Vehicle and pedestrian positioning using ranging signals

Abstract

A target UE, which may be a vehicle- or pedestrian-carried user equipment (UE), may receive continuously broadcast ranging signals from a set of ranging source entities (SEs), which may be roadside units or other vehicles. The target UE further receives location information broadcast separately by each SE. The location information may include, for example, the location of the SE, the transmission time of the ranging signal transmitted by the SE, and / or a sequence identifier of the SE. The target UE may determine the distance to the SE using the arrival time measurement of the ranging signal and the transmission time of the ranging signal or the sequence identifier received in the location information. The location of the target UE may be determined using the determined distance to the SE and the location of the SE received in the location information.

Description

[Technical field]

[0001] Claiming priority This patent application claims priority to U.S. Non-provisional Application No. 16 / 698,295, entitled “POSITIONING OF VEHICLES AND PEDESTRIANS LEVERAGING RANGING SIGNAL,” filed November 27, 2019, which is assigned to the assignee of the present application and is expressly incorporated herein by reference.

[0002] The subject matter disclosed herein relates to wireless communication systems, and more particularly, to methods and apparatus for location determination of user equipment within a wireless communication system. [Background technology]

[0003] Obtaining precise location information for user equipment, such as cellular telephones or other wireless communication devices, is becoming commonplace in the communications industry. For example, obtaining highly accurate locations of vehicles or pedestrians is essential for autonomous vehicle driving and pedestrian safety applications.

[0004] A common means for determining the location of a device is to use a satellite positioning system (SPS), such as the well-known Global Positioning Satellite (GPS) system or Global Navigation Satellite System (GNSS), which uses several satellites in orbit around the Earth. However, in some scenarios, location determination signals from an SPS may be unavailable, for example in areas with poor satellite signal reception, such as tunnels or parking complexes. Furthermore, position information generated using an SPS is prone to inaccuracies. For example, off-the-shelf GPS positioning devices have an accuracy of a few meters, which is not optimal for ensuring safe autonomous driving and navigation.

[0005] To increase the accuracy of location determination, it may be desirable to use signals from one or more terrestrial sources. For example, signals to determine distance to a fixed roadside unit or from a moving vehicle with a known location may be used by a target vehicle or pedestrian for positioning. Round trip time (RTT) is a technique commonly used to determine the location of, for example, a target vehicle or pedestrian. RTT is a two-way messaging technique in which the time (minus processing delays) between sending a signal from a first device and receiving an acknowledgment from a second device corresponds to the distance or range between the two devices. While RTT is accurate, it would be desirable to reduce the power consumption required by two-way messaging. Summary of the Invention [Means for solving the problem]

[0006] A target UE, which may be a vehicle or pedestrian carried user equipment (UE), may receive continuously broadcasted ranging signals from a set of ranging source entities (SEs), which may be roadside units or other vehicles. The ranging signals may be wideband signals having adjacent or non-adjacent frequency channels. The target UE further receives location information broadcasted by each SE separately. The location information may include, for example, a position of the SE, a transmission time of the ranging signal transmitted by the SE and / or a sequence identifier of the SE. The target UE may determine a distance to the SE using a time-of-arrival measurement of the ranging signal and the transmission time of the ranging signal or the sequence identifier received in the location information. The location of the target UE may be determined using the determined distance to the SE and the position of the SE received in the location information.

[0007] In one implementation, a method for performing location determination by a user equipment (UE) includes receiving ranging signals broadcast by each entity among a plurality of entities in a wireless network, receiving a message having location information broadcast from each entity among the plurality of entities, determining a distance to each entity using the ranging signals received from each entity and the location information received from each entity, and determining a position of the user equipment based on the distance to each entity and the known location of each entity.

[0008] In one implementation, a user equipment (UE) configured to support location determination includes a wireless transceiver configured to receive broadcast signals from entities in a wireless network, at least one memory, and at least one processor coupled to the wireless transceiver and the at least one memory, where the at least one processor is configured to: receive ranging signals broadcast by each entity among a plurality of entities in the wireless network; receive messages having location information broadcast from each entity among the plurality of entities; determine a distance to each entity using the ranging signals received from each entity and the location information received from each entity; and determine a position of the user equipment based on the distance to each entity and the known locations of each entity.

[0009] In one implementation, a user equipment (UE) configured to support location determination includes means for receiving ranging signals broadcast by each entity among a plurality of entities in a wireless network, means for receiving a message having location information broadcast from each entity among the plurality of entities, means for determining a distance to each entity using the ranging signals received from each entity and the location information received from each entity, and means for determining a position of the user equipment based on the distance to each entity and the known location of each entity.

[0010] In one implementation, a non-transitory computer-readable medium having program code stored thereon, operable to configure at least one processor in a user equipment (UE) to perform location determination, includes program code for receiving ranging signals broadcast by each entity among a plurality of entities in a wireless network, program code for receiving a message having location information broadcast from each entity among the plurality of entities, program code for determining a distance to each entity using the ranging signals received from each entity and the location information received from each entity, and program code for determining a position of the user equipment based on the distance to each entity and the known location of each entity.

[0011] In one implementation, a method for supporting location determination of a user equipment (UE) performed by an entity in a wireless network includes the steps of determining an available portion of a wireless spectrum by the entity, the entity being one of a plurality of ranging sources for the UE; generating a ranging signal on the available portion of the wireless spectrum; broadcasting the ranging signal to be received by the UE; and broadcasting a message having location information regarding the ranging signal.

[0012] In one implementation, an entity in a wireless network capable of supporting location determination of a user equipment (UE) includes a wireless transceiver configured to broadcast a signal to a UE in the wireless network, at least one memory, and at least one processor coupled to the wireless transceiver and the at least one memory, where the at least one processor is configured to: determine an available portion of a wireless spectrum by the entity, where the entity is one of a plurality of ranging sources for the UE; generate a ranging signal on the available portion of the wireless spectrum; broadcast the ranging signal to be received by the UE; and broadcast a message having location information related to the ranging signal.

[0013] In one implementation, an entity in a wireless network capable of supporting location determination of a user equipment (UE) includes means for determining an available portion of a wireless spectrum by the entity, where the entity is one of a plurality of ranging sources for the UE, means for generating a ranging signal on the available portion of the wireless spectrum, means for broadcasting the ranging signal to be received by the UE, and means for broadcasting a message having location information regarding the ranging signal.

[0014] In one implementation, a non-transitory computer-readable medium having program code stored thereon operable to configure at least one processor among an entity in a wireless network user equipment (UE) to support location determination of the user equipment (UE), the program code includes: program code for determining an available portion of a wireless spectrum by the entity, the entity being one of a plurality of ranging sources for the UE; program code for generating a ranging signal on the available portion of the wireless spectrum; program code for broadcasting the ranging signal to be received by the UE; and program code for broadcasting a message having location information related to the ranging signal.

[0015] Non-limiting and non-exhaustive aspects are described with reference to the following figures, in which like reference numerals refer to like parts throughout the various figures unless otherwise specified. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 illustrates a wireless communication system in which a target user equipment (UE), shown as a vehicle, is in wireless communication with other entities within the wireless communication system. [Diagram 2] FIG. 1 illustrates a simplified environment and an example technique for determining a location of a target UE using one-sided ranging signals from multiple entities in a wireless communication system. [Diagram 3] FIG. 2 illustrates an example of a call flow for a location determination session with a target UE and a set of entities in a wireless communication system. [Figure 4] 4 is a flow chart illustrating a method of performing location determination by user equipment. [Diagram 5] 1 is a flowchart illustrating a method of supporting location determination of user equipment by entities in a wireless network. [Figure 6] FIG. 1 illustrates an example of a hardware implementation of a user equipment capable of performing location determination using continuously broadcasted ranging signals. [Figure 7] FIG. 2 illustrates an example of a hardware implementation of a ranging source entity capable of supporting location determination of a user equipment using a continuously broadcasted ranging signal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Positioning of a target vehicle or pedestrian may use one-sided ranging signals from a transmitter with a known location, such as a fixed roadside unit (RU) or a moving vehicle with a known location. The use of one-sided ranging signals reduces power consumption compared to traditional ranging techniques, such as round trip time (RTT) techniques, since no acknowledgement signal is required to be sent or received.

[0018] To improve ranging performance and reduce channel access overhead, participating entities may be clustered for consecutive transmission of their ranging signals. The ranging signal may be a wideband waveform with multiple adjacent or non-adjacent channels. After broadcasting the ranging signal, each entity may further broadcast a message including location information such as the entity's position, sequence ID, and the time the ranging signal was transmitted so that the target device may determine the distance to the entity.

[0019] 1 illustrates a wireless communication system 100 in which a target user equipment (UE) 102, depicted as a vehicle, is in wireless communication with other entities 104 and 106 within the wireless communication system 100. As illustrated, the target UE 102 may communicate directly with an entity 104, depicted as a roadside unit (RSU) 104, using a vehicle-to-infrastructure (V2I) communication link 105 and with an entity 106, depicted as another vehicle 106, using a vehicle-to-vehicle (V2V) communication link 107. The roadside unit (RSU) is a fixed infrastructure entity that may support V2X applications and can exchange messages with other entities that support V2X applications. An RSU may be a logical entity that may combine V2X application logic with functions of a base station in a Radio Access Network (RAN), such as an evolved Node B (eNB) or Next Generation evolved Node B (ng-eNB) in LTE wireless access and / or an evolved LTE (eLTE) wireless access (referred to as an eNB-type RSU) or NR Node B (gNB) in fifth-generation (5G) wireless access, or a user equipment (UE) (referred to as an UE-type RSU). The target UE 102 may communicate with additional entities, such as additional RSUs, vehicles, or pedestrians (not shown), for example in a vehicle-to-pedestrian (V2P) communication link.

[0020] The wireless communications may be, for example, via the Proximity-based Services (ProSe) Direct Communication (PC5) reference point defined in 3rd Generation Partnership Project (3GPP®) Technical Specification (TS) 23.303, using wireless communications on the 5.9 GHz ITS band under IEEE 1609, Wireless Access in Vehicular Environments (WAVE), Intelligent Transport Systems (ITS), and IEEE 802.11p, or using other wireless connections directly between the entities.

[0021] For positioning of the target UE 102, the ranging source equipment (SE), e.g., entities 104 and 106, may transmit one-sided ranging signals, i.e., no acknowledgement message is transmitted in response to the ranging signal. The ranging signal may be transmitted, for example, on an unlicensed spectrum. Conventionally, transmission on an unlicensed spectrum follows a Listen-Before-Talk (LBT) procedure prior to transmission. For example, typically, prior to transmitting on a medium, a wireless transmitter is required to first sense the medium and transmit only if the medium is sensed to be idle, which may be referred to as Clear Channel Assessment (CCA). If all the SEs, e.g., RSU 104 and vehicle 106, transmit their ranging signals independently, each would be required to separately perform an LBT procedure prior to transmission, resulting in inefficient channel access and possibly preventing timely delivery of the ranging signal.

[0022] Due to the mobility of the target UE 102, which may be, for example, a vehicle or a pedestrian, as well as the possible mobility of the SE, for example, the vehicle 106, multiple ranging signals need to reach the target UE 102 within a fairly small time window, i.e., with an acceptably small amount of movement of the target UE 102 (or SE) between reception of the ranging signals, otherwise ranging performance may degrade. Furthermore, the overhead of the LBT procedure scales with the number of entities. Therefore, to improve ranging performance and reduce channel access overhead, participating entities (i.e., SEs) are clustered for consecutive transmission of their ranging signals.

[0023] In addition, the unlicensed spectrum may be made up of component channels, e.g., an 80 MHz unlicensed spectrum has components of 4×20 MHz channels or 2×40 MHz channels. Other wireless nodes may be transmitting on any of the component channels at any given time. For example, the entire 80 MHz, or one or more 20 MHz channels, or one or more 40 MHz channels may be occupied. To avoid interfering with transmissions from other wireless nodes, an SE may use a subset of the free 20 MHz component channels for transmission, e.g., as determined by a single SE, e.g., the first or head SE in a cluster of SEs.

[0024] Although the target UE 102 monitors the time of arrival (TOA) of each one-sided ranging signal, the transmission time of the ranging signal is unknown to the target UE 102. Thus, in addition to broadcasting the ranging signal, the SE broadcasts location information that can be used by the target UE 102 to determine the distance to each SE. For example, the SE may broadcast the exact time the ranging signal was transmitted, which the target UE 102 may use along with the TOA of the ranging signal to determine a time of flight that can be converted to a distance to the SE. Thus, the target UE 102 may constantly monitor the channel for ranging signals. Close in time to, e.g., before or after, the broadcast of a ranging signal from the SE, each SE sends location information for its ranging signal. The location information may include, for example, the transmission time of the ranging signal, the location of the SE, the bandwidth used in the ranging signal, or other configuration information, etc. Using the location information for the ranging signal from the SE, e.g., the transmission time of the ranging signal, and using the arrival time of the ranging signal measured by the target UE 102, the target UE 102 may back-calculate the time of flight of the ranging signal and thus the distance to each SE.

[0025] In some implementations, the location information broadcast by one or more SEs may include a sequence identifier of the SE in addition to or instead of the transmission time of the ranging signal, e.g., if the location information is transmitted by one or more SEs before broadcasting a ranging signal. The sequence identifier indicates the position of the SE in the sequence of broadcasts of the ranging signal from a cluster of SEs. i Sequence identifier seq# i If the transmission time is not included in the location information, e.g., i For example, the target UE 102 may include, in the location information from, for example, the first SE or the head SE, a transmission time T0 of the first ranging signal, as well as a time T between each ranging signal transmission.trans Then, the transmission time of any SE may be, for example, T0+(seq# i *T trans ) can be determined as

[0026] The location information broadcast by the SE may further include, for example, the location of the SE. In addition, in some implementations, the SE may further include, in the location information or in a different message, the TOA of one or more ranging signals from other SEs measured by the SE. The location information may be transmitted by the SE in a licensed spectrum, for example, in an Intelligent Transport System (ITS) spectrum.

[0027] FIG. 2 illustrates a simplified environment and an example technique for determining a location of a target UE 102 using one-sided ranging signals from multiple entities in a wireless communication system 200. The target UE 102 may wirelessly communicate with SEs, including a first RSU 104-1, a second RSU 104-2, and another vehicle 106, having known locations, using radio frequency (RF) signals and a standardized protocol for modulation of the RF signals and exchange of information packets. By extracting different types of information from the exchanged signals and utilizing the layout of the network (i.e., network geometry), the target UE 102 may determine its location in a predefined reference coordinate system. As shown in FIG. 2, the target UE 102 may specify its location (x, y) using a two-dimensional coordinate system, although aspects disclosed herein are not so limited and may be applicable to determining a location using a three-dimensional coordinate system if additional dimensions are desired. Additionally, although three entities are illustrated in FIG. 2, aspects may utilize additional entities. For example, three SEs may be used to determine a position (x, y) in a two-dimensional coordinate system, while four or more SEs may be used to determine a position (x, y, z) in a three-dimensional coordinate system. However, in some implementations, fewer than three SEs may be used to determine an accurate location of the target UE, e.g., in conjunction with SPS positioning or another positioning system. For example, if SPS positioning results in a relatively inaccurate location of the target UE, ranging signals from two SEs or a single SE may be used to improve the accuracy of the location of the target UE.

[0028] To determine its position (x, y), the target UE 102 needs to determine the range or distance (dk, where k=1, 2, 3) to each of the entities 104-1, 104-2, and 106, as well as the network geometry. The network geometry may include the position ((xk, yk), where k=1, 2, 3) of each of the entities 104-1, 104-2, and 106 in a reference coordinate system.

[0029] As shown, each SE 104-1, 104-2, and 106 broadcasts RF signals 201, 202, and 203, respectively, that are received by the target UE 102. The RF signals 201, 202, and 203 include one-sided ranging signals from each entity 104-1, 104-2, and 106. The ranging signals may be, for example, Positioning Reference Signals (PRS) or Sounding Reference Signals (SRS) used in Long Term Evolution (LTE) defined in 3GPP. As discussed above, the target UE 102 may measure the TOA of the ranging signal. Each SE 104-1, 104-2, and 106 further broadcasts location information, which the target UE may use to determine the time of flight of the ranging signal. For example, the location information may include a transmission time and / or a sequence identifier of the SE from which the transmission time may be determined.

[0030] Using the time of flight of the ranging signal, the distance between the target UE 102 and the SE may be determined, for example, based on the speed of light. In this manner, the range or distance (dk, where k=1, 2, 3) to each of the entities 104-1, 104-2, and 106 may be determined, as shown in FIG. 2. With each distance determined and the network geometry known, e.g., the location ((xk, yk), where k=1, 2, 3) of each of the entities 104-1, 104-2, and 106, the target UE 102 may then determine its location (x, y) by using various known geometric techniques, such as, for example, trilateration. From FIG. 2, it can be seen that the location of the target UE 102 is ideally located at the common intersection of all of the circles 202, 204, and 206, which are drawn using dotted lines. Each circle is defined by a radius dk and a center ((xk, yk), where k=1, 2, 3). In practice, the intersections of these circles may not be located at a single point due to noise and other errors in the networking system. The network geometry, e.g., the position ((xk, yk), where k=1, 2, 3) of each of the entities 104-1, 104-2, and 106, may also be provided in the broadcasted location information. Using the positions of the entities 104-1, 104-2, and 106 and the intersections of the circles 202, 204, and 206 around the SEs 104-1, 104-2, and 106, the location of the target UE 102 may be determined.

[0031] In some implementations, the one-sided ranging signals may be used together with other types of positioning procedures. For example, the one-sided ranging signals and positioning may be used together with SPS positioning. For example, for a target UE using SPS, if a relatively inaccurate position is acquired, for example with an error of several meters, the one-sided ranging signals and positioning may be used to improve the acquired position, for example, reducing the error to tens of centimeters.

[0032] A cluster or set of ranging SEs is established to generate ranging signals to be used by the target UE 102. For example, referring to FIG. 2, a set of SEs may be established as roadside units 104-1, 104-2 and a vehicle 106. In some implementations, the set of SEs may be capable of transmitting ranging waveforms in the unlicensed spectrum and transmitting location information in the licensed spectrum, for example. The set of SEs may be physically close to each other, for example. The set of SEs may be a set of one, i.e., the set may include a single roadside unit 104 or a single vehicle 106.

[0033] The set of SEs may include a head SE, e.g., RSU 104-1 in FIG. 2, which may be chosen arbitrarily or according to a predefined criterion. For example, a particular roadside unit may be given priority as a head SE. The head SE 104-1 may be enabled to sense the received signal power of a channel (frequency resource) in the spectrum, on which the ranging signal will be transmitted, which may be unlicensed. The head SE 104-1 detects the energy levels of different channels in the spectrum. The head SE 104-1 generates a wideband ranging signal, which may be of short duration, based on the detected energy levels of the different channels. The ranging waveform may consist of one or more unoccupied channels. If one or more channels are considered “occupied”, the ranging waveform is generated by puncturing the occupied channels, i.e., the ranging waveform is generated without the occupied channels, such that the ranging waveform uses only “unoccupied” or “free” channels. Thus, the ranging waveform may include multiple channels, which may be adjacent or non-adjacent. The generated ranging signals may be transmitted on demand or multiple times, e.g., periodically, by a set of SEs, where the ranging signals may have the same configuration of channels or different configurations of channels.

[0034] The generated ranging signal may include a preamble that includes an indication that the channel will be used in ranging signals and that the channel will be occupied for a period of time, e.g., the time it would take each SE in the set of SEs to transmit their individual ranging signals consecutively. For example, if each ranging signal is 2 ms long and there are 5 SEs in the set of SEs that will transmit their ranging signals consecutively, the preamble may indicate that the channel will be occupied for 10 ms or slightly longer to accommodate some additional configuration time for the SEs to check for ranging signals transmitted in a cluster.

[0035] Each non-head SE in the set of SEs, e.g., RSU 104-2 and vehicle 106, may be arbitrarily assigned a sequence identifier that indicates the positioning of the SE in the sequence of ranging signal transmissions. For example, in one implementation, the sequence of SEs may be based in part on a predefined identity of each SE, which may be assigned (or self-assigned) prior to the procedure. For example, the predefined identity may be determined as a Layer 2 Identifier (L2 ID) mod #SE. As an example, in FIG. 2, RSU 104-2 may be assigned a second location, e.g., a location immediately after head SE 104-1, and vehicle 106 may be assigned a third location. Each SE 104-2 and vehicle 106 may determine the channel to be included in the ranging waveform from the broadcasted ranging signal received from head SE 104-1 (or from any preceding SE). The SE 104-2 and the vehicle 106 may determine the available channels, i.e., the portion of the wireless spectrum to be used for the ranging signal, for example, by inspecting the ranging waveform from the preceding SE or by inspecting the preamble of the ranging signal from the preceding SE. Each SE 104-2 and 106 independently generates the ranging signal using the determined available channel. The ranging signal may be similar to a PRS or SRS. In one implementation, the ranging signal may also depend in part on a predefined identity. For example, the ranging signal may be a base sequence with a cyclic shift determined as L2 ID mod N, where N is a code division multiplexing (CDM) factor (e.g., N=3 cyclic shifts per base sequence). Each SE 104-2 and 106 may further generate a preamble indicating the channel to be used in the ranging signal and, in some implementations, the remaining time the channel will be occupied.

[0036] Each SE in the set of SEs broadcasts its own ranging signal in sequence based on the sequence identifier of the SE. The ranging signals may be broadcast continuously, for example, at 160 MHz or other frequencies. The ranging signals may be broadcast such that there is no time overlap of the ranging signals. The head SE 104-1 broadcasts its ranging signal, which may include a preamble. After detecting the first ranging signal from the head SE 104-1, the remaining SEs 104-2, 106 broadcast their own ranging signals continuously, for example, SE 104-2 broadcasts its ranging signal immediately after receiving the ranging signal from the head SE 104-1, and SE 106 broadcasts its ranging signal at a time ((Seq#)*T Trans ), where Seq# is the sequence number of the SE, and T Trans is the length of time for transmitting each ranging signal. In some implementations, each remaining SE 104-2, 106 may broadcast its own ranging signal immediately after receiving a ranging signal from its immediately preceding SE, e.g., SE 104-2 broadcasts its ranging signal immediately after receiving a ranging signal from head SE 104-1, and SE 106 broadcasts its ranging signal immediately after receiving a ranging signal from SE 104-2.

[0037] Each SE in the set of SEs is further configured to broadcast location information to be used by the target UE 102, including information about the ranging signal and information about positioning, e.g., the location of the SE. The location information may include, for example, the location of the SE, a sequence identifier of the SE, and / or the exact time the ranging signal was transmitted by the SE. The location information broadcast by each SE (or another message broadcast by one or more SEs) may include the TOAs of the ranging signals that the SE detected from other SEs. The location information broadcast from each SE may be broadcast within a certain time window, for example, in the case of vehicle-to-vehicle (V2V) messages, for example, in a radio resource control (RRC) or proximity-based services (ProSe) direct communication (PC5) signaling protocol stack (PC5-S) in a licensed spectrum, e.g., an intelligent transport system (ITS) spectrum. For example, the location information may be broadcast within 10-20 ms to minimize the size of the buffer required for the target UE 102. The location information may be broadcast in a spectrum different from the spectrum used for the ranging signal, thereby avoiding interference between the ranging signal and the location information.

[0038] The target UE 102 receives ranging signals broadcast continuously from each of the SEs 104-1, 104-2, and 106 in the set of SEs. The target UE 102 is configured to receive location information broadcast separately from each SE 104-1, 104-2, and 106, which may be broadcast by each SE after (or before) the SE transmits its ranging signal. The target UE 102 may use the received location information for its corresponding SE to analyze the ranging signal received from each SE. For example, the target UE 102 may use the transmission time of the ranging signal and the measured reception time of the ranging signal indicated in the received location information to determine the time of flight of the ranging signal. The time of flight may then be converted to a range or distance to the SE, for example, by dividing the time of flight by the speed of light. If the transmission time of the ranging signal is not provided, the target UE 102 may determine the transmission time based on the sequence identifier of the SE along with the known frequency of the ranging signal transmission and the time of the first transmission of the ranging signal, which may be provided by the head SE 104-1. Once the distance to the SE is determined, the target UE 102 may use the position of the SE indicated in the received location information along with the determined distance to determine the position of the target UE 102 using, for example, trilateration. The target UE 102 may more accurately derive its position by combining its relative position utilizing the ranging signal with the determined SPS position.

[0039] In some implementations, the target UE 102 may use the TOA measured by the SEs along with its own TOA measurements to generate a Received Signal Time Difference (RSTD) measurement. For example, the SE 104-2 may provide a TOA measurement of the ranging signal received by the SE 104-2 from the SE 104-1, e.g., in the location information or in a separate message, and similarly, the SE 106 may provide a TOA measurement of the ranging signal received by the SE 106 from the SE 104-1. The target UE 102 may use its own TOA measurement of the ranging signal from the SE 104-1 to generate the RSTD measurement. Thus, the location of the target UE 102 may be determined using the RSTD, e.g., using the Observed Time Difference of Arrival (OTDOA). For a precise location using RSTD, typically four or more SEs may be used.

[0040] 3 illustrates an example of a call flow 300 for a location determination session with a target UE 102 and a set of SEs including head SEs 104-1 and 104-2 and SE 106. It should be appreciated that the target UE 102 may be in communication with one or more SEs prior to initiation of the location determination session.

[0041] As shown, in stage 1, the target UE 102 may send a request for a ranging signal to an SE, for example, the head SE 104-1, which may be a request for a periodic ranging signal or a request for an on-demand ranging signal.

[0042] In stage 2, head SE 104-1 forms a set of SEs including SE 104-2 and SE 106 and provides requests for ranging signals to the SEs in the established set. Head SE 104-1 may be determined to be the head SE in the set, e.g., based on previous contact with target UE 102 (in stage 1) or other mechanisms, e.g., based on the capabilities of SE 104-1. Head SE 104-1 may provide information by which the SEs may identify their sequence number in the set of SEs, e.g., head SE 104-1 may assign a sequence number to each SE or provide information by which each SE may determine its sequence number, e.g., head SE 104-1 may provide the number of SEs in the set, and each SE may determine its sequence number as a Layer 2 Identifier (L2 ID) mod #SE. In some implementations, the set may include only one SE, e.g., head SE 104-1.

[0043] In stage 3, the head SE 104-1 may check the availability of channels on the spectrum to be used for the ranging signal, for example, by detecting the energy levels of different channels in the spectrum to determine if the channel is occupied or free. The head SE 104-1 may generate the ranging signal, for example, using an unoccupied or free channel, and generate a preamble that identifies the used channel and reserves the used channel for the duration of the continuous broadcast of the ranging signal from the SE.

[0044] In stage 4, the head SE 104-1 broadcasts a ranging signal that is received by the target UE 102 and the other SEs in the set of SEs, i.e., SE 104-2 and SE 106. The ranging signal, which may be, for example, a PRS or SRS signal, may be transmitted on an unlicensed spectrum and may be a wideband signal using adjacent or non-adjacent channels. The target UE 102 measures the TOA of the ranging signal from the head SE 104-1.

[0045] In stage 5, the next SE 104-2 in the set of SEs determines available channels in the spectrum, for example, by detecting the channels used or identified in the preamble of the ranging signal received in stage 4. The SE 104-2 generates the ranging signal using the available channels.

[0046] In stage 6, the SE 104-2 broadcasts a ranging signal that is received by the target UE 102 as well as other SEs in the set of SEs, i.e., the SE 106. The ranging signal, which may be, for example, a PRS or SRS signal, may be transmitted on an unlicensed spectrum and may be a wideband signal using adjacent or non-adjacent channels. The target UE 102 measures the TOA of the ranging signal from the SE 104-2.

[0047] In step 7, the next SE 106 in the set of SEs determines an available channel in the spectrum, for example, by detecting the channel used or identified in the preamble of the ranging signal received in step 4 or step 6. The SE 106 generates the ranging signal using the available channel.

[0048] In stage 8, the SE 106 broadcasts a ranging signal that is received by the target UE 102 as well as any other SEs (not shown in FIG. 3) that may be included in the set of SEs. The ranging signal, which may be a PRS or SRS signal, for example, may be transmitted on an unlicensed spectrum and may be a wideband signal using adjacent or non-adjacent channels. The target UE 102 measures the TOA of the ranging signal from the SE 106.

[0049] In stage 9, the head SE 104-1 broadcasts location information of the SE 104-1, which is received by the target UE 102. The location information may be transmitted on a licensed spectrum, such as the ITS spectrum. The location information may include, for example, the location of the SE 104-1, a sequence identifier of the SE 104-1, and the exact time when the ranging signal was transmitted by the SE 104-1.

[0050] In stage 10, the SE 104-2 broadcasts its location information, which is received by the target UE 102. The location information may be transmitted on a licensed spectrum, such as the ITS spectrum. The location information may include, for example, the location of the SE 104-2, a sequence identifier of the SE 104-2, and the exact time the ranging signal was transmitted by the SE 104-2. The location information may further include the TOA of the ranging signal from the head SE 104-1, detected by the SE 104-2 in stage 4.

[0051] In stage 11, the SE 106 broadcasts its location information, which is received by the target UE 102. The location information may be transmitted on a licensed spectrum, such as the ITS spectrum. The location information may include, for example, the location of the SE 106, a sequence identifier of the SE 106, and the exact time the ranging signal was transmitted by the SE 106. The location information may further include the TOAs of the ranging signals from the head SE 104-1 and / or SE 104-2 detected by the SE 106 in stage 4 and / or stage 6.

[0052] In stage 12, the target UE 102 determines the distance to each of the SEs 104-1, 104-2, and 106. The target UE 102 may use the TOAs of the ranging signals measured in stages 4, 6, and 8 and the transmit times received in the location information in stages 9, 10, and 11 to determine, for example, a time of flight of each ranging signal, which may be converted to a range or distance to each of the SEs 104-1, 104-2, and 106. In some implementations, the TOA measurements by the target UE 102 and the transmit times from the SEs may be synchronized, for example, using an RTT method or estimated based on a Kalman filter. The target UE 102 may use the sequence identifier provided in the location information in stages 9, 10, and 11 along with the frequency of the ranging signal transmission from the head SE 104-1 and the transmission time of the ranging signal (which may be included in the preamble of the ranging signal in stage 4 or in the location information received in stage 9) to determine the transmission time of each ranging signal from the SEs 104-2 and 106. In another implementation, the target UE 102 may use the TOA of the ranging signal measured by the SEs provided in the location information in stages 9, 10, and 11 along with the TOA measured by the target UE 102 in stages 4, 6, and 8 to determine the relative ranging signal, e.g., RSTD.

[0053] In stage 13, the target UE 102 may use the distances determined in stage 12 along with the positions of the SEs 104-1, 104-2, and 106 received in the location information in stages 9, 10, and 11 to estimate the position of the target UE 102 using, for example, trilateration or other suitable techniques. In some implementations, the target UE 102 may use the distances determined in stage 12 along with the positions of the SEs 104-1, 104-2, and 106 received in the location information in stages 9, 10, and 11 to estimate the relative position of the target UE 102, which may be combined with the measured SPS positions to derive the precise position of the target UE 102.

[0054] FIG. 4 is a flow chart illustrating a method of performing location determination by a UE, such as the target user equipment (UE) 102 shown in FIG. 1, FIG. 2, and FIG. 3. As shown in block 402, ranging signals broadcast by each entity among the multiple entities in a wireless network are received, for example, as described in steps 4, 6, and 8 shown in FIG. 3. In block 404, messages with location information broadcast from each entity among the multiple entities are received, for example, as described in steps 9, 10, and 11 shown in FIG. 3. The messages with location information may be broadcast at different times than the ranging signals, for example. In block 406, a distance to each entity is determined using the ranging signals received from each entity and the location information received from each entity, for example, as described in step 12 shown in FIG. 3. In block 408, a location of the user equipment is determined based on the distance to each entity and the known location of each entity, for example, as described in step 13 shown in FIG. 3.

[0055] In one implementation, the plurality of entities comprises a cluster of entities that continuously broadcast ranging signals, e.g., as described in steps 4, 6, and 8 shown in Fig. 3. For example, the continuously broadcast ranging signals may be broadcast using the same set of channels without overlap in time. A first ranging signal among the continuously broadcast ranging signals may include an identification of the set of channels in a preamble determined by a first entity in the cluster of entities.

[0056] In one implementation, each ranging signal broadcast by each entity is a wideband waveform with multiple channels, which may be adjacent or the multiple channels may be non-adjacent.

[0057] In one implementation, each entity in the plurality of entities comprises one of a roadside unit or a vehicle.

[0058] In one implementation, each message having location information is received from each entity in an Intelligent Transport System (ITS) spectrum.

[0059] In one implementation, the location information broadcast by the entity may include at least one of a known location of the entity, a sequence identifier indicating the position of the entity when continuously broadcasting the ranging signal, a time at which the entity broadcasts the ranging signal, or a combination thereof. In one implementation, for each entity, determining the distance to the entity may use the time at which the ranging signal is received from the entity and the time at which the entity broadcasts the ranging signal received in the location information from the entity. In one implementation, for each entity, determining the time at which the entity broadcasts the ranging signal may use the sequence identifier received in the location information from the entity, and determining the distance to the entity uses the time at which the ranging signal is received from the entity and the time at which the entity broadcasts the ranging signal determined using the sequence identifier.

[0060] FIG. 5 is a flow chart showing a method for supporting location determination of a UE, such as a target user equipment (UE) 102 shown in FIG. 1, FIG. 2, and FIG. 3, performed by an entity in a wireless network, such as a head SE 104-1 or SE 104-2, 106 shown in FIG. 1, FIG. 2, and FIG. 3. As shown in block 502, an available portion of a wireless spectrum is determined by the entity, which is one of a plurality of ranging sources for the UE, as described, for example, in steps 3, 5, and 7 shown in FIG. 3. In block 504, a ranging signal is generated on the available portion of the wireless spectrum, as described, for example, in steps 3, 5, and 7 shown in FIG. 3. In block 506, a ranging signal is broadcasted to be received by the UE, as described, for example, in steps 4, 6, and 8 shown in FIG. 3. In block 508, a message with location information regarding the ranging signal is broadcasted, as described, for example, in steps 9, 10, and 11 shown in FIG. 3. The message with location information may be broadcasted at a different time than the ranging signal.

[0061] In one implementation, the ranging signal is a wideband waveform comprising multiple channels, which may be adjacent or which may be non-adjacent.

[0062] In one implementation, the multiple ranging sources for the UE comprise a cluster of ranging sources that continuously broadcast ranging signals. In one implementation, the continuously broadcast ranging signals are broadcast using the same set of channels without overlap in time. In one implementation, a first ranging signal among the continuously broadcast ranging signals includes an identification of a set of channels in a preamble determined by a first ranging source among the cluster of ranging sources. In one implementation, for example, the entity may be a first ranging source among the multiple ranging sources that continuously broadcast ranging signals. In this example, the available portion of the wireless spectrum may be determined by detecting energy levels of different channels in the wireless spectrum, for example, as described in step 3 shown in FIG. 3. In this example, the ranging signal includes generating a preamble indicating a time at which the continuously broadcast ranging signal will occur. In one implementation, for example, the entity broadcasts a ranging signal after receiving a ranging signal broadcast by a ranging source that immediately precedes the entity in the continuous broadcast of the ranging signal, for example, as described in steps 5, 6, and 7, 8 shown in FIG. 3. In this example, the available portion of the wireless spectrum is determined by inspecting the waveform or preamble of a ranging signal from a preceding ranging source, for example as described in steps 5 and 7 shown in FIG.

[0063] In one implementation, messages with location information regarding the ranging signal may be broadcast in an Intelligent Transport System (ITS) spectrum.

[0064] In one implementation, the location information may include at least one of a location of the entity, a sequence identifier indicating the position of the entity among multiple ranging sources for the UE, a time at which the entity broadcasts a ranging signal, or a combination thereof.

[0065] In one implementation, the entity may be a roadside unit or a vehicle.

[0066] FIG. 6 illustrates an example of a hardware implementation of a UE 600 capable of performing location determination using continuously broadcasted ranging signals as described herein. The UE 600 may be, for example, the target UE 102 shown in FIG. 1, FIG. 2, FIG. 3, or may be part of a vehicle or a pedestrian. The UE 600 includes a wireless wide area network (WWAN) transceiver 620 including a transmitter and a receiver, such as a cellular transceiver, configured to receive PRS or SRS type ranging signals from base stations, for example, from other UEs in vehicles or on pedestrians in a wireless network. The WWAN transceiver 620 may also be configured to wirelessly communicate directly with one or more ranging source entities (SEs), such as roadside units and vehicles, as well as to receive the continuously broadcasted ranging signals and broadcasted location information, for example, using wireless communication on the 5.9 GHz ITS band under IEEE 802.11p or other suitable short-range wireless communication. The UE 600 may further include a wireless local area network (WLAN) transceiver 610 including a transmitter and a receiver that may also be used to wirelessly communicate with other entities and in some embodiments directly with a ranging source entity. The UE 600 may further include an SPS receiver 630 through which SPS signals from SPS satellites, e.g., GPS or GNSS, may be received. The UE 600 may include additional features such as a user interface 640, which may include, for example, a display, a keypad or other input devices such as a virtual keypad on a display, through which a user may interface with the UE 600.

[0067] The UE 600 further includes one or more processors 650 and memory 660, which may be coupled together with the bus 602. The one or more processors 650 and other components of the UE 600 may also be coupled together with the bus 602, a separate bus, or directly connected or coupled together using a combination of the above. The memory 660 may include executable code or software instructions that, when executed by the one or more processors 650, cause the one or more processors 650 to operate as a special purpose computer programmed to perform the techniques disclosed herein. As shown in FIG. 6, the memory 660 may include one or more components or modules that may be implemented by the one or more processors 650 to perform the methods described herein. Although the components or modules are shown as software in the memory 660 executable by the one or more processors 650, it should be understood that the components or modules may be dedicated hardware, either within the one or more processors 650 or outside the processors.

[0068] The memory 660 may include a ranging signal module 662 that, when implemented by the one or more processors 650, configures the one or more processors 650 to cause the WWAN transceiver 620 to directly receive continuously broadcast ranging signals from a set of SEs and measure the TOA of each ranging signal from each SE, e.g., as described in steps 4, 6, and 8 of FIG. 3 and block 402 of FIG. 4.

[0069] The memory 660 may further include a location information module 664 that, when implemented by the one or more processors 650, configures the one or more processors 650 to cause the WWAN transceiver 620 to directly receive messages having location information broadcasted from each entity among the multiple entities, e.g., as described in steps 9, 10, and 11 of FIG. 3 and block 404 of FIG. 4. In some implementations, the location information may be broadcasted on a spectrum, e.g., a licensed spectrum, different from the spectrum used for the ranging signal, e.g., an unlicensed spectrum, while in some implementations the location information and the ranging signal may be broadcasted on the same spectrum. The location information may include, for example, at least one of a location of the entity, a sequence identifier indicating the position of the entity in successively broadcasting the ranging signal, a time at which the entity broadcasts the ranging signal, or a combination thereof.

[0070] The memory 660 may further include a location determination module 668 that, when implemented by the one or more processors 650, configures the one or more processors 650 to estimate a position of the UE 600. For example, the location determination module 668 may include a ranging module 670 that, when implemented by the one or more processors 650, configures the one or more processors 650 to determine a distance to each entity using a ranging signal received from each entity and location information received from each entity, e.g., as described in stage 12 of FIG. 3 and block 406 of FIG. 4. For example, the distance may be determined using a time when a ranging signal is received from an entity and a time when the entity broadcasts a ranging signal received in the location information from the entity. In another example, the distance may be determined by determining a time when the entity broadcasts a ranging signal using a sequence identifier received in the location information from the entity, and then determining a distance to the entity using a time when a ranging signal is received from the entity and a time when the entity broadcasts a ranging signal determined using the sequence identifier.

[0071] The location determination module 668 may also include a positioning module 672 that, when implemented by the one or more processors 650, configures the one or more processors 650 to determine a position of the user equipment 600 based on the distance to each entity and the known location of each entity, e.g., as described in stage 13 of FIG. 3 and block 408 of FIG. 4. For example, the positioning module 672 may configure the one or more processors 650 to determine a position of the user equipment 600 using trilateration based on the distance to the entity and the position of the entity received in the location information. The positioning module 672 may further configure the one or more processors 650 to determine a position of the user equipment 600 using the SPS receiver 630 along with the distance to the entity and the position of the entity received in the location information.

[0072] In addition, the memory 660 may further include a transmission time module 666 that, when implemented by the one or more processors 650, configures the one or more processors 650 to determine a time for the entity to broadcast a ranging signal using a sequence identifier received in location information from the entity, e.g., as described in step 12 of FIG. 3 .

[0073] The methods described herein may be implemented by various means depending on the application. For example, the methods may be implemented in hardware, firmware, software, or any combination thereof. In the case of a hardware implementation, the one or more processors 650 may be implemented in 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.

[0074] For implementations of the UE 600 with firmware and / or software, the methods may be implemented with modules (e.g., procedures, functions, etc.) performing distinct functions described herein. Any machine-readable medium tangibly embodying instructions may be used in implementing the methods described herein. For example, software code that causes the one or more processors 650 to operate as a special purpose computer programmed to perform the techniques disclosed herein may be stored in a memory (e.g., memory 660) and executed by the one or more processors 650. The memory may be implemented within the one or more processors 650 or external to the one or more processors 650. The term "memory" as used herein refers to any type of long-term memory, short-term memory, volatile memory, non-volatile memory, or other memory, and should not be limited to any particular type of memory or any particular number of memories, or to any particular type of medium on which the memory is stored.

[0075] If implemented in firmware and / or software, the functions performed by the UE 600 may be stored as one or more instructions or code on a non-transitory computer-readable storage medium, such as the memory 660. Examples of storage media include computer-readable media encoded with data structures and computer-readable media encoded with a computer program. Computer-readable media include physical computer storage media. A storage medium may be any available medium that can be accessed by a computer. By way of example and not limitation, such computer-readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, semiconductor storage, or other storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer, where disk and disc as used herein include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks typically reproduce data magnetically and discs reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0076] In addition to storage on a computer-readable storage medium, instructions and / or data for the UE 600 may be provided as signals on a transmission medium included in a communication device. For example, a communication device comprising part or all of the UE 600 may include a transceiver having signals indicative of the instructions and data. The instructions and data are stored on a non-transitory computer-readable medium, e.g., memory 660, and configured to operate one or more processors 650 as a special-purpose computer programmed to perform the techniques disclosed herein. That is, the communication device includes a transmission medium having signals indicative of information for performing the disclosed functions. At a first time, the transmission medium included in the communication device may include a first portion of information for performing the disclosed functions, and at a second time, the transmission medium included in the communication device may include a second portion of information for performing the disclosed functions.

[0077] Thus, a user equipment such as UE 600 may include means for receiving ranging signals broadcasted by each entity among the multiple entities in a wireless network, which may be, for example, a WWAN transceiver 620 and one or more processors 650 having dedicated hardware such as a ranging signal module 662 or implementing executable code or software instructions in memory 660. Means for receiving messages with location information broadcasted from each entity among the multiple entities may be, for example, a WWAN transceiver 620 and one or more processors 650 having dedicated hardware such as a location information module 664 or implementing executable code or software instructions in memory 660. Means for determining a distance to each entity using the ranging signals received from each entity and the location information received from each entity may be, for example, one or more processors 650 having dedicated hardware such as a ranging module 670 or implementing executable code or software instructions in memory 660. The means for determining the position of the user equipment based on the distance to each entity and the known location of each entity may be, for example, one or more processors 650 having dedicated hardware such as a positioning module 672 or implementing executable code or software instructions in memory 660.

[0078] The user equipment may further include means for determining a time at which the entity broadcasts a ranging signal using a sequence identifier received in the location information from the entity, which may be, for example, a transmission time module 666.

[0079] FIG. 7 illustrates an example of a hardware implementation of a ranging source entity (SE) 700 capable of supporting location determination of a user equipment (UE) using continuously broadcasted ranging signals as described herein. By way of example, the SE 700 may be a fixed entity such as a roadside unit, but may alternatively be a non-fixed entity such as a vehicle having a known location. The SE 700 includes a wireless wide area network (WWAN) transceiver 720 including a transmitter and a receiver, such as a cellular transceiver, configured to wirelessly communicate directly with a target UE and broadcast ranging signals and location information to the target UE, for example, using wireless communications on the 5.9 GHz ITS band under IEEE 802.11p or other suitable short-range wireless communications. The SE 700 may further include a wireless local area network (WLAN) transceiver 710 including a transmitter and a receiver, which may also be used to wirelessly communicate directly with other entities and in some embodiments with the UE. The SE 700 may further include an SPS receiver 730 through which SPS signals from SPS satellites may be received and used to determine the position of the SE 700.

[0080] The SE 700 further includes one or more processors 740 and memory 750, which may be coupled together with the bus 702. The one or more processors 740 and other components of the SE 700 may be similarly coupled together with the bus 702, a separate bus, or may be directly connected or coupled together using a combination of the above. The memory 750 may include executable code or software instructions that, when executed by the one or more processors 740, cause the one or more processors 740 to operate as a special purpose computer programmed to perform the techniques disclosed herein. As shown in FIG. 7, the memory 750 may include one or more components or modules that may be implemented by the one or more processors 740 to perform the methods described herein. Although the components or modules are shown as software in the memory 750 executable by the one or more processors 740, it should be understood that the components or modules may be dedicated hardware, either within the one or more processors 740 or external to the processors.

[0081] The memory 750 may include a channel availability module 752 that, when implemented by the one or more processors 740, configures the one or more processors 740 to use the WWAN transceiver 720 to determine an available portion of the wireless spectrum by an entity, where the entity is one of a plurality of ranging sources for the UE, as described, for example, in steps 3, 5, and 7 of FIG. 3 and block 502 of FIG. 5. For example, the available portion of the wireless spectrum may be determined by detecting energy levels of different channels in the wireless spectrum received by the WWAN transceiver 720. In another example, the available portion of the wireless spectrum may be determined by inspecting a waveform or preamble of a ranging signal from a preceding ranging source.

[0082] The memory 750 may include a ranging signal generation module 754 that, when implemented by the one or more processors 740, configures the one or more processors 740 to generate a ranging signal on an available portion of the wireless spectrum, e.g., as described in stages 3, 5, and 7 of FIG. 3 and block 504 of FIG. 5. The ranging signal may be a wideband waveform having multiple channels that may be adjacent or non-adjacent. The one or more processors 740 may be configured to generate the ranging signal to include a preamble indicating the time when the continuously broadcasted ranging signal will occur, e.g., as described in stage 3 of FIG. 3.

[0083] The memory 750 may include a ranging signal broadcast module 756 that, when implemented by the one or more processors 740, configures the one or more processors 740 to use the WWAN transceiver 720 to broadcast a ranging signal to be received by the UE, e.g., as described in steps 4, 6, and 8 of FIG. 3 and block 506 of FIG. 5. The ranging signal may be broadcast, for example, on an unlicensed spectrum. The broadcast of the ranging signal may be part of a successive broadcast of ranging signals by multiple SEs in the set of SEs, where the ranging signal is broadcast after receiving a ranging signal broadcast by a ranging source immediately preceding the entity in the successive broadcast of the ranging signal.

[0084] The memory 750 may include a location information broadcast module 758 that, when implemented by the one or more processors 740, configures the one or more processors 740 to use the WWAN transceiver 720 to broadcast a message having location information regarding the ranging signal, e.g., as described in steps 9, 10, and 11 of FIG. 3 and block 508 of FIG. 5. The location information may be broadcast, for example, in an Intelligent Transport System (ITS) spectrum. The location information may include at least one of a location of the entity, a sequence identifier indicating the position of the entity among multiple ranging sources for the UE, a time at which the entity broadcasts the ranging signal, or a combination thereof.

[0085] The methods described herein may be implemented by various means depending on the application. For example, the methods may be implemented in hardware, firmware, software, or any combination thereof. In the case of a hardware implementation, the one or more processors 740 may be implemented in 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.

[0086] For implementations of the SE700 with firmware and / or software, the methods may be implemented with modules (e.g., procedures, functions, and so on) performing the distinct functions described herein. Any machine-readable medium tangibly embodying instructions may be used in implementing the methods described herein. For example, software code that causes one or more processors 740 to operate as a special purpose computer programmed to perform the techniques disclosed herein may be stored in a memory (e.g., memory 750) and executed by the one or more processors 740. The memory may be implemented within the one or more processors 740 or external to the one or more processors 740. The term "memory" as used herein refers to any type of long-term memory, short-term memory, volatile memory, non-volatile memory, or other memory, and should not be limited to any particular type of memory or any particular number of memories, or to any particular type of medium on which the memory is stored.

[0087] If implemented in firmware and / or software, the functions performed by the SE 700 may be stored as one or more instructions or code on a non-transitory computer-readable storage medium, such as memory 750. Examples of storage media include computer-readable media encoded with data structures and computer-readable media encoded with a computer program. Computer-readable media include physical computer storage media. Storage media may be any available medium that can be accessed by a computer. By way of example and not limitation, such computer-readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, semiconductor storage, or other storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer, where disk and disc as used herein include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks typically reproduce data magnetically and discs reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0088] In addition to storage on a computer-readable storage medium, instructions and / or data for the SE 700 may be provided as signals on a transmission medium included in a communications device. For example, a communications device comprising some or all of the SE 700 may include a transceiver having signals indicative of the instructions and data. The instructions and data are stored on a non-transitory computer-readable medium, e.g., memory 750, and configured to operate one or more processors 740 as a special-purpose computer programmed to perform the techniques disclosed herein. That is, the communications device includes a transmission medium having signals indicative of information for performing the disclosed functions. At a first time, the transmission medium included in the communications device may include a first portion of information for performing the disclosed functions, and at a second time, the transmission medium included in the communications device may include a second portion of information for performing the disclosed functions.

[0089] Thus, an SE such as SE 700 may include means for determining an available portion of a wireless spectrum by an entity, the entity being one of multiple ranging sources for a UE, which may be, for example, a WWAN transceiver 720 and one or more processors 740 having dedicated hardware such as a channel availability module 752 or implementing executable code or software instructions in memory 750. Means for generating a ranging signal on an available portion of a wireless spectrum may be, for example, one or more processors 740 having dedicated hardware such as a ranging signal generation module 754 or implementing executable code or software instructions in memory 750. Means for broadcasting a ranging signal to be received by the UE may be, for example, a WWAN transceiver 720 and one or more processors 740 having dedicated hardware such as a ranging signal broadcast module 756 or implementing executable code or software instructions in memory 750. The means for broadcasting a message having location information regarding the ranging signal may be, for example, a WWAN transceiver 720 and one or more processors 740 having dedicated hardware such as a location information broadcast module 758 or implementing executable code or software instructions in memory 750.

[0090] References throughout this specification to "one example," "one example," "some examples," or "exemplary implementations" mean that a particular feature, structure, or characteristic described with respect to a feature and / or example may be included in at least one feature and / or example of the claimed subject matter. Thus, the appearances of the phrases "in one example," "in one example," "some examples," or "in some implementations" or other similar phrases in various places throughout this specification do not necessarily all refer to the same features, examples, and / or limitations. Furthermore, particular features, structures, or characteristics may be combined in one or more examples and / or characteristics.

[0091] Some portions of the detailed description contained herein are presented in terms of algorithms or symbolic representations of operations on binary digital signals stored in a memory of a specific apparatus or a dedicated computing device or platform. In the context of this particular specification, the term specific apparatus or the like includes a general purpose computer that, when programmed, performs specific operations according to instructions from program software. Algorithmic descriptions or symbolic representations are examples of techniques used by those skilled in the signal processing or related arts to convey the substance of their work to others skilled in the art. An algorithm is herein, and generally, considered to be a self-consistent sequence of operations or similar signal processing that leads to a desired result. In this context, operations or processing involve physical manipulations of physical quantities. Typically, though not necessarily, such quantities may take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, or otherwise manipulated. It has proven convenient at times, primarily for reasons of common usage, to refer to such signals as bits, data, values, elements, symbols, characters, terms, numbers, numeric values, or the like. It should be understood, however, that all of these or similar terms are to be associated with the appropriate physical quantities and are merely convenient labels. Unless otherwise indicated, and as will be apparent from the description herein, it should be appreciated that throughout this specification, descriptions utilizing terms such as "processing," "calculating," "computing," "determining," and the like refer to the actions or processes of a particular apparatus, such as a special purpose computer, a special purpose computing apparatus, or a similar special purpose electronic computing device. Thus, in the context of this specification, a special purpose computer or a similar special purpose electronic computing device is capable of manipulating or transforming signals, which are typically represented as physical electronic or magnetic quantities in the memory, registers, or other information storage, transmission, or display devices of the special purpose computer or similar special purpose electronic computing device.

[0092] In the above detailed description, numerous specific details have been set forth to provide a thorough understanding of the claimed subject matter. However, it will be understood by those skilled in the art that the claimed subject matter may be practiced without these specific details. In other instances, methods and apparatuses that would be known to those skilled in the art have not been described in detail so as not to obscure the claimed subject matter.

[0093] The terms "and," "or," and "and / or" as used herein may include a variety of meanings that are expected to depend at least in part on the context in which such terms are used. Typically, when "or" is used to relate a list such as A, B, or C, it is intended to mean A, B, and C, which are used herein in an inclusive sense, as well as A, B, or C, which are used herein in an exclusive sense. In addition, the term "one or more" as used herein may be used to describe any feature, structure, or characteristic in the singular, or may be used to describe a plurality of features, structures, or characteristics, or some other combination of features, structures, or characteristics. It should be noted, however, that this is merely an illustrative example, and claimed subject matter is not limited to this example.

[0094] While what are presently considered to be exemplary features have been illustrated and described, it would be understood by those skilled in the art that various other modifications could be made and equivalents substituted without departing from the claimed subject matter. Additionally, many modifications may be made to adapt a particular situation to the teachings of the claimed subject matter without departing from the central concept described herein.

[0095] It is therefore intended that the claimed subject matter not be limited to the particular examples disclosed, but that such claimed subject matter may include all embodiments falling within the scope of the appended claims and equivalents thereof. [Explanation of symbols]

[0096] 100 Wireless communication system 102 target user equipment (UE), target UE 104 Entity, Roadside Unit (RSU), RSU, SE 104-1 Entity, First RSU, SE, Roadside Unit, RSU, Head SE 104-2 Entity, Second RSU, SE, Roadside Unit, RSU 105 Vehicle-to-Infrastructure (V2I) Communication Links 106 Entities, Vehicles, SE 107 Vehicle-to-Vehicle (V2V) communication links 200 Wireless Communication System 201 RF signal 202 RF signal, circle 203 RF signal 204 yen 206 yen 300 Call Flow 600 UE, User Equipment 602 Bus 610 Wireless Local Area Network (WLAN) Transceiver 620 Wireless Wide Area Network (WWAN) Transceiver, WWAN Transceiver 630 SPS Receiver 640 User Interface 650 One or more processors 660 Memory 662 Ranging Signal Module 664 Location Information Module 666 Transmission Time Module 668 Location Determination Module 670 Range Finder Module 672 Positioning Module 700 Ranging Source Entity (SE) 702 Bus 710 Wireless Local Area Network (WLAN) Transceiver 720 Wireless Wide Area Network (WWAN) Transceiver, WWAN Transceiver 730 SPS Receiver 740 One or more processors 750 Memory 752 Channel Availability Module 754 Ranging signal generation module 756 Ranging Signal Broadcast Module 758 Location Information Broadcast Module

Claims

1. 1. A method for performing location determination by a user equipment (UE), comprising: receiving ranging signals broadcast by each entity among a plurality of entities in a wireless network, the plurality of entities comprising a cluster of entities that continuously broadcast ranging signals, the continuously broadcast ranging signals being broadcast using a same set of channels without time overlap, and a first ranging signal among the continuously broadcast ranging signals including an identification of the set of channels in a preamble determined by a first entity among the cluster of entities; receiving a message having location information broadcast from each entity in the plurality of entities; determining a distance to each entity using the ranging signal received from each entity and the location information received from each entity; determining a location of the user equipment based on the distance to each entity and the known location of each entity; A method for providing the above.

2. 10. The method of claim 1, wherein each ranging signal broadcast by each entity is a wideband waveform comprising multiple channels.

3. The method of claim 2 , wherein the multiple channels are adjacent.

4. The method of claim 2 , wherein the multiple channels are non-contiguous.

5. The method of claim 1 , wherein each entity in the plurality of entities comprises a roadside unit or a vehicle.

6. The method of claim 1 , wherein each message having the location information is received from a respective entity in an Intelligent Transport System (ITS) spectrum.

7. 2. The method of claim 1, wherein the location information broadcast by an entity comprises at least one of the known location of the entity, a sequence identifier indicating a position of the entity when successively broadcasting the ranging signal, a time at which the entity broadcasts the ranging signal, or a combination thereof.

8. 8. The method of claim 7, wherein for each entity, the step of determining the distance to the entity uses a time at which a ranging signal is received from the entity and the time at which the entity broadcasts the ranging signal received in the location information from the entity.

9. 8. The method of claim 7, further comprising: for each entity, determining the time at which the entity broadcasts the ranging signal using the sequence identifier received in the location information from the entity, wherein determining the distance to the entity uses the time at which a ranging signal is received from the entity and the time at which the entity broadcasts the ranging signal determined using the sequence identifier.

10. 1. A user equipment (UE) configured to support location determination, comprising: A means for receiving ranging signals broadcast by each entity among a plurality of entities in a wireless network, the plurality of entities comprising a cluster of entities that continuously broadcast ranging signals, the continuously broadcast ranging signals being broadcast using a same set of channels without time overlap, and a first ranging signal among the continuously broadcast ranging signals including an identification of the set of channels in a preamble determined by a first entity among the cluster of entities; means for receiving a message having location information broadcast from each entity in the plurality of entities; means for determining a distance to each entity using the ranging signal received from each entity and the location information received from each entity; means for determining a location of the user equipment based on the distance to each entity and the known location of each entity; A UE equipped with

11. The UE of claim 10, wherein each ranging signal broadcast by each entity is a wideband waveform comprising multiple channels.

12. 11. The UE of claim 10, wherein the location information comprises at least one of a location of the entity, a sequence identifier indicating a position of the entity when successively broadcasting the ranging signal, a time at which the entity broadcasts the ranging signal, or a combination thereof, and wherein for each entity, the means for determining the distance to the entity uses a time at which a ranging signal is received from the entity and the time at which the entity broadcasts the ranging signal received in the location information from the entity.

13. 11. The UE of claim 10, wherein the location information comprises at least one of a location of the entity, a sequence identifier indicating the position of the entity when continuously broadcasting the ranging signal, a time at which the entity broadcasts the ranging signal, or a combination thereof, and the UE further comprises means for determining the time at which the entity broadcasts the ranging signal using the sequence identifier received in the location information from the entity, and wherein the means for determining the distance to the entity uses the time at which a ranging signal is received from the entity and the time at which the entity broadcasts the ranging signal determined using the sequence identifier.

14. 10. A non-transitory computer-readable storage medium having program code stored thereon operable to configure at least one processor in a user equipment (UE) to perform location determination according to the method of any one of claims 1 to 9.

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