B is broadcast using the revised PRS broadcast time, there is no conflict with the PRS broadcast in phase 8B. The PRS signal in phase 9B can be broadcast on unlicensed spectrum to utilize wideband. Respondent UEA 506 records the ToD of the PRS signal and, in some implementations, records the AoD of the PRS signal, while the second initiator UEA 504 records the ToA of the PRS signal and, in some implementations, measures and records the AoA of the PRS signal.

[0091] In phase 10A, the first initiator UEX 502 sends a post-PRS message to the responder UEA 506. This post-PRS message indicates the Time of Docking (ToD) of the PRS signal broadcast in phase 8A, and in some implementations, indicates the Area of ​​Docking (AoD) of the PRS signal broadcast in phase 8A, and indicates the Time of ApoA of the PRS signal received in phase 8B, and in some implementations, indicates the Area of ​​ApoA of the PRS signal received in phase 8B. If the location of the first initiator UEX 502 is known, the post-PRS message may further include the current location of the first initiator UEX 502.

[0092] In phase 10B, responder UEA 506 sends a post-PRS message to first initiator UEX 502. This post-PRS message indicates the ToA of the PRS signal received in phase 8A, and in some implementations, indicates the AoA of the PRS signal received in phase 8A, and indicates the ToD of the PRS signal broadcast in phase 8B, and in some implementations, indicates the AoD of the PRS signal broadcast in phase 8B. If the location of responder UEA 506 is known, the post-PRS message may further include the current location of responder UEA 506.

[0093] In phase 11A, the second initiator UEY 504 sends a post-PRS message to the responder UEA 506. This post-PRS message indicates the ToD of the PRS signal broadcast in phase 9A, and in some implementations, indicates the AoD of the PRS signal broadcast in phase 9A, and indicates the ToA of the PRS signal received in phase 9B, and in some implementations, indicates the AoA of the PRS signal received in phase 9B. If the location of the second initiator UEY 504 is known, the post-PRS message may further include the current location of the second initiator UEY 504.

[0094] In phase 11B, responder UEA 506 sends a post-PRS message to second initiator UEA 504. This post-PRS message indicates the ToA of the PRS signal received in phase 9A, and in some implementations, indicates the AoA of the PRS signal received in phase 9A, and indicates the ToD of the PRS signal broadcast in phase 9B, and in some implementations, indicates the AoD of the PRS signal broadcast in phase 9B. If the location of responder UEA 506 is known, the post-PRS message may further include the current location of responder UEA 506.

[0095] In phase 12A, the first initiator UEX 502 may determine the range between UEX 502 and the responder UEA 506 based on the ToD and ToA of the PRS signal broadcast in phases 8A and 8B. For example, this range may be based on the PRS signal. i ToD of the signal i and ToA i (Where i = 1 for PRS broadcast by initiator UEX 502 and i = 2 for PRS broadcast by responder UEA 506) is determined as follows:

[0096]

[0097] If the location of the responder UE 506 is known, for example, in the PRS post-message in phase 10B along with additional information (such as the AoA or AoD of the PRS signal or other responder UEs) Figure 5 If the location and range (not shown) or geographic information (such as street location) are provided together, the location of the initiator UEX 502 can be determined using, for example, multilateral positioning and constraints based on the AoA or AoD of the PRS signal and geographic information.

[0098] In phase 12B, the second initiator UEY 504 may determine the range between UEY 504 and the responder UEA 506 based on the ToD and ToA of the PRS signals broadcast in phases 9A and 9B, in a manner similar to that described in phase 12A. The location of the initiator UEY 504 may also be determined in a manner similar to that described in phase 12A.

[0099] In phase 12C, responder UEA 506 may determine the range between UEA 506 and the first initiator UEX 502, and the range between UEA 506 and the second initiator UEE 504, in a manner similar to that described in phases 12A and 12B, based on the ToA and ToD of the PRS signals broadcast in phases 8A and 8B, and in phases 9A and 9B, respectively. The location of responder UEA 506 may also be determined in a manner similar to that described in phase 12A, for example, based on the location of the first initiator UEX 502 or the second initiator UEE 504 (if provided at phases 10A and 10B).

[0100] Figure 6 An example of signaling flow 600 for a separate ranging session initiated by the first initiator UEX 602 and the second initiator UEY 604, including the responding party UEA and conflicting PRS broadcast times, is explained as discussed herein. Signaling flow 600 is similar to... Figure 5 The signaling flow shown is 500, but the second initiator UEY 604 does not reschedule the second ranging session. The initiator UEX 602, initiator UEY 604, and responder UEA 606 can be one or more of the following: vehicle-based UEs (V-UEs) 102 and 104, RSU 110, or UE 112, as shown. Figure 1 As described in [the document]. It should be understood that, Figure 6 The signaling for multiple ranging procedures involving only one responding UE (e.g., UEA 606) has been explained, but there may be additional responding UEs, which would involve similar... Figure 6 The additional communications shown. As explained, Figure 6 Communication between UEs 602, 604, and 606 can be direct communication between entities and can be done without involving infrastructure equipment such as base stations to forward messages between entities.

[0101] In Phase 1A, the first initiating UE, UEX 602, sends a pre-Rating Message (PRS) to request a ranging session with the responding UE, UEA 606. This PRS message may be transmitted via licensed spectrum. The PRS message may indicate ranging signal attributes to be used by the responding UE, UEA 606 (as well as the initiating UE and any other responding UE) in the ranging session with the initiating UE, UEX 602, such as session ID and PRS resources, including frequency channels and timing instances, including the PRS broadcast time and the LBT hold time (or other delay time), and a PRS identifier (ID).

[0102] In Phase 1B, the second initiator UEY 604 sends a pre-PRS message to request a ranging session with the responder UEA 606. The pre-PRS message in Phase 1B follows the pre-PRS message in Phase 1A, and thus the ranging session initiated by the pre-PRS message in Phase 1A is sometimes referred to as the first ranging session, and the ranging session initiated by the pre-PRS message in Phase 1B is sometimes referred to as the second ranging session. Similar to Phase 1A, the pre-PRS message sent in Phase 1B may be transmitted via licensed spectrum and may indicate ranging signal attributes to be used by the responder UEA 606 (as well as the initiator UEY 604 and any other responder UE) in the second ranging session with the initiator UEY 604, such as session ID and PRS resources, including frequency channels and timing instances, the timing instances including PRS broadcast time and reserved LBT time (or other delay time), and a PRS identifier (ID).

[0103] In phase 2, responder UEA 606 determines whether there is a conflict between the first PRS and the second PRS assigned in the first PRS pre-message of phase 1A and the second PRS pre-message of phase 1B, respectively. For example, in... Figure 4 As discussed herein, a conflict can be determined if the PRS signals of two ranging sessions are assigned to the same channel and if the second PRS broadcast time is within a predetermined amount of time (e.g., a conflict threshold) of the first PRS broadcast time. The duration of the conflict threshold can be predetermined and, in some implementations, can be based on an approximate duration of the reserved LBT time (or other delay time). For example, the conflict threshold can be a percentage of the reserved LBT time associated with the first PRS broadcast (e.g., 100%, 80%, 60%, etc.). Other considerations and factors can be used to determine the duration of the conflict threshold. In some implementations, the responder UEA 606 can further determine the available time for the PRS broadcast, such as... Figure 4 As explained in the text. For example, available time can be determined based on the time before the first PRS broadcast time and after the LBT retention time or the conflict threshold time.

[0104] In Phase 3, in response to the PRS pre-request in Phase 1A, the responding UEA 606 sends a PRS pre-request message (ranging pre-request message) acknowledging receipt of the request to the first initiating UEX 602, thereby instructing the responding UEA 606 to accept the request for a ranging session from the initiating UEX 602. The PRS pre-request message in Phase 4A can be transmitted on licensed spectrum.

[0105] In Phase 4, in response to the PRS pre-request in Phase 1B, responding UEA 606 sends a PRS pre-request message (ranging pre-request message) to the second initiator UEA 604. Since the second PRS assigned in the second PRS pre-request message in Phase 1B conflicts with the first PRS assigned in the first PRS pre-request message in Phase 1A, the response PRS pre-request message in Phase 4 includes an indication of the PRS conflict, for example, using a negative acknowledgment (NACK) message. In some implementations, responding UEA 606 may include an indication of the available PRS broadcast time in the PRS pre-request message in Phase 4. For example, the indication of the available PRS broadcast time may be the start and end times of the available time, the start time and duration of the available time, the first PRS broadcast time, and optionally, a reserved LBT time or a conflict threshold duration, etc. The PRS pre-request message in Phase 4 may be transmitted on licensed spectrum.

[0106] As explained below, the initiator UEY 604 continues the second ranging session without reconstructing the second ranging session to avoid a PRS conflict for the responder UEA.

[0107] In Phase 5A, the first initiator UEX 602 broadcasts a PRS signal using the PRS resource set identified in the PRS pre-PRS message of Phase 1A. The PRS signal may be broadcast on unlicensed spectrum to utilize wideband. The first initiator UEX 602 records the Time of Distance (ToD) of the PRS signal and, in some implementations, records the AoD of the PRS signal, while the responder UEA 606 records the Time of A (ToA) of the PRS signal and, in some implementations, measures and records the AoA of the PRS signal.

[0108] In phase 5B, in response to receiving a PRS signal in phase 5A, responding UEA 606 uses the PRS resources (including frequency channel, PRS broadcast time, and LBT retention time) assigned in the PRS pre-PRS message of phase 1A to broadcast the PRS signal. The PRS signal may be broadcast on unlicensed spectrum to utilize wideband. Responding UEA 606 records the ToD of the PRS signal and, in some implementations, records the AoD of the PRS signal, while the first initiator UEX 602 records the ToA of the PRS signal and, in some implementations, measures and records the AoA of the PRS signal.

[0109] In Phase 6A, the second initiator UEY 604 broadcasts a PRS signal using the PRS resource set identified in the PRS pre-PRS message of Phase 1B. The PRS signal may be broadcast on unlicensed spectrum to utilize wideband. The second initiator UEY 604 records the ToD of the PRS signal and, in some implementations, records the AoD of the PRS signal, while the responder UEA 606 records the ToA of the PRS signal and, in some implementations, measures and records the AoA of the PRS signal.

[0110] In phase 6B, as illustrated by the dashed line, responder UEA 606 may broadcast a PRS signal (if possible, e.g., if the broadcast times of the PRS in phases 5B and 6B do not actually conflict). For example, if the PRS broadcast in phase 5B occurs before the scheduled broadcast time of the second PRS in phase 6B, responder UEA 606 may use the PRS resources (including frequency channels, revised PRS broadcast time, and reserved LBT time) assigned in the PRS pre-PRS message of phase 1B to broadcast the PRS signal; otherwise, responder UEA 606 will not broadcast a PRS signal. Initiator UEA 604 will then wait to receive the broadcast PRS signal. The PRS signal in phase 6B (if broadcast) may be broadcast on unlicensed spectrum to utilize wideband. If the PRS signal is broadcast, the responder UEA 606 records the ToD of the PRS signal and, in some implementations, records the AoD of the PRS signal, while the second initiator UEA 604 records the ToA of the PRS signal and, in some implementations, measures and records the AoA of the PRS signal.

[0111] In phase 7A, the first initiator UEX 602 sends a post-PRS message to the responder UEA 606. This post-PRS message indicates the Time of Docking (ToD) of the PRS signal broadcast in phase 5A, and in some implementations, indicates the Area of ​​Docking (AoD) of the PRS signal broadcast in phase 5A, and indicates the Time of ApoA of the PRS signal received in phase 5B, and in some implementations, indicates the Area of ​​ApoA of the PRS signal received in phase 5B. If the location of the first initiator UEX 602 is known, the post-PRS message may further include the current location of the first initiator UEX 602.

[0112] In phase 7B, responder UEA 606 sends a post-PRS message to first initiator UEX 602. This post-PRS message indicates the ToA of the PRS signal received in phase 5A, and in some implementations, indicates the AoA of the PRS signal received in phase 5A, and indicates the ToD of the PRS signal broadcast in phase 5B, and in some implementations, indicates the AoD of the PRS signal broadcast in phase 5B. If the location of responder UEA 606 is known, the post-PRS message may further include the current location of responder UEA 606.

[0113] In phase 8A, the second initiator UEY 604 may send a post-PRS message to the responder UEA 606. This post-PRS message indicates the ToD of the PRS signal broadcast in phase 6A, and in some implementations, indicates the AoD of the PRS signal broadcast in phase 6A. It also indicates whether the PRS was received in phase 6B, and if so, indicates the ToA of the PRS signal received in phase 6B, and in some implementations, indicates the AoA of the PRS signal received in phase 6B. If the location of the second initiator UEY 604 is known, the post-PRS message may further include the current location of the second initiator UEY 604.

[0114] In phase 8B, responder UEA 606 may send a post-PRS message to second initiator UEA 604. This post-PRS message indicates the ToA of the PRS signal received in phase 6A, and in some implementations, indicates the AoA of the PRS signal received in phase 6A. It also indicates whether the PRS was broadcast in phase 6B, and if so, indicates the ToD of the PRS signal broadcast in phase 6B, and in some implementations, indicates the AoD of the PRS signal broadcast in phase 6B. If the location of responder UEA 606 is known, the post-PRS message may further include the current location of responder UEA 606.

[0115] In phase 9A, the first initiator UEX 602 may determine the range between UEX 602 and the responder UEA 606 based on the ToD and ToA of the PRS signal broadcast in phases 5A and 5B. For example, this range may be based on the PRS signal. i The ToDi and ToAi of the signal (where i = 1 for a PRS broadcast by the initiator UEX 602 and i = 2 for a PRS broadcast by the responder UEA 606) are determined as follows:

[0116]

[0117] If the location of responder UE 606 is known, for example, in the PRS post-message in phase 7B along with additional information (such as the AoA or AoD of the PRS signal or other responder UEs) Figure 6 If the location and range (not shown) or geographic information (such as street location) are provided together, the location of the initiator UEX 602 can be determined using, for example, multilateral positioning and constraints based on the AoA or AoD of the PRS signal and geographic information.

[0118] In phase 9B, as illustrated by the dashed lines, if respondent UEA broadcasts a PRS in phase 6B, then second initiator UEY 604 can determine the range between UEY 604 and respondent UEA 606 based on the ToD and ToA of the PRS signal broadcast in phases 6A and 6B, in a manner similar to that described in phase 9A. The location of initiator UEY 604 can also be determined in a manner similar to that described in phase 9A. If respondent UEA 606 does not broadcast a PRS in phase 6B, then the range between UEY 604 and respondent UEA 606 is not determined, and the location of second initiator UEY 604 will need to be determined without using the distance to respondent UEA 606.

[0119] In phase 9C, responder UEA 606 may determine the range between UEA 606 and the first initiator UEX 602 based on the ToA and ToD of the PRS signals broadcast in phases 5A and 5B and in phases 6A and 6B, respectively, in a manner similar to that described in phases 9A and 9B, and determine the range between UEA 606 and the second initiator UEY 604 if responder UEA broadcasts a PRS in phase 6B. The location of responder UEA 606 may also be determined, for example, based on the location of the first initiator UEX 602 or the second initiator UEY 604 (if provided at phases 7A and 7B), in a manner similar to that described in phase 9A. If responder UEA 606 does not broadcast PRS in phase 6B, the range between responder UEA 606 and second initiator UEY 604 is not determined, and the location of responder UEA 606 will need to be determined without using the range of second initiator UEY 604.

[0120] Figure 7 A schematic block diagram illustrating certain exemplary features of a user equipment (UE) 700 is shown, which UE 700 may be as follows: Figure 1 The UE, RSU 110 in the vehicle 102 or 104 described herein, or UE 112 held by the pedestrian 114.

[0121] UE 700 can be configured to act as an initiating UE (e.g., UEY) or a responding UE (e.g., UEA) during a ranging session, as discussed herein. If UE 700 is a V-UE, it can be configured to control the autopilot of a vehicle (e.g., vehicle 102). For example, UE 700 may include a vehicle interface 705 through which commands for autopilot are provided to the vehicle, and perception inputs including speed and acceleration can be provided from the vehicle to UE 700. For example, UE 700 may include one or more processors 702; memory 704; an inertial measurement unit (IMU) 707, such as an accelerometer, gyroscope, magnetometer, etc., for detecting orientation relative to a global or local reference frame and motion or one or more motion characteristics of a vehicle; a satellite positioning system (SPS) receiver 709 for determining, for example, GPS positioning; and external interfaces including, for example, a wireless wide area network (WWAN) transceiver 710 and a wireless local area network (WLAN) transceiver 714, which are operatively coupled to a non-transient computer-readable medium 720 and memory 704 via one or more connections 706 (e.g., bus, line, fiber optic, link, etc.). UE 700 may further include additional items not shown, such as a user interface by which a user can interface with a user equipment, which may include, for example, a display, keypad, or other input devices (such as a virtual keypad on a display). In some example implementations, all or part of UE 700 may take the form of a chipset, etc.

[0122] The transceiver 710 can be, for example, a cellular transceiver, which can be configured to transmit and receive direct communication in a wireless network, such as... Figure 1 As explained herein, transceiver 710 may include a transmitter 711 implemented to transmit one or more signals over one or more types of wireless communication networks, and a receiver 712 to receive one or more signals transmitted over such wireless communication networks. Transceiver 714 may be, for example, a short-range transceiver and may be configured to transmit and receive direct communication in a wireless network, such as... Figure 1 As explained in the document, transceiver 714 may include a transmitter 715 implemented to transmit one or more signals (including ranging signals (PRS signals) and pre-ranging (PRS) and post-ranging (PRS) messages, as well as combination and splitting messages) over one or more types of wireless communication networks, and a receiver 716 to receive one or more signals (e.g., including PRS and pre-PRS and post-PRS messages, combination and splitting messages) transmitted over such one or more types of wireless communication networks. Transceivers 710 and 714 enable UE 700 to communicate with transport entities using D2D communication links such as DSRC, C-V2X, or 5G NR.

[0123] In some embodiments, the UE 700 may include an antenna 709, which may be internal or external. The antenna 709 may be used to transmit and / or receive signals processed by transceiver 710 and / or transceiver 714. In some embodiments, the antenna 709 may be coupled to transceiver 710 and / or transceiver 714. In some embodiments, measurements of signals received (transmitted) by the UE 710 may be performed at the connection point between the antenna 709 and transceiver 710 and / or transceiver 714. For example, a measurement reference point for measuring the received (transmitted) RF signal may be an input (output) terminal of receivers 712, 716 (transmitters 711, 715) and an output (input) terminal of antenna 709. In a UE 700 having multiple antennas 709 or an antenna array, the antenna connector may be considered as a virtual point representing the aggregated output (input) of multiple antennas. The phase difference of the received signals at multiple antennas or antenna arrays can be used to determine the AoA of the signal relative to the antenna array, which can be converted to a local or global reference frame based on the known orientation of the UE 700 (e.g., based on the orientation of the UE 700 relative to a global or local reference frame as measured by the IMU 707).

[0124] One or more processors 702 may be implemented using a combination of hardware, firmware, and software. For example, one or more processors 702 may be configured to perform the functions discussed herein by implementing one or more instructions or program code 708 on a non-transient computer-readable medium, such as medium 720 and / or memory 704. In some embodiments, one or more processors 702 may represent one or more circuits that may be configured to perform at least a portion of a data signal calculation procedure or process related to the operation of UE 700.

[0125] Medium 720 and / or memory 704 may store instruction or program code 708 containing executable code or software instructions that, when executed by one or more processors 702, cause those processors 702 to operate as a dedicated computer programmed to perform the techniques disclosed herein. As explained in UE 700, medium 720 and / or memory 704 may include one or more components or modules that may be implemented by one or more processors 702 to perform the methodologies described herein. Although each component or module is described as software in medium 720 executable by the one or more processors 702, it should be understood that each component or module may be stored in memory 704 or may be dedicated hardware in or outside of one or more processors 702.

[0126] Several software modules and data tables may reside in medium 720 and / or memory 704 and be utilized by one or more processors 702 to manage both the communication and functionality described herein. It should be understood that the organization of the contents of medium 720 and / or memory 704 as shown in UE 700 is merely exemplary, and thus, the functionality of the individual modules and / or data structures may be combined, separated, and / or constructed in different ways depending on the implementation of UE 700.

[0127] The medium 720 and / or memory 704 may include a ranging module 721, which, when implemented by one or more processors 702, configures one or more processors 702 to participate in a ranging session as an initiating UE or a responding UE, as discussed herein. For example, the ranging module 721 may include a pre-ranging module (PRS pre-message module 722), a ranging signal module (PRS module 724), a post-ranging module (PRS post-message module 726), and a ranging module 728.

[0128] Medium 720 and / or memory 704 may include a PRS pre-processor module 722, which, when implemented by one or more processors 702, configures one or more processors 702 to generate and transmit or receive pre-ranging messages (such as PRS pre-processor messages) via transceiver 714, for example, to initiate or accept a ranging session. PRS pre-processor messages may be broadcast, multicast, or unicast (via an RRC connection). In some implementations, PRS messages may be transmitted and received on licensed spectrum. A PRS pre-processor message may be an initiating PRS pre-processor message for initiating a ranging session or a responding PRS pre-processor message for acknowledging an initiating PRS pre-processor message or indicating a PRS conflict with another ranging session (e.g., using a negative acknowledgment (NACK) message). PRS pre-processor messages may include identifiers for locating the initiating UE and one or more responding UEs of the session, which may be monitored by UE 700 over multiple ranging sessions. Participating UEs may be determined, for example, based on capability messages received by UE 700 or by monitoring PRS pre-processor messages broadcast by multiple initiating UEs over a time period. A PRS pre-message message may include a session ID and ranging signal resources for participating UEs, including the time and frequency for the responding UE to broadcast ranging (PRS) signals in the ranging session, the PRS ID, etc. For example, the time resource may be the PRS broadcast time and the reserved LBT time (e.g., the maximum LBT time) or another delay time. A response PRS pre-message message from the responding UE indicating a PRS conflict with another ranging session may further include available PRS broadcast time.

[0129] Medium 720 and / or memory 704 may include a PRS module 724, which, when implemented by one or more processors 702, configures one or more processors 702 to broadcast and receive ranging signals from other UEs in ranging via transceiver 714, as discussed herein. For example, the ranging signal may be a PRS signal, such as a sequence of pseudo-noise (PN) modulated by quadrature phase shift keying (QPSK) as discussed herein. The ranging signal may be broadcast using a PRS identifier at a frequency indicated by a pre-PRS message during an assigned broadcast time (e.g., after an LBT procedure using a reserved LBT time). The ranging signal may be broadcast and received on unlicensed spectrum and may be broadcast according to Category 2 or Category 4 LBT constraints. One or more processors 702 may, for example, be configured to measure the ToD of the broadcast ranging signal and the ToA of the received ranging signal, and may be configured to measure the AoD of the broadcast ranging signal and the AoA of the received ranging signal.

[0130] The medium 720 and / or memory 704 may include a PRS post-message module 726, which, when implemented by one or more processors 702, configures one or more processors 702 to send and receive post-range messages to other UEs in ranging via transceiver 714, as discussed herein. The PRS post-message may include, for example, an indication of ToD for a broadcast ranging signal and, in some implementations, an indication of AoD, and an indication of ToA for a received ranging signal and, in some implementations, an indication of AoA. In some implementations, the indications of ToD and ToA may be the difference between ToD and ToA. In some implementations, the PRS post-message may include an indication of the UE's location, for example, if the UE is an anchor UE used to locate another UE.

[0131] The medium 720 and / or memory 704 may include a ranging module 728, which, when implemented by one or more processors 702, configures the one or more processors 702 to determine the range to another UE based on broadcast ranging signals, such as those measured by UE 700 and received from other UEs in a PRS post-message, and the ToD and ToA of the received ranging signals.

[0132] The medium 720 and / or memory 704 may include a positioning module 730, which, when implemented by one or more processors 702, is configured to determine the location of the UE 700 based on one or more ranges to the broadcast UE and their location information, for example, using multilateral positioning or other appropriate techniques discussed herein. For example, one or more processors 702 may implement a Kalman filter or an extended Kalman filter to determine the location of the UE 700.

[0133] The medium 720 and / or memory 704 may include a conflict module 732, which, when implemented by one or more processors 702, configures one or more processors 702 to determine whether a PRS conflict exists in multiple ranging sessions. The conflict may be determined based on the PRS of two separate ranging sessions using the same time and frequency resources. For example, one or more processors 702 may be configured to determine that a conflict exists between a first PRS signal and a second PRS signal if the time for broadcasting a second PRS signal is within a predetermined amount of time from the time for broadcasting a first PRS signal. For example, the predetermined amount of time may be a predetermined maximum waiting time or a predetermined conflict threshold time of the LBT protocol, such as... Figure 4 As discussed in the article.

[0134] The medium 720 and / or memory 704 may include an available broadcast time 734, which, when implemented by one or more processors 702, configures one or more processors 702 to determine an available time for the responding UE to broadcast a PRS when a PRS collision has been detected. For example, when a collision between a first PRS signal and a second PRS signal has been detected, the available time for broadcasting the second PRS signal may be determined based on the time used to broadcast the first PRS signal. For example, the available time for broadcasting may be determined based on a predetermined maximum waiting time of the LBT procedure or based on a predetermined collision threshold time, for example, as... Figure 4 As discussed in [the document]. If UE 700 is the initiating UE, one or more processors 702 can be configured to determine the available time for the responding UE to broadcast the PRS based on the available time for broadcasting received from the responding UE in the PRS pre-message. If no available time for broadcasting is received from the responding UE, one or more processors 702 can be configured to determine the available time for the responding UE to broadcast the PRS based on the initial broadcast time of the PRS signal and a predetermined time period. For example, the predetermined time period can be based on the maximum waiting time of the LBT procedure used to broadcast the PRS signal or a predetermined conflict threshold time period.

[0135] The methodologies described herein can be implemented through various means depending on the application. For example, these methodologies can be implemented in hardware, firmware, software, or any combination thereof. For hardware implementation, the one or more processors 702 can be implemented within one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, electronic devices, other electronic units designed to perform the functions described herein, or combinations thereof.

[0136] For firmware and / or software implementations, these methodologies can be implemented using modules (e.g., procedures, functions, etc.) that perform the functions described herein. Any machine-readable medium that tangibly embodies instructions can be used to implement the methodologies described herein. For example, software code can be stored in a non-transient computer-readable medium 720 or memory 704 connected to and executed by one or more processors 702. Memory can be implemented within or outside of the one or more processors. As used herein, the term "memory" means any type of long-term, short-term, volatile, non-volatile, or other memory, and is not limited to any particular type or number of memories, or the type of medium on which memory is stored.

[0137] If implemented in firmware and / or software, the functionality may be stored as one or more instructions or program code 708 on a non-transient computer-readable medium (such as medium 720 and / or memory 704). Examples include computer-readable media encoding data structures and computer-readable media encoding computer programs 708. For example, a non-transient computer-readable medium including program code 708 stored thereon may include program code 1208 for supporting multiple ranging sessions, including determining the existence of a PRS conflict and providing an indication to the initiating UE (which may initiate a new ranging session based on the available PRS broadcast time of the responding UE), in a manner consistent with the disclosed embodiments. The non-transient computer-readable medium 720 includes a physical computer storage medium. The storage medium may be any available medium accessible to a computer. By way of example and not limitation, such non-transient computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage, or other magnetic storage devices, or any other medium that can be used to store desired program code 708 in the form of instructions or data structures and that can be accessed by a computer; as used herein, disk and disc include compact discs (CDs), laser discs, optical discs, digital multi-purpose discs (DVDs), floppy disks, and Blu-ray discs, wherein disks often magnetically reproduce data, while discs optically reproduce data using lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0138] In addition to being stored on the computer-readable medium 720, instructions and / or data may also be provided as signals included on a transmission medium in a communication apparatus. For example, a communication apparatus may include a transceiver 710 having signals indicating instructions and data. These instructions and data are configured to cause one or more processors to perform the functions outlined in the claims. That is, the communication apparatus includes a transmission medium having signals indicating information for performing the disclosed functions.

[0139] Memory 704 can represent any data storage device. Memory 704 may include, for example, main memory and / or secondary memory. Main memory may include, for example, random access memory, read-only memory, etc. Although described in this example as separate from one or more processors 702, it should be understood that all or part of the main memory may be located within one or more processors 702 or otherwise co-located / coupled with one or more processors 702. Secondary memory may include, for example, memory of the same or similar type as the main memory and / or one or more data storage devices or systems (such as, for example, disk drives, optical disk drives, tape drives, solid-state drives, etc.).

[0140] In some implementations, secondary memory may be operatively accommodated or otherwise configured to be coupled to non-transient computer-readable medium 720. Thus, in some example implementations, the methods and / or apparatus presented herein may take the form of a computer-readable medium 720 that may include all or a portion of computer-readable code 708 stored thereon, which, when executed by one or more processors 702, may be operatively implemented to perform all or a portion of the example operations as described herein. Computer-readable medium 720 may be part of memory 704.

[0141] Figure 8 This explains the role of responding UEs (such as...) in a distributed system of User Equipment (UE). Figure 3 , 5 UEA in 6, or Figure 7 The flowchart 800 shows the method for performing ranging in UE 700.

[0142] In box 802, the responding UE receives a first ranging pre-request message from the first initiating UE to initiate a first ranging session. The first ranging pre-request message includes first ranging signal resources, which include the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session, for example, as in... Figure 5 and 6 The first ranging request message, which is discussed in Phase 1A, is an apparatus for receiving a first ranging pre-request message from a first initiating UE to initiate a first ranging session. The first ranging pre-request message includes a first ranging signal resource, which includes the time and frequency for the responding UE to broadcast a first ranging signal in the first ranging session. The apparatus may be, for example, a transceiver 714 and one or more processors 702 having dedicated hardware or executable code or software instructions (such as ranging module 721 and PRS pre-message module 722) in memory 704 and / or medium 720.

[0143] In box 804, the responding UE receives a second ranging pre-request message from the second initiating UE, indicating a intention to initiate a second ranging session. The second ranging pre-request message includes second ranging signal resources, which include the time and frequency for the responding UE to broadcast the second ranging signal during the second ranging session, for example, as in... Figure 5 and 6 The second ranging pre-request message, as discussed in Phase 1B, is an apparatus for receiving a second ranging pre-request message from a second initiating UE to initiate a second ranging session. The second ranging pre-request message includes second ranging signal resources, which include the time and frequency for the responding UE to broadcast a second ranging signal in the second ranging session. This apparatus may be, for example, a transceiver 714 and one or more processors 702 having dedicated hardware or executable code or software instructions (such as ranging module 721 and PRS pre-message module 722) in memory 704 and / or medium 720.

[0144] In block 806, the responding UE determines a conflict between the first ranging signal and the second ranging signal based on the first ranging signal resource and the second ranging resource, for example, as in... Figure 5 and 6 The apparatus for determining a conflict between a first ranging signal and a second ranging signal based on a first ranging signal resource and a second ranging resource may be, for example, one or more processors 702 having dedicated hardware or implementing executable code or software instructions (such as a conflict module 732) in memory 704 and / or medium 720.

[0145] In box 808, the responding UE sends a first pre-ranging response message to the first initiating UE, acknowledging receipt of the first pre-ranging request message, for example, as in... Figure 5 and 6 The apparatus for sending a first pre-ranging response message to the first initiating UE confirming receipt of the first pre-ranging request message may be, for example, a transceiver 714 and one or more processors 702 having dedicated hardware or executable code or software instructions (such as ranging module 721 and PRS pre-message module 722) in memory 704 and / or medium 720.

[0146] In block 810, the responding UE sends a second ranging pre-response message to the second initiating UE, indicating a conflict with the second ranging signal resource used for the second ranging signal, for example, as in... Figure 5 and 6The means for sending a second ranging pre-response message indicating a conflict with the second ranging signal resource used for the second ranging signal, as discussed in stage 4, may be, for example, a transceiver 714 and one or more processors 702 having dedicated hardware or executable code or software instructions (such as ranging module 721, PRS pre-message module 722, and conflict module 732) in memory 704 and / or medium 720.

[0147] As an example, in some implementations, the responding UE can determine the conflict between the first ranging signal and the second ranging signal by determining that the time for broadcasting the second ranging signal is within a predetermined amount of time for broadcasting the first ranging signal, for example, as in Figure 4 China and Figure 5 and 6 This is discussed in stage 2. For example, the predetermined time amount could be a predetermined maximum waiting time for the listen-before-transmit procedure used to broadcast the second ranging signal. In another example, the predetermined time amount could be a predetermined collision threshold time. The means for determining that the time for broadcasting the second ranging signal is within the predetermined time amount for broadcasting the first ranging signal could be, for example, one or more processors 702 having dedicated hardware or implementing executable code or software instructions (such as collision module 732) in memory 704 and / or medium 720. Additionally, the responding UE can determine the collision between the first and second ranging signals by determining that the frequency used to broadcast the second ranging signal is the same as the frequency used to broadcast the first ranging signal, for example, as in Figure 4 China and Figure 5 and 6 The means for determining that the frequency used to broadcast the second ranging signal is the same as the frequency used to broadcast the first ranging signal may be, for example, one or more processors 702 having dedicated hardware or implementing executable code or software instructions (such as conflict module 732) in memory 704 and / or medium 720.

[0148] In some implementations, the responding UE may further determine the available time for broadcasting the second ranging signal, wherein the pre-ranging response message includes the available time for broadcasting the second ranging signal, for example, as in Figure 4 China and Figure 5 and 6The available time for broadcasting the second ranging signal may be based on the time included in the first ranging signal resource for broadcasting the first ranging signal. In one example, the available time for broadcasting the second ranging signal may be further based on a predetermined maximum waiting time of the listen-before-transmit procedure for broadcasting the first ranging signal. In another example, the available time for broadcasting the second ranging signal may be further based on a predetermined collision threshold time. The means for determining the available time for broadcasting the second ranging signal, wherein the second ranging pre-response message includes the available time for broadcasting the second ranging signal, may be, for example, one or more processors 702 having dedicated hardware or implementing executable code or software instructions (such as the available broadcast time module 734) in memory 704 and / or medium 720.

[0149] In one implementation, the responding UE may receive a third ranging pre-request message from the second initiating UE, indicating that a second ranging session is to be initiated. The third ranging pre-request message includes third ranging signal resources, which include the time and frequency for the responding UE to broadcast the second ranging signal during the second ranging session, for example, as in... Figure 5 The process discussed in stage 6 of the protocol includes means for receiving a third ranging pre-request message from a second initiating UE to initiate a second ranging session. The third ranging pre-request message includes third ranging signal resources, which include the time and frequency for the responding UE to broadcast a second ranging signal in the second ranging session. This means may be, for example, a transceiver 714 and one or more processors 702 having dedicated hardware or executable code or software instructions (such as ranging module 721 and PRS pre-message module 722) in memory 704 and / or medium 720. The responding UE may perform a first ranging session with the first initiating UE, which includes broadcasting a first ranging signal according to the first ranging signal resources, for example, as in... Figure 5 The second ranging session, discussed in phase 8B, can be performed with the second initiating UE, including broadcasting a second ranging signal based on a third ranging signal resource, for example, as in Figure 5 The apparatus discussed in phase 9B is for performing a first ranging session with a first initiating UE, including broadcasting a first ranging signal according to a first ranging signal resource, and for performing a second ranging session with a second initiating UE, including broadcasting a second ranging signal according to a third ranging signal resource. This may be, for example, a transceiver 714 and one or more processors 702 having dedicated hardware or executable code or software instructions (such as ranging module 721 and PRS module 724) in memory 704 and / or medium 720.

[0150] Figure 9 This explains the role of the initiating UE (such as...) in a distributed system of User Equipment (UE). Figure 3 ,5 UEY in 6, or Figure 7 The flowchart 900 shows the method for performing ranging in UE 700.

[0151] In box 902, the initiating UE transmits a first ranging pre-request message to the responding UE to initiate a first ranging session. The first ranging pre-request message includes first ranging signal resources, which include the time and frequency for the responding UE to broadcast a first ranging signal during the first ranging session, for example, as in... Figure 5 and 6 The first ranging request message, as discussed in Phase 1B, is a means for transmitting a first ranging pre-request message to a responding UE to initiate a first ranging session. The first ranging pre-request message includes first ranging signal resources, which include the time and frequency for the responding UE to broadcast a first ranging signal in the first ranging session. This means may be, for example, a transceiver 714 and one or more processors 702 having dedicated hardware or executable code or software instructions (such as ranging module 721 and PRS pre-message module 722) in memory 704 and / or medium 720.

[0152] In block 904, the initiating UE receives a first pre-ranging response message from the responding UE. This first pre-ranging response message indicates a conflict between a first ranging signal resource used for a first ranging signal and a second ranging signal resource used for a second ranging signal for a second initiating UE, for example, as in... Figure 5 and 6 The apparatus discussed in stage 4 of the above. The means for receiving a first ranging pre-response message from a responding UE, the first ranging pre-response message indicating a conflict between a first ranging signal resource for a first ranging signal and a second ranging signal resource for a second ranging signal for a second initiating UE, may be, for example, a transceiver 714 and one or more processors 702 having dedicated hardware or executable code or software instructions (such as ranging module 721 and PRS pre-message module 722) in memory 704 and / or medium 720.

[0153] In some implementations, the initiating UE can further determine the available time for the responding UE to broadcast the first ranging signal, for example, as in Figure 4 China and Figure 5This is discussed in stage 5. For example, the first pre-ranging response message may include an available time for the responding UE to broadcast the first ranging signal. In another example, the available time for the responding UE to broadcast the first ranging signal may be based on the time included in the first ranging signal resource for broadcasting the first ranging signal and a predetermined time period. For example, the predetermined time period may be based on the maximum waiting time of the listen-before-transmit procedure for broadcasting the first ranging signal or a predetermined conflict threshold time period. The means for determining the available time for the responding UE to broadcast the first ranging signal may be, for example, one or more processors 702 having dedicated hardware or implementing executable code or software instructions (such as the available broadcast time module 734) in memory 704 and / or medium 720. The initiating UE may transmit a second pre-ranging request message to the responding UE to initiate a first ranging session. The second pre-ranging request message includes a third ranging signal resource, which includes the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session based on the available time, for example, as in Figure 5 The second ranging pre-request message, as discussed in stage 6, is used to transmit a second ranging pre-request message to the responding UE to initiate a first ranging session. This second ranging pre-request message includes a third ranging signal resource, which, based on the available time, includes the time and frequency for the responding UE to broadcast a first ranging signal in the first ranging session. This resource may be, for example, one or more processors 702 having dedicated hardware or implementing executable code or software instructions (such as ranging module 721 and PRS pre-message module 722) in memory 704 and / or medium 720.

[0154] In some implementations, the initiating UE may further receive a second pre-ranging response message from the responding UE acknowledging receipt of the second pre-ranging request message, for example, as in... Figure 5 The phase discussed in stage 7, and the ability to perform a first ranging session with the responding UE, includes: receiving a first ranging signal transmitted by the responding UE according to a third ranging signal resource, for example, as in Figure 5 The means for receiving a second ranging pre-response message acknowledging receipt of a second ranging pre-request message from the responding UE may be, for example, a transceiver 714 and one or more processors 702 having dedicated hardware or implementing executable code or software instructions (such as ranging module 721 and PRS pre-message module 722) in memory 704 and / or medium 720. The means for performing a first ranging session with the responding UE, including receiving a first ranging signal transmitted by the responding UE according to a third ranging signal resource, may be, for example, a transceiver 714 and one or more processors 702 having dedicated hardware or implementing executable code or software instructions (such as ranging module 721 and PRS module 724) in memory 704 and / or medium 720.

[0155] In some implementations, the initiating UE can initiate a first ranging session with the responding UE by transmitting an initial ranging signal and waiting to receive a first ranging signal transmitted by the responding UE according to a first ranging signal resource, for example, as in Figure 6 The apparatus discussed in stages 6A and 6B is for performing a first ranging session with a responding UE, comprising transmitting an initial ranging signal and waiting to receive a first ranging signal transmitted by the responding UE according to a first ranging signal resource. It may be, for example, a transceiver 714 and one or more processors 702 having dedicated hardware or executable code or software instructions (such as ranging module 721 and PRS module 724) in memory 704 and / or medium 720.

[0156] Throughout this specification, the terms "an example," "an example," "some examples," or "exemplary implementation" mean that a particular feature, structure, or characteristic described in conjunction with a feature and / or example may be included in at least one feature and / or example of the claimed subject matter. Therefore, phrases appearing throughout the specification such as "an example," "an example," "some examples," or "in some implementations," or other similar phrases, do not necessarily all refer to the same feature, example, and / or limitation. Furthermore, these particular features, structures, or characteristics may be combined in one or more examples and / or features.

[0157] Some portions of the detailed descriptions included herein are presented in the form of algorithms or symbolic representations of operations on binary digital signals stored in the memory of a particular device or dedicated computing device or platform. In the context of this particular specification, the term "specific device," etc., once programmed to perform a specific operation according to instructions from program software, includes a general-purpose computer. Algorithm descriptions or symbolic representations are examples of techniques used by those skilled in the art of signal processing or related fields to convey the essence of their work to others skilled in the art. Here, an algorithm is generally considered to be a self-consistent sequence of operations or similar signal processing that leads to a desired result. In this context, the operation or processing involves the physical manipulation of physical quantities. Typically, but not necessarily, such quantities may take the form of electrical or magnetic signals that can be stored, transmitted, combined, compared, or otherwise manipulated. It has proven convenient at times to refer to such signals as bits, data, values, elements, symbols, characters, items, numbers, numerical values, etc., primarily for reasons of general use. However, it should be understood that all such terms, or similar terms, are to be associated with the appropriate physical quantity and are merely convenient labels. Unless otherwise specifically stated, as will be apparent from the discussion herein, throughout this specification, the use of terms such as “processing,” “calculating,” “determining,” and “determining” refers to the actions or processes of a particular device (such as a dedicated computer, dedicated computing device, or similar dedicated electronic computing device). In the context of this specification, therefore, a dedicated computer or similar dedicated electronic computing device is capable of manipulating or transforming signals that are generally represented as physical electronic or magnetic quantities within the memory, registers, or other information storage, transmission, or display devices of such dedicated computer or similar dedicated electronic computing device.

[0158] In the detailed description above, numerous specific details have been set forth to provide a thorough understanding of the claimed subject matter. However, those skilled in the art will understand that the claimed subject matter can be practiced without these specific details. In other instances, methods and apparatus known to those of ordinary skill in the art have not been described in detail to avoid obscuring the claimed subject matter.

[0159] As used herein, the terms “and,” “or,” and “and / or” may include a variety of meanings, which are also contemplated, at least in part, depending on the context in which such terms are used. Generally, “or,” when used to relate a list such as A, B, or C, is intended to mean A, B, and C (in the inclusive sense) and A, B, or C (in the exclusive sense). Additionally, the term “one or more” as used herein may be used to describe any feature, structure, or characteristic in the singular form, or may be used to describe multiple features, structures, or characteristics, or some other combination thereof. However, it should be noted that this is merely an illustrative example, and the claimed subject matter is not limited to this example.

[0160] While the features currently considered exemplary have been explained and described, those skilled in the art will understand that various other modifications can be made and equivalents can be substituted without departing from the claimed subject matter. Furthermore, numerous modifications can be made to adapt a particular scenario to the teachings of the claimed subject matter without departing from the central concepts described herein.

[0161] Examples of implementations are described in the following numbered clauses:

[0162] 1. A method for ranging between UEs performed by a responding user equipment (UE), the method comprising:

[0163] The first initiating UE receives a first ranging pre-request message to initiate a first ranging session. The first ranging pre-request message includes a first ranging signal resource. The first ranging signal resource includes the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session.

[0164] The second initiating UE receives a second ranging pre-request message to initiate a second ranging session. The second ranging pre-request message includes second ranging signal resources. The second ranging signal resources include the time and frequency for the responding UE to broadcast the second ranging signal in the second ranging session.

[0165] The conflict between the first ranging signal and the second ranging signal is determined based on the first ranging signal resource and the second ranging resource;

[0166] Send a first pre-ranging response message to the first initiating UE acknowledging receipt of the first pre-ranging request message; and

[0167] Send a second ranging pre-response message to the second initiating UE, indicating a conflict with the second ranging signal resource used for the second ranging signal.

[0168] 2. The method of Clause 1, wherein determining the conflict between the first ranging signal and the second ranging signal comprises: determining that the time for broadcasting the second ranging signal is within a predetermined amount of time for broadcasting the first ranging signal.

[0169] 3. The method of Clause 2, wherein the predetermined time amount is the predetermined maximum waiting time for the listen-before-transmit procedure for broadcasting the second ranging signal.

[0170] 4. As in Clause 2, wherein the predetermined time amount is a predetermined conflict threshold time.

[0171] 5. The method of any of Clauses 2-4, wherein determining the conflict between the first ranging signal and the second ranging signal comprises: determining that the frequency used to broadcast the second ranging signal is the same as the frequency used to broadcast the first ranging signal.

[0172] 6. The method of any of Clauses 1-5, further comprising: determining an available time for broadcasting the second ranging signal, wherein the second ranging pre-response message includes the available time for broadcasting the second ranging signal.

[0173] 7. The method of Clause 6, wherein the available time for broadcasting the second ranging signal is based on the time for broadcasting the first ranging signal included in the first ranging signal resource.

[0174] 8. The method of Clause 7, wherein the available time for broadcasting the second ranging signal is further based on the predetermined maximum waiting time of the listen-before-transmit procedure for broadcasting the first ranging signal.

[0175] 9. The method of Clause 7, wherein the available time for broadcasting the second ranging signal is further based on a predetermined collision threshold time.

[0176] 10. The method of any of Clauses 1-9 further includes: receiving from the second initiating UE a third ranging pre-request message for initiating a second ranging session, the third ranging pre-request message including third ranging signal resources, the third ranging signal resources including the time and frequency for the responding UE to broadcast the second ranging signal in the second ranging session.

[0177] 11. The method as described in Clause 10, further comprising:

[0178] Performing a first ranging session with a first initiating UE, which includes broadcasting a first ranging signal based on a first ranging signal resource; and

[0179] Perform a second ranging session with the second initiating UE, which includes broadcasting a second ranging signal based on a third ranging signal resource.

[0180] 12. A responding UE configured to perform ranging between user equipment (UEs), the responding UE comprising:

[0181] A wireless transceiver configured to communicate wirelessly with entities in a wireless network;

[0182] At least one memory; and

[0183] At least one processor, coupled to the wireless transceiver and the at least one memory, wherein the at least one processor is configured to:

[0184] The first initiating UE receives a first ranging pre-request message to initiate a first ranging session. The first ranging pre-request message includes a first ranging signal resource. The first ranging signal resource includes the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session.

[0185] The second initiating UE receives a second ranging pre-request message to initiate a second ranging session. The second ranging pre-request message includes second ranging signal resources. The second ranging signal resources include the time and frequency for the responding UE to broadcast the second ranging signal in the second ranging session.

[0186] Based on the first ranging signal resource and the second ranging resource, determine the relationship between the first ranging signal and the second ranging signal.

[0187] Collisions between ranging signals;

[0188] Send the first pre-ranging response message to the first initiating UE confirming receipt of the first pre-ranging request message.

[0189] Information; and

[0190] Send a second ranging pre-response message to the second initiating UE, indicating a conflict with the second ranging signal resource used for the second ranging signal.

[0191] 13. The responding UE as described in Clause 12, wherein the at least one processor is configured to determine a conflict between the first ranging signal and the second ranging signal by being configured to perform the following operation: determining that the time for broadcasting the second ranging signal is within a predetermined amount of time for broadcasting the first ranging signal.

[0192] 14. The responding UE as in Clause 13, wherein the predetermined time amount is the predetermined maximum waiting time for the listen-before-transmit procedure for broadcasting the second ranging signal.

[0193] 15. As in Clause 13, the responding UE, where the predetermined time amount is the predetermined conflict threshold time.

[0194] 16. The UE responding to any of the provisions 13-15, wherein the at least one processor is configured to determine the conflict between the first ranging signal and the second ranging signal by being configured to perform the following operation: determining that the frequency used to broadcast the second ranging signal is the same as the frequency used to broadcast the first ranging signal.

[0195] 17. The responding UE of any of Clauses 12-16, wherein the at least one processor is further configured to: determine an available time for broadcasting the second ranging signal, wherein the second ranging pre-response message includes the available time for broadcasting the second ranging signal.

[0196] 18. The responding UE as in Clause 17, wherein the available time for broadcasting the second ranging signal is based on the time for broadcasting the first ranging signal included in the first ranging signal resource.

[0197] 19. The responding UE as in Clause 18, wherein the available time for broadcasting the second ranging signal is further based on a predetermined maximum waiting time for the listen-before-transmit procedure for broadcasting the first ranging signal.

[0198] 20. As in Clause 18, the available time for broadcasting the second ranging signal is further based on a predetermined collision threshold time.

[0199] 21. The responding UE of any of the provisions 12-20, wherein the at least one processor is further configured to: receive from the second initiating UE a third ranging pre-request message for initiating a second ranging session, the third ranging pre-request message including third ranging signal resources, the third ranging signal resources including the time and frequency for the responding UE to broadcast the second ranging signal in the second ranging session.

[0200] 22. The responding UE as described in Clause 21, wherein the at least one processor is further configured to:

[0201] A first ranging session is performed with the first initiating UE, which is configured to perform the following operations: broadcasting a first ranging signal based on a first ranging signal resource; and

[0202] A second ranging session is performed with the second initiating UE, which is configured to perform the following operation: broadcasting a second ranging signal based on a third ranging signal resource.

[0203] 23. A responding UE configured to perform ranging between user equipment (UEs), the responding UE comprising:

[0204] A means for receiving a first ranging pre-request message from a first initiating UE to initiate a first ranging session, the first ranging pre-request message including a first ranging signal resource, the first ranging signal resource including a time and frequency for the responding UE to broadcast a first ranging signal in the first ranging session;

[0205] A means for receiving a second ranging pre-request message from a second initiating UE to initiate a second ranging session, the second ranging pre-request message including second ranging signal resources, the second ranging signal resources including the time and frequency for the responding UE to broadcast a second ranging signal in the second ranging session;

[0206] A device for determining a conflict between a first ranging signal and a second ranging signal based on a first ranging signal resource and a second ranging resource;

[0207] A means for sending a first pre-ranging response message to a first initiating UE acknowledging receipt of a first pre-ranging request message; and

[0208] A means for sending a second ranging pre-response message to a second initiating UE indicating a conflict with a second ranging signal resource used for a second ranging signal.

[0209] 24. The responding UE as described in Clause 23, wherein the means for determining a conflict between the first ranging signal and the second ranging signal includes means for determining that the time for broadcasting the second ranging signal is within a predetermined amount of time for broadcasting the first ranging signal.

[0210] 25. The responding UE as in Clause 24, wherein the predetermined time amount is the predetermined maximum waiting time for the listen-before-transmit procedure for broadcasting the second ranging signal.

[0211] 26. As in Clause 24, the responding UE, where the predetermined time amount is the predetermined conflict threshold time.

[0212] 27. The UE responding to any of the provisions 24-26, wherein the means for determining the conflict between the first ranging signal and the second ranging signal includes means for determining that the frequency for broadcasting the second ranging signal is the same as the frequency for broadcasting the first ranging signal.

[0213] 28. The responding UE of any of the provisions 23-27 further includes: means for determining an available time for broadcasting the second ranging signal, wherein the second ranging pre-response message includes the available time for broadcasting the second ranging signal.

[0214] 29. The responding UE as in Clause 28, wherein the available time for broadcasting the second ranging signal is based on the time for broadcasting the first ranging signal included in the first ranging signal resource.

[0215] 30. The responding UE as in Clause 29, wherein the available time for broadcasting the second ranging signal is further based on a predetermined maximum waiting time for the listen-before-transmit procedure for broadcasting the first ranging signal.

[0216] 31. The responding UE as in Clause 29, wherein the available time for broadcasting the second ranging signal is further based on a predetermined conflict threshold time.

[0217] 32. The responding UE of any of the provisions 23-31 further includes: means for receiving from the second initiating UE a third ranging pre-request message for initiating a second ranging session, the third ranging pre-request message including third ranging signal resources, the third ranging signal resources including time and frequency for the responding UE to broadcast a second ranging signal in the second ranging session.

[0218] 33. As in Clause 32, the respondent UE further includes:

[0219] A means for performing a first ranging session with a first initiating UE, comprising broadcasting a first ranging signal according to a first ranging signal resource; and

[0220] A means for performing a second ranging session with a second initiating UE, comprising broadcasting a second ranging signal based on a third ranging signal resource.

[0221] 34. A non-transient storage medium including program code stored thereon, the program code being operable to configure at least one processor in a responding user equipment for ranging between UEs, the program code including instructions for the following operations:

[0222] The first initiating UE receives a first ranging pre-request message to initiate a first ranging session. The first ranging pre-request message includes a first ranging signal resource. The first ranging signal resource includes the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session.

[0223] The second initiating UE receives a second ranging pre-request message to initiate a second ranging session. The second ranging pre-request message includes second ranging signal resources. The second ranging signal resources include the time and frequency for the responding UE to broadcast the second ranging signal in the second ranging session.

[0224] The conflict between the first ranging signal and the second ranging signal is determined based on the first ranging signal resource and the second ranging resource;

[0225] Send a first pre-ranging response message to the first initiating UE acknowledging receipt of the first pre-ranging request message; and

[0226] Send a second ranging pre-response message to the second initiating UE, indicating a conflict with the second ranging signal resource used for the second ranging signal.

[0227] 35. The non-transient storage medium including program code as described in Clause 34, wherein the program code for determining a conflict between the first ranging signal and the second ranging signal includes: program code for determining that the time for broadcasting the second ranging signal is within a predetermined amount of time for broadcasting the first ranging signal.

[0228] 36. A non-transient storage medium including program code, as in Clause 35, wherein the predetermined time amount is the predetermined maximum waiting time for the listen-before-transmit procedure for broadcasting the second ranging signal.

[0229] 37. A non-transient storage medium including program code, as in Clause 35, wherein the predetermined time amount is a predetermined conflict threshold time.

[0230] 38. A non-transient storage medium comprising program code, such as any of Clauses 35-37, wherein the program code for determining a conflict between a first ranging signal and a second ranging signal comprises: program code for determining that the frequency used to broadcast the second ranging signal is the same as the frequency used to broadcast the first ranging signal.

[0231] 39. A non-transient storage medium including program code, such as any of clauses 34-38, further comprising: program code for determining an available time for broadcasting a second ranging signal, wherein the second ranging pre-response message includes the available time for broadcasting the second ranging signal.

[0232] 40. A non-transient storage medium including program code, as in Clause 39, wherein the available time for broadcasting the second ranging signal is based on the time for broadcasting the first ranging signal included in the first ranging signal resource.

[0233] 41. A non-transient storage medium including program code, as in Clause 40, wherein the available time for broadcasting the second ranging signal is further based on a predetermined maximum waiting time for the listen-before-transmit procedure for broadcasting the first ranging signal.

[0234] 42. A non-transient storage medium including program code, as in Clause 40, wherein the available time for broadcasting the second ranging signal is further based on a predetermined collision threshold time.

[0235] 43. The non-transient storage medium including program code of any of Clauses 34-42 further includes: program code for receiving a third ranging pre-request message from the second initiating UE to initiate a second ranging session, the third ranging pre-request message including third ranging signal resources, the third ranging signal resources including the time and frequency for the responding UE to broadcast a second ranging signal in the second ranging session.

[0236] 44. The non-transient storage medium including program code as described in Clause 43 further includes program code for the following operations:

[0237] Performing a first ranging session with a first initiating UE, which includes broadcasting a first ranging signal based on a first ranging signal resource; and

[0238] Perform a second ranging session with the second initiating UE, which includes broadcasting a second ranging signal based on a third ranging signal resource.

[0239] 45. A method for ranging between UEs performed by an initiating user equipment (UE), the method comprising:

[0240] The responding UE is sent a first ranging pre-request message to initiate a first ranging session. The first ranging pre-request message includes first ranging signal resources, which include the time and frequency for the responding UE to broadcast a first ranging signal during the first ranging session; and

[0241] The responding UE receives a first ranging pre-response message, which indicates a conflict between a first ranging signal resource used for a first ranging signal and a second ranging signal resource used for a second ranging signal for a second initiating UE.

[0242] 46. ​​The method as described in Clause 45 further includes:

[0243] Determine the available time for the responding UE to broadcast the first ranging signal; and

[0244] A second ranging pre-request message is transmitted to the responding UE to initiate a first ranging session. The second ranging pre-request message includes a third ranging signal resource, which includes the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session based on the available time.

[0245] 47. The method of Clause 46, wherein the first ranging pre-response message includes the available time for the responding UE to broadcast the first ranging signal.

[0246] 48. The method of any of Clauses 46-47, wherein the available time for the responding UE to broadcast the first ranging signal is based on the time for broadcasting the first ranging signal included in the first ranging signal resource and a predetermined time period.

[0247] 49. The method of Clause 48, wherein the predetermined time period is based on the maximum waiting time of the listen-before-transmit procedure for broadcasting the first ranging signal.

[0248] 50. The method of Clause 48, wherein the predetermined time period is a predetermined conflict threshold time period.

[0249] 51. The method of any of clauses 46-50 further includes:

[0250] The responding UE receives a second pre-ranging response message acknowledging receipt of the second pre-ranging request message; and

[0251] Performing a first ranging session with the responding UE includes: receiving a first ranging signal transmitted by the responding UE according to a third ranging signal resource.

[0252] 52. The method of Clause 45 further includes: performing a first ranging session with the responding UE, which includes: transmitting an initial ranging signal and waiting to receive a first ranging signal transmitted by the responding UE according to a first ranging signal resource.

[0253] 53. An initiating UE configured to perform ranging between user equipment (UEs), the initiating UE comprising:

[0254] A wireless transceiver configured to communicate wirelessly with entities in a wireless network;

[0255] At least one memory; and

[0256] At least one processor, coupled to the wireless transceiver and the at least one memory, wherein the at least one processor is configured to:

[0257] The responding UE is sent a first ranging pre-request message to initiate a first ranging session. The first ranging pre-request message includes first ranging signal resources, which include the time and frequency for the responding UE to broadcast a first ranging signal during the first ranging session; and

[0258] The responding UE receives a first ranging pre-response message, which indicates a conflict between a first ranging signal resource used for a first ranging signal and a second ranging signal resource used for a second ranging signal for a second initiating UE.

[0259] 54. As initiating UE in Clause 53, wherein the at least one processor is further configured to:

[0260] Determine the available time for the responding UE to broadcast the first ranging signal; and

[0261] A second ranging pre-request message is transmitted to the responding UE to initiate a first ranging session. The second ranging pre-request message includes a third ranging signal resource, which includes the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session based on the available time.

[0262] 55. As in the initiating UE of Clause 54, wherein the first ranging pre-response message includes the available time for the responding UE to broadcast the first ranging signal.

[0263] 56. The initiating UE of any of Clauses 54-55, wherein the available time for the responding UE to broadcast the first ranging signal is based on the time for broadcasting the first ranging signal included in the first ranging signal resource and a predetermined time period.

[0264] 57. As initiating UE under Clause 56, where the predetermined time period is based on the maximum waiting time of the listen-before-transmit procedure for broadcasting the first ranging signal.

[0265] 58. As in Article 56, the initiating UE, where the predetermined time period is the predetermined conflict threshold time period.

[0266] 59. The initiating UE of any of clauses 54-58, wherein the at least one processor is further configured to:

[0267] The responding UE receives a second pre-ranging response message acknowledging receipt of the second pre-ranging request message; and

[0268] Performing a first ranging session with the responding UE includes: receiving a first ranging signal transmitted by the responding UE according to a third ranging signal resource.

[0269] 60. The initiating UE as in Clause 53, wherein the at least one processor is configured to perform a first ranging session with the responding UE by transmitting an initial ranging signal and waiting to receive a first ranging signal transmitted by the responding UE in accordance with a first ranging signal resource.

[0270] 61. An initiating UE configured to perform ranging between user equipment (UEs), the initiating UE comprising:

[0271] A means for transmitting a first ranging pre-request message to a responding UE to initiate a first ranging session, the first ranging pre-request message including first ranging signal resources, the first ranging signal resources including a time and frequency for the responding UE to broadcast a first ranging signal in the first ranging session; and

[0272] A means for receiving a first ranging pre-response message from a responding UE, the first ranging pre-response message indicating a conflict between a first ranging signal resource for a first ranging signal and a second ranging signal resource for a second ranging signal for a second initiating UE.

[0273] 62. The UE that initiated Article 61 further includes:

[0274] A means for determining the available time for the responding UE to broadcast a first ranging signal; and

[0275] A means for transmitting a second ranging pre-request message to a responding UE to initiate a first ranging session, the second ranging pre-request message including a third ranging signal resource, the third ranging signal resource including, based on the available time, the time and frequency for the responding UE to broadcast a first ranging signal in the first ranging session.

[0276] 63. As in the initiating UE of Clause 62, wherein the first ranging pre-response message includes the available time for the responding UE to broadcast the first ranging signal.

[0277] 64. The initiating UE of any of Clauses 62-63, wherein the available time for the responding UE to broadcast the first ranging signal is based on the time for broadcasting the first ranging signal included in the first ranging signal resource and a predetermined time period.

[0278] 65. The initiating UE as in Clause 64, wherein the predetermined time period is based on the maximum waiting time of the listen-before-transmit procedure for broadcasting the first ranging signal.

[0279] 66. As in the initiating UE of Clause 64, where the predetermined time period is the predetermined conflict threshold time period.

[0280] 67. The initiating UE, such as any of the provisions 62-66, further includes:

[0281] A means for receiving a second pre-ranging response message from a responding UE acknowledging receipt of a second pre-ranging request message; and

[0282] A means for performing a first ranging session with a responding UE, comprising receiving a first ranging signal transmitted by the responding UE according to a third ranging signal resource.

[0283] 68. The initiating UE as described in Clause 61 further includes: means for performing a first ranging session with the responding UE, including means for transmitting an initial ranging signal and waiting to receive a first ranging signal transmitted by the responding UE according to a first ranging signal resource.

[0284] 69. A non-transient storage medium including program code stored thereon, the program code being operable to configure at least one processor in an initiating user equipment (UE) for ranging between UEs, the program code including instructions for the following operations:

[0285] The responding UE is sent a first ranging pre-request message to initiate a first ranging session. The first ranging pre-request message includes first ranging signal resources, which include the time and frequency for the responding UE to broadcast a first ranging signal during the first ranging session; and

[0286] The responding UE receives a first ranging pre-response message, which indicates a conflict between a first ranging signal resource used for a first ranging signal and a second ranging signal resource used for a second ranging signal for a second initiating UE.

[0287] 70. The non-transient storage medium including program code as described in Clause 69 further includes program code for the following operations:

[0288] Determine the available time for the responding UE to broadcast the first ranging signal; and

[0289] A second ranging pre-request message is transmitted to the responding UE to initiate a first ranging session. The second ranging pre-request message includes a third ranging signal resource, which includes the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session based on the available time.

[0290] 71. A non-transient storage medium including program code, as in Clause 70, wherein the first ranging pre-response message includes an available time for the responding UE to broadcast the first ranging signal.

[0291] 72. A non-transient storage medium including program code, such as any of Clauses 70-71, wherein the available time for the responding UE to broadcast the first ranging signal is based on the time for broadcasting the first ranging signal included in the first ranging signal resource and a predetermined time period.

[0292] 73. A non-transient storage medium including program code, as in Clause 72, wherein the predetermined time period is based on the maximum waiting time of the listen-before-transmit procedure for broadcasting the first ranging signal.

[0293] 74. A non-transient storage medium including program code, as in Clause 72, wherein the predetermined time period is a predetermined conflict threshold time period.

[0294] 75. A non-transient storage medium including program code, such as that described in any of Clauses 70-74, further includes program code for the following operations:

[0295] The responding UE receives a second pre-ranging response message acknowledging receipt of the second pre-ranging request message; and

[0296] Performing a first ranging session with the responding UE includes: receiving a first ranging signal transmitted by the responding UE according to a third ranging signal resource.

[0297] 76. The non-transient storage medium including program code as described in Clause 70 further includes program code for performing a first ranging session with the responding UE, which includes program code for transmitting an initial ranging signal and waiting to receive a first ranging signal transmitted by the responding UE according to a first ranging signal resource.

[0298] Therefore, the subject matter claimed is not intended to be limited to the specific examples disclosed, but may also include all aspects falling within the scope of the appended claims and their equivalents.

Claims

1. A method for ranging between UEs, performed by a responding user equipment (UE), the method comprising: The first initiating UE receives a first ranging pre-request message to initiate a first ranging session. The first ranging pre-request message includes a first ranging signal resource. The first ranging signal resource includes the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session. The second initiating UE receives a second ranging pre-request message to initiate a second ranging session. The second ranging pre-request message includes second ranging signal resources. The second ranging signal resources include the time and frequency for the responding UE to broadcast the second ranging signal in the second ranging session. The conflict between the first ranging signal and the second ranging signal is determined based on the first ranging signal resource and the second ranging signal resource; Send a first pre-ranging response message to the first initiating UE acknowledging receipt of the first pre-ranging request message; and Send a second pre-ranging response message to the second initiating UE, indicating the conflict with the second ranging signal resource used for the second ranging signal.

2. The method of claim 1, wherein determining the conflict between the first ranging signal and the second ranging signal comprises: The time for broadcasting the second ranging signal is determined to be within a predetermined time period for broadcasting the first ranging signal.

3. The method of claim 2, wherein the predetermined time is a predetermined maximum waiting time for the listen-before-transmit procedure for broadcasting the second ranging signal.

4. The method of claim 2, wherein the predetermined time is a predetermined conflict threshold time.

5. The method of claim 2, wherein determining the conflict between the first ranging signal and the second ranging signal comprises: It is determined that the frequency used to broadcast the second ranging signal is the same as the frequency used to broadcast the first ranging signal.

6. The method of claim 1, further comprising: Determine an available time for broadcasting the second ranging signal, wherein the second ranging pre-response message includes the available time for broadcasting the second ranging signal.

7. The method of claim 6, wherein the available time for broadcasting the second ranging signal is based on the time for broadcasting the first ranging signal included in the first ranging signal resource.

8. The method of claim 7, wherein the available time for broadcasting the second ranging signal is further based on a predetermined maximum waiting time of the listen-before-broadcast procedure for broadcasting the first ranging signal.

9. The method of claim 7, wherein the available time for broadcasting the second ranging signal is further based on a predetermined collision threshold time.

10. The method of claim 1, further comprising: The second initiating UE receives a third ranging pre-request message to initiate the second ranging session. The third ranging pre-request message includes third ranging signal resources, which include the time and frequency for the responding UE to broadcast the second ranging signal in the second ranging session.

11. The method of claim 10, further comprising: The first ranging session is performed with the first initiating UE, which includes broadcasting the first ranging signal according to the first ranging signal resource; as well as The second ranging session is performed with the second initiating UE, which includes broadcasting the second ranging signal according to the third ranging signal resource.

12. A responding UE configured to perform ranging between user equipment (UEs), the responding UE comprising: A wireless transceiver configured to communicate wirelessly with an entity in a wireless network; At least one memory; as well as At least one processor, coupled to the wireless transceiver and the at least one memory, wherein the at least one processor is configured to: The first initiating UE receives a first ranging pre-request message to initiate a first ranging session. The first ranging pre-request message includes a first ranging signal resource. The first ranging signal resource includes the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session. The second initiating UE receives a second ranging pre-request message to initiate a second ranging session. The second ranging pre-request message includes second ranging signal resources. The second ranging signal resources include the time and frequency for the responding UE to broadcast the second ranging signal in the second ranging session. The conflict between the first ranging signal and the second ranging signal is determined based on the first ranging signal resource and the second ranging signal resource; Send a first pre-ranging response message to the first initiating UE acknowledging receipt of the first pre-ranging request message; and Send a second pre-ranging response message to the second initiating UE, indicating the conflict with the second ranging signal resource used for the second ranging signal.

13. The responder UE of claim 12, wherein the at least one processor is configured to determine the conflict between the first ranging signal and the second ranging signal by performing the following operation: determining that the time for broadcasting the second ranging signal is within a predetermined amount of time for broadcasting the first ranging signal.

14. The responder UE as claimed in claim 13, wherein the predetermined time amount is a predetermined maximum waiting time for the listen-before-transmit procedure for broadcasting the second ranging signal.

15. The responder UE as described in claim 13, wherein the predetermined time amount is a predetermined conflict threshold time.

16. The responder UE of claim 13, wherein the at least one processor is configured to determine the conflict between the first ranging signal and the second ranging signal by performing the following operation: determining that the frequency used to broadcast the second ranging signal is the same as the frequency used to broadcast the first ranging signal.

17. The responder UE of claim 12, wherein the at least one processor is further configured to: determine an available time for broadcasting the second ranging signal, wherein the second pre-ranging response message includes the available time for broadcasting the second ranging signal.

18. The responder UE of claim 17, wherein the available time for broadcasting the second ranging signal is based on the time for broadcasting the first ranging signal included in the first ranging signal resource.

19. The responding UE of claim 18, wherein the available time for broadcasting the second ranging signal is further based on a predetermined maximum waiting time of the listen-before-broadcast procedure for broadcasting the first ranging signal.

20. The responding UE of claim 18, wherein the available time for broadcasting the second ranging signal is further based on a predetermined conflict threshold time.

21. The responding UE of claim 12, wherein the at least one processor is further configured to: receive from the second initiating UE a third ranging pre-request message for initiating the second ranging session, the third ranging pre-request message including third ranging signal resources, the third ranging signal resources including a time and frequency for the responding UE to broadcast the second ranging signal in the second ranging session.

22. The responder UE of claim 21, wherein the at least one processor is further configured to: The first ranging session is executed with the first initiating UE, which is configured to perform the following operations: broadcasting the first ranging signal according to the first ranging signal resource; and The second ranging session is performed with the second initiating UE by being configured to broadcast the second ranging signal according to the third ranging signal resource.

23. A responding UE configured to perform ranging between user equipment (UEs), the responding UE comprising: A means for receiving a first ranging pre-request message from a first initiating UE to initiate a first ranging session, the first ranging pre-request message including a first ranging signal resource, the first ranging signal resource including a time and frequency for the responding UE to broadcast a first ranging signal in the first ranging session; A means for receiving a second ranging pre-request message from a second initiating UE to initiate a second ranging session, the second ranging pre-request message including a second ranging signal resource, the second ranging signal resource including a time and frequency for the responding UE to broadcast a second ranging signal in the second ranging session; A means for determining a conflict between the first ranging signal and the second ranging signal based on the first ranging signal resource and the second ranging signal resource; A means for sending a first pre-ranging response message to the first initiating UE acknowledging receipt of the first pre-ranging request message; as well as A means for sending a second pre-ranging response message to the second initiating UE indicating a conflict with the second ranging signal resource used for the second ranging signal.

24. The responder UE of claim 23, wherein the means for determining the conflict between the first ranging signal and the second ranging signal comprises: A means for determining that the time for broadcasting the second ranging signal is within a predetermined time amount of the time for broadcasting the first ranging signal, wherein the predetermined time amount is a predetermined maximum waiting time or a predetermined conflict threshold time of the listen-before-transmit procedure for broadcasting the second ranging signal.

25. The responder UE of claim 24, wherein the means for determining the conflict between the first ranging signal and the second ranging signal comprises: A means for determining that the frequency used to broadcast the second ranging signal is the same as the frequency used to broadcast the first ranging signal.

26. The responder UE as described in claim 23, further comprising: A means for determining an available time for broadcasting the second ranging signal, wherein the second ranging pre-response message includes the available time for broadcasting the second ranging signal.

27. The responding UE of claim 26, wherein the available time for broadcasting the second ranging signal is based on the time for broadcasting the first ranging signal included in the first ranging signal resource.

28. The responding UE of claim 27, wherein the available time for broadcasting the second ranging signal is further based on a predetermined maximum waiting time of the listen-before-broadcast procedure for broadcasting the first ranging signal.

29. The responding UE of claim 27, wherein the available time for broadcasting the second ranging signal is further based on a predetermined conflict threshold time.

30. The responder UE as described in claim 23, further comprising: A means for receiving a third ranging pre-request message from the second initiating UE to initiate the second ranging session, the third ranging pre-request message including a third ranging signal resource, the third ranging signal resource including a time and frequency for the responding UE to broadcast the second ranging signal in the second ranging session.

31. The responder UE as described in claim 30, further comprising: A means for performing the first ranging session with the first initiating UE, wherein performing the first ranging session includes broadcasting the first ranging signal according to the first ranging signal resource; as well as A means for performing the second ranging session with the second initiating UE, wherein performing the second ranging session includes broadcasting the second ranging signal according to the third ranging signal resource.

32. A method for ranging between UEs performed by an initiating user equipment (UE), the method comprising: The responding UE is sent a first ranging pre-request message to initiate a first ranging session. The first ranging pre-request message includes first ranging signal resources, which include a time and frequency for the responding UE to broadcast a first ranging signal during the first ranging session. The responding UE receives a first ranging pre-response message, which indicates a conflict between the first ranging signal resource used for the first ranging signal and the second ranging signal resource used for the second ranging signal for the second initiating UE.

33. The method of claim 32, further comprising: Determine the available time for the responding UE to broadcast the first ranging signal; as well as A second ranging pre-request message is transmitted to the responding UE to initiate the first ranging session. The second ranging pre-request message includes a third ranging signal resource, which includes the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session based on the available time.

34. The method of claim 33, wherein the first ranging pre-response message includes the available time for the responding UE to broadcast the first ranging signal.

35. The method of claim 33, wherein the available time for the responding UE to broadcast the first ranging signal is based on the time included in the first ranging signal resource for broadcasting the first ranging signal and a predetermined time period.

36. The method of claim 35, wherein the predetermined time period is based on the maximum waiting time of the listen-before-transmit procedure for broadcasting the first ranging signal.

37. The method of claim 35, wherein the predetermined time period is a predetermined conflict threshold time period.

38. The method of claim 33, further comprising: The responding UE receives a second pre-ranging response message acknowledging receipt of the second pre-ranging request message; as well as Performing the first ranging session with the responding UE includes: receiving the first ranging signal transmitted by the responding UE according to the third ranging signal resource.

39. The method of claim 32, further comprising: Performing the first ranging session with the responding UE includes: transmitting an initial ranging signal and waiting to receive the first ranging signal transmitted by the responding UE according to the first ranging signal resource.

40. An initiating UE configured to perform ranging between user equipment (UEs), the initiating UE comprising: A wireless transceiver configured to communicate wirelessly with an entity in a wireless network; At least one memory; as well as At least one processor, coupled to the wireless transceiver and the at least one memory, wherein the at least one processor is configured to: The responding UE is sent a first ranging pre-request message to initiate a first ranging session. The first ranging pre-request message includes first ranging signal resources, which include a time and frequency for the responding UE to broadcast a first ranging signal during the first ranging session. The responding UE receives a first ranging pre-response message, which indicates a conflict between the first ranging signal resource used for the first ranging signal and the second ranging signal resource used for the second ranging signal for the second initiating UE.

41. The initiating UE of claim 40, wherein the at least one processor is further configured to: Determine the available time for the responding UE to broadcast the first ranging signal; and A second ranging pre-request message is transmitted to the responding UE to initiate the first ranging session. The second ranging pre-request message includes a third ranging signal resource, which includes the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session based on the available time.

42. The initiating UE of claim 41, wherein the first ranging pre-response message includes the available time for the responding UE to broadcast the first ranging signal.

43. The initiating UE as claimed in claim 41, wherein the available time for the responding UE to broadcast the first ranging signal is based on the time for broadcasting the first ranging signal included in the first ranging signal resource and a predetermined time period.

44. The initiating UE as claimed in claim 43, wherein the predetermined time period is based on the maximum waiting time of the listen-before-transmit procedure for broadcasting the first ranging signal.

45. The initiating UE as described in claim 43, wherein the predetermined time period is a predetermined conflict threshold time period.

46. ​​The initiating UE as claimed in claim 41, wherein the at least one processor is further configured to: Receives a second pre-ranging response message from the responding UE acknowledging receipt of the second pre-ranging request message; and The first ranging session is performed with the responding UE, which includes: Receive the first ranging signal transmitted by the responding UE according to the third ranging signal resource.

47. The initiating UE of claim 40, wherein the at least one processor is configured to perform the first ranging session with the responding UE by transmitting an initial ranging signal and waiting to receive the first ranging signal transmitted by the responding UE according to the first ranging signal resource.

48. An initiating UE configured to perform ranging between user equipment (UEs), the initiating UE comprising: A means for transmitting a first ranging pre-request message to a responding UE to initiate a first ranging session, the first ranging pre-request message including first ranging signal resources, the first ranging signal resources including a time and frequency for the responding UE to broadcast a first ranging signal in the first ranging session; and A means for receiving a first ranging pre-response message from the responding UE, the first ranging pre-response message indicating a conflict between a first ranging signal resource for the first ranging signal and a second ranging signal resource for a second ranging signal for the second initiating UE.

49. The initiating UE as described in claim 48, further comprising: A means for determining the available time for the responding UE to broadcast the first ranging signal; as well as A means for transmitting a second ranging pre-request message to the responding UE to initiate the first ranging session, the second ranging pre-request message including a third ranging signal resource, the third ranging signal resource including, based on the available time, the time and frequency for the responding UE to broadcast the first ranging signal in the first ranging session.

50. The initiating UE of claim 49, wherein the first ranging pre-response message includes the available time for the responding UE to broadcast the first ranging signal.

51. The initiating UE as claimed in claim 49, wherein the available time for the responding UE to broadcast the first ranging signal is based on the time included in the first ranging signal resource for broadcasting the first ranging signal and a predetermined time period, the predetermined time period being based on the maximum waiting time of the listen-before-transmit procedure for broadcasting the first ranging signal or a predetermined conflict threshold time period.

52. The initiating UE as described in claim 49, further comprising: A means for receiving a second pre-ranging response message from the responding UE confirming receipt of the second pre-ranging request message; as well as A means for performing the first ranging session with a responding UE, the performing the first ranging session including receiving the first ranging signal transmitted by the responding UE according to the third ranging signal resource.

53. The initiating UE as described in claim 48, further comprising: A means for performing the first ranging session with a responding UE, comprising means for transmitting an initial ranging signal and waiting to receive the first ranging signal transmitted by the responding UE according to the first ranging signal resource.

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